JPWO2020059550A1 - Manufacturing method of laminated member for all-solid-state secondary battery and manufacturing method of all-solid-state secondary battery - Google Patents

Abstract

All including 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 arranged on each surface of the positive electrode active material layer and the negative electrode active material layer of this laminate. In the manufacture of laminated members for solid secondary batteries
An all-solid rechargeable battery 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. A method for manufacturing a laminated member for a secondary battery, and a method for manufacturing an all-solid secondary battery using this manufacturing method.

Description

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

A lithium ion secondary battery is a storage battery that has a negative electrode, a positive electrode, and an electrolyte sandwiched between the negative electrode and the positive electrode, and can be charged and discharged by reciprocating lithium ions between the two electrodes. Conventionally, an organic electrolyte has been used as an electrolyte in a lithium ion secondary battery. However, the organic electrolytic solution is liable to leak, and there is a risk of short-circuiting and ignition inside the battery due to overcharging or overdischarging, and further improvement in safety and reliability is required.
Under such circumstances, an all-solid-state secondary battery using an inorganic solid electrolyte instead of the organic electrolyte has attracted attention. In an all-solid-state secondary battery, the negative electrode, electrolyte, and positive electrode are all made of solid, which can greatly improve the safety and reliability of batteries using organic electrolytes, and can also extend the life of the battery. It is said that Further, the all-solid-state secondary battery can have a laminated structure in which electrodes and electrolytes are directly arranged side by side and arranged in series. Therefore, it is possible to increase the energy density as compared with a secondary battery using an organic electrolytic solution, and it is expected to be applied to various electronic devices, electric vehicles, large storage batteries, and the like.

The basic layer structure of an all-solid-state secondary battery is a laminated structure consisting of 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 structure 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 a solid electrolyte layer. Similarly, the negative electrode is generally in the form of a laminated negative electrode current collector layer made of metal foil and a negative electrode active material layer, and 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 made of solid particles, and the current collector layer and the active material layer The electron conductivity between them may not be sufficient, or peeling may occur between the current collector layer and the active material layer.
As a technique for dealing with this problem, Patent Document 1 is coated with all of the functional layers of the first current collector layer, the first active material layer, the electrolyte layer, the second active material layer, and the second current collector layer. It is described that it is formed by. 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 improved, and a battery having good characteristics can be manufactured.

An all-solid secondary battery is a collection 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, and a collection arranged in contact with the positive electrode active material layer or the negative electrode active material layer of the laminate. It is known that a laminated structure composed of an electric body layer is regarded as one unit, and this unit is stacked in a plurality of stages on a current collecting body such as a metal foil so that the current collecting body layers do not come into contact with each other. ing. The output of the battery can be increased by adopting such a plurality of units configuration. Monopolar type and bipolar type are known as multi-unit configurations. In the monopolar type, positive electrode active material layers are arranged on both sides of the positive electrode current collector layer, and negative electrode current collectors are arranged on both sides of the negative electrode current collector layer. That is, the active material layers arranged 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.

Japanese Unexamined Patent Publication No. 2012-64487

The present inventors have repeatedly studied the techniques described in Patent Document 1 for the purpose of further improving the battery performance. As a result, as described in Patent Document 1, a coating liquid (slurry) containing a constituent material of the current collector layer was prepared, and this coating liquid was applied onto the active material layer to form a current collector layer. Even in this case, the adhesion between the current collector layer and the active material layer is improved by the low resistance during charging and discharging (improvement of electron conductivity between the current collector layer and the active material layer during charging and discharging), which has been required in recent years. It has not been possible to raise the level to a sufficiently satisfactory level, and it has become clear that there are restrictions on improving battery performance.

The present invention provides a method for manufacturing a laminated member for an all-solid-state secondary battery, which can be used as a component of an all-solid-state secondary battery to obtain an all-solid-state secondary battery in which resistance during charging and discharging is sufficiently suppressed. The task is to do. 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 in which resistance during charging and discharging is sufficiently suppressed.

The present inventors have made extensive 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 arranged on each surface of the positive electrode active material layer and the negative electrode active material layer of this laminate. In the production of the laminated member for the all-solid secondary battery including the above, the laminated structure of the positive electrode active material layer or the negative electrode active material layer and the current collector layer in contact with the positive electrode active material layer is formed by wet-on-wet coating, and the obtained all-solid material is formed. It has been found that by applying a laminated member for a secondary battery to an all-solid secondary battery, an all-solid secondary battery with sufficiently suppressed resistance can be provided. Based on this finding, the present invention has been further studied and completed.

That is, the above problem was solved by the following means.
[1]
All including 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 arranged on each surface of the positive electrode active material layer and the negative electrode active material layer of this laminate. In the manufacture of laminated members for solid secondary batteries
An all-solid-state battery 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. A method for manufacturing a laminated member for a next 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. It is a 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 laminated in this order. The method for manufacturing a laminated member for an all-solid secondary battery according to [1], which is carried out by simultaneous layer coating on the current collector layer.
[3]
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. It is a 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 laminated in this order. The method for manufacturing a laminated member for an all-solid secondary battery according to [1], which is carried out by simultaneous layer coating on the current collector layer.
[4]
The laminated member for an all-solid secondary battery is in contact with 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 positive electrode active material layer or a negative electrode active material layer of the laminated body. It has a laminated structure in which a laminated unit composed of the current collector layers arranged therein is stacked in a plurality of stages on a current collector layer made of a metal foil so that the current collector layers do not come into contact with each other.
Manufacture of the laminated member for an all-solid-state secondary battery according to [1], wherein a laminated structure in which the above-mentioned laminated units are stacked in a plurality of stages is formed by simultaneous layering on a current collector layer made of the above-mentioned metal foil. Method.
[5]
The method for producing a laminated member for an all-solid-state 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]
All-solid-state secondary battery laminated members are obtained by the method for manufacturing all-solid-state secondary battery laminated members according to any one of [1] to [6], and all the all-solid-state secondary battery laminated members are used. A method for manufacturing an all-solid-state secondary battery to obtain a solid-state secondary battery.

In the description of the present invention, the numerical range represented by using "~" means a range including the numerical values before and after "~" as the lower limit value and the upper limit value.

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

FIG. 1 is a vertical cross-sectional view schematically showing a layer structure of a monopolar type all-solid-state secondary battery. FIG. 2 is a vertical cross-sectional view schematically showing the layer structure of the bipolar type all-solid-state secondary battery. FIG. 3 is a vertical cross-sectional view schematically showing the basic configuration of an all-solid-state secondary battery.

Preferred embodiments will be described for the method for manufacturing the laminated member for the all-solid-state secondary battery and the method for manufacturing the all-solid-state secondary battery of the present invention. It is not limited.

[Manufacturing method of laminated members for all-solid-state secondary batteries]
The method for manufacturing a laminated member for an all-solid-state secondary battery of the present invention (hereinafter, also referred to as "the manufacturing 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 positive electrode active material layer and a current collector layer arranged on each surface of the negative electrode active material layer of this laminated body (hereinafter, also referred to as "laminated member of the present invention". ) Is a way to get.
In the production method of the present invention, 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 formed by wet-on-wet coating. Including doing.
In the present invention, "wet-on-wet coating" means a coating method in which a plurality of coating films are repeatedly coated without being dried (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 the coating method by sequential coating, even if the formed coating film is dried to a certain extent, when another coating film is formed on the coating film with a residual solvent amount of 5% by mass or more, "wet" is used. "On-wet application". In addition, simultaneous multi-layer coating is also performed in which a plurality of coating liquids (slurries) for forming different layers are simultaneously supplied to the coating apparatus from the stage of the coating process, and the plurality of laminated coating liquids are simultaneously coated on the substrate. It is a form of "wet-on-wet application".

