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Title

Effect of oxygenated functionalities on the phase transitions of an ionic liquid confined in a mesoporous carbon host

Authors

[ 1 ] Instytut Chemii i Elektrochemii Technicznej, Wydział Technologii Chemicznej, Politechnika Poznańska | [ P ] employee | [ D ] phd student | [ SzD ] doctoral school student

Scientific discipline (Law 2.0)

[6.5] Chemical sciences

Year of publication

2023

Published in

Carbon

Journal year: 2023 | Journal volume: vol. 202, part 1

Article type

scientific article

Publication language

english

Keywords
EN
  • Ionic liquid confinement
  • Oxidized mesoporous carbons
  • Phase transitions
  • Interfacial and intermolecular interactions
  • Differential scanning calorimetry
  • Raman spectroscopy
Abstract

EN The effect of surface functionalization on the carbon walls-ionic liquid (IL) interactions is analyzed by combining differential scanning calorimetry (DSC) and Raman spectroscopy. Four mesoporous carbons (Lmeso ~ 9.0 nm) with a gradually increasing oxygenated surface functionality have been soaked with the 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide ([EMIm+][FSI−]) IL at filling ratios R ≈ 0.8 (almost complete pore fullness) and R ≈ 1.2 (fully filled pores with excess liquid). The low temperature behavior of the IL molecules confined in mesopores depends on their distribution between two populations: i) located close to the pore center, or ii) near the pore walls. In the surface clean material soaked with R ≈ 0.8, the molecules in the proximity of the pore center are involved in freezing/melting, whereas the species located in the vicinity of the pore walls are involved in a glass transition upon cooling, followed by cold crystallization and melting upon heating. When applying the functionalized carbon hosts, all the species located near the pore surface freeze already upon cooling, owing to their aggregation to the walls through the formation of hydrogen bonds with the surface oxygenated functionality. The amount of [EMIm+][FSI−] exhibiting exclusively freezing/melting can be as well enhanced by completely filling the pores (R ≈ 1.2) to strengthen the IL-IL and IL-carbon interactions. The information derived from this study is crucial for designing an optimal porous carbon-IL system intended to be implemented in e.g., electrochemical capacitors (ECs) operating at low temperature.

Date of online publication

19.09.2022

Pages (from - to)

571 - 582

DOI

10.1016/j.carbon.2022.09.049

URL

https://www.sciencedirect.com/science/article/pii/S0008622322007734?via%3Dihub

License type

CC BY (attribution alone)

Open Access Mode

open journal

Open Access Text Version

final published version

Release date

19.09.2022

Date of Open Access to the publication

at the time of publication

Full text of article

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Access level to full text

public

Ministry points / journal

140.0

Impact Factor

11.307 [List 2021]

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