CN-122010057-A - Liquid phase synthesis method of lithium sulfide, sulfide-based solid electrolyte and lithium ion battery

CN122010057ACN 122010057 ACN122010057 ACN 122010057ACN-122010057-A

Abstract

The embodiment of the application discloses a liquid phase synthesis method of lithium sulfide, sulfide-based solid electrolyte and a lithium ion battery, wherein the method comprises the steps of preparing lithium chloride and sulfur salt into a first suspension containing lithium hydrosulfide, and filtering to obtain a first lithium hydrosulfide solution; the first lithium hydrosulfide solution is cooled at the first temperature, so that crystals are precipitated from the second lithium hydrosulfide solution, meanwhile, the solubility of the solution is further reduced by the precipitated water, impurity ions are further precipitated, the impurity ions in the second lithium hydrosulfide solution are effectively reduced, and the impurity content in the subsequently prepared lithium sulfide is low.

Inventors

Xiong Hougao
LIU QIANG
WANG DONGWEI
LUO WEN
Tu Huazhen
SHI QIHUA
WANG JINTAO
LV ZHENGZHONG

Assignees

湖北金泉新材料有限公司

Dates

Publication Date: 20260512
Application Date: 20251226

Claims (10)

1. A liquid phase synthesis method of lithium sulfide, characterized by comprising the following steps: preparing lithium chloride and a sulfur salt into a first suspension containing lithium hydrosulfide, and filtering to obtain a first lithium hydrosulfide solution; Cooling the first lithium hydrosulfide solution at a first temperature, and filtering to obtain a second lithium hydrosulfide solution; and desulfurizing the second lithium hydrosulfide solution under inert atmosphere, and filtering to obtain the lithium sulfide.
2. The liquid phase synthesis method of lithium sulfide according to claim 1, wherein, A step of preparing a first suspension containing lithium bisulfide from lithium chloride and a sulfur salt, comprising: dissolving lithium chloride in an organic solvent to obtain a lithium chloride solution; And adding a sulfur salt into the lithium chloride solution, and reacting at a second temperature to obtain a first suspension containing lithium hydrosulfide, wherein the second temperature is higher than the first temperature.
3. The liquid phase synthesis method of lithium sulfide according to claim 2, wherein, The value of the first temperature ranges from-20 o C to 10 o C, and/or The value of the second temperature ranges from 50 o C to 140 o C.
4. The liquid phase synthesis method of lithium sulfide according to claim 2, wherein, The organic solvent comprises a polar aprotic organic solvent; wherein the polar aprotic organic solvent comprises at least one of dimethyl sulfoxide, dimethylformamide, N-dimethylacetamide, 3-methoxy-N, N-dimethylpropionamide, N-alkyl caprolactam and N-alkyl pyrrolidone.
5. The liquid phase synthesis method of lithium sulfide according to claim 1, wherein, Cooling the first lithium hydrosulfide solution at a first temperature to obtain a second suspension; wherein the second suspension comprises a crystalline body containing a chloride salt and a lithium bisulfide solution, and/or And desulfurizing the second lithium hydrosulfide solution under an inert atmosphere to obtain a third suspension, wherein the third suspension comprises lithium sulfide, lithium chloride solution and lithium hydrosulfide solution.
6. The liquid phase synthesis method of lithium sulfide according to claim 1, wherein, The molar ratio of lithium chloride to sulfur salt is in the range of 1 to 1.5, and/or The sulfur salts include hydrosulfide salts; Wherein the hydrosulfide salt comprises at least one of potassium hydrosulfide and sodium hydrosulfide.
7. The liquid phase synthesis method of lithium sulfide according to claim 1, wherein, The desulfurization temperature is 150 o to 200 o C, and/or The desulfurization time is 0.5h to 20h.
8. The liquid phase synthesis method of lithium sulfide according to claim 1, wherein, The lithium sulfide is single crystal particles, and/or The D50 particle diameter of the lithium sulfide ranges from 7 mu m to 8 mu m, and/or In the lithium sulfide, the content of the metal base is more than 99.92 percent, and the content of the impurity ions is less than 200ppm.
9. A sulfide-based solid electrolyte characterized in that, The sulfide-based solid electrolyte is prepared by the liquid phase synthesis method of lithium sulfide according to any one of claims 1 to 8.
10. A lithium ion battery is characterized in that, The lithium ion battery comprising the sulfide-based solid electrolyte of claim 9.

