JP2016219358A - Composition for power storage device, slurry for power storage device, separator for power storage device, power storage device electrode and power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a protective film on a surface of a separator or an electrode, which suppresses thermal contraction of a separator and is excellent in permeability and liquid retention of an electrolyte solution and can suppress increase in internal resistance of the electricity storage device. Provided are a composition and a slurry for an electricity storage device containing the composition. Also provided are a composition for an electricity storage device for producing an electricity storage device electrode having excellent adhesiveness and charge/discharge characteristics, and a slurry for an electricity storage device containing the composition. The composition for an electricity storage device according to the present invention is characterized by containing polymer particles (A), a metal complex salt (B), and a liquid medium (C). [Selection diagram] None

Description

  The present invention relates to an electrical storage device composition, an electrical storage device slurry, an electrical storage device separator, an electrical storage device electrode, and an electrical storage device.

  In recent years, a power storage device having a high voltage and a high energy density has been required as a power source for driving electronic equipment. In particular, lithium ion batteries and lithium ion capacitors are expected as power storage devices having high voltage and high energy density.

  The electricity storage device having such a high voltage and high energy density is required to be further downsized. In order to achieve miniaturization of an electricity storage device, it is essential not only to reduce the thickness of power generation elements such as a positive electrode and a negative electrode, but also to reduce the thickness of a separator or the like that separates the positive electrode and the negative electrode. However, when the interval between the positive electrode and the negative electrode is reduced due to the miniaturization of the electricity storage device, there may be a problem that a short circuit is likely to occur.

  In the event of an abnormality such as a short circuit or overcharge, there is a greater risk of excessive heat generation than before due to the high voltage and high energy density of the electricity storage device. For this reason, the electric storage device is provided with several means for ensuring safety even in the event of an abnormality, and one of them is a separator shutdown function. The shutdown function is a function that suppresses excessive heat generation by stopping the battery reaction by blocking the movement of ions when the temperature of the battery rises for some reason and blocking the movement of ions. In particular, one of the reasons why polyethylene porous membranes are frequently used as power storage device separators using metal ions such as lithium ions is that they have an excellent shutdown function. However, as the electricity storage device increases in voltage and energy density, the amount of heat generated during abnormal heat generation increases rapidly, and when the temperature suddenly reaches high temperatures or when heat is required after shutdown and the high temperature state is maintained for a long time. There is. In such a case, there is a risk that the separator contracts or breaks and short-circuits between the positive and negative electrodes, causing further heat generation.

  In order to avoid such a phenomenon, for example, in Patent Document 1 and Patent Document 2, a technique for improving battery characteristics by melting and kneading a polymer and inorganic particles to form a microporous film on a porous separator substrate. Is being considered. On the other hand, Patent Document 3 discusses a technique for improving battery characteristics by forming a porous protective film on at least one surface of a positive electrode and a negative electrode. Moreover, in patent document 4, the technique which improves a battery characteristic is laminated | stacked by laminating | stacking the porous film containing a polymer and nonelectroconductive particle on an organic separator base material.

  Recently, from the viewpoint of achieving the demand for higher output and higher energy density of power storage devices, studies are being made on the use of materials with large lithium storage capacity. For example, an approach to improve the lithium occlusion amount by using graphite having higher crystallinity as an active material and to realize a capacity close to the theoretical occlusion amount (about 370 mAh / g) of the carbon material is being advanced. . On the other hand, Patent Document 5 discloses an approach in which a silicon material having a maximum lithium occlusion amount of about 4200 mAh / g is used as an active material. In any case, it is considered that the capacity of the electricity storage device is greatly improved by utilizing such an active material having a large lithium storage amount.

However, an active material using such a material having a large amount of lithium storage is accompanied by a large volume change due to the storage and release of lithium. For this reason, when the conventionally used binder for electrodes is applied to such a material having a large lithium storage amount, the adhesive cannot be maintained, and the active material is peeled off. Capacity drop occurs.

International Publication No. 2006/0253323 JP 2008-214425 A JP 2009-54455 A International Publication No. 2010/074202 JP 2004-185810 A

  However, according to the prior art using inorganic particles as described in the above-mentioned Patent Documents 1 to 4, the protective film is formed on the separator or electrode surface, which is caused by dendrite generated along with charge / discharge. Although the short circuit can be suppressed, when the separator hole closes due to abnormal heat generation and the shutdown function is exhibited, the separator causes thermal contraction, and the positive electrode and the negative electrode are short-circuited at the contracted portion, so that the shutdown function is sufficiently developed. There was a risk of not doing.

  Accordingly, some embodiments according to the present invention provide a protective film that suppresses thermal contraction of the separator, is excellent in electrolyte permeability and liquid retention, and can suppress an increase in internal resistance of the electricity storage device. The composition for electrical storage devices for forming on the surface, and the slurry for electrical storage devices containing this composition are provided.

  On the other hand, the electrode binder described in the above-mentioned Patent Document 5 does not have sufficient adhesion to put an active material using a material having a large amount of lithium occlusion into practical use, and the electrode characteristics are improved by repeated charge and discharge. Due to the deterioration, there is a problem that the durability required for practical use cannot be obtained sufficiently.

  Accordingly, some embodiments according to the present invention provide a composition for an electricity storage device for producing an electricity storage device electrode having excellent adhesion and charge / discharge characteristics, and a slurry for an electricity storage device containing the composition. is there.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1]
One aspect of the composition for an electricity storage device according to the present invention is:
Polymer particles (A);
A metal complex salt (B),
A liquid medium (C);
It is characterized by containing.

[Application Example 2]
In the composition for an electricity storage device of Application Example 1,
The metal contained in the metal complex salt (B) may be a polyvalent metal.

[Application Example 3]
In the composition for an electricity storage device of Application Example 1 or Application Example 2,
The metal complex salt (B) may contain at least one metal selected from the group consisting of titanium, zirconium, aluminum, tin, and zinc.

[Application Example 4]
In the composition for an electricity storage device of any one of Application Examples 1 to 3,
The polymer particles (A) can have an ionic functional group.

[Application Example 5]
In the composition for an electricity storage device of Application Example 4,
The ionic functional group may be at least one functional group selected from the group consisting of a sulfo group, a carboxy group, a hydroxyl group, an amino group, a phosphate group, and a salt group thereof.

[Application Example 6]
In the composition for an electricity storage device of Application Example 4 or Application Example 5,
When the amount of the ionic functional group of the polymer particles (A) is Ma mol and the content of the metal complex salt (B) is Mb mol, Mb / Ma = 0.1 to 15 can be obtained.

[Application Example 7]
In the composition for an electricity storage device of any one of Application Examples 1 to 6,
The amount of ionic functional groups per 100 g of the polymer particles (A) may be 0.001 to 1.2 mol.

[Application Example 8]
In the composition for an electricity storage device of any one of Application Examples 1 to 7,
The toluene insoluble content at 50 ° C. of the polymer particles (A) may be 90% or more.

[Application Example 9]
In the composition for an electricity storage device of any one of Application Examples 1 to 8,
The said polymer particle (A) can contain the polymer particle (A1) which contains less than 15 mass parts of repeating units derived from the compound which has two or more polymerizable unsaturated groups in 100 mass parts.

[Application Example 10]
In the composition for an electricity storage device of Application Example 9,
The polymer particles (A1) may further contain a repeating unit derived from a monomer having a fluorine atom and a repeating unit derived from an unsaturated carboxylic acid.

[Application Example 11]
In the composition for an electricity storage device of Application Example 9,
The polymer particle (A1) is a repeating unit derived from an unsaturated carboxylic acid, a repeating unit derived from an unsaturated carboxylic acid ester, a repeating unit derived from an aromatic vinyl compound, and a repeating derived from a conjugated diene compound. And a unit.

[Application Example 12]
In the composition for an electricity storage device of any one of Application Examples 1 to 11,
The polymer particles (A) contain polymer particles (A2) containing 20 to 100 parts by mass of repeating units derived from a compound having two or more polymerizable unsaturated groups in 100 parts by mass. Can do.

[Application Example 13]
In the composition for an electricity storage device of Application Example 12,
The polymer particle (A2) is a repeating unit derived from an unsaturated carboxylic acid ester (excluding a compound having two or more polymerizable unsaturated groups) and an aromatic vinyl compound (two or more polymerizable unsaturated groups). At least one of the repeating units derived from (2).

[Application Example 14]
In the composition for an electricity storage device of any one of Application Example 9 to Application Example 13,
The compound having two or more polymerizable unsaturated groups may be at least one compound selected from the group consisting of polyfunctional (meth) acrylic acid esters and aromatic polyfunctional vinyl compounds.

[Application Example 15]
One aspect of the slurry for an electricity storage device according to the present invention is:
It contains the composition for electrical storage devices of any one of the application examples 1 thru | or the application example 14, and an inorganic filler.

[Application Example 16]
In the slurry for the electricity storage device of Application Example 15,
The inorganic filler may be at least one particle selected from the group consisting of silica, titanium oxide, aluminum oxide, zirconium oxide, and magnesium oxide.

[Application Example 17]
One aspect of the separator for an electricity storage device according to the present invention is:
A layer formed by applying and drying the slurry for an electricity storage device of Application Example 15 or Application Example 16 is provided on the surface.

[Application Example 18]
One aspect of the electricity storage device according to the present invention is:
The power storage device separator according to Application Example 17 is provided.

[Application Example 19]
One aspect of the slurry for an electricity storage device according to the present invention is:
It contains the composition for electrical storage devices of any one example of the application example 1 thru | or the application example 14, and an active material, It is characterized by the above-mentioned.

[Application Example 20]
One aspect of the electrode for an electricity storage device according to the present invention is:
It is characterized by comprising a current collector and a layer formed by applying and drying the electricity storage device slurry of Application Example 19 on the surface of the current collector.

[Application Example 21]
One aspect of the electricity storage device according to the present invention is:
The electrode for an electricity storage device of Application Example 20 is provided.

The composition for an electricity storage device according to the present invention can also be used as a material for forming a protective film for suppressing a short circuit caused by dendrites generated during charging and discharging, and the binding ability between active materials. And it can also be used as a material for producing the electrical storage device electrode which improved the adhesion capability of an active material and an electrical power collector, and powder fall resistance. By forming a protective film on the surface of the separator or electrode using the composition for an electricity storage device according to the present invention, the thermal contraction of the separator is effectively suppressed, and the electrolyte has excellent permeability and liquid retention, An increase in resistance can be suppressed. Thereby, since the degree to which the internal resistance of the electricity storage device increases due to repeated charge / discharge or overcharge is reduced, an electricity storage device having excellent charge / discharge characteristics can be obtained.

  Moreover, the electrical storage device electrode which is excellent in adhesiveness and charging / discharging characteristic can be produced by forming an active material layer using the composition for electrical storage devices according to the present invention.

It is the schematic diagram which showed the cross section of the electrical storage device which concerns on 1st Embodiment. It is the schematic diagram which showed the cross section of the electrical storage device which concerns on 2nd Embodiment. It is the schematic diagram which showed the cross section of the electrical storage device which concerns on 3rd Embodiment. 10 is a TGA chart of polymer particles (A2) obtained in Synthesis Example 12.

  Hereinafter, preferred embodiments according to the present invention will be described in detail. It should be understood that the present invention is not limited to only the embodiments described below, and includes various modifications that are implemented without departing from the scope of the present invention. In this specification, “(meth) acrylic acid” is a concept encompassing both “acrylic acid” and “methacrylic acid”. Further, “˜ (meth) acrylic acid ester” is a concept encompassing both “˜acrylic acid ester” and “˜methacrylic acid ester”.

1. Composition for electrical storage device The composition for electrical storage devices which concerns on this embodiment is characterized by containing a polymer particle (A), a metal complex salt (B), and a liquid medium (C). The composition for an electricity storage device according to the present embodiment can be used as a material for forming a protective film for suppressing a short circuit caused by dendrite that occurs in association with charge / discharge, or a combination of active materials. It can also be used as a material for producing an electricity storage device electrode (active material layer) having improved ability, adhesion between the active material and the current collector, and powder fall resistance. Hereafter, each component contained in the composition for electrical storage devices which concerns on this embodiment is demonstrated in detail.

1.1. Polymer particles (A)
The composition for an electricity storage device according to the present embodiment contains polymer particles (A). The polymer particle (A) preferably has a surface functional group. When polymer particle (A) has a surface functional group, a bridge | crosslinking is formed by the effect | action of the metal complex salt (B) mentioned later, and the network between polymers can be constructed | assembled. Thereby, the elasticity modulus and heat resistance of a protective film or an active material layer can be improved.

  The surface functional group of the polymer particle (A) is preferably an ionic functional group. When the surface functional group is an ionic functional group, it can be easily chelated with the metal complex salt (B) described later, and a metal crosslinked structure is constructed. Thereby, it is estimated that the protective film which can suppress the thermal contraction of a separator effectively is formed. In addition, since the polymer particles (A) and a metal complex salt (B) described later form an ionic bond, a protective film with stronger and stronger adhesion can be produced on the separator, and the protective film is peeled off. It can be presumed that the heterogeneity of the separator due to the above can be effectively suppressed, and the deterioration of the charge / discharge characteristics can be suppressed even if the charge / discharge cycles are repeated. The “ionic functional group” means a functional group that forms a cation or an anion in water.

  The polymer particles (A) having such an ionic functional group are required to have a protective film produced in a timely manner as long as they contain a monomer (monomer, polymer repeating structural unit) containing an ionic functional group. It can be selected and used according to the characteristics. For example, it may be obtained from a living body such as at least one selected from the group consisting of polypeptides, nucleic acids, and polysaccharides, or a complex thereof, or may be polymer particles (A1) or (A2) described later. It may be an artificially synthesized material such as

  The ionic functional group is not particularly limited, but may be at least one functional group selected from the group consisting of a sulfo group, a carboxy group, a hydroxyl group, an amino group, a phosphate group, and a salt group thereof. preferable. By using the polymer particle (A) having such an ionic functional group, the ionic functional group present on the surface of the polymer particle (A) and the metal ion of the metal complex salt (B) described later are ionized. Bonds can be formed. Since the polymer particles (A) are firmly bound in the protective film through such ionic bonds, the separator is heated when the pores of the separator are closed due to abnormal heat generation of the electricity storage device and the shutdown function is exhibited. Shrinkage can be effectively suppressed.

  The amount of the ionic functional group per 100 g of the polymer particles (A) is preferably 0.001 to 1.2 mol, more preferably 0.005 to 1 mol, and 0.01 to 0. It is particularly preferable to contain 9 mol. When the amount of the ionic functional group per 100 g of the polymer particles (A) is in the above range, the storage stability of the composition for the electricity storage device can be further improved by electrostatic repulsion and steric hindrance effect, and the electricity storage device Since the concentration of metal ions liberated in the electrolyte solution can be suppressed, a power storage device having better charge / discharge rate characteristics can be manufactured.

<Toluene insoluble matter>
The toluene insoluble content at 50 ° C. of the polymer particles (A) is preferably 85% or more, more preferably 90% or more, and particularly preferably 100%, that is, not dissolved. It is presumed that the toluene insoluble content is approximately proportional to the amount of insoluble content in the electrolytic solution used in the electricity storage device. For this reason, if a toluene insoluble content is the said range, even if it manufactures an electrical storage device and it repeats charging / discharging over a long period of time, since it can suppress the elution of the polymer to electrolyte solution, it can be estimated that it is favorable.

The toluene insoluble content can be calculated as follows. 10 g of the aqueous dispersion containing the polymer particles (A) is weighed into a Teflon (registered trademark) petri dish having a diameter of 8 cm and dried at 120 ° C. for 1 hour to form a film. 1 g of the obtained film (polymer) is immersed in 400 mL of toluene and shaken at 50 ° C. for 3 hours. Next, the toluene phase was filtered through a 300-mesh wire mesh to separate insoluble components, and the weight (Y (g)) of the residue obtained by evaporating and removing the dissolved toluene was measured. The toluene insoluble matter is obtained by 1).
Toluene insoluble content (%) = ((1-Y) / 1) × 100 (1)

<Temperature for reducing 10% by weight in an air atmosphere (T ₁₀ )>
The temperature (T ₁₀ ) at which the weight of the polymer particles (A) is reduced by 10% by weight in an air atmosphere is preferably 320 ° C. or higher, and more preferably 350 ° C. or higher. The temperature (T ₁₀ ) at which the weight of the polymer particles (A) is reduced by 10% by weight in an air atmosphere is presumed to correlate with the chemical stability against oxidation at high temperature and high voltage inside the battery. Therefore, if the temperature (T ₁₀ ) at which the weight of the polymer particles (A) is reduced by 10% by weight in an air atmosphere is within the above temperature range, the stability against oxidation at high temperature and high voltage inside the battery is improved. As a result, the decomposition reaction of the polymer particles (A) is difficult to occur, so that the remaining capacity ratio is improved.

The temperature (T ₁₀ ) at which the weight of the polymer particles (A) is reduced by 10% by weight in an air atmosphere can be measured as follows. 10 g of an aqueous dispersion containing polymer particles (A) was weighed into a Teflon (registered trademark) petri dish having a diameter of 8 cm and dried at 120 ° C. for 1 hour to form a film. The obtained film (polymer) is pulverized into powder, and this powder is subjected to thermogravimetric analysis with a thermal analyzer (for example, model “DTG-60A” manufactured by Shimadzu Corporation). As a result, the temperature at which the weight of the polymer particles (A) is reduced by 10% by weight in the air atmosphere when heated at a heating rate of 20 ° C./min in an air atmosphere is defined as (T ₁₀ ).

