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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]

A series of novel composite electrolytes based on 20 mol% Gd doped CeO 2 with varying amounts of (Li/Na) 2 SO 4 have been synthesized. X-ray diffraction, thermogravimetry and differential scanning calorimetry, scanning electron microscope and transmission electron microscope were applied to characterize the phase components and microstructures of the composite electrolytes. Their ionic conductivities were determined by AC impedance spectroscopy. It has been found that the optimum sintering temperature and sulphate content for the composite electrolyte is 870 °C and 20 wt% (Li/Na) 2 SO 4 , respectively. Above 550 °C, a sharp increase in conductivity occurred, which can be interpreted as superionic phase transitions in the interface phases between GDC and sulphates. Both the high ionic conductivities above the transition temperature, 0.191, 0.298 and 0.372 S cm −1 at 550, 650 and 750 °C respectively, and low activation energy (0.303 eV) highlight composite GDC-20 wt% (Li/Na) 2 SO 4 a promising electrolyte candidate for application in intermediate temperature solid oxide fuel cells. [ABSTRACT FROM AUTHOR]