Inorganic solid electrolyte-containing composition, all-solid-state secondary battery and sheet thereof, and manufacturing method of the latter two

Abstract

Provided is an inorganic solid electrolyte-containing composition containing an inorganic solid electrolyte, a dispersion medium, and a component constituting a polymer binder, the component constituting the polymer binder including a dissolvable polymer having a specific functional group or a combination of partial structures.

Description

TECHNICAL FIELD

[0001] The present application relates to an inorganic solid electrolyte-containing composition, a sheet for a full solid-state secondary battery, and a full solid-state secondary battery, and a method for manufacturing a sheet for a full solid-state secondary battery and a full solid-state secondary battery. BACKGROUND

[0002] In a full solid-state secondary battery, all of the negative electrode, the electrolyte, and the positive electrode are composed of solids, and it is possible to greatly improve the safety or reliability, which are problems of a battery using an organic electrolyte. Also, it is possible to extend the life. Furthermore, the full solid-state secondary battery can be configured in a structure in which electrodes and electrolytes are arranged in series. Therefore, compared with a secondary battery using an organic electrolyte, it is possible to be high in energy density, and it is expected to be applied to an electric vehicle or a large-scale storage battery or the like.

[0003] In such a full solid-state secondary battery, as a substance forming a constituent layer (a solid electrolyte layer, a negative electrode active material layer, a positive electrode active material layer, or the like), an inorganic solid electrolyte, an active material, or the like can be cited. The inorganic solid electrolyte, particularly, an oxide-based inorganic solid electrolyte and a sulfide-based inorganic solid electrolyte have been attracting attention in recent years as an electrolyte material having high ion conductivity close to that of an organic electrolyte.

[0004] As a material forming a constituent layer of a full solid-state secondary battery (a constituent layer-forming material), a material containing the above-described inorganic solid electrolyte or the like has been proposed. For example, Patent Literature 1 describes a solid electrolyte composition including an inorganic solid electrolyte (A) having ion conductivity of a metal ion belonging to Group 1 or Group 2 of the periodic table, binder particles (B) having an average particle diameter of 10 nm or more and 1,000 nm or less, and a polymer composed of a macromonomer (X) having a number average molecular weight of 1,000 or more as a side chain component, and a dispersion medium (C).

[0005] Prior Art Documents

[0006] Patent Literature

[0007] Patent Literature 1: Japanese Patent Application Publication No. 2015-088486 SUMMARY

[0008] Technical Problem to be Solved by the Invention

[0009] Since the constituent layer of the full solid-state secondary battery is formed of solid particles (inorganic solid electrolyte, active material, conductive aid, or the like), the interface contact state of the solid particles with each other is limited, and the interface resistance easily increases (ion conductivity decreases).

[0010] As the interfacial resistance of the solid particles to each other rises, the battery resistance of the all-solid-state secondary battery also rises. In addition, the rise in the battery resistance is further accelerated due to the voids between the solid particles generated in the charge and discharge of the all-solid-state secondary battery, and thus leads to a decrease in the cycle characteristics of the all-solid-state secondary battery.

[0011] The increase in the battery resistance is not only due to the interfacial contact state of the solid particles to each other, but also due to the uneven presence (arrangement) of the solid particles in the constituent layer, and even due to the surface flatness of the constituent layer. Therefore, when the constituent layer is formed from a constituent layer forming material, the constituent layer forming material is required not only to have the dispersibility of the solid particles immediately after preparation, but also to have a property (dispersion stability) of stably maintaining the dispersibility of the solid particles immediately after preparation and a property (handleability) of easily forming a coating film having a flat surface (good surface property).

[0012] However, Patent Literature 1 does not study based on such a viewpoint. In recent years, research and development of high performance and practical use of electric vehicles are rapidly progressing, and the requirements for the battery performance (for example, cycle characteristics) required for all-solid-state secondary batteries are becoming higher.

[0013] The present application has an object to provide an inorganic solid electrolyte-containing composition having excellent dispersion stability and handleability, which can achieve further suppression of the rise in the battery resistance and excellent cycle characteristics by being used as a constituent layer forming material for an all-solid-state secondary battery. Also, the present application has an object to provide a sheet for an all-solid-state secondary battery and an all-solid-state secondary battery using the inorganic solid electrolyte-containing composition, and a method for manufacturing a sheet for an all-solid-state secondary battery and an all-solid-state secondary battery.

[0014] Means for solving the technical problem

[0015] The present inventors have found, as a result of various studies focusing on a polymer binder used with solid particles such as an inorganic solid electrolyte, that as a polymer binder used with an inorganic solid electrolyte and a dispersion medium, the polymer binder is in a dissolved state as an adhesive precursor in an inorganic solid electrolyte-containing composition, and the adhesive precursor is allowed to react to solidify or precipitate the polymer binder at the time of film formation, and thus the above problems can be solved.

[0016] That is, in the inorganic solid electrolyte-containing composition containing an inorganic solid electrolyte and a dispersion medium, a dissoluble polymer that exhibits solubility to the dispersion medium is introduced with a functional group or a partial structure that exhibits reactivity to each other, respectively, and thus it is possible to suppress the re-agglomeration or precipitation of the solid particles such as the inorganic solid electrolyte over time, and at the same time, it is possible to form a coating film with a flat surface. Further, it is found that when film formation is performed using the inorganic solid electrolyte-containing composition, the above-mentioned functional group or partial structure of the dissoluble polymer is chemically reacted with each other to generate a binder, and at the same time, it is solidified or precipitated, and thus it is possible to suppress the increase in the interfacial resistance while bonding the inorganic solid electrolytes to each other. As a result, it is found that by using the inorganic solid electrolyte-containing composition as a constituent layer-forming material, it is possible to form a constituent layer with a flat surface that is formed by suppressing the increase in the interfacial resistance between the solid particles while bonding the solid particles to each other, and it is possible to manufacture an all-solid-state secondary battery that can achieve the increase in the battery resistance and excellent cycle characteristics.

[0017] The present application has been further developed based on these insights, and thus the present application has been completed.

[0018] That is, the above-mentioned problem is solved by the following solutions.

[0019] <1> An inorganic solid electrolyte-containing composition containing an inorganic solid electrolyte having conductivity of an ion of a metal belonging to Group 1 or Group 2 of the periodic table, a component constituting a polymer binder, and a dispersion medium, wherein

[0020] The component constituting the polymer binder contains at least one of the polymers defined in (C1) and (C2) below.

[0021] (C1) a dissoluble polymer C1-I having at least one functional group or a partial structure selected from the following Group (I) and a dissoluble polymer C1-II having at least one functional group or a partial structure selected from the following Group (II)

[0022] (C2) a dissoluble polymer C2 having at least one functional group or a partial structure selected from the following Group (I) and the following Group (II), respectively

[0023] Group (I): a hydroxyl group, a primary amino group or a secondary amino group, a 1,3-dicarbonyl structure

[0024] Group (II): a blocked isocyanate group, a boric acid group or a borinic acid group, a borate group or a borinic acid ester group, an acid anhydride structure

[0025] <2> The inorganic solid electrolyte-containing composition according to <1>, wherein

[0026] At least one of the dissolving polymers has 50 mass% or more of a constituent derived from a (meth)acrylic monomer or a vinyl monomer.

[0027] <3> The inorganic solid electrolyte-containing composition according to <1> or <2>, wherein

[0028] The inorganic solid electrolyte is a sulfide-based inorganic solid electrolyte.

[0029] <4> The inorganic solid electrolyte-containing composition according to any one of <1> to <3>, wherein

[0030] The dispersion medium contains at least one selected from a ketone compound, an aliphatic compound, and an ester compound.

[0031] <5> The inorganic solid electrolyte-containing composition according to any one of <1> to <4>, which contains an active material.

[0032] <6> The inorganic solid electrolyte-containing composition according to any one of <1> to <5>, which contains an electrically conductive aid.

[0033] <7> A sheet for a full solid-state secondary battery, which has a layer composed of the inorganic solid electrolyte-containing composition according to any one of <1> to <6>.

[0034] <8> A full solid-state secondary battery, which has, in order, a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer, wherein

[0035] 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 inorganic solid electrolyte-containing composition according to any one of <1> to <6>.

[0036] <9> A method for manufacturing a sheet for a full solid-state secondary battery, which forms a film of the inorganic solid electrolyte-containing composition according to any one of <1> to <6>.

[0037] <10> A method for manufacturing a full solid-state secondary battery, which manufactures a full solid-state secondary battery by the method for manufacturing a sheet according to <9>.

[0038] Effects of the Invention

[0039] The present application can provide an inorganic solid electrolyte-containing composition having excellent dispersion stability and handling properties (dispersion properties), which can achieve further suppression of an increase in battery resistance (increase in ion conductivity) and excellent cycle properties by being used as a constituent layer-forming material for a solid-state secondary battery. Furthermore, the present application can provide a sheet for a solid-state secondary battery having a layer formed of the inorganic solid electrolyte-containing composition and a solid-state secondary battery. In addition, the present application can provide a method for manufacturing a sheet for a solid-state secondary battery and a solid-state secondary battery using the inorganic solid electrolyte-containing composition.

[0040] The above features and other features and advantages of the present application will be more apparent from the appropriate reference to the accompanying drawings and from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a longitudinal sectional view schematically showing a solid-state secondary battery according to a preferred embodiment of the present application.

[0042] Figure 2 is a longitudinal sectional view schematically showing a button-type solid-state secondary battery produced in an example.

[0043] Figure 3 is a view for explaining a layer thickness measurement site in a treatment test in an example. DETAILED DESCRIPTION

[0044] In the present application, a numerical range represented by "to" means a range including a lower limit value and an upper limit value represented by the numerical values before and after "to".

[0045] In the present application, the expression of a compound (for example, when called with a compound attached at the end) means that it includes a salt thereof, an ion thereof, in addition to the compound itself. Furthermore, it means that a derivative in which a part such as a substituent to be introduced is changed within a range not impairing the effects of the present application is included.

[0046] In the present application, (meth)acrylic acid means one or both of acrylic acid and methacrylic acid. The same applies to (meth)acrylate.

[0047] In the present application, regarding a substituent, a linking group, and the like (hereinafter, referred to as a substituent or the like) which is not explicitly described as substituted or unsubstituted, it means that it can have an appropriate substituent on the group. Therefore, in the present application, even if simply described as a YYY group, the YYY group further includes a form having a substituent in addition to a form not having a substituent. The same applies to the meaning of a compound which is not explicitly described as substituted or unsubstituted. As a preferred substituent, for example, the substituent Z described later can be mentioned.

[0048] In the present application, when or while or selectively a plurality of substituents or the like represented by a specific symbol is prescribed, it means that each of the substituents or the like can be the same as or different from each other. Also, even if not particularly described, when a plurality of substituents or the like are adjacent, it means that these can be linked to or fused with each other to form a ring.

[0049] In the present application, polymer means a polymer, but has the same meaning as so-called high molecular compound. Also, polymer adhesive means an adhesive composed of a polymer, including a polymer itself and an adhesive formed by containing a polymer.

[0050] [Inorganic solid electrolyte-containing composition]

[0051] The inorganic solid electrolyte-containing composition of the present application contains an inorganic solid electrolyte having ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, a component constituting a polymer adhesive, and a dispersion medium.

[0052] The component constituting a polymer adhesive contained in the inorganic solid electrolyte-containing composition constitutes a polymer adhesive in a constituting layer formed from the inorganic solid electrolyte-containing composition, and functions as a binder that binds solid particles to each other (for example, inorganic solid electrolytes to each other, inorganic solid electrolytes and active materials, active materials to each other) such as inorganic solid electrolytes (furthermore, active materials that can coexist, conductive aids). Also, it functions as a binder that binds a current collector and solid particles.

[0053] The component constituting a polymer adhesive (also referred to as a precursor compound of a polymer adhesive) contains a polymer (combination of polymers) prescribed in at least one of the following (C1) and (C2) in the inorganic solid electrolyte-containing composition. In the present application, each polymer prescribed in (C1) or (C2) can be combined, but preferably contains a polymer prescribed in either one of (C1) and (C2).

[0054] It is considered that the two kinds of dissolvable polymers C1 prescribed in (C1) or the dissolvable polymer C2 prescribed in (C2) exist in the inorganic solid electrolyte-containing composition without chemical reaction of functional groups or partial structures selected from the following groups (I) or (II) in the dissolvable polymers to each other or in the dissolvable polymers, and a part thereof (for example, a range capable of maintaining solubility or dispersion properties to a dispersion medium) can constitute a polymer adhesive. On the other hand, the polymer adhesive is formed in a constituting layer by being composed of the dissolvable polymer prescribed in the following (C1) or (C2), for example, the functional groups or partial structures possessed by these dissolvable polymers are chemically bonded (covalently bonded) when a coating film is formed.

[0055] (C1) a dissolving polymer C1-I having at least one functional group or partial structure selected from the following Group (I) and a dissolving polymer C1-II having at least one functional group or partial structure selected from the following Group (II)

[0056] (C2) a dissolving polymer C2 having at least each one functional group or partial structure selected from the following Group (I) and the following Group (II), respectively

[0057] - Group (I) -

[0058] hydroxyl group, primary amino group or secondary amino group, 1,3-dicarbonyl structure

[0059] - Group (II) -

[0060] blocked isocyanate group, boronic acid group or pinacol boronic acid group, boronic ester group or pinacol boronic ester group, acid anhydride structure

[0061] In the inorganic solid electrolyte-containing composition, the component constituting the polymer binder, the polymer binder can have or not have a function of binding the solid particles to each other.

[0062] The inorganic solid electrolyte-containing composition of the present application is preferably a slurry in which an inorganic solid electrolyte is dispersed in a dispersion medium. In the inorganic solid electrolyte-containing composition, the dissolving polymer defined in (C1) or (C2) above is dissolved in the dispersion medium, and at least one of the dissolving polymers C1-I and C1-II defined in (C1) or the dissolving polymer C2 defined in (C2) has a function of adsorbing to the solid particles such as the inorganic solid electrolyte and dispersing them in the dispersion medium. Here, the adsorption of the dissolving polymer to the solid particles includes not only physical adsorption but also chemical adsorption (adsorption by formation of a chemical bond, adsorption by electron donation and acceptance, etc.).

[0063] The inorganic solid electrolyte-containing composition of the present application is excellent in dispersion stability and handleability. By using the inorganic solid electrolyte-containing composition as a layer-forming material constituting a layer, a sheet for a full solid-state secondary battery having a low-resistance layer excellent in surface flatness and surface properties, and a full solid-state secondary battery excellent in cycle characteristics can be realized.

[0064] In a method of forming an active material layer on a current collector from the inorganic solid electrolyte-containing composition of the present application, the adhesion of the current collector to the active material layer is also excellent, and the cycle characteristics can be further improved.

[0065] The detailed reason is not clear, but it is considered as follows. That is, it is considered that in the inorganic solid electrolyte-containing composition, as a component constituting the polymer binder, the soluble polymer defined by the above (C1) or (C2) is generally dissolved in the dispersion medium in a state in which the functional group or the partial structure selected from the above groups (I) or (II) does not undergo chemical reaction, and is appropriately adsorbed to the solid particles while maintaining the dissolved state in the dispersion medium. Therefore, not only after the inorganic solid electrolyte-containing composition is just prepared, but also over time, the re-aggregation or precipitation of the inorganic solid electrolyte, and the like, can be inhibited, the high dispersibility after preparation is stably maintained (excellent dispersion stability), and the viscosity is also inhibited from excessively increasing, and thus a good flowability is exhibited, and thus the planarity of the coating film surface (excellent handling property) can be achieved.

[0066] On the other hand, if the inorganic solid electrolyte-containing composition of the present application is used to form the constituent layer, the functional group or the partial structure of the soluble polymer chemically reacts and the soluble polymer is high-molecular-weighted at the time of film formation of the constituent layer (for example, at the time of coating the inorganic solid electrolyte-containing composition, and further at the time of drying). It is considered that, as this high-molecular-weighting proceeds, the polymer binder is formed, and cannot maintain the solubility with respect to the dispersion medium and is solidified or precipitated, and does not entirely coat the surface of the solid particles, but partially coats (adsorbs). Thereby, the contact of the solid particles with each other is not hindered by the presence of the polymer binder, and the solid particles can be bonded to each other while the ion conduction path is sufficiently constructed by the contact of the solid particles with each other (the increase in the interfacial resistance of the solid particles with each other is inhibited).

[0067] Further, the inorganic solid electrolyte-containing composition of the present application maintains the dispersion properties (dispersion stability and handling property) at the time of film formation of the constituent layer. Thereby, it is considered that the deviation of the contact state of the solid particles in the constituent layer (the arrangement of the solid particles in the constituent layer is made uniform) can be inhibited, and the uniform contact (adhesion) of the solid particles is ensured. In addition to this, the inorganic solid electrolyte-containing composition is easily subjected to film formation, and at the time of film formation, the inorganic solid electrolyte-containing composition appropriately flows (is leveled), and becomes a constituent layer which does not have surface roughness due to insufficient flow or excessive flow, and further does not have surface roughness due to clogging of the discharge portion at the time of film formation, and the like (the planarity of the film surface is excellent). In this way, it is considered that a sheet for a full solid-state secondary battery having a constituent layer which is flat in the surface (uniform in the layer thickness) and has low resistance (high conductivity) can be achieved.

[0068] The full solid-state secondary battery having the constituent layer exhibiting the above-described properties exhibits excellent cycle characteristics even if repeated charging and discharging under ordinary conditions.

[0069] In the all-solid-state secondary battery for an electric vehicle, further increase in battery resistance, decrease in cycle characteristics become early and significant due to high output charge and discharge (high speed charge and discharge) toward practical use. However, the all-solid-state secondary battery of the present application can perform high speed charge and discharge at a large current in addition to charge and discharge under ordinary conditions. Also, even in high speed charge and discharge, generation of voids due to expansion and contraction of active material and the like can be effectively suppressed, and excellent cycle characteristics can be achieved.

[0070] When the active material layer is formed from the inorganic solid electrolyte-containing composition of the present application, as described above, the layer is formed while maintaining the highly (uniformly) dispersed state immediately after preparation. Therefore, it is considered that the contact (adhesion) of the polymer binder to the current collector surface is not hindered by the solid particles preferentially undergoing precipitation and the like, and the polymer binder can contact (adhere to) the current collector surface in a state dispersed with the solid particles. Thus, the electrode sheet for an all-solid-state secondary battery in which the active material layer is formed on the current collector from the inorganic solid electrolyte-containing composition of the present application can achieve firm adhesion of the current collector to the active material. Also, the all-solid-state secondary battery in which the active material layer is formed on the current collector from the inorganic solid electrolyte-containing composition of the present application exhibits firm adhesion of the current collector to the active material and can achieve further improvement in cycle characteristics and conductivity.

[0071] The inorganic solid electrolyte-containing composition of the present application exhibits the above-described excellent characteristics, and thus can be preferably used as a sheet material for an all-solid-state secondary battery (including an electrode sheet for an all-solid-state secondary battery) or a forming material (layer-forming material) for a solid electrolyte layer or an active material layer of an all-solid-state secondary battery. In particular, it can be preferably used as a forming material for a negative electrode sheet or a negative electrode active material layer for an all-solid-state secondary battery containing a negative electrode active material that greatly expands and contracts due to charge and discharge, and in this mode, high cycle characteristics and high conductivity can also be achieved.

[0072] The inorganic solid electrolyte-containing composition of the present application is preferably a non-aqueous composition. In the present application, the non-aqueous composition includes a mode in which the water content is preferably 500 ppm or less in addition to a mode in which water is not contained. In the non-aqueous composition, the water content is more preferably 200 ppm or less, further preferably 100 ppm or less, and particularly preferably 50 ppm or less. If the inorganic solid electrolyte-containing composition is a non-aqueous composition, deterioration of the inorganic solid electrolyte can be suppressed. The water content indicates the amount of water contained in the inorganic solid electrolyte-containing composition (proportion to the mass of the inorganic solid electrolyte-containing composition), and specifically, is the value obtained by filtering with a 0.02 μm membrane filter and measuring by Karl Fischer titration.

[0073] The inorganic solid electrolyte-containing composition of the present application also contains an active material, and a conductive aid, etc. (The composition of this type is referred to as an electrode composition.)

[0074] Next, the components contained in the inorganic solid electrolyte-containing composition of the present application and the components that can be contained are described.

[0075] <Inorganic Solid Electrolyte>

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

[0077] In the present application, the inorganic solid electrolyte refers to an inorganic solid electrolyte, and the solid electrolyte refers to a solid electrolyte that can move ions within it. From the viewpoint of not containing an organic substance as a main ion-conducting material, it is clearly distinguished from an organic solid electrolyte (a polymer electrolyte typified by polyethylene oxide (PEO), an organic electrolyte salt typified by lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)). Also, since the inorganic solid electrolyte is solid in a stable state, it is generally not dissociated or ionized into cations and anions. In this point, it is clearly distinguished from an inorganic electrolyte salt (LiPF6, LiBF4, lithium bis(fluorosulfonyl)imide (LiFSI), LiCl, etc.) that is dissociated or ionized into cations and anions in an electrolyte or a polymer. As long as the inorganic solid electrolyte has ion conductivity of a metal ion belonging to Group 1 or Group 2 of the periodic table, there is no particular limitation, and it generally does not have electron conductivity. In the case of the all-solid-state secondary battery of the present application being a lithium ion battery, it is preferable that the inorganic solid electrolyte has ion conductivity of a lithium ion.

