Inorganic solid electrolyte composition, sheet for all-solid-state secondary battery, all-solid-state secondary battery, and method for manufacturing sheet for all-solid-state secondary battery and all-solid-state secondary battery

Abstract

The present invention provides an inorganic solid electrolyte composition that exhibits excellent dispersion and coating properties and achieves excellent cycle characteristics, a sheet for an all-solid-state secondary battery and an all-solid-state secondary battery using the inorganic solid electrolyte composition, and methods for manufacturing the sheet and the all-solid-state secondary battery. The inorganic solid electrolyte composition for an all-solid-state secondary battery comprises an inorganic solid electrolyte, a polymer binder, and a dispersion medium. The polymer binder has an adsorption rate of 50% or less for the inorganic solid electrolyte, and the inorganic solid electrolyte and the polymer binder satisfy a specific relationship with respect to surface energy.

Description

Technical Field

[0001] The present invention relates to an inorganic solid electrolyte composition, a sheet for an all-solid-state secondary battery, an all-solid-state secondary battery, and a method for manufacturing the sheet for an all-solid-state secondary battery and the all-solid-state secondary battery. Background Art

[0002] In an all-solid-state secondary battery, all negative electrodes, electrolytes, and positive electrodes are made of solids, which can significantly improve the safety or reliability of batteries that use organic electrolytes. It can also extend the lifespan. In addition, an all-solid-state secondary battery can be configured to have a structure in which the electrodes and electrolytes are directly arranged and arranged in series. Therefore, compared to secondary batteries that use organic electrolytes, it can have a high energy density and is expected to be applied to electric vehicles or large storage batteries.

[0003] In such all-solid-state secondary batteries, the materials forming the constituent layers (solid electrolyte layer, negative electrode active material layer, positive electrode active material layer, etc.) include inorganic solid electrolytes, active materials, etc. Inorganic solid electrolytes, especially oxide-based inorganic solid electrolytes and sulfide-based inorganic solid electrolytes, have attracted attention in recent years as electrolyte materials with high ionic conductivity close to that of organic electrolytes.

[0004] Materials containing the above-mentioned inorganic solid electrolytes and the like have been proposed as materials for forming the constituent layers of all-solid-state secondary batteries (constituent layer-forming materials). For example, Patent Document 1 describes a solid electrolyte composition comprising an inorganic solid electrolyte (A) having ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, binder particles (B) having an average particle size of 10 nm to 1,000 nm, composed of a polymer having a macromonomer (X) with a number average molecular weight of 1,000 or more incorporated as a side chain component, and a dispersion medium (C).

[0005] Previous technical literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-088486 Summary of the Invention

[0008] Technical issues to be solved by the invention

[0009] When the constituent layer is formed by solid particle materials (inorganic solid electrolytes, active materials, conductive additives, etc.), from the perspective of improving the battery performance (such as cycle characteristics) of the all-solid-state secondary battery, it is preferred that the constituent layer forming material has excellent properties such as dispersibility and coating suitability.

[0010] In recent years, from reducing environmental load, and then the viewpoint of reducing manufacturing cost, as constituent layer formation material, the high concentration composition (concentrated slurry) of using to improve solid content concentration is being studied.But, along with the raising of the solid content concentration of composition, the characteristic of usual composition is greatly deteriorated.Therefore, even in high concentration composition, also not easy to realize the dispersion characteristics of suppressing solid particle material (also referred to as solid particles.) agglomeration etc. are excellent and easily form the characteristic (surface property) of the coating film with flat surface and even make the constituent layer formation material of the coating suitability excellence of the characteristic (adhesion) that solid particles and substrate are close-fitting.Even if using the binder particles put down in writing in patent documentation 1, also be difficult to fully realize the composition having dispersibility and coating suitability concurrently, need further research.

[0011] Furthermore, the rapid development of research and development for the advancement of electric vehicles and their practical application has led to increasing demands for higher performance in all-solid-state secondary batteries. To meet these demands, it is crucial to ensure that the materials forming the constituent layers exhibit enhanced properties.

[0012] The present invention aims to provide an inorganic solid electrolyte composition having excellent dispersion properties and coating suitability, which, when used as a material for forming a constituent layer of an all-solid-state secondary battery, can achieve excellent cycle characteristics. Furthermore, the present invention aims to provide an all-solid-state secondary battery sheet and an all-solid-state secondary battery using the inorganic solid electrolyte composition, as well as methods for manufacturing the all-solid-state secondary battery sheet and the all-solid-state secondary battery.

[0013] Means for solving technical problems

[0014] The present inventors have focused on the results of repeated in-depth studies on polymer binders used in conjunction with solid particles such as inorganic solid electrolytes and dispersion media, and have found that by combining an inorganic solid electrolyte and a polymer binder that satisfies the relationship specified by the formula (1) described below with respect to surface energy between the inorganic solid electrolytes and that exhibits an adsorption rate of 50% or less on the inorganic solid electrolyte, it is possible to suppress the aggregation or precipitation of the inorganic solid electrolyte. Therefore, by using the inorganic solid electrolyte composition as a constituent layer forming material, it has been found that a sheet for all-solid-state secondary batteries with a constituent layer having a flat coating surface, good surface properties, and excellent adhesion, as well as an all-solid-state secondary battery with excellent cycle characteristics, can be obtained. Based on these insights, the present invention has been further repeatedly studied to complete the present invention.

[0015] That is, the above-mentioned problems are solved by the following means.

[0016] <1>

[0017] An inorganic solid electrolyte composition comprising an inorganic solid electrolyte having ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, a polymer binder, and a dispersion medium, and for use in an all-solid-state secondary battery, wherein:

[0018] The adsorption rate of the polymer binder in the dispersion medium to the inorganic solid electrolyte is 50% or less.

[0019] The inorganic solid electrolyte and the polymer binder satisfy the relationship defined by the following formula (1) with respect to surface energy.

[0020] (Xse-Xba) 2 +(Yse-Yba) 2 ≤R 2 Formula (1)

[0021] Wherein, Xse represents the dispersive component of the surface energy of the inorganic solid electrolyte, and Yse represents the polar component of the surface energy of the inorganic solid electrolyte. Xba represents the dispersive component of the surface energy of the polymer binder, and Yba represents the polar component of the surface energy of the polymer binder. R is 20.

[0022] <2>

[0023] The inorganic solid electrolyte-containing composition according to <1>, wherein

[0024] The adsorption rate is 5% or more and less than 30%.

[0025] <3>

[0026] The inorganic solid electrolyte-containing composition according to <1> or <2> further contains an active material, wherein the active material and the polymer binder satisfy the relationship defined by the following formula (2) with respect to surface energy.

[0027] (Xam-Xba) 2 +(Yam-Yba) 2 ≤r 2 Formula (2)

[0028] Wherein, Xam represents the dispersive component of the surface energy of the active material, Yam represents the polar component of the surface energy of the active material, Xba represents the dispersive component of the surface energy of the polymer binder, and Yba represents the polar component of the surface energy of the polymer binder. r is 30.

[0029] <4>

[0030] The inorganic solid electrolyte-containing composition according to <3>, wherein

[0031] The inorganic solid electrolyte, the polymer binder, and the active material satisfy the relationship defined by the following formula (3) with respect to surface energy.

[0032] R SE +R AM ≤30 Formula (3)

[0033] Where R SE 2 The left side of the above formula (1) is represented by R AM 2 It represents the left side of the above formula (2).

[0034] <5>

[0035] The inorganic solid electrolyte-containing composition according to any one of <1> to <4>, wherein

[0036] The dispersion medium comprises at least one selected from ester compounds, ketone compounds, ether compounds, alcohol compounds, amide compounds, amine compounds and nitrile compounds, and the molecular weight of the polymer binder is 10,000 to 700,000.

[0037] or,

[0038] The dispersion medium includes at least one selected from aromatic compounds and aliphatic compounds, and the molecular weight of the polymer binder is 70,000 to 1,000,000.

[0039] <6>

[0040] The inorganic solid electrolyte-containing composition according to any one of <1> to <5>, wherein

[0041] The difference between the SP value of the dispersion medium and the SP value of the polymer binder is 3 or less.

[0042] <7>

[0043] The inorganic solid electrolyte-containing composition according to any one of <1> to <6>, wherein

[0044] The polymer forming the polymer binder includes a constituent component having a functional group selected from the following functional group group (a).

[0045] <Functional group (a)>

[0046] Hydroxyl, amino, carboxyl, sulfo, phosphoric acid, phosphonic acid, sulfanyl, ether bond, imino, ester bond, amide bond, carbamate bond, urea bond, heterocyclic group, aromatic group, carboxylic anhydride group, fluoroalkyl group

[0047] <8>

[0048] A sheet for an all-solid-state secondary battery, comprising a layer comprising the inorganic solid electrolyte composition described in any one of <1> to <7>.

[0049] <9>

[0050] An all-solid-state secondary battery comprises a positive electrode active material layer, a solid electrolyte layer and a negative electrode active material layer in sequence, wherein:

[0051] At least one of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer includes a layer composed of the inorganic solid electrolyte composition described in any one of <1> to <7>.

[0052] <10>

[0053] A method for producing a sheet for an all-solid-state secondary battery, comprising the step of forming a film containing the inorganic solid electrolyte composition described in any one of <1> to <7>.

[0054] <11>

[0055] A method for producing an all-solid-state secondary battery, comprising the step of assembling the all-solid-state secondary battery sheet obtained by the production method described in <10> into the all-solid-state secondary battery.

[0056] Effects of the Invention

[0057] The present invention can provide a kind of dispersion characteristics (dispersibility and stability) and coating suitability (surface property and adhesion) containing inorganic solid electrolyte composition excellent, it is by being used as the constituent layer forming material of all-solid-state secondary battery, can realize the containing inorganic solid electrolyte composition of excellent cycle characteristics. In addition, the present invention can provide a kind of all-solid-state secondary battery sheet material and all-solid-state secondary battery with the layer consisting of the containing inorganic solid electrolyte composition. In addition, the present invention can provide a kind of all-solid-state secondary battery sheet material and all-solid-state secondary battery manufacturing method using the containing inorganic solid electrolyte composition. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is a longitudinal sectional view schematically showing an all-solid-state secondary battery according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0059] In the present invention, the numerical range represented by “to” means a range including the numerical values ​​described before and after “to” as the lower limit and the upper limit.

[0060] In the present invention, the term "compound" (for example, when referring to a compound with "compound" at the end) includes not only the compound itself but also its salts and ions. It also includes derivatives in which some parts are modified, such as by introducing substituents, within a range that does not impair the effects of the present invention.

[0061] In the present invention, (meth)acrylic acid refers to one or both of acrylic acid and methacrylic acid. The same applies to (meth)acrylate.

[0062] In the present invention, when a substituent, a linking group, etc. (hereinafter referred to as a substituent, etc.) is not clearly stated as substituted or unsubstituted, it means that the group may also have an appropriate substituent. Therefore, in the present invention, even when simply stated as a YYY group, the YYY group includes not only a form without a substituent but also a form with a substituent. This also has the same meaning for compounds that are not clearly stated as substituted or unsubstituted. As a preferred substituent, for example, the substituent Z described below can be cited.

[0063] In the present invention, when there are multiple substituents, etc. represented by specific symbols, or when multiple substituents, etc. are specified simultaneously or selectively, it means that the substituents, etc. may be the same or different from each other. Furthermore, even if not otherwise specified, when multiple substituents, etc. are adjacent, it means that they may be linked or fused to each other to form a ring.

[0064] In the present invention, the term "polymer" refers to a polymer, which is synonymous with a high molecular compound. Furthermore, the term "polymer binder" refers to a binder composed of a polymer, including the polymer itself and a binder containing a polymer.

[0065] [Inorganic solid electrolyte composition]

[0066] The inorganic solid electrolyte-containing composition of the present invention is an inorganic solid electrolyte-containing composition for an all-solid-state secondary battery, comprising an inorganic solid electrolyte having ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, a polymer binder, and a dispersion medium. The polymer binder contained in the inorganic solid electrolyte-containing composition satisfies the relationship defined by the following formula (1) with respect to surface energy between the inorganic solid electrolyte and exhibits an adsorption rate of 50% or less on the inorganic solid electrolyte.

[0067] That is, the inorganic solid electrolyte-containing composition of the present invention only needs to contain the aforementioned polymer binder, and its inclusion state is not particularly limited. For example, in the inorganic solid electrolyte-containing composition, the polymer binder may or may not be adsorbed on the inorganic solid electrolyte. If adsorbed, the degree of adsorption can be within the range of the adsorption rate described below.

[0068] The polymer binder functions as a binder that bonds solid particles such as an inorganic solid electrolyte (and, in addition, active materials and conductive additives that can coexist) to each other (e.g., inorganic solid electrolytes to each other, inorganic solid electrolytes and active materials, and active materials to each other) in a layer at least formed by the inorganic solid electrolyte composition. In addition, it also functions as a binder that bonds the current collector and the solid particles. In the inorganic solid electrolyte composition, the polymer binder may or may not have the function of bonding the solid particles to each other.

[0069] The inorganic solid electrolyte composition of the present invention is preferably a slurry in which an inorganic solid electrolyte is dispersed in a dispersion medium. At this time, the above-mentioned polymer binder has the function of dispersing solid particles in the dispersion medium by being adsorbed on solid particles such as the inorganic solid electrolyte or between solid particles. Thus, the dispersion characteristics and coating suitability of the inorganic solid electrolyte composition can be improved. Here, the adsorption of solid particles by the polymer binder includes not only physical adsorption but also chemical adsorption (adsorption by forming chemical bonds, adsorption by electron donation, etc.). In addition, when the above-mentioned polymer binder (in a solid state) is dispersed in the dispersion medium, a part of it can be dissolved in the dispersion medium without damaging the effect of the present invention.

[0070] The inorganic solid electrolyte composition of the present invention has excellent dispersion properties (dispersibility and dispersion stability) and coating suitability (surface properties and adhesion). By using the inorganic solid electrolyte composition as a constituent layer forming material, it is possible to realize an all-solid-state secondary battery sheet having a constituent layer with a flat surface and excellent surface properties and excellent adhesion between solid particles, and an all-solid-state secondary battery with excellent cycle characteristics.

[0071] In the embodiment in which the active material layer formed on the current collector is formed from the inorganic solid electrolyte-containing composition of the present invention, strong adhesion between the current collector and the active material layer can be achieved, and the cycle characteristics can be further improved.

[0072] The detailed reason is not clear, but it is believed to be as follows.

[0073] That is, the dispersion component and polar component of the surface energy between the inorganic solid electrolyte and the polymer binder satisfy the relationship defined by the formula (1) described below, and the polymer binder exhibits an adsorption rate of 50% or less for the inorganic solid electrolyte. In the inorganic solid electrolyte-containing composition, the polymer binder penetrates between the inorganic solid electrolyte particles close to the surface energy, without excessively adsorbing the inorganic solid electrolyte, thereby forming an intercalated state and improving dispersibility. Furthermore, it is believed that the reaggregation or precipitation of the inorganic solid electrolyte can be suppressed not only after the preparation of the inorganic solid electrolyte-containing composition but also after the passage of time, and a high degree of dispersion can be stably maintained (excellent dispersion stability).

[0074] If the inorganic solid electrolyte composition containing the present invention showing this excellent dispersion characteristic is used to form a constituent layer, then even when the constituent layer is film-formed (for example, when applying the inorganic solid electrolyte composition containing the inorganic solid electrolyte composition and when drying), it is possible to suppress the recondensation or sedimentation of the inorganic solid electrolyte. Thus, it is possible to suppress the deviation of the contact state of the inorganic solid electrolyte in the constituent layer. In particular, when containing an inorganic solid electrolyte composition containing active material, it is believed that specific particles such as active material are not easy to be unevenly distributed in the constituent layer (solid particles are uniformly configured in the constituent layer). Therefore, it is possible to suppress the generation or amplification of the pores caused by charge and discharge, and contribute to the improvement of the cycle characteristics of all-solid-state secondary batteries.

[0075] In addition, the inorganic solid electrolyte composition containing the present invention can effectively weaken the interaction between the particles of inorganic solid electrolyte, when containing the film forming of inorganic solid electrolyte composition, except being able to improve dispersion characteristics, film making can also be made to show suitable viscosity (fluidity).As a result, the inorganic solid electrolyte composition containing after coating is appropriately flowed (leveling), can suppress the generation (excellent surface of coating surface) of the concavoconvexity of the ups and downs caused by insufficient flow or excessive flow, and the interface contact state of solid particles is good (high adhesion) and fits firmly.Therefore, in the present invention, the solid component concentration containing inorganic solid electrolyte composition can be set as higher than in the past, it is possible to realize the dispersion characteristics and coating suitability of above-mentioned excellence.

[0076] When using this dispersion characteristic and coating suitability containing inorganic solid electrolyte composition to form a constituent layer, it is possible to suppress the generation of pores due to the improvement of the dispersion characteristic, while the adhesion of solid particles to each other, or even solid particles and substrate (collector) is strengthened, and it is possible to suppress current concentration (deterioration of solid particles) to the steep convex portion of the constituent layer surface. Therefore, it is believed that even if repeated charge and discharge will not lead to a significant reduction in battery characteristics, an all-solid-state secondary battery with excellent cycle characteristics can be achieved.

[0077] The solid content concentration of the inorganic solid electrolyte-containing composition is not particularly limited and can be appropriately set. For example, it can be 20 to 80% by mass, preferably 30 to 70% by mass, and more preferably 40 to 60% by mass.

[0078] In the present invention, by making a composition containing a polymer binder, an inorganic solid electrolyte and a dispersion medium that satisfies the relationship specified by the formula (1) described later and exhibits an adsorption rate of 50% or less relative to the inorganic solid electrolyte, the dispersion characteristics and coating suitability can be improved. Therefore, as a composition containing an inorganic solid electrolyte, a high-concentration composition in which the solid content concentration is set to a higher concentration than before can be used. For example, the lower limit of the solid content concentration of the high-concentration composition can be set to 50% or more by mass. The upper limit is less than 100% by mass, for example, it can be set to 90% or less by mass, preferably 85% or less by mass, and more preferably 80% or less by mass.

[0079] When the active material layer is formed by the inorganic solid electrolyte composition containing the present invention, as described above, a constituent layer is formed while maintaining the dispersed state of the height (uniform) just after preparation. Therefore, it is believed that by the solid particles preferentially precipitated, the contact (fit) between the polymer binder and the collector surface will not be hindered, and the polymer binder can contact (fit) with the collector surface in a state dispersed with the solid particles. Thus, the all-solid-state secondary battery electrode sheet for forming the active material layer by the inorganic solid electrolyte composition containing the present invention on the collector can achieve the firm adhesion of the collector and the active material. Moreover, the all-solid-state secondary battery for forming the active material layer by the inorganic solid electrolyte composition containing the present invention on the collector shows the firm adhesion of the collector and the active material and can achieve a further improvement in cycle characteristics and conductivity.

[0080] The inorganic solid electrolyte-containing composition of the present invention can be preferably used as a sheet for an all-solid-state secondary battery (including an electrode sheet for an all-solid-state secondary battery) or a forming material for a solid electrolyte layer or active material layer of an all-solid-state secondary battery (a constituent layer forming material). In particular, the content of the inorganic solid electrolyte in the solid component is high, and it can be preferably used as a forming material for a solid electrolyte sheet or solid electrolyte layer for an all-solid-state secondary battery, and in this manner, high cycle characteristics can also be achieved.

[0081] The viscosity of the inorganic solid electrolyte-containing composition of the present invention at 25°C (room temperature) is not particularly limited. From the perspective of improving dispersion characteristics and coating suitability, the viscosity at 25°C is preferably 200 to 15,000 cP, more preferably 200 to 8,000 cP, and even more preferably 400 to 6,000 cP.

[0082] The viscosity of the inorganic solid electrolyte-containing composition can be appropriately set by, for example, changing or adjusting the solid content concentration of the inorganic solid electrolyte-containing composition, the type and content of solid particles or polymer binder, the type of dispersion medium, and further the dispersion conditions.

[0083] (Method for measuring slurry viscosity)

[0084] The viscosity of the inorganic solid electrolyte-containing composition is a value measured by the following method.

[0085] Specifically, an E-type viscometer (TV-35, manufactured by Toki Sangyo Co., Ltd.) and a standard conical rotor (1 "34' × R24) were used. 1.1 mL of the sample (including the inorganic solid electrolyte composition) was added to a sample cup adjusted to 25°C and the sample cup was placed in the main body. After maintaining the temperature for 5 minutes until it became constant, the measurement range was set to "U" and the value measured 1 minute after the rotation was started at a shear rate of 10 / s (rotation speed of 2.5 rpm) was set as the viscosity.

[0086] The inorganic solid electrolyte composition of the present invention is preferably a non-aqueous composition. In the present invention, the non-aqueous composition, in addition to including a mode that does not contain water, also includes a mode in which the water content is preferably 500 ppm or less. In the non-aqueous composition, the water content is more preferably 200 ppm or less, further preferably 100 ppm or less, and particularly preferably 50 ppm or less. If the inorganic solid electrolyte composition is a non-aqueous composition, the degradation of the inorganic solid electrolyte can be suppressed. The water content represents the amount of water contained in the inorganic solid electrolyte composition (to the mass ratio of the inorganic solid electrolyte composition), specifically, it is a value obtained by filtering with a 0.02 μm membrane filter and measuring using Karl Fischer titration.

[0087] The inorganic solid electrolyte-containing composition of the present invention includes, in addition to the inorganic solid electrolyte, the polymer binder, and the dispersion medium, an active material, a conductive additive, and the like (a composition of this embodiment is referred to as an electrode composition).

[0088] Hereinafter, components contained in and components that may be contained in the inorganic solid electrolyte-containing composition of the present invention will be described.

[0089] Inorganic solid electrolytes

[0090] The inorganic solid electrolyte-containing composition of the present invention contains an inorganic solid electrolyte (when in a particulate form, also referred to as inorganic solid electrolyte particles).

[0091] In the present invention, an inorganic solid electrolyte refers to an inorganic solid electrolyte, and a solid electrolyte refers to a solid electrolyte that enables ions to move within it. Considering that the inorganic solid electrolyte does not contain an organic substance as the main ion conductive material, it is clearly distinguished from an organic solid electrolyte (a polymer electrolyte represented by polyethylene oxide (PEO) or the like, an organic electrolyte salt represented by lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) or the like). In addition, since the inorganic solid electrolyte is solid in a stable state, it is usually not dissociated or freed into cations and anions. In this regard, it is clearly distinguished from an inorganic electrolyte salt (LiPF6, LiBF4, lithium bis(fluorosulfonyl)imide (LiFSI), LiCl, etc.) that dissociates or frees into cations and anions in an electrolyte or polymer. As long as the inorganic solid electrolyte has the ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, it is not particularly limited and usually does not have electronic conductivity. When the all-solid-state secondary battery of the present invention is a lithium ion battery, the inorganic solid electrolyte preferably has ion conductivity for lithium ions.

[0092] The inorganic solid electrolyte can be appropriately selected from solid electrolyte materials commonly used in all-solid-state secondary batteries. For example, examples of the inorganic solid electrolyte include (i) sulfide-based inorganic solid electrolytes, (ii) oxide-based inorganic solid electrolytes, (iii) halide-based inorganic solid electrolytes, and (iv) hydride-based inorganic solid electrolytes. From the perspective of forming a better interface between the active material and the inorganic solid electrolyte, sulfide-based inorganic solid electrolytes are preferred.

[0093] (i) Sulfide-based inorganic solid electrolytes

[0094] Preferably, the sulfide-based inorganic solid electrolyte is a compound having the ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table and electronic insulation. Preferably, the sulfide-based inorganic solid electrolyte contains at least Li, S, and P as elements and has lithium ion conductivity, but may contain other elements in addition to Li, S, and P depending on the purpose or circumstances.

[0095] Examples of the sulfide-based inorganic solid electrolyte include lithium ion conductive inorganic solid electrolytes having a composition represented by the following formula (S1).

