Proton-conducting electrolysis cells (PCECs) are critical to sustainable energy technologies, as they enable the production of undiluted hydrogen that can be readily compressed and stored. These cells are essential for establishing a hydrogen economy. However, their fabricationpresents significant challenges compared to more established technologies, such as oxygen ion conducting solid-oxide cells, necessitating advancements in both material and process technologies. They are more challenging to develop because the material system on which proton-conducting cells are based—solid solutions of Y, Yb-substituted barium cerate and barium zirconate (BZCY)—is chemically more complex than the Y-stabilized ZrO2 used for oxygen ion conduction. This complexity arises from the less-characterized fundamental properties of these materials, which still pose significant questions regarding basic processing and material behavior. To ensure the PCECs potential is realized, scalable manufacturing processes adapted to this material system are needed to transition laboratory-scale innovations into industrially relevant applications. This thesis focuses on enhancing robustness, scalability, and reliability in the manufacturing of proton-conducting electrolysis half-cells, based on BZCY-721 electrolytes on a Ni/BZCY-721 cermet as hydrogen electrode and mechanical support. Central objectives include improving the success rate of sintered half-cells, refining the quality of green bodies through optimized slurry composition and tape casting, mitigating warpage, and gaining a deeper understanding of material sintering behavior. Several challenges were addressed, such as batch-to-batch variations in powder properties, the destabilizing effects of methyl ethyl ketone (MEK) as a solvent, and the refractory nature of Zr-rich BZCY materials. Tailored solutions were implemented to achieve dense, flat, and crack-free half-cells (sizes ranging between d = 20 mm and 2.5 × 5 cm2) along with optimized sintering setups to improve layer density and structural integrity. Significant achievements were made during this work. At the outset, the fabrication process yielded no usable cells, with issues such as warpage, cracking, and insufficient density. By the end of the research, green body defects were reduced to approximately 10 % through improvements in slurry preparation, tape casting, and cutting techniques. Post-sintering success rates increased up to 80 %. Additionally, a deeper understanding of the sintering behavior of individual layers provided insights into mismatches between hydrogen electrodes and electrolytes, as well as heating rate-dependent sintering mechanisms. These findings facilitated the mitigation of warpage which then eliminated the need for post-sintering flattening or laser cutting steps. The scalable methods developed in this thesis enable the production of reproducible cells, which are essential for systematic investigations into material dependencies and performance characteristics. This reproducibility supports crucial research into degradation mechanisms, long-term stability, and full-stack testing, advancing the practical application of protonconducting electrolysis cells. Furthermore, shrinkage rate measurements revealed a complex chain of sintering mechanisms, likely contributing to the limited processability of these cells. Future research should focus on elucidating these mechanisms in greater detail and adapting sintering schedules accordingly. On the application side, scalable production processes ensure that future studies into performance under various operational atmospheres and the optimization of steam electrode materials can be conducted with consistent and comparable cell quality. A noteworthy aspect of this thesis is the conscious decision to document failed experiments.This approach provides valuable insights for future researchers, helping to avoid similar pitfalls and refine their processes. By addressing both fundamental material challenges and practical production issues, this thesis represents a significant step forward in the development ofscalable and robust production methods for proton-conducting electrolysis cells, bringing the field closer to integration into real-world energy systems.
Laura‐Alena Schäfer (Wed,) studied this question.