Simulation techniques for predicting current and voltage distribution across electrode surface and electrolyte

Abstract

One of the prerequisites in all electrochemical processes is to achieve uniform distribution in potential and current across the electrodes and the cell. Although parallel plate electrodes encompass a preferable uniformity in distribution, it tends to get attenuated based on the geometric variables like electrode spacing and width of electrodes. The purpose of this paper is to analyse underlying aspects associated with these distributions and to indicate how they can be visually represented. A mathematic treatment is carried out to generate an expression for potential distribution across electrolyte at the electrode surface with a varying ratio of width of electrode to electrode spacing (L/H). Segregation of L/H, where improved uniformity could be attained, is evaluated based on a graphical study. In the latter part, simulation studies were conducted to examine the profile of both current and potential in a typical parallel plate electrochemical cell so as to get a visual representation. It is clear that the edge effects are strongly modified by the electrode distance, which could be quantified by the divergence parameter (Ψ) values. Hence, these values are related to the non-uniformity grade, increasing the zones of high local current densities. The understanding of this effect could be worthy to improve the designs of this kind of cells employed in the large scale plating industry. In short, this study is proposed to be a cornerstone for practicing electrochemical engineers in designing electrodes and electrochemical cells for various applications.