JP2021163758A - Method for producing solid electrolyte - Google Patents

Abstract

To provide a method for homogeneously and easily producing a compound with cubic system algyrodite type crystal structure in which water durability is improved to suppress generation of H2S, and decrease in ionic conductivity is suppressed.SOLUTION: Provided is a method for producing solid electrolyte that includes a step of mixing (A) a sulfide containing lithium atom, phosphorus atom and sulfur atom and having algyrodite type crystal structure, and (B) phosphorus sulfide in the presence of at least one solvent selected from non-polar solvents and aprotic solvents without using a crusher, and a step of removing the solvent.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing a solid electrolyte.

With the rapid spread of information-related devices such as personal computers, video cameras, and mobile phones and communication devices in recent years, the development of batteries used as their power sources has been emphasized. Conventionally, an electrolytic solution containing a flammable organic solvent has been used in a battery used for such an application, but by solidifying the battery, a flammable organic solvent is not used in the battery, and a safety device is used. An all-solid-state battery has been developed in which the electrolytic solution is replaced with a solid electrolyte layer because the above can be simplified and the manufacturing cost and productivity are excellent.

This solid electrolyte is required to have high ionic conductivity and be chemically stable.
From the viewpoint of improving ionic conductivity, it has been known to use a compound having a cubic argyrodite type crystal structure containing a lithium atom, a phosphorus atom and a sulfur atom (Patent Document 1). However, since compounds having a cubic algyrodite crystal structure have extremely high reactivity with water and oxygen, they have problems in industrial use, such as having to be handled under an inert gas with an ultra-low dew point. Was.

For this reason, it has been disclosed that the composition of a compound having a cubic algyrodite type crystal structure is examined for the purpose of improving the chemical stability (Patent Document 1), but the method described in Patent Document 1 So, by the water resistance touch it be dry air without sufficient generates hydrogen sulfide (H 2 _S), ionic conductivity is a problem of a decrease.
In order to improve this, coating a solid electrolyte composed of a compound having a cubic algyrodite type crystal structure has been studied (Patent Document 2).

Japanese Unexamined Patent Publication No. 2016-24874 International Publication No. 2018/003333 Pamphlet

As a result of studies by the present inventors, it is effective to coat a compound having a cubic algyrodite type crystal structure from the viewpoint of water resistance, but as described in Patent Document 2, a cubic algyrodite type crystal in the method of mixing and grinding the powder and P ₂ S ₅ powder having a structure, a reaction between solids, it has been found that it is difficult to obtain a homogeneous solid electrolyte material.
Further, since the powder is crushed and mixed for a long time, a high energy investment is required in the process, which is not preferable from the viewpoint of reducing greenhouse gas (GHG) emissions.
Furthermore, in the formation of a coating by pulverization and mixing, the surface of the solid electrolyte may be amorphous due to the shear energy generated in the system. Therefore, a heating step is required as the next step. However, it was also found that it is necessary to improve the production method because granulation occurs in the process of crystallization when this heating step is performed.

An object of the present invention, generation of granulation and H _{2 S} is suppressed, it is to provide a method for producing a compound having a cubic Arujirodaito type crystal structure reduced is suppressed in the ion conductivity.

As a result of diligent studies to solve the above problems, the present inventor has found the following matters and has completed the present invention.
1. 1. Later described embodiments of the present invention (hereinafter sometimes referred to as "embodiment".) The solid electrolyte prepared by the the generation of H _{2 S} be exposed to moisture and the like can be suppressed.
2. By performing the above treatment in the presence of at least one solvent selected from a non-polar solvent and an aprotic solvent, no subsequent heating step is required, so that granulation does not occur and the particle size is kept small. Further, by treating in at least one solvent selected from a non-protic solvent and an aprotic solvent, a solid-liquid reaction occurs, so that a homogeneous solid electrolyte can be obtained.
3. 3. Since it is carried out in at least one solvent selected from a non-polar solvent and an aprotic solvent, a solid electrolyte can be obtained without the need for special manufacturing equipment and excessive energy input.

That is, the present invention provides the following [1] to [13].
[1] In the presence of at least one solvent selected from a non-polar solvent and an aprotic solvent, (A) a sulfide containing a lithium atom, a phosphorus atom and a sulfur atom and having an algyrodite type crystal structure and (B). The process of mixing phosphorus sulfide without using a crusher, and
A drying step of removing the solvent and
A method for producing a solid electrolyte.
The method for producing a solid electrolyte according to [1], wherein [2] is carried out in at least one solvent selected from a non-polar solvent and an aprotic solvent.
[3] The method for producing a solid electrolyte according to [1] or [2], wherein the (B) phosphorus sulfide is diphosphorus pentasulfide.

[4] The method for producing a solid electrolyte according to any one of [1] to [3], wherein heating is performed in the mixing step.
[5] The method for producing a solid electrolyte according to [4], wherein the heating in the mixing step is performed at a temperature of less than 100 ° C.
[6] The amount of phosphorus (B) added to 100.0 parts by mass of (A) sulfide in the mixing step is 0.5 parts by mass or more and 30.0 parts by mass or less, [1] to [5]. The method for producing a solid electrolyte according to any one of.

[7] At least one solvent selected from the non-polar solvent and the aprotonic solvent is one or more selected from the group consisting of saturated hydrocarbons, unsaturated hydrocarbons and aromatic hydrocarbons, [1] to The method for producing a solid electrolyte according to any one of [6].
[8] The method for producing a solid electrolyte according to any one of [1] to [7], wherein at least one solvent selected from the non-polar solvent and the aprotic solvent is toluene, xylene or heptane.
[9] The method for producing a solid electrolyte according to any one of [1] to [8], wherein the sulfide (A) further contains a halogen atom.

[10] The method for producing a solid electrolyte according to [9], wherein the halogen atom is one or more selected from the group consisting of a chlorine atom or a bromine atom.
[11] The method for producing a solid electrolyte according to any one of [1] to [10], wherein (A) sulfide and (B) phosphorus sulfide are used without being pulverized.
[12] The method for producing a solid electrolyte according to any one of [1] to [11], wherein heating to 200 ° C. or higher is not performed after the drying step.
[13] The method for producing a solid electrolyte according to any one of [1] to [12], which does not use a medium-type crusher.

According to the present invention, generation of granulation and H _{2 S} is suppressed, it is possible to provide a method for producing a compound having a cubic Arujirodaito type crystal structure to suppress the decrease in ionic conductivity.

