Electrode composition, electrode sheet for all-solid-state secondary battery, and all-solid-state secondary battery, and manufacturing method of the three

Abstract

The present application provides an electrode composition capable of reducing the content of a polymer binder while achieving excellent dispersion properties and firm adhesion of solid particles, an electrode sheet for a full-solid-state secondary battery using the electrode composition, a full-solid-state secondary battery, and a manufacturing method for an electrode sheet for a full-solid-state secondary battery and a full-solid-state secondary battery. The electrode composition is an electrode composition containing an inorganic solid electrolyte, an active material, a polymer binder, and a dispersion medium, wherein the polymer binder includes: a polymer binder A that is dissolved in the dispersion medium, has an adsorption rate of 20% or more to the active material, and has a larger adsorption rate to the inorganic solid electrolyte; and a polymer binder B that is dissolved in the dispersion medium, has an adsorption rate of 20% or more to the inorganic solid electrolyte, and has a larger adsorption rate to the active material.

Description

Technical Field

[0001] This invention relates to an electrode composition, an electrode sheet for an all-solid-state secondary battery, an all-solid-state secondary battery, and a method for manufacturing the electrode composition, the electrode sheet for an all-solid-state secondary battery, and the all-solid-state secondary battery. Background Technology

[0002] In all-solid-state secondary batteries, the negative electrode, electrolyte, and positive electrode are all composed of solids, which can significantly improve the safety and reliability of batteries using organic electrolytes. It also extends battery life. Furthermore, all-solid-state secondary batteries can be configured with electrodes and electrolytes directly arranged and connected in series. Therefore, compared to secondary batteries using organic electrolytes, higher energy density can be achieved, and they hold promise for applications in electric vehicles or large-scale storage batteries.

[0003] In such all-solid-state secondary batteries, inorganic solid electrolytes and active materials can be cited as materials forming the active material layer (also called the electrode layer). These inorganic solid electrolytes, especially oxide-based and sulfide-based inorganic solid electrolytes, are expected to be electrolyte materials with high ionic conductivity approaching that of organic electrolytes.

[0004] As a material for forming the active material layer of an all-solid-state secondary battery (also referred to as an active material layer forming material or electrode composition), materials obtained by dispersing or dissolving the aforementioned inorganic solid electrolyte, active material, and binder (adhesive) in a dispersion medium (e.g., a slurry composition) have been proposed. Materials obtained by simultaneously using two binders have also been proposed. For example, Patent Document 1 describes a composite material comprising a solid electrolyte, active material, a non-polar solvent, a first binder insoluble in the non-polar solvent, and a second binder soluble in the non-polar solvent, wherein the first binder and the second binder have different SP values.

[0005] Previous technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2015-244428 Summary of the Invention

[0008] The technical problem to be solved by the invention

[0009] When forming the active material layer using solid particle materials (inorganic solid electrolytes, active materials, conductive additives, etc.), various properties are required for the active material layer forming material and the binder used therein, from the viewpoint of improving the battery performance of all-solid-state secondary batteries (e.g., reducing battery resistance, improving rate performance, or cycle performance). For example, the active material layer forming material requires excellent dispersion stability (both initial dispersion and dispersion stability are collectively referred to as dispersion characteristics) to maintain the good initial dispersibility of the freshly prepared solid particle material (also called solid particles). Furthermore, the active material layer formed by the active material layer forming material requires strong adhesion (close bonding) to firmly bind the solid particles. On the other hand, since the binder has poor ionic and electronic conductivity, from the viewpoint of suppressing the increase in battery resistance, it is required to reduce the binder content in the active material layer forming material and the active material layer.

[0010] As mentioned above, active material layer forming materials require both solid particle dispersion characteristics and strong adhesion while reducing the binder content, i.e., taking into account these two opposing characteristics.

[0011] The objective of this invention is to provide an electrode composition that achieves excellent dispersion characteristics and strong adhesion of solid particles while reducing the content of polymer binder. Furthermore, the objective of this invention is to provide an electrode sheet for an all-solid-state secondary battery using this electrode composition, an all-solid-state secondary battery, and a method for manufacturing the electrode composition, the electrode sheet for an all-solid-state secondary battery, and the all-solid-state secondary battery.

[0012] means for solving technical problems

[0013] In conventional active material forming materials, even with improvements such as changing the mixing order, the adhesive used to disperse and bind these solid particles as a whole is still assumed to be a homogeneous mixture containing inorganic solid electrolytes, active materials, etc.

[0014] However, the inventors conducted in-depth research on active material layer forming materials and found that, generally, when the interaction between the binder and the inorganic solid electrolyte increases, the interaction with the active material also increases. Therefore, they concluded that even if the solid particle group containing the inorganic solid electrolyte and the active material is assumed to be a single mixture, and research is conducted on the binder used simultaneously, it is insufficient to simultaneously consider the dispersion characteristics and adhesion of the solid particle group and the reduction of the binder content. Therefore, after further research, the inventors conceived of the following: in an active material layer forming material containing the active material, inorganic solid electrolyte, and dispersion medium, instead of assuming the solid particle group containing the inorganic solid electrolyte and the active material to be a single mixture, the inorganic solid electrolyte and the active material are assumed to be separate solid particle groups, and the binder for each solid particle group is improved. Based on this concept, the inventors discovered that by combining a binder that preferentially adsorbs onto the active material and a binder that preferentially adsorbs onto the inorganic solid electrolyte from a binder dissolved in a dispersion medium, the total binder content can be reduced. Simultaneously, the active material and inorganic solid electrolyte can be stably dispersed separately in the active material layer forming material not only immediately after preparation but also over time (with excellent dispersion characteristics), thus forming an active material layer that firmly bonds the active material and inorganic solid electrolyte. Furthermore, it was found that this active material layer forming material can achieve a low-resistance active material layer with firmly bonded solid particles, and the all-solid-state secondary battery assembled with this active material layer can achieve low resistance and excellent battery performance.

[0015] Based on these insights, the present invention underwent further and repeated research, thereby completing the present invention.

[0016] That is, the above-mentioned problems are solved through the following solutions.

[0017] <1> An electrode composition comprising an inorganic solid electrolyte having conductive ions of metals belonging to Group 1 or Group 2 of the periodic table, an active material, a polymer binder, and a dispersion medium, wherein,

[0018] The polymer adhesive contains:

[0019] Polymer binder A, dissolved in a dispersion medium, exhibits an adsorption rate of over 20% for active substances within the dispersion medium, which is greater than its adsorption rate for inorganic solid electrolytes; and

[0020] Polymer binder B, dissolved in a dispersion medium, exhibits an adsorption rate of over 20% for inorganic solid electrolytes in the dispersion medium, which is greater than its adsorption rate for active substances.

[0021] <2> The electrode composition according to <1> contains a conductive additive.

[0022] <3> The electrode composition according to <1> or <2>, wherein,

[0023] The polymer forming at least one of polymeric adhesive A and polymeric adhesive B comprises a constituent having functional groups selected from the following functional group (a).

[0024] <Functional Groups (a)>

[0025] Hydroxyl, amino, carboxyl, sulfonyl, phosphate, phosphonic acid, thioalkyl, ether, imino, amide, imide, carbamate, urea, heterocyclic, aryl, carboxylic anhydride.

[0026] <4> The electrode composition according to any one of <1> to <3>, wherein the polymer forming the polymer binder A has at least one type of bond selected from urethane bonds, urea bonds, amide bonds, imide bonds and ester bonds on its main chain.

[0027] <5> The electrode composition according to any one of <1> to <4>, wherein the polymer forming the polymer binder B is formed by polymerizing monomers having carbon-carbon unsaturated bonds.

[0028] <6> The electrode composition according to any one of <1> to <5>, wherein the content of polymer binder A is 1.5% by mass or less in 100% by mass of the solid components of the electrode composition.

[0029] The content of polymer binder B is less than 1.5% by mass in 100% by mass of the solid components of the electrode composition.

[0030] <7> An electrode sheet for an all-solid-state secondary battery, having an active material layer formed using any one of the electrode compositions described in <1> to <6> above.

[0031] <8> An all-solid-state secondary battery, which sequentially comprises a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer, wherein,

[0032] At least one of the positive electrode active material layer and the negative electrode active material layer is an active material layer formed using any one of the electrode compositions <1> to <6>.

[0033] <9> A method for manufacturing an electrode composition, which is a method for manufacturing the electrode composition described in any one of <1> to <6> above, comprising:

[0034] The process for preparing an active substance composition containing an active substance, a polymer binder A, and a dispersion medium;

[0035] The process for preparing a solid electrolyte composition containing an inorganic solid electrolyte, a polymer binder B, and a dispersion medium; and

[0036] The process of mixing the active substance composition and the solid electrolyte composition.

[0037] <10> A method for manufacturing an electrode sheet for an all-solid-state secondary battery, wherein the electrode composition described in any one of <1> to <6> is used to form a film.

[0038] <11> A method for manufacturing an all-solid-state secondary battery, wherein the all-solid-state secondary battery is manufactured by the manufacturing method described in <10> above.

[0039] Invention Effects

[0040] This invention provides an electrode composition that achieves excellent dispersion characteristics and strong adhesion of solid particles while reducing the content of the composition. Furthermore, this invention provides an electrode sheet for an all-solid-state secondary battery having an active material layer composed of this electrode composition, and an all-solid-state secondary battery. In addition, this invention provides methods for manufacturing the electrode composition, the electrode sheet for an all-solid-state secondary battery, and the all-solid-state secondary battery. Attached Figure Description

[0041] Figure 1 This is a schematic longitudinal sectional view of an all-solid-state secondary battery according to a preferred embodiment of the present invention. Detailed Implementation

[0042] In this invention, the numerical range indicated by "~" refers to the range encompassed by the values ​​recorded before and after "~" as lower and upper limits. Furthermore, in this invention, when multiple numerical ranges are defined for the content, physical properties, etc., of a component, the upper and lower limits forming the numerical range are not limited to specific combinations of upper and lower limits recorded before and after "~" as a specific numerical range; rather, they can be defined as numerical ranges formed by appropriately combining the upper and lower limits of each numerical range.

[0043] In this invention, the designation of a compound (e.g., when referred to as a compound by appending a compound at the end) means that in addition to the compound itself, it also includes its salt and its ions. Furthermore, it includes derivatives that modify a portion by introducing substituents or the like without impairing the effects of this invention.

[0044] In this invention, (meth)acrylic acid refers to one or both of acrylic acid and methacrylic acid. The same applies to (meth)acrylates.

[0045] In this invention, the term "substituent, linking group, etc." (hereinafter referred to as "substituent, etc.") refers to a group that may have a suitable substituent. Therefore, in this invention, even when simply described as a YYY group, the YYY group includes not only those without substituents but also those with substituents. This meaning is the same for compounds where substitution or unsubstituent is not explicitly stated. As a preferred substituent, substituent Z, described later, can be cited as an example.

[0046] In this invention, when multiple substituents, etc., are represented by specific symbols, or when multiple substituents are specified simultaneously, or when one of them is specified, it means that each substituent, etc., may be the same as or different from each other. Furthermore, even without specific explanation, when multiple substituents, etc., are adjacent, it means that they may be linked together or fused together to form a ring.

[0047] In this invention, polymer refers to aggregates, which is synonymous with the term high molecular weight compound. Furthermore, polymer adhesive (also simply called adhesive) refers to an adhesive composed of polymers, including the polymer itself and adhesives formed by containing polymers.

[0048] In this invention, a composition containing an inorganic solid electrolyte, an active material, and a dispersion medium, and used as a material for forming the active material layer of an all-solid-state secondary battery (active material layer forming material), is referred to as an electrode composition for an all-solid-state secondary battery, or simply as an electrode composition. On the other hand, a composition containing an inorganic solid electrolyte and used as a material for forming the solid electrolyte layer of an all-solid-state secondary battery is referred to as an inorganic solid electrolyte-containing composition, which typically does not contain an active material.

[0049] In this invention, the electrode composition comprises a positive electrode composition containing a positive electrode active material and a negative electrode composition containing a negative electrode active material. Therefore, sometimes either or both of the positive electrode composition and the negative electrode composition are simply referred to as an electrode composition, and sometimes either or both of the positive electrode active material layer and the negative electrode active material layer are simply referred to as an active material layer or an electrode active material layer. Furthermore, either or both of the positive electrode active material and the negative electrode active material are collectively referred to as an active material or an electrode active material.

[0050] [Electrode Composition]

[0051] The electrode composition of the present invention comprises an inorganic solid electrolyte (SE) having conductivity of ions belonging to Group 1 or Group 2 of the periodic table, an active material (AC), a polymer binder (PB), and a dispersion medium (D). The polymer binder (PB) comprises polymer binder A dissolved in the dispersion medium (D) and satisfying the following adsorption rate, and polymer binder B dissolved in the dispersion medium (D) and satisfying the following adsorption rate. The electrode composition may contain only one type of polymer binder A and polymer binder B, or it may contain two or more types.

[0052] Polymer binder A: The adsorption rate of active material (AC) in dispersion medium (D) is over 20%, which is greater than the adsorption rate of inorganic solid electrolyte (SE).

[0053] Polymer binder B: The adsorption rate of inorganic solid electrolyte (SE) in the dispersion medium (D) is greater than 20%, which is also greater than the adsorption rate of the active material (AC).

[0054] In the dispersion medium (D), the polymer binder (PB) for the inorganic solid electrolyte (SE) and active material (AC), combined with the electrode composition of the present invention containing polymer binder A and polymer binder B, ensures that even with a reduction in the total content of the binder polymers (especially the combined content of polymer binders A and B), the inorganic solid electrolyte (SE) and active material (AC) are stably dispersed (with excellent dispersion characteristics) not only immediately after preparation but also over time. Furthermore, during the film formation of the electrode composition, the inorganic solid electrolyte (SE) and active material (AC) are firmly bonded together. Therefore, by using this electrode composition as an active material layer forming material, a low-resistance active material layer with a firm bond between the inorganic solid electrolyte (SE) and active material (AC) can be achieved, and an all-solid-state secondary battery exhibiting low resistance and excellent battery characteristics can also be realized.

[0055] The detailed reasons are still unclear, but the following is believed.

[0056] The electrode composition of the present invention contains a polymer binder A that exhibits higher adsorption capacity (preferential adsorption) for an active material (AC) than for an inorganic solid electrolyte (SE), and a polymer binder B that exhibits higher adsorption capacity (preferential adsorption) for an inorganic solid electrolyte (SE) than for an active material (AC). In this electrode composition, the preferential adsorption amounts of polymer binders A and B for the active material (AC) or the inorganic solid electrolyte (SE) vary depending on the adsorption rate of each binder, the difference in adsorption rates, the content of each component, the type of dispersion medium (D), and further, the preparation method or conditions of the electrode composition, and therefore cannot be uniquely determined. However, it is presumed that polymer binder A, exhibiting the aforementioned adsorption rate, is mostly adsorbed onto the active material (AC), and polymer binder B is mostly adsorbed onto the inorganic solid electrolyte (SE). Therefore, polymer binder A can improve the dispersibility of the preferentially adsorbed active material (AC), and polymer binder B can improve the dispersibility of the preferentially adsorbed inorganic solid electrolyte (SE). Furthermore, it is believed that both polymer binders A and B dissolve in the dispersion medium (D) and their molecular chains unfold, causing the adsorbed active material (AC) or inorganic solid electrolyte (SE) to repel each other, thereby effectively suppressing (re)aggregation or precipitation (excellent dispersion characteristics). In addition, the adsorption and dispersion states of the polymer binders and the active material (AC) or inorganic solid electrolyte (SE) are maintained during the film formation process of the electrode composition. As a result, it is believed that in the active material layer of the formed film, the active material (AC) or inorganic solid electrolyte (SE) is firmly bonded while maintaining a highly dispersed state. Moreover, by using polymer binders A and B simultaneously, they can be adsorbed onto the active material (AC) and inorganic solid electrolyte (SE) respectively, and dispersed and bonded, thus reducing the amount of polymer binder required for dispersion and bonding of the active material (AC) and inorganic solid electrolyte (SE). Therefore, the obstruction of the polymer binder (PB) to the construction of ion conduction pathways and electron conduction pathways can be suppressed. Furthermore, while maintaining the aforementioned highly dispersed state, an active material layer can be formed, thus the inorganic solid electrolyte (SE) and active material (AC) are not easily unevenly distributed, and deviations in the contact state within the active material layer can be suppressed.

[0057] Thus, when forming the active material layer using an electrode composition that achieves excellent dispersion characteristics and strong adhesion of the inorganic solid electrolyte (SE) and active material (AC) while reducing the content of polymer binder, it is possible to suppress uneven distribution of the inorganic solid electrolyte (SE) and active material (AC) and ensure direct contact, while simultaneously forming an active material layer that firmly binds the inorganic solid electrolyte (SE) and active material (AC). Therefore, the all-solid-state secondary battery with this active material layer is considered to have excellent battery characteristics such as low resistance (indicating high ion conductivity and high electronic conductivity) and high rate performance.

[0058] It is believed that polymer binders A and B exhibit the following functions: in the electrode composition, in a state dissolved in the dispersion medium (D), they adsorb onto the active material (AC) or inorganic solid electrolyte (SE) or are situated between solid particles, dispersing the active material (AC) or inorganic solid electrolyte (SE) within the dispersion medium (D). On the other hand, it is believed that in the active material layer, polymer binders A and B function as binders that adsorb onto the active material (AC) or inorganic solid electrolyte (SE) and bond them together. Furthermore, polymer binders A and B preferentially adsorb onto the active material (AC) or inorganic solid electrolyte (SE), but may also adsorb onto the inorganic solid electrolyte (SE) or active material (AC).

[0059] Here, there are no particular limitations on the adsorption of active substances (AC) or inorganic solid electrolytes (SE) by polymer binders A and B, including not only physical adsorption but also chemical adsorption (adsorption through the formation of chemical bonds, adsorption through electron donation and acceptance, etc.).

[0060] Furthermore, polymer adhesives A and B also function as adhesives to bond current collectors and solid particles.

[0061] Thus, the electrode composition exhibits the aforementioned excellent properties, and is therefore preferably used as an electrode sheet for all-solid-state secondary batteries and as a forming material (constituent layer forming material) for the active material layer of all-solid-state secondary batteries. In particular, it is preferably used as a material for forming the positive electrode active material layer.

[0062] The electrode composition of the present invention is preferably a slurry formed by dispersing inorganic solid electrolyte and active material in a dispersion medium.

[0063] The electrode composition of the present invention is preferably a non-aqueous composition. In the present invention, the non-aqueous composition includes not only being free of water but also having a water content (also referred to as moisture content) preferably of 500 ppm or less. In the non-aqueous composition, the water content is more preferably 200 ppm or less, further preferably 100 ppm or less, and particularly preferably 50 ppm or less. If the electrode composition is a non-aqueous composition, the degradation of the inorganic solid electrolyte can be suppressed. Moisture content refers to the amount of water contained in the electrode composition (relative to the mass ratio of the electrode composition), specifically, it is defined as the value obtained by filtration using a 0.02 μm membrane filter and determination using Karl Fischer titration.

[0064] The components contained in the electrode composition of the present invention and the components that may be contained therein are described below.

[0065] <Inorganic Solid Electrolytes (SE)>

[0066] The electrode composition of the present invention contains an inorganic solid electrolyte (SE).

[0067] In this invention, inorganic solid electrolytes refer to inorganic solid electrolytes, which are solid electrolytes capable of allowing ions to move within them. Because they do not contain organic matter, which is the primary ion-conducting material, they are clearly distinguished from organic solid electrolytes (such as polymeric electrolytes represented by polyethylene oxide (PEO) and organic electrolyte salts represented by lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)). Furthermore, since inorganic solid electrolytes are solid in their stable state, they generally do not dissociate or ionize into cations and anions. In this respect, they are also clearly distinguished from inorganic electrolyte salts (such as LiPF6, LiBF4, lithium bis(fluorosulfonyl)imide (LiFSI), and LiCl) that dissociate or ionize into cations and anions in electrolytes or polymers. There are no particular limitations as long as the inorganic solid electrolyte possesses the conductivity of ions belonging to Group 1 or Group 2 of the periodic table; it generally does not possess electronic conductivity.

[0068] The inorganic solid electrolyte contained in the electrode composition of the present invention can be appropriately selected from solid electrolyte materials commonly used in all-solid-state secondary batteries. For example, as inorganic solid electrolytes, (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 can be mentioned. From the viewpoint of being able to form a better interface between the active material and the inorganic solid electrolyte, a sulfide-based inorganic solid electrolyte is preferred.

[0069] In the case of the all-solid-state secondary battery of the present invention being a lithium-ion battery, the inorganic solid electrolyte preferably has lithium-ion ionic conductivity.

[0070] (i) Sulfide-based inorganic solid electrolytes

[0071] Sulfide-based inorganic solid electrolytes are preferably compounds containing sulfur atoms, exhibiting conductivity of metal ions belonging to Group 1 or Group 2 of the periodic table, and possessing electronic insulation properties. Sulfide-based inorganic solid electrolytes are preferably compounds containing at least Li, S, and P as elements and possessing lithium-ion conductivity, but may also appropriately contain other elements besides Li, S, and P.

[0072] Examples of sulfide-based inorganic solid electrolytes include lithium-ion conductive inorganic solid electrolytes that satisfy the composition represented by the following formula (S1).

[0073] L a1 M b1 P c1 S d1 Ae1 (S1)

[0074] In formula (S1), L represents an element selected from Li, Na, and K, preferably Li. M represents an element selected from B, Zn, Sn, Si, Cu, Ga, Sb, Al, and Ge. A represents an element selected from I, Br, Cl, and F. a1 to e1 represent the composition ratio of each element, where a1:b1:c1:d1:e1 satisfies 1–12:0–5:1:2–12:0–10. a1 is preferably 1–9, more preferably 1.5–7.5. b1 is preferably 0–3, more preferably 0–1. d1 is preferably 2.5–10, more preferably 3.0–8.5. e1 is preferably 0–5, more preferably 0–3.

[0075] As described below, the composition ratio of each element can be controlled by adjusting the amount of raw material compounds used in the manufacture of sulfide-based inorganic solid electrolytes.

[0076] Sulfide-based inorganic solid electrolytes can be amorphous (glass), crystallized (glass-ceramic), or partially crystallized. For example, Li-PS-based glasses or Li-PS-based glass-ceramics containing Li, P, and S can be used.

[0077] Sulfide-based inorganic solid electrolytes can be manufactured by reacting at least two of the following raw materials: lithium sulfide (Li2S), phosphorus sulfide (e.g., phosphorus pentasulfide (P2S5)), monomeric phosphorus, monomeric sulfur, sodium sulfide, hydrogen sulfide, lithium halides (e.g., LiI, LiBr, LiCl), and sulfides of the element represented by M above (e.g., SiS2, SnS, GeS2).

[0078] The ratio of Li₂S to P₂S₅ in Li-PS-based glasses and Li-PS-based glass-ceramics, in terms of the molar ratio of Li₂S:P₂S₅, is preferably 60:40 to 90:10, more preferably 68:32 to 78:22. Setting the Li₂S to P₂S₅ ratio within this range improves lithium-ion conductivity. Specifically, the lithium-ion conductivity is preferably set to 1 × 10⁻⁶. -4 S / cm or higher, more preferably 1×10 -3 S / cm or higher. Although no specific upper limit is set, it is actually 1×10⁻⁶. -1 Below S / cm.

[0079] As specific examples of sulfide-based inorganic solid electrolytes, combinations of raw materials are illustrated below. Examples include Li₂S-P₂S₅, Li₂S-P₂S₅-LiCl, Li₂S-P₂S₅-H₂S, Li₂S-P₂S₅-H₂S-LiCl, Li₂S-LiI-P₂S₅, Li₂S-LiI-Li₂O-P₂S₅, Li₂S-LiBr-P₂S₅, Li₂S-Li₂O-P₂S₅, Li₂S-Li₃PO₄-P₂S₅, Li₂S-P₂S₅-P₂O₅, Li₂S-P₂S₅-SiS₂, Li₂S-P₂S₅-SiS₂-LiCl, Li₂S-P₂S₅-SnS, and Li₂S-P₂S₅-Al₂S₅. 3. Li2S-GeS2, Li2S-GeS2-ZnS, Li2S-Ga2S3, Li2S-GeS2-Ga2S3, Li2S-GeS2-P2S5, Li2S-GeS2-Sb2S5, Li2S-GeS2-Al2S3, Li2S-SiS2, L i2S-Al2S3, Li2S-SiS2-Al2S3, Li2S-SiS2-P2S5, Li2S-SiS2-P2S5-LiI, Li2S-SiS2-LiI, Li2S-SiS2-Li4SiO4, Li2S-SiS2-Li3PO4, Li 10 GeP2S 12 And so on. The mixing ratio of each raw material is not limited. As a method for synthesizing sulfide-based inorganic solid electrolyte materials using this raw material composition, for example, the amorphization method can be cited. Examples of amorphization methods include mechanical polishing, solution processing, and melt quenching. The process can be carried out at room temperature, thereby simplifying the manufacturing process.

[0080] (ii) Oxide-based inorganic solid electrolytes

[0081] Oxide-based inorganic solid electrolytes are preferably compounds containing oxygen atoms, possessing conductivity of ions belonging to Group 1 or Group 2 of the periodic table, and having electronic insulation properties.

[0082] For oxide-based inorganic solid electrolytes, the preferred ionic conductivity is 1×10⁻⁶. -6 S / cm or higher, preferably 5×10 -6 S / cm or higher, especially preferably 1×10 -5 S / cm or higher. Although there is no specific upper limit, it is actually 1×10 -1 Below S / cm.

[0083] As a specific example of a compound, Li can be cited. xa La yaTiO3 [xa satisfies 0.3≤xa≤0.7, ya satisfies 0.3≤ya≤0.7.] (LLT); Li xb La yb Zr zb M bb mb O nb (M bb It consists of one or more elements selected from Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In, and Sn. xb satisfies 5 ≤ ​​xb ≤ 10, yb satisfies 1 ≤ yb ≤ 4, zb satisfies 1 ≤ zb ≤ 4, mb satisfies 0 ≤ mb ≤ 2, and nb satisfies 5 ≤ ​​nb ≤ 20. Li xc B yc M cc zc O nc (M cc It is an element 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, nd satisfies 3≤nd≤13.) ; Li (3-2xe) M ee xe D ee O(xe) represents a number greater than 0 and less than 0.1, M ee This represents a divalent metal atom. (D) ee This represents a halogen atom or a combination of two or more halogen atoms. (Li) xf Si yf O zf (xf satisfies 1 ≤ xf ≤ 5, yf satisfies 0 < yf ≤ 3, zf satisfies 1 ≤ zf ≤ 10.) ; Li xg S yg O zg (xg satisfies 1≤xg≤3, yg satisfies 0<yg≤2, zg satisfies 1≤zg≤10.) ; Li3BO3; Li3BO3-Li2SO4; Li2O-B2O3-P2O5; Li2O-SiO2; Li6BaLa2Ta2O 12 Li3PO (4-3 / 2w) N w(w satisfies w < 1); Li has a LISICON (Lithium super ionic conductor) type crystal structure. 3.5 Zn 0.25 GeO4; La with a perovskite-type crystal structure 0.55 Li 0.35 TiO3; LiTi2P3O with a NASICON (Natrium superionic conductor) type crystal structure 12 Li 1+xh+yh (Al, Ga) xh (Ti, Ge) 2-xh Si yh P 3-yh O 12 (xh satisfies 0 ≤ xh ≤ 1, yh satisfies 0 ≤ yh ≤ 1.) ; Li7La3Zr2O with garnet-type crystal structure 12 (LLZ) etc.

[0084] Furthermore, phosphorus compounds containing Li, P, and O are preferred. Examples include lithium phosphate (Li3PO4); LiPON, in which nitrogen element replaces part of the oxygen element in lithium phosphate; and LiPOD. 1 (D 1 Preferably, it contains one or more elements selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Ag, Ta, W, Pt, and Au.

[0085] Furthermore, LiA can be preferably used. 1 ON(A 1 It consists of one or more elements selected from Si, B, Ge, Al, C, and Ga.

[0086] (iii) Halogen-based inorganic solid electrolytes

[0087] Halogen-based inorganic solid electrolytes are preferably compounds containing halogen atoms, possessing conductivity of ions belonging to Group 1 or Group 2 of the periodic table, and having electronic insulation properties.

[0088] There are no particular limitations on the type of inorganic solid electrolyte, such as LiCl, LiBr, LiI, and compounds like Li3YBr6 and Li3YCl6 described in ADVANCED MATERIALS, 2018, 30, 1803075. Among these, Li3YBr6 and Li3YCl6 are preferred.

[0089] (iv) Hydride-based inorganic solid electrolytes

[0090] Hydride-based inorganic solid electrolytes are preferably compounds containing hydrogen atoms, possessing conductivity of ions belonging to Group 1 or Group 2 of the periodic table, and having electronic insulation properties.

[0091] As a hydride-based inorganic solid electrolyte, there are no particular limitations; examples include LiBH4, Li4(BH4)3I, and 3LiBH4-LiCl.

[0092] The inorganic solid electrolyte contained in the electrode composition of the present invention is preferably in particulate form. The shape of the particles is not particularly limited and can be flat, amorphous, etc., but is preferably spherical or granular.

[0093] When the inorganic solid electrolyte is in particulate form, there is no particular limitation on the particle size (volume average particle size) of the inorganic solid electrolyte, but it is preferably 0.01 μm or more, more preferably 0.1 μm or more, and even more preferably 0.5 μm or more. As an upper limit, it is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 10 μm or less.

[0094] The particle size of the inorganic solid electrolyte was determined in the following order: A 1% (w / w) dispersion of the inorganic solid electrolyte particles was prepared by diluting the particles in a 20 mL sample vial with water (or heptane in the case of substances unstable in water). The diluted dispersion sample was irradiated with ultrasound at 1 kHz for 10 minutes and then immediately used in the test. Using this dispersion sample, 50 data acquisitions were performed using a laser diffraction / scattering particle size distribution measuring device LA-920 (trade name, manufactured by HORIBA, Ltd.) at 25°C using a measuring quartz cell to obtain the volume average particle size. Other detailed conditions were referenced as needed in Japanese Industrial Standard (JIS) Z8828:2013 "Particle Size Analysis - Dynamic Light Scattering Method". Five samples were prepared for each grade, and their average value was used.

[0095] There are no particular limitations on the method for adjusting the particle size; well-known methods can be used, such as the use of conventional pulverizers or classifiers. For example, suitable pulverizers or classifiers include mortars, ball mills, sand mills, vibratory ball mills, satellite ball mills, planetary ball mills, rotary airflow mills, and sieves. During pulverization, wet pulverization with a dispersion medium such as water or methanol can be appropriately performed. To achieve the desired particle size, classification is preferred. Classification is not particularly limited; sieves, air classifiers, etc., can be used. Both dry and wet classification methods can be used.

[0096] The electrode composition may contain one or more inorganic solid electrolytes.

[0097] The content of inorganic solid electrolyte (SE) in the electrode composition is not particularly limited and can be appropriately determined. For example, from the viewpoint of dispersion characteristics and adhesion, it is preferable to have 50% or more of the solid component, including the active material (AC), out of 100% by mass; more preferably 70% or more by mass; and especially preferably 90% or more by mass. As an upper limit, from the same viewpoint, it is preferable to have 99.9% or less by mass; more preferably 99.5% or less by mass; and especially preferably 99% or less by mass.

[0098] In this invention, solid components refer to those components that do not volatilize or evaporate and disappear after the electrode composition has been dried at 150°C for 6 hours under a nitrogen atmosphere and at a pressure of 1 mmHg. Typically, this refers to components other than the dispersion medium (D) described later. Furthermore, the content in the total solid components refers to the content in 100% by mass of the total mass of the solid components.

[0099] The ratio of the content of inorganic solid electrolyte (SE) to the content of the active material described later in 100% by mass of the solid component of the electrode composition is not particularly limited, but is preferably 1:1 to 1:6, and more preferably 1:1.2 to 1:5.

[0100] <Active Substances (AC)>

[0101] The electrode composition of the present invention contains an active substance (AC) capable of intercalating and deintercalating ions of metals belonging to Group 1 or Group 2 of the periodic table.

[0102] As active materials (AC), examples of positive electrode active materials and negative electrode active materials can be cited below.

[0103] (Positive electrode active material)

[0104] The positive electrode active material is an active material capable of intercalating and deintercalating ions of metals belonging to Group 1 or Group 2 of the periodic table, preferably an active material capable of reversibly intercalating and deintercalating lithium ions. There are no particular limitations as long as the material has the above-mentioned properties, and it can be a transition metal oxide from a decomposition battery or an element that can recombine with Li, such as sulfur.

[0105] Among them, transition metal oxides are preferred as positive electrode active materials, and more preferably materials containing the transition metal element M. a A transition metal oxide (selected from one or more elements including Co, Ni, Fe, Mn, Cu, and V). Furthermore, element M can be mixed into this transition metal oxide. b(Elements from Group 1(Ia) and Group 2(IIa) of the periodic table, excluding lithium, and elements such as Al, Ga, In, Ge, Sn, Pb, Sb, Bi, Si, P, and B). As a mixing amount, it is preferable to be relative to the transition metal element M. a The amount (100 mol%) is 0-30 mol%. More preferably, it is Li / M a The mixtures are synthesized by mixing in a molar ratio of 0.3 to 2.2.

[0106] Specific examples of transition metal oxides include (MA) transition metal oxides with a layered rock salt structure, (MB) transition metal oxides with a spinel structure, (MC) lithium-containing transition metal phosphate compounds, (MD) lithium-containing transition metal halophosphate compounds, and (ME) lithium-containing transition metal silicate compounds.

[0107] Specific examples of transition metal oxides (MA) with layered rock salt-type structures include LiCoO2 (lithium cobalt oxide [LCO]), LiNi2O2 (lithium nickel oxide), and LiNi 0.85 Co 0.10 Al 0.05 O2 (lithium nickel cobalt aluminum oxide [NCA]), LiNi 1 / 3 Co 1 / 3 Mn 1 / 3O2 (lithium nickel manganese cobalt oxide [NMC]) and LiNi 0.5 Mn 0.5 O2 (lithium manganese nickel oxide).

[0108] Specific examples of transition metal oxides (MB) with spinel-type structures include LiMn2O4 (LMO), LiCoMnO4, Li2FeMn3O8, Li2CuMn3O8, Li2CrMn3O8, and Li2NiMn3O8.

[0109] Examples of lithium-containing transition metal phosphate compounds include olivine-type iron phosphates such as LiFePO4 and Li3Fe2(PO4)3, iron pyrophosphates such as LiFeP2O7, cobalt phosphates such as LiCoPO4, and monoclinic NASICON-type vanadium phosphates such as Li3V2(PO4)3 (lithium vanadium phosphate).

[0110] Examples of lithium-containing transition metal halophosphates (MD) include iron fluorophosphates such as Li2FePO4F, manganese fluorophosphates such as Li2MnPO4F, and cobalt fluorophosphates such as Li2CoPO4F.

[0111] Examples of lithium-containing transition metal silicate compounds include Li2FeSiO4, Li2MnSiO4, and Li2CoSiO4.

[0112] In this invention, (MA) is preferably a transition metal oxide having a layered rock salt structure, and more preferably LCO or NMC.

[0113] The positive electrode active material contained in the electrode composition of the present invention is preferably in particulate form. The shape of the particles is not particularly limited and can be flat, amorphous, etc., but is preferably spherical or granular.

[0114] When the positive electrode active material is in particulate form, there is no particular limitation on the particle size (volume average particle size) of the positive electrode active material. For example, it is preferably 0.1 to 50 μm, and more preferably 0.5 to 10 μm. The particle size of the positive electrode active material can be adjusted in the same way as the particle size of the inorganic solid electrolyte, and its measurement method can also be the same as that of the inorganic solid electrolyte.

[0115] Positive active materials obtained by sintering can also be used after being cleaned with water, acidic aqueous solutions, alkaline aqueous solutions, and organic solvents.

[0116] The electrode composition of the present invention may contain one or more positive active substances.

[0117] The content of the positive electrode active material in the electrode composition is not particularly limited and can be appropriately determined. For example, in 100% by mass of the solid content, it is preferably 10 to 97% by mass, more preferably 30 to 95% by mass, even more preferably 40 to 93% by mass, and particularly preferably 50 to 90% by mass.

[0118] (Negative electrode active material)

[0119] The negative electrode active material is an active material capable of intercalating and deintercalating ions of metals belonging to Group 1 or Group 2 of the periodic table, preferably an active material capable of reversibly intercalating and deintercalating lithium ions. There are no particular limitations on the material as long as it possesses the aforementioned properties; examples include carbonaceous materials, metal oxides, metal composite oxides, lithium monomers, lithium alloys, and negative electrode active materials capable of forming alloys with lithium (capable of alloying). From a reliability perspective, carbonaceous materials, metal composite oxides, or lithium monomers are preferred. From the viewpoint of enabling high-capacity all-solid-state secondary batteries, active materials capable of alloying with lithium are preferred.

[0120] Carbonaceous materials used as negative electrode active materials refer to materials that are essentially composed of carbon. Examples include carbonaceous materials produced by sintering petroleum asphalt, carbon black such as acetylene black (AB), graphite (natural graphite, vapor-grown graphite, and other artificial graphite), and various synthetic resins such as PAN (polyacrylonitrile) resins or furfuryl alcohol resins. Furthermore, examples include various types of 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 planar graphite.

[0121] These carbonaceous materials are classified into non-graphitized carbonaceous materials (also known as hard carbon) and graphite-based carbonaceous materials according to the degree of graphitization. Furthermore, the carbonaceous materials preferably possess the facet spacing or density and crystallite size described in Japanese Patent Application Publication Nos. 62-22066, 2-6856, and 3-45473. The carbonaceous material need not be a single material; mixtures of natural and artificial graphite as described in Japanese Patent Application Publication No. 5-90844, and coated graphite as described in Japanese Patent Application Publication No. 6-4516, etc., can also be used.

[0122] As a carbonaceous material, hard carbon or graphite is preferred, and graphite is more preferred.

[0123] As for oxides of metals or half-metals suitable for use as negative electrode active materials, there are no particular limitations as long as they are oxides capable of absorbing and releasing lithium. Examples include oxides of metal elements (metal oxides), composite oxides of metal elements, or composite oxides of metal elements and half-metal elements (collectively referred to as metal composite oxides), and oxides of half-metal elements (half-metal oxides). Among these oxides, amorphous oxides are preferred, and further preferred are chalcogenides, the reaction products of metal elements with elements of Group 16 of the periodic table. In this invention, a half-metal element refers to an element exhibiting intermediate properties between a metal element and a non-half-metal element, typically including six elements: boron, silicon, germanium, arsenic, antimony, and tellurium, and further including three elements: selenium, polonium, and astatine. Furthermore, amorphous means having a broad scattering band with a vertex in the region of 20° to 40° at 2θ value in X-ray diffraction using CuKα rays, and may also have crystalline diffraction lines. The strongest intensity of the crystalline diffraction lines appearing in the region of 40° to 70° at a 2θ value is preferably 100 times or less than the intensity of the diffraction line at the apex of the broad scattering band appearing in the region of 20° to 40° at a 2θ value, more preferably 5 times or less, and especially preferably a non-crystalline diffraction line.

[0124] Among the compounds comprising the aforementioned amorphous oxides and chalcogenides, amorphous oxides of half-metallic elements or the aforementioned chalcogenides are more preferred, and (composite) oxides or chalcogenides comprising one or more elements selected from groups 13(IIIB) to 15(VB) of the periodic table (e.g., Al, Ga, Si, Sn, Ge, Pb, Sb, and Bi) are particularly preferred. Specific examples of preferred amorphous oxides and chalcogenides include, for example, Ga₂O₃, GeO, PbO, PbO₂, Pb₂O₃, Pb₂O₄, Pb₃O₄, Sb₂O₄, Sb₂O₈Bi₂O₃, Sb₂O₈Si₂O₃, Sb₂O₅, Bi₂O₃, Bi₂O₄, GeS, PbS, PbS₂, Sb₂S₃, or Sb₂S₅.

[0125] As a negative electrode active material that can be used with amorphous oxides centered on Sn, Si, and Ge, carbonaceous materials, lithium monomers, lithium alloys, and negative electrode active materials that can be alloyed with lithium are preferred examples.

[0126] From the viewpoint of high current density charge and discharge characteristics, oxides of metals or half-metals, especially metal (composite) oxides and the aforementioned chalcogenides, preferably contain at least one of titanium and lithium as constituent components. Examples of lithium-containing metal composite oxides (lithium composite metal oxides) include composite oxides of lithium oxide with the aforementioned metal (composite) oxides or chalcogenides; more specifically, Li₂SnO₂ can be cited.

[0127] The negative electrode active material, such as a metal oxide, preferably contains titanium (titanium oxide). Specifically, due to Li4Ti5O 12 Lithium titanate (LTO) exhibits minimal volume change during lithium ion adsorption and deintercalation, resulting in excellent rapid charge and discharge characteristics. This makes it a preferred choice for suppressing electrode degradation and improving the lifespan of lithium-ion secondary batteries.

[0128] There are no particular restrictions on lithium alloys used as negative electrode active materials, as long as they are alloys commonly used as negative electrode active materials in secondary batteries. For example, lithium-aluminum alloys can be cited. Specifically, lithium-aluminum alloys can be cited, which are made by adding 10% by mass of aluminum to lithium as the base metal.

[0129] There are no particular limitations on the negative electrode active material that can form an alloy with lithium, as long as it is a negative electrode active material commonly used in secondary batteries. Although such an active material experiences large expansion and contraction due to charging and discharging in all-solid-state secondary batteries, which accelerates the decline in cycle characteristics, the electrode composition of the present invention contains polymer binders A and B, which will be described later, thus suppressing the decline in cycle characteristics. Examples of such active materials include (negative electrode) active materials (alloys, etc.) containing silicon or tin, metals such as Al and In, and preferably negative electrode active materials containing silicon (silicon-containing active materials) that can achieve higher battery capacity. More preferably, silicon-containing active materials have a silicon content of 50 mol% or more of all constituent elements.

[0130] Generally, negative electrodes containing these 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 compared to carbon negative electrodes (graphite and acetylene black, etc.). That is, the amount of Li ions retained per unit mass increases. Therefore, the battery capacity (energy density) can be increased. Consequently, it has the advantage of extending battery operating time.

[0131] Examples of silicon-containing active materials include Si and SiO. x Silicon materials such as (0 < x ≤ 1), and silicon-containing alloys (e.g., LaSi2, VSi2, La-Si, Gd-Si, Ni-Si) or structured active materials (e.g., LaSi2 / Si) containing titanium, vanadium, chromium, manganese, nickel, copper, lanthanum, etc., and active materials containing silicon and tin elements such as SnSiO3 and SnSiS3, etc. Additionally, SiO... x It can be used as a negative electrode active material (semi-metal oxide), and Si is generated through the operation of an all-solid-state secondary battery, so it can be used as a negative electrode active material (its precursor material) that can be alloyed with lithium.

[0132] Examples of anode active materials containing tin include those containing Sn, SnO, SnO2, SnS, SnS2, and the aforementioned silicon and tin elements. Furthermore, composite oxides with lithium oxide, such as Li2SnO2, can also be cited.

[0133] In this invention, the above-mentioned negative electrode active material can be used without particular limitations. However, from the viewpoint of battery capacity, the negative electrode active material is preferably one that can be alloyed with lithium. More preferably, it is the above-mentioned silicon material or silicon-containing alloy (an alloy containing silicon element). It is even more preferably one that contains silicon (Si) or a silicon-containing alloy.

[0134] The negative electrode active material contained in the electrode composition of the present invention is preferably in particulate form. The shape of the particles is not particularly limited and can be flat, amorphous, etc., but is preferably spherical or granular.

[0135] When the negative electrode active material is in particulate form, there is no particular limitation on the particle size (volume average particle size) of the negative electrode active material. For example, it is preferably 0.1 to 60 μm, and more preferably 0.5 to 10 μm. The particle size of the negative electrode active material can be adjusted in the same way as the particle size of the inorganic solid electrolyte, and its measurement method can also be the same as that of the inorganic solid electrolyte.

[0136] The electrode composition of the present invention may contain one or more negative electrode active substances.

[0137] The content of the negative electrode active material in the electrode composition is not particularly limited and can be appropriately determined. For example, in 100% by mass of the solid content, it is preferably 10 to 90% by mass, more preferably 20 to 85% by mass, even more preferably 30 to 80% by mass, and even more preferably 40 to 75% by mass.

[0138] In this invention, a negative electrode active material layer can also be formed by charging a secondary battery. In this case, instead of the aforementioned negative electrode active material, ions of metals belonging to Group I or Group II of the periodic table generated within an all-solid-state secondary battery can be used. By bonding these ions with electrons and depositing them as metal, a negative electrode active material layer can be formed.

[0139] As a determination method, inductively coupled plasma (ICP) emission spectroscopy can be used. As a simple method, the chemical formula of the compound obtained by the above-mentioned firing method can be calculated based on the mass difference of the powder before and after firing.

[0140] (Coating of active substances)

[0141] The surfaces of the positive and negative electrode active materials can also be coated with different metal oxides. Examples of surface coating agents include metal oxides containing Ti, Nb, Ta, W, Zr, Al, Si, or Li. Specifically, examples include spinel titanate, tantalum oxides, niobium oxides, and lithium niobate compounds; for instance, Li₄Ti₅O₅ can be used. 12 , Li2Ti2O5, LiTaO3, LiNbO3, LiAlO2, Li2ZrO3, Li2WO4, Li2TiO3, Li2B4O7, Li3PO4, Li2MoO4, Li3BO3, LiBO2, Li2CO3, Li2SiO3, SiO2, TiO2, ZrO2, Al2O3, B2O3, etc.

[0142] Furthermore, the electrode surface containing positive or negative active materials can be surface-treated with sulfur or phosphorus.

[0143] Furthermore, the particle surfaces of the positive or negative active materials can be surface-treated by photochemical rays or active gases (such as plasma) before and after the aforementioned surface coating.

[0144] <Polymer Adhesives (PB)>

[0145] The electrode composition of the present invention contains a polymer binder (PB) containing one or more of the following polymer binders A, and one or more of the following polymer binders B.

[0146] Polymer binder A: Dissolves in dispersion medium (D) and has an adsorption rate of more than 20% for the active substance (AC) in dispersion medium (D), which is greater than the adsorption rate for inorganic solid electrolyte (SE). (Hereinafter, polymer binder A is sometimes referred to as binder for AC adsorption.)

[0147] Polymer binder B: Dissolved in dispersion medium (D), it has an adsorption rate of more than 20% for inorganic solid electrolytes (SE) in dispersion medium (D), which is greater than its adsorption rate for active substances (AC). (Hereinafter, polymer binder B is sometimes referred to as binder for SE adsorption.)

[0148] (Polymer Adhesive A)

[0149] Polymer binder A exhibits the characteristic of being soluble in the dispersion medium (D) contained in the electrode composition (solubility). Polymer binders dissolved in the dispersion medium are called soluble binders. While the amount of polymer binder A in the electrode composition depends on its content, solubility (described later), and the content of the dispersion medium (D), it generally exists in the electrode composition in a state dissolved in the dispersion medium (D). Thus, polymer binder A stably functions to disperse the active material (AC) in the dispersion medium (D).

[0150] In this invention, the polymer binder (PB) being soluble in the dispersion medium (D) means that its solubility in the dispersion medium (D) is 10% by mass or more in a solubility test. On the other hand, the polymer binder being insoluble in the dispersion medium (insoluble) means that its solubility in the dispersion medium (D) is less than 10% by mass in a solubility test. The method for determining solubility is as follows.

[0151] Weigh a specified amount of the polymer binder (PB) to be tested into a glass bottle, and add 100 g of the same dispersion medium (D) as that contained in the electrode composition. Stir the mixture at 80 rpm for 24 hours at 25°C on a mixing rotor. Determine the transmittance of the mixture obtained after 24 hours of stirring under the following conditions: Perform this test (transmittance determination) by varying the amount of polymer binder (PB) dissolved (the specified amount mentioned above), and define the upper limit concentration X (mass%) at which the transmittance becomes 99.8% as the solubility of the polymer binder (PB) in the dispersion medium mentioned above.

[0152] <Transmittance Measurement Conditions>

[0153] Dynamic light scattering (DLS) measurement

[0154] Apparatus: DLS-8000 DLS measuring device manufactured by Otsuka Electronics Co., Ltd.

[0155] Laser wavelength and output: 488nm / 100mW

[0156] Sample cell: NMR tube

[0157] The adsorption rate A of polymer binder A on active substance (AC) in dispersion medium (D) AC The adsorption rate is above 20% and is comparable to that of inorganic solid electrolytes (SE). SE Larger. Therefore, polymer binder A can preferentially adsorb onto the active substance (AC) more than inorganic solid electrolyte (SE), thereby improving the dispersion characteristics and adhesion of the active substance (AC) and reducing its content.

[0158] Adsorption rate A of polymer adhesive A AC A content of 20% or higher is acceptable, but considering the content, dispersion stability, and adhesion of the polymer binder, 30% or higher is preferred, 40% or higher is more preferred, and 60% or higher is even more preferred. Adsorption rate A AC There is no particular upper limit to the value; generally, as the adsorption rate A increases... AC Increase, adsorption rate A SE This also increases, which can sometimes hinder the preferential adsorption of the active substance (AC). Therefore, as an upper limit, it can be set to 95% or less, preferably 90% or less, more preferably 80% or less, and can also be set to 60%.

[0159] Adsorption rate A of polymer adhesive A SE As long as it is less than the above adsorption rate A AC There are no particular restrictions; the adsorption rate A can be used as a reference. AC The value of A is appropriately determined. This serves as the adsorption rate A.SE For example, it is preferably 45% or less, more preferably 35% or less, further preferably 20% or less, especially preferably 15% or less, and most preferably 10% or less.

[0160] In polymer adhesive A, the adsorption rate A AC With adsorption rate A SE The difference (A) AC -A SE There are no particular limitations, but it is preferable to exceed 0%, more preferably 5% or more, and even more preferably 10% or more. There are no particular limitations on the upper limit, for example, it can be set to 30%.

[0161] In this invention, the adsorption rate (%) of the polymer binder (PB), i.e., polymer binder A or B, is a value measured using the active substance (AC) or inorganic solid electrolyte (SE) contained in the electrode composition and a specific dispersion medium (D). It is an indicator of the degree of adsorption of the active substance (AC) or inorganic solid electrolyte (SE) by the polymer binder (PB) in the dispersion medium (D). Here, the adsorption of the active substance (AC) or inorganic solid electrolyte (SE) by the polymer binder (PB), as described above, includes not only physical adsorption but also chemical adsorption.

[0162] When the electrode composition contains multiple active substances (AC) or inorganic solid electrolytes (SE), the adsorption rate is defined as the adsorption rate of active substances (AC) or inorganic solid electrolytes (SE) having the same composition (type and content) as the active substances or inorganic solid electrolytes in the electrode composition. Similarly, when the electrode composition contains multiple specific dispersion media (D), the adsorption rate is determined using dispersion media (D) having the same composition (type and content) as the specific dispersion media in the electrode composition.

[0163] When the electrode composition contains multiple polymer binders A or B, the above-mentioned adsorption rate is measured for each polymer binder.

[0164] The adsorption rate A of polymer binder (PB) for active substance (AC) AC (%) The active material (AC), polymer binder (PB), and dispersion medium (D) used to prepare the electrode composition were measured as follows.

[0165] Specifically, 1.6 g of active substance (AC) and 0.08 g of polymer binder (PB) were placed in a 15 mL vial. While stirring with a mixing rotor, 8 g of dispersion medium (D) was added. The mixture was then stirred at 80 rpm for 30 minutes at room temperature (25°C). The resulting dispersion was filtered through a 1 μm filter. 2 g of the 8 g filtrate was collected and dried. The mass of the dried polymer binder (PB) (the mass of polymer binder (PB) not adsorbed onto the active substance (AC)) was measured.

[0166] Based on the mass BY of the polymer binder (PB) thus obtained and the mass of the polymer binder (PB) used being 0.08 g, the adsorption rate A of the polymer binder (PB) for the active substance (AC) is calculated using the following formula. AC (%). The average adsorption rate (%) obtained from performing this measurement twice is set as the adsorption rate A of the polymer binder (PB). AC (%).

[0167] Adsorption rate A AC (%) = [(0.08 - BY × 8 / 2) / 0.08] × 100

[0168] The adsorption rate A of polymer binder (PB) for inorganic solid electrolyte (SE) SE (%) The determination was performed using the inorganic solid electrolyte (SE), polymer binder (PB), and dispersion medium (D) used to prepare the electrode composition, as follows.

[0169] Specifically, 0.5 g of inorganic solid electrolyte (SE) and 0.26 g of polymer binder (PB) were placed in a 15 mL vial. While stirring with a mixing rotor, 25 g of dispersion medium (D) was added, and the mixture was further stirred at 80 rpm for 30 minutes at room temperature. The resulting dispersion was filtered through a 1 μm filter, and 2 g of the 25 g filtrate was collected and dried. The mass of the dried polymer binder (PB) (the mass of polymer binder (PB) not adsorbed onto the inorganic solid electrolyte (SE)) BX was measured.

[0170] Based on the mass BX of the polymer binder (PB) thus obtained and the mass of the polymer binder (PB) used (0.26 g), the adsorption rate A of the polymer binder (PB) for the inorganic solid electrolyte (SE) is calculated using the following formula. SE (%). The average adsorption rate (%) obtained from performing this measurement twice is set as the adsorption rate A of the polymer binder (PB). SE (%).

[0171] Adsorption rate A SE(%) = [(0.26 - BX × 25 / 2) / 0.26] × 100

[0172] In this invention, the two adsorption rates of the polymer adhesive A can be appropriately set by the type of polymer forming the polymer adhesive A (the structure and composition of the polymer chain), the type or content of the functional groups possessed by the polymer, etc.

[0173] In addition, other properties of polymer adhesive A will be described later.

[0174] (Polymer Adhesive B)

[0175] The polymer binder B exhibits properties that dissolve in the dispersion medium (D) contained in the electrode composition. While the amount of polymer binder B in the electrode composition depends on its content, solubility (described later), and the content of the dispersion medium (D), it generally exists in the electrode composition dissolved in the dispersion medium (D). Thus, the polymer binder B stably functions to disperse the inorganic solid electrolyte (SE) in the dispersion medium (D).

[0176] The adsorption rate A of polymer binder B on inorganic solid electrolyte (SE) in dispersion medium (D) SE The adsorption rate of the active substance (AC) is above 20% and is comparable to that of the adsorption rate of A. AC Larger. Therefore, polymer binder B can preferentially adsorb onto inorganic solid electrolyte (SE) than active material (AC), thereby improving the dispersion characteristics and adhesion of inorganic solid electrolyte (SE) and reducing its content.

[0177] Adsorption rate A of polymer adhesive B SE A content of 20% or higher is acceptable, but considering the content, dispersion stability, and adhesion of the polymer binder, 30% or higher is preferred, 40% or higher is more preferred, and 60% or higher is even more preferred. Adsorption rate A SE There is no particular upper limit to the value; generally, as the adsorption rate A increases... SE Increase, adsorption rate A AC This also increases, which can sometimes hinder the preferential adsorption of inorganic solid electrolytes (SE). Therefore, as an upper limit, it can be set to 95% or less, preferably 90% or less, more preferably 80% or less, and can also be set to 60%.

[0178] Adsorption rate A of polymer adhesive B AC As long as it is less than the above adsorption rate A SE There are no particular restrictions; the adsorption rate A can be used as a reference. SE The value of A is appropriately determined. This serves as the adsorption rate A. ACFor example, it is preferably 35% or less, more preferably 20% or less, even more preferably 15% or less, and especially preferably 10% or less.

[0179] In polymer adhesive B, the adsorption rate A SE With adsorption rate A AC The difference (A) SE -A AC There are no particular limitations, but it is preferable to exceed 0%, more preferably 5% or more, and even more preferably 10% or more. There are no particular limitations on the upper limit, for example, it can be set to 35%.

[0180] Adsorption rate A of polymer adhesive B SE and A AC The value is calculated using the measurement method described above.

[0181] In the combination of polymer adhesive A and polymer adhesive B, the adsorption rate A SE Or A AC The difference is not specifically limited, but from the viewpoint of being able to selectively adsorb onto the active substance (AC) more, the adsorption rates A of polymer binder A and polymer binder B are... AC The difference (absolute value) is preferably 5% or more, more preferably 10% or more, further preferably 15% or more, and even more preferably 30% or more. Similarly, from the viewpoint of being able to selectively adsorb onto inorganic solid electrolytes (SE), the adsorption rates A of polymer binder A and polymer binder B are... SE The difference (absolute value) is preferably 5% or more, more preferably 10% or more, and even more preferably 15% or more. Adsorption rate A AC The difference (absolute value) and adsorption rate A SE There is no particular upper limit to the difference (absolute value), which can be appropriately determined. As the adsorption rate A... AC The difference (absolute value) is preferably 60% or less, more preferably 50% or less. On the other hand, as the adsorption rate A... SE The difference (absolute value) is preferably 30% or less, more preferably 20% or less, and even more preferably 10% or less.

[0182] In this invention, the two adsorption rates of the polymer adhesive B can be appropriately set by the type of polymer forming the polymer adhesive B (the structure and composition of the polymer chain), the type or content of the functional groups possessed by the polymer, etc.

[0183] In addition, other properties of polymer adhesive B will be described later.

[0184] -The polymers that form polymer adhesives A and B-

[0185] There are no particular limitations on the polymers forming polymer binders A or B, as long as they impart solubility to the dispersion medium (D) and satisfy the aforementioned adsorption rates for the active substance (AC) or inorganic solid electrolyte (SE). Various polymers can be used. Among these, polymers having a polymeric chain with at least one type of bond selected from urethane bonds, urea bonds, amide bonds, imide bonds, and ester bonds, or a carbon-carbon double bond in the main chain are preferred. In this invention, a carbon-carbon double bond polymeric chain refers to a polymeric chain formed by the polymerization of carbon-carbon double bonds (olefinic unsaturated groups), specifically, a polymeric chain formed by the polymerization (homogeneous polymerization or copolymerization) of monomers having carbon-carbon unsaturated bonds.

[0186] In this invention, the polymer backbone refers to all linear molecular chains that constitute the polymer and can be considered branches or side groups relative to the backbone. While depending on the mass-average molecular weight of the branches or comb-like chains, typically the longest chain in the polymer's molecular chains becomes the backbone. However, terminal groups present at the ends of the polymer are not included in the backbone. Furthermore, polymer side chains refer to molecular chains other than the backbone, including both short and long chains.

[0187] The aforementioned bonds are not particularly limited as long as they are included in the polymer backbone. They can be included in structural units (repeating units) or as bonds connecting different structural units to each other. Furthermore, the backbone is not limited to one type of bond; it can contain two or more types, preferably one to six, and more preferably one to four. In this case, the bonding method of the backbone is not particularly limited; it can randomly contain two or more types of bonds, or it can be a segmented backbone consisting of segments with specific bonds and segments with other bonds.

[0188] There are no particular limitations on the main chain having the above-mentioned bonds. It is preferred to have a main chain having at least one segment of the above-mentioned bonds. More preferably, it is a main chain composed of polyamide, polyurea, polyurethane, or (meth)acrylic polymer. It is even more preferably a main chain composed of polyurethane or (meth)acrylic polymer.

[0189] Polymers that have urethane bonds, urea bonds, amide bonds, imide bonds, or ester bonds in their main chain, as mentioned above, include, for example, step-growth polymers (condensation, addition, or addition condensation) such as polyurethane, polyurea, polyamide, polyimide, and polyester, or copolymers thereof. The copolymer can be a block copolymer in which the aforementioned polymers are used as chain segments, or a random copolymer formed by the random bonding of the constituent components of two or more of the aforementioned polymers.

[0190] Polymers with carbon-carbon double bonds in their main chain, that is, polymers whose main chain consists of polymer chains formed by the polymerization of monomers with carbon-carbon unsaturated bonds, include chain polymers such as fluoropolymers (fluoropolymers), hydrocarbon polymers, vinyl polymers, and (meth)acrylic acid polymers. There are no particular restrictions on the polymerization method of these chain polymers; they can be any of the following: block copolymers, alternating copolymers, or random copolymers.

[0191] The polymers that form the above-mentioned adhesives can be one type or two or more types.

[0192] The polymer forming the above adhesive preferably has a constituent component represented by any one of the following formulas (1-1) to (1-5), and more preferably has a constituent component represented by the following formula (1-1) or formula (1-2).

[0193] [Chemical Formula 1]

[0194]

[0195] In equation (1-1), R 1 Represents a hydrogen atom or an alkyl group (preferably 1 to 12 carbon atoms, more preferably 1 to 6, and even more preferably 1 to 3). As R 1 The alkyl group that can be used may have substituents. There are no particular limitations on the substituents, and examples such as substituent Z described later can be given. Preferably, the substituents are groups other than those in functional group (a), such as halogen atoms.

[0196] R 2 This refers to a group having a hydrocarbon group having four or more carbon atoms. In this invention, a group having a hydrocarbon group includes a group consisting of the hydrocarbon group itself (the hydrocarbon group is directly bonded to R). 1 The carbon atoms in the above formula that are bonded. ) and the carbon atoms connected by R 2 The group formed by the carbon atom and the linking group of the hydrocarbon group in the above formula (the hydrocarbon group is bonded to R via the linking group) 1 The carbon atoms in the above formula that are bonded.

[0197] A hydrocarbon group is a group composed of carbon and hydrogen atoms, and is usually introduced into R. 2 The end group. There are no particular limitations on the hydrocarbon group, but it is preferably an aliphatic hydrocarbon group, more preferably an aliphatic saturated hydrocarbon group (alkyl), and even more preferably a straight-chain or branched alkyl group. The hydrocarbon group may have 4 or more carbon atoms, preferably 6 or more, more preferably 8 or more, and may also be 10 or more. There are no particular upper limits, but it is preferably 20 or less, more preferably 14 or less.

[0198] There are no particular limitations on the linking groups mentioned above. Examples include alkylene groups (preferably 1 to 12 carbon atoms, more preferably 1 to 6, and even more preferably 1 to 3), alkenyl groups (preferably 2 to 6 carbon atoms, more preferably 2 to 3), aryl groups (preferably 6 to 24 carbon atoms, more preferably 6 to 10), oxygen atoms, sulfur atoms, and imino groups (-NR). N -:R N This refers to groups including hydrogen atoms, alkyl groups with 1 to 6 carbon atoms or aryl groups with 6 to 10 carbon atoms, carbonyl groups, phosphate linkage groups (-OP(OH)(O)-O-), phosphonic acid linkage groups (-P(OH)(O)-O-), or combinations thereof. It is also possible to combine alkylene and oxygen atoms to form polyalkylene oxide chains. Preferably, the linking group is a group composed of alkylene, arylene, carbonyl, oxygen, sulfur, and imino groups; more preferably, it is a group composed of alkylene, arylene, carbonyl, oxygen, and imino groups; and even more preferably, it includes -CO-O- groups, -CO-N(R) groups, etc. N )-base(R N As described above, the group is particularly preferred to be -CO-O- or -CO-N(R) N )-base(R N As described above. The number of atoms constituting the linking group and the number of linking atoms are described later. However, the polyalkylene oxide chain constituting the linking group is not limited to the above.

[0199] In this invention, the number of atoms constituting the linking group is preferably 1 to 36, more preferably 1 to 24, even more preferably 1 to 12, and particularly preferably 1 to 6. The number of connecting atoms in the linking group is preferably 10 or less, more preferably 8 or less. A lower limit is 1 or more. The above-mentioned number of connecting atoms refers to the minimum number of atoms connecting the defined structural parts. For example, in the case of -CH2-C(=O)-O-, the number of atoms constituting the linking group is 6, but the number of connecting atoms is 3.

[0200] The aforementioned hydrocarbon group and the aforementioned linking group may or may not have substituents. As a possible substituent, substituent Z can be mentioned, and preferably a group other than the functional group in functional group (a) can be selected, such as a halogen atom.

[0201] In the above equation (1-1), with R 1 The carbon atoms adjacent to the bonded carbon atoms have two hydrogen atoms, but in this invention, they may have one or two substituents. There are no particular limitations on the substituents, and examples such as substituent Z described later can be used. Preferably, the substituents are groups other than those in functional group (a).

[0202] There are no particular limitations on the compounds that can be used to derive the constituents represented by formula (1-1), for example, straight-chain alkyl esters of (meth)acrylate (straight-chain alkyl refers to alkyl with 4 or more carbon atoms).

[0203] In equations (1-2) to (1-5), R 3 This refers to a linking group containing a polybutadiene chain or a polyisoprene chain with a mass-average molecular weight or number-average molecular weight (hereinafter referred to as mass-average molecular weight, etc.) of 500 or more and 200,000 or less.

[0204] R can be used 3 The end of the above chain can be appropriately changed to serve as R. 3 The usual chemical structures that can be incorporated into the constituents represented by the above formulas.

[0205] In the above formulas, R 3 It is a divalent molecular chain, but it can become a trivalent or higher chain by replacing at least one hydrogen atom with -NH-CO-, -CO-, -O-, -NH- or -N<.

[0206] R can be used 3 As long as the polybutadiene chain and polyisoprene chain satisfy the mass-average molecular weight, etc., known chains composed of polybutadiene and polyisoprene can be cited. Both polybutadiene and polyisoprene chains are diene polymers with double bonds in the main chain; however, in this invention, polymers in which the double bonds are hydrogenated (reduced) are included (e.g., non-diene polymers without double bonds in the main chain). In this invention, hydrides of polybutadiene or polyisoprene chains are preferred.

[0207] Polybutadiene chains and polyisoprene chains are preferably used as raw material compounds having reactive groups at their ends, more preferably having polymerizable terminal reactive groups. The polymerizable terminal reactive groups are polymerized to form R groups of the above formulas. 3 The bonded group. Examples of such terminal reactive groups include hydroxyl, carboxyl, and amino groups, with hydroxyl being preferred. Polybutadiene and polyisoprene with terminal reactive groups are preferably, for example, the NISSO-PB series (manufactured by NIPPON SODA CO.,LTD.), Claysol series (manufactured by TOMOE Engineering Co.,Ltd.), PolyVEST-HT series (manufactured by EVONIK CO.,LTD.), poly-bd series (manufactured by Idemitsu Kosan Co.,Ltd.), poly-ip series (manufactured by Idemitsu Kosan Co.,Ltd.), and EPOL (manufactured by Idemitsu Kosan Co.,Ltd.), all of which are trade names.

[0208] R can be used 3 The preferred mass-average molecular weight (converted to polystyrene) of the aforementioned chain is 500 to 200,000. The lower limit is preferably 500 or more, more preferably 700 or more, and even more preferably 1,000 or more. The upper limit is preferably 100,000 or less, more preferably 10,000 or less. For the raw material compound before it is incorporated into the polymer backbone, the mass-average molecular weight is determined by the method described later.

[0209] The content of the polymer containing any of the constituent components represented by formulas (1-1) to (1-5) above is not particularly limited, but is preferably 10 to 100 mol%. From the viewpoint of dispersion stability and adhesion, the content of the constituent component represented by formula (1-1) above is more preferably 30 to 98 mol%, and even more preferably 50 to 95 mol%. From the viewpoint of dispersion stability, the content of the constituent component represented by any of formulas (1-2) to (1-5) above is more preferably 30 to 98 mol%, and even more preferably 50 to 95 mol%. On the other hand, from the viewpoint of improving adhesion, it is preferably 0 to 90 mol%, more preferably 10 to 80 mol%, and even more preferably 20 to 70 mol%.

[0210] (Constitutes having functional groups selected from functional group (a))

[0211] The polymer forming at least one of polymeric adhesive A and polymeric adhesive B preferably comprises a constituent having functional groups selected from the functional group (a) below as, for example, substituents. Specifically, the polymer forming polymeric adhesive B preferably comprises a constituent having functional groups selected from the functional group (a) below. The constituent having functional groups has the function of improving the adsorption rate of the adhesive and can be any constituent forming the polymer. The functional groups can be incorporated into the main chain of the polymer or into the side chains. When incorporated into the side chains, the functional groups can be directly bonded to the main chain or bonded via the aforementioned linking groups. There are no particular limitations on the linking groups; examples of linking groups described later can be cited.

[0212] <Functional Groups (a)>

[0213] Hydroxyl, amino, carboxyl, sulfonyl, phosphate, phosphonic acid, thioalkyl, ether (-O-), imino (=NR, -NR-), ester (-CO-O-), amide (-CO-NR-), imide (-CO-NR-CO-), carbamate (-NR-CO-O-), urea (-NR-CO-NR-), heterocyclic, aryl, carboxylic anhydride

[0214] The functional group (a) is preferably composed of hydroxyl, amino, carboxyl, sulfonyl, phosphate, phosphonic acid, thioalkyl, ether bond, imino, amide bond, imide, carbamate bond, urea bond, heterocyclic group, aryl, and carboxylic anhydride group.

[0215] The amino, sulfonyl, phosphate (phosphoryl), heterocyclic, and aryl groups included in functional group (a) are not particularly limited and have the same meaning as the corresponding groups of substituent Z described later. The amino group preferably has 0 to 12 carbon atoms, more preferably 0 to 6, and especially preferably 0 to 2. There are no particular limitations on the phosphonic acid group; for example, phosphonic acid groups with 0 to 20 carbon atoms can be cited. When an amino group, ether bond, imino group (-NR-), ester bond, amide bond, imide group, carbamate bond, urea bond, etc., are included in the ring structure, it is classified as a heterocycle. There are no particular limitations on the heterocycle containing an imide group in the ring structure; for example, the carboxylic anhydride group described later, or the "-CO-O-CO-" group in formula (2a) or (2b) can be replaced with "CO-NR". I A ring with a "-CO-" group. Among them, R I This represents a hydrogen atom or a substituent. There are no particular restrictions on the substituent; it is selected from substituent Z described later, and preferably alkyl. Hydroxyl, amino, carboxyl, sulfonyl, phosphate, phosphonic acid, and thioalkyl groups can form salts.

[0216] In each bond, R represents a hydrogen atom or a substituent, preferably a hydrogen atom. There are no particular restrictions on the substituents, which are selected from substituents Z described later, and are preferably alkyl groups.

[0217] R in imide group I As stated above.

