Differential capacitance of ionic liquids according to lattice-gas mean-field model with nearest-neighbor interactions
Autor(a) principal: | |
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Data de Publicação: | 2018 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UNESP |
Texto Completo: | http://dx.doi.org/10.1063/1.5047490 http://hdl.handle.net/11449/187128 |
Resumo: | The Bragg-Williams free energy is used to incorporate nearest-neighbor interactions into the lattice gas model of a solvent-free ionic liquid near a planar electrode. We calculate the differential capacitance from solutions of the mean-field consistency relation, arriving at an explicit expression in the limit of a weakly charged electrode. The two additional material parameters that appear in the theory - the degree of nonideality and the resistance to concentration changes of each ion type - give rise to different regimes that we identify and discuss. As the nonideality parameter, which becomes more positive for stronger nearest-neighbor attraction between like-charged ions, increases and the electrode is weakly charged, the differential capacitance is predicted to transition through a divergence and subsequently adopt negative values just before the ionic liquid becomes structurally unstable. This is associated with the spontaneous charging of an electrode at vanishing potential. The physical origin of the divergence and the negative sign of the differential capacitance is a nonmonotonic relationship between the surface potential and surface charge density, which reflects the formation of layered domains alternatingly enriched in counterions and coions near the electrode. The decay length of this layered domain pattern, which can be many times larger than the ion size, is reminiscent of the recently introduced concept of underscreening. |
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Repositório Institucional da UNESP |
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Differential capacitance of ionic liquids according to lattice-gas mean-field model with nearest-neighbor interactionsThe Bragg-Williams free energy is used to incorporate nearest-neighbor interactions into the lattice gas model of a solvent-free ionic liquid near a planar electrode. We calculate the differential capacitance from solutions of the mean-field consistency relation, arriving at an explicit expression in the limit of a weakly charged electrode. The two additional material parameters that appear in the theory - the degree of nonideality and the resistance to concentration changes of each ion type - give rise to different regimes that we identify and discuss. As the nonideality parameter, which becomes more positive for stronger nearest-neighbor attraction between like-charged ions, increases and the electrode is weakly charged, the differential capacitance is predicted to transition through a divergence and subsequently adopt negative values just before the ionic liquid becomes structurally unstable. This is associated with the spontaneous charging of an electrode at vanishing potential. The physical origin of the divergence and the negative sign of the differential capacitance is a nonmonotonic relationship between the surface potential and surface charge density, which reflects the formation of layered domains alternatingly enriched in counterions and coions near the electrode. The decay length of this layered domain pattern, which can be many times larger than the ion size, is reminiscent of the recently introduced concept of underscreening.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Department of Physics North Dakota State UniversityDepartment of Mathematics North Dakota State UniversityDepartment of Physics Institute of Biosciences Humanities and Exact Sciences São Paulo State University (UNESP)Department of Physics Institute of Biosciences Humanities and Exact Sciences São Paulo State University (UNESP)FAPESP: 2017/21772-2North Dakota State UniversityUniversidade Estadual Paulista (Unesp)Downing, RachelBerntson, Bjorn K.Bossa, Guilherme V. [UNESP]May, Sylvio2019-10-06T15:26:21Z2019-10-06T15:26:21Z2018-11-28info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://dx.doi.org/10.1063/1.5047490Journal of Chemical Physics, v. 149, n. 20, 2018.0021-9606http://hdl.handle.net/11449/18712810.1063/1.50474902-s2.0-85057613783Scopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengJournal of Chemical Physicsinfo:eu-repo/semantics/openAccess2021-10-23T19:23:44Zoai:repositorio.unesp.br:11449/187128Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462024-08-05T18:40:06.993557Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false |
dc.title.none.fl_str_mv |
Differential capacitance of ionic liquids according to lattice-gas mean-field model with nearest-neighbor interactions |
title |
Differential capacitance of ionic liquids according to lattice-gas mean-field model with nearest-neighbor interactions |
spellingShingle |
Differential capacitance of ionic liquids according to lattice-gas mean-field model with nearest-neighbor interactions Downing, Rachel |
title_short |
Differential capacitance of ionic liquids according to lattice-gas mean-field model with nearest-neighbor interactions |
title_full |
Differential capacitance of ionic liquids according to lattice-gas mean-field model with nearest-neighbor interactions |
title_fullStr |
Differential capacitance of ionic liquids according to lattice-gas mean-field model with nearest-neighbor interactions |
title_full_unstemmed |
Differential capacitance of ionic liquids according to lattice-gas mean-field model with nearest-neighbor interactions |
title_sort |
Differential capacitance of ionic liquids according to lattice-gas mean-field model with nearest-neighbor interactions |
author |
Downing, Rachel |
author_facet |
Downing, Rachel Berntson, Bjorn K. Bossa, Guilherme V. [UNESP] May, Sylvio |
author_role |
author |
author2 |
Berntson, Bjorn K. Bossa, Guilherme V. [UNESP] May, Sylvio |
author2_role |
author author author |
dc.contributor.none.fl_str_mv |
North Dakota State University Universidade Estadual Paulista (Unesp) |
dc.contributor.author.fl_str_mv |
Downing, Rachel Berntson, Bjorn K. Bossa, Guilherme V. [UNESP] May, Sylvio |
description |
The Bragg-Williams free energy is used to incorporate nearest-neighbor interactions into the lattice gas model of a solvent-free ionic liquid near a planar electrode. We calculate the differential capacitance from solutions of the mean-field consistency relation, arriving at an explicit expression in the limit of a weakly charged electrode. The two additional material parameters that appear in the theory - the degree of nonideality and the resistance to concentration changes of each ion type - give rise to different regimes that we identify and discuss. As the nonideality parameter, which becomes more positive for stronger nearest-neighbor attraction between like-charged ions, increases and the electrode is weakly charged, the differential capacitance is predicted to transition through a divergence and subsequently adopt negative values just before the ionic liquid becomes structurally unstable. This is associated with the spontaneous charging of an electrode at vanishing potential. The physical origin of the divergence and the negative sign of the differential capacitance is a nonmonotonic relationship between the surface potential and surface charge density, which reflects the formation of layered domains alternatingly enriched in counterions and coions near the electrode. The decay length of this layered domain pattern, which can be many times larger than the ion size, is reminiscent of the recently introduced concept of underscreening. |
publishDate |
2018 |
dc.date.none.fl_str_mv |
2018-11-28 2019-10-06T15:26:21Z 2019-10-06T15:26:21Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://dx.doi.org/10.1063/1.5047490 Journal of Chemical Physics, v. 149, n. 20, 2018. 0021-9606 http://hdl.handle.net/11449/187128 10.1063/1.5047490 2-s2.0-85057613783 |
url |
http://dx.doi.org/10.1063/1.5047490 http://hdl.handle.net/11449/187128 |
identifier_str_mv |
Journal of Chemical Physics, v. 149, n. 20, 2018. 0021-9606 10.1063/1.5047490 2-s2.0-85057613783 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Journal of Chemical Physics |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.source.none.fl_str_mv |
Scopus reponame:Repositório Institucional da UNESP instname:Universidade Estadual Paulista (UNESP) instacron:UNESP |
instname_str |
Universidade Estadual Paulista (UNESP) |
instacron_str |
UNESP |
institution |
UNESP |
reponame_str |
Repositório Institucional da UNESP |
collection |
Repositório Institucional da UNESP |
repository.name.fl_str_mv |
Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP) |
repository.mail.fl_str_mv |
|
_version_ |
1808128964687822848 |