Electrochemical behavior of mixed CmRF based carbon aerogels as electrode materials for supercapacitors

Carbon aerogels have been prepared using cresol (C-m), resorcinol (R) and formaldehyde (F) as starting materials in a sol-gel process. Drying of the mixed gels was performed at ambient pressure and pyrolysis of the aerogels followed at 1170 K. This is considered as an alternative economic route to the classic RF gels synthesis. The obtained mixed carbon aerogels (labeled as CmRF) have been investigated as electrode materials in supercapacitors. The electrochemical behavior was characterized by means of cyclic voltammetry and impedance spectroscopy. CmRF based carbon aerogel electrodes show a stable potential window in 1.0 M H2SO4 electrolyte and a promising charging performance. Mass-specific capacitances of up to 104 F/g and volume-specific capacitances of up to 77 F/cm(3) were obtained in CmRF based carbon aerogels made from 40%, cresol/60% resorcinol starting solutions. Using data obtained from nitrogen adsorption at 77 K, in addition, the dependence of capacitance on microstructure characteristics can be revealed. (C) 2003 Elsevier B.V. All rights reserved.