Sampling dynamics for pressurized electrochemical cells

A model describing the gas distribution within a constant pressure electrolysis system and how the distribution impacts electrochemical efficiencies is presented. The primary system of interest is the generation of syngas (CO and H-2) associated with the co-electrolysis of H2O and CO2. The model developed for this system takes into account the primary process variables of operation including total system pressure, applied current, and the in-flow of reactant gases. From these, and the chemical equilibria within the system, the impact on electrochemically generated gases is presented. Comparison of predicted and measured faradaic efficiency of an electrode's processes reveals significant disagreement under certain conditions. Methods to minimize and account for the discrepancy are presented with the goal of being able to discern, in a real-time manner, degradation of electrode performance. Comparison of the model to experimental data shows a strong correlation between the two with slight variation in experimental data, which is attributed to reversible system dynamics such as wetting of the gas diffusion electrode used as the cell cathode.