摘要
用循环伏安、交流阻抗和电位阶跃法研究了平板高有序热解石墨 (HOPG)电极在 1 mol/ L Li PF6 和体积比为 1∶ 1的 EC/ DMC溶液中的电化学行为 .结果表明 ,石墨的嵌锂反应仅发生在边界面上 .随着嵌锂量的增加 ,表面 SEI膜的电阻和嵌入反应的极化电阻减小 .用交流阻抗谱和电位阶跃方法测定的锂在高有序热解石墨中的扩散系数一致 ,并随充电程度的增加而显著减小 .在电极电位 (vs.Li/ Li+ ) 0 .2～ 0 .0 5 V区间 ,扩散系数由 1 0 - 1 1 cm2 / s下降到 1 0 - 1 2 cm2 /
The diffusion coefficient of lithium in Highly Oriented Pyrolytic Graphite(HOPG) was measured by using electrochemical impedance spectra(EIS) and potential step methods in 1 mol/L LiPF 6, \{ V (EC)∶ V (DMC)=\}1∶1 solution. It was found that the resistance of SEI film and the polarization resistance decreased with the increase of lithium intercalation degree. A agreement was obtained between the diffusion coefficient values measured from these two methods. The diffusion coefficient of lithium in HOPG decreased from 10 -11 cm 2/s to 10 -12 cm 2/s in the potential region of 0.2-0 05 V.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2002年第7期1375-1378,共4页
Chemical Journal of Chinese Universities
基金
国家自然科学基金 (批准号 :2 893 3 0 90 )
关键词
高有序热解石墨
锂离子电池
负极
扩散系数
嵌入反应
材料
石墨电极
Highly oriented pyrolytic graphite
Negative electrode of lithium ion battery
Diffusion coefficient
Intercalation reaction
