Performance Comparison of Perovskite Composite Cathodes with BaZr _0.1 Ce _0.7 Y _0.1 Yb _0.1 O _{3– <i>δ</i>} in Anode-Supported Protonic Ceramic Fuel Cells

Abstract

The present work investigates electrochemical performance of anode-supported protonic ceramic fuel cells (PCFCs) with composite cathodes consisting of an electronic conductive perovskite oxide and a protonic conductive BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3– δ (BZCYYb). Although PCFCs are expected as a future high-efficiency device, further higher performance and reliability are essential. Thus, to enhance cathode performance, three conventional perovskite oxides, La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3– δ (LSCF), La 0.6 Sr 0.4 CoO 3– δ (LSC), and La 0.6 Ba 0.4 CoO 3– δ (LBC), that are commonly used in traditional solid oxide fuel cells, are evaluated here as the electronic conductive phase in cathodes containing BZCYYb. Results show that all three of these electronic conductive perovskite oxides are compatible with BZCYYb and stably function as a cathode in PCFC operation. Comparison among these three composite cathodes reveals that the PCFC with the LBC-BZCYYb cathode demonstrate the highest performance, e.g., maximum power densities of 0.57 W cm −2 at 600 °C and 1.0 W cm −2 at 700 °C. In addition, impedance spectra and fitting analysis reveal that the low electrode polarization resistance in the lower frequency range of the LBC-BZCYYb cathode contributes to the PCFC performance. In summary, composites of perovskite oxides, particularly LBC-BZCYYb, are suitable as cathode material to achieve high performance as well as stable operation in PCFCs.