Scaling of CO ₂ -to-CO Membrane Electrode Assembly Cell: From 5 cm ² Single Cell to 300 cm ² Stack

Translation of electrochemical carbon dioxide (CO 2 )-to-carbon monoxide (CO) conversion in membrane electrode assembly cells to industrially relevant dimensions and robustness remains constrained by issues, such as cathode flooding, salt formation, and electrode degradation at elevated current densities. Through scaling from a 5 cm 2 cell to a 300 cm 2 stack, we address three specific challenges: (i) uniform dispersion of fluorinated ethylene propylene with in the Ag cathode prevents flooding; (ii) baffled serpentine flow fields accelerate liquid removal from gas diffusion layers; and (iii) corrosion-resistant IrO 2 -coated dimensionally stable anode replaces the carbon-based anode to ensure stable oxygen evolution. The optimized 100 cm 2 cell sustains a 95.2% CO selectivity at 30 A with minimal voltage drift. A 300 cm 2 stack achieves 89.8% CO selectivity at 90 A, producing 25.1 mmol of CO min –1 . In aggregate, these results address key challenges related to translation of CO 2 -to-CO electrolysis from laboratory- to pilot-scale.