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WO2018117088A1 - Électrode négative de batterie lithium-ion - Google Patents

Électrode négative de batterie lithium-ion Download PDF

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Publication number
WO2018117088A1
WO2018117088A1 PCT/JP2017/045487 JP2017045487W WO2018117088A1 WO 2018117088 A1 WO2018117088 A1 WO 2018117088A1 JP 2017045487 W JP2017045487 W JP 2017045487W WO 2018117088 A1 WO2018117088 A1 WO 2018117088A1
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Prior art keywords
negative electrode
active material
electrode active
carbon
group
Prior art date
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Ceased
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PCT/JP2017/045487
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English (en)
Japanese (ja)
Inventor
水野　雄介
直史 庄司
大澤　康彦
雄樹 草地
佐藤　一
赤間　弘
堀江　英明
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Nissan Motor Co Ltd
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Nissan Motor Co Ltd
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Publication date
Priority claimed from JP2017238952A external-priority patent/JP7121449B2/ja
Application filed by Nissan Motor Co Ltd filed Critical Nissan Motor Co Ltd
Priority to US16/470,613 priority Critical patent/US20200020938A1/en
Priority to EP17883103.8A priority patent/EP3561910B1/fr
Priority to CN201780079038.4A priority patent/CN110114913B/zh
Publication of WO2018117088A1 publication Critical patent/WO2018117088A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/134—Electrodes based on metals, Si or alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/40—Alloys based on alkali metals
    • H01M4/405—Alloys based on lithium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a negative electrode for a lithium ion battery.
  • silicon-based materials such as silicon and silicon compounds
  • carbon materials conventionally used as negative electrode active materials have attracted attention.
  • silicon-based materials such as silicon and silicon compounds
  • the volume change of the material accompanying charge / discharge is large.
  • the silicon-based material is self-destructed by volume change or is easily peeled off from the current collector surface, so that it is difficult to improve cycle characteristics.
  • Japanese Unexamined Patent Application Publication No. 2016-103337 discloses a lithium ion in which expansion of a negative electrode is suppressed by adjusting a mixing ratio of at least one of silicon and a silicon compound and carbon and a particle diameter thereof within a predetermined range.
  • a battery is disclosed.
  • the negative electrode described in Japanese Patent Application Laid-Open No. 2016-103337 uses a binder, if the electrode thickness is too thick, the negative electrode active material is peeled off from the surface of the negative electrode current collector. was there. Moreover, since the proportion of the active material is reduced by the amount of the binder used, there is a problem that the energy density is lowered. In addition, expansion and contraction of silicon (hereinafter also referred to as silicon) and a silicon compound (hereinafter also referred to as silicon compound) are limited by the binder, which may easily cause self-destruction. Furthermore, the effect of suppressing the expansion of the negative electrode during charging is not sufficient, and there is room for further improvement.
  • the present invention has been made in view of the above problems, and an object of the present invention is to provide a negative electrode for a lithium ion battery that is excellent in energy density and cycle characteristics and has little volume change during charging.
  • the inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above problems.
  • the present invention is a negative electrode for a lithium ion battery having a negative electrode active material layer, wherein the negative electrode active material layer is a non-binding of a mixture containing silicon and / or silicon compound particles and carbon-based negative electrode active material particles, respectively.
  • the volume average particle diameter of the silicon and / or silicon compound particles is 0.01 to 10 ⁇ m
  • the volume average particle diameter of the carbon-based negative electrode active material particles is 15 to 50 ⁇ m, and is included in the mixture.
  • the present invention relates to a negative electrode for a lithium ion battery, wherein a mass mixing ratio of a total of silicon and silicon compound particles and carbon-based negative electrode active material particles is 5:95 to 45:55.
  • FIG. 1 is a cross-sectional view schematically showing an example of a negative electrode for a lithium ion battery of the present invention.
  • FIG. 2 is a cross-sectional view schematically showing a state in which particles of silicon and / or silicon compound are expanded by charging in the negative electrode for a lithium ion battery shown in FIG.
  • the negative electrode for a lithium ion battery of the present invention is a negative electrode for a lithium ion battery having a negative electrode active material layer, wherein the negative electrode active material layer includes a mixture of silicon and / or silicon compound particles and carbon-based negative electrode active material particles.
  • the volume average particle diameter of the silicon and / or silicon compound particles is 0.01 to 10 ⁇ m, and the volume average particle diameter of the carbon-based negative electrode active material particles is 15 to 50 ⁇ m.
  • the mass mixing ratio of the total of silicon and silicon compound particles contained in the mixture and the carbon-based negative electrode active material particles is 5:95 to 45:55.
  • the negative electrode for a lithium ion battery of the present invention having such a configuration is excellent in energy density and cycle characteristics, and has a small volume change during charging.
  • FIG. 1 is a cross-sectional view schematically showing an example of a negative electrode for a lithium ion battery of the present invention.
  • a negative electrode active material layer 20 is disposed on a negative electrode current collector 10.
  • the negative electrode active material layer 20 is a non-binding body of a mixture including silicon and / or silicon compound particles 30 and carbon-based negative electrode active material particles 40.
  • the silicon particles may be crystalline silicon particles, amorphous silicon particles, or a mixture thereof.
  • silicon compound particles examples include silicon oxide (SiO x ), carbon-coated silicon oxide (see “Preparation of carbon-coated silicon oxide particles” in Production Example 5), Si—C composite, Si—Al alloy, Si—Li. It is preferably at least one kind of particles selected from the group consisting of alloys, Si—Ni alloys, Si—Fe alloys, Si—Ti alloys, Si—Mn alloys, Si—Cu alloys and Si—Sn alloys.
  • the Si—C composite examples include silicon carbide particles, carbon particles whose surfaces are coated with silicon and / or silicon carbide, and silicon particles whose surfaces are coated with carbon and / or silicon carbide.
  • the polymer compound may be used in combination.
  • the silicon particles whose surface is coated with carbon include silicon compound particles formed by forming a coating layer containing a polymer compound and carbon (conductive material; conductive agent) on the surface of the silicon particles.
  • the polymer compound and the coating layer are the same as those described in the section “Carbon-based negative electrode active material particles” below.
  • Silicon and / or silicon compound particles may be aggregated to form composite particles (that is, secondary particles obtained by aggregation of primary particles).
  • composite particles that is, secondary particles obtained by aggregation of primary particles.
  • Examples include composite particles (secondary particles) in which silicon compound particles (primary particles) in which a coating layer containing a polymer compound and carbon (conductive material; conductive agent) is formed on the surface of silicon particles are aggregated (manufacturing). (See “Preparation of silicon composite particles” in Example 6).
  • Examples of the method for forming the composite particles include a method of mixing primary particles of silicon and / or silicon compound particles with a polymer compound (coating resin) described later.
  • the volume average particle diameter of silicon and / or silicon compound particles is 0.01 to 10 ⁇ m.
  • the thickness is preferably 0.05 to 5.0 ⁇ m, more preferably 0.5 to 2.0 ⁇ m.
  • the volume average particle diameter of silicon and / or silicon compound particles is measured by the following method. When composite particles are formed, the volume average particle diameter (secondary particle diameter) of the composite particles is the volume average particle diameter. As obtained.
  • the particle diameter of the silicon and / or silicon compound particles is smaller than the particle diameter of the carbon-based negative electrode active material particles, and silicon and / or even during expansion in the gaps between the particles of the carbon-based negative electrode active material.
  • the silicon compound particles can enter.
  • silicon and / or silicon compound particles and carbon-based negative electrode active material particles are not composited and exist as respective particles. Silicon and / or silicon compound particles are in the gaps between the carbon-based negative electrode active material particles, and silicon and / or silicon compound particles are expanded in the gaps (expansion is within the gaps). Does not affect layer volume change.
  • silicon and / or silicon compound particles used in the present invention commercially available particles having the above-mentioned volume average particle diameter may be used, or commercially available particles may be used by sieving so as to have a desired volume particle diameter. .
  • Carbon-based negative electrode active material particles include carbon-based materials [for example, graphite, non-graphitizable carbon, amorphous carbon, resin fired bodies (for example, those obtained by firing and carbonizing phenol resin, furan resin, etc.), cokes (for example, Pitch coke, needle coke, petroleum coke, etc.)], or conductive polymers (such as polyacetylene and polypyrrole), metal oxides (titanium oxide and lithium / titanium oxide), and metal alloys (lithium-tin alloy, lithium) -Aluminum alloy, aluminum-manganese alloy and the like) and carbon-based material particles.
  • carbon-based negative electrode active material particles those that do not contain lithium or lithium ions inside may be subjected to a pre-doping treatment in which some or all of the inside contains lithium or lithium ions.
  • the volume average particle diameter of the carbon-based negative electrode active material particles is 15 to 50 ⁇ m.
  • the thickness is preferably 15 to 25 ⁇ m, more preferably 17 to 23 ⁇ m, and still more preferably 18 to 20 ⁇ m.
  • the volume average particle size of silicon and silicon compound particles and carbon-based negative electrode active material particles is the particle size (Dv50) at an integrated value of 50% in the particle size distribution determined by the microtrack method (laser diffraction / scattering method). ).
  • the microtrack method is a method for obtaining a particle size distribution using scattered light obtained by irradiating particles with laser light.
  • the Nikkiso Co., Ltd. microtrack etc. can be used for the measurement of a volume average particle diameter.
  • the negative electrode active material layer is composed of a non-binding body of a mixture containing silicon and / or silicon compound particles and carbon-based negative electrode active material particles.
  • the non-binding body of the mixture means that the silicon and / or silicon compound particles and the carbon-based negative electrode active material particles are not fixed to each other by a binder (also called a binder).
  • the negative electrode active material layer does not contain a binder.
