Design and characterization of novel glass‐ceramic sealants for solid oxide electrolysis cell ( SOEC ) applications

Abstract In this work, three new glass‐ceramic compositions are designed and characterized as sealant materials for solid oxide electrolysis cells ( SOEC ), having operating temperature of 850°C. The crystallization and the sintering behavior of the glasses are investigated by using differential thermal analysis ( DTA ) and heating stage microscopy ( HSM ) respectively. The glasses show glass transition temperatures of 715‐740°C, while the coefficients of thermal expansion ( CTE ) of 9.3‐10.3 × 10 ⁻⁶ K ⁻¹ (200‐500°C) are measured for the glass‐ceramics, matching with the CTE s of the other cell components. The compatibility between the glass‐ceramic sealants, the 3 YSZ electrolyte and the Crofer22 APU interconnect is examined by means of SEM and EDS , in the as‐joined condition and after 1000 hours at 850°C in air. Compositional changes in the glass‐ceramic sealants are reviewed and discussed with respect to the formed crystalline phases before and after the aging treatment at 850°C.