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

In this study, Gd0.1Ln0.1Ce0.8O2-& alpha; (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 degrees C and 1450 degrees 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 x 10-2 S cm- 1 and 3.4 x 10-2 S cm- 1 at 750 degrees 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 & mu;m) using Ba0.5Sr0.5Co0.8Fe0.2O3-& delta; (BSCF) as the cathode were 296.2 mW cm-2, 406.2 mW cm-2 and 529.1 mW cm-2 at 650 degrees C, 700 degrees C and 750 degrees C, respectively.

Automated summary

In this study, Gd0.1Ln0.1Ce0.8O2-& alpha; (Ln = Er, Yb) material was synthesized by a glycine-nitrate combustion method, and the effects of calcining temperature, codoped ion, and sintering additive on the structure, grain size, and intermediate-temperature electrochemical properties were investigated. The morphology and density of the ceria electrolytes were significantly affected by the addition of ZnO as a sintering additive. The conductivities of 1350-GEDC-ZnO and 1350-GYDC-ZnO were 4.4 x 10-2 S cm-1 and 3.4 x 10-2 S cm-1, respectively, at 750 degrees C. The output performance of the intermediate-temperature thin film fuel cell using the best electrical property electrolyte was also studied, and the maximum power densities were obtained at 650 degrees C, 700 degrees C, and 750 degrees C.