JP6607694B2 - All-solid secondary battery, composition for electrode active material layer, electrode sheet for all-solid secondary battery, electrode sheet for all-solid secondary battery, and method for producing all-solid secondary battery - Google Patents

Description

  The present invention relates to an all-solid secondary battery, an electrode active material layer composition used therefor, an electrode sheet for an all-solid secondary battery, an electrode sheet for an all-solid secondary battery, and a method for producing an all-solid secondary battery.

Electrolytic solutions have been used for lithium ion batteries. Attempts have been made to replace the electrolytic solution with a solid electrolyte to obtain an all-solid-state secondary battery in which the constituent materials are all solid. An advantage of the technology using an inorganic solid electrolyte is the reliability of the overall performance of the battery. For example, a flammable material such as a carbonate-based solvent is applied as a medium to an electrolytic solution used in a lithium ion secondary battery. Although various safety measures have been taken, it cannot be said that there is no risk of problems during overcharging, and further measures are desired. An all-solid-state secondary battery that can make the electrolyte nonflammable is positioned as a fundamental solution.
A further advantage of the all-solid-state secondary battery is that it is suitable for increasing the energy density by stacking electrodes. Specifically, a battery having a structure in which an electrode and an electrolyte are directly arranged in series can be obtained. At this time, since the metal package for sealing the battery cell, the copper wire and the bus bar for connecting the battery cell can be omitted, the energy density of the battery is greatly increased. In addition, good compatibility with the positive electrode material capable of increasing the potential is also mentioned as an advantage.

  Development of an all-solid secondary battery as a next-generation lithium ion battery has been promoted from the above advantages (Non-patent Document 1). For example, in Patent Document 1, all solids using a laminate composed of a sintered body in which a specific intermediate layer is interposed between an electrode layer and a solid electrolyte layer containing a Li-containing oxide having a garnet crystal structure. A secondary battery is described. Patent Document 2 describes an all solid lithium ion secondary battery having an electrode mixture layer containing active material particles and ion conductive auxiliary (solid electrolyte) particles.

JP 2014-110149 A JP 2014-035818 A

NEDO Technology Development Organization, Fuel Cell / Hydrogen Technology Development Department, Energy Storage Technology Development Office “NEDO Next-Generation Automotive Storage Battery Technology Development Roadmap 2013” (August 2013)

In the all-solid-state secondary battery described in Patent Document 1, since an oxide-based solid electrolyte is used for the solid electrolyte layer, the ionic conductivity is low, and the battery output is not sufficient.
Moreover, in the all-solid-state lithium ion secondary battery described in Patent Document 2, the electrode mixture layer and the solid electrolyte layer are produced by a dry process such as sintering or compacting in the absence of a binder. Therefore, a good interface is not formed between the active material particles and the ion conductive auxiliary particles, and increasing the ratio of the active material particles in the electrode mixture layer increases the capacity of the battery. There is a problem that the ion conduction path by the agent particles is hardly formed, and the output of the battery is lowered.

  Therefore, the present invention provides an all-solid secondary battery having a high energy density and output density per weight of the battery, an electrode active material layer composition used therefor, an electrode sheet for an all-solid secondary battery, and an all-solid secondary battery. It is an object of the present invention to provide a method for manufacturing an electrode sheet and an all-solid-state secondary battery.

As a result of intensive studies by the present inventors, the content of the inorganic solid electrolyte in at least one electrode active material layer is reduced, and at least one electrode active material layer contains a binder for improving the adhesion between solid particles. The all-solid-state secondary battery in which the solid electrolyte layer contains a sulfide-based solid electrolyte with high ion conductivity and the negative electrode active material layer contains a specific negative electrode active material has either an energy density or a power density per battery weight. I also found it excellent. Further, the electrode sheet for an all-solid secondary battery and the method for producing an all-solid secondary battery of the present invention having an effect of improving the adhesion between solid particles by a wet process are the production of the all-solid-state secondary battery having the above excellent performance. It was found to be excellent. The present invention has been made based on these findings.
That is, the above problem has been solved by the following means.
(1) An all-solid secondary battery having a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order,
In at least one of the positive electrode active material layer and the negative electrode active material layer, the content of the inorganic solid electrolyte in the total solid content of the layer is 0 to 10% by mass,
At least one of the positive electrode active material layer and the negative electrode active material layer in which the content of the inorganic solid electrolyte in the total solid content is 0 to 10% by mass, the content of the electrode active material in the total solid content of the layer is 90% by mass. % Or more,
The solid electrolyte layer contains a sulfide-based solid electrolyte, and the content of the sulfide-based solid electrolyte is 90% by mass or more in the total solid content constituting the solid electrolyte layer,
At least one of the positive electrode active material layer and the negative electrode active material layer contains a binder,
The negative electrode active material layer contains a negative electrode active material represented by the following formula (α), and
Among the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer, at least one layer including the solid electrolyte layer contains a dispersant,
The dispersant has a molecular weight of 180 or more and less than 3,000, and at least one functional group selected from the following functional group group (I) and an alkyl group having 8 to 30 carbon atoms or 10 to 30 carbon atoms. An all-solid secondary battery, which is a compound having the following aryl group:
Li _xα M ^α _yα O _zα formula (α)
In the formula (α), M ^α represents an element selected from Al, Ga, In, Ti, Si, Sn, Ge, Pb, Sb, Nb, W, Mo, Fe, and Bi. xα to zα represent the composition ratio of each element, and xα = 0 to 4, yα = 0.3 to 7, and zα = 0.5 to 15.
Functional group (I): an acidic group, a group having a basic nitrogen atom, and a cyano group .
(2) all-solid secondary battery according to the negative electrode active material is _{Li 4 Ti 5 O 12 (1} ).
( 3 ) The all solid state secondary battery according to (1) or (2) , wherein the thickness of at least one of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer is 50 μm or more and less than 500 μm.
( 4 ) The all-solid-state secondary battery according to any one of (1) to ( 3 ), wherein at least one kind of binder is polymer particles having an average particle diameter of 0.05 μm to 20 μm.
( 5 ) The all solid state secondary battery according to any one of (1) to ( 4 ), wherein at least one of the binders has a partial structure represented by the following formula (I).

In formula (I), R represents a hydrogen atom or a monovalent organic group.
( 6 ) The all-solid secondary according to any one of (1) to ( 5 ), wherein the solid electrolyte layer wet-coats a slurry in which the sulfide-based solid electrolyte is dispersed by a non-aqueous dispersion medium and forms a film. A battery manufacturing method.
( 7 ) A composition for an electrode active material layer that forms a positive electrode active material layer or a negative electrode active material layer of an all-solid-state secondary battery according to any one of (1) to ( 5 ),
The composition for the electrode active material layer is
The content of the inorganic solid electrolyte is 0 to 10% by mass in the total solid content constituting the composition for the electrode active material layer, contains the electrode active material, the binder and the dispersant, and the content of the electrode active material is 90% by mass or more in the total solid content constituting the composition for electrode active material layer,
The electrode active material contained in the composition for electrode active material layer forming the negative electrode active material layer is a negative electrode active material represented by the following formula (α),
The dispersant has a molecular weight of 180 or more and less than 3,000, and at least one functional group selected from the following functional group group (I) and an alkyl group having 8 to 30 carbon atoms or 10 to 30 carbon atoms. The composition for electrode active material layers which is a compound which has the following aryl groups.
Li _xα M ^α _yα O _zα formula (α)
In the formula (α), M ^α represents an element selected from Al, Ga, In, Ti, Si, Sn, Ge, Pb, Sb, Nb, W, Mo, Fe, and Bi. xα to zα represent the composition ratio of each element, and xα = 0 to 4, yα = 0.3 to 7, and zα = 0.5 to 15.
Functional group (I): an acidic group, a group having a basic nitrogen atom, and a cyano group.
( 8 ) A method for producing an electrode sheet for an all-solid-state secondary battery, wherein the composition for electrode active material layer according to ( 7 ) is applied onto a metal foil to form a film.
( 9 ) An electrode sheet for an all-solid secondary battery having a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order,
In at least one of the positive electrode active material layer and the negative electrode active material layer, the content of the inorganic solid electrolyte in the total solid content of the layer is 0 to 10% by mass,
At least one of the positive electrode active material layer and the negative electrode active material layer in which the content of the inorganic solid electrolyte in the total solid content is 0 to 10% by mass, the content of the electrode active material in the total solid content of the layer is 90% by mass. % Or more,
The solid electrolyte layer contains a sulfide-based solid electrolyte, and the content of the sulfide-based solid electrolyte is 90% by mass or more in the total solid content constituting the solid electrolyte layer,
At least one of the positive electrode active material layer and the negative electrode active material layer contains a binder,
The negative electrode active material layer contains a negative electrode active material represented by the following formula (α), and
Among the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer, at least one layer including the solid electrolyte layer contains a dispersant,
The dispersant has a molecular weight of 180 or more and less than 3,000, and at least one functional group selected from the following functional group group (I) and an alkyl group having 8 to 30 carbon atoms or 10 to 30 carbon atoms. An electrode sheet for an all-solid-state secondary battery, which is a compound having the following aryl group.
Li _xα M ^α _yα O _zα formula (α)
In the formula (α), M ^α represents an element selected from Al, Ga, In, Ti, Si, Sn, Ge, Pb, Sb, Nb, W, Mo, Fe, and Bi. xα to zα represent the composition ratio of each element, and xα = 0 to 4, yα = 0.3 to 7, and zα = 0.5 to 15.
Functional group (I): an acidic group, a group having a basic nitrogen atom, and a cyano group.

In this specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
In this specification, when there are a plurality of substituents indicated by a specific symbol, or when a plurality of substituents etc. (same as the definition of the number of substituents) are specified simultaneously or alternatively, each substituent etc. They may be the same or different from each other. Further, when a plurality of substituents and the like are close to each other, they may be bonded to each other or condensed to form a ring.
In this specification, when it is simply described as “acryl”, it is used in the meaning including both methacryl and acrylic.

  The all-solid-state secondary battery of the present invention has both high energy density and output density per weight of the battery, and the above-mentioned excellent performance is achieved by the electrode sheet for all-solid-state secondary battery and the method for producing all-solid-state secondary battery of the present invention. All-solid-state secondary batteries having excellent performance can be suitably manufactured. Furthermore, the composition for an electrode active material layer and the electrode sheet for an all solid secondary battery of the present invention can be suitably used for providing an all solid secondary battery having the above-described excellent performance.

It is a longitudinal cross-sectional view which shows typically the all-solid-state lithium ion secondary battery which concerns on preferable embodiment of this invention. It is a longitudinal cross-sectional view which shows typically the testing apparatus utilized in the Example.

The all-solid-state secondary battery of the present invention has a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order,
The content of the inorganic solid electrolyte in at least one of the positive electrode active material layer and the negative electrode active material layer is 0 to 10% by mass with respect to the total solid content constituting each layer,
The solid electrolyte layer contains a sulfide-based solid electrolyte,
At least one of the positive electrode active material layer and the negative electrode active material layer contains a binder, and
The negative electrode active material layer contains a negative electrode active material represented by the formula (α) described later.
Here, in this invention, the inorganic solid electrolyte in a positive electrode active material layer and a negative electrode active material layer is an arbitrary component.
Hereinafter, the preferable embodiment will be described.

FIG. 1 is a cross-sectional view schematically showing an all solid state secondary battery (lithium ion secondary battery) according to a preferred embodiment of the present invention. The all-solid-state secondary battery 10 of this 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 5 in this order as viewed from the negative electrode side. . Each layer is in contact with each other and has a laminated structure. By adopting such a structure, at the time of charging, electrons (e ⁻ ) are supplied to the negative electrode side, and lithium ions (Li ⁺ ) are accumulated therein. On the other hand, at the time of discharge, lithium ions (Li ⁺ ) accumulated in the negative electrode are returned to the positive electrode side, and electrons are supplied to the working part 6. In the example shown in the figure, a light bulb is adopted as the operation part 6 and is turned on by discharge. The solid electrolyte composition can be preferably used as a molding material for the solid electrolyte layer, and the composition for an electrode active material layer can be preferably used as a molding material for the negative electrode active material layer and the positive electrode active material layer.

  The thicknesses of the positive electrode active material layer 4, the solid electrolyte layer 3, and the negative electrode active material layer 2 are not particularly limited. In consideration of general battery dimensions, 10 to 1,000 μm is preferable, and 20 μm or more and less than 500 μm is more preferable. In the all solid state secondary battery of the present invention, it is more preferable that the thickness of at least one of the positive electrode active material layer 4, the solid electrolyte layer 3, and the negative electrode active material layer 2 is 50 μm or more and less than 500 μm.

