Interfacial Reactions Between Graphite and Diethyl Carbonate Solutions Containing Different Concentrations of Li+

The electrochemical reactions occurring at graphite electrodes in lithium-ion batteries using diethyl carbonate (DEC) electrolytes containing different concentrations of LiClO4 (0.85 and 2.82 mol kg-1) were examined. The poor charge-discharge performance of the electrode in the 0.85 mol kg-1 LiClO4 in DEC was improved considerably when employing 2.82 mol kg-1 LiClO4 in DEC as the electrolyte. In situ electrochemical atomic force microscopy analysis revealed that an effective film had formed on the graphite surface after the first potential cycle when using the more concentrated solution. Charge-discharge analysis revealed that the nature of the film was significantly different from that formed in ethylene carbonate-based solutions.