Reuter D, Seitz K, Lunkenheimer P, Loidl A
Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg, Germany.
J Chem Phys. 2020 Jul 7;153(1):014502. doi: 10.1063/5.0012430.
We have performed a dielectric investigation of the ionic charge transport and the relaxation dynamics in plastic crystalline 1-cyano-adamantane (CNA) and in two mixtures of CNA with the related plastic crystals adamantane or 2-adamantanon. Ionic charge carriers were provided by adding 1% of Li salt. The molecules of these compounds have nearly globular shape and, thus, the so-called revolving-door mechanism assumed to promote ionic charge transport via molecular reorientations in other PC electrolytes should not be active here. Indeed, a comparison of the dc resistivity and the reorientational α-relaxation times in the investigated PCs reveals complete decoupling of both dynamics. Similar to other PCs, we find a significant mixing-induced enhancement of the ionic conductivity. Finally, these solid-state electrolytes reveal a second relaxation process, slower than the α-relaxation, which is related to ionic hopping. Due to the mentioned decoupling, it can be unequivocally detected and is not superimposed by the reorientational contributions as found for most other ionic conductors.
我们对塑性晶体1-氰基金刚烷（CNA）以及CNA与相关塑性晶体金刚烷或2-金刚烷酮的两种混合物中的离子电荷传输和弛豫动力学进行了介电研究。通过添加1%的锂盐来提供离子电荷载流子。这些化合物的分子具有近似球状的形状，因此，在其他塑性晶体电解质中假定通过分子重取向促进离子电荷传输的所谓旋转门机制在这里不应起作用。实际上，对所研究的塑性晶体中的直流电阻率和重取向α弛豫时间进行比较，结果表明这两种动力学完全解耦。与其他塑性晶体类似，我们发现混合会显著提高离子电导率。最后，这些固态电解质显示出第二个弛豫过程，其速度比α弛豫慢，这与离子跳跃有关。由于上述解耦现象，它能够被明确检测到，并且不会像大多数其他离子导体那样被重取向贡献所叠加。
