Probing Transport of Ion Dense Electrolytes using Electrophoretic NMR
Ion transport of electrolytes determines the performance of many electroactive devices, from fuel cells to batteries to soft mechanical actuators. This dissertation aims to address some fundamental issues regarding ion transport of ion dense electrolytes using electrophoretic NMR and NMR diffusometr...
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ndltd-VTETD-oai-vtechworks.lib.vt.edu-10919-519662020-09-29T05:37:55Z Probing Transport of Ion Dense Electrolytes using Electrophoretic NMR Zhang, Zhiyang Chemistry Madsen, Louis A. Moore, Robert Bowen Morris, John R. Troya, Diego transport electrophoretic NMR electrophoretic mobility conductivity Ion transport of electrolytes determines the performance of many electroactive devices, from fuel cells to batteries to soft mechanical actuators. This dissertation aims to address some fundamental issues regarding ion transport of ion dense electrolytes using electrophoretic NMR and NMR diffusometry. I first describe the design and fabrication of the first instrumentation capable of reliable ENMR on highly ion-dense electrolytes such as ionic liquids and electrolytes for zinc-air batteries. I design a new electrophoretic NMR sample cell using parallel capillaries to investigate the electrophoretic mobilities of pure ionic liquids. It shows the first study of a highly ion-dense electrolyte with electrophoretic NMR. Then I employ NMR diffusometry and electrophoretic NMR to investigate ion association of pure ionic liquids. Then I use electrophoretic NMR technique to investigate the electrophoretic mobilities of electrolytes for zinc-air batteries. For Zn2+ salt added dicyanamide (dca) based ionic liquids, I investigate the effects of Zn2+ salt on chemical shift of dca and ion motion. The combination of mobilities measurements and diffusion measurements provides some new insight of ion aggregation. We explore ion transport of ionic liquids inside the ionic polymer Nafion as a function of hydration level. When ionic liquids diffuse inside ionic polymers, isolated anions diffuse faster (e 4X) than cations at high hydration whereas ion associations result in substantially faster cation diffusion (d 3X) at low hydration inside membranes, revealing prevalent anionic aggregates. Finally, we compare diffusion activation energy measurements in a hydrated perfluorosulfonate ionomer and aqueous solutions of triflic acid, which provides insight into water transport dynamics on sub-nm lengthscales. And we explore the physical meaning of activation energy, characterizing local intermolecular interactions that occur on the pre-diffusional (~ 1 ps) timescale. Ph. D. 2015-05-03T06:00:53Z 2015-05-03T06:00:53Z 2013-11-08 Dissertation vt_gsexam:1648 http://hdl.handle.net/10919/51966 In Copyright http://rightsstatements.org/vocab/InC/1.0/ ETD application/pdf application/pdf Virginia Tech |
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transport electrophoretic NMR electrophoretic mobility conductivity |
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transport electrophoretic NMR electrophoretic mobility conductivity Zhang, Zhiyang Probing Transport of Ion Dense Electrolytes using Electrophoretic NMR |
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Ion transport of electrolytes determines the performance of many electroactive devices, from fuel cells to batteries to soft mechanical actuators. This dissertation aims to address some fundamental issues regarding ion transport of ion dense electrolytes using electrophoretic NMR and NMR diffusometry.
I first describe the design and fabrication of the first instrumentation capable of reliable ENMR on highly ion-dense electrolytes such as ionic liquids and electrolytes for zinc-air batteries. I design a new electrophoretic NMR sample cell using parallel capillaries to investigate the electrophoretic mobilities of pure ionic liquids. It shows the first study of a highly ion-dense electrolyte with electrophoretic NMR. Then I employ NMR diffusometry and electrophoretic NMR to investigate ion association of pure ionic liquids.
Then I use electrophoretic NMR technique to investigate the electrophoretic mobilities of electrolytes for zinc-air batteries. For Zn2+ salt added dicyanamide (dca) based ionic liquids, I investigate the effects of Zn2+ salt on chemical shift of dca and ion motion. The combination of mobilities measurements and diffusion measurements provides some new insight of ion aggregation.
We explore ion transport of ionic liquids inside the ionic polymer Nafion as a function of hydration level. When ionic liquids diffuse inside ionic polymers, isolated anions diffuse faster (e 4X) than cations at high hydration whereas ion associations result in substantially faster cation diffusion (d 3X) at low hydration inside membranes, revealing prevalent anionic aggregates.
Finally, we compare diffusion activation energy measurements in a hydrated perfluorosulfonate ionomer and aqueous solutions of triflic acid, which provides insight into water transport dynamics on sub-nm lengthscales. And we explore the physical meaning of activation energy, characterizing local intermolecular interactions that occur on the pre-diffusional (~ 1 ps) timescale. === Ph. D. |
author2 |
Chemistry |
author_facet |
Chemistry Zhang, Zhiyang |
author |
Zhang, Zhiyang |
author_sort |
Zhang, Zhiyang |
title |
Probing Transport of Ion Dense Electrolytes using Electrophoretic NMR |
title_short |
Probing Transport of Ion Dense Electrolytes using Electrophoretic NMR |
title_full |
Probing Transport of Ion Dense Electrolytes using Electrophoretic NMR |
title_fullStr |
Probing Transport of Ion Dense Electrolytes using Electrophoretic NMR |
title_full_unstemmed |
Probing Transport of Ion Dense Electrolytes using Electrophoretic NMR |
title_sort |
probing transport of ion dense electrolytes using electrophoretic nmr |
publisher |
Virginia Tech |
publishDate |
2015 |
url |
http://hdl.handle.net/10919/51966 |
work_keys_str_mv |
AT zhangzhiyang probingtransportofiondenseelectrolytesusingelectrophoreticnmr |
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1719344545379909632 |