Conceptual diagram of the test device (exposure test device 1) used in the exposure test

Hereinafter, this embodiment will be described. The embodiments described below are merely one embodiment of the method for producing a solid electrolyte of the present invention, and the present invention is not limited thereto.
Further, in the present specification, lithium shall mean both lithium and lithium ions, and shall be interpreted as appropriate as long as there is no technical contradiction.
In the present specification, the upper and lower limit numerical values relating to the numerical ranges of "greater than or equal to", "less than or equal to", and "to" are numerical values that can be arbitrarily combined, and the numerical values of Examples are used as the upper and lower limit numerical values. You can also do it. In addition, the preferred provisions can be arbitrarily adopted. That is, one preferred provision can be adopted in combination with one or more other preferred provisions. It can be said that the combination of preferable ones is more preferable.

[Manufacturing method of solid electrolyte]
In this embodiment, in the presence of at least one solvent selected from a non-polar solvent and an aprotonic solvent, (A) a sulfide containing a lithium atom, a phosphorus atom and a sulfur atom and having an algyrodite type crystal structure (hereinafter referred to as “sulfide”). , (A) Also referred to as sulfide) and (B) phosphorus sulfide are mixed without using a crusher, a drying step of removing the solvent, and a drying step of removing the solvent. , A method for producing a solid electrolyte.

In the present specification, the solid electrolyte means an electrolyte that maintains a solid at 25 ° C. under a nitrogen atmosphere. The solid electrolyte in the present embodiment is a solid electrolyte containing a lithium element, a sulfur element, a phosphorus element and a halogen element, and having ionic conductivity due to the lithium element.

According to the production method, _{Li 2} S remaining in the solid electrolyte, which is one of the causes of _{H 2 S generation, can be made into Li 3} PS ₄ or the like which is relatively stable to water or the like, so that the ionic conductivity can be increased. while suppressing a decrease Hakare improvement in water resistance is believed that the generation of H 2 _S is suppressed.
Further, since the production method is carried out in the presence of at least one solvent selected from a non-polar solvent and an aproton solvent, preferably in at least one solvent selected from a non-polar solvent and an aproton solvent, it is a solid. Not the reaction of (A) sulfide and solid (B) phosphorus sulfide, but because part or all of (B) phosphorus sulfide is dissolved in an aproton solvent, only on the surface of (A) sulfide. It is considered that (A) the sulfide can easily enter the pores and react without using a crusher.
The compound produced by the reaction of (A) sulfide and (B) phosphorus sulfide is also formed on the surface of (A) sulfide and the wall surface in the pores, thereby suppressing the decrease in ionic conductivity while suppressing the decrease in ionic conductivity. water resistance is improved, generation of H 2 _S is suppressed, is considered to be a solid electrolyte having a cubic Arujirodaito type crystal structure.

Further, in the reaction between solids, since the reaction does not proceed unless the solids come into contact with each other, it is difficult to obtain a homogeneous solid electrolyte, and it is difficult to obtain a homogeneous solid electrolyte even if the reaction time is lengthened. On the other hand, in the present embodiment, since the solid-liquid reaction is carried out, a homogeneous solid electrolyte can be obtained in a short time.
In addition, by performing the production in at least one solvent selected from a non-polar solvent and an aprotic solvent, the non-crystallization of the solid electrolyte can be minimized, so that a heating step is required after that step. Therefore, granulation by heating does not occur, it can be carried out with a simple manufacturing facility, and the amount of energy dropped during manufacturing can be suppressed, which is preferable.

<Solvent>
The solvent of this embodiment is at least one solvent selected from a non-polar solvent and an aprotic solvent. The solvent of the present embodiment preferably dissolves phosphorus (B) sulfide, which is the raw material of the present embodiment, from the viewpoint of uniformly and easily producing a solid electrolyte, and is easy to handle without requiring a mixing step. From the viewpoint of sex, it is preferable to use only one kind, and from the viewpoint that the solubility can be easily adjusted by appropriately selecting two or more kinds of solvents having different solubilities, it is also preferable to use two or more kinds in combination. ..

The non-polar solvent and the aprotic solvent of the present embodiment are solvents ^{that do not have easily donated protons (H +} ), and are preferably non-polar solvents from the viewpoint of suppressing side reactions (B). From the viewpoint of dissolving phosphoric acid sulfide, inorganic salts and the like, an aprotic polar solvent is preferable.
The non-polar solvent of the present invention means a solvent having no polarity or low polarity, and is a solvent composed of a carbon atom and a hydrogen atom, and a solid electrolyte can be produced uniformly and easily because of its availability and solubility. From the viewpoint of the above, saturated hydrocarbons, unsaturated hydrocarbons and aromatic hydrocarbons are preferable.

Saturated hydrocarbons are pentane, hexane, heptane, octane, 2-ethylhexane, decane, cyclohexane, methylcyclohexane, decalin, IP solvent 1016 (manufactured by Idemitsu Kosan Co., Ltd.) or IP solvent 1620 (manufactured by Idemitsu Kosan Co., Ltd.) for the above reasons. ) Is preferable.
The unsaturated hydrocarbon is preferably hexene, cyclohexene or heptene for the above reasons.
For the above reasons, the aromatic hydrocarbon is preferably benzene, toluene, xylene, ethylbenzene, tetrahydronaphthalene, Ipsol 100 (manufactured by Idemitsu Kosan Co., Ltd.) or Ipsol 150 (manufactured by Idemitsu Kosan Co., Ltd.).

Among the non-polar solvents, hexane, heptane, cyclohexane, benzene, toluene or xylene are more preferable, heptane toluene or xylene is more preferable, and toluene is even more preferable from the viewpoint of solute solubility, boiling point, toxicity and availability. preferable.

The aprotonic polar solvent of the embodiment is a solvent having a hetero atom, and from the viewpoint of dissolving (B) phosphoric acid sulfide, an inorganic salt, etc., an ether type, a ketone type, an ester type, a nitrile type, an amide type, and a dioxolane. System and sulfolane solvents are preferred.

This embodiment is carried out in the presence of at least one solvent selected from a non-polar solvent and an aprotic solvent, and the step of mixing (A) sulfide and (B) phosphorus sulfide is carried out in the non-polar solvent and the aprotic solvent. It is preferable to carry out in at least one solvent selected from the above.
To carry out the mixing step in at least one solvent selected from a non-polar solvent and an aprotic solvent means that (B) all phosphorus sulfide is dissolved in the aprotic solvent at the initial stage of the mixing step. It is preferable that the portion is dissolved and all the solid (A) sulfide is in the solvent.

Further, in this embodiment, since the mixing step of (A) sulfide and (B) phosphorus sulfide is performed in the presence of at least one solvent selected from a non-polar solvent and an aprotic solvent, excessive (B) sulfide is performed. It is preferable in that unnecessary compounds such as phosphorus and by-products can be removed and a decrease in ionic conductivity can be suppressed.

The amount of at least one solvent selected from the non-protic solvent and the aprotic solvent of the present embodiment is 1 g of (A) sulfide from the viewpoint of obtaining a solid electrolyte that is homogeneous and has suppressed decrease in ionic conductivity. On the other hand, it is preferably 1 mL (milliliter, hereinafter, mL is used as milliliter) or more, more preferably 5 mL or more, further preferably 8 mL or more, and it is carried out in a simple manufacturing facility. It is preferably 40 mL or less, more preferably 30 mL or less, and even more preferably 25 mL or less.

