A novel process to recycle spent LiFePO4 for synthesizing LiFePO4/C hierarchical microflowers

A novel process has been demonstrated to recycle LiFePO4 from spent lithium-ion batteries. The spent LiFePO4 cathode materials were leached by phosphoric acid (H3PO4) solution and followed by subsequent heat treatment to obtain FePO4 center dot 2H(2)O hierarchical microflowers. Furthermore, new LiFePO4/C sample was prepared via a carbothermal reduction process of calcining the obtained FePO4 center dot 2H(2)O precursor with Li2CO3 and glucose in N-2 atmosphere. The re-synthesized LiFePO4/C sample inherits the hierarchical microflower structure of the FePO4 center dot 2H(2)O precursor, with a diameter of 1-2 mu m. Electrochemical test indicates that the re-synthesized LiFePO4/C shows excellent electrochemical performance as cathode material for lithium ion batteries. The discharge capacity can reach 159.3 mAh g(-1) at 0.1C rate and 86.3 mAh g(-1) even at 20C rate, respectively. After 500 cycles at 5C, they still can deliver a discharge capacity of 105 mAh g(-1) with a high capacity retention rate of 95.4%. Moreover, the lithium element was also recovered in the form of LiH2PO4 from the filtrate after collecting the FePO4 center dot 2H(2)O precipitate. This work provides a promising route for large scale recovery and reuse of spent LiFePO4 cathode materials of lithium-ion batteries. (C) 2015 Elsevier Ltd. All rights reserved.