Metal-doped Pyrochlore as Novel Electrode Materials For Intermediate Temperature Solid Oxide Fuel Cell

Abstract

In this study, the metal-doped La-2(Zr1-xWx)(2)O-7 (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+,W- 6+). The ionic- and electronic-conductivity of the 15% W-doped LWZO is 2.2x10(-3) to 1.9x10(-2) S/cm from 400 to 700 degrees C, which is better than YSZ and GDC over this temperature range. The LWZO is stable up to 1400 degrees C under reduced atmosphere. Bottom cells were fabricated with the LWZO electrolyte and GDC. The results shown that the La-2(Zr1-xWx)(2)O7+delta have a good potential of becoming the electrolyte for IT-SOFCs.