  • a negative electrode active material layer in a conventional lithium ion battery is formed by applying a slurry in which silicon and / or silicon compound particles and carbon-based negative electrode active material particles and a binder are dispersed in a solvent to the surface of a negative electrode current collector or the like. Since the negative electrode active material layer is manufactured by heating and drying, the negative electrode active material layer is hardened with a binder. At this time, the negative electrode active materials are fixed to each other by a binder, and the positions of silicon and / or silicon compound particles and carbon-based negative electrode active material particles are fixed. When the negative electrode active material layer is hardened by the binder, excessive stress is applied to the silicon and / or silicon compound particles due to expansion / contraction during charging / discharging, and self-destructing is likely to occur.
  • the negative electrode active material layer is fixed to the surface of the negative electrode current collector by a binder, the negative electrode active material solidified by the binder by expansion and contraction during the charge and discharge of silicon and / or silicon compound particles The layer may be cracked or the negative electrode active material layer may be peeled off from the surface of the negative electrode current collector.
  • the binder that the negative electrode active material layer does not include is a known solvent-drying type used for binding and fixing negative electrode active material particles to each other and negative electrode active material particles and a current collector. It means a dispersion medium drying type binder for lithium ion batteries, and examples thereof include starch, polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, and styrene-butadiene rubber.
  • binders for lithium ion batteries are used by being dissolved or dispersed in water or an organic solvent, and are dried and solidified by volatilizing a solvent component (or dispersion medium component) to form negative electrode active material particles and negative electrode active materials.
  • a solvent component or dispersion medium component
  • the negative electrode active material particle is a concept including all of silicon and / or silicon compound particles and carbon-based negative electrode active material particles.
  • the components (silicon and / or silicon compound particles and carbon-based negative electrode active material particles) in the negative electrode active material are not bound to each other. Also, the position is not fixed.
  • the volume average particle diameter of the carbon-based negative electrode active material particles is as large as 15 to 50 ⁇ m, and the volume average particle diameter of silicon and / or silicon compound particles is as small as 0.01 to 10 ⁇ m.
  • the silicon and / or silicon compound particles are interposed in the gaps between the carbon-based negative electrode active material particles. It becomes a relationship that particles can enter.
  • carbon-based negative electrode active material particles used in the present invention commercially available carbon-based negative electrode active material particles having the above-mentioned volume average particle diameter may be used, and the commercially available carbon-based negative electrode active material particles have a desired volume particle diameter. Thus, it may be used after sieving.
  • FIG. 2 is a cross-sectional view schematically showing a state in which particles of silicon and / or silicon compound are expanded by charging in the lithium ion battery negative electrode shown in FIG.
  • silicon and / or silicon compound particles 30 can enter the gaps between the carbon-based negative electrode active material particles 40. Since the positions of silicon and / or silicon compound particles are not fixed by the binder, the expanded silicon and / or silicon compound particles 30 are optimal in the gaps between the carbon-based negative electrode active material particles 40. Can fit in any position. Therefore, the expansion amount of silicon and / or silicon compound particles is not directly reflected as the expansion amount of the electrode, and the volume change amount of the entire negative electrode 1 for lithium ion batteries is reduced.
  • the binder does not restrict the expansion and contraction of silicon and / or silicon compound particles during charging and discharging, self-destruction of silicon and / or silicon compound particles can be suppressed. Furthermore, since the negative electrode active material layer constituting the negative electrode for a lithium ion battery according to the present invention is not fixed to the negative electrode current collector surface by a binder, the silicon and / or silicon compound particles are charged / discharged. The negative electrode active material layer does not crack or peel off due to expansion / contraction. Therefore, deterioration of cycle characteristics can be suppressed.
  • the negative electrode for a lithium ion battery of the present invention is excellent in energy density and cycle characteristics.
  • the negative electrode active material layer contains silicon and / or silicon compound particles having a large theoretical capacity, the energy density is excellent.
  • the mass mixing ratio between the total of silicon and silicon compound particles and the carbon-based negative electrode active material particles is 5:95 to 45:55.
  • the mass mixing ratio is outside the range of 5:95 to 45:55, the energy density is insufficient, or the volume expansion during charging of the negative electrode active material layer becomes too large.
  • the mass mixing ratio of the total of silicon and silicon compound particles and the carbon-based negative electrode active material particles is more preferably 5:95 to 30:70.
  • the mass mixing ratio is within the above range, the effect of improving the energy density by silicon and / or silicon compound particles is sufficient.
  • the volume expansion at the time of charge of a negative electrode active material layer does not become large too much.
  • the thickness of the negative electrode active material layer is not particularly limited, but is preferably 100 to 1500 ⁇ m, more preferably 200 to 800 ⁇ m, and further preferably 300 to 500 ⁇ m.
  • the electrode By setting the thickness of the negative electrode active material layer in the above range, the electrode can be thicker than the conventional negative electrode, and the amount of the active material contained in the negative electrode is increased. Furthermore, since the energy density is increased by including silicon and / or silicon compound particles in the negative electrode active material layer, a negative electrode having a high energy density and a high capacity can be obtained.
  • the thickness of the negative electrode active material layer is determined before the negative electrode active material layer is charged or when the negative electrode active material layer is discharged to the value of the electrode potential +0.05 V (vs. Li / Li + ) or less. Of thickness.
  • the carbon-based negative electrode active material particles contained in the negative electrode active material layer may be carbon-based negative electrode active material particles themselves, and a coating resin composition containing a polymer compound on at least a part of the surface of the carbon-based negative electrode active material particles although it may be a carbon-based coated negative electrode active material particle having a coating layer made of a material, it is preferably a carbon-based coated negative electrode active material particle.
  • the volume average particle size is determined by the particle size of the carbon-based negative electrode active material particles themselves that do not include a coating layer made of a coating resin composition. That is, the volume average particle diameter of the carbon-based negative electrode active material particles is determined as the volume average particle diameter of the carbon-based negative electrode active material particles themselves in any case.
  • the ratio of the weight of the polymer compound to the weight of the carbon-based coated negative electrode active material particles is not particularly limited, but is preferably 0.01 to 20% by mass.
  • the coating layer made of the coating resin composition contains a polymer compound. Moreover, the conductive material mentioned later may be further included as needed.
  • the carbon-based negative electrode active material particles have a coating layer made of a coating resin composition containing a polymer compound on at least a part of the surface of the carbon-based negative electrode active material particles. Even if the carbon-based coated negative electrode active material particles are in contact with each other, the coating resin compositions are not irreversibly adhered to each other on the contact surface, and the adhesion is temporary and can be easily loosened by hand. Therefore, the carbon-based coated negative electrode active material particles are not fixed by the coated resin composition. Therefore, the negative electrode active material layer containing the carbon-based coated negative electrode active material particles does not have the carbon-based negative electrode active material particles bound to each other.
  • the negative electrode active material layer is made of a non-binder (whether or not it contains a binder) depends on whether the negative electrode active material layer is completely impregnated in the electrolyte solution. It can be confirmed by observing whether or not it collapses.
  • the shape can be maintained for one minute or longer, but when the negative electrode active material layer is a non-binder containing no binder The shape collapses in less than a minute.
  • polymer compound constituting the coating resin composition examples include thermoplastic resins and thermosetting resins, and preferable ones include acrylic resins, urethane resins, silicone resins, and butadiene resins [styrene-butadiene copolymer resins, Butadiene polymer ⁇ butadiene rubber, liquid polybutadiene, etc. ⁇ ]. These resins are preferable because they form an elastic body and can follow the volume change of the active material.
  • a polymer compound having a liquid absorption rate of 10% or more when immersed in an electrolytic solution and a tensile elongation at break in a saturated liquid absorption state of 10% or more is more preferable.
  • the liquid absorption rate when immersed in the electrolytic solution is obtained by the following formula by measuring the weight of the polymer compound before the immersion in the electrolytic solution and after the immersion.
  • EC ethylene carbonate
  • PC propylene carbonate
  • the electrolytic solution dissolved so as to have a concentration of mol / L) is used.
  • the saturated liquid absorption state refers to a state in which the weight of the polymer compound does not increase even when immersed in the electrolytic solution.
  • the electrolyte solution used when manufacturing a lithium ion battery using the negative electrode for lithium ion batteries of this invention is not limited to the said electrolyte solution, You may use another electrolyte solution.
  • lithium ions can easily permeate the polymer compound, so that the ionic resistance in the negative electrode active material layer can be kept low.
  • the liquid absorption is preferably 20% or more, and more preferably 30% or more.
  • a preferable upper limit value of the liquid absorption is 400%, and a more preferable upper limit value is 300%.
  • the tensile elongation at break in the saturated liquid absorption state was determined by punching the polymer compound into a dumbbell shape and immersing it in an electrolytic solution at 50 ° C. for 3 days in the same manner as the measurement of the liquid absorption rate.
  • the state can be measured according to ASTM D683 (test piece shape Type II).
  • the tensile elongation at break is a value obtained by calculating the elongation until the test piece breaks in the tensile test according to the following formula.
  • the polymer compound When the tensile elongation at break in the saturated liquid absorption state of the polymer compound is 10% or more, the polymer compound has an appropriate flexibility, so that the coating resin is changed by the volume change of the carbon-based negative electrode active material particles during charge and discharge. It becomes easy to suppress that the coating layer which consists of a composition peels.
  • the tensile elongation at break is preferably 20% or more, and more preferably 30% or more.
  • the preferable upper limit value of the tensile elongation at break is 400%, and the more preferable upper limit value is 300%.
  • the acrylic resin is preferably a resin comprising a polymer (A1) having an acrylic monomer (a) as an essential constituent monomer.
  • the polymer (A1) is a monomer composition comprising a monomer (a1) having a carboxyl group or an acid anhydride group as the acrylic monomer (a) and a monomer (a2) represented by the following general formula (1).
  • a polymer is preferred.
  • R 1 represents a hydrogen atom or a methyl group
  • R 2 represents a straight chain having 4 to 12 carbon atoms or a branched alkyl group having 3 to 36 carbon atoms.
  • Monomers (a1) having a carboxyl group or an acid anhydride group include (meth) acrylic acid (a11), monocarboxylic acids having 3 to 15 carbon atoms such as crotonic acid and cinnamic acid; (anhydrous) maleic acid and fumaric acid Dicarboxylic acids having 4 to 24 carbon atoms such as itaconic acid, citraconic acid and mesaconic acid; polycarboxylic acids having a valence of 6 to 24 carbon atoms such as aconitic acid and the like. Can be mentioned. Among these, (meth) acrylic acid (a11) is preferable, and methacrylic acid is more preferable.