As a preferable laminated structure that can be adopted by the laminated member of the present invention, the following laminated structures (a) to (c) can be mentioned.

(A) A laminated structure having 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 in this order.
(B) A laminated structure having 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 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 arranged in contact with the positive electrode active material layer or the negative electrode active material layer of this laminate. A laminated structure in which multiple laminated units composed of the above are stacked on a current collector layer made of metal foil so that the current collector layers do not come into contact with each other.

In the above (a), the first current collector layer made of a metal foil serves as a base material when forming a coating film. For example, when the positive electrode active material layer / solid electrolyte layer / negative electrode active material layer / second current collector layer is formed by simultaneous layer coating, simultaneous layer coating is performed on the first current collector layer made of metal foil. Be told. This also applies to (b). The laminated structure of the above (a) and (b) corresponds to the layer structure of the all-solid-state secondary battery shown in FIG. 3 described later.

In the above (c), in one laminated unit, the current collector layer constituting the laminated unit is a positive electrode active material of 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. It is arranged in contact with either the layer or 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 arranged.
That is, the stacking of a plurality of stages of the laminated units is such that the current collectors of the laminated units do not contact each other, and the active material layer of another laminated unit is arranged on the surface of the current collector layer of one laminated unit. To do.
As a laminated structure in which a plurality of laminated units are stacked, there are a monopolar type laminated structure and a bipolar type laminated structure. In the monopolar type laminated structure, in the form in which the laminated units are stacked, the same type of active material layer is arranged on both sides of the current collector layer constituting the laminated unit. That is, when the positive electrode active material layer is arranged on one side of one current collector layer, the positive electrode active material layer is also arranged on the other side. Similarly, when the negative electrode active material layer is arranged on one side of one current collector layer, the negative electrode active material layer is also arranged on the other side.
FIG. 1 shows an example of a monopolar type laminated structure. This monopolar type laminated structure (laminated member 101) is composed of two types of laminated units. That is, a unit 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, and the current collector layer 5 is provided in contact with the positive electrode active material layer 2 (FIG. 1). The current collector layer 5 was provided in contact with the negative electrode active material layer 4 of the laminate in which B), 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 stages are stacked on the current collector layer (metal foil) 1 so that the current collector layers do not come into contact with each other (FIG. 1 is a structure in which three layers are stacked). As a result, a monopolar type laminated structure can be obtained.
On the other hand, in the bipolar type laminated structure, in the form in which the laminated units are stacked, different types of active material layers are arranged on both sides of the current collector layer constituting the laminated unit. That is, when the positive electrode active material layer is arranged on one side of one current collector layer, the negative electrode active material layer is arranged on the other side.
An example of the bipolar type laminated structure is shown in FIG. This bipolar type laminated structure (laminated member 102) is composed of one type of laminated unit. That is, a unit 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, and the current collector layer 5 is provided in contact with the negative electrode active material layer 4 (FIG. 2). The inside A) is a bipolar type by forming 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 come into contact with each other (FIG. 2 shows a structure in which three layers are stacked). Can be laminated. Further, the collector layers form a unit in which the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer are laminated in this order, and the current collector layer is provided in contact with the positive electrode active material layer. A bipolar type laminated structure can also be obtained by forming a structure in which a plurality of stages are stacked on the current collector layer (metal foil) so as not to come into contact with each other.

In the present invention, the expression "laminated unit" is used for convenience in order to specify the layer structure of the laminated structure. That is, the "laminated structure in which a plurality of laminated units are stacked" is not intended to be a form in which a plurality of laminated units are manufactured in advance and the plurality of laminated units are actually stacked. On the current collector layer made of metal foil, the slurry for forming each layer of the positive electrode active material layer, the solid electrolyte layer, the negative electrode active material layer and the current collector layer is repeatedly applied layer by layer, or the positive electrode active material layer. , The solid electrolyte layer, the negative electrode active material layer, and the current collector layer are applied in multiple layers at the same time so that the order is repeated. If the laminated structure is the same as the whole, it is included in the laminated structure of (c) above.

In the manufacturing method of the present invention, when the laminated member having the laminated structure of the above (a) is formed, 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 wet. Perform by on-wet application. For example, a slurry containing the constituent material of the negative electrode active material layer is applied and coated on the solid electrolyte of the three-layer structure of the first current collector layer / positive electrode active material layer / solid electrolyte layer made of metal foil. A film is formed, and a slurry containing a 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 coating, it is dried to obtain a laminated member having the above-mentioned laminated structure (a). On the solid electrolyte layer, a slurry containing a constituent material of the negative electrode active material layer and a slurry containing a constituent material of the second current collector layer can be simultaneously coated.
Further, 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, a slurry containing a constituent material of the solid electrolyte layer and a negative electrode active material layer are configured. The slurry containing the material and the slurry containing the constituent material of the second current collector layer can be sequentially or simultaneously applied in multiple layers by wet-on-wet application.
Further, on the first current collector layer made of metal foil, 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 slurry containing a constituent material of the negative electrode active material layer , The slurry containing the constituent material of the second current collector layer can be sequentially or simultaneously applied in multiple layers by wet-on-wet application.
Considering mass production, 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 configuration of a negative electrode active material layer are formed on a first current collector layer made of a metal foil. It is preferable to simultaneously coat the slurry containing the material and the slurry containing the constituent material of the second current collector layer in multiple layers.

In the manufacturing method of the present invention, when the laminated member having the laminated structure of the above (b) is formed, 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 wet. Perform by on-wet application. For example, a slurry containing the constituent material of the positive electrode active material layer is applied and coated on the solid electrolyte of the three-layer structure of the first current collector layer / negative electrode active material layer / solid electrolyte layer made of metal foil. A film is formed, and a slurry containing a 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 coating, it is dried to obtain a laminated member having the above-mentioned laminated structure (b). A slurry containing a constituent material of the positive electrode active material layer and a slurry containing a constituent material of the second current collector layer can be simultaneously coated on the above solid electrolyte.
Further, on the negative electrode active material layer of the two-layer structure of the first current collector layer / negative electrode active material layer made of metal foil, a slurry containing a constituent material of the solid electrolyte layer and a positive electrode active material layer are configured. The slurry containing the material and the slurry containing the constituent material of the second current collector layer can be sequentially or simultaneously applied in multiple layers by wet-on-wet application.
Further, on the first current collector layer made of metal foil, a slurry containing a constituent material of the negative electrode active material layer, a slurry containing a constituent material of the solid electrolyte layer, and a slurry containing a constituent material of the positive electrode active material layer , The slurry containing the constituent material of the second current collector layer can be sequentially or simultaneously applied in multiple layers by wet-on-wet application.
Considering mass production, a slurry containing a constituent material of the negative electrode active material layer, a slurry containing a constituent material of the solid electrolyte layer, and a configuration of the positive electrode active material layer on the first current collector layer made of metal foil. It is preferable to simultaneously coat the slurry containing the material and the slurry containing the constituent material of the second current collector layer in multiple layers.

In the manufacturing method of the present invention, when the laminated member having the laminated structure of the above (c) is formed, 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 in contact with the active material layer. The laminated structure with the electric body layer is formed by wet-on-wet coating. More preferably, each layer constituting each laminated unit is formed by coating a slurry containing a constituent material of each layer sequentially or simultaneously on a current collector layer made of a metal foil, and then drying to form the laminated unit. Form a laminated structure in which is stacked in a plurality of stages.
In consideration of mass production, each layer constituting each laminated unit is formed by simultaneously coating a slurry containing the constituent materials of each layer on a current collector layer made of a metal foil, and then drying to form the laminated unit. It is preferable to form a laminated structure having a structure in which a plurality of stages are stacked. In this case, the laminated structure can be formed in one step, and the production efficiency of the monopolar type or bipolar type laminated member can be greatly improved.

