Polarization-Driven Enhancement of Energy Storage in Fullerene-Doped Ionic-Liquid Graphene Supercapacitors

Abstract

Classical molecular dynamics simulations were used to investigate the effect of fullerene C60 on the interfacial structure and electrostatic response of graphene-based supercapacitors containing the ionic liquid [Bmim][PF6]. Systems with different C60 loadings were analyzed within a fixed-charge framework, and polarized and nonpolarized fullerene descriptions were compared at the highest loading. The simulations show that C60 preferentially accumulates near the graphene/electrolyte interfaces, partially displacing adsorbed ions while preserving the layered structure of the electrical double layer. This interfacial redistribution reduces conventional ionic screening and increases the relative contribution of fullerene–graphene dispersion interactions. Although increasing C60 content lowers the calculated capacitance, the solvent-polarized fixed-charge model produces a larger corrected electrostatic potential difference and, consequently, a higher model-derived energy-density estimate than the corresponding nonpolarized model at the same fullerene loading. These results suggest that fullerene adsorption and solvent-induced charge anisotropy can jointly modulate the electrostatic response of ionic-liquid graphene supercapacitors. The reported values should be interpreted as comparative trends within the adopted molecular model rather than as direct predictions of experimental operating voltages.