Single atomic Co decorated mesoporous carbon/MXene heterostructure as redox promoters for high-stable Li-S battery

Lithium-sulfur (Li-S) batteries are considered a potential breakthrough in future energy storage systems owing to remarkable energy density. However, they are fundamentally constrained by practical obstacles including polysulfide shuttle effect and sluggish redox reaction kinetics. To address these challenges, single atomic Co decorated sandwich-like mesoporous carbon/MXene heterostructure (SACo-MC@MX) is designed by using a single-micelle-directed interfacial assembly strategy. This innovative catalytic heterostructure is endowed with combined physical adsorption and chemical anchoring capability toward effectively capturing lithium poly- sulfides, while simultaneously enhancing the redox reaction kinetics of sulfur species through Co atomic catalysis, as fully confirmed by comprehensive electrochemical characterizations and in-situ Raman. The cell employed with SACo-MC@MX achieves an impressive capacity of 1241.6 mAh g- 1 at 0.2C, an excellent rate capability up to 5C, and outstanding long-term cycling stability with a low decay rate of 0.030 % per cycle at 1C over 1000 cycles. Additionally, even with a high sulfur loading of 5.3 mg cm- 2, the cell retains a superior areal capacity of 4.64 mAh cm- 2 after 100 cycles, providing the possibility to commercialize Li-S batteries.