The slurry itself for forming each of the above layers can be prepared by a conventional method. Specifically, at least the constituent materials of each layer described later and the dispersion medium can be mixed and prepared. This mixing can be performed using various mixers. For example, ball mills, bead mills, planetary mixers, blade mixers, roll mills, kneaders, disc mills 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 film thickness, dispersibility and the like.

Examples of the dispersion medium used in the slurry include an alcohol compound solvent, an ether compound solvent, an amide compound solvent, an amino compound solvent, a ketone compound solvent, an ester compound solvent, an aromatic compound solvent, an aliphatic compound solvent, and a nitrile compound solvent. ..
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 can be mentioned.

Examples of the ether compound solvent include alkylene glycol alkyl ether (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, and di. Propropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, diethylene glycol monobutyl ether, diethylene glycol dibutyl ether, etc.), dialkyl ether (dimethyl ether, diethyl ether, dibutyl ether, etc.), tetrahydrofuran, and dioxane (1,2-, 1,3- and 1). , 4-Including each isomer).

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, and N. Included are-methylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpropanamide, and hexamethylphosphoric triamide.

Examples of the amino compound solvent include triethylamine and tributylamine.

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 butyl, isobutyl isobutyrate, pentyl butyrate, methyl valerate, ethyl valerate, propyl valerate, butyl valerate, methyl caproate, ethyl caproate, propyl caproate, butyl caproate and the like.

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

Aliphatic compound solvents include, for example, hexane, heptane, cyclohexane, methylcyclohexane, ethylcyclohexane, decalin, octane, pentane, cyclopentane, and cyclooctane.

Examples of the nitrile compound solvent include acetonitrile, propyronitrile, and butyronitrile.

The coating method for forming the film of each of the above slurries is not particularly limited and can be appropriately selected. For example, in the case of sequential multi-layer coating, it can be carried out 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.
Further, the simultaneous multi-layer coating itself can be performed by a conventional method. For example, Japanese Patent Application Laid-Open No. 2005-271283 and Japanese Patent Application Laid-Open No. 2006-247967 can be referred to. Further, for example, simultaneous layer coating can be performed using a die (multilayer dedicated gieser) described in Japanese Patent Application Laid-Open No. 2018-12283.
The drying temperature of the coating film after 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. The drying temperature is preferably 300 ° C. or lower, more preferably 250 ° C. or lower, and even more preferably 200 ° C. or lower.

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

<Solid electrolyte layer>
The solid electrolyte layer constituting the laminated member of the present invention can be formed of the usual constituent materials used for the solid electrolyte layer in the all-solid secondary battery. In the present invention, the solid electrolyte layer preferably has an inorganic solid electrolyte having ionic conductivity of a metal belonging to Group 1 or Group 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 by applying, for example, a solid electrolyte composition (slurry) containing the above-mentioned inorganic solid electrolyte, a binder, and the above-mentioned dispersion medium. it can. The content of each component of the solid electrolyte composition can be appropriately adjusted according to the intended purpose. For example, the content of the inorganic solid electrolyte in the solid content of the solid electrolyte composition is preferably 50% by mass or more, more preferably 70% by mass or more, further 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 capable of transferring ions inside the solid electrolyte. Since it does not contain organic substances as the main ionic conductive material, it is an organic solid electrolyte (polymer electrolyte typified by polyethylene oxide (PEO), organic typified by lithium bis (trifluoromethanesulfonyl) imide (LiTFSI), etc. It is clearly distinguished from electrolyte salts). Further, since the inorganic solid electrolyte is a solid in a steady state, it is usually not dissociated or liberated into cations and anions. _{In this respect, it is also clearly distinguished from an electrolyte or an inorganic electrolyte salt (LiPF 6} , LiBF ₄ , LiFSI, LiCl, etc.) in which cations and anions are dissociated or liberated in the polymer. The inorganic solid electrolyte is not particularly limited as long as it has the ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and is generally not electron conductive.

In the present invention, the inorganic solid electrolyte has ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table. As the inorganic solid electrolyte, a solid electrolyte material applicable to this type of product can be appropriately selected and used. Typical examples of the inorganic solid electrolytes are (i) sulfide-based inorganic solid electrolytes and (ii) oxide-based inorganic solid electrolytes, which are sulfides in terms of high ionic conductivity and ease of interparticle interface bonding. A based inorganic solid electrolyte is preferable.
When the all-solid-state secondary battery of the present invention is an all-solid-state 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), has ionic conductivity of a metal belonging to Group 1 or Group 2 of the Periodic Table, and has ionic conductivity. , A compound having electronic insulation is preferable. The sulfide-based inorganic solid electrolyte preferably contains at least Li, S and P as elements and has lithium ion conductivity, but other than Li, S and P may be used depending on the purpose or case. It may contain elements.

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).

_La1 M _b1 P _c1 S _d1 A _e1 equation (I)

In the formula, L represents an element selected from Li, Na and K, with Li being preferred. M represents an element selected from B, Zn, Sn, Si, Cu, Ga, Sb, Al and Ge. A represents an element selected from I, Br, Cl and F. a1 to e1 indicate the composition ratio of each element, and a1: b1: c1: d1: e1 satisfy 1 to 12:00 to 5: 1: 2 to 12:00 to 10. a1 is preferably 1 to 9, more preferably 1.5 to 7.5. b1 is preferably 0 to 3, more preferably 0 to 1. d1 is preferably 2.5 to 10 and more preferably 3.0 to 8.5. e1 is preferably 0 to 5, more preferably 0 to 3.

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

The sulfide-based inorganic solid electrolyte may be non-crystal (glass) or crystallized (glass-ceramic), or only a part thereof may be crystallized. For example, Li-PS-based glass containing Li, P and S, or Li-PS-based glass ceramics containing Li, P and S can be used.
Sulfide-based inorganic solid electrolytes include, for example, lithium sulfide (Li ₂ S), phosphorus sulfide (for example, diphosphorus pentasulfide (P ₂ S ₅ )), simple phosphorus, simple sulfur, sodium sulfide, hydrogen sulfide, and lithium halide (eg, lithium halide). It can be produced by the reaction of at least two or more raw materials in sulfides of LiI, LiBr, LiCl) and the element represented by M (for example, SiS ₂ , SnS, GeS _2).