<(A) Sulfide>
The sulfide (A) used in the present embodiment is, for example, Li ₆ PS ₅ X, Li _7-x PS _6-x X _x (X = Cl, Br, I, x = 0.0 to 1.8). Etc. (Japanese Patent Laid-Open No. 2011-096630, Japanese Patent Application Laid-Open No. 2013-21171, etc.), but from the viewpoint of obtaining higher ionic conductivity, it may be possessed as a main crystal. preferable. In the present specification, "having as a main crystal" means that the ratio of the target crystal structure to the crystal structure is 80% or more, preferably 90% or more, and 95% or more. Is more preferable.
Diffraction peaks of these algyrodite crystal structures appear near, for example, 2θ = 15.3 °, 17.7 °, 31.1 °, 44.9 °, and 47.7 °.

Further, examples of the algyrodite-based crystal structure include the following.
_{The composition formula Li 7-x} P _1-y Si _y S ₆ and Li _{7 + x} P _1-y Si _y S ₆ having the above-mentioned _{structural skeleton of Li 7} PS ₆ and having a part of P replaced with Si (Li 7 + x P 1-y Si y S 6 ( The crystal structure represented by x is −0.6 to 0.6 and y is 0.1 to 0.6) is cubic or oblique, preferably cubic, and X-ray diffraction measurement using CuKα rays. At 2θ = 15.5 °, 18.0 °, 25.0 °, 30.0 °, 31.4 °, 45.3 °, 47.0 °, and 52.0 °. Has a peak.

The crystal structure represented by the above composition formula Li _7-x-2y PS _6-xy Cl _x (0.8 ≤ x ≤ 1.7, 0 <y ≤ -0.25 x + 0.5) is preferably cubic. In the X-ray diffraction measurement using CuKα ray in the crystal, mainly 2θ = 15.5 °, 18.0 °, 25.0 °, 30.0 °, 31.4 °, 45.3 °, 47. It has peaks appearing at 0 ° and 52.0 °.
The crystal structure represented by the above composition formula Li _7-x PS _6-x Ha _x (Ha is Cl or Br, x is preferably 0.2 to 1.8) is preferably cubic and uses CuKα rays. In the X-ray diffraction measurement, mainly 2θ = 15.5 °, 18.0 °, 25.0 °, 30.0 °, 31.4 °, 45.3 °, 47.0 °, and 52.0. It has a peak that appears at the ° position.
The peak positions may be moved back and forth within a range of ± 0.5 °.

The sulfide (A) used in the present embodiment preferably does not contain _{crystalline Li 3} PS ₄ (β-Li ₃ PS _{4) from the viewpoint of obtaining higher ionic conductivity.} Whether or not it does not contain crystalline Li ₃ PS ₄ (β-Li ₃ PS ₄ ) is determined by the presence or absence of diffraction peaks of 2θ = 17.5 ° and 26.1 ° found in _{crystalline Li 3} PS _4. In the present specification, if the diffraction peak is not present, or even if the diffraction peak is present, a peak extremely small compared to the diffraction peak of the algyrodite type crystal structure can be detected. It is assumed that Li ₃ PS ₄ (β-Li ₃ PS ₄ ) is not contained.

The shape of the sulfide (A) used in the present embodiment is not particularly limited, but may be matched to the required shape of the solid electrolyte produced in the present embodiment, and examples thereof include a particulate shape. .. The average particle size (D ₅₀ ) of the particulate solid electrolyte is preferably 0.01 μm or more, preferably 0.03 μm or more, because the particle size of the produced solid electrolyte is the required particle size. It is more preferably 50 μm or less, more preferably 0.05 μm or more, further preferably 0.1 μm or more, and it is possible to suppress a decrease in ionic conductivity. It is preferably 100 μm or less, more preferably 50 μm or less, further preferably 10 μm or less, and even more preferably 3 μm or less.

((A) Method for producing sulfide)
Hereinafter, preferred embodiments of (A) sulfide production will be described.
The sulfide (A) used in the present embodiment is obtained by mixing and pulverizing a starting material of a sulfide such as lithium sulfide, phosphorus sulfide, and lithium halide in a solvent, and heating the obtained raw material mixture. (A) Sulfide is obtained by making a calcined product and firing the calcined product.
Further, the sulfide (A) is obtained by heating the raw material mixture in a solvent and calcining it, and then calcining the obtained calcined product.

As the solvent, an organic solvent can be used, and preferably a non-polar solvent, a polar solvent, or a mixed solvent thereof can be used. It is preferable that a non-polar solvent or a solvent containing a non-polar solvent as a main component, for example, 95% by mass or more of the total organic solvent is a non-polar solvent.

As the non-polar solvent, a hydrocarbon solvent is preferable. As the hydrocarbon-based solvent, saturated hydrocarbons, unsaturated hydrocarbons or aromatic hydrocarbons can be used.
Examples of saturated hydrocarbons include hexane, pentane, 2-ethylhexane, heptane, decane, tridecane, cyclohexane, and decalin.
Examples of unsaturated hydrocarbons include hexene, heptene, cyclohexene and the like.
Examples of aromatic hydrocarbons include toluene, xylene, ethylbenzene, 1,2,3,4-tetrahydronaphthalene and the like.
Of these, toluene or xylene is preferred.

The hydrocarbon solvent is preferably dehydrated in advance. Specifically, the water content is preferably 100 mass ppm or less, and particularly preferably 30 mass ppm or less.

In one embodiment, the organic solvent preferably contains at least one of a nitrile compound and an ether compound.
Examples of the ether compound include tetrahydrofuran, diethyl ether and the like.
As the nitrile compound, a nitrile compound represented by _{R (CN) n is preferable.} In the formula, R is an alkyl group having 1 or more and 10 or less carbon atoms, or a group having an aromatic ring having 6 or more and 18 or less ring-forming carbon atoms. n is 1 or 2.

Examples include acetonitrile, propionitrile, 3-chloropropionitrile, benzonitrile, 4-fluorobenzonitrile, tertiary butyronitrile, isobutyronitrile, cyclohexylnitrile, capronitrile, isocapronitrile, malononitrile, fumalnitrile. Be done. Propionitrile, isocapronitrile, and isobutyronitrile are preferable.
For example, since the nitrile compound azeotropes with toluene, it is preferable because it can be easily removed from the treated product together with toluene during drying.
The amount of the nitrile compound and the ether compound contained in the organic solvent is preferably 0.01 to 5% by mass, more preferably 0.1 to 3% by mass, and particularly 0.3 to 1% by mass. Is preferable.

