Scalable Top‐Down Approach for Recycling Highly Degraded Spent LiFePO₄ via Lattice Fragmentation‐Regeneration

Abstract Designing efficient, scalable, and eco‐friendly recycling technologies is crucial for addressing the widespread decommissioning of spent lithium‐ion batteries. Here, an innovative top‐down regeneration method is introduced to rejuvenate highly degraded LiFePO₄. Initially, the crystal structure of spent LiFePO₄ is destroyed via the oxidation process, followed by the reconstruction of the LiFePO₄ lattice through the reduction process. The regenerated LiFePO₄ features a uniform particle size and an intact crystal lattice, leading to substantial improvements in electrochemical performance. Specifically, it achieves a capacity of 142.6 mAh g⁻¹ at 1 C, significantly surpassing the spent LiFePO₄ (only 55.6 mAh g⁻¹ at 1 C). Furthermore, it demonstrates an exceptional retention of 86.7% after 450 cycles, in contrast to 55.8% retention of commercial LiFePO₄. More importantly, spent LiFePO₄ with varying degrees of degradation is successfully regenerated using this technology, confirming its scalability. Therefore, this research highlights a transformative and sustainable approach to LiFePO₄ regeneration, achieving splendid advancements in both electrochemical performance and cycle stability, and offers a novel pathway for the effective recycling of LiFePO₄‐based energy storage systems.