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 It is 90:10, more preferably 68:32 to 78:22. By _{setting the ratio of Li 2} S and P ₂ S ₅ in this range, the lithium ion conductivity can be made high. Specifically, the lithium ion conductivity can be preferably 1 × 10 ^-4 S / cm or more, and more preferably 1 × 10 ^-3 S / cm or more. There is no particular upper limit, but it is practical that it is ^{1 × 10 -1 S / cm or less.}

As an example of a specific sulfide-based inorganic solid electrolyte, an example of combining raw materials is shown below. For _{example, Li 2 S-P 2 S} 5, Li 2 S-P 2 S 5 -LiCl, Li 2 S-P 2 S 5 -H 2 S, Li 2 S-P 2 S 5 -H 2 S-LiCl, Li ₂ S-LiI-P ₂ S ₅ , Li ₂ S-LiI-Li ₂ O-P ₂ S ₅ , Li ₂ S-LiBr-P ₂ S ₅ , Li ₂ S-Li ₂ O-P ₂ S ₅ , Li ₂ S-Li ₃ PO _4- P ₂ S ₅ , Li ₂ S-P ₂ S _5- P ₂ O ₅ , Li ₂ S-P ₂ S _5- SiS ₂ , Li ₂ S-P ₂ S _5- SiS _2- LiCl, Li ₂ S-P ₂ S _5- SnS, Li ₂ S-P ₂ S _5- Al ₂ S ₃ , Li ₂ S-GeS ₂ , Li ₂ S-GeS _2- ZnS, Li ₂ S-Ga ₂ S ₃ , Li ₂ S-GeS _2- Ga ₂ S ₃ , Li ₂ S-GeS _2- P ₂ S ₅ , Li ₂ S-GeS _2- Sb ₂ S ₅ , Li ₂ S-GeS _2- Al ₂ S ₃ , Li ₂ S-SiS ₂ , Li ₂ S-Al ₂ S ₃ , Li ₂ S-SiS _2- Al ₂ S ₃ , Li ₂ S-SiS _2- P ₂ S ₅ , Li ₂ S-SiS _2- P _{2 S 5 -LiI, Li 2 S} -SiS 2 -LiI, such as _{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 room temperature is 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 Group 2 of the Periodic Table, and has ionic conductivity. , A compound having an electron insulating property is 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 (M ^bb is at least one element of Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In, Sn, xb satisfies 5 ≦ xb ≦ 10, and yb is 1 ≦ yb. ≦ 4 was filled, zb satisfies 1 ≦ zb ≦ 4, mb satisfies 0 ≦ mb ≦ 2, nb satisfies _{5 ≦ nb ≦ 20.),} Li xc B yc M cc zc O nc (M cc is C, S, Al, Si, Ga, Ge, In, Sn are at least one element, xc satisfies 0 ≦ xc ≦ 5, yc satisfies 0 ≦ yc ≦ 1, and zc satisfies 0 ≦ zc ≦. met 1, nc satisfies _{0 ≦ nc ≦ 6.),} Li xd (Al, 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), the number of ^{_{Li (3-2xe) M ee xe D}} ee O (xe 0 to 0.1 ^{represents, M ee} is ^{.D ee} representing the divalent metal atom represent a combination of halogen atom or 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), LISION (Lithium superionic compound) ) Type crystal structure Li _3.5 Zn _0.25 GeO _{4 , La 0.55} Li _{0.35 TIO 3} having a perovskite type crystal structure, _{LiTi 2} P ₃ having a NASICON (Naturium superionic compound) type crystal structure O ₁₂ , Li _{1 + xh + yh} (Al, Ga) _xh (Ti, Ge) _2-xh Si _yh P _3-yh O ₁₂ (however, 0 ≦ xh ≦ 1, 0 ≦ yh ≦ 1), Li having a garnet-type crystal structure ₇ La ₃ Zr ₂ O ₁₂ (LLZ) and the like can be mentioned. Phosphorus compounds containing Li, P and O are also desirable. For example, lithium phosphate (Li ₃ PO ₄ ), LiPON in which a part of oxygen of lithium phosphate is replaced with nitrogen, LiPOD ¹ (D ¹ is Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr. , Nb, Mo, Ru, Ag, Ta, W, Pt, Au and the like (at least one selected from) and the like. Further, LiA ¹ ON (A ¹ is at least one selected from Si, B, Ge, Al, C, Ga and the like) and the like can also be preferably used.

The inorganic solid electrolyte is preferably particles. In this case, the particle size of the inorganic solid electrolyte is not particularly limited. From the viewpoint of ionic conductivity, processability and interface forming property, the particle size of the inorganic solid electrolyte is preferably 0.01 μm or more, more preferably 0.2 μm or more, still more preferably 0.3 μm or more. The particle size 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 the average particle size and can be determined as follows.
The inorganic solid electrolyte particles are diluted and adjusted by 1% by mass of a dispersion in a 20 mL sample bottle with water (heptane in the case of a water-unstable substance). The diluted dispersed sample is irradiated with 1 kHz ultrasonic waves for 10 minutes, and immediately after that, it is used for the test. Using this dispersion sample, data was captured 50 times using a measurement quartz cell at a temperature of 25 ° C. using a laser diffraction / scattering particle size distribution measuring device LA-920 (trade name, manufactured by HORIBA). Obtain the volume average particle size. For other detailed conditions, etc., 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 polymer compounds (polymers). The binder enhances the binding property between the inorganic solid electrolyte particles and contributes to the improvement of mechanical strength, ionic conductivity and the like. The organic polymer compound constituting the binder may contain a particulate compound or a non-particulate compound. From the viewpoint of further enhancing ionic conductivity, a particulate binder is preferable. The particulate binder has a primary particle size (volume average particle size) of preferably 10 to 1000 nm, more preferably 20 to 750 nm, further preferably 30 to 500 nm, and even more preferably 50 to 300 nm.

The binder can be composed of, for example, the organic polymer compounds described below.

-Fluororesin-
Examples of the fluororesin include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and a copolymer of polyvinylidene fluoride and hexafluoropropylene (PVdF-HFP).

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

-(Meta) acrylic resin-
Examples of the (meth) acrylic resin include various (meth) acrylic monomers, (meth) acrylamide monomers, and two or more copolymers of these monomers.
Further, a copolymer (copolymer) with other vinyl-based monomers is also preferably used. Examples thereof include 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 either a statistical copolymer or a periodic copolymer, and a random copolymer is preferable.

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

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, fluorine-containing resin, hydrocarbon-based thermoplastic resin, (meth) acrylic resin, polyurethane resin, polycarbonate resin and cellulose derivative resin are preferable, and the affinity with the inorganic solid electrolyte is good, and the resin itself A (meth) acrylic resin or a polyurethane resin is particularly preferable because it has good flexibility and can exhibit stronger binding property to solid particles.
Commercially available products can be used as the above-mentioned various resins. It can also be prepared by a conventional method.
The number average molecular weight of the polymer constituting the binder is preferably 1000 to 1000000, more preferably 1000 to 500000, from the viewpoint of improving the binding property between the 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, the lithium salt usually used for this kind of product is preferable, and there is no particular limitation. For example, the lithium salt described in paragraphs 0083-00885 of JP2015-088486 is preferable.
When the solid electrolyte-containing layer contains a lithium salt, the content of the lithium salt is preferably 0.1 part by mass or more, more preferably 5 parts by mass or more, based on 100 parts by mass of the inorganic solid electrolyte. The upper limit is preferably 50 parts by mass or less, more preferably 20 parts by mass or less.

(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 one that dissolves the above-mentioned lithium salt is preferable from the viewpoint of effectively improving the ionic conductivity. For example, a compound composed of a combination of the following cations and anions can be mentioned.

<Positive electrode active material layer, Negative electrode active material layer>
The positive electrode active material layer and the negative electrode active material layer constituting the laminated member of the present invention can be formed of ordinary constituent materials used in an all-solid-state 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 structure as the above-mentioned solid electrolyte layer except that they contain an active material.
That is, in the present invention, the positive electrode active material layer and the negative electrode active material layer are compositions in which the above-mentioned solid electrolyte composition contains the corresponding active material (positive electrode forming composition and negative electrode forming composition). Collectively, it is also referred to as an electrode forming composition), and this can be applied to a base material to form the electrode. The content of each component in the electrode-forming composition can be appropriately adjusted according to the intended 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, more preferably 30 to 90% by mass.

(Active material)
The shape of the active material is not particularly limited, but is preferably in the form of particles. Further, the particle size of the active material is not particularly limited as long as the above particle size ratio is satisfied. The particle size of the active material is preferably 0.1 μm or more, more preferably 1 μm or more, and 2 μm or more in terms of improving dispersibility, improving the contact area between solid particles, and reducing interfacial reactivity. Is even 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 the 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 particle size is measured by observation with a transmission electron microscope (TEM) after the active material is dried to dryness, if necessary.

