Hierarchical biomass-derived carbon framework with asymmetric ZnCo dual-atom pairs for synergistic polysulfide adsorption and catalysis in Lithium-sulfur batteries.

Lithium‑sulfur (LiS) batteries have recently attracted ever-increasing attention owing to their ultrahigh specific energy and substantial cost benefits of sulfur. However, the sluggish redox kinetics from the critical conversion of soluble long-chain lithium polysulfide to solid-state LiS remains a fundamental challenge. Herein, hierarchical porous nitrogen-doped carbon frameworks with asymmetric ZnCo dual-atom pairs (Zn-Co/NC) were successfully constructed using biomass-derived porous carbon as structural matrix through in situ growth and assisted pyrolysis strategy. The resulting hierarchical porous structure offers abundant electrochemically active interface and facilitates ultrafast electron/ion transport. In addition, the well-constructed ZnCo dual-atom pairs demonstrates strong adsorption and catalysis effect for sulfur species. Consequently, LiS cells incorporating Zn-Co/NC@PP deliver a 0.2C initial discharge capacity of 1263.5 mAh g, coupled with exceptional 500-cycle durability at 1C. Furthermore, when the battery is under the conditions of high sulfur loading (6.6 mg cm) and low electrolyte (E/S = 5.0 μL mg), a satisfying surface capacity of 4.9 mAh cm can still be achieved. Such a precise design of versatile dual-atom pairs catalysts involving synergistic adsorption and catalysis provides valuable insights for multistage sulfur conversion reactions.