Influence of Dielectric Constant on Ionic Transport in Polyether-Based Electrolytes

We use all-atom molecular dynamics simulations to study the effect of polymer polarity, as quantified by the dielectric constant, on the transport properties of lithium bis­(trifluoromethylsulfonyl)­imide (LiTFSI) doped polyethers. Our results indicate that increasing the host dielectric constant leads to a decrease in ionic cluster sizes and reduction in correlated motion of oppositely charged ions. This causes the ionic conductivity to more closely approach the Nernst-Einstein limit in which ionic conductivity is only limited by the diffusivities of Li⁺ and TFSI^–. We compare our results to recent experimental observations which demonstrate similar qualitative trends in host polarity.