High-temperature interfacial reactivity of LaMnO3 +/-delta nanometric films on (100)YSZ

This paper aims to study the properties of the triple phase boundaries (TPB s) in the vicinity of the strontium-doped lanthanum manganite (cathode)/ytt ria-stabilized zirconia (electrolyte YSZ) interface in a solid oxide fuel c ell (SOFC), The LaMnO3+/-delta (LM) nanometric films deposited on (100)YSZ can be considered as a realistic and simple model of this half-cell. Low pressure metal-organic chemical vapour deposition was used to elaborate these films and to control the La/Mn ratio in the range 0.8-1.3 by using L a(tmhd)(3) and Mn(acac)(3) solid precursors at restricted temperature, pres sure and time conditions. The film characteristics have been studied: morph ology by SEM, chemical composition by energy-dispersive x-ray emission anal ysis and AES/scanning Auger microscopy and crystallography by x-ray diffrac tion and reflection high-energy electron diffraction, The half-cell performances at high temperature can be affected both by cati on diffusion into YSZ and by the formation of foreign phases. Data are pres ented on the interfacial reactivity as analysed by the above techniques: im portant changes in the YSZ morphology in the TPB regions and the formation of epitaxial Lanthanum zirconate are analysed for two La/Mn ratios (0.80 an d 1.30). Copyright (C) 2000 John Wiley & Sons, Ltd.