Flash evaporation Joule heating synthesis method and composition thereof

Abstract

The present invention relates to a method for synthesizing graphene, and more particularly, to a method for synthesizing graphene by flash Joule heating (FJH). Such methods may be used to synthesize disordered graphene in large volumes, including low-defect disordered graphene. Such methods may further be used in the synthesis of composite materials and 2D materials.

Description

[0001] This application is a divisional application of the Chinese patent application (PCT / US2019 / 047967) with an application date of August 23, 2019, application number 201980067945.6, and invention name “Flash Joule Heating Synthesis Method and Composition Thereof”.

[0002] Cross-references to related patent applications

[0003] This application claims priority to U.S. Patent Application Serial No. 62 / 727,510 filed on September 5, 2018 and U.S. Patent Application Serial No. 62 / 880,482 filed on July 30, 2019, each entitled "Subsecond Graphene Synthesis by Flash Joule Heating," which are commonly owned by the owner of the present invention. These patent applications are incorporated herein in their entirety. Technical Field

[0004] The present invention relates to methods for synthesizing graphene and other materials, and more particularly to methods for bulk synthesis of turbostratic graphene and other materials by flash Joule heating (FJH).

[0005] Government interests

[0006] This invention was made with government support under Grant No. FA9550-14-1-0111 awarded by the U.S. Department of Defense / Air Force Office of Scientific Research. The U.S. Government has certain rights in this invention. Background of the Invention

[0008] Most bulk-scale graphene is produced by exfoliation of graphite via a top-down approach, often requiring large amounts of solvent and high-energy mixing, shearing, sonication, or electrochemical treatment [Allen 2009; Yi 2015; Hernandez 2008]. This provides AB-stacked graphene in which there is a high degree of alignment order between the graphene layers. Although chemical oxidation of graphite to graphene oxide facilitates exfoliation, it requires harsh oxidants and leaves defective perforated structures in the graphene upon subsequent reduction steps [Hernandez 2008; Eda 2008]. The bottom-up synthesis of high-quality graphene is often limited to ultra-small quantities if performed by chemical vapor deposition or advanced synthetic organic methods, or it provides structures riddled with defects if performed in bulk solution. Eda 2008; Li 2008]. Therefore, there is a need for an improved method for synthesizing graphene and other materials. Summary of the invention

[0009] It has been found that flash Joule heating (FJH) of many inexpensive carbon sources such as coal, petroleum coke, biochar, carbon black, discarded food, rubber tires, and mixed plastic waste can provide gram quantities of graphene in less than 1 second. The graphene is called "flash graphene" ("FG"). The method does not use a furnace and does not use solvents or reactive gases. The yield depends on the carbon content of the source; if a high carbon source is used, the yield can be 80-90%, and the carbon purity is greater than 99%. By Raman spectroscopy, FG exhibits low intensity or absence of D bands, and I 2D / G Reaching greater than 10 and sometimes even 17, this makes FG the lowest defect graphene reported to date. FG has been observed by Raman analysis to be turbostratic, meaning that there is little order between the graphene layers, thereby facilitating its rapid exfoliation by mixing during composite formation; such rapid exfoliation cannot be accomplished by the more common AB-stacked graphene. The turbostratic nature of FG distinguishes it from most other forms of bulk graphene synthesis that produce AB-stacked graphene. FG is particularly attractive because mixed plastic waste can be converted into single-component graphene, and discarded food waste can be turned into fixed carbon FG instead of carbon dioxide and methane in landfills. The electrical energy cost of FG synthesis is only about 7.2 kJ·g -1 This makes FG suitable for bulk composites of plastics, metals, paints, concrete and other building materials. Its turbostratic nature promotes good dispersion of FG in this wide range of composites and solvents.

[0010] In addition, 2D materials can be prepared by applying voltage pulses (i.e. flash Joule heating) across respective precursors. The present invention further encompasses a method for synthesizing different types of 2D materials on a millisecond time scale, and the cost of this method is very low. Compared with other methods such as chemical vapor deposition (CVD) and hydrothermal methods, higher yields can be obtained in a much shorter period of time, and no solvents need to be used in the process (which is obviously more economical). The voltage pulse method is very short, which makes it possible to synthesize some metastable forms of 2D materials that are very difficult to synthesize by other methods, such as 1T'-MoS2 and black phosphorus.

[0011] In general, in one embodiment, the invention features a method that includes synthesizing graphene by applying a voltage pulse across a conductive carbon source that is not substantially graphene.

[0012] Embodiments of the invention may include one or more of the following features:

[0013] The conductivity of the conductive carbon source can be greater than 10 -5 S / cm.

[0014] The conductivity of the conductive carbon source can be greater than 10-3 S / cm.

[0015] The duration of the voltage pulse may be from 1 microsecond to 5 seconds.

[0016] The duration of the voltage pulse may be 100 to 500 milliseconds.

[0017] The voltage pulse may be repeated 2 to 100 times.

[0018] The voltage pulse may be repeated 2 to 10 times.

[0019] The current across the sample may be 0.01A / cm 2 Up to 10000A / cm 2 .

[0020] The current across the sample may be 0.1A / cm 2 Up to 1000A / cm 2 .

[0021] The voltage across the sample can be from 10 V / cm to 4000 V / cm.

[0022] The voltage across the sample may be from 100 V / cm to 400 V / cm.

[0023] The conductive carbon source may be selected from anthracite, biochar treated at a relatively high temperature, calcined petroleum coke, shungite, carbon nanotubes, asphaltene, acetylene black, carbon black and mixtures thereof.

[0024] The conductive carbon source may include a conductive carbon source additive that imparts sufficient conductivity to the conductive carbon source for use in the method.

[0025] The conductive carbon source additive can be selected from anthracite, biochar treated at a relatively high temperature, calcined petroleum coke, carbon nanotubes, graphene quantum dots, acetylene black, carbon black, shungite, graphene or a mixture thereof. The conductive carbon source can be a relatively low conductivity carbon material selected from feces, plastics, vinyl polymers, condensation polymers, step-growth polymers, chain-growth polymers, active polymers, rubber, humic acid, carbohydrates, rice flour, food waste, food, coal, organic waste, organic materials, bituminous coal, coke, petroleum coke, oil, petroleum products, carbon after non-carbon atoms are removed from natural gas or oil or carbon dioxide, wood, cellulose, leaves, branches, grass, biomass, animal carcasses, fish carcasses, proteins and mixtures thereof. The conductive carbon source additive can be added to the relatively low conductivity carbon material so that the relatively low conductivity source has sufficient conductivity for use in the method.

[0026] Prior to the method, the conductive carbon source may comprise less than 50% graphene.

[0027] Prior to the method, the conductive carbon source may be substantially free of spectroscopically detectable graphene.

[0028] The product yield of the method may include at least 70% graphene.

[0029] The product yield may be at least 90% graphene.

[0030] The product yield may be 100% graphene.

[0031] The synthesized graphene may be turbostratic graphene.

[0032] The conductive carbon source may include a conductive carbon source having a conductivity of at most 10 -7 S / cm. The conductive carbon source may further include a conductive carbon source additive intermixed with the carbon source. The conductivity of the conductive carbon source may be at least 10 -5 S / cm.

[0033] The conductivity of the conductive carbon source may be at least 10 -3 S / cm.

[0034] The conductive carbon source additive may be selected from carbon black, metal powder and combinations thereof.

[0035] The process may be a continuous process.

[0036] The method may be an automated method.

[0037] The conductive carbon source may include carbon black and rubber.

[0038] The conductive carbon source may include 1 wt % to 10 wt % of carbon black.

[0039] The conductive carbon source may include 4 wt % to 6 wt % of carbon black.

[0040] The step of applying a voltage pulse may use a DC voltage.

[0041] The step of applying a voltage pulse may use an AC voltage.

[0042] The voltage pulses may be applied using a power supply using three-phase electrical power.

[0043] In general, in another embodiment, the invention features a method that includes synthesizing graphene by applying a voltage pulse across a conductive carbon source that is not substantially graphene. When the voltage pulse is applied across the conductive carbon source, heteroatoms are present to provide a doped or heteroatom-containing graphene product.

[0044] Embodiments of the invention may include one or more of the following features:

[0045] The heteroatom may be selected from nitrogen, phosphorus, boron and mixtures thereof.

[0046] The heteroatom may be selected from metals, semimetals and mixtures thereof.

[0047] The heteroatom source may be selected from melamine, aminoborane, melamine-formaldehyde resin, phosphine, phosphate, metal salt, metal oxide and mixtures thereof.

[0048] In general, in another embodiment, the invention features an apparatus that includes a carbon feedstock. The carbon feedstock includes a conductive carbon source that is substantially not graphene. The apparatus further includes a non-conductive container operable to confine the conductive carbon source. The apparatus further includes an electrode operable to apply a voltage pulse across the conductive carbon source within the non-conductive container to synthesize graphene.

[0049] Embodiments of the invention may include one or more of the following features:

[0050] The apparatus may further include a conduit through which the conductive carbon source may be transported to the non-conductive container.

[0051] The apparatus may further include a chamber, and the non-conductive container may be located within the chamber when the electrode applies the voltage pulse.

[0052] The non-conductive container may include quartz or ceramic material.

[0053] The non-conductive container may include a quartz tube.

[0054] The apparatus may include a plurality of the non-conductive containers. The apparatus may further include a belt or screw and a collection box. After the conductive carbon source is filled in the non-conductive container, the belt or screw may be operable to transport a container of the plurality of the non-conductive containers into the chamber. The belt or screw may further be operable to transport the non-conductive container out of the chamber to a location where the synthesized graphene can be collected in a collection box.

[0055] The apparatus may include a plurality of capacitors operable to apply a voltage pulse.

[0056] The apparatus may include a controller and a mechanical relay operable to control the application of the voltage pulses.

[0057] The apparatus may include an inductor and a diode operably connected to a controller and a mechanical relay.

[0058] The apparatus may further comprise a disconnect switch.

[0059] The conductive carbon source may include a conductive carbon source having a conductivity of at least 10 -5 S / cm of carbon source.

[0060] The conductivity of the carbon source may be at least 10 -3 S / cm.

[0061] The conductive carbon source may include a carbon source and a conductive carbon source additive.

[0062] The conductive carbon source may be carbon powder.

[0063] The conductivity of the carbon source may be at least 10 -6 S / cm. The conductivity of the conductive carbon source may be at least 10 -5 S / cm.

[0064] The conductivity of the conductive carbon source may be at least 10 -3 S / cm.

[0065] The apparatus may be operable to carry out a continuous process for synthesizing graphene from the conductive carbon source.

[0066] The apparatus may be operable to perform an automated method of synthesizing graphene from the conductive carbon source.

[0067] In general, in another embodiment, the invention features a system that includes the apparatus described above.

[0068] Embodiments of the invention may include one or more of the following features:

[0069] The device may be operably connected to a DC voltage source.

[0070] The device may be operably connected to a source of AC voltage.

[0071] The device may be operably connected to a power source using three-phase electrical power.

[0072] The power supply may use three-phase electrical power followed by full-wave rectification.

[0073] The power supply may use a zero-crossing relay to control the duration of the voltage pulse.

[0074] The power supply may further comprise a computer control.The computer control may be operable to select the duration of the voltage pulse based on the number of half cycles allowed through the zero crossing relay.

[0075] The power supply may be operable to use one of 120, 208, 277, 480 volts AC (RMS) three phase.

[0076] The power source may include a three-phase generator operable to provide AC power.

[0077] The three-phase generator may be mechanically coupled to an AC motor.

[0078] The three-phase generator may include a rotor.The three-phase generator may be operable to provide AC power by rapidly converting mechanical power into electric current due to the inertia of the rotor.

[0079] The three-phase generator may include a flywheel.The three-phase generator may be operable to provide AC power using a flywheel to provide a longer duration and stable voltage and current output.

[0080] The apparatus may include a plurality of capacitors operable to apply a voltage pulse.The apparatus may include a controller and a mechanical relay operable to control the application of the voltage pulse.

[0081] The apparatus may include an inductor and a diode operatively connected to a controller and a mechanical relay.

[0082] The apparatus may further comprise a disconnect switch.

[0083] In general, in another embodiment, the invention features a method of forming a 2D material. The method includes selecting a precursor material including a precursor. The method further includes applying a voltage pulse across the material to form the 2D material.

[0084] Embodiments of the invention may include one or more of the following features:

[0085] The conductivity of the precursor may be greater than 10 -6 S / cm.

[0086] The precursor may include a metal source.

[0087] The metal source may be selected from iron powder, molybdenum powder, tungsten metal and copper metal.

[0088] The precursor may include a non-metallic source.

[0089] The non-metal source may be selected from carbon black, calcined petroleum coke.

[0090] The conductivity of the precursor may be less than 10 -6 S / cm. The precursor material may further include a conductive source. The conductivity of the precursor material may be greater than 10 -5 S / cm.

[0091] The conductivity of the precursor may be less than 10 -7 S / cm.

[0092] The precursor may be selected from molybdenum disulfide (MoS2), ammonium tetrathiomolybdate ((NH4)2MoS4), borane ammonia complex (BH3NH3), red phosphorus, and combinations thereof.

[0093] The conductive source may be selected from carbon materials, metal powders and combinations thereof.

[0094] The precursor may be selected from molybdenum disulfide (MoS2), ammonium tetrathiomolybdate ((NH4)2MoS4), borane ammonia complex (BH3NH3), red phosphorus, and combinations thereof.

[0095] The precursor may include molybdenum disulfide (MoS2) or ammonium tetrathiomolybdate ((NH4)2MoS4).

[0096] The 2D material may include 1T'-MoS2 and 2H-MoS2.

[0097] The precursor may include borane ammonia complex (BH3NH3).

[0098] The 2D material may include hexagonal boron nitride (h-BN).

[0099] The precursor may include red phosphorus.

[0100] The 2D material may include black phosphorus.

[0101] The step of applying a voltage pulse across the material to form a 2D material may include applying a number of voltage pulses across the material. The number of voltage pulses may be 1 pulse to 100 pulses. The step of applying a voltage pulse across the material to form a 2D material may include a duration of each voltage pulse of 1 microsecond to 5 seconds. The step of applying a voltage pulse across the material to form a 2D material may include a current of each voltage pulse of 0.01A / cm 2 Up to 10000A / cm 2 The step of applying voltage pulses across the material to form the 2D material may include each voltage pulse having a voltage of 10V to 4000V.

[0102] The number of the voltage pulses may be 1 pulse to 10 pulses. The duration of each voltage pulse may be 10 microseconds to 1000 milliseconds. The current of each voltage pulse may be 0.1A / cm 2 Up to 1000A / cm 2 The voltage of each voltage pulse may be 100V to 400V.

[0103] The step of applying a voltage pulse may use a DC voltage.

[0104] The step of applying a voltage pulse may use an AC voltage.

[0105] The voltage pulses may be applied using a power supply using three-phase electrical power.

[0106] In general, in another embodiment, the invention features an apparatus comprising: a precursor material comprising a precursor. The apparatus further comprises a non-conductive container operable to confine the precursor material. The apparatus further comprises an electrode operable to apply a voltage pulse across the precursor material within the non-conductive container to prepare a 2D material.

[0107] Embodiments of the invention may include one or more of the following features:

[0108] The apparatus may further comprise a conduit through which the precursor may be delivered to the non-conductive container.

[0109] The apparatus may further comprise a chamber in which the non-conductive container may be located when the electrode applies the voltage pulse.

[0110] The non-conductive container may include quartz or ceramic material.

[0111] The apparatus may include a plurality of the non-conductive containers. The apparatus may further include a belt or screw and a collection box. After the precursor material is filled in the non-conductive container, the belt or screw may be operable to transport a non-conductive container from the plurality of the non-conductive containers into the chamber. The belt or screw may further be operable to transport the non-conductive container out of the chamber to a position where the prepared 2D material can be collected in a collection box.

[0112] The apparatus may include a plurality of capacitors operable to apply a voltage pulse.

[0113] The apparatus may include a controller and a mechanical relay operable to control the application of the voltage pulses.

[0114] The apparatus may include an inductor and a diode operatively connected to a controller and a mechanical relay.

[0115] The apparatus may further comprise a disconnect switch.

[0116] The conductivity of the precursor may be at least 10 -5 S / cm.

[0117] The conductivity of the precursor may be at least 10 -3 S / cm.

[0118] The precursor material may further include a conductive source.

[0119] The conductivity of the precursor may be at least at most 10 -6 S / cm. The conductivity of the conductive source may be at least 10 -5 S / cm.

[0120] The electrical conductivity of the precursor material may be at least 10 -3 S / cm.

[0121] The apparatus may be operable to carry out a continuous method of producing a 2D material from the precursor material.

[0122] The apparatus may be operable to perform an automated method of producing a 2D material from the precursor material.

[0123] In general, in another embodiment, the invention features a system that includes the apparatus described above.

[0124] Embodiments of the invention may include one or more of the following features:

[0125] The device may be operably connected to a DC voltage source.

[0126] The device may be operably connected to a source of AC voltage.

[0127] The device may be operably connected to a power source using three-phase electrical power.

[0128] The power supply may use three-phase electrical power followed by full-wave rectification.

[0129] The power supply may use a zero-crossing relay to control the duration of the voltage pulse.

[0130] The power supply may further comprise a computer control.The computer control may be operable to select the duration of the voltage pulse based on the number of half cycles allowed through the zero crossing relay.

[0131] The power supply may be operable to use one of 120, 208, 277, 480 volts AC (RMS) three phase.

[0132] The power source may include a three-phase generator operable to provide AC power.

[0133] The three-phase generator may be mechanically coupled to an AC motor.

[0134] The three-phase generator may include a rotor.The three-phase generator may be operable to provide AC power by rapidly converting mechanical power into electric current due to the inertia of the rotor.

[0135] The three-phase generator may include a flywheel.The three-phase generator may be operable to provide AC power using a flywheel to provide a longer duration and stable voltage and current output.

[0136] The apparatus may include a plurality of capacitors operable to apply a voltage pulse.The apparatus may include a controller operable to control the application of the voltage pulse and a mechanical relay.

[0137] The apparatus may include an inductor and a diode operatively connected to a controller and a mechanical relay.

