Promoting polysulfide conversion by V2O3 hollow sphere for enhanced lithium-sulfur battery

Lithium-sulfur battery is regarded as one of the most promising candidates for next-generation energy storage devices due to its high theoretical capacity and energy density, howbeit the shuttle effect and sluggish reaction kinetic behavior of solute polysulfides hamper its practical applications. Hence, the large pore volume and regular structure of synthetic V2O3 are harnessed to achieve a uniform encapsulated S-V2O3 composite via molten sulfur infusion approach, which were synthesized by a facile hydrothermal method and exhibited large pore volume and regular structure. In the prepared S-V2O3 composites, V2O3 not only inhibits the shuttle effect by trapping polysulfide in cathode, but also promotes the sluggish reaction via accelerating the phase conversion of polysulfide. Through the quantitative analysis of accelerating effect based on the cyclic voltammetry curves, the S-V2O3 cathode exhibited a faster polysulfide redox than that of S-C cathode. As a consequence, the S-V2O3 composites exhibited a reasonable high electrochemical performance with a capacity of 973 mAh g(-1) at 0.1 C and capacity reservation of 67.8% at 0.2 C after 160 cycles.