Macrophase-Separated Organic Ionic Plastic Crystals/PAMPS-Based Ionomer Electrolyte: A New Design Perspective for Flexible and Highly Conductive Solid-State Electrolytes

[Image: see text] A material design approach was taken for the preparation of an organic ionic plastic crystal (OIPC)-polymer electrolyte material that exhibited both good mechanical and transport properties. Previous attempts to form this type of electrolyte material resulted in the solvation of the OIPC by the ionomer and loss of the plastic crystal component. Here, we prepared, in situ, a macrophase-separated OIPC-polymer electrolyte system by adding lithium bis(fluorosulfonyl)imide (LiFSI) to a (PAMPS–N(1222)) ionomer. It was found that an optimal compositional window of 40–50 mol % LiFSI exists whereby the electrolyte conductivity suddenly increased 4 orders of magnitude while exhibiting elastic and flexible mechanical properties. The phase behavior and transport properties were studied using differential scanning calorimetry and (7)Li and (19)F solid-state nuclear magnetic resonance spectroscopy. This is the first example of a fabrication principle that lends itself to a wide range of promising OIPC and ionomeric materials. Subsequent studies are required to characterize and understand the morphology and conductive nature of these systems and their application as electrolyte materials.