Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (1): 88-94.doi: 10.3866/PKU.WHXB201311072

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

Preparation and Performances of C-LiFePO4/Polytriphenylamine Composite as Cathode Material for Lithium-Ion Batteries

SU Chang1, HUANG Qi-Fei1, XU Li-Huan2, ZHANG Cheng1   

  1. 1 State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, Zhejiang University of Technology, Hangzhou 310014, P. R. China;
    2 College of Chemical Engineering, Shenyang University of Chemical Technology, Shenyang 110142, P. R. China
  • Received:2013-08-06 Revised:2013-11-06 Published:2014-01-01
  • Contact: XU Li-Huan, ZHANG Cheng E-mail:xulihuanss@163.com;czhang@zjut.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (51003095, 51103132) and Research on Public Welfare Technology Application Projects of Zhejiang Province, China (2010C31121).

Abstract:

An olivine LiFePO4/carbon (C-LiFePO4) nanocrystallinematerial was prepared using a low-temperature solvothermalmethod, followed by a high-temperature post-annealing process. Then polytriphenylamine (PTPAn)-modified C-LiFePO4 (C-LiFePO4/PTPAn) was prepared, as a composite for novel cathodes for lithium-ion batteries, by solution blending of the C-LiFePO4 nanocrystallinematerial and the electroactive conducting polymer PTPAn. The effects of PTPAn coating of the C-LiFePO4/PTPAn samples were investigated using X-ray diffraction (XRD), scanning electronmicroscopy (SEM), transmission electronmicroscopy (TEM), electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge testing. The results indicated that the solution blending method produced a compact PTPAn coating on the C-LiFePO4, providing an effective electronic/ionic conducting pathway and enhancing the electrochemical activities of C-LiFePO4-based composites. The C-LiFePO4/10%(w) PTPAn electrode displayed an improved initial discharge capacity of 154.5mAh·g-1 at 0.1C, a superior high-rate performance discharge capacity of 114.2 mAh·g-1 at 10C, and excellent cycling stability.With further increases in the PTPAn content of the coating on the C-LiFePO4/PTPAn composite, the electrochemical properties of the composite decreased. Electrochemical impedance measurements also demonstrated that the PTPAn coating significantly decreased the charge-transfer resistance of the C-LiFePO4 electrode.

Key words: Lithium-ion battery, Polytriphenylamine, Cathode material, Solution blending method, Electrochemical property

MSC2000: 

  • O646