跳或不跳:通过分子动力学模拟揭示固体聚合物电解质中离子运输的不同模式
Harish Gudla1, Anne Hockmann2, Daniel Brandell1
1Department of Chemistry - Ångström Laboratory, Uppsala University, Box 538, SE-751 21 Uppsala, Sweden.
概括
分子动力学模拟显示,连续的离子运动,而不是离子跳跃,主导着固体聚合物电解质的运输. 离子运输从聚合物中介转移到具有较高盐度的离子中介.
科学领域:
- 材料科学 材料科学 材料科学
- 电化学 电化学 电化学
- 计算化学计算化学
背景情况:
- 固体聚合物电解质 (SPEs) 中的基本离子运输模式已知,但它们的分布和影响因素仍然不清楚.
- 了解离子-聚合物和离子-离子相互作用对于优化SPE性能至关重要.
研究的目的:
- 调查基于聚乙烯氧化物和聚乙烯烯酸的SPE中的离子运输机制.
- 阐明分子量和盐度对离子运输动态的影响.
- 澄清SPEs中不同离子传输机制和相互作用的作用.
主要方法:
- 利用分子动力学模拟来研究离子运输.
- 分析了协调变化,以确定运输机制.
- 在不同分子量和LiTFSI度下研究的聚乙烯氧化物和聚乙烯α-烯酸盐.
主要成果:
- 确定了三种离子运输机制:离子跳跃,连续运动和车载运输.
- 连续运动是所有研究条件中占主导地位的机制.
- 运输从聚合物介导转向阳离子介导,盐度增加.
- 发现这些系统基本上没有离子跳跃.
- 聚合物介导的车辆运输不是一个重要的贡献者.
结论:
- 在SPEs中普遍描述的离子运输仅仅与细分运动相结合是一种过度简化.
- 常见的"离子跳跃"概念通常是不准确的描述在SPEs的阳离子运输.
- 离子运输机制复杂,并受到盐度和聚合物结构的重大影响.
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