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

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(Co_3O_4)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 Co_3O_4 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 Co_3O_4and NiAl-LDH,the obtained Co_3O_4@LDH electrode exhibits a capacitance of 1 133.3F/g at a current density of 2A/g and 688.8F/g at 20A/g(5.3F/cm^(2 )at 9.4mA/cm^(2 )and 3.2F/cm^(2 )at 94mA/cm^2),which are better than those of the individual Co_3O_4nanowire.Moreover,the electrode shows excellent cycling performance with a retention rate of 90.4%after 3 000cycles at a current density of 20A/g.

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 Co3O 4 nanowire, which are wrapped in LDH-nanosheet-built porous coversthrough a liquid phase deposition method. Due to the unique core-shell architecture and the synergetic effects of Co3O4 and NiAl-LDH, the obtained Co3O 4@LDH electrode exhibits a capacitance of 1 133.3 F/g at acurrent density of 2 A/g and 688.8 F/g at 20 A/g （5.3 F/cm 2 at 9.4 mA/cm 2 and 3.2 F/cm 2 at 94 mA/cm 2）, which are better than those of the individual Co 3O 4 nanowire. Moreover, the electrode shows excellent cycling prformance with a retention rate of 90.4% after 3 000 cycles at a current density of 20 A/g.