[0096] L a1 M b1 P c1 S d1 A e1 (S1)

[0097] In the formula, L represents an element selected from Li, Na and K, preferably Li. 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 represent the composition ratio of each element, and a1:b1:c1:d1:e1 satisfies 1-12:0-5:1:2-12:0-10. a1 is preferably 1-9, more preferably 1.5-7.5. b1 is preferably 0-3, more preferably 0-1. d1 is preferably 2.5-10, more preferably 3.0-8.5. e1 is preferably 0-5, more preferably 0-3.

[0098] As described below, 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.

[0099] Sulfide-based inorganic solid electrolytes may be amorphous (glass), crystallized (glass-ceramic), or only partially crystallized. For example, Li-PS-based glass containing Li, P, and S or Li-PS-based glass-ceramic containing Li, P, and S can be used.

[0100] Sulfide-based inorganic solid electrolytes can be manufactured by reacting at least two or more raw materials, for example, lithium sulfide (Li2S), phosphorus sulfide (for example, phosphorus pentasulfide (P2S5)), elemental phosphorus, elemental sulfur, sodium sulfide, hydrogen sulfide, lithium halide (for example, LiI, LiBr, LiCl) and sulfides of the elements represented by M above (for example, SiS2, SnS, GeS2).

[0101] The ratio of Li2S to P2S5 in the Li-PS glass and Li-PS glass ceramics is preferably 60:40 to 90:10, more preferably 68:32 to 78:22, in terms of the molar ratio of Li2S:P2S5. By setting the ratio of Li2S to P2S5 within this range, the lithium ion conductivity can be improved. Specifically, the lithium ion conductivity can be preferably set to 1×10 -4 S / cm or more, more preferably 1×10 -3 S / cm or more. Although there is no specific upper limit, it is actually 1×10 -1 S / cm or less.

[0102] As specific examples of sulfide-based inorganic solid electrolytes, combinations of raw materials are shown below. For example, Li2S-P2S5, Li2S-P2S5-LiCl, Li2S-P2S5-H2S, Li2S-P2S5-H2S-LiCl, Li2S-LiI-P2S5, Li2S-LiI-Li2O-P2S5, Li2S-LiBr-P2S5, Li2S-Li2O-P2S5, Li2S-Li3PO4-P2S5, Li2S-P2S5-P2O5, Li2S-P2S5-SiS2, Li2S-P2S5-SiS2-LiCl, Li2S-P2S5-SnS, Li2S-P2S5-Al2 S3, Li2S-GeS2, Li2S-GeS2-ZnS, Li2S-Ga2S3, Li2S-GeS2-Ga2S3, Li2S-GeS2-P2S5, Li2S-GeS2-Sb2S5, Li2S-GeS2-Al2S3, Li2S-SiS2, Li2S-Al2S3, Li2S-SiS2-Al2S3, Li2S-SiS2-P2S5, Li2S-SiS2-P2S5-LiI, Li2S-SiS2-LiI, Li2S-SiS2-Li4SiO4, Li2S-SiS2-Li3PO4, Li 10 GeP2S 12 etc. The mixing ratio of the raw materials is not limited. Examples of methods for synthesizing sulfide-based inorganic solid electrolyte materials using this raw material composition include amorphization. Examples of amorphization methods include mechanical polishing, solution processing, and melt quenching. The ability to process at room temperature simplifies the manufacturing process.

[0103] (ii) Oxide-based inorganic solid electrolytes

[0104] The oxide-based inorganic solid electrolyte is preferably a compound containing oxygen atoms, having ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and having electron insulating properties.

[0105] The ion conductivity of the oxide-based inorganic solid electrolyte is preferably 1×10 -6 S / cm or more, more preferably 5×10 -6 S / cm or more, particularly preferably 1×10 -5 S / cm or more. Although there is no particular upper limit, it is actually 1×10 -1 S / cm or less.

[0106] As a specific example of the compound, for example, Li xa La yaTiO3〔xa satisfies 0.3≤xa≤0.7, ya satisfies 0.3≤ya≤0.7.〕(LLT);Li xb La yb Zr zb M bb mb O nb (M bb is one or more elements selected from the group consisting of 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, and nb satisfies 5≤nb≤20. ); Li xc B yc M cc zc O nc (M cc is one or more elements selected from C, S, Al, Si, Ga, Ge, In, and Sn. xc satisfies 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 O nd (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 greater than or equal to 0 and less than or equal to 0.1, M ee Represents a divalent metal atom. ee represents a halogen atom or a combination of two or more halogen atoms. ); 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.) Li3BO3; Li3BO3-Li2SO4; Li2O-B2O3-P2O5; Li2O-SiO2; Li6BaLa2Ta2O 12 ;Li3PO (4-3 / 2w) N w(w satisfies w<1); Li with LISICON (Lithium super ionic conductor) type crystal structure 3.5 Zn 0.25 GeO4; La with perovskite crystal structure 0.55 Li 0.35 TiO3; LiTi2P3O with NASICON (Natrium super ionic conductor) crystal structure 12 ;Li 1+xh+yh (Al, Ga) xh (Ti, Ge) 2-xh Si yh P 3-yh O 12 (xh satisfies 0≤xh≤1, yh satisfies 0≤yh≤1.); Li7La3Zr2O with garnet crystal structure 12 (LLZ) et al.

[0107] Furthermore, phosphorus compounds containing Li, P, and O are also preferred. Examples thereof include lithium phosphate (Li3PO4); LiPON in which a portion of the oxygen in lithium phosphate is substituted with nitrogen; and LiPOD. 1 (D 1 Preferably, it is one or more elements selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Ag, Ta, W, Pt and Au. ) etc.

[0108] In addition, LiA can also be preferably used 1 ON(A 1 is one or more elements selected from Si, B, Ge, Al, C and Ga. ) etc.

[0109] (iii) Halide-based inorganic solid electrolytes

[0110] The halide-based inorganic solid electrolyte is preferably a compound containing halogen atoms, having ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and having electron insulating properties.

[0111] The halide-based inorganic solid electrolyte is not particularly limited, and examples thereof include LiCl, LiBr, LiI, and compounds such as Li3YBr6 and Li3YCl6 described in ADVANCED MATERIALS, 2018, 30, 1803075. Among them, Li3YBr6 and Li3YCl6 are preferred.

[0112] (iv) Hydride-based inorganic solid electrolytes

[0113] The hydride-based inorganic solid electrolyte is preferably a compound containing hydrogen atoms, having ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and having electron insulating properties.

[0114] The hydride-based inorganic solid electrolyte is not particularly limited, and examples thereof include LiBH 4 , Li 4 (BH 4 ) 3 I, and 3LiBH 4 —LiCl.

[0115] The inorganic solid electrolyte is preferably in the form of particles. The particle size (volume average particle size) of the inorganic solid electrolyte is not particularly limited, but is preferably 0.01 μm or greater, more preferably 0.1 μm or greater. The upper limit is preferably 100 μm or less, more preferably 50 μm or less.

[0116] The particle size of the inorganic solid electrolyte is determined by the following steps. In a 20 mL sample bottle, the inorganic solid electrolyte particles are diluted with water (heptane in the case of a substance unstable to water) to prepare a 1% dispersion. The diluted dispersion sample is irradiated with 1 kHz ultrasound for 10 minutes and then used immediately in the test. Using this dispersion sample, a laser diffraction / scattering particle size distribution analyzer LA-920 (trade name, manufactured by HORIBA, Ltd.) is used and 50 data acquisitions are performed using a quartz cell for measurement at a temperature of 25°C to obtain the volume average particle size. For other detailed conditions, please refer to the description in JIS Z8828:2013 "Particle Size Analysis-Dynamic Light Scattering Method" as needed. Five samples are made for each level and the average value is adopted.

[0117] The inorganic solid electrolyte contained in the inorganic solid electrolyte-containing composition may be one kind or two or more kinds.

[0118] When a solid electrolyte layer is formed, the solid electrolyte layer has a surface area (cm 2 The mass (mg) (weight per unit area) of the inorganic solid electrolyte is not particularly limited. It can be appropriately determined according to the designed battery capacity, for example, it can be set to 1 to 100 mg / cm 2 .

[0119] When the inorganic solid electrolyte-containing composition contains an active material described later, the total amount of the active material and the inorganic solid electrolyte is preferably within the above-mentioned range regarding the weight per unit area of ​​the inorganic solid electrolyte.

[0120] The content of the inorganic solid electrolyte in the inorganic solid electrolyte-containing composition is not particularly limited. In terms of dispersion characteristics and coating suitability, the content is preferably 50% by mass or more, more preferably 70% by mass or more, and particularly preferably 90% by mass or more, out of 100% by mass of the solid content. As an upper limit, from the same viewpoint, it is preferably 99.9% by mass or less, more preferably 99.5% by mass or less, and particularly preferably 99% by mass or less.

[0121] However, when the inorganic solid electrolyte-containing composition contains an active material described later, the total content of the inorganic solid electrolyte in the inorganic solid electrolyte-containing composition is preferably within the above range.

[0122] In the present invention, the solid content refers to the components that do not disappear when the inorganic solid electrolyte composition is dried at 150°C for 6 hours under a nitrogen atmosphere at a pressure of 1 mmHg. Typically, it refers to the components other than the dispersion medium described below.

[0123] <Polymer Binder>

[0124] The inorganic solid electrolyte-containing composition of the present invention contains a polymer binder that exhibits an adsorption rate of 50% or less relative to the inorganic solid electrolyte in the dispersion medium contained in the composition, and the polymer binder satisfies the relationship specified by the following formula (1) with respect to surface energy between the polymer binder and the inorganic solid electrolyte.

[0125] The polymer binder is used in combination with solid particles such as an inorganic solid electrolyte in the inorganic solid electrolyte-containing composition of the present invention to improve the dispersion characteristics and coating suitability of the inorganic solid electrolyte-containing composition (slurry).

[0126] (Adsorption rate)

[0127] In the present invention, the adsorption rate (%) of the polymer binder is a value measured using the inorganic solid electrolyte and a specific dispersion medium contained in the inorganic solid electrolyte composition, and is an indicator showing the degree of adsorption of the polymer binder in the dispersion medium to the inorganic solid electrolyte. Here, adsorption of the polymer binder to the inorganic solid electrolyte includes not only physical adsorption but also chemical adsorption (adsorption through chemical bond formation, adsorption through electron transfer, etc.).

[0128] When the inorganic solid electrolyte-containing composition contains multiple inorganic solid electrolytes, the adsorption rate is measured using an inorganic solid electrolyte having the same composition (type and content) as the inorganic solid electrolyte in the inorganic solid electrolyte-containing composition. When the inorganic solid electrolyte-containing composition contains multiple specific dispersion media, the adsorption rate is similarly measured using a dispersion medium having the same composition (type and content) as the specific dispersion medium in the inorganic solid electrolyte-containing composition.

[0129] When the inorganic solid electrolyte composition contains a plurality of polymer binders, the adsorption rate of each specific polymer binder in the inorganic solid electrolyte composition is measured, and any polymer binder may satisfy the relationship between the above adsorption rate and the formula (1) described below.

[0130] In the present invention, the adsorption rate of the polymer binder is a value calculated by the method described in Examples.

[0131] The adsorption rate of the polymer binder is 50% or less. If the polymer binder shows the above-mentioned adsorption rate, it is possible to suppress excessive adsorption of the inorganic solid electrolyte and improve the dispersion characteristics and coating suitability of the inorganic solid electrolyte composition. From the perspective of being able to take into account both dispersion characteristics and coating suitability at a higher level, the adsorption rate is preferably 40% or less, more preferably 30% or less, further preferably less than 20%, and particularly preferably 15% or less. Furthermore, it is also preferably set to 10% or less. On the other hand, the lower limit of the adsorption rate is not particularly limited and can also be set to 0%. From the perspective of dispersion characteristics and coating suitability, the lower limit of the adsorption rate is preferably small. On the other hand, from the perspective of improving the adhesion of the inorganic solid electrolyte, it is preferably 3% or more, more preferably 5% or more, and further preferably 7% or more.

[0132] In the present invention, the adsorption rate of the inorganic solid electrolyte can be appropriately set by the properties of the polymer forming the polymer binder (such as the mass average molecular weight), the type or content of the functional groups possessed by the polymer, the form of the polymer binder (the amount dissolved in the dispersion medium), etc.

[0133] The polymer binder may be soluble (soluble binder) or insoluble (insoluble binder) in the dispersion medium contained in the inorganic solid electrolyte composition, but soluble binders that dissolve in the dispersion medium are preferred. When two or more polymer binders are contained, it is preferred that at least one polymer binder be soluble, but all polymer binders may be soluble.

[0134] In the present invention, "a polymer binder dissolved in a dispersion medium" means that the polymer binder dissolves in the dispersion medium containing the inorganic solid electrolyte composition, for example, a solubility of 10% by mass or greater in a solubility measurement. Conversely, "a non-dissolving type binder" means that the polymer binder does not dissolve in the dispersion medium, and a solubility of less than 10% by mass in a solubility measurement. The solubility measurement method is as follows.

[0135] Specifically, a predetermined amount of the polymer binder to be measured is weighed into a glass bottle. 100 g of a dispersion medium of the same type as that contained in the inorganic solid electrolyte composition is added to the mixture. The mixture is then stirred at 80 rpm on a mixing rotor at 25°C for 24 hours. The transmittance of the resulting mixed solution after 24 hours of stirring is measured under the following conditions. This test (transmittance measurement) is performed by varying the amount of polymer binder dissolved (the predetermined amount described above), with the upper limit concentration X (mass %) at which the transmittance reaches 99.8% being defined as the solubility of the polymer binder in the dispersion medium.

[0136] <Transmittance measurement conditions>

[0137] Dynamic light scattering (DLS) measurement

[0138] Device: DLS measuring device DLS-8000 manufactured by Otsuka Electronics Co., Ltd.

[0139] Laser wavelength, output: 488nm / 100mW

[0140] Sample cell: NMR tube

[0141] When the inorganic solid electrolyte composition of the present invention contains an active material described below (when an active material layer is formed from the inorganic solid electrolyte composition), the adsorption rate of the polymer binder on the active material is not particularly limited. From the perspective of enhancing the dispersion characteristics and coating suitability of the inorganic solid electrolyte composition and the binding properties of the solid particles, it is preferably 90% or less, more preferably 0.1 to 50%, and even more preferably 1 to 10%. In the present invention, the adsorption rate of the polymer binder on the active material is a value measured using the active material contained in the inorganic solid electrolyte composition and a dispersion medium, and is an indicator showing the degree of adsorption of the polymer binder in the dispersion medium to the active material. Here, adsorption of the active material by the polymer binder includes not only physical adsorption but also chemical adsorption (adsorption through chemical bond formation, adsorption through electron transfer, etc.).

[0142] When the inorganic solid electrolyte composition contains multiple active materials, contains multiple specific dispersion media, and further uses multiple polymer binders, the adsorption rate of the polymer binder on the inorganic solid electrolyte is the same as that described above. In the present invention, the adsorption rate of the polymer binder on the active material is the same as that calculated in the [Determination of the Adsorption Rate of the Binder on the Inorganic Solid Electrolyte] method described in the Examples, except that the active material is used instead of the inorganic solid electrolyte. In the present invention, the adsorption rate on the active material can be appropriately set in the same manner as the adsorption rate on the inorganic solid electrolyte.

[0143] (Dispersive and polar components of surface energy)

[0144] In the present invention, the polymer binder and the inorganic solid electrolyte satisfy the relationship defined by the following formula (1) with respect to surface energy.

[0145] (Xse-Xba) 2 +(Yse-Yba) 2 ≤R 2 Formula (1)

[0146] Wherein, Xse represents the dispersive component of the surface energy of the inorganic solid electrolyte, and Yse represents the polar component of the surface energy of the inorganic solid electrolyte. Xba represents the dispersive component of the surface energy of the polymer binder, and Yba represents the polar component of the surface energy of the polymer binder. R is 20. Furthermore, the units of Xse, Xba, Yse, Yba, and R are all mN / m.

[0147] The left side of the above formula (1) represents the sum of the square of the difference between the dispersion component and the polar component of the surface energy of the polymer binder and the inorganic solid electrolyte. The smaller the sum, the higher the affinity between the polymer binder and the inorganic solid electrolyte. In the present invention, it can be inferred that by satisfying the relationship specified by the above formula (1), that is, the above sum is R 2 (=400) or less, the polymer binder and the inorganic solid electrolyte show high affinity. Through the dispersion process when preparing the inorganic solid electrolyte composition of the present invention, the polymer binder can easily enter between the inorganic solid electrolytes, inhibit the agglomeration of the inorganic solid electrolyte, and improve the dispersion characteristics and coating suitability of the inorganic solid electrolyte in the inorganic solid electrolyte composition.

[0148] When the inorganic solid electrolyte-containing composition contains multiple inorganic solid electrolytes, the dispersion component and polar component of the surface energy of the inorganic solid electrolyte having the same composition (type and content) as the inorganic solid electrolyte in the inorganic solid electrolyte-containing composition are measured. When the inorganic solid electrolyte-containing composition contains multiple specific polymer binders, the dispersion component and polar component of the surface energy of each specific polymer binder in the inorganic solid electrolyte-containing composition are measured, and any one of the polymer binders satisfies the above-mentioned adsorption rate and the relationship defined by the above-mentioned formula (1).

[0149] In the present invention, the dispersion component and polar component of the surface energy of each of the polymer binder and the inorganic solid electrolyte are set to values ​​calculated by the method described in the Examples.

[0150] From the viewpoint of achieving both dispersion characteristics and coating suitability at a higher level, R in the above formula (1) is preferably 18 or less, more preferably 15 or less, further preferably 10 or less, and particularly preferably 7 or less. On the other hand, the lower limit of R in the above formula (1) is not particularly limited and can be 0. From the viewpoint of cycle characteristics, it is preferably 0.3 or more, more preferably 0.6 or more, and even more preferably 0.9 or more.

[0151] In the above formula (1), the upper limit of R is always 0 to the first decimal place. That is, R = 20 means R = 20.0. The calculated value on the left side of the above formula (1) is rounded to the second decimal place.

[0152] In the present invention, the dispersion component and polar component of the surface energy of the polymer binder can be appropriately set according to the constituent components of the polymer forming the polymer binder, the type and content of functional groups possessed by the polymer, the molecular weight, and the like.

[0153] When the inorganic solid electrolyte-containing composition of the present invention contains an active material described later, the active material and the polymer binder preferably satisfy the relationship defined by the following formula (2) with respect to surface energy.

[0154] (Xam-Xba) 2 +(Yam-Yba) 2 ≤r 2 Formula (2)

[0155] Wherein, Xam represents the dispersive component of the surface energy of the active material, and Yam represents the polar component of the surface energy of the active material. Xba represents the dispersive component of the surface energy of the polymer binder, and Yba represents the polar component of the surface energy of the polymer binder. r is 30. The units of Xam, Xba, Yam, Yba, and r are all mN / m.

[0156] The left side of the above formula (2) represents the sum of the square of the difference between the dispersion component and the polar component of the surface energy of the active material and the polymer binder. The smaller the sum, the higher the affinity between the active material and the polymer binder. In the present invention, it is considered that by satisfying the relationship specified by the above formula (2), that is, the above sum is r 2 (=900) or less, the active material and the polymer binder show high affinity. Through the dispersion process when preparing the inorganic solid electrolyte composition of the present invention, the polymer binder can easily enter between the active materials, inhibit the agglomeration of the active materials, and improve the dispersion characteristics and coating suitability of the inorganic solid electrolyte composition.

[0157] When the inorganic solid electrolyte composition contains multiple active materials, the dispersion component and polar component of the surface energy of the inorganic solid electrolyte having the same composition (type and content) as the active materials in the inorganic solid electrolyte composition are measured. When the inorganic solid electrolyte composition contains multiple specific polymer binders, the dispersion component and polar component of the surface energy of each specific polymer binder in the inorganic solid electrolyte composition are measured. Any polymer binder satisfies the above-mentioned adsorption rate and the relationship defined by the above-mentioned formulas (1) and (2).

[0158] In the present invention, the dispersion component and polar component of the surface energy of the active material are set to values ​​calculated by the method described in the Examples.

[0159] From the viewpoint of achieving both dispersion characteristics and coating suitability at a higher level, r in the above formula (2) is preferably 27 or less, more preferably 26 or less, and even more preferably 25 or less. On the other hand, the lower limit of r in the above formula (2) is not particularly limited and can be 0. From the viewpoint of cycle characteristics, it is preferably 0.5 or more, more preferably 1.0 or more, and even more preferably 1.5 or more.

[0160] In addition, the upper limit of r in the above formula (2) is always 0 to the first decimal place. That is, r = 30 means R = 30.0. Furthermore, the calculated value on the left side of the above formula (2) is rounded to the second decimal place. Similarly, for the following formulas (3) and (4), the value on the right side is 0 to the first decimal place, and the calculated value on the left side is rounded to the second decimal place.

[0161] Furthermore, when the inorganic solid electrolyte-containing composition of the present invention contains an active material described later, it is preferred that the inorganic solid electrolyte, the polymer binder, and the active material satisfy the relationship defined by the following formula (3) with respect to surface energy.

[0162] R SE +R AM ≤30 Formula (3)

[0163] Where R SE 2 The left side of the above formula (1) is represented by R AM 2 represents the left side of the above formula (2). That is, R SE represents {(Xse-Xba) 2 +(Yse-Yba) 2} 0.5 , R AM Indicates {(Xam-Xba) 2 +(Yam-Yba) 2} 0.5 .

[0164] The left side of the above formula (3) represents the sum of the 0.5 power of the left side of the above formula (1) and the 0.5 power of the left side of the above formula (2). The smaller the sum, the higher the affinity between the inorganic solid electrolyte and the polymer binder and the affinity between the active material and the polymer binder. In the present invention, it is believed that by satisfying the relationship specified by the above formula (3), that is, the above sum is 30 or less, the active material and the inorganic solid electrolyte both show high affinity with the polymer binder. Through the dispersion step when preparing the inorganic solid electrolyte-containing composition of the present invention, the polymer binder easily enters between the inorganic solid electrolyte and the active material, suppressing the aggregation of the inorganic solid electrolyte and the active material, and improving the dispersion characteristics and coating suitability of the inorganic solid electrolyte and the active material in the inorganic solid electrolyte-containing composition.

[0165] When the inorganic solid electrolyte composition contains multiple active materials, the dispersion component and polar component of the surface energy of the inorganic solid electrolyte having the same composition (type and content) as the active materials in the inorganic solid electrolyte composition are measured. When the inorganic solid electrolyte composition contains multiple specific polymer binders, the dispersion component and polar component of the surface energy of each specific polymer binder in the inorganic solid electrolyte composition are measured. Any polymer binder satisfies the above-mentioned adsorption rate and the relationship defined by the above-mentioned formulas (1) to (3).

[0166] From the viewpoint of achieving both dispersion characteristics and coating suitability at a higher level, R in the above formula (3) SE +R AM Preferably, it is 27 or less. On the other hand, R in the above formula (3) SE +R AM The lower limit of is not particularly limited and can be 0. From the viewpoint of cycle characteristics, it is preferably 1.0 or more, more preferably 2.0 or more, and even more preferably 3.0 or more.

[0167] Among the inorganic solid electrolytes and active materials commonly used in all-solid-state secondary batteries, the inorganic solid electrolyte is more likely to aggregate than the active material. Therefore, from the perspective of more effectively improving the dispersion characteristics and coating suitability of the inorganic solid electrolyte-containing composition, it is important to improve the dispersibility of the inorganic solid electrolyte. Therefore, when the inorganic solid electrolyte-containing composition of the present invention contains an active material described later, from the perspective of further improving the dispersion characteristics and coating suitability of the inorganic solid electrolyte-containing composition, it is preferable to satisfy the relationship defined by the following formula (4).

[0168] R AM -R SE ≥-13 Formula (4)

[0169] Where R SE and R AM With R in the above formula (3) SE and R AM Same meaning.

[0170] In the present invention, it is believed that by satisfying the relationship specified by the above-mentioned formula (4), through the dispersion process when preparing the inorganic solid electrolyte composition of the present invention, even when the inorganic solid electrolyte and the active material are present at the same time, the polymer binder can enter between the inorganic solid electrolytes and can effectively inhibit the aggregation of the inorganic solid electrolyte.