  The polymer particles (A) may be prepared by appropriately adjusting the monomer polymerization method. In addition, the polymer particles (A) may contain only the polymer particles (A1) shown below, may contain only the polymer particles (A2) shown below, or the polymer particles ( Both A1) and polymer particles (A2) may be contained, but from the viewpoint of more effectively suppressing thermal shrinkage of the separator, both polymer particles (A1) and polymer particles (A2) are contained. It is preferable to do.

1.1.1. Polymer particles (A1)
The polymer particles (A1) may have a repeating unit content of less than 15 parts by mass derived from a compound having two or more polymerizable unsaturated groups in 100 parts by mass of the particles. It is preferable that there is 0 part by mass, that is, it is more preferable not to contain substantially. When the repeating unit derived from the compound having two or more polymerizable unsaturated groups is in the above range, the flexibility of the polymer particles (A1) increases, and the adhesion between the polymer particles and the separator and the electrode Since adhesiveness becomes favorable, it is preferable.

  Although it does not restrict | limit especially as a compound which has two or more polymerizable unsaturated groups, For example, a polyfunctional (meth) acrylic acid ester, an aromatic polyfunctional vinyl compound, etc. are mentioned.

  Examples of the polyfunctional (meth) acrylic acid ester include compounds represented by the following general formula (2), (poly) (meth) acrylic acid esters of polyhydric alcohols, and other polyfunctional monomers.

（上記一般式（２）中、Ｒ^１は水素原子またはメチル基であり、Ｒ^２は重合性の炭素−炭素不飽和結合、エポキシ基及び水酸基よりなる群から選ばれる少なくとも１種の官能基を有する、炭素数１〜１８の有機基である。）

(In the general formula (2), R ¹ represents a hydrogen atom or a methyl group, and R ² represents at least one functional group selected from the group consisting of a polymerizable carbon-carbon unsaturated bond, an epoxy group and a hydroxyl group. It is an organic group having 1 to 18 carbon atoms.)

Preferable specific examples of R ^{2 in} the general formula (2) include, for example, vinyl group, isopropenyl group, allyl group, (meth) acryloyl group, epoxy group, glycidyl group, hydroxyalkyl group and the like.

Polyfunctional (meth) acrylic acid esters include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, hexa ( 1) selected from these, such as dipentaerythritol (meth) acrylate, glycidyl (meth) acrylate, hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, allyl (meth) acrylate, and the like. It can be more than a seed. Of these,
It is preferably at least one selected from the group consisting of ethylene glycol methacrylate, trimethylolpropane tri (meth) acrylate and allyl (meth) acrylate, and is ethylene glycol di (meth) acrylate. It is particularly preferred. The polyfunctional (meth) acrylic acid ester exemplified above may be used alone or in combination of two or more.

  As the aromatic polyfunctional vinyl compound, for example, a compound represented by the following general formula (3) can be preferably used.

（上記一般式（３）中、複数存在するＲ^３はそれぞれ独立に、重合性の炭素―炭素不飽和結合を有する有機基であり、複数存在するＲ^４はそれぞれ独立に、炭素数１〜１８の炭化水素基である。ｎは２〜６の整数であり、ｍは０〜４の整数である。）

(In the general formula (3), a plurality of R ³ are each independently an organic group having a polymerizable carbon-carbon unsaturated bond, and a plurality of R ⁴ are each independently represented by 1 to 18 carbon atoms. And n is an integer of 2 to 6, and m is an integer of 0 to 4.)

Examples of R ³ in the general formula (3) include a vinylene group having 2 to 12 carbon atoms, an allyl group, a vinyl group, and an isopropenyl group, and among these, a vinylene group having 2 to 12 carbon atoms. It is preferable that Examples of R ⁴ in the general formula (3) include a methyl group and an ethyl group.

  Examples of the aromatic polyfunctional vinyl compound include aromatic divinyl compounds such as divinylbenzene and diisopropenylbenzene, but are not limited thereto. Of these, divinylbenzene is preferred. The aromatic polyfunctional vinyl compounds exemplified above may be used alone or in combination of two or more.

  The polymer particles (A1) function as a binder for closely adhering polymer particles (A2) to be described later, and further function as a binder for closely adhering the separator, electrode, and protective film. When the polymer particle (A1) functions as such a binder, it is preferably a solid particle having no pores inside the particle. By being solid particles, better binder properties can be expressed. The polymer particles (A1) can be roughly classified into “fluorinated polymer particles” and “diene polymer particles” depending on the types of repeating units contained.

  Hereinafter, the monomer constituting the repeating unit contained in each polymer particle (A1), the mode of the polymer particle (A1), the production method, and the like will be described in detail.

1.1.1.1. Fluorine-containing polymer particles <monomer having fluorine atoms>
The fluorine-containing polymer particles contain a repeating unit derived from a monomer having a fluorine atom. Examples of the monomer having a fluorine atom include an olefin compound having a fluorine atom and a (meth) acrylic acid ester having a fluorine atom. Examples of the olefin compound having a fluorine atom include vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, ethylene trifluoride chloride, and perfluoroalkyl vinyl ether. As the (meth) acrylic acid ester having a fluorine atom, for example, a compound represented by the following general formula (4), (meth) acrylic acid 3 [4 [1-trifluoromethyl-2,2-bis [bis (tri Fluoromethyl) fluoromethyl] ethynyloxy] benzooxy] 2-hydroxypropyl and the like.

（上記一般式（４）中、Ｒ^５は水素原子またはメチル基であり、Ｒ^６はフッ素原子を含有する炭素数１〜１８の炭化水素基である。）

(In the general formula (4), R ⁵ is a hydrogen atom or a methyl group, and R ⁶ is a C 1-18 hydrocarbon group containing a fluorine atom.)

Examples of R ⁶ in the general formula (4) include a fluorinated alkyl group having 1 to 12 carbon atoms, a fluorinated aryl group having 6 to 16 carbon atoms, and a fluorinated aralkyl group having 7 to 18 carbon atoms. Among these, a fluorinated alkyl group having 1 to 12 carbon atoms is preferable. Preferable specific examples of R ^{6 in} the general formula (4) include, for example, 2,2,2-trifluoroethyl group, 2,2,3,3,3-pentafluoropropyl group, 1,1,1, 3,3,3-hexafluoropropan-2-yl group, β- (perfluorooctyl) ethyl group, 2,2,3,3-tetrafluoropropyl group, 2,2,3,4,4,4- Hexafluorobutyl group, 1H, 1H, 5H-octafluoropentyl group, 1H, 1H, 9H-perfluoro-1-nonyl group, 1H, 1H, 11H-perfluoroundecyl group, perfluorooctyl group, etc. Can do. Of these, the monomer having a fluorine atom is preferably an olefin compound having a fluorine atom, more preferably at least one selected from the group consisting of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene. preferable. The monomer having a fluorine atom may be used alone or in combination of two or more.

  The content ratio of the repeating unit derived from the monomer having a fluorine atom in 100 parts by mass of the fluorine-containing polymer particles is preferably 5 to 50 parts by mass, and more preferably 15 to 40 parts by mass. It is especially preferable that it is 20-30 mass parts.

<Unsaturated carboxylic acid>
The fluorine-containing polymer particles preferably contain a repeating unit derived from an unsaturated carboxylic acid in addition to the repeating unit derived from the monomer having a fluorine atom. Examples of the unsaturated carboxylic acid include monocarboxylic acids or dicarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid, and one or more selected from these are used. can do. As the unsaturated carboxylic acid, it is preferable to use one or more selected from acrylic acid and methacrylic acid, and acrylic acid is particularly preferable.

  The content ratio of the repeating unit derived from the unsaturated carboxylic acid in 100 parts by mass of the fluorine-containing polymer particles is preferably 1 to 10 parts by mass, and more preferably 2.5 to 7.5 parts by mass. preferable.

<Other unsaturated monomers>
In addition to the above-mentioned repeating units, the fluorine-containing polymer particles may further contain repeating units derived from other unsaturated monomers copolymerizable therewith.

  As such an unsaturated monomer, for example, an unsaturated carboxylic acid ester (excluding those corresponding to the compound having two or more polymerizable unsaturated groups and the monomer having a fluorine atom), Examples include α, β-unsaturated nitrile compounds, aromatic vinyl compounds (excluding those corresponding to the compounds having two or more polymerizable unsaturated groups) and other monomers.

  Specific examples of the α, β-unsaturated nitrile compound include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethylacrylonitrile, vinylidene cyanide, etc., and use one or more selected from these. Can do. Among these, at least one selected from the group consisting of acrylonitrile and methacrylonitrile is preferable, and acrylonitrile is particularly preferable.

  Other monomers include alkyl amides of ethylenically unsaturated carboxylic acids such as (meth) acrylamide and N-methylol acrylamide; carboxylic acid vinyl esters such as vinyl acetate and vinyl propionate; acids of ethylenically unsaturated dicarboxylic acids Monoalkyl ester; Monoamide; Aminoalkylamide of ethylenically unsaturated carboxylic acid such as aminoethylacrylamide, dimethylaminomethylmethacrylamide, methylaminopropylmethacrylamide, etc .; Vinylsulfonic acid, styrenesulfonic acid, allylsulfonic acid, sulfone Ethyl methacrylate, sulfopropyl methacrylate, sulfobutyl methacrylate, 2-acrylamido-2-methylpropanesulfonic acid, 2-hydroxy-3-acrylamidopropanesulfonic acid, 3-a Can be exemplified compounds having a sulfonic acid group such as a proxy-2-hydroxypropane sulfonic acid, may be used one or more selected from these.

  Specific examples of the unsaturated carboxylic acid ester and the aromatic vinyl compound include the same compounds as those exemplified in the diene polymer particles described later.

<Aspects of fluorinated polymer particles>
Specific embodiments of the fluorine-containing polymer particles include (1) copolymer particles obtained by synthesizing polymer particles (A1) having a repeating unit derived from a monomer having a fluorine atom by one-step polymerization. And (2) composite particles having a polymer X having a repeating unit derived from a monomer having a fluorine atom and a polymer Y having a repeating unit derived from an unsaturated carboxylic acid. Among these, from the viewpoint of excellent oxidation resistance, composite particles are preferable, and the composite particles are more preferably polymer alloy particles.

  “Polymer alloy” is a “generic name for multi-component polymers obtained by mixing or chemical bonding of two or more components” according to the definition in “Iwanami Physical and Chemical Dictionary 5th edition. Iwanami Shoten”. “Polymer blends physically mixed with different polymers, block and graft copolymers in which different polymer components are covalently bonded, polymer complexes in which different polymers are associated by intermolecular forces, An entangled IPN (Interpenetrating Polymer Network, etc.) ”. However, the polymer alloy as a polymer contained in the composition for an electricity storage device of the present invention is a polymer composed of IPN among “a polymer alloy in which different types of polymer components are not bonded by a covalent bond”.

The polymer X constituting the polymer alloy particles is excellent in electrolyte permeability and liquid retention, and the hard segment of the crystalline resin is aggregated to form a pseudo-crosslink such as C—H—FC in the main chain. It is thought that the point is given. Only such polymer X is mixed with polymer particles (A1),
When used for a protective film of an electricity storage device, the permeability, liquid retention and oxidation resistance of the electrolytic solution are good, but the adhesion and flexibility tend to be insufficient. As a result, the polymer particles (A1) in the protective film cannot be sufficiently bound, and the protective film becomes inhomogeneous, such as the polymer particles (A1) being peeled off. A low power storage device cannot be obtained. On the other hand, although the polymer Y constituting the polymer alloy particles is excellent in adhesion and flexibility, it tends to have low oxidation resistance. When this is used alone as a protective film for an electricity storage device, charge / discharge is performed. Therefore, it is impossible to obtain an electricity storage device having a low rate of increase in resistance.

  However, by using polymer alloy particles containing the polymer X and the polymer Y, the permeability, liquid retention and oxidation resistance, and adhesion and flexibility of the electrolyte can be expressed at the same time. It is possible to manufacture an electricity storage device with a low increase rate. In addition, when a polymer alloy particle consists only of the polymer X and the polymer Y, since oxidation resistance can be improved more, it is preferable.

  Such polymer alloy particles preferably have only one endothermic peak in the temperature range of −50 to 250 ° C. when measured by differential scanning calorimetry (DSC) in accordance with JIS K7121. The temperature of this endothermic peak is more preferably in the range of −30 to + 80 ° C.

  The polymer X constituting the polymer alloy particle generally has an endothermic peak (melting temperature) at −50 to 250 ° C. when it exists alone. In addition, the polymer Y constituting the polymer alloy particles generally has an endothermic peak (glass transition temperature) different from that of the polymer X. For this reason, in the polymer particles (A1), when the polymer X and the polymer Y are present in phase separation as in, for example, a core-shell structure, there are two endothermic peaks in the temperature range of −50 to 250 ° C. Should be observed. From this, when there is only one endothermic peak in the temperature range of −50 to 250 ° C., it can be estimated that the polymer particles (A1) are polymer alloy particles.

  Furthermore, when the temperature of only one endothermic peak of the polymer particles (A1) which are polymer alloy particles is in the range of −30 to + 80 ° C., the polymer particles (A1) have good flexibility and adhesiveness. Therefore, it is preferable because the adhesion can be further improved.

  The polymer X may further include a repeating unit derived from another unsaturated monomer in addition to the repeating unit derived from the monomer having a fluorine atom. Here, as another unsaturated monomer, the above-exemplified unsaturated carboxylic acid, unsaturated carboxylic acid ester, α, β-unsaturated nitrile compound, and other monomers can be used.

  The content ratio of the repeating unit derived from the monomer having a fluorine atom in 100 parts by mass of the polymer X is preferably 80 parts by mass or more, and more preferably 90 parts by mass or more. In such a case, the monomer having a fluorine atom is preferably at least one selected from the group consisting of vinylidene fluoride, ethylene tetrafluoride and propylene hexafluoride.

The more preferable aspect of the polymer X is as follows. That is, the content ratio of the repeating unit derived from vinylidene fluoride in 100 parts by mass of the polymer X is preferably 50 to 99 parts by mass, more preferably 80 to 98 parts by mass; the repetition derived from ethylene tetrafluoride. The content of the unit is preferably 50 parts by mass or less, more preferably 1 to 30 parts by mass, particularly preferably 2 to 20 parts by mass; and the content of the repeating unit derived from propylene hexafluoride. Is preferably 50 parts by mass or less, more preferably 1 to 30 parts by mass, and particularly preferably 2 to 25 parts by mass. The polymer X is most preferably composed of only a repeating unit derived from at least one selected from the group consisting of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene.

  On the other hand, the polymer Y may further have a repeating unit derived from another unsaturated monomer in addition to the repeating unit derived from the unsaturated carboxylic acid. Here, as the other unsaturated monomer, the unsaturated carboxylic acid ester, α, β-unsaturated nitrile compound and other monomers exemplified above can be used.

  The content ratio of the repeating unit derived from the unsaturated carboxylic acid in 100 parts by mass of the polymer Y is preferably 2 to 20 parts by mass, and more preferably 3 to 15 parts by mass.

  As long as the polymer alloy particles have the above-described configuration, the synthesis method is not particularly limited. For example, the polymer alloy particles can be easily synthesized by a known emulsion polymerization step or an appropriate combination thereof.

  For example, first, a polymer X having a repeating unit derived from a monomer having a fluorine atom is synthesized by a known method, and then a monomer for constituting the polymer Y is added to the polymer X to obtain a polymer. A method of synthesizing a polymer Y by sufficiently absorbing the monomer in the stitch structure of the polymer particles X and then polymerizing the monomer absorbed in the stitch structure of the polymer X Polymer alloy particles can be easily produced. When polymer alloy particles are produced by such a method, it is essential that the polymer X sufficiently absorbs the monomer of the polymer Y. When the absorption temperature is too low or the absorption time is too short, only a core-shell type polymer or a part of the surface layer becomes a polymer having an IPN type structure, and the polymer alloy particles in the present invention cannot be obtained. There are many. However, if the absorption temperature is too high, the pressure of the polymerization system becomes too high, which is disadvantageous from the viewpoint of reaction system handling and reaction control, and even if the absorption time is excessively long, further advantageous results are not obtained. .

  From the above viewpoint, the absorption temperature is preferably 30 to 100 ° C, more preferably 40 to 80 ° C, and the absorption time is preferably 1 to 12 hours, and 2 to 8 hours. It is more preferable. At this time, it is preferable to lengthen the absorption time when the absorption temperature is low, and a short absorption time is sufficient when the absorption temperature is high. Conditions under which the value obtained by multiplying the absorption temperature (° C.) and the absorption time (h) is approximately 120 to 300 (° C. · h), preferably 150 to 250 (° C. · h) are appropriate.

  The operation of absorbing the monomer of the polymer Y in the stitch structure of the polymer X is preferably performed in a known medium used for emulsion polymerization, for example, in water.

  The content ratio of the polymer X in 100 parts by mass of the polymer alloy particles is preferably 5 to 50 parts by mass, more preferably 15 to 40 parts by mass, and particularly preferably 20 to 30 parts by mass. When the polymer alloy particles contain the polymer X in the above range, the balance between the permeability, liquid retention and oxidation resistance of the electrolytic solution, and adhesion is improved. Further, when the polymer Y in which the content ratio of the repeating unit derived from each monomer is in the above preferable range is used, the polymer alloy particles contain the polymer X in the above range, so that the polymer alloy It becomes possible to set the content ratio of each repeating unit in the whole particle within the above-mentioned preferable range, and this makes the ethylene carbonate (EC) / diethyl carbonate (DEC) insoluble content an appropriate value. The rate of increase in resistance is sufficiently low.

1.1.1.2. Diene polymer particles <conjugated diene compound>
The diene polymer particles contain a repeating unit derived from a conjugated diene compound. Specific examples of the conjugated diene compound include 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene and the like. It can be one or more selected from these. Among these, 1,3-butadiene is particularly preferable.

