Upcycling of Degraded LiCoO₂ Cathodes into High‐Performance Lithium‐Ion Batteries via a Three‐In‐One Strategy

Abstract Faced with the forthcoming tide of retired lithium‐ion batteries (LIBs), it is imperative to explore effective regeneration and upcycling strategies to alleviate the resource shortage, address environmental pollution, and cater to the demand for high‐energy‐density cathode materials. Herein, a facile, non‐constructive, one‐stone‐for‐three‐birds solid‐phase sintering strategy is proposed to regenerate the degraded LiCoO₂ (D‐LCO) cathode and even upgrade its stability at high voltages, in which three birds, i.e., lithium supplement, Li₂SO₄ coating, and Mn doping into Co sites while N, S doping into Li‐O slabs are simultaneously hit with one stone (one‐pot solid‐phase sintering). Benefiting from these favorable characteristics, the upcycled cathode not only yields high discharge‐specific capacity of 188.2 mAh g⁻¹ at 0.2 C, but also delivers superior cycling performance with 92.5% of capacity retention after 100 cycles (86.4% after 300 cycles) at 0.5 C and excellent rate capability at a high cutoff voltage of 4.5 V, superior to a freshly commercial counterpart. This work is expected to provide meaningful guidance for the upcycling of D‐LCO into high‐energy‐density batteries with long‐term cycling stability.