Abstract:
In this work, a wet-chemical followed by thermal annealing
strategy is employed to prepare Ni0.5Cu0.5Co2O4 without using any template.
The material with flower-like architecture is composed of several nanorods that
exhibit good textural properties (surface area: 120 m2
/g, pore volume: 0.35 cc/g)
and exposed facets and thus offers numerous electroactive sites for ion
diffusion at the vicinity of electrode−electrolyte. The fabricated electrode with
Ni0.5Cu0.5Co2O4 exhibits a higher specific capacitance of 367.4 F/g compared
to fabricated electrodes using NiCo2O4 (280.3 F/g) and CuCo2O4(133.5 F/g)
at the current density of 1 A/g. The material also exhibits high electronic conductivity (low Rct) and impressive cycling stability (89% retention after 5000th
cycle). The combination of the synergistic effect of the variable oxidation state
of three metal ions, large electroactive surface area, and fast ion diffusion
through the porous structure are responsible for this high performance
supercapacitive property of the ternary metal oxide. An assembly of four
equivalent asymmetric supercapacitors (fabricated using activated carbon as cathode and Ni0.5Cu0.5Co2O4 as anode) connected
in series is demonstrated for powering LEDs. The fabricated device has been shown to achieve 53.08 W h kg−1 energy density at
the power density of 700.3 W kg−1 and withholding the columbic efficiency of 99.6% after a 5000 cyclic runs at 5 A/g applied
current density. Moreover, the output efficiency of the device is better or comparable to most of the Ni- and Co-based
asymmetric devices reported earlier.
