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

Title: Decoupling charge transport from the structural dynamics in room temperature ionic liquids

Abstract

Light scattering and dielectric spectroscopy measurements were performed on the room temperature ionic liquid (RTIL) [C4mim][NTf2] in a broad temperature and frequency range. Ionic conductivity was used to estimate self-diffusion of ions, while light scattering was used to study structural relaxation. We demonstrate that the ionic diffusion decouples from the structural relaxation processes the temperature of the sample decreases toward Tg. The strength of the decoupling appears to be significantly lower than that expected for a supercooled liquid of similar fragility. The structural relaxation process in the RTIL follows well the high-temperature mode coupling theory (MCT) scenario.Using the MCT analysis we estimated the dynamic crossover temperature in [C4mim][NTf2]to be Tc ~ 225 ± 5 K. However, our analysis reveals no sign of the dynamic crossover in the ionic diffusion process.

Authors:
 [1];  [2];  [2]; ORCiD logo [2]; ORCiD logo [2];  [2]; ORCiD logo [2]
  1. University of Tennessee (UTK) and Oak Ridge National Laboratory (ORNL)
  2. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1041098
DOE Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 135; Journal Issue: 11; Journal ID: ISSN 0021-9606
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CHARGE TRANSPORT; DECOUPLING; DIELECTRIC MATERIALS; DIFFUSION; FREQUENCY RANGE; IONIC CONDUCTIVITY; LIGHT SCATTERING; MOLTEN SALTS; RELAXATION; SELF-DIFFUSION; SPECTROSCOPY

Citation Formats

Griffin, Phillip, Agapov, Alexander L., Kisliuk, Alexander, Sun, Xiao-Guang, Dai, Sheng, Novikov, Vladimir, and Sokolov, Alexei P. Decoupling charge transport from the structural dynamics in room temperature ionic liquids. United States: N. p., 2011. Web. doi:10.1063/1.3638269.
Griffin, Phillip, Agapov, Alexander L., Kisliuk, Alexander, Sun, Xiao-Guang, Dai, Sheng, Novikov, Vladimir, & Sokolov, Alexei P. Decoupling charge transport from the structural dynamics in room temperature ionic liquids. United States. doi:10.1063/1.3638269.
Griffin, Phillip, Agapov, Alexander L., Kisliuk, Alexander, Sun, Xiao-Guang, Dai, Sheng, Novikov, Vladimir, and Sokolov, Alexei P. Thu . "Decoupling charge transport from the structural dynamics in room temperature ionic liquids". United States. doi:10.1063/1.3638269.
@article{osti_1041098,
title = {Decoupling charge transport from the structural dynamics in room temperature ionic liquids},
author = {Griffin, Phillip and Agapov, Alexander L. and Kisliuk, Alexander and Sun, Xiao-Guang and Dai, Sheng and Novikov, Vladimir and Sokolov, Alexei P.},
abstractNote = {Light scattering and dielectric spectroscopy measurements were performed on the room temperature ionic liquid (RTIL) [C4mim][NTf2] in a broad temperature and frequency range. Ionic conductivity was used to estimate self-diffusion of ions, while light scattering was used to study structural relaxation. We demonstrate that the ionic diffusion decouples from the structural relaxation processes the temperature of the sample decreases toward Tg. The strength of the decoupling appears to be significantly lower than that expected for a supercooled liquid of similar fragility. The structural relaxation process in the RTIL follows well the high-temperature mode coupling theory (MCT) scenario.Using the MCT analysis we estimated the dynamic crossover temperature in [C4mim][NTf2]to be Tc ~ 225 ± 5 K. However, our analysis reveals no sign of the dynamic crossover in the ionic diffusion process.},
doi = {10.1063/1.3638269},
journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 11,
volume = 135,
place = {United States},
year = {2011},
month = {9}
}

Works referenced in this record:

Viscosity of a vitreous potassium nitrate - calcium nitrate mixture
journal, December 1969

  • Weiler, R.; Blaser, S.; Macedo, Pedro B.
  • The Journal of Physical Chemistry, Vol. 73, Issue 12
  • DOI: 10.1021/j100846a019

