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Time Resolved Measurements of pH in Aqueous Magnesium‐Air Batteries during Discharge and Its Impact for Future Applications

Braun, Tobias ; Dinda, Sirshendu; Pammer, Frank; Fichtner, Maximilian 1
1 Helmholtz-Institut Ulm (HIU), Karlsruher Institut für Technologie (KIT)

Abstract:

In aqueous magnesium air batteries, the influence of the electrochemical behavior on pH of the electrolyte has not been investigated yet, which has a critical effect on the cell performance. We have monitored the evolution of the pH at various discharge current densities in situ in the Mg-air primary cells, which produce sparingly soluble magnesium hydroxide (Mg(OH)$_{2}$). These experiments show the temporal evolution of the pH of the electrolyte in the cell discharge, depending on the current density. The pH first increases rapidly to a maximum of pH 11 and then drops down slowly to the equilibrium at pH 10.7. At the peak pH oversaturation of Mg(OH)$_{2}$ is paramount, leading to the precipitation which balances the Mg(OH)$_{2}$ concentration in the electrolyte. This precipitation process coats both cathode and anode which leads to a decrease in cell efficiency and voltage. The results show that the cell design of Mg-air batteries is important for their lifetime and cell performance. The performance of the aqueous magnesium cell is increased several folds when the design is changed to a simple electrolyte flow cell.


Verlagsausgabe §
DOI: 10.5445/IR/1000143648
Veröffentlicht am 10.03.2022
Originalveröffentlichung
DOI: 10.1002/celc.202101191
Scopus
Zitationen: 3
Web of Science
Zitationen: 4
Dimensions
Zitationen: 5
Cover der Publikation
Zugehörige Institution(en) am KIT Helmholtz-Institut Ulm (HIU)
Publikationstyp Zeitschriftenaufsatz
Publikationsdatum 14.01.2022
Sprache Englisch
Identifikator ISSN: 2196-0216
KITopen-ID: 1000143648
HGF-Programm 38.02.01 (POF IV, LK 01) Fundamentals and Materials
Erschienen in ChemElectroChem
Verlag John Wiley and Sons
Band 9
Heft 1
Seiten Art.-Nr.: e202101191
Vorab online veröffentlicht am 12.01.2022
Nachgewiesen in Scopus
Dimensions
Web of Science
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