-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-mentioned properties, and may be a transition metal oxide, an organic substance, an element that can be composited with Li such as sulfur, or a composite of sulfur and a metal.
Among them, as the positive electrode active material, a transition metal oxide having preferably used a transition metal oxide, a transition metal element ^{M a (Co, Ni, Fe} , Mn, 1 or more elements selected from Cu and V) the Things are more preferred. Further, the 1 (Ia) group elements of the transition metal oxide to elemental ^{M b} (Table metal periodic other than lithium, the elements of the 2 (IIa) group, Al, Ga, In, Ge , Sn, Pb, Elements such as Sb, Bi, Si, P or B) may be mixed. The mixing amount, 0~30mol% is preferred for the amount of the transition metal element ^{M a (100mol%).} It is more preferable that the mixture is synthesized by mixing so that the molar ratio of Li / Ma is 0.3 to 2.2.
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 phosphoric acid compound, and (MD). ) Lithium-containing transition metal halide phosphoric acid compound, (ME) lithium-containing transition metal silicic acid compound, and the like.

(MA) Specific examples of the transition metal oxide having a layered rock salt structure include LiCoO ₂ (lithium cobalt oxide [LCO]), LiNi ₂ O ₂ (lithium nickel oxide), LiNi _0.85 Co _0.10 Al _{0. 05} O ₂ (Lithium Nickel Cobalt Oxide [NCA]), LiNi _1/3 Co _1/3 Mn _1/3 O ₂ (Lithium Nickel Manganese Cobalt Oxide [NMC]) and LiNi _0.5 Mn _0.5 O ₂ ( Lithium manganese nickel oxide).
(MB) Specific examples of the transition metal oxide having a spinel _{structure, 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 can be mentioned.
Examples of the (MC) lithium-containing transition metal phosphate compound include olivine-type iron phosphate salts such as _{LiFePO 4} and Li ₃ Fe ₂ (PO ₄ ) ₃ , iron pyrophosphates such as _{LiFeP 2} O _{7 , and LiCoPO 4.} Examples thereof include cobalt phosphates of the above, and monoclinic panocycon-type vanadium phosphate salts such as Li ₃ V ₂ (PO ₄ ) _{3 (vanadium lithium 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 Fluorophosphate cobalts such as.
Examples of the (ME) lithium-containing transition metal silicic acid 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.

In order to obtain the desired particle size of the positive electrode active material, a normal crusher or classifier may be used. The positive electrode active material obtained by the firing method may be used after being washed with water, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent.

The positive electrode active material may be used alone or in combination of two or more.
When forming the positive electrode active material layer, the mass (mg) (grain amount) 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 appropriately determined 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, and is a carbonaceous material, a metal oxide such as tin oxide, a silicon oxide, a metal composite oxide, a lithium simple substance, a lithium alloy such as a lithium aluminum alloy, and the like. , Sn, Si, Al, In and other metals that can be alloyed with lithium. Of these, carbonaceous materials or lithium composite oxides are preferably used from the viewpoint of reliability. Further, as the metal composite oxide, it is preferable that lithium can be occluded and released. The material is not particularly limited, but it is preferable that the material contains titanium and / or lithium as a constituent component from the viewpoint of high current density charge / discharge characteristics.

The carbonaceous material used as the negative electrode active material is a material substantially composed of carbon. For example, various synthesis of 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 mentioned. Furthermore, various carbon fibers such as PAN-based carbon fibers, cellulose-based carbon fibers, pitch-based carbon fibers, vapor-grown carbon fibers, dehydrated PVA (polypoly alcohol) -based carbon fibers, lignin carbon fibers, graphitic carbon fibers, and activated carbon fibers. Kind, mesophase microspheres, graphite whisker, flat graphite and the like can also be mentioned.

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. Be done. Amorphous here means an X-ray diffraction method using CuKα rays, which has a broad scattering band having an apex in a region of 20 ° to 40 ° in 2θ value, and is a crystalline diffraction line. May have.

Among the compound group consisting of the amorphous oxide and the chalcogenide, the amorphous oxide of the metalloid element and the chalcogenide are more preferable, and the elements of the groups 13 (IIIB) to 15 (VB) of the periodic table, Al. , Ga, Si, Sn, Ge, Pb, Sb and Bi alone or a combination of two or more of them oxides, and chalcogenides are particularly preferred. 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 SnSi _{S 3} are preferably mentioned. 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]) has excellent rapid charge / discharge characteristics due to small volume fluctuations during storage and release of lithium ions, and electrode deterioration is suppressed and lithium ion secondary It is preferable in that the life of the battery can be improved.

In the present invention, it is also preferable to apply a Si-based negative electrode. In general, the Si negative electrode can occlude more Li ions than the carbon negative electrode (graphite, acetylene black, etc.). That is, the amount of Li ions occluded per unit mass increases. Therefore, the battery capacity can be increased. As a result, there is an advantage that the battery drive time can be lengthened.

An ordinary crusher or classifier is used to adjust the negative electrode active material to a predetermined particle size. For example, a mortar, a ball mill, a sand mill, a vibrating ball mill, a satellite ball mill, a planetary ball mill, a swirling airflow type jet mill, a sieve, and the like are preferably used. At the time of pulverization, wet pulverization in which water or an organic solvent such as methanol coexists can also be performed, if necessary. It is preferable to perform classification in order to obtain a desired particle size. The classification method is not particularly limited, and a sieve, a wind power classifier, or the like can be used as needed. Both dry and wet classifications can be used.

The chemical formula of the compound obtained by the above firing method can be calculated from the inductively coupled plasma (ICP) emission spectroscopic analysis method as a measuring method and the mass difference of the 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) (grain amount) 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 appropriately determined according to the designed battery capacity.

The surfaces of the positive electrode active material and the negative electrode active material may be surface-coated with another metal oxide. Further, the surface of the positive electrode active material or the particle surface of the negative electrode active material may be surface-treated with active light rays or an active gas (plasma or the like) 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 agent. The conductive auxiliary agent is not particularly limited, and those known as general conductive auxiliary agents can be used. For example, graphites such as natural graphite and artificial graphite, carbon blacks such as acetylene black, ketjen black and furnace black, amorphous carbon such as needle coke, vapor-grown carbon fibers or carbon nanotubes, which are electron conductive materials. It may be a carbon fiber such as graphene or fullerene, a metal powder such as copper or nickel, or a metal fiber, and a conductive polymer such as polyaniline, polypyrrole, polythiophene, polyacetylene, or polyphenylene derivative. You may use it.

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 even more preferably 20 to 200 μm, respectively, considering the dimensions of a general all-solid-state secondary battery. Further, each layer 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 plurality of layers. In the case of multiple layers, it is preferable that the thickness of the entire multiple layers is within the above preferable range.

In the laminated member of the present invention, the above-mentioned 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 a lithium metal powder, a lithium foil, a lithium vapor deposition film, and the like. The thickness of the lithium metal layer can be, for example, 1 to 500 μm regardless of the thickness of the negative electrode active material layer.

<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 metal foil. It is preferable that the slurry for forming each layer is sequentially or simultaneously applied on the metal foil.
When this metal foil is used as the positive electrode current collector layer, its constituent materials include aluminum, aluminum alloy, stainless steel, nickel and titanium. Further, a material obtained by treating the surface of aluminum or stainless steel with carbon, nickel, titanium or silver (a thin film formed) is also preferable. Among them, aluminum and aluminum alloys are more preferable.
When the metal foil is used as the negative electrode current collector layer, the constituent materials thereof include aluminum, copper, copper alloy, stainless steel, nickel and titanium. Further, it is also preferable that the surface of aluminum, copper, copper alloy or stainless steel is treated with carbon, nickel, titanium or silver. Among them, aluminum, copper, copper alloy and stainless steel are more preferable as the constituent materials of the negative electrode current collector layer.