  • R 1 represents a hydrogen atom or a methyl group.
  • R 1 is preferably a methyl group.
  • R 2 is preferably a linear or branched alkyl group having 4 to 12 carbon atoms or a branched alkyl group having 13 to 36 carbon atoms.
  • R 2 is a linear or branched alkyl group having 4 to 12 carbon atoms.
  • linear alkyl group having 4 to 12 carbon atoms include a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, Nonyl group, decyl group, undecyl group, dodecyl group can be mentioned.
  • Examples of the branched alkyl group having 4 to 12 carbon atoms include 1-methylpropyl group (sec-butyl group), 2-methylpropyl group, 1,1-dimethylethyl group (tert-butyl group), 1-methylbutyl group, 1 , 1-dimethylpropyl group, 1,2-dimethylpropyl group, 2,2-dimethylpropyl group (neopentyl group), 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group 1,1-dimethylbutyl group, 1,2-dimethylbutyl group, 1,3-dimethylbutyl group, 2,2-dimethylbutyl group, 2,3-dimethylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group 1-methylhexyl group, 2-methylhexyl group, 2-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 1-ethy
  • R 2 is a branched alkyl group having 13 to 36 carbon atoms
  • the branched alkyl group having 13 to 36 carbon atoms include a 1-alkylalkyl group [1-methyldodecyl group, 1-butyleicosyl group, 1-hexyloctadecyl group, 1-octylhexadecyl group, 1-decyltetradecyl group, 1-undecyltridecyl group, etc.], 2-alkylalkyl group [2-methyldodecyl group, 2-hexyloctadecyl group, 2- Octylhexadecyl group, 2-decyltetradecyl group, 2-undecyltridecyl group, 2-dodecylhexadecyl group, 2-tridecylpentadecyl group, 2-decyloctadecyl group, 2-tetrade
  • the polymer (A1) preferably further contains an ester compound (a3) of a monovalent aliphatic alcohol having 1 to 3 carbon atoms and (meth) acrylic acid.
  • Examples of the monovalent aliphatic alcohol having 1 to 3 carbon atoms constituting the ester compound (a3) include methanol, ethanol, 1-propanol and 2-propanol.
  • the content of the ester compound (a3) is preferably 10 to 60% by mass based on the total weight of the polymer (A1) from the viewpoint of suppressing volume change of the carbon-based negative electrode active material particles, and 15 to The content is more preferably 55% by mass, and further preferably 20 to 50% by mass.
  • the polymer (A1) may further contain an anionic monomer salt (a4) having a polymerizable unsaturated double bond and an anionic group.
  • Examples of the structure having a polymerizable unsaturated double bond include a vinyl group, an allyl group, a styryl group, and a (meth) acryloyl group.
  • anionic group examples include a sulfonic acid group and a carboxyl group.
  • An anionic monomer having a polymerizable unsaturated double bond and an anionic group is a compound obtained by a combination thereof, such as vinyl sulfonic acid, allyl sulfonic acid, styrene sulfonic acid and (meth) acrylic acid. It is done.
  • the (meth) acryloyl group means an acryloyl group and / or a methacryloyl group.
  • Examples of the cation constituting the salt (a4) of the anionic monomer include lithium ion, sodium ion, potassium ion and ammonium ion.
  • the content thereof is preferably 0.1 to 15% by mass based on the total weight of the polymer compound from the viewpoint of internal resistance and the like. It is more preferably ⁇ 15% by mass, and further preferably 2-10% by mass.
  • the polymer (A1) preferably contains (meth) acrylic acid (a11) and an ester compound (a21), and more preferably contains an ester compound (a3).
  • methacrylic acid is used as (meth) acrylic acid (a11), 2-ethylhexyl methacrylate is used as ester compound (a21), and methyl methacrylate is used as ester compound (a3).
  • the polymer compound includes (meth) acrylic acid (a11), the monomer (a2), an ester compound (a3) of a monovalent aliphatic alcohol having 1 to 3 carbon atoms and (meth) acrylic acid, and a polymerization used as necessary.
  • a monomer composition comprising a salt (a4) of an anionic monomer having a polymerizable unsaturated double bond and an anionic group, and the monomer (a2) and the (meth) acrylic acid
  • the weight ratio of (a11) [the monomer (a2) / (meth) acrylic acid (a11)] is preferably 10/90 to 90/10.
  • the weight ratio of the monomer (a2) and the (meth) acrylic acid (a11) is 10/90 to 90/10, the polymer obtained by polymerizing the monomer has good adhesion to the carbon-based negative electrode active material particles. It becomes difficult to peel off.
  • the weight ratio is preferably 30/70 to 85/15, and more preferably 40/60 to 70/30.
  • the monomer constituting the polymer (A1) includes a monomer (a1) having a carboxyl group or an acid anhydride group, a monomer (a2) represented by the above general formula (1), a carbon number of 1 to 3
  • a monomer (a2) represented by the above general formula (1) a carbon number of 1 to 3
  • the ester compound (a3) of a monovalent aliphatic alcohol of (meth) acrylic acid and an anionic monomer salt (a4) having a polymerizable unsaturated double bond and an anionic group As long as the physical properties of the coalescence (A1) are not impaired, the monomer (a1), the monomer (a2) represented by the general formula (1), a monovalent aliphatic alcohol having 1 to 3 carbon atoms and (meth) acrylic
  • a radical polymerizable monomer (a5) that can be copolymerized with an ester compound (a3) with an acid may be contained.
  • the radical polymerizable monomer (a5) is preferably a monomer not containing active hydrogen, and the following monomers (a51) to (a58) can be used.
  • the monool (i) linear aliphatic monool (tridecyl alcohol, myristyl alcohol, pentadecyl alcohol, cetyl alcohol, heptadecyl alcohol, stearyl alcohol, nonadecyl alcohol, arachidyl alcohol Etc.), (ii) alicyclic monools (cyclopentyl alcohol, cyclohexyl alcohol, cycloheptyl alcohol, cyclooctyl alcohol etc.), (iii) araliphatic monools (benzyl alcohol etc.) and mixtures of two or more thereof Can be mentioned.
  • Nitrogen-containing vinyl compound (a53-1) Amide group-containing vinyl compound (i) (Meth) acrylamide compound having 3 to 30 carbon atoms, such as N, N-dialkyl (1 to 6 carbon atoms) or diaralkyl (carbon number) 7 to 15) (meth) acrylamide (N, N-dimethylacrylamide, N, N-dibenzylacrylamide, etc.), diacetone acrylamide, (Ii) An amide group-containing vinyl compound having 4 to 20 carbon atoms excluding the (meth) acrylamide compound, such as N-methyl-N-vinylacetamide, cyclic amide [pyrrolidone compound (6 to 13 carbon atoms, such as N- Vinylpyrrolidone etc.)].
  • (A53-2) (Meth) acrylate compound (i) Dialkyl (1 to 4 carbon atoms) aminoalkyl (1 to 4 carbon atoms) (meth) acrylate [N, N-dimethylaminoethyl (meth) acrylate, N, N -Diethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, morpholinoethyl (meth) acrylate, etc.] (Ii) Quaternary ammonium group-containing (meth) acrylate ⁇ quaternary amino group-containing (meth) acrylate [N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, etc.]] (Quaternized with a quaternizing agent such as methyl chloride, dimethyl sulfate, benzyl chloride, di
  • A53-3 Heterocycle-containing vinyl compound Pyridine compound (carbon number 7 to 14, for example, 2- or 4-vinylpyridine), imidazole compound (carbon number 5 to 12, for example, N-vinylimidazole), pyrrole compound (carbon number) 6 to 13, for example, N-vinylpyrrole), pyrrolidone compounds (having 6 to 13 carbon atoms, for example, N-vinyl-2-pyrrolidone).
  • Nitrile group-containing vinyl compound A nitrile group-containing vinyl compound having 3 to 15 carbon atoms such as (meth) acrylonitrile, cyanostyrene, cyanoalkyl (1 to 4 carbon atoms) acrylate.
  • Nitro group-containing vinyl compounds (carbon number 8 to 16, for example, nitrostyrene) and the like.
  • Vinyl hydrocarbon (a54-1) Aliphatic vinyl hydrocarbon An olefin having 2 to 18 or more carbon atoms (ethylene, propylene, butene, isobutylene, pentene, heptene, diisobutylene, octene, dodecene, octadecene, etc.), Dienes having 4 to 10 or more carbon atoms (butadiene, isoprene, 1,4-pentadiene, 1,5-hexadiene, 1,7-octadiene, etc.) and the like.
  • (A54-2) Alicyclic vinyl hydrocarbon Cyclic unsaturated compound having 4 to 18 or more carbon atoms, such as cycloalkene (for example, cyclohexene), (di) cycloalkadiene [for example, (di) cyclopentadiene], terpene ( For example, pinene and limonene) and inden.
  • cycloalkene for example, cyclohexene
  • cycloalkadiene for example, (di) cyclopentadiene
  • terpene For example, pinene and limonene
  • Aromatic vinyl hydrocarbon Aromatic unsaturated compounds having 8 to 20 or more carbon atoms, such as styrene, ⁇ -methylstyrene, vinyltoluene, 2,4-dimethylstyrene, ethylstyrene, isopropylstyrene, butyl Styrene, phenyl styrene, cyclohexyl styrene, benzyl styrene.
  • alkenyl ester of aliphatic carboxylic acid mono- or dicarboxylic acid
  • Aromatic vinyl esters [containing 9 to 20 carbon atoms, eg alkenyl esters of aromatic carboxylic acids (mono- or dicar
  • Vinyl ketone Aliphatic vinyl ketone (having 4 to 25 carbon atoms, such as vinyl methyl ketone, vinyl ethyl ketone) and aromatic vinyl ketone (having 9 to 21 carbon atoms, such as vinyl phenyl ketone).
