Characterization of Ba sub(1.0)Sr sub(1.0)FeO sub(4+ delta ) cathode on La sub(0.9)Sr sub(0.1)Ga sub(0.8)Mg sub(0.2)O sub(3- delta ) electrolyte for intermediate temperature solid oxide fuel cells

• Published in: Journal of power sources 2011-08, Vol.196 (15), p.6238-6241
• Main Authors: Yin, Yanping, Liu, Bangwu, Qi, Junjie, Gu, Yousong, Liao, Qingliang, Qin, Zi, Li, Zhanqiang, Wang, Qinyu, Zhang, Yue
• Format: Article
• Language: English
• Subjects: Cathodes; Electric potential; Electrolytes; Ethylene; Field emission; Resistivity; Solid oxide fuel cells
• ISSN: 0378-7753
• DOI: 10.1016/j.jpowsour.2011.03.019

Ba sub(1.0)Sr sub(1.0)FeO sub(4+ delta ) (BSFO) with A sub(2)BO sub(4) structure as a cathode material for intermediate temperature solid oxide fuel cells (IT-SOFCs) is synthesized through an ethylene diamine tetraacetic acid (EDTA)-citrate process, and characterized by X-ray diffraction. Field emission scanning electron microscopy shows that BSFO cathode is well attached to the La sub(0.9)Sr sub(0.1)Ga sub(0.8)Mg sub(0.2)O sub(3- delta ) (LSGM) electrolyte. The electrical conductivity measured by DC four-probe method increases as the temperature increases. A linear relationship between ln([sigma]T) and 1000/T indicates that the conducting behavior obeys the small polaron conductivity mechanism. Electrochemical performance of BSFO cathode on LSGM electrolyte is investigated in the temperature range from 500 [deg]C to 800 [deg]C. The results indicate that oxygen adsorption/dissociation process dominates cathodic reaction. Furthermore, the polarization resistance of BSFO cathode decreases with increasing temperature, and declines to 1.42 [Omega] cm[super]2 at 800 [deg]C. These results show that BSFO can be a promising cathode material used on LSGM electrolyte for IT-SOFCs. The figure shows the impedance spectra of BSFO cathode on LSGM electrolyte and the corresponding equivalent circuits without bias voltage in the air from 500 [deg]C to 800 [deg]C: (a) 500-550 [deg]C; (b) 600-800 [deg]C.[inline image]