Sørensen S S, Smedskjaer M M, Micoulaut M
Department of Chemistry and Bioscience, Aalborg University, Aalborg 9220, Denmark.
Laboratoire de Physique Théorique de la Matière Condensée, CNRS UMR 7600, Sorbonne Université, 4 Place Jussieu, Paris Cedex 05 75252, France.
J Phys Chem B. 2023 Nov 30;127(47):10179-10188. doi: 10.1021/acs.jpcb.3c02909. Epub 2023 Nov 17.
Classical molecular dynamics is used to study the dynamics of alkali ions in a promising fast ion conductor glass system, i.e., NaS-SiS. Diffusion in such thiosilicates is found to display various salient features of alkali silicates, i.e., channel-like diffusion with typical length scales emerging as the temperature is decreased to the glassy state, and Arrhenius behavior for both Na ion diffusivity and calculated conductivity. The dynamics appears, however, to be largely heterogeneous as manifested by fast and slow Na ion motion at intermediate times, both in the high-temperature liquid and in the glassy state. In the former, a diffusion-limited regime is found due to the increased motion of the network-forming species that limits the Na ion dynamics, whereas at low temperatures, the typical dynamical heterogeneities are recovered as observed close to the glass transition.
经典分子动力学被用于研究一种有前景的快离子导体玻璃体系——NaS-SiS中碱金属离子的动力学。发现在此类硫代硅酸盐中的扩散表现出碱金属硅酸盐的各种显著特征，即随着温度降低至玻璃态出现具有典型长度尺度的通道状扩散，以及钠离子扩散率和计算得到的电导率均呈现阿仑尼乌斯行为。然而，动力学在很大程度上似乎是不均匀的，这在高温液体和玻璃态的中间时刻均表现为钠离子的快速和慢速运动。在前者中，由于网络形成物种运动增加限制了钠离子动力学，发现了一个扩散受限区域，而在低温下，如在接近玻璃转变时所观察到的，典型的动力学不均匀性得以恢复。