[0078] The above inorganic solid electrolyte can be appropriately selected and used from solid electrolyte materials generally used for all-solid-state secondary batteries. 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 given, and from the viewpoint of being able to form a more favorable interface between the active material and the inorganic solid electrolyte, the sulfide-based inorganic solid electrolyte is preferable.

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

[0080] The sulfide-based inorganic solid electrolyte preferably contains a sulfur atom, and has ion conductivity of a metal ion belonging to Group 1 or Group 2 of the periodic table, and has a compound having electron insulating properties. The sulfide-based inorganic solid electrolyte preferably contains at least Li, S, and P as elements, and has lithium ion conductivity, but other elements other than Li, S, and P can be contained depending on the purpose or the situation.

[0081] As the sulfide-based inorganic solid electrolyte, for example, a lithium ion-conductive inorganic solid electrolyte satisfying a 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, and is preferably Li. M represents an element selected from B, Zn, Sn, Si, Cu, Ga, Sb, Al, and Ge. A represents an element selected from I, Br, Cl, and F. a1 to e1 represent the composition ratio of each element, and a1 : b1 : c1 : d1 : e1 satisfies 1 to 12 : 0 to 5 : 1 : 2 to 12 : 0 to 10. a1 is preferably 1 to 9, and more preferably 1.5 to 7.5. b1 is preferably 0 to 3, and more preferably 0 to 1. d1 is preferably 2.5 to 10, and more preferably 3.0 to 8.5. e1 is preferably 0 to 5, and more preferably 0 to 3.

[0084] As described below, the composition ratio of each element can be controlled by adjusting the compounding amount of the raw material compounds at the time of manufacturing the sulfide-based inorganic solid electrolyte.

[0085] The sulfide-based inorganic solid electrolyte can be amorphous (glass), can be crystallized (glass-ceramized), or can be only a part thereof. 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, for example, a reaction of at least two or more kinds of raw materials among lithium sulfide (Li2S), phosphorus sulfide (for example, diphosphorus pentasulfide (P2S5)), monomer phosphorus, monomer sulfur, sodium sulfide, hydrogen sulfide, lithium halide (for example, Lil, LiBr, LiCl), and sulfides of the elements represented by the above M (for example, SiS2, SnS, GeS2).

[0087] The ratio of Li2S to P2S5 in the Li-P-S-based glass and the Li-P-S-based glass-ceramic is preferably 60:40 to 90:10, and more preferably 68:32 to 78:22, in terms of the molar ratio of Li2S:P2S5. By setting the ratio of Li2S to P2S5 to this range, the lithium ion conductivity can be improved. Specifically, the lithium ion conductivity can be preferably set to 1 x 10 -4 S / cm or more, and more preferably 1 x 10 -3S / cm or more. Although there is no particular upper limit, it is actually 1 x 10 -1 S / cm or less.

[0088] As specific examples of the sulfide inorganic solid electrolyte, combinations of raw materials are exemplified 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 and the like. Among them, the mixing ratio of each raw material is not limited. As a method for synthesizing a sulfide inorganic solid electrolyte material using such a raw material combination, for example, a non-crystallization method can be exemplified. As the non-crystallization method, for example, a mechanical polishing method, a solution method, and a melt quenching method can be exemplified. The processing at ordinary temperature can be performed, and thus the simplification of the manufacturing process can be achieved.

[0089] (ii) Oxide inorganic solid electrolyte

[0090] The oxide inorganic solid electrolyte preferably contains an oxygen atom, and has ionic conductivity of a metal ion belonging to Group 1 or Group 2 of the periodic table, and has electronic insulating property.

[0091] As the ionic conductivity of the oxide inorganic solid electrolyte, 1 x 10 -6 S / cm or more, more preferably 5 x 10 -6 S / cm or more, more preferably 5 x 10 -5 S / cm or more. Although there is no particular upper limit, it is actually 1 x 10 -1 S / cm or less.

[0092] As specific examples of the compound, for example, Li xa La ya TiO3〔xa satisfies 0.3 ≤ xa ≤ 0.7, ya satisfies 0.3 ≤ ya ≤ 0.7.〕(LLT); Li xb La yb Zr zb M bb mb O nb (M bb is one or more elements selected from the group consisting of Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In, and Sn. xb satisfies 5 ≤ xb ≤ 10, yb satisfies 1 ≤ yb ≤ 4, zb satisfies 1 ≤ zb ≤ 4, mb satisfies 0 ≤ mb ≤ 2, and nb satisfies 5 ≤ nb ≤ 20.); Li xc B yc M cc zc O nc (M cc is one or more elements selected from the group consisting of C, S, Al, Si, Ga, Ge, In, and Sn. xc satisfies 0 < xc ≤ 5, yc satisfies 0 < yc ≤ 1, zc satisfies 0 < zc ≤ 1, and nc satisfies 0 < nc ≤ 6.); Li xd (Al, Ga) yd (Ti, Ge) zd Si ad P md O nd (xd satisfies 1 ≤ xd ≤ 3, yd satisfies 0 ≤ yd ≤ 1, zd satisfies 0 ≤ zd ≤ 2, ad satisfies 0 ≤ ad ≤ 1, md satisfies 1 ≤ md ≤ 7, and nd satisfies 3 ≤ nd ≤ 13.); Li (3-2xe) M ee xe D ee O (xe represents a number of 0 or more and 0.1 or less, M ee represents a metal atom having a valence of 2. 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; Li6BaLa2Ta2O12 Li3PO4 (4-3 / 2w) N w (w satisfies w < 1); Li 3.5 Zn 0.25 GeO4; La 0.55 Li 0.35 TiO3; LiTi2P3O 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 12 (LLZ), and the like.

[0093] Also, a phosphorus compound containing Li, P, and O is also preferable. For example, lithium phosphate (Li3PO4); LiPON in which a part of the oxygen element in lithium phosphate is substituted with a nitrogen element; LiPOD 1 (D 1 Preferably, the element is one or more selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Ag, Ta, W, Pt, and Au.

[0094] Further, LiA 1 ON(A 1 is one or more selected from the group consisting of Si, B, Ge, Al, C, and Ga.

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

[0096] The halide-based inorganic solid electrolyte preferably contains a halogen atom, and is a compound having ionic conductivity of a metal ion belonging to Group 1 or Group 2 of the periodic table, and having electronic insulating property.

[0097] There is no particular limitation on the halide-based inorganic solid electrolyte, and for example, compounds such as LiCl, LiBr, Lil, Li3YBr6, Li3YCl6, and the like described in ADVANCED MATERIALS, 2018, 30, 1803075 can be mentioned. Among them, Li3YBr6and Li3YCl6are preferable.

[0098] (iv) a hydride-based inorganic solid electrolyte

[0099] The hydride-based inorganic solid electrolyte preferably contains a hydrogen atom, and has ionic conductivity of a metal ion belonging to Group 1 or Group 2 of the periodic table, and has electronic insulating property.

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

[0101] The inorganic solid electrolyte is preferably a particle. In this case, the particle diameter (volume average particle diameter) of the inorganic solid electrolyte is not particularly limited, and is preferably 0.01 μm or more, and more preferably 0.1 μm or more. As an upper limit, it is preferably 100 μm or less, and more preferably 50 μm or less.

[0102] The measurement of the particle diameter of the inorganic solid electrolyte is performed by the following steps. In a 20 mL sample bottle, an inorganic solid electrolyte particle is diluted with water (heptane in the case of a substance unstable to water) to prepare a 1 mass% dispersion liquid. The diluted dispersion liquid sample is irradiated with ultrasonic waves of 1 kHz for 10 minutes, and then immediately used in the test. Using this dispersion liquid sample, and using a laser diffraction / scattering type particle size distribution measuring device LA-920 (trade name, manufactured by HORIBA, Ltd.) and a quartz cell for measurement at a temperature of 25°C, data collection is performed 50 times to obtain the volume average particle diameter. Other detailed conditions and the like are referred to as necessary in Japanese Industrial Standards (JIS) Z8828:2013 "Particle Size Analysis - Dynamic Light Scattering Method". Five samples are prepared for each level, and the average value thereof is used.

[0103] The inorganic solid electrolyte can contain one, or two or more.

[0104] In the case where the solid electrolyte layer is formed, the mass (mg) of the inorganic solid electrolyte per unit area (cm 2 ) of the solid electrolyte layer (unit area weight) is not particularly limited. It can be appropriately determined in accordance with the designed battery capacity, and for example, it can be set to 1 to 100 mg / cm 2 .

[0105] In the case where the inorganic solid electrolyte-containing composition contains an active material as described later, the unit area weight of the inorganic solid electrolyte is preferably such 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 inorganic solid electrolyte-containing composition is not particularly limited, and from the viewpoint of adhesiveness and further from the viewpoint of dispersibility, it is preferably 50% by mass or more, more preferably 70% by mass or more, and particularly preferably 90% by mass or more, in 100% by mass of the solid content. From the same viewpoints, 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, as the upper limit.

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

[0108] In the present application, the solid content refers to a component that does not disappear by volatilization or evaporation when the inorganic solid electrolyte-containing composition is subjected to a drying treatment at 150°C for 6 hours under a nitrogen atmosphere at a gas pressure of 1 mmHg. Typically, it refers to a component other than the dispersion medium described later.

[0109] <Components of the polymer binder>

[0110] The inorganic solid electrolyte-containing composition of the present application contains at least one of the soluble polymers defined in (C1) and (C2) described below as a component of the polymer binder that functions as a binder in the layer to be formed. In the present application, when the inorganic solid electrolyte-containing composition contains components of the polymer binder, it includes not only a mode in which the soluble polymer of the polymer binder is contained but also a mode in which the polymer binder is generated by chemical reaction of the soluble polymer of the polymer binder.

[0111] (Polymer binder)

[0112] The component constituting the polymer binder is selected from the functional group or partial structure (I) in Group (I) or the functional group or partial structure (II) in Group (II) to form a linking structure (crosslinking structure) or the like by chemical reaction with each other, thereby generating the polymer binder. The polymer binder contained in the layer thus formed can be said to be a chemical reaction product of the dissolvable polymer defined in (C1) or (C2). Here, the details of the chemical reaction of the functional group or partial structure are described later, but the chemical structure of the polymer binder thus formed is not uniquely determined depending on the kind of the functional group or partial structure, but it is preferable to be a chemical reaction product of a (meth)acrylic or vinyl polymer. The more the number of linking structures formed by the chemical reaction, preferably intermolecular chemical reaction, of the dissolvable polymer (polymer binder), the higher the molecular weight, and the lower the solubility in the dispersion medium. Thus, it is possible to maintain the adhesion function of the solid particles to each other while effectively suppressing the increase in the interfacial resistance.

[0113] The polymer binder formed by the chemical reaction of the functional group or partial structure has a structure in which a plurality of molecules (dissolvable polymers) are complexly linked, and as a structure that can be used as a polymer binder, a crosslinking structure (mesh structure) or the like can be cited, but it is difficult to adopt a core-shell structure.

[0114] The polymer binder contained in the layer can be one or two or more.

[0115] In the present application, in the case where the layer contains the polymer binder, in addition to the mode containing the polymer binder, there is included a mode containing the component (dissolvable polymer) constituting the polymer binder (residual).

[0116] (Component constituting polymer binder)

[0117] The component constituting the polymer binder is at least one of the combination of the dissolvable polymer C1-I defined in (C1) and C1-II and the dissolvable polymer C2 defined in (C2).

[0118] (C1) The combination of the dissolvable polymer C1-I having at least one functional group or partial structure selected from the following Group (I) and dissolving in the dispersion medium contained in the inorganic solid electrolyte composition and the dissolvable polymer C1-II having at least one functional group or partial structure selected from the following Group (II) and dissolving in the dispersion medium contained in the inorganic solid electrolyte composition

[0119] In the combination of the above (C1), the functional group or partial structure (I) of the dissolving polymer C1-I and the functional group or partial structure (II) of the dissolving polymer C1-II chemically react to constitute the polymer binder.

[0120] (C2) a dissolving polymer C2 having at least each one of the functional group or partial structure selected from the following Group (I) and the following Group (II), respectively

[0121] The dissolving polymer C2 constitutes the polymer binder by the functional group or partial structure (I) and the functional group or partial structure (II) thereof chemically reacting by itself. Therefore, the dissolving polymer C2 can also be called a self-bonding dissolving polymer. The dissolving polymer C2 preferably chemically reacts with another molecule of the dissolving polymer C2.

[0122] - Group (I) -

[0123] hydroxyl group, primary amino group or secondary amino group, 1,3-dicarbonyl structure

[0124] - Group (II) -

[0125] blocked isocyanate group, boronic acid group or pinacolylboronic acid group, boronic acid ester group or pinacolylboronic acid ester group, acid anhydride structure

[0126] First, the functional group or partial structure (I) and (II) contained in the dissolving polymer will be described.

[0127] The functional group or partial structure (I) is a hydroxyl group, primary amino group, secondary amino group, and 1,3-dicarbonyl structure.

[0128] In the present application, the hydroxyl group does not include -OH constituting an acidic group such as carboxyl group.

[0129] The secondary amino group includes imino group (-NH-) in addition to -NHR I (R I represents a substituent group. As the R I The substituent group that can be used is not particularly limited, and a group selected from the substituent group Z described later can be given, and from the viewpoint of reactivity, an alkyl group or aryl group is preferred, and an alkyl group is more preferred, and an alkyl group having 1 to 6 carbon atoms is further preferred. The imino group does not include an imino group bonded to an atom constituting a main chain via a carbonyl group (for example, an imino group in an amide bond bonded to an olefinically unsaturated group in a (meth)acrylamide compound or the like). Also, the imino group can be introduced into a constituting component as a polyalkylene imine chain, polyalkylene diamine chain, or the like in combination with an alkylene group or the like, for example. On the other hand, an imino group contained in an imide bond (-CO-NH-CO-) is preferably not included.

[0130] 1,3-dicarbonyl structure refers to a -CO-CHR I -CO- bond. R I represents a hydrogen atom or a substituent (preferably, selected from substituents Z described later), and is preferably a hydrogen atom from the viewpoint of reactivity. As the above 1,3-dicarbonyl compound, a general compound can be used without particular limitation, and examples thereof can include 1,3-diketone compounds, acetoacetic acid compounds, and the like. As the 1,3-diketone compound, examples thereof can include acetylacetone, 3-methyl-2,4-pentanedione, trifluoroacetylacetone, benzoylacetone, and the like. As the acetoacetic acid compound, examples thereof can include acetoacetic acid, acetoacetic acid ester compounds, acetoacetic acid amide compounds, and the like. The acetoacetic acid ester compound can include aliphatic saturated or unsaturated hydrocarbon, aromatic hydrocarbon, or heterocyclic ester compounds of acetoacetic acid.

[0131] As the functional group or partial structure (I), a hydroxyl group or an amino group is preferred, a hydroxyl group is more preferred from the viewpoint of dispersing properties, and an amino group is more preferred from the viewpoint of resistance and cycle properties.

[0132] The functional group or partial structure (II) is a blocked isocyanate group, a boronic acid group, a borinic acid group, a boronic ester group, a borinic ester group, and an acid anhydride structure.

[0133] The blocked isocyanate group is a group obtained by blocking (protecting) an isocyanate group (-NCO) with a blocking agent, and the blocking agent can be used without particular limitation as a compound generally used for protecting an isocyanate group, and for example, the description of Japanese Patent No. 6254185 can be referred to. As the blocking agent, specifically, examples thereof can include oxime compounds, lactam compounds, phenol compounds, alcohol compounds, amine compounds, amidine compounds, active methylene compounds, pyrazole compounds, thiol compounds, imidazole compounds, imide compounds, and the like. Among them, from the viewpoint of performing a deprotection reaction under mild conditions (for example, the film formation conditions (drying temperature) described later), oxime compounds, lactam compounds, phenol compounds, alcohol compounds, amine compounds, amidine compounds (for example, N,N'-dibenzylformamidine), active methylene compounds, or pyrazole compounds are preferred, and oxime compounds or pyrazole compounds are more preferred. As the oxime compound, examples thereof can include oxime, ketoxime, and specifically, acetone oxime, formaldehyde oxime, cyclohexane oxime, methyl ethyl ketone oxime, cyclohexanone oxime, benzophenone oxime, and the like. Also, as the pyrazole compound, examples thereof can include pyrazole, methylpyrazole, dimethylpyrazole, and the like.

[0134] The boronic acid group and the borinic acid group are groups derived from boric acid (H3BO3), and the boronic acid group is a group (-B(OH)2) obtained by removing one hydroxyl group from boric acid, and the borinic acid group is a group (>B(OH)) obtained by removing two hydroxyl groups from boric acid.

[0135] A boronate group is a group (-B(OR II )2) in which at least one of the hydroxyl groups of a boronic acid group is esterified. Two R II independently represent a hydrogen atom or a substituent, and at least one of the R II is a substituent. The two R II in the boronate group can be bonded to each other to form a ring structure including an -0-B-0- bond. A borinylate group is a group (>B(OR II ) in which the hydroxyl group of a borinic acid group is esterified. R II in the borinylate group represents a substituent. The R II in each of the above ester groups is not particularly limited, and a group selected from the substituents Z described below can be given, and from the viewpoint of reactivity, an alkyl group or an aryl group is preferred, and an alkyl group is more preferred.

[0136] The anhydride structure is a structure obtained by performing a dehydration reaction from a compound having two or more acid groups, and is preferably a structure of anhydrous carboxylic acid (also referred to as a dicarboxylic anhydride structure, a straight chain structure or a ring structure including a -CO-O-CO- bond).

[0137] The carboxylic anhydride group is not particularly limited, and includes a group obtained by removing one or more hydrogen atoms from a carboxylic anhydride (for example, a group represented by the following formula (2a)), and further a constituent itself obtained by copolymerization of a polymerizable carboxylic anhydride as a copolymerizable compound (for example, a constituent represented by the following formula (2b)). As the group obtained by removing one or more hydrogen atoms from a carboxylic anhydride, a group obtained by removing one or more hydrogen atoms from a cyclic carboxylic anhydride is preferred. For example, acetic anhydride, propionic anhydride, benzoic anhydride, maleic anhydride, phthalic anhydride, fumaric anhydride, succinic anhydride, itaconic anhydride, and the like can be given. As the polymerizable carboxylic anhydride, a carboxylic anhydride having an unsaturated bond in the molecule can be given, and a polymerizable cyclic carboxylic anhydride (unsaturated carboxylic anhydride) is preferred. Specifically, maleic anhydride, itaconic anhydride, and the like can be given.

[0138] 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 given, but the present application is not limited thereto. In each formula, * represents a bonding position.

[0139] [Chemical Formula 1]

[0140]

[0141] As the functional group or partial structure (II), from the viewpoint of being able to improve the dispersing properties, the resistance, and the cycle characteristics in a well-balanced manner, an end-capped isocyanate group or an anhydride structure is preferred.

[0142] In the solubilizing polymer used in the present application, the combination of the functional group or moiety (I) and (II) is not particularly limited as long as it is a combination selected from each group, and can be appropriately determined depending on reactivity and the like. For example, a combination of the preferred group of the functional group or moiety (I) and the preferred group of the functional group or moiety (II) is preferred, and a combination of a hydroxyl group or an amino group as the functional group or moiety (I) and a blocked isocyanate group or an acid anhydride structure as the functional group or moiety (II) is more preferred.

[0143] The following shows examples of chemical reactions of the functional group or moiety (I) and the functional group or moiety (II) and the bonds (linking groups, crosslinking groups) formed thereby.

[0144] When a hydroxyl group is selected as the functional group or moiety (I),

[0145] an addition reaction with a blocked isocyanate group forms a urethane bond,

[0146] an exchange reaction with a boronic acid group and a borinic acid group, respectively, with at least one OH group forms a bond with a boron atom,

[0147] an ester exchange reaction with a boronic ester group and a borinic ester group forms a bond with a boron atom,

[0148] an addition reaction with an acid anhydride structure forms a carboxyl group and an ester group.

[0149] When a primary amino group and a secondary amino group are selected as the functional group or moiety (I),

[0150] an addition reaction with a blocked isocyanate group forms a urea bond,

[0151] a dehydration reaction with a boronic acid group and a borinic acid group, respectively, with at least one OH group forms a bond with a boron atom,

[0152] a de-alcoholization reaction with a boronic ester group and a borinic ester group forms a bond with a boron atom,

[0153] an addition reaction with an acid anhydride structure forms a carboxyl group and an amide group.

[0154] When a 1,3-dicarbonyl structure is selected as the functional group or moiety (I),

[0155] an addition reaction with a blocked isocyanate group forms a carbon atom in the α position of the 1,3-dicarbonyl structure (a carbon atom sandwiched between two carbonyl groups) and a carbon-amide bond.

[0156] As the reaction condition, a heating condition can be generally cited, and can be appropriately set depending on the combination of the functional groups or moieties, for example, can be set to 40 to 150°C.

[0157] When the blocked isocyanate group is selected as the functional group or moiety (II), the heating temperature can be set depending on the deprotection temperature of the blocking agent, for example, can be set to 60°C or higher, and further can be set to 80°C or higher, 100°C or higher, 120°C or higher as a high temperature.

[0158] Next, the solubility polymer prescribed in (C1) will be described.

