Boosting Polysulfide Redox Kinetics in Lithium–Sulfur Battery via V ₂ CT _<i>x</i> MXene/Porous Carbon Nanofiber Composite Interlayer

The practical application of lithium–sulfur batteries (LSBs) is hindered by the polysulfide shuttle effect and the sluggish sulfur redox kinetics. Herein, a multifunctional interlayer composed of V 2 CT x MXene and porous carbon nanofibers (PCNFs) is designed to suppress the shuttle effect and enhance the electrocatalytic performance. The formation of a heterostructure between the PCNFs and V 2 CT x enhances the interfacial electron mobility, resulting in improved charge‐transport properties and increased electrical conductivity. Furthermore, V 2 CT x exhibits superior sulfur‐reduction‐reaction catalytic activity, achieving high electrochemical reversibility for both the liquid–solid two‐phase conversion from long‐chain soluble Li 2 S x (4 ≤ x ≤ 8) and the solid‐state Li 2 S 2 to Li 2 S conversion. Various theoretical calculations corroborate these findings by elucidating the interfacial and catalytic mechanisms. The LSBs with the V 2 CT x /PCNF interlayer deliver a high initial discharge capacity of 1319.4 mAh g −1 at 0.1 C and retain a capacity of 707.5 mAh g −1 even at a high rate of 5 C, along with significantly enhanced cycling stability. This work not only proposes an approach to improve the electrochemical performance of LSBs but also provides new insights into the rational design of multifunctional interlayers for next‐generation energy storage systems.