Mass and thermal management strategies for MEA-based CO₂ electrolyzers enabled by physics-based modeling

Membrane electrode assembly (MEA)-based CO₂ electrolyzers are promising for electrochemical CO₂ reduction (CO₂R) due to their compact design and high current densities. However, performance and durability are often limited by mass transport constraints, thermal gradients, and salt precipitation. We present a comprehensive, non-isothermal, physics-based model that captures multiphase transport of gaseous, liquid, and ionic species, coupled with heat generation, electrochemical reactions, and phase transitions within an MEA-based CO₂ electrolyzer. This model predicts key performance indicators, including CO faradaic efficiency, energy and mass conversion efficiencies, electrode flooding, and salt precipitation. Simulation results identify optimal operating strategies: cathode-side cooling at 10 °C, elevated pressure at 8 atm, and anode-side heating at 80 °C, collectively improving energy efficiency by 42.4% compared to baseline conditions. These findings underscore the importance of precise thermal and mass transport management in advancing scalable CO₂ electrolyzer technologies.