Metal-doped pyrochlore as novel electrode materials for intermediate temperature solid oxide fuel cell

In this study, the metal-doped La₂(Zr_1-xW _x)₂O₇ (LWZO) pyrochlore phases were synthesized by Pechini sol-gel method and characterized by X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The phase width of tungsten is x = 0.1 - 0.15. Temperature-programmed reduction (TPR) shows that the as-prepared products are stable under hydrogen atmosphere. XPS measurements revealed the valence state of La³⁺, Zr⁴⁺, and W^{(5+, 6+)}. The ionic- and electronic- conductivity of the 15% W-doped LWZO is 2.2×10^-3 to 1.9×10^-2 S/cm from 400 to 700 °C, which is better than YSZ and GDC over this temperature range. The LWZO is stable up to 1400 °C under reduced atmosphere. Bottom cells were fabricated with the LWZO electrolyte and GDC. The results shown that the La ₂(Zr_1-xW_x)₂O_7+δ have a good potential of becoming the electrolyte for IT-SOFCs.