[0218] There are no particular limitations on the carboxylic anhydride group, which includes groups formed by removing one or more hydrogen atoms from a carboxylic anhydride (e.g., groups represented by formula (2a) below), and further includes the constituent components themselves formed by copolymerizing polymerizable carboxylic anhydrides as copolymerizable compounds (e.g., constituent components represented by formula (2b) below). As a group formed by removing one or more hydrogen atoms from a carboxylic anhydride, it is preferable to have a group formed by removing one or more hydrogen atoms from a cyclic carboxylic anhydride. Carboxylic anhydride groups derived from cyclic carboxylic anhydrides are also equivalent to heterocyclic groups, but are classified as carboxylic anhydride groups in this invention. Examples include acyclic carboxylic anhydrides such as acetic anhydride, propionic anhydride, and benzoic acid rod, and cyclic carboxylic anhydrides such as maleic anhydride, phthalic anhydride, fumaric acid rod, and succinic anhydride. There are no particular limitations on the polymerizable carboxylic anhydride, and carboxylic anhydrides having intramolecular unsaturated bonds can be cited, with polymerizable cyclic carboxylic anhydrides being preferred. Specifically, maleic anhydride can be cited.

[0219] Examples of carboxylic anhydride groups include groups represented by formula (2a) or constituents represented by formula (2b), but the invention is not limited to these. In each formula, * indicates a bonding position.

[0220] [Chemical Formula 2]

[0221]

[0222] In stepwise polymer polymerization, when the chemical structure of the polymer is represented by components derived from the starting material compounds, ester bonds (-CO-O-), amide bonds (-CO-NR-), urethane bonds (-NR-CO-O-), and urea bonds (-NR-CO-NR-) are respectively represented by -CO- and -O- groups, -CO- and -NR- groups, -NR-CO- and -O- groups, and -NR-CO- and -NR- groups. Therefore, in this invention, components having these bonds are designated as components derived from carboxylic acid compounds or isocyanate compounds, regardless of the polymer labeling, and do not include components derived from polyols or polyamines.

[0223] Furthermore, in chain polymers, components with ester bonds (excluding ester bonds that form carboxyl groups) refer to components whose ester bonds are not directly bonded to the atoms of the main chain of the chain polymer, or to the main chain of the polymer chain (e.g., the polymer chain of a macromonomer) that is incorporated into the chain polymer as a branch or comb chain. For example, components not derived from alkyl methacrylates.

[0224] In this invention, it is preferable to incorporate amino, ether, imino, ester, amide, carbamate, urea, heterocyclic, and aryl groups into the side chains of the polymer.

[0225] A constituent component may have one or more functional groups. When it has two or more functional groups, they may or may not be bonded to each other. Furthermore, there is no particular limitation on the number of functional groups a constituent component may have; it may have one or more, or it may have one to four.

[0226] There are no particular limitations on the linking group that bonds the functional group to the main chain, except for the following particularly preferred linking groups, which can be used with R as shown in formula (1-1) above. 2 The meaning of a linking group in a group having a hydrocarbon group having 4 or more carbon atoms is the same. As a linking group that bonds the functional group to the main chain, a particularly preferred linking group is a -CO-O- group or a -CO-N(R) group. N )-base(R N As described above, ) is a group formed by combining with alkylene or polyalkylene oxide chains.

[0227] There are no particular restrictions on the constituent having the above-mentioned functional groups. Examples include constituents that have introduced the above-mentioned functional groups into any of the constituents represented by formulas (1-1) to (1-5), constituents represented by formulas (I-1) or (I-2) described later, constituents derived from compounds represented by formula (I-5) described later, constituents that have introduced the above-mentioned functional groups into constituents represented by formulas (I-3) or (I-4) described later or constituents derived from compounds represented by formula (I-6), as well as (meth)acrylic acid compound (M1) or other polymeric compound (M2) described later, and constituents that have introduced the above-mentioned functional groups into any of the constituents represented by formulas (b-1) to (b-3) described later.

[0228] There are no particular limitations on the compounds that introduce the above-mentioned functional groups as constituents. For example, compounds that introduce the above-mentioned functional groups into short-chain alkyl ester compounds of (meth)acrylate (short-chain alkyl refers to alkyl with 3 or fewer carbon atoms) can be cited.

[0229] There are no particular restrictions on the content of the constituent components with the above functional groups in the polymer.

[0230] In step-polymer polymers, considering the dispersion characteristics and adhesion of solid particles, the preferred content is 0.01 to 50 mol%, more preferably 0.1 to 50 mol%, and even more preferably 0.3 to 50 mol%. In chain polymer polymers, considering the dispersion characteristics and adhesion of solid particles, the preferred content is 0.01 to 80 mol%, more preferably 0.01 to 70 mol%, even more preferably 0.1 to 50 mol%, and particularly preferably 0.3 to 50 mol%. The upper limit of the content can also be set to 30 mol% or less or 10 mol% or less. In both step-polymer polymers and chain polymer polymers, the lower limit of the content can also be set to 1 mol% or more, 5 mol% or more, or 20 mol% or more.

[0231] -Step-growth polymer-

[0232] The stepwise polymer of the polymer forming the above-mentioned adhesive preferably has the constituent components having functional groups selected from functional group (a) or the constituent components represented by any one of formulas (1-2) to (1-5), and may also have constituent components different from these constituent components. Among the constituent components shown below, the constituent components represented by formula (I-1) or formula (I-2), and the constituent components derived from the compound represented by formula (I-5) are also equivalent to constituent components having functional groups selected from functional group (a), but are described together with other constituent components. Other constituent components may include, for example, one or more of the constituent components represented by formula (I-1) or (I-2) below, and further, the constituent components represented by formula (I-3) or (I-4) below (preferably 1 to 8, more preferably 1 to 4), or constituent components formed by stepwise polymerization of a carboxylic dianhydride represented by formula (I-5) and a diamine compound incorporating a constituent component represented by formula (I-6) below. The combination of components can be appropriately selected according to the type of polymer. Using one component in a combination of components refers to a component represented by any one of the following formulas; even if two components represented by one of the following formulas are included, they will not be interpreted as two components.

[0233] [Chemical Formula 3]

[0234]

[0235] In the formula, R P1 and R P2 These refer to molecular chains with a (mass-average) molecular weight of 20 or more and 200,000 or less. The molecular weight of this chain depends on its type and other factors, and therefore cannot be uniquely determined. For example, 30 or more is preferred, 50 or more is more preferred, 100 or more is even more preferred, and 150 or more is particularly preferred. As an upper limit, 100,000 or less is preferred, and 10,000 or less is more preferred. The molecular weight of the molecular chain is determined from the starting material compound before it is incorporated into the polymer backbone.

[0236] R can be used P1 and R P2 The molecular chain is not particularly limited, but is preferably a hydrocarbon chain, a polyoxyalkylene chain, a polycarbonate chain or a polyester chain, more preferably a hydrocarbon chain or a polyoxyalkylene chain, and even more preferably a hydrocarbon chain, a polyoxyethylene chain or a polyoxypropylene chain.

[0237] R P1 and R P2The hydrocarbon chain that can be used refers to a hydrocarbon chain composed of carbon atoms and hydrogen atoms, and more specifically, refers to a structure in which at least two atoms (e.g., hydrogen atoms) or groups (e.g., methyl groups) in a compound composed of carbon atoms and hydrogen atoms are detached. However, in this invention, for example, as a hydrocarbon group represented by the following formula (M2), the hydrocarbon chain also includes a chain having groups containing oxygen atoms, sulfur atoms, or nitrogen atoms. Terminal groups that may be present at the end of the hydrocarbon chain are not included in the hydrocarbon chain. The hydrocarbon chain may have carbon-carbon unsaturated bonds, or it may have a ring structure of aliphatic rings and / or aromatic rings. That is, the hydrocarbon chain can be a hydrocarbon chain composed of hydrocarbons selected from aliphatic hydrocarbons and aromatic hydrocarbons.

[0238] As long as the above molecular weight is met, such hydrocarbon chains can be either chains composed of low molecular weight hydrocarbon groups or hydrocarbon chains composed of hydrocarbon polymers (also called hydrocarbon polymer chains).

[0239] The low molecular weight hydrocarbon chain is a chain composed of ordinary (non-polymeric) hydrocarbon groups. Examples of such hydrocarbon groups include aliphatic or aromatic hydrocarbon groups. Specifically, alkylene groups (preferably with 1 to 12 carbon atoms, more preferably 1 to 6, and even more preferably 1 to 3), arylene groups (preferably with 6 to 22 carbon atoms, more preferably 6 to 14, and even more preferably 6 to 10), or combinations thereof are preferred. As a group forming R... P2 The hydrocarbon group of the low molecular weight hydrocarbon chain that can be used is more preferably alkylene, further preferably alkylene with 2 to 6 carbon atoms, and especially preferably alkylene with 2 or 3 carbon atoms. The hydrocarbon chain may have a polymer chain (e.g., (meth)acrylic acid polymer) as a substituent.

[0240] There are no particular limitations on aliphatic hydrocarbon groups; examples include hydrogen reductions of aromatic hydrocarbon groups represented by the following formula (M2), partial structures of known aliphatic diisocyanate compounds (e.g., groups composed of isophorone), etc.

[0241] Aromatic hydrocarbon groups can be exemplified by the hydrocarbon groups contained in the constituents described below, preferably arylene groups (e.g., groups obtained by further removing one or more hydrogen atoms from aryl groups listed in substituent Z below, specifically phenylene, methylphenylene or xylene) or hydrocarbon groups represented by the following formula (M2).

[0242] [Chemical Formula 4]

[0243]

[0244] In formula (M2), X represents a single bond, -CH2-, -C(CH3)2-, -SO2-, -S-, -CO-, or -O-. From the viewpoint of adhesion, -CH2- or -O- is preferred, and -CH2- is more preferred. The alkylene groups and methyl groups illustrated herein may be substituted with substituents Z, preferably with halogen atoms (more preferably fluorine atoms).

[0245] R M2 ~R M5 These represent hydrogen atoms or substituents, preferably hydrogen atoms. As R... M2 ~R M5 There are no particular limitations on the substituents that can be used; for example, alkyl groups with 1 to 20 carbon atoms, alkenyl groups with 1 to 20 carbon atoms, and -OR groups can be used. M6 、―N(R M6 )2、-SR M6 (R M6 The substituent is indicated, preferably an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 10 carbon atoms. The halogen atom (e.g., fluorine, chlorine, bromine) is also indicated. As -N(R M6 )2, Examples include alkylamino (preferably 1 to 20 carbon atoms, more preferably 1 to 6) or arylamino (preferably 6 to 40 carbon atoms, more preferably 6 to 20).

[0246] The hydrocarbon polymer chain is a polymer chain formed by the polymerization of polymerizable hydrocarbons (at least two). There are no particular limitations as long as the chain is a hydrocarbon polymer chain containing a hydrocarbon chain with a carbon number greater than the aforementioned low molecular weight hydrocarbon chain, and it is preferably a chain containing a hydrocarbon polymer chain composed of 30 or more carbon atoms, more preferably 50 or more carbon atoms. There is no particular upper limit on the number of carbon atoms constituting the hydrocarbon polymer; for example, it can be set to 3,000. This hydrocarbon polymer chain is preferably a chain whose main chain contains a hydrocarbon polymer composed of aliphatic hydrocarbons satisfying the aforementioned number of carbon atoms, and more preferably a chain containing a polymer (preferably an elastomer) composed of aliphatic saturated hydrocarbons or aliphatic unsaturated hydrocarbons. Specifically, examples of polymers include diene polymers having double bonds in the main chain and non-diene polymers not having double bonds in the main chain. Examples of diene polymers include styrene-butadiene copolymers, styrene-vinyl-butadiene copolymers, copolymers of isobutylene and isoprene (preferably butyl rubber (IIR)), and vinyl-propylene-diene copolymers. Examples of non-diene polymers include olefin polymers such as vinyl-propylene copolymers and styrene-vinyl-propylene copolymers, as well as hydrogen-reduced products of the aforementioned diene polymers.

[0247] The hydrocarbon forming the hydrocarbon chain preferably has a reactive group at its terminal, more preferably a terminal reactive group capable of condensation polymerization. The terminal reactive group capable of condensation or addition polymerization forms R, which is bonded to the above formulas, through condensation or addition polymerization.P1 Or R P2 The terminal reactive group can be categorized as isocyanate group, hydroxyl group, carboxyl group, amino group, and acid anhydride group, with hydroxyl group being preferred.

[0248] Hydrocarbon polymers with terminal reactive groups, such as the NISSO-PB series (manufactured by NIPPONSODA CO.,LTD.), Claysol series (manufactured by TOMOE Engineering Co.,Ltd.), PolyVEST-HT series (manufactured by EVONIK CO.,LTD.), poly-bd series (manufactured by Idemitsu Kosan Co.,Ltd.), poly-ip series (manufactured by Idemitsu Kosan Co.,Ltd.), EPOL (manufactured by Idemitsu Kosan Co.,Ltd.), and POLYTAIL series (manufactured by Mitsubishi Chemical Corporation), are preferred. These are all trade names.

[0249] Examples of polyalkylene oxide chains (polyalkylene oxide chains) include chains composed of known polyalkylene oxides. The number of carbon atoms in the alkylene oxides of the polyalkylene oxide chain is preferably 1 to 10, more preferably 1 to 6, and even more preferably 2 or 3 (polyethylene oxide chains or polypropylene oxide chains). The polyalkylene oxide chain can be a chain composed of one type of alkylene oxide, or a chain composed of two or more types of alkylene oxides (e.g., a chain composed of ethylene oxide and propylene oxide).

[0250] Examples of polycarbonate chains or polyester chains include chains made of known polycarbonate or polyester.

[0251] The polyalkylene oxide chain, polycarbonate chain, or polyester chain preferably has an alkyl group at the end (preferably 1 to 12 carbon atoms, more preferably 1 to 6).

[0252] R P1 and R P2 The ends of the polyalkylene oxide chains, polycarbonate chains, and polyester chains that can be used can be appropriately modified to serve as R. P1 and R P2 The common chemical structures that can be incorporated into the constituents represented by the above formulas. For example, the polyalkylene oxide chain, by removing the terminal oxygen atom, serves as the R of the above-mentioned constituent. P1 Or R P2 And included.

[0253] The alkyl group contained in the molecular chain may have an ether group (-O-), a thioether group (-S-), a carbonyl group (>C=O), or an imino group (>NR) inside or at the end.N :R N It consists of hydrogen atoms, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms.

[0254] In the above formulas, R P1 and R P2 It is a divalent molecular chain, but at least one hydrogen atom can be replaced by -NH-CO-, -CO-, -O-, -NH- or -N< to become a trivalent or higher molecular chain.

[0255] R P1 The aforementioned molecular chains are preferably hydrocarbon chains, more preferably low molecular weight hydrocarbon chains, and even more preferably hydrocarbon chains composed of aliphatic or aromatic hydrocarbon groups, especially hydrocarbon chains composed of aliphatic hydrocarbon groups.

[0256] R P2 The molecular chains mentioned above are preferably low molecular weight hydrocarbon chains (more preferably aliphatic hydrocarbon groups) or molecular chains other than low molecular weight hydrocarbon chains (more preferably polyoxyalkylene chains).

[0257] Specific examples of the constituent components represented by formula (I-1) above are shown in the following examples and embodiments. Furthermore, examples of the isocyanate compounds (isocyanate compounds) into which the constituent components represented by formula (I-1) are introduced include, for example, the isocyanate compound represented by formula (M1) described in International Publication No. 2018 / 020827 and specific examples thereof, and further examples include polymerized 4,4'-diphenylmethane isocyanate. In addition, in this invention, the constituent components represented by formula (I-1) and the raw material compounds into which they are introduced are not limited to the specific examples, embodiments, and contents described in the aforementioned documents.

[0258] [Chemical Formula 5]

[0259]

[0260] There are no particular limitations on the raw material compound (carboxylic acid or its acyl chloride, etc.) that is a constituent component represented by the above formula (I-2). For example, compounds of carboxylic acid or acyl chloride described in paragraph

[0074] of International Publication No. 2018 / 020827 and specific examples thereof (e.g., adipic acid or its esters) can be cited.

[0261] Specific examples of the constituents represented by formulas (I-3) or (I-4) above are shown in the following examples and embodiments. Furthermore, there are no particular limitations on the starting material compounds (diol compounds or diamine compounds) into which the constituents represented by formulas (I-3) or (I-4) above are introduced; for example, the compounds and specific examples described in International Publication No. 2018 / 020827 can be cited, and dihydroxyacetamide can also be cited. In addition, in this invention, the constituents represented by formulas (I-3) or (I-4) and the starting material compounds into which they are introduced are not limited to the specific examples below, the exemplary polymers described later, the examples, and the contents described in the aforementioned documents.

[0262] Furthermore, in the specific examples below, when the constituent components have repeating structures, the number of repeats is an integer of 1 or more, which is appropriately set within the range that satisfies the molecular weight or number of carbon atoms of the molecular chain described above.

[0263] [Chemical Formula 6]

[0264]

[0265] In equation (I-5), R P3 The linking group (4-valent) represents an aromatic or aliphatic group, preferably a linking group represented by any one of the following formulas (i) to (iix).

[0266] [Chemical Formula 7]

[0267]

[0268] In equations (i) to (iix), X 1 This indicates a single bond or a divalent linking group. As a divalent linking group, an alkylene group having 1 to 6 carbon atoms is preferred (e.g., methylene, vinyl, propenyl). As a propenyl group, 1,3-hexafluoro-2,2-propanediol is preferred. L represents -CH2=CH2- or -CH2-. R X and R Y These represent hydrogen atoms or substituents, respectively. In each formula, * indicates the bonding site with the carbonyl group in formula (I-5). As R X and R Y There are no particular limitations on the substituents that can be used. Examples of substituents Z described later are given, with alkyl groups (preferably 1 to 12 carbon atoms, more preferably 1 to 6, and even more preferably 1 to 3) or aryl groups (preferably 6 to 22 carbon atoms, more preferably 6 to 14, and even more preferably 6 to 10).

[0269] There are no particular limitations on the carboxylic acid dianhydride represented by formula (I-5) above and the starting material compound (diamine compound) that introduces the constituent element represented by formula (I-6) above. For example, the compounds and specific examples described in International Publication No. 2018 / 020827 and International Publication No. 2015 / 046313 can be cited.

[0270] R P1 R P2 and R P3 Each may have substituents. There are no particular limitations on the substituents; for example, substituent Z described later or any of the groups included in the functional group (a) above can be mentioned, with R being a preferred example. M2 The above-mentioned substituents that can be used.

[0271] When the polymer forming the above-mentioned adhesive is a step-polymer polymer, it has a constituent component represented by any one of the above formulas (1-1) to (1-5), preferably a constituent component having a functional group selected from functional group (a) (including the constituent component represented by formula (I-1) below), and may also have a constituent component represented by formula (I-3), formula (I-4) or formula (I-5) above. As a constituent component represented by formula (I-3), at least one of the constituent components represented by formulas (I-3A) to (I-3C) below can be cited. The constituent component represented by formula (I-4) is also the same as the constituent component represented by formula (I-3), except that the oxygen atom is replaced by a nitrogen atom in each of the formulas (I-3A) to (I-3C) below.

[0272] [Chemical Formula 8]

[0273]

[0274] In equation (I-1), R P1 As described above. In equation (I-3A), R P2A This represents a chain composed of low molecular weight hydrocarbon groups (preferably aliphatic hydrocarbon groups). In formula (I-3B), R P2B This represents a polyalkylene oxide chain. In formula (I-3C), R P2C This represents a hydrocarbon polymer chain. It can be represented by R. P2A Chains composed of low molecular weight hydrocarbon groups can be used as R... P2B The polyalkylene oxide chain and its potential use as R P2C The meanings of the hydrocarbon polymer chains are respectively the same as those of the R in the above formula (I-3). P2 The aliphatic hydrocarbon groups, polyalkylene oxide chains, and hydrocarbon polymer chains have the same meaning, and the preferred ones are also the same.

[0275] The polymer (step-polymerizable polymer) forming the above-described adhesive may have components other than those represented by the formulas above. There are no particular limitations as long as such components are capable of step-polymerization with the raw material compound to which the components represented by the formulas above are introduced.

[0276] The total content of the constituent components represented by formulas (I-1) to (I-6) in the polymer forming the above adhesive is not particularly limited, but is preferably 5 to 100 mol%, more preferably 5 to 80 mol%, and even more preferably 10 to 60 mol%. The upper limit of this content can be set to 100 mol% or less, for example, regardless of the above 60 mol%.

[0277] The content of the components in the polymer forming the above adhesive, other than those represented by the above formulas, is not particularly limited, but is preferably 50 mol% or less.

[0278] When the polymer forming the above adhesive has a component represented by any one of the above formulas (I-1) to (I-6), its content is not particularly limited and can be appropriately selected, for example, it can be set within the following range.

[0279] That is, there is no particular limitation on the content of the constituent component represented by formula (I-1) or formula (I-2) or the constituent component of carboxylic acid dianhydride represented by formula (I-5) in the polymer forming the above adhesive, but it is preferably the same as the content of the constituent component having functional groups.

[0280] The content of the constituent components represented by formula (I-3), formula (I-4) or formula (I-6) in the polymer forming the above adhesive is not particularly limited, but is preferably 1 to 80 mol%, more preferably 10 to 80 mol%, even more preferably 20 to 70 mol%, and particularly preferably 30 to 60 mol%.

[0281] The content of each component represented by any one of the above formulas (I-3A) to (I-3C) is appropriately set by taking into account the content of the component represented by the above formula (I-3).

[0282] Furthermore, when the polymer forming the above-mentioned adhesive has multiple constituent components represented by various formulas, the above-mentioned content of each constituent component is set as the total content.

[0283] The polymer (constituent components and raw material compounds) that forms the above-mentioned adhesive may have substituents. There are no particular limitations on the substituents, but groups selected from substituent Z below are preferred.

[0284] The polymer that forms the above-mentioned adhesive can be synthesized as follows: a starting compound is selected according to the type of bonds in the main chain and by known methods, and the starting compound is subjected to addition polymerization or condensation polymerization, etc. For example, International Publication No. 2018 / 151118 can be referred to as a synthesis method.

[0285] There are no particular limitations on the methods for incorporating functional groups. For example, methods such as copolymerizing compounds having functional groups selected from functional group (a), using polymerization initiators having (generating) the aforementioned functional groups, and utilizing polymer reactions can be cited.

[0286] Polyurethane, polyurea, polyamide, and polyimide polymers that can be used to form the above-mentioned adhesives include, in addition to the exemplary polymers described below and those synthesized in the examples, polymers described in International Publication No. 2018 / 020827, International Publication No. 2015 / 046313, and further Japanese Patent Application Publication No. 2015-088480.

