A LiFePO4 regeneration method based on PVAc alcoholysis reaction

Regeneration of LiFePO4 from spent LiFePO4 cathode material has been proposed by using a new carbon source in the mixture system of methanol and ammonia water. Adding appropriate Li2CO3, FeC2O4, and NH4H2PO4, the spent LiFePO4 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, Xray 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 LiFePO4 batteries to a certain extent. The optimum amount of PVAc still needs further study. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

A new method for regenerating spent LiFePO4 cathode material using a new carbon source was proposed, achieving high-performance regenerated samples. The addition of different amounts of PVAc in the mixture system significantly reduced the addition of carbon sources, leading to improved morphology, structure, and electrochemical performance of the regenerated samples.