Takekawa Reiji, Kawamura Junichi
Institute for Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1, Katahira, Aobaku Sendai 980-8577, Japan.
Institute for Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1, Katahira, Aobaku Sendai 980-8577, Japan.
J Magn Reson. 2021 May;326:106958. doi: 10.1016/j.jmr.2021.106958. Epub 2021 Feb 24.
In this study, the restricted diffusion of a solvent, anion, and cation in an electrolyte solution was measured by pulsed field gradient (PFG) NMR for H, F, and Li nuclei. Further, the time dependences of the diffusion coefficients were measured for a 1 M LiPF electrolyte solution in porous polyethylene, which has pores with sizes of tens of micrometers. The decreasing ratio of the diffusion coefficients of the solvent, cation, and anion based on the diffusion time can be scaled similarly for each diffusion distance. The experimentally obtained time dependences of the diffusion coefficients of the solvent, anion, and cation agreed with the results of the analytical equation with the same structural parameters. Furthermore, the abovementioned experimental results were produced via Monte Carlo simulation in the same model-restricted structure for the solvent, anion, and cation. Based on PFG-NMR, it can be concluded that the solvent, anion, and cation exhibit the same restricted diffusion behavior in polyethylene pores measuring tens of micrometers. It was confirmed that measuring the time dependences of the diffusion coefficients via PFG-NMR with multiple nuclei is effective for studying the diffusion mechanisms of electrolyte solutions in restricted spaces.
在本研究中，通过脉冲场梯度（PFG）核磁共振对H、F和Li原子核测量了电解质溶液中溶剂、阴离子和阳离子的受限扩散。此外，还测量了1 M LiPF电解质溶液在具有数十微米孔径的多孔聚乙烯中的扩散系数随时间的变化。基于扩散时间，溶剂、阳离子和阴离子扩散系数的降低比率对于每个扩散距离都可以类似地进行缩放。实验获得的溶剂、阴离子和阳离子扩散系数随时间的变化与具有相同结构参数的解析方程结果一致。此外，上述实验结果是通过在溶剂、阴离子和阳离子的相同模型受限结构中进行蒙特卡罗模拟得出的。基于PFG-NMR，可以得出结论，溶剂、阴离子和阳离子在尺寸为数十微米的聚乙烯孔中表现出相同的受限扩散行为。证实了通过具有多个原子核的PFG-NMR测量扩散系数随时间的变化对于研究电解质溶液在受限空间中的扩散机制是有效的。
