Electrode sheet and all-solid-state secondary battery, and method for manufacturing the electrode sheet, electrode sheet and all-solid-state secondary battery.

Abstract

Provided are: a sheet for an electrode, the sheet comprising an active material layer precursor layer containing an inorganic solid electrolyte, an active material, and a polymer binder, wherein the active material layer precursor layer contains at most 3 mass% of the polymer binder, an exhibits a filling rate of 35-50%; a method for producing the same; an all-solid secondary battery; and methods for producing an electrode sheet and an all-solid secondary battery using said sheet for an electrode.

Description

[Technical Field]

[0001] The present invention relates to an electrode sheet and an all-solid-state secondary battery, as well as to a method for manufacturing the electrode sheet, the electrode sheet, and the all-solid-state secondary battery. [Background technology]

[0002] All-solid-state rechargeable batteries consist entirely of solid negative electrodes, electrolytes, and positive electrodes, significantly improving the safety and reliability issues associated with batteries using organic electrolytes. They are also expected to offer longer lifespans. Furthermore, all-solid-state rechargeable batteries can be constructed with electrodes and electrolytes directly arranged in series. Therefore, they enable higher energy density compared to rechargeable batteries using organic electrolytes, and are expected to have applications in electric vehicles and large-scale storage batteries.

[0003] In such all-solid-state secondary batteries, materials that form the active material layer (also called the electrode layer) include inorganic solid electrolytes and active materials. These inorganic solid electrolytes, in particular oxide-based inorganic solid electrolytes and sulfide-based inorganic solid electrolytes, are expected to be electrolyte materials with high ionic conductivity approaching that of organic electrolytes. The active material layer of an all-solid-state secondary battery is usually formed as an electrode sheet by dispersing or dissolving the above-mentioned inorganic solid electrolyte, active material, and binder (binding agent), etc., in a dispersion medium (also called an active material layer forming material or electrode composition) on a substrate and then forming a film (coating and drying) the film. For example, Patent Document 1 describes "a method for manufacturing an electrode laminate comprising an active material layer and a solid electrolyte layer on the surface of the active material layer, comprising an active material layer forming step for forming the active material layer, and a solid electrolyte layer forming step for forming the solid electrolyte layer on the active material layer by coating a slurry for a solid electrolyte layer onto the active material layer and drying it, wherein the product of the filling rate of the active material layer and the volume ratio of the active material in the active material layer is 0.33 or more and 0.41 or less." Patent Document 2 also describes a method for forming an active material layer by coating a slurry or paste containing an active material, a solid electrolyte, and various additives onto a current collector, drying it, and then rolling it. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2017-062939 [Patent Document 2] Japanese Patent Publication No. 2019-109998 [Overview of the project] [Problems that the invention aims to solve]

[0005] In active material layers formed from the aforementioned solid particles (inorganic solid electrolytes, active materials, conductive additives, etc.), the interfacial contact state between the solid particles, and furthermore, the interfacial contact state between the solid particles and the current collector, is restricted. As a result, interfacial resistance tends to increase, and the bonding force between the solid particles, and between the solid particles and the substrate (current collector), is not sufficient. All-solid-state secondary batteries having such active material layers result in increased battery resistance and a decrease in battery performance, such as cycle characteristics. Therefore, when producing active material layers from solid particles, methods or techniques have typically been employed to firmly bond the solid particles with a high packing density and reduced voids (in a dense state) from the electrode sheet stage, by using a relatively large amount of binder in combination or by pressing the active material layer. For example, Patent Document 1 (Example) includes a step of pressing an active material layer formed using 5 mass% binder, and sets the packing density of the active material layer to 51-77%. Furthermore, Patent Document 2 states that in order to increase the density ratio of the active material layer, the active material layer may be made to contain 5% by mass of binder, and then subjected to a pressing process such as roll pressing. However, when a relatively large amount of binder is used in combination, the binder exhibits electronic and ionic insulating properties, so even if the interfacial contact state of the solid particles can be improved, it will ultimately lead to an increase in resistance.

[0006] Incidentally, in recent years, research and development on improving the performance and practical application of electric vehicles has progressed rapidly, and the industrial manufacturing of all-solid-state secondary batteries used in them, such as continuous manufacturing methods like the roll-to-roll method, has also begun to be considered. In such industrial manufacturing methods, for example, the roll-to-roll method, in which a long base sheet wound on a roll is continuously supplied to the production line, an active material layer is formed on the base sheet, and the resulting electrode sheet is wound into a roll, is preferably employed. However, it has been found that when an electrode sheet having an active material layer with solid particles bound to a high packing rate is manufactured using the above-mentioned commonly employed method or technology, problems arise such as defects in the active material layer (cracks, fractures, chips, etc.) and even delamination from the base material (poor transportability) due to the breakdown of the solid particle binding during transport and roll winding in the production line. However, Patent Documents 1 and 2 do not address the suppression of the breakdown of solid particle binding during transport, etc.

[0007] The present invention aims to provide an electrode sheet that suppresses resistance increase while achieving high transportability and can be applied to industrial manufacturing methods while suppressing defect generation in the active material precursor layer, as well as a method for manufacturing the same. Furthermore, the present invention aims to provide an all-solid-state secondary battery using this electrode sheet, as well as a method for manufacturing the electrode sheet and the all-solid-state secondary battery. [Means for solving the problem]

[0008] The inventors of this invention have diligently investigated the packing state, resistance reduction, and transportability of the active material layer in electrode sheets. Contrary to conventional methods or techniques that involve binding solid particles together to form the active material layer with a high packing density, they have discovered that a layer formed by deliberately incorporating a small amount of polymer binder and then tightly bonding solid particles with a low packing density (sparse state) exhibits high transportability even when applied to industrial manufacturing methods. Furthermore, they have found that by pressing this layer formed by tightly bonding solid particles with a low packing density during the manufacturing process of an all-solid-state secondary battery, it is possible to convert it into an active material layer with a high packing density, and as a result, a low-resistance all-solid-state secondary battery can be manufactured. This invention was completed after further consideration based on these findings.

[0009] In other words, the above problems were solved by the following means. <1> An electrode sheet comprising an active material precursor layer containing an inorganic solid electrolyte having conductivity of metal ions belonging to Group 1 or Group 2 of the periodic table, an active material, and a polymer binder, An electrode sheet in which the active material precursor layer contains a polymer binder in an amount of 3% by mass or less and exhibits a packing density of 35-50%. <2> The active material precursor layer has a layer thickness of 150 μm or more. <1> Electrode sheets as described above. <3> The inorganic solid electrolyte is a sulfide-based inorganic solid electrolyte. <1> or <2> Electrode sheets as described above. <4> The particle size of the inorganic solid electrolyte is 0.1 to 2.5 μm. <1> ~ <3> An electrode sheet as described in one of the following. <5> The active material precursor layer contains 1.4-2.0 g / cm³ 3 This is a cathode active material layer precursor layer having a film density. <1> ~ <4> An electrode sheet as described in one of the following. <6> The active material precursor layer contains 0.8-1.0 g / cm³ 3 This is a negative electrode active material layer precursor layer having a film density. <1> ~ <4> An electrode sheet as described in one of the following. <7> An electrode composition containing an inorganic solid electrolyte having the conductivity of metal ions belonging to Group 1 or Group 2 of the periodic table, an active material, a polymer binder, and a dispersion medium is applied to a substrate and dried to form an active material layer precursor layer. <1> ~ <6> A method for manufacturing an electrode sheet as described in any one of the following: A step of preparing an electrode composition by setting the solid content of the polymer binder to 3% by mass or less, A method for manufacturing an electrode sheet, comprising the step of setting the packing ratio of the active material precursor layer to 35-50%. <8> A method for manufacturing an electrode sheet having an active material layer on a substrate, the above <7> A method for manufacturing an electrode sheet, comprising pressing the active material layer precursor layer of an electrode sheet obtained by the method for manufacturing an electrode sheet described above to form an active material layer. <9> A method for manufacturing an all-solid-state secondary battery comprising a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order, At least one of the positive electrode active material layer and the negative electrode active material layer, <7> A method for manufacturing an all-solid-state secondary battery, comprising pressing together an electrode sheet obtained by the method for manufacturing an electrode sheet described above with a solid electrolyte layer or a solid electrolyte layer forming material. <10> the above <9> An all-solid-state secondary battery manufactured by the method for manufacturing all-solid-state secondary batteries described above. [Effects of the Invention]

[0010] The present invention provides an electrode sheet that suppresses resistance increase while achieving high transportability and can be applied to industrial manufacturing methods while suppressing the occurrence of defects in the active material layer, as well as a method for manufacturing the same. Furthermore, the present invention aims to provide an all-solid-state secondary battery using this electrode sheet, as well as a method for manufacturing the electrode sheet and the all-solid-state secondary battery. The above and other features and advantages of the present invention will become more apparent from the following description, with reference to the accompanying drawings as appropriate. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a schematic longitudinal cross-sectional view showing an electrode sheet according to a preferred embodiment of the present invention. [Figure 2] Figure 2 is a schematic longitudinal cross-sectional view showing an all-solid-state secondary battery according to a preferred embodiment of the present invention. [Modes for carrying out the invention]

[0012] In this invention, a numerical range represented using "~" means a range that includes the values ​​written before and after "~" as the lower and upper limits. In this invention, when multiple numerical ranges are set and explained for the content of components, physical properties, etc., the upper and lower limits that form the numerical range are not limited to the specific combinations written before and after "~" as a specific numerical range, but can be numerical ranges that are appropriately combined from the upper and lower limits of each numerical range. In this invention, the designation of a compound (for example, when referring to it with "compound" at the end) includes not only the compound itself, but also its salts and ions. It also includes derivatives in which parts have been altered, such as by introducing substituents, to the extent that the effects of this invention are not impaired. In this invention, (meth)acrylic means either or both acrylic and methacrylic. The same applies to (meth)acrylate. In the present invention, substituents, linking groups, etc. (hereinafter referred to as substituents, etc.) that are not explicitly stated as substituted or unsubstituted may have appropriate substituents. Therefore, even when simply referred to as a YYY group in the present invention, this YYY group includes not only the unsubstituted form but also the form with substituents. The same applies to compounds that are not explicitly stated as substituted or unsubstituted. A preferred substituent is, for example, substituent Z, which will be described later. In the present invention, when there are multiple substituents indicated by specific symbols, or when multiple substituents are specified simultaneously or alternatively, it means that each substituent may be the same as or different from the others. Furthermore, even if not specifically stated otherwise, when multiple substituents are adjacent to each other, they may be linked to each other or fused to form a ring. In this invention, "polymer" means a polymer and is synonymous with so-called high-molecular-weight compounds. Furthermore, "polymer binder" (also simply called "binder") means a binder composed of polymers and includes both the polymer itself and binders composed (formed) containing polymers.

[0013] In the present invention, the electrode sheet includes a positive electrode sheet having a positive electrode active material precursor layer whose active material precursor layer is converted into a positive electrode active material layer of an all-solid-state secondary battery, and a negative electrode sheet having a negative electrode active material precursor layer which is converted into a negative electrode active material layer of an all-solid-state secondary battery. Similarly, the electrode sheet also includes a positive electrode sheet having a positive electrode active material layer and a negative electrode sheet having a negative electrode active material layer. In the present 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 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, and this composition usually does not contain an active material. In the present invention, the electrode composition includes a positive electrode composition containing a positive electrode active material and a negative electrode composition containing a negative electrode active material. Therefore, either or both of the positive electrode composition and the negative electrode composition may be simply referred to as the electrode composition, and either or both of the positive electrode active material layer and the negative electrode active material layer may be simply referred to as the active material layer or electrode active material layer. Furthermore, either or both of the positive electrode active material and the negative electrode active material may be simply referred to as the active material or electrode active material.

[0014] [Electrode Sheet] The electrode sheet of the present invention comprises an active material layer precursor layer containing an inorganic solid electrolyte having conductivity of metal ions belonging to Group 1 or Group 2 of the periodic table, an active material, and a polymer binder, and is suitably used as a material sheet for manufacturing an electrode sheet, an active material layer for an all-solid-state secondary battery, or a laminate (electrode) of a current collector and an active material layer. In this electrode sheet, the active material precursor layer contains a polymer binder in an amount of 3% by mass or less and exhibits a low packing density of 35-50%. Electrode sheets equipped with such an active material precursor layer suppress resistance increases while achieving high transportability, and even when applied to industrial manufacturing methods, the occurrence of defects in the active material precursor layer can be suppressed. Furthermore, if a substrate is present, delamination between the substrate and the active material precursor layer can also be suppressed. As a result, the electrode sheet, upon conversion to an active material layer, can suppress the resistance increase of the all-solid-state secondary battery.

[0015] The exact reasons are not yet clear, but they can be considered as follows: The active material precursor layer of the electrode sheet has a polymer binder content of 3% by mass or less, and a filling rate of 35-50%, as described later. This allows for maintaining the adhesion of solid particles while suppressing the increase in resistance due to the polymer binder content, and also exhibits flexibility. As a result, it can mitigate stresses (e.g., compressive stress, tensile stress) acting during transport and winding in industrial manufacturing methods, allowing it to follow bending well and suppress the collapse of solid particle adhesion while maintaining low resistance. Furthermore, by pressing the active material precursor layer during the manufacturing of all-solid-state secondary batteries, a low-resistance active material layer with a filling rate increased to the level required for the active material layer of all-solid-state secondary batteries can be formed. Consequently, it is believed that the electrode sheet of the present invention can suppress the occurrence of defects in the active material precursor layer even when applied to industrial manufacturing methods, and can be converted into the active material layer required for all-solid-state secondary batteries by pressing, thereby achieving the suppression of resistance increase required for all-solid-state secondary batteries. All-solid-state secondary batteries with suppressed resistance increases are less prone to overcurrent during charging and discharging, preventing degradation of solid particles and resulting in excellent cycle characteristics without a significant decrease in battery performance even after repeated charging and discharging. On the other hand, all-solid-state secondary batteries manufactured using electrode sheets with excellent transport properties are less prone to defects in the active material layer, and it is believed that the occurrence of short circuits can be suppressed.

[0016] The electrode sheet preferably includes a substrate, particularly a substrate that functions as a current collector in an all-solid-state secondary battery. In this case, the occurrence of delamination between the active material layer precursor and the substrate due to the collapse of solid particles can also be suppressed. When the electrode sheet has a substrate, the active material layer precursor is disposed on the substrate directly or via other layers. The active material layer precursor, substrate, and other layers constituting the electrode sheet may each have a single-layer or multi-layer structure, as long as they perform their respective functions. The electrode sheet of the present invention is not particularly limited in its other configurations as long as it has the above-described configuration, and for example, known configurations relating to electrode sheets used in all-solid-state secondary batteries can be adopted. For example, the electrode sheet may have other layers in addition to the above-described layers. Examples of other layers include a protective layer (release sheet), a coating layer, and so on. The electrode sheet of the present invention may be a single sheet, but it is preferably a long sheet due to its superior transportability. Furthermore, the electrode sheet includes sheets cut into predetermined shapes (sheet material) for use in the manufacture of all-solid-state secondary batteries, such as plates or discs cut into shapes depending on the shape of the all-solid-state secondary battery.

[0017] Figure 1 schematically shows a preferred embodiment of the electrode sheet of the present invention. This electrode sheet 11 has a structure in which a base material 8 and an active material precursor layer 9 are laminated in that order, and the base material 8 and the active material precursor layer 9 each have a single-layer structure and are in contact with each other.

[0018] <Base material> The substrate for the electrode sheet is not particularly limited as long as it can support the active material layer precursor layer, and examples include sheets (plate-like bodies) of materials such as current collectors, organic materials, and inorganic materials, which will be described later, with the materials described in the current collector section being preferred. Examples of organic materials include various polymers, specifically polyethylene terephthalate, polypropylene, polyethylene, and cellulose. Examples of inorganic materials include glass and ceramics.

[0019] <Active material layer precursor layer> The active material precursor layer is a precursor layer that is converted into an electrode sheet and an active material layer for an all-solid-state secondary battery by pressing. It contains an inorganic solid electrolyte having conductivity of metal ions belonging to Group 1 or Group 2 of the periodic table, an active material, and a polymer binder. Details of each component contained in the active material precursor layer will be described later. This active material precursor layer exhibits a packing density of 35% to 50%. When the packing density of the active material precursor layer is 50% or less, high transportability of the electrode sheet can be achieved while maintaining battery characteristics (suppression of resistance increase). On the other hand, when the packing density is 35% or more, the strength necessary for handling and transporting the active material precursor layer (strength as a self-supporting film) can be secured. The packing density of the active material precursor layer is preferably 35-48%, and more preferably 38-46%, as it allows for conversion into an active material layer with low resistance and high packing density, where solid particles are firmly bonded, and enables a higher level of balance between transportability and battery characteristics. In the present invention, the packing density of the active material precursor layer is the film density (g / cm³) of the active material precursor layer. 3 ) and the true density (g / cm³) of the active material precursor layer 3 The value shall be calculated from the following formula. Filling rate (%)=(film density / true density)×100 Here, the film density of the active material layer precursor layer (g / cm³) 3 This value is obtained by dividing the mass of the active material precursor layer by the volume of the active material precursor layer, and can be calculated by the method and conditions described in the examples. True density of the active material precursor layer (g / cm³) 3) means the density that does not consider the interstitial volume generated between solid particles constituting the active material layer precursor layer. This true density is a value obtained by dividing the mass of the solid particles constituting the active material layer precursor layer by the true volume of the solid particles, and is calculated as the sum of the products of the true density and the content ratio calculated for each type of solid particle. The true density of the solid particles can be measured, for example, at 25 °C by the gas replacement method using a density measuring device: BELPYCNO (trade name, manufactured by Microtrac Bell Co., Ltd.). The true volume means the volume considering only the volume of the solid particles and not considering the interstitial volume generated between the solid particles.

[0020] The method for setting the filling rate of the active material layer precursor layer within the above range will be described in the method for manufacturing the electrode sheet described later.

[0021] The active material layer precursor layer includes, in addition to the coating and drying layer itself obtained by coating and drying the electrode composition described later, a layer obtained by performing a treatment usually performed on this coating and drying layer. For example, it includes a precursor layer obtained by pressurizing (such as roll pressing) the coating and drying layer within a range where the filling rate does not deviate.

[0022] The film density of the active material layer precursor layer is not particularly limited and is appropriately set in consideration of the filling rate, layer thickness, etc. For example, it can be 0.8~2.2 g / cm 3 and can also be 0.8~2.0 g / cm 3 When the electrode sheet of the present invention is a positive electrode sheet, it is preferably 1.4~2.2 g / cm 3 and is also preferably 1.4~2.0 g / cm 3 On the other hand, when the electrode sheet of the present invention is a negative electrode sheet, the film density of the negative electrode active material layer precursor layer is preferably 0.8~1.0 g / cm 3 The method for setting the film density of the active material layer precursor layer within the above range will be described in the method for manufacturing the electrode sheet described later.

[0023] The thickness (film thickness) of the active material precursor layer is appropriately determined considering the thickness of the active material layer of the all-solid-state secondary battery, the amount of compression by pressing, etc. For example, it can be 10 to 1,000 μm, preferably 50 to 500 μm, and more preferably 100 to 300 μm. The electrode sheet of the present invention exhibits high transportability (bending resistance), so the layer thickness can also be increased. For example, it can be 100 μm or more, preferably 150 μm or more, and more preferably 200 μm or more. There is no particular upper limit, for example, it can be 1,000 μm or less, preferably 500 μm or less, and more preferably 300 μm or less.

[0024] The following describes the components that make up the active material precursor layer. Furthermore, the physical properties of the solid particles contained in the active material precursor layer are the same as those of the solid particles used to form the active material precursor layer, and the physical properties of the solid particles in the active material precursor layer can be appropriately set by adjusting the physical properties of the solid particles used.

[0025] <Inorganic solid electrolyte> The electrode composition of the present invention contains an inorganic solid electrolyte. In this invention, an inorganic solid electrolyte refers to an inorganic solid electrolyte, and a solid electrolyte is a solid electrolyte that can move ions within itself. Since it does not contain organic materials as the main ion-conducting material, it is clearly distinguished from organic solid electrolytes (polymer electrolytes such as polyethylene oxide (PEO), and organic electrolyte salts such as lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)). Furthermore, since inorganic solid electrolytes are solid in a steady state, they do not usually dissociate or become liberated into cations and anions. In this respect, they are clearly distinguished from inorganic electrolyte salts (LiPF6, LiBF4, lithium bis(fluorosulfonyl)imide (LiFSI), LiCl, etc.) that dissociate or become liberated into cations and anions in the electrolyte or polymer. Inorganic solid electrolytes are not particularly limited as long as they have conductivity of metal ions belonging to Group 1 or Group 2 of the periodic table, and generally, they do not have electronic conductivity.

