Electroless fabrication and supercapacitor performance of CNT@NiO-nanosheet composite nanotubes

Composite nanostructures consisting of porous NiO nanosheets on carbon nanotubes (CNTs) are fabricated using a facile and low-cost electroless plating method. The CNTs, modified by a polymer, are adopted as the template upon which porous Ni nanosheets are grown using electroless plating. This is followed by removal of the polymer layer and oxidation of the Ni by controlled thermal annealing. The effect of reductant concentration on the morphology of the NiO nanosheets is studied. The electrochemical characteristics of the nanostructures are measured using chronopotentiometry. Experimental measurements show that the NiO nanosheet covered CNT composite nanostructures exhibit a relatively high specific capacitance of 1177 F g^-1 at a discharge current density of 2 A g^-1, while retaining 89.2% of its initial capacitance at a current density of 2 A g^-1 after 1000 cycles.