Computer simulation of the potential distribution in an electrochemical cell is a useful technique for estimating the ohmic drop and the potential gradient at any point in solution. Results of such simulations can be used in several applications. Since optimal location of a reference electrode depends, in part, on avoiding large potential gradients, calculations can be useful in determining where substantial gradients occur. One can alter the current and potential distribution by changing the cell geometry; the effects of changes can be quantitatively determined from a simulation. Knowledge of ohmic drop in the electrolyte is also of interest in applications such as cathodic protection, where large potential losses can lead to insufficient protection.
In this paper we illustrate the use of computer simulation for the computation of potential and current distributions from which we evaluate ohmic drop and surface overpotential. We used the finite-difference technique for several problems in which both field effects and electrode kinetics were important. Approximations introduced to reduce the complexity were assessed by comparing numerical results with analytical solutions.
Electrochemical systems of practical interest, the disk electrode and plane electrodes with gas bubbles in the electrolyte, were studied. In one variation, we showed the effect of recessing a disk electrode in the insulating plane. In a second set of calculations, we simulated a gas bubble layer near an electrode and determined the effects of increasing void fraction in the bulk electrolyte.