Lithium Superionic Conductor-Assisted Regeneration of Spent LiFePO ₄ Cathodes for Enhanced Kinetic Performance

Currently, the number of retired electric vehicles is growing rapidly, which poses a significant challenge to recycle spent batteries in a green manner. Herein, we propose a lithium superionic conductor-assisted solid-phase sintering for direct lithium iron phosphate (LFP) regeneration, aiming to simultaneously restore capacity and improve kinetic properties. Lithium aluminum titanium phosphate couples with LFP via doping and compositing, thus elevating the Li-ionic conductivity to 2.14 × 10–4 S·cm–1. Furthermore, the regenerated material undergoes a solid solution reaction at a high-lithium content (Li0.9FePO4) during cycling, which further enhances the kinetic performance. The regenerated LFP achieves a discharge capacity of 149.4 mAh·g–1 at 1C with a capacity retention of 89% after 800 cycles and a rate capacity of 100.4 mAh·g–1 at 10C. Besides, the regenerated LFP exhibits enhanced performance in all-solid-state batteries. This work offers a pathway for the direct regeneration of LFP cathodes from spent lithium-ion batteries.