Synthesis of LiFePO_4 using FeSO_4·7H_2O byproduct from TiO_2 production as raw material

摘要

As the byproduct of TiO2 industrial production, impure FeSO4·7H2O was used for the synthesis of LiFePO4. With the purified solution of FeSO4·7H2O, FePO4·xH2O was prepared by a normal titration method and a controlled crystallization method, respectively. Then LiFePO4 materials were synthesized by calcining the mixture of FePO4·xH2O, Li2CO3, and glucose at 700°C for 10 h in flowing Ar. The results indicate that the elimination of FeSO4·7H2O impurities reached over 95%, and using FePO4·xH2O prepared by the controlled crystallization method, the obtained LiFePO4 material has fine and sphere-like particles. The material delivers a higher initial discharge specific capacity of 149 mAh·g-1 at a current density of 0.1C rate (1C=170 mA·g-1); the discharge specific capacity also maintains above 120 mAh·g1 after 100 cycles even at 2C rate. Thus, the employed processing is promising for easy control, low cost of raw material, and high electrochemical performance of the prepared material.