CALCULATION OF STEADY-STATE DISTRIBUTION OF CONCENTRATIONS AND POTENTIAL CONTROLLED BY DIFFUSION AND MIGRATION OF IONS

A numerical method is proposed for the calculation of concentration, potential, and current distributions in electrochemical cells controlled by diffusion and migration of ions. Thus a hypothetical variable v(x, y, t) is assumed to satisfy a differential equation which is similar to that of non-steady-state heat conduction and corresponds, at steady state, to Poisson's equation for the potential. The differential equation for v(x, y, t) and the diffusion-migration equations of ions are simultaneously solved by a finite difference method. Examples of calculation are given for single and mixed electrolyte solutions in one- and two-dimensional cells. The proposed method is applicable to systems in which bipolarity occurs.