Closed‐Loop Regenerative Cycling of Spent LiFePO 4 Cathodes via Integrated Lattice Reconstruction and Hydrometallurgy

Abstract Given the environmental and economic value of LiFePO 4 (LFP), methods for the regeneration of spent LFP have garnered significant attention. Owing to the uniform physicochemical properties of regenerated samples, regeneration involving lattice reconstruction is considered a next‐generation recycling technology. However, existing studies have focused only on initially retired materials and not secondary or tertiary retired materials. Therefore, this study proposes full‐lifecycle‐tiered recovery approaches to facilitate sustainable multicycle regeneration. The accumulation of Li─Fe antisite defects and development of non‐uniform C coatings result in diminished energy storing performance in secondary or tertiary regenerated materials. Herein, an improved mechanism for Li‐ion diffusion is developed using density functional theory (DFT) calculations, revealing that a suitable ratio of Li─Fe antisite defects can enhance Li‐ion diffusion in surrounding channels. However, C layer degradation from a uniform to non‐uniform state is attributed to the deterioration of the precursor surface and adsorption capacity. Considering these findings, secondary and tertiary regenerated materials are herein deemed suitable for further recovery via elemental extraction. Moreover, a QR code recognition system is proposed for monitoring battery information. Overall, this study provides insight into the physicochemical devolution of multi‐regenerated LFP and introduces full‐lifecycle tiered recovery approaches for spent LFP.