Instability and growth of nanoscale Ce_0.8Gd_0.2O_1.9/NiO infiltrate in Sr_0.94Ti_0.9Nb_0.1O₃-Zr_0.84Y_0.16O_1.92 anodes for solid oxide fuel cells

Microstructural evolution of Ce0.8Gd0.2O 1.9/NiO (CGO/NiO) co-infiltrated nanoparticles in Sr 0.94Ti0.9Nb0.1O3-Zr 0.84Y0.16O1.92 (STN94-YSZ) anodes for solid oxide fuel cells (SOFCs) is investigated during electrochemical testing in a symmetric cell setup. The CGO/NiO infiltrated symmetric cells were subjected to varying atmospheres of H2O/H2 between 650 and 850 C and characterized by electrochemical impedance spectroscopy. Analytical high resolution transmission electron microscopy showed that the CGO/NiO infiltrate was found to coalesce and grow from an indistinguishable CGO/NiO fluorite structure of an average diameter of 5 nm to individual well-connected, but phase-separated, CGO and Ni particles of 50 nm in average. This study confirms that instability and growth of CGO/NiO infiltrates in STN-based SOFC electrodes affect the morphology and can potentially be linked to reported losses in electrochemical performance. © 2014 Elsevier B.V. All rights reserved.