[0138] The apparatus may further comprise a disconnect switch.

[0139] In general, in another embodiment, the invention features a method that includes synthesizing bulk quantities of turbostratic graphene.

[0140] Embodiments of the invention may include one or more of the following features:

[0141] The method may include a flash graphene process to produce turbostratic graphene from a carbon-based material.

[0142] The turbostratic graphene may be low-defect turbostratic graphene.

[0143] The method may further include using the turbostratic graphene to make a composite material.

[0144] In general, in another embodiment, the invention features a method that includes synthesizing turbostratic graphene by applying a voltage pulse across a conductive carbon source that is not substantially graphene.

[0145] Embodiments of the invention may include one or more of the following features:

[0146] The conductivity of the conductive carbon source can be greater than 10 -5 S / cm.

[0147] The conductivity of the conductive carbon source can be greater than 10 -3 S / cm.

[0148] The duration of the voltage pulse may be from 1 microsecond to 5 seconds.

[0149] The duration of the voltage pulse may be 100 to 500 milliseconds.

[0150] The voltage pulse may be repeated 2 to 100 times.

[0151] The voltage pulse may be repeated 2 to 10 times.

[0152] The current across the sample may be 0.01A / cm 2 Up to 10000A / cm 2 .

[0153] The current across the sample may be 0.1A / cm 2 Up to 1000A / cm 2 .

[0154] The voltage across the sample can be from 10 V / cm to 4000 V / cm.

[0155] The voltage across the sample may be from 100 V / cm to 400 V / cm.

[0156] The conductive carbon source may be selected from anthracite, biochar treated at a relatively high temperature, calcined petroleum coke, shungite, carbon nanotubes, asphaltene, acetylene black, carbon black and mixtures thereof.

[0157] The conductive carbon source may include a conductive carbon source additive that imparts sufficient conductivity to the conductive carbon source for use in the method.

[0158] The conductive carbon source additive can be selected from anthracite, biochar treated at a relatively high temperature, calcined petroleum coke, carbon nanotubes, graphene quantum dots, acetylene black, carbon black, shungite, graphene or a mixture thereof. The conductive carbon source can be a relatively low conductivity carbon material selected from feces, plastics, vinyl polymers, condensation polymers, step-growth polymers, chain-growth polymers, active polymers, rubber, humic acid, carbohydrates, rice flour, food waste, food, coal, organic waste, organic materials, bituminous coal, coke, petroleum coke, petroleum, petroleum products, carbon after non-carbon atoms are removed from natural gas or petroleum or carbon dioxide, wood, cellulose, leaves, branches, grass, biomass, animal carcasses, fish carcasses, proteins and mixtures thereof. The conductive carbon source additive can be added to the relatively low conductivity carbon material so that the relatively low conductivity source has sufficient conductivity for use in the method.

[0159] The conductive carbon source may include a conductivity of at most 10 -7 S / cm. The conductive carbon source may further include a conductive carbon source additive intermixed with the carbon source. The conductivity of the conductive carbon source may be at least 10 -5 S / cm.

[0160] The conductivity of the conductive carbon source may be at least 10 -3 S / cm.

[0161] The conductive carbon source additive may be selected from carbon black, metal powder and combinations thereof.

[0162] The process may be a continuous process.

[0163] The method may be an automated method.

[0164] The method may synthesize at least 1 g of bulk graphene material. The turbostratic graphene may be at least 90 wt % of the bulk graphene material.

[0165] In general, in another embodiment, the invention features a bulk graphene material. A majority of the bulk graphene material is turbostratic graphene. The bulk graphene material weighs at least 1 g.

[0166] Embodiments of the invention may include one or more of the following features:

[0167] At least 90 wt% of the graphene may be turbostratic graphene.

[0168] The bulk graphene material can be synthesized from a carbon source material mainly comprising a solid carbon source. The solid carbon source is a solid carbon source.

[0169] The solid carbon source may comprise at least 90 wt % of the carbon source material.

[0170] The bulk graphene material can be synthesized from a carbon source material mainly comprising a liquid carbon source. The liquid carbon source is a liquid carbon source.

[0171] The liquid carbon source may account for at least 90 wt % of the carbon source material.

[0172] In general, in another embodiment, the invention features a composite material that includes turbostratic graphene and a second material.

[0173] Embodiments of the invention may include one or more of the following features:

[0174] The second material can be selected from concrete, cement, plastic, paint, coating, foam, polyurethane foam, flooring material, roofing material, wood, plywood, aluminum, steel, copper, metal, asphalt, metal oxide, carbon-carbon composites, fiber, membrane and combinations thereof.

[0175] The composite material may include 0.001 wt % to 10 wt % of the turbostratic graphene.

[0176] The composite material may have a tensile strength greater than a tensile strength of the second material without the turbostratic graphene.

[0177] The composite material may have a tensile strength at least 10% greater than a tensile strength of the second material without the turbostratic graphene.

[0178] The compressive strength of the composite material is greater than the compressive strength of the second material without the turbostratic graphene.

[0179] The compressive strength of the composite material may be at least 10% greater than the compressive strength of the second material without the turbostratic graphene.

[0180] The Young's modulus of the composite material may be substantially different from the Young's modulus of the second material without the turbostratic graphene.

[0181] The Young's modulus of the composite material may differ by at least 10% from the Young's modulus of the second material without the turbostratic graphene.

[0182] The yield strength of the composite material may be greater than the yield strength of the second material without the turbostratic graphene.

[0183] The yield strength of the composite material may be at least 10% greater than the yield strength of the second material without the turbostratic graphene.

[0184] The electrical conductivity of the composite material may be greater than the electrical conductivity of the second material without the turbostratic graphene.

[0185] The electrical conductivity of the composite material may be at least 10 Siemens / cm greater than the electrical conductivity of the second material without the turbostratic graphene.

[0186] The thermal conductivity of the composite material may be greater than the thermal conductivity of the second material without the turbostratic graphene.

[0187] The thermal conductivity of the composite material may be at least 1 Watt / meter-Kelvin higher than the thermal conductivity of the second material without the turbostratic graphene.

[0188] The second material may be a liquid material.

[0189] The liquid material may be selected from the group consisting of coolant, transmission fluid, lubricant, oil, and combinations thereof.

[0190] The liquid material may be selected from drilling fluid and fracturing fluid.

[0191] The turbostratic graphene may be a fluid loss prevention additive for liquid materials.

[0192] The viscosity of the composite material may be at least 1 mPa-s greater than the viscosity of the liquid material without the turbostratic graphene.

[0193] The second material may be a dry lubricant.

[0194] In general, in another embodiment, the invention features a dry lubricant that includes turbostratic graphene.

[0195] Embodiments of the invention may include one or more of the following features:

[0196] The dry lubricant may be the turbostratic graphene.

[0197] In general, in another embodiment, the invention features a composition of low-defect turbostratic graphene.

[0198] Embodiments of the invention may include one or more of the following features:

[0199] The turbostratic graphene comprises a plurality of graphene sheets. The graphene sheets mainly comprise sp 2 Hybridized carbon atoms.

[0200] The graphene sheet may include at least 70 atomic % sp 2 Hybridized carbon atoms.

[0201] In general, in another embodiment, the invention features a method that includes chemical covalent functionalization of turbostratic graphene. The functionalized atom is selected from the group consisting of oxygen, carbon, metal, sulfur, phosphorus, non-metal, metalloid, and combinations thereof.

[0202] In general, in another embodiment, the invention features a method that includes chemical non-covalent functionalization of turbostratic graphene by one or more of the following: surfactants, DNA, proteins, polymers, aromatic compounds, small organic molecules, gases, groundwater contaminants, biological cells, microorganisms, polychlorinated biphenyls, perchlorates, and borates.

[0203] In general, in another embodiment, the invention features a method that includes selecting a material that includes turbostratic graphene. The method further includes using the material as a scaling inhibitor or as a corrosion inhibitor.

[0204] Embodiments of the invention may include one or more of the following features:

[0205] The material may be the turbostratic graphene.

[0206] In general, in another embodiment, the invention features a sensor device that includes turbostratic graphene. The turbostratic graphene can be operable in the sensor device to change an electrical property based on adsorption of an analyte.

[0207] Embodiments of the invention may include one or more of the following features:

[0208] The electrical property may be selected from the group consisting of mobility, resistance, conductance, and combinations thereof.

[0209] The analyte may be selected from the group consisting of a gas, a biological agent, a neural agent, and combinations thereof.

[0210] In general, in another embodiment, the invention features a device including turbostratic graphene. The device is selected from an optical device, an optoelectronic device, and a device operable for field emission of electrons or photons. BRIEF DESCRIPTION OF THE DRAWINGS

[0211] Figures 1A-1F FG synthesized from various carbon sources is shown. Figure 1A is a schematic diagram of the FJH method. Figure 1B-1D is a HR-TEM image of a single layer of FG derived from coffee on top of carbon black, which has 2 nm, and Scale of. Figure 1E Characterized by including Raman spectra (showing the best and representative spectra obtained), XRD spectra and TEM images of FG obtained from various carbon sources. Each pixel in the Raman map is 2 μm, and a 50× magnification is used. The scale bars in the TEM images are 5, 200, 5 and 100 nm from top to bottom, respectively. Figure 1F is a graph showing the temperature rise during flash evaporation versus time.

[0212] Figure 2A -2D shows the FJH system. Figure 2A is an electrical schematic diagram of the FJH system. Figure 2B Here is a photo of the FJH system mounted on a plastic cart. Figure 2C The sample holder was made from a small commercial vise (Amazon) and laser-cut wooden parts. Figure 2D shows the Figure 2A Capacitors in the FJH system.

[0213] Figures 3A-3D is a graph of BET surface area analysis of CB-FG.

[0214] Figure 4 Raman spectra of FG obtained from other carbon sources are shown.

[0215] Figure 5A-5G The FJH critical parameters are shown. Figure 5A is the Raman spectrum of CB-FG with increasing flash voltage. Figure 5B CB-FG I at different flash voltages 2D / G and I D / G Summary of ratios. Figure 5C It is the time-temperature diagram of CB-FG reacted under different conditions.

[0216] Figure 5D is the time-temperature diagram of CB-FG reacted at different flash durations. Figure 5E are the Raman spectra of CB-FG with different compression ratios. Fig. 5F is Figure 5C Raman spectra of CB-FG at different flash temperatures. Figure 5G is Figure 5D Raman spectra of CB-FG at different flash durations.

[0217] Figures 6A-6C Ultrafast temperature measurements are shown. Fig. 6A is a schematic diagram of the temperature measurement device. Figure 6B The blackbody radiation of the sample collected by an optical fiber through a custom-made grating black box is shown. Figure 6C is a graph showing the blackbody radiation fit.

[0218] Figures 7A-7F is the XPS of calcined petroleum coke, pretreated coffee and carbon black before and after the FJH process.

[0219] Figures 8A-8D is the TGA of the following in air: Fig. 8A ) Crude CB (Black Pearls 2000, Cabot) and CB-FG; ( Figure 8B ) Coarse anthracite and anthracite-FG; ( Figure 8C ) crude calcined coke and CC-FG; and ( Fig.8D )Pretreated coffee and coffee-FG.

[0220] Fig. 8E Is from Fig.8D Raman spectrum of the TGA-residue of coffee-FG.

[0221] Figures 9A-9G It is shown that the temperature range (1500-5000K) is very close to the temperature at which the -9 s, Molecular dynamics (MD) simulations of structures with various properties (e.g., microporosity, misalignment, and size of graphitic domains) held in an NVT thermostat. Scale bar is 1.5 nm.

[0222] Figures 10A-10B are the graphene lattice pairs ( Fig. 10A )AB stacking order and ( Fig. 10B ) Illustration of non-AB stacking or turbostratification.

[0223] Fig.11 is a graph of the Raman spectrum of flash graphene from carbon black (CB), which shows turbostratic peaks.

[0224] Figures 12A-12B is a plot of the 2D peaks in the Raman spectrum of flash graphene from carbon black (CB).

[0225] Figures 13A-13E The scale-up and application of CB-FG are shown. Fig.13A FJH quartz tubes of different sizes and shapes are shown providing the FG. Fig. 13B is a graph showing a FG dispersion (1%) in water / Pluronic (F-127). Fig. 13C It shows that at 5g·L -1 FG dispersions in various organic solvents at concentrations of . Fig.13D is a graph of the mechanical properties of cement compounded with FG. Fig.13E After centrifugation, 4 g·L -1 of( Fig. 13B CB-FG and 10 g·L after centrifugation -1 Photo of commercial samples. Fig.13A , 13C The scale bar in 13E is 1 cm.

[0226] Fig.14 is an automated implementation for the FG method.

[0227] Fig.15 is a graphical representation of three sine waves of three-phase power that may be used in one embodiment of the present invention.

[0228] Fig.16 is a diagram showing the three phases of FG enlarged in scale.

[0229] Fig.17 Illustration of the flash graphene pulse formed by three-phase power.

[0230] Fig.18 is a diagram showing one implementation of a scaled-up three-phase FG that has directly controlled all three zero-crossing relays.

[0231] Fig.19 is a graph showing time-temperature for various graphene synthesis methods.

[0232] Figures 20A-20B is the SEM image of cement and CB-FG composites.

[0233] Fig.21 is a graph showing the compressive strength of PDMS, CB-FG / PDMS composite, and CB / PDMS composite.

[0234] Figures 22A-22His a diagram showing FG in a Li ion capacitor and a Li ion battery. A Li ion battery was manufactured and cycled, then opened, and a Li ion capacitor was manufactured using the anode and cathode.

[0235] Fig.23A is the Raman spectrum of CB-rubber FG.

[0236] Fig. 23B It is the Raman map of CB-rubber FG.

[0237] Fig.24A 3XRD of 5% CB-rubber FG, 5% CB-rubber (200 ms) FG, 5% CB-rubber (300 ms) FG and 5% CB-rubber (400 ms) FG.

[0238] Fig. 24B These are the Raman spectra of 5% CB-rubber FG, 5% CB-rubber (200 ms) FG, 5% CB-rubber (300 ms) FG, and 5% CB-rubber (400 ms) FG.

[0239] Fig.25A Raman spectra of flash-heated MoS2 using different flash times.

[0240] Fig.25B It is the yield of MoS2 by flash heating at different flash times.

[0241] Fig.25C J3-E at different flash times 2g Peak intensity ratio.

[0242] Fig.26 XPS Mo 3d spectra of flash-heated MoS2 using different flash times.

[0243] Fig. 27 It is the XRD of 2H-MoS2 and 1T'-MoS2.

[0244] Figures 28A-28B is a TEM image of flash-heated MoS2.

[0245] Fig.29 are the Raman spectra of flash graphene (FG) and different boron nitride (BN) samples.

[0246] Figures 30A-30B These are the XPS B 1s and N1s spectra of the boron nitride sample, respectively.

[0247] Details

[0248] The present invention is a novel method for synthesizing very high quality bulk graphene using low-cost processing equipment and materials and without solvents by flash Joule heating (FJH). The FJH can take less than 1 second. This can be amplified by repeated graphene pellet formation, in which there are hundreds of piston-shaped domains, each of which is, for example, 0.2 to 100 cm in diameter and 4 cm-1 m in length, and compressed and FJH are performed, and then the graphene pellets are ejected. It is similar to making a bulk nail, in which each nail has a piston impacting its top to form a head. Cheap sources such as renewable biochar and coke and anthracite can be used for the synthesis.

[0249] For heating, ground conductive carbon such as biochar (conductive biochar can be processed at higher temperatures (i.e., greater than 800° C.), calcined petroleum coke, asphaltene or anthracite are used as conductive carbon materials, but others can also be used. If the carbon sources are used and they have a lower conductivity than required (e.g., dog feces, cockroaches, humic acid, bituminous coal, plastics, organic waste, cellulose, protein, animal or fish carcasses), the conductivity can be improved by adding fillers such as conductive biochar, calcined coke, anthracite, asphaltene, carbon black or FG from a previous run to increase the conductivity. Of course, other carbon types such as carbon nanotubes, carbon black, acetylene black, activated carbon, organic waste, plastics, rubber and polymers can be used. The presence of non-carbon atoms does not inhibit the formation, but it can produce heteroatom-doped graphene products, depending on the percentage of heteroatoms added, their boiling or sublimation points and flash conditions.

[0250] Indeed, the conductive carbon source can be directly derived from fossil fuels (methane, natural gas, oil, etc.) or other carbons, wherein non-carbon atoms (e.g., hydrogen atoms) are stripped from the carbon. For example, fossil fuels can be used for energy without CO2 emissions involving catalytic stripping of hydrogen atoms from fossil fuels to produce solid carbon and H2 gas. The H2 formed can then be used in fuel cells to generate electricity. Solid carbon is therefore formed in very large quantities by this catalytic stripping method, which can then be used in the FJH method by obtaining the solid carbon stripped of hydrogen and converting it into FG.

[0251] The conductive carbon source used in the present invention preferably has a conductivity greater than 10 -3 S / cm, but even with 10 -5 Those with 100 S / cm can also work. For example, calcined petroleum coke (CPC), biochar, charcoal, bituminous coal, humic acid can be successfully converted into graphene as shown below.

[0252] Voltage range: 100-400V / cm.

[0253] Current range: 0.1-1000A / cm 2 .

[0254] FJH product yield range: 10%-90%.

[0255] The graphene yield in the FJH product is greater than 70%.

[0256] Flash Joule Heating Method

[0257] In the FJH process, amorphous conductive carbon powder 103 is compressed between two electrodes 102 and 104 in a quartz or ceramic tube 101. Figure 1A . ( Figure 1F is a graph showing the temperature rise versus time during the flash period). Figure 2A-2C A FJH system 200 is shown including a controlled environment 204 (also referred to as a flash chamber) having a brass screw 201, copper fleece 202, and a carbon source 203. The controlled environment 204 may be at atmospheric pressure or at a mild vacuum (-10 mm Hg) to facilitate degassing.

