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

Double-shelled nanocapsutes 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 similar to 250 mA h g(-1) but also good cycling and rate capability.