Hydrogenated V₂O₅ nanosheets for superior lithium storage properties

V₂O₅ is a promising cathode material for lithium ion batteries boasting a large energy density due to its high capacity as well as abundant source and low cost. However, the poor chemical diffusion of Li⁺, low conductivity, and poor cycling stability limit its practical application. Herein, oxygen-deficient V₂O₅ nanosheets prepared by hydrogenation at 200 °C with superior lithium storage properties are described. The hydrogenated V₂O₅ (H-V₂O₅) nanosheets deliver an initial discharge capacity as high as 259 mAh g^-1 and it remains 55% when the current density is increased 20 times from 0.1 to 2 A g^-1. The H-V₂O₅ electrode has excellent cycling stability with only 0.05% capacity decay per cycle after stabilization. The effects of oxygen defects mainly at bridging O(II) sites on Li⁺ diffusion and overall electrochemical lithium storage performance are revealed. The results reveal here a simple and effective strategy to improve the capacity, rate capability, and cycling stability of V₂O₅ materials which have large potential in energy storage and conversion applications. Oxygen-deficient V₂O₅ nanosheets with pre-compressed stress are prepared by low-temperature hydrogenation. The H-V₂O₅ nanosheets possess superior electrochemical properties, such as high capacity, improved conductivity, reduced stress in Li⁺ insertion/depletion, and <0.05% decay per cycle after stabilization, as a result of the generation of the proper amount of oxygen defects at O(II) sites.