<< Constituent elements of each layer >>
Hereinafter, components of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer that constitute the all solid state secondary battery of the present invention will be described. In addition, the component of each layer is preferably applied as a component contained in the solid electrolyte composition and the electrode active material layer composition used as the molding material for the corresponding layer.
In this specification, the positive electrode active material layer and the negative electrode active material layer may be collectively referred to as an electrode active material layer (electrode layer).

(Inorganic solid electrolyte)
The inorganic solid electrolyte is an inorganic solid electrolyte, and the solid electrolyte is a solid capable of moving ions inside thereof.
Since inorganic solid electrolytes do not contain organic substances, that is, carbon atoms, organic solid electrolytes (polymer electrolytes typified by PEO (polyethylene oxide), etc., organics typified by LiTFSI [lithium bis (trifluoromethanesulfonyl) imide], etc. It is clearly distinguished from the electrolyte salt). Further, since the inorganic solid electrolyte is solid in a steady state, the cation and the anion are not dissociated or liberated, and the cation and the anion are dissociated or liberated in the electrolyte or polymer (LiPF ₆ , LiBF ₄ and LiFSI [lithium bis (fluorosulfonyl) imide], LiCl, etc.). The inorganic solid electrolyte is not particularly limited as long as it has conductivity of ions of metals belonging to Group 1 or Group 2 of the periodic table, and generally does not have electron conductivity.

  The inorganic solid electrolyte used in the present invention is preferably an inorganic solid electrolyte having conductivity of ions of metals belonging to Group 1 or Group 2 of the periodic table. As the inorganic solid electrolyte, a solid electrolyte material commonly used for this type of product can be appropriately selected and used. An inorganic solid electrolyte (hereinafter also referred to as a solid electrolyte) includes (i) a sulfide-based inorganic solid electrolyte (hereinafter also referred to as a sulfide-based solid electrolyte) and (ii) an oxide-based inorganic solid electrolyte (hereinafter referred to as an oxide solid). A typical example is an electrolyte.

(I) Sulfide-based inorganic solid electrolyte A sulfide-based solid electrolyte contains sulfur (S), has ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and is an electron. There is no particular limitation as long as it has insulating properties. For example, a lithium ion conductive inorganic solid electrolyte that satisfies the composition represented by the following formula (1) can be given.

_{Li a M b P c S d} A e (1)

  In formula (1), M represents an element selected from B, Zn, Sn, Si, Cu, Ga, Sb, Al, and Ge. Of these, B, Sn, Si, Al, and Ge are preferable, and Sn, Al, and Ge are more preferable. A represents I, Br, Cl or F, preferably I or Br, and particularly preferably I. a to e indicate the composition ratio of each element, and a: b: c: d: e satisfies 1 to 12: 0 to 1: 1: 2 to 12: 0 to 5. a is further preferably 1 to 9, and more preferably 1.5 to 4. b is preferably 0 to 0.5. Further, d is preferably 3 to 7, and more preferably 3.25 to 4.5. e is further preferably 0 to 3, and more preferably 0 to 2.

  In the formula (1), the composition ratio of Li, M, P, S and A is preferably such that b and e are 0, more preferably b = 0 and e = 0 and the ratio of a, c and d ( a: c: d) is a: c: d = 1-9: 1: 3-7, more preferably b = 0, e = 0 and a: c: d = 1.5-4: 1 : 3.25 to 4.5. The composition ratio of each element can be controlled by adjusting the blending amount of the raw material compound when producing the sulfide-based solid electrolyte as described below.

  The sulfide-based solid electrolyte may be amorphous (glass) or crystallized (glass ceramic), or only a part may be crystallized. For example, Li—PS—S glass containing Li, P and S, or Li—PS glass glass ceramic containing Li, P and S can be used.

The ratio of Li ₂ S to P ₂ S ₅ in the Li—PS glass and the Li—PS glass ceramics is a molar ratio of Li ₂ S: P ₂ S ₅ , preferably 65:35 to 35:35. 85:15, more preferably 68:32 to 75:25. By setting the ratio of Li ₂ S and P ₂ S ₅ within this range, the lithium ion conductivity can be increased. Specifically, the lithium ion conductivity can be preferably 1 × 10 ⁻⁴ S / cm or more, more preferably 1 × 10 ⁻³ S / cm or more. Although there is no particular upper limit, it is practical that it is 1 × 10 ⁻¹ or less.

Specific examples of the compound include those using a raw material composition containing, for example, Li ₂ S and a sulfide of an element belonging to Group 13 to Group 15. _{Specifically, Li 2 S-P 2 S} 5, Li 2 S-LiI-P 2 S 5, Li 2 S-LiI-Li 2 O-P 2 S 5, Li 2 S-LiBr-P 2 S 5 _{, Li 2 S-Li 2 O} -P 2 S 5, Li 2 S-Li 3 PO 4 -P 2 S 5, Li 2 S-P 2 S 5 -P 2 O 5, Li 2 S-P 2 S 5 _{-SiS 2, Li 2 S-P} 2 S 5 -SnS, Li 2 S-P 2 S 5 -Al 2 S 3, Li 2 S-GeS 2, Li 2 S-GeS 2 -ZnS, Li 2 S-Ga _{2 S 3, Li 2 S-} GeS 2 -Ga 2 S 3, Li 2 S-GeS 2 -P 2 S 5, Li 2 S-GeS 2 -Sb 2 S 5, Li 2 S-GeS 2 -Al 2 S ₃ , Li ₂ S—SiS ₂ , Li ₂ S—Al ₂ S ₃ , Li ₂ S—SiS ₂ —Al _{2 S 3, Li 2 S-} SiS 2 -P 2 S 5, Li 2 S-SiS 2 -P 2 S 5 -LiI, Li 2 S-SiS 2 -LiI, Li 2 S-SiS 2 -Li 4 SiO 4 Li ₂ S—SiS ₂ —Li ₃ PO ₄ , Li ₁₀ GeP ₂ S _{12 and the} like. Among them, Li ₂ S—P ₂ S ₅ , Li ₂ S—GeS ₂ —Ga ₂ S ₃ , Li ₂ S—LiI—P ₂ S ₅ , Li ₂ S—LiI—Li ₂ O—P ₂ S ₅ , _{Li 2 S-GeS 2 -P 2} S 5, Li 2 S-SiS 2 -P 2 S 5, Li 2 S-SiS 2 -Li 4 SiO 4, Li 2 S-SiS 2 -Li 3 PO 4, Li 2 _{S-Li 3 PO 4 -P 2} S 5, Li 2 S-GeS 2 -P 2 S 5, Li 10 GeP 2 crystalline and or amorphous material composition is higher lithium ion conductivity comprised of _{S 12} the Since it has, it is preferable. Examples of a method for synthesizing a sulfide solid electrolyte material using such a raw material composition include an amorphization method. Examples of the amorphization method include a mechanical milling method and a melt quenching method, and among them, the mechanical milling method is preferable. This is because processing at room temperature is possible, and the manufacturing process can be simplified.

(Ii) Oxide-based inorganic solid electrolyte The oxide-based solid electrolyte contains oxygen (O), has an ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and is an electron There is no particular limitation as long as it has insulating properties.

Specific compounds, for example _Li x _La y TiO ₃ [x = 0.3~0.7, y = 0.3~0.7] _{(LLT), Li x La y} Zr z M m O n (M is at least one element selected from Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In, and Sn, x satisfies 5 ≦ x ≦ 10, and y satisfies 1 ≦ y ≦ 4. Z satisfies 1 ≦ z ≦ 4, m satisfies 0 ≦ m ≦ 2, and n satisfies 5 ≦ n ≦ 20. Li _x B _y M _z O _n (where M is C, S , Al, Si, Ga, Ge, In, Sn, where x satisfies 0 ≦ x ≦ 5, y satisfies 0 ≦ y ≦ 1, and z satisfies 0 ≦ z ≦ 1 , n represents satisfy _{0 ≦ n ≦ 6.),} Li x (Al, Ga) y (Ti, Ge) z Si a P m O n ( however, 1 ≦ x ≦ 3,0 ≦ y ≦ , 0 ≦ z ≦ 2,0 ≦ a ≦ 1,1 ≦ m ≦ 7,3 ≦ n ≦ 13), Li (3-2x) M x DO (x is a number from 0 to 0.1, M Represents a divalent metal atom, D represents a halogen atom or a combination of two or more halogen atoms), Li _x Si _y O _z (1 ≦ x ≦ 5, 0 <y ≦ 3, 1 ≦ z ≦ 10), Li _x S _y O _z (1 ≦ x ≦ 3, 0 <y ≦ 2, 1 ≦ z ≦ 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), LISICON (Lithium super ionic conductor) type crystal structure _Li 3.5 _Zn 0.25 GeO ₄ having, having a perovskite crystal structure _{La 0.55 Li 0.35 TiO 3, NASICON} (Natrium super ionic conductor) type LiTi ₂ P ₃ O ₁₂ having a crystal _{structure, Li (1 + x + y} ) (Al, Ga) x (Ti, Ge) (2-x) Examples include Si _y P _(3-y) O ₁₂ (where 0 ≦ x ≦ 1, 0 ≦ y ≦ 1), Li ₇ La ₃ Zr ₂ O ₁₂ 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 obtained by substituting part of oxygen of lithium phosphate with nitrogen, LiPOD (D is Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb) , Mo, Ru, Ag, Ta, W, Pt, Au, etc.). LiAON (A is at least one selected from Si, B, Ge, Al, C, Ga, etc.) and the like can also be preferably used.
Among _them, Li _x La y TiO ₃ [x = 0.3~0.7, y = 0.3~0.7] _{(LLT), Li x La y} Zr z M m O n (M is Al, Mg , Ca, Sr, V, Nb, Ta, Ti, Ge, In, and Sn, x satisfies 5 ≦ x ≦ 10, y satisfies 1 ≦ y ≦ 4, and z equals 1 ≦ z ≦ 4, m satisfies 0 ≦ m ≦ 2, and n satisfies 5 ≦ n ≦ 20.), Li ₇ La ₃ Zr ₂ O ₁₂ (LLZ), Li ₃ BO ₃ , Li ₃ BO _{3 -Li 2 SO 4, Li x (} Al, Ga) y (Ti, Ge) z Si a P m O n ( however, 1 ≦ x ≦ 3,0 ≦ y ≦ 1,0 ≦ z ≦ 2,0 ≦ a ≦ 1, 1 ≦ m ≦ 7, 3 ≦ n ≦ 13) is preferable. These may be used alone or in combination of two or more.

The ionic conductivity of the lithium ion conductive oxide-based solid electrolyte is preferably 1 × 10 ⁻⁶ S / cm or more, more preferably 5 × 10 ⁻⁶ S / cm or more. It is particularly preferably 10 ⁻⁵ S / cm or more.

In the present invention, the solid electrolyte layer contains a sulfide-based solid electrolyte. Moreover, it is preferable that each layer of a positive electrode active material layer and a negative electrode active material layer contains sulfide type solid electrolyte especially. Sulfide-based solid electrolytes generally have lower hardness than oxide-based solid electrolytes, and therefore, it is less likely to cause an increase in interface resistance in all-solid-state secondary batteries. become.
The said inorganic solid electrolyte may be used individually by 1 type, or may be used in combination of 2 or more type.

  The 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. As an upper limit, it is preferable that it is 100 micrometers or less, and it is more preferable that it is 50 micrometers or less.

The measurement of the average particle diameter of the inorganic solid electrolyte particles is based on the measurement conditions and definitions described below unless otherwise specified.
A 1% by mass dispersion of inorganic solid electrolyte particles is prepared using water (heptane in the case of a substance unstable to water). Using this dispersion liquid sample, the volume average particle diameter of the inorganic solid electrolyte particles is measured using “Laser diffraction / scattering particle size distribution analyzer LA-920” (trade name, manufactured by HORIBA).

The content of the inorganic solid electrolyte in the positive electrode active material layer, solid electrolyte layer, and negative electrode active material layer is the total solid content of each layer when considering both the battery performance and the reduction / maintenance effect of interface resistance. The content is preferably 0% by mass or more, more preferably 1% by mass or more, and particularly preferably 2% by mass or more based on the components. As an upper limit, it is preferable that it is 99.9 mass% or less from the same viewpoint, It is more preferable that it is 99.5 mass% or less, It is especially preferable that it is 99.0 mass% or less. However, when used together with a positive electrode active material or a negative electrode active material, which will be described later, the sum is preferably in the above concentration range.
In the present specification, the solid component refers to a component that does not disappear by volatilization or evaporation when dried at 170 ° C. for 6 hours. Typically, it refers to components other than the dispersion medium described below.

