JP6948382B2 - All-solid-state secondary battery and its manufacturing method, as well as solid-state electrolyte sheet for all-solid-state secondary battery and positive electrode active material sheet for all-solid-state secondary battery - Google Patents

Description

The present invention relates to an all-solid-state secondary battery and a method for manufacturing the same. The present invention also relates to a solid electrolyte sheet for an all-solid secondary battery and a positive electrode active material sheet for an all-solid 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 electrolyte is liable to leak, and there is a risk of short-circuiting and ignition inside the battery due to overcharging and overdischarging, and further improvement in reliability and safety is required.
Under such circumstances, the development of an all-solid secondary battery using a nonflammable inorganic solid electrolyte instead of the organic electrolyte is being promoted. 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 service life. It is said that it will be.

In a lithium ion secondary battery, electrons move from the positive electrode to the negative electrode during charging, and at the same time, lithium ions are released from lithium oxides and the like constituting the positive electrode, and these lithium ions reach the negative electrode through an electrolyte and reach the negative electrode. It is stored in. In this way, a part of the lithium ions stored in the negative electrode takes in electrons and precipitates as metallic lithium. When this metallic lithium precipitate grows like a dendrite due to repeated charging and discharging, it eventually reaches the positive electrode, causing an internal short circuit and failing to function as a secondary battery. The dendrite is very thin, and even in an all-solid-state secondary battery using a solid as an electrolyte, it can grow through cracks or pinholes formed in the solid electrolyte layer. Therefore, it is important to prevent the growth of dendrites even in the all-solid-state secondary battery in order to extend the life of the battery.
In order to deal with the problem of internal short circuit due to dendrite, Patent Document 1 describes a technique of excessively adding elemental sulfur to the solid electrolyte layer to prevent the growth of dendrite by elemental sulfur. In the technique described in Patent Document 1, a solid electrolyte layer is formed by using a mixture in which simple sulfur is uniformly dispersed in a solid electrolyte powder. Therefore, this solid electrolyte layer is made from a mixture of a single sulfur powder and a solid electrolyte powder. It is a form of

International Publication No. 2011/010552

The technique described in Patent Document 1 aims to prevent the growth of dendrites from the negative electrode to the positive electrode. However, as a result of repeated studies by the present inventor, the all-solid-state secondary battery is repeatedly charged and discharged, so that the active material is repeatedly expanded and contracted, and the dendrite gradually protrudes from the end of the battery element, so that the battery capacity is reduced. It has become clear that there are cases. Then, it has become clear that there is a concern that the protruding dendrite may short-circuit with the positive electrode and the battery exterior.
Further, in the present invention, when an all-solid-state battery is crushed and loaded to deform the battery exterior and cracks or the like occur in the battery exterior, moisture gradually evaporates from the ends of the negative electrode layer and the positive electrode layer to the inside. We have also come to pay attention to the fact that it can be mixed. When a sulfide-based electrolyte is used as the solid electrolyte, there is a concern that water reacts with the electrolyte to generate toxic hydrogen sulfide.

The present invention can prevent dendrites such as metallic lithium from gradually protruding from the electrode ends, suppress a decrease in battery capacity, and prevent short circuits due to contact between the dendrites and the positive electrode or the battery exterior. An object of the present invention is to provide a solid-state secondary battery and a method for producing the same. Further, according to the present invention, even when a crack or the like occurs in the battery exterior due to a crushing load applied to the all-solid-state battery, it is possible to effectively prevent the invasion of water and suppress the generation of _{hydrogen sulfide (H 2 S).} An object of the present invention is to provide an all-solid-state secondary battery capable of producing the same and a method for producing the same. Another object of the present invention is to provide a solid electrolyte sheet for an all-solid-state secondary battery and a positive electrode active material sheet for an all-solid-state secondary battery, which make it possible to obtain the above-mentioned all-solid-state secondary battery.

As a result of diligent studies in view of the above problems, the present inventor has determined that at least the battery end is a specific inorganic insulation to prevent the phenomenon that dendrites that are deposited and grow from the negative electrode due to repeated charging and discharging protrude from the battery end. It can be effectively blocked by coating with a coating. As a result, it has been found that a decrease in battery capacity can be suppressed and an internal short circuit can be sufficiently suppressed. Further, it was conceived that the coating on the end portion of the battery can prevent the invasion of water into the electrolyte even when a crack or the like occurs in the battery exterior. It was found that the generation of hydrogen sulfide can be suppressed. The present invention has been further studied based on these findings and has been completed.

