二价离子替代的Nasicon及其应用研究

Study on M￣(2 +)-SubstitIited Nasicons and Their Applications

含二价阳离子的Ｎａｓｉｃｏｎ，Ｍ￣（２＋）Ｎａｓｉｃｏｎ（Ｍ＝Ｍｇ、Ｃａ、Ｓｒ、Ｚｎ）可由母体Ｎａ＿３Ｚｒ＿２Ｓｉ＿２ＰＯ＿（１２）（Ｎａｓｉｃｏｎ）为起始原料与相应的二价离子的盐浓液或熔盐进行离子交换而制得。Ｘ射线衍射分析结果表明离子交换后的产物Ｍ￣（２＋）－Ｎａｓｉｃｏｎ大多保持原母体的Ｃ＿（２／ｃ）结构。交流阻抗技术测定的电导率数据显示含不同的二价替代离子的Ｎａｓｉｃｏｎ的电导率相差甚大。其中最好的是Ｍｇ￣（２＋）－Ｎａｓｉｃｏｎ，其电导率在４００℃时可达到１．４８×１０￣（－２）Ｓ／ｃｍ。Ｍｇ￣（２＋）－Ｎａｓｉｃｏｎ用作微功率固态电池Ｍｇ／ＣｕＣｌ的电解质，该电池的开路电压为２．０７Ｖ，短路电流为１ｍＡ。平均放电电压为１．６Ｖ，电池的放电容量是３．４ｍＡＨ。

M￣(2+)-Substituted Nasicons were prepared by using Nasicon(Na_3Zr_2Si_2PO_(12))as astarting material whose Na￣(+)could be reversibly ion-exchanged with a variety of divalent cations,e,g.Mg￣(2+),Ca￣(2+),Sr￣(2+) and Zn￣(2+) in the meIt or the solutionof their salts. The results of XRD analysis showed that theM￣2+)-substituted Nasicons had thesame structure asthe original Nasicon with the space group of C_(2/c)The best conductivity,having the value of 1.48×10￣(-2)S/cm at 400℃measured by an a.c.impedancetechnique, for Mg￣(2+) -substituted Nasicons is that ofMg￣(2+)-substituted one. The Mg￣(2+)-Nasicon has beenused as a solid electrolyte in a Mg/CuCl solid statebattery characterized with the open circuit voltage of 2.07V;the short circuit current of lmA,the mean(M discharge voltage of 1.6V and the cell capacity of 3.4mAH.