Strontium-substituted Ba(Ce, Zr) O3-δ oxides for proton conducting membranes

This paper is focused on Ba1-xSrx(Ce0.75Zr0.25)(0.9)Nd0.1O2.95 proton-conducting oxides, for which the effect of substitution of barium by strontium in a full range of compositions is studied. Crystal lattice symmetry, proton conductivity and stability in CO2 atmosphere are discussed. Substitution of barium by strontium reduces toxicity and does not deteriorate chemical stability, however, crystal lattice of the strontium-substituted perovskites is more distorted, causing reduction of proton conductivity more than one order of magnitude. Balance between opposite tendencies can be found at low Sr content, e. g., 25 at.%. Keywords: Proton-conducting oxides; perovskite; electrical conductivity; crystal structure; stability in CO2 atmosphere.