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Nuclear magnetic resonance characterization of solid polymer electrolyte materials Michan, Alison Louise
Abstract
Solid polymer electrolytes have the potential to improve manufacturability, performance, and safety characteristics of lithium-ion batteries by replacing conventional liquid electrolytes. Two different solid polymer electrolyte materials were characterized using Nuclear Magnetic Resonance (NMR) techniques. The first material is a result of research efforts on single-ion conducting polymers. The material is intended to combine the high conductivity properties of ionic liquids with lithium cation single-ion conduction. The goal of the synthesis was to produce a polymerized ionic liquid, where crosslinking an anionic monomer (AMLi) with poly(ethylene glycol) dimethacrylate (PEGDM) immobilizes the fluorinated anionic species. Pulsed-field gradient NMR diffusion measurements of the AMLi/PEGDM samples have demonstrated that both the lithium cations and fluorinated anions are mobile and contributing toward conductivity. Therefore, further work is required to successfully immobilize the fluorinated anion in a crosslinked network. The ⁷Li and ¹⁹F diffusion coefficients of the AMLi/PEGDM 40/60 sample were 3.4x10⁻⁸ cm²/s and 2.2x10⁻⁸ cm²/s at 100°C. The second material incorporates a poly(ethylene oxide) (PEO) conductive block and polyethylene (PE) reinforcement block. The PEO/PEO-b-PE/LiClO₄ samples were not intended to be single-ion conducting and materials synthesis aimed to maximize conductivity and mechanical properties. A ⁷Li diffusion coefficient of ~4x10⁻⁸ cm²/s at 60°C was observed. It is expected that the anion would also be mobile and therefore the polymer electrolyte would be a bi-ionic conductor. These samples demonstrated higher ⁷Li diffusion coefficients at a given temperature and superior mechanical properties for a flexible polymer electrolyte compared to the AMLi/PEGDM samples. Practically, the diffusion measurements of the solid polymer samples are extremely challenging, as the spin-spin (T₂) relaxation times are very short, necessitating the development of specialized pulsed-field gradient apparatus. These results provide valuable insight into the conduction mechanisms in these materials, and will drive further optimization of solid polymer electrolytes.
Item Metadata
| Title |
Nuclear magnetic resonance characterization of solid polymer electrolyte materials
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| Creator | |
| Publisher |
University of British Columbia
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| Date Issued |
2012
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| Description |
Solid polymer electrolytes have the potential to improve manufacturability, performance, and safety characteristics of lithium-ion batteries by replacing conventional liquid electrolytes. Two different solid polymer electrolyte materials were characterized using Nuclear Magnetic Resonance (NMR) techniques. The first material is a result of research efforts on single-ion conducting polymers. The material is intended to combine the high conductivity properties of ionic liquids with lithium cation single-ion conduction. The goal of the synthesis was to produce a polymerized ionic liquid, where crosslinking an anionic monomer (AMLi) with poly(ethylene glycol) dimethacrylate (PEGDM) immobilizes the fluorinated anionic species. Pulsed-field gradient NMR diffusion measurements of the AMLi/PEGDM samples have demonstrated that both the lithium cations and fluorinated anions are mobile and contributing toward conductivity. Therefore, further work is required to successfully immobilize the fluorinated anion in a crosslinked network. The ⁷Li and ¹⁹F diffusion coefficients of the AMLi/PEGDM 40/60 sample were 3.4x10⁻⁸ cm²/s and 2.2x10⁻⁸ cm²/s at 100°C. The second material incorporates a poly(ethylene oxide) (PEO) conductive block and polyethylene (PE) reinforcement block. The PEO/PEO-b-PE/LiClO₄ samples were not intended to be single-ion conducting and materials synthesis aimed to maximize conductivity and mechanical properties. A ⁷Li diffusion coefficient of ~4x10⁻⁸ cm²/s at 60°C was observed. It is expected that the anion would also be mobile and therefore the polymer electrolyte would be a bi-ionic conductor. These samples demonstrated higher ⁷Li diffusion coefficients at a given temperature and superior mechanical properties for a flexible polymer electrolyte compared to the AMLi/PEGDM samples. Practically, the diffusion measurements of the solid polymer samples are extremely challenging, as the spin-spin (T₂) relaxation times are very short, necessitating the development of specialized pulsed-field gradient apparatus. These results provide valuable insight into the conduction mechanisms in these materials, and will drive further optimization of solid polymer electrolytes.
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| Genre | |
| Type | |
| Language |
eng
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| Date Available |
2012-07-06
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| Provider |
Vancouver : University of British Columbia Library
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| Rights |
Attribution-NonCommercial-NoDerivatives 4.0 International
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| DOI |
10.14288/1.0072863
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| URI | |
| Degree | |
| Program | |
| Affiliation | |
| Degree Grantor |
University of British Columbia
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| Graduation Date |
2012-11
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| Campus | |
| Scholarly Level |
Graduate
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| Rights URI | |
| Aggregated Source Repository |
DSpace
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Attribution-NonCommercial-NoDerivatives 4.0 International