Squeezing Gas Diffusion Electrodes in Zero-Gap CO₂ Electrolyzers─Enough Is Enough

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Electrochemical reduction of carbon dioxide to carbon monoxide (CO2RR) is nearing industrial application.
• Scaling up CO2RR technology requires understanding component behavior and challenges at larger sizes.

Purpose of the Study:

• To investigate the impact of cathode gas diffusion electrode compression ratio on CO2RR performance.
• To analyze how different carbon-based cathode supports respond to varying compression.

Main Methods:

• Electrochemical impedance spectroscopy was used to analyze performance changes.
• Microtomography measurements provided insights into structural alterations.
• Cathodes were compressed to less than 40% of their original thickness.

Main Results:

• Optimal compression range is dependent on the specific gas diffusion layer properties.
• A broad optimal compression range (60-85% original thickness) was identified for the ELAT1400W gas diffusion layer.
• Performance was confirmed over 100-hour experiments.

Conclusions:

• Cathode compression is a critical parameter for optimizing CO2RR systems.
• Tailoring compression to gas diffusion layer characteristics is essential for efficient and durable CO2 electrolysis.
• The findings provide guidance for scaling up CO2RR technology.