JP2016035912A - All-solid secondary battery, solid electrolyte composition, battery electrode sheet using the same, battery electrode sheet manufacturing method, and all-solid secondary battery manufacturing method - Google Patents

Abstract

An all-solid-state secondary battery in which an increase in interfacial resistance in an inorganic solid electrolyte is suppressed without being pressurized, good ionic conductivity and binding properties, and storage stability at high temperatures are realized, Provided are a solid electrolyte composition used therefor, a battery electrode sheet using the same, a method for producing a battery electrode sheet, and a method for producing an all-solid secondary battery. An all solid state secondary battery comprising a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer, wherein at least one of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer is provided. An all-solid secondary battery comprising an inorganic solid electrolyte having conductivity of metal ions belonging to Group 1 or Group 2 of the periodic table and a binder composed of a specific polymer compound. [Selection] Figure 1

Description

  The present invention relates to an all-solid secondary battery, a solid electrolyte composition, a battery electrode sheet using the same, a method for producing a battery electrode sheet, and a method for producing an all-solid secondary battery.

Currently, many lithium ion batteries that are widely used use an electrolytic solution. Attempts have been made to replace this electrolytic solution with a solid electrolyte and make all the constituent materials solid. Among them, flame retardant is first mentioned as an advantage of a technique using an inorganic solid electrolyte. A flammable material such as a carbonate-based solvent is used as a medium for the electrolytic solution used in the lithium ion secondary battery. Although various measures have been taken, further measures in preparation for overcharge are desired. As a solution to this problem, an all-solid secondary battery made of an inorganic compound capable of making the electrolyte nonflammable is positioned.
A further advantage of the all-solid-state secondary battery is that it is suitable for increasing the energy density by stacking electrodes. Specifically, a battery having a structure in which an electrode and an electrolyte are directly arranged in series can be obtained. At this time, since the metal package for sealing the battery cell, the copper wire and the bus bar for connecting the battery cell can be omitted, the energy density of the battery is greatly increased. In addition, good compatibility with the positive electrode material capable of increasing the potential is also mentioned as an advantage.

  Because of the above-described advantages, development of an all-solid secondary battery as a next-generation lithium ion secondary battery has been energetically advanced (Non-Patent Document 1). On the other hand, in an inorganic all-solid secondary battery, since the electrolyte is a hard solid, there is also a disadvantage that the liquid electrolyte does not have. For example, the interface resistance between solid particles is increased. In order to improve these points, there is an example in which a specific polymer compound is used as a binder. Specifically, those using butadiene rubber or polyethylene glycol-based resin disclosed in Patent Documents 1 and 2 are representative examples. Or there exists a thing using the fluororesin disclosed by patent documents 3-5.

JP 2011-076792 A JP 2010-106252 A JP 2014-007138 A JP 2012-204114 A JP 2013-114966 A

NEDO Technology Development Organization, Fuel Cell / Hydrogen Technology Development Department, Energy Storage Technology Development Office “NEDO Next-Generation Automotive Storage Battery Technology Development Roadmap 2008” (June 2009)

The increase in the interface resistance in the all-solid secondary battery may be improved accordingly by the resins disclosed in the above patent documents. However, it is expected that the binders made of the polymer compounds disclosed in the above documents cannot satisfy the recent high demand level, and further improvements are desired.
Therefore, the present invention provides an all-solid secondary material in which an increase in interfacial resistance in an inorganic solid electrolyte is suppressed without applying pressure, and good ionic conductivity and binding properties, as well as storage stability at high temperatures are realized. It is an object of the present invention to provide a battery, a solid electrolyte composition used therefor, a battery electrode sheet using the same, a method for producing a battery electrode sheet, and a method for producing an all-solid secondary battery.

The above problem has been solved by the following means.
[1] An all-solid-state secondary battery comprising a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer, wherein at least one of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer is periodic All-solid-state secondary battery comprising an inorganic solid electrolyte having conductivity of metal ions belonging to Group 1 or Group 2 of the Table and a binder composed of a polymer compound satisfying the following conditions (i) and (ii) .
(I) having a repeating unit represented by the following formula (1-1) (ii) having at least one of the following functional group (a)

In the formula, Z ^{11 to} Z ¹⁴ are each independently a hydrogen atom, a chlorine atom, an alkyl group, or a specific fluorine-containing substituent. The specific fluorine-containing substituent is a fluorine atom, a fluoroalkyl group, or a fluoroalkyloxy group. At least one of Z ^{11 to} Z ¹⁴ is a specific fluorine-containing substituent.
Functional group (a)
Carboxyl group, sulfonic acid group, phosphoric acid group, phosphonic acid group, hydroxyl group, thiol group, isocyanate group, oxetane group, epoxy group, dicarboxylic anhydride group, silyl group [2] Among the binders, the above formula (1 The all-solid-state secondary battery as described in [1] in which 80 mass% or more of repeating units represented by -1) are contained.
[3] The specific fluorine-containing substituent is a fluorine atom, —CF ₃ , —CH ₂ CF ₃ , —CF ₂ CF ₃ , —CF ₂ CF ₂ CF ₃ , —OCF _3, —OCF ₂ CF ₃ or —OCF. all-solid secondary battery according to a ₂ CF ₂ CF ₃ (1) or (2).
[4] The all-solid-state secondary battery according to any one of [1] to 3, wherein the binder has a weight average molecular weight of 15,000 to 1,000,000.
[5] The group selected from the functional group (a) is selected from a carboxyl group, a sulfonic acid group, a phosphoric acid group, a phosphonic acid group, a hydroxyl group, a dicarboxylic anhydride group, and a silyl group. 4]. The all-solid-state secondary battery according to any one of 4).
[6] The all-solid secondary battery according to any one of [1] to [5], wherein the inorganic solid electrolyte is an oxide-based inorganic solid electrolyte.
[7] The all solid state secondary battery according to [6], wherein the inorganic solid electrolyte is selected from compounds of the following formula.
・ Li _xa La _ya TiO ₃
xa = 0.3-0.7, ya = 0.3-0.7
・ Li ₇ La ₃ Zr ₂ O ₁₂
・ Li _3.5 Zn _0.25 GeO ₄
LiTi ₂ P ₃ O ₁₂ ,
_{· Li 1 + xb + yb (} Al, Ga) xb (Ti, Ge) 2-xb Si yb P 3-yb O 12
0 ≦ xb ≦ 1, 0 ≦ yb ≦ 1
・ Li ₃ PO ₄
・ LiPON
・ LiPOD
D is Ti, V, Cr, Mn, Fe, Co, Ni, Cu,
Zr, Nb, Mo, Ru, Ag, Ta, W, Pt, and Au
At least one selected from LiAON
A is at least one selected from Si, B, Ge, Al, C and Ga [8] a solid electrolyte composition applied to an all-solid secondary battery, and is a group 1 or group of periodic table A solid electrolyte composition comprising an inorganic solid electrolyte having conductivity of metal ions belonging to Group 2 and a binder composed of a polymer compound satisfying the following conditions (i) and (ii).
(I) having a repeating unit represented by the following formula (1-1) (ii) having at least one of the following functional group (a)

In the formula, Z ^{11 to} Z ¹⁴ are each independently a hydrogen atom, a chlorine atom, an alkyl group, or a specific fluorine-containing substituent. The specific fluorine-containing substituent is a fluorine atom, a fluoroalkyl group, or a fluoroalkyloxy group. At least one of Z ^{11 to} Z ¹⁴ is a specific fluorine-containing substituent.
Functional group (a)
Carboxyl group, sulfonic acid group, phosphoric acid group, phosphonic acid group, hydroxyl group, thiol group, isocyanate group, oxetane group, epoxy group, dicarboxylic anhydride group, silyl group [9] containing dispersion medium [8] The solid electrolyte composition described in 1.
[10] The solid electrolyte composition according to [9], wherein the dispersion medium is selected from alcohol compound solvents, ether compound solvents, amide compound solvents, ketone compound solvents, aromatic compound solvents, aliphatic compound solvents, and nitrile compound solvents. object.
[11] The solid electrolyte composition according to any one of [8] to [10], wherein the binder is contained in an amount of 0.1 to 20 parts by mass with respect to 100 parts by mass of the inorganic solid electrolyte. .
[12] The solid electrolyte composition according to any one of [8] to [11], including a positive electrode active material.
[13] The solid electrolyte composition according to any one of [8] to [12], wherein the inorganic solid electrolyte is an oxide-based inorganic solid electrolyte.
[14] A battery electrode sheet comprising a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer, wherein at least one of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer is periodically controlled. A battery electrode sheet comprising an inorganic solid electrolyte having conductivity of metal ions belonging to Table Group 1 or Group 2 and a binder composed of a polymer compound satisfying the following conditions (i) and (ii).
(I) having a repeating unit represented by the following formula (1-1) (ii) having at least one of the following functional group (a)

In the formula, Z ^{11 to} Z ¹⁴ are each independently a hydrogen atom, a chlorine atom, an alkyl group, or a specific fluorine-containing substituent. The specific fluorine-containing substituent is a fluorine atom, a fluoroalkyl group, or a fluoroalkyloxy group. At least one of Z ^{11 to} Z ¹⁴ is a specific fluorine-containing substituent.
Functional group (a)
Carboxyl group, sulfonic acid group, phosphoric acid group, phosphonic acid group, hydroxyl group, thiol group, isocyanate group, oxetane group, epoxy group, dicarboxylic acid anhydride group, silyl group [15] [8] to [13] The manufacturing method of the electrode sheet for batteries which forms the solid electrolyte composition as described in any one on metal foil.
[16] A method for producing an all-solid secondary battery, comprising producing an all-solid secondary battery via the method for producing an electrode sheet for a battery according to [15].

In this specification, when there are a plurality of substituents or linking groups indicated by a specific symbol, or when a plurality of substituents (the definition of the number of substituents is the same) is specified simultaneously or alternatively, each substitution The groups and the like may be the same as or different from each other. Further, when a plurality of substituents and the like are close to each other, they may be bonded to each other or condensed to form a ring. At this time, a linking group L described later may be incorporated in the ring.
In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

  The all-solid-state secondary battery of the present invention suppresses an increase in interfacial resistance in an inorganic solid electrolyte regardless of pressurization, and realizes its good ionic conductivity and binding properties, and storage stability at high temperatures. Excellent performance. In addition, according to the solid electrolyte composition of the present invention, the battery electrode sheet using the same, the method for manufacturing the battery electrode sheet, and the method for manufacturing the all-solid secondary battery, the all-solid-state battery that exhibits the above-described excellent performance can be obtained. A secondary battery can be suitably manufactured.

It is a longitudinal cross-sectional view which shows typically the all-solid-state lithium ion secondary battery which concerns on preferable embodiment of this invention. It is a longitudinal cross-sectional view which shows typically the testing apparatus utilized in the Example.

  Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be made based on representative embodiments and specific examples, but the present invention is not limited to such embodiments.

FIG. 1 is a longitudinal sectional view schematically showing an all solid state secondary battery (lithium ion secondary battery) according to a preferred embodiment of the present invention. The all-solid-state secondary battery 10 of the present embodiment includes a negative electrode current collector 1, a negative electrode active material layer 2, an inorganic solid electrolyte layer 3, a positive electrode active material layer 4, and a positive electrode current collector 5 in that order as viewed from the negative electrode side. Have in. Each layer is in contact with each other and has a laminated structure. By adopting such a structure, at the time of charging, electrons (e ⁻ ) are supplied to the negative electrode side, and lithium ions (Li ⁺ ) are accumulated therein. On the other hand, at the time of discharge, lithium ions (Li ⁺ ) accumulated in the negative electrode are returned to the positive electrode side, and electrons are supplied to the working part 6. In the example shown in the figure, a light bulb is adopted as the operation part 6 and is turned on by discharge.
In the all solid state secondary battery of the present invention, the specific binder described below is used as a constituent material for the negative electrode active material layer, the positive electrode active material layer, and the inorganic solid electrolyte layer. Especially, it is preferable to use as all the constituent materials of an inorganic solid electrolyte layer, a positive electrode active material layer, and a negative electrode active material layer.

