Model-based optimization of solid oxide electrolysis cells and stacks for powerto- gas applications

Power-to-Methane (PtM) is an attractive chemical storage concept enabling the coupling of intermittent renewable energy sources with the gas grid. Here, we use a combined experimental and modeling methodology to investigate and optimize solid oxide electrolysis cells (SOECs) and stacks operation for PtG applications. Firstly, electrode- and electrolyte-supported single cells from commercial suppliers are characterized in terms of their electrochemical performance and their microstructure. By implementing the structural data into a detailed single cell model and by reproducing steady-state polarization curves, the model is calibrated and validated for both cell designs. Subsequently, 2D adiabatic simulations are conducted to examine the performance of both cell types in detail. Afterwards, a scale-up to the 3D stack level is performed to correlate the model-predicted stack performance with that of a single repeating unit, which illustrates the implications of scaling-up on the SOEC performance. These analyses can provide valuable guidelines for cell and stack design considerations for PtM applications.