Nanostructure characterization of carbide-derived carbons by morphological analysis of transmission electron microscopy images combined with physisorption and Raman spectroscopy

Oschatz, Martin; Pré, Pascaline; Dörfler, Susanne; Nickel, Winfried; Beaunier, Patricia; Rouzaud, Jean-Noël; Fischer, Cathleen; Brunner, Eike; Kaskel, Stefan

doi:10.1016/j.carbon.2016.04.041

Cited by 56 publications

(47 citation statements)

References 55 publications

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“…In the Raman spectra, the similar peak height ratio of the D (≈1340 cm −1 , breathing mode of sp 2 ‐carbon atoms in aromatic rings) and G bands (≈1580 cm −1 , sp 2 ‐carbon organized in chains or rings) ( I D / I G in Table ) suggests the comparable degree of aromatization for all the samples. The broad D bands in all samples reveal the existence of abundant disordered sections which are typical for amorphous carbons . The slight decrease of FWHM with increasing temperature indicates the higher graphitization degree and carbon content (Figure S4, Supporting Information and Table ).…”

Section: Resultsmentioning

confidence: 95%

Understanding the Charge Storage Mechanism to Achieve High Capacity and Fast Ion Storage in Sodium‐Ion Capacitor Anodes by Using Electrospun Nitrogen‐Doped Carbon Fibers

Yan

Josef

Huang

et al. 2019

Adv Funct Materials

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Microporous nitrogen-rich carbon fibers (HAT-CNFs) are produced by electrospinning a mixture of hexaazatriphenylene-hexacarbonitrile (HAT-CN) and polyvinylpyrrolidone and subsequent thermal condensation. Bonding motives, electronic structure, content of nitrogen heteroatoms, porosity, and degree of carbon stacking can be controlled by the condensation temperature due to the use of the HAT-CN with predefined nitrogen binding motives. The HAT-CNFs show remarkable reversible capacities (395 mAh g −1 at 0.1 A g −1 ) and rate capabilities (106 mAh g −1 at 10 A g −1 ) as an anode material for sodium storage, resulting from the abundant heteroatoms, enhanced electrical conductivity, and rapid charge carrier transport in the nanoporous structure of the 1D fibers. HAT-CNFs also serve as a series of model compounds for the investigation of the contribution of sodium storage by intercalation and reversible binding on nitrogen sites at different rates. There is an increasing contribution of intercalation to the charge storage with increasing condensation temperature which becomes less active at high rates. A hybrid sodium-ion capacitor full cell combining HAT-CNF as the anode and salt-templated porous carbon as the cathode provides remarkable performance in the voltage range of 0.5-4.0 V (95 Wh kg −1 at 0.19 kW kg −1 and 18 Wh kg −1 at 13 kW kg −1 ).

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Section: Resultsmentioning

confidence: 95%

Understanding the Charge Storage Mechanism to Achieve High Capacity and Fast Ion Storage in Sodium‐Ion Capacitor Anodes by Using Electrospun Nitrogen‐Doped Carbon Fibers

Yan

Josef

Huang

et al. 2019

Adv Funct Materials

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“…In PFG NMR experiments magnetic field gradient pulses are used to encode and decode the positions of the nuclear spins, with ionic diffusion probed over a given These marked reductions could arise from a number of factors: (i) the local reduction in in-pore diffusion due to collisions with the rigid pore walls, 30,31 (ii) tortuosity arising from the disordered arrangement of pores [32][33][34] in the carbon particles such that ions diffuse in an indirect way, and (iii) the structure and composition of the electrolyte in the pores may differ from neat electrolyte, our previous studies having shown that ions are partially desolvated in the pores. 6 The difference in diffusion coefficients between anions and cations is amplified upon confinement in the pores (Figure 2a), highlighting the important role of ion size, with the larger cations presumably taking more indirect pathways through the pore network (as the smallest pores are inaccessible).…”

Section: Resultsmentioning

confidence: 99%

Direct observation of ion dynamics in supercapacitor electrodes using in situ diffusion NMR spectroscopy

