Hierarchical CuCo2O4@nickel-cobalt hydroxides core/shell nanoarchitectures for high-performance hybrid supercapacitors

Abstract

Ni_0.5Co_0.5(OH)₂ nanosheets coated CuCo₂O₄ nanoneedles arrays were successfully designed and synthesized on carbon fabric. The core/shell nanoarchitectures directly served as the binder-free electrode with a superior capacity of 295.6mAhg^-1 at 1Ag^-1, which still maintained 220mAhg^-1 even at the high current density of 40Ag^-1, manifesting their enormous potential in hybrid supercapacitor devices. The as-assembled CuCo₂O₄@Ni_0.5Co_0.5(OH)₂//AC hybrid supercapacitor device exhibited favorable properties with the specific capacitance as high as 90Fg^-1 at 1Ag^-1 and the high energy density of 32Whkg^-1 at the power density of 800Wkg^-1. Furthermore, the as-assembled device also delivered excellent cycling performance (retaining 91.9% of the initial capacitance after 12,000 cycles at 8Ag^-1) and robust mechanical stability and flexibility, implying the huge potential of present hierarchical electrodes in energy storage devices.

Keywords: Electrodeposition; Hybrid supercapacitors; Hydrothermal method; Nickel-cobalt hydroxides; Spinel CuCo(2)O(4).