Hard carbon originated from synthetic pitch

Abstract

Producing hard carbon including reacting an aromatic hydrocarbon feed with a comonomer in the presence of a catalyst to form an isotropic pitch heating the isotropic pitch in contact with oxygen (O2) to oxidize the isotropic pitch, and heating the oxidized isotropic pitch to carbonize the oxidized isotropic pitch, thereby forming the hard carbon from the oxidized isotropic pitch. The catalyst can be or include sulfuric acid maintained in excess. The reacting of the aromatic hydrocarbon feed can be or involve a Friedel–Crafts reaction.

Description

HARD CARBON ORIGINATED FROM SYNTHETIC PITCHFIELD

[0001] Systems and methods are provided for producing hard carbon.BACKGROUND

[0002] Global demand for batteries grows. Lithium-ion batteries (LIBs) alone generally will not satisfy the battery demand due to the scarcity of lithium sources. The sodium-ion battery (SIB) is a good candidate for large-scale energy storage due to high abundant sodium sources, relatively high energy densify, and potentially low costs. In recent years, the SIB has drawn interest as a power source for large-scale grid energy storage and other applications because of advantages with the sodium abundance. Sodium is similar in physical and chemical properties as lithium but found more abundant in nature on Earth. Sodium is in seawater and constitutes 2.8% by mass of the Earth crust, and therefore can be practically characterized as a generally inexhaustible and unlimited resource. SIBs benefit from low cost, long cycle life, and room-temperature operation. SIBs have been proposed as a promising candidate for application in large-scale energy storage systems. The design of high-performance anode materials is of significance to accelerate the further development of SIBs. Conversion of heavy hydrocarbons to structured carbon materials for battery applications is relevant.SUMMARY

[0003] An aspect is method of producing hard carbon, including reacting an aromatic hydrocarbon feed with a comonomer in presence of a catalyst comprising sulfuric acid maintained in excess to form an isotropic pitch. The method includes heating the isotropic pitch in contact with oxygen (O2) to an oxidation temperature, thereby oxidizing the isotropic pitch to give an oxidized isotropic pitch. The method includes heating the oxidized isotropic pitch in an inert atmosphere to a carbonization temperature to carbonize the oxidized isotropic pitch, thereby forming the hard carbon from the oxidized isotropic pitch.

[0004] Another aspect is a method of producing hard carbon, including reacting an aromatic hydrocarbon feed with a comonomer in presence of a catalyst in a Friedel-Crafts reaction at a temperature in a temperature range of 40 °C to 350 °C to form an isotropic pitch, wherein the comonomer includes paraformaldehyde, trioxane, glyoxal, or formaldehyde, or any combinations thereof, and wherein the comonomer is in a range of 10% to 300% by weight of the aromatic hydrocarbon feed. The method includes heating the isotropic pitch under a gas that is or includes oxygen (O2) to an oxidation temperature less than 400 °C for oxidation of the isotropic pitch to give a stabilized isotropic pitch. The method includes heating the stabilized isotropic pitch underan inert gas to a carbonization temperature of at least 700 °C for carbonization of the stabilized isotropic pitch to give the hard carbon.

[0005] Yet another aspect is an amorphous carbon including hard carbon having a d(002)-spacing of at least 3.7 angstroms, wherein the amorphous carbon is formed via oxidation and carbonization of an isotropic pitch derived from an aromatic hydrocarbon feed, a comonomer, and acetic acid in a Friedel-Crafts reaction having sulfuric acid maintained in excess.

[0006] These and other features and attributes of the disclosed methods and systems of the present disclosure and their advantageous applications and / or uses will be apparent from the detailed description which follows.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] To assist those of ordinary skill in the relevant art in making and using the subj ect matter hereof, reference is made to the appended drawings, wherein:

[0008] FIG. l is a flow diagram of a technique that synthesizes isotropic pitch from hydrocarbon feed 104 and subjects the isotropic pitch to thermal treatment to give hard carbon.

[0009] FIG. 2 is a plot for thermal gravimetric analysis (TGA) curves for synthetic isotropic pitch in the Examples.

[0010] FIG. 3 is a plot for thermal gravimetric analysis (TGA) curves for synthetic isotropic pitch in the Examples.

[0011] FIG. 4 is a flow diagram of synthetic isotropic pitch shown in a tray and as heat treated in the Examples.

[0012] Tike reference numbers and designations in the various drawings indicate like elements.DETAILED DESCRIPTION

[0013] Conversion of heavy hydrocarbons to structured carbon materials for battery applications is relevant including with hard carbons found to be promising as anode materials. Hard carbons, as a promising anode, could deliver high plateau capacities at low potentials that boost the energy density of the sodium-ion battery (SIB). Hard carbon materials have attracted more attention because of their larger interlayer distance [or d(002)-spacing] than that in graphite, and their disordered atomic lattice structure, which are beneficial for sodium (Na+) insertion-extraction. In the laboratory Examples described below, hard carbon was prepared by pyrolyzing synthetic pitches fabricated from aromatic feedstock utilizing Friedel-Crafts chemistry. Embodiments may utilize a Friedel-Crafts reaction to synthesize the isotropic pitch. In the non-limiting Examples, synthetic isotropic pitches were synthesized from mixed xylenes (the three xylene isomers) with sulfuric acid (H2SO4) as a catalyst and paraformaldehyde as a comonomer. A thermal gravimetric analysis (TGA) oven study was performed in which the synthetic isotropic pitches formed weresubjected to various heat treatments including carbonization at 900 °C in the TGA oven. The structure and properties of hard carbons prepared from the synthetic isotropic pitches through solid phase oxidation were investigated.

[0014] For examples of synthetic pitch formed from hydrocarbon by chemical synthesis (e.g., acid chemistry or acid catalysis), see US Patent Application Publication No. US2024 / 0209208A1, which is incorporated by reference herein in its entirety’. For examples of mesophase pitch formed from hydrocarbons, see US Patent Application Publication No. 2024 / 0182788A1, which is incorporated by reference herein in its entirety’.

[0015] In various embodiments, systems and methods are provided for hard carbon (originated from synthetic pitch) as anode material for SIB's. Hard carbon can be formed from synthetic pitches, such as by thermally treating (e.g., pyrolyzing) the synthetic pitch. In implementations, the synthetic pitch can be fabricated from aromatic feedstock and utilizing Friedel-Crafts chemistry. Again, hard carbon materials generally have relatively large interlayer distances and disordered structure, which can be beneficial for Na+ insertion-extraction.