et al. 2017

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Ionic transport inside porous carbon electrodes underpins the storage of energy in supercapacitors and the rate at which they can charge and discharge, yet few studies have elucidated the materials properties that influence ion dynamics. Here we use in situ pulsed field gradient NMR spectroscopy to measure ionic diffusion in supercapacitors directly. We find that confinement in the nanoporous electrode structures decreases the effective self-diffusion coefficients of ions by over two orders of magnitude compared to neat electrolyte, and in-pore diffusion is modulated by changes in ion populations at the electrode-electrolyte interface during charging.Electrolyte concentration and carbon pore size distributions also affect in-pore diffusion and the movement of ions in and out of the nanopores. In light of our findings we propose that controlling the charging mechanism may allow the tuning of the energy and power performances of supercapacitors for a range of different applications.As renewable energy and green technologies such as electric vehicles become prevalent, we must develop new ways to store and release energy on a range of timescales. Rechargeable batteries are ideal for timescales of minutes or hours (electric cars, portable electronic devices, grid storage etc.), while supercapacitors are more promising for second or sub-second timescales and are increasingly being used for transport applications where rapid charging and discharging are required. The superior power handling and cycle lifetime of supercapacitors comes at the expense of energy density, with recent materials-driven research aiming to address this issue by fine-tuning the nanoporous structure of the carbon electrodes, 1,2 and by using ionic liquid electrolytes that are stable at higher voltages. 3,4 Both approaches have afforded some increases in energy density, though not without sacrificing power density. The delicate balance between energy and power density must be understood if supercapacitors are to be used in a wide range of applications.Fundamental studies based on spectroscopic, 5-14 and theoretical, 15-18 methods have recently revealed the complex nature of charging in supercapacitors. Prior to charging, the electrode pores contain a large number of electrolyte ions, 15,19,20 and as a result charge storage is generally more complex than simple counter-ion adsorption (counter-ions are defined as having charge opposite to the electrode in which they are located). [5][6][7]15 A range of different charging mechanisms can operate

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“…That band was not observed on disordered samples studied by Pardanaud et al [66], using UV, due to resonance effects. We believe that in situ multiwavelength Raman spectroscopy coupled to skeleton analysis of TEM images (like the one performed by Oschatz et al [228], or by Da Costa et al [229]) performed on stressed nanocones could be the next insight to pave the way between 2D ordered and 3D disordered aromatic carbons, especially by taking advantage of resonance effects. were able to produce a peak which is close to 1550 cm −1 , 40 cm −1 away from the detected position.…”

Section: Nanoconesmentioning

confidence: 98%

A Guide to and Review of the Use of Multiwavelength Raman Spectroscopy for Characterizing Defective Aromatic Carbon Solids: from Graphene to Amorphous Carbons

2017

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sp 2 hybridized carbons constitute a broad class of solid phases composed primarily of elemental carbon and can be either synthetic or naturally occurring. Some examples are graphite, chars, soot, graphene, carbon nanotubes, pyrolytic carbon, and diamond-like carbon. They vary from highly ordered to completely disordered solids and detailed knowledge of their internal structure and composition is of utmost importance for the scientific and engineering communities working with these materials. Multiwavelength Raman spectroscopy has proven to be a very powerful and non-destructive tool for the characterization of carbons containing both aromatic domains and defects and has been widely used since the 1980s. Depending on the material studied, some specific spectroscopic parameters (e.g., band position, full width at half maximum, relative intensity ratio between two bands) are used to characterize defects. This paper is addressed first to (but not limited to) the newcomer in the field, who needs to be guided due to the vast literature on the subject, in order to understand the physics at play when dealing with Raman spectroscopy of graphene-based solids. We also give historical aspects on the development of the Raman spectroscopy technique and on its application to sp 2 hybridized carbons, which are generally not presented in the literature. We review the way Raman spectroscopy is used for sp 2 based carbon samples containing defects. As graphene is the building block for all these materials, we try to bridge these two worlds by also reviewing the use of Raman spectroscopy in the characterization of graphene and nanographenes (e.g., nanotubes, nanoribbons, nanocones, bombarded graphene). Counterintuitively, because of the Dirac cones in the electronic structure of graphene, Raman spectra are driven by electronic properties: Phonons and electrons being coupled by the double resonance mechanism. This justifies the use of multiwavelength Raman spectroscopy to better characterize these materials. We conclude with the possible influence of both phonon confinement and curvature of aromatic planes on the shape of Raman spectra, and discuss samples to be studied in the future with some complementary technique (e.g., high resolution transmission electron microscopy) in order to disentangle the influence of structure and defects.

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Nanostructure characterization of carbide-derived carbons by morphological analysis of transmission electron microscopy images combined with physisorption and Raman spectroscopy

Cited by 56 publications

References 55 publications

Understanding the Charge Storage Mechanism to Achieve High Capacity and Fast Ion Storage in Sodium‐Ion Capacitor Anodes by Using Electrospun Nitrogen‐Doped Carbon Fibers

Understanding the Charge Storage Mechanism to Achieve High Capacity and Fast Ion Storage in Sodium‐Ion Capacitor Anodes by Using Electrospun Nitrogen‐Doped Carbon Fibers

Direct observation of ion dynamics in supercapacitor electrodes using in situ diffusion NMR spectroscopy

A Guide to and Review of the Use of Multiwavelength Raman Spectroscopy for Characterizing Defective Aromatic Carbon Solids: from Graphene to Amorphous Carbons

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