Modeling of metal electrodeposits: Analytical solutions - Comment

When the equations of ionic motion for electrodeposition in a one-dimensional cell filled with a dilute binary electrolyte are solved under fixed-boundary conditions, a diffusion-limited current, independent of applied potential, is obtained. This result is well expected in the framework of the quasineutrality approximation. In this framework, the assumption by Huang and Hibbert [Phys. Rev. E. 52, 5065 (1995)] of an electrical-migration term in the evolution equation for the concentration is incorrect. However, a term of the same form, though smaller, may appear either from the concentration dependence of the mobilities or from an electroosmotic effect if the electrolyte is embedded in a gel or a porous medium.