Efficient Direct Regeneration of Spent LiFePO4 Cathodes via Molecular Fencing and Vapor Deposition

Abstract Direct regeneration is recognized as the most promising strategy for recycling spent LiFePO 4 (SLFP) due to its economic and environmental advantages. However, challenges persist in high‐temperature solid‐phase regeneration, including uneven lithium compensation from particle agglomeration and conflicting timing between lithiation and carbon coating. Therefore, a regeneration strategy is proposed utilizing a molecular fence and vapor deposition mechanism. Lithiation, vapor‐deposited carbon coating, and in situ nitrogen doping are achieved through the synergistic effect of creatine and lithium stearate. Lithium stearate forms a molecular fence on SLFP surfaces, enhancing particle dispersion and uniform lithium replenishment. Below 300 °C, NH 3 released from creatine decomposition drives Li + insertion into the SLFP lattice to reduce Fe 3+ , completing lithiation. Subsequently, the generated small carbon‐nitrogen molecules radicals undergo structural reorganization, forming a continuous conjugated structure that forms an in situ nitrogen‐doped 3D conductive carbon network with topological defects. The heterocyclic and defective structures in the carbon coating modulate electron cloud distribution, creating additional active sites for electron transport and significantly improving conductivity. The regenerated LiFePO 4 delivers a discharge capacity of 146.2 mAh g −1 at 1 C and retains 95.83% capacity after 200 cycles. This strategy offers a viable pathway for high‐efficiency, high‐quality SLFP recycling.