[0026] 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, examples of inorganic solid electrolytes include (i) sulfide-based inorganic solid electrolytes, (ii) oxide-based inorganic solid electrolytes, (iii) halide-based inorganic solid electrolytes, and (iv) hydride-based inorganic solid electrolytes. From the viewpoint of forming a better interface between the active material and the inorganic solid electrolyte, and further from the viewpoint of forming an active material layer with a high packing density in the pressing method for manufacturing all-solid-state secondary batteries described later, sulfide-based inorganic solid electrolytes are preferred. In the case of a lithium-ion battery in the all-solid-state secondary battery of the present invention, it is preferable that the inorganic solid electrolyte has ionic conductivity for lithium ions.

[0027] (i) Sulfide-based inorganic solid electrolyte The sulfide-based inorganic solid electrolyte is preferably one that contains sulfur atoms, has ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and is also an electronic insulator. The sulfide-based inorganic solid electrolyte is preferably one that contains at least Li, S, and P as elements and has lithium ion conductivity, but may contain other elements other than Li, S, and P as appropriate.

[0028] Examples of sulfide-based inorganic solid electrolytes include lithium-ion conductive inorganic solid electrolytes that satisfy the composition shown in the following formula (S1). L a1 M b1 P c1 S d1 A e1 (S1) In formula (S1), L represents an element selected from Li, Na, and K, with Li being preferred. M represents an element selected from B, Zn, Sn, Si, Cu, Ga, Sb, Al, and Ge. A represents an element selected from I, Br, Cl, and F. a1 to e1 represent the composition ratio of each element, where a1:b1:c1:d1:e1 satisfies 1 to 12:0 to 5:1:2 to 12:0 to 10. a1 is preferably 1 to 9, more preferably 1.5 to 7.5. b1 is preferably 0 to 3, more preferably 0 to 1. d1 is preferably 2.5 to 10, more preferably 3.0 to 8.5. e1 is preferably 0 to 5, more preferably 0 to 3.

[0029] The composition ratio of each element can be controlled by adjusting the amount of raw material compounds used when producing sulfide-based inorganic solid electrolytes, as shown below.

[0030] The sulfide-based inorganic solid electrolyte may be amorphous (glass) or crystalline (glass-ceramic), or partially crystalline. For example, a Li-PS glass containing Li, P, and S, or a Li-PS glass-ceramic containing Li, P, and S can be used. Sulfide-based inorganic solid electrolytes can be produced by the reaction of at least two raw materials from among lithium sulfide (Li2S), phosphorus sulfide (e.g., diphosphorus pentasulfide (P2S5)), elemental phosphorus, elemental 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).

[0031] In Li-PS-based glass and Li-PS-based glass ceramics, the ratio of Li2S to P2S5 is preferably 60:40 to 90:10, more preferably 68:32 to 78:22, in terms of the molar ratio of Li2S:P2S5. By setting the ratio of Li2S to P2S5 within this range, the lithium ion conductivity can be increased. Specifically, the lithium ion conductivity is preferably 1 × 10⁻⁶. -4 S / cm or more, more preferably 1 × 10 -3 It can be S / cm or more. There is no particular upper limit, but 1 × 10 -1 It is practical for the rate to be less than or equal to S / cm.

[0032] Examples of specific sulfide-based inorganic solid electrolytes include the following combinations of raw materials: For example, Li2S-P2S5, Li2S-P2S5-LiCl, Li2S-P2S5-H2S, Li2S-P2S5-H2S-LiCl, Li2S-LiI-P2S5, Li2S-LiI-Li2O-P2S5, Li2S-LiBr-P2S5, Li2S-Li2O-P2S5, Li2S-Li3PO4-P2S5, Li2S-P2S5-P2O5, Li2S-P2S5-SiS2, Li2S-P2S5-SiS2-LiCl, Li2S-P2S5-SnS, and Li2S-P2S5-Al2S3. , 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 These are some examples. However, the mixing ratio of each raw material is not specified. As a method for synthesizing sulfide-based inorganic solid electrolyte materials using such raw material compositions, one example is the amorphous method. Examples of amorphous methods include the mechanical milling method, the solution method, and the melt-quenching method. This is because processing at room temperature is possible, and the manufacturing process can be simplified.

[0033] (ii) Oxide-based inorganic solid electrolyte The oxide-based inorganic solid electrolyte is preferably one that contains oxygen atoms, has the ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and also has electronic insulating properties. Oxide-based inorganic solid electrolytes have an ionic conductivity of 1 × 10⁻⁶. -6 Preferably S / cm or more, 5 × 10 -6 It is more preferable that the S / cm is greater than 1 × 10 -5 It is particularly preferable that the S / cm or higher. There is no particular upper limit, but 1 × 10 -1It is practical that it is below S / cm.

[0034] Specific compound examples include, for example, Li xa La ya TiO3 [xa satisfies 0.3 ≤ xa ≤ 0.7, and ya satisfies 0.3 ≤ ya ≤ 0.7.](LLT); Li xb La yb Zr zb M bb mb O nb (M bb is one or more elements selected from Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In, and Sn. xb satisfies 5 ≤ xb ≤ 10, yb satisfies 1 ≤ yb ≤ 4, zb satisfies 1 ≤ zb ≤ 4, mb satisfies 0 ≤ mb ≤ 2, and nb satisfies 5 ≤ nb ≤ 20.); Li xc B yc M cc zc O nc (M cc is one or more elements selected from C, S, Al, Si, Ga, Ge, In, and Sn. xc satisfies 0 < xc ≤ 5, yc satisfies 0 < yc ≤ 1, zc satisfies 0 < zc ≤ 1, and nc satisfies 0 < nc ≤ 6.); Li xd (Al,Ga) yd (Ti,Ge) zd Si ad P md O nd (xd satisfies 1 ≤ xd ≤ 3, yd satisfies 0 ≤ yd ≤ 1, zd satisfies 0 ≤ zd ≤ 2, ad satisfies 0 ≤ ad ≤ 1, md satisfies 1 ≤ md ≤ 7, and nd satisfies 3 ≤ nd ≤ 13.); Li (3-2xe) M ee xe D ee O(xe represents a number from 0 or more to 0.1 or less, and M ee represents a divalent metal atom. D ee represents a halogen atom or a combination of two or more halogen atoms.); Li xf Si yf O zf (xf satisfies 1 ≤ xf ≤ 5, yf satisfies 0 < yf ≤ 3, and zf satisfies 1 ≤ zf ≤ 10.); Lixg S yg O zg (xg satisfies 1 ≦ xg ≦ 3, yg satisfies 0 < yg ≦ 2, and zg satisfies 1 ≦ zg ≦ 10.); Li3BO3; Li3BO3-Li2SO4; Li2O-B2O3-P2O5; Li2O-SiO2; Li6BaLa2Ta2O 12 ; Li3PO (4-3 / 2w) N w (w is w < 1); Li having a LISICON (Lithium super ionic conductor) type crystal structure 3.5 Zn 0.25 GeO4; La having a perovskite type crystal structure 0.55 Li 0.35 TiO3; LiTi2P3O having a NASICON (Natrium super ionic conductor) type crystal structure 12 ; Li 1+xh+yh (Al, Ga) xh (Ti, Ge) 2-xh Si yh P 3-yh O 12 (xh satisfies 0 ≦ xh ≦ 1 and yh satisfies 0 ≦ yh ≦ 1.); Li7La3Zr2O having a garnet type crystal structure 12 (LLZ), etc. may be mentioned. Also, phosphorus compounds containing Li, P, and O are also desirable. For example, lithium phosphate (Li3PO4); LiPON in which part of the oxygen element of lithium phosphate is substituted with a nitrogen element; LiPOD 1 (D 1 is preferably one or more elements selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Ag, Ta, W, Pt, and Au.) etc. may be mentioned. Furthermore, LiA 1 ON (A 1 is one or more elements selected from Si, B, Ge, Al, C, and Ga.) etc. can also be preferably used.

[0035] (iii) Halide-based inorganic solid electrolytes Halide-based inorganic solid electrolytes are preferably compounds that contain halogen atoms, possess conductivity of metal ions belonging to Group 1 or Group 2 of the periodic table, and have electronic insulating properties. The halogenated inorganic solid electrolyte is not particularly limited, but examples include LiCl, LiBr, LiI, and compounds such as Li3YBr6 and Li3YCl6 as described in ADVANCED MATERIALS, 2018, 30, 1803075. Among these, Li3YBr6 and Li3YCl6 are preferred.

[0036] (iv) Hydride-based inorganic solid electrolytes Hydride-based inorganic solid electrolytes are preferably compounds that contain hydrogen atoms, possess ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and have electronic insulating properties. The hydride-based inorganic solid electrolyte is not particularly limited, but examples include LiBH4, Li4(BH4)3I, and 3LiBH4-LiCl.

[0037] The inorganic solid electrolyte contained in the active material precursor layer of the electrode sheet of the present invention is preferably in particulate form within the active material precursor layer. The shape of the particles is not particularly limited and may be flattened, amorphous, etc., but spherical or granular is preferred. When the inorganic solid electrolyte is in particulate form, the particle size (volume average particle size) of the inorganic solid electrolyte is not particularly limited, but is preferably 0.01 μm or larger, more preferably 0.1 μm or larger, and even more preferably 0.5 μm or larger. As an upper limit, it is preferably 100 μm or less, more preferably 50 μm or less, even more preferably 10 μm or less, even more preferably 5.0 μm or less, and particularly preferably 2.5 μm or less. In particular, when the particle size is in the range of 0.1 to 2.5 μm, the transportability is excellent and the increase in resistance can be effectively suppressed. The particle size of inorganic solid electrolytes is measured using the following procedure: Dilute the inorganic solid electrolyte particles with water (or heptane if the substance is unstable in water) in a 20 mL sample bottle to prepare a 1% by mass dispersion. Irradiate the diluted dispersion sample with 1 kHz ultrasound for 10 minutes and use it for testing immediately thereafter. Using this dispersion sample, acquire data 50 times using a laser diffraction / scattering particle size distribution analyzer LA-920 (product name, manufactured by HORIBA) at a temperature of 25°C with a quartz cell to obtain the volume-average particle size. For other detailed conditions, refer to the Japanese Industrial Standard (JIS) Z 8828:2013 "Particle Size Analysis - Dynamic Light Scattering Method" as needed. Prepare five samples for each level and use their average value.

[0038] The method for adjusting the particle size of the inorganic solid electrolyte used in forming the active material precursor layer is not particularly limited, and known methods can be applied, such as using a conventional pulverizer or classifier. Suitable pulverizers or classifiers include, for example, mortars, ball mills, sand mills, vibrating ball mills, satellite ball mills, planetary ball mills, swirling airflow jet mills, or sieves. Wet pulverization can be performed with the presence of a dispersion medium such as water or methanol during pulverization. Classification is preferable to obtain the desired particle size. Classification is not particularly limited and can be performed using sieves, wind classifiers, etc. Classification can be performed both dry and wet.

[0039] The true density (g / cm³) of the inorganic solid electrolyte contained in the active material precursor layer. 3 ) is not particularly limited and can be set as appropriate. In terms of ease of setting the packing density within the above range, the true density of the inorganic solid electrolyte is 1-3 g / cm³. 3 Preferably, it is 1.5 to 2.5 g / cm³. 3 It is more preferable that this is the case. The true density of the inorganic solid electrolyte shall be the value measured by the gas displacement method described above. Note that the true volume (cm³) of the inorganic solid electrolyte 3 ) is not particularly restricted and can be set as appropriate.

[0040] The inorganic solid electrolyte contained in the active material precursor layer may be one type or two or more types. The content of the inorganic solid electrolyte in the active material precursor layer is not particularly limited and can be determined as appropriate. For example, in the active material precursor layer (100% by mass), the total amount of the inorganic solid electrolyte and the active material described later is preferably 50% by mass or more, more preferably 70% by mass or more, and particularly preferably 90% by mass or more. As an upper limit, from a similar viewpoint, it is preferably 99.9% by mass or less, more preferably 99.5% by mass or less, and particularly preferably 99% by mass or less. In the present invention, when the active material precursor layer contains two or more components such as inorganic solid electrolytes, the content of each component shall be the total content.

[0041] <Active material> The active material precursor layer contains an active material capable of inserting and releasing ions of metals belonging to Group 1 or Group 2 of the periodic table. The active materials include positive electrode active materials and negative electrode active materials, which are described below. The active material layer precursor layer containing the positive electrode active material is sometimes called the positive electrode active material layer precursor layer, and the active material layer precursor layer containing the negative electrode active material is sometimes called the negative electrode active material layer precursor layer.

[0042] (Cathode active material) The positive electrode active material is an active material capable of inserting and releasing ions of metals belonging to Group 1 or Group 2 of the periodic table, and is preferably capable of reversibly inserting and releasing lithium ions. The material is not particularly limited as long as it has the above characteristics, and may be a transition metal oxide or an element that can be compounded with Li, such as sulfur, by disassembling the battery. In particular, it is preferable to use a transition metal oxide as the positive electrode active material, and the transition metal element M a A transition metal oxide having one or more elements selected from Co, Ni, Fe, Mn, Cu, and V is more preferable. b (Elements from Group 1(Ia), Group 2(IIa), Al, Ga, In, Ge, Sn, Pb, Sb, Bi, Si, P, and B, other than lithium, may be mixed.) aIt is preferably 0 to 30 mol% with respect to the amount (100 mol%). The molar ratio of Li / M a is more preferably synthesized by mixing so as to be 0.3 to 2.2. Specific examples of the transition metal oxide include a transition metal oxide having a (MA) layered rock salt structure, a transition metal oxide having a (MB) spinel structure, a (MC) lithium-containing transition metal phosphate compound, a (MD) lithium-containing transition metal halogenated phosphate compound, and a (ME) lithium-containing transition metal silicate compound.

[0043] Specific examples of the transition metal oxide having a (MA) layered rock salt structure include LiCoO2 (lithium cobaltate [LCO]), LiNi2O2 (lithium nickelate), LiNi 0.85 Co 0.10 Al 0.05 O2 (lithium nickel cobalt aluminum oxide [NCA]), LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (lithium nickel manganese cobalt oxide [NMC]) and LiNi 0.5 Mn 0.5 O2 (lithium manganese nickel oxide). Specific examples of the transition metal oxide having a (MB) spinel structure include LiMn2O4 (LMO), LiCoMnO4, Li2FeMn3O8, Li2CuMn3O8, Li2CrMn3O8, and Li2NiMn3O8. Examples of the (MC) lithium-containing transition metal phosphate compound 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 phosphate salts such as Li3V2(PO4)3 (lithium vanadium phosphate). Examples of the (MD) lithium-containing transition metal halogenated phosphate compound include iron phosphate fluoride salts such as Li2FePO4F, manganese phosphate fluoride salts such as Li2MnPO4F, and cobalt phosphate fluoride salts such as Li2CoPO4F. (ME) Examples of the lithium-containing transition metal silicate compound include Li2FeSiO4, Li2MnSiO4, Li2CoSiO4, etc. In the present invention, a transition metal oxide having a (MA) layered rock salt structure is preferred, and LCO or NMC is more preferred.

[0044] The positive electrode active material obtained by the firing method may be used after being washed with water, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent.

[0045] The positive electrode active material contained in the active material layer precursor layer is preferably in a particulate form in the active material layer precursor layer. The shape of the particles is not particularly limited and may be flat, amorphous, etc., but spherical or granular is preferred. When the positive electrode active material is in a particulate form, the particle diameter (volume average particle diameter) of the positive electrode active material is not particularly limited, but for example, 0.1 to 50 μm is preferred, and 0.5 to 10 μm is more preferred. The particle diameter of the positive electrode active material particles can be adjusted in the same manner as the particle diameter of the above inorganic solid electrolyte, and the measurement method thereof can also be measured in the same manner as the particle diameter of the inorganic solid electrolyte.

[0046] The true density (g / cm 3 ) of the positive electrode active material contained in the active material layer precursor layer is not particularly limited and is appropriately set. In terms of being easy to set the filling rate within the above range, the true density of the positive electrode active material is preferably 3 to 7 g / cm 3 , and more preferably 4 to 6 g / cm 3 . The true density of the positive electrode active material is the value measured by the above gas displacement method. The true volume (cm 3 ) of the positive electrode active material is not particularly limited and is appropriately set.

[0047] The positive electrode active material contained in the active material layer precursor layer may be one kind or two or more kinds. The content of the positive electrode active material in the active material layer precursor layer is not particularly limited and is appropriately determined. For example, in the active material layer precursor layer, 10 to 97% by mass is preferred, 30 to 95% by mass is more preferred, 40 to 93% by mass is further preferred, and 50 to 90% by mass is particularly preferred.

[0048] (Negative electrode active material) The negative electrode active material is an active material capable of inserting and releasing ions of metals belonging to Group 1 or Group 2 of the periodic table, and is preferably capable of reversibly inserting and releasing lithium ions. The material is not particularly limited as long as it has the above characteristics, and examples include carbonaceous materials, metal oxides, metal composite oxides, elemental lithium, lithium alloys, and negative electrode active materials that can form alloys with lithium (can be alloyed). Among these, carbonaceous materials, metal composite oxides, or elemental lithium are preferred from the viewpoint of reliability. Active materials that can be alloyed with lithium are preferred in that they enable the production of high-capacity all-solid-state secondary batteries.

[0049] Carbonaceous materials used as negative electrode active materials are materials that consist substantially of carbon. Examples include petroleum pitch, carbon black such as acetylene black (AB), graphite (natural graphite, artificial graphite such as vapor-grown graphite, etc.), and carbonaceous materials obtained by firing 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 plate-shaped graphite. These carbonaceous materials can also be classified into hard carbonaceous materials (also called hard carbon) and graphite-based carbonaceous materials depending on the degree of graphitization. Furthermore, it is preferable that the carbonaceous materials have the interplanar spacing or density and crystallite size described in Japanese Patent Publication No. 62-22066, Japanese Patent Publication No. 2-6856, and Japanese Patent Publication No. 3-45473. The carbonaceous material does not have to be a single material; a mixture of natural graphite and artificial graphite as described in Japanese Patent Publication No. 5-90844, graphite with a coating layer as described in Japanese Patent Publication No. 6-4516, etc., can also be used. As the carbonaceous material, hard carbon or graphite is preferably used, and graphite is more preferably used.

[0050] The oxides of metals or metalloid elements used as negative electrode active materials are not particularly limited as long as they are oxides capable of intercalating and releasing lithium, and include oxides of metal elements (metal oxides), composite oxides of metal elements or composite oxides of metal elements and metalloid elements (collectively referred to as metal composite oxides), and oxides of metalloid elements (metalloid oxides). Among these oxides, amorphous oxides are preferred, and chalcogenides, which are reaction products of metal elements and elements of Group 16 of the periodic table, are also preferred. In the present invention, metalloid elements refer to elements that exhibit properties intermediate between metal elements and nonmetalloid elements, and usually include the six elements boron, silicon, germanium, arsenic, antimony, and tellurium, and further include the three elements selenium, polonium, and astatine. Furthermore, amorphous means having a broad scattering band with peaks in the region of 20° to 40° at 2θ values ​​in X-ray diffraction using CuKα rays, and may have crystalline diffraction lines. Preferably, the strongest intensity of the crystalline diffraction lines observed at 40° to 70° in 2θ values ​​is 100 times or less, more preferably 5 times or less, the intensity of the diffraction line at the peak of the broad scattering band observed at 20° to 40° in 2θ values, and it is particularly preferable that there are no crystalline diffraction lines.

[0051] Among the group of compounds consisting of the amorphous oxides and chalcogenides described above, amorphous oxides of metalloid elements or the chalcogenides described above are more preferred, and oxides (compounds) consisting of one element selected from groups 13(IIIB) to 15(VB) of the periodic table (for example, Al, Ga, Si, Sn, Ge, Pb, Sb, and Bi) or a combination of two or more of these elements, or chalcogenides are particularly preferred. Specific examples of preferred amorphous oxides and chalcogenides include, for example, Ga2O3, GeO, PbO, PbO2, Pb2O3, Pb2O4, Pb3O4, Sb2O3, Sb2O4, Sb2O8Bi2O3, Sb2O8Si2O3, Sb2O5, Bi2O3, Bi2O4, GeS, PbS, PbS2, Sb2S3, or Sb2S5. Suitable negative electrode active materials that can be used in combination with amorphous oxides mainly composed of Sn, Si, and Ge include carbonaceous materials capable of intercalating and / or releasing lithium ions or lithium metal, elemental lithium, lithium alloys, and negative electrode active materials that can be alloyed with lithium.

[0052] From the viewpoint of high current density charge-discharge characteristics, oxides of metals or metalloid elements, particularly metal (composite) oxides and the 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 and the above-mentioned metal (composite) oxide or chalcogenide, more specifically, Li2SnO2. The negative electrode active material, for example, a metal oxide, preferably contains titanium (titanium oxide). Specifically, Li4Ti5O 12 Lithium titanate [LTO] is preferable because it exhibits excellent rapid charge-discharge characteristics due to its small volume fluctuation during lithium ion intercalation and deintercalation, which suppresses electrode degradation and improves the lifespan of lithium-ion secondary batteries.

