Three-dimensional Co3O4@NiO hierarchical nanowire arrays for solid-state symmetric supercapacitor with enhanced electrochemical performances

In this article, a highly ordered three-dimensional (3D) Co3O4@NiO hierarchical nanowire arrays supported on nickel foam is fabricated by a facile hydrothermal method. The morphologies evolution of Co3O4@NiO nanoarchitecture reaction times and growth temperature are investigated in detail. When investigated as binder-free electrodes for supercapacitors (SCs), such unique Co3O4@NiO core-shell hybrid electrodes exhibit ultrahigh specific capacitances, which are several times larger than the pristine Co3O4 electrode. Because of reduced charge transfer resistances of the core-shell structured composites, electron transfer capability is enhanced and the electrochemical performances are improved. This Co3O4@NiO core-shell nanostructures electrode exhibits an ultrahigh specific capacitance of 1236.67 F g(-1), and excellent cycling stability (5000 cycles) at a current density of 1 A g(-1). The symmetric supercapacitor shows significantly enhanced specific capacitances as high as 720.71 at 1 A g(-1). Moreover, the supercapacitor shows excellent cycling stability with 91.35% capacity retention over 5000 cycles at 1 A g(-1). (C) 2016 Published by Elsevier B.V.