Vanadium dioxide- reduced graphene oxide binary host as an efficient polysulfide plague for highperformance lithium- sulfur batteries

Lithium-sulfur batteries are strongly expected to be the next-generation energy storage technology due to their superior theoretical specific capacity and energy density. However, the low conductivity of sulfur and the discharge species (Li2S2, Li2S), the shuttle issue of soluble intermediates, and the large volume change hinder their further practical application. In this study, vanadium dioxide (VO2) was successfully grown on reduced graphene oxide (rGO) surface via a one-step rapid and facile solvothermal method, and named as the VO2@rGO binary host. In this structure, the VO2 nanoflakes displayed intensive chemical adsorption for polar lithium polysulfide species (LiPSs), accelerating the conversion of long-chain LiPSs to Li2S2/Li2S discharge products and thus suppressing the shuttling of soluble LiPSs. Additionally, rGO could ensure good electronic conductivity of the sulfur cathode and significantly enhanced the electrochemical reaction kinetics. Particularly, the VO2@rGO/S cathode demonstrated a high initial discharge capacity of 1358 mA h g(-1) at 0.2C and retained a stable cycling performance with a reversible capacity of 1049 mA h g(-1) over 370 cycles (low capacity decay of 0.06% per cycle). Such excellent performance revealed its good potential for use in advanced lithium-sulfur batteries.