库仑法和电化学阻抗法测量LiFePO_4锂离子扩散系数  

Determination of Li-ion Diffusion Coefficient via Coulometric Titration and Electrochemical Impendence Method

作　　者：王连亮[1,2] 马培华[1] 张琨[1,2] 高成花[1,2] 阎春燕[1,2] 

机构地区：[1]中国科学院青海盐湖研究所,青海西宁810008 [2]中国科学院研究生院,北京100039

出　　处：《盐湖研究》2009年第3期52-55,共4页Journal of Salt Lake Research

基　　金：青海省重点科技攻关项目(2006-G-168)资助

摘　　要：库仑法和电化学阻抗法是测量锂离子扩散系数有效的测量手段。以实验室自制的LiFePO4为实验电池正极材料,介绍如何用库仑法和阻抗法测试并计算电极材料的锂离子扩散系数。库仑法计算得到锂离子扩散系数由Li1-xFePO4(x=0)的9.6×10-9cm2.s-1变化为Li1-xFePO4(x=0.7)的1.1×10-11cm2.s-1。用阻抗法的两种模型,分别计算了Li1-xFePO4(x=0.65)的电池材料的锂离子扩散系数,结果分别是8.5×10-11cm2.s-1和3.1×10-12cm2.s-1。三种方法的计算结果接近。Li-ion diffusion coefficient can be effectively obtained from coulometric titration and electrochemical impendance method. The paper takes self-made LiFePO4 as an example to calculate the Li-ion diffusion coefficient by using coulometric titration and electrochemical impendence method. The results of coulometric titration shows that it varies from 9.6 x 10-gcm2·s-1 to 1.1 × 10-11 cm2 ·s-1 as a function of x in Li1-xFePO4 when xequals 0 to 0. 7. Based on two different models of electrochemical impendance spectroscopy, the paper calculates the Li-ion diffusion coefficient of Li1-xFePO4 （x = 0. 65 ） and the results are 8.5 x 10-11 cm2·s-1 and 3.1×l0-12cm2·s-1 respectively. Three results are in good agreement.

关 键 词：库仑滴定 电化学阻抗 锂离子扩散系数 正极材料 锂离子电池 

分 类 号：O646.21[理学—物理化学] O546.54[理学—化学]