WO2012109665A1 - Composites de graphène nano-structurés à surface élevée et dispositifs capacitifs les intégrant - Google Patents

Composites de graphène nano-structurés à surface élevée et dispositifs capacitifs les intégrant Download PDF

Info

Publication number
WO2012109665A1
WO2012109665A1 PCT/US2012/024894 US2012024894W WO2012109665A1 WO 2012109665 A1 WO2012109665 A1 WO 2012109665A1 US 2012024894 W US2012024894 W US 2012024894W WO 2012109665 A1 WO2012109665 A1 WO 2012109665A1
Authority
WO
WIPO (PCT)
Prior art keywords
graphene
sheets
composite material
surface area
particles
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2012/024894
Other languages
English (en)
Inventor
Jian Xie
Meixian WANG
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Indiana University Research and Technology Corp
Original Assignee
Indiana University Research and Technology Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Indiana University Research and Technology Corp filed Critical Indiana University Research and Technology Corp
Publication of WO2012109665A1 publication Critical patent/WO2012109665A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
    • H01M8/0606—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants
    • H01M8/065—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants by dissolution of metals or alloys; by dehydriding metallic substances
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/26—Electrodes characterised by their structure, e.g. multi-layered, porosity or surface features
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H01G11/32—Carbon-based
    • H01G11/36—Nanostructures, e.g. nanofibres, nanotubes or fullerenes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material
    • H01M4/9075—Catalytic material supported on carriers, e.g. powder carriers
    • H01M4/9083—Catalytic material supported on carriers, e.g. powder carriers on carbon or graphite
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Definitions

