Flash-within-flash Joule heating method and system

Abstract

A method and system for flash-within-flash (FWF) Joule heating. The FWF Joule heating process involves subjecting an outer raw material in an outer container to a flash Joule heating process, thereby causing the flash Joule heating process on the outer raw material to result in the conversion of the inner raw material in an inner container (which is located within the outer container) to a conversion material.

Description

Related Application

[0001] Cross-reference of related applications This application claims priority to U.S. Provisional Patent Application No. 63 / 520,553 filed on August 18, 2023, entitled "Methods Of Flash-Within-Flash Joule Heating And Compositions Thereof", in the name of James Mitchell Tour, et al., which application is commonly owned by the assignee of the present invention and is incorporated herein by reference in its entirety. Technical Field

[0002] The present invention relates generally to methods and systems for flash Joule heating (FJH), including specifically methods and systems for flash-within-flash Joule heating.

[0003] Government involvement This invention was made with government support under Grant No. FA9550-22-1-0526 awarded by the United States Air Force Office of Scientific Research, and Grant Nos. ERDC W912HZ-21-2-0050 and W912HZ-24-2-0027 awarded by the United States Engineer Research and Development Center for the United States Army Corp of Engineers. The United States Government has certain rights in the invention. Background Art

[0004] Next-generation synthesis protocols must meet three key criteria for minimizing environmental impact: reduced solvent and water usage, improved energy efficiency, and scalability. [Raabe 2023; Aykol 2021]. Many synthesis processes require high temperatures (>600°C) or long reaction times ranging from several hours to several days, making it often difficult to achieve these requirements using thermodynamic equilibrium. Recent non-equilibrium synthesis using rapid thermal shock via ultrafast resistance Joule heating has emerged as a more promising method for producing specific products, including ceramics [Wang C 2022; Deng II 2022], metastable materials [Zheng 2023; Chen II 2021], as well as value-added chemicals and materials [Luong 2020; Deng I 2022; Wyss 2022; Wyss 2023; Yao 2018; Chen 2016]. These established methods are carried out in milliseconds to minutes, thereby demonstrating a significant reduction in energy consumption. However, these protocols often need to meet specific electrical conductivity requirements, thereby limiting the reagents that can be used. To circumvent this limitation, the introduction of conductive additives or substrates is necessary, which introduces impurities and makes it difficult to obtain the single product. Furthermore, the incorporation of volatile reagents such as chalcogens (e.g., S and Se) is difficult to achieve due to the intense heat caused by resistance heating, thus limiting the incorporation of these elements.

[0005] Due to limitations in FJH, it is difficult to produce amorphous carbon as the main product (<90%) from various carbon-based raw materials, including municipal solid waste. Unlike turbid graphene, amorphous carbon does not exhibit crystalline properties and is used everywhere in air and water filters, cosmetics, inks, and composite materials. The classification of amorphous carbon includes materials such as (activated) charcoal, activated carbon, biochar, and combinations and mixtures thereof. Because FJH converts these carbon-based raw materials into turbid graphene during the reaction, it is difficult to obtain amorphous carbon materials and derivatives (e.g., heteroatom-doped amorphous carbon).

[0006] Therefore, conventional flash Joule heating (FJH) is generally not suitable for producing inorganic compounds. Instead, inorganic compounds are generally produced by methods such as chemical vapor deposition, flux growth, arc melting, and hydrothermal synthesis. These methods typically involve trade-offs between crystal quality, synthesis rate, and scalability. For example, chemical vapor deposition can produce high-quality crystalline materials, but doing so on a gram-scale or higher within an hour is extremely difficult. Similarly, flux growth can produce high-quality gram-scale inorganic crystals, but for many compounds, synthesis times range from several hours to several weeks. Conventional flash Joule heating has been demonstrated to perform multi-gram-scale reactions in seconds with high crystal quality, but so far, the types of inorganic compounds that can be used to produce have been significantly limited due to carbide formation, carbon contamination, and unsuitable resistivity. [Overview of the Initiative]

[0007] The present invention relates in particular to a flash-within-flash-joule heating (FWF) method and system, the flash-joule heating method and system.

[0008] In general, in one embodiment, the present invention is characterized by a method comprising providing an inner raw material in an inner container. The method further comprises providing an outer raw material in an outer container. The inner container is located in an outer container within a flash Joule heating apparatus. The method further comprises applying one or more voltage pulses, alternating current (AC), direct current (DC), or a combination thereof to the entire outer raw material to subject the outer raw material to a flash Joule heating process, thereby causing the flash Joule heating process on the outer raw material to result in the conversion of the inner raw material to a conversion material.

[0009] The implementation of the present invention may include one or more of the following features.

[0010] This method can be carried out in a continuous process in which voltage is supplied to the outer raw material that is flash-heated by Joule.

[0011] A flash Joule heating process for the outer raw material can provide conductive and / or radiant heating to the inner raw material, resulting in the conversion of the inner raw material into a conversion material.

[0012] A flash Joule heating process for the outer raw material can provide conductive heating to the inner raw material, resulting in the conversion of the inner raw material into a conversion material.

[0013] A flash Joule heating process for the outer raw material can provide radiant heating to the inner raw material, resulting in the conversion of the inner raw material into a conversion material.

[0014] A flash Joule heating process for the outer raw material can provide both conductive and radiant heating to the inner raw material, resulting in the conversion of the inner raw material into a conversion material.

[0015] The conversion material can be a three-dimensional material.

[0016] The conversion material can be a two-dimensional material.

[0017] The conversion material can be a one-dimensional material.

[0018] The conversion material can be an amorphous material.

[0019] The conversion materials are FeS2, CoS2, and CoS x Se y , CoSe, NiS2, NiSe2, Cu9S5, NbSe2, MoSe2, TiSe2, In2Se3, SnS2, SnS x Se y , SnSe2, WSe2, WS2, Bi2S3, Bi x S y Se z, Bi2Se3, TiN, LaBO3, Cu2Se, Cu 0.87 You can choose from the group consisting of Se, as well as combinations and mixtures thereof.

[0020] The conversion material may include chalcogenides, metals, and / or alloys.

[0021] Metals can be extracted from ores and minerals using reactors.

[0022] Using a reactor, metals can be extracted from electronic waste sources.

[0023] The conversion material may include amorphous carbon and its derivatives.

[0024] The outer raw material can be selected from the group consisting of graphene, flash graphene, randomly layered graphene, anthracite, coconut shell-derived carbon, high-temperature treated biochar, activated charcoal, calcined petroleum coke, metallurgical coke, coke, shungite, carbon nanotubes, asphaltene, acetylene black, carbon black, ash, carbon fiber, graphite, and combinations and mixtures thereof.

[0025] The outer material can be converted to flash graphene after applying a voltage pulse to the entire outer material and subjecting it to a flash Joule heating process.

[0026] Flash graphene can be reused multiple times as an outer raw material using the method described above.

[0027] The method may further include removing the conversion material from the inner container. The method may further include providing a second inner material into the inner container. The method may further include applying one or more voltage pulses, alternating current (AC), direct current (DC), or a combination thereof across the flash graphene in the outer container to subject the flash graphene to a flash Joule heating process, thereby causing the flash Joule heating process on the flash graphene to result in the conversion of the second inner material into a second conversion material.

[0028] The second internal raw material can be the same type of raw material as the internal raw material converted into the conversion material. The second conversion material can be the same type as the conversion material.

[0029] The second internal raw material can be a different type of raw material from the internal raw material converted into the conversion material. The second conversion material can be a different type from the conversion material.

[0030] The step of applying one or more voltage pulses can utilize DC voltage.

[0031] The step of applying one or more voltage pulses can utilize pulsed DC.

[0032] The step of applying one or more voltage pulses can utilize AC voltage.

[0033] The step of applying one or more voltage pulses can utilize a combination of DC and AC voltages.

[0034] The step of applying one or more voltage pulses, AC, DC, or a combination thereof may include controlling the flash Joule heating process through controlled electronic modulation. Controlled electronic modulation can occur through control selected from the group consisting of variable frequency drive (VFD), pulse width modulation (PWM), proportional-integral-derivative (PID) control, ternary control, and combinations thereof.

[0035] Controlled electronic modulation can utilize (i) DC current, (ii) uniform non-progressing AC current, or (iii) a combination thereof.

[0036] This method may further include applying an inner container current through the inner material when one or more voltage pulses, AC, DC, or combinations thereof are applied to the entire outer material.

[0037] The application of current through the inner material can be independently controlled when applying one or more voltage pulses, AC, DC, or a combination thereof to the entire outer material.

[0038] A separate tube can be fabricated using cylindrically wound graphite foil, which can be used as a heating element outside the inner quartz tube.

[0039] Graphite tubes can be used as both heating tubes and raw material holding tubes.

[0040] A gap or physical separation exists between the graphite tube and the inner tube, which suppresses conductive heating of the inner tube and promotes radiation as the primary heating mechanism.

[0041] The entire system can be enclosed in a quartz tube.

[0042] An inert gas can flow through this gap, allowing heating by convection, conduction, and / or a combination thereof.

[0043] Reactive gases can be introduced into the chamber along with the raw materials to assist in chemical synthesis or decomposition.

[0044] The reactive gas can be chlorine gas.

[0045] Reactive gases can be introduced into the chamber along with the raw materials to assist in the chemical synthesis or decomposition of the ore.

[0046] The individual tubes can be reused multiple times.

[0047] The separate tubes can be made of graphite. (Graphite becomes stable when electrically heated, so it can be reused multiple times.)

[0048] This system can be arranged in a concentric pattern, alternating between the heating tubes and the raw material holding tubes.

[0049] The tube may have a cylindrical shape.

[0050] The pipe may have a non-cylindrical shape.

[0051] Non-cylindrical shapes can be half-cylindrical.

[0052] In general, in another embodiment, the present invention features an apparatus comprising an inner container operable to receive an inner raw material. The apparatus further comprises an outer container operable to receive an outer raw material. The outer container is a non-conductive container operable to confine the outer raw material, or a conductive container operable to be directly flash-joule heated. The apparatus further comprises electrodes operable to apply voltage pulses, AC, DC, or a combination thereof to the entire outer raw material confined within the outer container, thereby subjecting the outer raw material to a flash-joule heating process, the flash-joule heating process to the outer raw material resulting in the conversion of the inner raw material to a conversion material.

[0053] Embodiments of the present invention can include one or more of the following features.

[0054] The outer container may be a non-conductive container operable to confine the outer raw material.

[0055] The outer container may be an electrically conductive container operable to be directly subjected to flash Joule heating.

[0056] The apparatus is operable to perform a continuous process in which a voltage is supplied to an outer raw material that is subjected to flash Joule heating.

[0057] The conversion material may be a three-dimensional material.

[0058] The conversion material may be a two-dimensional material.

[0059] The conversion material may be a one-dimensional material.

[0060] The conversion material may be an amorphous material.

[0061] The conversion material may be selected from the group consisting of FeS2, CoS2, CoS x Se y , CoSe, NiS2, NiSe2, Cu9S5, NbSe2, MoSe2, TiSe2, In2Se3, SnS2, SnS x Se y , SnSe2, WSe2, WS2, Bi2S3, Bi x S y Se z , Bi2Se3, TiN, LaBO3, Cu2Se, Cu 0.87 Se, and combinations and mixtures thereof.

[0062] The conversion material may comprise chalcogenides, metals, and / or alloys.

[0063] The reactor can be used to extract metals from ores and minerals.

[0064] Using a reactor, metals can be extracted from electronic waste sources.

[0065] The outer raw material can be selected from the group consisting of graphene, flash graphene, randomly layered graphene, anthracite, coconut shell-derived carbon, high-temperature treated biochar, activated charcoal, calcined petroleum coke, metallurgical coke, coke, shungite, carbon nanotubes, asphaltene, acetylene black, carbon black, ash, carbon fiber, graphite, and combinations and mixtures thereof.

[0066] The outer material can be converted to flash graphene after being subjected to a flash Joule heating process by applying voltage pulses, AC, DC, or a combination thereof to the entire outer material.

[0067] The outer material is not graphite.

[0068] The electrodes can be connected to a DC voltage source.

[0069] The electrodes can be connected to a pulsed DC source.

[0070] The electrodes can be connected to an AC voltage source.

[0071] The electrodes can be connected to DC and AC voltage sources.

[0072] The apparatus may further include a controller that controls the flash Joule heating process applied by the electrodes through controlled electronic modulation. The controller can be selected from a group consisting of variable frequency drive (VFD) controllers, pulse width modulation (PWM) controllers, proportional-integral-derivative (PID) control controllers, ternary control controllers, and combinations thereof.

[0073] Controlled electronic modulation can operate by utilizing (i) a DC current, (ii) a uniform non-progressing AC current, or (iii) a combination thereof.

[0074] The apparatus may further include an inner container electrode that is operable to apply an inner container current through the inner material when one or more voltage pulses, AC, DC, or combinations thereof are applied to the entire outer material.

[0075] The inner container electrodes are operable to be independently controlled when one or more voltage pulses, AC, DC, or combinations thereof are applied to the entire outer material.

