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Title: Elucidating the Solvation Structure and Dynamics of Lithium Polysulfides Resulting from Competitive Salt and Solvent Interactions

Abstract

Fundamental molecular level understanding of functional properties of liquid solutions provides an important basis for designing optimized electrolytes for numerous applica-tions. In particular, exhaustive knowledge of solvation structure, stability and transport properties is critical for developing stable electrolytes for fast charging and high energy density next-generation energy storage systems. Here we report the correlation between solubility, solvation structure and translational dynamics of a lithium salt (Li-TFSI) and polysulfides species using well-benchmarked classical molecular dynamics simulations combined with nuclear magnetic resonance (NMR). It is observed that the polysulfide chain length has a significant effect on the ion-ion and ion-solvent interaction as well as on the diffusion coefficient of the ionic species in solution. In particular, extensive cluster formation is observed in lower order poly-sulfides (Sx2-; x≤4), whereas the longer polysulfides (Sx2-; x>4) show high solubility and slow dynamics in the solu-tion. It is observed that optimal solvent/salt ratio is essen-tial to control the solubility and conductivity as the addi-tion of Li salt increases the solubility but decreases the mo-bility of the ionic species. This work provides a coupled theoretical and experimental study of bulk solvation struc-ture and transport properties of multi-component electro-lyte systems, yielding design metrics for developing optimal electrolytes withmore » improved stability and solubility.« less

Authors:
ORCiD logo; ORCiD logo; ; ; ; ; ; ORCiD logo; ORCiD logo;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1361977
Report Number(s):
PNNL-SA-125254
Journal ID: ISSN 0897-4756; 49376; KC0208010
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Chemistry of Materials; Journal Volume: 29; Journal Issue: 8
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Environmental Molecular Sciences Laboratory

Citation Formats

Rajput, Nav Nidhi, Murugesan, Vijayakumar, Shin, Yongwoo, Han, Kee Sung, Lau, Kah Chun, Chen, Junzheng, Liu, Jun, Curtiss, Larry A., Mueller, Karl T., and Persson, Kristin A. Elucidating the Solvation Structure and Dynamics of Lithium Polysulfides Resulting from Competitive Salt and Solvent Interactions. United States: N. p., 2017. Web. doi:10.1021/acs.chemmater.7b00068.
Rajput, Nav Nidhi, Murugesan, Vijayakumar, Shin, Yongwoo, Han, Kee Sung, Lau, Kah Chun, Chen, Junzheng, Liu, Jun, Curtiss, Larry A., Mueller, Karl T., & Persson, Kristin A. Elucidating the Solvation Structure and Dynamics of Lithium Polysulfides Resulting from Competitive Salt and Solvent Interactions. United States. doi:10.1021/acs.chemmater.7b00068.
Rajput, Nav Nidhi, Murugesan, Vijayakumar, Shin, Yongwoo, Han, Kee Sung, Lau, Kah Chun, Chen, Junzheng, Liu, Jun, Curtiss, Larry A., Mueller, Karl T., and Persson, Kristin A. Mon . "Elucidating the Solvation Structure and Dynamics of Lithium Polysulfides Resulting from Competitive Salt and Solvent Interactions". United States. doi:10.1021/acs.chemmater.7b00068.
@article{osti_1361977,
title = {Elucidating the Solvation Structure and Dynamics of Lithium Polysulfides Resulting from Competitive Salt and Solvent Interactions},
author = {Rajput, Nav Nidhi and Murugesan, Vijayakumar and Shin, Yongwoo and Han, Kee Sung and Lau, Kah Chun and Chen, Junzheng and Liu, Jun and Curtiss, Larry A. and Mueller, Karl T. and Persson, Kristin A.},
abstractNote = {Fundamental molecular level understanding of functional properties of liquid solutions provides an important basis for designing optimized electrolytes for numerous applica-tions. In particular, exhaustive knowledge of solvation structure, stability and transport properties is critical for developing stable electrolytes for fast charging and high energy density next-generation energy storage systems. Here we report the correlation between solubility, solvation structure and translational dynamics of a lithium salt (Li-TFSI) and polysulfides species using well-benchmarked classical molecular dynamics simulations combined with nuclear magnetic resonance (NMR). It is observed that the polysulfide chain length has a significant effect on the ion-ion and ion-solvent interaction as well as on the diffusion coefficient of the ionic species in solution. In particular, extensive cluster formation is observed in lower order poly-sulfides (Sx2-; x≤4), whereas the longer polysulfides (Sx2-; x>4) show high solubility and slow dynamics in the solu-tion. It is observed that optimal solvent/salt ratio is essen-tial to control the solubility and conductivity as the addi-tion of Li salt increases the solubility but decreases the mo-bility of the ionic species. This work provides a coupled theoretical and experimental study of bulk solvation struc-ture and transport properties of multi-component electro-lyte systems, yielding design metrics for developing optimal electrolytes with improved stability and solubility.},
doi = {10.1021/acs.chemmater.7b00068},
journal = {Chemistry of Materials},
number = 8,
volume = 29,
place = {United States},
year = {Mon Apr 10 00:00:00 EDT 2017},
month = {Mon Apr 10 00:00:00 EDT 2017}
}