WO2017199821A1

WO2017199821A1 - Solid electrolyte composition, solid electrolyte-containing sheet, all-solid-state secondary battery, method for producing solid electrolyte-containing sheet, and method for producing all-solid-state secondary battery

Info

Publication number: WO2017199821A1
Application number: PCT/JP2017/017757
Authority: WO
Inventors: 雅臣牧野; 宏顕望月; 智則三村
Original assignee: 富士フイルム株式会社
Priority date: 2016-05-19
Filing date: 2017-05-10
Publication date: 2017-11-23
Also published as: JPWO2017199821A1; JP6684901B2

Abstract

A solid electrolyte composition which contains an inorganic solid electrolyte having conductivity for ions of metals in group 1 or group 2 of the periodic table, a dehydrating agent and a dispersion medium; a solid electrolyte-containing sheet which contains an inorganic solid electrolyte having conductivity for ions of metals in group 1 or group 2 of the periodic table and a dehydrating agent; an all-solid-state secondary battery; a method for producing a solid electrolyte-containing sheet; and a method for producing an all-solid-state secondary battery.

Description

SOLID ELECTROLYTE COMPOSITION, SOLID ELECTROLYTE-CONTAINING SHEET AND ALL-SOLID SECONDARY BATTERY

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

A lithium ion secondary battery is a storage battery that has a negative electrode, a positive electrode, and an electrolyte sandwiched between the negative electrode and the positive electrode, and enables charging and discharging by reciprocating lithium ions between the two electrodes. Conventionally, an organic electrolytic solution has been used as an electrolyte in a lithium ion secondary battery. However, the organic electrolyte is liable to leak, and there is a possibility that a short circuit occurs inside the battery due to overcharge or overdischarge, resulting in ignition, and further improvements in reliability and safety are required.
Under such circumstances, an all-solid secondary battery using an inorganic solid electrolyte instead of an organic electrolyte has been attracting attention. All-solid-state secondary batteries are composed of a solid negative electrode, electrolyte, and positive electrode, which can greatly improve safety and reliability, which is a problem of batteries using organic electrolytes, and can also extend the life. It will be. Furthermore, the all-solid-state secondary battery can have a structure in which electrodes and an electrolyte are directly arranged in series. Therefore, it is possible to increase the energy density as compared with a secondary battery using an organic electrolyte, and application to an electric vehicle, a large storage battery, and the like is expected.

Because of the above advantages, all-solid-state secondary batteries are being developed as next-generation lithium-ion batteries. For example, Patent Document 1 describes an all-solid-state secondary battery that can prevent generation of hydrogen sulfide due to reaction with moisture in the atmosphere while ensuring conductivity using a sulfide-based inorganic solid electrolyte. ing. In this all solid state secondary battery, the sulfide-based inorganic solid electrolyte is coated with a liquid substance.

JP 2009-117168 A

The all-solid-state secondary battery described in Patent Document 1 can prevent functional deterioration of the sulfide-based inorganic solid electrolyte depending on the production method, and can improve the performance of the all-solid-state secondary battery such as battery voltage to some extent. it can. However, when an all-solid secondary battery is manufactured using a solid electrolyte composition comprising a sulfide-based inorganic solid electrolyte coated with a liquid material and a dispersion medium, the dispersion medium and the liquid material are compatible. The sulfide-based inorganic solid electrolyte coating may be removed. As a result, the sulfide-based inorganic solid electrolyte comes into contact with moisture in the dispersion medium, and the function as the electrolyte and the performance of the all-solid secondary battery are reduced.

In view of the above problems, an object of the present invention is to provide a solid electrolyte composition in which the reaction between an inorganic solid electrolyte and moisture is suppressed and an excellent battery voltage can be realized in an all-solid secondary battery. In addition, the present invention provides a solid electrolyte-containing sheet capable of realizing an excellent battery voltage in an all-solid secondary battery in which the reaction between the inorganic solid electrolyte and moisture is suppressed, and an all-solid secondary battery using the solid electrolyte-containing sheet. The issue is to provide. Furthermore, this invention makes it a subject to provide the manufacturing method of the said solid electrolyte containing sheet and an all-solid-state secondary battery.

As a result of intensive studies by the present inventors, it has been found that a solid electrolyte composition containing a dehydrating agent, a specific inorganic solid electrolyte, and a dispersion medium is excellent in stability over time, and the solid electrolyte composition is used. Thus, it has been found that an all-solid secondary battery excellent in battery voltage can be realized. The present invention has been further studied based on these findings and has been completed.

That is, the above problem has been solved by the following means.
<1> Solid electrolyte composition containing an inorganic solid electrolyte (A) having conductivity of ions of metals belonging to Group 1 or Group 2 of the periodic table, a dehydrating agent (B), and a dispersion medium (C) object.
<2> The solid electrolyte composition according to <1>, wherein the inorganic solid electrolyte (A) is a sulfide-based inorganic solid electrolyte.
<3> The solid electrolyte composition according to <1> or <2>, wherein the dehydrating agent (B) is an organic compound having a partial structure in which two or more oxygen atoms are bonded to the same carbon atom or the same sulfur atom.

<4> The dehydrating agent (B) is an organic compound that reacts with water to form a product having a partial structure represented by any one of the following general formulas (1) to (3) <1> to <3> The solid electrolyte composition according to any one of 3>.

In the general formulas (1) to (3), R ¹ , R ² , R ³¹ and R ³² each independently represent a hydrogen atom, an alkyl group or an aryl group. X ¹ , X ² , X ³¹ and X ³² each independently represent a single bond, an oxygen atom, a sulfur atom or —N (R ³ ) —. R ³ represents a hydrogen atom, an alkyl group or an aryl group. Y ¹ represents a carbon atom or a sulfur atom. Y ² represents a sulfur atom. Y ³ represents a phosphorus atom. * Indicates a linking site in the product.

<5> The solid according to any one of <1> to <4>, wherein the dehydrating agent (B) is at least one selected from the group consisting of acid anhydrides, acid halides, acetals, and orthoesters. Electrolyte composition.
<6> The solid electrolyte composition according to any one of <1> to <5>, wherein the dehydrating agent (B) is an organic compound having a fluorine atom.
<7> The solid according to any one of <1> to <6>, wherein the content of the dehydrating agent (B) is 1% by mass or more and 50% by mass or less in the total solid content of the solid electrolyte composition. Electrolyte composition.
<8> The solid electrolyte composition according to any one of <1> to <7>, wherein the dehydrating agent (B) has a molecular weight of 300 or less or a boiling point at 760 mmHg of 300 ° C. or less.
<9> The dehydrating agent (B) is liquid at 25 ° C., and the mass ratio (B) / (C) to the dispersion medium (C) is 1/99 to 99/1. The solid electrolyte composition as described in any one.
<10> The solid electrolyte composition according to any one of <1> to <9>, which contains an active material (D).
<11> The solid electrolyte composition according to any one of <1> to <10>, containing a binder (E).
<12> The solid according to <11>, wherein the binder (E) is at least one selected from the group consisting of an acrylic resin, a polyurethane resin, a polyurea resin, a polyimide resin, a fluorine-containing resin, and a hydrocarbon-based thermoplastic resin. Electrolyte composition.
<13> The solid electrolyte composition according to <11> or <12>, wherein the binder (E) has a polar group.

<14> A solid electrolyte-containing sheet containing an inorganic solid electrolyte (A) having conductivity of ions of metals belonging to Group 1 or Group 2 of the periodic table and a dehydrating agent (B).
<15> The method for producing a solid electrolyte-containing sheet according to <14>, wherein the dehydrating agent (B) is contained in a total solid content of 5% by mass or less.
Filtering the solid electrolyte composition containing the inorganic solid electrolyte (A), the dehydrating agent (B), and the dispersion medium (C);
Applying the filtrate obtained in the above step onto a substrate;
The manufacturing method of the solid electrolyte containing sheet | seat which has the process of heat-drying.
<16> An all-solid secondary battery comprising a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer,
An all-solid-state secondary battery, wherein at least one of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer is the solid electrolyte-containing sheet according to <14>.
<17> A method for producing an all-solid secondary battery, wherein an all-solid secondary battery is produced through the production method according to <15>.

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.
In the present specification, when “acryl” or “(meth) acryl” is simply described, it means methacryl and / or acryl. The term “acryloyl” or “(meth) acryloyl” simply means methacryloyl and / or acryloyl.

In the present specification, unless otherwise specified, the mass average molecular weight (Mw) can be measured as a molecular weight in terms of polystyrene by GPC. At this time, GPC device HLC-8220 (manufactured by Tosoh Corporation) is used, G3000HXL + G2000HXL is used as the column, the flow rate is 1 mL / min at 23 ° C., and detection is performed by RI. The eluent can be selected from THF (tetrahydrofuran), chloroform, NMP (N-methyl-2-pyrrolidone), m-cresol / chloroform (manufactured by Shonan Wako Pure Chemical Industries, Ltd.) and dissolves. If present, use THF.

In the solid electrolyte composition of the present invention, the reaction between the inorganic solid electrolyte and moisture is suppressed, and an excellent battery voltage can be realized in an all-solid secondary battery produced using this solid electrolyte composition. In the solid electrolyte-containing sheet of the present invention, the reaction between the inorganic solid electrolyte and moisture is suppressed, and an excellent battery voltage can be realized in an all-solid secondary battery. Moreover, the all-solid-state secondary battery of this invention is excellent in a battery voltage.
Moreover, according to the manufacturing method of this invention, the solid electrolyte containing sheet | seat and all-solid-state secondary battery of this invention can be manufactured.
The above and other features and advantages of the present invention will become more apparent from the following description, with reference where appropriate to the accompanying drawings.

FIG. 1 is a longitudinal sectional view schematically showing an all solid state secondary battery according to a preferred embodiment of the present invention. FIG. 2 is a longitudinal sectional view schematically showing the test apparatus used in the examples. FIG. 3 is a longitudinal sectional view schematically showing an all solid state secondary battery (coin battery) produced in the example.

<Preferred embodiment>
FIG. 1 is a cross-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 this embodiment has a negative electrode current collector 1, a negative electrode active material layer 2, a solid electrolyte layer 3, a positive electrode active material layer 4, and a positive electrode current collector 5 in this order as viewed from the negative electrode side. . 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. The solid electrolyte composition of the present invention can be preferably used as a molding material for the negative electrode active material layer, the positive electrode active material layer, and the solid electrolyte layer. The solid electrolyte-containing sheet of the present invention is suitable as the negative electrode active material layer, the positive electrode active material layer, and the solid electrolyte layer.
In this specification, a positive electrode active material layer (hereinafter also referred to as a positive electrode layer) and a negative electrode active material layer (hereinafter also referred to as a negative electrode layer) may be collectively referred to as an electrode layer or an active material layer.
In addition, when putting the all-solid-state secondary battery having the layer configuration shown in FIG. 1 into a 2032 type coin case, the all-solid-state secondary battery having the layer configuration shown in FIG. A battery produced by placing an electrode sheet for an all-solid secondary battery in a 2032 type coin case may be referred to as an all-solid secondary battery.

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, the thickness is preferably 10 to 1,000 μm, more preferably 20 μm or more and less than 500 μm. 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.

<Solid electrolyte composition>
The solid electrolyte composition of the present invention includes an inorganic solid electrolyte (A) having conductivity of ions of metals belonging to Group 1 or Group 2 of the periodic table, a dehydrating agent (B), and a dispersion medium (C). Containing.
Hereinafter, the inorganic solid electrolyte (A), the dehydrating agent (B), and the dispersion medium (C) may be referred to as an inorganic solid electrolyte, a dehydrating agent, and a dispersion medium, respectively.

