ZnO/Carbon nanowalls shell/core nanostructures as electrodes for supercapacitors

In this work, carbon nanowalls (CNW) were coated with zinc oxide (ZnO) for use as supercapacitor electrodes. The ZnO layers of different thicknesses were deposited using pulsed laser ablation in oxygen reactive atmosphere. The performance of the CNW-ZnO electrodes was found to be dependent on the thickness of ZnO deposit, which in turn influences the specific capacitance and capacitance retention of the CNW-ZnO electrodes. The areal capacitance of the CNW-ZnO measured in mild electrolyte of 1 M KCl was as high as 4.3 mF·cm ⁻² at a current density of 0.2 mA·cm ⁻² and 1.41 mF·cm ⁻² at a scan rate of 10 mV·s ⁻¹ with an enhanced capacitance stability over 26,000 cycles. Such results demonstrate the potential use of ZnO nanostructures for low cost and high performance material for electrochemical capacitors.