[0016] Embodiments include preparing hard carbon by pyrolyzing synthetic pitches, e.g., the synthetic pitches fabricated in Friedel-Crafts chemistry from aromatic feedstock. To prepare hard carbons with specific structures from the synthetic pitches, controllable synthesis strategies as reasonably designed can be beneficial. Precursors with various elemental and substance configurations result in different structures of hard carbon anodes and corresponding Na-ion storage behaviors. Considering large-scale production, highly abundant precursors of polymer, coal / pitch, and biomass materials are industrially promising and suitable for practical applications. Among these precursors, polymer-derived hard carbons show relatively high capacities and high costs, pitch / coal-derived hard carbons exhibit relatively low capacities and low costs, and biomass-derived hard carbons demonstrate moderate capacities and relatively low costs. Implementations herein not only address the synthesis of isotropic pitches from relatively low-cost hydrocarbon feeds (e.g., benzene, toluene, xylenes, naphthalene, methyl naphthalene, anthracene, phenanthrene, pyrene, Aromatic-200™ [AR-200] aromatic rings, etc.) but also address the conversion of the synthetic isotropic pitch materials into hard carbon under certain conditions. These techniques provide transforming the hydrocarbons (e.g., low-cost hydrocarbons) to structured carbon materials, e.g., for battery applications.

[0017] Generally, the two types of carbon structures are crystalline carbon (graphite) and amorphous carbon. Amorphous carbon includes soft carbon and hard carbon. Soft carbon can be transformed into graphite-like crystalline carbon after high temperature heat treatment, and is also known as graphitizable carbon. Hard carbon, on the other hand, typically cannot form orderedbut turbostratic structure with heat treatment, and is also known as non-graphitizable carbon. In implementations, hard carbon (from petroleum-based feedstocks) as anode materials can offer relatively low cost, high-rate performance, and rechargeable capability at larger current density than soft carbon / graphite. Embodiments herein include hard carbon compositions and techniques (system, method, process) of making hard carbon from hydrocarbons (e.g., low-cost hydrocarbons).

[0018] In implementations, synthetic isotropic pitches can be prepared from aromatic feedstocks, such as benzene, toluene, xylenes, naphthalenes, anthracenes, phenanthrenes, and pyrene, as well as various aromatic mix feeds from a refinery, or any combinations of these feeds. The synthesis can involve a Friedel-Crafts reaction(s). Examples of comonomer in the synthesis of the synthetic isotropic pitches include paraformaldehyde, trioxane, glyoxal, and / or formaldehyde, and the like. Glyoxal [C2H2O2 or OCHCHO] is a linear aliphatic dialdehyde containing two aldehyde groups. The aromatic feedstock can be characterized as the principal monomer. The concentration of the comonomer in the reaction mixture can be, for example, in the range of 10% to 300% by weight of the aromatic feedstock. A catalyst, such as sulfuric acid, can be employed. The catalyst may advance the synthesis reaction (e.g., including rate and / or extent of reaction) and thus promote the formation of the synthetic isotropic pitch from the aromatic feedstock and the comonomer. In addition to acting as a catalyst, the sulfuric acid (and its concentration in the reaction mixture) can also define at least in part the composition of the synthetic isotropic pitches. The concentration of sulfuric acid in the reaction mixture can be, for example, in the range of 0.1 equivalent of the aromatic feed to 10 equivalent of the aromatic feed, and in which equivalent is molar equivalent. Acetic acid may be employed as both solvent and reagent for the reaction leading to the formation of ester functional synthetic isotropic pitches. The synthetic isotropic pitches have functional groups, such as ester or alcohols, or both. The isotropic pitch formed may include an ester functional group (including multiple ester functional groups) or an alcohol functional group (including multiple alcohol functional groups), or a combination thereof.

[0019] The softening point of the isotropic pitches can be controlled, for example, by the reaction conditions, such as concentrations of the catalyst (sulfuric acid), comonomer, the aromatic hydrocarbon feed, and the solvent (e.g., acetic acid) in the synthesis reaction mixture.

[0020] Embodiments may involve a multi-step technique to form amorphous carbon. First, a step or action is to form (synthesize) isotropic pitch from an aromatic hydrocarbon feedstock (an aromatic hydrocarbon feed) and comonomer. The synthesis reaction mixture can include solvent, such as acetic acid. As discussed, the reaction mixture to form the isotropic pitch can includesulfuric acid as a catalyst. The sulfuric acid may be maintained in excess in the reaction mixture to increase the softening point of the isotropic pitch that is formed. The excess can be a molar excess, such as with respect to the aromatic hydrocarbon feedstock for the synthesis reaction. Excess sulfuric acid can give benefits in addition to increasing the softening point. For instance, in implementations, the sulfuric acid being maintained in excess can increase the reaction rate of the synthesis.

[0021] The forming (synthesizing) of the isotropic pitch from the aromatic hydrocarbon feedstock and comonomer can involve a Friedel-Crafts reaction. A Friedel-Crafts reaction generally provides for attachment of a substituent to an aromatic ring, and can proceed by electrophilic aromatic substitution. A Friedel-Crafts reaction is an organic coupling reaction involving an electrophilic aromatic substitution utilized for the attachment of substituents to aromatic rings. These reactions can involve the replacement of a hydrogen atom (initially attached to the aromatic ring) with an electrophile.

[0022] The isotropic pitch as synthesized can be subjected to thermal treatment (heat treatment) for oxidative stabilization of the isotropic pitch to stabilize dimensions during subsequent heat treatments. Then, additional thermal treatment for carbonization converts the isotropic pitch to give amorphous carbon. The oxidab on can cross-link the isotropic pitch in which polymer chains within the pitch are bonded together through covalent bonds. Oxidation introduces oxygen functionalities into the pitch, leading to formation of ether, carbonyl linkages or formation of radicals, promoting oxygen bridges via dehydrogenation or cyclization reactions. The oxidation can generate functional groups, such as ketones, aldehydes, and carboxylic acids. The kinetics and thermodynamics of these reactions can depend on the temperature, isothermal conditions, and / or the heating rate. For implementing the oxidation (oxidative stabilization), the technique may include heating the isotropic pitch to a specified temperature (an oxidation temperature) in an atmosphere including oxygen (O2) gas to form an oxidized isotropic pitch that can be a stabilized isotropic pitch. The gas can be, for instance, air or simply oxygen gas. The specified temperature can be, for example, a temperature below the softening point of the isotropic pitch. The specified temperature (for the oxidation) can be example, in the ranges of 150 °C to 400 °C, 200 °C to 350 °C, or 200 °C to 300 °C. The oxidized isotropic pitch can then be heated at a carbonization temperature (e g., in a range of from about 700 °C to about 1800 °C) to form a carbonaceous composition that is or includes amorphous carbon.

[0023] In implementations, the technique includes subjecting the isotropic pitch as stabilized (due to the oxidation) to carbonization in a furnace under an inert atmosphere (e.g.. including nitrogen gas and / or argon gas) at a carbonization temperature in carbonization temperature rangesof 700 °C to 900 °C, 900 °C to 1300 °C, 700 °C to 1500 °C, 650 °C to 1500 °C, or 700 °C to 1800 °C, and the like. This can be characterized as carbonizing the isotropic pitch at these temperatures. The carbonization refers to the removal of all (or substantially all) non-carbon components from a material under an inert atmosphere such as nitrogen or argon. Again, for the carbonization, the stabilized isotropic pitch may be heated in a furnace in an inert atmosphere. For carbonization or oxidation / stabilization. the same or similar type of furnace may be employed. The present chemistry of Friedel-Crafts reactions to form the isotropic pitch may also help to enhance the carbon yield by reducing the volatiles or reaction products released during carbonization treatments.

