Operando Spectromicroscopy of Sulfur Species in Lithium-Sulfur Batteries. Issue 1 (3rd November 2017)

• Record Type: Journal Article
• Authors: Miller, Elizabeth C.; Kasse, Robert M.; Heath, Khloe N.; Perdue, Brian R.; Toney, Michael F.
• Is Part Of: Journal of the Electrochemical Society. Volume 165:Issue 1(2018)
• Page Start: A6043
• Page End: A6050
• Publication Date: 2017-11-03
• Subjects: Lithium-Sulfur Batteries -- X-ray Absorption Spectroscopy -- X-ray Spectromicroscopy; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0091801jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : In this study, a novel cross-sectional battery cell was developed to characterize lithium-sulfur batteries using X-ray spectromicroscopy. Chemically sensitive X-ray maps were collected operando at energies relevant to the expected sulfur species and were used to correlate changes in sulfur species with electrochemistry. Significant changes in the sulfur/carbon composite electrode were observed from cycle to cycle including rearrangement of the elemental sulfur matrix and PEO10 LiTFSI binder. Polysulfide concentration and area of spatial diffusion increased with cycling, indicating that some polysulfide dissolution is irreversible, leading to polysulfide shuttle. Fitting of the maps using standard sulfur and polysulfide XANES spectra indicated that upon subsequent discharge/charge cycles, the initial sulfur concentration was not fully recovered; polysulfides and lithium sulfide remained at the cathodes with higher order polysulfides as the primary species in the region of interest. Quantification of the polysulfide concentration across the electrolyte and electrode interfaces shows that the polysulfide concentration before the first discharge and after the third charge is constant within the electrolyte, but while cycling, a significant increase in polysulfides and a gradient toward the lithium metal anode forms. This chemically and spatially sensitive characterization and analysis provides a foundation for further operando spectromicroscopy of lithium-sulfur batteries.