Revealing the Solvation Structure and Dynamics of Carbonate Electrolytes in Lithium-Ion Batteries by Two-Dimensional Infrared Spectrum Modeling,The Journal of Physical Chemistry Letters

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Revealing the Solvation Structure and Dynamics of Carbonate Electrolytes in Lithium-Ion Batteries by Two-Dimensional Infrared Spectrum Modeling
The Journal of Physical Chemistry Letters ( IF 4.8 ) Pub Date : 2017-11-14 00:00:00 , DOI: 10.1021/acs.jpclett.7b02623
Chungwen Liang ₁ , Kyungwon Kwak _{1,

2} , Minhaeng Cho _{1,

2}

Affiliation

Carbonate electrolytes in lithium-ion batteries play a crucial role in conducting lithium ions between two electrodes. Mixed solvent electrolytes consisting of linear and cyclic carbonates are commonly used in commercial lithium-ion batteries. To understand how the linear and cyclic carbonates introduce different solvation structures and dynamics, we performed molecular dynamics simulations of two representative electrolyte systems containing either linear or cyclic carbonate solvents. We then modeled their two-dimensional infrared (2DIR) spectra of the carbonyl stretching mode of these carbonate molecules. We found that the chemical exchange process involving formation and dissociation of lithium-ion/carbonate complexes is responsible for the growth of 2DIR cross peaks with increasing waiting time. In addition, we also found that cyclic carbonates introduce faster dynamics of dissociation and formation of lithium-ion/carbonate complexes than linear carbonates. These findings provide new insights into understanding the lithium-ion mobility and its interplay with solvation structure and ultrafast dynamics in carbonate electrolytes used in lithium-ion batteries.

中文翻译：

二维红外光谱建模揭示锂离子电池中碳酸盐电解质的溶剂化结构和动力学

锂离子电池中的碳酸盐电解质在两个电极之间传导锂离子方面起着至关重要的作用。由线性和环状碳酸酯组成的混合溶剂电解质通常用于商业锂离子电池中。为了了解线性和环状碳酸酯如何引入不同的溶剂化结构和动力学，我们对包含线性或环状碳酸酯溶剂的两个代表性电解质体系进行了分子动力学模拟。然后，我们对这些碳酸盐分子的羰基拉伸模式的二维红外（2DIR）光谱进行了建模。我们发现，涉及锂离子/碳酸盐配合物形成和解离的化学交换过程是2DIR交叉峰随等待时间增加而增长的原因。此外，我们还发现，环状碳酸酯比线性碳酸酯具有更快的解离动力学和锂离子/碳酸酯络合物的形成。这些发现为了解锂离子迁移率及其与溶剂化结构的相互作用以及锂离子电池中使用的碳酸盐电解质的超快动力学提供了新的见解。

更新日期：2017-11-15

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