Scalable Direct Recovery of Spent LiFePO4 with a Redox-Mediated Flow Cell

Abstract

The rapid increase in lithium-ion battery (LIB) usage has led to significant environmental challenges. Lithium loss is one of the most significant causes of capacity degradation in LIB. This study presents a novel redox-mediated electrochemical method for the direct recovery of spent LiFePO₄ (s-LFP) cathodes from spent LIBs. Using anthraquinone-2,7-disulfonic lithium salt (AQDS-Li) as the redox mediator (RM), the process operates in an aqueous flow system, minimizing chemical consumption and secondary pollution. The RM electrochemically generated on the electrode reduces s-LFP in a separate reactor tank and restores lithium content in the material, making it suitable for reuse. The restored LFP showed stable electrochemical behavior, good rate performance across various current densities, and excellent cycling stability. This method offers a cost-effective, environmentally friendly and scalable solution for LIB recycling, significantly reducing the environmental footprint and promoting the efficient use of critical resources.