Electrolyte Layer Gas Triggers Cathode Potential Instability in CO2 Electrolyzers

Published

February 1, 2021

Author(s)

Kevin Krause, Jason K. Lee, ChungHyuk Lee, Hisan W. Shafaque, Pascal J. Kim, Kieran F. Fahy, Pranay Shrestha, Jacob LaManna, Elias Baltic, David Jacobson, Daniel Hussey, Aimy Bazylak

Abstract

Electrolytic carbon dioxide (CO2) reduction is becoming increasingly promising for managing anthropogenic CO2 emissions; however, issues related to unstable performance and ineffective gas management are still not fully accounted for in the field. Here, we identify two instability modes that are directly linked to the electrolyte layer gas saturation for an anion exchange membrane flow cell circulating KHCO3. The cathode potential exhibits a semi-stable mode with low electrolyte layer gas saturations and a detrimental secondary mode with high gas saturations and a highly noisy, non-stationary potential. We illustrate that the gas saturation has a profound, direct impact on the mode of instability with a direct correlation between the coefficient of variation in cathode potential and the electrolyte layer gas saturation measured with real-time neutron radiography. This correlation is indicative of reaction site gas blockage that results in performance instability and reduced energy efficiency.

Citation

Journal of Power Sources

Pub Type

Journals

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Keywords

Gas management, CO2 reduction, cathode potential instability, gas bubbles, liquid electrolyte, neutron radiography

Citation

Krause, K. , Lee, J. , Lee, C. , Shafaque, H. , Kim, P. , Fahy, K. , Shrestha, P. , LaManna, J. , Baltic, E. , Jacobson, D. , Hussey, D. and Bazylak, A. (2021), Electrolyte Layer Gas Triggers Cathode Potential Instability in CO2 Electrolyzers, Journal of Power Sources, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=933236 (Accessed March 15, 2025)