Ionic-liquid materials for the electrochemical challenges of the future
journal, July 2009

  • Armand, Michel; Endres, Frank; MacFarlane, Douglas R.
  • Nature Materials, Vol. 8, Issue 8, p. 621-629
  • DOI: 10.1038/nmat2448

Breakdown of Time−Temperature Superposition Principle and Universality of Chain Dynamics in Polymers
journal, May 2006

  • Ding, Yifu; Sokolov, Alexei P.
  • Macromolecules, Vol. 39, Issue 9
  • DOI: 10.1021/ma052607b

Self-Diffusion of Supercooled o -Terphenyl near the Glass Transition Temperature
journal, January 2006

  • Mapes, Marie K.; Swallen, Stephen F.; Ediger, M. D.
  • The Journal of Physical Chemistry B, Vol. 110, Issue 1
  • DOI: 10.1021/jp0555955

Physicochemical Properties and Structures of Room Temperature Ionic Liquids. 1. Variation of Anionic Species
journal, October 2004

  • Tokuda, Hiroyuki; Hayamizu, Kikuko; Ishii, Kunikazu
  • The Journal of Physical Chemistry B, Vol. 108, Issue 42
  • DOI: 10.1021/jp047480r

Dynamics of glass‐forming liquids. I. Temperature‐derivative analysis of dielectric relaxation data
journal, April 1995

  • Stickel, F.; Fischer, E. W.; Richert, R.
  • The Journal of Chemical Physics, Vol. 102, Issue 15
  • DOI: 10.1063/1.469071

Relaxation processes in supercooled liquids
journal, March 1992


Charge transport and mass transport in imidazolium-based ionic liquids
journal, May 2008


Crystal growth kinetics exhibit a fragility-dependent decoupling from viscosity
journal, January 2008

  • Ediger, M. D.; Harrowell, Peter; Yu, Lian
  • The Journal of Chemical Physics, Vol. 128, Issue 3
  • DOI: 10.1063/1.2815325

Inadequacies of Viscosity Theories for a Vitreous KNO3-Ca(NO3)2 Melt
journal, February 1971


Charge Transport and Dipolar Relaxations in Imidazolium-Based Ionic Liquids
journal, January 2010

  • Krause, C.; Sangoro, J. R.; Iacob, C.
  • The Journal of Physical Chemistry B, Vol. 114, Issue 1
  • DOI: 10.1021/jp908519u

Resolving the Mystery of the Chain Friction Mechanism in Polymer Liquids
journal, June 2009


A phenomenological model for the Meyer-Neldel rule
journal, October 1986


Indications for a change of diffusion mechanism in supercooled liquids
journal, September 1990


Unique Spatial Heterogeneity in Ionic Liquids
journal, September 2005

  • Wang, Yanting; Voth, Gregory A.
  • Journal of the American Chemical Society, Vol. 127, Issue 35
  • DOI: 10.1021/ja053796g

Dynamics of glass‐forming liquids. II. Detailed comparison of dielectric relaxation, dc‐conductivity, and viscosity data
journal, February 1996

  • Stickel, F.; Fischer, E. W.; Richert, R.
  • The Journal of Chemical Physics, Vol. 104, Issue 5
  • DOI: 10.1063/1.470961

Influence of molecular weight on dynamic crossover temperature in linear polymers
journal, June 2008


Self-Diffusion and Viscosity of Low Molecular Weight Polystyrene over a Wide Temperature Range
journal, February 2004

  • Urakawa, Osamu; Swallen, Stephen F.; Ediger, M. D.
  • Macromolecules, Vol. 37, Issue 4
  • DOI: 10.1021/ma0352025

Heterogeneity at the Glass Transition:  Translational and Rotational Self-Diffusion
journal, October 1997

  • Chang, Inyong; Sillescu, Hans
  • The Journal of Physical Chemistry B, Vol. 101, Issue 43
  • DOI: 10.1021/jp9640989

Appearance of a Debye process at the conductivity relaxation frequency of a viscous liquid
journal, March 2011

  • Richert, Ranko; Agapov, Alexander; Sokolov, Alexei P.
  • The Journal of Chemical Physics, Vol. 134, Issue 10
  • DOI: 10.1063/1.3565481

