Characterization of ionic liquid dynamics within composite graphene-ionic liquid supercapacitor electrodes

Supercapacitors are a promising renewable alternative to devices for mobile power supply. Rapid energy storage is achieved via the formation of a double-layer of electronic and ionic charge at the electrode/electrolyte interface. Active material pore structure/surface area and distribution of ions that bind to the electrode surface are key performance indicators. Commercially used activated carbons demonstrate adequate gravimetric energy density, Eg, but low density leads to poor volumetric energy density, Ev. Graphene is an ideal candidate, whilst reduced graphene oxide exhibits greater capacitance. Electrode pore utilization can be increased by greater electrolyte pore integration whilst energy density can be increased by use of large electrochemical voltage window electrolytes. Ionic liquids (IL) have thus become promising next-generation electrolytes. Here we will study the dynamics of IL confined within the intralayer voids; these together with our previous structural characterisation will provide further insight to the charging mechanism within this novel electrode system and aid our understanding of the structure-property relationships at different compositions.