A composite electrode consisting of nickel hydroxide, carbon nanotubes, and reduced graphene oxide with an ultrahigh electrocapacitance

Abstract

A novel 3D nanostructure consisting of Ni(OH)2 nanoparticles, carbon nanotubes (CNTs), and reduced graphene oxide with an extremely high electrocapacitance is described. The nanostructure consists of CNTs with embedded Ni(OH)2 nanoparticles as pillars for reduced graphene oxide sheets. Electrochemical results show that the composite displays specific capacitances as high as 1235 and 780 F g-1 at current densities of 1 and of 20 A g-1, respectively. In addition, the composite retains 80% of its original capacity after 500 cycles at a discharge current density of 10 A g-1. This 3D pseudocapacitor electrode has a number of important features, such as fast ion and electron transfer, easy access ofpseudoactive species and efficient utilization, and excellent reversibility of Ni(OH) 2 nanoparticles. © 2012 Elsevier B.V. All rights reserved.