Preparation and electrochemical characterization of NiO nanostructure-carbon nanowall composites grown on carbon cloth

► The CNWs were synthesized on carbon cloth by rf magnetron sputtering without any catalyst. ► Ni film was deposited on the synthesized CNWs by e-beam evaporator. Subsequently, the vacuum annealing process and oxygen plasma treatment were used to form the NiO nanostructures. ► NiO has several oxidation numbers that have quickly reversible redox reaction at the electrode surface. ► The electronic transmission in NiO could be more efficient to enhance the capacitive current response.