Morphology Effects on Ion Transport in Nanostructured Block Copolymer Electrolytes
발표자
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초록
내용
Block copolymer (BCP) electrolytes have been spotlighted for desirable ion transport properties for battery applications. Through microphase separation, the conductivity and mechanical integrity of BCPs are improved together by increasing polymer chain lengths. Previous studies attributed the local tortuosity to govern ion transport, leaving further questions on the molecular mechanisms of retarding ions at domain interfaces. In this work, we perform molecular dynamics simulations on lithium salt-doped PS-b-PEO with lamellar and hexagonal nanostructures using united-atom models. We characterize the spatial heterogeneity of ion diffusion depending on proximity to domain interfaces. The interfacial slowing is interpreted in terms of polymer segmental motions and propensity of ion hopping by local environments. By varying domain sizes, we study the effects of volume portion and curvature of the interfacial zone on ion conduction. This study envisages the morphological design rules for optimizing ion conduction in BCP electrolytes.