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 Co 3 O 4 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 Co 3 O 4 nanostructures in conjunction with various electrochemical measurements. The major contribution of this study was focused on the development of an asymmetric supercapacitor using Co 3 O 4 nanostructures. The oxygen evolution reaction (OER) activity of Co 3 O 4 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 Co 3 O 4 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 Co 3 O 4 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 Co 3 O 4 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). The transformation of Co 3 O 4 nanowires into nanoparticles having large specific surface area were synthesized in the sugarcane molasses and their enhanced electrochemical performance was demonstrated. [Display omitted] • Sugarcane molasses was used to synthesize functional Co 3 O 4 nanostructures. • Electrochemical performance of Co 3 O 4 nanostructures was highly improved. • An overpotential of 330 mV was noticed at 10 mAcm−2 during water oxidation. • Asymmetric supercapacitor exhibited specific capacity of 310C/g. [ABSTRACT FROM AUTHOR]