[0258] Components within the control environment 204 are connected to components including:

[0259] Capacitor 210, for example, 10× of 450V, 6mF aluminum electrolytic capacitors (Mouser #80-PEH 200YX460BQU2). This capacitor bank can be used for FG synthesis at a batch scale of less than or equal to 0.5g. Alternatively, capacitor 210 can be 10× of 400V, 18mF aluminum electrolytic capacitors (Mouser #80-ALS70A183QS400). This additional capacitor bank can be used for FG synthesis at a batch scale of greater than 0.5g and up to 1.0g. FIG2D shows a single capacitor in the FJH system 200.

[0260] Mechanical relay 205, for example 900V, 500A (TE Connectivity LEV200A5ANA).

[0261] Power supply 213: LED power supply 299.6W 214-428V 700mA (Mouser #709-HLG320H-C700B). Current knob 212 may have a 10kΩ potentiometer.

[0262] V cap 215, which can be measured by multimeter Fluke 189.

[0263] The discharging and charging switch breakers 211 and 214 are, for example, 400V, 6A (ABB S282K 6A), respectively.

[0264] The capacitor switch breaker 209 is, for example, 277V, 10A (ABB S201P-C10).

[0265] Disconnect switch circuit breaker 208, for example 440V, 63A (AAB S283 UC Z 63A).

[0266] The controller 216 is, for example, an Arduino Uno with an LCD display.

[0267] The inductor 206 is, for example, 24 mH (Mouser #553-C-80U).

[0268] The diode 207 is, for example, 1200V, 560A (Mouser#747-MDO500-12N1).

[0269] For safety reasons, circuit breakers can be used as switches. Circuit breakers have built-in arc suppression, which can interrupt 1000 amps or more. Conventional switches do not have such a high level of arc suppression and may burn or fuse due to high current pulses. For safety reasons, DC voltage rated circuit breakers can be used. Most AC circuit breakers have a voltage of 1 / 2 of the DC rating or less, because DC arcs are significantly more difficult to suppress. Circuit breakers designed for DC solar power systems can be used. For safety reasons, circuit breakers can be selected by a time curve of typically 0.1s rather than a steady-state current rating. K-type DC circuit breakers will have a trip current of ~10× higher at 0.1s compared to their rated current, and Z-type breakers will have a trip current of ~4× higher at 0.1s. This "delayed trip" designed in most circuit breakers will allow pulse currents much higher than the steady-state rating of the breaker. For safety reasons, a small amount of inductance may be included in the discharge circuit to limit the rise time to 1 millisecond or more. Extremely fast discharges can damage components and cause RF interference with other experimental equipment. It should also be remembered that the system can discharge thousands of joules in milliseconds, which can cause components such as relays or even capacitors to explode. These components can be encapsulated to protect both from high voltages and possible flying debris.

[0270] Additionally, for safety reasons, the control line may have an opto-isolator rated for high voltage. For safety reasons, the FJH system 201 may include a visual charge indicator (i.e., indicator light 217). A 230V clear glass incandescent bulb may be used, since the glow on the filament also provides an approximate indication of the amount of charge on the capacitor bank. (i.e., bright light means danger). For safety reasons, a trigger switch with a metal trigger is not used. If an arc is formed, the metal trigger can become live.

[0271] The FJH system 200 can be at atmospheric pressure or under a moderate vacuum (~10 mm Hg) to facilitate degassing. The electrodes can be copper, graphite, or any conductive refractory material. The high voltage electrical discharge from the capacitor bank (capacitor 210) brings the carbon source to a temperature greater than 3000K in less than 100 ms, which effectively converts amorphous carbon into FG. Figure 2B As shown, the FJH system may further include a vacuum valve 220 (for controlling the environment in the control environment 204) and a multimeter 221 (for V cap and sample resistance). Figure 2C The sample holder is made from a small commercial vise (Amazon) and laser cut wooden parts. Loose fitting (to allow gas to escape during flash) brass screws act as two electrodes that contact a copper wool plug (or graphite disk) that contacts the desired carbon source. The rubber stopper provides gradual compression of the sample while the vise is compressed to increase the conductivity of the sample. The caliper width is 5 cm.

[0272] Flash graphene

[0273] The FG produced using the FJH system 200 may have a turbostratic structure. Figure 1B-1D is a HR-TEM image of a single layer of coffee-derived FG atop carbon black. (The coffee-derived FG comes from spent coffee grounds; the smaller graphene particles within the large graphene sheets come from the carbon black conductive additive.) Figure 1B and Figure 1C In the magnified area 105 in FIG. 1 , the misoriented layers of FG and their moiré patterns can be seen. Figure 1D As shown ( Figure 1B 106), FG obtained from used coffee grounds provides hexagonal monolayer graphene.

[0274] Various materials can be used in the FJH system. Table I below reflects the FJH parameters of various materials used.

[0275] Table I

[0276]

[0277]

[0278] In Table I, "Dur" is the duration of the switch opening time, not the actual flash duration; "V Pre" is the voltage pretreatment, i.e., pretreatment without flash; and "V Flash" is the voltage flash, which is the actual flash used for FG synthesis. Voltage pretreatment is a partial coking of the material to reduce volatile materials and increase conductivity. By Raman analysis, the coking process provides only amorphous material. This voltage pretreatment can be important for starting materials with low carbon content. This pre-coking can be eliminated with beneficiation materials in which there is a preheating cycle, because industrial heating is not as expensive as using electricity when heated below certain temperatures.

[0279] High-quality graphene can be quickly identified by Raman spectroscopy. [Ferrari 2006; Ferrari 2007; Malard 2009; Ni 2009]. FG from carbon black (CB-FG) has a strong 2D peak. Figure 1E The Raman map of CB-FG shows that at many positions I 2D / G The extremely low D band indicates the low defect concentration of these FG products, which leads to the amplification of the 2D band. Therefore, the unusually high I of 17 in CB-FG 2D / G ( Figure 1E ) is the highest value reported to date for any form of graphene and is likely a result of the extreme temperatures reached in the flash method of outgassing non-carbon elements from the system.

[0280] The XRD pattern of FG shows a clear (002) peak, which indicates successful graphitization of amorphous carbon. The (002) peak of FG occurs at 2θ = 27.8°, which corresponds to The interlayer spacing (I c ). This spacing is greater than The spacing of CB-FG is typical of Bernal graphite, indicating an expanded and turbostratic structure of FG. The (002) peak was found to be asymmetric with a small angle tail, which further indicates the turbostratic nature of FG. [Li 2007]. The flash process is fast enough to prevent AB order stratification. The surface area of ​​CB-FG is ~295m 2 ·g -1 , and the pore size is <9 nm as measured by Brunauer-Emmett-Teller (BET) analysis. Figures 3A-3D . Figures 3A-3D The BET surface area analysis of CB-FG is shown, where Figure 3A is an isotherm, Figure 3B is the BET surface area fit, and Figure 3C-3D is the absorption and desorption pore size distribution. Anthracite and calcined petroleum coke also perform well for conversion to FG ( Figure 1Eand Table I). The yield of the FJH process from high carbon sources such as carbon black, calcined coke or anthracite is as high as 80-90%, and the electrical energy required for their conversion is ∼7.2 kJ·g -1 .

[0281] FG derived from coffee (C-FG) produces larger graphene sheets compared to other FGs. Prior to the FJH process, a mixture of used coffee grounds and 5 wt% CB was prepared because coffee alone is non-conductive. Instead of using CB, 2-5 wt% of FG from a previous run can act as a conductive additive to the coffee grounds. By XRD, in addition to the main (002) peak at 26.0°, a sharp (001) peak at 2θ = 42.5° was observed, which is associated with the in-plane structure. Using HR-TEM, we observed that ( Figure 1E ) Folded graphene sheets with a size of 0.5-1 μm, which is similar to the size of graphene sheets obtained by graphite exfoliation. 3,12,13 [Hernandez2008; Stankovich 2007; Cai 2012].

[0282] Other carbon sources that are abundant, renewable, or waste sources can be used to convert to FG, including charcoal, biochar, humic acid, keratin (human hair), lignin, sucrose, starch, pine bark, olive oil soot, cabbage, coconut, pistachio shells, potato peels, or mixed plastics including polyethylene terephthalate (PET or PETE), high-density or low-density polyethylene (HDPE, LDPE), polyvinyl chloride (PVC), polypropylene (PP), polyacrylonitrile (PAN), or mixed plastics. See Figure 4 , which shows representative Raman spectra of FG obtained from other carbon sources.

[0283] Figure 4 The precursor sources are shown in Table II (and pine bark, olive oil soot, cabbage, keratin from human hair, coconut, pistachio shells, potato peels, PETE, HDPE, PVC, LDPE, PP, and PS are collectively referred to as waste products). Biochar is conductive enough; it does not need additives. All other non-plastic samples have had 5-10wt% CB added to increase their conductivity. It is also shown that 2-5wt% of FG from a previous run can be used to replace CB as a conductive additive. #7 Plastic "Other" is polyacrylonitrile (PAN). The mixed plastics are made of the following wt% of polymers: HDPE 40%, PETE 40%, PP 10%, PVC 10%. All plastic samples have had 5wt% CB added to increase their conductivity.

[0284] The FJH process could provide an easy path to convert these waste products found worldwide into FG, a potential high-value additive to building composites. [Parfitt 2010; Gustavsson 2011; Jambeck 2015]. This would immobilize these carbon sources and prevent their conversion to carbon dioxide, methane, or harmful micro- or nano-plastic waste. The ability to convert mixed plastics into a single FG product is particularly attractive for waste recycling.

[0285] Table II

[0286] Bio-coke Neroval LLC, from mixed Tennessee hardwoods, commercially prepared at 1100°C charcoal Sigma CAS: 7440-44-0 Humic acid Sigma CAS: 1415-93-6 Lignin Sigma CAS: 8068-05-1 sucrose Sigma CAS: 57-50-1 starch Argo Gluten Free PAN Sigma CAS: 25014-41-9

[0287] Graphene I 2D / G The temperature and duration of the flash are controlled by optimizing the sample compression between the electrodes (which affects the sample conductivity), the capacitor voltage, and the switching duration. Figure 5A-5G . Figure 5A-5G The FJH critical parameters are shown. Figure 5A is the Raman spectrum of CB-FG with increasing flash voltage. Figure 5B CB-FG I at different flash voltages 2D / G and I D / G Summary of ratios (where graphs 501-502 are for 2D / G and D / G, respectively). The bars represent the standard deviation over 10 points. Figure 5C 503-504 are time-temperature diagrams of CB-FG reacted under different conditions (wherein the diagrams 503-504 are for 3100K and 2850K, respectively). The temperature is regulated by the flash voltage. Figure 5D 505-508 are time-temperature diagrams of CB-FG reacted at different flash durations (Figures 505-508 are for 10 ms, 150 ms #1, 150 ms #2, and 50 ms, respectively). The flash duration is regulated by sample compression between electrodes that affects sample conductivity. The numbers in the figure represent the cooling rate in each method (which is 30000 K s -1 , 7000K s -1 , 50000K s -1 and 20000K s -1 , corresponding to Figures 505-508 respectively). Figure 5E are the Raman spectra of CB-FG with different compression ratios. Higher compression gives the sample lower resistance. Fig. 5F is Figure 5C Raman spectra of CB-FG at different flash temperatures. Figure 5G is Figure 5D Raman spectra of CB-FG at different flash durations. 150ms#1 and #2 flashes have similar durations but different cooling rates, such as Figure 5D shown. Figure 5A and 5E All Raman spectra in -5G were acquired at low magnification (5×) in order to produce an average spectrum of the sample.

[0288] Increasing the voltage increases the temperature of the process.The temperature was estimated by fitting the blackbody radiation spectrum in the 600-1100 nm emission. Figures 6A-6C . Fig. 6A is a schematic diagram of the temperature measurement device. Figure 6B The blackbody radiation from the sample is collected by an optical fiber through a custom grating black box. The spectrum of the radiation fills a 16-pixel photodiode array (Hamamatsu S4111-16R) at 600nm-1100nm. The optical path is shown in Figure 6B The reverse bias voltage (9 V) from the photodiode array was collected by a National Instrument multifunction I / O device PCIe-6320. Figure 6C is a graph showing the blackbody radiation fit. The temperature at each point from the temperature versus time graph is determined by fitting the blackbody radiation from the spectrum of 0.6-1.1 μm emission. Insets 631, 641, and 651 are the spectrum fits for 3000K, 3500K, and 2500K, with graphs 632, 642, and 652 for real time data, and graphs 633, 643, and 653 are the fitted curves.

[0289] CB-FG quality is determined using Raman spectroscopy at low magnification by varying time and temperature. At less than 90 V and less than 3000 K, FG has a high D peak, which indicates a defective structure. See Figures 5A-5C and Fig. 5F By increasing the voltage output, CB-FG is formed at 3100K, and it has low defects and almost no D band in the Raman spectrum. Therefore, 3000K is suitable for the nanostructured ... 2D / G The critical temperature reached for higher quality graphene is of great value.

[0290] By increasing the compression of the sample between the two electrodes, the conductivity of the carbon source is increased, thereby reducing the discharge time. Figure 5D-5E and Figure 5G At the same 3200K, a short flash duration of 10ms produces a higher 2D band, while a flash of 50-150ms produces a lower 2D band product. Figure 5G This indicates that given more time, the graphene flakes stack, orient and form more layers, which reduces the 2D banding of the formed FG. Slowing the cooling rate increases the flash duration and reduces the 2D banding. [Yao 2018]. Therefore, in order to have a high I 2D / G, a thin quartz tube can be used to accelerate the radiative cooling rate. Interestingly, although the internal temperature exceeds 3000K, the outer wall of the quartz tube is only warm to the touch (less than 60°C) after the flash process. Most of the heat exists as black body radiation.

[0291] Figures 7A-7F Here are X-ray photoelectron spectra (XPS) of calcined petroleum coke, pretreated coffee and carbon black before and after the FJH process. A significant reduction in pollutants is seen using FG from carbon black, i.e. a significant reduction in the presence of non-carbon elements in the FG. Carbon has a high sublimation temperature of about 3900 K. Other elements such as aluminum or silicon vaporize at less than 3000 K.

[0292] Thermogravimetric analysis (TGA) in air showed that the FG products were more oxidatively stable than the materials from which they were derived ( Figures 8A-8D ) and they are more stable than reduced graphene oxide (RGO) made by the Hummer method. [Advincula 2018]. Fig. 8A In the figure, TGA curves 801-802 are for CB-FG and crude CB, respectively. Figure 8B In the figure, TGA curves 803-804 are for anthracite-FG and coarse anthracite-FG, respectively. Figure 8C In FIG. 8 , TGA curves 805-806 are for CC-FG and crude calcined coke, respectively. Fig.8D In FIG. 8 , TGA curves 807-808 are for coffee-FG and pretreated coffee, respectively.

[0293] With carbon black, anthracite and coffee, there is a significant drop between the final weight of the precursor material and the FG obtained therefrom. XPS of the TGA residues showed that the TGA-residue from anthracite-FG contained C (15%), O (62%), Si (11%) and Al (12.6%); and the residue from coffee-FG contained C (65%), O (25%), S (2.9%) and P (2%). In some cases, silicon oxide residues from quartz tubes that were excessively worn after multiple uses were detected. As Fig. 8E As shown, the TGA residue from coffee-FG was analyzed by Raman spectroscopy, which showed that it was mainly graphene. It is believed that the removal of hydrogen, nitrogen and oxygen during the FJH process may lead to the formation of large and thin graphene sheets in FG obtained from coffee, because it prevents the stacking of graphene layers, thereby allowing further growth. [Harris 2017; Lin 2014; Luong 2018].

[0294] Mechanism of FG growth

[0295] To evaluate the mechanism of rapid flash graphene growth, large-scale simulations were performed using the AIREBO [Stuart 2000; Brenner 2002] interatomic potential as implemented in the LAMMPS package [Plimpton 1995]. Figure 2A -FJH system shown in 2D (discussed above). In a quartz tube, two loosely fitting electrodes use two copper wool plugs or graphite spacers to compress the carbon source to contact the carbon source to degas the volatile materials. The compression force can be controlled by a modified small vise to minimize the sample resistance to 1-1000Ω, and this is an important factor for obtaining a good flash reaction (0.004-4S·cm -1 ). In order to control the discharge time, a mechanical relay with a programmable delay time of milliseconds was used. The entire sample reaction chamber was placed inside a low pressure container (plastic vacuum dryer) for safety and to promote degassing. (However, the FJH method works equally well at 1 atmosphere). The capacitor bank consists of 20 capacitors with a total capacitance of 0.22F. Each capacitor has its own available switch. The capacitor bank is charged by a DC power supply capable of reaching 400V. Using a large quartz tube with a diameter of 15mm, 1 gram / batch of FG synthesis was achieved using the FJH method.

[0296] All switches are circuit breakers, which match the voltage and current ratings. The maximum charge and discharge voltages used are about 400V, and the maximum currents are 0.7A and 0.1A, respectively. The pulse discharge voltage to the sample is about 400V, and the current can reach up to 1000A in less than 100ms. A 24mH inductor is used to avoid current spikes when using mechanical relays. Without an inductor, the mechanical relay may tend to have high current arcs during intermittent closure of the circuit. In order to protect the inductor from spike voltages when the current is cut off, a diode and a low-ohm resistor with an appropriate rating are connected in parallel with the inductor. In addition, in order to protect the capacitor from the opposite polarity in the case of oscillation delay (which may occur in rapid discharge), a suitable diode is placed in parallel with the capacitor bank.

[0297] Some of the obtained structures are shown in Figures 9A-9D In. Figures 9A-9D In the figure, the sample structures of carbon materials with various densities after annealing at 3000K: Fig. 9A is 0.8 g cm -3 , sponge-like structure; Fig. 9B is 1.1 g cm -3 ; Fig. 9C is 1.5 g cm -3 , high degree of graphitization. Fig.9D Display at 3600K for a long time (5×10 -9s) After annealing, it has 0.8g.cm -3 The density and large macropores of carbon black with polygonal edges are evident.

[0298] Low-density materials develop a sponge-like structure during annealing ( Fig. 9A ), while increasing density leads to high graphitization levels ( Fig. 9C ). A high level of graphitization is present in low-density CB samples, where a significantly increased local density is combined with high macroporosity ( Fig.9D ). Figure 9G shows 1.5 g·cm after annealing at 5000 K -3 Structure, initial structure and use Fig. 9C The same.

