Journal of Power Sources, Vol.175, No.1, 651-656, 2008
Electric double layer capacitance on hierarchical porous carbons in an organic electrolyte
Nanoporous carbons were prepared by using colloidal crystal as a template. Nitrogen adsorption/desorption isotherms and transmission electron microscope images revealed that the porous carbons exhibit hierarchical porous structures with meso/macropores and micropores. Electric double layer capacitor performance of the porous carbons was investigated in an organic electrolyte of I M LiClO4 in propylene carbonate and dimethoxy ethane. The hierarchical porous carbons exhibited large specific double layer capacitance of ca. 120 F g(-1) due to their large surface areas. In addition, the large capacitance was still obtained at a large current density up to 10 A g(-1), which satisfies demands from the high power application such as hybrid electric vehicles. Capacitance analysis of the hierarchical porous structures revealed the contribution of meso/rnacropores and micropore to the electric double layer capacitance to be 8.4 and 8.1 mu F cm(-2), respectively. The results indicated electric double layer is formed even when solvated ions are larger than pore diameters. (c) 2007 Elsevier B.V. All rights reserved.
Keywords:porous carbon;micropore;electric double layer capacitor;organic electrolyte;hierarchical pore