Analytical Detection of Polysulfides in the Presence of Adsorption Additives by Operando X-ray Absorption Spectroscopy

Abstract : A mechanism for Li–S battery operation with a composite electrode and an adsorption additive obtained by using operando ultraviolet/visible (UV/vis) spectroscopy and X-ray absorption spectroscopy confirms the role of the adsorption additive and reflects the conversion mechanism of sulfur into Li2S. Operando UV/vis spectroscopy shows a reversible appearance of the long-chain polysulfides in the separator in the fifth cycle, whereas the appearance of mid- and short-chain polysulfides suggests a polysulfide shuttle mechanism. By using a nonsulfur-containing electrolyte, a high-precision analysis of sulfur K-edge X-ray absorption near-edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS) spectra is possible. The XANES analysis shows that polysulfides reach the maximum concentration at the end of the high-voltage plateau, and the low-voltage plateau is characteristic of the polysulfides/Li2S equilibrium. The relative amount of Li2S increases linearly until the end of discharge and reaches a relative amount of 75%. This is confirmed by sulfur K-edge EXAFS analysis. Additionally, a quantitative analysis of EXAFS spectra measured during discharge evidences a decrease of the average S–S coordination number. This can be interpreted as a decrease of the chain length of polysulfides. EXAFS analysis showed that there are no specific interactions of the polysulfide species with the matrix or with other species in the electrolyte.
Document type :
Journal articles
Complete list of metadatas

https://hal.archives-ouvertes.fr/hal-01188769
Contributor : Lorenzo Stievano <>
Submitted on : Monday, August 31, 2015 - 2:55:26 PM
Last modification on : Tuesday, May 28, 2019 - 2:06:13 PM

Identifiers

Collections

Citation

Robert Dominko, Manu U. M. Patel, Vida Lapornik, Alen Vizintin, Matjaz Kozelj, et al.. Analytical Detection of Polysulfides in the Presence of Adsorption Additives by Operando X-ray Absorption Spectroscopy. Journal of Physical Chemistry C, American Chemical Society, 2015, 119 (33), pp.19001-19010. ⟨10.1021/acs.jpcc.5b05609⟩. ⟨hal-01188769⟩

Share

Metrics

Record views

255