Modeling ion mobility in solid-state polymer electrolytes

Abstract

We introduce a course-grained model of ion diffusion in a solid-state polymer electrolyte. Among many tunable parameters, we investigate the effect of ion concentration, ion-polymer attraction, and polymer disorder on cation diffusion. For the conditions tested, we find that ion concentration has little effect on diffusion. Polymer disorder creates local variation in behavior, which we call "trapping" (low diffusion) and "free diffusing" (high diffusion) regions. Changing ion-polymer attraction modulates the relative importance of trapping and free diffusing behavior. Using this model, we can continue to investigate how a number of factors affect cation diffusion both mechanistically and numerically, with the end goal of enabling rapid computational material design.