JP6572063B2 - All-solid-state secondary battery, electrode sheet for all-solid-state secondary battery, and production method thereof - Google Patents

Description

  The present invention relates to an all-solid secondary battery and a method for manufacturing the same. Moreover, this invention relates to the electrode sheet for all-solid-state secondary batteries, and its manufacturing method.

A lithium ion secondary battery is a storage battery that has a negative electrode, a positive electrode, and an electrolyte sandwiched between the negative electrode and the positive electrode, and can be charged and discharged by reciprocating lithium ions between the two electrodes. . Conventionally, an organic electrolytic solution has been used as an electrolyte in a lithium ion secondary battery. However, organic electrolytes are liable to leak, and overcharge and overdischarge can cause a short circuit inside the battery, resulting in fire, and further improvements in reliability and safety are required.
In order to satisfy such a requirement, it is known that a polymer is blended in an electrolytic solution and an organic electrolytic solution is retained in the polymer. For example, in Patent Document 1, a sheet is prepared using a suspension in which a polymer material such as polyvinylidene fluoride, hexafluoropropylene, and lithium ion conductive glass ceramics are added to acetone. It is described that a sheet-like composite electrolyte made of a gel-like material was created by immersing in an organic solvent such as dimethyl carbonate. By using this composite electrolyte, the battery capacity is high, the charge / discharge cycle characteristics are also good, and the long-term It is described that a lithium secondary battery that can be used stably is obtained.

However, even in the gel electrolyte described in Patent Document 1, a flammable material such as a carbonate-based solvent is used, and it cannot be said that there is no possibility of causing a problem at the time of overcharge, and further improvement in safety. Is desired.
Under such circumstances, an all-solid secondary battery using a non-flammable inorganic solid electrolyte instead of a flammable organic electrolyte has attracted attention. The all-solid-state secondary battery consists of a solid negative electrode, electrolyte, and positive electrode, which can greatly improve safety and reliability, which is a problem of batteries using organic electrolytes, and can extend the service life. It will be.
Furthermore, in an all-solid-state secondary battery, an electrode and an electrolyte can be directly arranged in series, so that a metal package that seals the battery cell, a copper wire that connects the battery cell, and a bus bar can be omitted. . Therefore, the energy density can be increased as compared with a secondary battery using an organic electrolyte, and application to an electric vehicle, a large storage battery, and the like is expected.

Japanese Patent Laid-Open No. 2001-15160

Although all-solid-state secondary batteries are highly expected as next-generation secondary batteries, research and development for their practical use has just begun, and the relationship between the configuration of positive electrodes, negative electrodes, electrolytes, etc., and battery performance There are still many unclear points.
The present invention provides an all-solid secondary battery, an all-solid-state secondary battery electrode sheet having excellent binding properties between solid electrolyte particles, reduced internal resistance (interface resistance), and excellent ion conductivity, and production thereof. It is an object to provide a method.

An all-solid-state secondary battery uses an ion conductive inorganic solid electrolyte as an electrolyte. Since this inorganic solid electrolyte is a fine particle, a certain amount of voids are generated between the electrolyte particles even if it is packed tightly. Based on the idea that the minute gaps between the electrolyte particles are a constraint for improving the ionic conductivity, the present inventors effectively closed the gaps between the electrolyte particles to reduce the internal resistance, thereby reducing the ionic conduction. We conducted intensive studies to improve the performance.
As a result, the solid electrolyte is effectively filled with the ion conductive solid consisting of the high-boiling solvent and the metal salt by coexisting a specific metal salt and a small amount of the high-boiling solvent to the solid electrolyte. It has been found that the binding property between the solid electrolytes can be increased, and as a result, the ionic conductivity can be greatly increased.
The present invention has been further studied based on these findings and has been completed.

That is, the above problem has been solved by the following means .
[1 ]
A method for producing an all-solid secondary battery having a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer in this order, wherein a composition satisfying the following (a1) to (e1) is applied on a metal foil, A method for producing an all-solid secondary battery, comprising: drying and volatilizing a solvent having a boiling point of less than 120 ° C. to form at least one of the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer. .
(A1) A metal salt belonging to Group 1 or Group 2 of the Periodic Table and containing a metal salt having ionic conductivity.
(B1) A solvent having a boiling point of 150 to 300 ° C. is contained, and the content of the solvent having a boiling point of 150 to 300 ° C. is 0.2 to 10% by mass in the solid content of the composition.
(C1) An inorganic solid electrolyte having conductivity of ions of metals belonging to Group 1 or Group 2 of the periodic table is contained.
(D1) The ratio of the content of the metal salt of (a1) to the content of the solvent of (b1) is a molar ratio of [content of metal salt] / [content of solvent] = 1.0 / 0.1-1.0 / 5.0.
(E1) A solvent having a boiling point of less than 120 ° C. is contained, and the content of the solvent having a boiling point of less than 120 ° C. is 20 to 80% by mass in the composition .
[2 ]
The manufacturing method of the electrode sheet for all-solid-state secondary batteries including apply | coating the composition which satisfy | fills following (a1)-(e1) on metal foil, and drying and volatilizing the solvent below boiling point 120 degreeC.
(A1) A metal salt belonging to Group 1 or Group 2 of the Periodic Table and containing a metal salt having ionic conductivity.
(B1) A solvent having a boiling point of 150 to 300 ° C. is contained, and the content of the solvent having a boiling point of 150 to 300 ° C. is 0.2 to 10% by mass in the solid content of the composition.
(C1) An inorganic solid electrolyte having conductivity of ions of metals belonging to Group 1 or Group 2 of the periodic table is contained.
(D1) The ratio of the content of the metal salt of (a1) to the content of the solvent of (b1) is a molar ratio of [content of metal salt] / [content of solvent] = 1.0 / 0.1-1.0 / 5.0.
(E1) A solvent having a boiling point of less than 120 ° C. is contained, and the content of the solvent having a boiling point of less than 120 ° C. is 20 to 80% by mass in the composition.
[ 3 ]
An all-solid secondary battery composition that satisfies the following (a1) to (e1).
(A1) A metal salt belonging to Group 1 or Group 2 of the Periodic Table and containing a metal salt having ionic conductivity.
(B1) A solvent having a boiling point of 150 to 300 ° C. is contained, and the content of the solvent having a boiling point of 150 to 300 ° C. is 0.2 to 10% by mass in the solid content of the composition.
(C1) An inorganic solid electrolyte having conductivity of ions of metals belonging to Group 1 or Group 2 of the periodic table is contained.
(D1) The ratio of the content of the metal salt of (a1) to the content of the solvent of (b1) is a molar ratio of [content of metal salt] / [content of solvent] = 1.0 / 0.1-1.0 / 5.0.
(E1) A solvent having a boiling point of less than 120 ° C. is contained, and the content of the solvent having a boiling point of less than 120 ° C. is 20 to 80% by mass in the composition.
[ 4 ]
The composition for an all-solid-state secondary battery according to [ 3 ], which is used to form a layer satisfying the following (a) to (d).
(A) A metal salt belonging to Group 1 or Group 2 of the Periodic Table and containing a metal salt having ionic conductivity.
(B) 0.2-10 mass% of solvent with a boiling point of 150-300 degreeC is contained.
(C) It contains an inorganic solid electrolyte having conductivity of metal ions belonging to Group 1 or Group 2 of the Periodic Table.
(D) The ratio of the content of the metal salt of (a) to the content of the solvent of (b) is a molar ratio of [content of metal salt] / [content of solvent] = 1.0 / 0.1-1.0 / 5.0.

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 the present specification, when simply described as “acryl”, it means methacryl and / or acrylic.

The all-solid-state secondary battery and the all-solid-state secondary battery electrode sheet of the present invention have reduced internal resistance due to voids between the solid electrolyte particles and show excellent ion conductivity.
Moreover, according to the manufacturing method of the all-solid-state secondary battery of this invention, the internal resistance resulting from the space | gap between solid electrolyte particles is reduced, and the all-solid-state secondary battery which shows the outstanding ion conductivity can be obtained.
In addition, according to the method for producing an electrode sheet for an all-solid-state secondary battery of the present invention, the electrode sheet for an all-solid-state secondary battery exhibiting excellent ion conductivity with reduced internal resistance due to voids between the solid electrolyte particles. Can be obtained.

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.

A preferred embodiment of the present invention will be described.
[All-solid secondary battery]
The all solid state secondary battery of the present invention has a negative electrode active material layer 2, a solid electrolyte layer 3, and a positive electrode active material layer 4 in this order.
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 according to this embodiment includes 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 stacked in this order as viewed from the negative electrode side. The adjacent layers are in direct contact with each other. 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 discharging, lithium ions (Li ⁺ ) accumulated in the negative electrode are returned to the positive electrode side, and electrons can be supplied to the working part 6. In the example of the all-solid secondary battery shown in the figure, a light bulb is adopted as the operation part 6 and it is lit by discharge.

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, the thickness of each layer is preferably 10 to 1,000 μm, and more preferably 20 μm or more and less than 500 μm.
In this specification, the positive electrode active material layer and the negative electrode active material layer may be collectively referred to as an electrode layer. The positive electrode active material layer contains a positive electrode active material, and the negative electrode active material layer contains a negative electrode active material. In order to indicate either the positive electrode active material or the negative electrode active material, or to indicate both, the active material or the electrode active material may be simply referred to. The solid electrolyte layer usually does not contain a positive electrode active material and / or a negative electrode active material.

[Negative electrode active material layer, solid electrolyte layer, positive electrode active material layer]
In the all solid state secondary battery of the present invention, at least one of the negative electrode active material layer 2, the solid electrolyte layer 3, and the positive electrode active material layer 4 satisfies the following (a) to (d). In the all solid state secondary battery and electrode sheet of the present invention, at least the solid electrolyte layer 3 preferably satisfies the following (a) to (d), and the negative electrode active material layer 2, the solid electrolyte layer 3, and the positive electrode active material layer 4 are It is also preferable that all satisfy the following (a) to (d).
(A) A metal salt belonging to Group 1 or Group 2 of the Periodic Table and containing a metal salt having ionic conductivity.
(B) 0.2-10 mass% of solvent with a boiling point of 150-300 degreeC is contained.
(C) It contains an inorganic solid electrolyte having conductivity of metal ions belonging to Group 1 or Group 2 of the Periodic Table.
(D) The ratio of the content of the metal salt of (a) to the content of the solvent of (b) is a molar ratio of [content of metal salt] / [content of solvent] = 1.0 / 0.1-1.0 / 5.0.

