Preparation method of coal-based porous graphene composite ternary material

Abstract

A method for preparing a coal-based porous graphene composite ternary material belongs to the field of materials preparation technology. The method is as follows: raw material refinement; carbonization of coal raw materials; mixing of activator and product; activation of the mixture; cleaning and drying of the activated product to obtain coal-based porous graphene material; mixing of ternary metal salts; mixing of the mixture with a lithium source to obtain a precursor material; sintering of the precursor material; cleaning and drying of the product to obtain the ternary material; composite material preparation: This invention uses low-cost coal as a porous carbon precursor, and effectively prepares coal-based porous graphene material through a method of carbonization followed by activation, which is suitable for mass production; the potassium-based activator simplifies the process and simultaneously catalyzes the graphitization process, promoting the synergistic development of pores and graphite microcrystalline structure; the coal-based porous graphene is combined with the ternary material, and a high-specific-energy hybrid capacitor cathode composite material is prepared based on the bulk surface synergistic energy storage mechanism.

Description

Technical Field

[0001] This invention relates to a method for preparing a coal-based porous graphene composite ternary material, belonging to the field of materials preparation technology. Background Technology

[0002] To address the low energy density of supercapacitors, Faraday electrodes (battery-type electrodes) are introduced into supercapacitors to form hybrid capacitors (such as lithium / sodium / potassium hybrid capacitors). This approach moderately sacrifices power density and cycle life to improve the device's energy density. The positive electrode material of the hybrid capacitor is a capacitive material, and its energy storage mechanism is a rapid adsorption / desorption process of ions at the electrode material / electrolyte interface, thus exhibiting high power density and long cycle life. The negative electrode material is a battery-type material, and its energy storage mechanism is an insertion / extraction process of ions within the electrode material, resulting in higher energy density. Hybrid capacitors significantly improve energy density without sacrificing power density and have a cycle life far exceeding that of lithium batteries. Currently, hybrid capacitors have an energy density of approximately 10-50 Wh / kg, a power density ≥10 kW / kg, a cycle life of 50,000-100,000 cycles, and a working life of up to 10 years.

[0003] Electrode materials are a key component affecting the energy storage performance of hybrid capacitor systems. Developing highly active and stable electrode materials is a crucial direction for the development of supercapacitors. Ideal cathode materials should possess high conductivity, good mechanical properties, stable chemical properties, and a high specific surface area. In hybrid capacitor cathode materials, activated carbon, metal oxides, and conductive polymers are widely used due to their unique electrochemical properties. However, there is still room for improvement in the specific energy and specific power of these materials; therefore, developing novel high-performance electrode materials has become a current research focus.

[0004] Porous carbon materials belong to the category of nanomaterials. They are network structures composed of interconnected or closed pores, exhibiting tunable porosity and structure. By controlling the pore distribution characteristics of porous materials to achieve high specific surface area and pore volume, ion diffusion channels can be expanded. Simultaneously, controlling the microcrystalline structure to ensure its full development can improve the material's electrical conductivity and chemical stability. Based on the microcrystalline development of porous carbon and the structure-property relationship between pore structure and application performance, constructing porous carbon with high specific surface area and high-quality graphite microcrystals is an important goal for preparing high-performance electrode functional materials.

