Co-recycling of spent cathode and anode via redox-mediated lithiation

Abstract

Direct recycling offers an optimal approach for the disposal of retired electrodes through non-destructive lithiation, enabling the efficient, cost-effective reuse of spent electrode materials. Typically, replenishing Li is crucial to address the vacant Li defects in spent cathodes for regeneration, while removing residual lithium is essential for the effective regeneration of spent anodes. Herein, given the high reactivity of residual lithium in the spent graphite with water, an innovative recycling strategy is proposed to achieve the direct separation and regeneration of spent cathode and anode materials through redox-mediated lithiation. The enhanced reductive capacity of the redox mediator in the Li-rich alkaline solutions enables its direct utilization for the re-lithiation of spent LiFePO₄ cathodes. On this basis, the Li ions released from the detached graphite on the Cu foil are reintroduced into the LiFePO₄ separated from the Al foil within a weakly alkaline environment. The regenerated LiFePO₄ exhibits improved electrochemical performance with a capacity of 142.4 mA h g⁻¹ at 1 C and a high retention of 95% after 1000 cycles at 5 C, while also outperforming conventional leaching methods in terms of economic and environmental benefits.