离子动力学在高度缩的电解质中的分子水平起源
Keisuke Shigenobu1, Seiji Tsuzuki2, Frederik Philippi2
1Research Institute for Interdisciplinary Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama 700-8530, Japan.
The journal of physical chemistry. B
|November 28, 2023
概括
了解液态电解质中的离子动态对于快充电池至关重要. 这项研究揭示了溶剂特性如何影响离子传输机制,指导设计更好的单离子导电电解质.
科学领域:
- 电化学 电化学 电化学
- 材料科学 材料科学 材料科学
- 计算化学的计算化学
背景情况:
- 单离子导电液体电解质对于高性能二次电池至关重要,能够快速充电和放电.
- 了解宏观离子运输特性与微观离子动态之间的关系至关重要,但仍然不清楚.
- 当前理论经常讨论离子转移数在缩溶液框架内,缺乏详细的微观洞察力.
研究的目的:
- 阐明微观离子动力学与高度电解质中的宏观转移数之间的联系.
- 研究溶剂性质,特别是子数,对离子结构和导电通路的影响.
- 确定与溶剂特性相关的控制离子输送机制 (交换与载体) 的关键因素.
主要方法:
- 利用分子动力学模拟来直接探测缩电解质中的微观离子行为.
- 检查的电解质用不同供体数的各种溶剂和二 (fluorosulfonyl) 胺盐制备.
- 分析了离子结构,导电路径,并引入了tLi-solventlife/tdipolerelax比,以描述离子动态.
主要成果:
- 在乙烯碳酸盐 (低DN) 电解质中观察到有利的 Li+ 结构和连续导电路.
- 随着供体数量的增加,结构和导电的减少,如在二甲基硫氧化物 (高DN) 电解质中所见.
- 确定了两个主要的离子运输机制:在低DN中占主导地位的交换 (比率<1) 和在高DN中占主导地位的载体 (比率≥1).
结论:
- 溶剂供体数量显著影响液体电解质中的Li+结构和导电路.
- -溶剂寿命/-二极体放松比率有效地区分了交换和车辆运输机制.
- 这些发现为合理的溶剂和盐的选择提供了基础,以设计高级单离子导电解质,用于先进的电池.
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