MgO或Fe_2O_3掺杂Ce_(0.8)Nd_(0.2)O_(1.9)固体电解质的结构和电性能

Structure and Electrical Properties of MgO or Fe_2O_3-Doped Ce_(0.8)Nd_(0.2)O_(1.9) Solid Electrolytes

采用溶胶-凝胶法合成SiO2含量为0.05%(w,质量分数)的Ce0.8Nd0.2O1.9(NDC)粉体(NDCSi).分别将0-2.0%(x,摩尔分数)的MgO或FeO1.5添加到NDCSi粉体中,经10MPa压片后于1300°C烧结6h.采用X射线衍射(XRD)、拉曼(Raman)光谱和场发射扫描电子显微镜(FE-SEM)对样品进行结构表征.采用交流(AC)阻抗谱测试样品导电性能.结果表明:所有样品均呈现单一立方萤石结构.MgO或Fe2O3掺杂于NDCSi体系,均可提高材料的致密度,降低烧结温度,提高材料的晶界电导率和总电导率.掺杂MgO或Fe2O3样品的相对密度(>93%)高于NDC或NDCSi(约86%),有效促进了样品致密化.掺杂Fe2O3或MgO的样品(NDCSi+0N.D5FCeSOi样1.5或品总ND电C导Si率+2(.10.M1×g1O0)-具3S有·c最m高-1)电的导5.7率和,525.60倍°C.M时g总O电或导Fe率2O分3掺别杂是于6.N3D×C10S-i3样或品2.对9×晶10界-3电S·导c率m-的1,是影响比晶粒电导率更明显.MgO或Fe2O3掺杂于NDCSi均具有烧结助剂和晶界清除剂的双重作用,但清除杂质SiO2的机制不同.

A precursor powder of Ce 0.8 Nd 0.2 O 1.9（NDC） containing 0.05%（mass fraction） SiO 2 as an impurity（NDCSi） was doped with 0-2.0%（molar fraction） MgO or FeO 1.5 via the sol-gel method.After pressing at 10 MPa,the samples were sintered at 1300 ℃ for 6 h.The structure of the pellets was characterized by X-ray diffraction（XRD）,Raman spectroscopy,and field emission scanning electron microscopy（FE-SEM）.The electrical conductivity of the pellets was measured using AC impedance spectroscopy.All of the samples exhibited a cubic fluorite structure.Doping with MgO or Fe2O3 lowered the sintering temperature,and increased the density,grain boundaries and total conductivity of NDCSi.The relative density of the samples doped with Fe2O3 or MgO（〉93%） was higher than those of NDC or NDCSi（about 86%）,suggesting these dopants are effective at promoting densification.NDCSi ＋ 0.5FeO 1.5 and NDCSi ＋ 2.0MgO samples exhibited the highest conductivities of 0.63 × 10-2 and 0.29 × 10-2 S cm-1,respectively,which are 5.7 and 2.6 times larger than that of NDCSi（0.11×10-2 S cm-1） at 550 ℃.Doping with MgO or Fe2O3 had a larger effect on the grain boundary conductivity of SDCSi than the bulk conductivity.These results indicate that MgO and Fe2O3 are effective sintering aids as well as grain boundary scavengers with different mechanisms.