Binder composition for secondary battery, solid electrolyte-containing composition for secondary battery, sheet for all-solid-state secondary battery, and all-solid-state secondary battery

Abstract

Provided are: a binder composition which is for a secondary battery, which contains a metal element-containing component having a particle diameter of 10 μm or less and contains a binder constituted by a polymer having less than 30 mass% of constituent components derived from an ethylenically unsaturated carboxylic acid with respect to all constituent components of the polymer, and in which the contained amount of the metal element-containing component is 1.0×10-3 ppm to 1.0×104 ppm; a solid electrolyte-containing composition which is for a secondary battery, which contains said binder composition and an inorganic solid electrolyte, and in which the contained amount of the metal element-containing component is in a specific range; a sheet which is for an all-solid-state secondary battery and which has a layer constituted by said composition; and an all-solid-state secondary battery.

Description

Binder composition for secondary battery, solid electrolyte-containing composition for secondary battery, sheet for all-solid-state secondary battery, and all-solid-state secondary battery

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

[0002] A nonaqueous electrolyte secondary battery (also referred to as a nonaqueous secondary battery) is a storage battery that has a negative electrode, a positive electrode, and a nonaqueous electrolyte between the negative and positive electrodes. It is capable of charging and discharging by the reciprocating movement of specific metal ions, such as lithium ions, between the two electrodes. Such nonaqueous secondary batteries include nonaqueous electrolyte secondary batteries using organic electrolytes and all-solid-state secondary batteries using solid electrolytes. In particular, all-solid-state secondary batteries, in which the negative electrode, electrolyte, and positive electrode are all solid, can significantly improve the safety and reliability issues associated with nonaqueous electrolyte secondary batteries. They are also believed to enable longer battery life. Furthermore, all-solid-state secondary batteries can be configured with electrodes and solid electrolytes directly arranged in series. Therefore, all-solid-state secondary batteries can achieve higher energy densities than nonaqueous electrolyte secondary batteries, and are expected to be used in electric vehicles, large-scale storage batteries, and other applications.

[0003] In nonaqueous electrolyte secondary batteries and all-solid-state secondary batteries, electrode layers (negative electrode active material layer, positive electrode active material layer), solid electrolyte layers, and the like (collectively referred to as "constituent layers") are typically formed using compositions (constituent layer-forming materials) containing raw material compounds constituting each layer, such as active materials and inorganic solid electrolytes, in consideration of improving productivity. When forming constituent layers using these solid particles (active materials, conductive additives, inorganic solid electrolytes, and the like), binders play an important role in firmly binding the solid particles together and achieving desired battery characteristics. For this reason, various studies have been conducted on binders themselves or binder compositions. For example, binders and binder compositions with reduced amounts or contents of metal impurities that cause deterioration of battery characteristics, short circuiting, and the like have been studied.

[0004] Specifically, Patent Document 1 describes a "binder composition for secondary batteries having a content of particulate metal components with a particle size of 20 μm or more of 10 ppm or less" obtained by a specific manufacturing method including a particulate metal removal step of removing particulate metal components. Patent Document 2 also describes a "binder for secondary battery electrodes containing a crosslinked polymer having a carboxyl group or a salt thereof, wherein the crosslinked polymer or salt thereof contains 30% by mass or more and 100% by mass or less of structural units derived from ethylenically unsaturated carboxylic acid monomers, and the crosslinked polymer or salt thereof has a polyvalent metal ion content of 100 ppm or less." Patent Document 3 also describes a "binder composition for non-aqueous secondary battery positive electrodes containing a first binder, the binder comprising iron and at least one of ruthenium and rhodium, wherein the total content of the iron, ruthenium, and rhodium is 5 × 10 per 100 parts by mass of the first binder." －３ Furthermore, Patent Document 4 describes a binder composition for producing a positive electrode for a secondary battery, which comprises a hydrogenated polymer obtained by hydrogenating a polymer containing a conjugated diene monomer unit and a nitrile group-containing monomer unit, wherein the amount of a platinum group element in the binder composition is 8×10 or less with respect to 100 parts by weight of the hydrogenated polymer contained in the binder composition. －４ parts by weight or less, and the hydrogenated polymer has a Wallace plasticity of 30 to 97 at 25°C.

[0005] International Publication No. 2010 / 032784 International Publication No. 2020 / 090694 International Publication No. 2016 / 103730 Japanese Patent Application Laid-Open No. 2013-157086

[0006] As described above, the constituent layers of nonaqueous electrolyte secondary batteries and all-solid-state secondary batteries are formed from solid particles, which restricts the interfacial contact between the solid particles, resulting in increased interfacial resistance. Furthermore, because binders typically have low electronic and ionic conductivity, the inclusion of a binder further increases resistance. Such increased interfacial resistance leads to a deterioration in the battery characteristics of the secondary battery, for example, an increase in battery resistance (a decrease in ionic conductivity). In particular, in recent years, rapid progress has been made in the development of practical all-solid-state secondary batteries, and accordingly, secondary batteries with further reduced battery resistance are in demand. However, Patent Documents 1 to 4 do not address the reduction of interfacial resistance and battery resistance.

[0007] An object of the present invention is to provide a binder composition for a secondary battery that can further reduce the battery resistance of the secondary battery. Another object of the present invention is to provide a solid electrolyte-containing composition for a secondary battery that contains the binder composition for a secondary battery, and further to provide a sheet for an all-solid-state secondary battery and an all-solid-state secondary battery that have a constituent layer formed using the solid electrolyte-containing composition for a secondary battery.

[0008] The present inventors have conducted extensive research into binder compositions (hereinafter, simply referred to as binder compositions) containing a binder that binds together solid particles that form the constituent layers of secondary batteries. As a result, they have found that the binder is composed of a polymer having a content of less than 30 mass % of a constituent component derived from an ethylenically unsaturated carboxylic acid in all constituent components, and that a metal element-containing component having a particle size of 10 μm or less is added to the binder in an amount of 1.0 × 10 －３ ~1.0 x 10 ４ It was found that by using the binder in combination at a ratio of 100 ppm, the binder can be appropriately agglomerated to bind the solid particles while ensuring direct interfacial contact between the solid particles, and as a result, a constituent layer can be formed in which an increase in resistance is highly suppressed. The present invention was completed after further investigations based on these findings.

[0009] That is, the above-mentioned problems have been solved by the following means: <1> A binder composition for a secondary battery containing a metal element-containing component having a particle size of 10 μm or less and a polymer binder, wherein the content of the metal element-containing component in the composition is 1.0×10 －３ ~1.0 x 10 ４ <2> The binder composition for secondary batteries according to <1>, wherein the metal element-containing component contains at least one metal element selected from Al, B, Ga, In, Si, and Ge. <3> The binder composition for secondary batteries according to <1> or <2>, wherein the polymer forming the polymer binder contains a component having at least one polar functional group selected from the following functional group group (a): <Polar functional group (a)> A sulfonic acid group, a phosphoric acid group, a phosphonic acid group, a hydroxy group, a carboxy group other than the carboxy group derived from the ethylenically unsaturated carboxylic acid, an oxetane group, an epoxy group, a dicarboxylic acid anhydride group, a thiol group, an ether group, a thioether group, a thioester group, a fluoroalkyl group, or a salt thereof. <4> The binder composition for secondary batteries according to any one of <1> to <3>, wherein the polymer forming the polymer binder has a carboxy group. <5> The binder composition for a secondary battery according to any one of <1> to <4>, wherein the polymer forming the polymer binder contains a component having a carboxy group in an amount of 0.1 to 10 mass % based on the total components of the polymer. <6> The weight-average molecular weight of the polymer binder is 1.0 × 10 ４ ~1.0 x 10 ６ <7> A solid electrolyte-containing composition for a secondary battery, comprising the binder composition for a secondary battery according to any one of the above items <1> to <6> and an inorganic solid electrolyte having ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, wherein the content of the metal element-containing component in the solid electrolyte-containing composition for a secondary battery is 1.0 × 10 －３ ~1.0 x 10 ４<10> A sheet for an all-solid-state secondary battery having a layer constituted by the solid electrolyte-containing composition for a secondary battery according to any one of <7> to <9> above. <11> An all-solid-state secondary battery comprising a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order, 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 constituted by the solid electrolyte-containing composition for a secondary battery according to any one of <7> to <9>. <12> An all-solid-state secondary battery including a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order, wherein at least one of the positive electrode active material layer and the negative electrode active material layer is an active material layer made of the solid electrolyte-containing composition for secondary batteries according to <8> or <9>.

[0010] The binder composition for secondary batteries and the solid electrolyte-containing composition for secondary batteries of the present invention can be used as materials for forming constituent layers to form constituent layers that highly suppress an increase in resistance, thereby realizing a secondary battery that exhibits low resistance (high ionic conductivity). Furthermore, by incorporating the sheet for all-solid-state secondary batteries as a constituent layer of a secondary battery, a secondary battery that exhibits low resistance can be realized. Furthermore, the secondary battery of the present invention exhibits low resistance. The above and other features and advantages of the present invention will become more apparent from the following description, with reference to the accompanying drawings as appropriate.

[0011] Fig. 1 is a longitudinal sectional view schematically showing an all-solid-state secondary battery according to a preferred embodiment of the present invention, and Fig. 2 is a longitudinal sectional view schematically showing a coin-type all-solid-state secondary battery fabricated in Examples.

[0012] In the present invention, when describing the content, physical properties, etc. of a component by indicating a numerical range, if the upper and lower limits of the numerical range are described separately, any of the upper and lower limits can be appropriately combined to form a specific numerical range. On the other hand, when describing multiple numerical ranges represented using "to", the upper and lower limits forming the numerical range are not limited to the specific combinations written before and after "to" as a specific numerical range, but can be any numerical range obtained by appropriately combining the upper and lower limits of each numerical range. Note that in the present invention, a numerical range represented using "to" means a range that includes the numerical values ​​written before and after "to" as the upper and lower limits. In the present invention, when a compound is referred to (for example, when "compound" is added to the end), it is used to mean not only the compound itself, but also its salts and ions. Furthermore, it is meant to include derivatives that have been partially modified, such as by introducing a substituent, within a range that does not impair the effects of the present invention. In the present invention, "(meth)acrylic" means one or both of acrylic and methacrylic. In the present invention, substituents, linking groups, etc. (hereinafter referred to as substituents, etc.) that are not specified as substituted or unsubstituted mean that the group may have an appropriate substituent. Therefore, even when simply described as a YYY group in the present invention, this YYY group includes not only an embodiment in which it has no substituent, but also an embodiment in which it further has a substituent. This also applies to compounds in which it is not specified as substituted or unsubstituted. Preferred substituents include, for example, the substituent Z described below.

[0013] In the present invention, the term "polymer" refers to a polymer and is synonymous with a so-called polymer compound. Furthermore, the term "polymer binder" (also simply referred to as "binder") refers to a binder composed of a polymer, and includes both the polymer itself and binders composed (formed) containing a polymer. In the present invention, the term "main chain of a polymer" refers to a linear molecular chain in which all other molecular chains constituting the polymer or polymer chain can be considered as branched chains or pendant groups relative to the main chain. While this depends on the weight-average molecular weight of the branched chains considered as branched chains or pendant groups, typically, the longest chain among the molecular chains constituting the polymer or polymer chain is the main chain. However, terminal groups at the ends of the polymer or polymer chain are not included in the main chain. Furthermore, the term "side chain of a polymer" refers to branched chains other than the main chain, including short and long chains.

[0014] [Binder Composition for Secondary Batteries] The binder composition for secondary batteries of the present invention contains a specific content of a metal element-containing component having a particle size of 10 μm or less and a specific polymer binder. This binder composition is used as a binder for forming a constituent layer in a constituent layer-forming material, for example, a solid electrolyte-containing composition for secondary batteries, to form a constituent layer in which an increase in resistance is highly suppressed, and a sheet for all-solid-state secondary batteries having a constituent layer with low resistance (high ionic conductivity), a secondary battery exhibiting low resistance (high ionic conductivity), etc. can be produced.

[0015] The above-mentioned effects of the binder composition of the present invention were discovered as a result of various studies on binder compositions, and although the details of the reasons for this are not yet clear, it is believed to be as follows: In other words, in the binder composition, the polymer binder coexists with a metal element-containing component having a specific particle size at a specific content, thereby causing interactions (e.g., electrostatic attraction, intermolecular force, coordination force, etc.) with the metal element-containing component, thereby enhancing cohesion. As a result, it is believed that the polymer binder does not form excessively large aggregates that cause precipitation, but forms appropriately aggregated aggregates of an appropriate size. When these aggregates bind solid particles, they do not hinder the direct contact between the solid particles, ensuring a direct contact area and allowing the solid particles to be bound while suppressing an increase in interfacial resistance.

[0016] The binder composition of the present invention is preferably a non-aqueous composition. In the present invention, the non-aqueous composition includes not only an embodiment that does not contain water, but also an embodiment in which the water content (also referred to as moisture content) is preferably 500 ppm or less. In a non-aqueous composition, the water content is more preferably 200 ppm or less, even more preferably 100 ppm or less, and particularly preferably 50 ppm or less. When the binder composition is a non-aqueous composition, deterioration of the inorganic solid electrolyte in the solid electrolyte-containing composition for secondary batteries described below can be suppressed. The water content refers to the amount of water contained in the binder composition (mass ratio relative to the binder composition), and specifically refers to the value measured by filtering through a 0.02 μm membrane filter and using Karl Fischer titration.

[0017] The binder composition of the present invention may contain a polymer binder and a metal element-containing component, and may contain raw material compounds for forming constituent layers such as an inorganic solid electrolyte and an active material. However, since the binder composition of the present invention is used as a preparation material for the solid electrolyte-containing composition for a secondary battery of the present invention, which is a constituent layer-forming material, it preferably does not contain the raw material compounds for forming the above-mentioned constituent layers. In the present invention, "not containing raw material compounds" does not exclude raw material compounds that are inevitably contained, but means that the raw material compounds may be contained within a range that does not impair the effects of the present invention, for example, a content of 5 mass% or less in the binder composition.

[0018] The binder composition of the present invention is preferably used as a material for forming a constituent layer of a secondary battery, particularly as a material for preparing a solid electrolyte-containing composition for a secondary battery, and also as a material for forming a sheet for an all-solid-state secondary battery and a constituent layer of an all-solid-state secondary battery.

[0019] Components contained in the binder composition of the present invention and components that may be contained therein will be described below.

[0020] <Metal Element-Containing Component> The binder composition of the present invention contains a metal element-containing component having a particle size of 10 μm or less. In the present invention, the metal element-containing component may be any component that has the property of interacting with the polymer binder (the polar portion thereof) described below, and examples thereof include compounds that have the function of appropriately promoting and forming self-aggregation of the coexisting polymer binder. Meanwhile, this metal element-containing component is used as a material for forming a constituent layer of a secondary battery, but does not contain an active material, an inorganic solid electrolyte, a conductive additive, a lithium salt, etc.

[0021] Examples of such metal element-containing components include simple metal elements (simple metals) and compounds containing one or more metal elements. In the present invention, the term "metal element" encompasses so-called metalloid elements, specifically metal elements belonging to Groups 1 to 14 of the periodic table (excluding hydrogen), as well as metalloid elements belonging to any of Groups 13 to 17 of the periodic table. Examples of metalloid elements include boron, silicon, germanium, antimony, bismuth, selenium, tellurium, and the like. The metal element contained in the metal element-containing component is not particularly limited, but is preferably a metal element or metalloid element belonging to any of Groups 2 to 14, more preferably a metal element or metalloid element belonging to Group 13 or 14, and even more preferably one or more elements selected from aluminum (Al), boron (B), gallium (Ga), indium (In), silicon (Si), and germanium (Ge). The number of types of metal elements contained in the metal element-containing component may be one or two or more, and the upper limit may be 30, but is preferably 1 to 4.

[0022] The metal element-containing component may be a component (compound) formed solely from the metal element, or a component (compound) formed from the metal element and other elements. Examples of components formed from the metal element and other elements include inorganic or organic compounds containing the metal element. Specific examples include oxides of the metal element, halides of the metal element, hydroxides of the metal element, inorganic or organic acid salts of the metal element, and metal salts or esters of boric acid. Examples also include organometallic compounds such as alkylated or arylated metals, metal alkoxides, and metal aryloxides. Examples of inorganic acids include, but are not limited to, hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, boric acid, and silicic acid (including aluminosilicate). Examples of organic acids include, but are not limited to, organic carboxylic acids such as formic acid and acetic acid, organic sulfonic acids such as paratoluenesulfonic acid, organic phosphonic acids such as alkylphosphonic acids, and phosphinic acids. When the above oxides contain two or more metal elements, they are also referred to as composite oxides. The metal element-containing component is preferably a non-metallic component such as a simple metal element or an alloy, more preferably a component (compound) formed of a metal element and another element, more preferably a (composite) oxide of a metal element, an inorganic acid salt or an organic acid salt of a metal element, a metal element salt of boric acid, an organometallic compound, etc., and particularly preferably an oxide of a metal element, an aluminosilicate or organic acid salt of a metal element, an organometallic compound, etc., and most preferably the metal element contained in these compounds contains one or more of the above-mentioned preferred metal elements.

[0023] More specifically, examples of compounds containing Al element include aluminum metal, aluminum oxide (alumina), aluminum hydroxide, trialkoxyaluminum, aluminosilicate, and aluminum halides. Examples of compounds containing B element include boron oxide, boron halides, boron alkylates, and trialkyl borates. Examples of compounds containing Ga element include gallium metal, gallium oxide, trialkoxygallium, and gallium halides. Examples of compounds containing In element include indium metal, indium oxide, alkoxyindium, and indium halides. Examples of compounds containing Si element include silicon oxide (silica), alkoxysilicon, silicon halides, and siloxane compounds. The siloxane compound may be a chain compound or a cyclic compound (cyclic siloxane compound). A siloxane compound generally comprises a siloxane unit: -Si(R ２ )O-unit, and the number of siloxane units is determined appropriately. For example, in a cyclic siloxane compound, the number can be 3 to 10, and preferably 3 to 6. R in the siloxane unit can be an alkyl group, aryl group, heterocyclic group, alkoxy group, aryloxy group, heterocyclic oxy group, etc., but an alkyl group is preferred, and an alkyl group having 1 to 3 carbon atoms is more preferred. The two R in one siloxane unit may be different, but are preferably the same. The groups that can be used as R are not particularly limited, and examples include groups corresponding to the substituent Z described below.

[0024] Specific examples of the metal element-containing component include the compounds used in the examples described below, but the present invention is not limited to these. Among these, alumina, silica, and aluminosilicates of one or more metal elements are preferred.

[0025] The metal element-containing component may be present as a simple metal or a compound itself in the coexistence with the polymer binder, for example, in the binder composition, the solid electrolyte-containing composition for a secondary battery described later, and the constituent layer, or the metal element-containing component may be decomposed, dissociated, or the like and be present as a metal ion or the like.

[0026] The metal element-containing component may be present in particulate form in the presence of a polymer binder, or may be present in a dissolved state in a dispersion medium or the like. In the present invention, when the metal element-containing component is present in a dissolved state, its particle size cannot be specified, but is conveniently designated as "0 μm." That is, a metal element-containing component having a particle size of 10 μm or less includes a particulate metal element-containing component having a particle size of more than 0 μm but not more than 10 μm, and a dissolved metal element-containing component whose particle size is considered to be 0 μm. In the present invention, the metal element-containing component is preferably present in a dissolved state. The presence of the metal element-containing component in a dissolved state can be confirmed by measuring using a light scattering particle size distribution analyzer and finding that no particle size distribution is observed (the presence of particles cannot be confirmed).

