Lithium sulfide solid electrolyte material of silver-containing halogen compound composite powder and preparation method thereof

Abstract

The invention discloses a lithium sulfide solid electrolyte material of silver-containing halogen compound composite powder and a preparation method thereof. The preparation method comprises the steps of 1) weighing 35-50% lithium sulfide and the balance of phosphorus sulfide according to weight percentage under the condition of atmosphere protection, and mixing the lithium sulfide and the phosphorus sulfide uniformly to obtain a lithium-sulfur-phosphorus ternary mixture; 2) taking the lithium-sulfur-phosphorus ternary mixture, silver iodide which accounts for 2-6% by weight of the lithium-sulfur-phosphorus ternary mixture, silver bromide which accounts for 1-3% by weight of the lithium-sulfur-phosphorus ternary mixture and silver chloride which accounts for 1-3% by weight of the lithium-sulfur-phosphorus ternary mixture, putting the taken materials in a ball milling pot to obtain an amorphous lithium-sulfur-phosphorus mixture containing silver iodide, silver bromide and silver chloride; and 3) sealing the amorphous lithium-sulfur-phosphorus mixture containing silver iodide, silver bromide and silver chloride under the condition of atmosphere protection and red light, and then heating the mixture to 60-180 DEG C under a vacuum or atmosphere protection condition for heat treatment so as to obtain the lithium sulfide solid electrolyte material of the silver-containing halogen compound composite powder.

Description

technical field [0001] The invention relates to a lithium sulfide-based solid electrolyte material, in particular to a lithium sulfide-based solid electrolyte material containing silver-halogen compound composite powder 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 t...

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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 simultaneous addition of silver iodide, silver bromide and silver chloride to lithium sulfide solid electrolyte materials to improve their ion conductivity.