[0005] Low-cost preparation methods and the selection of precursors (carbon-based materials) are crucial in determining the morphology, properties, and application performance of porous carbon materials. Based on existing technologies, porous carbon is generally prepared internationally using template methods, physical activation methods, and chemical activation methods. Template methods involve depositing porous carbon precursors into the pores or surface of a template, followed by template removal to obtain porous nanomaterials with the same morphology and size as the template. However, this method requires the carbon-based material to have good flowability to mix uniformly with the template. For solid precursors, complex pretreatment processes are required, resulting in high costs. Furthermore, template methods lack the ability to regulate the microcrystalline structure, making it difficult to fully develop the carbon microcrystalline structure. Physical activation mainly involves the oxidative etching effect of weak oxidizing gases (such as carbon dioxide and water vapor) on the carbon-based material. This process is influenced by factors such as gas adsorption, oxidative etching, and product diffusion rates. Porous carbon materials obtained through physical activation are predominantly micropores with a narrow pore size distribution. Chemical activation achieves pore development through the chemical reaction between chemical reagents and the precursor. Compared to physical activation, chemical activation exhibits higher carbon yield and specific surface area. The activation mechanism of general chemical activators (such as protic acids) mainly promotes the catalytic dehydration of hydroxyl functional groups in coal-based materials; their pore-forming process is relatively mild and cannot achieve extensive porosity. Potassium-based activators (such as potassium hydroxide and potassium ferrate) achieve pore formation through their strong corrosiveness and high-temperature oxidation. Simultaneously, intermediate products during the activation process (such as elemental potassium) catalyze the graphitization process of carbon materials and intercalate into the interlayer of graphite microcrystals, further generating pores and increasing the specific surface area.

[0006] Biomass and coal, as natural solid carbon resources, contain high carbon density and can be used as precursors for the preparation of porous carbon materials. However, carbon materials with different structures exhibit significant differences in internal porosity, surface chemical properties, and mechanical properties. The carbon structure in biomass contains numerous oxygen-containing groups (hydroxyl, carboxyl, carbonyl, ether bonds, etc.), long aliphatic side chains, and (semi-)cellulose or lignin structures formed by the cross-linking of heterocycles, with a low degree of aromatic polymerization. Due to the diversity of biomass sources, its microstructure exhibits various irregular structures such as spherical, fibrous, sheet-like, tubular, and rod-like shapes. By activating biomass carbon sources and removing the abundant organic and volatile components, carbon materials with a certain pore size structure can be obtained. However, during the preparation of well-developed pores, a certain degree of pyrolysis and condensation reactions occur within the structure, generating a large number of unpaired electrons and forming five-membered and seven-membered heterocyclic rings. This leads to a certain degree of distortion and deformation of the structural sheets, resulting in poor structural stability of biomass-based porous carbon, which cannot meet the high stability requirements of supercapacitor electrode materials.

[0007] Coal, as my country's primary energy source, boasts abundant reserves and low cost, providing the necessary conditions for the large-scale production of porous carbon. Compared to biomass, coal has a denser microcrystalline structure, formed from the ordered macromolecular structure of plants through dehydrogenation, deoxygenation, and aromatization polymerization. This offers greater possibilities for using coal as a carbon precursor to prepare porous carbon and for the synergistic regulation of its microcrystalline and pore structure development. (The last sentence appears to be incomplete and possibly refers to a separate topic: "sp in coal...") 3 Carbon is the main connecting structure of graphite crystallites and is also the structure that reacts more readily with activators. By first carbonizing coal, the crystal structure becomes more regularly arranged, and the crystallite size is larger, resulting in higher structural stability. Subsequent chemical activation allows for deep synergistic control of pore size and graphite crystallites, yielding coal-based porous graphene materials.

[0008] Coal-based porous graphene cathode materials exhibit great application potential in hybrid capacitors due to their high specific surface area and excellent conductivity. Currently, the preparation methods for coal-based porous graphene cathodes mainly involve carbonization and activation reactions. Through high-temperature carbonization and activation processes, the carbon source material is transformed into a graphitized porous carbon structure, followed by pulverization and sieving to obtain porous carbon powder of the desired particle size. Finally, surface treatment is used to improve the electrochemical performance of the porous carbon material. However, due to the limitation of the ion surface storage mechanism, although coal-based porous graphene cathode materials can achieve rapid charge and discharge, their energy density remains insufficient, restricting their performance in practical applications.

[0009] Ternary materials, such as lithium nickel cobalt manganese oxide (LiNi x Co y Mn 1-x-y O2, due to its high specific capacity and stable cycle performance, has become one of the preferred cathode materials for lithium-ion batteries and hybrid capacitors. The preparation methods for ternary materials mainly include solid-state methods, co-precipitation methods, sol-gel methods, and template methods. Although ternary materials have the advantage of high energy density, their cycle life is relatively short, their cost is high, and their performance decays rapidly at high temperatures. Especially as cathode materials for hybrid capacitors, the bulk ion storage process limits their rate performance.

