skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Complex Ion Dynamics in Carbonate Lithium-Ion Battery Electrolytes

Abstract

Li-ion battery performance is strongly influenced by ionic conductivity, which depends on the mobility of the Li ions in solution, and is related to their solvation structure. In this work, we have performed first-principles molecular dynamics (FPMD) simulations of a LiPF6 salt solvated in different Li-ion battery organic electrolytes. We employ an analytical method using relative angles from successive time intervals to characterize complex ionic motion in multiple dimensions from our FPMD simulations. We find different characteristics of ionic motion on different time scales. We find that the Li ion exhibits a strong caging effect due to its strong solvation structure, while the counterion, PF6– undergoes more Brownian-like motion. Lastly, our results show that ionic motion can be far from purely diffusive and provide a quantitative characterization of the microscopic motion of ions over different time scales.

Authors:
 [1];  [1];  [2];  [1];  [2];  [1]; ORCiD logo [1];  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Univ. of Utah, Salt Lake City, UT (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1375301
Report Number(s):
LLNL-JRNL-674755
Journal ID: ISSN 1932-7447
Grant/Contract Number:
AC52-07NA27344
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 121; Journal Issue: 12; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY

Citation Formats

Ong, Mitchell T., Bhatia, Harsh, Gyulassy, Attila G., Draeger, Erik W., Pascucci, Valerio, Bremer, Peer -Timo, Lordi, Vincenzo, and Pask, John E. Complex Ion Dynamics in Carbonate Lithium-Ion Battery Electrolytes. United States: N. p., 2017. Web. doi:10.1021/acs.jpcc.7b02006.
Ong, Mitchell T., Bhatia, Harsh, Gyulassy, Attila G., Draeger, Erik W., Pascucci, Valerio, Bremer, Peer -Timo, Lordi, Vincenzo, & Pask, John E. Complex Ion Dynamics in Carbonate Lithium-Ion Battery Electrolytes. United States. doi:10.1021/acs.jpcc.7b02006.
Ong, Mitchell T., Bhatia, Harsh, Gyulassy, Attila G., Draeger, Erik W., Pascucci, Valerio, Bremer, Peer -Timo, Lordi, Vincenzo, and Pask, John E. Mon . "Complex Ion Dynamics in Carbonate Lithium-Ion Battery Electrolytes". United States. doi:10.1021/acs.jpcc.7b02006. https://www.osti.gov/servlets/purl/1375301.
@article{osti_1375301,
title = {Complex Ion Dynamics in Carbonate Lithium-Ion Battery Electrolytes},
author = {Ong, Mitchell T. and Bhatia, Harsh and Gyulassy, Attila G. and Draeger, Erik W. and Pascucci, Valerio and Bremer, Peer -Timo and Lordi, Vincenzo and Pask, John E.},
abstractNote = {Li-ion battery performance is strongly influenced by ionic conductivity, which depends on the mobility of the Li ions in solution, and is related to their solvation structure. In this work, we have performed first-principles molecular dynamics (FPMD) simulations of a LiPF6 salt solvated in different Li-ion battery organic electrolytes. We employ an analytical method using relative angles from successive time intervals to characterize complex ionic motion in multiple dimensions from our FPMD simulations. We find different characteristics of ionic motion on different time scales. We find that the Li ion exhibits a strong caging effect due to its strong solvation structure, while the counterion, PF6– undergoes more Brownian-like motion. Lastly, our results show that ionic motion can be far from purely diffusive and provide a quantitative characterization of the microscopic motion of ions over different time scales.},
doi = {10.1021/acs.jpcc.7b02006},
journal = {Journal of Physical Chemistry. C},
number = 12,
volume = 121,
place = {United States},
year = {Mon Mar 06 00:00:00 EST 2017},
month = {Mon Mar 06 00:00:00 EST 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 1work
Citation information provided by
Web of Science

Save / Share:
  • A conductivity study is carried out on lithium bis[1,2 benzenediolato (2-)-O,O{prime}]borate and on lithium bis[3-fluoro-1,2-benzenediolato(2-)-O,O{prime}]borate in dimethoxyethane and propylene carbonate from infinite dilution to saturation in the temperature range 228 < T (K) < 308. The electron-drawing fluorine substituent produces a decrease of the association constant by a factor of about three for PC-based solutions and 5.5 for solutions in dimethoxyethane. The increase in the maximum of conductivity by about 30% (propylene carbonate) and about 80% (dimethoxyethane), independent of temperature, reveals the effect of ion-ion interaction on the conductivity maximum, with the solvent permittivity, viscosity, and ionic radii remaining unchanged.more » Synthesis, analysis, and purification of lithium bis[3-fluoro-1,2-benzenediolato(2-)O,O{prime}]borate, which is a candidate for lithium batteries, is described.« less
  • A chelate complex with boron, lithium bis[2,3-naphthalenediolato(2-)-O,O{prime}]borate was used in lithium battery electrolytes for Li/V{sub 2}O{sub 5} prototype cells. This lithium salt remains a safe and thermally stable compound up to 320 C without melting. A high specific conductivity (4.63 mS/cm) is exhibited in spite of its high viscosity (1.732 cP) in a 0.5 mol/dm{sup 3} electrolyte/ethylene carbonate-1,2-dimethoxyethane (mol ratio 2:3) binary solvent mixture at 25 C. Based on the discharge characteristics of a Li/V{sub 2}O{sub 5} prototype cell, this lithium salt electrolyte resulted in high energy density (460 Wh/kg) at a cutoff potential of 2.5 V vs. Li/Li{sup +}.
  • In this paper, we have studied the dynamics and relaxation of charge carriers in poly(methylmethacrylate)-lithium salt based polymer electrolytes plasticized with ethylene carbonate. Structural and thermal properties have been examined using X-ray diffraction and differential scanning calorimetry, respectively. We have analyzed the complex conductivity spectra by using power law model coupled with the contribution of electrode polarization at low frequencies and high temperatures. The temperature dependence of the ionic conductivity and crossover frequency exhibits Vogel-Tammann-Fulcher type behavior indicating a strong coupling between the ionic and the polymer chain segmental motions. The scaling of the ac conductivity indicates that relaxation dynamicsmore » of charge carriers follows a common mechanism for all temperatures and ethylene carbonate concentrations. The analysis of the ac conductivity also shows the existence of a nearly constant loss in these polymer electrolytes at low temperatures and high frequencies. The fraction of free anions and ion pairs in polymer electrolyte have been obtained from the analysis of Fourier transform infrared spectra. It is observed that these quantities influence the behavior of the composition dependence of the ionic conductivity.« less