Title: The Interplay between Salt Association and the Dielectric Properties of Low Permittivity Electrolytes: The Case of LiPF₆ and LiAsF₆ in Dimethyl Carbonate

Abstract

Here, we present evidence that the dielectric constant of an electrolyte solution can be effectively used to infer the association regime of the salt species from computational methods. As case studies, we consider the low dielectric constant solvent dimethyl carbonate with LiAsF₆ and LiPF₆ salts at low concentrations. Using both quantum “ab initio” methods as well classical molecular dynamics simulations, we elucidate the salt’s contribution to the dielectric constant as well as the dipolar relaxation times, which act as quantitative signatures. By comparing to previously published measurements, we provide strong evidence for the presence of contact-ion pairs at these low concentrations. Interestingly, these ion pairs increase the dielectric constant of the solution, allowing for significantly improved ionic conductivity as a function of salt concentrations. We also discuss the role of multimeric equilibrium species as contributors to the functional properties of designer electrolytes, such as dielectric properties of the solution and ionic conductivity.

Authors:

Self, Julian  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-5486-9559"

Wood, Brandon M. ^[2]; Rajput, Nav Nidhi  ^[3];

• Search DOE PAGES for author "Rajput, Nav Nidhi"
• Search DOE PAGES for ORCID "0000-0003-4740-8217"

Persson, Kristin A. ^[4]

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+ Show Author Affiliations

1. Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Engineering; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Technologies Area
2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Technologies Area; Univ. of California, Berkeley, CA (United States). Dept. of Applied Science and Technology
3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Technologies Area
4. Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Engineering, and Dept. of Applied Science and Technology; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Technologies Area

Publication Date:

Wed Dec 20 00:00:00 EST 2017

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1483679

Grant/Contract Number:  

AC02-06CH11357; AC02-05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Physical Chemistry. C

Additional Journal Information:

Journal Volume: 122; Journal Issue: 4; Journal ID: ISSN 1932-7447

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY