Composition Containing Inorganic Solid Electrolyte, All-Solid-State Secondary Battery, Related Sheet, and Manufacturing Method

Abstract

The present invention provides a composition containing an inorganic solid electrolyte, a sheet for all-solid-state secondary battery and an all-solid-state secondary battery using the composition containing the inorganic solid electrolyte, and a manufacturing method of the sheet for all-solid-state secondary battery and the all-solid-state secondary battery. The composition containing the inorganic solid electrolyte contains an inorganic solid electrolyte, a polymer binder and a dispersion medium. Among them, the polymer binder contains a vinylidene fluoride constituent and a hexafluoropropylene constituent of 21 to 65 mol%, and contains a polymer binder composed of a fluorine-based copolymer having a tensile fracture strain of 500% or more. The adsorption rate of the polymer binder with respect to the inorganic solid electrolyte is less than 60%.

Description

Technical Field

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

[0002] In an all-solid-state secondary battery, all of the negative electrode, electrolyte, and positive electrode are composed of solids, and it is possible to significantly improve the safety or reliability, which is an issue, of a battery using an organic electrolyte. In addition, the lifespan can also be extended. Furthermore, the all-solid-state secondary battery can be configured in a structure in which the electrodes and the electrolyte are directly arranged and connected in series. Therefore, compared with a secondary battery using an organic electrolyte, it can achieve a higher energy density and is expected to be applied to electric vehicles or large-scale storage batteries, etc.

[0003] In such an all-solid-state secondary battery, as materials for forming constituent layers (such as a solid electrolyte layer, a negative electrode active material layer, a positive electrode active material layer, etc.), an inorganic solid electrolyte, an active material, etc. can be cited. This inorganic solid electrolyte, particularly oxide-based inorganic solid electrolytes and sulfide-based inorganic solid electrolytes, have been expected in recent years as electrolyte materials having a high ionic conductivity close to that of an organic electrolyte.

[0004] As a material for forming a constituent layer of an all-solid-state secondary battery (constituent layer forming material), a material containing the above inorganic solid electrolyte, etc. has been proposed. For example, Patent Document 1 describes a slurry for a negative electrode of a sulfide-based solid battery, which contains at least a fluorine-based copolymer containing a vinylidene fluoride monomer unit, a negative electrode active material, and a solvent or a dispersion medium, and is characterized in that when the dry volume is set to 100% by volume, the content ratio of the fluorine-based copolymer is 1.4 to 2.2% by volume.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Laid-Open No. 2014-078400 Summary of the Invention

[0008] Technical Problem to be Solved by the Invention

[0009] When the constituent layer of an all-solid-state secondary battery is formed by solid particle materials (inorganic solid electrolytes, active materials, conductive aids, etc.), in the constituent layer forming material, from the viewpoint of improving the battery performance (such as cycle characteristics) of the all-solid-state secondary battery with the constituent layer thus formed, it is required to stably maintain the excellent dispersibility characteristics (dispersion stability) of the solid particle material (also referred to as solid particles) just after preparation, and maintain the high dispersion characteristics of fluidity and the characteristics (handling properties) of good surface properties with appropriate viscosity. Dispersion stability and handling properties are considered to be one of the important factors of the correlation of inorganic solid electrolytes, etc. with adhesives. However, the solid electrolyte composition described in patent document 1 does not describe this viewpoint.

[0010] However, in recent years, the research and development of high performance and practical application of electric vehicles has progressed rapidly, and the requirements for battery performance (e.g., cycle characteristics) required for all-solid-state secondary batteries have become increasingly high. In order to meet such requirements in recent years, it is necessary to develop a constituent layer forming material that has both dispersion stability and handling properties (fluidity, surface properties of the coating surface) at a higher level.

[0011] The present invention aims to provide a composition containing an inorganic solid electrolyte with excellent dispersion stability and handling properties. In addition, the present invention aims to provide a sheet material for an all-solid-state secondary battery and an all-solid-state secondary battery using the composition containing an inorganic solid electrolyte, and a method for manufacturing the sheet material for an all-solid-state secondary battery and the all-solid-state secondary battery.

[0012] Means for solving technical problems

[0013] The inventors of the present invention have repeatedly conducted various studies and found that in a composition containing an inorganic solid electrolyte, an inorganic solid electrolyte and a polymer binder formed by a specific fluorine-based copolymer and a specific polymer binder having an adsorption rate of less than 60% relative to the inorganic solid electrolyte are used in combination, thereby suppressing the re-agglomeration or precipitation caused by the inorganic solid electrolyte over time, and suppressing the excessive increase in viscosity (thickening). In addition, by using the composition containing the inorganic solid electrolyte as a constituent layer forming material, it is found that a sheet for all-solid-state secondary batteries with a flat coating surface and good surface properties and a low-resistance constituent layer, as well as an all-solid-state secondary battery with excellent cycle characteristics, can be achieved. The present invention has been further repeatedly studied based on these insights, thereby completing the present invention.

[0014] That is, the above-mentioned problems are solved by the following means.

[0015] <1> A composition containing an inorganic solid electrolyte, 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, wherein:

[0016] The polymer binder contains: a polymer binder composed of a fluorine-based copolymer containing a vinylidene fluoride constituent and a hexafluoropropylene constituent of 21 to 65 mol% and having a tensile fracture strain of 500% or more.

[0017] The adsorption rate of the polymer binder composed of the fluorine-based copolymer in the above dispersion medium with respect to the inorganic solid electrolyte is less than 60%.

[0018] <2> The composition containing an inorganic solid electrolyte according to <1>, wherein

[0019] The polymer binder composed of the fluorine-based copolymer is dissolved in the dispersion medium.

[0020] <3> The composition containing an inorganic solid electrolyte according to <1> or <2>, wherein

[0021] The content of the hexafluoropropylene constituent in the fluorine-based copolymer is 30 to 50 mol%.

[0022] <4> The composition containing an inorganic solid electrolyte according to any one of <1> to <3>, wherein

[0023] The tensile fracture strain is 700% or more.

[0024] <5> The composition containing an inorganic solid electrolyte according to any one of <1> to <4>, wherein

[0025] The peel strength of the polymer binder composed of the fluorine-based copolymer with respect to the aluminum foil is 0.1 N / mm or more.

[0026] <6> The composition containing an inorganic solid electrolyte according to any one of <1> to <5>, wherein

[0027] The weight-average molecular weight of the copolymer is 50,000 to 1,500,000.

[0028] <7> The composition containing an inorganic solid electrolyte according to any one of <1> to <6>, wherein

[0029] The fluorine-based copolymer contains a constituent having a functional group selected from the following functional group group (a).

[0030] <Functional group group (a)>

[0031] Hydroxyl group, amino group, carboxyl group, sulfo group, phosphoric acid group, phosphonic acid group, thioalkyl group, ether bond, imino group, ester bond, amide bond, urethane bond, urea bond, heterocyclic group, aryl group, carboxylic anhydride group, isocyanate group, alkoxysilyl group, fluoroalkyl group, siloxanyl group

[0032] <8> The composition containing an inorganic solid electrolyte according to <7>, wherein

[0033] The content of the component having a functional group selected from the above functional group group (a) in the fluorine-based copolymer is 0.01 to 10 mol%.

[0034] <9> The composition containing an inorganic solid electrolyte according to any one of <1> to <8>, wherein

[0035] The polymer binder contains a granular binder having an average particle diameter of 1 to 1000 nm.

[0036] <10> The composition containing an inorganic solid electrolyte according to any one of <1> to <9>, wherein

[0037] The polymer binder contains a binder composed of a hydrocarbon-based polymer, a binder composed of a (meth)acrylic acid-based polymer, or a polymer binder composed of an ethylene-based polymer.

[0038] <11> The composition containing an inorganic solid electrolyte according to any one of <1> to <10>, which contains an active material.

[0039] <12> The composition containing an inorganic solid electrolyte according to <11>, wherein

[0040] The adsorption rate of the polymer binder composed of a fluorine-based copolymer with respect to the active material is 90% or less.

[0041] <13> The composition containing an inorganic solid electrolyte according to any one of <1> to <12>, which contains a conductive aid.

[0042] <14> The composition containing an inorganic solid electrolyte according to any one of <1> to <13>, wherein

[0043] The inorganic solid electrolyte is a sulfide-based inorganic solid electrolyte.

[0044] <15> A sheet for an all-solid-state secondary battery, which has a layer composed of the composition containing an inorganic solid electrolyte according to any one of <1> to <14> above.

[0045] <16> An all-solid-state secondary battery, which sequentially includes a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer, wherein

[0046] At least one of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer is a layer composed of the composition containing an inorganic solid electrolyte according to any one of <1> to <14>.

[0047] <17> A method for manufacturing a sheet for an all-solid-state secondary battery, which forms a film of the composition containing an inorganic solid electrolyte described in any one of <1> to <14> above.

[0048] <18> A method for manufacturing an all-solid-state secondary battery, which manufactures an all-solid-state secondary battery by the manufacturing method described in <17> above.

[0049] Advantages of the Invention

[0050] The present invention can provide a composition containing an inorganic solid electrolyte having excellent dispersion characteristics such as dispersion stability and processability (fluidity, surface property). Further, the present invention can provide a sheet for an all-solid-state secondary battery and an all-solid-state secondary battery having a layer composed of the composition containing an inorganic solid electrolyte. In addition, the present invention can provide a method for manufacturing a sheet for an all-solid-state secondary battery and an all-solid-state secondary battery using the composition containing an inorganic solid electrolyte.

[0051] Regarding the above features, other features, and advantages of the present invention, they should become clearer by appropriately referring to the drawings and according to the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] 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 OF THE INVENTION

[0053] In the present invention, the numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value.

[0054] In the present invention, the description of a compound (for example, when referring to a compound with a compound name at the end) means that it includes not only the compound itself but also its salts and its ions. Further, it means derivatives in which a part such as an introduced substituent is changed within a range not impairing the effects of the present invention.

[0055] In the present invention, (meth)acrylic acid means one or both of acrylic acid and methacrylic acid. The same applies to (meth)acrylate.

[0056] In the present invention, regarding substituents, linking groups, etc. (hereinafter referred to as substituents, etc.) for which substitution or non-substitution is not clearly described, it means that appropriate substituents may be present on the group. Therefore, in the present invention, even when simply described as a YYY group, the YYY group includes not only the form without substituents but also the form with substituents. The same applies to the meaning of a compound for which substitution or non-substitution is not clearly described. As preferred substituents, for example, the following substituent Z can be mentioned.

[0057] 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 each of the substituents etc. can be the same as or different from one another. And even without specific description, when multiple substituents etc. are adjacent, it means that these can be linked or fused to each other to form a ring.

[0058] In the present invention, the polymer refers to a polymer, but has the same meaning as the so-called high molecular compound.

[0059] [Composition containing an inorganic solid electrolyte]

[0060] The composition containing an inorganic solid electrolyte of the present invention contains 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 contained in the composition containing an inorganic solid electrolyte is a fluorine-based copolymer containing a vinylidene fluoride constituent and a hexafluoropropylene constituent, and contains one or two or more fluorine-based copolymers (sometimes simply referred to as copolymers) in which the content of the hexafluoropropylene constituent in the fluorine-based copolymer is 21 to 65 mol% and the tensile fracture strain is 500% or more.

[0061] The composition containing an inorganic solid electrolyte of the present invention only needs to contain, as the polymer binder, a polymer binder (sometimes called a fluorine-containing binder) composed of the above copolymer with respect to the inorganic solid electrolyte and the dispersion medium, and there is no particular limitation on its containing state etc. For example, in the composition containing an inorganic solid electrolyte, the polymer binder may or may not be adsorbed on the inorganic solid electrolyte, and when adsorbed, the degree thereof may be within the range of the adsorption rate described later.

[0062] The fluorine-containing binder functions as a binder that binds solid particles such as inorganic solid electrolytes (in addition, active substances and conductive aids that can coexist) to each other (for example, inorganic solid electrolytes to each other, inorganic solid electrolytes and active substances, active substances to each other) in at least a layer formed of the composition containing an inorganic solid electrolyte. In addition, it also functions as a binder that binds a current collector and solid particles. In the composition containing an inorganic solid electrolyte, the polymer binder may or may not have the function of binding solid particles to each other.

[0063] The composition containing an inorganic solid electrolyte of the present invention is preferably a slurry in which the inorganic solid electrolyte is dispersed in a dispersion medium. At this time, the fluorine-containing binder preferably has the function of dispersing solid particles in the dispersion medium. And when the fluorine-containing binder (in a solid state) is dispersed in the dispersion medium, within the range not impairing the effects of the present invention, a part of it may be dissolved in the dispersion medium.

[0064] The dispersion stability and processability (fluidity, surface properties) of the composition containing an inorganic solid electrolyte of the present invention are excellent. By using the composition containing an inorganic solid electrolyte as a constituent layer-forming material, a sheet for all-solid-state secondary batteries having a low-resistance constituent layer with a flat surface and excellent surface properties can be achieved, and an all-solid-state secondary battery having excellent cycle characteristics can be achieved.

[0065] In the method of forming an active material layer formed on a current collector from the composition containing an inorganic solid electrolyte of the present invention, strong adhesion between the current collector and the active material layer can also be achieved, and the cycle characteristics can be further improved.

[0066] The above effects are achieved by using a fluorine-containing adhesive having a specific adsorption rate formed from a fluorine-based copolymer containing the above constituent components in a specific ratio and showing a specific tensile fracture strain, in combination with a dispersion medium and an inorganic solid electrolyte, in the composition containing an inorganic solid electrolyte of the present invention. The detailed reason is not clear, but it is considered that the correlation between the inorganic solid electrolyte and the like in the composition containing an inorganic solid electrolyte and the adhesive can be improved.

[0067] That is, it is considered that a fluorine-containing adhesive formed from a fluorine-based copolymer containing a vinylidene fluoride constituent component and 21 to 65 mol% of a hexafluoropropylene constituent component and having a tensile fracture strain of 500% or more, and showing an adsorption rate of less than 60% with respect to the inorganic solid electrolyte, does not excessively adsorb to the inorganic solid electrolyte in the composition containing an inorganic solid electrolyte, and can suppress re-aggregation or precipitation of the inorganic solid electrolyte not only after the preparation of the composition containing an inorganic solid electrolyte but also over time. In addition, the fluorine-based copolymer easily maintains the interaction of the inorganic solid electrolytes in the composition, and can cause the repulsive force between the fluorine atoms in the copolymer to act. As a result, a high degree of dispersion (excellent dispersion stability) immediately after preparation can be stably maintained, and an excessive increase in viscosity can also be suppressed, and good fluidity (excellent processability) can be expressed.

[0068] When a constituent layer is formed using the composition containing an inorganic solid electrolyte of the present invention that exhibits such excellent dispersion characteristics, re-aggregates or precipitates of the inorganic solid electrolyte can be suppressed even during the film formation of the constituent layer (for example, when coating the composition containing the inorganic solid electrolyte and during drying). Thereby, deviation in the contact state between the inorganic solid electrolytes in the constituent layer can be suppressed. In particular, when the composition containing the inorganic solid electrolyte contains an active material or the like, it is considered that specific particles such as the active material are less likely to be unevenly distributed in the constituent layer (the solid particles are uniformly arranged in the constituent layer). As a result, an increase in the interfacial resistance between the solid particles and the resistance of the constituent layer can be suppressed. In addition, when the composition containing the inorganic solid electrolyte is formed into a film, especially during coating, the composition containing the inorganic solid electrolyte flows (levels) appropriately, and there are no surface roughnesses such as unevenness due to insufficient flow or excessive flow (the surface property of the coating surface is excellent), resulting in a constituent layer with good surface properties. Thus, it is considered that a sheet for an all-solid-state secondary battery having a constituent layer with a flat surface and low resistance can be realized.

[0069] Moreover, an all-solid-state secondary battery having a constituent layer with suppressed resistance increase and a flat surface is less likely to generate overcurrent during charge and discharge, can prevent deterioration of solid particles, and the interfacial contact state with other layers adjacent to the surface of the constituent layer becomes good (high adhesion). Therefore, it is considered that even when repeatedly charged and discharged, the battery characteristics will not be significantly reduced, and an all-solid-state secondary battery with excellent cycle characteristics can be realized.

[0070] When an active material layer is formed from the composition containing an inorganic solid electrolyte of the present invention, as described above, the constituent layer is formed while maintaining the highly (uniform) dispersed state just after preparation. Therefore, it is considered that the contact (adhesion) between the fluorine-containing binder and the surface of the current collector is not hindered by solid particles such as preferential precipitation, and the fluorine-containing binder can contact (adhere) to the surface of the current collector in a state dispersed with the solid particles. In addition, the fluorine-based copolymer precipitated during the formation of the active material can elongate without being cut in the active material layer and can maintain its molecular structure. Thereby, an electrode sheet for an all-solid-state secondary battery in which an active material layer is formed from the composition containing an inorganic solid electrolyte of the present invention on a current collector can achieve strong adhesion between the current collector and the active material. And an all-solid-state secondary battery in which an active material layer is formed from the composition containing an inorganic solid electrolyte of the present invention on a current collector shows strong adhesion between the current collector and the active material and can achieve further improvement in cycle characteristics.

[0071] The composition containing an inorganic solid electrolyte of the present invention can preferably be used as a sheet for all-solid-state secondary batteries (including electrode sheets for all-solid-state secondary batteries) or a forming material for a solid electrolyte layer or an active material layer of an all-solid-state secondary battery (a layer-forming constituent material). In particular, it can preferably be used as a forming material for a negative electrode sheet or a negative electrode active material layer of an all-solid-state secondary battery containing a negative electrode active material with large expansion and contraction caused by charge and discharge, and high cycle characteristics can also be achieved in this manner.

[0072] The composition containing an inorganic solid electrolyte of the present invention is preferably a non-aqueous composition. In the present invention, the non-aqueous composition includes not only a form that does not contain moisture but also a form in which the water content (also referred to as the moisture 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 composition containing an inorganic solid electrolyte is a non-aqueous composition, deterioration of the inorganic solid electrolyte can be suppressed. The water content represents the amount of water contained in the composition containing an inorganic solid electrolyte (the mass ratio to the composition containing an inorganic solid electrolyte), and specifically, it is a value obtained by filtering with a 0.02 μm membrane filter and measuring by Karl Fischer titration.

[0073] The composition containing an inorganic solid electrolyte of the present invention also includes the following form: in addition to containing an inorganic solid electrolyte, it also contains an active material, a conductive additive, etc. (the composition of this form is referred to as an electrode composition).

[0074] Hereinafter, the components contained in the composition containing an inorganic solid electrolyte of the present invention and the components that can be contained will be described.

[0075] <Inorganic solid electrolyte>

[0076] The composition containing an inorganic solid electrolyte of the present invention contains an inorganic solid electrolyte.

[0077] 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 therein. Considering that it does not contain an organic substance as a main ion-conductive material, it is clearly distinguished from an organic solid electrolyte (a polymer electrolyte represented by polyethylene oxide (PEO) or the like, and an organic electrolyte salt represented by lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) or the like). Also, since the inorganic solid electrolyte is solid in a stable state, it usually does not dissociate or ionize into cations and anions. In this regard, it is clearly distinguished from inorganic electrolyte salts (LiPF6, LiBF4, lithium bis(fluorosulfonyl)imide (LiFSI), LiCl, etc.) that dissociate or ionize into cations and anions in an electrolyte solution or a polymer. As long as the inorganic solid electrolyte has ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, there is no particular limitation, and it usually does not have electronic conductivity. When the all-solid-state secondary battery of the present invention is a lithium-ion battery, it is preferable that the inorganic solid electrolyte has ion conductivity of lithium ions.

[0078] The above inorganic solid electrolyte can be appropriately selected from solid electrolyte materials commonly used for all-solid-state secondary batteries for use. For example, as the inorganic solid electrolyte, (i) a sulfide-based inorganic solid electrolyte, (ii) an oxide-based inorganic solid electrolyte, (iii) a halide-based inorganic solid electrolyte, and (iv) a hydride-based inorganic solid electrolyte can be cited. From the viewpoint of being able to form a better interface between the active material and the inorganic solid electrolyte, a sulfide-based inorganic solid electrolyte is preferred.

[0079] (i) Sulfide-based inorganic solid electrolyte

[0080] The sulfide-based inorganic solid electrolyte is preferably a compound that contains a sulfur atom, has ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and has electronic insulation. The sulfide-based inorganic solid electrolyte preferably contains at least Li, S, and P as elements and has lithium ion conductivity, but may also contain other elements in addition to Li, S, and P depending on the purpose or situation.

[0081] As the sulfide-based inorganic solid electrolyte, for example, a lithium ion-conductive inorganic solid electrolyte that satisfies the composition represented by the following formula (S1) can be cited.

[0082] L a1 M b1 P c1 S d1 A e1 (S1)

[0083] 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 ratios of the respective elements, and a1:b1:c1:d1:e1 satisfies 1 to 12:0 to 5:1:2 to 12:0 to 10. a1 is preferably 1 to 9, more preferably 1.5 to 7.5. b1 is preferably 0 to 3, more preferably 0 to 1. d1 is preferably 2.5 to 10, more preferably 3.0 to 8.5. e1 is preferably 0 to 5, more preferably 0 to 3.

[0084] As described below, the composition ratios of the respective elements can be controlled by adjusting the blending amounts of the raw material compounds when manufacturing the sulfide-based inorganic solid electrolyte.

[0085] The sulfide-based inorganic solid electrolyte can be non-crystalline (glass), can be crystallized (glass-ceramized), or can be partially crystallized. For example, a Li-P-S-based glass containing Li, P, and S or a Li-P-S-based glass ceramic containing Li, P, and S can be used.

[0086] The sulfide-based inorganic solid electrolyte can be manufactured by reacting at least two or more raw materials such as lithium sulfide (Li2S), phosphorus sulfide (e.g., diphosphorus pentasulfide (P2S5)), elemental phosphorus, elemental sulfur, sodium sulfide, hydrogen sulfide, lithium halide (e.g., LiI, LiBr, LiCl), and sulfides of the elements represented by the above M (e.g., SiS2, SnS, GeS2).

[0087] In the Li-P-S-based glass and the Li-P-S-based glass ceramic, the ratio of Li2S to P2S5 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 preferably be set to 1×10 -4 S / cm or more, more preferably set to 1×10 -3 S / cm or more. Although there is no particular upper limit set, it is actually 1×10 -1 S / cm or less.

[0088] As an example of a specific sulfide-based inorganic solid electrolyte, examples of the raw material combinations 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-Al2S3, 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. Among them, the mixing ratio of each raw material is not limited. As a method for synthesizing a sulfide-based inorganic solid electrolyte material using such a raw material composition, for example, an amorphization method can be cited. As the amorphization method, for example, a mechanical polishing method, a solution method, and a melt quenching method can be cited. Processing at room temperature can be performed, thereby simplifying the manufacturing process.

[0089] (ii) Oxide-based inorganic solid electrolyte

[0090] The oxide-based inorganic solid electrolyte is preferably a compound containing oxygen atoms, having ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and having electronic insulation.

[0091] Regarding the oxide-based inorganic solid electrolyte, as the ionic conductivity, it is preferably 1×10 -6 S / cm or more, more preferably 5×10 -6 S / cm or more, and particularly preferably 1×10 -5 S / cm or more. Although there is no particular upper limit set, it is actually 1×10 -1 S / cm or less.

