An AC impedance spectroscopic study of LixCoO2 at different temperatures

An AC impedance spectroscopic study of the LixCoO2 electrode in the temperature range of 0-30 degreesC is presented. The results are interpreted on the basis of an equivalent circuit that includes elements related to the electronic and ionic transport in addition to the charge transfer process. The evolution of the impedance spectra with the temperature shows that a thermally activated insulator to metal transition occurs at the beginning of the deintercalation process. At intermediate intercalation degrees. the effects of the finite electronic conductivity of the material and of the charge transfer process clearly appear as separate features in the spectra at low temperature.