Dual‐Functional Phosphorus‐Doped Iron Single‐Atom Catalyst on Reduced Graphene Oxide for Efficient Lithium–Sulfur Batteries: Simultaneous Polysulfides Trapping/Catalysis and Lithium Deposition Regulation

The development of high-performance lithium-sulfur (Li-S) batteries is hindered by the complex interplay of lithium polysulfides (LiPSs) shuttle effects and uncontrolled lithium dendrite growth. Herein, we introduce a dual-functional-phosphorus-doped iron single-atom catalysts on reduced graphene oxide (Fe-NPC@rGO)-to address both issues. Density functional theory (DFT) and experiments reveal that Fe-NPC@rGO enhances sulfur redox kinetics and regulates lithium deposition. The Fe-NPC high charge density and enhanced electron transfer (vs. Fe-N4) enable Fe-NPC@rGO to trap polysulfides (LiPSs) and boost their conversion, reducing shuttle effects. Simultaneously, its lithiophilic properties enable uniform Li plating, inhibiting dendrites. Li-S cells with Fe-NPC@GO modified separators deliver a high discharge capacity of 1156 mAh g-1 at 1 C, with an exceptionally low-capacity decay of 0.032% per cycle over 1000 cycles. Moreover, full Li-S battery configuration (Fe-NPC@rGO-Li||Fe-NPC@rGO-PP||ROCNT-S) achieves high areal capacity of 4.9 mAh cm-2 at 5 mg cm-2 sulfur loading, low electrolyte to sulfur (E/S) ratio of 6 µL mg-1, and an ultralow negative to positive (N/P) ratio of 1.2. These findings provide valuable insights into the structural optimization of electrocatalysts and underscore the significant potential of Fe-NPC@rGO in advancing the electrochemical performance of next-generation Li-S batteries.