Enhancing oxygen reduction reaction of YSZ/La2NiO4+δ using an ultrathin La2NiO4+δ interfacial layer

Highlights: • The X-ray diffraction analysis of La₂NiO_4+δ confirms a pure and well-crystallized K₂NiO₄ structure. • The porous electrode sintered at 1200 °C/20 min degrades faster than the sintered at 1000 °C/2 h. • SEM micrographs confirm the presence of dense La₂NiO_4+δ ultrathin layer at the interface electrolyte/cathode. • The ultrathin La₂NiO_4+δ layer deposited by sputtering presents the best performance. In this work, La₂NiO_4+δ is used as cathode material for Intermediate temperature solid oxide fuel cells (IT-SOFC). Scanning electron microscopy, X-ray diffraction, and electrochemical impedance spectroscopy are used to investigate the effect of the presence of an ultrathin La₂NiO4_+δ layer (80 nm) deposited by dip-coating or sputtering at the interface YSZ/La₂NiO_4+δ. The thick porous cathode layer of La₂NiO_4+δ is deposited by screen-printing, and sintered at 1000 °C for 2 h or 1200 °C for 20 min in order to study the effect of sintering temperature on the electrochemical properties. The results show that the electrochemical performances of the cathode are influenced by the deposition technique. The best electrochemical properties are obtained with the use of the nano film interface layer deposited by sputtering. The introduction of ultrathin interface with nano grained between the cathode and electrolyte is a promising technique to reduce polarization resistance associated with oxygen reduction reaction (ORR) on the cathode.