WO2022218088A1 - Procédé de préparation d'un film de graphène poreux, film de graphène poreux, et électrode - Google Patents

Procédé de préparation d'un film de graphène poreux, film de graphène poreux, et électrode Download PDF

Info

Publication number
WO2022218088A1
WO2022218088A1 PCT/CN2022/081128 CN2022081128W WO2022218088A1 WO 2022218088 A1 WO2022218088 A1 WO 2022218088A1 CN 2022081128 W CN2022081128 W CN 2022081128W WO 2022218088 A1 WO2022218088 A1 WO 2022218088A1
Authority
WO
WIPO (PCT)
Prior art keywords
graphene oxide
porous
oxide film
reduced
porous graphene
Prior art date
Application number
PCT/CN2022/081128
Other languages
English (en)
Chinese (zh)
Inventor
王晓京
Original Assignee
王晓京
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 王晓京 filed Critical 王晓京
Publication of WO2022218088A1 publication Critical patent/WO2022218088A1/fr

Links

Images

Classifications

    • 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
    • H01G11/84—Processes for the manufacture of hybrid or EDL capacitors, or components thereof
    • H01G11/86—Processes for the manufacture of hybrid or EDL capacitors, or components thereof specially adapted for electrodes
    • 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
    • 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
    • Y02E60/13—Energy storage using capacitors

