Sensitivity Analysis of One-Dimensional Multiphysics Simulation of CO₂ Electrolysis Cell

Area of Science:

• Electrochemistry
• Chemical Engineering
• Materials Science

Background:

• Electrochemical (EC) carbon dioxide (CO2) reduction is vital for net-zero emissions, converting CO2 into valuable products.
• Simulations of EC cells are crucial for understanding operation, especially at short time and length scales where experimental data is limited.

Purpose of the Study:

• To construct and analyze a 1D simulation of a membrane-electrode-assembly EC cell for CO2 reduction.
• To investigate the impact of electrolyte conditions on cell performance.
• To perform a comprehensive sensitivity analysis of all input parameters, a novel contribution to the literature.

Main Methods:

• Developed a 1D simulation model for a membrane-electrode-assembly EC cell with a porous silver gas diffusion cathode.
• Simulated cell performance under various electrolyte conditions.
• Conducted a sensitivity analysis on all simulation input parameters to determine their impact on CO partial current density (iCO).

Main Results:

• The CO partial current density (iCO) is significantly influenced by all input parameters.
• Electrochemical kinetic parameters (i0/α) exhibit the highest sensitivity, with a 1% change in α causing up to a 6% change in iCO.
• Discrepancies between experimental and simulation results are likely due to parameter uncertainties.

Conclusions:

• Sensitivity analysis is a powerful tool for optimizing EC cell performance metrics like CO2 utilization and Faradaic efficiency.
• The study explains the wide variance in reported kinetic parameters (i0 and α) in the literature.
• Caution is advised when comparing experimental data with simulation results due to inherent parameter uncertainties.