A high-energy sulfur cathode in carbonate electrolyte by eliminating polysulfides via solid-phase lithium-sulfur transformation

• Published in: Nature communications Vol. 9; no. 1; pp. 4509 - 10
• Main Authors: Li, Xia, Banis, Mohammad, Lushington, Andrew, Yang, Xiaofei, Sun, Qian, Zhao, Yang, Liu, Changqi, Li, Qizheng, Wang, Biqiong, Xiao, Wei, Wang, Changhong, Li, Minsi, Liang, Jianwen, Li, Ruying, Hu, Yongfeng, Goncharova, Lyudmila, Zhang, Huamin, Sham, Tsun-Kong, Sun, Xueliang
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 30-10-2018; Nature Publishing Group; Nature Portfolio
• Subjects: 140/133; 140/58; 147/135; 639/4077/4079/891; 639/766/930/12; Cathodes; Electrochemical analysis; Electrochemistry; Electrolytes; Electrolytic cells; Humanities and Social Sciences; Lithium; Lithium sulfur batteries; multidisciplinary; Phase transitions; Polysulfides; Reaction mechanisms; Science; Science (multidisciplinary); Solid phases; Spectroscopy; Sulfur; Sulfur content; X ray absorption; X ray spectra
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-06877-9

Carbonate-based electrolytes demonstrate safe and stable electrochemical performance in lithium-sulfur batteries. However, only a few types of sulfur cathodes with low loadings can be employed and the underlying electrochemical mechanism of lithium-sulfur batteries with carbonate-based electrolytes is not well understood. Here, we employ in operando X-ray absorption near edge spectroscopy to shed light on a solid-phase lithium-sulfur reaction mechanism in carbonate electrolyte systems in which sulfur directly transfers to Li
2
S without the formation of linear polysulfides. Based on this, we demonstrate the cyclability of conventional cyclo-S
8
based sulfur cathodes in carbonate-based electrolyte across a wide temperature range, from −20 °C to 55 °C. Remarkably, the developed sulfur cathode architecture has high sulfur content (>65 wt%) with an areal loading of 4.0 mg cm
−2
. This research demonstrates promising performance of lithium-sulfur pouch cells in a carbonate-based electrolyte, indicating potential application in the future.
Carbonate-based electrolytes can impart advantages in lithium sulfur batteries, but performance is often limited by incompatibility with sulfur-based cathodes. Here the authors elucidate a mechanism for conversion of sulfur to lithium sulfide and demonstrate improved performance in a Li-S cell.