WO2020059550A1

WO2020059550A1 - Production method for all-solid secondary battery layered member, and production method for all-solid secondary battery

Info

Publication number: WO2020059550A1
Application number: PCT/JP2019/035316
Authority: WO
Inventors: 昭人福永
Original assignee: 富士フイルム株式会社
Priority date: 2018-09-18
Filing date: 2019-09-09
Publication date: 2020-03-26
Also published as: JP7064613B2; JPWO2020059550A1

Abstract

A production method for an all-solid secondary battery layered member that includes: a layered body that has, in order, a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer; and collector layers that are arranged on the surfaces of the positive electrode active material layer and the negative electrode active material layer of the layered body. The production method includes using wet-on-wet coating to form a layered structure of: at least one active material layer from among the abovementioned positive electrode active material layer and the abovementioned negative electrode active material layer; and a collector layer that contacts the active material layer. A production method for an all-solid secondary battery, the production method using the production method for an all-solid secondary battery layered member.

Description

Method for manufacturing laminated member for all-solid-state secondary battery and method for manufacturing all-solid-state secondary battery

The present invention relates to a method for manufacturing a laminated member for an all-solid secondary battery and a method for manufacturing an all-solid secondary battery.

A lithium ion secondary battery is a storage battery having a negative electrode, a positive electrode, and an electrolyte sandwiched between the negative electrode and the positive electrode, and capable of charging and discharging by reciprocating lithium ions between the two electrodes. Conventionally, organic electrolytes have been used as electrolytes in lithium ion secondary batteries. However, the organic electrolyte is liable to leak, and a short circuit may occur in the battery due to overcharging or overdischarging, causing ignition, and further improvement in safety and reliability is required.
Under such circumstances, an all-solid secondary battery using an inorganic solid electrolyte instead of an organic electrolyte has been receiving attention. The all-solid-state secondary battery has a negative electrode, an electrolyte, and a positive electrode, all of which are solid, greatly improving the safety and reliability of batteries using organic electrolytes, and extending the life of the battery. It is said to be. Further, the all-solid-state secondary battery can have a laminated structure in which electrodes and electrolytes are directly arranged and arranged in series. Therefore, higher energy density can be achieved as compared with a secondary battery using an organic electrolyte, and application to various electronic devices, electric vehicles, large storage batteries, and the like is expected.

The basic layer configuration of an all solid state secondary battery is a laminated structure including a positive electrode layer, a solid electrolyte layer, and a negative electrode layer. The positive electrode of an all solid state secondary battery generally has a configuration in which a positive electrode current collector layer made of a metal foil and a positive electrode active material layer are laminated, and the positive electrode active material layer is in contact with the solid electrolyte layer. Similarly, the negative electrode also generally has a configuration in which a negative electrode current collector layer made of a metal foil and a negative electrode active material layer are laminated, and has a configuration in which the negative electrode active material layer is in contact with the solid electrolyte layer. In the positive electrode and the negative electrode having such a configuration, there is a limitation in improving the adhesion between the metal foil serving as the current collector layer and the active material layer formed of solid particles, and the current collector layer and the active material layer Between the current collector layer and the active material layer may be insufficient.
As a technique for addressing this problem, Patent Document 1 discloses that all functional layers of a first current collector layer, a first active material layer, an electrolyte layer, a second active material layer, and a second current collector layer are applied. Is described. According to the technique described in Patent Document 1, it is said that the adhesion between the current collector layer and the active material layer can be increased, and a battery having good characteristics can be manufactured.

The all-solid-state secondary battery includes a stacked body in which a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer are stacked in this order, and a collector disposed in contact with the positive electrode active material layer or the negative electrode active material layer of the stacked body. There is known a configuration of a plurality of units in which a stacked structure composed of a current collector layer and one unit are stacked on a current collector such as a metal foil so that the current collector layers do not contact each other. ing. With such a plurality of units, the output of the battery can be increased. A monopolar type and a bipolar type are known as a multiple unit configuration. In the monopolar type, a positive electrode active material layer is provided on both sides of a positive electrode current collector layer, and a negative electrode current collector is provided on both sides of a negative electrode current collector layer. That is, the active material layers disposed on both sides of the current collector layer are of the same type. On the other hand, the bipolar type has a structure in which a positive electrode active material layer and a negative electrode active material layer are arranged on both sides of one current collector layer.

JP 2012-64487 A

者 The present inventors have repeatedly studied the technology described in Patent Document 1 for the purpose of further improving battery performance. As a result, as described in Patent Literature 1, a coating solution (slurry) containing the constituent material of the current collector layer was prepared, and this coating solution was applied on the active material layer to form a current collector layer. Even in such a case, the adhesion between the current collector layer and the active material layer is reduced by the low resistance required during charge / discharge (improved electron conductivity between the current collector layer and the active material layer during charge / discharge) required in recent years. It has not been possible to raise the level to a sufficiently satisfactory level, and it has been found that there is a limitation in improving the battery performance.

The present invention provides a method for manufacturing a laminated member for an all-solid secondary battery, which can be used as a constituent member of the all-solid secondary battery to obtain an all-solid secondary battery with sufficiently suppressed resistance during charge and discharge. The task is to Another object of the present invention is to provide a method for manufacturing an all-solid-state secondary battery capable of obtaining an all-solid-state secondary battery with sufficiently reduced resistance during charge and discharge.

The present inventors have conducted intensive studies in view of the above problems. As a result, a laminate having a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order, and a current collector layer disposed on each surface of the positive electrode active material layer and the negative electrode active material layer of the laminate, In the production of a laminated member for an all-solid secondary battery including, a positive electrode active material layer or a negative electrode active material layer, the formation of a laminated structure of a current collector layer in contact with it, by wet-on-wet coating, the obtained solid By applying the laminated member for a secondary battery to an all-solid secondary battery, it has been found that an all-solid secondary battery with sufficiently suppressed resistance can be provided. The present invention has been further studied based on this finding, and has been completed.

That is, the above problem was solved by the following means.
[1]
A laminate including a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order, and a current collector layer disposed on each surface of the positive electrode active material layer and the negative electrode active material layer of the laminate. In the production of laminated members for solid state rechargeable batteries,
An all-solid-state method including forming a laminated structure of at least one active material layer of the positive electrode active material layer and the negative electrode active material layer and a current collector layer in contact with the active material layer by wet-on-wet coating; Method for producing laminated member for secondary battery.
[2]
The laminated member for an all-solid secondary battery includes a first current collector layer made of a metal foil, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a second current collector layer. The structure in which the positive electrode active material layer, the solid electrolyte layer, the negative electrode active material layer, and the second current collector layer are formed in a laminated structure in this order is a first structure made of the above metal foil. The method for producing a laminated member for an all-solid-state secondary battery according to [1], wherein the method is performed by simultaneous multi-layer coating on a current collector layer.
[3]
The above-described laminated member for an all-solid secondary battery includes a first current collector layer made of a metal foil, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, and a second current collector layer. The structure in which the negative electrode active material layer, the solid electrolyte layer, the positive electrode active material layer, and the second current collector layer are formed in a stacked structure in this order is formed by the first metal foil. The method for producing a laminated member for an all-solid-state secondary battery according to [1], wherein the method is performed by simultaneous multi-layer coating on a current collector layer.
[4]
The laminated member for an all-solid secondary battery has a laminated body in which a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer are laminated in this order, and is in contact with the positive electrode active material layer or the negative electrode active material layer of the laminated body. A stacked unit composed of a current collector layer arranged and arranged on a current collector layer made of metal foil, has a stacked structure in which a plurality of layers are stacked so that the current collector layers do not contact each other,
The production of a laminated member for an all-solid-state secondary battery according to [1], wherein the lamination structure in which the lamination units are stacked in a plurality of stages is formed by simultaneous multi-layer coating on the current collector layer made of the metal foil. Method.
[5]
The method for producing a laminated member for an all-solid secondary battery according to any one of [1] to [4], wherein the current collector layer formed by wet-on-wet coating contains a particulate binder.
[6]
The method for producing a laminated member for an all-solid secondary battery according to any one of [1] to [5], wherein the solid electrolyte constituting the solid electrolyte layer is a sulfide-based inorganic solid electrolyte.
[7]
A laminated member for an all-solid secondary battery is obtained by the method for producing a laminated member for an all-solid secondary battery according to any one of [1] to [6], and the laminated member for an all-solid secondary battery is entirely used A method for producing an all-solid secondary battery, which obtains a solid secondary battery.

において In the description of the present invention, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit and an upper limit.

According to the method for manufacturing a laminated member for an all-solid-state secondary battery of the present invention, by using it as a constituent member of the all-solid-state secondary battery, it is possible to obtain an all-solid-state secondary battery with sufficiently suppressed resistance during charge and discharge. It is possible to provide a laminated member for an all-solid secondary battery that can be obtained. Further, according to the method for manufacturing an all-solid secondary battery of the present invention, it is possible to provide an all-solid secondary battery in which resistance during charging and discharging is sufficiently suppressed.

FIG. 1 is a longitudinal sectional view schematically showing a layer configuration in a monopolar type all solid state secondary battery. FIG. 2 is a longitudinal sectional view schematically illustrating a layer configuration in a bipolar type all-solid secondary battery. FIG. 3 is a longitudinal sectional view schematically illustrating a basic configuration of the all solid state secondary battery.

The preferred embodiment of the method for producing a laminated member for an all-solid secondary battery and the method for producing an all-solid secondary battery of the present invention will be described. It is not limited.

[Method of Manufacturing Laminated Member for All-Solid Secondary Battery]
The method for producing a laminated member for an all-solid secondary battery of the present invention (hereinafter, also referred to as “the production method of the present invention”) is a laminate having a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order. And a laminated member for an all-solid-state secondary battery including a current collector layer disposed on each surface of the positive electrode active material layer and the negative electrode active material layer of the laminate (hereinafter, also referred to as a “laminated member of the present invention”). ).
In the production method of the present invention, the formation of a laminated structure of at least one active material layer of the positive electrode active material layer and the negative electrode active material layer and a current collector layer in contact with the active material layer is performed by wet-on-wet coating. Including doing.
In the present invention, “wet-on-wet coating” refers to a coating method in which a plurality of coating films are repeatedly applied without drying (that is, in a wet state). More specifically, it means that another coating film is formed on this coating film in a state where the residual solvent amount of the formed coating film is 5% by mass or more. For example, in a coating method by sequential coating, even if the formed coating film is dried to a certain extent, when a residual coating film amount of the coating film is 5% by mass or more and another coating film is formed thereon, the “wet” On-wet application ". Simultaneous multi-layer coating, in which a plurality of coating solutions (slurries) for forming different layers are simultaneously supplied to a coating device from the stage of a coating process, and a plurality of stacked coating solutions are simultaneously coated on a substrate, is also referred to as “multi-layer coating”. Wet-on-wet coating ".

好ましい Preferred laminated structures that the laminated member of the present invention can employ include the following laminated structures (a) to (c).

