Electrolytes for the high temperature fuel cell; experimental and theoretical studies of the perovskite LaAlO3

We present electrical conductivity measurements on a range of samples, based on the perovskite oxide LaAlO3, in the temperature span 600 – 1000 °C and under controlled partial pressures of oxygen The conductivity is described for a series of compositions made oxygen deficient by replacement of either the La3+ or Al3+ cations by the divalent cations Ca2+, Mg2+, Sr2+. We also present transport number measurements which indicate that charge transport in these materials is purely ionic for reducing atmospheres (pO2 ∼ 10−14 atm.). The Arrhenius energies calculated from the ionic conductivities fall in the range 1.0 to 3 eV.