Traditional solid oxide fuel cells (SOFCs) with Ni cermet anode are not stable operating in CH4 due to carbon deposition. Here we report excellent long-term stability of the cell with Ni/SDC anode is achieved in 3% H2O humidified CH4 in a temperature range of 700-800 degrees C by addition of 1wt%Sn to the porous anode. The addition of a small amount of Sn does not compromise the electrochemical performance of the cell in humidified H-2. For the 1%Sn-Ni/SDC anode, the peak power density of the cell reaches 0.28 Wcm(-2) in 3% H2O humidified CH4 and the current density decreases only by 30% after the cell is operated under a constant voltage of 0.8 V in humidified CH4 for 230 h at 700 degrees C. The Ni and Sn mappings of the tested cell indicate that Sn is enriched on the anode surface and Sn-Ni intermetallics form. It is found that a critical process is essential to oxidize the impregnated SnCl2 into SnO2 at a temperature higher than 800 degrees C, hence metallic Sn can'be obtained and consequently it further forms highly catalytic activity Sn-Ni intermetallics in H-2. These results demonstrate that the addition of 1wt%Sn can significantly enhance the coking tolerance of the Ni/SDC anode. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.