WO2019203334A1

WO2019203334A1 - Solid electrolyte composition, all-solid secondary battery sheet, all-solid secondary battery, and method of manufacturing all-solid secondary battery sheet or all-solid secondary battery

Info

Publication number: WO2019203334A1
Application number: PCT/JP2019/016723
Authority: WO
Inventors: 陽串田; 宏顕望月; 智則三村; 安田　浩司
Original assignee: 富士フイルム株式会社
Priority date: 2018-04-20
Filing date: 2019-04-18
Publication date: 2019-10-24
Also published as: JP6982682B2; JPWO2019203334A1

Abstract

Provided are: a solid electrolyte composition comprising an inorganic solid electrolyte conductive to ions of a metal of Group I or Group II of the periodic table, a binder, and a disperse medium, wherein the binder comprises a polymer which contains a constituent component expressed by the general formula (1), and a constituent component derived from a macromonomer having a number average molecular weight of not less than 2,000; an all-solid secondary battery sheet and an all-solid secondary battery using the composition; and a method of manufacturing each of the all-solid secondary battery sheet and the all-solid secondary battery. In the formula, α represents a ring; L represents -O-, -NR⁴-, or -S-; R¹ to R⁴ represents a hydrogen atom or a monovalent substitution group; and * represents a binding portion of the constituent components.

Description

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

The present invention relates to a solid electrolyte composition, an all-solid secondary battery sheet, an all-solid secondary battery, and an all-solid secondary battery sheet or an all-solid secondary battery manufacturing method.

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 can be charged and discharged 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 and overdischarge, resulting in ignition, and further improvement in reliability and safety is required.
Under such circumstances, an all-solid secondary battery using an inorganic solid electrolyte instead of an organic electrolyte has been attracting attention. The all-solid-state secondary battery is composed of a solid negative electrode, electrolyte, and positive electrode, which can greatly improve safety and reliability, which are the problems of batteries using organic electrolytes, and can also extend the service life. It will be. Furthermore, the all-solid-state secondary battery can have a structure in which an electrode 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 or a large storage battery is expected.

In such all-solid secondary batteries, battery performance is improved by increasing the binding between solid particles such as inorganic solid electrolytes. In order to enhance the binding property between solid particles, the constituent layer of the battery of any one of the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer is a material containing an inorganic solid electrolyte and a binder (binder). It is proposed to form in. As such a material, for example, Patent Document 1 describes a solid electrolyte composition containing non-spherical polymer particles having a specific functional group, a dispersion medium, and an inorganic solid electrolyte. Patent Document 2 describes a solid electrolyte composition containing an inorganic solid electrolyte, a binder having specific constituent components composed of core-shell particles having a core portion and a shell portion, and a dispersion medium. In

Patent Documents

1 and 2, by using these solid electrolyte compositions as materials constituting the constituent layers, it is possible to suppress a decrease in ionic conductivity without depending on pressure in the obtained all-solid-state secondary battery. It is said that good binding properties can be realized.

JP 2015-167126 A Japanese Patent No. 6101223

For the practical application of all-solid-state secondary batteries, improvement of battery performance such as ion conductivity is being studied, and studies for mass production of all-solid-state secondary batteries are also being conducted. When manufacturing an all-solid-state secondary battery using a solid electrolyte composition (slurry) containing a dispersion medium, the constituent layer is formed by evaporating or volatilizing the dispersion medium by heating and drying after applying the slurry. However, if the cohesion between the solid particles is insufficient, damage (for example, cracks) will occur in the formed component layer due to volume change when the dispersion medium evaporates and dissipates due to drying. Therefore, there is a problem that the battery performance is lowered and the battery life is shortened. In order to solve this problem, it is necessary to further improve the binding property between the solid particles and to impart the property that the constituent layer after drying is less likely to be damaged.

The present invention can be used as a material for constituting the all-solid-state secondary battery sheet or the constituent layer of the all-solid-state secondary battery, and by heating and drying in the manufacturing process of the all-solid-state secondary battery sheet or all-solid-state secondary battery. Another object of the present invention is to provide a solid electrolyte composition capable of preventing damage to the solid electrolyte layer and / or the electrode active material layer. In addition, the present invention is excellent in a sheet for an all-solid secondary battery or an all-solid-state secondary battery obtained by using it as a material constituting the constituent layer of the all-solid-state secondary battery sheet or the all-solid-state secondary battery. It is an object to provide a solid electrolyte composition capable of realizing ionic conductivity. Furthermore, the present invention provides an all-solid-state secondary battery sheet and an all-solid-state secondary battery, and an all-solid-state secondary battery sheet and an all-solid-state secondary battery manufacturing method using this solid electrolyte composition. The task is to do.

As a result of various investigations, the present inventors have found that a binder containing a specific component having a ring in the side chain and a component derived from a macromonomer having a number average molecular weight of 2,000 or more, and a specific inorganic solid By using a solid electrolyte composition in which an electrolyte is dispersed in a dispersion medium as a constituent material of a constituent layer of an all-solid secondary battery sheet and an all-solid secondary battery, solid particles can be firmly bound, As a result, it was found that the solid electrolyte layer and / or the electrode active material layer are hardly damaged, and as a result, excellent battery performance can be imparted to the all-solid secondary battery. 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>
A polymer comprising an inorganic solid electrolyte having ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, a binder, and a dispersion medium and constituting the binder is represented by the following general formula (1). And a solid electrolyte composition containing a constituent derived from a macromonomer having a number average molecular weight of 2,000 or more.

In the formula, α represents a ring. L represents —O—, —NR ⁴ — or —S—. R ¹ to R ⁴ represent a hydrogen atom or a monovalent substituent. * Indicates a connecting part of the constituent components.

<2>
The solid electrolyte composition according to <1>, wherein the ring α has a single ring or a bridged ring structure.
<3>
The solid electrolyte composition according to <1> or <2>, wherein the ring α is represented by any one of the following general formulas (I) to (III).

In the formula, Y and Z represent —CR ⁵ R ⁶ —, —O—, —NR ⁵ — or —S—. L ¹ and L ² represent a divalent linking group. R ⁵ and R ⁶ represent a hydrogen atom or a monovalent substituent. A wavy line indicates a coupling portion with L.

<4>
<1> to <3>, wherein the content of the constituent represented by the general formula (1) is 0.01 to 50% by mass in the constituents of the polymer constituting the binder (B). The solid electrolyte composition as described in any one.
<5>
The solid electrolyte composition according to any one of <1> to <4>, wherein L represents —O— or —NR ⁴ —.
<6>
<3> The solid electrolyte composition according to <3>, wherein Y represents —CR ⁵ R ⁶ — in the general formula (I), and Z represents —CR ⁵ R ⁶ — in the general formula (II).
<7>
The solid electrolyte composition according to <3>, wherein the ring α is represented by the general formula (III).
<8>
The solid electrolyte composition according to any one of <1> to <7>, wherein the content of the constituent component derived from the macromonomer is 10 to 50% by mass in the constituent components of the polymer constituting the binder. object.
<9>
The solid electrolyte composition according to any one of <1> to <8>, wherein the solubility parameter of the dispersion medium is 21 MPa ^1/2 or less.
<10>
The solid electrolyte composition according to any one of <1> to <9>, containing a lithium salt.
<11>
The solid electrolyte composition according to any one of <1> to <10>, which contains an active material.
<12>
The solid electrolyte composition according to any one of <1> to <11>, which contains a conductive additive.
<13>
The solid electrolyte composition according to any one of <1> to <12>, wherein the inorganic solid electrolyte is a sulfide-based inorganic solid electrolyte.

<14>
<1> to <13> A sheet for an all-solid-state secondary battery having a layer formed of the solid electrolyte composition according to any one of <1> to <13>.
<15>
An all solid state secondary battery comprising a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order,
All solids in which at least one of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer is a layer composed of the solid electrolyte composition according to any one of <1> to <13> Secondary battery.
<16>
<1>-<13> The manufacturing method of the sheet | seat for all-solid-state secondary batteries which forms the solid electrolyte composition as described in any one of <13>.
<17>
The manufacturing method of the all-solid-state secondary battery which manufactures the all-solid-state secondary battery using the manufacturing method as described in <16>.

The solid electrolyte composition of the present invention can be obtained by using the all-solid-state secondary battery sheet or the all-solid-state secondary battery sheet by using it as a material constituting the constituent layer of the all-solid-state secondary battery sheet or the all-solid-state secondary battery. Even at the time of heating and drying treatment in the production process, the solid electrolyte layer and / or the electrode active material layer can be hardly damaged. Moreover, the solid electrolyte composition of the present invention is an all-solid-state secondary battery sheet or all-solid-state secondary battery obtained by using it as a material constituting the constituent layer of the all-solid-state secondary battery sheet or the all-solid-state secondary battery. Excellent ionic conductivity can be realized in the battery. The sheet for an all-solid-state secondary battery of the present invention exhibits excellent ionic conductivity because the solid electrolyte layer and / or the electrode active material layer are hardly damaged even during heating and drying in the production process. The all solid state secondary battery of the present invention comprises the all solid state secondary battery sheet exhibiting excellent ion conductivity. Moreover, the manufacturing method of the all-solid-state secondary battery sheet | seat and all-solid-state secondary battery of this invention manufactures the all-solid-state secondary battery sheet | seat and all-solid-state secondary battery of this invention which show the said outstanding characteristic, respectively. Can do.

It is a longitudinal cross-sectional view which shows typically the all-solid-state secondary battery which concerns on preferable embodiment of this invention. It is a longitudinal cross-sectional view which shows typically the all-solid-state secondary battery (coin battery) produced in the Example.

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, the indication of a compound (for example, when referring to a compound with a suffix) is used to mean that the compound itself, its salt, and its ion are included. In addition, it is meant to include derivatives in which a part thereof is changed, such as introduction of a substituent, within a range where a desired effect is exhibited.
In the present specification, a substituent that does not specify substitution or non-substitution (the same applies to a linking group) means that the group may have an appropriate substituent. This is also synonymous for compounds that do not specify substitution or non-substitution. Preferred substituents include the following substituent Z.
Moreover, in this specification, when it describes only as a YYY group, the YYY group may have a substituent further.
In the present specification, when there are a plurality of substituents, linking groups, etc. (hereinafter referred to as substituents, etc.) indicated by specific symbols, or when a plurality of substituents etc. are specified simultaneously or alternatively, It means that a substituent etc. may mutually be same or different. In addition, even when not specifically stated, when a plurality of substituents and the like are adjacent to each other, they may be connected to each other or condensed to form a ring.

