Reasonable Construction of Hollow Carbon Spheres with an Adjustable Shell Surface for Supercapacitors

Du, Jiangfeng; Chen, Aibing; Gao, Xueqing; Zhang, Yue; Lv, Haijun

doi:10.1021/acsami.1c21009

Cited by 31 publications

(11 citation statements)

References 43 publications

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“…Thus, among the various hollow carbon structures, HPCS-II possesses appropriate structural features that enhance its supercapacitive performance. 39 The cyclic voltammograms of HPCS-I, HPCS-II, HPCS-III, and HPCS-IV studied at different scan rates are given in the Supporting Information, Figures S7−S10. The voltammograms of all of the samples follow the same pattern: with the increase of scan rate, the area under the curve increases gradually, maintaining a similar rectangular shape.…”

Section: Resultsmentioning

confidence: 99%

Carbon Structures with Hollow Internal Cavity as Charge Storage Materials to Achieve High Energy Density

Pal

Nandi

2023

Energy Fuels

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Hollow porous carbon spheres (HPCS) have been synthesized by using spherical silica nanoparticles (S–SiO 2 ) as templates. S–SiO 2 nanoparticles have been coated first with the polymer of phloroglucinol/1,4-phenylenediamine/formaldehyde (PPF), followed by a second layer of SiO2, and again with PPF as the third layer. After each step of coating, the sample has been pyrolyzed under nitrogen and S–SiO 2 has been removed to obtain HPCS-I, HPCS-II, and HPCS-III, from the first, second, and third coated samples, respectively. The synthetic strategy relies on the use of a hard template to create void spherical cores and space confinement to develop shells of the hollow spheres. All of the materials show a uniform spherical morphology with a hollow inner core generated by the removal of the SiO2 template. The samples have been characterized by thermal analysis, powder X-ray diffraction, nitrogen adsorption/desorption studies, electron microscopy, and X-ray photoelectron spectroscopy. Among the samples, the structural formation of HPCS-II is found to be superior and it is also manifested in its electrochemical properties. While all of the samples exhibit near-rectangular cyclic voltammograms, the specific capacitance of HPCS-II is found to be the highest. Galvanostatic charge/discharge (GCD) studies also support the observation, and the specific capacitance is found to be 592 F·g–1 at a current density of 1 A·g–1, which is retained at 444 F·g–1 even at a very high current density of 100 A·g–1. The major contribution toward such electrochemical behavior is believed to arise from electrical double-layer capacitance (EDLC). HPCS-II is found to be highly stable, retaining 100% of its capacitance value at least up to 5000 GCD cycles. The power density of HPCS-II is nearly thrice the power target value projected by the Partnership for a New Generation of Vehicles (PNGV), and it shows an outstanding energy density value.

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Section: Resultsmentioning

confidence: 99%

Carbon Structures with Hollow Internal Cavity as Charge Storage Materials to Achieve High Energy Density

Pal

Nandi

2023

Energy Fuels

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“…47 Furthermore, doping oxygen and nitrogen elements into the carbon skeleton can alleviate the wettability of the carbon material and offer additional pseudo-capacitance. 50 Therefore, it is evident from the XPS results that the nitrogen atom is structurally infused into the carbon skeleton. The chemical compositions of the yolk−shell carbon nanospheres were further determined by using a CHN elemental analyzer, and the results are shown in Table 1.…”

Section: Resultsmentioning

confidence: 99%

“…The high-resolution O 1s spectra confirmed the presence of an O signal (O–C=O (289.1 eV) and C–O (286.1 eV)) (Figure d) . Furthermore, doping oxygen and nitrogen elements into the carbon skeleton can alleviate the wettability of the carbon material and offer additional pseudo-capacitance . Therefore, it is evident from the XPS results that the nitrogen atom is structurally infused into the carbon skeleton.…”

Section: Resultsmentioning

confidence: 99%

N-Doped Yolk–Shell Carbon Nanospheres with “Carbon Bridges” for Supercapacitors

Zhang

Jiang

Zou

et al. 2023

ACS Appl. Nano Mater.

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N-doping multilocular carbon spheres are beneficial to improving the electrical property due to their unique pore structure and elemental composition; nevertheless, there is a great challenge to fabricate this structure in a facile way. In this work, an N-doping yolk–shell carbon nanosphere with a “carbon bridges” structure was prepared by domain-limited carbonization of RF@SiO2 (RF = resorcinol-formaldehyde resin) with ethylenediamine (EDA) as the nitrogen precursor. The structure of the “carbon bridges” and the carbon shell’s thickness can be adjusted by controlling the thickness of the silica layer, resulting in a change in morphology (from dense nanospheres to yolk–shell nanospheres). The optimized yolk–shell carbon nanospheres (C@C-2 nanospheres) exhibited high N-doping, an abundant micro-mesoporous structure, and an optimum “carbon bridges” structure, contributing to a high-rate capability in a supercapacitor, which was reflected in the energy storage dynamics. Herein, C@C-2 nanospheres, as an electrode material for supercapacitors, presented a reversible specific capacitance of 373.3 F g–1 at 0.5 A g–1 in 2 M KOH and retained a well-advanced capacitance retention capability (95.8%) at 4 A g–1 for more than 10,000 cycles. This work sheds light on an avenue to design high-performance porous carbons for efficient energy storage.