[0171] From the viewpoint of achieving both dispersion characteristics and coating suitability at a higher level, R in the above formula (4) AM -R SE It is preferably -9 or greater, more preferably -3 or greater, and even more preferably 0 or greater. On the other hand, R in the above formula (4) AM -R SE The upper limit of is not particularly limited and can be set to 30, but is preferably 25 or less.

[0172] The polymer forming the polymer binder is not particularly limited as long as it satisfies the above-mentioned adsorption rate for the inorganic solid electrolyte, and various polymers can be used.

[0173] From the perspective of dispersion stability, it is preferred that the polymer does not react with the inorganic solid electrolyte during heating during the preparation of the inorganic solid electrolyte-containing composition, the production of the sheet for an all-solid-state secondary battery, or the production of an all-solid-state secondary battery. Specifically, the polymer preferably does not have an ethylenically unsaturated double bond.

[0174] Among these, preferably, a polymer having a polymer chain having a carbon-carbon double bond in the main chain is used.

[0175] When two or more polymer binders are contained, it is preferred that the polymer forming at least one polymer binder has the above-mentioned polymer chain in its main chain. It is also preferred that the polymer forming all polymer binders have the above-mentioned polymer chain in their main chain.

[0176] In the present invention, the main chain of a polymer refers to all other molecular chains that constitute the polymer, including linear molecular chains that can be considered branches or comb-shaped chains relative to the main chain. While this depends on the mass-average molecular weight of the molecular chains that are considered branches or comb-shaped chains, typically the longest chain in the polymer constitutes the main chain. However, terminal groups at the ends of the polymer are not included in the main chain. Furthermore, side chains of a polymer refer to molecular chains other than the main chain, including both short and long molecular chains.

[0177] Examples of polymers having a polymer chain with carbon-carbon double bonds in the main chain include chain polymers such as fluorine-based polymers (fluorinated polymers), hydrocarbon-based polymers, vinyl-based polymers, and (meth)acrylic polymers. The polymerization method of these chain polymers is not particularly limited, and they may be any of block copolymers, alternating copolymers, and random copolymers.

[0178] As the polymer forming the polymer binder, the above-mentioned polymers can be appropriately selected, but a fluorine-based polymer or a (meth)acrylic polymer is preferred, and a (meth)acrylic polymer is more preferred.

[0179] The polymers forming the polymer binder may be one kind or two or more kinds.

[0180] (Constituent having a functional group selected from the functional group group (a))

[0181] The polymer constituting the polymer binder preferably includes a component having a functional group selected from the following functional group group (a). When two or more polymer binders are included, the polymer forming at least one of the polymer binders preferably includes a component having the functional group. It is also preferred that the polymers forming all of the polymer binders include components having the functional group. The component having the functional group has the function of increasing the adsorption rate of the polymer binder to the inorganic solid electrolyte and may be any component forming the polymer.

[0182] The functional group can be incorporated into the main chain of the polymer or into a side chain. When incorporated into a side chain, the functional group can be directly bonded to the main chain or bonded via a linker. The linker is not particularly limited, and examples thereof include the linkers described below.

[0183] In a chain polymer, a component having an ester bond (excluding an ester bond forming a carboxyl group) or an amide bond means a component in which the ester bond or amide bond is not directly bonded to an atom in the main chain constituting the chain polymer or the main chain of a polymer chain incorporated as a branch or comb-shaped chain in the chain polymer (for example, a polymer chain possessed by a macromonomer), and for example, does not include a component derived from an alkyl (meth)acrylate.

[0184] The functional groups possessed by one constituent component may be one type or two or more types. When two or more types are possessed, the functional groups may or may not be bonded to each other.

[0185] <Functional group (a)>

[0186] Hydroxyl group, amino group, carboxyl group, sulfo group, phosphoric acid group, phosphonic acid group, sulfanyl group, ether bond (-O-), imino group (=NR, -NR-), ester bond (-CO-O-), amide bond (-CO-NR-), carbamate bond (-NR-CO-O-), urea bond (-NR-CO-NR-), heterocyclic group, aryl group, carboxylic anhydride group, fluoroalkyl group

[0187] The amino group, sulfo group, phosphoric acid group (phosphoryl group), heterocyclic group, and aryl group contained in the functional group (a) are not particularly limited, and have the same meaning as the corresponding groups of the substituent Z described below. Among them, the number of carbon atoms of the amino group is more preferably 0 to 12, further preferably 0 to 6, and particularly preferably 0 to 2. There is no particular limitation on the phosphonic acid group, and examples thereof include phosphonic acid groups having 0 to 20 carbon atoms. When an amino group, an ether bond, an imino group (-NR-), an ester bond, an amide bond, a carbamate bond, a urea bond, etc. are contained in a ring structure, it is classified as a heterocycle. Hydroxyl, amino group, carboxyl group, sulfo group, phosphoric acid group, phosphonic acid group, and sulfanyl group can form salts.

[0188] A fluoroalkyl group is a group obtained by substituting a fluorine atom for at least one hydrogen atom in an alkyl group or a cycloalkyl group, and preferably has 1 to 20 carbon atoms, more preferably 2 to 15, and even more preferably 3 to 10. The fluorine atoms on the carbon atoms may be substituted for some or all of the hydrogen atoms (perfluoroalkyl group).

[0189] The siloxane group is not particularly limited, and preferably has a siloxane group consisting of -(SiR2-O) n The repeating number n is preferably an integer of 1 to 100, more preferably an integer of 5 to 50, and even more preferably an integer of 10 to 30.

[0190] R in each bond represents a hydrogen atom or a substituent, preferably a hydrogen atom. The substituent is not particularly limited and is selected from the substituent Z described below, preferably an alkyl group.

[0191] There are no particular restrictions on the carboxylic acid anhydride group, and the group includes a group formed by removing one or more hydrogen atoms from a carboxylic acid anhydride (for example, a group represented by the following formula (2a)), and further a constituent formed by copolymerization of a polymerizable carboxylic acid anhydride as a copolymerizable compound (for example, a constituent represented by the following formula (2b)). As a group formed by removing one or more hydrogen atoms from a carboxylic acid anhydride, a group formed by removing one or more hydrogen atoms from a cyclic carboxylic acid anhydride is preferably a group. The carboxylic acid anhydride group derived from a cyclic carboxylic acid anhydride is also equivalent to a heterocyclic group, but is classified as a carboxylic acid anhydride group in the present invention. For example, non-cyclic carboxylic acid anhydrides such as acetic anhydride, propionic anhydride, and benzoic acid rod, cyclic carboxylic acid anhydrides such as maleic anhydride, phthalic anhydride, fumaric acid rod, and succinic anhydride can be cited. There are no particular restrictions on the polymerizable carboxylic acid anhydride, and carboxylic acid anhydrides having an unsaturated bond in the molecule can be cited, preferably polymerizable cyclic carboxylic acid anhydrides. Specifically, maleic anhydride can be cited.

[0192] Examples of the carboxylic anhydride group include a group represented by the following formula (2a) and a constituent represented by the following formula (2b), but the present invention is not limited thereto. In each formula, * represents a bonding position.

[0193] [Chemical Formula 1]

[0194]

[0195] There is no particular limitation on the linking group between the bonding functional group and the main chain, and R of the formula (1-1) described below may be used. 2 The linking groups of the groups having a hydrocarbon group with 4 or more carbon atoms are the same as those of the groups having a hydrocarbon group with 4 or more carbon atoms, except for the particularly preferred linking groups. As the linking group for the bonding functional group and the main chain, the particularly preferred linking group is a -CO-O- group or a -CO-N(R N )-base(R N As described above. ) and an alkylene or polyalkyleneoxy chain.

[0196] There are no particular limitations on the method for incorporating functional groups into polymer chains. Examples include methods using a compound copolymerizable with a compound having a functional group selected from functional group group (a), methods using a polymerization initiator or chain transfer agent having (generating) such a functional group, and methods utilizing polymer reactions. Furthermore, functional groups can be introduced by using functional groups present in the main chain, side chain, or terminal of a polymer as reaction sites. For example, as shown in the Examples below, functional groups selected from functional group group (a) can be introduced by using a compound having a functional group and reacting with a carboxylic anhydride group in the polymer chain in various ways.

[0197] There is no particular limitation on the compound having the above-mentioned functional group, and for example, compounds having at least one carbon-carbon unsaturated bond and the above-mentioned functional group can be cited. For example, compounds formed by direct bonding of a carbon-carbon unsaturated bond to the above-mentioned functional group, compounds formed by bonding of a carbon-carbon unsaturated bond to the above-mentioned functional group via a linker, and compounds in which the functional group itself comprises a carbon-carbon unsaturated bond (for example, the above-mentioned polymerizable cyclic carboxylic anhydride). Furthermore, compounds having the above-mentioned functional group include compounds capable of introducing functional groups into polymer constituents after polymerization by various reactions (for example, compounds capable of undergoing addition reaction or condensation reaction with constituents derived from carboxylic anhydride, constituents having carbon-carbon unsaturated bonds, etc., alcohols, amino groups, thiol groups or epoxy groups (including polymers)). In addition, compounds having the above-mentioned functional groups also include compounds in which a carbon-carbon unsaturated bond is bonded directly or via a linker to a macromonomer having a functional group incorporated as a substituent in the polymer chain (for example, AS-6 (trade name, styrene macromonomer, manufactured by Toagosei Company, Limited) described in the Examples below). Examples of macromonomers that can be incorporated into the macromonomer constituent include macromonomers having a polymer chain of the chain-polymerized polymer described below.

[0198] The number average molecular weight of the macromonomer is not particularly limited. From the perspective of maintaining excellent dispersion characteristics and coating suitability while making the binding force of solid particles and the adhesion to the collector more solid, it is preferably 500-100,000, more preferably 1,000-50,000, and further preferably 2,000-20,000. In addition, the content of the repeating unit with the functional group incorporated into the macromonomer is preferably 1-100 mol%, more preferably 3-80 mol%, and further preferably 5-70 mol%. The content of the repeating unit without functional groups is preferably 0-90 mol%, more preferably 0-70 mol%, and further preferably 0-50 mol%. From the perspective of solubility, any component can be selected.

[0199] The constituent having the above-mentioned functional group is not particularly limited as long as it has the above-mentioned functional group. Examples thereof include the (meth)acrylic acid compound (M1) or other polymerizable compound (M2) described later, the constituent represented by any one of the formulas (b-1) to (b-3) described later, and the constituent obtained by introducing the above-mentioned functional group into the constituent represented by the formula (1-1) described later.

[0200] The compound into which the constituent having the above-mentioned functional group is introduced is not particularly limited, and examples thereof include compounds into which the above-mentioned functional group is introduced into polymerizable cyclic carboxylic acid anhydrides and short-chain alkyl (meth)acrylate compounds containing a fluoroalkyl group (a short-chain alkyl group refers to an alkyl group having 3 or less carbon atoms).

[0201] The content of the constituent having the functional group in the polymer is not particularly limited as long as the adsorption rate of the polymer binder to the inorganic solid electrolyte can be suppressed to 50% or less.

[0202] From the viewpoint of solid particle binding properties, it is preferably 0.01 to 80 mol%, more preferably 0.01 to 70 mol%, further preferably 0.1 to 50 mol%, and particularly preferably 0.3 to 50 mol%. The lower limit of the content can also be 5 mol% or more or 20 mol% or more.

[0203] When a polymer has a plurality of constituents having functional groups, the content of the constituents having functional groups is set to the total amount. Furthermore, when a constituent has multiple or multiple functional groups, the content of the constituent having functional groups generally refers to the content of the constituent. Wherein, for the SEBS adhesive described later, due to the relationship with the adsorption rate of the SEBS adhesive, etc., for convenience, it is set to the total amount of the content of each functional group. Wherein, when multiple or multiple functional groups are present in one molecular chain (when derived from a common raw material compound), the content of each functional group is not included in the above total amount, and the multiple or multiple functional groups are summarized as one functional group and included in the total amount.

[0204] When two or more polymer binders are contained, the content of the constituent having the functional group relative to the total number of moles of the polymer constituents forming all the polymer binders is not particularly limited and can be appropriately set depending on the content in each polymer.

[0205] -Substituent Z-

[0206] Examples thereof include alkyl groups (preferably alkyl groups having 1 to 20 carbon atoms, for example, methyl, ethyl, isopropyl, tert-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.), alkenyl groups (preferably alkenyl groups having 2 to 20 carbon atoms, for example, vinyl, allyl, oleyl, etc.), alkynyl groups (preferably alkynyl groups having 2 to 20 carbon atoms, for example, ethynyl, butadiynyl, phenylethynyl, etc.), and cycloalkyl groups (preferably cycloalkyl groups having 3 to 20 carbon atoms, for example, cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc.). In the present specification, when an alkyl group is used, , usually means including cycloalkyl, but is described separately here. ), aryl (preferably an aryl having 6 to 26 carbon atoms, for example, phenyl, 1-naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methylphenyl, etc.), aralkyl (preferably an aralkyl having 7 to 23 carbon atoms, for example, benzyl, phenethyl, etc.), heterocyclic group (preferably a heterocyclic group having 2 to 20 carbon atoms, more preferably a 5- or 6-membered heterocyclic group having at least one oxygen atom, sulfur atom, or nitrogen atom. Heterocyclic groups include aromatic heterocyclic groups and aliphatic heterocyclic groups. For example, tetrahydropyranyl, tetrahydrofuranyl, 2-pyranyl 1-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-oxazolyl, pyrrolidonyl, etc.), alkoxy (preferably an alkoxy group having 1 to 20 carbon atoms, for example, methoxy, ethoxy, isopropyloxy, benzyloxy, etc.), aryloxy (preferably an aryloxy group having 6 to 26 carbon atoms, for example, phenoxy, 1-naphthyloxy, 3-methylphenoxy, 4-methoxyphenoxy, etc., and the term "aryloxy" in this specification includes aroyloxy), heterocyclic oxy (a group in which an -O- group is bonded to the above heterocyclic group), alkoxycarbonyl (preferably an alkoxy group having 2 to 20 carbon atoms), Alkoxycarbonyl, for example, ethoxycarbonyl, 2-ethylhexyloxycarbonyl, dodecyloxycarbonyl, etc.), aryloxycarbonyl (preferably aryloxycarbonyl having 6 to 26 carbon atoms, for example, phenoxycarbonyl, 1-naphthyloxycarbonyl, 3-methylphenoxycarbonyl, 4-methoxyphenoxycarbonyl, etc.), amino (preferably amino, alkylamino, arylamino having 0 to 20 carbon atoms, for example, amino (-NH2), N,N-dimethylamino, N,N-diethylamino, N-ethylamino, anilino, etc.), sulfamoyl (preferably sulfamoyl having 0 to 20 carbon atoms, for example, N,N-dimethylsulfamoyl, N-phenylsulfamoyl, etc.), acyl group (including alkylcarbonyl, alkenylcarbonyl, alkynylcarbonyl, arylcarbonyl, heterocyclic carbonyl, preferably acyl group having 1 to 20 carbon atoms, for example, acetyl, propionyl, butyryl, octanoyl, hexadecanoyl, acryloyl, methacryloyl, crotonyl, benzoyl, naphthoyl, nicotinoyl, etc.), acyloxy group (including alkylcarbonyloxy, alkenylcarbonyloxy, alkynylcarbonyloxy, arylcarbonyloxy, heterocyclic carbonyloxy, preferably acyloxy group having 1 to 20 carbon atoms, for example, acetyloxy, propionyloxy, butyryloxy, octanoyloxy , hexadecanoyloxy, acryloyloxy, methacryloyloxy, crotonoyloxy, benzoyloxy, naphthoyloxy, nicotinoyloxy, etc.), aryloxy (preferably aryloxy having 7 to 23 carbon atoms, for example, benzoyloxy, etc.), carbamoyl (preferably carbamoyl having 1 to 20 carbon atoms, for example, N,N-dimethylcarbamoyl, N-phenylcarbamoyl, etc.), acylamino (preferably acylamino having 1 to 20 carbon atoms, for example, acetylamino, benzylamino, etc.), alkylthio (preferably alkylthio having 1 to 20 carbon atoms, for example, methylthio, ethylthio, isopropylthio , benzylthio, etc.), arylthio (preferably an arylthio group having 6 to 26 carbon atoms, for example, phenylthio, 1-naphthylthio, 3-methylphenylthio, 4-methoxyphenylthio, etc.), a heterocyclic thio group (a group in which an -S- group is bonded to the above-mentioned heterocyclic group), an alkylsulfonyl group (preferably an alkylsulfonyl group having 1 to 20 carbon atoms, for example, methylsulfonyl, ethylsulfonyl, etc.), an arylsulfonyl group (preferably an arylsulfonyl group having 6 to 22 carbon atoms, for example, benzylsulfonyl, etc.), an alkylsilyl group (preferably an alkylsilyl group having 1 to 20 carbon atoms, for example, monomethylsilyl, dimethylsilyl , trimethylsilyl, triethylsilyl, etc.), arylsilyl (preferably an arylsilyl group having 6 to 42 carbon atoms, for example, triphenylsilyl, etc.), alkoxysilyl (preferably an alkoxysilyl group having 1 to 20 carbon atoms, for example, monomethoxysilyl, dimethoxysilyl, trimethoxysilyl, triethoxysilyl, etc.), aryloxysilyl (preferably an aryloxysilyl group having 6 to 42 carbon atoms, for example, triphenoxysilyl, etc.), phosphoyl (preferably a phosphate group having 0 to 20 carbon atoms, for example, -OP(=O)(R, P ) 2), phosphono group (preferably a phosphono group having 0 to 20 carbon atoms, for example, -P(=O)(R P ) 2), phosphinyl group (preferably a phosphinyl group having 0 to 20 carbon atoms, for example, -P(R P ) 2), phosphonic acid group (preferably a phosphonic acid group having 0 to 20 carbon atoms, for example, -PO(OR P ) 2), sulfo group (sulfonic acid group), carboxyl group, hydroxyl group, sulfanyl group, cyano group, halogen atom (such as fluorine atom, chlorine atom, bromine atom, iodine atom, etc.). R Pis a hydrogen atom or a substituent (preferably a group selected from the substituent Z).

[0207] Furthermore, each group listed in these substituents Z may be further substituted by the substituents Z described above.

[0208] The above-mentioned alkyl group, alkylene group, alkenyl group, alkenylene group, alkynyl group and / or alkynylene group etc. may be cyclic or chain-like, and may be linear or branched.

[0209] 〔Fluoropolymer〕

[0210] Examples of fluoropolymers include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), copolymers of polyvinylidene fluoride and hexafluoropropylene (PVdF-HFP), and copolymers of polyvinylidene fluoride, hexafluoropropylene, and tetrafluoroethylene (PVdF-HFP-TFE). In PVdF-HFP, the copolymerization ratio of PVdF to HFP [PVdF:HFP] (mass ratio) is not particularly limited, but is preferably 9:1 to 5:5, and more preferably 9:1 to 7:3 from the viewpoint of adhesion. In PVdF-HFP-TFE, the copolymerization ratio of PVdF to HFP and TFE [PVdF:HFP:TFE] (mass ratio) is not particularly limited, but is preferably 20 to 60:10 to 40:5 to 30, and more preferably 25 to 50:10 to 35:10 to 25.

[0211] 〔Hydrocarbon polymer〕

[0212] Examples of hydrocarbon polymers include polyethylene, polypropylene, natural rubber, polybutadiene, polyisoprene, polyfluorine, polyfluorobutadiene copolymers, fluorine-based thermoplastic elastomers, polybutene, acrylonitrile-butadiene copolymers, and hydrogenated (hydrogenated) polymers thereof. Examples of styrene-based thermoplastic elastomers and their hydrogenates include, but are not limited to, styrene-ethylene-butylene-styrene block copolymers (SEBS), styrene-isoprene-styrene block copolymers (SIS), hydrogenated SIS, styrene-butadiene-styrene block copolymers (SBS), hydrogenated SBS, styrene-ethylene-ethylene-propylene-styrene block copolymers (SEEPS), styrene-ethylene-propylene-styrene block copolymers (SEPS), styrene-butadiene rubber (SBR), hydrogenated styrene-butadiene rubber (HSBR), and random copolymers corresponding to the above block copolymers, such as SEBS. In the present invention, the hydrocarbon polymer is preferred in that the polymer having no unsaturated group (eg, 1,2-butadiene constituent) bonded to the main chain can suppress the formation of chemical crosslinks.

[0213] The hydrocarbon polymer preferably contains, in addition to the constituent components (e.g., styrene) constituting the hydrocarbon polymer described above, constituent components derived from compounds having functional groups selected from the functional group group (a) (constituent components having functional groups). For example, constituent components derived from polymerizable cyclic carboxylic acid anhydrides such as maleic anhydride can be cited. In addition, constituent components having functional groups also include constituent components formed by introducing functional groups selected from the functional group group (a) into copolymerized constituent components through various reactions (e.g., copolymerized components of SEBS binder (B-1) synthesized in the examples). Thus, the adsorption rate of the polymer binder to the inorganic solid electrolyte can be adjusted to satisfy the relationship represented by the above formula (1).

[0214] The content of components derived from compounds having a functional group selected from the functional group group (a) above, excluding the components constituting the hydrocarbon polymer described above (e.g., styrene), in all components constituting the hydrocarbon polymer is preferably 0.01 mol% or more, more preferably 0.02 mol% or more, even more preferably 0.05 mol% or more, and particularly preferably 0.1 mol% or more. The upper limit is preferably 10 mol% or less, more preferably 8 mol% or less, and even more preferably 5 mol% or less, based on all components constituting the hydrocarbon polymer.

[0215] When a hydrocarbon polymer contains multiple components with functional groups, the content of these components is the total amount. Furthermore, when a single component contains multiple or more functional groups, the content of these components is typically the content of that component alone. However, in the present invention, based on the relationship with the adsorption rate of the SEBS binder, for convenience, the total amount of each functional group is used. If multiple or more functional groups are present in a single molecular chain (derived from a common raw material compound), the total amount does not include the content of each functional group; instead, the multiple or more functional groups are aggregated and included as a single functional group in the total amount.

[0216] 〔Ethylene polymer〕

[0217] As the ethylene polymer, for example, a polymer containing ethylene monomers other than the (meth) acrylic acid compound (M1) containing more than 50 mol %. As the ethylene monomer, vinyl compounds described below can be enumerated. As the ethylene polymer, specifically, for example, polyvinyl alcohol, polyvinyl acetal, polyvinyl acetate or a copolymer comprising these can be enumerated.

[0218] The ethylene polymer preferably has, in addition to the constituents derived from the ethylene monomer, a constituent derived from the (meth)acrylic acid compound (M1) that forms the (meth)acrylic acid polymer described later. The content of the constituent derived from the ethylene monomer is preferably the same as the content of the constituent derived from the (meth)acrylic acid compound (M1) in the (meth)acrylic acid polymer. The content of the constituent derived from the (meth)acrylic acid compound (M1) is not particularly limited as long as it is less than 50 mol% in the polymer, but is preferably 0 to 30 mol%. The content of the constituent (MM) is preferably the same as that in the (meth)acrylic acid polymer.

[0219] [(Meth)acrylic acid polymer]

[0220] As a (meth) acrylic polymer, it is preferred that a polymer is obtained by copolymerizing at least one (meth) acrylic compound (M1) selected from a (meth) acrylic acid compound, a (meth) acrylic ester compound, a (meth) acrylamide compound and a (meth) acrylic nitrile compound. In addition, a (meth) acrylic polymer composed of a copolymer of a (meth) acrylic acid compound (M1) and other polymerizable compounds (M2) is also preferred. There is no particular limitation on other polymerizable compounds (M2), and vinyl compounds such as styrene compounds, vinyl naphthalene compounds, vinyl carbazole compounds, allyl compounds, vinyl ether compounds, vinyl ester compounds, itaconic acid dialkyl compounds, unsaturated carboxylic acid anhydrides and these fluorides can be mentioned. As a vinyl compound, for example, the "vinyl monomers" described in Japanese Patent Application Laid-Open No. 2015-88486 can be mentioned.

