Synthesis and characterization of Ba0.5Sr0.5Co0.8Fe0.1Ni0.1O3-δ cathode for intermediate-temperature solid oxide fuel cells

Abstract

Perovskite Ba0.5Sr0.5Co0.8Fe0.1Ni0.1O3-δ (BSCFNi) oxide is synthesized and characterized as a cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The X-ray diffraction (XRD) spectra show that BSCFNi is chemical compatible with La0.9Sr0.1Ga0.83Mg0.17O2.865(LSGM) electrolyte below 950 °C, but weak reaction is observed between BSCFNi cathode and Sm0.2Ce0.8O1.9 (SDC) electrolyte after calcined at 950 °C for 10 h. The XPS results indicate that transition metal cations in BSCFNi sample exist two different valence states, i.e., Co4+/3+, Fe4+/3+ and Ni3+/2+. The average thermal expansion coefficient (TEC) of BSCFNi is 18.7 × 10−6 K−1 between 200 °C and 850 °C in air. The maximum electrical conductivity reaches 35.3 Scm−1 at 425 °C in air. The polarization resistance of BSCFNi cathode on LSGM and SDC electrolytes are 0.033 and 0.066 Ωcm2 at 800 °C, respectively. The maximum power density of LSGM electrolyte-supported single cell with BSCFNi cathode reaches 690 mWcm−2 at 800 °C. These primarily results indicate that BSCFNi is a candidate cathode material for IT-SOFCs.