[Solid electrolyte composition]
The solid electrolyte composition of the present invention includes an inorganic solid electrolyte having ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, a binder, and a dispersion medium. The polymer which comprises the said binder contains the structural component shown by postscript general formula (1), and the structural component derived from a macromonomer with a number average molecular weight of 2,000 or more.

In the solid electrolyte composition of the present invention, the aspect (mixing aspect) containing the inorganic solid electrolyte, the binder, and the dispersion medium is not particularly limited, but is a slurry in which the inorganic solid electrolyte and the binder are dispersed in the dispersion medium. Is preferred.
Even when the solid electrolyte composition of the present invention is made into a slurry, solid particles such as an inorganic solid electrolyte, an active material used in combination as desired, and a conductive additive can be well dispersed.

The reason why the solid electrolyte composition of the present invention exhibits the above-mentioned effects is not yet clear, but is estimated as follows.
The polymer constituting the binder used in the present invention contains a component derived from a macromonomer having a number average molecular weight of 2,000 or more, and further has a ring in the side chain and is represented by the general formula (1) By having the component, the aggregation of the binder in the solid electrolyte composition is highly suppressed, and the solid electrolyte composition of the present invention is considered to maintain high dispersibility. Furthermore, it is considered that the polymer constituting the binder has such a structure, so that the fluidity of the binder after the solid components such as the inorganic solid electrolyte are bound to each other is suppressed and high interfacial adhesion is exhibited. . Combined with these actions, the solid electrolyte composition of the present invention is used as a material for constituting the all-solid-state secondary battery sheet or the constituent layer of the all-solid-state secondary battery, thereby increasing the binding between the solid particles. It is thought that the above-mentioned effects are produced.

The solid electrolyte composition of the present invention is not particularly limited, but the moisture content (also referred to as water content) is preferably 500 ppm or less, more preferably 200 ppm or less, and further preferably 100 ppm or less. It is preferably 50 ppm or less. When the water content of the solid electrolyte composition is small, deterioration of the inorganic solid electrolyte can be suppressed. The water content indicates the amount of water contained in the solid electrolyte composition (mass ratio with respect to the solid electrolyte composition). Specifically, the water content is filtered through a 0.02 μm membrane filter, and Karl Fischer titration is used. The measured value.

Hereinafter, components contained in the solid electrolyte composition of the present invention and components that can be contained will be described.

<Inorganic solid electrolyte>
The solid electrolyte composition of the present invention contains an inorganic solid electrolyte.
In the present invention, 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 an electrolyte or an inorganic electrolyte salt (such as LiPF ₆ , LiBF ₄ , lithium bis (fluorosulfonyl) imide (LiFSI), LiCl, etc.) in which cations and anions are dissociated or liberated in the polymer. Is done. 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. When the all solid state secondary battery of the present invention is a lithium ion battery, the inorganic solid electrolyte preferably has lithium ion ionic conductivity.
As the inorganic solid electrolyte, a solid electrolyte material usually used for an all-solid secondary battery 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, a sulfide-based inorganic solid electrolyte is preferably used from the viewpoint that a better interface can be formed between the active material and the inorganic solid electrolyte.

(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.

Examples of the sulfide-based inorganic solid electrolyte include a lithium ion conductive inorganic solid electrolyte that satisfies the composition represented by the following formula (1).

L _a1 M _b1 P _c1 S _d1 A _e1 (1)

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 preferably 1 to 9, and more preferably 1.5 to 7.5. b1 is preferably 0 to 3, and more preferably 0 to 1. d1 is preferably 2.5 to 10, and more preferably 3.0 to 8.5. e1 is preferably from 0 to 5, and more preferably from 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 the 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 ceramics 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 Those having electronic insulating properties are preferred.
The oxide-based inorganic solid electrolyte preferably has an ionic conductivity of 1 × 10 ⁻⁶ S / cm or more, more preferably 5 × 10 ⁻⁶ S / cm or more, and 1 × 10 ⁻⁵ S. / Cm or more is particularly preferable. The upper limit is not particularly limited, but is practically 1 × 10 ⁻¹ S / cm or less.

As a specific compound example, for example, Li _xa La _ya TiO ₃ [xa satisfies 0.3 ≦ xa ≦ 0.7, and ya satisfies 0.3 ≦ ya ≦ 0.7. (LLT); Li _xb La _yb Zr _zb M ^bb _mb _Onb (M ^bb is one or more elements selected from Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In and Sn) Xb satisfies 5 ≦ xb ≦ 10, 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 one or more elements selected from C, S, Al, Si, Ga, Ge, In and Sn. Xc is 0 ≦ xc ≦ 5 Yc satisfies 0 ≦ yc ≦ 1, zc satisfies 0 ≦ zc ≦ 1, and nc satisfies 0 ≦ nc ≦ 6); Li _xd (Al, Ga) _yd (Ti, Ge) _zd Si _ad P _md _Ond (xd satisfies 1 ≦ xd ≦ 3, yd Satisfies 0 ≦ yd ≦ 1, zd satisfies 0 ≦ zd ≦ 2, ad satisfies 0 ≦ ad ≦ 1, md satisfies 1 ≦ md ≦ 7, and nd satisfies 3 ≦ nd ≦ 13.) Li _(3-2xe) M ^ee _xe D ^ee O (xe represents a number of 0 to 0.1, M ^ee represents a divalent metal atom, D ^ee represents a halogen atom or two or more types of halogen atoms; represent a combination _{_{_{of);. Li xf Si yf O}}} zf (xf satisfies 1 ≦ xf ≦ 5, yf satisfies 0 <yf ≦ 3, zf satisfies _{1 ≦ zf ≦ 10);.} Li xg S yg O _zg (xg satisfies 1 ≦ xg ≦ 3, yg satisfies 0 <yg ≦ 2, and zg satisfies 1 ≦ zg ≦ 10); Li ₃ BO ₃ ; 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); LISICON Li 3.5} Zn 0.25 GeO with (Lithium super ionic conductor) type crystal structure ₄ ; La _0.55 Li _0.35 TiO ₃ having a perovskite-type crystal structure; LiTi ₂ P ₃ O ₁₂ having a NASICON (Natrium super ionic conductor) type crystal structure; Li _{1 + xh + yh} (Al, Ge) _xh (Ti, Ge) _2-xh Si _yh P _3-yh O ₁₂ (xh satisfies 0 ≦ xh ≦ 1 and yh satisfies 0 ≦ yh ≦ 1) And Li ₇ La ₃ Zr ₂ O ₁₂ (LLZ) having a garnet-type crystal structure.
Phosphorus compounds containing Li, P and O are also desirable. For example, lithium phosphate (Li ₃ PO ₄ ); LiPON obtained by substituting a part of oxygen of lithium phosphate with nitrogen; LiPOD ¹ (D ¹ is preferably Ti, V, Cr, Mn, Fe, Co, Ni, And at least one element selected from Cu, Zr, Nb, Mo, Ru, Ag, Ta, W, Pt, and Au.
Furthermore, LiA ¹ ON (A ¹ is one or more elements selected from Si, B, Ge, Al, C, and Ga) can be preferably used.

The inorganic solid electrolyte is preferably a particle. In this case, 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. The volume average particle size of the inorganic solid electrolyte is measured by the following procedure. The inorganic solid electrolyte particles are prepared by diluting a 1% by weight dispersion in water (heptane in the case of a substance unstable to water) in a 20 mL sample bottle. 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 apparatus LA-920 (trade name, manufactured by HORIBA), data acquisition was performed 50 times using a measurement quartz cell at a temperature of 25 ° C. Obtain the volume average particle size. For other detailed conditions, refer to the description of JIS Z 8828: 2013 “Particle Size Analysis—Dynamic Light Scattering Method” as necessary. Five samples are prepared for each level, and the average value is adopted.

An inorganic solid electrolyte may be used individually by 1 type, or may be used in combination of 2 or more type.
When forming a solid electrolyte layer, the mass (mg) (weight per unit area) of the inorganic solid electrolyte per unit area (cm ² ) of the solid electrolyte layer is not particularly limited. It can be determined as appropriate according to the designed battery capacity, for example, 1 to 100 mg / cm ² .
However, when the solid electrolyte composition contains an active material to be described later, the weight of the inorganic solid electrolyte is preferably the total amount of the active material and the inorganic solid electrolyte in the above range.

The content of the inorganic solid electrolyte in the solid electrolyte composition is preferably 5% by mass or more at a solid content of 100% by mass in terms of dispersion stability, reduction of interface resistance, and binding properties, and 70% by mass. % Or more is more preferable, and 90% by mass or more is particularly preferable. As an upper limit, it is preferable that it is 99.9 mass% or less from the same viewpoint, It is more preferable that it is 99.5 mass% or less, It is especially preferable that it is 99 mass% or less.
However, when the solid electrolyte composition contains an active material to be described later, the total content of the active material and the inorganic solid electrolyte is preferably in the above range as the content of the inorganic solid electrolyte in the solid electrolyte composition.
In this specification, solid content (solid component) means the component which does not lose | disappear by volatilizing or evaporating, when a solid electrolyte composition is dried at 170 degreeC under a nitrogen atmosphere at 170 degreeC for 1 hour. Typically, it refers to components other than the dispersion medium described below.

<Binder>
The solid electrolyte composition of the present invention contains a binder, and the polymer constituting the binder is derived from a constituent represented by the following general formula (1) and a macromonomer having a number average molecular weight of 2,000 or more. Containing ingredients.

In the formula, α represents a ring. L represents —O—, —NR ⁴ — or —S—. R ¹ to R ⁴ represent a hydrogen atom or a monovalent substituent. * Indicates a connecting part.
R ¹ , R ³ and R ⁴ preferably represent a hydrogen atom, and R ² preferably represents a substituent.

