A method for preparing a material for energy storage

Abstract

The application provides a preparation method of energy storage material, comprising the following steps: step 1, component cutting of raw oil to obtain light components and heavy components; step 2, coking treatment of the light components to obtain coke; step 3, mixing of the coke obtained in step 2 and the heavy components, and then carbonization treatment and graphitization treatment to obtain the energy storage material. The raw oil is first divided into light components and heavy components, the light components are used to prepare coke, and the heavy components are used to coat the coke, so that the quality of the core can be improved, the invalid components can be used as coating materials, the raw material can be fully utilized, and the effect of coating is better due to the same origin of the core and the shell.

Description

Technical Field

[0001] This invention belongs to the field of new energy carbon materials, specifically relating to a method for preparing materials for energy storage. Background Technology

[0002] The energy crisis is one of the major problems facing society today.

[0003] The performance of graphite anode materials with a "core-shell" structure used in batteries largely depends on the properties of the raw material coke. However, existing technologies generally start with petroleum coke in the preparation of anode materials, which is powerless to adjust the structure of coke or requires a lot of manpower and resources to evaluate the properties and structure of coke. This greatly restricts the standardization and efficiency of the industry.

[0004] In addition, coke production plants currently employ two methods to produce coke: production using all raw materials and production by enriching effective components. The former makes it difficult to guarantee coke quality, firstly due to fluctuations in raw materials, and secondly because ineffective components affect product performance. The latter, by enriching effective components, significantly improves coke quality, but ineffective components, as byproducts, often have difficult disposal options and can only be treated as fuel or hazardous waste, greatly reducing the utilization rate of feedstock oil.

[0005] CN113697806A relates to a liquid-phase mechanical fusion coated artificial graphite material and its preparation method. The method involves: first, mechanically pulverizing petroleum coke raw material, then improving its morphology and removing fine powder using a shaping machine to obtain a shaped powder; subjecting the shaped powder to high-temperature heat treatment to obtain artificial graphite material A; taking artificial graphite material A and adding a liquid-phase coating agent, stirring and mixing to obtain artificial graphite material B; subjecting artificial graphite material B to low-temperature heat treatment and then crushing and shaping to obtain artificial graphite material C; placing artificial graphite material C into a container and placing it in a carbonization kiln for high-temperature treatment, then cooling it to room temperature for crushing and grading to obtain the liquid-phase mechanical fusion coated artificial graphite material. The liquid-phase coating method not only results in uniform mixing and non-sticking, but also significantly reduces the emission of toxic and harmful gases. Simultaneously, the prepared material achieves a reversible capacity of 355 mAh / g, an initial efficiency of over 94%, good compatibility with electrolytes, and a significant decrease in internal resistance. However, the compatibility between the coating agent and the host material needs improvement.

[0006] CN113912054A discloses a method for preparing artificial graphite anode material. The method involves crushing and purifying coke powder, followed by shaping to control the D50 of the shaped coke powder to 10±2 μm. The shaped coke powder is then graphitized using a multi-stage heating process to obtain an intermediate product of artificial graphite anode material. This intermediate product is then mixed with a coating material at a ratio of 100:1-100:5 and carbonized in a carbonization furnace at a temperature not exceeding 1100℃. Finally, the product is sieved to obtain artificial graphite anode material with D10 = 6±1 μm, D50 = 10±2 μm, D90 ≤ 30 μm, and D100 ≤ 40 μm. While this method improves the rate performance of the material by crushing and shaping the coke powder and mixing the coating material with the artificial graphite anode material in a specific ratio, the process is lengthy, involves complex influencing factors, and is difficult to maintain stable production.

[0007] CN111620331A relates to an artificial graphite anode material, its preparation method, and its application in lithium-ion batteries. The method includes the following steps: (1) mixing petroleum coke particles, resin, and dispersant, stirring and heating to obtain secondary petroleum coke particles; (2) mixing the secondary petroleum coke particles with calcined needle coke particles to obtain an artificial graphite precursor; (3) subjecting the artificial graphite precursor to a graphitization process to obtain the artificial graphite anode material. This invention employs a coating method with strong repeatability, which can be used for continuous production, and the process is stable and easy to control. The graphite anode material obtained by this invention has advantages such as excellent cycle performance, continuous production capability, high production efficiency, stable graphite crystal structure at the furnace, and small specific surface area. However, this invention controls the capacity of the artificial graphite anode material by controlling the mixing ratio of petroleum coke and needle coke. Selecting the formula is time-consuming and labor-intensive. In addition, the price of needle coke is relatively high, which is not conducive to reducing costs.

