Guiding Sulfur Conversion Toward Favored Speciation via Fe Single Atom/Cluster Synergistic Catalysis in Lithium Sulfur Batteries

ABSTRACT Single‐atom catalysts (SACs), featuring nearly 100% atomic utilization efficiency, show great potential for application in Li–S batteries. However, the kinetic mismatch between the uniform active sites of SACs and the diverse reaction intermediates in the multi‑step sulfur redox process leads to a lack of catalytic specificity, causing suboptimal efficiency and activity degradation. In this work, a synergistic catalyst of Fe single atoms coupled with Fe clusters anchored on porous carbon nanofibers (Fe SA/ACs/CNF) was developed to address these constraints concurrently. The synergistic sites optimize the electron‐transfer pathway with LiPSs, which accelerates LiPSs conversion kinetics and lowers the associated reaction barriers, thereby promoting the formation of more stable sulfur phases (α‐S 8 ) and rapid deposition of Li 2 S. Arising from this mechanism, the sulfur cathode achieves an areal capacity of 5.9 mAh cm −2 under even a low E/S ratio of 5 µL mg −1 and sulfur loading of 6.5 mg cm −2 . This work establishes atomic/cluster synergy as an effective design paradigm for high‐efficiency sulfur catalysis, providing a pathway toward high‐performance Li–S batteries.