Electrochemically dispersed nickel oxide nanoparticles on multi-walled carbon nanotubes

It is the first report that the uniformly dispersed nickel oxide nanoparticles were synthesized on the substrates of multi-walled carbon nanotubes (MWNT) via electrochemical technique. The morphology and chemical state of the NiOx/MWNT composite were characterized using scanning electron microscopy and X-ray photoelectron spectroscopy. The electrochemical test results revealed that the surface-decorated composite with oxide particle sizes of 15–30 nm can deliver specific capacitance about 190 F g−1, ten-fold greater than that of pure MWNT. Meanwhile, the electrode displayed excellent cycling stability with nearly 100% coulombic efficiency over 1000 cycles and good rate capability with acceptable specific capacitance fading, indicating that this novel nanostructured composite electrode was a promising candidate for electrochemical capacitors.

► Nickel oxide nanoparticles were electrochemically dispersed on the exterior of MWNT. ► These nanoparticles enhance the specific capacitance of electrodes more than ten-fold. ► Nickel oxide particles dispersed reach specific capacitance ∼1250 F g−1. ► The composite electrodes exhibit excellent rate capability and cyclability.