High performance Li2S–P2S5 solid electrolyte induced by selenide

•Nonhygroscopic and chemically stable selenide is introduced into Li2S–P2S5.•A high ionic conductivity 1.5 × 10−3 S cm−1 at room temperature is achieved.•The obtained solid electrolyte has a wide electrochemical window over 6.5 V.•Double substitution effect results in the high lithium ion conductivity.

Nonhygroscopic selenide of Ge0.35Ga0.05Se0.60 was introduced into the Li2S–P2S5 system by partially substituting P2S5 to form a new lithium ion solid electrolyte. And the electrochemical property of the as-prepared solid electrolyte was systematically studied. The optimal sample achieved a wide electrochemical window over 6.5 V and fairly high Li-ion conductivity of 1.5 × 10−3 S cm−1 at ambient temperature. And it is also verified that the studied electrolyte was much stable when contacts with lithium metal at 100 °C for 4 h. This new finding may provide an electrolyte material for developing all-solid-state lithium batteries.