[0053] The lithium alloy used as the negative electrode active material is not particularly limited as long as it is an alloy commonly used as the negative electrode active material in secondary batteries. For example, lithium aluminum alloy, specifically a lithium aluminum alloy in which lithium is the base metal and 10% by mass of aluminum is added, is an example.

[0054] The negative electrode active material capable of forming an alloy with lithium is not particularly limited as long as it is one that is commonly used as a negative electrode active material in secondary batteries. Examples of such active materials include (negative electrode) active materials (alloys, etc.) having silicon or tin elements, and metals such as Al and In. A negative electrode active material having silicon elements (silicon-containing active material) that enables a higher battery capacity is preferred, and a silicon-containing active material in which the silicon element content is 50 mol% or more of the total constituent elements is more preferred. Generally, negative electrodes containing these negative electrode active materials (for example, Si negative electrodes containing silicon element-containing active materials, Sn negative electrodes containing active materials having tin elements, etc.) can occlude more Li ions than carbon negative electrodes (graphite and acetylene black, etc.). That is, the amount of Li ions occluded per unit mass increases. Therefore, the battery capacity (energy density) can be increased. As a result, there is an advantage that the battery driving time can be lengthened. Examples of the silicon element-containing active material include silicon materials such as Si and SiOx (0 < x ≤ 1), and further silicon-containing alloys containing titanium, vanadium, chromium, manganese, nickel, copper, lanthanum, etc. (for example, LaSi2, VSi2, La-Si, Gd-Si, Ni-Si), or organized active materials (for example, LaSi2 / Si). In addition, active materials containing silicon elements and tin elements such as SnSiO3 and SnSiS3 can also be mentioned. Note that SiOx can be used as a negative electrode active material (semimetal oxide) itself, and can also be used as a negative electrode active material (its precursor material) that can be alloyed with lithium because Si is generated by the operation of the all-solid-state secondary battery. Examples of the negative electrode active material having a tin element include Sn, SnO, SnO2, SnS, SnS2, and further active materials containing the above silicon element and tin element. In addition, composite oxides with lithium oxide, such as Li2SnO2, can also be mentioned.

[0055] In the present invention, the above-mentioned negative electrode active materials can be used without particular limitation, but in terms of battery capacity, a negative electrode active material that can be alloyed with lithium is a preferred embodiment as the negative electrode active material. Among them, the above silicon material or silicon-containing alloy (alloy containing silicon element) is more preferred, and it is even more preferred to include silicon (Si) or a silicon-containing alloy.

[0056] The negative electrode active material contained in the active material precursor layer is preferably in particulate form within the active material precursor layer. The shape of the particles is not particularly limited and may be flattened, amorphous, etc., but spherical or granular is preferred. When the negative electrode active material is in particulate form, the particle diameter (volume average particle diameter) of the negative electrode active material is not particularly limited, but for example, 0.1 to 60 μm is preferred, and 0.5 to 10 μm is more preferred. The particle diameter of the negative electrode active material particles can be adjusted in the same way as the particle diameter of the inorganic solid electrolyte, and the measurement method can also be the same as that for the particle diameter of the inorganic solid electrolyte.

[0057] The true density (g / cm³) of the negative electrode active material contained in the active material precursor layer. 3 ) is not particularly limited and can be set as appropriate. In terms of making it easy to set the packing rate within the above range, the true density of the negative electrode active material is 1-3 g / cm³. 3 Preferably, it is 1.5 to 2.5 g / cm³. 3 It is more preferable that this is the case. The true density of the negative electrode active material shall be the value measured by the gas displacement method described above. Note that the true volume (cm³) of the negative electrode active material 3 ) is not particularly restricted and can be set as appropriate.

[0058] The negative electrode active material contained in the active material precursor layer may be one type or two or more types. The content of the negative electrode active material in the active material precursor layer is not particularly limited and can be determined as appropriate. For example, 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 in the active material precursor layer.

[0059] In this invention, the negative electrode active material layer can also be formed by charging a secondary battery. In this case, instead of the negative electrode active material, ions of metals belonging to Group 1 or Group 2 of the periodic table that are generated in the all-solid-state secondary battery can be used. By combining these ions with electrons and depositing them as a metal, the negative electrode active material layer can be formed.

[0060] The chemical formula of the compound obtained by the above calcination method can be calculated using inductively coupled plasma (ICP) emission spectroscopy as a measurement method, or, as a simpler method, from the mass difference of the powder before and after calcination.

[0061] (Coating of active material) The surfaces of the positive electrode active material and the negative electrode active material may be coated with another metal oxide. 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, lithium niobate compounds, and more specifically, Li4Ti5O 12 Examples include Li2Ti2O5, LiTaO3, LiNbO3, LiAlO2, Li2ZrO3, Li2WO4, Li2TiO3, Li2B4O7, Li3PO4, Li2MoO4, Li3BO3, LiBO2, Li2CO3, Li2SiO3, SiO2, TiO2, ZrO2, Al2O3, B2O3, etc. Furthermore, the electrode surface containing the positive electrode active material or the negative electrode active material may be surface-treated with sulfur or phosphorus. Furthermore, the particle surfaces of the positive electrode active material or negative electrode active material may be surface-treated with active light or an active gas (such as plasma) before or after the above-mentioned surface coating.

[0062] <Polymer Binder> The polymer binder contained in the electrode composition of the present invention contains one or more of the following polymer binders. In the electrode composition described later, the polymer binder is thought to function by dissolving in the dispersion medium or dispersing in particulate form, adsorbing to the active material or inorganic solid electrolyte, or interposing between solid particles, thereby dispersing the active material or inorganic solid electrolyte in the dispersion medium. On the other hand, in the active material layer precursor layer and the active material layer, the polymer binder is thought to function as an adhesive or binder, adsorbing to the active material or inorganic solid electrolyte and causing them to adhere to or bind together. Here, the adsorption of the polymer binder to the active material or inorganic solid electrolyte is not particularly limited, but includes not only physical adsorption but also chemical adsorption (adsorption by chemical bond formation, adsorption by electron transfer, etc.). Furthermore, the polymer binder may also function as a binder that binds the current collector to solid particles. The polymer binder contained in the active material precursor layer may exist in any form within the active material precursor layer, whether precipitated or solidified during the coating and drying of the electrode composition, or in particulate form derived from dispersed particles in the electrode composition.

[0063] - Polymers that form a polymer binder - The polymer forming the polymer binder is not particularly limited, and various polymers can be used. Among these, polymers having at least one bond selected from urethane bonds, urea bonds, amide bonds, imide bonds, and ester bonds, or a polymer chain of carbon-carbon double bonds in its main chain, are preferred. In the present invention, a polymer chain of carbon-carbon double bonds refers to a polymer chain formed by the polymerization of carbon-carbon double bonds (ethylenically unsaturated groups), and specifically refers to a polymer chain obtained by polymerization (homopolymerization or copolymerization) of monomers having carbon-carbon unsaturated bonds.

[0064] In this invention, the main chain of a polymer refers to linear molecular chains in which all other molecular chains constituting the polymer can be considered as branched chains or pendant groups relative to the main chain. Although it depends on the mass-average molecular weight of the molecular chains considered as branched chains or pendant chains, typically the longest chain among the molecular chains constituting the polymer becomes the main chain. However, the terminal groups at the ends of the polymer are not included in the main chain. Furthermore, the side chains of a polymer refer to molecular chains other than the main chain, and include short molecular chains and long molecular chains.

[0065] The above-mentioned bonds are not particularly limited as long as they are contained in the main chain of the polymer, and may be contained in a constituent unit (repeating unit) or / or as bonds connecting different constituent units. Furthermore, the above-mentioned bonds contained in the main chain are not limited to one type, but may be two or more types, preferably 1 to 6 types, and more preferably 1 to 4 types. In this case, the bonding pattern of the main chain is not particularly limited, and may have two or more types of bonds randomly, or it may be a segmented main chain with segments having specific bonds and segments having other bonds.

[0066] The main chain having the above-mentioned bonds is not particularly limited, but a main chain having at least one segment of the above-mentioned bonds is preferred, a main chain made of polyamide, polyurea, polyurethane, or (meth)acrylic polymer is more preferred, and a main chain made of polyurethane or (meth)acrylic polymer is even more preferred.

[0067] Examples of polymers having urethane bonds, urea bonds, amide bonds, imide bonds, or ester bonds in their main chain include sequentially polymerized (polycondensation, polyaddition, or addition-condensation) polymers such as polyurethane, polyurea, polyamide, polyimide, and polyester, or copolymers thereof. The copolymer may be a block copolymer in which each of the above polymers is used as a segment, or a random copolymer in which the constituent components of two or more of the above polymers are randomly bonded together. Examples of polymers having a carbon-carbon double bond polymer chain as the main chain include chain polymers such as fluoropolymers (fluorine-containing polymers), hydrocarbon polymers, vinyl polymers, and (meth)acrylic polymers. The polymerization mode of these chain polymers is not particularly limited and may be block copolymers, alternating copolymers, or random copolymers.

[0068] The polymer forming the binder described above may be one type or two or more types.

[0069] The polymer forming the above binder preferably has components represented by any of the following formulas (1-1) to (1-5), and more preferably has components represented by the following formulas (1-1) or (1-2). [ka]

[0070] In formula (1-1), R 1 R represents a hydrogen atom or an alkyl group (the number of carbon atoms is preferably 1 to 12, more preferably 1 to 6, and even more preferably 1 to 3). 1 The alkyl group that can be selected may have substituents. The substituent is not particularly limited, but examples include substituent Z described later, and groups other than the functional group selected from functional group (a) are preferred, such as halogen atoms.

[0071] R 2 This refers to a group having a hydrocarbon group with 4 or more carbon atoms. In the present invention, a group having a hydrocarbon group is a group consisting of the hydrocarbon group itself (where the hydrocarbon group is R 1 It bonds directly to the carbon atom in the above formula. ) and R 2 A group consisting of a carbon atom in the above formula to which is bonded and a linking group that connects the hydrocarbon group (the hydrocarbon group is R 1 It is bonded to the carbon atom in the above formula via a linking group. ) and are included. A hydrocarbon group is a group composed of carbon atoms and hydrogen atoms, and is usually R 2It is introduced at the end of the molecule. The hydrocarbon group is not particularly limited, but an aliphatic hydrocarbon group is preferred, an aliphatic saturated hydrocarbon group (alkyl group) is more preferred, and a linear or branched alkyl group is even more preferred. The number of carbon atoms in the hydrocarbon group may be 4 or more, preferably 6 or more, more preferably 8 or more, and may also be 10 or more. There is no particular upper limit, but preferably 20 or less, more preferably 18 or less, and even more preferably 14 or less.

[0072] The above linking groups are not particularly limited, but examples include alkylene groups (preferably with 1 to 12 carbon atoms, more preferably 1 to 6, and even more preferably 1 to 3), alkenylene groups (preferably with 2 to 6 carbon atoms, more preferably 2 to 3), arylene groups (preferably with 6 to 24 carbon atoms, more preferably 6 to 10), oxygen atoms, sulfur atoms, and imino groups (-NR). N -:R N The group represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms. Examples include a carbonyl group, a phosphate linking group (-OP(OH)(O)-O-), a phosphonic acid linking group (-P(OH)(O)-O-), or a group relating to a combination thereof. A polyalkylene oxy chain can also be formed by combining an alkylene group and an oxygen atom. Preferred linking groups are those formed by combining an alkylene group, an arylene group, a carbonyl group, an oxygen atom, a sulfur atom, and an imino group, and more preferably a group formed by combining an alkylene group, an arylene group, a carbonyl group, an oxygen atom, and an imino group, such as a -CO-O- group or a -CO-N(R N )-group(R N The above is true. A group containing ) is more preferably a -CO-O- group or a -CO-N(R N )-group(R N The above is true. ) is particularly preferred. The number of atoms constituting the linking group and the number of linked atoms are as described later. However, the above does not apply to the polyalkylene oxy chain constituting the linking group. In the present 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 linked atoms in the linking group is preferably 10 or less, and more preferably 8 or less. The lower limit is 1 or more. The above number of linked atoms refers to the minimum number of atoms that connect predetermined 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 linked atoms is 3. The hydrocarbon group and the linking group may or may not have substituents. Examples of substituents that may be present include substituent Z, which is preferably a functional group other than the functional group selected from functional group (a), and halogen atoms are a suitable example.

[0073] In the above equation (1-1), R 1 The carbon atom adjacent to the carbon atom to which the substituent is bonded has two hydrogen atoms, but in the present invention, it may have one or two substituents. The substituent is not particularly limited, but examples include substituent Z described later, and a group other than the functional group selected from functional group (a) is preferred. The compounds used to derive the constituent components represented by formula (1-1) are not particularly limited, but examples include linear alkyl ester compounds of (meth)acrylate (linear alkyl means an alkyl group having 4 or more carbon atoms).

[0074] 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 of 500 to 200,000. R 3 The ends of the above chain that can be taken as are R 3 The constituent components represented by the above formulas can be appropriately modified to ordinary chemical structures that can be incorporated into them. In each of the above formulas, R 3 Although it is a divalent molecular chain, at least one hydrogen atom may be substituted with -NH-CO-, -CO-, -O-, -NH-, or -N< to form a chain of three or more valents.

[0075] R 3 The polybutadiene and polyisoprene chains that can be used as such include known chains composed of polybutadiene and polyisoprene, respectively, as long as they satisfy the mass-average molecular weight requirement. Both of these polybutadiene and polyisoprene chains are diene polymers having double bonds in the main chain, but in this invention, polymers in which the double bonds have been hydrogenated (reduced) (for example, non-diene polymers that do not have double bonds in the main chain) are also included. In this invention, hydrides of polybutadiene or polyisoprene chains are preferred. The polybutadiene chain and polyisoprene chain, as raw material compounds, preferably have reactive groups at their ends, and more preferably have polymerizable terminal reactive groups. The polymerizable terminal reactive groups, upon polymerization, form the R of each of the above formulas. 3 A group is formed that bonds to the terminal reactive group. Examples of such terminal reactive groups include hydroxyl groups, carboxyl groups, and amino groups, with hydroxyl groups being preferred. Suitable examples of polybutadiene and polyisoprene having terminal reactive groups include the NISSO-PB series (manufactured by Nippon Soda Co., Ltd.), Claysol series (manufactured by Tomoe Engineering Co., Ltd.), PolyVEST-HT series (manufactured by Evonik Corporation), 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.

[0076] R 3 The above-mentioned chains, which can be used as the main chain, preferably have a mass-average molecular weight (polystyrene equivalent) of 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, and more preferably 10,000 or less. The mass-average molecular weight is measured using the method described later for the raw material compound before it is incorporated into the main chain of the polymer.

[0077] The content of any of the components represented by formulas (1-1) to (1-5) in the polymer is not particularly limited, but is preferably 10 to 100 mol%. The content of the component represented by formula (1-1) is more preferably 30 to 98 mol%, and even more preferably 50 to 95 mol%, in terms of dispersion stability, binding properties, etc. The content of any of the components represented by formulas (1-2) to (1-5) is more preferably 30 to 98 mol%, and even more preferably 50 to 95 mol%, in terms of dispersion stability, etc. On the other hand, in terms of improving binding properties, it is preferably 0 to 90 mol%, more preferably 10 to 80 mol%, and even more preferably 20 to 70 mol%.

[0078] (Component having a functional group selected from functional group (a)) The polymer forming the polymer binder preferably contains a component having a functional group selected from the following functional group group (a) as a substituent. The component having the functional group has the function of improving the adsorption of the binder to solid particles and may be any component forming the polymer. The functional group may be incorporated into the main chain of the polymer or into the side chain. When incorporated into the side chain, the functional group may be directly bonded to the main chain or bonded via the linking group. The linking group is not particularly limited, but examples of linking groups described later include <Functional group group (a)> Hydroxyl group, amino group, carboxyl group, sulfo group, phosphate group, phosphonic acid group, sulfanyl group, ether bond (-O-), imino group (=NR, -NR-), ester bond (-CO-O-), amide bond (-CO-NR-), urethane bond (-NR-CO-O-), urea bond (-NR-CO-NR-), heterocyclic group, aryl group, carboxylic anhydride group The amino group, sulfo group, phosphate group (phosphoryl group), heterocyclic group, and aryl group included in functional group (a) are not particularly limited, but are synonymous with the corresponding group of substituent Z described later. However, the number of carbon atoms in the amino group is more preferably 0 to 12, even more preferably 0 to 6, and particularly preferably 0 to 2. The phosphonic acid group is not particularly limited, but examples include phosphonic acid groups with 0 to 20 carbon atoms. When an amino group, ether bond, imino group (-NR-), ester bond, amide bond, urethane bond, urea bond, etc. are included in the ring structure, it is classified as a heterocyclic group. The hydroxyl group, amino group, carboxyl group, sulfo group, phosphate group, phosphonic acid group, and sulfanyl group may form salts. R in each bond represents a hydrogen atom or a substituent, with a hydrogen atom being preferred. The substituent is not particularly limited and can be selected from substituents Z described later, with alkyl groups being preferred.

[0079] The carboxylic acid anhydride group is not particularly limited, but includes groups obtained by removing one or more hydrogen atoms from a carboxylic acid anhydride (for example, a group represented by formula (2a) below), and also the constituent components themselves obtained by copolymerizing polymerizable carboxylic acid anhydrides as copolymerizable compounds (for example, a constituent component represented by formula (2b) below). As for groups obtained by removing one or more hydrogen atoms from a carboxylic acid anhydride, groups obtained by removing one or more hydrogen atoms from a cyclic carboxylic acid anhydride are preferred. Carboxylic acid anhydride groups derived from cyclic carboxylic acid anhydrides also correspond to heterocyclic groups, but in this invention they are classified as carboxylic acid anhydrides. Examples include acyclic carboxylic acid anhydrides such as acetic anhydride, propionic anhydride, and benzoic anhydride, and cyclic carboxylic acid anhydrides such as maleic anhydride, phthalic anhydride, fumaric anhydride, and succinic anhydride. The polymerizable carboxylic acid anhydride is not particularly limited, but includes carboxylic acid anhydrides having an unsaturated bond in the molecule, and is preferably a polymerizable cyclic carboxylic acid anhydride. Specifically, maleic anhydride is an example. Examples of carboxylic acid anhydride groups include the group represented by formula (2a) or the component represented by formula (2b) below, but the present invention is not limited to these. In each formula, * indicates a bond position.

[0080] [ka]

[0081] In sequentially polymerized polymers, ester bonds (-CO-O-), amide bonds (-CO-NR-), urethane bonds (-NR-CO-O-), and urea bonds (-NR-CO-NR-) are represented by being divided into -CO- and -O- groups, -CO and -NR- groups, -NR-CO- and -O- groups, and -NR-CO- and -NR- groups, respectively, when the chemical structure of the polymer is represented by components derived from the raw material compounds. Therefore, in this invention, the components having these bonds are defined as components derived from carboxylic acid compounds or isocyanate compounds, regardless of the polymer's designation, and do not include components derived from polyols or polyamine compounds. Furthermore, in chain polymers, components having ester bonds (excluding ester bonds that form carboxyl groups) or amide bonds mean components in which ester bonds or amide bonds are not directly bonded to atoms constituting the main chain of the chain polymer, or to the main chain of the polymerization chain incorporated into the chain polymer as a branched chain or pendant chain (for example, the polymerization chain of a macromonomer), and do not include, for example, components derived from alkyl (meth)acrylates. In the present invention, it is preferable that amino groups, ether bonds, imino groups, ester bonds, amide bonds, urethane bonds, urea bonds, heterocyclic groups, and aryl groups are incorporated into the branched chain of the polymer. A single component may have one or more functional groups, and if it has two or more, they may or may not be bonded to each other. Furthermore, there is no particular limit to the number of functional groups a single component may have; it may be one or more, and can range from one to four.

[0082] The linking group that connects the functional group to the main chain is not particularly limited, but any linking group other than the following particularly preferred linking groups is R in formula (1-1) above. 2This is synonymous with a linking group in a group having a hydrocarbon group with 4 or more carbon atoms, which can be adopted as such. Particularly preferred linking groups for bonding the functional group and the main chain are the -CO-O- group or the -CO-N(R N )-group(R N As described above, it is a group formed by combining () with an alkylene group or a polyalkylene oxy chain.

