LiFePO4/C with high capacity synthesized by carbothermal reduction method

Abstract

The olivine-type LiFePO4/C cathode materials were prepared via carbothermal reduction method using cheap Fe2O3 as raw material and different contents of glucose as the reducing agent and carbon source. Their structural and morphological properties were investigated by X-ray diffraction, scanning electron microscope, transmission electron microscope, and particle size distribution analysis. The results demonstrated that when the content of the carbon precursor of glucose was 16 wt.%, the synthesized powder had good crystalline and exhibited homogeneous and narrow particle size distribution. Even and thin coating carbon film was formed on the surface of LiFePO4 particles during the pyrolysis of glucose, resulting in the enhancement of the electronic conductivity. Electrochemical tests showed that the discharge capacity first increased and then decreased with the increase of glucose content. The optimal sample synthesized using 16 wt.% glucose as carbon source exhibited the highest discharge capacity of 142 mAh g−1 at 0.1C rate with the capacity retention rate of 90.4% and 118 mAh g−1 at 0.5C rate.