In the layer satisfying the above (a) to (d), the metal salt of the above (a) (hereinafter also referred to as “component (a)”), the solvent of the above (b) (hereinafter referred to as “component (b)”) And the inorganic solid electrolyte (c) (hereinafter also referred to as “component (c)”) are present uniformly in the layer (components (a) to (c) are present). It is preferable that it exists in the composition in the layer. Moreover, in the layer satisfy | filling said (a)-(d), solvent other than the said component (b) is not contained substantially (namely, in the layer satisfy | filling said (a)-(d), the said component The content of the solvent other than (b) is 0.1% by mass or less).
The components (a) to (c) will be described in order.

<Component (a)>
The component (a) is a metal salt belonging to Group 1 or Group 2 of the periodic table, and is a metal salt having ion conductivity. Here, the phrase “having ionic conductivity” for a metal salt means that the ionic conductivity is expressed when dissolved in a solvent.
More specifically, the component (a) is a metal salt capable of conducting ions that reciprocate between the positive electrode and the negative electrode by charging and discharging of the all-solid-state secondary battery of the present invention. Or it is preferable that it is a metal salt which can conduct | transmit the ion of the metal which belongs to 2nd group. When the all solid state secondary battery of the present invention is a lithium ion secondary battery, the component (a) is a metal salt capable of conducting lithium ions. Here, “capable of conducting metal ions” is synonymous with having metal ion conductivity.
The component (a) is preferably a metal salt (lithium salt) selected from the following (a-1) and (a-2).

(A-1) LiA _x D _y
In (a-1), A is P, B, As, Sb, Cl, Br or I, or two or more elements selected from P, B, As, Sb, Cl, Br and I The combination of is shown. D represents F or O. x is 1-6, and 1-3 are more preferable. y is 1-12, and 4-6 are more preferable.
The Preferred examples of (a-1), for _{example, LiPF 6, LiBF 4, LiAsF} 6, and an inorganic fluoride salt selected from LiSbF _6, as well _as perhalogenated selected from LiClO 4, Libro _4, and LiIO ₄ There may be mentioned acid salts.

(A-2) LiN (R ^f SO ₂ ) ₂
In (a-2), R ^f represents a fluorine atom or a perfluoroalkyl group. 1-4 are preferable and, as for carbon number of this perfluoroalkyl group, 1-2 are more preferable.
As preferable specific examples of the above (a-2), for example, LiN (CF ₃ SO ₂ ) ₂ , LiN (CF ₃ CF ₂ SO ₂ ) ₂ , LiN (FSO ₂ ) ₂ , and LiN (CF ₃ SO ₂ ) ( And a perfluoroalkanesulfonylimide salt selected from C ₄ F ₉ SO ₂ ).

Among these, from the viewpoint of ion conductivity after dissolution of the solvent, the component (a) includes LiPF ₆ , LiBF ₄ , LiClO ₄ , LiBrO ₄ , LiN (CF ₃ SO ₂ ) ₂ , LiN (FSO ₂ ) ₂ , and LiN. A metal salt selected from (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ) is preferred, selected from LiPF ₆ , LiBF ₄ , LiClO ₄ , LiN (CF ₃ SO ₂ ) ₂ , and LiN (FSO ₂ ) _2. Metal salts are more preferable, and metal salts selected from LiClO ₄ , LiN (CF ₃ SO ₂ ) ₂ , and LiN (FSO ₂ ) ₂ are more preferable.
In the present invention, one or more metal salts can be used as the component (a).
In the layer satisfying the above (a) to (d), the content of the component (a) is preferably 2 to 60% by mass, more preferably 4 to 40% by mass, and further preferably 6 to 20% by mass.

In the all solid state secondary battery of the present invention, when there is a layer that does not contain the component (b) among the negative electrode active material layer 2, the solid electrolyte layer 3, and the positive electrode active material layer 4, this component (b) is not contained. The layer may contain the component (a). Moreover, when there exists a layer which does not contain a component (c) among the negative electrode active material layers 2 and the positive electrode active material layers 4, the said component (a) is contained in the layer which does not contain this component (c). Also good.
When the component (a) is contained in a layer not containing the component (b) or in a layer not containing the component (c), in a layer not containing the component (b) or containing the component (c) In the layer not to be used, the content of the component (a) is preferably 1% by mass or less, and more preferably 0.5% by mass or less.

<Component (b)>
Component (b) is a solvent having a boiling point of 150 to 300 ° C. When the boiling point of the component (b) is 150 to 300 ° C., it is difficult to volatilize even if it is contained in the layer, and by mixing it with the component (a), both are mixed and an ion conductive solid is formed. Is done. That is, the component (b) does not exist as a liquid solvent having fluidity in the layer. In the present invention, the solid material containing the component (a) and the component (b) is a solid material at least at 50 ° C. or lower. The reason why this solid matter increases the ionic conductivity is not clear, but it is because the solid matter enters the gaps between the solid electrolyte particles and closes the gaps, effectively increasing the adhesion between the solid electrolyte particles. Conceivable.
In the present invention, the boiling point means a boiling point (standard boiling point) at 1 atm.

The component (b) is contained in the layer satisfying the above (a) to (d) in the all-solid-state secondary battery of the present invention in an amount of 0.2 to 10% by mass, preferably 1 to 9% by mass, More preferably 2 to 7% by mass is contained. Thus, in the present invention, the amount of the component (b) in the layer needs to be a very small amount. When the amount of the component (b) in the layer is 0.2 to 10% by mass, the direct contact between the solid electrolytes is not hindered, and the void formed between the solid electrolytes is made of a conductive solid. It is thought that it can be effectively blocked.
In the present invention, even if a solvent (liquid) is contained in each layer of the battery or electrode sheet, it is referred to as an all-solid secondary battery if the total content of the solvent is 10% by mass or less in the layer.
In the layer satisfying the above (a) to (d), a solvent other than the component (b) is practically not contained. That is, in the layer satisfying the above (a) to (d), the content of the solvent other than the component (b) is 2% by mass or less, preferably 1% by mass or less, and more preferably 0.1% by mass or less.

From the viewpoint of solubility of the component (a), the component (b) has * -CN, * -O- *, * -O-C (= O)-*, * -C (= O in its chemical structure. ) -NR ^S1- * (R ^S1 represents a hydrogen atom or a substituent), * -O-C (= O) -O- *, = NR ^S2 (R ^S2 represents a hydrogen atom or a substituent), * It preferably has a group selected from N— *, * —NH—C (═O) —O— *, and * —OH, * —O—C (═O) —O— *, * —CN. , * —O—C (═O) — * and * —O— * are more preferable.
R ^S1 and R ^S2 represent a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom or a substituent. Preferred examples of this substituent include an alkyl group (preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, and still more preferably an alkyl group having 1 to 3 carbon atoms), an aryl group (preferably having 6 to 6 carbon atoms) 20, more preferably an aryl group having 6 to 15 carbon atoms, still more preferably an aryl group having 6 to 10 carbon atoms), and an alkenyl group (preferably an alkenyl group having 2 to 18 carbon atoms, more preferably an alkenyl group having 2 to 12 carbon atoms). be able to. The alkyl group is preferably an alkyl group having a fluorine atom. R ^S1 and R ^S2 are more preferably a hydrogen atom, an alkyl group, an aryl group, or a fluorine atom.
The above * indicates a linking site in a state incorporated in the chemical structure of the solvent.

As for a component (b), it is more preferable that the boiling point is 180-300 degreeC, and 200-280 degreeC is further more preferable. Preferable specific examples of the solvent that can be used as the component (b) include, for example, ethylene carbonate (261 ° C.), propylene carbonate (240 ° C.), fluoroethylene carbonate (210 ° C.), benzonitrile (190 ° C.), γ-butyrolactone ( 204 ° C), γ-valerolactone (207 ° C), glutaronitrile (285 ° C), adiponitrile (295 ° C), 3-methoxypropionitrile (164 ° C), sulfolane (285 ° C), trimethyl phosphate (197 ° C) Dimethyl sulfoxide (189 ° C.), ethylene glycol (198 ° C.), diethylene glycol (245 ° C.), ethylene glycol monoethyl ether acetate (156 ° C.), tetraethylene glycol dimethyl ether (275 ° C.), dimethylformamide (153 ° C.). I can make it. These may be used alone or in combination of two or more.
Among these, from the viewpoints of solubility and ion conductivity of component (a), ethylene carbonate (261 ° C.), propylene carbonate (240 ° C.), fluoroethylene carbonate (210 ° C.), benzonitrile (190 ° C.), γ-butyrolactone ( 204 ° C), γ-valerolactone (207 ° C), glutaronitrile (285 ° C), adiponitrile (295 ° C), ethylene glycol monoethyl ether acetate (156 ° C), and tetraethylene glycol dimethyl ether (275 ° C). It is preferable to use one or more solvents.
The temperature in the parenthesis indicates the boiling point.

  In the layer satisfying the above (a) to (d), the ratio of the content of the component (a) to the content of the component (b) is a molar ratio [content of component (a)] / [component ( b) Content] = 1.0 / 0.1 to 1.0 / 5.0, and 1.0 / 0.2 to 1.0 / 3.0 from the viewpoint of ion conductivity and safety. Is preferable, 1.0 / 0.4 to 1.0 / 2.0 is more preferable, 1.0 / 0.4 to 1.0 / 1.8 is more preferable, and 1.0 / 0.5 to 1 0.0 / 1.5 is more preferable.

<Component (c)>
Component (c) is an inorganic solid electrolyte having conductivity of metal ions belonging to Group 1 or Group 2 of the Periodic Table (ie, capable of conducting ions of metals belonging to Group 1 or Group 2 of the Periodic Table) Inorganic solid electrolyte). More specifically, it is an inorganic solid electrolyte capable of conducting metal ions reciprocating between a positive electrode and a negative electrode by charging and discharging of the all solid state secondary battery of the present invention. The metal ions that can be conducted by the inorganic solid electrolyte are preferably lithium ions or sodium ions. The inorganic solid electrolyte will be described in detail.

In the present invention, the inorganic solid electrolyte is an inorganic solid electrolyte, and the solid electrolyte is a solid electrolyte capable of moving at least the specific metal ion therein. Since it does not contain organic substances as the main ion conductive material, it is clearly distinguished from organic solid electrolytes (polymer electrolytes typified by PEO and the like, organic electrolyte salts typified by LiTFSI and the like). In addition, since the inorganic solid electrolyte is solid in a steady state, it is not usually dissociated or released into cations and anions. In this respect, it is also clearly distinguished from the electrolyte solution and inorganic electrolyte salts (LiPF ₆ , LiBF ₄ , LiFSI, LiCl, etc.) in which cations and anions are dissociated or liberated. Inorganic solid electrolytes usually do not have electronic conductivity.