(Inorganic solid electrolyte (A))
The inorganic solid electrolyte is an inorganic solid electrolyte, and the solid electrolyte is a solid electrolyte capable of moving ions inside. Since it does not contain organic substances as the main ion conductive material, organic solid electrolytes (polymer electrolytes typified by polyethylene oxide (PEO), etc., organics typified by lithium bis (trifluoromethanesulfonyl) imide (LiTFSI), etc. It is clearly distinguished from the electrolyte salt). In addition, since the inorganic solid electrolyte is solid in a steady state, it is not usually dissociated or released into cations and anions. In this respect, it is also clearly distinguished from inorganic electrolyte salts (such as LiPF ₆ , LiBF ₄ , LiFSI, LiCl, etc.) in which cations and anions are dissociated or liberated in the electrolyte 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. In the present invention, since a better interface can be formed between the active material and the inorganic solid electrolyte, a sulfide-based inorganic solid electrolyte is preferably used.

(I) Sulfide-based inorganic solid electrolyte The sulfide-based inorganic solid electrolyte contains a sulfur atom (S) and has ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and Those having electronic insulating properties are preferred. 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 formula (I) is exemplified.

L _a1 M _b1 P _c1 S _d1 A _e1 Formula (I)

In the formula, L represents an element selected from Li, Na and K, and Li is preferred. M represents an element selected from B, Zn, Sn, Si, Cu, Ga, Sb, Al, and Ge. A represents an element selected from I, Br, Cl and F. a1 to e1 indicate the composition ratio of each element, and a1: b1: c1: d1: e1 satisfies 1 to 12: 0 to 5: 1: 2 to 12: 0 to 10. a1 is further preferably 1 to 9, and more preferably 1.5 to 7.5. b1 is preferably 0 to 3. Further, d1 is preferably 2.5 to 10, and more preferably 3.0 to 8.5. Further, e1 is preferably 0 to 5, and more preferably 0 to 3.

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 as described below.

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 system glass containing Li, P and S, or Li—PS system glass ceramics containing Li, P and S can be used.
The sulfide-based inorganic solid electrolyte includes, for example, lithium sulfide (Li ₂ S), phosphorus sulfide (for example, diphosphorus pentasulfide (P ₂ S ₅ )), simple phosphorus, simple sulfur, sodium sulfide, hydrogen sulfide, lithium halide (for example, LiI, LiBr, LiCl) and a sulfide of an element represented by M (for example, SiS ₂ , SnS, GeS ₂ ) can be produced by reaction of at least two raw materials.

The ratio of Li ₂ S to P ₂ S ₅ in the Li—PS system glass and Li—PS system glass ceramic is a molar ratio of Li ₂ S: P ₂ S ₅ , preferably 60:40 to 90:10, more preferably 68:32 to 78:22. 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 particular upper limit, it is practical that it is 1 × 10 ⁻¹ S / cm or less.

Examples of combinations of raw materials are shown below as specific examples of sulfide-based inorganic solid electrolytes. For example, Li ₂ S—P ₂ S ₅ , Li ₂ S—P ₂ S ₅ —LiCl, Li ₂ S—P ₂ S ₅ —H ₂ S, Li ₂ S—P ₂ S ₅ —H ₂ S—LiCl, 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 —SiS ₂ —LiCl, 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. However, the mixing ratio of each raw material does not matter. Examples of a method for synthesizing a sulfide-based inorganic solid electrolyte material using such a raw material composition include an amorphization method. Examples of the amorphization method include a mechanical milling method, a solution method, and a melt quench method. This is because processing at room temperature is possible, and the manufacturing process can be simplified.

(Ii) Oxide-based inorganic solid electrolyte The oxide-based inorganic solid electrolyte contains an oxygen atom (O) and has ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and A compound having an electronic insulating property is preferable.

Specific examples of the compound include Li _xa La _ya TiO ₃ [xa = 0.3 to 0.7, ya = 0.3 to 0.7] (LLT), Li _xb La _yb Zr _zb M ^bb _mb O _nb ( ^Mbb is at least one element selected from Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In, and Sn, xb satisfies 5 ≦ xb ≦ 10, and yb satisfies 1 ≦ yb. ≦ 4, zb satisfies 1 ≦ zb ≦ 4, mb satisfies 0 ≦ mb ≦ 2, nb satisfies 5 ≦ nb ≦ 20), Li _xc B _yc M ^cc _zc _Onc (M ^cc is C, S, Al, Si, Ga, Ge, In, Sn are at least one element, xc satisfies 0 ≦ xc ≦ 5, yc satisfies 0 ≦ yc ≦ 1, and zc satisfies 0 ≦ zc ≦ met 1, nc satisfies 0 ≦ nc ≦ 6.), Li xd ( _{_{l, Ga) yd (Ti,}} Ge) zd Si ad P md O nd ( provided that, 1 ≦ xd ≦ 3,0 ≦ yd ≦ 1,0 ≦ zd ≦ 2,0 ≦ ad ≦ 1,1 ≦ md ≦ 7, 3 ≦ nd ≦ 13), Li _(3-2xe) M ^ee _xe D ^ee O (xe represents a number from 0 to 0.1, and M ^ee represents a divalent metal atom. D ^ee represents a halogen atom or Represents a combination of two or more halogen atoms.), Li _xf Si _yf O _zf (1 ≦ xf ≦ 5, 0 <yf ≦ 3, 1 ≦ zf ≦ 10), Li _xg S _yg O _zg (1 ≦ xg ≦ 3, 0 <yg ≦ 2, 1 ≦ zg ≦ 10), Li ₃ BO ₃ —Li ₂ SO ₄ , Li ₂ O—B ₂ O ₃ —P ₂ O ₅ , Li ₂ O—SiO ₂ , Li ₆ BaLa ₂ _{_{_{_{ta 2 O 12, Li 3 PO}}}} (4-3 / 2w) N w (w is w <1), LI ICON (Lithium super ionic conductor) type _Li 3.5 _Zn 0.25 GeO ₄ having a crystal structure, _La 0.55 _Li 0.35 _TiO 3 having a perovskite crystal structure, NASICON (Natrium super ionic conductor) type crystal structure LiTi ₂ P ₃ O ₁₂ , Li _{1 + xh + yh} (Al, Ga) _xh (Ti, Ge) _2-xh Si _yh P _3-yh O ₁₂ (where 0 ≦ xh ≦ 1, 0 ≦ yh ≦ 1), garnet Examples include Li ₇ La ₃ Zr ₂ O ₁₂ (LLZ) having a type crystal structure. Phosphorus compounds containing Li, P and O are also desirable. For example, lithium phosphate (Li ₃ PO ₄ ), LiPON obtained by replacing a part of oxygen of lithium phosphate with nitrogen, LiPOD ¹ (D ¹ is Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr) , Nb, Mo, Ru, Ag, Ta, W, Pt, Au, etc.). LiA ¹ ON (A ¹ is at least one selected from Si, B, Ge, Al, C, Ga, etc.) and the like can also be preferably used.

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 average particle diameter of an inorganic solid electrolyte particle is performed in the following procedures. The inorganic solid electrolyte particles are diluted and adjusted in a 20 ml sample bottle using water (heptane in the case of a substance unstable to water). The diluted dispersion sample is irradiated with 1 kHz ultrasonic waves for 10 minutes and used immediately after that. Using this dispersion liquid sample, using a laser diffraction / scattering particle size distribution analyzer LA-920 (manufactured by HORIBA), data acquisition was performed 50 times using a measurement quartz cell at a temperature of 25 ° C. Get the diameter. For other detailed conditions, the description of JISZ8828: 2013 “Particle Size Analysis—Dynamic Light Scattering Method” is referred to as necessary. Five samples are prepared for each level, and the average value is adopted.

The content of the solid component in the solid electrolyte composition of the inorganic solid electrolyte is 100% by mass of the solid component when considering the reduction of the interface resistance when used in an all-solid secondary battery and the maintenance of the reduced interface resistance. It is preferably 5% by mass or more, more preferably 10% by mass or more, and particularly preferably 20% by mass or more. 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.
The said inorganic solid electrolyte may be used individually by 1 type, or may be used in combination of 2 or more type.
In the present specification, solid content (solid component) refers to a component that does not disappear by evaporation or evaporation when subjected to a drying treatment at 170 ° C. for 6 hours in a nitrogen atmosphere. Typically, it refers to components other than the dispersion medium described below.

(Dehydrating agent (B))
The solid electrolyte composition of the present invention contains a dehydrating agent in order to suppress alteration of the inorganic solid electrolyte due to reaction with water. The dehydrating agent used in the present invention means a compound that adsorbs water or reacts with water, and includes a desiccant and a water absorbing agent. In the present invention, the dehydrating agent is not particularly limited and may be either an organic compound or an inorganic compound.
In the present invention, the dehydrating agent may be used alone or in combination of two or more.

Among the dehydrating agents, specific examples of inorganic compounds include diphosphorus pentoxide, phosphorus trichloride, molecular sieves (3A, 4A, 5A, 13X), silica gel, zeolite, lithium chloride, calcium chloride, sodium sulfate, magnesium sulfate, Examples include aluminum oxide, calcium oxide, metal Na, metal Li, and metal hydride. Specific examples of metal hydrides include lithium hydride, lithium borohydride, sodium hydride, calcium hydride, sodium borohydride, and lithium aluminum hydride.
Among these, molecular sieves adsorb water, and others exhibit a dehydrating function by reacting with water. Hereinafter, the inorganic compound dehydrating agent may be referred to as an inorganic dehydrating agent.
What is necessary is just to use the said inorganic type dehydrating agent in the aspect normally used as a dehydrating agent. For example, molecular sieves that are sufficiently dried are used.

As the inorganic dehydrating agent, a chemical desiccant that uses the intrinsic properties of chemical substances (chemical reaction, deliquescence) and a physical desiccant that uses the property that water molecules are easily adsorbed on the porous surface should be used. it can.

Among the dehydrating agents, organic compounds exhibit a dehydrating function by reacting with water. Hereinafter, the organic compound dehydrating agent may be referred to as an organic dehydrating agent.

As the organic dehydrating agent, an organic compound having a heteroatom-containing double bond is preferable because it has an electrophilic property capable of reacting with water.
Specific examples of the hetero atom include an oxygen atom, a sulfur atom, a phosphorus atom and a nitrogen atom. Specific examples of the heteroatom-containing double bond include C═O, S═O, P═O and C═N.

In addition, as an organic dehydrating agent, an organic compound having a partial structure in which two or more oxygen atoms are bonded to the same carbon atom or the same sulfur atom in order to rapidly react with water and consume water by being highly reactive with water Is preferred.
Specific examples of the partial structure in which two or more oxygen atoms are bonded to the same carbon atom include> C (—O—) ₂ and —C (═O) O—. On the other hand, a specific example of a partial structure in which two or more sulfur atoms are bonded to the same carbon atom includes> S (= O) ₂ .

Further, as an organic dehydrating agent, when the hydrolysis by-product is an acidic compound, it is difficult to lower the ionic conductivity with respect to the inorganic solid electrolyte, so that it reacts with water and the following general formulas (1) to (3) The organic compound which forms the product which has the partial structure represented by either of these is preferable.

As the alkyl group for R ¹ to R ³ , R ³¹ and R ³² , an alkyl group for the substituent P described later is preferable. Preferred are alkyl groups having 1 to 12 carbon atoms, more preferred are 1 to 6 carbon atoms, and particularly preferred are methyl and ethyl.
As the aryl group of R ¹ to R ³ , R ³¹ and R ^32, an aryl group in the substituent P described later is preferable.

Specific examples of the organic compound forming the product having the partial structure represented by the general formula (1) include formic acid, acetic acid, propionic acid, pivalic acid, trifluoroacetic acid, acrylic acid, methacrylic acid, and esters thereof. Can be mentioned.
Specific examples of the organic compound forming the product having the partial structure represented by the general formula (2) include methanesulfonic acid, ethanesulfonic acid, trifluoromethanesulfonic acid, vinylsulfonic acid, and esters thereof.
Specific examples of the organic compound forming the product having the partial structure represented by the general formula (3) include methylphosphonic acid, ethylphosphonic acid, vinylphosphonic acid, phenylphosphonic acid and esters thereof.
The present invention is not limited to the above specific examples.