(A) A laminated structure having a first current collector layer / positive electrode active material layer / solid electrolyte layer / negative electrode active material layer / second current collector layer made of metal foil in this order.
(B) A laminated structure having a first current collector layer / a negative electrode active material layer / a solid electrolyte layer / a positive electrode active material layer / a second current collector layer composed of a metal foil in this order.
(C) A laminate in which a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer are laminated in this order, and a current collector layer disposed in contact with the positive electrode active material layer or the negative electrode active material layer of the laminate. And a stacked structure in which a plurality of stacked units are stacked on a current collector layer made of metal foil so that the current collector layers do not contact each other.

において In (a) above, the first current collector layer made of a metal foil becomes a base material when forming a coating film. For example, when forming the positive electrode active material layer / solid electrolyte layer / negative electrode active material layer / second current collector layer by simultaneous multilayer coating, simultaneous multilayer coating is performed on the first current collector layer made of metal foil. Will be This is the same for (b). The laminated structure of (a) and (b) corresponds to the layer configuration of the all-solid-state secondary battery shown in FIG. 3 described later.

In the above (c), in one laminate unit, the current collector layer constituting the laminate unit is a positive electrode active material of a laminate in which a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer are laminated in this order. It is disposed in contact with one of the layer and the negative electrode active material layer. On the surface of the active material layer having no current collector layer, a current collector layer of another laminated unit in contact with the surface is provided.
That is, the stacking of a plurality of stacked units is such that the current collectors of the stacked units are not in contact with each other, and the active material layer of another stacked unit is arranged on the current collector layer surface of a certain stacked unit. I do.
As a stacked configuration in which a plurality of stacked units are stacked, there are a monopolar type stacked configuration and a bipolar type stacked configuration. In the monopolar type lamination structure, in the form in which the lamination units are stacked, the same type of active material layer is arranged on both surfaces of the current collector layer constituting the lamination unit. That is, when the positive electrode active material layer is provided on one surface of one current collector layer, the positive electrode active material layer is also provided on the other surface. Similarly, when the negative electrode active material layer is provided on one surface of one current collector layer, the negative electrode active material layer is also provided on the other surface.
FIG. 1 shows an example of a monopolar stacked structure. This monopolar lamination structure (lamination member 101) is composed of two types of lamination units. That is, a unit in which a current collector layer 5 is provided in contact with the positive electrode active material layer 2 of a laminate in which the positive electrode active material layer 2, the solid electrolyte layer 3, and the negative electrode active material layer 4 are laminated in this order (FIG. B), and a current collector layer 5 was provided in contact with the negative electrode active material layer 4 of a laminate in which the positive electrode active material layer 2, the solid electrolyte layer 3, and the negative electrode active material layer 4 were laminated in this order. The unit (A in FIG. 1) has a structure in which a plurality of layers are stacked on the current collector layer (metal foil) 1 so that the current collector layers do not contact each other (FIG. 1 shows a structure in which three layers are stacked). Thereby, a monopolar type laminated structure can be obtained.
On the other hand, in the bipolar type lamination structure, in a form in which the lamination units are stacked, different types of active material layers are arranged on both surfaces of the current collector layer constituting the lamination unit. That is, when the positive electrode active material layer is provided on one surface of one current collector layer, the negative electrode active material layer is provided on the other surface.
FIG. 2 shows an example of a bipolar type lamination structure. This bipolar type lamination structure (lamination member 102) is composed of one type of lamination unit. That is, a unit in which a current collector layer 5 is provided in contact with the negative electrode active material layer 4 of a laminate in which the positive electrode active material layer 2, the solid electrolyte layer 3, and the negative electrode active material layer 4 are laminated in this order (FIG. A) in which a plurality of layers are stacked on the current collector layer (metal foil) 1 so that the current collector layers do not contact each other (FIG. 2 shows a structure in which three layers are stacked) is a bipolar type. Can be adopted. In addition, a unit in which a current collector layer is provided in contact with the positive electrode active material layer of a laminate in which a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer are stacked in this order, A bipolar stacked structure can also be obtained by stacking a plurality of layers on the current collector layer (metal foil) so as not to be in contact with each other.

において In the present invention, the expression “laminated unit” is used for convenience to specify the layer configuration of the laminated structure. That is, the term “laminated unit” or “laminated structure in which a plurality of stacked units are stacked” does not mean a form in which a plurality of laminated units are prepared in advance and the plurality of laminated units are actually stacked. A slurry for forming each of the positive electrode active material layer, the solid electrolyte layer, the negative electrode active material layer, and the current collector layer is repeatedly coated one by one on the current collector layer made of a metal foil, or the positive electrode active material layer , A solid electrolyte layer, a negative electrode active material layer, and a current collector layer are coated simultaneously so as to be repeated in order, and the finally completed overall laminated structure is a “laminated unit” If the same laminated structure as the whole is included in the laminated structure of (c) above.

In the production method of the present invention, when forming the laminated member having the laminated structure of (a), the formation of the laminated structure formed by the negative electrode active material layer and the current collector layer in contact with the negative electrode active material layer is performed by a wet process. This is performed by on-wet coating. For example, a slurry containing a constituent material of a negative electrode active material layer is applied and coated on a solid electrolyte of a three-layer structure of a first current collector layer / a positive electrode active material layer / a solid electrolyte layer made of a metal foil. A film is formed, and a slurry containing the constituent material of the second current collector layer is applied in a state where the residual solvent amount of the coating film is 5% by mass or more. After the application, the coating is dried to obtain a laminated member having the above-mentioned laminated structure (a). A slurry containing the constituent material of the negative electrode active material layer and a slurry containing the constituent material of the second current collector layer can be simultaneously applied on the solid electrolyte layer.
The slurry containing the constituent material of the solid electrolyte layer and the slurry of the negative electrode active material layer were formed on the positive electrode active material layer of the two-layer structure of the first current collector layer / positive electrode active material layer made of metal foil. The slurry containing the material and the slurry containing the constituent material of the second current collector layer may be sequentially or simultaneously multi-layer coated by wet-on-wet coating.
Further, a slurry containing a constituent material of a positive electrode active material layer, a slurry containing a constituent material of a solid electrolyte layer, and a slurry containing a constituent material of a negative electrode active material layer are formed on a first current collector layer made of a metal foil. And the slurry containing the constituent material of the second current collector layer may be sequentially or simultaneously multi-layer coated by wet-on-wet coating.
In consideration of mass production, a slurry containing a constituent material of the positive electrode active material layer, a slurry containing a constituent material of the solid electrolyte layer, and a structure of the negative electrode active material layer are formed on the first current collector layer made of a metal foil. It is preferable that the slurry containing the material and the slurry containing the constituent material of the second current collector layer be simultaneously and multi-layer coated.

In the production method of the present invention, when forming the laminated member having the laminated structure of (b), the formation of the laminated structure formed by the positive electrode active material layer and the current collector layer in contact with the positive electrode active material layer is performed by a wet process. This is performed by on-wet coating. For example, a slurry containing a constituent material of a positive electrode active material layer is applied and coated on a solid electrolyte of a three-layer structure of a first current collector layer / a negative electrode active material layer / a solid electrolyte layer made of a metal foil. A film is formed, and a slurry containing the constituent material of the second current collector layer is applied in a state where the residual solvent amount of the coating film is 5% by mass or more. After the application, it is dried to obtain a laminated member having the above-mentioned laminated structure (b). A slurry containing the constituent material of the positive electrode active material layer and a slurry containing the constituent material of the second current collector layer may be simultaneously applied on the solid electrolyte.
Also, a slurry containing a constituent material of a solid electrolyte layer and a slurry of a positive electrode active material layer are formed on a negative electrode active material layer of a two-layer structure of a first current collector layer / anode active material layer made of a metal foil. The slurry containing the material and the slurry containing the constituent material of the second current collector layer may be sequentially or simultaneously multi-layer coated by wet-on-wet coating.
Further, a slurry containing a constituent material of a negative electrode active material layer, a slurry containing a constituent material of a solid electrolyte layer, and a slurry containing a constituent material of a positive electrode active material layer are formed on a first current collector layer made of a metal foil. And the slurry containing the constituent material of the second current collector layer may be sequentially or simultaneously multi-layer coated by wet-on-wet coating.
In consideration of mass production, a slurry containing a constituent material of a negative electrode active material layer, a slurry containing a constituent material of a solid electrolyte layer, and a structure of a positive electrode active material layer are formed on a first current collector layer made of a metal foil. It is preferable that the slurry containing the material and the slurry containing the constituent material of the second current collector layer be simultaneously and multi-layer coated.

In the production method of the present invention, when forming the laminated member having the laminated structure of (c), at least one active material layer in the laminated structure in which the laminated units are stacked in a plurality of stages, and a collection member in contact with the active material layer. The formation of the laminated structure with the electric conductor layer is performed by wet-on-wet coating. More preferably, each layer constituting each laminated unit is formed by sequentially or simultaneously applying a slurry containing the constituent material of each layer onto a current collector layer made of a metal foil, and then drying and forming the laminated unit. Form a laminated structure having a configuration in which the layers are stacked in a plurality of stages.
In consideration of mass production, each layer constituting each laminated unit is formed by simultaneously applying a slurry containing the constituent material of each layer onto a current collector layer made of a metal foil, and then drying the laminated unit. It is preferable to form a laminated structure having a configuration in which a plurality of layers are stacked. In this case, the formation of the laminated structure can be performed in one step, and the production efficiency of a monopolar or bipolar laminated member can be greatly increased.

スラリー The slurry itself for forming each of the above layers can be prepared by a conventional method. Specifically, it can be prepared by mixing at least a constituent material of each layer described below and a dispersion medium. This mixing can be performed using various mixers. For example, a ball mill, a bead mill, a planetary mixer, a blade mixer, a roll mill, a kneader, a disk mill and the like can be mentioned. The content of the constituent material of each layer in the slurry is not particularly limited as long as a coating film exhibiting a desired function can be formed, and is appropriately set in consideration of the film thickness, dispersibility, and the like.

Examples of the dispersion medium used for the slurry include alcohol compound solvents, ether compound solvents, amide compound solvents, amino compound solvents, ketone compound solvents, ester compound solvents, aromatic compound solvents, aliphatic compound solvents, and nitrile compound solvents. .
Examples of the alcohol compound solvent include methyl alcohol, ethyl alcohol, 1-propyl alcohol, 2-butanol, ethylene glycol, propylene glycol, glycerin, 1,6-hexanediol, 1,3-butanediol, and 1,4- Butanediol.

Examples of the ether compound solvent include alkylene glycol alkyl ethers (ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol, dipropylene glycol, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol, polyethylene glycol, propylene glycol dimethyl ether, Propylene glycol monomethyl ether, tripropylene glycol monomethyl ether, diethylene glycol monobutyl ether, diethylene glycol dibutyl ether, etc., dialkyl ethers (dimethyl ether, diethyl ether, dibutyl ether, etc.), tetrahydrofuran, and dioxane (1,2-, 1,3- Including 1,4-isomers) of the like.

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

(4) Examples of the amino compound solvent include triethylamine and tributylamine.

(4) Examples of the ketone compound solvent include acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, dibutyl ketone, and diisobutyl ketone.

Examples of the ester compound solvent include methyl acetate, ethyl acetate, propyl acetate, butyl acetate, pentyl acetate, hexyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, and propyl butyrate. Butyl butyrate, isobutyl isobutyrate, pentyl butyrate, methyl valerate, ethyl valerate, propyl valerate, butyl valerate, methyl caproate, ethyl caproate, propyl caproate, and butyl caproate.