[0010] In summary, coal-based porous graphene cathode materials struggle to meet the demands for high energy density, while ternary cathode materials, although possessing high specific capacity, suffer from poor rate performance, high cost, and short cycle life. Therefore, developing novel coal-based porous graphene composite ternary materials as hybrid capacitor cathode materials aims to overcome the respective shortcomings of both. The high-specific-energy hybrid capacitor cathode preparation method based on coal-based porous graphene composite ternary materials aims to fully utilize the surface adsorption ion storage mechanism of coal-based porous graphene and the bulk intercalation ion storage mechanism of ternary materials through the composite of coal-based porous graphene and ternary materials, achieving a synergistic effect between the materials and thus preparing a high-specific-energy hybrid capacitor cathode composite material. This preparation method is expected to provide new ideas and technical support for the research and development of hybrid capacitor electrode materials, promoting the development and application of hybrid capacitor technology. Summary of the Invention

[0011] To address the problems existing in the background technology, the present invention provides a method for preparing coal-based porous graphene composite ternary materials.

[0012] To achieve the above objectives, the present invention adopts the following technical solution: a method for preparing a coal-based porous graphene composite ternary material, the method comprising the following steps:

[0013] S1: Raw material refinement: The coal raw material is crushed, ground and screened in sequence to obtain refined coal powder; the particle size of the refined coal powder is 60 mesh to 200 mesh.

[0014] S2: Carbonization of coal raw materials: Fine coal powder is placed in an atmosphere furnace, the temperature is raised to the specified carbonization temperature and held for a period of time, and then the atmosphere furnace is naturally cooled to room temperature to obtain carbonized solid material.

[0015] S3: Mixing of activator and product: The carbonized solid material with a mass ratio of 1:0.1 to 10 is thoroughly mixed with a chemical activator to obtain a mixture; the chemical activator is one or more potassium-based activators.

[0016] S4: Activation of the mixture: Transfer the mixture to a crucible and place it in an atmosphere furnace. Raise the temperature to the specified activation temperature and hold it for a period of time. Then, allow the atmosphere furnace to cool naturally to room temperature to obtain the activated mixed solid material.

[0017] S5: Cleaning and drying of the activated product: The activated mixed solid material is subjected to acid washing and water washing in sequence until the supernatant is neutral. The cleaned solid material is then dried to obtain coal-based porous graphene material.

[0018] S6: Mixing of ternary metal salts: Nickel salt, cobalt salt, and manganese salt are mixed in any proportion to obtain a mixture; wherein the nickel salt, cobalt salt, and manganese salt are the corresponding sulfate, carbonate, chloride, fluoride, or hydroxide. The mixing method is co-precipitation, liquid-phase mixing, or solid-phase mixing.

[0019] S7: Mixing of the mixture with a lithium source: The mixture is mixed with a lithium source to obtain a precursor material; the lithium source is lithium carbonate, lithium hydroxide, lithium nitrate, or lithium chloride. The mixing method is liquid-phase mixing or solid-phase mixing.

[0020] S8: Sintering of precursor materials: The precursor materials are placed in an atmosphere furnace, the temperature is raised to a specified temperature and held for a period of time, and then the atmosphere furnace is naturally cooled to room temperature to obtain the sintered mixed solid material.

[0021] S9: Cleaning and drying of the product: The sintered mixed solid material is acid-washed and water-washed sequentially until the supernatant is neutral. The cleaned solid material is then dried to obtain the ternary material.

[0022] The pickling solutions used in S5 and S9 are all dilute hydrochloric acid, dilute nitric acid or dilute acetic acid, and the concentration of the pickling solution is 0.01mol / L to 10mol / L.