  As the inorganic solid electrolyte that can be employed in the present invention, a solid electrolyte material applied to this type of product can be appropriately selected and used. Typical examples of inorganic solid electrolytes include (i) sulfide-based inorganic solid electrolytes and (ii) oxide-based inorganic solid electrolytes.

(I) Sulfide-based inorganic solid electrolyte The sulfide-based inorganic solid electrolyte contains sulfur (S) and has ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and What has electronic insulation is preferable. The sulfide-based inorganic solid electrolyte preferably contains at least Li, S and P as elements and has lithium ion conductivity. However, depending on the purpose or the case, other than Li, S and P may be used. An element may be included.
For example, a lithium ion conductive inorganic solid electrolyte that satisfies the composition represented by the following formula (1) can be given.

L _a1 M _b1 P _c1 S _d1 A _e1 (1)

In the formula (1), L represents an element selected from Li, Na and K, and Li is preferable.
M represents an element selected from B, Zn, Sn, Si, Cu, Ga, Sb, Al, and Ge. Among these, M is preferably B, Sn, Si, Al, or Ge, and more preferably Sn, Al, or Ge. A represents I, Br, Cl or F, preferably I or Br, and particularly preferably I. a1 to e1 indicate the composition ratio of each element, and a1: b1: c1: d1: e1 satisfies 1 to 12: 0 to 1: 1: 2 to 12: 0 to 5. a1 is preferably 1 to 9, and more preferably 1.5 to 4. b1 is preferably 0 to 0.5. d1 is preferably from 3 to 7, and more preferably from 3.25 to 4.5. e1 is preferably 0 to 3, and more preferably 0 to 1.

  In the formula (1), the composition ratio of L, M, P, S and A is preferably such that b1 and e1 are 0, more preferably b1 = 0 and e1 = 0 and the ratio of a1, c1 and d1 is a1: c1: d1 = 1-9: 1: 3-7, more preferably b1 = 0, e1 = 0 and a1: c1: d1 = 1.5-4: 1: 3.25-4. 5. As will be described later, the composition ratio of each element can be controlled by adjusting the blending amount of the raw material compound in producing the sulfide-based solid electrolyte.

The sulfide-based inorganic solid electrolyte may be amorphous (glass) or crystallized (glass ceramic), or only part of it 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 sulfide-based inorganic solid electrolyte includes [1] at least one of lithium sulfide (Li ₂ S) and phosphorus sulfide (for example, diphosphorus pentasulfide (P ₂ S ₅ )), [2] lithium sulfide, simple phosphorus, and simple sulfur. Or [3] It can be produced by the reaction of lithium sulfide, phosphorus sulfide (for example, diphosphorus pentasulfide (P ₂ S ₅ )) and at least one of elemental phosphorus and elemental sulfur.

The ratio of Li ₂ S to P ₂ S ₅ in the Li—PS glass and the Li—PS glass glass ceramic 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 77:23. By setting the ratio of Li ₂ S to P ₂ S ₅ within this range, the lithium ion conductivity can be further 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 upper limit, it is practical that it is 1 × 10 ⁻¹ S / cm 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 _{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, such as _{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—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-LiI-Li 2 O-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 , a crystalline and / or amorphous raw material composition comprising Li ₂ S—GeS ₂ —P ₂ S ₅ , Li ₁₀ GeP ₂ S ₁₂ is preferred because it has high lithium ion conductivity. 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 inorganic solid electrolyte contains oxygen (O) and has ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and What has electronic insulation is preferable.

As a specific compound example, for example, Li _xa La _ya TiO ₃ [xa satisfies 0.3 ≦ xa ≦ 0.7, and ya satisfies 0.3 ≦ ya ≦ 0.7. (LLT); Li _xb La _yb Zr _zb M ^bb _{mb Onb} (M ^bb is Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In or Sn, or Al, Mg , Ca, Sr, V, Nb, Ta, Ti, Ge, In and Sn are combinations of two or more elements, xb satisfies 5 ≦ xb ≦ 10, and yb satisfies 1 ≦ yb ≦ 4 , Zb satisfies 1 ≦ zb ≦ 4, mb satisfies 0 ≦ mb ≦ 2, and nb satisfies 5 ≦ nb ≦ 20; Li _xc B _yc M ^cc _zc O _nc (M ^cc is C, S, Al, Si, Ga, Ge, In, or Sn, or a combination of two or more elements selected from C, S, Al, Si, Ga, Ge, In, and Sn, where xc is 0 ≦ xc ≦ 5, yc satisfies 0 ≦ yc ≦ 1 And, zc satisfies 0 ≦ zc ≦ 1, nc satisfies _{0 ≦ nc ≦ 6);.} Li xd (Al, Ga) yd (Ti, Ge) zd Si ad P md O nd (xd is 1 ≦ xd ≦ 3, yd satisfies 0 ≦ yd ≦ 1, zd satisfies 0 ≦ zd ≦ 2, ad satisfies 0 ≦ ad ≦ 1, md satisfies 1 ≦ md ≦ 7, nd satisfies 3 ≦ nd ≦ 13 ^{_{meet);. Li (3-2xe) M}} ee xe D ee O (xe represents a number of 0 to ^{0.1, .D ee M ee} is representative of a divalent metal atom is a halogen atom or Li _xf Si _yf O _zf (xf satisfies 1 ≦ xf ≦ 5, yf satisfies 0 <yf ≦ 3, and zf satisfies 1 ≦ zf ≦ 10). _{); Li xg S yg O zg} (xg satisfies 1 ≦ xg ≦ 3 yg satisfies 0 <yg ≦ 2, zg satisfies _{1 ≦ zg ≦ 10);.} Li 3 BO 3 -Li 2 SO 4; Li 2 O-B 2 O 3 -P 2 O 5; Li 2 O- _{SiO 2; Li 6 BaLa 2 Ta} 2 O 12; Li 3 PO (4-3 / 2w) N w (w is _{w <1); LISICON Li 3.5} Zn 0 with (Lithium super ionic conductor) type crystal structure _{.25 GeO 4; La 0.55 Li 0.35} TiO 3 having a perovskite crystal structure; NASICON (Natrium super ionic conductor) crystal structure having _{LiTi 2 P 3 O 12; Li} 1 + xh + yh (Al, Ga) xh ( _{Ti, Ge) 2-xh Si} yh P 3-yh O 12 (xh is 0 ≦ xh Met 1, yh satisfies 0 ≦ yh ≦ 1. And Li ₇ La ₃ Zr ₂ O ₁₂ (LLZ) having a garnet-type crystal structure. Phosphorus compounds containing Li, P and O are also desirable. For example, lithium phosphate (Li ₃ PO ₄ ); LiPON obtained by substituting a part of oxygen of lithium phosphate with nitrogen; LiPOD ¹ (D ¹ is preferably Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Ag, Ta, W, Pt or Au, or Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Ag , Ta, W, Pt, and Au, or a combination of two or more elements.). Further, LiA ¹ ON (A ¹ is preferably Si, B, Ge, Al, C or Ga, or two or more elements selected from Si, B, Ge, Al, C and Ga. Etc.) can also be preferably used.

  The volume average particle diameter 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. In addition, the measurement of the average particle diameter of an inorganic solid electrolyte particle is performed in the following procedures. The inorganic solid electrolyte particles are diluted and adjusted in a 20 ml sample bottle using water (heptane in the case of a substance unstable to water). The diluted dispersion sample is irradiated with 1 kHz ultrasonic waves for 10 minutes and used immediately after that. Using this dispersion liquid sample, using a laser diffraction / scattering particle size distribution measuring apparatus LA-920 (manufactured by HORIBA), data acquisition was performed 50 times using a quartz cell for measurement at a temperature of 25 ° C. Get the diameter. For other detailed conditions and the like, refer to the description of JISZ8828: 2013 “Particle Size Analysis—Dynamic Light Scattering Method” as necessary. Five samples are prepared for each level, and the average value is adopted.

In the all-solid-state secondary battery of the present invention, the content of the component (c) in the layer satisfying the above (a) to (d) is the function of this layer (whether it is a solid electrolyte layer or an electrode layer). ) Is adjusted appropriately. When the layer satisfying the above (a) to (d) is a solid electrolyte layer, the content of the component (c) in the solid electrolyte layer is preferably 5 to 98% by mass, more preferably 10 to 97% by mass. 20-95 mass% is further more preferable, 30-92 mass% is further more preferable, and 40-90 mass% is further more preferable.
Moreover, when the layer satisfy | filling said (a)-(d) is an electrode layer, 2-90 mass% is preferable, and, as for content of the said component (c) in this electrode layer, 5-90 mass% is more preferable. 10 to 90 mass% is more preferable, 20 to 80 mass% is further preferable, 20 to 70 mass% is further preferable, 20 to 50 mass% is further preferable, and 25 to 40 mass% is further preferable.
The said inorganic solid electrolyte may be used individually by 1 type, or may be used in combination of 2 or more type.

In the all solid state secondary battery of the present invention, when there is a layer that does not contain the component (a) among the negative electrode active material layer 2, the solid electrolyte layer 3, and the positive electrode active material layer 4, this component (a) is not contained. The layer preferably contains the component (c). Moreover, when there exists a layer which does not contain the said component (b) among the negative electrode active material layer 2, the solid electrolyte layer 3, and the positive electrode active material layer 4, the said component (c) is also contained in the layer which does not contain this component (b). ) Is preferably included. That is, the component (c) is preferably included in all layers of the negative electrode active material layer 2, the solid electrolyte layer 3, and the positive electrode active material layer 4.
When the component (c) is contained in a layer not containing the component (a) or the component (b), the component (c) in the layer not containing the component (a) or the component (b) The content is appropriately adjusted depending on the function of the layer (whether it is a solid electrolyte layer or an electrode layer). When the layer not containing the component (a) or the component (b) is a solid electrolyte layer, the content of the component (c) in the solid electrolyte layer is preferably 10 to 99.5% by mass. More preferably, it is 20-99 mass%, More preferably, it is 30-98 mass%, More preferably, it is 40-98 mass%, More preferably, it is 50-95 mass%, More preferably, it is 60-93 mass%, More preferably, it is 70 It is -90 mass%, More preferably, it is 80-90 mass%.
Moreover, when the layer which does not contain the said component (a) or the said component (b) is an electrode layer, 2-90 mass% is preferable, and, as for content of the said component (c) in this electrode layer, 5-90 mass. % Is more preferable, 10 to 90% by mass is further preferable, 20 to 80% by mass is further preferable, 20 to 70% by mass is further preferable, and 25 to 40% by mass is further preferable.