The thicknesses of the positive electrode active material layer 4, the solid electrolyte layer 3, and the negative electrode active material layer 2 are not particularly limited. In consideration of general battery dimensions, 10 to 1,000 μm is preferable, and 20 μm or more and less than 500 μm is more preferable. In the all solid state secondary battery of the present invention, it is more preferable that the thickness of at least one of the positive electrode active material layer 4, the solid electrolyte layer 3, and the negative electrode active material layer 2 is 50 μm or more and less than 500 μm.
In this specification, the positive electrode active material layer and the negative electrode active material layer may be collectively referred to as an electrode layer. Further, the electrode active material used in the present invention includes a positive electrode active material contained in the positive electrode active material layer and a negative electrode active material contained in the negative electrode active material layer. Sometimes referred to as an active material or an electrode active material.

Hereinafter, it demonstrates from the solid electrolyte composition which can be used suitably for manufacture of the all-solid-state secondary battery of this invention.
The solid electrolyte composition of the present invention contains an inorganic solid electrolyte and a specific binder described later.

<Solid electrolyte composition>
(Inorganic solid electrolyte)
The inorganic solid electrolyte is an inorganic solid electrolyte, and the solid electrolyte is a solid electrolyte capable of moving ions inside. From this point of view, it may be referred to as an ion conductive inorganic solid electrolyte in consideration of distinction from an electrolyte salt (supporting electrolyte) described later.
Since it does not contain organic substances (carbon atoms), it is clearly distinguished from organic solid electrolytes (polymer electrolytes typified by PEO and the like, organic electrolyte salts typified by LiTFSI and the like). Further, since the inorganic solid electrolyte is solid in a steady state, it is not dissociated or released into cations and anions. In this respect, it is also clearly distinguished from inorganic electrolyte salts (LiPF ₆ , LiBF ₄ , LiFSI, LiCl, etc.) in which cations and anions are dissociated or liberated in the electrolytic solution or polymer. The inorganic solid electrolyte is not particularly limited as long as it has conductivity of ions of metals belonging to Group 1 or Group 2 of the periodic table, and generally does not have electron conductivity.

  In the present invention, the inorganic solid electrolyte has ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table. As the inorganic solid electrolyte, a solid electrolyte material applied to this type of product can be appropriately selected and used. Typical examples of inorganic solid electrolytes include (i) sulfide-based inorganic solid electrolytes and (ii) oxide-based inorganic solid electrolytes.

(I) Sulfide-based inorganic solid electrolyte The sulfide-based inorganic solid electrolyte contains sulfur (S) and has ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and What has electronic insulation is preferable. The sulfide-based inorganic solid electrolyte preferably contains at least Li, S and P as elements and has lithium ion conductivity. However, depending on the purpose or the case, other than Li, S and P may be used. An element may be included.
For example, a lithium ion conductive inorganic solid electrolyte that satisfies the composition represented by the following general formula (SE) is preferable.

L ^aa _a1 M ^aa _b1 P _c1 S _d1 A ^aa _e1 Formula (SE)

In the general formula (SE), L ^aa represents an element selected from Li, Na, and K, and Li is preferable. M ^aa represents an element selected from B, Zn, Sn, Si, Cu, Ga, Sb, Al, and Ge. Of these, B, Sn, Si, Al, and Ge are preferable, and Sn, Al, and Ge are more preferable. A ^aa represents I, Br, Cl or F, preferably I or Br, and particularly preferably I. a1 to e1 indicate the composition ratio of each element, and a1: b1: c1: d1: e1 satisfies 1 to 12: 0 to 1: 1: 2 to 12: 0 to 5. a1 is further preferably 1 to 9, and more preferably 1.5 to 4. b1 is preferably 0 to 0.5. Further, d1 is preferably 3 to 7, and more preferably 3.25 to 4.5. Further, e1 is preferably 0 to 3, and more preferably 0 to 1.

In the general formula (SE), the composition ratio of L ^aa , M ^aa , P, S and A ^aa is preferably b1 and e1 are 0, more preferably b1 = 0, e1 = 0 and a1, c1 and The ratio of d1 (a1: c1: d1) is a1: c1: d1 = 1-9: 1: 3-7, more preferably b1 = 0, e1 = 0 and a1: c1: d1 = 1.5 ~ 4: 1: 3.25-4.5. As will be described later, the composition ratio of each element can be controlled by adjusting the blending amount of the raw material compound when producing the sulfide-based inorganic solid electrolyte.

The sulfide-based inorganic solid electrolyte may be amorphous (glass) or crystallized (glass ceramic), or only a part may be crystallized. For example, Li—PS—S glass containing Li, P and S, or Li—PS glass glass ceramic containing Li, P and S can be used.
The sulfide-based inorganic solid electrolyte includes [1] lithium sulfide (Li ₂ S) and phosphorus sulfide (for example, diphosphorus pentasulfide (P ₂ S ₅ )), [2] at least one of lithium sulfide, simple phosphorus and simple sulfur, Or [3] It can be produced by a reaction of lithium sulfide, phosphorus sulfide (for example, diphosphorus pentasulfide (P ₂ S ₅ )) and at least one of simple phosphorus and simple sulfur.

The ratio of Li ₂ S to P ₂ S ₅ in the Li—PS glass and the Li—PS glass glass ceramic is a molar ratio of Li ₂ S: P ₂ S ₅ , preferably 65:35 to 35:35. 85:15, more preferably 68:32 to 77:23. By setting the ratio of Li ₂ S to P ₂ S ₅ within this range, the lithium ion conductivity can be increased. Specifically, the lithium ion conductivity can be preferably 1 × 10 ⁻⁴ S / cm or more, more preferably 1 × 10 ⁻³ S / cm or more. Although there is no upper limit, it is practical that it is 1 × 10 ⁻¹ S / cm or less.

Specific examples of the compound include those using a raw material composition containing, for example, Li ₂ S and a sulfide of an element belonging to Group 13 to Group 15. _{Specifically, Li 2 S-P 2 S} 5, Li 2 S-LiI-P 2 S 5, Li 2 S-LiI-Li 2 O-P 2 S 5, Li 2 S-LiBr-P 2 S 5 _{, Li 2 S-Li 2 O} -P 2 S 5, Li 2 S-Li 3 PO 4 -P 2 S 5, Li 2 S-P 2 S 5 -P 2 O 5, Li 2 S-P 2 S 5 _{-SiS 2, Li 2 S-P} 2 S 5 -SnS, Li 2 S-P 2 S 5 -Al 2 S 3, Li 2 S-GeS 2, Li 2 S-GeS 2 -ZnS, Li 2 S-Ga _{2 S 3, Li 2 S-} GeS 2 -Ga 2 S 3, Li 2 S-GeS 2 -P 2 S 5, Li 2 S-GeS 2 -Sb 2 S 5, Li 2 S-GeS 2 -Al 2 S ₃ , Li ₂ S—SiS ₂ , Li ₂ S—Al ₂ S ₃ , Li ₂ S—SiS ₂ —Al _{2 S 3, Li 2 S-} SiS 2 -P 2 S 5, Li 2 S-SiS 2 -P 2 S 5 -LiI, Li 2 S-SiS 2 -LiI, Li 2 S-SiS 2 -Li 4 SiO 4 Li ₂ S—SiS ₂ —Li ₃ PO ₄ , Li ₁₀ GeP ₂ S _{12 and the} like. Among them, Li ₂ S—P ₂ S ₅ , Li ₂ S—GeS ₂ —Ga ₂ S ₃ , Li ₂ S—SiS ₂ —P ₂ S ₅ , Li ₂ S—SiS ₂ —Li ₄ SiO ₄ , Li _{2 S-SiS 2 -Li 3 PO 4} , Li 2 S-LiI-Li 2 O-P 2 S 5, Li 2 S-Li 2 O-P 2 S 5, Li 2 S-Li 3 PO 4 -P 2 S ₅ , since the raw material composition of crystalline, non-crystalline or mixed crystalline and amorphous material composed of Li ₂ S—GeS ₂ —P ₂ S ₅ and Li ₁₀ GeP ₂ S ₁₂ has high lithium ion conductivity preferable. Examples of a method for synthesizing a sulfide solid electrolyte material using such a raw material composition include an amorphization method. Examples of the amorphization method include a mechanical milling method and a melt quenching method, and among them, the mechanical milling method is preferable. This is because processing at room temperature is possible, and the manufacturing process can be simplified.

(Ii) Oxide-based inorganic solid electrolyte An oxide-based solid electrolyte contains oxygen (O), has ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and is an electron What has insulation is preferable.

As specific compound examples, for example, Li _xa La _ya TiO ₃ [xa = 0.3 to 0.7, ya = 0.3 to 0.7] (LLT), Li ₇ La ₃ Zr ₂ O ₁₂ (LLZ) ), Li _3.5 Zn _0.25 GeO ₄ having a LISICON (Lithium super ionic conductor) -type crystal structure, La _0.55 Li _0.35 TiO ₃ having a perovskite-type crystal structure, NASICON (Natmium super ionic concodic concodic concodic concodic concodic concodonic conc) LiTi ₂ P ₃ O ₁₂ having a crystal _{structure, Li 1 + xb + yb (} Al, Ga) xb (Ti, Ge) 2-xb Si yb P 3-yb O 12 ( provided that, 0 ≦ xb ≦ 1,0 ≦ yb ≦ 1) , include _Li 7 _La 3 _Zr 2 _{O 12} or the like having a garnet-type crystal structure It is. Phosphorus compounds containing Li, P and O are also desirable. For example, lithium phosphate (Li ₃ PO ₄ ), LiPON obtained by substituting part of oxygen of lithium phosphate with nitrogen, LiPOD (D is Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb) , Mo, Ru, Ag, Ta, W, Pt, Au, etc.). LiAON (A is at least one selected from Si, B, Ge, Al, C, Ga, etc.) and the like can also be preferably used.
Among them, Li _xa La _ya TiO ₃ [xa = 0.3 to 0.7, ya = 0.3 to 0.7] (LLT) and Li ₇ La ₃ Zr ₂ O ₁₂ (LLZ) are high lithium ions. It is preferable because it has conductivity, is chemically stable, and is easy to handle. These may be used alone or in combination of two or more.

In the present invention, it is particularly preferable to use an oxide-based inorganic solid electrolyte. Since the oxide-based inorganic solid electrolyte generally has a higher hardness, the interface resistance is likely to increase in the all-solid-state secondary battery. By applying the present invention, the effect becomes more prominent. At this time, since the oxide-based inorganic solid electrolyte has an oxygen atom in its structure, it is preferable to use a binder having a high binding property. From this point of view, a group selected from the functional group group (a) (specific functional group (a)) is introduced in the polymer compound forming the binder described later. As a result, the binder is more firmly fixed to the inorganic solid electrolyte particles, and better performance can be obtained in terms of reduction in interface resistance.
It is also preferable to use a sulfide-based inorganic solid electrolyte from the viewpoint of improving ionic conductivity as compared with the case of using an oxide-based inorganic solid electrolyte. The sulfide-based inorganic solid electrolyte is considered to react with a minute amount of moisture in the atmosphere and have a minute amount of polar groups on the surface. Therefore, it is preferable to use a binder having a high binding property with this polar group. From this point of view, a group selected from the functional group group (a) (specific functional group (a)) is introduced in the polymer compound forming the binder described later. As a result, the binder is more firmly fixed to the inorganic solid electrolyte particles, and better performance can be obtained in terms of reduction in interface resistance.
The said inorganic solid electrolyte may be used individually by 1 type, or may be used in combination of 2 or more type.

