Improved electrochemical oxidation kinetics of La0.5Ba0.5FeO3-δ anode for solid oxide fuel cells with fluorine doping

• Published in: Journal of power sources 2022-02, Vol.521, p.230932, Article 230932
• Main Authors: Hou, Nianjun, Gan, Juanjuan, Yan, Qisheng, Zhao, Yicheng, Li, Yongdan
• Format: Article
• Language: English
• Subjects: Anion doping; Anode; Hydrocarbon fuel; Lanthanum ferrite; Solid oxide fuel cell
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2021.230932

Sluggish anode kinetics and serious carbon deposition are two major obstacles to developing hydrocarbon fueled solid oxide fuel cells. A highly active and stable perovskite La0.5Ba0.5FeO3-δ anode material is studied in this work. The oxygen surface exchange and charge transfer steps are the rate-determining steps of the anode process, and the former is accelerated with fluorine doping on the anion sites due to the lowering of metal-oxygen bond energy. The oxygen surface exchange coefficients of La0.5Ba0.5FeO3-δ and La0.5Ba0.5FeO2.9-δF0.1 at 850 °C are 1.4 × 10−4 and 2.8 × 10−4 cm s−1, respectively. A single cell supported by a 300 μm-thick La0.8Sr0.2Ga0.8Mg0.2O3-δ electrolyte layer with La0.5Ba0.5FeO3-δ anode shows maximum power densities of 1446 and 691 mW cm−2 at 850 °C with wet hydrogen and methane fuels, respectively, which increase to 1860 and 809 mW cm−2 respectively when La0.5Ba0.5FeO2.9-δF0.1 is used as the anode. The cell exhibits a short-term durability of 40 h using wet methane as fuel without carbon deposition on the anode. •La0.5Ba0.5FeO3-δ perovskite is developed as an anode material of SOFCs.•The oxygen surface exchange on the anode is accelerated through F anion doping.•La0.5Ba0.5FeO2.9-δF0.1 anode shows high activity and stability with CH4 fuel.