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CN-121974300-A - Liquid phase indirect preparation method of high-purity lithium sulfide

CN121974300ACN 121974300 ACN121974300 ACN 121974300ACN-121974300-A

Abstract

The invention discloses a liquid phase indirect preparation method of high-purity lithium sulfide, and belongs to the field of fine chemical engineering. According to the preparation method, firstly, metallic lithium is utilized to react with high-purity naphthalene in an ether solvent under anhydrous oxygen-free and argon atmosphere at low temperature to generate naphthyl lithium, then high-purity hydrogen sulfide and naphthyl lithium are introduced to react at room temperature to generate lithium hydrosulfide, then the lithium hydrosulfide is converted at 100-150 ℃ to generate lithium sulfide, the lithium sulfide is filtered in the argon atmosphere after cooling, and the high-purity finely-dispersed lithium sulfide is obtained through washing and vacuum drying by using the ether solvent, wherein the purity is more than 99.99%. Compared with the prior art, the lithium sulfide obtained by the preparation method is powder with high purity, uniform granularity, fine dispersion and good fluidity, has stable process and product quality, can be suitable for the production of industrial-scale high-purity lithium sulfide, and has good popularization and application values.

Inventors

  • LI JINGJING
  • ZENG GANG
  • HU PEIPEI
  • JI HONGWEI

Assignees

  • 成都惠恩精细化工有限责任公司

Dates

Publication Date
20260505
Application Date
20260121

Claims (10)

  1. 1. The liquid phase indirect preparation method of the high-purity lithium sulfide is characterized by comprising the following steps of: S1, dissolving naphthalene with purity of more than 99.9% in an ether solvent under the condition of anhydrous and anaerobic inert gas to form naphthalene solution; s2, adding metal lithium into the naphthalene solution at the temperature of 0-25 ℃ under the atmosphere of inert gas, and fully stirring for reaction to generate a naphthalene lithium solution; S3, maintaining an inert gas atmosphere and introducing hydrogen sulfide gas with purity of more than 99.9% into the naphthyl lithium solution under stirring to react to generate lithium sulfide, stopping introducing hydrogen sulfide after the system does not absorb hydrogen sulfide any more, continuously introducing the inert gas, stirring, raising the temperature of the system to 100-150 ℃, and continuously stirring and reacting for 3-6 hours to promote the generation of lithium sulfide; S4, stirring and cooling to room temperature in an inert gas atmosphere after the reaction is finished, filtering, washing and vacuum drying to obtain a lithium sulfide product with the purity of more than 99.99%.
  2. 2. The liquid phase indirect preparation method of high-purity lithium sulfide according to claim 1, wherein the ether solvent in the step S1 is ethylene glycol dimethyl ether, propylene glycol dimethyl ether, polyethylene glycol dimethyl ether, 1, 4-dioxane and/or 1, 3-dioxane; the mass ratio of the ether solvent to the naphthalene is 5:1-10:1.
  3. 3. The method for the liquid phase indirect preparation of high purity lithium sulfide according to claim 1 or 2, wherein step S2 maintains an excess of naphthalene, and the molar ratio of metallic lithium to naphthalene is preferably 1:1 to 1:1.2.
  4. 4. The method for indirectly preparing high-purity lithium sulfide according to claim 3, wherein the reaction temperature of the metallic lithium and naphthalene in the step S2 is 0-15 ℃ and the reaction time is 15-30 hours.
  5. 5. The method for the indirect liquid phase preparation of high purity lithium sulfide according to claim 4, wherein the metallic lithium in step S2 is lithium particles.
  6. 6. The method for the liquid phase indirect production of high purity lithium sulfide according to claim 1 or 2, wherein the water content of the hydrogen sulfide gas in step S3 is <20ppm.
  7. 7. The method for the indirect liquid phase preparation of high purity lithium sulfide according to claim 6, wherein, Hydrogen sulfide feed rate to maintain system temperature no more than 50 ℃; after the system does not absorb the hydrogen sulfide gas, stirring and reacting for 4-6 hours at 120-150 ℃.
  8. 8. The method for the liquid phase indirect preparation of high purity lithium sulfide according to claim 1 or 2, wherein step S4 uses an ether-type detergent with a lower boiling point, preferably tetrahydrofuran; the consumption of the ether detergent is 5-10 times of the quality of the lithium sulfide product.
  9. 9. The liquid phase indirect preparation method of high-purity lithium sulfide according to claim 1 or 2, wherein the vacuum degree of vacuum drying in the step S4 is-0.098+/-0.02 MPa, the drying temperature is 120-160 ℃, and the dynamic drying is carried out for 4-10 hours.
  10. 10. The method for the indirect liquid phase preparation of high purity lithium sulfide according to claim 1 or 2, wherein the average particle size of the lithium sulfide product is less than 20 μm, the purity is more than 99.99%, and the total content of oxygen-containing impurities is less than 100ppm.

