The effect of dispersion interactions on the structure and performance of electrical double layer of ionic liquids

A classical density functional theory has been used to study the structure and phase behavior of the electrical double layer of a dense ionic liquid. The model for IL consists of a trimer cation (with a charged head and two neutral segments) and a monomer anion. The effect of dispersion interactions on the density profile and differential capacitance curve has been investigated. Increasing the contribution of dispersion interactions leads to a camel-shape differential capacitance curve. In the case of bell-shape curve, the maximum of the differential capacitance increases with decreasing the dispersion forces. These observations are related to the depletion or accumulation of ions near electrode with zero or low surface charge density.