[0076] The apparatus may further include a controller that independently controls the application of current through the inner material when one or more voltage pulses, AC, DC, or combinations thereof are applied to the entire outer material.

[0077] A separate tube can be fabricated using cylindrically wound graphite foil, which can be used as a heating element outside the inner quartz tube.

[0078] Graphite tubes can be used as both heating tubes and raw material holding tubes.

[0079] A gap or physical separation exists between the graphite tube and the inner tube, which can suppress conductive heating of the inner tube and promote radiation as the primary heating mechanism.

[0080] The entire system can be enclosed in a quartz tube.

[0081] An inert gas can flow through this gap, allowing heating by convection, conduction, and / or a combination thereof.

[0082] Reactive gases can be introduced into the chamber along with the raw materials to assist in chemical synthesis or decomposition.

[0083] The reactive gas can be chlorine gas.

[0084] Reactive gases can be introduced into the chamber along with the raw materials to assist in the chemical synthesis or decomposition of the ore.

[0085] The individual tubes can be reused multiple times.

[0086] The separate tubes can be made of graphite.

[0087] This system can be arranged in a concentric pattern, alternating between the heating tubes and the raw material holding tubes.

[0088] The tube may have a cylindrical shape.

[0089] The pipe may have a non-cylindrical shape.

[0090] The non-cylindrical shape can be a semi-cylindrical tube.

[0091] Graphite foil can be clamped to a copper or brass tube to provide electrical contact while offering access for inserting a quartz tube that holds the material to be flash-heated.

[0092] A graphite cylinder can be used. The graphite cylinder may have a section that is heated with a reduced outer diameter or an increased length in order to increase resistance within the section.

[0093] The support rods connect to the clamps, maintaining structural rigidity and minimizing strain on the graphite heating element.

[0094] A quartz cylinder or rod can be used to define the distance between clamps, which can withstand heat and do not undergo thermal expansion when heated, thus reducing strain on the graphite foil cylinder.

[0095] Metal rods and springs can be used as tensioning elements, mounted within insulating sleeves to prevent electrical conduction between clamps.

[0096] The assembly can be purged with an inert gas or sealed in an outer cylinder that is vacuumed to prevent oxidation of electrically heated graphite tubes.

[0097] The outer cylinder can be made of quartz or borosilicate tubing.

[0098] The outer cylinder can be a metal tube that can be pressurized.

[0099] By positioning a radiation shield around a tubular graphite heater, the radiation it would otherwise emit is reflected off the heater element, thereby reducing the electrical energy required to maintain the temperature.

[0100] Radiation shielding may include one or more of the following materials: copper, nickel, molybdenum, and aluminum.

[0101] Gold coating can be used to improve reflectivity.

[0102] The end cap can be PTFE, or other insulating material that holds and seals the copper or brass tube.

[0103] Water cooling can be added to copper or brass tubing.

[0104] Heat from a graphite tube can be transferred through small gaps by radiation, convection, and conduction, in the presence of an inert gas.

[0105] The enclosure can be vacuumed, and heat transfer to the inner quartz tube occurs by radiation.

[0106] A small opening or slot can be created inside the graphite tube to provide an observation port for the inner quartz tube and the sample.

[0107] To allow for the independent application of external heating and electric fields, there should be no electrical connection between the graphite tube and the material inside the quartz tube.

[0108] In general, in another embodiment, the present invention features an apparatus comprising an inner container operable for receiving raw materials. The apparatus further comprises an outer container operable to provide a protective atmosphere or vacuum to a resistance heater. The apparatus further comprises a resistance heater within the outer container. The apparatus further comprises electrodes operable to provide AC or DC current to the resistance heater. The apparatus further comprises a plug within the inner container for containing raw materials internally.

[0109] The implementation of the present invention may include one or more of the following features.

[0110] The inner container can be a transparent inner container. The resistance heater can be a tubular resistance heater. The resistance heater can be concentric within the outer container. The electrodes can be tubular electrodes.

[0111] The inner container can be a quartz glass tube.

[0112] The inner container can be a transparent quartz glass tube.

[0113] A resistance heater can be a cylindrical roll of graphite foil.

[0114] A resistance heater can be a graphite tube.

[0115] A resistance heater can be a graphite tube that is thinned in the middle.

[0116] The outer container can be a quartz glass tube.

[0117] The outer container can be a quartz glass tube surrounded by a PTFE end cap and an O-ring seal.

[0118] The outer container can be a metal tube.

[0119] The outer container can be a metal tube that is movable to withstand pressure.

[0120] The electrodes may include metals selected from the group consisting of copper, brass, nickel, and combinations thereof.

[0121] The electrodes can be selected from the group consisting of copper electrodes, brass electrodes, nickel electrodes, and combinations thereof.

[0122] The apparatus may further include graphite foil clamped to the electrodes.

[0123] The apparatus may further include a rigid support structure for a tube or rod that minimizes strain on the resistance heater.

[0124] The tube or rod may be a quartz tube or rod.

[0125] The resistance heater may include graphite foil.

[0126] A resistance heater can be a graphite tube.

[0127] A resistance heater can be electrically heated by applying one or more voltage pulses, alternating current (AC), direct current (DC), or a combination thereof.

[0128] One or more applied voltage pulses, alternating current (AC), direct current (DC), or a combination thereof can provide radiant heat transfer to the raw materials within the inner container.

[0129] The plug inside the inner container can be conductive.

[0130] The plug inside the inner container can be connected to a high-voltage power supply.

[0131] The plug inside the inner container can be connected to a high-voltage power supply by a wire.

[0132] The plug inside the inner tube can be porous.

[0133] The plug inside the inner tube can be porous to allow gas to enter or exit.

[0134] The device is operable for one or more voltage pulses, alternating current (AC), direct current (DC), or a combination thereof, applied to the raw material in the inner container. [Brief explanation of the drawing]

[0135] [Figure 1A] Embodiments of the present invention illustrate a flash-within-flash (FWF) Joule system protocol operating in thermal conduction mode. A schematic diagram of FWF (Type 1) is shown. [Figure 1B] Embodiments of the present invention illustrate a flash-within-flash (FWF) Joule system protocol operating in thermal conduction mode. The current and temperature profiles of a 340V FWF reaction are shown. [Figure 1C] Embodiments of the present invention illustrate a flash-within-flash (FWF) Joule system protocol operating in thermal conduction mode. A schematic diagram of a multiple FWF reaction (Type 2) is shown to allow for further (and potentially complete) conversion of the unreacted precursor. [Figure 1D]Embodiments of the present invention illustrate a flash-within-flash (FWF) Joule system protocol operating in thermal conduction mode. A schematic diagram of an anion exchange FWF reaction (Type 3) is shown to avoid unexpected (and / or undesirable) side reactions. Internal_tube_temperature_and_reaction_dFig._1_FWF._bookmark0 Internal_tube_temperature_and_reaction_dFig._1_FWF._bookmark0 [Figure 2] This shows a circuit diagram of a capacitor bank discharge system that can be used in the FWF process. [Figure 3A] This document describes a FWF system protocol operating in radiant heating mode. It also shows a scheme representing the graphite tube heater, longitudinal section, and tube support of the device enabling radiant FWF heating. [Figure 3B] The FWF system protocol operating in radiant heating mode is shown. Figure 3A shows a scheme of the graphite tube heater, longitudinal section, and cross-sectional view of the tube support. [Figure 3C] This document describes a FWF system protocol operating in radiant heating mode. It also shows a scheme representing graphite tube heaters, longitudinal sections, and tube supports—further devices enabling radiant FWF heating. [Figure 3D] This shows the FWF system protocol operating in radiant heating mode. Figure 3D shows a scheme of the graphite tube heater, longitudinal section, and cross-sectional view of the tube support. [Figure 3E] This shows the FWF system protocol operating in radiant heating mode. A scheme representing the graphite tubular heater in Figure 3C, with independent electric fields / currents, is shown. [Figure 3F] This document describes the FWF system protocol operating in radiant heating mode. It also shows a scheme for rigid graphite tubes that can be used in the embodiment. [Figure 4]A scheme of an embodiment of FWF is shown, demonstrating that the FWF reaction can be conceptually divided between the inner and outer tubes. FWF_reaction_types_Gram_scalability_and_life_cycle_analysisFig._2_Gram_scalability_and_LCA.Extended_Data_Fig._1_Internal_tube_tempeFWF_reaction_types_Gram_scalability_and_life_cycle_analysisFig._2_Gram_scalability_and_LCA.Extended_Data_Fig._1_Internal_tube_tempe [Figure 5A] This shows the internal tube temperature measurement for FWF. It is a schematic diagram of temperature measurement for a normal FWF reaction. [Figure 5B] This shows the measurement of the internal tube temperature for FWF. It is a schematic diagram of the temperature measurement of a distorted internal tube to determine the internal temperature during the reaction. [Figure 5C] This shows the measurement of the inner tube temperature for FWF. It demonstrates that an infrared thermometer with an alignment laser was focused on the sample area to read the time-dependent temperature change during the FWF reaction. [Figure 5D] This shows the internal tube temperature measurement for FWF. It also shows the reaction kinetics during the FWF reaction. [Figure 5E] This shows the internal tube temperature measurement for FWF. It also shows the reaction kinetics during the FWF reaction. [Figure 5F] This shows the internal tube temperature measurement for FWF. It also shows the reaction kinetics during the FWF reaction. [Figure 6A] This demonstrates the gram scalability of FWF. The image shows 1.11 g of WSe2 powder in an analytical balance obtained from a gram-scale reaction. Scale bar, 10 cm. [Figure 6B] This demonstrates the Gram scalability of FWF. The XRD spectrum of WSe2 prepared through a Gram-scale reaction is shown. A reference spectrum is also provided in Figure 6B (below). [Figure 6C]This shows the gram scalability of FWF. It is the Se 3d XPS spectrum of WSe2 powder prepared through a gram-scale reaction. [Figure 6D] This shows the gram scalability of FWF. It is a W 4f XPS spectrum of WSe2 powder prepared through a gram-scale reaction. [Figure 7A] This section describes a variety of reactions and products from FWF. It lists representative elements used in FWF reactions. Smaller subsets show the corresponding anionic components used to produce inorganic compounds. [Figure 7B] This document describes a variety of reactions and products from FWF. It lists all final products with respect to the initial flushing voltage and corresponding energy input. Unless otherwise specified, all synthesis uses type 1 reactions in FWF. [Figure 7C] This shows a variety of reactions and products from FWF. ADF-STEM images and EDX mappings of (C) SnS2, (D) SnSe2, and (E) Se-doped SnS2 (shown as SnSxSey) are shown to demonstrate reagent-dependent moduloability and doping (substitution) capabilities. [Figure 7D] This shows a variety of reactions and products from FWF. ADF-STEM images and EDX mappings of (C) SnS2, (D) SnSe2, and (E) Se-doped SnS2 (shown as SnSxSey) are shown to demonstrate reagent-dependent moduloability and doping (substitution) capabilities. [Figure 7E] This shows a variety of reactions and products from FWF. ADF-STEM images and EDX mappings of (C) SnS2, (D) SnSe2, and (E) Se-doped SnS2 (shown as SnSxSey) are shown to demonstrate reagent-dependent moduloability and doping (substitution) capabilities. [Figure 7F] This shows a variety of reactions and products from FWF. These are ADF-STEM images and EDX mappings of the semiconductor materials (F)MoSe2 (n-type), (G)WSe2 (p-type), and (H)α-In2Se3 (n-type, ferroelectric). [Figure 7G]This shows a variety of reactions and products from FWF. These are ADF-STEM images and EDX mappings of the semiconductor materials (F)MoSe2 (n-type), (G)WSe2 (p-type), and (H)α-In2Se3 (n-type, ferroelectric). [Figure 7H] This shows a variety of reactions and products from FWF. These are ADF-STEM images and EDX mappings of the semiconductor materials (F)MoSe2 (n-type), (G)WSe2 (p-type), and (H)α-In2Se3 (n-type, ferroelectric). [Figure 8A] The selected-field electron diffraction (SAED) patterns of SnS2, α-In2Se3, MoSe2, and WSe2 flakes are shown. The SAED for SnS2 is shown. [Figure 8B] The selected-field electron diffraction (SAED) patterns of SnS2, α-In2Se3, MoSe2, and WSe2 flakes are shown. The SAED for α-In2Se3 is shown. [Figure 8C] The selected-field electron diffraction (SAED) patterns of SnS2, α-In2Se3, MoSe2, and WSe2 flakes are shown. The SAED for MoSe2 is shown. [Figure 8D] The selected-field electron diffraction (SAED) patterns of SnS2, α-In2Se3, MoSe2, and WSe2 flakes are shown. The SAED for WSe2 is shown. All materials exhibited single-crystal properties in each flake. [Figure 9A] XRD and Raman spectra of doping capacity in Sn-based TMDs are shown. XRD spectra of SnS2, Se-doped SnS2 (shown as SnSxSey), and SnSe2 are shown. [Figure 9B] XRD and Raman spectra of doping capabilities in Sn-based TMDs are shown. Raman spectra of SnS2, Se-doped SnS2 (shown as SnSxSey), and SnSe2 are shown, with a subset of corresponding powder photographs. [Figure 10A]This section describes the characterization of the electrical properties of the FWF product. A schematic diagram of the experimental FET device's geometry is shown. Schematic diagrams of the crystal structures of MoSe2, WSe2, and α-In2Se3 are shown within dashed boxes. [Figure 10B] This section describes the characterization of the electrical properties of FWF products. Cross-sectional ADF-STEM images of MoSe2, WSe2, and α-In2Se3 in each of these FET devices are shown. [Figure 10C] This section describes the characterization of the electrical properties of FWF products. Representative transfer curves (gate voltage (VG)-drain current (ID) characteristics under constant drain voltage (VD)) are shown for n-type MoSe2, p-type WSe2, and ferroelectric α-In2Se3 under different VDs (VD = 0.1V and 1V, respectively). The inset shows optical images of the FET devices. Scale bar, 10 μm. [Figure 10D] This section describes the characterization of the electrical properties of FWF products. Representative transfer curves (gate voltage (VG)-drain current (ID) characteristics under constant drain voltage (VD)) are shown for n-type MoSe2, p-type WSe2, and ferroelectric α-In2Se3 under different VDs (VD = 0.1V and 1V, respectively). The inset shows optical images of the FET devices. Scale bar, 10 μm. [Figure 10E] This section describes the characterization of the electrical properties of FWF products. Representative transfer curves (gate voltage (VG)-drain current (ID) characteristics under constant drain voltage (VD)) are shown for n-type MoSe2, p-type WSe2, and ferroelectric α-In2Se3 under different VDs (VD = 0.1V and 1V, respectively). The inset shows optical images of the FET devices. Scale bar, 10 μm. [Figure 10F] This section describes the characterization of the electrical properties of FWF products. Representative output curves (VD~ID characteristics under constant VG) are shown for n-type MoSe2FET devices and p-type WSe2FET devices, respectively, with VG = -40V to VG = 40V. [Figure 10G]This section describes the characterization of the electrical properties of FWF products. Representative output curves (VD~ID characteristics under constant VG) are shown for n-type MoSe2FET devices and p-type WSe2FET devices, respectively, with VG = -40V to VG = 40V. [Figure 10H] This shows the characterization of the electrical properties of FWF products. It also shows the durability characteristics of a ferroelectric In2Se3FET device over 1,000 cycles. The operating voltages are VG=-40V (for SET) and VG=40V (for RESET), and the readout voltage is VD=1V. [Extended_Data_Fig._3_Selected_area_electCharacterization_and_electrical_propertiFig._4_Electrical_properties_characterizTribology_and_coefficient_of_friction_coFig._5_Comparative_analysis_of_tribologi] [Figure 11A] This document presents a comparative analysis of tribological performance. It shows the time-dependent change in the coefficient of friction (COF) for 120,000 measurements of reference alumina, commercial MoSe2, and FWF MoSe2. Simultaneously, moving average trend lines for reference alumina, commercial MoSe2, and FWF MoSe2 under 1N are shown. [Figure 11B] This document presents a comparative analysis of tribological performance. It shows the force-dependent COF changes for reference alumina, commercial MoSe2, and FWF MoSe2. (Extended_Data_Fig._4_S / TEM_images_and_SA) [Figure 12A]These are S / TEM images and SAED patterns for commercial (A-C)MoSe2 and (D-F)FWF MoSe2. The TEM image shows commercial MoSe2 with an amorphous layer of approximately 20 nm at the edges of the flakes. [Figure 12B] These are S / TEM images and SAED patterns for commercial (A-C)MoSe2 and (D-F)FWF MoSe2. Another TEM image of a commercial MoSe2 region with an amorphous layer of approximately 10 nm at the edges of the flake is shown. [Figure 12C] These are S / TEM images and SAED patterns for commercial (A-C)MoSe2 and (D-F)FWF MoSe2. SAED patterns of commercial MoSe2 exhibiting polycrystalline and amorphous components are shown. [Figure 12D] These are S / TEM images and SAED patterns for commercial (A-C)MoSe2 and (D-F)FWF MoSe2. TEM images of FWF MoSe2 with little to no amorphous layer at the edges of the flakes are shown. [Figure 12E] These are S / TEM images and SAED patterns for commercial (A-C)MoSe2 and (D-F)FWF MoSe2. ADF-STEM atomic-resolution images of MoSe2 showing sharp, distinct crystal structures at the edges of the flakes are also shown. [Figure 12F] These are S / TEM images and SAED patterns for commercial (A-C)MoSe2 and (D-F)FWF MoSe2. The SAED pattern for FWF MoSe2 is shown. [Figure 13A] This document presents a comprehensive lifecycle assessment of the FWF (Forward Flux) and a cumulative energy demand analysis. [Figure 13B] This document presents a comprehensive life cycle assessment of the FWF (Forward Flux) and an analysis of its global warming potential. [Figure 13C]This document presents a comprehensive life cycle assessment of FWF. It shows (C) cumulative water usage analysis and (D) estimated product cost (technological and economic analysis) of FWF compared to autoclaving (Mg-assisted) and CVT synthesis to produce 100g of MoSe2, respectively. CO2e, CO equivalent Product_summary_and_doping / substitution_Fig._3_Diverse_reactions_and_products_frProduct_summary_and_doping / substitution_Fig._3_Diverse_reactions_and_products_fr. [Figure 13D] This document presents a comprehensive life cycle assessment of FWF. It shows (C) cumulative water usage analysis and (D) estimated product cost (technological and economic analysis) of FWF compared to autoclaving (Mg-assisted) and CVT synthesis for producing 100g of MoSe2, respectively. CO2e and CO equivalents are also shown. [Modes for carrying out the invention]

