Regeneration strategy inducing (010) facet exposure for enhanced Li+ transport in spent LiFePO4

The continuous accumulation of spent LiFePO 4 cathodes underscores the urgent need to develop sustainable and economically viable recycling technologies. An efficient solid-state regeneration strategy is established to realize lithium replenishment and defect reconstruction by a simple process to reduce spent LiFePO 4 only through thermal decomposition of L-cysteine. Acting concurrently as a reductant, carbon precursor, and N/S dopant, L-cysteine facilitates lattice reconstruction while forming a uniform N/S co-doped carbon coating that enhances the cathode electronic conductivity. DFT calculations further reveal that the regeneration process preferentially stabilizes the (010) facet by significantly reducing its surface energy, thereby exposing a low-energy Li + -conducting plane that accelerates ion migration. The regenerated LiFePO 4 demonstrates a high discharge capacity up to 137.78 mAh g −1 even at 1C and maintains 121.5 mAh g −1 after 500 cycles, corresponding to an excellent capacity retention of 86%. This work offers a feasible and economically competitive strategy to regenerate LiFePO 4 not only with N/S co-doped carbon coating, but also with (010) exposure facet, which impart directly regenerated LiFePO 4 with enhanced electronic conductivity and accelerated ion transport to exhibit excellent lithium-storage performances.