  • the novel technology relates generally to materials science, and, more particularly, to a high surface area graphene composite material.
  • Graphene a single-atom-thick sheet consisting of sp 2 hybridized carbon atoms arrayed in a honeycomb pattern, is the building block of graphitic carbons.
  • Graphene may be viewed as an individual atomic plane of the graphite structure.
  • Graphene as a two-dimensional nanosheet has attracted increasing interest due to its unique properties of high in-plane electronic conductivity, high tensile modulus, and high surface area, which make graphene an attractive candidate for applications in electronic devices and composite materials.
  • graphene may be used as a gas adsorbant, ultracapacitor material, or a supporting material for developing novel heterogeneous catalysts with enhanced catalytic activity.
  • Graphene may be produced by any one of several methods, including the straightforward exfoliation technique of manually peeling off of the top surface of small mesas of pyrolytic graphite, chemical vapor deposition on metal surfaces, epitaxial growth on electrically insulating surfaces, such as SiC, and the like.
  • Anchoring nanoparticles on the graphene surface before the GS's aggregation is one effective way to keep the GS's high surface area.
  • the deposition of Pt nanoparticles on a graphene surface before drying has been shown to increase the surface area of the composite from 44 m 2 /g to 862 m 2 /g with the anchoring of the Pt nanoparticles on the surface.
  • Graphene polyoxometalate nanoparticle composites have been observed to yield a graphene surface area of about 680 m 2 /g.
  • Graphene sheet/Ru0 2 composites have been observed with increased surface area increases from 108 m 2 /g to 281 m 2 /g.
  • FIG. 1 is a schematic illustration of the graphene sheet (GS) and the graphene sheet nanocarbon composites (GSNC) preparation process.
  • FIG. 2 graphically illustrates nitrogen adsorption and desorption of the as- prepared GNCs with different nanocarbon content.
  • FIG. 3A illustrates TEM images of the as-prepared GSNCs from pure GSs.
  • FIG. 3B illustrates TEM images of the as-prepared GSNCs with 1%
  • nanocarbon content and a surface area of 1256 m 2 /g.
  • FIG. 3C illustrates TEM images of the as-prepared GSNCs with functionalized nanocarbons.
  • FIG. 3D illustrates TEM images of the as-prepared GSNCs with 1%
  • nanocarbon content and a surface area of 1256 m 2 /g.
  • FIG. 4A presents SEM images of the pure GSs.
  • FIG. 4B presents SEM images of GSNCs with a 1% nanocarbon content and a surface area of 1256 m 2 /g after drying.
  • FIG. 5A graphically illustrates CV curves of the as-prepared GSNCs with a surface area of 1256 m 2 /g, measured at potential intervals from -0.2 to 0.8 V (vs. SHE) in 1 M H 2 S0 4 .
  • FIG. 5B graphically illustrates the capacitance of the GSNCs with different nanocarbon content as the function of current density.
  • FIG. 6 schematically illustrates Pt nanoparticle etching process on the surface of graphene sheets, according to another embodiment of the present novel technology.
  • FIG. 7 A is a first atomic resolution electron micrographs showing the dynamic etching of graphene sheets by Pt nanoparticles and the resulting trenches left behind in the graphene according to the embodiment of FIG. 6.
  • FIG. 7B is a second atomic resolution electron micrographs showing the dynamic etching of graphene sheets by Pt nanoparticles and the resulting trenches left behind in the graphene according to the embodiment of FIG. 7 A.
  • FIG. 7C is a third atomic resolution electron micrographs showing the dynamic etching of graphene sheets by Pt nanoparticles and the resulting trenches left behind in the graphene according to the embodiment of FIG. 7A.
  • FIG. 7D is a fourth atomic resolution electron micrographs showing the dynamic etching of graphene sheets by Pt nanoparticles and the resulting tortured path left behind in the graphene according to the embodiment of FIG. 6.
  • FIG. 7E is a fifth atomic resolution electron micrographs showing the dynamic etching of graphene sheets by Pt nanoparticles and the resulting etch path left behind in the graphene according to the embodiment of FIG. 7D.
  • FIG. 7F is a sixth atomic resolution electron micrographs showing the dynamic etching of graphene sheets by Pt nanoparticles and the resulting etch path left behind in the graphene according to the embodiment of FIG. 7D.
  • FIG. 8A is an electron micrograph of pristine graphene.
  • FIG. 8B is an electron micrograph of Pt nanoparticles etched graphene according to the embodiment of FIG. 6.
  • FIG. 9 graphically illustrates the XPS spectra of graphene before and after Pt nanoparticulate etching, according to the embodiment of FIG. 6.
  • FIG. 10A graphically illustrates the N 2 adsorption isotherms and C0 2 capture properties of graphene composites for graphene, Pt/Graphene, and Pt/Graphene 800 °C at 77 K. P/P°, relative pressure; STP, standard temperature and pressure.
