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Transport Properties, Local Coordination, and Thermal Stability of the Water/Diethylmethylammonium Methanesulfonate Binary System
Author(s) -
Yaghini N.,
Garaga M. N.,
Martinelli A.
Publication year - 2016
Publication title -
fuel cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.485
H-Index - 69
eISSN - 1615-6854
pISSN - 1615-6846
DOI - 10.1002/fuce.201500064
Subject(s) - chemistry , ionic liquid , ionic bonding , raman spectroscopy , thermal stability , ion exchange , ion , water transport , inorganic chemistry , proton exchange membrane fuel cell , membrane , proton transport , chemical engineering , organic chemistry , water flow , physics , environmental engineering , optics , engineering , catalysis , biochemistry
Ammonium based protic ionic liquids are highlighted for their great potential to sustain proton transport in proton exchange membrane (PEM) fuel cells. Yet, there remain questions concerning the effect of water produced by the fuel cell at the cathode side on the performance of the ionic liquid. In this contribution we report the effect of water on the transport properties and the local coordination in the binary system of the protic ionic liquid diethylmethylammonium methanesulfonate ([DEMA][OMs]) and water, employing 1 H NMR, Raman, and infrared spectroscopy. We observe that the self‐diffusion of cations and anions increases with the water content and that cations and anions diffuse at the same rate at all concentrations investigated. 1 H NMR and vibrational spectroscopy, on the other hand, indicate that added water interacts primarily with the anion and slightly affects the ionicity of the ionic liquid. In addition, by investigating the thermal stability of the binary system we find that although [DEMA][OMs] displays a continuous loss of water upon increasing temperature a fraction of water molecules can be retained even above 120 °C, and that the complete loss of water is immediately followed by decomposition, which is observed to occur at about 185 °C.