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

When the laminated member of the present invention has, for example, the laminated structure of (a) and (b) above, as described above, the second current collector layer is a slurry containing a constituent material of the second current collector layer. Is formed using. This slurry can be in the form of containing the powder of the constituent material of the second current collector layer. In the laminated structure of (a) above, the second current collector layer is a negative electrode current collector layer, and powders (particles) such as aluminum, copper, copper alloy, stainless steel, nickel and titanium are used as the conductive material. The contained slurry can be applied to form a second current collector layer. Further, in the laminated structure of the above (b), the second current collector layer is a positive electrode active material layer, and a slurry containing powders such as aluminum, aluminum alloy, stainless steel, nickel and titanium as a conductive material is used. It can be used to form a second 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 coat and form the current collector layer using a slurry formed 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 made of the metal foil as the base material contain the constituent materials of the current collector layer. It is formed by wet-on-wet application using the slurry to be used. The constituent material of the current collector layer can be appropriately selected from the above-mentioned constituent materials in consideration of forms such as a monopolar type and a bipolar type.
The slurry for forming the current collector layer preferably contains a binder. The preferred form of the binder is the same as that of the binder described above. By including the binder, the binding property of the constituent materials of the current collector layer can be enhanced, the adhesion to the active material layer can be enhanced, and the resistance during charging and discharging of the battery can be suppressed to a lower level.
The content of the constituent material of the current collector layer in the slurry may be appropriately adjusted according to 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 7/1 to 20. It is more preferable to set it to 1/1.

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 even more preferably 2 to 200 μm.

In the production method of the present invention, it is preferable that the types of dispersion media 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.

[Manufacturing method of all-solid-state secondary battery]
The method for manufacturing an all-solid-state secondary battery of the present invention is a method of obtaining a laminated member of the present invention by the above-mentioned manufacturing method of the present invention and using the laminated member to obtain an all-solid-state secondary battery. To the method for manufacturing the all-solid-state secondary battery of the present invention, a normal manufacturing process for the all-solid-state secondary battery may be applied except that the laminated member of the present invention is used. The laminated member of the present invention operates as a secondary battery as it is, but usually, the laminated member of the present invention is housed in an appropriate housing (enclosed in a housing, housed in a coin case, etc.). An all-solid-state secondary battery is used under pressure.
The housing may be made of metal or resin (plastic). When a metallic material is used, for example, one made of aluminum alloy or stainless steel can be mentioned. It is preferable that the metallic housing is divided into a positive electrode side housing and a negative electrode side housing, 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 a short circuit.

<Initialization>
The all-solid-state secondary battery manufactured as described above is preferably initialized after manufacturing or before use. The initialization is not particularly limited, and can be performed, for example, by performing initial charging / discharging with the press pressure increased, and then releasing the pressure until the pressure reaches the general working pressure of the all-solid-state secondary battery.

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 showing this all-solid-state secondary battery, and the description of the housing and the like is omitted, and the laminated member of the present invention (corresponding to the laminated structure of (a) and (b) above). It shows the configuration. The all-solid-state secondary battery 103 has 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 when viewed from the negative electrode side. Each layer is in contact with each other and has an adjacent structure. By adopting such a structure, during charging, electrons (e ⁻ ) are supplied to the negative electrode side, and lithium ions (Li ⁺ ) are accumulated there. On the other hand, at the time of discharge, the 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 used as a model for the operating portion 16, and the light bulb is turned on by electric discharge.

The all-solid-state secondary battery obtained by the production method of the present invention can be applied to various uses. The application mode is not particularly limited, but for example, when mounted on an electronic device, a laptop 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, or a mobile phone. Examples include copying, mobile printers, headphone stereos, video movies, LCD TVs, handy cleaners, portable CDs, mini discs, electric shavers, transceivers, electronic notebooks, calculators, portable tape recorders, radios, backup power supplies, memory cards, etc. Other consumer products include automobiles (electric vehicles, etc.), electric vehicles, motors, lighting equipment, toys, game equipment, road conditioners, watches, strobes, cameras, medical equipment (pacemakers, hearing aids, shoulder massagers, etc.). .. Furthermore, it can be used for various munitions and space. It can also be combined with a solar cell.

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.

[Sulfide-based inorganic solid electrolyte (Li-PS-based glass) synthesis]
Sulfide-based inorganic solid electrolytes are described in T.I. Ohtomo, A.M. Hayashi, M. et al. Tassumisago, Y. et al. Tsuchida, S.A. Hama, K.K. Kawamoto, Journal of Power Sources, 233, (2013), pp231-235 and A.M. Hayashi, S.A. Hama, H. Morimoto, M.D. Tatsumi sago, T. et al. Minami, Chem. Lett. , (2001), pp872-873, was synthesized with reference to the non-patent documents.

Specifically, in a glove box under an argon atmosphere (dew point -70 ° C.), lithium sulfide (Li ₂ S, manufactured by Aldrich, purity> 99.98%) 2.42 kg, diphosphorus pentasulfide (P ₂ S). _5. Aldrich, purity> 99%) 3.90 kg was weighed, put into an agate mortar, and mixed for 5 minutes using an agate mortar. The molar ratios of _{Li 2} S and P ₂ S _{5 were Li 2} S: P ₂ S ₅ = 75: 25.
66 zirconia beads having a diameter of 5 mm were put into a 45 mL container made of zirconia (manufactured by Fritsch), and the entire mixture of lithium sulfide and diphosphorus pentasulfide was put into the container, and the container was sealed under an argon atmosphere. A container is set in a planetary ball mill P-7 (trade name) manufactured by Fritsch, and mechanical milling is performed at a temperature of 25 ° C. and a rotation speed of 510 rpm for 20 hours. Glass, also referred to as "LPS") 6.20 g was obtained.

[Preparation of slurry for forming solid electrolyte layer]
In a 45 mL container made of zirconia (manufactured by Fritsch), 130 zirconia beads having a diameter of 5 mm were put, 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 is 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 zirconia 45 mL container (manufactured 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. .. The container was set on 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. After that, 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 Co., Ltd.) as a conductive auxiliary agent were put into a container. Similarly, the container was set in the planetary ball mill P-7, and mixing was continued for 10 minutes at a temperature of 25 ° C. and a rotation speed of 100 rpm 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 were put into a zirconia 45 mL container (manufactured by Fritsch), and 2.8 g of LPS-based glass synthesized above, 0.2 g of SBS as a binder, and 12.3 g of heptane as a dispersion medium were put into the container. did. The container was set on 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. After that, 7.0 g of graphite was put into a container as an active material, the container was similarly set in a planetary ball mill P-7, and mixing was continued at a temperature of 25 ° C. and a rotation speed of 200 rpm for 15 minutes to prepare a slurry for forming a negative electrode active material layer. Prepared.

[Preparation of slurry for current collector layer formation]
180 zirconia beads having a diameter of 5 mm were put into a 45 mL container made of zirconia (manufactured by 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 were put. A container was set on 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.

