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化学学报
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化学学报 ›› 2007, Vol. 65 ›› Issue (1): 10-16. 上一篇    下一篇

研究论文

Li3V2(PO4)3电极过程及其锂离子脱嵌动力学研究(I)

刘素琴, 李世彩, 黄可龙*   

  1. (中南大学化学化工学院 长沙 410083)
  • 投稿日期:2006-05-29 修回日期:2006-07-18 发布日期:2007-01-14
  • 通讯作者: 黄可龙

Investigations on the Electrode Process and Kinetics of Li-ion Extraction/Insertion in Li3V2(PO4)3 (I)

LIU Su-Qin; LI Shi-Cai; HUANG Ke-Long*   

  1. (College of Chemistry & Chemical Engineering, Central South University, Changsha 410083)
  • Received:2006-05-29 Revised:2006-07-18 Published:2007-01-14
  • Contact: HUANG Ke-Long

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采用溶胶凝胶法合成了Nasicon化合物Li3V2(PO4)3, 采用X射线衍射(XRD)对产品进行了物相分析. 采用充放电测试, 循环伏安(CV)研究了化合物的电化学性能和锂离子的脱嵌过程, 计算出Li＋在固相中的扩散系数(10－8 cm2•s－1); 采用交流阻抗测试(EIS)研究了Li3V2(PO4)3的电极过程; 对两种类型的阻抗图谱提出不同等效电路模型并对结果进行了拟合; 研究了Li3V2(PO4)3电极过程动力学以及新鲜电极界面在充放电过程中的变化特性.

关键词: 锂离子动力学, 锂离子脱嵌, Li3V2(PO4)3, 交流阻抗

The compound of monoclinic Li3V2(PO4)3, synthesized by sol-gel method, was certified by X-ray diffraction and its electrochemical performance was investigated by charge/discharge method, cyclic voltammetry and differential capacity data (Electrochemical Voltage Spectroscopy, EVS). Electrochemical impedance spectroscopy (EIS) using a two-electrode system in a frequency range from 1 MHz to 0.01 Hz was conducted on a Li3V2(PO4)3 electrode, and two different equivalent circuits was proposed for fitting the experimental results, consequently to evaluate the kinetics of Li-ion extraction and insertion at Li3V2(PO4)3 and its evolution of surface/interface.

Key words: Li-ion kinetics, extraction and insertion of Li＋, Li3V2(PO4)3, electrochemical impedance spectroscopy