Eight proton conducting oxygen-deficient perovskites BaIn 1 - x - yTixZryO 2.5 + (x + y)/2 - n(OH)2n with 0.2 ≤ x + y ≤ 0.5; 0 ≤ n ≤ 0.4 compounds were prepared by solid state reaction at 1350 C in air and studied by TGA, thermodiffraction, SEM and EIS. At low temperature, below 180 C, all compounds react with water vapor to incorporate protons. Hydration is associated with highly negative thermodynamic parameters. All the compounds present a disordered cubic symmetry except for the hydrated phases with the highest In content (x + y = 0.2) which present a cubic to tetragonal transformation below 250 C. Phases are chemically stable towards moisture and 3% CO2 atmosphere in temperature and present thermal expansion properties compatible with standard fuel cell materials. At high temperature the conductivity is mainly anionic (σO2- ≈ 0.01 S cm - 1 at 700 C) and below 600 C proton conductivity is observed. The best level of H+ conductivity was found for BaIn0.8Ti 0.05Zr0.15O2.6 (at 400 C, σH + = 2 × 10- 3 S cm- 1). For this family of compounds, it is shown that the proton conductivity level at 400 C is correlated to the basicity and that good protonic conductors at low temperature are also good anionic conductors at high temperature. © 2014 Elsevier B.V.
Mendeley saves you time finding and organizing research
Choose a citation style from the tabs below