Electric double layer in molten salts: Toward a more realistic model

Abstract

Results of a Monte Carlo simulation of the electrode | molten salt interface are reported. The system was modelled by soft ions using the repulsive part of the Lennard-Jones potential in contact with a soft wall, also modelled by the Lennard-Jones repulsive part. Calculations were carried out for the realistic values of parameters (van der Waals diameter of the ion, d=3Å, relative permittivity εr=10, packing fraction η=0.35), which led to the properties of the investigated system being comparable with real ones (melting temperature T=1100K and bulk concentration c=20.57M). Calculations were carried out for temperature T=1400K. The differential capacitance curve had a bell shape and was found to be more flattened when compared with the one obtained for the restricted primitive model. This difference was explained by the different structure of the charged layers compared with that for the restricted primitive model. With increasing electrode charge, the charged layers were found not to change their thickness significantly, though their charge density increased.