[0083] The constituent components having the above-mentioned functional group are not particularly limited as long as they have the above-mentioned functional group, but examples include constituent components obtained by introducing the above-mentioned functional group into a constituent component represented by any of the above-mentioned formulas (1-1) to (1-5), constituent components represented by formula (I-1) or formula (I-2) described later, constituent components derived from a compound represented by formula (I-5) described later, constituent components obtained by introducing the above-mentioned functional group into a constituent component represented by formula (I-3) or formula (I-4) described later, or a constituent component derived from a compound represented by formula (I-6), furthermore, (meth)acrylic compounds (M1) or other polymerizable compounds (M2) described later, constituent components obtained by introducing the above-mentioned functional group into a constituent component represented by any of the above-mentioned formulas (b-1) to (b-3) described later. The compounds that yield the constituent components having the above-mentioned functional groups are not particularly limited, but examples include compounds obtained by introducing the above-mentioned functional groups into (meth)acrylate short-chain alkyl ester compounds (short-chain alkyl means alkyl group with 3 or fewer carbon atoms).

[0084] The content of the component having the above-mentioned functional group in the polymer is not particularly limited. For sequential polymers, the content is preferably 0.01 to 50 mol%, more preferably 0.1 to 50 mol%, and even more preferably 0.3 to 50 mol%, in terms of solid particle dispersion characteristics and binding properties. For chain polymers, the content is preferably 0.01 to 80 mol%, more preferably 0.01 to 70 mol%, even more preferably 0.1 to 50 mol%, particularly preferably 0.3 to 50 mol%, and most preferably 3 to 20 mol%, in terms of solid particle dispersion characteristics and binding properties. For both sequential and chain polymers, the lower limit of the content can be 5 mol% or more, or 20 mol% or more.

[0085] - Sequential polymerization polymer - The step-by-step polymer used to form the binder is preferably a component having a functional group selected from the functional group group (a) or a component represented by any of the above formulas (1-2) to (1-5), and may also have components other than these. Among the components shown below, the component represented by formula (I-1) or formula (I-2), and the component derived from the compound represented by formula (I-5) also correspond to components having a functional group selected from the functional group group (a), but will be explained together with the other components. Examples of other components include one or more (preferably 1 to 8, more preferably 1 to 4) components represented by the following formulas (I-1) or (I-2), and furthermore, components represented by the following formulas (I-3) or (I-4), or components obtained by step-by-step polymerization of a carboxylic acid dianhydride represented by the following formula (I-5) and a diamine compound that leads to the component represented by the following formula (I-6). The combination of each component is appropriately selected depending on the polymer type. When referring to a combination of constituent components, one constituent component means a constituent component represented by one of the following formulas. Even if a combination contains two constituent components represented by one of the following formulas, it will not be interpreted as two constituent components.

[0086] [ka]

[0087] In the formula, R P1 and R P2 Each of these represents a molecular chain with a (mass-average) molecular weight of 20 to 200,000. The molecular weight of this molecular chain cannot be uniquely determined as it depends on its type, etc., but 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 measured for the raw material compound before it is incorporated into the polymer main chain. R P1 and R P2 The molecular chains that can be used are not particularly limited, but hydrocarbon chains, polyalkylene oxide chains, polycarbonate chains, or polyester chains are preferred, hydrocarbon chains or polyalkylene oxide chains are more preferred, and hydrocarbon chains, polyethylene oxide chains, or polypropylene oxide chains are even more preferred.

[0088] R P1 and R P2 A hydrocarbon chain can be defined as a hydrocarbon chain composed of carbon atoms and hydrogen atoms, and more specifically, a structure in which at least two atoms (e.g., hydrogen atoms) or groups (e.g., methyl groups) of a compound composed of carbon atoms and hydrogen atoms have been removed. However, in the present invention, a hydrocarbon chain also includes chains having groups containing oxygen atoms, sulfur atoms, or nitrogen atoms in the chain, such as the hydrocarbon group represented by the following formula (M2). Terminal groups that may be present at the ends of a hydrocarbon chain are not included in the hydrocarbon chain. This hydrocarbon chain may have carbon-carbon unsaturated bonds and may have a ring structure of an aliphatic ring and / or an aromatic ring. That is, a hydrocarbon chain can be any hydrocarbon chain composed of hydrocarbons selected from aliphatic hydrocarbons and aromatic hydrocarbons.

[0089] Such hydrocarbon chains can be any chain that satisfies the above molecular weight requirement, and include both chains consisting of low molecular weight hydrocarbon groups and hydrocarbon chains consisting of hydrocarbon polymers (also called hydrocarbon polymer chains). Low molecular weight hydrocarbon chains are chains consisting of ordinary (non-polymerizable) hydrocarbon groups, such as 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 carbon atoms), arylene groups (preferably with 6 to 22 carbon atoms, more preferably 6 to 14, and even more preferably 6 to 10 carbon atoms), or combinations thereof are preferred. P2 As hydrocarbon groups that can form a low molecular weight hydrocarbon chain, alkylene groups are more preferred, alkylene groups having 2 to 6 carbon atoms are even more preferred, and alkylene groups having 2 or 3 carbon atoms are particularly preferred. This hydrocarbon chain may have polymerization chains (e.g., (meth)acrylic polymers) as substituents.

[0090] The aliphatic hydrocarbon group is not particularly limited and includes, for example, hydrogen-reduced aromatic hydrocarbon groups represented by the following formula (M2), and substructures of known aliphatic diisocyanate compounds (e.g., groups consisting of isophorone). Aromatic hydrocarbon groups include, for example, the hydrocarbon groups possessed by the constituent components of each example listed below, and preferred are arylene groups (for example, groups obtained by removing one or more hydrogen atoms from the aryl group listed in substituent Z below, specifically phenylene groups, torylene groups, or xylylene groups) or hydrocarbon groups represented by the following formula (M2).

[0091] [ka]

[0092] In formula (M2), X represents a single bond, -CH2-, -C(CH3)2-, -SO2-, -S-, -CO-, or -O-, and from the viewpoint of binding properties, -CH2- or -O- is preferred, and -CH2- is more preferred. The alkylene group and methyl group exemplified herein may be substituted with substituent Z, preferably a halogen atom (more preferably a fluorine atom). R M2 ~R M5 Each of these is a hydrogen atom or a substituent, with hydrogen atoms being preferred.M2 ~R M5 The substituents that can be used are not particularly limited, but for example, alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 1 to 20 carbon atoms, -OR M6 ,―N(R M6 )2, -SR M6 (R M6 represents a substituent, preferably an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 10 carbon atoms. Examples include halogen atoms (e.g., fluorine atom, chlorine atom, bromine atom). -N(R M6 )2 may include alkylamino groups (preferably with 1 to 20 carbon atoms, more preferably with 1 to 6 carbon atoms) or arylamino groups (preferably with 6 to 40 carbon atoms, more preferably with 6 to 20 carbon atoms).

[0093] The hydrocarbon polymer chain is a polymer chain formed by the polymerization of polymerizable hydrocarbons (at least two of them), and is not particularly limited as long as it is a chain made of a hydrocarbon polymer with a larger number of carbon atoms than the low molecular weight hydrocarbon chain described above, but is preferably a chain made of a hydrocarbon polymer composed of 30 or more carbon atoms, more preferably 50 or more carbon atoms. The upper limit of the number of carbon atoms that make up the hydrocarbon polymer is not particularly limited and can be, for example, 3,000. The hydrocarbon polymer chain is preferably a chain in which the main chain is made of a hydrocarbon polymer composed of aliphatic hydrocarbons that satisfy the above number of carbon atoms, and is more preferably a chain made of 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-ethylene-butadiene copolymers, isobutylene and isoprene copolymers (preferably butyl rubber (IIR)), ethylene-propylene-diene copolymers, etc. Examples of non-diene polymers include olefin polymers such as ethylene-propylene copolymers and styrene-ethylene-butylene copolymers, as well as hydrogen-reduced products of the above-mentioned diene polymers.

[0094] The hydrocarbons forming the hydrocarbon chain preferably have reactive groups at their ends, and more preferably have terminal reactive groups that can be condensed or polyadded. The terminal reactive groups that can be condensed or polyadded can be used to form the R of each of the above formulas by condensation or polyaddition. P1 or R P2 It forms a group that bonds to the terminal. Examples of such terminal reactive groups include isocinate groups, hydroxyl groups, carboxyl groups, amino groups, and acid anhydrides, with hydroxyl groups being preferred among them. Suitable hydrocarbon polymers having terminal reactive groups include, 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 Corporation), 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), all of which are trade names.

[0095] Examples of polyalkylene oxide chains (polyalkylene oxy chains) include known chains composed of polyalkylene oxy groups. The number of carbon atoms in the alkylene oxy group in the polyalkylene oxy chain is preferably 1 to 10, more preferably 1 to 6, and even more preferably 2 or 3 (polyethylene oxy chain or polypropylene oxy chain). The polyalkylene oxy chain may be a chain composed of one type of alkylene oxy group, or a chain composed of two or more types of alkylene oxy groups (for example, a chain composed of an ethylene oxy group and a propylene oxy group). Examples of polycarbonate chains or polyester chains include known chains made of polycarbonate or polyester. The polyalkylene oxy chain, polycarbonate chain, or polyester chain each preferably has an alkyl group at its terminal (preferably with 1 to 12 carbon atoms, and more preferably with 1 to 6 carbon atoms). R P1 and R P2 The ends of the polyalkylene oxy chain, polycarbonate chain, and polyester chain that can be taken as are R P1 and R P2The components represented by the above formulas can be appropriately modified to have a normal chemical structure that can be incorporated into them. For example, the polyalkylene oxy chain can be modified by removing the terminal oxygen atom to form the R of the above components. P1 or R P2 It will be incorporated as such.

[0096] 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 its terminal. N :R N (These may have a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms.) In each of the above formulas, R P1 and R P2 Although it is a divalent molecular chain, at least one hydrogen atom may be substituted with -NH-CO-, -CO-, -O-, -NH-, or -N< to form a molecular chain of three or more valents.

[0097] R P1 Among the molecular chains described above, hydrocarbon chains are preferred, low molecular weight hydrocarbon chains are more preferred, hydrocarbon chains consisting of aliphatic or aromatic hydrocarbon groups are even more preferred, and hydrocarbon chains consisting of aliphatic hydrocarbon groups are particularly preferred. R P2 Among the molecular chains mentioned above, low molecular weight hydrocarbon chains (more preferably aliphatic hydrocarbon groups), or molecular chains other than low molecular weight hydrocarbon chains (more preferably polyalkylene oxide chains) are preferred.

[0098] Specific examples of the constituent components represented by formula (I-1) are shown below and in the exemplary polymers described later. Furthermore, examples of raw material compounds (diisocyanate compounds) for deriving the constituent components represented by formula (I-1) include the diisocyanate compound represented by formula (M1) and its specific examples, as described in International Publication No. 2018 / 020827, and polymeric 4,4'-diphenylmethane diisocyanate. It should be noted that in the present invention, the constituent components represented by formula (I-1) and the raw material compounds for deriving them are not limited to those described in the specific examples below and in the above-mentioned literature.

[0099] [ka]

[0100] The starting compound (carboxylic acid or its acid chloride, etc.) that leads to the component represented by the above formula (I-2) is not particularly limited, and examples include carboxylic acid or acid chloride compounds and specific examples thereof (e.g., adipic acid or its esterified products) as described in paragraph

[0074] of International Publication No. 2018 / 020827.

[0101] Specific examples of the constituent components represented by formula (I-3) or formula (I-4) are shown below and in the examples. Furthermore, the raw material compounds (diol compounds or diamine compounds) used to derive the constituent components represented by formula (I-3) or formula (I-4) are not particularly limited, and examples include the compounds and specific examples thereof described in International Publication No. 2018 / 020827, as well as dihydroxyoxamide. In this invention, the constituent components represented by formula (I-3) or formula (I-4) and the raw material compounds used to derive them are not limited to those described in the specific examples below, the exemplary polymers described later, and the above-mentioned literature. In the specific examples below, if a component has a repeating structure, the number of repeats is an integer of 1 or more, and is set appropriately within the range that satisfies the molecular weight or number of carbon atoms of the molecular chain.

[0102] [ka]

[0103] In equation (I-5), R P3 The linking group represents an aromatic or aliphatic linking group (tetravalent), and a linking group represented by any of the following formulas (i) to (iix) is preferred.

[0104] [ka]

[0105] In formulas (i) to (iix), X 1 represents a single bond or a divalent linking group. A divalent linking group is preferably an alkylene group having 1 to 6 carbon atoms (e.g., methylene, ethylene, propylene). As propylene, 1,3-hexafluoro-2,2-propanediyl is preferred. L represents -CH2=CH2- or -CH2-. X and R Y Each represents a hydrogen atom or substituent. In each formula, * indicates the bonding site with the carbonyl group in formula (I-5). X and R Y The substituents that can be taken are not particularly limited, and examples of substituent Z described later include alkyl groups (preferably with 1 to 12 carbon atoms, more preferably with 1 to 6 carbon atoms, and still more preferably with 1 to 3 carbon atoms) or aryl groups (preferably with 6 to 22 carbon atoms, more preferably with 6 to 14 carbon atoms, and still more preferably with 6 to 10 carbon atoms).

[0106] The carboxylic acid dianhydride represented by formula (I-5) and the starting compound (diamine compound) from which the constituent component represented by formula (I-6) is derived are not particularly limited, and examples include the compounds described in International Publication No. 2018 / 020827 and International Publication No. 2015 / 046313 and specific examples thereof.

[0107] R P1 , R P2 and R P3 Each of these may have substituents. These substituents are not particularly limited and include, for example, substituent Z described later, or each of the groups included in the above functional group group (a), and R M2 The above substituents that can be adopted are preferably listed.

[0108] If the polymer forming the binder is a stepwise polymer, it may have a component represented by any of the above formulas (1-1) to (1-5), preferably a component having a functional group selected from functional group group (a) (including the component represented by the following formula (I-1)), and may also have a component represented by the above formulas (I-3), (I-4), or (I-5). Examples of the component represented by formula (I-3) include components represented by at least one of the following formulas (I-3A) to (I-3C). The component represented by formula (I-4) is similar to the component represented by formula (I-3), but in each of the following formulas (I-3A) to (I-3C), an oxygen atom is replaced with a nitrogen atom.

[0109] [ka] In equation (I-1), R P1 As stated above, in equation (I-3A), R P2A R represents a chain consisting of low molecular weight hydrocarbon groups (preferably aliphatic hydrocarbon groups). In formula (I-3B), R P2B R represents a polyalkylene oxy chain. In formula (I-3C), R P2C R represents a hydrocarbon polymer chain. P2A A chain consisting of low molecular weight hydrocarbon groups that can be taken as R P2B Polyalkylene oxy chains and R that can be taken as such P2C The hydrocarbon polymer chains that can be used are, respectively, R in formula (I-3) above. P2 This is synonymous with aliphatic hydrocarbon groups, polyalkylene oxy chains, and hydrocarbon polymer chains that can be taken as such, and the preferred ones are also the same.

[0110] The polymer forming the binder (sequentially polymerized polymer) may have components other than those represented by the above formulas. Such components are not particularly limited as long as they can be sequentially polymerized with the raw material compounds that derive the components represented by the above formulas.

[0111] The total content of each component represented by formulas (I-1) to (I-6) in the polymer forming the binder 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, for example, 100 mol% or less, notwithstanding the above 60 mol%. The content of components other than those represented by the above formulas in the polymer forming the binder is not particularly limited, but is preferably 50 mol% or less.

[0112] If the polymer forming the binder has a component represented by any of the above formulas (I-1) to (I-6), the content thereof is not particularly limited and can be appropriately selected and set to the following range, for example. In other words, the content of the component represented by formula (I-1) or formula (I-2), or the component derived from the carboxylic acid dianhydride represented by formula (I-5), in the polymer forming the binder is not particularly limited, but it is preferable that it is the same as the content of the functional group component mentioned above. The content of the constituent component represented by formula (I-3), formula (I-4), or formula (I-6) in the polymer forming the binder is not particularly limited, but is preferably 10 to 85 mol%, more preferably 20 to 70 mol%, and even more preferably 30 to 60 mol%. The content of each component represented by any of the above formulas (I-3A) to (I-3C) is set appropriately, taking into consideration the content of the component represented by the above formula (I-3). For example, the content of the component represented by the above formula (I-3A) is preferably 0 to 85 mol%, and more preferably 10 to 30 mol%. The content of the component represented by the above formula (I-3B) is preferably 0 to 85 mol%, and more preferably 10 to 45 mol%. The content of the component represented by the above formula (I-3C) is preferably 0 to 85 mol%, and more preferably 30 to 60 mol%.

[0113] Furthermore, if the polymer forming the binder has multiple constituent components represented by each formula, the above content of each constituent component shall be the total content.

[0114] The polymers forming the above binder (each component and raw material compound) may have substituents. While there are no particular limitations on substituents, preferred substituents are those selected from the substituent Z listed below.

[0115] The polymer forming the binder described above can be synthesized by selecting raw material compounds according to known methods depending on the type of bonds in the main chain, and then performing polyaddition or condensation polymerization on the raw material compounds. For example, see International Publication No. 2018 / 151118 for synthesis methods. There are no particular limitations on the method of incorporating functional groups. Examples include copolymerizing a compound having a functional group selected from the functional group group (a), using a polymerization initiator having (or producing) the above-mentioned functional group, and utilizing polymer reactions.

[0116] Examples of polymers that can be used to form the above-mentioned binder include polyurethanes, polyureas, polyamides, and polyimides, as described in International Publication No. 2018 / 020827, International Publication No. 2015 / 046313, and Japanese Patent Publication No. 2015-088480.

[0117] - Substituent Z - Alkyl groups (preferably C1-C20 alkyl groups, e.g., methyl, ethyl, isopropyl, t-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.), alkenyl groups (preferably C2-C20 alkenyl groups, e.g., vinyl, allyl, oleyl, etc.), alkynyl groups (preferably C2-C20 alkynyl groups, e.g., ethynyl, butadiinyl, phenylethynyl, etc.), cycloalkyl groups (preferably C3-C20 cycloalkyl groups, e.g., cyclopropyl, cyclopentyl) , cyclohexyl, 4-methylcyclohexyl, etc. In this invention, when we refer to alkyl groups, it usually means including cycloalkyl groups, but here it is described separately.), aryl groups (preferably aryl groups having 6 to 26 carbon atoms, for example, phenyl, 1-naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methylphenyl, etc.), aralkyl groups (preferably aralkyl groups having 7 to 23 carbon atoms, for example, benzyl, phenethyl, etc.), heterocyclic groups (preferably heterocyclic groups having 2 to 20 carbon atoms, more preferably at least one oxygen atom, a sulfur atom, a nitrogen atom) It is a heterocyclic group having a 5 or 6 membered ring. Heterocyclic groups include aromatic heterocyclic groups and aliphatic heterocyclic groups. For example, tetrahydropyran ring group, tetrahydrofuran ring group, 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-oxazolyl, pyrrolidone group, etc.), alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, for example, methoxy, ethoxy, isopropyloxy, benzyloxy, etc.), aryloxy group (preferably an aryloxy group having 6 to 26 carbon atoms, for example, phenoxy, 1-naphthyloxy) (Xy, 3-methylphenoxy, 4-methoxyphenoxy, etc.), heterocyclic oxy groups (groups in which an -O- group is bonded to the above heterocyclic group), alkoxycarbonyl groups (preferably alkoxycarbonyl groups having 2 to 20 carbon atoms, for example, ethoxycarbonyl, 2-ethylhexyloxycarbonyl, dodecyloxycarbonyl, etc.), aryloxycarbonyl groups (preferably aryloxycarbonyl groups having 6 to 26 carbon atoms, for example, phenoxycarbonyl, 1-naphthyloxycarbonyl, 3-methylphenoxycarbonyl, 4-methoxyphenoxycarbonyl, etc.),Heterocyclic oxycarbonyl groups (groups in which an -O-CO- group is bonded to the above heterocyclic group), amino groups (preferably amino groups having 0 to 20 carbon atoms, alkylamino groups, arylamino groups, for example, amino(-NH2), N,N-dimethylamino, N,N-diethylamino, N-ethylamino, anilino, etc.), sulfamoyl groups (preferably sulfamoyl groups having 0 to 20 carbon atoms, for example, N,N-dimethylsulfamoyl, N-phenylsulfamoyl, etc.), acyl groups (alkylcarbonyl groups, alkenylcarbonyl groups, alkynylcarbonyl groups, arylcarbonyl groups) The acyl group includes a heterocyclic carbonyl group, preferably a carbon 1 to 20 acyl group, for example, acetyl, propionyl, butyryl, octanoyl, hexadecanoyl, acryloyl, methacryloyl, crotonoyl, benzoyl, naphthoyl, nicotinoyl, etc., and the acyloxy group includes alkylcarbonyloxy groups, alkenylcarbonyloxy groups, alkynylcarbonyloxy groups, and heterocyclic carbonyloxy groups, preferably a carbon 1 to 20 acyloxy group, for example, acetyloxy, propionyloxy, butyryloxy, octanoyloxy, hexadecanoyl (e.g., noyloxy, acryloyloxy, methacryloyloxy, crotonoyloxynicotinoyloxy), allyloxy group (preferably allyloxy group having 7 to 23 carbon atoms, e.g., benzoyloxy, naphthoyloxy), carbamoyl group (preferably carbamoyl group having 1 to 20 carbon atoms, e.g., N,N-dimethylcarbamoyl, N-phenylcarbamoyl), acylamino group (preferably acylamino group having 1 to 20 carbon atoms, e.g., acetylamino, benzoylamino), alkylthio group (preferably alkylthio group having 1 to 20 carbon atoms) Groups, for example, methylthio, ethylthio, isopropylthio, benzylthio, etc.), arylthio groups (preferably arylthio groups having 6 to 26 carbon atoms, for example, phenylthio, 1-naphthylthio, 3-methylphenylthio, 4-methoxyphenylthio, etc.), heterocyclic thio groups (groups in which an -S- group is bonded to the above heterocyclic group), alkylsulfonyl groups (preferably alkylsulfonyl groups having 1 to 20 carbon atoms, for example, methylsulfonyl, ethylsulfonyl, etc.), arylsulfonyl groups (preferably arylsulfonyl groups having 6 to 22 carbon atoms, for example, benzenesulfonyl, etc.),Alkylsilyl groups (preferably alkylsilyl groups having 1 to 20 carbon atoms, e.g., monomethylsilyl, dimethylsilyl, trimethylsilyl, triethylsilyl, etc.), arylsilyl groups (preferably arylsilyl groups having 6 to 42 carbon atoms, e.g., triphenylsilyl, etc.), alkoxysilyl groups (preferably alkoxysilyl groups having 1 to 20 carbon atoms, e.g., monomethoxysilyl, dimethoxysilyl, trimethoxysilyl, triethoxysilyl, etc.), aryloxysilyl groups (preferably aryloxysilyl groups having 6 to 42 carbon atoms, e.g., triphenyloxysilyl, etc.), phosphoryl groups (preferably phosphate groups having 0 to 20 carbon atoms, e.g., -OP(=O)(R, P 2) A phosphonyl group (preferably a phosphonyl group having 0 to 20 carbon atoms, for example, -P(=O)(R P 2) A phosphenyl group (preferably a phosphenyl group having 0 to 20 carbon atoms, for example, -P(R P 2) A phosphonic acid group (preferably a phosphonic acid group having 0 to 20 carbon atoms, for example, -PO(OR P 2) Examples include sulfo groups (sulfonic acid groups), carboxyl groups, hydroxyl groups, sulfanyl groups, cyano groups, and halogen atoms (e.g., fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc.). P is a hydrogen atom or a substituent (preferably a group selected from substituent Z). Furthermore, each of the groups listed as substituent Z may be further substituted with the substituent Z mentioned above. The alkyl groups, alkylene groups, alkenyl groups, alkenylene groups, alkynyl groups and / or alkynylene groups mentioned above may be cyclic or linear, and may be linear or branched.

