电解质
离子
化学
六氟磷酸盐
锂(药物)
化学物理
盐(化学)
离子运输机
电池(电)
无机化学
分析化学(期刊)
离子液体
物理
热力学
物理化学
色谱法
电极
有机化学
医学
功率(物理)
内分泌学
催化作用
作者
Sudipa Mitra,Ranjit Biswas
摘要
Understanding microscopic directional correlations in ion movements within lithium-ion battery (LIB) electrolytes is important because these correlations directly affect the ionic conductivity. Onsager transport coefficients are widely used to understand these correlations. On the other hand, the Van Hove function (VHF) is also capable of determining correlated motions. However, identifying various types of ion correlated motions in LIB electrolytes using VHF is not well explored. Here, we have conducted molecular dynamics simulations of a representative experimental LIB electrolyte system—lithium hexafluorophosphate (LiPF6)—at different concentrations in a (9:1 wt. %) mixture of ethyl methyl carbonate and fluoroethylene carbonate in order to explore the capabilities and limitations of using VHF to understand different types of ion correlations. We conclude that analysis of VHF can qualitatively describe both the positive correlation between cation–anion at different salt concentrations and the negative correlation between cation–cation and anion–anion present in high salt concentration, but it cannot foretell which correlation is dominating at any given electrolyte concentration. This type of quantitative information can be obtained only via Onsager’s approach. This could be seen as a limitation of relying solely on VHF to fully understand ion correlation in electrolyte media.
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