Powder, Paper and Foam of Few‐Layer Graphene Prepared in High Yield by Electrochemical Intercalation Exfoliation of Expanded Graphite

Wu, Liqiong; Li, Weiwei; Li, Peng; Liao, Shutian; Qiu, Shengqiang; Chen, Ming-Liang; Guo, Yikun; Qi, Li; Zhu, Chao; Liu, Liwei

doi:10.1002/smll.201302730

Cited by 130 publications

(105 citation statements)

References 64 publications

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“…This value is much higher than those of CCG papers [43][44][45] and exfoliated graphite papers, [ 46,47 ] mainly due to the perfect crystalline graphitic structure of NSGF. The electrical conductivity of NSGF is a little lower than that of the reported annealed graphene paper, [ 48 ] CVD graphene [ 49 ] and the GFL precursor (1065 S cm −1 ) (Table S3, Supporting Information).…”

Section: The Electrocatalytic Performances For Oermentioning

confidence: 71%

Nitrogen and Sulfur Codoped Graphite Foam as a Self‐Supported Metal‐Free Electrocatalytic Electrode for Water Oxidation

Zhang

et al. 2015

Advanced Energy Materials

160

110

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positively charged. They can adsorb OH − ions with charge transfer to decrease the activation energy of OER, and support the recombination of OER intermediates (e.g., O 2− and O 2 2− ) to form oxygen gas during OER process. [ 17,21,22 ] Furthermore, the nitrogen species (e.g., pyridinic N atoms) can also participate in the electrocatalytic reaction. [ 20 ] Consequently, the carbon materials doped with N atoms or containing oxygenated groups can remarkably accelerate OER process, and they are expected to be effective substitutions of metal catalysts.Conversely, the reported OER electrocatalysts usually were powders; thus they have to be anchored onto glassy carbon electrodes or other conductive planar electrodes (e.g., carbon cloth) with polymeric binders for practical applications. Unfortunately, in these cases, the surfaces of electrocatalysts were partly inaccessible to reactants, and the 2D substrates are not suitable for desorption of O 2 bubbles, weakening the activity and restricting the recovery of active sites of OER catalysts. To overcome these problems, 3D structured electrodes with nickel foams or porous carbon hydrogel fi lms have been developed to immobilize catalysts. [ 21,[23][24][25][26] The high macroporosity of nickel foam can greatly increase the accessible specifi c surface areas of loaded catalysts, and facilitate the removal of gases. [ 23 ] However, the intrinsic instability of nickel decreased the long-term durability of these catalysts. Furthermore, the weak contacts between catalysts and nickel substrate frequently led to the releasing of catalysts during oxygen generation reaction. [ 21 ] The OER electrocatalysts with carbon hydrogel fi lms were mainly explored by Qiao's group. [ 21,[24][25][26] These 3D self-supported frameworks avoid using current collectors and polymeric binders (e.g., nafi on or polytetrafl uoroethylene), and the catalysts exhibited excellent activities. However, the hydrogel fi lms were prepared from chemical converted graphene (CCG) sheets by fi ltration. The preparation of CCG sheets usually involves a multistep complicated process, and using large amounts of acids, oxidants, and reducing agents. Moreover, the as-obtained CCG fi lms (without adding conductive additives or annealing treatment) have relatively low conductivities and brittle mechanical properties, possibly resulting in high overpotential and poor long-term stability.Commercial graphite foils (GFLs) are usually made of exfoliated graphite fl akes. They are cheap, available in large areas, fl exible, highly conductive, and thermally stable. Furthermore, they compose of nearly only carbon atoms without anyThe oxidation of water to produce oxygen gas is related to a variety of energy storage systems. Thus, the development of effi cient, cheap, durable, and scalable electrocatalysts for oxygen evolution reaction (OER) is of great importance. Here, a high-performance OER catalyst, nitrogen and sulfur codoped graphite foam (NSGF) is reported. This NSGF is prepared from commercial graphite foil and directly...

