BaZr0.8Y0.2O3-δ (BZY) layers with various thicknesses (∼0.7, ∼1.7, ∼2.4 and ∼3.6 μm) are fabricated using the pulsed laser deposition (PLD) technique on anode-supported BaCe0.8Y0.2O3-δ (BCY) electrolyte films. Sm0.5Sr0.5CoO3-δ-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(∼3.6 μm)/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 μm at 700°C, respectively. In gerenal, 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.