Rationally designed hierarchical ZnCo2O4/Ni(OH)2 nanostructures for high-performance pseudocapacitor electrodes

Hierarchical ZnCo2O4/Ni(OH)(2) nanostructures on Ni foam were rationally designed and successfully fabricated through a facile two-step growth method. The ZnCo2O4 nanowires grown on Ni foam served as backbones to improve the electrical conductivity of redox active Ni(OH)(2) electrode materials, enhance the surface areas of electrode materials, and solidify the Ni(OH)(2) electrode materials onto Ni foam as a current collector. Ni(OH)(2) nanosheets were electro-deposited on ZnCo2O4 nanowires. The electrochemical performances of the hierarchical ZnCo2O4/Ni(OH)(2) nanostructures were measured. Their specific capacitance is 2826 F g(-1) at a current density of 2 mA cm(-2), the rate capability is 71.4% when the current density increases from 2 to 20 mA cm(-2), the cycling stability is 72% after 2000 cycles at a high current density of 10 mA cm(-2), and the high specific energy density is 166.7 W h kg(-1) at a current density of 2 mA cm(-2) in a two-electrode system.