Fabrication of flower-like bismuth vanadate hierarchical spheres for an improved supercapacitor efficiency

Abstract

A cost-effective and simple method has been developed for the preparation of flower-like hierarchical spheres of semiconductor oxide materials. Efficient self-assembly of BiVO₄ flower-like hierarchical spheres was performed via a simple hydrothermal method, followed by calcination at 500 °C. X-ray diffraction (XRD) studies distinguished diffraction planes of the monoclinic BiVO₄ phase, which was further confirmed by field emission scanning electron microscopy (FESEM) analysis. The electronic and optical properties of BiVO₄ were studied via X-ray photoelectron spectroscopy (XPS) and UV-visible spectroscopy. XPS analysis confirmed the binding energy relations and the formation of BiVO₄, and also an increase in the Bi–O, V–O bond strengths in BiVO₄. The remarkable efficiency of pseudocapacitor electrode materials depends on the consistent fabrication of nano architectures. The carbon-free BiVO₄ electrodes showed a higher specific capacitance of 1203 F g⁻¹ at 2 A g⁻¹, without detectable degradation after 2000 cycles and a beneficial cycling stability was achieved because of the electrochemical activity of the distinctive porous hierarchical architecture. Our synthetic method suggests a simple procedure for the design and fabrication of bismuth vanadate hierarchical nano architectures, encouraging electrochemical energy storage. These nanocomposites could be utilized as anode materials in lithium-ion batteries.