Journal Article

FZJ-2015-01306

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png The influence of a hierarchical porous carbon network on the coherent dynamics of a nanoconfined room temperature ionic liquid: A neutron spin echo and atomistic simulation investigation

Bañuelos, J. L. (Corresponding Author) ; Feng, G. ; Fulvio, P. F. ; Li, S. ; Rother, G. ; Arend, N.FZJ* ; Faraone, A. ; Dai, S. ; Cummings, P. T. ; Wesolowski, D. J.

2014
Elsevier Science Amsterdam [u.a.]

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Please use a persistent id in citations: doi:10.1016/j.carbon.2014.07.020

Abstract: The molecular-scale dynamic properties of the room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, or [C4mim+][Tf2N−], confined in hierarchical microporous–mesoporous carbon, were investigated using neutron spin echo (NSE) and molecular dynamics (MD) simulations. Both NSE and MD reveal pronounced slowing of the overall collective dynamics, including the presence of an immobilized fraction of RTIL at the pore wall, on the time scales of these approaches. A fraction of the dynamics, corresponding to RTIL inside 0.75 nm micropores located along the mesopore surfaces, are faster than those of RTIL in direct contact with the walls of 5.8 nm and 7.8 nm cylindrical mesopores. This behavior is ascribed to the near-surface confined-ion density fluctuations resulting from the ion–ion and ion–wall interactions between the micropores and mesopores as well as their confinement geometries. Strong micropore–RTIL interactions result in less-coordinated RTIL within the micropores than in the bulk fluid. Increasing temperature from 296 K to 353 K reduces the immobilized RTIL fraction and results in nearly an order of magnitude increase in the RTIL dynamics. The observed interfacial phenomena underscore the importance of tailoring the surface properties of porous carbons to achieve desirable electrolyte dynamic behavior, since this impacts the performance in applications such as electrical energy storage devices.

Keyword(s): Key Technologies (1st) ; Nano Science and Technology (1st) ; Energy (1st) ; Soft Condensed Matter (2nd) ; Condensed Matter Physics (2nd) ; Materials Science (2nd)

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Contributing Institute(s):

1. JCNS-FRM-II (JCNS (München) ; Jülich Centre for Neutron Science JCNS (München) ; JCNS-FRM-II)
2. Neutronenstreuung (Neutronenstreuung ; JCNS-1)
3. Neutronenstreuung (ICS-1)

Research Program(s):

1. 54G - JCNS (POF2-54G24) (POF2-54G24)

Experiment(s):

1. SNS-NSE: Neutron Spin Echo Spectrometer

Appears in the scientific report 2014

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Database coverage:
; Current Contents - Physical, Chemical and Earth Sciences ; IF >= 5 ; JCR ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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