Na-β''-Al₂O₃固体电解质的制备与表征

Preparation and Characterization of Na-β''-Al₂O₃ Solid Electrolytes

摘要: 氧化物型钠离子固态电解质Na-β''-Al₂O₃具有较高的高温离子电导率，并且已经实现了高温环境下的商业化应用。然而，Na-β''-Al₂O₃的合成通常需要在较高的温度环境下进行，但是高温会造成Na元素的大量挥发损失，使得样品的实际离子电导率降低。因此，如何适量控制Na元素的添加量来弥补烧结过程中的损失是一个重要的课题。在本文中，我们采用固相反应法，通过控制Na₂CO₃的过量含量(0 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%)合成了固态电解质Na₂Li_0.3Al_10.66O_17.14。实验发现，与Na₂CO₃未过量的样品相比，Na₂CO₃过量15 wt%的样品具有较高的离子电导率(6.93 × 10⁻⁴ S/cm)，比未过量的样品提高了6倍，相对密度为(97.91%)。

Abstract: Oxide-based Na-β''-Al₂O₃ solid electrolytes possess relatively high ionic conductivities at high temperatures, thereby realizing good commercial applications under high temperature environment. However, in most cases, high-temperature are required for the synthesis of Na-β''-Al₂O₃, the high-temperature synthesis of Na-β''-Al₂O₃ may lead to the deficiency of Na and then cause the reduction of ionic conductivity. Therefore, how to control the amount of Na element to make up for the loss in sintering process is an important topic. In this study, the solid-state reaction method is used to synthesize Na₂Li_0.3Al_10.66O_17.14 solid electrolytes with a series of overdosed Na (0 wt%, 5 wt%, 10 wt%, 15 wt%, and 20 wt%). Their microstructure and electrical properties are comparatively investigated. The results indicate that 15 wt% overdosed Na sample shows the largest relative density (97.91%) and the highest ionic conductivity, 6.93 × 10⁻⁴ S/cm, which is 6 times higher than that for the non-overdosed sample.