Double-shelled nanocapsules of V2O5-based composites as high-performance anode and cathode materials for Li ion batteries

Abstract

(Graph Presented) Double-shelled nanocapsules of V2O 5-SnO2 composites were chemically assembled via a onepot solution method. These hollow nanocapsules are composed of a double-shelled V2O5 matrix that includes a low weight ratio of SnO 2 (e.g., 10 or 15%). In these double shells, open-structured V 2O5 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. © 2009 American Chemical Society.