Numerical modeling of non-steady-state ion transfer in electrochemical systems with allowance for migration

Numerical methods that are used for modeling non-steady-state ion transfer in electrochemical systems and account for the diffusion, migration, convec tion, and homogeneous chemical reactions are analyzed. It is shown that the violation of the electroneutrality condition (ENC) in the process of numer ical solution is due to the difference equations being inconsistent with th e initial differential equations. Difference schemes for numerical calculat ion of transfer processes, which make it possible to split a set of coupled equations, are designed and conditions for their stability are determined. The explicit difference scheme is self-consistent, i.e. it ensures that EN C is rigorously met. In the implicit difference scheme, ENC is probably vio lated when splitting the set of equations. To restore electroneutrality of the medium, it is proposed to use a physically substantiated analytical rel ation for the space charge relaxation under the action of a strong electric field.