Cation-Directed Selective Polysulfide Stabilization in Alkali Metal-Sulfur Batteries

Qingli Zou, Zhuojian Liang, Guan Ying Du, Chi You Liu, Elise Y. Li, Yi Chun Lu*

*此作品的通信作者

研究成果: 雜誌貢獻期刊論文同行評審

70 引文 斯高帕斯(Scopus)

摘要

Alkali metal sulfur redox chemistry offers promising potential for high-energy-density energy storage. Fundamental understanding of alkali metal sulfur redox reactions is the prerequisite for rational designs of electrode and electrolyte. Here, we revealed a strong impact of alkali metal cation (Li+, Na+, K+, and Rb+) on polysulfide (PS) stability, redox reversibility, and solid product passivation. We employed operando UV-vis spectroscopy to show that strongly negatively charged short-chain PS (e.g., S4 2-/S3 2-) is more stabilized in the electrolyte with larger cation (e.g., Rb+) than that with the smaller cation (e.g., Li+), which is attributed to a stronger cation-anion electrostatic interaction between Rb+ and S4 2-/S3 2- owing to its weaker solvation energy. In contrast, Li+ is much more strongly solvated by solvent and thus exhibits a weaker electrostatic interaction with S4 2-/S3 2-. The stabilization of short-chain PS in K+-, Rb+-sulfur cells promotes the reduction of long-chain PS to short-chain PS, leading to high discharge potential. However, it discourages the oxidation of short-chain PS to long-chain PS, leading to poor charge reversibility. Our work directly probes alkali metal-sulfur redox chemistry in operando and provides critical insights into alkali metal sulfur reaction mechanism.

原文英語
頁(從 - 到)10740-10748
頁數9
期刊Journal of the American Chemical Society
140
發行號34
DOIs
出版狀態已發佈 - 2018 8月 29

ASJC Scopus subject areas

  • 催化
  • 一般化學
  • 生物化學
  • 膠體和表面化學

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