Structural reinforcement and nucleation regulation via Fe vacancy engineering for high-performance regenerated LiFePO4 cathodes

The widespread utilization of LiFePO 4 (LFP) batteries has rendered the green regeneration of spent LFP cathode materials (SLFP) an urgent priority. Selective lithium extraction strategies have rapidly advanced through enabling simplified yet efficient lithium recycling. However, under acidic conditions, minor Fe dissolution was observed to significantly reduce the structural stability of regenerated LFP materials while exacerbating Li/Fe antisite defects. A novel strategy based on Fe vacancy site-mediated bond energy reinforcement and nucleation regulation was proposed to achieve structural reinforcement and high-efficiency regeneration. Experimental characterization revealed that Li/Fe antisite defects in regenerated materials were reduced from 1.48 % to 0.93 %, with grain size being significantly refined. The regenerated material exhibited a reversible capacity of 150.2 mAh·g −1 at 1C rate, maintaining 94.74 % capacity retention after 500 cycles, while its discharge capacity at 5C rate was elevated by 60 mAh·g −1 . Environmental and economic assessments conducted via the everbatt model demonstrated significant advantages of this strategy.