Differential Capacitance of Room Temperature Ionic Liquids: The Role of Dispersion Forces

We investigate theoretical models of room temperature ionic liquids, and find that the experimentally observed camel-shape of the differential capacitance is strongly related to dispersion interactions in these systems. At low surface charge densities, the loss of dispersion interactions in the vicinity of the electrodes generates depleted densities, with a concomitant drop of the differential capacitance. This behavior is not observed in models where dispersion interactions have been removed.