  In the present invention, the solid electrolyte layer contains a sulfide-based solid electrolyte. In the solid electrolyte layer, the ratio of the sulfide-based solid electrolyte to the total solid content is preferably 90% by mass or more, and more preferably 95% by mass or more.

  Moreover, in this invention, content of the inorganic solid electrolyte in at least 1 layer of a positive electrode active material layer and a negative electrode active material layer is 0-10 mass% with respect to the total solid component which comprises each layer, and is 1-10 mass. % Is preferable, and 2 to 10% by mass is more preferable.

(binder)
In the present invention, at least one of the positive electrode active material layer and the negative electrode active material layer contains a binder.
The binder used in the present invention is not particularly limited as long as it is an organic polymer.
The binder that can be used in the present invention is preferably a binder that is usually used as a binder for a positive electrode or a negative electrode of a battery material, and is not particularly limited. The resin constituting the binder is, for example, a fluorine-based resin (for example, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVdF-HFP)), or hydrocarbon-based resin. Resins (eg, polyethylene, polypropylene, styrene butadiene rubber (SBR), hydrogenated styrene butadiene rubber (HSBR), butylene rubber, acrylonitrile butadiene rubber, polybutadiene, polyisoprene), acrylic resins, styrene resins, amide resins, imide resins Examples include resins, urethane resins, urea resins, polyester resins, polyether resins, phenol resins, epoxy resins, polycarbonate resins, silicone resins, or combinations thereof. Among these, acrylic resins and urethane resins are particularly preferable, and urethane resins are most preferable.

  The binder used in the present invention further preferably has a partial structure represented by the following formula (I).

  In formula (I), R represents a hydrogen atom or a monovalent organic group.

  Examples of the polymer having a partial structure represented by the formula (I) include a polymer having an amide bond, a polymer having a urea bond, a polymer having an imide bond, and a polymer having a urethane bond.

  In the present invention, it is preferable that at least one binder contained in at least one of the positive electrode active material layer and the negative electrode active material layer has a partial structure represented by the formula (I). More preferably, all binders contained in the material layer have a partial structure represented by the formula (I).

  Examples of the organic group in R include an alkyl group, an alkenyl group, an aryl group, and a heteroaryl group. R is preferably a hydrogen atom.

-Polymer having amide bond Examples of the polymer having an amide bond include polyamide and polyacrylamide.
Polyamide can be obtained by condensation polymerization of a diamine compound and a dicarboxylic acid compound or ring-opening polymerization of a lactam.
Examples of the diamine compound include ethylenediamine, 1-methylethyldiamine, 1,3-propylenediamine, tetramethylenediamine, pentamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, and undecamethylenediamine. And aliphatic diamine compounds such as dodecamethylenediamine, cyclohexanediamine, bis- (4,4′-aminohexyl) methane, and paraxylylenediamine. Moreover, as a diamine having a polypropyleneoxy chain, for example, a commercially available product “Jeffamine” series (trade name, manufactured by Huntsman, Mitsui Chemicals Fine) can be used. Examples of the “Jeffamine” series include Jeffamine D-230, Jeffamine D-400, Jeffamine D-2000, Jeffamine XTJ-510, Jeffamine XTJ-500, Jeffamine XTJ-501, Jeffamine XTJ-502. , Jeffamine HK-511, Jeffamine EDR-148, Jeffamine XTJ-512, Jeffamine XTJ-542, Jeffamine XTJ-533, Jeffamine XTJ-536, and the like.
Examples of dicarboxylic acid compounds include aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, sebacic acid, pimelic acid, suberic acid, azelaic acid, undecanoic acid, undecadioic acid, dodecadioic acid, and dimer acid, 1,4 -Cyclohexanedicarboxylic acid, paraxylylene dicarboxylic acid, metaxylylene dicarboxylic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid.

  Specific examples of the polyacrylamide include polyethylene glycol monomethyl ether acrylamide, polypropylene glycol monomethyl ether acrylamide, polyethylene glycol monomethyl ether methacrylamide, polypropylene glycol monomethyl ether methacrylamide, polyester methacrylamide, polycarbonate methacrylamide and the like.

-Polymer having a urea bond Polyurea may be mentioned as a polymer having a urea bond. Polyurea can be synthesized by condensation polymerization of a diisocyanate compound and a diamine compound in the presence of an amine catalyst.
Specific examples of the diisocyanate compound are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include 2,4-tolylene diisocyanate, 2,4-tolylene diisocyanate dimer, 2,6- Tolylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, 4,4′-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate, 3,3′-dimethylbiphenyl-4,4′-diisocyanate Aromatic diisocyanate compounds such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, dimer acid diisocyanate; isophorone diisocyanate, 4,4′-methylenebis (Si Cyclohexyl isocyanate), alicyclic diisocyanate compounds such as methylcyclohexane-2,4 (or 2,6) -diyl diisocyanate, 1,3- (isocyanatomethyl) cyclohexane; 1 mol of 1,3-butylene glycol and tolylene diisocyanate And a diisocyanate compound which is a reaction product of diol and diisocyanate such as an adduct of 2 mol. These may be used individually by 1 type and may use 2 or more types together. Among these, 4,4′-diphenylmethane diisocyanate (MDI) and 4,4′-methylenebis (cyclohexyl isocyanate) are preferable.
Specific examples of the diamine compound include the compound examples described above.

-Polymer which has an imide bond As a polymer which has an imide bond, a polyimide is mentioned. A polyimide is obtained by ring-closing after forming a polyamic acid by addition-reacting a tetracarboxylic dianhydride and a diamine compound.
Specific examples of tetracarboxylic dianhydrides include 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (s-BPDA) and pyromellitic dianhydride (PMDA), 2,3,3. ', 4'-biphenyltetracarboxylic dianhydride (a-BPDA), oxydiphthalic dianhydride, diphenylsulfone-3,4,3', 4'-tetracarboxylic dianhydride, bis (3,4- Dicarboxyphenyl) sulfide dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, 2,3,3 ′, 4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis ( 3,4-dicarboki Ciphenyl) propane dianhydride, p-phenylenebis (trimellitic acid monoester anhydride), p-biphenylenebis (trimellitic acid monoester anhydride), m-terphenyl-3,4,3 ′, 4 '-Tetracarboxylic dianhydride, p-terphenyl-3,4,3', 4'-tetracarboxylic dianhydride, 1,3-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,4-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,4-bis (3,4-dicarboxyphenoxy) biphenyl dianhydride, 2,2-bis [(3,4-di Carboxyphenoxy) phenyl] propane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 4,4 ′-(2, 2-F Sa fluoro isopropylidene) diphthalic acid dianhydride, and the like. These may be used alone or in combination of two or more.
The tetracarboxylic acid component preferably includes at least one of s-BPDA and PMDA. For example, s-BPDA is preferably 50 mol% or more, more preferably 70 mol% or more in 100 mol% of the tetracarboxylic acid component, Especially preferably, it contains 75 mol% or more. The tetracarboxylic dianhydride preferably has a rigid benzene ring.

Specific examples of the diamine compound include the compound examples described above.
The diamine compound preferably has a structure having amino groups at both ends of a polyethylene oxide chain, a polypropylene oxide chain, a polycarbonate chain, or a polyester chain.

-Polymer which has a urethane bond As a polymer which has a urethane bond, a polyurethane is mentioned. Polyurethane is obtained by condensation polymerization of a diisocyanate compound and a diol compound in the presence of a titanium, tin, or bismuth catalyst.
Examples of the diisocyanate compound include the compound examples described above.
Specific examples of the diol compound include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, and polyethylene glycol (for example, average molecular weight 200, 400, 600, 1000, 1500, 2000, 3000, 7500 Polyethylene glycol), polypropylene glycol (eg, polypropylene glycol having an average molecular weight of 400, 700, 1000, 2000, 3000, or 4000), neopentyl glycol, 1,3-butylene glycol, 1,4-butanediol, 1,3 -Butanediol, 1,6-hexanediol, 2-butene-1,4-diol, 2,2,4-trimethyl-1,3-pentanediol, 1,4-bis- -Hydroxyethoxycyclohexane, cyclohexanedimethanol, tricyclodecane dimethanol, hydrogenated bisphenol A, hydrogenated bisphenol F, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, ethylene oxide adduct of bisphenol F, bisphenol And propylene oxide adduct of F.

  The diol compound is also available as a commercial product, and examples thereof include polyether diol compounds, polyester diol compounds, polycarbonate diol compounds, polyalkylene diol compounds, and silicone diol compounds.

  The diol compound preferably has at least one of a polyethylene oxide chain, a polypropylene oxide chain, a polycarbonate chain, a polyester chain, a polybutadiene chain, a polyisoprene chain, a polyalkylene chain, and a silicone chain. In addition, the diol compound is a carbon-carbon unsaturated bond or a polar group (alcoholic hydroxyl group, phenolic hydroxyl group, thiol group, carboxyl group, sulfonic acid group from the viewpoint of improving the adsorptivity with a sulfide solid electrolyte or an active material. , Sulfonamide group, phosphoric acid group, nitrile group, amino group, zwitterion-containing group, metal hydroxide, metal alkoxide). As the diol compound, for example, 2,2-bis (hydroxymethyl) propionic acid can be used. As the diol compound containing a carbon-carbon unsaturated bond, the compounds described in Bremer GLM (manufactured by NOF Corporation) and JP-A No. 2007-187836 can be suitably used as commercial products.

  In the case of polyurethane, monoalcohol or monoamine can be used as a polymerization terminator. The polymerization terminator is introduced into the terminal site of the polyurethane main chain. Polyalkylene glycol monoalkyl ether (polyethylene glycol monoalkyl ether and polypropylene monoalkyl ether are preferred), polycarbonate diol monoalkyl ether, polyester diol monoalkyl ether, polyester monoalcohol, etc. Can be used.

  In addition, by using a monoalcohol or monoamine having a polar group or a carbon-carbon unsaturated bond, it is possible to introduce a polar group or a carbon-carbon unsaturated bond at the end of the polyurethane main chain. For example, hydroxyacetic acid, hydroxypropionic acid, 4-hydroxybenzyl alcohol, 3-mercapto-1-propanol, 2,3-dimercapto-1-propanol, 3-mercapto-1-hexanol, 3-hydroxypropanesulfonic acid, 2-cyano Examples include ethanol, 3-hydroxyglutaronitrile, 2-aminoethanol, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, and N-methacrylenediamine.

The binder used in the present invention is preferably polymer particles, and the average particle size of the polymer particles is preferably 0.01 μm to 100 μm, more preferably 0.05 μm to 50 μm, and further preferably 0.05 μm to 20 μm. It is preferable from a viewpoint of an output density improvement that an average particle diameter exists in the said preferable range.
In the present invention, at least one binder contained in at least one of the positive electrode active material layer and the negative electrode active material layer is preferably polymer particles having an average particle diameter of 0.05 μm to 20 μm. It is more preferable that all binders contained in the active material layer are polymer particles having an average particle diameter of 0.05 μm to 20 μm.

Unless otherwise specified, the average particle size of the polymer particles used in the present invention shall be based on the measurement conditions and definitions described below.
Dilute the 1% by weight dispersion of polymer particles in a 20 ml sample bottle using any solvent (dispersion medium used to prepare the solid electrolyte composition, eg, heptane). The diluted dispersion sample is irradiated with 1 kHz ultrasonic waves for 10 minutes and used immediately after that. Using this dispersion sample, using a laser diffraction / scattering particle size distribution measuring device LA-920 (trade name, manufactured by HORIBA), data acquisition was performed 50 times using a quartz cell for measurement at a temperature of 25 ° C. Let the obtained volume average particle diameter be an average particle 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 measured, and the average value is adopted.
In addition, the measurement from the produced all-solid-state secondary battery is performed, for example, after disassembling the battery and peeling off the electrode, then measuring the electrode material according to the measurement method of the average particle diameter of the polymer particles, This can be done by eliminating the measured value of the average particle diameter of the particles other than the polymer particles that have been measured.

  The structure of the polymer particle is not particularly limited as long as it is an organic polymer particle. Examples of the resin constituting the organic polymer particles include the resins described as the resin constituting the binder, and preferred resins are also applied.

