Activated carbon–carbon nanotube nanocomposite coatings for supercapacitor applications

Electrochemical double layer capacitor cells were fabricated based on electrodes with activated carbon (AC) coating as the host material, targeting large energy storage. Highly dispersed multiwall carbon nanotubes (MWNTs) were added to form nanocomposite coatings, used as electrodes targeting high-power performance for very low content of MWNTs. 1 M tetraethylammonium tetrafluoroborate–propylene carbonate solution was used as organic electrolyte. The resulting cells were characterized using impedance spectroscopy, cyclic voltammetry, and galvanostatic charge–discharge tests. It was concluded that at optimum composition of AC–MWNT coatings both power and energy densities are raised whereas further increase of the MWNT content would increase the power density but decrease the energy density.