Preparation of Ba1.2Sr0.8CoO4+δ K2NiF4-type structure oxide and cathodic behavioral of Ba1.2Sr0.8CoO4+δ-GDC composite cathode for intermediate temperature solid oxide fuel cells

The Ba1.2Sr0.8CoO4+delta (BSC1208) material with K2NiF4-type structure was synthesized via EDTA-citrate process and characterized by XRD. Composite materials Ba1.2Sr0.8CoO4+delta -Ce0.9Gd0.1O1.9 (GDC) (BSC1208-GDC) were prepared and characterized as cathode for intermediate temperature SOFC (IT-SOFC). XRD results show that no reaction occurred between Ba1.2Sr0.8CoO4+delta and CDC at 1000 degrees C. For BSC1208-30 wt% CDC electrode, SEM results suggest that better microstructure was obtained and the electrode formed good contact with the electrolyte after sintering at 1000 degrees C for 2 h. Compared with the pure BSC1208 material, BSC1208-GDC composite materials exhibit better electrochemical properties. Especially, the BSC1208-30 wt% CDC electrode possesses the best electrochemical activity for oxygen reduction. At 750 degrees C, the polarization resistance of the BSC1208-30wt% GDC electrode is about 0.17 Omega cm(2) on CDC electrolyte which is nearly two times lower than that of the pure BSC1208 electrode, and the lowest polarization overpotential is -0.103 V at a current density of 498 mA cm(-2). (C) 2008 Elsevier B.V. All rights reserved.