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Title: Effect of the Hydrofluoroether Cosolvent Structure in Acetonitrile-Based Solvate Electrolytes on the Li+ Solvation Structure and Li-S Battery Performance.

Abstract

We evaluate hydrofluoroether (HFE) cosolvents with varying degrees of fluorination in the acetonitrile-based solvate electrolyte to determine the effect of the HFE structure on the electrochemical performance of the Li-S battery. Solvates or sparingly solvating electrolytes are an interesting electrolyte choice for the Li-S battery due to their low polysulfide solubility. The solvate electrolyte with a stoichiometric ratio of LiTFSI salt in acetonitrile, (MeCN)(2)-LiTFSI, exhibits limited polysulfide solubility due to the high concentration of LiTFSI. We demonstrate that the addition of highly fluorinated HFEs to the solvate yields better capacity retention compared to that of less fluorinated HFE cosolvents. Raman and NMR spectroscopy coupled with ab initio molecular dynamics simulations show that HFEs exhibiting a higher degree of fluorination coordinate to Li+ at the expense of MeCN coordination, resulting in higher free MeCN content in solution. However, the polysulfide solubility remains low, and no crossover of polysulfides from the S cathode to the Li anode is observed.

Authors:
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Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science - Office of Basic Energy Sciences - Materials Sciences and Engineering Division; USDOE Office of Science (SC); USDOE Office of Science - Office of Basic Energy Sciences - Joint Center for Energy Storage Research (JCESR)
OSTI Identifier:
1420080
DOE Contract Number:
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: ACS Applied Materials and Interfaces; Journal Volume: 9; Journal Issue: 45
Country of Publication:
United States
Language:
English
Subject:
X-ray photoelectron spectroscopy; hydrofluoroether cosolvent; lithium-sulfur battery; solvate electrolyte; sparingly solvating electrolyte; variable-temperature NMR spectroscopy

Citation Formats

Shin, Minjeong, Wu, Heng-Liang, Narayanan, Badri, See, Kimberly A., Assary, Rajeev S., Zhu, Lingyang, Haasch, Richard T., Zhang, Shuo, Zhang, Zhengcheng, Curtiss, Larry A., and Gewirth, Andrew A. Effect of the Hydrofluoroether Cosolvent Structure in Acetonitrile-Based Solvate Electrolytes on the Li+ Solvation Structure and Li-S Battery Performance.. United States: N. p., 2017. Web. doi:10.1021/acsami.7b11566.
Shin, Minjeong, Wu, Heng-Liang, Narayanan, Badri, See, Kimberly A., Assary, Rajeev S., Zhu, Lingyang, Haasch, Richard T., Zhang, Shuo, Zhang, Zhengcheng, Curtiss, Larry A., & Gewirth, Andrew A. Effect of the Hydrofluoroether Cosolvent Structure in Acetonitrile-Based Solvate Electrolytes on the Li+ Solvation Structure and Li-S Battery Performance.. United States. doi:10.1021/acsami.7b11566.
Shin, Minjeong, Wu, Heng-Liang, Narayanan, Badri, See, Kimberly A., Assary, Rajeev S., Zhu, Lingyang, Haasch, Richard T., Zhang, Shuo, Zhang, Zhengcheng, Curtiss, Larry A., and Gewirth, Andrew A. Wed . "Effect of the Hydrofluoroether Cosolvent Structure in Acetonitrile-Based Solvate Electrolytes on the Li+ Solvation Structure and Li-S Battery Performance.". United States. doi:10.1021/acsami.7b11566.
@article{osti_1420080,
title = {Effect of the Hydrofluoroether Cosolvent Structure in Acetonitrile-Based Solvate Electrolytes on the Li+ Solvation Structure and Li-S Battery Performance.},
author = {Shin, Minjeong and Wu, Heng-Liang and Narayanan, Badri and See, Kimberly A. and Assary, Rajeev S. and Zhu, Lingyang and Haasch, Richard T. and Zhang, Shuo and Zhang, Zhengcheng and Curtiss, Larry A. and Gewirth, Andrew A.},
abstractNote = {We evaluate hydrofluoroether (HFE) cosolvents with varying degrees of fluorination in the acetonitrile-based solvate electrolyte to determine the effect of the HFE structure on the electrochemical performance of the Li-S battery. Solvates or sparingly solvating electrolytes are an interesting electrolyte choice for the Li-S battery due to their low polysulfide solubility. The solvate electrolyte with a stoichiometric ratio of LiTFSI salt in acetonitrile, (MeCN)(2)-LiTFSI, exhibits limited polysulfide solubility due to the high concentration of LiTFSI. We demonstrate that the addition of highly fluorinated HFEs to the solvate yields better capacity retention compared to that of less fluorinated HFE cosolvents. Raman and NMR spectroscopy coupled with ab initio molecular dynamics simulations show that HFEs exhibiting a higher degree of fluorination coordinate to Li+ at the expense of MeCN coordination, resulting in higher free MeCN content in solution. However, the polysulfide solubility remains low, and no crossover of polysulfides from the S cathode to the Li anode is observed.},
doi = {10.1021/acsami.7b11566},
journal = {ACS Applied Materials and Interfaces},
number = 45,
volume = 9,
place = {United States},
year = {Wed Nov 15 00:00:00 EST 2017},
month = {Wed Nov 15 00:00:00 EST 2017}
}