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Molecular Dynamic Simulations of Ionic Liquid's Structural Variations from Three to One Layers inside a Series of Slit and Cylindrical Nanopores

Ma, Ke; Wang, Xuewei; Forsman, Jan LU and Woodward, Clifford E. (2017) In Journal of Physical Chemistry C 121(25). p.13539-13548
Abstract

We apply molecular dynamic simulations to describe [C2mim+][Tf2N-] ionic liquids and its mixtures with solvents confined inside carbon nanopores. Both slit and cylindrical pores are modeled to determine the influence of pore geometry on the electric double layer (EDL) structure and capacitance. Two types of solvents are selected to dilute the ionic liquids in order to establish the effect of solvent polarity. The number of cations, anions, and solvents is chosen to be consistent with their densities in the bulk state. We focus on the structural changes of ionic liquids and their relation to the oscillation in capacitance as a function of varying nanopore size. Structural transitions are... (More)

We apply molecular dynamic simulations to describe [C2mim+][Tf2N-] ionic liquids and its mixtures with solvents confined inside carbon nanopores. Both slit and cylindrical pores are modeled to determine the influence of pore geometry on the electric double layer (EDL) structure and capacitance. Two types of solvents are selected to dilute the ionic liquids in order to establish the effect of solvent polarity. The number of cations, anions, and solvents is chosen to be consistent with their densities in the bulk state. We focus on the structural changes of ionic liquids and their relation to the oscillation in capacitance as a function of varying nanopore size. Structural transitions are analyzed from one layer to two layers and three layers within the confinement of the nanoscale pores. Compared with slit pores, the capacitance oscillates more strongly for cylindrical pores where ions form two peaks instead of combining into a single peak in the middle of the pore. The addition of solvent does not give rise to a larger capacitance despite the solvent's closer approach to the electrode.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Physical Chemistry C
volume
121
issue
25
pages
10 pages
publisher
The American Chemical Society
external identifiers
  • scopus:85022214916
  • wos:000404828600012
ISSN
1932-7447
DOI
10.1021/acs.jpcc.7b03319
language
English
LU publication?
yes
id
40e026c7-2620-4453-a382-893ca637ad96
date added to LUP
2017-07-24 12:14:03
date last changed
2018-01-14 04:34:34
@article{40e026c7-2620-4453-a382-893ca637ad96,
  abstract     = {<p>We apply molecular dynamic simulations to describe [C<sub>2</sub>mim<sup>+</sup>][Tf<sub>2</sub>N<sup>-</sup>] ionic liquids and its mixtures with solvents confined inside carbon nanopores. Both slit and cylindrical pores are modeled to determine the influence of pore geometry on the electric double layer (EDL) structure and capacitance. Two types of solvents are selected to dilute the ionic liquids in order to establish the effect of solvent polarity. The number of cations, anions, and solvents is chosen to be consistent with their densities in the bulk state. We focus on the structural changes of ionic liquids and their relation to the oscillation in capacitance as a function of varying nanopore size. Structural transitions are analyzed from one layer to two layers and three layers within the confinement of the nanoscale pores. Compared with slit pores, the capacitance oscillates more strongly for cylindrical pores where ions form two peaks instead of combining into a single peak in the middle of the pore. The addition of solvent does not give rise to a larger capacitance despite the solvent's closer approach to the electrode.</p>},
  author       = {Ma, Ke and Wang, Xuewei and Forsman, Jan and Woodward, Clifford E.},
  issn         = {1932-7447},
  language     = {eng},
  month        = {06},
  number       = {25},
  pages        = {13539--13548},
  publisher    = {The American Chemical Society},
  series       = {Journal of Physical Chemistry C},
  title        = {Molecular Dynamic Simulations of Ionic Liquid's Structural Variations from Three to One Layers inside a Series of Slit and Cylindrical Nanopores},
  url          = {http://dx.doi.org/10.1021/acs.jpcc.7b03319},
  volume       = {121},
  year         = {2017},
}