Examples of the aromatic compound solvent include benzene, toluene, xylene, and mesitylene.

Examples of the aliphatic compound solvent include hexane, heptane, cyclohexane, methylcyclohexane, ethylcyclohexane, decalin, octane, pentane, cyclopentane, and cyclooctane.

Examples of the penitrile compound solvent include acetonitrile, propylonitrile, and butyronitrile.

The method of applying each of the above slurries for film formation is not particularly limited and can be appropriately selected. For example, in the case of sequential multilayer coating, it can be performed by a usual coating method such as an extrusion die coater, an air doctor coater, a bread coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, and a bar coater.
Also, simultaneous multi-layer coating can be performed by a conventional method. For example, JP-A-2005-271283 and JP-A-2006-247967 can be referred to. Further, for example, simultaneous multi-layer coating can be performed using a die (multi-layer dedicated Gieser) described in JP-A-2018-122283.
Further, the drying temperature of the coating film after performing the wet-on-wet coating is not particularly limited, and is preferably 30 ° C. or higher, more preferably 60 ° C. or higher, and further preferably 80 ° C. or higher. Further, the drying temperature is preferably 300 ° C. or lower, more preferably 250 ° C. or lower, and further preferably 200 ° C. or lower.

Next, the constituent materials of each layer of the laminated member of the present invention will be described.

<Solid electrolyte layer>
The solid electrolyte layer that constitutes the laminated member of the present invention can be formed of a general constituent material used for a solid electrolyte layer in an all-solid secondary battery. In the present invention, the solid electrolyte layer preferably has an inorganic solid electrolyte having ion conductivity of a metal belonging to

Group

1 or 2 of the periodic table, and further contains a binder if necessary. The solid electrolyte layer constituting the all-solid secondary battery of the present invention can be formed, for example, by applying a solid electrolyte composition (slurry) containing the inorganic solid electrolyte, the binder, and the dispersion medium described above. it can. The content of each component of the solid electrolyte composition can be appropriately adjusted according to the purpose. For example, in the solid content of the solid electrolyte composition, the content of the inorganic solid electrolyte is preferably set to 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and further preferably 90% by mass or more. preferable.

(Inorganic solid electrolyte)
In the present invention, the inorganic solid electrolyte is an inorganic solid electrolyte, and the solid electrolyte is a solid electrolyte in which ions can move inside. Since it does not contain an organic substance as a main ion conductive material, it is an organic solid electrolyte (a polymer electrolyte represented by polyethylene oxide (PEO) and the like; an organic represented by lithium bis (trifluoromethanesulfonyl) imide (LiTFSI) and the like) Electrolyte salt). Further, since the inorganic solid electrolyte is a solid in a steady state, it is not usually dissociated or released into cations and anions. In this regard, it is also clearly distinguished from an inorganic electrolyte salt (LiPF ₆ , LiBF ₄ , LiFSI, LiCl, or the like) in which cations and anions are dissociated or released in the electrolyte solution or the polymer. The inorganic solid electrolyte is not particularly limited as long as it has ion conductivity of a metal belonging to

Group

1 or 2 of the periodic table, and generally has no electron conductivity.

In the present invention, the inorganic solid electrolyte has ion conductivity of a metal belonging to

Group

1 or 2 of the periodic table. As the inorganic solid electrolyte, a solid electrolyte material applied to this type of product can be appropriately selected and used. Representative examples of the inorganic solid electrolyte include (i) a sulfide-based inorganic solid electrolyte and (ii) an oxide-based inorganic solid electrolyte. In terms of high ionic conductivity and ease of interparticle interfacial bonding, sulfides are preferred. A system inorganic solid electrolyte is preferred.
When the all-solid secondary battery of the present invention is an all-solid lithium ion secondary battery, the inorganic solid electrolyte preferably has lithium ion ionic conductivity.

(I) Sulfide-based inorganic solid electrolyte The sulfide-based inorganic solid electrolyte contains a sulfur atom (S) and has ion conductivity of a metal belonging to

Group

1 or 2 of the periodic table, and And a compound having an electronic insulating property are preferable. The sulfide-based inorganic solid electrolyte preferably contains at least Li, S, and P as elements and has lithium ion conductivity, but depending on the purpose or case, other than Li, S, and P, It may contain an element.

Examples of the sulfide-based inorganic solid electrolyte include a lithium-ion conductive sulfide-based inorganic solid electrolyte satisfying the composition represented by the following formula (I).

_{_{_{_{L a1 M b1 P c1 S d1}}}} A e1 formula (I)

In the formula, L represents an element selected from Li, Na and K, and Li is preferable. 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 indicate the composition ratio of each element, and a1: b1: c1: d1: e1 satisfies 1 to 12: 0 to 5: 1: 2 to 12: 0 to 10. a1 is preferably 1 to 9, and more preferably 1.5 to 7.5. b1 is preferably 0 to 3, more preferably 0 to 1. d1 is preferably from 2.5 to 10, and more preferably from 3.0 to 8.5. e1 is preferably from 0 to 5, more preferably from 0 to 3.

組成 The composition ratio of each element can be controlled by adjusting the compounding ratio of the raw material compounds when producing the sulfide-based inorganic solid electrolyte as described below.

The sulfide-based inorganic solid electrolyte may be non-crystalline (glass) or crystallized (glass-ceramic), or may be partially crystallized. For example, Li-PS-based glass containing Li, P and S, or Li-PS-based glass ceramic containing Li, P and S can be used.
Examples of the sulfide-based inorganic solid electrolyte include lithium sulfide (Li ₂ S), phosphorus sulfide (for example, diphosphorus pentasulfide (P ₂ S ₅ )), elemental phosphorus, elemental sulfur, sodium sulfide, hydrogen sulfide, and lithium halide (for example, LiI, LiBr, LiCl) and at least two or more of sulfides (for example, SiS ₂ , SnS, GeS ₂ ) of the element represented by M can be produced.

In Li-P-S based glass and Li-P-S based glass ceramics, the ratio of Li ₂ S and _P 2 _{S 5} _is, Li 2 _S: at a molar ratio of P 2 _{S 5,} preferably 60: 40 ~ 90:10, more preferably 68:32 to 78:22. By setting the ratio of Li ₂ S and P ₂ S ₅ to this range, the lithium ion conductivity can be increased. Specifically, the lithium ion conductivity can be preferably 1 × 10 ⁻⁴ S / cm or more, more preferably 1 × 10 ⁻³ S / cm or more. Although there is no particular upper limit, it is practical that it is 1 × 10 ⁻¹ S / cm or less.

As examples of specific sulfide-based inorganic solid electrolytes, combinations of raw materials are shown below. For example, Li ₂ S—P ₂ S ₅ , Li ₂ S—P ₂ S ₅ —LiCl, Li ₂ S—P ₂ S ₅ —H ₂ S, Li ₂ S—P ₂ S ₅ —H ₂ S—LiCl, Li ₂ S—LiI—P ₂ S ₅ , Li ₂ S—LiI—Li ₂ O—P ₂ S ₅ , Li ₂ S—LiBr—P ₂ S ₅ , Li ₂ S—Li ₂ O—P ₂ S ₅ , Li ₂ S—Li ₃ PO ₄ —P ₂ S ₅ , Li ₂ SP—P ₂ S ₅ —P ₂ O ₅ , Li ₂ SP—P ₂ S ₅ —SiS ₂ , Li ₂ SP—P ₂ S ₅ —SiS _{_{_{_{2 -LiCl, Li 2 S-P}}}} 2 S 5 -SnS, Li 2 S-P 2 S 5 -Al 2 S 3, Li 2 S-GeS 2, Li 2 S-GeS 2 -ZnS, Li 2 S-Ga _{_{_{_{2 S 3, Li 2 S-}}}} GeS 2 -Ga 2 S 3, Li 2 S-GeS 2 -P 2 S 5 _{_{_{_{Li 2 S-GeS 2 -Sb 2}}}} S 5, Li 2 S-GeS 2 -Al 2 S 3, Li 2 S-SiS 2, Li 2 S-Al 2 S 3, Li 2 S-SiS 2 -Al 2 S ₃ , Li ₂ S—SiS ₂ —P ₂ S ₅ , Li ₂ S—SiS ₂ —P ₂ S ₅ —LiI, Li ₂ S—SiS ₂ —LiI, Li ₂ S—SiS ₂ —Li ₄ SiO ₄ , Li ₂ S—SiS ₂ —Li ₃ PO ₄ , Li ₁₀ GeP ₂ S _{12 and the} like. However, the mixing ratio of each raw material does not matter. As a method for synthesizing a sulfide-based inorganic solid electrolyte material using such a raw material composition, for example, an amorphization method can be mentioned. Examples of the amorphization method include a mechanical milling method, a solution method, and a melt quenching method. This is because processing at normal temperature becomes possible, and the manufacturing process can be simplified.

(Ii) Oxide-based inorganic solid electrolyte The oxide-based inorganic solid electrolyte contains an oxygen atom (O), has ionic conductivity of a metal belonging to

Group

1 or 2 of the periodic table, and And a compound having an electronic insulating property are preferable.

Specific examples of the compound include, for example, Li _xa La _ya TiO ₃ [xa = 0.3 to 0.7, ya = 0.3 to 0.7] (LLT), Li _xb La _yb Zr _zb M ^bb _mb O _nb ( ^Mbb is at least one element of Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In and Sn, xb satisfies 5 ≦ xb ≦ 10, and yb satisfies 1 ≦ yb Satisfies ≦ 4, zb satisfies 1 ≦ zb ≦ 4, mb satisfies 0 ≦ mb ≦ 2, nb satisfies 5 ≦ nb ≦ 20), Li _xc _Byc M ^cc _zc O _nc (M ^cc is C, S, Al, Si, Ga, Ge, In and Sn are at least one or more elements, xc satisfies 0 ≦ xc ≦ 5, yc satisfies 0 ≦ yc ≦ 1, and zc satisfies 0 ≦ zc ≦ met 1, nc satisfies 0 ≦ nc ≦ 6.), Li xd ( _{_{l, Ga) yd (Ti,}} Ge) zd Si ad P md O nd ( provided that, 1 ≦ xd ≦ 3,0 ≦ yd ≦ 1,0 ≦ zd ≦ 2,0 ≦ ad ≦ 1,1 ≦ md ≦ 7, _{^{3 ≦ nd ≦ 13), Li}} (3-2xe) M ee xe D ee O (xe represents a number of 0 to ^0.1, ^{.D ee} ^{M ee} is representative of a divalent metal atom is a halogen atom or a Represents a combination of two or more halogen atoms.), Li _xf Si _yf O _zf (1 ≦ xf ≦ 5, 0 <yf ≦ 3, 1 ≦ zf ≦ 10), Li _xg S _yg O _zg (1 ≦ xg ≦ 3, 0 <yg ≦ 2, 1 ≦ zg ≦ 10), Li ₃ BO ₃ —Li ₂ SO ₄ , Li ₂ O—B ₂ O ₃ —P ₂ O ₅ , Li ₂ O—SiO ₂ , Li ₆ BaLa ₂ _{_{_{_{ta 2 O 12, Li 3 PO}}}} (4-3 / 2w) N w (w is w <1), LIS CON (Lithium super ionic conductor) type _Li 3.5 _Zn 0.25 GeO ₄ having a crystal structure, _La 0.55 _Li 0.35 _TiO 3 having a perovskite crystal structure, NASICON (Natrium super ionic conductor) type crystal structure LiTi ₂ P ₃ O ₁₂ , Li _{1 + xh + yh} (Al, Ga) _xh (Ti, Ge) _2-xh Si _yh P _3-yh O ₁₂ (where 0 ≦ xh ≦ 1, 0 ≦ yh ≦ 1), garnet Li ₇ La ₃ Zr ₂ O ₁₂ (LLZ) having a type crystal structure is exemplified. Further, a phosphorus compound containing Li, P and O is also desirable. For example, lithium phosphate (Li ₃ PO ₄ ), LiPON in which a part of oxygen of lithium phosphate is substituted by nitrogen, LiPOD ¹ (D ¹ is Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr , Nb, Mo, Ru, Ag, Ta, W, Pt, Au, etc.). Further, LiA ¹ ON (A ¹ is at least one selected from Si, B, Ge, Al, C, Ga, and the like) can also be preferably used.

