Frequency dependence of the electrical impedance of electrolytic cells: The role of the ionic adsorption/desorption phenomena and the Stern layer

The frequency dependence of the electrical impedance of two cells filled with a water solution of KCl, identical in all the aspects, differing only in the thickness, is investigated. The experimental data for the real and imaginary parts of the electrical impedance of the investigated samples at low frequency can be interpreted by taking into account the adsorption–desorption phenomenon at the limiting surfaces and the presence of a Stern layer. This result allows to use the impedance spectroscopy technique to determine the adsorption and desorption coefficients entering in the kinetic equation at the interface.