[0287] -Substituent Z-

[0288] Examples of alkyl groups include alkyl groups (preferably alkyl groups with 1 to 20 carbon atoms, such as methyl, ethyl, isopropyl, tert-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.), alkenyl groups (preferably alkenyl groups with 2 to 20 carbon atoms, such as vinyl, allyl, oleyl, etc.), alkynyl groups (preferably alkynyl groups with 2 to 20 carbon atoms, such as ethynyl, butyrynyl, phenylethynyl, etc.), and cycloalkyl groups (preferably cycloalkyl groups with 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc.). When the alkyl group is used in this invention, it is generally... This indicates the presence of cycloalkyl groups, but is described separately here. Aryl groups (preferably aryl groups with 6 to 26 carbon atoms, such as phenyl, 1-naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methylphenyl, etc.), aralkyl groups (preferably aralkyl groups with 7 to 23 carbon atoms, such as benzyl, phenethyl, etc.), heterocyclic groups (preferably heterocyclic groups with 2 to 20 carbon atoms, more preferably heterocyclic groups with a 5 or 6-membered ring having at least one oxygen atom, sulfur atom, and nitrogen atom). Heterocyclic groups include aromatic heterocyclic groups and aliphatic heterocyclic groups. Examples include tetrahydropyranyl, tetrahydrofuranyl, and 2-pyridine. The following groups are listed: 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-oxazolyl, pyrrolidone, etc.); alkoxy groups (preferably alkoxy groups with 1 to 20 carbon atoms, such as methoxy, ethoxy, isopropoxy, benzyloxy, etc.); aryloxy groups (preferably aryloxy groups with 6 to 26 carbon atoms, such as phenoxy, 1-naphthoxy, 3-methylphenoxy, 4-methoxyphenoxy, etc.); heterocyclic oxy groups (groups with a -O- group bonded to the above heterocyclic groups); alkoxycarbonyl groups (preferably alkoxycarbonyl groups with 2 to 20 carbon atoms, such as ethoxycarbonyl, 2-ethylhexyloxycarbonyl, etc.). Dodecyloxycarbonyl, etc.), aryloxycarbonyl (preferably aryloxycarbonyl with 6 to 26 carbon atoms, such as phenoxycarbonyl, 1-naphthoxycarbonyl, 3-methylphenoxycarbonyl, 4-methoxyphenoxycarbonyl, etc.), heterocyclic oxycarbonyl (a group with -O-CO- group bonded to the above heterocyclic group), amino (preferably containing amino, alkylamino, arylamino with 0 to 20 carbon atoms, such as amino(-NH2), N,N-dimethylamino, N,N-diethylamino, N-ethylamino, aniline, etc.), aminosulfonyl (preferably aminosulfonyl with 0 to 20 carbon atoms, such as N,N-dimethylaminosulfonyl, N-phenylaminosulfonyl, etc.), acyl groups (including alkyl carbonyl, alkenyl carbonyl, alkynyl carbonyl, aryl carbonyl, heterocyclic carbonyl, preferably acyl groups with 1 to 20 carbon atoms, such as acetyl, propionyl, butyryl, octanoyl, hexadecanoyl, acryl, methacryl, crotonyl, benzoyl, naphthoyl, nicotinyl, etc.), acyloxy groups (including alkyl carbonyloxy, alkenyl carbonyloxy, alkynyl carbonyloxy, heterocyclic carbonyloxy, preferably acyloxy groups with 1 to 20 carbon atoms, such as acetyloxy, propionyloxy, butyryloxy, octanoyloxy, hexadecanoyl, etc.), Acryloyloxy, methacryloyloxy, crotonyloxy, nicotinoxy, etc.), aromatic acryloyloxy (preferably aromatic acryloyloxy with 7 to 23 carbon atoms, such as benzoyloxy, naphthyloxy, etc.), carbamoyl (preferably carbamoyl with 1 to 20 carbon atoms, such as N,N-dimethylcarbamoyl, N-phenylcarbamoyl, etc.), amide (preferably amide with 1 to 20 carbon atoms, such as acetamido, benzoylamino, etc.), alkylthio (preferably alkylthio with 1 to 20 carbon atoms, such as methylthio, ethylthio, isopropylthio, benzylthio, etc.) Arylthioyl (preferably arylthioyl with 6 to 26 carbon atoms, such as phenylthioyl, 1-naphthioyl, 3-methylphenylthioyl, 4-methoxyphenylthioyl, etc.), heterocyclic thioyl (a group with -S- group bonded to the above heterocyclic group), alkylsulfonyl (preferably alkylsulfonyl with 1 to 20 carbon atoms, such as methylsulfonyl, ethylsulfonyl, etc.), arylsulfonyl (preferably arylsulfonyl with 6 to 22 carbon atoms, such as benzenesulfonyl, etc.), alkylsilyl (preferably alkylsilyl with 1 to 20 carbon atoms, such as monomethylsilyl, dimethylsilyl, trimethylsilyl, etc.). alkylsilyl, triethylsilyl, etc.), arylsilyl (preferably arylsilyl with 6 to 42 carbon atoms, such as triphenylsilyl), alkoxysilyl (preferably alkoxysilyl with 1 to 20 carbon atoms, such as monomethoxysilyl, dimethoxysilyl, trimethoxysilyl, triethoxysilyl, etc.), aryloxysilyl (preferably aryloxysilyl with 6 to 42 carbon atoms, such as triphenoxysilyl), phosphoryl (preferably phosphoric acid with 0 to 20 carbon atoms, such as -OP(=O)(R, P )2) Phosphonyl group (preferably a phosphonyl group with 0 to 20 carbon atoms, for example, -P(=O)(R P )2) Oxyphosphin group (preferably oxyphosphin group with 0 to 20 carbon atoms, for example, -P(R P 2) Phosphonic acid group (preferably a phosphonic acid group with 0 to 20 carbon atoms, for example, -PO(OR) P 2) Sulfonate (sulfonic acid group), carboxyl group, hydroxyl group, thioalkyl group, cyano group, halogen atom (e.g., fluorine atom, chlorine atom, bromine atom, iodine atom, etc.). R PIt is a hydrogen atom or a substituent (preferably a group selected from substituent Z).

[0289] Furthermore, each of the groups listed in these substituents Z can be further replaced by the aforementioned substituents Z.

[0290] The aforementioned alkyl, alkylene, alkenyl, alkenylene, ynyl and / or ynylene groups can be cyclic or chain-like, and can be straight-chain or branched.

[0291] -Chain polymer-

[0292] The chain polymer that forms the above-mentioned adhesive will be described.

[0293] The chain polymer preferably has the constituent components having functional groups selected from functional group (a) or the constituent components represented by formula (1-1) above, more preferably it includes the constituent components having the functional groups described above and the constituent components represented by formula (1-1), and may also have constituent components different from these constituent components. The chain polymer may be a polymer that does not contain the constituent components having functional groups selected from functional group (a) or the constituent components represented by formula (1-1) above, but is composed of another constituent component.

[0294] Examples of fluoropolymers include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), copolymers of PVdF and hexafluoropropylene (PVdF-HFP), and copolymers of PVdF, hexafluoropropylene, and tetrafluoroethylene (PVdF-HFP-TFE). In PVdF-HFP, the copolymerization ratio of PVdF to HFP [PVdF:HFP] (mass ratio) is not particularly limited, but is preferably 9:1 to 5:5, and more preferably 9:1 to 7:3 from the viewpoint of adhesion. In PVdF-HFP-TFE, the copolymerization ratio of PVdF to HFP and TFE [PVdF:HFP:TFE] (mass ratio) is not particularly limited, but is preferably 20 to 60:10 to 40:5 to 30, and more preferably 25 to 50:10 to 35:10 to 25.

[0295] Examples of hydrocarbon polymers include polyethylene, polypropylene, natural rubber, polybutadiene, polyisoprene, polystyrene, polystyrene-butadiene copolymers, styrene-based thermoplastic elastomers, polybutene, acrylonitrile-butadiene copolymers, or their hydrogenated (hydrogenated) polymers. There are no particular limitations on styrene-based thermoplastic elastomers or their hydrogenated derivatives; examples include styrene-ethylene-butene-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 of SEBS and other block copolymers corresponding to the aforementioned block copolymers. In this invention, the preferred feature of the hydrocarbon polymer is that the polymer without unsaturated groups (e.g., 1,2-butadiene components) bonded to the main chain can suppress the formation of chemical crosslinks.

[0296] Examples of vinyl polymers include polymers containing 50 mol% or more of vinyl monomers other than (meth)acrylic acid compound (M1). Examples of vinyl monomers include vinyl compounds described later. Specifically, examples of vinyl polymers include polyvinyl alcohol, polyvinyl acetal, polyvinyl acetate, or copolymers containing these.

[0297] The vinyl polymer preferably contains, in addition to components derived from vinyl monomers, components derived from a (meth)acrylic acid compound (M1) that form the (meth)acrylic acid polymer described later. The content of the components derived from vinyl monomers is preferably the same as the content of the components derived from (meth)acrylic acid compound (M1) in the (meth)acrylic acid polymer. There is no particular limitation on the content of the components derived from (meth)acrylic acid compound (M1) in the polymer, provided it is less than 50 mol%, but it is preferably 0 to 30 mol%.

[0298] As a (meth)acrylic acid polymer, the preferred other constituent component is a polymer obtained by copolymerizing at least one (meth)acrylic acid compound (M1) selected from (meth)acrylic acid compounds, (meth)acrylic ester compounds, (meth)acrylamide compounds, and (meth)acrylonitrile compounds. Furthermore, a (meth)acrylic acid polymer composed of a copolymer of (meth)acrylic acid compound (M1) and another polymerizable compound (M2) is also preferred. There are no particular limitations on the other polymerizable compound (M2), and examples include styrene compounds, vinylnaphthalene compounds, vinyl carbazole compounds, allyl compounds, vinyl ether compounds, vinyl ester compounds, itaconic acid dialkyl compounds, unsaturated carboxylic anhydrides, and their fluorides. Examples of vinyl compounds include, for instance, the "ethylene monomers" described in Japanese Patent Application Publication No. 2015-88486.

[0299] (Meth)acrylic acid compounds (M1) and other polymeric compounds (M2) may have substituents. As substituents, there are no particular limitations as long as they are groups other than those included in the functional group (a) above, but groups selected from the substituents Z above are preferred.

[0300] There are no particular restrictions on the content of other polymeric compounds (M2) in (meth)acrylic acid polymers, for example, it can be set to less than 50 mol%.

[0301] The (meth)acrylic acid compound (M1) and the vinyl compound (M2) used as constituent components of the introduced (meth)acrylic acid polymer and vinyl polymer are preferably compounds represented by the following formula (b-1). This compound is different from the constituent components having the functional groups included in the above-described functional group (a) and the constituent components represented by the above-described formula (1-1).

[0302] [Chemical Formula 9]

[0303]

[0304] In the formula, R 1 The group represents a hydrogen atom, hydroxyl group, cyano group, halogen atom, alkyl group (preferably with 1 to 24 carbon atoms, more preferably 1 to 12, especially preferably 1 to 6), alkenyl group (preferably with 2 to 24 carbon atoms, more preferably 2 to 12, especially preferably 2 to 6), alkynyl group (preferably with 2 to 24 carbon atoms, more preferably 2 to 12, especially preferably 2 to 6), or aryl group (preferably with 6 to 22 carbon atoms, more preferably 6 to 14). Among these, hydrogen atoms or alkyl groups are preferred, and hydrogen atoms or methyl groups are even more preferred.

[0305] R 2 Represents a hydrogen atom or substituent. It can be represented as R. 2The substituents are not particularly limited, and examples include alkyl (which may be branched, but preferably straight), alkenyl (preferably with 2 to 12 carbon atoms, more preferably 2 to 6, especially preferably 2 or 3), aryl (preferably with 6 to 22 carbon atoms, more preferably 6 to 14), aralkyl (preferably with 7 to 23 carbon atoms, more preferably 7 to 15), and cyano.

[0306] The alkyl group preferably has 1 to 3 carbon atoms. The alkyl group may have groups other than those included in the functional group (a) of the above-described substituent Z.

[0307] L 1 The linking group is not particularly limited, and examples include alkylene groups with 1 to 6 carbon atoms (preferably 1 to 3), alkenyl groups with 2 to 6 carbon atoms (preferably 2 to 3), aryl groups with 6 to 24 carbon atoms (preferably 6 to 10), oxygen atoms, sulfur atoms, and imino groups (-NR). N -:R N As mentioned above, groups including carbonyl groups, phosphate linkage groups (-OP(OH)(O)-O-), phosphonic acid linkage groups (-P(OH)(O)-O-), or combinations thereof, preferably -CO-O- or -CO-N(R)-. N )-base(R N As described above. The linking group can have any substituents. The number of atoms constituting the linking group and the number of linking atoms are described later. Examples of arbitrary substituents include the aforementioned substituent Z, such as alkyl or halogen atoms.

[0308] n is 0 or 1, preferably 1. Where, -(L 1 ) n -R 2 When representing a single substituent (e.g., alkyl), set n to 0 and R to... 2 Set as a substituent (alkyl).

[0309] As the aforementioned (meth)acrylic acid compound (M1), compounds represented by the following formula (b-2) or (b-3) are also preferably cited. These compounds differ from compounds that incorporate constituents having functional groups included in the above-described functional group (a) and constituents represented by the above-described formula (1-1).

[0310] [Chemical Formula 10]

[0311]

[0312] R 1 The meanings of and n are the same as those in the above formula (b-1).

[0313] R 3 With R 2 The meanings are the same.

[0314] L 2 The linking group has the same meaning as the L mentioned above. 1 same.

[0315] L 3 The linking group has the same meaning as the L mentioned above. 1 The same, but preferably alkylene groups having 1 to 6 carbon atoms (preferably 1 to 3).

[0316] m is an integer from 1 to 200, preferably an integer from 1 to 100, and more preferably an integer from 1 to 50.

[0317] In the above formulas (b-1) to (b-3), the carbon atom that forms the polymerizable group and is not bonded with R 1 The carbon atom is represented as an unsubstituted carbon atom (H₂C=), but it can have substituents. There are no particular restrictions on the substituents, but examples of substituents that can be used as R are given. 1 The above-mentioned groups.

[0318] Furthermore, in formulas (b-1) to (b-3), groups employing substituents such as alkyl, aryl, alkylene, and arylene may have substituents to a extent that does not impair the effects of the present invention. Substituents may be any substituent other than those selected from the functional group (a), for example, groups selected from substituent Z described later; specifically, halogen atoms, etc., may be included.

[0319] The (meth)acrylic acid polymer preferably has the constituent components having functional groups selected from functional group (a) or the constituent components represented by formula (1-1) above, and can have constituent components derived from (meth)acrylic acid compound (M1), constituent components derived from vinyl compound (M2), and other constituent components that can copolymerize with compounds incorporating these constituent components. From the viewpoint of dispersion stability and adhesion, it is preferable to have the constituent components represented by formula (1-1) above and the constituent components of (meth)acrylic acid compound (M1) having functional groups selected from functional group (a).

[0320] The chain polymer (constituent components and raw material compounds) may have substituents. There are no particular limitations on the substituents, but groups selected from the substituents Z above are preferred, and groups other than those included in the functional group (a) above are even more preferred.

[0321] The content of the constituent components in the (meth)acrylic acid polymer is not particularly limited and can be appropriately selected, for example, it can be set within the following range. The content of the constituent components represented by the above formula (1-1) and the constituent components having functional groups selected from functional group (a) are as described above.

[0322] The content of the component derived from (meth)acrylic acid compound (M1) in the (meth)acrylic acid polymer is not particularly limited, and can be set to 100 mol%, but is preferably 1 to 90 mol%, more preferably 10 to 80 mol%, and especially preferably 20 to 70 mol%.

[0323] The content of the constituent component derived from vinyl compound (M2) in the (meth)acrylic acid polymer is not particularly limited, but is preferably 1 to 50 mol%, more preferably 10 to 50 mol%, and especially preferably 20 to 50 mol%.

[0324] The chain polymer (each constituent component and raw material compound) may have substituents. As a substituent, there are no particular restrictions as long as it is a group other than the functional groups included in the functional group (a) above, but groups selected from the substituents Z above are preferred.

[0325] Chain polymers can be synthesized by selecting feedstock compounds using known methods and by polymerizing the feedstock compounds.

[0326] There are no particular limitations on the methods for incorporating functional groups. Examples include copolymerization of compounds having functional groups selected from group (a), methods using polymerization initiators or chain transfer agents that generate the aforementioned functional groups, methods utilizing polymer reactions, reactions of olefins in double bonds (e.g., in fluoropolymers, through defluorination of VDF components), olefin-thiol reactions, or ATRP (Atom Transfer Radical Polymerization) polymerization using copper catalysts. Furthermore, functional groups can be introduced by using functional groups present in the polymer's main chain, side chains, or ends as reaction sites. For example, by using compounds having functional groups, functional groups selected from group (a) can be introduced through various reactions with carboxylic anhydride groups in the polymer chain.

[0327] Specific examples of polymers forming polymeric adhesives A or B include those synthesized in the examples, as well as the polymers shown below; however, the invention is not limited to these. In each specific example, the number indicated to the lower right of the constituent components indicates the content of the polymer, in moles%.

[0328] [Chemical Formula 11]

[0329]

[0330] The polymers forming polymer adhesives A and B can be selected as appropriate, provided that they meet the requirements for solubility and adsorption rate. For example, the polymer forming polymer adhesive A is preferably a polymer having at least one type of bond selected from urethane bonds, urea bonds, amide bonds, imide bonds, and ester bonds in its main chain, and more preferably a polymer having urethane bonds in its main chain. The polymer forming polymer adhesive B is preferably a polymer with a carbon-carbon double bond in its main chain, and more preferably a (meth)propylene polymer. Furthermore, the combination of the polymers forming polymer adhesive A and polymer adhesive B can be suitably determined. Polymers of the same type can be used, but different types of polymers (e.g., polymers with different chemical structures in their main chains) are preferred. Specifically, combinations of preferred polymers of each polymer are preferred.

[0331] (The physical properties or characteristics of polymer adhesives A and B, or the polymers that form these adhesives)

[0332] The polymer adhesive A or B, or the polymer forming polymer adhesive A or B, preferably has the following physical properties or characteristics.

[0333] The mass-average molecular weight of the polymer forming polymeric adhesive A is not particularly limited, but is preferably 15,000 or more, more preferably 30,000 or more, and even more preferably 50,000 or more. As an upper limit, it is practically 5,000,000 or less, preferably 4,000,000 or less, more preferably 3,000,000 or less, and can also be set to 200,000 or less. On the other hand, the mass-average molecular weight of the polymer forming polymeric adhesive B is not particularly limited, but is preferably 15,000 or more, more preferably 30,000 or more, and even more preferably 50,000 or more. As an upper limit, it is practically 5,000,000 or less, preferably 4,000,000 or less, more preferably 3,000,000 or less, and can also be set to 200,000 or less.

[0334] In addition, the mass-average molecular weight of the polymer can be appropriately adjusted by changing the type and content of polymerization initiators, polymerization time, polymerization temperature, etc.

[0335] -Determination of molecular weight-

[0336] In this invention, the molecular weight of polymers, polymer chains, polymer chains, and macromonomers, unless otherwise specified, refers to the mass-average molecular weight or number-average molecular weight converted from standard polystyrene obtained by gel permeation chromatography (GPC). As a method for determination, methods set to conditions 1 or 2 (preferred) below can be cited as examples. Appropriate eluents can be selected and used according to the type of polymer, polymer chain, or macromonomer.

[0337] (Condition 1)

[0338] String: Connects 2 TOSOH TSKgel Super AWM-H (product name, manufactured by TOSOH CORPORATION)

[0339] Charge carriers: 10 mM LiBr / N-methylpyrrolidone

[0340] Measurement temperature: 40℃

[0341] Carrier flow rate: 1.0 ml / min

[0342] Sample concentration: 0.1% by mass

[0343] Detector: RI (Refractive Index) Detector

[0344] (Condition 2)

[0345] Tubes: Tubes connected to TOSOH TSKgel Super HZM-H, TOSOH TSKgel Super HZ4000, and TOSOH TSKgel Super HZ2000 (all trade names, manufactured by Tosoh Corporatio) are used.

[0346] Charge carrier: tetrahydrofuran

[0347] Measurement temperature: 40℃

[0348] Carrier flow rate: 1.0 ml / min

[0349] Sample concentration: 0.1% by mass

[0350] Detector: RI (Refractive Index) Detector

[0351] Polymer adhesives A and B do not impose any particular restrictions on the adsorption rate of the conductive additives described later. The content of the conductive additives is relatively low compared to the active material (AC) and inorganic solid electrolyte (SE), so they have little impact on the dispersion characteristics and adhesion. Therefore, the adsorption rate of the conductive additives does not need to be set within a specific range.

[0352] The moisture concentration of the polymer is preferably below 100 ppm (by mass). Furthermore, polymer binders A and B can be polymer binders used for crystallization and drying of the polymer, or they can be polymer solutions used directly.

[0353] The polymers forming polymer binders A and B are preferably amorphous. In this invention, "amorphous" typically means that no endothermic peak due to crystal melting is observed when measured at the glass transition temperature.

[0354] The polymers forming polymer binders A and B can be either non-crosslinked or crosslinked. Furthermore, when crosslinking of the polymer is achieved through heating or applying voltage, the molecular weight can become larger than the aforementioned molecular weight. Preferably, when using an all-solid-state secondary battery, the mass-average molecular weight of the polymer is within the aforementioned range.

[0355] There is no particular limitation on the total content of the polymer binder (PB) in the electrode composition, and it can be set appropriately. For example, it can be set to 0.3 to 3.0% by mass in 100% by mass of solid components.

[0356] The total content of polymer binders A and B in the electrode composition can be appropriately set according to the content of each polymer binder. From the viewpoint of balancing low resistance, dispersion characteristics and adhesion, for example, the content of 100% by mass of solid components can be set to 0.5 to 2.0% by mass, preferably 0.5 to 1.5% by mass, and more preferably 0.5 to 1.0% by mass.

[0357] There are no particular limitations on the content of polymer binder A and polymer binder B in the electrode composition, and they can be set appropriately. For example, the content of the two polymer binders A and B can be set by taking into account their dispersion characteristics and adhesion. In this case, relative to 100 parts by mass of active material (AC) or inorganic solid electrolyte (SE) contained in the electrode composition, the content can be set to 2.0 parts by mass or less, preferably 0.3 to 1.5 parts by mass, and more preferably 0.5 to 1.0 parts by mass.

[0358] In order to adsorb the active material (AC) that is usually abundant in the electrode composition, the content of polymer binder A in the electrode composition can be set to be higher than the content of polymer binder B. Specifically, from the viewpoint of balancing low resistance, dispersion characteristics (especially polymer binder A), and adhesion, the content of polymer binder B in 100% by mass is preferably 0.1 to 3.0% by mass, more preferably 0.3 to 3.0% by mass, further preferably 0.5 to 1.5% by mass, and especially preferably 0.5 to 1.0% by mass. Furthermore, specifically, from the viewpoint of balancing low resistance, dispersion characteristics (especially polymer binder B), and adhesion, the content of polymer binder B in the electrode composition is, for example, preferably 0.1 to 2.0% by mass in 100% by mass of the solid content, more preferably 0.2 to 1.5% by mass, and even more preferably 0.2 to 1.0% by mass.

[0359] The difference between the content of polymer binder A and the content of polymer binder B (content of polymer binder A - content of polymer binder B), and the ratio of the content of polymer binder A to the content of polymer binder B (content of polymer binder A / content of polymer binder B) are not particularly limited and can be appropriately set according to the content of active substance (AC) or inorganic solid electrolyte (SE).

[0360] In addition, when the electrode composition contains two or more polymer binders A or B, the above-mentioned content of polymer binders A or B shall be set as the total content.

[0361] (Other polymer adhesives)

[0362] The electrode composition of the present invention may contain one or more polymer binders other than the polymer binders A and B described above (referred to as other polymer binders). As other polymer binders, for example, considering the adsorption rate, low-adsorption binders with adsorption rates of less than 20% for both the active material (AC) and the inorganic solid electrolyte (SE) in the dispersion medium (D) can be cited; considering the solubility in the dispersion medium (D), particulate binders insoluble in the dispersion medium (D) can be cited.

