Electrochemical performance and chemical stability of proton‐conducting BaZr0.8−xCexY0.2O3−δ electrolytes

Abstract Protonic ceramic fuel cells (PCFCs) using BaZr 0.8− x Ce x Y 0.2 O 3− δ (BZCY) as electrolyte materials have attracted widespread attention because of their high performance at reduced temperature. However, there are few systematic studies on both the performance and stability of BZCY materials. In this paper, we report our work on the electrochemical performance and chemical stability of BaZr 0.8− x Ce x Y 0.2 O 3− δ ( x = 0, 0.1, 0.3, 0.5, and 0.7) series. The results show that electronic hole conductivity decreases with increasing Ce 4+ content, especially at high temperature. In addition, H 2 atmosphere reduces the conductive activation energy of BZCY. On the contrary, air atmosphere causes serious electronic leakage. These effects are also reflected in the operation of PCFCs, that is, the higher the Ce 4+ content, the higher the open‐circuit voltage and output power density. However, low Ce 4+ content may stabilize the materials in CO 2 atmosphere. At 700°C, an anode‐supported PCFC based on BaZr 0.1 Ce 0.7 Y 0.2 O 3− δ electrolyte, using humid H 2 fuel, gives a peak power density of 1.0 W cm −2 . At 600°C, BaZr 0.8 Y 0.2 O 3− δ and BaZr 0.7 Ce 0.1 Y 0.2 O 3− δ show a good stability in CO 2 ‐containing atmosphere.