DESC:METHOD FOR SYNTHESIZING HIGHLY GRAPHITIZED POROUS CARBON FOR BATTERY ANODE
PRIORITY STATEMENT
The present application claims priority under Section 11 of the Indian Patents Act, 1970 (as amended) to Indian patent application number 202341037490 filed on 31 May 2023, the entire contents of which are incorporated herein by reference.
FIELD
The present disclosure relates generally to the manufacturing of electrodes used in electrochemical cells. More particularly the present disclosure relates to graphitized porous carbon electrode used as an anode of an electrochemical cell.
BACKGROUND
The anode material in a lithium-ion cell plays a pivotal role in determining its overall performance. Among the various anode materials, graphite has emerged as the most widely used material in commercial lithium-ion batteries (LIBs). This popularity is attributed to its favorable combination of properties, including high lithium-ion capacity, good stability over extended charge-discharge cycles, and low production costs. Graphite's relatively high lithium storage capacity enables it to store a substantial number of lithium ions during charging, which is critical for achieving higher energy densities in batteries.

One of graphite's standout characteristics is its excellent stability during repeated charge and discharge cycles. It can reversibly intercalate and de-intercalate lithium ions with minimal structural degradation, resulting in prolonged battery life. This structural robustness also helps in preventing undesirable side reactions or compound formations that could lead to irreversible capacity loss, thereby enhancing the cycle life of the battery. Graphite's relatively high electrical conductivity further complements its electrochemical performance by facilitating efficient electron transfer during charging and discharging, reducing internal resistance, and maintaining consistent energy output. Additionally, graphite exhibits good thermal stability, making it safer to use by reducing the risk of thermal runaway, a common safety concern in high-energy batteries.

Consistency in material properties is essential for ensuring reliable battery performance and optimizing manufacturing processes. Synthetic graphite is therefore often preferred over natural graphite as an anode material in LIBs. Synthetic graphite is produced through a controlled manufacturing process, allowing for precise control over its properties and composition. This controlled synthesis results in a material that is more uniform and consistent compared to natural graphite, which often suffers from variability in quality and impurity levels. Furthermore, synthetic graphite typically exhibits superior electrochemical performance, including higher specific capacity, improved cyclability, and better rate capability. These advantages make it particularly suitable for applications that demand rapid charging, high power output, and long operational lifespans. The manufacturing process of synthetic graphite also allows customization of its properties to meet specific battery requirements. Adjustments to particle size, morphology, and surface characteristics can significantly enhance electrochemical properties such as lithium-ion diffusion kinetics and electrode polarization.

The production of synthetic graphite often involves carbonization of organic substrates, where the organic material is heated to high temperatures in an inert atmosphere to remove volatile components, leaving behind carbon-rich material. Graphite precursors, such as hard carbon and soft carbon, present distinct challenges. Hard carbon's cross-linked and disordered structure limits its lithium-ion storage capacity and introduces significant irreversible capacity loss during the initial charge-discharge cycles. It also exhibits a large voltage hysteresis, which reduces its efficiency. In contrast, soft carbon, synthesized at higher temperatures (typically above 2000°C), achieves higher electrical conductivity and a more ordered structure. However, this comes at the cost of increased energy consumption, making the process less environmentally sustainable.

Catalytic graphitization has emerged as a promising alternative for synthesizing nanostructured graphitic carbons. This process involves transforming non-graphitic carbon into graphite through heat treatment in the presence of catalytic agents, typically transition metals such as iron. Catalytic graphitization offers significant advantages, including lower process temperatures compared to non-catalytic methods, making it more energy-efficient and environmentally friendly. Iron, in particular, is an attractive catalyst due to its abundance, low cost, and low toxicity. Research by Hunter et al. (Hunter, R. D.; Ramírez-Rico, J.; Schnepp, Z. Iron-Catalyzed Graphitization for the Synthesis of Nanostructured Graphitic Carbons. School of Chemistry, University of Birmingham, Birmingham, Dpto. Fisica de la Materia Condensada and Instituto de Ciencia de Materiales de Sevilla, Universidad de Sevilla-CSIC, 41092 Sevilla, Spain, Published on 7th February 2022). has demonstrated the potential of iron-catalyzed graphitization for producing nanostructured graphitic carbons.