That is, the above problem was solved by the following means.
[1]
An all-solid-state secondary battery having a battery element member,
The battery element member has at least a negative electrode current collector, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector.
An inorganic insulating coating that covers at least the end of the battery element member and has a Young's modulus of 1 GPa or more at 25 ° C. is arranged at the end of the battery element member.
The inorganic insulating coating comprises inorganic insulating particles and a melt-solidified body of an insulating inorganic material that is solid at 100 ° C. and melts in a temperature range of 200 ° C. or lower.
The inorganic insulating coating contains an organic binder.
All-solid-state secondary battery.
[2]
An all-solid-state secondary battery having a battery element member,
The battery element member has at least a negative electrode current collector, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector.
An inorganic insulating coating that covers at least the end of the battery element member and has a Young's modulus of 1 GPa or more at 25 ° C. is arranged at the end of the battery element member.
The inorganic insulating coating comprises inorganic insulating particles and a melt-solidified body of an insulating inorganic material that is solid at 100 ° C. and melts in a temperature range of 200 ° C. or lower.
50 to 90% by mass content of the inorganic insulating particles of the inorganic insulating coating material in is,
An all-solid-state secondary battery in which the inorganic insulating particles constituting the inorganic insulating coating are the following (a), (b) or (c) :
(A) Inorganic insulating particles selected from aluminum oxide, zirconium oxide, silicon oxide, zeolite, cubic boron nitride, hexagonal boron nitride, and cerium oxide;
(B) Inorganic insulating particles that do not melt at 250 ° C;
(C) Inorganic insulating particles that are not melt-solidified bodies .
[3]
The all-solid-state secondary battery according to [1] or [2], which has a battery exterior in which the battery element member is inserted therein.
[4]
The all-solid-state secondary battery according to any one of [1] to [3], wherein the inorganic insulating particles are aluminum oxide having a volume average particle diameter of 1 μm or less.
[5]
The all-solid-state secondary battery according to any one of [1] to [4], wherein the insulating inorganic material contains sulfur and / or modified sulfur.
[6]
The all-solid-state secondary battery according to any one of [1] to [5], wherein the inorganic insulating coating prevents the growth of metallic lithium that grows from the negative end portion during charging and discharging.
[7]
A step of arranging a battery element member including at least a negative electrode current collector, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector inside the battery exterior.
A step of arranging inorganic insulating particles, an insulating inorganic material that is solid at 100 ° C. and melts in a temperature range of 200 ° C. or lower, and an organic binder at the end of the battery element member in the space inside the battery exterior.
The whole according to [1] , which includes a step of heating the battery outer body in a temperature range of 200 ° C. or lower to melt and solidify the insulating inorganic material to cover the end portion of the battery element member. A method for manufacturing a solid-state secondary battery.
[8]
A step of arranging a battery element member including at least a negative electrode current collector, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector inside the battery exterior.
A step of arranging inorganic insulating particles and an insulating inorganic material that is solid at 100 ° C. and melts in a temperature range of 200 ° C. or lower at the end of the battery element member in the space inside the battery exterior.
In 200 ° C. below the temperature range by heating the battery exterior body, the insulating inorganic material is melted solidified seen including a step of coating the end portion of the battery element member,
The inorganic insulating particles are the following (a) or (b) or (c'):
(A) Inorganic insulating particles selected from aluminum oxide, zirconium oxide, silicon oxide, zeolite, cubic boron nitride, hexagonal boron nitride, and cerium oxide;
(B) Inorganic insulating particles that do not melt at 250 ° C;
(C') Inorganic insulating particles that do not melt in the step of coating the end portion of the battery element member;
The content of the inorganic insulating particles in the inorganic insulating coating formed by the step of coating the end portion of the battery element member is 50 to 90% by mass.
The method for manufacturing an all-solid-state secondary battery according to [2].
[9]
The solid electrolyte sheet used for the all-solid-state secondary battery according to [1].
It has a solid electrolyte layer and an inorganic insulating coating that covers the ends of the solid electrolyte layer.
The inorganic insulating coating is composed of inorganic insulating particles, a melt-solidified body of an insulating inorganic material that is solid at 100 ° C. and melts in a temperature range of 200 ° C. or lower, and an organic binder, and has a Young ratio of 1 GPa at 25 ° C. The above is the solid electrolyte sheet for all-solid secondary batteries.
[10]
The solid electrolyte sheet used in the all-solid-state secondary battery according to [2].
It has a solid electrolyte layer and an inorganic insulating coating that covers the ends of the solid electrolyte layer.
The inorganic insulating coating is composed of inorganic insulating particles and a melt-solidified body of an insulating inorganic material that is solid at 100 ° C. and melts in a temperature range of 200 ° C. or lower, and has a Young's modulus of 1 GPa or more at 25 ° C. ,
50 to 90% by mass content of the inorganic insulating particles of the inorganic insulating coating material in is,
A solid electrolyte sheet for an all-solid secondary battery , wherein the inorganic insulating particles constituting the inorganic insulating coating are the following (a), (b) or (c) :
(A) Inorganic insulating particles selected from aluminum oxide, zirconium oxide, silicon oxide, zeolite, cubic boron nitride, hexagonal boron nitride, and cerium oxide;
(B) Inorganic insulating particles that do not melt at 250 ° C;
(C) Inorganic insulating particles that are not melt-solidified bodies .
[11]
The solid electrolyte sheet for an all-solid secondary battery according to [9] or [10], wherein the insulating inorganic material contains sulfur and / or modified sulfur.
[12]
The solid electrolyte sheet for an all-solid secondary battery according to any one of [9] to [11], wherein the inorganic insulating particles are aluminum oxide.
[13]
The positive electrode active material sheet used in the all-solid-state secondary battery according to [1].
It has a positive electrode active material layer and an inorganic insulating coating that covers both ends of the positive electrode active material layer.
The inorganic insulating coating is composed of inorganic insulating particles, a melt-solidified body of an insulating inorganic material that is solid at 100 ° C. and melts in a temperature range of 200 ° C. or lower, and an organic binder, and has a Young ratio of 1 GPa at 25 ° C. The above is the positive electrode active material sheet for all-solid secondary batteries.
[14]
The positive electrode active material sheet used in the all-solid-state secondary battery according to [2].
It has a positive electrode active material layer and an inorganic insulating coating that covers both ends of the positive electrode active material layer.
The inorganic insulating coating is composed of inorganic insulating particles and a melt-solidified body of an insulating inorganic material that is solid at 100 ° C. and melts in a temperature range of 200 ° C. or lower, and has a Young's modulus of 1 GPa or more at 25 ° C.
50 to 90% by mass content of the inorganic insulating particles of the inorganic insulating coating material in is,
Positive electrode active material sheet for all-solid-state secondary battery in which the inorganic insulating particles constituting the inorganic insulating coating are the following (a), (b) or (c) :
(A) Inorganic insulating particles selected from aluminum oxide, zirconium oxide, silicon oxide, zeolite, cubic boron nitride, hexagonal boron nitride, and cerium oxide;
(B) Inorganic insulating particles that do not melt at 250 ° C;
(C) Inorganic insulating particles that are not melt-solidified bodies .
[15]
The positive electrode active material sheet for an all-solid-state secondary battery according to [13] or [14], wherein the insulating inorganic material contains sulfur and / or modified sulfur.
[16]
The positive electrode active material sheet for an all-solid-state secondary battery according to any one of [13] to [15], wherein the inorganic insulating particles are aluminum oxide.

In 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.

The all-solid-state secondary battery of the present invention can effectively prevent the dendrite from protruding from the end of the battery element member during charging and discharging, and can suppress a decrease in battery capacity, and the dendrite and the positive electrode or the battery exterior body. It is possible to prevent a short circuit due to contact with. Furthermore joined by crushing weight all solid state secondary battery, even when a crack or the like occurs in the battery, it is possible to suppress the occurrence of hydrogen sulfide (H 2 _S).
Further, according to the method for manufacturing an all-solid-state secondary battery of the present invention, the dendrite can be effectively prevented from protruding from the end of the battery element member during charging to suppress a decrease in battery capacity, and the dendrite and the positive electrode or the battery exterior can be suppressed. It is possible to obtain an all-solid-state secondary battery that prevents a short circuit with the body. Furthermore joined by crushing weight all solid state secondary battery, even when a crack or the like occurs in the battery, it is possible to obtain an all-solid secondary battery that suppresses generation of hydrogen sulfide (H 2 _S).
Further, the solid electrolyte sheet for an all-solid-state secondary battery and the positive electrode active material sheet for an all-solid-state secondary battery of the present invention can be suitably used as a member (layer) of the all-solid-state secondary battery of the present invention.

The above and other features and advantages of the present invention will become more apparent from the description below and the accompanying drawings.

It is a vertical cross-sectional view which shows typically the basic structure of a general all-solid-state secondary battery. It is a vertical sectional view which shows typically the cylindrical all-solid-state secondary battery which concerns on a preferable embodiment of this invention, and is the enlarged sectional view of part A in FIG.

In the all-solid-state secondary battery of the present invention, the end portion of the battery element member is coated with an inorganic insulating coating, and the inorganic insulating coating effectively prevents the growth of dendrites that tend to protrude from the end portion of the battery element member. can do. In the present invention, "insulation" means having an electron insulating property, that is, a property of not allowing electrons to pass through. Further, in the present invention, when referring to "insulation", "insulation" or "electron insulation" ^{, it is preferable that the material has an electric conductivity of 10-9} S (Siemens) / cm or less at a measurement temperature of 25 ° C.
Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS. 1 and 2.

[All-solid-state secondary battery]
FIG. 1 shows the basic configuration of a general all-solid-state secondary battery. As shown in FIG. 1, the all-solid-state secondary battery 10 of the present embodiment has a negative electrode current collector 1, a negative electrode active material layer 2, a solid electrolyte layer 3, a positive electrode active material layer 4, and a positive electrode current collector when viewed from the negative electrode side. The body 5 has a structure in which the bodies 5 are laminated in this order. Adjacent layers in each layer are in direct contact with each other.
With the above structure, during charging, electrons (e ⁻ ) are supplied to the negative electrode side, and at the same time, the alkali metal or alkaline earth metal constituting the positive electrode active material is ionized. The ionized ions pass (conduct) through (conduct) the solid electrolyte layer 3 and move, and are accumulated in the negative electrode. For example, in a lithium ion secondary battery, lithium ions (Li ⁺ ) are accumulated in the negative electrode.
At the time of discharge, the above-mentioned alkali metal ion or alkaline earth metal ion accumulated in the negative electrode is returned to the positive electrode side, and electrons are supplied to the operating portion 6. In the illustrated example, a light bulb is used for the operating portion 6, and the light bulb is turned on by electric discharge.

