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

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.