For mixing and crushing, for example, a crusher such as a planetary ball mill, a vibration mill, a rolling mill, a bead mill, or a ball mill, or a kneader such as a uniaxial kneader or a multi-screw kneader can be used.

The raw material mixture obtained by removing the solvent from the processed product after mixing and pulverizing is mainly formed of fine crystals. By mixing and pulverizing the raw materials, the atomization of the raw materials progresses, and a raw material mixture composed of fine crystals of each raw material is obtained.

A calcined product is obtained by calcining the raw material mixture. In one embodiment, the solvent is removed as described above to obtain a raw material mixture, which is then calcined to obtain a powdery calcined product. The heating temperature and time in the calcining can be appropriately adjusted in consideration of the composition of the calcined product and the like. For example, the heating temperature is preferably 150 ° C. to 300 ° C., more preferably 160 ° C. to 280 ° C., and particularly preferably 170 ° C. to 250 ° C. The heating time is preferably 0.1 to 8 hours, more preferably 0.2 to 6 hours, and particularly preferably 0.25 to 4 hours.

The heating device used for calcining is not particularly limited. For example, a shearing dryer such as an FM mixer or a nauta mixer, a stationary furnace such as a herskillon, or a rotary furnace such as a rotary kiln can be mentioned. It should be noted that drying may be performed before calcining, and drying and calcining may be performed at the same time. The atmosphere of the calcining is not particularly limited, but an atmosphere of an inert gas such as nitrogen or argon is preferable.

By firing the calcined product, (A) sulfide is obtained. The heating temperature and time in firing can be appropriately adjusted in consideration of the composition of the calcined product and the like. For example, in the case of an algyrodite type solid electrolyte, the heating temperature is preferably 300 ° C. to 470 ° C., more preferably more than 300 ° C. and 460 ° C. or lower, more preferably 320 ° C. to 450 ° C., and further preferably 350 ° C. to 440 ° C. In particular, 380 ° C. to 430 ° C. is preferable.
The heating time is preferably 1 to 360 minutes, more preferably 5 to 120 minutes, and particularly preferably 10 to 60 minutes.
The atmosphere during heating is not particularly limited, but is preferably under an atmosphere of an inert gas such as nitrogen or argon, not under a hydrogen sulfide stream. For the firing step, a firing furnace such as a stationary harskiln or a rotary rotary kiln can be used.

When the raw material mixture is calcined in a solvent, the above-mentioned non-polar solvent, polar solvent or a mixed solvent thereof can be used as the solvent used for calcining. The slurry in which the raw material mixture is dispersed in the solvent is heated. As the solvent used for calcining, the same solvent as that used for mixing the raw materials or the like may be used, or a different solvent may be used. When the same one is used, it is preferable because the step of removing the solvent is unnecessary.

The heating temperature and time in the calcining can be appropriately adjusted in consideration of the composition of the raw materials and the like. For example, the heating temperature is preferably 150 ° C. to 300 ° C., more preferably 160 ° C. to 280 ° C., further preferably 170 ° C. to 270 ° C., and particularly preferably 180 ° C. to 260 ° C. By the above temperature range, the PS ₄ structure formed, halogens are easily incorporated into the crystal. Also in the first embodiment similarly to the embodiment, since the calcined raw material mixture of fine crystals in the solution, it is possible to form the crystals containing PS ₄ structure at a relatively low temperature.
The heating time is preferably 10 minutes to 6 hours, more preferably 10 minutes to 3 hours, and particularly preferably 30 minutes to 2 hours.
The heating device used for calcining is not particularly limited, but when the heating temperature exceeds the boiling point of the solvent used, it is preferable to use an autoclave.

The solvent is removed from the slurry used for calcining, and the calcined product is recovered. The method for removing the solvent is not particularly limited, but the solvent can be distilled off under normal pressure or reduced pressure. It is also possible to use filtration together in order to increase productivity.
By firing the calcined product, (A) sulfide is obtained.

<(B) Phosphorus sulfide>
The (B) phosphorus sulfide of the present embodiment is (A) lithium sulfide (Li ₂ S) used as a raw material for sulfide; diphosphorus trisulfide (P ₂ S ₃ ), diphosphorus pentasulfide (P ₂ S ₅ ). may be the same sulfide such as phosphorus etc., for solid electrolyte decrease in ionic conductivity is suppressed may be obtained, it is preferable that the phosphorus pentasulfide (P 2 _{S 5).}

In this embodiment, since it is carried out in the presence of at least one solvent selected from a non-polar solvent and an aprotic solvent, the shape of (B) phosphorus sulfide is not particularly limited, but it can be carried out in a simple manufacturing facility, so that it is average. The particle size (D ₅₀ ) is preferably 10 cm or less, more preferably 8 cm or less, and even more preferably 5 cm or less.
Since this embodiment is carried out in the presence of at least one solvent selected from a non-polar solvent and an aprotic solvent, it is preferable to carry out (B) phosphorus sulfide without pulverization from the viewpoint of a simple manufacturing process.

(Amount of (A) sulfide and (B) phosphorus sulfide used)
The amount of (A) sulfide used in this embodiment may be appropriately determined depending on the manufacturing equipment used.
The amount of the (B) phosphorus sulfide of the present embodiment, it is preferable to determine the amount of S ^2-, reduction in ion conductivity in homogeneous contained in an amount and (A) a sulfide of (A) a sulfide Since a suppressed solid electrolyte can be obtained, it is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, based on 100.0 parts by mass of (A) sulfide. It is more preferably 0.0 parts by mass or more, preferably 30.0 parts by mass or less from the viewpoint of reducing the residual amount of unreacted phosphorus (B) sulfide, and more preferably 20.0 parts by mass or less. It is preferably 15.0 parts by mass or less, and more preferably 15.0 parts by mass or less.

<Mixing process>
The method of mixing (A) sulfide and (B) phosphorus sulfide in the presence of at least one solvent selected from the non-polar solvent and the aprotonic solvent of the present embodiment is not particularly limited, and the non-polar solvent and non-polar solvent and non-polar solvent are not particularly limited. In an apparatus capable of mixing (A) sulfide and (B) phosphorus sulfide in the presence of at least one solvent selected from the protonic solvent, (A) sulfide and (B) phosphorus sulfide are mixed in the presence of an aprotonic solvent. It may be added and mixed.

In the present embodiment, if a pulverizer exemplified as one that can be used for the treatment in the method for producing (A) sulfide is used, a step such as crystallization is required thereafter, so that it is necessary not to use the pulverizer. "Without using a crusher" literally means not using a "crusher". The "crusher" is a crusher exemplified as one that can be used for the treatment in the method for producing (A) sulfide. be.

