Development of glass sealants for proton conducting ceramic cells: materials, concepts and challenges

In this study, we have successfully developed and tested sealing concepts for symmetrical, planar proton-conducting ceramic cells (PCCCs). Three glass sealants from the field of solid oxide cells were investigated as potential compatible sealing materials for PCCCs. The most promising results were obtained with a SiO₂-MgO-CaO-Na₂O-Al₂O₃-ZrO₂-B₂O₃ glass, which provided a dense, crack-free sealant between the proton-conducting ceramic cells and the Al₂O₃-coated ferritic steels. During the sealing process, a reaction layer between the interface of the BaCe_0.2Zr_0.7Y_0.1O_3-δ contained in the PCCCs and the glass–ceramic, occurred. Here, we propose a reaction mechanism for this interaction and discuss its impact on potential applications. Moreover, next to evaluating potential glass sealants, we have successfully designed and demonstrated a new sealing geometry that prevents a potential gas crossover in the symmetrical proton-conducting ceramic cell.