Further, it is also preferable that the all-solid-state secondary battery of the present invention has a form in which the solid electrolyte layer 3 and the negative electrode current collector 1 are in direct contact with each other without having the negative electrode active material layer 2. In this form of all-solid-state secondary battery, a phenomenon is utilized in which a part of alkali metal ions or alkaline earth metal ions accumulated in the negative electrode during charging is combined with electrons and deposited as a metal on the surface of the negative electrode current collector. That is, in this form of the all-solid-state secondary battery, the metal deposited on the surface of the negative electrode functions as the negative electrode active material layer. For example, metallic lithium is said to have a theoretical capacity 10 times or more that of graphite, which is widely used as a negative electrode active material. Therefore, by depositing metallic lithium on the negative electrode and pressing the solid electrolyte layer against the precipitated metallic lithium, the metallic lithium layer can be formed on the surface of the current collector, resulting in high capacity and high energy density. It is said that it will be possible to realize the secondary battery of.
Further, in the all-solid-state secondary battery in which the negative electrode active material layer is removed, the thickness of the battery becomes thin, so that when the battery is wound in a roll shape, cracks in the solid electrolyte layer occur. There is also an advantage that it becomes possible to further suppress. Moreover, since the number of turns can be increased, the battery capacity can be increased.
In the present invention, the all-solid-state secondary battery having no negative electrode active material layer means that the negative electrode active material layer is not formed in the layer forming step in battery manufacturing. Then, as described above, the negative electrode active material layer is formed between the solid electrolyte layer and the negative electrode current collector by charging.

As shown in FIG. 2, the cylindrical all-solid-state secondary battery 30 realizes the layer structure shown in FIG. 1 in a cylindrical form. All-solid secondary battery 30 of the cylindrical type, in which power generating elements as a basic unit a layer structure shown in FIG. 1 are arranged in layers around the axis 22, the battery element member 21 by the laminate Is configured. That is, the battery element member 21 has at least a negative electrode current collector 21d, a solid electrolyte layer 21a, a positive electrode active material layer 21c, and a positive electrode current collector 21b. In the form shown in FIG. 2, the power generation element in which the negative electrode current collector 21d, the negative electrode active material layer 21e, the solid electrolyte layer 21a, the positive electrode active material layer 21c, and the positive electrode current collector 21b are laminated in this order is multi-layered. It is an electrode. In the cylindrical all-solid-state secondary battery 30, the two power generation elements in contact with each other share one current collector. That is, the negative electrode active material layer is provided on both sides of one current collector, and the positive electrode active material layer is provided on both sides of one current collector.
Further, the cylindrical all-solid-state secondary battery 30 may include a battery cover 23 as a battery exterior, if necessary.
Inside the battery cover 23, an inorganic insulating coating 24 having a Young's modulus of 1 GPa or more at 25 ° C., which covers at least the end portion of the battery element member 21, is arranged.
Further, the positive electrode current collector 21b of the battery element member 21 is connected to the battery positive electrode via the positive electrode tab 25 that is electrically connected, and the negative electrode current collector 21d of the battery element member 21 is electrically connected to the negative electrode tab 27. It is connected to the battery negative electrode 28 via.
By forming the laminated structure shown in FIG. 2, it is possible to increase the battery capacity.

In the all-solid-state secondary battery of the present invention, the thicknesses of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer are not particularly limited. Considering the dimensions of a general battery, the thickness of each layer is preferably 10 to 1000 μm, more preferably 20 μm or more and less than 500 μm.

In the present invention, the positive electrode active material layer and the negative electrode active material layer may be collectively referred to as an electrode layer. 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. To indicate either the positive electrode active material and the negative electrode active material, or both, they may be simply referred to as an active material or an electrode active material. The solid electrolyte layer usually does not contain a positive electrode active material and / or a negative electrode active material. The inorganic solid electrolyte constituting the solid electrolyte layer, or the combination of the inorganic solid electrolyte constituting the solid electrolyte layer and the active material is referred to as an inorganic solid electrolyte material.

(Inorganic insulation coating)
The inorganic insulating coating has inorganic insulating particles and an insulating inorganic material. The insulating inorganic material is an inorganic material having electronic insulating properties and having physical properties of being solid at 100 ° C. (that is, having a melting point exceeding 100 ° C.) and thermally melting in a temperature range of 200 ° C. or lower. "Thermal melting in the temperature range of 200 ° C. or lower" means that the thermal melting is performed in the temperature range of 200 ° C. or lower under 1 atm.
By using this insulating inorganic material, it is possible to easily heat the insulating inorganic material to a temperature at which it melts. By this heating, the molten insulating inorganic material spreads so as to cover the end portion of the battery element member. At the same time, the molten insulating inorganic material can be moved to the gap in the battery element member by the capillary phenomenon. After that, by cooling and solidifying the insulating inorganic material, it is possible to create a state in which the electronic insulating material is covered with substantially no gap along the shape of the end portion of the battery element member.
That is, in the all-solid-state secondary battery of the present invention, the inorganic insulating coating was formed by using a heat-melted solidified product of an insulating inorganic material that is in a solid state at 100 ° C. and heat-melts in a temperature range of 200 ° C. or lower. It is a thing.

In the present invention, the inorganic insulating coating is preferably made of a material that is harder than dendrite in the solid state in order to prevent the growth of dendrite. Therefore, in the present invention, the Young's modulus of the inorganic insulating coating is 1 GPa or more, preferably 4 to 400 GPa.
Examples of the insulating inorganic material constituting the inorganic insulating coating include sulfur and / or modified sulfur, iodine, and a mixture of iodine and sulfur, and sulfur and / or modified sulfur can be preferably used. .. Sulfur that can be used as an insulating inorganic material means elemental sulfur itself.
The modified sulfur is obtained by kneading sulfur and a modifier. For example, pure sulfur and an olefin polymer as a modifying additive can be kneaded to obtain modified sulfur in which a part of sulfur is modified into a sulfur polymer. The modified sulfur may contain an organic polymer, but in the present invention, the "modified sulfur" is included in the inorganic material. The presence of sulfur or modified sulfur in the inorganic insulating coating can more effectively block dendrites (alkali metals or alkaline earth metals) that have grown on the inorganic insulating coating.

Further, when the dendrite and sulfur come into contact with each other, the dendrite and sulfur react with each other. For example, the dendrites and the sulfur of the metal lithium is in contact, 2Li + _S → Li 2 S reaction occurs, the growth of dendrite in the inorganic insulating coating material stops. By this reaction, the reaction product also coexists in the inorganic insulating coating. Since this reaction product is an electron-insulating compound that is harder than the dendrite metal, it can prevent the growth of dendrites. That is, it is also preferable that the inorganic insulating coating contains a compound containing an alkali metal and / or a compound containing an alkaline earth metal generated by the above reaction. By taking such a form, the volume of the inorganic insulating coating is expanded, and the effect of closing the gap between the particles in the inorganic insulating coating or the slight gap between the inorganic insulating coating and the battery element member can be expected. Therefore, the end portion of the battery element member can be reliably covered with the inorganic insulating coating.
The content of the insulating inorganic material in the inorganic insulating coating is preferably 5 to 50% by mass, more preferably 10 to 50% by mass, still more preferably 10 to 20% by mass.

The inorganic insulating coating may contain an organic binder. By containing an organic binder, it is possible to enhance the binding property between particles and to form a more cohesive layer structure, which is preferable.

(Organic binder)
Examples of the organic binder include organic polymers. For example, an organic binder made of the resin described below is preferably used.

Examples of the fluororesin include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and a copolymer of polyvinylidene fluoride and hexafluoropropylene (PVdF-HFP).
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.
Examples of the acrylic resin include various (meth) acrylic monomers, (meth) acrylamide monomers, and copolymers of the monomers constituting these resins (preferably copolymers of acrylic acid and methyl acrylate). Be done.
Further, a copolymer (copolymer) with other vinyl-based monomers is also preferably used. For example, a copolymer of methyl (meth) acrylate and styrene, a polymer of methyl (meth) acrylate and acrylonitrile, and a polymer of butyl (meth) acrylate, acrylonitrile and styrene can be mentioned. In the present specification, the copolymer may be either a statistical copolymer or a periodic copolymer, and a block copolymer is preferable.
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.
These may be used individually by 1 type, or may be used in combination of 2 or more type.

As the organic binder, the above-mentioned resin is selected in order to suppress peeling from the current collector and improve the cycle life by binding the solid interface, which exhibits strong binding property. That is, it is preferably at least one selected from the group consisting of acrylic resins, polyurethane resins, polyurea resins, polyimide resins, fluororesins and hydrocarbon-based thermoplastic resins.

