Single-ion conducting polymer electrolytes (SICPEs) present an opportunity to improve the safety and performance of batteries or other electrochemical devices, but achieving high conductivity is still a significant challenge, due to the coupling of ion transport with polymer segmental dynamics. This work focuses on correlating nanoscale morphology with ion and polymer dynamics in single-cation conducting polymers, in particular blend SICPEs, which leverage the ion transport of a mobile solvating polymer with the safety and stability of the SICPE. By blending SICPEs with a low molecular weight polymer, nanoscale ionic aggregates may be swollen with the solvating polymer, which facilitates the rapid transport of cations. In this work, traditional hard X-ray scattering is used to highlight how the SICPE blends form solvated nanochannels, while resonant tender X-ray scattering and X-ray absorption spectroscopy at the sulfur K-edge are used to further elucidate the local structure of the ionic groups. Broadband dielectric spectroscopy studies demonstrate how these solvated nanochannels may lead to the mechanism of superionic transport, in which ion motion is faster than the polymer segmental dynamics. The impact of SIC polymer backbone (poly(methyl methacrylate) vs. polystyrene) functionalized with a TFSI anion is investigated for different mobile cations, with a low MW polyethylene oxide as the solvating polymer. This work will aid in the development of design rules for achieving superionic transport in SICPE blends.