Earlier works by Sevilla et al. (M. Sevilla, C. Sanchís, T. Valdés-Solís, E. Morallón, A.B. Fuertes, Direct synthesis of graphitic carbon nanostructures from saccharides and their use as electrocatalytic supports, Carbon, Volume 46, Issue 6, 2008, Pages 931-939) explored methods for synthesizing graphitic carbon nanostructures (GCNs) using saccharides as precursors. These methods involve impregnating saccharides with nickel or iron nitrates, subjecting them to heat treatment in an inert nitrogen atmosphere at temperatures ranging from 900°C to 1000°C, and selectively recovering graphitic carbon through liquid-phase oxidation. Another approach utilized high loadings of metal salts as both graphitization catalysts and templates for pore creation in a one-step synthetic method for fabricating graphitic mesoporous carbon. However, these methods have significant drawbacks. A considerable amount of nitrogen oxides (NOx) is released during the graphitization process, contributing to environmental pollution and causing damage to laboratory equipment.

Given the environmental and operational challenges associated with existing methods, there is a critical need for an improved process to produce porous graphitized carbon anodes. Such a method should minimize or eliminate the release of harmful gases, particularly nitrogen oxides, to reduce environmental impact while ensuring high-quality graphitized anodes. The present invention addresses these challenges by disclosing an alternative manufacturing method that overcomes the limitations of current techniques, offering a sustainable and efficient solution for producing porous graphitized carbon anodes.
OBJECT OF THE INVENTION
It has already been proposed that the reduction of ferric nitrate during the catalytic graphitization of carbon precursors results in the emission of Nitrate gas, which is not ideal or unfavorable for the environment.
The primary object of the present invention is a method for producing highly graphitized porous carbon (HGPC) from the effective reduction of Ferric nitrate using organic precursor without polluting the atmosphere with Nitrogen oxide.
Another object of the present invention is to reduce the time of HGPC production through fast reduction of salts.
SUMMARY
The following summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, example embodiments, and features described, further aspects, example embodiments, and features, will become apparent by reference to the drawings and the following detailed description.
Briefly, according to an example embodiment, a method for producing highly porous graphitized carbon (HPGC) at low temperature is disclosed. In an embodiment, the method involves introducing Iron (III) nitrate nonahydrate (Fe(NO3)3·9H2O) (hereinafter referred to as FeNOH) into a closed heated reactor, while maintaining the temperature in the reactor at 80°C to 150 °C inside the reactor. Gradually, FeNOH melts, and an organic precursor is steadily introduced into the reactor and mixed with the liquid FeNOH, forming a brown mixture. The brown mixture begins releasing nitrate fumes, which escape from the reactor and pass into a condenser. In the condenser, the nitrate fumes are exposed to or react with an acid or an oxidizing agent, resulting in the production of Nitric acid. The resulting nitric acid is then condensed up to room temperature of 15°C to 22°C and is collected for additional use. Meanwhile, the reactor continues to be heated until the brown mixture transforms into a sponge structure also referred to as a black sponge-like structure. The black sponge-like structure is either taken to or kept in an inert gas atmosphere within a temperature range of 700 °C to 1300 °C for a duration of 1-5 hours to obtain a ferrous carbon composite. The ferrous carbon composite is treated with Hydrochloric acid (HCl) of concentration 1.0 to 6.0 Molar (M) and then dried to obtain highly graphitized porous carbon (HPGC).
In an embodiment, the mass ratio of Iron (III) nitrate nonahydrate to organic precursor in the reactor is 1:10 to 10:1. More precisely the mass ratio of Iron (III) nitrate nonahydrate to the organic precursor is 4:1 to 1:4. The organic precursor is selected from a group comprising glucose, sucrose, chitosan, citric acid, urea, Phenol/Formaldehyde resins, citric acid, starch, cellulose, and kraft lignin, Petroleum Coke, Coal Tar Pitch, and polyacrylonitrile (PAN). The organic precursor is in fine powdered form when introduced into the reactor. In some embodiments, the reactor has milling properties for mixing. In some embodiment, the Iron (III) nitrate nonahydrate is heated at 100 °C to 120 °C for 2 to 5 minutes to melt the Iron (III) nitrate nonahydrate.