  • FIG. 10B graphically illustrates the N 2 adsorption isotherms and C0 2 capture properties of graphene composites for graphene, Pt/Graphene, and Pt/Graphene 800 °C at 273 K; filled and open symbols represent adsorption and desorption branches, respectively.
  • FIG. 11 is a schematic illustration of a supercapacitor using electrodes made from the embodiment of FIG. 1.
  • graphene sheets 10 were prepared by the exfoliation of graphite oxide (a layered material consisting of hydrophilic oxygenated graphene sheets with oxygen functional groups on their basal planes and edges), such as in water to yield a colloidal suspension of almost entirely individual graphene sheets 10.
  • Nanosized carbon particles 15, typically carbon black particles 15, were functionalized with hydrophilic groups, such as -SO3H (i.e., bisulfate or hydrogen sulfite), and the GSNCs 20 were prepared with different loadings of the
  • functionalized carbon black particles 25 by simultaneous chemical reduction of both the graphene oxides 30 and the functionalized carbon black particles 25 while in solution.
  • Functionalization is the addition of functional groups onto the surface of a material by chemical synthesis methods or the like, and the functional group added can be subjected to ordinary synthesis methods to attach virtually any kind of compound onto the material's surface.
  • the specific surface area of the composites 20 was 1256 m 2 /g, and a maximum specific capacitance of 240 F/g was observed at a current density of ⁇ /g.
  • graphene sheet composite-based capacitors using this composite material 20 for the electrodes exhibited enhanced rate capability, the maximum sustainable continuous or pulsed current output.
  • the above improved electrochemical performance of the GSNCs 20 is a product of their high surface area and high electronic conductivity of the GSs 10.
  • carbon nanoparticles 15 discussed herein are specifically carbon black, other allotropes of carbon may be selected.
  • Amorphous carbon, glass carbon, coke, carbon graphitized to various degrees of graphitization, diamondlike carbon, and diamond may also be selected, with the electrical and physical properties of the resulting composite material 20 varying as a result.
  • the GSs 10 were obtained by in situ chemical reduction of exfoliated graphene oxides 30.
  • the construction of the GSNCs involved the following steps: first, exfoliation 40 of graphite oxides, then, mixing 45 the graphene oxide sheets 30 and functionalized nanocarbons 25, and finally, chemical reduction 50 of the mixture.
  • the nanocarbons 15 were functionalized 55 by the dizonium reaction, and the nanocarbons 25 are highly hydrophilic after functionalization 55.
  • Graphene oxide sheets 30 exist in the liquid dispersion 60. After reduction 50 of the compound 20 in its solid state, the graphene sheets 10 aggregate 65 and stack back into a layer structure like graphite.
  • Graphene oxide sheets 30 and carbon nanoparticles 25 exist together in dispersion 60; in the solid state the nanocarbons 25 serve as spacers, preventing the graphene sheets 10 from restacking back to the graphite structure, and thus make the graphene sheet 10 accessible on both sides and allowing access to the high surface area graphene composite 20.
  • the well-dispersed graphene oxide sheets 30 and the functionalized nanocarbons 25 were reduced simultaneously and the functionalized nanocarbon particles 25 became anchored 75 to the graphene sheets 10.
  • the solid composites 20 float on the surface of the transparent liquid phase of the dispersion 60.
  • the resultant graphene sheets 10 with attached functionalized nanocarbons 25 aggregated together to yield the GSNCs 20 upon drying.
  • the nanocarbons 15 were functionalized 55 by diazonium reactions as shown in FIG. 1A.
  • the hydrophilic -SO3H functional group was grafted onto the surface of the nanocarbons 15.
  • the nanocarbons 25 can disperse well in the water even if left for several months.
  • the two materials were able to be easily mixed and formed uniform dispersion 60.
  • the in-situ-formed composites 20 have more of a rich porous structure and large available surface area for the charge- storage process than those obtained by drying the pure graphene sheets 10, in which the restacking of the graphene sheets 10 inevitably occurs.
  • the nitrogen-adsorption and -desorption isotherms of the as-prepared GSs 10 with different nanocarbon content exhibited type IV characteristics (FIG. 2), which are indicative of the presence of relatively large pores in the composites 20.
  • type IV characteristics FIG. 2
  • BET Brunauer-Emmett-Teller
  • the BET-specific surface area of the composites 20 with nanocarbon content of lwt.% reached as high as 1256 m 2 /g, which is much higher than that of the nanocarbons 25 (790 m 2 /g) and the pure GS 10 (77 m 2 /g).
  • the BET-specific surface area of the composites 20 with additional nanocarbon material 25 was observed to be up to 1875 m 2 /g, and values as high as 2000, 2100 and approaching the theoretical maximum are expected.
