B-site rock salt-type ordered double perovskites Sr2 - xBaxMMoO6 - delta (M = Co, Ni; x = 0, 0.5, 1, 1.5 and 2) were evaluated as novel anode materials for SOFC fuel cells. Phase composition, crystal structure, oxygen content transport properties, chemical stability in relation to ceria electrolyte and chemical stability of Sr2-xBaxMMoO6 - delta under reducing atmospheres were studied. It was found that Sr2CoMoO6 - delta and Sr2NiMoO6 - delta possess I4/m symmetry at room temperature, while all other anode materials are cubic with Fm-3m space group. SrBaMMoO6 - delta oxides exhibit thermal expansion coefficient in the range 11.7-14.3 . 10(-6) K-1, which is comparable to that of Ce0.8Gd0.2O1.9 electrolyte. All Sr2 -xBaxMMoO6 - delta oxides show low electrical conductivity in air (ca. 10(-3)-10(-1) S cm(-1) at 800 degrees C). Stability studies performed in reducing conditions indicate that these materials decompose at temperatures lower than 800 degrees C in 5 vol.% H-2 in Ar and lower than 700 degrees C in pure H-2, which suggests that previous literature data showing enhanced conductivity in reducing conditions may not be entirely correct. Interestingly, despite total decomposition of the anode material, relatively high performance of constructed SOFCs was recorded. Moreover, addition of Ni to the anode caused an increase of power density up to 0.16W cm(-2) at 850 degrees C. (C) 2014 Elsevier B.V. All rights reserved.