Nano MoO3 Phase Structural Evolution During Hydrothermal Synthesis and Its Electrochemical Properties

Micron rods of hexagonal MoO3 (h-MoO3) and nanobelts of orthorhombic MoO3 (alpha-MoO3) were prepared using a facile hydrothermal synthesis. The factors that influenced the morphologies, crystalline structures and electrochemical properties of the MoO3 were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The experimental revealed that both the reaction time and acidity coefficient played important roles in controlling the crystalline structure and morphology of the MoO3; however, the acidity coefficient was the crucial factor. At lower acidity coefficient, the growth of the MoO3 nucleus only resulted in well-crystallized h-MoO3 rods as the reaction time increased. As the acidity coefficient increased, the h-MoO3 phase was transformed into an alpha-MoO3 phase and the morphology changed gradually from three-dimensional hexagonal micron rods to low-dimension nanobelts. As the anode electrode, the alpha-MoO3 nanobelts exhibited better electrochemical properties. The initial specific capacities of 223.1 mAh center dot g(-1) and a wide discharge plateau of 2.2V for the alpha-MoO3 were obtained. On the other hand a stable electrochemical performance was achieved for h-MoO3 micron rods.