An amorphous superionic conductor Li3PS4-xLiBr with high conductivity and good air stability by halogen incorporation

An amorphous superionic conductor is a promising solid electrolyte (SE) with excellent ionic conductivity and high energy density, which would be promising candidates for all-solid-state lithium-ion batteries. However, these advantageous features alone are difficult to achieve large-scale practical applications. Having a simple, effective synthetic route and good air stability is also critically important for SEs. Here, Li 3 PS 4 – x LiBr glass SE with high conductivity was obtained by simple mechanical milling and subsequent short-term low-temperature treatment. The site disorder between S 2− and Br − anions facilitates ionic transport. Our comparison of air stability before and after doping with halogen revealed that Br − doping well reduced the production of H 2 S gas and improved the air stability of the SE.