Häcker, Joachim and Rommel, Tobias and Wagner, Norbert and Friedrich, Kaspar Andreas (2021) Insights into surficial processes of pristine and coated magnesium anodes in magnesium-sulfur batteries. 12th Electrochemical Impedance Analysis (EIA), 2021-11-29 - 2021-11-30, Online.
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Abstract
The electrochemical couple of magnesium and sulfur represents a promising high-energy battery system with improved sustainability due to higher abundance and better recyclability of the raw materials. Furthermore, the Mg-S battery offers improved safety as magnesium exhibits a lower tendency to form dendrites compared to lithium metal. However, in contrast to Li, magnesium metal is prone to be passivated by surface layers, e.g. a solid electrolyte interphase (SEI), comprising electrolyte decomposition products like MgF2 and MgO, but also sulfur compounds like MgSO4 and MgS [1]. Latter originates in sulfur species (S8 and Sx2-) being dissolute at the sulfur composite cathode and diffuse to the Mg anode surface. The passivation character of the SEI is due to the sluggish diffusion of Mg2+ ions in most solid materials caused by its large charge density. A promising approach to overcome this issue is the implication of an ex situ prepared surface layer with sufficient Mg ion conductivity, a so-called artificial SEI [2,3]. To gain insights into the surficial processes of pristine and artificial-SEI-coated Mg anodes, electrochemical impedance spectroscopy (EIS) was applied. To distinguish between stripping and plating in symmetrical Mg-Mg cells and to exclude the impedance response of the sulfur cathode in full Mg-S cells, half-cell EIS measurements are performed by the use of a magnesium metal reference ring electrode. By analyzing the distribution of relaxation times (DRT), Nyquist, Bode and f-Im plots, the number of present processes was determined and suitable equivalent circuits (EC) were defined. Comparing EIS spectra at open-cell voltage (OCV), different current densities and states of charge (SOC), the processes are assigned to the Mg/Mg2+ charge transfer and the SEI diffusion. Furthermore, the porous nature of the artificial SEI is identified and a high-ohmic adsorption layer was found to be present during extended non-current conditions.
Item URL in elib: | https://elib.dlr.de/145165/ | ||||||||||||||||||||
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Document Type: | Conference or Workshop Item (Speech) | ||||||||||||||||||||
Title: | Insights into surficial processes of pristine and coated magnesium anodes in magnesium-sulfur batteries | ||||||||||||||||||||
Authors: |
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Date: | 30 November 2021 | ||||||||||||||||||||
Refereed publication: | Yes | ||||||||||||||||||||
Open Access: | Yes | ||||||||||||||||||||
Gold Open Access: | No | ||||||||||||||||||||
In SCOPUS: | No | ||||||||||||||||||||
In ISI Web of Science: | No | ||||||||||||||||||||
Status: | Published | ||||||||||||||||||||
Keywords: | Magnesium-Schwefel Batterie, Magnesium-Sulfur, Artificial SEI, Electrochemical Impedance Spectroscopy, EIS | ||||||||||||||||||||
Event Title: | 12th Electrochemical Impedance Analysis (EIA) | ||||||||||||||||||||
Event Location: | Online | ||||||||||||||||||||
Event Type: | international Conference | ||||||||||||||||||||
Event Start Date: | 29 November 2021 | ||||||||||||||||||||
Event End Date: | 30 November 2021 | ||||||||||||||||||||
HGF - Research field: | Energy | ||||||||||||||||||||
HGF - Program: | Materials and Technologies for the Energy Transition | ||||||||||||||||||||
HGF - Program Themes: | Electrochemical Energy Storage | ||||||||||||||||||||
DLR - Research area: | Energy | ||||||||||||||||||||
DLR - Program: | E SP - Energy Storage | ||||||||||||||||||||
DLR - Research theme (Project): | E - Electrochemical Storage | ||||||||||||||||||||
Location: | Stuttgart | ||||||||||||||||||||
Institutes and Institutions: | Institute of Engineering Thermodynamics > Electrochemical Energy Technology | ||||||||||||||||||||
Deposited By: | Häcker, Joachim | ||||||||||||||||||||
Deposited On: | 06 Dec 2021 18:38 | ||||||||||||||||||||
Last Modified: | 24 Apr 2024 20:44 |
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