  The shape of the polymer particles is not limited as long as the polymer particles are kept solid. The polymer particles may be monodispersed or polydispersed. The polymer particles may be spherical or flat and may be amorphous. The surface of the polymer particles may be smooth or may have an uneven shape. The polymer particles may have a core-shell structure, and the core (inner core) and the shell (outer shell) may be made of the same material or different materials. Moreover, it may be hollow and the hollow ratio is not limited.

The polymer particles can be synthesized by a method of polymerizing in the presence of a surfactant, an emulsifier or a dispersant, or a method of depositing in a crystalline form as the molecular weight increases.
Moreover, you may use the method of crushing the existing polymer mechanically, and the method of making a polymer liquid fine particle by reprecipitation.

  As the polymer particles, for example, commercially available products can be used, and specific examples include the following commercially available products (both are trade names, and the numerical values in parentheses represent the average particle diameter). The polymer particles that can be used in the present invention are not limited to these.

Fluorine-based resin particle microdispers series (manufactured by Techno Chemical Co., Ltd., for example, microdispers-200 (PTFE particles, 200 nm), microdispers-3000 (PTFE particles 3 μm), microdispers-8000 (PTFE) Particles, 8 μm)), Disperse Easy-300 (PTFE particles, 200 nm, manufactured by Techno Chemical Co., Ltd.),
FluonAD series (Asahi Glass Co., Ltd., for example, FluonAD911E, FluonAD915E, FluonAD916E, FluonAD939E),
Algoflon series (manufactured by Solvay Co., Ltd., for example, Algoflon F (PTFE particles, 15 to 35 μm), Algoflon S (PTFE particles, 15 to 35 μm)),
Lubron series (Daikin Co., Ltd., for example, Lubron L-2 (PTFE particles, 3.5 μm), Lubron L-5 (PTFE particles, 5 μm), Lubron L-5F (PTFE particles, 4.5 μm))

・ Hydrocarbon resin particle soft beads, Saixen (polyolefin emulsion), Sepoljon G (polyolefin emulsion), Sepolex IR100 (polyisoprene latex), Sepolex CSM (chlorosulfonated polyethylene latex), Frocene (polyethylene powder), Frocene UF (polyethylene) Powder), flowbrene (polypropylene powder), flow beads (polyethylene-acrylic copolymer powder) (all manufactured by Sumitomo Seika Co., Ltd.)

Acrylic resin particle art pearl series (manufactured by Negami Kogyo Co., Ltd., for example, art pearl GR, art pearl SE, art pearl G, art pearl GR, art pearl GR, art pearl GS, art pearl J, art pearl MF , Art Pearl BE),
Tuftic series (Toyobo Co., Ltd., for example, Tuftic AR-650, Tuftic AR-750, Tuftic FH-S,
Chemisnow series (manufactured by Soken Chemical Co., Ltd., for example, Chemisnow MP-1451, Chemisnow MP-2200, Chemisnow MP-1000, Chemisnow MP-2701, Chemisnow MP-5000, Chemisnow MP-5500, Chemisnow MP-300, Chemisnow KMR-3TA, Chemisnow MX-80H3wT, Chemisnow MX-150, Chemisnow MX-180TA, Chemisnow MX-300, Chemisnow MX-500, Chemisnow MX-500H, Chemisnow MX-1000, Chemisnow MX-1500H, Chemisnow MX-2000, Chemisnow MX-3000,
FS series (Nippon Paint Co., Ltd., for example, FS-101, FS-102, FS-106, FS-107, FS-201, FS-301, FS-501, FS-701),
MG series (manufactured by Nippon Paint Co., Ltd., for example, MG-155E, MG-451, MG-351),
Techpolymer series (manufactured by Sekisui Plastics Co., Ltd., for example, Techpolymer MBX, Techpolymer SBX, Techpolymer MSX, Techpolymer SSX, Techpolymer BMX, Techpolymer ABX, Techpolymer ARX, Techpolymer AFX, Techpolymer MB, Techpolymer MBP), Advancel HB-2051 (manufactured by Sekisui Chemical Co., Ltd.),
Haya beads L-11, Haya beads M-11 (both manufactured by Hayakawa Rubber Co., Ltd.),
Aron T series, Aron A series, Aron SD-10, Aron AC series, Jurimer AC series (all manufactured by Toa Gosei Co., Ltd.),
E poster MA, E poster MX (both made by Nippon Shokubai Co., Ltd.)

  It is also preferable to use the acrylic resin particles described in International Publication No. 2015/046314 as the acrylic resin particles.

Styrene resin particle Chemisnow KSR-3A (manufactured by Soken Chemical Co., Ltd.), Eposta ST (manufactured by Nippon Shokubai Co., Ltd.)

・ Amide resin particles Sephojon PA (copolymer nylon emulsion, manufactured by Sumitomo Seika Co., Ltd.), Trepearl PAI (polyamideimide particles, manufactured by Toray Industries, Inc.)

-Imide resin particle polyimide powder P84 (R) NT (manufactured by Daicel Evonik Co., Ltd.),
Polyimide powder PIP-3, polyimide powder PIP-25, polyimide powder PIP-60 (all manufactured by Seishin Enterprise Co., Ltd.)
Polyimide powder UIP-R, polyimide powder UIP-S (both manufactured by Ube Industries, Ltd.)

-Urethane resin particle dimic beads UCN-8070CM (7 μm), dimic beads UCN-8150CM (15 μm) (both manufactured by Dainichi Seika Co., Ltd.),
Art Pearl Series (Negami Kogyo Co., Ltd., for example, Art Pearl C, Art Pearl P, Art Pearl JB, Art Pearl U, Art Pearl CE, Art Pearl AK, Art Pearl HI, Art Pearl MM, Art Pearl FF, Art Pearl TK, Art Pearl C-TH, Art Pearl RW, Art Pearl RX, Art Pearl RY, Art Pearl RZ, Art Pearl RU, Art Pearl RV, Art Pearl BP),
Grosdale S Series, Grosdale M Series, Grosdale V Series, Grosdale T Series (all manufactured by Mitsui Chemicals)
Infinergy (BASF)

-Urea-based resin particles As the urea-based resin particles, polymer particles having a urea bond described in International Publication No. 2015/046313 are preferably used.

・ Polyester resin particle Sepulsion ES (copolyester emulsion, manufactured by Sumitomo Seika Co., Ltd.)

-Polyether resin particles Trepal PPS (polyphenylene sulfide particles, manufactured by Toray Industries, Inc.), Trepal PES (Polyethersulfone particles, manufactured by Toray Industries, Inc.)

・ Phenolic resin particle LPS series (manufactured by Lignite Co., Ltd.), Marilyn FM series (manufactured by Gunei Chemical Industry Co., Ltd.), Marilyn HF series (manufactured by Gunei Chemical Industry Co., Ltd.)

・ Epoxy resin particles Trepal EP (epoxy resin particles, manufactured by Toray Industries, Inc.)

-Polycarbonate resin particle Polycarbonate resin particle is compoundable by the method as described in international publication 2011/004730 pamphlet, for example. Specifically, it is possible to polymerize by reacting an epoxy compound with carbon dioxide.

・ Silicone resin particle Seahoster KE series (manufactured by Nippon Shokubai Co., Ltd., for example, Seahoster KE-E series, Seahoster KE-W series, Seahoster KE-P series, Seahoster KE-S series),
Silicone composite powder series (for example, silicone composite powder KMP-600, silicone composite powder KMP-601, silicone composite powder KMP-602, silicone composite powder KMP-605, silicone composite powder X-52-7030), silicone resin powder series ( For example, silicone resin powder KMP-590, silicone resin powder KMP-701, silicone resin powder X-52-854, silicone resin powder X-52-1621), silicone rubber powder series (for example, silicone rubber powder KMP-597, silicone Rubber powder KMP-598, silicone rubber powder KMP-594, silicone rubber powder X-52-875 ) Made by the company),
Charine R-170S (silicone acrylic copolymer, manufactured by Nissin Chemical Industry Co., Ltd.)

  The upper limit of the glass transition temperature of the binder is preferably 50 ° C or lower, more preferably 0 ° C or lower, and most preferably -20 ° C or lower. The lower limit is preferably −100 ° C. or higher, more preferably −70 ° C. or higher, and most preferably −50 ° C. or higher.

The glass transition temperature (Tg) is measured under the following conditions using a differential sample using a differential scanning calorimeter “X-DSC7000” (manufactured by SII Nanotechnology Co., Ltd.). The measurement is performed twice on the same sample, and the second measurement result is adopted.
Measurement chamber atmosphere: Nitrogen (50 mL / min)
Temperature increase rate: 5 ° C / min
Measurement start temperature: -100 ° C
Measurement end temperature: 200 ° C
Sample pan: Aluminum pan Mass of measurement sample: 5 mg
Calculation of Tg: Tg is calculated by rounding off the decimal point of the intermediate temperature between the descent start point and descent end point of the DSC chart.

The water concentration of the polymer (preferably polymer particles) constituting the binder used in the present invention is preferably 100 ppm (mass basis) or less, and Tg is preferably 100 ° C. or less.
Moreover, the polymer which comprises the binder used for this invention may be crystallized and dried, and the polymer solution may be used as it is. It is preferable that the amount of metal catalyst (urethane or polyester catalyst, tin, titanium, bismuth catalyst) is small. It is preferable that the metal concentration in the copolymer be 100 ppm (mass basis) or less by reducing the amount during polymerization or removing the catalyst by crystallization.

  The solvent used for the polymerization reaction of the polymer is not particularly limited. It is desirable to use a solvent that does not react with the inorganic solid electrolyte or the active material and that does not decompose them. For example, hydrocarbon solvents (toluene, heptane, xylene), ester solvents (ethyl acetate, propylene glycol monomethyl ether acetate), ether solvents (tetrahydrofuran, dioxane, 1,2-diethoxyethane), ketone solvents (acetone) , Methyl ethyl ketone, cyclohexanone), nitrile solvents (acetonitrile, propionitrile, butyronitrile, isobutyronitrile), halogen solvents (dichloromethane, chloroform) and the like can be used.

The polymer constituting the binder used in the present invention preferably has a mass average molecular weight of 10,000 or more, more preferably 20,000 or more, and even more preferably 50,000 or more. As an upper limit, 1,000,000 or less is preferable, 200,000 or less is more preferable, and 100,000 or less is more preferable.
In the present invention, the molecular weight of the polymer means a mass average molecular weight unless otherwise specified. The mass average molecular weight can be measured as a molecular weight in terms of polystyrene by GPC. At this time, GPC apparatus HLC-8220 (manufactured by Tosoh Corporation) is used, the column is G3000HXL + G2000HXL, the flow rate is 1 mL / min at 23 ° C., and detection is performed by RI. The eluent can be selected from THF (tetrahydrofuran), chloroform, NMP (N-methyl-2-pyrrolidone), m-cresol / chloroform (manufactured by Shonan Wako Pure Chemical Industries, Ltd.) and dissolves. If present, use THF.

The content of the binder in each layer of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer is determined in consideration of the good reduction in the interfacial resistance and the maintainability of the all-solid secondary battery. 0.01 mass% or more is preferable with respect to all the solid components, 0.1 mass% or more is more preferable, and 1 mass% or more is further more preferable. As an upper limit, from a viewpoint of a battery characteristic, 10 mass% or less is preferable, 5 mass% or less is more preferable, and 3 mass% or less is further more preferable.
In the present invention, the mass ratio of the total mass (total amount) of the inorganic solid electrolyte and the electrode active material to be included if necessary relative to the mass of the binder [(mass of inorganic solid electrolyte + mass of electrode active material) / mass of binder] is: A range of 1,000 to 1 is preferred. This mass ratio is more preferably 500 to 2, and more preferably 100 to 10.

  In the present invention, the content of the binder contained in at least one of the positive electrode active material layer and the negative electrode active material layer is preferably 0.01 to 10% by mass with respect to the total solid components of the contained layer, 10 mass% is more preferable, and 1-5 mass% is especially preferable.

(Dispersant)
In the present invention, it is preferable that at least one of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer contains a dispersant. By adding a dispersant, even when the concentration of either the electrode active material or the inorganic solid electrolyte is high, the aggregation can be suppressed, and a uniform electrode layer and solid electrolyte layer can be formed. It is thought to contribute.

The dispersant has a molecular weight of 180 or more and less than 3,000, and has at least one functional group selected from the following functional group group (I), an alkyl group having 8 or more carbon atoms, or an aryl having 10 or more carbon atoms. And a compound having a group.
Functional group (I): acidic group, group having basic nitrogen atom, (meth) acryl group, (meth) acrylamide group, alkoxysilyl group, epoxy group, oxetanyl group, isocyanate group, cyano group, thiol group and hydroxy Group The dispersant used in the present invention may be a compound classified into any of low molecules, oligomers and polymers. In addition, when a dispersing agent is an oligomer and a polymer, molecular weight means a mass average molecular weight, and a mass average molecular weight can be measured by GPC.
Hereinafter, the dispersant will be described in more detail.