[0221] The (meth)acrylic acid compound (M1) and the other polymerizable compound (M2) may have a substituent. The substituent is not particularly limited, but a group selected from the substituent Z described above is preferred.

[0222] The content of the other polymerizable compound (M2) in the (meth)acrylic polymer is not particularly limited, and can be, for example, 50 mol% or less.

[0223] (i) Compound represented by formula (b-1)

[0224] In the (meth)acrylic acid compound (M1) and the other polymerizable compound (M2) introduced as the constituent components of the (meth)acrylic acid polymer, the constituent components having the functional groups contained in the functional group (a) and the compounds represented by the later-described formula (1-1) are introduced as different compounds, and preferably, a compound represented by the following formula (b-1) is used.

[0225] [Chemical Formula 2]

[0226]

[0227] Where R 1 represents a hydrogen atom, a hydroxyl group, a cyano group, a halogen atom, an alkyl group (preferably having 1 to 24 carbon atoms, more preferably 1 to 12, and particularly preferably 1 to 6), an alkenyl group (preferably having 2 to 24 carbon atoms, more preferably 2 to 12, and particularly preferably 2 to 6), 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, more preferably 6 to 14 carbon atoms). Among them, a hydrogen atom or an alkyl group is preferred, and a hydrogen atom or a methyl group is more preferred.

[0228] R 2 Represents a hydrogen atom or a substituent. 2 The substituents are not particularly limited and include alkyl groups (which may be branched, but are preferably straight-chain), alkenyl groups (preferably having 2 to 12 carbon atoms, more preferably 2 to 6, and particularly preferably 2 or 3), aryl groups (preferably having 6 to 22 carbon atoms, more preferably 6 to 14 carbon atoms), aralkyl groups (preferably having 7 to 23 carbon atoms, more preferably 7 to 15 carbon atoms), and cyano groups.

[0229] The alkyl group preferably has a carbon number of 1 to 3. The alkyl group may have, for example, a group other than the functional groups included in the functional group group (a) in the substituent Z described above.

[0230] L 1 is a linking group, which is not particularly limited, and examples thereof include an alkylene group having 1 to 6 carbon atoms (preferably 1 to 3), an alkenylene group having 2 to 6 carbon atoms (preferably 2 to 3), an arylene group having 6 to 24 carbon atoms (preferably 6 to 10), an oxygen atom, a sulfur atom, an imino group (-NR N -:R N As mentioned above. ), carbonyl, phosphate linking group (-OP(OH)(O)-O-), phosphonic acid linking group (-P(OH)(O)-O-) or a combination thereof, preferably -CO-O-, -CO-N(R N )-base(R N As described above.). The above-mentioned linking group may have an arbitrary substituent. The number of atoms constituting the linking group and the number of connecting atoms are described below. As an arbitrary substituent, the above-mentioned substituent Z can be mentioned, for example, an alkyl group or a halogen atom can be mentioned.

[0231] n is 0 or 1, preferably 1. When n is 0, it means R 2 Relative to R 1 The bonded carbon atoms are directly bonded. 1 ) n -R 2 When a substituent (such as an alkyl group) is represented, n is set to 0 and R 2 Let it be a substituent (alkyl).

[0232] (ii) Compound represented by formula (b-2) or (b-3)

[0233] In the (meth)acrylic compound (M1), the compound introduced with the constituent having the functional group contained in the functional group group (a) and the constituent represented by the formula (1-1) described below are different compounds, and preferably, a compound represented by the following formula (b-2) or (b-3) is also mentioned.

[0234] [Chemical Formula 3]

[0235]

[0236] R 1 and n have the same meanings as in the above formula (b-1).

[0237] R 3 R of the above formula (b-1) 2 Same meaning.

[0238] L 2 As a linking group, the above-mentioned L can be preferably used 1 Records of.

[0239] L 3 As a linking group, the above-mentioned L can be preferably used 1 The description of alkylene is preferably an alkylene group having 1 to 6 carbon atoms (preferably 1 to 3).

[0240] m is an integer of 1-200, preferably an integer of 1-100, and more preferably an integer of 1-50.

[0241] In the above formulas (b-1) to (b-3), the carbon atom forming the polymerizable group and not bonded to R 1 The carbon atom is represented by an unsubstituted carbon atom (H2C=), but may have a substituent. There are no particular restrictions on the substituent, but for example, R 1 of the above groups.

[0242] Furthermore, in formulas (b-1) to (b-3), groups having substituents, such as alkyl groups, aryl groups, alkylene groups, and arylene groups, may have substituents within the range that does not impair the effects of the present invention. The substituents may be any substituents other than the functional groups selected from functional group group (a), and examples thereof include groups selected from the substituent Z described above, and specifically, halogen atoms and the like.

[0243] (iii) Constituents represented by formula (1-1)

[0244] The (meth)acrylic polymer preferably has a constituent represented by the following formula (1-1), and more preferably contains a constituent having a (meth)acrylate structure represented by the following formula (1-1). When two or more polymer binders are contained, the polymer forming at least one polymer binder is preferably a (meth)acrylic polymer having a constituent represented by the following formula (1-1). It is also preferred that all (meth)acrylic polymers contain this constituent.

[0245] If the (meth)acrylic polymer forming the polymer binder has a constituent represented by the following formula (1-1), the adsorption rate of the polymer binder to the inorganic solid electrolyte can be reduced, and the dispersion characteristics and coating suitability of the inorganic solid electrolyte-containing composition can be improved. In addition to the (meth)acrylic polymer, chain polymers such as fluorine-based polymers, hydrocarbon-based polymers, or vinyl-based polymers can also achieve the same effects as the (meth)acrylic polymer by having a constituent represented by the following formula (1-1), and can improve the dispersion characteristics and coating suitability of the inorganic solid electrolyte-containing composition.

[0246] [Chemical Formula 4]

[0247]

[0248] In formula (1-1), R 1 represents a hydrogen atom or an alkyl group (the number of carbon atoms is preferably 1 to 12, more preferably 1 to 6, and even more preferably 1 to 3). 1 The alkyl group may have a substituent. The substituent is not particularly limited, and examples thereof include the above-mentioned substituent Z, etc., and is preferably a group other than the functional group selected from the functional group group (a), for example, a halogen atom, etc.

[0249] R 2 In the present invention, the group having a hydrocarbon group includes a group consisting of a hydrocarbon group itself (a hydrocarbon group directly bonded to R 1 The carbon atom in the above formula to which the bond is attached. 2 The carbon atom and the hydrocarbon group in the above formula are bonded to the linking group and the group consisting of the hydrocarbon group (the hydrocarbon group is bonded to R via the linking group) 1 The carbon atom in the above formula to which it is bonded. ).

[0250] A hydrocarbon group is a group composed of carbon atoms and hydrogen atoms, usually introduced into R 2The hydrocarbon group is not particularly limited, but is preferably an aliphatic hydrocarbon group, more preferably an aliphatic saturated hydrocarbon group (alkyl group), and even more preferably a linear or branched alkyl group. The hydrocarbon group may have 4 or more carbon atoms, preferably 6 or more, and more preferably 10 or more. The upper limit is not particularly limited, but is preferably 20 or less, and more preferably 14 or less.

[0251] The linking group is not particularly limited, and examples thereof include an alkylene group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6, and even more preferably 1 to 3 carbon atoms), an alkenylene group (preferably having 2 to 6 carbon atoms, more preferably 2 to 3 carbon atoms), an arylene group (preferably having 6 to 24 carbon atoms, more preferably 6 to 10 carbon atoms), an oxygen atom, a sulfur atom, an imino group (-NR N -:R N represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms. ), a carbonyl group, a phosphate linking group (-OP(OH)(O)-O-), a phosphonic acid linking group (-P(OH)(O)-O-), or a group related to a combination thereof. An alkylene group and an oxygen atom can also be combined to form a polyalkyleneoxy chain. As a linking group, a group composed of an alkylene group, an arylene group, a carbonyl group, an oxygen atom, a sulfur atom, and an imino group is preferred, a group composed of an alkylene group, an arylene group, a carbonyl group, an oxygen atom, and an imino group is more preferred, and a group containing a -CO-O- group, a -CO-N(R N )-base(R N As mentioned above. ) group, particularly preferably -CO-O- group or -CO-N(R N )-base(R N As described above. ), the most preferred is a -CO-O- group. The number of atoms constituting the linking group and the number of connecting atoms are described below. However, the polyalkyleneoxy chain constituting the linking group is not limited to the above.

[0252] In the present invention, the number of atoms constituting the linking group is preferably 1 to 36, more preferably 1 to 24, further preferably 1 to 12, and particularly preferably 1 to 6. The number of connecting atoms of the linking group is preferably 10 or less, more preferably 8 or less. The lower limit is 1 or more. The above-mentioned number of connecting atoms refers to the minimum number of atoms connecting the specified structural parts. For example, in the case of -CH2-C(=O)-O-, the number of atoms constituting the linking group becomes 6, but the number of connecting atoms becomes 3.

[0253] The hydrocarbon group and the linking group may or may not have a substituent. Examples of the substituent include the substituent Z, which is preferably a group other than the functional group selected from the functional group group (a), and preferably a halogen atom.

[0254] In the above formula (1-1), R 1The carbon atom adjacent to the bonded carbon atom has two hydrogen atoms, but in the present invention, it may have one or two substituents. The substituent is not particularly limited, and examples thereof include the aforementioned substituent Z, etc., and is preferably a group other than the functional group selected from the functional group group (a).

[0255] The compound into which the constituent component represented by formula (1-1) is introduced is not particularly limited, and examples thereof include linear alkyl (meth)acrylate compounds (linear alkyl refers to an alkyl group having 4 or more carbon atoms).

[0256] The content of the constituent represented by the above formula (1-1) in the polymer is not particularly limited. From the viewpoint of improving dispersion characteristics and coating suitability, it is preferably 10 to 100 mol%, more preferably 20 to 99.9 mol%, further preferably 30 to 99.5 mol%, and particularly preferably 30 to 99 mol%, among which 30 to 98 mol% is preferred, and 50 to 96 mol% is further preferred.

[0257] When two or more polymer binders are contained, the content of the component represented by formula (1-1) relative to the total number of moles of the polymer components forming all the polymer binders is not particularly limited and can be appropriately set according to the content in each polymer.

[0258] The (meth)acrylic polymer preferably contains a constituent having a functional group selected from the functional group group (a) and a constituent represented by the above formula (1-1). Furthermore, in addition to these constituents, it may also contain constituents derived from the (meth)acrylic compound (M1), constituents derived from the vinyl compound (M2), and other constituents capable of copolymerizing with compounds into which these constituents are introduced. From the perspectives of dispersion characteristics and coating suitability, it is preferred to contain a constituent represented by the above formula (1-1) and a constituent having a functional group selected from the functional group group (a) in the (meth)acrylic compound (M1).

[0259] The content of the constituent components in the (meth)acrylic polymer is not particularly limited and can be appropriately selected in consideration of the structural unit or the SP value of the polymer, and can be set, for example, within the following ranges. The content of the constituent components represented by the formula (1-1) is as described above.

[0260] The content of the constituents derived from the (meth)acrylic acid compound (M1) in the (meth)acrylic acid polymer is not particularly limited and may be 100 mol%. When the constituents derived from the vinyl compound (M2) are used as copolymerization components, the remainder of the constituents derived from the vinyl compound (M2) described below is preferably a (meth)acrylic acid compound.

[0261] The content of the constituent component derived from the vinyl compound (M2) in the (meth)acrylic polymer is not particularly limited, but is preferably 1 to 50 mol%, more preferably 1 to 30 mol%, further preferably 1 to 20 mol%, and particularly preferably 2.5 to 20 mol%.

[0262] The content of the constituent having a functional group selected from the functional group group (a) in the (meth)acrylic polymer is not particularly limited, but is preferably 0.01 to 50 mol%, more preferably 0.01 to 30 mol%, further preferably 0.1 to 10 mol%, and particularly preferably 0.5 to 10 mol%.

[0263] The chain polymer preferably contains a constituent having a functional group selected from the functional group group (a) or a constituent represented by the formula (1-1), more preferably contains a constituent having a functional group selected from the functional group group (a), and even more preferably contains a constituent having a functional group selected from the functional group group (a) and a constituent represented by the formula (1-1). Furthermore, the chain polymer may contain constituents different from these constituents.

[0264] The chain polymer (each component and raw material compound) may have a substituent. The substituent is not particularly limited as long as it is a group other than the functional groups included in the functional group group (a), and preferably a group selected from the substituent Z mentioned above.

[0265] The chain polymerization polymer can be synthesized by selecting a raw material compound by a known method and polymerizing the raw material compound.

[0266] The method for incorporating the functional group is not particularly limited, and examples thereof include copolymerization with a compound having a functional group selected from functional group group (a), a method using a polymerization initiator or chain transfer agent having (generating) the above-mentioned functional group, a method utilizing a polymer reaction, an ene reaction in a double bond (for example, in the case of a fluoropolymer, formed by a dehydrofluorination reaction of a VDF constituent), an ene-thiol reaction, or ATRP (Atom Transfer Radical Polymerization) polymerization method using a copper catalyst.

[0267] (Physical properties or characteristics of polymers, etc.)

[0268] The polymer preferably has the following physical properties or characteristics.

[0269] The water concentration of the polymer is preferably 100 ppm (mass basis) or less. The polymer may be crystallized and then dried, or the polymer solution may be used as it is.

[0270] The polymer is preferably amorphous. In the present invention, the polymer being "amorphous" typically means that no endothermic peak due to crystal melting is observed when measured at the glass transition temperature.

[0271] The polymer forming the polymer binder preferably has an SP value of, for example, 10 to 24 MPa from the viewpoint of dispersion stability of solid particles. 1 / 2 , the SP value is more preferably 14 to 22 MPa 1 / 2 , SP value is more preferably 16 to 20 MPa 1 / 2 The difference (absolute value) in SP value between the polymer forming the polymer binder and the dispersion medium will be described later.

[0272] The calculation method of the SP value is described.

[0273] (1) Calculate the SP value of the structural unit.

[0274] First, for a polymer, a structural unit that specifies an SP value is determined.

[0275] That is, in the present invention, when calculating the SP value of a polymer, when the polymer (segment) is a chain polymerization polymer, it is set as a structural unit that is the same as the constituent component derived from the raw material compound. When the polymer is a step-polymerization (polycondensation, polyaddition or addition condensation) polymer such as polyurethane, polyurea, polyamide, polyimide, polyester, it is set as a unit that is different from the constituent component derived from the raw material compound. For example, as a step-polymerization polymer, taking polyurethane as an example, the structural unit for specifying the SP value is specified as follows. As a structural unit derived from a polyisocyanate compound, it is a unit (a unit having one carbamate bond) formed by bonding an -O- group to one -NH-CO- group and removing the remaining -NH-CO- group relative to the constituent component derived from the polyisocyanate compound. On the other hand, as a structural unit derived from a polyol compound, it is a unit (a unit having one carbamate bond) formed by bonding a -CO-NH- group to one -O- group and removing the remaining -O- group relative to the constituent component derived from the polyol compound. In addition, in the case of other step-polymerization polymers, the structural unit is determined in the same manner as for polyurethane.

[0276] Next, unless otherwise specified, the SP value of each structural unit was determined by the Hoy method (refer to HL Hoy JOURNAL OF PAINT TECHNOLOGY Vol. 42, No. 541, 1970, 76-118 and POLYMER HANDBOOK 4 th , Chapter 59, Page VII 686, Table 5, Table 6 and the formulas in Table 6).

[0277] [Formula 1]

[0278]

[0279] Where, δ t Indicates SP value. F t represents the Molar attraction function

[0280] (J×cm 3 ) 1 / 2 / mol, is represented by the following formula. V represents the molar volume (cm 3 / mol), represented by the following formula.

[0281] It is represented by the following formula.

[0282] F t =∑n i F t，i V=∑n i V i

[0283]

[0284] In the above formula, F t，i represents the molar attraction function of each structural unit, V i Represents the molar mass of each structural unit

[0285] Product, Δ (P) T，i Represents the correction value of each structural unit, n i Indicates the number of each structural unit.

[0286] (2) SP value of polymer

[0287] The SP value determined as described above was used to calculate the SP value using the following formula. In addition, the SP value of the structural unit obtained from the above literature was converted into the SP value (unit: MPa) 1 / 2 )(For example, 1 cal 1 / 2 cm -3 / 2 ≈2.05J 1 / 2 cm -3 / 2 ≈2.05MPa 1 / 2 ) and use it.

[0288] SP p 2 =(SP1 2 ×W1)+(SP2 2 ×W2)+……

[0289] Wherein, SP1, SP2, ... represent the SP value of the structural unit, and W1, W2, ... represent the mass fraction of the structural unit.

[0290] In the present invention, the mass fraction of a structural unit refers to the mass fraction of a constituent component corresponding to the structural unit (a raw material compound into which the constituent component is introduced) in a polymer.

[0291] The SP value of a polymer can be adjusted by the type and composition (type and content of constituent components) of the polymer.

[0292] In the present invention, the SP value of the polymer is calculated by the above formula for all structural units. In the case where the polymer contains a constituent component derived from a macromonomer, it can also be set to the SP value (excluding MM) calculated by the above formula without the structural unit corresponding to the constituent component derived from the macromonomer (MM). According to the SP value (excluding MM) calculated in this way, the dispersion characteristics can be further improved. As the SP value (excluding MM), it can also be set to the same range as the above-mentioned SP value, preferably 13.0 to 22.5 MPa 1 / 2 , more preferably 16.0 to 21.0 MPa 1 / 2 , more preferably 17.5 to 20.5 MPa 1 / 2 .

[0293] The polymer may be a non-crosslinked polymer or a crosslinked polymer. Furthermore, when the polymer is crosslinked by heating or applying a voltage, the molecular weight may be greater than the above molecular weight. Preferably, when the all-solid-state secondary battery is first used, the mass average molecular weight of the polymer is within the range described below.

[0294] The mass average molecular weight of the polymer is not particularly limited, but is preferably 8,000 or more, for example.

[0295] When the dispersion medium contains a compound having a polar functional group, for example, at least one selected from ester compounds, ketone compounds, ether compounds, alcohol compounds, amide compounds, amine compounds, and nitrile compounds, the mass average molecular weight of the polymer is more preferably 10,000 or more, further preferably 30,000 or more, and particularly preferably 60,000 or more, from the viewpoint of dispersion characteristics and coating suitability. The upper limit is practically 1,000,000 or less, preferably 700,000 or less, more preferably 500,000 or less, further preferably 300,000 or less, and particularly preferably 100,000 or less.

[0296] On the other hand, when the dispersion medium contains at least one selected from aromatic compounds and aliphatic compounds, the mass average molecular weight of the polymer is more preferably 70,000 or more, further preferably 150,000 or more, and particularly preferably 300,000 or more, from the viewpoint of dispersion characteristics and coating suitability. The upper limit is practically 2,000,000 or less, preferably 1,000,000 or less, more preferably 800,000 or less, and particularly preferably 600,000 or less.

[0297] In the present invention, "the dispersion medium contains a compound having a polar functional group" means that as long as the effect of the present invention is exerted, the dispersion medium may contain a dispersion medium other than a compound having a polar functional group. For example, the content of the dispersion medium other than a compound having a polar functional group in all dispersion media can be set to 50% or less, preferably 20% by mass or less, more preferably 10% by mass or less, and further preferably 3% by mass or less. It may not contain any dispersion medium at all.

[0298] The compound having a polar functional group as the dispersion medium preferably contains at least one selected from ester compounds, ketone compounds, and ether compounds.

[0299] Furthermore, in the present invention, "comprising at least one selected from aromatic compounds and aliphatic compounds" means that a dispersion medium other than aromatic compounds and aliphatic compounds may be contained as long as the effect of the present invention is achieved. For example, the content of dispersion medium other than aromatic compounds and aliphatic compounds in all dispersion media can be set to less than 50%, preferably less than 20 mass%, more preferably less than 10 mass%, and further preferably less than 3 mass%. It may not be contained at all.

[0300] The reason why the preferred mass average molecular weight range of the polymer differs between when the dispersion medium contains at least one selected from aromatic compounds and aliphatic compounds and when the dispersion medium contains a compound having the polar functional group is not clear, but is presumed as follows.

[0301] That is, since the compound having the above-mentioned polar functional group has a polar functional group, the dispersion medium itself can prepare a thick slurry by improving the dispersibility of the inorganic solid electrolyte and, in turn, improving the dispersibility of the active material. On the other hand, since aromatic compounds and aliphatic compounds do not have polar functional groups, it is difficult to prepare a thick slurry when a dispersion medium containing at least one of these compounds is used. Therefore, it can be inferred that when a dispersion medium containing at least one selected from aromatic compounds and aliphatic compounds is used, by increasing the mass average molecular weight of the polymer compared to the case of using a dispersion medium containing the above-mentioned compound having a polar functional group, a thicker slurry can be prepared, and the dispersion characteristics and coating suitability can be improved.

[0302] When the inorganic solid electrolyte-containing composition contains a plurality of polymer binders, any one of the polymer binders may satisfy the above-mentioned mass average molecular weight in addition to satisfying the above-mentioned adsorption rate and the relationship defined by the above-mentioned formula (1).

[0303] -Determination of molecular weight-

[0304] In the present invention, the molecular weight of a polymer, polymer chain, or macromonomer, unless otherwise specified, refers to the mass average molecular weight or number average molecular weight calculated based on standard polystyrene obtained by gel permeation chromatography (GPC). The determination method is generally the value measured using the method of Condition 1 or Condition 2 (preferred) below. A suitable eluent may be selected and used depending on the type of polymer or macromonomer.

[0305] (Condition 1)

[0306] Column: A column consisting of two connected TOSOH TSKgel Super AWM-H (trade name, manufactured by TOSOH CORPORATION) was used.

[0307] Carrier: 10mMLiBr / N-methylpyrrolidone

[0308] Measurement temperature: 40°C

[0309] Carrier flow rate: 1.0ml / min

[0310] Sample concentration: 0.1 mass%

[0311] Detector: RI (refractive index) detector

[0312] (Condition 2)

[0313] Column: A column connected to TOSOH TSKgel Super HZM-H, TOSOH TSKgel Super HZ4000, or TOSOH TSKgel Super HZ2000 (all trade names, manufactured by Tosoh Corporation) was used.

[0314] Carrier: Tetrahydrofuran

[0315] Measurement temperature: 40°C

[0316] Carrier flow rate: 1.0ml / min

[0317] Sample concentration: 0.1 mass%

[0318] Detector: RI (refractive index) detector

[0319] Specific examples of polymers constituting the polymer binder include, in addition to those synthesized in the Examples, polymers having the structures shown below, but the present invention is not limited thereto. In each specific example, the number indicated to the lower right of the constituent component represents the content in the polymer, and the unit is mol %.

[0320] [Chemical Formula 5]

[0321]

[0322] The inorganic solid electrolyte-containing composition of the present invention may contain one polymer binder or may contain a plurality of polymer binders.

[0323] The (total) content of the polymer binder in the inorganic solid electrolyte-containing composition is not particularly limited, but is preferably 0.1 to 10.0% by mass, more preferably 0.2 to 5.0% by mass, and even more preferably 0.3 to 4.0% by mass from the viewpoint of improving dispersion characteristics and coating suitability, and furthermore exhibiting strong adhesion. For the same reason, the (total) content of the polymer binder in the inorganic solid electrolyte-containing composition is preferably 0.1 to 10.0% by mass, more preferably 0.3 to 8% by mass, and even more preferably 0.5 to 7% by mass, based on 100% by mass of the solid content.

[0324] When two or more polymer binders are contained, the content of each polymer binder is appropriately set within the range satisfying the above-mentioned (total) content.