  • Unsaturated dicarboxylic acid diester Unsaturated dicarboxylic acid diester having 4 to 34 carbon atoms such as dialkyl fumarate (two alkyl groups are linear, branched or alicyclic groups having 1 to 22 carbon atoms) ), Dialkyl maleate (two alkyl groups are linear, branched or alicyclic groups having 1 to 22 carbon atoms).
  • (a5) Of those exemplified as (a5) above, (a51), (a52) and (a53) are preferable from the viewpoint of withstand voltage.
  • a monomer (a1) having a carboxyl group or an acid anhydride group a monomer (a2) represented by the general formula (1), a monovalent aliphatic alcohol having 1 to 3 carbon atoms and ( The content of the ester compound (a3) with meth) acrylic acid, the salt (a4) of the anionic monomer having a polymerizable unsaturated double bond and an anionic group, and the radical polymerizable monomer (a5)
  • (a1) is 0.1 to 80% by mass
  • (a2) is 0.1 to 99.9% by mass
  • (a3) is 0 to 60% by mass
  • (a4) is The content is preferably 0 to 15% by mass and (a5) is preferably 0 to 99.8% by mass.
  • the liquid absorbability to the non-aqueous electrolyte is good.
  • the preferable lower limit of the number average molecular weight of the polymer (A1) is 3,000, more preferably 50,000, still more preferably 60,000, and the preferable upper limit is 2,000,000, more preferably 1,500,000. More preferably, it is 1,000,000, particularly preferably 120,000.
  • the number average molecular weight of the polymer (A1) can be determined by gel permeation chromatography (hereinafter abbreviated as GPC) measurement under the following conditions.
  • the polymer (A1) is a known polymerization initiator ⁇ azo initiator [2,2′-azobis (2-methylpropionitrile), 2,2′-azobis (2,4-dimethylvaleronitrile, etc.)] , Peroxide initiators (benzoyl peroxide, di-t-butyl peroxide, lauryl peroxide, etc.) ⁇ by a known polymerization method (bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization, etc.) Can be manufactured.
  • the amount of the polymerization initiator used is preferably 0.01 to 5% by mass, more preferably 0.05 to 2% by mass, based on the total weight of the monomers, from the viewpoint of adjusting the number average molecular weight within a preferable range. More preferably, the content is 0.1 to 1.5% by mass.
  • the polymerization temperature and polymerization time are adjusted according to the type of polymerization initiator, etc., but the polymerization temperature is preferably ⁇ 5 to 150 ° C. (more preferably 30 to 120 ° C.), and the reaction time is preferably 0.1 to The reaction is performed for 50 hours (more preferably 2 to 24 hours).
  • Examples of the solvent used in the solution polymerization include esters (having 2 to 8 carbon atoms such as ethyl acetate and butyl acetate), alcohols (having 1 to 8 carbon atoms such as methanol, ethanol and octanol), hydrocarbons (having carbon atoms). Examples thereof include 4 to 8, such as n-butane, cyclohexane and toluene, and ketones (having 3 to 9 carbon atoms such as methyl ethyl ketone) and amide compounds (such as N, N-dimethylformamide (DMF)).
  • esters having 2 to 8 carbon atoms such as ethyl acetate and butyl acetate
  • alcohols having 1 to 8 carbon atoms such as methanol, ethanol and octanol
  • hydrocarbons having carbon atoms
  • Examples thereof include 4 to 8, such as n-butane, cyclohexane and toluen
  • the amount of the solvent used is preferably 5 to 900% by mass, more preferably 10 to 400% by mass, and still more preferably 30 to 300% based on the total weight of the monomers. % By mass.
  • the monomer concentration is preferably 10 to 95% by mass, more preferably 20 to 90% by mass, and still more preferably 30 to 80% by mass.
  • Examples of the dispersion medium in emulsion polymerization and suspension polymerization include water, alcohol (for example, ethanol), ester (for example, ethyl propionate), light naphtha, and the like.
  • examples of emulsifiers include higher fatty acid (10 to 24 carbon atoms) metal salts (for example, sodium oleate and sodium stearate), higher alcohol (10 to 24 carbon atoms) sulfate metal salt (for example, sodium lauryl sulfate), ethoxylated tetramethyl Examples include decynediol, sodium sulfoethyl methacrylate, and dimethylaminomethyl methacrylate. Furthermore, you may add polyvinyl alcohol, polyvinylpyrrolidone, etc. as a stabilizer.
  • the monomer concentration of the solution or dispersion is preferably 5 to 95% by mass, more preferably 10 to 90% by mass, and still more preferably 15 to 85% by mass.
  • the amount of the polymerization initiator used is preferably 0.01 to 5% by mass, more preferably 0.05 to 2% by mass, based on the total weight of the monomers.
  • chain transfer agents such as mercapto compounds (such as dodecyl mercaptan and n-butyl mercaptan) and / or halogenated hydrocarbons (such as carbon tetrachloride, carbon tetrabromide and benzyl chloride) can be used.
  • mercapto compounds such as dodecyl mercaptan and n-butyl mercaptan
  • halogenated hydrocarbons such as carbon tetrachloride, carbon tetrabromide and benzyl chloride
  • the polymer (A1) contained in the acrylic resin is a crosslinking agent (A ′) having a reactive functional group that reacts the polymer (A1) with a carboxyl group ⁇ preferably a polyepoxy compound (a′1) [polyglycidyl ether].
  • Examples of the method of crosslinking the polymer (A1) using the crosslinking agent (A ′) include a method of crosslinking after coating the carbon-based negative electrode active material particles with the polymer (A1). Specifically, the carbon-based negative electrode in which the carbon-based negative electrode active material particles are coated with the polymer (A1) by mixing the resin solution containing the carbon-based negative electrode active material particles and the polymer (A1) and removing the solvent.
  • a solution containing a crosslinking agent (A ′) is mixed with the carbon-based coated negative electrode active material particles and heated to cause solvent removal and a crosslinking reaction, so that the polymer (A1) Is a method in which a reaction that is crosslinked with a crosslinking agent (A ′) to become a polymer compound is caused on the surface of the carbon-based negative electrode active material particles.
  • the heating temperature is adjusted according to the type of the crosslinking agent, but when the polyepoxy compound (a′1) is used as the crosslinking agent, it is preferably 70 ° C. or higher, and when the polyol compound (a′2) is used. Preferably it is 120 degreeC or more.
  • the urethane resin is a urethane resin (B) obtained by reacting an active hydrogen component and an isocyanate component.
  • the urethane resin (B) has flexibility, coating the carbon-based negative electrode active material particles with the urethane resin (B) can alleviate the volume change of the electrode and suppress the expansion of the electrode.
  • the active hydrogen component (b1) preferably contains at least one selected from the group consisting of polyether diol, polycarbonate diol and polyester diol.
  • Polyether diols include polyoxyethylene glycol (hereinafter abbreviated as PEG), polyoxyethylene oxypropylene block copolymer diol, polyoxyethylene oxytetramethylene block copolymer diol; ethylene glycol, propylene glycol, 1,4-butane Ethylene oxide adducts of low molecular weight glycols such as diol, 1,6-hexamethylene glycol, neopentyl glycol, bis (hydroxymethyl) cyclohexane, 4,4′-bis (2-hydroxyethoxy) -diphenylpropane; number average molecular weight 2 PEG of 1,000 or less and dicarboxylic acid [aliphatic dicarboxylic acid having 4 to 10 carbon atoms (eg, succinic acid, adipic acid, sebacic acid, etc.), aromatic dicarboxylic acid having 8 to 15 carbon atoms (eg, terephthalic acid, 1 or more fused polyethers obtained by
  • the content of the oxyethylene unit is preferably 20% by mass, more preferably 30% by mass or more, and further preferably 40% by mass or more.
  • polyoxypropylene glycol polyoxytetramethylene glycol (hereinafter abbreviated as PTMG), polyoxypropyleneoxytetramethylene block copolymer diol, and the like are also included.
  • PTMG polyoxytetramethylene glycol
  • polyoxypropyleneoxytetramethylene block copolymer diol and the like are also included.
  • PEG polyoxyethyleneoxypropylene block copolymer diol
  • polyoxyethyleneoxytetramethylene block copolymer diol are preferable, and PEG is particularly preferable.
  • polyether diol only one kind of polyether diol may be used, or a mixture of two or more kinds thereof may be used.
  • polycarbonate diol examples include one or more alkylene diols having an alkylene group having 4 to 12, preferably 6 to 10, more preferably 6 to 9 carbon atoms, and a low molecular carbonate compound (for example, By condensing the alkyl group from a dialkyl carbonate having 1 to 6 carbon atoms, an alkylene carbonate having an alkylene group having 2 to 6 carbon atoms, and a diaryl carbonate having an aryl group having 6 to 9 carbon atoms while carrying out a dealcoholization reaction.
  • the polycarbonate polyol for example, polyhexamethylene carbonate diol manufactured is mentioned.
  • polyester diol examples include a condensed polyester diol obtained by reacting a low-molecular diol and / or a polyether diol having a number average molecular weight of 1,000 or less with one or more of the aforementioned dicarboxylic acids, or a lactone having 4 to 12 carbon atoms. And polylactone diols obtained by ring-opening polymerization.
  • the low molecular diol include the low molecular glycols exemplified in the section of the polyether diol.
  • polyether diol having a number average molecular weight of 1,000 or less include polyoxypropylene glycol and PTMG.
  • lactone examples include ⁇ -caprolactone and ⁇ -valerolactone.
  • polyester diol examples include polyethylene adipate diol, polybutylene adipate diol, polyneopentylene adipate diol, poly (3-methyl-1,5-pentylene adipate) diol, polyhexamethylene adipate diol, polycaprolactone diol. And a mixture of two or more of these.
  • the active hydrogen component (b1) may be a mixture of two or more of the polyether diol, polycarbonate diol and polyester diol.
  • the active hydrogen component (b1) contains a high molecular diol (b11) having a number average molecular weight of 2,500 to 15,000 as an essential component.