  The molecular weight of the dispersant used in the present invention is preferably 200 or more and less than 2,000, more preferably 250 or more and less than 1,500, and even more preferably 250 or more and less than 1,000. When the amount is not more than the above upper limit, aggregation of the electrode active material and the particles of the inorganic solid electrolyte is less likely to occur, and a decrease in output density can be effectively suppressed. Moreover, when it is more than the said lower limit, it becomes easy to volatilize in the step which apply | coats and dries a solid electrolyte composition slurry, and is preferable from a viewpoint of manufacture of the electrode sheet for all-solid-state secondary batteries, and all-solid-state secondary batteries.

In the functional group (I), examples of the acidic group include a carboxy group, a sulfonic acid group, and a phosphoric acid group, and examples of the group having a basic nitrogen atom include an amino group and a pyridyl group.
Of the functional group (I), an acidic group, a group having a basic nitrogen atom, and a cyano group are preferable, and an acidic group is more preferable. Of the acidic groups, a carboxy group is most preferred.

-Alkyl group having 8 or more carbon atoms The alkyl group having 8 or more carbon atoms in the dispersant may be an alkyl group having 8 or more carbon atoms in total, and may be linear, branched or cyclic, Not only when it is a hydrocarbon, but also a bond via a hetero atom may be contained between carbon-carbon bonds. The alkyl group having 8 or more carbon atoms may be unsubstituted, may further have a substituent, and may further have an unsaturated carbon-carbon bond in the middle.

The alkyl group having 8 or more carbon atoms is preferably an alkyl group having 8 to 50 carbon atoms, more preferably an alkyl group having 8 to 30 carbon atoms, still more preferably an alkyl group having 8 to 20 carbon atoms, 8 to 18 alkyl groups are particularly preferred.
Specifically, normal octyl group, normal decyl group, normal dodecyl group, normal tetradecyl group, normal hexadecyl group, stearyl group, lauryl group, linole group, linolene group, 2-ethylhexyl group, 2-ethyloctyl group, Examples include 2-ethyldodecyl group, polyethylene glycol monomethyl group, perfluorooctyl group, perfluorododecyl group and the like.

  Among these, normal octyl group, 2-ethylhexyl group, normal nonyl group, normal decyl group, normal undecyl group, normal dodecyl group, normal tetradecyl group, and normal octadecyl group (stearyl group) are preferable.

When the alkyl group having 8 or more carbon atoms has a substituent, examples of the substituent include aryl groups having 6 or more carbon atoms such as a phenyl group and a naphthyl group, a halogen atom, and the like, and a halogen atom is particularly preferable.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the alkyl group having 8 or more carbon atoms having a substituent include an alkyl group substituted with an aryl group and a halogenated alkyl group substituted with a halogen atom.

-Aryl group having 10 or more carbon atoms The aryl group having 10 or more carbon atoms in the dispersant may be an aryl group having a total carbon number of 10 or more, and is not limited to being a hydrocarbon. It may contain atoms. Further, the aryl group having 10 or more carbon atoms may be unsubstituted or may further have a substituent.

The aryl group having 10 or more carbon atoms is preferably an aryl group having 10 to 50 carbon atoms, more preferably an aryl group having 10 to 30 carbon atoms, still more preferably an aryl group having 10 to 20 carbon atoms, An aryl group of 10 to 18 is particularly preferred.
Specific examples include a naphthyl group, anthracenyl group, pyrenyl group, terphenyl group, naphthacenyl group, pentacenyl group, benzopyrenyl group, chrysenyl group, triphenylenyl group, corannulenyl group, coronenyl group, and obalenyl group.

  Among these, a condensed aromatic hydrocarbon group is preferable.

When the aryl group having 10 or more carbon atoms has a substituent, examples of the substituent include an alkyl group having 8 or more carbon atoms such as a normal octyl group, a halogen atom, and the like, and among them, a halogen atom is preferable.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the aryl group having 10 or more carbon atoms having a substituent include an aryl group substituted with an alkyl group.

  The dispersant is most preferably a compound containing a carboxy group and an alkyl group having 8 or more carbon atoms in the same molecule. Specifically, a long-chain saturated fatty acid (for example, stearic acid), a long-chain immiscible compound. Saturated fatty acids (for example, oleic acid and linolenic acid) can be used more suitably.

  The dispersant used in the present invention is a compound having one or more groups represented by the functional group (I) and two or more alkyl groups having 8 or more carbon atoms or aryl groups having 10 or more carbon atoms. It is more preferable that

  In the present invention, the content of the dispersant contained in at least one of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer is preferably 0.01 to 10% by mass with respect to the total solid components of each layer. 1 to 5% by mass is preferable, and 1 to 3% by mass is more preferable.

(Lithium salt)
In the present invention, it is also preferable that at least one of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer contains a lithium salt.
As a lithium salt, the lithium salt normally used for this kind of product is preferable, and there is no restriction | limiting in particular, For example, what is described below is preferable.

(L-1) Inorganic lithium salts: inorganic fluoride salts such as LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiSbF ₆ ; perhalogenates such as LiClO ₄ , LiBrO ₄ , LiIO ₄ ; inorganic chloride salts such as LiAlCl ₄ etc.

(L-2) Fluorine-containing organic lithium salt: Perfluoroalkane sulfonate such as LiCF ₃ SO ₃ ; LiN (CF ₃ SO ₂ ) ₂ , LiN (CF ₃ CF ₂ SO ₂ ) ₂ , LiN (FSO ₂ ) ₂ , Perfluoroalkanesulfonylimide salts such as LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ); perfluoroalkanesulfonylmethide salts such as LiC (CF ₃ SO ₂ ) ₃ ; Li [PF ₅ (CF ₂ CF ₂ CF ₃ )], Li [PF ₄ (CF ₂ CF ₂ CF ₃ ) ₂ ], Li [PF ₃ (CF ₂ CF ₂ CF ₃ ) ₃ ], Li [PF ₅ (CF ₂ CF ₂ CF ₂ CF _{3 )], Li [PF 4 (} CF 2 CF 2 CF 2 CF 3) 2], Li [PF 3 (CF 2 CF 2 CF 2 CF 3) 3] fluoroalkyl fluoride such as potash Acid salts, and the like.

(L-3) Oxalatoborate salt: lithium bis (oxalato) borate, lithium difluorooxalatoborate and the like.
Among these, LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiSbF ₆ , LiClO ₄ , Li (Rf ¹ SO ₃ ), LiN (Rf ¹ SO ₂ ) ₂ , LiN (FSO ₂ ) ₂ , and LiN (Rf ¹ SO ₂ ) (Rf ² SO ₂ ), preferably LiPF ₆ , LiBF ₄ , LiN (Rf ¹ SO ₂ ) ₂ , LiN (FSO ₂ ) ₂ , and LiN (Rf ¹ SO ₂ ) (Rf ² SO ₂ ) More preferred are imide salts. Here, Rf ¹ and Rf ² each independently represents a perfluoroalkyl group.
In addition, lithium salt may be used individually by 1 type, or may combine 2 or more types arbitrarily.

  The content of the lithium salt is preferably 0 part by mass or more and more preferably 5 parts by mass or more with respect to 100 parts by mass of the solid electrolyte. As an upper limit, 50 mass parts or less are preferable, and 20 mass parts or less are more preferable.

(Electrode active material)
The electrode active material used in the present invention includes a positive electrode active material contained in the positive electrode active material layer and a negative electrode active material contained in the negative electrode active material layer.
(Positive electrode active material)
It is preferable to use a transition metal oxide for the positive electrode active material, and it is preferable to have a transition element M ^a (one or more elements selected from Co, Ni, Fe, Mn, Cu, and V). Further, mixed element M ^b (elements of the first (Ia) group of the metal periodic table other than lithium, elements of the second (IIa) group, Al, Ga, In, Ge, Sn, Pb, Sb, Bi, Si , P, B, etc.) may be mixed.
Transition metal oxides include, for example, specific transition metal oxides including those represented by any of the following formulas (MA) to (MC), or other transition metal oxides such as V ₂ O ₅ and MnO _2. Can be mentioned. As the positive electrode active material, a particulate positive electrode active material may be used.
Specifically, a transition metal oxide capable of reversibly inserting and releasing lithium ions can be used, and the specific transition metal oxide is preferably used.

Transition metal oxides, oxides containing the above transition element M ^a is preferably exemplified. At this time, a mixed element M ^b (preferably Al) or the like may be mixed. The mixing amount is preferably 0 to 30 mol% with respect to the amount of the transition metal. That the molar ratio of li / ^{M a} is synthesized by mixing so that 0.3 to 2.2 is more preferable.

[Transition metal oxide represented by formula (MA) (layered rock salt structure)]
As the lithium-containing transition metal oxide, those represented by the following formula are preferable.

Li _a M ¹ O _b Formula (MA)

Wherein (MA), ^{M 1} are as defined above ^{M a,} and the preferred range is also the same. a represents 0 to 1.2 (preferably 0.2 to 1.2), and preferably 0.6 to 1.1. b represents 1-3 and 2 is preferable. A part of M ¹ may be substituted with the mixed element M ^b .
The transition metal oxide represented by the formula (MA) typically has a layered rock salt structure.

  The transition metal oxide represented by the formula (MA) is more preferably represented by the following formulas.

_{(MA-1) Li g CoO} k
_{(MA-2) Li g NiO} k
_{(MA-3) Li g MnO} k
_{(MA-4) Li g Co} j Ni 1-j O k
_{(MA-5) Li g Ni} j Mn 1-j O k
_{(MA-6) Li g Co} j Ni i Al 1-j-i O k
_{(MA-7) Li g Co} j Ni i Mn 1-j-i O k

Here, g is synonymous with the above-mentioned a, and its preferable range is also the same. j represents 0.1 to 0.9. i represents 0-1. However, 1-j-i is 0 or more. k has the same meaning as b above, and the preferred range is also the same.
Specific examples of these transition metal compounds include LiCoO ₂ (lithium cobaltate [LCO]), LiNi ₂ O ₂ (lithium nickelate), LiNi _0.85 Co _0.10 Al _0.05 O ₂ (nickel cobalt aluminum). Lithium acid [NCA]), LiNi _0.33 Co _0.33 Mn _0.33 O ₂ (nickel manganese lithium cobaltate [NMC]), LiNi _0.5 Mn _0.5 O ₂ (lithium manganese nickelate) It is done.

  The transition metal oxide represented by the formula (MA) partially overlaps, but when represented by changing the notation, those represented by the following are also preferable examples.

_{(I) Li g Ni xc Mn} yc Co zc O 2 (xc> 0.2, yc> 0.2, zc ≧ 0, xc + yc + zc = 1)
Representative:
_{Li g Ni 1/3 Mn 1/3 Co 1/3} O 2
Li _g Ni _1/2 Mn _1/2 O ₂

_{(Ii) Li g Ni xd Co} yd Al zd O 2 (xd> 0.7, yd>0.1,0.1> zd ≧ 0.05, xd + yd + zd = 1)
Representative:
_{Li g Ni 0.8 Co 0.15 Al 0.05} O 2

[Transition metal oxide represented by formula (MB) (spinel structure)]
Among the lithium-containing transition metal oxides, those represented by the following formula (MB) are also preferable.

Li _c M ² ₂ O _d Formula (MB)

Wherein (MB), ^{M 2} are as defined above ^{M a,} and the preferred range is also the same. c represents 0-2, 0.2-2 are preferable and 0.6-1.5 are more preferable. d represents 3-5, and 4 is preferable.

  The transition metal oxide represented by the formula (MB) is more preferably represented by the following formulas.

_{(MB-1) Li m Mn} 2 O n
_{(MB-2) Li m Mn} p Al 2-p O n
_{(MB-3) Li m Mn} p Ni 2-p O n

m is synonymous with c, and its preferable range is also the same. n is synonymous with d, and its preferable range is also the same. p represents 0-2.
Examples of these transition metal oxides include LiMn ₂ O ₄ and LiMn _1.5 Ni _0.5 O ₄ .

  Preferred examples of the transition metal oxide represented by the formula (MB) include those represented by the following formulas.

(A) LiCoMnO ₄
(B) Li ₂ FeMn ₃ O ₈
(C) Li ₂ CuMn ₃ O ₈
(D) Li ₂ CrMn ₃ O ₈
(E) Li ₂ NiMn ₃ O ₈

  Of these, an electrode containing Ni is more preferable from the viewpoint of high capacity and high output.

