当地环境对固体电解质间相中的无机元件的传输的影响
Taiping Hu1,2, Jianxin Tian3, Fuzhi Dai2,4
1School of Materials Science and Engineering, Peking University, Beijing 100871, People's Republic of China.
Journal of the American Chemical Society
|December 28, 2022
概括
对于离子电池的无形固体电解质介面层 (SEI) 的设计进行了讨论. 这项研究显示,由于四面体的形成,无形LiF阻碍了离子的传输,而Li2CO3则抑制了这一点,从而提高了电池的性能.
科学领域:
- 材料科学
- 电化学
- 计算化学
背景情况:
- 固体电解质介面 (SEI) 对于离子电池的性能和寿命至关重要.
- 了解SEI组件中的离子传输机制 (如Li2CO3和LiF) 是必不可少的,但仍然不清楚.
- 无形结构在SEI中增强Lion扩散性的作用是持续辩论的主题.
研究的目的:
- 研究无形LiF和Li2CO3中的离子扩散机制.
- 确定无形环境是否可以改善SEI组件中的离子扩散性.
- 阐明SEI构成对运输的影响.
主要方法:
- 使用机器学习潜在辅助分子动力学 (MD) 模拟.
- 模拟集中在无形LiF和Li2CO3中的离子扩散在各种温度下.
- 分析包括离子扩散率计算和结构特征.
主要成果:
- 从高温数据的Arrhenius推断显著低估了室温无形LiF中的离子扩散率.
- 在低温 (<500 K) 上形成 Li-F 正规四面体,大大降低了 LiF 中的 Li 离子扩散性.
- 在与LiF混合时,Li2CO3在防止Li-F四面体的形成方面发挥着至关重要的作用,从而增强了离子的运输.
结论:
- 由于低温四面体的形成,设计基于无形散装LiF的SEI不太可能改善离子运输.
- 2CO3的存在对于减轻结构对离子扩散的影响至关重要.
- 抑制大尺寸散相LiF的形成是提高离子电池性能的一个关键策略.
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