  The content ratio of the repeating unit derived from the conjugated diene compound in 100 parts by mass of the diene polymer particles is preferably 30 to 60 parts by mass, and more preferably 40 to 55 parts by mass. When the content ratio of the repeating unit derived from the conjugated diene compound is within the above range, it is preferable because appropriate flexibility can be imparted and the binding property between the polymer particles becomes good.

<Aromatic vinyl compound>
The diene polymer particles preferably contain a repeating unit derived from an aromatic vinyl compound. When the slurry for electrical storage devices contains a conductivity-imparting agent, the affinity for this can be made better.

  Specific examples of the aromatic vinyl compound include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, chlorostyrene, and the like, and can be one or more selected from these. Among the above, the aromatic vinyl compound is particularly preferably styrene.

  The content ratio of the repeating unit derived from the aromatic vinyl compound in 100 parts by mass of the diene polymer particles is preferably 10 to 60 parts by mass, and more preferably 15 to 50 parts by mass. When the content ratio of the repeating unit derived from the aromatic vinyl compound is in the above range, the polymer particles have an appropriate binding property to graphite used as an active material. In addition, the obtained electrode layer has excellent flexibility and binding property to the current collector.

<Unsaturated carboxylic acid ester>
The diene polymer particles preferably contain a repeating unit derived from an unsaturated carboxylic acid ester. The diene polymer particles have repeating units derived from unsaturated carboxylic acid esters, thereby improving the affinity with the electrolyte and suppressing the increase in internal resistance due to the binder becoming an electrical resistance component in the electricity storage device. In addition, it is possible to prevent a decrease in binding property due to excessive absorption of the electrolytic solution.

As the unsaturated carboxylic acid ester, a (meth) acrylic acid ester can be preferably used. Examples thereof include an alkyl ester of (meth) acrylic acid and a cycloalkyl ester of (meth) acrylic acid. The alkyl ester of (meth) acrylic acid is preferably an alkyl ester of (meth) acrylic acid having an alkyl group having 1 to 10 carbon atoms, such as methyl (meth) acrylate, ethyl (meth) acrylate, (meth N-propyl acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, n-amyl (meth) acrylate, i- (meth) acrylate Examples include amyl, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, nonyl (meth) acrylate, and decyl (meth) acrylate. Examples of the cycloalkyl ester of (meth) acrylic acid include cyclohexyl (meth) acrylate. The unsaturated carboxylic acid ester exemplified above may be used alone or in combination of two or more. Among these, it is preferable that it is an alkyl ester of (meth) acrylic acid, from (meth) acrylic acid methyl, (meth) acrylic acid ethyl, (meth) acrylic acid n-butyl, and (meth) acrylic acid 2-ethylhexyl. It is more preferable to use one or more selected.

  The content ratio of the repeating unit derived from the unsaturated carboxylic acid ester in 100 parts by mass of the diene polymer particles is preferably 5 to 40 parts by mass, and more preferably 10 to 30 parts by mass. When the content ratio of the repeating unit derived from the unsaturated carboxylic acid ester is in the above range, the resulting diene polymer particles have an appropriate affinity with the electrolytic solution, and the binder is an electric resistance component in the electricity storage device. It is possible to prevent an increase in internal resistance due to becoming, and to prevent a decrease in binding property due to excessive absorption of the electrolytic solution.

<Unsaturated carboxylic acid>
The diene polymer particles preferably contain a repeating unit derived from an unsaturated carboxylic acid. When the diene polymer particles have a repeating unit derived from an unsaturated carboxylic acid, the stability of the slurry for an electricity storage device using the composition for an electricity storage device according to this embodiment is improved.

  Specific examples of the unsaturated carboxylic acid include unsaturated carboxylic acids similar to those exemplified for the fluorine-containing polymer particles.

  The content ratio of the repeating unit derived from the unsaturated carboxylic acid in 100 parts by mass of the diene polymer particles is preferably 15 parts by mass or less, and more preferably 0.3 to 10 parts by mass. When the content ratio of the repeating unit derived from the unsaturated carboxylic acid is in the above range, since the dispersion stability of the diene polymer particles is excellent at the time of preparing the slurry for the electricity storage device, aggregates are hardly generated. Further, an increase in slurry viscosity over time can be suppressed.

<Other repeating units>
In addition to the above-mentioned repeating units, the diene polymer particles may further contain repeating units derived from other unsaturated monomers copolymerizable therewith.

  Examples of such unsaturated monomers include fluorine-containing compounds having an ethylenically unsaturated bond such as vinylidene fluoride, tetrafluoroethylene, and hexafluoropropylene; (meth) acrylamide, N-methylolacrylamide, and the like. Alkyl amides of ethylenically unsaturated carboxylic acids; carboxylic acid vinyl esters such as vinyl acetate and vinyl propionate; acid anhydrides of ethylenically unsaturated dicarboxylic acids; monoalkyl esters; monoamides; aminoethylacrylamide, dimethylaminomethylmethacrylamide, Aminoalkylamides of ethylenically unsaturated carboxylic acids such as methylaminopropylmethacrylamide; vinyl sulfonic acid, styrene sulfonic acid, allyl sulfonic acid, sulfoethyl methacrylate, sulfopropyl methacrylate, sulfobutyl methacrylate And compounds having a sulfonic acid group such as a rate, 2-acrylamido-2-methylpropanesulfonic acid, 2-hydroxy-3-acrylamidopropanesulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid, and the like. It can be one or more selected from among the above.

1.1.1.3. Number average particle diameter (Da1) of polymer particles (A1)
The number average particle diameter (Da1) of the polymer particles (A1) is preferably in the range of 20 to 450 nm, more preferably in the range of 30 to 420 nm, and particularly preferably in the range of 50 to 400 nm. .

  When the number average particle diameter (Da1) of the polymer particles (A1) is in the above range, the stability of the composition for an electricity storage device is improved, and the internal resistance is increased even when a protective film is formed on the electrode or separator ( Resistance increase rate) can be kept low.

  The number average particle diameter (Da1) of the polymer particles (A1) is the number of particles when the particle size distribution is measured using a particle size distribution measuring apparatus based on the light scattering method and the particles are accumulated from small particles. This is the value of the particle diameter (D50) at which the cumulative frequency is 50%. Examples of such a particle size distribution measuring apparatus include Coulter LS230, LS100, LS13320 (above, manufactured by Beckman Coulter. Inc), FPAR-1000 (manufactured by Otsuka Electronics Co., Ltd.), and the like. These particle size distribution measuring devices are not intended to evaluate only the primary particles of the polymer particles (A1), but can also evaluate secondary particles formed by aggregation of the primary particles. Therefore, the particle size distribution measured by these particle size distribution measuring devices can be used as an indicator of the dispersion state of the polymer particles (A1) contained in the composition.

1.1.1.4. Endothermic Properties of Polymer Particles (A1) The polymer particles (A1) have one endothermic peak in the temperature range of −50 to + 80 ° C. when differential scanning calorimetry (DSC) is performed according to JIS K7121. It is preferable that only be observed. It is presumed that the endothermic behavior of the polymer particles (A1) correlates with the shape stability of the polymer particles. For this reason, if the endothermic peak of the polymer particles (A1) is within the above temperature range, it can be estimated that the shape stability of the polymer particles becomes good and the formed protective film can have sufficient strength.

1.1.1.5. Production method of polymer particle (A1) When polymer particle (A1) is a fluorine-containing polymer particle, its production, that is, a polymer having a repeating unit derived from a monomer having a fluorine atom is one step. In the case of synthesis by polymerization, the polymerization of the polymer X, and the polymerization of the polymer Y in the presence of the polymer X are the presence of a known polymerization initiator, molecular weight regulator, emulsifier (surfactant), etc., respectively. Can be done below.

  Further, when the polymer particles (A1) are diene polymer particles, they may be prepared by one-stage polymerization, two-stage polymerization or further multistage polymerization, and known polymerization initiators in the respective polymerizations. , Molecular weight regulators, emulsifiers (surfactants) and the like.

  Examples of the polymerization initiator include water-soluble polymerization initiators such as sodium persulfate, potassium persulfate, and ammonium persulfate; oil-soluble polymerization such as benzoyl peroxide, lauryl peroxide, and 2,2′-azobisisobutyronitrile. Initiators: Redox polymerization initiators composed of a combination of a reducing agent such as sodium bisulfite, iron (II) salt, tertiary amine and the like, and an oxidizing agent such as persulfate and organic peroxide. . These polymerization initiators can be used singly or in combination of two or more. The use ratio of the polymerization initiator is preferably 0.3 to 3 parts by mass with respect to 100 parts by mass in total of the monomers used.

  Examples of the molecular weight regulator include halogenated hydrocarbons such as chloroform and carbon tetrachloride; mercaptan compounds such as n-hexyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-dotezyl mercaptan, and thioglycolic acid; dimethyl Examples thereof include xanthogen compounds such as xanthogen disulfide and diisopropylxanthogen disulfide; other molecular weight regulators such as terpinolene and α-methylstyrene dimer. These molecular weight regulators can be used singly or in combination of two or more. The use ratio of the molecular weight regulator is preferably 5 parts by mass or less with respect to 100 parts by mass in total of the monomers used.

  Examples of the emulsifier include an anionic surfactant, a nonionic surfactant, an amphoteric surfactant, and a fluorosurfactant.

Examples of the anionic surfactant include sulfates of higher alcohols, alkylbenzene sulfonates, aliphatic sulfonates, sulfates of polyethylene glycol alkyl ethers, etc .; examples of the nonionic surfactants include polyethylene glycol Examples thereof include alkyl esters, alkyl ethers of polyethylene glycol, alkyl phenyl ethers of polyethylene glycol, and the like.

  As the amphoteric surfactant, for example, the anion portion is composed of a carboxylate salt, a sulfate ester salt, a sulfonate salt or a phosphate ester salt, and the cation portion is composed of an amine salt, a quaternary ammonium salt or the like. Things can be mentioned. Specific examples of such amphoteric surfactants include betaine compounds such as lauryl betaine and stearyl betaine; surface activity of amino acid types such as lauryl-β-alanine, lauryl di (aminoethyl) glycine, octyldi (aminoethyl) glycine, and the like. An agent can be mentioned.

  Examples of the fluorosurfactant include fluorobutyl sulfonate, phosphoric acid ester having a fluoroalkyl group, carboxylate having a fluoroalkyl group, and a fluoroalkylethylene oxide adduct. Examples of such commercially available fluorosurfactants include F-top EF301, EF303, EF352 (above, manufactured by Tochem Products Co., Ltd.); Megafac F171, F172, F173 (above, manufactured by DIC Corporation); FC430, FC431 (above, manufactured by Sumitomo 3M Limited); Asahi Guard AG710, Surflon S-382, S-382, SC101, SC102, SC103, SC104, SC105, SC106, Surfinol E1004, KH-10, KH-20, KH-30, KH-40 (above, manufactured by Asahi Glass Co., Ltd.); Footents 250, 251, 222F, FTX-218 (above, manufactured by Neos Co., Ltd.), and the like. As an emulsifier, the 1 type (s) or 2 or more types selected from the above can be used.

  The use ratio of the emulsifier is preferably 0.01 to 10 parts by mass and more preferably 0.02 to 5 parts by mass with respect to 100 parts by mass in total of the monomers used.

  The emulsion polymerization is preferably carried out in a suitable aqueous medium, particularly preferably in water. The total content of the monomers in the aqueous medium can be 10 to 50% by mass, and preferably 20 to 40% by mass.

  The conditions for emulsion polymerization are preferably a polymerization time of 2 to 24 hours at a polymerization temperature of 40 to 85 ° C, and more preferably a polymerization time of 3 to 20 hours at a polymerization temperature of 50 to 80 ° C.

1.1.2. Polymer particles (A2)
In the composition for an electricity storage device according to this embodiment, as polymer particles (A), a repeating unit derived from a compound having two or more polymerizable unsaturated groups in 100 parts by mass is 20 parts by mass or more and 100 parts by mass or less. You may contain the polymer particle (A2) to contain.

  The content ratio of the repeating unit derived from the compound having two or more polymerizable unsaturated groups in 100 parts by mass of the polymer particles (A2) is 20 to 100 parts by mass, preferably 50 parts by mass or more, more preferably. Is 80 parts by mass or more, particularly preferably 90 parts by mass or more. When the content of the repeating unit derived from the compound having two or more polymerizable unsaturated groups is within the above range, the heat resistance, solvent resistance, and short circuit caused by dendrites of the protective film prepared from the composition for the electricity storage device are prevented. This is preferable because the function to improve is improved. Furthermore, the composition for electrical storage devices according to the present embodiment can improve the toughness of the protective film formed by containing the polymer particles (A2).

  Hereinafter, the monomer constituting the repeating unit contained in the polymer particle (A2), the mode of the polymer particle (A2), the production method, and the like will be described in detail.

1.1.2.1. Monomer constituting repeating unit contained in polymer particle (A2) <compound having two or more polymerizable unsaturated groups>
As the compound having two or more polymerizable unsaturated groups, the compound exemplified in the polymer particle (A1) can be used, and the polyfunctional (meth) acrylic acid ester and aromatic polyfunctional vinyl described above are used. At least one selected from the group consisting of compounds can be preferably used. Among these, aromatic divinyl compounds are more preferable, and divinylbenzene is particularly preferable. When the polymer particle (A1) has a repeating unit derived from a compound having two or more polymerizable unsaturated groups, the polymer particle (A2) has the same polymerizable unsaturated group as the polymer particle (A1). It is preferable to have a repeating unit derived from a compound having two or more.

  When the polymer particles (A2) contain a repeating unit derived from divinylbenzene, the content ratio of divinylbenzene is preferably 20 to 100% by mass, more preferably 50 to 100% by mass, particularly with respect to the total monomers. Preferably it is 80-100 mass%. When the content ratio of divinylbenzene is less than 20% by mass, the resulting polymer particles (A2) may be inferior in terms of heat resistance, electrolytic solution resistance, and the like.

<Other unsaturated monomers>
The polymer particle (A2) further includes a repeating unit derived from a compound having two or more polymerizable unsaturated groups, and a repeating unit derived from another unsaturated monomer copolymerizable therewith. It may be.

  Examples of such unsaturated monomers include unsaturated carboxylic acid esters (excluding compounds having two or more polymerizable unsaturated groups) described in the above polymer particles (A1), aromatic vinyl compounds ( However, compounds having two or more polymerizable unsaturated groups are excluded.), Unsaturated carboxylic acids, α, β-unsaturated nitrile compounds, and other unsaturated monomers. In addition, the polymer particle (A2) includes at least a repeating unit derived from a compound having two or more polymerizable unsaturated groups, a repeating unit derived from an unsaturated carboxylic acid ester, and a repeating unit derived from an aromatic vinyl compound. It is preferable to have one.

  The content ratio of the repeating unit derived from the unsaturated carboxylic acid ester in 100 parts by mass of the polymer particles (A2) is preferably 5 to 80 parts by mass, and more preferably 10 to 75 parts by mass.

  The content ratio of the repeating unit derived from the aromatic vinyl compound in 100 parts by mass of the polymer particles (A2) is preferably 5 to 85 parts by mass, and more preferably 10 to 80 parts by mass.

1.1.2.2. Number average particle diameter (Da2) of polymer particles (A2)
The number average particle diameter (Da2) of the polymer particles (A2) is preferably in the range of 100 to 3000 nm, and more preferably in the range of 100 to 1500 nm. The number average particle diameter (Da2) of the polymer particles (A2) is preferably larger than the average pore diameter of the separator that is a porous film. Thereby, the damage to a separator can be reduced and it can prevent that a polymer particle (A2) is clogged with the microporous of a separator.

  The number average particle diameter (Da2) of the polymer particles (A2) can be measured by the same method as that for the polymer particles (A1) described above.

  The particle size ratio (Da2 / Da1) between the number average particle size (Da1) of the polymer particles (A1) and the number average particle size (Da2) of the polymer particles (A2) is preferably 1-30. . When the value of the particle size ratio (Da2 / Da1) is within the above range, when the protective film is formed by coating and drying the composition for an electricity storage device, the polymer particle (A2) is overlapped at the contact point. The coalesced particles (A1) are easy to gather, and the binding force between the particles is improved, which is preferable from the viewpoint of maintaining the shape of the protective film.

1.1.2.3. Endothermic characteristics of polymer particles (A2) When polymer particles (A2) are measured by differential scanning calorimetry (DSC) in accordance with JIS K7121, no endothermic peak is observed within the range of -50 ° C to + 300 ° C. preferable. This indicates that the polymer particles (A2) are crosslinked with a compound having two or more polymerizable unsaturated groups. Thereby, heat resistance and intensity | strength can be provided to the protective film obtained from the composition for electrical storage devices.

1.1.2.4. Embodiment of Polymer Particle (A2) The polymer particle (A2) is preferably a particle having one or more pores therein. When the polymer particles (A2) have one or more pores therein, the electrolyte solution penetrability and liquid retention of the protective film obtained can be improved, and good charge / discharge characteristics can be exhibited. The particle structure may be, for example, a hollow structure having pores inside the particle, or a core-shell type structure having a plurality of pores from the surface of the particle to the inside (core). Also good.

  When the polymer particles (A2) have one or more pores therein, the volume porosity is preferably 1% to 80%, more preferably 2% to 70%, and more preferably 5% Particularly preferred is ˜60%. When the volumetric porosity is in this range, it is possible to achieve both the permeability of the electrolytic solution of the protective film obtained and the liquid retention and toughness improvement.

