Impedance spectroscopy of surfaces described by irreversible thermodynamics

It is shown how one can derive the impedance of a polarized electrode surfa ce from irreversible thermodynamics. The oxygen electrode is studied as an example. A Nyquist diagram is constructed for the case that the electrode c onducts by electrons only, and the electrolyte conducts by oxygen ions or v acancies. The electrode surface contributes to the diagram with two semi-ci rcles. One semi-circle is due to production of dipoles from adsorbed oxygen atoms. The other is due to the dipole moment of the ion-electron hole pair .