溶胶－凝胶法制备Na_5YSi_4O_（12）及其离子导电性质

用溶胶－凝胶方法制备了钠快离子导体Ｎａ_５ＹＳｉ_４Ｏ_（１２）（简称ＮＹＳ）的纯相，应用交流阻抗谱技术测定了样品的离子电导和离子导电活化能，用扫描电子显微镜对用不同方法制备的样品烧结体表面进行了观察。与传统固相反应法制备的ＮＹＳ离子导体相比，用溶胶－凝胶方法制备的ＮＹＳ烧结体具有较好的界面效应。

Synthesis of Na_5YSi_4O_(12)by Sol-Gel Method and Its Ionic Conductivity

High ionically conducting single-phase NYS samples have been prepared by both the conventional solid state reaction and the Sol-Gel method.Because of the high sensitivity of phase purity and ionic conductivity of the samples to the composition of starting materials,we carefully controlled the procedure of syntheses in order to exclude impurity phases,i.e.Na3YSi3O9 and Na9YSi6O13.Ionic conductivity and conducting activation energy of samples prepared by these two methods have been determined by means of AC impedance technique.From the analysis of their impedance spectra,we know that the sample prepared by conven tional solid state reaction has some what lower ionic conductivity and higher conducting acti vation energy. On the other hand,ionic conductivity of the sample prepared by Sol-Gel method is comparatively higher,and its conducting activation energy is lower.In accordance with the ionic conducting property,the microstructure observed by SEM of these two sam ples shows big difference,that is, the latter has small and uniform grains which connected more closely but the former has large and nonuniform grains packed loosely.Compared with the former,the latter has more conducting paths for the mobile ions,hence higher ionic conductivity.