Structural change of Li 2S–P 2S 5 sulfide solid electrolytes in the atmosphere

Abstract

The sulfides Li 2S−P 2S 5 are attractive solid electrolytes for all-solid-state lithium batteries since they have high lithium-ion conductivities and wide electrochemical windows. However, chemical stability of Li 2S-P 2S 5 solid electrolytes in the atmosphere is concerned. In the present study, the structure of Li 2S−P 2S 5 glasses and glass-ceramics after exposure to air was investigated for the first time. Raman spectroscopy demonstrated that the 75Li 2S∙25P 2S 5 (mol%) glass and glass-ceramic composed of Li + and PS 4 3− ions did not exhibit obvious structural changes on exposure to the atmosphere. The amount of H 2S generated from Li 2S−P 2S 5 glasses exposed to air depended on the glass composition. The composition of 75Li 2S∙25P 2S 5 generated the least amount of H 2S of Li 2S−P 2S 5 binary systems. 75Li 2S∙25P 2S 5 glass and glass-ceramic are promising solid electrolytes for all-solid-state lithium batteries in terms of chemical stability and conductivity.