In the present embodiment, examples of the device capable of mixing include a mechanical stirring type mixer having a stirring blade in the tank.
Although "crushing" itself can occur in the following mixers, there is no problem even if a mixer is used because the processing of "crushing" is not the main and the processing of "mixing" is the main.
Examples of the mechanical stirring type mixer include a high-speed stirring type mixer and a double-arm type mixer, which enhance the uniformity of the raw material in the mixture of the raw material-containing material and the complexing agent, and have a predetermined average particle size and specific surface area. At the same time, a high-speed stirring type mixer is preferably used from the viewpoint of obtaining higher ionic conductivity. Further, examples of the high-speed stirring type mixer include a vertical axis rotary type mixer and a horizontal axis rotary type mixer, and either type of mixer may be used.

The shape of the stirring blade used in the mechanical stirring type mixer includes blade type, arm type, ribbon type, multi-stage blade type, double arm type, excavator type, biaxial blade type, flat blade type, C type blade type, etc. From the viewpoint of increasing the uniformity of the raw material in the raw material content and obtaining higher ionic conductivity as well as a predetermined average particle size and specific surface area, a shovel type, a flat blade type, a C type blade type and the like are preferable. ..

Since this embodiment is carried out in the presence of at least one solvent selected from a non-polar solvent and an aprotic solvent, it is preferable not to use a medium-type crusher such as a ball mill as in Patent Document 2. As a result, (A) sulfide decrystallization can be suppressed, and the subsequent heating step to 200 ° C. or higher for the purpose of forming an algyrodite type crystal type is not required, resulting in granulation. It can be suppressed.

The step of mixing in the present embodiment is not particularly limited and may be performed without adjusting the temperature such as heating or cooling from the outside, but the step time is shortened and the decrease in ionic conductivity is suppressed. From the viewpoint of obtaining the above, heating may be performed, preferably at a temperature lower than 100 ° C., more preferably at a temperature lower than 90 ° C. Therefore, it is preferably performed at −20 ° C. or higher, more preferably at 0 ° C. or higher, and further preferably without heating.

In addition, also in the method described in Patent Document 1, the mixed powder obtained by pulverizing and mixing with a ball mill crusher is heated at 200 ° C. for 2 hours, but this is because the crystal structure collapsed by pulverization and mixing is reconstituted into an algyrodite structure. This is different from heating for shortening the time of the mixing step as in the present embodiment. Therefore, in Cited Document 1, the temperature is as high as 200 ° C., which is sufficient for crystal transition to the algyrodide structure, which is significantly different from the temperature of less than 100 ° C. in the present embodiment.

The time for performing the mixing step of the present embodiment may be determined based on (B) the consumption of phosphorus sulfide, and is not particularly limited, but for example, 1 hour or more is preferable, 3 hours or more is more preferable, and 5 hours or more. The above is more preferable.
From the viewpoint of production efficiency, 24 hours or less is preferable, 18 hours or less is more preferable, 12 hours or less is further preferable, and 10 hours or less is further preferable.
From the viewpoint of suppressing the decrease in ionic conductivity, 120 hours or less is preferable, 100 hours or less is more preferable, and 80 hours or less is further preferable.

The mixing step of the present embodiment is preferably carried out at a high dew point (for example, a dew point of −60 to −20 ° C.) at the level of a dry room in an atmosphere of an inert gas.
It may be carried out at atmospheric pressure, but when a compound having a low boiling point such as an aprotic solvent is used, it is also preferable to carry out the work while pressurizing in an autoclave or the like.

<Drying process>
In the present embodiment, a further drying step is required after the step of mixing (A) sulfide and (B) phosphorus sulfide.
By performing the drying step of removing at least one solvent selected from the non-polar solvent and the aprotic solvent used in the present embodiment, impurities are reduced and ionic conductivity can be expected to be improved. On the other hand, when the solid electrolyte tends to form aggregates due to drying, it is preferable to appropriately adjust the drying temperature and drying time described later.

The drying may be carried out without heating or from the viewpoint of reducing the drying time, preferably at 50 ° C. or higher, preferably at 70 ° C. or higher, and preferably at 90 ° C. or higher. From the viewpoint of granulation and suppression of deterioration of ionic conductivity, the temperature is preferably 150 ° C. or lower, more preferably 150 ° C. or lower, and even more preferably 120 ° C. or lower.
The drying time may be determined by the residual amount of the aprotic solvent and is not particularly limited. For example, 1 minute or more is preferable, 10 minutes or more is more preferable, 30 minutes or more is further preferable, and 1 hour or more is further more preferable. preferable. The upper limit of the drying time is not particularly limited, but is preferably 24 hours or less, more preferably 12 hours or less, further preferably 6 hours or less, still more preferably 3 hours or less.

Further, the drying may be carried out by filtering the precursor or mixture with a solvent using a glass filter or the like, solid-liquid separation by decantation, or solid-liquid separation using a centrifuge or the like. In the present embodiment, after solid-liquid separation, drying under the above temperature conditions may be performed.
In the solid-liquid separation, specifically, a decantation in which the precursor and the mixture accompanied by the solvent are transferred to a container and the solvent that becomes the supernatant is removed after the precursor and the mixture are precipitated, and for example, the pore size is about 10 to 200 μm. Filtration using a glass filter of preferably 20 to 150 μm is easy.
It is preferable not to heat the solid electrolyte after the drying step from the viewpoint of suppressing granulation of the solid electrolyte.

<Solid electrolyte>
The solid electrolyte of this embodiment, (A) a sulfide hand, decreases the content of such Li 2 _S, the content of the compound reacted with the component (A) of the sulfide (B) phosphorus sulfide, used (B) The composition increased depending on the amount of phosphorus sulfide.
Further, the crystal structure of the solid electrolyte of the present embodiment has the above-mentioned algyrodite type crystal structure, but it is preferably provided as the main crystal from the viewpoint of obtaining higher ionic conductivity. In the present specification, "having as a main crystal" means that the ratio of the target crystal structure to the crystal structure is 80% or more, preferably 90% or more, and 95% or more. Is more preferable.

The surface layer portion of the solid electrolyte in which A) the sulfide component is present in a larger amount of the compound that has reacted with (B) phosphorus sulfide may be an amorphous solid electrolyte. The presence of this amorphous solid electrolyte is preferable because the solid electrolytes are easily heat-sealed by pressure-bonding or the like when manufacturing an all-solid-state battery.

Next, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these examples.
1. 1. Measurement method 1-1. (A) Crystal structure of sulfide and solid electrolyte The powder of the sample was ground into a groove having a diameter of 20 mm and a depth of 0.2 mm with glass to prepare a sample. This sample was measured with a Kapton film for XRD without contact with air.
It was carried out under the following conditions using the powder X-ray diffraction measuring device D2 PHASER of Bruker Co., Ltd.

