Compatibility analyses of BICUVOX.10 as a cathode in yttria-stabilized zirconia electrolytes for usage in solid oxide fuel cells

Abstract

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 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.

BICUVOX.1‐matrix composite electrolyte with yttria‐stabilized zirconia as an inert phase: SEM evaluation of the chemical stability under hydrogen atmosphere

“…In summary, this microstructural design with yttria‐stabilized zirconia particles along the grain boundaries of the BICUVOX.1 matrix does not effectively prevent decomposition. Other composite architectures such as a protective zirconia layer may likewise be inappropriate because of recent observations (Piva et al, ) with respect to the high reactivity between BICUVOX.1 and yttria‐stabilized zirconia at temperatures required to achieve a coating with good adhesive characteristics.…”

Oxide Ion Conductivity of Mechanically produced Calcia Stabilised Zirconia for Oxygen Sensing Applications

“…Response characteristics to the oxygen environment by the CSZ samples with different compositions studied by Zhou and Ahmad 8 shows that ion conductivity is related to oxygen sensing capabilities. For 15 mol% CaO composition prepared by Sol-Gel route at 700°C response was noted as quick and stable at various oxygen concentrations 33 . Conductivity measured in CSZ sample prepared by MA route is comparably lesser but significant enough for sensing applications for analyzing content of oxygen in exhaust gases of engines 23 .…”