As organic dehydrating agents, acid anhydrides, acid halides, acetals, and orthoesters are preferably used because they are highly reactive with water and rapidly hydrolyze to consume water. Acetal is a compound having a structure> C (OR) ₂ (R represents an arbitrary organic group), and includes both a compound obtained from an aldehyde and a compound (ketal) obtained from a ketone.

The dehydrating agent used in the present invention is preferably an organic compound having a fluorine atom, and more preferably a perfluoro organic compound. This is because by having a fluorine atom, in addition to the original dehydrating effect of the dehydrating agent, it has the effect of suppressing the entry of water into the composition due to the presence of the dehydrating agent.
Specific examples of the organic dehydrating agent include alkyl lithium (for example, normal butyl lithium, sec-butyl lithium, tert-butyl lithium, methyl lithium and phenyl lithium), metal amide (for example, lithium diisopropylamide, lithium-2,2, 6,6-tetramethylpiperidide, lithium hexamethyldisilazide, lithium amide and sodium amide), silane coupling agents, carboxylic anhydrides (eg acetic anhydride, trifluoroacetic anhydride, succinic anhydride), sulfones Acid anhydride (for example, trifluoromethanesulfonic anhydride), carboxylic acid halide (carboxylic acid chloride is preferable, for example, acetic acid chloride), sulfonic acid halide (sulfonic acid chloride is preferable, for example, trifluoromethanesulfonic acid chloride) De) Orutoiso acid trimethyl and the following exemplified compound (B-1) include ~ (B-4).

The content of the dehydrating agent in the solid electrolyte composition is not particularly limited, but in order to exert a sufficient drying capacity while excluding adverse effects on the inorganic solid electrolyte, the total solid content is 1% by mass or more and 50% by mass or less. It is preferably 2% by mass or more and 30% by mass or less, more preferably 3% by mass or more and 20% by mass or less.

The dehydrating agent may be dissolved in the solid electrolyte composition or insoluble. When insoluble, it may exist evenly in the solid electrolyte composition or may be unevenly distributed. In the case of uneven distribution, the dehydrating agent may be present at the upper interface or the lower interface in the solid electrolyte composition. In particular, it is preferable that a dehydrating agent exists between the solid electrolyte composition and an interface with which moisture can come into contact.

The molecular weight and boiling point of the dehydrating agent used in the present invention are not particularly limited, but the boiling point at a molecular weight of 300 or less or 760 mmHg may be 300 ° C. or less in order to efficiently remove excess dehydrating agent when preparing the solid electrolyte-containing sheet. preferable.
It is practical that the lower limit of the molecular weight is 50 or more. On the other hand, the lower limit of the boiling point at 760 mmHg is practically 25 ° C. or higher.

The dehydrating agent (B) used in the present invention is a liquid at 25 ° C. and exhibits a mass ratio (B) / weight to the dispersion medium (C) in order to exhibit a sufficient drying ability while excluding adverse effects on the inorganic solid electrolyte. (C) is preferably 1/99 to 99/1, more preferably 5/95 to 50/5, and particularly preferably 10/90 to 30/70.

In the present specification, a compound, partial structure or group for which substitution or non-substitution is not clearly specified means that the compound, partial structure or group may have an appropriate substituent. This is also synonymous for compounds that do not specify substituted or unsubstituted. Preferable substituents include the following substituent P.
Examples of the substituent P 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 and the like), an alkynyl group (preferably an alkynyl group having 2 to 20 carbon atoms such as ethynyl, butadiynyl, phenylethynyl and the like), A cycloalkyl group (preferably a cycloalkyl group having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc., but in this specification, an alkyl group usually means a cycloalkyl group) ), An aryl group (preferably Aryl groups having 6 to 26 elemental atoms such as phenyl, 1-naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methylphenyl and the like, aralkyl groups (preferably aralkyl groups having 7 to 23 carbon atoms such as Benzyl, phenethyl and the like), a heterocyclic group (preferably a heterocyclic group having 2 to 20 carbon atoms, preferably 5 or 6 having at least one selected from an oxygen atom, a sulfur atom and a nitrogen atom as a ring-constituting atom Preferred are membered heterocyclic groups such as tetrahydropyranyl, tetrahydrofuranyl, 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzoimidazolyl, 2-thiazolyl, 2-oxazolyl, pyrrolidone group, etc.), alkoxy groups ( Preferably an alkoxy group having 1 to 20 carbon atoms such as methoxy, ethoxy, Propyloxy, benzyloxy, etc.), aryloxy groups (preferably aryloxy groups having 6 to 26 carbon atoms, such as phenoxy, 1-naphthyloxy, 3-methylphenoxy, 4-methoxyphenoxy, etc., but in this specification, An alkoxy group usually means an aryloyl group), an alkoxycarbonyl group (preferably an alkoxycarbonyl group having 2 to 20 carbon atoms, such as ethoxycarbonyl, 2-ethylhexyloxycarbonyl, etc.), an aryloxycarbonyl group ( Preferably, the aryloxycarbonyl group having 6 to 26 carbon atoms such as phenoxycarbonyl, 1-naphthyloxycarbonyl, 3-methylphenoxycarbonyl, 4-methoxyphenoxycarbonyl, etc.), amino group (preferably carbon atom) Including an amino group having 0 to 20 atoms, an alkylamino group, and 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 and the like, an acyl group (preferably an acyl group having 1 to 20 carbon atoms such as acetyl and propionyl). , Butyryl, etc.), an aryloyl group (preferably an aryloyl group having 7 to 23 carbon atoms, such as benzoyl, etc., but an acyl group in this specification usually means an aryloyl group). ), An acyloxy group (preferably an acyloxy group having 1 to 20 carbon atoms, such as acetyloxy), an aryloyloxy group (preferably an aryloyloxy group having 7 to 23 carbon atoms, such as benzoyloxy, etc., provided that In this specification, an acyloxy group usually means an aryloyloxy group), a carbamoyl group (preferably a carbamoyl group having 1 to 20 carbon atoms, such as N, N-dimethylcarbamoyl, N-phenylcarbamoyl, etc. ), An acylamino group (preferably an acylamino group having 1 to 20 carbon atoms, such as acetylamino, benzoylamino, etc.), an alkylsulfanyl group (preferably an alkylsulfanyl group having 1 to 20 carbon atoms, such as methylsulfanyl, ethyl Sulfanyl, isopropyl Sulfanyl, benzylsulfanyl, etc.), arylsulfanyl groups (preferably arylsulfanyl groups having 6 to 26 carbon atoms, such as phenylsulfanyl, 1-naphthylsulfanyl, 3-methylphenylsulfanyl, 4-methoxyphenylsulfanyl, etc.), alkylsulfonyl A group (preferably an alkylsulfonyl group having 1 to 20 carbon atoms, such as methylsulfonyl or ethylsulfonyl), an arylsulfonyl group (preferably an arylsulfonyl group having 6 to 22 carbon atoms, such as benzenesulfonyl), an alkyl, etc. A silyl group (preferably an alkylsilyl group having 1 to 20 carbon atoms, such as monomethylsilyl, dimethylsilyl, trimethylsilyl, triethylsilyl, etc.), an arylsilyl group (preferably 6 to 4 carbon atoms) Arylsilyl groups such as triphenylsilyl), alkoxysilyl groups (preferably alkoxysilyl groups having 1 to 20 carbon atoms such as monomethoxysilyl, dimethoxysilyl, trimethoxysilyl, triethoxysilyl, etc.), aryl An oxysilyl group (preferably an aryloxysilyl group having 6 to 42 carbon atoms, such as triphenyloxysilyl), a phosphoryl group (preferably a phosphoryl group having 0 to 20 carbon atoms, such as —OP (═O) (R ^P ) ₂ ), a phosphonyl group (preferably a phosphonyl group having 0 to 20 carbon atoms, such as —P (═O) (R ^P ) ₂ ), a phosphinyl group (preferably phosphinyl having 0 to 20 carbon atoms). Groups such as -P (R ^P ) ₂ ), (meth) acryloyl groups, (meth) acryloyloxy groups, ( (Meth) acryloylumimino group ((meth) acrylamide group), hydroxy group, sulfanyl group, carboxy group, phosphoric acid group, phosphonic acid group, sulfonic acid group, cyano group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, Iodine atom).
In addition, each of the groups listed as the substituent P may be further substituted with the substituent P described above.
When the compound, substituent, linking group and the like include an alkyl group, an alkylene group, an alkenyl group, an alkenylene group, an alkynyl group and / or an alkynylene group, these may be cyclic or linear, and may be linear or branched. It may be substituted as described above or unsubstituted.

(Dispersion medium (C))
The solid electrolyte composition of the present invention contains a dispersion medium for dispersing solid components. Specific examples of the dispersion medium include the following.

Examples of the alcohol compound solvent include methyl alcohol, ethyl alcohol, 1-propyl alcohol, 2-butanol, ethylene glycol, propylene glycol, glycerin, 1,6-hexanediol, 1,3-butanediol, and 1,4-butane. Diols are mentioned.

Examples of ether compound solvents include alkylene glycol alkyl ethers (ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol, dipropylene glycol, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, polyethylene glycol, propylene glycol dimethyl ether, dipropylene glycol monomethyl ether, Propylene glycol monomethyl ether, diethylene glycol monobutyl ether, diethylene glycol dibutyl ether, etc.), dialkyl ether (dimethyl ether, diethyl ether, dibutyl ether, etc.), alkyl aryl ether (anisole), tetrahydrofuran, dioxane (1,2-, 1,3) And 1,4-isomers), diethoxyethane, tetraethylene glycol dimethyl ether (tetraglyme), triethylene glycol dimethyl ether (triglyme), tetraethylene glycol monomethyl ether, triethylene glycol monomethyl ether, tetraethylene glycol and A triethylene glycol is mentioned.

Examples of the amide compound solvent include N, N-dimethylformamide, 1-methyl-2-pyrrolidone, 2-pyrrolidinone, 1,3-dimethyl-2-imidazolidinone, 2-pyrrolidinone, ε-caprolactam, formamide, N -Methylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpropanamide, hexamethylphosphoric triamide and the like.

Examples of the amino compound solvent include triethylamine and tributylamine.

Examples of the ketone compound solvent include acetone, methyl ethyl ketone, diethyl ketone, ethyl propyl ketone, dipropyl ketone, dibutyl ketone, dipentyl ketone, dihexyl ketone, and cyclohexanone.

Examples of ester compound solvents include methyl acetate, ethyl acetate, propyl acetate, butyl acetate, pentyl acetate, hexyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate. Butyl butyrate, pentyl butyrate, methyl valerate, ethyl valerate, propyl valerate, butyl valerate, methyl caproate, ethyl caproate, propyl caproate and butyl caproate.

Examples of the carbonate compound solvent include ethylene carbonate, dimethyl carbonate, and diethyl carbonate.

Examples of the aromatic compound solvent include benzene, toluene, xylene, mesitylene and the like.

Examples of the aliphatic compound solvent include hexane, heptane, cyclohexane, methylcyclohexane, octane, pentane, and cyclopentane.

Examples of the nitrile compound solvent include acetonitrile, propyronitrile, butyronitrile, and the like.

The dispersion medium preferably has a boiling point of 50 ° C. or higher, more preferably 70 ° C. or higher at normal pressure (1 atm). The upper limit is preferably 250 ° C. or lower, and more preferably 220 ° 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.

In the present invention, among them, ether compound solvents, aromatic compound solvents, and aliphatic compound solvents are preferably used. A combination of an inorganic dehydrating agent and an ether compound solvent, an aromatic compound solvent or an aliphatic compound solvent is preferable because the dehydrating agent can be maintained without being fixed. Moreover, since it mixes in a wide ratio, the combination of an organic type dehydrating agent and an ether compound solvent, a ketone compound solvent, an ester solvent, an aromatic compound solvent or an aliphatic compound solvent is preferable.
Of the ether compound solvents, diethyl ether, dimethoxyethane, ethylphenyl ether, tetrahydrofuran and 1,4-dioxane are preferred. Of these, toluene and xylene are preferred as the aromatic compound solvent. Among them, heptane and octane are preferable as the aliphatic compound solvent.