  The volume average particle diameter of the inorganic solid electrolyte is not particularly limited, but is preferably 0.01 μm or more, and more preferably 0.1 μm or more. As an upper limit, it is preferable that it is 100 micrometers or less, and it is more preferable that it is 50 micrometers or less. In addition, the measurement of the volume average particle diameter of an inorganic solid electrolyte is performed in the following procedures. An inorganic solid electrolyte is prepared by diluting a 1% by weight dispersion in a 20 ml sample bottle using water (heptane in the case of water labile substances). The diluted dispersion sample is irradiated with 1 kHz ultrasonic waves for 10 minutes and used immediately after that. Using this dispersion sample, using a laser diffraction / scattering particle size distribution measuring device LA-920 (trade name, manufactured by HORIBA), data acquisition was performed 50 times using a quartz cell for measurement at a temperature of 25 ° C. Obtain the volume average particle size. For other detailed conditions and the like, refer to the description of JISZ8828: 2013 “Particle Size Analysis—Dynamic Light Scattering Method” as necessary. Five samples are prepared for each level, and the average value is adopted.

The concentration of the inorganic solid electrolyte in the solid electrolyte composition is preferably 50% by mass or more and 100% by mass in 100% by mass of the solid component when considering both the battery performance and the reduction / maintenance effect of the interface resistance. % Or more is more preferable, and 90% by mass or more is particularly preferable. As an upper limit, it is preferable that it is 99.9 mass% or less from the same viewpoint, It is more preferable that it is 99.5 mass% or less, It is especially preferable that it is 99 mass% or less. However, when used together with a positive electrode active material or a negative electrode active material to be described later, the sum is preferably in the above concentration range.
In the present specification, the solid component refers to a component that does not disappear by volatilization or evaporation when a drying treatment is performed at 100 ° C. Typically, it refers to components other than the dispersion medium described below.

(binder)
The binder applied to the present invention is preferably composed of a polymer compound that satisfies the following conditions (i) and (ii).

・ Condition (i)
This condition prescribes having a repeating unit represented by the following formula (1-1).

In the formula, Z ^{11 to} Z ¹⁴ are each independently a hydrogen atom, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), an alkyl group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6; 1 to 3 are particularly preferable), or a specific fluorine-containing substituent. The specific fluorine-containing substituent is a fluorine atom, a fluoroalkyl group, or a fluoroalkyloxy group. At least one of Z ^{11 to} Z ¹⁴ is a specific fluorine-containing substituent.
The fluoroalkyl group preferably has 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 3 carbon atoms. The fluoroalkyloxy group preferably has 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 3 carbon atoms.
The specific fluorine-containing substituent is a fluorine atom, —CF ₃ , —CH ₂ CF ₃ , —CF ₂ CF ₃ , —CF ₂ CF ₂ CF ₃ , —OCF _3, —OCF ₂ CF _3, or —OCF ₂ CF _2. CF ₃ is preferred.
Among them, at least one of Z ^{11 to} Z ¹⁴ is preferably a fluoroalkyl group or a fluoroalkyloxy group, and particularly preferably a fluoroalkyloxy group.
When Z ^{11 to} Z ¹⁴ are groups that may have a substituent, the substituent T described later may be included or a linking group L may be interposed as long as the effects of the present invention are achieved.

  Although the specific example of the repeating unit represented by Formula (1-1) is illustrated below, this invention is not limited and interpreted by this.

・ Condition (ii)
This condition stipulates that the polymer compound constituting the specific binder has at least one of the following functional group group (a).

The group contained in the functional group (a) includes a carboxyl group, a sulfonic acid group (including an ester), a phosphoric acid group (including an ester), a phosphonic acid group (including an ester), a hydroxyl group, and a thiol group (sulfanyl group). ), An isocyanate group, an oxetane group, an epoxy group, a dicarboxylic anhydride group, and a silyl group (preferably having 1 to 18 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 6 carbon atoms). is there. Examples of the silyl group include an alkylsilyl group, an alkoxysilyl group, an arylsilyl group, and an aryloxysilyl group, and among them, an alkoxysilyl group is preferable. The specific functional group (a) selected from the functional group group (a) may be one type selected from the above group or two or more types. In addition, when a sulfonic acid group, a phosphoric acid group, and a phosphonic acid group are ester bodies, the group which comprises ester is an alkyl group (C1-C12 is preferable, 1-6 are more preferable, and 1-3 are especially preferable. ), An alkenyl group (preferably having 2 to 12 carbon atoms, more preferably 2 to 6), an alkynyl group (preferably having 2 to 12 carbon atoms, more preferably 2 to 6), and an aryl group (preferably having 6 to 22 carbon atoms). 6 to 14 are more preferable, and 6 to 10 are particularly preferable.) Or an aralkyl group (C 7 to 23 is preferable, 7 to 15 is more preferable, and 7 to 11 is particularly preferable), and an alkyl group is preferable. It is more preferable that The carboxyl group, phosphoric acid group, phosphonic acid group, and sulfonic acid group may form a salt with any counter ion. Examples of the counter ion include alkali metal cations and quaternary ammonium cations.
The functional group (a) is more preferably selected from a carboxyl group, a sulfonic acid group, a phosphoric acid group, a phosphonic acid group, a hydroxyl group, a dicarboxylic anhydride group, and a silyl group. Particularly preferred are phosphonic acid groups and silyl groups.

  The repeating unit having the functional group (a) is preferably represented by the following formula (2).

In the formula, Z ²¹ and Z ²² are each independently a hydrogen atom, a halogen atom, a cyano group, a methyl group, or an ethyl group.
Z ²³ is a hydrogen atom, a group represented by Z ²¹ , or a group represented by L ¹ -Z ²⁴ .
Z ²⁴ is the functional group (a) described above. L ¹ is a single bond or a linking group L described later, and a preferred range is also synonymous. Note that the linking group L ¹ may be appropriately selected in relation to the effects of the present invention in view of the convenience of synthesis.
L ¹ is, among others, a single bond, a hydrocarbon linking group (preferably an alkylene group), a hetero linking group (preferably O, NR ^N , or CO), or a linkage having 1 to 10 linking atoms in combination of these. Groups are preferred. Alternatively, a linked structure in which an (oligo) alkyleneoxy group (-(Lr-O-) x-: x is preferably an integer of 1 or more and 10,000 or less) is also preferable.
Z ²¹ and Z ²² , Z ²³ and Z ²⁴ may be bonded to each other or condensed to form a ring. Z ^{21 to} Z ²⁴ may further have an arbitrary substituent T within a range that exhibits the effects of the present invention.
The dicarboxylic anhydride group is preferably a group having a structure of the following formulas (2a) and (2b). * Is a bonding position. The CC bond indicated by # corresponds to the CC bond incorporated in the main chain of the formula (2). That is, in the formula (2b), the main chain is included and the dicarboxylic anhydride group is a —CO—O—CO— moiety.

  Although the specific example of the monomer which forms the repeating unit represented by Formula (2) below is shown, this invention is limited to this and is not interpreted. N in the formula is a natural number, preferably 1 to 10,000, more preferably 1 to 8,000, and particularly preferably 1 to 5,000.

  As a method for introducing a functional group, for example, when a polymer having a repeating structure represented by the above formula (1-1) is polymerized, a monomer containing a functional group that forms a repeating unit represented by the above formula (2); The method of copolymerizing is mentioned. Alternatively, the functional group may be introduced into the polymer terminal by polymerizing with a functional group-containing initiator or chain transfer agent, or the functional group may be introduced into the side chain or the terminal by a polymer reaction (for example, the above-described repetition). It can be introduced by reacting maleic anhydride with a polymer having a unit structure, or a different functional group can be introduced by reacting with a side chain functional group). Commercially available functional group-introduced fluororesins may also be used (for example, KYNAR ADX series manufactured by Arkema Co., Ltd.).

  It is preferable that the polymer compound forming the specific binder substantially consists of only the repeating unit represented by any one of the above formulas (1-1) and the repeating unit represented by the above formula (2). For example, when a cyano group is introduced into the functional group portion, a rigid structure is obtained, so that the flexibility is lowered, and since it is not an interacting functional group, it is expected to have a low binding property. Here, “substantially” means that other repeating units may be incorporated within the scope of the effects of the present invention.

  The polymer compound constituting the specific binder preferably has a weight average molecular weight of 15,000 or more. The molecular weight is further preferably 20,000 or more, and more preferably 30,000 or more. The upper limit of the molecular weight is preferably 1,000,000 or less, more preferably 500,000 or less, and further preferably 200,000 or less. When the molecular weight of the binder is within the above range, better binding properties are exhibited and handling properties (manufacturability) are improved.

In the present invention, the molecular weight of the polymer compound (polymer) means a weight average molecular weight unless otherwise specified, and adopts a value measured by gel permeation chromatography (GPC) in terms of the standard sample below. The measuring device and measurement conditions are basically based on the following condition 1 and are allowed to be set to condition 2 depending on the solubility of the sample. However, depending on the polymer type, an appropriate carrier (eluent) and a column suitable for it may be selected and used.
(Condition 1)
Measuring instrument: EcoSEC HLC-8320 (trade name, manufactured by Tosoh Corporation)
Column: Two TOSOH TSKgel Super AWM-Hs are connected Carrier: 10 mM LiBr / N-methylpyrrolidone Measurement temperature: 40 ° C.
Carrier flow rate: 1.0 ml / min
Sample concentration: 0.1% by mass
Detector: RI (refractive index) detector Standard sample: Polystyrene (Condition 2)
Measuring instrument: Same as above Column: TOSOH TSKgel Super HZM-H,
TOSOH TSKgel Super HZ4000,
TOSOH TSKgel Super HZ2000
Carrier: tetrahydrofuran Measurement temperature: 40 ° C
Carrier flow rate: 1.0 ml / min
Sample concentration: 0.1% by mass
Detector: RI (refractive index) detector Standard sample: Polystyrene

Other Conditions The polymer compound forming the binder preferably contains 80% by mass or more of the repeating unit (non-functional group repeating unit) represented by the formula (1-1) in the molecule. The copolymerization ratio of the non-functional group repeating unit is further preferably 85% by mass or more, and more preferably 90% by mass or more. Although there is no upper limit in particular, it is practical that it is 99.9 mass% or less. The copolymerization ratio of the non-functional group repeating unit can be specified by the amount of the monomer blended at the time of synthesizing the polymer compound. In order to measure the copolymerization ratio from the synthesized polymer compound, the ¹³ C-NMR quantitative spectrum (inverse gate decoupling method) of the polymer compound is measured, and the copolymerization ratio is calculated by calculating from the integral ratio. Can be calculated.

In the polymer compound forming the specific binder, the copolymerization ratio of the repeating unit having the functional group (a) (functional group repeating unit) is preferably 0.1% by mass or more, and 0.3% by mass or more. It is more preferable that it is 0.5 mass% or more. As an upper limit, it is preferable that it is 30 mass% or less, It is more preferable that it is 20 mass% or less, It is especially preferable that it is 15 mass% or less.
In addition, the copolymerization ratio of a functional group repeating unit can be specified by the amount of the monomer compounded at the time of synthesizing the polymer compound. In order to measure the copolymerization ratio from the synthesized polymer compound, the ¹³ C-NMR quantitative spectrum (inverse gate decoupling method) of the polymer compound is measured, and the copolymerization ratio is calculated by calculating from the integral ratio. Can be calculated.

