Summary：

This invention provides a selenide-containing electrolyte and a lithium-sulfur battery, involving a method of generating high-reactivity S-Se bonds to improve the kinetics of the sulfur cathode and forming rich selenide-containing solid electrolyte interphase (SEI) to protect the lithium metal. The method significantly enhances the kinetics of sulfurized polyacrylonitrile by incorporating specific types of inorganic selenide additives into the electrolyte of lithium-sulfur batteries, facilitating the formation of highly electrochemically active S-Se bonds during discharge-charge processes. The cycle and rate capabilities are significantly enhanced in the ether-based electrolyte, while the incorporation of inorganic selenide promotes uniform lithium deposition and suppresses the growth of dendritic, thereby safeguarding lithium metal. This invention effectively improves sulfur kinetics and provides cost-efficient protection for lithium metal.