[0024] FIG. 1 is a technique 100 that synthesizes isotropic pitch 102 (synthetic isotropic pitch) from hydrocarbon (HC) feed 104 and subjects the isotropic pitch 102 to thermal treatment 108 (e.g., oxidation, carbonization) to give hard carbon 106. Amorphous carbon including the hard carbon 106 can be formed by first stabilizing the isotropic pitch 102 via oxidation and then carbonizing the stabilized isotropic pitch. The hydrocarbon feed 104 can ty pically be an aromatic hydrocarbon feed. The synthesis 110 to form the isotropic pitch 102 can involve a reaction mixture (e.g., in a vessel) of the hydrocarbon feed 104, comonomer, catalyst (e.g., sulfuric acid), and solvent (e g., acetic acid). The reaction temperature of the synthesis 110 (the temperature of the reaction mixture, e.g., in the vessel) can be, for example, in the ranges of 40 °C to 350 °C, 40 °C to 300 °C, or 25 °C to 350 °C. This can provide the isotropic pitch 102 with high softening point (e.g.. up to 450 °C, such as in the ranges of 300 °C to 450 °C, 325 °C to 450 °C, 350 °C to 450 °C, 375 °C to 450 °C, or 400 °C to 450 °C), as well as high purity (especially if starting with a relatively pure hydrocarbon feed 104). Any impurities can be removed during work-up. At the end of the synthesis, the product precipitates out as solids in implementations, while the solvent, comonomer, and catalyst remain in the liquid phase and can be removed, for example, by filtration. Work-up is the purification or isolating product from the reaction mixture.

[0025] The reaction mixture for the synthesis 110 can include a reaction mixture for the reacting having at least the catalyst (including sulfuric acid), the aromatic hydrocarbon feed, and the comonomer. In implementations, the reaction mixture additionally includes a performance additive(s), for example, in the range of 0.1 weight percent (wt%) to 15 wt% of the reaction mixture, to enhance material structural properties and / or enhance conductivity, energy density, etc. The reaction mixture can include a single performance additive or multiple performance additives (collectively within the given example range of 0.1 wt% to 15 wt%). Examples of performance additives are zinc, silicon, tin, aluminum, etc. Other performance additives are applicable.

[0026] As mentioned, the comonomer may be, for example, paraformaldehyde, trioxane and / or formaldehyde. The concentration of the comonomer in the synthesis 110 reaction mixture by weight of the hydrocarbon feed 104 can be, for example, in the ranges of 10% to 300%, 15% to 250%, or 20% to 200%. The concentration of the catalyst (e.g., sulfuric acid) in the reaction mixture as a molar equivalent of the feed 104 can be, for example, in the range of 0.1 equivalent to 10 equivalent, 0.3 equivalent to 9 equivalent, or 0.5 equivalent to 8 equivalent. For implementations of acetic acid as a solvent, the acetic acid can additionally be a reagent for the reaction leading, for example, to the formation of ester-functional synthetic isotropic pitch 102 (the isotropic pitch 102 having ester functional group(s)).

[0027] The synthetic isotropic pitch 102 may have functional groups, such as ester functional groups, alcohol functional groups, etc. The softening point of the isotropic pitch 102 as synthesized can be, for example, in the range of 300 °C to 450 °C, as mentioned. The softening point (Ts) is the temperature at which a given material softens. Here, for pitch materials, the softening point (Ts) is per American Society for Testing and Materials (ASTM) standard D3104-14a (2018) "‘Standard Test Method for Softening Point of Pitches (Mettler Softening Point Method)’7(last updated December 12, 2018) of ASTM International.

[0028] The softening point of the isotropic pitch 102 can be controlled, for example, by the synthesis 110 reaction conditions, such as concentration of the catalyst, comonomer, and / or solvent, and the like, in the synthesis 110 reaction mixture. In implementations, sulfuric acid is employed as the catalyst. The sulfuric acid can be maintained at an excess (e.g., molar excess with respect to the hydrocarbon feed for the synthesis 110 reaction) in the reaction mixture to increase the softening point of the isotropic pitch 102. In implementations, the sulfuric acid being maintained in excess can increase the reaction rate of the synthesis 110. Sulfuric acid is not only a catalyst for the reaction but can also define (or facilitate defining) composition of the synthetic isotropic pitch 102. The reaction conditions of the synthesis 110 may be adjusted for the molecular weight distribution and the softening point of the isotropic pitch 102. Adjusting the synthesis 110 reaction conditions, such as the molar ratio of sulfuric acid to comonomer, can facilitate controlling the molecular weight distribution and the softening point of the isotropic pitch 102. The softening point of the isotropic pitch 102 can increase with reaction time, the amount of sulfuric acid, and the amount of comonomer. This may be related to the increase in the molecular weight or molecular weight distribution.

[0029] The hydrocarbon feed 104 can include, for example, benzene, toluene, xylenes, naphthalenes, anthracenes, phenanthrenes, pyrene, as well as various aromatic mix feeds from a refinery, or any combinations thereof. The hydrocarbon feed 104 can be or include a main columnbotoms (MCB) that is generally the material that exits the botom of the main column in a fluidized catalytic cracking (FCC) unit. The hydrocarbon feed 104 can include feed (e.g., aromatic mixed feeds) from a refinery, such as MCB, slurry oil, vacuum resid, cracker botoms, or heavy residue oil. Vacuum resid or vacuum residue (VR) is a heavy substance left over after crude oil is distilled under reduced pressure, and is the heaviest part of crude oil, with components that typically have boiling points above 520 °C.

[0030] The hydrocarbon feed 104 (aromatic hydrocarbon feed) can include a single-ring aromatic compound(s) or a multi-ring aromatic compound(s), or both. Single-ring aromatic compounds are compounds having one aromatic ring. Single-ring aromatic compounds include, for example, benzene, toluene, xylene, tetralin, ethyl benzene, indene, etc. The xylene can be mixed xylenes (xylene isomers). The xylene isomers can include ortho-xylene (o-xylene). metaxylene (m-xylene), and para-xylene (p-xylene). Multi-ring aromatic compounds are compounds having multiple aromatic rings (more than one aromatic ring). For instance, a two-ring aromatic compound (e.g., naphthalenes, etc.) has two aromatic rings. A three-ring aromatic compound (e.g., phenanthrenes, etc.) has three aromatic rings. Multi-ring aromatic compounds with more than three aromatic nngs are applicable. As mentioned, the aromatic hydrocarbon feed 104 can include an aromatic mixed feed from a refinery. As indicated, the aromatic hydrocarbon feed 104 can include refinery botoms, slurry7oil, vacuum resid, cracker botoms, MCB, or heavy residue oil, or any combinations thereof.

