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Influence of Particle Size Distribution on the Performance of Ionic Liquid-based Electrochemical Double Layer Capacitors

Electrochemical double layer capacitors (EDLCs) employing ionic liquid electrolytes are the subject of much research as they promise increased operating potentials, and hence energy densities, when compared with currently available devices. Herein we report on the influence of the particle size dist...

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Autores principales: Rennie, Anthony J. R., Martins, Vitor L., Smith, Rachel M., Hall, Peter J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4766507/
https://www.ncbi.nlm.nih.gov/pubmed/26911531
http://dx.doi.org/10.1038/srep22062
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author Rennie, Anthony J. R.
Martins, Vitor L.
Smith, Rachel M.
Hall, Peter J.
author_facet Rennie, Anthony J. R.
Martins, Vitor L.
Smith, Rachel M.
Hall, Peter J.
author_sort Rennie, Anthony J. R.
collection PubMed
description Electrochemical double layer capacitors (EDLCs) employing ionic liquid electrolytes are the subject of much research as they promise increased operating potentials, and hence energy densities, when compared with currently available devices. Herein we report on the influence of the particle size distribution of activated carbon material on the performance of ionic liquid based EDLCs. Mesoporous activated carbon was ball-milled for increasing durations and the resultant powders characterized physically (using laser diffraction, nitrogen sorption and SEM) and investigated electrochemically in the form of composite EDLC electrodes. A bi-modal particle size distribution was found for all materials demonstrating an increasing fraction of smaller particles with increased milling duration. In general, cell capacitance decreased with increased milling duration over a wide range of rates using CV and galvanostatic cycling. Reduced coulombic efficiency is observed at low rates (<25 mVs(−1)) and the efficiency decreases as the volume fraction of the smaller particles increases. Efficiency loss was attributed to side reactions, particularly electrolyte decomposition, arising from interactions with the smaller particles. The effect of reduced efficiency is confirmed by cycling for over 15,000 cycles, which has the important implication that diminished performance and reduced cycle life is caused by the presence of submicron-sized particles.
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spelling pubmed-47665072016-03-02 Influence of Particle Size Distribution on the Performance of Ionic Liquid-based Electrochemical Double Layer Capacitors Rennie, Anthony J. R. Martins, Vitor L. Smith, Rachel M. Hall, Peter J. Sci Rep Article Electrochemical double layer capacitors (EDLCs) employing ionic liquid electrolytes are the subject of much research as they promise increased operating potentials, and hence energy densities, when compared with currently available devices. Herein we report on the influence of the particle size distribution of activated carbon material on the performance of ionic liquid based EDLCs. Mesoporous activated carbon was ball-milled for increasing durations and the resultant powders characterized physically (using laser diffraction, nitrogen sorption and SEM) and investigated electrochemically in the form of composite EDLC electrodes. A bi-modal particle size distribution was found for all materials demonstrating an increasing fraction of smaller particles with increased milling duration. In general, cell capacitance decreased with increased milling duration over a wide range of rates using CV and galvanostatic cycling. Reduced coulombic efficiency is observed at low rates (<25 mVs(−1)) and the efficiency decreases as the volume fraction of the smaller particles increases. Efficiency loss was attributed to side reactions, particularly electrolyte decomposition, arising from interactions with the smaller particles. The effect of reduced efficiency is confirmed by cycling for over 15,000 cycles, which has the important implication that diminished performance and reduced cycle life is caused by the presence of submicron-sized particles. Nature Publishing Group 2016-02-25 /pmc/articles/PMC4766507/ /pubmed/26911531 http://dx.doi.org/10.1038/srep22062 Text en Copyright © 2016, Macmillan Publishers Limited http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
spellingShingle Article
Rennie, Anthony J. R.
Martins, Vitor L.
Smith, Rachel M.
Hall, Peter J.
Influence of Particle Size Distribution on the Performance of Ionic Liquid-based Electrochemical Double Layer Capacitors
title Influence of Particle Size Distribution on the Performance of Ionic Liquid-based Electrochemical Double Layer Capacitors
title_full Influence of Particle Size Distribution on the Performance of Ionic Liquid-based Electrochemical Double Layer Capacitors
title_fullStr Influence of Particle Size Distribution on the Performance of Ionic Liquid-based Electrochemical Double Layer Capacitors
title_full_unstemmed Influence of Particle Size Distribution on the Performance of Ionic Liquid-based Electrochemical Double Layer Capacitors
title_short Influence of Particle Size Distribution on the Performance of Ionic Liquid-based Electrochemical Double Layer Capacitors
title_sort influence of particle size distribution on the performance of ionic liquid-based electrochemical double layer capacitors
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4766507/
https://www.ncbi.nlm.nih.gov/pubmed/26911531
http://dx.doi.org/10.1038/srep22062
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