[0092] As a specific compound example, for example, Li xa La yaTiO3〔where xa satisfies 0.3 ≤ xa ≤ 0.7 and ya satisfies 0.3 ≤ ya ≤ 0.7.〕(LLT); Li xb La yb Zr zb M bb mb O nb (M bb is one or more elements selected from Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In, and Sn. xb satisfies 5 ≤ xb ≤ 10, yb satisfies 1 ≤ yb ≤ 4, zb satisfies 1 ≤ zb ≤ 4, mb satisfies 0 ≤ mb ≤ 2, 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 (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. D 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, and 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 having a LISICON (Lithium super ionic conductor) type crystal structure 3.5 Zn 0.25 GeO4; La having a perovskite type crystal structure 0.55 Li 0.35 TiO3; LiTi2P3O having a NASICON (Natrium super ionic conductor) type 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 having a garnet type crystal structure 12 (LLZ), etc.

[0093] Moreover, it is also preferably a phosphorus compound containing Li, P, and O. For example, lithium phosphate (Li3PO4) can be cited; LiPON in which a part of the oxygen in lithium phosphate is replaced by nitrogen; LiPOD 1 (D 1 is preferably at least one element selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Ag, Ta, W, Pt, and Au.)., etc.

[0094] In addition, LiA 1 ON (A 1 is at least one element selected from Si, B, Ge, Al, C, and Ga.) can also be preferably used., etc.

[0095] (iii) Halide - based inorganic solid electrolyte

[0096] The halide - based inorganic solid electrolyte is preferably a compound containing a halogen atom, having conductivity of ions of a metal belonging to Group 1 or Group 2 of the periodic table, and having electron insulation.

[0097] As the halide - based inorganic solid electrolyte, there is no particular limitation. For example, compounds such as LiCl, LiBr, LiI, Li3YBr6, and Li3YCl6 described in ADVANCED MATERIALS, 2018, 30, 1803075 can be cited. Among them, Li3YBr6 and Li3YCl6 are preferred.

[0098] (iv) Hydride - based inorganic solid electrolyte

[0099] The hydride-based inorganic solid electrolyte is preferably a compound containing hydrogen atoms, having ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and having electron insulating properties.

[0100] There is no particular limitation on the hydride-based inorganic solid electrolyte, and examples thereof include LiBH4, Li4(BH4)3I, 3LiBH4-LiCl, etc.

[0101] The inorganic solid electrolyte is preferably in the form of particles. At this time, the particle size (volume average particle size) of the inorganic solid electrolyte is not particularly limited, and is preferably 0.01 μm or more, more preferably 0.1 μm or more. As the upper limit, it is preferably 100 μm or less, more preferably 50 μm or less.

[0102] The measurement of the particle size of the inorganic solid electrolyte is carried out by the following steps. In a 20 mL sample bottle, a 1 mass% dispersion is prepared by diluting the inorganic solid electrolyte particles with water (heptane in the case of substances unstable to water). The diluted dispersion sample is irradiated with ultrasonic waves at 1 kHz for 10 minutes, and then immediately used in the test. Using this dispersion sample, and using a laser diffraction / scattering particle size distribution measuring device LA-920 (trade name, manufactured by HORIBA, Ltd.) and performing 50 data acquisitions at a temperature of 25 °C using a measurement quartz cell, the volume average particle size is obtained. Other detailed conditions, etc. are referred to as needed in accordance with the description in Japanese Industrial Standard (JIS) Z8828:2013 "Particle Size Analysis - Dynamic Light Scattering Method". Five specimens are prepared for each level and the average value is adopted.

[0103] The inorganic solid electrolyte may contain one type or two or more types.

[0104] When forming the solid electrolyte layer, the mass (mg) of the inorganic solid electrolyte per unit area (cm 2 ) (unit area weight) of the solid electrolyte layer 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 .

[0105] Among them, when the composition containing the inorganic solid electrolyte contains the active material described later, regarding the unit area weight of the inorganic solid electrolyte, it is preferable that the total amount of the active material and the inorganic solid electrolyte is within the above range.

[0106] The content of the inorganic solid electrolyte in the composition containing the inorganic solid electrolyte is not particularly limited. From the viewpoint of adhesiveness and further from the viewpoint of dispersibility, in 100% by mass of the solid components, it is preferably 50% by mass or more, more preferably 70% by mass or more, and particularly preferably 90% by mass or more. As the 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.

[0107] However, when the composition containing the inorganic solid electrolyte contains the active material described later, regarding the content of the inorganic solid electrolyte in the composition containing the inorganic solid electrolyte, the total content of the active material and the inorganic solid electrolyte is preferably in the above range.

[0108] In the present invention, the solid components refer to the components that do not volatilize or evaporate and disappear when the composition containing the inorganic solid electrolyte 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 later.

[0109] <Polymer binder>

[0110] The composition containing the inorganic solid electrolyte of the present invention contains a polymer binder (also simply referred to as a binder). In the present invention, the polymer binder refers to a binder formed by including a polymer.

[0111] The polymer binder contained in the composition containing the inorganic solid electrolyte includes one or two or more fluorine-containing binders composed of fluorine copolymers satisfying the following (1) to (3). And the polymer binder contained in the composition containing the inorganic solid electrolyte preferably contains a polymer binder other than the fluorine-containing binder, for example, the granular polymer binder described later (preferably a granular polymer binder having an adsorption rate of 60% or more with respect to the inorganic solid electrolyte in the composition), a chain polymerization-based polymer binder (for example, a binder composed of a hydrocarbon-based polymer, a binder composed of a (meth)acrylic acid-based polymer, a polymer binder composed of an ethylene-based polymer). In addition, if the adsorption rate with respect to the inorganic solid electrolyte in the composition is considered, the polymer binder contains, in addition to the fluorine-containing binder, a polymer binder with an adsorption rate of less than 60% (low adsorption binder) and a polymer binder with an adsorption rate of 60% or more (high adsorption binder).

[0112] (Fluorine-containing binder)

[0113] First, the fluorine-containing binder contained as a polymer binder in the composition containing the inorganic solid electrolyte of the present invention will be described. The fluorine-containing binder is composed of a fluorine copolymer satisfying the following (1) to (3).

[0114] (1) As a constituent component, it contains a vinylidene fluoride constituent component and a hexafluoropropylene constituent component

[0115] (2) The content of the hexafluoropropylene constituent component in the fluorine-based copolymer is 21 to 65 mol%

[0116] (3) The tensile fracture strain is 500% or more

[0117] In the dispersion medium described below contained in the fluorine-containing adhesive in the composition, the adsorption rate with respect to the inorganic solid electrolyte is less than 60%.

[0118] The fluorine-containing adhesive is used in combination with solid particles such as an inorganic solid electrolyte in a composition containing a dispersion medium and an inorganic solid electrolyte, thereby enabling improvement of the dispersion stability and processability of the composition (slurry) containing the inorganic solid electrolyte.

[0119] In the present invention, the adsorption rate of the adhesive is a value measured using the inorganic solid electrolyte and the dispersion medium contained in the composition containing the inorganic solid electrolyte, and is an index indicating the degree of adsorption of the adhesive in the dispersion medium to the inorganic solid electrolyte. Here, the adsorption of the adhesive to the inorganic solid electrolyte includes not only physical adsorption but also chemical adsorption (adsorption through formation of chemical bonds, adsorption through electron donation and acceptance, etc.).

[0120] When the composition containing the inorganic solid electrolyte contains a plurality of inorganic solid electrolytes, it becomes the adsorption rate with respect to the inorganic solid electrolyte having the same composition (type and content) as the inorganic solid electrolyte in the composition containing the inorganic solid electrolyte. When the composition containing the inorganic solid electrolyte contains a plurality of dispersion media, the adsorption rate is similarly measured using a dispersion medium having the same composition (type and content) as the dispersion medium in the composition containing the inorganic solid electrolyte. And even when using a plurality of respective adhesives such as a fluorine-containing adhesive, a granular adhesive, and an adhesive composed of a chain polymerization-based polymer, for each adhesive, the adsorption rate for a plurality of adhesives is similarly set as in the composition containing the inorganic solid electrolyte and the like.

[0121] In the present invention, the adsorption rate of the adhesive is set as the value calculated by the method described in the examples.

[0122] The adsorption rate of the fluorine-containing binder relative to the inorganic solid electrolyte is less than 60%. If the fluorine-containing binder exhibits the above adsorption rate, over-adsorption to the inorganic solid electrolyte can be suppressed, and the dispersion stability and processability of the composition containing the inorganic solid electrolyte can be improved. From the viewpoint of achieving a higher level of both dispersion stability and processability, the adsorption rate is preferably 50% or less, more preferably 40% or less, further preferably 30% or less, particularly preferably 10% or less, and most preferably less than 5%. On the other hand, the lower limit of the adsorption rate is not particularly limited and can also be set to 0%. From the viewpoint of dispersion stability and processability, the lower limit of the adsorption rate is preferably small. On the other hand, from the viewpoint of improving the adhesion of the inorganic solid electrolyte, it is preferably greater than 0%, more preferably 0.1% or more, and further preferably 0.5% or more.

[0123] In the present invention, the adsorption rate relative to the inorganic solid electrolyte can be appropriately set by the properties of the polymer (fluorine-based copolymer) forming the fluorine-containing binder (for example, the content of the hexafluoropropylene constituent, the weight-average molecular weight), the type or content of the functional groups possessed by the polymer, the form of the fluorine-containing binder (the amount dissolved in the dispersion medium), and the like.

[0124] The fluorine-containing binder may be soluble (soluble binder) or may not be soluble in the dispersion medium contained in the composition containing the inorganic solid electrolyte, but a soluble binder that is soluble in the dispersion medium is preferred. In the present invention, the binder being soluble in the dispersion medium means that the fluorine-containing binder is dissolved in the dispersion medium of the composition containing the inorganic solid electrolyte. For example, in the solubility measurement, the solubility is 80 mass% or more. The method for measuring the solubility is as described below.

[0125] That is, a prescribed amount of the binder to be measured is weighed in a glass bottle, 100 g of the dispersion medium contained in the composition containing the inorganic solid electrolyte is added thereto, and the mixture is stirred at a rotation speed of 80 rpm on a mixing rotor at a temperature of 25°C for 24 hours. The transmittance of the mixed solution after stirring for 24 hours thus obtained is measured under the following conditions. This test (transmittance measurement) is performed by changing the amount of the binder dissolved (the above prescribed amount), and the upper limit concentration X (mass%) at which the transmittance becomes 99.8% is set as the solubility of the binder in the above dispersion medium.

[0126] <Transmittance measurement conditions>

[0127] Dynamic light scattering (DLS) measurement

[0128] Apparatus: DLS measurement apparatus DLS-8000 manufactured by Otsuka Electronics Co., Ltd.

[0129] Laser wavelength, output: 488 nm / 100 mW

[0130] Sample cell: NMR tube

[0131] When the composition containing an inorganic solid electrolyte of the present invention contains an active material described below (when an active material layer is formed from the composition containing an inorganic solid electrolyte), the adsorption rate of the polymer binder to the active material is not particularly limited. From the viewpoints of enhancing the dispersion stability and processability of the composition containing an inorganic solid electrolyte and the adhesiveness of solid particles, it is preferably 90% or less, more preferably 0.1 to 50%, and further preferably 1 to 10%. In the present invention, the adsorption rate of the binder to the active material is a value measured using the active material and the dispersion medium contained in the composition containing an inorganic solid electrolyte, and is an index showing the degree of adsorption of the binder in the dispersion medium to the active material. Here, the adsorption of the binder to the active material includes not only physical adsorption but also chemical adsorption (adsorption through the formation of chemical bonds, adsorption through electron donation and acceptance, etc.). In the present invention, it is particularly preferred that the adsorption rate of the fluorine-containing binder to the active material is within the above range.

[0132] When the composition containing an inorganic solid electrolyte contains a plurality of active materials, contains a plurality of dispersion media, and further uses a plurality of binders, it is the same as the adsorption rate of the above binder to the inorganic solid electrolyte. In the present invention, the adsorption rate of the binder to the active material is set to the value calculated by the method described in the examples. In the present invention, the adsorption rate to the active material can be appropriately set in the same manner as the adsorption rate to the inorganic solid electrolyte.

[0133] - Polymer forming a fluorine-containing binder -

[0134] The polymer forming a fluorine-containing binder is a fluorine-based copolymer containing a vinylidene fluoride constituent and a hexafluoropropylene constituent in a specific content and showing a tensile fracture strain of 500% or more.

[0135] In the present invention, the fluorine-based copolymer means a copolymer having a vinylidene fluoride (VDF) constituent and a hexafluoropropylene (HFP) constituent, and a copolymer further having a constituent derived from a polymerizable compound copolymerizable with VDF and HFP (sometimes also referred to as other constituents). From the viewpoint of having such other constituents, for convenience, it is called a "fluorine-based copolymer".

[0136] The polymerizable compound copolymerizable with VDF and HFP is not particularly limited. For example, a polymerizable compound having at least one carbon-carbon unsaturated bond can be cited. More specifically, a polymerizable compound containing a fluorine atom (fluorine-containing polymerizable compound), a polymerizable compound not containing a fluorine atom, a polymerizable compound having a functional group selected from the following functional group group (a), etc. can be cited.

[0137] In addition to using copolymerizable polymerizable compounds, functional groups existing in the main chain, side chain, or terminal of the fluorine-based copolymer are used as reaction points to introduce functional group group (a), other components, etc. Specifically, the fluorine-based copolymer can be modified by the ene reaction of the double bond generated by the dehydrofluorination reaction of the VDF component of the fluorine-based copolymer, the ene-thiol reaction, or the ATRP (Atom Transfer Radical Polymerization) polymerization method using a copper catalyst.

[0138] The fluorine-based copolymer has a vinylidene fluoride (VDF) constituent and a hexafluoropropylene (HFP) constituent, and includes two modes: a mode having a constituent derived from a fluorine-containing polymerizable compound and a mode not having a constituent derived from a fluorine-containing polymerizable compound. In the present invention, the mode not having a constituent derived from a fluorine-containing polymerizable compound is one of the preferred modes. When introducing the following functional group (a), the mode having a constituent derived from a copolymerizable polymerizable compound, particularly a compound having a hydrogen atom bonded to a carbon atom forming a carbon-carbon unsaturated bond in a fluorine-containing polymerizable compound (such as vinyl fluoride) is one of the preferred modes.

[0139] The VDF constituent forming the fluorine-based copolymer is a constituent derived from vinylidene fluoride, represented by -CF2-CH2-. The HFP constituent is a constituent derived from hexafluoropropylene, represented by, for example, -CF2-CF(CF3)-.

[0140] The constituent derived from a fluorine-containing polymerizable compound that can form a fluorine-based copolymer is not particularly limited as long as it is a constituent derived from a fluorine-containing polymerizable compound other than the VDF constituent and other than the HFP constituent. The fluorine-containing polymerizable compound into which this constituent is introduced is, for example, a compound having a fluorine atom directly bonded or indirectly (such as via a linking group described later) bonded to a carbon-carbon unsaturated bond. The fluorine-containing polymerizable compound is not particularly limited, and examples thereof include fluorinated vinyl compounds such as tetrafluoroethylene, trifluoroethylene, vinyl fluoride, and chlorotrifluoroethylene, and perfluoroalkyl ether compounds such as trifluoromethyl vinyl ether and pentafluoroethyl vinyl ether.

[0141] Further, the fluorine-containing polymerizable compound includes a polymerizable compound (macromonomer) having a polymer chain bonded directly or indirectly (e.g., via a linking group described later) to a carbon-carbon unsaturated bond. For example, a compound obtained by substituting at least one hydrogen atom of the above fluorine-containing polymerizable compound with a polymer chain can be mentioned. The polymer chain is not particularly limited, and ordinary polymer components can be applied. For example, a polymer chain of a (meth)acrylic polymer, a polymer chain of an ethylene polymer, a polymer chain of polysiloxane, a polyalkylene ether chain, a hydrocarbon chain, etc. can be mentioned. The (meth)acrylic polymer and ethylene polymer constituting the polymer chain can be used without particular limitation the polymers described in the chain polymerization type polymer binder described later.

[0142] An example of a fluorine-based copolymer having a constituent component derived from a polymerizable compound having a polymer chain is shown below and in the examples. In the following copolymer, the number in the lower right of each constituent component represents the content (mol%) of the constituent component in the copolymer.

[0143] [Chemical formula 1]

[0144]

[0145] The constituent component derived from a polymerizable compound not containing a fluorine atom is a constituent component capable of copolymerizing with vinylidene fluoride or hexafluoropropylene, and it is sufficient as long as it is a constituent component derived from a compound not having a fluorine atom and a functional group selected from the following functional group group (a), and there is no particular limitation. As the polymerizable compound not containing a fluorine atom into which this constituent component is introduced, polymerizable compounds usually used for chain polymerization can be mentioned. Specifically, vinyl compounds (M2), diene compounds, etc. described later can be mentioned.

[0146] The constituent component derived from a polymerizable compound not having a functional group selected from the functional group group (a) is not particularly limited as long as it is a constituent component having the above functional group. For example, vinyl compounds, diene compounds, etc. that may or may not have a fluorine atom can be mentioned. As the polymerizable compound having a functional group into which this constituent component is introduced, polymerizable compounds having the above functional group among polymerizable compounds usually used for chain polymerization can be mentioned, and the details thereof will be described later.

[0147] The VDF constituent component and other constituent components forming the fluorine-based copolymer may each have a substituent. As the substituent, there is no particular limitation as long as it is within the range not departing from the category of each constituent component. For example, a group selected from the following substituents Z, a functional group selected from the following functional group group (a) can be mentioned. Further, when the VDF constituent component or the like has a functional group selected from the functional group group (a), it is classified as the above "constituent component derived from a polymerizable compound having a functional group".

[0148] The fluorine-based copolymer used in the present invention may be any of block copolymers, alternating copolymers, and random copolymers of the above-described respective constituent components, and from the viewpoint of solubility, a random copolymer is preferred.

[0149] Such a fluorine-based copolymer can be appropriately synthesized or a commercially available product can also be used.

[0150] The fluorine-based copolymer forming the fluorine-containing adhesive may be one kind or two or more kinds.

[0151] In the fluorine-based copolymer, the content of the HFP constituent component (also referred to as the HFP amount) is 21 to 65 mol% in all the constituent components constituting the fluorine-based copolymer. Thereby, the action of the fluorine-containing adhesive composed of the fluorine-based copolymer with respect to the inorganic solid electrolyte can be weakened, and it helps to improve the dispersion stability and processability. And the above adsorption rate can be reduced to less than 60%. From the viewpoints of improving the dispersion stability and processability and further enhancing the collector adhesion, the upper limit of the HFP amount is preferably 60 mol% or less, more preferably 50 mol% or less, further preferably 45 mol% or less, and further preferably 40 mol% or less. On the other hand, from the viewpoints of improving the dispersion stability and processability and further enhancing the collector adhesion, the lower limit of the HFP amount is preferably 25 mol% or more, more preferably 30 mol% or more, and further preferably 35 mol% or more. Among them, when the weight-average molecular weight of the fluorine-based copolymer is 400,000 or more, if the lower limit of the HFP amount is 21 mol% or more, it is not necessary to set it to 25 mol% or more, 30 mol% or more, etc., and it is preferably set to 22 mol% or more. The HFP amount of the fluorine-based copolymer can be determined by measuring the nuclear magnetic resonance (NMR) spectrum (NMR measurement method) of the copolymer. In addition, for the fluorine-based copolymer of the composition, for example, the fluorine-based copolymer extracted with tetrahydrofuran (THF) is used for measurement. And for the fluorine-based copolymer in the sheet for all-solid-state secondary battery or the constituent layer of the all-solid-state secondary battery, for example, the constituent layer obtained by decomposing the sheet or the battery with THF and peeling off the constituent layer containing the polymer binder is used for measurement with the extracted fluorine-based copolymer.

[0152] In the fluorine-based copolymer, the content of the VDF constituent component (also referred to as the VDF amount) is not particularly limited, and from the viewpoints of improving the dispersion stability and processability and further enhancing the collector adhesion, in all the constituent components constituting the fluorine-based copolymer, it is preferably 30 to 90 mol%, more preferably 40 to 80 mol%, and further preferably 50 to 75 mol%. The VDF amount can be measured using the fluorine-based copolymer extracted in the same manner as the measurement of the HFP amount and according to the NMR measurement method.

[0153] In addition, in the fluorine-based copolymer, the ratio of the amount of VDF to the amount of HFP (amount of VDF / amount of HFP) is not particularly limited. From the viewpoints of improving dispersion stability and processability and further enhancing the adhesion to the current collector, it is preferably 0.5 to 5, more preferably 1 to 4, and still more preferably 1 to 3.

[0154] In the fluorine-based copolymer, the total content of the constituent components derived from copolymerizable polymerizable compounds is not particularly limited. For example, it can be set to 50 mol% or less.

[0155] In the copolymerizable polymerizable compounds, the contents of the constituent components derived from fluorine-containing polymerizable compounds or polymerizable compounds not containing fluorine atoms are appropriately set within the range that does not impair the excellent dispersion stability and processability, considering the adsorption rate or tensile fracture strain of the fluorine-based binder, the adhesion of solid particles, etc. The content of the constituent component derived from the fluorine-containing polymerizable compound is preferably 0 to 45 mol%, more preferably 2 to 40 mol% in all the constituent components constituting the fluorine-based copolymer. The content of the constituent component derived from the polymerizable compound not containing fluorine atoms is preferably 0 to 30 mol%, more preferably 1 to 25 mol% in all the constituent components constituting the fluorine-based copolymer.

[0156] The content of the constituent component (constituent component having a functional group) derived from the polymerizable compound having a functional group selected from the functional group group (a) can be appropriately determined in consideration of the adsorption rate or tensile fracture strain of the fluorine-based binder, the adhesion of solid particles, etc. For example, from the viewpoint of being able to maintain excellent dispersion stability and processability while making the adhesion of solid particles and the adhesion to the current collector stronger, in all the constituent components constituting the fluorine-based copolymer, it is preferably 0.01 to 10 mol%, and the lower limit value is more preferably 0.02 mol% or more, still more preferably 0.05 mol% or more, and particularly preferably 0.1 mol% or more. The upper limit value is more preferably 8 mol% or less, still more preferably 5 mol% or less, and particularly preferably 2 mol% or less.

[0157] When the fluorine-based copolymer has multiple constituent components having functional groups, the content of the constituent components having functional groups is set as the total amount. And when one constituent component has multiple or various functional groups, the content of the constituent component having functional groups generally refers to the content of that constituent component. However, in the present invention, for the sake of convenience, according to the relationship with the adsorption rate of the adhesive composed of the fluorine-based copolymer, the bonding force of solid particles, etc., it is set as the total amount of the content of each functional group. At this time, the sum of the contents of all constituent components constituting the fluorine-based copolymer exceeds 100 mol%. Among them, when multiple or various functional groups are present in one molecular chain (such as a linear molecular chain, etc.) (for example, 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 various functional groups are summarized as one functional group and included in the total amount. For example, in the polymer S-21 synthesized in the examples, one constituent component has an ester group and a carboxyl group. Therefore, the content of the constituent component having an ester group and a carboxyl group is not set to 0.3 mol% respectively (total 0.6 mol%), but the ester group and the carboxyl group are summarized as one functional group and the content of this constituent component is set to 0.3 mol%.