The organic binder preferably has a polar group in order to enhance the wettability and adsorptivity to the particle surface. The polar group is preferably a monovalent group containing a hetero atom, for example, a monovalent group containing a structure in which a hydrogen atom is bonded to any one of an oxygen atom, a nitrogen atom and a sulfur atom, and specific examples thereof include a carboxy group. Examples include a hydroxy group, an amino group, a phosphoric acid group and a sulfo group.

The average particle size of the organic binder is usually preferably 10 nm to 30 μm, and more preferably nanoparticles of 10 to 1000 nm.

The weight average molecular weight (Mw) of the organic binder is preferably 10,000 or more, more preferably 20,000 or more, and even more preferably 30,000 or more. The upper limit is preferably 1,000,000 or less, more preferably 200,000 or less, still more preferably 100,000 or less.
When the inorganic insulating coating contains an organic binder, the content of the organic binder in the inorganic insulating coating is preferably 0.5 to 6% by mass, more preferably 1 to 3% by mass.

In the present invention, the inorganic insulating coating preferably contains inorganic insulating particles different from the insulating inorganic material in addition to the insulating inorganic material. These inorganic insulating particles also have an action of inhibiting the growth of dendrites. Examples of the inorganic insulating particles include aluminum oxide, zirconium oxide, silicon oxide, zeolite, cubic boron nitride, hexagonal boron nitride, and cerium oxide. The inorganic insulating particles are usually fine particles, and the volume average particle diameter thereof is preferably 1 μm or less, more preferably 700 nm or less. By allowing these materials to exist in the inorganic insulating coating, the thermal melt easily permeates into the gaps of the inorganic insulating coating due to the capillary phenomenon, and it is possible to obtain a state with less gaps and high dendrite resistance.
The content of the inorganic insulating particles in the inorganic insulating coating is preferably 50 to 90% by mass, more preferably 70 to 85% by mass.

(Solid electrolyte layer)
The solid electrolyte layer of the present invention contains an inorganic solid electrolyte material. The inorganic solid electrolyte material constituting the solid electrolyte layer is an inorganic solid electrolyte or a mixture of the inorganic solid electrolyte and the active material, and usually consists of the inorganic solid electrolyte. Preferred forms of the inorganic solid electrolyte will be described below. The active material will be described later.

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 (polyelectrolyte represented by polyethylene oxide (PEO), organic such as lithium bis (trifluoromethanesulfonyl) imide (LiTFSI)). 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 inorganic electrolyte salts (LiPF 6} , LiBF ₄ , LiFSI, LiCl, etc.) in which cations and anions are dissociated or liberated in the electrolytic solution or 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 one that does not have electron conductivity.

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. As the inorganic solid electrolyte, (i) a sulfide-based inorganic solid electrolyte and / or (ii) an oxide-based inorganic solid electrolyte are generally used.

(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 electrons. Those having insulating properties are 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.
For example, a lithium ion conductive inorganic solid electrolyte satisfying the composition represented by the following formula (I) can be mentioned.

_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. Further, a1 is preferably 1 to 9, and more preferably 1.5 to 7.5. b1 is preferably 0 to 3. d1 is further preferably 2.5 to 10 and more preferably 3.0 to 8.5. e1 is further preferably 0 to 5, more preferably 0 to 3.

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

The sulfide-based inorganic solid electrolyte may be amorphous (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 the sulfides of the elements represented by LiI, LiBr, LiCl) and M above (for example, SiS ₂ , SnS, GeS _2).

The ratio of _{Li 2} S to P ₂ S _{5 in} Li-PS-based glass and Li-PS-based glass ceramics is the molar ratio of _{Li 2} S: P ₂ S _{5, preferably 60:40 to} 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, a combination example of raw materials is shown below. For _{example, Li 2 S-P 2 S} 5, Li 2 S-P 2 S 5 -LiCl, Li 2 S-P 2 S 5 -H 2 S, Li 2 S-P 2 S 5 -H 2 S-LiCl, Examples thereof include Li ₂ S-LiI-P ₂ S ₅ , Li ₂ S-LiI-Li ₂ O-P ₂ S ₅ , and Li ₂ S-LiBr-P ₂ S _5. In addition, 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 can be mentioned. Furthermore _{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, Examples thereof include Li ₂ S-GeS _{2- Sb 2} S ₅ and Li ₂ S-GeS _2- Al ₂ S _3. Furthermore, 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- LiI, Li ₂ S-SiS Examples thereof include _{2- LiI, Li 2} S-SiS _{2 -Li 4} SiO ₄ , Li ₂ S-SiS _{2 -Li 3} PO ₄ , Li ₁₀ GeP ₂ S ₁₂ . 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 any of a mechanical milling method, a solution method and a melt quenching method. This is because these methods can be processed at room temperature and can simplify the manufacturing process.

(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 Li _xa La _ya TiO ₃ [xa = 0.3 to 0.7, ya = 0.3 to 0.7] (LLT). Further, Li _{xb Layb} Zr _zb M ^bb _{mb Onb} (M ^bb is at least one element selected from Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In, Sn and the like. Xb is 5 ≦ xb ≦ 10, yb is 1 ≦ yb ≦ 4, zb is 1 ≦ zb ≦ 4, mb is 0 ≦ mb ≦ 2, and nb is 5 ≦ nb ≦ 20). Further, Li _{xc Byc} M ^cc _{zc Onc} (M ^cc is at least one element selected from C, S, Al, Si, Ga, Ge, In, Sn and the like, and xc is 0 ≦ xc ≦. 5. yc satisfies 0 ≦ yc ≦ 1, zc satisfies 0 ≦ zc ≦ 1, and nc satisfies 0 ≦ nc ≦ 6, and xc + yc + zc + nc ≠ 0). _{Furthermore, Li xd (Al, Ga)} yd (Ti, Ge) zd Si ad P md O nd (1 ≦ xd ≦ 3,0 ≦ yd ≦ 1,0 ≦ zd ≦ 2,0 ≦ ad ≦ 1,1 ≦ md ≦ 7, and ^{_{3 ≦ nd ≦ 13), Li}} (3-2xe) M ee xe D ee O (xe represents a number of 0 to ^{0.1, M ee} represents a divalent metal ^{atom, D ee} Represents a halogen atom or a combination of two or more kinds of halogen atoms.). Furthermore, Li _xf Si _{yf Ozf} (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), Li 3.5} Zn _0.25 GeO ₄ having a LISION (Lithium super ionic controller) type crystal structure, _{La 0.55} Li ₀ having a perovskite type crystal structure _{.35 TiO 3, NASICON (Natrium super} ionic conductor) type LiTi having a crystalline structure _{2 P 3 O 12, Li 1} + xh + yh (Al, Ga) xh (Ti, Ge) 2-xh Si yh P 3-yh O 12 ( provided that , 0 ≦ xh ≦ 1, 0 ≦ yh ≦ 1), Li ₇ La ₃ Zr ₂ O ₁₂ (LLZ) having a garnet-type crystal structure and the like. 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 particle size (volume average particle size) of the inorganic solid electrolyte is not particularly limited, but is preferably 0.01 μm or more, and more preferably 0.1 μm or more. The upper limit is preferably 100 μm or less, and more preferably 50 μm or less. The average particle size of the inorganic solid electrolyte particles is measured by the following procedure. 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 laser diffraction / scattering particle size distribution measuring device LA-920 (manufactured by HORIBA) at a temperature of 25 ° C. using a measuring quartz cell, and the volume average particles were used. Get the diameter. For other detailed conditions and the like, refer to the description of JISZ8828: 2013 "Particle size analysis-Dynamic light scattering method" as necessary. Five samples are prepared for each level and the average value is adopted.

(Positive electrode active material layer)
The positive electrode active material layer 4 contains the above-mentioned inorganic solid electrolyte and the positive electrode active material.
A preferable form of the positive electrode active material will be described.

-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 The thing is more preferable. 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 can be mentioned.

