Development of Al_2O_3/glass-based multi-layer composite seals for planar intermediate-temperature solid oxide fuel cells

摘要

In this paper, the novel multi-layer composite seals for planar solid oxide fuel cells are studied. The composite seals with sandwiched structure include Al_2O_3-based tape as support and glass-ceramic slurry as binder connecting the interface of the neighboring components. The result finds out that glass-ceramic slurry with 20 wt% Al_2O_3 has the suitable strength and deformability. The thermal cycle characteristics are greatly improved by using the multi-layer composite seals, and the corresponding leakage rates are lower than 0.025 seem cm~(-1) for 20 thermal cycles at the inlet pressure ranging from 0.5 psi to 2 psi. SEM investigations show a very compact and good adhesion between the neighboring components, which can minimize the leakage paths. Single cell testing is used to examine the performance of the seals. The value of open circuit voltage is 1.17 V. At the constant discharge current density of 0.37 A cm~(-2), the voltage is stabilized at about 0.85 V for 50 h. The results demonstrate that the novel multi-layer composite seals are good candidate for SOFC application.