Development of flexible ceramic-glass seals for intermediate temperature planar solid oxide fuel cell

• A flexible ceramic-glass composite seals was developed by tape casting technique.
• The optimized AD40 composite seals demonstrated an excellent gas tightness and deformability.
• The cell used AD40 seals maintained high performance and low degradation rate.

The ceramic-glass was employed as the most commonly used seal materials in planar solid oxide fuel cell (SOFC). In this study, a novel glass with relative low glass soft temperature was added into Al2O3 powders to form ceramic-glass composite seals by tape casting technique. Based on the tested result of gas tightness and compressibility, it was found that the seals with 40 wt% glass exhibited excellent seal performance at the leakage rates of only 0.01 sccm.cm−1 under gas pressure of 10.2 kPa, and compressive load of 0.17 MPa at 750 °C. The seals showed the desired thermal cycle stability at low leakage rates within 10 thermal cycles. It can be observed that the deformability of seals sharply increase when the glass contents was higher than 30 wt%. Microstructural analysis of the seals also exhibited very good interfaces bondage and chemical compatibility which was in good agreement with gas tightness prediction for the flexible ceramic-glass seals model. The seals have been applied in large size cell test to confirm its applicability in SOFC.