BaCe0.7Nb0.1Gd0.2O3-delta (BCNG) and BaCe0.8Gd0.2O3-delta (BCG) were synthesized by solid-state reaction method. The samples obtained were exposed in 3% CO2 + 3% H2O + 94% N-2 at 700 degrees C for 20 h in order to evaluate their chemical stability. It was found that BCNG exhibited adequate chemical stability while BCG decomposed and impurities were observed in the final products. Additionally. the BCNG demonstrated similar behavior as BCG in high-temperature thermal stability and in TEC and displayed a conductivity of 0.007 S cm(-1) at 700 degrees C in humid hydrogen which was slightly lower than BCG (0.009 S cm(-1)) at the same conditions. Fuel cells with BCNG as electrolyte were successfully fabricated and the thickness of BCNG layer can be easily adjusted as lower as 10 mu m by a simple all-solid-state process. The fuel cells exhibited OCV as high as 1.0 V at 700 degrees C with maximum Output power 340 mW cm(-2) and interfacial resistance as low as 0.51 Omega cm(2). (C) 2008 Elsevier B.V. All rights reserved.