Ce_(0.8)Nd_(0.2)O_(1.9)-La_(0.95)Sr_(0.05)Ga_(0.9)Mg_(0.1)O_(3-δ)固体复合电解质的结构和电性能

Structure and Electrical Properties of Ce_(0.8)Nd_(0.2)O_(1.9)-La_(0.95)Sr_(0.05)Ga_(0.9)Mg_(0.1)O_(3-δ) Solid Composite Electrolytes

采用溶胶-凝胶法分别制备La0.95Sr0.05Ga0.9Mg0.1O3-δ(LSGM)和Ce0.8Nd0.2O1.9(NDC)电解质,并在NDC溶胶中加入0-15%(w,质量分数)的LSGM预烧粉体制得NDC-LSGM复合电解质,研究不同质量比复合电解质的结构和电性能.采用X射线衍射(XRD)、场发射扫描电子显微镜(FE-SEM)和X能量色散谱仪(EDS)对样品进行结构表征,交流(AC)阻抗谱测试样品导电性能.结果表明:NDC-LSGM复合体系主要由立方萤石结构相、钙钛矿结构相和杂质相组成;LSGM的添加可促进晶粒的生长,产生大量相界面,清除或降低SiO2有害影响,明显提高晶界导电性;LSGM质量分数为10%的样品NL10具有最高晶界电导率和总电导率,400°C时NL10的晶界电导率σgb和总电导率σt分别为12.15×10-4和3.49×10-4S cm-1,与NDC的σgb(1.41×10-4S cm-1)和σt(1.20×10-4S cm-1)相比分别提高了7.62和1.91倍,总电导率的提高主要归因于晶界电导率的影响.

Ce0.8Nd0.2O1.9（NDC） （NDC） and La0.95Sr0.05Ga0.9Mg0.1O3-δ（LSGM）（LSGM） electrolytes were each prepared using a sol-gel method. NDC-LSGM composite electrolytes were then prepared by adding 0-15% （w, mass fraction） precalcined LSGM powders to NDC sols. The microstructure and phase composition of the pellets were characterized using X-ray diffraction （XRD）, field-emission scanning electron microscopy （FE-SEM）, and energy- dispersive X-ray spectroscopy （EDS）. The electrical conductiviUes of the pellets were measured using altemative current （AC） impedance spectroscopy. The results showed that all the composites were composed of the cubic fiuodte structure, perovskite structure, and secondary phases. The LSGM additive significantly promoted grain growth. The grain boundary conduction increased greatly as a result of the presence of phase interfaces and mitigation of the harmful effects of SiO2 impurities. NL10 was found to have the highest conductivities （agb=12.15x 10-4 S. cm^-1, σt=3.49x 10-4 S· cm^-1 at 400 ℃C）; these values are 7.62 and 1.91 times higher than those of NDC （σgb=1.41 x 10-4 S. cm^-1, a,=1.2x 10^-4 S· cm^-1）. The enhancement of the total conductivity of NL10 is mainly attributed to the large increase in grain boundary conductivity.