The inorganic solid electrolyte is preferably a particle. In this case, the particle size of the inorganic solid electrolyte is not particularly limited. In terms of ionic conductivity, furthermore, processability and interface forming property, the particle diameter of the inorganic solid electrolyte is preferably 0.01 μm or more, more preferably 0.2 μm or more, and further preferably 0.3 μm or more. The particle diameter of the inorganic solid electrolyte is preferably 100 μm or less, more preferably 50 μm or less, further preferably 20 μm or less, further preferably 4 μm or less, and particularly preferably 2 μm or less.
The particle size of the inorganic solid electrolyte particles means an average particle size and can be determined as follows.
The inorganic solid electrolyte particles are diluted with water (heptane in the case of a substance unstable to water) to adjust a 1% by mass dispersion liquid in a 20 mL sample bottle. The dispersion sample after dilution is irradiated with 1 kHz ultrasonic wave for 10 minutes and used immediately after the test. Using this dispersion liquid sample, data was taken 50 times at a temperature of 25 ° C. using a laser diffraction / scattering type particle size distribution analyzer LA-920 (trade name, manufactured by HORIBA) using a quartz cell for measurement. Obtain the volume average particle size. For other detailed conditions, refer to the description of JIS Z 8828: 2013 “Particle size analysis-dynamic light scattering method” as necessary. Five samples are prepared for each level, and the average value is adopted.

(binder)
The binder contained in the solid electrolyte layer can be composed of various organic high molecular compounds (polymers). The binder enhances the binding property between the inorganic solid electrolyte particles and contributes to improvement in mechanical strength, ionic conductivity, and the like. The organic polymer compound constituting the binder may include a particulate one or a non-particulate one. From the viewpoint of further improving ion conductivity, a particulate binder is preferable. The primary particle diameter (volume average particle diameter) of the particulate binder is preferably from 10 to 1,000 nm, more preferably from 20 to 750 nm, further preferably from 30 to 500 nm, and still more preferably from 50 to 300 nm.

The binder may be composed of, for example, an organic polymer compound described below.

-Fluorine-containing resin-
Examples of the fluorinated resin include polytetrafluoroethylene (PTFE), polyvinylene difluoride (PVdF), and a copolymer of polyvinylene difluoride and hexafluoropropylene (PVdF-HFP).

-Hydrocarbon thermoplastic resin-
Examples of the hydrocarbon thermoplastic resin include polyethylene, polypropylene, styrene butadiene rubber (SBR), hydrogenated styrene butadiene rubber (HSBR), butylene rubber, acrylonitrile butadiene rubber, polybutadiene, and polyisoprene.

-(Meth) acrylic resin-
Examples of the (meth) acrylic resin include various (meth) acrylic monomers, (meth) acrylamide monomers, and copolymers of two or more of these monomers.
In addition, copolymers with other vinyl monomers are also preferably used. For example, a copolymer of methyl (meth) acrylate and styrene, a copolymer of methyl (meth) acrylate and acrylonitrile, and a copolymer of butyl (meth) acrylate, acrylonitrile and styrene, It is not limited to these. In the present specification, the copolymer may be any of a statistical copolymer and a periodic copolymer, and is preferably a random copolymer.

－Other resins－
Examples of other resins include polyurethane resins, polyurea resins, polyamide resins, polyimide resins, polyester resins, polyether resins, polycarbonate resins, and cellulose derivative resins.

When the solid electrolyte composition contains a binder, the content of the binder in the solid content of the solid electrolyte composition can be 1 to 20% by mass, preferably 2 to 15% by mass, more preferably 3 to 10% by mass. .

Among the above, a fluorine-containing resin, a hydrocarbon-based thermoplastic resin, a (meth) acrylic resin, a polyurethane resin, a polycarbonate resin, and a cellulose derivative resin are preferable, which have good affinity with an inorganic solid electrolyte, and A (meth) acrylic resin or a polyurethane resin is particularly preferred in that it has good flexibility and can show stronger binding with solid particles.
Commercially available products can be used as the above various resins. Moreover, it can also be prepared by a conventional method.
The number average molecular weight of the polymer constituting the binder is preferably from 1,000 to 1,000,000, and more preferably from 10,000 to 500,000, from the viewpoint of improving the binding between solid particles.
The organic polymer compound described above is an example, and the binder in the present invention is not limited to these forms.

(Lithium salt)
The solid electrolyte containing layer may contain a lithium salt (supporting electrolyte).
As the lithium salt, a lithium salt usually used for this kind of product is preferable, and there is no particular limitation. For example, lithium salts described in paragraphs 0082 to 0085 of JP-A-2015-088486 are preferable.
When the solid electrolyte containing layer contains a lithium salt, the content of the lithium salt is preferably at least 0.1 part by mass, more preferably at least 5 parts by mass, based on 100 parts by mass of the inorganic solid electrolyte. As a maximum, 50 mass parts or less are preferred, and 20 mass parts or less are more preferred.

(Ionic liquid)
The solid electrolyte containing layer may contain an ionic liquid in order to further improve the ionic conductivity. The ionic liquid is not particularly limited, but is preferably one that dissolves the above-described lithium salt from the viewpoint of effectively improving ionic conductivity. For example, a compound comprising a combination of the following cation and an anion is exemplified.

<Positive electrode active material layer, negative electrode active material layer>
The positive electrode active material layer and the negative electrode active material layer that constitute the laminated member of the present invention can be formed by ordinary constituent materials used in an all-solid secondary battery. The positive electrode active material layer contains a positive electrode active material, and the negative electrode active material layer contains a negative electrode active material. The positive electrode active material layer and the negative electrode active material layer preferably have the same configuration as the above-described solid electrolyte layer except that they include an active material.
That is, in the present invention, the positive electrode active material layer and the negative electrode active material layer are a composition (a positive electrode forming composition and a negative electrode forming composition; a composition in which a corresponding active material is added to the solid electrolyte composition described above. (Referred to collectively as a composition for forming an electrode)), and applied to a substrate to form the composition. The content of each component in the electrode forming composition can be appropriately adjusted depending on the purpose. For example, the content of the active material in the solid content of the electrode forming composition can be 20 to 95% by mass, and more preferably 30 to 90% by mass.

(Active material)
The shape of the active material is not particularly limited, but is preferably particulate. The particle size of the active material is not particularly limited as long as the above-mentioned particle size ratio is satisfied. The particle diameter of the active material is preferably 0.1 μm or more, more preferably 1 μm or more, and more preferably 2 μm or more from the viewpoints of improving dispersibility, increasing the contact area between solid particles, and reducing interface reactivity. Is more preferable. The particle size of the active material is preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less. The particle size of the active material means an average particle size, and can be determined in the same manner as the particle size of the inorganic solid electrolyte. When the particle size of the active material is equal to or less than the measurement limit of the particle size measuring device, the active material is dried if necessary, and then the particle size is measured by observation with a transmission electron microscope (TEM).

－Positive electrode active material－
The positive electrode active material is preferably one 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, an organic substance, an element such as sulfur, which can be combined with Li, or a composite of sulfur and a metal.
Among them, a transition metal oxide is preferably used as the positive electrode active material, and a transition metal oxide containing a transition metal element M ^a (at least one element selected from Co, Ni, Fe, Mn, Cu, and V). Are more preferred. In addition, the transition metal oxide includes an element M ^b (an element of Group 1 (Ia), an element of Group 2 (IIa), Al, Ga, In, Ge, Sn, Pb, Sb, Bi, Si, P or B). The mixing amount is preferably 0 ~ 30 mol% relative to the amount of the transition metal element ^{M a (100mol%).} Those synthesized by mixing such that the molar ratio of Li / Ma becomes 0.3 to 2.2 are more preferable.
Specific examples of the transition metal oxide include (MA) a transition metal oxide having a layered rock salt type structure, (MB) a transition metal oxide having a spinel type structure, (MC) a lithium-containing transition metal phosphate compound, (MD) And (ME) lithium-containing transition metal silicate compounds.

(MA) As specific examples of the transition metal oxide having a layered rock salt type structure, LiCoO ₂ (lithium cobaltate [LCO]), LiNi ₂ O ₂ (lithium nickelate), LiNi _0.85 Co _0.10 Al 0.1 _{. 05} O ₂ (lithium nickel cobalt aluminum oxide [NCA]), LiNi _1/3 Co _1/3 Mn _1/3 O ₂ (lithium nickel manganese cobalt oxide [NMC]) and LiNi _0.5 Mn _0.5 O ₂ ( Lithium manganese nickelate).
(MB) Specific examples of the transition metal oxide having a spinel structure include LiMn ₂ O ₄ (LMO), LiCoMnO ₄ , Li ₂ FeMn ₃ O ₈ , Li ₂ CuMn ₃ O ₈ , Li ₂ CrMn ₃ O _8, and Li. ₂ NiMn ₃ O ₈ .
Examples of the (MC) lithium-containing transition metal phosphate compound include olivine-type iron phosphates such as LiFePO ₄ and Li ₃ Fe ₂ (PO ₄ ) ₃ , iron pyrophosphates such as LiFeP ₂ O ₇ , and LiCoPO _4. And monoclinic nasicon-type vanadium phosphate salts such as Li ₃ V ₂ (PO ₄ ) ₃ (lithium vanadium phosphate).
(MD) as the lithium-containing transition metal halogenated phosphate compound, for _example, Li 2 FePO ₄ F such fluorinated phosphorus iron _salt, Li 2 MnPO ₄ hexafluorophosphate manganese salts such as F and _Li 2 CoPO ₄ F And the like, such as cobalt fluorophosphates.
(ME) Examples of the lithium-containing transition metal silicate compound include Li ₂ FeSiO ₄ , Li ₂ MnSiO _4, and Li ₂ CoSiO ₄ .
In the present invention, a transition metal oxide having a (MA) layered rock salt type structure is preferable, and LCO or NMC is more preferable.

