The steady 1-dimensional electrolysis of a metal salt in a system with a supporting electrolyte was considered. The electrolyte in the system was assumed to comprise 3 ionic species, one of which took part in the electrode reactions. Attention was restricted to relatively common cases in which the transfer coefficient in the Butler-Volmer law for the electrode kinetics was equal to ½. For algebraic simplicity, most of the present work dealt with the special case where there were 2 cation species with charge numbers of 2 and 1, and one anion species with a charge number of unity. However, all of the results could be easily generalized to any set of charge numbers. In the special case of a binary electrolyte, an exact but simple expression was obtained for the polarization curve. Also, drops in the ohmic potential, the concentration over-potential in the electrolyte, and the surface over-potentials were calculated as functions of the electric current density. In the general case of 3 ionic species, an exact expression for the polarization curve was provided in an implicit form. For the diffusion layer configuration, an explicit expression for the polarization curve was given for a system with arbitrary charge numbers and a more general form of the Butler-Volmer law.

A.V.Sokirko, F.H.Bark: Electrochimica Acta, 1995, 40[12], 1983-95