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Influence of Chloride and Electrolyte Stability on Passivation Layer Evolution at the Negative Electrode of Mg Batteries Revealed by operando EQCM-D

Schick, Benjamin W. ; Vanoppen, Viktor ; Uhl, Matthias ; Kruck, Matthias ; Riedel, Sibylle ; Zhao-Karger, Zhirong ; Berg, Erik J. ; Hou, Xu LU orcid and Jacob, Timo (2024) In Angewandte Chemie - International Edition 63(52).
Abstract

Rechargeable magnesium batteries are promising for future energy storage. However, among other challenges, their practical application is hindered by low coulombic efficiencies of magnesium plating and stripping. Fundamental processes such as the formation, structure, and stability of passivation layers and the influence of different electrolyte components on them are still not fully understood. In this work, we gain unique insights into the initial Mg plating and stripping cycles by comparing magnesium bis(trifluoromethanesulfonyl)imide (Mg(TFSI)2)- and magnesium tetrakis(hexafluoroisopropyloxy)borate (Mg[B(hfip)4]2)-based electrolytes, each with and without MgCl2, on gold electrodes by... (More)

Rechargeable magnesium batteries are promising for future energy storage. However, among other challenges, their practical application is hindered by low coulombic efficiencies of magnesium plating and stripping. Fundamental processes such as the formation, structure, and stability of passivation layers and the influence of different electrolyte components on them are still not fully understood. In this work, we gain unique insights into the initial Mg plating and stripping cycles by comparing magnesium bis(trifluoromethanesulfonyl)imide (Mg(TFSI)2)- and magnesium tetrakis(hexafluoroisopropyloxy)borate (Mg[B(hfip)4]2)-based electrolytes, each with and without MgCl2, on gold electrodes by highly sensitive operando electrochemical quartz crystal microbalance with dissipation monitoring (EQCM−D) applying hydrodynamic spectroscopy. With the stable Mg[B(hfip)4]2-based electrolytes, highly efficient and interphase-free cycling is possible and passivation layers are attributed to electrolyte contaminants. These are forming and degrading during the so-called initial conditioning process. With the more reactive Mg(TFSI)2-based electrolyte, thick passivation layers with small pores are growing during cycling. We demonstrate that the addition of chloride lowers the amount of passivated Mg deposits in these electrolytes and accelerates the currentless dissolution of the passivation layer. This has a positive effect since we observe the most efficient cycling and uniform deposition when no interphase is present on the electrode.

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author
; ; ; ; ; ; ; and
publishing date
type
Contribution to journal
publication status
published
keywords
Electrochemistry, EQCM−D, Hydrodynamic Spectroscopy, Magnesium, Mg Battery Electrolyte
in
Angewandte Chemie - International Edition
volume
63
issue
52
article number
e202413058
publisher
John Wiley & Sons Inc.
external identifiers
  • pmid:39523208
  • scopus:85209779241
ISSN
1433-7851
DOI
10.1002/anie.202413058
language
English
LU publication?
no
additional info
Publisher Copyright: © 2024 The Author(s). Angewandte Chemie International Edition published by Wiley-VCH GmbH.
id
f3a71426-5c03-4f5c-b0e8-efdc7fdc81eb
date added to LUP
2025-12-05 22:20:46
date last changed
2025-12-09 14:53:33
@article{f3a71426-5c03-4f5c-b0e8-efdc7fdc81eb,
  abstract     = {{<p>Rechargeable magnesium batteries are promising for future energy storage. However, among other challenges, their practical application is hindered by low coulombic efficiencies of magnesium plating and stripping. Fundamental processes such as the formation, structure, and stability of passivation layers and the influence of different electrolyte components on them are still not fully understood. In this work, we gain unique insights into the initial Mg plating and stripping cycles by comparing magnesium bis(trifluoromethanesulfonyl)imide (Mg(TFSI)<sub>2</sub>)- and magnesium tetrakis(hexafluoroisopropyloxy)borate (Mg[B(hfip)<sub>4</sub>]<sub>2</sub>)-based electrolytes, each with and without MgCl<sub>2</sub>, on gold electrodes by highly sensitive operando electrochemical quartz crystal microbalance with dissipation monitoring (EQCM−D) applying hydrodynamic spectroscopy. With the stable Mg[B(hfip)<sub>4</sub>]<sub>2</sub>-based electrolytes, highly efficient and interphase-free cycling is possible and passivation layers are attributed to electrolyte contaminants. These are forming and degrading during the so-called initial conditioning process. With the more reactive Mg(TFSI)<sub>2</sub>-based electrolyte, thick passivation layers with small pores are growing during cycling. We demonstrate that the addition of chloride lowers the amount of passivated Mg deposits in these electrolytes and accelerates the currentless dissolution of the passivation layer. This has a positive effect since we observe the most efficient cycling and uniform deposition when no interphase is present on the electrode.</p>}},
  author       = {{Schick, Benjamin W. and Vanoppen, Viktor and Uhl, Matthias and Kruck, Matthias and Riedel, Sibylle and Zhao-Karger, Zhirong and Berg, Erik J. and Hou, Xu and Jacob, Timo}},
  issn         = {{1433-7851}},
  keywords     = {{Electrochemistry; EQCM−D; Hydrodynamic Spectroscopy; Magnesium; Mg Battery Electrolyte}},
  language     = {{eng}},
  month        = {{12}},
  number       = {{52}},
  publisher    = {{John Wiley & Sons Inc.}},
  series       = {{Angewandte Chemie - International Edition}},
  title        = {{Influence of Chloride and Electrolyte Stability on Passivation Layer Evolution at the Negative Electrode of Mg Batteries Revealed by operando EQCM-D}},
  url          = {{http://dx.doi.org/10.1002/anie.202413058}},
  doi          = {{10.1002/anie.202413058}},
  volume       = {{63}},
  year         = {{2024}},
}