Small-signal ac response of an electrolytic cell with recombining space charge

A simple model to evaluate the impedance of a cell in the presence of the generation and recombination of charges is proposed. The analysis is performed by considering a typical asymmetric cell having one electrode perfectly blocking and the other electrode perfectly transparent. The dependence of the impedance of the cell, in the shape of a slab, on the recombination coefficient is investigated. We obtain approximated expressions for the impedance of the cell valid in the low and high frequency regions. The frequencies defining the regions where approximated expressions hold are deduced by means of the asymptotic expansions for the real and imaginary parts of the electrical impedance of the cell.