Polymer-based solid-like gel electrolytes have emerged as a promising alternative to improve battery performance. However, there is a scarcity of studies on the behavior of these media at the electrochemical interface. In this work, we report classical MD simulations of ternary polymer electrolytes composed of poly(ethylene oxide), a lithium salt [lithium bis(trifluoromethanesulfonyl)imide], and different ionic liquids [1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide] confined between two charged and uncharged graphene-like surfaces. The molecular solvation of Li⁺ ions and their diffusion as well as the polymer conformational picture were characterized in terms of the radial distribution functions, coordination numbers, number density profiles, orientations, displacement variance, polymer radius of gyration, and polymer end-to-end distance. Our results show that the layering behavior of the ternary electrolyte in the interfacial region leads to a decrease of Li⁺ mobility in the direction perpendicular to the electrodes and high energy barriers that hinder lithium cations from coming into direct contact with the graphene-like surface. The nature of the ionic liquid and its concentration were found to influence the structural and dynamic properties at the electrode/electrolyte interface, the electrolyte with low amounts of the pyrrolidinium-based ionic liquid being that with the best performance since it favors the migration of Li⁺ cations toward the negative electrode when compared to the imidazolium-based one.

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电化学界面处的三元固体聚合物电解质：计算研究

基于聚合物的固体凝胶电解质已成为提高电池性能的有前途的替代品。然而，对这些介质在电化学界面上的行为的研究很少。在这项工作中，我们报告了由聚环氧乙烷、锂盐[双(三氟甲磺酰基)亚胺锂]和不同离子液体[1-丁基-1-甲基吡咯烷鎓双(三氟甲磺酰基)亚胺组成的三元聚合物电解质的经典MD模拟和1-乙基-3-甲基咪唑鎓双(三氟甲磺酰基)亚胺]限制在两个带电和不带电的类石墨烯表面之间。 Li ⁺离子的分子溶剂化及其扩散以及聚合物构象图通过径向分布函数、配位数、数密度分布、方向、位移方差、聚合物回转半径和聚合物端对角来表征结束距离。我们的结果表明，界面区域三元电解质的分层行为导致垂直于电极方向的Li ⁺迁移率降低，并且高能垒阻碍了锂阳离子与类石墨烯表面的直接接触。研究发现离子液体的性质及其浓度会影响电极/电解质界面的结构和动力学性质，含有少量吡咯烷鎓基离子液体的电解质具有最佳性能，因为它有利于Li的迁移与咪唑鎓基阳离子相比， ⁺阳离子朝向负极。