  • the polymer diol (b11) include the polyether diol, polycarbonate diol, and polyester diol described above.
  • the hardness of the urethane resin (B) is moderately soft, and the strength of the coating formed on the carbon-based negative electrode active material particles is high. Therefore, it is preferable.
  • the number average molecular weight of the polymer diol (b11) is more preferably 3,000 to 12,500, and further preferably 4,000 to 10,000.
  • the number average molecular weight of the polymer diol (b11) can be calculated from the hydroxyl value of the polymer diol.
  • the hydroxyl value can be measured according to the description of JIS K1557-1.
  • the active hydrogen component (b1) has a polymer diol (b11) having a number average molecular weight of 2,500 to 15,000 as an essential component, and a solubility parameter (hereinafter abbreviated as SP value) of the polymer diol (b11). It is desirable to be 8.0 to 12.0 (cal / cm 3 ) 1/2 .
  • the SP value of the polymer diol (b11) is more preferably 8.5 to 11.5 (cal / cm 3 ) 1/2 , and 9.0 to 11.0 (cal / cm 3 ) 1/2 . More desirably.
  • SP value is calculated by Fedors method.
  • the SP value can be expressed by the following equation.
  • ⁇ H represents the heat of vaporization (cal)
  • V represents the molar volume (cm 3 ).
  • ⁇ H and V are the sum of the heat of molar evaporation ( ⁇ H) of the atomic group described in “POLYMER ENGINEERING AND SCIENCE, 1974, Vol. 14, No. 2, ROBERT F. FEDORS.
  • the total molar volume (V) can be used.
  • the SP value of the polymer diol (b11) is preferably 8.0 to 12.0 (cal / cm 3 ) 1/2 from the viewpoint of absorption of the electrolyte solution of the urethane resin (B).
  • the active hydrogen component (b1) has a polymer diol (b11) having a number average molecular weight of 2,500 to 15,000 as an essential component, and the content of the polymer diol (b11) is the weight of the urethane resin (B). From 20 to 80% by mass based on The content of the polymer diol (b11) is more preferably 30 to 70% by mass, and further preferably 40 to 65% by mass.
  • the content of the polymer diol (b11) is 20 to 80% by mass in terms of liquid absorption of the urethane resin (B) electrolyte.
  • the active hydrogen component (b1) includes a polymer diol (b11) having a number average molecular weight of 2,500 to 15,000 and a chain extender (b13) as essential components.
  • chain extender (b13) examples include low-molecular diols having 2 to 10 carbon atoms [eg, ethylene glycol (hereinafter abbreviated as EG), propylene glycol, 1,4-butanediol (hereinafter abbreviated as 1,4-BG).
  • EG ethylene glycol
  • 1,4-BG 1,4-butanediol
  • Diethylene glycol hereinafter abbreviated as DEG
  • DEG Diethylene glycol
  • 1,6-hexamethylene glycol etc .
  • diamines [aliphatic diamines having 2 to 6 carbon atoms (eg, ethylenediamine, 1,2-propylenediamine, etc.), 6 to 6 carbon atoms] 15 alicyclic diamines (eg, isophorone diamine, 4,4′-diaminodicyclohexylmethane, etc.), C6-C15 aromatic diamines (eg, 4,4′-diaminodiphenylmethane, etc.)]; monoalkanolamines (eg, Monoethanolamine etc.); hydrazine or its derivatives (eg adipine) Dihydrazide, etc.) and mixtures of two or more thereof.
  • low molecular diols are preferable, and EG, DEG and 1,4-BG are particularly preferable.
  • a combination of the polymer diol (b11) and the chain extender (b13) a combination of PEG as the polymer diol (b11) and EG as the chain extender (b13), or as a polymer diol (b11)
  • a combination of polycarbonate diol and EG as a chain extender (b13) is preferred.
  • the active hydrogen component (b1) includes a polymer diol (b11) having a number average molecular weight of 2,500 to 15,000, a diol (b12) other than the polymer diol (b11), and a chain extender (b13),
  • the equivalent ratio ⁇ (b11) / (b12) ⁇ of (b11) to (b12) is 10/1 to 30/1, and the equivalent ratio ⁇ (b11) to the total equivalent of (b12) and (b13) ⁇ (B11) / [(b12) + (b13)] ⁇ is preferably 0.9 / 1 to 1.1 / 1.
  • the equivalent ratio ⁇ (b11) / (b12) ⁇ between (b11) and (b12) is more preferably 13/1 to 25/1, and further preferably 15/1 to 20/1.
  • the diol (b12) other than the polymer diol (b11) is not particularly limited as long as it is a diol and is not included in the polymer diol (b11) described above, and specifically, the number average Examples include diols having a molecular weight of less than 2,500 and diols having a number average molecular weight of more than 15,000.
  • diol examples include the polyether diol, polycarbonate diol, and polyester diol described above.
  • a diol other than the polymer diol (b11) and a low molecular diol having 2 to 10 carbon atoms contained in the chain extender (b13) is included in the diol (b12) other than the polymer diol (b11). Shall not.
  • isocyanate component (b2) those conventionally used for polyurethane production can be used.
  • isocyanates include aromatic diisocyanates having 6 to 20 carbon atoms (excluding carbon in the NCO group, the same shall apply hereinafter), aliphatic diisocyanates having 2 to 18 carbon atoms, alicyclic diisocyanates having 4 to 15 carbon atoms, Examples thereof include araliphatic diisocyanates having 8 to 15 carbon atoms, modified products of these diisocyanates (carbodiimide-modified products, urethane-modified products, uretdione-modified products, etc.) and mixtures of two or more thereof.
  • aromatic diisocyanate examples include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate, 2,4′- or 4,4′-diphenylmethane diisocyanate (hereinafter referred to as “the aromatic diisocyanate”).
  • Diphenylmethane diisocyanate is abbreviated as MDI), 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanate And natodiphenylmethane and 1,5-naphthylene diisocyanate.
  • aliphatic diisocyanate examples include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethylcaproate, Examples thereof include bis (2-isocyanatoethyl) carbonate and 2-isocyanatoethyl-2,6-diisocyanatohexanoate.
  • alicyclic diisocyanate examples include isophorone diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, and bis (2-isocyanatoethyl) -4-cyclohexylene-1,2. -Dicarboxylate, 2,5- or 2,6-norbornane diisocyanate and the like.
  • araliphatic diisocyanate examples include m- or p-xylylene diisocyanate, ⁇ , ⁇ , ⁇ ', ⁇ '-tetramethylxylylene diisocyanate, and the like.
  • aromatic diisocyanates and alicyclic diisocyanates, more preferred are aromatic diisocyanates, and particularly preferred is MDI.
  • the equivalent ratio of (b2) / (b11) is preferably 10 to 30/1, more preferably 11 to 28/1. It is. When the ratio of the isocyanate component (b2) exceeds 30 equivalents, a hard coating film is obtained.
  • the equivalent ratio of (b2) / [(b11) + (b13)] is preferably 0.9 to 1.1 / 1, more preferably 0.95 to 1.05 / 1. If it is outside this range, the urethane resin may not have a sufficiently high molecular weight.
  • the number average molecular weight of the urethane resin (B) is preferably 40,000 to 500,000, more preferably 50,000 to 400,000. If the number average molecular weight of the urethane resin (B) is 40,000 or more, sufficient strength as a film can be obtained, and if it is 500,000 or less, the solution viscosity is appropriately adjusted to obtain a uniform film. preferable.
  • the number average molecular weight of the urethane resin (B) is measured by gel permeation chromatography (hereinafter abbreviated as GPC) using dimethylformamide (hereinafter abbreviated as DMF) as a solvent and polyoxypropylene glycol as a standard substance.
  • GPC gel permeation chromatography
  • DMF dimethylformamide
  • the sample concentration may be 0.25% by mass
  • the column stationary phase may be TSKgel SuperH2000, TSKgel SuperH3000, TSKgel SuperH4000 (both manufactured by Tosoh Corporation), and the column temperature may be 40 ° C.
  • Urethane resin (B) can be produced by reacting active hydrogen component (b1) and isocyanate component (b2).
  • the polymer diol (b11) and the chain extender (b13) are used as the active hydrogen component (b1), and the isocyanate component (b2), the polymer diol (b11), and the chain extender (b13) are reacted simultaneously.
  • examples thereof include a shot method and a prepolymer method in which the polymer diol (b11) and the isocyanate component (b2) are reacted first and then the chain extender (b13) is reacted continuously.
  • the urethane resin (B) can be produced in the presence or absence of a solvent inert to the isocyanate group.
  • Suitable solvents in the presence of a solvent include amide solvents [DMF, dimethylacetamide, etc.], sulfoxide solvents (dimethyl sulfoxide, etc.), ketone solvents [methyl ethyl ketone, methyl isobutyl ketone, etc.], aromatic solvents (Toluene, xylene, etc.), ether solvents (dioxane, tetrahydrofuran, etc.), ester solvents (ethyl acetate, butyl acetate, etc.) and mixtures of two or more of these.
  • amide solvents, ketone solvents, aromatic solvents, and mixtures of two or more thereof are preferred.
  • the reaction temperature may be the same as that employed in the known urethanization reaction, preferably 20 to 100 ° C. when a solvent is used, and preferably 20 to 220 when no solvent is used. ° C.
  • a catalyst used in a known polyurethane reaction for example, an amine-based catalyst (such as triethylamine or triethylenediamine) or a tin-based catalyst (such as dibutyltin dilaurate) can be used.
  • an amine-based catalyst such as triethylamine or triethylenediamine
  • a tin-based catalyst such as dibutyltin dilaurate
  • reaction terminator for example, monohydric alcohol (ethanol, isopropyl alcohol, butanol, etc.), monovalent amine (dimethylamine, dibutylamine, etc.), etc.
  • a reaction terminator for example, monohydric alcohol (ethanol, isopropyl alcohol, butanol, etc.), monovalent amine (dimethylamine, dibutylamine, etc.), etc.