  In the layer satisfying the above (a) to (d), the all solid secondary battery of the present invention includes the content of the component (a) (metal salt), the content of the component (b) (solvent), and the component ( c) Content ratio of (inorganic solid electrolyte) is mass ratio, [content of component (a)] / [content of component (b)] / [content of component (c)] = 3 It is preferable that it is 50 / 0.5-10 / 50-98, and it is more preferable that it is 6-15 / 1.5-5 / 80-90. By setting it within the preferable range, ion conductivity can be further increased.

<Binder>
In the all solid state secondary battery of the present invention, each layer (that is, a negative electrode active material layer, a solid electrolyte layer and / or a positive electrode active material layer, the same shall apply hereinafter) preferably contains a binder. The binder that can be 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. For example, a binder made of a resin described below is preferable.

Examples of the fluorine-containing resin include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and a copolymer of polyvinylidene fluoride and hexafluoropropylene (PVdF-HFP). Examples of the plastic resin include polyethylene, polypropylene, styrene butadiene rubber (SBR), hydrogenated styrene butadiene rubber (HSBR), butylene rubber, acrylonitrile butadiene rubber, polybutadiene, polyisoprene, and polyisoprene latex.
Examples of the acrylic resin include poly (meth) methyl acrylate, poly (meth) ethyl acrylate, poly (meth) acrylate isopropyl, poly (meth) acrylate isobutyl, poly (meth) butyl acrylate, poly (meth) ) Hexyl acrylate, poly (meth) acrylate octyl, poly (meth) acrylate dodecyl, poly (meth) acrylate stearyl, poly (meth) acrylate 2-hydroxyethyl, poly (meth) acrylic acid, poly (meth) ) Benzyl acrylate, poly (meth) acrylate glycidyl, poly (meth) acrylate dimethylaminopropyl, and copolymers of monomers constituting these resins.
Examples of the urethane resin include polyurethane.
Further, copolymers with other vinyl monomers are also preferably used. Examples include poly (meth) acrylate methyl-polystyrene copolymer, poly (meth) acrylate methyl-acrylonitrile copolymer, poly (meth) acrylate butyl-acrylonitrile-styrene copolymer, and the like.
These may be used individually by 1 type, or may be used in combination of 2 or more type.

  The binder that can be used in the present invention is preferably polymer particles, and the average particle diameter φ 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. preferable. It is preferable from the viewpoint of improving the output density that the average particle diameter φ is in the above preferred range.

The average particle diameter φ of the polymer particles that can be used in the present invention is based on the measurement conditions and definitions described below unless otherwise specified.
The polymer particles are diluted and prepared in a 20 ml sample bottle using an arbitrary solvent (an organic solvent used for preparing the solid electrolyte composition, for example, 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. The obtained volume average particle diameter is defined as the average particle diameter φ. 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 secondary battery, for example, after disassembling the battery and peeling off the electrode, the electrode material is measured according to the measurement method of the average particle diameter φ of the polymer particles, This can be done by excluding the measured value of the average particle diameter of the particles other than the polymer particles that has been measured in advance.

  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 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 by using a differential scanning calorimeter “X-DSC7000” (manufactured by SII Nanotechnology Co., Ltd.) using a dry sample. 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 lowering start point and the lowering end point of the DSC chart.

The polymer constituting the binder that can be 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.

  In the all solid state secondary battery of the present invention, when there is a layer containing a binder, the content of the binder in the layer is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and 1% by mass or more. Is more preferable. The upper limit is preferably 10% by mass or less, more preferably 5% by mass or less, further preferably 3.5% by mass or less, and further preferably 2% by mass or less from the viewpoint of battery characteristics.

<Dispersant>
In the all solid state secondary battery of the present invention, each layer preferably 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. Play.

The dispersant is composed of molecules having a molecular weight of 200 or more and less than 3000, and a functional group selected from the following functional group (I) and an alkyl group having 8 or more carbon atoms or an aryl group having 10 or more carbon atoms in the same molecule. contains.
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 Base

  The molecular weight of the dispersant is preferably 300 or more and less than 2,000, more preferably 500 or more and less than 1,000. When the amount is not more than the above upper limit value, the aggregation of particles is less likely to occur, and the decrease in output can be effectively suppressed. Moreover, it becomes difficult to volatilize in the step which apply | coats and dries a solid electrolyte composition slurry as it is more than the said lower limit.

  In the all solid state secondary battery of the present invention, when there is a layer containing a dispersant, the content of the dispersant in the layer is preferably 0.01 to 10% by mass, preferably 0.1 to 5% by mass. -3 mass% is more preferable.

<Conductive aid>
In the all solid state secondary battery of the present invention, each layer preferably contains a conductive additive. What is known as a general conductive support agent can be used as the conductive support agent. For example, graphites such as natural graphite and artificial graphite, carbon blacks such as acetylene black, ketjen black and furnace black, amorphous carbon such as needle coke, vapor-grown carbon fiber and carbon nanotubes, which are electron conductive materials Carbon fibers such as graphene, carbonaceous materials such as graphene and fullerene, metal powders such as copper and nickel, and metal fibers may be used, and conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene, and polyphenylene derivatives may be used. It may be used. Moreover, 1 type may be used among these and 2 or more types may be used.

<Positive electrode active material>
Next, the positive electrode active material used for the positive electrode active material layer 4 of the all-solid-state secondary battery of the present invention will be described. The positive electrode active material is preferably one that can reversibly insert and release lithium ions. The material is not particularly limited, and may be a transition metal oxide or an element that can be combined with Li such as sulfur. Among them, it is preferable to use a transition metal oxide, and it is more preferable to have one or more elements selected from Co, Ni, Fe, Mn, Cu and V as a transition metal element.
Specific examples of the transition metal oxide include (MA) a transition metal oxide having a layered rock salt structure, (MB) a transition metal oxide having a spinel structure, (MC) a lithium-containing transition metal phosphate compound, (MD And lithium-containing transition metal halide phosphate compounds, (ME) lithium-containing transition metal silicate compounds, and the like.

(MA) As specific examples of the transition metal oxide having a layered rock salt structure, LiCoO ₂ (lithium cobaltate [LCO]), LiNi ₂ O ₂ (lithium nickelate) LiNi _0.85 Co _0.10 Al _0.05 O ₂ (nickel cobalt lithium aluminum oxide [NCA]), LiNi _0.33 Co _0.33 Mn _0.33 O ₂ (nickel manganese lithium cobalt oxide [NMC]), LiNi _0.5 Mn _0.5 O ₂ (manganese) Lithium nickelate).
Specific examples of the transition metal oxide having an (MB) spinel structure include LiCoMnO _4, Li ₂ FeMn ₃ O ₈ , Li ₂ CuMn ₃ O ₈ , Li ₂ CrMn ₃ O _{8, and} Li ₂ NiMn ₃ O _8. .
Examples of (MC) lithium-containing transition metal phosphate compounds include olivine-type iron phosphate salts such as LiFePO ₄ and Li ₃ Fe ₂ (PO ₄ ) ₃ , iron pyrophosphates such as LiFeP ₂ O ₇ , LiCoPO _{4 and the} like. And monoclinic Nasicon type vanadium phosphate salts such as Li ₃ V ₂ (PO ₄ ) ₃ (vanadium lithium phosphate).
The (MD) lithium-containing transition metal halogenated phosphate compound, for _example, Li 2 FePO ₄ F such fluorinated phosphorus iron _salt, Li 2 MnPO ₄ hexafluorophosphate manganese salts such as _F, Li 2 CoPO ₄ F Cobalt fluorophosphates such as
Examples of the (ME) lithium-containing transition metal silicate compound include Li ₂ FeSiO ₄ , Li ₂ MnSiO ₄ , Li ₂ CoSiO _{4, and the} like.

  The volume average particle diameter (sphere conversion 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. For example, the thickness can be 0.1 μm to 50 μm. In order to make the positive electrode active material have a predetermined particle size, an ordinary 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 volume average particle diameter (sphere conversion average particle diameter) of the positive electrode active material particles can be measured using a laser diffraction / scattering particle size distribution analyzer LA-920 (trade name, manufactured by HORIBA).

  Content of the positive electrode active material in the positive electrode active material layer 4 is not specifically limited, 10-90 mass% is preferable in a positive electrode active material layer, 20-80 mass% is more preferable, 30-80 mass is more preferable, 50-75 mass% is especially preferable.

  The positive electrode active materials may be used alone or in combination of two or more.

<Negative electrode active material>
Next, the negative electrode active material used for the negative electrode active material layer of the all solid state secondary battery of the present invention will be described. The negative electrode active material is preferably one that can reversibly insert and release lithium ions. The material is not particularly limited, and is a carbonaceous material, a metal oxide such as tin oxide or silicon oxide, a metal composite oxide, a lithium alloy such as lithium alone or a lithium aluminum alloy, and a lithium such as Sn, Si, or In. And metals capable of forming an alloy. Of these, carbonaceous materials or lithium composite oxides are preferably used from the viewpoint of reliability. In addition, the metal composite oxide is preferably capable of inserting and extracting lithium. The material is not particularly limited, but 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. For example, carbon black such as petroleum pitch, acetylene black (AB), artificial graphite such as natural graphite and vapor-grown graphite, and various synthetic resins such as PAN (polyacrylonitrile) resin and furfuryl alcohol resin are fired. A carbonaceous material can be mentioned. Further, various carbon fibers such as PAN-based carbon fiber, cellulose-based carbon fiber, pitch-based carbon fiber, vapor-grown carbon fiber, dehydrated PVA (polyvinyl alcohol) -based carbon fiber, lignin carbon fiber, glassy carbon fiber, activated carbon fiber, etc. And mesophase microspheres, graphite whiskers, flat graphite and the like.

  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, or the like is used. You can also.

  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 °. It is preferable that it is 5 times or less, and it is particularly preferable not to have 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, Particularly 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 , SnSiS ₃ is preferred. 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 diameter, 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 can be measured by the same method as the above-described method for measuring the volume average particle diameter of the positive electrode active material.

