物理化学学报 >> 2007, Vol. 23 >> Issue (01): 129-133.doi: 10.3866/PKU.WHXB20070127

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磷酸铁锂在饱和硝酸锂溶液中的电极过程动力学

黄可龙;杨赛;刘素琴;王海波   

  1. 中南大学化学化工学院, 长沙 410083
  • 收稿日期:2006-07-31 修回日期:2006-09-12 发布日期:2007-01-08
  • 通讯作者: 黄可龙 E-mail:klhuang@mail.csu.edu.cn

Kinetics of Electrode Processes of LiFePO4 in Saturated Lithium Nitrate Solution

HUANG Ke-Long;YANG Sai;LIU Su-Qin;WANG Hai-Bo   

  1. College of Chemistry & Chemical Engineering, Central South University, Changsha 410083, P. R. China
  • Received:2006-07-31 Revised:2006-09-12 Published:2007-01-08
  • Contact: HUANG Ke-Long E-mail:klhuang@mail.csu.edu.cn

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摘要： 利用循环伏安法(CV)、充放电测试和恒电位间隙滴定技术(PITT)研究了LiFePO4在饱和LiNO3溶液中的电极过程动力学. 研究结果表明, LiFePO4在饱和LiNO3溶液中具有良好的电化学可逆性, 其首次放电比容量达116.2 mAh•g−1, 首次充放电效率达92%. CV法估算出氧化峰和还原峰处锂离子在LiFePO4中的扩散系数分别为4.3×10−11和3.8×10−11 cm2•s−1. 采用PITT测定出锂离子在LiFePO4中的扩散系数随电位的变化规律, 其在充电平台附近达到最小值5.5×10−11 cm2•s−1.

关键词: 水溶液锂离子电池, LiFePO4, 循环伏安法, 恒电位间隙滴定技术, 扩散系数

Abstract: Kinetics of electrode processes of LiFePO4 in saturated LiNO3 solution was investigated by analyses of cyclic voltammetry (CV), charge/discharge test, and potentiostatic intermittent titration (PITT). The results showed that LiFePO4 had good electrochemical reversibility in saturated LiNO3 solution. The first discharge capacity was about 116.2 mAh•g−1, and its charge/discharge efficiency was 92%. The lithium diffusion coefficients, corresponding to anodic peak and cathodic peak in LiFePO4, obtained from CV were 4.3×10−11 cm2•s−1 and 3.8×10−11 cm2•s−1. The lithium diffusion coefficients obtained from PITT varied with potentials, and the lowest value was about 5.5×10−11 cm2•s−1, coinciding with the voltage plateau region in the charge curves.

Key words: Aqueous lithium-ion battery, LiFePO4, Cyclic voltammetry, Potentiostatic intermittent titration technique, Diffusion coefficient