[Transition metal oxide represented by formula (MC)]
The lithium-containing transition metal oxide is preferably a lithium-containing transition metal phosphate, and among them, one represented by the following formula (MC) is also preferable.

^{_{Li e M 3 (PO 4)}} f ··· formula (MC)

  In formula (MC), e represents 0 to 2 (preferably 0.2 to 2), and preferably 0.5 to 1.5. f represents 1-5, and 1-2 are preferable.

M ³ represents one or more elements selected from the group consisting of V, Ti, Cr, Mn, Fe, Co, Ni, and Cu. M ³ represents, other mixing element ^{M b} above, Ti, Cr, Zn, Zr, may be substituted by other metals such as Nb. Specific examples include, for example, olivine-type iron phosphates such as LiFePO ₄ and Li ₃ Fe ₂ (PO ₄ ) ₃ , iron pyrophosphates such as LiFeP ₂ O ₇ , cobalt phosphates such as LiCoPO ₄ , and Li _3. Monoclinic Nasicon type vanadium phosphate salts such as V ₂ (PO ₄ ) ₃ (lithium vanadium phosphate) can be mentioned.

  The a, c, g, m, and e values representing the composition of Li are values that change due to charge and discharge, and are typically evaluated as values in a stable state when Li is contained. In the formulas (a) to (e), the composition of Li is shown as a specific value, which also changes depending on the operation of the battery.

  The average particle diameter of the positive electrode active material used in the all solid state secondary battery of the present invention is not particularly limited, but is preferably 0.1 μm to 50 μm. In order to make the positive electrode active substance have a predetermined particle size, a normal pulverizer 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 average particle size of the positive electrode active material is measured by the same method as the above-described method for measuring the average particle size of the inorganic solid electrolyte.

  The concentration of the positive electrode active material is not particularly limited. In addition, the content of the positive electrode active material is preferably 20 to 100% by mass, more preferably 40 to 100% by mass, and more preferably 90 to 100% by mass with respect to 100% by mass of the solid component with respect to the total solid components constituting the positive electrode active material layer. 100 mass% is more preferable.

(Negative electrode active material)
As the negative electrode active material, those capable of reversibly inserting and releasing lithium ions are preferable. Such materials are not particularly limited, and are carbonaceous materials, metal oxides such as tin oxide and silicon oxide, metal composite oxides, lithium alloys such as lithium alone and lithium aluminum alloys, and lithium such as Sn and Si. And metals capable of forming an alloy. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and a ratio. Of these, carbonaceous materials or lithium composite oxides are preferably used from the viewpoint of safety. In addition, the metal composite oxide is preferably capable of inserting and extracting lithium. The material is not particularly limited, and preferably 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 made of carbon. Examples thereof include carbonaceous materials obtained by firing artificial graphite such as petroleum pitch, natural graphite, and vapor-grown graphite, and various synthetic resins such as PAN-based resins and furfuryl alcohol resins. Furthermore, various carbon fibers such as PAN-based carbon fiber, cellulose-based carbon fiber, pitch-based carbon fiber, vapor-grown carbon fiber, dehydrated PVA-based carbon fiber, lignin carbon fiber, glassy carbon fiber, activated carbon fiber, mesophase micro Examples thereof include spheres, graphite whiskers, and flat graphite.

  These carbonaceous materials can be divided into non-graphitizable carbon materials and graphite-based carbon materials depending on the degree of graphitization. Further, the carbonaceous material preferably has the surface spacing, density, and crystallite size described in JP-A-62-222066, JP-A-2-6856, and 3-45473. The carbonaceous material does not need to be a single material, and a mixture of natural graphite and artificial graphite described in JP-A-5-90844, graphite having a coating layer described in JP-A-6-4516, and the like. It can also be used.

  As the metal oxide and 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. It is done. The term “amorphous” as used herein means an X-ray diffraction method using CuKα rays, which has a broad scattering band having an apex in the region of 20 ° to 40 ° in terms of 2θ values, and is a crystalline diffraction line. You may have. The strongest intensity of crystalline diffraction lines seen from 2 ° to 40 ° to 70 ° is 100 times the diffraction line intensity at the peak of the broad scattering band seen from 2 ° to 20 °. Is preferably 5 times or less, and more preferably not having a crystalline diffraction line.

Among the group of compounds consisting of the above amorphous oxide and chalcogenide, amorphous metal oxides and chalcogenides are more preferable, and elements in groups 13 (IIIB) to 15 (VB) of the periodic table are preferred. Further preferred are oxides and chalcogenides composed of one kind of Al, Ga, Si, Sn, Ge, Pb, Sb, Bi or a combination of two or more kinds thereof. Specific examples of preferable amorphous oxides and chalcogenides include, for example, Ga ₂ O ₃ , SiO, GeO, SnO, SnO ₂ , PbO, PbO ₂ , Pb ₂ O ₃ , Pb ₂ O ₄ , Pb ₃ O ₄ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅ , Bi ₂ O ₃ , Bi ₂ O ₄ , SnSiO ₃ , GeS, SnS, SnS ₂ , PbS, PbS ₂ , Sb ₂ S ₃ , Sb ₂ S ₅ , such as SnSiS ₃ may preferably be mentioned. Moreover, these may be a complex oxide with lithium oxide, for example, Li ₂ SnO ₂ .

  The average particle diameter of the negative electrode active material is preferably 0.1 μm to 60 μm. In order to obtain a predetermined particle size, a well-known pulverizer or classifier is used. For example, a mortar, a ball mill, a sand mill, a vibrating ball mill, a satellite ball mill, a planetary ball mill, a swirling air flow type jet mill or a sieve is preferably used. When pulverizing, wet pulverization in the presence of water or an organic solvent such as methanol can be performed as necessary. In order to obtain a desired particle size, classification is preferably performed. The classification method is not particularly limited, and a sieve, an air classifier, or the like can be used as necessary. Classification can be used both dry and wet. The average particle diameter of the negative electrode active material particles is measured by the same method as the above-described method for measuring the average particle diameter of the inorganic solid electrolyte particles.

  The composition formula of the compound obtained by the above firing method can be calculated from an inductively coupled plasma (ICP) emission spectroscopic analysis method as a measurement method and a mass difference between powders before and after firing as a simple method.

  Examples of the negative electrode active material that can be used in combination with the amorphous oxide negative electrode active material centering on Sn, Si, and Ge include carbon materials that can occlude and release lithium ions or lithium metal, lithium, lithium alloys, lithium A metal that can be alloyed with is preferable.

In the present invention, the negative electrode active material layer contains a negative electrode active material represented by the following formula (α).
Li _xα M ^α _yα O _zα formula (α)
In the formula (α), M ^α represents an element selected from Al, Ga, In, Ti, Si, Sn, Ge, Pb, Sb, Nb, W, Mo, Fe, and Bi. xα to zα represent the composition ratio of each element, and xα = 0 to 4, yα = 0.3 to 7, and zα = 0.5 to 15.

Examples of such a negative electrode active material include Nb ₂ O ₅ , TiO ₂ , Li ₄ Ti ₅ O ₁₂ [LTO], WO ₂ , MoO ₂ , Fe ₂ O _{3 and the} like.

The negative electrode active material preferably contains a titanium atom. In the present invention, among the negative electrode active materials represented by the above formula (α), lithium titanate (Li ₄ Ti ₅ O ₁₂ [LTO]) is rapid because the volume fluctuation at the time of occlusion and release of lithium ions is small. It is preferable in that the charge / discharge characteristics are excellent, the electrode deterioration is suppressed, and the life of the lithium ion secondary battery can be improved. By combining a specific negative electrode and a specific electrolyte, the stability of the secondary battery is improved even under various usage conditions.

  In the all solid state secondary battery of the present invention, it is also preferable to apply a negative electrode active material containing Si element. In general, a Si negative electrode can occlude more Li ions than current carbon negative electrodes (graphite, acetylene black, etc.). That is, since the amount of Li ion storage per mass increases, the battery capacity can be increased. As a result, there is an advantage that the battery driving time can be extended, and use in a battery for vehicles is expected in the future.

  The concentration of the negative electrode active material is not particularly limited. In addition, 20-100 mass% is preferable with respect to the total solid component which comprises a negative electrode active material layer, content of a negative electrode active material has more preferable 40-100 mass%, and 90-100 mass% is further more preferable.

  In the present invention, the content of the electrode active material contained in at least one of the positive electrode active material layer and the negative electrode active material layer is preferably 90% by mass or more based on the total solid content constituting each layer. As for content of the electrode active material contained in a material layer and a negative electrode active material layer, it is more preferable that all are 90 mass% or more with respect to the total solid which comprises each layer.

(Dispersion medium)
In the present invention, the solid electrolyte composition used as a molding material for each layer may contain a dispersion medium in which the above components are dispersed. Specific examples of the dispersion medium include the following solvents.
Examples of the alcohol compound solvent include methyl alcohol, ethyl alcohol, 1-propyl alcohol, 2-propyl alcohol, 2-butanol, ethylene glycol, propylene glycol, glycerin, 1,6-hexanediol, cyclohexanediol, sorbitol, xylitol, 2 -Methyl-2,4-pentanediol, 1,3-butanediol, 1,4-butanediol.

  Examples of the ether compound solvent include alkylene glycol alkyl ether (ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol, dipropylene glycol, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol, polyethylene glycol, propylene glycol monomethyl ether, diethylene glycol, Propylene glycol monomethyl ether, tripropylene glycol monomethyl ether, diethylene glycol monobutyl ether, etc.), dimethyl ether, diethyl ether, tetrahydrofuran, cyclopentyl methyl ether, dimethoxyethane, and 1,4-dioxane.

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

  Examples of the ketone compound solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, diisopropyl ketone, diisobutyl ketone, and cyclohexanone.

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

  Examples of the aliphatic compound solvent include hexane, heptane, octane, decane, and dodecane.

  Examples of the nitrile compound solvent include acetonitrile, propionitrile, butyronitrile, isobutyronitrile, and benzonitrile.

  In the present invention, it is also preferable to form a solid electrolyte layer by wet-coating a slurry in which a sulfide-based solid electrolyte is dispersed in a non-aqueous dispersion medium. Examples of the non-aqueous dispersion medium include the above aromatic compound solvents and aliphatic compound solvents.

<Current collector (metal foil)>
The positive and negative current collectors are preferably electron conductors that do not cause chemical changes. The positive electrode current collector is preferably made by treating the surface of aluminum or stainless steel with carbon, nickel, titanium or silver in addition to aluminum, stainless steel, nickel, titanium, etc. Among them, aluminum and aluminum alloys are more preferable. preferable. The current collector of the negative electrode is preferably aluminum, copper, stainless steel, nickel, or titanium, and more preferably aluminum, copper, or a copper alloy.

The current collector is usually in the form of a film sheet, but a net, a punched one, a lath, a porous body, a foam, a fiber group molded body, or the like can also be used.
Although the thickness of a collector is not specifically limited, 1 micrometer-500 micrometers are preferable. Moreover, it is also preferable that the current collector surface is roughened by surface treatment.

<Preparation of all-solid secondary battery>
The all-solid-state secondary battery may be manufactured by a conventional method. Specifically, the composition for an electrode active material layer of the present invention (a composition for a positive electrode active material layer, a composition for a negative electrode active material layer) was applied onto a metal foil serving as a current collector to form a coating film. The method of setting it as the electrode sheet for all-solid-state secondary batteries is mentioned.
For example, a composition (a composition for a positive electrode active material layer) serving as a positive electrode material is applied onto a metal foil that is a positive electrode current collector, a positive electrode active material layer is formed, and a positive electrode sheet for a battery is produced. A solid electrolyte composition is applied on the positive electrode active material layer to form a solid electrolyte layer. Furthermore, on the solid electrolyte layer, a composition (a composition for a negative electrode active material layer) to be a negative electrode material is applied to form a negative electrode active material layer. It is possible to obtain a structure of an all-solid-state secondary battery in which a solid electrolyte layer is sandwiched between a positive electrode layer and a negative electrode layer by overlapping a negative electrode side current collector (metal foil) on the negative electrode active material layer. it can.

