Title: Understanding the Solvation Structure of Li-Ion Battery Electrolytes Using DFT-Based Computation and ¹ H NMR Spectroscopy

Abstract

Molecular dynamics (MD) simulations, density functional theory (DFT) calculations, and ¹H NMR spectroscopy were performed to gain a complementary understanding of the concentrated Li-ion electrolyte system, lithium bis(trifluoromethanesulfonyl)imide (Li[TFSI]) dissolved in tetraglyme. The computational methods provided the concentration dependence of differing solvation structure motifs by reference to changes in the corresponding NMR spectra. By combining both the computational and experimental methodologies, we show that the various solvation structures, dominated by the coordination between the tetraglyme (G4) solvent and lithium cation, directly influence the chemical shift separation of resonances in the ¹H NMR spectra of the solvent. Thus, the ¹H NMR spectra can be used to predict the fraction of tetraglyme involved in the solvation process, with quantitative agreement with solvation fraction predictions from MD simulation snapshots. Overall, our results demonstrate the reliability of a hybrid computational and experimental methodology to understand the solvation structure and hence transport mechanism of LiTFSI-G4 electrolytes in the low concentration region.

Authors:

Im, Julia  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-6633-2513"

Halat, David M.  ^[2];

• Search DOE PAGES for author "Halat, David M."
• Search DOE PAGES for ORCID "0000-0002-0919-1689"

Fang, Chao  ^[2];

• Search DOE PAGES for author "Fang, Chao"
• Search DOE PAGES for ORCID "0000-0002-6207-0819"

Hickson, Darby T.  ^[2];

• Search DOE PAGES for author "Hickson, Darby T."
• Search DOE PAGES for ORCID "0000-0002-5133-9755"

Wang, Rui  ^[2];

• Search DOE PAGES for author "Wang, Rui"
• Search DOE PAGES for ORCID "0000-0002-4058-9521"

Balsara, Nitash P.  ^[2];

• Search DOE PAGES for author "Balsara, Nitash P."
• Search DOE PAGES for ORCID "0000-0002-0106-5565"

Reimer, Jeffrey A.  ^[2]

• Search DOE PAGES for author "Reimer, Jeffrey A."
• Search DOE PAGES for ORCID "0000-0002-4191-3725"

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+ Show Author Affiliations

1. Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California94720, United States
2. Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California94720, United States, Materials Sciences Division and Joint Center for Energy Storage Research (JCESR), Lawrence Berkeley National Laboratory, Berkeley, California94720, United States

Publication Date:

Wed Nov 16 00:00:00 EST 2022

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); National Institutes of Health (NIH); National Science Foundation (NSF)

OSTI Identifier:

1898467

Alternate Identifier(s):

OSTI ID: 1987505

Grant/Contract Number:  

AC02-05CH11231; S10OD023532; 2018784

Resource Type:

Published Article

Journal Name:

Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry

Additional Journal Information:

Journal Name: Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry Journal Volume: 126 Journal Issue: 47; Journal ID: ISSN 1520-6106

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

25 ENERGY STORAGE; cations; electrolytes; molecules; solvation; solvents