The content of the dispersion medium in the solid electrolyte composition of the present invention is not particularly limited, but is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, and particularly preferably 40 to 60% by mass.

The dispersion medium is contained in the solid electrolyte composition, but is preferably removed in the process of producing the solid electrolyte-containing sheet or the all-solid secondary battery and does not remain in the solid electrolyte-containing sheet or the all-solid-state secondary battery. A part of the dispersion medium may remain in the solid electrolyte-containing sheet or the all-solid secondary battery. When remaining, the allowable amount of the residual amount in the solid electrolyte-containing sheet or the all-solid secondary battery of these dispersion media is 5% by mass or less, more preferably 1% by mass or less, and more preferably 0.1% by mass or less. More preferred is 0.05% by mass or less. Although the lower limit is not particularly defined, it is practical that it is 1 ppb or more (mass basis).

(Active material (D))
The solid electrolyte composition of the present invention may contain an active material (D) capable of inserting and releasing ions of metal elements belonging to Group 1 or Group 2 of the Periodic Table. Hereinafter, the active material (D) is also simply referred to as an active material.
Examples of the active material include a positive electrode active material and a negative electrode active material, and a transition metal oxide that is a positive electrode active material or a metal oxide that is a negative electrode active material is preferable.
In the present invention, a solid electrolyte composition containing an active material (positive electrode active material, negative electrode active material) may be referred to as an electrode composition (positive electrode composition, negative electrode composition).

-Positive electrode active material-
The positive electrode active material that may be contained in the solid electrolyte composition of the present invention is preferably one that can reversibly insert and release lithium ions. The material is not particularly limited as long as it has the above characteristics, and may be a transition metal oxide, an organic substance, an element that can be complexed with Li, such as sulfur, or a complex of sulfur and metal.
Among them, as the positive electrode active material, it is preferable to use a transition metal oxide, and a transition metal oxide having a transition metal element M ^a (one or more elements selected from Co, Ni, Fe, Mn, Cu and V). More preferred. In addition, this transition metal oxide includes an element M ^b (an element of the first (Ia) group of the metal periodic table other than lithium, an element of the second (IIa) group, Al, Ga, In, Ge, Sn, Pb, Elements such as Sb, Bi, Si, P or B) may be mixed. The mixing amount is preferably 0 ~ 30 mol% relative to the amount of the transition metal element ^{M a (100mol%).} Those synthesized by mixing so that the molar ratio of Li / Ma is 0.3 to 2.2 are more preferable.
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 and (ME) lithium-containing transition metal silicate compounds.

(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 (lithium nickel cobalt aluminate [NCA]), LiNi _1/3 Co _1/3 Mn _1/3 O ₂ (nickel manganese lithium cobaltate [NMC]) and LiNi _0.5 Mn _0.5 O ₂ (manganese) Lithium nickelate).
Specific examples of transition metal oxides having (MB) spinel structure include LiMn ₂ O ₄ (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 is mentioned.
Examples of (MC) lithium-containing transition metal phosphate compounds include olivine-type phosphate iron 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).
(MD) as the 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 and _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, and Li ₂ CoSiO ₄ .
In the present invention, a transition metal oxide having a (MA) layered rock salt structure is preferable, and LCO, LMO, NCA or NMC is more preferable.

The shape of the positive electrode active material is not particularly limited, but is preferably particulate. The volume average particle diameter (sphere conversion average particle diameter) of the positive electrode active material is not particularly limited. For example, the thickness can be 0.1 to 50 μm. 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 diameter (sphere-converted average particle diameter) of the positive electrode active material particles can be measured using a laser diffraction / scattering particle size distribution analyzer LA-920 (trade name, manufactured by HORIBA).

The positive electrode active materials may be used alone or in combination of two or more.
When forming the positive electrode active material layer, the mass (mg) (weight per unit area) of the positive electrode active material per unit area (cm ² ) of the positive electrode active material layer is not particularly limited. This can be determined as appropriate according to the designed battery capacity.

The content of the positive electrode active material in the solid electrolyte composition is not particularly limited, and is preferably 10 to 95% by mass, more preferably 30 to 90% by mass, and even more preferably 50 to 85% by mass at 100% by mass. Preferably, it is 55 to 80% by mass.

-Negative electrode active material-
The negative electrode active material that may be contained in the solid electrolyte composition of the present invention is preferably one that can reversibly insert and release lithium ions. The material is not particularly limited as long as it has the above characteristics, and is a carbonaceous material, a metal oxide such as tin oxide, a silicon oxide, a metal composite oxide, a lithium simple substance and a lithium alloy such as a lithium aluminum alloy, and , Metals such as Sn, Si, Al, and In that can form an alloy with lithium. Among these, a carbonaceous material or a lithium composite oxide is preferably used from the viewpoint of reliability. 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. For example, various synthetics such as petroleum pitch, carbon black such as acetylene black (AB), graphite (natural graphite, artificial graphite such as vapor-grown graphite), PAN (polyacrylonitrile) -based resin, furfuryl alcohol resin, etc. The carbonaceous material which baked resin can be mentioned. Furthermore, various carbon fibers such as PAN-based carbon fiber, cellulose-based carbon fiber, pitch-based carbon fiber, vapor-grown carbon fiber, dehydrated PVA (polyvinyl alcohol) -based carbon fiber, lignin carbon fiber, glassy carbon fiber, and activated carbon fiber. Examples thereof include mesophase microspheres, graphite whiskers, and flat graphite.

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 a peak in the region of 20 ° to 40 ° in terms of 2θ, and is a crystalline diffraction line. You may have.

Among the compound group consisting of the amorphous oxide and the chalcogenide, the amorphous oxide of the metalloid element and the chalcogenide are more preferable, and elements of Groups 13 (IIIB) to 15 (VB) of the periodic table, Al , Ga, Si, Sn, Ge, Pb, Sb and Bi are used alone or in combination of two or more thereof, and chalcogenides are particularly preferable. 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 ₈ Bi ₂ O ₃ , Sb ₂ O ₈ Si ₂ O ₃ , Bi ₂ O ₄ , SnSiO ₃ , GeS, SnS, SnS ₂ , PbS, PbS ₂ , Sb ₂ S ₃ , Sb ₂ S ₅ and SnSiS ₃ are preferred. Moreover, these may be a complex oxide with lithium oxide, for example, Li ₂ SnO ₂ .

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 occlusion and release of lithium ions, and the deterioration of the electrode is suppressed, and the lithium ion secondary This is preferable in that the battery life can be improved.

In the present invention, it is also preferable to apply a Si-based negative electrode. In general, a Si negative electrode can occlude more Li ions than a carbon negative electrode (such as graphite and acetylene black). That is, the amount of occlusion of Li ions per unit mass increases. Therefore, the battery capacity can be increased. As a result, there is an advantage that the battery driving time can be extended.

The shape of the negative electrode active material is not particularly limited, but is preferably particulate. The average particle size of the negative electrode active material is preferably 0.1 to 60 μm. In order to obtain a predetermined particle size, a normal 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, and a sieve are 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 diameter, 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 average particle diameter of the negative electrode active material particles can be measured by the same method as the above-described method for measuring the volume average particle diameter of the positive electrode active material.

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.

The said negative electrode active material may be used individually by 1 type, or may be used in combination of 2 or more type.
When the negative electrode active material layer is formed, the mass (mg) (weight per unit area) of the negative electrode active material per unit area (cm ² ) of the negative electrode active material layer is not particularly limited. This can be determined as appropriate according to the designed battery capacity.

The content of the negative electrode active material in the solid electrolyte composition is not particularly limited, and is preferably 10 to 80% by mass, and more preferably 20 to 80% by mass with a solid content of 100% by mass.

The surfaces of the positive electrode active material and the negative electrode active material may be coated with another metal oxide. Examples of the surface coating agent include metal oxides containing Ti, Nb, Ta, W, Zr, Al, Si, or Li. Specific examples include spinel titanate, tantalum-based oxides, niobium-based oxides, lithium niobate-based compounds, and the like. Specifically, Li ₄ Ti ₅ O ₁₂ , Li ₂ Ti ₂ O ₅ , LiTaO _3. , LiNbO ₃ , LiAlO ₂ , Li ₂ ZrO ₃ , Li ₂ WO ₄ , Li ₂ TiO ₃ , Li ₂ B ₄ O ₇ , Li ₃ PO ₄ , Li ₂ MoO ₄ , Li ₃ BO ₃ , LiBO ₂ , Li ₂ CO ₃ , Li ₂ SiO ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , Al ₂ O ₃ , B ₂ O _{3 and the} like.
Moreover, the electrode surface containing a positive electrode active material or a negative electrode active material may be surface-treated with sulfur or phosphorus.
Furthermore, the particle surface of the positive electrode active material or the negative electrode active material may be subjected to a surface treatment with actinic light or an active gas (plasma or the like) before and after the surface coating.

(Binder (E))
The solid electrolyte composition of the present invention may contain a binder (E). Hereinafter, the binder (E) is also simply referred to as a binder.
The binder used in the present invention is not particularly limited as long as it is an organic polymer.
The binder that can be used in the present invention is not particularly limited, and for example, a binder made of the resin described below is preferable.

Examples of the fluorine-containing resin include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and a copolymer of polyvinylidene fluoride and hexafluoropropylene (PVdF-HFP).
Examples of the hydrocarbon-based thermoplastic resin include polyethylene, polypropylene, styrene butadiene rubber (SBR), hydrogenated styrene butadiene rubber (HSBR), butylene rubber, acrylonitrile butadiene rubber, polybutadiene, and polyisoprene.
Examples of the acrylic resin include various (meth) acrylic monomers, (meth) acrylamide monomers, and copolymers of these monomers (preferably a copolymer of acrylic acid and methyl acrylate). It is done.
Further, a copolymer (copolymer) with other vinyl monomers is also preferably used. Examples thereof include a copolymer of methyl (meth) acrylate and styrene, a copolymer of methyl (meth) acrylate and acrylonitrile, and a copolymer of butyl (meth) acrylate, acrylonitrile, and styrene. In the present specification, the copolymer may be either a statistical copolymer or a periodic copolymer, and a block copolymer is preferred.
Examples of other resins include polyurethane resin, polyurea resin, polyamide resin, polyimide resin, polyester resin, polyether resin, polycarbonate resin, and cellulose derivative resin.
These may be used individually by 1 type, or may be used in combination of 2 or more type.

The binder used in the present invention exhibits strong binding properties (inhibition of peeling from the current collector and improvement in cycle life due to binding at the solid interface), so that the above-mentioned acrylic resin, polyurethane resin, polyurea resin, polyimide resin are used. It is preferably at least one selected from the group consisting of fluorine-containing resins and hydrocarbon-based thermoplastic resins.

The binder used in the present invention preferably has a polar group in order to improve wettability and adsorptivity to the particle surface. The polar group is preferably a monovalent group containing a hetero atom, for example, a monovalent group containing a structure in which any one of an oxygen atom, a nitrogen atom and a sulfur atom is bonded to a hydrogen atom. Specific examples include a carboxy group, A hydroxy group, an amino group, a phosphate group, and a sulfo group are mentioned.

The shape of the binder is not particularly limited, and may be particulate or indefinite in the solid electrolyte composition, the solid electrolyte-containing sheet, or the all-solid secondary battery.
In the present invention, it is preferable from the viewpoint of dispersion stability of the solid electrolyte composition that the binder is particles insoluble in the dispersion medium. Here, “the binder is an insoluble particle in the dispersion medium” means that the average particle diameter does not decrease by 5% or more even when added to the dispersion medium at 30 ° C. and left to stand for 24 hours. It is preferably 3% or less, more preferably 1% or less.
In the state where the binder particles are not dissolved at all in the dispersion medium, the amount of change in the average particle diameter with respect to that before the addition is 0%.
In addition, the binder in the solid electrolyte composition is preferably a nanoparticle having an average particle diameter of 10 to 1000 nm in order to suppress a decrease in interparticle ion conductivity of the inorganic solid electrolyte.
The average particle size of the binder can be calculated by the method described in the Examples section below.