[0027] In the binder composition, the particle size of the metal element-containing component is 10 μm or less. By having a particle size of 10 μm or less, the cohesiveness of the polymer binder is increased while suppressing the formation of excessive aggregates (sedimentation of the polymer binder), thereby reducing the area of ​​contact with the solid particles, and a constituent layer in which the solid particles are bound together can be formed while suppressing an increase in resistance. In order to further suppress an increase in resistance, the particle size of the metal element-containing component is preferably 6 μm or less, more preferably 3 μm or less, and even more preferably 1 μm or less. On the other hand, when the metal element-containing component is present in particulate form in the binder composition, the lower limit of the particle size is preferably greater than 0 μm.

[0028] The particle size of the metal element-containing component is the particle size value obtained by filtering the binder composition using a magnetic filter, etc., and measuring the particles obtained using an optical microscope. The particle size of the metal element-containing component in the binder composition can be adjusted by an appropriate method, for example, by adjusting (changing) the particle size of the metal element-containing component used in preparing the binder composition, the preparation conditions of the binder composition (mixing conditions, etc.), and further the content of the metal element-containing component, etc.

[0029] The binder composition may contain one or two metal element-containing components. Content C of the metal element-containing component in the binder composition ＭＢ is 1.0 x 10 －３ ~1.0 x 10 ４ In the present invention, ppm is based on mass. Content C of metal element-containing component ＭＢ When the content C of the metal element-containing component is in this range, it is possible to form a constituent layer that suppresses an increase in resistance without excessively covering the solid particles while appropriately increasing the cohesion of the polymer binder. In addition, it is possible to suppress the deterioration or loss of battery function due to the presence of the metal element-containing component. In terms of being able to further suppress an increase in resistance while maintaining the battery function, the content C of the metal element-containing component is ＭＢ is 1.0 x 10 －１ ~1.0 x 10 ３ is preferably 1.0 to 1.0 × 10 ３ More preferably, it is 5 to 5.0 × 10 ２ ppm is more preferable, and 10 to 1.0 x 10 ２ It is particularly preferable that the content of the metal element-containing component is 10 to 50 ppm, and most preferable that the content of the metal element-containing component is 10 to 50 ppm. ＭＢ can be calculated from the amount of the metal element-containing component used in preparing the binder composition, or from the results of elemental analysis measured by inductively coupled plasma mass spectrometry (ICP-MS). ＭＢ In the case where the metal element-containing component is present after decomposition, etc., the total content includes the content of the component present after decomposition, etc.

[0030] In the binder composition, the content C of the polymer binder described later ＰＢ Content C of metal element-containing component relative to ＭＢ The ratio [C ＭＢ / C ＰＢ ] is not particularly limited and can be determined appropriately. For example, in terms of being able to effectively suppress an increase in resistance, this ratio [C ＭＢ / C ＰＢ ] is 1.0 × 10 －８ ~1.0 x 10 －１ can be expressed as 1.0 × 10 －７ ~1.0 x 10 －２ It is preferable that the －６ ~1.0 x 10 －３ More preferably, it is 5.0 × 10 －５ ~1.0 x 10 －３ More preferably, it is 1.0 × 10 －４ ~1.0 x 10 －３ It is particularly preferable that －４ ~5.0 x 10 －４ It is most preferable that:

[0031] In the binder composition, the metal element-containing component may contain one having a particle size of more than 10 μm within a range that does not impair the effects of the present invention, but it is preferable that the binder composition does not contain a metal element-containing component having a particle size of more than 10 μm. In the present invention, the range that does not impair the effects of the present invention is not particularly limited, but for example, the content of the metal element-containing component having a particle size of more than 10 μm in the binder composition is 1.0×10 －１ This means that the concentration is less than ppm.

[0032] <Polymer Binder> The polymer binder contained in the binder composition of the present invention is a polymer binder formed by incorporating a polymer, and this polymer (also referred to as a binder-forming polymer) is a polymer having a component derived from an ethylenically unsaturated carboxylic acid in a content of less than 30 mass% of all the components of the polymer. A polymer binder formed from a polymer having the component MA derived from an ethylenically unsaturated carboxylic acid in the above content interacts with a coexisting metal element-containing component to exhibit appropriate cohesion. As a result, the binder composition of the present invention can form a component layer while suppressing an increase in resistance. The binder-forming polymer may have one or more types of component MA.

[0033] In the present invention, "ethylenically unsaturated carboxylic acid" refers to (meth)acrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, (meth)acrylamidoalkylcarboxylic acid, ethylenically unsaturated monomers having a carboxy group, or alkali-neutralized products thereof, and specific examples include the "ethylenically unsaturated carboxylic acid monomer" described in paragraph

[0036] of Patent Document 2. The content of the constituent MA in all constituent components of the binder-forming polymer may be less than 30% by mass, but from the viewpoint of further suppressing an increase in resistance, it is preferably 0 to 20% by mass, more preferably 0.01 to 10% by mass, and even more preferably 0.1 to 5% by mass.

[0034] (Polar Functional Group-Containing Constituent MC) The binder-forming polymer preferably contains one or more constituents MC (also referred to as polar functional group-containing constituents) having at least one polar functional group selected from the functional group group (a) below. When the binder-forming polymer contains the polar functional group-containing constituent MC, the cohesiveness of the polymer binder can be further enhanced and solid particles can be firmly bound. The polar functional group-containing constituent MC may contain at least one (one type) polar functional group, and typically, it preferably contains one to three types of polar functional groups. The number of polar functional groups contained in the binder-forming polymer is not particularly limited and is determined appropriately depending on the number of polar functional groups contained in the polar functional group-containing constituent MC itself, the content of the polar functional group-containing constituent MC, the molecular weight of the binder-forming polymer, and the like. The polar functional group-containing constituent MC may contain a polar functional group, and examples thereof include constituents derived from polycondensable compounds having at least one (one type) polar functional group selected from the functional group group (a) below. The polycondensable compound is preferably, for example, a compound having a polycondensable group, a polar functional group or a substituent having a polar functional group, and, if appropriate, a linking group that links the polycondensable group and the substituent.

[0035] The polycondensable group is appropriately determined depending on the main chain structure of the binder-forming polymer. For example, in the case of a step-polymerization polymer described below, a condensable functional group is selected, and in the case of a chain-polymerization polymer, a polymerizable group (ethylenically unsaturated group) is selected. The substituent before being substituted with the polar functional group is not particularly limited, and examples thereof include groups selected from the substituent Z described below, with alkyl groups being preferred, and alkyl groups having 1 to 6 carbon atoms being more preferred. The linking group is not particularly limited, and examples thereof include alkylene groups (preferably having 1 to 12 carbon atoms, more preferably having 1 to 6 carbon atoms, and even more preferably having 1 to 3 carbon atoms), alkenylene groups (preferably having 2 to 6 carbon atoms, and more preferably having 2 to 3 carbon atoms), arylene groups (preferably having 6 to 24 carbon atoms, and more preferably having 6 to 10 carbon atoms), oxygen atoms, sulfur atoms, imino groups (-NR Ｎ -:R Ｎrepresents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms. ), a carbonyl group, a phosphate linking group (-O-P(OH)(O)-O-), a phosphonate linking group (-P(OH)(O)-O-), or a group relating to a combination thereof. The linking group is preferably an alkylene group, an arylene group, a carbonyl group, an oxygen atom, a sulfur atom, or an imino group, or a group relating to a combination thereof, more preferably an alkylene group, an arylene group, a carbonyl group, an oxygen atom, a sulfur atom, or an imino group, or a group relating to a combination thereof, and even more preferably a -CO-O- group. The number of atoms constituting the linking group is preferably 1 to 36, more preferably 1 to 24, and even more preferably 1 to 12. The number of linking atoms of the linking group is preferably 12 or less, more preferably 10 or less, and particularly preferably 8 or less. The lower limit is 1 or more. The number of linking atoms refers to the minimum number of atoms connecting the specified structural moieties. For example, in the case of a —CO—O— group, the number of atoms constituting the linking group is three, but the number of linking atoms is two.

[0036] <Functional Group (a)> Sulfonic acid group (sulfo group), phosphoric acid group (phosphoryl group), phosphonic acid group, carboxy group other than carboxy group derived from ethylenically unsaturated carboxylic acid, hydroxy group, oxetane group, epoxy group, dicarboxylic acid anhydride group, thiol group (sulfanyl group), ether group, thioether group, thioester group, fluoroalkyl group, and salts thereof

[0037] The sulfonic acid group, phosphoric acid group, phosphonic acid group, etc. included in the functional group group (a) are not particularly limited, but each has the same meaning as the corresponding group of the substituent Z described below. The dicarboxylic acid anhydride group is not particularly limited, but includes a group obtained by removing one or more hydrogen atoms from a dicarboxylic acid anhydride, and the constituent component itself formed by copolymerization of a polymerizable dicarboxylic acid anhydride, as well as a group formed by cleavage of the anhydride group upon reaction of a dicarboxylic acid anhydride with an active hydrogen compound. The group obtained by removing one or more hydrogen atoms from a dicarboxylic acid anhydride is preferably a group obtained by removing one or more hydrogen atoms from a cyclic dicarboxylic acid anhydride. Examples of dicarboxylic acid anhydrides include acyclic dicarboxylic acid anhydrides such as acetic anhydride, propionic anhydride, and benzoic anhydride, and cyclic dicarboxylic acid anhydrides such as maleic anhydride, phthalic anhydride, fumaric anhydride, succinic anhydride, and itaconic anhydride. The polymerizable dicarboxylic acid anhydride is not particularly limited, but includes a dicarboxylic acid anhydride having an unsaturated bond in the molecule, preferably a polymerizable cyclic dicarboxylic acid anhydride. Specific examples include maleic anhydride, itaconic anhydride, etc. The active hydrogen compound is not particularly limited as long as it is a compound that reacts with a dicarboxylic acid anhydride group, and examples thereof include alcohol compounds, amine compounds, thiol compounds, etc. However, when a group formed by cleavage of an anhydride group upon reaction of a dicarboxylic acid anhydride with an active hydrogen compound corresponds to the above-mentioned ethylenically unsaturated carboxylic acid, it is interpreted as the above-mentioned ethylenically unsaturated carboxylic acid.

[0038] The ether group (-O-), thioether group (-S-), and thioester group (-CO-S-, -CS-O-, -CS-S-) each refer to the bond shown in parentheses. The terminal group bonded to these groups is not particularly limited, and examples thereof include groups selected from the substituent Z described below, such as alkyl groups. Although ether groups include carboxy groups, hydroxy groups, oxetane groups, epoxy groups, and dicarboxylic anhydride groups, the -O- groups contained therein are not considered ether groups. The same applies to thioether groups. A fluoroalkyl group is a group in which at least one hydrogen atom of an alkyl group or cycloalkyl group is substituted with a fluorine atom, and preferably has 1 to 20 carbon atoms, more preferably 2 to 15, and even more preferably 3 to 10 carbon atoms. The fluorine atoms on the carbon atoms may replace some or all of the hydrogen atoms (perfluoroalkyl group). Groups that can form salts, such as sulfonic acid groups (sulfo groups), phosphate groups, phosphonic acid groups, and carboxy groups, may form salts. Examples of the salt include various metal salts, ammonium or amine salts, etc. The polar functional group possessed by the polar functional group-containing component MC is preferably a carboxy group other than the carboxy group derived from an ethylenically unsaturated carboxylic acid, a hydroxy group, a phosphate group, an epoxy group, a dicarboxylic acid anhydride group, or an ether group, in terms of improving the cohesion of the polymer binder and further the adsorption (adhesion) to solid particles. When the polar functional group-containing component MC has two or more types of polar functional groups, the combination thereof is not particularly limited and can be determined appropriately. For example, a combination of a carboxy group other than the carboxy group derived from an ethylenically unsaturated carboxylic acid, a sulfonic acid group, or a phosphonic acid group with a hydroxy group, an oxetane group, an epoxy group, or an ether group is preferred, and a combination of a carboxy group other than the carboxy group derived from an ethylenically unsaturated carboxylic acid with a hydroxy group or an ether group is more preferred.

[0039] The polycondensable compound from which the polar functional group-containing constituent MC is derived is not particularly limited as long as it has the polar functional group, and examples thereof include compounds in which the polar functional group has been introduced into the raw material compounds constituting the binder-forming polymer, such as the (meth)acrylic compound (M1) or vinyl compound (M2) described below, or compounds in which the polar functional group has been introduced into these compounds (M1) or (M2).

[0040] (Other Constituents) The binder-forming polymer may contain other constituents in addition to the above-mentioned constituents. The other constituents may be any other constituents that do not fall under the category of the above-mentioned constituents, and examples thereof include constituents derived from the (meth)acrylic compound (M1) or vinyl compound (M2) described below. Among these, constituents derived from (meth)acrylic acid alkyl ester compounds are preferred, and constituents derived from acrylic acid ester compounds of long-chain alkyl groups are more preferred. The number of carbon atoms in the long-chain alkyl group can be, for example, 3 to 20, preferably 4 to 16, and more preferably 6 to 14.

[0041] The binder-forming polymer may contain one or more of the above-mentioned constituent components.

[0042] The binder-forming polymer preferably has a carboxy group, i.e., a component having a carboxy group, in that this can further enhance the cohesiveness of the polymer binder and can firmly bind the solid particles. Here, the component having a carboxy group refers to a component having a carboxy group in the structure of the binder-forming polymer, specifically, the component having a carboxy group among the components MA and the polar functional group-containing component MC.

[0043] The (total) content of the components having a carboxy group in all the components of the binder-forming polymer is determined appropriately taking into consideration the contents of the components MA and the polar functional group-containing component MC, the cohesiveness, etc., but from the viewpoints of being able to further enhance the cohesiveness of the polymer binder and to firmly bind the solid particles, it is preferably 0.01 to 10 mass%, more preferably 0.1 to 10 mass%, even more preferably 0.1 to 5 mass%, and particularly preferably 0.2 to 3 mass%.

[0044] The content of each component in the binder-forming polymer is not particularly limited except for the content of the specific components described above, and is appropriately set taking into consideration the physical properties of the entire polymer. The content of the components in the binder-forming polymer is set, for example, so that the total content of all components is 100% by mass. When the binder-forming polymer contains multiple components, the content of each component refers to the total content of the multiple components. The content of the polar functional group-containing component MC is not particularly limited and can be appropriately determined relative to the total content of all components, taking into consideration, for example, the coagulation properties of the polymer binder and the adhesion (binding properties) of the solid particles. When the polar functional group-containing component MC has a carboxy group, the content is determined taking into consideration the content of the component having the carboxy group described above. The content of the polar functional group-containing component MC is, for example, preferably 0 to 20% by mass, more preferably 0.1 to 10% by mass, and even more preferably 1 to 8% by mass.

[0045] The content of other constituent components is not particularly limited, but can be 1 to 100 mass%, preferably 20 to 100 mass%, more preferably 40 to 100 mass%, even more preferably 60 to 100 mass%, and particularly preferably 80 to 100 mass%, relative to the total content of all constituent components.

[0046] The binder-forming polymer is not particularly limited as long as it contains the above-mentioned component MA in the above-mentioned content, and various known polymers can be used. The primary structure of the binder-forming polymer (the bonding mode of the components) is not particularly limited, and can have any bonding mode such as a random structure, a block structure, an alternating structure, or a graft structure.

[0047] Preferred examples of the binder-forming polymer include polymers having at least one bond selected from a urethane bond, a urea bond, an amide bond, an imide bond, an ester bond, and a carbonate bond, or a polymer chain of a carbon-carbon double bond in the main chain, and more preferred are polymers having a polymer chain of a carbon-carbon double bond in the main chain. The bond is not particularly limited as long as it is contained in the main chain of the polymer, and may be contained in a constituent component (repeating unit) and / or as a bond connecting different constituent components. Furthermore, the number of such bonds contained in the main chain is not limited to one type, but may be two or more types, preferably one to six types, and more preferably one to four types. In this case, the bonding pattern of the main chain is not particularly limited, and may include two or more types of bonds randomly, or may be a segmented main chain consisting of segments having specific bonds and segments having other bonds. Among the above bonds, examples of the polymer having a urethane bond, a urea bond, an amide bond, an imide bond, an ester bond or a carbonate bond in the main chain include step-growth polymerization (polycondensation, polyaddition or addition-condensation) polymers such as polyurethane, polyurea, polyamide, polyimide, polyester and polycarbonate bonds, and copolymers thereof.

[0048] In the present invention, the polymer chain of a carbon-carbon double bond refers to a polymer chain formed by polymerization of a carbon-carbon double bond (ethylenically unsaturated group), and specifically refers to a polymer chain formed by polymerization (homopolymerization or copolymerization) of a monomer having a carbon-carbon unsaturated bond. Examples of polymers having a polymer chain of a carbon-carbon double bond in the main chain include chain-polymerized polymers such as fluoropolymers (fluorine-containing polymers), hydrocarbon polymers, vinyl polymers, and (meth)acrylic polymers, with (meth)acrylic polymers being preferred.

[0049] Examples of (meth)acrylic polymers include polymers composed of (co)polymers containing 50% by mass or more of components derived from (meth)acrylic compounds. When each of the above components is derived from a (meth)acrylic compound, the content of these components is also included in the calculation of the content of the components derived from a (meth)acrylic compound. The content of the components derived from a (meth)acrylic compound is more preferably 60% by mass or more, and even more preferably 70% by mass or more. The upper limit of the content can be 100% by mass, but can also be 97% by mass or less. Furthermore, copolymers with a vinyl compound (M2) other than the (meth)acrylic compound (M1) are also preferred as (meth)acrylic polymers. In this case, the content of the components derived from the vinyl compound (M2) is 50% by mass or less, preferably 3 to 40% by mass, and more preferably 3 to 30% by mass.

[0050] Examples of the (meth)acrylic compound (M1) include (meth)acrylic acid compounds, (meth)acrylic acid ester compounds, (meth)acrylamide compounds, and (meth)acrylonitrile compounds, excluding compounds that derive the above-mentioned components MA and MC. Among these, (meth)acrylic acid ester compounds are preferred. Examples of (meth)acrylic acid ester compounds include (meth)acrylic acid alkyl ester compounds and (meth)acrylic acid aryl ester compounds, with (meth)acrylic acid alkyl ester compounds being preferred. The number of carbon atoms in the alkyl group constituting the (meth)acrylic acid alkyl ester compound is not particularly limited, but can be, for example, 1 to 24. From the viewpoint of adhesion and the like, it is preferably 3 to 20, more preferably 4 to 16, and even more preferably 6 to 14. The number of carbon atoms in the aryl group constituting the aryl ester is not particularly limited, but can be, for example, 6 to 24, preferably 6 to 10, and more preferably 6. In the (meth)acrylamide compound, the nitrogen atom of the amide group may be substituted with an alkyl group or an aryl group.

