| Autor: |
Mönich C; Institute of Physical Chemistry, University of Münster, Corrensstraße 28/30, Münster 48149, Germany., Andersson R; Department of Chemistry - Ångström Laboratory, Uppsala University, Box 538, Uppsala SE-751 21, Sweden., Hernández G; Department of Chemistry - Ångström Laboratory, Uppsala University, Box 538, Uppsala SE-751 21, Sweden., Mindemark J; Department of Chemistry - Ångström Laboratory, Uppsala University, Box 538, Uppsala SE-751 21, Sweden., Schönhoff M; Institute of Physical Chemistry, University of Münster, Corrensstraße 28/30, Münster 48149, Germany. |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of the American Chemical Society [J Am Chem Soc] 2024 Apr 12. Date of Electronic Publication: 2024 Apr 12. |
| DOI: |
10.1021/jacs.3c12272 |
| Abstrakt: |
The growing demand for energy storage devices worldwide combined with limited resources for lithium attracts interest in other alkali or alkaline earth metals. In addition to conductivity, the cation transference number T + is a decisive parameter to rank the electrolyte performance. However, the existing experimental methods for its determination suffer from various intrinsic problems. We demonstrate here a novel approach for T + determination based on determining the total conductivity with impedance spectroscopy (IS) and the partial conductivity of the anion species, with the latter being obtained from the anion mobility by electrophoretic NMR. First, this eNMR/IS approach is validated by comparing T + values from different methods in a Li-based solvate ionic liquid electrolyte. Then, it is applied to obtain T + of cations with nuclei not detectable in NMR transport measurements, employing bis(trifluoromethanesulfonyl)imide (TFSI)-based metal salts. Solvate ionic liquids consisting of triethylene glycol dimethyl ether (G3) and Mg(TFSI) 2 or NaTFSI yield values of T Na and T Mg on the order of 0.4, similar to T Li . Furthermore, we apply the method to polymer electrolytes, again testing the concept with LiTFSI, and finally investigating NaTFSI, KTFSI, and Mg(TFSI) 2 in poly(ethylene oxide). Values of T Na and T K are in the range of 0.14-0.2, similar to those of T Li , while Mg 2+ shows a higher transference number ( T Mg = 0.3). The method is very versatile as it allows quantification of T + for any type of cation, and moreover, it is applicable to highly concentrated electrolytes without suffering from assumptions about dissociation or from unknown interfacial resistances which impede electrochemical methods. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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