Structure and Dynamics of Ionic Liquids Confined in Amorphous Porous Chalcogenides

Besides the abundant literature on ionic liquids in porous silica and carbon, the confinement of such intriguing liquids in porous chalcogenides has received very little attention. Here, molecular simulation is employed to study the structural and dynamical properties of a typical ionic liquid confined in a realistic molecular model of amorphous chalcogenide with various pore sizes and surface chemistries. Using molecular dynamics in the isobaric-isothermal (NPT) ensemble, we consider confinement conditions relevant to real samples. Both the structure and self-dynamics of the confined phase are found to depend on the surface-to-volume ratio of the host confining material. Consequently, most properties of the confined ionic liquid can be written as a linear combination of surface and bulk-like contributions, arising from the ions in contact with the surface and the ions in the pore center, respectively. On the other hand, collective dynamical properties such as the ionic conductivity remain close to their bulk counterpart and almost insensitive to pore size and surface chemistry. These results, which are in fair agreement with available experimental data, provide a basis for the development of novel applications using hybrid organic-inorganic solids consisting of ionic liquids confined in porous chalcogenides.