[0051] The vinyl compound (M2) is not particularly limited, but among vinyl compounds copolymerizable with the (meth)acrylic compound (M1), vinyl compounds other than the vinyl compounds that derive the above-mentioned components MA and MC are preferred. Examples include aromatic vinyl compounds such as styrene compounds, vinyl naphthalene compounds, vinyl carbazole compounds, vinyl imidazole compounds, and vinyl pyridine compounds, as well as allyl compounds, vinyl ether compounds, vinyl ester compounds (e.g., vinyl acetate compounds), dialkyl itaconate compounds, and the above-mentioned polymerizable cyclic dicarboxylic acid anhydrides. Examples of vinyl compounds include the "vinyl monomers" described in JP 2015-88486 A. The (meth)acrylic compound (M1) and the vinyl compound (M2) may have a substituent, but one preferred embodiment is that they are unsubstituted. The substituent is not particularly limited, and examples include groups selected from the substituent Z described below, but groups other than the polar functional groups included in the above-mentioned functional group group (a) are preferred.

[0052] Examples of hydrocarbon polymers include polyethylene, polypropylene, natural rubber, polybutadiene, polyisoprene, polystyrene, polystyrene-butadiene copolymers, styrene-based thermoplastic elastomers, polybutylene, acrylonitrile-butadiene copolymers, hydrogenated polymers thereof, and copolymers with copolymerizable compounds such as (meth)acrylic compounds (M1) and vinyl compounds (M2). Examples of styrene-based thermoplastic elastomers or hydrogenated products thereof are not particularly limited, and include styrene-ethylene-butylene-styrene block copolymers (SEBS), styrene-isoprene-styrene block copolymers (SIS), hydrogenated SIS, styrene-butadiene-styrene block copolymers (SBS), hydrogenated SBS, styrene-ethylene-ethylene-propylene-styrene block copolymers (SEEPS), styrene-ethylene-propylene-styrene block copolymers (SEPS), styrene-butadiene rubber (SBR), hydrogenated styrene-butadiene rubber (HSBR), and random copolymers corresponding to the above block copolymers, such as SEBS.

[0053] The binder-forming polymer may have a substituent. The substituent is not particularly limited, but is preferably a group selected from the following substituent Z, and is preferably a group other than the polar functional groups included in the functional group group (a) described above.

[0054] - Substituent Z - An alkyl group (preferably an alkyl group having 1 to 20 carbon atoms, for example, methyl, ethyl, isopropyl, t-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.), an alkenyl group (preferably an alkenyl group having 2 to 20 carbon atoms, for example, vinyl, allyl, oleyl, etc.), an alkynyl group (preferably an alkynyl group having 2 to 20 carbon atoms, for example, ethynyl, butadiynyl, phenylethynyl, etc.), a cycloalkyl group (preferably a cycloalkyl group having 3 to 20 carbon atoms, for example, cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc.), In the present invention, alkyl groups usually include cycloalkyl groups, but will be described separately here.), aryl groups (preferably aryl groups having 6 to 26 carbon atoms, for example, phenyl, 1-naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methylphenyl, etc.), aralkyl groups (preferably aralkyl groups having 7 to 23 carbon atoms, for example, benzyl, phenethyl, etc.), heterocyclic groups (preferably heterocyclic groups having 2 to 20 carbon atoms, more preferably 5- or 6-membered heterocyclic groups having at least one oxygen atom, sulfur atom, or nitrogen atom. Heterocyclic groups include aromatic heterocyclic groups and aliphatic heterocyclic groups.For example, a tetrahydropyran ring group, a tetrahydrofuran ring group, 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-oxazolyl, a pyrrolidone group, etc.), an alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, for example, methoxy, ethoxy, isopropyloxy, benzyloxy, etc.), an aryloxy group (preferably an aryloxy group having 6 to 26 carbon atoms, for example, phenoxy, 1-naphthyloxy, 3-methylphenoxy, 4-methoxyphenoxy, etc.), a heterocyclic oxy group (a group in which an -O- group is bonded to the above heterocyclic group), an alkoxycarbonyl group (preferably or an alkoxycarbonyl group having 2 to 20 carbon atoms, for example, ethoxycarbonyl, 2-ethylhexyloxycarbonyl, dodecyloxycarbonyl, etc.), an aryloxycarbonyl group (preferably an aryloxycarbonyl group having 6 to 26 carbon atoms, for example, phenoxycarbonyl, 1-naphthyloxycarbonyl, 3-methylphenoxycarbonyl, 4-methoxyphenoxycarbonyl, etc.), a heterocyclic oxycarbonyl group (a group in which an —O—CO— group is bonded to the above heterocyclic group), an amino group (preferably an amino group having 0 to 20 carbon atoms, an alkylamino group, or an arylamino group, for example, amino(—NH ２), N,N-dimethylamino, N,N-diethylamino, N-ethylamino, anilino, etc.), sulfamoyl group (preferably a sulfamoyl group having 0 to 20 carbon atoms, for example, N,N-dimethylsulfamoyl, N-phenylsulfamoyl, etc.), acyl group (including an alkylcarbonyl group, an alkenylcarbonyl group, an alkynylcarbonyl group, an arylcarbonyl group, or a heterocyclic carbonyl group, preferably an acyl group having 1 to 20 carbon atoms, for example, acetyl, propionyl, butyryl, octanoyl, hexadecanoyl, acryloyl, methacryloyl, crotonoyl, benzoyl, naphthoyl, nicotinoyl, etc.), acyl Oxy groups (including alkylcarbonyloxy groups, alkenylcarbonyloxy groups, alkynylcarbonyloxy groups, and heterocyclic carbonyloxy groups, preferably acyloxy groups having 1 to 20 carbon atoms, for example, acetyloxy, propionyloxy, butyryloxy, octanoyloxy, hexadecanoyloxy, acryloyloxy, methacryloyloxy, crotonoyloxy, and nicotinoyloxy), aryloyloxy groups (preferably aryloyloxy groups having 7 to 23 carbon atoms, for example, benzoyloxy and naphthoyloxy), carbamoyl groups (preferably carbamoyl groups having 1 to 20 carbon atoms, for example, N,N-dimethylcarbamoyl, N-phenylcarbamoyl, etc.), acylamino groups (preferably acylamino groups having 1 to 20 carbon atoms, for example, acetylamino, benzoylamino, etc.), alkylthio groups (preferably alkylthio groups having 1 to 20 carbon atoms, for example, methylthio, ethylthio, isopropylthio, benzylthio, etc.), arylthio groups (preferably arylthio groups having 6 to 26 carbon atoms, for example, phenylthio, 1-naphthylthio, 3-methylphenylthio, 4-methoxyphenylthio, etc.), heterocyclic thio groups (groups in which an -S- group is bonded to the above heterocyclic group), alkylsulfonyl groups (preferably alkylsulfonyl groups having 1 to 20 carbon atoms, for example, methylsulfonyl, ethylsulfonyl, etc.), arylsulfonyl groups (preferably an arylsulfonyl group having 6 to 22 carbon atoms, for example, benzenesulfonyl; an alkylsilyl group (preferably an alkylsilyl group having 1 to 20 carbon atoms, for example, monomethylsilyl, dimethylsilyl, trimethylsilyl, triethylsilyl; an arylsilyl group (preferably an arylsilyl group having 6 to 42 carbon atoms, for example, triphenylsilyl; an alkoxysilyl group (preferably an alkoxysilyl group having 1 to 20 carbon atoms, for example, monomethoxysilyl, dimethoxysilyl, trimethoxysilyl, triethoxysilyl; an aryloxysilyl group having 6 to 42 carbon atoms, for example, triphenyloxysilyl; an aryloxysilyl group having 6 to 42 carbon atoms, for example, triphenyloxysilyl; a phosphoryl group (preferably a phosphoric acid group having 0 to 20 carbon atoms, for example, -OP(=O)(R, Ｐ ) ２ ), a phosphonyl group (preferably a phosphonyl group having 0 to 20 carbon atoms, for example, —P(═O)(R Ｐ ) ２ ), a phosphinyl group (preferably a phosphinyl group having 0 to 20 carbon atoms, for example, —P(R Ｐ ) ２ ), a phosphonic acid group (preferably a phosphonic acid group having 0 to 20 carbon atoms, for example, —PO(OR Ｐ ) ２ ), sulfo group (sulfonic acid group), carboxy group, hydroxy group, sulfanyl group, cyano group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom, etc.). Ｐis a hydrogen atom or a substituent (preferably a group selected from the substituent Z). Each of the groups listed as the substituent Z may be further substituted with the substituent Z. The alkyl group, alkylene group, alkenyl group, alkenylene group, alkynyl group and / or alkynylene group may be cyclic or chain-like, and may be linear or branched.

[0055] The binder-forming polymer can be synthesized by selecting raw material compounds and polymerizing the raw material compounds using a known method. The method for incorporating each polar functional group is not particularly limited, and examples thereof include a method of copolymerizing a compound having the polar functional group, a method using a polymerization initiator or chain transfer agent having (or generating) the polar functional group, a method utilizing a polymer reaction, an ene reaction to a double bond, an ene-thiol reaction, or an ATRP (atom transfer radical polymerization) polymerization method using a copper catalyst. Alternatively, a polar functional group can be introduced using a functional group present in the main chain, side chain, or terminal of a polymer as a reaction site. For example, a functional group can be introduced by using a compound having a polar functional group and reacting with a dicarboxylic acid anhydride group in a polymer chain.

[0056] Specific examples of binder-forming polymers include the polymers synthesized in the examples, but the present invention is not limited to these.

[0057] -Physical Properties or Characteristics of Binder-Forming Polymer or Polymer Binder-The polymer binder or binder-forming polymer used in the present invention preferably has the following physical properties or characteristics.

[0058] The weight average molecular weight of the binder-forming polymer is 1.0×10 ３ ~1.0 x 10 ７ In terms of the cohesiveness of the polymer binder, it is preferable that the weight average molecular weight of the binder-forming polymer is 1.0 × 10 ４ More than 3.0 × 10 ４ More preferably, 1.0 × 10 ５ More preferably, the upper limit is 1.0 × 10 ７Preferably, the value is 5.0 x 10 or less. ６ More preferably, 1.0 x 10 ６ More preferably, 5.0 x 10 ５ The following are particularly preferred: The weight average molecular weight of the binder-forming polymer can be appropriately adjusted by changing the type and content of the polymerization initiator, the polymerization time, the polymerization temperature, and the like.

[0059] - Measurement of Molecular Weight - In the present invention, unless otherwise specified, the molecular weight of a polymer chain of a polymer or the like refers to a weight average molecular weight or number average molecular weight calculated in terms of standard polystyrene by gel permeation chromatography (GPC). Examples of the measurement method include a method set under the following condition 1 or condition 2 (priority). However, depending on the type of polymer or the like, an appropriate eluent may be selected and used. (Condition 1) Column: Two TOSOH TSKgel Super AWM-H (trade name, manufactured by Tosoh Corporation) connected together Carrier: 10 mM LiBr / N-methylpyrrolidone Measurement temperature: 40°C Carrier flow rate: 1.0 ml / min Sample concentration: 0.1 mass% Detector: RI (refractive index) detector (Condition 2) Column: A column connected together with TOSOH TSKgel Super HZM-H, TOSOH TSKgel Super HZ4000, and TOSOH TSKgel Super HZ2000 (all trade names, manufactured by Tosoh Corporation) is used. Carrier: Tetrahydrofuran Measurement temperature: 40°C Carrier flow rate: 1.0 ml / min Sample concentration: 0.1 mass% Detector: RI (refractive index) detector

[0060] When the binder composition contains a dispersion medium, the polymer binder may be present in a dissolved state in the dispersion medium (binder composition) or may be dispersed in the dispersion medium in the form of particles. In the present invention, "the polymer binder is dissolved in the dispersion medium" means that the polymer binder is dissolved in the dispersion medium in the binder composition, and for example, the solubility of the polymer binder in the solubility measurement described below is 50% or more. The polymer binder is not limited to an embodiment in which the entire polymer binder is dissolved in the dispersion medium in the binder composition, and includes an embodiment in which a portion of the polymer binder is present in an insoluble state. The solubility is measured as follows. That is, approximately 0.1 g of the polymer binder (solid) is precisely weighed, and the precisely weighed mass is designated as W0. Next, the polymer binder and 10 g of a dispersion medium having the same composition as the dispersion medium contained in the binder composition are placed in a container and mixed for 48 hours at a temperature of 25°C and a rotation speed of 100 rpm using a mix rotor (model number VMR-5, manufactured by AS ONE Corporation). Thereafter, the insoluble matter is filtered from the solution, and the obtained solid is vacuum-dried at 120°C for 3 hours, and the mass W1 of the insoluble matter is precisely weighed. Then, the solubility (%) in the dispersion medium is calculated according to the following formula, and the obtained value is regarded as the solubility of the polymer binder in the dispersion medium. Solubility (%) = (W0 - W1) / W0 × 100

[0061] In the present invention, the solubility of the polymer binder in the dispersion medium can be appropriately imparted by the type of polymer forming the polymer binder, the composition of this polymer (type and content of constituent components), the weight-average molecular weight of this polymer, the type or content of the polar functional group described above, and further the combination with the dispersion medium, etc.

[0062] The water concentration of the binder (binder-forming polymer) is preferably 100 ppm (by mass) or less. This binder may be prepared by crystallizing the polymer and drying it, or the binder dispersion may be used as is. The binder-forming polymer is preferably amorphous. In the present invention, a polymer being "amorphous" typically means that no endothermic peak due to crystalline melting is observed when measured at the glass transition temperature.

[0063] The binder-forming polymer may be a non-crosslinked polymer or a crosslinked polymer. Furthermore, when crosslinking of the polymer progresses due to heating or application of voltage, the molecular weight may be larger than the above-mentioned molecular weight. Preferably, the binder-forming polymer has a weight-average molecular weight within the above-mentioned range at the start of use of the all-solid-state secondary battery.

[0064] The binder-forming polymer contained in the polymer binder may be one type or two or more types. The polymer binder may also contain other polymers, etc., as long as the effect of the binder-forming polymer described above is not impaired. As the other polymer, polymers that are commonly used as binders for all-solid-state secondary batteries can be used without any particular limitation.

[0065] The binder composition may contain one or more polymer binders. ＰＢ is not particularly limited, but is preferably 1 to 70% by mass, more preferably 5 to 50% by mass, even more preferably 8 to 40% by mass, and even more preferably 8 to 20% by mass, in terms of binding property and resistance.

[0066] <Dispersion Medium> The binder composition preferably contains a dispersion medium. The dispersion medium may be any organic compound that is liquid in the usage environment, and examples thereof include various organic solvents, specifically alcohol compounds, ether compounds, amide compounds, amine compounds, ketone compounds, aromatic hydrocarbon compounds, aliphatic hydrocarbon compounds, nitrile compounds, and ester compounds. The dispersion medium may be a non-polar dispersion medium (hydrophobic dispersion medium) or a polar dispersion medium (hydrophilic dispersion medium), but a non-polar dispersion medium is preferred because it can exhibit excellent dispersibility. A non-polar dispersion medium generally refers to a medium that has low affinity for water, and in the present invention, examples thereof include ester compounds, ketone compounds, ether compounds, aromatic hydrocarbon compounds, and aliphatic hydrocarbon compounds.

[0067] Examples of alcohol compounds include methyl alcohol, ethyl alcohol, 1-propyl alcohol, 2-propyl alcohol, 2-butanol, ethylene glycol, propylene glycol, glycerin, 1,6-hexanediol, cyclohexanediol, sorbitol, xylitol, 2-methyl-2,4-pentanediol, 1,3-butanediol, and 1,4-butanediol.

[0068] Examples of the ether compound include alkylene glycols (diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, etc.), alkylene glycol monoalkyl ethers (ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene 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.), and cyclic ethers (tetrahydrofuran, dioxane (including 1,2-, 1,3-, and 1,4-isomers), etc.).

[0069] Examples of the amide compound include N,N-dimethylformamide, N-methyl-2-pyrrolidone, 2-pyrrolidinone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, formamide, N-methylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropanamide, and hexamethylphosphoric triamide.

[0070] Examples of amine compounds include triethylamine, diisopropylethylamine, and tributylamine. Examples of ketone compounds include acetone, methyl ethyl ketone, methyl isobutyl ketone (MIBK), cyclopentanone, cyclohexanone, cycloheptanone, dipropyl ketone, dibutyl ketone, diisopropyl ketone, diisobutyl ketone (DIBK), isobutyl propyl ketone, sec-butyl propyl ketone, pentyl propyl ketone, and butyl propyl ketone. Examples of aromatic hydrocarbon compounds include benzene, toluene, xylene, and perfluorotoluene. Examples of aliphatic hydrocarbon compounds include hexane, heptane, octane, nonane, decane, dodecane, cyclohexane, methylcyclohexane, ethylcyclohexane, cycloheptane, cyclooctane, decalin, paraffin, gasoline, naphtha, kerosene, and diesel. Examples of nitrile compounds include acetonitrile, propionitrile, and isobutyronitrile. Examples of the ester compound include ethyl acetate, propyl acetate, butyl acetate, ethyl butyrate, propyl butyrate, isopropyl butyrate, butyl butyrate, isobutyl butyrate, butyl pentanoate, pentyl pentanoate, ethyl isobutyrate, propyl isobutyrate, isopropyl isobutyrate, isobutyl isobutyrate, propyl pivalate, isopropyl pivalate, butyl pivalate, and isobutyl pivalate.

[0071] In the present invention, among these, ether compounds, ketone compounds, aromatic hydrocarbon compounds, aliphatic hydrocarbon compounds, and ester compounds are preferred, and ester compounds, ketone compounds, aromatic hydrocarbon compounds, and ether compounds are more preferred.

[0072] The number of carbon atoms in the compound constituting the dispersion medium is not particularly limited, and is preferably 2 to 30, more preferably 4 to 20, even more preferably 6 to 15, and particularly preferably 7 to 12.

[0073] The boiling point of the dispersion medium at normal pressure (1 atmosphere: 101,325 Pa) is preferably 50° C. or higher, more preferably 70° C. or higher. The upper limit is preferably 250° C. or lower, more preferably 220° C. or lower.

[0074] The binder composition may contain one or more dispersion media. Examples of dispersion media containing two or more dispersion media include xylene (a mixture of xylene isomers in which the molar ratio of the isomers is ortho-isomer:para-isomer:meta-isomer = 1:5:2), mixed xylenes (a mixture of o-xylene, p-xylene, m-xylene, and ethylbenzene), etc. In the present invention, the content of the dispersion medium in the binder composition is not particularly limited and can be set appropriately. For example, the content of the dispersion medium in the binder composition is preferably 10 to 99% by mass, more preferably 30 to 95% by mass, and particularly preferably 40 to 90% by mass.

[0075] <Other Components> In addition to the polymer binder and the metal element-containing component, the binder composition may contain, as other components, various additives, various components appropriately contained in materials for forming constituent layers of secondary batteries, etc. The content of other components in the binder composition is not particularly limited and may be determined appropriately.

[0076] <Preparation of Binder Composition> The binder composition of the present invention can be prepared as a mixture by mixing a polymer binder and a metal element-containing component, preferably a dispersion medium, and other components, for example, using various commonly used mixers. In the present invention, the binder composition is typically prepared by actively mixing the metal element-containing component with the polymer binder. However, if the content of the metal element-containing component in the prepared binder composition is excessive, the content of the metal element-containing component can be adjusted by a conventional method, such as a purification method. The mixing method is not particularly limited, and can be performed using a known mixer such as a ball mill, bead mill, planetary mixer, blade mixer, roll mill, kneader, disk mill, planetary mixer, or narrow gap disperser. The mixing conditions are also not particularly limited. For example, the above components may be mixed all at once or sequentially. The mixing conditions are not particularly limited. The mixing temperature can be 15 to 50°C. The mixing atmosphere may be any of air, dry air (dew point of -20°C or less), and inert gas (for example, argon gas, helium gas, nitrogen gas).