[0325] When the inorganic solid electrolyte composition contains a particulate binder described later, the (total) content of the polymer binder may be lower than the content of the particulate binder, but is preferably the same or higher. Thus, the excellent dispersion characteristics and coating suitability are not damaged and the adhesion can be further enhanced. In 100% by mass of the solid component, the difference (absolute value) between the (total) content of the polymer binder and the content of the particulate binder is not particularly limited. For example, it can be set to 0 to 6% by mass, more preferably 0 to 4% by mass, and further preferably 0 to 2% by mass. In addition, in 100% by mass of the solid component, the ratio of the (total) content of the polymer binder to the content of the particulate binder (the (total) content of the polymer binder / the content of the particulate binder) is not particularly limited. For example, it is preferably 1 to 4, more preferably 1 to 2.

[0326] (Non-soluble adhesive)

[0327] The inorganic solid electrolyte composition of the present invention may contain one or more non-soluble binders that are insoluble in the dispersion medium in the composition in addition to the above-mentioned polymer binder. The non-soluble binder is preferably a particulate polymer binder (particulate binder). The shape of the particulate binder is not particularly limited and may be flat, amorphous, etc., preferably spherical or particulate. The average particle size of the particulate binder is preferably 1 to 1000 nm, more preferably 5 to 800 nm, further preferably 10 to 600 nm, and particularly preferably 50 to 500 nm. The average particle size can be measured in the same manner as the average particle size of the above-mentioned inorganic solid electrolyte.

[0328] The adsorption rate of the particulate binder on the inorganic solid electrolyte is not particularly limited as long as it achieves the effects of the present invention. For example, it can be 30% or higher, preferably 40% or higher. The upper limit is not particularly limited. For example, it can be 95% or lower, preferably 90% or lower. The adsorption rate on the active material can be determined as appropriate. The adsorption rate can be measured in the same manner as for the polymer binder described above.

[0329] The relationship between the surface energies of the particulate binder and the inorganic solid electrolyte is not particularly limited as long as the effects of the present invention are achieved. The sum of the squares of the differences in the dispersion components and the polarity components represented by the left side of the aforementioned formula (1) can be set to, for example, 30.0 2 Below, preferably set to 25.0 2 Below, more preferably set to 22.0 2 The lower limit is not particularly limited, and can be set to 0, for example, and is preferably 0.3 2 More than 0.6 2 More preferably, 0.9 2 The relationship between the surface energy of the particulate binder and the active material is not particularly limited. The dispersion component and polar component of the surface energy can be measured in the same manner as for the polymer binder described above.

[0330] If the inorganic solid electrolyte composition contains a particulate binder, the improved dispersion characteristics and coating suitability of the polymer binder are not impaired, and the binding properties of the solid particles can be enhanced while suppressing the increase in interfacial resistance. As a result, the cycle characteristics of the all-solid-state secondary battery can be further improved, and preferably, further resistance reduction can be achieved.

[0331] As the particulate adhesive, various particulate adhesives for manufacturing all-solid-state secondary batteries can be used without particular limitation. For example, a particulate adhesive composed of the above-mentioned chain polymerization polymer, a particulate adhesive composed of a stepwise polymerization polymer can be cited, and as described in the embodiments described later, commercially available products can be used. In addition, the adhesives described in Japanese Patent Application Publication No. 2015-088486, International Publication No. 2017 / 145894, International Publication No. 2018 / 020827, etc. can also be cited.

[0332] The content of the particulate binder in the inorganic solid electrolyte-containing composition is not particularly limited, but from the perspective of improving dispersion characteristics and coating suitability, and further exhibiting strong adhesion, it is preferably 0.01 to 4% by mass, more preferably 0.05 to 2% by mass, and even more preferably 0.1 to 1.5% by mass, based on 100% by mass of the solid content. The content of the particulate binder can be appropriately set within the above range, but considering the solubility of the particulate binder, it is preferably a content that does not dissolve in the inorganic solid electrolyte-containing composition.

[0333] Dispersion medium

[0334] The dispersion medium contained in the inorganic solid electrolyte-containing composition of the present invention is an organic compound that is liquid in the use environment. It can be any dispersion medium as long as it disperses the solid components contained in the composition. For example, various organic solvents can be mentioned, specifically, alcohol compounds, ether compounds, amide compounds, amine compounds, ketone compounds, aromatic compounds, aliphatic compounds, nitrile compounds, ester compounds, etc.

[0335] The dispersion medium may be a non-polar dispersion medium (hydrophobic dispersion medium) or a polar dispersion medium (hydrophilic dispersion medium). From the perspective of exhibiting excellent dispersibility, a non-polar dispersion medium is preferred. A non-polar dispersion medium generally refers to one having a low affinity for water. In the present invention, examples thereof include ester compounds, ketone compounds, ether compounds, aromatic compounds, and aliphatic compounds.

[0336] Examples of the alcohol compound include methanol, ethanol, 1-propanol, 2-propanol, 2-butanol, ethylene glycol, propylene glycol, glycerol, 1,6-hexanediol, cyclohexanediol, sorbitol, xylitol, 2-methyl-2,4-pentanediol, 1,3-butanediol, and 1,4-butanediol.

[0337] Examples of the ether compound include alkylene glycols (diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, etc.), alkylene glycol monoalkyl ethers (ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, diethylene glycol monobutyl ether, etc.), alkylene glycol dialkyl ethers (ethylene glycol dimethyl, etc.), dialkyl ethers (dimethyl ether, diethyl ether, diisopropyl ether, dibutyl ether, etc.), and cyclic ethers (tetrahydrofuran, dioxane (including 1,2-, 1,3-, and 1,4-isomers), etc.).

[0338] Examples of the amide compound include N,N-dimethylformamide, N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, formamide, N-methylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropaneamide, and hexamethylphosphoric triamide.

[0339] Examples of the amine compound include triethylamine, diisopropylethylamine, and tri-n-butylamine.

[0340] Examples of the ketone compound include acetone, methyl ethyl ketone, methyl isobutyl ketone (MIBK), cyclopentanone, cyclohexanone, cycloheptanone, dipropyl ketone, dibutyl ketone, diisopropyl ketone, diisobutyl ketone (DIBK), isobutyl propyl ketone, sec-butyl propyl ketone, amyl propyl ketone, and butyl propyl ketone.

[0341] Examples of the aromatic compound include benzene, toluene, and xylene.

[0342] Examples of the aliphatic compound include hexane, heptane, octane, decane, cyclohexane, methylcyclohexane, ethylcyclohexane, cyclooctane, decalin, paraffin, gasoline, naphtha, kerosine, kerosene, and light oil.

[0343] Examples of the nitrile compound include acetonitrile, propionitrile, and isobutyronitrile.

[0344] Examples of the ester compound include ethyl acetate, propyl acetate, butyl acetate, ethyl butyrate, propyl butyrate, isopropyl butyrate, butyl butyrate, isobutyl butyrate, butyl valerate, pentyl valerate, ethyl isobutyrate, propyl isobutyrate, isopropyl isobutyrate, isobutyl isobutyrate, propyl pivalate, isopropyl pivalate, butyl pivalate, and isobutyl pivalate.

[0345] In the present invention, among these, ether compounds, ketone compounds, aromatic compounds, aliphatic compounds, and ester compounds are preferred, and ester compounds, ketone compounds, and ether compounds are more preferred.

[0346] The number of carbon atoms in the compound constituting the dispersion medium is not particularly limited, but is preferably 2 to 30, more preferably 4 to 20, further preferably 6 to 15, and particularly preferably 7 to 12.

[0347] From the perspective of dispersion characteristics, the SP value (unit: MPa) of the dispersion medium 1 / 2 ) is preferably 15 to 21, more preferably 16 to 20, and further preferably 17 to 19. The difference (absolute value) between the SP value of the above-mentioned polymer binder and the dispersion medium is not particularly limited. From the viewpoint of further improving the dispersion characteristics, it is preferably 3.0 or less, more preferably 0 to 2.5, further preferably 0 to 2.0, and from the viewpoint of further improving the coating suitability, it is particularly preferably 0 to 1.7. When a plurality of polymer binders are contained, the difference (absolute value) of the SP value is preferably such that the minimum value (absolute value) is included in the above-mentioned range. More preferably, any polymer binder satisfies the above-mentioned range of the difference in SP value in addition to satisfying the above-mentioned adsorption rate and the relationship specified by the above-mentioned formula (1), and all differences (absolute values) can be included in the above-mentioned range.

[0348] The SP value of the dispersion medium is the SP value calculated by the above-mentioned Hoy method converted into a unit of MPa. 1 / 2 When the inorganic solid electrolyte-containing composition contains two or more dispersion media, the SP value of the dispersion medium refers to the SP value of the entire dispersion medium and is the sum of the products of the SP values ​​of each dispersion medium and the mass fraction. Specifically, the calculation is similar to the calculation method of the above-mentioned polymer SP value, except that the SP value of each dispersion medium is used instead of the SP value of the constituent component.

[0349] The SP values ​​of the dispersion medium are shown below (units omitted). In the following compound names, unless otherwise specified, alkyl refers to normal alkyl. For example, octane refers to normal octane.

[0350] MIBK (18.4), diisopropyl ether (16.8), dibutyl ether (17.9), diisobutyl ketone (17.9), DIBK (17.9), butyl butyrate (18.6), butyl acetate (18.9), toluene (18.5), xylene (a xylene isomer mixture with a molar ratio of ortho-isomer:para-isomer:meta-isomer = 1:5:2) (18.7), octane (16.9), ethylcyclohexane (17.1), cyclooctane (18.8), isobutyl ethyl ether (15.3), N-methylpyrrolidone (NMP, SP value: 25.4)

[0351] The boiling point of the dispersion medium at normal pressure (1 atm) is not particularly limited, but is preferably 90°C or higher, more preferably 120°C or higher. The upper limit is preferably 230°C or lower, more preferably 200°C or lower, and even more preferably 180°C or lower.

[0352] The inorganic solid electrolyte-containing composition of the present invention only needs to contain at least one dispersion medium, and may contain two or more.

[0353] In the present invention, the content of the dispersion medium in the inorganic solid electrolyte-containing composition is not particularly limited and is set within a range that satisfies the above-mentioned solid content concentration.

[0354] Active substances

[0355] The inorganic solid electrolyte composition of the present invention may further contain an active material capable of intercalating and deintercalating ions of metals belonging to Group 1 or Group 2 of the periodic table. Examples of the active material include positive electrode active materials and negative electrode active materials, as described below.

[0356] In the present invention, an inorganic solid electrolyte composition containing an active material (positive electrode active material or negative electrode active material) may be referred to as an electrode composition (positive electrode composition or negative electrode composition).

[0357] (Positive electrode active material)

[0358] The positive electrode active material is preferably one that can reversibly intercalate and deintercalate lithium ions. As long as the material has the aforementioned properties, there is no particular limitation. Examples include transition metal oxides that decompose the battery, or elements that can form complexes with lithium, such as sulfur.

[0359] Among them, as the positive electrode active material, it is preferred to use a transition metal oxide, more preferably a transition metal element M a (one or more elements selected from Co, Ni, Fe, Mn, Cu and V) transition metal oxide. In addition, the element M may be mixed into the transition metal oxide. b (Metals other than lithium, elements of Group 1 (Ia) and Group 2 (IIa) of the periodic table, Al, Ga, In, Ge, Sn, Pb, Sb, Bi, Si, P, and B, etc.) As a mixed amount, it is preferably 1:1 relative to the transition metal element M. a The amount of Li / M is preferably 0 to 30 mol%. a The synthesis is carried out by mixing the two components so that the molar ratio of the two components becomes 0.3 to 2.2.

[0360] Specific examples of transition metal oxides include (MA) transition metal oxides having a layered rock salt structure, (MB) transition metal oxides having a spinel structure, (MC) lithium-containing transition metal phosphate compounds, (MD) lithium-containing transition metal halophosphate compounds, and (ME) lithium-containing transition metal silicate compounds.

[0361] Specific examples of transition metal oxides (MA) having a layered rock salt structure include LiCoO2 (lithium cobalt oxide [LCO]), LiNi2O2 (lithium nickel oxide), LiNi 0.85 Co 0.10 Al 0.05 O2 (lithium nickel cobalt aluminum oxide [NCA]), LiNi 1 / 3 Co 1 / 3 Mn 1 / 3O2 (lithium nickel manganese cobalt oxide [NMC]) and LiNi 0.5 Mn 0.5 O2 (lithium manganese nickel oxide).

[0362] Specific examples of the transition metal oxide (MB) having a spinel structure include LiMn2O4 (LMO), LiCoMnO4, Li2FeMn3O8, Li2CuMn3O8, Li2CrMn3O8, and Li2NiMn3O8.

[0363] As (MC) lithium-containing transition metal phosphate compounds, for example, there can be mentioned olivine-type iron phosphate salts such as LiFePO4 and Li3Fe2(PO4)3, iron pyrophosphates such as LiFeP2O7, cobalt phosphates such as LiCoPO4, and monoclinic NASICON-type vanadium phosphate salts such as Li3V2(PO4)3 (lithium vanadium phosphate).

[0364] Examples of the (MD) lithium-containing transition metal halophosphate compound include iron fluorophosphates such as Li2FePO4F, manganese fluorophosphates such as Li2MnPO4F, and cobalt fluorophosphates such as Li2CoPO4F.

[0365] Examples of the (ME) lithium-containing transition metal silicate compound include Li 2 FeSiO 4 , Li 2 MnSiO 4 , and Li 2 CoSiO 4 .

[0366] In the present invention, (MA) is preferably a transition metal oxide having a layered rock salt structure, and more preferably LCO or NMC.

[0367] The shape of the positive electrode active material is not particularly limited, and is preferably in the form of particles. The particle size (volume average particle size) of the positive electrode active material is not particularly limited. For example, it can be set to 0.1 to 50 μm. The particle size of the positive electrode active material particles can be measured in the same manner as the particle size of the inorganic solid electrolyte. In order to make the positive electrode active material into a specified particle size, a conventional crusher 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 rotary airflow type jet mill or a sieve can be suitably used. During pulverization, wet pulverization in which a dispersion medium such as water or methanol coexists can also be appropriately performed. In order to set the desired particle size, classification is preferably performed. Classification is not particularly limited, and can be performed using a sieve, a wind classifier, etc. Both dry and wet classification can be used.

[0368] The positive electrode active material obtained by the calcination method may be used after washing with water, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent.

[0369] When the inorganic solid electrolyte-containing composition of the present invention contains a positive electrode active material, the positive electrode active material contained may be one kind or two or more kinds.

[0370] When forming a positive electrode active material layer, the positive electrode active material layer has a unit area (cm 2 The mass (mg) (weight per unit area) of the positive electrode active material is not particularly limited. It can be appropriately determined according to the designed battery capacity, for example, it can be set to 1 to 100 mg / cm 2 .

[0371] The content of the positive electrode active material in the inorganic solid electrolyte composition is not particularly limited, but is preferably 10 to 97 mass %, more preferably 30 to 95 mass %, further preferably 40 to 93 mass %, and particularly preferably 50 to 90 mass % based on 100 mass % of the solid content.

[0372] (Negative electrode active material)

[0373] The negative electrode active material is preferably one that can reversibly intercalate and deintercalate lithium ions. The material is not particularly limited as long as it has the aforementioned properties, and examples thereof include carbonaceous materials, metal oxides, metal composite oxides, lithium monomers, lithium alloys, and negative electrode active materials capable of forming alloys with lithium. Among these, carbonaceous materials, metal composite oxides, or lithium monomers are preferably used from the perspective of reliability.

[0374] The carbonaceous material used as the negative electrode active material refers to a material substantially composed of carbon. For example, carbon black such as petroleum pitch, acetylene black (AB), graphite (natural graphite, artificial graphite such as vapor-grown graphite), and various synthetic resins such as PAN (polyacrylonitrile) resin or furfuryl alcohol resin can be calcined to form a carbonaceous material. In addition, various carbon fiber types 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, mesophase microspheres, graphite whiskers and flat graphite can also be cited.

[0375] These carbonaceous materials are divided into difficult graphitization carbonaceous materials (also referred to as hard carbon) and graphite-based carbonaceous materials by the degree of graphitization. In addition, carbonaceous materials preferably have the surface spacing or density, crystallite size recorded in Japanese Patent Laid-Open No. 62-22066 Gazette, Japanese Patent Laid-Open No. 2-6856 Gazette, Japanese Patent Laid-Open No. 3-45473 Gazette. Carbonaceous material need not be a single material, and it is also possible to use the mixture of natural graphite and artificial graphite recorded in Japanese Patent Laid-Open No. 5-90844 Gazette, the graphite with coating layer recorded in Japanese Patent Laid-Open No. 6-4516 Gazette, etc.

[0376] As the carbonaceous material, hard carbon or graphite is preferably used, and graphite is more preferably used.

[0377] Oxides of metal or semimetal elements suitable for use as negative electrode active materials are not particularly limited as long as they are oxides capable of absorbing and releasing lithium. Examples include oxides of metal elements (metal oxides), composite oxides of metal elements, or composite oxides of metal elements and semimetal elements (collectively referred to as metal composite oxides), and oxides of semimetal elements (semimetal oxides). Preferred oxides are amorphous oxides, and further preferred are chalcogenides, which are reaction products of metal elements with elements from Group 16 of the periodic table. In the present invention, semimetal elements refer to elements exhibiting properties intermediate between those of metal elements and non-semimetal elements, typically including the six elements boron, silicon, germanium, arsenic, antimony, and tellurium, and further including the three elements selenium, polonium, and astatine. Furthermore, amorphous refers to materials having a broad scattering band with a vertex in the 2θ range of 20° to 40° as determined by X-ray diffraction using CuKα radiation, and may also have crystalline diffraction lines. The strongest intensity among the crystalline diffraction lines appearing in the region of 40° to 70° at 2θ values ​​is preferably 100 times or less, more preferably 5 times or less, the intensity of the diffraction line at the top of the broad scattering band appearing in the region of 20° to 40° at 2θ values, and particularly preferably a diffraction line without crystallinity.

[0378] Among the compound groups comprising the above-mentioned amorphous oxides and chalcogenides, amorphous oxides of semimetallic elements or the above-mentioned chalcogenides are more preferred, and (complex) oxides or chalcogenides comprising one element selected from Groups 13 (IIIB) to 15 (VB) of the periodic table (e.g., Al, Ga, Si, Sn, Ge, Pb, Sb, and Bi) or a combination of two or more thereof are particularly preferred. Specific examples of preferred amorphous oxides and chalcogenides include Ga2O3, GeO, PbO, PbO2, Pb2O3, Pb2O4, Pb3O4, Sb2O3, Sb2O4, Sb2O8Bi2O3, Sb2O8Si2O3, Sb2O5, Bi2O3, Bi2O4, GeS, PbS, PbS2, Sb2S3, or Sb2S5.

[0379] Preferred negative electrode active materials that can be used together with the amorphous oxides containing Sn, Si, or Ge as the core include carbonaceous materials capable of absorbing and / or releasing lithium ions or lithium metal, lithium alone, lithium alloys, and negative electrode active materials capable of alloying with lithium.

[0380] From the perspective of high current density charge and discharge characteristics, oxides of metal or semimetal elements, particularly metal (composite) oxides and the above-mentioned chalcogenides preferably contain at least one of titanium and lithium as a constituent component. Examples of metal composite oxides containing lithium (lithium composite metal oxides) include composite oxides of lithium oxide and the above-mentioned metal (composite) oxides or chalcogenides, and more specifically, Li2SnO2.

[0381] The negative electrode active material, such as metal oxide, preferably contains titanium element (titanium oxide). Specifically, due to Li4Ti5O 12 Lithium titanate (LTO) has a small volume change when absorbing and releasing lithium ions, and therefore has excellent rapid charge and discharge characteristics. It is preferred in terms of suppressing electrode degradation and extending the life of lithium-ion secondary batteries.

[0382] The lithium alloy used as the negative electrode active material is not particularly limited as long as it is an alloy commonly used as a negative electrode active material for secondary batteries. Examples thereof include lithium-aluminum alloys containing lithium as a base metal and 10% by mass of aluminum added thereto.

[0383] The negative electrode active material capable of forming an alloy with lithium is not particularly limited as long as it is a negative electrode active material commonly used as a secondary battery. This active material has a large expansion and contraction due to the charge and discharge of the all-solid-state secondary battery, and accelerates the reduction of the cycle characteristics. The all-solid-state secondary battery of the present invention is assembled with a layer consisting of the inorganic solid electrolyte composition of the present invention, so that the reduction of the cycle characteristics can be suppressed. As such an active material, there can be cited (negative electrode) active materials (alloys, etc.) with silicon or tin elements, each metal such as Al and In, preferably a negative electrode active material (active material containing silicon element) with silicon element that can achieve higher battery capacity, more preferably an active material containing silicon element having a silicon element content of more than 50 mol% of all constituent elements.

[0384] Generally, negative electrodes containing these negative electrode active materials (such as Si negative electrodes containing active materials containing silicon elements and Sn negative electrodes containing active materials containing tin elements) can absorb more Li ions than carbon negative electrodes (such as graphite and acetylene black). In other words, the amount of Li ions absorbed per unit mass increases. Therefore, the battery capacity can be increased. As a result, there is an advantage in being able to extend the battery driving time.

[0385] Examples of active materials containing silicon include silicon materials such as Si and SiOx (0 < x ≤ 1), and silicon-containing alloys (e.g., LaSi2, VSi2, La-Si, Gd-Si, Ni-Si) or organized active materials (e.g., LaSi2 / Si) containing titanium, vanadium, chromium, manganese, nickel, copper, lanthanum, and the like. Furthermore, active materials containing silicon and tin elements such as SnSiO3 and SnSiS3 can be cited. Furthermore, SiOx itself can be used as a negative electrode active material (semi-metallic oxide), and since Si is generated by the operation of an all-solid-state secondary battery, it can be used as a negative electrode active material (its precursor) that can be alloyed with lithium.

[0386] Examples of negative electrode active materials containing tin include Sn, SnO, SnO2, SnS, SnS2, and active materials containing the aforementioned silicon and tin elements. Furthermore, composite oxides with lithium oxide, such as Li2SnO2, are also exemplified.

[0387] In the present invention, the above-mentioned negative electrode active material can be used without particular limitation. However, from the viewpoint of battery capacity, as the negative electrode active material, it is preferred to use a negative electrode active material that can alloy with lithium, among which the above-mentioned silicon material or silicon-containing alloy (alloy containing silicon element) is more preferred, and it is further preferred to contain silicon (Si) or a silicon-containing alloy.

[0388] The measurement method can be inductively coupled plasma (ICP) emission spectrometry. As a simple method, the chemical formula of the compound obtained by the calcination method can be calculated from the mass difference of the powder before and after calcination.

[0389] The shape of the negative electrode active material is not particularly limited, but is preferably in the form of particles. The volume average particle size of the negative electrode active material is not particularly limited, but is preferably 0.1 to 60 μm. The volume average particle size of the negative electrode active material particles can be measured in the same manner as the particle size of the inorganic solid electrolyte described above. To achieve the desired particle size, a conventional pulverizer or classifier is used, as with the positive electrode active material.

[0390] When the inorganic solid electrolyte-containing composition of the present invention contains a negative electrode active material, the negative electrode active material contained may be one kind or two or more kinds.

[0391] When forming a negative electrode active material layer, the negative electrode active material layer has a unit area (cm 2 The mass (mg) (weight per unit area) of the negative electrode active material is not particularly limited. It can be appropriately determined according to the designed battery capacity, for example, it can be set to 1 to 100 mg / cm 2 .

[0392] The content of the negative electrode active material in the inorganic solid electrolyte composition is not particularly limited, but is preferably 10 to 90 mass %, more preferably 20 to 85 mass %, more preferably 30 to 80 mass %, and even more preferably 40 to 75 mass % based on 100 mass % of the solid content.

[0393] In the present invention, when the negative electrode active material layer is formed by charging the secondary battery, ions of metals belonging to Group 1 or Group 2 of the periodic table, which are generated within the all-solid-state secondary battery, can be used in place of the above-mentioned negative electrode active material. These ions are bonded to electrons and precipitated as metal, thereby forming the negative electrode active material layer.