It is also preferable that the negative electrode active material contains a titanium atom. More specifically, since Li ₄ Ti ₅ O ₁₂ has a small volume fluctuation at the time of occlusion and release of lithium ions, it has excellent rapid charge / discharge characteristics, suppresses electrode deterioration, and improves the life of lithium ion secondary batteries. This is preferable.

  Content of the negative electrode active material in the negative electrode active material layer 2 is not specifically limited, It is preferable that it is 10-80 mass% in a negative electrode active material layer, 20-80 mass% is more preferable, 30-80 mass% It is more preferable that it is 40 to 75% by mass.

  The said negative electrode active material may be used individually by 1 type, or may be used in combination of 2 or more type.

[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.

[Production of all-solid-state secondary batteries]
The manufacturing method of the all-solid-state secondary battery of this invention apply | coats the composition (slurry) which satisfy | fills the following (a1)-(e1) on the metal foil which functions as a collector, and it is dried and has a boiling point of less than 120 degreeC. Volatilizing the solvent (solvent (e1) below). This drying is performed under the condition that all of the solvent having a boiling point of less than 120 ° C. is volatilized and the solvent having a boiling point of 150 to 300 ° C. is practically not volatilized. Specific drying conditions will be described later.

(A1) A metal salt belonging to Group 1 or Group 2 of the Periodic Table and containing a metal salt having ionic conductivity.
(B1) A solvent having a boiling point of 150 to 300 ° C. is contained, and the content of the solvent having a boiling point of 150 to 300 ° C. is 0.2 to 10% by mass in the solid content of the composition.
(C1) Metal ions belonging to Group 1 or Group 2 of the periodic table contain a conductive inorganic solid electrolyte.
(D1) The ratio of the content of the metal salt of (a1) to the content of the solvent of (b1) is a molar ratio of [content of metal salt] / [content of solvent] = 1.0 / 0.1-1.0 / 5.0.
(E1) A solvent having a boiling point of less than 120 ° C. is contained, and the content of the solvent having a boiling point of less than 120 ° C. is 20 to 80% by mass in the composition.

Each of the layers constituting the all-solid-state secondary battery formed by volatilizing the component (e1) by applying a composition satisfying the above (a1) to (e1) and drying it is the above-described (a) to (d). ). That is, the component (a) described above is derived from the metal salt defined in (a1) above, the component (b) described above is derived from the solvent defined in (b1) above, and the component (c) described above is derived from the above. It is derived from the inorganic solid electrolyte defined in (c1). Therefore, the content of the components (a) to (c) in each layer described above and the solid content of the composition (in the present invention, the solvent (b1) is included in the solid content. In the present invention, the term “solid content” means the content of the above components (a1) to (c1) of all components contained in the composition excluding the solvent having a boiling point of less than 150 ° C.) It becomes.
The composition satisfying the above (a1) to (e1) is a solvent other than the solvent of (b1) and contains substantially no solvent other than the solvent of (e1) (that is, the above (a1) ) To (e1), the content of the solvent other than the component (b1) and the solvent other than the solvent (e1) is 0.1% by mass or less.

  In the method for producing an all-solid-state secondary battery of the present invention, “a composition satisfying (a1) to (e1) is applied on a metal foil and dried to obtain a solvent having a boiling point of less than 120 ° C. (solvent of (e1)). “Volatilize” means to include the following embodiments (i) to (vi).

(I) A composition satisfying the above (a1) to (e1) and containing a negative electrode active material is directly applied on a metal foil, dried to volatilize a solvent having a boiling point of less than 120 ° C., and a negative electrode on the metal foil. An embodiment in which an active material layer is formed.
(Ii) A composition satisfying the above (a1) to (e1) and containing a positive electrode active material is directly applied on a metal foil, dried to volatilize a solvent having a boiling point of less than 120 ° C., and a positive electrode on the metal foil. An embodiment in which an active material layer is formed.
(Iii) A composition satisfying the above (a1) to (e1) is directly applied on the negative electrode active material layer of the laminate having a two-layer structure comprising the metal foil and the negative electrode active material layer, and dried to have a boiling point of 120 ° C. A mode in which less than the solvent is volatilized to form a solid electrolyte layer on the negative electrode active material layer.
(Iv) A composition satisfying the above (a1) to (e1) is directly applied on a positive electrode active material layer of a laminate having a two-layer structure comprising a metal foil and a positive electrode active material layer, and dried to have a boiling point of 120 ° C. A mode in which less than the solvent is volatilized to form a solid electrolyte layer on the positive electrode active material layer.
(V) A composition satisfying the above (a1) to (e1) and containing a positive electrode active material directly on a solid electrolyte layer of a laminate having a three-layer structure comprising a metal foil, a negative electrode active material layer, and a solid electrolyte layer A mode in which a positive electrode active material layer is formed on the solid electrolyte layer by coating and drying to volatilize a solvent having a boiling point of less than 120 ° C.
(Vi) A composition satisfying the above (a1) to (e1) and containing a negative electrode active material directly on a solid electrolyte layer of a laminate having a three-layer structure comprising a metal foil, a positive electrode active material layer, and a solid electrolyte layer A mode in which a negative electrode active material layer is formed on the solid electrolyte layer by coating and drying to volatilize a solvent having a boiling point of less than 120 ° C.

  In order to produce the all-solid-state secondary battery of the present invention according to the aspect (i) above, a solid electrolyte layer and a positive electrode active material layer are formed in this order on the negative electrode active material layer formed in the above (i) in this order. Thus, a laminate having a four-layer structure is obtained, and a current collector (metal foil) is stacked on the positive electrode active material layer to prepare a laminate having a five-layer structure. In this case, the solid electrolyte layer and the positive electrode active material layer may or may not satisfy the above (a) to (d). The obtained five-layered laminate may be used as an all-solid secondary battery as it is. Normally, this five-layered laminate is housed in an appropriate housing (such as a coin case) as an all-solid secondary battery. Use.

  In order to produce the all-solid-state secondary battery of the present invention according to the aspect (ii) above, the solid electrolyte layer and the negative electrode active material layer are formed in this order on the positive electrode active material layer formed in the above (ii) in the usual manner. Thus, a laminate having a four-layer structure is obtained, and a current collector (metal foil) is stacked on the negative electrode active material layer to prepare a laminate having a five-layer structure. In this case, the solid electrolyte layer and the negative electrode active material layer may or may not satisfy the above (a) to (d). The obtained electrode sheet having a five-layer structure may be used as an all-solid secondary battery as it is. Usually, the laminate having the five-layer structure is housed in an appropriate housing (such as a coin case) as an all-solid secondary battery. Use.

  In order to produce the all-solid-state secondary battery of the present invention according to the aspect (iii) above, a positive electrode active material layer is formed by a conventional method on the solid electrolyte layer formed in (iii) above, and a four-layer structure is laminated. And a current collector (metal foil) is stacked on the positive electrode active material layer to prepare a laminate having a five-layer structure. In this case, the negative electrode active material layer and the positive electrode active material layer may or may not satisfy the above (a) to (d). The obtained five-layered laminate may be used as an all-solid secondary battery as it is. Normally, this five-layered laminate is housed in an appropriate housing (such as a coin case) as an all-solid secondary battery. Use.

  In order to produce the all-solid-state secondary battery of the present invention according to the aspect (iv) above, a negative electrode active material layer is formed by a conventional method on the solid electrolyte layer formed in (iv) above, and a four-layer structure is laminated. A current collector is obtained, and a current collector (metal foil) is stacked on the negative electrode active material layer to prepare a laminate having a five-layer structure. In this case, the positive electrode active material layer and the negative electrode active material layer may or may not satisfy the above (a) to (d). The obtained five-layered laminate may be used as an all-solid secondary battery as it is. Normally, this five-layered laminate is housed in an appropriate housing (such as a coin case) as an all-solid secondary battery. Use.

  In order to produce the all-solid-state secondary battery of the present invention according to the aspect (v), a laminate having a five-layer structure in which a current collector (metal foil) is stacked on the positive electrode active material layer formed in (v) above. To prepare. In the aspect (v), the negative electrode active material layer and the solid electrolyte layer may or may not satisfy the above (a) to (d). The obtained five-layered laminate may be used as an all-solid secondary battery as it is. Normally, this five-layered laminate is housed in an appropriate housing (such as a coin case) as an all-solid secondary battery. Use.

  In order to produce the all-solid-state secondary battery of the present invention according to the above aspect (vi), a current collector (metal foil) is laminated on the negative electrode active material layer formed in the above (vi) to form a laminate having a five-layer structure. To prepare. In the aspect (vi), the positive electrode active material layer and the solid electrolyte layer may or may not satisfy the above (a) to (d). The obtained five-layered laminate may be used as an all-solid secondary battery as it is. Normally, this five-layered laminate is housed in an appropriate housing (such as a coin case) as an all-solid secondary battery. Use.

  The solvent in the above (e1) is not particularly limited as long as the boiling point is lower than 120 ° C. Specific examples include the following.

Alcohol compounds:
Examples include methyl alcohol, ethyl alcohol, 1-propyl alcohol, 2-propyl alcohol, and 2-butanol.

Ether compounds:
For example, alkylene glycol alkyl ethers (ethylene glycol monomethyl ether, diethyl ether, diisopropyl ether, dibutyl ether, tetrahydrofuran, and dioxane are mentioned.

Amino compounds:
An example is triethylamine.

Ketone compounds:
Examples include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.

Carbonate compounds:
Examples thereof include dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate.

Aromatic compounds:
Examples thereof include benzene and toluene.

Ester compounds:
Examples include ethyl acetate, propyl acetate, butyl acetate, ethyl formate, propyl formate, and butyl formate.

Aliphatic compounds:
Examples include pentane, hexane, heptane, octane, and cyclohexane.

Nitrile compounds:
For example, acetonitrile and propylonitrile are mentioned.

  The solvent having a boiling point of less than 120 ° C. in the above (e1) preferably has a boiling point of 50 ° C. or more, and more preferably 70 ° C. or more. The solvent having a boiling point of less than 120 ° C preferably has a boiling point of 100 ° C or lower.

