CAJ | 학술논문

The properties of LSO-SDC composite electrolytes prepared by the mixed powder with different LSO/SDC mass ratios were studied. The apatite-type lanthanum silicates La10Si6O27 (LSO) and Sm0.2Ce0.8O1.9 (SDC) were synthesized via sol-gel process and glycine-nitrate process (GNP), respectively. The phase structure, microstructure, relative density, thermal expansion properties and oxygen ion conductivity of the samples were investigated by means of techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Archimedes method, dilatometer, and AC impedance spectroscopy. The results showed that SDC addi-tion to the samples could enhance the density of the samples. However, the LSO-SDC composite electrolyte sintered at 1550 oC was over sintering when the SDC content was 50 wt.%. At the lower content of SDC (0–10 wt.%), the decrease of conductivity was pre-dominantly attributed tothereducing concentration of carriers. However, the conductivities of the composite electrolytes increased with the increasing SDC content (10 wt.%–40 wt.%) because of the enhanced percolation of highly conductive SDC component in the microstructure of composite electrolytes. In addition,the dependence of conductivity onp(O2) showed that LSO-SDC composite electrolytes were stable in the examined range ofp(O2).