[0008] CN113353915A discloses a mesophase carbon microsphere, its preparation method, and spherical porous activated carbon material and its applications. The method involves pre-oxidizing nanoscale petroleum coke powder with an oxidant to obtain oxidized petroleum coke powder. The oxidized petroleum coke powder, ethylene tar, and raw material pitch are added to a high-pressure reactor, where the oxidized petroleum coke acts as a nucleating agent and the ethylene tar acts as a viscosity modifier. Under an inert gas atmosphere, thermal polycondensation is performed to obtain mesophase pitch. The obtained mesophase pitch is separated using Soxhlet extraction to obtain mesophase carbon microspheres. A mixture of the obtained mesophase carbon microspheres and an alkaline reagent is subjected to high-temperature thermal pyrolysis treatment, and alkaline etching is used to form a multi-level pore structure, resulting in a high-performance porous spherical carbon material. This preparation method can effectively control the particle size and particle size distribution of the spherical carbon material, effectively improving the energy density of the energy storage material. The preparation conditions are easy to control, and continuous production is easily achieved. However, while the pore-forming effect can significantly increase the specific surface area, the initial efficiency and cycle performance may be affected, reducing the overall performance of the energy storage material.

[0009] Therefore, further research is needed in this field on the preparation of anode materials. Summary of the Invention

[0010] The main objective of this invention is to provide a method for preparing energy storage materials, so as to overcome the shortcomings of existing technologies, such as high preparation cost and poor core and shell coating effect.

[0011] To achieve the above objectives, the present invention provides a method for preparing an energy storage material, comprising the following steps:

[0012] Step 1: The raw oil is fractionated to obtain light and heavy components;

[0013] Step 2: The light components are coked to obtain coke;

[0014] Step 3: Mix the coke obtained in Step 2 with the heavy components, and then perform carbonization and graphitization treatments to obtain energy storage materials.

[0015] In one embodiment of the method for preparing energy storage materials according to the present invention, the feed oil is at least one of catalytic slurry oil, ethylene tar, furfural extract oil, coking wax oil, catalytic cycle oil, deoiled pitch, and hydrogenated residue oil.

[0016] In one embodiment of the method for preparing energy storage materials according to the present invention, the softening point of the heavy components is 60-280℃.

[0017] In one embodiment of the method for preparing energy storage materials according to the present invention, the coking treatment is one of delayed coking, batch coking, and fluidized coking; the coking temperature is 430-510℃, the pressure is 0.1-0.7MPa, and the cycle ratio is 0-0.6.

[0018] In one embodiment of the method for preparing energy storage materials according to the present invention, step 2 further includes a step of crushing and sieving the coke, wherein the particle size D50 of the coke after sieving is 5-15 μm.

[0019] In one embodiment of the method for preparing energy storage materials according to the present invention, the coke obtained in step 2 is mixed with heavy components in a mass ratio of 100:1-100:30, preferably 100:5-100:20.

[0020] In one embodiment of the method for preparing energy storage materials according to the present invention, the carbonization process includes two stages: the temperature of the first stage is from room temperature to 400°C, and the temperature of the second stage is from 400°C to 1000°C.

[0021] In one embodiment of the method for preparing energy storage materials according to the present invention, the carbonization process is carried out in an atmosphere furnace, a calcining furnace, a coating kettle, or a fluidized bed reactor.

[0022] In one embodiment of the method for preparing energy storage materials according to the present invention, the graphitization treatment is performed by intermittent graphitization, semi-continuous graphitization, or continuous graphitization.

[0023] In one embodiment of the method for preparing energy storage materials according to the present invention, the graphitization treatment temperature is 2600-3000℃ and the graphitization treatment time is not less than 20 hours.

