Carbon-nanoparticles encapsulated in hollow nickel oxides for supercapacitor application

Monodisperse carbon nanoparticles encapsulated in hollow NiO nanostructures (C@NiO) have been successfully synthesized by calcination from a Ni(OH)(2) covered carbon (C@Ni(OH)(2)) precursor. The as-prepared products at each stage were extensively characterized and carefully discussed. The electrochemical properties of the carbon encapsulated in hollow NiO nanostructures were investigated using cycling voltammetry and charge-discharge techniques. The specific capacitance of the obtained C@NiO electrode was about 988.7 F g(-1) at a current density of 0.5 A g(-1). It shows better performance than hollow NiO spheres obtained in oxygen atmosphere. Furthermore, the C@NiO electrode shows a good capacitive retention of ca. 90.7% after 1000 charge-discharge cycles.