[0136] The present invention relates in particular to a flash-within-flash-joule heating (FWF) method and system, the flash-joule heating method and system.

[0137] General non-equilibrium FWF Joule heating synthesis protocols have been found to possess an ultrafast heat transfer mechanism that provides rapid synthesis of various compounds in seconds. In this FWF process, flash Joule heating reactions can be performed, with the target starting material placed in a smaller reaction vessel inside a larger reaction vessel, which is then placed in a typical carbon-based flushing starting material. This allows the target starting material inside to react without contamination from the outer flushing starting material and without any constraints on the resistivity of the target starting material.

[0138] FWF overcomes the limitations of conventional equilibrium-based large-scale synthesis methods, enabling faster reaction rates and reducing reliance on solvents, water, and energy. Additionally, FWF provides a versatile, efficient, and scalable protocol for producing a wide range of inorganic compounds with excellent control over synthesis parameters for phase selectivity and single-crystal bulk powder production. FWF demonstrates flexibility in material modification through doping and gram scalability, offering environmentally friendly access to designed inorganic materials and significant cost reductions. Furthermore, diverse applications can be realized with FWF materials such as MoSe2 that outperform commercially available MoSe2 in tribological performance.

[0139] The FWF heating process is further distinguished from the FJH process by two characteristic heating methods: conduction heating and radiation heating. While FJH relies on a direct current flow to the material to induce resistance heating within the sample, FWF relies on the method of heat transfer. Conduction is generally dominant when there is a medium for heat transfer. When the FWF process is carried out under ambient conditions, in a pressurized system, in direct contact with the material being flash-joule heated, or for a short period of time, the primary method of heat transfer is conduction.

[0140] On the other hand, if the FWF process is performed under vacuum and does not involve direct contact with the material being flash-joule heated, or is performed for an extended period, radiative heating is preferred because there is no medium through which heat can proceed. Radiation includes wavelengths ranging from infrared to ultraviolet, depending on the temperature of the material being flash-joule heated.

[0141] Another mode of heating may result from an exothermic or endothermic reaction within the inner container. The inner tube may have a higher (or lower) temperature than the outer material being flash-joule heated if the inner reaction is exothermic (or endothermic).

[0142] Flash-within-Flash Joule Heating (FWF) Process Figure 1A provides a schematic diagram of a FWF used in one embodiment of the present invention. As shown in the pre-process schematic diagram 100, the FWF process involves using a system having two vessels (typically quartz vessels): an outer flushing vessel 103 filled with an inexpensive conductive material 105 such as metallurgical coke, and an inner semi-closed reactor 108 containing a target reagent 107 (precursor). The pre-process schematic diagram 100 shows that the system may further include a copper wool plug 104 (or graphite disk) that can come into contact with the conductive material 105 and the electrode 106 (graphite, copper, or any conductive refractory material).

[0143] As shown in schematic diagram 101 during the process, during the FWF process, the system is in ambient atmosphere and flash Joule heating (FJH) is applied to the outer vessel. The FJH process is carried out through a custom capacitor bank discharge system (Figure 2). [Deng II 2022]. The current 109 passes through the conductive material 105 in the outer vessel 103, resulting in resistance Joule heating and the generation of a high temperature of approximately 2000°C, measured by an infrared camera equipped with an alignment laser (Figure 1B). Figure 1B shows the current profile 121 and temperature profile 122 of the 340V FWF reaction. The dashed boxes 123–125 indicate the duty cycle regions of 10%, 20%, and 50%, respectively.

[0144] Subsequently, the intense heat 110 generated in the conductive material 105 of the outer vessel 103 is transferred to the inner vessel 108 through heat conduction, enabling ultra-fast heating of the reagent 107 in the inner tube 108. The voltage used to synthesize the materials can be varied in the range of 220V to 340V, etc., in the embodiments considered and described herein. To minimize the risk of explosion during the reaction and the potential damage to the custom-built condenser bank, the current flow was regulated using a pulsed duty cycle. This technique ensures that the current flow and corresponding resistance heating are evenly distributed throughout the sample during the 5-second reaction duration utilized. The pulsed discharge through the duty cycle also allows continuous changes in temperature, pressure, and volume to induce a non-equilibrium, kinetically controlled reaction while forming a specific target product 111 in the inner vessel 108, as shown in schematic Figure 102 after the process. [Dong 2022] Simultaneously, the outer container 103 of the conductive raw material 105 (which was metallurgical coke) is transformed into randomly layered graphene in a single reaction to provide additional value-added chemicals. The entire process takes less than 5 seconds, highlighting the ultrafast reaction rate of FWF.

[0145] The inner container does not need to contain a conductive material. This process can achieve crystal growth of, for example, some transition metal dichalcogenides. These target products in the inner tube are distinct from the conductive carbon reactant in the outer tube, which can then be converted back into other products such as chamoform flash graphene.

[0146] In the embodiment, the parameters for FWF Joule heating may include the following: a. The outer material responsible for Joule heating is conductive enough to allow current to flow, yet resistive enough for the current to heat the sample, generally between 1 and 10 ohms. b. Since the outer material is in electrical contact with the outer electrode, current can flow through the outer tube from one side to the other. c. There is no limit to the resistivity of the target material inside the inner tube. d. The inner material can, but does not necessarily, be in electrical contact with the outer material. The cap inside the inner container, as well as copper, graphite, or both, can allow current to pass through the inner container if they are electrically conductive. Alternatively, the cap inside the inner container, as well as a ceramic cap, can limit the current passing through the inner container. e. The inner reaction vessel may be made of quartz glass due to its chemical inertness, high thermal shock resistance, and high electrical resistivity. (In the examples herein, a quartz glass inner reaction vessel was used.) Alternatively or additionally, the inner reaction vessel may be or may include ceramic or concrete. f. This method enables the formation of products that are not typically formed or produced in high yield by conventional flash Joule heating. g. The chemical products of these reactions are generally oxidation products. h. This method can be used to synthesize single-crystal materials of comparable quality to those produced by chemical vapor deposition. i. When conductive carbon raw materials are used in the outer container, this carbon can be converted into high-quality randomized flash graphene and reused multiple times as raw material contents in the outer container. j. Outer raw materials to inner reactants in a mass ratio of approximately 8:1 can be used in these reactions. k. The reaction energy input per gram of internal raw material can be approximately 48 kJ / g to 90 kJ / g. l. These reactions can be carried out under vacuum, under ambient atmospheric conditions, or under other gases inside, or inside and outside, the reaction vessel.

[0147] The FWF process configuration complements the system and method for the synthesis of graphene by flash joule heating disclosed and described in the Tour '967 PCT application. The FWF method is used with pulse-width modulated DC electrical pulses, which are discharges in a capacitor bank, and can also be carried out using unmodulated DC, AC pulses, or a combination thereof. These reactions have been scaled down to 1 gram of target product in an inner vessel, and scaling far beyond that can be envisioned to tens or hundreds of kilograms.

[0148] Figures 3A–3F show FWF system protocols operating in radiant heating mode. Radiant heating is preferred when the FWF process is performed under vacuum, without direct contact with the material being flash-joule heated, or for extended periods. For these reaction environments, radiant heating is preferred because there is no medium for heat to propagate. Radiation includes wavelengths ranging from infrared to ultraviolet, depending on the temperature of the flash-joule heated material.

