V2O5 quantum dots/graphene hybrid nanocomposite with stable cyclability for advanced lithium batteries

Abstract

High-speed electron transfer channels and short Li ion transport distance are beneficial to improvement of Li ion battery properties. Here, a two-step solution phase synthesis method is developed to construct the V2O5 quantum dots/graphene hybrid nanocomposite by controlling nucleation and growth processes. It is demonstrated that the V2O5 quantum dots with an average size of 2-3 nm are uniformly anchored on the graphene sheets. The specific capacity can achieve 212mAhg−1 at 100mAg−1 after 100 cycles. Significantly, the novel V2O5 quantum dots/graphene shows a stable cycling performance with 89% capacity retention after 300 cycles. The improvement in electrochemical properties could be attributed to the short Li ion transfer distance, two-dimensional electron channels, homogeneous dispersion and immobilization of V2O5 quantum dots. Meanwhile, it indicates that V2O5 quantum dots/graphene is promising cathode material for use in long-life rechargeable lithium batteries. This design conception and synthesis strategy for V2O5 could also be extended to other electrode material systems.