[0158] The fluorine-based copolymer preferably contains a constituent component (constituent component having a functional group) having a functional group selected from the following functional group group (a) as a substituent, for example. The constituent component having a functional group has the function of improving the adsorption rate of the adhesive to the inorganic solid electrolyte. The constituent component having this functional group includes, in addition to the constituent component derived from the polymerizable compound having a functional group, the constituent component derived from the polymerizable compound constituting the functional group as a copolymerizable compound. As the constituent component derived from the polymerizable compound constituting the functional group, for example, a constituent component derived from a polymerizable carboxylic anhydride such as maleic anhydride can be cited. In addition, the constituent component having a functional group includes, for example, a constituent component copolymerized with vinylidene fluoride and hexafluoropropylene, or a constituent component obtained by introducing a functional group selected from the following functional group group (a) into the constituent component introduced from the vinylidene fluoride constituent component (such as dehydrofluorination) through various reactions (such as the copolymerization components of the polymers S-18 to S-24 synthesized in the examples).

[0159] The above functional group can be possessed by any constituent component forming the fluorine-based copolymer, and is preferably possessed by a constituent component other than the VDF constituent component, the HFP constituent component, and the constituent component derived from the polymerizable compound not containing a fluorine atom. As a preferred constituent component having the above functional group, for example, a constituent component derived from a fluorine-containing polymerizable compound can be cited. The functional group can be incorporated into the main chain of the polymer or into the side chain. When incorporated into the side chain, it includes the mode of bonding directly or via a linking group with the atoms forming the main chain of the polymer, and the mode in which the polymer chain of the macromonomer constituting the side chain has the above functional group.

[0160] In the present invention, the main chain of a polymer refers to a linear molecular chain that constitutes the polymer and to which all other molecular chains can be regarded as side chains or comb-shaped chains relative to the main chain. Although it depends on the mass average molecular weight of the molecular chains regarded as side chains or comb-shaped chains, typically, the longest chain among the molecular chains constituting the polymer becomes the main chain. However, the end groups possessed by the polymer terminal are not included in the main chain. Further, the side chain of a polymer refers to a molecular chain other than the main chain, including short molecular chains and long molecular chains.

[0161] <Functional group group (a)>

[0162] Hydroxyl group, amino group, carboxyl group, sulfo group, phosphoric acid group, phosphonic acid group, thioalkyl group, ether bond (-O-), imino group (=NR, -NR-), ester bond (-CO-O-), amide bond (-CO-NR-), urethane bond (-NR-CO-O-), urea bond (-NR-CO-NR-), heterocyclic group, aryl group, carboxylic anhydride group, isocyanate group (-NCO), alkoxysilyl group, fluoroalkyl group, siloxanyl group

[0163] The amino group, sulfo group, phosphoric acid group (phosphoryl group), heterocyclic group, aryl group, and alkoxysilyl group contained in the functional group group (a) are not particularly limited and have the same meaning as the corresponding groups of the substituent Z described later. 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. The phosphonic acid group is not particularly limited, and examples thereof include a phosphonic acid group having 0 to 20 carbon atoms. The hydroxyl group, amino group, carboxyl group, sulfo group, phosphoric acid group, phosphonic acid group, and thioalkyl group can form salts. The fluoroalkyl group is a group obtained by substituting at least one hydrogen atom in an alkyl group or cycloalkyl group with a fluorine atom, and the number of carbon atoms thereof is preferably 1 to 20, more preferably 2 to 15, and further preferably 3 to 10. The number of fluorine atoms on the carbon atom may be a part of the substituted hydrogen atoms or all of them may be substituted (perfluoroalkyl group).

[0164] The siloxanyl group is not particularly limited, and for example, a group having a structure represented by -(SiR2-O)n- is preferred. The average repeat number n is preferably 1 to 100, more preferably 5 to 50, and further preferably 10 to 30.

[0165] The constituent having an ester bond (except for the ester bond forming a carboxyl group) or an amide bond as a functional group refers to a constituent in which the ester bond or amide bond is not directly bonded to the atom constituting the main chain. For example, it does not include a constituent derived from an alkyl (meth)acrylate.

[0166] R in each bond represents a hydrogen atom or a substituent, and a hydrogen atom is preferred. The substituent is not particularly limited and is selected from the substituent Z described later, and an alkyl group is preferred.

[0167] The carboxylic anhydride group is not particularly limited and includes a group formed by removing one or more hydrogen atoms from a carboxylic anhydride (e.g., a group represented by the following formula (2a)), and further a constituent itself obtained by copolymerizing a polymerizable carboxylic anhydride as a copolymerizable compound (e.g., a constituent represented by the following formula (2b)). As the group formed by removing one or more hydrogen atoms from a carboxylic anhydride, a group formed by removing one or more hydrogen atoms from a cyclic carboxylic anhydride is preferred. The carboxylic anhydride group derived from a cyclic carboxylic anhydride also corresponds to a heterocyclic group, but in the present invention, it is classified as a carboxylic anhydride group in the functional group group (a). For example, non-cyclic carboxylic anhydrides such as acetic anhydride, propionic anhydride, and benzoic anhydride, and cyclic carboxylic anhydrides such as maleic anhydride, phthalic anhydride, fumaric anhydride, succinic anhydride, and itaconic anhydride can be mentioned. The polymerizable carboxylic anhydride is not particularly limited, and a carboxylic anhydride having an unsaturated bond in the molecule can be mentioned, and a polymerizable cyclic carboxylic anhydride is preferred. Specifically, maleic anhydride and the like can be mentioned.

[0168] As an example of the carboxylic anhydride group, a group represented by the following formula (2a) or a constituent represented by formula (2b) can be mentioned, but the present invention is not limited to these. In each formula, * represents a bonding position.

[0169] [Chemical formula 2]

[0170]

[0171] As the functional group selected from the functional group group (a), a hydroxyl group, a carboxyl group, a phosphonic acid group, a heterocyclic group, and a carboxylic anhydride group are preferred, and a carboxylic anhydride group is more preferred.

[0172] There is no particular limitation on the method of incorporating a functional group into a polymer chain. For example, a method of using a polymerizable compound (a polymerizable compound having a functional group) that can copolymerize with a polymerizable compound having a functional group selected from the functional group group (a), a method of using a polymerization initiator or a chain transfer agent having (generating) the above functional group, a method using a polymer reaction, an ene reaction in a double bond generated by a dehydrofluorination reaction of a VDF component of a fluorine-based copolymer, an ene-thiol reaction, or an ATRP (Atom Transfer Radical Polymerization) polymerization method using a copper catalyst can be mentioned.

[0173] The polymerizable compound having the above functional groups is not particularly limited. For example, a polymerizable compound having at least one carbon-carbon unsaturated bond and the above functional groups can be cited. For example, a compound in which a carbon-carbon unsaturated bond is directly bonded to the above functional group, a compound in which a carbon-carbon unsaturated bond is bonded to the above functional group via a linking group, and further a compound in which the functional group itself contains a carbon-carbon unsaturated bond (for example, the above polymerizable cyclic carboxylic anhydride). In addition, the compound having the above functional group includes a compound capable of introducing a functional group into a component copolymerized with VDF and HFP or a component introduced from a VDF component (for example, dehydrofluorination) through various reactions. As such a compound, for example, each compound (including polymers) of an alcohol, an amino group, a mercapto group, or an epoxy group capable of undergoing an addition reaction or a condensation reaction with a component derived from a carboxylic anhydride, a component having a carbon-carbon unsaturated bond (for example, a dehydrofluorinated VDF component), etc. can be cited. Specifically, the compounds A-32 to A-76 exemplified below, and the following macromonomers, etc. can be cited. In addition, as the compound having the above functional group, a compound in which a carbon-carbon unsaturated bond is directly or via a linking group bonded to a macromonomer in which a functional group is incorporated as a substituent in a polymer chain is also included (for example, the compound A-31 etc. exemplified below). The macromonomer for introducing the macromonomer component can be appropriately determined according to the type of the polymer main chain forming the adhesive, etc., and is not unique. For example, a macromonomer having a polymer chain of a chain polymerization polymer described later can be cited.

[0174] Among them, a polymer chain composed of a (meth)acrylic acid polymer, etc. is preferred, and it preferably has a component derived from the (meth)acrylic acid compound (M1) described later, a component derived from the polymerizable compound (M2) described later, etc. The (meth)acrylic acid compound (M1) is not particularly limited. For example, a (meth)acrylic acid compound, a (meth)acrylate compound, a (meth)acrylamide compound, a (meth)acrylonitrile compound, etc. can be cited. It is one of the preferred modes that the alkyl group of the (meth)acrylic acid alkyl ester compound constituting the polymer chain is the above fluorinated alkyl group. And when the polymer chain having the (meth)acrylic acid alkyl ester compound has a plurality of (meth)acrylate compounds, at least one is a (meth)acrylic acid fluoroalkyl ester compound, and the number of carbon atoms of the alkyl group in at least one other (meth)acrylic acid alkyl ester compound is preferably 3 to 20, more preferably 4 to 16, and further preferably 6 to 14. The content of the other polymerizable compound (M2) in the (meth)acrylic acid polymer is not particularly limited. For example, it can be set to less than 50 mol%.

[0175] The number average molecular weight of the macromonomer is not particularly limited. From the viewpoint of maintaining excellent dispersion stability and processability while making the cohesive force of the solid particles and the adhesion to the current collector stronger, it is preferably 500 to 100,000, more preferably 1,000 to 50,000, and further preferably 2,000 to 20,000. Moreover, the content of the repeating unit having a functional group incorporated in the macromonomer is preferably 1 to 100 mol%, more preferably 3 to 80 mol%, and further preferably 5 to 70 mol%. The content of the repeating unit having no functional group is preferably 0 to 90 mol%, more preferably 0 to 70 mol%, and further preferably 0 to 50 mol%. Any component can be selected from the viewpoint of solubility and the like.

[0176] As the compound having a functional group, a compound in which the functional group itself contains a carbon-carbon unsaturated bond is preferred, and maleic anhydride is more preferred.

[0177] The carbon-carbon unsaturated bond is not particularly limited, and examples thereof include a vinyl group and a (meth)acryloyl group.

[0178] The linking group connecting the carbon-carbon unsaturated bond and the above functional group is not particularly limited, and examples thereof include an alkylene group (preferably having 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and further 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 -), a carbonyl group, a phosphoric acid linking group (-O-P(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 the linking group, a group formed by combining an alkylene group, an arylene group, a carbonyl group, an oxygen atom, a sulfur atom, and an imino group is preferred, a group formed by combining 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 and a -CO-N(R N )- group (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.) is further preferred, and a group formed by combining a -CO-O- group or a -CO-N(R N )- group with an alkylene group or a polyalkyleneoxy chain is particularly preferred. The above linking group may have a group other than the functional group selected from the functional group group (a). The number of atoms constituting the linking group and the number of linking atoms are as described later. Among them, for the polyalkyleneoxy chain constituting the linking group, it is not limited to the above. As the group other than the above functional group, a substituent Z described later can be mentioned, and examples thereof include an alkyl group or a halogen atom.

[0179] In the present invention, the number of atoms constituting the linking group is preferably from 1 to 36, more preferably from 1 to 24, still more preferably from 1 to 12, and particularly preferably from 1 to 6. The number of linking 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 linking atoms refers to the minimum number of atoms connecting between 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 linking atoms becomes 3.

[0180] The functional group(s) possessed by one kind of constituent may be one kind or two or more kinds. When there are two or more kinds, they may or may not be bonded to each other.

[0181] As the compound having a functional group, one preferred mode is a compound capable of introducing a functional group into a constituent derived from a VDF constituent through various reactions.

[0182] As the compound having a functional group, for example, it may be mentioned (meth)acrylic compounds such as (meth)acrylic acid compounds, (meth)acrylate compounds, (meth)acrylamide compounds, etc. (meth)acrylic compounds (M1) and compounds having the above-mentioned functional group, aromatic vinyl compounds including vinylnaphthalene compounds, vinylcarbazole compounds, etc., allyl compounds, vinyl ether compounds, vinyl ester compounds, etc. polymerizable compounds (M2) and compounds having the above-mentioned functional group.

[0183] The following shows specific examples of the polymerizable compound having a functional group and the compound capable of introducing a functional group, but is not limited thereto.

[0184] [Chemical formula 3]

[0185]

[0186] [Chemical formula 4]

[0187]

[0188] [Chemical formula 5]

[0189]

[0190] - Substituent Z -

[0191] Examples include alkyl groups (preferably alkyl groups having 1 to 20 carbon atoms, such as 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, such as vinyl, allyl, oleyl, etc.), alkynyl groups (preferably alkynyl groups having 2 to 20 carbon atoms, such as ethynyl, butadiynyl, phenylethynyl, etc.), cycloalkyl groups (preferably cycloalkyl groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc. In this specification, when referring to an alkyl group, it generally includes cycloalkyl groups, but is separately described here.), aryl groups (preferably aryl groups having 6 to 26 carbon atoms, such as phenyl, 1-naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methylphenyl, etc.), aralkyl groups (preferably aralkyl groups having 7 to 23 carbon atoms, such as benzyl, phenethyl, etc.), heterocyclic groups (preferably heterocyclic groups having 2 to 20 carbon atoms, more preferably 5- or 6-membered heterocyclic groups having at least one oxygen atom, sulfur atom, or nitrogen atom. Heterocyclic groups include aromatic heterocyclic groups and aliphatic heterocyclic groups. For example, tetrahydropyranyl group, tetrahydrofuranyl group, 2-pyridyl group, 4-pyridyl group, 2-imidazolyl group, 2-benzimidazolyl group, 2-thiazolyl group, 2-oxazolyl group, pyrrolidinone group, etc.), alkoxy groups (preferably alkoxy groups having 1 to 20 carbon atoms, such as methoxy, ethoxy, isopropoxy, benzyloxy, etc.), aryloxy groups (preferably aryloxy groups having 6 to 26 carbon atoms, such as phenoxy, 1-naphthyloxy, 3-methylphenoxy, 4-methoxyphenoxy, etc. In this specification, when referring to an aryloxy group, it means including arylacyloxy groups.), heterocyclic oxy groups (groups in which an -O- group is bonded to the above heterocyclic group), alkoxycarbonyl groups (preferably alkoxycarbonyl groups having 2 to 20 carbon atoms, such as ethoxycarbonyl, 2-ethylhexyloxycarbonyl, dodecyloxycarbonyl, etc.), aryloxycarbonyl groups (preferably aryloxycarbonyl groups having 6 to 26 carbon atoms, such as phenoxycarbonyl, 1-naphthyloxycarbonyl, 3-methylphenoxycarbonyl, 4-methoxyphenoxycarbonyl, etc.), heterocyclic oxycarbonyl groups (groups formed by bonding an -O-CO- group to the above heterocyclic group), amino groups (preferably including amino groups having 0 to 20 carbon atoms, alkylamino groups, arylamino groups, such as amino (-NH2), N,N-dimethylamino, N,N-diethylamino, N-ethylamino, anilino, etc.), sulfamoyl groups (preferably sulfamoyl groups having 0 to 20 carbon atoms, such as N,N-dimethylsulfamoyl, N-phenylsulfamoyl, etc.), acyl groups (including alkylcarbonyl, alkenylcarbonyl, alkynylcarbonyl, arylcarbonyl, heterocycliccarbonyl, preferably acyl groups having 1 to 20 carbon atoms, such as acetyl, propionyl, butyryl, octanoyl, hexadecanoyl, acryloyl, methacryloyl, crotonoyl, benzoyl, naphthoyl, nicotinoyl, etc.), acyloxy groups (including alkylcarbonyloxy, alkenylcarbonyloxy, alkynylcarbonyloxy, arylcarbonyloxy, heterocycliccarbonyloxy, preferably acyloxy groups having 1 to 20 carbon atoms, such as acetyloxy, propionyloxy, butyryloxy, octanoyloxy, hexadecanoyloxy, acryloyloxy, methacryloyloxy, crotonoyloxy, benzoyloxy, naphthoyloxy, nicotinoyloxy, etc.), aromatic acyloxy groups (preferably aromatic acyloxy groups having 7 to 23 carbon atoms, such as benzoyloxy, etc.), carbamoyl groups (preferably carbamoyl groups having 1 to 20 carbon atoms, such as N,N-dimethylcarbamoyl, N-phenylcarbamoyl, etc.), acylamino groups (preferably acylamino groups having 1 to 20 carbon atoms, such as acetylamino, benzoylamino, etc.), alkylthio groups (preferably alkylthio groups having 1 to 20 carbon atoms, such as methylthio, ethylthio, isopropylthio, benzylthio, etc.), arylthio groups (preferably arylthio groups having 6 to 26 carbon atoms, such as phenylthio, 1-naphthylthio, 3-methylphenylthio, 4-methoxyphenylthio, etc.), heterocyclicthio groups (groups in which the -S- group is bonded to the above-mentioned heterocyclic groups), alkylsulfonyl groups (preferably alkylsulfonyl groups having 1 to 20 carbon atoms, such as methylsulfonyl, ethylsulfonyl, etc.), arylsulfonyl groups (preferably arylsulfonyl groups having 6 to 22 carbon atoms, such as benzenesulfonyl, etc.), alkylsilyl groups (preferably alkylsilyl groups having 1 to 20 carbon atoms, such as monomethylsilyl, dimethylsilyl, trimethylsilyl, triethylsilyl, etc.), arylsilyl groups (preferably arylsilyl groups having 6 to 42 carbon atoms, such as triphenylsilyl, etc.), alkoxysilyl groups (preferably alkoxysilyl groups having 1 to 20 carbon atoms, such as monomethoxysilyl, dimethoxysilyl, trimethoxysilyl, triethoxysilyl, etc.), aryloxysilyl groups (preferably aryloxysilyl groups having 6 to 42 carbon atoms, such as triphenoxysilyl, etc.), phosphoryl groups (preferably phosphoryl groups having 0 to 20 carbon atoms, such as -OP(=O)(R, P )2), phosphonyl groups (preferably phosphonyl groups having 0 to 20 carbon atoms, such as -P(=O)(R P )2), phosphinyl groups (preferably phosphinyl groups having 0 to 20 carbon atoms, such as -P(R P )2), phosphonic acid groups (preferably phosphonic acid groups having 0 to 20 carbon atoms, such as -PO(OR P )2) sulfo group (sulfonic acid group), carboxyl group, hydroxyl group, thioalkyl 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 substituents Z).

[0192] Moreover, each group listed in these substituents Z may be further substituted by the above-mentioned substituent Z.

[0193] The above-mentioned alkyl group, alkylene group, alkenyl group, alkenylene group, alkynyl group and / or alkynylene group, etc. can be cyclic or chain-like, and can be straight-chain or branched-chain.

[0194] When synthesizing a fluorine-based copolymer, the polymerization method of the raw material compounds (VDF, HFP and copolymerizable polymerizable compounds) is not particularly limited, and a known method is selected and the conditions can be appropriately set.

[0195] (Physical properties or characteristics of a fluorine-containing adhesive or a fluorine-based copolymer forming a fluorine-containing adhesive, etc.)

[0196] The fluorine-containing adhesive (fluorine-based copolymer) is not particularly limited, and the peel strength with respect to the aluminum foil is preferably 0.1 N / mm or more. Thereby, it is possible to impart firm collector adhesion to the active material layer and contribute to further improving the cycle characteristics of the all-solid-state secondary battery. From the viewpoint of further improving the collector adhesion and cycle characteristics, the peel strength of the fluorine-based copolymer is more preferably 0.2 N / mm or more, and further preferably 0.3 N / mm or more. The upper limit is not particularly limited. For example, in practice, it is 10 N / mm or less, preferably 2.0 N / mm or less. In the present invention, the peel strength can be appropriately set by changing the composition of the fluorine-based copolymer, changing the physical properties of the fluorine-containing adhesive, etc.

[0197] A solution (solid content concentration: 10% by mass) obtained by dissolving a fluorine-containing adhesive in an organic solvent (butyl butyrate) was dropped on an aluminum foil (trade name: A1N30, manufactured by Hohsen Corp.) and then dried (temperature: 100 °C, time: 180 minutes) to produce a dried film with a thickness of 50 μm (width: 10 mm, length: 50 mm). This was used as a test piece to measure the peel strength. Regarding the measurement method and conditions, a tensile tester (ZTS-50N, manufactured by IMADACO., LTD.) was used to measure the peel force when the obtained dried film was peeled from the coating surface of the aluminum foil in the direction of 90° at a speed of 30 mm / s, and the average value thereof was set as the peel strength (unit: N / mm).

[0198] The water concentration of the fluorine-containing adhesive (fluorine-based copolymer) is preferably 100 ppm (mass basis) or less. And this fluorine-containing adhesive can crystallize and dry the fluorine-based copolymer, or can directly use a fluorine-containing adhesive dispersion.

[0199] The fluorine-based copolymer is preferably amorphous. In the present invention, a polymer being "amorphous" typically means that no endothermic peak due to crystal melting is observed when measured at the glass transition temperature.

[0200] When the fluorine-containing binder is in the form of particles, its shape is not particularly limited and may be flat, amorphous, etc., and spherical or granular shapes are preferred. Its average primary particle size is not particularly limited, preferably 0.1 nm or more, more preferably 1 nm or more, further preferably 5 nm or more, particularly preferably 10 nm or more, and most preferably 50 nm or more. As the upper limit value, it is preferably 5.0 μm or less, more preferably 1 μm or less, further preferably 700 nm or less, and particularly preferably 500 nm or less.

[0201] The average particle size of the fluorine-containing binder can be measured in the same manner as the average particle size of the above-mentioned inorganic solid electrolyte.

[0202] In addition, the average particle size of the fluorine-containing binder in the constituent layer of the all-solid-state secondary battery can be measured, for example, as follows: After disassembling the battery and peeling off the constituent layer containing the fluorine-containing binder, the constituent layer is measured, and the measured values of the particle sizes of the particles other than the fluorine-containing binder that have been previously measured are removed.

[0203] For example, the average particle size of the fluorine-containing binder can be adjusted by the type of dispersion medium, the content of the constituent components in the polymer, etc.

[0204] The tensile fracture strain of the fluorine-based copolymer forming the fluorine-containing binder is 500% or more. If the above-mentioned specific fluorine-based copolymer shows a tensile fracture strain of 500% or more, in the composition containing the inorganic solid electrolyte, as described above, the interaction between solid particles can be maintained, the repulsive force between fluorine atoms can effectively act on the solid particles, the dispersion stability or processability can be improved, the adhesion of the solid particles can be made firm, and the cycle characteristics can be further improved. In the present invention, the tensile fracture strain is more preferably 600% or more, further preferably 700% or more, particularly preferably 750% or more, and most preferably 2500% or more. The upper limit value of the tensile fracture strain is not particularly limited and is actually 10000%, preferably 6000% or less, and more preferably 3500% or less.

[0205] In the present invention, the tensile fracture strain can be appropriately set by changing the molecular weight of the fluorine-based copolymer, etc.

[0206] The tensile fracture strain is measured by preparing a test piece described in Japanese Industrial Standard (JIS) K 7161 (2014) "Plastics - Methods for Determining Tensile Properties" and according to the methods and conditions described in this standard. Specifically, a solution obtained by dissolving a fluorine-based copolymer in, for example, DIBK or the like is used to prepare a cast film with a thickness of about 200 μm. The cast film is cut into a size of 10 mm × 20 mm, set on a tensile testing machine so that the chuck distance (distance between jigs) becomes 10 mm, and a tensile test (stress and strain line evaluation) is carried out at a test speed of 30 mm / min, thereby enabling the tensile fracture strain to be obtained. The tensile fracture strain is a value obtained by setting the length of the test piece before stretching to 100% and subtracting 100% from the length of the test piece at the time of fracture (elongation amount during stretching).

