Proton-Induced Defect-Rich Vanadium Oxides as Reversible Polysulfide Conversion Sites for High-Performance Lithium Sulfur Batteries

Lithium-sulfur (Li-S) batteries have attracted attention due to their high theoretical energy density, natural abundance, and low cost. However, the diffusion of polysulfides decreases the utilization and further degrades the battery's life. We have successfully fabricated a defect-rich layered sodium vanadium oxide with proton doping (HNVO) nanobelt and used it as the functional interface layer on the separator in Li-S batteries. Benefiting from the abundant defects of NVO and the catalytic activity of metal vanadium in the electrochemical process, the shuttle of polysulfides was greatly decreased by reversible chemical adsorption. Moreover, the extra graphene layer contributes to accelerating the charge carrier at high current densities. Therefore, a Li-S battery with G@HNVO delivers a high capacity of 1494.8 mAh g^-1 at 0.2 C and a superior cycling stability over 700 cycles at 1 C. This work provides an effective strategy for designing the electrode/separator interface layer to achieve high-performance Li-S batteries.