[0031] The synthesis 110 reaction of the feed 104 into the isotropic pitch 102 can be via an acid catalyst (e.g., acetic acid, H2SO4, etc ), such as in a vessel. The synthesis 110 reaction [chemical reaction(s)] may be a chemical reaction (chemical synthesis) in which heat may be applied. The synthesis 110 reaction gives the production of the isotropic pitch 102. The yield of the isotropic pitch 102 from the feed 104 via the synthesis 110 reaction may be, for example, in the range of 90% to 99%. The synthesis 110 reaction may form water as a byproduct so the isotropic pitch 102 product may be washed with water to remove acids and the trace amounts of uncreated compounds such as unreacted hydrocarbon (e.g., xylene, etc.) and unreacted comonomer (e.g., paraformaldehyde, etc ). The synthesis 110 reaction can be characterized as acid chemistry. For the synthesis 110 reaction of the feed 104 into the isotropic pitch 102, the feed 104 can be combined (e g., in a vessel) with acid (e.g., H2SO4, acetic acid, etc.) and comonomer (e.g., paraformaldehyde) to make a reaction mixture. The mixture can then be heated to produce the isotropic pitch 102. As indicated, the mixture can be heated (e.g., in the vessel) to a temperature, for example, in the ranges of 40 °C to 300 °C. 40 °C to 350 °C. or 25 °C to 350 °C.

[0032] The isotropic pitch 102 (after being synthesized from the feed 104) may be thermally treated 108 to give amorphous carbon that includes the hard carbon 106. In particular, the isotropic pitch 102 may be subjected to the thermal treatment 108 (heat treatment), such as for oxidation (e.g., oxidative stabilization) and then higher-temperature carbonization. In implementations, the isotropic pitch 102 may be dried at ambient or moderately elevated temperature (e.g., 180 °C or less) prior to the oxidation. For instance, aheated gas (e.g., air, nitrogen, etc.) may be passed over the isotropic pitch 102, or the isotropic pitch 102 otherwise heated, to dry the isotropic pitch 102. The drying of the pitch 102 may remove or drive off solvent, unreacted hydrocarbon feed 104, unreacted comonomer, etc. The drying temperature may be, for example, in the range of 100 °C to 190 °C.

[0033] The oxidation can be oxidative (air) stabilization of the isostropic pitch 102 to increase the softening point of the isostropic pitch 102 and / or to make the isostropic pitch 102 generally infusible during the subsequent higher-temperature carbonization process. Thus, to produce hard carbon 104, the isotropic pitch 102 after any optional drying may be first stabilized (subjected to oxidative stabilization) to give the isotropic pitch as stabilized (a stabilized isotropic pitch). The oxidation (oxidative stabilization) can be performed, for example, in a vessel and / or furnace. As indicated, the oxidizing or oxidation of the isotropic pitch 102 can be, for instance, at a temperature less than the softening point of the isotropic pitch 102 or in the ranges of 200 °C to 450 °C, 200 °C to 400 °C, 200 °C to 350 °C, 200 °C to 300 °C. 250 °C to 450 °C, 250 °C to 400 °C. 250 °C to 350 °C, 300 °C to 450 °C. 300 °C to 400 °C, and the like. The isotropic pitch 102 may be heated at the temperature in an atmosphere including oxygen (e.g., in a vessel, etc.). Such thermal treatment may oxidize (e.g., stabilize) the isotropic pitch 102 giving the isotropic pitch 102 as stabilized (an oxidized and stabilized isotropic pitch) prior to the subsequent thermal (heat) treatment of carbonization. This oxidation / stabilization heat treatment prior to carbonization may involve increasing the softening point of the isotropic pitch 102, wherein increasing the softening point stabilizes the isotropic 102 pitch or at least renders the isotropic pitch 102 infusible, or both.

[0034] The stabilization may make pitch generally infusible during the subsequent carbonization process. A complete stabilization (or near complete) can refer to increasing the softening point to a level in which the pitch material stops flowing. One of the salient features of oxidative stabilization may be the kinetics of the process at different temperatures. As time proceeds, softening point increases due to changes in molecular structure or crosslinking. When the pitch material is fully stabilized, the material generally stops flowing or does not soften. The oxidation can also provide for increase in carbon yield after carbonization (see. for example, FIG 3).

[0035] The technique may include heating the oxidized isotropic pitch 102 (e.g., stabilized) at a carbonization temperature in an inert atmosphere to form a carbonaceous composition including amorphous carbon (including the hard carbon 106). The carbonization temperature can be, for example, in the ranges of 700 °C to 1800 °C, 700 °C to 1500 °C, 700 °C to 1300 °C, 700 °C to 1200 °C, 700 °C to 1100 °C, or 700 °C to 900 °C. Again, the heating for the carbonization of the isotropic pitch 102 (into the amorphous carbon including the hard carbon 106) can be performed, for instance, in a furnace in an inert atmosphere in the furnace.

[0036] The heating of the oxidized isotropic pitch for carbonization can include heating the oxidized isotropic pitich in the presence of a porosity former. In implementations, the porosity former may be incorporated with the oxidized isotropic pitch, for example, via dry blending, extrusion, and / or a mix tank (e.g.. melt belnding). The porosity former may be. for example, in the range of 0.1 wt% to 10 wt% of the combination (e.g., blend or mix) of the oxidized isotropic pitch and the porosity former. Dry blending can invove co-grinding the oxidized isotropic pitch with the porosity former(s). Melt blending may performed above the softening point of the isotropic pitch, e g., melt blending would be by extrusion or in a mix tank. A combination of both dry blending and melt blending may be utilized. For instance, a combination of first dry blend and then melt blend, e g., for increased uniformity. Porosity formers can enhance battery performance. Examples of porosity performers include zinc carbonate, calcium carbonate, potassium carbonate, magnesium chloride, etc. A porosity former is a substance that creates porosity in a material by introducing empty space. Porosity is the percentage of empty space within a material.

[0037] A porosity former for hard carbon can be a material added during the synthesis process that helps create pores within the hard carbon structure, typically by decomposing or volatilizing during carbonization, leaving behind empty spaces that contribute to the desired porosity for applications like sodium-ion batteries, for example, where high pore volume is beneficial, as it will create more solid electrolyte interphase (SEI) and cause lower initial Coulombic efficiency (ICE). Examples include polyvinyl butyral (PVB) or other organic compounds (e.g., volatile organic compounds) that can be incorporated into the precursor material before pyrolysis to promote generating the pore network within the hard carbon. Use of the porosity former can generate controlled pore sizes and distributions within the hard carbon structure by decomposing and releasing gases during carbonization. In implementations, the porosity former can facilitate forming of closed pores within the hard carbon, which are generally beneficial for sodium ion storage. The choice of porosity former can depend on the desired pore size, the carbonization temperature, the desired application, and other factors. PVB decomposes at relatively high temperatures, leaving behind spaces (micropores) within the carbon matrix. Certain polymershaving volatile functional groups that vaporize during carbonization can be utilized to create pores.

