Abstract
Present and future electrochemical devices employing advanced electrode and electrolyte materials are expected to operate in diverse environments, where they are exposed to variable conditions, such as changing humidity levels. Such conditions can possibly alter the microscopic mechanisms that influence the electrochemical performance. Here, using quasi-elastic neutron scattering and molecular dynamics simulations, we investigate the influence of humidity exposure on a room-temperature ionic liquid, [EMIm+][Tf2N-], in Ti3C2Tx MXene. Absorbed water enhances the microscopic mobility of confined [EMIm+][Tf2N-], even though the ionic liquid itself is not very hygroscopic. The absorbed water molecules predominantly reside on the termination groups of the more hydrophilic MXene layers, thereby displacing the ions from the surface and facilitating their motions in the MXene matrix.
Original language | English |
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Pages (from-to) | 27561-27566 |
Number of pages | 6 |
Journal | Journal of Physical Chemistry C |
Volume | 122 |
Issue number | 48 |
DOIs | |
State | Published - Dec 6 2018 |
Funding
This work was supported as part of the Fluid Interface Reactions, Structures and Transport (FIRST) Center, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. The work at ORNL’s Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for U.S. DOE under Contract no. DEAC05-00OR22725. Access to the HFBS was provided by the Center for High Resolution Neutron Scattering, a partnership between the NIST and the NSF under agreement no. DMR-1508249. Certain commercial material suppliers are identified in this paper to foster understanding. Such identification does not imply recommendation or endorsement by the National Institute of Standards and Technology nor does it imply that the materials or equipment identified is necessarily the best available for the purpose.