Effect of ZnO on the intermediate-temperature electrochemical properties of Gd0.1Ln0.1Ce0.8O2-α (Ln = Er, Yb) for solid oxide membrane fuel cells

Abstract

In this study, Gd0.1Ln0.1Ce0.8O2-α (Ln = Er, Yb) was prepared by a glycine-nitrate combustion method. The influences of the calcining temperature, codoped ion and addition of sintering additive on the structures, grain sizes and intermediate-temperature electrochemical properties of the samples were investigated. The micromorphologies and crystal structures of the synthesized samples were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The relationship between the conductivity and oxygen partial pressure and the H2/O2 fuel cell was also studied. The XRD results showed that the samples were single-phase cubic fluorite structures after being calcined at 1350 °C and 1450 °C. The sintering additive of ZnO can significantly affect the morphology and density of the obtained ceria electrolytes. The conductivities of 1350-GEDC-ZnO and 1350-GYDC-ZnO reached 4.4 × 10−2 S cm−1 and 3.4 × 10−2 S cm−1 at 750 °C, respectively. The output performance of the intermediate-temperature thin film fuel cell was also studied by applying the electrolyte with the best electrical property. The maximum output power densities of the 1350-GEDC-ZnO membrane (15 μm) using Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) as the cathode were 296.2 mW cm−2, 406.2 mW cm−2 and 529.1 mW cm−2 at 650 °C, 700 °C and 750 °C, respectively.