It is preferable that the compounding quantity of the binder in a solid electrolyte composition is 0.1 mass part or more with respect to 100 mass parts of said inorganic solid electrolyte (this is included when using an active material), 0.3 mass More preferably, it is more than 0.5 part by weight. As an upper limit, it is preferable that it is 30 mass parts or less, It is more preferable that it is 20 mass parts or less, It is especially preferable that it is 15 mass parts or less.
For the solid electrolyte composition, in the solid content, the binder is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and 0.5% by mass or more. Is particularly preferred. As an upper limit, it is preferable that it is 30 mass% or less, It is more preferable that it is 20 mass% or less, It is especially preferable that it is 15 mass% or less.
By using the binder in the above range, it is possible to more effectively achieve both the adhesion of the inorganic solid electrolyte and the suppression of the interface resistance.
In addition, the binder applied to the present invention may be used in combination with other binders and various additives in addition to the above-mentioned specific polymer compound. The above blending amount is defined as the total amount of the binder, but it is more preferable to look at the amount of the specific polymer compound.

  In an inorganic all-solid secondary battery, since the electrolyte is solid, the interfacial resistance between solid particles increases. It is understood that by using a polymer compound into which a specific functional group according to the present invention is introduced as a binder, not only the binding property between the solid electrolytes but also the active material and the solid electrolyte can be connected. As a result, not only the adhesion to the current collector is improved, but also the contact between the solid electrolytes or between the active material and the solid electrolyte can be secured and the resistance can be reduced. On the other hand, it is understood that the main chain of the polymer compound has a repeating unit containing a specific fluorine-containing substituent and contributes particularly to the improvement of stability.

In addition, in this specification, it uses for the meaning containing the salt and its ion other than the said compound itself about the display of a compound (For example, when attaching | subjecting and attaching | subjecting a compound and an end). In addition, it is meant to include derivatives in which a part thereof is changed, such as introduction of a substituent, within a range where a desired effect is exhibited.
In the present specification, a substituent that does not specify substitution / non-substitution (the same applies to a linking group) means that the group may have an arbitrary substituent. This is also synonymous for compounds that do not specify substitution / non-substitution. Preferred substituents include the following substituent T.

Examples of the substituent T include the following.
An alkyl group (preferably an alkyl group having 1 to 20 carbon atoms, such as methyl, ethyl, isopropyl, t-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.), alkenyl A group (preferably an alkenyl group having 2 to 20 carbon atoms, such as vinyl, allyl, oleyl, etc.), an alkynyl group (preferably an alkynyl group having 2 to 20 carbon atoms, such as ethynyl, butadiynyl, phenylethynyl, etc.), A cycloalkyl group (preferably a cycloalkyl group having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc.), an aryl group (preferably an aryl group having 6 to 26 carbon atoms, for example, Phenyl, 1-naphthyl, 4-methoxyphenyl, -Chlorophenyl, 3-methylphenyl, etc.), a heterocyclic group (preferably a heterocyclic group having 2 to 20 carbon atoms, preferably a 5- or 6-membered heterocycle having at least one oxygen atom, sulfur atom, nitrogen atom) A cyclic group is preferable, for example, 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-oxazolyl, etc., an alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, for example, Methoxy, ethoxy, isopropyloxy, benzyloxy, etc.), aryloxy groups (preferably aryloxy groups having 6 to 26 carbon atoms, such as phenoxy, 1-naphthyloxy, 3-methylphenoxy, 4-methoxyphenoxy, etc.), An alkoxycarbonyl group (preferably an alkoxycarbonyl having 2 to 20 carbon atoms) Nyl groups such as ethoxycarbonyl, 2-ethylhexyloxycarbonyl, etc., aryloxycarbonyl groups (preferably aryloxycarbonyl groups having 6 to 26 carbon atoms such as phenoxycarbonyl, 1-naphthyloxycarbonyl, 3-methylphenoxy) Carbonyl, 4-methoxyphenoxycarbonyl, etc.), an amino group (preferably containing an amino group having 0 to 20 carbon atoms, an alkylamino group, an arylamino group, such as amino, N, N-dimethylamino, N, N— Diethylamino, N-ethylamino, anilino, etc.), a sulfamoyl group (preferably a sulfamoyl group having 0 to 20 carbon atoms, such as N, N-dimethylsulfamoyl, N-phenylsulfamoyl etc.), an acyl group (preferably Is an acyl group having 1 to 20 carbon atoms For example, acetyl, propionyl, butyryl, etc.), aryloyl group (preferably an aryloyl group having 7 to 23 carbon atoms, such as benzoyl), acyloxy group (preferably an acyloxy group having 1 to 20 carbon atoms, such as acetyl Oxy, etc.), aryloyloxy groups (preferably aryloyloxy groups having 7 to 23 carbon atoms, such as benzoyloxy), carbamoyl groups (preferably carbamoyl groups having 1 to 20 carbon atoms, such as N, N -Dimethylcarbamoyl, N-phenylcarbamoyl and the like), acylamino group (preferably an acylamino group having 1 to 20 carbon atoms, such as acetylamino, benzoylamino, etc.), alkylthio group (preferably an alkylthio group having 1 to 20 carbon atoms) For example, methylthio, ethylthio, isop Pyrthio, benzylthio, etc.), arylthio groups (preferably arylthio groups having 6 to 26 carbon atoms such as phenylthio, 1-naphthylthio, 3-methylphenylthio, 4-methoxyphenylthio, etc.), alkylsulfonyl groups (preferably carbon An alkylsulfonyl group having 1 to 20 atoms such as methylsulfonyl and ethylsulfonyl), an arylsulfonyl group (preferably an arylsulfonyl group having 6 to 22 carbon atoms such as benzenesulfonyl), an alkylsilyl group (preferably An alkylsilyl group having 1 to 20 carbon atoms, such as monomethylsilyl, dimethylsilyl, trimethylsilyl, triethylsilyl, etc.), an arylsilyl group (preferably an arylsilyl group having 6 to 42 carbon atoms, such as triphenylsilyl). , Phospho Le group (preferably a phosphate group 0-20 carbon atoms, for ^{example, -OP (= O) (R} P) 2), a phosphonyl group (preferably a phosphonyl group having 0-20 carbon atoms, for example, -P (= ^O) (R _P) 2), a phosphinyl group (preferably a phosphinyl group having 0 to 20 carbon atoms, for example, ^-P (R _P) 2), (meth) acryloyl group, (meth) acryloyloxy group, A hydroxyl group, a cyano group, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.) are mentioned.
In addition, each of the groups listed as the substituent T may be further substituted with the substituent T described above.

When a compound or a substituent / linking group includes an alkyl group / alkylene group, an alkenyl group / alkenylene group, an alkynyl group / alkynylene group, etc., these may be cyclic or linear, and may be linear or branched These may be substituted as described above or may be unsubstituted.
Each substituent defined in the present specification may be substituted via the following linking group L within a range that exhibits the effects of the present invention. For example, the alkyl group / alkylene group, alkenyl group / alkenylene group and the like may further have the following hetero-linking group interposed in the structure.

Examples of the linking group L include a hydrocarbon linking group [an alkylene group having 1 to 10 carbon atoms (more preferably 1 to 6 carbon atoms, still more preferably 1 to 3), an alkenylene group having 2 to 10 carbon atoms (more preferably carbon atoms). 2 to 6, more preferably 2 to 4), an alkynylene group having 2 to 10 carbon atoms (more preferably 2 to 6, more preferably 2 to 4 carbon atoms), and an arylene group having 6 to 22 carbon atoms (more preferably). Is a carbon number 6-10)], hetero linking group [carbonyl group (—CO—), thiocarbonyl group (—CS—), ether group (—O—), thioether group (—S—), imino group (— NR ^N —), an imine linking group (R ^N —N═C <, —N═C (R ^N ) —)], or a combination of these is preferred. In addition, when condensing and forming a ring, the said hydrocarbon coupling group may form the double bond and the triple bond suitably, and may connect. The ring to be formed is preferably a 5-membered ring or a 6-membered ring. As the five-membered ring, a nitrogen-containing five-membered ring is preferable, and examples of the compound forming the ring include pyrrole, imidazole, pyrazole, indazole, indole, benzimidazole, pyrrolidine, imidazolidine, pyrazolidine, indoline, carbazole, or these And derivatives thereof. Examples of the 6-membered ring include piperidine, morpholine, piperazine, and derivatives thereof. Moreover, when an aryl group, a heterocyclic group, etc. are included, they may be monocyclic or condensed and may be similarly substituted or unsubstituted.
^RN is a hydrogen atom or a substituent. Examples of the substituent include an alkyl group (preferably having 1 to 24 carbon atoms, more preferably 1 to 12, more preferably 1 to 6 and particularly preferably 1 to 3), and an alkenyl group (preferably having 2 to 24 carbon atoms and 2 -12 are more preferable, 2-6 are more preferable, 2-3 are particularly preferable, and an alkynyl group (C2-C24 is preferable, 2-12 are more preferable, 2-6 are more preferable, and 2-3 are Particularly preferred), an aralkyl group (preferably 7 to 22 carbon atoms, more preferably 7 to 14 carbon atoms, particularly preferably 7 to 10 carbon atoms), an aryl group (preferably 6 to 22 carbon atoms, more preferably 6 to 14 carbon atoms, and 6 to 6 carbon atoms). 10 is particularly preferred).
^RP is a hydrogen atom, a hydroxyl group, or a substituent. Examples of the substituent include an alkyl group (preferably having 1 to 24 carbon atoms, more preferably 1 to 12, more preferably 1 to 6 and particularly preferably 1 to 3), and an alkenyl group (preferably having 2 to 24 carbon atoms and 2 -12 are more preferable, 2-6 are more preferable, 2-3 are particularly preferable, and an alkynyl group (C2-C24 is preferable, 2-12 are more preferable, 2-6 are more preferable, and 2-3 are Particularly preferred), an aralkyl group (preferably 7 to 22 carbon atoms, more preferably 7 to 14 carbon atoms, particularly preferably 7 to 10 carbon atoms), an aryl group (preferably 6 to 22 carbon atoms, more preferably 6 to 14 carbon atoms, and 6 to 6 carbon atoms). 10 is particularly preferred), an alkoxy group (preferably having 1 to 24 carbon atoms, more preferably 1 to 12, even more preferably 1 to 6 and particularly preferably 1 to 3), an alkenyloxy group (having carbon numbers). To 24, more preferably 2 to 12, more preferably 2 to 6, particularly preferably 2 to 3, and alkynyloxy group (2 to 24 carbon atoms are preferred, 2 to 12 are more preferred, and 2 to 6 are preferred). More preferably, 2 to 3 are particularly preferable), an aralkyloxy group (preferably 7 to 22 carbon atoms, more preferably 7 to 14 carbon atoms, particularly preferably 7 to 10 carbon atoms), an aryloxy group (preferably 6 to 22 carbon atoms, 6 to 14 are more preferable, and 6 to 10 are particularly preferable.
In the present specification, the number of atoms constituting the linking group is preferably 1 to 36, more preferably 1 to 24, still more preferably 1 to 12, and 1 to 6. Is particularly preferred. The number of linking atoms in the linking group is preferably 10 or less, and more preferably 8 or less. The lower limit is 1 or more. The number of connected atoms refers to the minimum number of atoms that are located in a path connecting predetermined structural portions and are involved in the connection. For example, in the case of —CH ₂ —C (═O) —O—, the number of atoms constituting the linking group is 6, but the number of linking atoms is 3.
Specific examples of combinations of linking groups include the following. Oxycarbonyl group (OCO), carbonate group (OCOO), amide group (CONH), urethane group (NHCOO), urea group (NHCONH), (poly) alkyleneoxy group (-(Lr-O) x-), carbonyl ( Poly) oxyalkylene group (—CO— (O—Lr) x —, carbonyl (poly) alkyleneoxy group (—CO— (Lr—O) x—), carbonyloxy (poly) alkyleneoxy group (—COO— ( Lr-O) x -), ( poly) alkyleneimino group ^{(- (Lr-NR N)} x), alkylene (poly) iminoalkylene group ^{(-Lr- (NR N -Lr) x-} ), carbonyl (poly) iminoalkylene group ^{(-CO- (NR N -Lr) x-} ), carbonyl (poly) alkyleneimino group ^{(-CO- (Lr-NR N)} x -), ( poly) S. Group (-(CO-O-Lr) x-,-(O-CO-Lr) x-,-(O-Lr-CO) x-,-(Lr-CO-O) x-,-(Lr -O-CO) x -), ( poly) amide group ^{(- (CO-NR N -Lr} ) x -, - (NR N -CO-Lr) x -, - (NR N -Lr-CO) x- ^{, - (Lr-CO-NR} N) x -, - (Lr-NR N -CO) x-) is located .x is an integer of 1 or more, etc., preferably 1 to 500, more preferably 1 to 100 .
Lr is preferably an alkylene group, an alkenylene group or an alkynylene group. 1-12 are preferable, as for carbon number of Lr, 1-6 are more preferable, and 1-3 are especially preferable. A plurality of Lr, R ^N , R ^P , x, etc. need not be the same. The direction of the linking group is not limited by the above description, and may be understood as appropriate according to a predetermined chemical formula.

