Boosting the cyclic stability and supercapacitive performance of graphene hydrogels via excessive nitrogen doping: Experimental and DFT insights

Ahmed, Nashaat; Amer, Aya; Ali, Basant A.; Biby, Ahmed H.; Mesbah, Yasmine I.; Allam, Nageh K.

doi:10.1016/j.susmat.2020.e00206

Cited by 12 publications

(4 citation statements)

References 47 publications

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“…42 Figure 7a displays the cyclic voltammograms of the activated Ni−Mn−O@C//B-MPC device at 5 mV/s, revealing a high specific capacitance of 126 F/g. Note the quasi-rectangular shape at both high and low scan rates (5−100 mV/s), indicating the pseudocapacitive behavior, which can be ascribed to the MnO and NiO oxides encapsulated in the fiber texture 39,58 as well as the existing oxygen−carbon function groups. Besides, Figure 7b demonstrates that the Ni−Mn−O@C//B-MPC device sustains ≈30% of its capacitance at an extremely high scan rate of 100 mV/s.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Binder-Free Electrospun Ni–Mn–O Nanofibers Embedded in Carbon Shells with Ultrahigh Energy and Power Densities for Highly Stable Next-Generation Energy Storage Devices

et al. 2021

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We demonstrate the fabrication of binder-free electrospun nickel− manganese oxides embedded into carbon-shell fibrous electrodes. The morphological and structural properties of the assembled electrode materials were elucidated by high-resolution transmission electron microscopy (HR-TEM), field-emission scanning electron microscopy, and glancing-angle X-ray diffraction. The fibrous structure of the electrodes was retained even after annealing at high temperatures. The X-ray photoelectron spectroscopy and HR-TEM analyses revealed the formation of nickel and manganese oxides in multiple oxidation states (Ni 2+ , Ni 3+ , Mn 2+ , Mn 3+ , and Mn 4+ ) embedded in the carbon shell. The embedded nickel−manganese oxides into the carbon matrix fibrous electrodes exhibit an excellent capacitance (1082 F/g) in 1 M K 2 SO 4 at 1 A/g and possess a high rate capability of 73% at 5 A/g. The high rate capability and capacitance can be attributed to the presence of carbon crosslinked channels, the binder-free nature of the electrodes, and various oxidation states of the Ni−Mn oxides. The asymmetric supercapacitor device constructed of the asfabricated nanofibers and the bio-derived microporous carbon as the positive and negative electrodes, respectively, sustains up to 1.9 V with a high specific capacitance at 1.5 A/g of 108 F/g. The nanofibrous//bio-derived device exhibits an outstanding specific energy of 54.2 W h/kg with a high specific power of 1425 W/kg. Interestingly, the tested device maintains a high capacitive retention of 92% upon cycling over 10,000 charging/discharging cycles.

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Section: ■ Experimental Sectionmentioning

confidence: 99%

Binder-Free Electrospun Ni–Mn–O Nanofibers Embedded in Carbon Shells with Ultrahigh Energy and Power Densities for Highly Stable Next-Generation Energy Storage Devices

et al. 2021

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“…Whereas the strongest peak at 398.48 ± 0.05 eV is ascribed to pyridinic nitrogen, the three other peaks at 399.1 ± 0.05, 400.9 ± 0.05, and 404.1 ± 0.05 eV can be assigned to tertiary nitrogen (N− C), amino nitrogen (N−H), and nitrogen-oxide group, respectively. 27,46 Upon the addition of biocarbon, the pyridinic and tertiary nitrogen content increased by 0.3 and 2.62%, respectively and the nitrogen-oxide and amino nitrogen decreased by ∼0.24% and 2.65%, respectively. The pyridinic and tertiary nitrogen, which have a high electron density and electron donating properties are responsible for pseudocapacitive nature in electrochemical 47 and biocarbon additive increase the contribution of both species.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Highly Stable Supercapacitor Devices Based on Three-Dimensional Bioderived Carbon Encapsulated g-C₃N₄ Nanosheets

Taha

Ghanem

Hamza

et al. 2021

ACS Appl. Energy Mater.

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Owing to the increasing demand for sustainable and ecofriendly energy storage devices such as supercapacitors, it is vital to continuously search for highly stable and cost-effective electrode materials with high energy and power densities. Herein, a 3D/2D metal-free mesoporous composite of graphitic carbon nitride (GCN) and bioderived carbon (Bio-C x ) is investigated as an energy storage electrode material. This composite overcomes the low conductivity and low capacitance limitations of GCN while enjoying its high corrosion resistance, high nitrogen content, and unique 2D structure. The GCN/Bio-C x composite exhibits a fairly wide operating potential window of 1.2 V in 0.5 M H 2 SO 4 aqueous electrolyte with a high capacitance of 300 F/g at 1 A/g. This high performance was ascribed to the huge number of available active sites, large surface area, and the unique 3D/2D structure. The assembled device employing the GCN/ Bio-C x composite as the positive electrode and mesoporous nitrogen-doped carbon (MPNDC) as the negative electrode showed an ultrahigh-energy density of 53.72 Wh/kg and a power density of 900 W/kg. The GCN/Bio-C x //MPNDC device retains ∼100% of its initial capacitance after 13 000 charge/discharge cycles with 100% Columbic efficiency.

