Direct Recycling Strategy for Spent Lithium Iron Phosphate Powder: an Efficient and Wastewater-Free Process

Due to its high safety and long cyclic life, the LiFePO4 (LFP) battery has received numerous attention and has been widely used in electric vehicles. Therefore, it is urgent to develop advanced technology to recycle spent LFP batteries to avoid energy exhaustion and protect the environment. Here, we report a direct regeneration strategy for spent LFP powder based on the wet full-component leaching method and traditional LFP production process. Specifically, combined leaching of spent LFP powder using H3PO4 and citric acid was done; meanwhile, the leaching solution is used as the precursor to regenerate LFP cathode materials by a typical LFP spray-drying process. The recovery rates of Li, Fe, and P were above 95%. Effective separation of Al elements could be realized by pretreatment of LFP with a low concentration of LiOH solution, and the Al removal rate can reach 89%. The LFP material regenerated through prealuminum removal demonstrated excellent electrochemical properties, with a discharge capacity of 123.3 mA h g-1 at a rate of 5 C. After 600 cycles at 1 C, its capacity retention was found to be as high as 97.3%. Moreover, the economic benefit analysis indicates that the progress is rewarding. This novel and simple method has made a breakthrough in the limitations of traditional LFP-recovery process, eliminating the complicated chemical precipitation process. Meanwhile, it realizes the direct recovery of LFP and eliminates wastewater at the origin, which is expected to be widely used in industry.