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“…9−12 Nevertheless, the specific capacitance of negative electrodes dominated by activated carbon (AC) with rich microporous frameworks is still insufficient (<300 F g −1 ) in comparison to those of positive materials. 13,14 Such a huge capacity gap between the battery-type and carbon capacitive electrodes inevitably leads to unsatisfactory electrochemical performance for AHSs. In particular, their energy densities are greatly restricted by the carbon-based negative electrodes.…”

Section: Introductionmentioning

confidence: 99%

“…Aqueous supercapacitors have attracted considerable attention in both academia and industrial fields due to their high power density, extremely long cycling life, and intrinsic safety. − In particular, the asymmetric design of aqueous supercapacitors by utilizing different charge storage mechanisms of two electrodes, i.e., aqueous hybrid supercapacitors (AHSs), are considered as promising candidates for efficient energy storage systems, in which the battery-type/pseudocapacitive materials and carbon materials are usually employed as positive and negative electrodes, respectively. − Therefore, it is believed that the overall operating voltage windows ( V ) of devices can be maximized by making full use of the potential difference between two kinds of electrodes in the aqueous electrolyte, thus further delivering high energy density ( E ) according to the equation E = 1/2 CV 2 , where C is specific capacitance . In recent years, considerable research efforts have been devoted to developing various positive electrode materials, such as RuO 2 , Ni(OH) 2 , metal–organic frameworks (MOFs), and conductive polymers, in which a high specific capacitance of more than 1500 F g –1 can be easily obtained. − Nevertheless, the specific capacitance of negative electrodes dominated by activated carbon (AC) with rich microporous frameworks is still insufficient (<300 F g –1 ) in comparison to those of positive materials. , Such a huge capacity gap between the battery-type and carbon capacitive electrodes inevitably leads to unsatisfactory electrochemical performance for AHSs. In particular, their energy densities are greatly restricted by the carbon-based negative electrodes.…”

Section: Introductionmentioning

confidence: 99%

Encapsulation of Redox p-Benzoquinone into Microporous Carbon Frameworks by a Diamine Covalent-Grafted Strategy for Aqueous Hybrid Supercapacitors

Liu

Wang

Che

et al. 2023

ACS Appl. Energy Mater.

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Aqueous hybrid supercapacitors (AHSs) with a wide operating voltage and intrinsic safety are emerging as promising energy storage devices, while their energy densities are still greatly restricted by carbon-based negative electrodes. Developing a high-performance redox system for carbon electrodes is one of the potential strategies to realize the practical utilization of AHSs. Herein, we present a covalent-grafted strategy to encapsulate redox p-benzoquinone (PBQ) into microporous carbon frameworks by using p-phenylenediamine (PPD) as a bridging agent. Both experimental and theoretical analysis reveal that the diamine groups from PPD play a vital role in chemically bonding PBQ with the microporous surfaces of carbon materials, which deliver a great deal of electronic delocalization throughout the redox-active sites and conductive carbon regions. As such, the obtained carbon electrodes grafted by the redox PBQ and PPD species facilitate charge transfer and consequently exhibit excellent charge storage performances. These are highlighted by an extremely high specific capacitance of 377 F g–1 at a current density of 0.5 A g–1 and 276 F g–1 at 100 A g–1 with a superior rate capability of 73%. Impressively, the assembled AHSs based on covalently grafted carbon electrodes (AC-PPD-PBQ) and NiCoAl-layered double hydroxides/carbon nanotubes (NiCoAl-LDH@CNT) demonstrate a maximum energy density of 70.9 W h kg–1 with a wide voltage window of 1.8 V and good cycling stability with 84.4% of initial capacitance after 5000 cycles. This work provides insights into the fabrication of high-performance carbon electrodes by encapsulating redox species into microporous frameworks.

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Reasonable Construction of Hollow Carbon Spheres with an Adjustable Shell Surface for Supercapacitors

Cited by 31 publications

References 43 publications

Carbon Structures with Hollow Internal Cavity as Charge Storage Materials to Achieve High Energy Density

Carbon Structures with Hollow Internal Cavity as Charge Storage Materials to Achieve High Energy Density

N-Doped Yolk–Shell Carbon Nanospheres with “Carbon Bridges” for Supercapacitors

Encapsulation of Redox p-Benzoquinone into Microporous Carbon Frameworks by a Diamine Covalent-Grafted Strategy for Aqueous Hybrid Supercapacitors

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