Plastic-crystalline solid-state electrolytes: Ionic conductivity and orientational dynamics in nitrile mixtures.
Plastic-crystalline solid-state electrolytes: Ionic conductivity and orientational dynamics in nitrile mixtures.
复制标题
DOI：
10.1063/1.5110404
复制
发表时间：
2019-05
期刊：
影响因子：
--
通讯作者：
D. Reuter;P. Lunkenheimer;A. Loidl
中科院分区：
文献类型：
--
作者：
D. Reuter;P. Lunkenheimer;A. Loidl
许多塑料晶体，分子固体与长程，质心晶体秩序，但动态无序的分子取向，是已知的表现出异常高的离子电导率。这使得它们成为固态电解质应用的有希望的候选者，例如，电池。有趣的是，发现两种不同的塑性结晶材料的混合可以显著提高离子直流电导率，这是电化学应用的重要基准量。一个例子是不同腈与丁二腈的混合物，后者是最突出的塑性结晶离子导体之一。然而，到目前为止，只有少数这样的混合物进行了研究。在本工作中，我们研究了丁二腈与丙二腈，己二腈和庚二腈的混合物，其中1摩尔。%的Li离子。利用差示扫描量热法和介电谱，我们研究这些系统的相行为和偶极和离子动力学。我们特别解决的混合诱导的离子电导率的增强和耦合的平移离子迁移率的分子重新取向的动力学，可能通过一个“旋转门”的机制。
Many plastic crystals, molecular solids with long-range, center-of-mass crystalline order but dynamic disorder of the molecular orientations, are known to exhibit exceptionally high ionic conductivity. This makes them promising candidates for applications as solid-state electrolytes, e.g., in batteries. Interestingly, it was found that the mixing of two different plastic-crystalline materials can considerably enhance the ionic dc conductivity, an important benchmark quantity for electrochemical applications. An example is the admixture of different nitriles to succinonitrile, the latter being one of the most prominent plastic-crystalline ionic conductors. However, until now, only few such mixtures were studied. In the present work, we investigate succinonitrile mixed with malononitrile, adiponitrile, and pimelonitrile to which 1 mol. % of Li ions was added. Using differential scanning calorimetry and dielectric spectroscopy, we examine the phase behavior and the dipolar and ionic dynamics of these systems. We especially address the mixing-induced enhancement of the ionic conductivity and the coupling of the translational ionic mobility to the molecular reorientational dynamics, probably arising via a "revolving-door" mechanism.