[0024] The beneficial effects of this invention are:

[0025] (1) According to the "carbonaceous mesophase theory", the higher the mesophase content, the higher the graphitization degree of the feedstock coke, and the higher the specific capacity of the anode material; the smaller the volume of the mesophase and the closer it is to a sphere, the better the isotropy of the feedstock coke, and the better the cycle life and rate capability of the anode material. In this invention, the feedstock oil is first divided into light components and heavy components. The light components are used to prepare coke, and the heavy components are used as coating materials to coat the coke. This not only improves the quality of the core, but also allows the ineffective components to be used as a coating layer, so as to make full use of the feedstock.

[0026] (2) The recombinant components of the present invention form a uniform core-shell structure with high isotropy in the presence of coke powder, and the coating effect is better due to the homogeneity of the core and shell. Attached Figure Description

[0027] Figure 1This is a process flow diagram of the preparation of energy storage materials according to one embodiment of the present invention. Detailed Implementation

[0028] The technical solution of the present invention will be described in detail below. The following embodiments are implemented under the premise of the technical solution of the present invention and a detailed implementation process is given. However, the protection scope of the present invention is not limited to the following embodiments. Structures or experimental methods that do not specify specific conditions in the following embodiments are generally performed under conventional conditions.

[0029] This invention provides a method for preparing an energy storage material, comprising the following steps:

[0030] Step 1: The raw oil is fractionated to obtain light and heavy components;

[0031] Step 2: The light components are coked to obtain coke;

[0032] Step 3: Mix the coke obtained in Step 2 with the heavy components, and then perform carbonization and graphitization treatments to obtain energy storage materials.

[0033] The energy storage material of this invention can be a graphite anode material used in batteries, such as lithium batteries or sodium batteries, with a core-shell-like structure. The heavy components are on the outside, and coke is on the inside. Because the heavy components are relatively small, mixing them evenly can achieve a thin outer shell structure around the coke. This invention organically combines the anode material preparation process with the coke production process for the core structure, enhancing upstream and downstream integration, simplifying the material preparation process, and reducing production costs.

[0034] Furthermore, this invention separates the feedstock oil into light and heavy components, using the light components to prepare coke and the heavy components as coating materials. This not only improves the quality of the core structure but also allows ineffective components to be used as a coating layer, ensuring full utilization of the feedstock. Simultaneously, due to the homogeneity of the core and shell, the coating effect is superior, overcoming the core-shell coating limitations of existing technologies.

[0035] This invention does not impose any particular limitation on the feedstock oil; any general heavy oil feedstock is acceptable. This includes, but is not limited to, one or more components selected from catalytic slurry oil, ethylene tar, furfural extract oil, coking wax oil, catalytic cycle oil, deoiled pitch, and hydrogenated residue oil.

[0036] The present invention does not impose any particular limitation on the process of component cutting of raw oil, including but not limited to distillation cutting, solvent extraction, etc. The distillation cutting temperature is 450℃-550℃, and the softening point of heavy components is controlled at 60-280℃, preferably 100-250℃.

[0037] Light components are coked to obtain coke. Coking methods include, but are not limited to, delayed coking, batch coking, and fluidized coking. The coking reaction temperature can be constant temperature operation or variable temperature operation, with the temperature controlled at 430-510℃. The pressure is controlled at constant pressure operation or variable pressure operation, with a range of 0.1-0.7MPa and a recycle ratio of 0-0.6.

[0038] In one embodiment, the preparation method of the energy storage material of the present invention further includes crushing and sieving the coke prepared above. The crushing method is not limited and can be either mechanical milling or air jet milling. The particle size D50 is controlled within the range of 5-15 μm.

[0039] Then, the coke is mixed evenly with the above-obtained heavy components and carbonized. The mixing method includes, but is not limited to, one or a combination of several forms such as a stirred tank, a fusion machine, an online mixer, or a fluidized bed reactor. The carbonization process includes, but is not limited to, traditional atmosphere furnaces, calcining furnaces, coated tanks, or fluidized bed reactors. Preferably, the carbonization temperature rise is two-stage, with the first stage at room temperature to 400°C and the second stage at 400-1000°C.

