Ionic conduction behaviors in Al-containing oxides, Lan-xSr1+xAlnO3n+1-α (n = 1 and 2), and in lanthanum niobate-based oxides, La3-xSrxNbO7-α, were investigated by using electrochemical methods at elevated temperatures. In La1-xSr1+xAlO4-α, single-phase was confirmed at x = 0 to 0.10. The highest conductivity in this solution appeared when x = 0.10 (2.4 x 10-4S/cm at 1000C in H2). The electromotive forces of gas concentration cells, and a H/D isotope effect upon the conductivity, suggested a definite contribution of protons to conduction. In H, pure ionic conduction was suggested to occur in La2SrAl2O7. Protonic conduction was confirmed in La3-xSrxNbO7-α. The electromotive forces for a water-vapor concentration cell in air suggested the occurrence of protonic conduction under high O partial pressure conditions.

Protonic Conduction in Lanthanum Strontium Aluminate and Lanthanum Niobate-Based Oxides at Elevated Temperatures. T.Shimura, Y.Tokiwa, H.Iwahara: Solid State Ionics, 2002, 154-155, 653-8