[0299] In addition, the annealing process is simulated by sp 2 / sp 3 quantified by ratio. Figures 9E-9F The changes in the structural composition of materials with different densities and temperatures during annealing are shown. It is found that the graphene formation process is significantly weakened at lower temperatures (less than 2000K), but is significantly accelerated by higher temperatures (5000K). Figure 9G shows 1.5 g·cm after annealing at 5000 K -3 Structure, initial structure and use Fig. 9C In the case of carbon black, continuous defect healing during FJH leads to a gradual transformation of the initially roughly spherical centroid particle to a polyhedral shape ( Fig.9D ), which can be seen in TEM images of experimental materials as fringes at clearly defined angles (see Figure 1B and 1E ), which further confirms the low-defect nature of the produced material.

[0300] Graphene

[0301] 2D-Material

[0302] Although graphene is often described as a single carbon sheet, it generally occurs as a single isolated sheet only under specialized laboratory conditions. In any substantial production method disclosed and taught herein, graphene may be present in aggregate form. The field of the invention has defined graphene as a 2-dimensional (D) material, in contrast to carbon nanotubes, which are 1-D materials, and graphite, which is a 3-D material. [Novoselov 2004; Allen 2009; Partoens 2006; Malard 2009]. When the sp in these aggregates is 2When the carbon sheet retains the electronic structure of a 2-D rather than a 3-D material, a descriptive adjective is used as a prefix, such as bilayer graphene, few-layer graphene, N-layer graphene; and if adjacent sheets are randomly oriented rather than AB stacked, several different adjectives with the same meaning are used, such as: misoriented [Partoens 2006], twisted [Yan 2013], rotated [Kim 2012], rotationally faulted [Kato 2019; Niilisk 2016], weakly coupled [Kiselov 2014], and turbostratic [Garlow 2016]. Despite the various terms, it is recognized in the art that in all cases, when randomly stacked, the individual layers retain their 2-D properties. Therefore, the use of the term "graphene" in this article for such stacking is supported in the scientific literature by leading scientists in the field, even when there are many layers.

[0303] Fig. 10A is a diagram of a graphene lattice 1001-1002 in an AB stacking order. Fig. 10B are illustrations of non-AB stacked or turbostratic graphene lattices 1001-1002. These illustrations are reproduced from Hao 1990.

[0304] Raman spectroscopy provides direct monitoring of the electronic structure and is also completely unambiguous in identifying the 2-D nature of these aggregates. Raman spectroscopy is the “gold standard” for graphene diagnostics as it emerges in experimental studies. [Malard 2009; Kim 2012; Kato 2019; Niilisk 2016; Ferrari 2006; Ferrari 2007; Kudin 2008; Ni 2009; Ferrari 2013]. That’s because it is a direct probe of graphene’s electronic band structure, which in turn plays a central role in the unique properties of this 2-D material.

[0305] It is not the physical size or the number of atomic layers, but the properties, especially the electronic properties, that make up 2-D materials. Graphene is characterized by a 2-D gas of Dirac fermions. [Novoselov 2005]. 2-D materials are materials that are highly anisotropic in terms of electron mobility, just as carbon nanotubes are 1-D materials due to their high mobility in one direction. For graphene, the mobility is ballistic in the xy plane, but when stacked, the c-axis mobility is significantly smaller. And turbostratic graphene has the greatest anisotropy of all, and even for multilayers, remains completely 2D, with ballistic mobility in two dimensions, and orders of magnitude lower conductivity in the third dimension.

[0306] Experimental measurements by Kim et al. confirmed that when graphene sheets are stacked in a twisted fashion, a large anisotropy between electrons that travel ballistically in the plane and those that attempt to cross between the layers is preserved [Kim 2012]. They reported that HOPG is about 10 -3 Ohm-meter resistivity, which is ~5 orders of magnitude higher than copper, and the interlayer resistivity is also 4 orders of magnitude. While the in-plane transport of turbostratic graphene remains ballistic for electrons.

[0307] It has also been reported previously that for AB (also called aligned or Bernal) stacked graphene, the 2-D properties of single-layer graphene (SLG) or few-layer graphene (FLG) gradually transform into 3-D materials, and as the Raman spectrum evolves to that of HOPG around 10 layers. [Partoens 2006; Novoselov 2005]. However, this rule of thumb does not apply to turbostratic graphene. Because the individual layers are weakly coupled, they retain the 2-D properties independently of the number of stacked layers. [Kim 2012; Niilisk 2016]. The 2D peak retains its Lorentzian line shape, and no additional states are introduced into the Dirac cone at the K point. Therefore, the Raman scattering for the 2D peak remains a single peak, which is doubly resonantly enhanced, which causes its strong enhancement. And it remains a zero-gap semiconductor. In contrast, when the two layers are AB stacked, then the strong coupling produces additional states with a parabolic shape around the K point, which allows for a larger transition. The 2D peak becomes the sum of four Lorentzians, two strong and two weak, and it is significantly broadened, losing its Lorentzian line shape. Studies have reported rotationally misoriented graphene, some produced by innovative methods of folding a single sheet, which ensures the misalignment. As a result of the poor overlap of the 2p atomic orbitals, the two sheets retain their SLG properties. [Kim 2012; Niilisk 2016; Garlow 2016].

[0308] The presence or absence of certain relatively weak Raman combination bands is a positive indicator of the occurrence of turbostratic graphene:

[0309] ●At 1650cm -1 Up to 2300cm -1 The combined Raman modes of the as-grown graphene in the frequency range, as well as the characteristic Raman 2D modes, are used as the signature of turbostratic graphene.

[0310] • Combination of in-plane transverse acoustic (iTA) and longitudinal optical (LO), iTA and longitudinal acoustic (LA) and LO+LA modes. The iTALO mode is called TS1, and the iTOLA / LOLA mode is called TS2.

[0311] TS1 and TS2 can be used as positive indicators. The names TS1 and TS2 are used in the text to indicate that these two features are Raman active only for SLG and turbostratic graphene. TS1 is a single Lorentzian with a peak at 1880 cm -1 TS2 consists of two close spatial Lorentzians at 2030 cm -1 It is important to remember that these lines appear dispersed, like many Raman features in graphene. Attention must always be paid to the excitation wavelength, and when comparing peak frequencies, a dispersion correction must be applied. In addition, the "M" band occurs at about 1750 cm -1 , but this combined band of turbostratic graphene becomes vanished. Therefore the presence of M band is a negative indication for turbostratic graphene and a positive indication for AB stacked graphene as well as HOPG.

[0312] Turbostratic Graphene

[0313] Turbostratic graphene, even with many layers, is a true 2-D material in which electrons move in two dimensions in a completely free manner like a massless Fermi gas, but cannot actually move perpendicular to the two dimensions. The hardest thing would be to find any other material that is as pure 2D as multilayer turbostratic graphene. The turbostratic properties of FG make it significantly easier to exfoliate in composite materials and solvents, and give it different electronic, optical and structural properties as described herein below, and are therefore a key quality of this bulk synthesized turbostratic FG.

[0314] The D peak of turbostratic graphite is much larger than both the G peak and the 2D peak, which is in stark contrast to our turbostratic graphene samples, where the D peak is significantly smaller than the G peak, which in turn is smaller than the 2D peak. [Kumar 2013]. Raman spectroscopy is a probe of the vibrational motion of atomic structure, so the huge D peak is evidence that the individual graphene lattices are significantly disrupted in turbostratic graphite. It is extremely disordered at the nanoscale. And that is why researchers lament that the slow progress of the research field into the very promising field of turbostratic graphene has been attributed to the difficulty of obtaining the material. [Kato 2019; Garlow 2016] That is, turbostratic graphene can only be produced in trace amounts by CVD or epitaxial growth. See also Tour's '821 patent application, in which turbostratic laser-induced graphene was produced, which was not a bulk synthesis method in that the laser was only able to produce a 20 micron thick surface of it, and less than 1g could be produced after a full day of lasering.

[0315] And even growth under such careful conditions does not ensure that the material will be turbostratic. One group that was able to try growing 10 layers of graphene on nickel foil using CVD obtained varying results, sometimes AB stacking, sometimes turbostratic and sometimes a mixture of the two [Niilisk 2016].

[0316] Raman spectroscopy confirms that the FG method of the present invention can produce a large amount of turbostratic graphene. Fig.11 The turbostratic peaks in the Raman spectrum of flash graphene from carbon black are shown. Fig.11 middle, I G / TS1 is ~30 and the Lorentzian fits are shown as overlaid smooth lines. The R squared is 0.994 for TS1 and 0.99 for TS2. These excellent fits indicate the high quality of the material and the unmistakable presence of the Raman lines of turbostratic graphene. Fig.11 It also shows the absence of the M peak, another indication of turbostratic graphene.

[0317] Figures 12A-12B The 2D peaks in the Raman spectrum of flash graphene from carbon black are shown. Fig. 12A shows the best point in CB-FG, and Fig. 12B Representative points for CB-FG are shown. Both peaks exhibit essentially perfect Lorentzian line shapes. Figures 12A-12B The points in are the theoretical line shapes. 2 It is 0.999 for both peaks. This is an indication of a perfectly conical Dirac cone at the K point.

[0318] A narrow single Lorentzian 2D peak can occur only for SLG or turbostratic graphene, whereby the adjacent layers are decoupled and no additional electronic states are generated. This in turn means that FG retains perfect 2-dimensionality even in the presence of many graphene layers stacked on top of each other. Fig. 12A , the Lorentz full wave at half maximum (FWHM) has actually become narrower than that of perfect SLG. This narrowing is a unique feature of stacked rotationally misaligned graphene and occurs only for turbostratic graphene.

[0319] Table III is a comparison of the 2D, TS1, and TS2 peaks of FG produced by the inventive FG method disclosed herein with turbostratic graphene produced in previous studies [Niilisk 2016; Garlow 2016]. The peak positions from the previous studies using a 514 nm excitation laser were corrected to match the 532 nm excitation laser in this study.

[0320] Table III

[0321]

[0322] Comparing the FG spectra with data from two different references [Niilisk 2016; Garlow 2016], the positions and FWHMs of the two TS (turbostratic) peaks are essentially the same in both cases. The positions of the 2D peaks are also identical, and the FG wider Lorentzian matches the FWHM from Garlow 2016. Comparing with Niilisk 2016 (which has about 10 layers of turbostratic graphene), there is also the same match in both frequency and width for the TS1 and TS2 peaks. The 2D also matches the frequency, although the peak is somewhat broad for Niilisk. And for both references [Niilisk 2016; Garlow 2016], there is no M peak, which is characteristic of both AB stacked graphene and highly ordered pyrolytic graphite (HOPG). And there is no M peak in the FG spectra either. Thus, there are several precise and redundant correlations between the FG turbostratic Raman data and two references with Raman spectra obtained from demonstrated turbostratic graphene [Niilisk 2016; Garlow 2016]. Additionally, the narrowing of the 2D Lorentzian FWHM further supports turbostratic stacking as a 2D material.

[0323] Furthermore, the method of detonating carbonaceous materials disclosed and taught in the Sorensen '857 patent (for high yield production of graphene) neither mentions nor reveals the formation of turbostratic graphene. Indeed, the Sorensen '857 patent does not show TEM of few-layer graphene; does not show SAED of misaligned few-layer graphene; and does not show TS1 and TS2 peaks of turbostratic graphene. Rather, the Sorensen '857 patent does not show TEM of few-layer graphene; does not show SAED of misaligned few-layer graphene; and does not show TS1 and TS2 peaks of turbostratic graphene. Fig.14 The 2D band in the Raman spectrum is significantly broader than that of monolayer graphene and increases to 43 cm -1 Up to 63cm -1 This is a property of AB stacked crystalline graphene or turbostratic graphene, which exhibits a similar or narrower FWHM bandwidth than monolayer graphene and will be significantly less than 43 cm -1 All of this supports that Sorensen'857 patent does not produce turbostratic graphene, while the FG method of the present invention produces low-defect turbostratic graphene. We use low-defect to mean that the individual graphene sheets are mainly sp 2 and therefore those individual sheets are stacked in a predominantly turbostratic manner relative to each other, with AB stacking rarely observed in the sample.

[0324] As mentioned above, other researchers have made very few samples of turbostratic graphene by growing individual graphene sheets via CVD or via graphite exfoliation and placing one graphene sheet on top of another in a misoriented (turbostratic) manner. Or by taking a single sheet of CVD-grown graphene or graphite exfoliated graphene and folding it over itself in a misoriented (turbostratic) manner. But there has been no bulk synthesis of misoriented or turbostratic graphene, where the majority of the graphene in the bulk sample is turbostratic.

[0325] Continuous / Automated Synthesis System

[0326] Scaling up the FJH process can be done by increasing the size of the quartz tube. Using 4 mm, 8 mm, and 15 mm diameter quartz tubes, 30 mg, 120 mg, and 1 g of FG were synthesized per batch. Fig.13A The amount of CB-FG from three tube sizes (where tubes 1301-1303 have diameters of 4 mm, 8 mm, and 15 mm, respectively) and a flat tube 1304 of size 3×6 mm is shown. Two separate syntheses were performed for each; one synthesis remained in the tube (tubes 1301-1304), and the other synthesis was transferred to a plastic tray (trays 1305-1308, respectively). The amount of each batch synthesis for tubes 1301-1304 was 0.003 g, 0.1 g, 1 g, and 0.1 g, respectively. The shorter flash from the smaller tubes produced a CB-FG with a higher I 2D / G To increase batch size while maintaining FG quality, flat tubes help allow for faster cooling rates.

[0327] For industrial production, the method can be automated for continuous FG synthesis. Fig.14 It is an automated implementation of the FG method. Fig.14 It is a continuous belt FG process with a belt 1408 and gears (first gear 1401 and second gear 1402) for high throughput in a FJH system. The rotational movement of the gears 1401-1402 is synchronized with the movement of the belt 1408, and there are separate gears for preheating and flashing. That is, the first gear 1401 has an electrode 1413 for compression and preheating, and the second gear 1402 has an electrode 1414 for FJH pulses. It is believed that the rate can be at least 60pps.

[0328] The belt 1408 has a quartz (or ceramic) tube 1405 which can be unplugged and replaced. Fig.14As shown, a quartz tube 1405 may be mounted on a spring with a weak friction fit away from the gears 1401-1402 and protrude beyond the cylindrical electrode. This forms a cup with the electrode 1412 at the bottom of the quartz tube 1405, and a powder feed 1404 of the precursor is metered into the quartz cup 1405. The metered feed may be an auger, meshing gear or piston feed, and is typically straight feed, so there is a variety of powder feeds available.

[0329] The belt 1408 can be moved by rollers 1407, which can be metal. When the electrode 1413 in the first gear 1401 engages, it protrudes into the top of the quartz cup 1405, compressing the precursor powder. When the electrode 1414 in the second gear 1402 engages, an electric pulse converts the sample into FG. The system includes a series of gas injectors 1403, which can blow cold air onto the various electrodes (electrodes 1412-1414). The air blown from the gas injectors 1403 can also be used to clean the quartz cup 1405 and remove particles. (Water spraying is also optional). In order to remove FG from the quartz cup, the quartz cup can be lowered (it passes through Fig.14 ), and using the gas flow from the nozzle 1140, the FG is removed from the quartz cup 1409 and collected in the collection box 1411.

[0330] Since hot carbon atoms are strongly reducing and corrosive, the quartz cup 1405 may be damaged. A wheel or robotic arm 1406 may unplug, for example, every tenth quartz cup for cleaning or replacement, and the newly provided clean cup is further rotated along the belt 1128. With such a simple replacement scheme, low expansion borosilicate (Pyrex) may be suitable (Pyrex has been tested and performs well), and costs much less than a quartz tube / cup. Since damage tends to be cumulative, frequent cleaning of the quartz cup may allow many cycles of reuse.

[0331] Three-phase AC power system

[0332] Scaling up flash graphene can include high power pulses. Commercial and industrial power in the United States is three phase, 60Hz, and each sine wave is shifted 120 degrees. This has the advantage of providing uniform power when all three phases are used. For high power systems, it is preferable to avoid having an unbalanced load, thereby using one or two of the three phases and not using the others.

[0333] Single phase power can be used, and has a 60 Hz sine wave, with each half cycle being 1 / 120 second in duration. The power passes through zero 120 times per second, and the heating is not uniform in time. Adding a half cycle also adds an increment of 8.33 ms, which is a larger change in pulse energy compared to three phase power. If the single phase is obtained from a single conductor and a common terminal, this is 120 volts or 277 volts. If two of the three circuits are used, it is still a single sine wave, and the RMS voltage increases by the square root of 3 = 1.732. This may not be necessarily desirable for larger systems, due to the unbalanced load on the input power supply.

[0334] Fig.15 1501-1503 are graphical representations of three sine waves of three-phase power that may be used with embodiments of the present invention (i.e., curves 1501-1503 represent phase 1, phase 2, and phase 3 (at 60 Hz), respectively, and curve 1504 represents the common terminal (or neutral terminal)). Three-phase power uses three circuits or wires. Phases 1-3 are shifted 120° and are spaced 1 / 180 seconds apart. For laboratory power, it may be 120 volts (RMS) to ground and 208 volts (RMS) between the two phases (powered wires). Unlike single phase, which passes through zero 120 times per second, three-phase power is uniform.

[0335] Three-phase power is available at multiple voltages. For higher power industrial systems, 480 volts (RMS) between phases may be used, which is also 277 volts (RMS) relative to the common terminal (or neutral terminal). Likewise, 575 volts (RMS) is also used industrially. Distribution transmission lines typically use 5kV or 12kV (RMS) between phases.

[0336] To produce flash graphene, a pulse duration is selected which is then subjected to full-wave rectification to provide DC power to the sample.

[0337] Fig.16 1603 is a diagram showing a three-phase scaled-up for FG, which is a device for controlling pulse duration, followed by rectification for use in the FG method to make FG 1603. The device has three zero-crossing relays (relays 1601a-1601c), which do not require (or require) precise timing. Relays 1601a-1601c have phase inputs 1605a-1605c, respectively, which are three-phase inputs that can have 208 volts between phases. A trigger generator 1602 is required. Diode 1604 is used for full rectification. Rectification to DC requires having two leads (positive lead 1608 and negative lead 1609).

