Orchestrating Site-Specific Redox Catalysis via Dual-Atom Engineering for Enhanced Polysulfide Conversion in High-Performance Li-S Batteries.

Lithium-sulfur (Li-S) batteries are significantly constrained by severe polysulfide shuttling and sluggish redox kinetics, primarily due to the challenge of concurrently modulating the sulfur reduction reaction (SRR) during discharge and the sulfur evolution reaction (SER) during charge. Addressing this issue necessitates the development of advanced electrocatalysts that can effectively decouple these distinct pathways while providing complementary active sites. Herein, we construct a site-specific Ni-Mo dual-atom catalyst via atomic-level engineering, in which the Ni and Mo centers are respectively tailored to promote the SRR and SER. Experimental characterizations and theoretical calculations reveal that Ni facilitates the liquid-to-solid conversion of lithium polysulfide, while Mo reduces the energy barrier for LiS decomposition. This dual-atom configuration not only retains the intrinsic activity of each metal but also enhances orbital coupling through localized electronic reconstruction, enabling coordinated and directional modulation of sulfur redox reactions. When applied in Li-S batteries, the Ni-Mo DAC delivers a high rate capacity (770.3 mAh g at 5.0C), minimal capacity fading (0.033% per cycle over 1000 cycles), and excellent stability under high sulfur loading and broad temperature conditions. This work offers a rational strategy for constructing redox-coordinated catalytic interfaces to resolve kinetic asymmetry in Li-S electrochemistry.