Tube voltage: 30 kV
Tube current: 10 mA
X-ray wavelength: Cu-Kα ray (1.5418 Å)
Optical system: Concentration method Slit configuration: Solar slit 4 °, divergence slit 1 mm, Kβ filter (Ni plate) used

Detector: Semiconductor detector Measuring range: 2θ = 10-60deg
Step width, scan speed: 0.05 deg, 0.05 deg / sec
1-2. (A) Chemical composition of sulfide and solid electrolyte Composition analysis was performed by ICP analysis (inductively coupled plasma emission spectroscopic analysis).

1-3. Ion Conductivity of Solid Electrolyte A circular pellet having a diameter of 10 mm (cross-sectional area S: 0.785 cm ² ) and a height (L) of 0.1 to 0.3 cm was formed from the solid electrolyte and used as a sample. Electrode terminals were taken from above and below the sample and measured by the AC impedance method at 25 ° C. (frequency range: 5 MHz to 0.5 Hz, amplitude: 10 mV) to obtain a Core-Cole plot. The real part Z'(Ω) at the point where −Z'' (Ω) is minimized near the right end of the arc observed in the high frequency side region is defined as the bulk resistance R (Ω) of the electrolyte, and the ions are according to the following equation. The conductivity σ (S / cm) was calculated.

1-4. Exposure test of the solid electrolyte _{(H 2} S generation amount)
First, the test device (exposure test device 1) used in the exposure test will be described with reference to FIG.
The exposure test device 1 includes a flask 10 for humidifying nitrogen, a static mixer 20 for mixing humidified nitrogen and non-humidified nitrogen, and a dew point meter 30 (M170 / DMT152 manufactured by VAISALA) for measuring the water content of the mixed nitrogen. , A double reaction tube 40 in which a measurement sample is installed, a dew point meter 50 for measuring the water content of nitrogen discharged from the double reaction tube 40, and a hydrogen sulfide measurement for measuring the concentration of hydrogen sulfide contained in the discharged nitrogen. A vessel 60 (Model 3000RS manufactured by AMI) is used as a main component, and these are connected by a pipe (not shown). The temperature of the flask 10 is set to 10 ° C. by the cooling tank 11.
A Teflon (registered trademark) tube with a diameter of 6 mm was used for the tube connecting each component. In this figure, the notation of the pipe is omitted, and the flow of nitrogen is indicated by an arrow instead.

The evaluation procedure was as follows.
About 1.5 g of the powder sample (solid electrolyte) 41 was weighed in a nitrogen glow box having a dew point of −80 ° C., and placed inside the reaction tube 40 so as to be sandwiched between quartz wool 42 and sealed. The evaluation was performed at room temperature (20 ° C.).
Nitrogen was supplied into the apparatus 1 from a nitrogen source (not shown) at 0.02 MPa. The supplied nitrogen passes through the bifurcated branch pipe BP, and a part of the supplied nitrogen is supplied to the flask 10 to be humidified. Others are directly supplied to the static mixer 20 as non-humidifying nitrogen. The amount of nitrogen supplied to the flask 10 is adjusted by the needle valve V.

The dew point is controlled by adjusting the flow rates of unhumidified nitrogen and humidified nitrogen with a flow meter FM with a needle valve. Specifically, the flow rate of unhumidified nitrogen is 800 mL / min, and the flow rate of humidified nitrogen is 10 to 30 mL / min. And the dew point of the humidified nitrogen mixture) was confirmed.

After adjusting the dew point to −30 ° C., the three-way cock 43 was rotated to allow the mixed gas to flow inside the reaction tube 40 for the time shown in Table 1. The amount of hydrogen sulfide contained in the mixed gas that passed through the sample 41 was measured with a hydrogen sulfide measuring instrument 60. The amount of hydrogen sulfide was recorded at intervals of 15 seconds and measured as the amount generated per minute (mL / min). For reference, the dew point of the mixed gas after exposure was measured with a dew point meter 50.
In order to remove hydrogen sulfide from the nitrogen after the measurement, the alkali trap 70 was passed through.

1-5. Average particle size The average particle size (D50) is the particle size at which the particles with the smallest particle size are sequentially integrated to reach 50% of the total when the particle size distribution integration curve is drawn. For example, as follows. Be measured. The measurement was performed with a laser diffraction / scattering type particle size distribution measuring device (manufactured by HORIBA, LA-950V2 model LA-950W2).
A mixture of dehydrated toluene (manufactured by Wako Pure Chemical Industries, Ltd., special grade) and tert-butyl alcohol (manufactured by Wako Pure Chemical Industries, Ltd., special grade) at a mass ratio of 93.8: 6.2 was used as a dispersion medium. After injecting 50 mL of the dispersion medium into the flow cell of the apparatus and circulating it, the object to be measured was added and ultrasonically treated, and then the particle size distribution was measured. The amount of addition to be measured is 80 to 90% for the red light transmittance (R) and 70 to 90% for the blue light transmittance (B) corresponding to the particle concentration on the measurement screen specified by the device. Adjusted to fit. Further, as the calculation conditions, 2.16 was used as the value of the refractive index of the measurement target, and 1.49 was used as the value of the refractive index of the dispersion medium. In setting the distribution form, the particle size was calculated by fixing the number of repetitions to 15.

1-6. It was measured by the nitrogen method using a BET specific surface area gas adsorption amount measuring device (AUTOSORB6 (manufactured by Sysmex Corporation)).
1-7. Residual solvent amount Measured with a gas chromatograph (Type 6890 manufactured by Agilent).

2-1. Synthesis of lithium sulfide In a 500 mL separable flask (equipped with an anchor stirring blade), lithium hydroxide anhydride (manufactured by Honjo Chemical Co., Ltd., particle size range: 0.1 mm or more and 1.5 mm or less, moisture content) under a nitrogen stream. Amount: 1% by mass or less) 200 g was added, and the temperature was raised to 200 ° C. using an oil bath while stirring at 60 rpm and maintained. The upper part of the separable flask was held at 100 ° C. with a ribbon heater. Nitrogen was switched to hydrogen sulfide (manufactured by Tomoe Shokai Co., Ltd.), and the reaction between lithium hydroxide and hydrogen sulfide was carried out while supplying at a flow rate of 500 mL / min. The water generated by the progress of the reaction was condensed and recovered by a condenser, and when the reaction was carried out for 6 hours, 144 mL of water was recovered and continued for another 3 hours, but no water was generated.