[0338] Zero-crossing relays 1601a-1601c are used to connect each phase. These solid-state relays 1601a-1601c are designed to connect when the phase voltage passes through zero, so that the current is about zero when the relay is closed or opened. The relay does not switch when there is a high current flow. The pulse from the trigger generator 1602 can precede the zero crossing. Relays 1601a-1601c can be called common terminals or ground terminals when they are connected or disconnected. The trigger generator 1602 disconnects to stop the flash graphene pulse, and disconnects relays 1601a-1601c when the voltage passes through zero. Six power diodes 1604 convert three AC sine waves into continuous DC currents for flash graphene 1603.

[0339] Fig.17 1706 is a diagram of a flash graphene pulse 1706 formed from three phase power (pulses for phases 1-3 are shown in waveform curves 1701-1703). Three phase power uses three conductors, with each sine wave (represented by curves 1701-1703) shifted by 120°. The average power is uniform. Each delay waits after the trigger signal for the next zero crossing is turned on or off as the case may be. In this way, a single on / off command is required.

[0340] For each waveform curve 1701-1703, the dotted line represents the available voltage. When each relay is turned on (due to the turn-on command 1704), the solid lines of the curves 1701-1703 represent the power flow. When the AC sine wave passes through zero volts relative to the common terminal or neutral terminal, each phase is turned on respectively. Each is turned off respectively in a similar manner, which is due to the disconnect command 1705 (and similarly, when the AC sine wave passes through zero volts relative to the common terminal or neutral terminal, the phase is disconnected).

[0341] As shown in Figure 1706, the rise time follows the shape of a sine wave, so it takes milliseconds to switch on, which provides a smooth increase and a smooth decrease when the relay is off. When all three phases are on, the power output is constant. This is then rectified to provide two wires connected to the flash graphene sample.

[0342] The total transmitted energy is regulated via the number of cycles through the relay. Since the sine waves cancel out over 1 / 360 seconds (2.78 ms), this corresponds to an incremental change in the total pulse energy.

[0343] Fig.18 is a diagram showing a three-phase scaled-up FG, which is a device used to control the pulse duration and then rectify the FG method used to make FG 1603, which directly controls all three zero-crossing relays. This device is similar to Fig.16 The device includes a computer 1801 for accurate phase detection.

[0344] exist Fig.18 In the alternative embodiment shown in , using computer 1801, trigger generator 1602 can be synchronized with the line frequency and can provide a switch-on command just as the sine wave passes through zero. Since all three sine waves are synchronized with respect to each other, two delay circuits can be used to provide the trigger signals for the other two relays. The same system can be used to switch off the relays.

[0345] For three-phase AC power for flash graphene, the generator has the advantage of decoupling the high current required for large samples from the AC mains. The generator rotor can have a large amount of rotational inertia. It can convert the stored mechanical energy into electrical energy very quickly. The generator can be accelerated with a significantly smaller motor, which will spread the power consumption over a few seconds to a few minutes, which is a much smaller strain on the power transmission line. The output voltage can be changed by reducing the RPM, or reducing the voltage on the excitation coil, depending on the design of the generator. A flywheel can be added to provide a longer duration pulse. However, for a short pulse of 100ms, the inertia of the armature may be sufficient. Large commercial generators provide 3-phase AC power of 208 or 480 volts. Large industrial generators provide 5kV and 13kV. The generator may be able to withstand a transient current overload of 5-10 times its rated continuous current to provide a more powerful pulse.

[0346] In some embodiments, the motor can be used as a generator. If it is driven by an external mechanical source, the three-phase motor can act as a generator and push current back into the AC power line. In order to use the motor as a standalone generator, it may be necessary to provide a weak current in the field coil to energize the magnetic field. For example, three series resistors can be used to energize the coil. Three-phase motors of all sizes are readily available and known in the art.

[0347] In some embodiments, a DC generator may be used, but a DC generator may be more limited in current output due to the carbon brushes of the commutator connected to the coils on the armature, and may also be unable to handle high current surges. Additionally, the current will need to be switched with an IGBT or similar control module.

[0348] In some embodiments, a single phase generator may be used.

[0349] In some embodiments, a 400 Hz generator may be used. Aircraft, some ships, and the military use 400 Hz generators, which are physically significantly smaller for the same amount of power output. However, a 400 Hz generator will have less rotational inertia and may increase the need for a flywheel.

[0350] Uses of FG

[0351] While laser induction methods produce defective laser-induced graphene [Lin 2014], CVD is able to synthesize large-scale single-crystalline graphene [Yan 2012]. FJH will bridge the time-formation gap between the following two graphene synthesis schemes: laser induction and chemical vapor deposition (CVD).

[0352] Fig.19 is a graph showing the time-temperature relationship of various graphene synthesis methods. Fig.19 As shown, laser-induced methods always occur within milliseconds due to the use of photothermal conversion, which is expected to produce defective laser-induced materials. CVD and hydrothermal methods allow slow atomic rearrangement and gradual growth of thermodynamically stable materials. But in flash heating methods, a wider temperature range can be achieved within seconds. This limited duration makes it possible to synthesize metastable forms of materials that are very difficult to synthesize directly by CVD or hydrothermal methods, and here there are no additional reagents.

[0353] Advantages and improvements include that for the first time, high quality graphene can be synthesized on a large scale in a very low cost solvent-free and scalable process. In addition, the method also shows the synthesis of graphene from a carbon source without the use of a catalyst. Still further, by studying the FJH method, the time-temperature phase transition of graphene from defective graphene to ordered graphene can be mapped.

[0354] In some embodiments, non-uniform heating may cause different graphene qualities in a batch. This can be solved and overcome by using large but thin samples. Also, the graphene quality can be improved by multiple pulses such as 3-5 pulses in succession.

[0355] The invention can be commercialized by a pellet feed process that flash heats low cost starting material into high quality graphene and drives the material out through an electrode piston and then re-feeds to perform the process again. Significantly larger capacitor banks can be used to increase the speed of the process because their charging time can be reduced. Heteroatoms such as nitrogen in the form of melamine or melamine formaldehyde resin can be added to provide nitrogen doped graphene, or phosphine to provide phosphorus doped graphene. Metal salts can be added to provide metal nanoparticle doped graphene or single metal atom doped graphene. The two methods such as nitrogen doping and metal atom doping often work together to provide more stable metal doped or metal atom doped graphene. [Han 2018; Ye 2018; J. Zhang 2018; J. Zhang 2017; C. Zhang 2017].

[0356] Variations of the invention include: improving product uniformity; using high surface area carbon materials and KOH activation; using other carbon sources; and increasing yields by multiple flash distillations. A "carbon source" is a source containing at least 10% carbon content by weight. Preferably, the carbon source has at least 80% carbon by weight. In addition, rather than using DC (direct current) systems for flash distillation, AC (alternating current) systems have also been made and they work just as well.

[0357] Dispersion

[0358] FG is 1-10g.L -1 The concentration of FG was dispersed in a water / Pluronic (F-127) solution (1%). This dispersion is easily accomplished due to the turbostratic nature of FG, where the layers are not strongly coupled to each other by van der Waals interactions as seen in AB stacked graphene (especially AB stacked graphene or graphite nanosheets obtained from graphite exfoliation methods). The mixture was sonicated in an ultrasonic bath for 40 min to obtain a dark dispersion. The dispersion was centrifuged at 1500 rpm for 30 min using a Beckman Coulter Allegra X-12 centrifuge to remove aggregates. The supernatant was analyzed via UV-VIS (Shimadzu). The dispersion was diluted 500 times and the absorbance at 660 nm was recorded. The α 660 =6600L·g -1 ·m -1 The extinction coefficient is used to calculate the concentration of graphene in the solution. Fig. 13B As shown, FG was found to be dispersible in water / surfactant (Pluronic F-127) to produce a concentration of 4 g·L -1 A highly concentrated dispersion. Fig.13E After centrifugation, 4 g·L -1 of( Fig. 13B CB-FG (vial 1309) and 10 g L -1 Photograph of a commercial sample (vial 1310). Commercial graphene will not disperse.

[0359] like Fig. 13C As shown, due to its turbostratic nature, FG exhibits a high degree of dispersibility in a wide range of organic solvents (NMP 1311, xylene 1312, DCB 1313, and DMF 1314). The concentration of FG dispersions is 4 times (4×) that of most concentrated graphene dispersions produced by conventional graphite liquid phase exfoliation, and the concentration is more than 10 times higher than many reported values ​​for graphene nanosheets.

[0360] FG Composites

[0361] The FG composites showed that small FG loading significantly improved the physical properties of the composites, again indicating that its turbostratic nature allows for significantly easier exfoliation than seen in other forms of stacked graphene. FG was dispersed in 1% water-Pluronic (F-127) solution at various concentrations. The dispersion was stirred at 5000 rpm for 15 min using a shear mixer (Silverson L5MA). The graphene suspension in water was mixed with Portland cement at a water to cement ratio of 0.40. The slurry was cast into 5×5×5 cm 3 The PTFE cube mold (for compressive strength) and 2.5 cm × 3.8 cm cylindrical mold (for tensile strength) were placed in PTFE cube molds (for compressive strength) and 2.5 cm × 3.8 cm cylindrical molds (for tensile strength). All cubes and cylinders were removed from the molds after 24 hours and placed in water to cure for another 24 hours. The compressive and tensile mechanical strengths were measured after 7 days. Fig.13D As shown, the CB-FG / cement composite with 0.1% FG has about 35% higher compressive strength (Figure 1315) and 19% higher tensile strength (Figure 1316) than the control sample without FG. These improved values ​​in compressive and tensile strength are almost 3 times the improved values ​​reported for other graphene / cement composites with the same graphene loading.

[0362] Figures 20A-20B is a SEM image of a CB-FG / cement composite, which shows the uniform distribution of FG in the cement matrix. The large improvement in the performance of the CB-FG / cement composite is also believed to be caused by the high dispersibility of the turbostratic CB-FG, which produces a uniform and stable composite. The uniformly distributed flake FG can act as a template to promote the uniform growth of cement hydration products. 29 [Moghaddam 2017]. In addition, there is literature evidence that covalent CO bonds / networks between graphene and cement hydration products can be formed by covalent bonding to hybridize graphene from sp 2 Change to sp 3 , which significantly improves the mechanical properties of the composites. [Hosseini 2019]. This change, along with the release of electrons near their interfacial regions [Hosseini 2019], can lead to homogeneous, intermixed and intercalated composites with improved properties.

[0363] Additionally, CB-FG is an effective polymer performance enhancer; further demonstrating the enhancements observed from the ease with which turbostratic graphene can be exfoliated relative to other stacking arrangements such as AB stacking. Fig.21 As shown, the 0.1 wt % CB-FG / polydimethylsiloxane (PDMS) composite exhibits an increase of about 250% in compressive strength over PDMS without graphene.

[0364] C-FG and FG obtained from calcined coke are also used as electrode materials in Li-ion capacitors and Li-ion batteries.

[0365] Battery

[0366] The electrochemical performance of FG was tested in a CR2032 cell. All cells were assembled in a glove box under an argon atmosphere. The CR2032 lithium-ion cell included a lithium foil as a counter electrode, Celgard K2045 as a separator, 1M lithium hexafluorophosphate (LiPF6) (MTI corporation) dissolved in 1:1:1 ethylene carbonate: dimethyl carbonate: diethyl carbonate (EC: DMC: DEC) as an electrolyte, and FG (C-FG and CC-FG) as a cathode / anode. The cathode / anode was prepared by pouring a slurry (which had 80wt% active material, 10wt% (Super P, TIMCAL) and 10wt% polyvinylidene fluoride (PVDF; Alfa Aesar) in N-methyl-2-pyrrolidone (NMP) onto a piece of Al / Cu foil. The constant current discharge / charge tests were performed in the voltage range of 0.01-3.0V (compared to Li+ / Li) for the anode and 1.0-3.5V (compared to Li+ / Li) for the cathode, respectively. The full capacitor performance of the flashed graphene in the Li-ion capacitor was tested in a CR2032 cell. To assemble the FG Li-ion capacitor, the anode and cathode of the Li-ion battery half-cell were cycled several times, and the anode was in the discharged state and the cathode was in the charged state. The two cells were opened inside the glove box, reassembled as FG Li-ion capacitors, and tested in the voltage range of 0.1-3.5V. The capacity of the Li-ion capacitor was calculated based on the total mass of the anode plus the cathode from the Li-ion battery.

[0367] Figures 22A-22H is a diagram showing FG in a Li ion capacitor and a Li ion battery. A Li ion battery was manufactured and cycled, then opened, and a Li ion capacitor was manufactured using the anode and cathode. Fig.22A The charge / discharge curves of a Li-ion battery with a C-FG anode (0.01-3.0 V) (curve 2202) and a cathode (1-3.5 V) (curve 2201) in a half-cell are shown, with Li foil as counter and reference electrodes. Fig. 22B The C-FG Li-ion capacitor is shown at 20 mA.g -1 Figures 2203-2204 are for charge and discharge, respectively. Inset 2205 shows the change in voltage over time during the 20th and 21st cycles. Fig. 22C The Li-ion battery with a C-FG cathode half-cell is shown at 30 mA.g-1 Figures 2206-2207 are for charging and discharging, respectively. Fig.22D The Li-ion battery with CC-FG as the anode half-cell is shown at 50 mA.g -1 Figures 2208-2209 are for charging and discharging, respectively.

[0368] Fig.22E The charge / discharge curves of a Li-ion battery with a calcined coke-FG (CC-FG) anode (0.01-3.0 V) (curve 2211) and a cathode (1-3.5 V) (curve 2210) in a half-cell are shown, with Li foil as the counter electrode and reference electrode. Fig.22F shows the CC-FG Li-ion capacitor at 5mA.g -1 Figures 2212-2213 are for charge and discharge, respectively. Inset 2214 shows the change in voltage over time during the 20th and 21st cycles. Figure 22G The Li-ion battery with CC-FG as cathode was shown at 25 mA.g -1 Figures 2215-2216 are for charging and discharging, respectively. Fig.22H The Li-ion battery with CC-FG as anode is shown at 100 mA.g -1 Figures 2217-2218 are for charging and discharging, respectively.

[0369] The Li-ion battery from two FGs has a capacity of about 200 mAh g -1 gravimetric capacity, while they show that the cathode gravimetric capacities of C-FG and FG obtained from calcined coke are about 15 mAh·g -1 and about 10mAh·g -1 Even though the energy density of the Li-ion capacitor is only about 10Wh·kg -1 , but the results show the use of FG made from abundant and waste resources in advanced energy applications.

[0370] Carbon Black-Rubber FG

[0371] Using the protocol described above for converting waste plastic feedstock, a blend of 5% carbon black in combination with shredded tires was converted to flash graphene. Table IV below reflects the FJH parameters.

[0372] Table IV

[0373]

[0374] Figures 23A-23B They are the Raman spectrum and Raman map of CB-rubber FG, respectively.

[0375] Figures 24A-24B XRD and Raman spectra of 5% CB-rubber FG, 5% CB-rubber (200ms) FG, 5% CB-rubber (300ms) FG and 5% CB-rubber (400ms) FG, respectively. The XRD shows characteristic peaks of graphene, and the intensity of some dimensional lines increases.

[0376] 2D Materials

[0377] 2D materials (including non-graphene 2D materials) can be prepared by applying one or more voltage pulses (i.e., flash Joule heating) across their respective precursors. This flash Joule heating enables millisecond-scale synthesis of 2D materials (including some metastable phase materials), which is almost impossible to do directly by CVD or hydrothermal methods without the help of any reagents. And the price of the FJH synthesis strategy is significantly cheaper, and the range of 2D materials that can be manufactured is greatly expanded, which is also beneficial to many industrial applications. There are many applications based on the synthesized materials. For example, 1T'-MoS2 has higher catalytic activity and better energy storage performance than 2H-MoS2. [Yu 2018; Chang 2016; Acerce 2015]

[0378] For the preparation of 2D materials, if the precursor is conductive and the conductivity is greater than 10 -6 S / cm, one or more voltage pulses can be applied directly. If the precursor is non-conductive and the conductivity is less than 10 -7 S / cm, the precursor can be mixed with some carbon material or metal powder to increase the conductivity.

[0379] The pulse length is usually 1 microsecond to 5 seconds, and more particularly 10 milliseconds to 1000 milliseconds. The number of pulses is usually 1 pulse to 100 pulses, and more particularly 1 pulse to 10 pulses. The current is usually 0.01 A / cm 2 Up to 10000A / cm 2 , and more particularly 0.1 A / cm 2 Up to 1000A / cm 2 The voltage is typically 10V to 4000V, and more particularly 100V to 400V.

[0380] The conductive precursor may include iron powder, molybdenum powder, tungsten metal, copper metal and other metal sources. Non-metallic materials include carbon black, calcined petroleum coke and other carbon materials. Non-conductive power sources include molybdenum disulfide (MoS2), ammonium tetrathiomolybdate ((NH4)2MoS4), borane ammonia complex (BH3NH3), red phosphorus and other respective precursors. The non-conductive power source may be mixed with the conductive power source specified above to achieve the conductivity in the range specified above.

[0381] If the starting material is molybdenum disulfide or ammonium tetrathiomolybdate, they can be converted into different forms of MoS2, such as 1T'-MoS2 and 2H-MoS2. If the starting material is a borane ammonia complex, they can be converted into hexagonal boron nitride (h-BN). If the starting material is red phosphorus, black phosphorus can be obtained.

[0382] like Figure 1A and 2A The FJH system shown in can be used to make 2D materials. For conductive precursors, they can be placed directly in the quartz tube 101 for flash heating treatment. For non-conductive precursors, they can first be mixed with conductive carbon materials or metals and ground in a mortar. Then they can be treated like conductive precursors. For some specific precursors such as red phosphorus, due to the presence of surface oxides, NaOH and distilled water are first used to wash these precursors and remove oxides before processing.