The volumetric porosity of the polymer particles (A2) was determined by observing the polymer particles (A2) with an electron microscope (manufactured by Hitachi High-Technologies Corporation, Hitachi transmission electron microscope H-7650) and randomly extracting 100 particles. The average particle diameter and particle inner diameter of the particles can be measured and calculated by the following formula (5).
Volume porosity (%) = ((particle inner diameter) ³ / (average particle diameter) ³ ) × 100 (5)

1.1.2.5. Production method of polymer particles (A2) The polymer particles (A2) contained in the composition for an electricity storage device according to the present embodiment are not particularly limited as long as the polymer particles (A2) have the above-described configuration. Specifically, it is preferable to use methods such as emulsion polymerization, seeding emulsion polymerization, suspension polymerization, seeding suspension polymerization, and solution precipitation polymerization. Of these, emulsion polymerization and seeding emulsion polymerization are preferred. Of these, seeding emulsion polymerization is particularly preferred because the particle size distribution can be easily controlled uniformly.

  When the polymer particles (A2) have a hollow structure, the methods described in JP-A No. 2002-30113, JP-A No. 2009-120784, and JP-A No. 62-127336 are used. In the case of a core-shell type, it can be manufactured according to the method described in JP-A-4-98201.

1.2. Metal complex salt (B)
The composition for an electricity storage device according to the present embodiment contains a metal complex salt (B). The metal complex salt (B) forms a metal cross-linking structure by chelating or ligand exchange with the ionic functional group of the polymer particle (A) described above, and can protect the separator from thermal shrinkage. It is presumed that a film can be produced. Similarly, it is presumed that an electrode for an electricity storage device having a high elastic modulus can be produced.

  In order to further improve the stability of the composition for an electricity storage device for producing a protective film, such a metal complex salt (B) is coordinated for ligand exchange in the preparation process for the composition for an electricity storage device. You may add as a metal salt which has a child, and may add as a chelate compound which has a low molecular weight ligand.

The metal complex salt (B) is preferably a metal complex salt represented by the following general formula (6).
R ⁷ sM (6)
(R ⁷ has a chelating agent, ammonia, ammonium ion, hydroxide ion, carbonate ion, an alkoxy group which may have a substituent having 2 to 10 carbon atoms, and a substituent having 6 to 20 carbon atoms. And represents at least one selected from the group consisting of phenoxy groups which may be present, M represents a metal atom, and s represents the valence of the metal M.)

Examples of the chelating agent for R ⁷ include β-diketone, β-ketoester, and the like. Specifically, acetylacetone, methyl acetoacetate, ethyl acetoacetate, acetoacetate-n-propyl, acetoacetate-i-propyl, Acetoacetate-n-butyl, acetoacetate-sec-butyl, acetoacetate-t-butyl, 2,4-hexane-dione, 2,4-heptane-dione, 3,5-heptane-dione, 2,4-octane -Dione, 2,4-nonane-dione, 5-methylhexane-dione and the like can be mentioned.

Examples of the alkoxy group which may have a substituent of 2 to 10 carbon atoms for R ⁷ include hydrocarbons such as isopropoxy, amines such as triethanolamine and trimethanolamine, and hydroxy acids such as lactic acid. be able to.

  The metal atom of M is preferably a divalent or higher polyvalent metal ion, more preferably a group 4, 12 or 13 metal ion of the periodic table, titanium, zirconium, aluminum. Particularly preferred is at least one metal ion selected from the group consisting of tin, and zinc.

Specific examples of the metal complex represented by the general formula (6) include triethoxy mono (acetylacetonato) titanium, tri-n-propoxy mono (acetylacetonato) titanium, tri-i-propoxy mono ( Acetylacetonato) titanium, tri-n-butoxy mono (acetylacetonato) titanium, tri-sec-butoxy mono (acetylacetonato) titanium, tri-t-butoxy mono (acetylacetonato) titanium, diethoxy Bis (acetylacetonato) titanium, di-n-propoxy bis (acetylacetonato) titanium, di-i-propoxy bis (acetylacetonato) titanium, di-n-butoxy bis (acetylacetonato) titanium, Di-sec-butoxy bis (acetylacetonato) titanium, di- -Butoxy bis (acetylacetonato) titanium, monoethoxy tris (acetylacetonato) titanium, mono-n-propoxy tris (acetylacetonato) titanium, mono-i-propoxy tris (acetylacetonato) titanium, Mono-n-butoxy-tris (acetylacetonato) titanium, mono-sec-butoxy-tris (acetylacetonato) titanium, mono-t-butoxy-tris (acetylacetonato) titanium, tetrakis (acetylacetonato) titanium, Triethoxy mono (ethyl acetoacetate) titanium, tri-n-propoxy mono (ethyl acetoacetate) titanium, tri-i-propoxy mono (ethyl acetoacetate) titanium, tri-n-butoxy mono (ethyl acetoacetate) H Tri-sec-butoxy mono (ethyl acetoacetate) titanium, tri-t-butoxy mono (ethyl acetoacetate) titanium, diethoxy bis (ethyl acetoacetate) titanium, di-n-propoxy bis (ethyl aceto) Acetate) titanium, di-i-propoxy bis (ethyl acetoacetate) titanium, di-n-butoxy bis (ethyl acetoacetate) titanium, di-sec-butoxy bis (ethyl acetoacetate) titanium, di-t- Butoxy bis (ethyl acetoacetate) titanium, monoethoxy tris (ethyl acetoacetate) titanium, mono-n-propoxy tris (ethyl acetoacetate) titanium, mono-i-propoxy tris (ethyl acetoacetate) titanium, mono -N-Butoxy Tris (Ethyl acetoacetate) titanium, mono-sec-butoxy tris (ethyl acetoacetate) titanium, mono-t-butoxy tris (ethyl acetoacetate) titanium, tetrakis (ethyl acetoacetate) titanium, mono (acetylacetonate) tris (Ethyl acetoacetate) titanium, bis (acetylacetonate) bis (ethylacetoacetate) titanium, tris (acetylacetonate) mono (ethylacetoacetate) titanium, titanium octylene glycolate, titanium lactate, titanium diisopropoxybis ( Titanium chelate compounds such as triethanolaminate), di-i-propoxybis (triethanolamate) titanium, titanium lactate;

  Triethoxy mono (acetylacetonato) zirconium, tri-n-propoxy mono (acetylacetonato) zirconium, tri-i-propoxy mono (acetylacetonato) zirconium, tri-n-butoxy mono (acetylacetonate) Zirconium, tri-sec-butoxy mono (acetylacetonato) zirconium, tri-t-butoxy mono (acetylacetonato) zirconium, diethoxybis (acetylacetonato) zirconium, di-n-propoxybis (acetylacetate) Nato) zirconium, di-i-propoxy bis (acetylacetonato) zirconium, di-n-butoxy bis (acetylacetonato) zirconium, di-sec-butoxy bis (acetylacetonato) ziru Ni, di-t-butoxy bis (acetylacetonato) zirconium, monoethoxy tris (acetylacetonato) zirconium, mono-n-propoxytris (acetylacetonato) zirconium, mono-i-propoxytris (acetyl) Acetonato) zirconium, mono-n-butoxy-tris (acetylacetonato) zirconium, mono-sec-butoxy-tris (acetylacetonato) zirconium, mono-t-butoxy-tris (acetylacetonato) zirconium, tetrakis (acetyl) Acetonato) zirconium, triethoxy mono (ethyl acetoacetate) zirconium, tri-n-propoxy mono (ethyl acetoacetate) zirconium, tri-i-propoxy mono (ethyl acetate) Acetate) zirconium, tri-n-butoxy mono (ethyl acetoacetate) zirconium, tri-sec-butoxy mono (ethyl acetoacetate) zirconium, tri-t-butoxy mono (ethyl acetoacetate) zirconium, diethoxy bis ( Ethyl acetoacetate) zirconium, di-n-propoxy bis (ethyl acetoacetate) zirconium, di-i-propoxy bis (ethyl acetoacetate) zirconium, di-n-butoxy bis (ethyl acetoacetate) zirconium, di- sec-butoxy bis (ethyl acetoacetate) zirconium, di-t-butoxy bis (ethyl acetoacetate) zirconium, monoethoxy tris (ethyl acetoacetate) zirconium, mono-n- Propoxy tris (ethyl acetoacetate) zirconium, mono-i-propoxy tris (ethyl acetoacetate) zirconium, mono-n-butoxy tris (ethyl acetoacetate) zirconium, mono-sec-butoxy tris (ethyl acetoacetate) Zirconium, mono-t-butoxy-tris (ethylacetoacetate) zirconium, tetrakis (ethylacetoacetate) zirconium, mono (acetylacetonato) tris (ethylacetoacetate) zirconium, bis (acetylacetonato) bis (ethylacetoacetate) Zirconium compounds such as zirconium, tris (acetylacetonate) mono (ethylacetoacetate) zirconium, zirconium ammonium carbonate;

  One type or two or more types of aluminum compounds such as tris (acetylacetonate) aluminum and tris (ethylacetoacetate) aluminum; zinc compounds such as zinc ammonium acetate and zinc ammonium carbonate;

  When forming a protective film on the separator surface using the composition for an electricity storage device according to this embodiment, the ionic functional group content of the polymer particles (A) is Ma mol, and the content of the metal complex salt (B) When Mb is Mb mol, it is preferably in the range of Mb / Ma = 0.1-15, more preferably in the range of 0.2-13. When Mb / Ma is in the above range, the ionic functional group of the polymer particle (A) and the metal complex salt (B) form a ligand exchange reaction or an ionic bond, and the polymer particle (A) Bonds firmly in the protective film. As a result, it is possible to more effectively suppress the thermal contraction of the separator when the hole of the separator is closed during the abnormal heat generation of the electricity storage device and the shutdown function is exhibited.

The ionic functional group amount Ma (mmol) of the polymer particles (A) can be calculated by the following calculation formula.
-Amount of ionic functional group in 1 g of each polymer particle (mol / 1 g) = (mass part of structural unit having ionic functional group (g) ÷ ion when the total of the structural units of each polymer particle is 100 g) Molecular weight of structural unit having a functional group (g / mol)) ÷ 100
Ma (mmol) = (Amount of ionic functional group in 1 g of each polymer particle (mol / 1 g) × mass part of each polymer particle (g)) × 1000

The content Mb (mmol) of the metal complex salt (B) can be calculated by the following calculation formula.
Mb (mmol) = mass part of metal compound (g) ÷ molecular weight of metal compound (g / mol) × 1000

  When forming a protective film on the separator surface using the composition for an electricity storage device according to the present embodiment, the content of the metal complex salt (B) is such that the polymer particles (A), a water-soluble polymer (D) described later, and inorganic It is preferably 0.5 to 15 parts by mass and more preferably 0.9 to 10 parts by mass with respect to 100 parts by mass in total of the filler (E).

  When producing an electricity storage device electrode using the composition for an electricity storage device according to this embodiment, the amount of the ionic functional group of the polymer particles (A) is Ma mol, and the content of the metal complex salt (B) is Mb. In terms of mole, Mb / Ma is preferably in the range of 0.1 to 15, more preferably in the range of 0.2 to 13. When Mb / Ma is in the above range, the ionic functional group of the polymer particle (A) and the metal complex salt (B) form a ligand exchange reaction or an ionic bond, so that the polymer particle (A) Improves the adhesion of the active material layer. As a result, an electricity storage device electrode having excellent adhesion and charge / discharge characteristics can be obtained.

  When producing an electrical storage device electrode using the electrical storage device composition according to the present embodiment, the content of the metal complex salt (B) is 0.01 to 5 with respect to a total of 100 parts by mass of the active material (F). It is preferable that it is a mass part, and it is more preferable that it is 0.5-4 mass parts.

1.3. Liquid medium (C)
The composition for an electricity storage device according to this embodiment further contains a liquid medium (C). The liquid medium (C) is preferably an aqueous medium containing water. This aqueous medium can contain a small amount of non-aqueous medium in addition to water. Examples of such non-aqueous media include amide compounds, hydrocarbons, alcohols, ketones, esters, amine compounds, lactones, sulfoxides, sulfone compounds, and the like, and one or more selected from these are used. can do. The content ratio of such a non-aqueous medium is preferably 10% by mass or less, and more preferably 5% by mass or less, with respect to the total amount of the aqueous medium. The aqueous medium is most preferably composed only of water without containing a non-aqueous medium.

  The composition for an electricity storage device according to the present embodiment uses an aqueous medium as the liquid medium (C), and preferably contains no non-aqueous medium other than water, so that it has a low degree of adverse effects on the environment. The safety against is increased.

1.4. Other components 1.4.1. Water-soluble polymer (D)
The composition for an electricity storage device according to the present embodiment may contain a water-soluble polymer (D) from the viewpoint of improving the coatability and adhesion. A protective film capable of suppressing thermal shrinkage of the separator is produced by forming a metal cross-linking structure by chelating or ligand exchange between the ionic functional group of the water-soluble polymer (D) and the metal complex salt (B). It is speculated that you can. Similarly, it is presumed that an electrode for an electricity storage device having excellent adhesion can be produced.

  Examples of the water-soluble polymer (D) include cellulose compounds such as carboxymethylcellulose, methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, and hydroxyethylcellulose; ammonium salts or alkali metal salts of the above cellulose compounds; poly (meth) acrylic acid, modified poly Polycarboxylic acids such as (meth) acrylic acid; alkali metal salts of the above polycarboxylic acids; polyvinyl alcohol (co) polymers such as polyvinyl alcohol, modified polyvinyl alcohol, and ethylene-vinyl alcohol copolymers; (meth) acrylic acid Saponified products of copolymers of unsaturated carboxylic acids such as maleic acid and fumaric acid with vinyl esters; alternating copolymers of maleic anhydride and isobutylene; ammonium salts of the alternating copolymers or And water-soluble polymers such as alkali metal salts. Among these, particularly preferred water-soluble polymers (D) include alkali metal salts of carboxymethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, alkali metal salts of poly (meth) acrylic acid, and alternating copolymers of maleic anhydride and isobutylene. Alkali metal salts of

  Examples of commercially available water-soluble polymers (D) include CMC 1120, CMC 1150, CMC 2200, CMC 2280, CMC 2450 (manufactured by Daicel Corporation), Metroles SH type, Metroles SE type (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like. Mention may be made of alkali metal salts of carboxymethylcellulose. In addition, examples of commercially available alternating copolymers of maleic anhydride and isobutylene include isoban 06, isoban 10, isoban 18, isoban 110 (above, manufactured by Kuraray Co., Ltd.) and the like.

  When forming a protective film on the separator surface using the composition for an electricity storage device according to the present embodiment, the content of the metal complex salt (B) is Mb mol, and the water-soluble polymer (D) has an ionic functional group. When the amount is Md, it is preferably in the range of Mb / Md = 0.1-15, and more preferably in the range of 0.2-13. When Mb / Md is in the above range, the ionic functional group of the water-soluble polymer (D) and the metal complex salt (B) form a ligand exchange reaction or ionic bond, and the water-soluble polymer (D) Bonds firmly in the protective film. As a result, it is possible to more effectively suppress the thermal contraction of the separator when the hole of the separator is closed during the abnormal heat generation of the electricity storage device and the shutdown function is exhibited.

When producing an electricity storage device electrode using the composition for an electricity storage device according to this embodiment, the content of the metal complex salt (B) is Mb mol, and the amount of the ionic functional group of the water-soluble polymer (D) is When Md is set, Mb / Md is preferably in the range of 0.1 to 15, more preferably in the range of 0.2 to 13. When Mb / Md is within the above range, the ionic functional group of the water-soluble polymer (D) and the metal complex salt form a ligand exchange reaction or an ionic bond, and the water-soluble polymer (D) becomes the active material layer. Improve adhesion. As a result, an electricity storage device electrode having excellent adhesion and charge / discharge characteristics can be obtained.

The amount Md (mmol) of the ionic functional group of the water-soluble polymer (D) can be calculated by the following calculation formula.
Md (mmol) = (Amount of ionic functional group in 1 g of water-soluble polymer (mol / 1 g) × (mass part of water-soluble polymer (g)) × 1000

  When the composition for an electricity storage device according to this embodiment contains a water-soluble polymer (D), the content of the water-soluble polymer (D) is 5% by mass or less based on the total solid content of the composition for an electricity storage device. It is preferable that it is 0.1-3 mass%.

1.4.2. Surfactant The composition for an electricity storage device according to the present embodiment may contain a surfactant from the viewpoint of improving dispersibility and dispersion stability. Examples of the surfactant include those described in “1.1.1.5. Production method of polymer particles (A1)”.

2. Power Storage Device Slurry The power storage device slurry according to the present embodiment contains the above-described power storage device composition. And the above-mentioned composition for electrical storage devices can also be used as a material for forming a protective film for suppressing a short circuit caused by dendrite that occurs in association with charge and discharge, and the ability to bind active materials to each other In addition, it can also be used as a material for producing an electricity storage device electrode (active material layer) having improved adhesion ability between the active material and the current collector and resistance to powder falling. Therefore, a slurry for an electricity storage device for forming a protective film (hereinafter also referred to as “slurry for forming a protective film”) and a slurry for an electricity storage device for forming an active material layer of the electricity storage device electrode (hereinafter referred to as “electric storage device”). It is also referred to as “device electrode slurry”.

2.1. Protective film forming slurry In this specification, “slurry for forming a protective film” is applied to the surface of the electrode and / or separator and then dried to form a protective film on the surface of the electrode and / or separator. Refers to the dispersion used to form. The slurry for forming a protective film according to this embodiment may be composed only of the above-described composition for an electricity storage device, and may further contain inorganic particles. Hereinafter, each component contained in the slurry for forming a protective film according to this embodiment will be described in detail. In addition, about the composition for electrical storage devices, since it is as above-mentioned, description is abbreviate | omitted.

