Coating Robust Layers on Ni-Rich Cathode Active Materials while Suppressing Cation Mixing for All-Solid-State Lithium-Ion Batteries

This study focused on addressing the challenges associated with the incompatibility between sulfide solid electrolytes and Ni-rich cathode active materials (CAMs) in all-solid-state lithium-ion batteries. To resolve these issues, protective layers have been explored for Ni-rich materials. Lithium lanthanum titanate (LLTO), a perovskite-type material, is recognized for its excellent chemical stability and ionic conductivity, which render it a potential protective layer in CAMs. However, traditional methods of achieving the perovskite structure involve temperatures exceeding 700 °C, resulting in challenges such as LLTO agglomeration, secondary phase formation between LLTO and CAM, and cation mixing within the CAM. In this study, a rapid technique known as flash-light sintering (FLS) was employed to fabricate a uniform and pure perovskite protective layer without inducing cation mixing within the CAM. The LLTO-coated LiNi