[0207] The weight average molecular weight of the fluorine-based copolymer is not particularly limited, and is preferably 50,000 to 1,500,000. If the fluorine-based copolymer has a weight average molecular weight within the above range, the dispersion stability and processability can be further improved, and furthermore, the tensile fracture strain can be increased. From the viewpoint that the tensile fracture strain increases due to the extension of the main chain of the copolymer, and thus the dispersion stability and processability are improved, the larger the weight average molecular weight, the more preferable. For example, it is more preferably 70,000 or more, further preferably 80,000 or more, and particularly preferably 100,000 or more. If the weight average molecular weight of the fluorine-based copolymer is 400,000 or more, the cycle characteristics of the all-solid-state secondary battery can be further improved. It is considered that since the copolymer becomes a high molecular weight, the steric exclusion effect is further enhanced, thereby enabling the dispersion stability of the composition (slurry) containing the inorganic solid electrolyte and the dispersion uniformity of the solid particles in the formed layer to be improved. The upper limit is more preferably 1,500,000 or less, and further preferably 1,200,000 or less. In one embodiment of the present invention, the weight average molecular weight of the fluorine-based copolymer can be set to 1,000,000 or less, and can also be set to 900,000 or less.

[0208] -Measurement of molecular weight-

[0209] In the present invention, for the molecular weight of the polymer and the polymer chain, unless otherwise specified, it refers to the weight average molecular weight or number average molecular weight in terms of standard polystyrene obtained by gel permeation chromatography (GPC). As the measurement method, it is basically set to the value measured by the following Condition 1 or Condition 2 (preferably). Among them, an appropriate eluent can be selected according to the type of polymer and used.

[0210] (Condition 1)

[0211] Column: Connect 2 TOSOH TSKgel Super AWM-H (trade name, manufactured by TOSOH CORPORATION)

[0212] Carrier: 10 mM LiBr / N-methylpyrrolidone

[0213] Measurement temperature: 40 °C

[0214] Carrier flow rate: 1.0 ml / min

[0215] Sample concentration: 0.1 mass%

[0216] Detector: RI (refractive index) detector

[0217] (Condition 2)

[0218] Column: A column connecting TOSOH TSKgel Super HZM-H, TOSOH TSKgel Super HZ4000, and TOSOH TSKgel Super HZ2000 (all are product names, manufactured by Tosoh Corporation) was used.

[0219] Carrier: Tetrahydrofuran

[0220] Measurement temperature: 40 °C

[0221] Carrier flow rate: 1.0 ml / min

[0222] Sample concentration: 0.1 mass%

[0223] Detector: RI (refractive index) detector

[0224] From the viewpoint of the dispersion stability of the fluorine-based copolymer from solid particles, for example, the SP value is preferably 9 to 23, more preferably 10 to 18, and further preferably 11 to 15. The difference (absolute value) between the SP value of the fluorine-based copolymer and the dispersion medium will be described later.

[0225] In the present invention, as long as the SP value is not particularly limited, it is obtained by the Hoy method (refer to H.L. Hoy JOURNAL OF PAINT TECHNOLOGY Vol. 42, No. 541, 1970, 76 - 118 and POLYMER HANDBOOK 4 th 、Chapter 59, VII page 686 Table 5, Table 6, and the following formula in Table 6). And, the unit of the SP value is omitted, but its unit is MPa 1 / 2 。

[0226] [Mathematical formula 1]

[0227]

[0228] In the formula, δt Represents the SP value. F t Is the molar attraction function (J×cm 3 ) 1 / 2 / mol, and is represented by the following formula. V is the molar volume (cm 3 / mol), and is represented by the following formula. Is represented by the following formula.

[0229]

[0230] In the above formula, F t，i Represents the molar attraction function of each structural unit, V i Represents the molar volume of each structural unit, Δ(p) T，i Represents the correction value of each structural unit, n i Represents the number of each structural unit.

[0231] The SP value of the polymer is calculated using the components (derived from the raw material compounds) and their SP values by the following formula. In addition, the SP values of the components obtained according to the above literature are converted into SP values (MPa 1 / 2 )(For example, 1 cal 1 / 2 cm- 3 / 2 ≈2.05 J 1 / 2 cm- 3 / 2 ≈2.05 MPa 1 / 2 ) and used.

[0232] SP p 2 =(SP1 2 ×W1)+(SP2 2 ×W2)+……

[0233] In the formula, SP1, SP2... represent the SP values of the components, and W1, W2... represent the mass fractions of the components. In addition, the SP value of the VDF component is 13.1, and the SP value of the HFP component is 10.1.

[0234] In the present invention, the mass fraction of the component is the mass fraction of the component (raw material compound introducing the component) in the polymer.

[0235] The SP value of the fluorine-containing copolymer can be adjusted by the composition of the fluorine-containing copolymer (types and contents of components), etc.

[0236] The fluorine-containing copolymer preferably satisfies the above physical properties, etc., but from the viewpoints of dispersion stability, processability, adhesiveness, collector body adhesion, and resistance suppression, it is more preferably the polymer shown below (two modes).

[0237] A fluorine-based copolymer having an HFP content of 30 to 40 mol%, with a small amount (the above content) of a carboxylic anhydride group (preferably a maleic anhydride group) introduced as a functional group, and a tensile fracture strain of 2500 to 3500%, and a fluorine-based copolymer having an adsorption rate of the fluorine-containing binder to the inorganic solid electrolyte greater than 0% and less than 5%.

[0238] A fluorine-based copolymer having an HFP content of 21 to 40 mol%, preferably with a small amount (the above content) of a functional group (a) introduced, a tensile fracture strain of 500% or more, and a weight-average molecular weight of 400,000 or more, and a fluorine-based copolymer having an adsorption rate of the fluorine-containing binder to the inorganic solid electrolyte greater than 0% and less than 10%.

[0239] The fluorine-based copolymer forming the fluorine-containing binder can be a non-crosslinked polymer or a crosslinked polymer. Moreover, when crosslinking the polymer by heating or applying a voltage, the molecular weight can become greater than the above molecular weight. Preferably, when starting to use the all-solid-state secondary battery, the weight-average molecular weight of the polymer is in the above range.

[0240] The composition containing the inorganic solid electrolyte of the present invention can contain one kind of fluorine-containing binder or can contain a plurality of binders.

[0241] The content of the fluorine-containing binder in the composition containing the inorganic solid electrolyte is not particularly limited. From the viewpoints of improving dispersion stability and processability and then showing adhesiveness, in 100 mass% of the solid components, it is preferably 0.1 to 10.0 mass%, more preferably 0.2 to 5.0 mass%, and further preferably 0.3 to 4.0 mass%.

[0242] When the composition containing the inorganic solid electrolyte contains the granular binder described later, the content (solid component amount) of the fluorine-containing binder can be lower than the content (solid component amount) of the granular binder, but preferably the same or higher. Thereby, the adhesiveness can be further enhanced without impairing the excellent dispersion stability and processability. The difference (absolute value) between the content of the fluorine-containing binder and the content of the granular binder is not particularly limited. For example, it can be set to 0 to 8 mass%, more preferably 0 to 4 mass%, and further preferably 0 to 2 mass%. Moreover, the ratio of the content of the fluorine-containing binder to the content of the granular binder (content of the fluorine-containing binder / content of the granular binder) is not particularly limited. For example, it is preferably 0.01 to 10, more preferably 0.02 to 5.

[0243] When the composition containing an inorganic solid electrolyte contains a chain polymerization polymer binder composed of a chain polymerization polymer (excluding the above-mentioned fluorine-based copolymer), the content (solid content) of the fluorine-containing binder can be lower than the content (solid content) of the binder composed of the chain polymerization polymer, but it is preferably the same or higher. Thereby, the dispersion stability and the cycle characteristics can be further enhanced. The difference (absolute value) between the content of the fluorine-containing binder and the content of the polymer binder composed of the chain polymerization polymer is not particularly limited. For example, it can be set to 0 to 8% by mass, more preferably 0 to 4% by mass, and further preferably 0 to 2% by mass. Also, the ratio of the content of the fluorine-containing binder to the content of the chain polymerization polymer binder (content of the fluorine-containing binder / content of the chain polymerization polymer binder) is not particularly limited. For example, it is preferably 0.01 to 10, more preferably 0.02 to 5.0.

[0244] In the present invention, in 100% by mass of the solid content, the mass ratio of the total mass (total amount) of the inorganic solid electrolyte and the active material to the total mass of the polymer binder [(mass of the inorganic solid electrolyte + mass of the active material) / (total mass of the binder)] is preferably in the range of 1,000 to 1. This ratio is more preferably 500 to 2, and further preferably 100 to 10.

[0245] (Granular binder)

[0246] As the polymer binder in the composition containing an inorganic solid electrolyte of the present invention, in addition to the above-mentioned fluorine-containing binder, it preferably contains one or more granular polymer binders (granular binders) that are insoluble in the dispersion medium of the composition. The shape of the granular binder is not particularly limited and can be flat, amorphous, etc., and is preferably spherical or granular. The average particle diameter of the granular binder is preferably 1 to 1000 nm, more preferably 10 to 800 nm, further preferably 20 to 500 nm, and particularly preferably 40 to 300 nm. The average particle diameter can be measured in the same manner as the particle diameter of the above-mentioned inorganic solid electrolyte.

[0247] The granular binder is preferably a granular binder having an adsorption rate of 60% or more with respect to the inorganic solid electrolyte. The adsorption rate with respect to the active material can be appropriately determined. Each adsorption rate can be measured in the same manner as the fluorine-containing binder.

[0248] If the composition containing an inorganic solid electrolyte contains a granular binder, without impairing the improvement effect of the dispersion stability and processability based on the fluorine-containing binder, it is possible to suppress the increase in the interfacial resistance while enhancing the adhesion of the solid particles. As a result, for all-solid-state secondary batteries, the cycle characteristics can be further improved, and preferably, further low resistance can be achieved.

[0249] As the granular binder, various granular binders for manufacturing all-solid-state secondary batteries can be used without particular limitation. For example, granular binders composed of the following stepwise polymerization polymers or chain polymerization polymers can be mentioned. Specifically, polymer A-1, A-2, etc. synthesized in the examples can be mentioned. In addition, binders described in JP-A No. 2015-088486, WO 2018 / 020827, etc. can also be mentioned.

[0250] There is no particular limitation on the stepwise polymerization polymer. For example, polyurethane, polyurea, polyamide, polyimide, polyester, polycarbonate, etc. can be mentioned. There is no particular limitation on the chain polymerization polymer. For example, fluorine-based polymers (also called fluorine-based copolymers), hydrocarbon-based polymers, vinyl-based polymers, (meth)acrylic polymers, etc. can be mentioned as chain polymerization polymers (for example, polymers described later can be mentioned).

[0251] The content of the granular binder in the composition containing the inorganic solid electrolyte is not particularly limited. From the viewpoints of improving dispersion stability and processability and further showing adhesiveness, in 100% by mass of the solid component, it is preferably 0.02 to 5.0% by mass, more preferably 0.05 to 3.0% by mass, and further preferably 0.1 to 2.0% by mass. In addition, the content of the granular binder can be appropriately set within the above range, but considering the solubility of the granular binder, a content that is insoluble in the composition containing the inorganic solid electrolyte is preferred.

[0252] (Polymer binder composed of chain polymerization polymer)

[0253] The composition containing the inorganic solid electrolyte of the present invention preferably further contains one or more polymer binders composed of chain polymerization polymers in addition to the above-mentioned fluorine-containing binder as the polymer binder. If the composition containing the inorganic solid electrolyte contains a fluorine-containing binder, the dispersion stability can be further improved without impairing the processability, and the cycle characteristics can be further improved.

[0254] The polymer binder composed of this chain polymerization polymer (sometimes called a chain polymerization polymer binder) may not be soluble in the dispersion medium in the composition, but a soluble binder is preferred. In addition, the chain polymerization polymer binder preferably has an adsorption rate of less than 60% with respect to the inorganic solid electrolyte, and the preferred range is the same as that of the fluorine-containing binder. The adsorption rate to the active material can be appropriately determined. Each adsorption rate can be measured by the above method.

[0255] As the chain polymerization polymer that forms the chain polymerization polymer binder, as long as it is a chain polymerization polymer other than the fluorine-based copolymer that forms the above-mentioned fluorine-based binder, there is no particular limitation, and hydrocarbon polymers, vinyl polymers, and (meth)acrylic polymers can be preferably cited. The polymerization method of these chain polymerization polymers is not particularly limited, and it can be any one of block copolymers, alternating copolymers, and random copolymers.

[0256] The chain polymerization polymer may include a constituent component having a functional group selected from the above functional group group (a) as a substituent (constituent component having a functional group). The constituent component having a functional group has the function of improving the adsorption rate of the chain polymerization polymer binder to the inorganic solid electrolyte, and may also be any constituent component that forms the chain polymerization polymer. The functional group can be incorporated into the main chain of the chain polymerization polymer or into the side chain. When incorporated into the side chain, there is a linking group that bonds the functional group and the main chain. There is no particular limitation as the linking group, and a linking group that links a carbon-carbon unsaturated bond and the above functional group can be cited. The functional group possessed by one constituent component can be one or two or more. When there are two or more, they can be bonded to each other or not bonded.

[0257] The constituent component having an ester bond (except for the ester bond forming a carboxyl group) or an amide bond as the functional group means a constituent component in which the ester bond or amide bond is not directly bonded to the atom constituting the main chain. For example, it does not include a constituent component derived from an alkyl (meth)acrylate.

[0258] The content of the constituent component having the above functional group in the polymer is not particularly limited. From the viewpoint of the adhesiveness of solid particles, it is preferably 0.01 to 70 mol%, more preferably 5 to 50 mol%, and still more preferably 20 to 50 mol%.

[0259] As a method for introducing the functional group, for example, a method of reacting a compound introducing a constituent component with a compound containing the functional group (a) and copolymerizing them when polymerizing the chain polymerization polymer can be cited. In addition, a method of polymerizing with an initiator or a chain transfer agent containing a functional group to introduce a functional group at the polymer end, and a method of introducing a functional group into the side chain or the end by a polymer reaction can be cited. A commercially available chain polymerization polymer having a functional group can also be used.

[0260] - Hydrocarbon polymer binder composed of hydrocarbon polymers -

[0261] As hydrocarbon polymers for forming hydrocarbon polymer adhesives, examples include polyethylene, polypropylene, natural rubber, polybutadiene, polyisoprene, polystyrene, styrene-butadiene copolymer, styrenic thermoplastic elastomer, polybutene, acrylonitrile-butadiene copolymer, or hydrogenated (hydrogenated) polymers thereof. There is no particular limitation on the styrenic thermoplastic elastomer or its hydride. For example, styrene-ethylene-butene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), hydrogenated SIS, styrene-butadiene-styrene block copolymer (SBS), hydrogenated SBS, styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-butadiene rubber (SBR), hydrogenated styrene-butadiene rubber (HSBR), and random copolymers corresponding to the above block copolymers such as SEBS can be mentioned. In the present invention, the hydrocarbon polymer is preferably a polymer without unsaturated groups (such as 1,2-butadiene constituent) bonded to the main chain, which can inhibit the formation of chemical crosslinks.

[0262] As hydrocarbon polymers having the above functional groups, commercially available products can be used. For example, Tuftec M1911, Tuftec M1913 (trade names, manufactured by ASAHI KASEI CORPORATION), SUMIFITT series (manufactured by Sumika Chemtex Company, Limited), DYNARON 4630P, DYNARON 8630P (trade names, manufactured by JSR Corporation), Nipol LX series (manufactured by Zeon Corporation) can be mentioned.

[0263] -Ethylene-based polymer adhesives composed of ethylene-based polymers-

[0264] As ethylene-based polymers for forming ethylene-based polymer adhesives, for example, polymers containing 50 mol% or more of ethylene-based monomers other than (meth)acrylic acid compounds (M1) can be mentioned. As ethylene-based monomers, vinyl compounds described later can be mentioned. Specifically, as ethylene-based polymers, for example, polyvinyl alcohol, polyvinyl acetal, polyvinyl acetate, or copolymers containing these can be mentioned.

[0265] This vinyl polymer preferably has, in addition to the constituent components derived from vinyl monomers, constituent components derived from (meth)acrylic acid compound (M1) that form the following (meth)acrylic polymer. The content of the constituent components derived from vinyl monomers is preferably the same as the content of the constituent components derived from (meth)acrylic acid compound (M1) in the (meth)acrylic polymer. As long as the content of the constituent components derived from (meth)acrylic acid compound (M1) in the polymer is less than 50% by mass, there is no particular limitation, and it is preferably 0 to 30% by mass.

[0266] -(Meth)acrylic polymer adhesive composed of (meth)acrylic polymer-

[0267] As the (meth)acrylic polymer forming the (meth)acrylic polymer adhesive, for example, a polymer obtained by copolymerizing at least one (meth)acrylic acid compound (M1) selected from (meth)acrylic acid compounds, (meth)acrylate compounds, (meth)acrylamide compounds, and (meth)acrylonitrile compounds is preferably used. Further, a (meth)acrylic polymer composed of a copolymer of (meth)acrylic acid compound (M1) and other polymerizable compound (M2) is also preferably used. As the (meth)acrylate compound (M1), for example, (meth)acrylic acid alkyl ester compounds can be cited, and the number of carbon atoms of the alkyl group is not particularly limited, and can be set to 1 to 24, preferably 3 to 20, more preferably 4 to 16, and further preferably 6 to 14, for example.

[0268] There is no particular limitation on other polymerizable compound (M2), and vinyl compounds such as styrene compounds, vinyl naphthalene compounds, vinyl carbazole compounds, allyl compounds, vinyl ether compounds, vinyl ester compounds, dialkyl itaconates, and unsaturated carboxylic anhydrides can be cited. As the vinyl compound, for example, the "vinyl monomer" described in JP-A-2015-88486 can be cited.

[0269] The content of other polymerizable compound (M2) in the (meth)acrylic polymer is not particularly limited, and can be set to less than 50 mol%, for example.

[0270] The content of the chain polymerization type polymer adhesive in the composition containing the inorganic solid electrolyte is not particularly limited. From the viewpoint of being able to improve the dispersion stability, processability, and collector adhesion in a well-balanced manner, in 100% by mass of the solid content, it is preferably 0.02 to 5.0% by mass, more preferably 0.05 to 3.0% by mass, and further preferably 0.1 to 2.0% by mass.

[0271] (Combination of polymer adhesives)

[0272] The polymer binder contained in the composition containing an inorganic solid electrolyte of the present invention may contain at least one fluorine-containing binder as described above, or may contain two or more kinds.

[0273] As a way of containing a fluorine-containing binder as a polymer binder, there can be mentioned a way of containing only a fluorine-containing binder, a way of containing two or more kinds of fluorine-containing binders, a way of containing one kind or two or more kinds of fluorine-containing binders and a granular binder, and further, a way of containing a chain polymerization type polymer binder in each way, etc.

[0274] In the present invention, the chain polymerization type polymer binder contained in the polymer binder is at least one selected from the group consisting of a hydrocarbon type polymer binder, an ethylene type polymer binder, and a (meth)acrylic acid polymer binder.

[0275] The composition containing an inorganic solid electrolyte of the present invention may contain a binder other than the above-mentioned polymer binder and granular binder.

[0276] <Dispersion medium>

[0277] The composition containing an inorganic solid electrolyte of the present invention preferably contains a dispersion medium for dispersing the above-mentioned respective components.

[0278] As the dispersion medium, as long as it is an organic compound showing a liquid state in the use environment, 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. can be mentioned.

[0279] As the dispersion medium, it can be a non-polar dispersion medium (hydrophobic dispersion medium) or a polar dispersion medium (hydrophilic dispersion medium). From the viewpoint of being able to exhibit excellent dispersibility, a non-polar dispersion medium is preferred. As the non-polar dispersion medium, it generally refers to the property of low affinity for water, but in the present invention, for example, ester compounds, ketone compounds, ether compounds, aromatic compounds, aliphatic compounds, etc. can be mentioned.

[0280] As the alcohol compound, for example, 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, 1,4-butanediol can be listed.

[0281] As the ether compound, for example, 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.), cyclic ethers (tetrahydrofuran, dioxane (including various isomers of 1,2-, 1,3- and 1,4-), etc.) can be cited.

[0282] As the amide compound, for example, 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-methylpropanamide, hexamethylphosphoric triamide, etc. can be cited.

[0283] As the amine compound, for example, triethylamine, diisopropylethylamine, tri-n-butylamine, etc. can be cited.

[0284] As the ketone compound, for example, 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, pentyl propyl ketone, butyl propyl ketone, etc. can be cited.

[0285] As the aromatic compound, for example, benzene, toluene, xylene, etc. can be cited.

[0286] As the aliphatic compound, for example, hexane, heptane, octane, decane, cyclohexane, methylcyclohexane, ethylcyclohexane, cyclooctane, decalin, paraffin, gasoline, naphtha, kerosene, gas oil, etc. can be cited.

[0287] As the nitrile compound, for example, acetonitrile, propionitrile, isobutyronitrile, etc. can be cited.

[0288] As the ester compound, for example, ethyl acetate, butyl acetate, propyl acetate, propyl butyrate, isopropyl butyrate, butyl butyrate, isobutyl butyrate, butyl valerate, ethyl isobutyrate, propyl isobutyrate, isopropyl isobutyrate, isobutyl isobutyrate, propyl pivalate, isopropyl pivalate, butyl pivalate, isobutyl pivalate, etc. can be cited.

[0289] In the present invention, among them, ether compounds, ketone compounds, aromatic compounds, aliphatic compounds, and ester compounds are preferred, and ester compounds, ketone compounds, or ether compounds are more preferred.

[0290] The number of carbon atoms of the compound constituting the dispersion medium is not particularly limited, preferably 2 to 30, more preferably 4 to 20, still more preferably 6 to 15, and particularly preferably 7 to 12.

[0291] From the viewpoint of the dispersion stability of solid particles, for example, the SP value (MPa 1 / 2 ) of the dispersion medium is preferably 9 to 21, more preferably 10 to 20, and still more preferably 11 to 19. The difference (absolute value) between the SP value of the dispersion medium and that of the fluorine-based copolymer is not particularly limited. From the viewpoint of expanding the molecular chain of the fluorine-based copolymer in the dispersion medium to improve its own dispersibility and further improving the dispersion stability of solid particles, it is preferably 8 or less, more preferably 0 to 7.5, and still more preferably 3 to 7.5.

[0292] The SP value of the dispersion medium is the value obtained by converting the SP value calculated by the above-mentioned Hoy method into the unit MPa 1 / 2 When the composition containing an inorganic solid electrolyte contains two or more dispersion media, the SP value of the dispersion medium refers to the SP value of the entire dispersion medium, which is set as the sum of the products of the SP values of the respective dispersion media and their mass fractions. Specifically, except that the SP values of the respective dispersion media are used instead of the SP values of the constituent components, the calculation is performed in the same manner as the calculation method of the SP value of the above polymer.

[0293] The dispersion media having an SP value (MPa 1 / 2 ) of 9 to 21 and their SP values (unit omitted) are shown below.

