Coal-based graphitized carbon based on molten salt liquid-phase carbon formation and preparation method of coal-based graphitized carbon

Abstract

The invention belongs to the technical field of carbon material processing, and discloses coal-based graphitized carbon based on molten salt liquid-phase carbon formation and a preparation method thereof.The preparation method comprises the steps that pulverized coal is treated through a hydrogen peroxide solution, and a depolymerized precursor product is obtained; uniformly mixing the precursor product with binary eutectic mixed salt to obtain a solid-phase mixture; pyrolyzing the solid-phase mixture in an inert atmosphere at 850-950 DEG C for 2-4 hours to obtain a pyrolysis product; the pyrolysis product is washed with water, binary eutectic mixed salt in the pyrolysis product is dissolved, and a washed product is obtained; and carrying out de-ashing treatment on the water washing product, and washing to obtain the coal-based graphitized carbon based on molten salt liquid-phase carbon formation. The coal-based graphitized porous carbon is obtained through a molten salt pyrolysis method, the preparation process is relatively simple, and large-scale preparation of the coal-based graphitized porous carbon is expected to be achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon material processing, and particularly relates to a coal-based graphitized carbon based on molten salt liquid-phase carbonization and a preparation method thereof. Background Art

[0002] Porous carbons have advantages such as large specific surface area and pore volume, adjustable pore configuration, and rich geometric shapes, enabling them to play an excellent role in the applications in the diversified energy field. Nevertheless, the amorphous nature of porous carbons leads to their poor electrical conductivity and stability, which prompts the need to consider the improvement of graphitization degree in the structural design of porous carbons. As a typical class of heavy carbon precursors, the coal molecular skeleton is naturally cross-linked by highly condensed aromatic ring structures, showing great potential in the preparation of highly graphitized carbon. However, most of the current development methods for the graphitization of coal-based carbon sources still remain in the aspect of high-temperature solid-phase transformation, and at least a temperature of 2500 °C is required to drive the ordered rearrangement of carbon atoms, and it has little effect on hard carbon precursors that are difficult to graphitize [Hard carbons for sodium-ion batteries: Structure, analysis, sustainability, and electrochemistry [J]. Materials Today, 2019, 23: 87 - 104]. Although the formation of ordered carbon by chemical vapor deposition of coal pyrolysis gas has been reported in some cases [An investigation of growth mechanism of coal derived graphene films [J]. Materials Today Communications, 2017, 11: 147 - 155], this method is also difficult to achieve the large-scale preparation of coal-based graphitized carbon due to the complex gas components, low space-time yield, and high cost. Summary of the Invention

[0003] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a coal-based graphitized carbon based on molten salt liquid-phase carbonization and a preparation method thereof. The present invention obtains coal-based graphitized porous carbon through the method of molten salt pyrolysis, and the preparation process is relatively simple, and it is expected to achieve the large-scale preparation of coal-based graphitized carbon.

[0004] To achieve the above purpose,

[0005] The present invention adopts the following technical solutions:

[0006] A preparation method of a coal-based graphitized carbon based on molten salt liquid-phase carbonization, comprising the following process:

[0007] Treat pulverized coal with hydrogen peroxide solution to obtain a depolymerized precursor product;

[0008] Mix the precursor product with the binary eutectic mixed salt to obtain a solid-phase mixture;

[0009] Pyrolyze the solid-phase mixture in an inert atmosphere at 850 - 950 °C for 2 - 4 h to obtain a pyrolysis product;

[0010] Wash the pyrolysis product with water to dissolve the binary eutectic mixed salt in the pyrolysis product, obtaining a washed product;

[0011] Perform deashing treatment and washing on the washed product to obtain the coal-based graphitized carbon based on molten salt liquid-phase carbonization.

[0012] Preferably, the particle size of the pulverized coal is above 100.

[0013] Preferably, the concentration of the hydrogen peroxide solution is 10 wt% - 30 wt%.

[0014] Preferably, the pulverized coal uses low-rank coal.