(Dispersion medium)
In the solid electrolyte composition of the present invention, a dispersion medium in which the above components are dispersed may be used. Examples of the dispersion medium include a water-soluble organic solvent. Specific examples include the following, which are preferable.
Alcohol compound solvent Methyl alcohol, ethyl alcohol, 1-propyl alcohol, 2-propyl alcohol, 2-butanol, ethylene glycol, propylene glycol, glycerin, 1,6-hexanediol, cyclohexanediol, sorbitol, xylitol, 2-methyl- 2,4-Pentanediol, 1,3-Butanediol, 1,4-Butanediol, etc. Ether compound solvents (including hydroxyl group-containing ether compounds)
Dimethyl ether, diethyl ether, diisopropyl ether, dibutyl ether, t-butyl methyl ether, cyclohexyl methyl ether, anisole, tetrahydrofuran, alkylene glycol alkyl ether (ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol, dipropylene glycol, propylene glycol monomethyl ether Diethylene glycol monomethyl ether, triethylene glycol, polyethylene glycol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, diethylene glycol monobutyl ether, etc.) Amide compound solvent N, N-dimethylform Amide, 1-methyl-2-pyrrolidone, 2-pyrrolidinone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, formamide, N-methylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide , N-methylpropanamide, hexamethylphosphoric triamide, etc.-Ketone compound solvent Acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.-Aromatic compound solvent, benzene, toluene, etc.-Aliphatic compound solvent hexane, heptane, cyclohexane, methylcyclohexane , Octane, pentane, cyclopentane, decane, etc.-Nitrile compound solvent Acetonitrile

  In the present invention, it is particularly preferable to use an ether compound solvent, a ketone compound solvent, an aromatic compound solvent, or an aliphatic compound solvent. The dispersion medium preferably has a boiling point of 50 ° C. or higher, more preferably 80 ° C. or higher at normal pressure (1 atm). The upper limit is preferably 220 ° C. or lower, and more preferably 180 ° C. or lower. The said dispersion medium may be used individually by 1 type, or may be used in combination of 2 or more type.

(Positive electrode active material)
Next, the positive electrode active material used for the solid electrolyte composition (hereinafter also referred to as the positive electrode composition) for forming the positive electrode active material layer of the all-solid-state secondary battery of the present invention will be described.
The positive electrode active material is preferably one that can reversibly insert and release lithium ions. The material is not particularly limited, and may be a transition metal oxide or an element that can be combined with Li such as sulfur. Among these, it is preferable to use a transition metal oxide, and it is more preferable to have one or more elements selected from Co, Ni, Fe, Mn, Cu, and V as a transition metal element.
Specific examples of the transition metal oxide include (MA) a transition metal oxide having a layered rock salt structure, (MB) a transition metal oxide having a spinel structure, (MC) a lithium-containing transition metal phosphate compound, (MD And lithium-containing transition metal halide phosphate compounds, (ME) lithium-containing transition metal silicate compounds, and the like.

(MA) As specific examples of the transition metal oxide having a layered rock salt structure, LiCoO ₂ (lithium cobaltate [LCO]), LiNi ₂ O ₂ (lithium nickelate) LiNi _0.85 Co _0.10 Al _0.05 O ₂ (nickel cobalt lithium aluminum oxide [NCA]), LiNi _0.33 Co _0.33 Mn _0.33 O ₂ (nickel manganese lithium cobalt oxide [NMC]), LiNi _0.5 Mn _0.5 O ₂ (manganese) Lithium nickelate).
(MB) As specific examples of the transition metal oxide having a spinel structure, LiMn ₂ O ₄ (lithium manganate [LMO]), LiCoMnO _4, Li ₂ FeMn ₃ O ₈ , Li ₂ CuMn ₃ O ₈ , Li ₂ CrMn ₃ O _{8 and} Li ₂ NiMn ₃ O ₈ are mentioned.
Examples of (MC) lithium-containing transition metal phosphate compounds include olivine-type iron phosphate salts such as LiFePO ₄ and Li ₃ Fe ₂ (PO ₄ ) ₃ , iron pyrophosphates such as LiFeP ₂ O ₇ , LiCoPO _{4 and the} like. And monoclinic Nasicon type vanadium phosphate salts such as Li ₃ V ₂ (PO ₄ ) ₃ (vanadium lithium phosphate).
The (MD) lithium-containing transition metal halogenated phosphate compound, for _example, Li 2 FePO ₄ F such fluorinated phosphorus iron _salt, Li 2 MnPO ₄ hexafluorophosphate manganese salts such as _F, Li 2 CoPO ₄ F Cobalt fluorophosphates such as
Examples of the (ME) lithium-containing transition metal silicate compound include Li ₂ FeSiO ₄ , Li ₂ MnSiO ₄ , Li ₂ CoSiO _{4, and the} like.

  The volume average particle diameter (sphere conversion average particle diameter) of the positive electrode active material that can be used in the solid electrolyte composition of the present invention is not particularly limited. In addition, 0.1 micrometers-50 micrometers are preferable. In order to make the positive electrode active material have a predetermined particle size, an ordinary pulverizer or classifier may be used. The positive electrode active material obtained by the firing method may be used after being washed with water, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent. The volume average particle size of the positive electrode active material can be measured using a laser diffraction / scattering particle size distribution analyzer LA-920 (trade name, manufactured by HORIBA).

  Although the density | concentration of a positive electrode active material is not specifically limited, 10-90 mass% is preferable in 100 mass% of solid components in a composition for positive electrodes, and 20-80 mass% is more preferable.

  The positive electrode active materials may be used alone or in combination of two or more.

(Negative electrode active material)
Next, the negative electrode active material used for the negative electrode composition of the all solid state secondary battery of the present invention will be described. As the negative electrode active material, those capable of reversibly inserting and releasing lithium ions are preferable. The material is not particularly limited, and is a carbonaceous material, a metal oxide such as tin oxide or silicon oxide, a metal composite oxide, a lithium alloy such as lithium alone or a lithium aluminum alloy, and a lithium such as Sn, Si, or In. And metals capable of forming an alloy. Of these, carbonaceous materials or lithium composite oxides are preferably used from the viewpoint of reliability. In addition, the metal composite oxide is preferably capable of inserting and extracting lithium. The material is not particularly limited, but preferably contains titanium and / or lithium as a constituent component from the viewpoint of high current density charge / discharge characteristics.

  The carbonaceous material used as the negative electrode active material is a material substantially made of carbon. Examples thereof include carbonaceous materials obtained by baking various synthetic resins such as artificial pitches such as petroleum pitch, natural graphite, and vapor-grown graphite, and PAN-based resins and furfuryl alcohol resins. Furthermore, various carbon fibers such as PAN-based carbon fiber, cellulose-based carbon fiber, pitch-based carbon fiber, vapor-grown carbon fiber, dehydrated PVA-based carbon fiber, lignin carbon fiber, glassy carbon fiber, activated carbon fiber, mesophase micro Examples thereof include spheres, graphite whiskers, and flat graphite.

  These carbonaceous materials can be divided into non-graphitizable carbon materials and graphite-based carbon materials depending on the degree of graphitization. Further, the carbonaceous material preferably has the surface spacing, density, and crystallite size described in JP-A-62-222066, JP-A-2-6856, and 3-45473. The carbonaceous material does not need to be a single material, and a mixture of natural graphite and artificial graphite described in JP-A-5-90844, graphite having a coating layer described in JP-A-6-4516, or the like is used. You can also.

  As the metal oxide and metal composite oxide applied as the negative electrode active material, an amorphous oxide is particularly preferable, and chalcogenite, which is a reaction product of a metal element and an element of Group 16 of the periodic table, is also preferably used. It is done. The term “amorphous” as used herein means an X-ray diffraction method using CuKα rays, which has a broad scattering band having an apex in the region of 20 ° to 40 ° in terms of 2θ values, and is a crystalline diffraction line. You may have. The strongest intensity of crystalline diffraction lines seen from 2 ° to 40 ° to 70 ° is 100 times the diffraction line intensity at the peak of the broad scattering band seen from 2 ° to 20 °. It is preferable that it is 5 times or less, and it is particularly preferable not to have a crystalline diffraction line.

Among the group of compounds consisting of the above amorphous oxide and chalcogenide, amorphous metal oxides and chalcogenides are more preferable, and elements of Groups 13 (IIIB) to 15 (VB) of the periodic table are preferable. Particularly preferred are oxides and chalcogenides composed of one kind of Al, Ga, Si, Sn, Ge, Pb, Sb, Bi, or a combination of two or more thereof. Specific examples of preferable amorphous oxides and chalcogenides include, for example, Ga ₂ O ₃ , SiO, GeO, SnO, SnO ₂ , PbO, PbO ₂ , Pb ₂ O ₃ , Pb ₂ O ₄ , Pb ₃ O ₄ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅ , Bi ₂ O ₃ , Bi ₂ O ₄ , SnSiO ₃ , GeS, SnS, SnS ₂ , PbS, PbS ₂ , Sb ₂ S ₃ , Sb ₂ S ₅ , such as SnSiS ₃ may preferably be mentioned. Moreover, these may be a complex oxide with lithium oxide, for example, Li ₂ SnO ₂ .

  The average particle diameter of the negative electrode active material is preferably 0.1 μm to 60 μm. In order to obtain a predetermined particle size, a well-known pulverizer or classifier is used. For example, a mortar, a ball mill, a sand mill, a vibrating ball mill, a satellite ball mill, a planetary ball mill, a swirling air flow type jet mill or a sieve is preferably used. When pulverizing, wet pulverization in the presence of water or an organic solvent such as methanol can be performed as necessary. In order to obtain a desired particle size, classification is preferably performed. The classification method is not particularly limited, and a sieve, an air classifier, or the like can be used as necessary. Classification can be used both dry and wet.

  The chemical formula of the compound obtained by the above firing method can be calculated from an inductively coupled plasma (ICP) emission spectroscopic analysis method as a measurement method, and from a mass difference between powders before and after firing as a simple method.

  Examples of the negative electrode active material that can be used in combination with the amorphous oxide negative electrode active material centering on Sn, Si, and Ge include carbon materials that can occlude and release lithium ions or lithium metal, lithium, lithium alloys, lithium A metal that can be alloyed with is preferable.

  Among these, it is preferable that at least one active material represented by the following formula (A) is included.

