SYNTHESIS AND CHARACTERIZATION OF LiFePO4/C PREPARED VIA A SOL–GEL METHOD

Carbon-coated lithium ion phosphate was synthesized from a gel precursor with ferric iron and a carbon source of organic chelating agent via a sol–gel method. The dependence of the microstructure and electrochemical performance of the synthesized LiFePO 4 / C on the pH value of the precursor solution during gel formation and the sintering time was investigated. The obtained LiFePO 4 / C particles were characterized by X-ray diffraction, field-emission scanning electron microscopy, and element analysis. The results show that the pH value has little effect on the phase purity. At a sintering temperature of 700°C, the discharge capacity of LiFePO 4 / C under 0.1 C (1 C = 170 mA/g) regime decreased from 152.8 to 62.5 mAh/g with decreasing the sintering time from 12 h to 8 h. Appropriate sintering time can lead to well-crystallized LiFePO 4 / C , which improves the electrochemical performance.