[0015] Preferably, treat the pulverized coal with a hydrogen peroxide solution to obtain a depolymerized precursor product, including:

[0016] Place the pulverized coal in a hydrogen peroxide solution, treat it at 55 - 65 °C for 3 - 9 h, then perform solid-liquid separation, wash until neutral, and dry to obtain the depolymerized precursor product.

[0017] Preferably, the binary eutectic mixed salt uses a KCl / K2CO3 mixed salt or a KCl / Na2CO3 mixed salt.

[0018] Preferably, in the KCl / K2CO3 mixed salt, the mass ratio of KCl to K2CO3 is 2:3;

[0019] In the KCl / Na2CO3 mixed salt, the mass ratio of KCl to Na2CO3 is 3:7.

[0020] Preferably, the mass ratio of the precursor product to the binary eutectic mixed salt is 1:(1 - 10).

[0021] Preferably, performing deashing treatment and washing on the washed product to obtain the coal-based graphitized carbon based on molten salt liquid-phase carbonization includes:

[0022] Perform pickling and water washing treatment on the washed product to deash the washed product; then wash the washed product until neutral and dry to remove moisture to obtain the coal-based graphitized carbon based on molten salt liquid-phase carbonization.

[0023] The present invention also provides a coal-based graphitized carbon based on molten salt liquid-phase carbonization prepared by the above-mentioned preparation method.

[0024] The present invention has the following beneficial effects:

[0025] In the preparation method of coal-based graphitized carbon based on molten salt liquid-phase carbonization of the present invention, a binary eutectic mixed salt is selected as the molten medium, which enhances the reaction activity of coal molecules and significantly increases the specific surface area of the obtained carbon material. At the same time, since the reaction occurs in a liquid-phase environment, it promotes the formation of a graphitized structure. The present invention develops a graphitized structure synergistically while obtaining porous carbon, avoiding many adverse factors of amorphous carbon in practical applications. The present invention adjusts the structure by chemically pre-treating the precursor, thus laying a foundation for the subsequent graphitization. The molten salt used has reaction activity, ensuring that the entire reaction process can be fully carried out in a liquid-phase medium. In addition, the experimental conditions of the present invention are relatively mild, and the selected molten salt is not highly corrosive, reducing the equipment usage requirements. In addition, the used salt can be recycled for secondary use, having indirect economic and environmental benefits. Description of the Drawings

[0026] Figure 1(a) is a comparison diagram of the nitrogen adsorption / desorption curves of the products obtained in Example 1 and Comparative Example 1 of the present invention.

[0027] Figure 1(b) is a comparison diagram of the micropore size distributions of the product HCAC obtained in Example 1 and the product CAC obtained in Comparative Example 1 of the present invention.

[0028] Figure 1(c) is a comparison diagram of the mesopore / macropore size distributions of the product HCAC obtained in Example 1 and the product CAC obtained in Comparative Example 1 of the present invention.

[0029] Figure 2 is a comparison diagram of the microcrystalline structures of the product HCAC obtained in Example 1 and the product CAC obtained in Comparative Example 1 of the present invention. Detailed Embodiments

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components described and shown in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0031] The preparation method of coal-based graphitized carbon based on molten salt liquid-phase carbonization of the present invention includes the following steps:

[0032] Step 1: Using low-rank coal as a carbon source, after crushing and screening, take the undersize material to obtain refined coal powder with a particle size of more than 100.

[0033] Step 2: Place the refined coal powder obtained in Step 1 into a hydrogen peroxide (H2O2) solution with a concentration of 10wt%-30wt%, and treat it at a temperature of 55-65°C for 3-9h to obtain a depolymerized precursor product.

[0034] Step 3: Grind the depolymerized precursor product obtained in Step 2 evenly with a binary eutectic mixed salt according to a mass ratio of 1:(1-10) to obtain a solid-phase mixture. Among them, the binary eutectic mixed salt can be a chloride-oxidizing salt, including KCl / K2CO3 or KCl / Na2CO3. In the KCl / K2CO3 mixed salt, the mass ratio of KCl to K2CO3 is 2:3; in the KCl / Na2CO3 mixed salt, the mass ratio of KCl to Na2CO3 is 3:7.

