Hierarchical Al-doped and Hydrogenated ZnO Nanowire@MnO2 Ultra-Thin Nanosheet Core/Shell Arrays for High-Performance Supercapacitor Electrode

Abstract

[email protected] and Al-doped ZnO (AZO)@MnO2 hybrid electrodes in core/shell geometries have been synthesized on stainless steel substrates by a scalable low-cost solution route. Cyclic voltammogram (CV) and galvanostatic (GV) charge-discharge measurements demonstrated that the [email protected] hybrid electrode exhibited superior capacitive properties, in 1M Na2SO4 aqueous solution, to the [email protected] electrode. The specific capacitance based on total electrode mass is estimated to be 275 F/g at a current density of 2 A/g. The [email protected] electrode also displays an excellent long-term cyclic stability at a current density of 10 A/g with less than 3% loss after 2000 charge-discharge cycles. A ~35% capacity retention was observed at 60A/g, which is over 400% specific capacitance increment compared with the [email protected] electrode. The superior electrochemical capacitive properties of the [email protected] over [email protected] can be attributed to the enhanced electrical conductivity in the core nanowire, as a result of Al doping and hydrogenation. The low cost fabrication combined with the excellent capacitive properties indicates that the [email protected] hybrid architecture can serve as a promising electrode material for supercapacitors as well as other electrochemical energy storage/conversion devices.