Characterization of supercapacitors using singlewalled carbon nanotube electrodes

The key factors determining the performance of supercapacitors using singlewalled CNT electrodes were investigated. We obtained a maximum specific capacitance of 180 F/g and a measured power density of 20 kW/kg at the energy density of 7 Wh/kg in a solution of 7.5 N KOH. The specific surface area and the specific capacitance increase with increasing annealing temperatures of the sample. It was found that most of the BET surface area of the electrode contributes to the theoretically estimated specific capacitance. Minimization of the contact resistance is independent of the specific capacitance but directly related to the maximization of the power density.