[0149] Figure 3A shows a scheme representing the graphite tube heater 300 (longitudinal section, tube support) of a device enabling radiant FWF heating. The viewpoint of the graphite tube heater 300 is longitudinal. The heating element is a tubular graphite foil (graphite double layer 312 and graphite single layer 313). The holder responsible for keeping the device rigid consists of three quartz tubes (covered with Cu foil), namely the outer quartz tube 303 (which may have an ID of 63 mm), the quartz tube sample holder 315 (which may have an ID of 8 mm and an OD of 12 mm), and a third quartz tube (not shown). Other features of the graphite tube heater 300 include a water cooling section 301, end plugs 302 (such as PTFE end plugs), nuts 304, springs 305, bushings 306 (such as ceramic bushings), shaft clamps 307, quartz tube support spacers 308 (which can be covered with Cu foil), threaded / tension rods 309 (such as 6-32 threaded / tension rods), radiation reflectors 310, shims 311 (such as Cu shims), tubes 314 (such as Cu or brass tubes with a 5 / 8 inch OD), N2316, a viewpoint 317 in the reflector, O-rings 318, and a vacuum 319. The springs 305 can maintain constant compression, the shaft clamps 307 are two-part shaft clamps with a 3 / 4 inch ID and a 2 inch OD, and the graphite sheets are 0.005 inch thick, can be narrowed in the center, and provide a single tubular layer. Figure 3A also does not show the wire connections at the copper tube ends of the graphite tube heater 300.

[0150] Figure 3B shows a cross-sectional scheme of the graphite tube heater 300, which allows for the evaporation and deposition of material on a desired substrate (metal or insulating material) of choice. The view of the graphite tube heater 300 is cross-sectional and further features the segmented sleeve 325 (such as a segmented Cu sleeve), the deposition plate 329 (such as a deposited Al or Cu plate), and the deposition plate 330 (such as a deposited carbon / graphite plate). Clamps and electrodes are shown by dashed lines within the graphite tube heater 300.

[0151] To change the length of the graphite tube heater 300, the tubular spacer 308 and the threaded / tension rod 309 must be cut to the appropriate length.

[0152] Figure 3C shows a scheme of a graphite tube heater 340 (longitudinal section, tube support) representing a device that enables radiant FWF heating. Similar to Figure 3A, the viewpoint of the graphite tube heater 340 is longitudinal. The heating element consists of a tubular graphite foil (graphite double layer 312 and graphite single layer 313) with four rods 343 (such as 4 mm quartz rods) (two of which are shown in Figure 3C) as support holders. The features of the graphite tube heater 340 are similar to those of the graphite tube heater 300, in which an O-ring retainer 341 is also shown.

[0153] Figure 3D shows a cross-sectional scheme of a graphite tube heater 340, which has four rods 343 as support holders, enabling evaporation and deposition of material on a desired substrate (metal or insulating material). The viewpoint of the graphite tube heater 340 is in the cross-sectional direction. Wraps and spacers 351 (such as Cu foil wraps and spacers) are also shown.

[0154] The graphite tube heater 340 offers easier length adjustment, however, it may be more fragile.

[0155] The graphite tube heaters 300 and 340 have radiation reflectors 310 to reduce losses from radiation that is about to be emitted.

[0156] In some embodiments, the inner material is non-conductive, and conductive materials cannot be easily added to the inner material (as this would affect the resulting product). In such cases, heat comes from the FJH process carried out in the outer vessel. In such situations, the plug of the inner vessel does not need to be conductive; for example, the plug of the inner vessel can be ceramic. However, there are embodiments in which it is advantageous for the inner vessel to have a plug on each end which is a conductive electrode. For example, the inner material is conductive by itself or becomes conductive during the FJH process. In such situations, the embodiment has an electric current passing through the inner material in the inner vessel, which can reduce the activation energy of the desired thermal process occurring in the inner vessel.

[0157] Figure 3E shows a scheme of the graphite tube heater 360, which is a graphite tube heater 340 with independent electric fields / currents to provide current through the inner raw material in the inner vessel during the FJH process. As shown in Figure 3E, a resistive or non-conductive sample 363 is positioned inside the inner quartz tube. Electrodes 369 connected to wire 361 are positioned at each end of the sample 370. Wire 361 is heat-resistant (such as nickel, tungsten, or carbon rod). Wire 361 is insulated outside the quartz tube. Wire 361 is connected to a high-voltage power supply 365 (AC, or DC). Wire 368, which provides the high current required to heat the tubular graphite heater, is clamped onto a copper (or brass) tube 314 with cable clamps 367. Wire 368 is connected to a welding power supply or power supply 366 that can provide high current. The end of the quartz sample holder tube can be sealed with a plug / fitting 364 (the fitting can allow for the introduction and recovery of gas). The tubular graphite radiant heater 360 can operate independently of the HV power supply 365. This allows for completely independent control for heating the sample and for applying an electric field or current directly to the sample 363.

[0158] By providing a fitting that allows for the introduction and recovery of gases, gases such as chlorine can be introduced into the sample 363 in the inner tube. Thus, the graphite tube heater 360 can be used to extract metals from ores and minerals, such as lithium from spodumene, by Joule heating or electrothermal chlorination. [Tour 556 application]

[0159] The graphite tube heater 360 can also be used to extract / remove iron from bauxite residue so that metals from waste such as (a) electronic waste such as printed circuit boards, or industrial waste such as carbon fly ash or bauxite residue (such metals can be metals essential to the electronics industry such as rare earth elements, gallium, tantalum, indium, or germanium), (b) metals from waste batteries such as lithium, cobalt, nickel, or manganese, and (c) the remaining aluminum can be further refined.

[0160] Figure 3F shows a scheme using a rigid graphite tube 370 as a heating element where the thinner graphite acts as the heating zone due to the difference in resistance. The rigid graphite 370 is machined to be thinner in the middle. For example, for a rigid graphite tube 380 with a longitudinal length 375 of 3.8 inches (having an ID of 0.5 inches 372 and an OD of 1 inch 374), the middle section length 373 can be 1.4 inches, and the annular space length 372 can be approximately 0.03 inches (i.e., the outer diameter of the middle section is approximately 0.53 inches). Such a rigid graphite tube 370 has higher resistance in the middle section where heating occurs. The rigid graphite tube 370 can be used in the race of tubular graphite foil in graphite tube heaters 300, 340, and 360. Larger shaft clamps can also be used to accommodate larger end diameters.

[0161] Figure 4 shows the workflow of a typical flash Joule heating process for a FWF reaction, and further summarizes it as follows. a. In step 401, the reactants were mixed and measured. For example, the target reactant raw materials were mixed in a mortar and pestle in the desired weight ratio. The total mass of this mixture was approximately 500 mg. b. In step 402, the reactants are filled into the inner container and cap. For example, a mixture of reactant raw materials was placed in a small quartz tube. The tube was capped at both ends with an inert material. i. The quartz tubes were generally 4 cm long, with an inner diameter of 8 mm and an outer diameter of 10 mm. Therefore, the width of the tube wall was only 1 mm. The cap was typically made of a graphite cylinder that frequently contacted a cylindrically wound copper thread, referred to as a spacer. The copper thread may extend outward from the tube if better electrical contact with the inner sample was desired. The cap could also be made of an insulating ceramic material. c. In step 403, the conductive raw materials are measured. For example, carbon raw materials were selected so that the overall resistance of the main reaction vessel was 1 to 10 Ω. Unless otherwise specified, small lumps of metallurgical coke measured in 4 to 5 grams (mainly 5 grams) were typically used in almost all of the synthesis discussed herein. In this case as well, metallurgical coke is a common raw material for FWF. i. In such tests, the metallurgical coke used was obtained from SunCoke. It was then crushed and sieved through a 0.30–0.84 mm sieve. Note that this is finer than the metallurgical coke used in conventional flash joule heating when producing graphene. d. In step 404, the outer tube is filled with the inner tube (containing the reactants) and conductive material, and then capped. For example, a quartz tube was selected and one end was capped with a graphite electrode. Often, a copper spacer was placed inside the graphite electrode. The outer tube was filled with approximately one-third of the selected metallurgical coke. The filled inner reaction tube was then positioned inside the outer tube above the conductive material (metallurgical coke). The remaining metallurgical coke was then poured around the inner tube so that the metallurgical coke surrounded the inner tube on all sides. The outer tube was then capped with a second graphite electrode and an optional copper spacer. The tube was then compressed longitudinally to improve electrical contact. i. The outer tubes were generally 10 cm long and had an inner diameter of 16 mm and an outer diameter of 20 mm. The inner tubes were typically located exactly in the center of the outer tubes. When measured across the two outer graphite electrodes, the resistance of these nested tubes was generally about 2–5 Ω. e. In step 405, the FWF process is performed. For example, DC flash Joule heating was then performed on a nested tube. Current was passed from one of the outer graphite electrodes through the metallurgical coke in the outer tube to the other graphite electrode. For a reaction of this size, an energy of 24–45 kJ was typically used. The flash was performed using a pulse-width modulated DC signal with a three-stage duty cycle pattern of 10% for 1 second, 20% for 0.5 seconds, and 50% for 5 seconds. f. In step 406, the generated target is removed from the inner tube, and in step 407, the product is removed from the outer tube.

[0162] Inner tube temperature and reaction kinetics Measuring the inner tube temperature is crucial for understanding the synthesis environment and dynamics, and by utilizing the synthesis-temperature-composition relationship, the FWF process can be further optimized. Measuring the inner tube temperature was attempted by moving the inner tube to the surface of the outer tube before performing a model FWF reaction that converts tin(II) chloride dihydrate (SnCl2·2H2O) and sulfur to tin disulfide, as shown in Figures 5A–5F. The configuration shown in Figure 5A allows for the measurement of the outer tube temperature, as described above (Figure 1B). The configuration shown in Figure 5B allows an infrared thermometer equipped with an alignment laser to measure the inner tube temperature during the FWF process. (For both temperature measurements in Figures 5A–5B, the laser-assisted thermometer is positioned 10 cm above the sample. The current flow may differ between the two configurations because the resistance may differ due to the packing of metallurgical coke for the configuration on the right compared to the configuration on the left. Nevertheless, the total energy input remains constant.) See also Figure 5C. The samples in both configurations exhibited similar resistances of 1.5Ω, providing a good comparison between the modified FWF process and the standard FWF process. The inner tube showed a much higher maximum temperature (approximately 2550°C) than the outer tube (approximately 2000°C). This unexpected result led to an investigation into what other heat sources might be contributing to the higher inner tube temperature.

[0163] To accurately describe the inner tube temperature, the total heat (dQ / dt) was expressed as follows as a function of three important heat sources: Stefan-Boltzmann radiant heating (E rad ), heat conduction heating from external FJH reaction (E TCH ), and the heat of reaction (E ΔH Equations (1) to (4) with the following parameters were used to calculate the heat source contributing to the inner tube temperature.

number

number

number

number

[0164] Due to the short reaction time, the contribution of radiative heating is calculated to be minimal, and this is because the heat of reaction (E) ΔH This suggests that ΔH is the main contributing factor to the higher temperature of the inner tube compared to the outer tube. Since enthalpy is a function of state and can only be measured when the reaction is in equilibrium, accurate measurement of ΔH was impossible. Nevertheless, the total amount of heat released during the reaction and the heat release rate were estimated by calculating the enthalpy of the reaction at a given temperature and measuring the time-dependent change in the inner tube temperature for the reaction of interest. For example, the enthalpy of the reaction to synthesize SnS2 at 2000°C is approximately -410 kJ / mol. Since the total amount of SnCl2·2H2O used in this reaction was 1.0 g, the maximum heat that the inner reactants could release was 1.8 kJ. The time required for this reaction to complete can be estimated from the time when heating stopped. Since heat release stopped 0.4 seconds after the FWF process, the heat release rate for this reaction is estimated to be 4.5 kJ·s. -1 This is what I calculated.

[0165] Using equations (1) to (4), the simulated temperature profile represented the internal tube temperature by solving the differential equations. As shown, when the reaction heat release is 2 kJ, the temperature profile is similar to the observed temperature of approximately 2550°C (approximately 2500°C). Figure 5B. This result indicates that the heat released during the reaction significantly affected the result and varied across the different FWF reactions carried out as discussed and described herein. Therefore, careful consideration of the specific reaction of interest was necessary to accurately represent the internal tube temperature.

[0166] FWF reaction type The FWF process can be further refined in other ways. For example, by adapting different reaction designs, certain problems such as slow rates and side reactions can be mitigated, thereby producing materials that would be difficult to prepare by other methods. One type, referred to herein as “Type 1 reaction,” is shown in the schematic diagram in Figure 1A, as discussed above.

[0167] Another type, referred to herein as “Type 2 reaction,” is shown in Figure 1C and involves flushing 2 to 5 times consecutively to address the problem of partial conversion. Figure 1C shows a schematic diagram 131 before the process with the target reagent 133 (precursor), and a schematic diagram 132 after the process with the target product 135 after 2 to 5 consecutive reactions 134. For example, the initial attempt to convert tungstic acid (WO3·H2O) to WS2 did not result in a complete conversion, as indicated by the presence of an unreacted precursor in XRD analysis. This was thought to be due to a slow reaction rate. However, when a consecutive FWF reaction was performed, a nearly complete conversion was achieved. XRD data showed a decrease in the signal of the starting WO3 with each subsequent reaction, suggesting a nearly complete conversion from WO3 to WS2 over three FWF reaction cycles.

