Improvement of thermal cycle stability of YSZ-glass composite seals for intermediate temperature solid oxide fuel cell

Abstract

Glass ceramic seals have been widely used in solid oxide fuel cell (SOFC). However, the sealing performance of seals is a big challenge for SOFC operating at high temperature. In this work, the gas tightness, chemical compatibility and thermal cycle stability of the glass-based seals with various proportions of YSZ and glass are evaluated and discussed. The study showed that when 20 wt% YSZ is added to H4 glass, the as-prepared glass ceramic seal (denoted as H4-20) exhibited extremely low leakage rate of 0.00171 sccm cm−1 under input pressure of 20.7 kPa and wide temperature range from 650°C to 800°C. In addition, the leakage rate of H4-20 glass ceramic seal below 0.004 sccm cm−1 was obtained after 10 thermal cycles at 750 °C. The SEM analysis indicated that the H4-20 glass ceramic seal could form well bonding interface between the interconnect/seal/cell. The above results prove the possibility of the H4-20 glass ceramic seals to be considered for intermediate temperature SOFC application.