JP2019031437A - Method of manufacturing metal hydrosulfide - Google Patents

Abstract

To provide a method of manufacturing a metal hydrosulfide.SOLUTION: A method of manufacturing a metal hydrosulfide includes generating a metal hydrosulfide by bringing one or more metal sulfides selected from the group consisting of alkali metal sulfides and alkali earth metal sulfides into contact with a sulfide bond-containing compound in an organic solvent.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a modified metal sulfide, a sulfide-based solid electrolyte glass using the same, and a method for producing a sulfide-based solid electrolyte glass ceramic.

Examples of the electrolyte of the lithium ion battery include a sulfide-based solid electrolyte. Lithium sulfide is used as a raw material for sulfide-based solid electrolytes. For the purpose of facilitating the production of sulfide-based solid electrolytes, lithium sulfide that is more reactive has been desired.
Patent Document 1 discloses an invention in which the reactivity of lithium sulfide is improved mainly by modification with an alcohol solvent. However, in general, a process using a solvent requires more equipment than a gas. Therefore, even when an alcohol solvent is used, there is a problem that many facilities are required.

JP 2011-136899 A

  An object of the present invention is to provide a novel modified metal sulfide production method capable of increasing the specific surface area of metal sulfide, and sulfide-based solid electrolyte glass and sulfide-based solid electrolyte glass ceramics using the same. It is to provide a manufacturing method.

According to the present invention, the following modified metal sulfide production method and the like are provided.
1. A first hydrosulfide is produced by contacting one or more metal sulfides selected from the group consisting of alkali metal sulfides and alkaline earth metal sulfides with a sulfide bond-containing compound in an organic solvent. And a second step of converting the metal hydrosulfide into a metal sulfide by a desulfurization hydrogenation reaction.
A method for producing a modified metal sulfide having an increased specific surface area.
2. A first product obtained by contacting one or more metal sulfides selected from the group consisting of alkali metal sulfides and alkaline earth metal sulfides with a sulfide bond-containing compound in an organic solvent at a first temperature is obtained. And a second step of heating the reactant at a second temperature higher than the first temperature.
A method for producing a modified metal sulfide having an increased specific surface area.
3. 3. The method for producing a modified metal sulfide according to 2, wherein the first temperature is −20 ° C. to 150 ° C. and the second temperature is 20 ° C. to 250 ° C.
4). The method for producing a modified metal sulfide according to 2 or 3, wherein the first step is performed twice or more at different first temperatures, and the temperature is increased every time the first step is repeated.
5. 5. The method for producing a modified metal sulfide according to 4, wherein the first step is performed twice at different first temperatures.
6). 6. The method for producing a modified metal sulfide according to 5, wherein the different first temperature is 20 ° C. to 60 ° C. and higher than 60 ° C. and equal to or lower than 100 ° C.
7). 6. The method for producing a modified metal sulfide according to 5, wherein the different first temperature is 40 ° C. to 60 ° C. and higher than 60 ° C. and 80 ° C. or lower.
8). The method for producing a modified metal sulfide according to any one of 2 to 7, wherein the pressure in the first step is from normal pressure to 0.85 MPa.
9. Furthermore, it has the manufacturing process of the said metal sulfide,
The method for producing a modified metal sulfide according to any one of 2 to 8, wherein the first step and the second step are carried out following the production step.
10. The method for producing a modified metal sulfide according to any one of 1 to 9, wherein at least one metal sulfide selected from the group consisting of the alkali metal sulfide and the alkaline earth metal sulfide is an alkali metal sulfide.
11. 11. The method for producing a modified metal sulfide according to 10, wherein the alkali metal sulfide is lithium sulfide.
12 A modified metal sulfide is produced by the method according to any one of 1 to 11 above,
Sulfurization for obtaining a sulfide-based solid electrolyte glass by bringing the modified metal sulfide into contact with one or more raw materials selected from the group consisting of phosphorus sulfide, elemental sulfur and elemental phosphorus and containing sulfur and phosphorus A method for producing a physical solid electrolyte glass.
13. A sulfide-based solid electrolyte glass is produced by the method described in 12 above,
A method for producing a sulfide-based solid electrolyte glass ceramic, wherein the sulfide-based solid electrolyte glass ceramic is obtained by heating and crystallizing the sulfide-based solid electrolyte glass.
14 Including a step of producing a metal hydrosulfide by contacting one or more metal sulfides selected from the group consisting of alkali metal sulfides and alkaline earth metal sulfides with a sulfide bond-containing compound in an organic solvent. Method for producing metal hydrosulfide.
15. 15. The method for producing a metal hydrosulfide according to 14, wherein the obtained metal hydrosulfide has a specific surface area of 20 m ² / g or more.
16. Lithium sulfide having a specific surface area of 20 m ² / g or more and a lithium hydroxide content of 0.5% by weight or less.

  According to the present invention, a novel modified metal sulfide production method capable of increasing the specific surface area of metal sulfide, and sulfide-based solid electrolyte glass and sulfide-based solid electrolyte glass ceramics using the same. A manufacturing method can be provided.

[Production method of modified metal sulfide]
In the method for producing a modified metal sulfide of the present invention, one or more metal sulfides selected from the group consisting of alkali metal sulfides and alkaline earth metal sulfides are contacted with a sulfide bond-containing compound in an organic solvent. By including a step of generating a metal hydrosulfide (first step), and a step of converting the metal hydrosulfide into a metal sulfide by dehydrosulfurization reaction (second step), A modified metal sulfide is obtained. Obtaining a metal sulfide having an increased specific surface area by the above method is called reforming.

  In the method of the present invention, a modified metal sulfide having a specific surface area larger than that of the original metal sulfide is produced by converting the metal sulfide into a metal hydrosulfide and returning the metal hydrosulfide to the metal sulfide. Can do.