2.1.1. Inorganic filler (E)
The protective film-forming slurry according to this embodiment can improve the toughness of the protective film to be formed by containing the inorganic filler (E). As the inorganic filler (E), at least one kind of particles selected from the group consisting of silica, titanium oxide (titania), aluminum oxide (alumina), zirconium oxide (zirconia), and magnesium oxide (magnesia) is used. preferable. Among these, titanium oxide and aluminum oxide are preferable from the viewpoint of further improving the toughness of the protective film. Further, as the titanium oxide, rutile type titanium oxide is more preferable.

The average particle size of the inorganic filler (E) is preferably 1 μm or less, and more preferably in the range of 0.1 to 0.8 μm. In addition, it is preferable that the average particle diameter of an inorganic filler (E) is larger than the average hole diameter of the separator which is a porous film. Thereby, damage to a separator can be reduced and it can prevent that an inorganic filler (E) is clogged with the microporous of a separator.

  The slurry for forming a protective film according to this embodiment may contain 0.1 to 20 parts by mass of the composition for an electricity storage device described above in terms of solid content with respect to 100 parts by mass of the inorganic filler (E). Preferably, 1 to 10 parts by mass is contained. When the content ratio of the composition for an electricity storage device is 0.1 to 10 parts by mass in terms of solid content, the balance between the toughness of the formed protective film and the lithium ion permeability is improved, and as a result, obtained. The rate of increase in resistance of the electricity storage device can be further reduced.

2.1.2. Other components In the slurry for forming a protective film according to the present embodiment, the materials and addition amounts described in “1.4. Other components” of the composition for an electricity storage device can be used as necessary. .

2.2. “Slurry for electricity storage device electrode” in this specification is used to form an active material layer on the surface of the current collector after being applied to the surface of the current collector and then dried. Refers to a dispersion. The slurry for an electricity storage device electrode according to this embodiment contains the above-described composition for an electricity storage device and an active material. Hereinafter, each component contained in the slurry for an electricity storage device electrode according to the present embodiment will be described in detail. In addition, about the composition for electrical storage devices, since it is as above-mentioned, description is abbreviate | omitted.

2.2.1. Active material (F)
Examples of the active material (F) used in the power storage device electrode slurry according to the present embodiment include carbon materials, silicon materials, oxides containing lithium atoms, lead compounds, tin compounds, arsenic compounds, antimony compounds, and aluminum compounds. And so on.

  Examples of the carbon material include amorphous carbon, graphite, natural graphite, mesocarbon microbeads (MCMB), and pitch-based carbon fibers.

Examples of the silicon material include silicon simple substance, silicon oxide, and silicon alloy. For example, SiC, SiO _x C _y (0 <x ≦ 3, 0 <y ≦ 5), Si ₃ N ₄ , Si oxide complex represented by Si ₂ N ₂ O, SiO _x (0 <x ≦ 2) (for example, materials described in JP-A Nos. 2004-185810 and 2005-259697), A silicon material described in JP-A No. 2004-185810 can be used. The silicon oxide is preferably a silicon oxide represented by the composition formula SiO _x (0 <x <2, preferably 0.1 ≦ x ≦ 1). The silicon alloy is preferably an alloy of silicon and at least one transition metal selected from the group consisting of titanium, zirconium, nickel, copper, iron and molybdenum. These transition metal silicon alloys are preferably used because they have high electronic conductivity and high strength. In addition, since the active material contains these transition metals, the transition metal present on the surface of the active material is oxidized to form an oxide having a hydroxyl group on the surface, so that the binding force with the binder is further improved. preferable. As the silicon alloy, it is more preferable to use a silicon-nickel alloy or a silicon-titanium alloy, and it is particularly preferable to use a silicon-titanium alloy. The silicon content in the silicon alloy is preferably 10 mol% or more, and more preferably 20 to 70 mol%, based on all the metal elements in the alloy. Note that the silicon material may be single crystal, polycrystalline, or amorphous.

Examples of the oxide containing a lithium atom include lithium cobaltate, lithium nickelate, lithium manganate, ternary nickel cobalt lithium manganate, LiFePO ₄ , LiCoPO ₄ , LiMnPO ₄ , Li _0.90 Ti _0.05 Nb. _0.05 Fe _0.
30 Co _0.30 Mn _0.30 PO _{4 and the} like.

Further, the active material exemplified below may be included in the active material layer. Examples of such an active material include a conductive polymer such as polyacene; A _X B _Y O _Z (where A is an alkali metal or transition metal, B is a transition metal such as cobalt, nickel, aluminum, tin, or manganese) At least one selected, O represents an oxygen atom, and X, Y, and Z are 1.10>X> 0.05, 4.00>Y> 0.85, 5.00>Z> 1.5, respectively. The composite metal oxide represented by (2) and other metal oxides are exemplified.

  The slurry for an electricity storage device electrode according to this embodiment can be used when producing either the positive electrode or the negative electrode electricity storage device electrode.

  When producing a positive electrode, it is preferable to use the oxide containing a lithium atom among the active materials illustrated above.

  When producing a negative electrode, it is preferable to use what contained the silicon material among the active materials illustrated above. Since the silicon material has a larger amount of occlusion of lithium per unit weight than other active materials, the active material contains the silicon material, so that the power storage capacity of the obtained power storage device can be increased. The output and energy density of the electricity storage device can be increased. The negative electrode active material is more preferably composed of a mixture of a silicon material and a carbon material. Since the volume change due to charge and discharge is small, the carbon material can reduce the influence of the volume change of the silicon material by using a mixture of the silicon material and the carbon material as the negative electrode active material, The adhesion ability with the active material layer can be further improved. As such a mixture, a carbon-coated silicon material in which a carbon material film is formed on the surface of the silicon material can also be used. By using a carbon-coated silicon material, the effect of volume change associated with charging / discharging of the silicon material can be more effectively mitigated by the carbon material present on the surface, so that the active material layer and the current collector It becomes easy to improve the adhesion ability.

When silicon (Si) is used as an active material, silicon can occlude up to 22 lithium atoms per 5 atoms (5Si + 22Li → Li ₂₂ Si ₅ ). As a result, the theoretical silicon capacity reaches 4200 mAh / g. However, silicon causes a large volume change when occludes lithium. Specifically, the carbon material expands in volume up to about 1.2 times by occluding lithium, whereas the silicon material expands in volume up to about 4.4 times by occluding lithium. For this reason, the silicon material is pulverized by repeated expansion and contraction, peeling from the current collector, and separation of the active materials, and the conductive network inside the active material layer is broken. Therefore, the cycle characteristics are extremely deteriorated in a short time.

  However, in the electricity storage device electrode according to the present embodiment, even when a silicon material is used, good electrical characteristics can be exhibited without causing the above-described problems. This is because the polymer particles (A) can firmly bind the silicon material, and at the same time, the polymer particles (A) expand and contract even if the silicon material undergoes volume expansion due to occlusion of lithium. This is considered to be because the state in which the material is firmly bound can be maintained.

  The content ratio of the silicon material in 100% by mass of the active material is preferably 1% by mass or more, more preferably 1 to 50% by mass, further preferably 5 to 45% by mass. It is especially preferable to set it as -40 mass%.

When a silicon material and a carbon material are used in combination as the active material, the amount of the silicon material used is 4 to 40% by mass in terms of 100% by mass of the active material from the viewpoint of maintaining sufficient binding properties. %, More preferably 5 to 35% by mass, and particularly preferably 5 to 30% by mass. Since the volume expansion of the carbon material relative to the volume expansion of the silicon material due to occlusion of lithium is small when the amount of silicon material used is in the above range, the volume change due to charge / discharge of the active material layer containing these active materials is reduced. The binding between the current collector and the active material layer can be further improved.

  The shape of the active material is preferably granular. The average particle diameter of the active material is preferably 0.1 to 100 μm, and more preferably 1 to 20 μm.

  Here, the average particle diameter of the active material is a volume average particle diameter calculated from a particle size distribution measured by using a particle size distribution measuring apparatus based on a laser diffraction method. Examples of such a laser diffraction particle size distribution measuring apparatus include HORIBA LA-300 series, HORIBA LA-920 series (manufactured by Horiba, Ltd.) and the like. This particle size distribution measuring apparatus does not only evaluate primary particles of the active material, but also evaluates secondary particles formed by aggregation of the primary particles. Therefore, the average particle diameter obtained by the particle size distribution measuring apparatus can be used as an index of the dispersion state of the active material contained in the slurry for the electricity storage device electrode. The average particle diameter of the active material can also be measured by centrifuging the slurry to settle the active material, removing the supernatant, and measuring the precipitated active material by the above method. .

  The use ratio of the active material (F) is preferably such that the content ratio of the polymer particles (A) to 100 parts by mass of the active material is 0.1 to 25 parts by mass, It is more preferable to use it at a ratio of 15 parts by mass. By setting it as such a usage rate, it is possible to produce an electrode that is excellent in adhesiveness and has low electrode resistance and excellent charge / discharge characteristics.

3. The electricity storage device electrode according to the present embodiment includes a current collector and a layer formed by applying and drying the above-mentioned slurry for an electricity storage device electrode on the surface of the current collector. . Such an electricity storage device electrode can be produced by applying the above-mentioned slurry for an electricity storage device electrode on the surface of an appropriate current collector such as a metal foil to form a coating film, and then drying the coating film. . In the electrical storage device electrode thus manufactured, an active material layer containing the above-described polymer particles (A) and an active material, and an optional component added as necessary, is bound on a current collector. It will be. In such an electricity storage device electrode, the ionic functional group of the polymer particle (A) and the metal complex salt (B) form a ligand exchange reaction or an ionic bond, whereby the polymer particle (A) is an active material. Improve layer adhesion. Thereby, while being excellent in the adhesiveness of a collector and an active material layer, the charge / discharge rate characteristic which is one of the electrical characteristics becomes favorable.

  The current collector is not particularly limited as long as it is made of a conductive material. In a lithium ion secondary battery, a current collector made of metal such as iron, copper, aluminum, nickel, and stainless steel is used. In particular, when aluminum is used for the positive electrode and copper is used for the negative electrode, the above-described storage device electrode The effect of the slurry is most apparent. As the current collector in the nickel metal hydride secondary battery, a punching metal, an expanded metal, a wire mesh, a foam metal, a mesh metal fiber sintered body, a metal plated resin plate, or the like is used. The shape and thickness of the current collector are not particularly limited, but it is preferable that the current collector has a sheet shape with a thickness of about 0.001 to 0.5 mm.

There is no particular limitation on the method for applying the slurry for the electricity storage device electrode to the current collector. The coating can be performed by an appropriate method such as a doctor blade method, a dip method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, a dipping method, or a brush coating method. The amount of the electricity storage device electrode slurry applied is not particularly limited, but it is preferable that the thickness of the active material layer formed after removing the liquid medium be 0.005 to 5 mm, 0.01 to 2 mm. It is more preferable to set the amount to be.

  There is no particular limitation on the drying method from the coated film after coating (method for removing water and optionally used non-aqueous medium), for example, drying with hot air, hot air or low-humidity air; vacuum drying; (far) infrared , Drying by irradiation with an electron beam or the like. The drying speed is appropriately set so that the liquid medium can be removed as quickly as possible within a speed range in which the active material layer does not crack due to stress concentration or the active material layer does not peel from the current collector. be able to.

Furthermore, it is preferable to increase the density of the active material layer by pressing the dried active material layer. Examples of the pressing method include a mold press and a roll press. The density of the active material layer after the press, preferably in the 1.6~2.4g / cm ^3, and more preferably to 1.7~2.2g / cm ^3.

4). Hereinafter, preferred embodiments of an electricity storage device according to the present invention will be described in detail with reference to the drawings. An electricity storage device according to an embodiment of the present invention includes a positive electrode, a negative electrode, a protective film disposed between the positive electrode and the negative electrode, and an electrolytic solution, and the protective film is for forming the protective film described above. It is produced using a slurry. Hereinafter, first to third embodiments will be described with reference to the drawings.

4.1. First Embodiment FIG. 1 is a schematic view showing a cross section of an electricity storage device according to a first embodiment. As shown in FIG. 1, the electricity storage device 1 includes a positive electrode 10 in which a positive electrode active material layer 14 is formed on the surface of a positive electrode current collector 12 and a negative electrode 20 in which a negative electrode active material layer 24 is formed on the surface of a negative electrode current collector 22. And a protective film 30 provided between the positive electrode 10 and the negative electrode 20, and an electrolyte solution 40 that fills between the positive electrode 10 and the negative electrode 20. In the electricity storage device 1, no separator is provided between the positive electrode 10 and the negative electrode 20. This is because if the positive electrode 10 and the negative electrode 20 are completely fixed with a solid electrolyte or the like, the positive electrode 10 and the negative electrode 20 do not come into contact with each other to cause a short circuit.

  The positive electrode 10 shown in FIG. 1 is formed so that the positive electrode active material layer 14 is not provided on one surface along the longitudinal direction and the positive electrode current collector 12 is exposed. A layer 14 may be provided. Similarly, the negative electrode 20 shown in FIG. 1 is formed such that the negative electrode active material layer 24 is not provided on one surface along the longitudinal direction and the negative electrode current collector 22 is exposed, A negative electrode active material layer 24 may be provided.

  As the positive electrode current collector 12, for example, a metal foil, an etching metal foil, an expanded metal, or the like can be used. Specific examples of these materials include metals such as aluminum, copper, nickel, tantalum, stainless steel, and titanium, and can be appropriately selected and used according to the type of the target power storage device. For example, when forming the positive electrode of a lithium ion secondary battery, it is preferable to use aluminum among the above as the positive electrode current collector 12. In such a case, the thickness of the positive electrode current collector 12 is preferably 5 to 30 μm, and more preferably 8 to 25 μm.

The positive electrode active material layer 14 includes one or more positive electrode active materials of a positive electrode material that can be doped / dedoped with lithium, and is configured to include a conductivity-imparting agent such as graphite as necessary. . In addition, as a binder, a thickener used for dispersion of a fluorine-containing polymer such as polyvinylidene fluoride or polyfluorinated acrylate or a positive electrode active material, or a styrene butadiene rubber (SBR) or (meth) acrylate copolymer A polymer composition containing a coalescence may be used. These binders may use only 1 type and may mix and use 2 or more types.

  As the negative electrode current collector 22, for example, a metal foil, an etching metal foil, an expanded metal, or the like can be used. Specific examples of these materials include metals such as aluminum, copper, nickel, tantalum, stainless steel, and titanium, and can be appropriately selected and used according to the type of the target power storage device. Of the above, copper is preferably used as the negative electrode current collector 22. In such a case, the thickness of the current collector is preferably 5 to 30 μm, and more preferably 8 to 25 μm.

  The negative electrode active material layer 24 is configured to include any one or two or more negative electrode materials that can be doped / undoped with lithium as a negative electrode active material, and if necessary, a binder similar to the positive electrode It is comprised including.

Note that the above-described active material layer is preferably subjected to press working. Examples of means for performing the press working include a roll press machine, a high-pressure super press machine, a soft calendar, and a 1-ton press machine. The conditions for the press working are appropriately set according to the type of processing machine used and the desired thickness and density of the active material layer. In the case of a lithium ion secondary battery positive electrode, the thickness is preferably 40 to 100 μm and the density is preferably 2.0 to 5.0 g / cm ³ . In the case of a lithium ion secondary battery negative electrode, the thickness is preferably 40 to 100 μm and the density is preferably 1.3 to 1.9 g / cm ³ .

  The protective film 30 is disposed between the positive electrode 10 and the negative electrode 20. 1, the protective film 30 is disposed between the positive electrode 10 and the negative electrode 20 so as to be in contact with the positive electrode active material layer 14, but is disposed so as to be in contact with the negative electrode active material layer 24. May be. The protective film 30 may be disposed as a self-supporting film between the positive electrode 10 and the negative electrode 20 without being in contact with the positive electrode 10 or the negative electrode 20. Thereby, even if it is a case where dendrites precipitate by repeating charging / discharging, since it is guarded by the protective film 30, a short circuit does not occur. Therefore, the function as an electricity storage device can be maintained.

  The protective film 30 can be formed, for example, by applying the above-described protective film-forming slurry to the surface of the positive electrode 10 (or the negative electrode 20) and drying it. For example, a doctor blade method, a reverse roll method, a comma bar method, a gravure method, an air knife method, a die coating method, or the like is applied as a method for applying the protective film forming slurry to the surface of the positive electrode 10 (or the negative electrode 20). Can do. The drying treatment of the coating film is preferably performed in a temperature range of 20 to 250 ° C., more preferably 50 to 150 ° C., preferably for a processing time of 1 to 120 minutes, more preferably 5 to 60 minutes.

  Although the film thickness of the protective film 30 is not specifically limited, It is preferable that it is the range of 0.5-4 micrometers, and it is more preferable that it is the range of 0.5-3 micrometers. When the thickness of the protective film 30 is within the above range, the permeability of the electrolytic solution into the electrode and the liquid retaining property are improved, and an increase in the internal resistance of the electrode can be suppressed.

  The electrolytic solution 40 is appropriately selected and used according to the type of the target power storage device. As the electrolytic solution 40, a solution in which an appropriate electrolyte is dissolved in a solvent is used.

When manufacturing a lithium ion secondary battery, a lithium compound is used as an electrolyte. Specifically, for example _{LiClO 4, LiBF 4, LiI,} LiPF 6, LiCF 3 SO 3, LiAsF 6, LiSbF 6, LiAlCl 4, LiCl, LiBr, LiB (C 2 H 5) 4, LiCH 3 SO 3, LiC _{4 F 9 SO 3, Li (} CF 3 SO 2) can be cited ₂ N or the like. The electrolyte concentration in this case is preferably 0.5 to 3.0 mol / L, more preferably 0.7 to 2.0 mol / L.

  The type and concentration of the electrolyte in the case of manufacturing a lithium ion capacitor are the same as in the case of the lithium ion secondary battery.