[0383] The precursor samples with the copper fleece 202 facing flat on both sides are compressed in the quartz tube 101 and the capacitor 210 is discharged through the respective precursor. This raises the temperature to a wide range (800K to 3000K), which depends on the flash Joule heater settings. The discharge is typically completed in 10-1000 milliseconds. The temperature range and discharge time make it possible to synthesize many different kinds of 2D or other materials in a short period of time. This method can be repeated 2-5 times as needed to increase the quality and quantity of the respective 2D materials. The discharge is performed in a low vacuum chamber to avoid affecting the oxygen and other gases in the formation atmosphere.

[0384] As examples, this FJH method was used to (i) convert (NH4)2MoS4 into 2H-MoS2 and 1T′-MoS2, (ii) convert commercial 2H-MoS2 into 1T′-MoS2, and (iii) convert BH3NH3 into h-BN.

[0385] Fig.25A Figures 2501-2506 correspond to the reactants and flash times of 50 ms, 200 ms, 250 ms, 300 ms and 400 ms, respectively. By Raman spectroscopy, the J series peak J1 (156 cm -1 ), J2(218cm -1 ) and J3(335cm -1 ) is the characteristic peak of 1T'-MoS2, and E 2g Peak (380cm -1 ) is the characteristic peak of 2H-MoS2. [Yu 2018]. Fig.25BIt is the yield of MoS2 by flash heating at different flash times. Fig.25C is the difference between J3 and E at different flash times 2g Peak intensity ratio. It can be seen that the correct flash time is the key factor in converting 2H-MoS2 into 1T'-MoS2. If too long a pulse time is used, MoS2 still remains in the thermodynamically stable phase (2H-MoS2). And by controlling the pulse time between 50 milliseconds and 250 milliseconds, a good quality metastable 1T'-MoS2 phase can be obtained in good yield.

[0386] Compared with 229.6eV (3d 5 / 2 ) and 232.1eV(3d 3 / 2 ) compared to 1T'-MoS2 which has 228.1eV (3d 5 / 2 ) and 231.1eV(3d 3 / 2 ) has a lower binding energy. [Yu 2018]. Fig.26 As shown (XPS Mo 3d spectra of flash-heated MoS2 using different flash times, and Figures Q1901-Q1904 correspond to the reactants and 50ms, 300ms and 400ms flash times, respectively), a shift to lower binding energy was observed by using a flash time of 50ms to 300ms, which means the presence of 1T'-MoS2 phase in the sample and is consistent with the results of Raman spectroscopy.

[0387] like Fig. 27 As shown in (XRD of 2H-MoS2 and 1T'-MoS2), the comparison between 1T'-MoS2 and 2H-MoS2 shows that the (002) peak is 14 o shifted to high angles, which is the same as shown in the literature. [Yu2018]. In addition, the intensity of (002) of our 1T'-MoS2 sample is significantly lower, which means that a few-layer product is obtained and is consistent with Figures 28A-28B The TEM image is consistent with that of Figures 28A-28B , a clear pattern of MoS2 edge can be seen, and by checking the intensity curve data, the interlayer distance is about 0.62nm, which is 3% smaller than that of 2H-MoS2, which is consistent with the XRD shown in Figure 20. And most areas of the sample contain few layers of MoS2. In addition, the edge angle is about 120o, which is very important for knowing the atomic arrangement and the performance of the sample in some applications such as catalysts.

[0388] Boron nitride is also used in the flash heating method. To increase the conductivity of the precursor, some conductive carbon black is added. Fig.29 Figure 2 is the Raman spectra of flash graphene (FG) and different boron nitride (BN) samples. After the flash process, the Raman spectra of the BN samples have a peak of ∼10 cm-1 This indicates that it is the flash graphene D peak (~1350cm -1 ) and h-BNE 2g Peak (~1369cm -1 ). [Wang 2017].

[0389] Figures 30A-30B The XPS B 1s and N1s spectra of the boron nitride sample are shown in Table V. The peak position measurements of B1s and N1s are shown in Table V.

[0390] Table V

[0391] peak B N 1 190.9eV(BN) 398.6eV(NB) 2 192.5eV(BC=O) 400.3eV(N-C)

[0392] The splitting of the B 1s and N 1s spectra inferred the formation of new materials, and Raman and XPS supported the formation of such boron nitride by flash heating [Wang 2017].

[0393] In summary, the present invention provides a low-energy bottom-up synthesis of easily exfoliated graphene from ultra-low-cost carbon sources such as coal and petroleum coke, renewable resources such as biochar, and mixed waste products (including plastic bottles and discarded food). This allows for large-scale carbon fixation while providing recycled carbon for bulk building composites enhanced by graphene.

[0394] The present invention also provides the following embodiments.

[0395] 1. A method comprising synthesizing graphene by applying a voltage pulse across a conductive carbon source that is not substantially graphene.

[0396] 2. The method according to embodiment 1, wherein the conductivity of the conductive carbon source is greater than 10 -5 S / cm.

[0397] 3. The method according to embodiment 2, wherein the conductivity of the conductive carbon source is greater than 10 -3 S / cm.

[0398] 4. The method according to embodiment 1, wherein the duration of the voltage pulse is 1 microsecond to 5 seconds.

[0399] 5. The method according to embodiment 4, wherein the duration of the voltage pulse is 100 milliseconds to 500 milliseconds.

[0400] 6. The method according to embodiment 1, wherein the voltage pulse is repeated 2 to 100 times.

[0401] 7. A method according to embodiment 6, wherein the voltage pulse is repeated 2 to 10 times.

[0402] 8. The method according to embodiment 1, wherein the current across the sample is 0.01A / cm 2 Up to 10000A / cm 2 .

[0403] 9. The method of embodiment 8, wherein the current across the sample is 0.1 A / cm 2 Up to 1000A / cm 2 .

[0404] 10. The method of embodiment 1, wherein the voltage across the sample is 10 V / cm to 4000 V / cm.

[0405] 11. The method of embodiment 10, wherein the voltage across the sample is 100 V / cm to 400 V / cm.

[0406] 12. The method according to embodiment 1, wherein the conductive carbon source is selected from anthracite, biochar treated at a higher temperature, calcined petroleum coke, shungite, carbon nanotubes, asphaltene, acetylene black, carbon black and mixtures thereof.

[0407] 13. The method of embodiment 1, wherein the conductive carbon source comprises a conductive carbon source additive, the conductive carbon source additive providing the conductive carbon source with sufficient conductivity for use in the method.

[0408] 14. The method of embodiment 13, wherein:

[0409] (a) the conductive carbon source additive is selected from anthracite, biochar treated at a relatively high temperature, calcined petroleum coke, carbon nanotubes, graphene quantum dots, acetylene black, carbon black, shungite, graphene or a mixture thereof;

[0410] (b) the conductive carbon source is a relatively low conductivity carbon material selected from the group consisting of feces, plastics, vinyl polymers, condensation polymers, step-growth polymers, chain-growth polymers, activated polymers, rubber, humic acid, carbohydrates, rice flour, food waste, food, coal, organic waste, organic materials, bituminous coal, coke, petroleum coke, petroleum, petroleum products, carbon from natural gas or petroleum or carbon dioxide with non-carbon atoms removed, wood, cellulose, leaves, branches, grass, biomass, animal carcasses, fish carcasses, proteins, and mixtures thereof; and

[0411] (c) adding the conductive carbon source additive to the lower conductivity carbon material so that the lower conductivity source has sufficient conductivity for use in the method.

[0412] 15. The method of embodiment 1, wherein prior to the method, the conductive carbon source comprises less than 50% graphene.

[0413] 16. The method of embodiment 15, wherein prior to the method, the conductive carbon source contains substantially no spectroscopically detectable graphene.

[0414] 17. The method of embodiment 1, wherein the product yield of the method comprises at least 70% graphene.

[0415] 18. The method of embodiment 17, wherein the product yield is at least 90% graphene.

[0416] 19. The method of embodiment 17, wherein the product yield is 100% graphene.

[0417] 20. The method of embodiment 19, wherein the synthesized graphene is turbostratic graphene.

[0418] 21. The method of embodiment 1, wherein the conductive carbon source comprises:

[0419] (a) The conductivity is at most 10 -7 S / cm of carbon source; and

[0420] (b) a conductive carbon source additive intermixed with the carbon source, wherein the conductivity of the conductive carbon source is at least 10 -5 S / cm.

[0421] 22. The method according to embodiment 21, wherein the conductivity of the conductive carbon source is at least 10 -3 S / cm.

[0422] 23. The method according to embodiment 21, wherein the conductive carbon source additive is selected from carbon black, metal powder and combinations thereof.

[0423] 24. The method of embodiment 1, wherein the method is a continuous method.

[0424] 25. The method of embodiment 1, wherein the method is an automated method.

[0425] 26. The method of embodiment 1, wherein the conductive carbon source comprises carbon black and rubber.

[0426] 27. The method of embodiment 26, wherein the conductive carbon source comprises 1 wt% to 10 wt% carbon black.

[0427] 28. The method of embodiment 27, wherein the conductive carbon source comprises 4 wt% to 6 wt% carbon black.

[0428] 29. The method of embodiment 1, wherein the step of applying a voltage pulse uses a DC voltage.

[0429] 30. The method of embodiment 1, wherein the method of applying voltage pulses uses an AC voltage.

[0430] 31. A method according to embodiment 1, wherein the voltage pulse is applied using a power supply, and the power supply uses three-phase electrical power.

[0431] 32. A method comprising synthesizing graphene by applying a voltage pulse across a conductive carbon source that is not substantially graphene, wherein heteroatoms are present when the voltage pulse is applied across the conductive carbon source to provide a doped or heteroatom-containing graphene product.

[0432] 33. A method according to embodiment 32, wherein the heteroatom is selected from nitrogen, phosphorus, boron and mixtures thereof.

[0433] 34. The method of embodiment 32, wherein the heteroatom is selected from metals, semi-metals, and mixtures thereof.

[0434] 35. The method of embodiment 32, wherein the heteroatom source is selected from melamine, aminoborane, melamine-formaldehyde resin, phosphine, phosphate, metal salt, metal oxide and mixtures thereof.

[0435] 36. An apparatus comprising:

[0436] (a) a carbon feedstock comprising a conductive carbon source that is substantially not graphene;

[0437] (b) a non-conductive container operable to confine the conductive carbon source; and

[0438] (c) an electrode operable to apply a voltage pulse across the conductive carbon source within the non-conductive container to synthesize graphene.

[0439] 37. The apparatus of embodiment 36, wherein the apparatus further comprises a conduit through which the electrically conductive carbon source can be transported to the non-conductive container.

[0440] 38. An apparatus according to embodiment 36, wherein the apparatus further comprises a chamber, and the non-conductive container can be located in the chamber when the electrode applies a voltage pulse.

[0441] 39. An apparatus according to embodiment 36, wherein the non-conductive container comprises quartz or ceramic material.

[0442] 40. The apparatus of embodiment 36, wherein the non-conductive container comprises a quartz tube.

[0443] 41. The apparatus of embodiment 36, wherein:

[0444] (a) the device comprises a plurality of the non-conductive containers; and

[0445] (b) the apparatus further comprises a belt or screw and a collection box; and

[0446] (c) the belt or screw is operable to:

[0447] (i) after the conductive carbon source is filled in the non-conductive container, transferring the container among the plurality of the non-conductive containers into the chamber; and

[0448] (ii) transporting the non-conductive container out of the chamber to a location where the synthesized graphene can be collected in the collection box.

[0449] 42. An apparatus according to embodiment 36, wherein the apparatus comprises a plurality of capacitors operable to apply the voltage pulses.

[0450] 43. An apparatus according to embodiment 36, wherein the apparatus comprises a controller and a mechanical relay operable to control the application of the voltage pulses.

[0451] 44. An apparatus according to embodiment 43, wherein the apparatus comprises an inductor and a diode operatively connected to a controller and a mechanical relay.

[0452] 45. The apparatus of embodiment 36, wherein the apparatus further comprises a disconnect switch.

[0453] 46. ​​The apparatus of embodiment 36, wherein the conductive carbon source comprises a conductive carbon source having a conductivity of at least 10 -5 S / cm of carbon source.

[0454] 47. The apparatus of embodiment 46, wherein the conductivity of the carbon source is at least 10 -3 S / cm.

[0455] 48. An apparatus according to embodiment 36, wherein the conductive carbon source comprises a carbon source and a conductive carbon source additive.

[0456] 49. The apparatus of embodiment 48, wherein the conductive carbon source is carbon powder.

[0457] 50. The apparatus of embodiment 49, wherein:

[0458] (a) the electrical conductivity of the carbon source is at least at most 10 -6 S / cm; and

[0459] (b) the electrical conductivity of the conductive carbon source is at least 10 -5 S / cm.

[0460] 51. The apparatus of embodiment 50, wherein the conductivity of the conductive carbon source is at least 10 -3 S / cm.

[0461] 52. An apparatus according to embodiment 36, wherein the apparatus is operable to perform a continuous method for synthesizing graphene from the conductive carbon source.

[0462] 53. An apparatus according to embodiment 36, wherein the apparatus is operable to perform an automated method for synthesizing graphene from the conductive carbon source.

[0463] 54. A system comprising the apparatus according to embodiment 36.

[0464] 55. A system according to embodiment 54, wherein the device is operably connected to a DC voltage source.

[0465] 56. A system according to embodiment 54, wherein the device is operably connected to an AC voltage source.

[0466] 57. A system according to embodiment 54, wherein the device is operably connected to a power source using three-phase electrical power.

[0467] 58. A system according to embodiment 57, wherein the power supply uses three-phase electrical power followed by full-wave rectification.

[0468] 59. A system according to embodiment 57, wherein the power supply uses a zero-crossing relay to control the duration of the voltage pulse.

[0469] 60. The system of embodiment 59, wherein the power supply further comprises a computer control, wherein the computer control is operable to select a duration of the voltage pulse based on a number of half cycles allowed through the zero-crossing relay.

[0470] 61. A system according to embodiment 57, wherein the power supply is operable to use one of 120, 208, 277, 480 volts AC (RMS) root mean square three phases.

[0471] 62. The system of embodiment 57, wherein the power source comprises a three-phase generator operable to provide AC power.

[0472] 63. A system according to embodiment 62, wherein the three-phase generator is mechanically connected to an AC motor.

[0473] 64. The system of embodiment 62, wherein:

[0474] (a) the three-phase generator comprises a rotor; and

[0475] (b) The three-phase generator is operable to provide AC power by rapidly converting mechanical power into electric current due to the inertia of the rotor.

[0476] 65. The system of embodiment 62, wherein:

[0477] (a) the three-phase generator comprises a flywheel; and

[0478] (b) The three-phase generator is operable to provide AC power using the flywheel to provide a longer duration and stable voltage and current output.

[0479] 66. The system of embodiment 54, wherein:

[0480] (a) the apparatus comprises a plurality of capacitors operable to apply the voltage pulses; and

[0481] (b) The apparatus comprises a controller and a mechanical relay operable to control the application of the voltage pulses.

[0482] 67. An apparatus according to embodiment 66, wherein the apparatus comprises an inductor and a diode operatively connected to a controller and a mechanical relay.

[0483] 68. The apparatus of embodiment 54, wherein the apparatus further comprises a disconnect switch.

[0484] 69. A method of forming a 2D material, wherein the method comprises:

[0485] (a) selecting a precursor material comprising a precursor;

[0486] (b) Applying a voltage pulse across the material to form the 2D material.

[0487] 70. The method according to embodiment 69, wherein the conductivity of the precursor is greater than 10 -6 S / cm.

[0488] 71. The method of embodiment 70, wherein the precursor comprises a metal source.

[0489] 72. The method of embodiment 71, wherein the metal source is selected from iron powder, molybdenum powder, tungsten metal and copper metal.

[0490] 73. A method according to embodiment 70, wherein the precursor comprises a non-metallic source.

[0491] 74. A method according to embodiment 73, wherein the non-metal source is selected from carbon black and calcined petroleum coke.

[0492] 75. The method of embodiment 69, wherein:

[0493] (a) The electrical conductivity of the precursor is less than 10 -6 S / cm;

[0494] (b) the precursor material further comprises a conductive source; and

[0495] (c) The electrical conductivity of the precursor material is greater than 10 -5 S / cm.

[0496] 76. The method according to embodiment 75, wherein the conductivity of the precursor is less than 10 -7 S / cm.

[0497] 77. A method according to embodiment 75, wherein the precursor is selected from molybdenum disulfide (MoS2), ammonium tetrathiomolybdate ((NH4)2MoS4), borane ammonia complex (BH3NH3), red phosphorus and combinations thereof.

[0498] 78. A method according to embodiment 75, wherein the conductive source is selected from carbon materials, metal powders and combinations thereof.

[0499] 79. A method according to embodiment 69, wherein the precursor is selected from molybdenum disulfide (MoS2), ammonium tetrathiomolybdate ((NH4)2MoS4), borane ammonia complex (BH3NH3), red phosphorus and combinations thereof.

[0500] 80. A method according to embodiment 69, wherein the precursor comprises molybdenum disulfide (MoS2) or ammonium tetrathiomolybdate ((NH4)2MoS4).

[0501] 81. A method according to embodiment 80, wherein the 2D material comprises 1T'-MoS2 and 2H-MoS2.

[0502] 82. A method according to embodiment 69, wherein the precursor comprises a borane ammonia complex (BH3NH3).

[0503] 83. A method according to embodiment 82, wherein the 2D material comprises hexagonal boron nitride (h-BN).

[0504] 84. The method of embodiment 69, wherein the precursor comprises red phosphorus.

[0505] 85. A method according to embodiment 84, wherein the 2D material comprises black phosphorus.

[0506] 86. The method of embodiment 69, wherein the step of applying a voltage pulse across the material to form the 2D material comprises:

[0507] (a) applying a number of voltage pulses across the material, wherein the number of voltage pulses is from 1 pulse to 100 pulses;

[0508] (b) the duration of each of the voltage pulses is from 1 microsecond to 5 seconds;

[0509] (c) The current of each voltage pulse is 0.01A / cm 2 Up to 10000A / cm 2 ;and

[0510] (d) The voltage of each of the voltage pulses is 10V to 4000V.