(4) In order to make the positive electrode active material have a desired particle size, an ordinary pulverizer or a classifier may be used. The positive electrode active material obtained by the firing method may be used after washing with water, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent.

The positive electrode active material may be used alone or in combination of two or more.
When the positive electrode active material layer is formed, the mass (mg) (basis weight) of the positive electrode active material per unit area (cm ² ) of the positive electrode active material layer is not particularly limited. It can be determined appropriately according to the designed battery capacity.

-Negative electrode active material-
The negative electrode active material is preferably one capable of reversibly inserting and releasing lithium ions. The material is not particularly limited as long as it has the above characteristics, carbonaceous materials, metal oxides such as tin oxide, silicon oxide, metal composite oxides, lithium alone and lithium alloys such as lithium aluminum alloy, and , Sn, Si, Al, In and other metals that can form an alloy with lithium. Among them, a carbonaceous material or a lithium composite oxide is preferably used from the viewpoint of reliability. Further, as the metal composite oxide, it is preferable that lithium can be inserted and extracted. The material is not particularly limited, but preferably contains titanium and / or lithium from the viewpoint of high current density charge / discharge characteristics.

炭素 A carbonaceous material used as a negative electrode active material is a material substantially composed of carbon. For example, various synthetics such as petroleum pitch, carbon black such as acetylene black (AB), graphite (artificial graphite such as natural graphite and vapor-grown graphite), and PAN (polyacrylonitrile) -based resin or furfuryl alcohol resin. A carbonaceous material obtained by firing a resin can be used. Further, various carbon fibers such as PAN-based carbon fiber, cellulose-based carbon fiber, pitch-based carbon fiber, vapor-grown carbon fiber, dehydrated PVA (polyvinyl alcohol) -based carbon fiber, lignin carbon fiber, glassy carbon fiber, and activated carbon fiber. , Mesophase microspheres, graphite whiskers, flat graphite, and the like.

As the metal oxide and the metal composite oxide applied as the negative electrode active material, an amorphous oxide is particularly preferable, and chalcogenite which is a reaction product of a metal element and an element of Group 16 of the periodic table is also preferably used. Can be The term “amorphous” as used herein means an X-ray diffraction method using CuKα rays, which has a broad scattering band having an apex in a range of 20 ° to 40 ° in 2θ value, and a crystalline diffraction line. May be provided.

Among the compound group consisting of the above-mentioned amorphous oxide and chalcogenide, an amorphous oxide of a metalloid element and a chalcogenide are more preferable, and an element of Group 13 (IIIB) to Group 15 (VB) of the periodic table, Al , Ga, Si, Sn, Ge, Pb, Sb and Bi are particularly preferably oxides composed of one or a combination of two or more thereof, and chalcogenides. Specific examples of preferable amorphous oxides and chalcogenides include, for example, Ga ₂ O ₃ , SiO, GeO, SnO, SnO ₂ , PbO, PbO ₂ , Pb ₂ O ₃ , Pb ₂ O ₄ , Pb ₃ O ₄ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₈ Bi ₂ O ₃ , Sb ₂ O ₈ Si ₂ O ₃ , Bi ₂ O ₄ , SnSiO ₃ , GeS, SnS, SnS ₂ , PbS, PbS ₂ , Sb ₂ S ₃ , Sb ₂ S ₅ and SnSiS ₃ are preferred. Further, these may be a composite oxide with lithium oxide, for example, Li ₂ SnO ₂ .

It is also preferable that the negative electrode active material contains a titanium atom. More specifically, Li ₄ Ti ₅ O ₁₂ (lithium titanate [LTO]) is excellent in rapid charge / discharge characteristics due to small volume fluctuation at the time of occlusion and release of lithium ions. This is preferable in that the life of the battery can be improved.

において In the present invention, it is also preferable to use a Si-based negative electrode. Generally, a Si negative electrode can store more Li ions than a carbon negative electrode (such as graphite and acetylene black). That is, the storage amount of Li ions per unit mass increases. Therefore, the battery capacity can be increased. As a result, there is an advantage that the battery driving time can be extended.

通常 In order to make the negative electrode active material have a predetermined particle size, an ordinary pulverizer or a classifier is used. For example, mortars, ball mills, sand mills, vibrating ball mills, satellite ball mills, planetary ball mills, swirling air jet mills, sieves, and the like are preferably used. At the time of pulverization, wet pulverization in the presence of water or an organic solvent such as methanol can also be performed if necessary. Classification is preferably performed to obtain a desired particle size. The classification method is not particularly limited, and a sieve, an air classifier, or the like can be used as necessary. Classification can be performed both in a dry process and in a wet process.

化学 The chemical formula of the compound obtained by the above firing method can be calculated from inductively coupled plasma (ICP) emission spectroscopy as a measuring method, and from the mass difference of powder before and after firing as a simple method.

The negative electrode active material may be used alone or in combination of two or more.
When the negative electrode active material layer is formed, the mass (mg) (basis weight) of the negative electrode active material per unit area (cm ² ) of the negative electrode active material layer is not particularly limited. It can be determined appropriately according to the designed battery capacity.

The surfaces of the positive electrode active material and the negative electrode active material may be coated with another metal oxide. In addition, the surface of the particles of the positive electrode active material or the negative electrode active material may be subjected to a surface treatment with an active ray or an active gas (such as plasma) before and after the surface coating.
Further, in the present invention, the positive electrode active material layer and the negative electrode active material layer may contain a conductive auxiliary. The conductive assistant is not particularly limited, and those known as general conductive assistants can be used. For example, electron conductive materials such as natural graphite, graphite such as artificial graphite, carbon black such as acetylene black, Ketjen black, furnace black, amorphous carbon such as needle coke, vapor grown carbon fiber or carbon nanotube Carbon fibers such as graphene or fullerene; metal powder such as copper and nickel; metal fibers; and conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene, and polyphenylene derivatives. May be used.

において In the laminated member of the present invention, the thickness of each of the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer is not particularly limited. The thickness of each layer is preferably 10 μm to 500 μm, more preferably 20 to 400 μm, and still more preferably 20 to 200 μm, in consideration of the dimensions of a general all-solid secondary battery. In addition, each of the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer may be a single layer or a multilayer. In the case of a multilayer, it is preferable that the thickness of the entire multilayer be within the above preferred range.

積層 In the laminated member of the present invention, the above-described negative electrode active material layer can be a lithium metal layer. Examples of the lithium metal layer include a layer formed by depositing or molding lithium metal powder, a lithium foil, and a lithium vapor deposition film. Regardless of the thickness of the negative electrode active material layer, the thickness of the lithium metal layer can be, for example, 1 to 500 μm.

<Current collector layer>
The current collector layer used for the laminated member of the present invention is preferably an electron conductor. It is preferable that at least one of the current collector layers used in the laminated member of the present invention is made of a metal foil. It is preferable that the slurry for forming each layer is sequentially or simultaneously applied onto the metal foil.
When this metal foil is used as a positive electrode current collector layer, its constituent materials include aluminum, an aluminum alloy, stainless steel, nickel, and titanium. Further, those obtained by treating the surface of aluminum or stainless steel with carbon, nickel, titanium or silver (thin films formed) are also preferable. Among them, aluminum and aluminum alloy are more preferable.
When the metal foil is used as a negative electrode current collector layer, its constituent materials include aluminum, copper, copper alloy, stainless steel, nickel, and titanium. Further, those obtained by treating the surface of aluminum, copper, copper alloy or stainless steel with carbon, nickel, titanium or silver are also preferable. Above all, the constituent material of the negative electrode current collector layer is more preferably aluminum, copper, a copper alloy, or stainless steel.

The shape of the current collector layer made of a metal foil is usually a film sheet, but a net, a punched material, a lath, a porous material, a foam, a molded product of a fiber group, and the like may also be used. Can be.

When the laminated member of the present invention has, for example, the laminated structure of (a) and (b), as described above, the second current collector layer contains the slurry containing the constituent material of the second current collector layer. It is formed by using. This slurry may be in a form containing a powder of a constituent material of the second current collector layer. In the above laminated structure (a), the second current collector layer is a negative electrode current collector layer, and as a conductive material, for example, powder (particles) of aluminum, copper, copper alloy, stainless steel, nickel, titanium, or the like is used. The second current collector layer can be formed by applying the contained slurry. In the above-described laminated structure (b), the second current collector layer is a positive electrode active material layer, and a slurry containing a powder of, for example, aluminum, an aluminum alloy, stainless steel, nickel, and titanium as a conductive material is used. Can be used to form a second current collector layer.
Further, the second current collector layer may be configured to contain carbon black as a conductive material. That is, it is also preferable to apply and form the current collector layer using a slurry obtained by mixing carbon black and a dispersion medium.
When the laminated member of the present invention has the laminated structure of the above (c), preferably, all of the current collector layers other than the current collector layer composed of the metal foil as the base material contain the constituent material of the current collector layer It is formed by wet-on-wet coating using a slurry to be formed. The constituent material of the current collector layer can be appropriately selected from, for example, the constituent materials described above in consideration of the form such as a monopolar type and a bipolar type.
The slurry for forming the current collector layer also preferably contains a binder. The preferred form of the binder is the same as the binder described above. By including the binder, the binding property of the constituent material of the current collector layer can be increased, the adhesion to the active material layer can be increased, and the resistance during charge and discharge of the battery can be further reduced.
The content of the constituent material of the current collector layer in the slurry may be appropriately adjusted depending on the purpose. For example, the content of the conductive material in the solid content of the slurry can be 50% by mass or more, preferably 70% by mass or more, and more preferably 80% by mass or more. When the slurry contains a binder, the conductive material / binder (mass ratio) is preferably 3/1 to 50/1, more preferably 5/1 to 30/1, and more preferably 7/1 to 20/1. / 1 is more preferable.

厚み The thickness of the current collector layer is not particularly limited, but is preferably 1 to 500 μm, more preferably 2 to 300 μm, and further preferably 2 to 200 μm.

において In the production method of the present invention, it is preferable that the types of the dispersion medium used in the slurry for forming the solid electrolyte layer, the positive electrode active material layer, the negative electrode active material layer, and the current collector layer are the same.

[Method of manufacturing all solid state secondary battery]
The method for manufacturing an all-solid secondary battery of the present invention is a method of obtaining the laminated member of the present invention by the above-described manufacturing method of the present invention, and obtaining an all-solid secondary battery using the laminated member. In the method for producing an all-solid secondary battery of the present invention, a general all-solid secondary battery production process may be applied except for using the laminated member of the present invention. Although the laminated member of the present invention operates as a secondary battery as it is, usually, the laminated member of the present invention is housed in an appropriate housing (enclosed in a housing or put in a coin case or the like). The pressurized state is assumed to be an all solid state secondary battery.
The housing may be made of metal or resin (plastic). When a metallic material is used, for example, an aluminum alloy or a stainless steel material can be used. It is preferable that the metallic casing is divided into a casing on the positive electrode side and a casing on the negative electrode side, and electrically connected to the positive electrode current collector and the negative electrode current collector, respectively. It is preferable that the housing on the positive electrode side and the housing on the negative electrode side are joined and integrated via a gasket for preventing short circuit.