  In any of the above cases, examples of the solvent used in the electrolytic solution include carbonates such as propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate; lactones such as γ-butyrolactone; trimethoxy Silane, 1,2-dimethoxyethane, diethyl ether, 2-ethoxyethane, tetrahydrofuran, ether such as 2-methyltetrahydrofuran; Sulfoxide such as dimethyl sulfoxide; 1,3-dioxolane, 4-methyl-1,3-dioxolane, etc. Oxolane derivatives; nitrogen-containing compounds such as acetonitrile and nitromethane; esters such as methyl formate, methyl acetate, butyl acetate, methyl propionate, ethyl propionate, and phosphate triester Glyme compounds such as diglyme, triglyme and tetraglyme; ketones such as acetone, diethyl ketone, methyl ethyl ketone and methyl isobutyl ketone; sulfone compounds such as sulfolane; oxazolidinone derivatives such as 2-methyl-2-oxazolidinone; 1,3-propane sultone; Examples include sultone compounds such as 1,4-butane sultone, 2,4-butane sultone, and 1,8-naphtha sultone.

4.2. Second Embodiment FIG. 2 is a schematic view showing a cross section of an electricity storage device according to a second embodiment. As shown in FIG. 2, the electricity storage device 2 includes a positive electrode 110 in which a positive electrode active material layer 114 is formed on the surface of a positive electrode current collector 112 and a negative electrode 120 in which a negative electrode active material layer 124 is formed on the surface of a negative electrode current collector 122. A protective film 130 provided between the positive electrode 110 and the negative electrode 120, an electrolyte solution 140 that fills between the positive electrode 110 and the negative electrode 120, and a separator 150 provided between the positive electrode 110 and the negative electrode 120. It is provided.

  The electricity storage device 2 is different from the electricity storage device 1 described above in that the protective film 130 is disposed so as to be sandwiched between the positive electrode 110 and the separator 150. In the power storage device 2 illustrated in FIG. 2, the protective film 130 is disposed so as to be sandwiched between the positive electrode 110 and the separator 150, but the protective film 130 is sandwiched between the negative electrode 120 and the separator 150. It may be arranged so that. By adopting such a configuration, even when dendrite is deposited by repeated charge and discharge, the protective film 130 guards and no short circuit occurs. Therefore, the function as an electricity storage device can be maintained.

  The protective film 130 can be formed by, for example, applying a slurry for forming a protective film on the surface of the separator 150, bonding the positive electrode 110 (or the negative electrode 120), and then drying. As a method of applying the protective film-forming slurry to the surface of the separator 150, for example, a doctor blade method, a reverse roll method, a comma bar method, a gravure method, an air knife method, a die coating method, or the like can be applied. The drying treatment of the coating film is preferably performed in a temperature range of 20 to 250 ° C., more preferably 50 to 150 ° C., preferably for a processing time of 1 to 120 minutes, more preferably 5 to 60 minutes.

  Any separator 150 may be used as long as it is electrically stable, chemically stable with respect to the positive electrode active material, the negative electrode active material, or the solvent, and has no electrical conductivity. . For example, a polymer nonwoven fabric, a porous film, glass or ceramic fibers in a paper shape can be used, and a plurality of these may be laminated. In particular, a porous polyolefin film is preferably used, and a composite of this with a heat-resistant material made of polyimide, glass, ceramic fibers or the like may be used.

  The other configuration of the power storage device 2 according to the second embodiment is the same as that of the power storage device 1 according to the first embodiment described with reference to FIG.

4.3. Third Embodiment FIG. 3 is a schematic view showing a cross section of an electricity storage device according to a third embodiment. As shown in FIG. 3, the electricity storage device 3 includes a positive electrode 210 in which a positive electrode active material layer 214 is formed on the surface of a positive electrode current collector 212, and a negative electrode 220 in which a negative electrode active material layer 224 is formed on the surface of a negative electrode current collector 222. An electrolyte 240 filling between the positive electrode 210 and the negative electrode 220, a separator 250 provided between the positive electrode 210 and the negative electrode 220, and a protective film 230 formed so as to cover the surface of the separator 250. It is provided.

  The electricity storage device 3 is different from the electricity storage device 1 and the electricity storage device 2 described above in that the protective film 230 is formed so as to cover the surface of the separator 250. By adopting such a configuration, even when dendrites are deposited by repeated charge and discharge, the protective film 230 guards the short circuit. Therefore, the function as an electricity storage device can be maintained.

  The protective film 230 can be formed, for example, by applying a slurry for forming a protective film on the surface of the separator 250 and drying it. As a method for applying the protective film-forming slurry to the surface of the separator 250, for example, a doctor blade method, a reverse roll method, a comma bar method, a gravure method, an air knife method, a die coating method, or the like can be applied. The drying treatment of the coating film is preferably performed in a temperature range of 20 to 250 ° C., more preferably 50 to 150 ° C., preferably for a processing time of 1 to 120 minutes, more preferably 5 to 60 minutes.

  Regarding other configurations of the power storage device 3 according to the third embodiment, the power storage device 1 according to the first embodiment described with reference to FIG. 1 and the power storage according to the second embodiment described with reference to FIG. Since it is the same as the device 2, the description thereof is omitted.

4.4. As a method of manufacturing an electricity storage device as described above, for example, two electrodes (two of a positive electrode and a negative electrode, or two of electrodes for a capacitor) are stacked with a separator as necessary, Examples include a method in which this is wound or folded in accordance with the shape of the battery and placed in a battery container, and an electrolytic solution is injected into the battery container and sealed. The shape of the battery can be an appropriate shape such as a coin shape, a button shape, a sheet shape, a cylindrical shape, a square shape, or a flat shape.

4.5. Applications The power storage device as described above is suitable as a secondary battery or a capacitor mounted on an automobile such as an electric vehicle, a hybrid car, and a truck, as well as a secondary battery used for AV equipment, OA equipment, communication equipment, It is also suitable as a capacitor.

5. EXAMPLES Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. “Part” and “%” in Examples and Comparative Examples are based on mass unless otherwise specified.

5.1. Synthesis of polymer particles (A1) 5.1.1. Synthesis example 1
<Synthesis of Polymer X>
The inside of an autoclave having an internal volume of 6 L equipped with an electromagnetic stirrer was sufficiently purged with nitrogen, then 2.5 L of deoxygenated pure water and 25 g of ammonium perfluorodecanoate as an emulsifier were charged, and the mixture was stirred at 350 rpm up to 60 ° C. The temperature rose. Next, a mixed gas composed of 70% of vinylidene fluoride (VDF) as a monomer and 30% of propylene hexafluoride (HFP) was charged until the internal pressure reached 20 kg / cm ² . 25 g of Freon 113 solution containing 20% of diisopropyl peroxydicarbonate as a polymerization initiator was injected using nitrogen gas to initiate polymerization. During the polymerization, a mixed gas composed of 60.2% VDF and 39.8% HFP was sequentially injected so that the internal pressure was maintained at 20 kg / cm ² to maintain the pressure at 20 kg / cm ² . Further, since the polymerization rate decreased as the polymerization progressed, the same amount of the same polymerization initiator solution as that described above was injected using nitrogen gas after 3 hours, and the reaction was continued for 3 hours. Then, simultaneously with cooling the reaction liquid, the stirring was stopped and the reaction was stopped after releasing the unreacted monomer, whereby an aqueous dispersion containing 40% of the particles of the polymer X was obtained. As a result of analyzing the obtained polymer X by ¹⁹ F-NMR, the mass composition ratio of each monomer was VDF / HFP = 21/4.

<Synthesis of polymer particles (A1)>
After the inside of the 7-L separable flask was sufficiently purged with nitrogen, 25 parts by mass of an aqueous dispersion containing the particles of the polymer X obtained in the above step in terms of the polymer X was added to the emulsifier “ADEKA rear soap SR1025”. (Trade name, manufactured by ADEKA Corporation) 0.5 parts by mass, methyl methacrylate (MMA) 30 parts by mass, 2-ethylhexyl acrylate (EHA) 40 parts by mass, methacrylic acid (MAA) 5 parts by mass and water 130 parts by mass The portions were sequentially charged and stirred at 70 ° C. for 3 hours to allow the polymer X to absorb the monomer. Next, 20 mL of a tetrahydrofuran solution containing 0.5 part by mass of azobisisobutyronitrile, which is an oil-soluble polymerization initiator, is added, heated to 75 ° C., reacted for 3 hours, and further reacted at 85 ° C. for 2 hours. went. Thereafter, the reaction is stopped after cooling, and the aqueous dispersion S1 containing 40% of the polymer particles (A1) containing the polymer X and the polymer Y is adjusted to pH 7 with a 2.5N aqueous sodium hydroxide solution. Got.

  About the obtained water dispersion S1, a particle size distribution is measured using the particle size distribution measuring apparatus (The model "FPAR-1000" by Otsuka Electronics Co., Ltd.) which makes a dynamic light scattering method a measurement principle, From the particle size distribution, The number average particle diameter (Da1) was determined to be 330 nm.

10 g of the obtained aqueous dispersion S1 was weighed into a Teflon (registered trademark) petri dish having a diameter of 8 cm and dried at 120 ° C. for 1 hour to form a film. 1 g of the obtained film (polymer) was immersed in 400 mL of toluene and shaken at 50 ° C. for 3 hours. Next, the toluene phase was filtered through a 300-mesh wire mesh to separate insoluble components, and the weight of the residue (Y (g)) obtained by evaporating and removing the dissolved toluene was measured from the following formula ( When the toluene insoluble content was determined by 1), the toluene insoluble content of the polymer particles (A1) was 85%.
Toluene insoluble content (%) = ((1-Y) / 1) × 100 (1)

  Further, when the obtained film (film composed of polymer particles (A1)) was measured by a differential scanning calorimeter (manufactured by NETZSCH, DSC204F1 Phoenix), the melting temperature Tm was not observed, and the single glass transition Since the temperature Tg was observed at −5 ° C., the obtained polymer particles (A1) are presumed to be polymer alloy particles.

Further, the obtained film (polymer) was subjected to thermogravimetric analysis with a thermal analyzer (manufactured by Shimadzu Corporation, model “DTG-60A”). The temperature at which the polymer particles A1 are reduced by 10% by weight when heated at a rate of temperature increase of 20 ° C./min in an air atmosphere (hereinafter, this reduction start temperature is expressed as “T ₁₀ ”) was 338 ° C. .

5.1.2. Synthesis example 2
In Synthesis Example 1, an aqueous dispersion containing polymer particles (A1) having the composition shown in Table 1 is prepared without using the polymer X, and water is reduced in pressure according to the solid content concentration of the aqueous dispersion. By removing or adding, an aqueous dispersion S2 having a solid concentration of 40% was produced. As a result of measurement of insoluble toluene in the same manner as in Synthesis Example 1, the obtained polymer particles (A1), DSC measurement results (glass transition temperature Tg, melting temperature Tm), and TG measurement results (reduction start temperature T ₁₀₎ ) Is also shown in Table 1.

5.1.3. Synthesis example 3
In a temperature-controllable autoclave equipped with a stirrer, water 200 parts by mass, sodium dodecylbenzenesulfonate 0.6 parts by mass, potassium persulfate 1.0 part by mass, sodium bisulfite 0.5 part by mass, α-methylstyrene The monomer shown in the column of 0.5 part by weight of dimer, 0.3 part by weight of dodecyl mercaptan and the polymer (A1) in Table 1 was charged all at once, and the temperature was raised to 70 ° C. to conduct a polymerization reaction for 8 hours. . Thereafter, the temperature was raised to 80 ° C., and the reaction was further performed for 3 hours to obtain a latex. The pH of this latex was adjusted to 7.5, and 5 parts by mass of sodium tripolyphosphate (added as an aqueous solution having a solid content conversion value and a concentration of 10% by mass) was added. Thereafter, the residual monomer was removed by steam distillation, and concentrated under reduced pressure to obtain an aqueous dispersion S3 containing 50% by mass of polymer particles (A1). As a result of measurement of insoluble toluene in the same manner as in Synthesis Example 1, the obtained polymer particles (A1), DSC measurement results (glass transition temperature Tg, melting temperature Tm), and TG measurement results (reduction start temperature T ₁₀₎ ) Is also shown in Table 1.

5.1.4. Synthesis example 4
A separable flask having a volume of 7 liters was charged with 150 parts by mass of water and 0.3 parts by mass of sodium dodecylbenzenesulfonate, and the inside of the separable flask was sufficiently purged with nitrogen. On the other hand, in another container, 60 parts by mass of water, ether sulfate type emulsifier (trade name “ADEKA rear soap SR1025”, manufactured by ADEKA Corporation) as an emulsifier, 0.8 parts by mass in terms of solid content, and acrylic acid as a monomer 83 parts by mass of n-butyl (BA), 5 parts by mass of acrylonitrile (AN), 5 parts by mass of cyclohexyl acrylate (CHMA), 1 part by mass of 2-hydroxyethyl methacrylate (HEMA), 2 parts by mass of methacrylic acid (MAA), Simply add 1 part by weight of acrylic acid (AA), 0.5 part by weight of allyl methacrylate (AMA), 2.5 parts by weight of glycidyl methacrylate (GMA) and stir well to contain a mixture of the above monomers. A mass emulsion was prepared. Then, the temperature inside the separable flask was started, and when the temperature inside the separable flask reached 60 ° C., 0.5 parts by mass of ammonium persulfate was added as a polymerization initiator. Then, when the temperature inside the separable flask reaches 70 ° C., the addition of the monomer emulsion prepared above is started, and the temperature inside the separable flask is maintained at 70 ° C. The emulsion was added slowly over 3 hours. Thereafter, the temperature inside the separable flask was raised to 85 ° C., and this temperature was maintained for 3 hours to carry out the polymerization reaction. After 3 hours, the separable flask was cooled to stop the reaction, and ammonium water was added to adjust the pH to 7.6, thereby obtaining an aqueous dispersion S4 containing 30% of polymer particles (A1). It was. As a result of measurement of insoluble toluene in the same manner as in Synthesis Example 1, the obtained polymer particles (A1), DSC measurement results (glass transition temperature Tg, melting temperature Tm), and TG measurement results (reduction start temperature T ₁₀₎ ) Is also shown in Table 1.

5.1.5. Synthesis Examples 5-7
An aqueous dispersion containing the polymer (A) having the composition shown in Table 1 was prepared in the same manner as in Synthesis Example 4 except that the monomer composition and the amount of the emulsifier were appropriately changed, and the solid of the aqueous dispersion was prepared. By removing or adding water under reduced pressure according to the partial concentration, an aqueous dispersion having a solid concentration of 30% was obtained. As a result of measurement of insoluble toluene in the same manner as in Synthesis Example 1, the obtained polymer particles (A1), DSC measurement results (glass transition temperature Tg, melting temperature Tm), and TG measurement results (reduction start temperature T ₁₀₎ ) Is also shown in Table 1.

5.1.6. Synthesis Example 8
In a temperature-controllable autoclave equipped with a stirrer, 300 parts by weight of water, 0.9 part by weight of sodium dodecylbenzenesulfonate, 1.0 part by weight of potassium persulfate, 0.5 part by weight of sodium bisulfite, α-methylstyrene 0.2 parts by mass of dimer, 0.2 parts by mass of dodecyl mercaptan, and the polymerization components shown in Table 1 were charged all at once, and the temperature was raised to 50 ° C. to carry out the polymerization reaction for 16 hours. After confirming that the polymerization addition rate was 90% or more, the reaction temperature was set to 70 ° C., and 1.0 part by mass of α-methylstyrene dimer and 0.3 part by mass of dodecyl mercaptan were added, followed by further reaction for 3 hours. . After completion of the polymerization reaction, the latex pH was adjusted to 7.5, and 5 parts by mass of sodium tripolyphosphate (in terms of solid content) was added. Thereafter, the residual monomer was treated with steam distillation and concentrated under reduced pressure to a solid content of 50% to obtain an aqueous dispersion containing 50% of polymer particles (A1). As a result of measurement of insoluble toluene in the same manner as in Synthesis Example 1, the obtained polymer particles (A1), DSC measurement results (glass transition temperature Tg, melting temperature Tm), and TG measurement results (reduction start temperature T ₁₀₎ ) Is also shown in Table 1.

5.1.7. Synthesis Examples 9 to 11
An aqueous dispersion containing the polymer particles (A1) shown in Table 1 was prepared in the same manner as in Synthesis Example 8 except that the type and amount (parts) of each monomer were as shown in Table 1. I got each. As a result of measurement of insoluble toluene in the same manner as in Synthesis Example 1, the obtained polymer particles (A1), DSC measurement results (glass transition temperature Tg, melting temperature Tm), and TG measurement results (reduction start temperature T ₁₀₎ ) Is also shown in Table 1.

5.2. Synthesis of polymer particles (A2) 5.2.1. Synthesis Example 12
100 parts by mass of styrene, 10 parts by mass of t-dodecyl mercaptan, 0.8 parts by mass of sodium dodecylbenzenesulfonate, 0.4 parts by mass of potassium persulfate, and 200 parts by mass of water were placed in a 2 L flask and stirred. Then, the temperature was raised to 80 ° C. in a nitrogen gas atmosphere, and polymerization was performed for 6 hours. As a result, an aqueous dispersion containing polymer particles having a polymerization yield of 98% and a number average particle diameter of 170 nm and a standard deviation of the particle diameter of 0.02 μm was obtained. The polymer particles had a toluene dissolved content of 98%, and the molecular weight measured by gel permeation chromatography was weight average molecular weight (Mw) = 5,000 and number average molecular weight (Mn) = 3,100.

