(662f) SnSe?@Mxene Coated Separators for Extended-Cycle Lithium-Sulfur Batteries

Lithium–sulfur batteries (LSBs) have garnered significant attention as a next-generation energy storage system due to their high theoretical energy density and cost-effectiveness. However, their commercialization is hindered by severe polysulfide shuttling, sluggish redox kinetics, and rapid capacity degradation. In this work, we design and synthesize a series of SnSe₂@MXene heterostructural separator coatings to overcome these critical challenges. The integration of SnSe₂ nanostructures with Ti₃C₂Tₓ MXene creates a multifunctional interface that promotes strong polysulfide adsorption, enhances catalytic activity for sulfur conversion, and improves electron/ion transport. This synergistic architecture effectively suppresses the shuttle effect and accelerates redox kinetics, leading to superior electrochemical performance. LSBs incorporating the SnSe₂@MXene coating achieve an initial discharge capacity of 1629 mAh g⁻¹ at 0.2C. Under high sulfur loading (5 mg cm⁻²) and lean electrolyte conditions, the cell with this composite coating maintains a stable capacity of 747 mAh g⁻¹ after 100 cycles, with nearly 100% Coulombic efficiency. Furthermore, the SnSe₂@MXene heterostructure demonstrates outstanding long-term cycling stability, maintaining nearly 100% Coulombic efficiency at 1C after 1000 cycles, highlighting its robust catalytic functionality and structural durability. These findings position SnSe₂@MXene as a highly efficient coating for LSBs, paving the way for practical applications in high-energy-density, long-cycle-life LSBs.