In this chapter, we highlight some critical aspects of materials for use in solid oxide fuel cells. In relation to oxide ion conducting electrolytes, we address topics including clustering of defects in zirconias and the resultant limitations on ionic conductivity. We also discuss the ionic conduction window for various electrolyte systems. The positive and negative attributes of different anode materials are considered, highlighting the opportunities for alternative materials to be utilised in certain parts of the SOFC system. Some suitable system concepts are presented and a strategy to optimise performance and durability in the same electrode structures is presented.
