Role of solvation site segmental dynamics on ion transport in ethylene-oxide based side-chain polymer electrolytes
Journal Article
·
· Journal of Materials Chemistry. A
- Univ. of Chicago, IL (United States)
- Hebrew Univ. of Jerusalem (Israel). Inst. of Chemistry
- Princeton Univ., NJ (United States)
- Univ. of Chicago, IL (United States); Argonne National Lab. (ANL), Lemont, IL (United States)
Ion conducting capability is often imparted to polymeric materials through short polyether side-chains, and yet the impact of this graft polymer architecture on ion solvation and conduction has not been fully explored. Here, we use a combination of impedance spectroscopy, vibrational spectroscopy, and atomistic molecular dynamics (MD) to compare the conductivity, ionic interactions, and polymer dynamics in a series of graft polyether electrolytes. We find that in poly[(oligo ethylene oxide)methyl ether methacrylate] (POEM), a widely used graft polymer electrolyte, the ionic conductivity drops more than an order of magnitude as the side-chain length is decreased from nine ethylene oxide (EO) units to three. This difference in conductivity is unexplained by differences in the calorimetric glass transition temperature (Tg), which varies only slightly with side-chain length. Furthermore, through vibrational spectroscopy and MD simulations we demonstrate that both linear and graft polyethers solvate Li⁺ ions effectively and dissociate them from large counterions, irrespective of side-chain length. Li⁺ ions do, however, show preferential solvation by EO units far from the methacrylate backbone. Similarly, EO units far from the backbone show enhanced segmental dynamics, while those near the immobile methacrylate group move substantially more slowly, as quantified by bond vector autocorrelation relaxation times. This heterogeneity in both ion solvation and local segmental relaxation explains variation in ion conductivity where material-averaged properties such as Tg and number of free ions fail to do so. Importantly, the ionic conductivity is dictated primarily by the segmental mobility of the EO units which form effective solvation sites, rather than system-wide dynamics.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1821196
- Alternate ID(s):
- OSTI ID: 1776386
- Journal Information:
- Journal of Materials Chemistry. A, Journal Name: Journal of Materials Chemistry. A Journal Issue: 15 Vol. 9; ISSN 2050-7488
- Publisher:
- Royal Society of ChemistryCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Role of Molecular Architecture on Ion Transport in Ethylene oxide-Based Polymer Electrolytes
Relaxation Dynamics and Ion Conduction of Poly(Ethylene Carbonate/Ethylene Oxide) Copolymer-Based Electrolytes
Improved Single-Ion Conductivity of Polymer Electrolyte via Accelerated Segmental Dynamics
Journal Article
·
Sun Feb 21 19:00:00 EST 2021
· Macromolecules
·
OSTI ID:1840587
Relaxation Dynamics and Ion Conduction of Poly(Ethylene Carbonate/Ethylene Oxide) Copolymer-Based Electrolytes
Journal Article
·
Mon Nov 28 19:00:00 EST 2022
· Journal of Physical Chemistry. C
·
OSTI ID:1906617
Improved Single-Ion Conductivity of Polymer Electrolyte via Accelerated Segmental Dynamics
Journal Article
·
Sun Dec 06 19:00:00 EST 2020
· ACS Applied Energy Materials
·
OSTI ID:1735446