Modeling of multiple-defect conducting, planar protonic ceramic electrolysis cells using a Nernst-Planck formulation

Advancing protonic ceramic electrochemical cell (PCEC) technology offers promise for a variety of energy applications, including membrane reactors, fuel cells, and electrolyzers. Computational modeling of PCECs requires tracking the movement of three mobile charge carriers: protons, oxygen vacancies, and small polarons to adequately predict the cell operating characteristics. This paper develops an experimentally validated, quasi2D (1 + 1D), transient, dual -channel cell model based on a multiple -charged defect -conducting electrolyte. The new model advances predictive capabilities on a number of fronts. First, it reduces empiricism, simplifies integration of experimentally derived modeling parameters, and enables rapid model scale -up to large cell platforms. Additionally, it predicts the distribution of properties in the streamwise gas flow direction and cell faradaic efficiency over a wide range of operating cell conditions helping to establish the inlet gas conditions needed to produce a dry hydrogen product gas. Model simulation reveals that the evolution of steady-state, thermal -neutral voltages in a PCEC can significantly change from initial operating values due to a dynamic, complex interaction which arises from local decreases in faradaic efficiency. Insights from modelbased performance predictions touch upon thermal management considerations and the means for regulating cell temperature when trying to achieve either adiabatic or quasi -isothermal PCEC operation.