[0118] - Chain polymerization polymer - We will now describe chain polymerization polymers, which are polymers that form the above-mentioned binder. The chain polymer preferably has a component having a functional group selected from the functional group group (a) or a component represented by the formula (1-1) described above, more preferably has a component having the above functional group and a component represented by the formula (1-1), and may also have components other than these components. The chain polymer may not have a component having a functional group selected from the functional group group (a) or a component represented by the formula (1-1) described above, and may be a polymer made of other components.

[0119] Examples of fluorine-containing polymers include polytetrafluoroethylene (PTFE), polyvinylidene difluoride (PVdF), copolymers of polyvinylidene difluoride and hexafluoropropylene (PVdF-HFP), and copolymers of polyvinylidene difluoride, hexafluoropropylene, and tetrafluoroethylene (PVdF-HFP-TFE). In PVdF-HFP, the copolymerization ratio [PVdF:HFP] (mass ratio) of PVdF to HFP is not particularly limited, but 9:1 to 5:5 is preferred, and 9:1 to 7:3 is more preferred from the viewpoint of adhesion. In PVdF-HFP-TFE, the copolymerization ratio [PVdF:HFP:TFE] (mass ratio) of PVdF, HFP, and TFE is not particularly limited, but 20 to 60:10 to 40:5 to 30 is preferred, and 25 to 50:10 to 35:10 to 25 is even more preferred.

[0120] Examples of hydrocarbon polymers include polyethylene, polypropylene, natural rubber, polybutadiene, polyisoprene, polystyrene, polystyrene-butadiene copolymer, styrene-based thermoplastic elastomer, polybutylene, acrylonitrile-butadiene copolymer, or hydrogenated polymers thereof. Examples of styrene-based thermoplastic elastomers or their hydrogenated products are not particularly limited, but include styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-isoprene-styrene block copolymer (SIS), hydrogenated SIS, styrene-butadiene-styrene block copolymer (SBS), hydrogenated SBS, styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-butadiene rubber (SBR), hydrogenated styrene-butadiene rubber (HSBR), and random copolymers corresponding to the above block copolymers such as SEBS. In the present invention, hydrocarbon polymers that do not have unsaturated groups (e.g., 1,2-butadiene components) bonded to the main chain are preferred in that they can suppress the formation of chemical crosslinks.

[0121] Examples of vinyl polymers include polymers containing, for example, 50 mol% or more of vinyl monomers other than (meth)acrylic compounds (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. This vinyl polymer may also preferably contain components derived from a (meth)acrylic compound (M1) that forms the (meth)acrylic polymer described later, in addition to components derived from vinyl monomers. The content of components derived from vinyl monomers is preferably the same as the content of components derived from (meth)acrylic compound (M1) in the (meth)acrylic polymer. The content of components derived from (meth)acrylic compound (M1) is not particularly limited as long as it is less than 50 mol% in the polymer, but is preferably 0 to 30 mol%.

[0122] As the (meth)acrylic polymer, a polymer obtained by copolymerizing at least one (meth)acrylic compound (M1) selected from (meth)acrylic acid compounds, (meth)acrylic acid ester compounds, (meth)acrylamide compounds, and (meth)acrylonitrile compounds as another component is preferred. A (meth)acrylic polymer consisting of a copolymer of (meth)acrylic compound (M1) and other polymerizable compounds (M2) is also preferred. Furthermore, a (meth)acrylic polymer having a component derived from a macromonomer as another component is also preferred. The macromonomer is not particularly limited as long as it is a monomer copolymerizable with the (meth)acrylic compound (M1), but examples include (meth)acrylic compounds having the polymerization chain of the above-mentioned chain polymerization polymer. As the chain polymerization polymer that can be taken as the polymerization chain, a (meth)acrylic polymer is preferred. The number-average molecular weight of the macromonomer is not particularly limited, but is preferably 500 to 100,000, and more preferably 2,000 to 20,000. Other polymerizable compounds (M2) are not particularly limited and include vinyl compounds such as styrene compounds, vinylnaphthalene compounds, vinylcarbazole compounds, allyl compounds, vinyl ether compounds, vinyl ester compounds, dialkyl itaconates, and unsaturated carboxylic acid anhydrides, as well as fluorinated products thereof. Examples of vinyl compounds include the "vinyl monomers" described in Japanese Patent Application Publication No. 2015-88486. The (meth)acrylic compound (M1) and other polymerizable compounds (M2) may have substituents. The substituents are not particularly limited as long as they are not functional groups included in the above-mentioned functional group group (a), and preferably include groups selected from substituent Z. The content of components derived from macromonomers in the (meth)acrylic polymer is not particularly limited, but can be, for example, 10 mol% or less. The content of components derived from other polymerizable compounds (M2) in the (meth)acrylic polymer is not particularly limited, but can be, for example, 50 mol% or less.

[0123] As the (meth)acrylic compound (M1) and vinyl compound (M2) that lead to the constituent components of the (meth)acrylic polymer and vinyl polymer, compounds represented by the following formula (b-1) are preferred. This compound is different from the constituent components having the functional groups included in the above-mentioned functional group group (a) and the compounds that lead to the constituent components represented by the above formula (1-1).

[0124] [ka]

[0125] In the formula, R 1 represents a hydrogen atom, a hydroxyl group, a cyano group, a halogen atom, an alkyl group (preferably with 1 to 24 carbon atoms, more preferably with 1 to 12 carbon atoms, and particularly preferably with 1 to 6 carbon atoms), an alkenyl group (preferably with 2 to 24 carbon atoms, more preferably with 2 to 12 carbon atoms, and particularly preferably with 2 to 6 carbon atoms), an alkynyl group (preferably with 2 to 24 carbon atoms, more preferably with 2 to 12 carbon atoms, and particularly preferably with 2 to 6 carbon atoms), or an aryl group (preferably with 6 to 22 carbon atoms, and more preferably with 6 to 14 carbon atoms). Among these, a hydrogen atom or an alkyl group is preferred, and a hydrogen atom or a methyl group is more preferred.

[0126] R 2 R represents a hydrogen atom or substituent. 2 The substituents that can be chosen are not particularly limited, but include alkyl groups (branched chains are also acceptable, but straight chains are preferred), alkenyl groups (2 to 12 carbon atoms are preferred, 2 to 6 carbon atoms are more preferred, and 2 or 3 carbon atoms are particularly preferred), aryl groups (6 to 22 carbon atoms are preferred, and 6 to 14 carbon atoms are more preferred), aralkyl groups (7 to 23 carbon atoms are preferred, and 7 to 15 carbon atoms are more preferred), and cyano groups. The alkyl group preferably has 1 to 3 carbon atoms. The alkyl group may have, for example, a substituent Z other than the functional group included in the above functional group group (a).

[0127] L 1The linking group is not particularly limited, but may include, for example, an alkylene group having 1 to 6 carbon atoms (preferably 1 to 3), an alkenylene group having 2 to 6 carbon atoms (preferably 2 to 3), an arylene group having 6 to 24 carbon atoms (preferably 6 to 10), an oxygen atom, a sulfur atom, or an imino group (-NR). N -:R N As mentioned above, examples include carbonyl groups, phosphate linking groups (-OP(OH)(O)-O-), phosphonic acid linking groups (-P(OH)(O)-O-), or groups related to combinations thereof, such as -CO-O- groups and -CO-N(R N )-group(R N The above is preferred. The above linking group may have any substituents. The number of atoms constituting the linking group and the number of linked atoms are as described later. Examples of arbitrary substituents include the substituent Z, for example, alkyl groups or halogen atoms.

[0128] n is 0 or 1, and 1 is preferred. However, -(L 1 ) n -R 2 If n represents one type of substituent (e.g., an alkyl group), then set n to 0, and R 2 Let this be a substituent (alkyl group).

[0129] As the (meth)acrylic compound (M1) mentioned above, compounds represented by the following formulas (b-2) or (b-3) are also preferred. These compounds are different from the components having functional groups included in the above-mentioned functional group group (a) and the compounds that derive the components represented by the above formula (1-1).

[0130] [ka]

[0131] R 1 , n is equivalent to the above equation (b-1). R 3 R 2 It is synonymous with [the above]. L 2 is a linking group, and the above L 1 It is synonymous with [the above]. L 3 is a linking group, and the above L 1 This is synonymous, but an alkylene group having 1 to 6 carbon atoms (preferably 1 to 3) is preferred. m is an integer between 1 and 200, preferably between 1 and 100, and more preferably between 1 and 50.

[0132] In the above formulas (b-1) to (b-3), the carbon atom that forms the polymerizable group is R 1 Carbon atoms that are not bonded are represented as unsubstituted carbon atoms (H2C=), but they may have substituents. There are no particular restrictions on substituents, but for example, R 1 The above groups can be considered as such. Furthermore, in formulas (b-1) to (b-3), groups that may take substituents, such as alkyl groups, aryl groups, alkylene groups, and arylene groups, may have substituents to the extent that they do not impair the effects of the present invention. The substituents may be any substituents other than the functional groups selected from the functional group group (a), for example, groups selected from substituent Z described later, specifically halogen atoms, etc.

[0133] The (meth)acrylic polymer preferably has components having a functional group selected from the functional group group (a) described above, or components represented by the formula (1-1) described above, and may have components derived from the (meth)acrylic compound (M1), components derived from the vinyl compound (M2), and other components copolymerizable with compounds that lead to these components. Having components represented by the formula (1-1) described above and components having a functional group selected from the functional group group (a) among the (meth)acrylic compound (M1) is preferable in terms of dispersion stability and binding properties.

[0134] The chain polymer (each component and raw material compound) may have substituents. The substituents are not particularly limited, and preferably include groups selected from the substituent Z described above, and groups other than the functional groups included in the functional group group (a) described above are preferred.

[0135] The content of the constituent components in the (meth)acrylic polymer is not particularly limited and can be appropriately selected and set to the following ranges, for example. The content of the constituent components represented by formula (1-1) above and the constituent components having functional groups selected from the functional group group (a) is as described above. The content of the constituent component derived from the (meth)acrylic compound (M1) in the (meth)acrylic polymer is not particularly limited and can be 100 mol%, but is preferably 1 to 90 mol%, more preferably 10 to 80 mol%, and particularly preferably 20 to 70 mol%. The content of the constituent component derived from the vinyl compound (M2) in the (meth)acrylic polymer is not particularly limited, but is preferably 1 to 50 mol%, more preferably 10 to 50 mol%, even more preferably 20 to 50 mol%, and still more preferably 23 to 35 mol%.

[0136] The chain polymer (each component and raw material compound) may have substituents. The substituent is not particularly limited as long as it is a functional group other than those included in the above-mentioned functional group group (a), and preferably a group selected from substituent Z.

[0137] Chain polymers can be synthesized by selecting raw material compounds and polymerizing them using known methods. There are no particular limitations on the method of incorporating functional groups. Examples include copolymerizing a compound having a functional group selected from functional group (a), using a polymerization initiator or chain transfer agent having (or producing) the above-mentioned functional group, utilizing polymer reactions, ene reactions or ene-thiol reactions to double bonds (for example, formed by the dehydrofluoridation reaction of VDF components in the case of fluoropolymers), or ATRP (Atom Transfer Radical Polymerization) polymerization using a copper catalyst. In addition, functional groups can also be introduced by using functional groups present in the main chain, side chains, or terminals of the polymer as reaction sites. For example, a functional group selected from functional group (a) can be introduced by using a compound having a functional group and reacting it with carboxylic acid anhydride groups in the polymer chain in various ways.

[0138] Specific examples of polymers that form polymer binders include those synthesized in the examples below, but the present invention is not limited to these. In each specific example, the number in the lower right corner of the constituent component indicates the content in the polymer, and the unit is mole percent.

[0139] [ka]

[0140] The polymer binder can be selected from an appropriate polymer, for example, a chain polymer is preferred, and a hydrocarbon polymer or (meth)acrylic polymer is more preferred.

[0141] (The physical properties or characteristics of the polymer binder, or the polymer forming this binder) True density (g / cm³) of the polymer binder contained in the active material precursor layer 3 ) is not particularly limited and can be set as appropriate. The true density of the polymer binder is 0.5 to 2.5 g / cm³, which makes it easy to set the filling rate within the above range. 3 Preferably, it is 0.8 to 2.2 g / cm³. 3It is more preferable that this is the case. The true density of the polymer binder shall be the value measured by the gas displacement method described above. Note that the true volume (cm³) of the polymer binder 3 ) is not particularly restricted and can be set as appropriate.

[0142] The polymer binder may be one that dissolves in the dispersion medium described later (also called a soluble binder) or one that exists in particulate form without dissolving (also called a particulate binder). In the present invention, a soluble binder is preferred, and the soluble binder usually exists dissolved in the dispersion medium in the electrode composition described later, although this depends on its content, solubility, the content of the dispersion medium, etc. Here, a polymer binder dissolving in the dispersion medium means, for example, that its solubility is 10% by mass or more in solubility measurements. On the other hand, a polymer binder not dissolving in the dispersion medium (insoluble) means that its solubility is less than 10% by mass in solubility measurements. The particle size of the particulate binder is not particularly limited, but for example, 0.01 to 10 μm is preferred, and 0.05 to 0.5 μm is more preferred. The particle size of the binder particles is the value measured by the same method as the particle size of the inorganic solid electrolyte. The method for measuring solubility is as follows: A specified amount of the polymer binder to be measured is weighed into a glass bottle, and 100 g of the same dispersion medium as that contained in the electrode composition is added thereto. The mixture is stirred at a rotation speed of 80 rpm on a mix rotor at a temperature of 25°C for 24 hours. The transmittance of the resulting mixture after 24 hours of stirring is measured under the following conditions. This test (transmittance measurement) is performed by changing the amount of polymer binder dissolved (the specified amount above), and the upper limit concentration X (mass%) at which the transmittance is 99.8% is defined as the solubility of the polymer binder in the above dispersion medium. <Transmittance measurement conditions> Dynamic light scattering (DLS) measurement Equipment: DLS-8000 DLS measuring device manufactured by Otsuka Electronics Laser wavelength, power output: 488nm / 100mW Sample cell: NMR tube

[0143] The mass average molecular weight of the polymer forming the polymer binder is not particularly limited, but for example, 15,000 or more is preferable, 30,000 or more is more preferable, and 50,000 or more is still more preferable. As the upper limit, 5,000,000 or less is practical, but 4,000,000 or less is preferable, 3,000,000 or less is more preferable, 700,000 or less is still more preferable, 500,000 or less is particularly preferable, and 200,000 or less is most preferable. Incidentally, the mass average molecular weight of the polymer can be appropriately adjusted by changing the types, contents, polymerization time, polymerization temperature, etc. of the polymerization initiator and the like.

[0144] - Measurement of molecular weight - In the present invention, unless otherwise specified, the molecular weight of the polymer, polymer chain, polymerization chain, and macromonomer refers to the mass average molecular weight or number average molecular weight in terms of standard polystyrene by gel permeation chromatography (GPC). As the measurement method, basically, the method set under the following Condition 1 or Condition 2 (preferred) can be mentioned. However, depending on the type of the polymer, polymer chain, or macromonomer, an appropriate eluent may be selected and used as appropriate. (Condition 1) Column: Connect two TOSOH TSKgel Super AWM-H (trade name, manufactured by Tosoh Corporation). Carrier: 10 mM LiBr / N-methylpyrrolidone Measurement temperature: 40°C Carrier flow rate: 1.0 ml / min Sample concentration: 0.1 mass% Detector: RI (refractive index) detector (Condition 2) Column: Use a column connected with TOSOH TSKgel Super HZM-H, TOSOH TSKgel Super HZ4000, and TOSOH TSKgel Super HZ2000 (all trade names, manufactured by Tosoh Corporation). Carrier: Tetrahydrofuran Measurement temperature: 40°C Carrier flow rate: 1.0 ml / min Sample concentration: 0.1 mass% Detector: RI (refractive index) detector

[0145] The moisture concentration of the polymer is preferably 100 ppm or less (by mass). The polymer binder may be one obtained by crystallizing and drying the polymer, or the polymer solution may be used as it is. The polymer forming the polymer binder is preferably amorphous. In the present invention, the polymer being "amorphous" typically means that no endothermic peak due to crystal melting is observed when measured at the glass transition temperature. The polymer forming the polymer binder may be a non-crosslinked polymer or a crosslinked polymer. Also, when the crosslinking of the polymer proceeds by heating or applying a voltage, it may have a molecular weight larger than the above molecular weight. Preferably, the polymer has a mass average molecular weight within the above range at the start of use of the all-solid-state secondary battery.

[0146] The content of the polymer binder in the active material layer precursor layer is 3% by mass or less. Thereby, while maintaining the adhesion and binding of the solid particles, a reduction in the resistance of the all-solid-state secondary battery can be achieved, and the transportability is also excellent. The content of the polymer binder is preferably 0.5 to 2.5% by mass, more preferably 0.7 to 2.0% by mass, and even more preferably 0.8 to 1.5% by mass in terms of achieving both transportability and battery characteristics at a higher level.

[0147] In the present invention, the mass ratio [(mass of inorganic solid electrolyte + mass of active material) / (total mass of polymer binder)] of the total mass of the inorganic solid electrolyte and the active material to the total mass of the polymer binder in 100% by mass of the active material layer precursor layer is preferably in the range of 1,000 to 1. This ratio is more preferably 500 to 2, and even more preferably 100 to 10.

[0148] <Conductive aid> The active material layer precursor layer preferably contains a conductive aid. There are no particular restrictions on the conductive additive, and any commonly known conductive additive can be used. For example, it may be an electronically conductive material such as graphite, artificial graphite, or other graphites; carbon blacks such as acetylene black, Ketjen black, or furnace black; amorphous carbon such as needle coke; carbon fibers such as vapor-grown carbon fibers or carbon nanotubes; or carbonaceous materials such as graphene or fullerene. It may also be a metal powder or metal fiber such as copper or nickel, or a conductive polymer such as polyaniline, polypyrrole, polythiophene, polyacetylene, or polyphenylene derivatives. In this invention, when an active material and a conductive additive are used in combination, the conductive additive is defined as one which does not function as an active material because, when the battery is charged and discharged, insertion and release of ions of metals belonging to Group 1 or Group 2 of the periodic table (preferably Li ions) does not occur. Therefore, among the conductive additives, those which can function as an active material in the active material layer when the battery is charged and discharged are classified as active materials, not conductive additives. Whether or not a conductive additive functions as an active material when the battery is charged and discharged is not unique, but is determined by the combination with the active material.

