Comparative microscopic dynamics in a room-temperature ionic liquid confined in carbon pores characterized by reversible and irreversible ion immobilization

Conference · Fri Jun 01 00:00:00 EDT 2018 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.5039290· OSTI ID:1465071

Mamontov, Eugene  ^[1]; Mahurin, Shannon Mark  ^[1]; Dai, Sheng  ^[1]

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1. ORNL

In search for the origin of irreversible ion immobilization under applied electric potential recently reported for a prototypical room-temperature ionic liquid electrolyte, [emim][Tf₂N], confined in 1.5 nm carbon pores, here we compare the microscopic dynamics of cations in [emim][Tf₂N] in the 1.5 nm and 6.7 nm carbon pores; in the latter, ion immobilization under applied electric potential is reversible. Using quasielastic neutron scattering, we find that the cation translational diffusivity is reasonably well defined on at least a nanometer length scale in the 6.7 nm pores, but not the 1.5 nm pores. Severely impeded microscopic dynamics of the confined electrolyte may be one of the factors differentiating the 1.5 nm pores from their larger counterparts and contributing to the irreversible immobilization of ions under applied electric potential.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1465071
• Journal Information: AIP Conference Proceedings, Vol. 1965; Conference: Joint Conference on Quasielastic Neutron Scattering and the Workshop on Inelastic Neutron Spectrometers (QENS/WINS 2016) , Potsdam, Germany, September 5-9, 2016; ISSN 0094-243X
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English