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The Structure of the Electric Double Layer of the Protic Ionic Liquid [Dema][TfO] Analyzed by Atomic Force Spectroscopy

Protic ionic liquids are promising electrolytes for fuel cell applications. They would allow for an increase in operation temperatures to more than 100 °C, facilitating water and heat management and, thus, increasing overall efficiency. As ionic liquids consist of bulky charged molecules, the struct...

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Autores principales: Rodenbücher, Christian, Chen, Yingzhen, Wippermann, Klaus, Kowalski, Piotr M., Giesen, Margret, Mayer, Dirk, Hausen, Florian, Korte, Carsten
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8658030/
https://www.ncbi.nlm.nih.gov/pubmed/34884462
http://dx.doi.org/10.3390/ijms222312653
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author Rodenbücher, Christian
Chen, Yingzhen
Wippermann, Klaus
Kowalski, Piotr M.
Giesen, Margret
Mayer, Dirk
Hausen, Florian
Korte, Carsten
author_facet Rodenbücher, Christian
Chen, Yingzhen
Wippermann, Klaus
Kowalski, Piotr M.
Giesen, Margret
Mayer, Dirk
Hausen, Florian
Korte, Carsten
author_sort Rodenbücher, Christian
collection PubMed
description Protic ionic liquids are promising electrolytes for fuel cell applications. They would allow for an increase in operation temperatures to more than 100 °C, facilitating water and heat management and, thus, increasing overall efficiency. As ionic liquids consist of bulky charged molecules, the structure of the electric double layer significantly differs from that of aqueous electrolytes. In order to elucidate the nanoscale structure of the electrolyte–electrode interface, we employ atomic force spectroscopy, in conjunction with theoretical modeling using molecular dynamics. Investigations of the low-acidic protic ionic liquid diethylmethylammonium triflate, in contact with a platinum (100) single crystal, reveal a layered structure consisting of alternating anion and cation layers at the interface, as already described for aprotic ionic liquids. The structured double layer depends on the applied electrode potential and extends several nanometers into the liquid, whereby the stiffness decreases with increasing distance from the interface. The presence of water distorts the layering, which, in turn, significantly changes the system’s electrochemical performance. Our results indicate that for low-acidic ionic liquids, a careful adjustment of the water content is needed in order to enhance the proton transport to and from the catalytic electrode.
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spelling pubmed-86580302021-12-10 The Structure of the Electric Double Layer of the Protic Ionic Liquid [Dema][TfO] Analyzed by Atomic Force Spectroscopy Rodenbücher, Christian Chen, Yingzhen Wippermann, Klaus Kowalski, Piotr M. Giesen, Margret Mayer, Dirk Hausen, Florian Korte, Carsten Int J Mol Sci Article Protic ionic liquids are promising electrolytes for fuel cell applications. They would allow for an increase in operation temperatures to more than 100 °C, facilitating water and heat management and, thus, increasing overall efficiency. As ionic liquids consist of bulky charged molecules, the structure of the electric double layer significantly differs from that of aqueous electrolytes. In order to elucidate the nanoscale structure of the electrolyte–electrode interface, we employ atomic force spectroscopy, in conjunction with theoretical modeling using molecular dynamics. Investigations of the low-acidic protic ionic liquid diethylmethylammonium triflate, in contact with a platinum (100) single crystal, reveal a layered structure consisting of alternating anion and cation layers at the interface, as already described for aprotic ionic liquids. The structured double layer depends on the applied electrode potential and extends several nanometers into the liquid, whereby the stiffness decreases with increasing distance from the interface. The presence of water distorts the layering, which, in turn, significantly changes the system’s electrochemical performance. Our results indicate that for low-acidic ionic liquids, a careful adjustment of the water content is needed in order to enhance the proton transport to and from the catalytic electrode. MDPI 2021-11-23 /pmc/articles/PMC8658030/ /pubmed/34884462 http://dx.doi.org/10.3390/ijms222312653 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Rodenbücher, Christian
Chen, Yingzhen
Wippermann, Klaus
Kowalski, Piotr M.
Giesen, Margret
Mayer, Dirk
Hausen, Florian
Korte, Carsten
The Structure of the Electric Double Layer of the Protic Ionic Liquid [Dema][TfO] Analyzed by Atomic Force Spectroscopy
title The Structure of the Electric Double Layer of the Protic Ionic Liquid [Dema][TfO] Analyzed by Atomic Force Spectroscopy
title_full The Structure of the Electric Double Layer of the Protic Ionic Liquid [Dema][TfO] Analyzed by Atomic Force Spectroscopy
title_fullStr The Structure of the Electric Double Layer of the Protic Ionic Liquid [Dema][TfO] Analyzed by Atomic Force Spectroscopy
title_full_unstemmed The Structure of the Electric Double Layer of the Protic Ionic Liquid [Dema][TfO] Analyzed by Atomic Force Spectroscopy
title_short The Structure of the Electric Double Layer of the Protic Ionic Liquid [Dema][TfO] Analyzed by Atomic Force Spectroscopy
title_sort structure of the electric double layer of the protic ionic liquid [dema][tfo] analyzed by atomic force spectroscopy
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8658030/
https://www.ncbi.nlm.nih.gov/pubmed/34884462
http://dx.doi.org/10.3390/ijms222312653
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