In the present invention, L can resonate with the carbonyl group, so that the mobility of the main chain can be lowered and the aggregation of the binder can be suppressed. In addition, since it is desirable that the hydrogen bond forming ability is low in order to suppress the cohesive force, L preferably represents —O— or —NR ⁴ —.

Specific examples of the substituent include the substituent T described later. Of these, an alkyl group is preferable, and a methyl group is more preferable.

Ring α is preferably a single ring, a condensed ring, a bridged ring, a spiro ring, or a ring formed by bonding at least two of them.
Ring α may be either an aliphatic ring or an aromatic ring, and may be a hydrocarbon ring or a heterocyclic ring. Examples of the hetero atom contained in the heterocycle include an oxygen atom, a nitrogen atom, and a sulfur atom.

The monocycle is preferably a 3- to 15-membered ring, more preferably a 5- to 10-membered ring, and even more preferably a 6-membered ring. The number of carbon atoms constituting the monocyclic ring is preferably 3-20, more preferably 5-10, and even more preferably 6.
The condensed ring is preferably a ring obtained by condensing the single ring.
The bridged ring is preferably a 2-5 ring system, more preferably a 2-4 ring system, and even more preferably a 2 or 3 ring system. The number of carbon atoms constituting the bridge ring is preferably 4 to 20, more preferably 5 to 15, and still more preferably 6 to 12.
The ring constituting the spiro ring is preferably a 3- to 15-membered ring, more preferably a 4- to 10-membered ring, and even more preferably a 5- to 8-membered ring. The number of carbon atoms constituting the spiro ring is preferably 6 to 30, more preferably 7 to 20, and still more preferably 8 to 15.

In the present invention, the solid electrolyte layer and / or the electrode active material layer is less likely to be damaged by heat drying in the manufacturing process of the all-solid-state secondary battery sheet or the all-solid-state secondary battery, and the ionic conductivity is further improved. Therefore, the ring α is preferably a single ring or a bridged ring, and more preferably a bridged ring.

In the present invention, since the cohesive force can be suppressed by having a rigid functional group in the side chain of the polymer constituting the binder, the ring α is represented by any one of the following general formulas (I) to (III). It is preferable that it is a ring. Further, because of the particularly rigid structure, it is more preferable that the ring α is a ring represented by the following general formula (III).

Y preferably represents —CR ⁵ R ⁶ —, and R ⁵ and R ⁶ preferably represent a hydrogen atom. Z preferably represents —CR ⁵ R ⁶ — or —O—, and more preferably —CR ⁵ R ⁶ —. This is because that the ring-constituting atom of the ring α is a carbon atom, dipole interaction can be suppressed and aggregation of binders can be suppressed.
Specific examples of the substituent represented by R ⁵ and R ⁶ include the substituent T described later.

Examples of the divalent linking group represented by L ¹ include an alkylene group. The alkylene group preferably has 1 to 15 carbon atoms, more preferably 2 to 10 carbon atoms, and still more preferably 4 carbon atoms.

Examples of the divalent linking group represented by L ² include an alkylene group. The alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and still more preferably 2 carbon atoms.

In the present invention, when L represents —NR ⁴ —, the ring α is preferably represented by the general formula (I). When L represents O, the ring α is preferably represented by the general formula (II) or (III), and more preferably represented by the general formula (III).

Below, the monomer and macromonomer for introduce | transducing the structural component represented by General formula (1) are demonstrated. Each monomer demonstrated below may be used individually by 1 type, and may be used in combination of 2 or more type.
For the synthesis of the polymer constituting the binder, at least a monomer represented by the following general formula (1a) and a macromonomer having a number average molecular weight of 2,000 or more are used.

(Monomer represented by the general formula (1a))

Wherein, alpha, L, and ^R 1 ~ ^{R 3} are, alpha in the general formula (1) has the same meaning as L, and ^R 1 ~ ^{R 3,} and the preferred range is also the same.

Specific examples of the monomer represented by the general formula (1a) are described below, but the present invention is not limited to these.

(Macromonomer with a number average molecular weight of 2,000 or more)
The number average molecular weight of the macromonomer may be 2,000 or more, but is preferably 4,000 or more, and preferably 6,000 or more in terms of the binding property of the solid particles and further the dispersibility of the solid particles. More preferably, it is more preferably 8000 or more. It does not restrict | limit especially as an upper limit, It is preferable that it is 500,000 or less, It is more preferable that it is 100,000 or less, It is especially preferable that it is 30,000 or less.

The macromonomer is preferably a compound having an ethylenically unsaturated bond at the end or side chain of the molecular structure. For example, a styrene compound, vinyl naphthalene, vinyl carbazole, (meth) acrylic acid, (meth) acrylic acid ester compound, (meta ) Number average molecular weight of 2,000 or more among compounds having a structure derived from at least one of acrylamide compound, (meth) acrylonitrile compound, allyl compound, vinyl ether compound, vinyl ester compound, and dialkyl itaconate compound Is mentioned. The number of ethylenically unsaturated bonds (addition polymerizable unsaturated bonds) possessed by the macromonomer per molecule is one or more (preferably 1 to 4), and more preferably one.

The macromonomer is preferably a monomer represented by the following general formula (2).

In the formula, R ⁷ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. The alkyl group preferably has 1 to 3 carbon atoms, more preferably 1. R ⁷ is preferably a hydrogen atom or methyl.

In formula, W shows a single bond or a coupling group, and a coupling group is preferable.
The linking group that can be taken as W is not particularly limited, but is an alkylene group having 1 to 30 carbon atoms, a cycloalkylene group having 3 to 12 carbon atoms, an arylene group having 6 to 24 carbon atoms, or a heteroarylene group having 3 to 12 carbon atoms. Group), ether group (—O—), sulfide group (—S—), phosphinidene group (—PR—: R is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms), silylene group (—SiR ^S1 R ^S2 — : ^R ^{S1, R S2} is hydrogen or an alkyl group having 1 to 6 carbon atoms), a carbonyl group, an imino group ^(-NR ^N -: ^R N represents a hydrogen atom, an alkyl group or a C 6 -C 1 to 6 carbon atoms 10 aryl groups) or a linking group obtained by combining two or more (preferably 2 to 10) thereof. Among them, an alkylene group having 1 to 30 carbon atoms, an arylene group having 6 to 24 carbon atoms, an ether group, a carbonyl group, a sulfide group, or a linking group obtained by combining two or more (preferably 2 to 10) thereof. It is more preferable.

In the general formula (2), P ¹ represents a polymer chain, and the connection site with W is not particularly limited, and may be the end of the polymer chain or a side chain. The polymer chain that can be taken as P ¹ is not particularly limited, and a polymer chain made of a normal polymer can be applied. Examples of such a polymer chain include a chain made of (meth) acrylic polymer, polyether, polysiloxane or polyester, or a chain obtained by combining two (preferably two or three) of these chains. . Among these, a chain containing a (meth) acrylic polymer is preferable, and a chain made of a (meth) acrylic polymer is more preferable. In the combined chain, the combination of the chains is not particularly limited, and is appropriately determined.

The chain made of (meth) acrylic polymer, polyether, polysiloxane and polyester is not particularly limited as long as it is a normal chain made of (meth) acrylic resin, polyether resin, polysiloxane and polyester resin.
For example, the (meth) acrylic polymer may be a heavy polymer containing a constituent derived from a polymerizable compound selected from (meth) acrylic acid, (meth) acrylic ester compounds, (meth) acrylamide compounds and (meth) acrylonitrile compounds. A polymer is preferable, and a polymer containing a constituent derived from a polymerizable compound selected from (meth) acrylic acid, a (meth) acrylic acid ester compound and a (meth) acrylonitrile compound is more preferable. In particular, among (meth) acrylic acid ester compounds, a polymer containing a constituent derived from a long-chain alkyl ester of (meth) acrylic acid is preferable. The carbon number of the long chain alkyl group is, for example, preferably 4 or more, more preferably 4 to 24, and still more preferably 8 to 20. The (meth) acrylic polymer may include a component derived from the above-described polymerizable compound having an ethylenically unsaturated bond, such as a styrene compound or a cyclic olefin compound.

Examples of the polyether include polyalkylene ether and polyarylene ether. The alkylene group of the polyalkylene ether preferably has 1 to 10 carbon atoms, more preferably 2 to 6 carbon atoms, and particularly preferably 2 to 4 carbon atoms. The arylene group of the polyarylene ether preferably has 6 to 22 carbon atoms, and more preferably 6 to 10 carbon atoms. The alkylene group and arylene group in the polyether chain may be the same or different. The terminal in the polyether chain is a hydrogen atom or a substituent, and examples of this substituent include an alkyl group (preferably having a carbon number of 1 to 20).

Examples of the polysiloxane include a chain having a repeating unit represented by —O—Si (R ^S ₂ ) —. In the above repeating unit, R ^S represents a hydrogen atom or a substituent, and the substituent is not particularly limited, and is a hydroxy group or an alkyl group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and 1 to 3 carbon atoms). Is particularly preferred), an alkenyl group (preferably 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms, particularly preferably 2 or 3), an alkoxy group (preferably 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms). 1 to 6 is more preferable, and 1 to 3 is particularly preferable.), An aryl group (preferably 6 to 22 carbon atoms, more preferably 6 to 14 carbon atoms, and particularly preferably 6 to 10 carbon atoms), an aryloxy group (carbon number). 6 to 22, preferably 6 to 14, more preferably 6 to 10, and an aralkyl group (preferably 7 to 23 carbon atoms, more preferably 7 to 15 carbon atoms, and particularly preferably 7 to 11 carbon atoms). ). Among these, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a phenyl group is more preferable, and an alkyl group having 1 to 3 carbon atoms is more preferable. The group located at the terminal of the polysiloxane is not particularly limited, but is an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 6 carbon atoms, and preferably 1 to 3 carbon atoms), alkoxy group (having 1 to 20 carbon atoms). Preferably, 1 to 6 is more preferable, and 1 to 3 is particularly preferable.), An aryl group (preferably having 6 to 26 carbon atoms, more preferably 6 to 10), a heterocyclic group (preferably at least one oxygen atom) A heterocyclic group having a sulfur atom or a nitrogen atom and having 2 to 20 carbon atoms, preferably a 5-membered ring or a 6-membered ring). The polysiloxane may be linear or branched.

