Li₃InCl₆-coated LiCoO₂ for high-performance all solid-state batteries

Halide solid electrolytes (HSEs) could be coated on high-voltage oxide cathodes at molecular-level via a solution process, which is highly favorable for reducing the interface impedance. However, during the preparation of composite cathodes, hydrate intermediates of HSEs are easily hydrolyzed to produce inactive impurities. In this work, the vacuum drying assisted method facilitates the generation of pure Li3InCl6 (LIC) on the surface of LiCoO2 (LCO) to improve the electrolyte/electrode solid–solid interface as well as the electrochemical stability of solid electrolyte under high voltage. By introducing Li7P3S11 as an anode buffer layer, 30 wt. %-LIC-coated LCO demonstrates high specific capacity of 121.7 mAh g−1 and good cycling stability. Our study highlights a promising method to build advanced composite cathodes for all-solid-state batteries.