Regeneration and performance of LiFePO4 with Li2CO3 and FePO4 as raw materials recovered from spent LiFePO4 batteries

The shortage of lithium resource has become a serious problem due to the ever-increasing demands for lithium-ions batteries (LIBs) in the fields of electric vehicle and grid energy storage. It is imperative to recycle LIBs whether from the perspective of value recovery or environmental protection. Herein, a new method for recovering FePO4 and Li2CO3 from spent LiFePO4 cathode materials is proposed. LiFePO4 was synthesized by carbothermal reduction based on the recovered FePO4 and Li2CO3. It is well known that LiFePO4 has poor electronic conductivity and ionic conductivity. In order to improve its electrochemical performance, accelerate the transport speed of lithium ions in the material, and improve its conductivity, a series of samples with different carbon coating contents are prepared. The physicochemical and electrochemical performances are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and electrochemical techniques. The results show that when the carbon is 12 wt% of the LiFePO4 composite total weight, the sample (LFP-G12) has better electrochemical performance. LFP-G12 has a high initial discharge specific capacity of 146.89 mAh g−1 at 1 C with 97.9% of the initial capacity was retained after 200 cycles. Thus, this paper offers a brand-new way for recycling and directly using the spent LiFePO4 to prepare LiFePO4 cathode material.