Tertiary structure of cactus-like WO3 spheres self-assembled on Cu foil for supercapacitive electrode materials

WO3 microspheres film with a tertiary, textured and porous structure assembled of WO3 hierarchical nanorods has been directly prepared on Cu foil using a one-step hydrothermal method. The field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectrum, X-Ray Diffraction (XRD), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) are used to reveal the surface microtopography, crystal structure, elementary composition, valence state and formation mechanism of WO3 tertiary structure. Moreover, the electro-chemical properties and supercapacitive performances of WO3 microspheres film are also intensively investigated. The WO3 microspheres film has high specific capacitances of 485, 426, 372, 319 and 260 F g(-1) at unit currents of 0.5, 1, 2, 5 and 10 A g(-1) and exhibits good cycle stability (93% after 5000 cycles) and reversibility (98.5%), a lower charge transfer resistance (0.5 Omega) and high energy densities ranging from 21 to 17 W h kg(-1) corresponded to high power densities varied from 150 to 3000 W kg(-1). (C) 2017 Elsevier B.V. All rights reserved.