As the solvent in the above (e1), one kind of solvent having a boiling point of less than 120 ° C. may be used alone, or two or more kinds may be used in combination.
The solvent having a boiling point of less than 120 ° C. in the above (e1) is preferably at least one selected from the group consisting of an ether compound, a carbonate compound, a ketone compound and a hydrocarbon compound.
The difference in boiling point between the solvent (b1) having a boiling point of 150 to 300 ° C and the solvent (e1) having a boiling point of less than 120 ° C is preferably 30 ° C or more, more preferably 50 to 180 ° C, 80-170 degreeC is further more preferable, and 100-160 degreeC is further more preferable.
Moreover, in the manufacturing method of the all-solid-state secondary battery of this invention, the temperature which dries the composition apply | coated on metal foil is 30 degreeC or more lower than the boiling point of the solvent whose boiling point is 150-300 degreeC in said (b1). Is preferred. The drying temperature is preferably 5 ° C. or more higher than the boiling point of the solvent having a boiling point of less than 120 ° C. in the above (e1).
The drying time is not particularly limited as long as the solvent having a boiling point of less than 120 ° C. can be volatilized, and is usually 1 minute to 10 hours.

  Examples of the method for applying the composition onto the metal foil include wet coating, spray coating, spin coating, slit coating, stripe coating, and bar coating dip coating, and wet coating is preferable.

[Electrode sheet for all-solid-state secondary battery]
The electrode sheet for an all-solid-state secondary battery of the present invention (hereinafter simply referred to as “electrode sheet of the present invention”) is formed on the above-described metal foil that can function as a current collector (a) to (d). It is an electrode sheet having a layer satisfying the above condition, and can be suitably used for the all solid state secondary battery of the present invention. In the electrode sheet of the present invention, the layer directly provided on the metal foil is a negative electrode active material layer or a positive electrode active material layer.
More specifically, the electrode sheet of the present invention includes the following aspects.

(I) A laminated sheet having a two-layer structure comprising a metal foil and the above-described negative electrode active material layer or positive electrode active material layer, wherein the negative electrode active material layer or positive electrode active material layer provided on the metal foil layer is the above An aspect satisfying (a) to (d).
(II) A laminated sheet having a three-layer structure in which a metal foil, the above-described negative electrode active material layer or positive electrode active material layer, and a solid electrolyte layer are laminated in this order, and two layers provided on the metal foil ( A mode in which at least one of the electrode layer and the solid electrolyte layer) satisfies the above (a) to (d).
(III) A laminated sheet having a four-layer structure in which a metal foil, the above-described negative electrode active material layer or positive electrode active material layer, solid electrolyte layer, and positive electrode active material layer or negative electrode active material layer are laminated in this order. A mode in which at least one of the three layers (electrode layer, solid electrolyte layer and electrode layer) provided on the metal foil satisfies the above (a) to (d). Note that one of the two electrode layers facing each other across the solid electrolyte layer is a negative electrode active material layer, and the other is a positive electrode active material layer.

  The configuration and layer thickness of each layer constituting the electrode sheet of the present invention are the same as the configuration and layer thickness of each layer described in the all solid state secondary battery of the present invention.

[Preparation of electrode sheet for all-solid-state secondary battery]
In the method for producing an electrode sheet of the present invention, a composition (slurry) satisfying the above-described (a1) to (e1) is applied onto a metal foil functioning as a current collector, dried, and a solvent having a boiling point of less than 120 ° C. Volatilizing the solvent (e1). Preferred drying conditions are the same as the preferred drying conditions described in the above-described method for producing an all-solid secondary battery.

  In the method for producing an electrode sheet of the present invention, “a composition satisfying (a1) to (e1) is applied onto a metal foil and dried to volatilize a solvent having a boiling point of less than 120 ° C. (the solvent of the above (e1)). "Means to include the following embodiments (i) to (vi).

(I) A composition satisfying the above (a1) to (e1) and containing a negative electrode active material is directly applied on a metal foil, dried to volatilize a solvent having a boiling point of less than 120 ° C., and a negative electrode on the metal foil. An embodiment in which an active material layer is formed.
(Ii) A composition satisfying the above (a1) to (e1) and containing a positive electrode active material is directly applied on a metal foil, dried to volatilize a solvent having a boiling point of less than 120 ° C., and a positive electrode on the metal foil. An embodiment in which an active material layer is formed.
(Iii) A composition satisfying the above (a1) to (e1) is directly applied on the negative electrode active material layer of the laminate having a two-layer structure comprising the metal foil and the negative electrode active material layer, and dried to have a boiling point of 120 ° C. A mode in which less than the solvent is volatilized to form a solid electrolyte layer on the negative electrode active material layer.
(Iv) A composition satisfying the above (a1) to (e1) is directly applied on a positive electrode active material layer of a laminate having a two-layer structure comprising a metal foil and a positive electrode active material layer, and dried to have a boiling point of 120 ° C. A mode in which less than the solvent is volatilized to form a solid electrolyte layer on the positive electrode active material layer.
(V) A composition satisfying the above (a1) to (e1) and containing a positive electrode active material directly on a solid electrolyte layer of a laminate having a three-layer structure comprising a metal foil, a negative electrode active material layer, and a solid electrolyte layer A mode in which a positive electrode active material layer is formed on the solid electrolyte layer by coating and drying to volatilize a solvent having a boiling point of less than 120 ° C.
(Vi) A composition satisfying the above (a1) to (e1) and containing a negative electrode active material directly on a solid electrolyte layer of a laminate having a three-layer structure comprising a metal foil, a positive electrode active material layer, and a solid electrolyte layer A mode in which a negative electrode active material layer is formed on the solid electrolyte layer by coating and drying to volatilize a solvent having a boiling point of less than 120 ° C.

In the embodiment (iii), the negative electrode active material layer may or may not satisfy the above (a) to (d).
In the aspect (iv), the positive electrode active material layer may or may not satisfy the above (a) to (d).
In the aspect (v), the negative electrode active material layer and the solid electrolyte layer may or may not satisfy the above (a) to (d).
In the aspect (vi), the positive electrode active material layer and the solid electrolyte layer may or may not satisfy the above (a) to (d).

In the above aspects (i) and (ii), a solid electrolyte layer is formed on the outermost negative electrode active material layer and the positive electrode active material layer, and in the aspect (i), the positive electrode active material layer, In the embodiment, the all-solid-state secondary battery of the present invention can be obtained by forming a negative electrode active material layer and further stacking a metal foil that can function as a collector electrode.
Further, in the above aspects (iii) and (iv), on the outermost solid electrolyte layer, a positive electrode active material layer in the aspect (iii), a negative electrode active material layer in the aspect (iv), Furthermore, if the metal foil which can function as a collector electrode is piled up, the all-solid-state secondary battery of this invention can be obtained.
Further, in the above aspects (v) and (vi), a metal foil that can function as a collector electrode is stacked on the positive electrode active material layer and the negative electrode active material layer on the outermost surface to form a laminate having a five-layer structure. Thus, the all solid state secondary battery of the present invention can be obtained.

[Use of all-solid 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, a pen input personal computer, a mobile personal computer, an electronic book player, a mobile phone, a cordless phone, a pager, a handy terminal, a mobile fax machine, a mobile phone Copy, portable printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, minidisc, electric shaver, walkie-talkie, 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.

  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, “part” and “%” representing the composition are based on mass unless otherwise specified. In addition, “-” used in the table means that it does not have the composition of the column.

Reference Example 1 Preparation of Solid Electrolyte Composition (S-1) 180 zirconia beads having a diameter of 5 mm were put into a 45 mL container (manufactured by Fritsch) made of zirconia, and 2.1 g of LiTFSI as a metal salt of (a1). , 0.4 g of propylene carbonate as a high boiling point solvent of (b1), LLZ (Li ₇ La ₃ Zr ₂ O ₁₂ lithium lanthanum zirconate, volume average particle size 5.06 μm, Toshima Seisakusho Co., Ltd. as an inorganic solid electrolyte of (c1) Made) and 17.0 g of dimethyl carbonate as a dispersion medium. Then, said container was set to the planetary ball mill made from a Fritsch company, and it mixed for 1 hour at the rotation speed of 100 rpm, and prepared the solid electrolyte composition (S-1).

Reference Example 2 Preparation of Solid Electrolyte Composition (S-2 to S-14, T-1, T-2) In Reference Example 1, the types and blending amounts of the compounds corresponding to (a1) to (c1) are as follows. Reference Example 1 except that the binder is blended as described in Table 1, and if necessary, the binder is blended as described in Table 1, and the solvent (dispersion medium) corresponding to (e1) is blended as described in Table 1. Similarly, solid electrolyte compositions (S-2 to S-14, T-1, and T-2) were prepared.
The abbreviations listed in Table 1 will be described below.

・ LLT: Li _0.33 La _0.55 TiO ₃ (manufactured by Toshima Seisakusho)
・ LLZ: Li ₇ La ₃ Zr ₂ O ₁₂ (manufactured by Toshima Seisakusho)
-LiTFSI: Lithium bis (trifluoromethanesulfonyl) imide (manufactured by Wako Pure Chemical Industries, Ltd.)
LPS: Li-PS-based glass synthesized below PC: Propylene carbonate (manufactured by Wako Pure Chemical Industries, Ltd.)
・ FEC: Fluoroethylene carbonate (Kishida Chemical Co., Ltd.)
BN: benzonitrile (manufactured by Wako Pure Chemical Industries)
DMC: Dimethyl carbonate (Wako Pure Chemical Industries, Ltd.)
-B-1: Acrylic particle A preparation method is shown below.
・ B-2: Polyvinylidene difluoride (Manufacturer: ARKEMA, trade name: KYNAR301F)
-B-3: Urethane particle A preparation method is shown below.

<Synthesis of sulfide-based inorganic solid electrolyte>
-Synthesis of Li-PS-based glass-
As a sulfide-based inorganic solid electrolyte, T.I. Ohtomo, A .; Hayashi, M .; Tatsumisago, Y. et al. Tsuchida, S .; HamGa, 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, a Li—PS glass was synthesized.

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%), 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. The mixing ratio of Li ₂ S and P ₂ S ₅ was Li ₂ S: P ₂ S ₅ = 75: 25 in terms of molar ratio.
66 zirconia beads having a diameter of 5 mm were introduced into a 45 mL container (manufactured by Fritsch) made of zirconia, the whole mixture of lithium sulfide and phosphorous pentasulfide was introduced, and the container was sealed under an argon atmosphere. This container is set in a planetary ball mill P-7 (trade name) manufactured by Frichtu, and mechanical milling is performed at a temperature of 25 ° C. and a rotation speed of 510 rpm for 20 hours to obtain a yellow powder sulfide solid electrolyte (Li-PS system). 6.20 g of glass) was obtained.

