Conductivity and stability of SrVO3 and mixed perovskites at low oxygen partial pressures

The electrical conductivity and chemical stability of ABO3 (where the A-site contains La or Sr, and the B-site contains Ni, V, Ti, Nb, Mo or W and combinations thereof) have been studied in air and reducing atmospheres. Neither the rare-earth vanadates, such as LaVO3, nor the alkaline-earth vanadates, with the exception of SrVO3, are good electronic conductors. SrVO3 shows excellent electronic conductivity of 1000 S/cm at 800°C and an oxygen partial pressure of 10−20 atm, but is unstable under more oxidizing conditions. However, strontium-doped lanthanum vanadates are stable over a range of oxygen partial pressures of 10−14–10−20 atm. La0.7Sr0.3VO3−δ has a conductivity of 50 S/cm at 800°C and PO2=10−20 atm. However, none of the compounds studied have both adequate high-temperature electrical conductivity in reducing atmospheres and stability to cycling between oxidizing/reducing conditions, to serve as anodes in solid oxide fuel cells.