Size Controlled Nickel Oxide Nanoparticles on Carbon Nanotubes for Supercapacitor Electrode

We have synthesized supercapacitor electrodes fashioned of NiOx/multiwalled carbon nanotubes (MWNTs), in which the controlled NiOx nanoparticles were prepared via a simple colloidal method and supported on the MWNTs. The sizes of the NiOx nanoparticles on MWNTs were systematically varied from 4 to 14 nm at a fixed metal loading of 20 wt% by changing sintering temperature in a controlled manner. The maximum specific capacitance of the NiOx/MWNTs was measured to be ca. 215 F per unit gram of NiOx/MWNTs by cyclic voltammetry (CV) in an aqueous 1 M KOH electrolyte, demonstrating that the specific capacitance of the MWNTs-supported nanosize NiOx is strongly dependent on the dispersion and size of the nanoparticles for the supercapacitor performance.