Investigating the synergistic effects of NbCo-oxide composite electrodes in supercapacitor and water splitting applications via hydrothermal synthesis

A self-supported, binderless NbCo-oxide composite electrode was synthesized directly on a nickel foam (NF) substrate through a simple one-step hydrothermal process and utilized for energy storage and conversion applications. The optimized NbCo-oxide electrode displayed impressive energy storage capabilities, boasting an areal capacitance of 10.1 F/cm2 (equivalent to 9.10C/cm2), an energy density of 0.57 mWh/cm2, and a power density of 6.75 mW/cm2 at a 15 mA/cm2 current density. Furthermore, this electrode exhibited notable bifunctional activity, with low overpotentials of 217 mV for the hydrogen evolution reaction (HER) and 250 mV for the oxygen evolution reaction (OER) at a 10 mA/cm2 current density. The distinctive morphology, featuring rectangular blocks and plate-like microstructures, provided numerous exposed electro-active sites, facilitating efficient charge transfer, and enhancing overall electrochemical performance. The sturdy self-supporting structure on the NF substrate ensures remarkable stability, highlighting NbCo-composite materials' potential for energy storage and conversion.