Comprehensive modeling of solid oxide electrolyzer cells for H2O and CO2 co-electrolysis

Abstract

In this study, a 2D model of Solid Oxide Electrolysis Cells (SOECs) was developed to evaluate their performance in CO2 and H2O co-electrolysis. The numerical results were rigorously validated against prior studies, demonstrating high consistency. The investigation focused on understanding the influence of various factors such as support type and operating temperature on SOEC performance.Analysis of polarization and performance curves revealed that anode-supported and cathode-supported SOECs exhibited similar characteristics, while electrolyte-supported SOECs displayed lower performance due to inadequate conductivity and increased electrolyte thickness. At 1.6 V, the average current density for cathode-supported SOEC was approximately 2.3679 A/cm², slightly lower than that of anode-supported SOEC, which was approximately 2.3879 A/cm². Moreover, at an average current density of around 5.30 A/cm², the cathode-supported SOEC yielded an average power density of 10 W/cm², while the anode-supported SOEC achieved 10.1 W/cm².Furthermore, increasing temperature was found to enhance SOEC performance by promoting more efficient chemical reactions, reducing resistance, and improving gas production rates during electrolysis of H2O and CO2. However, careful consideration of optimal operating temperatures is essential to ensure cell durability and material lifespan.Moreover, comparing co-flow and cross-flow configurations highlighted minor differences in performance, with co-flow demonstrating slightly lower average current density but comparable power density at 1.6 V. Co-flow configuration was favored for its homogeneous operation, facilitating efficient gas mixing and diffusion, while counter-flow configurations may introduce heterogeneity, potentially affecting overall performance.Overall, this study provides valuable insights into optimizing SOEC performance and efficiency, emphasizing the importance of support type, operating temperature, and flow configuration in achieving optimal performance for CO2 and H2O co-electrolysis applications.