The organic precursor preferably comprises an organic compound capable of infiltrating the pores of the template phase and preferably being readily decomposable to form a carbon phase, optionally at elevated temperatures. In some non-limiting embodiments, for example, the carbon precursor comprises sucrose, glucose, phenol resin or furfuryl alcohol, or any kind of hydrocarbon polymer. These and other embodiments of the present disclosure are discussed in further detail hereinbelow.
BRIEF DESCRIPTION OF THE FIGURES
These and other features, aspects, and advantages of the example embodiments will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
FIG. 1A illustrates a microscopic view of a surface of a non-porous carbon, according to an example embodiment;
FIG. 1B illustrates a microscopic view of a surface of a porous graphitized carbon electrode to be used as an anode in an electrochemical device, according to an example embodiment;
FIG. 2 illustrates a schematic view of an electrochemical device having the graphitized carbon anode of FIG. 1B as an anode, according to an example embodiment;
FIG. 3 illustrates a process flow of manufacturing a porous graphitized carbon electrode, according to an example embodiment;
FIG. 4 is flowchart illustrating a method of manufacturing a porous graphitized carbon electrode, according to an example embodiment; and
FIGs. 5A-5B is a flowchart illustrating a method of manufacturing a porous graphitized carbon electrode and nitric acid, according to an example embodiment.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS
The drawings are to be regarded as being schematic representations and elements illustrated in the drawings are not necessarily shown to scale. Rather, the various elements are represented such that their function and general purpose become apparent to a person skilled in the art. Any connection or coupling between functional blocks, devices, components, or other physical or functional units shown in the drawings or described herein may also be implemented by an indirect connection or coupling. A coupling between components may also be established over a wireless connection. Functional blocks may be implemented in hardware, firmware, software, or a combination thereof.
Various example embodiments will now be described more fully with reference to the accompanying drawings in which only some example embodiments are shown. Specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments. Example embodiments, however, may be embodied in many alternate forms and should not be construed as limited to only the example embodiments set forth herein.
Accordingly, while example embodiments are capable of various modifications and alternative forms, example embodiments are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit example embodiments to the particular forms disclosed. On the contrary, example embodiments are to cover all modifications, equivalents, and alternatives thereof. Similarly, like numbers refer to like elements throughout the description of the figures.
Before discussing example embodiments in more detail, it is noted that some example embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the operations as sequential processes, many of the operations may be performed in parallel, concurrently or simultaneously. In addition, the order of operations may be re-arranged. The processes may be terminated when their operations are completed but may also have additional steps not included in the figure. The processes may correspond to methods, functions, procedures, subroutines, subprograms, etc.
Specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments. Inventive concepts may, however, be embodied in many alternate forms and should not be construed as limited to only the example embodiments set forth herein.
It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term "and/or" includes any, and all combinations of one or more of the associated listed items. The phrase "at least one of" has the same meaning as "and/or".
Further, although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, it should be understood that these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or section from another region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the scope of inventive concepts.
