Preparation of Ba_(1.2)Sr_(0.8)CoO_(4+delta)K_2NiF_4-type structure oxide and cathodic behavioral of Ba_(1.2)Sr_(0.8)CoO_(4+delta)-GDC composite cathode for intermediate temperature solid oxide fuel cells

摘要

The Ba_(1.2)Sr_(0.8)CoO_(4+delta) (BSC1208) material with K_2NiF_4-type structure was synthesized via EDTA-citrate process and characterized by XRD. Composite materials Ba_(1.2)Sr_(0.8)CoO_(4+delta)-Ce_(0.9)Gd_(0.1)O_(1.9) (GDC) (BSC1208-GDC) were prepared and characterized as cathode for intermediate temperature SOFC (IT-SOFC). XRD results show that no reaction occurred between Ba_(1.2)Sr_(0.8)CoO_(4+delta) and GDC at 1000 deg C. For BSC1208-30 wt percent GDC electrode, SEM results suggest that better microstructure was obtained and the electrode formed good contact with the electrolyte after sintering at 1000 deg C for 2h. Compared with the pure BSC1208 material, BSC1208-GDC composite materials exhibit better electrochemical properties. Especially, the BSC1208-30 wt percent GDC electrode possesses the best electrochemical activity for oxygen reduction. At 750 deg C, the polarization resistance of the BSC1208-30 wt percent GDC electrode is about 0.17 OMEGA cm~2 on GDC 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).