BaZr0.8Y0.2O3-delta (BZY) layers with various thicknesses ( similar to 0.7, similar to 1.7, similar to 2.4 and similar to 3.6 mu m) are fabricated using the pulsed laser deposition (PLD) technique on anode-supported BaCe0.8Y0.2O3-delta (BCY) electrolyte films. Sm0.5Sr0.5CoO3-delta-SDC (SSC-SDC, 70:30 wt.%) cathode is applied onto the BZY/BCY bilayer electrolyte to form a single cell. The chemical stability of the BZY/BCY bilayer electrolytes improves with increasing BZY layer thickness. The BZY ( similar to 3.6 mu m)/BCY bilayer electrolyte shows an excellent chemical stability after treated in 100% CO2 atmosphere at 900 C. The maximum power densities of 447, 370, 276, 218 and 163 mW cm(-2) are measured with the BZY layer thicknesses of 0, 0.7, 1.7, 2.4 and 3.6 mu m at 700 degrees C, respectively. In general, the BZY/BCY bilayer electrolyte cell with an optimum BZY layer thickness can improve chemical stability without great influence on the electrochemical performance for intermediate temperature solid oxide fuel cells. (C) 2013 Elsevier B.V. All rights reserved.