Si _xx M _(1-xx) Formula (A)

  In the formula (A), xx represents a number of 0.01 or more and less than 1, and means a mole fraction. M represents a chalcogen element, a metalloid element, an alkali metal element, an alkaline earth metal element, a transition metal element, or a combination thereof.

M is preferably a chalcogen element such as O, S or Se, a metalloid element such as B or Ge, an alkali metal element such as Li or Na, an alkaline earth metal element such as Mg or Ca, Ti, V, It can be selected from transition metal elements such as Mn, Fe, Co, Ni and Cu. Further, a combination of two or more of these elements may be used.
Of these, chalcogen elements and transition metal elements are preferable, and transition metal elements are more preferable. Among the transition metal elements, the first transition metal element is preferable, Ti, V, Mn, Fe, Co, Ni, and Cu are more preferable, and Ti, Mn, Fe, Co, and Ni are particularly preferable.

  xx is preferably from 0.1 to less than 1, more preferably from 0.1 to 0.99, further preferably from 0.2 to 0.98, particularly preferably from 0.3 to 0.95.

It is also preferable that the negative electrode active material contains a titanium atom. More specifically, Li ₄ Ti ₅ O ₁₂ (lithium titanate [LTO]) is excellent in rapid charge / discharge characteristics due to small volume fluctuations during the insertion and release of lithium ions, and the deterioration of the electrodes is suppressed, and the lithium ion secondary This is preferable in that the battery life can be improved.

  Although the density | concentration of a negative electrode active material is not specifically limited, It is preferable that it is 10-80 mass% in 100 mass% of solid components in a solid electrolyte composition, and it is more preferable that it is 20-70 mass%.

  The said negative electrode active material may be used individually by 1 type, or may be used in combination of 2 or more type.

  Moreover, you may make a negative electrode active material layer contain a conductive support agent suitably as needed. As the conductive auxiliary agent, those described below can be used.

(Conductive aid)
Next, the conductive additive used in the present invention will be described. What is known as a general conductive support agent can be used. For example, graphites such as natural graphite and artificial graphite, carbon blacks such as acetylene black, ketjen black and furnace black, amorphous carbon such as needle coke, vapor-grown carbon fiber and carbon nanotubes, which are electron conductive materials Carbon fibers such as graphene, carbonaceous materials such as graphene and fullerene, metal powders such as copper and nickel, and metal fibers may be used, and conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene, and polyphenylene derivatives may be used. It may be used. Moreover, 1 type may be used among these and 2 or more types may be used.

In the above embodiment, an example in which the solid electrolyte composition according to the present invention contains a positive electrode active material or a negative electrode active material has been shown, but the present invention is not construed as being limited thereto. For example, you may prepare the paste containing a positive electrode active material thru | or a negative electrode active material as a composition which does not contain the said specific binder. At this time, it is preferable to contain said inorganic solid electrolyte. An inorganic solid electrolyte layer may be formed using the solid electrolyte composition according to a preferred embodiment of the present invention in combination with such a commonly used positive electrode material or negative electrode material.
The said negative electrode active material may be used individually by 1 type, or may be used in combination of 2 or more type.

<Current collector (metal foil)>
As the positive / negative current collector, an electron conductor that does not cause a chemical change is preferably used. As the current collector of the positive electrode, those obtained by treating the surface of aluminum or stainless steel with carbon, nickel, titanium or silver in addition to aluminum, stainless steel, nickel, titanium, etc. are preferable. Among them, aluminum, aluminum alloy, The one using stainless steel is more preferable. As the current collector for the negative electrode, aluminum, copper, stainless steel, nickel, titanium, etc., in addition to the surface of aluminum, stainless steel, or copper, carbon, nickel, titanium, or silver is preferably used. A copper alloy or stainless steel is more preferable.

  As the shape of the current collector, a film sheet shape is usually used, but a net, a punched material, a lath body, a porous body, a foamed body, a molded body of a fiber group, and the like can also be used. Although it does not specifically limit as thickness of the said electrical power collector, 1 micrometer-500 micrometers are preferable. Moreover, it is also preferable that the current collector surface is roughened by surface treatment.

<Case>
An electrode sheet having the basic structure of an all-solid-state secondary battery can be produced by arranging the above members. Depending on the application, it may be used as an all-solid secondary battery as it is, but in order to form a dry battery, it is further enclosed in a suitable housing. The housing may be metallic or made of resin (plastic). In the case of using a metallic material, for example, an aluminum alloy or a stainless steel material can be used. The metallic casing is divided into a positive casing and a negative casing, and is electrically connected to the positive collector and the negative collector, respectively. The casing on the positive electrode side and the casing on the negative electrode side are joined and integrated via a gasket for preventing a short circuit.

<Preparation of all-solid secondary battery>
The all-solid-state secondary battery may be manufactured by a conventional method. Specifically, a method of forming an electrode sheet for a battery in which the solid electrolyte composition is applied onto a metal foil serving as a current collector to form a film is exemplified. For example, a composition to be a positive electrode material is applied on a metal foil to form a film. Next, an inorganic solid electrolyte composition is applied to the upper surface of the positive electrode active material layer of the battery electrode sheet to form a film. Furthermore, an electrode sheet having a desired structure of an all-solid-state secondary battery can be obtained by forming a negative electrode active material film and applying a negative electrode current collector (metal foil) in the same manner. If necessary, this can be enclosed in a housing to obtain a desired all-solid secondary battery. In addition, the application | coating method of said each composition should just follow a conventional method. At this time, it is preferable to heat-treat after each application | coating of the composition which comprises a positive electrode active material layer, the composition which comprises an inorganic solid electrolyte layer, and the composition which comprises a negative electrode active material layer. Although heating temperature is not specifically limited, 30 degreeC or more is preferable and 60 degreeC or more is more preferable. The upper limit is preferably 300 ° C. or lower, and more preferably 250 ° C. or lower. By heating in such a temperature range, it is possible to suitably soften the binder while maintaining the particle shape. Thereby, in an all-solid secondary battery, good binding properties and non-pressurized ion conductivity can be obtained.

  Below, the manufacturing method of a solid electrolyte composition is demonstrated in detail by showing an example of an all-solid-state battery preparation process.

(dispersion)
The solid electrolyte composition of the present invention may be mechanically dispersed or pulverized. Examples of the method for pulverizing the inorganic solid electrolyte in the solid electrolyte composition include a mechanical dispersion method. As the mechanical dispersion method, a ball mill, a bead mill, a planetary mixer, a blade mixer, a roll mill, a kneader, a disk mill, or the like is used.

  In the case of dispersion by a ball mill, examples of the material of the ball mill ball include meno, sintered alumina, tungsten carbide, chrome steel, stainless steel, zirconia, plastic polyamide, nylon, silicon nitride, and Teflon (registered trademark). During ball mill dispersion, the same balls may be used, or two or more different balls may be used. Further, in the middle of dispersion, a ball may be added or changed to a ball having a different shape, size, and material. The preferred amount of balls for the container is not particularly specified and may be fully filled. In the dispersion of the solid electrolyte composition, the amount of ball or device-derived contamination generated by impact due to mechanical dispersion is not particularly specified. The amount of contamination can also be suppressed to 10 ppm or less.

In the mechanical dispersion or pulverization treatment, the inorganic solid electrolyte may be dispersed singly or in combination of two or more. The dispersion may be one stage or two or more stages. In addition, a positive electrode or negative electrode active material, an inorganic solid electrolyte, a binder, a dispersant, a dispersion medium, a conductive additive, a lithium salt, or the like can be added between the steps. When the dispersion is performed in multiple stages, the parameters (dispersion time, dispersion speed, dispersion substrate, etc.) of the apparatus relating to dispersion in each stage can be changed.
The dispersion method may be a wet dispersion containing a dispersion medium or a dry dispersion without a dispersion medium, but in the present invention, it is a wet dispersion.

  Generally, the dispersion medium may dissolve a part of the inorganic solid electrolyte during dispersion. In this case, the dissolution part can be regenerated to the original inorganic solid electrolyte by heating at the time of drying. Further, even when the dispersion medium is a water-containing solvent (moisture of 100 ppm or more), the inorganic solid electrolyte can be regenerated by heat drying or vacuum heat drying after dispersion.

  The dispersion time is not particularly specified, but is generally 10 seconds to 10 days. The dispersion temperature is not particularly specified, but is generally in the range of -50 ° C to 100 ° C.

The volume average particle size of the inorganic solid electrolyte dispersed as described above is not particularly limited, but is preferably 0.01 μm or more, more preferably 0.05 μm or more, and further preferably 0.1 μm or more. As an upper limit, 500 micrometers or less are preferable, 100 micrometers or less are more preferable, 50 micrometers is further more preferable, 10 micrometers or less are especially preferable, and 5 micrometers or less are the most preferable. The volume average particle diameter can be measured using a laser diffraction / scattering particle size distribution analyzer LA-920 (trade name, manufactured by HORIBA).
The inorganic solid electrolyte may maintain the original shape before and after the dispersion step, or the shape may be changed.

  When manufacturing a battery electrode sheet, a battery sheet such as a solid electrolyte sheet, and further an all-solid secondary battery using the solid electrolyte dispersion of the present invention, the above-described method for manufacturing the solid electrolyte composition of the present invention The drying in is preferably not performed immediately, but after coating and after forming a coating film. Any drying method such as blow drying, heat drying, or vacuum drying can be used.

  Below, the all-solid-state battery manufacturing process using the solid electrolyte dispersion of this invention is further demonstrated.

(Application)
As the solid electrolyte composition to be applied, the dispersion of the solid electrolyte composition prepared above may be used as it is. However, the dispersion medium used in the above dispersion operation or a solvent different from this may be added or dried once. Then, it may be redispersed with a dispersion medium different from the dispersion medium used in the dispersion operation.
The solid electrolyte composition used for coating may be prepared by mixing two or more types of slurries having different particle dispersity and volume average particle diameter depending on the dispersion process.
In the solid electrolyte composition used for coating, after dispersing only the inorganic solid electrolyte and the dispersion medium, the positive electrode or the negative electrode active material may be added later, or the positive electrode or the negative electrode active material, the inorganic solid electrolyte, and the dispersion medium may be added. You may distribute in a lump. Here, when an additive such as a binder is used, the additive such as a binder may be added before or after the dispersion of the inorganic solid electrolyte.

Application may be either wet application or dry application. Rod bar coating (bar coating method), reverse roll coating, direct roll coating, blade coating, knife coating, extrusion coating, curtain coating, gravure coating, dip coating, squeeze coating, and the like can be used.
The speed of application can be changed according to the viscosity of the inorganic solid electrolyte composition.
It is desirable that the coating film has a uniform film thickness from the beginning to the end of coating. In the case of application using the bar coat method, generally, the first part of the application is thicker and it is thinner as it is finished. Moreover, there exists a tendency which becomes thin according to a peripheral part rather than a center part. In order to prevent these, it is possible to design the clearance between the bar coat and the coating table to be larger at the end of coating than at the beginning of coating. Specifically, a slit is carved on the coating table, and a design in which the slit groove becomes deeper in the later stage than in the initial stage of coating can be considered. Here, a support to be coated is placed on the slit. The application bar remains level with respect to the application table. By doing so, the clearance can be gradually widened. In addition, there is a method in which vibration is applied before the coating film is completely dried to make the coating film thickness variation uniform.
The positive electrode active material layer, the inorganic solid electrolytic layer, and the negative electrode active material layer can be applied stepwise while being dried, or a plurality of different layers can be applied in wet layers. When a different layer is applied, it can be applied with a solvent or dispersion medium different from that of the adjacent layer.