  In the first step, one or more metal sulfides selected from the group consisting of alkali metal sulfides and alkaline earth metal sulfides are contacted with a sulfide bond-containing compound in an organic solvent at a first temperature, A step of obtaining a reactant, and a second step is a step of heating the reactant at a second temperature higher than the first temperature.

  The first temperature in the first step is preferably −20 ° C. to 150 ° C., more preferably 0 ° C. to 120 ° C., and further preferably 20 ° C. to 100 ° C. For example, they are 20 degreeC-90 degreeC, 20 degreeC-80 degreeC, 20 degreeC-75 degreeC, and 20 degreeC-60 degreeC. If the first temperature exceeds 150 ° C., the desired result may not be obtained. In addition, when the first temperature is lower than −20 ° C., when a low-boiling sulfide bond-containing compound is used, the pressure at the time of shifting to the second step described later is increased, which may be unfavorable for safety. .

The first step is preferably performed twice or more at different temperatures. At this time, the temperature of the second time is set higher than the temperature of the first time, the temperature of the third time is set higher than the temperature of the second time, and so on. Thereby, the amount of the metal hydroxide included in the modified metal sulfide can be further reduced. This is because the reaction with the metal hydroxide is promoted by increasing the specific surface area of the metal sulfide in the first treatment and reacting the metal sulfide with a high specific surface area in the second treatment higher than the temperature. Is.
The number of treatments at different temperatures is preferably two.

For example, in the first step, first, a metal sulfide is brought into contact with a sulfide bond-containing compound in an organic solvent at a temperature of 20 ° C. to 60 ° C. as a first temperature. Next, it is preferable to perform the treatment at a temperature higher than 60 ° C and lower than 100 ° C.
Specifically, from the viewpoint of reducing the amount of lithium hydroxide (LiOH), the first first temperature is preferably 40 ° C. to 60 ° C., then higher than 60 ° C. and 80 ° C. or lower. For example, the first first temperature is 45 ° C to 55 ° C, and then 65 ° C to 75 ° C.

The first pressure in the first step is preferably normal pressure (0.1 MPa) to 0.85 MPa, more preferably normal pressure (0.1 MPa) to 0.80 MPa, and normal pressure (0.1 MPa) to 0. More preferably, it is 50 MPa or less.
If the pressure is out of the above range, a separate safety device may be required, which may be undesirable in the process.

  The second temperature in the second step is higher than the first temperature, preferably 20 to 250 ° C, more preferably 50 to 210 ° C, and still more preferably 70 to 180 ° C. For example, they are 70 degreeC-150 degreeC and 90 degreeC-120 degreeC.

The second pressure in the second step is preferably normal pressure (0.1 MPa) or more and 0.85 MPa or less, more preferably normal pressure (0.1 MPa) or more and 0.80 MPa, and normal pressure (0.1 MPa) or more and 0. More preferably, it is 50 MPa or less.
If the pressure is out of the above range, a separate safety device may be required, which may be undesirable in the process.

When a metal sulfide (eg, Li ₂ S) and a sulfide bond-containing compound (eg, H ₂ S) are contacted at a first temperature, a metal hydrosulfide (eg, LiSH) is generated. The amount of metal hydrosulfide produced is, for example, 5 wt% or more and 80 wt% or less with respect to the total of metal sulfide and metal hydrosulfide. When the metal hydrosulfide is formed, the specific surface area can be increased.
Then, when the metal hydrosulfide is held again at a second temperature that is higher than the first temperature for a certain time, the de-H ₂ S reaction proceeds and returns to the original metal sulfide. And even if it returns to a metal sulfide, the specific surface area has increased compared with the metal sulfide of a starting material.
It is inferred that the specific surface area is increased by the first step and the second step.
Moreover, the quantity of the metal hydroxide to include can be reduced by this 1st process and a 2nd process. For example, when the metal sulfide is Li ₂ S, the amount of lithium hydroxide (LiOH) included can be reduced by the first step and the second step.

  In the modification, the metal sulfide is desirably 0.5 to 1000 parts by weight with respect to 100 parts by weight of the organic solvent. In addition, when a modifier (sulfide bond containing compound) is a gas at normal temperature or processing temperature, you may distribute | circulate and process.

  The reforming time (each of the first step and the second step) is preferably 5 minutes to 1 week, more preferably 10 minutes to 5 days. For example, it is 10 minutes or more and 72 hours or less, and 20 minutes or more and 48 hours or less.

  The reforming treatment (each of the first step and the second step) can be performed in either the continuous phase or the batch phase. In the case of a batch reaction, a general blade can be used for stirring, and an anchor blade, a fiddler blade, a helical blade, and a Max blend blade are preferable. In the laboratory scale, a stirrer with a stirrer is generally used. In the batch reaction, a reaction vessel using a ball mill can be used.

  The purity of the metal sulfide may decrease after the reforming process. In order to improve the purity, an additional treatment with hydrogen sulfide gas may be performed. At that time, if necessary, the sulfide bond-containing compound is removed in advance. The removal of the sulfide bond-containing compound can be carried out, for example, by heating under nitrogen or by substitution with a nonpolar solvent such as hydrocarbon (for example, aliphatic hydrocarbon, aromatic hydrocarbon). When using a metal sulfide in a slurry state in the step after the modification, it can be stored in a slurry state after performing this solvent replacement.

The modified product may be subjected to a drying treatment as necessary in order to remove the residual solvent. The drying treatment is preferably performed under a nitrogen stream or under vacuum. The drying temperature is preferably room temperature to 300 ° C. The dried metal sulfide may contain 0.01% to 30% by weight of an organic solvent.
The content of the organic solvent can be determined by gas chromatography after being dissolved in a suitable solvent such as toluene or alcohol.