The binder may be composed of one compound or a combination of two or more compounds. When the binder is a particle, the particle itself may not be a uniform dispersion but may be a core-shell shape or a hollow shape. Moreover, you may enclose organic substance and an inorganic substance in the core part which forms the inside of a binder. Examples of the organic substance included in the core include a dispersion medium, a dispersant, a lithium salt, an ionic liquid, and a conductive auxiliary agent described later.

The average particle size of the binder particles used in the present invention is based on the measurement conditions and definitions described below unless otherwise specified.
The binder particles are prepared by diluting a 1% by mass dispersion in a 20 ml sample bottle using an arbitrary solvent (dispersion medium used for preparing the solid electrolyte composition, for example, octane). The diluted dispersion sample is irradiated with 1 kHz ultrasonic waves for 10 minutes and used immediately after that. Using this dispersion liquid sample, using a laser diffraction / scattering particle size distribution measuring device LA-920 (trade name, manufactured by HORIBA), data was acquired 50 times using a quartz cell for measurement at a temperature of 25 ° C., Let the obtained volume average particle diameter be an average particle diameter. For other detailed conditions, the description of JISZ8828: 2013 “Particle Size Analysis—Dynamic Light Scattering Method” is referred to as necessary. Five samples are prepared for each level and measured, and the average value is adopted.
In addition, the measurement from the produced all-solid-state secondary battery is performed, for example, after disassembling the battery and peeling off the electrode, then measuring the electrode material according to the method for measuring the average particle diameter of the polymer particles, This can be done by eliminating the measured value of the average particle diameter of the particles other than the polymer particles that have been measured.

In addition, a commercial item can be used for the binder used for this invention. Moreover, it can also prepare by a conventional method.

The water concentration of the polymer constituting the binder used in the present invention is preferably 100 ppm (mass basis) or less.
Moreover, the polymer which comprises the binder used for this invention may be used in a solid state, and may be used in the state of a polymer particle dispersion or a polymer solution.

The mass average molecular weight of the polymer constituting the binder used in the present invention is preferably 10,000 or more, more preferably 20,000 or more, and further preferably 30,000 or more. As an upper limit, 1,000,000 or less is preferable, 200,000 or less is more preferable, and 100,000 or less is more preferable.

The content of the binder in the solid electrolyte composition is 0.01% by mass with respect to 100% by mass of the solid component, considering good reduction in interface resistance and its maintainability when used in an all-solid secondary battery. The above is preferable, 0.1% by mass or more is more preferable, and 1% by mass or more is more preferable. As an upper limit, from a viewpoint of a battery characteristic, 10 mass% or less is preferable, 5 mass% or less is more preferable, and 3 mass% or less is further more preferable.
In the present invention, the mass ratio of the total mass (total amount) of the inorganic solid electrolyte and the active material to the mass of the binder [(mass of the inorganic solid electrolyte + mass of the active material) / mass of the binder] is 1,000 to 1. A range is preferred. This ratio is more preferably 500 to 2, and further preferably 100 to 10.

(Dispersant)
The solid electrolyte composition of the present invention may contain a dispersant. Even when the concentration of either the electrode active material or the inorganic solid electrolyte is high by adding a dispersant, or even when the particle diameter is small and the surface area is increased, the aggregation is suppressed, and the uniform active material layer and solid electrolyte layer Can be formed. As the dispersant, those usually used for all-solid secondary batteries can be appropriately selected and used. In general, compounds intended for particle adsorption and steric repulsion and / or electrostatic repulsion are preferably used.

(Lithium salt)
The solid electrolyte composition of the present invention may contain a lithium salt.
The lithium salt is not particularly limited, and for example, lithium salts described in paragraphs 0082 to 0085 of JP-A-2015-088486 are preferable.
The content of the lithium salt is preferably 0 part by mass or more and more preferably 5 parts by mass or more with respect to 100 parts by mass of the inorganic solid electrolyte. As an upper limit, 50 mass parts or less are preferable, and 20 mass parts or less are more preferable.

(Ionic liquid)
The solid electrolyte composition of the present invention may contain an ionic liquid in order to further improve the ionic conductivity of the solid electrolyte-containing sheet. Although it does not specifically limit as an ionic liquid, From the viewpoint of improving an ionic conductivity effectively, what melt | dissolves the lithium salt mentioned above is preferable. For example, the compound which consists of a combination of the following cation and an anion is mentioned.

(I) Cation As a cation, an imidazolium cation having the following substituent, a pyridinium cation having the following substituent, a piperidinium cation having the following substituent, a pyrrolidinium cation having the following substituent, Morpholinium cations having the following substituents, phosphonium cations having the following substituents, or quaternary ammonium cations having the following substituents.
As the cation, one kind of these cations may be used alone, or two or more kinds may be used in combination.
Preferably, it is a quaternary ammonium cation, a piperidinium cation or a pyrrolidinium cation.
As the substituent, an alkyl group (an alkyl group having 1 to 8 carbon atoms is preferable, and an alkyl group having 1 to 4 carbon atoms is more preferable), a hydroxyalkyl group (a hydroxyalkyl group having 1 to 3 carbon atoms is preferable). An alkyloxyalkyl group (preferably an alkyloxyalkyl group having 2 to 8 carbon atoms, more preferably an alkyloxyalkyl group having 2 to 4 carbon atoms), an ether group, an allyl group, an aminoalkyl group (1 to 8 carbon atoms). And an aryl group (an aryl group having 6 to 12 carbon atoms is more preferable, and an aryl group having 6 to 8 carbon atoms is more preferable). Can be mentioned. The substituent may form a cyclic structure containing a cation moiety. These substituents may further have the above substituent P. The ether group is used in combination with other substituents. Examples of such a substituent include an alkyloxy group and an aryloxy group.

(Ii) Anions As anions, chloride ions, bromide ions, iodide ions, boron tetrafluoride ions, nitrate ions, dicyanamide ions, acetate ions, iron tetrachloride ions, bis (trifluoromethanesulfonyl) imide ions, bis ( Fluorosulfonyl) imide ion, bis (perfluorobutylmethanesulfonyl) imide ion, allyl sulfonate ion, hexafluorophosphate ion, or trifluoromethane sulfonate ion.
As the anion, these anions may be used alone or in combination of two or more.
Preferred are boron tetrafluoride ion, bis (trifluoromethanesulfonyl) imide ion, bis (fluorosulfonyl) imide ion, hexafluorophosphate ion, dicyanamide ion or allyl sulfonate ion, and more preferred is bis (trifluoromethanesulfonyl) imide ion. Bis (fluorosulfonyl) imide ion or allyl sulfonate ion.

Examples of the ionic liquid include 1-allyl-3-ethylimidazolium bromide, 1-ethyl-3-methylimidazolium bromide, 1- (2-hydroxyethyl) -3-methylimidazolium bromide, 1- ( 2-methoxyethyl) -3-methylimidazolium bromide, 1-octyl-3-methylimidazolium chloride, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium tetrafluoroborate, 1- Ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide, 1-ethyl-3-methylimidazolium bistrifluoromethanesulfonic acid, 1-ethyl- 3-methylimidazolium dicyanamide, 1- Tyl-1-methylpyrrolidinium bis (trifluoromethanesulfonyl) imide, trimethylbutylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethane Sulfonyl) imide, N- (2-methoxyethyl) -N-methylpyrrolidinium tetrafluoroborard, 1-butyl-1-methylpyrrolidinium imidazolium bis (fluorosulfonyl) imide, (2-acryloylethyl) trimethylammonium Bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-methylpyrrolidinium allyl sulfonate, 1-ethyl-3-methylimidazolium allyl sulfonate, or trihexyl tetradecylphosphoni chloride Beam, and the like.
The content of the ionic liquid is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and particularly preferably 1 part by mass or more with respect to 100 parts by mass of the inorganic solid electrolyte. As an upper limit, 50 mass parts or less are preferable, 20 mass parts or less are more preferable, and 10 mass parts or less are especially preferable.
The mass ratio of the lithium salt to the ionic liquid is preferably 1:20 to 20: 1, more preferably 1:10 to 10: 1, and particularly preferably 1: 5 to 2: 1.

(Conductive aid)
The solid electrolyte composition of the present invention may contain a conductive additive. There is no restriction | limiting in particular as a conductive support agent, 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.

(Preparation of solid electrolyte composition)
The solid electrolyte composition of the present invention can be prepared by dispersing the inorganic solid electrolyte (A) in the presence of the dispersion medium (C) to form a slurry.
Slurry can be performed by mixing an inorganic solid electrolyte and a dispersion medium using various mixers. The mixing apparatus is not particularly limited, and examples thereof include a ball mill, a bead mill, a planetary mixer, a blade mixer, a roll mill, a kneader, and a disk mill. The mixing conditions are not particularly limited. For example, when a ball mill is used, the mixing is preferably performed at 150 to 700 rpm (rotation per minute) for 1 to 24 hours.
When preparing a solid electrolyte composition containing components such as an active material and a particle dispersant, it may be added and mixed simultaneously with the dispersion step of the inorganic solid electrolyte (A), or may be added and mixed separately. Also good. The dehydrating agent (B) may be added and mixed simultaneously with the dispersion step of the above-mentioned inorganic solid electrolyte (A) and / or components such as the active material and the particle dispersing agent, or may be added and mixed separately. . Among these, the inorganic dehydrating agent is preferably added after dispersing and / or mixing components other than the inorganic dehydrating agent constituting the solid electrolyte composition, and the organic dehydrating agent is an organic component constituting the solid electrolyte composition. It is preferable to add after dispersing and / or mixing components other than the system dehydrating agent.

[All-solid-state secondary battery sheet]
The solid electrolyte-containing sheet of the present invention can be suitably used for an all-solid-state secondary battery, and includes various modes depending on the application. For example, a sheet preferably used for a solid electrolyte layer (also referred to as a solid electrolyte sheet for an all-solid secondary battery), a sheet preferably used for an electrode or a laminate of an electrode and a solid electrolyte layer (an electrode sheet for an all-solid secondary battery) Etc. In the present invention, these various sheets may be collectively referred to as an all-solid secondary battery sheet.

The all-solid-state secondary battery sheet is a sheet having a solid electrolyte layer or an active material layer (electrode layer) on a base material. The all-solid-state secondary battery sheet may have other layers as long as it has a base material and a solid electrolyte layer or an active material layer. It is classified as a secondary battery electrode sheet. Examples of other layers include a protective layer, a current collector, and a coat layer (current collector, solid electrolyte layer, active material layer) and the like.
Examples of the solid electrolyte sheet for an all-solid secondary battery include a sheet having a solid electrolyte layer and a protective layer in this order on a base material.
The substrate is not particularly limited as long as it can support the solid electrolyte layer, and examples thereof include materials described in the current collector, sheet materials (plate bodies) such as organic materials and inorganic materials, and the like. Examples of the organic material include various polymers, and specific examples include polyethylene terephthalate, polypropylene, polyethylene, and cellulose. Examples of the inorganic material include glass and ceramic.

The thickness of the solid electrolyte layer of the all-solid-state secondary battery sheet is the same as the thickness of the solid electrolyte layer described in the above-described all-solid-state secondary battery of the present invention.
In this sheet, the filtrate of the solid electrolyte composition of the present invention is formed (applied and dried) on a base material (which may be via another layer) to form a solid electrolyte layer on the base material. Is obtained.
Here, the solid electrolyte composition of the present invention can be prepared by the above-described method.

