Conductivity dependence on oxygen partial pressure and oxide-ion transport numbers determination for La2Mo2O9

Transport number measurements and impedance spectroscopy in controlled temperature and atmosphere were used to investigate the electrical conduction properties of La2Mo2O9. The compound is a pure oxygen ion conductor in the temperature range of 400-800 degrees C with oxide ion transport numbers greater than 0.99. The effect of the oxygen partial pressure on the electrical conductivity of La2Mo2O9 was investigated from 1 to 10(-22) atm, showing that the material is stable and mainly an ionic conductor down 10(-17) atm at 800 degrees C. These results confirm the suitability of the recently discovered La2Mo2O9-based compounds as electrolytes in solid oxide fuel cell applications. (C) 2004 The Electrochemical Society.