  • the large specific surface area suggests that the introduction of nanocarbon particles 25 between 2D graphene sheets 10 effectively limits the face-to-face stacking from about forty layers of graphene sheets 10 per stack to about two layers of graphene sheets 10 per stack when compared with that of dried pure GS 80.
  • FIG. 3A shows that the pure GSs 80 prepared by chemical reduction 50 were transparent with some wrinkles visible under TEM.
  • the morphology of functionalized nanocarbons 25 can be seen in Figure 3B, which shows that the functionalized nanocarbon particles 25 were in the range of 5-30 nm, and that they tended to spontaneously agglomerate together to form large particles.
  • the structure of the GSNCs 20 is shown in FIG.
  • the GSs 10 in the composites 20 were almost transparent, which suggests that the GSs 10 were well separated by the nanocarbon particles 25.
  • the number of layers of graphene sheets 10 in the composites 20 was lower (typically about two layers of GS 10, as suggested by BET data).
  • the above observation also demonstrates the strong interactions/bonding between the nanocarbon carbon particles 25 and the graphene sheet 10 surface.
  • the SEM images also clearly show the difference between the pure GS agglomerations 80 and the GSNCs 20.
  • the pure GSs 10 after drying tended to restack and form solid particles 80 (FIG. 4A).
  • the layered structure can be seen clearly for GSNCs 20, as the small nanocarbon particles 25 are highly dispersed on the graphene sheet 10 surfaces and served as spacers to prevent the graphene sheets 10 from restacking, which is consistent with the observed increased surface area of the graphene sheet/nanocarbon composites 20.
  • GS agglomerates 80 have been used as electrodes for
  • supercapacitors for example, chemically modified GSs electrode active materials in supercapacitors have been found to exhibit a specific capacitance of 135 F/g and 99F/g in aqueous KOH and organic electrolytes, respectively.
  • GS specimens 80 having a measured surface area of 534 m 2 /g have exhibited a capacitance of 150 F/g under the specific current 0.1 A/g.
  • the composite 20 Based on the structure of the GSNCs material 20, the composite 20 likewise is expected to have good electron conductivity, low diffusion resistance to protons/cations, easy electrolyte penetration, and high electroactive areas.
  • Such composites 20 are promising candidates for electrode active materials for supercapacitors 100, yielding high performance energy storage devices.
  • the properties of these GSNCs 20 were measured using cyclic voltammetry (CV) and galvanostatic charge/discharge.
  • the galvanostatic charge/discharge was used to calculate the specific capacitance of the GSNCs 20.
  • the CV curves (FIG. 5A) were nearly rectangular in shape, indicating a good charge propagation within the electrode.
  • the CV curve shape and the specific capacitance significantly degraded as the voltage scan rate increased.
  • the GSNCAs 100 base electrode 105 remained a rectangular shape with little variance, even at a scan rate of 200 mv/s (FIG. 5).
  • GSNCs 20 with a surface area of 1256 m 2 /g exhibited the maximum capacitance of 218 F/g at a current density of 5A/g compared with pure graphene materials 80 with a capacitance of 46 F/g at the same current density, indicating that the unique structure of the novel GSNCs 20 facilitated the rapid transport of the electrolyte ions and electrons throughout the electrode 105.
  • the simple process for preparing high surface area GSs 20 by simultaneously reducing the graphene oxide sheets 30 and the functionalized nanocarbons 25 is more particularly described below.
  • This method is easily scaled up for the mass- production of high surface area graphenes 20.
  • the nanocarbon particles 25 are generally dispersed uniformly on the surface of the graphene sheets 10, serving as spacers between graphene sheets 10, and preventing the restacking of the GSs 10 after drying or removal of the solvent. Consequently, the GSNC surface area has been observed as high as 1875 m 2 /g.
  • the unique structure of the GSNCs 20 facilitated the high-rate transportation of electrolyte ions and electrons throughout the electrode 105, resulting in the excellent electrochemical properties.
  • the supercapacitor 100 based on the GSNCs 20 exhibited a specific capacitance of nearly 400 F/g at a current density of ⁇ /g in a 1M H2SO4 solution.
  • the specific capacitance increased with the increase of the composite surface areas.
  • the new high surface area GS material 20 is also useful as a sorbent for hydrogen storage, as a catalyst support for fuel cells, and as a component for other clean energy devices.
  • nanocarbons GO 30 was synthesized from natural graphite powder (325 mesh) by the modified Hummer method. The GO 30 was then suspended 110 in water to yield an opaque dispersion 60, which was subjected to separation by centrifuge (five times) to completely remove residual salts and acids. The purified GO 30 was then dispersed 120 in purified water (0.5 mg/mL). Exfoliation 40 of the GO 30 was achieved by ultrasonication of the dispersion 60 using an ultrasonic bath. During the composite preparation process, the number of single layers in the GSs 30 as a precursor are typically controlled to be as small as possible.