  After sufficiently substituting the inside of the reaction vessel with nitrogen, 5 parts by mass of polymer particles (in terms of solid content) and 1.0 part by mass of sodium lauryl sulfate were obtained. Then, 0.5 parts by mass of potassium persulfate, 400 parts by mass of water, 45 parts by mass of styrene, and 50 parts by mass of divinylbenzene were mixed and stirred at 30 ° C. for 10 minutes to allow the polymer particles to absorb the monomer. Then, it heated up at 70 degreeC and reacted for 3 hours. Then, after cooling, the reaction was stopped, the pH was adjusted to 7 with a 2.5N aqueous sodium hydroxide solution, and an aqueous dispersion L1 containing 20% of polymer particles (A2) was obtained.

  The particle size distribution is measured using a particle size distribution measuring apparatus (model “FPAR-1000” manufactured by Otsuka Electronics Co., Ltd.) having a dynamic light scattering method as a measurement principle, and the number average of the polymer particles (A2) is determined from the particle size distribution. The particle diameter (Da2) was determined to be 380 nm.

  100 g of the aqueous dispersion of the polymer particles (A2) was weighed and dried at 120 ° C. for 1 hour. The obtained solid was pulverized in an agate mortar to obtain a powder (polymer particles (A2)).

As a result of performing toluene insoluble content measurement, DSC measurement and TG measurement of the obtained powder (powder composed of polymer particles (A2)) in the same manner as in Synthesis Example 1, the toluene insoluble content was 99%. the glass transition temperature Tg and the melting temperature Tm can not be observed, weight loss initiation temperature _{T 10} was 379 ° C.. FIG. 4 is a TGA chart of the polymer particles (A2) obtained in Synthesis Example 12. According to FIG. 4, it can be read that the temperature (T ₁₀ ) at which the weight of the polymer particles (A2) obtained in Synthesis Example 12 is reduced by 10% by weight in an air atmosphere is 379 ° C.

  In order to analyze the structure of the particles in more detail, the aqueous dispersion of polymer particles containing 20% of the obtained polymer particles (A2) was dried and solidified, and adjusted to pH 10 that was 20 times the solid content. The resultant was washed three times with the aqueous ammonia and further four times with ion-exchanged water to completely remove the water-soluble component, and then dried and solidified again to obtain a powder of polymer particles (A2). When this powder was observed using a Hitachi transmission electron microscope H-7650 (manufactured by Hitachi High-Technologies Corporation), it was a solid polymer particle having an average particle diameter of 100 particles observed of 380 nm.

5.2.2. Synthesis Example 13
In the synthesis example 12, except that the composition and the amount of the emulsifier were appropriately changed, an aqueous dispersion containing the polymer particles (A2) having the composition shown in Table 2 was prepared, and according to the solid content concentration of the aqueous dispersion. By removing or adding water under reduced pressure, an aqueous dispersion L2 having a solid concentration of 20% was obtained. The resulting polymer particles (A2) were measured for toluene insolubles in the same manner as in Synthesis Example 1, the results of DSC measurement (glass transition temperature Tg, melting temperature Tm), and the results of TG measurement (reduction start temperature T _10). ) Is also shown in Table 2.

  In order to analyze the structure of the particles in more detail, the aqueous dispersion of polymer particles containing 20% of the obtained polymer particles (A2) was dried and solidified, and adjusted to pH 10 that was 20 times the solid content. The resultant was washed three times with the aqueous ammonia and further four times with ion-exchanged water to completely remove the water-soluble component, and then dried and solidified again to obtain a powder of polymer particles (A2). When this powder was observed using a Hitachi transmission electron microscope H-7650 (manufactured by Hitachi High-Technologies Corporation), the observed 100 particles were hollow polymer particles having an average particle diameter of 420 nm and a particle inner diameter of 220 nm. Yes, the volume porosity was 14%.

5.2.3. Synthesis Example 14
In a pressure-resistant reaction vessel with a capacity of 2 liters equipped with a stirrer and a temperature controller, 109.5 parts by mass of water, 0.02 parts by mass of sodium dodecylbenzenesulfonate as an emulsifier, 0.5 parts by mass of octyl glycol as a molecular weight regulator and polymerization As an initiator, 0.5 part by mass of sodium persulfate was added. Next, 20% of a monomer mixture obtained by mixing 20 parts by mass of acrylic acid and 80 parts by mass of methyl methacrylate was charged into a pressure resistant reactor. Thereafter, the temperature is raised to 75 ° C. while stirring, and a polymerization reaction is carried out for 1 hour after reaching 75 ° C., and then the remaining monomer mixture is continuously put into a pressure-resistant reaction vessel over 2 hours while maintaining the temperature at 75 ° C. Added. Thereafter, aging was further performed for 2 hours to obtain an aqueous dispersion of polymer particles (A2a) having a solid content of 40% and a number average particle diameter of 400 nm.

  350 parts by mass of water was put into a pressure-resistant reaction vessel having a capacity of 2 liters equipped with a stirrer and a temperature controller, and 10 parts by mass of the above polymer particles (A2a) having a number average particle diameter of 400 nm were added thereto. did. Next, a monomer mixture obtained by mixing 50 parts by mass of ethylene glycol dimethacrylate, 37 parts by mass of methyl methacrylate and 3 parts by mass of acrylic acid was charged into the reaction vessel while stirring. Thereafter, the temperature of the solution was increased to 80 ° C. while stirring, 0.4 part by mass of sodium persulfate was added as a polymerization initiator, and the mixture was aged for 4 hours while maintaining the temperature of 80 ° C. After cooling to room temperature, 5 parts by mass of 25% ammonium water was added and aged for 3 hours to obtain an aqueous dispersion L3 containing 20% of polymer particles (A2).

The resulting polymer particles (A2) were measured for toluene insolubles in the same manner as in Synthesis Example 1, the results of DSC measurement (glass transition temperature Tg, melting temperature Tm), and the results of TG measurement (reduction start temperature T _10). ) Is also shown in Table 2.

  The particle size distribution is measured using a particle size distribution measuring apparatus (model “FPAR-1000” manufactured by Otsuka Electronics Co., Ltd.) having a dynamic light scattering method as a measurement principle, and the number average of the polymer particles (A2) is determined from the particle size distribution. The particle diameter (Da2) was determined to be 1000 nm.

  In order to analyze the structure of the particles in more detail, the aqueous dispersion of polymer particles containing 20% of the obtained polymer particles (A2) was dried and solidified, and adjusted to pH 10 that was 20 times the solid content. The resultant was washed three times with the aqueous ammonia and further four times with ion-exchanged water to completely remove the water-soluble component, and then dried and solidified again to obtain a powder of polymer particles (A2). This powder was observed using a Hitachi transmission electron microscope H-7650 (manufactured by Hitachi High-Technologies Corporation). The volume porosity was 51%.

The abbreviations or names of the components in Table 1 and Table 2 represent the following compounds, respectively.
<Compound having two or more polymerizable unsaturated groups>
EDMA: ethylene glycol dimethacrylate DVB: divinylbenzene <monomer having a fluorine atom>
・ VDF: Vinylidene fluoride ・ HFP: Propylene hexafluoride <Unsaturated carboxylic acid>
MAA: methacrylic acid TA: itaconic acid AA: acrylic acid <unsaturated carboxylic acid ester>
MMA: methyl methacrylate, EHA: 2-ethylhexyl acrylate, HEMA: 2-ethylhexyl methacrylate, BA: n-butyl acrylate, BMA: n-butyl methacrylate, AMA: allyl methacrylate, GMA: glycidyl methacrylate・ AN: Acrylonitrile ・ CHMA: Cyclohexyl methacrylate <Aromatic vinyl compound>
ST: Styrene <conjugated diene compound>
-BD: 1,3-butadiene In addition, the description of "-" in Table 1 and Table 2 shows that the applicable component was not used.

5.3. Example 1
5.3.1. Preparation of composition for electricity storage device The aqueous dispersion S1 and the aqueous dispersion L1 are mixed with respect to 94.8 parts by mass of the polymer particles (A2) so that the polymer particles (A1) are 5 parts by mass, Furthermore, 10 parts by mass of Zn (NH ₃ ) ₄ (CH ₃ COO) ₂ as a metal complex (B), 0.2 part by mass of a water-soluble polymer (trade name “CMC1120” manufactured by Daicel Corporation), and 275 parts by mass of water are T . K. Mixing and dispersing treatment was performed using a film mix (R) 56-50 type (manufactured by PRIMIX Co., Ltd.) to prepare a composition for an electricity storage device.

  As a result of measuring the toluene insoluble content of the composition for an electricity storage device thus obtained by the same method as in “5.1.1. Synthesis Example 1”, the toluene insoluble content was 99%.

Further, the ionic functional group amount Ma (mmol) of the polymer particles (A1) and the polymer particles (A2) was determined by the following calculation formula, and is shown in Table 3 together.
-Amount of ionic functional group in 1 g of each polymer particle (mol / 1 g) = (mass part of structural unit having ionic functional group (g) ÷ ion when the total of the structural units of each polymer particle is 100 g) Molecular weight of structural unit having a functional group (g / mol)) ÷ 100
Ma (mmol) = (Amount of ionic functional group in 1 g of each polymer particle (mol / 1 g) × mass part of each polymer particle (g)) × 1000

5.3.2. Production of positive electrode <Preparation of positive electrode active material>
Commercially available lithium iron phosphate (LiFePO ₄ ) was pulverized in an agate mortar and classified using a sieve to prepare active material particles having a particle diameter (D50 value) of 0.5 μm.

<Preparation of slurry for positive electrode>
A biaxial planetary mixer (product name “TK Hibismix 2P-03” manufactured by PRIMIX Co., Ltd.), 4 parts by mass of polyvinylidene fluoride (in terms of solid content), 100 parts by mass of the active material particles, 5 parts by mass of acetylene black, and 68 parts by mass of N-methylpyrrolidone was added and stirred at 60 rpm for 1 hour. Further, 32 parts by mass of N-methylpyrrolidone was added and stirred for 1 hour to obtain a paste. The obtained paste was stirred at 200 rpm for 2 minutes, 1800 rpm for 5 minutes, and further under vacuum (5.0 × 10 ³ ) using a stirring defoaming machine (trade name “Awatori Netaro”, manufactured by Shinky Corporation). The slurry for positive electrode was prepared by stirring and mixing at 1800 rpm for 1.5 minutes at Pa).

<Preparation of electrode for positive electrode>
The positive electrode slurry was uniformly applied to the surface of a current collector made of aluminum foil by a doctor blade method so that the film thickness after drying was 100 μm, and dried at 120 ° C. for 20 minutes. Then, the positive electrode with the positive electrode active material layer formed on the surface of the current collector was obtained by pressing with a roll press so that the density of the film (active material layer) was 2.0 g / cm ³ .

5.3.3. Production of protective film (production of separator with protective film)
The composition for an electricity storage device obtained in the above “5.3.1. Preparation of composition for electricity storage device” on both sides of a separator (trade name “Celguard # 2400” manufactured by Celgard Co., Ltd.) made of a polypropylene porous membrane. Was applied using a dip coating method, followed by drying at 80 ° C. for 10 minutes to form protective films on both sides of the separator. The thickness of the protective film obtained was 2 μm on one side (total of 4 μm on both the front and back sides).

5.3.4. Production of negative electrode <Preparation of slurry for negative electrode>
A biaxial planetary mixer (product name “TK Hibismix 2P-03” manufactured by PRIMIX Co., Ltd.) and a thickener (product name “CMC2200” manufactured by Daicel Corporation) 1 part by mass (solid content conversion), negative electrode active As materials, 100 parts by mass of graphite (in terms of solid content) and 68 parts by mass of water were added and stirred at 60 rpm for 1 hour. Thereafter, 2 parts by mass (in terms of solid content) of the polymer particle (A1) aqueous dispersion S4 prepared in Synthesis Example 4 was added, and the mixture was further stirred for 1 hour to obtain a paste. Water was added to the obtained paste to adjust the solid content to 50%, and then the mixture was stirred at 200 rpm for 2 minutes at 1800 rpm at 200 rpm using a stirring defoamer (trade name “Netaro Awatori” manufactured by Shinky Co., Ltd.). The slurry for negative electrode was prepared by stirring and mixing for 5 minutes at 1800 rpm for 1 minute at 1800 rpm.

<Preparation of electrode for negative electrode>
The negative electrode slurry was uniformly applied to the surface of a current collector made of a copper foil having a thickness of 20 μm by a doctor blade method so that the film thickness after drying was 80 μm, followed by drying at 120 ° C. for 20 minutes. Then, the negative electrode by which the negative electrode active material layer was formed in the surface of the electrical power collector was obtained by pressing with a roll press so that the density of an electrode layer might be 1.5 g / cm < ³ >.

5.3.5. Assembly of Lithium Ion Battery Cell A bipolar coin cell (Hosen Co., Ltd.) obtained by punching and molding the negative electrode produced above to a diameter of 15.95 mm in an Ar-substituted glove box with a dew point of −80 ° C. or lower. And product name “HS flat cell”). Next, the separator with the protective film obtained in “5.3.3 Production of protective film” punched out to a diameter of 24 mm was placed, and after injecting 500 μL of the electrolyte solution so that air did not enter, The positive electrode with a protective film manufactured in the above is punched into a shape of 16.16 mm and placed so that the separator and the protective film formed on the positive electrode face each other, and the outer body of the bipolar coin cell is closed with a screw. The lithium ion battery cell (electric storage device) was assembled by sealing. The electrolytic solution used here is a solution obtained by dissolving LiPF ₆ at a concentration of 1 mol / L in a solvent of ethylene carbonate / ethyl methyl carbonate = 1/1 (mass ratio).

5.3.6. Measurement of remaining capacity rate and resistance increase rate The battery cell produced above was placed in a thermostatic bath at 25 ° C., charging was started at a constant current (0.2 C), and when the voltage reached 4.1 V, it was continuously determined. Charging was continued at a voltage (4.1 V), and charging was completed (cut off) when the current value reached 0.01C. Next, discharging was started at a constant current (0.2 C), and the time when the voltage reached 2.5 V was regarded as discharging completion (cut-off) (aging charge / discharge).

  The cell after the aging charge / discharge is put in a thermostat at 25 ° C., and charging is started at a constant current (0.2 C). When the voltage reaches 4.1 V, the cell is continuously maintained at a constant voltage (4.1 V). Charging was continued, and charging was completed (cut off) when the current value reached 0.01C. Next, discharge was started at a constant current (0.2 C), and when the voltage reached 2.5 V, the discharge was completed (cut off), and C1 which was the value of the discharge capacity (initial) at 0.2 C was measured. did.

The cell after the discharge capacity (initial) measurement was placed in a constant temperature bath at 25 ° C., charging was started at a constant current (0.2 C), and when the voltage reached 4.1 V, the constant voltage (4.1 V) was continued. The charging was continued at), and the time when the current value reached 0.01 C was defined as the completion of charging (cut-off).

  An EIS measurement ("Electrochemical Impedance Spectroscopy", "electrochemical impedance measurement") was performed on the charged cell, and an initial resistance value EISA was measured.

  Next, the cell in which the initial resistance value EISa was measured was placed in a constant temperature bath at 60 ° C., and charging was started at a constant current (0.2 C). When the voltage reached 4.4 V, the constant voltage (4 4V), charging was continued for 168 hours (overcharge acceleration test).

  After that, the charged cell was placed in a constant temperature bath at 25 ° C., the cell temperature was lowered to 25 ° C., and then discharging was started at a constant current (0.2 C), and the voltage became 2.5V. Was completed (cutoff), and C2 as a value of the discharge capacity at 0.2 C (after the test) was measured.

  The cell having the above discharge capacity (after the test) is placed in a constant temperature bath at 25 ° C., and charging is started at a constant current (0.2 C). When the voltage reaches 4.1 V, the constant voltage (4.1 V) continues. The charging was continued at, and the time when the current value reached 0.01 C was regarded as charging completion (cut-off). Next, discharging was started at a constant current (0.2 C), and the time when the voltage reached 2.5 V was regarded as completion of discharging (cut-off). EIS measurement of this cell was performed, and EISb which is a resistance value after application of thermal stress and overcharge stress was measured.

The remaining capacity rate obtained by substituting the above measured values into the following formula (7) is 90%, and the resistance increase rate obtained by substituting the above measured values into the following formula (8) is 180%. there were.
Remaining capacity ratio (%) = (C2 / C1) × 100 (7)
Resistance increase rate (%) = (EISb / EISa) × 100 (8)
When this remaining capacity ratio is 75% or more and the resistance increase rate is 300% or less, it can be evaluated that the durability is good.

  In the above measurement conditions, “1C” indicates a current value at which discharge is completed in one hour after constant current discharge of a cell having a certain electric capacity. For example, “0.1 C” is a current value at which discharge is completed over 10 hours, and “10 C” is a current value at which discharge is completed over 0.1 hours.

<Evaluation of shutdown characteristics and 200 ° C resistance maintenance ratio>
1M LiPF ₆ ethylene carbonate / diethyl carbonate (3/7 weight ratio) (manufactured by Kishida Chemical Co., Ltd.) and the separator with protective film obtained in the above “5.3.3 Production of protective film” A unit in contact with and interposed between current collectors was prepared and loaded into a flat cell (Takumi Giken, flat cell) to produce an evaluation cell.

  The evaluation cell was allowed to stand in a hot stove, the temperature was raised from 30 ° C. to 200 ° C. at a rate of 5 ° C./min, and held at 200 ° C. for 20 minutes. During this process, the resistance at 1 Hz measured with an LCR meter (manufactured by Hioki Electric Co., Ltd., device name “LCR HiTESTER”) when reaching 160 ° C., 200 ° C. and holding at 200 ° C. for 20 minutes is 130Ω, and held at 200 ° C. for 20 minutes. The internal resistance was divided by the internal resistance when reaching 200 ° C., and the resistance maintenance ratio (unit:%) multiplied by 100 was 80%. If the 160 ° C. internal resistance is 100Ω or more, it is judged that the shutdown characteristic is good and is described as “◯” in Table 3, and if the 200 ° C. resistance maintenance rate is less than 40%, it is judged as “poor”. Table 3 shows “good” when it is 40% or more and less than 70%, and “good” when it is 70% or more.