[0149] The conductive additive contained in the active material precursor layer is preferably in particulate form in the electrode composition. The shape of the particles is not particularly limited and may be flattened, amorphous, etc., but spherical or granular is preferred. When the conductive additive is in particulate form, the particle size (volume average particle size) of the conductive additive is not particularly limited, but for example, 0.02 to 1.0 μm is preferred, and 0.03 to 0.5 μm is more preferred. The particle size of the conductive additive can be adjusted in the same manner as the particle size of the inorganic solid electrolyte, and the measurement method can also be the same as that for the particle size of the inorganic solid electrolyte.

[0150] True density (g / cm³) of conductive additive contained in the active material precursor layer 3 ) is not particularly limited and can be set as appropriate. In terms of making it easy to set the filling rate within the above range, the true density of the conductive additive is 1-3 g / cm³. 3 Preferably, it is 1.5-2 g / cm³. 3It is more preferable that this is the case. The true density of the conductive additive shall be the value measured by the gas displacement method described above. Note that the true volume (cm³) of the conductive additive 3 ) is not particularly restricted and can be set as appropriate.

[0151] The conductive additive contained in the active material precursor layer may be one type or two or more types. The content of the conductive additive in the active material precursor layer is not particularly limited and can be determined as appropriate. For example, it is preferably 10% by mass or less, and more preferably 1.0 to 5.0% by mass, in the active material precursor layer.

[0152] <Lithium salts> The active material precursor layer may also contain a lithium salt (supporting electrolyte). The lithium salt is preferably one commonly used in this type of product, and is not particularly limited; for example, the lithium salt described in paragraphs 0082 to 0085 of Japanese Patent Application Publication No. 2015-088486 is preferred. When the active material precursor layer contains a lithium salt, the lithium salt content is preferably 0.1 parts by mass or more, and more preferably 5 parts by mass or more, per 100 parts by mass of the inorganic solid electrolyte. The upper limit is preferably 50 parts by mass or less, and more preferably 20 parts by mass or less.

[0153] <Dispersant> The active material precursor layer does not need to contain any dispersants other than the polymer binder, as the polymer binder also functions as a dispersant. If the active material precursor layer contains a dispersant other than the polymer binder, a dispersant commonly used in all-solid-state secondary batteries can be appropriately selected and used. Generally, compounds intended for particle adsorption and steric repulsion and / or electrostatic repulsion are preferably used.

[0154] <Other additives> The active material precursor layer may contain, as appropriate, other components besides the above-mentioned components, such as ionic liquids, thickeners, crosslinking agents (those that undergo crosslinking reactions by radical polymerization, condensation polymerization, or ring-opening polymerization), polymerization initiators (those that generate acids or radicals by heat or light), defoaming agents, leveling agents, dehydrating agents, antioxidants, etc. The ionic liquid is included to further improve ionic conductivity, and known ionic liquids can be used without particular limitation. It may also contain polymers other than the polymer that forms the polymer binder described above, commonly used binders, etc.

[0155] [Electrode Sheet] An electrode sheet (sometimes called an electrode sheet for all-solid-state secondary batteries) is a sheet produced by pressing the active material layer precursor layer of the electrode sheet of the present invention, and is suitably used as a material sheet for producing the active material layer of an all-solid-state secondary battery, or a laminate of a current collector and an active material layer. Therefore, the electrode sheet includes various forms depending on its application. For example, it may be a sheet in which the active material layer is formed on a substrate (current collector), or a sheet that does not have a substrate and is formed from the active material layer. An electrode sheet is usually 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 that order, as well as forms having a substrate (current collector), an active material layer, a solid electrolyte layer and an active material layer in that order. In addition, the electrode sheet may have other layers besides the above layers. Examples of other layers include a protective layer (release sheet) and a coating layer. In the present invention, each layer constituting the electrode sheet may be a single-layer structure or a multi-layer structure. The electrode sheet may be a long sheet or a single-sheet sheet.

[0156] In the electrode sheet, the active material layer formed by pressing the active material layer precursor layer is not particularly limited, but it has a packing density of 60% or more, which is normally required for the active material layer of an all-solid-state secondary battery. The packing density of the active material layer is preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more, in terms of battery characteristics (suppression of resistance increase). The upper limit of the packing density is ideally 100%, but in practice it can be 97% or less. The packing density of the active material layer is a value calculated in the same manner as the packing density of the active material layer precursor layer. The film density of the active material layer is not particularly limited and is appropriately determined according to the packing density of the active material precursor layer, the compression ratio by pressing, etc., for example, 1.5 to 4.6 g / cm³. 3 It can be set to 3.0-4.0 g / cm³. 3 Preferably, this would be 3.5-4.0 g / cm³. 3 It is more preferable to do so. When the electrode sheet is a positive electrode sheet, the film density of the positive electrode active material layer is 2.5 to 4.6 g / cm³. 3 Preferably, when the electrode sheet is a negative electrode sheet, the film density of the negative electrode active material layer is 1.2 to 2.2 g / cm³. 3 It is preferable that this be the case.

[0157] Preferably, at least one of the active material layers of the electrode sheet, for example, the positive electrode active material layer, is formed from the active material layer precursor layer of the electrode sheet of the present invention. The content of each component in the active material layer formed in the active material layer precursor layer of the electrode sheet of the present invention is not particularly limited, but preferably it is the same as the content of each component in the active material layer precursor layer. The thickness of each layer constituting the electrode sheet is determined as appropriate and is the same as the thickness of each layer described later in the all-solid-state secondary battery. Furthermore, active material layers that are not formed from a solid electrolyte layer or an active material precursor layer are formed from conventional constituent layer forming materials.

[0158] The electrode sheet has at least one active material layer formed from the electrode sheet of the present invention. By using it as the active material layer of an all-solid-state secondary battery, an all-solid-state secondary battery exhibiting low resistance and excellent battery characteristics can be manufactured even by industrial manufacturing methods. In particular, using an electrode sheet in which the active material layer precursor layer is formed on a current collector allows for strong bonding between the active material layer precursor layer and the current collector, further improving battery characteristics. Furthermore, the electrode consisting of the current collector and the active material layer can be formed in one step, improving productivity. Thus, the electrode sheet of the present invention is suitably used as a sheet-like member for forming the active material layer, preferably an electrode, of an all-solid-state secondary battery (it is incorporated as an active material layer or an electrode).

[0159] [All-solid-state secondary battery] The all-solid-state secondary battery of the present invention comprises a positive electrode active material layer, a negative electrode active material layer facing the positive electrode active material layer, and a solid electrolyte layer disposed between the positive electrode active material layer and the negative electrode active material layer. The all-solid-state secondary battery of the present invention is not particularly limited in its other configurations, as long as it has a solid electrolyte layer between the positive electrode active material layer and the negative electrode active material layer, and for example, known configurations relating to all-solid-state secondary batteries can be adopted. In a preferred all-solid-state secondary battery, the positive electrode active material layer has a positive electrode current collector laminated on the surface opposite to the solid electrolyte layer to constitute the positive electrode, and the negative electrode active material layer has a negative electrode current collector laminated on the surface opposite to the solid electrolyte layer to constitute the negative electrode. In the present invention, each constituent layer (including current collectors, etc.) constituting the all-solid-state secondary battery may have a single-layer structure or a multi-layer structure.

[0160] The all-solid-state secondary battery of the present invention is preferably an all-solid-state secondary battery manufactured by the manufacturing method of the all-solid-state secondary battery described below. For example, in the all-solid-state secondary battery of the present invention, at least one of the positive electrode active material layer and the negative electrode active material layer, preferably the positive electrode active material layer, is an active material layer (an electrode sheet manufactured by pressing the electrode sheet of the present invention) obtained by compressing (pressing) the active material layer precursor layer in the electrode sheet of the present invention to a filling rate of 60% or more. In the present invention, it is also one of the preferred embodiments that both the negative electrode active material layer and the positive electrode active material layer are composed of active material layers obtained by compressing the electrode sheet of the present invention. Further, for the negative electrode (a laminate of a negative electrode current collector and a negative electrode current collector) and the positive electrode (a laminate of a positive electrode current collector and a positive electrode current collector), either one, preferably the positive electrode, is preferably formed of an active material layer obtained by compressing the active material layer precursor layer of the electrode sheet of the present invention, and it is also one of the preferred embodiments that both are formed of active material layers obtained by compressing the active material layer precursor layer of the electrode sheet of the present invention. In the present invention, configuring the active material layer of the all-solid-state secondary battery with an active material layer obtained by compressing the active material layer precursor layer of the electrode sheet of the present invention means that, in addition to the mode in which only the active material layer is composed of an active material layer obtained by compressing the active material layer precursor layer (however, when the electrode sheet has a layer other than the active material layer, the sheet obtained by removing this layer), it includes the mode in which a laminate of the active material layer and the solid electrolyte layer is configured by laminating an active material layer obtained by compressing the active material layer precursor layer and the solid electrolyte layer. The active material layer formed by compressing the active material layer precursor layer of the electrode sheet of the present invention preferably has the same component species and its content as those in the active material layer precursor layer with respect to the component species and its content contained therein. In addition, when the active material layer is not composed of an active material layer obtained by compressing the active material layer precursor layer of the electrode sheet of the present invention, this active material layer can be manufactured using a known material. In the present invention, each constituent layer (including current collectors, etc.) constituting the all-solid-state secondary battery may have a single-layer structure or a multilayer structure.

[0161] [[ID=⑧]]<Positive electrode active material layer and negative electrode active material layer> The negative electrode active material layer and the positive electrode active material layer have the same meaning as the active material layer of the above electrode sheet. The thickness of the negative electrode active material layer and the positive electrode active material layer are not particularly limited. Considering the dimensions of a typical all-solid-state secondary battery, the thickness of each layer is preferably 10 to 1,000 μm, and more preferably 20 μm or more and less than 500 μm. In the all-solid-state secondary battery of the present invention, it is even more preferable that the thickness of at least one of the positive electrode active material layer and the negative electrode active material layer is 50 μm or more and less than 500 μm, and particularly preferable that it is 50 μm or more and 250 μm or less. In the present invention, if the active material layer is composed of an active material layer obtained by compressing the active material layer precursor layer of the electrode sheet of the present invention, a low-resistance all-solid-state secondary battery can be manufactured even by industrial manufacturing methods.

[0162] <Solid electrolyte layer> 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, and more preferably 20 μm or more and less than 500 μm.

[0163] <Current collector> The positive electrode active material layer and the negative electrode active material layer are preferably each provided with a current collector on the side opposite to the solid electrolyte layer. Electron conductors are preferred as such positive electrode and negative electrode current collectors. In this invention, either the positive electrode current collector or the negative electrode current collector, or both together, may be simply referred to as the current collector. As materials for forming the positive electrode current collector, in addition to aluminum, aluminum alloys, stainless steel, nickel, and titanium, materials in which carbon, nickel, titanium, or silver has been treated on the surface of aluminum or stainless steel (with a thin film formed) are preferred, and among these, aluminum and aluminum alloys are more preferred. As materials for forming the negative electrode current collector, in addition to aluminum, copper, copper alloys, stainless steel, nickel, and titanium, materials in which carbon, nickel, titanium, or silver has been treated on the surface of aluminum, copper, copper alloys, or stainless steel are preferred, and aluminum, copper, copper alloys, and stainless steel are more preferred.

[0164] While current collectors are typically made of film sheets, other forms such as nets, punched materials, laths, porous materials, foams, and molded fiber bundles can also be used. The thickness of the current collector is not particularly limited, but 1 to 500 μm is preferred. Furthermore, it is preferable to create an uneven surface on the current collector surface through surface treatment.

[0165] <Other configurations> In the present invention, functional layers or components may be appropriately interposed or arranged between or outside each layer of the negative electrode current collector, negative electrode active material layer, solid electrolyte layer, positive electrode active material layer, and positive electrode current collector.

[0166] <Enclosure> The all-solid-state secondary battery of the present invention may be used as an all-solid-state secondary battery with the above structure in its current form, depending on the application. However, to form a dry cell, it is preferable to enclose it in a suitable housing. The housing may be made of metal or resin (plastic). When using a metal housing, examples include aluminum alloy or stainless steel. It is preferable that the metal housing be divided into a positive electrode housing and a negative electrode housing, and electrically connected to the positive electrode current collector and the negative electrode current collector, respectively. It is preferable that the positive electrode housing and the negative electrode housing are joined together and integrated via a gasket to prevent short circuits.

[0167] A preferred embodiment of the all-solid-state secondary battery of the present invention will be described below with reference to Figure 2, but the present invention is not limited thereto.

[0168] Figure 2 is a schematic cross-sectional view showing an all-solid-state secondary battery (lithium-ion secondary battery) according to a preferred embodiment of the present invention. In this embodiment, the all-solid-state secondary battery 10 has, when viewed from the negative electrode side, a negative electrode current collector 1, a negative electrode active material layer 2, a solid electrolyte layer 3, a positive electrode active material layer 4, and a positive electrode current collector 5 in this order. Each layer is in contact with the others and has an adjacent structure. By adopting such a structure, during charging, electrons (e - ) is supplied, and lithium ions (Li+ ) accumulates. On the other hand, during discharge, lithium ions (Li) accumulated on the negative electrode are released. + The discharge is returned to the positive electrode side, and electrons are supplied to the working part 6. In the illustrated example, a light bulb is used as a model for the working part 6, and it is designed to light up when the discharge occurs.

[0169] When an all-solid-state secondary battery having the layer configuration shown in Figure 2 is placed in a 2032-type coin case, this all-solid-state secondary battery is sometimes referred to as an all-solid-state secondary battery laminate, and the battery made by placing this all-solid-state secondary battery laminate in a 2032-type coin case is sometimes referred to as a (coin-type) all-solid-state secondary battery.

[0170] (Positive electrode active material layer and negative electrode active material layer) In the all-solid-state secondary battery 10, both the positive electrode active material layer and the negative electrode active material layer are composed of an active material layer obtained by compressing the active material layer precursor layer of the electrode sheet of the present invention. Preferably, the positive electrode, which is formed by laminating the positive electrode active material layer and the positive electrode current collector, and the negative electrode, which is formed by laminating the negative electrode active material layer and the negative electrode current collector, are composed of an active material layer obtained by compressing the active material layer precursor layer of the electrode sheet of the present invention, to which the current collector is applied as a base material. The positive electrode active material layer is synonymous with the positive electrode active material layer of the electrode sheet described above, and contains an inorganic solid electrolyte having conductivity of metal ions belonging to Group 1 or Group 2 of the periodic table, a positive electrode active material, a polymer binder, and any of the above-mentioned components, etc., to the extent that they do not impair the effects of the present invention. The negative electrode active material layer is synonymous with the negative electrode active material layer of the electrode sheet described above, and contains an inorganic solid electrolyte having conductivity of metal ions belonging to Group 1 or Group 2 of the periodic table, a negative electrode active material, a polymer binder, and any of the above-mentioned components, etc., within a 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 may be a lithium metal layer. Examples of the lithium metal layer include a layer formed by depositing or molding lithium metal powder, lithium foil, and lithium vapor-deposited film. The thickness of the lithium metal layer can be, for example, 1 to 500 μm, regardless of the thickness of the negative electrode active material layer described above.

[0171] (Solid electrolyte layer) The solid electrolyte layer can be any of those used in conventional all-solid-state secondary batteries without any particular limitations. This solid electrolyte layer contains an inorganic solid electrolyte having the conductivity of metal ions belonging to Group 1 or Group 2 of the periodic table, and optionally any of the above-mentioned components, and usually does not contain an active material.

[0172] Each component contained in the positive electrode active material layer 4, the solid electrolyte layer 3, and the negative electrode active material layer 2, particularly the inorganic solid electrolyte, the conductive additive, and the polymer binder, may be of the same type or different types.

[0173] (Current collector) The positive electrode current collector 5 and the negative electrode current collector 1 are as described above.

[0174] <Applications of all-solid-state rechargeable batteries> The all-solid-state secondary battery of the present invention can be applied to a variety of uses. There are no particular limitations on the applications, but examples of applications when mounted on electronic devices include laptop computers, pen-input computers, mobile computers, e-book players, mobile phones, cordless phone handsets, pagers, handheld terminals, portable fax machines, portable copiers, portable printers, headphone stereos, video cameras, LCD televisions, handheld vacuum cleaners, portable CDs, MiniDiscs, electric shavers, transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, and backup power supplies. Other consumer applications include automobiles (electric vehicles, etc.), electric vehicles, motors, lighting fixtures, toys, game consoles, road conditioners, clocks, strobes, cameras, and medical devices (pacemakers, hearing aids, shoulder massagers, etc.). Furthermore, it can be used for various military and space applications. It can also be combined with solar cells.

[0175] [Manufacturing method for electrode sheets] The method for manufacturing the electrode sheet of the present invention is not particularly limited as long as it is a method that can form an active material layer precursor layer by setting the polymer binder content and the packing rate of the active material layer precursor layer within the above range. Preferably, when forming an active material layer precursor layer by coating and drying an electrode composition containing an inorganic solid electrolyte, an active material, a polymer binder, and a dispersion medium onto a substrate, the method includes the steps of preparing the electrode composition by setting the solid content of the polymer binder to 3% by mass or less and setting the packing rate of the active material layer precursor layer to 35-50% (hereinafter referred to as the electrode sheet manufacturing method of the present invention). In the present invention, if the active material layer precursor layer formed by coating and drying the electrode composition has a packing rate of 35-50%, the electrode sheet manufacturing method of the present invention only needs to include the step of preparing the electrode composition by setting the solid content of the polymer binder to 3% by mass or less when forming the active material layer precursor layer. The electrode sheet of the present invention has excellent transportability and can also be manufactured by applying industrial manufacturing methods.

[0176] <Preparation of electrode composition> In manufacturing electrode sheets, the electrode composition is first prepared. This electrode composition contains an inorganic solid electrolyte, an active material, a polymer binder, and a dispersion medium, preferably a conductive additive, and further optionally contains the aforementioned lithium salt, dispersant, and other additives.

[0177] The electrode composition is preferably a slurry in which an inorganic solid electrolyte, an active material, etc., is dispersed in a dispersion medium. The electrode composition is preferably a non-aqueous composition. In the present invention, a non-aqueous composition includes not only a form that does not contain water, but also a form in which the water content (also called water content) is preferably 500 ppm or less. In a non-aqueous composition, the water content is more preferably 200 ppm or less, even more preferably 100 ppm or less, and particularly preferably 50 ppm or less. If the electrode composition is a non-aqueous composition, the deterioration of the inorganic solid electrolyte can be suppressed. The water content refers to the amount of water contained in the electrode composition (mass ratio to the electrode composition), and specifically, it is the value measured by filtering through a 0.02 μm membrane filter and using Karl Fischer titration.

[0178] The components of the electrode composition other than the dispersion medium are as described above, and the content of each component in 100% by mass of the solid content of the electrode composition is the same as the content in the active material precursor layer described above. In particular, the content of the polymer binder is set to 3% by mass or less in 100% by mass of the solid content of the electrode composition. In this invention, solid content (solid components) refers to components that do not volatilize or evaporate when the electrode composition is dried at 150°C for 6 hours under a pressure of 1 mmHg and a nitrogen atmosphere. Typically, it refers to components other than the dispersion medium described later. Furthermore, the content in the total solid content refers to the content in 100% by mass of the total mass of solid content.

[0179] (dispersion medium) The dispersion medium contained in the electrode composition can be any organic compound that is liquid in the operating environment, such as various organic solvents, specifically alcohol compounds, ether compounds, amide compounds, amine compounds, ketone compounds, aromatic compounds, aliphatic compounds, nitrile compounds, ester compounds, etc. The dispersion medium can be either a nonpolar dispersion medium (hydrophobic dispersion medium) or a polar dispersion medium (hydrophilic dispersion medium), but a nonpolar dispersion medium is preferred because it can exhibit excellent dispersion characteristics. A nonpolar dispersion medium generally refers to a medium with low affinity for water, and in the present invention, examples include ester compounds, ketone compounds, ether compounds, aromatic compounds, aliphatic compounds, and the like.

[0180] Examples of alcohol compounds include methyl alcohol, ethyl alcohol, 1-propyl alcohol, 2-propyl alcohol, 2-butanol, ethylene glycol, propylene glycol, glycerin, 1,6-hexanediol, cyclohexanediol, sorbitol, xylitol, 2-methyl-2,4-pentanediol, 1,3-butanediol, and 1,4-butanediol.

[0181] 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, dioxane (including 1,2-, 1,3-, and 1,4- isomers), etc.).