[0168] Another type, referred to herein as a “Type III reaction,” is an anion exchange reaction, shown in Figure 1D, which can also address reactions that impose difficulties due to unexpected side reactions. Figure 1D shows a schematic diagram 141 before the process with the target reagent 143 (a metal precursor having SeS2), and a schematic diagram 142 after the process with the target product 145 (anion exchange product) after the anion exchange reaction 144 (promoted with S or Se). For example, a side reaction between Bi(NO3)3·5H2O and Se leads to the generation of brown gas (all reactions were carried out in a well-ventilated fume hood). After performing FWF with these solid precursors, the resulting product was a mixture of BiSeO2 and BiSeO5, indicating that the gas release was due to an unexpected oxidation reaction. By using a Type III reaction, this undesirable oxidation reaction was successfully avoided. Using Bi(NO3)3·5H2O and SeS2, Bi2Se3 was synthesized, thereby initially Bi2S x Se y This was obtained. Next, this intermediate was treated with Se to promote the anion exchange reaction. Similarly, by changing the added chalcogen to S, Bi2S3 was obtained. X-ray diffraction (XRD) analysis shows that a complete conversion has occurred to produce either pure Bi2S3 or pure Bi2Se3, as desired.

[0169] Typical synthesis methods Unless otherwise specified, all reagents used in these representative synthesis methods were used as received from the manufacturer. Unless otherwise specified, all reactions were carried out using type 1 reactions.

[0170] SnS2 Using a mortar and pestle, 0.25 g of SnCl2·2H2O (Alfa Aesar, reagent grade) was ground together with 0.25 g of sulfur (Millipore-Sigma). The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. The tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 340 V. The resulting powder was collected without further purification or washing.

[0171] SnS x Se y Using a mortar and pestle, 0.25 g of SnCl2·2H2O was ground together with 0.48 g of selenium sulfide. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 340 V. The resulting powder was collected without further purification or washing.

[0172] SnSe2 Using a mortar and pestle, 0.25 g of SnCl2·2H2O was ground together with 0.26 g of selenium. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 340 V. The resulting powder was collected without further purification or washing.

[0173] SnSe2-gram scale Using a mortar and pestle, 1.0 g of SnCl2·2H2O was ground together with 1.05 g of sulfur. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 340 V. The resulting powder was collected without further purification or washing.

[0174] Bi2S3-1 type Using a mortar and pestle, 0.25 g of Bi(NO3)3·5H2O(Millipore-Sigma) was ground together with 1.0 g of sulfur. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 300 V. The resulting powder was collected without further purification or washing. Note that material synthesis can be carried out through both direct flash (Type 1) or anion-exchange flash (Type 3).

[0175] Bi x S y Se z Using a mortar and pestle, 0.25 g of Bi(NO3)3·5H2O was ground together with 0.25 g of selenium sulfide (Millipore-Sigma). The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 340 V. The resulting powder was collected without further purification or washing.

[0176] Bi2S3-anion exchange pathway (type 3) Using a mortar and pestle, add 0.25 g of as-prepared Bi2S x Se yIt was mixed with 1.0 g of S. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 340 V. The resulting powder was collected without further purification or washing.

[0177] Bi2Se3-anion exchange pathway (type 3) Bi(NO3)3·5H2O(Millipore-Sigma) immediately forms a brown gas when mixed with Se(Millipore-Sigma). Therefore, an anion exchange pathway was applied rather than a direct synthesis pathway for Bi2Se3. Figure 1D. Using a mortar and pestle, 0.25 g of as-prepared Bi2Se3 was obtained. x Se y It was mixed with 1.0 g of Se. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 300 V. The resulting powder was collected without further purification or washing.

[0178] NiS2 Using a mortar and pestle, 0.25 g of Ni metal powder (Millipore-Sigma, <150 μm particle size) was ground together with 1.0 g of sulfur. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 220 V. The resulting powder was collected without further purification or washing. Trace amounts of NiS were detected in the XRD spectrum.

[0179] NiSe2 Using a mortar and pestle, 0.25 g of Ni metal powder was ground together with 1.0 g of Se. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 340 V. The resulting powder was collected without further purification or washing.

[0180] CoS2 Using a mortar and pestle, 0.25 g of Co(II,III) oxide (Millipore-Sigma, particle size <50 nm) was ground together with 1.0 g of sulfur. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 340 V. The resulting powder was collected without further purification or washing.

[0181] CoS x Se y Using a mortar and pestle, 0.25 g of Co(II,III) oxide was ground together with 1.0 g of selenium sulfide. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 340 V. The resulting powder was collected without further purification or washing.

[0182] CoSe Using a mortar and pestle, 0.25 g of Co powder (Millipore-Sigma, -100 mesh) was ground together with 1.0 g of selenium. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 300 V. The resulting powder was collected without further purification or washing.

[0183] MoSe2 Using a mortar and pestle, 0.25 g of Mo metal powder (Alfa Aesar, APS 3-7 microns) was ground together with 1.0 g of selenium. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 300 V. The resulting powder was collected without further purification or washing.

[0184] WSE2 Using a mortar and pestle, 0.25 g of W metal powder (Alfa Aesar, APS 1-5 microns) was ground together with 1.0 g of selenium. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 300 V. The resulting powder was collected without further purification or washing.

[0185] WSe2 Gram Scale Using a mortar and pestle, 1.0 g of W metal powder was ground together with 1.3 g of Se. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 340 V. Due to the rapid volume expansion and gas release of Se during the reaction, it was impossible to achieve 100% recovery of the powder. The residual powder in the inner tube was collected without further purification or washing. The collected powder was weighed, and the recovery rate was 59%, with a conversion rate of approximately 100%. See Figures 5A-5D.

[0186] NbSe2 Using a mortar and pestle, 0.25 g of Nb metal powder (Thermo Scientific, -325 mesh) was ground together with 0.67 g of selenium. For Nb, the molar ratio of Nb to Se is important because Nb further reacts with Se to produce Nb2Se9. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 300 V. The resulting powder was collected without further purification or washing. Small amounts of unreacted Nb were detected in the XRD spectrum.

[0187] FeS2 Using a mortar and pestle, 0.25 g of Fe2O3·xH2O (Millipore-Sigma, catalyst grade, 30-50 mesh) was ground together with 1.0 g of sulfur. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 220 V. The resulting powder was collected without further purification or washing. The XPS of the resulting powder showed a high oxygen concentration, suggesting that further modifications, such as a type II reaction, may be required to prepare a cleaner material.

[0188] α-In2Se3 (Alpha-phase In2Se3) 0.42 g of In metal teardrop shot was mixed with 0.84 g of Se. The resulting mixture was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. The tube was flash-heated at 300 V. The resulting powder was collected without further purification or washing.

[0189] TiSe2 Using a mortar and pestle, 0.25 g of Ti metal powder (Johnson Matthey Catalog Company, -325 mesh) was ground together with 1.0 g of Se. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 300 V. The resulting powder was collected without further purification or washing.

[0190] Cu 0.87 Se Using a mortar and pestle, 0.25 g of Cu metal powder was ground together with 1.0 g of selenium. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 300 V. The resulting powder was collected without further purification or washing.

[0191] cu9S5 Using a mortar and pestle, 0.25 g of Cu metal powder was ground together with 1.0 g of sulfur. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 300 V. The resulting powder was collected without further purification or washing.

[0192] Cu2Se-by-product The flash-within-flash reaction, carried out using more than 1 g of selenium powder in the inner tube, resulted in the release of selenium gas into the outer tube. This high-flux gas release caused the copper wool (acting as a spacer) to react with the selenium gas. The resulting crystals were crushed, and the powder was collected without further purification or washing.

[0193] TiN Using a mortar and pestle, 0.25 g of Ti metal powder (Johnson Matthey Catalog Company, -325 mesh) was ground together with 1.0 g of selenium. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 340 V. The resulting powder was collected without further purification or washing.

[0194] LaBO3 Using a mortar and pestle, 0.25 g of La(NO3)3·6H2O powder (Millipore-Sigma) was ground together with 0.5 g of amorphous boron. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 340 V. The resulting powder was collected without further purification or washing.

[0195] WS2*-Multiple Flash (Type 2) Using a mortar and pestle, 0.25 g of WO3·H2O (Millipore-Sigma) was mixed with 1.0 g of sulfur. The resulting powder was placed in an 8 mm quartz tube with graphite spacers and protruding copper wires at each end. This tube was then placed inside a 15 mm quartz tube, which was subsequently filled with 5.0 g of metallurgical coke. These tubes were flash-heated at 340 V. Due to the incomplete conversion of the initial precursor and significant residue, the reaction was carried out two more times (a total of three times) using the as-synthesized powder and 1.0 g of sulfur to convert the initial tungstic acid to WS2. Trace amounts of tungstic acid were observed.

[0196] Products and doping / substitution capabilities The FWF method can be used for the general synthesis of various compounds. As discussed above, by controlling voltage and reagents individually, 10 TMDs, 3 Group 14 dichalcogenides, and 9 non-TMD materials have been prepared as representative examples. Figure 7A, Table I. [Table 1]

[0197] Characterization by XRD, XPS, and / or (scanning) transmission electron microscopy (S / TEM) demonstrates successful synthesis and highlights the consistent generation of the desired product. A variety of solid reagents can be employed, including metal powders (e.g., Ni, Mo, W), metal chlorides (e.g., SnCl2·2H2O), metal oxides (e.g., cobalt(II,III) oxide, iron oxide hydrate), metal nitrates (e.g., Bi(NO3)3·5H2O), and hydrated salts as precursors. The voltage for each reaction was optimized to produce the desired final product. Figure 7B. The initial input voltage was directly related to the input energy; i.e., the total amount of energy delivered to the reaction can be calculated using the following equation:

number

[0198] The corresponding energy (kJ) per gram of metallurgical coke is also shown. However, the inner tube temperature should be calculated and measured to represent the total heat released and the heat release rate, respectively, as in our method described above. This versatile synthesis technique overcomes the limitations of other synthesis protocols, such as hydrothermal synthesis, where solubility and the type of initial precursor play a crucial role in forming the desired product, as well as the conductivity requirements of carbon thermal, thermal shock methods, including FJH [Joo 2011]. While the majority of compounds synthesized in this experiment focused on sulfides, selenides, and layered materials [Du 2020; Feng 2022], the formation of titanium nitride (TiN) and lanthanum borate (LaBO3) was demonstrated, suggesting that FWF can serve as a general method for synthesizing a wide variety of inorganic compounds.

[0199] Doping (substitution) of various compounds using FWF is also possible simply by changing the initial precursor. We observed reagent-dependent tunability and doping ability using three different chalcogen-based reagents, S, SeS2, and Se, as the corresponding anions in the Sn-based system. See Figures 7C-7E. Atomic-resolution images of SnS2 (Figure 7C) and SnSe2 (Figure 7D), as shown by annular dark-field scanning transmission electron microscopy (ADF-STEM) and energy-dispersive X-ray spectroscopy (EDX), indicate successful synthesis of these compounds; EDX also showed similar results to ADF-STEM imaging detecting Sn and S or Se, respectively. Notably, Se-doped SnS2 (SnS) was synthesized simply by substituting the initial precursor with SeS2. x Se y (shown as shown) formed (Figure 7E). The EDX spectrum showed a uniform distribution of highly crystalline Se, as observed in the ADF-STEM image. Due to the 2:1 ratio between S and Se, SnS x Se y The Raman spectra and XRDs of the flakes exhibit similar characteristics to those of SnS2. Additionally, all flakes analyzed by S / TEM (scanning / transmission electron microscopy) showed single-crystal orientation (Figures 8A-8D), further demonstrating the phase-selective and single-crystal bulk powder-producing ability of the FWF, a result rarely observed with other non-equilibrium methods.

[0200] As shown in inset 901 in Figure 9B, for SnSe2, a small amount of SnO2 was formed on the surface, as confirmed by the XRD spectrum shown in Figure 9A (also confirmed by EDX mapping (see Figure 7D)). As further shown in insets 901-903 in Figure 9B, the color of the powder changed from yellow (SnS2) to red (SnS x Se ychanges dramatically in ], indicating that doping and misalignment cause band gap shifts in the material. [Chen 2011; Choi 2018]. This provides a simple and rapid method for doping other atoms into a system, and demonstrates doping procedures for applications in electronic devices [Shi 2020], catalysts [Dou 2020], and energy storage. [Zhu L 2023; Zhu W 2023].

