| Abstract Scope |
Various materials, such as superionic materials (SIM), lithium-ion batteries (LIB), and metal-organic frameworks (MOF), possess mobile atoms with liquid-like behavior in the rigid frameworks of other atoms. We perform large-scale molecular dynamics simulations (MDS) based on machine-learning interatomic potentials fitted from ab initio MDS to explore mobile atoms' detailed structures and dynamics. We define the three-dimensional atomic density distribution function (ADDF) to provide detailed structures of mobile atoms and use the Arrhenius equation to study mobile atoms' diffusion dynamics. We have complete studies for following materials (i) SIM: Ag2S, Ag8SiTe6, Cu2S, and Zn3.6+xSb3; (ii) LIB: LixCoO2, Li6+xPS5Cl, Cu7+xPS6; (iii) MOF: H2O, CO2, N2, CH4 diffusion on [Ca(C4O4)(H2O)]. Our results indicate that the Arrhenius equation describes the diffusion behaviors of the various mobile atoms well, with activation barriers ranging from 0.1 to 0.3 eV. The small diffusion barriers provide the fundamental origin for the liquid behaviors of mobile atoms. |