Synthesis of V3O7 · H2O nanobelts as cathode materials for lithium–ion batteries

In this paper, we report a simple method to synthesize V3O7 · H2O nanobelts via hydrothermal treatment of commercial V2O5 powder at relatively low temperatures. The synthetic process is free of any templates and reducing agents. The influences of reaction time and temperature on the morphologies of the resulting products have been investigated. The products were characterized by X-ray diffraction (XRD), X-ray photoelectron spectrometry (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and charge-discharge test. SEM and TEM analyses reveal that the products consist of a large quantity of belt-like nanostructures and the belts are 100–500 nm in width and several tens to several hundreds micrometers in length as well as about 20 nm in average thickness. The electrochemical test found that the nanobelts exhibited an initial high discharge specific capacity of 253.0 mAh/g in the potential range of 3.8–1.7 V and its stabilized capacity still remained 228.6 mAh/g after 50 cycles. All these results indicate that the resulting V3O7 · H2O nanobelts are promising cathode materials in lithium–ion batteries.