[0511] 87. The method of embodiment 86, wherein:

[0512] (a) the number of the voltage pulses is 1 pulse to 10 pulses;

[0513] (b) the duration of each of the voltage pulses is 10 microseconds to 1000 milliseconds;

[0514] (c) The current of each voltage pulse is 0.1A / cm 2 Up to 1000A / cm 2 ;and

[0515] (d) The voltage of each of the voltage pulses is 100V to 400V.

[0516] 88. A method according to embodiment 69, wherein the step of applying a voltage pulse uses a DC voltage.

[0517] 89. A method according to embodiment 69, wherein the step of applying a voltage pulse uses an AC voltage.

[0518] 90. A method according to embodiment 69, wherein the voltage pulses are applied using a power supply, and the power supply uses three-phase electrical power.

[0519] 91. An apparatus comprising:

[0520] (a) a precursor material comprising a precursor;

[0521] (b) a non-conductive container operable to confine the precursor material; and

[0522] (c) an electrode operable to apply a voltage pulse across the precursor material within the non-conductive container to produce a 2D material.

[0523] 92. An apparatus according to embodiment 91, wherein the apparatus further comprises a pipeline through which the precursor can be transported to the non-conductive container.

[0524] 93. An apparatus according to embodiment 91, wherein the apparatus further comprises a chamber, and when the electrode applies a voltage pulse, the non-conductive container can be located in the chamber.

[0525] 94. An apparatus according to embodiment 91, wherein the non-conductive container comprises quartz or ceramic material.

[0526] 95. The apparatus of embodiment 91, wherein:

[0527] (a) the device comprises a plurality of the non-conductive containers;

[0528] (b) the apparatus further comprises a belt or screw and a collection box; and

[0529] (c) the belt or screw is operable to:

[0530] (i) after the precursor material is filled in the non-conductive container, transporting the non-conductive container among the plurality of non-conductive containers into the chamber; and

[0531] (ii) transporting the non-conductive container out of the chamber to a location where the prepared 2D material can be collected in the collection box.

[0532] 96. An apparatus according to embodiment 91, wherein the apparatus comprises a plurality of capacitors operable to apply voltage pulses.

[0533] 97. An apparatus according to embodiment 91, wherein the apparatus comprises a controller and a mechanical relay operable to control the application of the voltage pulses.

[0534] 98. An apparatus according to embodiment 97, wherein the apparatus comprises an inductor and a diode operatively connected to a controller and a mechanical relay.

[0535] 99. An apparatus according to embodiment 91, wherein the apparatus further comprises a disconnect switch.

[0536] 100. The apparatus of embodiment 91, wherein the conductivity of the precursor is at least 10 -5 S / cm.

[0537] 101. The apparatus of embodiment 100, wherein the conductivity of the precursor is at least 10 -3 S / cm.

[0538] 102. An apparatus according to embodiment 91, wherein the precursor material further comprises a conductive source.

[0539] 103. The apparatus of embodiment 102, wherein:

[0540] (a) the electrical conductivity of the precursor is at least at most 10 -6 S / cm; and

[0541] (b) the conductivity of the conductive source is at least 10 -5 S / cm.

[0542] 104. The apparatus of embodiment 103, wherein the conductivity of the precursor material is at least 10 -3 S / cm.

[0543] 105. An apparatus according to embodiment 91, wherein the apparatus is operable to carry out a continuous method for producing a 2D material from the precursor material.

[0544] 106. An apparatus according to embodiment 91, wherein the apparatus is operable to perform an automated method for producing a 2D material from the precursor material.

[0545] 107. A system comprising the apparatus according to embodiment 91.

[0546] 108. A system according to embodiment 107, wherein the device is operably connected to a DC voltage source.

[0547] 109. A system according to embodiment 107, wherein the device is operably connected to an AC voltage source.

[0548] 110. A system according to embodiment 107, wherein the device is operably connected to a power source using three-phase electrical power.

[0549] 111. A system according to embodiment 110, wherein the power supply uses three-phase electrical power followed by full-wave rectification.

[0550] 112. The system of embodiment 110, wherein the power supply uses a zero-crossing relay to control the duration of the voltage pulse.

[0551] 113. The system of embodiment 112, wherein the power supply further comprises a computer control, wherein the computer control is operable to select a duration of the voltage pulse based on a number of half cycles allowed through the zero-crossing relay.

[0552] 114. A system according to embodiment 110, wherein the power supply is operable to use one of 120, 208, 277, 480 volts AC (RMS) root mean square three phases.

[0553] 115. The system of embodiment 110, wherein the power source comprises a three-phase generator operable to provide AC power.

[0554] 116. A system according to embodiment 115, wherein the three-phase generator is mechanically connected to an AC motor.

[0555] 117. The system of embodiment 115, wherein:

[0556] (a) the three-phase generator comprises a rotor; and

[0557] (b) The three-phase generator is operable to provide AC power by rapidly converting mechanical power into electric current due to the inertia of the rotor.

[0558] 118. The system of embodiment 115, wherein:

[0559] (a) the three-phase generator comprises a flywheel; and

[0560] (b) The three-phase generator is operable to provide AC power using the flywheel to provide a longer duration and stable voltage and current output.

[0561] 119. The system of embodiment 107, wherein:

[0562] (a) the apparatus comprises a plurality of capacitors operable to apply the voltage pulses; and

[0563] (b) The apparatus comprises a controller and a mechanical relay operable to control the application of the voltage pulses.

[0564] 120. A system according to embodiment 119, wherein the device comprises an inductor and a diode operatively connected to a controller and a mechanical relay.

[0565] 121. The system of embodiment 107, wherein the device further comprises a disconnect switch.

[0566] 122. A method comprising synthesizing large quantities of turbostratic graphene.

[0567] 123. A method according to embodiment 122, wherein the method includes a flash graphene process to produce turbostratic graphene from carbon-based materials.

[0568] 124. A method according to embodiment 122, wherein the turbostratic graphene is low-defect turbostratic graphene.

[0569] 125. The method of embodiment 122, further comprising making a composite material using the turbostratic graphene.

[0570] 126. A method comprising synthesizing turbostratic graphene by applying a voltage pulse across a conductive carbon source that is not substantially graphene.

[0571] 127. The method of embodiment 126, wherein the conductivity of the conductive carbon source is greater than 10 -5 S / cm.

[0572] 128. The method of embodiment 127, wherein the conductivity of the conductive carbon source is greater than 10 -3 S / cm.

[0573] 129. A method according to embodiment 126, wherein the duration of the voltage pulse is 1 microsecond to 5 seconds.

[0574] 130. A method according to embodiment 129, wherein the duration of the voltage pulse is 100 milliseconds to 500 milliseconds.

[0575] 131. A method according to embodiment 126, wherein the voltage pulse is repeated 2 to 100 times.

[0576] 132. A method according to embodiment 131, wherein the voltage pulse is repeated 2 to 10 times.

[0577] 133. The method of embodiment 126, wherein the current across the sample is 0.01 A / cm 2 Up to 10000A / cm 2 .

[0578] 134. A method according to embodiment 133, wherein the current across the sample is 0.1A / cm 2 Up to 1000A / cm 2 .

[0579] 135. A method according to embodiment 126, wherein the voltage across the sample is 10V / cm to 4000V / cm.

[0580] 136. A method according to embodiment 135, wherein the voltage across the sample is 100 V / cm to 400 V / cm.

[0581] 137. The method of embodiment 126, wherein the conductive carbon source is selected from anthracite, biochar treated at a higher temperature, calcined petroleum coke, shungite, carbon nanotubes, asphaltene, acetylene black, carbon black, and mixtures thereof.

[0582] 138. A method according to embodiment 126, wherein the conductive carbon source contains a conductive carbon source additive, which makes the conductive carbon source have sufficient conductivity for use in the method.

[0583] 139. The method of embodiment 138, wherein:

[0584] (a) the conductive carbon source additive is selected from anthracite, biochar treated at a relatively high temperature, calcined petroleum coke, carbon nanotubes, graphene quantum dots, acetylene black, carbon black, shungite, graphene or a mixture thereof;

[0585] (b) the conductive carbon source is a relatively low conductivity carbon material selected from the group consisting of feces, plastics, vinyl polymers, condensation polymers, step-growth polymers, chain-growth polymers, activated polymers, rubber, humic acid, carbohydrates, rice flour, food waste, food, coal, organic waste, organic materials, bituminous coal, coke, petroleum coke, petroleum, petroleum products, carbon from natural gas or petroleum or carbon dioxide with non-carbon atoms removed, wood, cellulose, leaves, branches, grass, biomass, animal carcasses, fish carcasses, proteins, and mixtures thereof; and

[0586] (c) adding the conductive carbon source additive to the lower conductivity carbon material so that the lower conductivity source has sufficient conductivity for use in the method.

[0587] 140. The method of embodiment 126, wherein the conductive carbon source comprises:

[0588] (a) The conductivity is at most 10 -7 S / cm of carbon source; and

[0589] (b) a conductive carbon source additive intermixed with the carbon source, wherein the conductivity of the conductive carbon source is at least 10 -5 S / cm.

[0590] 141. The method of embodiment 140, wherein the conductivity of the conductive carbon source is at least 10 -3 S / cm.

[0591] 142. A method according to embodiment 141, wherein the conductive carbon source additive is selected from carbon black, metal powder and combinations thereof.

[0592] 143. The method of embodiment 126, wherein the method is a continuous method.

[0593] 144. The method of embodiment 126, wherein the method is an automated method.

[0594] 145. The method of embodiment 126, wherein:

[0595] (a) the method synthesizes at least 1 g of bulk graphene material; and

[0596] (b) the turbostratic graphene is at least 90 wt % of the bulk graphene material.

[0597] 146. A bulk graphene material, wherein:

[0598] (a) a majority of the bulk graphene material is turbostratic graphene; and

[0599] (b) The weight of the bulk graphene material is at least 1 g.

[0600] 147. A bulk graphene material according to embodiment 146, wherein at least 90 wt% of the graphene is turbostratic graphene.

[0601] 148. The bulk graphene material of embodiment 146, wherein:

[0602] (a) the bulk graphene material is synthesized from a carbon source material mainly comprising a solid carbon source, and

[0603] (b) The solid carbon source is a solid carbon source.

[0604] 149. A bulk graphene material according to embodiment 148, wherein the solid carbon source accounts for at least 90 wt% of the carbon source material.

[0605] 150. The bulk graphene material of embodiment 146, wherein:

[0606] (a) the bulk graphene material is synthesized from a carbon source material mainly comprising a liquid carbon source, and

[0607] (b) The liquid carbon source is a liquid carbon source.

[0608] 151. A bulk graphene material according to embodiment 150, wherein the liquid carbon source accounts for at least 90 wt% of the carbon source material.

[0609] 152. A composite material comprising turbostratic graphene and a second material.

[0610] 153. A composite material according to embodiment 152, wherein the second material is selected from concrete, cement, plastic, paint, coating, foam, polyurethane foam, flooring materials, roofing materials, wood, plywood, aluminum, steel, copper, metal, asphalt, metal oxides, carbon-carbon composites, fibers, membranes and combinations thereof.

[0611] 154. A composite material according to embodiment 152, wherein the composite material comprises 0.001 wt% to 10 wt% of turbostratic graphene.

[0612] 155. A composite material according to embodiment 152, wherein the tensile strength of the composite material is greater than the tensile strength of the second material without the turbostratic graphene.

[0613] 156. A composite material according to embodiment 155, wherein the tensile strength of the composite material is at least 10% greater than the tensile strength of the second material without the turbostratic graphene.

[0614] 157. A composite material according to embodiment 152, wherein the compressive strength of the composite material is greater than the compressive strength of the second material without the turbostratic graphene.

[0615] 158. A composite material according to embodiment 157, wherein the compressive strength of the composite material is at least 10% greater than the compressive strength of the second material without the turbostratic graphene.

[0616] 159. A composite material according to embodiment 152, wherein the Young's modulus of the composite material is significantly different from the Young's modulus of the second material without the turbostratic graphene.

[0617] 160. A composite material according to embodiment 159, wherein the Young's modulus of the composite material differs by at least 10% from the Young's modulus of the second material without the turbostratic graphene.

[0618] 161. A composite material according to embodiment 152, wherein the yield strength of the composite material is greater than the yield strength of the second material without the turbostratic graphene.

[0619] 162. A composite material according to embodiment 160, wherein the yield strength of the composite material is at least 10% greater than the yield strength of the second material without the turbostratic graphene.

[0620] 163. A composite material according to embodiment 152, wherein the electrical conductivity of the composite material is greater than the electrical conductivity of the second material without the turbostratic graphene.

[0621] 164. A composite material according to embodiment 163, wherein the conductivity of the composite material is at least 10 Siemens / cm greater than the conductivity of the second material without the turbostratic graphene.

[0622] 165. A composite material according to embodiment 152, wherein the thermal conductivity of the composite material is greater than the thermal conductivity of the second material without the turbostratic graphene.

[0623] 166. A composite material according to embodiment 165, wherein the thermal conductivity of the composite material is at least 1 W / m-Kelvin higher than the thermal conductivity of the second material without the turbostratic graphene.

[0624] 167. A composite material according to embodiment 152, wherein the second material is a liquid material.

[0625] 168. A composite material according to embodiment 167, wherein the liquid material is selected from coolant, transmission fluid, lubricant, oil and combinations thereof.

[0626] 169. A composite material according to embodiment 167, wherein the liquid material is selected from drilling fluid and fracturing fluid.

[0627] 170. A composite material according to embodiment 167, wherein the turbostratic graphene is a fluid loss prevention additive for the liquid material.

[0628] 171. A composite material according to embodiment 167, wherein the viscosity of the composite material is at least 1 mPa-s greater than the viscosity of the liquid material without the turbostratic graphene.

[0629] 172. A composite material according to embodiment 152, wherein the second material is a dry lubricant.

[0630] 173. A dry lubricant comprising turbostratic graphene.

[0631] 174. A dry lubricant according to embodiment 173, wherein the dry lubricant is the turbostratic graphene.

[0632] 175. A composition of low-defect turbostratic graphene.

[0633] 176. The composition of embodiment 175, wherein:

[0634] (a) the turbostratic graphene comprises a plurality of graphene sheets, and

[0635] (b) The graphene sheet mainly contains sp 2 Hybridized carbon atoms.

[0636] 177. A composition according to embodiment 165, wherein the graphene sheet comprises at least 70 atomic % sp 2 Hybridized carbon atoms.

[0637] 178. A method comprising chemical covalent functionalization of turbostratic graphene, wherein the functionalizing atoms are selected from the group consisting of oxygen, carbon, metals, sulfur, phosphorus, non-metals, metalloids, and combinations thereof.

[0638] 179. A method comprising chemical non-covalent functionalization of turbostratic graphene by one or more of the following: surfactants, DNA, proteins, polymers, aromatic compounds, small organic molecules, gases, groundwater contaminants, biological cells, microorganisms, polychlorinated biphenyls, perchlorates, and borates.

[0639] 180. A method comprising:

[0640] (a) selecting a material comprising turbostratic graphene; and

[0641] (b) Use of the material as a scaling inhibitor or as a corrosion inhibitor.

[0642] 181. A method according to embodiment 180, wherein the material is the turbostratic graphene.

[0643] 182. A sensor device comprising turbostratic graphene, wherein the turbostratic graphene is operable in the sensor device to change an electrical property based on adsorption of an analyte.

[0644] 183. A sensor device according to embodiment 182, wherein the electrical property is selected from mobility, resistance, conductance and combinations thereof.

[0645] 184. A sensor device according to embodiment 182, wherein the analyte is selected from the group consisting of gases, biological agents, neural agents and combinations thereof.

[0646] 185. A device comprising turbostratic graphene, wherein the device is selected from an optical device, an optoelectronic device, and a device operable for field emission of electrons or photons.

[0647] References

[0648] Acerce, M. et al., "Metallic 1T phase MoS2 nanosheets as supercapacitor electrode materials", Nat. Nanotech., 2015, 10, 313 - 318 ("Acerce 2015").

[0649] Advincula, P.A. et al., "Accommodating volume change and imparting thermal conductivity by encapsulation of phase change materials in carbon nanoparticles", J. Mater. Chem. A, 2018, 6, 2461 - 2467 ("Advincula 2018").

[0650] Allen, M.J. et al., "Honeycomb carbon: a review of graphene", Chem. Rev., 2009, 110, 132 - 145 ("Allen 2009").

[0651] Brenner, D.W et al., "A second-generation reactive empirical bond order (REBO) potential energy expression for hydrocarbons", J. Phys.: Condens. Matter, 2002, 14, 783 ("Brenner 2002").

[0652] Cai, M., Thorpe et al., "Methods of graphite exfoliation", J. Mater. Chem., 2012, 22, 24992 - 25002 ("Cai 2012").

[0653] Chang, K. et al., "Targeted Synthesis of 2H-and 1T-Phase MoS2 Monolayers for Catalytic Hydrogen Evolution", Adv. Mater., 2016, 28, 10033 - 10041 ("Chang 2016").

[0654] Eda, G., et al., "Large-area ultrathin films of reduced graphene oxide as a transparent and flexible electronic material", Nat. Nano., 2008, 3, 270 ("Eda 2008").

[0655] Ferrari, A.C. et al., "Raman spectroscopy as a versatile tool for studying the properties of graphene", Nat. Nano., 2013, 8, 235 ("Ferrari 2013").

[0656] Ferrari, A.C., "Raman spectroscopy of graphene and graphite: Disorder, electron-phonon coupling, doping and nonadiabatic effects", Solid State Commun., 2007, 143, 47-57 ("Ferrari 2007").

[0657] Ferrari, A.C. et al., "Raman spectrum of graphene and graphene layers", Phys. Rev. Lett., 2006, 97, 187401 ("Ferrari 2006").

[0658] Garlow, J.A. et al., "Large-area growth of turbostratic graphene on Ni(111) via physical vapor deposition", Scientific reports, 2016, 6, 19804 ("Garlow 2016").

[0659] Gustavsson, J. et al., "Global food losses and food waste", FAO Rome, 2011 ("Gustavsson 2011").

[0660] Han, X. et al., "Laser-Induced Graphene from Wood Impregnated with Metal Salts and Use in Electrocatalysis", ACS Appl. Nano Mater. 2018, 9, 5053-5061 ("Han 2018").

