The interfacial resistance of Ni-Y2O3-stabilized ZrO2 (Ni-YSZ) anodes on YSZ electrolytes has been reduced by inserting thin interfacial layers of TiO2-doped YSZ (YZT) or Y2O3-doped CeO2 (YDC). Impedance spectroscopy measurements at temperatures ranging from 600 to 750°C typically showed a high frequency arc (HFA) and a low frequency arc (LFA). The HFA was reduced by the addition of either interlayer, with a larger reduction for YDC. This presumably resulted from enhanced charge transfer due to the mixed conductivity and/or enhanced redox reaction rate of the interfacial layer. The LFA, which was apparently related to mass-transport processes, grew with decreasing YSZ surface roughness and increasing interlayer thickness. The overall interfacial resistance was minimized for layer thicknesses of ∼0.5 μm. The lowest interfacial resistances in 97% H2 + H2O, 0.13 Ω cm2 at 750°C, and 0.29 Ω cm2 at 600°C, were obtained with 0.5 μm thick YDC interfacial layers.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry