Ether-compatible sulfurized polyacrylonitrile cathode with excellent performance enabled by fast kinetics via selenium doping

• Published in: Nature communications Vol. 10; no. 1; p. 1021
• Main Authors: Chen, Xin, Peng, Linfeng, Wang, Lihui, Yang, Jiaqiang, Hao, Zhangxiang, Xiang, Jingwei, Yuan, Kai, Huang, Yunhui, Shan, Bin, Yuan, Lixia, Xie, Jia
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 04.03.2019; Nature Publishing Group; Nature Portfolio
• Subjects: 140/133; 140/146; 140/58; 147/135; 147/143; 147/28; 639/638/161/886; 639/638/161/891; Cathodes; Conversion; Decay rate; Dissolution; Electrochemical analysis; Electrochemistry; Electrolytes; Humanities and Social Sciences; Kinetics; Lithium; Lithium sulfur batteries; multidisciplinary; Polyacrylonitrile; Reaction kinetics; Science; Science (multidisciplinary); Selenium; Sulfur
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-08818-6

Sulfurized polyacrylonitrile is suggested to contain S n ( n  ≤ 4) and shows good electrochemical performance in carbonate electrolytes for lithium sulfur batteries. However inferior results in ether electrolytes suggest that high solubility of Li 2 S n ( n  ≤ 4) trumps the limited redox conversion, leading to dissolution and shuttling. Here, we introduce a small amount of selenium in sulfurized polyacrylonitrile to accelerate the redox conversion, delivering excellent performance in both carbonate and ether electrolytes, including high reversible capacity (1300 mA h g −1 at 0.2 A g −1 ), 84% active material utilization and high rate (capacity up to 900 mA h g −1 at 10 A g −1 ). These cathodes can undergo 800 cycles with nearly 100% Coulombic efficiency and ultralow 0.029% capacity decay per cycle. Polysulfide dissolution is successfully suppressed by enhanced reaction kinetics. This work demonstrates an ether compatible sulfur cathode involving intermediate Li 2 S n ( n  ≤ 4), attractive rate and cycling performance, and a promising solution towards applicable lithium-sulfur batteries. Lithium sulfur batteries are promising for advanced energy storage, but polysulfide shuttling limits performance lifetime. Here the authors report selenium-doping in a sulfur-based cathode to prevent dissolution of polysulfide intermediates, leading to ether compatibility, high capacity and stable cycling.