Hybrid Surface Modification and Bulk Doping Enable Spent LiCoO₂ Cathodes for High‐Voltage Operation

Abstract The emerging market demand for high‐energy‐density of energy storage devices is pushing the disposal of end‐of‐life LiCoO₂ (LCO) to shift toward sustainable upgrading into structurally stable high‐voltage cathode materials. Herein, an integrated bulk and surface commodification strategy is proposed to render spent LCO (S‐LCO) to operate at high voltages, involving bulk Mn doping, near surface P gradient doping, and Li₃PO₄/CoP (LPO/CP) coating on the LCO surface to yield upcycled LCO (defined as MP‐LCO@LPO/CP). Benefiting from hybrid surface coating with Li⁺‐conductive Li₃PO₄ (LPO) and electron conductive CoP (CP) coupled with Mn and P co‐doping, the optimized MP‐LCO@LPO/CP cathode exhibits enhanced high‐voltage performance, delivering an initial discharge capacity of 218.8 mAh g⁻¹ at 0.2 C with excellent capacity retention of 80.9% (0.5 C) after 200 cycles at a cut‐off voltage of 4.6 V, along with 96.3% of capacity retention over 100 cycles at 4.5 V. These findings may afford meaningful construction for the upcycling of commercial S‐LCO into next‐generation upmarket cathode materials through the elaborate surface and bulk modification design.