Electrolyte supported solid oxide fuel cells with the super large size and thin ytterbia stabilized zirconia substrate

In this work, the (ZrO2)0.95(Yb2O3)0.05(5YbSZ) electrolyte supported SOFCs with the large area of 10 cm × 10 cm and thin substrate of about 70 μm are prepared, and the microstructures, electrochemical and anti-redox properties of the single cells are investigated systematically. The powders of 5YbSZ with the tetragonal and cubic mixed phase are synthesized by the so-called “solid-liquid composite method” at a somewhat low temperature of 1100 °C. The 5YbSZ electrolyte substrates which are prepared by the tape-casting, multilayer-lamination and sintering method showed the optimal comprehensive performances with the sintering temperature being 1500 °C. By using these electrolyte substrates, the NiO+GDC/5YbSZ/LSM+5YbSZ single cells are obtained at the co-sinter temperature of 1100 °C. The power densities of these cells can reach 0.56 W cm−2 at the output voltage of 0.7 V, and the degradation rate can attain 1.45% kh−1 under a constant current density of 0.2 A cm−2 at the temperature of 830 °C. After 11 redox cycles, no crack through the 5YbSZ electrolyte can be found in the single cells, and the electrochemical properties of the 5YbSZ electrolyte supported single cells show an acceptable degradation.