Anomalous thermal transition and crystallization of ionic liquids confined in graphene multilayers

Im, Jinkyu; Cho, Sung Dae; Kim, Min Hye; Jung, Young Mee; Kim, Hoon Sik; Park, Ho Seok

doi:10.1039/c2cc16367e

Cited by 35 publications

(27 citation statements)

References 33 publications

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“…During this exfoliation process, the ILs serve as exfoliating and functionalizing agents. The ILs interact with the m‐MoS 2 and Gr sheets by electrostatic and π–π interactions (Figure S5, Supporting Information) and prevent the re‐aggregation of the 2D nanosheets, resulting in enhanced yields and concentrations. Indeed, these exfoliation performances are remarkable because the yield and production rate values are much higher than those reported for other solution‐based exfoliation methods (yields < 15%; production rates < 5.3 g h −1 ), including sonication exfoliation, redox exfoliation, pressure homogenization, and shear exfoliation .…”

Section: Resultsmentioning

confidence: 99%

Scalable Water‐Based Production of Highly Conductive 2D Nanosheets with Ultrahigh Volumetric Capacitance and Rate Capability

Jeon

Jeong

Kang

et al. 2018

Advanced Energy Materials

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Highly conductive and ultrathin 2D nanosheets are of importance for the development of portable electronics and electric vehicles. However, scalable production and rational design for highly electronic and ionic conductive 2D nanosheets still remain a challenge. Herein, an industrially adoptable fluid dynamic exfoliation process is reported to produce large quantities of ionic liquid (IL)‐functionalized metallic phase MoS2 (m‐MoS2) and defect‐free graphene (Gr) sheets. Hybrid 2D–2D layered films are also fabricated by incorporating Gr sheets into compact m‐MoS2 films. The incorporated IL functionalities and Gr sheets prevent aggregation and restacking of the m‐MoS2 sheets, thereby creating efficient and rapid ion and electron pathways in the hybrid films. The hybrid film with a high packing density of 2.02 g cm−3 has an outstanding volumetric capacitance of 1430.5 F cm−3 at 1 A g−1 and an extremely high rate capability of 80% retention at 1000 A g−1. The flexible supercapacitor assembled using a polymer‐gel electrolyte exhibits excellent resilience to harsh electrochemical and mechanical conditions while maintaining an impressive rate performance and long cycle life. Successful achievement of an ultrahigh volumetric energy density (1.14 W h cm−3) using an organic electrolyte with a wide cell voltage of ≈3.5 V is demonstrated.

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Section: Resultsmentioning

confidence: 99%

Scalable Water‐Based Production of Highly Conductive 2D Nanosheets with Ultrahigh Volumetric Capacitance and Rate Capability

Jeon

Jeong

Kang

et al. 2018

Advanced Energy Materials

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“…An understanding of the properties of the ILs confined in a nanoscaleconstrained geometry is of both fundamental and practical interest. In particular, the spatial restriction and low dimensionality promote a strong interaction of the ILs with the walls of the confining matrix, resulting in physicochemical behavior of the confined ILs, in terms of phase transition behavior [29][30][31], wetting [32], layering near surface walls [33,34], as well as mobility [35][36][37], much different from the corresponding bulk properties.…”

Section: Introductionmentioning

confidence: 99%

Ionic liquids under nanoscale confinement

Borghi

Podestà

2020

Advances in Physics: X

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The confinement of room-temperature ionic liquids (ILs) in nanoscale geometries, where at least one, but often all three dimensions are reduced down to lengths comparable to the anion-cation size, put the ILs into a quite different condition with respect to their bulk phase. An understanding of the properties of the ILs confined in a nanoscale-constrained geometry is of both fundamental and practical interest. In particular, the spatial restriction of ILs promotes a strong interaction of the ILs with the surface of the confining matrix, which strongly affects their properties, like the phase transition behavior, layering near surface walls, wetting, as well as ionic mobility. This short review is especially concerned with the interfacial confinement of ILs on solid substrates, in the form of very thin films, or inside porous nanomaterials.

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“…However, the resulting hybrid materials represent an almost unexplored area. To date, most investigations havefocused on ILs in inorganic porous matrices 20 such as SiO 2 , 21 TiO 2 , 20 and SnO 2 22 as well as organic porous matrices such as carbon nanotubes, 23 graphene, 24 and porous carbon. 25 The hybrid material is known as an ionogel, 20 in which the IL is kept inside the porous skeleton.…”

Section: Introductionmentioning

confidence: 99%

Removal of Confined Ionic Liquid from a Metal Organic Framework by Extraction with Molecular Solvents

et al. 2017

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Hybrid materials of ionic liquids (IL) confined in metal organic frameworks (MOF) are promising materials for energy storage. The effects of exposing or treating such composite materials with molecular solvents, e.g. with the aim to extract and replace the IL, have not been studied to date. In this study, acetone, isopropanol, methanol, and water were used to remove the IL 1-ethyl-3-methylimidazolium ethyl sulfate confined in a Cu-based metal organic framework (CuBTC). The consequences of the solvent extraction process were analyzed using vibrational spectroscopy (FTIR), powder X-ray diffraction (PXRD), N 2 adsorption, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Methanol was identified as the best solvent for IL removal as it shows high extraction efficiency without affecting the porous geometry and crystal structure of the MOF. On the other hand, acetone and isopropanol were not able to completely remove the IL from CuBTC under the conditions employed. Water effectively removed the IL, but it has a significant detrimental effect on the CuBTC structure.This impact manifests as changes in the infrared spectra and the PXRD patterns as well as in the electron micrographs. The degraded CuBTC exhibits a non-porous structure that presents itself as non-uniformly agglomerated micro-rods along with very few hexagonal/amorphous phases.The confinement of acetone, isopropanol, and methanol in the MOF was also investigated. The results show that CuBTC is stable in acetone, isopropanol, and methanol but unstable in water.

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Anomalous thermal transition and crystallization of ionic liquids confined in graphene multilayers

Cited by 35 publications

References 33 publications

Scalable Water‐Based Production of Highly Conductive 2D Nanosheets with Ultrahigh Volumetric Capacitance and Rate Capability

Scalable Water‐Based Production of Highly Conductive 2D Nanosheets with Ultrahigh Volumetric Capacitance and Rate Capability

Ionic liquids under nanoscale confinement

Removal of Confined Ionic Liquid from a Metal Organic Framework by Extraction with Molecular Solvents

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