Then, while maintaining the temperature at 200 ° C., hydrogen sulfide was switched to nitrogen, nitrogen was aerated for 20 minutes, and hydrogen sulfide in the flask was replaced with nitrogen.
When obtained lithium sulfide (Li 2 _S) powder was determined by potentiometric titration, the content of lithium sulfide (purity) is 99.1 wt%, a specific surface area became 7 m 2 ^{/ g.}

2-2. The Li ₂ S obtained in Preparation (A) pulverizing step 2-1 above sulfide (A-1), under a nitrogen atmosphere and then pulverized by a pin mill having a metering feeder (manufactured by Hosokawa Micron Corporation 100UPZ). The loading speed was 80 g / min, and the rotation speed of the disk was 18000 rpm.
_Similarly, P 2 _{S 5} (manufactured by Samofosu), LiBr (manufactured by Honjo Chemical Corporation) and LiCl (manufactured by Honjo Chemical Corporation), respectively, were pulverized in a pin mill. P ₂ S input rate is 140 g / min of _5, input rate of LiBr is 230 g / min, input rate of LiCl was 250 g / min. The rotation speed of the disks was 18000 rpm.

(B) Preparation of raw material mixture In a glove box with a nitrogen atmosphere, each compound crushed in (A) above has a molar ratio of Li ₂ S: P ₂ S ₅ : LiBr: LiCl = 47.5: 12.5. 15.0: 25.0, which was weighed to a total of 110 g, was put into a glass container and roughly mixed by shaking the container.
110 g of the crudely mixed raw material was dispersed in a mixed solvent of 1140 mL of dehydrated toluene (manufactured by Wako Pure Chemical Industries, Ltd.) and 7 mL of dehydrated isobutyronitrile (manufactured by Kishida Chemical Industries, Ltd.) under a nitrogen atmosphere, and about 10% by mass was dispersed. It was made into a slurry. While maintaining the nitrogen atmosphere, the slurry was mixed and pulverized using a bead mill (LMZ015, manufactured by Ashizawa Finetech). Specifically, 456 g of zirconia beads having a diameter of 0.5 mm were used as the pulverization medium, the bead mill was operated under the conditions of a peripheral speed of 12 m / s and a flow rate of 500 mL / min, and the slurry was charged into the mill. It was circulated for 1 hour. The treated slurry was placed in a nitrogen-substituted Schlenk bottle and then dried under reduced pressure to prepare a raw material mixture.

(C) Temporary baking step 30 g of the raw material mixture obtained in the above (B) was dispersed in 300 mL of ethylbenzene (manufactured by Wako Pure Chemical Industries, Ltd.) to prepare a slurry. This slurry was put into an autoclave (capacity: 1000 mL, manufactured by SUS316) equipped with a stirrer and an oil bath for heating, and heat-treated at 200 ° C. for 2 hours while stirring at a rotation speed of 200 rpm. After the treatment, it was dried under reduced pressure and the solvent was distilled off to obtain a calcined product.

(D) Baking Step The calcined product obtained in (C) above was heated in an electric furnace (F-1404-A, manufactured by Tokyo Glass Instruments Co., Ltd.) in a glove box under a nitrogen atmosphere. Specifically, put an Al ₂ O ₃ saggar (999-60S, manufactured by Tokyo Glass Instruments Co., Ltd.) in an electric furnace, raise the temperature from room temperature to 380 ° C in 1 hour, and hold it at 380 ° C for 1 hour or more. bottom. Then, the door of the electric furnace was opened, the calcined product was quickly poured into the sack, the door was closed immediately, and the mixture was heated for 1 hour. Then, the saggar was taken out from the electric furnace and slowly cooled to obtain an algyrodite type solid electrolyte ((A) sulfide).

(E) Finening Step The obtained algyrodite-type solid electrolyte is dispersed in a mixed solvent of dehydrated toluene (manufactured by Wako Pure Chemical Industries, Ltd.) and dehydrated isobutyronitrile (manufactured by Kishida Chemical Industries) under a nitrogen atmosphere, and is about 8 It was made into a mass% slurry. While maintaining the nitrogen atmosphere, the slurry was mixed and pulverized using a bead mill (LMZ015, manufactured by Ashizawa Finetech). The treated slurry was placed in a nitrogen-substituted Schlenk bottle and then dried under reduced pressure to obtain a micronized algyrodite-type solid electrolyte (sulfide (A-1)).

As a result of X-ray diffraction (XRD) measurement, peaks derived from the algyrodite type crystal structure were observed in the XRD pattern at 2θ = 25.5 ± 1.0 deg and 29.9 ± 1.0 deg.
d50 was 1.7 μm. The ionic conductivity was 4.9 mS / cm.

2-3. Preparation of Sulfide (A-2) In the (E) micronization step, a micronized algyrodite-type solid electrolyte (sulfide (A-2)) was obtained in the same manner as in Production Example 1 except that the pulverization conditions were changed. ..
As a result of X-ray diffraction (XRD) measurement, peaks derived from the algyrodite type crystal structure were observed in the XRD pattern at 2θ = 25.5 ± 1.0 deg and 29.9 ± 1.0 deg.
d50 was 0.6 μm. The ionic conductivity was 4.6 mS / cm.

(Examples 1 to 3)
Under a nitrogen atmosphere, Arujirodaito solid electrolyte obtained in 2-2 (sulfide (A-1)) and _were weighed and P 2 _{S 5} (manufactured by Samofosu) in a Schlenk bottle 50 mL of under the conditions of Table 1 .. While maintaining the nitrogen atmosphere, 20 mL of toluene (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., water content of 10 ppm or less) was added to obtain a mixture. In Table 1, the _{amount of P 2} S ₅ added is the amount added when sulfide A-1 or sulfide A-2 is 100 parts by mass.

Further, while maintaining the nitrogen atmosphere, the stirrer tip was added and stirred at room temperature (25 ° C.) for 72 hours. Then, it was vacuum dried at room temperature for 1 hour to remove the solvent to obtain a dry powder. The obtained dry powder was vacuum dried at 80 ° C. for 1 hour to obtain solid electrolytes -1 to 3.
Table 1 shows the evaluation results of the ionic conductivity, the amount of hydrogen sulfide generated, the average particle size d50, and the amount of hydrogen sulfide generated of the obtained solid electrolyte. In addition, it was confirmed from the results of the powder X-ray diffraction measuring device that all the solid electrolytes had an algyrodite structure.
The amount of toluene remaining in the solid electrolyte was less than 0.1% by weight.

(Comparative Example 1)
As Comparative Example 1, the results of sulfide (A-1) are shown in Table 1.

(Examples 4 and 5)
A sulfide (A-2) was used instead of the sulfide (A-1) of Example 1, and the amount of diphosphorus pentasulfide used and the mixing time were set as shown in Table 1 in the same manner as the solid electrolyte-. 4 and 5 were obtained. The results are shown in Table 1.
The ICP analysis and particle size measurement results of the obtained solid electrolytes -4 and 5 did not show a significant difference from the sulfide (A-2).
In addition, it was confirmed from the results of the powder X-ray diffraction measuring device that all the solid electrolytes had an algyrodite structure.
(Comparative Example 2)
As Comparative Example 2, the results of sulfide (A-2) are shown in Table 1.