  • Graphite oxide is a layered material consisting of hydrophilic oxygenated GSs (graphene oxides) 30 bearing oxygen functional groups in their basal planes and edges. Under
  • graphite oxides can undergo complete exfoliation in water, yielding colloidal suspensions 60 wherein the suspended material is composed almost entirely of individual graphene oxide sheets 30.
  • the EC300 carbon blacks 15 were modified with an -SO3H grafted layer in an aqueous medium by spontaneous reduction 50 of the corresponding in situ generated diazonium cation.
  • the modification of EC300 carbon blacks 15 was prepared with a large excess of in s tu-generated diazonium cations.
  • 2 g of EC300 carbon blacks 15 were placed in a 0.5 M HC1 solution 125 containing 3.5 g of sulfonic acid. The solution 125 was vigorously stirred for thirty minutes before sodium nitrite was added.
  • Synthesis of the GSNCs GSNCs 20 with different nanocarbon content were prepared by simultaneously reducing 50 the mixture of the graphene oxide sheets 30 and the highly hydrophilic nanocarbons 25.
  • Graphene oxide sheets 30 dispersed in water were mixed with the nanocarbons 25.
  • the mixture was stirred for thirty minutes and then subjected to ultrasonication for one hour at room temperature.
  • a hydrazine solution was added into the mixture and the mixture was stirred and heat treated at 100 °C for 24 hours. Then the mixture was filtered and washed with purified water several times and dried at 60 °C for 24 hours in a vacuum.
  • Characterization of the composites the morphology of the graphene sheets 10, the nanocarbons 25, and the GSNCs 20 were characterized by a transmission electron microscope. The morphology of the composites 20 was also examined by a scanning electron microscope. The specific surface areas of the graphene sheet 10, the nanocarbons 25, and the GSNCs 20 were measured by the Brunauer-Emmett-Teller (BET) method of nitrogen sorption at the liquid nitrogen temperature (77 K). Further, the composite materials 20 are stable at elevated temperatures and exhibit degradation or etching at the nanocarbon particle 25 sites.
  • BET Brunauer-Emmett-Teller
  • Preparation and characterization of the supercapacitor electrode A three-electrode-cell system was used to evaluate electrochemical performance using both cyclic voltammetry and galvanostatic charge/discharge techniques using an electrochemical workstation. A 1M H2SO4 aqueous solution was used as the electrolyte. A platinum sheet and a saturated Ag/AgCl electrode were used as the counter and the reference electrodes, respectively.
  • the working electrode 105 was prepared by casting a Nafion-impregnated sample onto a glassy carbon electrode with a diameter of 5 mm.
  • I is the current load (A)
  • At is the discharge time (s)
  • AV is the potential change during the discharge process
  • m is the mass of active material in a single electrode (g).
  • Graphene 10 is generally quite inert when exposed to gases such as oxygen and hydrogen at room temperature.
  • gases such as oxygen and hydrogen at room temperature.
  • oxygen exposure can cause preferential etching at defects and edges because the carbon atoms at the defects and edges are extremely reactive (this is because the p z electrons of these carbon atoms may not be involved in the conjugated electron system).
  • the carbon atoms in the graphene bulk remain inert even at high temperatures.
  • carbon atoms both at defects and at the edges of a graphene sheet become very active when a reactive metal is positioned proximate to these atoms.
  • Pt nanoparticles 150 may be used to etch graphene 10 through the catalytic hydrogenation of carbon, where carbon atoms on the graphene edges dissociate on the surface of Pt nanoparticle 150 and then react with H 2 at the Pt nanoparticle 150 surface to form methane. This process is shown schematically in Fig. 6. In contrast, such etching does not occur on graphene materials at carbon black or like carbonaceous particle sites.
  • the mechanism of etching of graphene 10 by Pt nanoparticles 150 at elevated temperature was observed in-situ using high-resolution environmental transmission electron microscopy.
  • Graphene sheets 10 were loaded with 20 weight percent of Pt nanoparticles 150, and subsequently placed onto a lacey carbon TEM grid.
  • the Pt nanoparticles 150 are typically sized between a few nanometers up to ten microns across, and may even be larger. More typically, the Pt nanoparticles are between about 5 and about 80 nanometers in diameter, although the Pt nanoparticles 150 may more typically range from about 10 nanometers to about 50nanometers in diameter.
  • the Pt nanoparticles 150 are typically generally spherical, but may exhibit other morphologies.
