Lithium sulfide solid electrolyte material containing silver iodide and silver bromide and preparation method of lithium sulfide solid electrolyte material

Abstract

The invention discloses a lithium sulfide solid electrolyte material containing silver iodide and silver bromide and a preparation method of the lithium sulfide solid electrolyte material. The preparation method comprises the following steps of (1) weighing 35%-50% of lithium sulfide and the balance of phosphorus sulfide according to mass percents under the condition of atmosphere protection and mixing evenly to obtain a lithium-sulfur-phosphorus ternary mixture; (2) taking the lithium-sulfur-phosphorus ternary mixture, the silver iodide which is equivalent to 2%-6% of the mass of the lithium-sulfur-phosphorus ternary mixture and the silver bromide which is equivalent to 1%-5% of the mass of the lithium-sulfur-phosphorus ternary mixture under the conditions of atmosphere protection and safe red light and carrying out ball-milling to obtain an amorphous lithium-sulfur-phosphorus mixture containing the silver iodide and the silver bromide; and (3) sealing the obtained amorphous lithium-sulfur-phosphorus mixture containing the silver iodide and the silver bromide under the conditions of atmosphere protection and red light, and heating the amorphous lithium-sulfur-phosphorus mixture to 100-200 DEG C under a vacuum condition or the condition of atmosphere protection for thermal treatment. According to the method disclosed by the invention, the ion conductivity of the obtained lithium sulfide solid electrolyte material can be effectively improved.

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 bromide 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 tr...

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 on the addition of silver iodide and silver bromide to lithium sulfide solid electrolyte materials to improve their ion conductivity.