1D/2D Solid Oxide Electrolyzer Degradation Modeling

High-temperature steam electrolysis represents an efficient and sustainable method for producing hydrogen and can play a pivotal role in the transition toward clean energy sources. However, in the current scale-up to the Gigawatt scale long-term durability of the technology remains to be assessed. In this frame, this thesis focuses on developing a semi-empirical model that describes the degradation mechanisms at stack level. The complex multilayer system based on solid oxide ceramic materials is quite challenging to model at cell, single repeating unit, and at stack level. Thus, the aim of this thesis is to achieve at first a 1D/2D model that describes appropriately the stack behavior. Based on the extended literature, a model is developed on MATLAB based on a combination of thermal and electrochemistry equations from the literature to provide insights into the behavior of the voltage distribution across the stack, the temperature gradient, and area-specific resistance. Further, an analysis of different factors is carried out such as the variation of the thickness of specific components, current density and performance, and their impact on cell performance. These factors can contribute to issues such as second-phase formation, delamination, and element diffusion; all these phenomena are implemented in an additional empirical resistance variable with temperature and time. Then, the prediction of the degradation rate is implemented by calibrating the base case with experimental data in order to obtain a simulation of the temperature and voltage evolution with time. The semi-empirical model developed herein is the first basis for a more complex analysis of diverse operating conditions and stack configurations.