[0035] Step 4: Transfer the solid-phase mixture obtained in Step 3 to a nickel crucible and place it in a tube furnace. Set the reaction temperature to 850-950°C, and carry out pyrolysis for 2-4h under an inert atmosphere. After the heat preservation is completed, cool it to obtain a pyrolysis product.

[0036] Step 5: Place the pyrolysis product obtained in Step 4 in deionized water for water washing treatment. Wash repeatedly until the salt is fully dissolved, then recover the washing solution and separate to obtain a water-washed product.

[0037] Step 6: Carry out acid washing and water washing treatment on the water-washed product obtained in Step 5 for deep deashing. After the pH becomes neutral, carry out suction filtration and drying to obtain the coal-based graphitized carbon based on molten salt liquid-phase carbonization.

[0038] Example 1

[0039] The preparation method of the coal-based graphitized carbon based on molten salt liquid-phase carbonization in this example includes the following steps:

[0040] Step 1: Using low-rank coal as a carbon source, after crushing and screening, take the undersize material to obtain refined coal powder with a particle size of more than 100.

[0041] Step 2: Place the refined coal powder obtained in Step 1 into a hydrogen peroxide (H2O2) solution with a concentration of 30wt%, and treat it at a temperature of 60°C for 9h to obtain a depolymerized precursor product.

[0042] Step 3: Grind the depolymerized precursor product obtained in Step 2 evenly with a binary eutectic mixed salt according to a mass ratio of 1:8 to obtain a solid-phase mixture. Among them, the binary eutectic mixed salt is KCl / K2CO3, and the mass ratio of KCl to K2CO3 is 2:3.

[0043] Step 4: Transfer the solid-phase mixture obtained in Step 3 to a nickel crucible and place it in a tubular furnace. Set the reaction temperature to 900 °C and pyrolyze it for 2 h under an inert atmosphere. After the heat preservation is completed, cool it to obtain a pyrolysis product.

[0044] Step 5: Place the pyrolysis product obtained in Step 4 in deionized water for water washing treatment. Wash it repeatedly until the salts are fully dissolved, then recover the washing solution and separate to obtain a water-washed product.

[0045] Step 6: Perform pickling and water washing treatment on the water-washed product obtained in Step 5 for deep ash removal. After the pH becomes neutral, perform suction filtration and drying to obtain the coal-based graphitized carbon based on molten salt liquid-phase carbonization.

[0046] As Figure 1(a) - Figure 1(c) shown, the coal-based graphitized carbon based on molten salt liquid-phase carbonization obtained in this example has a specific surface area of 1530.5 m 2 g -1 .

[0047] As Figure 2 shown, it can be seen that the coal-based graphitized carbon obtained in this example based on molten salt liquid-phase carbonization has a graphitized structure, an increased specific surface area of HCAC, and an increased content of micropores / mesopores.

[0048] Comparative Example 1

[0049] The preparation method of the carbon material in this comparative example includes the following steps:

[0050] Step 1: Use low-rank coal as the carbon source. After crushing and screening, take the undersize material to obtain refined coal powder with a particle size of more than 100.

[0051] Step 2: Transfer the refined coal powder obtained in Step 1 to a nickel crucible and place it in a tubular furnace. Set the reaction temperature to 900 °C and pyrolyze it for 2 h under an inert atmosphere. After the heat preservation is completed, cool it to obtain a pyrolysis product.

[0052] Step 5: Place the pyrolysis product obtained in Step 4 in deionized water for water washing treatment. Wash it repeatedly until the salts are fully dissolved, then recover the washing solution and separate to obtain a water-washed product.

[0053] Step 6: Perform pickling and water washing treatment on the water-washed product obtained in Step 5 for deep ash removal. After the pH becomes neutral, perform suction filtration and drying to obtain the carbon material of the example.

[0054] As Figure 1(a) - Figure 1(c) shown, the carbon material of the example obtained in this example has a specific surface area of 1268.7 m 2 g -1 .