[0394] (Coating of active substances)

[0395] The surfaces of the positive electrode active material and the negative electrode active material can also be coated with different metal oxides. As surface coating agents, metal oxides containing Ti, Nb, Ta, W, Zr, Al, Si or Li can be cited. Specifically, titanate spinel, tantalum oxides, niobium oxides, lithium niobate compounds, etc. can be cited. Specifically, Li4Ti5O 12, Li2Ti2O5, LiTaO3, LiNbO3, LiAlO2, Li2ZrO3, Li2WO4, Li2TiO3, Li2B4O7, Li3PO4, Li2MoO4, Li3BO3, LiBO2, Li2CO3, Li2SiO3, SiO2, TiO2, ZrO2, Al2O3, B2O3, etc.

[0396] Furthermore, the surface of the electrode including the positive electrode active material or the negative electrode active material may be surface-treated with sulfur or phosphorus.

[0397] Furthermore, the surface of the particles of the positive electrode active material or the negative electrode active material may be subjected to a surface treatment using actinic rays or active gas (plasma, etc.) before and after the surface coating.

[0398] <Conductive additives>

[0399] The inorganic solid electrolyte-containing composition of the present invention preferably contains a conductive additive. For example, a silicon atom-containing active material as a negative electrode active material is preferably used in combination with a conductive additive.

[0400] The conductive additive is not particularly limited, and generally known conductive additives can be used. For example, graphites such as natural graphite and artificial graphite, carbon blacks such as acetylene black (AB), Ketjen black, and furnace black, amorphous carbon such as needle coke, carbon fibers such as vapor-grown carbon fibers and carbon nanotubes, carbonaceous materials such as graphene and fullerene, and metal powders and metal fibers such as copper and nickel can be used. Conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene, and polyphenylene derivatives can also be used.

[0401] In the present invention, when an active material and a conductive aid are used in combination, among the conductive aids, those that do not produce the insertion and extraction of ions of metals belonging to Group 1 or Group 2 of the periodic table (preferably Li ions) when the battery is charged and discharged, and do not function as active materials, are considered conductive aids. Therefore, among the conductive aids, those that can function as active materials in the active material layer when the battery is charged and discharged are classified as active materials rather than conductive aids. Whether or not they function as active materials when the battery is charged and discharged is determined by the combination with the active material, rather than being determined in general.

[0402] The shape of the conductive auxiliary agent is not particularly limited, but is preferably in the form of particles.

[0403] When the inorganic solid electrolyte-containing composition of the present invention contains a conductive auxiliary agent, the conductive auxiliary agent contained may be one kind or two or more kinds.

[0404] When the inorganic solid electrolyte-containing composition contains a conductive auxiliary agent, the content of the conductive auxiliary agent in the inorganic solid electrolyte-containing composition is preferably 0 to 10% by mass based on 100% by mass of the solid content.

[0405] Lithium salts

[0406] The inorganic solid electrolyte-containing composition of the present invention preferably further contains a lithium salt (supporting electrolyte).

[0407] The lithium salt is preferably a lithium salt commonly used for this type of product, without particular limitation. For example, the lithium salts described in paragraphs 0082 to 0085 of JP-A-2015-088486 are preferred.

[0408] When the inorganic solid electrolyte-containing composition of the present invention includes a lithium salt, the content of the lithium salt is preferably 0.1 parts by mass or more, more preferably 5 parts by mass or more, relative to 100 parts by mass of the inorganic solid electrolyte. The upper limit is preferably 50 parts by mass or less, more preferably 20 parts by mass or less.

[0409] Dispersants

[0410] In the inorganic solid electrolyte composition of the present invention, the polymer binder also acts as a dispersant, so a dispersant other than the polymer binder may not be included. When the inorganic solid electrolyte composition contains a dispersant other than the polymer binder constituent, a dispersant commonly used in all-solid-state secondary batteries can be appropriately selected as the dispersant. Typically, the desired compound in particle adsorption, steric repulsion and / or electrostatic repulsion is appropriately used.

[0411] <Other additives>

[0412] The inorganic solid electrolyte composition of the present invention may appropriately contain an ionic liquid, a thickener, a crosslinking agent (a substance that undergoes a crosslinking reaction by free radical polymerization, polycondensation, or ring-opening polymerization), a polymerization initiator (a substance that generates acid or free radicals by heat or light), a defoaming agent, a leveling agent, a dehydrating agent, an antioxidant, and the like as ingredients other than the above-mentioned ingredients. The ionic liquid is a liquid included to further improve ionic conductivity, and any known liquid can be used without particular limitation. Furthermore, polymers other than the polymer forming the polymer binder may contain a commonly used binder.

[0413] (Preparation of Inorganic Solid Electrolyte-Containing Composition)

[0414] The inorganic solid electrolyte composition of the present invention can be prepared by conventional methods. Specifically, it can be prepared by mixing an inorganic solid electrolyte, a polymer binder, a dispersion medium, preferably a conductive additive, an appropriate lithium salt, and any other components using various commonly used mixers to prepare a mixture, preferably a slurry. In the case of an electrode composition, an active material is further mixed.

[0415] The mixing method is not particularly limited, and the mixing can be carried out using a known mixer such as a ball mill, a bead mill, a planetary mixer, a scraper mixer, a roll mill, a kneader, a disc mill, a rotation-revolution mixer, or a narrow gap disperser.

[0416] There is no particular limitation on the mixing conditions. For example, the rotation speed of a rotation-revolution mixer or the like can be set to 200 to 3000 rpm. The mixing atmosphere can be any atmosphere under atmospheric pressure, under dry air (dew point below -20°C), or in an inert gas (for example, argon, helium, or nitrogen). Since the inorganic solid electrolyte easily reacts with moisture, it is preferably mixed under dry air or in an inert gas.

[0417] [Sheet for all-solid-state secondary batteries]

[0418] The all-solid-state secondary battery sheet of the present invention is a sheet-like molded body capable of forming a constituent layer of an all-solid-state secondary battery, including various modes according to its use. For example, a sheet preferably used for a solid electrolyte layer (also referred to as a solid electrolyte sheet for an all-solid-state secondary battery), a sheet preferably used for a laminate of an electrode or an electrode and a solid electrolyte layer (electrode sheet for an all-solid-state secondary battery), etc. can be cited. In the present invention, these various sheets are collectively referred to as sheets for all-solid-state secondary batteries.

[0419] In the present invention, each layer constituting the sheet for an all-solid-state secondary battery may have a single-layer structure or a multi-layer structure.

[0420] <Solid electrolyte sheets for all-solid-state secondary batteries>

[0421] The solid electrolyte sheet for an all-solid-state secondary battery of the present invention may be a sheet having a solid electrolyte layer. It may be a sheet in which the solid electrolyte layer is formed on a substrate, or it may be a sheet formed of a solid electrolyte layer without a substrate. The solid electrolyte sheet for an all-solid-state secondary battery may also have other layers in addition to the solid electrolyte layer. Examples of other layers include a protective layer (release sheet), a current collector, and a coating.

[0422] Examples of the solid electrolyte sheet for an all-solid-state secondary battery of the present invention include a sheet having, on a substrate, a layer comprising the inorganic solid electrolyte composition of the present invention, a conventional solid electrolyte layer, and a protective layer in this order. The thickness of each layer constituting the solid electrolyte sheet for an all-solid-state secondary battery is the same as the thickness of each layer described below in the all-solid-state secondary battery.

[0423] The content of each component in the constituent layer is not particularly limited, and preferably has the same meaning as the content of each component in the solid content of the inorganic solid electrolyte-containing composition of the present invention.

[0424] As a substrate, there is no particular limitation as long as it is a substrate capable of supporting a solid electrolyte layer, and examples include sheet materials (plate-like bodies) such as the materials described in the collector described later, organic materials, and inorganic materials. As organic materials, various polymers can be mentioned, and specifically, polyethylene terephthalate, polypropylene, polyethylene, and cellulose can be mentioned. As inorganic materials, for example, glass and ceramics can be mentioned.

[0425] <Electrode sheets for all-solid-state secondary batteries>

[0426] The electrode sheet for an all-solid-state secondary battery of the present invention (also referred to as an "electrode sheet") can be an electrode sheet having an active material layer. It can be a sheet in which the active material layer is formed on a substrate (current collector), or a sheet formed of an active material layer without a substrate. The electrode sheet is generally a sheet having a substrate (current collector) and an active material layer, but also includes a form having a substrate (current collector), an active material layer, and a solid electrolyte layer in sequence, and a form having a substrate (current collector), an active material layer, a solid electrolyte layer, and an active material layer in sequence.

[0427] At least one of the solid electrolyte layer and active material layer possessed by the electrode sheet is formed by the inorganic solid electrolyte composition of the present invention. The content of each component in the solid electrolyte layer or active material layer formed by the inorganic solid electrolyte composition of the present invention is not particularly limited, and the preferred meaning is the same as the meaning of the content of each component in the solid component of the inorganic solid electrolyte composition (electrode composition) of the present invention. The thickness of each layer constituting the electrode sheet of the present invention is the same as the thickness of each layer described in the all-solid-state secondary battery described later. The electrode sheet of the present invention may have the above-mentioned other layers.

[0428] When the solid electrolyte layer or active material layer is not formed of the inorganic solid electrolyte composition of the present invention, it is formed of a common constituent layer forming material.

[0429] In the all-solid-state secondary battery sheet of the present invention, at least one layer in the solid electrolyte layer and the active material layer is formed by the inorganic solid electrolyte composition of the present invention, and has a constituent layer with a flat surface formed by firmly bonding solid particles to each other. Therefore, the all-solid-state secondary battery sheet of the present invention is used as the constituent layer of the all-solid-state secondary battery, thereby enabling the excellent cycle characteristics of the all-solid-state secondary battery. In particular, in the all-solid-state secondary battery electrode sheet and the all-solid-state secondary battery in which the active material layer is formed by the inorganic solid electrolyte composition of the present invention, the active material layer and the collector show firm adhesion, enabling further improvement in cycle characteristics. Therefore, the all-solid-state secondary battery sheet of the present invention is suitable for use as a sheet capable of forming the constituent layer of the all-solid-state secondary battery.

[0430] [Method for producing a sheet for all-solid-state secondary batteries]

[0431] The manufacturing method of the all-solid-state secondary battery sheet of the present invention is not particularly limited, and the above-mentioned layers can be formed using the inorganic solid electrolyte composition of the present invention. For example, it is preferred to cite a method of forming a layer (coating and drying layer) consisting of an inorganic solid electrolyte composition on a substrate or a collector (which can be via another layer). Thus, a sheet for an all-solid-state secondary battery with a substrate or a collector and a coating and drying layer can be made. In particular, when the inorganic solid electrolyte composition of the present invention is film-formed on the collector to make a sheet for an all-solid-state secondary battery, the close fit between the collector and the active material layer can be made firm. Here, the coating and drying layer refers to a layer formed by coating the inorganic solid electrolyte composition of the present invention and drying the dispersion medium (that is, a layer formed using the inorganic solid electrolyte composition of the present invention and removing the dispersion medium from the inorganic solid electrolyte composition of the present invention). As long as the active material layer and the coating and drying layer are within the range that does not damage the effect of the present invention, the dispersion medium can remain, and as a residual amount, for example, in each layer can be set to 3% by mass or less.

[0432] In the method for producing the sheet for an all-solid-state secondary battery of the present invention, each step such as coating and drying will be described below in the method for producing an all-solid-state secondary battery.

[0433] In the method for producing an all-solid-state secondary battery sheet of the present invention, the dried coated layer obtained in the above manner can also be pressed. The pressing conditions and the like will be described in the method for producing an all-solid-state secondary battery described later.

[0434] Furthermore, in the method for producing the sheet for an all-solid-state secondary battery of the present invention, the substrate, the protective layer (particularly the release sheet), and the like can also be peeled off.

[0435] [All-solid-state secondary battery]

[0436] The all-solid-state secondary battery of the present invention has a positive electrode active material layer, a negative electrode active material layer opposite to 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. The all-solid-state secondary battery of the present invention is not particularly limited as long as it has a structure with a solid electrolyte layer between the positive electrode active material layer and the negative electrode active material layer. For example, a known structure related to an all-solid-state secondary battery can be adopted. In a preferred all-solid-state secondary battery, the positive electrode active material layer is laminated on the surface of the side opposite to the solid electrolyte layer to form a positive electrode, and the negative electrode active material layer is laminated on the surface of the side opposite to the solid electrolyte layer to form a negative electrode. In the present invention, each constituent layer (including a collector, etc.) constituting the all-solid-state secondary battery can be a single-layer structure or a multi-layer structure.

[0437] In the all-solid-state secondary battery of the present invention, at least one of the negative electrode active material layer, the positive electrode active material layer and the solid electrolyte layer is a layer formed by the inorganic solid electrolyte composition of the present invention, showing excellent cycle characteristics. From the viewpoint of further improving the cycle characteristics, the all-solid-state secondary battery of the present invention preferably has at least two layers in the negative electrode active material layer, the positive electrode active material layer and the solid electrolyte layer formed by the inorganic solid electrolyte composition of the present invention, and more preferably all layers of the negative electrode active material layer, the positive electrode active material layer and the solid electrolyte layer are layers formed by the inorganic solid electrolyte composition of the present invention. In the present invention, the constituent layer of the all-solid-state secondary battery formed by the inorganic solid electrolyte composition of the present invention refers to a method of forming a constituent layer comprising a sheet for an all-solid-state secondary battery of the present invention (wherein, when there is a layer other than a layer formed by the inorganic solid electrolyte composition of the present invention, the sheet obtained by removing the layer) is preferably formed by the inorganic solid electrolyte composition of the present invention. For the types of components contained and their contents, the active material layer or solid electrolyte layer formed by the inorganic solid electrolyte composition of the present invention is preferably the same as that in the solid component of the inorganic solid electrolyte composition of the present invention.

[0438] Active material layer and solid electrolyte layer

[0439] The thickness of the negative electrode active material layer, solid electrolyte layer, and positive electrode active material layer is not particularly limited. Considering the dimensions of typical all-solid-state secondary batteries, the thickness of each layer is preferably 10 to 1,000 μm, more preferably 20 μm or greater and less than 500 μm. In the all-solid-state secondary battery of the present invention, the thickness of at least one of the positive electrode active material layer and the negative electrode active material layer is further preferably 50 μm or greater and less than 500 μm.

[0440] When the active material layer or the solid electrolyte layer is not formed of the inorganic solid electrolyte composition of the present invention, a known material can be used.

[0441] <Current Collector>

[0442] The positive electrode current collector and the negative electrode current collector are preferably electron conductors.

[0443] In the present invention, either the positive electrode current collector or the negative electrode current collector, or both of them together, may be simply referred to as a current collector.

[0444] As materials for forming the positive electrode current collector, in addition to aluminum, aluminum alloys, stainless steel, nickel and titanium, preferred are materials obtained by treating the surface of aluminum or stainless steel with carbon, nickel, titanium or silver (materials forming a thin film), among which aluminum and aluminum alloys are more preferred.

[0445] As the material forming the negative electrode collector, in addition to aluminum, copper, copper alloys, stainless steel, nickel and titanium, it is preferred to treat the surface of aluminum, copper, copper alloys or stainless steel with carbon, nickel, titanium or silver, and more preferably aluminum, copper, copper alloys and stainless steel.

[0446] The current collector is generally in the form of a film, but a mesh, a perforated body, a lath body, a porous body, a foamed body, a molded body of a fiber group, or the like can also be used.

[0447] The thickness of the current collector is not particularly limited, but is preferably 1 to 500 μm. Furthermore, it is also preferred to provide irregularities on the surface of the current collector by surface treatment.

[0448] <Other structures>

[0449] In the present invention, functional layers or components may be appropriately inserted or disposed between or outside the negative electrode current collector, negative electrode active material layer, solid electrolyte layer, positive electrode active material layer, and positive electrode current collector.

[0450] <Housing>

[0451] The all-solid-state secondary battery of the present invention can be used as an all-solid-state secondary battery in the state of the above structure according to the application, but in order to make it into the form of a dry cell, it is preferably further enclosed in an appropriate shell for use. The shell can be a metallic shell or a shell made of resin (plastic). In the case of using a metallic shell, for example, a shell made of aluminum alloy or stainless steel can be cited. Preferably, the metallic shell is divided into a positive electrode side shell and a negative electrode side shell and is electrically connected to the positive electrode collector and the negative electrode collector, respectively. Preferably, the shell on the positive electrode side and the shell on the negative electrode side are joined and integrated with a short circuit prevention gasket.

[0452] Below, reference Figure 1 , an all-solid-state secondary battery according to a preferred embodiment of the present invention will be described, but the present invention is not limited thereto.

[0453] Figure 1 This 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. When viewed from the negative electrode side, the all-solid-state secondary battery 10 of this embodiment has a negative electrode 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 collector 5 in this order. Each layer is in contact with each other and has an adjacent structure. By adopting such a structure, electrons (e) are supplied to the negative electrode side during charging. - ) and accumulate lithium ions (Li + On the other hand, during discharge, the lithium ions (Li + ) returns to the positive electrode side and supplies electrons to the working portion 6. In the example shown in the figure, a bulb is used as a model in the working portion 6, and the bulb is lit by discharge.

[0454] In will have Figure 1 When the all-solid-state secondary battery with the layer structure shown is placed in a 2032-type button-type battery box, the all-solid-state secondary battery is sometimes also referred to as a laminate for an all-solid-state secondary battery, and the battery made by placing the all-solid-state secondary battery laminate in a 2032-type button-type battery box is called a (button-type) all-solid-state secondary battery.

[0455] (Positive electrode active material layer, solid electrolyte layer, negative electrode active material layer)

[0456] In the all-solid-state secondary battery 10, the positive electrode active material layer, solid electrolyte layer, and negative electrode active material layer are all formed from the inorganic solid electrolyte composition of the present invention. This all-solid-state secondary battery 10 exhibits excellent battery performance. The inorganic solid electrolyte and polymer binder contained in the positive electrode active material layer 4, solid electrolyte layer 3, and negative electrode active material layer 2 can be of the same or different types.

[0457] In the present invention, either or both of the positive electrode active material layer and the negative electrode active material layer are referred to as the active material layer or the electrode active material layer. Furthermore, either or both of the positive electrode active material and the negative electrode active material are collectively referred to as the active material or the electrode active material.

[0458] In the present invention, when the constituent layers are formed from the inorganic solid electrolyte-containing composition of the present invention, an all-solid-state secondary battery having excellent cycle characteristics can be realized.

[0459] 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, lithium foil, and a lithium vapor-deposited film. The thickness of the lithium metal layer is independent of the thickness of the negative electrode active material layer and can be, for example, 1 to 500 μm.

[0460] (Current Collector)

[0461] The positive electrode current collector 5 and the negative electrode current collector 1 are respectively as described above.

[0462] When the all-solid-state secondary battery 10 has a constituent layer other than the constituent layer formed of the inorganic solid electrolyte composition of the present invention, a layer formed of a known constituent layer-forming material can also be used.

[0463] Furthermore, each layer may be configured as a single layer or as a multi-layer structure.

[0464] [Manufacturing of all-solid-state secondary batteries]

[0465] The all-solid-state secondary battery can be manufactured by conventional methods. Specifically, the all-solid-state secondary battery can be manufactured by forming the above-mentioned layers using the inorganic solid electrolyte composition of the present invention. This will be described in detail below.

[0466] The all-solid-state secondary battery of the present invention can be manufactured by a method (the method for manufacturing a sheet for an all-solid-state secondary battery of the present invention) comprising (via) a step of appropriately applying the inorganic solid electrolyte composition of the present invention on a substrate (for example, a metal foil serving as a current collector) to form a coating film (film formation).

[0467] For example, an inorganic solid electrolyte composition containing a positive electrode active material as a positive electrode material (positive electrode composition) is applied to a metal foil as a positive electrode collector to form a positive electrode active material layer to produce a positive electrode sheet for an all-solid-state secondary battery. Next, a solid electrolyte layer is formed by applying an inorganic solid electrolyte composition for forming a solid electrolyte layer on the positive electrode active material layer. In addition, a negative electrode active material layer is formed by applying an inorganic solid electrolyte composition containing a negative electrode active material as a negative electrode material (negative electrode composition) on the solid electrolyte layer. By overlapping the negative electrode collector (metal foil) on the negative electrode active material layer, an all-solid-state secondary battery with a structure in which a solid electrolyte layer is sandwiched between the positive electrode active material layer and the negative electrode active material layer can be obtained. It can also be sealed in a shell as a desired all-solid-state secondary battery.

[0468] Furthermore, in contrast to the method of forming each layer, an all-solid-state secondary battery can be manufactured by forming a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer on a negative electrode current collector and then stacking the positive electrode current collector.

[0469] As another method, the following method can be cited. That is, a positive electrode sheet for an all-solid-state secondary battery is produced as described above. Furthermore, an inorganic solid electrolyte composition containing a negative electrode active material as a negative electrode material (negative electrode composition) is applied to a metal foil serving as a negative electrode collector to form a negative electrode active material layer to produce a negative electrode sheet for an all-solid-state secondary battery. Next, a solid electrolyte layer is formed on the active material layer of any one of these sheets as described above. Furthermore, another of the positive electrode sheet for an all-solid-state secondary battery and the negative electrode sheet for an all-solid-state secondary battery are stacked on the solid electrolyte layer in such a manner that the solid electrolyte layer is in contact with the active material layer. In this way, an all-solid-state secondary battery can be manufactured.

[0470] Furthermore, as another method, the following method can be cited. That is, a positive electrode sheet for an all-solid-state secondary battery and a negative electrode sheet for an all-solid-state secondary battery are prepared as described above. Furthermore, in addition to this, a solid electrolyte sheet for an all-solid-state secondary battery consisting of a solid electrolyte layer is prepared by applying an inorganic solid electrolyte composition to a substrate. Furthermore, the solid electrolyte layer peeled off from the substrate is sandwiched between the positive electrode sheet for an all-solid-state secondary battery and the negative electrode sheet for an all-solid-state secondary battery. In this way, an all-solid-state secondary battery can be manufactured.

[0471] The solid electrolyte layer and the like are formed, for example, by pressure-molding an inorganic solid electrolyte composition and the like on a substrate or an active material layer under pressure conditions described later.

[0472] In the above-mentioned production method, the inorganic solid electrolyte-containing composition of the present invention may be used in any of the positive electrode composition, the inorganic solid electrolyte-containing composition, and the negative electrode composition, or in any of the compositions.

[0473] <Formation of each layer (film formation)>

[0474] The method for coating the inorganic solid electrolyte composition is not particularly limited and can be appropriately selected, and examples thereof include wet coating methods such as spray coating, spin coating, dip coating, slit coating, stripe coating, and bar coating.

[0475] At this time, the inorganic solid electrolyte composition can be dried (heat treated) after being coated separately, or it can be dried after multi-layer coating. The drying temperature is not particularly limited as long as the dispersion medium can be removed, and is appropriately set according to the boiling point of the dispersion medium. For example, the lower limit of the drying temperature is preferably above 30°C, more preferably above 60°C, and further preferably above 80°C. The upper limit is preferably below 300°C, more preferably below 250°C, and further preferably below 200°C. By heating within such a temperature range, the dispersion medium can be removed to obtain a solid state (coating dry layer). Moreover, the temperature will not be too high and the various components of the all-solid-state secondary battery will not be damaged, so it is preferred. Thus, in the all-solid-state secondary battery, excellent overall performance is exhibited and good coating suitability (adhesion) and good ion conductivity without pressurization can be obtained.

[0476] As described above, when the inorganic solid electrolyte-containing composition of the present invention is applied and dried, it is possible to suppress variations in contact state and to bond solid particles, and to form a coated and dried layer having a flat surface.

[0477] It is preferred that after applying the inorganic solid electrolyte composition, after stacking the constituent layers, or after producing the all-solid-state secondary battery, each layer or the all-solid-state secondary battery is pressurized. Furthermore, it is also preferred that the pressurization be performed while the layers are stacked. Examples of pressurization methods include hydraulic cylinder presses and the like. The pressurization force is not particularly limited, but is generally preferably in the range of 5 to 1500 MPa.

