A topochemically constructed flexible heterogeneous vanadium-based electrocatalyst for boosted conversion kinetics of polysulfides in Li–S batteries

Abstract

Lithium–sulfur batteries (LSBs) are considered as one of the most promising next-generation high-energy rechargeable batteries due to their ultrahigh energy density and low cost, however, their practical application has been severely hindered due to the rigorous shuttle effect of soluble polysulfides and sluggish reaction kinetics. Here, a novel flexible 3D nitrogen-doped graphene supported V₂O₃/VN heterogeneous host was constructed by a facile topochemical nitridation strategy. Such unique architecture endowed the V₂O₃ with strong adsorption activity and the highly conductive VN with superior catalytic capability, synergistically promotes the redox kinetics and effectively restrains the shuttle effect of polysulfides. Impressively, the designed V₂O₃@VN-20 electrode exhibited a high reversible capacity of 1130 mA h g⁻¹ and 980 mA h g⁻¹ at 1C and 2C respectively, and maintained long-term cyclability with a low capacity decay of 0.1% per cycle after 300 cycles at 5C. More importantly, the heterostructured electrode still retained a high capacity of 862 mA h g⁻¹ with a high sulfur loading of 5 mg cm⁻² after 100 cycles at 0.5C. Our work might provide a general approach for guiding the rational design of heterostructured materials with multifunctionality towards high-energy flexible Li–S batteries.