From waste to material strategy: A closed-loop regeneration process of spent LiFePO4 batteries

A closed-loop regeneration route to recover valuable elements from spent LiFePO4 batteries is proposed. After hot-acid leaching, the leaching rates of Li, Fe and P are above 99.8 %, and the graphite powder retain in the residue with grade of 93.33 %. With iron powder cementation, 99.96 % Cu is removed from acid leaching solution to obtain sponge copper. And then 96.67 %Al and 89.30 %F are precipitated in the form of AlPO4(s) and FeF3(s) at pH = 3.75. Li, Fe and P within the purified solution are prepared as LiFePO4 precursors by coprecipitation method, and finally LiFePO4/C materials are synthesized after two-stage calcination. The recycled LiFePO4/C materials demonstrate excellent electrochemical performance with a discharge capacity of 153.1 mAh & sdot;g- 1 at 0.1C and a capacity retention of 94.0 % after 500 cycles at 1C. The present recycling process provides a strategy for short and efficient regeneration of spent LiFePO4 batteries.