Double-Shelled Nanocapsules of V2O5-Based Composites as High-Performance Anode and Cathode Materials for Li Ion Batteries

Abstract

Double-shelled nanocapsules of V₂O₅−SnO₂ composites were chemically assembled via a one-pot solution method. These hollow nanocapsules are composed of a double-shelled V₂O₅ matrix that includes a low weight ratio of SnO₂ (e.g., 10 or 15%). In these double shells, open-structured V₂O₅ acts as not only a supporting matrix but also an active electrode component. The gap between the two shells and the hollow cavity provide sufficient space for volume variation during conversion reactions and lithium alloying/dealloying processes. As a promising anode electrode, this nanocomposite shows a large, reversible capacity of 947 mA h g⁻¹ at a rate of 250 mA g⁻¹ and retains a high capacity of 673 mA h g⁻¹ after 50 cycles. Even at a high rate of 2500 mA g⁻¹, the current nanocomposite electrode can still deliver a reversible capacity of 505 mA h g⁻¹. As a cathode electrode, our nanocomposite shows not only a high reversible capacity of ∼250 mA h g⁻¹ but also good cycling and rate capability.