Efficient symmetrical electrodes of PrBaFe2-xCoxO5+δ (x=0, 0.2,0.4) for solid oxide fuel cells and solid oxide electrolysis cells

Abstract

Symmetrical solid oxide fuel cells (SSOFCs) can simplify the fabrication process, improve the coking and sulfur poisoning resistance by transforming the anode and cathode, switch flexibly between solid oxide fuel cells (SOFCs) model and solid oxide fuel cells (SOECs) model, and thus have attracted great attention in recent years. In this work, the layered perovskites PrBaFe2-xCoxO5+δ (x = 0, 0.2) are studied as symmetrical electrodes for SOFCs and SOECs. PrBaFe1.8Co0.2O5+δ (PBFC02) has better catalytic performance for oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR) than PrBaFe2O5+δ (PBF). In H2, PBFC02 sample would decompose to PBF, Ba6Pr2Fe4O15 and Co3Fe7. The X-ray diffractometer (XRD) and Energy dispersive spectrometer (EDS) results demonstrate that PBFC02 sample has good chemical compatibility with La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM) electrolyte. At 800 °C, the polarization resistance values of PBFC02 symmetrical electrodes are 0.026 and 0.319 Ω cm2 in air and H2, respectively. The output performances of the electrolyte-supported single cell with the PBFC02 symmetrical electrodes are 735, 626 and 268 mW cm–2 at 850 °C under H2, liquefied petroleum gas, and C2H5OH fuel, respectively. Moreover, the symmetrical cell with the PBFC02 electrodes shows good electrochemical performance and stability for the co-electrolysis of H2O/CO2 at intermediate temperatures for SOECs.