[0159] The component (C1) constituting the polymer binder is a combination of a solubility polymer C1-I having the functional group or moiety (I) and a solubility polymer C1-II having the functional group or moiety (II).

[0160] - Solubility polymers C1-I and C1-II -

[0161] The solubility polymers C1-I and C1-II can each have the above-described functional group or moiety on the main chain of the polymer, but from the viewpoint of reactivity, it is preferable to have it as a substituent or a linker on the side chain, and more preferable to have it as a substituent on the end of the side chain. Among them, the anhydride structure is preferably introduced to the main chain rather than the side chain.

[0162] In the present application, the main chain of the polymer refers to a linear molecular chain other than all the molecular chains constituting the polymer, which can be regarded as a branched chain or a comb-type with respect to the main chain. Although depending on the mass average molecular weight of the molecular chain regarded as a branched chain or a comb-type chain, it is typical that the longest chain among the molecular chains constituting the polymer becomes the main chain. However, the terminal group possessed by the terminal of the polymer is not included in the main chain. Also, the side chain of the polymer refers to the molecular chain other than the main chain, including a short molecular chain and a long molecular chain.

[0163] In the present application, the functional group or moiety on the side chain of the polymer means that the functional group or moiety is bonded to the atom constituting the main chain of the polymer directly or via the following linker.

[0164] There is no particular limitation as the linking group, and groups other than the functional groups or partial structures (I) and (II) can be generally mentioned. Specifically, for example, alkylene groups (the number of carbon atoms is preferably from 1 to 12, more preferably from 1 to 6, further preferably from 1 to 3), alkenylene groups (the number of carbon atoms is preferably from 2 to 6, more preferably from 2 to 3), arylene groups (the number of carbon atoms is preferably from 6 to 24, more preferably from 6 to 10), oxygen atoms, sulfur atoms, imino groups (-NR N -: R N represents a hydrogen atom, an alkyl group having from 1 to 6 carbon atoms, or an aryl group having from 6 to 10 carbon atoms), a carbonyl group, a phosphoric acid linking group (-0-P(OH)(0)-0-), a phosphonic acid linking group (-P(OH)(0)-0-), or a group related to a combination thereof, and the like. It is also possible to combine an alkylene group and an oxygen atom to form a polyalkyleneoxy chain.

[0165] 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 preferable, a group formed by combining an alkylene group, an arylene group, a carbonyl group, an oxygen atom, and an imino group is more preferable, and a group further containing a -CO-O- group, a -CO-N(R N )- group (R N As described above.) or an arylene group is particularly preferable, and a -CO-O-alkylene group, a -CO-N(R N )-alkylene group, a -CO-O-alkylene-O- group, a -CO-N(R N )-alkylene-O- group, a phenylene group, or a phenylene-alkylene-O- group is particularly preferable.

[0166] In the present application, the number of atoms constituting the linking group is preferably from 1 to 36, more preferably from 1 to 24, and further preferably from 1 to 12. The number of linking atoms of the linking group is preferably 10 or less, and 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 linking between the prescribed structural portions. For example, in the case of -CH2-C(=0)-0-, the number of atoms constituting the linking group becomes 6, but the number of linking atoms becomes 3.

[0167] The soluble polymers C1-I and C1-II can have at least one functional group or partial structure (I) or (II), and can also have a plurality of, for example, from 2 to 4.

[0168] The solubility polymer has at least one functional group or moiety structure (I) or (II), respectively, and preferably has a plurality thereof, from the viewpoint of effectively reducing the solubility of the solubility polymer based on chemical reaction, regardless of the number of kinds. In the present application, the number of functional groups or moiety structures possessed by one molecule of the solubility polymer is not dependent on the composition or the like of the solubility polymer, but is appropriately determined in accordance with the number of functional groups or moiety structures possessed by the reactive constituent component described later and the content or the like of the reactive constituent component.

[0169] In (C1), the combination of the functional group or moiety structure (I) of the solubility polymer C1-I and the functional group or moiety structure (II) of the solubility polymer C1-II is not particularly limited, and can be appropriately set. For example, a combination of the preferred group of the functional group or moiety structure (I) and the preferred group of the functional group or moiety structure (II) is preferred, and a combination of a hydroxyl group or an amino group as the functional group or moiety structure (I) and a blocked isocyanate group or an acid anhydride structure as the functional group or moiety structure (II) is more preferred.

[0170] The solubility polymer C1-I can have a functional group or moiety structure (II) capable of reacting with the functional group or moiety structure (I) as long as the solubility of itself is not impaired. The solubility polymer C1-II can also have the functional group or moiety structure (I) as well.

[0171] The solubility polymer C1-I and C1-II each represent the solubility (solubility) with respect to the dispersing medium contained in the inorganic solid electrolyte-containing composition, and is dissolved in the dispersing medium in the inorganic solid electrolyte-containing composition. Thereby, the dispersing properties of the inorganic solid electrolyte-containing composition can be improved.

[0172] In the present application, the dissolution of the polymer in the dispersing medium means, for example, that the solubility is 80% or more in the solubility measurement. The measurement method of the solubility is described below.

[0173] That is, a predetermined amount of the polymer to be measured is weighed in a glass bottle, 100 g of the same kind of dispersing medium as the dispersing medium contained in the inorganic solid electrolyte-containing composition is added thereto, and the mixture is stirred at a temperature of 25°C for 24 hours at a rotation speed of 80 rpm on a mixing rotor. The transmittance of the mixed solution thus obtained after stirring for 24 hours is measured under the following conditions. This test (transmittance measurement) is performed by changing the amount of the polymer to be dissolved (the above-mentioned predetermined amount), and the upper limit concentration X (mass %) at which the transmittance becomes 99.8% is set as the solubility of the polymer with respect to the above-mentioned dispersing medium.

[0174] The solubility of the polymer can be adjusted by the kind or composition (kind or content of the constituent component) of the polymer, the mass average molecular weight, or the like.

[0175] -Transmittance measurement conditions-

[0176] Dynamic light scattering (DLS) measurement

[0177] Apparatus: DLS measuring apparatus DLS-8000 manufactured by Otsuka Electronics Co., Ltd.

[0178] Laser wavelength, output: 488 nm / 100 mW

[0179] Sample cell: NMR tube

[0180] The dissolving polymers C1-I and C1-II can be combined with the same kind or different kinds of polymer species or components, preferably combinations of the chain polymerization polymers described later with each other, more preferably combinations in which at least one is a (meth)acrylic or vinyl polymer, further preferably combinations in which both are (meth)acrylic or vinyl polymers, still further preferably combinations in which both are (meth)acrylic polymers with each other or combinations in which the dissolving polymer C1-I is a vinyl polymer and the dissolving polymer C1-II is a (meth)acrylic polymer, particularly preferably combinations in which the dissolving polymer C1-I is a vinyl polymer and the dissolving polymer C1-II is a (meth)acrylic polymer.

[0181] The dissolving polymers C1-I and C1-II can each be used as a commercially available product or a synthetic product.

[0182] The content of the dissolving polymers C1-I and C1-II in the inorganic solid electrolyte composition is not particularly limited and can be appropriately determined in consideration of the number of functional groups or partial structures possessed by each dissolving polymer, etc.

[0183] If the number of functional groups or partial structures possessed by the dissolving polymer is considered, the ratio of the functional group or partial structure (I) to the functional group or partial structure (II) [functional group or partial structure (I): functional group or partial structure (II)] is ideally 1:1, but in the present application, it can be set to 1:0.01 to 1:10, and from the viewpoint of dispersion properties, resistance, and cycle characteristics, it is preferably 1:0.05 to 1:5, more preferably 1:0.1 to 1:2.

[0184] On the other hand, if the mass of the dissolving polymer is considered, the content of the dissolving polymer C1-I and the dissolving polymer C1-II in the inorganic solid electrolyte composition is not particularly limited, and from the viewpoint of the degree of improvement in dispersion properties, resistance, and cycle characteristics, it is preferably 0.1 to 9.9% by mass, more preferably 0.15 to 3.5% by mass, further preferably 0.25 to 2.5% by mass, particularly preferably 0.25 to 1.5% by mass, in 100% by mass of the solid content.

[0185] The total content of the dissolving polymer C1-I and the dissolving polymer C1-II can be appropriately set within the range satisfying the above-mentioned content, and from the viewpoint of improvement in dispersing properties, resistance, and cycle properties, etc., it is preferably 0.1 to 10.0% by mass, more preferably 0.3 to 7.0% by mass, further preferably 0.5 to 5.0% by mass, and particularly preferably 0.5 to 3.0% by mass, in 100% by mass of the solid content. Also, the mass ratio of the content of the dissolving polymer C1-I to the content of the dissolving polymer C1-II [content of the dissolving polymer C1-I : content of the dissolving polymer C1-II] can be appropriately set within the range satisfying the above-mentioned content of each dissolving polymer, and from the viewpoint of improvement in dispersing properties, resistance, and cycle properties, etc., there is no particular limitation, and for example, it is preferably 1 : 10 to 10 : 1, more preferably 1 : 5 to 5 : 1, and further preferably 1 : 3 to 3 : 1.

[0186] The above-mentioned content of the dissolving polymer C1-I and C1-II is set to the total amount of the dissolving polymer including a chemical reaction when the dissolving polymer C1-II or C1-I of the other one occurs a chemical reaction.

[0187] Next, the component (C2) constituting the polymer binder will be described.

[0188] The dissolving polymer C2 has at least each one of the functional group or the partial structure (I) and the functional group or the partial structure (II), respectively.

[0189] The functional group or the partial structure (I) and (II) that the dissolving polymer C2 has, and the manner of having the functional group or the partial structure on the side chain are the same as those in the above-mentioned dissolving polymer C1-I and C1-II.

[0190] The dissolving polymer C2 can have a plurality of, for example, 2 to 4, of the functional group or the partial structure (I) and (II), as long as it has at least each one of them, respectively.

[0191] Also, the dissolving polymer C2 can have a plurality of the functional group or the partial structure (I) and (II), regardless of the number of kinds, as long as it has at least each one of them, respectively, from the viewpoint of effectively reducing the solubility of the dissolving polymer C2 based on a chemical reaction. In the present application, the number of the functional group or the partial structure (I) and (II) that one molecule of the dissolving polymer C2 has, respectively, is not dependent on the composition of the dissolving polymer, etc., and can be appropriately determined the same as the dissolving polymer C1-I, etc.

[0192] The combination of the functional group or the partial structure (I) and (II) that the dissolving polymer C2 has is not particularly limited, and can be appropriately set, and the above-mentioned preferred combinations of the functional group or the partial structure (I) and (II) in the above-mentioned (C1) can be cited.

[0193] The solubility polymer C2 indicates solubility to a dispersion medium contained in the inorganic solid electrolyte-containing composition, and is dissolved in the dispersion medium in the inorganic solid electrolyte-containing composition. Thereby, the dispersion properties of the inorganic solid electrolyte-containing composition can be improved.

[0194] In the present application, the solubility polymer C2 is dissolved in the dispersion medium, and is identical to the above-described solubility polymer CI-I or the like in the meaning of being dissolved in the dispersion medium, except that the polymers are different.

[0195] The solubility polymer C2 is preferably a chain polymerization polymer described later, more preferably a (meth)acrylic acid or vinyl polymer, further preferably a vinyl polymer, and particularly preferably a vinyl polymer having a constituent derived from a styrene compound.

[0196] The solubility polymer C2 can be a commercially available product, or a synthetic product.

[0197] The inorganic solid electrolyte-containing composition of the present application can contain one or two or more kinds of the solubility polymer C2.

[0198] In the solubility polymer C2, the presence ratio of the functional group or partial structure (I) to the functional group or partial structure (II) in the polymer is not particularly limited, and can be appropriately determined in consideration of the number of the functional group or partial structure possessed by each solubility polymer, and the like. If the number of the functional group or partial structure possessed by the solubility polymer is focused on, the ratio [functional group or partial structure (I) : functional group or partial structure (II)] of the functional group or partial structure (I) to the functional group or partial structure (II) is set in the same range as the ratio of the above-described solubility polymer CI-I and CI-II.

[0199] The content of the solubility polymer C2 in the inorganic solid electrolyte-containing composition is not particularly limited, and is preferably 0.1 to 10.0% by mass, more preferably 0.3 to 7.0% by mass, further preferably 0.5 to 5.0% by mass, and particularly preferably 0.5 to 3.0% by mass, in 100% by mass of the solid content. The above-described content of the solubility polymer C2 is set to include the total amount of the solubility polymer C2 that forms a chemical reaction when the solubility polymer C2 chemically reacts with each other.

[0200] -- Solubility Polymers CI-I, CI-II, and C2 --

[0201] The solubility polymers CI-I, CI-II, and C2 are identical except for the above-described functional group or partial structure and the like possessed in the molecules, and will be described together.

[0202] The dissolvable polymer is not particularly limited as long as it has the above-mentioned functional group or partial structure and shows solubility to the dispersion medium, and a polymer generally used as a binder for all-solid-state secondary batteries can be used without particular limitation. As the polymer constituting the dissolvable polymer, specifically, a step-growth (polycondensation, polyaddition, or polyaddition-condensation) polymer such as a polyurethane, a polyurea, a polyamide, a polyimide, a polyester, a polyether, a polycarbonate, and the like, further a fluoropolymer (fluorine-containing polymer), a hydrocarbon polymer, a vinyl polymer, a (meth)acrylic polymer, and the like can be mentioned. Among them, a vinyl polymer or a (meth)acrylic polymer can be preferably selected.

[0203] The polymer constituting the dissolvable polymers C1-I, C1-II, and C2 is preferably a chain-polymerization polymer, and a polymer having 50% by mass or more of a constituent derived from a (meth)acrylic monomer or a vinyl monomer ((meth)acrylic or vinyl polymer) in the polymer is preferable.

[0204] In the present application, when the polymer is a copolymer, the bonding mode (arrangement) of the copolymer component is not particularly limited, and can be any one of a random copolymer, an alternating copolymer, a block copolymer, a graft copolymer, and the like.

[0205] The (meth)acrylic monomer includes a monomer having a (meth)acryloyloxy group or a (meth)acrylamino group, and a (meth)acrylonitrile compound, and the like. The (meth)acrylic monomer is not particularly limited, and for example, a (meth)acrylic compound, a (meth)acrylate compound, a (meth)acrylamide compound, and a (meth)acrylonitrile compound, further a (meth)acrylic compound having a plurality of imino groups as a secondary amino group (for example, a (meth)acrylic compound having a polyethyleneimine chain), and the like (M) can be mentioned, and a (meth)acrylate compound is preferable. The (meth)acrylate compound is not particularly limited, and for example, an ester such as an aliphatic or aromatic hydrocarbon or an aliphatic or aromatic heterocyclic compound, and the like is mentioned, and an aliphatic hydrocarbon, and particularly an alkyl group is preferable. The number of carbon atoms, the kind or number of heteroatoms of these hydrocarbons, heterocyclic compounds, and the like are not particularly limited, and can be appropriately set. For example, the number of carbon atoms can be set to 1 to 30.

[0206] As the vinyl monomer, a monomer containing a vinyl group other than the (meth)acrylic compound (M) is not particularly limited, and examples thereof include a vinyl group-containing aromatic compound (a styrene compound, a vinyl naphthalene compound, etc.), a vinyl group-containing heterocyclic compound (a vinyl carbazole compound, a vinyl pyridine compound, a vinyl imidazole compound, an aromatic heterocyclic compound containing a vinyl group such as N-vinyl caprolactam, a non-aromatic heterocyclic compound containing a vinyl group, etc.), an allyl compound, a vinyl ether compound, a vinyl ketone compound, a vinyl ester compound, a dialkyl itaconate compound, and a vinyl compound such as an unsaturated carboxylic anhydride. As the vinyl compound, for example, "vinyl monomers" described in Japanese Patent Application Publication No. 2015-88486 can be mentioned.

[0207] As the (meth)acrylic monomer, from the viewpoint of exhibiting or improving the solubility in the dispersion medium, in the (meth)acrylate compound, it is preferable that a constituent component derived from an aliphatic hydrocarbon (preferably an alkyl group) having 4 or more carbon atoms be included. The number of carbon atoms of the aliphatic hydrocarbon group is preferably 6 or more, and more preferably 10 or more. The upper limit is not particularly limited, and is preferably 20 or less, and more preferably 14 or less. The aliphatic hydrocarbon having 4 or more carbon atoms can be a branched structure or a cyclic structure, and is preferably a straight chain structure.

[0208] As the vinyl monomer, from the viewpoint of improving the resistance and cycle characteristics, and the strength of the polymer binder, it is preferable that the solubility polymer include at least one of a constituent component derived from a styrene compound (a styrene constituent component), a constituent component derived from a (meth)acrylic monomer, and a constituent component derived from a vinyl monomer other than the styrene compound.

[0209] Further, as the vinyl monomer, from the viewpoint of the resistance and cycle characteristics, it is preferable that the solubility polymer include a constituent component derived from an unsaturated carboxylic anhydride, and more preferably a constituent component derived from maleic anhydride.

[0210] The solubility polymer can include other constituent components that can be copolymerized.

[0211] The functional group or partial structure (I) and (II) can be introduced into any of the constituent components that constitute the dissolving polymer, but are preferably introduced into a constituent component derived from a (meth)acrylic monomer or a vinyl monomer (preferably a styrene compound), a constituent component of a hydrocarbon polymer described later, and the like. The (meth)acrylic monomer into which the functional group or partial structure (I) and (II) is introduced is preferably a (meth)acrylate compound, more preferably an alkyl ester compound of (meth)acrylic acid having 1 to 6 carbon atoms, and further preferably an alkyl ester compound of (meth)acrylic acid having 1 to 3 carbon atoms. Also, it is preferable that the vinyl monomer have a constituent component derived from the above unsaturated carboxylic anhydride as a functional group or partial structure having an anhydride structure in the main chain (for example, a constituent component represented by the above formula (2b)).

[0212] In the dissolving polymer C2, the functional group or partial structure (I) and (II) can be introduced into the same constituent component, and the chemical reaction proceeds rapidly, and from the viewpoints of dispersing properties, electrical resistance, and cycle properties, it is preferable that the functional group or partial structure (I) and (II) be introduced into different constituent components from each other.

[0213] In the present application, when the constituent component into which the functional group or partial structure (I) or (II) is introduced is distinguished from the constituent component into which the functional group or partial structure (I) and (II) is not introduced, it is referred to as a reactive constituent component for convenience.

[0214] Specific examples of the constituent component having the functional group or partial structure (I) and the constituent component having the functional group or partial structure (II) are shown in the following and examples, but the present application is not limited to these. In the following specific examples, Bu represents a n-butyl group, Ph represents a phenyl group, iPr represents an isopropyl group, and n is an integer of 1 to 50.

[0215] [Chemical Formula 2]

[0216]

[0217] There is no particular limitation on the vinyl polymer that is more preferably used as the dissolving polymer, and for example, a polymer containing 50% by mass or more of a constituent component derived from a vinyl monomer other than the (meth)acrylic compound (M) can be cited. As the vinyl monomer, the above vinyl compound and the like can be cited. As the vinyl polymer, polyvinyl alcohol, polyvinyl acetal, polyvinyl acetate, or a copolymer containing these, and the like can be included.

[0218] The vinyl polymer preferably has a constituent component derived from a vinyl monomer and a reactive constituent component, and in addition, can have a constituent component derived from a (meth)acrylic compound (M) described later that forms a (meth)acrylic acid, a constituent component derived from a macromonomer (MM) described later.

[0219] The content of the component derived from the vinyl monomer is not particularly limited and can be appropriately selected in consideration of solubility in the dispersion medium and the like, for example, can be set within the following range in 100 mass% of all components.

[0220] The content of the component derived from the vinyl monomer is not particularly limited and can be appropriately selected in consideration of solubility in the dispersion medium and the like, for example, can be set within the following range in 100 mass% of all components.

[0221] The content of the component derived from the vinyl monomer is not particularly limited and can be appropriately selected in consideration of solubility in the dispersion medium and the like, for example, can be set within the following range in 100 mass% of all components.

[0222] The content of the component derived from the vinyl monomer is not particularly limited and can be appropriately selected in consideration of solubility in the dispersion medium and the like, for example, can be set within the following range in 100 mass% of all components.

[0223] The content of the component derived from the (meth)acrylic compound (M) is preferably the same as in the (meth)acrylic polymer.

[0224] When other components are contained, the content thereof can be appropriately determined.

[0225] The (meth)acrylic polymer used as the dissolving polymer is not particularly limited, and is preferably, for example, a polymer obtained by (co)polymerizing at least one of the above-described (meth)acrylic compound (M). Further, a (meth)acrylic polymer composed of a copolymer of the (meth)acrylic compound (M) and another polymerizable compound (N) is also preferable. The other polymerizable compound (N) is not particularly limited, and examples include the above-described vinyl compound. The (meth)acrylic compound can be exemplified by, for example, a polymer containing 50% by mass or more of a component derived from the (meth)acrylic compound (M), for example, a polymer containing a component derived from a monomer having a low molecular weight (not having a polymer chain) and not containing a component derived from a macromonomer having a polymer chain (MM), and a polymer containing a component derived from a macromonomer (MM). The macromonomer is not particularly limited, and examples include a (meth)acrylic monomer or a vinyl monomer having a polymer chain with a number average molecular weight of 1,000 or more, and specifically, the macromonomer (X) described in Patent Document 1. As the (meth)acrylic polymer, for example, the polymer described in Japanese Patent No. 6295332 can be exemplified.

