Vanadium oxides nanostructures: Hydrothermal synthesis and electrochemical properties

• Vanadium oxides nanostructures were synthesized hydrothermally.
• Reversible redox behavior with doping/dedoping process.
• Doping/dedoping is easier for Li+ to Na+.
• Energy-related applications such as cathodes in lithium batteries.

A facile and template-free one-pot strategy is applied to synthesize nanostructured vanadium oxide particles via a hydrothermal methodology. X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transforms infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) have been used to characterize the structure and morphology of the samples. The products are gradually changed from sheet-shaped VO2(B) to rod-like V3O7·H2O with decreasing cyclohexanediol as both protective and reducing agent. The specific surface area of the VO2(B) nanosheets and V3O7·H2O nanorods was found to be 22 and 16 m2 g−1, respectively. Thin films of VO2(B) and V3O7·H2O deposited on ITO substrates were electrochemically characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The voltammograms show reversible redox behavior with doping/dedoping process corresponding to reversible cation intercalation/de-intercalation into the crystal lattice of the nanorods/nanosheets. This process is easier for the small Li+ cation than larger ones Na+.

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