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Abstract: The effects of MoO3 concentration on the sintering and electrical properties of Ce0.8Nd0.2O1.9 + 500 ppm SiO2 (NDCSi) and (Ce0.8Nd0.2O1.9)1 − x (MoO3) x  + 500 ppm SiO2 ( x = 0.01, 0.02, 0.03, 0.04, 0.05, NDCSi + 1MoO3, NDCSi + 2MoO3, NDCSi + 3MoO3, NDCSi + 4MoO3, NDCSi + 5MoO3) prepared through a modified sol–gel method were systematically investigated. The structures and ionic conductivities were characterized by XRD, FE-SEM and EIS. The results indicated a sharp increase in densification and conductivity for the system of NDCSi containing small amount of MoO3. It shows that NDCSi + 3MoO3 exhibited much higher relative density (RD = 96%), higher conductivity (σ t = 1.25 × 10−2 S cm−1 at 600 °C) and lower activation energy (E a = 0.81 eV) compared with NDCSi and the other MoO3 doped-NDCSi samples. Furthermore, MoO3 could be used as an effective sintering aid and a grain boundary scavenger for NDCSi system. And we obtained the optimal amount of the MoO3 is 3 mol%. [Copyright &y& Elsevier]

In order to optimize the electrical properties of co-doped ceria electrolytes, Ce 0.8 Ca 0.15 Sm 0.05 O 2− δ (CCS) sintered at different temperatures (1150 °C, 1200 °C, 1250 °C, 1300 °C and 1350 °C for 8 h) have been prepared and systematically investigated. It is found that among these samples sintered at different conditions, the electrical conductivity ( σ ) measured at 800 °C can be ranked as: CCS 1250 °C : σ CCS 1250 ° C 800 ° C = 2.38 × 10 −2 S cm −1 > CCS 1200 °C : σ CCS 1200 ° C 800 ° C = 1.81 × 10 −2 S cm −1 > CCS 1150 °C : σ CCS 1150 ° C 800 ° C = 1.50 × 10 −2 S cm −1 > CCS 1300 °C : σ CCS 1300 ° C 800 ° C = 1.26 × 10 −2 S cm −1 > CCS 1350 °C : σ CCS 1350 ° C 800 ° C = 0.68 × 10 −2 S cm −1 . The electrical conductivity of CCS increases with the increase of sintering temperatures, and the 1250 °C-sintered sample presents the highest conductivity because of the best microstructures. However, the electrical conductivity of CCS decreases when the sintering temperatures goes beyond 1250 °C. We attribute this to the phase instability. It reveals that microstructures and the phase stability have important effects on the optimization of electrical properties for the co-doped ceria electrolytes. [ABSTRACT FROM AUTHOR]

Abstract: The effect of small addition of different sintering aids (MoO3 and WO3) on the electrical properties of Ce0.9Nd0.1O2−δ has been investigated. The (Ce0.9Nd0.1)1−x M x O2−δ (x = 0.0; M = Mo, W, x = 0.01; Ce0.9Nd0.1O2−δ : NDC, (Ce0.9Nd0.1)0.99Mo0.01O2−δ : NDCMo; (Ce0.9Nd0.1)0.99W0.01O2−δ : NDCW) solid solutions were prepared and characterized. The X-ray diffraction patterns indicate that all the samples are single phases with a cubic fluorite structure. Moreover, from the field-emission scanning electron microscopy results, it is found (Ce0.9Nd0.1)0.99M0.01O2−δ (M = Mo, W) sintered at 1300 °C for 15 h have better sinterability than Ce0.9Nd0.1O2−δ . The total conductivity by electrochemical impedance spectroscopy are ranked as: NDCW  > NDCMo  > NDC measured at 700 °C, which is attributed to microstructures. It can be concluded that MoO3 and WO3 are both effective and WO3 seems to be more potential as sintering aids on the optimization of electrical properties for ceria-based electrolytes. [Copyright &y& Elsevier]