Direct regeneration of high-performance cathode materials from spent LCO batteries through in situ utilization of aluminum

With the impending increase in the number of retired lithium-ion batteries, effective recycling and upcycling strategies must be explored to alleviate resource shortages, address environmental pollution, and meet the growing demand for high-performance cathode materials. This study proposes a closed-loop upcycling strategy that utilizes current collector aluminum (Al) as both a dopant and raw material for surface coating. This approach repairs the structural defects of highly degraded LiCoO 2 (LCO) cathode materials and achieves bulk Al doping and surface LiAlO 2 coating, transforming them into high-performance cathode materials capable of stable operation at a high voltage of 4.5 V. Specifically, bulk Al doping suppresses irreversible phase transitions and enhances structural stability, while the LiAlO 2 coating improves interfacial charge transfer and mitigates polarization. The synergistic effects of these modifications collectively enhance the electrochemical stability of LCO. The upcycled material delivers an initial discharge capacity exceeding 181.5 mAh g -1 and retains 93.9% of its capacity after 200 cycles at 1 C. Even under a high current rate of 10 C, the discharge capacity remains above 150.1 mAh g -1 , thereby outperforming commercial LCO cathodes. This study provides a simple and efficient solution for the direct upcycling of degraded LCO cathode materials into high-performance alternatives.