Sr2Fe4/3Mo2/3O6 has been synthesized by a combustion method in air. It shows a single cubic perovskite structure after being reduced in wet H-2 at 800 degrees C and demonstrates a metallic conducting behavior in reducing atmospheres at mediate temperatures. Its conductivity value at 800 C in wet H2 (3% H2O) is about 16S cm(-1). This material exhibits remarkable electrochemical activity and stability in H-2. Without a ceria interlayer, maximum power density (P-max) of 547 mW cm(-2) is achieved at 800 degrees C with wet H-2 (3% H2O) as fuel and ambient air as oxidant in the single cell with the configuration of Sr2Fe4/3M2/3O6 vertical bar La0.8Sr0.2Ga0.83Mg0.17O3 (LSGM)vertical bar La0.6Sr0.4Co0.2Fe0.8O3 (LSCF). The P-max even increases to 595 mW cm(-2) when the cell is operated at a constant current load at 800 degrees C for additional 15 h. This anode material also shows carbon resistance and sulfur tolerance. The P-max is about 130 mWcm(-2) in wet CH4 (3% H2O) and 472 mW cm(-2) in H-2 With 100ppm H2S. The cell performance can be effectively recovered after changing the fuel gas back to H-2. (C) 2010 Elsevier B.V. All rights reserved.