  • the urethane resin (B) can be performed with a known production apparatus employed in the industry. When no solvent is used, a manufacturing apparatus such as a kneader or an extruder can be used.
  • the urethane resin (B) thus produced has a solution viscosity measured as a 30% by mass (solid content) DMF solution, preferably 10 to 10,000 poise / 20 ° C., more preferably 100 to 2 1,000 poise / 20 ° C.
  • the silicone resin is a polymer compound having a polydimethylsiloxane skeleton, and a commercially available silicone resin can be used.
  • silicone resins consisting only of organosiloxane bonds, silicone resins modified with alkyd, polyester, epoxy, acrylic, urethane, etc. can be mentioned.
  • the straight silicone resin an appropriately synthesized product or a commercially available product may be used.
  • the commercially available products include KR271, KR272, KR282, KR252, KR255, KR152 (manufactured by Shin-Etsu Chemical Co., Ltd.); SR2400, SR2405, SR2406 (manufactured by Toray Dow Corning Silicone Co., Ltd.).
  • the modified silicone resin an appropriately synthesized product or a commercially available product may be used.
  • the commercially available products include epoxy-modified products (for example, ES-1001N), acrylic-modified silicone (for example, KR-5208), polyester-modified products (for example, KR-5203), alkyd-modified products (for example, KR-206). ), Urethane-modified products (for example, KR-305) (both manufactured by Shin-Etsu Chemical Co., Ltd.); epoxy-modified products (for example, SR2115), alkyd-modified products (for example, SR2110) (all Toray Dow Corning Silicone Co., Ltd.) Company-made).
  • butadiene-based resin a styrene-butadiene copolymer resin and a butadiene polymer are preferable, and a resin commercially available as a butadiene-based latex (made by DIC or the like) can be used.
  • butadiene latex examples include butadiene rubber latex, for example, styrene-butadiene latex such as styrene-butadiene-rubber latex, carboxy-modified styrene-butadiene-rubber latex, styrene-butadiene-vinylpyridine latex, and acrylonitrile-butadiene rubber latex.
  • styrene-butadiene latex such as styrene-butadiene-rubber latex, carboxy-modified styrene-butadiene-rubber latex, styrene-butadiene-vinylpyridine latex, and acrylonitrile-butadiene rubber latex.
  • acrylonitrile-butadiene latex such as carboxy-modified acrylonitrile-butadiene rubber latex and acrylate-butadiene rubber latex.
  • butadiene polymer a cured product of a resin that is commercially available as liquid polybutadiene can be used.
  • the liquid polybutadiene has at least one functional group selected from an epoxy group, a carboxyl group, and a hydroxyl group, contains 1,4-butadiene unit in an amount of 40% by mass or more, preferably 70% by mass or more, and the remainder of the repeating unit Is preferably composed of 1,2-butadiene, but may also contain monomers other than butadiene such as ⁇ -methylstyrene and styrene.
  • a number average molecular weight of 500 to 10,000, preferably 1,000 to 5,000 is suitably used.
  • liquid polybutadiene epoxidized polybutadiene in which an epoxy group is introduced into the liquid polybutadiene resin by a modifier or the like is particularly suitable.
  • Epoxide registered trademark
  • PB4700 and 3600 above, manufactured by Daicel Chemical Industries
  • JP-100, JP-200 above, manufactured by Nippon Soda Co., Ltd.
  • Ricon657 Clay Valley
  • BF-1000 manufactured by Asahi Denka Co., Ltd.
  • Bremmer CP manufactured by NOF Corporation
  • the negative electrode active material layer may further contain a conductive material.
  • the conductive material is selected from conductive materials.
  • carbon fibers such as carbon [graphite and carbon black (acetylene black, ketjen black (registered trademark), furnace black, channel black, thermal lamp black, etc.), PAN-based carbon fiber, pitch-based carbon fiber, etc.
  • Carbon nanofibers, carbon nanotubes, and metals [nickel, aluminum, stainless steel (SUS), silver, copper, titanium, and the like] can be used.
  • These conductive materials may be used alone or in combination of two or more. Further, these alloys or metal oxides may be used. From the viewpoint of electrical stability, aluminum, stainless steel, carbon, silver, copper, titanium and a mixture thereof are preferable, silver, aluminum, stainless steel and carbon are more preferable, and carbon is more preferable. Moreover, as these electrically conductive materials, what coated the electroconductive material (metal thing among the above-mentioned electrically conductive materials) by plating etc. around the particulate ceramic material or the resin material may be used. A polypropylene resin kneaded with graphene is also preferable as the conductive material.
  • the average particle diameter of the conductive material is not particularly limited, but is preferably 0.01 to 10 ⁇ m and more preferably 0.02 to 5 ⁇ m from the viewpoint of the electrical characteristics of the negative electrode for a lithium ion battery. Preferably, it is 0.03 to 1 ⁇ m.
  • the “average particle diameter of the conductive material” means the maximum distance L among the distances between any two points on the particle outline.
  • the value of the “average particle diameter of the conductive material” is the particle diameter of particles observed in several to several tens of fields using observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM). A value calculated as an average value shall be adopted.
  • the shape (form) of the conductive material is not limited to the particle form, and may be a form other than the particle form, for example, a fibrous conductive material.
  • Fibrous conductive materials include conductive fibers made by uniformly dispersing highly conductive metal and graphite in synthetic fibers, metal fibers made from metal such as stainless steel, and the surface of organic fibers as metal. And conductive fibers in which the surface of an organic substance is coated with a resin containing a conductive substance.
  • the average fiber diameter of the fibrous conductive material is preferably 0.1 to 20 ⁇ m.
  • the ratio of the weight of the conductive material to the weight of the negative electrode active material is not particularly limited, but is preferably 0 to 10% by mass.
  • the negative electrode for a lithium ion battery of the present invention preferably has a negative electrode active material layer provided on a negative electrode current collector.
  • the negative electrode current collector examples include metal materials such as copper, aluminum, titanium, stainless steel, nickel, and alloys thereof. Of these, aluminum and copper are more preferable, and aluminum is particularly preferable from the viewpoints of weight reduction, corrosion resistance, and high conductivity.
  • the negative electrode current collector may be a current collector made of baked carbon, conductive polymer, conductive glass, or the like, or may be a resin current collector made of a conductive agent and a resin.
  • the shape of the negative electrode current collector is not particularly limited, and may be a sheet-like current collector made of the above material and a deposited layer made of fine particles made of the above material.
  • the thickness of the negative electrode current collector is not particularly limited, but is preferably 10 to 500 ⁇ m.
  • the same conductive material as an optional component of the negative electrode active material layer can be suitably used.
  • the resin constituting the resin current collector includes polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polycycloolefin (PCO), polyethylene terephthalate (PET), polyether nitrile (PEN), polytetra Fluoroethylene (PTFE), styrene butadiene rubber (SBR), polyacrylonitrile (PAN), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVdF), epoxy resin, silicone resin or a mixture thereof Is mentioned.
  • PE polyethylene
  • PP polypropylene
  • PMP polymethylpentene
  • PCO polycycloolefin
  • PET polyethylene terephthalate
  • PEN polyether nitrile
  • PTFE polytetra Fluoroethylene
  • SBR styrene butadiene rubber
  • PAN polyacrylonitrile
  • PMA polymethyl acrylate
  • PMMA polymethyl methacrylate
  • polyethylene (PE), polypropylene (PP), polymethylpentene (PMP) and polycycloolefin (PCO) are preferable, and polyethylene (PE), polypropylene (PP) and polymethylpentene are more preferable. (PMP).
  • the negative electrode for a lithium ion battery of the present invention can be produced, for example, by forming a negative electrode active material layer on a negative electrode current collector and applying pressure or the like as necessary.
  • a negative electrode active material layer on a negative electrode current collector for example, silicon and / or silicon compound particles and carbon-based negative electrode active material particles are dispersed at a concentration of 30 to 60% by mass based on the weight of the solvent.
  • the applied dispersion is applied to the negative electrode current collector with a coating device such as a bar coater, then the non-woven fabric is left on the active material to absorb the liquid, etc., and the solvent is removed. The method of doing is mentioned.
  • the negative electrode active material layer obtained by drying the dispersion serving as the negative electrode active material layer does not need to be formed directly on the negative electrode current collector.
  • the dispersion is applied to the surface of an aramid separator or the like and dried.
  • the negative electrode for a lithium ion battery of the present invention can also be produced by laminating the layered product (negative electrode active material layer) obtained on the negative electrode current collector.
  • the silicon and / or silicon compound particles used for preparing the dispersion are those having a volume average particle size of 0.01 to 10 ⁇ m, and the carbon-based negative electrode active material particles have a volume average particle size of 15 to 50 ⁇ m. By using what is this, a negative electrode active material layer can be formed.
  • the carbon-based negative electrode active material particles are used as the carbon-based negative electrode active material particles, for example, the carbon-based negative electrode active material particles are placed in a universal mixer and stirred at 30 to 50 rpm. The molecular solution is dropped and mixed over 1 to 90 minutes, and further a conductive material is mixed as necessary. The temperature is raised to 50 to 200 ° C. with stirring, and the pressure is reduced to 0.007 to 0.04 MPa. It can be obtained by holding for a minute.
  • the solvent examples include 1-methyl-2-pyrrolidone, methyl ethyl ketone, N, N-dimethylformamide (DMF), dimethylacetamide, N, N-dimethylaminopropylamine and tetrahydrofuran, a nonaqueous electrolyte solution described later, and a nonaqueous solution described below.
  • a solvent etc. are mentioned.
  • a counter electrode is combined and housed in a cell container together with a separator, and a non-aqueous electrolyte is injected if necessary. It can be manufactured by a sealing method or the like.
  • a positive electrode active material layer made of the positive electrode active material is formed on the other surface of the negative electrode current collector. It is also possible to produce a bipolar electrode, stack the bipolar electrode with a separator and store it in a cell container, inject a non-aqueous electrolyte if necessary, and seal the cell container.