According to the method of the present invention, the specific surface area of lithium sulfide can be increased without using a different element (for example, an oxygen atom resulting from an alcohol solvent) that is not included in the raw material used when producing the metal sulfide. .
Further, since no different element is used, measurement of the amount of impurities derived from the different element can be omitted.
When reforming with an alcohol solvent, a separate apparatus for using the alcohol solvent is required. However, in the method of the present invention, the same sulfide bond-containing compound as the sulfide bond-containing compound used in the production of the metal sulfide is used. For example, an apparatus used in the production of metal sulfide can be used.

[Metal sulfide]
Examples of metal sulfides include alkali metal sulfides and alkaline earth metal sulfides.

Examples of the alkali metal sulfide include lithium sulfide, sodium sulfide, potassium sulfide and the like. In consideration of the water content, examples of the alkali metal sulfide include anhydrous lithium sulfide, anhydrous sodium sulfide, anhydrous potassium sulfide, lithium sulfide hydrate, sodium sulfide hydrate, and potassium sulfide hydrate.
Examples of the alkaline earth metal sulfide include calcium sulfide and magnesium sulfide.
Of these, lithium sulfide and sodium sulfide are preferable.

  A metal sulfide may be used individually by 1 type, or may use 2 or more types together.

  Regarding the method for producing a metal sulfide, when the metal sulfide is lithium sulfide, specifically, the following (a) NMP method or (b) toluene method can be used.

(A) NMP method As a manufacturing method of lithium sulfide, it can obtain by refine | purifying the lithium sulfide manufactured by the following methods ac, for example. Among the following production methods, the method a or b is particularly preferable.
a. A method in which lithium hydroxide and hydrogen sulfide are reacted at 0 to 150 ° C. in an aprotic organic solvent to produce lithium hydrosulfide, and then this reaction solution is dehydrosulfurized at 150 to 200 ° C. 7-330312 gazette).
b. A method in which lithium hydroxide and hydrogen sulfide are reacted at 150 to 200 ° C. in an aprotic organic solvent to directly produce lithium sulfide (see JP-A-7-330312).
c. A method of reacting lithium hydroxide and a gaseous sulfur source at a temperature of 130 to 445 ° C. (see JP-A-9-283156).
In the methods a to c, since lithium hydroxide is used as a raw material, lithium hydroxide obtained may also contain lithium hydroxide as an impurity.

  There is no restriction | limiting in particular as a purification method of the lithium sulfide obtained as mentioned above. As a preferable purification method, for example, a purification method described in International Publication No. WO2005 / 40039 and the like can be mentioned. Specifically, the lithium sulfide obtained as described above is washed at a temperature of 100 ° C. or higher using an organic solvent.

The organic solvent used for washing is preferably an aprotic polar solvent, and more preferably, the aprotic organic solvent used for lithium sulfide production and the aprotic polar organic solvent used for washing are the same. .
Examples of the aprotic polar organic solvent preferably used for washing include aprotic polar organic compounds such as amide compounds, lactam compounds, urea compounds, organic sulfur compounds, cyclic organophosphorus compounds, Or it can use suitably as a mixed solvent. In particular, N-methyl-2-pyrrolidone (NMP) is selected as a good solvent.

The amount of the organic solvent used for washing is not particularly limited, and the number of times of washing is not particularly limited, but is preferably 2 or more. Cleaning is preferably performed under an inert gas such as nitrogen or argon.
Any organic solvent used for washing is preferably dehydrated.

(B) Toluene method Hydrogen sulfide gas is blown into a slurry composed of lithium hydroxide and a hydrocarbon-based organic solvent (for example, toluene), the lithium hydroxide and hydrogen sulfide are reacted, and water generated by the reaction is added to the slurry. The reaction is continued while removing water from the system, and after the water in the system has substantially disappeared, lithium sulfide can be produced by stopping the blowing of hydrogen sulfide and blowing in an inert gas (Japanese Patent Laid-Open No. 2010-163356). See the official gazette).

  In the present invention, the production of the metal sulfide and the production of the modified metal sulfide of the present invention may be carried out continuously. For example, (b) lithium sulfide is produced by the toluene method, and then the lithium sulfide may be contacted with the sulfide bond-containing compound in an organic solvent at a first temperature (first step of the present invention). ).

[Metal hydrosulfide]
The metal hydrosulfide is a hydrosulfide of the above metal sulfide, and examples thereof include alkali metal hydrosulfides and alkaline earth metal hydrosulfides.
Examples of the alkali metal hydrosulfide include lithium hydrosulfide, sodium hydrosulfide, potassium hydrosulfide and the like.
Examples of the alkaline earth metal hydrosulfide include calcium hydrosulfide and magnesium hydrosulfide.

[Modified metal sulfide]
The modified metal sulfide is a modified metal sulfide, and is a metal sulfide having a specific surface area increased by the first step described above.
Modified metal sulfides include modified alkali metal sulfides and modified alkaline earth metal sulfides.

In the modified metal sulfide, the specific surface area and the like are not particularly limited, but usually (i) the specific surface area measured by the BET method (gas adsorption method) is 1.0 m ² / g or more, or (ii) the pore volume is 0. 0.002 ml / g or more.
The modified metal sulfide has a specific surface area of, for example, 150% or more, 180% or more, or 200% or more of the specific surface area of the original metal sulfide. Although an upper limit is not specifically limited, For example, it is 400% or less.

The specific surface area can be measured by, for example, AUTOSORB 6 (manufactured by Sysmex Corporation). Further, the BET method may use nitrogen gas (nitrogen method) or krypton gas (krypton method). In addition, when a specific surface area is small, it measures normally by the krypton method. The specific surface area of the modified metal sulfide is preferably 1.2 m ² / g or more, and more preferably 1.5 m ² / g or more.

