Constant-current unsupported electrolysis in a thin cell: a comparative study of analytical and simulative modelling

The features of digital simulation, analytical modelling and semianalytical modelling are contrasted. Two of these approaches are applied to an electrolysis experiment in which a neutral substrate, in solution in a thin-layer cell, is oxidized to an ionic product. The resistance of the cell, initially high, diminishes with time in the constant-current experiment. The cell voltage reflects both the decreasing ohmic polarization and the increasing concentration polarizations. Ultimately, exhaustion of substrate at the anode leads to a catastrophe at a transition time. The experiment is modelled simulatively and analytically and the results are compared. A book-keeping procedure is employed to assess the reliability of the numerical model.