Porous Cobalt Oxide@Layered Double Hydroxide Core-Shell Architectures on Nickel Foam as Electrode for Supercapacitor

Abstract

The high performance of an electrode relies largely on a scrupulous design of nanoarchitectures and smart hybridization of electroactive materials. A porous core-shell architecture in which one-dimensional cobalt oxide (Co3O4) nanowire cores are grown on nickel foam prior to the growth of layered double hydroxide (LDH) shells is fabricated. Hydrothermal precipitation and thermal treatment result in homogeneous forests of 70-nm diameter Co3O4 nanowire, which are wrapped in LDH-nanosheet-built porous covers through a liquid phase deposition method. Due to the unique core-shell architecture and the synergetic effects of Co3O4 and NiAl-LDH, the obtained Co3O4@LDH electrode exhibits a capacitance of 1 133.3 F/g at a current density of 2 A/g and 688.8 F/g at 20 A/g (5.3 F/cm2 at 9.4 mA/cm2 and 3.2 F/cm2 at 94 mA/cm2), which are better than those of the individual Co3O4 nanowire. Moreover, the electrode shows excellent cycling performance with a retention rate of 90.4% after 3 000 cycles at a current density of 20 A/g.