<Preparation of acrylic resin B-1>
-Synthesis of macromonomer (M-1)-
190 parts by mass of toluene was added to a 1 L three-necked flask equipped with a reflux condenser and a gas introduction cock, and nitrogen gas was introduced at a flow rate of 200 mL / min for 10 minutes, followed by heating to 80 ° C. The liquid mixture A prepared by the following prescription was dripped in another container over 2 hours, and it stirred at 80 degreeC after that for 2 hours. Thereafter, 0.2 g of V-601 was added, and the mixture was further stirred at 95 ° C. for 2 hours. 0.025 parts by mass of 2,2,6,6-tetramethylpiperidine-1-oxyl (manufactured by Tokyo Chemical Industry Co., Ltd.) and glycidyl methacrylate (Wako Pure Chemical Industries, Ltd.) were added to the above reaction solution maintained at 95 ° C. after stirring. 13 parts by mass of Kogyo Kogyo Co., Ltd. and 2.5 parts by mass of tetrabutylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) were added and stirred at 120 ° C. for 3 hours in the atmosphere. After cooling to room temperature, it was added to methanol for precipitation, and the resulting precipitate was washed twice with methanol and then blown dry at 50 ° C. The obtained solid was dissolved in 300 parts by mass of heptane to obtain a macromonomer (M-1) solution (hereinafter referred to as a monomer heptane solution). The solid content concentration of the macromonomer (M-1) was 43.4% by mass, the mass average molecular weight was 16,000, and the SP value which is a solubility parameter was 9.1.

(Prescription of mixture A)
Dodecyl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd.) 150 parts by mass Methyl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd.) 59 parts by mass 3-mercaptoisobutyric acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 2 parts by mass V-601 ( Wako Pure Chemical Industries, Ltd.) 1.9 parts by mass

− Synthesis of acrylic resin B-1 −
After adding 47 parts by mass of the monomer heptane solution prepared above and 60 parts by mass of heptane to a 1 L three-necked flask equipped with a reflux condenser and a gas introduction cock, nitrogen gas was introduced at a flow rate of 200 mL / min for 10 minutes. The temperature was raised to 80 ° C. Mixed solution B prepared in a separate container [93 parts by mass of the heptane solution of the monomer prepared above, 100 parts by mass of butyl acrylate (manufactured by Wako Pure Chemical Industries, Ltd.), methyl methacrylate (Wako Pure Chemical Industries, Ltd.) 20 parts by mass), 20 parts by mass of acrylic acid (manufactured by Wako Pure Chemical Industries, Ltd.), and 1.1 parts by mass of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.)] over 2 hours. The solution was added dropwise and then stirred at 80 ° C. for 2 hours. Thereafter, 0.2 g of V-601 was added, and the mixture was further stirred at 95 ° C. for 2 hours. After cooling to room temperature, 300 mL of heptane was added and filtered to obtain a dispersion of acrylic resin B-1.

<Preparation of urethane resin B-3>
In order to synthesize urethane resin B-3, polyurea colloidal particles Aa-1 were first synthesized.
Specifically, a terminal diol-modified polydodecyl methacrylate (Ab-1: a diol compound having a long-chain alkyl group having 6 or more carbon atoms) 25% by mass of a heptane solution 260 g was added to a 1 L three-necked flask, and heptane was added. Diluted with 110 g. To this were added 11.1 g of isophorone diisocyanate (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.1 g of Neostan U-600 (trade name, manufactured by Nitto Kasei Co., Ltd.), and the mixture was heated and stirred at 75 ° C. for 5 hours. Thereafter, a diluted solution of 125 g of heptane of 0.4 g of isophoronediamine (amine compound) was dropped over 1 hour. The polymer solution changed from a transparent solution to a pale yellow fluorescent color 10 minutes after the start of dropping. It was confirmed that a urea colloid was formed by this change. The reaction solution was cooled to room temperature to obtain 506 g of a 15 mass% heptane solution of polyurea colloidal particles Aa-1.
In the polyurea colloidal particle Aa-1, the dodecyl group of the terminal diol-modified polydodecyl methacrylate is a structural part solvated with heptane (hydrocarbon solvent), and the polyurea structure is a structural part that is not solvated with heptane.
The mass average molecular weight of the polyurea of the polyurea colloidal particles Aa-1 was 9,600.

Next, urethane resin B-3 was synthesized using polyurea colloidal particles Aa-1.
Specifically, 2.6 g of dicyclohexylmethane diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.42 g of 1,4-butanediol (manufactured by Wako Pure Chemical Industries, Ltd.), 2,2-bis (hydroxymethyl) butane in a 50 mL sample bottle 0.28 g of acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and 2.9 g of Kuraray polyol P-1020 (trade name, manufactured by Kuraray Co., Ltd.) were added. To this was added 15.7 g of a 15 mass% heptane solution of polyurea colloidal particles Aa-1, and the mixture was dispersed with a homogenizer for 30 minutes while heating at 50 ° C. During this time, the mixture became fine particles and became a light orange slurry. The obtained slurry was put into a 100 mL three-necked flask heated in advance to a temperature of 80 ° C., Neostan U-600 (trade name, manufactured by Nitto Kasei Co., Ltd.) 0.1 g was added, and the temperature was 80 ° C. and the rotation speed was 400 rpm. Stir for hours. The slurry became a white emulsion. From this, it was estimated that polyurethane particles were formed. The white emulsion slurry was cooled to obtain a 40 mass% heptane dispersion of urethane particles B-3.

Reference Example 3 Production of Solid Electrolyte Sheet The solid electrolyte composition (S-1) was applied onto an aluminum foil having a thickness of 20 μm using an applicator with adjustable clearance, heated at 80 ° C. for 1 hour, and then further 120 The dispersion medium of (e1) was dried by heating at 0 ° C. for 1 hour. Then, using a heat press machine, it pressurized (10 MPa, 1 minute), heating (80 degreeC). 101 solid electrolyte sheet was obtained.
Except for changing the solid electrolyte composition (S-1) to the solid electrolyte compositions (S-2) to (S-14), (T-1), and (T-2) shown in Table 1 above, the sample No. In the same manner as the solid electrolyte sheet of No. 101, Sample No. Solid electrolyte sheets of 102 to 114 and c11 and 12 were produced. In preparing c12, drying was performed only at 60 ° C. for 10 minutes, and acetone was volatilized to leave a certain amount of DMC.
Sample No. The film thicknesses of the solid electrolyte layers 101 to 114 and c11 were 50 μm. Sample No. The film thickness of the solid electrolyte layer of c12 was 200 μm.

  Using each of the solid electrolyte sheets prepared above, binding properties, ionic conductivity, and flammability were evaluated.

[Test Example 1] Evaluation of binding property The solid electrolyte layer of the solid electrolyte sheet produced above was cut into a rectangular shape having a length of 50 mm and a width of 12 mm, and a cello tape (registered trademark, manufactured by Nichiban Co., Ltd.) having a width of 12 mm and a length of 60 mm was used. The film was peeled off by 50 mm at a speed of 10 mm / min. In that case, it evaluated by the area ratio of the sheet | seat part which peeled with respect to the area of the peeled-off cellotape. Measurement was performed on 10 samples prepared with the same formulation (that is, a total of 10 measurements), and an average of 8 measurement values excluding the maximum value and the minimum value was adopted.
The obtained value was evaluated based on the following evaluation criteria. The results are shown in the table below.

(Evaluation criteria)
4: The area ratio of the peeled sheet part is 5% or more and less than 15% 3: The area ratio of the peeled sheet part is 15% or more and less than 30% 2: The area ratio of the peeled sheet part is 30% or more and less than 60% 1: The area ratio of the peeled sheet part is 60% or more

[Test Example 2] Evaluation of ion conductivity Each solid electrolyte sheet prepared above was cut into a disk shape having a diameter of 14.5 mm, and the aluminum foil cut into a disk shape having a diameter of 15 mm was brought into contact with the solid electrolyte layer, and spacers were formed. And washer was put into a stainless steel 2032 type coin case. As shown in FIG. 2, a binding pressure (screw tightening pressure: 8N) was applied from the outside of the coin case to produce an ion conductivity measurement cell.

The ion conductivity was measured using each ion conductivity measurement cell obtained above. Specifically, in a constant temperature bath at 30 ° C., AC impedance was measured from 1 MHz to 1 Hz with a voltage amplitude of 5 mV using 1255B FREQUENCY RESPONSE ANALYZER (trade name) manufactured by SOLARTRON. Thereby, the resistance in the film thickness direction of the sample was obtained, and the ionic conductivity was obtained by the following formula. The results are shown in the table below.

Ionic conductivity (mS / cm) =
1000 × sample film thickness (cm) / (resistance (Ω) × sample area (cm ² ))

[Test Example 3] Evaluation of flammability The solid electrolyte layer of each solid electrolyte sheet produced as described above was brought into contact with the internal flame of a butane gas burner adjusted to a total flame length of 2 cm for 3 seconds, and the flame was released. Flammability was evaluated based on the presence or absence of flammability.

As shown in Table 2, the solid electrolyte sheet of sample c11 in which the solid electrolyte layer does not contain components (a) and (b) results in inferior binding between the solid electrolyte particles, and ion conductivity can also be detected. There wasn't. In sample c12 containing a large amount of a solvent other than component (b) in the solid electrolyte layer, the solid electrolyte layer was flammable, resulting in poor safety.
On the other hand, the samples 101 to 114 in which the solid electrolyte layer satisfies the provisions (a) to (d) of the present invention have good binding properties between the solid electrolyte particles and exhibited excellent ionic conductivity.

[Example, Comparative Example] Production of electrode sheet for all-solid-state secondary battery An electrode sheet for all-solid-state secondary battery and an all-solid-state secondary battery were produced as follows.

<Preparation of composition for positive electrode>
180 pieces of zirconia beads having a diameter of 5 mm are put into a 45 mL container (manufactured by Fritsch) made of zirconia, 6 parts by mass of the positive electrode active material NMC, 0.45 parts by mass of LiTFSI of (a1), and high boiling point of (b1) 0.09 parts by mass of propylene carbonate as a solvent, and 4 masses of LLZ (Li ₇ La ₃ Zr ₂ O ₁₂ lithium lanthanum zirconate, volume average particle size 5.06 μm, manufactured by Toshima Seisakusho Co., Ltd.) as the inorganic solid electrolyte of (c1) Part, 18.0 g of dimethyl carbonate was added as a low boiling point solvent (dispersion medium) of (e1). Thereafter, the above container was set on a planetary ball mill manufactured by Fritsch, and mixed for 1 hour at a rotational speed of 100 rpm. The composition for positive electrodes used for 201 was prepared.
Sample No. shown in the following table was the same as above except that the type of the positive electrode active material and solid electrolyte used and the amount of propylene carbonate used were changed as shown in the following table. The composition for positive electrodes used for 202-206, c21, and 22 was prepared. Sample No. LiTFSI and propylene carbonate are not blended in the positive electrode composition corresponding to c21.

