Engineering Cathode-Electrolyte Interface of High-Voltage Spinel LiNi0.5Mn1.5O4 via Halide Solid-State Electrolyte Coating

Thehigh-voltage spinel LiNi0.5Mn1.5O4 (LNMO) cathode material with high energy density, low cost,and excellent rate capability has grabbed the attention of the field.However, a high-voltage platform at 4.7 V causes severe oxidativeside reactions when in contact with the organic electrolyte, leadingto poor electrochemical performance. Furthermore, the contact betweenthe liquid electrolyte and LNMO leads to Mn dissolution during cycles.In this work, we applied the sol-gel method to prepare Li3InCl6-coated LNMO (LIC@LNMO) to address the mentionedproblems of LNMO. By introducing a protective layer of halide-typesolid-state electrolyte on LNMO, we can prevent direct contact betweenLNMO and electrolyte while maintaining good ionic conductivity. Thus, we could demonstrate that 5 wt % LIC@LNMO exhibited a goodcycle performance with a Coulombic efficiency of 99% and a capacityretention of 80% after the 230th cycle at the 230th cycle at 1C atroom temperature.