  The inorganic solid electrolyte used in the inorganic solid electrolyte layer may be one kind or two or more kinds in the above-mentioned sulfide-based inorganic solid electrolyte and oxide-based inorganic solid electrolyte, elemental composition and crystal structure. Moreover, you may use the inorganic solid electrolyte which differs in the part which touches an electrode layer (a positive electrode or a negative electrode active material layer), and the inside of an inorganic solid electrolyte layer.

(Dry)
The coating electrode or the dispersion medium is dried for the battery electrode sheet, the solid electrolyte sheet, the two or more layers sheet and the battery sheet obtained by combining them. Any drying method such as blow drying, heat drying, or vacuum drying can be used.

(press)
You may apply | coat, after apply | coating and forming a battery electrode sheet or producing an all-solid-state secondary battery. An example of the pressurizing method is a hydraulic cylinder press. The pressure for pressurization is generally in the range of 50 MPa to 1500 MPa. You may heat simultaneously with pressurization. Generally as heating temperature, it is the range of 30 to 300 degreeC.
It can also be pressed at a temperature higher than the glass transition temperature of the inorganic solid electrolyte. On the other hand, when the inorganic solid electrolyte and the binder coexist, pressing can be performed at a temperature higher than the glass transition temperature of the binder. However, in general, the temperature does not exceed the melting point of the binder.
The pressurization may be performed in a state where the coating solvent or the dispersion medium is previously dried, or may be performed in a state where the solvent or the dispersion medium remains.

The atmosphere during pressurization may be any of air, dry air (dew point -20 ° C. or lower), inert gas (eg, argon, helium, nitrogen).
The press time may be a high pressure for a short time (for example, within several hours), or a medium pressure may be applied for a long time (1 day or more). For example, in the case of an all-solid secondary battery other than the battery electrode sheet or the solid electrolyte sheet, a restraint (screw tightening pressure or the like) of the all-solid-state secondary battery can be used in order to keep applying moderate pressure. .
The pressing pressure may be uniform or different with respect to the coated sheet surface.
The pressing pressure can be changed according to the area and film thickness of the pressed part. Also, the same part can be changed stepwise with different pressures.
The press surface may be smooth or roughened.

(Lamination)
When bonding different layers, it is also preferred that the surfaces that are in contact with each other are wet with an organic solvent, an organic substance, or the like. In the bonding between the electrodes, the solid electrolyte layer may be applied to both layers or one of the layers and bonded before they are dried.
The temperature at the time of bonding may be close to the glass transition temperature of the inorganic solid electrolyte as a temperature higher than that at room temperature.

(Initialize)
The initial charge / discharge is performed with the press pressure increased, and then the pressure is released until the general operating pressure of the all-solid-state secondary battery is reached.

<Uses of all-solid-state secondary batteries>
The all solid state secondary battery according to the present invention can be applied to various uses. Although the application mode is not particularly limited, for example, when installed in an electronic device, a notebook computer, a pen input personal computer, a mobile personal computer, an electronic book player, a cellular phone, a cordless phone, a pager, a handy terminal, a portable fax machine, a portable copy, Examples include portable printers, headphone stereos, video movies, LCD TVs, handy cleaners, portable CDs, minidiscs, electric shavers, transceivers, electronic notebooks, calculators, memory cards, portable tape recorders, radios, backup power supplies, and memory cards. Other consumer products include automobiles, electric vehicles, motors, lighting equipment, toys, game equipment, road conditioners, watches, strobes, cameras, medical equipment (such as pacemakers, hearing aids, and shoulder grinders). Furthermore, it can be used for various military use and space use. Moreover, it can also combine with a solar cell.

  In particular, it is preferably applied to applications that require high capacity and high rate discharge characteristics. For example, in power storage facilities and the like that are expected to increase in capacity in the future, high reliability is indispensable and further compatibility of battery performance is required. In addition, electric vehicles and the like are equipped with high-capacity secondary batteries and are expected to be charged every day at home, and thus more reliability is required for overcharging. According to the present invention, it is possible to exhibit the excellent effect correspondingly to such a usage pattern.

According to a preferred embodiment of the present invention, the following applications are derived.
A solid electrolyte composition (positive electrode or negative electrode composition) containing an active material capable of inserting and releasing metal ions belonging to Group 1 or Group 2 of the Periodic Table.
-The battery electrode sheet which formed the said solid electrolyte composition on metal foil.
A battery electrode sheet comprising a positive electrode active material layer, a negative electrode active material layer, and an inorganic solid electrolyte layer, wherein at least one of the positive electrode active material layer, the negative electrode active material layer, and the inorganic solid electrolyte layer is A battery electrode sheet comprising the inorganic solid electrolyte of the invention and the specific binder described above.
-All-solid-state secondary battery comprised using the said battery electrode sheet.
-An all-solid secondary battery comprising a positive electrode active material layer, a negative electrode active material layer, and an inorganic solid electrolyte layer, wherein at least one of the positive electrode active material layer, the negative electrode active material layer, and the inorganic solid electrolyte layer is All-solid-state secondary battery made into the layer comprised with the solid electrolyte composition.
-The manufacturing method of the electrode sheet for batteries which arrange | positions the said solid electrolyte composition on metal foil, and forms this into a film.
-The manufacturing method of the all-solid-state secondary battery which manufactures an all-solid-state secondary battery via the manufacturing method of the said battery electrode sheet.

An all-solid secondary battery refers to a secondary battery in which the positive electrode, the negative electrode, and the electrolyte are all solid. In other words, it is distinguished from an electrolyte type secondary battery using a carbonate-based solvent as an electrolyte. In this, this invention presupposes an inorganic all-solid-state secondary battery. The all-solid-state secondary battery is classified into a polymer all-solid-state secondary battery using a polymer compound such as polyethylene oxide as an electrolyte and an inorganic all-solid-state secondary battery using the above LLT, LLZ, or the like. The application of the polymer compound to the inorganic all-solid secondary battery is not hindered, and the polymer compound can be applied as a binder for the positive electrode active material, the negative electrode active material, and the inorganic solid electrolyte particles.
The inorganic solid electrolyte is distinguished from an electrolyte (polymer electrolyte) using the above-described polymer compound as an ion conductive medium, and the inorganic compound serves as an ion conductive medium. Specific examples include the above LLT and LLZ. The inorganic solid electrolyte itself does not release cations (Li ions) but exhibits an ion transport function. On the other hand, a material that is added to the electrolytic solution or the solid electrolyte layer and serves as a source of ions that release cations (Li ions) is sometimes called an electrolyte, but it is distinguished from the electrolyte as the ion transport material. This is sometimes referred to as “electrolyte salt” or “supporting electrolyte”. Examples of the electrolyte salt include LiTFSI (lithium bistrifluoromethanesulfonimide).
In the present invention, the term “composition” means a mixture in which two or more components are uniformly mixed. However, as long as the uniformity is substantially maintained, aggregation or uneven distribution may partially occur within a range in which a desired effect is achieved. In particular, the solid electrolyte composition basically refers to a composition (typically a paste) that is a material for forming the electrolyte layer, and the electrolyte layer formed by curing the above composition includes It shall not be included.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not construed as being limited thereto. In the following examples, “parts” and “%” are based on mass unless otherwise specified.

<Example of binder synthesis>
200 parts of ion exchange water, 190 parts of vinylidene fluoride and 10 parts of acrylic acid were added to the autoclave, 2 parts of diisopropyl peroxydicarbonate was added, and the mixture was stirred at 30 ° C. for 24 hours. After completion of the polymerization, the precipitate was filtered and dried at 100 ° C. for 10 hours to obtain polymer (binder) B-1. The obtained binder had a weight average molecular weight of 50,000.

Table 1 summarizes each synthesized binder.
In this example, the molecular weight is rounded off to the nearest 100.

<Table notes>
RU: repeating unit of main chain (a): monomer having specific functional group (a) mass%: ratio of repeating unit (monomer) (corresponding to copolymerization ratio)
For the numbers of P- * and A- *, refer to the above exemplified structures and exemplified compounds.

(Preparation example of solid electrolyte composition)
180 zirconia beads having a diameter of 5 mm are put into a 45 mL container (manufactured by Fritsch) made of zirconia, 9.7 g of inorganic solid electrolyte LLT (manufactured by Toyoshima Seisakusho), 0.3 g of each binder, N-methylpyrrolidone as a dispersion medium After charging 15.0 g, the container was set on a planetary ball mill manufactured by Fritsch, and mixing was continued at 300 rpm for 2 hours to obtain a solid electrolyte composition S-1.

  In Table 2, each obtained solid electrolyte composition is described collectively.

<Table notes>
Numbers in the table are mass ratios (%)
LLT: Li _0.33 La _0.55 TiO ₃
LLZ: Li ₇ La ₃ Zr ₂ O ₁₂
NMP: N-methylpyrrolidone MEK: methyl ethyl ketone DBE: dibutyl ether Li-PS: sulfide-based inorganic solid electrolyte synthesized below BR-A: binder BR-A synthesized below

<Synthesis of sulfide-based inorganic solid electrolyte (Li-PS-based glass)>
In a glove box under an argon atmosphere (dew point -70 ° C.), 2.42 g of lithium sulfide (Li ₂ S, manufactured by Aldrich, purity> 99.98%), diphosphorus pentasulfide (P ₂ S ₅ , manufactured by Aldrich) , Purity> 99%) 3.90 g each was weighed, put into an agate mortar, and mixed for 5 minutes using an agate pestle. Li ₂ S and P ₂ S ₅ had a molar ratio of Li ₂ S: P ₂ S ₅ = 75: 25.
A zirconia 45 mL container (manufactured by Fritsch) was charged with 66 zirconia beads having a diameter of 5 mm, the whole amount of the above mixture was charged, and the container was completely sealed under an argon atmosphere. A container is set on a planetary ball mill P-7 (trade name) manufactured by Frichtu Co., and mechanical milling is performed at 25 ° C. and a rotation speed of 510 rpm for 20 hours. ) 6.20 g was obtained.

(Synthesis of binder BR-A)
To the autoclave, 500 parts of toluene, 99.99 parts of 1,3-butadiene and 0.01 part of dimethylaminoethyl methacrylate were added, 0.3 part of V-601 (trade name, manufactured by Wako Pure Chemical Industries, Ltd.) was added, and 80 parts. The temperature was raised to ° C. and stirred for 3 hours. Thereafter, the temperature was raised to 90 ° C., and the reaction was carried out until the conversion rate reached 100%. The obtained solution was reprecipitated in methanol, and the obtained solid was dried to obtain a target polymer (binder) BR-A.

-Production of solid electrolyte sheet-
The solid electrolyte composition obtained above is applied onto an aluminum foil having a thickness of 20 μm with an applicator having an arbitrary clearance, heated at 80 ° C. for 1 hour and further at 110 ° C. for 1 hour to dry the coating solvent (dispersion medium). It was. Then, it heated and pressurized so that it might become arbitrary density using a heat press machine, and obtained each solid electrolyte sheet of Table 3. The film thickness of the solid electrolyte layer was 30 μm.

Preparation of Secondary Battery Positive Electrode Composition In a planetary mixer (TK Hibismix, manufactured by PRIMIX), 100 parts of the positive electrode active material shown in Table 4, 5 parts of acetylene black, each solid electrolyte composition obtained above 75 Part and N-methylpyrrolidone 270 parts were added and stirred at 40 rpm for 1 hour to prepare a composition for secondary battery positive electrode used in each positive electrode layer shown in Table 4.

Preparation of Secondary Battery Negative Electrode Composition In a planetary mixer (TK Hibismix, manufactured by PRIMIX), 100 parts of the negative electrode active material shown in Table 4, 5 parts of acetylene black, each solid electrolyte composition obtained above 75 Part and N-methylpyrrolidone 270 parts were added and stirred at 40 rpm for 1 hour to prepare a secondary battery negative electrode composition used in each negative electrode layer shown in Table 4.