[0363] As for the polymers used to form other polymer binders, various polymers used as binders for all-solid-state secondary batteries can be used without particular restrictions, as long as the adsorption rate or solubility is satisfied. Examples include the aforementioned step-growth polymers and chain polymers. As particulate binders, examples include those described in Japanese Patent Application Publication No. 2015-088486, International Publication No. 2017 / 145894, and International Publication No. 2018 / 020827. The particle size of the particulate binder (measured using the same method as for inorganic solid electrolytes) is not particularly limited, and can be set to, for example, 1 to 1000 nm.

[0364] The content of other polymer binders is not particularly limited and can be appropriately set within a range that does not impair the effect of the present invention, for example, it can be set to less than 1% by mass.

[0365] In this invention, the mass ratio of the total mass of the inorganic solid electrolyte (SE) and the active material (AC) to the total mass of the polymer binder (PB) in 100% by mass of the solid component [(mass of SE + mass of AC) / (total mass of polymer binder (PB))] is preferably in the range of 1,000 to 1. Furthermore, this ratio is more preferably 500 to 2, and even more preferably 100 to 10.

[0366] <Dispersion Medium (D)>

[0367] The electrode composition of the present invention contains a dispersion medium (D) that disperses or dissolves the above-mentioned components.

[0368] As such a dispersion medium (D), any organic compound that appears liquid in the environment of use can be used, such as various organic solvents, specifically alcohols, ethers, amides, amines, ketones, aromatics, aliphatic compounds, nitriles, esters, etc.

[0369] The dispersion medium (D) can be either a nonpolar dispersion medium (hydrophobic dispersion medium) or a polar dispersion medium (hydrophilic dispersion medium). From the viewpoint of exhibiting excellent dispersion characteristics, a nonpolar dispersion medium is preferred. A nonpolar dispersion medium generally refers to a medium with low affinity for water. In this invention, examples include ester compounds, ketone compounds, ether compounds, aromatic compounds, and aliphatic compounds.

[0370] Examples of alcohol compounds include methanol, ethanol, 1-propanol, 2-propanol, 2-butanol, ethylene glycol, propylene glycol, glycerol, 1,6-hexanediol, cyclohexanediol, sorbitol, xylitol, 2-methyl-2,4-pentanediol, 1,3-butanediol, and 1,4-butanediol.

[0371] Examples of ether compounds include alkylene glycols (diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, etc.), alkylene glycol monoalkyl ethers (ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, diethylene glycol monobutyl ether, etc.), alkylene glycol dialkyl ethers (ethylene glycol dimethyl ether, etc.), dialkyl ethers (dimethyl ether, diethyl ether, diisopropyl ether, dibutyl ether, etc.), and cyclic ethers (tetrahydrofuran, dioxanes (including 1,2-, 1,3- and 1,4- isomers, etc.)).

[0372] Examples of amide compounds include N,N-dimethylformamide, N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolinone, ε-caprolactam, formamide, N-methylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropaneamide, and hexamethylphosphoric triamide.

[0373] Examples of amine compounds include triethylamine, diisopropylethylamine, and tri-n-butylamine.

[0374] 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), isobutylpropyl ketone, sec-butylpropyl ketone, pentylpropyl ketone, butylpropyl ketone, etc.

[0375] Examples of aromatic compounds include benzene, toluene, xylene, and perfluorotoluene.

[0376] Examples of aliphatic compounds include hexane, heptane, octane, nonane, decane, dodecane, cyclohexane, methylcyclohexane, ethylcyclohexane, cycloheptane, cyclooctane, decahydronaphthalene, paraffin wax, gasoline, naphtha, kerosene, and light oil.

[0377] Examples of nitrile compounds include acetonitrile, propionitrile, and isobutyronitrile.

[0378] Examples of ester compounds include ethyl acetate, propyl acetate, butyl acetate, ethyl butyrate, propyl butyrate, isopropyl butyrate, butyl butyrate, isobutyl butyrate, butyl valerate, pentyl valerate, ethyl isobutyrate, propyl isobutyrate, isopropyl isobutyrate, isobutyl isobutyrate, propyl neovalerate, isopropyl neovalerate, butyl neovalerate, and isobutyl neovalerate.

[0379] In this invention, ether compounds, ketone compounds, aromatic compounds, aliphatic compounds, and ester compounds are preferred, and ester compounds, ketone compounds, or ether compounds are more preferred.

[0380] The number of carbon atoms in the compound constituting the dispersion medium is not particularly limited, but is preferably 2 to 30, more preferably 4 to 20, even more preferably 6 to 15, and especially preferably 7 to 12.

[0381] There is no particular limitation on the boiling point of the dispersion medium at atmospheric pressure (1 atmosphere), but it is preferably 90°C or higher, more preferably 120°C or higher. The upper limit is preferably 230°C or lower, more preferably 200°C or lower.

[0382] The dispersion medium (D) contained in the electrode composition of the present invention may be one type or two or more types.

[0383] The content of the dispersion medium (D) in the electrode composition is not particularly limited and can be appropriately set. For example, it is preferably 20-80% by mass, more preferably 30-70% by mass, and especially preferably 40-60% by mass in the electrode composition.

[0384] <Conductive Additive (CA)>

[0385] The electrode composition of the present invention preferably contains a conductive additive (CA).

[0386] There are no particular restrictions on the conductive additives used; any conductive additives known to be used as conductive additives can be used. For example, they can be graphite materials such as natural graphite and artificial graphite, carbon black such as acetylene black, Ketjen black, and furnace black, amorphous carbon such as needle coke, carbon fiber materials such as vapor-grown carbon fibers or carbon nanotubes, carbonaceous materials such as graphene or fullerene, metal powders such as copper and nickel, metal fibers, or conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene, and polyphenylene derivatives.

[0387] In this invention, when using an active material and a conductive additive in combination, the conductive additive used is one that, during battery charging and discharging, does not generate the insertion and extraction of metal ions (preferably Li ions) belonging to Group 1 or Group 2 of the periodic table, and does not function as an active material. Therefore, among the conductive additives, those that function as active materials in the active material layer during battery charging and discharging are classified as active materials rather than conductive additives. Whether or not an active material functions during battery charging and discharging is determined by its combination with the active material, rather than by a general rule.

[0388] The conductive additive contained in the electrode composition of the present invention is preferably in particulate form. The shape of the particles is not particularly limited and can be flat, amorphous, etc., but is preferably spherical or granular. When the conductive additive is in particulate form, the particle size (volume average particle size) is not particularly limited; for example, it is preferably 0.02 to 1.0 μm, more preferably 0.03 to 0.5 μm. The particle size of the conductive additive can be adjusted in the same way as the particle size of the inorganic solid electrolyte described above, and its measurement method can also be the same as that for the inorganic solid electrolyte.

[0389] The electrode composition of the present invention may contain one or more conductive additives.

[0390] The content of the conductive additive in the electrode composition is not particularly limited and can be appropriately determined. For example, it is preferably 10% by mass or less, and more preferably 1.0 to 5.0% by mass, out of 100% by mass of the solid content.

[0391] <Lithium Salts>

[0392] The electrode composition of the present invention may also contain a lithium salt (supporting electrolyte). As the lithium salt, a lithium salt commonly used in this type of product is preferred, without particular limitation; for example, the lithium salt described in paragraphs 0082 to 0085 of Japanese Patent Application Publication No. 2015-088486 is preferred. When the electrode composition of the present invention contains a lithium salt, the content of the lithium salt relative to 100 parts by weight of the inorganic solid electrolyte is preferably 0.1 parts by weight or more, more preferably 5 parts by weight or more. As an upper limit, it is preferably 50 parts by weight or less, more preferably 20 parts by weight or less.

[0393] <Dispersant>

[0394] In the electrode composition of the present invention, since the aforementioned polymer binder (PB), especially polymer binders A and B, also function as dispersants, it is possible to omit dispersants other than polymer binder (PB). When the electrode composition contains dispersants other than polymer binder (PB), dispersants commonly used in all-solid-state secondary batteries can be appropriately selected as the dispersant. Typically, compounds intended for particle adsorption, steric repulsion, and / or electrostatic repulsion are appropriately used.

[0395] <Other Additives>

[0396] The electrode composition of the present invention can appropriately contain ionic liquids, thickeners, crosslinking agents (substances that undergo crosslinking reactions via free radical polymerization, condensation polymerization, or ring-opening polymerization, etc.), polymerization initiators (substances that generate acids or free radicals through heat or light, etc.), defoamers, homogenizers, dehydrating agents, antioxidants, etc., as other components besides the aforementioned components. The ionic liquid is a liquid contained to further improve ionic conductivity, and known liquids can be used without particular limitation.

[0397] (Preparation of electrode composition)

[0398] The electrode composition of the present invention can be prepared by conventional methods. For example, it can be prepared into a mixture, preferably into a slurry, by mixing an inorganic solid electrolyte (SE), an active material (AC), a polymer binder (PB), and a dispersion medium (D), as well as a suitable conductive additive (CA), a lithium salt, and any other components, using various commonly used mixers.

[0399] There are no particular restrictions on the mixing method of the above components; they can be mixed together or mixed sequentially. The adsorption rates A of polymer adhesives A and B are... AC and A SEWhen the difference is large, from the viewpoint of work efficiency, a combined mixing method is preferred. In this invention, the electrode composition is preferably prepared by mixing the above-mentioned components through a method for preparing the electrode composition of this invention having the following steps. By this method, polymer binder A can be preferentially adsorbed onto the active material (AC), and polymer binder B can be preferentially adsorbed onto the inorganic solid electrolyte (SE). As a result, the dispersion characteristics and adhesion of the active material (AC) and the inorganic solid electrolyte (SE) can be further improved.

[0400] Preparation process of active substance composition:

[0401] The process for preparing an active substance composition containing active substance (AC), polymer binder A, and dispersion medium (D)

[0402] Preparation process of solid electrolyte composition:

[0403] The process for preparing a solid electrolyte composition containing an inorganic solid electrolyte (SE), a polymer binder B, and a dispersion medium (D).

[0404] Electrode composition preparation process:

[0405] The process of mixing the prepared active substance composition and the solid electrolyte composition

[0406] -Preparation process of active substance composition-

[0407] In the active material composition preparation step, the active material (AC), polymer binder A, and dispersion medium (D) are (pre-mixed) to prepare the active material composition. This step allows polymer binder A to preferentially adsorb onto the active material (AC) (avoiding adsorption with the inorganic solid electrolyte (SE), resulting in a mixture (slurry) in which the active material (AC) is adsorbed (bonded) by polymer binder A. In this step, to improve the preferential adsorption of polymer binder A onto the active material (AC), it is preferable to mix the materials in the absence of the inorganic solid electrolyte (SE) and / or polymer binder B. Here, "absent" includes the following: without impairing the effects of the present invention, the inorganic solid electrolyte (SE) and polymer binder B are each present, for example, in a content of 5% by mass or less relative to the solid content of the electrode composition.

[0408] In this process, the amount of each component used can be appropriately set considering the content of each component in the target electrode composition. Typically, the mixing amount (content) of the active material (AC) and the polymer binder A is set within the same range as the content of each component in the electrode composition per 100% by mass of solids. That is, there is no particular limitation on the mixing ratio of the active material (AC) to the polymer binder A; however, from the viewpoint of work efficiency, it is generally preferred to set it to the mixing ratio of the active material (AC) to the polymer binder A in the electrode composition.

[0409] The amount of dispersion medium (D) used can be appropriately set considering the content of dispersion medium (D) in the electrode composition, the amount of dispersion medium (D) used in the solid electrolyte composition preparation process, etc., but it is preferable to set it to the amount used to dissolve the polymer binder A. For example, considering the concentration of the solid component in the obtained active material composition, it can be set to 20-85% by mass, preferably 40-80% by mass. On the other hand, considering the content of dispersion medium (D) in the electrode composition, when its content is set to 100% by mass, it can be set to 0.1-70% by mass, preferably 0.5-60% by mass.

[0410] There are no particular limitations on the mixing method and conditions in this process; they can be set appropriately.

[0411] For example, the mixing order of the components can be either all together or sequentially. Furthermore, the mixing method can utilize known mixers such as ball mills, bead mills, planetary mixers, scraper mixers, roller mills, kneaders, disc mills, rotation-revolution mixers, and narrow-gap dispersers. As for mixing conditions, for example, a mixing temperature of 10–60°C can be used, with the rotation speed of the rotation-revolution mixer set to 10–700 rpm (rotation per minute) and the mixing time set to 5 minutes to 5 hours. When using a ball mill as the mixer, within the aforementioned mixing temperature range, it is preferable to set the rotation speed to 50–700 rpm and the mixing time to 5 minutes to 24 hours, preferably 5–60 minutes.

[0412] The mixing atmosphere can be any atmosphere, including atmospheric pressure, dry air (dew point below -20°C), and inert gases (e.g., argon, helium, nitrogen). Since inorganic solid electrolytes readily react with moisture, mixing under dry air or an inert gas is preferred.

[0413] In addition, the mixing in this process can be carried out in multiple stages.

[0414] -Preparation process of solid electrolyte composition-

[0415] In the solid electrolyte composition preparation process, an inorganic solid electrolyte (SE), a polymer binder B, and a dispersion medium (D) are (pre-mixed) to prepare the inorganic solid electrolyte composition. This process allows the polymer binder B to preferentially adsorb onto the inorganic solid electrolyte (SE) (avoiding adsorption onto the active material (AC), resulting in a mixture (slurry) in which the inorganic solid electrolyte (SE) is adsorbed (bonded) by the polymer binder B. In this process, to improve the preferential adsorption of the polymer binder B onto the inorganic solid electrolyte (SE), it is preferable to mix the mixture in the absence of the active material (AC) and / or the polymer binder A. Here, "absent" includes the presence of the active material (AC) and the polymer binder A, for example, at a content of 10% by mass or less relative to the solid content of the electrode composition, without impairing the effects of the present invention.

[0416] In this process, the amount of each component used can be appropriately set considering the content of each component in the target electrode composition. Typically, the mixing amount (content) of the inorganic solid electrolyte (SE) and the polymer binder B is set within the same range as the content of each component in the electrode composition within 100% by mass of the solid components. That is, there is no particular limitation on the mixing ratio of the inorganic solid electrolyte (SE) to the polymer binder B; however, from the viewpoint of work efficiency, it is generally preferred to set it to a certain mixing ratio of the inorganic solid electrolyte (SE) to the polymer binder B in the electrode composition.

[0417] The amount of dispersion medium (D) used can be appropriately set considering the content of dispersion medium (D) in the electrode composition, the amount of dispersion medium (D) used in the preparation step of the active material composition, etc., but it is preferable to set it to the amount used to dissolve the polymer binder B. For example, considering the solid component concentration of the obtained electrolyte composition, it can be set to 20-85% by mass, preferably 40-80% by mass. On the other hand, considering the content of dispersion medium (D) in the electrode composition, when its content is set to 100% by mass, it can be set to 0.1-70% by mass, preferably 0.5-60% by mass. The amount of dispersion medium (D) used is preferably set so that the total amount used in the preparation step of the active material composition and the preparation step of the solid electrolyte composition is in the same range as the content of dispersion medium (D) in the electrode composition.

[0418] There are no particular restrictions on the mixing methods and conditions in this process; they can be appropriately set. For example, the mixing methods and conditions used in the preparation process of the active substance composition can be applied. Furthermore, the mixing methods and conditions used in this process can be the same as or different from those used in the preparation process of the active substance composition.

[0419] -Electrode composition preparation process-

[0420] In the method for preparing the electrode composition of the present invention, the active material composition and the solid electrolyte composition obtained in the above-described steps are mixed to prepare the electrode composition. This maintains the adsorption state between the active material (AC) and the polymer binder A in the active material composition, and the adsorption state between the inorganic solid electrolyte (SE) and the polymer binder B in the solid electrolyte composition, while simultaneously ensuring that each component is highly dispersed in the dispersion medium (D).

[0421] In this process, there are no particular restrictions on the mixing ratio of the active material composition and the solid electrolyte composition, but it is preferable to mix them in the same proportion as each of the active material (AC), inorganic solid electrolyte (SE), polymer binder A, and polymer binder B in the electrode composition. Furthermore, regarding the dispersion medium (D), it is possible to add an amount that is insufficient relative to the content in the electrode composition, or to concentrate an excess amount, in this process.

[0422] There are no particular restrictions on the mixing methods and conditions in this process; they can be appropriately set. For example, the mixing methods and conditions used in the active substance composition preparation process can be applied. Furthermore, the mixing methods and conditions used in this process can be the same as or different from those used in the active substance composition preparation process or the solid electrolyte composition preparation process.

[0423] In the method for preparing the electrode composition of the present invention, in the active material composition obtained in the active material composition preparation step and the solid electrolyte composition obtained in the solid electrolyte composition preparation step, the active material (AC) or inorganic solid electrolyte (SE) is adsorbed onto polymer binder A or polymer binder B and dispersed in the dispersion medium (D). Therefore, the electrode composition preparation step does not need to be carried out immediately after the completion of the above two composition preparation steps, and can also be carried out at intervals within a range that does not impair the dispersibility of the two compositions.

[0424] In the preparation method of the electrode composition of the present invention, conductive additives (CA), lithium salts, dispersants, and other additives can be mixed in any step. From the viewpoint of not hindering the preferred adsorption of the active material (AC) or inorganic solid electrolyte (SE) with polymer binder A or polymer binder B, these components are preferably mixed in the electrode composition preparation step. The mixing amount of these components is generally preferably set within the same range as their content in the electrode composition.

[0425] Electrode sheets for all-solid-state rechargeable batteries

[0426] The electrode sheet for all-solid-state secondary batteries of the present invention (sometimes simply referred to as electrode sheet) is a sheet-shaped molded body capable of forming an active material layer or electrode (a laminate of an active material layer and a current collector) for all-solid-state secondary batteries, and includes various forms depending on its application.

[0427] The electrode sheet of the present invention can be any electrode sheet having an active material layer composed of the electrode composition of the present invention described above. It can be a sheet in which the active material layer is formed on a substrate (current collector), or it can be a sheet formed of an active material layer without a substrate. The electrode sheet is generally a sheet having a substrate (current collector) and an active material layer, but it also includes forms having a substrate (current collector), an active material layer and a solid electrolyte layer in sequence, and forms having a substrate (current collector), an active material layer, a solid electrolyte layer and an active material layer in sequence.

[0428] Furthermore, the electrode sheet may have other layers besides those mentioned above. Examples of other layers include protective layers (release sheets) and coatings.

[0429] As for the substrate, there are no particular limitations as long as it is a substrate capable of supporting the active material layer. Examples include the materials described in the current collector section, organic materials, inorganic materials, and sheet-like (plate-like) materials. Examples of organic materials include various polymers, specifically polyethylene terephthalate, polypropylene, polyethylene, and cellulose. Examples of inorganic materials include, for example, glass and ceramics.

[0430] At least one of the active material layers of the electrode sheet is formed from the electrode composition of the present invention. The content of each component in the active material layer formed from the electrode composition of the present invention is not particularly limited, but preferably has the same meaning as the content of each component in the solid components of the electrode composition 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 described later in the description of all-solid-state secondary batteries.

[0431] In this invention, each layer constituting the sheet for all-solid-state secondary batteries can be a single-layer structure or a multi-layer structure.

[0432] In addition, when the solid electrolyte layer or active material layer is not formed by the electrode composition of the present invention, it is formed by a conventional constituent layer forming material.

[0433] In the electrode sheet of the present invention, the active material layer is formed by the electrode composition of the present invention and has a low-resistance active material layer formed by firmly bonding solid particles together. Therefore, the electrode sheet for all-solid-state secondary batteries of the present invention serves as the active material layer of an all-solid-state secondary battery, thereby enabling the realization of an all-solid-state secondary battery with low resistance and exhibiting excellent rate characteristics. In particular, in the electrode sheet for all-solid-state secondary batteries where the active material layer is formed on the current collector, the active material layer and the current collector exhibit strong adhesion, enabling further improvement in rate characteristics. Thus, the electrode sheet for all-solid-state secondary batteries of the present invention is suitable as a sheet-like component for forming the active material layer of an all-solid-state secondary battery, and preferably forming an electrode (assembled as an active material layer or an electrode).

[0434] [Manufacturing method of electrode sheets for all-solid-state secondary batteries]

[0435] The manufacturing method of the electrode sheet for all-solid-state secondary batteries of the present invention is not particularly limited. It can be manufactured by forming an active material layer using the electrode composition of the present invention, preferably using the electrode composition prepared by the preparation method of the electrode composition of the present invention. For example, a method can be described by forming a film (coating and drying) of the electrode composition of the present invention on the surface of a substrate (which may be via other layers) to form a layer (coating and drying layer) composed of the electrode composition. Thus, an electrode sheet for all-solid-state secondary batteries having a substrate and a coating and drying layer can be manufactured. In particular, if a current collector is used as the substrate, the adhesion between the current collector and the active material layer (coating and drying layer) can be made stronger. Here, the coating and drying layer refers to a layer formed by coating the electrode composition of the present invention and drying the dispersion medium (i.e., a layer formed using the electrode composition of the present invention and composed of a composition from which the dispersion medium has been removed from the electrode composition of the present invention). Within the scope of not impairing the effects of the present invention, the dispersion medium may remain in the active material layer and the coating and drying layer. As a residual amount, for example, it can be set to 3% by mass or less in the coating and drying layer.

[0436] In the manufacturing method of the electrode sheet for all-solid-state secondary battery of the present invention, each step such as coating and drying will be described in the following manufacturing method of all-solid-state secondary battery.

[0437] In this way, it is possible to manufacture electrode sheets for all-solid-state secondary batteries having an active material layer consisting of a coated and dried layer, or an active material layer formed by appropriately pressurizing the coated and dried layer. The pressurization conditions, etc., will be explained in the manufacturing method of all-solid-state secondary batteries described later.

[0438] Furthermore, in the manufacturing method of the electrode sheet for all-solid-state secondary batteries of the present invention, it is also possible to peel off the substrate, protective layer (especially the release sheet), etc.

[0439] [All-solid-state rechargeable battery]

[0440] The all-solid-state secondary battery of the present invention comprises a positive electrode active material layer, a negative electrode active material layer opposite to the positive electrode active material layer, and a solid electrolyte layer disposed between the positive electrode active material layer and the negative electrode active material layer. The all-solid-state secondary battery of the present invention is only required to have a structure with a solid electrolyte layer between the positive electrode active material layer and the negative electrode active material layer; other structures are not particularly limited, for example, known structures related to all-solid-state secondary batteries can be used. In a preferred all-solid-state secondary battery, a positive electrode current collector is stacked on the surface of the positive electrode active material layer opposite to the solid electrolyte layer to form a positive electrode, and a negative electrode current collector is stacked on the surface of the negative electrode active material layer opposite to the solid electrolyte layer to form a negative electrode. In the present invention, each constituent layer (including the current collector, etc.) constituting the all-solid-state secondary battery can be a single-layer structure or a multi-layer structure.

[0441] At least one of the negative electrode active material layer and the positive electrode active material layer of the all-solid-state secondary battery of the present invention is formed by the electrode composition of the present invention, preferably at least the positive electrode active material layer is formed by the electrode composition of the present invention. Furthermore, it is also preferred that both the negative electrode active material layer and the positive electrode active material layer are formed by the electrode composition of the present invention. Furthermore, for the negative electrode (a stack of negative electrode current collectors) and the positive electrode (a stack of positive electrode current collectors), it is preferred that either one, and preferably the positive electrode, is formed by the electrode sheet for the all-solid-state secondary battery of the present invention; it is also preferred that both are formed by the electrode sheet for the all-solid-state secondary battery of the present invention. In the present invention, the active material layer of the all-solid-state secondary battery formed by the electrode composition of the present invention includes a method of forming a constituent layer by the electrode sheet for the all-solid-state secondary battery of the present invention (wherein, a sheet obtained by removing layers other than the active material layer formed by the electrode composition of the present invention).