[0038] An embodiment is a method of producing hard carbon. In implementations, the method can start with reacting (e.g., in a Friedel-Craft reaction at a reaction temperature in a range of 40 °C to 350 °C) an aromatic hydrocarbon feed (e.g., including single-ring aromatic compounds and / or a multi-aromatic compounds) with a comonomer (e.g., paraformaldehyde, trioxane, glyoxal, and / or formaledyde) in the presence of a catalyst (e.g., the catalyst at less than 10 equivalent of the aromatic hydrocarbon feed, such as in the range of 1.0 molar equivalent to 10 molar equivalent) to form an isotropic pitch. The catalyst includes sulfuric acid maintained in excess. The maintaining of the sulfuric acid in excess can increase the softening point of the isotropic pitch. The aromatic hydrocarbon feed can include xylene isomers. The aromatic hydrocarbon feed can include an aromatic mixed feed from a refinery. As discussed, the aromatic hydrocarbon feed can include benzene, toluene, xylene, naphthalene, anthracene, phenanthrene, pyrene, an aromatic mixed feed from a refinery, main column bottoms (MCB), refinery bottoms, slurry oil, vacuum resid, cracker bottoms, MCB, or heavy residue oil, or any combinations thereof.

[0039] The comonomer may be, for example, in the range of 10% to 300% by weight of the aromatic hydrocarbon feed. The reacting of the aromatic hydrocarbon feed with the comonomer in the presence of the catalyst can also be in presence of a solvent, such as acetic acid, wherein the acetic acid further is a reagent giving formation of ester functional group(s) in isotropic pitch. The reaction mixture for the reacting to form the isotropic pitch can includes at least the aromatic hydrocarbon feed, the comonomer, and the catalyst including sulfuric acid. In implementations, the reaction mixture includes a performance additive. The performance additive can be, for example, in the ranges of 0.1 wt% to 15 wt% of the reaction mixture or 1 wt% to 15 wt% of the reaction mixture.

[0040] The formed isotropic pitch is heated in contact with oxygen (O2), such as in atmosphere including air or oxygen gas, to an oxidation temperature, thereby oxidizing the isotropic pitch to give an oxidized isotropic pitch. In implementations, the isotropic pitch can be heated in the presence of a porosity former. The oxidation temperature can be, for example less than a softening point of the isotropic pitch and / or in the oxidation temperature range of 200 °C to 400 °C. The oxidizing of the isotropic pitch can give the oxidized isotropic pitch as stabilized and thereby infusible. The method can include heating the isotropic pitch (prior to oxidizing the isotropic pitch) to a dry ing temperature less than the oxidation temperature, thereby drying the isotropic pitch.

[0041] The method includes heating the oxidized isotropic pitch in an inert atmosphere (e.g., including N2 and / or argon gas) to a carbonization temperature (e.g., in a range of 700 °C to 1500°C) to carbonize the oxidized isotropic pitch, thereby forming the hard carbon from the oxidized isotropic pitch. The forming of the hard carbon can involve forming an amorphous carbon including the hard carbon.

[0042] Another embodiment is a method of producing hard carbon, including reacting an aromatic hydrocarbon feed with a comonomer in presence of a catalyst (e.g., sulfuric acid) in a Friedel-Crafts reaction at a temperature in a temperature range of 40 °C to 350 °C to form an isotropic pitch, wherein the comonomer includes paraformaldehyde, trioxane, or formaldehyde, or any combinations thereof. The reaction mixture can include solvent (e.g., acetic acid) in addition to the the aromatic hydrocarbon feed, the comonomer, and the catalyst. The method can include controlling a softening point of the isotropic pitch by adj usting concentration of at least one of the comonomer, the catalyst, or the solvent in the reaction mixture. The method can include maintaining the sulfuric acid in excess in the reaction mixture, wherein the sulfuric acid is less than 10 equivalent (molar equivalent) of the aromatic hydrocarbon feed. The aromatic hydrocarbon feed can include, for example, at least one of benzene, toluene, xylene, naphthalene, anthracene, phenanthrene, pyrene, or an aromatic mixed feed from a refinery. The method includes heating the isotropic pitch under a gas including O2 to an oxidation temperature less than 400 °C for oxidation of the isotropic pitch to give a stabilized isotropic pitch, and heating the stabilized isotropic pitch under an inert gas (e.g., N2 gas or argon gas) to a carbonization temperature of at least 700 °C for carbonization of the stabilized isotropic pitch to give the hard carbon.

[0043] Yet another embodiment is an amorphous carbon that includes hard carbon having a d(002)-spacing of at least 3.7 angstroms, such as in the ranges of 3.7 angstroms to 3.85 angstroms, 3.7 angstroms to 3.8 angstroms, or 3.72 angstroms to 3.78 angstroms, or at least 3.72 angstroms, such as in the ranges of 3.72 angstroms to 3.85 angstroms, 3.72 angstroms to 3.8 angstroms, or 3.72 angstroms to 3.78 angstroms. The amorphous carbon is formed via oxidation and carbonization of an isotropic pitch (e.g., having an ester functional group) derived from an aromatic hydrocarbon feed, a comonomer (e.g., trioxane, paraformaldehyde, or formaldehyde, and acetic acid in a Friedel-Crafts reaction having sulfuric acid maintained in excess. In implementations, the aromatic hydrocarbon feed includes benzene, toluene, xylene, naphthalene, anthracene, phenanthrene, or pyrene, or any combinations thereof.

[0044] Accordingly, the present disclosure may provide for forming and processing isotropic pitch to give hard carbon. The methods, systems, and compositions may include any of the various features disclosed herein, including one or more of the following statements.

[0045] Embodiment 1. A method of producing hard carbon, comprising: reacting an aromatic hydrocarbon feed with a comonomer in presence of a catalyst comprising sulfuric acid maintainedin excess to form an isotropic pitch; heating the isotropic pitch in contact with oxygen (O2) to an oxidation temperature, thereby oxidizing the isotropic pitch to give an oxidized isotropic pitch; and heating the oxidized isotropic pitch in an inert atmosphere to a carbonization temperature to carbonize the oxidized isotropic pitch, thereby forming the hard carbon from the oxidized isotropic pitch.

[0046] Embodiment 2. The method of Embodiment 1, wherein a reaction mixture for the reacting comprises the aromatic hydrocarbon feed, the comonomer, a performance additive, and the catalyst comprising sulfuric acid, and wherein the performance additive is in a range of 0.1 weight percent (wt%) to 15 wt% of the reaction mixture.

[0047] Embodiment 3. The method of Embodiment 2, wherein the performance additive comprises zinc, silicon, tin, or aluminum, or any combination thereof, and wherein the aromatic hydrocarbon feed comprises an aromatic mixed feed from a refinery.

[0048] Embodiment 4. The method of any preceding Embodiment, wherein heating the oxidized isotropic pitch comprises heating the oxidized isotropic pitch in presence of a porosity former, and wherein the aromatic hydrocarbon feed comprises benzene, toluene, xylene, naphthalene, anthracene, phenanthrene, pyrene, an aromatic mixed feed from a refinery, main column bottoms (MCB), refinery bottoms, slurry oil, vacuum resid, cracker bottoms, or heavy residue oil, or any combinations thereof.