[0077] [Constituent Layer-Forming Material] The constituent layer-forming material of the present invention is a composition containing the binder composition of the present invention (or the above-described constituent components thereof) as a polymer binder component. When the constituent layer-forming material is used as a material for forming a constituent layer of an all-solid-state secondary battery, it is referred to as a solid electrolyte-containing composition for (all-solid-state) secondary batteries. When used as a material for forming an electrode layer of a non-aqueous electrolyte secondary battery, it is also referred to as an electrode composition for a non-aqueous electrolyte secondary battery. The constituent layer-forming material of the present invention contains, in addition to the binder composition of the present invention, appropriate components depending on the application, etc. For example, when it is a non-aqueous electrolyte secondary battery electrode composition, it contains the binder composition of the present invention, an active material, and other components, dispersion medium, etc., as appropriate, as described below. On the other hand, when it is a solid electrolyte-containing composition for a secondary battery, it contains the binder composition of the present invention (or the above-described constituent components thereof), an inorganic solid electrolyte having ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and, as appropriate, an active material, a conductive additive, a dispersion medium, and other components, as described below. In the constituent layer forming material, each component constituting the binder composition of the present invention does not need to be present integrally as a binder composition, and each component may exist independently (separately).Furthermore, in the constituent layer forming material, the polymer binder may be insoluble in the dispersion medium in the composition (including the dispersion medium of the binder composition. Hereinafter, unless otherwise specified, this has the same meaning) and exist in a solid state, or may be dissolved.Dissolving in the dispersion medium is synonymous with dissolving in the dispersion medium described above.

[0078] The constituent layer-forming material of the present invention contains a polymer binder and a predetermined amount of a metal element-containing component, and therefore can form a constituent layer with low resistance, and can produce a sheet for an all-solid-state secondary battery having a constituent layer with low resistance in which solid particles are firmly adhered, and further a low-resistance all-solid-state secondary battery.

[0079] The constituent layer forming material of the present invention is preferably a slurry in which solid particles are dispersed in a dispersion medium. Meanwhile, the polymer binder functions as a binder that firmly binds the solid particles together while maintaining direct contact in the constituent layer formed from the constituent layer forming material. Furthermore, it also functions as a binder that firmly binds the solid particles to a substrate such as a current collector. Note that in the constituent layer forming material, the polymer binder may or may not have the function of binding the solid particles together.

[0080] <Solid Electrolyte-Containing Composition for Secondary Battery> The solid electrolyte-containing composition for a secondary battery of the present invention is preferably a non-aqueous composition. In the present invention, the non-aqueous composition has the same meaning as the binder composition.

[0081] The solid electrolyte-containing composition for a secondary battery of the present invention exhibits the above-mentioned excellent properties, and therefore can be used as a material for forming a sheet for a secondary battery (preferably a sheet for an all-solid-state secondary battery) and an electrode layer of a secondary battery (preferably a constituent layer of an all-solid-state secondary battery).

[0082] The solid electrolyte-containing composition for secondary batteries of the present invention also includes an embodiment containing an active material and the like in addition to an inorganic solid electrolyte (the composition in this embodiment is referred to as an electrode composition). Hereinafter, the components contained in the solid electrolyte-containing composition for secondary batteries of the present invention and the components that can be contained therein will be described.

[0083] (Binder composition) The solid electrolyte-containing composition for secondary batteries of the present invention contains the above-mentioned binder composition. The content of the binder composition in the solid electrolyte-containing composition for secondary batteries can be appropriately determined taking into consideration the content of the polymer binder described below, etc., but is usually set to a ratio that corresponds to the content of the polymer binder described below.

[0084] - Metal Element-Containing Component - The solid electrolyte-containing composition for a secondary battery of the present invention contains one or more metal element-containing components. The metal element-containing component is as described above, including the particle size in the composition. The metal element-containing component contained in the solid electrolyte-containing composition for a secondary battery is usually derived from the binder composition described above. In the present invention, in order to adjust (usually increase) the content of the metal element-containing component in the solid electrolyte-containing composition for a secondary battery, the above-mentioned metal element-containing component used in the binder composition can also be appropriately added and mixed in addition to the binder composition. The metal element-containing component to be added and mixed may be the same or different from the metal element-containing component in the binder composition. The content C of the metal element-containing component in the solid electrolyte-containing composition for a secondary battery ＭＳ is not particularly limited and is appropriately set depending on the content in the binder composition, the amount of the binder composition used, etc. Specifically, the content C of the metal element-containing component ＭＳ is the content C of the metal element-containing component in the binder composition ＭＢ and the amount of the binder composition used in the solid electrolyte-containing composition for secondary batteries. ＭＳ is preferred in that the increase in resistance can be further suppressed while maintaining the battery function, and the solid electrolyte-containing composition for secondary batteries contains 1.0 × 10 －６ ~1.0 x 10 ４ ppm, preferably 1.0 x 10 －３ ~1.0 x 10 ４ ppm, more preferably 1.0 x 10 －３ ~1.0 x 10 ２ ppm, more preferably 1.0 x 10 －２ It is even more preferable that the concentration is 1.0×10 ppm or less, and 1.0×10 －２ It is particularly preferable that the concentration is 1.0 ppm or less, and 1.0 × 10 －２ ~3.0 x 10 －１ It is most preferable that the content C is 1 ppm. ＭＳ is the content C ＭＢ In the solid electrolyte-containing composition for secondary batteries, the content C of the polymer binder can be measured or calculated in the same manner as above.ＰＳ Content C of metal element-containing component relative to ＭＳ The ratio [C ＭＳ / C ＰＳ ] is not particularly limited and can be determined appropriately. For example, the above ratio [C ＭＢ / C ＰＢ ] is preferably the same as

[0085] - Polymer Binder - The solid electrolyte-containing composition for a secondary battery of the present invention contains one or more polymer binders derived from the above-mentioned binder composition. The polymer binder is as described above. In the present invention, in addition to the binder composition, the above-mentioned polymer binder used in the binder composition can also be added and mixed as appropriate. The polymer binder to be added and mixed may be the same or different from the polymer binder in the binder composition. The content C of the polymer binder in the solid electrolyte-containing composition for a secondary battery ＰＳ is not particularly limited, but in terms of ionic conductivity and further binding ability, it is preferably 0.1 to 8.0 mass%, more preferably 0.2 to 4.0 mass%, and even more preferably 0.3 to 2.5 mass%. Furthermore, for the same reasons, the content of the polymer binder in 100 mass% solids of the solid electrolyte-containing composition for secondary batteries is preferably 0.1 to 10.0 mass%, more preferably 0.3 to 5.0 mass%, and even more preferably 0.4 to 3.0 mass%. In the present invention, the mass ratio of the total mass (total amount) of the inorganic solid electrolyte and the active material to the mass of the polymer binder [(mass of inorganic solid electrolyte + mass of active material) / (total mass of polymer binder)] is preferably in the range of 1,000 to 1. This ratio is more preferably 500 to 2, and even more preferably 100 to 10.

[0086] (Inorganic Solid Electrolyte) The solid electrolyte-containing composition for a secondary battery of the present invention contains an inorganic solid electrolyte. In the present invention, the inorganic solid electrolyte refers to an inorganic solid electrolyte, and the solid electrolyte refers to a solid electrolyte capable of moving ions therein. Since it does not contain an organic substance as the main ion-conducting material, it is clearly distinguished from organic solid electrolytes (polymer electrolytes typified by polyethylene oxide (PEO) and the like, and organic electrolyte salts typified by lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and the like). In addition, since inorganic solid electrolytes are solid in a steady state, they are not usually dissociated or liberated into cations and anions. In this respect, inorganic electrolyte salts (LiPF ) that are dissociated or liberated into cations and anions in an electrolytic solution or a polymer are not easily dissociated or liberated into cations and anions. ６ , LiBF ４ , lithium bis(fluorosulfonyl)imide (LiFSI), LiCl, etc.). The inorganic solid electrolyte is not particularly limited as long as it has ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and generally does not have electronic conductivity. The inorganic solid electrolyte can be appropriately selected from solid electrolyte materials commonly used in all-solid-state secondary batteries. Examples of inorganic solid electrolytes include (i) sulfide-based inorganic solid electrolytes, (ii) oxide-based inorganic solid electrolytes, (iii) halide-based inorganic solid electrolytes, and (iv) hydride-based inorganic solid electrolytes. Sulfide-based inorganic solid electrolytes are preferred from the viewpoint of forming a better interface between the active material and the inorganic solid electrolyte. When the all-solid-state secondary battery of the present invention is a lithium-ion battery, the inorganic solid electrolyte preferably has ionic conductivity of lithium ions.

[0087] (i) Sulfide-Based Inorganic Solid Electrolyte The sulfide-based inorganic solid electrolyte preferably contains sulfur atoms, has the ionic conductivity of a metal belonging to Group 1 or 2 of the periodic table, and has electronic insulation. The sulfide-based inorganic solid electrolyte preferably contains at least Li, S, and P as elements and has lithium ion conductivity, but may contain elements other than Li, S, and P as appropriate.

[0088] Examples of sulfide-based inorganic solid electrolytes include lithium ion conductive inorganic solid electrolytes having a composition represented by the following formula (S1): ａ１ M ｂ１ P ｃ１ S ｄ１ A ｅ１ (S1) In formula (S1), L represents an element selected from Li, Na, and K, and Li is preferred. M represents an element selected from B, Zn, Sn, Si, Cu, Ga, Sb, Al, and Ge. A represents an element selected from I, Br, Cl, and F. a1 to e1 represent the composition ratio of each element, and a1:b1:c1:d1:e1 satisfies the ratio of 1-12:0-5:1:2-12:0-10. a1 is preferably 1-9, and more preferably 1.5-7.5. b1 is preferably 0-3, and more preferably 0-1. d1 is preferably 2.5-10, and more preferably 3.0-8.5. e1 is preferably 0-5, and more preferably 0-3.

[0089] The composition ratio of each element can be controlled by adjusting the blending amounts of raw material compounds when producing the sulfide-based inorganic solid electrolyte, as described below.

[0090] The sulfide-based inorganic solid electrolyte may be amorphous (glass) or crystallized (glass-ceramic), or may be only partially crystallized. For example, Li-P-S-based glass containing Li, P, and S, or Li-P-S-based glass-ceramic containing Li, P, and S can be used. The sulfide-based inorganic solid electrolyte may be, for example, lithium sulfide (Li ２ S), phosphorus sulfide (e.g., diphosphorus pentasulfide (P ２ S ５ )), elemental phosphorus, elemental sulfur, sodium sulfide, hydrogen sulfide, lithium halides (e.g., LiI, LiBr, LiCl), and sulfides of the elements represented by M (e.g., SiS ２ , SnS, GeS ２ ) can be produced by reacting at least two or more raw materials.

[0091] Li in Li-P-S glass and Li-P-S glass ceramics ２ S and P ２ S ５The ratio of Li ２ S:P ２ S ５ The molar ratio of Li is preferably 60:40 to 90:10, more preferably 68:32 to 78:22. ２ S and P ２ S ５ By setting the ratio to this range, the lithium ion conductivity can be made high. Specifically, the lithium ion conductivity is preferably set to 1×10 －４ S / cm or more, more preferably 1×10 －３ There is no particular upper limit, but it can be 1 × 10 －１ It is practical to have a viscosity of 200 S / cm or less.

[0092] As a specific example of a sulfide-based inorganic solid electrolyte, a combination of raw materials is shown below. For example, Li ２ S-P ２ S ５ , Li ２ S-P ２ S ５ -LiCl, Li ２ S-P ２ S ５ -H ２ S., Li. ２ S-P ２ S ５ -H ２ S-LiCl, Li ２ S-LiI-P ２ S ５ , Li ２ S-LiI-Li ２ O-P ２ S ５ , Li ２ S-LiBr-P ２ S ５ , Li ２ S-Li ２ O-P ２ S ５ , Li ２ S-Li ３ P.O. ４ -P ２ S ５ , Li ２ S-P ２ S ５ -P ２ O ５ , Li２ S-P ２ S ５ -SiS ２ 、Li ２ S-P ２ S ５ -SiS ２ -LiCl、Li ２ S-P ２ S ５ -SnS、Li ２ S-P ２ S ５ -Al ２ S ３ 、Li ２ S-GeS ２ 、Li ２ S-GeS ２ -ZnS、Li ２ S-Ga ２ S ３ 、Li ２ S-GeS ２ -Ga ２ S ３ 、Li ２ S-GeS ２ -P ２ S ５ 、Li ２ S-GeS ２ -Sb ２ S ５ 、Li ２ S-GeS ２ -Al ２ S ３ 、Li ２ S-SiS ２ 、Li ２ S-Al ２ S ３ 、Li ２ S-SiS ２ -Al ２ S ３ 、Li ２ S-SiS ２ -P ２ S ５ 、Li ２ S-SiS ２ -P ２ S ５ -LiI、Li ２ S-SiS ２ -LiI、Li ２ S-SiS ２ -Li ４ SiO４ , Li ２ S-SiS ２ -Li ３ P.O. ４ , Li １０ GeP ２ S １２ However, the mixing ratio of each raw material is not important. As a method for synthesizing a sulfide-based inorganic solid electrolyte material using such a raw material composition, for example, an amorphization method can be mentioned. Examples of the amorphization method include a mechanical milling method, a solution method, and a melt quenching method. This is because processing at room temperature becomes possible, and the manufacturing process can be simplified.

[0093] (ii) Oxide-based inorganic solid electrolyte The oxide-based inorganic solid electrolyte preferably contains oxygen atoms, has the ionic conductivity of a metal belonging to Group 1 or 2 of the periodic table, and has electronic insulation. The oxide-based inorganic solid electrolyte preferably has an ionic conductivity of 1×10 －６ S / cm or more, and 5×10 －６ S / cm or more is more preferable, and 1×10 －５ The upper limit is not particularly limited, but it is preferably 1 × 10 －１ It is practical to have a viscosity of 200 S / cm or less.

[0094] Specific examples of the compound include Li ｘａ La ｙａ TiO ３ [xa satisfies 0.3≦xa≦0.7, and ya satisfies 0.3≦ya≦0.7.] (LLT); Li ｘｂ La ｙｂ Zr ｚｂ M ｂｂ ｍｂ O ｎｂ (M ｂｂ is one or more elements selected from Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In, and Sn. xb satisfies 5≦xb≦10, yb satisfies 1≦yb≦4, zb satisfies 1≦zb≦4, mb satisfies 0≦mb≦2, and nb satisfies 5≦nb≦20; Li ｘｃ B ｙｃ M ｃｃ ｚｃO ｎｃ (M ｃｃ is one or more elements selected from C, S, Al, Si, Ga, Ge, In, and Sn. xc satisfies 0<xc≦5, yc satisfies 0<yc≦1, zc satisfies 0<zc≦1, and nc satisfies 0<nc≦6; Li ｘｄ (Al, Ga) ｙｄ (Ti, Ge) ｚｄ Si ａｄ P ｍｄ O ｎｄ (xd satisfies 1≦xd≦3, yd satisfies 0≦yd≦1, zd satisfies 0≦zd≦2, ad satisfies 0≦ad≦1, md satisfies 1≦md≦7, and nd satisfies 3≦nd≦13); Li （３－２ｘｅ） M ｅｅ ｘｅ D ｅｅ O(xe represents a number between 0 and 0.1, and M ｅｅ represents a divalent metal atom. ｅｅ represents a halogen atom or a combination of two or more halogen atoms; Li ｘｆ Si ｙｆ O ｚｆ (xf satisfies 1≦xf≦5, yf satisfies 0<yf≦3, 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); Li ３ BO ３ Li ３ BO ３ -Li ２ SO ４ Li ２ Alumni ２ O ３ -P ２ O ５ Li ２ O—SiO ２ Li ６ BaLa ２ Ta ２ O １２ Li ３ P.O. （４－３／２ｗ） N ｗ(w is w<1); Li having a LISICON (Lithium super ionic conductor) type crystal structure ３．５ Zn ０．２５ GeO ４ La having a perovskite crystal structure ０．５５ Li ０．３５ TiO ３ LiTi having a NASICON (sodium super ionic conductor) type crystal structure ２ P ３ O １２ Li １＋ｘｈ＋ｙｈ (Al, Ga) ｘｈ (Ti, Ge) ２－ｘｈ Si ｙｈ P ３－ｙｈ O １２ (xh satisfies 0≦xh≦1, and yh satisfies 0≦yh≦1); Li having a garnet-type crystal structure ７ La ３ Zr ２ O １２ (LLZ), etc. Phosphorus compounds containing Li, P, and O are also desirable. For example, lithium phosphate (Li ３ P.O. ４ ) LiPON, in which part of the oxygen element of lithium phosphate is replaced with nitrogen element; LiPOD １ (D １ is preferably one or more elements selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Ag, Ta, W, Pt, and Au. １ ON (A １ is one or more elements selected from Si, B, Ge, Al, C and Ga.) can also be preferably used.

[0095] (iii) Halide-based inorganic solid electrolyte The halide-based inorganic solid electrolyte is preferably a compound containing a halogen atom, having ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and having electronic insulation. The halide-based inorganic solid electrolyte is not particularly limited, but examples thereof include LiCl, LiBr, LiI, and Li described in ADVANCED MATERIALS, 2018, 30, 1803075. ３ YBr ６ , Li ３ YCl ６ Among them, Li ３ YBr ６ , Li ３ YCl ６ is preferred.

[0096] (iv) Hydride-Based Inorganic Solid Electrolyte The hydride-based inorganic solid electrolyte is preferably a compound that contains hydrogen atoms, has the ionic conductivity of a metal belonging to Group 1 or 2 of the periodic table, and has electronic insulation. The hydride-based inorganic solid electrolyte is not particularly limited, but examples thereof include LiBH ４ , Li ４ (BH ４ ) ３ I, 3LiBH ４ -LiCl, etc.

[0097] The inorganic solid electrolyte is preferably in a particulate form in the solid electrolyte-containing composition for secondary batteries. In this case, the particle diameter (volume average particle diameter) of the inorganic solid electrolyte is not particularly limited, but is preferably 0.01 μm or more, more preferably 0.1 μm or more. The upper limit is preferably 100 μm or less, more preferably 50 μm or less. The particle diameter of the inorganic solid electrolyte is measured by the following procedure. Particles of the inorganic solid electrolyte are diluted with water (heptane in the case of substances unstable in water) in a 20 mL sample bottle to prepare a 1 mass % dispersion. The diluted dispersion sample is irradiated with 1 kHz ultrasound for 10 minutes and used for testing immediately thereafter. Using this dispersion sample, data is acquired 50 times using a quartz measurement cell at a temperature of 25°C using a laser diffraction / scattering particle size distribution analyzer LA-920 (trade name, manufactured by HORIBA Corporation), to obtain the volume average particle diameter. For other detailed conditions, etc., refer to the description in Japanese Industrial Standards (JIS) Z 8828:2013 "Particle size analysis - dynamic light scattering method." Five samples are prepared for each level, and the average value is used.

