复合BaTiO_3的Li_(0.5)La_(0.5)TiO_3固体电解质的制备和性能

Preparation and properties of Li_(0.5)La_(0.5)TiO_3 mixed with BaTiO_3

采用高温固相法合成具有高离子电导率的固体电解质Li0.5La0.5TiO3,并以Li0.5La0.5TiO3为母体,通过复合高介电纳米BaTiO3制得一系列不同复合量的复合电解质。对样品进行XRD、SEM分析,并应用交流阻抗技术测试其电导率。母体钛酸镧锂(LLTO)为存在超结构的立方晶体,30℃时晶粒电导率为1.1×10-3S/cm。在复合样品中,LLTO与BaTiO3形成具有棒状结构的钙钛矿型固溶体(Li、La、Ba)TiO3。在低的复合量下(小于10%),复合样品的晶粒电导率比纯样晶粒电导率高。120℃时,母体与复合5%样品的晶粒电导率分别为0.84×10-2、2.39×10-2S/cm,活化能分别为0.22、0.40eV。

A pure phase of the solid electrolyte Li0.5La0.5TiO3（LLTO） was prepared by the conventional solid-state rea-ction method,and those LLTO powders were mixed with BaTiO3 nano particles to prepare the composite.The microstructure morphology and conductivity properties of the composite were investigated by X-ray diffraction,scanning electron microscope and AC impedance method.The grain conductivity of LLTO bulk sample is 1.1×10^-3 S/cm.The perovskite-type solid solution（Li,La,Ba）TiO3 rods can be found in the composite.At the lower dopant concentration（〈10%）,the grain conductivity of the composite electrolyte is higher than that of the pure LLTO.The grain conductivities of LLTO and LLTO doped with 5 % BaTiO3 at 120 ℃ are 0.84×10^-2 S/cm and 2.39×10^-2 S/cm respectively.