Joint project SOC-Degradation 2.0: Transfer of knowledge into products for a "Green Hydrogen" vector - Impedance analysis of intrinsic and extrinsic degradation mechanisms in SOC cells and repeat units

Electrolyzers and fuel cells based on solid oxide electrolytes (SOEC, Solid Oxide Electrolysis Cell, or SOFC, Solid Oxide Fuel Cell) enable the highest efficiencies compared to alkaline and PEM systems. Therefore SOC technology represents a promising approach for the production of green hydrogen and the generation of electricity and heat in CHP plants. With regard to the use of SOC technology, especially for hydrogen production but also for power generation, the lifetime and robustness of fuel cell stacks still represent a hurdle. The aim of the project SOC-Degradation 2.0 is to create an experimental and scientific basis for the predictive understanding of degradation phenomena in SOC stacks and systems.

The IAM-ET is involved in the subprojects Impedance Analysis, Contaminants in Gases, and Electrolysis and Reversible Operation. Impedance measurements on cells and repeat units under system-relevant operating conditions, feasible in the IAM-ET test benches, will be used to investigate the effects of intrinsic (caused by materials and interfaces in the cell and repeat unit) and extrinsic (caused by contaminants in the supplied gases) degradation mechanisms and to evaluate countermeasures. Impedance analysis approaches as the distribution of relaxation times (DRT) in combination with physicochemical impedance models, developed at IAM-ET, provide quantitative information on aging of individual cell components, enables the evaluation of different approaches to increase lifetime of cells and stacks and increases reliability assurance for cells and stacks.