Defective 3D nitrogen-doped carbon nanotube-carbon fibre networks for high-performance supercapacitor: Transformative role of nitrogen-doping from surface-confined to diffusive kinetics

Mofokeng, Thapelo P.; Tetana, Zikhona N.; Ozoemena, Kenneth I.

doi:10.1016/j.carbon.2020.07.049

Cited by 87 publications

(38 citation statements)

References 75 publications

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“…The Gaussian curve for the D 3 band was used as it gave a superior fit to the original spectrum. The disordered graphitic lattice peaks (A 1g symmetry) are observed at D 4 (1200 cm −1 ), D 3 (1500 cm −1 ) and D 2 (1620 cm −1 ), respectively [65, 66].…”

Section: Resultsmentioning

confidence: 99%

Physicochemical Properties of Nitrogen Doped Carbon Nano‐onions Grown by Flame Pyrolysis from Grapeseed Oil for Use in Supercapacitors

et al. 2020

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A low cost synthesis of catalyst free carbon nano-onions (CNOs) and nitrogen post doped CNOs (NÀ CNOs) using grapeseed oil is reported. Successful incorporation of nitrogen atoms into the lattice of CNOs was confirmed by XPS, resulting in 1.7 % nitrogen content. BET and Raman analysis showed an increase in the specific surface area and the I D /I G ratio of carbon, respectively after N incorporation. The specific capacitance of the CNOs increased upon nitrogen doping and as a result, NÀ CNOs exhibited superior electrochemical performance compared to pristine CNOs. Our results demonstrate that NÀ CNOs are a promising electrode material for energy storage in supercapacitors.

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Section: Resultsmentioning

confidence: 99%

Physicochemical Properties of Nitrogen Doped Carbon Nano‐onions Grown by Flame Pyrolysis from Grapeseed Oil for Use in Supercapacitors

et al. 2020

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“…The structure, defects, and disordered nature of the carbon materials could be determined by Raman spectroscopy. The Raman spectra for GM-derived AC materials using different activating agents and N-dopants are shown in Figure 4 C. The D-band around 1345 cm −1 was related to the sp [ 3 ] carbon sites, indicating that the defect peak arises due to the A1g mode of vibration. The nearby peak around 1580 cm −1 represents the G-band related to the sp [ 2 ] carbon sites, and indicates the graphitic peak [ 40 ].…”

Section: Resultsmentioning

confidence: 99%

“…Various carbonaceous materials—such as activated carbon (AC), carbon nanotubes (CNTs), carbon aerogels, graphene, ordered mesoporous carbon, carbon composites, etc. [ 2 , 3 ]—have been widely reported for their double-layer capacitive behavior and potential applications in supercapacitor devices. Among the carbonaceous materials reported in the literature for electrodes, AC is the most widely used, due to its high surface area and moderate production cost [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

Repurposing N-Doped Grape Marc for the Fabrication of Supercapacitors with Theoretical and Machine Learning Models

et al. 2022

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Porous carbon derived from grape marc (GM) was synthesized via carbonization and chemical activation processes. Extrinsic nitrogen (N)-dopant in GM, activated by KOH, could render its potential use in supercapacitors effective. The effects of chemical activators such as potassium hydroxide (KOH) and zinc chloride (ZnCl2) were studied to compare their activating power toward the development of pore-forming mechanisms in a carbon electrode, making them beneficial for energy storage. GM carbon impregnated with KOH for activation (KAC), along with urea as the N-dopant (KACurea), exhibited better morphology, hierarchical pore structure, and larger surface area (1356 m2 g−1) than the GM carbon activated by ZnCl2 (ZnAC). Moreover, density functional theory (DFT) investigations showed that the presence of N-dopant on a graphite surface enhances the chemisorption of O adsorbates due to the enhanced charge-transfer mechanism. KACurea was tested in three aqueous electrolytes with different ions (LiOH, NaOH, and NaClO4), which delivered higher specific capacitance, with the NaOH electrolyte exhibiting 139 F g−1 at a 2 mA current rate. The NaOH with the alkaline cation Na+ offered the best capacitance among the electrolytes studied. A multilayer perceptron (MLP) model was employed to describe the effects of synthesis conditions and physicochemical and electrochemical parameters to predict the capacitance and power outputs. The proposed MLP showed higher accuracy, with an R2 of 0.98 for capacitance prediction.

