Synthesis and long-term test of borosilicate-based sealing glass for solid oxide fuel cells

摘要

A series of borosilicate-based glasses, ternary BaO-SiO_2-B_2O_3 and quaternary BaO-SiO_2-B_2O_3-Al_2O_3 systems, are prepared as sealing materials for intermediate temperature solid oxide fuel cells (IT-SOFCs). The thermal expansion, crystalline phases, glass forming ability, and thcrmo-chemical stabilities of the glasses are characterized. Additionally, the effect of the B_2O_3/SiO_2 ratio and Al_2O_3 and BaO contents on the coefficient of thermal expansion (CTE) are discussed and compared. Test results show that one glass (G6) can fully wet various substrates at the scaling temperature of 1000 °C and match thermal expansion. Possible interfacial reactions between the glass and those cell components aging up to 5000 h are investigated by element mapping, XRD, SEM, and EPMA. Leakage testing was also performed at temperatures up to 650 °C. The results show that the glass (G6) remains amorphous after 5000 h test and is stable under these conditions and compatible with the other fuel cell components.