[0226] The content of the component in the (meth)acrylic polymer is not particularly limited, and can be appropriately selected, taking into account the solubility in the dispersion medium and the like, and can be set in the following range, for example, in 100% by mass of all the components.

[0227] The content of the component derived from the (meth)acrylic compound (M) in the (meth)acrylic polymer is not particularly limited, and can be set to 100% by mass, and is preferably 5 to 90% by mass, more preferably 10 to 80% by mass, further preferably 20 to 70% by mass, and particularly preferably more than 50% by mass and 70% by mass or less, from the viewpoint of the dispersing properties, and the resistance and cycle properties. Further, the content of the component derived from the (meth)acrylic ester compound of an aliphatic hydrocarbon having 4 or more carbon atoms in the (meth)acrylic polymer can be appropriately set in consideration of the range of the content of the component derived from the above-described (meth)acrylic compound (M). For example, it is preferably 20 to 98% by mass, more preferably 50 to 95% by mass, and particularly preferably 60 to 90% by mass.

[0228] The content of the reactive constituent in the (meth)acrylic acid can be appropriately determined taking into account the content of the (meth)acrylic compound (M) described above or the vinyl monomer described later. For example, from the viewpoint of dispersibility, and resistance and cycle characteristics, in the dissoluble polymers C1-I and C1-II, 0.1 to 50% by mass, more preferably 1 to 40% by mass, and particularly preferably 2 to 35% by mass, respectively, is preferred. On the other hand, in the dissoluble polymer C2, from the same viewpoint, 0.1 to 50% by mass, more preferably 5 to 40% by mass, and particularly preferably 10 to 35% by mass, is preferred. The content of the constituent derived from the polymerizable compound (N) in the (meth)acrylic acid is not particularly limited, and is preferably 1% by mass or more and less than 50% by mass, more preferably 5% by mass or more and 50% by mass or less, and particularly preferably 20% by mass or more and less than 50% by mass. The content of the constituent derived from the styrene compound in the (meth)acrylic acid in the polymerizable compound (N) can be appropriately set taking into account the range of the content of the constituent derived from the polymerizable compound (N) described above, and is preferably 1% by mass or more and less than 50% by mass, more preferably 10 to 45% by mass, and particularly preferably 20 to 40% by mass, from the viewpoint of resistance and cycle characteristics. Further, the content of the constituent derived from the unsaturated carboxylic anhydride in the (meth)acrylic polymer in the vinyl monomer can be appropriately set taking into account the range of the content of the constituent derived from the vinyl monomer described above, but is preferably 0.1 to 10% by mass, more preferably 0.3 to 7% by mass, and particularly preferably 2 to 5% by mass, from the viewpoint of resistance and cycle characteristics.

[0229] The content of the constituent (MM) is preferably 5 to 70% by mass, and more preferably 20 to 50% by mass.

[0230] When other constituents are contained, the content thereof can be appropriately determined.

[0231] The hydrocarbon polymer used as the dissolving polymer is not particularly limited, and (co)polymerized polymers of α-olefins can be generally mentioned as examples. Specifically, polyethylene, polypropylene, natural rubber, polybutadiene, polyisoprene, polystyrene, polystyrene butadiene copolymer, styrene-based thermoplastic elastomer, polybutene, acrylonitrile butadiene copolymer, or hydrogenated (hydrogenated) polymers thereof can be mentioned. The styrene-based thermoplastic elastomer or hydrogenated product thereof is not particularly limited, and styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), hydrogenated SIS, styrene-isobutylene-styrene block copolymer (SIBS), 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 each of the above block copolymers, and the like can be mentioned as examples.

[0232] The content of the constituent component in the hydrocarbon polymer is not particularly limited, and can be appropriately selected in consideration of solubility in the dispersion medium or the like.

[0233] When the hydrocarbon polymer has a constituent component derived from a styrene compound, the content of the constituent component in the hydrocarbon polymer is preferably 1 to 70% by mass, more preferably 10 to 50% by mass, and particularly preferably 20 to 40% by mass from the viewpoint of electrical resistance and cycle characteristics.

[0234] Also, when the hydrocarbon polymer has a constituent component derived from an unsaturated carboxylic anhydride, the content of the constituent component in the hydrocarbon polymer is preferably 0.1 to 20% by mass, more preferably 0.2 to 15% by mass, and particularly preferably 0.3 to 10% by mass from the viewpoint of electrical resistance and cycle characteristics.

[0235] As the fluorine polymer preferably used as the dissolving polymer, (co)polymerized polymers of fluorine-substituted polymerizable compounds or the like can be mentioned. Specifically, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), a copolymer of polyvinylidene fluoride and hexafluoropropylene (PVdF-HFP), a copolymer of polyvinylidene fluoride and hexafluoropropylene and tetrafluoroethylene (PVdF-HFP-TFE) can be mentioned.

[0236] The content of the constituent component in the fluorine polymer is not particularly limited, and can be appropriately selected in consideration of solubility in the dispersion medium or the like.

[0237] For example, in PVdF-HFP, the copolymerization ratio of PVdF to HFP [PVdF:HFP] (mass ratio) is not particularly limited, but is preferably 9:1 to 4:6, and more preferably 9:1 to 7:3 from the viewpoint of adhesion. Furthermore, in PVdF-HFP-TFE, the copolymerization ratio of PVdF to HFP to TFE [PVdF:HFP:TFE] (mass ratio) is not particularly limited, but is preferably 20 to 60:10 to 40:5 to 30.

[0238] When the fluoropolymer has a component derived from (meth)acrylic acid compound (M), the content of this component in the fluoropolymer is preferably 0.1 to 40% by mass, more preferably 1 to 30% by mass, and especially preferably 3 to 20% by mass, from the viewpoint of electrical resistance and cycling characteristics.

[0239] Soluble polymers may have substituents. There are no particular limitations on the substituents, but groups selected from substituent Z below are preferred.

[0240] Polymer adhesives composed of soluble polymers have the function of binding solid particles as described above. Therefore, soluble polymers may not have substituents (such as polar groups such as carboxyl groups) that exhibit adsorption properties to solid particles.

[0241] -Substituent Z-

[0242] alkyl (preferably, alkyl having 1 to 20 carbon atoms, for example, methyl, ethyl, isopropyl, t-butyl, amyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.), alkenyl (preferably, alkenyl having 2 to 20 carbon atoms, for example, vinyl, allyl, oleyl, etc.), alkynyl (preferably, alkynyl having 2 to 20 carbon atoms, for example, ethynyl, butynyl, phenylethynyl, etc.), cycloalkyl (preferably, cycloalkyl having 3 to 20 carbon atoms, for example, cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc. In the present specification, when referred to as alkyl, it generally means including cycloalkyl, but is separately described here.), aryl (preferably, aryl having 6 to 26 carbon atoms, for example, phenyl, 1-naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methylphenyl, etc.), aralkyl (preferably, aralkyl having 7 to 23 carbon atoms, for example, benzyl, phenylethyl, etc.), heterocyclic group (preferably, heterocyclic group having 2 to 20 carbon atoms, more preferably, 5- or 6-membered ring having at least one oxygen atom, sulfur atom, nitrogen atom. The heterocyclic group includes aromatic heterocyclic group and aliphatic heterocyclic group. For example, tetrahydropyranyl, tetrahydrofuranyl, 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-oxazolyl, pyrrolidinonyl, etc.), alkoxy (preferably, alkoxy having 1 to 20 carbon atoms, for example, methoxy, ethoxy, isopropoxy, benzyloxy, etc.), aryloxy (preferably, aryloxy having 6 to 26 carbon atoms, for example, phenoxy, 1-naphthyloxy, 3-methylphenoxy, 4-methoxyphenoxy, etc. In the present specification, when referred to as aryloxy, it means including aroyloxy.), heterocyclic-oxy (a group in which -O- is bonded to the above heterocyclic group), alkoxycarbonyl (preferably, alkoxycarbonyl having 2 to 20 carbon atoms, for example, ethoxycarbonyl, 2-ethylhexyloxycarbonyl, dodecyloxycarbonyl, etc.), aryloxycarbonyl (preferably, aryloxycarbonyl having 6 to 26 carbon atoms, for example, phenoxycarbonyl, 1-naphthyloxycarbonyl, 3-methylphenoxycarbonyl, 4-methoxyphenoxycarbonyl, etc.), heterocyclic-oxycarbonyl (a group in which -O-CO- is bonded to the above heterocyclic group), amino (preferably, amino including amino having 0 to 20 carbon atoms, alkylamino, arylamino, for example, amino (-NH2), N,N-dimethylamino, N,N-diethylamino, N-ethylamino, anilino, etc.), sulfamoyl (preferably, sulfamoyl having 0 to 20 carbon atoms, for example, N,N-dimethylsulfamoyl, N-phenylsulfamoyl, etc.), acyl (including alkylcarbonyl, alkenylcarbonyl, alkynylcarbonyl, arylcarbonyl, heterocyclic carbonyl, preferably acyl having 1 to 20 carbon atoms, for example, acetyl, propionyl, butyryl, octanoyl, hexadecanoyl, propenoyl, methyipropenoyl, crotonoyl, benzoyl, naphthoyl, nicotinoyl, etc.), acyloxy (including alkylcarbonyloxy, alkenylcarbonyloxy, alkynylcarbonyloxy, arylcarbonyloxy, heterocyclic carbonyloxy, preferably acyloxy having 1 to 20 carbon atoms, for example, acetyloxy, propionyloxy, butyryloxy, octanoyloxy, hexadecanoyloxy, propenoyloxy, methyipropenoyloxy, crotonoyloxy, benzoyloxy, naphthoyloxy, nicotinoyloxy, etc.), aryloyloxy (preferably aryloyloxy having 7 to 23 carbon atoms, for example, benzoyloxy, etc.), carbamoyl (preferably carbamoyl having 1 to 20 carbon atoms, for example, N,N-dimethylcarbamoyl, N-phenylcarbamoyl, etc.), acylamino (preferably acylamino having 1 to 20 carbon atoms, for example, acetylamino, benzoylamino, etc.), alkylthio (preferably alkylthio having 1 to 20 carbon atoms, for example, methylthio, ethylthio, isopropylthio, benzylthio, etc.), arylthio (preferably arylthio having 6 to 26 carbon atoms, for example, phenylthio, 1-naphthylthio, 3-methylphenylthio, 4-methoxyphenylthio, etc.), heterocyclic thio (-S- group bonded to the above heterocyclic group), alkylsulfonyl (preferably alkylsulfonyl having 1 to 20 carbon atoms, for example, methylsulfonyl, ethylsulfonyl, etc.), arylsulfonyl (preferably arylsulfonyl having 6 to 22 carbon atoms, for example, phenylsulfonyl, etc.), alkylsilyl (preferably alkylsilyl having 1 to 20 carbon atoms, for example, monomethylsilyl, dimethylsilyl, trimethylsilyl, triethylsilyl, etc.), arylsilyl (preferably arylsilyl having 6 to 42 carbon atoms, for example, triphenylsilyl, etc.), alkoxy silyl (preferably alkoxy silyl having 1 to 20 carbon atoms, for example, monomethoxysilyl, dimethoxysilyl, trimethoxysilyl, triethoxysilyl, etc.), aryloxy silyl (preferably aryloxy silyl having 6 to 42 carbon atoms, for example, triphenyloxy silyl, etc.), phosphoryl (preferably phosphoryl having 0 to 20 carbon atoms, for example, -OP(=O)(R P )2), phosphinoyl (preferably phosphinoyl having 0 to 20 carbon atoms, for example, -P(=O)(R P )2), phosphinyl (preferably phosphinyl having 0 to 20 carbon atoms, for example, -P(R P )2), phosphonic acid (preferably phosphonic acid having 0 to 20 carbon atoms, for example, -PO(OR P )2), sulfo (sulfonic acid), carboxy, hydroxy, sulfanyl, cyano, halogen (for example, fluorine, chlorine, bromine, iodine, etc.).R Phydrogen atom or a substituent (preferably a group selected from substituent Z).

[0243] Further, each of the groups listed in these substituents Z can be further substituted with the above-mentioned substituent Z.

[0244] The above-mentioned alkyl group, alkylene group, alkenyl group, alkenylene group, alkynyl group and / or alkynylene group, etc. can be either cyclic or acyclic, and can be either straight-chain or branched.

[0245] (Properties or characteristics of the dissolvable polymer, etc.)

[0246] The dissolvable polymer preferably has the following properties or characteristics, etc.

[0247] The moisture concentration of the dissolvable polymer is preferably 100 ppm or less (on a mass basis). Further, the dissolvable polymer can be crystallized and dried, or a solution of the dissolvable polymer can be used directly.

[0248] The dissolvable polymer is preferably amorphous. In the present application, a polymer is "amorphous" typically means that no endothermic peak due to crystal melting is observed when measured at the glass transition temperature.

[0249] The dissolvable polymer can be either a non-crosslinked polymer or a crosslinked polymer. Further, when the crosslinking of the polymer is performed by heating or the application of voltage, the molecular weight can become greater than the above-mentioned molecular weight. Preferably, the mass average molecular weight of the polymer is in the range described later at the time of the start of use of the all-solid-state secondary battery.

[0250] The mass average molecular weight of the dissolvable polymer is not particularly limited. For example, it is preferably 15,000 or more, more preferably 30,000 or more, and further preferably 50,000 or more. As an upper limit, it is practically 5,000,000 or less, preferably 4,000,000 or less, more preferably 3,000,000 or less, further preferably 500,000 or less, and can also be set to 300,000 or less, and furthermore can also be set to 100,000 or less.

[0251] Measurement of molecular weight

[0252] In the present application, the molecular weight of the polymer, polymer chain and macromer means the mass average molecular weight or the number average molecular weight converted to standard polystyrene obtained by gel permeation chromatography (GPC), unless otherwise specified. As a method for measuring the same, basically, the method of the following condition 1 or condition 2 (preferably) can be mentioned. Among these, a suitable eluent is appropriately selected according to the kind of the polymer or macromer and used.

[0253] (Condition 1)

[0254] Column: TOSOH TSKgel Super AWM-H (trade name, manufactured by TOSOH CORPORATION) connected with two

[0255] Carrier: 10 mM LiBr / N-methylpyrrolidone

[0256] Measurement temperature: 40°C

[0257] Carrier flow rate: 1.0 ml / min

[0258] Sample concentration: 0.1 mass%

[0259] Detector: RI (refractive index) detector

[0260] (Condition 2)

[0261] Column: Column in which TOSOH TSKgel Super HZM-H, TOSOH TSKgel Super HZ4000, and TOSOH TSKgel Super HZ2000 (all trade names, manufactured by Tosoh Corporation) were connected.

[0262] Carrier: Tetrahydrofuran

[0263] Measurement temperature: 40°C

[0264] Carrier flow rate: 1.0 ml / min

[0265] Sample concentration: 0.1 mass%

[0266] Detector: RI (refractive index) detector

[0267] The raw material compound (monomer) of the dissolvable polymer can be selected by a known method, and the dissolvable polymer can be synthesized by polymerizing the raw material compound. The method of incorporating a functional group or a partial structure is not particularly limited, and for example, a method of copolymerizing a compound having a functional group or a partial structure, a method of using a polymerization initiator or a chain transfer agent having (generating) a functional group or a partial structure, a method of utilizing a high molecular reaction, and the like can be cited.

[0268] Specific examples of the dissolvable polymer can include the polymers shown in the examples, but the present application is not limited to these.

[0269] The inorganic solid electrolyte-containing composition of the present application can contain components constituting one kind of polymer binder, or can contain components constituting a plurality of kinds of polymer binders.

[0270] The content of the components constituting the polymer binder in the inorganic solid electrolyte-containing composition is as described above, and the content of the polymer binder in the inorganic solid electrolyte-containing composition, assuming that the components form a polymer binder, is preferably 0.1 to 10.0% by mass, more preferably 0.2 to 5.0% by mass, and further preferably 0.3 to 4.0% by mass, relative to the total mass of the composition, from the viewpoint of dispersion properties, resistance reduction, and cycle properties. On the other hand, in 100% by mass of the solid components, the content is preferably 0.1 to 10.0% by mass, more preferably 0.3 to 8% by mass, and further preferably 0.5 to 7% by mass, for the same reasons.

[0271] In the present application, the mass ratio of the total content of the inorganic solid electrolyte and the active material relative to the content of the polymer binder described above [(mass of the inorganic solid electrolyte + mass of the active material) / mass of the polymer binder] is preferably in the range of 1,000 to 1, in 100% by mass of the solid components. Further, the ratio is more preferably 500 to 2, and further preferably 100 to 10.

[0272] <Dispersion medium>

[0273] The inorganic solid electrolyte-containing composition of the present application preferably contains a dispersion medium that disperses the above-described components.

[0274] As the dispersion medium, any organic compound that exhibits a liquid state in the use environment can be used, and various organic solvents such as alcohol compounds, ether compounds, amide compounds, amine compounds, ketone compounds, aromatic compounds, aliphatic compounds, nitrile compounds, and ester compounds can be mentioned, specifically.

[0275] The dispersion medium can be a nonpolar dispersion medium (hydrophobic dispersion medium) or a polar dispersion medium (hydrophilic dispersion medium), and from the viewpoint of being able to exhibit excellent dispersion properties, a nonpolar dispersion medium is preferred. As the nonpolar dispersion medium, a property of having low affinity for water is generally meant, but in the present application, for example, ester compounds, ketone compounds, ether compounds, aromatic compounds, and aliphatic compounds can be mentioned, and among these, ketone compounds, aliphatic compounds, and ester compounds can be preferred.

[0276] 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, and 1,4-butanediol can be mentioned.

[0277] As ether compounds, for example, there can be mentioned alkylene glycols (diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, etc.), alkylene glycol monoalkyl ethers (ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, diethylene glycol monobutyl ether, etc.), alkylene glycol dialkyl ethers (ethylene glycol dimethyl ether, etc.), dialkyl ethers (dimethyl ether, diethyl ether, diisopropyl ether, dibutyl ether, etc.), cyclic ethers (tetrahydrofuran, dioxane (each isomer of 1,2-, 1,3-, and 1,4-), etc.).

[0278] As amide compounds, for example, there can be mentioned 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.

[0279] As amine compounds, for example, there can be mentioned triethylamine, diisopropylethylamine, tri-n-butylamine, etc.

[0280] As ketone compounds, for example, there can be mentioned acetone, methyl ethyl ketone, methyl isobutyl ketone (MIBK), cyclopentanone, cyclohexanone, cycloheptanone, dipropyl ketone, dibutyl ketone, diisopropyl ketone, diisobutyl ketone (DIBK), isobutyl propyl ketone, sec-butyl propyl ketone, amyl propyl ketone, butyl propyl ketone, etc.

[0281] As aromatic compounds, for example, there can be mentioned benzene, toluene, xylene, etc.

[0282] As aliphatic compounds, for example, there can be mentioned hexane, heptane, octane, nonane, decane, dodecane, cyclohexane, methylcyclohexane, ethylcyclohexane, cycloheptane, cyclooctane, decalin, paraffin, gasoline, naphtha, kerosene, light oil, etc.

[0283] As nitrile compounds, for example, there can be mentioned acetonitrile, propionitrile, isobutyronitrile, etc.

[0284] As ester compounds, for example, there can be mentioned 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.

[0285] In the present application, among them, ether compounds, ketone compounds, aromatic compounds, aliphatic compounds, ester compounds are preferred, and ester compounds, ketone compounds, or ether compounds are more preferred.

[0286] There is no particular limitation on the number of carbon atoms in the compound constituting the dispersion medium, but it is preferably 2 to 30, more preferably 4 to 20, even more preferably 6 to 15, and especially preferably 7 to 12.

[0287] From the perspective of dispersion characteristics, the SP value (unit: MPa) of the dispersion medium 1 / 2 The preferred value is 10.0 to 30.0, more preferably 15.0 to 25.0, and even more preferably 17.0 to 20.0.

[0288] The SP value of the dispersion medium is set to be the SP value calculated by the Hoy method below, converted to MPa. 1 / 2 The SP value is obtained as follows. When the inorganic solid electrolyte composition contains two or more dispersion media, the SP value of the dispersion media refers to the SP value of the entire dispersion media, and is set as the sum of the products of the SP value of each dispersion media and its mass fraction. Specifically, except that the SP value of each dispersion media is used instead of the SP value of the constituent components, it is calculated in the same way as the SP value of the polymer described above.

[0289] The following shows the SP values ​​(units omitted) of the dispersion medium.

[0290] 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), isobutyl ethyl ether (15.3), N-methylpyrrolidone (NMP, SP value: 25.4)

[0291] The SP value of the dispersion medium is the value obtained by the Hoy method (refer to HL Hoy JOURNAL OF PAINTTECHNOLOGY Vol.42, No.541, 1970, 76-118, and POLYMER HANDBOOK 4). th Chapter 59, VII, page 686, Tables 5 and 6, and the following expressions in Table 6) conversion (e.g., 1 cal 1 / 2 cm -3 / 2 ≈2.05J 1 / 2 cm -3 / 2 ≈2.05MPa 1 / 2 SP value (MPa) 1 / 2 The value obtained is ).

[0292] [Formula 1]

[0293]

[0294] In the formula, δt represents SP value. F t is molar attraction function (J x cm 3 / mol) represented by the following formula. V is molar volume (cm / 2 / mol) represented by the following formula. 3 represented by the following formula.