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

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

<Example 3>
In Example 1, after the second collector layer precursor coating film was formed, the positive electrode active material layer forming slurry was prepared 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 grain size 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, a slurry for forming a solid electrolyte layer was applied onto the second positive electrode active material layer precursor coating film by the above applicator in an amount ^{of 8 mg / cm 2.} 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 residual solvent amount of the second solid electrolyte layer precursor coating film being 5% by mass, the slurry for forming the negative electrode active material layer was applied onto the second solid electrolyte layer precursor coating film with the above applicator to obtain a coating amount ^{of 20 mg / cm 2.} 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 on the second negative electrode active material layer precursor coating film with the above applicator at a scale ^{of 10 mg / cm 2.} It was applied in an amount to form a coating film (third current collector layer precursor coating film) on the second negative electrode active material layer precursor coating film.
The laminated body 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 two laminated units are stacked (one form of the above-mentioned laminated structure (c)). A laminated member for an all-solid-state secondary battery of Example 3 was obtained. The laminated member for an all-solid-state secondary battery of Example 3 is a bipolar type.
In the laminated member for the all-solid-state secondary battery of Example 3, the thickness of each layer is the same as that of Example 1.

<Example 4>
In Example 3, after the third collector layer precursor coating film was formed, the positive electrode active material layer forming slurry was prepared in a state where the residual solvent amount of the third current collector layer precursor coating film was 5% by mass. It was applied by an applicator so as to have a grain size of 30 mg / cm ² , and a coating film (third positive electrode active material layer precursor coating film) was formed 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, a slurry for forming a solid electrolyte layer was applied onto the third positive electrode active material layer precursor coating film by the above applicator in an amount ^{of 8 mg / cm 2.} A coating film (third solid electrolyte layer precursor coating film) was formed 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 slurry for forming the negative electrode active material layer was applied onto the third solid electrolyte layer precursor coating film with the above applicator to obtain a coating amount ^{of 20 mg / cm 2.} 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 slurry for forming a current collector layer was applied on the third negative electrode active material layer precursor coating film with the above applicator at a scale ^{of 10 mg / cm 2.} It was applied in an amount to form a coating film (fourth current collector layer precursor coating film) on the third negative electrode active material layer precursor coating film.
The laminated body 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 three laminated units are stacked (one form of the above-mentioned laminated structure (c)). A laminated member for an all-solid-state secondary battery of Example 4 was obtained. The laminated member for an all-solid-state secondary battery of Example 3 is a bipolar type.
In the laminated member for the 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 the fourth collector layer precursor coating film was formed, the positive electrode active material layer forming slurry was prepared 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 grain size of 30 mg / cm ² , and a coating film (fourth positive electrode active material layer precursor coating film) was formed on the fourth current collector layer precursor coating film.
With the residual solvent amount of the 4th positive electrode active material layer precursor coating film being 5% by mass, a slurry for forming a solid electrolyte layer was applied onto the 4th positive electrode active material layer precursor coating film by the above applicator in an amount ^{of 8 mg / cm 2.} A coating film (fourth solid electrolyte layer precursor coating film) was formed on the positive electrode active material layer precursor coating film.
With the residual solvent amount of the 4th solid electrolyte layer precursor coating film being 5% by mass, the slurry for forming the negative electrode active material layer was applied onto the 4th solid electrolyte layer precursor coating film with the above applicator to obtain a coating amount ^{of 20 mg / cm 2.} 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 4th negative electrode active material layer precursor coating film being 5% by mass, a slurry for forming a current collector layer was applied on the 4th negative electrode active material layer precursor coating film with the above applicator at a scale ^{of 10 mg / cm 2.} It was applied in an amount to form a coating film (fifth current collector layer precursor coating film) on the fourth negative electrode active material layer precursor coating film.
The laminated body 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 laminated units are stacked (one form of the above-mentioned laminated structure (c)). 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 a bipolar type.
In the laminated member for the all-solid-state secondary battery of Example 5, the thickness of each layer is the same as that of Example 1.

<Example 6>
In 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). , 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 used as an oxide-based inorganic solid electrolyte LLZ: Li ₇ La ₃ Zr ₂ O ₁₂ (lithium lanthanum dilconate with an average particle size of 5.0 μm, manufactured by Toyoshima Seisakusho Co., Ltd.).
An all-solid-state secondary battery laminated member of Example 8 was obtained in the same manner as in Example 1 except that the case was replaced with.

<Example 8>
20 mg / mg of the slurry for forming the negative electrode active material layer prepared above on a copper foil (negative electrode current collector, thickness 20 μm) with an applicator (trade name: SA-201 Baker type applicator, manufactured by Tester Sangyo Co., Ltd.). The ^{coating was applied so as to have a texture of cm 2} , and a coating film (negative electrode active material layer precursor coating film) was formed on the negative electrode current collector layer made of copper foil.
With the residual solvent amount of the negative electrode active material layer precursor coating film being 5% by mass, a slurry for forming a solid electrolyte layer was applied onto the negative electrode active material layer precursor coating film so as to have a coating amount ^{of 8 mg / cm 2 by the above applicator.} The coating was applied to form a coating film (solid electrolyte layer precursor coating film) on the negative 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 slurry for forming the positive electrode active material layer was applied onto the solid electrolyte layer precursor coating film by the above applicator so as to have a grain size ^{of 30 mg / cm 2.} Then, a coating film (positive electrode active material layer precursor coating film) was formed on the solid electrolyte layer precursor coating film.
With the residual solvent amount of the positive electrode active material layer precursor coating film being 5% by mass, a slurry for forming a current collector layer was applied onto the positive electrode active material layer precursor coating film so as to have a coating amount ^{of 10 mg / cm 2 by the above applicator.} A coating film (second current collector layer precursor coating film) was formed 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 the laminate member for the all-solid-state secondary battery of Example 8 having the laminate structure of (b) described above. It was.
In the laminated member for an all-solid-state secondary battery of Example 8, the thickness of each layer formed by coating is the same as that of Example 1.