  In addition, the application | coating method of said each composition should just follow a conventional method. At this time, the composition for forming the positive electrode active material layer, the composition for forming the inorganic solid electrolyte layer, and the composition for forming the negative electrode active material layer may be subjected to a drying treatment after being applied. Alternatively, after the multilayer coating, a drying process may be performed. The drying temperature is not particularly limited. The lower limit is preferably 30 ° C or higher, more preferably 60 ° C or higher, and the upper limit is preferably 300 ° C or lower, more preferably 250 ° C or lower. By heating in such a temperature range, a dispersion medium can be removed and it can be set as a solid state.

<Uses of all-solid-state secondary batteries>
The all solid state secondary battery of the present invention can be applied to various uses. Although there is no particular limitation on the application mode, for example, when installed in an electronic device, a notebook computer, pen input personal computer, mobile personal computer, electronic book player, mobile phone, cordless phone, pager, handy terminal, mobile fax, mobile phone Copy, portable printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, minidisc, electric shaver, transceiver, electronic notebook, calculator, memory card, portable tape recorder, radio, backup power supply, memory card, etc. It is done. Other consumer products include automobiles, electric vehicles, motors, lighting equipment, toys, game equipment, road conditioners, watches, strobes, cameras, medical equipment (such as pacemakers, hearing aids, and shoulder grinders). Furthermore, it can be used for various military use and space use. Moreover, it can also combine with a solar cell.

  In particular, it is preferable to apply to applications that require high capacity and high rate discharge characteristics. For example, in power storage facilities and the like that are expected to increase in capacity in the future, high safety is essential, and further compatibility of battery performance is required. In addition, electric vehicles and the like are equipped with a high-capacity secondary battery and are expected to be charged every day at home, and further safety is required against overcharging. According to the present invention, it is possible to exhibit the excellent effect correspondingly to such a usage pattern.

According to a preferred embodiment of the present invention, for example, the following applications are derived.
[1] An all-solid secondary battery in which at least one of a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer contains a lithium salt.
[2] A method for producing an all-solid-state secondary battery in which a solid electrolyte layer is wet-coated with a slurry in which a sulfide-based solid electrolyte is dispersed in a non-aqueous dispersion medium.
[3] A composition for an electrode active material layer for producing the all-solid secondary battery.
[4] An electrode sheet for an all-solid-state secondary battery obtained by applying the composition for an electrode active material layer on a metal foil and forming a film.
[5] A method for producing an electrode sheet for an all-solid-state secondary battery, wherein the composition for electrode active material layer is applied onto a metal foil to form a film.
Examples of the method for applying the electrode active material layer composition on the metal foil include coating (wet coating, spray coating, spin coating coating, slit coating, stripe coating, bar coating coating dip coating), Wet coating is preferred.

  As described in [2] and [5] of the preferred embodiments, both the all-solid-state secondary battery and the method for producing the all-solid-state secondary battery electrode sheet of the present invention are wet processes. As a result, even in a region where the content of the inorganic solid electrolyte in at least one of the positive electrode active material layer and the negative electrode active material layer is as low as 10% by mass or less, the adhesion between the active material and the solid electrolyte is increased and an efficient ion conduction path is achieved. An all-solid-state secondary battery that can be maintained and has high energy density (Wh / kg) and high power density (W / kg) per weight of the battery can be manufactured.

An all-solid secondary battery refers to a secondary battery in which the positive electrode, the negative electrode, and the electrolyte are all solid. In other words, it is distinguished from an electrolyte type secondary battery using a carbonate-based solvent as an electrolyte. In this, this invention presupposes an inorganic all-solid-state secondary battery. The all-solid-state secondary battery includes an organic (polymer) all-solid-state secondary battery that uses a polymer compound such as polyethylene oxide as an electrolyte, and an inorganic all-solid-state that uses the above Li-PS-based glass, LLT, LLZ, or the like. It is divided into secondary batteries. Note that the application of the polymer compound to the inorganic all-solid secondary battery is not hindered, and the polymer compound can be applied as a binder for the positive electrode active material, the negative electrode active material, and the inorganic solid electrolyte.
The inorganic solid electrolyte is distinguished from an electrolyte (polymer electrolyte) using the above-described polymer compound as an ion conductive medium, and the inorganic compound serves as an ion conductive medium. Specific examples include Li-PS-based glass, LLT, and LLZ. The inorganic solid electrolyte itself does not release cations (Li ions) but exhibits an ion transport function. On the other hand, a material that is added to the electrolytic solution or the solid electrolyte layer and serves as a source of ions that release cations (Li ions) is sometimes called an electrolyte. When distinguishing from the electrolyte as the above ion transport material, this is called “electrolyte salt” or “supporting electrolyte”. An example of the electrolyte salt is LiTFSI.
In the present invention, the “composition” means a mixture in which two or more components are uniformly mixed. However, as long as the uniformity is substantially maintained, aggregation or uneven distribution may partially occur within a range in which a desired effect is achieved.

  Below, based on an Example, it demonstrates still in detail about this invention. The present invention is not construed as being limited thereby. In the following examples, “parts” and “%” are based on mass unless otherwise specified.

<Synthesis of sulfide-based inorganic solid electrolyte>
-Synthesis of Li-PS-S glass-
As a sulfide-based inorganic solid electrolyte, T.I. Ohtomo, A .; Hayashi, M .; Tatsumisago, Y. et al. Tsuchida, S .; Hama, K .; Kawamoto, Journal of Power Sources, 233, (2013), pp231-235 and A.K. Hayashi, S .; Hama, H .; Morimoto, M .; Tatsumisago, T .; Minami, Chem. Lett. , (2001), pp 872-873, Li-PS glass was synthesized with reference to non-patent literature.

Specifically, in a glove box under an argon atmosphere (dew point −70 ° C.), 2.42 g of lithium sulfide (Li ₂ S, manufactured by Aldrich, purity> 99.98%) and diphosphorus pentasulfide (P ₂ S ₅ , 3.90 g manufactured by Aldrich, purity> 99%) was weighed, put into an agate mortar, and mixed for 5 minutes using an agate pestle. Note that the mixing ratio of Li ₂ S and P ₂ S ₅ was set to Li ₂ S: P ₂ S ₅ = 75: 25 in terms of molar ratio.
Into a 45 mL zirconia container (manufactured by Fritsch), 66 zirconia beads having a diameter of 5 mm were charged, and then the entire amount of the mixture of lithium sulfide and diphosphorus pentasulfide was charged, and the container was completely sealed under an argon atmosphere. . This container is set on a planetary ball mill P-7 (manufactured by Fritsch), mechanical milling is performed at a temperature of 25 ° C. and a rotation speed of 510 rpm for 20 hours, and yellow powder Li—PS glass (sulfide-based inorganic solid electrolyte) 6.20 g was obtained.

Example 1
-Preparation of solid electrolyte composition-
(1) Preparation of Solid Electrolyte Composition (K-1) 180 zirconia beads having a diameter of 5 mm were placed in a 45 mL container (manufactured by Fritsch) made of zirconia, 9.5 g of Li-PS-based glass, PVdF-HFP (Polyvinylidene fluoride-hexafluoropropylene copolymer) 0.5 g and 1,4-dioxane 15.0 g as a dispersion medium were added. Thereafter, this container was set in a planetary ball mill P-7 (manufactured by Fritsch), and stirring was continued for 2 hours at a temperature of 25 ° C. and a rotation speed of 300 rpm to prepare a solid electrolyte composition (K-1).

(2) Preparation of solid electrolyte compositions (K-2) to (K-6) and (HK-1) In preparation of the solid electrolyte composition (K-1), the composition was changed as shown in Table 1. Otherwise, solid electrolyte compositions (K-2) to (K-6) and (HK-1) were prepared in the same manner as in the solid electrolyte composition (K-1).

<Table notes>
LLT: Li _0.33 La _0.55 TiO ₃ (average particle size 3.25 μm)
Li-PS: Li-PS-based glass synthesized above B-1: PVdF-HFP (polyvinylidene fluoride-hexafluoropropylene copolymer) Arkema Co., Ltd. mass average molecular weight 100,000 B-2: SBR (styrene butadiene rubber) manufactured by Aldrich Co., Ltd. Mass average molecular weight 150,000 / B-3: Acrylic polymer (methyl methacrylate-butyl acrylate copolymer) (radical polymer, initiator: V -601 (manufactured by Wako Pure Chemical Industries, Ltd.), monomer composition ratio: 70 mol% methyl methacrylate, 30 mol% butyl acrylate)
B-4: Urethane polymer (copolymer of methylenebis (cyclohexyl isocyanate) -butanediol-polyethylene glycol 1000) (polycondensation product, initiator: Neostan U-600 (manufactured by Nitto Kasei Co., Ltd.)), monomer composition ratio : Methylene bis (cyclohexyl isocyanate) 50 mol%, butanediol 25 mol%, polyethylene glycol 1000 25 mol%)
B-5: Acrylic resin fine particles: Techpolymer MBX-5 (trade name, average particle diameter of 5 μm, manufactured by Sekisui Plastics Co., Ltd.)
B-6: Urethane resin fine particles: Dimic beads UCN-8070CM (trade name, average particle diameter 7 μm, manufactured by Dainichi Seika Co., Ltd.)

-Preparation of composition for positive electrode of secondary battery-
(1) Preparation of composition for positive electrode (U-1) 180 zirconia beads having a diameter of 5 mm were put into a 45 mL container (manufactured by Fritsch) made of zirconia, and an inorganic solid electrolyte LLZ (Li ₇ La ₃ Zr ₂ O ₁₂ , An average particle size of 5.06 μm, manufactured by Toshima Seisakusho Co., Ltd. 0.5 g, PVdF-HFP (polyvinylidene fluoride-hexafluoropropylene copolymer) 0.5 g, and 1,4-dioxane 12.3 g as a dispersion medium. I put it in. This container was set in a planetary ball mill P-7 (manufactured by Fritsch), and machine dispersion was continued for 2 hours under the conditions of a temperature of 25 ° C. and a rotation speed of 300 rpm. Thereafter, 9.0 g of lithium cobalt oxide (LCO, manufactured by Nippon Kagaku Kogyo Co., Ltd.) as an active material is put into the container, and the container is set again on the planetary ball mill P-7, at a temperature of 25 ° C. and a rotation speed of 100 rpm. Mixing continued for 15 minutes. In this way, a positive electrode composition (U-1) was prepared.

(2) Preparation of composition for positive electrode (U-2) to (U-6), (HU-1) and (HU-2) In preparation of composition for positive electrode (U-1), the composition is shown in Table 2. Except having changed as shown, it is the same as the positive electrode composition (U-1), and the positive electrode compositions (U-2) to (U-6), (HU-1), and (HU-2). Was prepared. The positive electrode compositions (U-1) to (U-6) are examples of positive electrode compositions, and the positive electrode compositions (HU-1) to (HU-2) are for comparative positive electrodes. It is a composition.

<Table notes>
LLZ: Li ₇ La ₃ Zr ₂ O ₁₂ (average particle diameter 5.06 μm, manufactured by Toshima Seisakusho)
The following are abbreviations for active materials.
LCO: LiCoO ₂ lithium cobaltate NMC: Li (Ni _1/3 Mn _1/3 Co _1/3 ) O ₂ nickel, manganese, lithium cobaltate NCA: LiNi _0.85 Co _0.10 Al _0.05 O ₂ nickel , Cobalt, lithium aluminate

-Preparation of secondary battery negative electrode composition-
(1) Preparation of composition for negative electrode (S-1) In a zirconia 45 mL container (manufactured by Fritsch), 180 pieces of zirconia beads having a diameter of 5 mm were charged, and 0.9 g of the Li—PS system glass synthesized above. PVdF-HFP (polyvinylidene fluoride-hexafluoropropylene copolymer) (0.1 g) and toluene (12.3 g) as a dispersion medium were added. This container was set in a planetary ball mill P-7 (manufactured by Fritsch), and mechanical dispersion was continued for 2 hours at a temperature of 25 ° C. and a rotation speed of 300 rpm. Thereafter, 9.0 g of lithium titanate (LTO, manufactured by Ishihara Sangyo Co., Ltd.) as an active material was put into the container, and this container was set again on the planetary ball mill P-7. Mixing continued for a minute. In this way, a negative electrode composition (S-1) was prepared.

(2) Preparation of negative electrode compositions (S-2) to (S-5) and (HS-1) In preparation of the negative electrode composition (S-1), the composition was changed as shown in Table 3. Except for the above, negative electrode compositions (S-2) to (S-5) and (HS-1) were prepared in the same manner as the negative electrode composition (S-1). In addition, the composition for negative electrodes (S-1) to (S-5) is a composition for negative electrode serving as an example, and the composition for negative electrode (HS-1) is a composition for negative electrode for comparison.