[0295] F t =∑n i F t，i V=∑n i V i

[0296]

[0297] In the above formula, F t，i represents molar attraction function of each structural unit, V i represents molar volume of each structural unit, Δ (p ) T，i represents correction value of each structural unit, n i represents number of each structural unit.

[0298] The CLogP value calculated by the above method is preferably -2.5 or more, more preferably -0.5 or more, further preferably 2.0 or more, and particularly preferably 2.6 or more from the viewpoint of dispersion properties of the dispersion medium. The upper limit is not particularly limited, and is practically 10.0 or less, and preferably 5.0 or less.

[0299] The CLogP value of the dispersion medium is shown in parentheses.

[0300] Toluene (2.5), xylene (3.12), hexane (3.9), heptane (Hep, 4.4), octane (4.9), cyclohexane (3.4), cyclooctane (4.5), decalin (4.8), diisobutyl ketone (3.0), dibutyl ether (2.57), butyl butyrate (2.8), tributylamine (4.8), methyl isobutyl ketone (1.31), ethylcyclohexane (3.4)

[0301] The boiling point of the dispersion medium at normal pressure (1 atm) is preferably 50°C or more, and more preferably 70°C or more. The upper limit is preferably 250°C or less, and further preferably 220°C or less.

[0302] The inorganic solid electrolyte-containing composition of the present application can contain at least one dispersion medium, and can contain two or more.

[0303] ​In the present application, the content of the dispersion medium in the inorganic solid electrolyte-containing composition is not particularly limited and can be appropriately set. For example, in the inorganic solid electrolyte-containing composition, the content is preferably 20 to 80 mass%, more preferably 30 to 70 mass%, and particularly preferably 40 to 60 mass%.

[0304] <Active material>

[0305] The inorganic solid electrolyte-containing composition of the present application 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, the following will be described, and examples of the active material can include positive electrode active materials and negative electrode active materials.

[0306] In the present application, the inorganic solid electrolyte-containing composition containing an active material (positive electrode active material or negative electrode active material) is sometimes referred to as an electrode composition (positive electrode composition or negative electrode composition).

[0307] (Positive electrode active material)

[0308] 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 the material is a material having the above-described characteristics, the material is not particularly limited, and can be a transition metal oxide or an organic substance, sulfur, or the like capable of being complexed with Li.

[0309] 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 of Co, Ni, Fe, Mn, Cu, and V. Furthermore, an element M b of the periodic table other than lithium, Group 1 (Ia) elements, Group 2 (Ha) elements, Al, Ga, In, Ge, Sn, Pb, Sb, Bi, Si, P, and B. As the mixing amount, the amount (100 mol%) of the transition metal element M a is preferably 0 to 30 mol%. More preferably, the molar ratio of Li / M a is synthesized in such a manner that the molar ratio becomes 0.3 to 2.2.

[0310] Specific examples of the transition metal oxide can include (MA) a transition metal oxide having a layered rock salt type structure, (MB) a transition metal oxide having a spinel type structure, (MC) a lithium-containing transition metal phosphoric acid compound, (MD) a lithium-containing transition metal halogenated phosphoric acid compound, and (ME) a lithium-containing transition metal silicic acid compound, and the like.

[0311] Specific examples of transition metal oxides (MA) with layered rock salt-type structures include LiCoO2 (lithium cobalt oxide [LCO]), LiNi2O2 (lithium nickel oxide), and LiNi 0.85 Co 0.10 Al 0.05 O2 (lithium nickel cobalt aluminum oxide [NCA]), LiNi 1 / 3 Co 1 / 3 Mn 1 / 3O2 (lithium nickel manganese cobalt oxide [NMC]) and LiNi 0.5 Mn 0.5 O2 (lithium manganese nickel oxide).

[0312] Specific examples of transition metal oxides (MB) with spinel-type structures include LiMn2O4 (LMO), LiCoMnO4, Li2FeMn3O8, Li2CuMn3O8, Li2CrMn3O8, and Li2NiMn3O8.

[0313] Examples of lithium-containing transition metal phosphates (MC) include 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).

[0314] Examples of lithium-containing transition metal halophosphates (MD) include, for example, iron fluorophosphates such as Li2FePO4F, manganese fluorophosphates such as Li2MnPO4F, and cobalt fluorophosphates such as Li2CoPO4F.

[0315] Examples of lithium-containing transition metal silicate compounds include, for example, Li2FeSiO4, Li2MnSiO4, and Li2CoSiO4.

[0316] In this invention, (MA) is preferably a transition metal oxide having a layered rock salt structure, and more preferably LCO or NMC.

[0317] The shape of the positive electrode active material is not particularly limited, but particulate form 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 0.1–50 μm. The particle size of the positive electrode active material can be measured in the same manner as the particle size of the aforementioned inorganic solid electrolyte. To achieve the desired particle size, a conventional pulverizer or classifier is used. For example, a mortar, ball mill, sand mill, vibratory ball mill, satellite ball mill, planetary ball mill, and rotary airflow jet mill or sieve can be suitably used. During pulverization, wet pulverization with a dispersion medium such as water or methanol can also be appropriately performed. To achieve the desired particle size, classification is preferred. Classification is not particularly limited and can be performed using sieves, air classifiers, etc. Both dry and wet classification can be used.

[0318] Positive active materials obtained by sintering can also be used after being cleaned with water, acidic aqueous solutions, alkaline aqueous solutions, and organic solvents.

[0319] One type of positive electrode active material can be used alone, or two or more types can be used in combination.

[0320] When a positive electrode active material layer is formed, the per unit area (cm²) of the positive electrode active material layer... 2 There is no particular limitation on the mass (mg) (weight per unit area) of the positive electrode active material. It can be appropriately determined according to the designed battery capacity, for example, it can be set to 1 to 100 mg / cm³. 2 .

[0321] The content of the positive electrode active material in the inorganic solid electrolyte composition is not particularly limited, but it is preferably 10-97% by mass, more preferably 30-95% by mass, further preferably 40-93% by mass, and especially preferably 50-90% by mass in 100% by mass of the solid component.

[0322] (Negative electrode active material)

[0323] The negative 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. The material is not particularly limited as long as it is a material having the above-described characteristics, and examples include carbonaceous materials, metal oxides, metal complex oxides, lithium monomers, lithium alloys, negative active materials capable of alloying with lithium (capable of alloying), and the like. Among them, from the viewpoint of reliability, it is preferable to use a carbonaceous material, a metal complex oxide, or a lithium monomer. From the viewpoint of enabling the large capacity of the all-solid-state secondary battery, it is preferable to be an active material capable of alloying with lithium. Since the constitution layer formed of the inorganic solid electrolyte-containing composition of the present application can maintain a firm bonding state of the solid particles to each other, a negative active material capable of alloying with lithium can be used as the negative active material. Thereby, the capacity of the all-solid-state secondary battery can be increased and the life of the battery can be extended.

[0324] The carbonaceous material used as the negative active material refers to a material consisting essentially of carbon. For example, carbon black such as petroleum pitch, acetylene black (AB), and the like, graphite (natural graphite, vapor-grown graphite, and the like, artificial graphite, and the like), and various synthetic resins such as PAN (polyacrylonitrile)-based resins or furfuryl alcohol resins, and the like, which are fired, can be given. Furthermore, 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, glassy carbon fibers, and activated carbon fibers, and the like, mesophase microspheres, graphite whiskers, and platelet-shaped graphite, and the like, can also be given.

[0325] These carbonaceous materials are classified into a difficultly graphitizable carbonaceous material (also referred to as hard carbon) and a graphite-based carbonaceous material by the degree of graphitization. Furthermore, the carbonaceous material preferably has an interlayer spacing or density, a crystallite size described in Japanese Patent Application Publication No. 62-22066, Japanese Patent Application Publication No. 2-6856, Japanese Patent Application Publication No. 3-45473. The carbonaceous material need not be a single material, and a mixture of natural graphite and artificial graphite described in Japanese Patent Application Publication No. 5-90844, graphite having a coating layer described in Japanese Patent Application Publication No. 6-4516, and the like, can also be used.

[0326] As the carbonaceous material, it is preferable to use hard carbon or graphite, and more preferably to use graphite.

[0327] As the oxide of a metal or semi-metal element which is applicable as a negative electrode active material, there is no particular limitation as long as it is an oxide capable of occluding and releasing lithium, and examples thereof include an oxide of a metal element (metal oxide), a composite oxide of a metal element, or a composite oxide of a metal element and a semi-metal element (collectively referred to as a metal composite oxide), and an oxide of a semi-metal element (semi-metal oxide). As these oxides, an amorphous oxide is preferable, and further, a chalcogenide which is a reaction product of a metal element and an element of Group 16 of the periodic table is also preferable. In the present application, a semi-metal element refers to an element exhibiting a property intermediate between a metal element and a non-semi-metal element, and generally includes six elements of boron, silicon, germanium, arsenic, antimony, and tellurium, and further includes three elements of selenium, polonium, and astatine. Further, amorphous refers to a material having a broad scattering band with a peak in a region of 20° to 40° in terms of 2θ value by X-ray diffraction using CuKα rays, and can also have a crystalline diffraction line. The intensity of the strongest diffraction line of the crystalline diffraction line appearing in a region of 40° to 70° in terms of 2θ value is preferably 100 times or less, more preferably 5 times or less, of the intensity of the diffraction line of the peak of the broad scattering band appearing in a region of 20° to 40° in terms of 2θ value, and particularly preferably, the material does not have a crystalline diffraction line.

[0328] Among the compound group including the above-described amorphous oxide and chalcogenide, an amorphous oxide of a semi-metal element or the above-described chalcogenide is further preferable, and particularly preferably, a (composite) oxide or chalcogenide containing a single one or a combination of two or more of elements selected from the group consisting of Group 13 (IIIB) to Group 15 (VB) of the periodic table (e.g., Al, Ga, Si, Sn, Ge, Pb, Sb, and Bi). As specific examples of the preferable amorphous oxide and chalcogenide, for example, Ga2O3, GeO, PbO, PbO2, Pb2O3, Pb2O4, Pb3O4, Sb2O3, Sb2O4, Sb2O8Bi2O3, Sb2O8Si2O3, Sb2O5, Bi2O3, Bi2O4, GeS, PbS, PbS2, Sb2S3, or Sb2S5 can be preferable.

[0329] As the negative electrode active material which can be used together with the amorphous oxide centered on Sn, Si, and Ge, a carbonaceous material capable of occluding and / or releasing lithium ions or lithium metal, a lithium monomer, a lithium alloy, and a negative electrode active material capable of alloying with lithium can be preferable.

[0330] From the viewpoint of high current density charge-discharge characteristics, the oxide of a metal or semi-metal element, especially the metal (composite) oxide and the above-mentioned chalcogenide are preferably composed of at least one of titanium and lithium. As the metal composite oxide containing lithium (lithium composite metal oxide), for example, lithium oxide composite oxide of the above-mentioned metal (composite) oxide or the above-mentioned chalcogenide can be cited, and more specifically, Li2SnO2 can be cited.

[0331] The negative electrode active material, for example, metal oxide is also preferably selected to contain titanium element (titanium oxide). Specifically, since Li4Ti5O 12 (Lithium titanate [LTO]) has a small volume change when adsorbing and desorbing lithium ions, and thus has excellent rapid charge-discharge characteristics, and is preferable in terms of both suppressing degradation of the electrode and improving the life of the lithium ion secondary battery.

[0332] The lithium alloy as the negative electrode active material is not particularly limited as long as it is an alloy generally used as a negative electrode active material for a secondary battery, and for example, a lithium-aluminum alloy in which lithium is the base metal and 10 mass% of aluminum is added can be cited.

[0333] The negative electrode active material capable of alloying with lithium is not particularly limited as long as it is a negative electrode active material generally used for a secondary battery. Such an active material has a large expansion and contraction due to charge and discharge of the all-solid-state secondary battery, and accelerates the decrease in cycle characteristics, but the inorganic solid electrolyte-containing composition of the present application contains a polymer binder formed from the components constituting the above-mentioned polymer binder, and thus can suppress the decrease in cycle characteristics. As such an active material, a (negative electrode) active material (alloy, etc.) having silicon element or tin element, each metal such as Al and In, and preferably a negative electrode active material having silicon element capable of achieving higher battery capacity (active material containing silicon element) can be cited, and more preferably an active material containing silicon element having a content of 50 mol% or more of all constituent elements.

[0334] Generally, the negative electrode containing such a negative electrode active material (for example, Si negative electrode containing an active material containing silicon element, Sn negative electrode containing an active material having tin element, etc.) can absorb more Li ions than the carbon negative electrode (graphite and acetylene black, etc.). That is, the amount of occlusion of Li ions per unit mass increases. Therefore, the battery capacity (energy density) can be increased. As a result, it has an advantage that the battery driving time can be extended.

[0335] As the active material containing silicon element, for example, there can be mentioned silicon materials such as Si, SiOx (0 < x < 1), and alloys (for example, LaSi2, VSi2, La-Si, Gd-Si, Ni-Si) or structured active materials (for example, LaSi2 / Si) containing titanium, vanadium, chromium, manganese, nickel, copper, lanthanum, and the like, and further, active materials containing silicon element and tin element such as SnSiO3, SnSiS3, and the like. In addition, SiOx can be used as a negative electrode active material (semimetal oxide) by itself, and Si is generated by operation of the all-solid secondary battery, and thus can be used as a negative electrode active material (precursor) capable of alloying with lithium.

[0336] As the negative electrode active material having tin element, for example, there can be mentioned Sn, SnO, SnO2, SnS, SnS2, and the above-mentioned active materials containing silicon element and tin element, and the like. Further, there can be mentioned a complex oxide with lithium oxide, for example, Li2SnO2.

[0337] In the present application, 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, it is preferable to be a negative electrode active material capable of alloying with lithium, and more preferably, the above-mentioned silicon material or silicon-containing alloy (alloy containing silicon element), and further preferably, a silicon (Si) or silicon-containing alloy.

[0338] As the measurement method, it is possible to calculate the chemical formula of the compound obtained by the above-mentioned calcination method from the mass difference of the powder before and after calcination by inductively coupled plasma (ICP) emission spectroscopy as a simple method.

[0339] The shape of the negative electrode active material is not particularly limited, and it is preferable to be particulate. The volume average particle diameter of the negative electrode active material is not particularly limited, and it is preferable to be 0.1 to 60 μm. The volume average particle diameter of the negative electrode active material particle can be measured in the same manner as the particle diameter of the above-mentioned inorganic solid electrolyte. In order to set to a prescribed particle diameter, a general pulverizer or classifier is used in the same manner as the positive electrode active material.

[0340] The above-mentioned negative electrode active material can be used alone in one kind, or two or more kinds in combination.

[0341] In the case of forming the negative electrode active material layer, the mass (mg) of the negative electrode active material per unit area (cm 2 ) of the negative electrode active material layer (unit area weight) is not particularly limited. It can be appropriately determined in accordance with the designed battery capacity, and for example, it can be set to 1 to 100 mg / cm 2 .

[0342] The content of the negative electrode active material in the inorganic solid electrolyte-containing composition is not particularly limited, and is preferably 10 to 90% by mass, more preferably 20 to 85% by mass, further more preferably 30 to 80% by mass, and further more preferably 40 to 75% by mass, in 100% by mass of the solid content.

[0343] In the present application, when the negative electrode active material layer is formed by charging the secondary battery, instead of the above-mentioned negative electrode active material, an ion belonging to a metal of Group 1 or Group 2 of the periodic table generated in the all-solid-state secondary battery can be used. By bonding this ion to an electron to be deposited as a metal, the negative electrode active material layer can be formed.

[0344] (Coating of active material)

[0345] The surface of the positive electrode active material and the negative electrode active material can also be surface-coated with a different metal oxide. As the surface-coating agent, a metal oxide containing Ti, Nb, Ta, W, Zr, Al, Si, or Li, etc. can be given. Specifically, spinel titanium acid, tantalum-based oxide, niobium-based oxide, lithium niobate-based compound, etc. can be given, and specifically, Li4Ti5O12, Li2Ti2O5, LiTaO3, LiNbO3, LiAlO2, Li2ZrO3, Li2WO4, Li2TiO3, Li2B4O7, Li3PO4, Li2MoO4, Li3BO3, LiBO2, Li2CO3, Li2SiO3, SiO2, TiO2, ZrO2, Al2O3, B2O3, etc. can be given. 12

[0346] Further, 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.

[0347] Furthermore, the surface of the particles of the positive electrode active material or the negative electrode active material can be surface-treated with actinic rays or active gas (plasma, etc.) before and after the above-mentioned surface-coating.

[0348] <Conductive aid>

[0349] The inorganic solid electrolyte-containing composition of the present application preferably contains a conductive aid, and for example, the active material containing a silicon atom as the negative electrode active material is preferably used in combination with a conductive aid.

[0350] ​As the conductive aid, there is no particular limitation, and a conductive aid generally known as a conductive aid can be used. For example, it can be graphite such as natural graphite, artificial graphite, acetylene black, Ketjen black, furnace black, amorphous carbon such as needle coke, carbon fiber such as vapor grown carbon fiber or carbon nanotube, carbonaceous material such as graphene or fullerene, or it can be metal powder such as copper or nickel, metal fiber, or conductive polymer such as polyaniline, polypyrrole, polythiophene, polyacetylene, or polyparaphenylene derivative.

[0351] In the present application, in the case where an active material and a conductive aid are used in combination, among the above-described conductive aids, a conductive aid that does not cause intercalation and deintercalation of ions of a metal belonging to Group 1 or Group 2 of the periodic table (preferably Li ions) at the time of charging and discharging of the battery and does not function as an active material is used. Therefore, among the conductive aids, a conductive aid that can function as an active material in the active material layer at the time of charging and discharging of the battery is classified as an active material rather than a conductive aid. Whether or not it functions as an active material at the time of charging and discharging of the battery is determined by the combination with the active material, and is not determined in general.

[0352] The conductive aid can contain one kind, or two or more kinds.

[0353] The shape of the conductive aid is not particularly limited, and is preferably particulate.

[0354] When the inorganic solid electrolyte-containing composition of the present application contains a conductive aid, the content of the conductive aid in the inorganic solid electrolyte-containing composition is preferably 0 to 10 mass% in 100 mass% of the solid content.

[0355] < Lithium salt >

[0356] The inorganic solid electrolyte-containing composition of the present application preferably further contains a lithium salt (supporting electrolyte).

[0357] As the lithium salt, a lithium salt generally used for such a product is preferable, and there is no particular limitation, and for example, it is preferably a lithium salt described in paragraphs 0082 to 0085 of Japanese Patent Application Publication No. 2015-088486.

[0358] When the inorganic solid electrolyte-containing composition of the present application contains a lithium salt, the content of the lithium salt is preferably 0.1 parts by mass or more, and more preferably 5 parts by mass or more, with respect to 100 parts by mass of the solid electrolyte. As the upper limit, it is preferably 50 parts by mass or less, and more preferably 20 parts by mass or less.

[0359] < Dispersant >

[0360] The above solubility polymer also functions as a dispersant in the inorganic solid electrolyte-containing composition of the present application, and therefore a dispersant other than the solubility polymer can not be included. When a dispersant other than the solubility polymer is included in the inorganic solid electrolyte-containing composition, a dispersant generally used for all-solid-state secondary batteries can be appropriately selected and used as the dispersant. Generally, a desired compound among particle adsorption, steric repulsion, and / or electrostatic repulsion is appropriately used.

[0361] <Other additives>

[0362] The inorganic solid electrolyte-containing composition of the present application can appropriately include an ionic liquid, a thickening agent, a crosslinking agent (a substance that performs a crosslinking reaction by radical polymerization, polycondensation, or ring-opening polymerization, etc.), a polymerization initiator (a substance that generates an acid or a radical by heat or light, etc.), an antifoaming agent, a leveling agent, a dehydrating agent, an antioxidant, etc. as other components than the above components. The ionic liquid is a liquid included to further improve the ionic conductivity, and a publicly known liquid can be used without particular limitation. Furthermore, a polymer other than the polymer that forms the above polymer binder can include a binder or the like that is generally used.

[0363] (Preparation of inorganic solid electrolyte-containing composition)

[0364] The inorganic solid electrolyte-containing composition of the present application can be prepared as a mixture, preferably as a slurry, by mixing, for example, an inorganic solid electrolyte, components that constitute a polymer binder, a dispersion medium, preferably a conductive aid, and an appropriate lithium salt, and optional other components, using a publicly known various mixer. In the case of an electrode composition, an active material is further mixed.

[0365] The mixing method is not particularly limited, and the mixing can be performed at once or sequentially. The mixing environment is not particularly limited, and can be, for example, under dry air or under an inert gas. The mixing conditions are not particularly limited, and are preferably conditions under which the components that constitute the polymer binder do not chemically react, and can be appropriately set depending on the kind or combination of the functional groups or partial structures (I) and (II), the content of each component, etc. For example, when the solubility polymer has a blocked isocyanate group as a functional group or partial structure (I), the temperature is set to be lower than the temperature at which the isocyanate group is regenerated (the temperature at which the blocking agent is deprotected).

