Preparation of carbon/carbon composite xerogels from resorcinol-formaldehyde and cotton fiber for electric double layer capacitor

Abstract

This research used carbon/carbon composite xerogels as an electrode for EDLCs. Cotton fibers were blended with polymer gel which was synthesized through polycondensation between resorcinol and formaldehyde. The reaction was catalyzed by Na2CO3 with distilled water as a solvent. Resorcinol-formaldehyde sol was poured into a vial containing cotton fibers. After gelation at room temperature and curing at 90 oC for a week, the resulting porous monolith was sliced into thin wafers. Then, the composite wafers were exchanged with tert-butyl alcohol, dried by vacuum drying and performed by pyrolysis at a various temperature under a nitrogen atmosphere, respectively. Effect of %cotton fibers loading (0-40 wt%), pyrolysis temperatures (600 – 1000 oC) and CO2 activation time (30, 60 and 90 min) were studied. The microstructure and the physical properties were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, nitrogen adsorption-desorption, and scanning electron microscopy. The electrochemical performance of the carbon/carbon composite xerogels were analyzed in 4M potassium hydroxide aqueous solutions by potentiostat in cyclic voltammetry and galvanostatic charge-discharge mode. The activated carbon/carbon composite xerogels, which is 10 wt.% cotton fibers and CO2 activation 90 min, have the highest specific capacitance.