Preparation of carbon aerogel electrodes for supercapacitor and their electrochemical characteristics

Abstract

A new process is presented for synthesizing the supercapacitor electrodes of carbon aerogel via pyrolyzing resorcinol-formaldehyde (RF) aerogel, which could be cost-effectively obtained by ambient drying of wet RF-gels instead of conventional supercritical drying. Defect free RF-aerogels instead of conventional supercritical drying. Defect free RF-aerogels with the linear shrinkage of less than 8% could be manufactured by ambient-drying of wet RF-gels. Carbon aerogels with high strength were prepared via pyrolyzing RF-aerogels in N₂ atmosphere. The specific surface area (< 600 m²/g) and the electrical conductivity (∼ 50 S/cm) of carbon aerogels varied in sensitivity with the pyrolysis condition, while their densities (0.6 g/cm³) and porosities (70%) were found to be almost constant. Post heat-treatment of carbon aerogels around 300^∘C in air atmosphere was very effective for improving the electrochemical properties of electrodes. The carbon aerogel electrode pyrolyzed at 800∘C showed the specific capacitances of about 40 F/g in H₂SO₄ electrolyte solution and 35 F/g in KOH solution.