Bio-Inspired Site-Specific Atomic Repair for Energy-Efficient Regeneration of Spent LiFePO₄ Batteries.

Abstract

Solid-state sintering regeneration offers a promising strategy for repairing spent lithium iron phosphate (LFP) cathodes, yet conventional homogeneous-mixing (HM) sintering approaches neglect the intrinsic heterogeneity of FePO₄ within LFP particles. This induces additional long-range Li⁺ solid-state migration from Li-rich to Li-deficient domains during regeneration, creating substantial solid-state diffusion barriers that necessitate extended high-temperature sintering duration while triggering local over-lithiation, ultimately degrading regeneration performance. Inspired by specific antigen-antibody-phagocyte interactions, we propose a novel mechanistic concept of site-specific atomic repair (SAR) for energy-efficient LFP regeneration. Through targeted-adsorption-enhanced evaporation-nucleation processes, lithium sources and reductants are selectively anchored onto heterogeneous FePO₄ domains for localized repair, which shortens Li⁺ solid-state diffusion pathways, lowers migration barrier, and reduces FePO₄ → LiFePO₄ transition temperature from 300-400°C to 100-200°C. Consequently, the SAR-regenerated LFP cathodes deliver enhanced performance while requiring only half of the high-temperature sintering duration of conventional HM approaches, thereby achieving ∼20%-30% reduction in energy consumption & CO₂ emissions with a markedly improved profit by ∼40%. With additional heteroatom doping, SAR demonstrates exceptional rate performance (73.0 mAh g^-1 at 15 C) and long-term stability (90.0% after 600 cycles), ranking among the best reported to date, demonstrating cost-effective mechanistic advances for industrial-scale LFP recycling.