Chemical Research in Chinese Universities ›› 2018, Vol. 34 ›› Issue (3): 444-450.doi: 10.1007/s40242-018-8003-7

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Effect of VO43- Substitution on the Electrochemical Properties of a LiSn2(PO4)3 Anode Material

FENG Xiaojing1, HE Jun1, WANG Xiaoran1, WANG Gongkai1,2,3, WANG Xin1, PENG Huifen1,2,3   

  1. 1. School of Material Science & Engineering, Hebei University of Technology, Tianjin 300130, P. R. China;
    2. Research Institute for Energy Equipment Materials, Hebei University of Technology, Tianjin 300130, P. R. China;
    3. Tianjin Key Laboratory of Materials Laminating Fabrication & Interface Control Technology, Hebei University of Technology, Tianjin 300130, P. R. China
  • Received:2018-01-04 Revised:2018-03-19 Online:2018-06-01 Published:2018-04-16
  • Contact: PENG Huifen E-mail:peng@hebut.edu.cn
  • Supported by:
    Supported by the Natural Science Foundation of Hebei Province, China(No.E2016202358).

Abstract: VO43- anion was used to partially substitute for PO43- in the Nasicon compound of LiSn2(PO4)3 via a sol-gel method. XRD analysis revealed that the VO43--substituted samples did not have a single LiSn2(PO4)3 phase, and some secondary phases like SnO2 and SnP2O7 appeared. Introduction of the VO43- anion did not prevent the LiSn2(PO4)3 compound from decomposing during the initial lithiation; however the VO43- anion substitution remar-kably enhanced the rate capability and cycling performance of the products because they reduced the charge transfer impedance, increased the lithium ion diffusion, and strengthened the role of the Li3PO4 matrix due to the precipitation of the Li3VO4phase. Of the substituted samples, the sample with a nominal composition of LiSn2(PO4)2.5(VO4)0.5 delivered a capacity of 449.2 mA·h/g at a rate of 0.25 C after 25 cycles and 373.8 mA·h/g at 2 C rate. Those values surpassed some previous reports on LiSn2(PO4)3 and the LiSn2(PO4)3/C composites. Accordingly, the partial substitution of phosphorus by vanadium in LiSn2(PO4)3 is a feasible technique to remarkably improve its electrochemical properties.

Key words: Sn-based material, Anode material, LiSn2(PO4)3, VO43- substitution, Electrochemical property