<Initialization>
It is preferable to initialize the all-solid-state secondary battery manufactured as described above after manufacturing or before use. The initialization is not particularly limited, and can be performed, for example, by performing initial charge / discharge in a state where the press pressure is increased, and then releasing the pressure until the general use pressure of the all solid state secondary battery is reached.

Hereinafter, an embodiment of an all solid state secondary battery (lithium ion secondary battery) obtained by the method for manufacturing an all solid state secondary battery of the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view schematically illustrating the all-solid-state secondary battery, in which the description of the housing and the like is omitted, and the laminated member (corresponding to the laminated structure of the above (a) and (b)) of the present invention. 2 shows the configuration. When viewed from the negative electrode side, the all-solid secondary battery 103 includes a negative electrode current collector layer 11, a negative electrode active material layer 12, a solid electrolyte layer 13, a positive electrode active material layer 14, and a positive electrode current collector layer 15 in this order. Each layer is in contact with each other and has an adjacent structure. By employing such a structure, at the time of charging, electrons (e ⁻ ) are supplied to the negative electrode side, and lithium ions (Li ⁺ ) are accumulated therein. On the other hand, at the time of discharging, lithium ions (Li ⁺ ) accumulated in the negative electrode are returned to the positive electrode side, and electrons are supplied to the operating portion 16. In the illustrated example, a light bulb is employed as a model for the operating portion 16, and this is turned on by discharge.

全 The all-solid secondary battery obtained by the production method of the present invention can be applied to various uses. Although there is no particular limitation on the application mode, for example, when mounted on an electronic device, for example, a notebook computer, a pen input computer, a mobile computer, an electronic book player, a mobile phone, a cordless phone handset, a pager, a handy terminal, a mobile fax, and a mobile phone Copy, portable printer, headphone stereo, video movie, LCD television, handy cleaner, portable CD, mini disk, electric shaver, transceiver, electronic organizer, calculator, portable tape recorder, radio, backup power supply, memory card, and the like. Other consumer products include automobiles (electric vehicles, etc.), electric vehicles, motors, lighting fixtures, toys, game machines, road conditioners, watches, strobes, cameras, medical equipment (pacemakers, hearing aids, shoulder massagers, etc.). . Furthermore, it can be used for various military purposes and space applications. Further, it can be combined with a solar cell.

本 Hereinafter, the present invention will be described in more detail based on examples. It should be noted that the present invention is not construed as being limited thereto.

[Synthesis of sulfide-based inorganic solid electrolyte (Li-PS-based glass)]
The sulfide-based inorganic solid electrolyte is manufactured by T.I. Ohtomo, A .; Hayashi, M .; Tatsusumisago, Y .; Tsuchida, S .; Hama, K .; Kawamoto, Journal of Power Sources, 233, (2013), pp 231-235 and A.I. Hayashi, S .; Hama, H .; Morimoto, M .; Tatsusumisago, T .; Minami, Chem. Lett. , (2001), pp872-873.

Specifically, in a glove box under an argon atmosphere (dew point -70 ° C.), 2.42 kg of lithium sulfide (Li ₂ S, manufactured by Aldrich, purity> 99.98%) and diphosphorus pentasulfide (P ₂ S) were used. _5. Aldrich Co., purity> 99%) 3.90 kg were weighed, placed in an agate mortar, and mixed for 5 minutes using the agate mortar. Note that Li ₂ S and P ₂ S ₅ were in a molar ratio of Li ₂ S: P ₂ S ₅ = 75: 25.
66 zirconia beads having a diameter of 5 mm were placed in a 45 mL zirconia container (manufactured by Fritsch), and the entire mixture of lithium sulfide and diphosphorus pentasulfide was charged therein. The container was sealed under an argon atmosphere. The container was set in a planetary ball mill P-7 (trade name) manufactured by Fritsch, and mechanical milling was performed at a temperature of 25 ° C. and a rotation speed of 510 rpm for 20 hours to obtain a yellow powdered sulfide-based inorganic solid electrolyte (Li-PS-based). Glass, also referred to as "LPS".) 6.20 g was obtained.

[Preparation of slurry for forming solid electrolyte layer]
130 zirconia beads having a diameter of 5 mm are put into a 45 mL zirconia container (manufactured by Fritsch), 3.0 g of LPS, and 0.09 g of styrene-butadiene rubber (SBR, average primary particle size 100 nm, the same applies hereinafter) as a binder, 9.0 g of toluene was added as a dispersion medium. A container was set in a planetary ball mill P-7 (trade name) manufactured by Fritsch, and mixed at a temperature of 25 ° C. and a rotation speed of 100 rpm for 30 minutes to form a solid electrolyte layer containing LPS having a particle size of 2.0 μm. A slurry for forming a solid electrolyte layer was prepared.

[Preparation of slurry for forming positive electrode active material layer]
180 zirconia beads having a diameter of 5 mm were put into a 45 mL zirconia container (made by Fritsch), 2.8 g of LPS synthesized above, 0.1 g of SBR as a binder, and 12.3 g of toluene as a dispersion medium were put therein. . The container was set in a planetary ball mill P-7 (trade name) manufactured by Fritsch, and mixed at a temperature of 25 ° C. and a rotation speed of 300 rpm for 2 hours. Thereafter, 7.0 g of NMC (LiNi _0.33 Co _0.33 Mn _0.33 O ₂ (manufactured by Aldrich)) as an active material and 0.2 g of acetylene black (manufactured by Denka Corporation) as a conductive aid were placed in a container. Then, the container was set in a planetary ball mill P-7, and mixing was continued at a temperature of 25 ° C. and a rotation speed of 100 rpm for 10 minutes to prepare a slurry for forming a positive electrode active material layer.

[Preparation of slurry for forming negative electrode active material layer]
180 zirconia beads having a diameter of 5 mm are put into a 45 mL zirconia container (made by Fritsch), 2.8 g of the LPS-based glass synthesized above, 0.2 g of SBS as a binder, and 12.3 g of heptane as a dispersion medium. did. The container was set in a planetary ball mill P-7 manufactured by Fritsch, and mixed at a temperature of 25 ° C. and a rotation speed of 300 rpm for 2 hours. Thereafter, 7.0 g of graphite as an active material was charged into the container, and similarly, the container was set in a planetary ball mill P-7, and mixed at a temperature of 25 ° C. and a rotation speed of 200 rpm for 15 minutes to obtain a slurry for forming a negative electrode active material layer. Prepared.

[Preparation of slurry for forming current collector layer]
180 zirconia beads having a diameter of 5 mm were charged into a 45 mL zirconia container (Fritsch), 6.0 g of carbon black, 0.06 g of SBR as a binder, and 4.0 g of heptane as a dispersion medium. The container was set in a planetary ball mill P-7 manufactured by Fritsch, and mixed at a temperature of 25 ° C. and a rotation speed of 300 rpm for 2 hours to prepare a slurry for forming a current collector layer.

[Production of laminated member for all solid state secondary battery]
<Example 1>
The slurry prepared above for forming a positive electrode active material layer was applied on an aluminum foil (positive electrode current collector, thickness: 20 μm) using an applicator (trade name: SA-201 Baker-type applicator, manufactured by Tester Sangyo Co., Ltd.) at 30 mg / It was applied so as to have a basis weight of ² cm2, and a coating film (a positive electrode active material layer precursor coating film) was formed on the positive electrode current collector layer made of aluminum foil.
In the state where the residual solvent amount of the positive electrode active material layer precursor coating film is 5% by mass, the solid electrolyte layer forming slurry is applied onto the positive electrode active material layer precursor coating film so as to have a basis weight of 8 mg / cm ² by the applicator. This was applied to form a coating film (solid electrolyte layer precursor coating film) on the positive electrode active material layer precursor coating film.
With the residual solvent amount of the solid electrolyte layer precursor coating film being 5% by mass, the negative electrode active material layer forming slurry was applied on the solid electrolyte layer precursor coating film by the above-mentioned applicator so as to have a basis weight of 20 mg / cm ^2. Then, a coating film (a negative electrode active material layer precursor coating film) was formed on the solid electrolyte layer precursor coating film.
With the residual solvent amount of the negative electrode active material layer precursor coating film being 5% by mass, the current collector layer forming slurry was applied on the negative electrode active material layer precursor coating film by the above-mentioned applicator to have a basis weight of 10 mg / cm ^2. To form a coating film (second current collector layer precursor coating film) on the negative electrode active material layer precursor coating film.
The laminate thus obtained by wet-on-wet coating was heated at 120 ° C. for 1 hour to remove the dispersion medium, thereby obtaining a laminated member for an all-solid-state secondary battery of Example 1 having the above-described laminated structure (a). Was.
In the laminated member for an all solid state secondary battery of Example 1, the thickness of the positive electrode active material layer was 100 μm, the thickness of the solid electrolyte layer was 20 μm, the thickness of the negative electrode active material layer was 80 μm, and the thickness of the second current collector layer was The thickness was 20 μm.

<Example 2>
A slurry for forming a positive electrode active material layer, a slurry for forming a solid electrolyte layer, a slurry for forming a negative electrode active material layer, and a slurry for forming a current collector layer are formed on an aluminum foil (positive electrode current collector, 20 μm thick) in this order. Simultaneous multi-layer coating was performed using a multi-layer dedicated greaser so that the coating films were laminated.
The laminate thus obtained by wet-on-wet coating was heated at 120 ° C. for 2 hours to remove the dispersion medium, thereby obtaining a laminate member for an all-solid-state secondary battery of Example 2 having the above-described laminate structure (a). Was.
In the laminated member for an all-solid-state secondary battery of Example 2, the thickness of the positive electrode active material layer was 100 μm, the thickness of the solid electrolyte layer was 20 μm, the thickness of the negative electrode active material layer was 80 μm, and the thickness of the second current collector layer was The thickness was 20 μm.

<Example 3>
In Example 1, after forming the second current collector layer precursor coating film, the positive electrode active material layer forming slurry was mixed with the above-mentioned slurry in a state where the residual solvent amount of the second current collector layer precursor coating film was 5% by mass. The solution was applied with an applicator so as to have a basis weight of 30 mg / cm ² , and a coating film (second positive electrode active material layer precursor coating film) was formed on the second current collector layer precursor coating film.
With the residual solvent amount of the second positive electrode active material layer precursor coating film being 5% by mass, the solid electrolyte layer forming slurry was applied on the second positive electrode active material layer precursor coating film by the above-mentioned applicator with a basis weight of 8 mg / cm ² . And a coating film (second solid electrolyte layer precursor coating film) was formed on the second positive electrode active material layer precursor coating film.
With the amount of the residual solvent in the second solid electrolyte layer precursor coating film being 5% by mass, the negative electrode active material layer forming slurry was applied onto the second solid electrolyte layer precursor coating film by the above-mentioned applicator with a basis weight of 20 mg / cm ^2. Thus, a coating film (second negative electrode active material layer precursor coating film) was formed on the second solid electrolyte layer precursor coating film.
With the residual solvent amount of the second negative electrode active material layer precursor coating film being 5% by mass, a slurry for forming a current collector layer was applied onto the second negative electrode active material layer precursor coating film by the above-mentioned applicator at a basis weight of 10 mg / cm ² . To form a coating film (third current collector layer precursor coating film) on the second negative electrode active material layer precursor coating film.
The laminate obtained by wet-on-wet coating in this manner is heated at 120 ° C. for 2 hours to remove the dispersion medium, and has a laminated structure in which two laminating units are stacked (an embodiment of the above-described laminated structure (c)). A laminated member for an all-solid secondary battery of Example 3 was obtained. The laminated member for an all solid state secondary battery of Example 3 is of a bipolar type.
In the all-solid-state secondary battery laminated member of Example 3, the thickness of each layer is the same as that of Example 1.