[0049] Embodiment 5. The method of Embodiment 4, wherein the porosity former is in a range of 0.1 wt% to 10 wt% of a combination of the oxidized isotropic pitch and the porosity former.

[0050] Embodiment 6. The method of any preceding Embodiment, wherein the catalyst is less than 10 equivalent of the aromatic hydrocarbon feed, wherein maintaining the sulfuric acid in excess increases a softening point of the isotropic pitch, and wherein the aromatic hydrocarbon feed comprises a single-ring aromatic compound or a multi-aromatic compound, or both.

[0051] Embodiment 7. The method of any preceding Embodiment, wherein the reacting the aromatic hydrocarbon feed with the comonomer in the presence of the catalyst comprising the sulfuric acid is performed at a reaction temperature in a reaction temperature range of 40 °C to 350 °C, and wherein the comonomer is in a range of 10% to 300% by weight of the aromatic hydrocarbon feed.

[0052] Embodiment 8. The method of any preceding Embodiment, wherein the comonomer comprises paraformaldehyde, trioxane, glyoxal, or formaledyde, or any combinations thereof, wherein the oxidation temperature is less than a softening point of the isotropic pitch, wherein the inert atmosphere comprises at least one of nitrogen (N2) gas or argon gas, and wherein the forming the hard carbon comprises forming an amorphous carbon comprising the hard carbon.

[0053] Embodiment 9. The method of any preceding Embodiment, wherein the reacting comprises a Friedel-Craft reaction, wherein the oxidation temperature is in an oxidation temperature range of 200 °C to 400 °C, wherein oxidizing the isotropic pitch gives the oxidized isotropic pitch as stabilized and thereby infusible, and wherein the carbonization temperature is in a carbonization temperature range of 700 °C to 1500 °C.

[0054] Embodiment 10. The method of any preceding Embodiment, comprising heating the isotropic pitch prior to oxidizing the isotropic pitch to a drying temperature less than the oxidation temperature, thereby drying the isotropic pitch, and wherein the aromatic hydrocarbon feed comprises xylene isomers.

[0055] Embodiment 11. The method of any preceding Embodiment, wherein the reacting the aromatic hydrocarbon feed with the comonomer is in the presence of the catalyst and a solvent, wherein the solvent comprises acetic acid, and wherein the acetic acid further is a reagent giving formation of an ester functional group in the isotropic pitch.

[0056] Embodiment 12. A method of producing hard carbon, comprising: reacting an aromatic hydrocarbon feed with a comonomer in presence of a catalyst in a Friedel-Crafts reaction at a temperature in a temperature range of 40 °C to 350 °C to form an isotropic pitch, wherein the comonomer comprises paraformaldehyde, trioxane, glyoxal, or formaldehyde, or any combinations thereof, and wherein the comonomer is in a range of 10% to 300% by weight of the aromatic hydrocarbon feed; heating the isotropic pitch under a gas comprising oxygen (O2) to an oxidation temperature less than 400 °C for oxidation of the isotropic pitch to give a stabilized isotropic pitch; and heating the stabilized isotropic pitch under an inert gas to a carbonization temperature of at least 700 °C for carbonization of the stabilized isotropic pitch to give the hard carbon.

[0057] Embodiment 13. The method of Embodiment 12, comprising a solvent in a reaction mixture for the reacting, the reaction mixture comprising the aromatic hydrocarbon feed, the comonomer, the catalyst, and the solvent, and wherein the catalyst comprises sulfuric acid.

[0058] Embodiment 14. The method of Embodiment 13, comprising controlling a softening point of the isotropic pitch by adjusting concentration of at least one of the comonomer, the catalyst, or the solvent in the reaction mixture, wherein the solvent comprises acetic acid.

[0059] Embodiment 15. The method of Embodiment 13 or Embodiment 14, comprising maintaining the sulfuric acid in excess in the reaction mixture, wherein the sulfuric acid is less than 10 equivalent of the aromatic hydrocarbon feed.

[0060] Embodiment 16. The method of any one of Embodiments 12 to 15, wherein the aromatic hydrocarbon feed comprises at least one of benzene, toluene, xylene, naphthalene, anthracene, phenanthrene, pyrene, an aromatic mixed feed from a refinery, main column bottoms (MCB), refinery bottoms, slurry oil, vacuum resid, cracker bottoms, or heavy residue oil, and wherein the inert gas comprises nitrogen (N2) gas or argon gas.

[0061] Embodiment 17. An amorphous carbon comprising hard carbon comprising a d(002)-spacing of at least 3.7 angstroms, wherein the amorphous carbon is formed via oxidation and carbonization of an isotropic pitch derived from an aromatic hydrocarbon feed, a comonomer, and acetic acid in a Friedel-Crafts reaction having sulfuric acid maintained in excess.

[0062] Embodiment 18. The amorphous carbon of Embodiment 17, wherein the aromatic hydrocarbon feed comprises benzene, toluene, xylene, naphthalene, anthracene, phenanthrene, or pyrene, or any combinations thereof.

[0063] Embodiment 19. The amorphous carbon of Embodiment 17 or Embodiment 18, wherein the comonomer comprises trioxane, paraformaldehyde, or formaldehyde, glyoxal, or any combinations thereof.

[0064] Embodiment 20. The amorphous carbon of any one of Embodiments 17 to 19, wherein the isotropic pitch comprises an ester functional group or an alcohol functional group, or a combination thereof.

[0065] To facilitate a better understanding of the present invention, the following examples of certain aspects of some embodiments are given. In no way should the following examples be read to limit, or define, the entire scope of the disclosure.

[0066] While the disclosure has been described with respect to a number of embodiments and examples, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope and spirit of the disclosure as disclosed herein. Although individual embodiments are discussed, the present disclosure covers all combinations of all those embodiments.

[0067] While compositions, methods, and processes are described herein in terms of “comprising,” “containing,” “having,” or “including” various components or steps, the compositions and methods can also “consist essentially of’ or “consist of’ the various components and steps. The phrases, unless otherwise specified, “consists essentially of’ and “consisting essentially of’ do not exclude the presence of other steps, elements, or materials, whether or not, specifically mentioned in this specification, so long as such steps, elements, or materials, do not affect the basic and novel characteristics of the disclosure, additionally, they do not exclude impurities and variances normally associated with the elements and materials used.

[0068] All numerical values within the detailed description are modified by “about’' the indicated value, and take into account experimental error and variations that would be expected by a person having ordinary skill in the art.

[0069] Many alterations, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description without departing from the spirit or scope of the present disclosure and that when numerical lower limits and numerical upper limits are listed herein, ranges from any lower limit to any upper limit are contemplated.

[0070] Examples

[0071] The Examples are not meant to limit the present techniques.

