Yb2O3 Doped Zr0.92Y0.08O2-α(8YSZ) and Its Composite Electrolyte for Intermediate Temperature Solid Oxide Fuel Cells

Abstract

Yb3+ and Y3+ double doped ZrO2 (8YSZ+4Yb2O3) samples were synthesized by a solid state reaction method. Moreover, 8YSZ+4Yb2O3-NaCl/KCl composites were also successfully produced at different temperatures. The 8YSZ+4Yb2O3, 8YSZ+4Yb2O3-NaCl/KCl (800 °C), and 8YSZ+4Yb2O3-NaCl/KCl (1000 °C) samples were characterized by x–ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that a dense composite electrolyte was formed at a low temperature of 800 °C. The maximum conductivities of 4.7 × 10−2 S·cm−1, 6.1 × 10−1 S·cm−1, and 3.8 × 10−1 S·cm−1 were achieved for the 8YSZ+4Yb2O3, 8YSZ+4Yb2O3-NaCl/KCl (800 °C), and 8YSZ+4Yb2O3-NaCl/KCl (1000 °C) samples at 700 °C, respectively. The logσ~log (pO2) plot result showed that the 8YSZ+4Yb2O3-NaCl/KCl (800 °C) composite electrolyte is a virtually pure ionic conductor. An excellent performance of the 8YSZ+4Yb2O3-NaCl/KCl (800 °C) composite was obtained with a maximum power density of 364 mW·cm−2 at 700 °C.