Study on Ce and Y co-doped BaFeO3-δ cubic perovskite as free-cobalt cathode for proton-conducting solid oxide fuel cells. (6th July 2021)

• Record Type: Journal Article
• Authors: Wei, Zhaoling; Wang, Jinpeng; Yu, Xinchao; Li, Zhongbiao; Zhao, Yujun; Chai, Jinling
• Is Part Of: International journal of hydrogen energy. Volume 46:Number 46(2021)
• Page Start: 23868
• Page End: 23878
• Publication Date: 2021-07-06
• Subjects: Proton-conducting solid oxide fuel cell -- Cathode -- Barium ferrite -- Cubic perovskite; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2021.04.188
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: The use of triple-conducting (electron, proton, oxide ion) cathodes is an effective strategy for significantly decreasing cathode polarization of proton-conducting SOFCs. In this study, a new triple-conducting BaFe0.8 Ce0.1 Y0.1 O3-δ (BFCY) perovskite cathode is prepared by Pechini sol-gel process and its properties are evaluated comprehensively. High-temperature XRD measurement demonstrates that the codoping of Ce and Y can stabilize the cubic perovskite of BFCY in investigated temperature range from room temperature to 900 °C. BFCY material exhibits a moderate average thermal expansion coefficient of 22.08 × 10 −6 K −1 smaller than cobalt-based cathode and good chemical compatibility with BaZr0.1 Ce0.7 Y0.2 O3-δ (BZCY) electrolyte after the calcining treatment at 1000 °C. XPS analysis indicates the existence of Ce 3+/4+ and Fe 3+/4+ ions and abundant oxygen vacancies in BFCY powder surface. Thermal gravimetric analysis reveals that a larger number of oxygen deficiencies -are generated at elevated temperatures, which favors the catalytic activity on oxygen reduction. The maximum value of BFCY electrical conductivity remains at 1.55 S cm −1 at 600 °C in humidified air. BCFY (BaCe0.8 Fe0.1 Y0.1 O3-δ ) material is introduced in order to construct BFCY-BCFY composite cathode with the good cathode/electrolyte interface adhesion. For the single cell with BFCY-BCFY composite cathode, the polarization resistance as low as 0.05 Ω cm 2 and peak power density as high as 750 mW cm −2 are reached at 700 °C, respectively, demonstrating the great potential of BFCY oxides as proton-conducting SOFC cathode. Highlights: BFCY shows stable cubic perovskite structure in investigated temperature range. A peak power density of 750 mW cm −2 is reached at 700 °C. BFCY-BCFY cathode shows a low area specific resistance of 0.05 Ω cm 2 at 700 °C.