Definitions

  • the present invention relates to a method for preparing a porous graphene film, a porous graphene film and an electrode.
  • the present invention also relates to the use of porous graphene membranes in energy storage devices such as capacitors, supercapacitors, batteries and fuel cells.
  • Supercapacitors also known as “electric double-layer capacitors" are electrochemical capacitors that have much higher capacitance values than other capacitors. Supercapacitors are widely used in energy storage and energy supply due to their high energy density, fast charge/discharge capability, long life of over one million charge cycles, and ability to operate in a wide temperature range from -40°C to 70°C .
  • a typical supercapacitor includes two electrodes separated by an ion-permeable membrane ("separator layer”), and a pair of current collectors connected to the electrodes, respectively.
  • Activated carbon is the most widely used electrode material in conventional supercapacitors. Although in theory activated carbon can provide a large specific surface area to accommodate a large number of ions, most of the pores are non-connected, and ions cannot effectively utilize its surface area, thus resulting in a low specific capacitance and a maximum energy density of approximately 5-7Wh kg -1 . Therefore, in order to further improve the specific capacitance and energy density of supercapacitors, it is necessary to develop electrode materials with large specific surface area and high electrical conductivity.
  • the pure graphene material has an ultra-large theoretical specific surface area of 2630 m 2 /g and excellent electrical conductivity (>1000 S/m). What's more, as a two-dimensional layered material, the pores inside the material are all interconnected, so ions can fully attach to the surface of this material. Therefore, graphene has been regarded as the most promising electrode material for high-performance supercapacitors. In the past decade, graphene and its derivatives have been widely developed as supercapacitor electrode materials to replace activated carbon. There have been some studies to achieve high-performance graphene supercapacitors.
  • a first aspect of the present invention provides a method, comprising: firstly combining a freezing and drying process (freeze-drying method) to fabricate a porous continuous interconnected graphene oxide (GO) network structure, wherein the GO is porous GO and the pore size is and porosity can be adjusted by controlling the concentration of graphene oxide.
  • a freezing and drying process freeze-drying method
  • a high-pressure process is used to enhance the mechanical structural strength of graphene oxide and reduce the thickness of the graphene oxide film produced by the freeze-drying method.
  • the porosity and pore size of the graphene oxide structure in this step can be controlled by the applied pressure.
  • the graphene oxide is irradiated with a light beam to form pre-reduced graphene oxide (PRGO) having a three-dimensional (3D) network, which is porous.
  • PRGO pre-reduced graphene oxide
  • 3D three-dimensional
  • microwave (MW) radiation was further used to irradiate the pre-reduced graphene oxide with 3D network to achieve the reduction of graphene oxide.
  • the degree of reduction of reduced graphene oxide (RGO) in this step can be controlled by the intensity and duration of microwave radiation.
  • an electrode comprising reduced graphene oxide having a 3D network, wherein the pore structure of the 3D network is interconnected.
  • the present invention also provides a device for making 3D porous reduced graphene oxide, comprising:
  • an irradiation device for emitting a light beam for prereducing the graphene oxide network
  • a device for generating microwave radiation that further reduces the pre-reduced graphene oxide network to form a 3D porous reduced graphene oxide network.
  • the present invention also provides a method comprising: freeze-drying graphene oxide to form a 3D porous graphene oxide network, wherein the graphene oxide comprises a single-layer or multi-layer porous graphene oxide film.
  • the present invention also provides a method, comprising:
  • Pressurized equipment is used to compress a 3D porous graphene oxide network, wherein the graphene oxide comprises a single or multi-layer porous graphene oxide film.
  • the present invention further provides a method, comprising:
  • a 3D porous graphene oxide network is irradiated with a light beam to form pre-reduced graphene oxide (PRGO), wherein the 3D porous graphene oxide network comprises a single or multi-layer porous graphene oxide film.
  • PRGO pre-reduced graphene oxide
  • the present invention also provides a method, comprising:
  • the 3D porous pre-reduced graphene oxide network is irradiated with microwave radiation to form reduced graphene oxide, wherein the 3D porous pre-reduced graphene oxide network comprises a single or multi-layer porous graphene oxide film.
  • FIG. 1 is a flowchart of a method for forming an RGO according to some embodiments of the present application.
  • FIG. 2 is a photograph of a freeze-dried sample of GO slurry (slurry concentration of 169.9 mg/ml) according to some embodiments of the present application.
  • FIG 3 is a scanning electron microscope image of a porous RGO film according to some embodiments of the present application.
  • FIG. 5 is an elemental analysis result of a reduced graphene oxide film according to some embodiments of the present application.
  • CV 6 is a cyclic voltammetry (CV) curve of a supercapacitor made of GO slurry (slurry concentration of 169.9 mg/ml) scanned at different speeds according to some embodiments of the present application.
  • CCCD 7 is a constant current charge-discharge (CCCD) curve scanned at different current densities for a supercapacitor made of GO slurry (slurry concentration of 169.9 mg/ml) according to some embodiments of the present application.
  • CCCD constant current charge-discharge
  • FIG. 8 is a plot of specific capacitance versus current density swept at different current densities for a supercapacitor made of GO slurry (slurry concentration of 169.9 mg/ml) according to some embodiments of the present application.
  • FIG. 9 is an electrical impedance spectroscopy curve scanned at different current densities for a supercapacitor made of GO slurry (slurry concentration of 169.9 mg/ml) according to some embodiments of the present application.
  • FIG. 10 is a Ragone plot of supercapacitors made from GO slurry (slurry concentration of 169.9 mg/ml) scanned at different current densities according to some embodiments of the present application.
  • FIG. 11 is a cyclic voltammetry (CV) curve scanned at different speeds of a supercapacitor made of GO slurry (slurry concentration of 169.9 mg/ml) according to some embodiments of the present application.
  • CV cyclic voltammetry
  • CCCD 12 is a constant current charge-discharge (CCCD) curve scanned at different current densities for a supercapacitor made of GO slurry (slurry concentration of 72 mg/ml) according to some embodiments of the present application.
  • CCCD constant current charge-discharge
  • FIG. 13 is a plot of specific capacitance versus current density scanned at different current densities for a supercapacitor made of GO slurry (slurry concentration of 72 mg/ml) according to some embodiments of the present application.
  • FIG. 14 is an electrical impedance spectroscopy curve scanned at different current densities for a supercapacitor made of GO slurry (slurry concentration of 72 mg/ml) according to some embodiments of the present application.