<Example 4>
In Example 3, after forming the third current collector layer precursor coating film, the slurry for forming a positive electrode active material layer was subjected to the above-mentioned slurry in a state where the residual solvent amount of the third current collector layer precursor coating film was 5% by mass. The resultant was applied with an applicator so as to have a basis weight of 30 mg / cm ² to form a coating film (third positive electrode active material layer precursor coating film) on the third current collector layer precursor coating film.
With the residual solvent amount of the third positive electrode active material layer precursor coating film being 5% by mass, the solid electrolyte layer forming slurry was applied onto the third positive electrode active material layer precursor coating film by the above-mentioned applicator with a basis weight of 8 mg / cm ² . To form a coating film (third solid electrolyte layer precursor coating film) on the positive electrode active material layer precursor coating film.
With the residual solvent amount of the third solid electrolyte layer precursor coating film being 5% by mass, the negative electrode active material layer forming slurry was applied onto the third solid electrolyte layer precursor coating film by the above-mentioned applicator with a basis weight of 20 mg / cm ^2. Thus, a coating film (third negative electrode active material layer precursor coating film) was formed on the third solid electrolyte layer precursor coating film.
With the residual solvent amount of the third negative electrode active material layer precursor coating film being 5% by mass, a current collector layer forming slurry was applied on the third negative electrode active material layer precursor coating film by the above-mentioned applicator at a basis weight of 10 mg / cm ² . To form a coating film (fourth current collector layer precursor coating film) on the third negative electrode active material layer precursor coating film.
The laminate obtained by wet-on-wet coating in this manner is heated at 120 ° C. for 2 hours to remove the dispersion medium, and has a laminate structure in which three lamination units are stacked (an embodiment of the laminate structure (c) described above). A laminated member for an all-solid secondary battery of Example 4 was obtained. The laminated member for an all solid state secondary battery of Example 3 is of a bipolar type.
In the laminated member for an all-solid-state secondary battery of Example 4, the thickness of each layer is the same as that of Example 1.

<Example 5>
In Example 4, after forming the fourth current collector layer precursor coating film, the slurry for forming a positive electrode active material layer was subjected to the above-mentioned slurry in a state where the residual solvent amount of the fourth current collector layer precursor coating film was 5% by mass. The solution was applied with an applicator so as to have a basis weight of 30 mg / cm ² to form a coating film (fourth positive electrode active material layer precursor coating film) on the fourth current collector layer precursor coating film.
With the residual solvent amount of the fourth positive electrode active material layer precursor coating film being 5% by mass, the solid electrolyte layer forming slurry was applied on the fourth positive electrode active material layer precursor coating film by the above-mentioned applicator with a basis weight of 8 mg / cm ² . To form a coating film (fourth solid electrolyte layer precursor coating film) on the positive electrode active material layer precursor coating film.
With the residual solvent amount of the fourth solid electrolyte layer precursor coating film being 5% by mass, a slurry for forming a negative electrode active material layer was applied onto the fourth solid electrolyte layer precursor coating film by the above-mentioned applicator with a basis weight of 20 mg / cm ^2. Thus, a coating film (fourth negative electrode active material layer precursor coating film) was formed on the fourth solid electrolyte layer precursor coating film.
With the residual solvent amount of the fourth negative electrode active material layer precursor coating film being 5% by mass, a current collector layer forming slurry was applied onto the fourth negative electrode active material layer precursor coating film by the above-described applicator at a basis weight of 10 mg / cm ² . And a coating film (fifth current collector layer precursor coating film) was formed on the fourth negative electrode active material layer precursor coating film.
The laminate thus obtained by wet-on-wet coating is heated at 120 ° C. for 2 hours to remove the dispersion medium, and has a laminated structure in which four laminating units are stacked (an embodiment of the laminated structure (c) described above). A laminated member for an all solid state secondary battery of Example 5 was obtained. The laminated member for an all solid state secondary battery of Example 3 is of a bipolar type.
In the laminated member for an all-solid-state secondary battery of Example 5, the thickness of each layer is the same as that of Example 1.

<Example 6>
Example 1 was the same as Example 1 except that the binder (SBR, particulate, 0.06 g) used in the slurry for forming the current collector layer was replaced with a binder (S-SBR (solution-polymerized styrene-butadiene rubber), 0.06 g). Then, a laminated member for an all-solid-state secondary battery of Example 6 was obtained in the same manner as in Example 1. S-SBR is soluble in heptane.

<Example 7>
In Example 1, LPS was replaced with LLZ: Li ₇ La ₃ Zr ₂ O ₁₂ (lithium lanthanum zirconate having an average particle size of 5.0 μm, manufactured by Toshima Seisakusho), which is an oxide-based inorganic solid electrolyte.
A laminated member for an all-solid-state secondary battery of Example 8 was obtained in the same manner as in Example 1 except for changing the above.

<Example 8>
The slurry for forming a negative electrode active material layer prepared above was applied to a copper foil (negative electrode current collector, thickness: 20 μm) using an applicator (trade name: SA-201 Baker-type applicator, manufactured by Tester Sangyo Co., Ltd.) at a concentration of 20 mg / The resultant was applied so as to have a basis weight of ² cm ² , and a coating film (a negative electrode active material layer precursor coating film) was formed on the negative electrode current collector layer made of copper foil.
In the state where the residual solvent amount of the negative electrode active material layer precursor coating film is 5% by mass, the solid electrolyte layer forming slurry is applied onto the negative electrode active material layer precursor coating film so as to have a basis weight of 8 mg / cm ² by the applicator. This was applied to form a coating film (solid electrolyte layer precursor coating film) on the negative electrode active material layer precursor coating film.
In a state where the residual solvent amount of the solid electrolyte layer precursor coating film is 5% by mass, a slurry for forming a positive electrode active material layer is applied on the solid electrolyte layer precursor coating film by the above-mentioned applicator so as to have a basis weight of 30 mg / cm ^2. Then, a coating film (a positive electrode active material layer precursor coating film) was formed on the solid electrolyte layer precursor coating film.
In the state where the residual solvent amount of the positive electrode active material layer precursor coating film is 5% by mass, the current collector layer forming slurry is applied on the positive electrode active material layer precursor coating film by the above-mentioned applicator to a basis weight of 10 mg / cm ^2. To form a coating film (second current collector layer precursor coating film) on the positive electrode active material layer precursor coating film.
The laminate thus obtained by wet-on-wet coating was heated at 120 ° C. for 2 hours to remove the dispersion medium, thereby obtaining a laminated member for an all-solid secondary battery of Example 8 having the above-described laminated structure (b). Was.
In the all-solid-state secondary battery laminated member of Example 8, the thickness of each layer formed by application is the same as that of Example 1.

<Example 9>
A slurry for forming a negative electrode active material layer, a slurry for forming a solid electrolyte layer, a slurry for forming a positive electrode active material layer, and a slurry for forming a current collector layer are formed on a copper foil (a negative electrode current collector, having a thickness of 20 μm) in this order. Simultaneous multi-layer coating was performed using a multi-layer dedicated greaser so that the coating films were laminated.
The laminate thus obtained by wet-on-wet coating was heated at 120 ° C. for 2 hours to remove the dispersion medium, thereby obtaining a laminated member for an all-solid-state secondary battery of Example 9 having the above-mentioned (b) laminated structure. Was.
In the all-solid-state secondary battery laminated member of Example 9, the thickness of each layer formed by coating is the same as that of Example 8.

<Example 10>
In Example 8, after forming the second current collector layer precursor coating film, the slurry for forming a negative electrode active material layer was coated with the above-mentioned slurry in a state where the residual solvent amount of the second current collector layer precursor coating film was 5% by mass. It was applied by an applicator so as to have a basis weight of 20 mg / cm ² , and a coating film (second negative electrode active material layer precursor coating film) was formed on the second current collector layer precursor coating film.
With the residual solvent amount of the second negative electrode active material layer precursor coating film being 5% by mass, the solid electrolyte layer forming slurry was applied on the second negative electrode active material layer precursor coating film by the above-mentioned applicator with a basis weight of 8 mg / cm ² . To form a coating film (second solid electrolyte layer precursor coating film) on the second negative electrode active material layer precursor coating film.
With the residual solvent amount of the second solid electrolyte layer precursor coating film being 5% by mass, the positive electrode active material layer forming slurry was applied on the second solid electrolyte layer precursor coating film by the above-mentioned applicator with a basis weight of 30 mg / cm ^2. Thus, a coating film (second positive electrode active material layer precursor coating film) was formed on the second solid electrolyte layer precursor coating film.
With the residual solvent amount of the second positive electrode active material layer precursor coating film being 5% by mass, a current collector layer forming slurry was applied on the second positive electrode active material layer precursor coating film by the above-mentioned applicator at a basis weight of 10 mg / cm ² . To form a coating film (third current collector layer precursor coating film) on the second positive electrode active material layer precursor coating film.
The laminate obtained by wet-on-wet coating in this manner is heated at 120 ° C. for 2 hours to remove the dispersion medium, and has a laminated structure in which two laminating units are stacked (an embodiment of the above-described laminated structure (c)). A laminated member for an all solid state secondary battery of Example 10 was obtained. The laminated member for an all solid state secondary battery of Example 10 is of a bipolar type.
In the laminated member for an all solid state secondary battery of Example 10, the thickness of each layer is the same as that of Example 8.

<Example 11>
In Example 10, after forming the third current collector layer precursor coating film, the slurry for forming a negative electrode active material layer was subjected to the above-mentioned slurry in a state where the residual solvent amount of the third current collector layer precursor coating film was 5% by mass. It was applied so as to have a basis weight of 20 mg / cm ² by an applicator to form a coating film (third negative electrode active material layer precursor coating film) on the third current collector layer precursor coating film.
In a state where the amount of the residual solvent in the third negative electrode active material layer precursor coating film is 5% by mass, the solid electrolyte layer forming slurry is applied on the third negative electrode active material layer precursor coating film by the above-mentioned applicator with a basis weight of 8 mg / cm ² . And a coating film (third solid electrolyte layer precursor coating film) was formed on the third negative electrode active material layer precursor coating film.
In a state where the amount of the residual solvent in the third solid electrolyte layer precursor coating film is 5% by mass, the slurry for forming a positive electrode active material layer is formed on the third solid electrolyte layer precursor coating film with a basis weight of 30 mg / cm ² by the applicator. Thus, a coating film (third positive electrode active material layer precursor coating film) was formed on the third solid electrolyte layer precursor coating film.
With the residual solvent amount of the third positive electrode active material layer precursor coating film being 5% by mass, a current collector layer forming slurry was applied on the third positive electrode active material layer precursor coating film by the above-mentioned applicator at a basis weight of 10 mg / cm ² . To form a coating film (fourth current collector layer precursor coating film) on the third positive electrode active material layer precursor coating film.
The laminate obtained by wet-on-wet coating in this manner is heated at 120 ° C. for 2 hours to remove the dispersion medium, and has a laminate structure in which three lamination units are stacked (an embodiment of the laminate structure (c) described above). A laminated member for an all-solid secondary battery of Example 11 was obtained. The laminated member for an all solid state secondary battery of Example 11 is of a bipolar type.
In the laminated member for an all-solid-state secondary battery of Example 11, the thickness of each layer is the same as that of Example 8.

