Effective ceramic sealing agents for solid oxide cells by low temperature curing below 200 °C

Crystallized glass as a sealing agent for high-temperature solid oxide cells (SOCs) such as fuel cells and electrolyzers must first be melted at a high temperature and vitrified. Such high temperature can cause stress due to thermal expansion. The applicability is evaluated for ceramic sealing agents (CSAs) that do not require a hightemperature melting treatment and that can exhibit sealing properties by low temperature curing at 180 degrees C. In the evaluation of the bulk body of the CSAs, there is no change in physical properties and performance in a wide temperature range between a low temperature for curing and a high temperature for SOC operation. Moreover, in the CSA adhesion test with SUS430, almost no gas leakage occurs even after 150 heat-cycles (each cycle was 1 h at room temperature followed by 1 h at 800 degrees C) by optimizing the thermal expansion coefficient of the CSA. An SOC using the CSA as gas sealing material exhibits almost the same open-circuit voltage as the theoretical value and shows a stable fuel cell operation for 100 h without degradation. These results indicate that CSAs can be a candidate for the sealing material of SOCs in a wide temperature range.

Automated summary

The research finds that ceramic sealing agents exhibit stable sealing properties in a wide temperature range for high-temperature solid oxide cells, with the characteristics of low-temperature curing and optimized thermal expansion coefficient, making them suitable candidates for SOC sealing materials.