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CN-122010059-A - Preparation method of industrial lithium hydroxide and sodium sulfide synthesized lithium sulfide, preparation method of solid electrolyte and solid battery

CN122010059ACN 122010059 ACN122010059 ACN 122010059ACN-122010059-A

Abstract

The invention provides a preparation method of industrial lithium hydroxide and sodium sulfide synthesized lithium sulfide, a preparation method of solid electrolyte and a solid battery, wherein the preparation method of industrial lithium hydroxide and sodium sulfide synthesized lithium sulfide comprises the following steps of dissolving industrial lithium hydroxide raw materials, sequentially oxidizing, adding sodium sulfide and a flocculating agent for precipitation and filtering, sequentially adding sodium carbonate and barium nitrate for impurity removal and filtering to obtain a lithium hydroxide purifying solution; the method comprises the steps of reacting sodium sulfide solid with dilute sulfuric acid to obtain hydrogen sulfide gas, introducing the hydrogen sulfide gas into lithium hydroxide purifying liquid to react to obtain lithium sulfide slurry, evaporating and concentrating the lithium sulfide slurry, crystallizing, centrifugally separating, calcining the crystal in vacuum, and crushing to obtain lithium sulfide powder. Through oxidation conversion, chemical precipitation and crystallization purification, the high efficiency and deep removal of impurities are realized, the problems of complex raw material components and difficult separation are solved, and the purity of lithium sulfide is improved.

Inventors

  • LIU YINING
  • LI HONGJIAN
  • WU JIAWEI
  • DUAN ZHICHAO
  • LIAO YIPENG

Assignees

  • 深圳智圣能源科技有限公司

Dates

Publication Date
20260512
Application Date
20260209

Claims (10)

  1. 1. The preparation method for synthesizing lithium sulfide by using industrial lithium hydroxide and sodium sulfide is characterized by comprising the following steps: adding an industrial grade lithium hydroxide raw material into deionized water to obtain lithium hydroxide solution; adding a hydrogen peroxide solution into the lithium hydroxide solution for oxidation to obtain an oxidation premix solution; adding sodium sulfide and a flocculating agent into the oxidation premix solution for precipitation and filtering to obtain impurity-removing filtrate; sequentially adding sodium carbonate and barium nitrate into the impurity removal filtrate to remove impurities and filtering to obtain lithium hydroxide purified liquid; Reacting sodium sulfide solid with dilute sulfuric acid under heating condition to obtain hydrogen sulfide gas; heating the lithium hydroxide purifying liquid under the protection of inert atmosphere, and introducing the hydrogen sulfide gas into the lithium hydroxide purifying liquid for reaction to obtain lithium sulfide slurry; evaporating, concentrating and crystallizing the lithium sulfide slurry in an inert atmosphere, and centrifugally separating to obtain lithium sulfide crystals and mother liquor; And carrying out vacuum calcination on the lithium sulfide crystal to obtain a lithium sulfide material, and crushing the lithium sulfide material to obtain lithium sulfide powder.
  2. 2. The method for preparing industrial grade lithium hydroxide and sodium sulfide composite lithium sulfide according to claim 1, wherein the purity of the industrial grade lithium hydroxide raw material is more than 98%, and the concentration of the lithium hydroxide solution is 10-20 wt%.
  3. 3. The method for preparing industrial lithium hydroxide and sodium sulfide composite lithium sulfide according to claim 1, wherein the oxidation time is 30min-60min after the hydrogen peroxide solution is added.
  4. 4. The method for preparing industrial grade lithium hydroxide and sodium sulfide synthesized lithium sulfide according to claim 1, wherein sodium sulfide solid and dilute sulfuric acid are reacted under heating condition to obtain hydrogen sulfide gas, the concentration of the dilute sulfuric acid is 20wt% to 35wt%, the molar ratio of sodium sulfide to sulfuric acid is 1:1.03 to 1:1.15, and the heating temperature is less than 60 ℃.
  5. 5. The method for preparing industrial grade lithium hydroxide and sodium sulfide synthetic lithium sulfide according to claim 1, wherein the temperature of the lithium hydroxide purifying liquid is raised under the protection of inert atmosphere, the hydrogen sulfide gas is introduced into the lithium hydroxide purifying liquid for reaction, when the temperature is raised to 103-110 ℃ to obtain lithium sulfide slurry, the hydrogen sulfide introducing speed is 0.3-2L/min, and the lithium hydroxide purifying liquid is stirred and reacted for 5-8 h.
  6. 6. The method of claim 5, wherein the molar ratio of lithium hydroxide to hydrogen sulfide in the lithium hydroxide solution to hydrogen sulfide gas is 2:1.02 to 2:1.04.
  7. 7. The method for preparing industrial lithium hydroxide and sodium sulfide composite lithium sulfide according to claim 1, wherein the vacuum calcination temperature is 180-400 ℃, the calcination time is 6-10 h, and the vacuum degree of vacuum calcination is less than or equal to 30Pa.
  8. 8. The method for preparing industrial lithium hydroxide and sodium sulfide composite lithium sulfide according to claim 1, wherein the lithium sulfide slurry is evaporated, concentrated and crystallized in an inert atmosphere, and the lithium sulfide crystal and mother liquor are obtained after centrifugal separation, wherein the evaporating, concentrating and crystallizing temperature is 105-115 ℃, and the crystallizing temperature is 58-65 ℃.
  9. 9. A sulfide solid electrolyte characterized in that a lithium sulfide powder is obtained by the preparation method of synthesizing lithium sulfide from industrial-grade lithium hydroxide and sodium sulfide according to any one of claims 1 to 8, and the lithium sulfide powder is synthesized by reacting with a phosphide or halide raw material to obtain the sulfide solid electrolyte.
  10. 10. A solid state battery comprising the sulfide solid state electrolyte of claim 9.

