Composite Nanoarchitectonics for Ternary Systems of Reduced Graphene Oxide/Carbon Nanotubes/Nickel Oxide with Enhanced Electrochemical Capacitor Performance

Abstract

Ternary nanocomposite composed of nickel oxide (NiO), multi-walled carbon nanotubes (CNTs), and reduced graphene oxide (RGO) was synthesized based on concept of nanoarchitectonics. During the solvothermal process, graphite oxide was reduced to RGO with concurrent uniform deposition of NiO nanoparticles on the surface of the RGO nanosheets and CNTs. Scanning and transmission electron microscopy observations revealed the uniform distribution of spherical NiO nanocrystals (average size 35 nm) on the CNTs and RGO. The electrochemical performances of NiO and the RGO/CNT/NiO ternary nanocomposite were evaluated by using cyclic voltammetry and chronopotentiometry techniques. A maximum specific capacitance of 367 F g−1 was achieved for the ternary nanocomposite at a current density of 1 A g−1 in 6 M KOH electrolyte, which is about 2.2 times greater than that of pristine NiO demonstrating a strong synergistic effect in this RGO/CNT/NiO ternary nanocomposite. Additionally, the ternary nanocomposite electrode showed excellent cycling stability retaining 94 % of the initial capacity after 1,000 cycles.