[0294] 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), ethylcyclohexane (17.1), cyclooctane (18.8)

[0295] The boiling point of the dispersion medium at normal pressure (1 atm) is preferably 50 °C or higher, more preferably 70 °C or higher. The upper limit is preferably 250 °C or lower, and still more preferably 220 °C or lower.

[0296] The composition containing an inorganic solid electrolyte of the present invention only needs to contain at least one dispersion medium, and may contain two or more.

[0297] In the present invention, the content of the dispersion medium in the composition containing an inorganic solid electrolyte is not particularly limited and can be appropriately set. For example, in the composition containing an inorganic solid electrolyte, it is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, and particularly preferably 40 to 60% by mass.

[0298] <Active Substance>

[0299] The composition containing an inorganic solid electrolyte of the present invention can also contain an active material capable of intercalating and deintercalating ions of a metal belonging to Group 1 or Group 2 of the periodic table. As the active material, which will be described below, a positive electrode active material and a negative electrode active material can be mentioned.

[0300] In the present invention, the composition containing an inorganic solid electrolyte containing an active material (positive electrode active material or negative electrode active material) is sometimes referred to as an electrode composition (positive electrode composition or negative electrode composition).

[0301] (Positive electrode active material)

[0302] The positive electrode active material is an active material capable of intercalating and deintercalating ions of a metal belonging to Group 1 or Group 2 of the periodic table, and preferably an active material capable of reversibly intercalating and deintercalating lithium ions. As long as its material is a material having the above characteristics, there is no particular limitation, and it can be a transition metal oxide or organic substance that decomposes the battery, an element such as sulfur that can be complexed with Li, etc.

[0303] Among them, as the positive electrode active material, a transition metal oxide is preferably used, and more preferably a transition metal oxide having a transition metal element M a (one or more elements selected from Co, Ni, Fe, Mn, Cu, and V). Also, an element M b (elements such as elements of Group 1 (Ia) of the metal periodic table other than lithium, elements of Group 2 (IIa) of the metal periodic table, Al, Ga, In, Ge, Sn, Pb, Sb, Bi, Si, P, and B) can be mixed in the transition metal oxide. As the mixing amount, it is preferably 0 to 30 mol% with respect to the amount (100 mol%) of the transition metal element M a . More preferably, it is mixed and synthesized so that the molar ratio of Li / M a becomes 0.3 to 2.2.

[0304] Specific examples of the transition metal oxide can include (MA) a transition metal oxide having a layered rock salt structure, (MB) a transition metal oxide having a spinel structure, (MC) a lithium-containing transition metal phosphate compound, (MD) a lithium-containing transition metal halophosphate compound, and (ME) a lithium-containing transition metal silicate compound, etc.

[0305] Specific examples of the transition metal oxide having a layered rock salt structure of (MA) can include LiCoO2 (lithium cobaltate [LCO]), LiNi2O2 (lithium nickelate), LiNi 0.85 Co 0.10 Al 0.05 O2 (lithium nickel cobalt aluminate [NCA]), LiNi 1 / 3Co 1 / 3 Mn 1 / 3O2 (lithium nickel manganese cobalt oxide [NMC]) and LiNi 0.5 Mn 0.5 O2 (lithium manganese nickel oxide).

[0306] As a specific example of the transition metal oxide (MB) having a spinel structure, LiMn2O4 (LMO), LiCoMnO4, Li2FeMn3O8, Li2CuMn3O8, Li2CrMn3O8, and Li2NiMn3O8 can be cited.

[0307] As the lithium-containing transition metal phosphate compound (MC), for example, olivine-type iron phosphates such as LiFePO4 and Li3Fe2(PO4)3, iron pyrophosphates such as LiFeP2O7, cobalt phosphates such as LiCoPO4, and monoclinic NASICON-type vanadium phosphates such as Li3V2(PO4)3 (lithium vanadium phosphate) can be cited.

[0308] As the lithium-containing transition metal halogenated phosphate compound (MD), for example, iron fluorophosphates such as Li2FePO4F, manganese fluorophosphates such as Li2MnPO4F, and cobalt fluorophosphates such as Li2CoPO4F can be cited.

[0309] As the lithium-containing transition metal silicate compound (ME), for example, Li2FeSiO4, Li2MnSiO4, Li2CoSiO4, etc. can be cited.

[0310] In the present invention, the transition metal oxide (MA) having a layered rock salt structure is preferably used, and LCO or NMC is more preferably used.

[0311] The shape of the positive electrode active material is not particularly limited, and granular shape is preferred. 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 above-mentioned inorganic solid electrolyte. In order to make the positive electrode active material have a specified particle size, a usual pulverizer or classifier is used. For example, a mortar, a ball mill, a sand mill, a vibration ball mill, a satellite ball mill, a planetary ball mill, a rotary air current type jet mill, or a sieve can be appropriately 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. The classification is not particularly limited, and a sieve, an air classifier, etc. can be used for classification. Both dry and wet classification can be used.

[0312] The positive electrode active material obtained by the firing method can also be used after being washed with water, an acidic aqueous solution, an alkaline aqueous solution, and an organic solvent.

[0313] The positive electrode active material can be used alone or in combination of two or more kinds.

[0314] When forming the positive electrode active material layer, the mass (mg) of the positive electrode active material per unit area (cm 2 ) (unit area weight) of the positive electrode active material layer 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 .

[0315] The content of the positive electrode active material in the composition containing the inorganic solid electrolyte is not particularly limited. In 100% by mass of the solid component, it is preferably 10 to 97% by mass, more preferably 30 to 95% by mass, further preferably 40 to 93% by mass, and particularly preferably 50 to 90% by mass.

[0316] (Negative electrode active material)

[0317] The negative electrode active material is an active material capable of inserting and extracting ions of a metal belonging to Group 1 or Group 2 of the periodic table, and preferably an active material capable of reversibly inserting and extracting lithium ions. The material thereof is not particularly limited as long as it is a material having the above characteristics, and examples thereof include carbonaceous materials, metal oxides, metal composite oxides, lithium monomers, lithium alloys, and negative electrode active materials capable of alloying with lithium (capable of alloying). Among them, from the viewpoint of reliability, it is preferable to use a carbonaceous material, a metal composite oxide or a lithium monomer. From the viewpoint of enabling the all-solid-state secondary battery to have a large capacity, it is preferably an active material capable of alloying with lithium. Since the solid particles in the constituent layer formed of the solid electrolyte composition of the present invention are firmly bonded to each other, an active material capable of alloying with lithium can be used as the negative electrode active material. Thereby, the capacity of the all-solid-state secondary battery can be increased and the battery life can be extended.

[0318] The carbonaceous material used as the negative electrode active material refers to a material substantially composed of carbon. For example, carbonaceous materials obtained by firing various synthetic resins such as petroleum pitch, carbon black such as acetylene black (AB), graphite (natural graphite, artificial graphite such as vapor-grown graphite, etc.), and PAN (polyacrylonitrile)-based resins or furfuryl alcohol resins can be listed. Moreover, various carbon fiber types such as PAN-based carbon fibers, cellulose-based carbon fibers, pitch-based carbon fibers, vapor-grown carbon fibers, dehydrated PVA (polyvinyl alcohol)-based carbon fibers, lignin carbon fibers, vitreous carbon fibers, and activated carbon fibers, mesophase microspheres, graphite whiskers, and plate-like graphite can also be listed.

[0319] These carbonaceous materials are classified into poorly graphitizable carbonaceous materials (also known as hard carbon) and graphite-based carbonaceous materials according to the degree of graphitization. Moreover, the carbonaceous material preferably has an interplanar spacing, density, or crystallite size as described in Japanese Patent Laid-Open No. 62-22066, Japanese Patent Laid-Open No. 2-6856, and Japanese Patent Laid-Open No. 3-45473. The carbonaceous material does not have to be a single material, and a mixture of natural graphite and artificial graphite described in Japanese Patent Laid-Open No. 5-90844, graphite having a coating layer described in Japanese Patent Laid-Open No. 6-4516, etc. can also be used.

[0320] As the carbonaceous material, hard carbon or graphite is preferably used, and graphite is more preferably used.

[0321] As the oxide of a metal or semi-metal element applicable as a negative electrode active material, as long as it is an oxide capable of inhaling and releasing lithium, there is no particular limitation, and examples thereof include oxides of metal elements (metal oxides), composite oxides of metal elements, or composite oxides of metal elements and semi-metal elements (collectively referred to as metal composite oxides), and oxides of semi-metal elements (semi-metal oxides). As these oxides, amorphous oxides are preferred, and reaction products of metal elements and elements of Group 16 of the periodic table, i.e., chalcogenides, are further preferably listed. In the present invention, a semi-metal element refers to an element showing intermediate properties between metal elements and non-semi-metal elements, and generally includes six elements: boron, silicon, germanium, arsenic, antimony, and tellurium, and further includes three elements: selenium, polonium, and astatine. Moreover, amorphous means a material having a broad scattering band with a peak in the region of 2θ values of 20° to 40° using X-ray diffraction with CuKα rays, and may also have crystalline diffraction lines. The strongest intensity among the crystalline diffraction lines appearing in the region of 2θ values of 40° to 70° is preferably 100 times or less, more preferably 5 times or less, and particularly preferably does not have crystalline diffraction lines, compared to the intensity of the diffraction line at the peak of the broad scattering band appearing in the region of 2θ values of 20° to 40°.

[0322] Among the compound groups containing the above amorphous oxides and chalcogenides, amorphous oxides of semi-metal elements or the above chalcogenides are even more preferred, and particularly preferred are (composite) oxides or chalcogenides containing a single one or a combination of two or more of elements selected from Group 13 (IIIB) to Group 15 (VB) of the periodic table (e.g., Al, Ga, Si, Sn, Ge, Pb, Sb, and Bi). Specific examples of preferred amorphous oxides and chalcogenides include, for example, Ga2O3, GeO, PbO, PbO2, Pb2O3, Pb2O4, Pb3O4, Sb2O3, Sb2O4, Sb2O8Bi2O3, Sb2O8Si2O3, Sb2O5, Bi2O3, Bi2O4, GeS, PbS, PbS2, Sb2S3, or Sb2S5.

[0323] As negative electrode active materials that can be used in combination with amorphous oxides centered on Sn, Si, and Ge, carbonaceous materials, lithium monomers, lithium alloys, and negative electrode active materials that can alloy with lithium and that can absorb and / or release lithium ions or lithium metal can be preferably cited.

[0324] From the viewpoint of charge-discharge characteristics at high current density, oxides of metal or semi-metal elements, particularly metal (composite) oxides and the above-mentioned chalcogenides preferably contain at least one of titanium and lithium as constituent components. As a metal composite oxide containing lithium (lithium composite metal oxide), for example, a composite oxide of lithium oxide and the above-mentioned metal (composite) oxide or the above-mentioned chalcogenide can be cited, and more specifically, Li2SnO2 can be cited.

[0325] The negative electrode active material, such as a metal oxide, also preferably contains a titanium element (titanium oxide). Specifically, since Li4Ti5O 12 (lithium titanate [LTO]) has a small volume change when absorbing and releasing lithium ions, it is excellent in rapid charge and discharge characteristics, suppresses the deterioration of the electrode, and is preferable in that it can improve the life of the lithium ion secondary battery in two respects.

[0326] The lithium alloy as the negative electrode active material is not particularly limited as long as it is an alloy generally used as the negative electrode active material of a secondary battery. For example, a lithium-aluminum alloy can be cited.

[0327] The negative electrode active material that can alloy with lithium is not particularly limited as long as it is an active material generally used as the negative electrode active material of a secondary battery. Since this kind of active material has a large expansion and contraction due to charge and discharge of the all-solid-state secondary battery and accelerates the deterioration of the cycle characteristics, the composition containing the inorganic solid electrolyte of the present invention contains the above-mentioned fluorine-containing binder, and thus can suppress the deterioration of the cycle characteristics. As such an active material, (negative electrode) active materials (alloys, etc.) having a silicon element or a tin element, various metals such as Al and In can be cited, and a negative electrode active material having a silicon element (a silicon element-containing active material) capable of achieving a higher battery capacity is preferable, and a silicon element-containing active material having a silicon element content of 50 mol% or more of all constituent elements is more preferable.

[0328] Generally, a negative electrode containing these negative electrode active materials (for example, a Si negative electrode containing a silicon element-containing active material, a Sn negative electrode containing an active material having a tin element, etc.) can absorb more Li ions than a carbon negative electrode (graphite, acetylene black, etc.). That is, the amount of Li ions occluded per unit mass increases. Therefore, the battery capacity (energy density) can be increased. As a result, it has the advantage of being able to extend the battery driving time.

[0329] As the active material containing a silicon element, for example, silicon materials such as Si and SiOx (0 < x ≤ 1), silicon-containing alloys containing titanium, vanadium, chromium, manganese, nickel, copper, lanthanum, etc. (for example, LaSi2, VSi2, La-Si, Gd-Si, Ni-Si) or organized active materials (for example, LaSi2 / Si), and active materials containing silicon and tin elements such as SnSiO3 and SnSiS3 can be cited. In addition, SiOx can be used as the negative electrode active material (semi-metal oxide) itself, and Si is generated by the operation of the all-solid-state secondary battery, so it can be used as the negative electrode active material (its precursor material) capable of alloying with lithium.

[0330] As the negative electrode active material containing a tin element, for example, those containing Sn, SnO, SnO2, SnS, SnS2, and the above-mentioned active materials containing silicon and tin elements can be cited. And composite oxides with lithium oxide, such as Li2SnO2, can also be cited.

[0331] In the present invention, the above-mentioned negative electrode active material can be used without particular limitation, but from the viewpoint of battery capacity, as the negative electrode active material, a mode that can alloy with lithium is preferred, among which, the above-mentioned silicon material or silicon-containing alloy (alloy containing a silicon element) is more preferred, and silicon (Si) or a silicon-containing alloy is further preferred.

[0332] As a measurement method, it can be analyzed by inductively coupled plasma (ICP) emission spectrometry, and as a simple method, the chemical formula of the compound obtained by the above-mentioned firing method can be calculated from the mass difference of the powder before and after firing.

[0333] The shape of the negative electrode active material is not particularly limited, and a granular shape is preferred. The volume average particle diameter of the negative electrode active material is not particularly limited, and is preferably 0.1 to 60 μm. The volume average particle diameter of the negative electrode active material particles can be measured in the same manner as the particle diameter of the above-mentioned inorganic solid electrolyte. In order to set it to a specified particle diameter, a usual pulverizer or classifier is used in the same manner as the positive electrode active material.

[0334] The above-mentioned negative electrode active material can be used alone or in combination of two or more.

[0335] When forming the negative electrode active material layer, the mass (mg) (weight per unit area) of the negative electrode active material per unit area (cm 2 ) 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 .

[0336] The content of the negative electrode active material in the composition containing the inorganic solid electrolyte is not particularly limited, and in 100% by mass of the solid component, it is preferably 10 to 90% by mass, more preferably 20 to 85% by mass, still more preferably 30 to 80% by mass, and further preferably 40 to 75% by mass.

[0337] In the present invention, when forming the negative electrode active material layer by charging the secondary battery, instead of the above-mentioned negative electrode active material, ions belonging to metals in Group 1 or Group 2 of the periodic table generated in the all-solid-state secondary battery can be used. By bonding the ions with electrons to precipitate as a metal, the negative electrode active material layer can be formed.

[0338] (Coating of the active material)

[0339] The surfaces of the positive electrode active material and the negative electrode active material can also be surface-coated with different metal oxides. As the surface coating agent, metal oxides containing Ti, Nb, Ta, W, Zr, Al, Si, or Li can be cited, etc. Specifically, spinel titanate, tantalum-based oxides, niobium-based oxides, lithium niobate-based 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.

[0340] Moreover, the surface of the electrode containing the positive electrode active material or the negative electrode active material can be surface-treated with sulfur or phosphorus.

[0341] Furthermore, the surfaces of the particles of the positive electrode active material or the negative electrode active material can be surface-treated with actinic rays or active gases (such as plasma) before and after the above surface coating.

[0342] <Conductive aid>

[0343] The composition containing the inorganic solid electrolyte of the present invention preferably contains a conductive aid. For example, it is preferred to use a conductive aid in combination with an active material containing a silicon atom as the negative electrode active material.

[0344] As the conductive additive, there is no particular limitation, and conductive additives known generally as conductive additives can be used. For example, it can be graphite-based materials such as natural graphite and artificial graphite as electron conductive materials, carbon black-based materials such as acetylene black, Ketjenblack, and furnace black, amorphous carbon such as needle coke, carbon fiber-based materials such as vapor-grown carbon fiber or carbon nanotube, carbonaceous materials such as graphene or fullerene, metal powders and metal fibers such as copper and nickel, and conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene, and polyphenylene derivatives.

[0345] In the present invention, in the case of using the active material and the conductive additive in combination, among the above conductive additives, when the battery is charged and discharged, no ions (preferably Li ions) of metals belonging to Group 1 or Group 2 of the periodic table are inserted and extracted, and the conductive additive that does not function as an active material. Therefore, among the conductive additives, those that can function as an active material in the active material layer when the battery is charged and discharged are classified as active materials rather than conductive additives. Whether it functions as an active material when the battery is charged and discharged is determined by the combination with the active material, rather than being determined unconditionally.

[0346] The conductive additive may contain one kind or may contain two or more kinds.

[0347] The shape of the conductive additive is not particularly limited, and preferably granular.

[0348] When the composition containing the inorganic solid electrolyte of the present invention contains a conductive additive, the content of the conductive additive in the composition containing the inorganic solid electrolyte is preferably 0 to 10% by mass in 100% by mass of the solid component.

[0349] <Lithium salt>

[0350] The composition containing the inorganic solid electrolyte of the present invention preferably further contains a lithium salt (supporting electrolyte).

[0351] As the lithium salt, the lithium salt usually used for such products is preferred, and there is no particular limitation. For example, the lithium salts described in paragraphs 0082 to 0085 of JP-A-2015-088486 are preferred.

[0352] When the composition containing the inorganic solid electrolyte of the present invention contains a lithium salt, the content of the lithium salt is preferably 0.1 part by mass or more, more preferably 5 parts by mass or more, relative to 100 parts by mass of the solid electrolyte. As the upper limit, it is preferably 50 parts by mass or less, more preferably 20 parts by mass or less.

[0353] <Dispersant>

[0354] In the composition containing an inorganic solid electrolyte of the present invention, the above polymer binder also functions as a dispersant. Therefore, a dispersant other than the polymer binder may not be included, or a dispersant may be included. As the dispersant, a dispersant commonly used in all-solid-state secondary batteries can be appropriately selected and used. Generally, a compound required in particle adsorption, steric exclusion, and / or electrostatic exclusion is appropriately used.

[0355] <Other Additives>

[0356] The composition containing an inorganic solid electrolyte of the present invention can appropriately contain an ionic liquid, a thickener, a crosslinking agent (such as a substance that undergoes a crosslinking reaction through free radical polymerization, condensation polymerization, or ring-opening polymerization), a polymerization initiator (such as a substance that generates an acid or a free radical through heat or light), an antifoaming agent, a homogenizing agent, a dehydrating agent, an antioxidant, etc. as other components other than the above components. The ionic liquid is a liquid contained to further improve the ionic conductivity, and a known liquid can be used without particular limitation. In addition, a binder commonly used, etc., can be contained in a polymer other than the polymer forming the above polymer binder.

[0357] (Preparation of the Composition Containing an Inorganic Solid Electrolyte)

[0358] The composition containing an inorganic solid electrolyte of the present invention can be prepared, for example, by mixing an inorganic solid electrolyte, the above fluorine-containing binder as a polymer binder, the above dispersion medium, preferably a granular binder, a chain polymerization polymer binder, a conductive aid, and an appropriate lithium salt, and any other components in various commonly used mixers, as a mixture, preferably as a slurry. In the case of an electrode composition, an active material is further mixed.

[0359] The mixing method is not particularly limited, and it can be mixed at once or sequentially. The mixing environment is not particularly limited, and examples include under dry air or under an inert gas.

[0360] [Sheet for All-Solid-State Secondary Battery]

[0361] The sheet for an all-solid-state secondary battery of the present invention is a sheet-shaped molded body capable of forming a constituent layer of an all-solid-state secondary battery, and includes various forms 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 an electrode or a laminate of an electrode and a solid electrolyte layer (an 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.

[0362] The solid electrolyte sheet for all-solid-state secondary batteries of the present invention only needs to be a sheet having a solid electrolyte layer, and can be a sheet with a solid electrolyte layer formed on a substrate, or a sheet formed only of a solid electrolyte layer without a substrate. The solid electrolyte sheet for all-solid-state secondary batteries may have other layers in addition to the solid electrolyte layer. Examples of other layers include a protective layer (release sheet), a current collector, a coating layer, etc.

[0363] As the solid electrolyte sheet for all-solid-state secondary batteries of the present invention, for example, a sheet having, in this order on a substrate, a layer composed of the composition containing an inorganic solid electrolyte of the present invention, a normal solid electrolyte layer, and a protective layer can be cited. The solid electrolyte layer of the solid electrolyte sheet for all-solid-state secondary batteries is preferably formed of the composition containing an inorganic solid electrolyte of the present invention. The content of each component in the solid electrolyte layer is not particularly limited, and preferably has the same meaning as the content of each component in the solid component of the composition containing an inorganic solid electrolyte of the present invention. The layer thickness of each layer constituting the solid electrolyte sheet for all-solid-state secondary batteries is the same as the layer thickness of each layer described in the all-solid-state secondary battery described later.

[0364] As the substrate, as long as it is a substrate capable of supporting the solid electrolyte layer, there is no particular limitation, and examples include sheet materials (plate-like bodies) such as the materials described in the current collector described later, organic materials, and inorganic materials. As organic materials, various polymers can be cited, and specifically, polyethylene terephthalate, polypropylene, polyethylene, and cellulose can be cited. As inorganic materials, for example, glass and ceramics can be cited.

[0365] The electrode sheet for all-solid-state secondary batteries of the present invention (also simply referred to as "electrode sheet") only needs to be an electrode sheet having an active material layer, and can be a sheet with an active material layer formed on a substrate (current collector), or a sheet formed only of an active material layer without a substrate. This electrode sheet is usually a sheet having a current collector and an active material layer, but also includes forms having, in this order, a current collector, an active material layer, and a solid electrolyte layer, and forms having, in this order, a current collector, an active material layer, a solid electrolyte layer, and an active material layer. The solid electrolyte layer and the active material layer of the electrode sheet are preferably formed of the composition containing an inorganic solid electrolyte of the present invention. The content of each component in the solid electrolyte layer or the active material layer is not particularly limited, and preferably has the same meaning as the content of each component in the solid component of the composition containing an inorganic solid electrolyte of the present invention (electrode composition). The layer thickness of each layer constituting the electrode sheet of the present invention is the same as the layer thickness of each layer described in the all-solid-state secondary battery described later. The electrode sheet of the present invention may have the above-mentioned other layers.

[0366] In the sheet for all-solid-state secondary battery of the present invention, at least one of the solid electrolyte layer and the active material layer is formed of the composition containing an inorganic solid electrolyte of the present invention, and has a constituent layer with a flat surface and low resistance. Therefore, the sheet for all-solid-state secondary battery of the present invention is used as a constituent layer of an all-solid-state secondary battery, whereby excellent cycle characteristics and low resistance of the all-solid-state secondary battery can be achieved. In particular, in the electrode sheet for all-solid-state secondary battery and the all-solid-state secondary battery in which the active material layer is formed of the composition containing an inorganic solid electrolyte of the present invention, the active material layer and the current collector exhibit strong adhesion, and further improvement in cycle characteristics can be achieved. Therefore, the sheet for all-solid-state secondary battery of the present invention is suitable as a sheet capable of forming a constituent layer of an all-solid-state secondary battery.