  • 15 is a Ragone plot of supercapacitors made from GO slurry (slurry concentration of 72 mg/ml) scanned at different current densities according to some embodiments of the present application.
  • a conventional capacitor includes two conventional electrodes, a separator between the two electrodes, and a pair of current collectors (one for each electrode). Conventional electrodes have no pores, and charge is stored on the surface of conventional electrodes. A current collector is connected to the electrodes to conduct charge from the electrodes.
  • Supercapacitors use porous electrodes, and charges can attach to the porous surface of the porous electrode, ie, in the pores and on the surface of the porous electrode.
  • the theoretical capacitance C of the supercapacitor is proportional to the specific surface area A of the electrode, namely
  • Specific surface area A is defined as the total surface area of a material per unit mass or solid or bulk volume.
  • the capacitance C can be increased by increasing the specific surface area A.
  • the electrodes of supercapacitors can be made of activated carbon, which typically has a complex porous structure that provides high surface area.
  • the measured capacitance of supercapacitors with activated carbon electrodes is often much lower than the calculated "theoretical" capacitance, for example, because some of the pores in the activated carbon are too small for electrolyte ions to diffuse into them, and because it is difficult to The electric double layer structure is formed in a small space.
  • Graphene is an allotrope of carbon.
  • Graphene includes at least one two-dimensional flake consisting of a single layer of sp - bonded carbon atoms arranged in a hexagonal honeycomb structure.
  • Graphene has a very stable structure, high electrical conductivity, high toughness, high strength and large specific surface area, which are ideal properties for electrode materials in supercapacitors.
  • Graphene oxide is an oxidized form of graphene in which a monolayer is attached with oxygen-containing groups.
  • Graphene oxide can be chemically reduced to convert graphene oxide to reduced graphene oxide: Reduced graphene oxide is a material with higher electrical conductivity than graphene oxide.
  • Described herein are methods for the preparation or fabrication of reduced graphene oxide structures for use in supercapacitor porous electrodes.
  • the methods described herein can allow the creation of one or more pores of a selected size (eg, having diameters between 1 nm and 1000 nm, termed "nanoporous structures") between graphene oxide layers, and allow a large number of Production of reduced graphene oxide structures and electrodes with reduced graphene oxide structures that can be used in supercapacitors.
  • the methods described herein may also allow the fabrication of supercapacitors with reduced graphene oxide electrodes with variable properties such as geometric design and/or device footprint (ie, the amount of space occupied by the electrodes or supercapacitors). select features and allow direct integration of supercapacitors with other electrical devices. Using the methods described in this application, supercapacitors with reduced graphene oxide electrodes can be fabricated in a simple, efficient, and low-cost manner.
  • the method for preparing a reduced graphene oxide structure described in this application includes the following aspects: freeze-drying graphene oxide to form a graphene oxide film with a three-dimensional porous structure, compressing the graphene oxide film with a three-dimensional porous structure, using a light beam A graphene oxide film with a three-dimensional porous structure is irradiated to form a pre-reduced graphene oxide film, and the pre-reduced graphene oxide film is irradiated with microwaves to form a reduced graphene oxide film.
  • the press-compressed graphene oxide includes one or more layers of porous graphene oxide films.
  • Porous graphene oxide membranes employed in the methods of embodiments described herein include multilayer arrays comprising graphene oxide sheets.
  • multilayer array generally refers to a graphene substrate comprising multiple planes stacked on top of each other in an overlapping manner to form a layer-like structure.
  • the planar sheets in a multilayer array may partially or completely overlap each other.
  • Multilayer arrays are usually three-dimensional structures.
  • graphene-based may be used in this application as a general description of graphene-containing materials, including graphene oxide and reduced graphene oxide.
  • planar sheets in the multilayer may be composed of graphene oxide (eg, in the case of graphene oxide films).
  • the sheet may consist of reduced graphene oxide or a mixture of graphene oxide and reduced graphene oxide (eg, in the case of reduced graphene oxide films).
  • Porous graphene oxide films as used herein include graphene oxide sheets, wherein at least some of the graphene oxide sheets contain one or more pores.
  • a portion of the graphene oxide sheets in the multilayer array includes at least one hole, while another portion of the graphene oxide sheets includes no holes.
  • each graphene oxide sheet in the graphene oxide film includes at least one pore.
  • the holes in the graphene oxide sheets are carbon atomic vacancies in the plane of the sheet, which disrupt the regular hexagonal carbon lattice of the sheet. These pores can be distributed randomly or with high regularity in the graphene oxide sheets. Depending on their diameter, pores can be classified as micropores (less than 2 nm in diameter), mesopores (with diameters ranging from about 2 nm to about 50 nm in diameter), or macropores (greater than 50 nm in diameter).
  • the graphene oxide sheets in the porous graphene oxide film are also separated or spaced from each other. Therefore, there are interlayer spaces between the graphene oxide sheets.
  • the degree to which graphene oxide sheets are separated from each other ie, the distance
  • the separation distance or interlayer spacing between sheets may be referred to herein as the separation distance or interlayer spacing between sheets.
  • the porous graphene oxide membranes used in the methods of the embodiments described herein contain at least one oxygen-containing functional group.
  • the graphene oxide film may include multiple oxygen-containing functional groups. Such oxygen-containing functional groups are typically present in at least one graphene oxide sheet that forms part of the porous graphene oxide film.
  • oxygen-containing functional group generally refers to a functional group covalently bonded to a carbon atom of a graphene oxide sheet, eg, epoxy, hydroxyl, carbonyl, carboxyl. Such oxygen-containing functional groups may be the result of oxidation reactions.
  • the porous graphene oxide film comprises oxygen-containing functional groups located in at least one selected from the group consisting of (i) pores of graphene oxide sheets and (ii) between two or more graphene oxide sheets.
  • the porous graphene oxide film comprises oxygen-containing functional groups located in the pores of the graphene oxide sheets and between two or more graphene oxide sheets.
  • the oxygen-containing functional groups located in the pores of the graphene oxide sheet can be located at the edges of the pores.
  • the pores in the graphene oxide sheet may contain at least one oxygen-containing functional group, and may contain multiple oxygen-containing functional groups.
  • each pore may contain at least one oxygen-containing functional group.