5.4. Examples 2-9, Comparative Example 1
An electricity storage device was produced and evaluated in the same manner as in Example 1 except that each component shown in Table 3 was blended in the usage ratio shown in Table 3. The evaluation results are also shown in Table 3.

The abbreviations or names of the components in Table 3 and Table 4 represent the following compounds, respectively.
<Water-soluble polymer (D)>
CMC: manufactured by Daicel Corporation, trade name “CMC1120”, sodium carboxymethyl cellulose. PAA: manufactured by Wako Pure Chemical Industries, Ltd., research reagent, sodium polyacrylate (MW: 350,000)
Isoban # 10: manufactured by Kuraray Co., Ltd., trade name “Isoban # 10”, neutralized NaOH of an alternating copolymer of maleic anhydride and isobutylene, neutralization degree 0.8
<Inorganic filler (E)>
Alumina: manufactured by Sumitomo Chemical Co., Ltd., trade name “AKP-3000”, average particle size 0.74 μm
・ Magnesia: manufactured by Tateho Chemical Industry Co., Ltd., trade name “PUREMAG® FNM-G”, average particle size 0.50 μm
-Titania: manufactured by Titanium Industry Co., Ltd., trade name “KR380”, rutile type, average particle size 0.38 μm
In addition, the notation of “-” in Table 3 and Table 4 indicates that the corresponding component was not used.

5.5. Example 10
5.5.1. Preparation and evaluation of the composition for electrical storage devices The composition for electrical storage devices shown in Table 3 was prepared like Example 1 except having mix | blended each component shown in Table 4 with the use ratio shown in Table 4.

About the composition for electrical storage devices obtained in this way, toluene insoluble content measurement, DSC measurement (glass transition temperature Tg, melting temperature Tm) and TG measurement (start of weight loss) by the same method as “5.1.1. Synthesis Example 1” As a result of the temperature T ₁₀ ), the toluene insoluble content was 99%.

5.5.2. Preparation and evaluation of slurry for electricity storage device electrode <Synthesis of silicon material (active material)>
A mixture of pulverized silicon dioxide powder (average particle size 10 μm) and carbon powder (average particle size 35 μm) was heated in a nitrogen stream (0.5 NL / min) in an electric furnace adjusted to a temperature of 1100 to 1600 ° C. ) A heat treatment for 10 hours was performed to obtain a silicon oxide powder (average particle diameter of 8 μm) represented by the composition formula SiO _x (x = 0.5 to 1.1). 300 g of this silicon oxide powder was charged into a batch-type heating furnace, and the temperature was raised from room temperature (25 ° C.) to 1100 ° C. at a temperature raising rate of 300 ° C./h while maintaining a reduced pressure of 100 Pa absolute pressure with a vacuum pump. . Next, heat treatment (graphite coating treatment) was performed at 1100 ° C. for 5 hours while introducing methane gas at a flow rate of 0.5 NL / min while maintaining the pressure in the heating furnace at 2000 Pa. After the completion of the graphite coating treatment, the powder was cooled to room temperature at a temperature decrease rate of 50 ° C./h to obtain about 330 g of graphite-coated silicon oxide powder. This graphite-coated silicon oxide is a conductive powder (active material) in which the surface of silicon oxide is coated with graphite, and its average particle diameter is 10.5 μm. The ratio of the graphite film in the case of mass% was 2 mass%.

<Preparation of slurry for electricity storage device electrode>
Artificial graphite (manufactured by Hitachi Chemical Co., Ltd., trade name “MAG”) having high crystallinity as a negative electrode active material in a biaxial planetary mixer (trade name “TK Hibismix 2P-03” manufactured by PRIMIX Corporation) ”) 80 parts by mass (converted to solid content), 20 parts by mass of the graphite-coated silicon oxide powder obtained above (converted to solids), and 68 parts by mass of water were added and stirred at 60 rpm for 1 hour. Went. Thereafter, water and the power storage device composition obtained above were added to the obtained paste in an amount corresponding to 2.1 parts by mass of the polymer particles (A) contained therein, and the solid content concentration was 50 masses. %, And then using a stirring defoamer (trade name “Netaro Awatori” manufactured by Shinky Co., Ltd.) for 2 minutes at 200 rpm and 5 minutes at 1800 rpm, and further under reduced pressure (about 2.5 × 10 × 10). ⁴ Pa), a slurry for an electricity storage device electrode was prepared by stirring and mixing at 1800 rpm for 1.5 minutes.

5.5.3. Production and evaluation of electricity storage device electrode <Production of electricity storage device electrode>
The electricity storage device electrode slurry obtained above was uniformly applied to the surface of a current collector made of copper foil having a thickness of 20 μm by a doctor blade method so that the film thickness after drying was 80 μm. It was dried for 10 minutes and then dried at 120 ° C. for 10 minutes. Then, the electrical storage device electrode (negative electrode) was obtained by pressing with a roll-press machine so that the density of an active material layer may be 1.6 g / cm < ³ >.

<Adhesion evaluation>
A test piece having a width of 2 cm and a length of 12 cm was cut out from the electricity storage device electrode (negative electrode) obtained above, and the surface of the test piece on the active material layer side was coated with a double-sided tape having a width of 25 mm (product name “Nichiban Co., Ltd. It was affixed on the aluminum plate using a Nystack (registered trademark) ”. On the other hand, a 18 mm wide tape (manufactured by Nichiban Co., Ltd., trade name “Cello Tape (registered trademark)”, prescribed in JIS Z1522) was attached to the surface of the current collector of the test piece. The force (N / m) when this 18 mm wide tape was peeled 2 cm in the 90 ° direction at a speed of 50 mm / min was measured 6 times, and the average value was calculated as the adhesion strength (peel strength, N / m). It can be evaluated that the larger the peel strength value, the higher the adhesion strength between the current collector and the active material layer, and the more difficult the active material layer peels from the current collector. Quantitatively, when the peel strength value is 8 N / m or more, it can be determined that the adhesion strength is good. The evaluation results at this time were determined as follows, and the evaluation results of the adhesion evaluation are also shown in Table 4.
A: Peel strength value is 8 N / m or more ○: Peel strength value is 5 N / m or more and less than 8 N / m ×: Peel strength value is less than 5 N / m

5.5.4. Manufacturing and evaluation of electricity storage devices <Manufacture of counter electrode (positive electrode)>
Biaxial planetary mixer (product name “TK Hibismix 2P-03” manufactured by PRIMIX Corporation) and electrochemical device electrode binder (product name “KF polymer # 1120” manufactured by Kureha Co., Ltd.) 4.0 mass Parts (solid content conversion value), conductive auxiliary agent (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name “Denka Black 50% press product”) 3.0 parts by mass, LiCoO ₂ having an average particle size of 5 μm as a positive electrode active material 100 parts by mass (in terms of solid content) and 36 parts by mass of N-methylpyrrolidone were added, and the mixture was stirred at 60 rpm for 2 hours. After adding N-methylpyrrolidone to the obtained paste and adjusting the solid content concentration to 65% by mass, using a stirring defoaming machine (trade name “Awatori Netaro”, manufactured by Shinky Co., Ltd.), 200 rpm The slurry for positive electrode was prepared by stirring and mixing at 1,800 rpm for 5 minutes at 1,800 rpm for 5 minutes and further under reduced pressure (about 2.5 × 10 ⁴ Pa) for 1.5 minutes. The positive electrode slurry was uniformly applied to the surface of the current collector made of aluminum foil by a doctor blade method so that the film thickness after solvent removal was 80 μm, and the solvent was removed by heating at 120 ° C. for 20 minutes. . Then, the counter electrode (positive electrode) was obtained by pressing with a roll press so that the density of an active material layer might be 3.0 g / cm < ³ >.

<Assembly of lithium-ion battery cells>
In a glove box substituted with Ar so that the dew point is −80 ° C. or less, the negative electrode produced above was punched and molded to a diameter of 15.95 mm. A bipolar coin cell (trade name “HS Mounted on a flat cell "). Next, a separator made of a polypropylene porous film punched to a diameter of 24 mm (product name “Celguard # 2400” manufactured by Celgard Co., Ltd.) was placed, and after injecting 500 μL of electrolyte so that air did not enter, A lithium ion battery cell (power storage device) was assembled by placing the positive electrode manufactured in the above-described method by punching and molding the positive electrode to a diameter of 16.16 mm, and sealing the outer body of the bipolar coin cell with a screw. The electrolytic solution used here is a solution obtained by dissolving LiPF ₆ at a concentration of 1 mol / L in a solvent of ethylene carbonate / ethyl methyl carbonate = 1/1 (mass ratio).

<Evaluation of 10th cycle retention>
About the electrical storage device manufactured above, charging was started at a constant current (0.5 C) in a thermostatic chamber adjusted to 25 ° C., and when the voltage reached 4.2 V, the constant voltage (4. Charging is continued at 2V), and charging is completed (cut off) when the current value reaches 0.05C. Next, discharging was started at a constant current (0.5 C), and when the voltage reached 3 V, discharging was completed (cut off), and the first discharge capacity at 0.5 C was measured. The charge / discharge was repeated 9 times, and the 10th cycle retention rate (%) was calculated by calculating the ratio (percent%) of the 10th discharge capacity to the first discharge capacity. When the 10th cycle retention rate exceeds 80%, it can be determined that the charge / discharge cycle characteristics are good. The evaluation results at this time were determined as follows, and the evaluation results of the tenth cycle retention were also shown in Table 4.
A: Retention rate at 10th cycle is 80% or more B: Retention rate at 10th cycle is 50% or more and less than 80% X: Retention rate at 10th cycle is less than 50%

<Evaluation of charge / discharge rate characteristics>
About the electrical storage device manufactured above, charging was started at a constant current (0.2 C) in a thermostatic chamber adjusted to 25 ° C., and when the voltage reached 4.2 V, the constant voltage (4. Charging was continued at 2 V), and the charging capacity at 0.2 C was measured with the time when the current value reached 0.01 C as the completion of charging (cut-off). Next, discharge was started at a constant current (0.2 C), and when the voltage reached 2.7 V, the discharge was completed (cut off), and the discharge capacity at 0.2 C was measured.

  Next, charging is started at a constant current (3C) for the same cell, and when the voltage reaches 4.2V, charging is continued at a constant voltage (4.2V). The charging capacity at 3C was measured with the time point of becoming the completion of charging (cut-off). Next, discharge was started at a constant current (3C), and when the voltage reached 2.7 V, the discharge was completed (cut off), and the discharge capacity at 3C was measured.

Using the measured values above, calculate the charge rate (%) by calculating the ratio (percent%) of the charge capacity at 3C to the charge capacity at 0.2C at 3C versus the discharge capacity at 0.2C. The discharge rate (%) was calculated by calculating the discharge capacity ratio (percentage%). When both the charge rate and the discharge rate are 80% or more, it can be evaluated that the charge / discharge rate characteristics are good. The evaluation results at this time were determined as follows, and the evaluation results of the charge / discharge rate characteristics are also shown in Table 4.
◎: Both the charge rate and the discharge rate are 80% or more ○: At least one of the charge rate and the discharge rate is less than 80% ×: Both the charge rate and the discharge rate are less than 80%

  In the measurement conditions, “1C” indicates a current value at which discharge is completed in one hour after constant current discharge of a cell having a certain electric capacity. For example, “0.1 C” is a current value at which discharge is completed over 10 hours, and 10 C is a current value at which discharge is completed over 0.1 hours.

5.6. Examples 11 to 15 and Comparative Example 2
The composition for electrical storage devices shown in Table 4 was produced like Example 10 except having mix | blended each component shown in Table 4 with the use ratio shown in Table 4. FIG. About the composition for electrical storage devices obtained in this way, toluene insoluble content was measured by the same method as “5.1.1. Synthesis Example 1”, and the results are also shown in Table 4. Moreover, it calculated | required similarly to the said Example 1 about the ionic functional group amount Ma (mmol) of a polymer particle (A), and it showed in Table 4 together.

As is apparent from Table 3 above, the electricity storage device (lithium ion battery) including the separator having the protective film according to the present invention shown in Examples 1 to 9 has a remaining capacity after the durability test and a suppression of an increase in resistance. It was excellent. On the other hand, in Comparative Example 1, an electricity storage device that satisfies both the good remaining capacity and the suppression of the resistance increase rate was not obtained. The reason for this is considered to be that the metal compound and the polymer particles or the water-soluble polymer form a cross-link, thereby exhibiting the above effect.

  As is clear from Table 4 above, the electrode produced using the composition for an electricity storage device according to the present invention shown in Examples 10 to 15 is an electricity storage device (lithium ion battery), which is an adhesive between the protective film and the electrode. It was confirmed that the chargeability / discharge cycle characteristics and charge / discharge rate characteristics were good. On the other hand, in Comparative Example 2, an electricity storage device having good adhesion, charge / discharge cycle characteristics, and charge / discharge rate characteristics was not obtained. The reason for this is considered to be that the metal compound and the polymer particles or the water-soluble polymer form a cross-link, thereby exhibiting the above effect.

  The present invention is not limited to the above embodiment, and various modifications can be made. The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objects and effects). The present invention also includes a configuration in which a non-essential part of the configuration described in the above embodiment is replaced with another configuration. Furthermore, the present invention includes a configuration that achieves the same effects as the configuration described in the above embodiment or a configuration that can achieve the same object. Furthermore, the present invention includes a configuration obtained by adding a known technique to the configuration described in the above embodiment.

  1, 2, 3 ... Electric storage device 10, 110, 210 ... Positive electrode, 12, 112, 212 ... Positive electrode current collector, 14, 114, 214 ... Positive electrode active material layer, 20, 120, 220 ... Negative electrode, 22, 122 222, negative electrode current collector, 24, 124, 224 ... negative electrode active material layer, 30, 130, 230 ... protective film, 40, 140, 240 ... electrolyte, 150, 250 ... separator

Claims (21)

Polymer particles (A);
A metal complex salt (B),
A liquid medium (C);
The composition for electrical storage devices containing this.   The composition for electrical storage devices of Claim 1 whose metal contained in the said metal complex salt (B) is a polyvalent metal.   The composition for an electricity storage device according to claim 1 or 2, wherein the metal complex salt (B) contains at least one metal selected from the group consisting of titanium, zirconium, aluminum, tin, and zinc.   The composition for an electricity storage device according to any one of claims 1 to 3, wherein the polymer particles (A) have an ionic functional group.   5. The ionic functional group according to claim 4, wherein the ionic functional group is at least one functional group selected from the group consisting of a sulfo group, a carboxy group, a hydroxyl group, an amino group, a phosphate group, and a salt group thereof. A composition for an electricity storage device.   The amount of ionic functional groups of the polymer particles (A) is Ma mol, and the content of the metal complex salt (B) is Mb mol. Or the composition for electrical storage devices of Claim 5.   The composition for electrical storage devices according to any one of claims 1 to 6, wherein the amount of ionic functional groups per 100 g of the polymer particles (A) is 0.001 to 1.2 mol.   The composition for electrical storage devices as described in any one of Claims 1 thru | or 7 whose toluene insoluble content in 50 degreeC of the said polymer particle (A) is 90% or more.   The said polymer particle (A) contains the polymer particle (A1) which contains less than 15 mass parts of repeating units derived from the compound which has two or more polymerizable unsaturated groups in 100 mass parts. The composition for electrical storage devices as described in any one of Claims 8-9.   The composition for an electrical storage device according to claim 9, wherein the polymer particle (A1) further contains a repeating unit derived from a monomer having a fluorine atom and a repeating unit derived from an unsaturated carboxylic acid. .   The polymer particle (A1) is a repeating unit derived from an unsaturated carboxylic acid, a repeating unit derived from an unsaturated carboxylic acid ester, a repeating unit derived from an aromatic vinyl compound, and a repeating derived from a conjugated diene compound. The composition for electrical storage devices of Claim 9 which further contains a unit.   The polymer particles (A) contain polymer particles (A2) containing 20 to 100 parts by mass of a repeating unit derived from a compound having two or more polymerizable unsaturated groups in 100 parts by mass. The composition for electrical storage devices as described in any one of Claims 1 thru | or 11. The polymer particle (A2) is a repeating unit derived from an unsaturated carboxylic acid ester (excluding a compound having two or more polymerizable unsaturated groups) and an aromatic vinyl compound (two or more polymerizable unsaturated groups). The composition for electrical storage devices according to claim 12, further comprising at least one of repeating units derived from (1).   The compound having two or more polymerizable unsaturated groups is at least one compound selected from the group consisting of polyfunctional (meth) acrylic acid esters and aromatic polyfunctional vinyl compounds. The composition for electrical storage devices as described in any one of Claims 1-3.   The slurry for electrical storage devices containing the composition for electrical storage devices as described in any one of Claims 1 thru | or 14, and an inorganic filler.   The slurry for an electricity storage device according to claim 15, wherein the inorganic filler is at least one particle selected from the group consisting of silica, titanium oxide, aluminum oxide, zirconium oxide, and magnesium oxide.   The separator for electrical storage devices which equips the surface with the layer formed by apply | coating and drying the slurry for electrical storage devices of Claim 15 or Claim 16.   An electricity storage device comprising the electricity storage device separator according to claim 17.   The slurry for electrical storage devices containing the composition for electrical storage devices as described in any one of Claims 1 thru | or 14, and an active material.   An electricity storage device electrode comprising: a current collector; and a layer formed by applying and drying the slurry for an electricity storage device according to claim 19 on a surface of the current collector. An electricity storage device comprising the electrode for an electricity storage device according to claim 20.

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