(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 Aluminate [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 Li ₃ V ₂ (PO ₄ ) ₃ (lithium vanadium phosphate) and other monoclinic pachicon-type vanadium phosphate salts.
(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, LMO, NCA or NMC is more preferable.

The shape of the positive electrode active material is not particularly limited, but is preferably in the form of particles. The volume average particle size (sphere-equivalent average particle size) of the positive electrode active material is not particularly limited. For example, it can be 0.1 to 50 μm. In order to make the positive electrode active material have a predetermined particle size, 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 volume average particle size (sphere-equivalent average particle size) of the positive electrode active material particles can be measured using a laser diffraction / scattering type particle size distribution measuring device LA-920 (trade name, manufactured by HORIBA).

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.

The content of the positive electrode active material in the positive electrode active material layer is not particularly limited, and is preferably 10 to 95% by mass, more preferably 30 to 90% by mass, further preferably 50 to 85% by mass, and 55 to 80% by mass. Is particularly preferable.

(Negative electrode active material layer)
The negative electrode active material layer 2 contains the above-mentioned inorganic solid electrolyte and the negative electrode active material. As described above, it is also preferable that the all-solid-state secondary battery of the present invention has a form in which the negative electrode active material layer is not formed in advance.
A preferable form of the negative electrode active material will be described.

-Negative electrode active material-
The negative electrode active material is preferably one that can reversibly store and release lithium ions. The material is not particularly limited as long as it has the above-mentioned properties. The materials include carbonaceous materials, metal oxides such as tin oxide, silicon oxide, metal composite oxides, lithium alloys such as lithium simplex and lithium-aluminum alloys, and lithium alloys such as Sn, Si, Al and In. Examples include metal that can be formed. 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 and 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, glassy carbon fibers, and activated carbon fibers. Kind can be mentioned. Further, mesophase microspheres, graphite whiskers, 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. The term "amorphous" as used herein means that in an X-ray diffraction method using CuKα rays, a diffraction angle 2θ has a broad scattering zone having an apex in a region of 20 ° to 40 °, and is crystalline diffraction. It may have a line.

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. In particular, one species selected from the elements of Groups 13 (IIIA) to 15 (VA) of the Periodic Table, Al, Ga, Si, Sn, Ge, Pb, Sb and Bi, or a combination of two or more thereof. Oxides consisting of, as well as chalcogenides are preferred. Specific examples of preferable amorphous oxides and chalcogenides include 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} . 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 This is preferable in that the battery life 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.

The shape of the negative electrode active material is not particularly limited, but is preferably in the form of particles. The particle size (volume average particle size) of the negative electrode active material is preferably 0.1 to 60 μm. A normal crusher or classifier is used to obtain 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 volume average particle size of the negative electrode active material particles can be measured by the same method as the above-mentioned method for measuring the volume average particle size of the positive electrode active material.

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 content of the negative electrode active material in the solid electrolyte composition is not particularly limited, and is preferably 10 to 80% by mass, more preferably 20 to 80% by mass, based on 100% by mass of the solid content.

The surface of the electrode containing the positive electrode active material or the negative electrode active material may be surface-treated with sulfur or phosphorus. Further, the particle surface of the positive electrode active material or 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.

In the all-solid-state secondary battery of the present invention, the solid electrolyte layer, the positive electrode active material layer and the negative electrode active material layer include a lithium salt, a conductive auxiliary agent, a binder (preferably an organic binder that can be contained in the above-mentioned inorganic insulating coating), and the like. It is also preferable that a dispersant or the like is contained.

[Current collector (metal leaf)]
The positive electrode current collector 5 and the negative electrode current collector 1 are preferably electron conductors.
In the present invention, either or both of the positive electrode current collector and the negative electrode current collector may be collectively referred to as a current collector.
As a material for forming the positive electrode current collector, in addition to aluminum, aluminum alloy, stainless steel, nickel and titanium, the surface of aluminum or stainless steel is treated with carbon, nickel, titanium or silver (a thin film is formed). ) Is preferable. Among them, aluminum and aluminum alloys are more preferable.
As a material for forming the negative electrode current collector, in addition to aluminum, copper, copper alloy, stainless steel, nickel and titanium, carbon, nickel, titanium or silver is treated on the surface of aluminum, copper, copper alloy or stainless steel. The one that has been made is preferable. Among them, aluminum, copper, copper alloy and stainless steel are more preferable.

The shape of the current collector 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, or the like can also be used.
The thickness of the current collector is not particularly limited, but is preferably 1 to 500 μm. Further, it is also preferable that the surface of the current collector is made uneven by surface treatment.

In the present invention, a functional layer, a member, or the like is appropriately interposed or arranged between or outside each of the negative electrode current collector, the negative electrode active material layer, the solid electrolyte layer, the positive electrode active material layer, and the positive electrode current collector. You may. Further, each layer may be composed of a single layer or a plurality of layers.

<Manufacturing method of all-solid-state secondary battery>
An example of the method for manufacturing the all-solid-state secondary battery of the present invention is shown below, but the method for manufacturing the all-solid-state secondary battery of the present invention is not limited to these forms.
(Aspect in which the entire end of the battery element member is covered with an inorganic insulating coating)
A composition (composition for a positive electrode) containing components constituting a positive electrode active material layer is applied onto a base material (for example, a metal foil serving as a current collector) to form a positive electrode active material layer, and an all-solid secondary A positive electrode sheet for a battery is produced. Next, a composition containing at least the above-mentioned inorganic solid electrolyte material is applied onto the positive electrode active material layer to form a solid electrolyte layer.
After that, by superimposing the negative electrode active material layer and the negative electrode current collector (metal foil) on the solid electrolyte layer, the solid electrolyte layer is sandwiched between the positive electrode active material layer and the negative electrode active material layer. Get a secondary battery. Then, these battery element members are packed in a housing that becomes a battery exterior.
Next, a mixture of the above-mentioned insulating inorganic material and the above-mentioned inorganic insulating particles is arranged at the end of the battery element member in the housing. Next, the insulating inorganic material is heated to a temperature at which it is thermally melted (preferably 200 ° C. or lower), and the melt of the insulating inorganic material is spread between the particles constituting the mixture to reach the end of the battery element member. Form an inorganic insulating coating.

Further, by reversing the forming method of each layer, a negative electrode active material layer, a solid electrolyte layer and a positive electrode active material layer are formed on the negative electrode current collector, and the positive electrode current collectors are superposed to manufacture an all-solid secondary battery. You can also do it. Further, a two-layer structure laminate composed of a base material / negative electrode active material layer and a three-layer structure laminate composed of a base material / positive electrode active material layer / solid electrolyte layer are prepared, and these are laminated to form the present invention. All-solid-state secondary batteries can also be obtained. Further, a two-layer structure laminate composed of a base material / positive electrode active material layer and a three-layer structure laminate composed of a base material / negative electrode active material layer / solid electrolyte layer are prepared, and these are superposed to form a battery element member. You can also get.

Further, as shown below, the inorganic insulating coating is applied to (a) only the end of the solid-charged lipid layer, (b) only the end of the positive electrode active material layer and the end of the solid-charged lipid layer, or (c) the positive electrode collection. It may be provided only at the end of the electric body, the end of the positive electrode active material layer, and the end of the solid-charged lipid layer. These forms are also preferable as the forms of the all-solid-state secondary battery of the present invention.
(A mode in which a part of the end portion of the battery element member is covered with an inorganic insulating coating)
A composition (composition for a positive electrode) containing components constituting a positive electrode active material layer is applied onto a base material (for example, a metal foil serving as a current collector) to form a positive electrode active material layer, and an all-solid secondary A positive electrode sheet for a battery is produced. Next, a composition containing at least the above-mentioned inorganic solid electrolyte material is applied onto the positive electrode active material layer to form a solid electrolyte layer. Further, a mixture of the above-mentioned insulating inorganic material and inorganic insulating particles is arranged at both ends of the solid electrolyte layer. The mixture may be formed up to the edge of the substrate and / or the edge of the positive electrode active material layer. The insulating inorganic material is then heated to a temperature at which it thermally melts (preferably 200 ° C. or lower) to spread the melt of the insulating inorganic material to the edges of the inorganic solid electrolyte material and between the particles constituting the mixture. Let me. Then, the solid electrolyte layer end or the positive electrode active material layer end and the solid electrolyte layer end or cathode current collector end and the positive electrode active material layer end and the solid electrolytic membrane layer end in the inorganic insulating coating body Form.
Then, a composition containing a component forming the negative electrode active material layer as a negative electrode material is applied onto the solid electrolyte layer to form the negative electrode active material layer. By superimposing a negative electrode current collector (metal foil) on the negative electrode active material layer, an all-solid secondary battery having a structure in which a solid electrolyte layer is sandwiched between the positive electrode active material layer and the negative electrode active material layer can be obtained. Can be done. If necessary, this can be enclosed in a housing that serves as a battery exterior to obtain a desired all-solid-state secondary battery.

