Guest lecture by Dr. Sandrine Ricote| Recent progress and challenges in protonic ceramic electrolysis cells

Abstract: Over the past four decades, protonic ceramics have captivated increasing attention, with a notable surge in interest observed in recent years. This trend can be explained by a better understanding of their properties and the development of scalable and reproducible manufacturing processes. This presentation will begin with a comprehensive overview of protonic ceramics, specifically emphasizing their conductivity and hydration properties. Subsequently, it will delve into the diverse applications of protonic ceramic cells, encompassing fuel cells, electrolyzers, and membrane reactors.

The core of the presentation will revolve around electrolysis cells (protonic ceramic electrolysis cells, PCECs), with an initial focus on the latest advancements in the field. Following this, the major challenges and corresponding solutions will be addressed: (1) The faradaic efficiency, which is proportional to the ratio of the net hydrogen molar flux over the imposed current density, is an important performance metric: the discrepancy in the results in the literature and potential solutions to achieve high faradaic efficiencies will be discussed. (2) The steam electrode (positrode) mechanisms are more complex than in solid oxide electrolysis cells, and the community is working on developing highly performant materials at intermediate temperatures. In addition, the positrode materials must also be stable under high steam contents.