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Ionic Liquid Electrolytes for Metal-Air Batteries: Interactions between O2, Zn2+ and H2O Impurities

Alwast, D.; Schnaidt, J.; Jusys, Z.; Behm, R. J.

Motivated by the potential of ionic liquids (ILs) to replace traditional aqueous electrolytes in Zn-air batteries, we investigated the effects arising from mutual interactions between O₂ and Zn(TFSI)₂ as well as the influence of H₂O impurities in the oxygen reduction/oxygen evolution reaction (ORR/OER) and in Zn deposition/dissolution on a glassy carbon (GC) electrode in the ionic liquid N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)-imide (BMP-TFSI) by differential electrochemical mass spectrometry. This allowed us to determine the number of electrons transferred per reduced/evolved O₂ molecule. In O₂ saturated neat BMP-TFSI the ORR and OER were found to be reversible, in Zn²⁺containing IL Zn deposition/stripping proceeds reversibly as well. Simultaneous addition of O₂ and Zn²⁺ suppresses Zn metal deposition, instead ZnO₂ is formed in the ORR, which is reversible only after excursions to very negative potentials (−1.4 V). The addition of water leads to an enhancement of all processes described above, which is at least partly explained by a higher mobility of O₂ and Zn²⁺ in the water containing electrolytes. Consequences for the operation of Zn-air batteries in these electrolytes are discussed.

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Verlagsausgabe §
DOI: 10.5445/IR/1000104946
Veröffentlicht am 14.01.2020
DOI: 10.1149/2.0052007JES
Zitationen: 2
Web of Science
Zitationen: 3
Cover der Publikation
Zugehörige Institution(en) am KIT Helmholtz-Institut Ulm (HIU)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2020
Sprache Englisch
Identifikator ISSN: 0013-4651, 1945-7111
KITopen-ID: 1000104946
HGF-Programm 37.01.01 (POF III, LK 01)
Fundamentals and Materials
Erschienen in Journal of the Electrochemical Society
Band 167
Heft 1
Seiten Art. Nr.: 070505
Vorab online veröffentlicht am 04.12.2019
Nachgewiesen in Web of Science
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