[0072] Synthetic isotropic pitch

[0073] Synthetic isotropic pitches were synthesized from mixed xylenes using various concentrations of sulfuric acid. The synthetic isotropic pitches had high softening point, as well as various functional groups. This synthesis is represented by Scheme 1 below that depicts mixed xylenes as hydrocarbon feed on the left and synthetic isotropic pitch as product on the right. For the synthesis, xylenes (the three xylene isomers) and paraformaldehyde were briefly mixed in acetic acid in an a round bottom flask. Sulfuric acid was added dropwise to the flask. The resulting mixture was stirred at 90 °C for 4 hour (h), and then cooled to ambient temperature and poured into water. The precipitates were filtered and washed with water and dried under vacuum at 50 °C, or 180 °C under inert gas flow, yielding 95% as a gray solid.Paraformaldehyde Sulfuric acidAcetic acidScheme 1. Synthesis of isotropic pitches in acetic acid.

[0074] Table 1 gives results showing five isotropic pitches (IP-1, IP-2, IP-3, IP-4, IP-5) formed in five respective syntheses. The softening point for each of the five isotropic pitches was greater than 400 °C. For the syntheses, the xylenes is denoted as a 100 weight percent (wt%) basis, with the comonomer paraformaldehyde and the catalyst sulfuric acid each given in wt% based on the xylenes.Table 1. Xylenes isotropic pitch samples prepared with sulfuric acid at 90 °C for 4 h.Isotropic Xylene Paraformaldehyde Sulfuric acid Ts(°C) pitch (wt%) (wt%) (wt%)IP-1 100 42.5 900 >400IP-2 100 42.5 450 >400IP-3 100 42.5 225 >400IP-4 100 42.5 225 >400IP-5 100 42.5 184 >400IP-6 100 42.5 140 >400

[0075] Cross-linking of pitches via TGA

[0076] The synthetic isotropic pitches were cross-linked by air oxidation (250 °C, 2h. 0.5 °C / minute) in a thermal gravimetric analysis (TGA) oven. The synthetic isotropic pitches were then subjected to carbonization at 900 °C in the TGA oven.

[0077] FIG. 2 is a plot 200 (for TGA curves) of weight percent 202 over temperature 204 in °C. The plot 200 depicts weight (mass) loss, as indicated by the weight percent 202, versus temperature 204 for TGA. The curve 206 and the curve 208 can each be labeled as a TGA curve.

[0078] For curve 206, the TGA procedure involved placing synthetic isotropic pitch [IP-5] in the TGA oven, selecting air as the gas in the TGA oven, and allowing the TGA oven and the synthetic isotropic pitch to equilibrate at 30 °C. The temperature was then ramped at 10 °C per minute (°C / min) to 180 °C. The ramp to 180 °C generally dried the pitch in removing, for example, any residual solvent or unreacted components. Next, the temperature was ramped at 0.5 °C / min to 250 °C and maintained isothermal at 250 °C for 120 minutes for oxidation of the synthetic isotropic pitch via the presence of the oxygen gas in the selected air gas. The TGA procedure then included selecting nitrogen as the gas in the TGA oven and maintaining the temperature isothermal at 250 °C for 10 minutes to replace air in the TGA oven with nitrogen. The temperature was ramped at 20 °C / min to 900 °C, allowing for carbonization of the oxidized synthetic isotropic pitch to occur. As indicated in FIG. 2 for curve 206, the weight (mass) of the synthetic isotropic pitch decreased to 63 wt% of the initial 100 wt%.

[0079] For curve 208, the TGA procedure involved placing synthetic isotropic pitch [IP-5] in the TGA oven, selecting nitrogen as the gas in the TGA oven, and allowing the TGA oven and the synthetic isotropic pitch to equilibrate at 30 °C. The temperature was then ramped at 20 °C / min to 900 °C, allowing for carbonization of the synthetic isotropic pitch. No oxidation was performed. As indicated in FIG. 2 for curve 208, the weight (mass) of the synthetic isotropic pitch decreased to 29 wt% of the initial 100 wt%.

[0080] FIG. 3 is a plot 300 of weight percent 302 over temperature 304 in °C for heat treatment of synthetic isotropic pitch in a TGA oven. The plot 300 depicts weight (mass) loss, as indicated by the weight percent 302, versus temperature 304 for the TGA. The curves 306, 308, 310 are TGA curves for the TGA data.

[0081] For curve 306, the TGA procedure was similar as with the curve 206 of FIG. 2, except the oxidation was performed at 260 °C instead of 250 °C. For the curve 306, the TGA oven having synthetic isotropic pitch [IP-5] and air as the gas was ramped to 260 °C for oxidation, and then ramped to 900 °C but with nitrogen as the gas for carbonization.

[0082] For cune 308, the TGA procedure was similar as with the curve 208 of FIG. 2. For the curve 308, the TGA oven having synthetic isotropic pitch [IP-5] and nitrogen as the gas was ramped to 900 °C for carbonization. No oxidation was performed. For curve 310, the the TGA oven having synthetic isotropic pitch [IP-5] and air as the gas was ramped to 900 °C.

[0083] FIG. 4 is an example of a flow diagram 400 of synthetic isotropic pitch in alumina sample tray and as heat treated in a tube furnace. The synthetic isotropic pitch 402 prior to heat treatment was a moist powder having a color that was off-white or light yellow. The isotropic pitch 402 was heated to 180 °C in air to give dried isotropic pitch 404. In the drying, any residual solvent, hydrocarbon, and comonomer were driven off. The dried isotropic pitch 404 was chunks of material having a brown color. For oxidation (low-temperature oxidation), the dried isotropic pitch 404 was heated in air to 250 °C and consolidated into a hard porous block. Post oxidation pulverizing gave the oxidized (stabilized) isotropic pitch 406 as smaller chunks or particles and having a dark brown color. For carbonization, the oxidized isotropic pitch 406 was heated in nitrogen gas to 900 °C to give carbonized isotropic pitch 408 that is similar size chunks or particles as the depicted oxidized isotropic pitch 406 but with a dark gray color.

[0084] Table 2 below gives d(002)-spacing given in angstroms (A) as determined by X-ray diffraction for hard carbons made from synthetic isotropic pitch in the Examples at various heat treatments. A sample number (#) and heat treatment are given. The two theta (20) angle of the X-ray diffraction is given in degrees. The source of sample 1 is IP-5 received as prepared above. Samples 2, 3, 4, 5, 6, and 7 are based on sample 1. The X-ray diffraction analysis was applied to all samples shown in Table 2, which includes pitch samples and amorphous carbon samples, but does not include soft carbon samples.Table 2. d(002)-spacing determined by X-ray diffraction for hard carbons made from synthetic isotropic pitch at various heat treatments. _ _ _# Heat treatment 20 (deg) d(002) (A)1 IP-5 as prepared 20.967 4.23342 0.5 °C / min from ambient to 260 °C, hold 2hr, in air 19.250 4.60703 900 °C, no hold, in N2 23.169 3.83584 900 °C, hold 2hr, in N2 25.585 3.47885 1100 °C, hold 2hr, in N2 25.389 3.50536 1300 °C, hold 2hr, in N2 25.615 3.47497 1500 °C, hold 2hr, in N2 25.792 3.45148 Oxidation at 250 °C in TGA oven and then carbonize at 23.638 3.7608900 °C by heating 20 °C / min under N2, no hold.