  • Oxygen-containing functional groups located between two or more graphene oxide sheets can be covalently bonded to the surface of the graphene oxide sheets and extend from the basal plane of the graphene oxide sheets into the interlayer space existing between the overlapping sheets . In this way, overlapping graphene oxide sheets can be spaced or separated from each other by oxygen-containing functional groups.
  • the porous graphene oxide film contains at least one oxygen-containing functional group, and may contain a plurality of oxygen-containing functional groups located between two or more graphene oxide sheets.
  • porous graphene oxide films useful in embodiments described herein have a high degree of oxidation.
  • Porous graphene oxide films with a high degree of oxidation may contain an amount of oxygen-containing functional groups to provide an oxygen content in the graphene oxide of at least about 15%, preferably at least about 20%, more preferably at least about 25%.
  • the oxygen content of the porous graphene oxide film can be determined by appropriate techniques.
  • the oxygen content and thus the degree of oxidation can be determined by X-ray photoelectron spectroscopy (XPS), which measures the type and percentage of each chemical element present in the material.
  • XPS X-ray photoelectron spectroscopy
  • the graphene oxide flakes in the graphene oxide film may have a carbon to oxygen ratio (C:O) determined by XPS of from about 2:1 to about 4:1, preferably from about 2.5:1 to 3:1 .
  • Porous graphene oxide films with a high degree of oxidation may have a large number of pores in the graphene oxide sheets and large interlayer spacing between the sheets.
  • a porous graphene oxide film with a high degree of oxidation may have graphene oxide sheets with interlayer spacing of up to (Egypt).
  • porous graphene oxide membranes used in the methods of the embodiments described herein can be obtained from commercial sources.
  • porous graphene oxide films can be synthesized from graphite, for example, by producing graphene oxide films from graphene oxide solutions.
  • Graphene oxide slurries for forming graphene oxide films can be prepared by the following methods:
  • Graphene oxide is formed by the method of graphite oxide
  • the graphite oxide is exfoliated in a solvent to form a graphene oxide solution.
  • purified natural graphite powder eg., ultra-high purity natural graphite powder
  • graphite oxide e.g., ultra-high purity natural graphite powder
  • Graphite can be oxidized using conventional methods to produce graphite oxide.
  • oxidation methods such as the Hammers method (Journal of the American Chemical Society, 1958, 80(6), 1339) or a modified Hammers method (ACS nano, 2010, 4(8), 4806) may be employed.
  • Graphene oxide produced by oxidation of graphite includes a plurality of planar graphene oxide sheets, each graphene oxide sheet comprising at least one oxygen-containing functional group.
  • Graphite oxide is exfoliated to produce graphene oxide sheets.
  • the exfoliation of graphite oxide can be performed using exfoliation techniques and conditions known in the art.
  • graphene oxide slurries can be made by suspending and exfoliating graphene oxide in a solvent under conditions sufficient to cause separation of the graphene oxide sheets.
  • the graphene oxide slurry includes separated graphene oxide sheets suspended in a solvent.
  • the isolated graphene oxide sheets can be in the form of a single layer or several layers.
  • Graphene oxide can be suspended in any suitable solvent.
  • the graphite oxide is suspended in an aqueous solvent.
  • the aqueous solvent is substantially free of organic solvents.
  • the aqueous solvent is water. The use of aqueous solvents allows the preparation of graphene oxide films in an environmentally friendly manner.
  • Graphene oxide can be exfoliated in the slurry using a suitable exfoliation technique.
  • the graphite oxide in the slurry can be mechanically exfoliated to produce graphene oxide sheets, which are then dispersed in a solvent. Mechanical exfoliation can be achieved using sonication.
  • sonication involves the application of sonic energy to agitate the graphite oxide and ultimately result in the destruction of the graphene oxide lattice layered structure in the graphite material.
  • the disruption of the lattice layered structure leads to the separation of graphene oxide sheets.
  • Ultrasonic treatment means and conditions known to be useful for exfoliating graphite oxide can be used. Sonication can be performed with a sonicator or a sonication bath.
  • the frequency of the ultrasound can be in the range of about 20 kHz to about 400 kHz, preferably at a frequency of about 20 kHz to sonicate the graphite oxide.
  • graphite oxide is sonicated to produce graphene oxide sheets.
  • Sonication can be performed for a period of seconds to hours.
  • the time can vary depending on the amount of graphite oxide to be exfoliated and the frequency of sonication.
  • the graphite oxide can be sonicated for about 5 minutes to several hours, preferably about 20 minutes to about 1 hour, more preferably about 30 minutes.
  • the graphene oxide slurry may contain graphene oxide in the form of a single layer and/or several layers. Few-layer forms can include 2 to 10 graphene-based sheets.
  • At least some of the graphene oxide in the graphene oxide slurry contains at least one pore. In some embodiments, at least some of the graphene oxide in the slurry contains a plurality of pores. The generation of pores may be caused by the defects introduced into the graphene oxide sheets.
  • Graphene oxide slurries can be used to form porous graphene oxide films.
  • Graphene oxide films can be prepared using conventional film forming techniques known to those skilled in the art.
  • the graphene oxide film can be formed by film forming techniques known to those skilled in the art.
  • the formation of the porous graphene oxide film involves applying a graphene oxide solution to the substrate to form a coating, and removing the solvent from the coating to leave the porous graphene oxide film on the substrate.
  • the resulting graphene oxide film can be exfoliated from the substrate if desired.
  • the film can be peeled off from the substrate.
  • forming the porous graphene oxide film involves a freeze-drying process.
  • the graphene oxide slurry can be dropped onto the substrate to form a coating on the substrate.
  • the graphene oxide slurry is frozen for a period of time (for example, 10 hours) at a low temperature in a refrigerator (for example, -25° C.), and then vacuum-dried to remove the solvent in the coating to form a 3D porous graphene oxide film.
  • the size of the substrate and/or the size of the droplets can determine the size of the porous graphene oxide film.
  • the thickness of the graphene oxide film can be determined by the concentration and amount of graphene oxide in the slurry.
  • the porous graphene oxide film may involve compression treatment with a certain pressure (eg, 1200 psi compression) to further reduce the thickness of the graphene oxide film and control the size of the pore size.
  • a certain pressure eg, 1200 psi compression
  • the final thickness and pore size of the compressed graphene oxide film may depend on the applied pressure.
  • the method of an embodiment includes pre-reducing and fully reducing the graphene oxide film to finally produce a reduced graphene oxide film.
  • Prereduction involves irradiating the graphene oxide film with a light beam.
  • Complete reduction involves irradiating pre-reduced graphene oxide films with microwaves.
  • the irradiation method for pre-reduction of graphene oxide may also be referred to hereinafter as "photoreduction” or "laser three-dimensional printing”.
  • the irradiation method for complete reduction of graphene oxide may also be referred to as "microwave reduction” hereinafter.
