Enhancement of Volumetric Capacitance of Binder-Free Single-Walled Carbon Nanotube Film via Fluorination.

Olga A Gurova,Vitalii I Sysoev,Igor P Asanov,Lyubov G Bulusheva,Egor V Lobiak,Leonid V Kulik,Alexander V Okotrub,Anna A Makarova

doi:10.3390/nano11051135

Olga A Gurova, Vitalii I Sysoev + Show 6 more

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https://doi.org/10.3390/nano11051135

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Journal: Nanomaterials	Publication Date: Apr 27, 2021
Citations: 8	License type: CC BY 4.0

Affiliation: Nikolaev Institute of Inorganic Chemistry

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Robust electrode materials without the addition of binders allow increasing efficiency of electrical storage devices. We demonstrate the fabrication of binder-free electrodes from modified single-walled carbon nanotubes (SWCNTs) for electrochemical double-layer capacitors (EDLCs). Modification of SWCNTs included a sonication in 1,2-dichlorobenzene and/or fluorination with gaseous BrF3 at room temperature. The sonication caused the shortening of SWCNTs and the splitting of their bundles. As a result, the film prepared from such SWCNTs had a higher density and attached a larger amount of fluorine as compared to the film from non-sonicated SWCNTs. In EDLCs with 1M H2SO4 electrolyte, the fluorinated films were gradually defluorinated, which lead to an increase of the specific capacitance by 2.5–4 times in comparison with the initial values. Although the highest gravimetric capacitance (29 F g−1 at 100 mV s−1) was observed for the binder-free film from non-modified SWCNT, the fluorinated film from the sonicated SWCNTs had an enhanced volumetric capacitance (44 F cm−3 at 100 mV s−1). Initial SWCNT films and defluorinated films showed stable work in EDLCs during several thousand cycles.

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Published: 27 April 2021The depletion of fossil fuels causes fluctuations in their price and leads to problems with pollution of air and soil
Porous types of carbon materials are widely used in electrochemical double-layer capacitors (EDLCs), because they have a high specific surface area and developed microporous structure, but they are unfavorable for electrolyte wetting and rapid ionic transport [10]
The former sample consists of entangled single-walled carbon nanotubes (SWCNTs) bundles with an average diameter of ca. 100–200 nm (Figure 1a)

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Published: 27 April 2021The depletion of fossil fuels causes fluctuations in their price and leads to problems with pollution of air and soil. Recently there has been a growing interest in the development of highly efficient energy storage devices, including solar cells [1,2], rechargeable batteries [3], and electrochemical double-layer capacitors (EDLCs) [4,5]. Batteries possess high energy density, but they have low power density [7,8]. Porous types of carbon materials are widely used in EDLCs, because they have a high specific surface area and developed microporous structure, but they are unfavorable for electrolyte wetting and rapid ionic transport [10]. For the fabrication of electrodes from porous carbon materials, a polymer binder is required to hold the carbon particles together. When the mass of the electrochemically inactive binder is taken into account, the specific capacitance of the electrode decreases [11]

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