Abstract
Single-ion conducting polymer blends (SICPBs) have demonstrated exceptional electrochemical performance as solid-state battery electrolytes; however, their nanoscale morphology and thermodynamic behavior remain unexplored. In this work, we investigate blends composed of deuterated poly(ethylene oxide) and poly[lithium sulfonyl(trifluoromethane sulfonyl)imide methacrylate], dPEO/P(LiMTFSI), and report the first experimental study of the nanostructures of charge-neutral polymer blends using small-angle neutron scattering (SANS) and small-angle X-ray scattering (SAXS). Despite the macroscopic miscibility indicated by a single glass-transition temperature, SANS and SAXS results reveal disordered, charge-correlated nanostructures that are strongly influenced by blend composition and temperature. At low concentrations of charge polymer, the scattering is dominated by concentration fluctuations, and the random phase approximation is applied to extract values of the Flory–Huggins interaction parameter, χSC. At higher charged polymer content, concentration fluctuations are suppressed, and a correlation model is used to characterize the nanostructures of the charge correlations. We find that the structures of the charge correlations are highly dependent on blend composition─consistent with predictions from Sing’s self-consistent field theory-liquid state models. Understanding these features is essential for uncovering the ion transport mechanism that leads to improved electrochemical performance previously reported in SICPB systems.
| Original language | English |
|---|---|
| Pages (from-to) | 8866-8876 |
| Number of pages | 11 |
| Journal | Macromolecules |
| Volume | 58 |
| Issue number | 16 |
| DOIs | |
| State | Published - Aug 26 2025 |
Funding
This research was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award #DE-SC0025449. The authors gratefully acknowledge the use of facilities and instrumentation at Wisconsin Centers for Nanoscale Technology (https://wcnt.wisc.edu/) partially supported by the NSF through the University of Wisconsin Materials Research Science and Engineering Center (DMR-2309000). The Bruker AVANCE III 400 NMR spectrometer was supported by NSF grant CHE-1048642. We appreciate the assistance from Prof. AJ Boydston with the differential scanning calorimetry and gel permeation chromatography. This research used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. The beam time was allocated to CG-2 (GP-SANS) on proposal number IPTS-32043-1.