Mo-doped BaCe0·9Y0·1O3-δ proton-conducting electrolyte at intermediate temperature SOFCs. Part I: Microstructure and electrochemical properties.

Researchers' interest in proton-conducting reversible solid oxide cells (RSOCs) is growing due to their distinct benefits. In the present work, single-phase BaCe 0.9–x Mo x Y 0.1 O 3–δ (x = 0, 0.025, 0.05, 0.1, 0.2) electrolyte is prepared via sol-gel method and sintered at 1400 °C for 10 h. Optimal density, structure, composition, electrochemical performance, and thermal stability are confirmed via SEM, XRD, EDS, XPS, FTIR, EIS, and TGA/DSC. The conductivity of the grain interior and boundaries between 127 and 727 °C is reported for the first time in SOFC studies. The BaCe 0·875 Mo 0·025 Y 0·1 O 3–δ sample shows a grain interior conductivity of 1.3 × 10−3 S cm −1 at 707 °C with grain interior activation energy of 0.75 eV (127–727 °C), and a grain boundary activation energy of 0.85 eV (380–727 °C), 0.43 eV (167–357 °C) in air atmosphere, respectively. BaCe 0.875 Mo 0.025 Y 0.1 O 3–δ showed extreme stability for 300 h, and thus can be considered suitable for an efficient protonic conductor at intermediate temperatures. [Display omitted] • Mo-doped BaCe 0.9–x Mo x Y 0.1 O 3 (x = 0, 0.025, 0.05, 0.1, 0.2) were explored as IT-SOFCs. • BCY-0.025 Mo showed bulk activation energy of 0.63 eV (127–727 °C). • BCY-0.025 Mo showed grain boundary activation energy of 0.82 eV (167–357 °C). • TG/DSC results showed no observable mass loss until 700 °C for x = 0.025 and 0.05. • Long-term stability (300 h) was achieved using BaCe 0.875 Mo 0.025 Y 0.1 O 3. [ABSTRACT FROM AUTHOR]