[0055] As Figure 2As shown, it can be seen that the carbon material CAC obtained in this comparative example has a smaller specific surface area and a weaker etching degree.

[0056] In summary, as can be seen from the results of Example 1 and the comparative example, the sample precursor depolymerized with a 30 wt% hydrogen peroxide (H2O2) solution for 9 h in Example 1 has a looser structure, a larger specific surface area, a higher porosity, and the obtained HCAC has a specific surface area of 1530.5 m 2 g -1 , which is significantly higher than that of the CAC derived from raw coal in Comparative Example 1 (Figure 1); and the C(002) peak shifts to the right, and the graphitization degree is improved, while the obtained CAC in the comparative example has a smaller specific surface area and a weaker etching degree, as shown in Figure 2 .

[0057] Example 2

[0058] The preparation method of the molten salt liquid-phase carbonized coal-based graphitized carbon in this example includes the following steps:

[0059] Step 1: Using low-rank coal as a carbon source, after crushing and screening, take the undersize material to obtain refined coal powder with a particle size of more than 100.

[0060] Step 2: Place the refined coal powder obtained in Step 1 in a hydrogen peroxide (H2O2) solution with a concentration of 20 wt%, and treat it at a temperature of 60 °C for 9 h to obtain a depolymerized precursor product.

[0061] Step 3: Grind the depolymerized precursor product obtained in Step 2 with a binary eutectic mixed salt in a mass ratio of 1:10 to obtain a solid-phase mixture. Among them, the binary eutectic mixed salt can be KCl / K2CO3, and in the KCl / K2CO3 mixed salt, the mass ratio of KCl to K2CO3 is 2:3.

[0062] Step 4: Transfer the solid-phase mixture obtained in Step 3 to a nickel crucible and place it in a tubular furnace. Set the reaction temperature to 900 °C, and carry out pyrolysis for 3 h under an inert atmosphere. After the heat preservation is completed, cool it to obtain a pyrolysis product.

[0063] Step 5: Place the pyrolysis product obtained in Step 4 in deionized water for water washing treatment. Wash repeatedly until the salt is fully dissolved, then recover the washing liquid and separate to obtain a water-washed product.

[0064] Step 6: Perform acid washing and water washing treatment on the water-washed product obtained in Step 5 to deeply remove ash. After the pH becomes neutral, carry out suction filtration and drying to obtain the molten salt liquid-phase carbonized coal-based graphitized carbon.

[0065] After testing, the specific surface area of the coal-based graphitized carbon obtained in this example is 1470 m 2 g -1 .

[0066] Example 3

[0067] The preparation method of coal-based graphitized carbon based on molten salt liquid-phase carbonization in this example includes the following steps:

[0068] Step 1: Using low-rank coal as the carbon source, after crushing and screening, take the undersize material to obtain refined coal powder with a particle size of more than 100 mesh.

[0069] Step 2: Place the refined coal powder obtained in Step 1 into a hydrogen peroxide (H2O2) solution with a concentration of 15 wt%, and treat it at a temperature of 65 °C for 3 h to obtain a depolymerized precursor product.

[0070] Step 3: Grind the depolymerized precursor product obtained in Step 2 evenly with a binary eutectic mixed salt according to a mass ratio of 1:10 to obtain a solid-phase mixture. Among them, the binary eutectic mixed salt uses KCl / Na2CO3. In the KCl / Na2CO3 mixed salt, the mass ratio of KCl to Na2CO3 is 3:7.

[0071] Step 4: Transfer the solid-phase mixture obtained in Step 3 to a nickel crucible and place it in a tube furnace. Set the reaction temperature to 950 °C, and carry out pyrolysis for 2 h under an inert atmosphere. After the heat preservation is completed, cool it to obtain a pyrolysis product.

[0072] Step 5: Place the pyrolysis product obtained in Step 4 in deionized water for water washing treatment. Wash repeatedly until the salt is fully dissolved, then recover the washing liquid and separate to obtain a water-washed product.

