Ni/Gd0.2Ce0.8O2-delta (Ni/GDC) anodes were infiltrated with various amounts of the proton conductor SrCe0.95Yb0.05O3-alpha (SCYb) with the goal of improving the performance of solid oxide fuel cells. First, the electrochemical characteristics of the Ni/GDC and Ni/GDC-SCYb anodes were evaluated in humidified hydrogen (1% H2O) fuel and in dry methane fuel at 1173 K, and then the durability of the anodes against carbon deposition was evaluated using an accelerated degradation test. Results revealed that the maximum power density of the Ni/GDC-SCYb anode was 50% higher than that of the Ni/GDC anode, namely 0.648 W/cm(2) in humidified H-2 and 0.438 W/cm(2) in dry methane. In conclusion, the performance of Ni/GDC anodes can be improved in either humidified hydrogen fuel or dry methane fuel by infiltration with SCYb. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3462983] All rights reserved.