The pore volume can be measured with the same device as the specific surface area, and a value obtained by interpolating 0.99 from a measurement point where the relative pressure P / P ₀ is 0.99 or more can be used. The lower limit of measurement of the apparatus is 0.001 ml / g. The pore volume of the modified metal sulfide is preferably 0.003 ml / g or more.

[Organic solvent]
Organic solvents include hydrocarbon compounds, nitrile compounds, ether compounds, carbonyl compounds, ester compounds, carbonate compounds, amine compounds, alcohol compounds, amide compounds, silane compounds, halogen compounds, nitro compounds And solvents such as carbon compounds and carbon disulfide.
The hydrocarbon compound solvent (hydrocarbon solvent) is a solvent composed of carbon atoms and hydrogen atoms, and examples of the hydrocarbon solvent include saturated hydrocarbons, unsaturated hydrocarbons, and aromatic hydrocarbons.

  The boiling point of the organic solvent is preferably 200 ° C. or lower, and more preferably 180 ° C. or lower.

Examples of the saturated hydrocarbon solvent include pentane, hexane, 2-ethylhexane, heptane, octane, isooctane, decane, dodecane, cyclohexane, methylcyclohexane, IP solvent 1016 (manufactured by Idemitsu Kosan Co., Ltd.), and IP solvent 1620 (Idemitsu Kosan Co., Ltd.). Manufactured) and the like.
Examples of the unsaturated hydrocarbon include hexene, heptene, cyclohexene and the like.
Examples of aromatic hydrocarbons include benzene, toluene, xylene, ethylbenzene, decalin, 1,2,3,4-tetrahydronaphthalene, Ipsol 100 (manufactured by Idemitsu Kosan Co., Ltd.), Ipsol 150 (manufactured by Idemitsu Kosan Co., Ltd.), and the like. Is mentioned.

Moreover, as an aromatic hydrocarbon, it is a compound represented, for example by following formula (2).
Ph- (R) _n (2)
(In the formula, Ph is an aromatic hydrocarbon group, and each R is independently an alkyl group.
n is an integer selected from 1 to 5 (preferably an integer of 1 or 2))

In the formula (2), examples of the aromatic hydrocarbon group of Ph include a phenyl group and a naphthyl group. An aromatic hydrocarbon group having 6 to 24 carbon atoms is preferable, and an aromatic hydrocarbon group having 6 to 12 carbon atoms is more preferable.
In the formula (2), R is an alkyl group, and examples thereof include a methyl group, an ethyl group, and a propyl group. The number of carbon atoms of the alkyl group is preferably 1 or more and 24 or less, and more preferably 1 or more and 12 or less.
Examples of the aromatic hydrocarbon solvent represented by the formula (2) include toluene, xylene, and ethylbenzene.

  Examples of the nitrile compound include acetonitrile, propionitrile, isobutyronitrile, benzonitrile, malononitrile, succinonitrile, fumaronitrile and the like.

  Examples of the ether compounds include diethyl ether, cyclohexyl methyl ether, t-butyl methyl ether, dimethoxymethane, diethoxyethane, tetrahydrofuran, dioxane, diisopropyl ether, anisole and the like.

  Examples of the carbonyl compound include acetone, methyl ethyl ketone, and acetaldehyde.

  Examples of ester compounds include ethyl acetate.

  Examples of the carbonate compound include diethyl carbonate, ethylene carbonate, propylene carbonate, and the like.

  Examples of the amine compound include triethylamine, diethylamine, pyridine, N-methylpyrrolidone and the like.

  Examples of the alcohol compound include methanol, ethanol, propanol, n-butanol, and 2-butanol.

  Examples of amide compounds include dimethylformamide and dimethylacetamide.

  Examples of the silane compound include trimethylmethoxysilane, dimethyldimethoxysilane, tetramethoxysilane, tetraethoxysilane, and cyclohexylmethyldimethoxysilane.

  Examples of the halogen compound include methylene chloride, chloroform, dichloroethane, 1,1,2-trichloroethane, dichlorobenzene, hexafluorobenzene, trifluoromethylbenzene, and the like.

  Examples of the nitro compound include nitrobenzene, nitromethane, and nitropropane.

  The organic solvent is preferably a hydrocarbon solvent, more preferably a saturated hydrocarbon or an aromatic hydrocarbon.

  The above organic solvents may be used alone or in combination of two or more.

[Sulfide bond-containing compound]
Examples of the sulfide bond-containing compound (—S—bond-containing compound) used in the method for producing a modified metal sulfide of the present invention include hydrogen sulfide (H ₂ S), R—SH, R ¹ —S—R ^{2 and the} like. It is done.

  Specific examples of R-SH compounds include methanethiol, ethanethiol, isopropylthiol, n-propylthiol, n-butylthiol, isobutylthiol, t-butylthiol, cyclopentylthiol, n-hexylthiol, and n-octyl. Examples include thiol and dodecyl thiol.

Examples of the R ¹ -S—R ² compound include dimethyl sulfide, diethyl sulfide, diisopropyl sulfide, t-butylmethyl sulfide and the like.

  Of these, hydrogen sulfide is preferred as the sulfide bond-containing compound.

  The -S- bond-containing compound may be dehydrated or not dehydrated. The amount of water is preferably 50 ppm or less, more preferably 30 ppm or less, because the amount of metal hydroxide in the modified metal sulfide, which is a by-product of the amount of water, may be affected. The lower limit of the moisture content is not particularly limited, but is usually 0.1 ppm or more. The moisture content may be 0 ppm.

