Growth of highly mesoporous CuCo2O4 nanoflakes@Ni(OH)2 nanosheets as advanced electrodes for high-performance hybrid supercapacitors

Abstract

In this work, we report a simple method to fabricate the hierarchical three-dimensional CuCo2O4@Ni(OH)2 hybrid nanostructures on Ni foam for supercapacitors. The highly mesoporous and interconnected CuCo2O4 nanoflakes are ideal scaffolds for loading electroactive Ni(OH)2 shell nanosheets, which significantly boost the energy storage efficiency of the integrated system. The optimized CuCo2O4@Ni(OH)2 hybrid electrode delivers a high areal capacity of 439 μAh/cm2 at 2 mA/cm2 and a good rate capability of 82.7% at 80 mA/cm2. In light of these merits, a hybrid supercapacitor (HSC) has been further assembled. The HSC device displays simultaneously high energy and power densities (48 Wh/kg at 468 W/kg, and 34 Wh/kg at 9145 W/kg), as well as good long-term cycling stability. After charging for a short time, two HSC devices connected in series can drive LEDs with different colors efficiently, suggesting the great potential of this hybrid material toward practical applications as advanced electrodes for high-performance HSC devices.