Current supercapacitors under development for energy storage include various electrode materials ranging from metal oxides and carbon compounds such as graphene and carbon nanotubes to conductive polymers and their composite blends . Among polymer composites, typical electrode materials contain transition metal oxides such as MnO2, Fe2O3, NiO, Co2O3, CdO, and ZnO, and conductive polymers like polyaniline (PN), polypyrrole, and polyindole .