<Preparation of negative electrode composition>
180 pieces of zirconia beads having a diameter of 5 mm are put into a 45 mL container (made by Fritsch) made of zirconia, 6 parts by mass of graphite as a negative electrode active material, 0.45 parts by mass of LiTFSI as a metal salt of (a1), (b1) 0.09 parts by mass of propylene carbonate as a high boiling point solvent, and LLZ (Li ₇ La ₃ Zr ₂ O ₁₂ lithium lanthanum zirconate, volume average particle size 5.06 μm, manufactured by Toyoshima Seisakusho) as an inorganic solid electrolyte of (c1) 4 parts by mass, 18.0 g of dimethyl carbonate was added as a low boiling point solvent (dispersion medium) of (e1). Thereafter, the above container was set on a planetary ball mill manufactured by Fritsch, and mixed for 1 hour at a rotational speed of 100 rpm. A negative electrode composition used for 201 was prepared.
In the same manner as described above except that the type of the negative electrode active material and the solid electrolyte used and the amount of propylene carbonate used were changed as shown in the table below, Sample No. Negative electrode compositions used for 202 to 206, c21 and 22 were prepared. Sample No. LiTFSI and propylene carbonate are not blended in the negative electrode composition corresponding to c21.
The abbreviations listed in the table below are described below.
NMC: Li (Ni _1/3 Mn _1/3 Co _1/3 ) O ₂ nickel, manganese, lithium cobaltate LCO: LiCoO ₂ lithium cobaltate LTO: Li ₄ Ti ₅ O ₁₂

<Preparation of electrode sheet for all-solid-state secondary battery>
Each positive electrode composition obtained above was applied onto an aluminum foil having a thickness of 20 μm by an applicator and dried at 120 ° C. for 2 hours to volatilize and remove the dispersion medium of (e1). Then, it pressurized (10 Pa, 1 minute), heating (80 degreeC) using the heat press machine. Thus, the sample No. shown in the table below. The positive electrode active material layer corresponding to 201-206 and c21 was formed, and each electrode sheet of the two-layer laminated structure which consists of a positive electrode collector and a positive electrode active material layer was produced. In each two-layer electrode sheet, the thickness of the positive electrode active material layer was 150 μm.
Sample No. For the positive electrode active material layer corresponding to c22, in the formation of the positive electrode active material layer, drying at 120 ° C. for 2 hours was changed to 60 ° C. for 10 minutes, and heating and pressurization with a heat press machine were performed. There wasn't. That is, sample no. DMC was left in the positive electrode layer corresponding to c22. Sample No. The thickness of the positive electrode active material layer corresponding to c22 was 180 μm.

On the positive electrode active material layer of each of the two-layer laminate electrode sheets prepared above, the solid electrolyte composition shown in the following table, which was prepared in Reference Example 2, was applied using an applicator. Thereafter, drying was performed at 120 ° C. for 2 hours, and the dispersion medium (e1) was volatilized and removed. Thus, the sample No. shown in the table below. An electrode sheet having a three-layer structure composed of a positive electrode current collector, a positive electrode active material layer, and a solid electrolyte layer corresponding to 201 to 206 and c21 was produced.
Sample No. For the solid electrolyte layer corresponding to c22, acetone was volatilized by changing the drying at 120 ° C. for 2 hours to 60 ° C. for 10 minutes in the preparation of the electrode sheet having the above three-layer structure. That is, sample no. DMC remains in the solid electrolyte layer corresponding to c22.

The negative electrode composition prepared above was applied onto the solid electrolyte layer of each of the three-layered electrode sheets prepared above, dried at 120 ° C. for 2 hours, and the dispersion medium (e1) was volatilized and removed. . Then, it pressurized (10 MPa, 1 minute), heating (80 degreeC) using the heat press machine. Thus, the sample No. shown in the table below. Electrode sheets having a four-layer structure composed of a positive electrode current collector, a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer corresponding to 201 to 206 and c21 were produced.
Sample No. Regarding the formation of the negative electrode layer corresponding to c22, in the production of the electrode sheet having the above three-layer structure, the drying at 120 ° C. for 2 hours was changed to 60 ° C. for 10 minutes, and heating and pressurization with a heat press machine were performed. Was not implemented. That is, sample no. DMC remains in the negative electrode layer corresponding to c22. In the obtained electrode sheet having a four-layer laminated structure, the thickness of the solid electrolyte composition layer was measured according to Sample No. Each of the solid electrolyte composition layers corresponding to 201 to 206 and c21 is 50 μm. The solid electrolyte composition layer corresponding to c22 was 200 μm. The thickness of the negative electrode active material layer is the same as that of Sample No. The negative electrode active material layers corresponding to 201 to 206 and c21 are all 120 μm. The negative electrode active material layer corresponding to c22 was 140 μm.

  Using the electrode sheet having a four-layer structure produced as described above, binding property, ion conductivity and flammability were evaluated.

[Test Example 4] Evaluation of Bindability In Test Example 1, the same procedure as in Test Example 1 was conducted, except that the object to which the cellophane was applied was changed to the negative electrode active material layer of the electrode sheet having the four-layer laminated structure. Wearability was evaluated. The results are shown in the table below.

[Test Example 5] Evaluation of ion conductivity The electrode sheet having the four-layer structure prepared above was cut into a disk shape having a diameter of 14.5 mm, and a copper foil having a thickness of 20 μm cut into a disk shape having a diameter of 15 mm was used as a negative electrode active material. The all-solid-state secondary battery was manufactured by contacting the top of the layer, incorporating a spacer and washer, and placing it in a stainless steel 2032 type coin case. A constraining pressure (screw tightening pressure: 8N) was applied from the outside of the coin case to produce an all-solid secondary battery for ion conductivity measurement. Using this all solid state secondary battery for ion conductivity measurement, the ion conductivity was measured in the same manner as in Test Example 2. The results are shown in the table below.

[Test Example 6] Evaluation of flammability After the inner flame of a butane gas burner adjusted to a total flame length of 2 cm was brought into contact with the negative electrode active material layer of the electrode sheet having a four-layer structure prepared above for 3 seconds, and the flame was released. The flammability was evaluated based on the presence or absence of ignition of the negative electrode active material layer. The results are shown in the table below.

  As shown in Table 3 above, the electrode sheet satisfying (a) to (d) defined in the present invention by the electrode layer and the solid electrolyte layer has good binding properties in the layer of the solid electrolyte or active material, It turned out that the all-solid-state secondary battery produced using this electrode sheet shows the outstanding ion conductivity. Moreover, the electrode sheet which satisfies (a)-(d) which an electrode layer prescribes | regulates by this invention did not ignite, and was excellent also in safety.

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 (4)

A method for producing an all-solid secondary battery having a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer in this order, wherein a composition satisfying the following (a1) to (e1) is applied on a metal foil, A method for producing an all-solid secondary battery, comprising: drying and volatilizing a solvent having a boiling point of less than 120 ° C. to form at least one of the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer. .
(A1) A metal salt belonging to Group 1 or Group 2 of the Periodic Table and containing a metal salt having ionic conductivity.
(B1) A solvent having a boiling point of 150 to 300 ° C. is contained, and the content of the solvent having a boiling point of 150 to 300 ° C. is 0.2 to 10% by mass in the solid content of the composition.
(C1) An inorganic solid electrolyte having conductivity of ions of metals belonging to Group 1 or Group 2 of the periodic table is contained.
(D1) The ratio of the content of the metal salt of (a1) to the content of the solvent of (b1) is a molar ratio of [content of metal salt] / [content of solvent] = 1.0 / 0.1-1.0 / 5.0.
(E1) A solvent having a boiling point of less than 120 ° C. is contained, and the content of the solvent having a boiling point of less than 120 ° C. is 20 to 80% by mass in the composition. The manufacturing method of the electrode sheet for all-solid-state secondary batteries including apply | coating the composition which satisfy | fills following (a1)-(e1) on metal foil, and drying and volatilizing the solvent below boiling point 120 degreeC.
(A1) A metal salt belonging to Group 1 or Group 2 of the Periodic Table and containing a metal salt having ionic conductivity.
(B1) A solvent having a boiling point of 150 to 300 ° C. is contained, and the content of the solvent having a boiling point of 150 to 300 ° C. is 0.2 to 10% by mass in the solid content of the composition.
(C1) An inorganic solid electrolyte having conductivity of ions of metals belonging to Group 1 or Group 2 of the periodic table is contained.
(D1) The ratio of the content of the metal salt of (a1) to the content of the solvent of (b1) is a molar ratio of [content of metal salt] / [content of solvent] = 1.0 / 0.1-1.0 / 5.0.
(E1) A solvent having a boiling point of less than 120 ° C. is contained, and the content of the solvent having a boiling point of less than 120 ° C. is 20 to 80% by mass in the composition. An all-solid secondary battery composition that satisfies the following (a1) to (e1).
(A1) A metal salt belonging to Group 1 or Group 2 of the Periodic Table and containing a metal salt having ionic conductivity.
(B1) A solvent having a boiling point of 150 to 300 ° C. is contained, and the content of the solvent having a boiling point of 150 to 300 ° C. is 0.2 to 10% by mass in the solid content of the composition.
(C1) An inorganic solid electrolyte having conductivity of ions of metals belonging to Group 1 or Group 2 of the periodic table is contained.
(D1) The ratio of the content of the metal salt of (a1) to the content of the solvent of (b1) is a molar ratio of [content of metal salt] / [content of solvent] = 1.0 / 0.1-1.0 / 5.0.
(E1) A solvent having a boiling point of less than 120 ° C. is contained, and the content of the solvent having a boiling point of less than 120 ° C. is 20 to 80% by mass in the composition. The composition for an all-solid-state secondary battery according to claim 3 , which is used for forming a layer satisfying the following (a) to (d).
(A) A metal salt belonging to Group 1 or Group 2 of the Periodic Table and containing a metal salt having ionic conductivity.
(B) 0.2-10 mass% of solvent with a boiling point of 150-300 degreeC is contained.
(C) It contains an inorganic solid electrolyte having conductivity of metal ions belonging to Group 1 or Group 2 of the Periodic Table.
(D) The ratio of the content of the metal salt of (a) to the content of the solvent of (b) is a molar ratio of [content of metal salt] / [content of solvent] = 1.0 / 0.1-1.0 / 5.0.

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