Towards high-efficient microsupercapacitors based on reduced graphene oxide with optimized reduction degree

Rodríguez-Mata, Vanesa; Hernández‐Ferrer, Javier; Carrera, Clara; Benito, Ana M.; Maser, Wolfgang K.; García‐Bordejé, Enrique

doi:10.1016/j.ensm.2019.09.012

Cited by 21 publications

(13 citation statements)

References 43 publications

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“…The use of aqueous solutions of nitrogen-containing compounds in the hydrothermal process makes it possible to functionalize the carbon surface with nitrogen. For example, the wet chemical route is a very explicit and effective approach to fabricate N-doped graphene through the reactions of oxygenated graphite with thiourea [75], urea [76,77], sodium azide [78] and ammonia [79]. The hydrothermal reaction of ammonia solution with the carbon material is analogous to that in pure water.…”

Section: Discussionmentioning

confidence: 99%

“…The hydrothermal treatment of graphite oxide in an aqueous solution of urea yielded N-doped graphene with a high nitrogen content (up to 10 at%), which had a superior specific capacitance of 326 F g −1 in 6M KOH electrolyte at a current density of 0.2 A g −1 [76]. The hydrothermal treatment of an aqueous dispersion of graphite oxide by NH 3 solution (0.01 vol.%) resulted in the synthesis of N-doped graphene aerogel with a nitrogen content of 6 at.% [79]. The aerogel, which underwent the hydrothermal treatment time for 45 min, had the highest gravimetric capacitance of 400 F g −1 at 50 A g −1 in 1M Na 2 SO 4 electrolyte.…”

Section: Discussionmentioning

confidence: 99%

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Hydrothermal Activation of Porous Nitrogen-Doped Carbon Materials for Electrochemical Capacitors and Sodium-Ion Batteries

et al. 2020

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Highly porous nitrogen-doped carbon nanomaterials have distinct advantages in energy storage and conversion technologies. In the present work, hydrothermal treatments in water or ammonia solution were used for modification of mesoporous nitrogen-doped graphitic carbon, synthesized by deposition of acetonitrile vapors on the pyrolysis products of calcium tartrate. Morphology, composition, and textural characteristics of the original and activated materials were studied by transmission electron microscopy, X-ray photoelectron spectroscopy, near-edge X-ray absorption fine structure spectroscopy, infrared spectroscopy, and nitrogen gas adsorption method. Both treatments resulted in a slight increase in specific surface area and volume of micropores and small mesopores due to the etching of carbon surface. Compared to the solely aqueous medium, activation with ammonia led to stronger destruction of the graphitic shells, the formation of larger micropores (1.4 nm vs 0.6 nm), a higher concentration of carbonyl groups, and the addition of nitrogen-containing groups. The tests of nitrogen-doped carbon materials as electrodes in 1M H2SO4 electrolyte and sodium-ion batteries showed improvement of electrochemical performance after hydrothermal treatments especially when ammonia was used. The activation method developed in this work is hopeful to open up a new route of designing porous nitrogen-doped carbon materials for electrochemical applications.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Hydrothermal Activation of Porous Nitrogen-Doped Carbon Materials for Electrochemical Capacitors and Sodium-Ion Batteries

et al. 2020

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“…Some of the working conditions led to porous and light graphene-based aerogels [26,28]. We have taken advantage of the possibilities granted by unidirectional freezing, followed by lyophilization, which are able to create an anisotropic internal microstructure composed of parallel channels, with critical applications in energy and environmental remediation [28,31,32]. In the present case, hydrogels were prepared under specific conditions and subjected to hydrothermal treatment with the ternary GO/NCC/CNT system in water (see Section 3.1 and Figure 10), and when subjected to unidirectional freezing prior to lyophilization, they also presented an anisotropic porous microstructure.…”

Section: Properties Of Hydrogel-derived Aerogelsmentioning

confidence: 99%

Waterborne Graphene- and Nanocellulose-Based Inks for Functional Conductive Films and 3D Structures

et al. 2021

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In the vast field of conductive inks, graphene-based nanomaterials, including chemical derivatives such as graphene oxide as well as carbon nanotubes, offer important advantages as per their excellent physical properties. However, inks filled with carbon nanostructures are usually based on toxic and contaminating organic solvents or surfactants, posing serious health and environmental risks. Water is the most desirable medium for any envisioned application, thus, in this context, nanocellulose, an emerging nanomaterial, enables the dispersion of carbon nanomaterials in aqueous media within a sustainable and environmentally friendly scenario. In this work, we present the development of water-based inks made of a ternary system (graphene oxide, carbon nanotubes and nanocellulose) employing an autoclave method. Upon controlling the experimental variables, low-viscosity inks, high-viscosity pastes or self-standing hydrogels can be obtained in a tailored way. The resulting inks and pastes are further processed by spray- or rod-coating technologies into conductive films, and the hydrogels can be turned into aerogels by freeze-drying. The film properties, with respect to electrical surface resistance, surface morphology and robustness, present favorable opportunities as metal-free conductive layers in liquid-phase processed electronic device structures.

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“…In graphene-CNT hybrid, the CNTs form a conductive framework to which the graphene flakes adhere, significantly improving the overall conductivity with respect to CNT alone due to an increase in tunnelling efficiency [30,31]. In our previous work, hydrothermal treatment of GO dispersion led to porous reduce graphene oxide hydrogel and subsequently aerogel after freeze drying [32,33]. In the literature, there are a few examples of the preparation of graphene-CNT used for supercapacitors [29] and metal-free ORR catalysts [34].…”

Section: Introductionmentioning

confidence: 99%

Hybrids of Reduced Graphene Oxide Aerogel and CNT for Electrochemical O2 Reduction

Hernández‐Ferrer¹,

Benito²,

Maser³

et al. 2021

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Carbon nanotubes (CNTs), graphene aerogels (GAs), and their hybrid (CNT-GA) prepared by hydrothermal treatment were tested in the electrocatalytic oxygen reduction reaction (ORR). The importance of porous structure derived from the combination of mesoporosity coming from CNTs with macroporosity stemming from GAs was evidenced because the hybrid carbon material exhibited synergistic performance in terms of kinetic current and onset potential. Different electrocatalysts were prepared based on these hybrids doped with nitrogen using different precursors and also supporting Fe nanoparticles. N-doped carbon hybrids showed higher electrocatalytic activity than their undoped counterparts. Nevertheless, both doped and undoped materials provided a mixed two and four electron reduction. On the other hand, the addition of a Fe precursor and phenanthroline to the CNT-GA allowed preparing an N-doped hybrid containing Fe nanoparticles which favored the 4-electron oxygen reduction to water, thus being an excellent candidate as a structured cathode in fuel cells.

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Towards high-efficient microsupercapacitors based on reduced graphene oxide with optimized reduction degree

Cited by 21 publications

References 43 publications

Hydrothermal Activation of Porous Nitrogen-Doped Carbon Materials for Electrochemical Capacitors and Sodium-Ion Batteries

Hydrothermal Activation of Porous Nitrogen-Doped Carbon Materials for Electrochemical Capacitors and Sodium-Ion Batteries

Waterborne Graphene- and Nanocellulose-Based Inks for Functional Conductive Films and 3D Structures

Hybrids of Reduced Graphene Oxide Aerogel and CNT for Electrochemical O2 Reduction

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