The interaction mechanisms and performance of hydrophilic and hydrophobic ILs with varying water content for supercapacitors. (a) The chemical structures of the five ILs utilized in this study. (b) Heatmap of specific capacitance of the supercapacitors based on the five ILs with varying water contents under a current density of 0.2 A/g. (c) Schematic of water-ion interactions in hydrophilic and hydrophobic ILs.