The polyester is not particularly limited as long as it is composed of a polycondensate of a polyvalent carboxylic acid and a polyhydric alcohol. Examples of the polyvalent carboxylic acid and the polyhydric alcohol include those usually used, and examples thereof include an aliphatic or aromatic polyvalent carboxylic acid and an aliphatic or aromatic polyhydric alcohol. The valence of the polyvalent carboxylic acid and polyhydric alcohol may be 2 or more, and is usually 2 to 4.

The macromonomer further includes a monomer having a polymer chain selected from the group consisting of (meth) acrylic polymers, polyethers, polysiloxanes, polyesters, and combinations thereof, and an ethylenically unsaturated bond bonded to the polymer chain. preferable. The polymer chain which this macromonomer has is synonymous with the polymer chain which can preferably take the polymer chain P ¹ in the general formula (2), and the preferable one is also the same. Examples of the ethylenically unsaturated bond include a vinyl group and a (meth) acryloyl group, and a (meth) acryloyl group is preferable. The polymer chain and the ethylenically unsaturated bond may be bonded directly (without via a linking group) or may be bonded via a linking group. Examples of the linking group in this case include a linking group that can be taken as W in the general formula (2).

The SP value of the macromonomer is not particularly limited, and is preferably 21 or less, for example, and more preferably 20 or less. As a lower limit, it is practical that it is 15 or more.

Polymerization degree of the polymer chains with the macromonomer (corresponding to the polymer chain P ¹ in the general formula (2)) is, if the number average molecular weight of the macromonomer is more than 2,000 is not particularly limited, 5 It is preferably ˜5,000, more preferably 10 to 300.

In the present invention, the content of the component represented by the general formula (1) is preferably 0.01 to 50% by mass, preferably 0.1 to 40% by mass in the components of the polymer constituting the binder. % Is more preferable, and 1 to 30% by mass is further preferable. When the content of the component represented by the general formula (1) is within the above range, the solid electrolyte layer can be obtained by heating and drying processes in the manufacturing process of the all-solid-state secondary battery sheet or all-solid-state secondary battery. In addition, damage to the electrode active material layer is less likely to occur, and the ionic conductivity can be further improved.

In the present invention, the content of the constituent component derived from a macromonomer having a number average molecular weight of 2,000 or more is preferably 10 to 50% by mass, and preferably 15 to 45% by mass in the constituent components of the polymer constituting the binder. % Is more preferable, and 20 to 40% by mass is further preferable. When the content of the component derived from the macromonomer having a number average molecular weight of 2,000 or more is within the above range, the solid electrolyte is obtained by heating and drying in the production process of the sheet for an all-solid secondary battery or the all-solid secondary battery. Damage to the layer and / or electrode active material layer is less likely to occur, and ion conductivity can be further improved.

The polymer constituting the binder used in the present invention may contain a component other than the component represented by the general formula (1) and a component derived from a macromonomer having a number average molecular weight of 2,000 or more. Examples of such a component include a component derived from the following monomer (b), and the content thereof is preferably 1 to 70% by mass, more preferably 5 to 60% by mass, and 10 to 50%. More preferred is mass%.

(Monomer (b))
The monomer (b) is preferably a monomer having one polymerizable unsaturated bond, and for example, various vinyl monomers and acrylic monomers can be applied. In the present invention, it is particularly preferable to use an acrylic monomer. More preferably, a monomer selected from (meth) acrylic acid monomers, (meth) acrylic acid ester monomers, and (meth) acrylonitrile is used.

The vinyl monomer is preferably a monomer represented by the following formula (b-1).

In the formula, R ⁸ represents a hydrogen atom, an alkyl group (preferably 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 6 carbon atoms), an alkenyl group (preferably 2 to 24 carbon atoms, preferably 2 to 12 carbon atoms). More preferably, 2 to 6 are particularly preferable, an alkynyl group (preferably having 2 to 24 carbon atoms, more preferably 2 to 12, and particularly preferably 2 to 6), or an aryl group (preferably having 6 to 22 carbon atoms, 6 To 14 are more preferable). Of these, a hydrogen atom or an alkyl group is preferable, and a hydrogen atom or a methyl group is more preferable.

R ⁹ is a hydrogen atom, an alkyl group (preferably having 1 to 24 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 6 carbon atoms), or an alkenyl group (preferably having 2 to 12 carbon atoms, more preferably 2 to 6 carbon atoms). ), Aryl group (preferably having 6 to 22 carbon atoms, more preferably 6 to 14 carbon atoms), aralkyl group (preferably having 7 to 23 carbon atoms, more preferably 7 to 15 carbon atoms), cyano group, carboxy group, hydroxy group, thiol Group, sulfonic acid group, phosphoric acid group, phosphonic acid group, aliphatic heterocyclic group containing oxygen atom (preferably having 2 to 12 carbon atoms, more preferably 2 to 6), or amino group (NR ^N ₂ : R ^N is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms in accordance with the above definition. Of these, a methyl group, ethyl group, propyl group, butyl group, cyano group, ethenyl group, phenyl group, carboxy group, sulfanyl (thiol group), sulfonic acid group and the like are preferable.
R ⁹ may further have a substituent T described later. Of these, a carboxy group, a halogen atom (fluorine atom, etc.), a hydroxy group, an alkyl group and the like may be substituted.
The carboxy group, hydroxy group, sulfonic acid group, phosphoric acid group, and phosphonic acid group may be esterified with, for example, an alkyl group having 1 to 6 carbon atoms.
The aliphatic heterocyclic group containing an oxygen atom is preferably an epoxy group-containing group, an oxetane group-containing group, a tetrahydrofuryl group-containing group, or the like.

L ¹ is an arbitrary linking group, and examples of the linking group L described later are given. Specifically, an alkylene group having 1 to 6 (preferably 1 to 3) carbon atoms, an alkenylene group having 2 to 6 (preferably 2 to 3) carbon atoms, and 6 to 24 (preferably 6 to 10) carbon atoms. Arylene group, oxygen atom, sulfur atom, imino group (NR ^N ), carbonyl group, phosphate linking group (—O—P (OH) (O) —O—), phosphonic acid linking group (—P (OH) ( And groups relating to O)-O-), or combinations thereof. The linking group may have an arbitrary substituent. The preferable number of connecting atoms and the number of connecting atoms are the same as described later. As an arbitrary substituent, the substituent T is mentioned, For example, an alkyl group or a halogen atom is mentioned.

M is 0 or 1.

As the acrylic monomer, in addition to the above (b-1), those represented by the following formula (b-2) or (b-3) are preferable.

R ⁸ and m are as defined in the above formula (b-1).
R ¹⁰ has the same meaning as R ⁹ . However, preferred examples thereof include a hydrogen atom, an alkyl group, an aryl group, a carboxy group, a thiol group, a phosphoric acid group, a phosphonic acid group, an aliphatic heterocyclic group containing an oxygen atom, and an amino group (NR ^N ₂ ). Is mentioned.
L ² is an arbitrary linking group, and an example of L ¹ is preferable, and an oxygen atom, an alkylene group having 1 to 6 carbon atoms (preferably 1 to 3), or an alkylene group having 2 to 6 carbon atoms (preferably 2 to 3). An alkenylene group, a carbonyl group, an imino group (NR ^N ), or a group related to a combination thereof is more preferable.
L ³ is a linking group, and an example of L ² is preferable, and an alkylene group having 1 to 6 carbon atoms (preferably 1 to 3) is more preferable.
m represents an integer of 1 to 20, preferably an integer of 1 to 15, and more preferably an integer of 1 to 10.

In the above formulas (b-1) to (b-3), any group which may take a substituent such as an alkyl group, an aryl group, an alkylene group or an arylene group may be substituted as long as the effects of the present invention are maintained. It may have a group. Examples of the optional substituent include a substituent T, and specifically include a halogen atom, a hydroxy group, a carboxy group, a thiol group, an acyl group, an acyloxy group, an alkoxy group, an aryloxy group, an aryloyl group, and an aryl group. You may have arbitrary substituents, such as a royloxy group and an amino group.

Examples of the monomer (b) are given below, but the present invention is not construed as being limited thereby. V in the following formula represents 1 to 90.

