Impedance spectroscopy of an electrolytic cell limited by ohmic electrodes

We investigate the influence of the ohmic character of the electrodes on the impedance spectroscopy of a cell of a dielectric liquid containing ions. According to our calculations, the finite conductivity of the electrodes is responsible for an increasing of the real part of the electrical impedance in the low frequency range. It follows that the anomalous increasing of the resistance of the cell, experimentally observed by several groups, could be related also to the exchange of charge at the electrodes. Our analysis is based on a generalization of the Butler-Wolmer equation, for small values of the external voltage. (c) 2007 American Institute of Physics.