Synergistic vanadium carbide/oxide heterostructures within layered carbon for enhanced lithium–sulfur battery performance

Lithium–sulfur (Li–S) batteries hold great promise due to their high theoretical energy density, but their practical application is impeded by the insulating nature of sulfur and the shuttle effect of soluble lithium polysulfides. Herein, we report the synthesis of vanadium carbide/oxide heterostructures embedded in a two-dimensional carbon matrix (VC/V₂O₃@C) through a facile topological transformation strategy to address these challenges. The synergistic heterostructure combines strong polysulfide adsorption capability with excellent redox activity. In situ Raman spectroscopy reveals that the VC/V₂O₃@C composite significantly accelerates polysulfide conversion and suppresses the shuttle effect. As a result, Li–S batteries utilizing VC/V₂O₃@C exhibit a high discharge specific capacity of 1281  mAh g⁻¹ at 0.5 C and excellent cycling stability with a low capacity decay rate of 0.045 % per cycle (1200 cycles) at 1 C. Even under high sulfur loading and lean electrolyte conditions, impressive areal capacities are achieved. This work demonstrates a novel approach to enhancing Li–S battery performance through synergistic heterostructure design.