Reagent induced formation of NiCo2O4 with different morphologies with large surface area for high performance asymmetric supercapacitors

A facile, robust and low cost hydrothermal method has been used to fabricate spinel-type NiCo2O4 nanosheets (NCNs) and nanoflakes (NCFs) using NaOH and oxalic acid as a precipitate agents. The structural, morphological and porosity properties of the electrodes were examined by X-ray diffraction (XRD), Raman, Field emission scanning electron microscope (FESEM), N-2 adsorption-desorption and X-ray photoelectron spectra (XPS) analysis. The NiCo2O4 nanoflakes electrode exhibit outstanding electrochemical actions with a specific capacitance reaching 1366 Fg(-1) at 2 Ag-1, as well as high capacitance retention (86.7%) after 5000 cycles at 20 Ag-1. Besides, the asymmetric supercapacitor (ASC) was made-up using NiCo2O4 nanoflakes and activated carbon (AC) as the positive and negative, respectively. The ASC device distribute an ultrahigh energy density of 42.1 Whkg(-1) at the power density of 1193 Wkg(-1), representing its admirable application potential as an electrode material for supercapacitors.