(Examples 6 and 7)
Under a nitrogen atmosphere, the sulfide and _(A-2), were weighed and P 2 _{S 5} (manufactured by Samofosu) to high pressure decomposition reaction vessel 50 mL of under the conditions of Table 1. While maintaining the nitrogen atmosphere, 20 mL of toluene (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., water content of 10 ppm or less) was added to obtain a mixture. Further, while maintaining the nitrogen atmosphere, the stirrer tip was put in and sealed, and the mixture was stirred at 80 ° C. for 8 hours. Then, it was vacuum dried at room temperature for 1 hour to remove the solvent to obtain a dry powder. The obtained dried powder was vacuum dried at 80 ° C. for 1 hour to obtain solid electrolytes -6 and 7.
Table 1 shows the evaluation results of the ionic conductivity, the amount of hydrogen sulfide generated, the average particle size d50, and the amount of hydrogen sulfide generated of the obtained solid electrolyte.

The amount of toluene remaining in the solid electrolyte was less than 0.1% by weight.
The ICP analysis and particle size measurement results of the obtained solid electrolytes -6 and 7 did not show a significant difference from the sulfide (A-2).
In addition, it was confirmed from the results of the powder X-ray diffraction measuring device that all the solid electrolytes had an algyrodite structure.

(Comparative Example 3)
And 0.9445 g of the sulfide _{(A-1), P 2} S 5 (manufactured by Samofosu) and 0.0505 g, and zirconia balls 26.5 g having a diameter of 2 mm, the zirconia pot (45 mL) and It was put in and completely sealed, and the inside of the pot was made into an argon atmosphere. Without heating and cooling, a planetary ball mill (manufactured by Fritsch Co., Ltd .: model number P-7) was used as a "crusher" at a rotation speed of 100 rpm and treated for 2 hours (mechanical milling) to obtain a powder.

The obtained powder was filled in a glass container and heated at 200 ° C. for 2 hours to obtain a solid electrolyte-C1.
Table 1 shows the evaluation results of the ionic conductivity, hydrogen sulfide generation amount, average particle size d50 and hydrogen sulfide generation amount of the obtained solid electrolyte-C1. Further, it was confirmed from the result of the powder X-ray diffraction measuring device that the solid electrolyte-C1 has an algyrodite structure.

The amount of P ₂ S ₅ added (parts by mass) in Table 1 represents the amount of (B) phosphorus sulfide added (parts by mass) with respect to (A) 100.0 parts by mass of sulfide.
Note 1) in Table 1 means that "the obtained powder was filled in a glass vial container and heated in a tubular electric furnace at 200 ° C. for 2 hours" described in Comparative Example 3.

A homogeneous solid electrolyte was easily obtained by the production method of the present invention. Further, a solid electrolyte obtained by the production method of the present invention, generation of H _{2 S} compared to mixing is not performed steps sulfide of the (corresponding to Comparative Examples 1 and 2) can be greatly reduced, It was found that the suppression of the decrease in ionic conductivity can also be improved.
In Comparative Example 3, a solid electrolyte-C1 was obtained by a production method using a crusher (planetary ball mill) corresponding to the production method of Patent Document 2 described above. But the solid electrolyte -C1, although suppressed to the same extent as the solid electrolyte produced by what the production method H 2 _S emissions, ionic conductivity is significantly reduced, also the particle size by granulation has become larger. From this, it was confirmed that it is necessary to carry out the mixing step without using a "crusher". Further, when a "crusher" is used in the "mixing process", it is necessary to reduce the particle size in order to use it for the solid electrolyte layer for an all-solid-state battery, so that a separate crushing process is required. It turned out that it would end up.

On the other hand, since the surface of the solid electrolyte produced by this production method did not become amorphous, the step of crystallization by heating was unnecessary as the next step. As a result, granulation by heating does not occur, so that no further pulverization step is required.

According to the manufacturing method of the solid electrolyte of the present embodiment, improved water resistance and suppressing the generation of H _{2 S,} homogeneously and conveniently a solid electrolyte having a cubic Arujirodaito type crystal structure to suppress the decrease in ionic conductivity Can be manufactured in.
The crystalline solid electrolyte obtained by the production method of the present embodiment is suitably used for a battery, particularly a battery used for an information-related device such as a personal computer, a video camera, a mobile phone, a communication device, or the like.

1. 1. Test equipment used in exposure test (exposure test equipment)
10. Flask for humidifying nitrogen 11. Cooling tank 20. Static mixer 30. Dew point meter 40. Double reaction tube on which the measurement sample is placed 41. Powder sample 42. Quartz wool 43. Three-way cock 50. Dew point meter 60. Measures the water content of nitrogen discharged from the double reaction tube 40. Hydrogen sulfide measuring instrument 70. Alkaline trap V. Needle valve

Claims (13)

In the presence of at least one solvent selected from non-polar and aprotic solvents
A step of mixing (A) a sulfide containing a lithium atom, a phosphorus atom and a sulfur atom and having an algyrodite type crystal structure, and (B) phosphorus sulfide without using a crusher.
A drying step of removing the solvent and
A method for producing a solid electrolyte. The method for producing a solid electrolyte according to claim 1, wherein the mixing step is carried out in at least one solvent selected from a non-polar solvent and an aprotic solvent. The method for producing a solid electrolyte according to claim 1 or 2, wherein the phosphorus sulfide (B) is diphosphorus pentasulfide. The method for producing a solid electrolyte according to any one of claims 1 to 3, wherein heating is performed in the mixing step. The method for producing a solid electrolyte according to claim 4, wherein the heating in the mixing step is performed at a temperature of less than 100 ° C. Any one of claims 1 to 5, wherein the amount of phosphorus sulfide added to 100.0 parts by mass of (A) sulfide in the mixing step is 0.5 parts by mass or more and 30.0 parts by mass or less. The method for producing a solid electrolyte according to. Any of claims 1 to 6, wherein at least one solvent selected from the non-polar solvent and the aprotonic solvent is one or more selected from the group consisting of saturated hydrocarbons, unsaturated hydrocarbons and aromatic hydrocarbons. The method for producing a solid electrolyte according to item 1. The method for producing a solid electrolyte according to any one of claims 1 to 7, wherein at least one solvent selected from the non-polar solvent and the aprotic solvent is toluene, xylene or heptane. The method for producing a solid electrolyte according to any one of claims 1 to 8, wherein the sulfide (A) further contains a halogen atom. The method for producing a solid electrolyte according to claim 9, wherein the halogen atom is one or more selected from the group consisting of a chlorine atom or a bromine atom. The method for producing a solid electrolyte according to any one of claims 1 to 10, wherein (A) sulfide and (B) phosphorus sulfide are used without being crushed. The method for producing a solid electrolyte according to any one of claims 1 to 11, wherein heating to 200 ° C. or higher is not performed after the drying step. The method for producing a solid electrolyte according to any one of claims 1 to 12, which does not use a medium-type crusher.

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