Graphene with three-dimensional architecture for high performance supercapacitor

Mesoporous graphene with three dimensional structure (3dGR) is prepared by a modified Hummers method and a simple solvent treatment. The solvent-treated graphene nano-sheets show wrinkled structure and agglomerate to form the mesoporous structure. The pore size distribution of 3dGR based on density functional theory (DFT) shows the pore size ranging from 2.3-40 nm. 3dGR shows excellent electrochemical behaviors in both aqueous and organic electrolytes, even though it has fairly small surface area of only 81.7 m(2)/g. For 3dGR, a capacitance of 341 F/g and energy density of 16.2 Wh/kg are acquired in alkali electrolyte, while those values are 166 F/g and 52.5 Wh/kg respectively in organic electrolyte. In addition, because of the high packing density of 3dGR, higher volumetric power densities of 20.7 and 67.2 Wh/L in alkali and organic electrolytes are obtained. After 1000 cycles of galvanostatic charge/discharge tests, over 96% and 86% of the original capacitance can be retained in alkaline and organic electrolytes. (C) 2013 Elsevier Ltd. All rights reserved.