  • the electrode (positive electrode) that is the counter electrode of the negative electrode for a lithium ion battery of the present invention a positive electrode used for a known lithium ion battery can be used.
  • separators examples include polyethylene or polypropylene porous films, laminated films of porous polyethylene films and porous polypropylene films, non-woven fabrics made of synthetic fibers (polyester fibers, aramid fibers, etc.) or glass fibers, and their surfaces.
  • Known separators for lithium ion batteries such as those having ceramic fine particles such as silica, alumina and titania attached thereto can be mentioned.
  • non-aqueous electrolyte a non-aqueous electrolyte containing an electrolyte and a non-aqueous solvent used in the production of a lithium ion battery can be used.
  • electrolyte those used in known electrolyte solutions can be used, and preferable examples include lithium salt electrolytes of inorganic acids such as LiPF 6 , LiBF 4 , LiSbF 6 , LiAsF 6 and LiClO 4 , Fluorine such as Li (FSO 2 ) 2 N (abbreviated as LiFSI), Li (CF 3 SO 2 ) 2 N (abbreviated as LiTFSI) and Li (C 2 F 5 SO 2 ) 2 N (abbreviated as LiBETI) Examples thereof include sulfonylimide electrolytes having atoms, and sulfonylmethide electrolytes having fluorine atoms such as LiC (CF 3 SO 2 ) 3 (abbreviated as LiTFSM).
  • LiFSI Li (CF 3 SO 2 ) 2 N
  • LiTFSI Li (CF 3 SO 2 ) 2 N
  • LiBETI Li (C 2 F 5 SO 2 ) 2 N
  • the electrolyte concentration of the non-aqueous electrolyte is not particularly limited, but is preferably 0.1 to 5 mol / L, and preferably 0.5 to 4 mol / L from the viewpoints of the handleability of the electrolyte and the battery capacity. Is more preferably 1 to 3 mol / L.
  • non-aqueous solvent those used in known non-aqueous electrolytes can be used, for example, lactone compounds, cyclic or chain carbonates, chain carboxylates, cyclic or chain ethers, phosphate esters. , Nitrile compounds, amide compounds, sulfones and the like and mixtures thereof.
  • lactone compound examples include 5-membered rings (such as ⁇ -butyrolactone and ⁇ -valerolactone) and 6-membered lactone compounds (such as ⁇ -valerolactone).
  • cyclic carbonate examples include propylene carbonate, ethylene carbonate and butylene carbonate.
  • chain carbonate examples include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, methyl-n-propyl carbonate, ethyl-n-propyl carbonate, and di-n-propyl carbonate.
  • chain carboxylic acid ester examples include methyl acetate, ethyl acetate, propyl acetate, and methyl propionate.
  • cyclic ether examples include tetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 1,4-dioxane and the like.
  • chain ether examples include dimethoxymethane and 1,2-dimethoxyethane.
  • phosphate esters include trimethyl phosphate, triethyl phosphate, ethyl dimethyl phosphate, diethyl methyl phosphate, tripropyl phosphate, tributyl phosphate, tri (trifluoromethyl) phosphate, tri (trichloromethyl) phosphate, Tri (trifluoroethyl) phosphate, tri (triperfluoroethyl) phosphate, 2-ethoxy-1,3,2-dioxaphosphoran-2-one, 2-trifluoroethoxy-1,3,2- Examples include dioxaphospholan-2-one and 2-methoxyethoxy-1,3,2-dioxaphosphoran-2-one.
  • nitrile compounds include acetonitrile.
  • amide compound examples include N, N-dimethylformamide (hereinafter also referred to as DMF).
  • sulfone include chain sulfones such as dimethyl sulfone and diethyl sulfone, and cyclic sulfones such as sulfolane.
  • the non-aqueous solvent may be used alone or in combination of two or more.
  • lactone compounds Among nonaqueous solvents, lactone compounds, cyclic carbonates, chain carbonates, and phosphates are preferable from the viewpoint of battery output and charge / discharge cycle characteristics. More preferred are lactone compounds, cyclic carbonates and chain carbonates, and particularly preferred are cyclic carbonates or a mixture of cyclic carbonates and chain carbonates. Most preferred is a mixture of ethylene carbonate (EC) and propylene carbonate (PC), a mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC), or a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC). It is.
  • EC ethylene carbonate
  • PC propylene carbonate
  • DMC dimethyl carbonate
  • DEC diethyl carbonate
  • a carbon precursor 10 parts by weight of synthetic mesophase pitch AR ⁇ MPH [Mitsubishi Gas Chemical Co., Ltd.] and 90 parts by weight of polymethylpentene TPX RT18 [Mitsui Chemicals Co., Ltd.] are uniaxially extruded at a barrel temperature of 310 ° C. in a nitrogen atmosphere.
  • a resin composition was prepared by melt-kneading using a machine.
  • the above resin composition was melt-extruded and spun at 390 ° C.
  • the spun resin composition was placed in an electric furnace and held at 270 ° C. for 3 hours under a nitrogen atmosphere to stabilize the carbon precursor.
  • the electric furnace was heated to 500 ° C. over 1 hour and held at 500 ° C. for 1 hour to decompose and remove polymethylpentene.
  • the electric furnace was heated up to 1000 ° C. over 2 hours and held at 1000 ° C. for 30 minutes, and the remaining stabilized carbon precursor was used as a conductive fiber.
  • the average fiber diameter of the carbon fiber was 0.3 ⁇ m
  • the average fiber length was 26 ⁇ m
  • the aspect ratio was 87.
  • the electric conductivity of the carbon fiber was 600 mS / cm.
  • LiPF 6 was dissolved at a ratio of 1 M (mol / L) in a mixed solvent of ethylene carbonate (EC) and propylene carbonate (PC) (volume ratio 1: 1) to prepare an electrolytic solution for a lithium ion secondary battery.
  • EC ethylene carbonate
  • PC propylene carbonate
  • ⁇ Production Example 3 Production of Positive Electrode Active Material Layer> 2 parts by weight of carbon fiber of Production Example 1 and 98 parts by weight of LiNi 0.8 Co 0.15 Al 0.05 O 2 powder as positive electrode active material particles were mixed with the electrolyte of Production Example 2 to prepare an electrolyte slurry.
  • a stainless steel mesh [SUS316 twill woven 2300 mesh manufactured by Sunnet Kogyo Co., Ltd.] is prepared as an electrode manufacturing base material, a ⁇ 15 mm mask is placed on the stainless steel mesh, and an electrolyte solution slurry has a basis weight of 78 mg / cm 2.
  • the positive electrode active material particles and the carbon fibers were fixed on a stainless steel mesh, and a positive electrode for a lithium ion battery was produced.
  • ⁇ Production Example 4 Production of carbon-coated silicon particles> Chemical vapor deposition of silicon particles [Sigma Aldrich Japan Co., Ltd., volume average particle size 1.5 ⁇ m] in a horizontal heating furnace and 1100 ° C./1000 Pa, average residence time of about 2 hours while venting methane gas into the horizontal heating furnace The operation was performed to obtain silicon-based negative electrode active material particles (volume average particle diameter of 1.5 ⁇ m) having a carbon amount of 2 mass% and having a surface coated with carbon.
  • ⁇ Production Example 5 Production of carbon-coated silicon oxide particles> A silicon oxide particle [Sigma Aldrich Japan Co., Ltd., volume average particle diameter 0.01 ⁇ m] is placed in a horizontal heating furnace, and methane gas is passed through the horizontal heating furnace, and the chemistry of 1100 ° C./1000 Pa and average residence time is about 2 hours. Vapor deposition was performed to obtain silicon-based negative electrode active material particles (volume average particle diameter of 0.01 ⁇ m) having a carbon content of 2% by mass and coated with carbon on the surface.
  • ⁇ Production Example 6 Production of silicon composite particles (aggregates of primary particles (secondary particles) in which a coating layer containing a polymer compound and carbon is formed on the surface of silicon particles)> 3 parts of silicon particles [manufactured by Sigma-Aldrich Japan, volume average particle diameter 1.5 ⁇ m] are placed in a universal mixer high speed mixer FS25 [manufactured by Earth Technica Co., Ltd.], and the polymer compound is stirred at room temperature at 720 rpm. 10 parts of a polyacrylic acid resin solution (solvent: ultrapure water, solid content concentration 10%) was added dropwise over 2 minutes, and the mixture was further stirred for 5 minutes.
  • solvent ultrapure water, solid content concentration 10%
  • acetylene black (Denka Co., Ltd., Denka Black (registered trademark)], which is a conductive material (conductive agent), was added while stirring, and stirring was continued for 30 minutes. Thereafter, the pressure was reduced to 0.01 MPa while maintaining the stirring, and then the temperature was raised to 140 ° C. while maintaining the stirring and the degree of vacuum, and the volatile matter was distilled off by maintaining the stirring, the degree of vacuum and the temperature for 8 hours. . The obtained powder was classified with a sieve having an opening of 5 ⁇ m to obtain silicon composite particles (volume average particle size: 9.0 ⁇ m).
  • Example 1 [Preparation of negative electrode active material slurry]
  • Non-graphitizable carbon particles [Carbotron (registered trademark) manufactured by Kureha Battery Materials Japan, Inc., volume average particle diameter 25 ⁇ m] 8.6 parts, silicon particles [Sigma] -Aldrich Japan, volume average particle diameter 2.0 ⁇ m] 0.5 parts and 1 part of carbon fiber produced in Production Example 1 as a conductive material were added, and then a planetary agitation type mixing and kneading apparatus ⁇ Awatori Nerita [Stock Made by Shinki Co., Ltd.] was mixed at 2000 rpm for 1.5 minutes to prepare a negative electrode active material slurry.
  • a planetary agitation type mixing and kneading apparatus ⁇ Awatori Nerita [Stock Made by Shinki Co., Ltd.] was mixed at 2000 rpm for 1.5 minutes to prepare a negative electrode active material slurry.