Examples of the substituent T include the following.
An alkyl group (preferably an alkyl group having 1 to 20 carbon atoms, such as methyl, ethyl, isopropyl, t-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.), alkenyl group (Preferably an alkenyl group having 2 to 20 carbon atoms, such as vinyl, allyl, oleyl, etc.), alkynyl group (preferably an alkynyl group having 2 to 20 carbon atoms, such as ethynyl, butadiynyl, phenylethynyl, etc.), cycloalkyl group (Preferably a cycloalkyl group having 3 to 20 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc.), an aryl group (preferably an aryl group having 6 to 26 carbon atoms such as phenyl, 1-naphthyl, etc. 4-methoxyphenyl, 2-chlorophenyl, -Methylphenyl and the like), a heterocyclic group (preferably a heterocyclic group having 2 to 20 carbon atoms, preferably a 5- or 6-membered heterocyclic group having at least one oxygen atom, sulfur atom or nitrogen atom, For example, tetrahydropyran, tetrahydrofuran, 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-oxazolyl and the like, an alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, such as methoxy , Ethoxy, isopropyloxy, benzyloxy, etc.), aryloxy groups (preferably aryloxy groups having 6 to 26 carbon atoms, such as phenoxy, 1-naphthyloxy, 3-methylphenoxy, 4-methoxyphenoxy, etc.), alkoxycarbonyl Group (preferably an alkoxy group having 2 to 20 carbon atoms) Bonyl groups such as ethoxycarbonyl, 2-ethylhexyloxycarbonyl, etc., aryloxycarbonyl groups (preferably aryloxycarbonyl groups having 6 to 26 carbon atoms such as phenoxycarbonyl, 1-naphthyloxycarbonyl, 3-methylphenoxycarbonyl) 4-methoxyphenoxycarbonyl, etc.), an amino group (preferably an amino group having 0 to 20 carbon atoms, an alkylamino group, an arylamino group, such as amino, N, N-dimethylamino, N, N-diethylamino, N-ethylamino, anilino, etc.), a sulfamoyl group (preferably a sulfamoyl group having 0 to 20 carbon atoms, such as N, N-dimethylsulfamoyl, N-phenylsulfamoyl etc.), an acyl group (alkylcarbonyl group, An alkenylcarbonyl group, Including alkynylcarbonyl group, arylcarbonyl group, heterocyclic carbonyl group, preferably acyl group having 1 to 20 carbon atoms, for example, acetyl, propionyl, butyryl, octanoyl, hexadecanoyl, acryloyl, methacryloyl, crotonoyl, benzoyl, naphthoyl , Nicotinoyl, etc.), acyloxy groups (alkylcarbonyloxy groups, alkenylcarbonyloxy groups, alkynylcarbonyloxy groups, arylcarbonyloxy groups, heterocyclic carbonyloxy groups, preferably acyloxy groups having 1 to 20 carbon atoms such as acetyl Oxy, propionyloxy, butyryloxy, octanoyloxy, hexadecanoyloxy, acryloyloxy, methacryloyloxy, crotonoyloxy, benzoyloxy, naphtho Luoxy, nicotinoyloxy and the like), aryloyloxy groups (preferably aryloyloxy groups having 7 to 23 carbon atoms, such as benzoyloxy), carbamoyl groups (preferably carbamoyl groups having 1 to 20 carbon atoms, such as N N-dimethylcarbamoyl, N-phenylcarbamoyl, etc.), an acylamino group (preferably an acylamino group having 1 to 20 carbon atoms, such as acetylamino, benzoylamino, etc.), an alkylthio group (preferably an alkylthio group having 1 to 20 carbon atoms). For example, methylthio, ethylthio, isopropylthio, benzylthio, etc.), arylthio groups (preferably arylthio groups having 6 to 26 carbon atoms, such as phenylthio, 1-naphthylthio, 3-methylphenylthio, 4-methoxyphenylthio, etc.), Alkylsulfonyl group ( Preferably, it is 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 alkylsilyl group ( Preferably an alkylsilyl group having 1 to 20 carbon atoms, such as monomethylsilyl, dimethylsilyl, trimethylsilyl, triethylsilyl, etc.), an arylsilyl group (preferably an arylsilyl group having 6 to 42 carbon atoms, such as triphenylsilyl, etc.) A phosphoryl group (preferably a phosphate 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 Hosufini having 0 to 20 carbon atoms Group, for example, ^-P (R _P) 2), a sulfo group (sulfonic acid group), hydroxy group, sulfanyl group, a cyano group, a halogen atom (e.g. fluorine atom, a chlorine atom, a bromine atom, and an iodine atom) of .
In addition, each of the groups listed as the substituent T may be further substituted with the above-described substituent T.

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.

The polymer constituting the binder used in the present invention can be synthesized with reference to, for example, Japanese Patent No. 6253155 and International Publication No. 2017/099248.

The binder used in the present invention may be used singly or in combination of two or more.

The binder content in the solid electrolyte composition is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and 0.3% by mass or more in the solid content. It is particularly preferred. As an upper limit, it is preferable that it is 30 mass% or less, It is more preferable that it is 20 mass% or less, It is especially preferable that it is 10 mass% or less.

The shape of the polymer constituting the binder is not particularly limited, and may be a particulate shape or an indefinite shape.
The polymer constituting the binder preferably has an average particle size of 10 nm to 50 μm in order to suppress a decrease in ionic conductivity between the sulfide-based inorganic solid electrolyte and the active material. More preferably, it is a particle.

The average particle size of the polymer particles constituting the binder is based on the measurement conditions and definitions described below unless otherwise specified.
The polymer particles constituting the binder are prepared by diluting a 1% by mass dispersion in a 20 ml sample bottle using an arbitrary solvent (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 apparatus LA-920 (trade name, manufactured by HORIBA), data acquisition was performed 50 times using a measurement quartz cell 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 if 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, for example, in accordance with a method for measuring the average particle diameter of the polymer particles constituting the binder for the electrode material after disassembling the battery and peeling off the electrode. The measurement can be performed by excluding the measured value of the average particle diameter of the particles other than the polymer particles constituting the binder that has been measured in advance.

The number average molecular weight of the polymer forming the binder is not particularly limited. For example, 3000 or more are preferable, 5,000 or more are more preferable, and 10,000 or more are still more preferable. As an upper limit, 100,000 or less is practical.

-Measurement of molecular weight-
In the present invention, the molecular weight of the polymer or macromonomer is the number average molecular weight unless otherwise specified, and the number average molecular weight in terms of standard polystyrene is measured by gel permeation chromatography (GPC). The measurement method is basically a value measured by the following condition 1 or condition 2 (priority) method. However, an appropriate eluent may be selected and used depending on the polymer type.
(Condition 1)
Column: Two TOSOH TSKgel Super AWM-Hs are connected Carrier: 10 mM LiBr / N-methylpyrrolidone Measurement temperature: 40 ° C.
Carrier flow rate: 1.0 mL / min
Sample concentration: 0.1% by mass
Detector: RI (refractive index) detector (Condition 2) priority Column: TOSOH TSKgel Super HZM-H, TOSOH TSKgel Super HZ4000, TOSOH TSKgel Super HZ2000 connected to column Carrier: Tetrahydrofuran Measurement temperature: 40 ° C
Carrier flow rate: 1.0 mL / min
Sample concentration: 0.1% by mass
Detector: RI (refractive index) detector

<Dispersion medium>
The solid electrolyte composition of the present invention contains a dispersion medium (dispersion medium).
The dispersion medium only needs to disperse each of the above components, and examples thereof include various organic solvents. Examples of the organic solvent include alcohol compounds, ether compounds, amide compounds, amine compounds, ketone compounds, aromatic compounds, aliphatic compounds, nitrile compounds, ester compounds, and the like. Specific examples of the dispersion medium include the following: Can be mentioned.

Examples of the alcohol compound include methyl alcohol, ethyl alcohol, 1-propyl alcohol, 2-propyl alcohol, 2-butanol, ethylene glycol, propylene glycol, glycerin, 1,6-hexanediol, cyclohexanediol, sorbitol, xylitol, 2 -Methyl-2,4-pentanediol, 1,3-butanediol, 1,4-butanediol.

Examples of ether compounds 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, triethylene glycol, polyethylene glycol, propylene glycol monomethyl ether, dipropylene glycol. Monomethyl ether, tripropylene glycol monomethyl ether, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether, etc.), dialkyl ethers (dimethyl ether, diethyl ether, diisopropyl ether, dibutyl ether, etc.), cyclic ethers (tetrahydrofuran, dioxy ether) Emissions (1,2, including 1,3- and 1,4-isomers of), etc.).

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

Examples of the amine compound include triethylamine, diisopropylethylamine, tributylamine and the like.
Examples of the ketone compound include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.
Examples of the aromatic compound include benzene, toluene, xylene and the like.
Examples of the aliphatic compound include hexane, heptane, octane, decane and the like.
Examples of the nitrile compound include acetonitrile, propylonitrile, isobutyronitrile, and the like.
Examples of the ester compound include ethyl acetate, butyl acetate, propyl acetate, butyl butyrate, and butyl pentanoate.
Examples of the non-aqueous dispersion medium include the above aromatic compounds and aliphatic compounds.

In the present invention, among others, it is preferable to use a solubility parameter (SP value) ^{21 MPa 1/2} or less of the dispersion medium, more preferably 18 ~ 20.5 MPa ^1/2, more preferably 19 ~ ^{20 MPa 1/2.} By using a dispersion medium having an SP value in the above range, the ring α and the dispersion medium exhibit high affinity to suppress binder aggregation.
Specific examples of the dispersion medium having an SP value of 21 MPa ^1/2 or less include toluene, diethyl ether, cyclooctane, butyl butyrate, cyclohexane, diisobutyl ketone and heptane.
In this specification, the SP value of the dispersion medium is a value determined by the Hoy method.

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, the content of the dispersion medium in the solid electrolyte composition is not particularly limited and can be appropriately set. For example, in the solid electrolyte composition, 20 to 99% by mass is preferable, 25 to 70% by mass is more preferable, and 30 to 60% by mass is particularly preferable.

<Lithium salt>
The solid electrolyte composition of the present invention preferably contains a lithium salt (supporting electrolyte).
The lithium salt and the like that can be used in the present invention is preferably a lithium salt that is usually used in this type of product, and is not particularly limited.

(L-1) Inorganic lithium salts: inorganic fluoride salts such as LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiSbF ₆ ; perhalogenates such as LiClO ₄ , LiBrO ₄ , LiIO ₄ ; inorganic chloride salts such as LiAlCl ₄ etc.

(L-2) Fluorine-containing organic lithium salt: perfluoroalkanesulfonate such as LiCF ₃ SO ₃ ; LiN (CF ₃ SO ₂ ) ₂ , LiN (CF ₃ CF ₂ SO ₂ ) ₂ , LiN (FSO ₂ ) ₂ , Perfluoroalkanesulfonylimide salts such as LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ); perfluoroalkanesulfonylmethide salts such as LiC (CF ₃ SO ₂ ) ₃ ; Li [PF ₅ (CF ₂ CF ₂ CF ₃ )], Li [PF ₄ (CF ₂ CF ₂ CF ₃ ) ₂ ], Li [PF ₃ (CF ₂ CF ₂ CF ₃ ) ₃ ], Li [PF ₅ (CF ₂ CF ₂ CF ₂ CF ₃ _{_{_{_{)], Li [PF 4 (}}}} CF 2 CF 2 CF 2 CF 3) 2], Li [PF 3 (CF 2 CF 2 CF 2 CF 3) 3] fluoroalkyl fluoride such as potash Acid salts, and the like.