[Method for producing metal hydrosulfide]
In the method for producing a metal hydrosulfide according to the present invention, one or more metal sulfides selected from the group consisting of alkali metal sulfides and alkaline earth metal sulfides are contacted with a sulfide bond-containing compound in an organic solvent. Thus, a metal hydrosulfide is obtained.
By the method of the present invention, a metal hydrosulfide having a specific surface area of 20 m ² / g or more can be obtained.

  The temperature and pressure in the above process are the same as the temperature and pressure in the above first process. The metal sulfide, the sulfide bond-containing compound, and the organic solvent are the same as described above.

[Lithium sulfide produced by the modified metal sulfide production method]
For example, lithium sulfide having an increased specific surface area can be obtained by the method for producing a modified metal sulfide of the present invention. The lithium sulfide obtained by the method for producing a modified metal sulfide of the present invention has a specific surface area of 20 m ² / g or more and a lithium hydroxide content of 0.5% by weight or less.
The specific surface area is preferably 25 m ² / g or more.
The content of lithium hydroxide is preferably 0.4% by weight or less, for example, 0.3% by weight or less and 0.2% by weight or less.

[Sulfide-based solid electrolyte glass manufacturing process]
In the method for producing a sulfide-based glass solid electrolyte of the present invention, a sulfide-based solid electrolyte glass can be obtained by reacting the above-described modified metal sulfide and a raw material containing sulfur and phosphorus. Examples of the raw material containing sulfur and phosphorus include phosphorus sulfide, elemental sulfur, elemental phosphorus and the like alone or in combination. Specific examples include phosphorus sulfide, phosphorus sulfide and elemental sulfur, phosphorus sulfide and elemental phosphorus, elemental sulfur and elemental phosphorus, phosphorus sulfide, elemental sulfur and elemental phosphorus, and the like.
The reaction is carried out by a method via physical crushing using, for example, a ball mill apparatus or the like.

Examples of phosphorus sulfide include diphosphorus pentasulfide (P ₂ S ₅ ).
As long as diphosphorus pentasulfide is manufactured and sold industrially, it can be used without particular limitation. The purity is preferably 95% or more, and more preferably 99% or more. In place of P ₂ S ₅ , elemental phosphorus (P) and elemental sulfur (S) in a corresponding molar ratio can also be used. Simple phosphorus (P) and simple sulfur (S) can be used without particular limitation as long as they are industrially produced and sold.

When the batch mill reaction is used for the production of sulfide-based solid electrolyte glass, the reaction temperature is usually room temperature to 210 ° C, preferably 60 to 180 ° C.
When the temperature is high, the reaction and crystallization proceed at the same time, so the reaction rate does not increase and the residual metal sulfide increases, which is not preferable. Moreover, since reaction does not advance when temperature is low, it is unpreferable.

The reaction time is usually 1 to 200 hours, preferably 4 to 180 hours.
If the time is short, the reaction does not proceed. When the time is long, crystallization partially proceeds and performance such as ionic conductivity is lowered, which is not preferable.

  In the batch mill reaction, the same organic solvent as that used in the method for producing the modified metal sulfide of the present invention or a different organic solvent may be used as an additive. The addition amount of the additive is 0.1 part by weight to 10000 parts by weight, preferably 100 parts by weight to 5000 parts by weight with respect to 100 parts by weight of the metal sulfide.

  The reaction product may be recovered as it is after the reaction, but it can also be recovered in a slurry state by adding an organic solvent. Examples of the organic solvent for recovery include those similar to the hydrocarbon solvent in the organic solvent used in the above-described method for producing a modified metal sulfide of the present invention. This organic solvent is preferably dehydrated.

  In the next step, when the slurry reaction product is used as a dry powder, it is necessary to remove the organic solvent. This can be done at room temperature or in a warming treatment under vacuum or nitrogen flow. When performing on heating conditions, temperature is 40-200 degreeC normally, Preferably it is 50-160 degreeC. When the temperature is higher than the above range, crystallization proceeds and the conductivity performance decreases, which is not preferable. Further, when the temperature is low, the remaining solvent cannot be removed, which is not preferable.

  A sulfide-based solid electrolyte glass is obtained by the above drying treatment. The amount of the residual solvent is usually 5% by weight or less. Preferably it is 3 weight% or less. It may be 0% by weight. When the residual solvent is large, non-conductors in the electrolyte exist, which becomes a resistance component and may cause a decrease in battery performance.

[Method for producing sulfide-based solid electrolyte glass ceramics]
Crystallization of the above sulfide-based solid electrolyte glass can be performed by heat treatment, and sulfide-based solid electrolyte glass ceramics can be obtained. Thereby, the ionic conductivity of the sulfide-based solid electrolyte can be improved.
The heating temperature in crystallization is preferably 150 ° C. or higher and 400 ° C. or lower, more preferably 180 ° C. or higher and 320 ° C. or lower. The heating time is preferably 1 to 5 hours, particularly preferably 1.5 to 3 hours.
Further, the reaction product in the slurry state may be heated and crystallized with stirring.

<Manufacture of modified metal sulfides>
Production Example 1 (Production of NMP lithium sulfide)
(1) Production of lithium sulfide A 10-liter autoclave equipped with a stirring blade was charged with 3326.4 g (33.6 mol) of N-methyl-2-pyrrolidone (NMP) and 287.4 g (12 mol) of anhydrous lithium hydroxide, The temperature was raised to 130 ° C. at 300 rpm. After the temperature increase, hydrogen sulfide was blown into the liquid for 2 hours at a supply rate of 3 L / min.