  • a butyl rubber sheet punched with a ⁇ 15 mm hole for electrode molding is placed on a ⁇ 23 mm aramid nonwoven fabric (model No. 2415R: manufactured by Japan Vilene) so that the hole of the butyl rubber sheet is placed at the center of the aramid nonwoven fabric, and the obtained negative electrode active
  • the material slurry is dropped to a weight per unit area of 39.4 mg / cm 2 and suction filtered (reduced pressure), and then pressed at a pressure of 5 MPa for about 10 seconds to form a negative electrode active material layer disposed on the aramid nonwoven fabric.
  • the prepared negative electrode active material layer had a thickness of 500 ⁇ m.
  • Example 2 The silicon particles in Example 1 were changed from 0.5 parts to 1.8 parts of carbon-coated silicon particles produced in Production Example 4, and the carbon particles were changed to non-graphitizable carbon particles [manufactured by Kureha Battery Materials Japan Co., Ltd.
  • a negative electrode active material layer was prepared in the same manner as in Example 1 except that Carbotron (registered trademark), volume average particle diameter 18 ⁇ m] was changed to 7.2 parts, and the electrolyte solution was changed to 89.9 parts to 90 parts.
  • the thickness of the produced negative electrode active material layer was 480 ⁇ m.
  • Example 3 In Example 1, 0.5 part of the silicon particles was changed to 2.7 parts of silicon oxide [Sigma Aldrich Japan, volume average particle diameter 1.5 ⁇ m], and the carbon particles were changed to non-graphitizable carbon particles [Kureha Co., Ltd. Battery Materials Japan Carbotron, volume average particle diameter 22 ⁇ m] was changed to 6.3 parts, and in preparation of the negative electrode active material layer, the basis weight was changed to 78.8 mg / cm 2 , and the electrolyte was 89.9 parts.
  • a negative electrode active material layer was produced in the same manner as in Example 1 except that the content of was changed to 90 parts.
  • the prepared negative electrode active material layer had a thickness of 1000 ⁇ m.
  • the lithium ion battery was produced together with the positive electrode active material layer produced by changing the basis weight in the production of the positive electrode active material layer in Production Example 3 to 156 mg / cm 2 .
  • Example 4 The silicon particle 0.5 part in Example 1 was changed to 4.1 part of the carbon-coated silicon oxide particle produced in Production Example 5, and the carbon particle was changed to a non-graphitizable carbon particle [Kureha Battery Materials Japan Co., Ltd. Carbotron manufactured, volume average particle diameter 15 ⁇ m] was changed to 5.1 parts, and the negative electrode active material layer was prepared in the same manner as in Example 1 except that the basis weight was changed to 7.9 mg / cm 2 in the production of the negative electrode active material layer. Was made. The thickness of the prepared negative electrode active material layer was 100 ⁇ m.
  • the lithium ion battery was produced together with the positive electrode active material layer produced by changing the basis weight in production of the positive electrode active material layer in Production Example 3 to 15.6 mg / cm 2 .
  • Example 5 A negative electrode active material layer was produced in the same manner as in Example 1 except that 0.5 part of the silicon particles in Example 1 was changed to 0.5 part of the silicon composite particles produced in Production Example 6.
  • the prepared negative electrode active material layer had a thickness of 500 ⁇ m.
  • a negative electrode active material layer was prepared in the same manner as in Example 1 except that the amount of silicon particles used in Example 1 was changed to 4.5 parts and the amount of non-graphitizable carbon particles used was changed to 4.5 parts. did.
  • the thickness of the prepared negative electrode active material layer was 440 ⁇ m.
  • Non-graphitizable carbon particles [Carbotron (registered trademark) manufactured by Kureha Battery Materials Japan, Inc., volume average particle diameter 25 ⁇ m] 5.4 parts, silicon particles [Sigma Aldrich] in 85 parts of the electrolyte solution of Production Example 2 Made in Japan, volume average particle diameter 1.5 ⁇ m] 3.6 parts, 1 part of carbon fiber prepared in Production Example 1 as a conductive material, and then added polyvinylidene fluoride (PVdF; from which water was removed during preparation of the negative electrode raw material slurry Binder) (Sigma Aldrich) 5 parts N-methylpyrrolidone solution was added and mixed for 5 minutes at 2000 rpm using a planetary stirring type mixing and kneading device ⁇ Awatori Nerita [Sinky Co., Ltd.] ⁇ .
  • PVdF polyvinylidene fluoride
  • a negative electrode active material slurry was prepared.
  • the obtained negative electrode active material slurry was dropped on a ⁇ 23 mm aramid nonwoven fabric equipped with a ⁇ 15 mm mask so that the basis weight of the slurry would be 39.4 mg / cm 2 and suction filtered (reduced pressure). Subsequently, it was pressed at 5 MPa for 10 seconds and dried at 100 ° C. for 15 minutes to produce a negative electrode active material layer.
  • the thickness of the produced negative electrode active material layer was 400 ⁇ m.
  • lithium ion batteries including the negative electrode for a lithium ion battery of the present invention were produced by the following procedure.
  • the aramid non-woven fabric is peeled off from the prepared negative electrode active material layer, and placed on the copper foil of the laminate cell.
  • Examples 1-2, 5 and Comparative Examples 1-2 100 ⁇ L, in Example 3 200 ⁇ L, and in Example 4 20 ⁇ L.
  • Electrolytic solutions obtained in Production Example 2 were added, separators (5 cm ⁇ 5 cm, thickness 23 ⁇ m, Celgard 2500, made of polypropylene (PP)) were placed on the negative electrode active material layer, and 100 ⁇ L of electrolytic solution was added. did.
  • the stainless steel mesh is peeled off from the positive electrode active material layer corresponding to each example and each comparative example, and disposed so as to face the negative electrode through the separator.
  • Example 1 100 ⁇ L
  • Example 3 200 ⁇ L of electrolyte solution (obtained in Production Example 2) of 20 ⁇ L was added. Thereafter, the positive electrode active material layer was covered with an aluminum foil of a laminate cell, and two sides orthogonal to one side heat-sealed to the tip of the laminate cell were heat-sealed. Thereafter, the laminate cell was sealed by heat-sealing the opening while evacuating the inside of the cell using a vacuum sealer to obtain a lithium ion battery.
  • the lithium ion battery for characteristic evaluation was charged to 4.2 V at a current of 0.1 C up to 4.2 V under a condition of 45 ° C. Evaluation was performed by repeating a charge / discharge process of CC discharge to 2.5 V with a current of 1 C by repeating 50 times with a pause of 10 minutes.
  • the change (thickness increase) of the battery thickness at the first charge was measured using a contact-type film thickness meter [ABS Digimatic Indicator ID-CX manufactured by Mitutoyo Corporation].
  • the amount of change in battery thickness at the time of initial charge is obtained by subtracting the thickness of the battery before the initial charge from the thickness of the battery after the initial charge.
  • the negative electrode for a lithium ion battery of the present invention suppresses expansion of the negative electrode and is excellent in cycle characteristics.
  • the negative electrode for lithium ion batteries of the present invention is particularly useful as a negative electrode for bipolar secondary batteries and lithium ion batteries used for mobile phones, personal computers, hybrid vehicles, and electric vehicles.
  • negative electrode for lithium ion battery 10 negative electrode current collector, 20 negative electrode active material layer, 30 silicon and / or silicon compound particles, 40 Carbon-based negative electrode active material particles.

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Abstract

Le problème décrit par la présente invention est de fournir une électrode négative de batterie lithium-ion qui présente d'excellentes propriétés de cyclage et une excellente densité d'énergie, et peu de changement de volume lors de la charge. La solution selon l'invention porte sur une électrode négative de batterie lithium-ion ayant une couche de matériau actif d'électrode négative, l'électrode négative de batterie lithium-ion étant caractérisée en ce que : la couche de matériau actif d'électrode négative associée comprend un corps non lié d'un mélange contenant des particules de composé de silicium et/ou de silicium et des particules de matériau actif d'électrode négative à base de carbone; le diamètre de particule moyen en volume des particules de composé de silicium et/ou de silicium est de 0,01 à 10 µm; le diamètre de particule moyen en volume des particules de matériau actif d'électrode négative à base de carbone est de 15 à 50 µm; et le rapport de mélange de masse du total des particules de composé de silicium et de silicium contenus dans le mélange aux particules de matériau actif d'électrode négative à base de carbone est de 5:95 à 45:55.
PCT/JP2017/045487 2016-12-20 2017-12-19 Électrode négative de batterie lithium-ion Ceased WO2018117088A1 (fr)

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WO2015137041A1 (fr) * 2014-03-12 2015-09-17 三洋化成工業株式会社 Matériau actif revêtu pour électrode négative à utiliser dans une batterie lithium-ion, bouillie à utiliser dans une batterie lithium-ion, électrode négative à utiliser dans une batterie lithium-ion, batterie lithium-ion et méthode de fabrication de matériau actif revêtu pour électrode négative à utiliser dans une batterie lithium-ion
WO2016158187A1 (fr) * 2015-03-27 2016-10-06 日産自動車株式会社 Électrode pour cellule au lithium-ion, cellule au lithium-ion, et procédé pour fabriquer une électrode pour cellule au lithium-ion
JP2016186914A (ja) * 2015-03-27 2016-10-27 三菱化学株式会社 非水系二次電池負極用複合黒鉛粒子、非水系二次電池用負極及び非水系二次電池

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CN110265721A (zh) * 2018-09-19 2019-09-20 宁德时代新能源科技股份有限公司 锂离子二次电池
WO2022249476A1 (fr) * 2021-05-28 2022-12-01 昭和電工株式会社 Particules composites, matière active d'électrode négative, et batterie secondaire au lithium-ion
CN113991059A (zh) * 2021-11-09 2022-01-28 河南电池研究院有限公司 一种锂离子电池负极极片及其制备方法
CN116387496A (zh) * 2023-06-02 2023-07-04 瑞浦兰钧能源股份有限公司 一种二次电池正极材料、二次电池正极极片及二次电池
CN116387496B (zh) * 2023-06-02 2023-10-31 瑞浦兰钧能源股份有限公司 一种二次电池正极材料、二次电池正极极片及二次电池

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