Electrolyte cation length influences electrosorption and dynamics in porous carbon supercapacitors

Boris Dyatkin; Naresh C. Osti; Alejandro Gallegos; Yu Zhang; Eugene Mamontov; Peter T. Cummings; Jianzhong Wu; Yury Gogotsi

doi:10.1016/j.electacta.2018.06.200

Electrolyte cation length influences electrosorption and dynamics in porous carbon supercapacitors

Boris Dyatkin, Naresh C. Osti, Alejandro Gallegos, Yu Zhang, Eugene Mamontov, Peter T. Cummings, Jianzhong Wu, Yury Gogotsi

Chemical Spectroscopy

Research output: Contribution to journal › Article › peer-review

26 Scopus citations

Abstract

We investigate the extent to which the alkyl chain on the cation of an imidazolium-based neat room-temperature ionic liquid influences mobility and electrochemical behavior in nanoporous supercapacitors. Changing the cation chain length from an ethyl (n = 2) to a butyl (n = 4) to a hexyl (n = 6) group affects the electrolyte dynamics and their accumulation densities under dynamic charge-discharge processes. We relied on molecular dynamics (MD) computational simulations and classical density functional theory (cDFT) calculations of our system to reinforce the experimental results obtained from electrochemical measurements and quasi-elastic neutron scattering (QENS). We contrast the different dynamics of ionic liquids in bulk and confined states and demonstrate the effect of the cation dimension on resulting arrangements of positive and negative ions in pores. We correlate these fundamental properties with device performance metrics in an effort to properly tailor high-performance carbon supercapacitor electrodes with non-flammable and electrochemically stable electrolytes.

Original language	English
Pages (from-to)	882-893
Number of pages	12
Journal	Electrochimica Acta
Volume	283
DOIs	https://doi.org/10.1016/j.electacta.2018.06.200
State	Published - Sep 1 2018

Funding

This research was supported by the Fluid Interface Reactions, Structures and Transport (FIRST) Center, an Energy Frontier Research Center funded by the U.S. Department of Energy , Office of Science, Office of Basic Energy Sciences. B.D. also acknowledges the DOE Office of Science Graduate Student Research Fellowship (SCGSR). Neutron scattering measurements at ORNL were made available through the Scientific User Facilities Division, Office of Basic Energy Sciences , US Department of Energy. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for U.S. DOE under Contract No. DE-AC05-00OR22725 . This research used resources of the National Energy Research Scientific Computing Center , a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 .

Keywords

Density functional theory
Ionic liquid
Molecular dynamics
Neutron scattering
Supercapacitor

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title = "Electrolyte cation length influences electrosorption and dynamics in porous carbon supercapacitors",

abstract = "We investigate the extent to which the alkyl chain on the cation of an imidazolium-based neat room-temperature ionic liquid influences mobility and electrochemical behavior in nanoporous supercapacitors. Changing the cation chain length from an ethyl (n = 2) to a butyl (n = 4) to a hexyl (n = 6) group affects the electrolyte dynamics and their accumulation densities under dynamic charge-discharge processes. We relied on molecular dynamics (MD) computational simulations and classical density functional theory (cDFT) calculations of our system to reinforce the experimental results obtained from electrochemical measurements and quasi-elastic neutron scattering (QENS). We contrast the different dynamics of ionic liquids in bulk and confined states and demonstrate the effect of the cation dimension on resulting arrangements of positive and negative ions in pores. We correlate these fundamental properties with device performance metrics in an effort to properly tailor high-performance carbon supercapacitor electrodes with non-flammable and electrochemically stable electrolytes.",

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author = "Boris Dyatkin and Osti, \{Naresh C.\} and Alejandro Gallegos and Yu Zhang and Eugene Mamontov and Cummings, \{Peter T.\} and Jianzhong Wu and Yury Gogotsi",

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AU - Dyatkin, Boris

AU - Osti, Naresh C.

AU - Gallegos, Alejandro

AU - Zhang, Yu

AU - Mamontov, Eugene

AU - Cummings, Peter T.

AU - Wu, Jianzhong

AU - Gogotsi, Yury

PY - 2018/9/1

Y1 - 2018/9/1

N2 - We investigate the extent to which the alkyl chain on the cation of an imidazolium-based neat room-temperature ionic liquid influences mobility and electrochemical behavior in nanoporous supercapacitors. Changing the cation chain length from an ethyl (n = 2) to a butyl (n = 4) to a hexyl (n = 6) group affects the electrolyte dynamics and their accumulation densities under dynamic charge-discharge processes. We relied on molecular dynamics (MD) computational simulations and classical density functional theory (cDFT) calculations of our system to reinforce the experimental results obtained from electrochemical measurements and quasi-elastic neutron scattering (QENS). We contrast the different dynamics of ionic liquids in bulk and confined states and demonstrate the effect of the cation dimension on resulting arrangements of positive and negative ions in pores. We correlate these fundamental properties with device performance metrics in an effort to properly tailor high-performance carbon supercapacitor electrodes with non-flammable and electrochemically stable electrolytes.

AB - We investigate the extent to which the alkyl chain on the cation of an imidazolium-based neat room-temperature ionic liquid influences mobility and electrochemical behavior in nanoporous supercapacitors. Changing the cation chain length from an ethyl (n = 2) to a butyl (n = 4) to a hexyl (n = 6) group affects the electrolyte dynamics and their accumulation densities under dynamic charge-discharge processes. We relied on molecular dynamics (MD) computational simulations and classical density functional theory (cDFT) calculations of our system to reinforce the experimental results obtained from electrochemical measurements and quasi-elastic neutron scattering (QENS). We contrast the different dynamics of ionic liquids in bulk and confined states and demonstrate the effect of the cation dimension on resulting arrangements of positive and negative ions in pores. We correlate these fundamental properties with device performance metrics in an effort to properly tailor high-performance carbon supercapacitor electrodes with non-flammable and electrochemically stable electrolytes.

KW - Density functional theory

KW - Ionic liquid

KW - Molecular dynamics

KW - Neutron scattering

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ER -

Electrolyte cation length influences electrosorption and dynamics in porous carbon supercapacitors

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