Recycling Spent LiCoO₂ for Improved 4.6 V Performance

Rapid replacement of “3C” (computer, communication, and consumer electronics) products and the limited calendar life of batteries lead to the increasing retirement of LiCoO2 (LCO)-based lithium-ion batteries (LIBs), which makes recycling in high demand for a sustainable development. Herein, we propose a straightforward sintering process to rejuvenate the spent LCO to achieve a much-favored cycling stability at 4.6 V. The addition of Mg3(PO4)2 is critical for restoring the structure of spent LCO after heat treatment, enabling a synergistic effect of bulk Mg2+ doping and surface Li3PO4 decoration in the reconstructed LCO. This structural modification effectively suppresses harmful O3/H1–3 phase transitions and enhances Li+ transport dynamics, thereby endowing the recycled LCO with extraordinary cycling stability and rate performance. In the 4.5 V LCO/graphite pouch cell, a capacity retention of 75% is achieved after 480 cycles. Our work provides an efficient route for recycling and reusing spent LCO cathode materials, showing promise for practical applications.