Journal of Inorganic Materials ›› 2012, Vol. 27 ›› Issue (4): 422-426.DOI: 10.3724/SP.J.1077.2012.00422

• Orginal Article • Previous Articles     Next Articles

Synthesis of Nano FePO4 and Electrochemical Characterization of Composite Cathode Material LiFePO4/C

WU Yu-Ling, PU Wei-Hua, REN Jian-Guo, JIANG Chang-Yin, WAN Chun-Rong   

  1. (Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 102201, China)
  • Received:2011-05-27 Revised:2011-08-21 Published:2012-04-10 Online:2012-03-12
  • About author:WU Yu-Ling. E-mail: yuling1521@126.com
  • Supported by:
    973 Program (2007CB209705);863 Program (2009AA035201);Research Fund of Tsinghua University (2009;THZ08064)

Abstract:

Nano FePO4·xH2O powders were synthesized by controlled crystallization method, using Fe(Ⅲ) compound as the iron source. The nano FePO4·xH2O powders were pretreated at 500℃ for 4?h in air to obtain nano FePO4 precursor. Then the olivine nano LiFePO4/C composites were obtained through carbonthermal reduction process at different temperatures. The structure, morphology, physicochemical properties and electrochemical properties of the nano FePO4·xH2O powder, FePO4 precursor and LiFePO4/C composites synthesized at different temperatures were characterized in detail by thermogravimetric/differential scanning calorimeter (TG/DSC), X-ray diffraction (XRD), scanning?electron?microscope (SEM), Brunauer-Emmett-Teller (BET) surface area measurement and electrochemical measurement. The results show that the nano LiFePO4/C composite calcined at 700℃ for 10?h has fine particle sizes of about 40-100?nm .The BET test shows that the as-prepared nano LiFePO4/C composite has great specific surface area of 79.8 m2/g. The nano LiFePO4/C composite cathode material can deliver an initial discharge capacity of 156.5, 134.9, 105.8, 90.3 and 80.9 mAh/g in the voltage range of 2.5-4.2?V, at rate of 0.1C, 1C, 5C, 10C and 15C respectively, which exhibits good rate performance. The nano LiFePO4/C composite also demonstrates excellent cyclic performance.

Key words: controlled crystallization method, LiFePO4/C, nano, lithium ion battery

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