Improving the Electrochemical Performance of LiFePO4/C Cathode by Selection of Carbon Source

Abstract

LiFePO4/C composite was synthesized by an easy sol-gel method using FeC2O4•H2O as iron source, citric acid and ethylene glycol as carbon source. The results showed that citric acid was inclined to leave more carbon in the synthesized material than ethylene glycol was and the carbon content increased greatly with the increasing amount of citric acid. When ethylene glycol was applied as carbon source, it left only a few amount of carbon (1.6 wt%) in the material. By optimizing the addition of carbon source, LiFePO4/C particles with uniform carbon coating and a little carbon content was obtained. The LiFePO4/C composite synthesized with 1/1 ratio of ethylene glycol to cations demonstrated the best electrochemical performance with its capacity of 143 mAh/g at 0.1C and 110 mAh/g at 1C within the voltage range of 2.5-4.2V (vs. Li/Li+). The results will provide ideas for the improvement of overall properties of LiFePO4 material for its application in the field of electric vehicles.