Reduced-temperature hermetic sealing of planar SOFC using Zn-containing borosilicate glass modified with Ni-Co spinel oxide

Zn-containing borosilicate glass-ceramic sealant is developed for LT-SOFCs. • ZnO enables a low softening temperature (~600 °C) and controlled crystallization. • Small additions of Ni-Co spinel oxide effectively strengthens the seal. • Ultra-low leakage rate of 0.0023 sccm cm −1 is maintained for 1350 h at 700 °C. • Strong interfacial bonding and minimal elemental interdiffusion ensure durability. SOFCs are attractive energy conversion devices due to high efficiency and fuel flexibility, but commercialization is limited by sealing reliability. Glass sealants must provide gas tightness, thermal expansion compatibility, mechanical robustness, and chemical stability at reduced operating temperatures. This study develops a Zn-containing borosilicate glass-ceramic modified with Ni-Co spinel for reduced-temperature planar SOFCs. ZnO lowers the softening temperature (~600 °C) and controls crystallization while maintaining CTE compatibility. The optimized seal shows hermeticity with leakage of ~0.005 sccm cm −1 over ten thermal cycles. Incorporation of 1 wt% Ni-Co improves stability, reducing leakage to 0.0023 sccm cm −1 over 1350 h at 700 °C. Thermal analysis shows Ni-Co affects intrinsic thermal properties but moderates glass fluidity, suppressing excessive flow. Microstructural and interfacial analyses confirm adhesion to YSZ and NiCo 2 O 4 -coated stainless-steel, with limited interdiffusion and no harmful reaction layers. Overall, the Zn-containing Ni-Co-modified glass-ceramic is a durable sealing solution for reduced-temperature SOFC applications. Download: Download high-res image (257KB) Download: Download full-size image