(338ai) Predicting Phase Behavior of a Polymer Electrolyte Using Molecular Simulations

Polymer electrolytes are promising materials for future energy storage. They combine solid-like stability of polymers with high conductivity of ionic liquids. Commercial viability of polymer electrolytes hinges on resolving issues related to sluggish polymer dynamics and its impact on ion transport. Recent works suggest the formation of percolating ion channels in a polymer matrix can enhance the ion transport. However, the relationship between ion channel formation and polymer topology is not well understood. Here we conduct large-scale molecular simulations to screen the polymer conformational space of a phenomenological model system and identify a wide range of nano/microstructure formations in a polymer matrix. We propose a new phase diagram for polymer electrolyte and show different phases of polymer electrolytes as a function of ion pair size, polymer’s radius of gyration and dielectric constant of the material. Further, we study the ion solvation and its connection to conductivity in a polymer matrix and identify polymer topology that can facilitate high ion conduction while maintaining good mechanical properties. Our works will have implications in next generation solid state electrolyte design.