The electrode sheet for an all-solid-state secondary battery of the present invention (also simply referred to as “electrode sheet”) is formed on a metal foil as a current collector for forming the active material layer of the all-solid-state secondary battery of the present invention. An electrode sheet having an active material layer. This electrode sheet is usually a sheet having a current collector and an active material layer, but an embodiment having a current collector, an active material layer, and a solid electrolyte layer in this order, and a current collector, an active material layer, and a solid electrolyte The aspect which has a layer and an active material layer in this order is also included.
The layer thickness of each layer constituting the electrode sheet is the same as the layer thickness of each layer described in the above-described all solid state secondary battery of the present invention. Moreover, the structure of each layer which comprises an electrode sheet is the same as the structure of each layer demonstrated in the postscript and the all-solid-state secondary battery of this invention.
The electrode sheet can be obtained by forming a solid electrolyte composition-containing filtrate of the present invention on a metal foil (coating and drying) to form an active material layer on the metal foil. The method for preparing the solid electrolyte composition containing the active material is the same as the method for preparing the solid electrolyte composition except that the active material is used.

[All-solid secondary battery]
The all solid state secondary battery of the present invention has a positive electrode, a negative electrode facing the positive electrode, and a solid electrolyte layer between the positive electrode and the negative electrode. The positive electrode has a positive electrode active material layer on a positive electrode current collector. The negative electrode has a negative electrode active material layer on a negative electrode current collector.
At least one of the negative electrode active material layer, the positive electrode active material layer, and the solid electrolyte layer is preferably formed using the solid electrolyte composition of the present invention.
The active material layer and / or the solid electrolyte layer formed using the solid electrolyte composition are preferably basically the same as those in the solid content of the solid electrolyte composition with respect to the component types to be contained and the content ratio thereof. is there. However, in the present invention, since the solid electrolyte composition is filtered and used to form each layer, when the dehydrating agent is filtered off, the content may be different between the solid electrolyte composition and each layer.
Hereinafter, a preferred embodiment of the present invention will be described with reference to FIG. 1, but the present invention is not limited to this.

[Positive electrode active material layer, solid electrolyte layer, negative electrode active material layer]
In the all-solid-state secondary battery 10, any of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer is formed of the solid electrolyte-containing sheet of the present invention.
That is, when the solid electrolyte layer 3 is formed of the solid electrolyte-containing sheet of the present invention, the solid electrolyte layer 3 includes an inorganic solid electrolyte and a dehydrating agent. The solid electrolyte layer usually does not contain a positive electrode active material and / or a negative electrode active material. In the solid electrolyte layer 3, since the dehydrating agent contained between the solid particles in the inorganic solid electrolyte and the adjacent active material reacts with water, deterioration of the inorganic solid electrolyte is suppressed. Even when used after storage, the all-solid-state secondary battery 10 is excellent in battery voltage.

When the positive electrode active material layer 4 and / or the negative electrode active material layer 2 is formed of the solid electrolyte-containing sheet of the present invention containing an active material, that is, an electrode sheet, the positive electrode active material layer 4 and the negative electrode active material layer 2 are , Each including a positive electrode active material or a negative electrode active material, and further including an inorganic solid electrolyte and a dehydrating agent. When the active material layer contains an inorganic solid electrolyte, the ionic conductivity can be improved. In the active material layer, the dehydrating agent present between the solid particles reacts with water, so that the deterioration of the inorganic solid electrolyte is suppressed. 10 is excellent in battery voltage.
The inorganic solid electrolyte and the dehydrating agent contained in the positive electrode active material layer 4, the solid electrolyte layer 3, and the negative electrode active material layer 2 may be the same or different from each other.

In the present invention, any one of the negative electrode active material layer, the positive electrode active material layer, and the solid electrolyte layer in the all-solid-state secondary battery contains a solid electrolyte containing the dehydrating agent and solid particles such as an inorganic solid electrolyte. It is produced using a sheet.

[Current collector (metal foil)]
The positive electrode current collector 5 and the negative electrode current collector 1 are preferably electronic conductors.
In the present invention, either or both of the positive electrode current collector and the negative electrode current collector may be simply referred to as a current collector.
Materials for forming the positive electrode current collector include aluminum, aluminum alloy, stainless steel, nickel and titanium, as well as the surface of aluminum or stainless steel treated with carbon, nickel, titanium or silver (formation of a thin film) Among them, aluminum and aluminum alloys are more preferable.
In addition to aluminum, copper, copper alloy, stainless steel, nickel and titanium, etc., the material for forming the negative electrode current collector is treated with carbon, nickel, titanium or silver on the surface of aluminum, copper, copper alloy or stainless steel. What was made to do is preferable, and aluminum, copper, copper alloy, and stainless steel are more preferable.

The current collector is usually in the form of a film sheet, but a net, a punched one, a lath, a porous body, a foam, a fiber group molded body, or the like can also be used.
The thickness of the current collector is not particularly limited, but is preferably 1 to 500 μm. Moreover, it is also preferable that the current collector surface is roughened by surface treatment.

In the present invention, a functional layer, a member, or the like is appropriately interposed or disposed between or outside each of the negative electrode current collector, the negative electrode active material layer, the solid electrolyte layer, the positive electrode active material layer, and the positive electrode current collector. May be. Each layer may be composed of a single layer or a plurality of layers.

[Case]
The basic structure of the all-solid-state secondary battery can be manufactured by arranging each of the above layers. 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). When using a metallic thing, the thing made from an aluminum alloy and stainless steel can be mentioned, for example. The metallic housing is preferably divided into a positive-side housing and a negative-side housing, and electrically connected to the positive current collector and the negative current collector, respectively. The casing on the positive electrode side and the casing on the negative electrode side are preferably joined and integrated through a gasket for preventing a short circuit.

[Production of solid electrolyte-containing sheet]
The solid electrolyte-containing sheet of the present invention contains an inorganic solid electrolyte (A) having conductivity of ions of metals belonging to Group 1 or Group 2 of the periodic table, and a dehydrating agent (B), thereby improving battery performance. In order to minimize the effect of the dehydrating agent, the content of the dehydrating agent is preferably 5% by mass or less. Although there is no restriction | limiting in particular in a minimum, It is preferable that it is 0.1% or more.

It is also considered that the dehydrating agent is preferably present in the slurry and removed from the solid electrolyte-containing sheet. In the case of an inorganic dehydrating agent, there is a risk of inhibiting the formation of the interface between the active material and the inorganic solid electrolyte. If the dehydrating agent is excessively contained in the solid electrolyte-containing sheet, there is a concern about the effect on battery performance. is there. Even in the case of an organic dehydrating agent, by-products generated by reaction with water may further react with the inorganic solid electrolyte, and if the solid electrolyte-containing sheet contains excessive dehydrating agent, battery performance will be reduced. There is concern about making it worse.
However, if the dehydrating agent contained in the solid electrolyte-containing sheet is a predetermined amount, not only the battery performance is not lowered, but also the battery performance can be improved.
In the present invention, the solid electrolyte-containing sheet preferably contains an organic dehydrating agent.
For example, when an organic dehydrating agent in which a by-product generated by the reaction with water is an acid (carboxylic acid, sulfonic acid, phosphoric acid, etc.) is used, the acid is harmless to the inorganic solid electrolyte. Therefore, these organic dehydrating agents remain in the solid electrolyte-containing sheet, so that not only the slurry but also the water resistance of the solid electrolyte-containing sheet can be improved, and the all-solid-state secondary battery can be obtained without degrading the battery performance. The battery voltage can be improved.
In order to prevent the dehydrating agent from being contained in the solid electrolyte-containing sheet, for example, it is volatilized at the time of heat drying in the sheet manufacturing process.

The solid electrolyte-containing sheet of the present invention includes a step of filtering a solid electrolyte composition containing an inorganic solid electrolyte (A), a dehydrating agent (B), and a dispersion medium (C), and the filtrate obtained in the above step. It can manufacture by passing through the process of apply | coating on a base material, and the process of heat-drying.
In addition, content of the dehydrating agent which is not melt | dissolved in a dispersion medium in a solid electrolyte containing sheet can be adjusted with the said filtration process. Specifically, for example, the content of the inorganic dehydrating agent in the solid electrolyte-containing sheet is prepared by adjusting the amount of the dehydrating agent that is collected by the pore size of the filter used for filtration. Here, the dehydrating agent that does not dissolve in the dispersion medium is a dehydrating agent that maintains a solid in the dispersion medium, and specifically includes an inorganic dehydrating agent.
By the said aspect, the sheet | seat for all-solid-state secondary batteries which is a sheet | seat which has a base material and a solid electrolyte layer can be produced.
In addition, about the process of application | coating etc., the method as described in manufacture of the following all-solid-state secondary battery can be used.
The solid electrolyte-containing sheet may contain a dispersion medium within a range that does not affect battery performance. Specifically, you may contain 1 ppm or more and 10000 ppm or less in the total mass.

[Manufacture of all-solid-state secondary battery and electrode sheet for all-solid-state secondary battery]
Manufacture of the all-solid-state secondary battery and the electrode sheet for all-solid-state secondary batteries can be performed by a conventional method. Specifically, the all-solid-state secondary battery and the electrode sheet for the all-solid-state secondary battery are filtrates obtained by filtering the solid electrolyte composition of the present invention with, for example, a Teflon (registered trademark) mesh (hereinafter referred to as solid electrolyte). It is also referred to as a filtrate of a composition. This will be described in detail below. Here, each layer in the all-solid-state secondary battery of the present invention only needs to be formed of any one of the solid electrolyte compositions of the present invention. Can be read as “a solid electrolyte composition other than the solid electrolyte composition of the present invention”.

The all-solid-state secondary battery of the present invention includes a method of applying (interposing) the filtrate of the solid electrolyte composition of the present invention onto a metal foil serving as a current collector and forming (forming) a coating film. Can be manufactured.
For example, a positive electrode active material layer is formed by applying a filtrate of a solid electrolyte composition containing a positive electrode active material as a positive electrode material (positive electrode composition) on a metal foil that is a positive electrode current collector. A positive electrode sheet for a solid secondary battery is prepared. Next, a solid electrolyte composition filtrate for forming a solid electrolyte layer is applied on the positive electrode active material layer to form a solid electrolyte layer. Further, a solid electrolyte composition filtrate containing a negative electrode active material is applied as a negative electrode material (negative electrode composition) on the solid electrolyte layer to form a negative electrode active material layer. An all-solid secondary battery having a structure in which a solid electrolyte layer is sandwiched between a positive electrode active material layer and a negative electrode active material layer is obtained by stacking a negative electrode current collector (metal foil) on the negative electrode active material layer. Can do. If necessary, this can be enclosed in a housing to obtain a desired all-solid secondary battery.
Moreover, the formation method of each layer is reversed, and a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer are formed on the negative electrode current collector, and the positive electrode current collector is stacked to manufacture an all-solid secondary battery. You can also

Another method includes the following method. That is, a positive electrode sheet for an all-solid secondary battery is produced as described above. Also, a negative electrode active material layer is formed by applying a solid electrolyte composition filtrate containing a negative electrode active material as a negative electrode material (negative electrode composition) on a metal foil as a negative electrode current collector. A negative electrode sheet for a solid secondary battery is prepared. Next, a solid electrolyte layer is formed on one of the active material layers of these sheets as described above. Furthermore, the other of the positive electrode sheet for an all solid secondary battery and the negative electrode sheet for an all solid secondary battery is laminated on the solid electrolyte layer so that the solid electrolyte layer and the active material layer are in contact with each other. In this way, an all-solid secondary battery can be manufactured.
Another method includes the following method. That is, as described above, a positive electrode sheet for an all-solid secondary battery and a negative electrode sheet for an all-solid secondary battery are produced. Separately from this, a solid electrolyte composition filtrate is applied on a substrate to produce a solid electrolyte sheet for an all-solid-state secondary battery comprising a solid electrolyte layer. Furthermore, it laminates | stacks so that the solid electrolyte layer peeled off from the base material may be pinched | interposed with the positive electrode sheet for all-solid-state secondary batteries, and the negative electrode sheet for all-solid-state secondary batteries. In this way, an all-solid secondary battery can be manufactured.

