Air-stable Li₃InCl₆ electrolyte with high voltage compatibility for all-solid-state batteries

Most inorganic solid-state electrolytes (SSEs) suffer from incompatibility with oxide cathode materials and instability in ambient air, presenting major barriers for their application in high performance all-solid-state batteries (ASSLBs). Herein, we report a rationally designed halide-based Li3InCl6 SSE with a high ionic conductivity of 1.49 × 10−3 S cm−1 (25 °C). The Li3InCl6 SSE is stable towards oxide cathode materials (e.g., LiCoO2) without any interfacial treatment. By applying the Li3InCl6 SSEs, significantly enhanced electrochemical performances are achieved in terms of capacity and durability. Experimental investigations reveal that the Li3InCl6 can avoid side reactions between the SSEs and the oxide cathode materials and thus effectively improve the Li+ migration across the interface. Moreover, Li3InCl6 is highly stable in ambient air and possesses good ionic conductivity retention after a reheating process, further making it an attractive electrolyte for next-generation ASSLBs.