[0073] Step 6: Carry out pickling and water washing treatment on the water-washed product obtained in Step 5 again for deep deashing. After the pH becomes neutral, carry out suction filtration and drying to obtain the coal-based graphitized carbon based on molten salt liquid-phase carbonization.

[0074] After testing, the specific surface area of the coal-based graphitized carbon obtained in this example is 1350 m 2 g -1 .

[0075] Example 4

[0076] The preparation method of coal-based graphitized carbon based on molten salt liquid-phase carbonization in this example includes the following steps:

[0077] Step 1: Using low-rank coal as the carbon source, after crushing and screening, take the undersize material to obtain refined coal powder with a particle size of more than 100 mesh.

[0078] Step 2: Place the refined coal powder obtained in Step 1 into a hydrogen peroxide (H2O2) solution with a concentration of 10 wt%, and treat it at a temperature of 65 °C for 6 h to obtain a depolymerized precursor product.

[0079] Step 3: Grind the depolymerized precursor product obtained in Step 2 evenly with a binary eutectic mixed salt at a mass ratio of 1:6 to obtain a solid-phase mixture. Among them, the binary eutectic mixed salt is KCl / Na2CO3. In the KCl / Na2CO3 mixed salt, the mass ratio of KCl to Na2CO3 is 3:7.

[0080] Step 4: Transfer the solid-phase mixture obtained in Step 3 to a nickel crucible and place it in a tube furnace. Set the reaction temperature to 950 °C and pyrolyze it for 4 h under an inert atmosphere. After the heat preservation is completed, cool it to obtain a pyrolysis product.

[0081] Step 5: Place the pyrolysis product obtained in Step 4 in deionized water for water washing treatment. Wash it repeatedly until the salt is fully dissolved, then recover the washing solution and separate to obtain a water-washed product.

[0082] Step 6: Perform acid washing and water washing treatment on the water-washed product obtained in Step 5 to deeply remove ash. After the pH becomes neutral, perform suction filtration and drying to obtain the coal-based graphitized carbon based on molten salt liquid-phase carbonization.

[0083] After testing, the specific surface area of the coal-based graphitized carbon obtained in this example is 1310 m 2 g -1 .

[0084] Example 5

[0085] The preparation method of the coal-based graphitized carbon based on molten salt liquid-phase carbonization in this example includes the following steps:

[0086] Step 1: Use low-rank coal as the carbon source. After crushing and screening, take the undersize material to obtain refined coal powder with a particle size of more than 100.

[0087] Step 2: Place the refined coal powder obtained in Step 1 in a hydrogen peroxide (H2O2) solution with a concentration of 25 wt%, and treat it at a temperature of 55 °C for 9 h to obtain a depolymerized precursor product.

[0088] Step 3: Grind the depolymerized precursor product obtained in Step 2 evenly with a binary eutectic mixed salt at a mass ratio of 1:5 to obtain a solid-phase mixture. Among them, the binary eutectic mixed salt is KCl / K2CO3. In the KCl / K2CO3 mixed salt, the mass ratio of KCl to K2CO3 is 2:3.

[0089] Step 4: Transfer the solid-phase mixture obtained in Step 3 to a nickel crucible and place it in a tube furnace. Set the reaction temperature to 850 °C and pyrolyze it for 4 h under an inert atmosphere. After the heat preservation is completed, cool it to obtain a pyrolysis product.

[0090] Step 5: Place the pyrolysis product obtained in Step 4 in deionized water for water washing treatment. Wash repeatedly until the salts are fully dissolved, then recover the washing solution and separate to obtain the water-washed product.

[0091] Step 6: Perform pickling and water washing treatment on the water-washed product obtained in Step 5 for deep ash removal. After the pH becomes neutral, perform suction filtration and drying to obtain the coal-based graphitized carbon based on molten salt liquid-phase carbonization.

[0092] After testing, the specific surface area of the coal-based graphitized carbon obtained in this example is 1630 m 2 g -1 .

