Two-Step Synthesis of Cobalt Oxide Nanowires via Electroless Deposition and Thermal Oxidation for Supercapacitor Applications

Abstract

Cobalt (Co) nanowires were synthesized via electroless deposition in ethylene glycol under an external magnetic field then oxidized in air via thermal oxidation at 250 to 300 °C. The nanowires have lengths in the range of 10 to 14 µm while the diameter increases with oxidation temperature. This can be attributed to the partial melting of the nanowires during oxidation, resulting to sintering. The peaks in the XRD patterns show complete oxidation of Co nanowires, producing a mixture of Co3O4 and CoO. It was observed that Co3O4 and CoO peaks were more intense at 270 °C. There is a decrease in specific capacitance (F/g) with increase in scan rate due to poor electron exchange between active material electrode and electrolyte. Highest calculated specific capacitance was 339.28 F/g using nanowires oxidized at 270 °C at 1 mV/s scan rate.