A novel Gd3+ and Yb3+ co-doped ceria-sulphate composite electrolyte for intermediate-temperature fuel cells

Abstract

In this study, Yb3+ and Gd3+ co-doped CeO2 and the corresponding (Li/K)2SO4 composite electrolyte were prepared. The structures and morphologies of Ce0.8Yb0.1Gd0.1O2-α and Ce0.8Yb0.1Gd0.1O2-α-Li2SO4–K2SO4 were investigated using X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). The conductivity of Ce0.8Yb0.1Gd0.1O2-α (1550 °C) as a function of time during humidification in a nitrogen atmosphere at 700 °C was investigated. The log(σT) vs. 1000T−1 plots, logσ vs. log(pO2) curves, and fuel cell performances of Ce0.8Yb0.1Gd0.1O2-α (1550 °C) and Ce0.8Yb0.1Gd0.1O2-α-Li2SO4–K2SO4 (1550 °C) were investigated. At 700 °C, Ce0.8Yb0.1Gd0.1O2-α-Li2SO4–K2SO4 (1550 °C) showed a power density of 197 mW cm−2, which is five times higher than that of Ce0.8Yb0.1Gd0.1O2-α (1550 °C).