Team Technology of Solid Oxide Cells
The team is concerned with methods and materials for producing SOCs. A particular focus is placed on the relation between the materials and manufacturing or coating techniques, and the resulting physical, chemical, and electrochemical properties of the components and layers.
In addition, the activities for post-test analysis of cells and functional layers of operated stacks are concentrated in this team. The focus is on microstructural (SEM), optical (light microscopy, confocal microscopy, topography), physical (XRD, Raman) and chemical (wet chemistry, ZEA-3) analyses and investigations.
The main manufacturing and coating technologies to produce SOCs and stack functional layers are tape casting, screen printing and wet powder spraying. Depending on the layer requirements, however, dip and spin coating, plasma spraying, physical thin-film processes and electrophoresis are also available. Important development parameters are the physical powder properties (grain size, grain distribution, specific surface area), the recipes and the rheological properties of pastes, slips and suspensions, the machine parameters and the subsequent drying and sintering. In addition to the characterization methods available at IEK-1, such as rheometer, BET, grain size determination, (thermo)mechanical characterization at IEK-2, electrochemical characterization at IEK-9 and high-resolution microscopy at ERC can also be used.
The post-examination of operated stacks is carried out together with the other institutes involved in Jülich’s SOC development. The main focus of the IEK-1 post-examination is on the cells and the contact and protective layers. Material-specific changes, foreign phase formations, interactions and interdiffusions as well as micro- and macrostructural changes are recorded, characterized, evaluated and related to the operating parameters (T, t, current density, humidity, etc.).
Highlights of the last few years include a Mn-Al-containing foreign phase formation after prolonged SOFC operation described for the first time (https://doi.org/10.1016/j.jpowsour.2017.11.025), Ni outward migration in the fuel gas electrode in SOEC operation (10.1149/2.0961805jes) and the comparatively minor changes within the cell after extremely long operation (https://doi.org/10.1016/j.jpowsour.2020.228770).