[0098] The method for adjusting the particle size is not particularly limited, and known methods can be applied, such as a method using a conventional pulverizer or classifier. Suitable pulverizers or classifiers include, for example, a mortar, a ball mill, a sand mill, a vibration ball mill, a satellite ball mill, a planetary ball mill, a swirling airflow jet mill, or a sieve. Wet pulverization can be performed in the presence of a dispersion medium such as water or methanol. Classification is preferably performed to obtain the desired particle size. Classification is not particularly limited, and can be performed using a sieve, an air classifier, or the like. Both dry and wet classification methods can be used.

[0099] The solid electrolyte-containing composition for secondary batteries may contain one or more inorganic solid electrolytes. The content of the inorganic solid electrolyte in the solid electrolyte-containing composition for secondary batteries is not particularly limited. However, from the viewpoint of binding property and dispersion characteristics, it is preferably 50% by mass or more, more preferably 70% by mass or more, and particularly preferably 90% by mass or more, based on 100% by mass of the solid content. From the same viewpoint, the upper limit is preferably 99.9% by mass or less, more preferably 99.5% by mass or less, and particularly preferably 99% by mass or less. However, when the solid electrolyte-containing composition for secondary batteries contains an active material described below, the content of the inorganic solid electrolyte in the solid electrolyte-containing composition for secondary batteries is preferably such that the total content of the active material and the inorganic solid electrolyte is within the above range. In the present invention, the solid content (solid component) refers to components that do not volatilize or evaporate when the solid electrolyte-containing composition for secondary batteries is dried at 150°C under a nitrogen atmosphere at an atmospheric pressure of 1 mmHg for 6 hours. Typically, it refers to components other than the dispersion medium described below.

[0100] (Active Material) The solid electrolyte-containing composition for a secondary battery of the present invention preferably contains an active material capable of inserting and releasing ions of a metal belonging to Group 1 or Group 2 of the periodic table. Examples of the active material include a positive electrode active material and a negative electrode active material, as described below. In the present invention, a solid electrolyte-containing composition for a secondary battery containing an active material (positive electrode active material or negative electrode active material) may be referred to as an electrode composition (positive electrode composition or negative electrode composition).

[0101] - Positive Electrode Active Material - The positive electrode active material is an active material capable of inserting and releasing ions of a metal belonging to Group 1 or Group 2 of the periodic table, and is preferably one that can insert and release lithium ions reversibly. The material is not particularly limited as long as it has the above-mentioned properties, and may be a transition metal oxide or an element that can be composited with Li, such as sulfur. Among these, it is preferable to use a transition metal oxide as the positive electrode active material, and the transition metal element M ａ A transition metal oxide containing one or more elements selected from Co, Ni, Fe, Mn, Cu, and V is more preferred. ｂ(Elements of Group 1 (Ia) of the periodic table other than lithium, elements of Group 2 (IIa), Al, Ga, In, Ge, Sn, Pb, Sb, Bi, Si, P, B, etc.) may be mixed. ａ The amount of Li / M is preferably 0 to 30 mol % relative to the amount of Li / M (100 mol %). ａ More preferably, the transition metal oxides are synthesized by mixing them so that the molar ratio of the above is 0.3 to 2.2. Specific examples of the transition metal oxide include (MA) a transition metal oxide having a layered rock salt structure, (MB) a transition metal oxide having a spinel structure, (MC) a lithium-containing transition metal phosphate compound, (MD) a lithium-containing transition metal halide phosphate compound, and (ME) a ​​lithium-containing transition metal silicate compound.

[0102] (MA) Specific examples of transition metal oxides having a layered rock salt structure include LiCoO ２ (Lithium cobalt oxide [LCO]), LiNi ２ O ２ (lithium nickel oxide), LiNi ０．８５ Co ０．１０ Al ０．０５ O ２ (nickel cobalt lithium aluminum oxide [NCA]), LiNi １／３ Co １／３ Mn １／３ O ２ (Lithium nickel manganese cobalt oxide [NMC]) and LiNi ０．５ Mn ０．５ O ２ (Lithium manganese nickel oxide). (MB) Specific examples of transition metal oxides having a spinel structure include LiMn ２ O ４ (LMO), LiCoMnO ４ , Li ２ FeMn ３ O ８ , Li ２ CuMn ３ O ８ , Li ２ CrMn ３ O ８ and Li ２ NiMn ３ O ８Examples of the (MC) lithium-containing transition metal phosphate compound include LiFePO ４ and Li ３ Fe ２ (P.O. ４ ) ３ Olivine-type iron phosphate salts such as LiFeP ２ O ７ Iron pyrophosphates such as LiCoPO ４ Cobalt phosphates such as Li ３ V ２ (P.O. ４ ) ３ (MD) Examples of lithium-containing transition metal halide phosphate compounds include, for example, Li ２ FePO ４ Fluorophosphate iron salts such as F, Li ２ MnPO ４ Fluorophosphate manganese salts such as F and Li ２ CoPO ４ Examples of the (ME) lithium-containing transition metal silicate compound include cobalt fluoride phosphates such as Li ２ FeSiO ４ , Li ２ MnSiO ４ , Li ２ CoSiO ４ In the present invention, transition metal oxides having a layered rock salt structure (MA) are preferred, and LCO or NMC are more preferred.

[0103] The shape of the positive electrode active material is not particularly limited, but it is preferably particulate in the solid electrolyte-containing composition for secondary batteries. When the positive electrode active material is particulate, the particle size (volume average particle size) of the positive electrode active material is not particularly limited. For example, it can be 0.1 to 50 μm. The particle size of the positive electrode active material particles can be measured in the same manner as the particle size of the inorganic solid electrolyte. The positive electrode active material obtained by the firing method may be used after washing with water, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent.

[0104] The solid electrolyte-containing composition for a secondary battery of the present invention may contain one or more positive electrode active materials. The content of the positive electrode active materials in the solid electrolyte-containing composition for a secondary battery is not particularly limited, and is preferably 10 to 97 mass %, more preferably 30 to 95 mass %, even more preferably 40 to 93 mass %, and particularly preferably 50 to 90 mass %, based on 100 mass % of the solid content.

[0105] - Negative Electrode Active Material - The negative electrode active material is an active material capable of inserting and releasing ions of a metal belonging to Group 1 or 2 of the periodic table, and is preferably one capable of reversibly inserting and releasing lithium ions. The material is not particularly limited as long as it has the above-mentioned properties, and examples thereof include carbonaceous materials, metal oxides, metal composite oxides, lithium alone, lithium alloys, and negative electrode active materials capable of forming an alloy (alloyable) with lithium. Among these, carbonaceous materials, metal composite oxides, and lithium alone are preferred from the viewpoint of reliability. Active materials capable of alloying with lithium are preferred in terms of enabling the production of an all-solid-state secondary battery with a large capacity.

[0106] The carbonaceous material used as the negative electrode active material is a material essentially composed of carbon. Examples include carbon black such as petroleum pitch and acetylene black (AB), graphite (natural graphite, artificial graphite such as vapor-grown graphite, etc.), and carbonaceous materials obtained by calcining various synthetic resins such as PAN (polyacrylonitrile)-based resins or furfuryl alcohol resins. Further examples include various carbon fibers 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, as well as mesophase microspheres, graphite whiskers, and flat graphite. These carbonaceous materials can also be divided into difficult-to-graphitize carbonaceous materials (also called hard carbon) and graphite-based carbonaceous materials depending on the degree of graphitization. Furthermore, the carbonaceous material preferably has the interplanar spacing or density and crystallite size described in JP-A-62-22066, JP-A-2-6856, and JP-A-3-45473. The carbonaceous material does not need to be a single material, and a mixture of natural graphite and artificial graphite described in JP-A-5-90844, graphite having a coating layer described in JP-A-6-4516, etc. can also be used. As the carbonaceous material, hard carbon or graphite is preferably used, and graphite is more preferably used.

[0107] The oxide of a metal or metalloid element used as the negative electrode active material is not particularly limited as long as it is an oxide capable of absorbing and releasing lithium, and examples thereof include oxides of metal elements (metal oxides), composite oxides of metal elements, or composite oxides of metal elements and metalloid elements (collectively referred to as metal composite oxides), and oxides of metalloid elements (metalloid oxides). Among these oxides, amorphous oxides are preferred, and chalcogenides, which are reaction products of metal elements and elements of Group 16 of the periodic table, are also preferred. In the present invention, the term "metalloid element" refers to an element that exhibits properties intermediate between metal elements and non-metalloid elements, and typically includes six elements: boron, silicon, germanium, arsenic, antimony, and tellurium, and three elements: selenium, polonium, and astatine. Furthermore, "amorphous" refers to an element that has a broad scattering band with a peak in the 2θ range of 20° to 40° in an X-ray diffraction method using CuKα radiation, and may also have crystalline diffraction lines. The strongest intensity of the crystalline diffraction lines observed at 2θ values ​​of 40° to 70° is preferably 100 times or less, more preferably 5 times or less, the diffraction line intensity at the apex of a broad scattering band observed at 2θ values ​​of 20° to 40°, and it is particularly preferable that the crystal has no crystalline diffraction lines.

[0108] Among the compound group consisting of the amorphous oxides and chalcogenides, amorphous oxides or chalcogenides of metalloid elements are more preferred, and (composite) oxides or chalcogenides consisting of one element selected from Groups 13 (IIIB) to 15 (VB) of the periodic table (e.g., Al, Ga, Si, Sn, Ge, Pb, Sb, and Bi) alone or in combination of two or more elements thereof are particularly preferred. Specific examples of preferred amorphous oxides and chalcogenides include, for example, Ga ２ O ３ , GeO, PbO, PbO ２ , Pb ２ O ３ , Pb ２ O ４ , Pb ３ O ４ , Sb ２ O ３ , Sb ２ O ４ , Sb ２ O ８Bi ２ O ３ , Sb ２ O ８ Si ２ O ３ , Sb ２ O ５ , Bi ２ O ３ , Bi ２ O ４ , GeS, PbS, PbS ２ , Sb ２ S ３ or Sb ２ S ５ Suitable examples of negative electrode active materials that can be used in combination with amorphous oxides mainly containing Sn, Si, or Ge include carbonaceous materials that can occlude and / or release lithium ions or lithium metal, lithium alone, lithium alloys, and negative electrode active materials that can be alloyed with lithium.

[0109] The oxides of metal or semi-metal elements, particularly the metal (composite) oxides and the chalcogenides, preferably contain at least one of titanium and lithium as a constituent component from the viewpoint of high current density charge / discharge characteristics. Examples of the lithium-containing metal composite oxide (lithium composite metal oxide) include composite oxides of lithium oxide and the metal (composite) oxides or the chalcogenides, more specifically, Li ２ SnO ２ The negative electrode active material, for example, a metal oxide, preferably contains titanium element (titanium oxide). Specifically, Li ４ Ti ５ O １２ Lithium titanate (LTO) is preferred because it has small volume fluctuations during absorption and desorption of lithium ions, has excellent rapid charge and discharge characteristics, suppresses electrode deterioration, and can improve the life of the lithium ion secondary battery.

[0110] The lithium alloy used as the negative electrode active material is not particularly limited as long as it is an alloy that is commonly used as a negative electrode active material for secondary batteries, and examples thereof include lithium-aluminum alloys, specifically lithium-aluminum alloys having lithium as the base metal and 10 mass % of aluminum added thereto.

[0111] The negative electrode active material capable of forming an alloy with lithium is not particularly limited as long as it is one commonly used as a negative electrode active material for secondary batteries. Examples of such active materials include (negative electrode) active materials (alloys, etc.) containing silicon or tin, and metals such as Al and In. A negative electrode active material containing silicon (silicon-containing active material) that enables higher battery capacity is preferred, and a silicon-containing active material having a silicon content of 50 mol% or more of the total constituent elements is more preferred. Generally, negative electrodes containing these negative electrode active materials (e.g., Si negative electrodes containing silicon-containing active materials, Sn negative electrodes containing tin-containing active materials, etc.) can absorb more Li ions than carbon negative electrodes (e.g., graphite and acetylene black). That is, the amount of Li ions absorbed per unit mass increases. Therefore, the battery capacity (energy density) can be increased. As a result, there is an advantage in that the battery operating time can be extended. Examples of silicon-containing active materials include silicon materials such as Si and SiOx (0<x≦1), and silicon-containing alloys containing titanium, vanadium, chromium, manganese, nickel, copper, lanthanum, etc. (e.g., LaSi ２ , VSi ２ , La—Si, Gd—Si, Ni—Si), or textured active materials (e.g., LaSi ２ / Si), and also SnSiO ３ , SnSiS ３ Examples of the tin-containing negative electrode active material include Sn, SnO, and SnO. SiOx itself can be used as a negative electrode active material (semi-metal oxide), and can also be used as a negative electrode active material (precursor material) that can be alloyed with lithium because it generates Si during operation of the all-solid-state secondary battery. Examples of the tin-containing negative electrode active material include Sn, SnO, and SnO. ２ , SnS, SnS ２ and active materials containing the above silicon and tin elements. Also, composite oxides with lithium oxide, for example, Li ２ SnO ２ It is also possible to cite the following.

[0112] In the present invention, the above-mentioned negative electrode active material can be used without any particular limitation. However, in terms of battery capacity, a negative electrode active material that can be alloyed with lithium is a preferred embodiment. Among these, the above-mentioned silicon material or silicon-containing alloy (alloy containing silicon element) is more preferred, and it is even more preferred that the negative electrode active material contains silicon (Si) or a silicon-containing alloy.

[0113] The chemical formula of the compound obtained by the above calcination method can be measured by inductively coupled plasma (ICP) emission spectroscopy, or simply calculated from the difference in mass of the powder before and after calcination.

[0114] The shape of the negative electrode active material is not particularly limited, but is preferably particulate in the solid electrolyte-containing composition for secondary batteries. When the negative electrode active material is particulate, the particle diameter of the negative electrode active material is not particularly limited, but is preferably 0.1 to 60 μm. The particle diameter of the negative electrode active material particles can be measured in the same manner as the particle diameter of the inorganic solid electrolyte.

[0115] The solid electrolyte-containing composition for a secondary battery of the present invention may contain one or more negative electrode active materials. The content of the negative electrode active materials in the solid electrolyte-containing composition for a secondary battery is not particularly limited, and is preferably 10 to 90 mass %, more preferably 20 to 85 mass %, even more preferably 30 to 80 mass %, and still more preferably 40 to 75 mass %, based on 100 mass % of the solid content.

[0116] In the present invention, when the negative electrode active material layer is formed by charging the secondary battery, ions of a metal belonging to Group 1 or 2 of the periodic table that are generated in the all-solid-state secondary battery can be used instead of the above-mentioned negative electrode active material. The negative electrode active material layer can be formed by bonding these ions with electrons and depositing them as a metal.

[0117] - Active Material Coating - The surfaces of the positive electrode active material and the negative electrode active material may be coated with another metal oxide. Examples of the surface coating agent include metal oxides containing Ti, Nb, Ta, W, Zr, Al, Si, or Li. Specific examples include titanate spinel, tantalum-based oxides, niobium-based oxides, and lithium niobate-based compounds. Specific examples include Li ４ Ti５ O １２ , Li ２ Ti ２ O ５ , LiTaO ３ , LiNbO ３ , LiAlO ２ , Li ２ ZrO ３ , Li ２ WO ４ , Li ２ TiO ３ , Li ２ B ４ O ７ , Li ３ P.O. ４ , Li ２ MoO ４ , Li ３ BO ３ , LiBO ２ , Li ２ CO ３ , Li ２ SiO ３ , SiO ２ , TiO ２ , ZrO ２ , Al ２ O ３ , B ２ O ３ The surface of the electrode containing the positive electrode active material or the negative electrode active material may be surface-treated with sulfur or phosphorus. Furthermore, the particle surfaces of the positive electrode active material or the negative electrode active material may be surface-treated with actinic rays or an active gas (plasma, etc.) before or after the surface coating.

[0118] (Conductive Aid) The solid electrolyte-containing composition for a secondary battery of the present invention may contain a conductive aid. There are no particular limitations on the conductive aid, and any commonly known conductive aid can be used. For example, the conductive aid may be an electron conductive material such as graphites such as natural graphite and artificial graphite, carbon blacks such as acetylene black, ketjen black, and furnace black, amorphous carbon such as needle coke, carbon fibers such as vapor-grown carbon fibers or carbon nanotubes, or carbonaceous materials such as graphene or fullerene. Alternatively, metal powders or metal fibers such as copper and nickel may be used, or conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene, and polyphenylene derivatives may be used. In the present invention, when an active material and a conductive aid are used in combination, the conductive aid is one of the above conductive aids that does not undergo insertion and release of ions (preferably Li ions) of a metal belonging to Group 1 or Group 2 of the periodic table when the battery is charged and discharged, and does not function as an active material. Therefore, among the conductive additives, those that can function as an active material in the active material layer when the battery is charged and discharged are classified as active materials rather than as conductive additives. Whether or not a conductive additive functions as an active material when the battery is charged and discharged is not uniquely determined, but is determined by the combination with the active material.

[0119] The conductive assistant is preferably in particulate form in the solid electrolyte-containing composition for secondary batteries. When the conductive assistant is particulate, the particle size (volume average particle size) of the conductive assistant is not particularly limited, but is preferably 0.02 to 1.0 μm, and more preferably 0.03 to 0.5 μm. The particle size of the conductive assistant can be measured in the same manner as the particle size of the inorganic solid electrolyte. The conductive assistant contained in the solid electrolyte-containing composition for secondary batteries of the present invention may be one type or two or more types. When the solid electrolyte-containing composition for secondary batteries of the present invention contains a conductive assistant, the content of the conductive assistant in the solid electrolyte-containing composition for secondary batteries is preferably 0 to 10 mass %, and more preferably 1 to 5 mass %, based on 100 mass % of the solid content.

[0120] (Dispersion Medium) The solid electrolyte-containing composition for secondary batteries of the present invention may contain a dispersion medium. Examples of the dispersion medium contained in the solid electrolyte-containing composition for secondary batteries include a dispersion medium derived from the binder composition and a dispersion medium used in preparing the solid electrolyte-containing composition for secondary batteries. Such a dispersion medium may be an organic compound that disperses or dissolves the above-mentioned components and is liquid in the usage environment. For example, the organic solvents described above for the binder composition may be mentioned, and the preferred examples are the same. The dispersion medium used in preparing the solid electrolyte-containing composition for secondary batteries may be the same or different from the dispersion medium in the binder composition. The solid electrolyte-containing composition for secondary batteries may contain one or more types of dispersion medium. The content of the dispersion medium in the solid electrolyte-containing composition for secondary batteries is not particularly limited and can be set appropriately. For example, the content of the dispersion medium in the solid electrolyte-containing composition for secondary batteries is preferably 20 to 80% by mass, more preferably 30 to 70% by mass, and particularly preferably 40 to 60% by mass.

[0121] (Lithium Salt) The solid electrolyte-containing composition for a secondary battery of the present invention also preferably contains a lithium salt (supporting electrolyte). The lithium salt is preferably a lithium salt typically used in this type of product, and is not particularly limited. For example, the lithium salts described in paragraphs 0082 to 0085 of JP 2015-088486 A are preferred. When the solid electrolyte-containing composition for a secondary battery of the present invention contains a lithium salt, the content of the lithium salt is preferably 0.1 parts by mass or more, more preferably 5 parts by mass or more, per 100 parts by mass of the solid electrolyte. The upper limit is preferably 50 parts by mass or less, more preferably 20 parts by mass or less.