[0367] [Method for manufacturing a sheet for all-solid-state secondary battery]

[0368] The method for manufacturing the sheet for all-solid-state secondary battery of the present invention is not particularly limited, and can be manufactured by forming the above-mentioned respective layers using the composition containing an inorganic solid electrolyte of the present invention. For example, a method of forming a layer (coating and drying layer) composed of a composition containing an inorganic solid electrolyte by film-forming (coating and drying) on a substrate or a current collector (it may be via another layer) is preferably cited. Thereby, a sheet for all-solid-state secondary battery having a substrate or a current collector and a coating and drying layer can be produced. In particular, when the sheet for all-solid-state secondary battery is produced by film-forming the composition containing an inorganic solid electrolyte of the present invention on a current collector, the adhesion between the current collector and the active material layer can be made strong. Here, the coating and drying layer means a layer formed by coating the composition containing an inorganic solid electrolyte of the present invention and drying the dispersion medium (that is, a layer formed using the composition containing an inorganic solid electrolyte of the present invention and composed of a composition in which the dispersion medium is removed from the composition containing an inorganic solid electrolyte of the present invention). As long as the active material layer and the coating and drying layer are within the range not impairing the effects of the present invention, the dispersion medium may remain, and as the remaining amount, for example, it can be set to 3% by mass or less in each layer.

[0369] In the method for manufacturing the sheet for all-solid-state secondary battery of the present invention, each process such as coating and drying will be described in the method for manufacturing the following all-solid-state secondary battery.

[0370] In the method for manufacturing the sheet for all-solid-state secondary battery of the present invention, the coating and drying layer obtained in the above manner can also be pressed. Regarding the pressing conditions and the like, they will be described in the method for manufacturing the all-solid-state secondary battery described later.

[0371] Moreover, in the method for manufacturing the sheet for all-solid-state secondary battery of the present invention, the substrate, the protective layer (especially the release sheet), etc. can also be peeled off.

[0372] [All-solid-state secondary battery]

[0373] The all-solid-state secondary battery of the present invention has a positive electrode active material layer, a negative electrode active material layer opposed 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 positive electrode active material layer is preferably formed on a positive electrode current collector and constitutes the positive electrode. The negative electrode active material layer is preferably formed on a negative electrode current collector and constitutes the negative electrode.

[0374] At least one of the negative electrode active material layer, the positive electrode active material layer, and the solid electrolyte layer is preferably formed of the composition containing an inorganic solid electrolyte of the present invention, and it is also one of the preferred modes that all layers are formed of the composition containing an inorganic solid electrolyte of the present invention. Regarding the types of components contained and their content ratios, the active material layer or the solid electrolyte layer formed of the composition containing an inorganic solid electrolyte of the present invention is preferably the same as that in the solid components of the composition containing an inorganic solid electrolyte of the present invention. In addition, when the active material layer or the solid electrolyte layer is not formed of the composition containing an inorganic solid electrolyte of the present invention, known materials can be used.

[0375] The respective thicknesses of the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer are not particularly limited. Considering the size of a general all-solid-state secondary battery, the thickness of each layer is preferably 10 to 1,000 μm, more preferably 20 μm or more and less than 500 μm. In the all-solid-state secondary battery of the present invention, 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 more and less than 500 μm.

[0376] The positive electrode active material layer and the negative electrode active material layer can each have a current collector on the side opposite to the solid electrolyte layer.

[0377] <Case>

[0378] The all-solid-state secondary battery of the present invention can be used as an all-solid-state secondary battery in the above-described structure according to the application, but in order to make it in the form of a dry battery, it is preferably further enclosed in a suitable case for use. The case can be a metallic case or a resin (plastic) case. In the case of using a metallic case, for example, a case made of aluminum alloy or stainless steel can be cited. It is preferred that the metallic case is divided into a positive electrode side case and a negative electrode side case and is electrically connected to the positive electrode current collector and the negative electrode current collector, respectively. It is preferred that the positive electrode side case and the negative electrode side case are joined with a short-circuit prevention gasket therebetween and integrated.

[0379] Hereinafter, with reference to Figure 1 , the all-solid-state secondary battery according to the preferred embodiment of the present invention will be described, but the present invention is not limited thereto.

[0380] Figure 1This is a cross-sectional view schematically showing the all-solid-state secondary battery (lithium-ion secondary battery) according to the preferred embodiment of the present invention. When viewed from the negative electrode side, the all-solid-state secondary battery 10 of the present embodiment sequentially includes a negative electrode current collector 1, a negative electrode active material layer 2, a solid electrolyte layer 3, a positive electrode active material layer 4, and a positive electrode current collector 5. 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 accumulated therein together with lithium ions (Li + ). On the other hand, during discharging, the lithium ions (Li + ) accumulated in the negative electrode return to the positive electrode side and supply electrons to the working part 6. In the illustrated example, a light bulb is used as a model for the working part 6, and the light bulb is lit by discharging.

[0381] When the all-solid-state secondary battery having the Figure 1 shown layer structure is placed in a 2032-type button battery case, the all-solid-state secondary battery is sometimes also referred to as a laminate for all-solid-state secondary batteries, and the battery produced by placing the laminate for all-solid-state secondary batteries in a 2032-type button battery case is referred to as an all-solid-state secondary battery.

[0382] (Positive electrode active material layer, solid electrolyte layer, negative electrode active material layer)

[0383] In the all-solid-state secondary battery 10, the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer are all formed of the composition containing an inorganic solid electrolyte of the present invention. The all-solid-state secondary battery 10 exhibits excellent battery performance. The inorganic solid electrolytes and polymer binders (fluorine-containing binders) contained in the positive electrode active material layer 4, the solid electrolyte layer 3, and the negative electrode active material layer 2 may be of the same type or different types, respectively.

[0384] In the present invention, either one or both of the positive electrode active material layer and the negative electrode active material layer are simply referred to as an active material layer or an electrode active material layer. And either one or both of the positive electrode active material and the negative electrode active material are simply referred to as an active material or an electrode active material.

[0385] In the present invention, when forming a constituent layer from the composition containing an inorganic solid electrolyte of the present invention, an all-solid-state secondary battery with excellent cycle characteristics and an all-solid-state secondary battery with low resistance can be realized.

[0386] 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 stacking or molding lithium metal powder, a lithium foil, and a lithium vapor deposition film. The thickness of the lithium metal layer has nothing to do with the thickness of the negative electrode active material layer described above. For example, it can be set to 1 to 500 μm.

[0387] The positive current collector 5 and the negative current collector 1 are preferably electronic conductors.

[0388] In the present invention, either one of the positive current collector and the negative current collector, or both of them together, may sometimes be simply referred to as the current collector.

[0389] As the material for forming the positive current collector, in addition to aluminum, aluminum alloy, stainless steel, nickel, titanium, etc., a material (a material having a film formed) in which carbon, nickel, titanium, or silver is surface-treated on aluminum or stainless steel is preferred, and among them, aluminum and aluminum alloy are more preferred.

[0390] As the material for forming the negative current collector, in addition to aluminum, copper, copper alloy, stainless steel, nickel, titanium, etc., a material in which carbon, nickel, titanium, or silver is surface-treated on aluminum, copper, copper alloy, or stainless steel is preferred, and aluminum, copper, copper alloy, and stainless steel are more preferred.

[0391] The shape of the current collector generally adopts a film-like shape, but a net-like material, a perforated body, a slat body, a porous body, a foamed body, a formed body of a fiber group, etc. can also be used.

[0392] The thickness of the current collector is not particularly limited, and is preferably 1 to 500 μm. Further, it is also preferred to provide irregularities on the surface of the current collector by surface treatment.

[0393] In the all-solid-state secondary battery 10 described above, the positive electrode active material layer can also be a layer formed of a known layer-forming material.

[0394] In the present invention, a functional layer, component, etc. can be appropriately inserted or disposed between or outside each of the negative current collector, the negative electrode active material layer, the solid electrolyte layer, the positive electrode active material layer, and the positive current collector. And each layer can be configured as a single layer or as multiple layers.

[0395] [Manufacture of All-Solid-State Secondary Battery]

[0396] The all-solid-state secondary battery can be manufactured by a conventional method. Specifically, the all-solid-state secondary battery can be manufactured by forming the above-mentioned respective layers using the composition containing an inorganic solid electrolyte of the present invention, etc. Hereinafter, a detailed description will be given.

[0397] The all-solid-state secondary battery of the present invention can be manufactured by a method (a method for manufacturing a sheet for an all-solid-state secondary battery of the present invention) including a step of forming a coating film (film formation) by appropriately coating the composition containing an inorganic solid electrolyte of the present invention on a substrate (for example, a metal foil serving as a current collector).

[0398] For example, a positive electrode active material layer is formed by coating a composition containing an inorganic solid electrolyte and a positive electrode active material (positive electrode composition) on a metal foil serving as a positive electrode current collector to produce a positive electrode sheet for an all-solid-state secondary battery. Subsequently, a solid electrolyte layer is formed by coating a composition containing an inorganic solid electrolyte for forming the solid electrolyte layer on the positive electrode active material layer. Further, a negative electrode active material layer is formed by coating a composition containing an inorganic solid electrolyte and a negative electrode active material (negative electrode composition) on the solid electrolyte layer. By overlapping a negative electrode current collector (metal foil) on the negative electrode active material layer, an all-solid-state secondary battery having a structure in which the 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 case to form a desired all-solid-state secondary battery.

[0399] Moreover, conversely to the formation method of each layer, an all-solid-state secondary battery can also 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 overlapping a positive electrode current collector.

[0400] 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. And a negative electrode active material layer is formed by coating a composition containing an inorganic solid electrolyte and a negative electrode active material (negative electrode composition) on a metal foil serving as a negative electrode current collector to produce a negative electrode sheet for an all-solid-state secondary battery. Subsequently, a solid electrolyte layer is formed on the active material layer of any of these sheets as described above. Further, the other of the positive electrode sheet for an all-solid-state secondary battery and the negative electrode sheet for an all-solid-state secondary battery is laminated 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.

[0401] Moreover, 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 produced as described above. In addition, a solid electrolyte sheet for an all-solid-state secondary battery composed of a solid electrolyte layer is produced by coating a composition containing an inorganic solid electrolyte on a substrate. Further, they are laminated in such a form that the solid electrolyte layer peeled 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.

[0402] In addition, as described above, a positive electrode sheet for an all-solid-state secondary battery, a negative electrode sheet for an all-solid-state secondary battery, and a solid electrolyte sheet for an all-solid-state secondary battery are produced. Next, the positive electrode sheet for an all-solid-state secondary battery or the negative electrode sheet for an all-solid-state secondary battery and the solid electrolyte sheet for an all-solid-state secondary battery are overlapped and pressed in a state where the positive electrode active material layer or the negative electrode active material layer is in contact with the solid electrolyte layer. In this way, the solid electrolyte layer is transferred to the positive electrode sheet for an all-solid-state secondary battery or the negative electrode sheet for an all-solid-state secondary battery. Then, the solid electrolyte layer obtained by peeling the substrate of the solid electrolyte sheet for an all-solid-state secondary battery and the negative electrode sheet for an all-solid-state secondary battery or the positive electrode sheet for an all-solid-state secondary battery (in a state where the negative electrode active material layer or the positive electrode active material layer is in contact with the solid electrolyte layer) are overlapped and pressed. In this way, an all-solid-state secondary battery can be manufactured. The pressing method, pressing conditions, etc. in this method are not particularly limited, and the methods and pressing conditions, etc. described in the pressing of the composition to be coated described later can be applied.

[0403] The solid electrolyte layer, etc. is formed, for example, by pressing and molding a composition containing an inorganic solid electrolyte, etc. on a substrate or an active material layer under the pressing conditions described later.

[0404] In the above manufacturing method, the composition containing an inorganic solid electrolyte of the present invention can be used for any one of the positive electrode composition, the composition containing an inorganic solid electrolyte, and the negative electrode composition. It is preferable to use the composition containing an inorganic solid electrolyte of the present invention for the composition containing an inorganic solid electrolyte, and the composition containing an inorganic solid electrolyte of the present invention can also be used for any composition.

[0405] When the solid electrolyte layer or the active material layer is formed from a composition other than the solid electrolyte composition of the present invention, examples of its material include commonly used compositions, etc. And when manufacturing an all-solid-state secondary battery, if the negative electrode active material layer is not formed, ions of a metal belonging to Group 1 or Group 2 of the periodic table that are accumulated in the negative electrode current collector through the initialization or charging during use described later are combined with electrons and deposited as a metal on the negative electrode current collector, etc., and thus the negative electrode active material layer can also be formed.

[0406] The solid electrolyte layer, etc. can also be formed, for example, by pressing and molding a solid electrolyte composition, etc. on a substrate or an active material layer under the pressing conditions described later, and a sheet molded body of a solid electrolyte or an active material can also be used.

[0407] <Formation (film formation) of each layer>

[0408] The coating method of the composition containing an inorganic solid electrolyte is not particularly limited and can be appropriately selected. For example, coating (preferably wet coating), spraying, spin coating, dip coating, slot coating, stripe coating, bar coating can be cited.

[0409] At this time, the composition containing the inorganic solid electrolyte can be dried after separate coating or after multi-layer coating. The drying temperature is not particularly limited. The lower limit is preferably 30°C or higher, more preferably 60°C or higher, and further preferably 80°C or higher. The upper limit is preferably 300°C or lower, more preferably 250°C or lower, and further preferably 200°C or lower. By heating within such a temperature range, the dispersion medium can be removed to obtain a solid state (coating drying layer). Moreover, the temperature is not too high and the components of the all-solid-state secondary battery are not damaged, so it is preferred. Thus, in the all-solid-state secondary battery, excellent overall performance is exhibited and good adhesiveness and good ion conductivity without pressure can be obtained.

[0410] As described above, when coating and drying the composition containing the inorganic solid electrolyte of the present invention, deviation in the contact state can be suppressed and solid particles can be bonded, and a coating drying layer with a flat surface can be formed.

[0411] It is preferred to press each layer or the all-solid-state secondary battery after overlapping the constituent layers or manufacturing the all-solid-state secondary battery after coating the composition containing the inorganic solid electrolyte. Examples of the pressing method include a hydraulic cylinder stamping machine. The pressing force is not particularly limited, and generally, it is preferably in the range of 5 to 1500 MPa.

[0412] Moreover, the coated composition containing the inorganic solid electrolyte can be heated while being pressed. The heating temperature is not particularly limited, and generally, it is in the range of 30 to 300°C. Stamping can also be performed at a temperature higher than the glass transition temperature of the inorganic solid electrolyte. Additionally, stamping can also be performed at a temperature higher than the glass transition temperature of the polymer contained in the polymer binder. However, generally, it is a temperature not exceeding the melting point of the polymer.

[0413] Pressing can be performed in a state where the coating solvent or dispersion medium has been pre-dried, or can also be performed in a state where the solvent or dispersion medium remains.

[0414] In addition, each composition can be coated simultaneously, or coating, drying, and stamping can be performed simultaneously and / or stepwise. After coating on their respective substrates, they can be laminated by transfer.

[0415] As the manufacturing process, for example, the environment during heating or pressing is not particularly limited, and it can be any environment such as under atmospheric pressure, under dry air (dew point -20°C or lower), in an inert gas (for example, in argon, in helium, in nitrogen), etc.

[0416] The stamping time can apply high pressure for a short time (e.g., within a few hours) or medium pressure for a long time (more than 1 day). In cases other than the sheet for all-solid-state secondary batteries, for example, in the case of all-solid-state secondary batteries, the restraint tools (such as screw fastening pressure) of the all-solid-state secondary batteries can be used to continuously apply medium pressure.

[0417] Relative to the pressed part such as the sheet surface, the stamping pressure can be a uniform pressure or different pressures.

[0418] The stamping pressure can be changed according to the area or film thickness of the pressed part. Also, the same part can be changed in stages with different pressures.

[0419] The stamping surface can be smooth or rough.

[0420] <Initialization>

[0421] The all-solid-state secondary battery manufactured as described above is preferably initialized after manufacture or before use. The initialization is not particularly limited. For example, initial charging and discharging can be performed in a state where the stamping pressure is increased, and then the pressure is released until the general use pressure of the all-solid-state secondary battery is reached.

[0422] [Uses of All-Solid-State Secondary Batteries]

[0423] The all-solid-state secondary battery of the present invention can be applied to various uses. The application method is not particularly limited. For example, in the case of being mounted on an electronic device, examples include laptop computers, pen input computers, mobile computers, e-book readers, mobile phones, cordless phone handsets, pagers, handheld terminals, portable fax machines, portable copiers, portable printers, stereo headphones, video cameras, liquid crystal TVs, handheld vacuum cleaners, portable CDs, floppy disks, electric shavers, transceivers, electronic notebooks, calculators, memory cards, portable tape recorders, radios, backup power supplies, etc. As other civilian products, examples include automobiles, electric vehicles, motors, lighting fixtures, toys, game consoles, load regulators, clocks, flashlights, cameras, and medical devices (such as pacemakers, hearing aids, and shoulder massagers, etc.). Moreover, it can be used as various military and aviation products. And it can also be combined with solar cells.

[0424] Examples

[0425] Hereinafter, the present invention will be further described in detail based on examples, but the present invention is not construed as being limited thereto. In the following examples, "parts" and "%" representing the composition are based on mass unless otherwise specified. In the present invention, "room temperature" means 25°C.

[0426] 1. Synthesis of Fluorine-based Copolymer and Preparation of Fluorine-based Copolymer Solution

[0427] [Synthesis Example 1: Synthesis of Fluorine-based Copolymer S-1 and Preparation of Adhesive Solution S-1]

[0428] A fluorine-based copolymer S-1 was synthesized, and an adhesive solution S-1 (concentration: 10% by mass) composed of this fluorine-based copolymer was prepared.

[0429] Specifically, 200 parts by mass of ion-exchanged water, 102 parts by mass of vinylidene fluoride, 98 parts by mass of hexafluoropropylene were added to an autoclave, and 2 parts by mass of diisopropyl peroxydicarbonate was added, followed by stirring at 30°C for 24 hours. After the polymerization was completed, the precipitate was filtered and dried at 100°C for 10 hours to obtain a polymer (adhesive) S-1. The obtained polymer was a random copolymer with a weight-average molecular weight of 249,000. The obtained polymer was dissolved in butyl butyrate to obtain an adhesive solution.

[0430] [Synthesis Examples 2 to 16: Synthesis of Fluorine-based Copolymers S-2 to S-15 and S-26 and Preparation of Adhesive Solutions S-2 to S-15 and S-26]

[0431] In Synthesis Example 1, compounds (polymerizable compounds having functional groups) having components with VDF, HFP and functional groups were introduced so that the fluorine-based copolymers S-2 to S-15 and S-26 had the compositions (types and contents of components) shown in Table 1. Except for this, polymers S-2 to S-15 and S-26 were synthesized in the same manner as in Synthesis Example 1, and adhesive solutions S-2 to S-15 and adhesive dispersions S-26 (both with a concentration of 10% by mass) composed of the respective fluorine-based copolymers were obtained.

[0432] In addition, in the synthesis conditions of polymer S-4, the amount of diisopropyl peroxydicarbonate was changed to 0.2 parts by mass to synthesize polymer S-26. The average particle diameter of the polymer adhesive composed of polymer S-26 in the prepared adhesive dispersion S-26 was 890 nm.

[0433] [Synthesis Examples 17 to 19: Synthesis of Fluorine-based Copolymers S-16, CS-1 and CS-2 and Preparation of Adhesive Solutions S-16, CS-1 and CS-2]

[0434] In Synthesis Example 1, VDF, HFP, and tetrafluoroethylene (TFE) were used to make the fluorine-based copolymers S-16, CS-1, and CS-2 have the compositions (types and contents of constituent components) shown in Table 1. Other than that, polymers S-16, CS-1, and CS-2 were synthesized in the same manner as in Synthesis Example 1, and adhesive solutions S-16, CS-1, and CS-2 (all at a concentration of 10% by mass) composed of the respective fluorine-based copolymers were obtained.

[0435] [Synthesis Examples 20 and 21: Synthesis of Fluorine-Based Copolymers S-17 and S-25 and Preparation of Adhesive Solutions S-17 and S-25]

[0436] In Synthesis Example 1, VDF, HFP, and tetrafluoroethylene were used such that the fluorine-based copolymers S-17 and S-25 had the compositions (types and contents of constituent components) shown in Table 1, and the amount of polymerization initiator was adjusted. Other than that, polymers S-17 and S-25 were synthesized in the same manner as in Synthesis Example 1, and adhesive solutions S-17 and S-25 (all at a concentration of 10% by mass) composed of the respective fluorine-based copolymers were obtained.

[0437] The following synthesized fluorine-based copolymers S-18 to S-24 are shown. The numbers written at the lower right of each constituent component represent the content (mol%) of each constituent component in the fluorine-based copolymer. The * of the constituent component indicates that each structural substitution position is a mixture of positional isomers.

[0438] [Chemical Formula 6]

[0439]

[0440] [Synthesis Example 22: Synthesis of Fluorine-Based Copolymer S-18 and Preparation of Adhesive Solution S-18]

[0441] The fluorine-based copolymer S-18 was synthesized, and an adhesive solution S-18 (concentration: 10% by mass) composed of the fluorine-based copolymer was prepared.

[0442] Specifically, 180 parts by mass of tetrahydrofuran and 20 parts by mass of the fluorine-based copolymer S-17 synthesized in Synthesis Example 20 were added to a 500 mL three-necked flask equipped with a reflux condenser. Further, 0.28 g of lithium hydroxide and 40 g of methanol were added, and the mixture was stirred at 60 °C for 6 hours. Then, it was dropped into water, the precipitate was filtered, and vacuum drying was performed to obtain a polymer precursor (S-18).

[0443] Next, 90 parts by mass of N-methylpyrrolidone and 10 parts by mass of the above polymer precursor (S-18) were added to a 300 mL three-necked flask equipped with a reflux condenser and a gas inlet plug and dissolved. Then, after introducing nitrogen at a flow rate of 200 mL / min for 10 minutes, the temperature was raised to 75 °C, 12 parts by mass of dodecanethiol and 0.6 parts by mass of azobisisobutyronitrile (manufactured by FUJIFILM Wako Pure Chemical Corporation) were added, and stirring was continued for 5 hours. Then, it was dropped into hexane, and a fluorine-based copolymer S-18 was obtained as a precipitate. After performing reduced-pressure drying at 60 °C for 5 hours, it was dissolved in an arbitrary solvent again. The obtained fluorine-based copolymer was dissolved in butyl butyrate to obtain an adhesive solution S-18 (concentration: 10% by mass).

[0444] [Synthesis Example 23: Synthesis of Fluorine-Based Copolymer S-19 and Preparation of Adhesive Solution S-19]

[0445] A fluorine-based copolymer S-19 was synthesized, and an adhesive solution S-19 (concentration: 10% by mass) composed of the fluorine-based copolymer was prepared.

