Compatibility analyses of BICUVOX.10 as a cathode in yttria-stabilized zirconia electrolytes for usage in solid oxide fuel cells
AUTOR(ES)
Piva, Roger Honorato, Piva, Diógenes Honorato, Souza, Marcelo Tramontin, Morelli, Márcio Raymundo
FONTE
Mat. Res.
DATA DE PUBLICAÇÃO
30/09/2014
RESUMO
Copper-substituted bismuth vanadate has been considered a promising material for composite cathodes in SOFC. However, high reactivity of BICUVOX.10 towards the electrolytes still has been its greatest shortcoming. This paper describes reactions between BICUVOX.10 and yttria-stabilized zirconia (YSZ) electrolytes. Secondary phases formed were evaluated by X-ray diffraction, scanning electron microscopy and a.c. impedance spectroscopy. A deleterious interaction between BICUVOX.10 and YSZ was observed, mainly regarding the yttrium depletion from ZrO2 lattice through reaction with VO2.5, resulting in YVO4 phase nucleation and destabilization of the tetragonal and cubic ZrO2 polymorphs to monoclinic. The ZrO2 destabilization and YVO4 nucleation are related phenomena and were interpreted through a theoretical mechanism using charge-compensating dopants description. Thus, these reactions were seen as detrimental to the cathode/electrolyte contact, especially regarding the highly resistive layer formed in the BICUVOX.10/YSZ junction, discouraging further usage of BICUVOX.10 as a cathode in yttria-stabilized zirconia electrolytes.
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