Formation of nanoporous nickel oxides for supercapacitors prepared by electrodeposition with hydrogen evolution reaction and electrochemical dealloying

Highly nanoporous nickel oxide electrodes were obtained by electrodeposition accompanied by hydrogen evolution reaction and the selective electrochemical dealloying of copper from Ni-(Cu) porous foam. The nanoporous nickel oxide electrodes consequently have numerous dendritic morphologies composed of nanopores with 20-30 nm diameters. The specific capacitances were 428 F g(-1) for as-deposited Ni-(Cu) foam electrode and 1,305 F g(-1) for nanoporous nickel-oxide electrode after dealloying process, respectively. This indicates increased surface area by dealloying process leads to innovative increase of specific capacitance.