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 conducing 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 (similar to 111.52 mA h g(-1) at 2 A g(-1)), superb rate capability (similar to 81.4% retains even at 10 A g(-1)), and excellent cycling life (similar to 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.