Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (05): 1183-1188.doi: 10.3866/PKU.WHXB201202221

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

Synthesis of LiFePO4 Cathode Materials by Mechanical-Activation-Assisted Polyol Processing

CAO Yan-Bing1,2, DUAN Jian-Guo1, JIANG Feng2, HU Guo-Rong1, PENG Zhong-Dong1, DU Ke1   

  1. 1. School of Metallurgical Science and Engineering, Central South University, Changsha 410083, P. R. China;
    2. School of Materials Science and Engineering, Central South University, Changsha 410083, P. R. China
  • Received:2011-11-02 Revised:2012-02-04 Published:2012-04-26
  • Contact: CAO Yan-Bing
  • Supported by:

    The project was supported by the National Key Technology Research and Development Program of China (2007BAE12B01) and Technology Research and Development Program of Hunan Province, China (2009GK3150).

Abstract: A low-temperature approach for efficient preparation of LiFePO4 was developed. The rod-shaped [Fe3(PO4)2·8H2O + Li3PO4] precursor was prepared, using a mechanochemical liquid-phase activation technique, from LiH2PO4 and reduction iron powder. Pure LiFePO4 was then synthesized in boiling tetra(ethylene glycol) (TEG) by polyol processing with the as-prepared precursor. In order to improve the electrical conductivity, carbon coating of the pure LiFePO4 was carried out, using poly(vinyl alcohol) (PVA) as the carbon source. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), galvanostatic charge-discharge test and electrochemical impedance spectroscopy (EIS). The results show that well-crystallized LiFePO4 was successfully synthesized by polyol processing at low temperature. Carbon coating significantly improves the conductive properties of LiFePO4 and reduces charge-transfer impedance. The obtained LiFePO4/C composite delivers specific discharge capacities of 139.8 and 129.5 mAh·g-1 at 1C and 2C rates, respectively, displaying good cycling performance and rate capability.

Key words: Cathode Material, LiFePO4, Mechanical activation, Polyol processing, Carbon coating


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