<Table notes>
The following are abbreviations for active materials: AB: acetylene black, LTO: Li ₄ Ti ₅ O ₁₂ lithium titanate (trade name “Enamite LT-106”, manufactured by Ishihara Sangyo Co., Ltd.)
C-1: Dispersant having the following structure (molecular weight 1335.7)

-Production of positive electrode sheet for secondary battery-
The secondary battery positive electrode composition (U-1) prepared above was applied onto an aluminum foil (current collector) having a thickness of 20 μm with an applicator capable of adjusting the clearance, heated at 80 ° C. for 1 hour, and further The dispersion medium was dried by heating at 110 ° C. for 1 hour. Then, using a heat press machine, it heated and pressurized so that it might become arbitrary density, and manufactured the positive electrode sheet for secondary batteries of thickness 150micrometer which has the laminated structure of a positive electrode active material layer / aluminum foil.

-Manufacture of electrode sheets for all-solid-state secondary batteries-
On the positive electrode active material layer of the positive electrode sheet for a secondary battery produced above, the solid electrolyte composition (K-1) prepared above is applied with an applicator with adjustable clearance, and heated at 80 ° C. for 1 hour. Then, it was further heated at 110 ° C. for 1 hour to form a solid electrolyte layer having a thickness of 10 μm. Thereafter, the secondary battery negative electrode composition (S-1) prepared above was further applied onto the dried solid electrolyte layer, heated at 80 ° C. for 1 hour, and further heated at 110 ° C. for 1 hour to obtain a thickness. A 100 μm negative electrode active material layer was formed. A 20 μm thick copper foil (current collector on the negative electrode side) is placed on the negative electrode active material layer, and heated and heated using a heat press so that the solid electrolyte layer and the negative electrode active material layer have an arbitrary density. Test No. shown in Table 4 below. 101, an electrode sheet for an all-solid-state secondary battery was produced.
Test No. In the production of the electrode sheet for an all-solid-state secondary battery of No. 101, Test No. In the same manner as the electrode sheet for an all-solid-state secondary battery of No. 101, the test No. Electrode sheets for all-solid-state secondary batteries of 102 to 106 and c11 to c12 were produced.
The layer structure of the electrode sheet for an all-solid-state secondary battery is shown in FIG. The electrode sheet for an all-solid secondary battery has a laminated structure of copper foil / negative electrode active material layer / solid electrolyte layer / secondary battery positive electrode sheet (positive electrode active material layer / aluminum foil).

-Manufacture of all-solid-state secondary batteries-
The electrode sheet for the all-solid-state secondary battery produced above is cut into a disk shape having a diameter of 14.5 mm, and is placed in a stainless steel 2032 type coin case 14 incorporating a spacer and a washer as shown in FIG. Tighten with a wrench with a force of 8 Newton meters (N · m) and test No. in Table 4 below. 101 to 106 and c11 to c12 all solid state secondary batteries were manufactured.

<Evaluation>
Test No. manufactured above. The following evaluation was performed on the all-solid secondary batteries 101 to 106 and c11 to c12. The evaluation results are shown in Table 4 below.

<Evaluation of power density per battery weight>
The all-solid-state secondary battery produced above was measured at a temperature of 30 ° C. using a charge / discharge evaluation apparatus “TOSCAT-3000” (trade name) manufactured by Toyo System Co., Ltd.
Charging was performed at a current value of 0.05 mA until the battery voltage reached 3.8 V, and discharging was performed at 0.05 mA for 10 seconds, and the voltage value at that time was read. Charge again to 3.8V with the same amount of current. This was performed at each current amount of 0.1 mA, 0.2 mA, and 0.5 mA, and obtained by extrapolating the current amount when the voltage was 2.5 V after 10 seconds of discharge. The power density per battery weight was calculated from (2.5 V) × (current amount obtained by extrapolation) / (battery weight), and evaluated according to the following criteria. In addition, evaluation "C" or more is a pass level of this test. In Table 4 below, the power density per battery weight is described as “power density”.

(Evaluation criteria)
A: 80 W / kg or more B: 50 W / kg or more and less than 80 W / kg C: 20 W / kg or more and less than 50 W / kg D: Less than 20 W / kg

<Evaluation of energy density per battery weight>
The all-solid-state secondary battery produced above was measured at a temperature of 30 ° C. using a charge / discharge evaluation apparatus “TOSCAT-3000” (trade name) manufactured by Toyo System Co., Ltd.
Charging was performed at a current value of 0.2 mA until the battery voltage reached 4.2 V, and discharging was performed at a current value of 0.2 mA until the battery voltage reached 3.0 V. The same charge / discharge was repeated, and the discharge capacity at the third cycle was defined as the battery discharge capacity. The discharge energy (Wh) was calculated by adding the product of the average voltage (V) per 10 seconds during discharge and the average discharge capacity (Ah) until the discharge was completed. By dividing the obtained discharge energy by the battery weight, the energy density (Wh / kg) was determined and evaluated according to the following criteria.
In addition, evaluation "C" or more is a pass level of this test. In Table 4 below, the energy density per weight of the battery is described as “energy density”.

(Evaluation criteria)
A: 20 Wh / kg or more B: 10 Wh / kg or more and less than 20 Wh / kg C: 5 Wh / kg or more and less than 10 Wh / kg D: Less than 5 Wh / kg

<Evaluation of cycle characteristics>
The cycle characteristics of the all-solid-state secondary battery produced above were measured at a temperature of 30 ° C. using a charge / discharge evaluation apparatus “TOSCAT-3000” (trade name) manufactured by Toyo System Co., Ltd.
Charging / discharging was performed similarly to the calculation of the discharge capacity. The discharge capacity at the third cycle was set to 100, and the following criteria were evaluated from the number of cycles when the discharge capacity was less than 80. In addition, evaluation "B" or more is a pass level of this test.

(Evaluation criteria)
A: 50 times or more B: 40 times or more and less than 50 times C: 30 times or more and less than 40 times D: Less than 30 times

As apparent from Table 4, the test No. having a configuration satisfying the requirements of the present invention. It can be seen that the all-solid secondary batteries 103 to 106 have high output density and energy density per battery weight and excellent cycle characteristics.
On the other hand, the content of the inorganic solid electrolyte in the positive electrode active material layer and the negative electrode active material layer both exceeds 10% by mass, and the negative electrode active material contained in the negative electrode active material layer is not represented by the formula (α). No. The all solid secondary battery of c11, and the content of the inorganic solid electrolyte in the positive electrode active material layer and the negative electrode active material layer both exceed 10% by mass, the solid electrolyte layer does not contain a sulfide solid electrolyte, and the negative electrode Test No. in which the negative electrode active material contained in the active material layer is not represented by the formula (α). All the c12 all-solid-state secondary batteries had low power density and energy density per battery weight, and were not excellent in cycle characteristics.

DESCRIPTION OF SYMBOLS 1 Negative electrode collector 2 Negative electrode active material layer 3 Solid electrolyte layer 4 Positive electrode active material layer 5 Positive electrode collector 6 Working part 10 All-solid secondary battery 11 Upper support plate 12 Lower support plate 13 Coin battery 14 Coin case 15 All solid Secondary battery electrode sheet S Screw

Claims (9)

An all-solid secondary battery having a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order,
In at least one of the positive electrode active material layer and the negative electrode active material layer, the content of the inorganic solid electrolyte in the total solid content of the layer is 0 to 10% by mass,
At least one of the positive electrode active material layer and the negative electrode active material layer in which the content of the inorganic solid electrolyte in the total solid content is 0 to 10% by mass is the electrode active material in the total solid content of the layer. The content is 90% by mass or more,
The solid electrolyte layer contains a sulfide-based solid electrolyte, and the content of the sulfide-based solid electrolyte is 90% by mass or more in the total solid content constituting the solid electrolyte layer,
At least one of the positive electrode active material layer and the negative electrode active material layer contains a binder,
The negative electrode active material layer contains a negative electrode active material represented by the following formula (α), and
Of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer, at least one layer including the solid electrolyte layer contains a dispersant,
The dispersant has a molecular weight of 180 or more and less than 3,000, and at least one functional group selected from the following functional group group (I), an alkyl group having 8 to 30 carbon atoms, or 10 or more carbon atoms An all-solid secondary battery, which is a compound having 30 or less aryl groups.
Li _xα M ^α _yα O _zα formula (α)
In the formula (α), M ^α represents an element selected from Al, Ga, In, Ti, Si, Sn, Ge, Pb, Sb, Nb, W, Mo, Fe, and Bi. xα to zα represent the composition ratio of each element, and xα = 0 to 4, yα = 0.3 to 7, and zα = 0.5 to 15.
Functional group (I): an acidic group, a group having a basic nitrogen atom, and a cyano group. The all-solid-state secondary battery according to claim 1 , wherein the negative electrode active material is Li ₄ Ti ₅ O ₁₂ . The positive active material layer, at least one layer thickness of the solid electrolyte layer and the anode active material layer, all-solid secondary battery according to claim 1 or 2 or more and less than 50 [mu] m 500 [mu] m. At least one kind, all-solid secondary battery according to any one of claims 1 to 3 which is a polymer particle having an average particle diameter 0.05μm~20μm of the binder. The all-solid-state secondary battery according to any one of claims 1 to 4 , wherein at least one of the binders has a partial structure represented by the following formula (I).

In formula (I), R represents a hydrogen atom or a monovalent organic group. The production of the all-solid-state secondary battery according to any one of claims 1 to 5 , wherein the solid electrolyte layer is wet-coated with a slurry in which the sulfide-based solid electrolyte is dispersed by a non-aqueous dispersion medium to form a film. Method. It is a composition for electrode active material layers which forms the positive electrode active material layer or negative electrode active material layer of the all-solid-state secondary battery of any one of Claims 1-5 ,
The electrode active material layer composition is:
Content of inorganic solid electrolyte is 0-10 mass% in the total solid which comprises the said composition for electrode active material layers, contains an electrode active material, a binder, and a dispersing agent, Content of this electrode active material Is 90% by mass or more in the total solid content constituting the composition for an electrode active material layer,
The electrode active material contained in the composition for electrode active material layer forming the negative electrode active material layer is a negative electrode active material represented by the following formula (α),
The dispersant has a molecular weight of 180 or more and less than 3,000, and at least one functional group selected from the following functional group group (I), an alkyl group having 8 to 30 carbon atoms, or 10 or more carbon atoms The composition for electrode active material layers which is a compound which has 30 or less aryl groups.
Li _xα M ^α _yα O _zα formula (α)
In the formula (α), M ^α represents an element selected from Al, Ga, In, Ti, Si, Sn, Ge, Pb, Sb, Nb, W, Mo, Fe, and Bi. xα to zα represent the composition ratio of each element, and xα = 0 to 4, yα = 0.3 to 7, and zα = 0.5 to 15.
Functional group (I): an acidic group, a group having a basic nitrogen atom, and a cyano group. The manufacturing method of the electrode sheet for all-solid-state secondary batteries which applies the composition for electrode active material layers of Claim 7 on metal foil, and forms into a film. An electrode sheet for an all-solid secondary battery having a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order,
In at least one of the positive electrode active material layer and the negative electrode active material layer, the content of the inorganic solid electrolyte in the total solid content of the layer is 0 to 10% by mass,
At least one of the positive electrode active material layer and the negative electrode active material layer in which the content of the inorganic solid electrolyte in the total solid content is 0 to 10% by mass is the electrode active material in the total solid content of the layer. The content is 90% by mass or more,
The solid electrolyte layer contains a sulfide-based solid electrolyte, and the content of the sulfide-based solid electrolyte is 90% by mass or more in the total solid content constituting the solid electrolyte layer,
At least one of the positive electrode active material layer and the negative electrode active material layer contains a binder,
The negative electrode active material layer contains a negative electrode active material represented by the following formula (α), and
Of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer, at least one layer including the solid electrolyte layer contains a dispersant,
The dispersant has a molecular weight of 180 or more and less than 3,000, and at least one functional group selected from the following functional group group (I), an alkyl group having 8 to 30 carbon atoms, or 10 or more carbon atoms An electrode sheet for an all-solid-state secondary battery, which is a compound having 30 or less aryl groups.
Li _xα M ^α _yα O _zα formula (α)
In the formula (α), M ^α represents an element selected from Al, Ga, In, Ti, Si, Sn, Ge, Pb, Sb, Nb, W, Mo, Fe, and Bi. xα to zα represent the composition ratio of each element, and xα = 0 to 4, yα = 0.3 to 7, and zα = 0.5 to 15.
Functional group (I): an acidic group, a group having a basic nitrogen atom, and a cyano group.

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