Streamline Sulfur Redox Reactions to Achieve Efficient Room‐Temperature Sodium–Sulfur Batteries

• Published in: Angewandte Chemie International Edition Vol. 61; no. 16; pp. e202200384 - n/a
• Main Authors: Lei, Yaojie, Wu, Can, Lu, Xinxin, Hua, Weibo, Li, Shaobo, Liang, Yaru, Liu, Hanwen, Lai, Wei‐Hong, Gu, Qinfeng, Cai, Xiaolan, Wang, Nana, Wang, Yun‐Xiao, Chou, Shu‐Lei, Liu, Hua‐Kun, Wang, Guoxiu, Dou, Shi‐Xue
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 11.04.2022
• Edition: International ed. in English
• Subjects: Batteries; Binding sites; Cathodes; Chains; Cobalt; Cobalt sulfide; Conversion; Cycles; Electron Reservoir; Electron Transfer; Electrons; Kinetics; Redox reactions; Reservoirs; Sodium; Sodium–Sulfur Batteries; Sulfur; Sodium-Sulfur Batteries; Electron Reservoir; Kinetics; Electron Transfer; Cobalt
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202200384

It is vital to dynamically regulate S activity to achieve efficient and stable room‐temperature sodium–sulfur (RT/Na−S) batteries. Herein, we report using cobalt sulfide as an electron reservoir to enhance the activity of sulfur cathodes, and simultaneously combining with cobalt single atoms as double‐end binding sites for a stable S conversion process. The rationally constructed CoS2 electron reservoir enables the straight reduction of S to short‐chain sodium polysulfides (Na2S4) via a streamlined redox path through electron transfer. Meanwhile, cobalt single atoms synergistically work with the electron reservoir to reinforce the streamlined redox path, which immobilize in situ formed long‐chain products and catalyze their conversion, thus realizing high S utilization and sustainable cycling stability. The as‐developed sulfur cathodes exhibit a superior rate performance of 443 mAh g−1 at 5 A g−1 with a high cycling capacity retention of 80 % after 5000 cycles at 5 A g−1. Engineering CoS2 as electron reservoirs overcomes the limited length of the electron diffusion tunnel over an insulating sulfur cathode and thus achieves fast reaction kinetics in sodium–sulfur batteries. With the assistance of Co1 single atoms, this strategy provides streamlined redox paths, which reduce the formation of unstable polysulfides and enable stable sodium–sulfur batteries.