  • the pre-reduction and full reduction process can reduce one or more oxygen-containing functional groups present in one or more graphene oxide sheets in the porous graphene oxide film.
  • the reduction process reduces at least one oxygen-containing functional group in the plurality of graphene oxide sheets.
  • oxygen-containing functional groups located (i) in the pores of the graphene oxide sheets and/or (ii) between two or more graphene oxide sheets are reduced.
  • the pre-reduction and full reduction process can reduce oxygen-containing functional groups located in the pores of graphene oxide sheets or between graphene oxide layers. And in some embodiments, the irradiation reduces at least a portion of the oxygen-containing functional groups between the graphene oxide sheets.
  • porous pre-reduced or fully reduced graphene oxide film After the reduction process, a porous pre-reduced or fully reduced graphene oxide film is produced.
  • the porous pre-reduced or fully reduced graphene oxide film includes at least one reduced graphene oxide sheet, and can include a plurality of reduced graphene oxide sheets. Reduced graphene oxide sheets are formed when at least one oxygen-containing functional group in the graphene oxide sheets is reduced and removed.
  • the pre-reduction and/or full reduction is performed in a substantially oxygen-free environment, such as in a vacuum or in an inert atmosphere such as nitrogen or argon.
  • a portion of the graphene oxide sheets in the porous graphene oxide film are pre-reduced or fully reduced.
  • the resulting film comprises a mixture of graphene oxide sheets and reduced graphene oxide sheets.
  • pre-reduction and full reduction process conditions can be adjusted to vary the amount of oxygen-containing functional groups that are reduced, and thus the degree of reduction.
  • pre-reduction of the graphene oxide film is achieved by irradiating the graphene oxide film with a light beam.
  • Optical radiation can induce thermal (ie, photothermal) or chemical (ie, photochemical) effects that reduce at least one oxygen-containing functional group present in the porous graphene oxide film.
  • thermal radiation ie, photothermal
  • chemical (ie, photochemical) effects that reduce at least one oxygen-containing functional group present in the porous graphene oxide film.
  • light or radiation can include different forms of electromagnetic radiation, including optical radiation.
  • Photothermal reduction can be performed using any suitable wavelength of light or radiation. Suitable wavelengths may vary from the ultraviolet range (about 10 nm) to the infrared range (about 100 ⁇ m).
  • suitable wavelengths from a CO 2 laser may be from about 248 nm up to 10.6 ⁇ m.
  • Photothermal reduction can be performed using any suitable type of light or radiation source.
  • a suitable light source or radiation source preferably has sufficient power to generate a minimum amount of heat.
  • a suitable light source or radiation source has sufficient power to heat the porous graphene oxide film to a temperature of at least about 200°C during the reduction process.
  • Some examples of light sources that can be used to facilitate photothermal recovery include, but are not limited to, UV lamps, focused sunlight, and flashlights.
  • the graphene oxide film was irradiated with microwaves to completely reduce the graphene oxide film.
  • the microwave irradiation produces a thermal effect that reduces at least one oxygen-containing functional group present in the porous graphene oxide film.
  • Microwave reduction involves the use of microwaves to irradiate porous graphene oxide membranes (with and without prereduction) and generate localized heat in the membranes.
  • the heat generated after irradiation depends on the microwave source and the thermal properties of the graphene oxide film.
  • the pore size of the reduced graphene oxide material is initially controlled by the concentration of the freeze-dried graphene oxide slurry and the pressure of the compression process.
  • the trend is that the higher the concentration of the slurry, the smaller the pore size is, and the higher the pressure, the smaller the pore size is.
  • the control of the pore size of the reduced graphene oxide material can be achieved by controlling the reduction process.
  • Oxygen-containing functional groups can be removed by reduction, including pre-reduction and full reduction, and hydrophobic graphene domains can be formed.
  • gases such as CO, CO 2 and H 2 O vapor may be generated due to the removal of oxygen functional groups and water between the multiple graphene oxide sheets.
  • the gas may heat up at a high rate, which causes the gas volume to expand, creating pores between the layers.
  • the conductivity of the reduced graphene oxide material can be controlled by selecting or controlling the reduction parameters. Through reduction (including pre-reduction and full reduction) the oxygen functional group is removed, the sp2 network structure of graphene is restored, and as a result, the electrical conductivity is improved.
  • the reduced graphene oxide structures produced according to the methods described above can be used for a range of applications including the fabrication of electrodes for supercapacitors.
  • the reduced graphene oxide structure produced according to the above method can be used to fabricate electrodes for supercapacitors.
  • the supercapacitor including the reduced graphene oxide structured electrode (hereinafter referred to as "reduced graphene oxide supercapacitor") prepared using the above method may have a sandwich structure.
  • the reduced graphene oxide supercapacitor may have a sandwich structure.
  • Each sandwich structure includes two electrodes, a separator sandwiched between the two electrodes, and a pair of current collectors connected to the electrodes.
  • a reduced graphene oxide electrode with pores is sandwiched between two metal current collectors separated by a separator (eg, a dielectric separator).
  • a separator eg, a dielectric separator
  • the method of fabricating a reduced graphene oxide supercapacitor with a sandwich structure may include the following steps:
  • the method of making a reduced graphene oxide supercapacitor may further include using any other steps known to those skilled in the art to make a supercapacitor.
  • the membranes and current collectors can be fabricated by any conventional method known to those skilled in the art.
  • the separator may be made of a graphene oxide film fabricated according to the methods described above.
  • a method 100 of forming reduced graphene oxide begins at step 102 .
  • the graphite is oxidized to produce graphite oxide.
  • the resulting graphite oxide is then exfoliated at step 106 to form a graphene oxide slurry.
  • a porous graphene oxide film is formed by freeze-drying.
  • the porous graphene oxide film formed at step 108 is compressed.
  • the graphene oxide film is irradiated with a light beam to prereduce the porous graphene oxide film.
  • the pre-reduced graphene oxide film is irradiated with microwaves to form a reduced graphene oxide structure that will be used as an electrode in a reduced graphene oxide supercapacitor.
  • the formed reduced graphene oxide structure is assembled with a metal current collector to form a reduced graphene oxide supercapacitor.
  • reduced graphene oxide (RGO) structures fabricated by the above methods reduced graphene oxide electrodes or reduced graphene oxide supercapacitors can provide many advantages or technical effects.
  • the energy density can be similar to that of lithium batteries.