[0366] [Sheet for all-solid-state secondary battery]

[0367] The sheet for all-solid-state secondary battery of the present application is a sheet-shaped molded body capable of forming a constituent layer of an all-solid-state secondary battery, and includes various modes according to its use. For example, a sheet preferably used for a solid electrolyte layer (also referred to as a solid electrolyte sheet for 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 all-solid-state secondary battery), and the like can be mentioned. In the present application, these various sheets are collectively referred to as a sheet for all-solid-state secondary battery.

[0368] The solid electrolyte sheet for all-solid-state secondary battery of the present application is only required to be a sheet having a solid electrolyte layer, and can be a sheet on which a solid electrolyte layer is formed on a substrate, or a sheet formed of a solid electrolyte layer without a substrate. The solid electrolyte sheet for all-solid-state secondary battery can have other layers in addition to the solid electrolyte layer. As the other layers, for example, a protective layer (release sheet), a current collector, a coating layer, and the like can be mentioned.

[0369] As the solid electrolyte sheet for all-solid-state secondary battery of the present application, for example, a sheet sequentially having a layer composed of the inorganic solid electrolyte composition-containing composition of the present application, a general solid electrolyte layer, and a protective layer on a substrate can be mentioned. The layer thickness of each layer constituting the solid electrolyte sheet for all-solid-state secondary battery is the same as the layer thickness of each layer described in the all-solid-state secondary battery described later.

[0370] The solid electrolyte layer possessed by the solid electrolyte sheet for all-solid-state secondary battery is preferably formed of the inorganic solid electrolyte composition-containing composition of the present application.

[0371] In the film formation process of the inorganic solid electrolyte composition-containing composition of the present application, the dissolving state dissolving polymers C1-I and C1-II and the dissolving polymer C2 undergo chemical reactions as components constituting the polymer binder. The chemical reactions of the dissolving polymers are determined according to the functional groups or partial structures, as described above. With the progress of the chemical reactions, the solubility of the dissolving polymers in the dispersion medium gradually decreases, and the dissolving polymers are preferably solidified or precipitated in a particulate form while maintaining the adsorbed state with the solid particles. Thus, while maintaining the firm adhesion of the solid particles to each other, the entire surface of the solid particles is not coated, and the ion conduction path can be sufficiently constructed. The solid electrolyte layer composed of the inorganic solid electrolyte composition-containing composition preferably contains the polymer binder resulting from the chemical reaction of the dissolving polymer constituting the polymer binder as a particle.

[0372] The constitution layer formed of the inorganic solid electrolyte composition of the present application contains the polymer binder formed of the dissolvable polymer C1-1 and C1-II or the dissolvable polymer C2 as described above, but it is not necessary that the dissolvable polymer contained in the inorganic solid electrolyte composition forms the polymer binder entirely, and it can contain the (residual) dissolvable polymer which has not been subjected to the chemical reaction within the range not impairing the effects of the present application. The content of each component in the constitution layer is not particularly limited, and it is preferable that the meaning is the same as the meaning of the content of each component in the solid component of the inorganic solid electrolyte composition of the present application. Among them, the content of the polymer binder is generally the same as the total content of the dissolvable polymer.

[0373] As the substrate, it is not particularly limited as long as it is a substrate capable of supporting the solid electrolyte layer, and examples thereof include the materials described in the current collector described later, a sheet body (a plate-shaped body) of an organic material, an inorganic material, and the like. As the organic material, various polymers and the like can be given, and specifically, polyethylene terephthalate, polypropylene, polyethylene, cellulose, and the like can be given. As the inorganic material, for example, glass, ceramics, and the like can be given.

[0374] The electrode sheet (also simply referred to as "electrode sheet") of the present application is an electrode sheet having an active material layer, and it can be a sheet in which the active material layer is formed on a substrate (a current collector), or a sheet formed of the active material layer without the substrate. The electrode sheet is generally a sheet having a current collector and an active material layer, but it also includes a form having a current collector, an active material layer, and a solid electrolyte layer in this order, and a form having a current collector, an active material layer, a solid electrolyte layer, and an active material layer in this order.

[0375] At least one of the solid electrolyte layer and the active material layer possessed by the electrode sheet is formed of the inorganic solid electrolyte composition of the present application. In the solid electrolyte layer and the active material layer formed of the inorganic solid electrolyte composition of the present application, the polymer binder formed of the dissolvable polymer is the same as the polymer binder of the solid electrolyte layer possessed by the solid electrolyte sheet for the all-solid-state secondary battery described above. Furthermore, the content of each component in the solid electrolyte layer or the active material layer is not particularly limited, and it is preferable that the meaning is the same as the meaning of the content of each component in the solid component of the inorganic solid electrolyte composition (electrode composition) of the present application. Among them, the content of the polymer binder is generally the same as the total content of the dissolvable polymer. The layer thickness of each layer constituting the electrode sheet of the present application 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 application can have other layers described above.

[0376] In addition, when the solid electrolyte layer or the active material layer is not formed of the inorganic solid electrolyte composition of the present application, it is formed of a general constitution layer forming material.

[0377] In the all-solid-state secondary battery sheet of the present application, at least one of the solid electrolyte layer and the active material layer is formed of the inorganic solid electrolyte-containing composition of the present application, and has a surface flatness that suppresses an increase in interface resistance between solid particles while firmly bonding the solid particles to each other. Therefore, the all-solid-state secondary battery sheet of the present application is used as a constituent layer of an all-solid-state secondary battery, and thus can achieve low resistance (high conductivity) and excellent cycle characteristics of the all-solid-state secondary battery. In particular, in the electrode sheet for an all-solid-state secondary battery and the all-solid-state secondary battery in which the active material layer is formed of the inorganic solid electrolyte-containing composition of the present application, the active material layer and the current collector exhibit firm adhesion, and further improvement in cycle characteristics can be achieved. Therefore, the all-solid-state secondary battery sheet of the present application is suitable for use as a sheet that can form a constituent layer of an all-solid-state secondary battery.

[0378] In the present application, each layer constituting the all-solid-state secondary battery sheet can be a single layer structure or a multilayer structure.

[0379] [Method for producing an all-solid-state secondary battery sheet]

[0380] The method for producing an all-solid-state secondary battery sheet of the present application is not particularly limited, and each layer described above can be produced using the inorganic solid electrolyte-containing composition of the present application. For example, a method in which a layer (coating and drying layer) composed of the inorganic solid electrolyte-containing composition is formed by film formation (coating and drying) on a substrate or a current collector (which can be via another layer) is preferred. Thereby, an all-solid-state secondary battery sheet having a substrate or a current collector and a coating and drying layer can be produced. In particular, when the inorganic solid electrolyte-containing composition of the present application is subjected to film formation on a current collector to produce an all-solid-state secondary battery sheet, firm adhesion of the current collector and the active material layer can be achieved. Here, the coating and drying layer refers to a layer formed by coating the inorganic solid electrolyte-containing composition of the present application and drying the dispersion medium (i.e., a layer formed using the inorganic solid electrolyte-containing composition of the present application and composed of the inorganic solid electrolyte-containing composition of the present application from which the dispersion medium is removed). As long as the dispersion medium can remain within the range that does not impair the effects of the present application, the active material layer and the coating and drying layer can have the dispersion medium remaining therein, and the amount of the dispersion medium remaining can be, for example, 3% by mass or less in each layer. The coating and drying layer contains a polymer binder formed by chemical reaction of a soluble polymer as described above.

[0381] In the method for producing an all-solid-state secondary battery sheet of the present application, each process such as coating, drying, and the like is described in the following method for producing an all-solid-state secondary battery.

[0382] In the above preferred method, when a sheet for a full solid-state secondary battery is produced by forming a film of the inorganic solid electrolyte-containing composition of the present application on a current collector, the adhesion of the current collector to the active material layer can be made strong.

[0383] In the method for producing a sheet for a full solid-state secondary battery of the present application, the coated and dried layer obtained in the above manner can also be subjected to pressurization. The pressurization conditions and the like are described later in the method for producing a full solid-state secondary battery.

[0384] Also, in the method for producing a sheet for a full solid-state secondary battery of the present application, the substrate, the protective layer (particularly the sheet), and the like can be peeled off.

[0385] [Full solid-state secondary battery]

[0386] The full solid-state secondary battery of the present application 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 a positive electrode. The negative electrode active material layer is preferably formed on a negative electrode current collector and constitutes a negative electrode.

[0387] At least one of the negative electrode active material layer, the positive electrode active material layer, and the solid electrolyte layer is formed of the inorganic solid electrolyte-containing composition of the present application, and preferably at least one of the solid electrolyte layer or the negative electrode active material layer and the positive electrode active material layer is formed of the inorganic solid electrolyte-containing composition of the present application. It is also one of the preferred modes that all the layers are formed of the inorganic solid electrolyte-containing composition of the present application. In the present application, the formation of the constituent layers of the full solid-state secondary battery from the inorganic solid electrolyte-containing composition of the present application means a mode including the formation of the constituent layers from the sheet for a full solid-state secondary battery of the present application (in which the sheet is obtained by removing layers other than the layer formed of the inorganic solid electrolyte-containing composition of the present application). As for the types and amounts of the components contained, the active material layer or the solid electrolyte layer formed of the inorganic solid electrolyte-containing composition of the present application is preferably the same as in the solid component of the inorganic solid electrolyte-containing composition of the present application (in which the amount of the polymer binder is generally the same as the total amount of the soluble polymers). In addition, when the active material layer or the solid electrolyte layer is not formed of the inorganic solid electrolyte-containing composition of the present application, a publicly known material can be used.

[0388] There are no particular restrictions on the thickness of each of the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer. From the perspective of the size of a general all-solid-state secondary battery, the thickness of each layer is preferably 10 to 1,000 μm, and more preferably 20 μm or more and less than 500 μm. In the all-solid-state secondary battery of the present application, 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.

[0389] The positive electrode active material layer and the negative electrode active material layer can each have a current collector on the side opposite the solid electrolyte layer.

[0390] <Frame>

[0391] The all-solid-state secondary battery of the present application can be used as an all-solid-state secondary battery in the above-described state according to the use, but in order to make it in the form of a dry cell, it is preferable to further enclose it in a suitable case. The case can be a metallic case or a case made of resin (plastic). In the case of using a metallic case, for example, a case made of an aluminum alloy or stainless steel can be mentioned. It is preferable that the metallic case be divided into a positive electrode side case and a negative electrode side case and be electrically connected to the positive electrode current collector and the negative electrode current collector, respectively. It is preferable that the case on the positive electrode side and the case on the negative electrode side be joined to be integrated with a spacer for preventing short circuiting therebetween.

[0392] Hereinafter, the all-solid-state secondary battery according to the preferred embodiment of the present application will be described with reference to Figure 1 , but the present application is not limited thereto.

[0393] Figure 1 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 application. When viewed from the negative electrode side, the all-solid-state secondary battery 10 of the present embodiment has, in this order, 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 the adjacent layer, and has an adjacent structure. By adopting such a structure, electrons (e - ) are supplied to the negative electrode side at the time of charging, and lithium ions (Li + ) are accumulated therein. On the other hand, at the time of discharging, the lithium ions (Li + ) accumulated in the negative electrode are returned to the positive electrode side, and electrons are supplied to the working portion 6. In the illustrated example, a bulb is used as a model in the working portion 6, and the bulb is made to emit light by discharging.

[0394] In the case where the all-solid-state secondary battery having the layer structure shown in Figure 1 is housed in a 2032 type coin cell case (for example, refer to Figure 2), and sometimes the all-solid-state secondary battery is also referred to as a laminate 12 for all-solid-state secondary battery. A battery produced by placing the laminate 12 for all-solid-state secondary battery in a 2032 type coin cell case 11 is referred to as an (coin type) all-solid-state secondary battery 13.

[0395] (anode active material layer, solid electrolyte layer, cathode active material layer)

[0396] In the all-solid-state secondary battery 10, the anode active material layer, the solid electrolyte layer, and the cathode active material layer are each formed of the inorganic solid electrolyte-containing composition of the present application. In the anode active material layer 4, the solid electrolyte layer 3, and the cathode active material layer 2, the polymer binder formed of a dissolvable polymer is the same as the polymer binder of the solid electrolyte layer possessed by the solid electrolyte sheet for all-solid-state secondary battery described above. The all-solid-state secondary battery 10 exhibits excellent battery performance. The inorganic solid electrolyte and the polymer binder contained in the anode active material layer 4, the solid electrolyte layer 3, and the cathode active material layer 2 can each be the same kind or different kinds.

[0397] In the present application, either one or both of the anode active material layer and the cathode active material layer is / are simply referred to as an active material layer or an electrode active material layer. Also, either one or both of the anode active material and the cathode active material is / are simply referred to as an active material or an electrode active material.

[0398] In the present application, when a layer is formed of the inorganic solid electrolyte-containing composition of the present application, an all-solid-state secondary battery having low resistance and excellent cycle characteristics can be achieved.

[0399] In the all-solid-state secondary battery 10, the cathode active material layer can be a lithium metal layer. As the lithium metal layer, a layer formed by piling up or molding a powder of lithium metal, a lithium foil, a lithium vapor deposition film, and the like can be given. The thickness of the lithium metal layer is not related to the thickness of the cathode active material layer described above, and can be, for example, 1 to 500 μm.

[0400] The anode current collector 5 and the cathode current collector 1 are preferably electron conductors.

[0401] In the present application, either one or both of the anode current collector and the cathode current collector is / are simply referred to as a current collector.

[0402] As a material forming the anode current collector, in addition to aluminum, aluminum alloy, stainless steel, nickel, titanium, and the like, a material in which carbon, nickel, titanium, or silver is surface-treated on aluminum or stainless steel (a material in which a thin film is formed) is preferable, and among them, aluminum and aluminum alloy are more preferable.

[0403] As a material forming the negative electrode current collector, in addition to aluminum, copper, copper alloy, stainless steel, nickel, and titanium, etc., a material in which carbon, nickel, titanium, or silver is surface-treated on aluminum, copper, copper alloy, or stainless steel is preferable, and aluminum, copper, copper alloy, and stainless steel are more preferable.

[0404] The shape of the current collector is usually a film-like shape, but a net, a perforated body, a lath body, a porous body, a foamed body, a molded body of a fiber group, or the like can also be used.

[0405] The thickness of the current collector is not particularly limited, and is preferably 1 to 500 μm. Furthermore, it is also preferable that a concave-convex structure be provided on the surface of the current collector by surface treatment.

[0406] In the above-described all-solid-state secondary battery 10, when a layer formed of a publicly known layer-forming material is provided in addition to the layer formed of the inorganic solid electrolyte composition-containing composition of the present application, the layer formed of the publicly known layer-forming material can also be applied.

[0407] In the present application, a functional layer, member, or the like can be appropriately inserted between or provided outside each of the negative electrode current collector, the negative electrode active material layer, the solid electrolyte layer, the positive electrode active material layer, and the positive electrode current collector. Furthermore, each layer can be configured as a single layer, or can be configured as a plurality of layers.

[0408] [Manufacture of all-solid-state secondary battery]

[0409] 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 each layer described above using the inorganic solid electrolyte composition-containing composition of the present application, etc. Hereinafter, a detailed description will be given.

[0410] The all-solid-state secondary battery of the present application can be manufactured by a method (manufacturing method of the all-solid-state secondary battery sheet of the present application) including (via) a step of forming a coating film (film formation) by appropriately applying the inorganic solid electrolyte composition-containing composition of the present application on a substrate (for example, a metal foil that becomes a current collector).

[0411] For example, a positive electrode active material layer is formed by coating an inorganic solid electrolyte-containing composition containing a positive electrode active material as a positive electrode material (positive electrode composition) on a metal foil as a positive electrode current collector to produce a positive electrode sheet for a full solid-state secondary battery. Next, a solid electrolyte layer is formed by coating an inorganic solid electrolyte-containing composition for forming a solid electrolyte layer on the positive electrode active material layer. Further, a negative electrode active material layer is formed by coating an inorganic solid electrolyte-containing composition containing a negative electrode active material as a negative electrode 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, a full 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 enclosed in a case as a desired full solid-state secondary battery.

[0412] Also, contrary to the method of forming each layer, a full 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 overlapping a positive electrode current collector.

[0413] As another method, the following method can be given. That is, a positive electrode sheet for a full solid-state secondary battery is produced as described above. Further, a negative electrode active material layer is formed by coating an inorganic solid electrolyte-containing composition containing a negative electrode active material as a negative electrode material (negative electrode composition) on a metal foil as a negative electrode current collector to produce a negative electrode sheet for a full solid-state secondary battery. Next, a solid electrolyte layer is formed on the active material layer of either of these sheets as described above. Also, the other of the positive electrode sheet for a full solid-state secondary battery and the negative electrode sheet for a full 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, a full solid-state secondary battery can be manufactured.

[0414] Also, as another method, the following method can be given. That is, a positive electrode sheet for a full solid-state secondary battery and a negative electrode sheet for a full solid-state secondary battery are produced as described above. Further, a solid electrolyte sheet composed of a solid electrolyte layer is produced by coating an inorganic solid electrolyte-containing composition on a substrate in addition to this. Also, it is laminated in a form in which the solid electrolyte layer peeled from the substrate is sandwiched by the positive electrode sheet for a full solid-state secondary battery and the negative electrode sheet for a full solid-state secondary battery. In this way, a full solid-state secondary battery can be manufactured.

[0415] Further, as described above, the positive electrode sheet for all-solid-state secondary battery or the negative electrode sheet for all-solid-state secondary battery and the solid electrolyte sheet for all-solid-state secondary battery are produced. Subsequently, the positive electrode sheet for all-solid-state secondary battery or the negative electrode sheet for all-solid-state secondary battery and the solid electrolyte sheet for all-solid-state secondary battery are overlapped 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 and are subjected to pressing. In this way, the solid electrolyte layer is transferred to the positive electrode sheet for all-solid-state secondary battery or the negative electrode sheet for all-solid-state secondary battery. Then, the solid electrolyte layer obtained by peeling the substrate of the solid electrolyte sheet for all-solid-state secondary battery and the negative electrode sheet for all-solid-state secondary battery or the positive electrode sheet for 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 subjected to pressing. In this way, the all-solid-state secondary battery can be produced. The method and the pressing conditions and the like in the method are not particularly limited, and the method and the pressing conditions and the like described in the pressing in the composition to be coated described later can be applied.

[0416] The solid electrolyte layer and the like can also be formed by pressing molding under the pressing conditions described later, for example, on the substrate or the active material layer, and a sheet-shaped molded body of the solid electrolyte or the active material can also be used.

[0417] In the production method described above, the inorganic solid electrolyte-containing composition of the present application can be used for any one of the positive electrode composition, the inorganic solid electrolyte-containing composition, and the negative electrode composition, and preferably the inorganic solid electrolyte-containing composition of the present application is used for the inorganic solid electrolyte-containing composition, and the inorganic solid electrolyte-containing composition of the present application can also be used for any composition.

[0418] When the solid electrolyte layer or the active material layer is formed from a composition other than the inorganic solid electrolyte-containing composition of the present application, as a material therefor, a composition generally used and the like can be mentioned. Further, when the all-solid-state secondary battery is produced without forming the negative electrode active material layer, ions of a metal belonging to Group 1 or Group 2 of the periodic table, which are accumulated in the negative electrode current collector by the initialization described later or charging at the time of use, are combined with electrons and precipitated as a metal on the negative electrode current collector and the like, and thus the negative electrode active material layer can also be formed.

[0419] <Formation (Film Formation) of Each Layer>

[0420] The film formation (coating and drying) of the inorganic solid electrolyte-containing composition of the present application is performed while chemically reacting the soluble polymer as a component constituting the polymer binder and gradually solidifying or precipitating. The method of chemical reaction is not particularly limited, and for example, a method of selecting the drying conditions in the film formation step can be mentioned.

[0421] The coating method of the inorganic solid electrolyte composition-containing composition, etc. is not particularly limited and can be appropriately selected. For example, coating (preferably wet coating), spraying, spin coating, dip coating, slit coating, stripe coating, and bar coating can be given. The coating conditions can be appropriately determined, but are preferably set to conditions under which the components constituting the polymer binder described above do not undergo chemical reactions, for example, the temperature conditions are preferably set to a temperature lower than the drying temperature described below.

[0422] The coated inorganic solid electrolyte composition is subjected to a drying treatment (heat treatment). In the drying treatment, the dissolving state of the dissolving polymer in the coated inorganic solid electrolyte composition is maintained while being chemically reacted with the adsorption of the solid particles, for example, by solidifying or precipitating in a particulate form, the rise in the interfacial resistance can be suppressed while the solid particles are bonded to each other. By the solidification or precipitation of the dissolving polymer, in combination with the excellent dispersion properties of the inorganic solid electrolyte composition-containing composition, the solid particles can be bonded while suppressing the fluctuation in the contact state and the rise in the interfacial resistance, and a coated dried layer having a flat surface can be formed.

[0423] It is considered that in the drying treatment, when the inorganic solid electrolyte composition-containing composition of the present application is heated, as the temperature rises, the chemical reaction of the functional group or partial structure (I) and the functional group or partial structure (II) possessed by the dissolving polymer is promoted, and the volatilization of the dispersion medium is also promoted, the dissolving polymer in the dissolving state is polymerized with a high molecular weight, and the solubility in the dispersion medium gradually decreases. In this way, the dissolving polymer in the dissolving state is solidified or precipitated as a polymer binder.

[0424] The drying treatment can be performed after the inorganic solid electrolyte composition-containing composition is coated respectively, or after being coated in multiple layers.