  • the nanoparticles 150 may be made of PT-like materials, such as PT, Pd, Ni, combinations thereof, and the like.
  • the graphene sheets 10 were loaded with 20 weight percent Pt nanoparticles 150, but the nanoparticle bading may typically vary from less than about 1 weight percent to as much as 50 weight percent, or more.
  • the graphene samples 10 were heated to 800 °C and hydrogen gas was slowly introduced into the TEM objective lens, and equilibrated at a pressure of approximately 50 mTorr. As the graphene 10 began to etch adjacent the Pt nanoparticles 150, the process was imaged continuously through the use of a high-frame rate camera. Image sequences extracted therefrom are presented as Figure 7A-7F. Initially, the Pt nanoparticles 150 were static after the hydrogen gas was introduced. Eventually, as shown in FIGs. 7A-7C, the Pt
  • nanoparticles 150 began to react with the graphene 10 at defect sites and the hydrogen gas to produce methane. Only those carbon atoms making up the graphene sheet 10 that were in direct contact with these Pt nanoparticles 150 were able to participate in this Pt-catalyzed hydrogenation reaction 155. Once the process was initiated, the conversion process was able to continue, as there are an abundance of defects sites created continuously following the onset of the etching process 155, leading to a self-sustaining reaction. In this case a straight trench was etched through the graphene sheet 10 (Fig. 7C). In other cases, the etching process 155 did not follow a straight line, but rather followed a more tortuous pathway (FIGs. 7D-7F).
  • the Pt nanoparticles 150 were observed to maintain a crystallographic relationship with the graphene sheet 10. After etching 155, the Pt nanoparticles 150 are typically reclaimed and saved for future use. These observations indicate that the interaction between the Pt 150 and the graphene 10 at elevated temperature can create a variety of in-plane nanostructures 160 in the graphene 10. The result of these interactions is the formation of nanoscale trenches, ribbons and islands 160 - and thus a dense network of edge sites 165.
  • the graphene sheets 10 are heated to a temperature sufficient for the etching process 155 to occur at a desired rate.
  • the graphene sheets 10 carrying dispersed Pt nanoparticles 150 are typically heated to at least about 700 degrees Celsius, and are more typically heated to a temperature in the range from 750 degrees Celsius to 900 degrees Celsius.
  • a hydrogen gas environment supports the Pt-catalyzed hydrogenation reaction 155, although other reducing environments may also be selected.
  • each carbon atom uses 3 of its 4 valance band (2s, 2p) electrons (which occupy the sp 2 orbits) to form covalent bonds with the neighboring carbon atoms in the same plane.
  • Each carbon atom in the graphene 10 contributes its fourth lone electron (occupying the p z orbit) to form a delocalized electron system.
  • the carbon atoms in the graphene plane 10 (excluding the carbon atoms on the defect sites such as the edges and holes) are saturated carbon atoms, with the three sp 2 electrons forming three covalent bonds and the fourth p z electron forming a ;rbond.
  • nanostructures of trenches, ribbons and islands 160 in the multilayer graphene sheets 10 are anisotropic, having different properties in-plane and out-plane.
  • the carbon atoms along the edges of the resulting trenches, ribbons, and the islands 160 are likely to be unsaturated, with one of the electrons in the sp 2 orbitals not forming a covalent bond with the other carbon atoms.
  • the resulting material provides an important platform for a wide variety of applications, including in catalysis, biomedical science, polymer science and energy science. This is because these unsaturated carbon atoms allow graphene 10 to be functionalized by chemically grafting other compounds or groups thereonto. Thus, these functionalized graphene 170 can be used, for example, sensors, catalysts, sorbents, and the like. Without such features, it is difficult to chemically graft compounds or groups onto graphene 10. These unsaturated carbons also promote the establishment of weak bonding between graphene and other species.
  • One such application is gas physisorption. Of particular interest is the physisorption of carbon dioxide.
  • the p z electrons and one sp 2 electron of these unsaturated carbon atoms at the defects sites will be available for bonding and will more readily form bonds with C0 2 molecules, which could in turn result in a significant improvement in C0 2 adsorption.
  • the adsorbed C0 2 molecules (or other gas molecules) may be stored for later removal or reaction.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Power Engineering (AREA)
  • Electrochemistry (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • General Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Nanotechnology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Carbon And Carbon Compounds (AREA)
  • Electric Double-Layer Capacitors Or The Like (AREA)

