Interspersing Partially Oxidized V₂C Nanosheets and Carbon Nanotubes toward Multifunctional Polysulfide Barriers for...

Lithium-sulfur (Li-S) batteries have attracted much attention attributed to their high theoretical energy density, whereas the parasitic shuttling behavior of lithium polysulfides (LiPS) hinders this technology from yielding practically competitive performance. Targeting this critical challenge, we develop an advanced polysulfide barrier by modifying the conventional separator with CNTs-interspersed V₂C/V₂O₅ nanosheets to alleviate the shuttle effect. The partial oxidization of V₂C MXene constructs the V₂C/V₂O₅ composite with V₂O₅ nanoparticles uniformly dispersed on few-layered V₂C nanosheets, which synergistically and concurrently improves the sulfur confinement and redox reaction kinetics. Moreover, the interstacking between the 1D CNTs and the 2D V₂C/V₂O₅ not only prevents the agglomeration of nanosheets for efficient exposure of active interfaces but also constructs a robust conductive network for fast charge and mass transfers. The Li-S cells with V₂C/V₂O₅/CNTs-modified separator realize a high initial capacity (1240.4 mAh g^-1 at 0.2 C), decent capacity retention (82.6% over 500 cycles), and favorable areal capacity (5.9 mAh cm^-2) at a raised sulfur loading (6.0 mg cm^-2). This work affords a unique multifunctional separator design toward durable and efficient sulfur electrochemistry, holding great promise for improving the electrochemical properties of Li-S batteries.