Interface-assisted in-situ growth of halide electrolytes eliminating interfacial challenges of all-inorganic solid-state batteries

All-inorganic solid-state batteries (AISSBs) have received considerable attention due to their excellent safety and high energy density. However, large interfacial challenges between oxide cathodes and inorganic solid electrolytes dramatically hinder AISSB development. Here we successfully eliminate the long-standing interfacial challenges by in-situ interfacial growth of a highly Li+-conductive halide electrolyte (Li3InCl6, LIC) on the cathode surface. Owing to strong interfacial interaction, high interfacial ionic conductivity (>1 mS cm−1), and excellent interfacial compatibility, LiCoO2 with 15 wt% LIC exhibits a high initial capacity of 131.7 mAh.g−1 at 0.1C (1C = 1.3 mA cm−2) and can be operated up to 4C at room temperature. The discharge capacity retains 90.3 mAh g−1 after 200 cycles. Moreover, a high areal capacity of 6 mAh cm−2 is demonstrated with a high loading of 48.7 mg cm−2. This work offers a versatile approach to eliminate interfacial challenges of AISSBs toward high-energy density and high-power density.