[0182] Examples of amide compounds include N,N-dimethylformamide, N-methyl-2-pyrrolidone, 2-pyrrolidinone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, formamide, N-methylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropanamide, and hexamethylphosphoric triamide.

[0183] Examples of amine compounds include triethylamine, diisopropylethylamine, and tributylamine. Examples of ketone compounds include acetone, methyl ethyl ketone, methyl isobutyl ketone (MIBK), cyclopentanone, cyclohexanone, cycloheptanone, dipropyl ketone, dibutyl ketone, diisopropyl ketone, diisobutyl ketone (DIBK), isobutylpropyl ketone, sec-butylpropyl ketone, pentylpropyl ketone, and butylpropyl ketone. Examples of aromatic compounds include benzene, toluene, xylene, and perfluorotoluene. Examples of aliphatic compounds include hexane, heptane, octane, nonane, decane, dodecane, cyclohexane, methylcyclohexane, ethylcyclohexane, cycloheptane, cyclooctane, decalin, paraffin, gasoline, naphtha, kerosene, and diesel fuel. Examples of nitrile compounds include acetonitrile, propionitrile, and isobutyronitrile. Examples of ester compounds include ethyl acetate, propyl acetate, butyl acetate, ethyl butyrate, propyl butyrate, isopropyl butyrate, butyl butyrate, isobutyl butyrate, butyl pentanoate, pentyl pentanoate, ethyl isobutyrate, propyl isobutyrate, isopropyl isobutyrate, isobutyl isobutyrate, propyl pivalate, isopropyl pivalate, butyl pivalate, and isobutyl pivalate.

[0184] In the present 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.

[0185] 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 particularly preferably 7 to 12.

[0186] The boiling point of the dispersion medium at normal pressure (1 atmosphere) is not particularly limited, but is preferably 90°C or higher, and more preferably 120°C or higher. The upper limit is preferably 230°C or lower, and more preferably 200°C or lower.

[0187] The electrode composition of the present invention may contain one or more dispersion media. Examples of compositions containing two or more dispersion media include mixed xylene (a mixture of o-xylene, p-xylene, m-xylene, and ethylbenzene). The content of the dispersion medium in the electrode composition is not particularly limited and can be set as appropriate. For example, 20 to 80% by mass is preferred, 30 to 70% by mass is more preferred, and 40 to 60% by mass is particularly preferred in the electrode composition.

[0188] (Preparation of electrode composition) Electrode compositions can be prepared by conventional methods. For example, an inorganic solid electrolyte, an active material, a polymer binder, and a dispersion medium, preferably a conductive additive, and optionally a lithium salt, a dispersant, and other components, can be mixed using various commonly used mixers to prepare a mixture, preferably a slurry. In this case, the polymer binder content is set to 3% by mass or less of 100% by mass of the solid content of the electrode composition. The method of mixing the above components is not particularly limited; the components may be mixed all at once or sequentially. In the present invention, it is preferable to prepare an electrode composition by mixing an active material, preferably a conductive additive, and a dispersion medium into a solid electrolyte composition prepared by mixing an inorganic solid electrolyte, a polymer binder, and a dispersion medium. In this mixing method, the amount of each component used is appropriately set considering the content of each component in the target electrode composition, for example, within the same range as the content of each component in 100% by mass of solids in the electrode composition. The dispersion medium used in the preparation of each composition is appropriately set considering the content of the dispersion medium in the electrode composition, etc. In this preparation method, if lithium salts, dispersants, and other additives are used, these components may be mixed in any of the steps.

[0189] The mixing method and mixing conditions in the preparation of each composition are not particularly limited and can be set as appropriate. For example, in each mixing method, the mixing order of each component may be all at once or sequentially. Furthermore, the mixing method can be carried out using known mixers such as ball mills, bead mills, planetary mixers, blade mixers, roll mills, kneaders, disc mills, revolving mixers, and narrow-gap dispersers. As for the mixing conditions, for example, the mixing temperature can be set to 10 to 60°C, the rotation speed of the revolving mixer can be set to 10 to 700 rpm (rotations per minute), and the mixing time can be set to 5 minutes to 5 hours. When using a ball mill as the mixer, it is preferable to set the rotation speed to 50 to 700 rpm and the mixing time to 5 minutes to 24 hours, preferably 5 to 60 minutes, at the above mixing temperature. Furthermore, the mixing process in this step can be carried out in multiple stages.

[0190] (Application and drying of electrode composition) In the electrode sheet manufacturing method of the present invention, preferably, the prepared electrode composition is applied to the surface of a substrate (which may have other layers in between) and dried (film-formed) to form a coated and dried layer of the electrode composition. Here, the coated and dried layer refers to a layer formed by applying the electrode composition and drying the dispersion medium (i.e., a layer made using the electrode composition, with the dispersion medium removed from the electrode composition). The coated and dried layer may contain residual dispersion medium as long as it does not impair the effects of the present invention, and the residual amount can be, for example, 3% by mass or less in the coated and dried layer. In the electrode sheet manufacturing method of the present invention, the coated and dried film of the electrode composition may be used as an active material layer precursor layer as is, or it may be a layer subjected to a normally performed treatment, for example, the coated and dried film may be pressurized to a extent that does not deviate from the packing ratio to form an active material layer precursor layer.

[0191] The method for applying the electrode composition is not particularly limited and can be selected as appropriate. Examples of wet coating methods include coating (preferably wet coating), spray coating, spin coating, dip coating, slit coating, stripe coating, and bar coating. The coated electrode composition is subjected to a drying (heat treatment) process. The drying temperature is not particularly limited as long as the dispersion medium is removed, and is set appropriately 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, resulting in a solid state (coated and dried layer). This is also preferable because it avoids damaging the individual components of the electrode sheet by not raising the temperature too high. The drying time is determined appropriately according to the drying temperature, etc., and is not particularly limited. For example, it can be 0.1 to 5 hours, and preferably 0.2 to 1 hour.

[0192] After applying the electrode composition, the coated and dried layer can be pressurized within a range that does not deviate from the packing ratio. Examples of pressurizing methods include hydraulic cylinder presses. The pressurizing pressure is not particularly limited and can be set appropriately considering the packing ratio of the active material layer and precursor layer. The pressurizing time can be short (e.g., within a few hours) with high pressure, or long (more than a day). The pressurizing pressure may be uniform or varied across the pressed area of ​​the coated and dried layer. The pressurizing pressure can also be varied according to the area or film thickness of the pressed area. Furthermore, the same area can be subjected to different pressures in stages. The pressed surface may be smooth or roughened. The above pressing may be performed under heating, but it is preferable to perform it without heating, for example, at an ambient temperature of 0 to 50°C.

[0193] Furthermore, the coated electrode composition may be heated simultaneously with pressurization. The heating temperature is not particularly limited, but is generally in the range of 30 to 300°C. Pressing can also be performed at a temperature higher than the glass transition temperature of the inorganic solid electrolyte. It can also be performed at a temperature higher than the glass transition temperature of the polymer constituting the polymer binder. However, generally, the temperature should not exceed the melting point of the polymer. Pressurization may be performed with the coating solvent or dispersion medium pre-dried, or with residual solvent or dispersion medium. The electrode composition may be coated, dried, and pressed simultaneously and / or sequentially.

[0194] The atmosphere for manufacturing electrode sheets is not particularly limited and may be any of the following: open air, dry air (dew point below -20°C), or in an inert gas (e.g., argon, helium, or nitrogen). Since inorganic solid electrolytes readily react with moisture, dry air or an inert gas is preferred.

[0195] - Process (operation) to set the filling rate to 35-50% - In the electrode sheet manufacturing method of the present invention, a step (operation) is performed to set the packing rate of the formed active material layer precursor to 35-50%. However, if the active material layer precursor formed by coating and drying the electrode composition has a packing rate of 35-50%, it is not necessary to perform the step (operation) of setting the packing rate of the active material layer precursor shown below. The process of setting the packing ratio includes steps to adjust the film density or true density, for example, steps to change each component, especially the type, particle size or content of solid particles, as well as the solid content concentration or drying conditions of the electrode composition, the thickness of the coated and dried layer, and further steps to mix in a material that decomposes and volatilizes when heat is applied, and then decompose and volatilize this material after drying and removing the dispersion medium.

[0196] Specifically, reducing the true density of solid particles such as inorganic solid electrolytes, active materials, polymer binders, and conductive additives increases the packing efficiency, and it is preferable to set the true density of each solid particle within the range described above. On the other hand, reducing the particle size of the solid particles tends to decrease the packing efficiency. Furthermore, increasing the solid content concentration of the electrode composition (decreasing the content of the dispersion medium) tends to reduce the packing density. For example, if the solid content concentration is set to, for example, 60% by mass or more, preferably 65% ​​by mass or more, within the range described above, the packing density can be set to 50% or less. Furthermore, regarding the drying conditions of the electrode composition, setting them to conditions that allow for rapid drying tends to result in a smaller packing density. For example, shortening the drying time can reduce the packing density; specifically, within the above drying time range, it is good to set it to 2 hours or less, and preferably 1 hour or less. Also, increasing the drying temperature can reduce the packing density; specifically, within the above drying temperature range, it is good to set it to 80°C or higher, preferably 100°C or higher, more preferably 110°C or higher, and 120°C or higher allows the packing density to be reduced within the above range, enabling high transportability while maintaining low resistance.

[0197] The packing density can also be set by changing the type or properties of the polymer binder. For example, changing the type of polymer forming the polymer binder from one that dissolves in the dispersion medium to a dispersed particulate form tends to increase the packing density. Also, reducing the particle size of the particulate polymer binder tends to increase the packing density. Furthermore, weakening the interaction (adsorption) of the polymer binder with solid particles, for example by reducing the content of the functional group component in the polymer forming the polymer binder, tends to decrease the packing density. Specifically, if the content of the functional group component is set to 3-20 mol% within the above range, it becomes easier to set the packing density to 35-50% or less, especially for chain polymers.

[0198] - Steps (operations) to set the membrane density - In the electrode sheet manufacturing method of the present invention, in addition to the step (operation) of setting the packing ratio, a step of setting the film density of the active material layer precursor layer may also be performed. However, if the active material layer precursor layer formed by coating and drying the electrode composition or by the step of setting the packing ratio has a film density within the above range, it is not necessary to perform the step (operation) of setting the film density. The process of setting the film density is similar to the process of adjusting the film density described above. For example, it may involve changing each component, especially the type, particle size, or content of solid particles, as well as the solid content concentration or drying conditions of the electrode composition, the thickness of the coated and dried layer, and further, mixing in a material that decomposes and volatilizes when heat is applied, and then decomposing and volatilizing this material after drying and removing the dispersion medium.

[0199] Specifically, reducing the true density of solid particles such as inorganic solid electrolytes, active materials, polymer binders, and conductive additives increases the film density, and it is preferable to set the true density of each solid particle within the ranges mentioned above. On the other hand, reducing the particle size of the solid particles tends to decrease the film density. Furthermore, increasing the solid content concentration of the electrode composition (decreasing the content of the dispersion medium) tends to decrease the film density. For example, if the solid content concentration is set to, for example, 60% by mass or more, preferably 65% ​​by mass or more, within the range described above, the film density will be 0.8 to 2.2 g / cm³. 3 Preferably, 1.4-2.0 g / cm³ 3 The following settings are available. Furthermore, regarding the drying conditions of the electrode composition, setting the conditions to allow for rapid drying tends to result in lower film density. For example, shortening the drying time can reduce film density; specifically, within the above drying time range, it is preferable to set it to 2 hours or less, and preferably 1 hour or less. Also, increasing the drying temperature can reduce film density; specifically, within the above drying temperature range, it is preferable to set it to 80°C or higher, preferably 100°C or higher, more preferably 110°C or higher, and 120°C or higher allows the film density to be reduced within the above range, enabling high transportability while maintaining low resistance.

[0200] The film density can also be set by changing the type or properties of the polymer binder. For example, changing the type of polymer forming the polymer binder from one that dissolves in the dispersion medium to a dispersed particulate form tends to increase the film density. Also, reducing the particle size of the particulate polymer binder tends to increase the film density. Furthermore, weakening the interaction (adsorption) of the polymer binder to solid particles, for example by reducing the content of the functional group component in the polymer forming the polymer binder, tends to decrease the film density. Specifically, if the content of the functional group component is 3 to 20 mol% within the above range, the film density will be 0.8 to 2.2 g / cm³. 3 Preferably, 1.4-2.0 g / cm³ 3 The following settings are available.

[0201] The electrode sheet manufacturing method of the present invention described above makes it possible to manufacture an electrode sheet having an active material precursor layer that satisfies the packing ratio and, furthermore, the film density.

[0202] [Method for manufacturing electrode sheets] The electrode sheet can be manufactured by a method of forming an active material layer by pressing the active material layer precursor layer of the electrode sheet of the present invention (hereinafter sometimes referred to as the electrode sheet manufacturing method of the present invention). The active material precursor layer is pressed in the thickness direction of the active material precursor layer. The method of pressing the active material precursor layer can be any conventional pressing method without particular limitations, such as using a hydraulic cylinder press. The applied pressure is not particularly limited as long as it can increase the filling rate of the active material layer to 60% or more, and is set to an appropriate pressure considering the filling rate or thickness of the active material precursor layer, as well as the damage to the solid particle surface. For example, it is preferably 5 to 1500 MPa, more preferably 50 to 1000 MPa, and even more preferably 100 to 600 MPa. In the electrode sheet manufacturing method of the present invention, heating may be performed simultaneously with the pressing described above. The heating method and conditions are not particularly limited, and the heating method and conditions described above, which are performed simultaneously with the pressurization of the coated electrode composition, can be applied. The atmosphere in which the electrode sheet manufacturing method is carried out is not particularly limited and can be the same as the atmosphere used for manufacturing electrode sheets.

[0203] When the electrode sheet has a solid electrolyte layer, it can be manufactured by pressing the solid electrolyte layer or a solid electrolyte layer forming material on top of the electrode sheet of the present invention. The electrode sheet manufacturing method of the present invention described above makes it possible to manufacture an electrode sheet having an active material layer that is a pressurized layer of the active material layer precursor layer and has an active material layer that satisfies a packing ratio of 60% or more.

[0204] [Manufacturing method for all-solid-state secondary batteries] All-solid-state secondary batteries can be manufactured by forming an active material layer or electrodes using the electrode sheet of the present invention or the above-mentioned electrode sheet. In the manufacture of all-solid-state secondary batteries, a solid electrolyte layer, a solid electrolyte sheet, or a solid electrolyte layer forming material is prepared. A solid electrolyte layer or solid electrolyte sheet can be manufactured by forming a film of an inorganic solid electrolyte-containing composition on a substrate. The inorganic solid electrolyte-containing composition can be any commonly used composition without particular limitations. For example, a composition containing the above-mentioned inorganic solid electrolyte, polymer binder, and dispersion medium, and further containing a conductive additive, lithium salt, dispersant, and other additives as appropriate, is a suitable choice. The film-forming method and conditions are also not particularly limited and can be applied as appropriate. A solid electrolyte layer or solid electrolyte sheet can also be manufactured by pressure molding a powder mixture without a dispersion medium using a conventional method. The solid electrolyte layer forming material can be any material capable of forming a solid electrolyte layer, and examples include the inorganic solid electrolyte mentioned above, and materials (usually solid compositions) that optionally contain a polymer binder, a conductive additive, a lithium salt, a dispersant, other additives, etc.

[0205] <Method for manufacturing an all-solid-state secondary battery using the electrode sheet of the present invention> The method for manufacturing an all-solid-state secondary battery using the electrode sheet of the present invention (sometimes referred to as the battery manufacturing method of the present invention) is a method of forming an active material layer or electrode (a laminate of a current collector and an active material layer) by pressing the electrode sheet of the present invention and a solid electrolyte layer or solid electrolyte layer forming material in a stacked state. Here, when forming one of the active material layers with the electrode sheet of the present invention, the electrode sheet of the present invention and the solid electrolyte layer or solid electrolyte layer forming material are stacked. On the other hand, when forming both active material layers with the electrode sheet of the present invention, the electrode sheet of the present invention and the solid electrolyte layer or solid electrolyte layer forming material are stacked and the solid electrolyte layer or solid electrolyte layer forming material is placed between the active material layer precursor layers of the two electrode sheets of the present invention. In the battery manufacturing method of the present invention, the active material layer precursor layer in the electrode sheet of the present invention is pressed in the stacked state described above until the filling rate is usually 60% or more. This pressing is performed collectively (integrally) in the direction in which the active material layer precursor layer is stacked together with the solid electrolyte layer or solid electrolyte layer forming material (the thickness direction of the active material layer precursor layer) while the solid electrolyte layer is stacked on the active material layer precursor layer or the solid electrolyte layer forming material is placed on top of it. The pressing method and conditions are not particularly limited, but for example, the method and conditions described in the method and conditions for pressing the active material layer precursor layer in the electrode sheet manufacturing method of the present invention can be applied. If one of the active material layers is not made from the electrode sheet of the present invention, an all-solid-state secondary battery can be manufactured by placing an appropriate material for forming the active material layer on a pressed body of the electrode sheet of the present invention and a solid electrolyte layer or solid electrolyte layer forming material, and applying appropriate pressure, or by stacking the electrode sheet of the present invention, a solid electrolyte layer or solid electrolyte layer forming material, and an appropriate material, and applying appropriate pressure. In this case, the pressurization method can be a method of pressing the active material layer precursor layer, and the applied pressure is not particularly limited, but can be, for example, 5 to 1500 MPa.

[0206] <Manufacturing method for all-solid-state secondary batteries using electrode sheets> A method for manufacturing an all-solid-state secondary battery using electrode sheets involves stacking an electrode sheet and a solid electrolyte layer, or stacking an electrode sheet and a solid electrolyte layer forming material, and then pressing them together to form an active material layer or an electrode (a laminate of a current collector and an active material layer). Here, when forming one of the active material layers with an electrode sheet, the electrode sheet and the solid electrolyte layer or solid electrolyte layer forming material are stacked. On the other hand, when forming both active material layers with an electrode sheet, the electrode sheet, the solid electrolyte layer or solid electrolyte layer forming material, and the electrode sheet are stacked, and the solid electrolyte layer or solid electrolyte layer forming material is placed between the two active material layers of the electrode sheet. In the manufacturing method using electrode sheets, when pressing, the pressing method can be a method of pressing the active material layer precursor layer, and the applied pressure is not particularly limited, but can be, for example, 5 to 1500 MPa. If one of the active material layers is not made from an electrode sheet, an all-solid-state secondary battery can be manufactured by placing a suitable material for forming the active material layer on top of a solid electrolyte layer or solid electrolyte layer forming material superimposed on an electrode sheet, and applying appropriate pressure. In this case, a method of pressing the active material layer precursor layer can be applied, and the applied pressure is not particularly limited, but can be, for example, 5 to 1500 MPa.

[0207] The atmosphere in which the battery manufacturing method is carried out is not particularly limited and can be the same as the atmosphere used for manufacturing electrode sheets.

[0208] In the battery manufacturing method and the method for manufacturing an all-solid-state secondary battery using an electrode sheet described above, the negative electrode active material layer can also be formed by depositing metal ions as metals onto the negative electrode current collector or the like during initialization or charging during use, without forming the negative electrode active material layer during the manufacturing of the all-solid-state secondary battery.

[0209] (initialization) It is preferable to initialize the all-solid-state secondary battery manufactured as described above after manufacturing or before use. Initialization is not particularly limited and can be performed, for example, by performing the initial charge and discharge under increased press pressure, and then releasing the pressure until it reaches the general operating pressure of the all-solid-state secondary battery.

[0210] The battery manufacturing method and the method for manufacturing an all-solid-state secondary battery using the electrode sheet described above make it possible to manufacture an all-solid-state secondary battery in which the increase in interfacial resistance is also suppressed. [Examples]

[0211] The present invention will be described in more detail below based on examples, but the present invention is not to be construed as being limited thereto. In the following examples, "parts" and "%" representing composition are by mass unless otherwise specified. In the present invention, "room temperature" means 25°C.

[0212] 1. Polymer synthesis Polymers B1 to B5, shown in the chemical formulas below, were synthesized as follows.

[0213] [Synthesis Example B1: Synthesis of Polymer B1 and Preparation of Binder Solution B1] ToughTec (registered trademark) H1041: Hydrogenated styrene-based thermoplastic elastomer (trade name, SEBS, manufactured by Asahi Kasei Corporation) was dissolved in butyl butyrate to obtain a polymer binder solution B1 (concentration 20% by mass) consisting of polymer B1.