(L-3) Oxalatoborate salt: lithium bis (oxalato) borate, lithium difluorooxalatoborate and the like.
Among these, LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiSbF ₆ , LiClO ₄ , Li (Rf ¹ SO ₃ ), LiN (Rf ¹ SO ₂ ) ₂ , LiN (FSO ₂ ) ₂ , and LiN (Rf ¹ SO ₂ ) (Rf ² SO ₂ ), preferably LiPF ₆ , LiBF ₄ , LiN (Rf ¹ SO ₂ ) ₂ , LiN (FSO ₂ ) ₂ , and LiN (Rf ¹ SO ₂ ) (Rf ² SO ₂ ) More preferred are imide salts. Here, Rf ¹ and Rf ² each represent a perfluoroalkyl group.
In addition, lithium salt may be used individually by 1 type, or may combine 2 or more types arbitrarily.

When the solid electrolyte composition of the present invention contains a lithium salt, the content of the lithium salt is preferably 0.1 parts by mass or more and more preferably 5 parts by mass or more with respect to 100 parts by mass of the solid electrolyte. As an upper limit, 50 mass parts or less are preferable, and 20 mass parts or less are more preferable.

<Active material>
The solid electrolyte composition of the present invention may contain an active material capable of inserting and releasing metal ions belonging to Group 1 or Group 2 of the Periodic Table. As described below, the active material includes a positive electrode active material and a negative electrode active material. A transition metal oxide (preferably a transition metal oxide) that is a positive electrode active material or a metal oxide that is a negative electrode active material Or the metal which can form an alloy with lithium, such as Sn, Si, Al, and In, is preferable.
In the present invention, a solid electrolyte composition containing an active material (positive electrode active material or negative electrode active material) is sometimes referred to as an electrode composition (positive electrode composition or 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 / or release lithium ions. The material is not particularly limited as long as it has the above characteristics, and may be a transition metal oxide or an element that can be complexed with Li such as sulfur.
Among these, 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 and B) may be mixed. The mixing amount is preferably 0 ~ 30 mol% relative to the amount of the transition metal element ^{M a (100mol%).} That the molar ratio of li / ^{M a} was synthesized were mixed so that 0.3 to 2.2, more preferably.
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 halogenated 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 (nickel cobalt lithium aluminum oxide [NCA]), LiNi _1/3 Co _1/3 Mn _1/3 O ₂ (nickel manganese lithium cobalt oxide [NMC]), LiNi _0.5 Mn _0.5 O ₂ ( Lithium manganese nickelate).
As specific examples of transition metal oxides having (MB) spinel structure, 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 iron phosphate salts such as LiFePO ₄ and Li ₃ Fe ₂ (PO ₄ ) ₃ , iron pyrophosphates such as LiFeP ₂ O ₇ , LiCoPO _{4, and the} like. And monoclinic Nasicon type vanadium phosphate salts such as Li ₃ V ₂ (PO ₄ ) ₃ (vanadium lithium phosphate).
(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 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 material may be used alone or in combination of two or more.
When forming a 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. It can be determined as appropriate according to the designed battery capacity, for example, 1 to 100 mg / cm ² .

The content of the positive electrode active material in the solid electrolyte composition is not particularly limited, and is preferably 10 to 97% by mass, more preferably 30 to 95% by mass, and still more preferably 40 to 93% by mass at a solid content of 100% by mass. 50 to 90% by mass is particularly preferable.

(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 / or 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 or a lithium alloy such as a lithium aluminum alloy, and , Sn, Si, Al, In, and other metals capable of forming an alloy with lithium. Among these, a carbonaceous material or a lithium composite oxide is preferably used from the viewpoint of reliability. Further, 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) resin or 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. And mesophase microspheres, graphite whiskers, flat graphite and the like.

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

As the metal oxide and metal composite oxide applied as the negative electrode active material, an amorphous oxide is particularly preferable, and chalcogenite which is a reaction product of a metal element and a group 16 element 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. The strongest intensity of crystalline diffraction lines seen from 2 ° to 40 ° to 70 ° is 100 times the diffraction line intensity at the peak of the broad scattering band seen from 2 ° to 20 °. It is preferable that it is 5 times or less, and it is particularly preferable not to have a crystalline diffraction line.

Among the compound group consisting of the above amorphous oxide and chalcogenide, an amorphous oxide of a metalloid element and a 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 electrodes is suppressed, and lithium ion secondary. This is preferable in that the battery life can be improved.

In the present invention, hard carbon or graphite is preferably used, and graphite is more preferably used. In the present invention, the carbonaceous materials may be used singly or in combination of two or more.

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 Li ion occlusion per unit weight increases. Therefore, the battery capacity can be increased. As a result, there is an advantage that the battery driving time can be extended.

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

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

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, an ordinary pulverizer or classifier is used. For example, a mortar, a ball mill, a sand mill, a vibrating ball mill, a satellite ball mill, a planetary ball mill, a swirling air flow type jet mill or a sieve is preferably used. When pulverizing, wet pulverization in the presence of water or an organic solvent such as methanol can be performed as necessary. In order to obtain a desired particle diameter, classification is preferably performed. There is no restriction | limiting in particular as a classification method, A sieve, an air classifier, etc. can be used as needed. 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 said negative electrode active material may be used individually by 1 type, or may be used in combination of 2 or more type.
When forming the negative electrode active material layer, 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. It can be determined as appropriate according to the designed battery capacity, for example, 1 to 100 mg / cm ² .

The content of the negative electrode active material in the solid electrolyte composition is not particularly limited, and is preferably 10 to 90% by mass, more preferably 20 to 85% by mass, and more preferably 30 to 80% by mass with a solid content of 100% by mass. % Is more preferable, and 40 to 75% by mass is even more preferable.

(Coating with active material)
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. Specific examples include 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 surface treatment with actinic rays or an active gas (plasma or the like) before and after the surface coating.

<Conductive aid>
The solid electrolyte composition of the present invention may contain a conductive auxiliary agent used for improving the electronic conductivity of the active material, if necessary. As the conductive auxiliary agent, a general conductive auxiliary 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 or carbon nanotube, which are electron conductive materials Carbon fibers such as graphene, carbonaceous materials such as graphene or 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. Moreover, 1 type of these may be used and 2 or more types may be used.
When the solid electrolyte composition of the present invention contains a conductive aid, the content of the conductive aid in the solid electrolyte composition is preferably 0 to 10% by mass.

(Preparation of solid electrolyte composition)
The solid electrolyte composition of the present invention can be prepared, preferably as a slurry, by mixing an inorganic solid electrolyte, a binder and a dispersion medium, and optionally other components, for example, using various mixers. .
The mixing method is not particularly limited, and may be mixed all at once or sequentially.
Although it does not restrict | limit especially as a mixer, For example, a ball mill, bead mill, a planetary mixer, a blade mixer, a roll mill, a kneader, and a disk mill are mentioned. The mixing conditions are not particularly limited. For example, the mixing temperature is set to 10 to 60 ° C., the mixing time is set to 5 minutes to 5 hours, and the rotation speed is set to 10 to 700 rpm (rotation per minute). When a ball mill is used as the mixer, it is preferable to set the rotational speed at 150 to 700 rpm and the mixing time at 5 minutes to 24 hours at the mixing temperature. In addition, it is preferable that the compounding quantity of each component is set so that it may become the said content.
The environment for mixing is not particularly limited, and examples thereof include dry air or inert gas.

The composition for forming an active material layer according to the present invention can highly disperse solid particles while suppressing reaggregation of solid particles, and can maintain a dispersed state of the composition (shows high dispersion stability). Therefore, as described later, it is preferably used as a material for forming an active material layer of an all-solid secondary battery or an electrode sheet for an all-solid secondary battery.

[All-solid-state secondary battery sheet]
The sheet for an all-solid-state secondary battery of the present invention is a sheet-like molded body that can form a constituent layer of the 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), an electrode, or a sheet preferably used for a laminate of an electrode and a solid electrolyte layer (an electrode for an all-solid secondary battery) Sheet) and the like. In the present invention, these various sheets may be collectively referred to as an all-solid secondary battery sheet.

The solid electrolyte sheet for an all-solid-state secondary battery according to the present invention may be a sheet having a solid electrolyte layer. The sheet | seat currently formed from may be sufficient. The solid electrolyte sheet for an all-solid-state secondary battery may have other layers as long as it has a solid electrolyte layer. Examples of other layers include a protective layer (release sheet), a current collector, and a coat layer.
Examples of the solid electrolyte sheet for an all-solid-state secondary battery of the present invention include a sheet having a solid electrolyte layer and, if necessary, a protective layer in this order on a substrate.
The base material is not particularly limited as long as it can support the solid electrolyte layer, and examples thereof include materials described later with reference to current collectors, sheet materials (plate bodies) of organic materials, 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 configuration and layer thickness of the solid electrolyte layer of the all-solid-state secondary battery sheet are the same as the configuration and layer thickness of the solid electrolyte layer described in the all-solid-state secondary battery of the present invention.

The electrode sheet for an all-solid-state secondary battery of the present invention (also simply referred to as “electrode sheet of the present invention”) may be an electrode sheet having an active material layer, and the active material layer is on the substrate (current collector). Even the sheet | seat formed in this may be a sheet | seat formed from an active material layer, without having a base material. 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 electrode sheet of the present invention may have the other layers described above as long as it has an active material layer. The layer thickness of each layer constituting the electrode sheet of the present invention is the same as the layer thickness of each layer described in the all-solid secondary battery described later.

[Manufacture of sheets for all-solid-state secondary batteries]
The method for producing the all-solid-state secondary battery sheet of the present invention is not particularly limited, and can be produced by forming each of the above layers using the solid electrolyte composition of the present invention. For example, a method of forming a layer (coating / drying layer) made of a solid electrolyte composition by forming a film (coating / drying) on a base material or a current collector (may be provided with another layer) if necessary. Can be mentioned. Thereby, the sheet | seat for all-solid-state secondary batteries which has a base material or an electrical power collector, and a coating dry layer as needed can be produced. Here, the coating and drying layer is a layer formed by applying the solid electrolyte composition of the present invention and drying the dispersion medium (that is, using the solid electrolyte composition of the present invention, and the solid of the present invention. A layer having a composition obtained by removing the dispersion medium from the electrolyte composition).
In the method for producing an all-solid-state secondary battery sheet of the present invention, each step such as coating and drying will be described in the following method for producing an all-solid-state secondary battery.