  • Graphene oxide slurries can be synthesized directly from large graphitic materials with oxidizing agents, and graphene oxide films are fabricated by using low-cost synthesis techniques, such as the described freeze-drying technique. Pre-reduction of graphene oxide materials can be achieved using inexpensive laser diodes, and the full reduction process can be achieved using inexpensive microwave ovens. This process could allow reduced graphite oxide supercapacitors to be easily integrated with other electronic devices, such as solar panels.
  • the ultra-high power density can provide high current for electronic devices, and the charging of the reduced graphene oxide supercapacitor can be completed in a very short time.
  • Reduced graphene oxide supercapacitors can be thermally stable and chemically inert, so they can be used in harsh environments.
  • Reduced graphene oxide films may have high resistance to high temperatures, oxidizing agents, strongly acidic/basic reagents, or organic solvents.
  • the reduced graphene oxide film can have high mechanical strength. Due to its high mechanical strength, thermal and chemical stability, reduced graphene oxide supercapacitors can last longer than existing supercapacitors.
  • RGO structures, RGO electrodes, and RGO supercapacitors can be fabricated in an environmentally friendly manner using environmentally friendly solvents. Furthermore, RGO membranes can be non-toxic and compatible with biological samples.
  • Supercapacitors fabricated using the methods described above can be used in suitable applications, including one or more of the following: solar cells that can store energy directly (eg, by integrating the supercapacitor with solar panels); drones power supply; power supply for electric bicycles or vehicles; power supply for night vision goggles; power supply for military radios; power supply for military GPS equipment; power supply for solar road lighting; power supply for solar irrigation systems; power supply for mobile homes; in biomedical applications such as Power for biological implants; power for consumer electronics such as cell phone batteries; power for light rail and trams; smart microgrids; biosensors; rechargeable jackets for powering personal devices; rechargeables for powering personal devices bags; rechargeable bike helmets with built-in headlights; and power supplies for greenhouses or other grow-related applications.
  • solar cells that can store energy directly (eg, by integrating the supercapacitor with solar panels); drones power supply; power supply for electric bicycles or vehicles; power supply for night vision goggles; power supply for military radios; power supply for military GPS
  • Supercapacitors fabricated using the methods described above can be characterized by known electrochemical techniques, for example, any one or more of the following techniques: cyclic voltammetry, cyclic charge-discharge, leakage current measurements, self-discharge measurements and electrochemical impedance spectroscopy.
  • the exemplary experiments described below relate to the process of fabricating reduced graphene oxide (RGO) structures and reduced graphene oxide (RGO) supercapacitors, as well as the corresponding experimental results.
  • Natural graphite powder (SP-1, Bay Carbon) (20 g) was put into a solution of concentrated H 2 SO 4 (30 mL), K 2 S 2 O 8 (10 g) and P 2 O 5 (10 g) at 80°C middle. The resulting dark blue mixture was thermally separated and cooled to room temperature over 6 hours. The mixture was then carefully diluted with distilled water, filtered, and washed on the filter until the pH of the rinse water became neutral. The product was dried in air at ambient temperature overnight. Then, the peroxidized graphite is oxidized by the Hummers method. The oxidized graphite powder (20 g) was placed in cold ( 0 °C) concentrated H2SO4 (460 mL).
  • KMnO4 60 g was gradually added with stirring and cooling so that the temperature of the mixture was below 20°C. The mixture was then stirred at 35°C for 2 hours, and distilled water (920 mL) was added. The reaction was quenched by adding copious distilled water (2.8 L) and 30% H2O2 solution (50 mL ) within 15 minutes, then the color of the mixture changed to bright yellow. The mixture was filtered and washed with 1:10 HCl solution (5 L) to remove metal ions. The graphite oxide product was suspended in distilled water to give a viscous brown 2% dispersion which was dialyzed to completely remove metal ions and acids.
  • the synthesized graphite oxide was suspended in water to obtain a brown dispersion, which was dialyzed to completely remove residual salts and acids. Ultrapure Milli-Q water was used for all experiments.
  • the purified graphite oxide suspension was then dispersed in water to yield a 0.05 wt% dispersion.
  • the graphite oxide was exfoliated to graphene oxide by sonicating the dispersion using a Brandson Digital Sonifier (S450D, 500W, 30% amplitude) for 30 minutes.
  • the resulting brown dispersion was then centrifuged at 3000 rpm for 30 minutes using an Eppendorf 5702 centrifuge with a rotor radius of 14 cm to remove any unexfoliated graphite oxide (usually present in very small amounts).
  • the graphene oxide slurry was frozen in a refrigerator at -25 °C for 10 hours, and then vacuum-dried to obtain a graphene oxide film with a porous structure. Then the graphene oxide film was compressed several times to the graphene oxide thin layer under the pressure of 1200 PSI to enhance the mechanical strength of the graphene oxide film. Photographs of freeze-dried graphene oxide films on glass substrates are shown in Figure 2. These films are then peeled off the substrate to form free-standing graphene oxide films, which can also be shredded into small pieces.
  • the compressed graphene oxide thin layer was placed in a nitrogen chamber, where an infrared (IR) laser was introduced to prereduce the graphene oxide layer. With less than 1 second of laser irradiation, the entire graphene oxide layer will be completely reduced by a laser power of about 200W/ cm2 (power: 1.6W, laser spot size: 100 ⁇ m in diameter), the calculated movement of the laser relative to the film The speed is 10 mm/s, which is due to the very fast speed of the self-propagating domino-like reaction.
  • the laser-prereduced graphene oxide thin layer was transferred into a quartz glass container and filled with nitrogen to eliminate the influence of other gases. The membrane was then placed in a commercial microwave oven and reduced at full power (1000 W) for 30 seconds.
  • a scanning electron microscope (SEM) image of the reduced freeze-dried graphene oxide film is shown in FIG. 3 .
  • porous reduced graphene oxide films prepared in the above examples were analyzed by Raman spectroscopy. Some results are discussed below.
  • the Raman spectrum of the graphene oxide film produced by the suction filtration technique is shown in Figure 4.
  • Spectra of the porous reduced graphene oxide films produced by irradiation with a laser diode (LD) and irradiation with LD in combination with microwaves are shown in Figure 4, respectively.
  • the ratio of ID/ IG of the spectrum of this combined reduction mode decreases significantly, corresponding to a significant decrease in defect density.
  • the reduced graphene oxide film was also characterized by elemental analysis, and the histogram of its atomic weight is shown in FIG. 5 .
  • the voltage drop at the onset of discharge was 0.034V (for a current density of 0.5A/g), indicating very low ESR in the test cells.
  • a frequency response analysis (FRA) over the frequency range from 500kHz to 1MHz yields a Nyquist plot expressed as an electrical impedance spectrum (EIS).
  • EIS electrical impedance spectrum