[0425] The drying conditions are not particularly limited as long as the above chemical reaction is performed. For example, as the drying temperature, it can be appropriately set according to the types of the functional group or partial structure (I) and the functional group or partial structure (II), etc., and in consideration of the above reaction conditions in which the chemical reaction is performed. For example, it 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 in this temperature range, the dissolving polymer is chemically reacted while the dispersion medium is removed, and thus the coated dried layer can be formed. Furthermore, the temperature is not excessively high, and thus the components of the all-solid-state secondary battery are not damaged, and thus it is preferable. As a result, in the all-solid-state secondary battery, excellent overall performance is exhibited, and good adhesion and good ion conductivity without pressure can be obtained.

[0426] As described above, when the inorganic solid electrolyte-containing composition of the present application is coated and dried, the deviation in the contact state can be suppressed and the solid particles can be bound, and a coated and dried layer (inorganic solid electrolyte layer) having a flat surface can be formed.

[0427] After the inorganic solid electrolyte-containing composition is coated, preferably, the layers are overlaid or the all-solid-state secondary battery is produced, and then the layers or the all-solid-state secondary battery is subjected to pressurization. As the pressurization method, a hydraulic cylinder press or the like can be given. There is no particular limitation on the pressurization force, and generally, it is preferably in the range of 5 to 1500 MPa.

[0428] Further, the coated inorganic solid electrolyte-containing composition can be subjected to heating at the same time as the pressurization. There is no particular limitation on the heating temperature, and generally, it is in the range of 30 to 300°C. Pressing can also be performed at a temperature higher than the glass transition temperature of the inorganic solid electrolyte. In addition, pressing can also be performed at a temperature higher than the glass transition temperature of the polymer binder. However, generally, it is a temperature not exceeding the melting point of the polymer.

[0429] Pressurization can be performed in a state where the coating solvent or the dispersion medium is previously dried, or pressurization can be performed in a state where the solvent or the dispersion medium remains.

[0430] In addition, the respective compositions can be coated at the same time, or the coating, drying, and pressing can be performed at the same time and / or stepwise. The layers can be laminated by transfer after being coated on respective substrates.

[0431] As the manufacturing procedure, for example, in the coating, the environment in the heating or pressurization is not particularly limited, and it can be any of atmospheric pressure, dry air (dew point -20°C or lower), an inactive gas (for example, argon, helium, nitrogen), and the like.

[0432] The pressing time can be a short time (for example, within several hours) in which a high pressure is applied, or it can be a long time (one day or more) in which a moderate pressure is applied. In the case of the all-solid-state secondary battery, for example, a constraining tool (screw fastening pressure or the like) of the all-solid-state secondary battery can be used to continuously apply a moderate pressure.

[0433] The pressing pressure can be a uniform pressure or a different pressure with respect to the pressure-receiving portions such as the surface of the sheet.

[0434] The pressing pressure can be changed depending on the area of the pressure-receiving portion or the film thickness. Further, the same portion can be changed in stages with different pressures.

[0435] The pressing surface can be smooth or rough.

[0436] <Initialization>

[0437] The all-solid-state secondary battery manufactured in the above manner is preferably initialized after the manufacturing or before the use. The initialization is not particularly limited, and for example, initial charge and discharge can be performed in a state where the pressing pressure is increased, and thereafter, the pressure is released until the general use pressure of the all-solid-state secondary battery is reached.

[0438] [Use of the all-solid-state secondary battery]

[0439] The all-solid-state secondary battery of the present application can be applied to various uses. The application mode is not particularly limited, and for example, in the case of being mounted on an electronic device, a notebook computer, a pen input computer, a mobile computer, an electronic book reader, a mobile phone, a wireless telephone handset, a pager, a hand-held terminal, a portable facsimile machine, a portable copying machine, a portable printer, a stereo headphone, a camcorder, a liquid crystal television, a hand-held vacuum cleaner, a portable CD, a small-sized disk, an electric shaver, a transceiver, an electronic diary, a calculator, a memory card, a portable recorder, a radio, a backup power supply, and the like can be mentioned. As other civil products, a car, an electric vehicle, a motor, an illuminating appliance, a toy, a game machine, a load regulator, a timepiece, a flash light, a camera, and a medical instrument (a cardiac pacemaker, a hearing aid, a shoulder massager, and the like) can be mentioned. Furthermore, it can be used as various military products and aviation products. Moreover, it can be combined with a solar cell.

[0440] Example

[0441] Hereinafter, the present application will be further explained in detail according to examples, but the present application is not limited to the following examples. In the following examples, "parts" and "%" indicating the composition are based on mass unless otherwise specified. In the present application, "room temperature" means 25°C.

[0442] 1. Synthesis of polymer and preparation of polymer solution

[0443] The polymer shown in the following chemical formula was synthesized as follows, and a polymer solution was prepared.

[0444] First, as the dissolvable polymer CI-I or CI-II having the functional group or the partial structure (I) or (II), polymers B-1 to B-6, B-10, B-14, and B-15 were synthesized, respectively.

[0445] [Synthesis Example 1: Synthesis of polymer B-1 and preparation of polymer solution B-1]

[0446] A monomer solution was prepared by adding dodecyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) 28.8 g, hydroxyethyl acrylate (manufactured by FUJIFILM Wako Pure Chemical Corporation) 7.2 g, and polymerization initiator V-601 (trade name, manufactured by FUJIFILM Wako Pure Chemical Corporation) 0.1 g into a 100-mL graduated cylinder and dissolving them in butyl butyrate 36 g. Butyl butyrate 18 g was added to a 300-mL three-necked flask, and the above monomer solution was added dropwise over 2 hours while stirring at 80°C. After the dropwise addition, the temperature was raised to 90°C, and stirring was performed for 2 hours. Then, it was dropped into methanol, and a polymer B-1 was obtained as a precipitate. After performing reduced-pressure drying at 60°C for 5 hours, it was dissolved in an arbitrary solvent. In this way, a polymer B-1 (mass-average molecular weight 50,000) was synthesized, and an adhesive solution B-1 (concentration 10 mass%) composed of the polymer B-1 was obtained.

[0447] [Synthesis Examples 2 to 7: Synthesis of polymers B-3 to B-6, B-10 and preparation of polymer solutions B-2 to B-6, B-10]

[0448] In Synthesis Example 1, compounds into which each component was introduced were used so that the polymers B-3 to B-6 and B-10 would have the composition shown in the following chemical formulae (kinds and amounts of components), and otherwise, the polymers B-3 to B-6 and B-10 (acrylic polymers or vinyl polymers) were synthesized in the same manner as in Synthesis Example 1, and polymer solutions B-3 to B-6 and B-10 (concentration 10 mass%) composed of each polymer were obtained, respectively.

[0449] Further, a polymer solution B-2 (concentration 10 mass%) was prepared using a polymer B-2 (aminoethylated acrylic polymer NK-350 (trade name, manufactured by Nippon Shokubai Co., Ltd.) having a polyethyleneimine chain).

[0450] [Synthesis Example 8: Synthesis of polymer B-14 and preparation of polymer solution B-14]

[0451] To a pressure vessel were added ion exchange water 200 parts by mass, vinylidene fluoride 130 parts by mass, hexafluoropropene 50 parts by mass, hydroxyethyl acrylate 20 parts by mass, and diisopropyl peroxydicarbonate 2 parts by mass, and stirring was performed at 30°C for 24 hours. After completion of polymerization, the precipitate was filtered and dried at 100°C for 10 hours, thereby obtaining a polymer (binder) B-14. The weight average molecular weight of the obtained binder was 60,000. In this way, the polymer B-14 (fluoropolymer) was synthesized, and a polymer solution B-14 (concentration 10 mass%) composed of the polymer B-14 was obtained.

[0452] [Synthesis Example 9: Synthesis of polymer B-15 and preparation of polymer solution B-15]

[0453] To a pressure vessel were added toluene 150 parts by mass, styrene 25 parts by mass, 1,3-butadiene 75 parts by mass, and 1 part by mass of a polymerization initiator V-601 (manufactured by Wako Pure Chemical Industries, Ltd.), and the temperature was raised to 80°C, and stirring was performed for 3 hours. Then, the temperature was raised to 90°C, and the reaction was performed until the conversion rate reached 100%. The obtained solution was again precipitated in methanol, and the obtained solid was dried to obtain 100 parts by mass of a polymer. To the polymer were added 3 parts by mass of 2,6-di-tert-butyl-p-cresol and 3 parts by mass of maleic anhydride, and the reaction was performed at 180°C for 5 hours. The obtained solution was again precipitated in acetonitrile, and the obtained solid was dried to obtain a polymer. The weight average molecular weight of the polymer was 90,000. Then, 50 parts by mass of the obtained polymer was dissolved in 50 parts by mass of cyclohexane and 150 parts by mass of THF (tetrahydrofuran), and the solution was set to 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, and the reaction was performed under a hydrogen pressure of 10 kg / cm 2 The reaction was performed for 1 hour, distilled off, and dried to obtain a polymer B-15. The weight average molecular weight of the polymer B-15 was 92,000.

[0454] In this way, the polymer B-15 (hydrocarbon polymer) was synthesized, and a polymer solution B-15 (concentration 10 mass%) composed of the polymer B-15 was obtained.

[0455] Next, as the dissolvable polymers C2 having the functional groups or partial structures (I) and (II), polymers B-7 to B-9 and B-11 to B-13 were synthesized, respectively.

[0456] [Synthesis Examples 10 to 15: Synthesis of polymers B-7 to B-9, B-11 to B-13 and preparation of polymer solutions B-7 to B-9, B-11 to B-13]

[0457] In Synthesis Example 1, a compound into which each of the constituent components was introduced was used to make polymers B-7 to B-9 and B-11 to B-13 into the composition shown by the following chemical formula (kind and content of the constituent components), and polymers B-7 to B-9 and B-11 to B-13 (acrylic polymers or vinyl polymers) were synthesized in the same manner as in Synthesis Example 1, except for this, and polymer solutions B-7 to B-9 and B-11 to B-13 (concentration 10 mass%) composed of each of the polymers were obtained.

[0458] Next, a comparative use solubility polymer BA-1 was synthesized.

[0459] [Synthesis Example 16: Synthesis of Polymer BA-1 and Preparation of Polymer Solution BA-1]

[0460] In Synthesis Example 1, a compound into which each of the constituent components was introduced was used to make polymers B-7 to B-9 and B-11 to B-13 into the composition shown by the following chemical formula (kind and content of the constituent components), and polymers B-7 to B-9 and B-11 to B-13 (acrylic polymers or vinyl polymers) were synthesized in the same manner as in Synthesis Example 1, except for this, and polymer solutions B-7 to B-9 and B-11 to B-13 (concentration 10 mass%) composed of each of the polymers were obtained.

[0461] [Synthesis Example 17: Synthesis of Polymer BA-2 and Preparation of Polymer Dispersion BA-2]

[0462] A monomer solution was prepared by adding 11.7 g of hydroxyethyl acrylate (manufactured by FUJIFILM Wako Pure Chemical Corporation) and 0.17 g of a polymerization initiator V-601 (trade name, manufactured by FUJIFILM Wako Pure Chemical Corporation) to a 100-mL volumetric flask and dissolving them in 13.6 g of butyl butyrate. A macromonomer solution of 10.2 g was added to a 200-mL three-necked flask, dissolved in 16.9 g of butyl butyrate, and the monomer solution was added dropwise over 2 hours while stirring at 80°C. After the addition was completed, the temperature was increased to 90°C and stirring was performed for 2 hours to synthesize a (meth)acrylic polymer dispersion BA-2, which was diluted with butyl butyrate to a concentration of 10% to prepare. The weight average molecular weight of the polymer BA-2 thus obtained was 150,000. The average particle diameter of the binder in the polymer dispersion BA-2 was 80 nm.

[0463] Thus, the polymer BA-2 (particulate polymer) was synthesized, and a polymer dispersion BA-2 (concentration 10 mass%) composed of the polymer BA-2 was obtained.

[0464] (Synthesis of macromonomer)

[0465] To a 1 L volumetric flask, methyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) 130.2 g, dodecyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) 330.7 g, 3-mercaptopropionic acid 4.5 g, and polymerization initiator V-601 (manufactured by FUJIFILM Wako Pure Chemical Corporation) 4.61 g were added, and stirred to uniformly dissolve to prepare a monomer solution. To a 2 L three-necked flask, toluene (manufactured by FUJIFILM Wako Pure Chemical Corporation) 465.5 g was added, and the above monomer solution was added dropwise over 2 hours while stirring at 80°C. After the dropwise addition, after stirring at 80°C for 2 hours, the temperature was raised to 90°C and stirred for 2 hours. 2,2,6,6-tetramethylpiperidine 1-oxyl (manufactured by FUJIFILM Wako Pure Chemical Corporation) 275 mg, glycidyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) 27.5 g, tetrabutylammonium bromide (manufactured by FUJIFILM Wako Pure Chemical Corporation) 5.5 g were added, and stirred at 120°C for 3 hours. After the solution was left to stand at room temperature, poured into 1800 g of methanol, and the supernatant was removed. Butyl butyrate was added thereto, and the methanol was distilled off under reduced pressure to obtain a butyl butyrate solution of a macromonomer. The solid content concentration was 48.9 mass%. The weight average molecular weight of the macromonomer thus obtained was 10,000.

[0466] [Synthesis Example 18: Synthesis of Polymer BA-3 and Preparation of Polymer Dispersion BA-3]

[0467] A monomer solution was prepared by adding 8.4 g of methyl methacrylate (manufactured by FUJIFILM Wako Pure Chemical Corporation), 3.3 g of 2-[(3,5-dimethylpyrazole)carbonylamino]ethyl methacrylate (manufactured by FUJIFILM Wako Pure Chemical Corporation), and 0.17 g of polymerization initiator V-601 (trade name, manufactured by FUJIFILM Wako Pure Chemical Corporation) to a 100 mL volumetric flask and dissolving them in 13.6 g of butyl butyrate. A monomer solution of 10.2 g was added to a 200 mL three-necked flask, dissolved in 16.9 g of butyl butyrate, and added dropwise over 2 hours with stirring at 80 °C. After the addition was complete, the mixture was stirred at 80 °C for 2 hours, then heated to 90 °C and stirred for 2 hours to synthesize a dispersion of (meth)acrylic acid polymer BA-3, which was then diluted with butyl butyrate to a concentration of 10%. The polymer BA-3 obtained in this manner had a mass-average molecular weight of 200,000. The average particle size of the binder in the polymer dispersion BA-2 is 70 nm.

[0468] [Synthesis Example 19: Synthesis of Polymer BA-4 and Preparation of Polymer Solution BA-4]

[0469] A monomer solution was prepared by adding 32.4 g of dodecyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), 3.6 g of acrylic acid (manufactured by FUJIFILM Wako Pure Chemical Corporation), and 0.1 g of polymerization initiator V-601 (trade name, manufactured by FUJIFILM Wako Pure Chemical Corporation) to a 100 mL graduated cylinder and dissolving it in 36 g of butyl butyrate. 18 g of butyl butyrate was added to a 300 mL three-necked flask, and the monomer solution was added dropwise over 2 hours at 80°C with stirring. After the addition was complete, the temperature was raised to 90°C and stirred for 2 hours. Then, it was added dropwise to methanol, and polymer BA-4 was obtained as a precipitate. After drying under reduced pressure at 60°C for 5 hours, it was dissolved in any solvent. Thus, polymer BA-4 (mass average molecular weight 50,000) was synthesized, and an adhesive solution BA-4 (concentration 10% by mass) composed of polymer BA-4 was obtained.

[0470] The synthesized polymers are shown below. The numbers listed in the lower right corner of each component indicate the content (mass %). The mass-average molecular weights of each polymer obtained by the above determination method are shown in Table 1.

[0471] In addition, the synthetic polymer is dissolved in the dispersion medium in all of the compositions described below.

[0472] [Chemical Formula 3]

[0473]

[0474] [Chemical Formula 4]

[0475]

[0476] [Chemical Formula 5]

[0477]

[0478] [Chemical Formula 6]

[0479]

[0480] 2. Preparation of a composition containing an adhesive-forming component (hereinafter, referred to as an adhesive solution)

[0481] The polymer solution of the synthetic dissolving polymer CI-I and the polymer solution of the synthetic dissolving polymer CI-II were mixed in the combinations shown in Table 1 at a ratio of 1:1 (solid content amount) of the dissolving polymers, and adhesive solutions S-1 to S-6, S-10 to S-12, and S-16 to S-18 were prepared. Further, the comparative adhesive dispersion T-6 and the adhesive solutions T-7 and T-8 were mixed in the combinations shown in Table 1.

[0482] As the adhesive solutions S-7 to S-9 and S-13 to S-15 containing the dissolving polymer C2 and the comparative adhesive solutions T-1 to T-5, the polymer solutions prepared as described above shown in Table 1 were used directly.

[0483] Further, (I) and (II) written at the beginning of the functional group or partial structure in the column of "functional group or partial structure" in Table 1 below indicate the functional group or partial structure selected from Group (I) or Group (II), respectively. Further, in the case of the dissolving polymer C2, the functional group or partial structure selected from both groups is written using " / ".

[0484] Further, the dissolving polymer CI-II contained in the adhesive solutions T-3 to T-5 is written in the column of "dissolving polymer CI-I or C2". The ethylene glycol and the polymer BA-4 of the adhesive solutions T-7 and T-8 are written in the column of "dissolving polymer CI-I or C2" or "dissolving polymer CI-II", respectively.

[0485] In Table 1, "-" in each column means that the corresponding component is not present.

[0486]

[0487] 3. Synthesis of sulfide inorganic solid electrolyte

[0488] [Synthesis Example A]

[0489] The sulfide inorganic solid electrolyte was synthesized by reference to the non-patent literature of T. Ohtomo, A. Hayashi, M. Tatsumisago, Y. Tsuchida, S. Hama, K. Kawamoto, Journal of Power Sources, 233, (2013), pp 231-235 and A. Hayashi, S. Hama, H. Morimoto, M. Tatsumisago, T. Minami, Chem. Lett., (2001), pp 872-873.

[0490] 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 in a glove box under an argon atmosphere (dew point -70°C), and were put into an agate mortar, and were mixed using 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.

[0491] Next, 66 g of zirconia beads having a diameter of 5 mm were put into a 45 mL zirconia container (manufactured by Fritsch Co., Ltd.), and the total amount of the mixture of lithium sulfide and phosphorus pentasulfide described above was put into the container, and the container was completely closed under an argon atmosphere. The container was set in a planetary ball mill P-7 (trade name) manufactured by Fritsch Co., Ltd., and mechanical grinding was performed at a temperature of 25°C and a rotation speed of 510 rpm for 20 hours, and thereby 6.20 g of a yellow powder of the sulfide inorganic solid electrolyte (Li-P-S glass, hereinafter, sometimes denoted as LPS) was obtained. The particle diameter of the Li-P-S glass was 15 μm.

[0492] [Example 1]

[0493] Each composition shown in Tables 2-1 to 2-3 (collectively referred to as Table 2) was prepared as follows.

[0494] <Preparation of inorganic solid electrolyte-containing composition>

[0495] To a zirconia-made 45 mL container (Fritsch Co., Ltd.) were charged zirconia beads of 5 mm in diameter 60 g, 8.4 g of LPS synthesized in Synthesis Example A, each of the binder solutions (solid content mass) shown in the "binder solution" column of Table 2 0.6 g, and butyl butyrate 11 g (total amount) as a dispersion medium. Then, the container was set in a planetary ball mill P-7 (trade name) of Fritsch Co., Ltd. Mixing was performed at 25°C and 150 rpm for 10 minutes to prepare inorganic solid electrolyte compositions (slurries) K-1 to K-18 and Kc1 to Kc8, respectively.

[0496] <Preparation of positive electrode composition>

[0497] To a zirconia-made 45 mL container (Fritsch Co., Ltd.) were charged zirconia beads of 5 mm in diameter 60 g, 8.4 g of LPS synthesized in Synthesis Example A, each of the binder solutions (solid content mass) shown in the "binder solution" column of Table 2 0.6 g, and butyl butyrate 11 g (total amount) as a dispersion medium. Then, the container was set in a planetary ball mill P-7 (trade name) of Fritsch Co., Ltd. Mixing was performed at 25°C and 150 rpm for 10 minutes to prepare inorganic solid electrolyte compositions (slurries) K-1 to K-18 and Kc1 to Kc8, respectively.

[0498] <Preparation of negative electrode composition>

[0499] To a 45 mL container of zirconia (Fritsch Co., Ltd.) were put 60 g of zirconia beads of 5 mm in diameter, and 8.0 g of LPS synthesized in Synthesis Example A, 0.4 g (solid content mass) of each of the binder solutions shown in "Binder solution" of Table 2, and 17.5 g (total amount) of the dispersion medium shown in Table 1. The container was set in a planetary ball mill P-7 (trade name) of Fritsch Co., Ltd., and mixed at 300 rpm for 60 minutes at a temperature of 25°C. Then, 9.5 g of silicon (Si, Aldrich, CO. LTD.) was put as a negative electrode active material, and 1.0 g of VGCF (SHOWA DENKO K.K.) was put as a conductive aid, and similarly, the container was set in the planetary ball mill P-7, and mixed at 100 rpm for 10 minutes at a temperature of 25°C, to prepare negative electrode compositions (slurries) NK-1 to NK-18 and NKc1 to NKc8, respectively.

