Lithium sulfide solid electrolyte material containing silver iodide and silver chloride and preparation method thereof

Abstract

The invention discloses a lithium sulfide solid electrolyte material containing silver iodide and silver chloride and a preparation method thereof. The preparation method comprises the following steps: 1) weighing 35 to 50% of lithium sulfide and the balance of phosphorus sulfide according to mass percentage under protective atmosphere condition and evenly mixing to obtain a lithium sulfur phosphorus ternary mixture; 2) taking the lithium sulfur phosphorus ternary mixture, silver iodide and silver chloride under protective atmosphere and safe red light condition to be ball milled to obtain an amorphous-state lithium sulfur phosphorus mixture containing the silver iodide and the silver chloride, wherein the silver iodide is 2 to 6% of the mass of the lithium sulfur phosphorus ternary mixture and the silver chloride is 1 to 5% of the mass of the lithium sulfur phosphorus ternary mixture; 3) sealing the obtained amorphous-state lithium sulfur phosphorus mixture of the silver iodide and the silver chloride under the protective atmosphere and red light condition and warming to 80 to 180 DEG C under vacuum or protective atmosphere condition to perform thermal treatment to obtain the lithium sulfide system solid electrolyte material containing the silver iodide and the silver chloride. The preparation method disclosed by the invention can effectively improve the ionic conduction performance of the obtained lithium sulfide system solid electrolyte material.

Description

technical field [0001] The invention relates to a lithium sulfide solid electrolyte material, in particular to a lithium sulfide solid electrolyte material containing silver iodide and silver chloride and a preparation method thereof. Background technique [0002] Lithium-ion batteries with high voltage and high energy density have been widely used in consumer electronics such as laptop computers and mobile phones. In recent years, lithium batteries with high energy density have shown more and more important market prospects as power batteries for electric vehicles, and have been considered as ideal energy conversion devices for the development of the 21st century. A general lithium-ion battery is composed of a positive electrode, a negative electrode, a diaphragm, an organic electrolyte, and a sealed casing. Major safety accidents such as fires caused by flammable organic electrolytes occur from time to time. Although many studies have greatly improved the performance of t...

AI Technical Summary

Problems solved by technology

Nevertheless, the applicant believes that this invention is a lithium-ion-free and relies on Ag + The conductive solid electrolyte does not increase the diffusion channel of lithium ions by generating a large number of new atomic vacancies so as to achieve the effect of improving the lithium ion conductivity of the sulfide-based solid electrolyte; the silver ion conductive solid prepared by the method described in the invention The electrolyte is not suitable for use as a solid electrolyte between the positive and negative electrodes of an all-solid lithium battery because: Ag + Migration is not accompanied by electrochemical reactions and thus cannot become a battery. On the other hand, when charging and discharging, Ag + Migrating to a low-potential interface will form a barrier that hinders the passage of lithium ions, and cause a large amount of lithium ions to stay in the silver iodide solid electrolyte. The consumption of a large amount of lithium ions will make the coulombic efficiency of the battery's initial cycle very low, making it difficult to maintain charge and discharge cycles.

[0008] At present, there is no report about adding silver iodide and silver chloride to the lithium sulfide solid electrolyte material to improve its ion conductivity.