Nickel oxide on directly grown carbon nanofibers for energy storage applications

Abstract

Nickel oxide on directly grown carbon nanofibers (CNF-NiO) electrodes were fabricated and used as cathodes for hydrogen production by water electrolysis and as electrode materials for supercapacitors. Tafel polarization from the CNF-NiO electrodes showed an improvement in the hydrogen evolution reaction. This was attributed to the increment of the electrochemically active surface area, conductivity, and the synergy effects between the nickel oxide, carbon nanofibers, and nickel foam substrate. When used for supercapacitor applications, these electrodes showed a specific capacitance of ca. 776.20 ± 26 mF cm−2 at a current density 3 mA cm−2. These electrodes prepared using a facile method also exhibited a capacitance retention of 89% even after 3000 cycles with a coulombic efficiency of 89% when cycled at 20 mA cm−2. Considering the simplistic approach of the electrode preparation, the stability, and the capacitance, this method opens an avenue to try various metal oxide deposit on the directly grown CNF template.