[0478] Furthermore, the applied inorganic solid electrolyte composition can be heated while being pressurized. The heating temperature is not particularly limited, but is generally in the range of 30°C to 300°C. Pressing can also be performed at a temperature higher than the glass transition temperature of the inorganic solid electrolyte. Furthermore, pressing can also be performed at a temperature higher than the glass transition temperature of the polymer constituting the polymer binder. However, the temperature is typically set to a value not exceeding the melting point of the polymer.

[0479] The pressurization may be performed in a state where the coating solvent or dispersion medium has been dried in advance, or may be performed in a state where the solvent or dispersion medium remains.

[0480] Furthermore, the compositions may be applied simultaneously, or applied, dried, and pressed simultaneously and / or sequentially. The compositions may be applied to respective substrates and then laminated by transfer.

[0481] The environment during coating or pressurization is not particularly limited and may be any environment such as atmospheric pressure, dry air (dew point -20°C or lower), or inert gas (e.g., argon, helium, or nitrogen).

[0482] The pressing time can be a short time (e.g., within a few hours) to apply high pressure, or a long time (more than 1 day) to apply moderate pressure. In addition to the sheet for all-solid-state secondary batteries, for example, in the case of all-solid-state secondary batteries, it is possible to use the restraining tools (screw tightening pressure, etc.) of the all-solid-state secondary battery to continuously apply moderate pressure.

[0483] The punching pressure may be uniform or varied relative to the pressure receiving portion such as the sheet surface.

[0484] The pressing pressure can be changed according to the area of ​​the pressure receiving portion or the film thickness. In addition, the pressure can be changed in stages to different levels on the same portion.

[0485] The stamping surface can be smooth or rough.

[0486] Initialization

[0487] The all-solid-state secondary battery manufactured in the above manner is preferably initialized after manufacturing or before use. There are no particular restrictions on initialization. For example, initial charge and discharge can be performed under increased pressing pressure, and then the pressure can be released until the normal operating pressure of the all-solid-state secondary battery is reached.

[0488] [Applications of all-solid-state secondary batteries]

[0489] The all-solid-state secondary battery of the present invention can be applied to a variety of purposes. There is no particular limitation on the applicable mode. For example, when it is mounted on an electronic device, a notebook computer, a pen-input computer, a mobile computer, an e-book reader, a mobile phone, a wireless telephone, a pager, a handheld terminal, a portable fax machine, a portable copier, a portable printer, a stereo headset, a camcorder, an LCD TV, a portable vacuum cleaner, a portable CD, a small disk, an electric shaver, a transceiver, an electronic notepad, a calculator, a memory card, a portable recorder, a radio, a backup power supply, etc. can be cited as other civilian products. Examples include automobiles (electric vehicles), electric vehicles, motors, lighting fixtures, toys, game consoles, load regulators, clocks, flashlights, cameras, and medical equipment (pacemakers, hearing aids, and shoulder massagers, etc.). Furthermore, it can be used as various military supplies and aviation supplies. Furthermore, it can also be combined with solar cells.

[0490] Example

[0491] The present invention will be described in further detail below with reference to the Examples, but the present invention is not limited thereto and should not be construed. In the following Examples, "parts" and "%" representing the composition are by mass unless otherwise specified. In the present invention, "room temperature" refers to 25°C.

[0492] 1. Polymer Synthesis

[0493] The polymer represented by the following chemical formula was synthesized as follows.

[0494] [Synthesis Example 1: Synthesis of Polymer B-1]

[0495] In a nitrogen-purged and dried pressure vessel, 300 g of cyclohexane as a solvent and 1.0 mL of sec-butyllithium (1.3 M, manufactured by FUJIFILM Wako Pure Chemical Corporation) as a polymerization initiator were placed. After heating to 50°C, 27.4 g of styrene was added and polymerization was carried out for 2 hours. Subsequently, 22.0 g of 1,3-butadiene and 20.7 g of ethylene were added and polymerization was carried out for 3 hours. Then, 27.4 g of styrene was added and polymerization was carried out for 2 hours. The obtained solution was reprecipitated in methanol, and the obtained solid was dried. To 100 parts by mass of the polymer obtained, 3 parts by mass of 2,6-di-tert-butyl-p-cresol and 2.5 g of maleic anhydride were added, and the reaction was carried out at 180°C for 5 hours. The obtained solution was reprecipitated in acetonitrile, and the obtained solid was dried at 80°C to obtain a polymer (dried solid). Next, the entire amount of the obtained polymer was dissolved in 400 parts by mass of cyclohexane in a pressure-resistant container. Then, 5% by mass of palladium on carbon (palladium loading: 5% by mass) was added to the polymer as a hydrogenation catalyst. The reaction was carried out under a hydrogen pressure of 2 MPa and 150°C for 10 hours. After cooling and depressurization, the palladium on carbon was removed by filtration, and the filtrate was concentrated and vacuum-dried to obtain Binder Precursor A.

[0496] Into a 1L three-necked flask equipped with a reflux cooling tube and a gas inlet plug, 450 parts by mass of xylene (manufactured by FUJIFILM Wako Pure Chemical Corporation) and 50 parts by mass of the above-mentioned adhesive precursor A were placed and dissolved. Then, 2 parts by mass of 1H,1H,2H,2H-perfluoro-1-octanol (manufactured by FUJIFILM Wako Pure Chemical Corporation) were added, the temperature was raised to 130°C, and stirring was continued for 20 hours. Then, it was added dropwise to methanol to obtain SEBS polymer (adhesive) B-1 as a precipitate. After drying under reduced pressure at 60°C for 5 hours, it was dissolved in butyl butyrate. In this way, polymer B-1 with a mass average molecular weight of 99,000 was synthesized, and adhesive solution B-1 (concentration 10% by mass) composed of polymer B-1 was obtained.

[0497] In polymer B-1, the content of the constituent components having a functional group selected from the functional group group (a) other than styrene, ethylene and butene was 1.5 mol% of a fluoroalkyl group and 1.5 mol% of a carboxyl group, for a total of 3.0 mol%.

[0498] [Synthesis Example 2: Synthesis of Adhesive B-2]

[0499] To an autoclave were added 200 parts by mass of ion-exchanged water, 96 parts by mass of vinylidene fluoride, 60 parts by mass of hexafluoropropylene, and 44 parts by mass of tetrafluoroethylene. One part by mass of diisopropyl peroxydicarbonate was also added, and the mixture was stirred at 30°C for 24 hours. After completion of polymerization, the precipitate was filtered and dried at 100°C for 10 hours to obtain polymer (binder) B-2. The obtained polymer B-2 was a random copolymer with a mass average molecular weight of 68,000.

[0500] The obtained polymer B-2 was dissolved in butyl butyrate to obtain a solution B-2 (concentration: 10% by mass) of a binder composed of the polymer B-2.

[0501] [Synthesis Example 3: Synthesis of Adhesive B-3]

[0502] To a 100 mL volumetric flask, 1.6 g of acrylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), 98.4 g of lauryl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), and 0.36 g of polymerization initiator V-601 (trade name, manufactured by Fujifilm Wako Pure Chemical Corporation) were added and dissolved in 36 g of butyl butyrate to prepare a monomer solution. To a 300 mL three-necked flask, 18 g of butyl butyrate was added dropwise with stirring at 80°C for 2 hours. After the dropwise addition was completed, the mixture was heated to 90°C and stirred for 2 hours to synthesize polymer B-3 (methacrylic acid polymer). The resulting solution was reprecipitated in methanol and redissolved in butyl butyrate to obtain solution B-3 (concentration 10% by mass), a binder composed of polymer B-3.

[0503] [Synthesis Example 4: Synthesis of Adhesive B-15]

[0504] In Synthesis Example 3, a compound for introducing each constituent component was used to make the polymer B-15 have a composition (content of the constituent components) represented by the following structural formula. In addition, the polymer B-15 was synthesized in the same manner as in Synthesis Example 3 to obtain a solution B-15 (concentration 10% by mass) of an adhesive composed of the polymer B-15.

[0505] [Synthesis Examples 5 to 14: Synthesis of Adhesives B-4 to B-13]

[0506] In Synthesis Example 3, instead of acrylic acid and dodecyl acrylate, AS-6 (trade name, styrene macromonomer, number average molecular weight 6000, manufactured by Toagosei Company, Limited), maleic anhydride, and dodecyl acrylate were used in the amounts described in Table A below, and the polymerization initiator V-601 (trade name, manufactured by FUJIFILM Wako Pure Chemical Corporation) was used in the amounts described in Table A below. In addition, polymers (binders) B-4 to B-13 were synthesized, and butyl butyrate solutions (concentration 10% by mass) of the binders B-4 to B-13 were obtained.

[0507] In the following Table A, the unit of the blending amount of each monomer component and V-601 is "g", and the unit of the blending amount ratio of each monomer component is "mol %".

[0508] [Table A]

[0509]

[0510] [Synthesis Example 15: Preparation of Adhesive B-14]

[0511] An epoxide of a styrene-butadiene block copolymer (trade name: EPOPLANT AT501, manufactured by Daicel Corporation) was dissolved in butyl butyrate to obtain a butyl butyrate solution (concentration: 10% by mass) of the adhesive B-14.

[0512] [Synthesis Example 16: Preparation of Adhesive B-16]

[0513] An ethylene-acrylate-glycidyl acrylate copolymer (trade name: BondFast BF-7M, manufactured by SUMITOMO CHEMICAL COMPANY, LIMITED) was dissolved in butyl butyrate to obtain a butyl butyrate solution (concentration: 10% by mass) of the adhesive B-16.

[0514] [Synthesis Example 17: Synthesis of Adhesive B-17]

[0515] In Synthesis Example 3, except that 37.7 g of butyl acrylate and 62.3 g of styrene were used instead of acrylic acid and dodecyl acrylate, polymer (binder) B-17 was synthesized in the same manner to obtain a butyl butyrate solution of Binder B-17 (concentration: 10 mass %).

[0516] [Synthesis Example 18: Synthesis of Adhesive T-1] (Acrylic Latex (Non-Dissolving Adhesive))

[0517] Adhesive B-3 described in Table 1 of Patent Document 1 (Japanese Patent Application Laid-Open No. 2015-088486) was synthesized in the same manner as the synthesis of Adhesive B-1 described in paragraphs

[0123] and

[0124] of Patent Document 1. Specifically, as monomer components, 20 parts by mass of methyl acrylate, 80 parts by mass of polyethylene glycol monomethyl ether acrylate (average number of ethylene glycol repeats: 9), and 11 parts by mass of the following macromonomer M-1 were used to synthesize polymer (adhesive) T-1 (equivalent to Adhesive B-3 in Patent Document 1), thereby obtaining a butyl butyrate solution of Adhesive T-1 (concentration: 10% by mass).

[0518] [Chemical Formula 6]

[0519]

[0520] [Synthesis Example 19: Preparation of Adhesive T-2] (Urethane Latex (Non-Dissolving Adhesive))

[0521] ART PEARL MM-101SMA (trade name, manufactured by Negami Chemical Industrial Co., Ltd.) was dispersed in butyl butyrate to obtain a butyl butyrate dispersion of the adhesive T-2 (concentration: 10% by mass).

[0522] [Synthesis Example 20: Preparation of Adhesive T-3] (Hydrocarbon Latex (Non-Dissolving Adhesive))

[0523] Flo-Beads (trade name, polyethylene-acrylic acid copolymer powder, manufactured by Sumitomo Seika Chemicals Company, Limited.) was dispersed in butyl butyrate to obtain a butyl butyrate dispersion of the adhesive T-3 (concentration: 10% by mass).

[0524] [Synthesis Example 21: Preparation of Adhesive T-4] (Fluorine-based Latex (Non-soluble Adhesive))

[0525] MicroDispers-200 (trade name, manufactured by TECHNO CHEMICAL Corp.) was dispersed in butyl butyrate to obtain a butyl butyrate dispersion of the adhesive T-4 (concentration: 10% by mass).

[0526] [Synthesis Example 22: Synthesis of Adhesives B-18 to B-24]

[0527] In Synthesis Example 3, polymers B-18 to B-24 were synthesized in the same manner as in Synthesis Example 3 except that a compound in which each constituent component had a structure and composition (content of constituent component) represented by the following structural formula was introduced instead of acrylic acid and dodecyl acrylate, and the amount of polymerization initiator V-601 (trade name, manufactured by FUJIFILM Wako Pure Chemical Corporation) was appropriately changed to adjust the molecular weight. Using the dispersion media described in the following table, binder solutions B-18 to B-24 (concentration 10% by mass) composed of polymers B-18 to B-24 were obtained.

[0528] [Synthesis Example 23: Synthesis of Adhesive B-25]

[0529] To a 200 mL volumetric flask, 1.0 g of maleic anhydride (manufactured by FUJIFILM Wako Pure Chemical Corporation), 99.0 g of dodecyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), and 0.06 g of polymerization initiator V-601 (trade name, manufactured by FUJIFILM Wako Pure Chemical Corporation) were added and dissolved in 36 g of butyl butyrate to prepare a monomer solution. 30 g of butyl butyrate was added to a 500 mL three-necked flask and the monomer solution was added dropwise with stirring at 80°C for 2 hours. After the addition was completed, the temperature was raised to 90°C and stirred for 2 hours. Then, after cooling to 60°C, butyl butyrate was added to a solid content of 30%, 80 g of methanol was added, and the mixture was stirred at 60°C for 1 hour. The obtained solution was reprecipitated in acetonitrile and redissolved in butyl butyrate to obtain a binder solution B-25 (concentration 10% by mass) composed of polymer B-25.

[0530] The following lists the synthesized polymers. The numbers written to the lower right of each component indicate the content (mol%). In the following structural formulas, Me represents a methyl group.

[0531] [Chemical Formula 7]

[0532]

[0533] [Chemical Formula 8]

[0534]

[0535] B-25

[0536]

[0537] The mass average molecular weight (Mw) and SP value of each synthesized polymer (binder) were calculated according to the aforementioned method. The dispersion component and polar component of the surface energy of each polymer (binder), as well as the adsorption rate to the inorganic solid electrolyte, were calculated according to the method described below. These results are shown in Table 1.

[0538] In addition, regarding the combinations of binder and dispersion medium used to prepare the inorganic solid electrolyte-containing compositions described in Tables 1-1 to 1-4 below, the solubility of each synthesized polymer in the dispersion medium determined by the transmittance measurement described above was 10% by mass or more.

[0539] 2. Synthesis of sulfide-based inorganic solid electrolytes

[0540] [Synthesis Example A]

[0541] The sulfide-based inorganic solid electrolyte was synthesized with reference to the non-patent literature of T. Ohtomo, A. Hayashi, M. Tatsumisago, Y. Tsuchida, S. Hama, K. Kawamoto, Journal of Power Sources, 233, (2013), pp231-235 and A. Hayashi, S. Hama, H. Morimoto, M. Tatsumisago, T. Minami, Chem. Lett., (2001), pp872-873.

[0542] Specifically, in an argon atmosphere (dew point -70°C) in a glove box, 2.42g of lithium sulfide (Li2S, manufactured by Aldrich, Inc., purity >99.98%) and 3.90g of phosphorus pentasulfide (P2S5, manufactured by Aldrich, Inc., purity >99%) were weighed, placed in an agate mortar, and mixed for 5 minutes using an agate pestle. The mixing ratio of Li2S and P2S5 was set to 75:25 on a molar basis.

[0543] Next, 66 g of 5 mm diameter zirconia beads were placed in a 45 mL zirconia container (manufactured by Fritsch Co., Ltd.), along with the total amount of the lithium sulfide and phosphorus pentasulfide mixture described above. The container was completely sealed under an argon atmosphere. The container was placed in a planetary ball mill P-7 (trade name, manufactured by Fritsch Co., Ltd.) and mechanically milled at 510 rpm at 25°C for 36 hours to obtain 6.20 g of a yellow powdered sulfide-based inorganic solid electrolyte (Li-PS-based glass, hereinafter sometimes referred to as LPS). The particle size of the Li-PS-based glass was 4 μm.

[0544] [Example 1]

[0545] <Preparation of Inorganic Solid Electrolyte-Containing Composition (Slurry)>

[0546] In a container for a rotating-revolving mixer (ARE-310, manufactured by THINKY CORPORATION), 2.8 g of LPS synthesized in Synthesis Example A, 0.08 g (solid content weight) of the binder solution prepared above, and the dispersion medium listed in the following table were placed so that the dispersion medium content in the composition was 50% by mass. The container was then placed in the rotating-revolving mixer ARE-310 (trade name), manufactured by THINKY CORPORATION. Mixing was carried out at 25°C and a rotation speed of 2000 rpm for 5 minutes to prepare inorganic solid electrolyte-containing compositions (slurries) S-1 to S-34, respectively.

[0547] The contents of the components in the composition were 97.2% by mass of LPS and 2.8% by mass of the binder per 100% by mass of the solid content. Compositions S-17 and S-21 to S-24 contained two binders at a mass ratio of 50:50.

[0548] <Preparation of positive electrode composition (slurry)>

[0549] 2.8 g of LPS synthesized in the above-mentioned Synthesis Example A and the dispersion medium described in the following table were added to a container of a rotation-revolution mixer (ARE-310, manufactured by THINKY CORPORATION) so that the content of the dispersion medium in the positive electrode composition became 50% by mass. Then, the container was placed in a rotation-revolution mixer ARE-310 (trade name) manufactured by THINKY CORPORATION and mixed for 2 minutes at a temperature of 25° C. and a rotation speed of 2000 rpm. Then, LiNi as a positive electrode active material was added to the container. 1 / 3 Co 1 / 3 Mn 1 / 3 13.2 g of O2 (NMC, manufactured by Aldrich, CO.LTD.), 0.32 g of acetylene black (AB) as a conductive additive, and 0.16 g of the binder solution prepared above (solid content mass) were placed in a rotation-revolution mixer ARE-310 and mixed at 25°C and a rotation speed of 2000 rpm for 2 minutes to prepare positive electrode compositions (slurries) P-1 to P-20, respectively.

[0550] The content of each component in the composition was 17.0 mass % of LPS, 80.1 mass % of NMC, 1.0 mass % of binder, and 1.9 mass % of AB based on 100 mass % of the solid content.

[0551] <Preparation of negative electrode composition (slurry)>

[0552] In a container of a rotating-orbital mixer (ARE-310, manufactured by THINKY CORPORATION), 2.8 g of LPS synthesized in Synthesis Example A, 0.08 g (solid content) of the binder solution prepared above, and the dispersion medium listed in the following table were placed so that the dispersion medium content in the negative electrode composition was 50% by mass. The container was then placed in the rotating-orbital mixer ARE-310 (trade name), manufactured by THINKY CORPORATION, and mixed at 25°C and 2000 rpm for 2 minutes. Next, 3.53 g of silicon (Si, manufactured by Aldrich) as the negative electrode active material and 0.27 g of carbon nanotubes VGCF (trade name, manufactured by SHOWA DENKO KK) as the conductive additive were added. The mixture was also placed in the rotating-orbital mixer ARE-310 (trade name) and mixed at 25°C and 2000 rpm for 2 minutes to prepare negative electrode compositions (slurries) N-1 to N-22.

[0553] The content of each component in the composition was 42.0 mass% of LPS, 52.8 mass% of Si, 1.2 mass% of binder, and 4.0 mass% of VGCF per 100 mass% solids. Compositions N-7 to N-9 and N-19 to N-21 were prepared using 3.53 g of graphite (Gr, manufactured by Hohsen Corp.) in place of silicon.

[0554] The types of binders used for each of the prepared compositions are shown in Table 1. The dispersion component and polar component of the surface energy of the active material, inorganic solid electrolyte, and binder, and the R SE 、R AM 、R AM +R SE The summary is shown in Table 1.

[0555] In addition, No. S-1 to S-3, S-5 to S-15, S-17, S-19, S-21 to S-34, P-1, P-2, P-4 to P-9, P-11 to P-20, N-1, N-3 to N-5, N-7, N-8 and N-10 to N-22 are inorganic solid electrolyte compositions of the present invention, and No. S-4, S-16, S-18, S-20, P-3, P-10, N-2, N-6, and N-9 are inorganic solid electrolyte compositions for comparison.

[0556] <Methods for measuring surface energy (surface energy of inorganic solid electrolytes and active materials)>

[0557] The measurement was performed using a powder contact angle measurement kit with a high-precision surface tensiometer DY-700 (trade name, manufactured by Kyowa Interface Science Co., Ltd.) as an option.

[0558] Specifically, 2.0 g of powder (inorganic solid electrolyte or active material) was placed in a 1 cm diameter cylinder, and the powder was compressed and filled using a cylindrical rod having the same diameter as the inner diameter of the cylinder. The above cylinder was set on the above powder contact angle measurement kit, and three solvents (hexadecane, ethylene glycol, or bromonaphthalene) were allowed to penetrate for 5 minutes, and W was measured. 2 W represents the permeation weight, and t represents the time. The contact angle cosθ is calculated according to the following Washburn equation. ε represents the porosity, and r represents the capillary radius.

[0559] [Formula 2]

[0560]

[0561] W L : Penetration weight

[0562] t: time

[0563] S: Cross-sectional area of ​​the pool (powder layer filling part)

[0564] ε: Porosity

[0565] ρ L : Liquid density

[0566] r: radius of the capillary formed by the particles in the powder layer

[0567] Y L : Surface tension of liquid

[0568] η L : Liquid viscosity

[0569] θ: contact angle between liquid and solid surface

[0570] The contact angle of the best wetting liquid (hexadecane in the case of inorganic solid electrolytes and ethylene glycol in the case of active materials) is assumed to be 0° and substituted into the measured W 2 / t, determines ε 2 r. Here, ε 2 r is a constant determined by the type of powder.

[0571] Substitute the W of each liquid into the formula of the other two solvents (ethylene glycol and bromonaphthalene in the case of inorganic solid electrolytes, hexadecane and bromonaphthalene in the case of active materials) 2 / t and ε 2 r, and cosθ was derived for each liquid.

[0572] The following Fowkes equation related to the contact angle components is solved for the dispersion component Y=γSV d , polar component X = γSV h The two-variable simultaneous equations were solved to obtain the dispersed component and polar component.

[0573] The above measurements were performed four times and the average values ​​were taken to obtain the dispersion component Xse (dispersed component) and polar component Yse (polar component) of the surface energy of the inorganic solid electrolyte, and the dispersion component Xam (dispersed component) and polar component Yam (polar component) of the surface energy of the active material. The units for all values ​​are mN / m.

[0574] [Formula 3]

[0575]

[0576] In addition, γLV h and γLV d is a known constant obtained from the surface tension γL of each liquid. For example, in the case of hexadecane, γLV d =44.4mN / m,γLV h =0.2mN / m.

[0577] <Measurement Method of Surface Energy (Surface Energy of Adhesive)>

[0578] (1) Preparation of polymer films

[0579] 100 μL of a 10% by mass binder (polymer) solution was applied to a silicon wafer (3×N type, manufactured by AS ONE Corporation) using a spin coater under the following conditions and then vacuum-dried at 100° C. for 2 hours to prepare an adhesive film (polymer film).

[0580] In addition, a 10% by mass solution of the binder was prepared using a combination of the binder and the dispersion medium used to prepare the inorganic solid electrolyte-containing compositions described in Tables 1-1 to 1-4 below.

[0581] -Measurement conditions-

[0582] Spin coater speed: 2000rpm

[0583] Spin coater spin time: 5 seconds

[0584] (2) Determination of contact angle θ

[0585] The contact angle θ of each liquid relative to the polymer film formed on the silicon wafer described above was measured using the θ / 2 method of the droplet method. Here, the angle formed between the sample surface (polymer film surface) and the droplet (the angle within the droplet) was measured as the contact angle θ after the droplet was placed in contact with the polymer film surface for 200 milliseconds.

[0586] (3) Derivation of the dispersion and polar components of surface energy

[0587] In the same manner as the derivation of the surface energy of the inorganic solid electrolyte and active material, the above-mentioned Fowkes formula is solved for the two-variable simultaneous equations of the dispersed component Y=γSVd and the polar component X=γSVh to obtain the dispersed component and the polar component.

[0588] The contact angle θ is measured four times and the average value is taken to obtain the dispersion component Xba (dispersive component) and polar component Yba (polar component) of the surface energy of the adhesive. The unit of both is mN / m.