  Subsequently, the temperature of the reaction solution was raised under a nitrogen stream (200 cc / min), and the produced lithium hydrosulfide was desulfurized to obtain lithium sulfide. As the temperature increased, water produced as a by-product due to the reaction between hydrogen sulfide and lithium hydroxide began to evaporate, and this water was condensed by a condenser and extracted out of the system. Water was distilled out of the system and the temperature of the reaction solution rose. When the temperature reached 180 ° C., the temperature increase was stopped and the temperature was kept constant. After the dehydrosulfurization reaction of lithium hydrosulfide (about 80 minutes) was completed, the reaction was terminated to obtain lithium sulfide.

(2) Purification of lithium sulfide After decanting NMP in the 500 mL slurry reaction solution (NMP-lithium sulfide slurry) obtained in (1), 100 mL of dehydrated NMP was added and stirred at 105 ° C. for about 1 hour. NMP was decanted at that temperature. The same operation was repeated 4 times in total. After completion of the decantation, 100 mL of dehydrated heptane was added, and the mixture was stirred at room temperature to remove the supernatant. This operation was repeated 5 times. The heptane slurry was collected and filtered under a nitrogen stream to remove the solvent. Vacuum drying was performed at 200 ° C. to obtain purified lithium sulfide.

  When the purity of the obtained purified lithium sulfide was calculated by potentiometric titration, it was 98.9% by weight (lithium hydroxide 0.1% by weight).

When the BET specific surface area (krypton method) was evaluated, the specific surface area was 0.04 m ² / g and the pore volume was 0.001 ml / g or less.

Production Example 2 (Production of toluene method lithium sulfide)
Under a nitrogen stream, 270 g of toluene (manufactured by Hiroshima Wako Co., Ltd.) was added to a 600 ml separable flask, and then 30 g of anhydrous lithium hydroxide (manufactured by Honjo Chemical Co., Ltd.) was added. Held on.

  The temperature was raised to 104 ° C. while blowing hydrogen sulfide (manufactured by Keishokai Co., Ltd.) into the slurry at a supply rate of 300 ml / min. From the separable flask, an azeotropic gas of water and toluene was continuously discharged. This azeotropic gas was dehydrated by condensing with a condenser outside the system. During this time, the same amount of toluene as the distilled toluene was continuously supplied to keep the reaction liquid level constant.

  The amount of water in the condensate gradually decreased, and no distillation of water was observed 6 hours after the introduction of hydrogen sulfide (the total amount of water was 22 ml). During the reaction, the solid was dispersed and stirred in toluene, and there was no moisture separated from toluene.

Thereafter, the hydrogen sulfide was switched to nitrogen and circulated at 300 ml / min for 1 hour.
The slurry solution was filtered. After filtration, vacuum drying was performed at 200 ° C. to obtain lithium sulfide.
As in Production Example 1, the purity of lithium sulfide, the residual amount of lithium hydroxide and the BET specific surface area were evaluated. The purity was 97.5% by weight, lithium hydroxide was 0.7% by weight, and the specific surface area was 13.2 m ² / g. The pore volume was 0.137 ml / g.

Example 1 (Production of modified lithium sulfide)
6.0 g of lithium sulfide obtained in Production Example 2 was weighed into a Schlenk bottle in a glove box. Under a nitrogen atmosphere, 120 ml of dehydrated toluene (manufactured by Wako Pure Chemical Industries, Ltd., water content 15 mass ppm) was added thereto. While flowing hydrogen sulfide gas at 100 ml / min, the mixture was stirred with a Teflon anchor blade for 4 hours at 50 ° C. (first temperature) and normal pressure (first step). The hydrogen sulfide gas was stopped and a part was sampled.

Here, when the slurry obtained by sampling after stopping the hydrogen sulfide gas was analyzed after drying, 44 wt% of lithium hydrosulfide was present, and the surface area of lithium hydrosulfide was 65 m ² / g.

After sampling, nitrogen was circulated, the bath temperature was raised to 120 ° C. (second temperature), and heat treatment was further performed at normal pressure for 2 hours (second step). After the temperature was lowered, nitrogen was passed to recover the modified lithium sulfide. Vacuum drying was performed at 200 ° C. to obtain modified lithium sulfide.
The modified lithium sulfide obtained after vacuum drying was evaluated for the purity of lithium sulfide, the residual amount of lithium hydroxide and the BET specific surface area in the same manner as in Production Example 1. The purity was 97.8% by weight and the lithium hydroxide content was 0.4. % By weight, specific surface area 27.2 m ² / g, pore volume 0.25 ml / g.

Example 2 (Pressurization method)
A modified lithium sulfide was produced in the same manner as in Example 1, except that a 500 ml pressure vessel with a stirrer was used instead of Schlenkbin, and the temperature in the first step was changed to 25 ° C. and the pressure was changed to 0.2 MPa. And evaluated.
The obtained modified lithium sulfide had a purity of 98.2% by weight, lithium hydroxide 0.5% by weight, a specific surface area of 25.0 m ² / g, and a pore volume of 0.22 ml / g.

Example 3
A modified lithium sulfide was produced and evaluated in the same manner as in Example 1 except that the lithium sulfide obtained in Production Example 1 was used instead of the lithium sulfide obtained in Production Example 2.
The obtained modified lithium sulfide had a purity of 99.1% by weight, lithium hydroxide 0.1% by weight, a specific surface area of 8.8 m ² / g, and a pore volume of 0.08 ml / g.

Comparative Example 1
The lithium sulfide obtained in Production Example 2 was used as the lithium sulfide of Comparative Example 1.

Comparative Example 2
The lithium sulfide obtained in Production Example 1 was used as the lithium sulfide of Comparative Example 2.

  Table 1 shows the specific surface areas of the lithium sulfides of Examples 1 to 3 and Comparative Examples 1 and 2.