Further, a solid electrolyte sheet having an inorganic insulating coating at the end and / or a positive electrode active material sheet having an inorganic insulating coating at the end, which will be described later, are prepared in advance, and the battery element member is used by using these sheets. Can also be produced to obtain the all-solid-state secondary battery of the present invention.

In the above example, the heating for melting the insulating inorganic material is performed immediately after the mixture is placed on the target end portion. Further, the present invention is not limited to this embodiment. That is, the mixture may be heated at any stage in the manufacturing process of the all-solid-state secondary battery as long as it is placed at the target end using the mixture. Further, the step of arranging the mixture at the target end portion can be performed at a temperature equal to or higher than the melting temperature of the insulating inorganic material. In this case, it is necessary to separately provide a heating step for melting the insulating inorganic material. It may not be there.

(Formation method of each layer)
In the production of the all-solid-state secondary battery of the present invention, the method for forming the solid electrolyte layer and the active material layer is not particularly limited and can be appropriately selected. For example, coating (preferably wet coating), spray coating, spin coating coating, dip coating, slit coating, stripe coating and bar coating coating can be mentioned.
At this time, the drying treatment may be performed after the coating, or the drying treatment may be performed after the multi-layer coating. The drying temperature is not particularly limited. The lower limit is preferably 30 ° C. or higher, more preferably 60 ° C. or higher, and even more preferably 80 ° C. or higher. The upper limit is preferably 300 ° C. or lower, more preferably 250 ° C. or lower, and even more preferably 200 ° C. or lower. By heating in such a temperature range, the dispersion medium (C) can be removed and the solid state can be obtained. Further, it is preferable because the temperature is not raised too high and each member of the all-solid-state secondary battery is not damaged. As a result, in the all-solid-state secondary battery, excellent overall performance can be exhibited and good binding property can be obtained.

The produced all-solid-state secondary battery is preferably pressurized. Examples of the pressurizing method include a hydraulic cylinder press machine and the like. The pressing force is not particularly limited, and is generally preferably in the range of 50 to 1500 MPa.
Further, the applied solid electrolyte composition may be heated at the same time as pressurization. The heating temperature is not particularly limited, and is generally in the range of 30 to 300 ° C. It can also be pressed at a temperature higher than the glass transition temperature of the inorganic solid electrolyte.
The pressurization may be performed in a state where the coating solvent or the dispersion medium is dried in advance, or may be performed in a state where the solvent or the dispersion medium remains.

The atmosphere during pressurization is not particularly limited, and may be any of air, dry air (dew point −20 ° C. or lower), inert gas (for example, argon gas, helium gas, nitrogen gas) and the like.
The pressing time may be short (for example, within several hours) and high pressure may be applied, or medium pressure may be applied for a long time (1 day or more). In the case of an all-solid-state secondary battery other than the all-solid-state secondary battery sheet, for example, in the case of an all-solid-state secondary battery, an all-solid-state secondary battery restraint (screw tightening pressure, etc.) can be used in order to continue applying a medium pressure.
The press pressure may be uniform or different with respect to the pressed portion such as the sheet surface.
The press pressure can be changed according to the area and film thickness of the pressed portion. It is also possible to change the same part step by step with different pressures.
The pressed surface may be smooth or roughened.

Also, the battery is formed into a sheet, the battery seat a cylindrical type in which the state wound into a roll on the outer periphery of the axis, a form put pressure on the axial direction from the outermost layer of the cylindrical battery You can also.

(Initialize)
The all-solid-state secondary battery manufactured as described above is preferably initialized after manufacturing or before use. The initialization method is not particularly limited, and for example, the initial charge / discharge may be performed with the press pressure increased, and then the pressure may be released until the pressure reaches the general working pressure of the all-solid-state secondary battery.

<Use of all-solid-state secondary battery>
The all-solid-state secondary battery of the present invention can be applied to various applications. The application mode is not particularly limited, but is mounted on, for example, an electronic device. Examples of electronic devices include laptop computers, pen input personal computers, mobile personal computers, electronic book players, mobile phones, cordless phone handsets, pagers, handy terminals, mobile fax machines, mobile copies, and mobile printers. It is also installed in audio and video equipment such as headphone stereos, video movies, LCD TVs, portable CD players, mini disc players, portable tape recorders, and radios. Further, on-board devices include handy cleaners, electric shavers, transceivers, electronic organizers, desktop computers, memory cards, backup power supplies, and the like. Other consumer products include automobiles, 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.

Above all, it is preferable to apply it to an application that requires high capacity and high rate discharge characteristics. For example, high safety is indispensable for power storage equipment and the like whose capacity is expected to increase in the future, and further compatibility of battery performance is required. In addition, electric vehicles and the like are equipped with high-capacity secondary batteries and are expected to be used for daily charging at home. According to the present invention, it is possible to exert its excellent effect in a suitable manner corresponding to such a usage pattern.

[Solid electrolyte sheet for all-solid secondary batteries]
The solid electrolyte sheet for an all-solid-state secondary battery of the present invention (hereinafter, also simply referred to as "electrolyte sheet of the present invention") is suitably used as a member for providing a solid electrolyte layer of the all-solid-state secondary battery of the present invention. Can be done. That is, the electrolyte sheet of the present invention has a solid electrolyte layer and an inorganic insulating coating that covers both ends of the solid electrolyte layer. This inorganic insulating coating has a Young's modulus of 1 GPa or more. Such inorganic insulating coatings include those described above.

[Positive electrode active material sheet for all-solid-state secondary batteries]
The positive electrode active material sheet for an all-solid-state secondary battery of the present invention (hereinafter, also simply referred to as “the positive electrode active material sheet of the present invention”) is a member that provides the positive electrode active material layer of the all-solid-state secondary battery of the present invention. It can be preferably used. That is, the positive electrode active material sheet of the present invention has an inorganic insulating coating that covers both ends of the positive electrode active material layer. This inorganic insulating coating has a Young's modulus of 1 GPa or more. Such inorganic insulating coatings include those described above.

The solid electrolyte sheet can be produced, for example, as follows.
A composition containing the above-mentioned inorganic solid electrolyte material is applied onto a base material (for example, a metal foil serving as a negative electrode current collector) to form a solid electrolyte layer to prepare a solid electrolyte sheet for an all-solid secondary battery. .. Next, a mixture of the above-mentioned insulating inorganic material and inorganic insulating particles is applied to both ends of the solid electrolyte layer. The mixture may be formed up to the edge of the substrate. The insulating inorganic material is then heated to a temperature at which it thermally melts (preferably 200 ° C. or lower) to spread the melt of the insulating inorganic material to the edges of the inorganic solid electrolyte material and between the particles constituting the mixture. Then, an inorganic insulating coating is formed at the end of the solid electrolyte layer.
Further, the positive electrode active material sheet can be produced, for example, as follows.
A composition (composition for a positive electrode) containing components constituting a positive electrode active material layer is applied onto a base material (for example, a metal foil serving as a current collector) to form a positive electrode active material layer, and an all-solid secondary A positive electrode active material sheet for a battery is prepared. Next, a mixture of the above-mentioned insulating inorganic material and inorganic insulating particles is applied to both ends of the positive electrode active material layer. The mixture may be formed up to the edge of the substrate. The insulating inorganic material is then heated to a temperature at which it thermally melts (preferably 200 ° C. or lower) to spread the melt of the insulating inorganic material to the edges of the positive electrode active material layer and between the particles constituting the mixture. At the same time, an inorganic insulating coating is formed at the end of the positive electrode active material layer.
The application of the mixture of the insulating inorganic material can be carried out, for example, by using a dispersion liquid in which a mixture of sulfur and aluminum oxide (alumina) particles is dispersed with toluene.

