From theory to experiment: BaFe0.125Co0.125Zr0.75O3-δ, a highly promising cathode for intermediate temperature SOFCs

In a recent theoretical study [Jacobs et al., Adv. Energy Mater., 2018, 8, 1702708], BaFe0.125Co0.125Zr0.75O3-delta was predicted to be a stable phase with outstanding performance as an auspicious cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). It is shown here that the theoretical predictions are valid. The material can be synthesized by the citrate method as a single cubic Pm3m phase with a significant amount of oxygen vacancies, randomly distributed in the anionic sublattice facilitating oxygen vacancy conduction. A thermal expansion coefficient of 8.1 x 10(-6) K-1 suggests acceptable compatibility with common electrolytes. Electrochemical impedance spectroscopy of symmetrical cells gives an area-specific resistance of 0.33 Omega cm(2) at 700 degrees C and 0.13 Omega cm(2) at 800 degrees C. These values are reduced to 0.13 Omega cm(2) at 700 degrees C and 0.05 Omega cm(2) at 800 degrees C when the material is mixed with 30 wt% Ce0.9Gd0.1O2-delta.