In the method for producing an all-solid-state secondary battery sheet of the present invention, the coating / drying layer obtained as described above can be pressurized. The pressurizing condition and the like will be described later in the method for manufacturing an all-solid secondary battery.
Moreover, in the manufacturing method of the sheet | seat for all-solid-state secondary batteries of this invention, a base material, a protective layer (especially peeling sheet), etc. can also be peeled.

The all-solid-state secondary battery sheet according to the present invention has at least one of a solid electrolyte layer and an active material layer formed of the solid electrolyte composition of the present invention, and effectively suppresses an increase in interfacial resistance between solid particles. Solid particles are firmly bound together. Therefore, it is suitably used as a sheet that can form a constituent layer of an all-solid-state secondary battery. In particular, when a sheet for an all-solid-state secondary battery is produced in a long line (even when wound during conveyance) and used as a wound battery, bending stress is applied to the solid electrolyte layer and the active material layer. Even if it acts, the binding state of the solid particles in the solid electrolyte layer and the active material layer can be maintained. When an all-solid-state secondary battery is manufactured using the sheet for an all-solid-state secondary battery manufactured by such a manufacturing method, high productivity and yield (reproducibility) can be realized while maintaining excellent battery performance.

[All-solid secondary battery]
An all solid state secondary battery of the present invention comprises a positive electrode active material layer, a negative electrode active material layer facing the positive electrode active material layer, and a solid electrolyte layer disposed between the positive electrode active material layer and the negative electrode active material layer. Have. The positive electrode active material layer is formed on the positive electrode current collector as necessary to constitute a positive electrode. The negative electrode active material layer is formed on the negative electrode current collector as necessary to constitute the negative electrode.
At least one of the negative electrode active material layer, the positive electrode active material layer, and the solid electrolyte layer is preferably formed of the solid electrolyte composition of the present invention. Among them, all the layers are formed of the solid electrolyte composition of the present invention. More preferably. The active material layer or the solid electrolyte layer formed of the solid electrolyte composition of the present invention is preferably the same as that in the solid content of the solid electrolyte composition of the present invention with respect to the component species to be contained and the content ratio thereof. . In addition, a well-known material can be used when an active material layer or a solid electrolyte layer is not formed with the solid electrolyte composition of this invention.
The thicknesses of the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer are not particularly limited. The thickness of each layer is preferably 10 to 1,000 μm, more preferably 20 μm or more and less than 500 μm, considering the dimensions of a general all solid state secondary battery. 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 and the negative electrode active material layer is 50 μm or more and less than 500 μm.
Each of the positive electrode active material layer and the negative electrode active material layer may include a current collector on the side opposite to the solid electrolyte layer.

[Case]
The all-solid-state secondary battery of the present invention may be used as an all-solid-state secondary battery with the above-mentioned structure depending on the application. Is preferred. The housing may be metallic or made of resin (plastic). In the case of using a metallic material, for example, an aluminum alloy or a stainless steel material can be used. The metallic 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 via a gasket for preventing a short circuit.

Hereinafter, an all-solid secondary battery according to a preferred embodiment of the present invention will be described with reference to FIG. 1, but the present invention is not limited thereto.

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 an adjacent 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 illustrated example, a light bulb is adopted as a model for the operating part 6 and is lit by discharge.

When the all-solid-state secondary battery having the layer configuration shown in FIG. 1 is placed in a 2032 type coin case, this all-solid-state secondary battery is referred to as an all-solid-state secondary battery electrode sheet, A battery produced by placing it in a 2032 type coin case may be referred to as an all-solid secondary battery.

(Positive electrode active material layer, solid electrolyte layer, negative electrode active material layer)
In the all-solid-state secondary battery 10, all of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer are formed of the solid electrolyte composition of the present invention. This all-solid-state secondary battery 10 has a small electric resistance and exhibits excellent battery performance. The inorganic solid electrolyte and binder 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, either or both of the positive electrode active material layer and the negative electrode active material layer may be simply referred to as an active material layer or an electrode active material layer. One or both of the positive electrode active material and the negative electrode active material may be simply referred to as an active material or an electrode active material.

In the present invention, when the binder is used in combination with solid particles such as an inorganic solid electrolyte or an active material, as described above, an increase in the interfacial resistance between the solid particles and an increase in the interfacial resistance between the solid particles and the current collector are suppressed. be able to. Furthermore, contact failure between the solid particles and peeling (peeling) of the solid particles from the current collector can be suppressed. Therefore, the all solid state secondary battery of the present invention exhibits excellent battery characteristics. In particular, the all-solid-state secondary battery of the present invention using the above-mentioned binder capable of binding solid particles and the like as described above is a process for producing an all-solid-state secondary battery sheet or an all-solid-state secondary battery, for example, as described above. Even when bending stress is applied, excellent battery characteristics can be maintained.

In the all-solid-state secondary battery 10, the negative electrode active material layer can be a lithium metal layer. Examples of the lithium metal layer include a layer formed by depositing or molding lithium metal powder, a lithium foil, a lithium vapor deposition film, and the like. Regardless of the thickness of the negative electrode active material layer, the thickness of the lithium metal layer can be, for example, 1 to 500 μm.

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 aluminum or stainless steel surface treated with carbon, nickel, titanium, or silver (forming a thin film) Among them, aluminum and aluminum alloys are more preferable.
In addition to aluminum, copper, copper alloy, stainless steel, nickel, 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, a 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.

[Manufacture of all-solid-state secondary batteries]
The all solid state secondary battery can be manufactured by a conventional method. Specifically, an all-solid secondary battery can be manufactured by forming each of the above layers using the solid electrolyte composition of the present invention. Thereby, an all-solid-state secondary battery having a small electric resistance and excellent battery performance can be manufactured. Details will be described below.

The all-solid-state secondary battery of the present invention includes a step of applying the solid electrolyte composition of the present invention on a base material (for example, a metal foil serving as a current collector) to form a film (forming a film). It can be manufactured via the (intermediate) method (method for manufacturing the sheet for an all-solid-state secondary battery of the present invention).
For example, a solid electrolyte composition containing a positive electrode active material is applied as a positive electrode material (positive electrode composition) on a metal foil that is a positive electrode current collector to form a positive electrode active material layer. A positive electrode sheet for a battery is prepared. Next, a solid electrolyte composition for forming a solid electrolyte layer is applied on the positive electrode active material layer to form a solid electrolyte layer. Furthermore, a solid electrolyte composition 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-state 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 produce 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. Further, a negative electrode active material layer is formed by applying a solid electrolyte composition containing a negative electrode active material as a negative electrode material (negative electrode composition) on a metal foil that is a negative electrode current collector, and forming an all-solid secondary A negative electrode sheet for a 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 is applied onto a substrate to produce a solid electrolyte sheet for an all-solid 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.
In the above production method, the solid electrolyte composition of the present invention may be used for any one of the positive electrode composition, the solid electrolyte composition, and the negative electrode composition. It is preferable to use it.

<Formation of each layer (film formation)>
The method for applying 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 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 even more 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 (coating dry layer). Further, 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 obtained, and good binding properties and good ionic conductivity can be obtained even without pressure.

As described above, when the solid electrolyte composition of the present invention is applied and dried, a coating / drying layer in which the interfacial resistance between the solid particles is small and the solid particles are firmly bound can be formed.

It is preferable to pressurize each layer or all-solid secondary battery after producing the applied solid electrolyte composition or 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. On the other hand, when the inorganic solid electrolyte and the binder coexist, pressing can be performed at a temperature higher than the glass transition temperature of the polymer forming the binder. However, it is generally a temperature that does not exceed the melting point of the polymer.
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 apply | coated simultaneously and application | coating drying press 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), 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 or 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 operating 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 are no particular restrictions on the application mode, for example, when installed in an electronic device, a notebook computer, pen input personal computer, mobile personal computer, electronic book player, mobile phone, cordless phone, pager, handy terminal, mobile fax, 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. Other consumer products include automobiles, electric vehicles, motors, lighting equipment, toys, game equipment, road conditioners, watches, strobes, cameras, medical equipment (such as pacemakers, hearing aids, and shoulder grinders). Furthermore, it can be used for various military use and space use. Moreover, it can also combine with a solar cell.

Hereinafter, the present invention will be described in more detail based on examples. The present invention is not construed as being limited thereby.

(Synthesis of macromonomer)
Into a 300 mL three-necked flask, 53.7 g of toluene was added, and the temperature was raised to 80 ° C. with stirring (solution A1). Separately, 17.1 g of ethyl methacrylate, 38.2 g of dodecyl methacrylate, 0.54 g of 3-mercaptopropionic acid and 0.55 g of V-601 (trade name, manufactured by Wako Pure Chemical Industries, Ltd.) were added to a 100 mL graduated cylinder and stirred. Dissolved uniformly (solution B1). Solution B1 was added dropwise to Solution A1 at 80 ° C. over 2 hours, and then further stirred at 80 ° C. for 2 hours and at 95 ° C. for 2 hours, and then cooled to room temperature. This polymerization solution was poured into methanol to precipitate a polymer, and the process of removing the solvent was repeated twice. Thereafter, 107 g of heptane was added to the precipitate to prepare a heptane solution. This heptane solution was used as a macromonomer solution. The solid content concentration of the solution was 41% by mass, and the polymer in the macromonomer solution had a mass average molecular weight (Mw) of 12,000 and a number average molecular weight (Mn) of 6,000. The macromonomer has the following structure. The component derived from this macromonomer is C-1 shown in Table 1 below.

(Synthesis of polymer constituting binder)
A polymer constituting the binder (S-1) was synthesized as follows.
In a 200 mL three-necked flask, 11.5 g of the macromonomer solution and 16.4 g of diisobutyl ketone were added, and the temperature was raised to 80 ° C. with stirring (solution A2). Separately, 1.67 g of 1-adamantyl methacrylate, 10.0 g of mono (2-acryloyloxyethyl) succinate, 14.8 g of diisobutyl ketone, V-601 (trade name, manufactured by Wako Pure Chemical Industries, Ltd.) in a 50 mL graduated cylinder 0.53 g was added and stirred to dissolve uniformly (solution B2). The solution B2 was added dropwise to the solution A2 at 80 ° C. over 2 hours, followed by polymerization at 80 ° C. for 2 hours and 90 ° C. for 2 hours, and then cooled to room temperature. Thus, a dispersion liquid in which a part of the binder was dispersed in diisobutyl ketone was obtained. This dispersion was used as binder (S-1). The polymerization reaction product had Mw of 75,000 and Mn of 16,000. The volume average particle diameter of the particulate binder constituting the dispersoid of the binder (S-1) was 200 nm.

