Low-temperature glass sealants for protonic ceramic electrolysis cells

Overview

Politecnico di Torino has developed innovative borate-based glass sealants designed specifically for the integration of protonic ceramic electrolysis cells (PCECs). These sealants are essential for creating reliable, gas-tight stacks by joining ferritic stainless steel interconnects to proton-conducting ceramic half-cells. By enabling low-temperature joining, these materials help mitigate interfacial reactivity while ensuring the necessary thermomechanical stability for long-term operation. This research addresses a critical challenge in the development of PCEC technology, facilitating the transition of these high-efficiency systems from laboratory experiments toward scalable, practical applications.

Technical specifications

• Composition: Based on B2O3–BaO–Al2O3–CaO–SrO–SiO2 and B2O3–BaO–SiO2–Al2O3–CaO–SrO–ZnO–ZrO2 systems.
• Processing: Tailored for low-temperature joining at temperatures below 700 °C.
• Performance: Exhibits excellent gas-tightness with helium leakage rates below 1 x 10^-9 mbar L s^-1.
• Compatibility: Demonstrates strong chemical adhesion and thermomechanical compatibility with NiO-SZCY541/BZCY442 half-cells and AISI 441 stainless steel interconnects.
• Fabrication: Suitable for deposition using screen-printed tapes to form uniform, stable seals with a thickness of approximately 200 μm.

Technology readiness level

The technology is at level 4. The research has successfully demonstrated the design, processing, and testing of these sealants at a laboratory scale, including successful integration in symmetric metal/glass/metal and asymmetric ceramic/glass/metal assemblies with optimized joining parameters. Further development is required to scale this technology to full-stack, industrial-level commercial deployment.