PNNL

Abstract

This article summarizes our most recent studies on improved Li+-intercalation properties in vanadium oxides by engineering the nanostructure and interlayer structure. The intercalation capacity and rate are enhanced by almost two orders of magnitude with appropriately fabricated nanostructures. Processing methods for single-crystal V2O5 nanorod arrays, V2O5·nH2O nanotube arrays, and Ni/V2O5·nH2O core/shell nanocable arrays are presented; the morphologies, structures, and growth mechanisms of these nanostructures are discussed. Electrochemical analysis demonstrates that the intercalation properties of all three types of nanostructure exhibit significantly enhanced storage capacity and rate performance compared to the film electrode of vanadium pentoxide. Addition of TiO2 to orthorhombic V2O5 is found to affect the crystallinity, microstructure, and possible interaction force between adjacent layers in V2O5, and subsequently leads to enhanced Li+-intercalation properties in V2O5. The amount of water intercalated in V2O5 is found to have a significant influence on the interlayer spacing and electrochemical performance of V2O5·nH2O. A systematic electrochemical study has demonstrated that the V2O5·0.3H2O film has the optimal water content and exhibits the best Li+-intercalation performance.