Vanadium-Doping Induced Direct Regeneration of Spent LiFePO 4 toward Ultra-Stable Cathode Materials with High Rate Performance

The direct regeneration method restores the cathode material in spent LFP batteries, achieving resource recovery from “waste materials” while preventing pollution generation. However, how to achieve long-term cycling performance of regenerated LFP materials at high rates is a problem. Herein, we report an effective direct regeneration strategy by using of the vanadium(V) doping to repair waste LFP (R-LFP@V) characterized by outstanding cycling performance at large current density. Doping with V effectively reduces the grain size and unit cell volume of recycled LFP, thereby shortening the paths that lithium ions must travel within the crystal and further enhancing their diffusion rates. Consequently, the regenerated LFP material exhibits the well-defined microstructure and excellent electrochemical performance. The lithium-ion battery with R-LFP@V displays a high discharge capacity of 159.38 mAh g–1 at 0.05 C (capacity recovery >97.6%). In particular, this kind of battery shows the impressive capacity retention rate of 84.21% after 1000 cycles at much high rate of 10 C. The V-doped solid-state regeneration technique proposed in our work offers great advantages of simplicity, environmental friendliness and high efficiency. Not only does it enhance the material’s electronic conductivity and lithium-ion diffusion rate, it also holds significant potential for use in recycling waste lithium iron phosphate materials.