In Situ Synchrotron X-ray Diffraction Studies of Single-walled Carbon Nanotubes for Electric Double-layer Capacitors

Yoshida, Yukihiro; Tsutsui, Masato; Al-zubaidi, Ayar; Ishii, Yosuke; Kawasaki, Shigeo

doi:10.17265/1934-7375/2015.08.005

Cited by 2 publications

(1 citation statement)

References 10 publications

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“…The tube diameter values for the two kinds of SWCNTs, determined by XRD pattern simulations [39], were 1.5 and 2.5 nm for SO and EC type SWCNT samples, respectively (figure S3) [9,40]. Therefore, we will refer here-in-after to SO and EC type SWCNTs as SWCNT-1.5 and -2.5, respectively.…”

Section: Resultsmentioning

confidence: 99%

Quinone molecules encapsulated in SWCNTs for low-temperature Na ion batteries

Ishii

Inayama

et al. 2017

Nanotechnology

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We have performed Li and Na ion charge-discharge experiments of 9,10-phenanthrene quinone (PhQ) molecules encapsulated in single-walled carbon nanotubes (SWCNTs) with mean tube diameters of 1.5 and 2.5 nm at room temperature and also at low temperatures. The Na ion reversible capacity of PhQ encapsulated in the larger diameter SWCNTs, measured at a low temperature of 0 °C, remained as high as that measured at room temperature (RT), while the capacity of PhQ in the smaller diameter SWCNTs at 0 °C was about a half of that at RT. The diameter dependence of the capacity should be attributed to the difference in the interactions between the encapsulated PhQ molecules and the host SWCNTs, which was revealed by Raman peak profile analysis. Charge-transfer reaction from metallic tubes to PhQ molecules encapsulated in the smaller diameter SWCNTs was detected by Raman measurements. The electrostatic interaction between charged SWCNTs and PhQ molecules, induced by the charge-transfer reaction, would partly contribute to the stabilization of PhQ molecules in the smaller diameter SWCNTs, while only van der Waals interaction stabilizes PhQ molecules in the larger diameter SWCNTs. The difference in stability was confirmed by thermogravimetric, x-ray photoelectron spectroscopy, and Raman measurements. Charge-discharge curves of PhQ encapsulated in SWCNTs were also discussed based on the stability difference.

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Section: Resultsmentioning

confidence: 99%

Quinone molecules encapsulated in SWCNTs for low-temperature Na ion batteries

Ishii

Inayama

et al. 2017

Nanotechnology

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Low-Temperature Phase Transformation Accompanied with Charge-Transfer Reaction of Polyiodide Ions Encapsulated in Single-Walled Carbon Nanotubes

et al. 2016

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In order to understand the reason why polyiodide ions encapsulated in single-walled carbon nanotubes (SWCNTs) drastically improve the electric conductivity and the water dispersibility of SWCNTs at low temperature, we performed in situ Raman measurements of polyiodide ions encapsulated in three kinds of SWCNTs having different mean tube diameters under low temperature down to −100 °C. It was found that, for all the three samples, the Raman peak intensities of polyiodide ions increase and the G-band peak position of SWCNTs shifts toward the higher-wavenumber side with decreasing temperature. It means that the charge-transfer from SWCNTs to encapsulated iodine molecules increases with decreasing temperature and that hole-doping level of SWCNTs increases at low temperature. Furthermore, the peak profiles changed with temperature drastically for polyiodide ions encapsulated in the SWCNT sample having the largest mean tube diameter of 2.5 nm. This change indicates the structural transformation of polyiodide ions in SWCNTs. These experimental results can be explained by the promotion of the chain-like polyiodide ion formation at low temperature. It was discussed with the control experiment using amylose that the promotion of the polyiodide ion formation at low temperature is characteristic for iodine molecules encapsulated in SWCNTs.

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In Situ Synchrotron X-ray Diffraction Studies of Single-walled Carbon Nanotubes for Electric Double-layer Capacitors

Cited by 2 publications

References 10 publications

Quinone molecules encapsulated in SWCNTs for low-temperature Na ion batteries

Quinone molecules encapsulated in SWCNTs for low-temperature Na ion batteries

Low-Temperature Phase Transformation Accompanied with Charge-Transfer Reaction of Polyiodide Ions Encapsulated in Single-Walled Carbon Nanotubes

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