Inorganic sulfide solid electrolytes for all-solid-state lithium secondary batteries

Abstract

Liquid organic electrolytes are mostly used in commercial lithium-ion batteries, due to their advantages of high conductivity and excellent wetting of the electrode interface. However, liquid organic electrolytes are flammable and volatile, causing safety issues of commercial lithium-ion batteries in electric vehicles. Recently, all-solid-state lithium secondary batteries have attracted great attention owing to their high safety and increased energy density, and are considered the most promising next generation energy storage systems. The most essential components are solid electrolytes for all-solid-state lithium batteries. Among various inorganic solid electrolytes, sulfide solid electrolytes have received widespread attention because of their high ionic conductivity and good mechanical properties. Herein, we summarize the development of several typical sulfide solid electrolytes and the problems to be addressed in emerging all-solid-state lithium batteries. Finally, the future development directions of sulfide electrolytes and all-solid-state lithium batteries are briefly discussed.