Impedance Spectroscopy of Surfaces Described by Irreversible Thermodyn amics

It is shown how one can derive the impedance of a polarized electrode surface from irreversible thermodynamics. The oxygen electrode is st udied as example. A Nyquist diagram is constructed for the case that the electrode conducts by electrods only and the electrolyte conducts by oxygen ions or vacancies. The electrode surface contributes to th e diagram with two semi-circles. One semi-circle is due to production of dipoles from adsorbed oxygen atoms. The other is due to the dipol e moment of the electroc-hole pair.