Spatial and functional relationships between elements (for example, between modules) are described using various terms, including “connected,” “engaged,” “interfaced,” and “coupled.” Unless explicitly described as being “direct,” when a relationship between first and second elements is described in the above disclosure, that relationship encompasses a direct relationship where no other intervening elements are present between the first and second elements, and also an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements. In contrast, when an element is referred to as being "directly” connected, engaged, interfaced, or coupled to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a fashion (e.g., "between," versus "directly between," "adjacent," versus "directly adjacent," etc.).
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a," "an," and "the," are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the terms “and/or” and “at least one of” include any and all combinations of one or more of the associated listed items. It will be further understood that the terms "comprises," "comprising," "includes," and/or "including," when used herein, specify the presence of stated features, integers, steps, operations, elements, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, elements, components, and/or groups thereof.
It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may in fact be executed substantially concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skills in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper”, and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in ‘addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below”, or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, term such as “below” may encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein are interpreted accordingly.
Portions of the example embodiments and corresponding detailed description may be presented in terms of software, or algorithms and symbolic representations of operation on data bits within a computer memory. These descriptions and representations are the ones by which those of ordinary skill in the art effectively convey the substance of their work to others of ordinary skill in the art. An algorithm, as the term is used here, and as it is used generally, is conceived to be a self-consistent sequence of steps leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of optical, electrical, or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like.
FIG. 1A illustrates a microscopic view of a surface 106 of a non-porous carbon 100A, according to an example embodiment. As shown, the surface 106 has a plurality of minimal pores 102a-102g. These pores do not help the electrolyte conduct well.
FIG. 1B illustrates a microscopic view of a surface 108 of a porous graphitized carbon electrode 100B to be used as an anode in an electrochemical device 202 (FIG. 2), according to an example embodiment. As shown, the surface 108 has a plurality of pores 104a-104n. The plurality of pores 104a-104n are more uniform than non-porous carbon due to our method. High adsorption occurs in such porous carbon 100B, as molecules adhere more to the surface 108. In an embodiment, the porous graphitized carbon electrode 100B is synthesized from a metal nitrate such as iron (III) nonahydrate (Fe(NO3)3·9H2O) and an organic precursor in a mass ratio ranging from 1:5 to 5:1. In an embodiment, the organic precursor is selected from a group comprising glucose, sucrose, chitosan, citric acid, urea, Phenol/Formaldehyde resins, citric acid, starch, cellulose, and kraft lignin, Petroleum Coke, Coal Tar Pitch, and polyacrylonitrile (PAN). Further, a porosity of the graphitized porous carbon is 80-95%. In an embodiment, the graphitized carbon electrode 100B, is obtained by the following process. The iron (III) nonahydrate (Fe(NO3)3·9H2O) is mixed in a reactor maintained at a first predefined temperature ranging from 80oC to 150oC with the organic precursor until turns a brown mixture that releases nitrate gases, is obtained.
The brown mixture is further heated at the first predefined temperature until the brown mixture releases nitrate gases and transforms into a black color sponge-like structure. The black color sponge-like structure is heated further in an inert atmosphere at a second predefined temperature of 700°C to 1300°C for a predefined time period to form a ferrous carbon composite. The predefined time period ranges from 1 to 5 hours. The ferrous carbon composite is then treated with an acid to form the highly porous graphitized porous carbon 100B. In an embodiment, the acid is Hydrochloric act (HCl) of concentration ranging from 1.0 to 6.0 Molar (M). The highly porous graphitized carbon (HPGC) 100B is widely used as an anode in electrochemical devices and is referred to as HPGC anode.
The HPGC serves as an anode material for energy storage systems, such as sodium-ion and potassium-ion batteries. The HPGC anode offers a large surface area, enhancing interaction with lithium ions in an electrochemical device, which in turn leads to better energy storage capacity. The HPGC anode provides high mechanical stability and thermal stability during repeat charge-discharge cycles. Further, it enables efficient lithium intercalation and deintercalation with minimal energy loss.
The porosity of the HPGC is 30-75% Due to the high porosity, fast ion diffusion and electron transport occurs thereby resulting in high power density and quick charge/ discharge cycles. A reversible capacity of 175 mAh/g – 300 mAh/g is noticed at current densities of 500 to 1000mA/g. Such high conductivity and chemical stability of HPGC enables it to be used in detecting biomolecules, gases, and ions with high sensitivity.
FIG. 2 illustrates a schematic view 200 of the electrochemical device 202 having the graphitized carbon anode (208) (also referred to as 100B in FIG. 1B), according to an example embodiment. As shown, the electrochemical device 202 has a negative electrode or the graphitized carbon anode (208), that is in contact with a negative current collector 206, a positive electrode or a cathode 214 in contact with a positive current collector 216, a separator 210 positioned between the negative electrode 208 and the positive electrode 214, and an electrolyte 212 in ionic contact with the positive electrode 214 and the negative electrode 208. In an embodiment, the positive electrode 214, the negative electrode 208 and the separator 210 comprise a sintered subassembly. The positive current collector 216 can be an aluminum current collector, and the negative current collector 206 can be a copper current collector. Current flows between the positive current collector 216 via a load 204 to the negative current collector 206.
FIG. 3 illustrates an environment 300 in which the manufacturing of the porous graphitized carbon electrode 208 is executed, according to an example embodiment. The environment 300 includes a reactor 302, a condenser 314,a collection tank 338, a tube furnace 320, an acid mixing tank 322, and a centrifugal dryer 330. Initially, a metal nitrate like an iron (III) nonahydrate (Fe(NO3)3·9H2O) (hereinafter referred to as FeNOH) is introduced into the reactor 302. The reactor is maintained at a temperature of 80oC to 150oC. The FeNOH is heated until it gets converted into a liquid form. For this the FeNOH is heated from 100 to 120oC for 2 to 5 minutes. Once the FeNOH is in the liquid form, an organic precursor 306 is slowly mixed into the FeNOH for 1 to 2 minutes and heated at the same temperature of 80oC to 150oC. The mixture is also grinded by am automatic mortar pestle grinding machine provided within the reactor 302. Gradually, the mixture turns into a brown mixture that releases nitrate gases 312. The nitrate gases 312 are emitted for 2 to 5 minutes. The nitrate gasses 312 are removed via an outlet 310 and transferred to the condenser 314. In an example embodiment, the condenser 314, the nitrate fumes 312 are reacted with an oxidizing agent or acid 316 to form nitric acid 336 at 12-15 degree Celsius.
Once the nitrate gases stop being emitted, the griding of the brown mixture is also ceased, and the brown mixture is left for 30 minutes at 120oC. The brown mixture changes appearance from brown to a black sponge-like structure 318 after 2 hours at 120oC. The black sponge-like structure 318 is taken out of the reactor 302 and put into a tube furnace 320 for calcination at a temperature of 700 oC.to 1300oC, in an inert gas atmosphere for 12 to 15 hours, to get a calcinated material. After calcination, the calcinated material is taken out of the tube furnace 320 and transferred to an acid mixing tank 322. In the calcinated material is treated with aqueous acid like aqueous hydrochloric acid (HCl) 326 that is passed through an inlet pipe 324 into the acid mixing tank 322 for 2 to 24 hours, to form ferrous carbon composite 328. After aforesaid acid treatment, the ferrous carbon composite 328 is centrifuged and dried at 120oC in a centrifugal dryer 330 to form HPGC 334. The centrifugal and drying process is carried out until a constant weight of HPGC 334 is obtained.
FIG. 4 is a flowchart 400 illustrating a method of manufacturing a porous graphitized carbon electrode, according to an example embodiment.

At 402, a metal nitrate such as iron (III) nonahydrate (Fe(NO3)3·9H2O) is introduced into a reactor. The reactor is maintained at a first predefined temperature ranging from 80oC to 150oC. Due to the heat the iron (III) nonahydrate (Fe(NO3)3·9H2O) melts into a liquid form within 2 to 5 minutes.

At 402, an organic precursor is mixed with the liquid form of the iron (III) nonahydrate (Fe(NO3)3·9H2O) in the reactor to form a sponge structure. Typically, upon being heated, the brown mixture releases nitrate gases and the brown mixture gets converted into a black sponge-like structure. The organic precursor is mixed in a ratio of 5:1 to 1:5 with the iron (III) nonahydrate (Fe(NO3)3·9H2O).

At 406, the sponge structure is further heated in an inert gas atmosphere at a second predefined temperature ranging from 700°C to 1300°C for a predefined time period ranging from 1 to 5 hours to obtain a ferrous carbon composite.

At 408, the ferrous carbon composite is treated with an acid to obtain the graphitized porous carbon electrode. In an embodiment, the acid is Hydrochloric acid (HCl) of concentration 2.0 molar (M). Alternatively, a concentration ranging from 1.0 M to 6.0 M of (HCl) can also be used.

A chemical reaction summarizing the above steps in the reactor and the condenser that results in the HPGC, and the nitric acid is shown hereinbelow:

In an embodiment, the HGPC is produced in a laboratory set-up, where a mortar and pestle are preheated at the range of 100°C -120°C. Into the mortar and pestle FeNOH is added and stirred for about 2 to 5 minutes until the FeNOH is converted into a liquid form. The organic precursor is added or mixed into to FeNOH. In an embodiment, a ratio of FeNOH to organic precursor is 2:1. The addition of the organic precursor can be done in 3 to 4 portions while grinding with an automatic mortar pestle grinding machine. The process of adding the organic precursor or biomass materials to iron nitrate liquid is completed within 1 to 2 minutes. After the addition of organic precursor to the liquid ferric nitrate nonahydrate (FeNOH) dense nitrate fumes get emitted in a short time span of 2 to 5 minutes. Once the emission of the nitrate fumes cease, grinding is also stopped, and the mixture is left for 30 minutes at 120 °C. The nitrate fumes generated are passed through an outlet of the reactor to a condenser where the nitrate fumes are brought in contact with an acid or an oxidizing agent. Upon reacting with the acid, the nitrate fumes are converted to nitric acid.

Further, as the mixture is heated, an appearance of the mixture changes from a brown to the black sponge-type structure after 2 hours at 120 °C. The black sponge-type structure is removed from the reactor and transferred to a tube furnace for calcination at a temperature range of 700°C to 1300°C in an inert gas atmosphere for 1 to 5 hours to get a calcinated material. After calcination, the calcinated material was taken out and treated with aqueous hydrochloric acid (HCl) for 2 to 24 hours. After the HCL treatment, the material is centrifuged and dried at 120°C until a constant weight is achieved. The resulting dried substance is the HGPC.
FIGs. 5A-5B is a flowchart 500 illustrating a method of manufacturing a porous graphitized carbon electrode and nitric acid, according to an example embodiment.

At 502, iron (III) nonahydrate (Fe(NO3)3·9H2O) is introduced into a reactor maintained at a first predefined temperature of from 80oC to 150oC.

At 504, the iron (III) nonahydrate (Fe(NO3)3·9H2O) is heated in the reactor at a temperature ranging from 100 °C to 120°C for a time duration for 2 to 5 minutes, until the iron (III) nonahydrate (Fe(NO3)3·9H2O) melts into a liquid form.

At 506, the organic precursor is mixed with the liquid form of the iron (III) nonahydrate (Fe(NO3)3·9H2O) to form a brown mixture.

At 508, the brown mixture is heated at the first predefined temperature until the brown mixture releases nitrate gases and transforms into a sponge structure.

At 510, the nitrate gases are passed from the reactor to a condenser that is maintained at a low temperature of 10°C to 15°C.

At 512, the nitrate gases are reacted in the condenser with an acid or an oxidizing agent to produce nitric acid.

At 514, the nitric acid is condensed up to room temperature of 15-22°C and is collected for further use. The byproduct nitric acid of this process is a useful product and can be used for multiple industrial and commercial purposes. Converting the nitrate gases into nitric acid also prevents environmental pollution, thereby making this process of manufacturing HPGC an environmentally friendly sustainable process.

At 516, the sponge structure is heated in an inert gas atmosphere at a second predefined temperature selected from 700°C to 1300°C for a predefined time period ranging from 1 to 5 hours to obtain a ferrous carbon composite.

At 518, the ferrous carbon composite is treated with an acid such as Hydrochloric acid (HCL) of concentration ranging from 1.0 M to 6.0 M, to obtain the highly porous graphitized carbon (HPGC) electrode.
The disclosed method for producing high porous graphitized carbon (HPGC) electrodes presents several advantages, particularly in terms of environmental sustainability and industrial scalability. This innovative approach effectively addresses the challenge of nitrate gas emissions during the production process. By utilizing glucose as a reducing agent, the method ensures the reduction of ferric nitrate (Fe(NO3)3) to Fe/Fe3C without requiring the addition of water. The reaction takes place in a heated reactor, where the nitrogen dioxide fumes generated during the process are captured and condensed to produce nitric acid. This not only prevents harmful emissions but also transforms a potential pollutant into a valuable by-product, aligning the process with principles of waste minimization and resource optimization.
The HPGC electrodes produced through this method exhibit high porosity, up to 75%. Such porosity facilitates fast ion diffusion and electron transport, which accelerates electrode kinetics by 25-30%, resulting in high power density and enabling quick charge/discharge cycles. Remarkably, these electrodes demonstrate a reversible capacity of 175-300 mAh/g at current densities of 500 to 1000 mA/g, reflecting their superior performance in energy storage applications. The high conductivity and chemical stability of HPGC make it highly effective not only in energy storage but also in detecting biomolecules, gases, and ions with exceptional sensitivity.
Another advantage of the method of manufacturing high-performance graphite composite (HPGC) is it ensures precise control over the thickness of the porous graphite while producing a surface that is free of micro-cracks. This results in superior material properties, such as higher cell energy density, enhanced power performance, and the ability to achieve higher voltages, making it particularly suitable for energy storage and high-power applications. Furthermore, the method of manufacturing the HPGC is solvent-free, eliminating the need for a separate solvent to create the porous graphite. Instead, Iron (III) nitrate nonahydrate acts as the reaction medium, directly interacting with the organic precursor. This not only simplifies the process but also makes it more efficient and environmentally sustainable by reducing the use of additional materials and avoiding solvent-related waste.
The elimination of nitrate gas emissions makes the process environmentally friendly and compliant with stringent regulatory standards, thereby offering a sustainable alternative for large-scale production. Moreover, the use of glucose ensures a controlled and efficient reaction, which contributes to the quality and uniformity of the HPGC electrode. The method’s design also supports industrial scalability, making it suitable for commercial applications while addressing environmental and economic concerns simultaneously.
In addition to its environmental benefits, the method enhances the electrochemical properties of the HPGC electrode. The resulting material exhibits high porosity and graphitization, making it ideal for applications in energy storage systems such as lithium-ion batteries. The conversion of nitrogen dioxide into nitric acid further adds economic value to the process, offsetting costs associated with emission control measures and increasing the overall efficiency of the production cycle.
By integrating environmental considerations with the need for high-quality material production, this method represents a significant advancement in the field of porous carbon electrode manufacturing. It paves the way for sustainable industrial practices without compromising the performance characteristics required for advanced energy storage technologies.
It will be understood by those within the art that, in general, terms used herein, are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present.
For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., “a” and/or “an” should be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, means at least two recitations, or two or more recitations).
While only certain features of several embodiments have been illustrated, and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of inventive concepts.
The aforementioned description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure may be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification. It should be understood that one or more steps within a method may be executed in a different order (or concurrently) without altering the principles of the present disclosure. Further, although each of the example embodiments is described above as having certain features, any one or more of those features described with respect to any example embodiment of the disclosure may be implemented in and/or combined with features of any of the other embodiments, even if that combination is not explicitly described. In other words, the example embodiments described are not mutually exclusive, and permutations of one or more example embodiments with one another remain within the scope of this disclosure.
The example embodiment or each example embodiment should not be understood as a limiting/restrictive of inventive concepts. Rather, numerous variations and modifications are possible in the context of the present disclosure, in particular those variants and combinations which may be inferred by the person skilled in the art with regard to achieving the object for example by combination or modification of individual features or elements or method steps that are described in connection with the general or specific part of the description and/or the drawings, and, by way of combinable features, lead to a new subject matter or to new method steps or sequences of method steps, including insofar as they concern production, testing and operating methods. Further, elements and/or features of different example embodiments may be combined with each other and/or substituted for each other within the scope of this disclosure.

,CLAIMS:We Claim:
1. An electrode for use in an electrochemical device, wherein the electrode comprises:
a graphitized porous carbon synthesized from a metal and an organic precursor in a mass ratio ranging from 1:5 to 5:1, wherein a porosity of the graphitized porous carbon is 80-95%.

2. The electrode of claim 1, wherein the graphitized porous carbon is made by:
mixing the iron (III) nonahydrate (Fe(NO3)3·9H2O) and the organic precursor in a reactor at a first predefined temperature ranging from 80oC to 150oC until the mixture turns into a brown mixture that releases nitrate gases,
heating the brown mixture at the first predefined temperature until the brown mixture transforms into a sponge structure,
heating the sponge structure in an inert atmosphere at a second predefined temperature of 700°C to 1300°C for predefined time period to a ferrous carbon composite, and
treating the ferrous carbon composite is treated with an acid to form the graphitized porous carbon.
3. The electrode of claim 1, wherein the metal nitrate is nitrate iron (III) nonahydrate (Fe(NO3)3·9H2O).

4. The electrode of claim 1, where in the predefined time period ranges from 1 to 5 hours.

5. The electrode of claim 1, where in the acid is hydrochloric acid having a concentration between 1.0 to 6.0 molar.

6. The electrode of claim 1 wherein the organic precursor is selected from a group comprising glucose, sucrose, chitosan, citric acid, urea, Phenol/Formaldehyde resins, citric acid, starch, cellulose, and kraft lignin, Petroleum Coke, Coal Tar Pitch, and polyacrylonitrile (PAN).

7. A method of manufacturing a graphitized porous carbon electrode for use in an electrochemical device, the method comprising:
introducing iron (III) nonahydrate (Fe(NO3)3·9H2O) into a reactor maintained at a first predefined temperature;
mixing an organic precursor with a liquid form of the iron (III) nonahydrate (Fe(NO3)3·9H2O) in the reactor to form a sponge structure;
heating the sponge structure in an inert gas atmosphere at a second predefined temperature for a predefined time period to obtain a ferrous carbon composite; and
treating the ferrous carbon composite with an acid to obtain the graphitized porous carbon electrode.

8. The method of claim 6, wherein the first predefined temperature ranges from 80oC to 150oC, and wherein the second predefined temperature ranges from 700°C to 1300°C, and wherein the predefined time period ranges from 1 to 5 hours.

9. The method of claim 6, wherein during the mixing, a mass ratio of the iron (III) nonahydrate (Fe(NO3)3·9H2O) to the organic precursor ranges from 1: 5 to 5:1.

10. The method of claim 6, further comprising:
heating the iron (III) nonahydrate (Fe(NO3)3·9H2O) in the reactor at a temperature ranging from 100 °C to 120°C for a time duration for 2 to 5 minutes, until the iron (III) nonahydrate (Fe(NO3)3·9H2O) melts into a liquid form;
mixing the organic precursor with the liquid form of the iron (III) nonahydrate (Fe(NO3)3·9H2O) to form a brown mixture; and
heating the brown mixture at the first predefined temperature until the brown mixture releases nitrate gases and transforms into the sponge structure.

11. The method of claim 9, further comprising:
passing the nitrate gases from the reactor to a condenser;
reacting the nitrate gases with an acid or an oxidizing agent to produce nitric acid; and
condensing the nitric acid up to room temperature of 15°C to 22°C.

12. The method of claim 6, wherein the organic precursor is selected from a group comprising glucose, sucrose, chitosan, citric acid, urea, Phenol/Formaldehyde resins, citric acid, starch, cellulose, and kraft lignin, Petroleum Coke, Coal Tar Pitch, and polyacrylonitrile (PAN).

13. An electrochemical device comprising:
a negative electrode comprising a graphitized porous carbon synthesized from iron (III) nonahydrate (Fe(NO3)3·9H2O) and an organic precursor in a mass ratio ranging from 1:5 to 5:1, wherein the negative electrode in electronic contact with a negative current collector in electric connection with an external circuit;
a positive electrode in electronic contact with a positive current collector in electric connection with the external circuit;
a separator positioned between the positive electrode and the negative electrode; and
an electrolyte in ionic contact with the positive and negative electrodes; wherein the positive electrode, the negative electrode and the separator comprise a sintered subassembly.
14. The electrochemical device of claim 12, wherein the graphitized porous carbon is made by:
mixing the iron (III) nonahydrate (Fe(NO3)3·9H2O) and the organic precursor in a reactor at a first predefined temperature ranging from 80oC to 150oC until the mixture turns into a brown mixture that releases nitrate gases,
heating the brown mixture at the first predefined temperature until the brown mixture transforms into a sponge structure,
heating the sponge structure in an inert atmosphere at a second predefined temperature of 700°C to 1300°C for predefined time period to a ferrous carbon composite, and
treating the ferrous carbon composite is treated with an acid to form the graphitized porous carbon.
15. The electrochemical device of claim 12, wherein a porosity of the graphitized porous carbon is 80-95%.

16. The electrochemical device of claim 12, wherein the organic precursor is selected from a group comprising glucose, sucrose, chitosan, citric acid, urea, Phenol/Formaldehyde resins, citric acid, starch, cellulose, and kraft lignin, Petroleum Coke, Coal Tar Pitch, and polyacrylonitrile (PAN).