Enhanced all-solid-state battery performance through in-situ construction of interface modification layer

The development of high-performance all-solid-state lithium batteries (ASSLBs) relies on improving the interface stability between layered oxide cathodes and sulfide electrolytes, as well as the structural stability of cathode active materials. While coating technology is considered an effective solution, the fabrication of these coating materials using economically viable and scalable manufacturing processes remains a comprehensive and challenging task. In this study, a combination of first-principles calculations and experiments is employed to propose, for the first time, a simple and scalable aqueous process to in-situ construct an Li3VO4 (LVO) buffer coating on the surface of LiCoO2(LCO) cathode, which exhibits high ionic conductivity, relatively low electronic conductivity, and high oxidation limit. The LVO buffering coating not only facilitates the migration of lithium ions at the interface, effectively suppresses interface side reactions, and reduces interface impedance, but also enhances the mechanical and structural stability of the cathode material. As a result, the LCO/LPSC/Li-In ASSLBs with 2% LVO coating exhibit an initial discharge capacity of up to 145.6 mAh g−1 at room temperature (0.1C), with a capacity retention of 94.89% after 100 cycles. Furthermore, the ASSLBs demonstrate good capacity and cycle stability under extreme testing conditions, including high voltage, high temperature, and low temperature, especially exhibiting an initial discharge capacity of up to 114.9 mAh g−1 at −20 °C.