Substantial appearance of origin of conductivity decrease in Y-doped BaZrO[3] due to Ba-deficiency

Abstract

Y-doped BaZrO[3] (BZY) is getting attention due to its high proton conductivity. But the proton conductivity decreased when Ba-deficiency was introduced. And we recently found that the system with an atomic ratio of Ba : Zr : Y of 0.9 : 0.8 : 0.2 contained two perovskite phases (Ba[0.74]Zr[0.55]Y[0.45]O[3−δ] and Ba[0.90]Zr[0.88]Y[0.12]O[3−δ]). In this work, by scanning transmission electron microscopy (STEM), accumulation of stacking faults with higher content of Zr, Y or vacancies than Ba was observed in the Ba[0.74]Zr[0.55]Y[0.45]O[3−δ] phase. We discuss the influence of the phase on the conductivity based on the results of water content and conductivity measurements, and therefore assume that the proton conduction in the Ba[0.74]Zr[0.55]Y[0.45]O[3−δ] phase might be very small.