Anisotropic catalytic activity of the orientation controlled Nd2NiO4 + δ/YSZ hetero-epitaxial system for SOFC cathode

Electrode–electrolyte hetero-epitaxial systems for solid oxide fuel cells (SOFCs) with two different configuration of Nd2NiO4 + δ(110)//YSZ(100) and Nd2NiO4 + δ(100)//YSZ(110) were successfully fabricated by pulsed laser deposition. Thin films of Nd2NiO4 + δ approximately 20 nm thick were grown on a commercial single crystal of YSZ. The preferred two-dimensional diffusion paths of the oxide ions were perpendicular to the substrate for both configurations and showed oxygen reduction capability different from each other. This opens up new research direction focusing on the details of anisotropic catalytic activity of SOFC cathode depending on the crystalline surface.