Core-shell assembly of Co3O4@NiO-ZnO nanoarrays as battery-type electrode for high-performance supercapattery

Core-shell Co3O4@NiO-ZnO nanocomposite arrays are successfully fabricated by annealing metal-organic framework assisted precursors, and investigated as binder-free battery-type electrodes for supercapacitor with a remarkably enhanced performance. The Co3O4@NiO-ZnO electrode delivers ultrahigh areal capacitance/capacity (4678 mF cm-2/1965 C cm-2/302 C g-1 at current density of 2 mA cm-2) and excellent cycling stability (83% retention over 10,000 cycles), due to multiple advantages offered by the intriguing core-shell structure, such as large surface area, fast electrolyte penetration, efficient charge transport, highly exposed active sites, and the synergistic effect between them. Moreover, an assembled supercapattery using Co3O4@NiO-ZnO arrays as positive electrode and active carbon as negative electrode yields a high energy density of 162 μWh cm-2 at a high power density of 1.676 mW cm-2 and superior capacitance retention of 93% over 10,000 cycles. These excellent results indicate that this efficient strategy can extend to prepare core-shell-type multi-metallic oxides arrays for high-performance supercapattery.