In situ redox cycle of a nickel-YSZ fuel cell anode in an environmental transmission electron microscope
Environmental transmission electron microscopy is used in combination with density functional theory calculations to study the redox stability of a nickel/yttria-stabilized zirconia solid oxide fuel cell anode. The results reveal that the transfer of oxygen from NiO to yttria-stabilized zirconia triggers the reduction reaction. During Ni reoxidation, the creation of a porous structure, due to mass transport, accounts for the redox instability of the Ni-based anode. Both the expansion of NiO during a redox cycle and the presence of stress in the yttria-stabilized zirconia grains are observed directly. Besides providing an understanding of the Ni-YSZ anode redox degradation, the observations are used to propose an alternative anode design for improved redox tolerance. © 2010 Acta Materialia Inc.
Keywords: Environmental transmission electron microscopy (ETEM) ; Solid oxide fuel cell (SOFC) ; Reduction ; Oxidation ; Density functional theory (DFT) ; Oxide Reduction ; Oxidation ; Nio ; Interfaces ; Composite ; Diffusion ; Transport ; Hydrogen ; Growth ; Oxygen
Record created on 2010-10-18, modified on 2016-08-08