Enhanced asymmetric supercapacitor and oxygen evolution reaction performance by sugarcane molasses-generated Co₃O₄ nanostructures

A sugarcane molasses, a promising source of polysaccharides, was used in this study in order to modify the size, shape orientation, surface area, and charge transport properties of Co₃O₄ nanostructures. Several methods have been used to obtain structural information on nanostructures, including powder X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible spectrometry, and Fourier transform infrared spectroscopy (FTIR). Furthermore, cyclic voltage measurements (CV), linear sweep voltage measurements (LSV), galvanostatic charge-discharge measurements (GCD), and electrochemical impedance measurements (EIS) were performed on Co₃O₄ nanostructures in conjunction with various electrochemical measurements. The major contribution of this study was focused on the development of an asymmetric supercapacitor using Co₃O₄ nanostructures. The oxygen evolution reaction (OER) activity of Co₃O₄ nanostructures was investigated in an aqueous solution containing 1 M KOH, and an asymmetric supercapacitor was tested in an electrolyte containing 3 M KOH. An optimal Co₃O₄ nanostructure with OER activity has an overpotential of 330 mV at 10 mA cm⁻² and a Tafel slope of 92 mVdec⁻¹. The optimized Co₃O₄ nanostructure demonstrated excellent durability during OER activity for 40 h. Among the three electrode-based supercapacitors, sample 1 had the highest specific capacity with 1070C/g, the highest capacitive retention percentage at 100%, and the highest columbic efficiency at 101%. Thus, ASC devices based on optimized Co₃O₄ nanostructures exhibit exceptional specific capacities of 301C/g and 6.4 Wh/Kg at 1.5A/g. The retained capacitance was observed to be 99% after 40000 galvanostatic charge-discharge cycles (GCD).