[0201] Electron microscopy characterization and electrical properties of FWF materials FWF enables phase-controlled material synthesis. ADF-STEM images of MoSe2 and WSe2 (Figures 7F-7G) show that these materials exhibit a hexagonal atomic arrangement along with a 2H phase and AB stacking, and present their energetically favorable structure in the analyzed flakes. [Foerg 2021]. In contrast to the previous FJH method that produced metastable flash graphene with turbostratic structure [Luong 2020], FWF does not involve current passing through the sample during synthesis. This may account for the highly ordered arrangement of stacking. For In2Se3, only the alpha phase (α-In2Se3) was present in the flakes as shown by ADF-STEM imaging (Figure 7H) and XRD, indicating that the currently optimized FWF is a selective process. [Han 2023].

[0202] Since these synthesized materials can be widely adopted in many semiconductor applications, it is important to understand the electrical properties of FWF products. MoSe2, WSe2, and α-In2Se3 flakes were selected as representative targets because they exhibit n-type semiconductor, p-type semiconductor, and n-type ferroelectric behavior, respectively. To characterize the electrical properties, FWF materials were mechanically exfoliated, and field effect transistor (FET) device 1000 was fabricated on a SiO2 / Si substrate 1001 by a conventional photolithography method. Figure 10A.

[0203] For the fabrication of device 1000 shown in the schematic diagram of Fig. 10A, MoSe₂ 1007, WSe₂ 1008, and α-In₂Se₃ 1009 (both FWF α-In₂Se₃ and commercial single-crystal α-In₂Se₃ purchased from 2D Semiconductors®) samples were respectively prepared using a typical mechanical exfoliation method on SiO₂ (285 nm) / Si substrates. The thickness of these layers was verified by optical contrast, and subsequently their thickness was determined using cross-sectional TEM. To form electrical contacts, source 1003 and drain 1002 patterns with a channel length of 3 μm were fabricated using conventional photolithography, and 50 nm of Au metal was deposited at approximately 10 -8 Torr pressure and a deposition rate of 2.0 Å·s -1 by an electron beam evaporator under the above deposition rate conditions. To remove residual photoresist, the samples were immersed in an acetone bath for 6 hours to 12 hours, and then the solution was gently blown off with N₂ gas. Finally, to improve the interfacial contact properties between the metal and the two-dimensional material, the fabricated device was stored under vacuum (approximately 10 -3 Torr) conditions for 6 hours to 12 hours. Drain voltage (V D ) 1004, gate voltage (V G ) 1005, and grounded source electrode 1006 are further shown in the schematic diagram of device 1000 presented in Fig. 10A.

[0204] Cross-sectional ADF-STEM and energy dispersive X-ray spectroscopy (EDX) analyses were performed to obtain atomic-resolution images of the device along with its components (1011 to 1013 in Fig. 10B for MoSe₂, WSe₂, and α-In₂Se₃, respectively), which show the layered structure, clean interface, and uniform atomic distribution.

[0205] To verify the electrical characteristics of the as-synthesized materials, transfer curves and output curves were investigated. For MoSe₂, the transfer curve exhibited an on-current when a positive gate bias was applied regardless of the drain voltage. Fig. 10C (V DThe graph has plots 1021-1022 for 0.1V and 1V, and inset 1023 shows an optical image of this FET device. In addition, the output curve shows a higher drain current when the gate bias is positive (Figure 10F, V, respectively). D Plots 1059, 1053, 1052, and 1051 for -40V, 20V, 30V, and 40V are shown, illustrating its n-type characteristics. [Jung 2015]. Conversely, for WSe2, the transfer curve showed the on-current when a negative gate bias was applied, regardless of the drain voltage. Figure 10D (V, respectively) D The graph has plots 1031-1032 for 0.1V and 1V, and inset 933 shows an optical image of this FET device. Similarly, the output curve shows higher current when the gate bias is negative (Figure 10G, V D Plots 1063, 1065, 1066, 1067, 1068, and 1051 for =20V, 0V, -10V, -20V, -30V, and -40V show typical p-type characteristics. [Kim 2023] This shows that the FWF technique can produce n-type and p-type semiconductor flakes, 1.1 × 10⁻¹⁰ for MoSe2. 6 On / off ratio and 6.81cm 2 · V -1 · s -1 It was shown that the mobility of 1.74 × 10⁻¹⁰ is achieved for WSe2. 4 On / off ratio and 2.96cm 2 · V -1 · s -1 The mobility level was achieved.

[0206] α-In2Se3 (Figure 10E, each of the following: V DIn the case of plots 1041-1042 for 0.1V and 1V (and inset 1043 showing an optical image of this FET device), the transfer curve demonstrated an on-current with a positive gate bias, which is typical n-type semiconductor behavior. However, this curve also showed a clockwise hysteresis loop due to the ferroelectric characteristics of α-In2Se3 [Si 2019]. Further endurance testing was performed to observe the set / reset characteristics of α-In2Se3. During the endurance testing, the following sequence was repeated 1000 times: a gate voltage of -40V with a pulse width of 1 second was applied to set the device, and then the channel current was measured by a drain voltage of 1V. Subsequently, a gate voltage of +40V with a pulse width of 1 second was applied to reset the device, and then the channel current was measured by a drain voltage of 1V.

[0207] As shown in Figure 10H, approximately 10 2 No performance degradation was observed over 1,000 cycles with a high on / off ratio, suggesting high durability comparable to chemical vapor deposition-grown α-In2Se3 [Si 2019]. The results demonstrate that materials produced in non-equilibrium FWF exhibit extremely superior electrical properties, which can facilitate the development of various devices with two-dimensional materials and encourage fundamental research into these materials, which are now readily accessible on a gram scale at a lower cost (further details below).

[0208] We demonstrated the comparability of performance between commercially available single-crystal α-In2Se3 and FWF α-In2Se3 by comparing them. Since the device geometry and pre / post-processing must be identical for a valid comparison, our FWF α-In2Se3 device was compared to a commercially available single-crystal α-In2Se3 (2D Semiconductors®) device fabricated under identical conditions. The power and transfer curves, with a positive gate bias, exhibited the expected higher drain current and clockwise hysteresis loop, along with the on-current, demonstrating ferroelectric n-type semiconductor performance. Endurance tests demonstrating set / reset characteristics were also performed. Compared to FWF, the transfer curve, power curve, and endurance performance were all equivalent between the FWF material and the commercially available single crystal.

[0209] Table II summarizes previously reported research results. Linear comparisons between reported research results and the devices disclosed and taught herein for MoSe2, WSe2, and α-In2Se3 are unreliable due to different geometries and fabrication protocols. Therefore, it was necessary to provide a device performance comparison between commercially available α-In2Se3 single crystals and our FWF α-In2Se3 to demonstrate electronic similarity. [Table 2]

[0210] Comparison of Tribology and Friction Coefficient A comparative analysis of the coefficient of friction (COF) between commercially available MoSe2 and FWF MoSe2 demonstrated superior and stable tribological performance. For tribological performance measurement, samples were prepared by coating alumina substrates with commercial MoSe2 powder (Millipore-Sigma) and FWF MoSe2 powder. The powder was applied directly to the substrate and carefully spread by rubbing it across the surface in a circular motion for 5 minutes to break down heterogeneity and achieve integration of the additive as a coating. A tribometer with a ball-on-flat configuration was used to evaluate the tribological properties of the samples in sliding reciprocating motion. In this test, a 6 mm diameter chromium steel 52100 ball was slid against a rectangular flat alumina sample under the following different loading conditions: 1 N, 5 N, and 10 N for 10 minutes at a frequency of 3 Hz. The coefficient of friction was measured at a sampling rate of 100 data points per second and reported as a function of time. The mass of the coating was 0.2 g.

[0211] Figure 11A shows the time-dependent change in COF for 120,000 measurements of reference alumina (indistinct square 1101), commercial MoSe2 (indistinct circle 1102), and FWF MoSe2 (indistinct triangle 1103). Moving average trend lines for reference alumina (line 1104), commercial MoSe2 (line 1105), and FWF MoSe2 (line 1106) under 1N are shown simultaneously. As shown in Figure 11A, in the initial stages of the experiment, the COF for commercial MoSe2 and FWF MoSe2 were virtually indistinguishable. However, after 2 minutes of operation, a significant increase in COF for commercial MoSe2 was observed.

[0212] Similarly, FWF MoSe2 outperformed commercial MoSe2 under different loads. Figure 11B (bars 1011–1013 for alumina, commercial MoSe2, and FWF MoSe2, respectively). The coefficient of friction showed reductions of 69%, 20%, and 41% at applied loads of 1N, 5N, and 10N, respectively. These results reveal that the commercial MoSe2 film decomposed and / or wore down at a faster rate than the FWF MoSe2 film, indicating a difference in the quality of the initial powder.

[0213] EDX analysis was performed on these two flakes to investigate impurity concentrations. Neither material showed distinguishable impurity concentrations, indicating that impurities are not the cause of the performance difference. Low concentrations of oxygen impurities in FWF MoSe2 may be due to efficient gas release. A careful mathematical model was constructed to explain the behavior of oxygen vacancies in MoSe2 when exposed to the extreme heat generated during the FWF process.

[0214] To study degassing calculations using density functional theory (DFT) [Dudarev 1998], the formation energy of O substitution of Se in the MoSe2 crystal structure was calculated using the following equation:

number

[0215] The chemical potential of O2 gas as a function of pressure p and temperature T was calculated according to the following equation [Reuter 2001]:

number

[0216] The DFT method was used because it is implemented in the Vienna Ab-initio Simulation Package (VASP) [Kresse 1996]. Plane wave expansion up to 500 eV was employed in combination with an all-electron-like projector extended wave (PAW) potential [Bloechl 1994]. Exchange correlation was handled in the generalized gradient approximation (GGA) using a function parameterized by Perdew-Burke-Ernserhof [Perdew 1996]. Periodic conditions were applied to the supercell or unit cell of the crystal structure so that the Brillouin zone integral converges on a Monkhorst-Pack type mesh [Monkhorst 1976]. Structural optimization using the conjugate gradient algorithm implemented in VASP fully relaxes both the atomic positions and the unit cell so that the maximum force on each atom is less than 0.01 eV / Å.

[0217] The governing equation represents the formation energy of oxygen vacancies in MoSe2 relative to free oxygen molecules. This equation is dependent on internal pressure and temperature. The free energy is positive around 2000K, regardless of pressure, indicating that oxygen vacancies were effectively eliminated during synthesis. The minute oxygen signal in EDX may be due to adsorbed air and possible self-limiting native oxide layer formation.

[0218] The cause of the difference between the two materials is demonstrated at the edges of flakes of commercially available MoSe2, which exhibit an amorphous layer with a thickness of about 10 nm. Figures 12A to 12B. In comparison, FWF MoSe2 shows little or no amorphous edges, and ADF-STEM atomic resolution images show distinct crystal edges. Figures 12D to 12E. Selected area electron diffraction (SAED) patterns indicated the presence of polycrystalline and amorphous components in commercial MoSe2 (Figure 12C), whereas single crystallinity is observed for FWF MoSe2 (Figure 12F).

[0219] This excellent and stable performance is attributed to the single-crystal nature of FWF MoSe2, which results in an overall lower friction coefficient and improved tribological performance. [Liu 2018; Lee 2010; Huang 2018]. Due to the distinct lamellar orientation of FWF MoSe2 coating materials, these sheets can easily slide against each other, thereby reducing resistance to movement and consequently reducing the friction coefficient.

[0220] FWF Gram Scalability A very outstanding advantage of the FWF method is its scalability to gram-scale production without complexity. Such high scalability is rarely observed in laboratory chemical synthesis, which often requires additional engineering, equipment setup, and / or alternative synthetic routes to ensure complete conversion of materials. [Li 2021]. In contrast, FWF can be easily scaled by adjusting the voltage to accommodate an increase in the amount of reactants.

[0221] Furthermore, the semi-closed inner reactor plays a crucial role in enabling efficient gas release and facilitating the incorporation of highly volatile reagents such as chalcogens. Additionally, gas release prevents oxygen penetration and inhibits cracking of the inner tube. As discussed and explained above (WSe2-gram scale), the scalability of FWF was demonstrated by synthesizing WSe2 from W and Se precursors, successfully achieving simple gram-scale production. See Figures 6A–6D. Figure 6A shows 1.11 g of WSe2 synthesized in a single reaction. XRD analysis (Figure 6B) and X-ray photoelectron spectroscopy (XPS) spectra (Figures 6C–6D) show high-purity crystalline WSe2 without any identifiable by-products or initial precursor residues. This representative WSe2-gram scale FWF synthesis reveals the exceptional scalability of the FWF process.

[0222] Lifecycle Assessment (LCA) of FWF Life cycle assessments (LCAs) of nanomaterials and processes not yet industrialized can be challenging due to the wide range of field heterogeneities and product class diversity. For example, TMDs can be synthesized by various different methods, including modified chemical vapor transport (CVT) or deposition processes, and flux growth methods. For a simple direct comparison of the FWF method, only synthesis methods yielding similar products were considered. Thus, methods capable of producing single crystals, multilayers, and low defect density MoSe2 were considered, rather than methods producing monolayers, high-defect layers, or polycrystalline layers. Most TMDs that cannot be exfoliated from naturally occurring minerals such as MoS2 and WS2 exist on a very small production scale. Ultimately, while these other TMD products have high economic value, their market size is minimal and they are mainly limited to academic use. A small 100g functional unit of crystalline MoSe2 was used. This is because it can be considered laboratory scale and allows for comparison between published synthesis methods while minimizing the impact of assumptions associated with hypothetical pilot-scale production. The FWF reaction pathway was compared with the molten Mg autoclave reaction and the CVT flux growth method. It should be noted that CVT flux growth can grow larger crystals than the molten Mg and FWF reaction pathway.

