1. Introduction
The development of solid oxide fuel cells (SOFCs), which have undoubtedly
a great potential as electric power generation systems, is
still prevented by cost, which is several times higher than required for
economic feasibility, and by insufficient durability [1–10].
Mainly the high operating temperature (850 °C or higher) of the
widely used yttria stabilized zirconia is the reason for the lack of practical
application of the SOFCs so far. Problems like cell sealing and thematerials
used for this purpose lead to long heating up and cooling down
times. Another drawback is the accelerated degradation of metallic
parts used in the system. Improved cell and further system reliability
could be achieved by decreasing the operating temperature to values
lower than 800 °C [5–14].
Intermediate temperature (IT) SOFCs demand on the other hand
electrolytes with higher ionic conductivity like e.g. Ce0.8Gd0.2O1.9