An electrochemical ac impedance study of LixNi0.75Co0.25O2 intercalation electrode

An EIS study on LixNi0.75Co0.25O2 intercalation cathode has been performed. The spectra have been interpreted on the basis of an equivalent circuit based on a combination of a Voigt-type analog (Li ion migration through surface film and charge transfer) in series with a Warburg type element, an element that takes into account the electronic resistance of the material and a capacitor (Li accumulation).