Octahedral V2O5 derived Au-decorated disordered rock salt as high-rate and long-life anode materials for Lithium-ion storage

Abstract

V2O5 is a kind of promising electrode material in Li-ion batteries because of its low cost, high specific capacity, and abundant resources, and it can convert into several LixV2O5 phases during the initial Li-insertion progress. Depending on the electrochemical activity of V2O5 at a low voltage region, a disordered rock salt (LixV2O5) anode is synthesized by the electrochemical in-situ methods. Nevertheless, the low electronic conductivity and electrochemical performance limit its utilization. Herein, Au is employed as an additive to enhance the Li-storage performance of LixV2O5. The electrochemical performances of V2O5 and V2O5/Au composites are systematically investigated; compared with V2O5, V2O5/Au composite possesses excellent initial discharging and charging capacities of 2, 572.8/395.6 mAh g−1, and after 4, 000 cycles, a reversible discharging and charging specific capacity of 229.8/229.5 mAh g−1 could be remained at the current density of 0.5 A g−1. More interestingly, V2O5/Au composite shows a high-rate capacity of 114.7 mAh g−1 even at 5.0 A g−1 after 10, 000 cycles. The electrode kinetic studies demonstrate that Au can enhance the electronic conductivity of V2O5, the initial discharging and CV curves reveal the phase inversion mechanisms of V2O5/Au composites during initial discharging progress. These data provide a fire-new method to enhance the electrochemical properties of LixV2O5.