Scaling CO₂ Electrolyzer Cell Area from Bench to Pilot.

Area of Science:

• Electrochemistry
• Chemical Engineering
• Materials Science

Background:

• Scaling up CO2 electrolyzer technology is essential for reducing carbon dioxide emissions.
• Current bench-scale electrolyzers (<5 cm²) require significant scaling (100s-1000s cm²) for industrial viability.

Purpose of the Study:

• To investigate the impact of increasing CO2 electrolyzer cell area on performance.
• To identify key factors limiting performance during scale-up.
• To develop strategies for maintaining selectivity and efficiency in larger-scale electrolyzers.

Main Methods:

• Studied CO2 electrolyzer performance across two orders of magnitude in cell area (5 cm² to 800 cm²).
• Instrumented an 800 cm² cell to diagnose performance losses.
• Redesigned the 800 cm² cell focusing on compression uniformity and CO2 transport.

Main Results:

• Directly scaling a 5 cm² cell design to 800 cm² resulted in a ~20% drop in ethylene selectivity and increased hydrogen evolution.
• Nonuniform electrode compression and flow-influenced CO2 availability were identified as primary performance limitations.
• Redesigning the 800 cm² cell for improved compression tolerance and CO2 transport restored hydrogen evolution efficiency comparable to the small-scale cell.

Conclusions:

• Uniform electrode compression and optimized fluid flow are critical for successful CO2 electrolyzer scale-up.
• CO2 electrolyzer area can be scaled over 100-fold while retaining high ethylene selectivity.
• This work provides a pathway for industrial-scale CO2 electrolysis for emissions reduction.