[0023] S10: Preparation of composite materials: Coal-based porous graphene material with a mass ratio of 1:100 to 100:1 is mixed with ternary material to obtain coal-based porous graphene composite ternary material.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] This invention utilizes low-cost coal as a porous carbon precursor and effectively prepares coal-based porous graphene materials suitable for mass production through a carbonization-activation method. A potassium-based activator simplifies the process while simultaneously catalyzing the graphitization process, promoting the synergistic development of pores and graphite microcrystalline structures. The coal-based porous graphene is then combined with ternary materials to prepare a high-energy-density hybrid capacitor cathode composite material based on a bulk-surface synergistic energy storage mechanism. This invention not only broadens the application fields of coal but also improves the performance of energy storage materials, providing new ideas for the development of energy storage technologies such as hybrid capacitors, and has broad application prospects and significant economic value. Attached Figure Description

[0026] Figure 1 This is a SEM image of the coal-based porous graphene composite ternary material prepared in Example 1 of this invention;

[0027] Figure 2 This is the Raman spectrum of the coal-based porous graphene composite ternary material prepared in Example 1 of the present invention;

[0028] Figure 3 These are electrochemical characteristic diagrams of the coal-based porous graphene composite ternary material prepared in Example 1 of the present invention, wherein: (a) is the cyclic voltammetry curve of the coal-based porous graphene-based supercapacitor; (b) is the constant current charge-discharge curve of the coal-based porous graphene-based supercapacitor.

[0029] Figure 4 This is a SEM image of the coal-based porous graphene composite ternary material prepared in Example 2 of this invention;

[0030] Figure 5 This is the Raman spectrum of the coal-based porous graphene composite ternary material prepared in Example 2 of the present invention;

[0031] Figure 6 These are electrochemical characteristic diagrams of the coal-based porous graphene composite ternary material prepared in Example 2 of the present invention, wherein: (a) is the cyclic voltammetry curve of the coal-based porous graphene-based supercapacitor; (b) is the GCD curve of the coal-based porous graphene-based supercapacitor.

[0032] Figure 7 This is a SEM image of the coal-based porous graphene composite ternary material prepared in Example 3 of the present invention;

[0033] Figure 8 This is a TEM image of the coal-based porous graphene composite ternary material prepared in Example 3 of the present invention;

[0034] Figure 9 These are comparison diagrams of nitrogen adsorption curves and pore size distribution curves of the coal-based porous graphene composite ternary materials prepared in Examples 1-3 of the present invention, wherein: (a) is a nitrogen adsorption / desorption isotherm diagram; (b) is a pore size distribution curve diagram;

[0035] Figure 10 These are electrochemical characteristic diagrams of the organic supercapacitor based on coal-based porous graphene composite ternary material prepared in Example 3 of the present invention, wherein: (a) is the cyclic voltammetry curve of the coal-based porous graphene-based supercapacitor; (b) is the constant current charge-discharge curve of the coal-based porous graphene-based supercapacitor.

[0036] Figure 11 The figures are the cyclic voltammetry curves and constant current charge-discharge curves of a lithium-ion capacitor prepared in Example 3 of the present invention, with the coal-based porous graphene composite ternary material as the positive electrode and the niobium-based oxide as the negative electrode. (a) is the cyclic voltammetry curve; (b) is the constant current charge-discharge curve. Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0038] A method for preparing a coal-based porous graphene composite ternary material, the method comprising the following steps:

[0039] S1: Raw material refinement: The coal raw material is crushed, ground and screened in sequence to obtain refined coal powder; the particle size of the refined coal powder is 60 mesh to 200 mesh.

[0040] The coal raw material is low-cost coal without any pretreatment. Its industrial analysis shows that the moisture content is 0-15%, the ash content is 0-5%, the volatile matter content is 0-40%, and the fixed carbon content is more than 50%. The elemental analysis shows that the carbon content is more than 70%, the hydrogen content is 0%-10%, and the oxygen content is 0%-20%.

