Early Warning for the Electrolyzer: Monitoring CO2 Reduction via In‐Line Electrochemical Impedance Spectroscopy

• Published in: ChemSusChem Vol. 16; no. 23; pp. e202300657 - n/a
• Main Authors: Warkentin, Hugh, O'Brien, Colin P., Holowka, Sarah, Maxwell, Benjamin, Awara, Mariam, Bouman, Mark, Zeraati, Ali Shayesteh, Nicholas, Rachael, Ip, Alexander H., Elsahwi, Essam S., Gabardo, Christine M., Sinton, David
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 07-12-2023
• Subjects: Carbon dioxide; carbon dioxide conversion; Chemical industry; Chemical reduction; Degradation; electrocatalysis; Electrochemical impedance spectroscopy; electrochemistry; energy conversion; Failure; Failure modes; Initial conditions; Membranes; Monitoring; Parameter identification; Short circuits; Spectrum analysis
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.202300657

The electrochemical CO2 reduction reaction (CO2RR) to fuels and feedstocks presents an opportunity to decarbonize the chemical industry, and current electrolyzer performance levels approach commercial viability. However, stability remains below that required, in part because of the challenge of probing these electrolyzer systems in real time and the challenge of determining the root cause of failure. Failure can result from initial conditions (e. g., the over‐ or under‐compression of the electrolyzer), gradual degradation of components (e. g., cathode or anode catalysts), the accumulation of products or by‐products, or immediate changes such as the development of a hole in the membrane or a short circuit. Identifying and mitigating these assembly‐related, gradual, and immediate failure modes would increase both electrolyzer lifetime and economic viability of CO2RR. We demonstrate the continuous monitoring of CO2RR electrolyzers during operation via non‐disruptive, real‐time electrochemical impedance spectroscopy (EIS) analysis. Using this technique, we characterise common failure modes ‐ compression, salt formation, and membrane short circuits ‐ and identify electrochemical parameter signatures for each. We further propose a framework to identify, predict, and prevent failures in CO2RR electrolyzers. This framework allowed for the prediction of anode degradation ~11 hours before other indicators such as selectivity or voltage.
Advanced failure warning: Combining in‐line real‐time multi‐sine electrochemical impedance spectroscopy with selectivity and voltage data builds a framework for stable electrolysis enabling early failure detection and prevention.