论文总字数：23268字

摘 要

离子液体不仅常常被用于超级电容器里的电解质，而且也作为润滑剂来减少固体表面之间的摩擦，因此需要研究界面影响下离子液体微观结构的性质。阐明碳狭缝范围内离子液体的微观结构和稳定性是了解离子液体和介孔碳电极材料之间相互作用的第一步，也是重要的一步。为了研究咪唑类离子液体受到界面影响时的微观结构的变化，本文采用分子动力学模拟的研究方法来进行相关模拟实验。观察 [BMIM][PF₆]离子液体在宽为2.8 nm碳狭缝中的行为，发现受限的离子液体形成了明显的分层现象，并且可以根据其数密度分布曲线中的谷坐标分为紧致层、亚紧致层和中心层三个区域。无论是否存在外加电场，在紧致层中，离子液体的咪唑环均存在“平行”和“倾斜站立”两个优先取向，而在亚紧致层和中心层中，离子液体的咪唑环存在“倾斜站立”的优先取向。本文通过外加电场实现了对咪唑类离子液体在狭缝内微观结构的调控，进而优化咪唑类离子液体在应用过程的性能。

关键词：咪唑类离子液体 微观结构 分子模拟 界面影响

Study on the Microstructure of Imidazolium-based Ionic Liquids on Carbon Surface

ACSTRACT

Ionic liquids are often used not only as electrolytes in supercapacitors, but also as lubricants to reduce friction between solid surfaces. Therefore, this work need to study the properties of ionic liquid microstructure under the influence of interfaces. At the same time, imidazole ionic liquids have been studied in various countries as capacitor electrolytes. Clarifying the microstructure and stability of the ionic liquid in the carbon slit range is the first and important step in understanding the interaction between ionic liquid and mesoporous carbon electrode materials. In order to study the changes in the microstructure of imidazole ionic liquids when they are affected by the interface, this work used molecular dynamics simulations to carry out related simulation experiments, and conducted two studies with or without an applied electric field. This work observed the behavior of [BMIM][PF₆] ionic liquid in a carbon slit with a width of 2.8 nm, and found that the restricted ionic liquid formed an obvious layering phenomenon, and can be divided according to the valley coordinates in its number density distribution curve There are three areas: com-layer, sub- layer and cen-layer. In the com-layer, the imidazole ring of the ionic liquid has two preferential orientations of “parallel” and “slanting standing”, while in the sub-layer and the cen-layer, the imidazole ring of the ionic liquid has a preferential orientation of “slanting standing”. In this paper, the microstructure of the imidazole ionic liquid in the slit is adjusted by applying an electric field, and then the performance of the imidazole ionic liquid in the application process is optimized.

Key Words: Imidazolium-based ionic liquid; Micro structure; Molecular simulation; Interface impact

目 录

摘要 I

ACSTRACT II

第一章 绪论 1

1.1研究背景 1

1.2分子动力学模拟 2

1.21引言 2

1.2.2模拟的基本原理 2

1.2.3热力学系综 2

1.2.4分子动力学模拟 2

1.3 研究内容及方法 3

1.3.1 研究内容 3

1.3.2 研究对象 3

1.3.3研究方法 3

1.4 研究现状 4

1.4.1电容器方面 4

1.4.2润滑剂方面 5

1.5 课题研究意义 5

第二章 分子动力学模拟方法 7

2.1 模拟构型的建立 7

2.2 力场参数 8

2.3 模拟过程 9

2.3.1无外加电场的情况 9

2.3.2有外加电场的情况 9

第三章 结果与讨论 11

3.1 无外加电场的情况 11

3.1.1离子液体沿Z轴的空间分布 11

3.1.2 [BMIM]阳离子的优先取向 12

3.2 有外加电场的情况 13

3.2.1离子液体沿Z轴的空间分布 13

3.2.2[BMIM]阳离子的优先取向 15

3.3 有无外加电场的对比 15

3.3.1离子液体沿Z轴的空间分布的对比 15

3.3.2[BMIM]阳离子的优先取向的对比 16

第四章 结论与展望 17

4.1 结论 17

4.2 展望 17

参考文献 18

致谢 21

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