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Updated: Jun 13, 2026
05:33
Solid-state Graft Copolymer Electrolytes for Lithium Battery Applications
Published on: August 12, 2013
Foreign-ion and self-ion diffusion in a crosslinked salt-in-polyether electrolyte.
J Fögeling1, M Kunze, M Schönhoff
1Institut für Materialphysik and Sonderforschungsbereich 458, University of Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany.
Physical Chemistry Chemical Physics : PCCP
|May 19, 2010
Summary
Ionic transport in polymer electrolytes like PolyG(30)LiPF(6) was studied. Findings reveal ion pair formation significantly impacts ion mobility, with two models explaining the data.
Area of Science:
- Materials Science
- Electrochemistry
- Polymer Science
Background:
- Polymer electrolytes are crucial for advanced battery technologies.
- Understanding ionic transport mechanisms in poly(ethylene oxide)-poly(propylene oxide) copolymers complexed with lithium hexafluorophosphate (LiPF6) is essential for optimizing performance.
- The influence of ion pairing on conductivity requires detailed investigation.
Purpose of the Study:
- To comprehensively study ionic transport in crosslinked poly(ethylene oxide)-poly(propylene oxide) random copolymer (PolyG(30)LiPF(6)) complexed with LiPF(6).
- To compare self-diffusion coefficients with charge diffusivity and evaluate foreign ion diffusion.
- To develop and apply a detailed ion transport model incorporating single ions and ion pairs.
Main Methods:
- Pulsed field gradient nuclear magnetic resonance (PFG-NMR) to measure self-diffusion coefficients of Li-7 and F-19.
- Impedance spectroscopy to obtain ion conductivity and derive charge diffusivity via the Nernst-Einstein equation.
- Radiotracer diffusion studies using Na-22 and I-125 to investigate foreign cation and anion diffusion.
Main Results:
- Self-diffusion coefficients of Li+ and PF6- were measured and compared with charge diffusivity.
- Diffusion of Na+ and I- in the polymer electrolyte was quantified.
- A comprehensive ion transport model, accounting for single ions and ion pairs, successfully fitted all experimental data.
- Two model variants, differing in ion pair fraction and mobility, equally explained the observed ionic transport behavior.
Conclusions:
- Ion pair formation plays a significant role in the ionic transport of PolyG(30)LiPF(6).
- The study provides insights into two possible mechanisms for ion pair contribution to migration: a small fraction of highly mobile pairs or a large fraction of less mobile pairs.
- The findings contribute to a deeper understanding of ion transport in polymer electrolytes, aiding in the design of improved solid-state batteries.
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