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Manufacturing & Machinery (AREA)
  • Carbon And Carbon Compounds (AREA)
  • Electric Double-Layer Capacitors Or The Like (AREA)

Abstract

L'invention concerne un procédé de préparation d'un film de graphène poreux, un film de graphène poreux, une électrode, et un condensateur. Une technologie de lyophilisation est utilisée pour construire des réseaux continûment interconnectés d'oxyde de graphène poreux, et une technologie de forte compression est utilisée pour renforcer la résistance de structures mécaniques en oxyde de graphène. L'utilisation d'une irradiation par laser et micro-ondes pour réduire le film d'oxyde de graphène poreux réalise une réduction efficiente sur une grande étendue et permet d'obtenir des supercondensateurs à hautes performances.
PCT/CN2022/081128 2021-04-12 2022-03-16 Procédé de préparation d'un film de graphène poreux, film de graphène poreux, et électrode WO2022218088A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202110390441.7 2021-04-12
CN202110390441.7A CN113096973B (zh) 2021-04-12 2021-04-12 用于制备多孔石墨烯膜的方法、多孔石墨烯膜和电极

Publications (1)

Publication Number Publication Date
WO2022218088A1 true WO2022218088A1 (fr) 2022-10-20

Family

ID=76676273

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2022/081128 WO2022218088A1 (fr) 2021-04-12 2022-03-16 Procédé de préparation d'un film de graphène poreux, film de graphène poreux, et électrode

Country Status (2)

Country Link
CN (1) CN113096973B (fr)
WO (1) WO2022218088A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113096973B (zh) * 2021-04-12 2024-05-10 王晓京 用于制备多孔石墨烯膜的方法、多孔石墨烯膜和电极
CN113725011B (zh) * 2021-08-30 2022-03-11 广东工业大学 一种电致图案化石墨烯电极的制备方法及其装置
CN115849349A (zh) * 2022-12-15 2023-03-28 上海利物盛纳米科技有限公司 一种制备高导热石墨烯散热膜的方法

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103738952A (zh) * 2013-12-16 2014-04-23 湖南大学 一种还原氧化石墨烯的方法
US20150118572A1 (en) * 2013-10-29 2015-04-30 Battery Energy Storage Systems-Technologies Solid-state battery and methods of fabrication
CN109292765A (zh) * 2018-12-07 2019-02-01 四川聚创石墨烯科技有限公司 一种制备低层数还原氧化石墨烯的方法
CN109368630A (zh) * 2018-12-07 2019-02-22 四川聚创石墨烯科技有限公司 一种用于石墨烯形成的系统
CN109437162A (zh) * 2018-12-07 2019-03-08 四川聚创石墨烯科技有限公司 一种生产还原氧化石墨烯的方法
CN109873120A (zh) * 2017-12-05 2019-06-11 中国科学院大连化学物理研究所 无金属集流体、自支撑石墨烯基锂硫电池正极的制备方法
WO2020172702A1 (fr) * 2019-02-25 2020-09-03 Swinburne University Of Technology Supercondensateurs et électrodes à base d'oxyde de graphène réduit
CN111943178A (zh) * 2020-08-21 2020-11-17 伊诺福科光学技术有限公司 一种自给自足还原制备石墨烯材料的方法、石墨烯材料、石墨烯薄膜、电极和电容器
CN113096973A (zh) * 2021-04-12 2021-07-09 王晓京 用于制备多孔石墨烯膜的方法、多孔石墨烯膜和电极
CN113354856A (zh) * 2021-06-21 2021-09-07 深圳市恒康泰医疗科技有限公司 一种石墨烯磷烯复合芯片的制备方法