[0223] A comprehensive life cycle assessment was conducted to compare the sustainability of FWF with Mg-assisted autoclave synthesis [Upadhyay 2021] and chemical vapor transport (CVT) methods [Ubaldini 2014] for synthesizing 100g of MoSe2 [Hellweg 2014]. These two methods were chosen because the final product exhibits similar characteristics such as multilayer and high crystallinity. Cradle-to-gate LCA classified cumulative energy demand (Figure 13A), global warming potential (Figure 13B), and cumulative water usage (Figure 13C). The LCA demonstrated that FWF synthesis of MoSe2 uses 56%–83% less energy, produces 71%–94% less greenhouse gases, and consumes 90%–97% less water compared to the autoclave and CVT methods, respectively. Estimated production costs (Figure 13D) were obtained by technical and economic assessment (TEA). The estimated TEA showed that even without the sale of flash graphene, FWF would bring significant cost reductions to the preparation of inorganic materials, making it an attractive option for manufacturing.

[0224] Uses and applications FWF Joule heating technique (a non-equilibrium ultrafast heat conduction method) can be used to prepare a variety of materials, including, for example, transition metal dichalcogenides (TMDs), group 14 dichalcogenides, and other non-TMD materials, each of which can be prepared in under 5 seconds under ambient conditions. Compared to other synthesis methods, FWF achieves significant advantages in terms of simple gram scalability and sustainable manufacturing standards. Furthermore, FWF enables the production of phase-selective and single-crystal bulk powders, phenomena rarely observed by any other synthesis method. In addition, FWF MoSe2 outperformed commercially available MoSe2 in tribology, demonstrating the quality of FWF materials. The ability to perform atomic substitution and doping further demonstrates the versatility of FWF as a general bulk inorganic material synthesis protocol. Thus, the FWF Joule heating technique advances inorganic material production while maintaining environmental awareness by providing sustainable manufacturing that prioritizes energy efficiency, minimal water usage, scalability, and the ability to produce a variety of materials.

[0225] FWF also makes it possible to achieve the formation of amorphous carbon (examples listed above) due to the absence of a current flowing directly through the material. This was one of the major hurdles that FJH could not overcome.

[0226] Therefore, embodiments of the present invention enable the rapid synthesis of gram-scale crystalline transition metal dichalcogenides, which is not normally possible to achieve simultaneously with this quality and speed. Industrially, this can be scaled to kilogram and multi-kilogram scale synthesis in seconds per batch. Battery performance using SnS2 as an anode has been well demonstrated. As shown, the capacity retention rate is nearly 99% after three initial cycles, which is a very high figure. Further optimization of conductivity (e.g., doping) can be used to enhance battery performance with higher capacity than graphite anodes.

[0227] These products are found within semiconductor devices, and their applicability to transistors in particular has also been demonstrated in this specification.

[0228] The products of the process according to the embodiments of the present invention can also be used in other optical and electronic devices.

[0229] Pulse schemes for applying voltage pulses to control a flash Joule heating mechanism through controlled electronic modulation can be useful in several embodiments. Such pulse schemes may include variable frequency drive (VFD), pulse width modulation (PWM), proportional-integral-derivative (PID) control, ternary control, and combinations thereof. Such controlled electronic modulation is discussed in Tour'193 PCT application, which is incorporated entirely herein.

[0230] Therefore, the process of the embodiments of the present invention is faster, more energy-efficient, and less expensive than other methods for producing gram-scale transition metal dichalcogenides. The crystallinity of the product is comparable to that produced by chemical vapor deposition, which takes minutes to hours to carry out.

[0231] These processes are also driven kinetically rather than thermodynamically, enabling the formation of products that cannot be synthesized through many other methods. Compared to conventional flash Joule heating, this method allows for the formation of products that cannot normally be formed.

[0232] While embodiments of the Disclosure have been shown and described, modifications thereof can be made by those skilled in the art without departing from the spirit and teachings of the Disclosure. The embodiments described herein and the examples provided herein are illustrative and not intended to limit. Many variations and modifications of the Invention disclosed herein are possible and within the scope of the Disclosure. The scope of protection is not limited by the foregoing description but is limited only by the following claims, which include all equivalents of the subject matter of the claims.

[0233] All patents, patent applications, and publication disclosures cited herein are incorporated herein by reference in their entirety, insofar as they provide exemplary, procedural, or other details that complement those described herein.

[0234] Quantitative and other numerical data may be presented herein in range form. Such range forms are used solely for convenience and brevity and should be understood to be interpreted flexibly to include all individual numbers or subranges contained within that range, as if each number and subrange were explicitly listed, rather than just the numbers explicitly enumerated as the limits of the range. For example, a numerical range of approximately 1 to approximately 4.5 should be interpreted to include not only the explicitly enumerated limits of 1 to approximately 4.5, but also individual numbers such as 2, 3, 4, and subranges such as 1 to 3, 2 to 4, etc. The same principle applies to ranges enumerating only one number, such as "less than approximately 4.5," which should be interpreted to include all the values ​​and ranges enumerated above. Furthermore, such interpretations should apply regardless of the breadth of the range or the characteristics described.

[0235] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the subject matter of this disclosure pertains. Any methods, devices, and materials similar or equivalent to those described herein may be used in the practice or testing of the subject matter of this disclosure, but representative methods, devices, and materials are described herein.

[0236] In accordance with long-standing patent law convention, the terms “a” and “an,” when used in this application, including in the claims, mean “one or more.”

[0237] Unless otherwise indicated, all numbers used herein and in the claims, such as amounts of compounding components and reaction conditions, should be understood in all examples to be modified by the term "approximately." Therefore, unless otherwise indicated, the numerical parameters described herein and in the appended claims are approximations that may vary depending on the desired properties required by the subject matter of this disclosure.

[0238] Where used herein, the terms “about” and “substantially” mean that when referring to a value or quantity of mass, weight, time, volume, concentration or percentage, such variation includes variations of ±20%, ±10%, ±5%, ±1%, ±0.5%, and ±0.1% from a given quantity, in some embodiments, because such variation is appropriate for performing the disclosed method.

[0239] As used herein, the terms “substantially perpendicular” and “substantially parallel” mean, in some embodiments, a variation of ±10° in the vertical and parallel directions, in some embodiments, a variation of ±5° in the vertical and parallel directions, in some embodiments, a variation of ±1° in the vertical and parallel directions, and in some embodiments, a variation of ±0.5° in the vertical and parallel directions.

[0240] As used herein, the term "and / or," when used in the context of listing entities, means that the entities exist individually or in combination. Thus, for example, the phrase "A, B, C, and / or D" includes A, B, C, and D individually, but also any and all combinations of A, B, C, and D, as well as partial combinations of A, B, C, and D.

[0241] References PCT Application No.PCT / US2019 / 047967, filed on August 23,2019, entitled“Flash Joule Heating Synthesis Method And Compositions Thereof,” to JM Tour et al.(“Tour'967 PCT Application”).

[0242] PCT Application No.PCT / US2024 / 010193,filed on January 3,2024,entitled“Methods For Controlled Joule Heating Of Materials For Gas Desorption And Systems For Performing Same,”to J.M Tour et al.(“Tour’193 PCT Application”),which claims priority to U.S.Patent Application No.63 / 437,021,filed January 4,2023,entitled“Methods For Controlled Joule Heating Of Materials For Gas Desorption And Systems For Performing Same,”to J.M.Tour,et al.

[0243] U.S.Patent Appl.Serial No.63 / 669,556,filed July 10,2024,entitled“Systems And Methods For Extraction Of Lithium From Spodumene,”to J.M.Tour et al.(“Tour’556 Application”).

[0244] Advincula,P.A.,et al.,“Flash Graphene from Rubber Waste,”Carbon,2021,178,649-656(“Advincula 2021”).

[0245] Algozeeb,W.A.,et al.,“Flash Graphene from Plastic Waste,”ACS Nano,2020,14(11),15595-15604(“Algoeeb 2020”).

[0246] Aykol,M.,et al.,“Rational solid-state synthesis routes for inorganic materials,”J.Am.Chem.Soc.,2021,143,9244-9259(“Aykol 2021”).

[0247] Bloechl,P.E.,“Projector augmented-wave method,”Phys.Rev.B,1994,50,17953-17979(“Bloechl 1994”).

[0248] Chase,M.W.,et al.,“JANAF thermochemical tables,1975 supplement,”J.Phys.Chem.Ref.Data,1975,4,1-176(“Chase 1975”).

[0249] Chaudhary,K.T.,et al.,“Multiwalled carbon nanotube synthesis using arc discharge with hydrocarbon as feedstock,”J.Nanomater.,2013,2013,1-13(“Chaudhary 2013”).

[0250] Chen,W.,et al.,“Boron-Carbon-Nitrogen and Boron-Nitride by Flash Joule Heating,”Advanced Materials,2022,34(33),2202666(“Chen 2022”).

[0251] Chen,W.,et al.,“Ultrafast and Controllable Phase Evolution by Flash Joule Heating,”ACS Nano,2021,15,11158-11167(“Chen I 2021”).

[0252] Chen,W.,et al.,“Millisecond Conversion of Metastable 2d Materials by Flash Joule Heating,”ACS Nano,2021,15,1282-1290(“Chen II 2021”).

[0253] Chen,Y.,et al.,“Ultra-fast self-assembly and stabilization of reactive nanoparticles in reduced graphene oxide films,”Nat.Commun.,2016,7,12332(“Chen 2016”).

[0254] Chen,X.,et al.,“Increasing solar absorption for photocatalysis with black hydrogenated titanium dioxide nanocrystals,”Science,2011,331,746-750(“Chen 2011”).

[0255] Chinwego,C.,et al.,“Technoeconomic analysis of rare-earth metal recycling using efficient metal distillation,”JOM,2022,74,1296-1305(“Chinwego 2022”).

[0256] Choi,C.H.,et al.,“Polymeric carbon nitride with localized aluminum coordination sites as a durable and efficient photocatalyst for visible light utilization,”ACS Catal.,2018,8,4241-4256(“Choi 2018”).

[0257] Chuang,H.-J.,et al.,“Low-resistance 2D / 2D Ohmic contacts:A universal approach to high-performance WSe2,MoS2,and MoSe2transistors,”Nano Lett.,2016,16,1896-1902(“Chuang 2016”).

[0258] Couteau,E.,et al.,“CVD synthesis of high-purity multiwalled carbon nanotubes using CaCO3catalyst support for large-scale production,”Chem.Phys.Lett.,2003,378,9-17(“Couteau 2003”).

[0259] Deng,B.,et al.,“Phase Controlled Synthesis of Transition Metal Carbide Nanocrystals by Ultrafast Flash Joule Heating,”Nat.Commun.,2022,13(1),262(“Deng I 2022”).

[0260] Deng,B.,et al.,“High-surface-area corundum nanoparticles by resistive hotspot-induced phase transformation,”Nat.Commun,2022,13,5027(“Deng II 2022”).

[0261] Dong,Q.,et al.,“Programmable heating and quenching for efficient thermochemical synthesis,”Nature,2022,605,470-476(“Dong 2022”).

[0262] Dou,Y.,et al.,“Approaching the activity limit of CoSe2for oxygen evolution via Fe doping and Co vacancy,”Nat.Commun.,2020,11,1664(“Dou 2020”).

[0263] Du,Z.,et al.,“Conversion of non-van der Waals solids to 2D transition-metal chalcogenides,”Nature,2020,577,492-496(“Du 2020”).

[0264] Dudarev,S.L.,et al.,“Electron-energy-loss spectra and the structural stability of nickel oxide:An LSDA+U study,”Phys.Rev.B,1998,57,1505-1509(“Dudarev 1998”).

[0265] Feng,Y.,et al.,“Synthesis of noble metal chalcogenides via cation exchange reactions,”Nat.Synth.,2022,1,626-634(“Feng 2022”).

[0266] Foerg,M.,et al.,“Moire excitons in MoSe2-WSe2heterobilayers and heterotrilayers,”Nat.Commun.,2021,12,1656(“Foerg 2021”).

[0267] Han,W.,et al.,“Phase-controllable large-area two-dimensional In2Se3and ferroelectric heterophase junction,”Nat.Nanotechnol.,2023,18,55-63(“Han 2023”).

[0268] Hellweg,S.,et al.,“Emerging approaches,challenges and opportunities in life cycle assessment,”Science,2014,344,1109-1113(“Hellweg 2014”).

[0269] Huang,Y.,et al.,“Single-crystalline 2D erucamide with low friction and enhanced thermal conductivity,”Colloids Surf.A:Physicochem.Eng.Asp.,2018,540,29-35(“Huang 2018”).

