Hierarchical Se-Ti 3 C 2 @CNTs Catalytic Network for High-Stability Li–S Batteries: Synergistic Polysulfide Anchoring and Conversion

The practical application of lithium–sulfur (Li–S) batteries is plagued by the polysulfide shuttle effect and sluggish redox kinetics. Herein, a high-temperature selenization strategy is proposed to construct a selenium-rich interface via reactions between surface functional groups and selenium sources, yielding a selenium-doped Ti 3 C 2 quantum dots composite with carbon nanotubes (Se-Ti 3 C 2 QDs@CNTs) as the cathode material. Microstructural characterizations confirm that Se doping modulates the QDs’ electronic structure to form polar active sites, reinforcing polysulfide anchoring. Kinetic analysis reveals that uniformly dispersed Se-Ti 3 C 2 QDs on the 3D carbon network form catalytic centers, which synergistically suppress the shuttle effect and accelerate the redox kinetics. Benefiting from the conductive CNT framework and rapid charge transfer of QDs, the composite achieves efficient sulfur utilization and stable cycling, providing an innovative route for high-performance Li–S battery design.