-Production of positive electrode sheet for secondary battery-
The composition for a secondary battery positive electrode obtained above is applied onto an aluminum foil having a thickness of 20 μm by an applicator having an arbitrary clearance, heated at 80 ° C. for 1 hour and further at 110 ° C. for 1 hour, and applied solvent (dispersion medium) Was dried. Then, it heated and pressurized so that it might become arbitrary density using the heat press machine, and the positive electrode sheet for secondary batteries was obtained.

-Production of electrode sheet for secondary battery-
The solid electrolyte composition obtained above is applied onto the positive electrode sheet for secondary battery obtained above by an applicator having an arbitrary clearance, and heated at 80 ° C. for 1 hour and further at 110 ° C. for 1 hour to obtain a solid electrolyte. A layer was formed. Then, the composition for secondary battery negative electrodes obtained above was further applied on the solid electrolyte layer, and heated at 80 ° C. for 1 hour and further at 110 ° C. for 1 hour to form a negative electrode layer. A copper foil with a thickness of 20 μm was combined on the negative electrode layer, and heated and pressurized to a desired density using a heat press machine, to obtain each secondary battery electrode sheet shown in Table 4.
The electrode sheet for secondary batteries has the structure of FIG. 1, and has a laminated structure of copper foil / negative electrode active material layer / inorganic solid electrolyte layer / secondary battery positive electrode sheet (positive electrode active material layer / aluminum foil). Both the positive electrode layer and the negative electrode layer had a thickness of 80 μm, and the electrolyte layer had a thickness of 30 μm.

<Evaluation of binding properties>
The solid electrolyte layer of the solid electrolyte sheet obtained above or the positive electrode active material layer (length: 50 mm, width: 12 mm) of the positive electrode sheet for a secondary battery is 12 mm wide and 60 mm long. Made) and peeled off by 50 mm at a speed of 10 mm / min. In that case, it evaluated by the area ratio of the sheet | seat part which peeled with respect to the area of the peeled-off cellotape. The measurement was performed 10 times, and an average of 8 measurement values excluding the maximum value and the minimum value was adopted. The average value was adopted using five samples for each test.
The obtained value was evaluated according to the following evaluation criteria.

(Evaluation criteria)
5: 0%
4: More than 0% and less than 5% 3: 5% or more and less than 20% 2: 20% or more and less than 50% 1: 50% or more

<Measurement of ionic conductivity>
The solid electrolyte sheet (Table 3) or secondary battery electrode sheet (Table 4) obtained above is cut into a disk shape with a diameter of 14.5 mm and placed in a stainless steel 2032 type coin case incorporating a spacer and washer. (In the case of using a solid electrolyte sheet, an aluminum foil cut into a disk shape having a diameter of 14.5 mm was further placed in a coin case so as to be in contact with the solid electrolyte layer), and coin cell (measurement of ionic conductivity by non-pressurization) Cell). As shown in FIG. 2, from the outside of the coin battery, it is sandwiched between jigs that can apply pressure between the electrodes, a constraining pressure is applied so that the pressure between the electrodes is 500 kgf / cm ^2, and the ionic conductivity by pressurization. A measurement cell was produced.
In FIG. 2, the coin battery 13 is manufactured, but this is replaced with the ion conductivity measuring cell 13. 11 is an upper support plate, 12 is a lower support plate, 14 is a coin case, 15 is an electrode sheet (solid electrolyte sheet or secondary battery electrode sheet), and S is a screw.

  Using the pressure conductivity measurement cell obtained by pressurization and non-pressurization obtained above, using a 1255B FREQUENCY RESPONSE ANALYZER (trade name) manufactured by SOLARTRON in a constant temperature bath at 30 ° C., a voltage amplitude of 5 mV, a frequency of 1 MHz to AC impedance was measured up to 1 Hz. Thereby, the resistance in the film thickness direction of the sample was obtained, and the ion conductivity was obtained by calculation according to the following formula (1).

Ionic conductivity (mS / cm) =
1000 × sample film thickness (cm) / (resistance (Ω) × sample area (cm ² )) (1)

<High temperature storage stability>
After the coin battery obtained above is allowed to stand in a constant temperature bath at 70 ° C. for one week, the ion conductivity is obtained in the same manner as described above by using the AC impedance method in a constant temperature bath at 30 ° C. The rate of change with respect to the ionic conductivity was determined. The average value was adopted using five samples for each test.
The obtained value was evaluated according to the following evaluation criteria.

(Evaluation criteria)
5: 0% or more and less than 5% 4: 5% or more and less than 15% 3: 15% or more and less than 30% 2: 30% or more and less than 50% 1: 50% or more

<Table notes>
LMO: LiMn ₂ O ₄ lithium manganate LTO: Li ₄ Ti ₅ O ₁₂ lithium titanate LCO: LiCoO ₂ lithium cobaltate NMC: Li (Ni _1/3 Mn _1/3 Co _1/3 ) O ₂ nickel, manganese, Lithium cobalt oxide

  Test No. In 101, it replaces with binder B-1 (functional group A-1) used there as a functional group, A-3, A-5, A-8, A-11, A-14, A-17, A- The battery performance was evaluated in the same manner except that 19, A-20, and A-26 were used. As a result, it was confirmed that excellent performance was exhibited in all of high-temperature storage stability, binding properties, and ionic conductivity when not pressurized.

DESCRIPTION OF SYMBOLS 1 Negative electrode collector 2 Negative electrode active material layer 3 Inorganic solid electrolyte layer 4 Positive electrode active material layer 5 Positive electrode collector 6 Working part 10 All-solid secondary battery 11 Upper support plate 12 Lower support plate 13 Coin battery 14 Coin case 15 Electrode Sheet S Screw

Claims (16)

An all-solid secondary battery comprising a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer, wherein at least one of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer is a periodic table. An all-solid-state secondary battery comprising an inorganic solid electrolyte having conductivity of metal ions belonging to Group 1 or Group 2 and a binder composed of a polymer compound satisfying the following conditions (i) and (ii).
(I) having a repeating unit represented by the following formula (1-1) (ii) having at least one of the following functional group (a)

In the formula, Z ^{11 to} Z ¹⁴ are each independently a hydrogen atom, a chlorine atom, an alkyl group, or a specific fluorine-containing substituent. The specific fluorine-containing substituent is a fluorine atom, a fluoroalkyl group, or a fluoroalkyloxy group. At least one of Z ^{11 to} Z ¹⁴ is a specific fluorine-containing substituent.
Functional group (a)
Carboxyl group, sulfonic acid group, phosphoric acid group, phosphonic acid group, hydroxyl group, thiol group, isocyanate group, oxetane group, epoxy group, dicarboxylic anhydride group, silyl group   The all-solid-state secondary battery of Claim 1 in which the repeating unit represented by the said Formula (1-1) among the said binder is contained 80 mass% or more. The specific fluorine-containing substituent is a fluorine atom, —CF ₃ , —CH ₂ CF ₃ , —CF ₂ CF ₃ , —CF ₂ CF ₂ CF ₃ , —OCF _3, —OCF ₂ CF _3, or —OCF ₂ CF _2. The all-solid-state secondary battery according to claim 1, which is CF ₃ .   The all-solid-state secondary battery according to any one of claims 1 to 3, wherein the binder has a weight average molecular weight of 15,000 to 1,000,000.   The group selected from the functional group (a) is any one of claims 1 to 4 selected from a carboxyl group, a sulfonic acid group, a phosphoric acid group, a phosphonic acid group, a hydroxyl group, a dicarboxylic anhydride group, and a silyl group. 2. The all solid state secondary battery according to item 1.   The all-solid-state secondary battery according to any one of claims 1 to 5, wherein the inorganic solid electrolyte is an oxide-based inorganic solid electrolyte. The all-solid-state secondary battery according to claim 6, wherein the inorganic solid electrolyte is selected from the following formulae.・ Li _xa La _ya TiO ₃
xa = 0.3-0.7, ya = 0.3-0.7
・ Li ₇ La ₃ Zr ₂ O ₁₂
・ Li _3.5 Zn _0.25 GeO ₄
LiTi ₂ P ₃ O ₁₂ ,
_{· Li 1 + xb + yb (} Al, Ga) xb (Ti, Ge) 2-xb Si yb P 3-yb O 12
0 ≦ xb ≦ 1, 0 ≦ yb ≦ 1
・ Li ₃ PO ₄
・ LiPON
・ LiPOD
D is Ti, V, Cr, Mn, Fe, Co, Ni, Cu,
Zr, Nb, Mo, Ru, Ag, Ta, W, Pt, and Au
At least one selected from LiAON
A is at least one selected from Si, B, Ge, Al, C and Ga A solid electrolyte composition applied to an all-solid-state secondary battery, wherein the inorganic solid electrolyte has conductivity of ions of metals belonging to Group 1 or Group 2 of the periodic table, and the following conditions (i) and (ii) A solid electrolyte composition comprising a binder composed of a polymer compound satisfying the above).
(I) having a repeating unit represented by the following formula (1-1) (ii) having at least one of the following functional group (a)

In the formula, Z ^{11 to} Z ¹⁴ are each independently a hydrogen atom, a chlorine atom, an alkyl group, or a specific fluorine-containing substituent. The specific fluorine-containing substituent is a fluorine atom, a fluoroalkyl group, or a fluoroalkyloxy group. At least one of Z ^{11 to} Z ¹⁴ is a specific fluorine-containing substituent.
Functional group (a)
Carboxyl group, sulfonic acid group, phosphoric acid group, phosphonic acid group, hydroxyl group, thiol group, isocyanate group, oxetane group, epoxy group, dicarboxylic anhydride group, silyl group   The solid electrolyte composition according to claim 8, comprising a dispersion medium.   The solid electrolyte composition according to claim 9, wherein the dispersion medium is selected from an alcohol compound solvent, an ether compound solvent, an amide compound solvent, a ketone compound solvent, an aromatic compound solvent, an aliphatic compound solvent, and a nitrile compound solvent.   The solid electrolyte composition according to any one of claims 8 to 10, wherein the binder is contained in an amount of 0.1 to 20 parts by mass with respect to 100 parts by mass of the inorganic solid electrolyte.   The solid electrolyte composition according to any one of claims 8 to 11, comprising a positive electrode active material.   The solid electrolyte composition according to any one of claims 8 to 12, wherein the inorganic solid electrolyte is an oxide-based inorganic solid electrolyte. A battery electrode sheet comprising a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer, wherein at least one of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer is a periodic table first. An electrode sheet for a battery, comprising an inorganic solid electrolyte having conductivity of ions of metals belonging to Group 2 or Group 2 and a binder composed of a polymer compound satisfying the following conditions (i) and (ii).
(I) having a repeating unit represented by the following formula (1-1) (ii) having at least one of the following functional group (a)

In the formula, Z ^{11 to} Z ¹⁴ are each independently a hydrogen atom, a chlorine atom, an alkyl group, or a specific fluorine-containing substituent. The specific fluorine-containing substituent is a fluorine atom, a fluoroalkyl group, or a fluoroalkyloxy group. At least one of Z ^{11 to} Z ¹⁴ is a specific fluorine-containing substituent.
Functional group (a)
Carboxyl group, sulfonic acid group, phosphoric acid group, phosphonic acid group, hydroxyl group, thiol group, isocyanate group, oxetane group, epoxy group, dicarboxylic anhydride group, silyl group   The manufacturing method of the battery electrode sheet which forms the solid electrolyte composition of any one of Claims 8-13 on metal foil.   The manufacturing method of the all-solid-state secondary battery which manufactures an all-solid-state secondary battery via the manufacturing method of the electrode sheet for batteries of Claim 15.

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