Improved chemical stability and cyclability in Li2S–P2S5–P2O5–ZnO composite electrolytes for all-solid-state rechargeable lithium batteries

• Chemical stability in air of Li2S–P2S5–P2O5–ZnO composite electrolytes was examined.
• A partial substitution of P2O5 for P2S5 decreased the rate of H2S generation.
• The addition of ZnO to the glasses reduced the amount of H2S.
• All-solid-state lithium cells using the developed composite electrolytes exhibited good cyclability.

Sulfide glasses with high Li+ ion conductivity are promising solid electrolytes for all-solid-state rechargeable lithium batteries. This study specifically examined the chemical stability of Li2S–P2S5-based glass electrolytes in air. Partial substitution of P2O5 for P2S5 decreased the rate of H2S generation from glass exposed to air. The addition of ZnO to the Li2S–P2S5–P2O5 glasses as a H2S absorbent reduced the H2S gas release. A composite electrolyte prepared from 90 mol% of 75Li2S⋅21P2S5⋅4P2O5 (mol%) glass and 10 mol% ZnO was applied to all-solid-state cells. The all-solid-state In/LiCoO2 cell with the composite electrolyte showed good cyclability as a lithium secondary battery.