Defect Chemistry and Electrical Conductivity of Sm-Doped La_1–<i>x</i>Sr_<i>x</i>CoO_3−δ for Solid Oxide Fuel Cells

Abstract

We have calculated the electrical conductivity of the solid oxide fuel cell (SOFC) cathode contact material La 1– x Sr x CoO 3−δ at 900 K. Experimental trends in conductivity against x, and against δ for fixed x, are correctly reproduced for x ≲ 0.8. Furthermore, we have studied the chemistry of neutral and charged intrinsic and extrinsic defects (dopants) in La 0.5 Sr 0.5 CoO 3 and have calculated the conductivity of the doped systems. In particular, we find that doping with Sm on the La site should enhance the conductivity, a prediction that is subsequently confirmed by electrical conductivity measurements.