基于容量参数的二次电池嵌入型电极材料固相扩散系数的测定方法  

Determination of solid diffusion coefficient of insertion-host electrode materials based on capacity parameter

作　　者：唐新村[1] 金乐[1] 刘畅[1] 

机构地区：[1]中南大学化学化工学院,长沙410083

出　　处：《中国有色金属学报》2005年第9期1431-1435,共5页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(20406024);中南大学博士后基金资助项目(7600)

摘　　要：介绍了一种以容量参数为主变量的测定锂二次电池中电极材料固相扩散系数的方法.该方法只需颗粒半径这一辅助参数,通过球型扩散模型建立了恒流-恒压充电容量(RPG)比,进一步发展成为容量间歇滴定技术(CITT).采用RPG法可在较宽的电压范围内测定嵌入型电极材料的平均固相扩散系数,实验结果重现性好.由RPG法测得0～1.5 V时锂离子在石墨电极中的平均固相扩散系数值为1.055×10-10cm2/s.由CITT技术测得锂离子在LiMn2 O4中的固相扩散系数在3.95 V和4.12 V左右存在个两个极小峰,且随着循环次数的增加,扩散系数值逐渐增大.A method of determining the solid diffusion coefficient of electrode materials in the lithium battery was introduced, where the capacity was the main variable. This method needs only one complementary parameter （ the radius of insertion-host particle, R） . Based on the ratio of potentio-charge capacity to the galvano-charge capacity （RPG） by the spherical diffusion model, the method was developed to the capacity intermittent titration technique （CITT）. By RPG method, the average solid diffusion coefficient of insertion-host materials can be determined at a relativly wide range of voltage. The Li^＋ diffusion coefficients in graphite were determined as 1. 055 × 10^-10 cm^2/s in the voltage range from 0 to 1.5 V. The Li^＋ solid diffusion coefficients in LiMn2O4 were determined at different galvano-charge currents. Results shows that the Li^＋ solid diffusion coefficients reach the minimum at the voltage of 3.95 and 4.12 V, and the diffusion coefficients increase with the increasing circulation times. So by CITT method, the solid diffusion coefficient of electrode materials at different charge-discharge circulations can be determined conveniencely.

关 键 词：固相扩散系数 容量参数 嵌入型电极材料 锂二次电池 

分 类 号：O646[理学—物理化学]