[0122] (Dispersant) The solid electrolyte-containing composition for secondary batteries of the present invention does not need to contain any dispersant other than the polymer binder because the above-mentioned polymer binder also functions as a dispersant, but it may contain a dispersant. As the dispersant, one that is normally used in all-solid-state secondary batteries can be appropriately selected and used. Generally, a compound intended for particle adsorption and steric repulsion and / or electrostatic repulsion is preferably used.

[0123] (Other Additives) The solid electrolyte-containing composition for secondary batteries of the present invention may contain, as appropriate, other components in addition to the above components, ionic liquids, thickeners, crosslinking agents (those that undergo a crosslinking reaction by radical polymerization, condensation polymerization, or ring-opening polymerization, etc.), polymerization initiators (those that generate acids or radicals by heat or light, etc.), antifoaming agents, leveling agents, dehydrating agents, antioxidants, etc. The ionic liquid is contained to further improve ionic conductivity, and known ionic liquids can be used without particular limitation. In addition, polymers other than the above-mentioned binder-forming polymers, commonly used binders, etc. may be contained.

[0124] <Preparation of Constituent Layer-Forming Material> The constituent layer-forming material of the present invention can be prepared as a mixture, preferably as a slurry, by mixing the above-mentioned binder composition with the above-mentioned components according to the intended use, for example, using the above-mentioned mixer. Alternatively, the constituent layer-forming material can be prepared without preparing the above-mentioned binder composition. For example, the constituent layer-forming material can be prepared by mixing the above-mentioned polymer binder, the above-mentioned metal element-containing component, and the above-mentioned components according to the intended use in a ratio that results in a predetermined content in the constituent layer-forming material. The mixing conditions are not particularly limited, and examples thereof include the mixing conditions used in preparing the above-mentioned binder composition. Since inorganic solid electrolytes are prone to react with moisture, it is preferable to perform the mixing in dry air or in an inert gas.

[0125] [Sheet for Nonaqueous Secondary Battery] A sheet for a nonaqueous secondary battery can be produced using the constituent layer-forming material of the present invention. This sheet for a nonaqueous secondary battery is a sheet-like molded article capable of forming an electrode layer of a nonaqueous secondary battery, and includes various embodiments depending on its application. Below, a sheet for an all-solid-state secondary battery, which is a preferred embodiment of the sheet for a nonaqueous secondary battery, will be described, but the following content regarding this sheet for an all-solid-state secondary battery can also be applied to the sheet for a nonaqueous secondary battery.

[0126] <Sheet for All-Solid-State Secondary Battery> The sheet for an all-solid-state secondary battery of the present invention is a sheet-like molded article capable of forming a constituent layer of an all-solid-state secondary battery, and includes various embodiments depending on its application. Examples include a sheet preferably used for a solid electrolyte layer (also referred to as a solid electrolyte sheet for an all-solid-state secondary battery), a sheet preferably used for an electrode, or a laminate of an electrode and a solid electrolyte layer (electrode sheet for an all-solid-state secondary battery), and the like. In the present invention, these various sheets are collectively referred to as a sheet for an all-solid-state secondary battery. In the present invention, each layer constituting the sheet for an all-solid-state secondary battery may have a single-layer structure or a multi-layer structure.

[0127] In the sheet for an all-solid-state secondary battery, the solid electrolyte layer or active material layer is formed from the solid electrolyte-containing composition for a secondary battery of the present invention. The constituent layer formed from the solid electrolyte-containing composition for a secondary battery of the present invention is formed from components derived from the solid electrolyte-containing composition for a secondary battery, and typically, solid particles (inorganic solid electrolyte, conductive additive, and active material) and a polymer binder are firmly adhered (bound) together in a mixed state. Furthermore, it is preferable that the polymer binder interacts with the metal element-containing component and aggregates. This sheet for an all-solid-state secondary battery can be incorporated into an all-solid-state secondary battery by peeling off the substrate as appropriate, or by incorporating it directly into the all-solid-state secondary battery, thereby achieving low resistance in the all-solid-state secondary battery.

[0128] The solid electrolyte sheet for an all-solid-state secondary battery of the present invention may be any sheet having a solid electrolyte layer, and may be a sheet in which the solid electrolyte layer is formed on a substrate, or a sheet formed from the solid electrolyte layer without a substrate (a sheet from which the substrate has been peeled off). The solid electrolyte sheet for an all-solid-state secondary battery may have other layers in addition to the solid electrolyte layer. Examples of other layers include a protective layer (release sheet), a current collector, and a coating layer. The solid electrolyte layer of the solid electrolyte sheet for an all-solid-state secondary battery is preferably formed from the solid electrolyte-containing composition for a secondary battery of the present invention. The content of each component in this solid electrolyte layer is not particularly limited, but is preferably the same as the content of each component in the solid content of the solid electrolyte-containing composition for a secondary battery of the present invention. The layer thickness of each layer constituting the solid electrolyte sheet for an all-solid-state secondary battery is the same as the layer thickness of each layer described in the all-solid-state secondary battery described below.

[0129] The substrate is not particularly limited as long as it can support the solid electrolyte layer, and examples thereof include sheets (plates) of materials described below in relation to the current collector, organic materials, inorganic materials, etc. Examples of organic materials include various polymers, specifically polyethylene terephthalate, polypropylene, polyethylene, cellulose, etc. Examples of inorganic materials include glass, ceramics, etc.

[0130] The electrode sheet for an all-solid-state secondary battery of the present invention (also simply referred to as "electrode sheet") may be an electrode sheet having an active material layer. It may be a sheet in which the active material layer is formed on a substrate (current collector), or a sheet formed from the active material layer without a substrate (a sheet from which the substrate has been peeled off). This electrode sheet typically has a current collector and an active material layer, but embodiments having a current collector, active material layer, and solid electrolyte layer in this order are also included. It is also possible to have a current collector, active material layer, solid electrolyte layer, and active material layer in this order. The active material layer, and optionally the solid electrolyte layer, of the electrode sheet is preferably formed from the solid electrolyte-containing composition for a secondary battery of the present invention. The content of each component in this solid electrolyte layer or active material layer is not particularly limited, but is preferably synonymous with the content of each component in the solid content of the solid electrolyte-containing composition for a secondary battery of the present invention. The layer thickness of each layer constituting the electrode sheet of the present invention is the same as the layer thickness of each layer described in the all-solid-state secondary battery described below. The electrode sheet may also have other layers as described above. When the solid electrolyte layer or the active material layer is not formed from the solid electrolyte-containing composition for a secondary battery of the present invention, it is formed from a normal constituent layer forming material.

[0131] In the sheet for an all-solid-state secondary battery of the present invention, at least one of the constituent layers is formed from the solid electrolyte-containing composition for a secondary battery of the present invention. Therefore, the sheet for an all-solid-state secondary battery of the present invention has a constituent layer that firmly binds solid particles while suppressing an increase in the interfacial resistance of the solid particles. Therefore, by incorporating this constituent layer into an all-solid-state secondary battery, low resistance (high conductivity) of the all-solid-state secondary battery can be achieved. The sheet for an all-solid-state secondary battery of the present invention is suitably used as a sheet-like member to be incorporated as a constituent layer of an all-solid-state secondary battery.

[0132] [Method for Manufacturing Sheet for All-Solid-State Secondary Battery] The method for manufacturing the sheet for an all-solid-state secondary battery of the present invention is not particularly limited, and the sheet can be manufactured by forming the above-mentioned constituent layer using the solid electrolyte-containing composition for a secondary battery of the present invention. A preferred method is to form a layer (coated and dried) composed of the solid electrolyte-containing composition for a secondary battery on a substrate or a current collector (optionally via another layer) by film formation (coating and drying). This allows the production of a sheet for an all-solid-state secondary battery having a substrate or a current collector and a coated and dried layer. Here, the coated and dried layer refers to a layer formed by coating the solid electrolyte-containing composition for a secondary battery of the present invention and drying the dispersion medium and organic solvent (i.e., a layer formed using the solid electrolyte-containing composition for a secondary battery of the present invention and consisting of a composition obtained by removing the dispersion medium and organic solvent from the solid electrolyte-containing composition for a secondary battery of the present invention). The constituent layer and the coated and dried layer may contain residual dispersion medium and organic solvent as long as the effects of the present invention are not impaired. The residual amount can be, for example, 3% by mass or less in each layer. In the method for manufacturing a sheet for an all-solid-state secondary battery of the present invention, each step, such as coating and drying, is described below in the method for manufacturing an all-solid-state secondary battery.

[0133] In the method for producing a sheet for an all-solid-state secondary battery of the present invention, the coated and dried layer obtained as described above can also be pressed. The pressing conditions and the like will be explained in the method for producing an all-solid-state secondary battery described below. In addition, in the method for producing a sheet for an all-solid-state secondary battery of the present invention, the substrate, the protective layer (particularly the release sheet), and the like can also be peeled off.

[0134] [Non-aqueous Secondary Battery] The non-aqueous secondary battery of the present invention has a positive electrode active material layer, a negative electrode active material layer facing the positive electrode active material layer, and an electrolyte layer disposed between the positive electrode active material layer and the negative electrode active material layer. The non-aqueous secondary battery of the present invention is not particularly limited in its configuration, as long as it has an electrolyte layer between the positive electrode active material layer and the negative electrode active material layer, and can employ, for example, a known configuration related to non-aqueous secondary batteries. <All-Solid-State Secondary Battery> The following describes an all-solid-state secondary battery, which is a preferred embodiment of a non-aqueous secondary battery. The all-solid-state secondary battery of the present invention has a positive electrode active material layer, a negative electrode active material layer facing the positive electrode active material layer, and a solid electrolyte layer disposed between the positive electrode active material layer and the negative electrode active material layer. The all-solid-state secondary battery of the present invention is not particularly limited in its configuration, as long as it has a solid electrolyte layer between the positive electrode active material layer and the negative electrode active material layer, and can employ, for example, a known configuration related to all-solid-state secondary batteries. The positive electrode active material layer is preferably formed on a positive electrode current collector to form a positive electrode. The negative electrode active material layer is preferably formed on a negative electrode current collector to constitute the negative electrode. In the present invention, each of the constituent layers (including the current collector, etc.) constituting the all-solid-state secondary battery may have a single-layer structure or a multi-layer structure.

[0135] It is preferred that at least one of the solid electrolyte layer, the anode active material layer, and the cathode active material layer be formed from the solid electrolyte-containing composition for a secondary battery of the present invention. Another preferred embodiment is that the solid electrolyte layer and either the anode active material layer or the cathode active material layer are all formed from the solid electrolyte-containing composition for a secondary battery of the present invention. Another preferred embodiment is that both the anode active material layer and the cathode active material layer are formed from the solid electrolyte-containing composition for a secondary battery of the present invention. It is also preferred that either one of the anode (a laminate of an anode current collector and an anode current collector) and the cathode (a laminate of a cathode current collector and a cathode current collector) be formed from the electrode sheet for an all-solid-state secondary battery of the present invention, and both be formed from the electrode sheet for an all-solid-state secondary battery of the present invention. In another preferred embodiment of the present invention, all layers are formed from the solid electrolyte-containing composition for a secondary battery of the present invention. In the present invention, forming the constituent layers of an all-solid-state secondary battery from the solid electrolyte-containing composition for secondary batteries of the present invention includes an embodiment in which the constituent layers are formed from the sheet for all-solid-state secondary batteries of the present invention (however, if a layer other than the layer formed from the solid electrolyte-containing composition for secondary batteries of the present invention is present, the sheet is formed from this layer removed). Note that when the active material layer or the solid electrolyte layer is not formed from the solid electrolyte-containing composition for secondary batteries of the present invention, known materials can be used. In the present invention, each constituent layer (including the current collector, etc.) constituting the all-solid-state secondary battery may have a single-layer structure or a multi-layer structure.

[0136] <Positive Electrode Active Material Layer, Solid Electrolyte Layer, Negative Electrode Active Material Layer> The solid electrolyte layer and active material layer formed from the solid electrolyte-containing composition for a secondary battery of the present invention preferably have the same component types and contents as those of the solid content of the solid electrolyte-containing composition for a secondary battery of the present invention. The thicknesses of the negative electrode active material layer, solid electrolyte layer, and positive electrode active material layer are not particularly limited. Taking into account the dimensions of a typical 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 invention, it is even more preferable that the thickness of any layer is 50 μm or more and less than 500 μm.

[0137] <Current Collector> The positive electrode active material layer and the negative electrode active material layer may each have a current collector on the side opposite to the solid electrolyte layer. The positive electrode current collector and the negative electrode current collector are preferably electronic conductors. In the present invention, either the positive electrode current collector or the negative electrode current collector, or both of them together, may be simply referred to as a current collector. Materials for forming the positive electrode current collector include aluminum, aluminum alloys, stainless steel, nickel, titanium, etc., as well as aluminum or stainless steel surfaces treated with carbon, nickel, titanium, or silver (thin films formed thereon), with aluminum and aluminum alloys being more preferred. Materials for forming the negative electrode current collector include aluminum, copper, copper alloys, stainless steel, nickel, titanium, etc., as well as aluminum, copper, copper alloys, or stainless steel surfaces treated with carbon, nickel, titanium, or silver, with aluminum, copper, copper alloys, and stainless steel being more preferred.

[0138] The current collector is usually in the form of a film sheet, but nets, punched materials, lath materials, porous materials, foamed materials, and molded fiber bodies can also be used. The thickness of the current collector is not particularly limited, but is preferably 1 to 500 μm. It is also preferable to make the surface of the current collector uneven by surface treatment.

[0139] <Other Configurations> In the present invention, functional layers or members may be appropriately interposed or disposed between or on the outside of the negative electrode current collector, negative electrode active material layer, solid electrolyte layer, positive electrode active material layer, and positive electrode current collector.

[0140] <Housing> Depending on the application, the all-solid-state secondary battery of the present invention may be used as an all-solid-state secondary battery with the above structure as it is, but it is preferable to further encapsulate it in an appropriate housing to make it into a dry battery. The housing may be made of metal or resin (plastic). When a metallic housing is used, examples include aluminum alloys and stainless steel. The metallic housing is preferably divided into a positive electrode housing and a negative electrode housing, and is electrically connected to the positive electrode current collector and the negative electrode current collector, respectively. The positive electrode housing and the negative electrode housing are preferably joined and integrated via a gasket to prevent short circuits.

[0141] <Preferred Embodiment of All-Solid State Secondary Battery> Hereinafter, an all-solid state secondary battery according to a preferred embodiment of the present invention will be described with reference to FIG. 1, but the present invention is not limited thereto.

[0142] FIG. 1 is a cross-sectional view schematically illustrating an all-solid-state secondary battery (lithium ion secondary battery) according to a preferred embodiment of the present invention. The all-solid-state secondary battery 10 of this embodiment has, as viewed from the negative electrode side, a negative electrode current collector 1, a negative electrode active material layer 2, a solid electrolyte layer 3, a positive electrode active material layer 4, and a positive electrode current collector 5, in this order. Each layer is in contact with each other and has an adjacent structure. By adopting such a structure, electrons (e － ) is supplied to the battery, and lithium ions (Li ＋ On the other hand, during discharge, the lithium ions (Li ＋ ) is returned to the positive electrode side, and electrons are supplied to the operating part 6. In the illustrated example, a light bulb is used as a model for the operating part 6, and it is lit by discharge.

[0143] When an all-solid-state secondary battery having the layer structure shown in FIG. 1 is placed in a 2032-type coin case 11, this all-solid-state secondary battery is referred to as a laminated body 12 for an all-solid-state secondary battery, and a battery produced by placing this laminated body 12 for an all-solid-state secondary battery in a 2032-type coin case 11 is sometimes referred to as a (coin-type) all-solid-state secondary battery 13.

[0144] (Positive Electrode Active Material Layer, Solid Electrolyte Layer, Negative Electrode Active Material Layer) In the all-solid-state secondary battery 10, the positive electrode active material layer, solid electrolyte layer, and negative electrode active material layer are all formed from the solid electrolyte-containing composition for secondary batteries of the present invention. The inorganic solid electrolyte, polymer binder, and metal element-containing component contained in the positive electrode active material layer 4, solid electrolyte layer 3, and negative electrode active material layer 2 may be the same or different from each other. Furthermore, the conductive additives contained in the positive electrode active material layer 4 and negative electrode active material layer 2 may be the same or different from each other. In the present invention, either the positive electrode active material layer or the negative electrode active material layer, or both together, may be simply referred to as the active material layer or electrode active material layer. Furthermore, either the positive electrode active material or the negative electrode active material, or both together, may be simply referred to as the active material or electrode active material.

[0145] The solid electrolyte layer contains an inorganic solid electrolyte having ion conductivity of a metal belonging to Group 1 or 2 of the periodic table, the above-mentioned polymer binder, the above-mentioned metal element-containing component, and the above-mentioned optional components, etc., to the extent that the effects of the present invention are not impaired. It typically does not contain a positive electrode active material and / or a negative electrode active material. The positive electrode active material layer contains an inorganic solid electrolyte having ion conductivity of a metal belonging to Group 1 or 2 of the periodic table, the above-mentioned polymer binder, the above-mentioned metal element-containing component, a positive electrode active material, preferably a conductive additive, and the above-mentioned optional components, etc., to the extent that the effects of the present invention are not impaired. The negative electrode active material layer contains an inorganic solid electrolyte having ion conductivity of a metal belonging to Group 1 or 2 of the periodic table, the above-mentioned polymer binder, the above-mentioned metal element-containing component, a negative electrode active material, preferably a conductive additive, and the above-mentioned optional components, etc., to the extent that the effects of the present invention are not impaired. In the all-solid-state secondary battery 10, the negative electrode active material layer can be a lithium metal layer. Examples of the lithium metal layer include a layer formed by depositing or molding lithium metal powder, lithium foil, and a lithium vapor-deposited film. The thickness of the lithium metal layer can be, for example, 1 to 500 μm, regardless of the thickness of the negative electrode active material layer.

[0146] In the present invention, when a constituent layer is formed from the solid electrolyte-containing composition for a secondary battery of the present invention, a low-resistance all-solid-state secondary battery can be realized. Furthermore, since the all-solid-state secondary battery of the present invention has low resistance, it is also possible to extract a large current.

[0147] (Current Collector) The positive electrode current collector 5 and the negative electrode current collector 1 are as described above. When the all-solid-state secondary battery 10 has a constituent layer other than the constituent layer formed from the solid electrolyte-containing composition for a secondary battery of the present invention, a layer formed from a known constituent layer-forming material can also be applied. Furthermore, each layer may be composed of a single layer or multiple layers.

