Composition and microstructure optimization and operation stability of barium deficient Ba1axCo0.7Fe0.2Nb0.1O3aI' perovskite oxide electrodes

• Published in: Electrochimica acta Vol. 103; pp. 23 - 31
• Main Authors: Wang, Fucun, Chen, Dengjie, Shao, Zongping
• Format: Journal Article
• Language: English
• Published: 01.07.2013
• Subjects: Carbon dioxide; Cathodes; Electrodes; Electrolytic cells; Microstructure; Optimization; Oxides; Stability
• ISSN: 0013-4686
• DOI: 10.1016/j.electacta.2013.04.054

Ba1axCo0.7Fe0.2Nb0.1O3aI' oxides (x = 0, 0.05 and 0.10) were optimized as potential cathodes on oxygen ionic conductor electrolyte for intermediate temperature solid oxide fuel cells (IT-SOFCs). The creation of additional oxygen vacancies in Ba0.9Co0.7Fe0.2Nb0.1O3aI' was confirmed. Low polarization resistances of 0.015, 0.029 and 0.089 ICO cm2 were achieved at 700, 650 and 600 degree C, respectively. By further optimizing the microstructure of the Ba0.9Co0.7Fe0.2Nb0.1O3aI' electrode by using polyvinyl butyral as a pore former and adjusting the sintering temperature, the maximum power density was improved from 682 to 955 mW cm-2 at 650 degree C. The operational stability of the Ba0.9Co0.7Fe0.2Nb0.1O3aI' electrode was also investigated. The CO2 in the surrounding air was detrimental to the oxygen reduction reaction; however, the performance of the cell was recovered after removing the CO2 in the air at 650 or 700 degree C. In addition, the Ba0.9Co0.7Fe0.2Nb0.1O3aI' electrode in symmetrical cells exhibited a stable performance at 650 degree C for 400 h and maintained a reliable performance after repeated thermal cycles from room temperature to 700 degree C. The results showed that Ba0.9Co0.7Fe0.2Nb0.1O3aI' was a promising cathode material for practical application in IT-SOFCs.