M–N3 Configuration Single-Atom Catalysts for High-Performance Na–S Batteries: Insights from DFT and Data-Assisted Analysis

The sluggish redox kinetics of polysulfide conversion remain a major bottleneck in sodium–sulfur (Na–S) batteries. Single-atom catalysts anchored on boron nitride substrates (M–N3@BN) offer promising routes to accelerate polysulfide conversion due to their high atomic efficiency and tunable electronic structures. However, the rational identification of highly active metal centers remains challenging due to the complex relationship between intermediate adsorption and catalytic activity. Herein, we develop a DFT-guided data-assisted strategy to systematically screen and design M–N3@BN single-atom catalysts for efficient sulfur conversion. By analyzing the adsorption characteristics of Na2Sn intermediates and the corresponding energy evolution during multistep sulfur conversion, potential catalytic candidates are identified and further evaluated through first-principles calculations. This systematic analysis reveals the critical electronic factors governing catalytic activity and provides insights into the regulation of intermediate adsorption and reaction kinetics. Among the investigated candidates, Fe–N3@BN and Zn–N3@BN are revealed as highly active catalysts, exhibiting reduced Na2S2 → Na2S conversion barriers of 0.48 and 0.24 eV, respectively. Electronic structure analyses indicate that the M–N3 active center, with optimized intermediate binding and strong d–p orbital hybridization near the Fermi level, enables superior catalytic kinetics. This work reveals the electronic principles governing polysulfide conversion and provides guidance for the rational design of single-atom catalysts for Na–S batteries.