Investigation of salt precipitation and water management in zero‐gap CO₂ electrolyzers producing CO : = Investigation of salt precipitation and water management in zero‐gap CO2 electrolyzers producing CO

Abstract: Using CO₂ as renewable feedstock to replace fossil-based carbon sources for the production of feedstock chemicals and fuels is a pivotal cornerstone for the defossilization of hard-to-decarbonize sectors like the chemical industry or aviation. A promising approach for the conversion is the electrochemical reduction of CO₂, which allows the production of various bulk chemicals like carbon monoxide (CO), formic acid and ethylene only from CO₂, water and electricity. However, industrial employment of that technology is currently mitigated by low energy efficiency, low product selectivity and rapid performance degradation.
The scope of this thesis is the investigation of lifetime-limiting processes in CO₂ electrolysis cells producing CO and the development of strategies to overcome these limitations. For that, a test bench for the electrochemical characterization of zero-gap CO₂ electrolysis cells is designed and put to operation. State-of-the-art performance is established with this setup, achieving 200 mA cm−2 at a cell voltage of 2.8 V with a selectivity for CO of ≈99 %.
In the second step, water management and salt precipitation, both major hurdles
for stable long-term operation, are investigated with high-resolution neutron imaging. The measurements with a high spatial resolution of ≈6 μm, show that the cathode electrode gets drier with increasing current density, while salt precipitation is boosted. Significant differences between cathode flow field channel and land regions were uncovered, suggesting that the influence of cell compression and flow
field design should be investigated in future studies.
Subsequently, an extensive literature review is conducted to identify strategies to
mitigate the rapid performance degradation caused by salt precipitation. The influence of operating conditions and material properties on the formation of salt precipitates are discussed in detail and the effectiveness of various strategies is compared

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• Alternative title: Investigation of salt precipitation and water management in zero‐gap CO2 electrolyzers producing CO
• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch
• Notes: Universität Freiburg, Dissertation, 2024

Contributors, Places and Time

• Event: Veröffentlichung
• (where): Freiburg
• (who): Universität
• (when): 2024
• Creator: Disch, Joey
• Contributor: Vierrath, Severin ; Krossing, Ingo ; Zengerle, Roland ; Albert-Ludwigs-Universität Freiburg. Institut für Mikrosystemtechnik ; Albert-Ludwigs-Universität Freiburg. Professur für Anwendungsentwicklung ; Albert-Ludwigs-Universität Freiburg. Fakultät für Angewandte Wissenschaften

Further information

• DOI: 10.6094/UNIFR/244204
• URN: urn:nbn:de:bsz:25-freidok-2442041
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.