Example 4
Modified lithium sulfide was produced and evaluated in the same manner as in Example 1 except that the reaction temperature (first temperature) in Example 1 was changed from 50 ° C. to 40 ° C.
The obtained modified lithium sulfide had a purity of 97.9% by weight, lithium hydroxide 0.4% by weight, a specific surface area of 26 m ² / g, and a pore volume of 0.22 ml / g.

Example 5
15.0 g of lithium sulfide obtained in Production Example 2 was weighed into a Schlenk bottle in a glove box. To this was added 300 ml of dehydrated toluene (manufactured by Wako Pure Chemical Industries, Ltd.) under a nitrogen atmosphere. The mixture was stirred with a Teflon anchor blade for 4 hours at 50 ° C. (first temperature A) and normal pressure while flowing hydrogen sulfide gas at 100 ml / min (first step A).

  Next, the mixture was stirred with a Teflon anchor blade for 2 hours at 70 ° C. (first temperature B) and normal pressure while flowing hydrogen sulfide gas at 100 ml / min (first step B).

The bath temperature was raised to 120 ° C. (second temperature), and nitrogen was circulated at normal pressure, followed by heat treatment for 2 hours (second step). After the temperature was lowered, nitrogen was passed to recover the modified lithium sulfide. Vacuum drying was performed at 200 ° C. to obtain modified lithium sulfide.
The modified lithium sulfide obtained after vacuum drying was evaluated for the purity of lithium sulfide, the residual amount of lithium hydroxide and the BET specific surface area in the same manner as in Production Example 1. The purity was 97.6 wt%, lithium hydroxide 0.2 % By weight, specific surface area of 29 m ² / g, and pore volume of 0.25 ml / g.

Example 6
It carried out continuously from manufacture example 2 to example 1, ie, without carrying out filtration processing on the way. Specifically, first, 350 g of toluene (manufactured by Hiroshima Wako Co., Ltd.) was added to a 600 ml separable flask under a nitrogen stream, followed by 35 g of anhydrous lithium hydroxide (manufactured by Honjo Chemical Co., Ltd.), and a full zone stirring blade at 350 rpm. While stirring, the temperature was maintained at 95 ° C.

  The temperature was raised to 104 ° C. while hydrogen sulfide (manufactured by Keishokai Co., Ltd.) was blown into the slurry at a supply rate of 400 ml / min. From the separable flask, an azeotropic gas of water and toluene was continuously discharged. This azeotropic gas was dehydrated by condensing with a condenser outside the system. During this time, the same amount of toluene as the distilled toluene was continuously supplied to keep the reaction liquid level constant.

  The amount of water in the condensate gradually decreased, and no distillation of water was observed 7 hours after the introduction of hydrogen sulfide (the total amount of water was 25 ml). During the reaction, the solid was dispersed and stirred in toluene, and there was no moisture separated from toluene.

  While flowing hydrogen sulfide gas at 100 ml / min, the mixture was stirred with a Teflon anchor blade for 4 hours at 50 ° C. (first temperature) and normal pressure (first step).

The bath temperature was raised to 120 ° C. (second temperature), and further heat treatment was performed at normal pressure for 2 hours (second step). After the temperature was lowered, nitrogen was passed to recover the modified lithium sulfide. Vacuum drying was performed at 200 ° C. to obtain modified lithium sulfide.
The modified lithium sulfide obtained after vacuum drying was evaluated for the purity of lithium sulfide, the residual amount of lithium hydroxide and the BET specific surface area in the same manner as in Production Example 1. The purity was 97.5% by weight, lithium hydroxide 0.5 % By weight, specific surface area 26 m ² / g, pore volume 0.23 ml / g.

Example 7
It carried out continuously from manufacture example 2 to example 5, ie, without carrying out filtration processing on the way. Specifically, first, 33.8 kg of anhydrous lithium hydroxide (Honjo Chemical Co., Ltd.) was charged under a nitrogen stream, and then 303.8 kg of toluene (Sumitomo Corporation) was added to a 500 L stainless steel reaction kettle. While stirring with a twin star stirring blade 131 rpm, the temperature was maintained at 95 ° C.
The temperature was raised to 107 ° C. while hydrogen sulfide (manufactured by Sumitomo Seika Co., Ltd.) was blown into the slurry at a supply rate of 100 L / min. An azeotropic gas of water and toluene was continuously discharged from the reaction kettle. This azeotropic gas was dehydrated by condensing with a condenser outside the system. During this time, the same amount of toluene as the distilled toluene was continuously supplied to keep the reaction liquid level constant.
The amount of water in the condensate gradually decreased, and water distilling was not observed 24 hours after the introduction of hydrogen sulfide. During the reaction, the solid was dispersed and stirred in toluene, and there was no moisture separated from toluene.
While flowing hydrogen sulfide gas at 40 L / min, the mixture was stirred with a twin star stirring blade at 50 ° C. (first temperature A) and normal pressure for 20 hours (first step A).
Next, the mixture was stirred with a twin star stirring blade at 70 ° C. (first temperature B) and normal pressure for 10 hours while flowing hydrogen sulfide gas at 40 L / min (first step B).
The reaction kettle jacket temperature was raised to 120 ° C. (second temperature), and nitrogen was circulated at normal pressure, followed by heat treatment for 16 hours (second step). After the temperature was lowered, nitrogen was passed to recover the modified lithium sulfide. Vacuum drying was performed at 100 ° C. to obtain modified lithium sulfide.
The modified lithium sulfide obtained after vacuum drying was evaluated for the purity of lithium sulfide, the residual amount of lithium hydroxide and the BET specific surface area in the same manner as in Production Example 1. The purity was 98.5% by weight, lithium hydroxide 0.1 The weight percent, specific surface area was 27 m ² / g, and pore volume was 0.31 ml / g.

