Pore structure and electrochemical properties of CNT-based electrodes studied by <i>in situ</i> small/wide angle X-ray scattering

Santos, Cleis; Senokos, Evgeny; Fernández-Toribio, Juan C.; Ridruejo, Álvaro; Marcilla, Rebeca; Vilatela, Juan J.

doi:10.1039/c9ta01112a

Cited by 26 publications

(27 citation statements)

References 52 publications

(62 reference statements)

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“…As expected, the SWCNT are of relatively large diameter (> 1 nm) ( Fig.2(c)), at least compared to those produced by standard substrate-based chemical vapor deposition (CVD) in the absense of promotors, but not sufficiently large to collapse into ribbons. The bundle diameter distribution observed by TEM spans from 5-60 nm and peaks at around 20 nm ( Fig.2(d)), which is comparable to the average bundle lateral size determined by small-angle X-ray scattering (9 nm) [22].…”

Section: Exposing Molecular Features In Swcnt Aerogelssupporting

confidence: 71%

Molecular characterization of macroscopic aerogels of single-walled carbon nanotubes

Alemán

Vilatela

2019

Carbon

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Single-walled carbon nanotubes (SWCNT) can be assembled into various macroscopic architectures, most notably continuous fibers and films, produced currently on a kilometer-per-day scale by floating catalyst chemical vapor deposition and spinning from an aerogel of CNTs. An attractive challenge is to produce continuous fibers with controlled molecular structure with respect to the diameter, chiral angle and ultimately (n,m) indices of the constituent SWCNT "molecules". This work presents an extensive Raman spectroscopy and high-resolution transmission electron microscopy study of SWCNT aerogels produced by the direct spinning method. By retaining the open structure of the SWCNT aerogel, we reveal the presence of both semiconducting and metallic SWCNTs and determine a full distribution of families of SWCNT grouped by optical transitions. The resulting distribution matches the chiral angle distribution obtained by electron microscopy and electron diffraction. The effect of SWCNT bundling on the Raman spectra, such as the G − line shape due to plasmons activated in the far-infrared and semiconductor quenching, are also discussed. By avoiding full aggregation of the aerogel and applying the methodology introduced, rapid screening of molecular features can be achieved in large samples, making this protocol a useful analysis tool for engineered SWCNT fibers and related systems.

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Section: Exposing Molecular Features In Swcnt Aerogelssupporting

confidence: 71%

Molecular characterization of macroscopic aerogels of single-walled carbon nanotubes

Alemán

Vilatela

2019

Carbon

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“…This is a consequence of the progressive alignment and aggregation of bundles upon stretching, leading to the pores adopting a more elongated shape and the emergence of the form factor along the equator. From SAXS data we calculate the changes in fibre porosity using the methodology reported earlier [11] (see experimental methods). Figure 2c shows that there is rapid reduction in porosity from 0.74 to 0.69 during tensile deformation of the fibre, which then levels off and remains fairly constant throughout the rest of the test.…”

Section: Resultsmentioning

confidence: 99%

“…No differences in ODF are found between these modes; the microfocus configuration simply increases scattering intensity over background signal, useful for radial profile analysis. SAXS radial profiles were analysed as a two-phase system (CNTs and air) with sharp boundaries after correction for density fluctuations, as detailed in [11]. Porosity (P ) was calculated from the total scattering intensity, the invariant (Q) being…”

Section: Methodsmentioning

confidence: 99%

Understanding cooperative loading in carbon nanotube fibres through in-situ structural studies during stretching

Fernández-Toribio

Mikhalchan

Santos

et al. 2020

Carbon

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Carbon nanotube (CNT) fibres are firmly established as a new high-performance fibre, but their tensile mechanical properties remain a relatively small fraction of those of the constituent CNTs. Clear structure-property relations and accurate mechanical models are pressing requirements to bridge this gap. In this work we analyse the structural evolution and molecular stress transfer in CNT fibres by performing in-situ synchrotron wide-and small-angle X-ray scattering and Raman spectroscopy during tensile deformation. The results show that CNT fibres can be accurately described as network of bundles that slide progressively according to the initial orientation distribution function of the material following a Weibull distribution. This model decouples the effects of CNT alignment and degree of cooperative loading, as demonstrated for fibres produced at different draw ratios. It also helps explain the unusually high toughness (fracture energy) of CNT fibres produced by the direct spinning method, a key property for impact resistance in structural materials, for example.

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“…Their electrical and mechanical properties remain even if they are knotted [34,35]. Additionally, they are highly porous and their specific surface area may range from tens to hundreds of m 2 /g [22,31,32,36,37]. The unique properties of these materials may be applied in electronics in a number of ways.…”

Section: Spun Cnt Fibers and Filmsmentioning

confidence: 99%

“…Additionally, the spun fibers and films are characterized by a high thermal conductivity coupled with mechanical strength, fatigue resistance, specific surface area/porosity and flexibility. Thanks to these properties they show considerable promise as materials for smart textiles, antennas, sensors, capacitors, batteries and many more applications [26][27][28][29][30][31][32]. However, whether they are able to replace printed electronic components in all applications is the key question.…”

Section: Introductionmentioning

confidence: 99%

Spun Carbon Nanotube Fibres and Films as an Alternative to Printed Electronic Components

et al. 2020

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Current studies of carbon nanotubes have enabled both new electronic applications and improvements to the performance of existing ones. Manufacturing of macroscopic electronic components with this material generally involves the use of printed electronic methods, which must use carbon nanotube (CNT) powders. However, in recent years, it has been shown that the use of ready-made self-standing macroscopic CNT assemblies could have considerable potential in the future development of electronic components. Two examples of these are spun carbon nanotube fibers and CNT films. The following paper considers whether these spun materials may replace printed electronic CNT elements in all applications. To enable the investigation of this question some practical experiments were undertaken. They included the formation of smart textile elements, flexible and transparent components, and structural electronic devices. By taking this approach it has been possible to show that CNT fibres and films are highly versatile materials that may improve the electrical and mechanical performance of many currently produced printed electronic elements. Additionally, the use of these spun materials may enable many new applications and functionalities particularly in the area of e-textiles. However, as with every new technology, it has its limitations, and these are also considered.

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Pore structure and electrochemical properties of CNT-based electrodes studied by in situ small/wide angle X-ray scattering

Abstract: The pore structure and surface area of CNT-based electrodes is analysed by SAXS/WAXS, including under eletrochemical measurements.

Cited by 26 publications

References 52 publications

Molecular characterization of macroscopic aerogels of single-walled carbon nanotubes

Molecular characterization of macroscopic aerogels of single-walled carbon nanotubes

Understanding cooperative loading in carbon nanotube fibres through in-situ structural studies during stretching

Spun Carbon Nanotube Fibres and Films as an Alternative to Printed Electronic Components

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