Proton conduction in (La0.9Sr0.1)MIIIO3−δ (MIII=Sc, In, and Lu) perovskites

The electrical conductivity of A3+B3+O3-type perovskites, (La0.9Sr0.1)MIIIO3−δ (MIII=Sc, In, and Lu) (LSM), was investigated under controlled atmospheres between 573 and 1273 K. At P(O2)>10−5 atm, all the compounds showed the predominant proton conduction below 873 K under wet conditions; at P(O2)<10−10 atm, the Sc and In compounds below 873 K and the Lu-one at all temperatures under hydrogen-containing conditions. The Sc compound showed the highest proton conductivity of ca. 4×10−3 S· cm−1 at 873 K in the presence of water vapor or hydrogen. The proton conductivity of LSM decreased with increasing the size of B-site (MIII) cation.