Description

Preparation method of industrial lithium hydroxide and sodium sulfide synthesized lithium sulfide, preparation method of solid electrolyte and solid battery Technical Field The disclosure relates to the field of lithium battery material production, in particular to a preparation method of industrial lithium hydroxide and sodium sulfide synthesized lithium sulfide, a solid electrolyte preparation method and a solid battery. Background Lithium sulfide is an important inorganic chalcogenide compound, has excellent ion conductivity and chemical stability, and has wide application prospect in various fields. In the field of solid state batteries, lithium sulfide is a key precursor for preparing high performance sulfide solid state electrolytes, the purity of which directly affects the ionic conductivity, interfacial stability, and cycle life and safety of the final battery. With the rapid development of new energy industries, particularly solid-state battery technologies, the demand for high-purity lithium sulfide is increasing, and the purity requirement is also increasing, which generally needs to reach more than 99.95%, even higher. Lithium hydroxide or lithium carbonate is utilized to react with hydrogen sulfide gas to generate lithium sulfide, the raw materials are relatively easy to obtain, but the purity requirement on the raw materials of lithium hydroxide or lithium carbonate is higher. The source of the industrial lithium hydroxide raw material is obtained through a lithium ore extraction and salt lake lithium extraction process, if the industrial lithium hydroxide raw material is used, impurities such as iron, calcium, magnesium, silicon, potassium, sodium, sulfate radical and the like are contained in the industrial lithium hydroxide raw material, and the raw material is complex and unstable in composition and possibly contains various impurities. This complexity is difficult to handle with a single or simple purification process, resulting in purity of the lithium sulfide product being produced, which is difficult to meet the requirements of high-end battery applications. Transferring the molten lithium hydroxide into a reaction device, continuously introducing mixed gas containing hydrogen sulfide into the molten lithium hydroxide from a bottom gas inlet of the reaction device, stirring and reacting at 470-650 ℃, discharging a reaction product into a high-temperature centrifuge after the reaction is finished, centrifuging at 500-600 ℃, returning a lithium hydroxide melt obtained by centrifugation to the reaction device, and obtaining precipitate by centrifugation, namely the micro-powder grade lithium sulfide. According to the scheme, crystal water, organic residual substances and low-boiling-point impurities in lithium hydroxide can not be removed, impurities such as iron, calcium, magnesium, silicon, potassium, sodium and sulfate contained in industrial-grade raw materials can not be purified, and impurities such as iron, calcium, magnesium, silicon, potassium, sodium and sulfate can not be separated by adopting high-temperature centrifugal separation of lithium hydroxide melt and lithium sulfide, so that purity of the obtained lithium sulfide is influenced. Disclosure of Invention The purpose of the present disclosure is to overcome the shortcomings in the prior art, and to provide a method for preparing industrial lithium hydroxide and sodium sulfide synthesized lithium sulfide and a method for preparing solid electrolyte, and a solid battery, wherein impurities are efficiently and deeply removed. The aim of the disclosure is achieved by the following technical scheme: the preparation method of the industrial lithium hydroxide and sodium sulfide synthesized lithium sulfide comprises the following steps: adding an industrial grade lithium hydroxide raw material into deionized water to obtain lithium hydroxide solution; adding a hydrogen peroxide solution into the lithium hydroxide solution for oxidation to obtain an oxidation premix solution; adding sodium sulfide and a flocculating agent into the oxidation premix solution for precipitation and filtering to obtain impurity-removing filtrate; sequentially adding sodium carbonate and barium nitrate into the impurity removal filtrate to remove impurities and filtering to obtain lithium hydroxide purified liquid; Reacting sodium sulfide solid with dilute sulfuric acid under heating condition to obtain hydrogen sulfide gas; heating the lithium hydroxide purifying liquid under the protection of inert atmosphere, and introducing the hydrogen sulfide gas into the lithium hydroxide purifying liquid for reaction to obtain lithium sulfide slurry; evaporating, concentrating and crystallizing the lithium sulfide slurry in an inert atmosphere, and centrifugally separating to obtain lithium sulfide crystals and mother liquor; And carrying out vacuum calcination on the lithium sulfide crystal to obtain a lithium sulfide material, and crushing the lithium sulfid