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Section: The Electrocatalytic Performances For Oermentioning

confidence: 71%

Nitrogen and Sulfur Codoped Graphite Foam as a Self‐Supported Metal‐Free Electrocatalytic Electrode for Water Oxidation

Zhang

et al. 2015

Advanced Energy Materials

160

110

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“…In this respect, EEG has been applied in various related applications such as easyto-prepare graphene papers [ 49,61,62 ] as well as the more sophisticated transparent conductive (TC) fi lms. In 2013 a simple spray-coating process was used to fabricate transparent electrodes with a sheet resistance of around 10 kΩ ᮀ −1 and 60% transmittance [ 63 ] and just recently a self-assembled graphene fi lm with a resistance of 21.8 kΩ ᮀ −1 at over 95% transparency has been reported; this value was further improved to 13.5 kΩ ᮀ −1 by doping with AuCl 3 .…”

Section: Research Newsmentioning

confidence: 99%

“…As an alternative to these approaches pristine graphene has been used to create 3D porous structures such as aerogels [ 48 ] and foams. [ 36,49 ] Furthermore, electrochemical exfoliation has been facilitated as a surface treatment for graphitic fi brous networks and graphite foils; here the EEG sheets are only partially exfoliated whereas the graphene source itself remains structurally intact, providing support for the exfoliated material. [ 27,50 ] Another promising fi eld is the use of graphene as an anode material in lithium ion batteries.…”

Section: The Application Of Exfoliated Graphenementioning

confidence: 99%

New‐Generation Graphene from Electrochemical Approaches: Production and Applications

et al. 2016

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Extensive research suggests a bright future for the graphene market. However, for a long time there has been a huge gap between laboratory-scale research and commercial application due to the challenging task of reproducible bulk production of high-quality graphene at low cost. Electrochemical exfoliation of graphite has emerged as a promising wet chemical method with advantages such as upscalability, solution processability and eco-friendliness. Recent progress in the electrochemical exfoliation of graphite and prospects for the application of exfoliated graphene, mainly in the fields of composites, electronics, energy storage and conversion are discussed.

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“…Polypyrrole (PPy) is one of the most widely used CPs due to its good conductivity, low cost and high charge storage capability [8,18]. Flexible electrodes based on graphene/PPy composites provide a high gravimetric capacitance ranging from 92 to 345 F g -1 [19][20][21] and an areal capacitance in the range of 152 to 175 mF cm -2 [22,23].…”

Section: Introductionmentioning

confidence: 99%

A Free-standing Graphene-Polypyrrole Hybrid Paper via Electropolymerization with an Enhanced Areal Capacitance

Shu

Wang

Zhao

et al. 2016

Electrochimica Acta

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Here we developed a free-standing reduced graphene oxide (rGO)-polypyrrole (PPy) hybrid paper via electropolymerization on a paper-like graphene gel. This flexible hybrid paper displayed a uniform layered structure with PPy coated onto the graphene layers. A high areal mass of 2.7 mg cm−2 could be obtained. It delivered a greatly enhanced areal capacitance of 440 mF cm−2 at 0.5 A g−1, in contrast to that 151∼198.5 mF cm−2 previously reported for graphene paper or polypyrrole-graphene paper. It can retain ∼81% of the initial capacitance at a high current density of 6 A g−1. The combined high flexibility with outstanding electrochemical performance, makes such novel hybrid paper a promising electrode for flexible supercapacitors. Disciplines Engineering | Physical Sciences and Mathematics Publication DetailsShu, K., Wang, C., Zhao, C., Ge, Y. & Wallace, G. G. (2016). A free-standing graphene-polypyrrole hybrid paper via electropolymerization with an enhanced areal capacitance. Electrochimica Acta, 212 561-571. AbstractHere we developed a free-standing reduced graphene oxide (rGO)-polypyrrole (PPy) hybrid paper via electropolymerization on a paper-like graphene gel. This flexible hybrid paper displayed a uniform layered structure with PPy coated onto the graphene layers. A high areal mass of 2.7 mg cm -2 could be obtained. It delivered a greatly enhanced areal capacitance of 440 mF cm -2 at 0.5 A g -1 , in contrast to that 151~198.5 mF cm -2 previously reported for graphene paper or polypyrrole-graphene paper. It can retain ~81% of the initial capacitance at a high current density of 6 A g -1 . The combined high flexibility with outstanding electrochemical performance, makes such novel hybrid paper a promising electrode for flexible supercapacitors.

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Powder, Paper and Foam of Few‐Layer Graphene Prepared in High Yield by Electrochemical Intercalation Exfoliation of Expanded Graphite

Cited by 130 publications

References 64 publications

Nitrogen and Sulfur Codoped Graphite Foam as a Self‐Supported Metal‐Free Electrocatalytic Electrode for Water Oxidation

Nitrogen and Sulfur Codoped Graphite Foam as a Self‐Supported Metal‐Free Electrocatalytic Electrode for Water Oxidation

New‐Generation Graphene from Electrochemical Approaches: Production and Applications

A Free-standing Graphene-Polypyrrole Hybrid Paper via Electropolymerization with an Enhanced Areal Capacitance

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