A unique co-recovery strategy of cathode and anode from spent LiFePO4 battery

Along with the explosive growth in the market of new energy electric vehicles, the demand for Li-ion batteries (LIBs) has correspondingly expanded. Given the limited life of LIBs, numbers of spent LIBs are bound to be produced. Because of the severe threats and challenges of spent LIBs to the environment, resources, and global sustainable development, the recycling and reuse of spent LIBs have become urgent. Herein, we propose a novel green and efficient direct recycling method, which realizes the concurrent reuse of LiFePO4 (LFP) cathode and graphite anode from spent LFP batteries. By optimizing the proportion of LFP and graphite, a hybrid LFP/graphite (LFPG) cathode was designed for a new type of dualion battery (DIB) that can achieve co-participation in the storage of both anions and cations. The hybrid LFPG cathode combines the excellent stability of LFP and the high conductivity of graphite to exhibit an extraordinary electrochemical performance. The best compound, i.e., LFP:graphite = 3:1, with the highest reversible capacity (∼130 mA h g−1 at 25 mA g−1), high voltage platform of 4.95 V, and outstanding cycle performance, was achieved. The specific diffusion behavior of Li+ and PF6− in the hybrid cathode was studied using electrode kinetic tests, further clarifying the working mechanism of DIBs. This study provides a new strategy toward the large-scale recycling of positive and negative electrodes of spent LIBs and establishes a precedent for designing new hybrid cathode materials for DIBs with superior performance using spent LIBs.