MoO3 Nanostructured Electrodes Prepared via Hydrothermal Process for Lithium Ion Batteries

Abstract

We demonstrated the use of MoO3 nanostructure electrodes for lithium ion batteries, synthesized by the hydrothermal process with different concentrations of nitric acid. As the concentration of nitric acid increased, the electrodes showed phase transition from the metastable hexagonal MoO3 (h-MoO3) to the stable orthorhombic MoO3 (alpha-MoO3). The electrodes prepared in 0.1 and 1 M HNO3 exhibited rod-shaped h-MoO3 structures. However, the electrode prepared in 4 M HNO3 exhibited a mixed configuration of rod-shaped h-MoO3 and belt-type alpha-MoO3 structure. Finally, the electrode prepared in 5 M HNO3 displayed a complete transition to the belt-type alpha-MoO3 structure. The single-crystalline nature of alpha-MoO3 nanobelts prepared in 5.0 M HNO3 was clearly observed by field-emission transmission electron microscopy, demonstrating that the MoO3 nanobelts were also grown along the [001] direction. The single-crystalline alpha-MoO3 nanobelts showed improved charge capacity and high rate performance due to their relatively large specific surface area, low transport resistance, and the high lithium ion diffusion coefficient of the nanostructure electrode.