Mabuchi Takuya, Nakajima Koki, Tokumasu Takashi
Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 2-1-1 Katahira Aoba-ku, Sendai 980-8577, Miyagi, Japan.
Institute of Fluid Science, Tohoku University, 2-1-1 Katahira Aoba-ku, Sendai 980-8577, Miyagi, Japan.
Micromachines (Basel). 2021 Aug 26;12(9):1012. doi: 10.3390/mi12091012.
Atomistic analysis of the ion transport in polymer electrolytes for all-solid-state Li-ion batteries was performed using molecular dynamics simulations to investigate the relationship between Li-ion transport and polymer morphology. Polyethylene oxide (PEO) and poly(diethylene oxide-alt-oxymethylene), P(2EO-MO), were used as the electrolyte materials, and the effects of salt concentrations and polymer types on the ion transport properties were explored. The size and number of LiTFSI clusters were found to increase with increasing salt concentrations, leading to a decrease in ion diffusivity at high salt concentrations. The Li-ion transport mechanisms were further analyzed by calculating the inter/intra-hopping rate and distance at various ion concentrations in PEO and P(2EO-MO) polymers. While the balance between the rate and distance of inter-hopping was comparable for both PEO and P(2EO-MO), the intra-hopping rate and distance were found to be higher in PEO than in P(2EO-MO), leading to a higher diffusivity in PEO. The results of this study provide insights into the correlation between the nanoscopic structures of ion solvation and the dynamics of Li-ion transport in polymer electrolytes.
使用分子动力学模拟对全固态锂离子电池聚合物电解质中的离子传输进行了原子分析，以研究锂离子传输与聚合物形态之间的关系。聚环氧乙烷（PEO）和聚（二环氧乙烷-alt-氧亚甲基），即P(2EO-MO)，被用作电解质材料，并探讨了盐浓度和聚合物类型对离子传输性能的影响。发现LiTFSI簇的尺寸和数量随着盐浓度的增加而增加，导致高盐浓度下离子扩散率降低。通过计算PEO和P(2EO-MO)聚合物中不同离子浓度下的跨/内跳跃速率和距离，进一步分析了锂离子传输机制。虽然PEO和P(2EO-MO)的跨跳跃速率和距离之间的平衡相当，但发现PEO中的内跳跃速率和距离高于P(2EO-MO)，导致PEO中具有更高的扩散率。本研究结果为离子溶剂化的纳米结构与聚合物电解质中锂离子传输动力学之间的相关性提供了见解。
