Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1277371 | International Journal of Hydrogen Energy | 2011 | 9 Pages |
Several tungsten bronzes were investigated for use in solid oxide fuel cell (SOFC) anodes. Composite anodes were prepared by infiltration of the precursor salts into a porous yttria-stabilized zirconia (YSZ) scaffold to produce 40-wt% composites with bronze compositions of Na0.8NbyW1−yO3−δ (y = 0, 0.3, 0.7, and 1), K0.5WO3−δ, Cs0.2WO3−δ, and Rb0.2WO3−δ. XRD data showed that the bronze structures were formed following reduction in humidified H2 at 873 K but that the bronzes were partially reduced to metallic W above 1073 K. Composite conductivities as high as 130 S/cm were observed at 973 K for the Na0.8WO3−δ-YSZ composite but substitution of Nb significantly decreased the conductivity without increasing the temperature at which tungsten was reduced. The impedance of Na0.8WO3−δ-YSZ anodes in humidified H2 at 973 K was greater than 1.0 Ω cm2 but this decreased to approximately 0.3 Ω cm2 upon the addition of 1-wt% Pd for catalytic purposes. The possible use of anodes based on tungsten bronzes is discussed.
► Infiltration procedures were used to prepare SOFC anodes from various tungsten bronzes. ► Bronze-YSZ composites showed conductivities as high as 130 S/cm at 973 K. ► The Na-W bronze was stable in humidified H2 below 1023 K but could be reduced to metallic W above 1073 K. ► As with other ceramic anodes, the addition of a catalyst was required to achieve low anode impedance.