Role of Zwitterion Addition on Ion Conduction in Polymer Electrolytes

The room temperature conductivity for polymeric single-ion conductors is stifled by the limited number density of simultaneously moving ions and their mobility. The latter depends on glass transition temperature (T_g) while the former depends on dielectric constant. We find that addition of zwitterions to a model single-ion conducting polymer significantly increased the dielectric constant and slightly increased T_g. Consequently, ionic conductivity increased despite the increase of T_g. The presented work highlights the significance of dielectric constant for ion conduction in polymeric materials and suggests that if both high dielectric constant and low T_g can be simultaneously achieved, useful single-ion conducting polymers might be realized.