Dual‐Axial Nitrogen Coordination‐Induced Mn Charge Localization at Fe‐Mn Dual‐Atom Sites for Enhanced Sulfur Redox Kinetics
Guohua Liu, Guiqiang Cao, Ruixian Duan, Yitong Yuan, Mengyang Li, Chenyang Hou, Yifan Li, Zihao Yang, Jiaxuan Zuo, Lingkun Yang, Yukun Xi, Wenbin Li, Jingjing Wang, Xifei LiABSTRACT
The optimization of coordination environments for heteronuclear dual‐atom catalysts (DACs) has been a formidable challenge in lithium‐sulfur (Li‐S) batteries, arising from complex electronic coupling induced by inherent inter‐metallic‐site charge transfer at heteronuclear sites. Herein, an Fe‐Mn dual‐atom catalyst (FeMn‐(N ax ) 2 DAC/NC) with dual‐axial nitrogen coordination anchored on nitrogen‐doped carbon is rationally constructed to achieve the directional electronic modulation of active sites. The axial nitrogen ligand reconfigures the electronic distribution of Fe‐Mn heteronuclear sites, inducing Fe‐to‐Mn charge transfer and further charge localization on the Mn center. The electronic effect precisely modulates Mn d‐orbital energy levels, reinforcing the d‐p orbital hybridization between active sites and lithium polysulfides (LiPSs). The FeMn‐(N ax ) 2 DAC/NC strengthens the chemical adsorption of LiPSs to suppress the shuttle effect, and further bidirectionally accelerates the rate‐determining steps of sulfur redox: the solid‑to‑solid conversion from Li 2 S 2 to Li 2 S and the oxidative dissociation of Li 2 S. Consequently, the resultant sulfur cathodes deliver a discharge capacity of 682 mAh g − 1 at 5 C and an ultralow capacity decay rate of 0.047% per cycle over 1000 cycles at 3 C. This work offers a novel strategy for optimizing the redox kinetics of sulfur cathodes in Li‐S batteries.