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“…Gaussian 16 software with the B3LYP method and the 6-31G (d,p) basis set was used to investigate the electronic structure of different fullerenes. 23 The bandgap energies of the investigated fullerenes (C 60 , C 70 , C 76 , C 84 , and C 100 ) were calculated by subtracting the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). Nanotube modeler, GaussView 6, and GaussSum software were used to visualize and analyze the data.…”

Section: ■ Introductionmentioning

confidence: 99%

C₇₆ Nanospheres/Ni Foam as High-Performance Heterostructured Electrocatalysts for Hydrogen Evolution Reaction: Unveiling the Interfacial Interaction

Hasan

Khedr

Allam

2022

ACS Appl. Nano Mater.

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Fullerenes have emerged as functional catalytic nanomaterials in a plethora of applications, mainly due to their distinctive electronic structures. Therefore, we investigated the electronic structures of different fullerenes (C 60 , C 70 , C 76 , C 84 , and C 100 ) using density functional theory (DFT) calculations to identify the most suitable candidate as a hydrogen evolution reaction (HER) catalyst. The calculations showed that C 76 exhibits the most convenient electronic structure suitable for HER. Consequently, the synergy between C 76 nanospheres and nickel foam substrate as a highly efficient HER catalyst has been demonstrated and discussed. The results showed that C 76 nanospheres−Ni foam exhibits a superior catalytic activity with an overpotential of 20 mV vs RHE at −10 mA cm −2 , which is almost the same as the benchmark Pt/C catalyst. The calculated free energy and band structure revealed a significant increase in the electron density at the C 76 /Ni foam interface, indicating the synergy between C 76 nanospheres and Ni. Moreover, the exchange current density (J 0 ), charge transfer coefficient (α), and mass activity (MA) were determined to elucidate the kinetics of the HER upon loading the Ni foam with different masses of C 76 . The electrodes containing 0.48 and 0.53 mg of C 76 exhibited high α and J 0 , revealing very fast HER kinetics on their surfaces. This observed drastic increase in J 0 is accompanied by a reduction in the activation barrier, which is in agreement with the DFT results.

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Boosting the cyclic stability and supercapacitive performance of graphene hydrogels via excessive nitrogen doping: Experimental and DFT insights

Cited by 12 publications

References 47 publications

Binder-Free Electrospun Ni–Mn–O Nanofibers Embedded in Carbon Shells with Ultrahigh Energy and Power Densities for Highly Stable Next-Generation Energy Storage Devices

Binder-Free Electrospun Ni–Mn–O Nanofibers Embedded in Carbon Shells with Ultrahigh Energy and Power Densities for Highly Stable Next-Generation Energy Storage Devices

Highly Stable Supercapacitor Devices Based on Three-Dimensional Bioderived Carbon Encapsulated g-C₃N₄ Nanosheets

C₇₆ Nanospheres/Ni Foam as High-Performance Heterostructured Electrocatalysts for Hydrogen Evolution Reaction: Unveiling the Interfacial Interaction

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Boosting the cyclic stability and supercapacitive performance of graphene hydrogels via excessive nitrogen doping: Experimental and DFT insights

Cited by 12 publications

References 47 publications

Binder-Free Electrospun Ni–Mn–O Nanofibers Embedded in Carbon Shells with Ultrahigh Energy and Power Densities for Highly Stable Next-Generation Energy Storage Devices

Binder-Free Electrospun Ni–Mn–O Nanofibers Embedded in Carbon Shells with Ultrahigh Energy and Power Densities for Highly Stable Next-Generation Energy Storage Devices

Highly Stable Supercapacitor Devices Based on Three-Dimensional Bioderived Carbon Encapsulated g-C3N4 Nanosheets

C76 Nanospheres/Ni Foam as High-Performance Heterostructured Electrocatalysts for Hydrogen Evolution Reaction: Unveiling the Interfacial Interaction

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Highly Stable Supercapacitor Devices Based on Three-Dimensional Bioderived Carbon Encapsulated g-C₃N₄ Nanosheets

C₇₆ Nanospheres/Ni Foam as High-Performance Heterostructured Electrocatalysts for Hydrogen Evolution Reaction: Unveiling the Interfacial Interaction