Summary:

The present invention belongs to the field of secondary batteries, and more specifically, relates to a solid phase conversion mechanism sulphur cathode, its preparation and application. The present invention obtains a sulphur cathode active substance by mixing a sulphur-selenium complex with a porous carbon material by ball milling and then heat treating, and then the active substance is mixed with a conductive agent and a binder to make a slurry, which is prepared by coating a collector to obtain a sulphur cathode, and this sulphur cathode material is prepared in a simple way; it is matched with a suitable electrolyte, and assembled into a lithium-sulphur battery. Through the reaction between the intermediate product polysulfide and the electrolyte additives and the optimization of the electrolyte solvation structure, the SEI film is rapidly formed in situ on the surface of the sulfur cathode during the initial cycling process, and the reaction mechanism of the sulfur cathode is converted from a dissolution-deposition mechanism to a quasi-solid phase conversion, which can avoid the problem of the dissolution-diffusion of the polysulfide completely, and improve the long-cycle performance of the lithium-sulfur battery.

Link: http://epub.cnipa.gov.cn/patent/CN115732668A