[THESIS DEFENSE] - RM2I - Raphaël Voivenel

SOCs, Glass seal, Self-healing,

Hydrogen is a chemical and energetic carrier, that offers a renewable alternative to fossil fuels. The electrolysis of water powered by renewable electricity meets this condition and makes it possible to envisage the massive decarbonization of energy systems. To ensure a hydrogen cost compatible with its use in industry or transport, key R&D priorities focus primarily on the durability and cost of the ceramic electrochemical cells at the heart of EHT technology. As part of the France 2030 investment plan, the objective of the CELCER-EHT project, within which this study is conducted, is to develop the various constituent materials of an anionic-conducting ceramic cell that are durable, efficient, and low-cost. This work focuses on the sealing of the cell through the development of seals. Several types of glass seals are reported in the literature, compressed, brazed and glass. These have proven to be the most promising due to their chemical stability in the different environments of SOCs. Two types can be distinguished: compliant and rigid. Compliant seal shows a lower sealing temperature but a lower chemical stability compared to rigid seals. However compliant seals are widely used due to their easier shaping. This work focuses on the formulation of glass matrices and the development of new shaping techniques for rigid seals. The synthesized seals were studied for up to 960 hours at the cell’s operating temperature (800 °C) using XRD and NMR. The evolution of the glass–metal interface during aging was examined by SEM-EDX, as well as its self-healing capacity at high temperature.