[0093] Example 6

[0094] The preparation method of the coal-based graphitized carbon based on molten salt liquid-phase carbonization in this example includes the following steps:

[0095] Step 1: Use low-rank coal as the carbon source. After crushing and screening, take the undersize material to obtain refined coal powder with a particle size of more than 100.

[0096] Step 2: Place the refined coal powder obtained in Step 1 in a hydrogen peroxide (H2O2) solution with a concentration of 30 wt%, and treat it at a temperature of 55 °C for 89 h to obtain a depolymerized precursor product.

[0097] Step 3: Grind the depolymerized precursor product obtained in Step 2 evenly with a binary eutectic mixed salt according to a mass ratio of 1:3 to obtain a solid-phase mixture. Among them, the binary eutectic mixed salt uses KCl / K2CO3, and in the KCl / K2CO3 mixed salt, the mass ratio of KCl to K2CO3 is 2:3.

[0098] Step 4: Transfer the solid-phase mixture obtained in Step 3 to a nickel crucible and place it in a tube furnace. Set the reaction temperature to 850 °C, and perform pyrolysis for 3 h under an inert atmosphere. After the heat preservation ends, cool to obtain a pyrolysis product.

[0099] Step 5: Place the pyrolysis product obtained in Step 4 in deionized water for water washing treatment. Wash repeatedly until the salts are fully dissolved, then recover the washing solution and separate to obtain the water-washed product.

[0100] Step 6: Perform pickling and water washing treatment on the water-washed product obtained in Step 5 for deep ash removal. After the pH becomes neutral, perform suction filtration and drying to obtain the coal-based graphitized carbon based on molten salt liquid-phase carbonization.

[0101] After testing, the specific surface area of the coal-based graphitized carbon obtained in this example is 1210 m 2 g -1 .

[0102] Example 7

[0103] The preparation method of coal-based graphitized carbon based on molten salt liquid-phase carbonization in this embodiment includes the following steps:

[0104] Step 1: Using low-rank coal as a carbon source, after crushing and screening, the undersize material is taken to obtain refined coal powder with a particle size of more than 100.

[0105] Step 2: The refined coal powder obtained in Step 1 is placed in a hydrogen peroxide (H2O2) solution with a concentration of 30 wt%, and treated at a temperature of 60 °C for 4 h to obtain a depolymerized precursor product.

[0106] Step 3: The depolymerized precursor product obtained in Step 2 is ground evenly with a binary eutectic mixed salt according to a mass ratio of 1:1 to obtain a solid-phase mixture. Among them, the binary eutectic mixed salt uses KCl / Na2CO3. In the KCl / Na2CO3 mixed salt, the mass ratio of KCl to Na2CO3 is 3:7.

[0107] Step 4: Transfer the solid-phase mixture obtained in Step 3 to a nickel crucible and place it in a tube furnace. Set the reaction temperature to 850 °C, and carry out pyrolysis for 2 h under an inert atmosphere. After the heat preservation is completed, it is cooled to obtain a pyrolysis product.

[0108] Step 5: The pyrolysis product obtained in Step 4 is placed in deionized water for water washing treatment. After repeated washing to fully dissolve the salt, the washing solution is recovered, and the washed product is separated.

[0109] Step 6: The washed product obtained in Step 5 is subjected to acid washing and water washing treatment again for deep ash removal. After the pH becomes neutral, filtration and drying are carried out to obtain the coal-based graphitized carbon based on molten salt liquid-phase carbonization.

[0110] After testing, the specific surface area of the coal-based graphitized carbon obtained in this embodiment is 980 m 2 g -1 .

