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Effects of Solvent Polarity on Li-ion Diffusion in Polymer Electrolytes: An All-Atom Molecular Dynamics Study with Charge Scaling.

ABSTRACT: We herein report an all-atom molecular dynamics study on the role of solvent polarity for Li+ diffusion in polymer electrolytes using PEO-LiTFSI (poly(ethylene oxide)-lithium bis(trifluoromethane)sulfonimide) as a model system. By separating the effect of Tg and the effect of solvent polarity in our simulations, we show that the maximum in the diffusion coefficient of Li+ with respect to the dielectric constant of polymer solvent ?p is due to transitions in the transport mechanism. In particular, it is found that the frequent interchain hopping involves the coordination of both PEO and TFSI. This optimal solvating ability of PEO at an intermediate value of ?p leads to the fast ion conduction. These findings highlight the synergetic effect of solvent polarity and bond polarity on Li-ion diffusion in solid polymer electrolytes.

SUBMITTER: Gudla H

PROVIDER: S-EPMC7503542 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature

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Effects of Solvent Polarity on Li-ion Diffusion in Polymer Electrolytes: An All-Atom Molecular Dynamics Study with Charge Scaling.

Gudla Harish H Zhang Chao C Brandell Daniel D

The journal of physical chemistry. B 20200904 37

We herein report an all-atom molecular dynamics study on the role of solvent polarity for Li+ diffusion in polymer electrolytes using PEO-LiTFSI (poly(ethylene oxide)-lithium bis(trifluoromethane)sulfonimide) as a model system. By separating the effect of Tg and the effect of solvent polarity in our simulations, we show that the maximum in the diffusion coefficient of Li+ with respect to the dielectric constant of polymer solvent εp is due to tr ...[more]

PMID: 32840375

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