An all-solid-state secondary battery can also be manufactured by a combination of the above forming methods. For example, as described above, a positive electrode sheet for an all-solid secondary battery, a negative electrode sheet for an all-solid secondary battery, and a solid electrolyte sheet for an all-solid secondary battery are produced. Then, after laminating the solid electrolyte layer peeled off from the base material on the negative electrode sheet for an all solid secondary battery, an all solid secondary battery can be produced by pasting the positive electrode sheet for the all solid secondary battery. it can. In this method, the solid electrolyte layer can be laminated on the positive electrode sheet for an all-solid secondary battery, and bonded to the negative electrode sheet for an all-solid secondary battery.

(Formation of each layer (film formation))
The method for applying the filtrate of the solid electrolyte composition is not particularly limited, and can be appropriately selected. Examples thereof include coating (preferably wet coating), spray coating, spin coating coating, dip coating, slit coating, stripe coating, and bar coating coating.
At this time, the filtrate of the solid electrolyte composition may be dried after being applied, or may be dried after being applied in multiple layers. The drying temperature is not particularly limited. The lower limit is preferably 30 ° C or higher, more preferably 60 ° C or higher, and still more preferably 80 ° C or higher. The upper limit is preferably 300 ° C. or lower, more preferably 250 ° C. or lower, and further preferably 200 ° C. or lower. By heating in such a temperature range, a dispersion medium can be removed and it can be set as a solid state. Moreover, it is preferable because the temperature is not excessively raised and each member of the all-solid-state secondary battery is not damaged. Thereby, in the all-solid-state secondary battery, excellent overall performance can be exhibited and good binding properties can be obtained.

It is preferable to pressurize each layer or all-solid secondary battery after applying the filtrate of the solid electrolyte composition or after producing the all-solid secondary battery. Moreover, it is also preferable to pressurize in the state which laminated | stacked each layer. An example of the pressurizing method is a hydraulic cylinder press. The applied pressure is not particularly limited and is generally preferably in the range of 50 to 1500 MPa.
Moreover, you may heat the apply | coated solid electrolyte composition simultaneously with pressurization. The heating temperature is not particularly limited, and is generally in the range of 30 to 300 ° C. It is also possible to press at a temperature higher than the glass transition temperature of the inorganic solid electrolyte.
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.
In addition, each composition may be applied simultaneously, and application and drying presses may be performed simultaneously and / or sequentially. You may laminate | stack by transfer after apply | coating to a separate base material.

The atmosphere during pressurization is not particularly limited, and may be any of the following: air, dry air (dew point -20 ° C. or lower), and inert gas (for example, argon gas, helium gas, nitrogen gas).
The pressing time may be a high pressure in a short time (for example, within several hours), or a medium pressure may be applied for a long time (1 day or more). In the case of an all-solid-state secondary battery other than the all-solid-state secondary battery sheet, for example, a restraining tool (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 pressed part such as the 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.

(Initialization)
The all solid state secondary battery manufactured as described above is preferably initialized after manufacture or before use. The initialization is not particularly limited, and can be performed, for example, by performing initial charging / discharging in a state where the press pressure is increased, and then releasing the pressure until the general use pressure of the all-solid secondary battery is reached.

[Use of all-solid-state secondary batteries]

The all solid state secondary battery of the present invention can be applied to various uses. Although there is no particular limitation on the application mode, 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 mobile phone, a cordless phone, a pager, a handy terminal, a mobile fax machine, a mobile phone Copy, portable printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, minidisc, electric shaver, transceiver, electronic notebook, calculator, portable tape recorder, radio, backup power supply, memory card, etc. Others for consumer use include automobiles (electric cars, etc.), electric vehicles, motors, lighting equipment, toys, game equipment, road conditioners, watches, strobes, cameras, medical equipment (pacemakers, hearing aids, shoulder massagers, etc.) . Furthermore, it can be used for various military use and space use. Moreover, it can also combine with a solar cell.

According to a preferred embodiment of the present invention, the following applications are derived.
[1] An all-solid secondary battery in which at least one of a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer contains a lithium salt.
[2] A method for producing an all-solid-state secondary battery, in which the solid electrolyte layer is wet-coated with a slurry filtrate in which a lithium salt and a sulfide-based inorganic solid electrolyte are dispersed by a dispersion medium.
[3] A solid electrolyte composition containing an active material for producing the all-solid secondary battery.
[4] A battery electrode sheet obtained by applying the filtrate of the solid electrolyte composition on a metal foil to form a film.
[5] A method for producing an electrode sheet for a battery, wherein the filtrate of the solid electrolyte composition is applied onto a metal foil to form a film.

As described in [2] and [5] of the preferred embodiments, the preferred methods for producing the all-solid-state secondary battery and the battery electrode sheet of the present invention are both wet processes. Thereby, even in a region where the content of the inorganic solid electrolyte in at least one of the positive electrode active material layer and the negative electrode active material layer is as low as 10% by mass or less, the adhesiveness between the active material and the inorganic solid electrolyte is increased, and an efficient ion conduction path. Can be maintained, and an all-solid-state secondary battery having a high energy density (Wh / kg) and high power density (W / kg) per battery mass can be manufactured.

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 includes an organic (polymer) all-solid-state secondary battery that uses a polymer compound such as polyethylene oxide as an electrolyte, and an inorganic all-solid-state that uses the above-described Li—PS glass, LLT, LLZ, or the like. It is divided into secondary batteries. In addition, application of an organic compound to an inorganic all-solid secondary battery is not hindered, and the organic compound can be applied as a binder or additive for a positive electrode active material, a negative electrode active material, and an inorganic solid electrolyte.
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-described Li—PS glass, 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. When distinguishing from the electrolyte as the above ion transport material, this is called “electrolyte salt” or “supporting electrolyte”. An example of the electrolyte salt is LiTFSI.
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.

Hereinafter, the present invention will be described in more detail based on examples. The present invention is not construed as being limited thereby. In the following examples, “part” and “%” representing the composition are based on mass unless otherwise specified. “Room temperature” means 25 ° C.

<Synthesis of sulfide-based inorganic solid electrolyte>
-Synthesis of Li-PS system glass-
As a sulfide-based inorganic solid electrolyte, T.I. Ohtomo, A .; Hayashi, M .; Tatsumisago, Y. et al. Tsuchida, S .; HamGa, K .; Kawamoto, Journal of Power Sources, 233, (2013), pp231-235 and A.K. Hayashi, S .; Hama, H .; Morimoto, M .; Tatsumisago, T .; Minami, Chem. Lett. , (2001), pp 872-873, Li—PS glass was synthesized.

Specifically, 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 , 3.90 g manufactured by Aldrich, purity> 99%) was weighed, put into an agate mortar, and mixed for 5 minutes using an agate pestle. The mixing ratio of Li ₂ S and P ₂ S ₅ was Li ₂ S: P ₂ S ₅ = 75: 25 in terms of molar ratio.
66 zirconia beads having a diameter of 5 mm were introduced into a 45 mL container (manufactured by Fritsch) made of zirconia, the whole mixture of lithium sulfide and phosphorous pentasulfide was introduced, and the container was sealed under an argon atmosphere. This container is set in a planetary ball mill P-7 (trade name) manufactured by Frichtu, and mechanical milling is performed at a temperature of 25 ° C. and a rotation speed of 510 rpm for 20 hours to obtain a yellow powder sulfide-based inorganic solid electrolyte (Li-P—). S glass) 6.20 g was obtained. The ionic conductivity was 0.28 mS / cm, and the particle diameter was 20.3 μm.

Example 1
<Test>
The ionic conductivity before and after aging of the solid electrolyte composition prepared below was measured, and how much the ionic conductivity decreased before and after aging was evaluated. The test method is described below. The evaluation is described in the column of “Ion conductivity reduction inhibiting effect” in Table 1 below.

<Ion conductivity measurement>
The prepared slurry of the solid electrolyte composition was filtered through a 50 μm Teflon mesh, and then dried at normal pressure (760 mmHg) for 2 hours on a hot plate heated to 100 ° C. in a dry air having a dew point of −60 ° C. About the obtained dry powder, the ionic conductivity was measured by the impedance method. This is defined as ion conductivity (Ia) before aging.

The slurry of the solid electrolyte composition was stirred with a stirrer for 2 weeks in a constant temperature bath at 25 ° C. in an open system under dry air having a dew point of −20 ° C.
The slurry after 2 weeks was filtered through a 50 μm Teflon mesh, dried by the same method as above, and the ionic conductivity of the dried powder was measured by the impedance method. This is defined as ionic conductivity (Ib) after time.

300 mg of the dry powder was packed in a cylinder having a diameter of 14.5 mm to produce a coin-type jig. The sample was sandwiched between jigs capable of applying a pressure of 500 kgf / cm ² between the electrodes from the outside of the coin-type jig, and used for ion conductivity measurement.
Using the coin-type jig obtained above, the ion conductivity under pressure (500 kgf / cm ² ) was determined by an alternating current impedance method in a thermostat at 30 ° C. At this time, the specimen shown in FIG. 2 was used for pressurization of the coin-type jig. 11 is an upper support plate, 12 is a lower support plate, 13 is a coin-type jig, and S is a screw.
The evaluation criteria are shown below. B and above are acceptable levels.

A: 0.9 <(Ib / Ia)
B: 0.7 <(Ib / Ia) ≦ 0.9
C: 0.3 <(Ib / Ia) ≦ 0.7
D: 0.1 <(Ib / Ia) ≦ 0.3
E: (Ib / Ia) ≦ 0.1

<Preparation of each composition>
-Preparation of solid electrolyte composition S-1-
50 zirconia beads having a diameter of 3 mm were put into a 45 mL container made of zirconia (manufactured by Fritsch), 1.5 g of an oxide-based inorganic solid electrolyte LLZ (manufactured by Toshima Seisakusho) and 0.02 g of binder (E-1) were added, As a dispersion medium, 5.3 g of 1,4-dioxane was added. Thereafter, the container was set on a planetary ball mill P-7 (trade name) manufactured by Fritsch, and mixing was continued for 2 hours at a temperature of 25 ° C. and a rotation speed of 300 rpm. Thereafter, 1.0 g of sufficiently dried molecular sieves 4A as a dehydrating agent was added to prepare a solid electrolyte composition S-1.

(2) Preparation of Solid Electrolyte Composition S-2 50 zirconia beads having a diameter of 3 mm were placed in a zirconia 45 mL container (manufactured by Fritsch), and the sulfide-based inorganic solid electrolyte Li—PS system synthesized above. 0.8 g of glass, 0.04 g of binder (E-1), and 3.6 g of 1,4-dioxane were added as a dispersion medium. Thereafter, this container was set in a planetary ball mill P-7 (manufactured by Fritsch), and stirring was continued for 2 hours at a temperature of 25 ° C. and a rotation speed of 300 rpm. Thereafter, 1.0 g of sufficiently dried molecular sieves 4A as a dehydrating agent was added to prepare a solid electrolyte composition S-2.

Table 1 below summarizes the composition of the solid electrolyte composition.
Here, the solid electrolyte compositions S-1 to S-17 are solid electrolyte compositions of the present invention, and the solid electrolyte compositions T-1 to T-4 are comparative solid electrolyte compositions.

