Immittance response of an electrolytic cell in the presence of adsorption, generation, and recombination of ions

Effects of the adsorption–desorption process on the immittance response of an electrolytic cell are theoretically investigated in the framework of the diffusional Poisson–Nernst–Planck (PNP) continuum model, when the generation and recombination of ions is taken into account. The analysis is carried out by searching solutions for the drift–diffusion equation coupled to the Poisson’s equation relating the effective electric field to the net charge density. The effect of different ion mobilities on the immittance, i.e., situations with equal and different diffusion coefficients for positive and negative ions, are considered. A general exact expression for the admittance in the context of the linear approximation is obtained.