Abstract

La présente invention concerne un matériau composite de carbone, comprenant une pluralité de feuilles de graphène espacées, chaque feuille respective ayant des surfaces opposées globalement planes, et une pluralité de particules carbonées fonctionnalisées. Au moins certaines des particules carbonées fonctionnalisées sont disposées entre chaque paire de feuilles de graphène adjacentes, et chaque particule carbonée fonctionnalisée respective est fixée à la paire respective de feuilles de graphène adjacentes. Chaque feuille de graphène respective comprend au moins une couche de graphène, et au moins certaines parties des paires de feuilles de graphène adjacentes respectives sont orientées sensiblement parallèlement les unes aux autres.
PCT/US2012/024894 2011-02-13 2012-02-13 Composites de graphène nano-structurés à surface élevée et dispositifs capacitifs les intégrant Ceased WO2012109665A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201161442281P 2011-02-13 2011-02-13
US61/442,281 2011-02-13

Publications (1)

Publication Number Publication Date
WO2012109665A1 true WO2012109665A1 (fr) 2012-08-16

Family

ID=46638991

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2012/024894 Ceased WO2012109665A1 (fr) 2011-02-13 2012-02-13 Composites de graphène nano-structurés à surface élevée et dispositifs capacitifs les intégrant

Country Status (1)

Country Link
WO (1) WO2012109665A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015109272A1 (fr) * 2014-01-17 2015-07-23 The Trustees Of Dartmouth College Matériau et procédé de fabrication d'électrodes et de filtres poreux à base d'un composite oxyde de graphène calqué sur la glace-nanotubes de carbone, et leurs applications
WO2018153122A1 (fr) * 2017-02-24 2018-08-30 宁德新能源科技有限公司 Matériau d'électrode négative en graphite modifié, son procédé de préparation et batterie rechargeable
WO2019006044A1 (fr) * 2017-06-28 2019-01-03 Massachusetts Institute Of Technology Microparticules électroniques quasi-bidimensionnelles
CN110787770A (zh) * 2019-10-18 2020-02-14 南京领丰新材料科技有限公司 一种石墨烯改性空气净化材料及其制备方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030098640A1 (en) * 2001-11-27 2003-05-29 Fuji Xerox Co., Ltd. Hollow graphene sheet structure, electrode structure, process for the production thereof, and device thus produced
US20060165988A1 (en) * 2002-04-09 2006-07-27 Yet-Ming Chiang Carbon nanoparticles and composite particles and process of manufacture
WO2009143405A2 (fr) * 2008-05-22 2009-11-26 The University Of North Carolina At Chapel Hill Synthèse de feuillets de graphène et composites nanoparticulaires en comprenant
US20090291270A1 (en) * 2008-03-24 2009-11-26 The Regents Of The University Of California Graphene-based structure, method of suspending graphene membrane, and method of depositing material onto graphene membrane
US20100327847A1 (en) * 2007-09-12 2010-12-30 President And Fellows Of Harvard College High-Resolution Molecular Sensor

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030098640A1 (en) * 2001-11-27 2003-05-29 Fuji Xerox Co., Ltd. Hollow graphene sheet structure, electrode structure, process for the production thereof, and device thus produced
US20060165988A1 (en) * 2002-04-09 2006-07-27 Yet-Ming Chiang Carbon nanoparticles and composite particles and process of manufacture
US20100327847A1 (en) * 2007-09-12 2010-12-30 President And Fellows Of Harvard College High-Resolution Molecular Sensor
US20090291270A1 (en) * 2008-03-24 2009-11-26 The Regents Of The University Of California Graphene-based structure, method of suspending graphene membrane, and method of depositing material onto graphene membrane
WO2009143405A2 (fr) * 2008-05-22 2009-11-26 The University Of North Carolina At Chapel Hill Synthèse de feuillets de graphène et composites nanoparticulaires en comprenant