The present invention will be described in more detail based on examples, but the present invention is not limited to these embodiments.

[Reference Example 1] Inorganic solid electrolyte argon atmosphere in a glove box (dew point -70 ° C.), lithium sulfide _(Li 2 S, Aldrich Corp., purity> 99.98%) 2.42 g, pentasulfide phosphorus _{(P 2} S 5, Aldrich Co., purity> 99%) of 3.90g were weighed, were placed in an agate mortar. Li ₂ S and P ₂ S ₅ have a molar ratio of Li ₂ S: P ₂ S ₅ = 75: 25. On the agate mortar, the mixture was mixed for 5 minutes using an agate pestle.
66 zirconia beads having a diameter of 5 mm were put into a 45 mL container made of zirconia (manufactured by Fritsch), the whole amount of the above mixture was put into the container, and the container was completely sealed under an argon atmosphere. A container is set in a planetary ball mill P-7 manufactured by Fritsch, and mechanical milling is performed at 25 ° C. at a rotation speed of 510 rpm for 20 hours to obtain a yellow powder sulfide-based inorganic solid electrolyte (Li / P / S glass, hereinafter "Li / P / S glass". Also referred to as "LPS") 6.2 g was obtained.
The volume average particle size of the obtained LPS was measured using a laser diffraction / scattering type particle size distribution measuring device LA-920 (trade name, manufactured by HORIBA) and found to be 8 μm.

[Reference Example 2] Preparation of a mixture of sulfur and inorganic insulating particles Under air, 1.2 g of sulfur (S, manufactured by Aldrich, purity> 99.98%), aluminum oxide nanoparticles (Al ₂ O ₃ , purity> 99%, particle size 500 nm, manufactured by EM Japan Co., Ltd.) 1.2 g were weighed. They were placed in an agate mortar and mixed for 10 minutes using an agate pestle.

[Manufacturing example] Manufacture of all-solid-state secondary battery 180 zirconia beads with a diameter of 5 mm were placed in a zirconia 45 mL container (manufactured by Fritsch), and 2.0 g of LPS synthesized above and styrene-butadiene rubber (product code 182907, 0.1 g (manufactured by Aldrich) and 22 g of octane as a dispersion medium were added. After that, this container was set in a planetary ball mill P-7 manufactured by Fritsch, and stirred at a temperature of 25 ° C. and a rotation speed of 300 rpm for 2 hours. Then, 7.9 g of the positive electrode active material LiNi _0.85 Co _0.10 Al _0.05 O ₂ (lithium nickel cobalt aluminate) was put into a container, and this container was set in the planetary ball mill P-7 again, and the temperature was 25. Mixing was continued for 15 minutes at ° C. and 100 rpm. In this way, a composition for a positive electrode was obtained.
Next, by a conventional method, a composition (composition for positive electrode) containing the components constituting the positive electrode active material obtained above was placed on an aluminum foil having a thickness of 20 μm as a current collector together with 2% by mass of a binder in a baker type applicator. And heated at 80 ° C. for 2 hours to dry the positive electrode composition. Then, using a heat press machine, the composition for the positive electrode layer dried to a predetermined density was pressurized (600 MPa, 1 minute) while heating (120 ° C.). In this way, a positive electrode sheet for an all-solid secondary battery having a positive electrode active material having a film thickness of 110 μm was produced.

Next, the inorganic solid electrolyte prepared according to Reference Example 1 was dispersed in toluene at room temperature together with 2% by mass of the binder to obtain a coating liquid having a solid content of 20% by mass. This coating liquid was bar-coated on the positive electrode at room temperature, heated to 120 ° C. and dried to obtain a solid electrolyte layer having a width of 50 mm and a film thickness of 100 μm.
Next, a stainless steel (SUS) foil having a width of 50 mm, which serves as a negative electrode current collector, was laminated on the solid electrolyte layer to form a laminated body sheet for an all-solid secondary battery.
A commercially available insulating separator (width 50 mm) is superposed on the outer circumference of the positive electrode current collector of this laminated body sheet, and wound around the outer circumference of a stainless steel cylindrical shaft core so that the current collector is not short-circuited, and has a diameter of 26 mm and a thickness of 0. It was packed in a 1 mm, 65 mm long stainless steel cylindrical battery case. The center of the cylinder is a cylinder with a diameter of 18 mm, a thickness of 0.1 mm, and a length of 65 mm, with slits (length 9 mm, width 0.1 mm, spacing between slits 1 mm) so that it can be broken by internal pressure. Is.
Then, a reinforced cylindrical cover made of stainless steel and having a wall thickness of 5 mm was fitted on the outside of the cylindrical battery case.

Then, activated carbon is filled in the cylindrical shaft core, and the activated carbon is compressed from both sides of the cylindrical shaft core at a pressure of 24 Pa with a press machine to widen the slit width of the cylindrical shaft core and increase the diameter of the cylindrical shaft core. rice field. Due to the increase in diameter, a predetermined restraining pressure was applied to the laminate between the outer case and the cylindrical shaft core.
The negative electrode current collector was made conductive with the battery outer case, and the positive electrode current collector was made conductive with the shaft core so that the current could be taken out to the outside.
The mixture obtained in Reference Example 2 was arranged at both ends of the battery element member between the cylindrical shaft core and the outer case, compressed with a press machine at a pressure of 24 Pa, and pressed.
The laminate coated with the insulating coating was heated on a hot plate at 150 ° C. for 30 minutes to thermally melt sulfur as a filler.
Then, it was naturally cooled to seal the case to obtain an all-solid-state secondary battery having an inorganic insulating coating. The inorganic insulating coating after natural cooling had a Young's modulus of 50 GPa at 25 ° C.
Further, for comparison, an all-solid-state secondary battery having no inorganic insulating coating, which was obtained in the same step except that the step of arranging the inorganic insulating coating was not performed, was obtained.

[Test Example 1] Charge / discharge test (test method)
Using each all-solid-state secondary battery produced as described above, charge and discharge are performed under the following conditions, and the ratio of the initial discharge capacity to the initial charge capacity (discharge efficiency (%) = 100 x [initial discharge capacity / initial charge capacity]). Was calculated.
The charging / discharging conditions were a temperature of 30 ° C. in the measurement environment, a current density of 0.09 mA / cm ² (corresponding to 0.05 C), 4.2 V, and a constant current condition.

[Test Example 2] Charge / discharge cycle characteristic test (test method)
Using an all-solid-state secondary battery (one having an inorganic insulating coating and one without an inorganic insulating coating) manufactured in the same manner as in the above production example, a charge / discharge cycle characteristic test was conducted under the following conditions. Then, the ratio of the discharge capacity of the second cycle to the first discharge capacity in the charge / discharge cycle (discharge capacity retention rate (%) = 100 × [discharge capacity of the second cycle / initial discharge capacity]) was calculated.
The charging / discharging conditions were a temperature of 30 ° C. in the measurement environment, a current density of 0.09 mA / cm ² (corresponding to 0.05 C), 4.2 V, and a constant current condition.
The results are shown in the table below.

As shown in the above table, it was found that the discharge efficiency is enhanced and the discharge capacity retention rate is also enhanced by having the inorganic insulating coating at the end of the battery element member.

