Facile synthesis of flexible and binder-free dandelion flower-like CuNiO₂ nanostructures as advanced electrode material for high-performance supercapacitors

Hierarchical CuNiO₂ nanospheres composed of large number of spikes, which look like a dandelion flower-like morphologies are grown on nickel foam via a facile and low-cost hydrothermal technique. These CuNiO₂ electrodes are used as an efficient electrode material for supercapacitor without using any binders or conducting polymer additives. The structural, composition and morphological behaviors of the CuNiO₂ electrodes are characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy methods. The CuNiO₂ nanoarchitectures provide the abundant active sites, high conductivity and rapid charge transport, which resulting the low-charge transfer resistance at the interface of electrode–electrolyte. Cyclic voltammetry and galvanostatic charge–discharge plateaus from the CuNiO₂ electrode exhibit the Faradic battery-type redox behavior, which is distinct form the profiles of carbon based materials. As a battery-type electrode, the dandelion flower-like CuNiO₂ nanoarchitectures exhibits the outstanding electrochemical performances with a high specific capacity (∼111.52 mA h g⁻¹ at 2 A g⁻¹), superb rate capability (∼81.4% retains even at 10 A g⁻¹), and excellent cycling life (∼89.13% at 6 A g⁻¹ over 3000 cycles), respectively. Therefore, with the above findings, CuNiO₂ material has remarkable application potential in supercapacitors and could be effectively applied in other energy storage technologies.