Electrochemical Properties of High-Power Supercapacitors Using Single-Walled Carbon Nanotube Electrodes

We have investigated the key factors determining the performance of supercapacitors constructed using single‐walled carbon nanotube (SWNT) electrodes. Several parameters, such as composition of the binder, annealing temperature, type of current collector, charging time, and discharging current density have been optimized for the best performance of the supercapacitor with respect to energy density and power density. We find a maximum specific capacitance of 180 F/g and a measured power density of 20 kW/kg at energy densities in the range from 7 to 6.5 Wh/kg at 0.9 V in a solution of 7.5 N KOH (the currently available supercapacitors have energy densities in the range 6–7 Wh/kg and power density in the range 0.2–5 kW/kg at 2.3 V in non‐aqueous solvents). Supercapacitors constructed using single‐walled carbon nanotube electrodes (SWNTs): What are the key factors determining their performance? This question is answered and several parameters—e.g., composition of binder, annealing temperature, charging time—optimized with respect to energy and power density are presented. The Figure is a field‐emission SEM image of as‐grown SWNTs, showing entanglements and crosslinking.