[0442] The active material layer formed by the electrode composition of the present invention preferably contains the same types and amounts of components as those in the solid components of the electrode composition of the present invention.

[0443] In addition, when the active material layer is not formed by the electrode composition of the present invention, the active material layer and the solid electrolyte layer can be made using known materials.

[0444] In this invention, each constituent layer (including current collectors, etc.) constituting the all-solid-state secondary battery can be a single-layer structure or a multi-layer structure.

[0445] <Positive electrode active material layer and negative electrode active material layer>

[0446] There is no particular limitation on the thickness of the negative electrode active material layer and the positive electrode active material layer. Considering the size of a typical all-solid-state secondary battery, the thickness of each layer is preferably 10 to 1,000 μm, more preferably 20 μm or more and less than 500 μm. In the all-solid-state secondary battery of the present invention, the thickness of at least one of the positive electrode active material layer and the negative electrode active material layer is further preferably 50 μm or more and less than 500 μm.

[0447] <Solid Electrolyte Layer>

[0448] The solid electrolyte layer is formed using a known material capable of forming a solid electrolyte layer for an all-solid-state secondary battery. Its thickness is not particularly limited, but is preferably 10 to 1,000 μm, more preferably 20 μm or more and less than 500 μm.

[0449] <Current Collector>

[0450] The positive electrode active material layer and the negative electrode active material layer preferably each have a current collector on the side opposite to the solid electrolyte layer. Such positive electrode current collectors and negative electrode current collectors are preferably electron conductors.

[0451] In this invention, either the positive current collector or the negative current collector, or both together, are sometimes referred to simply as the current collector.

[0452] In addition to aluminum, aluminum alloys, stainless steel, nickel, and titanium, materials in which carbon, nickel, titanium, or silver (materials with thin films) are treated on the surface of aluminum or stainless steel are preferred as the material forming the positive current collector. Among these, aluminum and aluminum alloys are more preferred.

[0453] In addition to aluminum, copper, copper alloys, stainless steel, nickel, and titanium, materials that have been treated with carbon, nickel, titanium, or silver on the surface of aluminum, copper, copper alloys, or stainless steel are preferred as materials for forming the negative current collector. More preferably, aluminum, copper, copper alloys, and stainless steel are preferred.

[0454] Current collectors are typically shaped like films, but can also be made of mesh, perforated material, lath material, porous material, foam material, or fiber assembly.

[0455] The thickness of the current collector is not particularly limited, but is preferably 1 to 500 μm. Furthermore, it is also preferable to have irregularities formed on the surface of the current collector through surface treatment.

[0456] <Other Structures>

[0457] In this invention, functional layers or components may be appropriately inserted or disposed between or on the outside of the layers of the negative electrode current collector, the negative electrode active material layer, the solid electrolyte layer, the positive electrode active material layer, and the positive electrode current collector.

[0458] <Frame>

[0459] The all-solid-state secondary battery of the present invention can be used directly as an all-solid-state secondary battery depending on the application, but in order to make it into a dry cell form, it is preferable to further encapsulate it in a suitable casing. The casing can be a metallic casing or a resin (plastic) casing. When using a metallic casing, for example, a casing made of aluminum alloy or stainless steel can be used. It is preferable to divide the metallic casing into a positive electrode side casing and a negative electrode side casing, which are electrically connected to the positive electrode current collector and the negative electrode current collector, respectively. It is preferable that the positive electrode side casing and the negative electrode side casing are joined and integrated with each other through a short-circuit prevention gasket.

[0460] The following is for reference. Figure 1 The preferred embodiments of the present invention will be described, but the present invention is not limited thereto.

[0461] Figure 1 This is a schematic cross-sectional view illustrating a preferred embodiment of the all-solid-state secondary battery (lithium-ion secondary battery) of the present invention. Viewed from the negative electrode side, the all-solid-state secondary battery 10 of this embodiment sequentially comprises a negative electrode current collector 1, a negative electrode active material layer 2, a solid electrolyte layer 3, a positive electrode active material layer 4, and a positive electrode current collector 5. Each layer is in contact with the others and has an adjacent structure. By employing such a structure, during charging, electrons (e... - ) is supplied to the negative electrode side, and lithium ions (Li) + Lithium ions (Li) accumulate here. On the other hand, during discharge, lithium ions (Li) accumulated at the negative electrode... + The electrons return to the positive side and supply electrons to the working part 6. In the illustrated example, a light bulb is used as a model in the working part 6, and the bulb is lit by discharging.

[0462] In having Figure 1 When the layered solid-state secondary battery shown is placed in a 2032-type button cell, the solid-state secondary battery is sometimes referred to as a laminate for solid-state secondary batteries. The battery made by placing the laminate for solid-state secondary batteries in a 2032-type button cell is called a (button-type) solid-state secondary battery.

[0463] (Solid electrolyte layer)

[0464] The solid electrolyte layer can use materials that have been used in conventional all-solid-state secondary batteries without particular restrictions. This solid electrolyte layer contains an inorganic solid electrolyte with conductivity ions of metals belonging to Group 1 or Group 2 of the periodic table, and appropriate of the aforementioned components, but typically does not contain active materials.

[0465] (Positive electrode active material layer and negative electrode active material layer)

[0466] In the all-solid-state secondary battery 10, both the positive electrode active material layer and the negative electrode active material layer are formed from the electrode composition of the present invention. Preferably, the positive electrode, which is formed by stacking the positive electrode active material layer and the positive electrode current collector, and the negative electrode, which is formed by stacking the negative electrode active material layer and the negative electrode current collector, are formed from the electrode sheet of the present invention using the current collector as a substrate.

[0467] The positive electrode active material layer contains an inorganic solid electrolyte with conductivity of ions belonging to Group 1 or Group 2 of the periodic table, a positive electrode active material, polymer binders A and B, and any of the above-mentioned components within the scope that does not impair the effects of the present invention.

[0468] The negative electrode active material layer contains an inorganic solid electrolyte having conductive ions of metals belonging to Group 1 or Group 2 of the periodic table, a negative electrode active material, polymer binders A and B, and any of the above-mentioned components within the range that does not impair the effects of the present invention. In the all-solid-state secondary battery 10, the negative electrode active material layer can be a lithium metal layer. Examples of lithium metal layers include layers formed by stacking or molding lithium metal powder, lithium foil, and lithium vapor-deposited films. The thickness of the lithium metal layer is independent of the aforementioned thickness of the negative electrode active material layer, and for example, can be set to 1 to 500 μm.

[0469] The components contained in the positive electrode active material layer 4, the solid electrolyte layer 3, and the negative electrode active material layer 2, especially the inorganic solid electrolyte, conductive additives, and polymer binders, can be of the same type or different types.

[0470] In this invention, if the active material layer is formed from the electrode composition of this invention, an all-solid-state secondary battery with low resistance and excellent rate characteristics can be realized.

[0471] (Current collector)

[0472] The positive current collector 5 and the negative current collector 1 are as described above.

[0473] In the all-solid-state secondary battery 10 described above, when it has a constituent layer other than the constituent layer formed by the electrode composition of the present invention, a layer formed by a known constituent layer forming material can also be applied.

[0474] Furthermore, each layer can be a single layer or multiple layers.

[0475] [Manufacturing of all-solid-state rechargeable batteries]

[0476] All-solid-state secondary batteries can be manufactured using conventional methods. Specifically, all-solid-state secondary batteries can be manufactured by forming at least one active material layer using the electrode composition of the present invention, and forming a solid electrolyte layer, another suitable active material layer, or an electrode using known materials.

[0477] The all-solid-state secondary battery of the present invention can be manufactured by performing a method including the following steps: applying the electrode composition of the present invention appropriately to the surface of a substrate (e.g., a metal foil that serves as a current collector) and drying it to form a coating film (film forming) (method for manufacturing electrode sheet for all-solid-state secondary battery of the present invention).

[0478] For example, a positive electrode active material layer is formed by coating an electrode composition containing a positive electrode active material onto a metal foil serving as the positive electrode current collector, thereby creating a positive electrode sheet for an all-solid-state secondary battery. Next, a composition containing an inorganic solid electrolyte is coated onto this positive electrode active material layer to form a solid electrolyte layer. Furthermore, a negative electrode active material layer is formed by coating an electrode composition containing a negative electrode active material onto the solid electrolyte layer, serving as the negative electrode material (negative electrode composition). By stacking a negative electrode current collector (metal foil) onto the negative electrode active material layer, an all-solid-state secondary battery with a structure where the solid electrolyte layer is sandwiched between the positive and negative electrode active material layers can be obtained. This can also be encapsulated in a casing to manufacture a desired all-solid-state secondary battery.

[0479] Furthermore, in contrast to the methods for forming each layer, it is also possible to manufacture an all-solid-state secondary battery 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 stacking the positive electrode current collector.

[0480] As another method, the following approach can be used: The positive electrode sheet for an all-solid-state secondary battery is manufactured as described above. Furthermore, an electrode composition containing a negative electrode active material is coated onto a metal foil serving as the negative electrode current collector to form a negative electrode active material layer, thereby manufacturing an all-solid-state secondary battery negative electrode sheet. Next, a solid electrolyte layer is formed on the active material layer of any one of these sheets, as described above. Then, the other of the all-solid-state secondary battery positive electrode sheet and the all-solid-state secondary battery negative electrode sheet is stacked on the solid electrolyte layer in such a way that the solid electrolyte layer and the active material layer are in contact. In this way, an all-solid-state secondary battery can be manufactured.

[0481] Furthermore, as another method, the following can be cited: That is, to manufacture the positive electrode sheet and the negative electrode sheet for an all-solid-state secondary battery as described above. In addition, a solid electrolyte sheet for an all-solid-state secondary battery, consisting of a solid electrolyte layer, is manufactured by coating a composition containing an inorganic solid electrolyte onto a substrate. Moreover, the solid electrolyte layer, peeled off from the substrate, is stacked by sandwiching the positive electrode sheet and the negative electrode sheet for an all-solid-state secondary battery. In this way, an all-solid-state secondary battery can be manufactured.

[0482] Furthermore, as described above, a positive electrode sheet 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 manufactured. Next, the positive electrode sheet or a negative electrode sheet for an all-solid-state secondary battery and the solid electrolyte sheet for an all-solid-state secondary battery are laminated together to a state where the positive or negative active material layer is in contact with the solid electrolyte layer, and pressure is applied. This transfers the solid electrolyte layer onto the positive or negative electrode sheet for an all-solid-state secondary battery. Then, the solid electrolyte layer obtained by peeling off the substrate of the solid electrolyte sheet for an all-solid-state secondary battery and the negative or positive electrode sheet for an all-solid-state secondary battery (with the negative or positive active material layer in contact with the solid electrolyte layer) are laminated together and pressure is applied. This allows the manufacture of an all-solid-state secondary battery. There are no particular limitations on the pressure application method and conditions in this method; the methods and conditions described in the later pressure application steps can be used.

[0483] The active material layer can also be formed by, for example, pressing an electrode composition on a substrate or active material layer under pressure conditions described later, and a sheet-formed active material can also be used.

[0484] In the above manufacturing method, the electrode composition of the present invention can be used in either the positive electrode composition or the negative electrode composition. Both the positive electrode composition and the negative electrode composition can use the electrode composition of the present invention.

[0485] When an active material layer is formed from a composition other than the electrode composition of the present invention, commonly used compositions and the like can be cited as materials. Furthermore, it is also possible to form a negative electrode active material layer without forming a negative electrode active material layer during the manufacture of an all-solid-state secondary battery, by combining ions and electrons of a metal belonging to Group I or Group II of the periodic table that has accumulated in the negative electrode current collector during initialization or charging as described later, and depositing it as metal on the negative electrode current collector, thereby forming a negative electrode active material layer.

[0486] <Formation of each layer (film formation)>

[0487] There are no particular limitations on the coating method for each composition, and it can be appropriately selected. Examples of wet coating methods include coating (preferably wet coating), spraying, spin coating, dip coating, slot coating, strip coating, and bar coating.

[0488] It is preferable to perform a drying treatment (heat treatment) on the coated composition. The drying treatment can be performed after each coating of the composition or after multiple coatings. The drying temperature is not particularly limited as long as it is sufficient to remove the dispersion medium, and is appropriately set according to the boiling point of the dispersion medium, etc. For example, the lower limit of the drying temperature 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. By heating within this temperature range, the dispersion medium can be removed to obtain a solid state (coated dried layer). Furthermore, it avoids excessively high temperatures and damage to the components of the all-solid-state secondary battery, which is therefore preferable. As a result, the all-solid-state secondary battery exhibits excellent overall performance and achieves good coating adaptability (adhesion) and good ion conductivity even without pressure.

[0489] As described above, when the electrode composition of the present invention is coated and dried, deviations in the contact state can be suppressed and solid particles can be firmly bonded, thereby forming a low-resistance coated and dried layer.

[0490] After coating each composition, and after laminating to form layers, or after fabricating an all-solid-state secondary battery, each layer or the all-solid-state secondary battery is pressurized. Examples of pressurization methods include hydraulic cylinder presses. There are no particular limitations on the pressurization pressure, but a range of 5 to 1500 MPa is generally preferred.

[0491] Furthermore, the coated compositions can be heated simultaneously with pressure. There are no particular limitations on the heating temperature, which is typically in the range of 30–300°C. Stamping can also be performed at temperatures higher than the glass transition temperature of the inorganic solid electrolyte. Additionally, stamping can be performed at temperatures higher than the glass transition temperature of the polymer constituting the polymer binder. However, the temperature is typically no higher than the melting point of the polymer.

[0492] Pressurization can be performed either with the solvent or dispersion medium pre-dried or with residual solvent or dispersion medium remaining.

[0493] Alternatively, the various compositions can be coated simultaneously, or the coating, drying, and stamping can be performed simultaneously and / or sequentially. They can be laminated by transfer printing after being coated onto their respective substrates.

[0494] There are no particular limitations on the atmosphere used in film-forming methods (coating, drying, pressurization (under heating)). It can be any environment, such as atmospheric pressure, dry air (dew point below -20°C), or inert gases (e.g., argon, helium, nitrogen).

[0495] The stamping time can be either a short period of time (e.g., within a few hours) to apply high pressure, or a long period of time (more than one day) to apply medium pressure. In addition to electrode sheets for all-solid-state secondary batteries, for example in the case of all-solid-state secondary batteries, it is possible to use the constraint tools of all-solid-state secondary batteries (screw tightening pressure, etc.) to continuously apply medium pressure.

[0496] Compared to the pressure-bearing parts such as the surface of the sheet, the stamping pressure can be uniform or varying.

[0497] The stamping pressure can be varied according to the area or film thickness of the pressed part. Furthermore, it is also possible to apply different pressures to the same part in stages.

[0498] The stamped surface can be smooth or rough.

[0499] <Initialization>

[0500] All-solid-state secondary batteries manufactured in the manner described above are preferably initialized after manufacturing or before use. Initialization is not particularly limited, and for example, it can be performed as follows: initial charge and discharge are carried out under increased stamping pressure, and then the pressure is released until the normal operating pressure of the all-solid-state secondary battery is reached.

[0501] Applications of all-solid-state rechargeable batteries

[0502] The all-solid-state secondary battery of this invention can be applied to a wide variety of uses. There are no particular limitations on its application; for example, when integrated into electronic devices, it can be used in laptops, pen-and-paper computers, mobile computers, e-book readers, mobile phones, cordless phones, pagers, handheld terminals, portable fax machines, portable copiers, portable printers, stereo headphones, camcorders, LCD TVs, handheld vacuum cleaners, portable CD players, mini disk drives, electric shavers, transceivers, electronic notebooks, calculators, memory cards, portable recorders, radios, backup power supplies, etc. As other civilian products, it can be used in automobiles (electric vehicles), electric vehicles, motors, lighting fixtures, toys, game consoles, load conditioners, clocks, flashlights, cameras, and medical devices (pacemakers, hearing aids, and shoulder massagers, etc.). Furthermore, it can be used in various military and aerospace products. It can also be combined with solar cells.

[0503] Example

[0504] The present invention will now be described in further detail with reference to embodiments, but the invention should not be construed as limiting. In the following embodiments, unless otherwise specified, "parts" and "%" of composition refer to mass. In the present invention, "room temperature" refers to 25°C.

[0505] 1. Polymer Synthesis

[0506] Polymers S1 to S15, as shown in the following chemical formulas, were synthesized as follows.

[0507] [Synthesis Example S1: Synthesis of Polymer S1 and Preparation of Adhesive Solution S1]

[0508] 46.1 g of NISSO-PB GI-3000 (trade name, manufactured by Nippon Soda Co., Ltd.) was added to a 200 mL three-necked flask and dissolved in 64 g of butyl butyrate (manufactured by Tokyo Chemical Industry Co., Ltd.). 3.9 g of dicyclohexylmethane-4,4'-diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to this solution and stirred at 80 °C until homogeneous. 0.1 g of NEOSTANN U-600 (trade name, manufactured by NITTOHCHEMICAL Co., Ltd.) was added to the obtained solution and stirred at 80 °C for 10 hours to synthesize polymer S1 (polyurethane), thus obtaining solution S1 (concentration 40% by mass) of a polymer binder composed of polymer S1.

[0509] [Synthesis Example S2: Synthesis of Polymer S2 and Preparation of Adhesive Solution S2]

[0510] In Synthesis Example S1, compounds that introduce each constituent component are used to make polymer S2 have the composition shown in Table 1 (types and amounts of constituent components). Otherwise, polymer S2 (polyurethane) is synthesized in the same manner as in Synthesis Example S1, and a solution S2 of polymer adhesive composed of polymer S2 is obtained.

[0511] [Synthesis Example S3: Synthesis of Polymer S3 and Preparation of Adhesive Solution S3]

[0512] A monomer solution was prepared by adding 2.9 g of 2-hydroxyethyl acrylate (manufactured by FUJIFILM Wako Pure Chemical Corporation), 19.1 g of dodecyl methacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), and 0.3 g of polymerization initiator V-601 (trade name, manufactured by FUJIFILM Wako Pure Chemical Corporation) to a 100 mL volumetric flask and dissolving them in 36 g of butyl butyrate. Next, 12 g of butyl butyrate was added to a 300 mL three-necked flask, and after stirring at 80 °C, the monomer solution was added dropwise over 2 hours. After the addition was complete, the temperature was raised to 90 °C, and the mixture was stirred for 2 hours to synthesize polymer S3 (acrylic polymer), obtaining a polymer binder solution S3 (concentration 30% by mass) composed of polymer S3.

[0513] [Synthesis Example S4: Synthesis of Polymer S4 and Preparation of Adhesive Solution S4]

[0514] In Synthesis Example S3, compounds that introduce each constituent component were used to make polymer S4 have the composition shown in Table 1 (types and amounts of constituent components). Otherwise, polymer S4 (acrylic polymer) was synthesized in the same manner as in Synthesis Example S3, and a solution S4 of polymer adhesive composed of polymer S4 was obtained.

[0515] [Synthesis Examples S5 and S6: Synthesis of Polymers S5 and S6 and Preparation of Adhesive Solutions S5 and S6]

[0516] In Synthesis Example S3, compounds that introduce each constituent component are used to make polymers S5 and S6 have the compositions shown in Table 1 (types and amounts of constituent components). Otherwise, polymers S5 and S6 (acrylic polymers) are synthesized in the same manner as in Synthesis Example S3, and solutions S5 and S6 of polymer adhesives composed of these polymers are obtained respectively.

[0517] [Synthesis Example S7: Synthesis of Polymer S7 and Preparation of Adhesive Dispersion S7]

[0518] 200 g of heptane was injected into a 1 L three-necked flask equipped with a reflux condenser and a gas inlet plug. Nitrogen gas was introduced at a flow rate of 200 mL / min for 10 minutes, and the temperature was raised to 80 °C. A liquid prepared in a separate container (a mixture of 177 g of ethyl acrylate (manufactured by FUJIFILM Wako Pure Chemical Corporation), 13 g of acrylic acid (manufactured by FUJIFILM Wako Pure Chemical Corporation), 100 g of macromonomer AB-6 (trade name, manufactured by Toagosei Company, Limited) (solid content), and 2.0 g of polymerization initiator V-601 (manufactured by FUJIFILM Wako Pure Chemical Corporation) was added dropwise over 2 hours, and the mixture was stirred at 80 °C for 2 hours. 1.0 g of V-601 was further added to the resulting mixture, and the mixture was stirred at 90 °C for 2 hours. By diluting the obtained solution with heptane, a dispersion S7 of a particulate binder composed of polymer S7 (concentration 10% by mass, particle size 150 nm) was obtained.

[0519] [Synthetic Examples S8-S14: Synthesis of Polymers S8-S14 and Preparation of Adhesive Solutions S8-S14]

[0520] In Synthesis Example S3, compounds that introduce each constituent component are used to make polymers S8 to S14 have the composition shown in Table 1 (types and amounts of constituent components). Otherwise, polymers S8 to S13 (acrylic polymer) and polymer S14 (vinyl polymer) are synthesized in the same manner as in Synthesis Example S3, and solutions S8 to S14 of polymer adhesives composed of these polymers are obtained respectively.

[0521] [Synthesis Example S15: Synthesis of Polymer S15 and Preparation of Adhesive Solution S15]

[0522] In Synthesis Example S1, compounds that introduce each constituent component are used to make polymer S15 have the composition shown in Table 1 (types and amounts of constituent components). Otherwise, polymer S15 (polyurethane) is synthesized in the same manner as in Synthesis Example S1, and a solution S15 of adhesive composed of polymer S15 is obtained.

[0523] [Synthetic Example S16: Synthesis of Polymer S16 and Preparation of Adhesive Dispersion S16]

[0524] In Synthesis Example S7, compounds that introduce each constituent component are used to make polymer S16 have the composition shown in Table 1 (type and content of constituent components). Otherwise, polymer S16 is synthesized in the same manner as in Synthesis Example S7, and a dispersion S16 of particulate binder (concentration 10% by mass, particle size 120 nm) composed of polymer S16 is obtained.

[0525] The synthesized polymers S1–S3, S5, S6, and S8–S15 are shown below. Additionally, polymer S4 is identical to polymer S3 except for the content of its constituent components; therefore, its chemical formula is omitted. The numbers listed in the lower right corner of each constituent component indicate its content (mol%).

[0526] [Chemical Formula 12]

[0527]

[0528] [Chemical Formula 13]

[0529]

[0530] Table 1 shows the composition of each synthesized polymer (adhesive), the presence or absence of functional groups, the mass-average molecular weight determined by the above method, and the form (soluble or insoluble) of the adhesive in the compositions described below. Furthermore, the content of each component is expressed in "mol%", but this is omitted in Table 1. The form of the adhesive was determined by measuring its solubility in the dispersion medium (butyl butyrate) used in each composition using the above method.

