Role of the Metal Atom in a Carbon‐Based Single‐Atom Electrocatalyst for LiS Redox Reactions
Shuai Xie, Xingjia Chen, Chao Wang, Yin‐Rui Lu, Ting‐Shan Chan, Cheng‐Hao Chuang, Jing Zhang, Wensheng Yan, Song Jin, Hongchang Jin, Xiaojun Wu, Hengxing Ji
Abstract
. However, there are contradictory reports regarding the electrocatalytic activities of the different metal atoms and the role of the metal atom in LiS chemistry still remains unclear. This is due to the complex relationship between the catalytic behavior and the structure of carbon-based SACs. Here, the catalytic behavior and active-site geometry, oxidation state, and the electronic structure of different metal centers (Fe/Co/Ni) embedded in nitrogen-doped graphene, and having similar physicochemical characteristics, are studied. Combining X-ray absorption spectroscopy, density functional theory calculations, and electrochemical analysis, it is revealed that the coordination-geometry and oxidation state of the metal atoms are modified when interacting with sulfur species. This interaction is strongly dependent on the hybridization of metal 3d and S p-orbitals. A moderate hybridization with the Fermi level crossing the metal 3d band is more favorable for LiS redox reactions. This study thus provides a fundamental understanding of how metal atoms in SACs impact LiS redox behavior and offers new guidelines to develop highly active catalytic materials for high-performance LiS batteries.