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

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... ved, mainly regarding the yttrium depletion from ZrO 2 lattice through reaction with VO 2.5 , resulting in YVO 4 phase nucleation and destabilization of the tetragonal and cubic ZrO 2 polymorphs to monoclinic. The ZrO 2 destabilization and YVO 4 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.