[0040] The mass ratio of coke to the heavy components obtained above is 100:1-100:30, preferably 100:5-100:20.

[0041] Next, the carbonized products are graphitized to obtain energy storage materials. Graphitization can be performed intermittently, semi-continuously, or continuously, with a graphitization temperature of 2600-3000°C and a graphitization time of at least 20 hours. These energy storage materials can be used as anode materials for lithium-ion and sodium-ion batteries, exhibiting high capacity and initial efficiency, excellent rate performance, and superior overall performance. More importantly, the integrated upstream and downstream process reduces manufacturing processes, shortens the workflow, and lowers costs.

[0042] In one specific embodiment, the process flow of the energy storage material of the present invention is as follows: Figure 1 As shown, the feedstock oil is cut into light component A and heavy component B. Light component A is coked to produce high-quality coke C. Coke C is crushed and screened to obtain material D. Material D is fully fused with heavy component B and carbonized to produce material E. Material E is graphitized to obtain energy storage material F.

[0043] Therefore, this invention provides a method for preparing energy storage materials. Starting with the selection of carbon sources and the control of core-layer coke microcrystals, this invention selects specific light components of the feedstock oil as raw materials for coke preparation. According to the "carbonaceous mesophase" theory, the higher the mesophase content, the higher the graphitization degree of the feedstock coke, and the higher the specific capacity of the anode material; the smaller the volume of the mesophase and the closer it is to a sphere, the better the isotropy of the feedstock coke, and the better the cycle life and rate capability of the anode material. Therefore, the anode material prepared by the method of this invention has both high charge / discharge capacity and high-rate charge / discharge capability, as well as good high and low temperature performance.

[0044] Furthermore, the preparation of anode materials requires four major processes—crushing, granulation, graphitization, and sieving—as well as numerous smaller processes. It also involves the selection of coke feedstock and the preparation of coating pitch, resulting in a lengthy process. This invention addresses this complexity by introducing an integrated upstream and downstream concept, extending anode material preparation to feedstock oil. It comprehensively utilizes the light components of the feedstock oil, which have good properties and can serve as feedstock for high-quality coke, while the heavy components, with their high molecular weight and high carbon yield, are suitable for producing coating pitch. This saves costs associated with heavy component processing in refineries, coating pitch production, and a series of advantages from integrated equipment. Overall, preliminary calculations indicate a cost reduction of over 5% in anode material production.

[0045] More importantly, based on the heterogeneous nucleation mechanism, the present invention enables the heavy component B to form a uniform core-shell structure with high isotropy in the presence of coke powder. Due to the homogeneity of the core and shell, the coating effect is better.

[0046] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0047] Example 1

[0048] A refinery purified oil slurry was distilled and cut at a temperature of 520℃ to separate a light component A (boiling point <520℃) and a heavy component B (boiling point >520℃). Light component A underwent delayed coking with a programmed temperature increase of 430-500℃, a pressure of 0.6 MPa, a circulation ratio of 0.4, and a reaction time of 36 hours to produce coke C. Coke C was then pulverized and sieved by an air jet mill to obtain material D, with a particle size controlled between D50 and 7 μm. Heavy component B and material D were mixed uniformly in a coated reactor at a mass ratio of 10:100 under a nitrogen atmosphere at 100℃. The mixture underwent two programmed temperature increases: 100-400℃ with a heating power set at 60% of the total power for 1 hour, and 400-700℃ with a heating power of 60% for 3 hours, resulting in carbonization to obtain material E. After graphitization treatment (temperature 2600-3000℃) for at least 20 hours, energy storage material F was obtained. The properties of raw materials and materials at each stage are shown in Tables 1 and 2:

[0049] Table 1. Basic Properties of Purified Oil Slurry and Cutting Components

[0050]

[0051] Table 2. Analysis of Basic Properties of Coke

[0052] Analysis Project Purified oil slurry coke after coking Light component A coke after coking Yield, % 26.5 30 <![CDATA[True density of coke, g / cm 3 > 1.4156 1.4169 IG / ID 0.46 0.57 <![CDATA[True density of calcined coke, g / cm 3 > 2.0986 2.12

[0053] From the perspective of the effect of distillation and cutting, Example 1 is equivalent to increasing the content of effective components - aromatics and reducing ineffective components - gums and asphaltenes. Under the same coking process conditions, the true density of light component A after cutting is increased compared with the coke prepared from the raw material before cutting. At the same time, the Raman spectrum IG / ID, which represents the degree of regularity of the coke microstructure, increases.

