The high temperature proton conductor BaZr0.4Ce0.4In0.2O3-α

• Published in: Journal of power sources Vol. 131; no. 1-2; pp. 289 - 292
• Main Authors: SHIMADA, T, WEN, C, TANIGUCHI, N, OTOMO, J, TAKAHASHI, H
• Format: Conference Proceeding Journal Article
• Language: English
• Published: Lausanne Elsevier Sequoia 01.01.2004
• Subjects: Applied sciences; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Chemical stability; Durability; Stabilized zirconia; Zr-substituted BaCeO3; High temperature; Cerium oxide; Solid oxide fuel cell; Open circuit voltage; Perovskite; Electrochemical properties; Barium oxide; Proton conductivity; Ionic transport number
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2003.11.087

The oxygen ion conductor yttria-stabilised zirconia (YSZ), which is usually used as the electrolyte in SOFCs, operates at temperatures of about 1000 C. The recent trend in SOFC development is to reduce the operating temperature. Proton conducting cerates may allow for intermediate temperature operation. Rare-earth-doped BaCeO3 electrolytes with the perovskite structure have good protonic conductivities at moderate temperatures but rather poor chemical stability and moisture resistance. Barium zirconate, in contrast, is a rather stable material but exhibits low protonic conductivity. A practical protonic conductor of BaZr0.4Ce0.4In0.2O3 (BZCI) that has relatively high moisture resistance and good protonic conductivity was considered. However, little is known about its stability and electrochemical properties in reducing hydrogen. The electrochemical properties of BZCI as SOFC electrolytes were investigated in concentration cell and fuel cell operations. Concentration cell measurements showed that BZCI has good proton conductivities in hydrogen-rich atmospheres and behaves as a protonic and oxide ionic conductor in oxygen-rich atmospheres, with some extent of electronic conductivity, which lowers its ionic transport number. Open circuit voltage (OCV) measurements in fuel cell operations showed that the OCV value of a Pt/BZCI/Pt cell is about 870 mV at 800 C and 1020 mV at 600 C. 10 refs.