A LiFePO4 regeneration method based on PVAc alcoholysis reaction

Regeneration of LiFePO 4 from spent LiFePO 4 cathode material has been proposed by using a new carbon source in the mixture system of methanol and ammonia water. Adding appropriate Li 2 CO 3 , FeC 2 O 4 , and NH 4 H 2 PO 4 , the spent LiFePO 4 materials were regenerated through high-temperature solid-state reaction with the different amounts of PVAc. Compared with traditional regeneration methods, the addition of carbon sources was greatly reduced in this work. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), Raman spectra, X-ray photoelectron spectroscopy (XPS), and electrochemical measurement. According to these results, the regenerated sample with 2.5 wt% PVAc displayed the best morphology, structure, and electrochemical performance. It delivered a high initial capacity of 163.2 mA h g −1 at the rate of 0.1 C, and a high capacity retention of 97.08% at a rate of 0.5 C after 100 cycles, which could meet the commercial requirements of regenerated LiFePO 4 batteries to a certain extent. The optimum amount of PVAc still needs further study. • Polyvinyl acetate is used to regenerate spent LiFePO4. • The preferred addition amount of polyvinyl acetate is 2.5 wt%. • Polyvinyl alcohol is released from alcoholysis of polyvinyl acetate. • The precursor is mixed and stirred in methanol and ammonia water.