[0148] [Manufacturing of Nonaqueous Secondary Battery] A nonaqueous secondary battery can be manufactured by a conventional method using the constituent layer-forming material of the present invention. For example, an all-solid-state secondary battery can be manufactured by forming the above-mentioned layers using the solid electrolyte-containing composition for secondary batteries of the present invention. Specifically, the all-solid-state secondary battery of the present invention can be manufactured by a method (a manufacturing method for an all-solid-state secondary battery sheet of the present invention) that includes (intervenes) a step of applying the solid electrolyte-containing composition for secondary batteries of the present invention to a suitable substrate (e.g., a metal foil serving as a current collector) and forming a coating film. More specifically, a positive electrode composition containing a positive electrode active material is applied and dried on a metal foil serving as a positive electrode current collector to form a positive electrode active material layer, thereby producing a positive electrode sheet for an all-solid-state secondary battery. Next, a solid electrolyte-containing composition for forming a solid electrolyte layer is applied and dried on this positive electrode active material layer to form a solid electrolyte layer. Furthermore, a negative electrode composition containing a negative electrode active material is applied and dried on the solid electrolyte layer to form a negative electrode active material layer. By overlaying a negative electrode current collector (metal foil) on the negative electrode active material layer, an all-solid-state secondary battery can be obtained in which a solid electrolyte layer is sandwiched between a positive electrode active material layer and a negative electrode active material layer. This can also be enclosed in a case to form a desired all-solid-state secondary battery. Alternatively, the method of forming each layer can be reversed, and an all-solid-state secondary battery can be produced by forming a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer on the negative electrode current collector, and then overlaying the positive electrode current collector.

[0149] Another method includes the following. That is, a positive electrode sheet for an all-solid-state secondary battery is prepared as described above. A negative electrode composition containing a negative electrode active material is applied as a negative electrode material to a metal foil serving as a negative electrode current collector and dried to form a negative electrode active material layer, thereby preparing a negative electrode sheet for an all-solid-state secondary battery. Next, a solid electrolyte layer is formed on the active material layer of either of these sheets as described above. Furthermore, the other of the positive electrode sheet for an all-solid-state secondary battery and the negative electrode sheet for an all-solid-state secondary battery is laminated on the solid electrolyte layer so that the solid electrolyte layer and the active material layer are in contact with each other. In this way, an all-solid-state secondary battery can be manufactured. Another method includes the following. That is, a positive electrode sheet for an all-solid-state secondary battery and a negative electrode sheet for an all-solid-state secondary battery are prepared as described above. Separately from this, a solid electrolyte-containing composition is applied to a substrate to prepare a solid electrolyte sheet for an all-solid-state secondary battery comprising a solid electrolyte layer. Furthermore, the solid electrolyte layer peeled from the substrate is sandwiched between the positive electrode sheet for an all-solid-state secondary battery and the negative electrode sheet for an all-solid-state secondary battery. In this way, an all-solid-state secondary battery can be manufactured.

[0150] Furthermore, a positive electrode sheet for an all-solid-state secondary battery or a negative electrode sheet for an all-solid-state secondary battery, and a solid electrolyte sheet for an all-solid-state secondary battery are produced as described above. Next, the positive electrode sheet for an all-solid-state secondary battery or the negative electrode sheet for an all-solid-state secondary battery and the solid electrolyte sheet for an all-solid-state secondary battery are overlapped with each other in a state in which the positive electrode active material layer or the negative electrode active material layer is in contact with the solid electrolyte layer, and pressurized. In this way, the solid electrolyte layer is transferred to the positive electrode sheet for an all-solid-state secondary battery or the negative electrode sheet for an all-solid-state secondary battery. Thereafter, the solid electrolyte layer from which the substrate of the solid electrolyte sheet for an all-solid-state secondary battery has been peeled is overlapped with the negative electrode sheet for an all-solid-state secondary battery or the positive electrode sheet for an all-solid-state secondary battery (in a state in which the negative electrode active material layer or the positive electrode active material layer is in contact with the solid electrolyte layer) and pressurized. In this way, an all-solid-state secondary battery can be produced. The pressurization method and pressurization conditions in this method are not particularly limited, and the method and pressurization conditions described in the pressurization step below can be applied.

[0151] The solid electrolyte layer or the like can also be formed, for example, by pressure molding a solid electrolyte-containing composition or the like on a substrate or an active material layer under pressure conditions described below. In the above-mentioned manufacturing method, the solid electrolyte-containing composition for a secondary battery of the present invention may be used for any of the solid electrolyte-containing composition, the positive electrode composition, and the negative electrode composition, and the solid electrolyte-containing composition for a secondary battery of the present invention can also be used for all of the compositions. When the solid electrolyte layer or the active material layer is formed using a composition other than the solid electrolyte-containing composition for a secondary battery of the present invention, examples of the material include commonly used compositions. Alternatively, instead of forming a negative electrode active material layer during the manufacturing of an all-solid-state secondary battery, the negative electrode active material layer can be formed by bonding ions of a metal belonging to Group 1 or Group 2 of the periodic table, which have accumulated in the negative electrode current collector during initialization or charging during use (described below), with electrons and depositing the metal on the negative electrode current collector or the like.

[0152] <Formation of Each Layer (Film Formation)> The coating method of the constituent layer-forming material is not particularly limited and can be selected appropriately. Examples include coating (preferably wet coating), spray coating, spin coating, dip coating, slit coating, stripe coating, and bar coating. The coating temperature is not particularly limited and can be, for example, a temperature range of about room temperature (e.g., 15 to 30°C) without heating. In this case, the solid electrolyte-containing composition for a secondary battery may be dried after each coating, or may be dried after multilayer coating. The drying temperature is not particularly limited. The lower limit is preferably 30°C or higher, more preferably 60°C or higher, and even more preferably 80°C or higher. The upper limit is preferably 300°C or lower, more preferably 250°C or lower, and even more preferably 200°C or lower. Heating within this temperature range allows the dispersion medium and organic solvent to be removed and a solid state (coated, dried layer) to be formed. Furthermore, it is preferable not to raise the temperature too high, as this avoids damaging the components of the nonaqueous secondary battery. This allows the nonaqueous secondary battery to exhibit excellent overall performance, and also to obtain good binding properties and good ionic conductivity.

[0153] After applying the constituent layer-forming material, after stacking the constituent layers, or after fabricating the nonaqueous secondary battery, it is preferable to pressurize each layer or the nonaqueous secondary battery. It is also preferable to pressurize the layers in a stacked state. Examples of pressurizing methods include a hydraulic cylinder press. The pressure is not particularly limited, and is generally in the range of 5 to 1500 MPa. The applied constituent layer-forming material may be heated simultaneously with the pressurization. The heating temperature is not particularly limited, and is generally in the range of 30 to 300°C. It is also possible to press at a temperature higher than the glass transition temperature of the inorganic solid electrolyte. It is also possible to press at a temperature higher than the glass transition temperature of the polymer contained in the polymer binder. However, the temperature is generally not higher than the melting point of the polymer. Pressurization may be performed after the application solvent or dispersion medium and organic solvent have been dried in advance, or while the solvent or dispersion medium and organic solvent remain. The compositions may be applied simultaneously, or the application, drying, and pressing may be performed simultaneously and / or sequentially. After coating on separate substrates, the compositions may be laminated by transfer.

[0154] The atmosphere in the film-forming method (coating, drying, and pressurization (under heating)) is not particularly limited, and may be any of the following: atmospheric air, dry air (dew point -20°C or lower), and inert gas (e.g., argon gas, helium gas, nitrogen gas). High pressure may be applied for a short period of time (e.g., within a few hours), or moderate pressure may be applied for a long period of time (one day or more). In the case of a sheet other than an all-solid-state secondary battery sheet, for example, an all-solid-state secondary battery, a restraining device for the all-solid-state secondary battery (e.g., screw tightening pressure) may be used to continuously apply moderate pressure. The pressing pressure may be uniform or may vary across the pressed portion, such as the sheet surface. The pressing pressure may be varied depending on the area or film thickness of the pressed portion. The same portion may also be subjected to different pressures in stages. The pressing surface may be smooth or roughened.

[0155] <Initialization> The nonaqueous secondary battery produced as described above is preferably initialized after production or before use. The initialization is not particularly limited, and can be performed, for example, by performing initial charge / discharge under an elevated pressure and then releasing the pressure until the pressure reaches the normal operating pressure for nonaqueous secondary batteries.

[0156] [Uses of Nonaqueous Secondary Battery] The nonaqueous secondary battery of the present invention can be used in a variety of applications. While there are no particular limitations on the application, examples of applications include electronic devices such as notebook computers, pen-input PCs, mobile PCs, electronic book players, mobile phones, cordless phone handsets, pagers, handheld terminals, portable fax machines, portable copiers, portable printers, headphone stereos, video camcorders, LCD televisions, handheld vacuum cleaners, portable CD players, mini-discs, electric shavers, transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, and backup power supplies. Other consumer applications include automobiles (e.g., electric vehicles), electric vehicles, motors, lighting fixtures, toys, game consoles, road conditioners, clocks, flash devices, cameras, and medical devices (e.g., pacemakers, hearing aids, and shoulder massagers). Furthermore, the battery can be used for various military and space applications. It can also be combined with solar cells.

[0157] The present invention will be described in more detail below based on examples, but the present invention should not be construed as being limited thereto. In the following examples, "parts" and "%" representing compositions are based on mass unless otherwise specified. In the present invention, "room temperature" means 25°C.

[0158] Example 1 In Example 1, various compositions and sheets for all-solid-state secondary batteries were prepared or fabricated, all-solid-state secondary batteries were manufactured, and the battery characteristics of the all-solid-state secondary batteries were evaluated.

[0159] 1. Synthesis of Polymers and Preparation of Binder Compositions Polymers P1 to P24, P27 to P33, and T1 to T5 shown in Tables 1-1 and 1-2 (collectively referred to as Table 1) below were synthesized as follows.

[0160] [Synthesis Example P1] Synthesis of Polymer P1 To a 100 mL graduated cylinder, 10 g of lauryl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) and 1 g of polymerization initiator V-601 (trade name, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added and dissolved in 10 g of butyl butyrate to prepare a monomer solution. 30 g of butyl butyrate was added to a 300 mL three-necked flask and stirred at 80 ° C., and the monomer solution was added dropwise over 2 hours. After completion of the dropwise addition, the temperature was raised to 90 ° C. and stirred for 2 hours. The obtained polymerization solution was poured into 100 g of methanol, stirred for 10 minutes, and then allowed to stand for 10 minutes. The precipitate obtained after removing the supernatant was dissolved in 15 g of butyl butyrate, and the methanol was distilled off by heating at 30 hPa and 60 ° C. for 1 hour. In this way, polymer P1 was synthesized, and a solution P1 of this polymer (concentration 40% by mass) was obtained.

[0161] [Synthesis Examples P2 to P24, P28 to P32, and T1 to T5] Synthesis of Polymers P2 to P24, P28 to P32, and T1 to T5 Polymers P2 to P24, P28 to P32, and T1 to T5 were synthesized in the same manner as in Synthesis Example P1, except that in Synthesis Example P1, compounds were used that would lead to each constituent so that polymers P2 to P24, P28 to P32, and T1 to T5 each had the composition (type and content of constituents) shown in Table 1 below, and the amount of polymerization initiator was appropriately adjusted so that the weight-average molecular weight would be as shown in Table 1, and solutions of each polymer P2 to P24, P28 to P32, and T1 to T5 (all with a concentration of 40% by mass) were obtained. Note that polymer P11 was a monomethyl ester formed by cleavage of the acid anhydride group in the constituent derived from maleic acid through reaction with methanol.

[0162] [Synthesis Example P27] Synthesis of Polymer P27 An autoclave was charged with 500 parts of n-butyl acrylate, 200 parts of styrene, 5 parts of methacrylic acid, 10 parts of divinylbenzene, 25 parts of polyoxyethylene lauryl ether (Kao Corporation, Emulgen 108) as an emulsifier, 1500 parts of ion-exchanged water, and 15 parts of azobisbutyronitrile as a polymerization initiator, and the mixture was thoroughly stirred. The mixture was then heated to 80°C to polymerize. After polymerization initiation, the mixture was cooled to terminate the polymerization reaction, and the solvent was then replaced with butyl butyrate to synthesize Polymer P27. Latex P27 (concentration 30% by mass, referred to as "Latex A" in Table 1) was obtained from these polymer particles. In this latex P27, the content of the component MA derived from methacrylic acid was 0.7% by mass.

[0163] Preparation Examples S-1 to S-24, S-27 to S-32, and T-1 to T-5 Preparation of binder compositions S-1 to S-24, S-27 to S-32, and T-1 to T-5 At room temperature, the metal element-containing component shown in Table 1 was added to the polymer solutions P1 to P24, P27 to P32, and T1 to T5 synthesized in the above Synthesis Examples P1 to P24, P27 to P32, and T1 to T5 in an amount of C ＭＢ The solid content of the polymer is added in a ratio of 0.01 to 0.01, and the solid content of the polymer is 0.01 to 0.01 in the "Polymer binder" column of Table 1. ＰＢ The binder compositions S-1 to S-24, S-27 to S-32, and T-1 to T-5 were prepared by appropriately adjusting the content of the dispersion medium shown in Table 1 and mixing them so as to obtain the content shown in the "" column. The prepared binder composition T-1 does not contain a metal element-containing component having a particle size of 10 μm or less.

[0164] Preparation Examples S-25, S-26, and S-33 Preparation of Binder Compositions S-25, S-26, and S-33 At room temperature, polyester A (polycaprolactone, manufactured by Aldrich), polycarbonate A (polypropylene carbonate, manufactured by Aldrich), or SEBS copolymer (Septon 8004, manufactured by Kuraray Co., Ltd., referred to as "SEBS" in Table 1) as polymer P33, and the metal element-containing component shown in Table 1-2 were mixed together in a binder solution until the solids concentration of the polymer reached the "Content C" in the "Polymer binder" column in Table 1-2. ＰＢ" column, and the content of the metal element-containing component is the content C shown in Table 1-2. ＭＢ The dispersion media shown in Table 1-2 were appropriately used and mixed so as to prepare binder compositions S-25, S-26 and S-33, respectively.

[0165] Details of each binder composition are shown in Table 1. The type, content, and weight average molecular weight (measured by the above method) of the constituent components constituting each synthesized polymer are shown in the "Polymer binder" column of Table 1. Also, the "Content C ＰＢ " indicates the content (solid concentration) of the polymer binder in the binder composition. The unit of "content" in Table 1 is content C ＭＢ All values ​​other than those listed are in mass %, but are omitted in Table 1. In addition, "HMCTS" in the "Metal Element-Containing Component" column of Table 1 represents hexamethylcyclotrisiloxane. The "State" column in the same column shows the state of the metal element-containing component in the binder composition (dissolved (represented as "dissolved" in Table 1) or insoluble and dispersed in particulate form (represented as "particles" in Table 1)) as confirmed by the above method. When the metal element-containing component exists in the form of particles, the particle size measured by the above method is also listed. In binder compositions S-1 to S-15, S-18 to S-28, S-33, T-3, and T-4, each metal element-containing component with a particle size of 0.1 μm was used, but binder compositions S-14 and S-15 contained a high content and therefore did not dissolve, and existed in the form of particles that maintained their particle size. Furthermore, in binder compositions S-16, S-29, T-2, and T-5, alumina having the particle size shown in Table 1 was used (in binder composition T-2, the particle size was large, so even though the content was small, it did not dissolve and existed in particulate form. On the other hand, in S-29 and T-5, the content was large, so it did not dissolve and existed in particulate form while maintaining its particle size). In binder compositions S-30 to S-32, the hexamethylcyclotrisiloxane used dissolved in the composition. Furthermore, the content C of the polymer binder in each binder composition ＰＢ Content C of metal element-containing component relative to ＭＢ The ratio [C ＭＢ / C ＰＢ] is calculated and the "ratio [C ＭＢ / C ＰＢ The results are shown in the "Table 1." All of the binder compositions using polymer solutions were water-insoluble compositions, and the polymer binder was dissolved in a dispersion medium.

[0166]

[0167]

[0168] In the tables, a "-" in the component column indicates that the corresponding component is not present. Components A, MA, and MC respectively represent the other components described above, component MA, and polar functional group-containing component MC. However, for binder compositions S-25 to S-27 and S-33, each polymer is listed in the component A column for convenience. Phosmer M is 2-(methacryloyloxy)ethyl phosphate (manufactured by Unichemical Co., Ltd.).

[0169] 2. Synthesis of sulfide-based inorganic solid electrolyte [Synthesis Example A] The sulfide-based inorganic solid electrolyte was synthesized with reference to the non-patent literature of T. Ohtomo, A. Hayashi, M. Tatsumisago, Y. Tsuchida, S. Hama, K. Kawamoto, Journal of Power Sources, 233, (2013), pp. 231-235, and A. Hayashi, S. Hama, H. Morimoto, M. Tatsumisago, T. Minami, Chem. Lett., (2001), pp. 872-873. Specifically, lithium sulfide (Li ２ S, manufactured by Aldrich, purity >99.98%) 2.42 g and diphosphorus pentasulfide (P ２ S ５ 3.90 g of Li, manufactured by Aldrich, purity >99%) was weighed out and placed in an agate mortar and mixed for 5 minutes using an agate pestle. ２ S and P ２ S ５ The mixing ratio is Li in molar ratio. ２ S:P ２ S ５= 75:25. Next, 66 g of zirconia beads having a diameter of 5 mm was added to a 45 mL zirconia container (manufactured by Fritsch), and the entire amount of the mixture of lithium sulfide and diphosphorus pentasulfide was added, and the container was completely sealed under an argon atmosphere. The container was set in a planetary ball mill P-7 (trade name, manufactured by Fritsch), and mechanical milling was performed for 20 hours at a temperature of 25 ° C. and a rotation speed of 510 rpm to obtain 6.20 g of a yellow powder sulfide-based inorganic solid electrolyte (Li-P-S-based glass, hereinafter sometimes referred to as LPS). The particle diameter of the Li-P-S-based glass was 15 μm.

[0170] 3. Preparation of Solid Electrolyte-Containing Compositions for Secondary Batteries Using the binder compositions prepared above, the solid electrolyte-containing compositions for secondary batteries shown in Tables 2-1 to 2-4 (collectively referred to as Table 2) were prepared as follows. <Preparation of Inorganic Solid Electrolyte-Containing Compositions> 60 g of zirconia beads with a diameter of 5 mm were placed in a 45 mL zirconia container (manufactured by Fritsch), and 7.88 g of the LPS synthesized in Synthesis Example A above, 0.12 g (solid content by mass) of the binder composition shown in Table 2-1 or Table 2-4, and 12 g (total amount) of the dispersion medium (including the dispersion medium derived from the binder composition) shown in Table 2-1 or Table 2-4 were placed. The container was then placed in a planetary ball mill P-7 (trade name). Mixing was performed for 10 minutes at a temperature of 25°C and a rotation speed of 150 rpm to prepare inorganic solid electrolyte-containing compositions (slurries) K-1 to K-33 and Kc11 to Kc15, respectively.

[0171] <Preparation of Positive Electrode Composition> 60 g of zirconia beads having a diameter of 5 mm were placed in a 45 mL zirconia container (manufactured by Fritsch), and 4.58 g of the LPS synthesized in Synthesis Example A and 12.00 g (total amount) of the dispersion medium (including the organic solvent derived from the binder composition) shown in Table 2-2 or Table 2-4 were placed in. Thereafter, this container was placed in a planetary ball mill P-7 (trade name), and the mixture was stirred at 25°C and 200 rpm for 30 minutes. Next, 3.2 g of NMC (manufactured by Aldrich Chemical Co.) as the positive electrode active material, 0.14 g of acetylene black (AB) as a conductive additive, and 0.08 g (solid content by mass) of a binder composition shown in Table 2-2 or Table 2-4 were added to this container, and the container was set in a planetary ball mill P-7 (trade name). Mixing was continued for 30 minutes at a temperature of 25°C and a rotation speed of 200 rpm to prepare positive electrode compositions (slurries) PK-1 to PK-33 and PKc21 to PKc25, respectively.