E-1: PVdF-HFP (manufactured by Arkema)
E-2: SBR (manufactured by JSR)
E-3: Acrylic acid-methyl acrylate copolymer prepared by the following method (20/80 molar ratio Mw25000)
In a 100 mL three-necked flask, 1.2 g of acrylic acid (manufactured by Wako Pure Chemical Industries, Ltd.) and 4.2 g of methyl acrylate (manufactured by Wako Pure Chemical Industries, Ltd.) are dissolved in 30 g of MEK (methyl ethyl ketone) and heated to 75 ° C. While replacing with nitrogen. To this was added 0.15 g of azoisobutyronitrile (V-60: trade name, manufactured by Wako Pure Chemical Industries, Ltd.), and the mixture was heated at 75 ° C. for 6 hours in a nitrogen atmosphere. The obtained polymer solution was polymer precipitated with hexane to obtain a white powder.
E-4: Acrylic latex, binder (B-1) described in JP-A-2015-88486
Latex average particle diameter: 500 nm (The average particle diameter was measured by the method described above.)
E-5: Urethane polymer Exemplified compound (44) described in JP-A-2015-88480
LLZ: Li ₇ La ₃ Zr ₂ O ₁₂ (manufactured by Toshima Seisakusho)
Li / P / S: Li—PS system glasses B-1 to B-4 synthesized above: Exemplary compounds (B-1) to (B-4) of dehydrating agents
Boiling point: Boiling point at 760 mmHg

As is apparent from Table 1, the solid electrolyte composition of the present invention shows a good suppression effect on the decrease in ionic conductivity in an accelerated test stored with a high dew point, and the deterioration of the inorganic solid electrolyte due to water is small. It was found that the retention rate of ionic conductivity was high.

-Preparation of composition for positive electrode-
Fifty zirconia beads having a diameter of 3 mm were charged into a zirconia 45 mL container (manufactured by Fritsch), and 6.8 g of a composition having a composition obtained by removing the dehydrating agent from the solid electrolyte composition S-1. To this was added 3.2 g of the positive electrode active material LCO, and then this container was set on a planetary ball mill P-7 (manufactured by Fritsch), and stirring was continued for 10 minutes at a temperature of 25 ° C. and a rotation speed of 100 rpm. Finally, 1.0 g of molecular sieves 4A sufficiently dried as a dehydrating agent (dehydrating agent used in the corresponding solid electrolyte composition S-1) was added to prepare a positive electrode composition P-1.
Since the composition of the positive electrode composition is obtained by combining the composition of the solid electrolyte composition S-1 with the positive electrode active material, in the following Table 2, the composition P for the positive electrode is represented by the solid electrolyte composition S-1 and the positive electrode active material. The composition of -1.

Table 2 below summarizes the composition of the solid electrolyte composition.
Here, the positive electrode compositions P-1 to P-17 are the solid electrolyte compositions of the present invention, and the positive electrode compositions HP-1 to HP-4 are comparative solid electrolyte compositions.

<Notes on the table>
LCO: LiCoO ₂
LMO: LiMn ₂ O ₄
NCA: LiNi _0.85 Co _0.10 Al _0.05 O ₂
NMC: LiNi _1/3 Co _1/3 Mn _1/3 O ₂

-Preparation of composition for negative electrode-
Fifty zirconia beads having a diameter of 3 mm were charged into a zirconia 45 mL container (manufactured by Fritsch), and 6.8 g of a composition having a composition obtained by removing the dehydrating agent from the solid electrolyte composition (S-1) was added. To this, 3.2 g of LTO (Li ₄ Ti ₅ O ₁₂ ) as a negative electrode active material was added, and then this container was set in a planetary ball mill P-7 (manufactured by Fritsch), and the temperature was 25 ° C. and the rotation speed was 100 rpm for 10 minutes. Stirring was continued. Finally, 1.0 g of molecular sieves 4A (a dehydrating agent used in the corresponding solid electrolyte composition (S-1)) sufficiently dried as a dehydrating agent was added to prepare a negative electrode composition N-1.
The composition of the negative electrode composition is the composition of the solid electrolyte composition S-1 combined with the negative electrode active material. The composition of -1.

Table 3 below summarizes the composition of the solid electrolyte composition.
Here, the negative electrode compositions N-1 to N-17 are solid electrolyte compositions of the present invention, and the negative electrode compositions HN-1 to HN-4 are comparative solid electrolyte compositions.

<Notes on the table>
LTO: Li ₄ Ti ₅ O ₁₂

<Production of electrode sheet>
The negative electrode composition shown in Table 3 was filtered through a 50 μm Teflon mesh, then applied onto a stainless steel (SUS) foil as a current collector, and dried at 80 ° C. for 20 minutes to form a negative electrode layer. Furthermore, the solid electrolyte composition shown in Table 1 was applied to the negative electrode layer after filtering through a 50 μm Teflon mesh, and dried at 80 ° C. for 1 hour to form a solid electrolyte layer.
On the other hand, the positive electrode composition shown in Table 2 was filtered through a 50 μm Teflon mesh, then applied onto an aluminum foil as a current collector, and dried at 80 ° C. for 1 hour to form a positive electrode layer.
By laminating these two sheets, an electrode sheet including a negative electrode layer, a solid electrolyte layer, and a positive electrode layer in this order was obtained.
Table 4 below shows combinations of the configurations of the respective layers.

-Manufacture of all-solid-state secondary batteries-
The electrode sheet 17 for an all-solid-state secondary battery produced above was cut into a disk shape having a diameter of 14.5 mm, and, as shown in FIG. 3, put into a stainless steel 2032 type coin case 16 incorporating a spacer and a washer, The all-solid secondary battery 18 having the layer structure shown in FIG. 1 was manufactured by tightening with a torque wrench with a force of 8 Newtons (N).

<Evaluation>
The following evaluation was performed with respect to the all-solid-state secondary batteries of Examples and Comparative Examples produced above. The evaluation results are shown in Table 4 below.
The content of the dehydrating agent remaining in each layer was determined by eluting the solid content of the sheet with toluene and quantifying it using gas chromatography. The remaining amount is shown in mass% per total solid content in the sheet.

-Battery voltage-
The battery voltage of the all-solid-state secondary battery produced above was measured with a charge / discharge evaluation device “TOSCAT-3000 (trade name)” manufactured by Toyo System Co., Ltd.
Charging is performed at a current density of 2 A / m ² until the battery voltage reaches 4.2 V. After reaching 4.2 V, the constant voltage at 4.2 V is obtained until the current density becomes less than 0.2 A / m ^2. Charging was performed. Discharging was performed at a current density of 2 A / m ² until the battery voltage reached 3.0V. This was repeated three times as one cycle, and the battery voltage after 5 mAh / g discharge in the third cycle was read.
Evaluation was made according to the following evaluation criteria. Ranks A to C are acceptable levels.

<Evaluation criteria>
A: The rate of decrease in the voltage of the all-solid-state secondary battery after storage for 2 weeks for a fresh product is 10% or less B: The rate of decrease in the voltage of the all-solid-state secondary battery after storage for 2 weeks for a fresh product exceeds 10% and is 30 % Or less C: The decrease rate of the voltage of the all-solid-state secondary battery after storage for 2 weeks with respect to the fresh product exceeds 30% and 50% or less D: The decrease rate of the voltage of the all-solid-state secondary battery after storage with 2 weeks for the fresh product Exceeds 50% and is 70% or less E: The battery is not driven.

Fresh product: Storage condition of all-solid secondary battery composition prepared within 24 hours after preparation of each composition above: Storage condition of all-solid secondary battery with dew point of -60 ° C or less under argon atmosphere: Argon atmosphere Below dew point -60 ℃ or less

As can be seen from Table 4 above, the all-solid-state secondary battery produced from the solid electrolyte composition not satisfying the provisions of the present invention failed in battery voltage.
On the other hand, the all-solid-state secondary battery in which at least one layer was produced from the solid electrolyte composition of the present invention was excellent in battery voltage. From this result, it can be seen that in the all-solid-state secondary battery produced from the solid electrolyte composition of the present invention, the deterioration of the inorganic solid electrolyte due to moisture absorption is suppressed.

While this invention has been described in conjunction with its embodiments, we do not intend to limit our invention in any detail of the description unless otherwise specified and are contrary to the spirit and scope of the invention as set forth in the appended claims. I think it should be interpreted widely.

This application claims priority based on Japanese Patent Application No. 2016-1000061 filed in Japan on May 19, 2016, which is hereby incorporated herein by reference. Capture as part.

DESCRIPTION OF SYMBOLS 1 Negative electrode collector 2 Negative electrode active material layer 3 Solid electrolyte layer 4 Positive electrode active material layer 5 Positive electrode collector 6 Working part 10 All-solid-state secondary battery 11 Upper support plate 12 Lower support plate 13 Coin-shaped jig 14 Coin case 15 Solid Electrolyte-containing sheet S Screw 16 2032 type coin case 17 Electrode sheet 18 for all-solid-state secondary battery 18 All-solid-state secondary battery

Claims

A solid electrolyte composition containing an inorganic solid electrolyte (A) having conductivity of metal ions belonging to Group 1 or Group 2 of the periodic table, a dehydrating agent (B), and a dispersion medium (C).
The solid electrolyte composition according to claim 1, wherein the inorganic solid electrolyte (A) is a sulfide-based inorganic solid electrolyte.
The solid electrolyte composition according to claim 1 or 2, wherein the dehydrating agent (B) is an organic compound having a partial structure in which two or more oxygen atoms are bonded to the same carbon atom or the same sulfur atom.
The dehydrating agent (B) is an organic compound that reacts with water to form a product having a partial structure represented by any one of the following general formulas (1) to (3). 2. The solid electrolyte composition according to item 1.

In the general formulas (1) to (3), R 1 , R 2 , R 31 and R 32 each independently represent a hydrogen atom, an alkyl group or an aryl group. X 1 , X 2 , X 31 and X 32 each independently represent a single bond, an oxygen atom, a sulfur atom or —N (R 3 ) —. R 3 represents a hydrogen atom, an alkyl group or an aryl group. Y 1 represents a carbon atom or a sulfur atom. Y 2 represents a sulfur atom. Y 3 represents a phosphorus atom. * Indicates a linking site in the product.
The solid electrolyte composition according to any one of claims 1 to 4, wherein the dehydrating agent (B) is at least one selected from the group consisting of acid anhydrides, acid halides, acetals, and orthoesters.
The solid electrolyte composition according to any one of claims 1 to 5, wherein the dehydrating agent (B) is an organic compound having a fluorine atom.
The solid electrolyte composition according to any one of claims 1 to 6, wherein a content of the dehydrating agent (B) is 1% by mass or more and 50% by mass or less in a total solid content of the solid electrolyte composition.
The solid electrolyte composition according to any one of claims 1 to 7, wherein the dehydrating agent (B) has a molecular weight of 300 or less or a boiling point at 760 mmHg of 300 ° C or less.
9. The dehydrating agent (B) is a liquid at 25 ° C., and the mass ratio (B) / (C) to the dispersion medium (C) is 1/99 to 99/1. The solid electrolyte composition described in 1.
The solid electrolyte composition according to any one of claims 1 to 9, comprising an active material (D).
The solid electrolyte composition according to any one of claims 1 to 10, comprising a binder (E).
The solid electrolyte composition according to claim 11, wherein the binder (E) is at least one selected from the group consisting of an acrylic resin, a polyurethane resin, a polyurea resin, a polyimide resin, a fluorine-containing resin, and a hydrocarbon-based thermoplastic resin. object.
The solid electrolyte composition according to claim 11 or 12, wherein the binder (E) has a polar group.
A solid electrolyte-containing sheet containing an inorganic solid electrolyte (A) having conductivity of ions of metals belonging to Group 1 or Group 2 of the periodic table and a dehydrating agent (B).
The method for producing a solid electrolyte-containing sheet according to claim 14, wherein the dehydrating agent (B) is contained in a total solid content of 5% by mass or less.
Filtering the solid electrolyte composition containing the inorganic solid electrolyte (A), the dehydrating agent (B), and the dispersion medium (C);
Applying the filtrate obtained in the above step onto a substrate;
The manufacturing method of the solid electrolyte containing sheet | seat which has the process of heat-drying.
An all-solid secondary battery comprising a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer,
The all-solid-state secondary battery whose at least 1 layer of the said positive electrode active material layer, the said negative electrode active material layer, and the said solid electrolyte layer is a solid electrolyte containing sheet | seat of Claim 14.
A method for producing an all-solid secondary battery, wherein an all-solid secondary battery is produced through the production method according to claim 15.