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“…The as-designed P@PC-AC in aqueous electrolyte delivered a good energy density of 7.47 W h kg −1 at the power density of 221 W kg −1 and retained 3.6 W h kg −1 at the power density of 6749 W kg −1 , which exhibits a comparable performance with very recently reported SSC devices. [35][36][37][38][39][40] We expect that significantly enhanced energy density can be achieved by hetero-atom doping or the incorporation with pseudocapacitive materials such as MnO 2 , polypyrrole, Fe 2 O 3 . Another key requirement for the practical application of supercapacitors is the long cycle stability.…”

Section: Resultsmentioning

confidence: 99%

Novel Gram‐Scale Synthesis of Carbon Nano‐Onions from Heavy Oil for Supercapacitors

Liu

Tang

Han

et al. 2021

Adv Materials Inter

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Moreover, the abundant nanovoids on the sp 2 -hybridized carbon shell and interior space of CNOs facilitate the loading of pseudocapacitive species (metal oxides, [11] the conductive polymer, [12] functional groups, [13,14] etc.) and corresponding charge transport during the charge-storage process. Although fascinating performance has been achieved by CNOs, the efficient synthesis of CNOs remains a great challenge, seriously impeding its application in supercapacitors.Great efforts have been made on the synthesis of CNOs in the past decades. Series of synthetic techniques such as chemical vapor deposition (CVD), [15] underwater electric arc discharge, [16] carbon ion implantation, [17] and annealing of nanodiamonds [18] have been developed to achieve CNOs with tunable sizes (5-200 nm), shapes (spherical and polyhedral), and types of cores (hollow and dense). Among various techniques, chemical methods including CVD, the thermal transformation of nanodiamonds, and thermal pyrolysis of carbon precursor were considered as more viable methods for the production of CNOs, especially in large-scale (gram quantities). For instance, Chen et al. [19] reported a gramscale CVD synthesis of hollow CNOs with MgO supported Co as the catalyst. The hollow CNOs consist of defective carbon shells with diameters ranging from 10 to 50 nm. Recently, the functionalized onion-like graphitic carbon nanospheres (5-30 nm in diameter) were fabricated by a high-temperature transformation of nanodiamonds at 2700 °C, providing the high surface area with multiple oxygen functional groups for enhanced Li-ion storage. [20] Nevertheless, these techniques still suffer from the use of large contents of catalyst (>50 wt%) and high temperature (>1700 °C) [21] in the gram-scale synthesis of CNOs.Herein, we demonstrate a novel bubble template for efficient assembly of CNOs at gram-scale, by using sticky pitch to coat on petroleum coke. The corresponding formation mechanism was proposed and the key feature of this approach is the confinement of petroleum coke generated gas bubbles (H 2 ) to serve as the pristine fragments of graphitic shells for the assembly of CNOs. The as-synthesized CNOs present a uniform particle size of ≈5-30 nm, a superior surface area up to 2665.5 m 2 g −1 , and a large pore volume of 1.2 cm 3 g −1 , which favor the ionic diffusion as well as electronic transport in supercapacitors. Significantly, the CNOs electrode delivered a high specific capacitance of 312 F g −1 at 1 A g −1 and retained as high Carbon nano-onions (CNOs), recognized as multilayered fullerenes, display superior electrical conductivity (comparable with carbon black) and large surface area due to the highly defective sp 2 carbon shells, making it a promising member of carbon nanomaterials for energy applications. However, the lack of efficient synthesis of CNOs in large-scale production (gram quantities) has impeded their range of commercial applications. Herein, for the first time, it is demonstrated that the gram-scale synthesis of CNOs is developed by simply an...

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Defective 3D nitrogen-doped carbon nanotube-carbon fibre networks for high-performance supercapacitor: Transformative role of nitrogen-doping from surface-confined to diffusive kinetics

Cited by 87 publications

References 75 publications

Physicochemical Properties of Nitrogen Doped Carbon Nano‐onions Grown by Flame Pyrolysis from Grapeseed Oil for Use in Supercapacitors

Physicochemical Properties of Nitrogen Doped Carbon Nano‐onions Grown by Flame Pyrolysis from Grapeseed Oil for Use in Supercapacitors

Repurposing N-Doped Grape Marc for the Fabrication of Supercapacitors with Theoretical and Machine Learning Models

Novel Gram‐Scale Synthesis of Carbon Nano‐Onions from Heavy Oil for Supercapacitors

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