Organic-inorganic multi-scale enhanced interfacial engineering of sulfide solid electrolyte in Li-S battery

Abstract

The developing sulfide solid electrolyte is a promising way to overcome shuttle effect of polysulfide in the traditional liquid Li-S battery. However, an air stable sulfide solid electrolyte and competitive solid–solid interface structure must be constructed firstly. Herein, we have designed an organic–inorganic multi-scale composite electrolytes to overcome the interfacial issues of solid state Li-S batteries (SSLSBs). The organic–inorganic composite electrolyte consists of a gel polymer electrolyte (GPE) and an oxygen doped inorganic sulfide solid electrolyte. The O doped sulfide solid electrolyte improves its chemical stability and suppresses the lithium dendrites. A thin GPE film protects the crystal structural stability during cycles and greatly enhances the performance of O doped sulfide solid electrolyte due to the GPE not only constructs soft interface contact between S cathode and solid electrolyte, but also builds lithium ion transport paths by ionic liquid between them. Those SSLSBs display a very good cycling performance with the specific capacity of 1023 mAh/g after 50 cycles at 60 °C and 541 mAh/g after 150 cycles at 30 °C under same rate of 0.1 C. This study demonstrates that the development of advanced solid-state Li-S battery needs to fully integrate a number of technical advantages.