[0531] Furthermore, regarding the prepared polymer binders, the adsorption rate A of the inorganic solid electrolyte (SE) (LPS with an average particle size of 2.5 μm synthesized in Synthesis Example A) used in the preparation of the cathode composition described later was determined by the above method. SE and the adsorption rate A of the active substance (AC)(NMC111). AC Furthermore, the difference in adsorption rates (A) was calculated. AC With A SE (The absolute value of the difference). On the other hand, regarding the prepared polymer binders S1 to S4, the adsorption rate A of the inorganic solid electrolyte (SE) (LPS with an average particle size of 2.5 μm synthesized in Synthesis Example A) used in the preparation of the negative electrode composition described later was determined by the above method. SE and the adsorption rate A of the active substance (AC)(LTO). AC Furthermore, the difference in adsorption rates (A) was calculated. AC With A SE The absolute value of the difference). The results obtained are recorded in Table 1. Additionally, regarding polymer binders S1 to S4, see "A" in Table 1. ACIn the column, "Adsorption rate A of positive electrode active material" AC "and "Adsorption rate A of negative electrode active material AC "Record it by " / ", and in the "Difference" column, "Adsorption rate A of positive electrode active material" AC Adsorption rate A of inorganic solid electrolytes SE The difference between "the adsorption rate of the negative electrode active material A" and "the adsorption rate of the negative electrode active material A" AC Adsorption rate A of inorganic solid electrolytes SE The difference is indicated by a " / ". Additionally, using the active material (AC) taken from the active material of the positive or negative electrode obtained later in <Preparation of Positive Electrode for All-Solid-State Secondary Batteries>, the inorganic solid electrolyte (SE), polymer binder A and polymer binder B, and the dispersion medium (D) used in the preparation of the positive or negative electrode composition, the adsorption of A was measured. SE and adsorption rate A AC The result is the same.

[0532] [Table 1]

[0533]

[0534] <Abbreviation for table>

[0535] In the table, a "-" in the component column indicates that the corresponding component is not present.

[0536] H12MDI: Dicyclohexylmethane 4,4'-diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0537] HMDI: Hexamethylene diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0538] GI-3000: NISSO-PB GI-3000 (trade name, hydrogenated polybutadiene with hydroxyl ends, number average molecular weight 3100, manufactured by Nippon Soda Co., Ltd.)

[0539] HEA: 2-Hydroxyethyl Acrylate (manufactured by FUJIFILM Wako Pure Chemical Corporation)

[0540] LA: Dodecyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0541] OA: Octyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0542] EA: Ethyl acrylate (manufactured by FUJIFILM Wako Pure Chemical Corporation)

[0543] AA: Acrylic acid (manufactured by FUJIFILM Wako Pure Chemical Corporation)

[0544] AB-6: Polybutyl acrylate with methacryloyl terminal functional group (number average molecular weight 6000, manufactured by Toagosei Company, Limited).

[0545] PHOSMER M: Methacrylate with phosphate groups (trade name, manufactured by Uni-Chemical Co., Ltd.)

[0546] DMAEM: N,N-Dimethylaminoethyl (manufactured by FUJIFILM Wako Pure Chemical Corporation)

[0547] NMI: N-Methylmaleimide (manufactured by FUJIFILM Wako Pure Chemical Corporation)

[0548] EDA: Ethylenediamine (manufactured by FUJIFILM Wako Pure Chemical Corporation)

[0549] St: Styrene (manufactured by FUJIFILM Wako Pure Chemical Corporation)

[0550] Other components not specifically described used compounds manufactured by FUJIFILM Wako Pure Chemical Corporation.

[0551] 2. Synthesis of sulfide-based inorganic solid electrolytes [Synthesis Example A]

[0552] The sulfide-based inorganic solid electrolyte was synthesized with reference to non-patent literature, T. Ohtomo, A. Hayashi, M. Tatsumisago, Y. Tsuchida, S. Hama, K. Kawamoto, Journal of Power Sources, 233, (2013), pp231-235 and A. Hayashi, S. Hama, H. Morimoto, M. Tatsumisago, T. Minami, Chem. Lett., (2001), pp872-873.

[0553] Specifically, 2.42 g of lithium sulfide (Li₂S, manufactured by Aldrich, Inc., purity > 99.98%) and 3.90 g of phosphorus pentasulfide (P₂S₅, manufactured by Aldrich, Inc., purity > 99%) were weighed out in a glove box under an argon atmosphere (dew point -70°C) and added to an agate mortar. The mixture was then mixed for 5 minutes using an agate pestle. The molar ratio of Li₂S to P₂S₅ was set as Li₂S:P₂S₅ = 75:25.

[0554] Next, 66g of 5mm diameter zirconia beads were added to a 45mL zirconia container (manufactured by Fritsch Co., Ltd.), along with the total amount of the aforementioned mixture of lithium sulfide and phosphorus pentasulfide. The container was then sealed under an argon atmosphere. The container was placed in a planetary ball mill P-7 (trade name, manufactured by Fritsch Co., Ltd.) and mechanically ground (micronized) at 25°C and 510 rpm for 20 hours to obtain 6.20g of a yellow powder sulfide-based inorganic solid electrolyte (Li / P / S glass, hereinafter, sometimes labeled LPS). The particle size (volume average particle size) of this LPS was 8μm.

[0555] The obtained LPS was wet-dispersed under the following conditions, thereby adjusting the particle size of the LPS.

[0556] Specifically, 160 zirconia beads with a diameter of 5 mm were added to a 45 mL zirconia container (made by Fritsch Co., Ltd.), and 4.0 g of synthesized LPS and 6.0 g of diisobutyl ketone as an organic solvent were added. The container was then placed in a planetary ball mill P-7 and wet-dispersed at 250 rpm for 30 minutes to obtain LPS with a particle size (volume average particle size) of 2.5 μm.

[0557] [Example 1]

[0558] <Preparation of Positive Electrode Composition (Slurry) S-1>

[0559] A positive electrode composition (65% by mass) S-1 was prepared by mixing 70 parts by mass of NMC111 (lithium nickel manganese cobalt oxide, 5 μm particle size, manufactured by Aldrich, CO.LTD.) as the positive electrode active material (AC), 27 parts by mass of LPS (2.5 μm particle size) obtained from the above synthesis example A as the inorganic solid electrolyte (SE), 2.3 parts by mass of acetylene black (0.1 μm particle size, manufactured by Denka Company Limited) as the conductive additive (CA), 0.7 parts by mass of polymer binder solution S1 (converted to solid content) as polymer binder A, 0.27 parts by mass of polymer binder solution S3 (converted to solid content) as polymer binder B, and dispersion medium (D) through steps 1, 2 and 3 described below.

[0560] (Step 1: Preparation of Active Substance Composition)

[0561] 20g of 3mm diameter zirconia beads were added to a 45mL zirconia container (manufactured by Fritsch Co., Ltd.), followed by 70 parts by mass of the aforementioned positive electrode active material, 0.7 parts by mass of binder solution S1 (solid content conversion), and butyl butyrate as a dispersion medium, adjusting the solid content concentration to 70% by mass. The container was then placed in a planetary ball mill P-7 (trade name, manufactured by Fritsch Co., Ltd.) and stirred at 25°C and 100 rpm for 30 minutes to obtain an active material composition S1-1 with a solid content concentration of 70% by mass.

[0562] (Step 2: Preparation of solid electrolyte composition)

[0563] 20g of 3mm diameter zirconia beads were added to a 45mL zirconia container (manufactured by Fritsch Co., Ltd.), followed by 27 parts by mass of inorganic solid electrolyte, 0.27 parts by mass of binder solution S3 (solid composition conversion), and butyl butyrate as a dispersion medium, adjusting the solid composition concentration to 60% by mass. The container was then placed in a planetary ball mill P-7 and stirred at 25°C and 100 rpm for 30 minutes to obtain a solid electrolyte composition S1-2 with a solid composition concentration of 60% by mass.

[0564] (Step 3: Electrode composition preparation step)

[0565] 20g of 3mm diameter zirconia beads were added to a 45mL zirconia container (manufactured by Fritsch Co., Ltd.). The total amount of the active material composition S1-1 obtained in step 1, the total amount of the solid electrolyte composition S1-2 obtained in step 2, 2.3 parts by mass of acetylene black, and the dispersion medium required to adjust the solid content concentration of the obtained cathode composition to 65% by mass were then added. The container was then placed in a planetary ball mill P-7 and stirred at 25°C and 100 rpm for 30 minutes to obtain cathode composition S-1 (65% by mass solid content).

[0566] <Preparation of positive electrode compositions (slurry) S-2 to S-24>

[0567] In the preparation of positive electrode composition (slurry) S-1, the type or content of polymer binder A, the type or content of polymer binder B, and the content of conductive additive were changed as shown in Table 2-1. Otherwise, positive electrode compositions (slurries) S-2 to S-24 were prepared in the same manner as the preparation of positive electrode composition (slurry) S-1.

[0568] <Preparation of negative electrode compositions (slurries) T-1 to T-4>

[0569] In the preparation of positive electrode composition (slurry) S-1, the type or content of polymer binder A, the type or content of polymer binder B, and the type and content of active material and conductive additive were changed as shown in Table 2-2. Otherwise, negative electrode compositions (slurries) T-1 to T-4 were prepared in the same manner as the preparation of positive electrode composition (slurry) S-1.

[0570] In Tables 2-1 and 2-2 (collectively referred to as Table 2), the adsorption rate A is discussed. AC and adsorption rate A SE The difference (absolute value) between polymer adhesive A and polymer adhesive B was calculated and is shown in Table 2.

[0571] Polymer adhesives S5 to S7 and S16 do not correspond to polymer adhesives A and B as defined in this invention. However, for convenience, in the positive electrode compositions S-3 to S-10 and S-24 shown in Table 2, the polymer used in step 1 is recorded in the "Adhesive A" column, and the polymer adhesive used in step 2 is recorded in the "Adhesive B" column.

[0572] In addition, in Table 2, the content of each component indicates the amount (parts by mass) of the mixture used to prepare each composition, but the unit is omitted in the table.

[0573] [Table 2-1]

[0574]

[0575] [Table 2-2]

[0576]

[0577] <Abbreviation for table>

[0578] NMC111: LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (manufactured by Aldrich, CO.LTD.) LPS: 2.5 μm LPS synthesized in Example A B: Acetylene Black (manufactured by Denka Company Limited) LTO: Lithium Titanate (manufactured by Aldrich, CO.LTD.)

[0579] <Fabrication of Positive Electrode Sheets for All-Solid-State Secondary Batteries>

[0580] Using a baking-type applicator (trade name: SA-201, manufactured by TESTER SANGYO CO,.LTD.), the above-obtained positive electrode compositions S-1 to S-24 were coated onto aluminum foil with a thickness of 20 μm. The positive electrode compositions were then dried (dispersion medium removed) by heating at 100°C for 1 hour. This formed a positive electrode active material layer on the aluminum foil, thus fabricating positive electrode sheets P-1 to P-24 for all-solid-state secondary batteries. The thickness of the positive electrode active material layer was 110 μm.

[0581] <Fabrication of negative electrode sheets for all-solid-state secondary batteries>

[0582] Using a baking-type applicator (trade name: SA-201, manufactured by TESTER SANGYO CO,.LTD.), the aforementioned negative electrode compositions T-1 to T-4 were coated onto a 20 μm thick stainless steel (SUS) foil. The negative electrode compositions were then dried (removing the dispersion medium) by heating at 100°C for 1 hour. This formed a negative electrode active material layer on the SUS foil, thus fabricating negative electrode sheets N-1 to N-4 for all-solid-state secondary batteries. The thickness of the negative electrode active material layer was 100 μm.

[0583] <Manufacturing of All-Solid-State Secondary Batteries>

[0584] The prepared positive electrode sheets P-1 to P-24 and negative electrode sheets N-1 to N-4 for all-solid-state secondary batteries were stamped into 10 mm diameter discs and placed inside a 10 mm inner diameter polyethylene terephthalate (PET) cylinder. 30 mg of LPS with a particle size of 2.5 μm obtained in Synthesis Example A was placed into the positive electrode active material layer side inside each cylinder, and 10 mm diameter stainless steel rods (SUS rods) were inserted from both ends of the cylinder. A pressure of 350 MPa was applied to the current collector side of each positive electrode sheet and the LPS using the SUS rods. After temporarily removing the SUS rods from the LPS side, 9 mm diameter disc-shaped In sheets (20 μm thick) and 9 mm diameter disc-shaped Li sheets (20 μm thick) were inserted onto the LPS inside the cylinder in this order. The removed SUS rod was reinserted into the cylinder and secured under a pressure of 50 MPa.

[0585] Thus, all-solid-state secondary batteries (positive electrode half-cells) No. C-1 to C-24 with the structure of aluminum foil (thickness 20 μm) - positive electrode active material layer (thickness 70 μm) - solid electrolyte layer (thickness 200 μm) - negative electrode active material layer (In / Li sheet, thickness 30 μm) were manufactured, and all-solid-state secondary batteries (negative electrode half-cells) No. C-25 to C-28 with the structure of SUS foil (thickness 20 μm) - negative electrode active material layer (thickness 70 μm) - solid electrolyte layer (thickness 200 μm) - positive electrode active material layer (In / Li sheet, thickness 30 μm) were manufactured.

[0586] The various compositions, sheets, and all-solid-state secondary batteries manufactured were evaluated as follows, and the results are shown in Tables 3-1 and 3-2 (collectively referred to as Table 3).

[0587] <Evaluation 1: Dispersion Stability Test>

[0588] The prepared compositions (slurries) S-1 to S-24 and T-1 to T-4 were placed into glass test tubes with a diameter of 10 mm and a height of 4 cm until the height reached 4 cm, and allowed to stand at 25°C for 3 hours. The solid content ratio of the slurry was calculated from 1 cm above the surface before and after standing. Specifically, immediately after standing, 1 cm of liquid was taken from the surface of the slurry and dried in an aluminum cup at 120°C for 3 hours. The mass of the solid content in the cup was then measured, and the solid content of each component before and after standing was determined. The solid content ratio [W2 / W1] of the solid content W2 obtained after standing was calculated relative to the solid content W1 before standing.

[0589] The ease (precipitability) of precipitation of the active material (AC) and the inorganic solid electrolyte (SE) was evaluated as a measure of the dispersion stability of the solid electrolyte composition, based on which of the following evaluation criteria the solid component ratio [W2 / W1] falls into. In this test, the closer the solid component ratio [W2 / W1] is to 1, the better the dispersion stability, and an evaluation criterion of "B" or above is considered acceptable.

[0590] Furthermore, the electrode compositions S-1, S-2, S-11 to S-23, and T-1 and T-2 exhibit excellent dispersibility immediately after preparation. On the other hand, the solid content ratios [W2 / W1] of electrode compositions S-3 and S-4 are 0.58 and 0.61, respectively.

[0591] -Evaluation Criteria-

[0592] S: 0.95 ≤ [W2 / W1] ≤ 1.0

[0593] A: 0.90 ≤ [W2 / W1] < 0.95

[0594] B: 0.8 ≤ [W2 / W1] < 0.90

[0595] C: [W2 / W1] < 0.8

[0596] <Evaluation 2: Adhesion Test (Vibration Test)>

[0597] The prepared positive electrode sheets or P-1 to P-24 and negative electrode sheets N-1 to N-4 for all-solid-state secondary batteries were punched into 10mm diameter discs and placed on the bottom of a spiral tube (manufactured by Maruemu Corporation, No. 6, capacity 30mL, tube diameter 30mm × total length 65mm). The disc-shaped test pieces were not fixed with the active material layer on the top side and were sealed. The spiral tube was fixed to a test tube mixer (trade name: Delta Mixer Se-40, TIETECH Co., Ltd.), and the amplitude was set to 2800 rotations / min for 30 seconds.

[0598] For the disc-shaped test piece taken out of the spiral tube after the vibration test, the mass ratio [WB2 / WB1] of the test piece after vibration to the mass of the test piece before vibration is calculated as the deficiency ratio of the active material layer.

[0599] In this experiment, the closer the mass ratio [WB2 / WB1] is to 1, the stronger the adhesion between the solid particles constituting the active material layer. Evaluation standard "B" and above is considered qualified.

[0600] -Evaluation Criteria-

[0601] A: 0.99 ≤ [WB2 / WB1] ≤ 1.0

[0602] B: 0.95 ≤ [WB2 / WB1] < 0.99

[0603] C: [WB2 / WB1] < 0.95

[0604] <Evaluation 3: Resistance Test>

[0605] The resistance of each of the manufactured all-solid-state secondary batteries was evaluated using the following method.

[0606] Specifically, each of the manufactured all-solid-state secondary batteries (half-cells) No. C-1 to C-28 was charged at 25°C with a charging current of 0.1mA until the battery voltage reached 3.6V. Then, the batteries were discharged at a discharge current of 0.1mA until the battery voltage reached 1.9V, thus initializing each all-solid-state secondary battery.

[0607] Then, as a rate test, the battery was charged at 25°C with a charging current of 0.1mA until the battery voltage reached 3.6V, and then discharged at a discharging current of 0.1mA until the battery voltage reached 1.9V (charge-discharge step (1)). Then, the battery was charged at a charging current of 0.1mA until the battery voltage reached 3.6V, and then discharged at a discharging current of 1.5mA until the battery voltage reached 1.9V (charge-discharge step (2)).

[0608] After the charging and discharging processes (1) and (2) were completed, the discharge capacity was measured using a charging and discharging evaluation device TOSCAT-3000 (trade name, manufactured by TOYO SYSTEM Co., Ltd.). Using the measured discharge capacity, the discharge capacity retention rate (%) was calculated using the following formula, and the rate characteristics of the all-solid-state secondary battery were evaluated using the following evaluation criteria.

[0609] In this test, the higher the retention rate (%), the lower the battery resistance (resistance of the positive electrode active material layer) of the all-solid-state secondary battery. Evaluation standard "B" and above is the qualified level of this test.

[0610] Maintenance rate (%) = [Discharge capacity of charge / discharge process (2) / Discharge capacity of charge / discharge process (1)] × 100

[0611] -Evaluation Criteria-

[0612] A: 90% ≤ Maintenance Rate

[0613] B: 80% ≤ Maintenance rate < 90%

[0614] C: Maintenance rate <80%

[0615] [Table 3-1]

[0616]

[0617] [Table 3-2]

[0618]

[0619] The results shown in Tables 1 to 3 reveal the following information.

[0620] The comparative electrode compositions S-3 to S-10, S-24, and T-3 to T-4, which do not contain polymer binders A and B, which preferentially adsorb onto the active material (AC) and inorganic solid electrolyte (SE), respectively, fail to simultaneously achieve good dispersion stability, adhesiveness of solid particles in the active material layer, and battery resistance (resistance of the active material layer). Specifically, electrode compositions S-3 to S-7, S-9, and T-3 to T-4 exhibit poor dispersion stability. Furthermore, while electrode composition S-8, containing excessive amounts of the two polymer binders that do not correspond to polymer binders A and B, demonstrates excellent dispersion stability, it also exhibits high battery resistance (resistance of the positive electrode active material layer). Positive electrode composition S-10, containing particulate polymer binders, exhibits poor dispersion stability, while positive electrode composition S-24 suffers from both poor dispersion stability and poor battery resistance.

[0621] In contrast, electrode compositions S-1, S-2, S-11 to S-23 and T-1, T-2 containing polymer binders A and B, which preferentially adsorb onto the active material (AC) and inorganic solid electrolyte (SE), respectively, in the dispersion medium (D) exhibit excellent dispersion stability, solid particle adhesion, and battery resistance, and these can be controlled at a high level.

[0622] Symbol Explanation

[0623] 1-Negative electrode current collector, 2-Negative electrode active material layer, 3-Solid electrolyte layer, 4-Positive electrode active material layer, 5-Positive electrode current collector, 6-Working part, 10-All-solid-state secondary battery.

Claims

1. An electrode composition comprising: an inorganic solid electrolyte having conductive ions of metals belonging to Group 1 or Group 2 of the periodic table, an active material, a polymer binder, and a dispersion medium. in, The polymer adhesive comprises: Polymer adhesive A, dissolved in the dispersion medium, wherein the adsorption rate A of the active substance in the dispersion medium is... AC The percentage is 20% or more and the adsorption rate A of the inorganic solid electrolyte is compared with that of the inorganic solid electrolyte. SE % large; and Polymer binder B, dissolved in the dispersion medium, exhibits an adsorption rate A of A for the inorganic solid electrolyte in the dispersion medium. SE The percentage is 20% or higher and the adsorption rate A of the active substance is higher. AC %big, The polymer forming the polymer adhesive A has at least one type of bond in its main chain, namely, urethane bond, urea bond, amide bond, imide bond, and ester bond. The polymer forming the polymeric adhesive B is synthesized by polymerizing monomers having carbon-carbon unsaturated bonds. The adsorption rate A AC The following measurements were performed: 1.6g of active material and 0.08g of polymer binder were placed in a 15mL vial. While stirring with a mixing rotor, 8g of dispersion medium was added. The mixture was then stirred at 80rpm for 30 minutes at room temperature (25°C). The resulting dispersion was filtered through a 1μm filter. 2g of the 8g filtrate was collected and dried. The mass of the dried polymer binder, i.e., the mass of the polymer binder not adsorbed onto the active material, was measured. Based on the mass BY of the polymer adhesive thus obtained and the mass 0.08 g of the polymer adhesive used, the adsorption rate A of the polymer adhesive for the active substance is calculated using the following formula. AC The adsorption rate % obtained by performing this measurement twice is set as the adsorption rate A of the polymer adhesive. AC %, Adsorption rate A AC % = [(0.08 - BY × 8 / 2) / 0.08] × 100; Adsorption rate A SE The following measurements were performed: 0.5 g of inorganic solid electrolyte and 0.26 g of polymer binder were placed in a 15 mL vial. While stirring with a mixing rotor, 25 g of dispersion medium was added. The mixture was then stirred at 80 rpm for 30 minutes at room temperature. The resulting dispersion was filtered through a 1 μm filter. 2 g of the 25 g filtrate was collected and dried. The mass of the dried polymer binder, i.e., the mass of the polymer binder not adsorbed onto the inorganic solid electrolyte, BX, was measured. Based on the mass BX of the polymer binder thus obtained and the mass of the polymer binder used (0.26 g), the adsorption rate A of the polymer binder for the inorganic solid electrolyte is calculated using the following formula. SE The adsorption rate % obtained by performing this measurement twice is set as the adsorption rate A of the polymer adhesive. SE %, Adsorption rate A SE % = [(0.26 - BX × 25 / 2) / 0.26] × 100.

2. The electrode composition according to claim 1, wherein it contains a conductive additive.

3. The electrode composition according to claim 1 or 2, wherein, The polymer forming at least one of the polymer adhesives A and B comprises a component having functional groups selected from group (a) below. <Functional Groups (a)> Hydroxyl, amino, carboxyl, sulfonyl, phosphate, phosphonic acid, thioalkyl, ether, imino, amide, imide, carbamate, urea, heterocyclic, aryl, carboxylic anhydride.

4. The electrode composition according to claim 1 or 2, wherein, In the 100% by mass of the solid components of the electrode composition, the content of the polymer binder A is 1.5% by mass or less. In the 100% by mass of the solid components of the electrode composition, the content of the polymer binder B is 1.5% by mass or less.

5. An electrode sheet for an all-solid-state secondary battery, having an active material layer formed using the electrode composition according to any one of claims 1 to 4.

6. An all-solid-state secondary battery, comprising sequentially a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer, wherein, At least one of the positive electrode active material layer and the negative electrode active material layer is an active material layer formed using the electrode composition according to any one of claims 1 to 4.

7. A method for manufacturing an electrode composition, wherein the method is the same as that for manufacturing the electrode composition according to any one of claims 1 to 4. This manufacturing method has the following characteristics: The step of preparing an active substance composition containing the active substance, the polymer binder A and the dispersion medium; The step of preparing a solid electrolyte composition containing the inorganic solid electrolyte, the polymer binder B, and the dispersion medium; and The process of mixing the active substance composition and the solid electrolyte composition.

8. A method for manufacturing an electrode sheet for an all-solid-state secondary battery, wherein, The electrode composition according to any one of claims 1 to 4 is used to form a film.

9. A method for manufacturing an all-solid-state secondary battery, wherein the all-solid-state secondary battery is manufactured by the manufacturing method described in claim 8.

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