[0500]

[0501]

[0502]

[0503]

[0504] LPS: LPS synthesized in Synthesis Example A

[0505] NMC: LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2

[0506] Si: Silicon

[0507] AB: Acetylene black

[0508] VGCF: Carbon nanotube

[0509] <Manufacture of Solid Electrolyte Sheet for All-solid-state Secondary Battery>

[0510] Each of the inorganic solid electrolyte-containing compositions shown in the column of "Solid electrolyte composition No." of Table 3-1 obtained above was coated on an aluminum foil having a thickness of 20 μm using a baking applicator (trade name: SA-201, TESTER SANGYO CO,. LTD.), heated at 100°C for 2 hours, and the inorganic solid electrolyte-containing composition was dried (removal of the dispersion medium while chemically reacting functional groups or partial structures with each other). Then, using a hot press, the dried inorganic solid electrolyte-containing composition was heated and pressurized at a temperature of 120°C and a pressure of 40 MPa for 10 seconds, whereby solid electrolyte sheets for all-solid-state secondary batteries (labeled as solid electrolyte sheets in Table 3-1) 101 to 118, cl l to cl 5, and c26 to c28 were produced, respectively. The film thickness of the solid electrolyte layer was 50 μm.

[0511] <Production of positive electrode sheet for all-solid-state secondary battery>

[0512] Each of the positive electrode compositions shown in the column of "Positive electrode composition No." of Table 3-2 obtained above was coated on an aluminum foil having a thickness of 20 μm using a baking applicator (trade name: SA-201), heated at 100°C for 1 hour, further heated at 110°C for 1 hour, and the positive electrode composition was dried (removal of the dispersion medium while chemically reacting functional groups or partial structures with each other). Then, using a hot press, the dried positive electrode composition was pressurized (10 MPa, 1 minute) at 25°C, whereby positive electrode sheets for all-solid-state secondary batteries having a positive electrode active material layer with a film thickness of 80 μm (labeled as positive electrode sheets in Table 3-2) 119 to 136, cl 6 to cl 20, and c29 to c31 were produced, respectively.

[0513] <Production of negative electrode sheet for all-solid-state secondary battery>

[0514] Each of the negative electrode compositions shown in the column of "Negative electrode composition No." of Table 3-3 obtained above was coated on a copper foil having a thickness of 20 μm using a baking applicator (trade name: SA-201), heated at 100°C for 1 hour, further heated at 110°C for 1 hour, and the negative electrode composition was dried (removal of the dispersion medium while chemically reacting functional groups or partial structures with each other). Then, using a hot press, the dried negative electrode composition was pressurized (10 MPa, 1 minute) at 25°C, whereby negative electrode sheets for all-solid-state secondary batteries having a negative electrode active material layer with a film thickness of 70 μm (labeled as negative electrode sheets in Table 3-3) 137 to 154, cl 6 to cl 20, and c29 to c31 were produced, respectively.

[0515] <Evaluation 1: Dispersion stability>

[0516] Each of the prepared compositions (slurries) was put into a glass test tube of 10 mm in diameter and 4 cm in height until a height of 4 cm, and left to stand for 24 hours at 25°C. The solid content ratio of 1 cm amount was calculated from the liquid level of the slurry before and after the standing. Specifically, 1 cm of liquid was taken from the liquid level of the slurry downward immediately after the standing, and dried by heating at 120°C for 2 hours in an aluminum cup. The mass of the solid content amount in the cup after the measurement was measured, and each of the solid content amounts before and after the standing was obtained. The solid content ratio [WA / WB] of the solid content amount after the standing WA relative to the solid content amount before the standing WB was obtained.

[0517] The ease of precipitation (precipitability) of the inorganic solid electrolyte was evaluated as the dispersion stability of the inorganic solid electrolyte composition according to which of the following evaluation criteria the solid content ratio was included. In the present test, the closer the above solid content ratio to 1, the more excellent the dispersion stability was shown, and the evaluation criteria "C" or more was the pass level. The results are shown in Table 3.

[0518] Evaluation Criteria

[0519] A: 0.9 ≤ solid content ratio ≤ 1.0

[0520] B: 0.6 ≤ solid content ratio < 0.9

[0521] C: 0.3 ≤ solid content ratio < 0.6

[0522] D: solid content ratio < 0.3

[0523] < Evaluation 2: Handleability >

[0524] After peeling the constituent layer (solid electrolyte layer or electrode active material layer) of each of the solid electrolyte sheet for all-solid-state secondary batteries, the positive electrode sheet for all-solid-state secondary batteries, and the negative electrode sheet for all-solid-state secondary batteries from the base material (aluminum foil or copper foil), a test piece of 20 mm in length × 20 mm in width was cut out. For the test piece, the thickness of the layer was measured at 5 points using a constant voltage thickness gauge (manufactured by TECLOCK Co., Ltd.), and the arithmetic mean of the thickness of the layer was calculated.

[0525] According to each of the measured values and the arithmetic mean thereof, the larger of the deviation values (%) obtained using the following formula (a) or (b) (the maximum deviation value) was applied to the following evaluation criteria, and the handleability was evaluated. In the present test, the smaller the maximum deviation value (%) was, the more uniform the thickness of the solid electrolyte layer or the active material layer was, that is, each of the compositions showed an appropriate viscosity (flowability) and was able to form a coating film with a flat film formation surface (excellent handleability). In the present test, the evaluation criteria "C" or more was the pass level. The results are shown in Table 3.

[0526] Formula (a): 100 x (maximum value - arithmetic mean value in layer thickness at 5 points) / (arithmetic mean value)

[0527] Formula (b): 100 x (arithmetic mean value - minimum value in layer thickness at 5 points) / (arithmetic mean value)

[0528] For each test piece, the measurement site of the layer thickness was set to the following "5 points: A to E".

[0529] First, as shown in Figure 3 , three virtual lines y1, y2, and y3 that equally divide the longitudinal direction of the test piece TP into four were drawn, and then, three virtual lines x1, x2, and x3 that equally divide the lateral direction of the test piece TP into four were drawn, and the surface of the test piece TP was divided into a lattice shape.

[0530] The measurement points were set to the intersection point A of the virtual lines x1 and y1, the intersection point B of the virtual lines x1 and y3, the intersection point C of the virtual lines x2 and y2, the intersection point D of the virtual lines x3 and y1, and the intersection point E of the virtual lines x3 and y3.

[0531] - Evaluation Criteria -

[0532] A: Maximum deviation value < 3%

[0533] B: 3% ≤ Maximum deviation value < 5%

[0534] C: 5% ≤ Maximum deviation value < 10%

[0535] D: 10% ≤ Maximum deviation value

[0536] [Table 3-1]

[0537]

[0538] [Table 3-2]

[0539]

[0540] [Table 3-3]

[0541]

[0542] <Manufacture of all-solid-state secondary battery>

[0543] An all-solid-state secondary battery (No. 101) having a layer structure as shown in Figure 1 was produced as follows.

[0544] (Production of positive electrode sheet for all-solid-state secondary battery having solid electrolyte layer)

[0545] By having the solid electrolyte layer in contact with the positive electrode active material layer, the solid electrolyte sheet shown in the "Solid Electrolyte Layer" column of Table 4-1 was laminated onto the positive electrode active material layer of each all-solid-state secondary battery positive electrode sheet shown in the "Electrode Active Material Layer" column of Table 4-1. After being pressurized at 50 MPa at 25°C and transferred (lamination) using a press, it was pressurized at 600 MPa at 25°C, thereby producing all-solid-state secondary battery positive electrode sheets 119-136, c16-c20 and c29-c31 (with a solid electrolyte layer thickness of 60 μm) having a solid electrolyte layer of 30 μm.

[0546] (Fabrication of negative electrode sheet for all-solid-state secondary batteries with solid electrolyte layer)

[0547] Next, with the solid electrolyte layer in contact with the negative electrode active material layer, the solid electrolyte sheet shown in the "Solid Electrolyte Layer" column of Table 4-2 was laminated onto the negative electrode active material layer of each all-solid-state secondary battery negative electrode sheet shown in the "Electrode Active Material Layer" column of Table 4-2. After being pressurized at 50 MPa at 25°C and transferred (laminated) using a press, it was pressurized at 600 MPa at 25°C. Thus, all-solid-state secondary battery negative electrode sheets 137-154, c21-c25 and c32-c34 (with a solid electrolyte layer thickness of 50 μm) with a solid electrolyte layer of 30 μm were produced.

[0548] (Manufacturing of all-solid-state secondary batteries)

[0549] 1. Manufacturing of all-solid-state secondary batteries No. 101~118, C101~C105 and C111~C113

[0550] The positive electrode sheet No. 119 (aluminum foil with the solid electrolyte layer already peeled off) for an all-solid-state secondary battery with the aforementioned solid electrolyte layer is cut into circular plates with a diameter of 14.5 mm, and as shown in the figure. Figure 2 The assembly shown includes spacers and gaskets (in...) Figure 2 In a stainless steel 2032-type button battery case 11 (not shown), lithium foil cut into disc shapes with a diameter of 15 mm is layered on a solid electrolyte layer. After further layering stainless steel foil on top, the 2032-type button battery case 11 is riveted together, thereby manufacturing a [missing information - likely a battery type]. Figure 2 The all-solid-state secondary battery 13 shown is No. 101. All-solid-state secondary batteries (half-cells) manufactured in this way have… Figure 1 The layer structure shown (where the lithium foil corresponds to the negative electrode active material layer 2 and the negative electrode current collector 1).

[0551] In the production of the all-solid-state secondary battery No. 101 described above, instead of the positive electrode sheet for all-solid-state secondary battery No. 119 provided with a solid electrolyte layer, the positive electrode sheet for all-solid-state secondary battery indicated by No. shown in the column of "electrode active material layer" of Table 4-1 provided with a solid electrolyte layer was used, and otherwise, the all-solid-state secondary batteries (half cells) Nos. 102 to 118, clOl to cl05, and clll to cl 13 were produced in the same manner as in the production of the all-solid-state secondary battery No. 101.

[0552] 2. Production of all-solid-state secondary batteries Nos. 119 to 136, cl06 to cl 10, and cl 14 to cl 16

[0553] The negative electrode sheet for all-solid-state secondary battery No. 137 provided with the solid electrolyte layer obtained above (aluminum foil of the sheet material containing the solid electrolyte was peeled off) was cut into a circular plate shape having a diameter of 14.5 mm, and was introduced into a stainless steel 2032 type coin cell case 11 assembled with a spacer and a gasket (not shown in Figure 2 Figure 2 Next, the positive electrode sheet for all-solid-state secondary battery produced below was laminated on the solid electrolyte layer with the positive electrode sheet (positive electrode active material layer) punched out in a diameter of 14.0 mm. After further laminating a stainless steel foil thereon, the 2032 type coin cell case 11 was riveted, and thus the all-solid-state secondary battery (full cell) No. 119 shown in Figure 2

[0554] The positive electrode sheet for all-solid-state secondary battery for producing the all-solid-state secondary battery (No. 119) was prepared as follows.

[0555] (Preparation of positive electrode composition)

[0556] Into a zirconia-made 45 mL container (manufactured by Fritsch Co., Ltd.) were put 180 zirconia beads each having a diameter of 5 mm, and 2.7 g of LPS synthesized in Synthesis Example A above, 0.3 g of KYNAR FLEX 2500-20 (trade name, PVdF-HFP: polyvinylidene fluoride-hexafluoropropylene copolymer, manufactured by ARKEMA) as a solid component, and 22 g of butyl butyrate. The container was set in a planetary ball mill P-7 (trade name, manufactured by Fritsch Co., Ltd.), and was stirred at 25°C at a rotation speed of 300 rpm for 60 minutes. Thereafter, 7.0 g of LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (NMC) was put as a positive electrode active material, and the container was assembled in the planetary ball mill P-7 in the same manner, and was further mixed at a rotation speed of 100 rpm at 25°C for 5 minutes, and thus the positive electrode compositions were prepared, respectively.​​

[0557] (Production of positive electrode sheet for all-solid-state secondary battery)

[0558] The positive electrode composition obtained above was coated on an aluminum foil (positive electrode current collector) having a thickness of 20 μm using a baking applicator (trade name: SA-201, manufactured by TESTER SANGYO CO,. LTD.), and the positive electrode composition was dried (removal of dispersion medium) by heating at 100°C for 2 hours. Then, using a hot press, the dried positive electrode composition was pressed at 25°C (10 MPa, 1 minute) to produce a positive electrode sheet for all-solid-state secondary battery having a positive electrode active material layer with a thickness of 80 μm.

[0559] In the production of the all-solid-state secondary battery No. 119, instead of the negative electrode sheet for all-solid-state secondary battery No. 137 having a solid electrolyte layer, the negative electrode sheet for all-solid-state secondary battery indicated by No. shown in the column of "electrode active material layer" of Table 4-2 having a solid electrolyte layer was used, and otherwise, the all-solid-state secondary batteries (full cells) Nos. 120 to 136, c106 to cl 10, and cl 14 to cl 16 were produced in the same manner as in the production of the all-solid-state secondary battery No. 119.

[0560] < Evaluation 3: Cycle characteristics test >

[0561] For each of the produced all-solid-state secondary batteries, the discharge capacity maintenance rate was measured by a charge / discharge evaluation device TOSCAT-3000 (trade name, manufactured by TOYO SYSTEM Co., Ltd.).

[0562] Specifically, each of the all-solid-state secondary batteries 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. This was taken as one charge / discharge cycle, and three charge / discharge cycles were repeated under the same conditions to initialize it. Then, the above charge / discharge cycle was repeated, and the discharge capacity of each of the all-solid-state secondary batteries was measured using the charge / discharge evaluation device: TOSCAT-3000 (trade name) each time the charge / discharge cycle was performed.

[0563] When the discharge capacity of the first cycle of charge and discharge after the initialization (initial discharge capacity) is set to 100%, the number of cycles at which the discharge capacity maintenance rate (discharge capacity relative to the initial discharge capacity) reaches 80% is evaluated as the battery performance (cycle characteristics) by including in which of the following evaluation standards. In this test, the higher the evaluation standard, the more excellent the battery performance (cycle characteristics), and the initial battery performance can be maintained even if the charge and discharge are repeated a plurality of times (even if used for a long period of time). The pass level of this test is "B" or more for the all-solid-state secondary batteries No. 101 to 118, c101 to c105, and c111 to c113 using the positive electrode sheet for all-solid-state secondary batteries shown in Table 4-1, and "C" or more for the all-solid-state secondary batteries No. 119 to 136, c106 to c110, and c114 to c116 using the negative electrode sheet for all-solid-state secondary batteries shown in Table 4-2.

[0564] In addition, the initial discharge capacity of each of the all-solid-state secondary batteries No. 101 to 136 showed a sufficient value for functioning as an all-solid-state secondary battery.

[0565] Evaluation standards

[0566] A: 500 cycles or more

[0567] B: 250 cycles or more and less than 500 cycles

[0568] C: 150 cycles or more and less than 250 cycles

[0569] D: 80 cycles or more and less than 150 cycles

[0570] E: less than 80 cycles

[0571] Evaluation 4: Ion conductivity measurement

[0572] The ion conductivity of each of the manufactured all-solid-state secondary batteries was measured. Specifically, for each of the all-solid-state secondary batteries, in a thermostat at 30°C, using a 1255B FREQUENCY RESPONSE ANALYZER (trade name, manufactured by SOLARTRON), the alternating current impedance was measured up to a voltage amplitude of 5 mV and a frequency of 1 MHz to 1 Hz. Thereby, the resistance in the layer thickness direction of the sample for ion conductivity measurement was calculated, and the ion conductivity was calculated by the following equation (1).

[0573] Equation (1): Ion conductivity σ (mS / cm) =

[0574] 1000 x sample layer thickness (cm) / [resistance (Ω) x sample area (cm 2 )]

[0575] In formula (1), the sample layer thickness is a value obtained by measuring before the laminate 12 is put into the 2032-type button cell 11 and subtracting the thickness of the current collector (total thickness of the solid electrolyte layer and the electrode active material layer). The sample area is the area of a circular plate-shaped sheet having a diameter of 14.5 mm.

[0576] Determination was made as to whether the obtained ion conductivity σ was included in which one of the following evaluation criteria.

[0577] In the ion conductivity σ in this experiment, the evaluation criteria "D" or more was the pass level.

[0578] Evaluation Criteria

[0579] A: 0.60 < σ

[0580] B: 0.50 < σ < 0.60

[0581] C: 0.30 < σ < 0.50

[0582] D: 0.20 < σ < 0.30

[0583] E: σ < 0.20

[0584] [Table 4-1]

[0585]

[0586] [Table 4-2]

[0587]

[0588] From the results shown in Table 3 and Tables 4-1 and 4-2, the following can be known.

[0589] It was known that the dispersion stability of the inorganic solid electrolyte composition containing no component constituting the polymer binder prescribed in the present application was poor, and the layer formed using these compositions showed a large coating thickness unevenness, and thus the handleability was also poor. Also, the all-solid-state secondary battery using these compositions having poor dispersion stability and handleability did not show sufficient ion conductivity and cycle characteristics.

[0590] On the other hand, the inorganic solid electrolyte-containing composition containing the components constituting the polymer binder prescribed in the present application has both the dispersion stability and the handling property at a high level. It is known that by using the inorganic solid electrolyte-containing composition for forming a constituent layer of a full solid-state secondary battery, a constituent layer having a flat surface and low resistance can be formed, and the obtained full solid-state secondary battery can achieve excellent cycle characteristics and high ionic conductivity. It is considered that the above effects of the present application are because the soluble polymer prescribed in (C1) or (C2) prescribed in the present application is dissolved in the inorganic solid electrolyte-containing composition to exhibit excellent dispersion characteristics, and on the other hand, the solid particles can be bound to each other while suppressing the increase in the interfacial resistance by forming a polymer binder in the constituent layer through a chemical reaction.

[0591] The full solid-state secondary battery of the present application exhibits the above excellent characteristics, and thus exhibits excellent cycle characteristics even under high-speed charge and discharge conditions.

[0592] The present application has been described together with its embodiments, but the present application is not limited in any detail of the description unless specifically indicated, and should be interpreted broadly as long as it does not depart from the idea and scope of the present application shown in the claims.

[0593] This application claims priority based on Japanese Patent Application No. 2020-061882 filed on March 31, 2020 in Japan, which is hereby incorporated by reference, and the content thereof is incorporated into the present specification as a part thereof.

[0594] Explanation of symbols

[0595] 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 site, 10 - full solid-state secondary battery, 11 - 2032 type coin cell case, 12 - full solid-state secondary battery laminate, 13 - coin-type full solid-state secondary battery, TP - test piece.

Claims

1. A composition containing an inorganic solid electrolyte, comprising: Inorganic solid electrolytes possessing conductivity of ions belonging to Group 1 or Group 2 of the periodic table. The following components constitute the polymer adhesive, and Dispersion medium, in, The components constituting the polymer adhesive include at least one polymer specified in (C1) and (C2) below. (C1) Soluble polymer C1-I having at least one functional group or partial structure selected from group (I) below and soluble polymer C1-II having at least one functional group or partial structure selected from group (II) below, (C2) A soluble polymer C2 having at least one functional group or partial structure selected from each of Group (I) and Group (II) below, respectively. The soluble polymer C1-I and the soluble polymer C1-II can chemically react with at least one functional group or part of the structure selected from group (I) and at least one functional group or part of the structure selected from group (II) to form the polymer adhesive. The soluble polymer C2 can form the polymer adhesive by chemically reacting with at least one functional group or part of the structure selected from group (I) below through its own presence. Group (I): hydroxyl, primary or secondary amino, 1,3-dicarbonyl structure. Group (II): End-capped isocyanate group, borate group or hypoborate group, borate group or hypoborate group, anhydride structure. The total content of the soluble polymer C1-I and the soluble polymer C1-II in the inorganic solid electrolyte composition is 0.1-10.0% by mass of the solid component (100% by mass). The content of the soluble polymer C2 in the inorganic solid electrolyte composition is 0.1% to 10.0% by mass of the solid component. The mass-average molecular weights of the soluble polymers C1-I, C1-II, and C2 are each between 15,000 and 5,000,000.

2. The inorganic solid electrolyte composition according to claim 1, wherein, At least one of the soluble polymers has more than 50% by mass of a component derived from (meth)acrylic acid monomers or vinyl monomers.

3. The inorganic solid electrolyte composition according to claim 1, wherein, The inorganic solid electrolyte is a sulfide-based inorganic solid electrolyte.

4. The inorganic solid electrolyte composition according to claim 1, wherein, The dispersion medium contains at least one selected from ketone compounds, aliphatic compounds, and ester compounds.

5. The inorganic solid electrolyte composition according to claim 1, wherein it contains an active substance.

6. The inorganic solid electrolyte composition according to claim 1, wherein it contains a conductive additive.

7. A sheet for an all-solid-state secondary battery, having a layer composed of an inorganic solid electrolyte composition as described in any one of claims 1 to 6.

8. An all-solid-state secondary battery, comprising sequentially 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 an inorganic solid electrolyte composition as described in any one of claims 1 to 6.

9. A method for manufacturing a sheet for an all-solid-state secondary battery, wherein the inorganic solid electrolyte composition according to any one of claims 1 to 6 is used to form a film.

10. A method for manufacturing an all-solid-state secondary battery, wherein the all-solid-state secondary battery is manufactured by the manufacturing method described in claim 9.

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