Study of the porosity of mesophase and its carbonization products

Weishauptová, Zuzana; Medek, J.; vaverková, Z.

doi:10.1016/0008-6223(94)90194-5

Cited by 9 publications

(6 citation statements)

References 7 publications

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“…The pore structure of the activated MPCFs characterized by gas adsorption is shown in Figures S2 and S3 and Table S1. [16] The inset images were obtained by using a bird's eye view of a selected area of each image, which converts the 2D image to a 3D one. High-resolution (HR)TEM observations reveal that carbon skeletons with a densely entangled graphene network structure are lost after the KOH activation of MPCF-650 ( Figure 2 a and b).…”

Section: Resultsmentioning

confidence: 99%

“…This can be explained by the presence of the intergraphene layer gaps, which correspond to intermolecular dimensions and can be interpreted as micropores, as supported by gas adsorption results. [16] The inset images were obtained by using a bird's eye view of a selected area of each image, which converts the 2D image to a 3D one. The height along the z-axis in the 3D images corresponds to the brightness in the 2D images.…”

Section: Resultsmentioning

confidence: 99%

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Edge‐Enriched, Porous Carbon‐Based, High Energy Density Supercapacitors for Hybrid Electric Vehicles

et al. 2012

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Supercapacitors can store and deliver energy by a simple charge separation, and thus they could be an attractive option to meet transient high energy density in operating fuel cells and in electric and hybrid electric vehicles. To achieve such requirements, intensive studies have been carried out to improve the volumetric capacitance in supercapacitors using various types and forms of carbons including carbon nanotubes and graphenes. However, conventional porous carbons are not suitable for use as electrode material in supercapacitors for such high energy density applications. Here, we show that edge-enriched porous carbons are the best electrode material for high energy density supercapacitors to be used in vehicles as an auxiliary powertrain. Molten potassium hydroxide penetrates well-aligned graphene layers vertically and consequently generates both suitable pores that are easily accessible to the electrolyte and a large fraction of electrochemically active edge sites. We expect that our findings will motivate further research related to energy storage devices and also environmentally friendly electric vehicles.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Edge‐Enriched, Porous Carbon‐Based, High Energy Density Supercapacitors for Hybrid Electric Vehicles

et al. 2012

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“…The micropores have outlets on the surfaces of the meso-and macropores, and therefore, the number of accessible micropores, proportional to surface S micro , depends on the surface area of the meso-and macropores included in the value of S BET . 21 Table III summarizes the characteristic properties obtained by the BET analyses. As mentioned above, in both series of samples, the micropore volume increases as the specific surface area increases.…”

Section: Resultsmentioning

confidence: 99%

“…Besides, with mesophase pitch it is easy to construct a ribbonlike planar layer, so it is inferred that the pore structures from the MP-series of samples have a slit shape. 21 The pore shape can help to prevent the bottleneck effect (The present bottle-neck condition was compared to the traffic congestion, which happens if the electrolyte ions gather simultaneously at a narrow entrance like the neck of a bottle) of the electrolyte ion, when the cell is charged or discharged. Figure 9 shows the variation of the ESR with discharge current density variation when the cell is charged until 3.5 V. As shown in the figure, AC-a has the largest ESR value, that is, the worse conductivity.…”

Section: Resultsmentioning

confidence: 99%

Morphological effect on the electrochemical behavior of electric double-layer capacitors

et al. 2001

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Activated milled mesophase carbon fibers (AC-mMPCF, MP-series) show a higher specific capacitance in spite of a smaller specific surface area than those of powder-type activated carbons (AC-series). This phenomenon can be interpreted to mean that it is difficult to predict the capacitance of an electric double-layer capacitor (EDLC) knowing just the surface area and the pore size. More information is needed about other inherent characteristics of the samples, for example, the equivalent series resistance (ESR), shape of the pores, etc. We investigate here other characteristics of the samples. Consequently, it was deduced that the MP-series of EDLCs have a slit pore shape, which affects the accessibility of the electrolyte ion onto the electrode surface. Moreover, the MP-series of materials have suitable ESR values, and these material properties themselves should be considered as factors that affects the deterioration of the specific capacitance of EDLCs.

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“…[179][180][181] At room temperature coal tar pitch is a brittle material with a conchoidal fracture and is from dark brown to black in color. 182 Hydrocarbons with a high amount of heteroatoms, alkyl substituents and benzene rings influence coal tar pitch reactivity, enhance cross-linking and polymerisation. This effect is intensified at temperatures above 450°C, when polycondensed aromatic systems with a much bigger molecular mass (mesophase) are produced.…”

Section: Pitchmentioning

confidence: 99%

Review of the Selected Carbon-Based Materials for Symmetric Supercapacitor Application

Ciszewski

Koszorek

Radko

et al. 2018

Journal of Elec Materi

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Carbon materials are among the most commonly used components of supercapacitor electrodes. Particularly, active carbons are recognized as cheap, available, and easily tailored materials. However, the carbon family, i.e. carbon products and carbon precursors, consists of many members. In this manuscript some of these materials, including laboratory scale-produced carbon gels, carbon nanotubes and carbonized materials, as well as industrial scale-produced graphites, pitches, coke and coal, were compared. Discussion was preceded by a short history of supercapacitors and review of each type of tested material, from early beginning to state-of-the-art. Morphology and structure of the materials were analyzed (specific surface area, pore volume and interlayer spacing determination), to evaluate their applicability in energy storage. Thermal analysis was used to determine the stability and purity. Finally, electrochemical evaluation using cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy was performed. Outcomes of each analytical technique were summarized in different sections.

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Study of the porosity of mesophase and its carbonization products

Cited by 9 publications

References 7 publications

Edge‐Enriched, Porous Carbon‐Based, High Energy Density Supercapacitors for Hybrid Electric Vehicles

Edge‐Enriched, Porous Carbon‐Based, High Energy Density Supercapacitors for Hybrid Electric Vehicles

Morphological effect on the electrochemical behavior of electric double-layer capacitors

Review of the Selected Carbon-Based Materials for Symmetric Supercapacitor Application

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