Chemical Compatibility and Electrochemical Performance of Ba₇Ta_3.7Mo_1.3O_20.15 Electrolytes for Solid Oxide Fuel Cells

Hexagonal perovskite-related oxides Ba7Ta3.7Mo1.3O20.15 (BTM) have recently been reported as promising electrolyte materials for intermediate-temperature solid oxide fuel cells (ITSOFCs). In this work, sintering properties, thermal expansion coefficient, and chemical stability of BTM were studied. In particular, the chemical compatibilities of (La0.75Sr0.25)(0.95)MnO3 +/-delta (LSM), La0.6Sr0.4CoO3 (LSC), La0.6Sr0.4Co0.2Fe0.8O3+delta (LSCF), PrBaMn2O5+delta (PBM), Sr2Fe1.5Mo0.5O6- delta (SFM), BaCo0.4Fe0.4Zr0.1Y0.1O3-delta (BCFZY), and NiO electrode materials with the BTM electrolyte were evaluated. The results show that BTM is highly reactive with these electrodes, in particular, BTM tends to react with Ni, Co, Fe, Mn, Pr, Sr, and La elements in the electrodes to form resistive phases, thus deteriorating the electrochemical properties, which has not been reported before.