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

Abstract

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.