Electric response of asymmetric electrolytic cells to small AC signals

We present an extended theory for the electric response of an electrolytic cell with two different electrodes to a small amplitude external ac stimulus. In this case, the two electrodes limiting the cell are different in the sense that the spatial dependencies of the dynamical quantities characterising the system have not a well defined symmetry, with respect to the electrodes. This requires extending the Poisson-Nernst-Planck model to solve the fundamental equations allowing for the analytical determination of the electric impedance of the cell. The new theoretical framework opens the pathway to describe asymmetric electrolytic cells limited by conductive or adsorbing-desorbing boundaries.