Details

Autor(en) / Beteiligte

• Xie, Shuai
• Chen, Xingjia
• Wang, Chao
• Lu, Yin‐Rui
• Chan, Ting‐Shan
• Chuang, Cheng‐Hao
• Zhang, Jing
• Yan, Wensheng
• Jin, Song
• Jin, Hongchang
• Wu, Xiaojun
• Ji, Hengxing

Titel

Role of the Metal Atom in a Carbon‐Based Single‐Atom Electrocatalyst for LiS Redox Reactions

Ist Teil von

• Small (Weinheim an der Bergstrasse, Germany), 2022-05, Vol.18 (18), p.e2200395-n/a

Ort / Verlag

Germany: Wiley Subscription Services, Inc

Erscheinungsjahr

2022

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• Carbon‐based single metal atom catalysts (SACs) are being extensively investigated to improve the kinetics of the Li–S redox reaction, which is greatly important for batteries with cell‐level energy densities >500 W h kg‐1. However, there are contradictory reports regarding the electrocatalytic activities of the different metal atoms and the role of the metal atom in LiS 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 LiS redox reactions. This study thus provides a fundamental understanding of how metal atoms in SACs impact LiS redox behavior and offers new guidelines to develop highly active catalytic materials for high‐performance LiS batteries. The critical role of single metal atoms is elucidated in LiS redox reactions. The coordination geometry and oxidation state of metal atoms strongly depend on the metal‐sulfur interaction. A moderate metal‐sulfur interaction, arising from the moderate hybridization of metal 3d and S p orbitals with the Fermi‐level crossing the metal 3d band, is more favorable for LiS redox reactions.