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2017320331B2 (en) * 2016-08-30 2022-08-11 Royal Melbourne Institute Of Technology Capacitors, electrodes, reduced graphene oxide and methods and apparatuses of manufacture

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150118572A1 (en) * 2013-10-29 2015-04-30 Battery Energy Storage Systems-Technologies Solid-state battery and methods of fabrication
CN103738952A (zh) * 2013-12-16 2014-04-23 湖南大学 一种还原氧化石墨烯的方法
CN109873120A (zh) * 2017-12-05 2019-06-11 中国科学院大连化学物理研究所 无金属集流体、自支撑石墨烯基锂硫电池正极的制备方法
CN109292765A (zh) * 2018-12-07 2019-02-01 四川聚创石墨烯科技有限公司 一种制备低层数还原氧化石墨烯的方法
CN109368630A (zh) * 2018-12-07 2019-02-22 四川聚创石墨烯科技有限公司 一种用于石墨烯形成的系统
CN109437162A (zh) * 2018-12-07 2019-03-08 四川聚创石墨烯科技有限公司 一种生产还原氧化石墨烯的方法
WO2020172702A1 (fr) * 2019-02-25 2020-09-03 Swinburne University Of Technology Supercondensateurs et électrodes à base d'oxyde de graphène réduit
CN111943178A (zh) * 2020-08-21 2020-11-17 伊诺福科光学技术有限公司 一种自给自足还原制备石墨烯材料的方法、石墨烯材料、石墨烯薄膜、电极和电容器
CN113096973A (zh) * 2021-04-12 2021-07-09 王晓京 用于制备多孔石墨烯膜的方法、多孔石墨烯膜和电极
CN113354856A (zh) * 2021-06-21 2021-09-07 深圳市恒康泰医疗科技有限公司 一种石墨烯磷烯复合芯片的制备方法

Also Published As

Publication number Publication date
CN113096973A (zh) 2021-07-09
CN113096973B (zh) 2024-05-10

Similar Documents

Publication Publication Date Title
WO2022218088A1 (fr) Procédé de préparation d'un film de graphène poreux, film de graphène poreux, et électrode
Ghosh et al. Development of a 3D graphene aerogel and 3D porous graphene/MnO 2@ polyaniline hybrid film for all-solid-state flexible asymmetric supercapacitors
Xu et al. Flexible MXene–graphene electrodes with high volumetric capacitance for integrated co-cathode energy conversion/storage devices
US11370665B2 (en) Method for producing activated carbon
Mohanapriya et al. Solar light reduced Graphene as high energy density supercapacitor and capacitive deionization electrode
Bandyopadhyay et al. Graphitic carbon nitride modified graphene/NiAl layered double hydroxide and 3D functionalized graphene for solid-state asymmetric supercapacitors
WO2022037438A1 (fr) Procédé de préparation d'un matériau de graphène par réduction autosuffisante, matériau de graphène, film de graphène, électrode, et condensateur
Umezawa et al. Supercapacitor electrode with high charge density based on boron-doped porous carbon derived from covalent organic frameworks
Han et al. Heteroatoms (O, N)-doped porous carbon derived from bamboo shoots shells for high performance supercapacitors
Zhang et al. Large‐Scale Production of Nanographene Sheets with a Controlled Mesoporous Architecture as High‐Performance Electrochemical Electrode Materials
Barzegar et al. Synthesis of 3D porous carbon based on cheap polymers and graphene foam for high-performance electrochemical capacitors
Wang et al. Graphene's role in emerging trends of capacitive energy storage
Zhang et al. Enhanced capacitance supercapacitor electrodes from porous carbons with high mesoporous volume
WO2017219704A1 (fr) Graphème et son procédé de préparation, électrode de supercondensateur contenant le graphème, et supercondensateur
JPWO2014065241A1 (ja) グラフェン超薄片とその作製装置、作製方法、及びキャパシターとその作製方法
AU2018301683A1 (en) Simple route to highly conductive porous graphene from carbon nanodots for supercapacitor applications
Liu et al. Improved capacity of redox-active functional carbon cathodes by dimension reduction for hybrid supercapacitors
Tian et al. Preparation and electrochemical capacitance of graphene/titanium nitride nanotube array
Wei et al. Three-dimensional porous hollow microspheres of activated carbon for high-performance electrical double-layer capacitors
Wang et al. Rational synthesis of porous carbon nanocages and their potential application in high rate supercapacitors
Sawant et al. Advances in chemical and biomass-derived graphene/graphene-like nanomaterials for supercapacitors
Yang et al. Coupled ultrasonication-milling synthesis of hierarchically porous carbon for high-performance supercapacitor
Dou et al. Flexible free-standing graphene-like film electrode for supercapacitors by electrophoretic deposition and electrochemical reduction
Gorenskaia et al. Hydrothermal synthesis of N-doped graphene for supercapacitor electrodes
KR101451354B1 (ko) 독립형 탄소나노튜브/금속 산화물 입자 복합체 필름 및 그 제조방법

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: 22787317

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: 22787317

Country of ref document: EP

Kind code of ref document: A1