[0041] S2: Carbonization of coal raw materials: Fine coal powder is placed in an atmosphere furnace (the atmosphere of the atmosphere furnace is high-purity nitrogen or high-purity argon, and the volume flow rate of the atmosphere is 50 mL / min to 500 mL / min. The heating rate of the atmosphere furnace is 0.1℃ / min to 20℃ / min), the temperature is raised to the specified carbonization temperature (600℃ to 1200℃) and held for a period of time (0.5h to 10h), and then the atmosphere furnace is naturally cooled to room temperature to obtain the carbonized solid material;

[0042] S3: Mixing of activator and product: The carbonized solid material with a mass ratio of 1:0.1 to 10 is thoroughly mixed with a chemical activator by ball milling or liquid phase mixing to obtain a mixture; the chemical activator is one or more potassium-based activators (such as potassium hydroxide, potassium carbonate, potassium bicarbonate, potassium ferrate, etc.).

[0043] S4: Activation of the mixture: Transfer the mixture to a crucible and place it in an atmosphere furnace (the atmosphere of the atmosphere furnace is high-purity nitrogen or high-purity argon, and the volumetric flow rate of the atmosphere is 50 mL / min to 500 mL / min. The heating rate of the atmosphere furnace is 0.1℃ / min to 20℃ / min). Raise the temperature to the specified activation temperature (600℃ to 1200℃) and hold it for a period of time (0.5h to 10h). Then, allow the atmosphere furnace to cool naturally to room temperature to obtain the activated mixed solid material.

[0044] S5: Cleaning and drying of the activated product: The activated mixed solid material is sequentially acid-washed and water-washed, using vacuum filtration or centrifugation for solid-liquid separation. After the supernatant becomes neutral, the cleaned solid material is dried using vacuum drying, hot air drying, or natural evaporation. The drying temperature is 60–160℃, and the drying time is 6–24 hours. Coal-based porous graphene material is obtained.

[0045] S6: Mixing of ternary metal salts: Mixing nickel salt, cobalt salt and manganese salt in any proportion to obtain a mixture;

[0046] The nickel salt, cobalt salt, and manganese salt are the corresponding sulfates, carbonates, chlorides, fluorides, or hydroxides.

[0047] The mixing method is co-precipitation, liquid-phase mixing, or solid-phase mixing.

[0048] S7: Mixing the mixture with the lithium source: Mix the mixture with the lithium source to obtain the precursor material;

[0049] The lithium source is lithium carbonate, lithium hydroxide, lithium nitrate, or lithium chloride.

[0050] The mixing method is either liquid-phase mixing or solid-phase mixing.

[0051] S8: Sintering of precursor materials: The precursor material is placed in an atmosphere furnace (the atmosphere of the atmosphere furnace is high-purity oxygen or air or a mixture of gases containing oxygen, and the volumetric flow rate of the atmosphere is 50 mL / min to 500 mL / min. The heating rate of the atmosphere furnace is 0.1℃ / min to 20℃ / min), the temperature is raised to the specified temperature (200℃ to 1600℃) and held for a period of time (0.5h to 24h), and then the atmosphere furnace is naturally cooled to room temperature to obtain the sintered mixed solid material;

[0052] S9: Cleaning and Drying of the Product: The sintered mixed solid material is sequentially acid-washed and water-washed. Cleaning methods include vacuum filtration or solid-liquid separation using a centrifuge. Once the supernatant is neutral, the cleaned solid material is dried using vacuum drying, hot air drying, or natural evaporation. The drying temperature is 60–160℃, and the drying time is 6–24 hours. Ternary materials are obtained.

[0053] The pickling solutions used in S5 and S9 are all dilute hydrochloric acid, dilute nitric acid or dilute acetic acid, and the concentration of the pickling solution is 0.01mol / L to 10mol / L.

[0054] S10: Preparation of composite materials: Coal-based porous graphene material with a mass ratio of 1:100 to 100:1 is mixed with ternary material in the form of liquid-phase mixing and solid-phase mixing to obtain coal-based porous graphene composite ternary material.