[0661] Hao, Y. et al., "Probing Layer Number and Stacking Order of Few-Layer Graphene by Raman Spectroscopy", Small, 1990, 6(2), 195-200 ("Hao 1990").

[0662] Harris, P.J.F., "Engineering carbon materials with electricity", Carbon, 2017, 122, 504-513 ("Harris 2017").

[0663] Hernandez, Y. et al., "High-yield production of graphene by liquid-phase exfoliation of graphite", Nat. Nano., 2008, 3, 563 ("Hernandez 2008").

[0664] Hosseini, E., et al., "Multifunctional ceramic composites via intercalation of fused graphene-boron nitride nanosheets", ACS App. Mater. Interf., 2019, 11, 8635-8644 ("Hosseini 2019").

[0665] Jambeck, J.R. et al., "Plastic waste inputs from land into the ocean", Science, 2015, 347, 768-771 ("Jambeck 2015").

[0666] Kato, H. et al., “Growth and Raman spectroscopy of thickness-controlled rotationally faulted multilayer graphene”, Carbon, 2019, 141, 76-82 (“Kato 2019”).

[0667] Kim, K. et al., “Raman spectroscopy study of rotated double-layer graphene: misorientation-angle dependence of electronic structure”, Phys. Rev. Lett., 2012, 108, 246103 (“Kim 2012”).

[0668] Kiselov, V. et al., “The growth of weakly coupled graphene sheets from silicon carbide powder”, Semiconductor physics quantum electronics & optoelectronics, 2014, 301-307 (“Kiselov 2014”).

[0669] Kudin, K.N. et al., “Raman spectra of graphite oxide and functionalized graphene sheets”, Nano Lett., 2008, 8, 36-41 (“Kudin 2008”).

[0670] Kumar, N. et al., “High-temperature phase transformation and low friction behaviour in highly disordered turbostratic graphite”, J. Phys. D: Appl. Phys., 2013, 46, 395305 (“Kumar 2013”).

[0671] Li, D. et al., “Processable aqueous dispersions of graphene nanosheets”, Nat. Nano., 2008, 3, 101 (“Li 2008”).

[0672] Li, Z.Q. et al., "X-ray diffraction patterns of graphite and turbostratic carbon", Carbon, 2007, 45, 1686-1695 ("Li 2007").

[0673] Lin, J. et al., "Laser-Induced Porous Graphene Films from Commercial Polymers", Nature Comm. 2014, 5:5714 ("Lin 2014").

[0674] Luong, D.X. et al., "Laser-induced graphene fibers", Carbon, 2018, 126, 472-479 ("Luong 2018").

[0675] Malard, L.M. et al., "Raman spectroscopy in graphene", Phys. Rep., 2009, 473, 51-87 ("Malard 2009").

[0676] Moghaddam, H.E. et al., "Morphogenesis of cement hydrate", J. Mater. Chem. A, 2017, 5, 3798-3811 ("Moghaddam 2017").

[0677] Ni, Z.H. et al "Probing Charged Impurities in Suspended Graphene Using Raman Spectroscopy", ACS Nano, 2009, 3, 569-574 ("Ni 2009").

[0678] Niilisk, A. et al., "Raman characterization of stacking in multi-layer graphene grown on Ni", Carbon, 2016, 98, 658-665 ("Niilisk 2016").

[0679] Novoselov, K.S. et al., "Two-dimensional gas of massless Dirac fermions in graphene", Nature, 2005, 438, 197 ("Novoselov 2005").

[0680] Novoselov, K.S. et al., "Electric Field Effect in Atomically Thin Carbon Films", Science, 2009, 306, 666 - 669 ("Novoselov 2004").

[0681] Parfitt, J., et al., "Food waste within food supply chains: quantification and potential for change to 2050", Philos. Trans. R Soc. Lond. B Biol. Sci., 2010, 365, 3065 - 3081 ("Parfitt 2010").

[0682] Partoens, B. et al., "From graphene to graphite: Electronic structure around the $K$ point", Physical Review B, 2006, 74, 075404 ("Partoens 2006").

[0683] Plimpton, S., "Fast parallel algorithms for short - range molecular dynamics", J. Comput. Phys., 1995, 117, 1 - 19 ("Plimpton 1995").

[0684] Stankovich, S. et al., "Synthesis of graphene - based nanosheets via chemical reduction of exfoliated graphite oxide", Carbon, 2007, 45, 1558 - 1565 ("Stankovich 2007").

[0685] Stuart, S.J., Tutein, A.B., Harrison, J.A. "A reactive potential for hydrocarbons with intermolecular interactions", J. Chem. Phys., 2000, 112, 6472 - 6486 ("Stuart 2000").

[0686] Wang, C. et al., "Hexagonal Boron Nitride - Graphene Core - Shell Arrays Formed by Self - Symmetrical Etching Growth", J. Am. Chem. Soc., 2017, 139, 13997 - 14000 ("Wang 2017").

[0687] Yan, Z. et al., "Hexagonal graphene onion rings", J. Am. Chem. Soc. 2013, 135, 10755 - 10762 ("Yan 2013").

[0688] Yan, Z. et al., "Toward the Synthesis of Wafer - Scale Single - Crystal Graphene on Copper Foils", ACS Nano 2012, 6, 9110 - 9117 ("Yan 2012").

[0689] Yao, Y. et al., "Carbothermal shock synthesis of high - entropy - alloy nanoparticles", Science 359, 1489 - 1494 ("Yao 2018").

[0690] Ye, R. et al., "Laser - Induced Graphene", Acc. Chem. Res. 2018, 51, 1609 - 1620. ("Ye 2018").

[0691] Yi, M. et al., "A review on mechanical exfoliation for the scalable production of graphene", J. Mater. Chem. A, 2015, 3, 11700 - 11715 ("Yi 2015").

[0692] Yu, Y. et al., "High phase-purity 1T'-MoS2-and 1T'-MoSe2-layered crystals", Nat. Chem., 2018, 10, 638-643 ("Yu 2018").

[0693] Zhang, C., et al. "Single-Atomic Ruthenium Catalytic Sites on Nitrogen-DopedGraphene for Oxygen Reduction Reaction in Acidic Medium", ACS Nano 2017, 11, 6930-6941 ("C. Zhang 2017").

[0694] Zhang, J. et al., "In Situ Synthesis of Efficient Water Oxidation Catalysts in Laser-Induced Graphene", ACS Energy Lett. 2018, 3, 677-683 ("J. Zhang 2018").

[0695] Zhang, J. et al., "Efficient Water Splitting Electrodes Based on Laser-Induced Graphene", ACS Appl.Mater.Interfaces 2017, 9, 26840-26847 ("J.Zhang2017").

[0696] U.S. Patent No. 9,449,857, “Process for high yield production of graphene via detonation of carbon-containing material,” issued September 13, 2016, Sorensen et al. (“Sorensen’857 patent”).

[0697] U.S. Patent Application Publication No. 20170062821, published on March 2, 2017, Tour et al. (“Tour’s ’821 patent application”).

[0698] Although embodiments of the present invention have been shown and described, those skilled in the art may modify them without departing from the spirit and teachings of the present invention. The described embodiments and examples provided herein are exemplary only and are not intended to be limiting. Many variations and modifications of the present invention disclosed herein are possible and are within the scope of the present invention. The scope of protection is not limited by the description set forth above, but only by the claims thereafter, the scope of which includes all equivalents of the subject matter of the claims.

[0699] The disclosures of all patents, patent applications, and publications cited herein are hereby incorporated by reference in their entirety, to the extent they provide exemplary, procedural or other details supplementary to those described herein.

[0700] Amount and other numerical data can be proposed in the form of range in the text. It is to be understood that such range form is used only for convenience and simplicity, and should be flexibly interpreted as not only including the numerical value clearly described as the limit of the range, but also including all single numerical values ​​or sub-ranges covered in the range, as if each numerical value and sub-range are clearly described. For example, the numerical range of about 1-about 4.5 should be interpreted as not only including the limit of 1-about 4.5 clearly described, but also including single numbers such as 2,3,4 and sub-ranges such as 1-3,2-4, etc. The same principle applies to the range of describing only one numerical value, such as "less than about 4.5", which should be interpreted as including all the above-mentioned values ​​and ranges. In addition, no matter how the width of the range or the characteristics to be described, such an explanation should be applied. The symbol "~" is the same as "about".

[0701] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the subject matter of the present disclosure belongs. Although any methods, devices, and materials similar or equivalent to those described herein can be used in the practice or testing of the subject matter of the present disclosure, representative methods, devices, and materials are now described.

[0702] Following long-standing patent law convention, the terms "a" and "an" when used in this application, including the claims, mean "one or more."

[0703] Unless otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the presently disclosed subject matter.

[0704] As used herein, the terms "about" and "substantially" when expressing a value or an amount of mass, weight, time, volume, concentration, or percentage, are meant to encompass variations from the stated amount of ±20% in some embodiments, ±10% in some embodiments, ±5% in some embodiments, ±1% in some embodiments, ±0.5% and in some embodiments ±0.1% as such variations are appropriate to perform the disclosed methods.

[0705] As used herein, the terms "substantially perpendicular" and "substantially parallel" are meant to encompass variations within ±10° of perpendicular and parallel directions, respectively, in some embodiments, within ±5° of perpendicular and parallel directions, respectively, in some embodiments, within ±1° of perpendicular and parallel directions, respectively, and in some embodiments, within ±0.5° of perpendicular and parallel directions, respectively.

[0706] As used herein, the term "and / or," when used in the context of listing entities, refers to the entities as being present individually or in combination. Thus, for example, the phrase "A, B, C, and / or D" includes A, B, C, and D individually, and also includes any and all combinations and subcombinations of A, B, C, and D.

Claims

1. A method comprising synthesizing graphene such as turbostratic graphene by applying a voltage pulse across a conductive carbon source that is not substantially graphene, Preferably, - wherein the conductivity of the conductive carbon source is greater than 10 -5 S / cm, or greater than 10 -3 S / cm; - wherein the duration of the voltage pulse is from 1 microsecond to 5 seconds, or from 100 milliseconds to 500 milliseconds; - wherein the voltage pulse is repeated 2 to 100 times, or 2 to 10 times; - Wherein the current across the sample is 0.01A / cm 2 Up to 10000A / cm 2 , or 0.1A / cm 2 Up to 1000A / cm 2 ; - wherein the voltage across the sample is from 10 V / cm to 4000 V / cm, or from 100 V / cm to 400 V / cm; - wherein the conductive carbon source is selected from anthracite, biochar treated at a relatively high temperature, calcined petroleum coke, shungite, carbon nanotubes, asphaltene, acetylene black, carbon black and mixtures thereof; - wherein the conductive carbon source comprises a conductive carbon source additive, the conductive carbon source additive makes the conductive carbon source have sufficient conductivity for use in the method, preferably wherein: (a) the conductive carbon source additive is selected from anthracite, biochar treated at a relatively high temperature, calcined petroleum coke, carbon nanotubes, graphene quantum dots, acetylene black, carbon black, shungite, graphene or a mixture thereof; (b) the conductive carbon source is a relatively low conductivity carbon material selected from the group consisting of feces, plastics, vinyl polymers, condensation polymers, step-growth polymers, chain-growth polymers, activated polymers, rubber, humic acid, carbohydrates, rice flour, food waste, food, coal, organic waste, organic materials, bituminous coal, coke, petroleum coke, petroleum, petroleum products, carbon obtained by removing non-carbon atoms from natural gas or petroleum or carbon dioxide, wood, cellulose, leaves, branches, grass, biomass, animal carcasses, fish carcasses, proteins, and mixtures thereof; and (c) adding the conductive carbon source additive to the lower conductivity carbon material so that the lower conductivity source has sufficient conductivity for use in the method; - wherein prior to said method, said conductive carbon source comprises less than 50% graphene, preferably comprises substantially no spectroscopically detectable graphene; and / or - wherein the product yield of the process comprises at least 70% graphene, preferably at least 90% graphene, more preferably 100% graphene such as turbostratic graphene.

2. The method according to claim 1, wherein the conductive carbon source comprises: (a) The conductivity is at most 10 -7 S / cm of carbon source; and (b) a conductive carbon source additive intermixed with the carbon source, wherein the conductivity of the conductive carbon source is at least 10 -5 S / cm, Preferably, - wherein the conductivity of the conductive carbon source is at least 10 -3 S / cm; and / or - wherein the conductive carbon source additive is selected from carbon black, metal powder and combinations thereof.

3. The method according to claim 1, wherein the conductive carbon source comprises carbon black and rubber, preferably wherein the conductive carbon source comprises 1 wt% to 10 wt% of carbon black or 4 wt% to 6 wt% of carbon black.

4. The method according to claim 1, wherein the step of applying a voltage pulse uses a DC voltage, or the method of applying a voltage pulse uses an AC voltage, or the voltage pulse is applied using a power supply using a three-phase electric power.

5. A method comprising synthesizing graphene by applying a voltage pulse across a conductive carbon source that is not substantially graphene, wherein when the voltage pulse is applied across the conductive carbon source, heteroatoms are present to provide a doped or heteroatom-containing graphene product, Preferably, the heteroatom is selected from nitrogen, phosphorus, boron and mixtures thereof, or the heteroatom is selected from metals, semi-metals and mixtures thereof, or the heteroatom source is selected from melamine, aminoborane, melamine-formaldehyde resin, phosphine, phosphate, metal salt, metal oxide and mixtures thereof.

6. A device comprising: (a) a carbon feedstock comprising a conductive carbon source that is substantially not graphene; (b) a non-conductive container operable to confine the conductive carbon source; and (c) an electrode operable to apply a voltage pulse across the conductive carbon source within the non-conductive container to synthesize graphene, Preferably, - wherein the apparatus further comprises a conduit through which the electrically conductive carbon source can be transported to the non-conductive container; - wherein the apparatus further comprises a chamber in which the non-conductive container can be located when the electrode applies a voltage pulse; - wherein the non-conductive container comprises quartz or ceramic material, for example, the non-conductive container comprises a quartz tube; -in: (a) the device comprises a plurality of the non-conductive containers; and (b) the apparatus further comprises a belt or screw and a collection box; and (c) the belt or screw is operable to: (i) after the conductive carbon source is filled in the non-conductive container, transferring the container among the plurality of the non-conductive containers into the chamber; and (ii) transporting the non-conductive container out of the chamber to a location where the synthesized graphene can be collected in the collection box; - wherein said device comprises a plurality of capacitors operable to apply said voltage pulses; - wherein the device comprises a controller and a mechanical relay operable to control the application of the voltage pulses, preferably wherein the device comprises an inductor and a diode operatively connected to the controller and the mechanical relay; - wherein said device further comprises a cut-off switch; - wherein the conductive carbon source comprises a conductivity of at least 10 -5 S / cm if at least 10 -3 S / cm of carbon source; - wherein the conductive carbon source comprises a carbon source and a conductive carbon source additive such as carbon powder, preferably wherein: (a) the electrical conductivity of the carbon source is at least at most 10 -6 S / cm; and (b) the electrical conductivity of the conductive carbon source is at least 10 -5 S / cm, for example at least 10 -3 S / cm.

7. A system comprising the device according to claim 6, Preferably, - wherein the device is operatively connected to a DC voltage source, or wherein the device is operatively connected to an AC voltage source, or wherein the device is operatively connected to a power supply using three-phase electric power, optionally followed by full-wave rectification.

8. A method of forming a 2D material, wherein the method comprises: (a) selecting a precursor material comprising a precursor; (b) applying a voltage pulse across the material to form the 2D material, Preferably, - wherein the conductivity of the precursor is greater than 10 -6 S / cm, preferably the precursor comprises a metal source, for example a metal source selected from iron powder, molybdenum powder, tungsten metal and copper metal, or wherein the precursor comprises a non-metallic source, for example, a non-metallic source selected from carbon black, calcined petroleum coke; -in: (a) The electrical conductivity of the precursor is less than 10 -6 S / cm, for example less than 10 -7 S / cm; (b) the precursor material further comprises a conductive source; and (c) The electrical conductivity of the precursor material is greater than 10 -5 S / cm. - wherein the precursor is selected from molybdenum disulfide (MoS2), ammonium tetrathiomolybdate ((NH4)2MoS4), borane ammonia complex (BH3NH3), red phosphorus and combinations thereof. - wherein the conductive source is selected from carbon materials, metal powders and combinations thereof.

9. An apparatus comprising: (a) a precursor material comprising a precursor; (b) a non-conductive container operable to confine the precursor material; and (c) an electrode operable to apply a voltage pulse across the precursor material within the non-conductive container to produce a 2D material, Preferably, - wherein the apparatus further comprises a conduit through which the precursor can be transported to the non-conductive container; - wherein the apparatus further comprises a chamber, wherein the non-conductive container is positionable within the chamber when the electrode applies a voltage pulse; - wherein the non-conductive container comprises quartz or ceramic material; -in: (a) the device comprises a plurality of the non-conductive containers; (b) the apparatus further comprises a belt or screw and a collection box; and (c) the belt or screw is operable to: (i) after the precursor material is filled in the non-conductive container, transporting the non-conductive container among the plurality of non-conductive containers into the chamber; and (ii) transporting the non-conductive container out of the chamber to a location where the prepared 2D material can be collected in the collection box; - wherein the device comprises a plurality of capacitors operable to apply voltage pulses; - wherein the apparatus comprises a controller and a mechanical relay operable to control the application of the voltage pulses; - wherein the device comprises an inductor and a diode operatively connected to a controller and a mechanical relay; - wherein the device further comprises a cut-off switch. - wherein the conductivity of the precursor is at least 10 -5 S / cm, for example at least 10 -3 S / cm; - wherein the precursor material further comprises a conductive source.

10. A system comprising the device according to claim 9.

11. A method comprising synthesizing a large batch of turbostratic graphene, Preferably, - wherein the method comprises a flash graphene process to produce turbostratic graphene from a carbon-based material; - wherein the turbostratic graphene is low-defect turbostratic graphene; - It further comprises making a composite material using the turbostratic graphene.

12. A method comprising: (a) selecting a material comprising turbostratic graphene; and (b) Use of the material as a scaling inhibitor or as a corrosion inhibitor.

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