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The Influence of Anion Shape on the Electrical Double Layer Microstructure and Capacitance of Ionic Liquids-Based Supercapacitors by Molecular Simulations

Room-temperature ionic liquids (RTILs) are an emerging class of electrolytes for supercapacitors. In this work, we investigate the effects of different supercapacitor models and anion shape on the electrical double layers (EDLs) of two different RTILs: 1-ethyl-3-methylimidazolium bis(trifluoromethan...

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Autores principales: Chen, Ming, Li, Song, Feng, Guang
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6155607/
https://www.ncbi.nlm.nih.gov/pubmed/28212336
http://dx.doi.org/10.3390/molecules22020241
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author Chen, Ming
Li, Song
Feng, Guang
author_facet Chen, Ming
Li, Song
Feng, Guang
author_sort Chen, Ming
collection PubMed
description Room-temperature ionic liquids (RTILs) are an emerging class of electrolytes for supercapacitors. In this work, we investigate the effects of different supercapacitor models and anion shape on the electrical double layers (EDLs) of two different RTILs: 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Emim][Tf(2)N]) and 1-ethyl-3-methylimidazolium 2-(cyano)pyrrolide ([Emim][CNPyr]) by molecular dynamics (MD) simulation. The EDL microstructure is represented by number densities of cations and anions, and the potential drop near neutral and charged electrodes reveal that the supercapacitor model with a single electrode has the same EDL structure as the model with two opposite electrodes. Nevertheless, the employment of the one-electrode model without tuning the bulk density of RTILs is more time-saving in contrast to the two-electrode one. With the one-electrode model, our simulation demonstrated that the shapes of anions significantly imposed effects on the microstructure of EDLs. The EDL differential capacitance vs. potential (C-V) curves of [Emim][CNPyr] electrolyte exhibit higher differential capacitance at positive potentials. The modeling study provides microscopic insight into the EDLs structure of RTILs with different anion shapes.
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spelling pubmed-61556072018-11-13 The Influence of Anion Shape on the Electrical Double Layer Microstructure and Capacitance of Ionic Liquids-Based Supercapacitors by Molecular Simulations Chen, Ming Li, Song Feng, Guang Molecules Article Room-temperature ionic liquids (RTILs) are an emerging class of electrolytes for supercapacitors. In this work, we investigate the effects of different supercapacitor models and anion shape on the electrical double layers (EDLs) of two different RTILs: 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Emim][Tf(2)N]) and 1-ethyl-3-methylimidazolium 2-(cyano)pyrrolide ([Emim][CNPyr]) by molecular dynamics (MD) simulation. The EDL microstructure is represented by number densities of cations and anions, and the potential drop near neutral and charged electrodes reveal that the supercapacitor model with a single electrode has the same EDL structure as the model with two opposite electrodes. Nevertheless, the employment of the one-electrode model without tuning the bulk density of RTILs is more time-saving in contrast to the two-electrode one. With the one-electrode model, our simulation demonstrated that the shapes of anions significantly imposed effects on the microstructure of EDLs. The EDL differential capacitance vs. potential (C-V) curves of [Emim][CNPyr] electrolyte exhibit higher differential capacitance at positive potentials. The modeling study provides microscopic insight into the EDLs structure of RTILs with different anion shapes. MDPI 2017-02-16 /pmc/articles/PMC6155607/ /pubmed/28212336 http://dx.doi.org/10.3390/molecules22020241 Text en © 2017 by the authors. 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 (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Chen, Ming
Li, Song
Feng, Guang
The Influence of Anion Shape on the Electrical Double Layer Microstructure and Capacitance of Ionic Liquids-Based Supercapacitors by Molecular Simulations
title The Influence of Anion Shape on the Electrical Double Layer Microstructure and Capacitance of Ionic Liquids-Based Supercapacitors by Molecular Simulations
title_full The Influence of Anion Shape on the Electrical Double Layer Microstructure and Capacitance of Ionic Liquids-Based Supercapacitors by Molecular Simulations
title_fullStr The Influence of Anion Shape on the Electrical Double Layer Microstructure and Capacitance of Ionic Liquids-Based Supercapacitors by Molecular Simulations
title_full_unstemmed The Influence of Anion Shape on the Electrical Double Layer Microstructure and Capacitance of Ionic Liquids-Based Supercapacitors by Molecular Simulations
title_short The Influence of Anion Shape on the Electrical Double Layer Microstructure and Capacitance of Ionic Liquids-Based Supercapacitors by Molecular Simulations
title_sort influence of anion shape on the electrical double layer microstructure and capacitance of ionic liquids-based supercapacitors by molecular simulations
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6155607/
https://www.ncbi.nlm.nih.gov/pubmed/28212336
http://dx.doi.org/10.3390/molecules22020241
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