[0055] This invention uses low-cost coal as raw material. Through thorough mixing of an activator and coal powder, a process involving carbonization followed by activation and subsequent cleaning and drying, high-quality coal-based porous graphene materials with synergistically developed graphite microcrystals and well-defined pores are prepared. The pore arrangement and microcrystalline structure of the porous graphene can be controlled by altering the carbonization temperature, activation temperature, and activator dosage. The resulting porous graphene achieves a specific surface area of ​​up to 2615 m². 2 g -1 The total pore volume can reach 1.60 cm³. 3 g -1 Furthermore, the micropore size is mainly distributed between 0.7 and 1 nm, while containing a large number of mesopores and macropores, providing sufficient space and rapid transport channels for the storage and diffusion of electrolyte ions.

[0056] Using nickel, cobalt, and manganese salts as raw materials, and employing methods such as high-temperature solid-state synthesis, co-precipitation, sol-gel synthesis, hydrothermal synthesis, or combustion, different types of ternary materials are prepared by varying the proportions of the three metal salt raw materials. This allows for the control of the microcrystalline structure of the ternary materials and the realization of bulk ion storage. By mixing coal-based porous graphene and ternary materials in different proportions and through various methods such as mechanical mixing, liquid-phase mixing, and low-temperature sintering, a hybrid capacitor cathode material based on coal-based porous graphene and ternary materials is obtained. When applied to lithium-ion capacitor cathode materials, and influenced by factors such as the mixing ratio and method, it is expected to achieve higher performance. This invention has broad application prospects in energy storage technologies (such as hybrid capacitors).

[0057] Example 1:

[0058] S1: Raw material refinement: Take 3g of Zhundong coal and crush, grind and sieve it sequentially to obtain refined coal powder. The particle size of the refined coal powder is 120 mesh to 160 mesh.

[0059] S2: Carbonization of coal raw materials: Fine coal powder is placed in a high-purity nitrogen atmosphere furnace with a volume flow rate of 200 mL / min and a heating rate of 5℃ / min. The temperature is raised to the specified carbonization temperature of 700℃ and held for 1 hour. Then the atmosphere furnace is naturally cooled to room temperature to obtain the carbonized solid material.

[0060] S3: Mixing of activator and product: The carbonized solid material with a mass ratio of 1:4 and the chemical activator potassium hydroxide are thoroughly mixed in a liquid phase to obtain a mixture.

[0061] S4: Activation of the mixture: The mixture is transferred to a nickel crucible and placed in a horizontal tube high-purity nitrogen atmosphere furnace with a volume flow rate of 200 mL / min. The heating rate of the atmosphere furnace is 5℃ / min. The temperature is raised to the specified activation temperature of 1000℃ and held for 1 hour. Then the atmosphere furnace is allowed to cool naturally to room temperature to obtain the activated mixed solid material.

[0062] S5: Cleaning and drying of the activated product: The activated mixed solid material was sequentially acid-washed three times with dilute hydrochloric acid at a concentration of 5 mol / L, and then washed with water until the supernatant was a neutral liquid with a pH of 7. The cleaning method was vacuum filtration; the cleaned solid material was then vacuum-dried at a temperature of 100℃ for 12 hours to obtain coal-based porous graphene material.

[0063] S6: Mixing of ternary metal salts: Nickel hydroxide, cobalt hydroxide and manganese hydroxide in a mass ratio of 1:1:1 are mixed by solid-phase mixing to obtain a mixture;

[0064] S7: Mixing of the mixture with the lithium source: The mixture is mixed with lithium carbonate by solid-phase mixing to obtain the precursor material.

[0065] S8: Sintering of precursor materials: The precursor materials are placed in an atmosphere furnace with an air atmosphere at a volume flow rate of 100 mL / min; the heating rate of the atmosphere furnace is 5℃ / min; the temperature is raised to the specified temperature of 800℃ and held for 2 hours, and then the atmosphere furnace is naturally cooled to room temperature to obtain the sintered mixed solid material.

[0066] S9: Cleaning and drying of the product: The sintered mixed solid material was sequentially acid-washed and water-washed with 2 mol / L dilute hydrochloric acid until the supernatant was neutral. The cleaning method was vacuum filtration. The cleaned solid material was then dried under vacuum at 100℃ for 12 hours to obtain the ternary material.