[0446] Specifically, 180 parts by mass of tetrahydrofuran and 20 parts by mass of the fluorine-based copolymer S-17 synthesized in Synthesis Example 20 were added to a 500 mL three-necked flask equipped with a reflux condenser, 0.17 g of lithium hydroxide and 40 g of methanol were further added, and stirring was performed at 60 °C for 6 hours. Then, it was dropped into water, the precipitate was filtered, and vacuum drying was performed to obtain a polymer precursor (S-19).

[0447] Next, 90 parts by mass of N-methylpyrrolidone and 10 parts by mass of the above polymer precursor (S-19) were added to a 300 mL three-necked flask equipped with a reflux condenser and a gas inlet plug and dissolved. Then, after introducing nitrogen at a flow rate of 200 mL / min for 10 minutes, the temperature was raised to 75 °C, 8 parts by mass of 6-mercapto-1-hexanol and 0.6 parts by mass of azobisisobutyronitrile (manufactured by FUJIFILM Wako Pure Chemical Corporation) were added, and stirring was continued for 5 hours. Then, it was dropped into hexane, and a fluorine-based copolymer S-19 was obtained as a precipitate. After performing reduced-pressure drying at 60 °C for 5 hours, it was dissolved in an arbitrary solvent again. The obtained fluorine-based copolymer was dissolved in butyl butyrate to obtain an adhesive solution S-19 (concentration: 10% by mass).

[0448] [Synthesis Example 24: Synthesis of Fluorine-Based Copolymer S-20 and Preparation of Adhesive Solution S-20]

[0449] A fluorine-based copolymer S-20 was synthesized, and an adhesive solution S-20 (concentration: 10% by mass) composed of the fluorine-based copolymer was prepared.

[0450] Specifically, 900 parts by mass of tetrahydrofuran and 100 parts by mass of the fluorine-based copolymer S-17 synthesized in Synthesis Example 20 were added to a 2 L three-necked flask equipped with a reflux cooling tube. Further, 0.09 g of lithium hydroxide and 200 g of methanol were added, and the mixture was stirred at 60 °C for 6 hours. Then, it was dropped into water, the precipitate was filtered, and vacuum dried to obtain a polymer precursor (S-20).

[0451] Next, 90 parts by mass of N-methylpyrrolidone and 10 parts by mass of the above polymer precursor (S-20) were added to a 300 mL three-necked flask equipped with a reflux cooling tube and a gas inlet plug and dissolved. Then, after introducing nitrogen at a flow rate of 200 mL / min for 10 minutes, the temperature was raised to 75 °C, 5 parts by mass of mercaptopropionic acid and 0.6 parts by mass of azobisisobutyronitrile (manufactured by FUJIFILM Wako Pure Chemical Corporation) were added, and stirring was continued for 5 hours. Then, it was dropped into hexane, and a fluorine-based copolymer S-20 was obtained as a precipitate. After performing vacuum drying at 60 °C for 5 hours, it was dissolved in an arbitrary solvent again. The obtained fluorine-based copolymer was dissolved in butyl butyrate to obtain an adhesive solution S-20 (concentration 10 mass%).

[0452] [Synthesis Example 25: Synthesis of Fluorine-Based Copolymer S-21 and Preparation of Adhesive Solution S-21]

[0453] A fluorine-based copolymer S-21 was synthesized, and an adhesive solution S-21 (concentration 10 mass%) composed of the fluorine-based copolymer was prepared.

[0454] Specifically, 90 parts by mass of N-methylpyrrolidone and 10 parts by mass of the above polymer precursor (S-20) were added to a 300 mL three-necked flask equipped with a reflux cooling tube and a gas inlet plug and dissolved. Then, after introducing nitrogen at a flow rate of 200 mL / min for 10 minutes, the temperature was raised to 75 °C, 3 parts by mass of 6-mercapto-1-hexanol and 0.6 parts by mass of azobisisobutyronitrile (manufactured by FUJIFILM Wako Pure Chemical Corporation) were added, and stirring was continued for 5 hours. Then, 7 parts by mass of maleic anhydride was added, and stirring was further continued for 2 hours. Then, it was dropped into hexane, and a fluorine-based copolymer S-21 was obtained as a precipitate. After performing vacuum drying at 60 °C for 5 hours, it was dissolved in an arbitrary solvent again. The obtained fluorine-based copolymer was dissolved in butyl butyrate to obtain an adhesive solution S-21 (concentration 10 mass%).

[0455] In the fluorine-based copolymer S-21, regarding the content of the constituent component having a functional group selected from the above functional group group (a), the ester bond and the carboxyl group are 0.3 mol%.

[0456] [Synthesis Example 26: Synthesis of Fluorine-based Copolymer S-22 and Preparation of Adhesive Solution S-22]

[0457] The fluorine-based copolymer S-22 was synthesized, and an adhesive solution S-22 (concentration: 10% by mass) composed of this fluorine-based copolymer was prepared.

[0458] Specifically, 90 parts by mass of N-methylpyrrolidone and 10 parts by mass of the above polymer precursor (S-19) were added to a 300 mL three-necked flask equipped with a reflux condenser and a gas inlet plug and dissolved. Then, after introducing nitrogen at a flow rate of 200 mL / min for 10 minutes, the temperature was raised to 75°C, 25 parts by mass of 1H, 1H, 2H, 2H-perfluorodecanethiol and 1 part by mass of 2,2'-azobis(isobutyronitrile) (manufactured by FUJIFILM Wako Pure Chemical Corporation) were added, and stirring was continued for 5 hours. Then, it was dropped into hexane, and the fluorine-based copolymer S-22 was obtained as a precipitate. After subjecting it to reduced-pressure drying at 60°C for 5 hours, it was dissolved in an arbitrary solvent. The obtained fluorine-based copolymer was dissolved in butyl butyrate to obtain an adhesive solution S-22 (concentration: 10% by mass).

[0459] [Synthesis Example 27: Synthesis of Fluorine-based Copolymer S-23 and Preparation of Adhesive Solution S-23]

[0460] The fluorine-based copolymer S-23 was synthesized, and an adhesive solution S-23 (concentration: 10% by mass) composed of this fluorine-based copolymer was prepared.

[0461] Specifically, 90 parts by mass of N-methylpyrrolidone and 10 parts by mass of the fluorine-based copolymer S-17 synthesized in Synthesis Example 20 were added to a 300 mL three-necked flask equipped with a reflux cooling tube and a gas inlet plug and dissolved therein. Then, 32.5 parts by mass of lauryl acrylate (manufactured by FUJIFILM Wako Pure Chemical Corporation), 17.5 parts by mass of 1H,1H,2H,2H-tridecafluorooctyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.1 part by mass of copper chloride (manufactured by FUJIFILM Wako Pure Chemical Corporation), and 0.6 part by mass of 4,4'-dimethyl-2,2'-bipyridine were added. After introducing nitrogen for 10 minutes, nitrogen was introduced at a flow rate of 50 mL / min, the temperature was raised to 100 °C, and stirring was continued for 10 hours. Then, it was dropped into hexane, and the fluorine-based copolymer S-23 was obtained as a precipitate. After performing vacuum drying at 60 °C for 5 hours, it was dissolved in an arbitrary solvent. The obtained fluorine-based copolymer was dissolved in butyl butyrate to obtain an adhesive solution S-23 (concentration: 10% by mass).

[0462] [Synthesis Example 28: Synthesis of Fluorine-Based Copolymer S-24 and Preparation of Adhesive Solution S-24]

[0463] The fluorine-based copolymer S-24 was synthesized, and an adhesive solution S-24 (concentration: 10% by mass) composed of the fluorine-based copolymer was prepared.

[0464] Specifically, 180 parts by mass of tetrahydrofuran and 20 parts by mass of the fluorine-based copolymer S-17 synthesized in Synthesis Example 20 were added to a 500 mL three-necked flask equipped with a reflux cooling tube. Further, 0.12 g of lithium hydroxide and 40 g of methanol were added, and the mixture was stirred at 60 °C for 6 hours. Then, it was dropped into water, the precipitate was filtered, and vacuum drying was performed to obtain a polymer precursor A (S-24).

[0465] Next, 135 parts by mass of N-methylpyrrolidone and 15 parts by mass of the above polymer precursor A (S-24) were added to a 300 mL three-necked flask equipped with a reflux cooling tube and a gas inlet plug and dissolved therein. Then, after introducing nitrogen at a flow rate of 200 mL / min for 10 minutes, the temperature was raised to 75 °C, 18 parts by mass of decanedithiol and 0.9 part by mass of azobisisobutyronitrile (manufactured by FUJIFILM Wako Pure Chemical Corporation) were added, and stirring was continued for 5 hours. Then, it was dropped into hexane, and a polymer precursor B (S-24) was obtained as a precipitate.

[0466] Next, 90 parts by mass of N-methylpyrrolidone and 10 parts by mass of the above polymer precursor B (S-24) were added to a 300 mL three-necked flask equipped with a reflux condenser and a gas inlet plug and dissolved. Then, 2 parts by mass of lauryl acrylate (manufactured by FUJIFILM Wako Pure Chemical Corporation), 1 part by mass of 1H,1H,2H,2H-tridecafluorooctyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), and 0.1 part by mass of azobisisobutyronitrile (manufactured by FUJIFILM Wako Pure Chemical Corporation) were added. After introducing nitrogen for 10 minutes at a flow rate of 200 mL / min, the temperature was raised to 75 °C and stirring was continued for 5 hours. Then, it was dropped into hexane, and a fluorine-based copolymer S-24 was obtained as a precipitate. After subjecting it to reduced-pressure drying at 60 °C for 5 hours, it was dissolved in an arbitrary solvent again. The obtained fluorine-based copolymer was dissolved in butyl butyrate to obtain an adhesive solution S-24 (concentration: 10% by mass).

[0467] For each synthesized polymer, the amount of VDF (content of the VDF constituent), the amount of HFP (content of the HFP constituent), the types and contents of other constituents, and the types and contents of the constituents having functional groups are shown in Table 1. The tensile fracture strain, the weight-average molecular weight, and the SP value were measured by the above respective methods. These results are shown in

[0468] Table 1.

[0469]

[0470] <Abbreviations of the table>

[0471] In the table, "-" in the constituent column indicates that the corresponding constituent is not present.

[0472] -Copolymerization component-

[0473] The compound into which the copolymerization component (other constituent or constituent having a functional group) is introduced is represented by the number of the polymerizable compound having the above functional group.

[0474] A-2: Methacrylic acid (manufactured by Tokyo Chemical Industry Co., Ltd., SP value 18.3)

[0475] A-4: Maleic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd., SP value 26.3)

[0476] A-7: 2-(Methacryloyloxy)ethyl phosphate (SP value 26.3)

[0477] A-11: 2-Hydroxyethyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd., SP value 24.2)

[0478] A-15: Glycidyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd., SP value 22.2)

[0479] In the table, the "*" in the constituent component column of copolymers S-18 to S-24 indicates the constituent component corresponding to that in the chemical structure of each copolymer shown above. For example, in polymer S-19, * indicates the constituent component having a hydroxyhexylthio group in the side chain.

[0480] In addition, when there are two or more types of functional groups in one molecular chain (polymerization chain), any one of the functional groups (omitting the description of ester bonds, etc.) is described in the "functional group" column of Table 1.

[0481] [Synthesis Example 29: Synthesis of Granular Adhesive (A-1) and Preparation of Granular Adhesive Dispersion A-1]

[0482] 7.2 g of a 40% by mass heptane solution of the following macromonomer M-1, 12.4 g of methyl acrylate (MA), 6.7 g of acrylic acid (AA), 207 g of heptane (manufactured by Wako Pure Chemical Corporation), and 1.4 g of azobisisobutyronitrile were added to a 2 L three-necked flask equipped with a reflux condenser and a gas inlet plug. After introducing nitrogen at a flow rate of 200 mL / min for 10 minutes, the temperature was raised to 100°C. A liquid prepared in a separate container (a liquid obtained by mixing 846 g of a 40% by mass heptane solution of macromonomer M-1, 222.8 g of methyl acrylate, 75.0 g of acrylic acid, 300.0 g of heptane, and 2.1 g of azobisisobutyronitrile) was added dropwise thereto over 4 hours. After the dropwise addition was completed, 0.5 g of azobisisobutyronitrile was added. Then, after stirring at 100°C for 2 hours, it was cooled to room temperature and filtered to prepare a granular adhesive dispersion A-1 (concentration 39.2% by mass) composed of propylene polymer (A-1). The average particle diameter of the granular adhesive in this dispersion was 180 nm, and the adsorption rate A SE was 86%.

[0483] (Synthesis Example of Macromonomer M-1)

[0484] A macromonomer M-1 was obtained by reacting a self-condensate (GPC polystyrene standard number average molecular weight: 2,000) of glycidyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) and 12-hydroxystearic acid (manufactured by Wako Pure Chemical Corporation), and polymerizing it with methyl methacrylate and glycidyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) in a ratio of 1:0.99:0.01 (molar ratio) as a macromonomer, and then reacting the resulting polymer with acrylic acid (manufactured by FUJIFILM Wako Pure Chemical Corporation). The SP value of the macromonomer M-1 is 9.3, and the number average molecular weight is 11,000. The SP value and number average molecular weight of the macromonomer are values calculated by the above method.

[0485] [Synthesis Example 30: Synthesis of Granular Binder (A-2) and Preparation of Granular Binder Dispersion A-2]

[0486] 4.46 g of polyethylene glycol (trade name: polyethylene glycol 200, manufactured by FUJIFILM Wako Pure Chemical Corporation), 0.17 g of 2,2-bis(hydroxymethyl)butyric acid (manufactured by Tokyo Chemical Industry Co., Ltd.), and 6.69 g of NISSO-PB GI1000 (trade name, manufactured by Nippon Soda Co., Ltd.) were added to a 200 mL three-necked flask and dissolved in 74 g of THF (tetrahydrofuran). 6.98 g of diphenylmethane diisocyanate (manufactured by FUJIFILM Wako Pure Chemical Corporation) was added to this solution and stirred at 60 °C to dissolve it uniformly. 560 mg of NEOSTAN NU-600 (trade name, manufactured by Nitto Kasei Co., Ltd.) was added to the resulting solution, and the mixture was stirred at 60 °C for 5 hours to obtain a 20% by mass THF solution (polymer solution) of polyurethane (A-2).

[0487] Next, 74 g of THF was added to the polymer solution obtained above, and while stirring at 150 rpm, 222 g of heptane was added dropwise over 10 minutes to obtain an emulsion of polyurethane (A-2). While flowing nitrogen, the emulsion was heated at 85 °C for 120 minutes. 50 g of heptane was added to the obtained residue and further heated at 85 °C for 60 minutes. This operation was repeated 4 times to remove THF. Thus, a heptane dispersion A-2 (concentration 3.3% by mass) of granular binder composed of polyurethane (A-2) was obtained. The average particle size of the granular binder in this dispersion was 90 nm, and the adsorption rate A of the inorganic solid electrolyte SE was 50%.

[0488] [Synthesis Example 31: Synthesis of Polymer S-A1 (Preparation of Binder Solution S-A1)]

[0489] Polymer S-A1 was synthesized, and a butyl butyrate solution S-A1 of this polymer was prepared.

[0490] 11.9 g of styrene (manufactured by FUJIFILM Wako Pure Chemical Corporation), 17.9 g of dodecyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.187 g of maleic anhydride (manufactured by FUJIFILM Wako Pure Chemical Corporation), and 0.36 g of polymerization initiator V-601 (trade name, manufactured by FUJIFILM Wako Pure Chemical Corporation) were added to a 100 mL volumetric flask and dissolved in 36 g of butyl butyrate to prepare a monomer solution.

[0491] 18 g of butyl butyrate was added to a 300 mL three-necked flask, and the above monomer solution was added dropwise while stirring at 80 °C for 2 hours. After the addition was completed, the temperature was raised to 90 °C, and stirring was continued for 2 hours to synthesize polymer S-A1 (vinyl polymer), and a binder solution S-A1 (concentration 40% by mass) composed of polymer S-A1 was obtained.

[0492] The SP value of polymer S-A1 was 19.2 MPa 1 / 2 , the mass average molecular weight was 67,000, and the adsorption rate A of this binder to the inorganic solid electrolyte SE was 0%.

[0493] [Synthesis Example 32: Synthesis of SEBS (S-A2) and Preparation of Binder Solution S-A2]

[0494] The adhesive solution S-A2 composed of SEBS was prepared by synthesizing SEBS (S-A2).

[0495] Specifically, 150 parts by mass of toluene, 30 parts by mass of styrene, 24 parts by mass of ethylene group, and 46 parts by mass of 1,3-butadiene were added to an autoclave, and 1 part by mass of a polymerization initiator V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added. The temperature was raised to 80 °C and stirred for 3 hours. Then, the temperature was raised to 90 °C and the reaction was carried out until the addition conversion rate reached 100%. The obtained solution was precipitated again into methanol, and the obtained solid was dried to obtain the target polymer. The weight-average molecular weight of this polymer was 83,000. Then, after dissolving 50 parts by mass of the polymer obtained above in 50 parts by mass of cyclohexane and 150 parts by mass of THF (tetrahydrofuran), the solution was set at 70 °C, and 3 parts by mass of n-butyllithium, 3 parts by mass of 2,6-di-tert-butyl-p-cresol, 1 part by mass of bis(cyclopentadienyl)titanium dichloride, and 2 parts by mass of diethylaluminum chloride were added. Under a hydrogen pressure of 10 kg / cm 2 The reaction was carried out for 1 hour, distilled off, and dried to obtain SEBS (S-A2). SEBS (S-A2) is a random copolymer with a weight-average molecular weight of 83,000.

[0496] The obtained SEBS (S-A2) was dissolved in butyl butyrate to prepare an adhesive solution S-A2 with a concentration of 10% by mass.

[0497] The styrene content of the polymer S-A2 was 23.8 mol%, and the SP value was 17.9 MPa 1 / 2 , and the adsorption rate A of this adhesive to the inorganic solid electrolyte SE was 0%.

[0498] [Synthesis Example 33: Synthesis of SEBS (S-A3) and Preparation of Adhesive Solution S-A3]

[0499] In the above Synthesis Example 31, 3 parts by mass of 2,6-di-tert-butyl-p-cresol and 0.3 parts by mass of maleic anhydride were added to 100 parts by mass of the polymer obtained by reprecipitation, and the reaction was carried out at 180 °C for 5 hours. The obtained solution was precipitated again into methanol, and the obtained solid was dried to obtain the target polymer. The weight-average molecular weight of this polymer was 89,000. Then, after dissolving 50 parts by mass of the polymer obtained above in 50 parts by mass of cyclohexane and 150 parts by mass of THF (tetrahydrofuran), the solution was set at 70 °C, and 3 parts by mass of n-butyllithium, 3 parts by mass of 2,6-di-tert-butyl-p-cresol, 1 part by mass of bis(cyclopentadienyl)titanium dichloride, and 2 parts by mass of diethylaluminum chloride were added. Under a hydrogen pressure of 10 kg / cm 2The following reaction was carried out for 1 hour, and then distilled off and dried to obtain SEBS (S-A3). SEBS (S-A3) is a random copolymer with a weight-average molecular weight of 89,000.

[0500] The obtained SEBS (S-A3) was dissolved in butyl butyrate to prepare an adhesive solution S-A3 with a concentration of 10% by mass.

[0501] The styrene content of polymer S-A3 is 23.8 mol%, and the SP value is 17.9 MPa 1 / 2 , and the adsorption rate A of this adhesive to the inorganic solid electrolyte SE is 2%.

[0502] 2. Synthesis of sulfide-based inorganic solid electrolyte

[0503] [Synthesis Example A]

[0504] The sulfide-based inorganic solid electrolyte was synthesized with reference to the non-patent literatures 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.

[0505] Specifically, 2.42 g of lithium sulfide (Li2S, manufactured by Aldrich.Inc, purity > 99.98%) and 3.90 g of phosphorus pentasulfide (P2S5, manufactured by Aldrich.Inc, purity > 99%) were weighed separately in a glove box under an argon atmosphere (dew point -70 °C), and then put into an agate mortar and mixed with an agate pestle for 5 minutes. The mixing ratio of Li2S and P2S5 was set to Li2S:P2S5 = 75:25 in terms of molar ratio.

[0506] Next, 66 g of zirconia beads with a diameter of 5 mm were put into a 45 mL zirconia container (manufactured by Fritsch Co., Ltd.), and the total amount of the above mixture of lithium sulfide and phosphorus pentasulfide was put in. The container was completely sealed under an argon atmosphere. The container was set in a planetary ball mill P-7 (trade name, manufactured by Fritsch Co., Ltd.), and mechanically milled at a rotation speed of 510 rpm for 20 hours at a temperature of 25 °C, thereby obtaining 6.20 g of a yellow powder sulfide-based inorganic solid electrolyte (Li-P-S-based glass, hereinafter sometimes referred to as LPS). The particle size of the Li-P-S-based glass was 15 μm.

[0507] [Example 1]

[0508] <Preparation of Composition Containing Inorganic Solid Electrolyte>

[0509] 60 g of zirconia beads with a diameter of 5 mm were put into a 45 mL zirconia container (manufactured by Fritsch Japan Co., Ltd.). When using 2.8 g of LPS synthesized in Synthesis Example A above, 0.08 g or 0.04 g (solid component mass) of a fluorine-containing binder solution that satisfies the content shown in Table 2-2, and 0.04 g of a fluorine-containing binder solution, 0.04 g (solid component mass) of a granular binder dispersion shown in Table 2-2 and butyl butyrate were further put in so that the content in the butyl butyrate composition became 50% by mass as a dispersion medium. Then, the container was set in a planetary ball mill P-7 (trade name, manufactured by Fritsch Co., Ltd.). The composition (slurry) containing the inorganic solid electrolyte, SE-1 to SE-4, was prepared by mixing at a temperature of 25 °C and a rotation speed of 150 rpm for 10 minutes.

[0510] <Preparation of Composition for Positive Electrode>

[0511] Into a 45 mL zirconia container (manufactured by Fritsch Japan Co., Ltd.), 60 g of zirconia beads with a diameter of 5 mm were added. 2.8 g of the LPS synthesized in Synthesis Example A was added, and the dispersion medium shown in Table 2-1 was added as a dispersion medium so that the content in the composition became 50% by mass. The container was set in a planetary ball mill P-7 (trade name) manufactured by Fritsch Co., Ltd., and stirred at 200 rpm at 25°C for 30 minutes. Thereafter, 13.2 g of NMC (manufactured by Sigma-Aldrich Co. LLC) as a positive electrode active material, 0.32 g of acetylene black (AB) as a conductive assistant, 0.16 g or 0.08 g (solid component mass) of the fluorine-containing binder solution shown in Table 2-1, and when using 0.08 g of the fluorine-containing binder solution, 0.08 g (solid component mass) of the granular binder dispersion or chain polymerization polymer binder solution shown in Table 2-1 was further added. The container was set in the planetary ball mill P-7 and continuously mixed at 25°C and 200 rpm for 30 minutes to prepare positive electrode compositions (slurries) P-1 to P-24, respectively.

[0512] In the positive electrode composition P-24, the average particle diameter of the polymer binder composed of polymer S-26 was 890 nm.

