Electrolyte Effects on Disorder-Enhanced Capacitance in Nanoporous Carbons

The impact of pore structure and surface functionality on the capacitance of nanoporous carbons has been widely studied across different electrolytes, yet the role of electrolyte chemistry in structural disorder-driven and ion adsorption capacity-related capacitance remains largely unexplored. In this study, we investigate the relationship between capacitance and the degree of structural order in 20 nanoporous carbons using ionic liquid electrolytes, aiming to establish the generality of disorder-driven capacitance and explore its underlying mechanisms. Our results demonstrate that carbons with smaller graphene-like domains and larger ion adsorption capacities exhibit higher capacitance in 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF₄) ionic liquid, consistent with our previous findings in 1 M tetraethylammonium tetrafluoroborate (TEABF₄) in acetonitrile (ACN). More generally, we find that the capacitance of a given carbon remains similar across different ionic liquid and organic electrolytes, provided that the pores are accessible to the electrolyte ions. This study shows the generality of disorder-driven and adsorption-dependent capacitance in nanoporous carbons in organic and ionic liquid systems and suggests that factors such as the nature of the defects and how they affect quantum capacitance may play an important role in disorder-driven capacitance, ultimately providing insights for designing high-performance supercapacitor electrodes.