[0270] Joo,J.,et al.,“Face-selective electrostatic control of hydrothermal zinc oxide nanowire synthesis,”Nat.Mater.,2011,10,596-601(“Joo 2011”).

[0271] Jung,C.,et al.,“Highly Crystalline CVD-grown multilayer MoSe2thin film transistor for fast photodetector,”Sci.Rep.,2015,5,15313(“Jung 2015”).

[0272] Kim,K.S.,et al.,“Non-epitaxial single-crystal 2D material growth by geometric confinement,”Nature,2023,614,88-94(“Kim 2023”).

[0273] Kresse,G.,et al.,“Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set,”Phys.Rev.B,1996,54,11169-11186(“Kresse 1996”).

[0274] Larentis,S.,et al.,“Field-effect transistors and intrinsic mobility in ultra-thin MoSe2layers,”Appl.Phys.Lett.,2012,101,223104(“Larentis 2012”).

[0275] Lee,C.,et al.,“Frictional characteristics of atomically thin sheets,”Science,2010,328,76-80(“Lee 2010”).

[0276] Lee,H.A.,et al.,“Effect of Al2O3encapsulation on multilayer MoSe2thin-film transistors,”J.Phys.D:Appl.Phys.,2017,50,094001(“Lee 2017”).

[0277] Li,L.,et al.,“Kilogram-scale synthesis and functionalization of carbon dots for superior electrochemical potassium storage,”ACS Nano,2021,15,6872-6885(“Li 2021”).

[0278] Liu,Y.,et al.,“Interlayer friction and superlubricity in single-crystalline contact enabled by two-dimensional flake-wrapped atomic force microscope tips,”ACS Nano,2018,12,7638-7646(“Liu 2018”).

[0279] Luong,D.X.,et al.,“Gram-Scale Bottom-up Flash Graphene Synthesis,”Nature,2020,577,647-651(“Luong 2020”).

[0280] Monkhorst,H.J.et al.,“Special points for Brillouin-zone integrations,”Phys.Rev.B,1976,13,5188-5192(“Monkhorst 1976”)

[0281] Ogugua,C.J.,et al.,“Energy analysis of autoclave CFRP manufacturing using thermodynamics based models,”Compos.Part A:Appl.Sci.Manuf.,2023,166,107365(“Ogugua 2023”).

[0282] Perdew,J.P.,et al.,“Generalized Gradient Approximation Made Simple,”Phys.Rev.Lett.,1996,77,3865-3868(“Perdew 1996”).

[0283] Pudasaini,P.R.,et al.,“High performance top-gated multilayer WSe2field effect transistors,”Nanotechnology,2017,28,475202(“Pudasaini 2017”).

[0284] Raabe,D,“The materials science behind sustainable metals and alloys,”Chem.Rev.,2023,123,2436-2608(“Raabe 2023”).

[0285] Reuter,K.,et al.,“Composition,structure,and stability of RuO2(110)as a function of oxygen pressure,”Phys.Rev.B,2001,65,035406(“Reuter 2001”).

[0286] Shi,W.,et al.,“Reversible writing of high-mobility and high-carrier-density doping patterns in two-dimensional van der Waals heterostructures,”Nat.Electron.,2020,3,99-105(“Shi 2020”).

[0287] Si,M.,et al.,“A ferroelectric semiconductor field-effect transistor,”Nat.Electron.,2019,2,580-586(“Si 2019”).

[0288] Stanford,M.G.,et al.,“Flash Graphene Morphologies,”ACS Nano,2020,14(10),13691-13699(“Stanford 2020”).

[0289] Ubaldini,A.,et al.,“Improved chemical vapor transport growth of transition metal dichalcogenides,”J.Cryst.Growth,2014,401,878-882(“Ubaldini 2014”).

[0290] Upadhyay,S.,et al.,“Synthesis of layered 2H-MoSe2nanosheets for the high-performance supercapacitor electrode material,”J.Alloy.Compd.,2021,857,157522(“Upadhyay 2021”).

[0291] Wang,C.,et al.,“A general method to synthesize and sinter bulk ceramics in seconds,”Science,2020,368,521-526(“Wang C 2020”).

[0292] Wang,L.,et al.,“Exploring ferroelectric switching in α-In2Se3for neuromorphic computing,”Adv.Funct.Mater.,2020,30(45),2004609(“Wang L 2020”).

[0293] Wang,S.,et al.,“Two-dimensional ferroelectric channel transistors integrating ultra-fast memory and neural computing,”Nat.Commun.,2021,12,53(“Wang 2021”).

[0294] Wyss,K.M.,et al.,“Synthesis of clean hydrogen gas from waste plastic at zero net cost,”Adv.Mater.,2023,35,2306763(“Wyss 2023”).

[0295] Wyss,K.M.,et al.,“Large-scale syntheses of 2D materials:flash Joule heating and other methods,”Adv.Mater.,2022,34,2106970(“Wyss 2022”).

[0296] Yao,Y.,et al.,“Carbothermal shock synthesis of high-entropy-alloy nanoparticles,”Science,2018,359,1489-1494(“Yao 2018”).

[0297] Yu,L.,et al.,“High-performance WSe2complementary metal oxide semiconductor technology and integrated circuits,”Nano Lett.,2015,15,4928-4934(“Yu 2015”).

[0298] Zhang,X.R.,et al.,“Measurement and prediction on thermal conductivity of fused quartz,”Sci.Rep.,2020,10,6559(“Zhang 2020”).

[0299] Zheng,X.,et al.,“Hydrogen-substituted graphdiyne-assisted ultrafast sparking synthesis of metastable nanomaterials,”Nat.Nanotechnol.,2023,18,153-159(“Zheng 2023”).

[0300] Zhu,L.-F.,et al.,“Heterovalent-doping-enabled atom-displacement fluctuation leads to ultrahigh energy-storage density in AgNbO3-based multilayer capacitors,”Nat.Commun.,2023,14,1166(“Zhu L 2023”).

[0301] Zhu,W.,et al.,“Ultrafast non-equilibrium synthesis of cathode materials for Li-ion batteries,”Adv.Mater.,2023,35,2208974(“Zhu W 2023”).

Claims

1. It is a method, (a) Providing the inner raw material inside the inner container, (b) Providing an outer raw material in an outer container, wherein the inner container is located within the outer container in a flash Joule heating device. (c) A method comprising applying one or more voltage pulses, alternating current (AC), direct current (DC), or a combination thereof to the entire outer material to subject the outer material to a flash Joule heating process, wherein the flash Joule heating process on the outer material results in the conversion of the inner material to a conversion material.

2. The method according to claim 1, wherein the flash Joule heating process for the outer material provides conductive and / or radiant heating to the inner material, resulting in the conversion of the inner material into the conversion material.

3. The method according to claim 1, wherein the conversion material is a two-dimensional material.

4. Said conversion material is FeS ２ , CoS ２ , CoS ｘ Se ｙ , CoSe, NiS ２ , NiSe ２ , Cu ９ S ５ , NbSe ２ , MoSe ２ , TiSe ２ , In ２ Se ３ , SnS ２ , SnS ｘ Se ｙ , SnSe ２ , WSe ２ , WS ２ , Bi ２ S ３ , Bi ｘ S ｙ Se ｚ , Bi ２ Se ３ , TiN, LaBO ３ , Cu ２ Se, Cu ０．８７ Se, and combinations and mixtures thereof, the method according to claim 1.

5. The method according to claim 1, wherein the conversion material comprises a chalcogenide, a metal, and / or an alloy.

6. The method according to claim 1, wherein the outer raw material is selected from the group consisting of graphene, flash graphene, randomly layered graphene, anthracite, coconut shell-derived carbon, high-temperature treated biochar, activated charcoal, calcined petroleum coke, metallurgical coke, coke, shungite, carbon nanotubes, asphaltene, acetylene black, carbon black, ash, carbon fiber, graphite, and combinations and mixtures thereof.

7. The method according to claim 1, wherein the outer raw material is subjected to a flash Joule heating process by applying the voltage pulse to the entire outer raw material, and then converted into flash graphene.

8. The method according to claim 7, wherein the flash graphene is reused multiple times as the outer raw material in the method according to claim 1.

9. (a) Removing the conversion material from the inner container, (b) Providing a second inner raw material in the inner container, (c) The method according to claim 7, further comprising applying one or more voltage pulses, AC, DC, or combinations thereof to the flash graphene in the outer container to subject the flash graphene to a flash Joule heating process, wherein the flash Joule heating process on the flash graphene results in the conversion of the second inner material to a second conversion material.

10. (a) The second inner raw material is the same type of raw material as the inner raw material converted into the conversion material, (b) The method according to claim 9, wherein the second conversion material is of the same type as the first conversion material.

11. (a) The second inner raw material is a different type of raw material from the inner raw material that has been converted into the conversion material, (b) The method according to claim 9, wherein the second conversion material is of a different type from the first conversion material.

12. The method according to claim 1, wherein the step of applying one or more voltage pulses utilizes a DC voltage.

13. The method according to claim 1, wherein the step of applying one or more voltage pulses utilizes pulsed DC.

14. The method according to claim 1, wherein the step of applying one or more voltage pulses utilizes an AC voltage.

15. The method according to claim 1, wherein the step of applying one or more voltage pulses utilizes a combination of DC voltage and AC voltage.

16. (a) The step of applying one or more voltage pulses, AC, DC, or a combination thereof includes controlling the flash Joule heating process through controlled electronic modulation, (b) The method according to claim 1, wherein the controlled electronic modulation occurs through a control selected from the group consisting of variable frequency drive (VFD), pulse width modulation (PWM), proportional-integral-derivative (PID) control, ternary control, and combinations thereof.

17. The method according to claim 16, wherein the controlled electronic modulation utilizes (i) a DC current, (ii) a uniform non-progressing AC current, or (iii) a combination thereof.

18. The method according to claim 1, further comprising applying an inner container current through the inner material when applying one or more voltage pulses, AC, DC, or combinations thereof to the entire outer material.

19. It is a device, (a) an inner container that is operable to receive the inner raw material, (b) an outer container operable to receive an outer raw material, the outer container being (i) a non-conductive container operable to restrain the outer raw material, or (ii) a conductive container operable to be directly flash-joule heated, (c) an electrode operable for applying a voltage pulse, alternating current (AC), direct current (DC), or a combination thereof to the entire outer material confined within the outer container, thereby subjecting the outer material to a flash Joule heating process, wherein the flash Joule heating process on the outer material results in the conversion of the inner material to a conversion material.

20. The apparatus according to claim 19, wherein the conversion material is a two-dimensional material.

21. The aforementioned conversion material is FeS ２ CoS ２ CoS ｘ See ｙ CoSe, NiS ２ NiSe ２ ,Cd ９ S ５ NbSe ２ MoSe ２ TiSe ２ In ２ See ３ SnS ２ SnS ｘ See ｙ , SnSe ２ , WSe ２ WS ２ , Bi ２ S ３ , Bi ｘ S ｙ See ｚ , Bi ２ See ３ TiN, LaBO ３ ,Cd ２ Se, Cu ０．８７ The apparatus according to claim 19, selected from the group consisting of Se, and combinations and mixtures thereof.

22. The apparatus according to claim 19, wherein the conversion material includes a chalcogenide, a metal, and / or an alloy.

23. The apparatus according to claim 19, wherein the outer raw material is selected from the group consisting of graphene, flash graphene, randomly layered graphene, anthracite, coconut shell-derived carbon, high-temperature treated biochar, activated charcoal, calcined petroleum coke, metallurgical coke, coke, shungite, carbon nanotubes, asphaltene, acetylene black, carbon black, ash, carbon fiber, graphite, and combinations and mixtures thereof.

24. The apparatus according to claim 19, wherein the outer raw material is subjected to a flash Joule heating process by applying the voltage pulse, AC, DC, or a combination thereof to the outer raw material, and then converted into flash graphene.

25. The system further comprises a controller that controls the flash Joule heating process applied by the electrodes through controlled electronic modulation, (a) The apparatus according to claim 19, wherein the controller is selected from the group consisting of a variable frequency drive (VFD) controller, a pulse width modulation (PWM) controller, a proportional-integral-derivative (PID) control controller, a three-term control controller, and combinations thereof.

26. The apparatus according to claim 19, wherein the controlled electronic modulation operably utilizes (i) a DC current, (ii) a uniform non-progressing AC current, or (iii) a combination thereof.

27. The apparatus according to claim 19, further comprising an inner container electrode that is operable to apply an inner container current through the inner material when one or more voltage pulses, AC, DC, or combinations thereof are applied to the entire outer material.

28. It is a device, (a) an inner container that is operable to receive raw materials, (b) an outer container that can be operated to provide a protective atmosphere or vacuum to the resistance heater, (c) The resistance heater inside the outer container, (d) an electrode that is operable to supply AC or DC current to the resistor heater, (e) an apparatus comprising a plug in the inner container for containing raw materials inside.

29. (a) The inner container is a transparent inner container, (b) The resistance heater is a tubular resistance heater, (c) The resistance heater is concentric within the outer container, (c) The apparatus according to claim 28, wherein the electrode is a tubular electrode.

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