【摘要】 采用循环伏安技术、交流阻抗电化学测试方法研究了BF石墨电极在1mol·L-1LiPF6和体积比为1∶1∶1的EC/DMC/DEC溶液中的成膜过程和嵌脱锂过程,实验结果表明:在本研究体系中包覆石墨电极的成膜电位1.5～0.6V(vs.Li/Li+);其嵌脱锂电极过程主要受锂离子在石墨体相中的扩散步骤控制;并且随着嵌锂量的增大,锂离子扩散系数逐渐减小,锂离子穿过SEI膜的膜阻抗及电化学反应阻抗随之增大。在嵌锂过程中锂离子扩散系数的数量级在10-12～10-13cm2·s-1之间。更多还原

【Abstract】 The formation of solid electrolyte interface(SEI) and the process of insertion and deinsertion of lithium ion in graphite were investigated by means of cyclic voltammetry technique and electrochemical impedance spectroscopy in 1mol· L-1 LiPF6,V(EC):V(DMC):V(DEC)=1∶ 1∶ 1 solution.The results show that the SEI formation potential on graphite in the first cathodic process is 1.5-0.6V.It was found that the electrode process was confirmed to be rate-controlled by the diffusion of lithium in the graphite and the diffusion coefficient values decreased from 10-12 cm2· s-1 to 10-13 cm2· s-1,the resistance of SEI film and the electrochemical reaction resistance increased with the increase of lithium intercalation degree.更多还原