A novel high performance composite anode with in situ growth of Fe-Ni alloy nanoparticles for intermediate solid oxide fuel cells

Highlights: • A composite anode with endogenous Fe-Ni alloy nanoparticles has been prepared. • The redox reversibility of the anode has been confirmed by XRD. • The E_a of H₂ oxidation at the anode is much smaller than that at Ni-YSZ anode. • A ScSZ supported cell achieves MPD of 0.71 Wcm⁻² and R_p of 0.16 Ω cm² at 800 °C. • The single cell shows stable output during 105 h testing at 800 °C 0.7 V in wet H₂^. - Abstract: A redox reversible composite anode with Fe-Ni alloy nanoparticles in situ growth on SrLaFeO₄-type and LaFeO₃-type oxide substrates has been prepared for intermediate temperature solid oxide fuel cell (IT-SOFC) by reducing perovskite precursor La_0.4Sr_0.6Fe_0.75Ni_0.1Nb_0.15O_3-δ (LSFNNb) in wet H₂ at 900 °C for 1 h. The anode has shown an excellent electrochemical catalytic activity for oxidation of hydrogen with much smaller E_a (25.1 ∼ 68.9 kJ mol⁻¹) than the value (>160 kJ mol⁻¹) at Ni-YSZ anode. A scandium stabilized zirconia (ScSZ) electrolyte supported SOFC with the anode achieves maximum power densities of 0.71, 0.52, 0.35, and 0.21 W cm⁻² at 800, 750, 700 and 650 °C, respectively in wet H₂ (3% H₂O), and the corresponding R_p of 0.16, 0.21, 0.35, and 0.60 Ω cm² under OCV. Moreover, the single cell shows stable power output during ∼105 h operation at 800 °C under 0.7 V in wet H₂ after a initial degradation, indicating that R-LSFNNb is an excellent candidate as anode of IT-SOFC.