Solid oxide fuel cells (SOFCs) with Nio-ScSZ and Ni0.9Mg0.1O-ScSZ-based anodes were operated by directly feeding a fuel mixture of CH4, CO2 and N-2 (CH4 to CO2 ratio of 3:2). Stable operation under constant current load (200 mA cm(-2)) was achieved with a NiO-ScSZ type anode during 200h operating hours at 900 degrees C. Less stable operation occurred with a Ni0.9Mg0.1O-ScSZ type anode. In the case of SCFC with Ni0.9Mg0.1O-SCSZ as the anode, the methane reforming activity was higher than that with NiO-ScSZ. This was explained by change in the microstructure promoting reforming reactions. However, the addition of MgO resulted in degradation of electrochemical performance due to increase in ohmic resistance of the anode material during operation. (C) 2008 Elsevier B.V. All rights reserved.