Preparation of lithium iron phosphate with superior electrochemical performances from titanium white by-product ferrous sulfate

In this paper, FePO4∙2H2O and FePO4 have been successfully accomplished by utilizing titanium white by-product ferrous sulfate via two-step synthesis method, which is further employed to react with Li2CO3 via carbothermal reduction to prepare LiFePO4 cathode materials. The composition and structure characteristics of obtained samples are studied in detail by TG-DSC, XRD, XPS, FESEM and TEM, and the electrochemical performances of prepared LiFePO4 are also carefully investigated. The results indicate that the discharge specific capacity of LiFePO4 synthesized from FePO4 achieves 162.4 and 153.7 mAh∙g−1 at 0.1C and 1C, which is 2.2 and 2.9 mAh∙g−1 higher than that from FePO4∙2H2O, and the capacity retention rate reaches as high as 97.5 % after 450 cycles at 1C, correspondingly 94.8 % for LiFePO4 from FePO4∙2H2O. It is mainly ascribed to the smaller particle size of LiFePO4 synthesized from FePO4, and the intimately ordered interface structure between the carbon layer and LiFePO4, which greatly promotes the migration of lithium ions in the lithiation and delithiation process. •Titanium white by-product ferrous sulfate has been utilized to synthesize LiFePO4.•The max discharge specific capacity of LiFePO4 achieves 162.4 mAh∙g−1 at 0.1C.•Smaller grain size and intimate interface structure lead to superior performances.