<Example 12>
In Example 11, after the fourth current collector layer precursor coating film was formed, the slurry for forming a negative electrode active material layer was coated with the above-mentioned slurry in a state where the residual solvent amount of the fourth current collector layer precursor coating film was 5% by mass. It was applied by an applicator so as to have a basis weight of 20 mg / cm ² to form a coating film (fourth negative electrode active material layer precursor coating film) on the fourth current collector layer precursor coating film.
With the residual solvent amount of the fourth negative electrode active material layer precursor coating film being 5% by mass, the solid electrolyte layer forming slurry was applied on the fourth negative electrode active material layer precursor coating film by the above-mentioned applicator with a basis weight of 8 mg / cm ² . To form a coating film (fourth solid electrolyte layer precursor coating film) on the fourth negative electrode active material layer precursor coating film.
With the residual solvent amount of the fourth solid electrolyte layer precursor coating film being 5% by mass, the slurry for forming a positive electrode active material layer was applied onto the fourth solid electrolyte layer precursor coating film by the above-mentioned applicator with a basis weight of 30 mg / cm ^2. Thus, a coating film (fourth positive electrode active material layer precursor coating film) was formed on the fourth solid electrolyte layer precursor coating film.
With the residual solvent amount of the fourth positive electrode active material layer precursor coating film being 5% by mass, a slurry for forming a current collector layer was applied onto the fourth positive electrode active material layer precursor coating film by the above-mentioned applicator with a basis weight of 10 mg / cm ² . And a coating film (fifth current collector layer precursor coating film) was formed on the fourth positive electrode active material layer precursor coating film.
The laminate thus obtained by wet-on-wet coating is heated at 120 ° C. for 2 hours to remove the dispersion medium, and has a laminated structure in which four laminating units are stacked (an embodiment of the laminated structure (c) described above). A laminated member for an all solid state secondary battery of Example 5 was obtained. The laminated member for an all solid state secondary battery of Example 12 is of a bipolar type.
In the laminated member for an all solid state secondary battery of Example 12, the thickness of each layer is the same as that of Example 8.

<Example 13>
Example 1 was repeated in the same manner as in Example 1 except that 6.0 g of carbon black used in the slurry for forming the current collector layer was replaced with 6.0 g of copper powder (manufactured by Hayashi Junyaku Kogyo Co., Ltd.). Thus, thirteen laminated members for an all-solid secondary battery were obtained.

<Comparative Example 1>
In the same manner as in Example 1, except that a copper foil (thickness: 20 μm) was adhered to the negative electrode active material layer precursor coating film instead of forming the second current collector layer precursor coating film on the anode active material layer precursor coating film. Thus, a laminated member for an all-solid secondary battery of Comparative Example 1 was obtained.

<Comparative Example 2>
Two laminated members for an all-solid-state secondary battery of Comparative Example 1 were prepared, and an aluminum foil of a second laminated member was stacked on a copper foil of a first laminated member. A laminated member for a secondary battery was obtained.

<Comparative Example 3>
Three laminated members for an all solid state secondary battery of Comparative Example 1 were prepared, and a second laminated member was placed on the copper foil of the first laminated member so that the aluminum foil side of the second laminated member was in contact with the laminated member. The third stacked member was stacked on the copper foil of the second stacked member such that the aluminum foil side of the third stacked member was in contact with the stacked member, and the stacked member for an all solid state secondary battery of Comparative Example 3 was obtained. Obtained.

<Comparative Example 4>
Four laminated members for an all-solid-state secondary battery of Comparative Example 1 were prepared, and a second laminated member was placed on the copper foil of the first laminated member so that the aluminum foil side of the second laminated member was in contact. Stack the third laminated member on the copper foil of the second laminated member so that the aluminum foil side of the third laminated member is in contact with the copper foil of the third laminated member. The fourth laminated member was stacked so that the aluminum foil side of the first laminated member was in contact with the first laminated member to obtain a laminated member for an all-solid secondary battery of Comparative Example 4.

<Comparative Example 5>
In Example 1, application of the current collector layer forming slurry onto the negative electrode active material layer precursor coating film was performed by drying at 120 ° C. for 120 minutes after forming the negative electrode active material layer precursor coating film. A laminated member for an all-solid-state secondary battery of Comparative Example 5 was obtained in the same manner as in Example 1, except that the dispersion medium was removed from the film.

<Comparative Example 6>
In Example 3, application of the current collector layer forming slurry onto the negative electrode active material layer precursor coating film was performed by drying at 120 ° C. for 120 minutes after forming the negative electrode active material layer precursor coating film. After the dispersion medium is removed from the film, the application of the slurry for forming the current collector layer onto the second negative electrode active material layer precursor coating film is performed at 120 ° C. after the formation of the second negative electrode active material layer precursor coating film. A laminated member for an all-solid-state secondary battery of Comparative Example 6 was obtained in the same manner as in Example 3, except that drying was performed for 120 minutes to remove the dispersion medium from the second negative electrode active material layer precursor coating film. .

<Comparative Example 7>
Comparative Example 5 was prepared in the same manner as in Comparative Example 5, except that 6.0 g of copper powder (manufactured by Hayashi Junyaku Kogyo) was used instead of 6.0 g of carbon black used in the slurry for forming the current collector layer. Thus, a laminated member for an all-solid secondary battery No. 7 was obtained.

<Comparative Example 8>
In Comparative Example 5, all of Comparative Example 8 was performed in the same manner as in Example 1 except that 6.0 g of carbon black used for the slurry for forming the current collector layer was replaced with 6.0 g of stainless steel powder for sintering. A laminated member for a solid state secondary battery was obtained.

[Preparation of all solid state secondary battery]
The laminated member for an all solid state secondary battery obtained above was pressed at 50 MPa for 10 seconds. Then, it was cut out into a circle having a diameter of 15 mm. The cut sample was placed in a 2032 type coin case, pressurized at 600 MPa, and then the coin case was swaged to produce an all-solid secondary battery.

[Evaluation of battery performance]
The battery performance of the all solid state secondary battery was evaluated using a charge / discharge evaluation device “TOSCAT-3000” (trade name) manufactured by Toyo System Corporation. Specifically, the all-solid-state secondary battery was charged at a current value of 0.2 mA until the battery voltage reached 4.2 V, and then discharged at a current value of 2.0 mA until the battery voltage reached 3.0 V. The battery voltage 10 seconds after the start of discharging was read according to the following criteria, and evaluated by applying the following criteria. The higher the battery voltage 10 seconds after the start of discharging, the lower the resistance.
<Evaluation criteria>
AA: 4.10 V or more A: 4.05 V or more and less than 4.10 V B: 4.00 V or more and less than 4.05 V C: 3.90 V or more and less than 4.00 V D: Less than 3.90 V The results are shown in the table below.

As shown in the above table, when all the current collectors of the laminated member were formed of metal foil, the obtained all-solid secondary battery resulted in high battery resistance and poor performance (Comparative Examples 1 to 4). In addition, even when the current collector layer of the laminated member is formed of slurry, when the method of applying the current collector layer forming slurry is wet-on-dry coating, the battery resistance is still high and the performance is inferior. (Comparative Examples 5 to 8).
In contrast, when the current collector layer is formed wet-on-wet using the current collector layer forming slurry, the battery resistance can be sufficiently suppressed, and an all-solid secondary battery having excellent battery performance can be obtained. (Examples 1 to 13).

Although the present invention has been described in conjunction with its embodiments, we do not intend to limit our invention in any detail of the description unless otherwise specified, which is contrary to the spirit and scope of the invention as set forth in the appended claims. I believe that it should be interpreted broadly without.

This application claims the priority based on Japanese Patent Application No. 2018-173571 filed in Japan on September 18, 2018, which is hereby incorporated by reference. Capture as a part.

101, 102 Laminated member 1 for all solid state secondary battery Current collector layer (metal foil)
2 Positive electrode active material layer 3 Solid electrolyte layer 4 Negative electrode active material layer 5 Current collector layer A Stacking unit B Stacking unit 103 All solid state secondary battery 11 Negative current collector 12 Negative electrode active material layer 13 Solid electrolyte layer 14 Positive electrode active material layer 15 positive electrode current collector layer

Claims

A laminate including a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order, and a current collector layer disposed on each surface of the positive electrode active material layer and the negative electrode active material layer of the laminate. In the production of laminated members for solid state rechargeable batteries,
An all-solid-state method including forming a laminated structure of at least one active material layer of the positive electrode active material layer and the negative electrode active material layer and a current collector layer in contact with the active material layer by wet-on-wet coating. Method for producing laminated member for secondary battery.
The laminated member for an all-solid secondary battery includes a first current collector layer made of metal foil, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a second current collector layer. The structure in which the positive electrode active material layer, the solid electrolyte layer, the negative electrode active material layer, and the second current collector layer are formed in a laminated structure in this order comprises the metal foil. The method for producing a laminated member for an all-solid secondary battery according to claim 1, wherein the method is performed by simultaneous multilayer coating on the first current collector layer.
The laminated member for an all-solid secondary battery includes a first current collector layer made of a metal foil, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, and a second current collector layer. The negative electrode active material layer, the solid electrolyte layer, the positive electrode active material layer, and the second current collector layer are laminated in this order. The method for producing a laminated member for an all-solid secondary battery according to claim 1, wherein the method is performed by simultaneous multilayer coating on the first current collector layer.
The laminated member for an all-solid secondary battery is a laminate in which a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer are laminated in this order, and is in contact with the positive electrode active material layer or the negative electrode active material layer of the laminate. A stacked unit composed of a current collector layer arranged and arranged on a current collector layer made of metal foil, has a stacked structure in which a plurality of layers are stacked so that the current collector layers do not contact each other,
2. The production of the laminated member for an all-solid-state secondary battery according to claim 1, wherein the formation of the laminated structure in which the laminated units are stacked in a plurality of stages is performed by simultaneous multilayer coating on the current collector layer made of the metal foil. Method.
5. The method for producing a laminated member for an all-solid secondary battery according to claim 1, wherein the current collector layer formed by wet-on-wet coating contains a particulate binder.
The method for producing a laminated member for an all-solid secondary battery according to any one of claims 1 to 5, wherein the solid electrolyte constituting the solid electrolyte layer is a sulfide-based inorganic solid electrolyte.
The method for producing a laminated member for an all-solid secondary battery according to any one of claims 1 to 6, wherein a laminated member for an all-solid secondary battery is obtained, and the laminated member for an all-solid secondary battery is used. A method for producing an all-solid secondary battery, which obtains a solid secondary battery.