[0589] [Measurement of Adsorption Rate of Binder to Inorganic Solid Electrolyte]

[0590] The adsorption rate was measured using the inorganic solid electrolyte, binder (polymer), and dispersion medium used to prepare each inorganic solid electrolyte-containing composition shown in Table 1.

[0591] That is, a binder solution with a concentration of 1% by mass was prepared by dissolving the binder prepared above in a dispersion medium. The binder solution and the inorganic solid electrolyte were placed in a 15 mL vial at a mass ratio of 42:1, stirred at 80 rpm for 1 hour at room temperature (25°C) by a mixing rotor, and then allowed to stand. The supernatant obtained by solid-liquid separation was filtered with a filter having a pore size of 1 μm, and the filtrate obtained was completely dried, and the mass of the binder remaining in the filtrate (the mass of the binder not adsorbed on the inorganic solid electrolyte) W was measured. A . By this mass W A and the mass W of the binder contained in the binder solution used for measurement B The adsorption rate of the binder to the inorganic solid electrolyte is calculated by the following formula.

[0592] The adsorption rate of the binder was set as the average value of the adsorption rates obtained by performing the above measurement twice.

[0593] Adsorption rate (%) = [(W B -W A ) / W B ]×100

[0594] In addition, the adsorption rate was measured using the inorganic solid electrolyte and binder taken out from the formed solid electrolyte layer and the dispersion medium used to prepare the inorganic solid electrolyte composition, and the same value was obtained.

[0595]

[0596]

[0597]

[0598]

[0599] <Abbreviations of the table>

[0600] LPS: LPS synthesized in Synthesis Example A

[0601] LLZ:Li7La3Zr2O 12

[0602] NMC:LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2

[0603] Si: Silicon

[0604] Gr: Graphite

[0605] The unit of "SP value" in the table is MPa 1 / 2 “Adsorption rate” refers to the adsorption rate of the binder to the inorganic solid electrolyte, and the unit is %. The unit of the dispersion component and polar component of the surface energy of the inorganic solid electrolyte, binder and active material is mN / m.

[0606] R SE represents {(Xse-Xba) 2 +(Yse-Yba) 2} 0.5 , unit is mN / m.

[0607] R AM Indicates {(Xse-Xam) 2 +(Yse-Yam) 2} 0.5 , unit is mN / m.

[0608] In compositions S-17 and S-21 to S-24 containing two types of binders, the surface energy, adsorption rate to the inorganic solid electrolyte, molecular weight, SP value and R SE , use " / " to describe the value of each adhesive.

[0609] The SP values ​​of the dispersion media were 18.9 for butyl acetate (n-butyl butyrate), 18.5 for toluene, 18.7 for xylene (a xylene isomer mixture with a molar ratio of ortho-isomer:para-isomer:meta-isomer = 1:5:2), and 16.9 for octane (n-octane).

[0610] <Fabrication of solid electrolyte sheets for all-solid-state secondary batteries>

[0611] The inorganic solid electrolyte compositions S-1 to S-34 obtained above were prepared and, one hour later, applied to a 20 μm thick aluminum foil using a baking applicator (trade name: SA-201, manufactured by TESTER SANGYO CO., LTD.). The inorganic solid electrolyte compositions were then heated at 110°C for two hours to dry (remove the dispersion medium). The dried inorganic solid electrolyte compositions were then pressed for 10 seconds at 25°C and 10 MPa using a hot press to produce solid electrolyte sheets S-1 to S-34 for all-solid-state secondary batteries. The solid electrolyte layer had a thickness of 50 μm.

[0612] <Manufacturing of positive electrode sheets for all-solid-state secondary batteries>

[0613] Each of the positive electrode compositions P-1 to P-20 obtained above was prepared. One hour later, the composition was applied onto a 20 μm thick aluminum foil using a baking applicator (trade name: SA-201). The composition was then heated at 110°C for one hour to dry the positive electrode composition (removing the dispersion medium). The dried positive electrode composition was then pressed at 25°C (10 MPa for 1 minute) using a hot press to produce positive electrode sheets P-1 to P-20 for all-solid-state secondary batteries each having a 100 μm thick positive electrode active material layer.

[0614] <Production of negative electrode sheets for all-solid-state secondary batteries>

[0615] Each of the negative electrode compositions N-1 to N-22 obtained above was prepared. One hour later, the composition was applied onto a 20 μm thick copper foil using a baking applicator (trade name: SA-201) and heated at 110°C for 1 hour. The negative electrode composition was then dried (the dispersion medium was removed) by heating it at 110°C for 2 hours using a vacuum dryer AVO-200NS (trade name, manufactured by AS ONE Corporation). The dried negative electrode composition was then pressed at 25°C (10 MPa, 1 minute) using a hot press to produce negative electrode sheets N-1 to N-22 for all-solid-state secondary batteries each having a 70 μm thick negative electrode active material layer.

[0616] The following evaluations were performed on each of the produced compositions and sheets, and the results are shown in Table 2.

[0617] <Evaluation 1: Dispersion Characteristics (Dispersibility)>

[0618] In the following dispersibility test, samples were taken from the composition applied to a substrate in each of the above-mentioned sheet production methods.

[0619] Each sampled composition (slurry) was suspended in the trough of a particle size analyzer (grinding tester) Model 232 / III (trade name, manufactured by AS ONE Corporation). The value read using the position of the line formed after scraping with a scraper as the scale mark was defined as the aggregate size X. Separately, the aggregate size X0 of a composition adjusted to a viscosity of 300 cP was measured in the same manner as described above for the aggregate size X. The aggregate size X and X0 obtained were used to calculate the aggregate size ratio [X / X0].

[0620] A composition with a viscosity of 300 cP was prepared by adjusting the amount of butyl butyrate as a solvent while maintaining the solid content ratio of each sampled composition (slurry). As described above, the viscosity is a value measured using an E-type viscometer.

[0621] This aggregate size ratio [X / X0] is included in any of the following evaluation criteria, and the ease of aggregation of solid particles is evaluated as the dispersibility of the composition.

[0622] In this test, the smaller the agglomerate size ratio [X / X0], the less likely the solid particles are to aggregate or precipitate, indicating excellent dispersibility. Evaluation criteria of "F" or higher indicate a passing level.

[0623] -Evaluation Criteria-

[0624] A: X / X0<1.1

[0625] B: 1.1≤X / X0<1.2

[0626] C: 1.2≤X / X0<1.3

[0627] D: 1.3≤X / X0<1.4

[0628] E: 1.4≤X / X0<1.5

[0629] F: 1.5≤X / X0<1.6

[0630] G: 1.6≤X / X0

[0631] <Evaluation 2: Dispersion Characteristics (Stability)>

[0632] In the dispersion stability test described below, samples were taken from the composition applied on the substrate in each of the sheet production methods described above.

[0633] Each sampled composition (slurry) was put into a glass test tube with a diameter of 10 mm and a height of 4 cm until the height was 4 cm, and allowed to stand at 25°C for 24 hours. The solid content reduction rate of the upper 30% (height) of the composition before and after standing was calculated by the following formula. According to any one of the following evaluation criteria, the ease of precipitation of solid particles caused by the passage of time was evaluated as the dispersion stability (storage stability) of the composition. In this test, the smaller the solid content reduction rate, the better the dispersion stability, and the evaluation standard "F" or above is a qualified level.

[0634] Solid content reduction rate (%) = [(solid content concentration of the upper 30% before standing - solid content concentration of the upper 30% after standing) / solid content concentration of the upper 30% before standing] × 100

[0635] -Evaluation Criteria-

[0636] A: Solid content reduction rate <1%

[0637] B: 1%≤Solid content reduction rate<3%

[0638] C: 3%≤Solid content reduction rate<5%

[0639] D: 5%≤Solid content reduction rate<7%

[0640] E: 7% ≤ solid content reduction rate < 9%

[0641] F: 9%≤Solid content reduction rate<11%

[0642] G: 11% ≤ solid content reduction rate

[0643] <Evaluation 3: Coating Suitability (Surface Properties)>

[0644] As the coating suitability of each composition, the maximum height roughness Rz of the solid electrolyte layer surface or the active material layer surface of each obtained sheet was measured and evaluated.

[0645] Specifically, the maximum height roughness Rz of the solid electrolyte layer surface or the active material layer surface of each sheet was measured in accordance with Japanese Industrial Standard (JIS) B 0601:2013 using the following measuring device and conditions.

[0646] The maximum height roughness Rz is included in any of the following evaluation criteria, and the ease of forming a constituent layer with a flat surface and good surface properties (surface properties) is evaluated as the coating suitability of the composition. In this test, the smaller the maximum height roughness Rz, the better the coating suitability (surface properties), and an evaluation criterion of "F" or higher is considered a passing level.

[0647] -Measurement equipment and conditions-

[0648] Measuring device: Three-dimensional micro-profile measuring instrument (Model ET-4000A, manufactured by Kosaka Laboratory Ltd.)

[0649] Analysis equipment: Three-dimensional surface roughness analysis system (model TDA-31)

[0650] Stylus: Tip radius 0.5μm, diamond

[0651] Needle pressure: 1μN

[0652] Measuring length: 5.0mm

[0653] Measuring speed: 0.02mm / s

[0654] Measurement interval: 0.62 μm

[0655] Cutoff value: None

[0656] Filtering method: Gaussian space type

[0657] Leveling: Yes (quadratic curve)

[0658] -Evaluation Criteria-

[0659] A: Rz<1.0μm

[0660] B: 1.0μm≤Rz<2.0μm

[0661] C: 2.0μm≤Rz<4.0μm

[0662] D: 4.0μm≤Rz<6.0μm

[0663] E: 6.0μm≤Rz<8.0μm

[0664] F: 8.0μm≤Rz<10μm

[0665] G: 10μm≤Rz

[0666] <Evaluation 4: Coating Suitability (Adhesion)>

[0667] As the coating suitability of each composition, the adhesion of the solid particles in the solid electrolyte layer or active material layer of each obtained sheet and the adhesion between the active material layer and the current collector were evaluated.

[0668] Each sheet produced was cut into a rectangle of 3 cm wide and 14 cm long. A cylindrical mandrel testing machine (product code 056, mandrel diameter 10 mm, manufactured by Allgood) was used to fix one end of the length direction of the cut sheet test piece in the above-mentioned testing machine. The central part of the sheet test piece was arranged to abut against the cylindrical mandrel, while the other part of the length direction of the sheet test piece was stretched with a force of 5 N in the length direction, while being bent 180° along the circumference of the mandrel (with the mandrel as the axis). In addition, in the sheet test piece, its solid electrolyte layer or active material layer is arranged on the side opposite to the mandrel (the substrate or collector is arranged on the mandrel side), and the width direction is set to be parallel to the axis of the mandrel. The test was carried out by gradually reducing the diameter of the mandrel from 32 mm.

[0669] The evaluation is carried out under the following conditions: in the state of being wound on the mandrel and in the state of being unwound and restored to a sheet form, the generation of defects (cracks, fissures, notches, etc.) caused by the collapse of the bonding of solid particles is measured on the solid electrolyte layer or active material layer. For the active material layer, the minimum diameter at which the peeling of the active material layer and the collector cannot be confirmed is further measured. This minimum diameter corresponds to any one of the following evaluation criteria.

[0670] In this test, the smaller the minimum diameter, the stronger the binding force of the solid particles constituting the solid electrolyte layer or active material layer, and the stronger the adhesion between the active material layer and the current collector. Evaluation criteria "F" or above are considered acceptable.

[0671] -Evaluation Criteria-

[0672] A: Minimum diameter <5mm

[0673] B: 5mm≤minimum diameter<6mm

[0674] C: 6mm≤minimum diameter<8mm

[0675] D: 8mm≤minimum diameter<10mm

[0676] E: 10mm≤minimum diameter<14mm

[0677] F: 14mm≤minimum diameter<25mm

[0678] G: 25mm≤minimum diameter

[0679] <Evaluation 5: Upper limit concentration of slurry>

[0680] In the preparation of each of the above compositions (slurries), a composition having a solid content concentration of 76% by mass was prepared by adjusting the amount of butyl butyrate. The composition having a solid content concentration of 76% by mass was placed in a container (a cylindrical container with a diameter of 5.0 cm and a height of 7.0 cm) placed on a table. The container was tilted 60 degrees from this state to confirm whether it had fluidity to the extent of sagging due to its own weight. In the case where the composition did not sag due to its own weight and did not have fluidity, butyl butyrate was added as a dispersion medium to reduce the solid content concentration of the composition by 1% by mass. After being dispersed at 2000 rpm for 1 minute in the above-mentioned rotation-revolution mixer, the composition was reconfirmed again as the composition having a solid content concentration of 76% by mass. This operation was repeated in a manner that the solid content concentration was reduced by 1% by mass. The maximum solid content concentration with fluidity was used as the slurry upper limit concentration, and the maximum concentration of the thick slurry that could be prepared was evaluated. If the solid content concentration is increased to a concentration exceeding the upper limit concentration for slurry formation, it will be difficult to use in the coating process. Therefore, the upper limit concentration for slurry formation becomes an indicator of the upper limit concentration of solid content of the composition that can be used in the coating process, and is preferably higher.

[0681] In the following tables, the unit of the upper limit concentration of slurry formation is mass %.

[0682] [Table 2-1]

[0683]

[0684] [Table 2-2]

[0685]

[0686] [Table 2-3]

[0687]

[0688] <Manufacturing of all-solid-state secondary batteries>

[0689] An all-solid-state secondary battery was manufactured using a positive electrode sheet for an all-solid-state secondary battery, a solid electrolyte sheet for an all-solid-state secondary battery, and a negative electrode sheet for an all-solid-state secondary battery in the combination of the constituent layers shown in Table 3.

[0690] The positive electrode sheets P-3, P-7, P-10, P-12, P-14, P-19, or P-20 for all-solid-state secondary batteries were punched into discs with a diameter of 10 mm and placed in a PET cylinder with an inner diameter of 10 mm. On the positive electrode active material layer side of the cylinder, the solid electrolyte sheets S-4, S-8, S-16, S-26, S-28, S-33, or S-34 for all-solid-state secondary batteries were punched into discs with a diameter of 10 mm and placed in the cylinder. 10 mm SUS rods were inserted from the openings at both ends of the cylinder. A pressure of 350 MPa was applied to the collector side of the positive electrode sheet for all-solid-state secondary batteries and the aluminum foil side of the solid electrolyte sheet for all-solid-state secondary batteries by the SUS rods and pressurized. The SUS rod on the side of the solid electrolyte sheet for all-solid-state secondary batteries was temporarily removed and the aluminum foil of the solid electrolyte sheet for all-solid-state secondary batteries was gently peeled off. Then, the negative electrode sheet N-2, N-8, N-9, N-15, N-19, N-21 or N-22 was punched into a disc shape with a diameter of 10 mm and inserted into the solid electrolyte layer of the solid electrolyte sheet for all-solid-state secondary batteries in the cylinder. The removed SUS rod was inserted into the cylinder again and fixed under a pressure of 50 MPa. In this way, all-solid-state secondary batteries No. C-1 to C-17 having a structure of aluminum foil (thickness 20 μm)-positive electrode active material layer (thickness 90 μm)-solid electrolyte layer (thickness 45 μm)-negative electrode active material layer (thickness 65 μm) were obtained.

[0691] Nos. C-1 to C-4, C-6 to C-8, and C-10 to C-17 are all-solid-state secondary batteries of the present invention, and Nos. C-5 and C-9 are all-solid-state secondary batteries for comparison.

[0692] <Evaluation 5: Cycle Characteristics>

[0693] The discharge capacity retention rate of each manufactured all-solid-state secondary battery was measured using a charge and discharge evaluation device TOSCAT-3000 (trade name, manufactured by TOYO SYSTEM Co., Ltd.).

[0694] Specifically, each all-solid-state secondary battery was charged at 25°C until the current density reached 0.1 mA / cm 2 The battery voltage reaches 3.6 V. Then, discharge until the current density reaches 0.1 mA / cm 2And the battery voltage reaches 2.5V. This charging and discharging once is regarded as an initialization charge and discharge cycle, and 3 initialization charge and discharge cycles are repeated under the same conditions to initialize it. Then, under the same conditions as the above-mentioned initialization charge and discharge cycle, the charge and discharge are repeated for 1000 cycles, and the discharge capacity of the 1st charge and discharge cycle and the discharge capacity of the 1000th cycle are measured by the charge and discharge evaluation device: TOSCAT-3000 (trade name). The discharge capacity maintenance rate is calculated by the following formula, and the discharge capacity maintenance rate is applied to the following evaluation criteria to evaluate the cycle characteristics of the all-solid-state secondary battery. In this test, the higher the evaluation criteria, the better the battery performance (cycle characteristics), and the initial battery performance can be maintained even if multiple charge and discharge are repeated (even if used for a long time).

[0695] In this test, an evaluation standard of "F" or higher is considered a passing level.

[0696] Furthermore, the initial discharge capacity of the all-solid-state secondary battery of the present invention showed a sufficient value to function as an all-solid-state secondary battery.

[0697] Discharge capacity retention rate (%) = (discharge capacity at the 1000th cycle / discharge capacity at the 1st cycle) × 100

[0698] -Evaluation Criteria-

[0699] A: 90% ≤ discharge capacity retention rate

[0700] B: 85%≤discharge capacity retention rate<90%

[0701] C: 80%≤discharge capacity retention rate<85%

[0702] D: 75%≤discharge capacity retention rate<80%

[0703] E: 70%≤discharge capacity retention rate<75%

[0704] F: 60%≤discharge capacity retention rate<70%

[0705] G: Discharge capacity retention rate <60%

[0706] [Table 3]

[0707] Battery No. Negative electrode active material layer Solid electrolyte layer Positive electrode active material layer Cycle characteristics C-1 N-8 S-8 P-7 A C-2 N-8 S-16 P-10 D C-3 N-9 S-8 P-10 E C-4 N-9 S-16 P-7 C C-5 N-9 S-16 P-10 G C-6 N-8 S-4 P-3 E C-7 N-2 S-8 P-3 E C-8 N-2 S-4 P-7 C C-9 N-2 S-4 P-3 G C-10 N-19 S-28 P-14 A C-11 N-19 S-26 P-12 E C-12 N-19 S-33 P-19 C C-13 N-21 S-33 P-19 E C-14 N-15 S-28 P-14 C C-15 N-15 S-26 P-19 E C-16 N-15 S-33 P-12 F C-17 N-22 S-34 P-20 C

[0708] The following can be seen from the results shown in Tables 2 and 3.

[0709] Comparative inorganic solid electrolyte compositions Nos. S-4, S-20, P-3, and N-2 did not contain a polymer binder with an adsorption rate that met the requirements of the present invention. These compositions exhibited poor dispersion properties and coating suitability. Furthermore, the comparative all-solid-state secondary battery No. C-9, which used these comparative inorganic solid electrolyte compositions to form each layer, did not exhibit adequate cycling performance.

[0710] Comparative inorganic solid electrolyte compositions No. S-16, S-18, P-10, N-6, and N-9 do not contain a polymer binder satisfying the relationship of formula (1) specified in the present invention. These compositions exhibited poor dispersion characteristics and coating suitability. Furthermore, the comparative all-solid-state secondary battery No. C-5, in which each layer was composed of these comparative inorganic solid electrolyte compositions, did not exhibit sufficient cycling characteristics.

[0711] In contrast, the inorganic solid electrolyte-containing compositions Nos. S-1 to S-3, S-5 to S-15, S-17, S-19, S-21 to S-34, P-1, P-2, P-4 to P-9, P-11 to P-20, N-1, N-3 to N-5, N-7, N-8, and N-10 to N-22 of the present invention contain a polymer binder having an adsorption rate of 50% or less as specified in the present invention and satisfying the relationship defined by formula (1) with respect to surface energy with the inorganic solid electrolyte. These compositions exhibit both high levels of dispersion characteristics (dispersibility and stability) and coating suitability (surface properties and adhesion). By using these inorganic solid electrolyte-containing compositions to form any of the constituent layers of an all-solid-state secondary battery, as shown in Nos. C-1 to C-4, C-6 to C-8, and C-10 to C-17, it was found that an all-solid-state secondary battery exhibiting excellent cycle characteristics can be produced.

[0712] Explanation of symbols

[0713] 1-Negative electrode collector, 2-Negative electrode active material layer, 3-Solid electrolyte layer, 4-Positive electrode active material layer, 5-Positive electrode collector, 6-Working part, 10-All-solid-state secondary battery.

Claims

1. An inorganic solid electrolyte composition comprising: an inorganic solid electrolyte having ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, a polymer binder, and a dispersion medium; The polymer binder is a dissolving polymer binder that dissolves in the dispersion medium. The inorganic solid electrolyte-containing composition may further contain a particulate binder, And the composition is used for all-solid-state secondary batteries, in, The adsorption rate of the polymer binder in the dispersion medium to the inorganic solid electrolyte is 50% or less, The inorganic solid electrolyte and the polymer binder satisfy the relationship defined by the following formula (1) with respect to surface energy: (Xse - Xba) 2 +(Yse - Yba) 2 ≤R 2 Equation (1) Wherein, Xse represents the dispersion component of the surface energy of the inorganic solid electrolyte, Yse represents the polar component of the surface energy of the inorganic solid electrolyte, Xba represents the dispersion component of the surface energy of the polymer binder, Yba represents the polar component of the surface energy of the polymer binder, R is 20.

2. The inorganic solid electrolyte composition according to claim 1, wherein The adsorption rate is 5% or more and less than 30%.

3. The inorganic solid electrolyte-containing composition according to claim 1 or 2, further comprising an active material, wherein the active material and the polymer binder satisfy the relationship defined by the following formula (2) with respect to surface energy: (Xam - Xba) 2 +(Yam - Yba) 2 ≤r 2 Equation (2) In the formula, Xam represents the dispersion component of the surface energy of the active substance, Yam represents the polar component of the surface energy of the active substance, Xba represents the dispersion component of the surface energy of the polymer binder, Yba represents the polar component of the surface energy of the polymer binder, and r is 30.

4. The inorganic solid electrolyte composition according to claim 3, wherein The inorganic solid electrolyte, the polymer binder, and the active material satisfy the relationship defined by the following formula (3) with respect to surface energy: R SE +R AM ≤30 formula (3) Where R SE 2 Represents the left side of the formula (1), R AM 2 It represents the left side of the above formula (2).

5. The inorganic solid electrolyte-containing composition according to claim 1 or 2, wherein The dispersion medium comprises at least one selected from ester compounds, ketone compounds, ether compounds, alcohol compounds, amide compounds, amine compounds and nitrile compounds, and the molecular weight of the polymer binder is 10,000 to 700,000. or, The dispersion medium comprises at least one selected from aromatic compounds and aliphatic compounds, and the molecular weight of the polymer binder is 70,000 to 1,000,000.

6. The inorganic solid electrolyte composition according to claim 1 or 2, wherein The difference between the SP value of the dispersion medium and the SP value of the polymer binder is 3 or less.

7. The inorganic solid electrolyte-containing composition according to claim 1 or 2, wherein The polymer forming the polymer binder comprises a constituent having a functional group selected from the following functional group group (a), <Functional group (a)> Hydroxyl group, amino group, carboxyl group, sulfo group, phosphoric acid group, phosphonic acid group, sulfanyl group, ether bond, imino group, ester bond, amide bond, carbamate bond, urea bond, heterocyclic group, aromatic group, carboxylic anhydride group, fluoroalkyl group. 8 . A sheet for an all-solid-state secondary battery, comprising a layer comprising the inorganic solid electrolyte composition according to claim 1 .

9. An all-solid-state secondary battery comprising, in order, a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer, wherein: At least one of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer includes a layer formed from the inorganic solid electrolyte composition according to any one of claims 1 to 7 . 10 . A method for producing a sheet for an all-solid-state secondary battery, comprising the step of forming a film containing the inorganic solid electrolyte composition according to claim 1 . 11 . A method for producing an all-solid-state secondary battery, comprising the step of assembling the all-solid-state secondary battery sheet obtained by the production method according to claim 10 into the all-solid-state secondary battery.

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