Description

Liquid phase indirect preparation method of high-purity lithium sulfide Technical Field The invention relates to the field of fine chemical industry, and particularly provides a liquid phase indirect preparation method of high-purity lithium sulfide. Background Lithium sulfide (Li 2 S) is a key material for solid-state lithium ion battery electrolytes, and is a foundation for solid-state battery development. The preparation of high-purity lithium sulfide is quite difficult due to the characteristics of easy oxidation, easy hydrolysis and the like. There are many research institutions and enterprises at home and abroad to put in a great deal of manpower and material resources to research and develop the synthetic process technology of the high-purity lithium sulfide material. The patent document of publication No. CN112678781 discloses a process technology for preparing lithium sulfide by a mechanical grinding method, hydrazine hydrate is required to be used for reduction in the process, the conversion rate of a lithium source is 80%, and the purity of the lithium sulfide is 95%. Patent document CN117163922 discloses a method for synthesizing lithium sulfide by ball milling metallic lithium, sulfur and a lithium-containing additive by a wet method at 140-160 ℃ and then calcining at 600 ℃. Patent document CN112551491 discloses a technology for obtaining lithium sulfide by mixing and reacting lithium source and sulfur source materials in alcohol solution, and then heating and crystallizing in a tube furnace and drying in vacuum, wherein the scale is gram-scale experimental synthesis. The patent document of publication No. CN115535968 discloses a process for synthesizing lithium sulfide by high-temperature melting reaction, alcoholysis and high-temperature calcination of sulfur and lithium hydroxide, which still belongs to gram-scale experiment scale, and the product contains a small amount of lithium disulfide. The patent document of publication No. CN116354315 discloses a process technology for synthesizing lithium sulfide by a solid-phase melting method. And (3) carrying out melt reaction on lithium hydroxide and thiourea in an atmosphere of 500-600 ℃ and hydrogen sulfide to obtain lithium sulfide with ICP analysis purity of 95%. A process for producing lithium sulfide by a high-temperature melt reduction method is disclosed in patent document publication No. CN 115734942. And reacting lithium sulfate, lithium sulfite, lithium thiosulfate and the like with reducing agents such as carbon, graphite, charcoal, bamboo charcoal and the like in a reducing atmosphere of 750-880 ℃ hydrogen, carbon monoxide, hydrogen sulfide and the like to synthesize the lithium sulfide. Patent document CN114455550 discloses a method of obtaining lithium sulfide by reacting lithium hydroxide with a sulfur source compound such as thioacetamide, dithiocyano methane, mercaptosuccinic acid, cysteine, etc. in a solution, and using MDEA as a hydrogen sulfide release inhibitor, performing a wet ball milling reaction, and then calcining at a high temperature. Patent document CN1871177 discloses a lithium sulfide synthesis method in which lithium hydroxide and hydrogen sulfide are reacted in an aprotic organic solvent, and the reaction is performed with an organic solvent at 100 ℃ or higher, and the aprotic organic solvent is NMP. The content of sulfur oxide in the lithium sulfide is less than 0.15%, and the LMAB is less than 0.1%. The technology for synthesizing lithium sulfide by a high-temperature carbothermic method is disclosed in the patent document of publication No. CN 115279688. And reducing the raw materials of lithium sulfate and active carbon in a nitrogen atmosphere or an argon atmosphere at 800-850 ℃ to obtain the lithium sulfide with the yield of 98% and the purity of more than 98%. The patent document of publication No. CN1162166552 discloses a method for producing lithium sulfide by firstly generating tan lithium nitride by using metal powder and high-purity nitrogen in a glove box and then grinding the tan lithium nitride with high-purity sulfur, wherein the yield is more than 98%. Patent document CN1145538384 discloses a method for obtaining lithium sulfide by reacting sulfur and metallic lithium in aromatic hydrocarbon solvent, and then reducing and calcining at 280-350 ℃ with purity of 99.6%. The technology for synthesizing lithium sulfide by a liquid phase direct vulcanization method is disclosed in the patent document of publication No. CN 114394608. Dissolving metallic lithium in a cyclic ether solvent in a glove box, adding a sulfur solution, reacting at a low temperature to obtain lithium sulfide, and separating and refining. A method for synthesizing lithium sulfide by a solid-phase ball milling method is disclosed in patent document of publication No. CN 112125322. Lithium source materials such as lithium amide, lithium imide, lithium nitride) and sulfur sources such as sulfur are ground in a ball mill in a hydrog