Electrochemical Impedance Analysis for Lithium Ion Intercalation into Graphitized Carbons

Electrochemical impedance spectroscopy (EIS) was employed to study electrochemical behaviors during intercalation of into graphitized carbon anode. Analysis was carried out on three regions of frequencies mainly below 0.3 V. The first depressed semicircle in the high‐frequency region had two‐dimensional characteristics and did not vary over the entire potential range. The second semicircle in the mid‐frequency region had a potential dependency above 0.3 V. Impedance spectra at the lower frequency region were attributed to the finite diffusion of , and the order of the chemical diffusion coefficient was approximately .