Abstract
Cathodes are one of the key components of protonic ceramic fuel cells (PCFCs) requiring further
development to enhance the performance of PCFCs. This encompasses the optimization of material
compositions and microstructures, as well as a further understanding of the electrode processes. Here,
a compositional optimization of a La0.5Ba0.5CoO3−δ—BaZrO3-based nano-composite cathode
prepared by exsolution of a single-phase material was performed by substituting 5 and 10 mol% Y at
the B-site in the BaZrO3 phase. Electrodes with different microstructures were prepared by two
different deposition methods, spray coating and screen printing, and by varying the firing temperature
from 600°Cto 1100 °C. Further, composite electrodes were prepared by directly coating and firing the
single-phase materials on the dense electrolyte to prepare symmetric cells. A good adhesion of the
cathode to the electrolyte was observed in all cases. In general, a more homogeneous microstructure
was observed for the cathodes prepared by screen printing. The single step method encompassing
exsolution of the single phase and firing of the symmetric cells yielded significant improvement in the
cathode performance compared to the other routes. The best electrochemical performance was
observed for La0.5Ba0.5CoO3−δ—BaZr0.9Y0.1O2.95 cathode with an area specific resistance of
4.02 Ω·cm2 at 400 °Cand 0.21 Ω·cm2 at 600 °Cin 3%moist synthetic air. These results are among
the best reported for cathodes of PCFCs as will be discussed.
development to enhance the performance of PCFCs. This encompasses the optimization of material
compositions and microstructures, as well as a further understanding of the electrode processes. Here,
a compositional optimization of a La0.5Ba0.5CoO3−δ—BaZrO3-based nano-composite cathode
prepared by exsolution of a single-phase material was performed by substituting 5 and 10 mol% Y at
the B-site in the BaZrO3 phase. Electrodes with different microstructures were prepared by two
different deposition methods, spray coating and screen printing, and by varying the firing temperature
from 600°Cto 1100 °C. Further, composite electrodes were prepared by directly coating and firing the
single-phase materials on the dense electrolyte to prepare symmetric cells. A good adhesion of the
cathode to the electrolyte was observed in all cases. In general, a more homogeneous microstructure
was observed for the cathodes prepared by screen printing. The single step method encompassing
exsolution of the single phase and firing of the symmetric cells yielded significant improvement in the
cathode performance compared to the other routes. The best electrochemical performance was
observed for La0.5Ba0.5CoO3−δ—BaZr0.9Y0.1O2.95 cathode with an area specific resistance of
4.02 Ω·cm2 at 400 °Cand 0.21 Ω·cm2 at 600 °Cin 3%moist synthetic air. These results are among
the best reported for cathodes of PCFCs as will be discussed.
