Activated Graphene-Based Carbons as Supercapacitor Electrodes with Macro- and Mesopores

TLDR: The fabrication of highly porous graphene-derived carbons with hierarchical pore structures in which mesopores are integrated into macroporous scaffolds are demonstrated, which makes them potentially promising for diverse energy storage devices.

Abstract: Electric double layer capacitors (or supercapacitors) store charges through the physisorption of electrolyte ions onto porous carbon electrodes. The control over structure and morphology of carbon electrode materials is therefore an effective strategy to render them high surface area and efficient paths for ion diffusion. Here we demonstrate the fabrication of highly porous graphene-derived carbons with hierarchical pore structures in which mesopores are integrated into macroporous scaffolds. The macropores were introduced by assembling graphene-based hollow spheres, and the mesopores were derived from the chemical activation with potassium hydroxide. The unique three-dimensional pore structures in the produced graphene-derived carbons give rise to a Brunauer–Emmett–Teller surface area value of up to 3290 m2 g–1 and provide an efficient pathway for electrolyte ions to diffuse into the interior surfaces of bulk electrode particles. These carbons exhibit both high gravimetric (174 F g–1) and volumetric (∼10...