The potential of a novel co-doped ceria material Sm0.075Nd0.075Ce0.85O2-delta as an electrolyte was investigated under fuel cell operating conditions. Conventional colloidal processing was used to deposit a dense layer of Sm0.075Nd0.075Ce0.85O2-delta (thickness 10 mu m) over a porous Ni-gadolinia doped ceria anode. The current-voltage performance of the cell was measured at intermediate temperatures with 90 cm(3) min(-1) of air and wet hydrogen flowing on cathode and anode sides, respectively. At 650 degrees C, the maximum power density of the cell reached an exceptionally high value of 1.43 WCm-2, with an area specific resistance of 0.105 Omega cm(2). Impedance measurements show that the power density decrease with decrease in temperature is mainly due to the increase in electrode resistance. The results confirm that Sm0.075Nd0.075Ce0.85O2-delta is a promising alternative electrolyte for intermediate temperature solid oxide fuel cells. (C) 2009 Elsevier B.V. All rights reserved.