Structure and dynamics of highly concentrated LiTFSI/acetonitrile electrolytes
Lundin, Filippa ; Aguilera, Luis ; Hansen, Henriette Wase ; Lages, Sebastian LU ; Labrador, Ana LU
; Niss, Kristine
; Frick, Bernhard
and Matic, Aleksandar
(2021)
In Physical Chemistry Chemical Physics
23(25).
p.13819-13826
- Abstract
High salt concentration has been shown to induce increased electrochemical stability in organic solvent-based electrolytes. Accompanying the change in bulk properties is a structural ordering on mesoscopic length scales and changes in the ion transport mechanism have also been suggested. Here we investigate the local structure and dynamics in highly concentrated acetonitrile electrolytes as a function of salt concentration. Already at low concentrations ordering on microscopic length scales in the electrolytes is revealed by small angle X-ray scattering, as a result of correlations of Li+ coordinating clusters. For higher salt concentrations a charge alternation-like ordering is found as anions start to take part in the solvation.... (More)
High salt concentration has been shown to induce increased electrochemical stability in organic solvent-based electrolytes. Accompanying the change in bulk properties is a structural ordering on mesoscopic length scales and changes in the ion transport mechanism have also been suggested. Here we investigate the local structure and dynamics in highly concentrated acetonitrile electrolytes as a function of salt concentration. Already at low concentrations ordering on microscopic length scales in the electrolytes is revealed by small angle X-ray scattering, as a result of correlations of Li+ coordinating clusters. For higher salt concentrations a charge alternation-like ordering is found as anions start to take part in the solvation. Results from quasi-elastic neutron spectroscopy reveal a jump diffusion dynamical process with jump lengths virtually independent of both temperature and Li-salt concentration. The jump can be envisaged as dissociation of a solvent molecule or anion from a particular Li+ solvation structure. The residence time, 50-800 ps, between the jumps is found to be highly temperature and Li-salt concentration dependent, with shorter residence times for higher temperature and lower concentrations. The increased residence time at high Li-salt concentration can be attributed to changes in the interaction of the solvation shell as a larger fraction of TFSI anions take part in the solvation, forming more stable solvation shells.
(Less)
- author
- Lundin, Filippa
; Aguilera, Luis
; Hansen, Henriette Wase
; Lages, Sebastian
LU
; Labrador, Ana
LU
; Niss, Kristine
; Frick, Bernhard
and Matic, Aleksandar
- organization
- publishing date
- 2021-07-07
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Physical Chemistry Chemical Physics
- volume
- 23
- issue
- 25
- pages
- 8 pages
- publisher
- Royal Society of Chemistry
- external identifiers
-
- pmid:34195732
- scopus:85109073266
- ISSN
- 1463-9076
- DOI
- 10.1039/d1cp02006d
- language
- English
- LU publication?
- yes
- additional info
- Funding Information: This research was financially supported by the Swedish Foundation for Strategic Research (SSF) within the Swedish national graduate school in neutron scattering (SwedNess) grant number GSn15-0008.
- id
- aa519312-eff6-4f44-ae0e-93e27dc15a8b
- date added to LUP
- 2021-08-18 23:06:46
- date last changed
- 2024-06-29 15:45:36
@article{aa519312-eff6-4f44-ae0e-93e27dc15a8b,
abstract = {{<p>High salt concentration has been shown to induce increased electrochemical stability in organic solvent-based electrolytes. Accompanying the change in bulk properties is a structural ordering on mesoscopic length scales and changes in the ion transport mechanism have also been suggested. Here we investigate the local structure and dynamics in highly concentrated acetonitrile electrolytes as a function of salt concentration. Already at low concentrations ordering on microscopic length scales in the electrolytes is revealed by small angle X-ray scattering, as a result of correlations of Li+ coordinating clusters. For higher salt concentrations a charge alternation-like ordering is found as anions start to take part in the solvation. Results from quasi-elastic neutron spectroscopy reveal a jump diffusion dynamical process with jump lengths virtually independent of both temperature and Li-salt concentration. The jump can be envisaged as dissociation of a solvent molecule or anion from a particular Li+ solvation structure. The residence time, 50-800 ps, between the jumps is found to be highly temperature and Li-salt concentration dependent, with shorter residence times for higher temperature and lower concentrations. The increased residence time at high Li-salt concentration can be attributed to changes in the interaction of the solvation shell as a larger fraction of TFSI anions take part in the solvation, forming more stable solvation shells. </p>}},
author = {{Lundin, Filippa and Aguilera, Luis and Hansen, Henriette Wase and Lages, Sebastian and Labrador, Ana and Niss, Kristine and Frick, Bernhard and Matic, Aleksandar}},
issn = {{1463-9076}},
language = {{eng}},
month = {{07}},
number = {{25}},
pages = {{13819--13826}},
publisher = {{Royal Society of Chemistry}},
series = {{Physical Chemistry Chemical Physics}},
title = {{Structure and dynamics of highly concentrated LiTFSI/acetonitrile electrolytes}},
url = {{http://dx.doi.org/10.1039/d1cp02006d}},
doi = {{10.1039/d1cp02006d}},
volume = {{23}},
year = {{2021}},
}