Feldspar-based CaO–K2O–Na2O–BaO silicate glass sealant for solid oxide fuel cells

Sealants have been widely used in solid oxide fuel cells (SOFCs), and glass sealants have shown considerable potentials due to their low leakage rate. We report a type of feldspar-based glass sealant, mainly composed of CaO–K2O–Na2O–BaO, with a coefficient of thermal expansion (CTE) of 10.11 × 10−6 k−1, a glass transition temperature at 528 °C, and a softening temperature at 573 °C. Using this sealant to seal anode-supported SOFCs, the open-circuit voltage (OCV) remains at 1.08 V after five thermal cycles and 50-h aging at 750 °C, close to the theoretical OCV value. The SEM and EDS reveal stable interface between the glass sealant and the anode, indicating excellent performance of the CaO–K2O–Na2O–BaO glass sealant for SOFC sealing applications.