[0172] <Preparation of Negative Electrode Composition> 60 g of zirconia beads having a diameter of 5 mm were placed in a 45 mL zirconia container (manufactured by Fritsch), and 3.6 g of the LPS synthesized in Synthesis Example A, 0.08 g (solid content by mass) of the binder composition shown in Table 2-3 or Table 2-4, and 12 g (total amount) of the dispersion medium (including the organic solvent derived from the binder composition) shown in Table 2-3 or Table 2-4 were placed in. Thereafter, this container was set in a planetary ball mill P-7 (trade name), and the mixture was mixed for 60 minutes at a temperature of 25°C and a rotation speed of 300 rpm. Next, 4.0 g of silicon (Si) was added as the negative electrode active material and 0.32 g of VGCF (manufactured by Showa Denko K.K.) as a conductive additive, and the container was similarly set in a planetary ball mill P-7 (trade name) and mixed for 10 minutes at a temperature of 25°C and a rotation speed of 100 rpm to prepare negative electrode compositions (slurries) NK-1 to NK-33 and NKc21 to NKc25, respectively.

[0173] In Table 2, the composition content is the content (mass%) relative to the total mass of each composition, and the solid content is the content (mass%) relative to 100 mass% of the solid content of each composition, and units are omitted in the table. Note that the "composition content" of the dispersion medium in Table 2 indicates the total amount including the content of the organic solvent derived from the binder composition. In addition, the content C of the metal element-containing component in each prepared composition ＭＳCalculate the content C in Table 2 ＭＳ The results are shown in the "." column. Each of the prepared compositions was a non-aqueous composition, and the polymer binder dissolved in the binder composition was also dissolved in the dispersion medium in each of the prepared compositions. Furthermore, the metal element-containing component was dissolved in each of the compositions using binder compositions S-1 to S-33 and T-3 to T-5, but the metal element-containing component was present as particles that maintained their particle size in each of the compositions using binder composition T-2.

[0174]

[0175]

[0176]

[0177]

[0178] LPS: LPS synthesized in Synthesis Example A NMC: LiNi １／３ Co １／３ Mn １／３ O ２ Si: Silicon (APS 1-5 μm, manufactured by Alfa Aesar) AB: Acetylene black VGCF: Carbon nanofiber

[0179] 4. Preparation of Sheets for All-Solid-State Secondary Batteries Sheets for all-solid-state secondary batteries were prepared as follows. <Preparation of Solid Electrolyte Sheets for All-Solid-State Secondary Batteries> Each of the inorganic solid electrolyte-containing compositions shown in the "Solid Electrolyte Composition No." column in Table 3-1 or Table 3-4 obtained above was applied to a 20 μm-thick aluminum foil using a Baker-type applicator (product name: SA-201, manufactured by Tester Sangyo Co., Ltd.) and heated at 80°C for 2 hours to dry the inorganic solid electrolyte-containing composition (removing the dispersion medium). The dried inorganic solid electrolyte-containing composition was then heated and pressed at a temperature of 120°C and a pressure of 40 MPa for 10 seconds using a heat press to prepare solid electrolyte sheets for all-solid-state secondary batteries (referred to as solid electrolyte sheets in Tables 3-1 and 3-4) 101 to 133 and c11 to c15, respectively. The film thickness of the solid electrolyte layer was 40 μm.

[0180] <Preparation of Positive Electrode Sheet for All-Solid State Secondary Battery> Each of the positive electrode compositions shown in the "Electrode Composition No." column in Table 3-2 or Table 3-4 obtained above was applied to a 20 μm-thick aluminum foil using a Baker-type applicator (product name: SA-201), heated at 80°C for 1 hour, and further heated at 110°C for 1 hour to dry the positive electrode composition (removing the dispersion medium). Thereafter, using a heat press, the dried positive electrode composition was pressed (10 MPa, 1 minute) at 25°C to prepare positive electrode sheets for all-solid state secondary batteries (referred to as positive electrode sheets in Tables 3-2 and 3-4) 201 to 233 and c21 to c25, respectively, having a positive electrode active material layer with a film thickness of 70 μm.

[0181] <Preparation of negative electrode sheets for all-solid-state secondary batteries> Each of the negative electrode compositions shown in the "Electrode composition No." column in Table 3-3 or Table 3-4 obtained above was applied to a copper foil having a thickness of 20 μm using a Baker-type applicator (product name: SA-201), heated at 80°C for 1 hour, and further heated at 110°C for 1 hour to dry the negative electrode composition (removing the dispersion medium). Thereafter, using a heat press, the dried negative electrode composition was pressed (10 MPa, 1 minute) at 25°C to prepare negative electrode sheets for all-solid-state secondary batteries (referred to as negative electrode sheets in Tables 3-3 and 3-4) 301 to 333 and c31 to c35, respectively, having a negative electrode active material layer with a film thickness of 60 μm.

[0182]

[0183]

[0184]

[0185]

[0186] 5. Production of All-Solid-State Secondary Battery First, a positive electrode sheet for an all-solid-state secondary battery having a solid electrolyte layer and a negative electrode sheet for an all-solid-state secondary battery having a solid electrolyte layer were produced, to be used in the production of an all-solid-state secondary battery.

[0187] - Preparation of cathode sheets for all solid state secondary batteries having solid electrolyte layer - On the cathode active material layer of each of the all solid state secondary battery cathode sheets shown in the "Electrode active material layer (sheet No.)" column of Tables 4-1 and 4-3, the solid electrolyte sheets prepared above and shown in the "Solid electrolyte layer (sheet No.)" column of Tables 4-1 and 4-3 were superimposed such that the solid electrolyte layer was in contact with the cathode active material layer, and the sheets were transferred (laminated) by pressing at 25°C and 50 MPa using a press, and then pressed at 25°C and 600 MPa to prepare cathode sheets for all solid state secondary batteries Nos. 201 to 233 and c21 to c25 (cathode active material layer thickness 50 μm) each having a solid electrolyte layer with a thickness of 25 μm.

[0188] - Preparation of negative electrode sheets for all solid state secondary batteries having solid electrolyte layer - On the negative electrode active material layer of each negative electrode sheet for all solid state secondary batteries shown in the "Electrode active material layer (sheet No.)" column of Tables 4-2 and 4-3, the solid electrolyte sheet prepared above and shown in the "Solid electrolyte layer (sheet No.)" column of Tables 4-2 and 4-3 was superimposed such that the solid electrolyte layer was in contact with the negative electrode active material layer, and a press was used to transfer (laminate) the sheets by applying pressure at 25°C and 50 MPa, followed by applying pressure at 25°C and 600 MPa to prepare negative electrode sheets for all solid state secondary batteries 301 to 333 and c31 to c35 (negative electrode active material layer thickness 40 μm) each having a solid electrolyte layer with a thickness of 25 μm.

[0189] All-solid-state secondary battery No. 401 having the layer structure shown in FIG. 1 was fabricated as follows. The all-solid-state secondary battery positive electrode sheet No. 201 (the aluminum foil of the solid electrolyte-containing sheet had already been peeled off) provided with the solid electrolyte layer obtained above was cut into a disk shape with a diameter of 14.5 mm and placed in a stainless steel 2032-type coin case 11 incorporating a spacer and a washer (not shown in FIG. 2 ) as shown in FIG. 2 . Next, a lithium foil (5 μm thick) cut into a disk shape with a diameter of 15 mm was placed on top of the solid electrolyte layer. A stainless steel foil (10 μm thick) was then placed on top of that, and the 2032-type coin case 11 was then crimped to fabricate all-solid-state secondary battery No. 401 13 shown in FIG. 2 . The all-solid-state secondary battery fabricated in this manner had the layer structure shown in FIG. 1 (where the lithium foil corresponds to the negative electrode active material layer 2 and the negative electrode current collector 1).

[0190] All solid state secondary batteries Nos. 402 to 435 and c101 to c105 were produced in the same manner as in the production of all solid state secondary battery No. 401, except that in the production of all solid state secondary battery No. 401, positive electrode sheets for all solid state secondary batteries having a solid electrolyte layer, represented by the numbers shown in the "Electrode active material layer (sheet No.)" column in Tables 4-1 and 4-3, were used instead of positive electrode sheet No. 201 for all solid state secondary batteries having a solid electrolyte layer.

[0191] All-solid-state secondary battery No. 501 having the layer structure shown in FIG. 1 was fabricated as follows. The solid electrolyte-containing negative electrode sheet No. 301 for all-solid-state secondary batteries obtained above (the aluminum foil of the solid electrolyte-containing sheet had already been peeled off) was cut into a disk shape with a diameter of 14.5 mm and placed in a stainless steel 2032-type coin case 11 incorporating a spacer and a washer (not shown in FIG. 2 ), as shown in FIG. 2 . Next, a positive electrode sheet (positive electrode active material layer) punched to a diameter of 14.0 mm from the positive electrode sheet for all-solid-state secondary batteries fabricated below was placed on top of the solid electrolyte layer. A stainless steel foil (positive electrode current collector) was further placed on top of this to form an all-solid-state secondary battery laminate 12 (a laminate consisting of stainless steel foil-aluminum foil-positive electrode active material layer-solid electrolyte layer-negative electrode active material layer-copper foil). The 2032-type coin case 11 was then crimped to produce all-solid-state secondary battery No. 501 shown in FIG. 2 .

[0192] The positive electrode sheet for a solid secondary battery used in the production of all-solid-state secondary battery No. 501 was prepared as follows. - Preparation of positive electrode composition - 180 zirconia beads with a diameter of 5 mm were placed in a 45 mL zirconia container (manufactured by Fritsch), and 2.7 g of the 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 content mass, and 22 g of butyl butyrate were added. This container was placed in a Fritsch planetary ball mill P-7 (trade name) and stirred at 25°C at 300 rpm for 60 minutes. Thereafter, LiNi was added as a positive electrode active material. １／３ Co １／３ Mn１／３ O ２ 7.0 g of (NMC) was added, and in the same manner, the container was set in a planetary ball mill P-7, and mixing was continued for 5 minutes at 25 ° C. and 100 rpm, to prepare a positive electrode composition. - Preparation of a positive electrode sheet for a solid secondary battery - The positive electrode composition obtained above was applied to a 20 μm thick aluminum foil (positive electrode current collector) using a Baker applicator (trade name: SA-201, manufactured by Tester Sangyo Co., Ltd.), heated at 100 ° C. for 2 hours, and the positive electrode composition was dried (dispersion medium removed). Thereafter, using a heat press, the dried positive electrode composition was pressurized (10 MPa, 1 minute) at 25 ° C. to prepare a positive electrode sheet for an all-solid-state secondary battery having a positive electrode active material layer with a film thickness of 80 μm.

[0193] All solid state secondary batteries Nos. 502 to 535 and c201 to c205 were produced in the same manner as in the production of all solid state secondary battery No. 501, except that in the production of all solid state secondary battery No. 501, negative electrode sheets for all solid state secondary batteries having a solid electrolyte layer, represented by the numbers shown in the "Electrode active material layer (sheet No.)" column in Tables 4-2 and 4-3, were used instead of negative electrode sheet No. 301 for all solid state secondary batteries having a solid electrolyte layer.

[0194] <Evaluation 1: Ionic Conductivity Measurement> The ionic conductivity of each of the manufactured all-solid-state secondary batteries was measured. Specifically, for each all-solid-state secondary battery, AC impedance was measured at a voltage amplitude of 5 mV and a frequency of 1 MHz to 1 Hz using a 1255B FREQUENCY RESPONSE ANALYZER (trade name, manufactured by SOLARTRON) in a thermostatic bath at 25°C. The resistance in the layer thickness direction of the ionic conductivity measurement sample was then determined, and the ionic conductivity was calculated using the following formula (C1). The results are shown in Tables 4-1 to 4-3 (collectively referred to as Table 4). Formula (C1): Ionic conductivity σ (mS / cm) = 1000 × sample layer thickness (cm) / [resistance (Ω) × sample area (cm)] ２) In formula (C1), the sample layer thickness is the value measured before placing the laminate 12 in the 2032-type coin case 11, and is the value obtained by subtracting the thickness of the current collector (total layer thickness of the solid electrolyte layer and the electrode active material layer). The sample area is the area of ​​a disk-shaped sheet with a diameter of 14.5 mm. It was determined whether the obtained ionic conductivity σ fell within any of the following evaluation criteria. In this test, an ionic conductivity σ of evaluation criterion "C" or higher is acceptable. As is clear from formula (C1) above, a high ionic conductivity σ means a low resistance. - Evaluation Criteria - A: 0.30≦σ B: 0.25≦σ<0.30 C: 0.20≦σ<0.25 D: 0.15≦σ<0.20 E: 0.10≦σ<0.15 F: σ<0.10

[0195]

[0196]

[0197]

[0198] The results shown in Tables 1 to 4 reveal the following: A polymer binder composed of a polymer having a component derived from (meth)acrylic acid in an amount of less than 30% by mass based on the total components of the polymer, and a 1.0 × 10 －３ ~1.0 x 10 ４Inorganic solid electrolyte-containing compositions using binder compositions T-1 to T-5, which do not contain a metal element-containing component with a particle size of 10 μm or less at a content of ppm, as a binder component, are unable to form a low-resistance constituent layer, and are unable to sufficiently achieve low resistance in all-solid-state secondary batteries. Specifically, compositions Kc11, PKc21, and NKc21, which use binder composition T-1, which does not use a metal element-containing component in combination with a polymer binder, enable low resistance in all-solid-state secondary batteries to a certain extent, but are unable to meet the advanced requirements of recent years. On the other hand, compositions Kc12, PKc22, and NKc22, which use binder composition T-2, which uses a metal element-containing component with a large particle size of 45 μm in combination with a polymer binder, are unable to suppress the increase in resistance in all-solid-state secondary batteries. Furthermore, in compositions Kc13, PKc23, and NKc23 using binder composition T-3, which uses a polymer binder composed of a polymer having 35% by mass of a component derived from (meth)acrylic acid in all the components of the polymer in combination with a metal element-containing component, it is believed that the polymer binder exhibits excessive cohesion, and as a result, it is not possible to suppress an increase in resistance of an all-solid-state secondary battery. In compositions Kc14, PKc24, and NKc24 using binder composition T-4, which contains too little metal element-containing component with a particle size of 10 μm or less, the effect of containing the metal element-containing component is insufficient, and it is not possible to suppress an increase in resistance of an all-solid-state secondary battery. On the other hand, in compositions Kc15, PKc25, and NKc25 using binder composition T-5, which contains too much metal element-containing component even though the particle size of the metal element-containing component is 10 μm or less, it is believed that the polymer binder is more likely to cohere due to the excessive coexistence of the metal element-containing component, and as a result, it is not possible to suppress an increase in resistance of an all-solid-state secondary battery.

[0199] On the other hand, a polymer binder composed of a polymer having a component derived from (meth)acrylic acid in an amount of less than 30 mass% of the total components of the polymer, and a 1.0 × 10 －３ ~1.0 x 10 ４Compositions K-1 to K-33, PK-1 to PK-33, and NK-1 to NK-33, which use binder compositions S-1 to S-33 containing a metal element-containing component with a particle size of 10 μm or less at a content of 1 ppm as the binder component, can be used as a constituent layer-forming material to form at least one constituent layer of a nonaqueous secondary battery, thereby effectively suppressing an increase in resistance and achieving a sufficiently low resistance (high ionic conductivity) all-solid-state secondary battery. Furthermore, if the binder-forming polymer has a polar functional group such as a carboxy group, the interaction with the metal element-containing component is strengthened, further enhancing the cohesiveness of the polymer binder, thereby enabling a further reduction in battery resistance.

[0200] While the present invention has been described in connection with embodiments thereof, we do not intend to limit our invention to any of the details of the description unless otherwise specified, and believe that the claims should be construed broadly without departing from the spirit and scope of the invention as set forth in the appended claims.

[0201] This application claims priority based on Japanese Patent Application No. 2022-100913 filed in Japan on June 23, 2022, and Japanese Patent Application No. 2023-081754 filed in Japan on May 17, 2023, the contents of which are incorporated herein by reference.

[0202] REFERENCE SIGNS LIST 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 operating part 10 all-solid-state secondary battery 11 2032-type coin case 12 laminate for all-solid-state secondary battery 13 coin-type all-solid-state secondary battery

Claims

1. A binder composition for a secondary battery, comprising a metal element-containing component having a particle size of 10 μm or less and a polymer binder, The content of the metal element-containing component in the composition is 1.0×10 －３ ~1.0 x 10 ４ ppm, A binder composition for a secondary battery, wherein a polymer forming the polymer binder has less than 30 mass % of a component derived from an ethylenically unsaturated carboxylic acid based on all components of the polymer.

2. 2. The binder composition for a secondary battery according to claim 1, wherein the metal element-containing component contains at least one metal element selected from the group consisting of Al, B, Ga, In, Si, and Ge.

3. 3. The binder composition for a secondary battery according to claim 1, wherein the polymer forming the polymer binder contains a component having at least one polar functional group selected from the following functional group group (a): <Polar functional group (a)> a sulfonic acid group, a phosphoric acid group, a phosphonic acid group, a hydroxy group, a carboxy group other than the carboxy group derived from the above-mentioned ethylenically unsaturated carboxylic acid, an oxetane group, an epoxy group, a dicarboxylic anhydride group, a thiol group, an ether group, a thioether group, a thioester group, a fluoroalkyl group, or a salt thereof

4. The binder composition for a secondary battery according to claim 1 or 2, wherein the polymer forming the polymer binder has a carboxy group.

5. 3. The binder composition for a secondary battery according to claim 1, wherein the polymer forming the polymer binder contains a component having a carboxy group in an amount of 0.1 to 10 mass % based on the total components of the polymer.

6. The weight average molecular weight of the polymer binder is 1.0×10 ４ ~1.0 x 10 ６ The binder composition for a secondary battery according to claim 1 or 2,

7. A solid electrolyte-containing composition for a secondary battery, comprising the binder composition for a secondary battery according to claim 1 and an inorganic solid electrolyte having ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, The content of the metal element-containing component in the solid electrolyte-containing composition for secondary batteries is 1.0×10 －３ ~1.0 x 10 ４ The solid electrolyte-containing composition for secondary batteries,

8. The solid electrolyte-containing composition for secondary batteries according to claim 7 , which contains an active material.

9. The solid electrolyte-containing composition for secondary batteries according to claim 7 , further comprising a conductive assistant.

10. A sheet for an all-solid-state secondary battery having a layer constituted of the solid electrolyte-containing composition for secondary batteries according to any one of claims 7 to 9.

11. A sheet for an all-solid-state secondary battery, comprising an active material layer made of the solid electrolyte-containing composition for secondary batteries according to claim 8 or 9.

12. An all-solid-state secondary battery having a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order, At least one of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer is a layer constituted by the solid electrolyte-containing composition for secondary batteries according to any one of claims 7 to 9. An all-solid-state secondary battery.

13. An all-solid-state secondary battery having a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order, 10. An all-solid-state secondary battery, wherein at least one of the positive electrode active material layer and the negative electrode active material layer is an active material layer constituted by the solid electrolyte-containing composition for secondary batteries according to claim 8 or 9.