[0513] <Preparation of negative electrode composition>

[0514] Into a 45 mL zirconia container (manufactured by Fritsch Japan Co., Ltd.), 60 g of zirconia beads with a diameter of 5 mm were added. When using 2.8 g of the LPS synthesized in Synthesis Example A, 0.067 g or 0.034 g (solid component mass) of the fluorine-containing binder solution shown in Table 2-2, and in the case of 0.034 g of the fluorine-containing binder solution, 0.034 g (solid component mass) of the granular binder dispersion shown in Table 2-2 and the dispersion medium shown in Table 2-2 were further added so that the content in the composition became 50% by mass. The container was set in a planetary ball mill P-7 (trade name) manufactured by Fritsch Co., Ltd., and mixed at 300 rpm at 25°C for 60 minutes. Thereafter, 3.53 g of silicon (Si, manufactured by Aldrich, CO. LTD.) was added as a negative electrode active material, and 0.27 g of VGCF (manufactured by SHOWA DENKO K.K.) was added as a conductive assistant. Similarly, the container was set in the planetary ball mill P-7 and mixed at 25°C and 100 rpm for 10 minutes to prepare negative electrode compositions (slurries) N-1 to N-17, respectively.

[0515] Regarding each fluorine-containing binder prepared in each synthesis example, the adsorption rate A of the inorganic solid electrolyte (the inorganic solid electrolyte used to prepare each composition) shown in Tables 2-1 and 2-2 (collectively referred to as Table 2) was measured. SE The adsorption rate A of the active material (the active material used to prepare each composition) shown in the same table was measured. AM And the peel strength from the aluminum foil was measured. The two adsorption rates were measured by the following method, and the peel strength was measured by the above method. Moreover, for each composition, the difference (absolute value) between the SP value of the fluorine-based copolymer forming the fluorine-containing binder and the SP value of the dispersion medium was calculated. These results are shown in Table 2. In addition, the form (dissolved or granular) of the fluorine-containing binder in the composition is shown. In addition, in the positive electrode compositions P-21 to P-23, the chain polymerization polymer binder is dissolved in the dispersion medium.

[0516] In Table 2, the content of the dispersion medium in the whole composition is shown, and the content of other components (solid particles) is shown as the content in 100 mass% of the solid components in the composition. The units are all mass%, but the description is omitted in Table 2.

[0517] In addition, Table 2 shows the SP values of the fluorine-based copolymer forming the fluorine-containing binder and the dispersion medium. The unit of the SP value and the difference (absolute value) of the SP value is MPa 1 / 2 However, the description is omitted in Table 2.

[0518] [Measurement of the adsorption rate A of the polymer binder to the inorganic solid electrolyte SE

[0519] The adsorption rate A was measured using the inorganic solid electrolyte, the polymer binder, and the dispersion medium used to prepare each composition containing the inorganic solid electrolyte shown in Table 2. SE .

[0520] That is, the polymer binder was dissolved in the dispersion medium to prepare a 1 mass% binder solution. At a ratio such that the mass ratio of the polymer binder to the inorganic solid electrolyte in the binder solution was 42:1, the binder solution and the inorganic solid electrolyte were placed in a 15 mL medicine bottle and stirred at 80 rpm for 1 hour at room temperature by a mixing rotor and then allowed to stand.

[0521] The supernatant obtained by solid-liquid separation was filtered through a filter with a pore size of 1 μm, and all of the obtained filtrate was dried to dryness, and the mass (the mass of the polymer binder not adsorbed to the inorganic solid electrolyte) W of the polymer binder dissolved in the filtrate was measured. A From this mass W A and the mass W of the polymer binder contained in the binder solution used for the measurement B ​, the adsorption rate of the polymer binder relative to the inorganic solid electrolyte is calculated by the following formula.

[0522] Adsorption rate A of the polymer binder SE is set as the average value of the adsorption rates obtained by performing the above measurement twice.

[0523] Adsorption rate (%) = [(W B - W A ) / W B × 100

[0524] In addition, the adsorption rate A was measured using the inorganic solid electrolyte and the polymer binder taken out from the formed solid electrolyte layer, and the dispersion medium for preparing the composition containing the inorganic solid electrolyte. SE The same value was obtained.

[0525] [Measurement of the adsorption rate A of the polymer binder to the active material AM

[0526] The adsorption rate A was measured using the active material, the polymer binder, and the dispersion medium for preparing each electrode composition shown in Table 2. AM .

[0527] In the above "measurement of the adsorption rate A SE ", the active material was used instead of the inorganic solid electrolyte, and except for this, the adsorption rate A was measured in the same manner as in the above "measurement of the adsorption rate A SE ". AM .

[0528] In addition, the adsorption rate A was measured using the active material and the polymer binder taken out from the formed active material layer, and the dispersion medium for preparing the electrode composition. AM The same value was obtained.

[0529]

[0530]

[0531] <Abbreviations of tables, etc.>

[0532] The contents are all mass ratios (mass %) in the solid components of the composition.

[0533] LPS: LPS synthesized in Synthesis Example A

[0534] NMC: LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2

[0535] Si: Silicon ​

[0536] Gr: Graphite (manufactured by CGB20, Nippon Graphite Industries, Co., Ltd., average particle size 20 μm)

[0537] AB: Acetylene black

[0538] VGCF: Carbon nanotube (manufactured by SHOWA DENKO K.K.)

[0539] For SE layer: Composition for solid electrolyte layer

[0540] <Fabrication of solid electrolyte sheet for all-solid-state secondary battery>

[0541] Using a baking applicator (product name: SA-201, manufactured by TESTER SANGYO CO., LTD.), each of the compositions SE-1 to SE-4 containing an inorganic solid electrolyte obtained above was coated on an aluminum foil with a thickness of 20 μm, heated at 80 °C for 2 hours, and the composition containing the inorganic solid electrolyte was dried (removing the dispersion medium). Then, using a hot press, the dried composition containing the inorganic solid electrolyte was heated and pressed at a temperature of 120 °C and a pressure of 40 MPa for 10 seconds to fabricate solid electrolyte sheets SE-1 to SE-4 for all-solid-state secondary batteries, respectively. The film thickness of the solid electrolyte layer was 50 μm.

[0542] <Fabrication of positive electrode sheet for all-solid-state secondary battery>

[0543] Using a baking applicator (product name: SA-201), each of the positive electrode compositions P-1 to P-24 obtained above was coated on an aluminum foil with a thickness of 20 μm, heated at 80 °C for 1 hour, further heated at 110 °C for 1 hour, and the composition containing the inorganic solid electrolyte was dried (removing the dispersion medium). Then, using a hot press, the dried positive electrode composition was pressed at 25 °C (10 MPa, 1 minute) to fabricate positive electrode sheets P-1 to P-24 for all-solid-state secondary batteries each having a positive electrode active material layer with a film thickness of 100 μm, respectively.

[0544] <Fabrication of negative electrode sheet for all-solid-state secondary battery>

[0545] Using a baking applicator (product name: SA-201), each of the obtained positive electrode compositions N-1 to N-17 was coated on an aluminum foil with a thickness of 20 μm, heated at 80°C for 1 hour, further heated at 110°C for 1 hour, and the composition containing the inorganic solid electrolyte was dried (removing the dispersion medium). Then, using a hot press, the dried negative electrode composition was pressed at 25°C (10 MPa, 1 minute), and negative electrode sheets N-1 to N-17 for all-solid-state secondary batteries having a negative electrode active material layer with a film thickness of 70 μm were respectively produced.

[0546] <Evaluation 1: Dispersion stability>

[0547] Each of the prepared compositions was put into a glass test tube with a diameter of 10 mm and a height of 4 cm up to a height of 4 cm, and left standing at 25°C for 24 hours. The reduction rate of the solid content in the upper 30% (height) of the slurry before and after standing was calculated from the above formula. According to which of the following evaluation criteria the solid content reduction rate was included in, the ease (precipitability) of precipitation of the inorganic solid electrolyte and the active material was evaluated as the dispersion stability of the composition. In this test, the smaller the solid content reduction rate, the more excellent the dispersion stability, and a level of "F" or above in the evaluation criteria was the qualified level. The results are shown in Table 3.

[0548] Reduction rate of solid content (%) = [(Solid content concentration in the upper 30% before standing - Solid content concentration in the upper 30% after standing) / Solid content concentration in the upper 30% before standing] × 100

[0549] - Evaluation criteria -

[0550] A: Solid content reduction rate < 1%

[0551] B: 1% ≤ Solid content reduction rate < 10%

[0552] C: 10% ≤ Solid content reduction rate < 20%

[0553] D: 20% ≤ Solid content reduction rate < 30%

[0554] E: 30% ≤ Solid content reduction rate < 40%

[0555] F: 40% ≤ Solid content reduction rate < 50%

[0556] G: 50% ≤ Solid content reduction rate

[0557] <Evaluation 2: Processability>

[0558] In the same manner as for each of the prepared compositions, except for the dispersion medium, with the same mixing ratio, the amount of the dispersion medium was reduced to prepare a slurry having a solid component concentration of 75% by mass. 2 mL of polyspot (manufactured by Atect Corporation) was vertically arranged so that the tip 10 mm was below the slurry interface, and the slurry was suctioned for 10 seconds at 25°C, and the mass W of the polyspot containing the suctioned slurry was measured. When the tare weight (self-weight) of the polyspot was set as W0, the case where the slurry mass W - W0 was less than 0.1 g was judged as being unable to be suctioned with a dropper. When the slurry could not be sucked with a dropper, the upper limit solid component concentration at which it could be sucked with a dropper while gradually adding the dispersion medium was determined. Based on which of the following evaluation criteria the obtained upper limit solid component concentration was included in, the processability of the composition (whether it has an appropriate viscosity to form a flat and good-surfaced formed layer) was evaluated. The solid component concentration was calculated by placing 0.30 g of the prepared slurry on an aluminum cup and heating it at 120°C for 2 hours to distill off the dispersion medium.

[0559] In this test, the higher the above upper limit solid component concentration, the more excellent the processability, and the level above the evaluation criterion "F" was the qualified level. The results are shown in Table 3.

[0560] - Evaluation criteria -

[0561] A: Upper limit solid component concentration ≥ 70% by mass

[0562] B: 70% by mass > upper limit solid component concentration ≥ 60% by mass

[0563] C: 60% by mass > upper limit solid component concentration ≥ 50% by mass

[0564] D: 50% by mass > upper limit solid component concentration ≥ 40% by mass

[0565] E: 40% by mass > upper limit solid component concentration ≥ 30% by mass

[0566] F: 30% by mass > upper limit solid component concentration ≥ 20% by mass

[0567] G: 20% by mass > upper limit solid component concentration

[0568] <Evaluation 3: Current collector adhesion (vibration test)>

[0569] The negative electrode thin sheet for all-solid-state secondary battery or the positive electrode thin sheet for all-solid-state secondary battery produced is punched into a disc-shaped test piece with a diameter of 10 mm, placed on the bottom surface of a 15 mL medicine bottle (inner diameter 20 mm), and the disc-shaped test piece is not fixed with the active material layer facing upward, and then sealed. The medicine bottle is fixed to a test tube mixer (trade name: Delta Mixer Se-40, TIETECH Co., Ltd.) and vibrated for 30 seconds (total number of vibrations 1400 times) at an amplitude of 5 mm.

[0570] After this vibration test, for the disc-shaped test piece taken out from the medicine bottle, the peeling ratio of the active material layer (notched active material layer) peeled from the current collector was calculated by the following formula. According to which of the following evaluation criteria the obtained peeling ratio was included in, the current collector adhesion was evaluated. In this test, the smaller the above peeling ratio, the higher the adhesion between the current collector and the active material, the excellent current collector adhesion, and the evaluation standard of "F" or above was the qualified level. The results are shown in Table 3.

[0571] Peeling ratio (%) = [Total area of the peeled active material layer (projected area) / Area before the vibration test] × 100

[0572] -Evaluation Criteria-

[0573] A: 0% = Peeling ratio

[0574] B: 0% < Peeling ratio < 10%

[0575] C: 10% ≤ Peeling ratio < 30%

[0576] D: 30% ≤ Peeling ratio < 50%

[0577] E: 50% ≤ Peeling ratio < 70%

[0578] F: 70% ≤ Peeling ratio < 90%

[0579] G: 90% ≤ Peeling ratio

[0580] [Table 3]

[0581]

[0582] <Manufacture of All-Solid-State Secondary Battery>

[0583] <Manufacture of Batteries for Evaluating Positive Electrode Sheets (No.P-1 to P-24) for All-Solid-State Secondary Batteries>

[0584] Each positive electrode sheet for all-solid-state secondary batteries produced was stamped into a disk shape with a diameter of 10 mm and placed in a PET cylinder with an inner diameter of 10 mm. 30 mg of LPS synthesized in Synthesis Example A was placed on the positive electrode active material layer side inside the cylinder, and SUS rods with a diameter of 10 mm were inserted through the openings at both ends of the cylinder. A pressure of 350 MPa was applied to the current collector side of the positive electrode sheet for all-solid-state secondary batteries and LPS by the SUS rods for pressing. After temporarily removing the SUS rod on the LPS side, a disk-shaped In sheet (thickness 20 μm) with a diameter of 9 mm and a disk-shaped Li sheet (thickness 20 μm) with a diameter of 9 mm were inserted onto the LPS inside the cylinder in this order. The removed SUS rod was inserted into the cylinder again and fixed under a pressure of 50 MPa. Thus, all-solid-state secondary batteries (half-cells) No.C-1 to C-23 and C-45 with a structure of aluminum foil (thickness 20 μm) - positive electrode active material layer (thickness 80 μm) - solid electrolyte layer (thickness 200 μm) - negative electrode active material (counter electrode) layer (In / Li sheet, thickness 30 μm) were obtained.

[0585] <Manufacture of batteries for evaluating negative electrode sheets (N-1 to N-17) for all-solid-state secondary batteries>

[0586] Each negative electrode sheet for all-solid-state secondary batteries produced was stamped into a disk shape with a diameter of 10 mm and placed in a polyethylene terephthalate (PET) cylinder with an inner diameter of 10 mm. 30 mg of LPS synthesized in Synthesis Example A was placed on the negative electrode active material layer side inside the cylinder, and stainless steel (SUS) rods with a diameter of 10 mm were inserted through the openings at both ends of the cylinder. A pressure of 350 MPa was applied to the current collector side of the negative electrode sheet for all-solid-state secondary batteries and LPS by the SUS rods for pressing. After temporarily removing the SUS rod on the LPS side, a disk-shaped indium (In) sheet (thickness 20 μm) with a diameter of 9 mm and a disk-shaped lithium (Li) sheet (thickness 20 μm) with a diameter of 9 mm were inserted onto the LPS inside the cylinder in this order. The removed SUS rod was inserted into the cylinder again and fixed under a pressure of 50 MPa. Thus, all-solid-state secondary batteries (half-cells) No.C-24 to C-27 and C-32 to C-44 with a structure of copper foil (thickness 20 μm) - negative electrode active material layer (thickness 60 μm) - solid electrolyte layer (thickness 200 μm) - positive electrode active material (counter electrode) layer (In / Li sheet, thickness 30 μm) were obtained.

[0587] (Manufacture of batteries for evaluating solid electrolyte sheets (SE-1 to SE-4) for all-solid-state secondary batteries)

[0588] The positive electrode sheets P-4 or P-14 for all-solid-state secondary batteries were punched into discs with a diameter of 10 mm and placed into a PET cylinder with an inner diameter of 10 mm. On the side of the positive electrode active material layer within the cylinder, the solid electrolyte sheets for all-solid-state secondary batteries shown in Table 4 were punched into discs with a diameter of 10 mm and placed into the cylinder. SUS rods with a diameter of 10 mm were inserted through the openings at both ends of the cylinder. A pressure of 350 MPa was applied to the current 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 through the SUS rods for pressing. 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, a disc-shaped In sheet with a diameter of 9 mm (thickness 20 μm) and a disc-shaped Li sheet with a diameter of 9 mm (thickness 20 μm) were sequentially inserted onto the solid electrolyte layer of the solid electrolyte sheet for all-solid-state secondary batteries within the cylinder. The removed SUS rod was inserted into the cylinder again and fixed under a pressure of 50 MPa. Thus, all-solid-state secondary batteries (half cells) No.C-28 to C-31 with a structure of aluminum foil (thickness 20 μm) - positive electrode active material layer (thickness 80 μm) - solid electrolyte layer (thickness 45 μm) - negative electrode active material (counter electrode) layer (In / Li sheet, thickness 30 μm) were obtained.

[0589] <Evaluation 4: Cycling performance>

[0590] For each of the fabricated all-solid-state secondary batteries, the discharge capacity retention rate was measured using a charge-discharge evaluation device TOSCAT-3000 (trade name, manufactured by TOYO SYSTEM Co., Ltd.).

[0591] Specifically, each all-solid-state secondary battery was charged at 25°C until the current density reached 0.1 mA / cm 2 and the battery voltage reached 3.6 V. Then, it was discharged until the current density reached 0.1 mA / cm 2 and the battery voltage reached 2.5 V. One charge and one discharge were regarded as one charge-discharge cycle, and the initialization was repeated for 3 cycles under the same conditions. Then, the above charge-discharge cycles were repeated, and the discharge capacity of each all-solid-state secondary battery was measured using the charge-discharge evaluation device: TOSCAT-3000 (trade name) each time the charge-discharge cycle was performed.

[0592] When the discharge capacity (initial discharge capacity) of charging and discharging in the first cycle after initialization is set to 100%, the number of charge-discharge cycles when the discharge capacity retention rate (discharge capacity relative to the initial discharge capacity) reaches 80% is used to evaluate the battery performance (cycle characteristics) by including which of the following evaluation criteria. In this test, the higher the evaluation criterion, the more excellent the battery performance (cycle characteristics), and the initial battery performance can be maintained even after repeated charge and discharge (even after long-term use).

[0593] In addition, the initial discharge capacities of the all-solid-state secondary batteries of the present invention all show sufficient values to function as all-solid-state secondary batteries.

[0594] -Evaluation Criteria-

[0595] A: 500 cycles or more

[0596] B: More than 300 cycles and less than 500 cycles

[0597] C: More than 200 cycles and less than 300 cycles

[0598] D: More than 150 cycles and less than 200 cycles

[0599] E: More than 80 cycles and less than 150 cycles

[0600] F: More than 40 cycles and less than 80 cycles

[0601] G: Less than 40 cycles

[0602] [Table 4]

[0603]

[0604] From the results shown in Table 3 and Table 4, the following can be known.

[0605] In the comparative examples of the composition containing an inorganic solid electrolyte that does not use a fluorine-containing binder and a dispersion medium formed of a specific fluorine-based copolymer that satisfies a specific adsorption rate, both the dispersion stability and the processability are poor. Also, the current collector adhesion of the electrode sheet having a constituent layer formed of this composition is poor, and the cycle characteristics of the all-solid-state secondary battery are insufficient.

[0606] In contrast, the composition containing an inorganic solid electrolyte of the present invention that uses a fluorine-containing binder, a dispersion medium, and an inorganic solid electrolyte formed of a specific fluorine-based copolymer that satisfies a specific adsorption rate has both high-level dispersion stability and processability. By using this composition containing an inorganic solid electrolyte to form a constituent layer of an all-solid-state secondary battery, the current collector adhesion of the obtained electrode sheet can be made firm, and an improvement in cycle characteristics can be achieved for the obtained all-solid-state secondary battery.

[0607] The present invention has been described together with its embodiments, but unless otherwise specified, the present invention is not limited in any of the details of the description, and is considered to be widely interpreted as long as it does not depart from the main intention and scope of the invention shown in the claims.

[0608] This application claims priority based on Japanese Patent Application No. 2019-157944 filed in Japan on August 30, 2019, Japanese Patent Application No. 2019-193350 filed in Japan on October 24, 2019, and Japanese Patent Application No. 2020-088767 filed in Japan on May 21, 2020. All of them are incorporated by reference and their contents are incorporated as part of what is described in this specification.

[0609] Symbol Explanation

[0610] 1 - negative electrode current collector, 2 - negative electrode active material layer, 3 - solid electrolyte layer, 4 - positive electrode active material layer, 5 - positive electrode current collector, 6 - working part, 10 - all-solid-state secondary battery.

Claims

1. A composition containing an inorganic solid electrolyte, which contains: 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, wherein, the polymer binder includes a polymer binder composed of a fluorine-based copolymer, the fluorine-based copolymer includes a vinylidene fluoride constituent and a hexafluoropropylene constituent of 30 to 50 mol%, and the tensile fracture strain of the fluorine-based copolymer is 500% or more, in the fluorine-based copolymer, the content of the constituent derived from a fluorine-containing polymerizable compound other than vinylidene fluoride and hexafluoropropylene is 10 mol% or less, in the dispersion medium, the adsorption rate of the polymer binder composed of the fluorine-based copolymer to the inorganic solid electrolyte is less than 60%, the polymer binder composed of the fluorine-based copolymer is dissolved in the dispersion medium, the weight average molecular weight of the fluorine-based copolymer is 50,000 to 1,500,000.

2. The composition containing an inorganic solid electrolyte according to claim 1, wherein, the tensile fracture strain is 700% or more.

3. The composition containing an inorganic solid electrolyte according to claim 1, wherein, the peel strength of the polymer binder composed of the fluorine-based copolymer to the aluminum foil is 0.1 N / mm or more.

4. The composition containing an inorganic solid electrolyte according to claim 1, wherein, the fluorine-based copolymer includes: a constituent having a functional group selected from the following functional group group (a), <Functional group group (a)> Hydroxyl group, amino group, carboxyl group, sulfo group, phosphoric acid group, phosphonic acid group, thioalkyl group, ether bond, imino group, ester bond, amide bond, urethane bond, urea bond, heterocyclic group, aryl group, carboxylic anhydride group, isocyanate group, alkoxysilyl group, fluoroalkyl group, siloxanyl group.

5. The composition containing an inorganic solid electrolyte according to claim 4, wherein, the content of the constituent having a functional group selected from the functional group group (a) in the fluorine-based copolymer is 0.01 to 10 mol%.

6. The composition containing an inorganic solid electrolyte according to claim 1, wherein, the polymer binder contains a granular binder having an average particle size of 1 to 1000 nm.

7. The composition containing an inorganic solid electrolyte according to claim 1, wherein, the polymer binder contains: a binder composed of a hydrocarbon-based polymer, a binder composed of a (meth)acrylic acid-based polymer, or a polymer binder composed of an ethylene-based polymer.

8. The composition containing an inorganic solid electrolyte according to claim 1, which contains an active material.

9. The composition containing an inorganic solid electrolyte according to claim 8, wherein, the adsorption rate of the polymer binder composed of the fluorine-based copolymer to the active material is 90% or less.

10. The composition containing an inorganic solid electrolyte according to claim 1, which contains a conductive additive.

11. The composition containing an inorganic solid electrolyte according to claim 1, wherein, the inorganic solid electrolyte is a sulfide-based inorganic solid electrolyte.

12. A sheet for an all-solid-state secondary battery, which has a layer composed of the composition containing an inorganic solid electrolyte according to any one of claims 1 to 11.

13. An all-solid-state secondary battery, which sequentially includes 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 solid electrolyte layer, and the negative electrode active material layer is a layer composed of the composition containing an inorganic solid electrolyte according to any one of claims 1 to 11.

14. A method for manufacturing a sheet for an all-solid-state secondary battery, which forms a film of the composition containing an inorganic solid electrolyte according to any one of claims 1 to 11.

15. A method for manufacturing an all-solid-state secondary battery, which manufactures an all-solid-state secondary battery through the manufacturing method according to claim 14.

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