Perovskite materials for intermediate temperature solid oxide fuel cells cathodes: A review

Solid oxide fuel cells (SOFC) have high efficiency compared to modern thermal power plants. Moreover, its ability to convert a wide variety of currently available fossil fuels has reduced the operating cost, thus, makes it dominant in fuel cells technologies competition. Still, SOFC systems are commonly operated at high temperature, in the range of 800 – 1000 °C. Lowering the operating temperature to intermediate level of 500-800 °C is considered as a strategic approach in overcoming the drawbacks related to durability and system cost of commonly applied high temperature SOFC. However, oxygen reduction in intermediate temperature SOFC (IT-SOFC) cathode becomes the limiting factor of overall cell performance. This makes development of cathode with high catalytic activity becomes a critical issue for the IT-SOFC. In this review, the types and properties of materials reportedly deemed suitable for cathode, with an emphasis on the requirements for operation at intermediate temperature, are compiled. Perovskite based materials (manganite cathode, cobaltite cathode, and ferrite cathode) are the focus and their performance in terms of electrical conductivity, oxygen diffusity, as well as thermal expansion coefficient are summarized.