Transient ion fluxes, driven by an external electric field in a thin electrolytic cell with blocking electrodes

A numerical algorithm is developed to examine the transient processes in an electrolytic cell with blocking electrodes when an external electric field is switched on and switched off stepwise in time. The algorithm is applicable for arbitrary mobilities and valence numbers of the ions and for large electric potentials, but is limited at present to small cell thickness, up to about 20 D lengths. The ion charge fluxes and the displacement current contributing to the total current in the cell have been evaluated and analysed. The ion charge behaviour in the linear approximation regime (low excitation voltage) and nonlinear regime (high voltage) have been compared. The dependences of the polarization and diffusion relaxation times on the ion parameters (valence and mobility), on the cell length and on the external electric potential are studied.