Surface modification mechanism of lithium electrode with 1,3-Dioxolane

Abstract:

Lithium metal electrode was pre-treated with 1,3-dioxolane in order to study the surface modification mechanism on it,then coin cells were assembled with LiCoO2 cathode and the cycle and discharge performance were tested.The electrochemical impedance spectroscopy(EIS) were employed on the cells in the 10th and 70th cycle at different discharge voltage,and a reasonable equivalent circuit was proposed to analyze the changement of impedance values correspondingly.It is found that the electrode properties are improved greatly.The EIS analysis shows that 1,3-dioxolane can form a stable SEI layer on the surface of Li electrode.This layer is able to enhance the interfacial compatibility without depressing Li ions kinetic behavior.The reason for the performance of lithium electrode getting worse in cycleability is the increment of surface membrane resistance and charge transfer resistance,which leads to the higher lithium ions migration resistance and electron transfer resistance.