锂在高有序热解石墨(HOPG)电极中的扩散系数  

Diffusion Coefficient of Lithium for Intercalation in Highly Oriented Pyrolytic Graphite

作　　者：努丽燕娜[1] 万传云[1] 严曼明[1] 庄继华[1] 江志裕[1] 

机构地区：[1]复旦大学化学系,上海200433

出　　处：《高等学校化学学报》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 )

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.

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 

分 类 号：TM912[电气工程—电力电子与电力传动] O646.5[理学—物理化学]