[0067] S10: Coal-based porous graphene material and ternary material in a mass ratio of 1:1 are mixed by solid-phase mixing to obtain coal-based porous graphene composite ternary material.

[0068] Experimental results:

[0069] like Figure 1 The image shows an SEM image of the coal-based porous graphene composite ternary material prepared in Example 1. It can be seen from the image that after carbonization at 700℃ and activation with potassium hydroxide at 1000℃ for 1 hour, a "petal-like" texture appears on the surface of the carbon material, and the "petal-like" morphology is almost all over the entire carbon structure.

[0070] like Figure 2The image shows the Raman spectrum of the coal-based porous graphene composite ternary material prepared in Example 1, indicating that the carbon material underwent a deep graphitization process.

[0071] like Figure 3 As shown, the electrochemical characteristics of the coal-based porous graphene composite ternary material prepared in Example 1 are shown. The CV curves all exhibit a quasi-rectangular shape, demonstrating typical capacitive charge storage behavior.

[0072] Example 2:

[0073] The difference between this embodiment and Embodiment 1 is that:

[0074] S1: Take 5g of Zhundong coal

[0075] S4: Raise the temperature to the specified activation temperature of 1000℃ and hold for 5 hours.

[0076] S5: Drying temperature is 80℃;

[0077] S9: Drying temperature is 80℃;

[0078] Experimental results:

[0079] like Figure 4 The image shows an SEM image of the coal-based porous graphene composite ternary material prepared in Example 2. It can be seen from the image that after carbonization at 700℃ and activation with potassium hydroxide at 1000℃ for 5 hours, a "petal-like" texture appears on the surface of the material. The texture of the material prepared in Example 1 shows more significant fluctuations and deeper wrinkles.

[0080] like Figure 5 The image shows the Raman spectrum of the coal-based porous graphene composite ternary material prepared in Example 2. Compared with the material prepared in Example 1, it exhibits deeper graphitization and fewer defects.

[0081] like Figure 6 The figure shows the electrochemical characteristics of the organic supercapacitor based on coal-based porous graphene composite ternary material prepared in Example 2. Compared with the material prepared in Example 1, the double-layer capacitance behavior is more pronounced with the extension of activation time, which is related to the further increase in the degree of graphitization. However, this enhanced graphitization is accompanied by a significant decrease in specific capacitance, mainly due to the loss of pore structure under high temperature and long-term treatment.

[0082] Example 3:

[0083] The difference between this embodiment and Embodiment 1 is that:

[0084] S4: Raise the temperature to the specified activation temperature of 900℃ and keep it at that temperature for 1 hour;

[0085] S5: Drying temperature is 80℃, drying time is 12h.

[0086] S9: Drying temperature is 80℃, drying time is 12h.

[0087] Experimental results:

[0088] like Figure 7 The image shows a SEM image of the coal-based porous graphene composite ternary material prepared in Example 3. It can be seen from the image that after carbonization at 700℃ and activation with potassium hydroxide at 900℃ for 1 hour, "petal-like" textures appear on the surface of the Zhundong coal, which are almost all over the entire carbon structure.

[0089] like Figure 8 The image shown is a TEM image of the coal-based porous graphene composite ternary material prepared in Example 3, in which obvious graphite bands are visible.

[0090] like Figure 9 The figure shows a comparison of nitrogen adsorption curves and pore size distribution curves of the coal-based porous graphene composite ternary materials prepared in Examples 1-3. This material not only possesses a highly graphitized structure but also exhibits relatively high specific surface area and pore volume.

[0091] like Figure 10 As shown, the electrochemical characteristics of the organic supercapacitor based on the coal-based porous graphene composite ternary material prepared in Example 3 are illustrated. The CV curves all exhibit a quasi-rectangular shape, demonstrating typical capacitive charge storage behavior. More importantly, even with increased scan rates, the curve shapes remain relatively regular, proving their excellent charge-discharge efficiency. The GCD curves also show a considerably long discharge time, reflecting a large specific capacitance value. This is because the material possesses both well-developed porosity and a graphite lattice structure. This structural optimization enables the electrodes to more effectively store and conduct ions during electrochemical reactions, thereby improving energy and power density.

[0092] like Figure 11 The figure shows the cyclic voltammetry curve and constant current charge-discharge curve of a lithium-ion capacitor with coal-based porous graphene composite ternary material as the positive electrode and niobium-based oxide as the negative electrode prepared in Example 3. Under the influence of composite ratio, method and other conditions, and by optimizing the kinetic matching ratio between it and the negative electrode material, it is expected to achieve higher performance.

[0093] This invention relates to a method for preparing a high-energy-density hybrid capacitor cathode material capable of synergistic ion storage on both the surface adsorption and storage of ions by porous graphene materials with high specific surface area obtained from coal activated by potassium-based activators, and the bulk storage of ions by ternary materials such as lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, or other ternary materials using nickel, cobalt, and manganese salts as raw materials, with adjustable nickel-cobalt-manganese ratios. Addressing the bottleneck of traditional surface adsorption storage cathode materials for hybrid capacitors in achieving high energy density storage, this invention employs a method of combining coal-based porous graphene with ternary materials to prepare a high-energy-density hybrid capacitor cathode material that combines both bulk and surface storage capabilities.

[0094] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0095] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing a coal-based porous graphene composite ternary material, characterized in that: The method includes the following steps: S1: Raw material refinement: The coal raw material is crushed, ground and screened in sequence to obtain refined coal powder of 60 mesh to 200 mesh; S2: Carbonization of coal raw materials: Fine coal powder is placed in an atmosphere furnace, the temperature is raised to the specified carbonization temperature and held for a period of time, and then the atmosphere furnace is naturally cooled to room temperature to obtain carbonized solid material. S3: Mixing of activator and product: The carbonized solid material with a mass ratio of 1:0.1~10 is thoroughly mixed with one or more potassium-based activators to obtain a mixture; S4: Activation of the mixture: Transfer the mixture to a crucible and place it in an atmosphere furnace. Raise the temperature to the specified activation temperature and hold it for a period of time. Then, allow the atmosphere furnace to cool naturally to room temperature to obtain the activated mixed solid material. S5: Cleaning and drying of the activated product: The activated mixed solid material is subjected to acid washing and water washing in sequence until the supernatant is neutral. The cleaned solid material is then dried to obtain coal-based porous graphene material. S6: Mixing of ternary metal salts: Nickel salt, cobalt salt, and manganese salt are mixed in any proportion to obtain a mixture; the mixing method is co-precipitation, liquid-phase mixing, or solid-phase mixing; S7: Mixing the mixture with a lithium source: The mixture is mixed with a lithium source to obtain a precursor material; the lithium source is lithium carbonate, lithium hydroxide, lithium nitrate or lithium chloride; S8: Sintering of precursor materials: The precursor materials are placed in an atmosphere furnace, the temperature is raised to a specified temperature and held for a period of time, and then the atmosphere furnace is naturally cooled to room temperature to obtain the sintered mixed solid material. S9: Cleaning and drying of the product: The sintered mixed solid material is acid-washed and water-washed sequentially until the supernatant is neutral. The cleaned solid material is then dried to obtain the ternary material. The pickling solutions used in S5 and S9 are all dilute hydrochloric acid, dilute nitric acid or dilute acetic acid, and the concentration of the pickling solution is 0.01 mol / L to 10 mol / L. S10: Preparation of composite materials: Coal-based porous graphene material with a mass ratio of 1:100~100:1 is mixed with ternary material to obtain coal-based porous graphene composite ternary material.

2. The method for preparing a coal-based porous graphene composite ternary material according to claim 1, characterized in that: The nickel salt, cobalt salt, and manganese salt mentioned in S6 are the corresponding sulfates, carbonates, chlorides, fluorides, or hydroxides.

3. The method for preparing a coal-based porous graphene composite ternary material according to claim 1, characterized in that: The mixing method described in S7 is liquid-phase mixing or solid-phase mixing.

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