[0111] As can be seen from the above experimental results, the present invention uses a binary eutectic mixture of chloride salt / oxidizing salt as a liquid-phase reaction medium, and by modulating the sp 2 - / sp 3The "solvent" effect of molten salt is unlocked by the -C ratio to obtain coal-based graphitized porous carbon. While obtaining porous carbon, the present invention also synergistically develops a graphitized structure, avoiding many adverse factors of amorphous carbon in practical applications. In addition, the present invention adjusts the structure by chemically pre-treating the precursor, thus laying a foundation for the subsequent graphitization; the molten salt used has reaction activity, ensuring that the entire reaction process can be fully carried out in a liquid phase medium. The present invention selects a combination of chloride salt / oxidizing salt as the molten medium, enhancing the reaction activity of coal molecules and significantly increasing the specific surface area of the obtained carbon material; at the same time, since the reaction occurs in a liquid phase environment, it promotes the formation of a graphitized structure. The experimental conditions of the present invention are relatively mild, and the selected molten salt does not have strong corrosiveness, reducing the equipment usage requirements; in addition, the used salt can be recycled for secondary use, having indirect economic and environmental benefits.

[0112] Obviously, the described embodiments are only partial embodiments of the present invention, rather than all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0113] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent substitutions can still be made to the specific implementation manners of the present invention, and any modification or equivalent substitution without departing from the spirit and scope of the present invention shall be covered by the scope of the present invention.

Claims

1. A preparation method of coal-based graphitized carbon based on molten salt liquid-phase carbonization, characterized in that, It includes the following processes: Treat pulverized coal with hydrogen peroxide solution to obtain a depolymerized precursor product; Mix the precursor product with a binary eutectic mixed salt to obtain a solid-phase mixture; Pyrolyze the solid-phase mixture in an inert atmosphere at 850 - 950 °C for 2 - 4 h to obtain a pyrolysis product; Wash the pyrolysis product to dissolve the binary eutectic mixed salt in the pyrolysis product to obtain a washed product; Perform deashing treatment and washing on the washed product to obtain the molten-salt liquid-phase carbonization-based coal-based graphitized carbon; 2. The preparation method of a coal-based graphitized carbon based on molten salt liquid-phase carbonization according to claim 1, characterized in that, The particle size of the pulverized coal is above 100; 3. The preparation method of a coal-based graphitized carbon based on molten salt liquid-phase carbonization according to claim 1, characterized in that, The concentration of the hydrogen peroxide solution is 10 wt% - 30 wt%; 4. The preparation method of a coal-based graphitized carbon based on molten salt liquid-phase carbonization according to claim 1, wherein, The pulverized coal uses low-rank coal; 5. A preparation method of a coal-based graphitized carbon based on molten salt liquid-phase carbonization according to any one of claims 1-4, characterized in that, Treat pulverized coal with hydrogen peroxide solution to obtain a depolymerized precursor product, including: Place the pulverized coal in hydrogen peroxide solution, treat it at 55 - 65 °C for 3 - 9 h, then perform solid-liquid separation, wash until neutral, and dry to obtain the depolymerized precursor product; 6. The preparation method of a coal-based graphitized carbon based on molten-salt liquid-phase carbonization according to claim 1, characterized in that, The binary eutectic mixed salt uses KCl / K2CO3 mixed salt or KCl / Na2CO3 mixed salt; 7. The preparation method of a coal-based graphitized carbon based on molten salt liquid-phase carbonization according to claim 6, characterized in that, In the KCl / K2CO3 mixed salt, the mass ratio of KCl to K2CO3 is 2:3; In the KCl / Na2CO3 mixed salt, the mass ratio of KCl to Na2CO3 is 3:7; 8. The preparation method of coal-based graphitized carbon based on molten salt liquid-phase carbonization according to claim 1, characterized in that, The mass ratio of the precursor product to the binary eutectic mixed salt is 1:(1 - 10); 9. The preparation method of coal-based graphitized carbon based on molten salt liquid-phase carbonization according to claim 1, characterized in that, Perform deashing treatment and washing on the washed product to obtain the molten-salt liquid-phase carbonization-based coal-based graphitized carbon, including: Perform pickling and water washing treatment on the washed product to deash the washed product; then wash the washed product until neutral and dry to remove moisture to obtain the molten-salt liquid-phase carbonization-based coal-based graphitized carbon; 10. A molten-salt liquid-phase carbonization-based coal-based graphitized carbon prepared by the preparation method according to any one of claims 1 - 9.

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