A short history of ionic liquids—from molten salts to neoteric solvents
journal, March 2002


Protic Ionic Liquids:  Properties and Applications
journal, January 2008

  • Greaves, Tamar L.; Drummond, Calum J.
  • Chemical Reviews, Vol. 108, Issue 1, p. 206-237
  • DOI: 10.1021/cr068040u

Ionic Liquids:  Ion Mobilities, Glass Temperatures, and Fragilities
journal, June 2003

  • Xu, Wu; Cooper, Emanuel I.; Angell, C. Austen
  • The Journal of Physical Chemistry B, Vol. 107, Issue 25
  • DOI: 10.1021/jp0275894

Electrical relaxation in a glass-forming molten salt
journal, March 1974

  • Howell, F. S.; Bose, R. A.; Macedo, P. B.
  • The Journal of Physical Chemistry, Vol. 78, Issue 6
  • DOI: 10.1021/j100599a016

Heterogeneous dynamics in liquids: fluctuations in space and time
journal, May 2002


Temperature Dependence of Segmental and Terminal Relaxation in Atactic Polypropylene Melts
journal, August 2001

  • Roland, C. M.; Ngai, K. L.; Santangelo, P. G.
  • Macromolecules, Vol. 34, Issue 18
  • DOI: 10.1021/ma002121p

Breakdown of time–temperature superposition: From experiment to the coupling model and beyond
journal, November 2007


Identification of Different Modes of Molecular Motion in Polymers That Cause Thermorheological Complexity
journal, July 1995

  • Ngai, K. L.; Plazek, D. J.
  • Rubber Chemistry and Technology, Vol. 68, Issue 3
  • DOI: 10.5254/1.3538749

Crossover in dynamics of polymeric liquids: Back toTll?
journal, January 2000


Physicochemical Properties and Structures of Room Temperature Ionic Liquids. 2. Variation of Alkyl Chain Length in Imidazolium Cation
journal, April 2005

  • Tokuda, Hiroyuki; Hayamizu, Kikuko; Ishii, Kunikazu
  • The Journal of Physical Chemistry B, Vol. 109, Issue 13
  • DOI: 10.1021/jp044626d

Electrical conductivity and translational diffusion in the 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid
journal, June 2008

  • Sangoro, J.; Iacob, C.; Serghei, A.
  • The Journal of Chemical Physics, Vol. 128, Issue 21
  • DOI: 10.1063/1.2921796

High-temperature dynamics in glass-forming liquids
journal, November 1995


Crossover region of dynamic glass transition: general trends and individual aspects
journal, February 2001


The Temperature Dependence of the Viscoelastic Behavior of Poly(vinyl acetate)
journal, January 1980


Universality of the dynamic crossover in glass-forming liquids: A “magic” relaxation time
journal, March 2003


Universal scaling of charge transport in glass-forming ionic liquids
journal, January 2009

  • Sangoro, J. R.; Iacob, C.; Serghei, A.
  • Phys. Chem. Chem. Phys., Vol. 11, Issue 6
  • DOI: 10.1039/b816106b

CHEMISTRY: Ionic Liquids--Solvents of the Future?
journal, October 2003


Ionic Liquids
journal, December 1999

  • Holbrey, J. D.; Seddon, K. R.
  • Clean Technologies and Environmental Policy, Vol. 1, Issue 4
  • DOI: 10.1007/s100980050036

Self-Diffusion of tris -Naphthylbenzene near the Glass Transition Temperature
journal, January 2003


Applications of functionalized ionic liquids
journal, October 2006

  • Li, Xuehui; Zhao, Dongbin; Fei, Zhaofu
  • Science in China Series B: Chemistry, Vol. 49, Issue 5
  • DOI: 10.1007/s11426-006-2020-y

S PATIALLY H ETEROGENEOUS D YNAMICS IN S UPERCOOLED L IQUIDS
journal, October 2000


The random free‐energy barrier model for ac conduction in disordered solids
journal, September 1988

  • Dyre, Jeppe C.
  • Journal of Applied Physics, Vol. 64, Issue 5
  • DOI: 10.1063/1.341681