[0214] [Synthesis Example B2: Synthesis of Polymer B2 and Preparation of Binder Solution B2] In a 100 mL volumetric flask, 29.2 g of octadecyl acrylate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 1.6 g of methacrylic acid (2,3-dihydroxypropyl) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 0.3 g of polymerization initiator V-601 (trade name, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added and dissolved in 36 g of butyl butyrate to prepare a monomer solution. Next, 20 g of butyl butyrate was added to a 300 mL three-necked flask and stirred at 80°C, to which the monomer solution was added dropwise over 2 hours. After the dropwise addition was complete, the temperature was raised to 90°C and stirred for 2 hours to synthesize polymer B2 ((meth)acrylic polymer), and a polymer binder solution B2 (concentration 35% by mass) consisting of polymer B2 was obtained.

[0215] [Synthesis Example B3: Synthesis of Polymer B3 and Preparation of Binder Solution B3] 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 92 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 uniformly dissolved. 0.08 g of Neostan U-600 (trade name, manufactured by Nitto Chemical Co., Ltd.) was added to the resulting solution and stirred at 80°C for 12 hours to synthesize polymer B3 (polyurethane), obtaining a polymer binder solution B3 (concentration 35% by mass) consisting of polymer B3.

[0216] [Synthesis Example B4: Synthesis of Polymer B4 and Preparation of Binder Dispersion B4] 200 g of heptane was poured into a 1 L three-necked flask equipped with a reflux condenser and a gas inlet stopcock, and nitrogen gas was introduced at a flow rate of 200 mL / min for 10 minutes, after which the temperature was raised to 80°C. A solution prepared in a separate container (a mixture of 177 g of ethyl acrylate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 13 g of acrylic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 100 g of macromonomer AB-6 (trade name, manufactured by Toagosei Co., Ltd.) (solid content), and 2.0 g of polymerization initiator V-601 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)) was added dropwise over 2 hours, and the mixture was then stirred at 80°C for 2 hours. An additional 1.0 g of V-601 was 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 of polymer binder B4 (concentration 10% by mass, particle size 150 nm) consisting of polymer B4 ((meth)acrylic polymer) was obtained.

[0217] [Synthesis Example B5: Preparation of Binder Dispersion B5] Polyvinylidene fluoride (manufactured by Aldrich) was dispersed in butyl butyrate to obtain polymer binder dispersion B5 (concentration 20% by mass, particle size 5 μm) consisting of polymer B5.

[0218] The synthesized polymers are shown below. The numbers in the lower right corner of each component indicate the content (mol%). The mass-average molecular weights of polymers B1 to B5, which form polymer binders B1 to B5, were measured using the method described above. The results were 100,000, 150,000, 50,000, 100,000, and 530,000 for polymers B1 to B5, respectively. Furthermore, the morphology (solubility or insolubility) of polymer binders B1 to B5 in the electrode composition, as described later, was determined by measuring their solubility in the dispersion medium (butyl butyrate) used in the electrode composition using the method described above. As a result, polymer binders B1 to B3 dissolved in the dispersion medium in the electrode composition, while polymer binders B4 and B5 dispersed as particles in the dispersion medium in the electrode composition.

[0219] [ka]

[0220] 2. Synthesis of sulfide-based inorganic solid electrolytes [Synthesis example A] 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. Specifically, 2.42 g of lithium sulfide (Li2S, Aldrich, purity >99.98%) and 3.90 g of phosphorus pentasulfide (P2S5, Aldrich, purity >99%) were weighed out in a glove box under an argon atmosphere (dew point -70°C), placed in an agate mortar, and mixed for 5 minutes using an agate pestle. The mixing ratio of Li2S to P2S5 was 75:25 molar ratio. Next, 66 g of 5 mm diameter zirconia beads were placed in a 45 mL zirconia container (manufactured by Fritsch), and the entire amount of the lithium sulfide and phosphorus pentasulfide mixture was added. 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), and mechanical milling (atomization) was performed at a temperature of 25 °C and a rotation speed of 510 rpm for 20 hours to obtain 6.20 g of yellow powder sulfide-based inorganic solid electrolyte (Li / P / S glass, hereinafter sometimes referred to as LPS). The particle size (volume average particle size) of this LPS was 8 μm.

[0221] [Particle size adjustment] The obtained LPS was wet-dispersed under the following conditions to adjust the particle size of the LPS. (Particle size adjustment example A1) 160 zirconia beads with a diameter of 5 mm were placed in a 45 mL zirconia container (manufactured by Fritsch), and 4.0 g of synthesized LPS and 6.0 g of diisopropyl ketone as an organic solvent were added. The container was then placed in a planetary ball mill P-7 and wet dispersion was performed at 250 rpm for 30 minutes to obtain LPS1 with a particle size (volume average particle size) of 2.5 μm. (Particle size adjustment examples A2 and A3) In the above particle size preparation example A1, LPS2 with a particle size of 1.0 μm and LPS3 with a particle size of 3.0 μm were obtained in the same manner as in particle size preparation example A1, except that the rotation speed of the wet dispersion was changed to 300 rpm or 200 rpm.

[0222] [Example 1] <Preparation of positive electrode composition (slurry) S-1> A positive electrode composition S-1 with a solid content of 65% by mass was prepared by mixing 70 parts by mass of NMC (lithium nickel manganese cobalt oxide, particle size 5 μm, manufactured by Aldrich) as the positive electrode active material, 27 parts by mass of LPS1 (particle size 2.5 μm) obtained in the above particle size preparation example A1 as the inorganic solid electrolyte, 2 parts by mass of acetylene black (particle size 0.1 μm, manufactured by Denka) as the conductive additive, 1 part by mass (in terms of solid content) of polymer binder solution B1 as the polymer binder, and a dispersion medium in the order of steps 1 and 2 below.

[0223] (Process 1) 20 g of 3 mm diameter zirconia beads were added to a 45 mL zirconia container (manufactured by Fritsch). Then, 27 parts by mass of inorganic solid electrolyte, 1 part by mass (in terms of solid content) of polymer binder solution B1, and butyl butyrate as a dispersion medium were added to adjust the solid content concentration to 60% by mass. Subsequently, this container was placed in a planetary ball mill P-7 (trade name, manufactured by Fritsch) and stirred for 30 minutes at a temperature of 25°C and a rotation speed of 100 rpm to obtain solid electrolyte composition S1-1 with a solid content concentration of 60% by mass. (Process 2) To the entire amount of solid electrolyte composition S1-1 in the container obtained in step (1), 70 parts by mass of positive electrode active material, 2 parts by mass of acetylene black, and butyl butyrate as a dispersion medium were added to adjust the solid content concentration to that shown in Table 1. Then, this container was set in a planetary ball mill P-7 and stirred for 30 minutes at a temperature of 25°C and a rotation speed of 100 rpm to obtain positive electrode composition S-1.

[0224] <Preparation of positive electrode compositions (slurries) S-2 to S-12 and cS-1 to cS-9> In the preparation of positive electrode composition S-1, the types (particle sizes) of the inorganic solid electrolyte and the types or content of the polymer binder were changed as shown in Table 1. The content of the solid electrolyte was changed so that the total mass of the inorganic solid electrolyte, positive electrode active material, polymer binder, and acetylene black was 100 parts by mass. Furthermore, the content of the dispersion medium used in step (2) was changed to set the solid content concentration of the positive electrode composition as shown in Table 1. Other than these changes, positive electrode compositions S-2 to S-12 and cS-1 to cS-9 were prepared in the same manner as the preparation of positive electrode composition S-1.

[0225] <Preparation of positive electrode sheet> Each of the positive electrode compositions S-1 to S-12 and cS-1 to cS-9 obtained above was applied onto a 20 μm thick aluminum foil using a Baker-type applicator (product name: SA-201, manufactured by Tester Sangyo Co., Ltd.), and then heated and dried (dispersed the dispersion medium) under the "coating and drying conditions" shown in Table 1. In this way, a positive electrode active material precursor layer was formed on the aluminum foil, and positive electrode sheets S-1 to S-12 and cS-1 to cS-9 for all-solid-state secondary batteries were prepared, respectively. Note that the positive electrode sheet S-12 is the same as the positive electrode sheet S-3.

[0226] In Table 1, the units for particle size (μm), solid content concentration (mass%), drying temperature (°C), drying time (hours), and packing efficiency (%) of inorganic solid electrolytics are omitted. Furthermore, the polymer binder content is shown as the content (mass%) relative to 100% mass of solid content of each cathode composition, but the units are omitted in the table.

[0227] [Table 1]

[0228] <Manufacturing of all-solid-state rechargeable batteries> Each of the fabricated positive electrode sheets S-1 to S-12 and cS-1 to cS-9 was punched out into a 10 mm diameter disc shape and placed in a polyethylene terephthalate (PET) cylinder with an inner diameter of 10 mm. 30 mg of LPS1 (particle size 2.5 μm) obtained in particle size adjustment example A1 was placed on the positive electrode active material precursor layer side of each cylinder, and 10 mm diameter stainless steel rods (SUS rods) were inserted through the openings at 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, pressurizing the positive electrode active material precursor layer and the LPS together. In this way (by the electrode sheet manufacturing method of the present invention), a positive electrode sheet having a positive electrode active material layer and a solid electrolyte layer in that order was manufactured on an aluminum foil substrate. For positive electrode sheet S-12, the pressure was set to 150 MPa and pressurized together with the LPS. Next, the SUS rod on the LPS side was temporarily removed, and a 9mm diameter disc-shaped In sheet (20μm thick) and a 9mm diameter disc-shaped Li sheet (20μm thick) were inserted in that order onto the LPS inside the cylinder. The removed SUS rod was reinserted into the cylinder and fixed in place under a pressure of 50MPa. In this way, all-solid-state secondary batteries (positive electrode half-cells) No. 101~112 and c101~c109, having the configuration of aluminum foil (20μm thick) - positive electrode active material layer (thickness shown in the "Film Thickness" column of Table 2) - solid electrolyte layer (250μm thick) - negative electrode active material layer (In / Li sheet, 30μm thick), were manufactured.

[0229] <Evaluation of positive electrode sheets> For each prepared positive electrode sheet, the film density, packing density, and film thickness of the positive electrode active material precursor layer were measured or calculated. The results are shown in the "Positive Electrode Sheet" column of Table 2. Note that in Table 2, film density (g / cm³) 3 The units for ), filling rate (%), and film thickness (μm) are omitted. (Calculation of membrane density) Each positive electrode sheet has a diameter of 10 mm (surface area: 0.785 cm²). 2The material was punched out and its mass was measured at 25°C. The mass of the positive electrode active material precursor layer (electrode composite) was calculated by subtracting the mass of the aluminum foil from the measured mass. Next, the thickness of the positive electrode active material precursor layer was measured at 25°C using a constant-pressure thickness gauge (Mitutoyo Corporation). 2 ) and the volume of the positive electrode active material precursor layer (cm³) 3 The mass (g) of the positive electrode active material precursor layer was calculated as the volume (cm³). 3 ) divided by the membrane density (g / cm³) 3 ) was calculated.

[0230] (Calculation of true density) The true density of the cathode active material precursor layer was calculated as described above. Specifically, the true density of each of the active material, inorganic solid electrolyte, conductive additive, and polymer binders B1-B5 was measured at 25°C using a density measuring device: BELPYCNO (product name, manufactured by Microtrac-Bel) by the gas displacement method. As a result, the true density (g / cm³) was determined. 3 The active material was 5.3, LPS1 was 2.0, LPS2 was 2.0, LPS3 was 2.0, the conductive additive was 2.0, polymer binders B1-4 were all 1.1, and polymer binder B5 was 1.8. Next, the true density of the positive electrode active material layer precursor (g / cm³) is calculated from the true densities of the active material, inorganic solid electrolyte, conductive additive, and polymer binder B1-B5, and their content ratios in the positive electrode composition, using the following formula. 3 ) was calculated. True density of the cathode active material precursor layer (g / cm³) 3 ) = [True density of active material × content ratio] + [True density of inorganic solid electrolyte × content ratio] + [True density of conductive additive × content ratio] + [(True density of polymer binder × content ratio)]

[0231] (Calculation of filling rate) The packing density (%) of the positive electrode active material precursor layer was calculated using the method described above. (Measurement of film thickness) The thickness of the positive electrode active material precursor layer was defined as the thickness (μm) measured in the above calculation of the film density.

[0232] (Measurement of particle size of inorganic solid electrolytes) Inorganic solid electrolytic material was recovered from the active material precursor layer of each positive electrode sheet, and its particle size was measured using the above measurement method. The results showed that the particle size was in close agreement with that of the inorganic solid electrolytic material used in the preparation of the electrode composition.

[0233] The following evaluations were performed on each electrode sheet and each all-solid-state secondary battery manufactured, and the results are shown in the "All-Solid-State Secondary Battery" column of Table 2. Note that all-solid-state secondary batteries that did not pass the bending resistance test were not evaluated further (except for the all-solid-state secondary battery cS-8). Furthermore, in Table 2, the filling rate (%) and film density (g / cm³) are shown. 3 The units in each of the following terms are omitted.

[0234] <Evaluation 1-1: Calculation of the packing density of the positive electrode active material layer> Each all-solid-state secondary battery was cut open, and its cross-section was observed using a scanning electron microscope (SEM) to measure the thickness (average thickness) of the positive electrode active material layer. Using the obtained thickness, the packing density was calculated in the same manner as the packing density of the positive electrode active material precursor layer described above. <Evaluation 1-2: Calculation of film density of the positive electrode active material layer> The film density of the positive electrode active material layer extracted from each all-solid-state secondary battery was measured in the same manner as the film density of the positive electrode active material layer precursor layer described above. The packing density and film density of the positive electrode active material layer in each positive electrode sheet are the same as those of the positive electrode active material layer in the all-solid-state secondary battery shown in Table 2.

[0235] <Evaluation 2: Bending resistance test of electrode sheets> To assess the transportability of the electrode sheets, we evaluated the adhesion of solid particles in the positive electrode active material precursor layer of each manufactured electrode sheet, as well as the bonding between the positive electrode active material precursor layer and the aluminum foil (current collector). The results are shown in the "Bending Resistance" column of the "All-Solid-State Secondary Battery" section in Table 2. Each electrode sheet was cut into a rectangle measuring 3 cm wide x 14 cm long. Using a cylindrical mandrel testing machine (product code 056, Allgood), one end of the cut sheet specimen was fixed to the machine in the longitudinal direction, and the cylindrical mandrel was positioned so that it made contact with the center of the sheet specimen. The other end of the sheet specimen in the longitudinal direction was pulled along its length with a force of 2 N, and bent 180° along the circumference of the mandrel (with the mandrel as the axis). The sheet specimen was set with the positive electrode active material precursor layer on the opposite side from the mandrel (the base material or current collector on the mandrel side), and the width parallel to the axis of the mandrel. The test was performed by gradually decreasing the diameter of the mandrel from 32 mm. The evaluation was performed by measuring the minimum diameter at which no defects (cracks, fractures, chips, etc.) due to the collapse of solid particles were observed in the positive electrode active material precursor layer, both when the material was wound around a mandrel and when it was unwound and restored to a sheet form, and where no separation between the positive electrode active material precursor layer and the current collector was observed. The evaluation was then conducted based on which of the following evaluation criteria this minimum diameter corresponded to. In this test, a smaller minimum diameter means that the solid particles constituting the positive electrode active material precursor layer maintain their adhesion while remaining highly flexible. This allows the particle to follow bending stresses even when subjected to roll conveying processes in industrial manufacturing methods, suppressing the collapse of the solid particles' adhesion. The passing level for this test is evaluation criterion "B" or higher. The minimum diameter of all solid-state secondary batteries No. c101, c102, c105, c106, c108, and c109 was 32 mm. - Evaluation Criteria - A: Minimum diameter <14mm B: 14mm≦Minimum diameter<25mm C: 25mm≦Minimum diameter

[0236] <Evaluation 3: Resistance Test> The battery resistance of each manufactured all-solid-state secondary battery was evaluated using the method described below. The results are shown in the "Battery Resistance" column under the "All-Solid-State Secondary Battery" column in Table 2. Specifically, each manufactured solid-state rechargeable battery (half-cell) was charged at 25°C with a charging current of 0.1mA until the battery voltage reached 3.6V. Then, each solid-state rechargeable battery was initialized by discharging it with a discharge current of 0.1mA until the battery voltage reached 1.9V. Subsequently, as a rate test, the battery was charged at a charging current of 0.1 mA in a 25°C environment until the battery voltage reached 3.6 V, and then discharged at a discharge current of 0.1 mA until the battery voltage reached 1.9 V (Charge / Discharge Process (1)). After that, the battery was charged again at a charging current of 0.1 mA until the battery voltage reached 3.6 V, and then discharged at a discharge current of 1.5 mA until the battery voltage reached 1.9 V (Charge / Discharge Process (2)). After the charge-discharge processes (1) and (2) were completed, the discharge capacity was measured using the TOSCAT-3000 charge-discharge evaluation device (product name, manufactured by Toyo System Co., Ltd.). Using the measured discharge capacity, the discharge capacity retention rate (%) was calculated from the following formula, and the rate characteristics of the all-solid-state secondary battery were evaluated by applying it to the evaluation criteria below. In this test, a higher retention rate (%) indicates lower battery resistance (resistance of the positive electrode active material layer) of the all-solid-state secondary battery, and a score of "B" or higher is considered a passing level for this test. The maintenance percentages (%) for all-solid-state secondary batteries No. c103, c104, and c107 were 65%, 65%, and 68%, respectively, while the maintenance percentages (%) for all-solid-state secondary batteries No. c108 and c109 were 62% and 64%, respectively. Maintenance rate (%) = [Discharge capacity of charge / discharge process (2) / Discharge capacity of charge / discharge process (1)] × 100 - Evaluation Criteria - A:90%≦Retention rate B:80%≦Retention rate<90% C: Retention rate <80%

[0237] [Table 2]

[0238] The results shown in Tables 1 and 2 indicate the following: Comparative example positive electrode sheets that do not meet the polymer binder content or filling ratio requirements exhibit poor transportability or fail to suppress the resistance increase of the all-solid-state secondary battery. In contrast, the electrode sheets of the embodiment that satisfy the polymer binder content and filling rate exhibit excellent transportability, and a highly filled active material layer can be formed by pressing during the manufacturing process of the all-solid-state secondary battery, thereby effectively suppressing the increase in resistance of the all-solid-state secondary battery.

[0239] Although we have described the present invention along with its embodiments, we do not intend to limit our invention in any detail of the description unless specifically designated, and we believe that it should be interpreted broadly without contradicting the spirit and scope of the invention as set forth in the appended claims.

[0240] This application claims priority based on Japanese Patent Application No. 2021-159110, filed in Japan on 29 September 2021, the contents of which are incorporated herein by reference as part of this specification. [Explanation of symbols]

[0241] 1 Negative electrode current collector 2 Negative electrode active material layer 3 Solid electrolyte layer 4 Cathode active material layer 5 Positive electrode current collector 6. Operating parts 8 Base material 9 Active material layer precursor layer 10 All-solid-state secondary battery 11 Electrode Sheet

Claims

1. An electrode sheet comprising an active material precursor layer containing an inorganic solid electrolyte having conductivity of metal ions belonging to Group 1 or Group 2 of the periodic table, an active material, and a polymer binder, An electrode sheet wherein the active material precursor layer contains the polymer binder in an amount of 0.5% to 3% by mass, exhibits a packing density of 35 to 50%, and has a layer thickness of 150 μm or more.

2. The electrode sheet according to claim 1, wherein the inorganic solid electrolyte is a sulfide-based inorganic solid electrolyte.

3. The electrode sheet according to claim 1, wherein the active material layer precursor layer is a positive electrode active material layer precursor layer having a film density of 1.4 to 2.0 g / cm³.

4. The electrode sheet according to claim 1, wherein the active material layer precursor layer is a negative electrode active material layer precursor layer having a film density of 0.8 to 1.0 g / cm³.

5. A method for producing an electrode sheet according to any one of claims 1 to 4, comprising coating an electrode composition containing an inorganic solid electrolyte having conductivity of metal ions belonging to Group 1 or Group 2 of the periodic table, an active material, a polymer binder, and a dispersion medium onto a substrate and drying to form an active material layer precursor layer, A step of preparing the electrode composition by setting the solid content of the polymer binder to 0.5% by mass or more and 3% by mass or less, A method for manufacturing an electrode sheet, comprising the step of setting the packing ratio of the active material precursor layer to 35 to 50%.

6. A method for manufacturing an electrode sheet having an active material layer on a substrate, A method for manufacturing an electrode sheet, comprising pressing the active material layer precursor layer of an electrode sheet obtained by the method for manufacturing an electrode sheet according to claim 5 to form an active material layer.

7. A method for manufacturing an all-solid-state secondary battery comprising a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order, A method for manufacturing an all-solid-state secondary battery, wherein at least one of the positive electrode active material layer and the negative electrode active material layer is formed by pressing together an electrode sheet obtained by the method for manufacturing an electrode sheet according to claim 5 with a solid electrolyte layer or a solid electrolyte layer forming material.

8. An all-solid-state secondary battery manufactured by the method for manufacturing an all-solid-state secondary battery described in Claim 7.

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