The influence of nanostructure size on V2O5 electrochemical properties as cathode materials for lithium ion batteries

In this paper, V2O5 nanostructures with a size depending on the annealing temperature are successfully synthesized by a sol-gel method. The crystal structure and morphology of the samples are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), selected area electron diffraction (SEAD) and scanning electron microscopy (SEM), respectively. Electrochemical testing such as discharge-charge cycling (CD) and cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) are employed in evaluating their electrochemical properties as cathode materials for lithium ion batteries. One-dimensional nanostructures are successfully synthesized with the same structure, composition and similar shape. The results reveal that for one-dimensional nanostructures, next to the thickness which must be as small as possible, the length of the nanocrystals is crucial and should be above 2 mm. The longer nanostructures obtained at 650 degrees C deliver a discharge specific capacity of 281 mA h g(-1) at a current rate of C/5 which is over 95.5% of the theoretical capacity for two Li+ ion intercalation (294 mA h g(-1)) within a voltage window of 2.0-4.0 V.