[0085] As indicated in Table 2, the hard carbon samples derived from synthetic isotropic pitch generally show d(002)-spacing larger than that in graphite, which has d(002) = 3.354 A. Furthermore, Table 2 is also an example in which the the d(002)-spacing of hard carbon can be controlled by varying carbonization temperature and carbonization hold time. As an example, it is noted that the d(002)-spacing of carbonized synthetic isotropic pitch samples decreases with increasing carbonization temperatures from 900 °C to 1500 °C. all held for 2 hours. As a further example, it is noted that the d(002)-spacing of synthetic isotropic pitch samples carbonized at 900 °C increases with shorter hold time decreasing from 2 hours to 0 hour (no hold time).

Claims

CLAIMS;1. A method of producing hard carbon, comprising:reacting an aromatic hydrocarbon feed with a comonomer in presence of a catalyst comprising sulfuric acid maintained in excess to form an isotropic pitch;heating the isotropic pitch in contact with oxygen (O2) to an oxidation temperature, thereby oxidizing the isotropic pitch to give an oxidized isotropic pitch; andheating the oxidized isotropic pitch in an inert atmosphere to a carbonization temperature to carbonize the oxidized isotropic pitch, thereby forming the hard carbon from the oxidized isotropic pitch.

2. The method of claim 1, wherein a reaction mixture for the reacting comprises the aromatic hydrocarbon feed, the comonomer, a performance additive, and the catalyst comprising sulfuric acid, and wherein the performance additive is in a range of 0.1 weight percent (wt%) to 15 wt% of the reaction mixture.

3. The method of claim 2, wherein the performance additive comprises zinc, silicon, tin, or aluminum, or any combination thereof, and wherein the aromatic hydrocarbon feed comprises an aromatic mixed feed from a refinery'.

4. The method of any preceding claim, wherein heating the oxidized isotropic pitch comprises heating the oxidized isotropic pitch in presence of a porosity former, and wherein the aromatic hydrocarbon feed comprises benzene, toluene, xylene, naphthalene, anthracene, phenanthrene, pyrene, an aromatic mixed feed from a refinery, main column bottoms (MCB), refinery bottoms, slurry’ oil, vacuum resid, cracker bottoms, or heavy residue oil, or any combinations thereof.

5. The method of claim 4, wherein the porosity' former is in a range of 0.1 wt% to 10 wt% of a combination of the oxidized isotropic pitch and the porosity former.

6. The method of any preceding claim, wherein the catalyst is less than 10 equivalent of the aromatic hydrocarbon feed, wherein maintaining the sulfuric acid in excess increases a softening point of the isotropic pitch, and wherein the aromatic hydrocarbon feed comprises a single-ring aromatic compound or a multi-aromatic compound, or both.

7. The method of any preceding claim, wherein the reacting the aromatic hydrocarbon feed with the comonomer in the presence of the catalyst comprising the sulfuric acid is performed at a reaction temperature in a reaction temperature range of 40 °C to 350 °C, and wherein the comonomer is in a range of 10% to 300% by weight of the aromatic hydrocarbon feed.

8. The method of any preceding claim, wherein the comonomer comprises paraformaldehyde, trioxane, glyoxal, or formaldehyde, or any combinations thereof, wherein the oxidation temperature is less than a softening point of the isotropic pitch, wherein the inert atmosphere comprises at least one of nitrogen (N2) gas or argon gas, and wherein the forming the hard carbon comprises forming an amorphous carbon comprising the hard carbon.

9. The method of any preceding claim, wherein the reacting comprises a Friedel-Craft reaction, wherein the oxidation temperature is in an oxidation temperature range of 200 °C to 400 °C, wherein oxidizing the isotropic pitch gives the oxidized isotropic pitch as stabilized and thereby infusible, and wherein the carbonization temperature is in a carbonization temperature range of 700 °C to 1500 °C.

10. The method of any preceding claim, comprising heating the isotropic pitch prior to oxidizing the isotropic pitch to a d ing temperature less than the oxidation temperature, thereby drying the isotropic pitch, and wherein the aromatic hydrocarbon feed comprises xylene isomers.

11. The method of any preceding claim, wherein the reacting the aromatic hydrocarbon feed with the comonomer is in the presence of the catalyst and a solvent, wherein the solvent comprises acetic acid, and wherein the acetic acid further is a reagent giving formation of an ester functional group in the isotropic pitch.

12. A method of producing hard carbon, comprising:reacting an aromatic hydrocarbon feed with a comonomer in presence of a catalyst in a Friedel-Crafts reaction at a temperature in a temperature range of 40 °C to 350 °C to form an isotropic pitch, wherein the comonomer comprises paraformaldehyde, trioxane, glyoxal, or formaldehyde, or any combinations thereof, and wherein the comonomer is in a range of 10% to 300% by weight of the aromatic hydrocarbon feed;heating the isotropic pitch under a gas comprising oxygen (O2) to an oxidation temperature less than 400 °C for oxidation of the isotropic pitch to give a stabilized isotropic pitch; andheating the stabilized isotropic pitch under an inert gas to a carbonization temperature of at least 700 °C for carbonization of the stabilized isotropic pitch to give the hard carbon.

13. The method of claim 12, comprising a solvent in a reaction mixture for the reacting, the reaction mixture comprising the aromatic hydrocarbon feed, the comonomer, the catalyst, and the solvent, and wherein the catalyst comprises sulfuric acid.

14. The method of claim 13, comprising controlling a softening point of the isotropic pitch by adjusting concentration of at least one of the comonomer, the catalyst, or the solvent in the reaction mixture, wherein the solvent comprises acetic acid.

15. The method of claim 13 or claim 14, comprising maintaining the sulfuric acid in excess in the reaction mixture, wherein the sulfuric acid is less than 10 equivalent of the aromatic hydrocarbon feed.

16. The method of any one of claims 12 to 15, wherein the aromatic hydrocarbon feed comprises at least one of benzene, toluene, xylene, naphthalene, anthracene, phenanthrene, pyrene, an aromatic mixed feed from a refinery', main column bottoms (MCB), refinery bottoms, slurry' oil, vacuum resid, cracker bottoms, or heavy residue oil, and wherein the inert gas comprises nitrogen (N2) gas or argon gas.

17. An amorphous carbon comprising:hard carbon comprising a d(002)-spacing of at least 3.7 angstroms; andwherein the amorphous carbon is formed via oxidation and carbonization of an isotropic pitch derived from an aromatic hydrocarbon feed, a comonomer, and acetic acid in a Friedel-Crafts reaction having sulfuric acid maintained in excess.

18. The amorphous carbon of claim 17, wherein the aromatic hydrocarbon feed comprises benzene, toluene, xylene, naphthalene, anthracene, phenanthrene, or pyrene, or any combinations thereof.

19. The amorphous carbon of claim 17 or claim 18. wherein the comonomer comprises trioxane, paraformaldehyde, or formaldehyde, glyoxal, or any combinations thereof.

20. The amorphous carbon of any one of claims 17 to 19, wherein the isotropic pitch comprises an ester functional group or an alcohol functional group, or a combination thereof.

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