Graphene for energy conversion and storage in fuel cells and supercapacitors

Choi, Hyun‐Jung; Jung, Sun‐Min; Seo, Jungyun; Chang, Dong Wook; Dai, Liming; Baek, Jong‐Beom

doi:10.1016/j.nanoen.2012.05.001

Cited by 652 publications

(345 citation statements)

References 121 publications

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“…Graphene possesses many extraordinary properties [1,2], with potential applications in numerous scientific and engineering disciplines, including electronic devices, transparent conductive films, mechanical devices, chemical sensors, energy conversion and storage applications, etc [1][2][3][4][5][6].. Electrical, mechanical and optical performances of graphene crucially depend on its structural characteristics, i.e., number of monolayers, presence of sp 3 carbons, defects etc. Normally, the structural properties of nanostructures and, in particular, of grapheme, essentially depend on the assembly pathway.…”

Section: Introductionmentioning

confidence: 99%

Microwave plasmas applied for the synthesis of free standing graphene sheets

Tatarova¹,

Dias²,

Henriques³

et al. 2014

J. Phys. D: Appl. Phys.

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Self-standing graphene sheets were synthesized using microwave plasmas driven by surface waves at 2.45 GHz stimulating frequency and atmospheric pressure. The method is based on injecting ethanol molecules through a microwave argon plasma environment, where decomposition of ethanol molecules takes place. The evolution of the ethanol decomposition was studied in situ by plasma emission spectroscopy. Free gas-phase carbon atoms created in the plasma diffuse into colder zones, both in radial and axial directions, and aggregate into solid carbon nuclei. The main part of the solid carbon is gradually withdrawn from the hot region of the plasma in the outlet plasma stream where nanostructures assemble and grow. Externally forced heating in the assembly zone of the plasma reactor has been applied to engineer the structural qualities of the assembled nanostructures. The synthesized graphene sheets have been analysed by Raman spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy and x-ray photoelectron spectroscopy. The presence of sp 3 carbons is reduced by increasing the gas temperature in the assembly zone of the plasma reactor. As a general trend, the number of mono-layers decreases when the wall temperature increases from 60 to 100 • C. The synthesized graphene sheets are stable and highly ordered.

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Section: Introductionmentioning

confidence: 99%

Microwave plasmas applied for the synthesis of free standing graphene sheets

Tatarova¹,

Dias²,

Henriques³

et al. 2014

J. Phys. D: Appl. Phys.

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“…In many scientific reports graphene oxide (GO) has been used to support Pt nanoparticles, due to oxygen-containing functional groups on both basal planes (epoxy and hydroxyl groups) and edge planes (carbonyl and carboxyl groups). They are usually not single-layer and the presence of oxygen functional groups can act as anchoring sites to attach nanoparticles and enhance the uniform distribution [20,21].…”

Section: Graphenementioning

confidence: 99%

Nitrogen-doped graphene with enhanced oxygen reduction activity produced by pyrolysis of graphene functionalized with imidazole derivatives

Borghei

Azcune

Carrasco

et al. 2014

International Journal of Hydrogen Energy

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Direct methanol fuel cells (DMFC) are great candidates for portable power source applications. However, the sluggish reaction kinetics are key challenges in DMFC technology. The state-of-the-art electrocatalysts are Pt-based catalysts supported on carbon black. However, the high price of Pt, corrosion of carbon support and Pt degradation are the main problems.In this thesis, carbon nanomaterials, namely few-walled carbon nanotubes (FWCNTs) and graphitized nanofibers (GNFs) were used as catalyst supports in the search for stable and durable catalysts. PtRu nanocatalysts with similar particle size and composition were synthesized and deposited on FWCNTs and GNFs. The electrochemical activities for methanol oxidation were compared with that of PtRu-carbon black in acidic conditions. The half-cell electrochemical measurements revealed higher activity with PtRu-GNFs and PtRu-FWCNTs. Later, the electrocatalysts were tested in macro-and micro-DMFC. The results revealed the significant influence of the catalyst support, inomer contect, electrode structure, preparation method, as well as the fuel cell architecture on the performance of a specific electrode material. The results also highlighted the necessity of electrode composition optimization when applying new materials at the electrodes, in order to achieve the best activity and durability for a certain electrocatalyst.A special effort was also done to achieve Pt-free electrocatalysts with high activity for the oxygen reduction reaction (ORR) by introducing nitrogen heteroatoms in carbon nanomaterials, namely FWCNTs and graphite nanoplatelets (GNPs). N-FWCNTs exhibited remarkable electrocatalytic activity for ORR in alkaline media, despite their very low nitrogen content (~0.5 at.%). N-FWCNTs performed on par or better than a commercial Pt-C at the cathode of an alkaline DMFC. The N-GNPs exhibited enhanced electrocatalytic activity for ORR compared to pristine GNPs in alkaline media. The results indicated that N-doped carbon nanomaterials could be promising alternatives to their Pt counterparts to reduce fuel cell costs. However, further investigations are necessary to ascertain the real active sites in order to design more efficient and durable ORR electrocatalysts.Keywords Carbon nanomaterials, PtRu catalysts, nitrogen-doping, direct methanol fuel cell ISBN (printed) 978-952-60-6140-5 ISBN (pdf) 978-952-60-6141-2

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“…Therefore, graphene has been considered an ideal electrode material for supercapacitors [7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Prevention of Graphene Restacking for Performance Boost of Supercapacitors—A Review

Östling

2013

Crystals

107

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Graphene is a promising electrode material for supercapacitors mainly because of its large specific surface area and high conductivity. In practice, however, several fabrication issues need refinement. The restacking of graphene flakes upon being packed into supercapacitor electrodes has become a critical challenge in the full utilization of graphene's large specific surface area to further improve the device performance. In this review, a variety of recent techniques and strategies are overviewed for the prevention of graphene restacking. They have been classified into several categories to improve and facilitate the discussion on the underlying ideas. Based on the overview of the existing techniques, we discuss the trends of future research in the fields.

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Graphene for energy conversion and storage in fuel cells and supercapacitors

Cited by 652 publications

References 121 publications

Microwave plasmas applied for the synthesis of free standing graphene sheets

Microwave plasmas applied for the synthesis of free standing graphene sheets

Nitrogen-doped graphene with enhanced oxygen reduction activity produced by pyrolysis of graphene functionalized with imidazole derivatives

Prevention of Graphene Restacking for Performance Boost of Supercapacitors—A Review

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