Multifunctional perovskite oxide Sr 2 Ti 1- x Ni x FeO 6-δ ( x=0.1, 0.2, 0.3) as symmetrical electrode for solid oxide cells

Symmetrical solid oxide fuel cells (SSOFCs) use the same materials as electrode, thereby reducing fabrication processes, simplifying interface problem and improving tolerance to coking and sulfur. In this paper, the multifunctional Sr2Ti0.8Ni0.2FeO6-delta (STN02F) oxide is successfully synthesized and evaluated to be as symmetrical electrodes for SOFCs. The Ni-Fe alloy nanoparticles can be exsolved from STN02F sample in high temperature reducing atmosphere. The impedance stability test demonstrates that the polarization resistance (Rp) of STN02F exhibited no obvious change in both air and H2. The fuel cells obtain the maximum power densities of 710 mW cm-2 in H2, 581 mW cm-2 in CH3OH, 527 mW cm-2 in C3H8 and 213 mW cm-2 in direct C at 800 degrees C. The fuel cell exhibited no output performance degradation during the 200 h test in H2. The current densities of 0.84 A cm-2 at 1.3 V in 50%H2O/50%H2 and 0.77 A cm-2 at 1.5 V in CO2 were obtained for electrolysis cell at 800 degrees C. The efficient and stable symmetrical electrode STN02F is a promising candidate material for SOCs.