Mesoporous hollow carbons on graphene and their electrochemical properties

We report the formation of mesoporous hollow carbons with diameters of about 30–40 nm on a graphene (MHCG) surface formed using graphite, the surfactant Pluronic F-127, and porous silica on the graphene as a template to produce a sheet. The specific surface area of the sample produced is 1793.45 m 2 g −1 , which is hundreds of times larger than that of graphite (31.38 m 2 g −1 ). When applied to supercapacitor electrodes, the MHCG electrode exhibits outstanding maintenance of energy density above 30 W h kg −1 even under 1 kW kg −1 power density, which is attributed to extremely fast electron supply through graphene layers and facile penetration of electrolyte through highly-developed mesopores.