<Manufacture of solid electrolyte glass>
Example 8
The modified lithium sulfide of Example 1 (1.0 g, 70 mol%) and diphosphorus pentasulfide (2.0 g, 30 mol%) were charged into a 0.1 L autoclave in a glove box. After sealing the autoclave, 30 ml of dehydrated toluene was added under nitrogen, and holding was performed under nitrogen. The mixture was heated and stirred in an oil bath and reacted at an internal temperature of 150 ° C. for 72 hours. After the temperature was lowered, nitrogen was circulated to recover the reaction product. Vacuum drying was performed at 150 ° C. to obtain a solid electrolyte glass.

About the obtained solid electrolyte glass, the residual ratio of lithium sulfide was measured.
After physical mixing at the same ratio as the charged amount, mortar mixing was performed and XRD measurement was performed. The peak heights at 27 °, 44 °, and 53 ° at this time were calculated as lithium sulfide remaining 100%.
As a result of measuring the XRD spectrum, a glass halo was observed, but a part of the raw material lithium sulfide was observed. From the peak height, the residual rate of raw material lithium sulfide was 12.2%.

Examples 9 and 10
A solid electrolyte glass was produced and evaluated in the same manner as in Example 8, except that the modified lithium sulfide shown in Table 2 was used instead of the modified lithium sulfide of Example 1 as the raw material lithium sulfide. The results are shown in Table 2.

Example 11
A solid electrolyte glass was produced and evaluated in the same manner as in Example 8, except that 1.15 g (75 mol%) of the modified lithium sulfide of Example 1 and 1.81 g (25 mol%) of diphosphorus pentasulfide were changed. did. The results are shown in Table 2.

Comparative Example 3
A solid electrolyte glass was produced and evaluated in the same manner as in Example 8, except that the lithium sulfide of Comparative Example 1 that was not subjected to the modification treatment of lithium sulfide was used instead of the modified lithium sulfide of Example 1. . The results are shown in Table 2.

Comparative Example 4
A solid electrolyte glass was produced and evaluated in the same manner as in Example 8 except that the modified lithium sulfide of Example 1 was used and the lithium sulfide of Comparative Example 2 that was not subjected to the modification treatment of lithium sulfide was used. . The results are shown in Table 2.
When the obtained solid electrolyte glass was visually observed, some coarse particles that could not be observed in Examples 8 to 11 were generated.

<Manufacture of solid electrolyte glass ceramics>
Example 12
The solid electrolyte glass of Example 8 was subjected to heat crystallization treatment at 300 ° C. for 2 hours under vacuum. The lithium ion conductivity of the crystallized solid electrolyte glass ceramic was 1.2 × 10 ⁻³ S / cm.

  The modified metal sulfide produced according to the present invention can be used as a raw material for medical and battery materials, particularly as a raw material for sulfide-based solid electrolytes. The sulfide-based solid electrolyte produced according to the present invention can be used for lithium secondary batteries and the like.

Although several embodiments and / or examples of the present invention have been described in detail above, those skilled in the art will appreciate that these exemplary embodiments and / or embodiments are substantially without departing from the novel teachings and advantages of the present invention. It is easy to make many changes to the embodiment. Accordingly, many of these modifications are within the scope of the present invention.
All the contents of the Japanese application specification that is the basis of the priority of Paris in this application are incorporated herein.

Claims (14)

  Including a step of producing a metal hydrosulfide by contacting one or more metal sulfides selected from the group consisting of alkali metal sulfides and alkaline earth metal sulfides with a sulfide bond-containing compound in an organic solvent. Method for producing metal hydrosulfide. The manufacturing method of the metal hydrosulfide of Claim 1 whose specific surface area of the obtained metal hydrosulfide is 20 m < ² > / g or more.   The method for producing a metal hydrosulfide according to claim 1 or 2, wherein the contact temperature in the organic solvent is -20C to 150C.   The method for producing a metal hydrosulfide according to claim 3, wherein the contact in the organic solvent is carried out twice or more at different temperatures, and the temperature is increased every time the contact is repeated.   The method for producing a metal hydrosulfide according to claim 4, wherein the contact in the organic solvent is carried out twice at different temperatures.   The method for producing a metal hydrosulfide according to claim 5, wherein the temperature at which the contact is different is 20 ° C. to 60 ° C. and higher than 60 ° C. and 100 ° C. or lower.   The method for producing a metal hydrosulfide according to claim 5, wherein the temperature at which the contact is different is 40 ° C. to 60 ° C. and higher than 60 ° C. and 80 ° C. or lower.   The method for producing a metal hydrosulfide according to any one of claims 1 to 7, wherein the pressure at the time of contact is from normal pressure to 0.85 MPa. Furthermore, it has the manufacturing process of the said metal sulfide,
The manufacturing method of the metal hydrosulfide in any one of Claims 2-8 which makes the said metal sulfide contact the said sulfide bond containing compound in the said organic solvent following the said manufacturing process.   The method for producing a metal hydrosulfide according to any one of claims 1 to 9, wherein the one or more metal sulfides selected from the group consisting of the alkali metal sulfide and the alkaline earth metal sulfide are alkali metal sulfides. .   The method for producing a metal hydrosulfide according to claim 10, wherein the alkali metal sulfide is lithium sulfide.   12. The metal hydrosulfide according to claim 1, wherein a production amount of the metal hydrosulfide is 5 wt% or more and 80 wt% or less with respect to a total of the metal sulfide and the metal hydrosulfide. Manufacturing method. A metal hydrosulfide having a specific surface area of 20 m ² / g or more.   The metal hydrosulfide according to claim 13 and a metal sulfide, wherein the content of the metal hydrosulfide is 5 wt% or more and 80 wt% or less with respect to the total of the metal sulfide and the metal hydrosulfide. Is a mixed powder.