Nanostructured Vanadium Oxide Electrodes for Enhanced Lithium‐Ion Intercalation

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·n H₂O nanotube arrays, and Ni/V₂O₅·n H₂O 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·n H₂O. A systematic electrochemical study has demonstrated that the V₂O₅·0.3 H₂O film has the optimal water content and exhibits the best Li⁺‐intercalation performance.