Influence of complexing additives on the reversible deposition/dissolution of magnesium in an ionic liquid

peer-reviewed
Erstveröffentlichung
2021-01-26Authors
Weber, Isabella
Ingenmey, Johannes
Schnaidt, Johannes
Kirchner, Barbara
Behm, Rolf Jürgen
Wissenschaftlicher Artikel
Published in
ChemElectroChem ; 8 (2021), 2. - S. 390-402. - eISSN 2196-0216
Link to original publication
https://dx.doi.org/10.1002/celc.202001488Faculties
Fakultät für NaturwissenschaftenInstitutions
Institut für Oberflächenchemie und KatalyseExternal cooperations
Helmholtz-Institut UlmDocument version
published version (publisher's PDF)Abstract
Better together: Electrochemical measurements and quantum chemical calculations are presented, which show that addition of crown ether enhances the reversibility of Mg deposition/dissolution from a MgTFSI2-containing ionic liquid by strongly coordinating to Mg2+, weakening the [Mg2+−TFSI−] interaction and TFSI− decomposition. BH4− is assumed to support this by acting both as coordinating ligand and as water scavenger. Aiming at a fundamental understanding of the synergistic effects of different additives on the electrochemical Mg deposition/dissolution in an ionic liquid, we have systematically investigated these processes in a combined electrochemical and theoretical study, using 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) imide (BMP-TFSI) as the solvent and a cyclic ether (18-crown-6) and magnesium borohydride as additives. Both crown ether and BH4− improve Mg deposition, its reversibility, and cycling stability. The combined presence of both additives and their concentration relative to that of Mg2+ are decisive for more facile and reversible Mg deposition/dissolution. These results and those of quantum chemical calculations indicate that 18-crown-6 can partly displace TFSI− from its direct coordination to Mg2+. Furthermore, the interaction between Mg2+ and directly coordinated TFSI− is weakened by coordination with 18-crown-6, preventing its Mg+-induced decomposition. Finally, Mg deposition is improved by the weaker overall coordination upon Mg2+ reduction to Mg+.
DFG Project THU
EXC 2154 / POLiS / POLiS - Post Lithium Storage Cluster of Excellence / DFG / 390874152 [BE1201/22-1]
Project uulm
LuCaMag / Verbundvorhaben LuCaMag: Wege zu sekundären Mg/Ca – Luftbatterien / BMBF / 03EK3051C
Is supplemented by
https://chemistry-europe.onlinelibrary.wiley.com/action/downloadSupplement?doi=10.1002%2Fcelc.202001488&file=celc202001488-sup-0001-misc_information.pdfSubject headings
[GND]: Magnesium | Elektrochemie[LCSH]: Electrochemistry
[Free subject headings]: magnesium batteries | complexing additives | quantum chemical calculations
[DDC subject group]: DDC 540 / Chemistry & allied sciences
Metadata
Show full item recordDOI & citation
Please use this identifier to cite or link to this item: http://dx.doi.org/10.18725/OPARU-45423
Weber, Isabella et al. (2022): Influence of complexing additives on the reversible deposition/dissolution of magnesium in an ionic liquid. Open Access Repositorium der Universität Ulm und Technischen Hochschule Ulm. http://dx.doi.org/10.18725/OPARU-45423
Citation formatter >