Facile preparation of a highly efficient NiZn2O4–NiO nanoflower composite grown on Ni foam as an advanced battery-type electrode material for high-performance electrochemical supercapacitors

Abstract

The development of combined simple metal oxides and binary metal oxides on a flexible conductor has been needed as a novel approach for energy storage sources. Here, we demonstrate a simple and versatile strategy towards the synthesis of a NiZn₂O₄–NiO nanoflower array (NFA) composite effectively deposited into a nickel (Ni) foam conductor for energy storing applications to achieve better electrochemical results. The morphology and other physical properties of the as-developed composite were analyzed, and the results suggest that the NiO nanoparticles have been effectively anchored into the binary NiZn₂O₄ nanoleaves array surface. The composite NiZn₂O₄–NiO NFAs nanoarchitecture combines superior surface area with huge numbers of active sites to boost electrochemical reactions and excellent transport between electrons and ions, as compared to NiZn₂O₄ nanoleaf arrays (NLAs). Meanwhile, taking into consideration electrochemical studies, the composite NiZn₂O₄–NiO NFAs exhibited extraordinary faradaic redox progress, which was different from the metal oxide based electrode profiles. Cyclic voltammetry and galvanostatic charge–discharge plateaus from the NiZn₂O₄ NLAs and NiZn₂O₄–NiO NFAs electrodes exhibit faradaic battery-type redox behavior, which is distinct from the profiles of carbon-based materials. As a battery-type electrode, the composite NiZn₂O₄–NiO NFAs electrode exhibited a greater supercapacitor activity with a higher specific capacitance of 482.7 C g⁻¹ at 1 A g⁻¹ and also yielded the best life-span with up to 98.14% capacity retained after 5000 cycles (vs. 253.4 C g⁻¹ at 1 A g⁻¹ and 91.4% retention of capacity after 5000 cycles for NiZn₂O₄ NLAs), which was the best result or comparable to recently reported composites of simple metal oxides/binary metal oxides-based electrode materials. Thus, with the above findings, the battery-type NiZn₂O₄–NiO NFAs electrode material has remarkable application potential and could be effectively applied in other energy storage technologies.