Description

Liquid phase synthesis method of lithium sulfide, sulfide-based solid electrolyte and lithium ion battery Technical Field The application relates to the technical field of battery material preparation, in particular to a liquid phase synthesis method of lithium sulfide, sulfide-based solid electrolyte and a lithium ion battery. Background Lithium sulfide (Li 2 S) is an important inorganic lithium compound, is a key precursor material for preparing sulfide-based solid electrolyte, and is widely applied to new-generation energy storage devices with high energy density and high safety, such as all-solid-state lithium ion batteries. Sulfide-based solid electrolytes (such as Li 2S-P2S5 systems) have advantages of high ionic conductivity, wide electrochemical window, and good compatibility with electrode materials, and have been actively used in all-solid batteries in recent years. However, lithium sulfide does not have a natural mineral source in nature, and must be prepared by a synthetic method, and the uniformity of morphology and impurity content directly affect the battery performance. Disclosure of Invention The application provides a liquid phase synthesis method of lithium sulfide, sulfide-based solid electrolyte and a lithium ion battery, and aims to ensure that the synthesized lithium sulfide has lower impurity content. The application provides a liquid phase synthesis method of lithium sulfide, which comprises the following steps: preparing lithium chloride and a sulfur salt into a first suspension containing lithium hydrosulfide, and filtering to obtain a first lithium hydrosulfide solution; Cooling the first lithium hydrosulfide solution at a first temperature, and filtering to obtain a second lithium hydrosulfide solution; and desulfurizing the second lithium hydrosulfide solution under inert atmosphere, and filtering to obtain the lithium sulfide. Optionally, in some embodiments of the application, the step of forming the lithium chloride, the sulfur salt into a first suspension comprising lithium bisulfide comprises: dissolving lithium chloride in an organic solvent to obtain a lithium chloride solution; And adding a sulfur salt into the lithium chloride solution, reacting at a second temperature, and filtering to obtain a first suspension containing lithium hydrosulfide, wherein the second temperature is higher than the first temperature. Optionally, in some embodiments of the application, the first temperature has a value in the range of-20 o C to 10 o C, and/or The value of the second temperature ranges from 50 o C to 140 o C. Alternatively, in some embodiments of the application, the organic solvent comprises a polar aprotic organic solvent; wherein the polar aprotic organic solvent comprises at least one of dimethyl sulfoxide, dimethylformamide, N-dimethylacetamide, 3-methoxy-N, N-dimethylpropionamide, N-alkyl caprolactam and N-alkyl pyrrolidone. Optionally, in some embodiments of the application, the first lithium bisulfide solution is cooled at a first temperature to obtain a second suspension; wherein the second suspension comprises a crystalline body containing a chloride salt and a lithium bisulfide solution, and/or And desulfurizing the second lithium hydrosulfide solution under an inert atmosphere to obtain a third suspension, wherein the third suspension comprises lithium sulfide, lithium chloride solution and lithium hydrosulfide solution. Optionally, in some embodiments of the application, the molar ratio of lithium chloride to sulfur salt is in the range of 1 to 1.5, and/or The sulfur salts include hydrosulfide salts; Wherein the hydrosulfide salt comprises at least one of potassium hydrosulfide and sodium hydrosulfide. Optionally, in some embodiments of the application, the desulfurization is performed at a temperature of 150 o C to 200 o C, and/or The desulfurization time is 0.5h to 20h. Optionally, in some embodiments of the application, the lithium sulfide is single crystal particles, and/or The D50 particle diameter of the lithium sulfide ranges from 7 mu m to 8 mu m, and/or In the lithium sulfide, the content of the metal base is more than 99.92 percent, and the content of the impurity ions is less than 200ppm. Correspondingly, the application also provides a sulfide-based solid electrolyte, which is prepared by adopting the liquid phase synthesis method of the lithium sulfide. In addition, the application also provides a lithium ion battery, which comprises the sulfide-based solid electrolyte. The synthesis method comprises the steps of preparing lithium chloride and a sulfur salt into a first suspension containing lithium bisulfide, filtering to obtain a first lithium bisulfide solution, and cooling the first lithium bisulfide solution at a first temperature to facilitate the precipitation of crystals of a second lithium bisulfide solution, wherein the precipitation part of water further reduces the solubility of the solution, and the impurity ions in the second lithium bi