<Example 9>
On a copper foil (negative electrode current collector, thickness 20 μm), 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 placed in this order. Simultaneous multi-layer coating was performed using a multi-layer dedicated Gieser so that the coating films could be 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 the laminate member for the all-solid-state secondary battery of Example 9 having the laminate structure of (b) described above. It was.
In the laminated member for an all-solid-state secondary battery 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 collector layer precursor coating film, the slurry for forming the negative electrode active material layer was prepared 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 grain size 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, a slurry for forming a solid electrolyte layer was applied onto the second negative electrode active material layer precursor coating film by the above applicator in an amount ^{of 8 mg / cm 2.} A coating film (second solid electrolyte layer precursor coating film) was formed 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 slurry for forming the positive electrode active material layer was applied onto the second solid electrolyte layer precursor coating film with the above applicator to obtain a coating amount ^{of 30 mg / cm 2.} 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 slurry for forming a current collector layer was applied on the second positive electrode active material layer precursor coating film with the above applicator at a scale ^{of 10 mg / cm 2.} It was applied in an amount to form a coating film (third current collector layer precursor coating film) on the second positive electrode active material layer precursor coating film.
The laminated body 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 two laminated units are stacked (one form of the above-mentioned 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 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 collector layer precursor coating film, the slurry for forming the negative electrode active material layer was prepared in a state where the residual solvent amount of the third current collector layer precursor coating film was 5% by mass. It was applied by an applicator so as to have a grain size of 20 mg / cm ² , and a coating film (third negative electrode active material layer precursor coating film) was formed on the third current collector 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 slurry for forming a solid electrolyte layer was applied onto the third negative electrode active material layer precursor coating film by the above applicator in an amount ^{of 8 mg / cm 2.} A coating film (third solid electrolyte layer precursor coating film) was formed on the third negative electrode active material layer precursor coating film.
With the residual solvent amount of the 3rd solid electrolyte layer precursor coating film being 5% by mass, the slurry for forming the positive electrode active material layer was applied onto the 3rd solid electrolyte layer precursor coating film with the above applicator to obtain a coating amount ^{of 30 mg / cm 2.} 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 slurry for forming a current collector layer was applied on the third positive electrode active material layer precursor coating film with the above applicator at a scale ^{of 10 mg / cm 2.} It was applied in an amount to form a coating film (fourth current collector layer precursor coating film) on the third positive electrode active material layer precursor coating film.
The laminated body 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 three laminated units are stacked (one form of the above-mentioned laminated structure (c)). A laminated member for an all-solid-state secondary battery of Example 11 was obtained. The laminated member for an all-solid-state secondary battery of Example 11 is a bipolar type.
In the laminated member for the 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 collector layer precursor coating film was formed, the slurry for forming the negative electrode active material layer was prepared 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 grain size of 20 mg / cm ² , and a coating film (fourth negative electrode active material layer precursor coating film) was formed on the fourth current collector layer precursor coating film.
With the residual solvent amount of the 4th negative electrode active material layer precursor coating film being 5% by mass, a slurry for forming a solid electrolyte layer was applied onto the 4th negative electrode active material layer precursor coating film by the above applicator in an amount ^{of 8 mg / cm 2.} A coating film (fourth solid electrolyte layer precursor coating film) was formed on the fourth negative electrode active material layer precursor coating film.
With the residual solvent amount of the 4th solid electrolyte layer precursor coating film being 5% by mass, the slurry for forming the positive electrode active material layer was applied onto the 4th solid electrolyte layer precursor coating film with the above applicator to obtain a coating amount ^{of 30 mg / cm 2.} 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 4th positive electrode active material layer precursor coating film being 5% by mass, a slurry for forming a current collector layer was applied on the 4th positive electrode active material layer precursor coating film with the above applicator at a scale ^{of 10 mg / cm 2.} It was applied in an amount to form a coating film (fifth current collector layer precursor coating film) on the fourth positive electrode active material layer precursor coating film.
The laminated body 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 laminated units are stacked (one form of the above-mentioned laminated structure (c)). 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 a bipolar type.
In the laminated member for the all-solid-state secondary battery of Example 12, the thickness of each layer is the same as that of Example 8.

<Example 13>
In Example 1, 6.0 g of carbon black used in the slurry for forming a current collector layer was replaced with 6.0 g of copper powder (manufactured by Hayashi Junyaku Kogyo Co., Ltd.), but the same as in Example 1 was carried out. Thirteen laminated members for all-solid-state secondary batteries were obtained.

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

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

<Comparative example 3>
Three laminated members for all-solid-state secondary batteries of Comparative Example 1 are prepared, and the second laminated member is placed on the copper foil of the first laminated member so that the aluminum foil side of the second laminated member is in contact with the copper foil. Stacking The third laminated member is stacked on the copper foil of the second laminated member so that the aluminum foil side of the third laminated member is in contact with each other, and the laminated member for the all-solid secondary battery of Comparative Example 3 is formed. Obtained.

<Comparative example 4>
Four laminated members for all-solid secondary batteries of Comparative Example 1 are prepared, and the second laminated member is placed on the copper foil of the first laminated member so that the aluminum foil side of the second laminated member is in contact with the copper foil. Stacking, stacking 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, and four on the copper foil of the third laminated member. The fourth laminated member was stacked so that the aluminum foil side of the laminated member of the eye was in contact with each other to obtain a laminated member for an all-solid secondary battery of Comparative Example 4.

<Comparative example 5>
In Example 1, the coating of the current collector layer forming slurry on the negative electrode active material layer precursor coating film is dried at 120 ° C. for 120 minutes after the negative electrode active material layer precursor coating film is formed, and the negative electrode active material layer precursor coating is applied. 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 membrane.

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

<Comparative Example 7>
In Comparative Example 5, 6.0 g of carbon black used for the slurry for forming the current collector layer was replaced with 6.0 g of copper powder (manufactured by Hayashi Junyaku Kogyo Co., Ltd.), but the same as in Comparative Example 5 in Comparative Example. 7 laminated members for all-solid-state secondary batteries were obtained.

<Comparative Example 8>
In Comparative Example 5, all of Comparative Example 8 was carried out 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 secondary battery was obtained.

[Manufacturing of all-solid-state secondary battery]
The laminated member for an all-solid-state secondary battery obtained above was pressurized at 50 MPa for 10 seconds. Then, it was cut into a circle having a diameter of 15 mm. The cut-out sample was placed in a 2032 type coin case, pressurized at 600 MPa, and then the coin case was crimped to prepare an all-solid-state 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 Systems Co., Ltd. Specifically, the all-solid-state secondary battery was charged with 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 discharge 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 discharge, the lower the resistance.
<Evaluation criteria>
AA: 4.10V or more A: 4.05V or more and less than 4.10V B: 4.00V or more and less than 4.05V C: 3.90V or more and less than 4.00V D: less than 3.90V The results are shown in the table below.

As shown in the above table, when the current collectors of the laminated members are all made of metal foil, the obtained all-solid-state secondary battery has high battery resistance and is inferior in performance (Comparative Examples 1 to 4). Further, even when the current collector layer of the laminated member is formed of slurry, if 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).
On the other hand, when the current collector layer is formed wet-on-wet using the slurry for forming the current collector layer, the battery resistance can be sufficiently suppressed and an all-solid-state secondary battery having excellent battery performance can be obtained. It was possible (Examples 1 to 13).

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

The present application claims priority based on Japanese Patent Application No. 2018-173571 filed in Japan on September 18, 2018, which is referred to herein and is described herein. Incorporate as a part.

101, 102 Laminated member for all-solid-state secondary battery 1 Current collector layer (metal leaf)
2 Positive electrode active material layer 3 Solid electrolyte layer 4 Negative electrode active material layer 5 Current collector layer A Laminated unit B Laminated unit 103 All-solid secondary battery 11 Negative electrode 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 (7)

All including 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 arranged on each surface of the positive electrode active material layer and the negative electrode active material layer of the laminate. In the manufacture of laminated members for solid secondary batteries
An all-solid-state battery 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. A method for manufacturing a laminated member for a next battery. 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 is laminated in this order, and the formation of a laminated structure of the positive electrode active material layer, the solid electrolyte layer, the negative electrode active material layer, and the second current collector layer is made of the metal foil. The method for manufacturing a laminated member for an all-solid secondary battery according to claim 1, which is performed by simultaneously applying multiple layers 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 structure is laminated in this order, and the formation of a laminated structure of the negative electrode active material layer, the solid electrolyte layer, the positive electrode active material layer, and the second current collector layer is made of the metal foil. The method for manufacturing a laminated member for an all-solid secondary battery according to claim 1, which is performed by simultaneously applying multiple layers on the first current collector layer. The laminated member for an all-solid secondary battery is in contact with 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 a positive electrode active material layer or a negative electrode active material layer of the laminated body. It has a laminated structure in which a laminated unit composed of the current collector layers arranged therein is stacked in a plurality of stages on a current collector layer made of a metal foil so that the current collector layers do not come into contact with each other.
The production of a laminated member for an all-solid-state secondary battery according to claim 1, wherein a laminated structure in which the laminated units are stacked in a plurality of stages is formed by simultaneous layer coating on a current collector layer made of the metal foil. Method. The method for producing a laminated member for an all-solid-state secondary battery according to any one of claims 1 to 4, 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. A laminated member for an all-solid-state secondary battery is obtained by the method for manufacturing a laminated member for an all-solid-state secondary battery according to any one of claims 1 to 6, and the laminated member for an all-solid-state secondary battery is used for all. A method for manufacturing an all-solid-state secondary battery to obtain a solid-state secondary battery.

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