Binders (S-2) to (S) are synthesized in the same manner as the synthesis of the polymer constituting the binder (S-1) except that monomers and macromonomers are used so that the constituents have the compositions shown in Table 1 below. Polymers constituting S-14) and (T-1) to (T-3) were synthesized. Each Mn and volume average particle diameter (particle diameter) are as shown in the following table.

(Synthesis of sulfide inorganic solid electrolyte (Li-PS glass))
Sulfide-based inorganic solid electrolytes are disclosed in T.W. Ohtomo, A .; Hayashi, M .; Tatsumisago, Y. et al. Tsuchida, S .; Hama, 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.

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 mortar. Incidentally, Li ₂ S and _P 2 _{S 5} at a molar ratio of _{_{_{Li 2 S: P 2 S 5}}} = 75: was 25.
66 zirconia beads having a diameter of 5 mm were introduced into a 45 mL container (made by Fritsch) made of zirconia, the whole mixture of the above lithium sulfide and diphosphorus pentasulfide was introduced, and the container was sealed under an argon atmosphere. A container is set on 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. 6.20 g of glass, hereinafter also referred to as “LPS”.

<Preparation of solid electrolyte composition>
Into a zirconia 45 mL container (manufactured by Fritsch), 180 pieces of zirconia beads having a diameter of 5 mm were added, and after adding the inorganic solid electrolyte shown in Table 2 below, the binder dispersion prepared above, and the dispersion medium, Fritsch A container was set on a planetary ball mill P-7 (trade name) manufactured by KK and mixed at room temperature for 2 hours at a rotation speed of 300 rpm to prepare a solid electrolyte composition. The binder content described in Table 2 below is the solid content.
When the solid electrolyte composition contains a conductive additive or a lithium salt, the above-mentioned inorganic solid electrolyte, the binder dispersion prepared above, the conductive additive or lithium salt, and a dispersion medium are combined to form a ball mill P- 7 to prepare a solid electrolyte composition.
When the solid electrolyte composition contains an active material, the active material was added and further mixed at room temperature at a rotation speed of 150 rpm for 5 minutes to prepare a solid electrolyte composition.

<Preparation of solid electrolyte-containing sheet>
Each solid electrolyte composition prepared above was coated on a stainless steel (SUS) foil having a thickness of 20 μm and a width of 30 mm, which is a current collector, with a bar coder. The SUS foil was placed on a hot plate with the bottom surface, heated at 150 ° C. for 10 minutes to volatilize and remove the dispersion medium, and a sheet for an all-solid-state secondary battery (length 50 mm, width 70 mm, thickness 1 mm) was produced. .

[Test Example 1 Ionic conductivity measurement]
About each said sheet | seat for all-solid-state secondary batteries, the range which does not have a defect part visually was cut out into two disk shape of diameter 14.5mm. The two sheets of solid electrolyte layers (electrode layers in the case of containing an active material) are bonded to form an ion conductivity measurement sheet 12, and a spacer and a washer (not shown in FIG. 2) are incorporated. It was put in a stainless steel 2032 type coin case 11. By crimping the 2032 type coin case 11, an ion conductivity measurement specimen 13 having a configuration shown in FIG. 2, which was clamped with a force of 8 Newtons (N), was produced.
Ion conductivity was measured using the test body for ion conductivity measurement 13 obtained above. Specifically, in a thermostatic bath at 30 ° C., AC impedance was measured using a 1255B FREQUENCY RESPONSE ANALYZER (trade name, manufactured by SOLARTRON) to a voltage amplitude of 5 mV and a frequency of 1 MHz to 1 Hz. Thereby, the resistance of the film thickness direction of the sheet | seat for all-solid-state secondary batteries (sheet for ion conductivity measurement) bonded together was calculated | required, and it calculated by following formula (1), and calculated | required ionic conductivity. The obtained ionic conductivity was applied to the following evaluation criteria and evaluated. "C" or higher is a pass of this test.

Ionic conductivity σ (mS / cm) = 1,000 × sample thickness (cm) / (resistance (Ω) × sample area (cm ² )) Equation (1)
[Sample film thickness means the total thickness of the solid electrolyte layer or electrode layer. ]

<Ionic conductivity evaluation criteria>
A: 0.60 ≦ σ <0.65
B: 0.50 ≦ σ <0.60
C: 0.40 ≦ σ <0.50
D: 0.30 ≦ σ <0.40
E: 0.20 ≦ σ <0.30
F: σ <0.20

[Test Example 2 Crack observation during drying]
The dispersion medium was removed by the same process as in Preparation Example 2, and it was confirmed that the residual amount of the dispersion medium in the all-solid-state secondary battery sheet was 100 ppm or less. About the said sheet | seat for all-solid-state secondary batteries, the presence or absence of the crack in the range of 30 mm x 50 mm among coating ranges was confirmed visually, and it applied and evaluated by the following evaluation criteria. "D" or higher is a pass of this test.

-Evaluation criteria-
A: No crack occurred.
B: 1 to 3 cracks occurred. All crack widths were less than 5 mm.
C: 4 to 6 cracks occurred. All crack widths were less than 5 mm.
D: Seven or more cracks occurred. All crack widths were less than 5 mm.
E: 1 to 3 cracks occurred. The width of at least one crack was 5 mm or more.
F: 4 to 6 cracks occurred. The width of at least one crack was 5 mm or more.
G: Seven or more cracks occurred. The width of at least one crack was 5 mm or more.

<Notes on the table>
DIBK: diisobutyl ketone DME: 1,2-dimethoxyethane LLT: Li _0.33 La _0.55 TiO ₃ (average particle size 3.25 μm, manufactured by Toshima Seisakusho)
NMC: LiNi _1/3 Co _1/3 Mn _1/3 O ₂ (lithium nickel manganese cobaltate)
NCA: LiNi _0.85 Co _0.10 Al _0.05 O ₂ (nickel cobalt lithium aluminum oxide)
AB: Acetylene black VGCF: trade name, carbon nanofiber manufactured by Showa Denko KK

As is apparent from Table 2, the c11 to c16 all-solid-state secondary battery sheet using a binder that does not satisfy the provisions of the present invention has low ionic conductivity, and the cracking test at the time of drying failed. As is apparent from the results of c11 and c14 using the binder (T-1), a binder containing a component having a cyclic structure in the side chain and a component derived from a macromonomer having a number average molecular weight of 2,000 or more It can be seen that the desired performance cannot be obtained because the constituent component having a cyclic structure in the side chain does not satisfy the general formula (1) of the present invention.
On the other hand, all of the examples of the present invention have high ionic conductivity, and it can be seen that the cracking test at the time of drying is at an acceptable level.

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. 2018-081672 filed in Japan on April 20, 2018, which is hereby incorporated herein by reference. Capture as part.

DESCRIPTION OF SYMBOLS 1 Negative electrode current collector 2 Negative electrode active material layer 3 Solid electrolyte layer 4 Positive electrode active material layer 5 Positive electrode current collector 6 Working part 10 All solid state secondary battery 11 Coin case 12 Sheet for ion conductivity measurement 13 Test for ion conductivity measurement Body (coin battery)

Claims

A polymer comprising an inorganic solid electrolyte having ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, a binder, and a dispersion medium, and constituting the binder is represented by the following general formula (1). And a solid electrolyte composition containing a constituent derived from a macromonomer having a number average molecular weight of 2,000 or more.

In the formula, α represents a ring. L represents —O—, —NR 4 — or —S—. R 1 to R 4 represent a hydrogen atom or a monovalent substituent. * Indicates a connecting part of the constituent components.
The solid electrolyte composition according to claim 1, wherein the ring α has a single ring or a bridged ring structure.
The solid electrolyte composition according to claim 1 or 2, wherein the ring α is represented by any one of the following general formulas (I) to (III).

In the formula, Y and Z represent —CR 5 R 6 —, —O—, —NR 5 — or —S—. L 1 and L 2 represent a divalent linking group. R 5 and R 6 represent a hydrogen atom or a monovalent substituent. A wavy line indicates a coupling portion with L.
The content of the constituent component represented by the general formula (1) is 0.01 to 50% by mass in the constituent components of the polymer constituting the binder (B). 2. The solid electrolyte composition according to item 1.
Wherein L is -O- or -NR 4 - shows a solid electrolyte composition according to any one of claims 1 to 4.
The solid electrolyte composition according to claim 3, wherein Y in the general formula (I) represents -CR 5 R 6- and Z in the general formula (II) represents -CR 5 R 6- .
The solid electrolyte composition according to claim 3, wherein the ring α is represented by the general formula (III).
The solid electrolyte composition according to any one of claims 1 to 7, wherein the content of the constituent component derived from the macromonomer is 10 to 50% by mass in the constituent components of the polymer constituting the binder.
The solid electrolyte composition according to any one of claims 1 to 8, wherein the solubility parameter of the dispersion medium is 21 MPa 1/2 or less.
The solid electrolyte composition according to any one of claims 1 to 9, comprising a lithium salt.
The solid electrolyte composition according to any one of claims 1 to 10, comprising an active material.
The solid electrolyte composition according to any one of claims 1 to 11, comprising a conductive additive.
The solid electrolyte composition according to any one of claims 1 to 12, wherein the inorganic solid electrolyte is a sulfide-based inorganic solid electrolyte.
An all-solid secondary battery sheet having a layer composed of the solid electrolyte composition according to any one of claims 1 to 13.
An all solid state secondary battery comprising a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order,
The all-solid secondary, wherein at least one of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer is a layer composed of the solid electrolyte composition according to any one of claims 1 to 13. battery.
A method for producing a sheet for an all-solid-state secondary battery, wherein the solid electrolyte composition according to any one of claims 1 to 13 is formed into a film.
A method for producing an all-solid secondary battery for producing an all-solid secondary battery using the production method according to claim 16.