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
MCALLISTER ET AL.: "Single Sheet Functionalized Graphene by Oxidation and Thermal Expansion of Graphite", CHEMISTRY OF MATERIALS, vol. 19, no. 18, 25 May 2007 (2007-05-25), pages 4396 - 4404, Retrieved from the Internet <URL:http://pubs.acs.org/doi/abs/10.1021/cm0630800> [retrieved on 20120515] *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015109272A1 (fr) * 2014-01-17 2015-07-23 The Trustees Of Dartmouth College Matériau et procédé de fabrication d'électrodes et de filtres poreux à base d'un composite oxyde de graphène calqué sur la glace-nanotubes de carbone, et leurs applications
WO2018153122A1 (fr) * 2017-02-24 2018-08-30 宁德新能源科技有限公司 Matériau d'électrode négative en graphite modifié, son procédé de préparation et batterie rechargeable
WO2019006044A1 (fr) * 2017-06-28 2019-01-03 Massachusetts Institute Of Technology Microparticules électroniques quasi-bidimensionnelles
US20200027921A1 (en) * 2017-06-28 2020-01-23 Massachusetts Institute Of Technology Nearly 2d electronic microparticles
US11121176B2 (en) 2017-06-28 2021-09-14 Massachusetts Institute Of Technology Nearly 2D electronic microparticles
CN110787770A (zh) * 2019-10-18 2020-02-14 南京领丰新材料科技有限公司 一种石墨烯改性空气净化材料及其制备方法

Similar Documents

Publication Publication Date Title
US9656862B2 (en) High surface area nano-structured graphene composites and capacitive devices incorporating the same
Pang et al. Applications of 2D MXenes in energy conversion and storage systems
Hu et al. Three-dimensional network architecture with hybrid nanocarbon composites supporting few-layer MoS2 for lithium and sodium storage
Kumar et al. Graphene-wrapped and cobalt oxide-intercalated hybrid for extremely durable super-capacitor with ultrahigh energy and power densities
Yu et al. MXene/carbon nanotube hybrids: synthesis, structures, properties, and applications
Patil et al. Nanostructured pseudocapacitive materials decorated 3D graphene foam electrodes for next generation supercapacitors
Yao et al. Hierarchical NiO@ NiCo2O4 core–shell nanosheet arrays on Ni foam for high-performance electrochemical supercapacitors
Khan et al. Molybdenum sulfide/graphene-carbon nanotube nanocomposite material for electrocatalytic applications in hydrogen evolution reactions
Yang et al. Design of ZIF-based CNTs wrapped porous carbon with hierarchical pores as electrode materials for supercapacitors
Wang et al. Solvothermal-induced 3D macroscopic SnO2/nitrogen-doped graphene aerogels for high capacity and long-life lithium storage
Wang et al. Preparation of high-surface-area carbon nanoparticle/graphene composites
Hou et al. Hierarchical core–shell structure of ZnO nanorod@ NiO/MoO2 composite nanosheet arrays for high-performance supercapacitors
Lu et al. Monolithic 3D cross-linked polymeric graphene materials and the likes: preparation and their redox catalytic applications
Xu et al. Review on recent advances in two‐dimensional nanomaterials‐based cathodes for lithium‐sulfur batteries
Wang et al. Intertwined Nanocarbon and Manganese Oxide Hybrid Foam for High‐Energy Supercapacitors
Guan et al. Atomic‐Layer‐Deposition‐Assisted Formation of Carbon Nanoflakes on Metal Oxides and Energy Storage Application
Chen et al. Graphitic carbon nitride nanomaterials for high‐performance supercapacitors
Kim et al. In situ synthesis of three-dimensional self-assembled metal oxide–reduced graphene oxide architecture
US20110051316A1 (en) Mesoporous Metal Oxide Graphene Nanocomposite Materials
Yao et al. Vertically Co-oriented Mn-metal–organic framework grown on 2D cation-intercalated manganese oxide via a self-sacrificing template process for a high-performance asymmetric supercapacitor
Karthikeyan et al. Electrochemical performance of reduced graphene oxide (rGO) decorated lanthanum oxide (La2O3) composite nanostructure as asymmetric supercapacitors
Yasin et al. Design of zinc oxide nanoparticles and graphene hydrogel co-incorporated activated carbon for efficient capacitive deionization
Deng et al. Facile strategy to low-cost synthesis of hierarchically porous, active carbon of high graphitization for energy storage
Yi et al. Preparation of single-atom Ag-decorated MnO2 hollow microspheres by redox etching method for high-performance solid-state asymmetric supercapacitors
Jadhav et al. Probing electrochemical charge storage of 3D porous hierarchical cobalt oxide decorated rGO in ultra-high-performance supercapacitor

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12744690

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 12744690

Country of ref document: EP

Kind code of ref document: A1