Design and fabrication of cobaltx nickel(1-x) telluride microfibers on nickel foam for battery-type supercapacitor and oxygen evolution reaction study

Abstract

Tellurium (Te) is a metal with the ability to function as a self-sacrificing template and exhibits strong chemical reactivity with counter metals. By the simple inward diffusion of metal ions on its surface, it can form long one-dimensional architect. Utilizing this, a one-dimensional cobaltx nickel(1-x) telluride (CoxNi(1-x)Te) microfibers (MFs) on nickel foam substrate has been constructed for a bifunctional electrode application. The theoretical and experimental investigations on the CoxNi(1-x)Te validates the Co0.75Ni0.25Te superiority over other ratios. The synergistically caused effects at 3:1 Co/Ni ratio reactivity with Te enhance the microstructure bifunctional electrode property with excellent stability during long cycle operation. The density functional theory calculations of Co0.75 Ni0.25Te revealed a better quantum capacitance due to the increased density of states near Fermi levels and achieved the enhanced oxygen evolution reaction activity because of increasing OH coverage. The assembled device Co0.75Ni0.25Te MF//activated carbon achieves outstanding energy storage performance with a maximum energy density of 50.8 Wh/Kg (58.4 μWh/cm2) at a power density of 672.7 W/Kg (773.5 μW/cm2) and sustains the performance up to 10,000 cycles, with a capacity retention of 90.1%. As an electrocatalyst, Co0.75Ni0.25Te MF/nickel foam requires a low overpotential (η) of 289 mV to reach a current density (j) of 10 mA/cm2 in 0.1 M KOH for oxygen evolution reaction.