Validation of and Simulations using a High-Temperature Electrolysis Model

A continuum mechanistic, real-scale model with the most important reactions of high-temperature electrolysis is proposed. IV-characteristics and impedance spectra serve as comparison to experimental data for steam, CO 2 and co-electrolysis. The exchange current-density i 0 can be determined to the same order of magnitude as observed in experiments for steam electrolysis. The IV-characteristics for CO 2 electrolysis are well described by an i 0 one order of magnitude lower as compared to steam electrolysis. Parameter variations identify contributing variables determining the shapes of characteristics. Limitations in prediction are revealed for low current densities up to 0.5 A∙cm -2 . EIS calculations demonstrate the dominant behavior of charge transfer or oxygen ion incorporation into the lattice as function of i 0 or temperature. The model forms a solid basis for various future investigations like a more detailed reaction system with possible intermediates or degradation and poisoning effects.