The present application claims priority based on Japanese Patent Application No. 2017-047772 filed in Japan on March 13, 2017, which is referred to herein and is described herein. Incorporate as a part.

10 All-solid secondary battery 1 Negative electrode current collector 2 Negative electrode active material layer 3 Solid electrolyte layer 4 Positive electrode active material layer 5 Positive electrode current collector 6 Working part 21a Solid electrolyte layer 21b Positive electrode current collector 21c Positive electrode active material layer 21d Negative electrode collection collector 21e the anode active material layer 22 axis 23 battery cover 24 inorganic insulating coating material 25 positive electrode tab 26 electrode positive 27 negative electrode tab 28 battery negative

Claims (16)

An all-solid-state secondary battery having a battery element member,
The battery element member has at least a negative electrode current collector, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector.
An inorganic insulating coating that covers at least the end of the battery element member and has a Young's modulus of 1 GPa or more at 25 ° C. is arranged at the end of the battery element member.
The inorganic insulating coating comprises inorganic insulating particles and a melt-solidified body of an insulating inorganic material that is solid at 100 ° C. and melts in a temperature range of 200 ° C. or lower.
The inorganic insulating coating contains an organic binder.
All-solid-state secondary battery. An all-solid-state secondary battery having a battery element member,
The battery element member has at least a negative electrode current collector, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector.
An inorganic insulating coating that covers at least the end of the battery element member and has a Young's modulus of 1 GPa or more at 25 ° C. is arranged at the end of the battery element member.
The inorganic insulating coating comprises inorganic insulating particles and a melt-solidified body of an insulating inorganic material that is solid at 100 ° C. and melts in a temperature range of 200 ° C. or lower.
Ri is 50 to 90% by mass amount of the inorganic insulating particles of the inorganic insulating coating material in,
An all-solid-state secondary battery in which the inorganic insulating particles constituting the inorganic insulating coating are the following (a), (b) or (c) :
(A) Inorganic insulating particles selected from aluminum oxide, zirconium oxide, silicon oxide, zeolite, cubic boron nitride, hexagonal boron nitride, and cerium oxide;
(B) Inorganic insulating particles that do not melt at 250 ° C;
(C) Inorganic insulating particles that are not melt-solidified bodies . The all-solid-state secondary battery according to claim 1 or 2, which has a battery exterior in which the battery element member is inserted therein. The all-solid-state secondary battery according to any one of claims 1 to 3, wherein the inorganic insulating particles are aluminum oxide having a volume average particle diameter of 1 μm or less. The all-solid-state secondary battery according to any one of claims 1 to 4, wherein the insulating inorganic material contains sulfur and / or modified sulfur. The all-solid-state secondary battery according to any one of claims 1 to 5, wherein the inorganic insulating coating prevents the growth of metallic lithium that grows from the negative end end during charging and discharging. A step of arranging a battery element member including at least a negative electrode current collector, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector inside the battery exterior.
A step of arranging inorganic insulating particles, an insulating inorganic material that is solid at 100 ° C. and melts in a temperature range of 200 ° C. or lower, and an organic binder at the end of the battery element member in the space inside the battery exterior.
In 200 ° C. below the temperature range by heating the battery outer body, wherein the insulating inorganic material is melted solidifying includes the step of covering the end portion of the battery element member, according to claim 1 total A method for manufacturing a solid-state secondary battery. A step of arranging a battery element member including at least a negative electrode current collector, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector inside the battery exterior.
A step of arranging inorganic insulating particles and an insulating inorganic material that is solid at 100 ° C. and melts in a temperature range of 200 ° C. or lower at the end of the battery element member in the space inside the battery exterior.
And heating the battery exterior body at 200 ° C. below the temperature region, the insulating inorganic material is melted solidified, see containing and a step of covering the end portion of the battery element member,
The inorganic insulating particles are the following (a) or (b) or (c'):
(A) Inorganic insulating particles selected from aluminum oxide, zirconium oxide, silicon oxide, zeolite, cubic boron nitride, hexagonal boron nitride, and cerium oxide;
(B) Inorganic insulating particles that do not melt at 250 ° C;
(C') Inorganic insulating particles that do not melt in the step of coating the end portion of the battery element member;
The content of the inorganic insulating particles in the inorganic insulating coating formed by the step of coating the end portion of the battery element member is 50 to 90% by mass.
The method for manufacturing an all-solid-state secondary battery according to claim 2. A solid electrolyte sheet used in the all-solid-state secondary battery according to claim 1.
It has a solid electrolyte layer and an inorganic insulating coating that covers the ends of the solid electrolyte layer.
The inorganic insulating coating is composed of inorganic insulating particles, a melt-solidified body of an insulating inorganic material that is solid at 100 ° C. and melts in a temperature range of 200 ° C. or lower, and an organic binder, and has a Young ratio of 1 GPa at 25 ° C. The above is the solid electrolyte sheet for all-solid secondary batteries. A solid electrolyte sheet used in the all-solid-state secondary battery according to claim 2.
It has a solid electrolyte layer and an inorganic insulating coating that covers the ends of the solid electrolyte layer.
The inorganic insulating coating is composed of inorganic insulating particles and a melt-solidified body of an insulating inorganic material that is solid at 100 ° C. and melts in a temperature range of 200 ° C. or lower, and has a Young's modulus of 1 GPa or more at 25 ° C.
Ri is 50 to 90% by mass amount of the inorganic insulating particles of the inorganic insulating coating material in,
A solid electrolyte sheet for an all-solid secondary battery , wherein the inorganic insulating particles constituting the inorganic insulating coating are the following (a), (b) or (c) :
(A) Inorganic insulating particles selected from aluminum oxide, zirconium oxide, silicon oxide, zeolite, cubic boron nitride, hexagonal boron nitride, and cerium oxide;
(B) Inorganic insulating particles that do not melt at 250 ° C;
(C) Inorganic insulating particles that are not melt-solidified bodies . The solid electrolyte sheet for an all-solid secondary battery according to claim 9 or 10, wherein the insulating inorganic material contains sulfur and / or modified sulfur. The solid electrolyte sheet for an all-solid secondary battery according to any one of claims 9 to 11, wherein the inorganic insulating particles are aluminum oxide. A positive electrode active material sheet used in the all-solid-state secondary battery according to claim 1.
It has a positive electrode active material layer and an inorganic insulating coating that covers both ends of the positive electrode active material layer.
The inorganic insulating coating is composed of inorganic insulating particles, a melt-solidified body of an insulating inorganic material that is solid at 100 ° C. and melts in a temperature range of 200 ° C. or lower, and an organic binder, and has a Young ratio of 1 GPa at 25 ° C. The above is the positive electrode active material sheet for all-solid secondary batteries. A positive electrode active material sheet used in the all-solid-state secondary battery according to claim 2.
It has a positive electrode active material layer and an inorganic insulating coating that covers both ends of the positive electrode active material layer.
The inorganic insulating coating is composed of inorganic insulating particles and a melt-solidified body of an insulating inorganic material that is solid at 100 ° C. and melts in a temperature range of 200 ° C. or lower, and has a Young's modulus of 1 GPa or more at 25 ° C.
Ri is 50 to 90% by mass amount of the inorganic insulating particles of the inorganic insulating coating material in,
Positive electrode active material sheet for all-solid-state secondary battery in which the inorganic insulating particles constituting the inorganic insulating coating are the following (a), (b) or (c) :
(A) Inorganic insulating particles selected from aluminum oxide, zirconium oxide, silicon oxide, zeolite, cubic boron nitride, hexagonal boron nitride, and cerium oxide;
(B) Inorganic insulating particles that do not melt at 250 ° C;
(C) Inorganic insulating particles that are not melt-solidified bodies . The positive electrode active material sheet for an all-solid secondary battery according to claim 13 or 14, wherein the insulating inorganic material contains sulfur and / or modified sulfur. The positive electrode active material sheet for an all-solid-state secondary battery according to any one of claims 13 to 15, wherein the inorganic insulating particles are aluminum oxide.

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