[0054] Comparative Example 1

[0055] The coke obtained from the delayed coking of purified oil slurry in Example 1 was pulverized and sieved by an air jet mill to obtain material d, with the particle size controlled between D50 and 7μm. Material d was mixed with commercially available coated asphalt with a softening point of 150℃ at a mass ratio of 100:5 in a coated autoclave under N2 atmosphere at 100℃. The temperature was increased in two stages: 100-400℃, with the heating power set at 60% of the total power, and held for 1 hour; 400-700℃, with the heating power at 60%, and held for 3 hours. Carbonization was then carried out to obtain material e. After graphitization treatment (temperature 2600-3000℃) for no less than 20 hours, energy storage material f was obtained.

[0056] Example 2

[0057] Ethylene tar from a refinery undergoes solvent deasphalting, using n-butane as the solvent at a ratio of 6:1, at a temperature of 80℃, a pressure of 3.5 MPa, and a residence time of 20 min. This process separates the tar into light component A and heavy component B. Light component A is then subjected to a batch coking process with a programmed temperature increase of 430-500℃, a pressure of 0.6 MPa, and a reaction time of 36 h, producing coke C. Coke C is then pulverized and sieved by an air jet mill to obtain material D, with a particle size controlled between D50 and 7 μm. Heavy component B and material D are mixed uniformly in a coated reactor at a ratio of 10:100 under a nitrogen atmosphere at 100℃. The mixture undergoes two stages of programmed temperature increases: 100-400℃ with a heating power set at 60% of the total power, held for 1 h; and 400-700℃ with a heating power of 60%, held for 3 h, resulting in carbonization and material E. After graphitization treatment (temperature 2600-3000℃) for at least 20 h, energy storage material F is obtained. The properties of each material are shown in Tables 3 and 4:

[0058] Table 3 Properties of Ethylene Tar and Light Heavy Components

[0059]

[0060] Table 4. Analysis of Basic Properties of Coke

[0061] Analysis Project Coke after ethylene tar coking Light component A coke after coking Yield, % 36 29 <![CDATA[True density of coke, g / cm 3 > 1.3956 1.4096 IG / ID 0.43 0.49 <![CDATA[True density of calcined coke, g / cm 3 > 2.0856 2.10

[0062] Comparative Example 2

[0063] The coke obtained from the coking of ethylene tar in Example 2 was pulverized and sieved by an air jet mill to obtain material d, with the particle size controlled between D50 and 7μm. Material d was mixed with commercially available coated asphalt with a softening point of 200℃ at a mass ratio of 100:5 in a coated autoclave under N2 atmosphere at 100℃. The temperature was increased in two stages: 100-400℃, with the heating power set at 60% of the total power, and held for 1 hour; 400-700℃, with the heating power at 60%, and held for 3 hours. Carbonization was then carried out to obtain material e. After graphitization treatment (temperature 2600-3000℃) for no less than 20 hours, energy storage material f was obtained.

[0064] Example 3

[0065] A refinery's hydroreducing process separates slag into light component A and heavy component B through solvent deasphalting. The solvent deasphalting process uses n-butane as the solvent, with a solvent-to-oil ratio of 8, a temperature of 90℃, a pressure of 3.5 MPa, and a residence time of 20 min. Light component A then undergoes a delayed coking process with a programmed temperature increase of 430-500℃, a pressure of 0.6 MPa, a recycle ratio of 0.4, and a reaction time of 36 h, producing coke C. Coke C is then pulverized and sieved using an air jet mill. Material D, with a particle size controlled between D50 and 7 μm, is mixed with heavy component B at a ratio of 10:100 in a coated reactor under N2 atmosphere at 100°C. The mixture undergoes two temperature programs: 100-400°C at 60% heating power for 1 hour, and 400-700°C at 60% heating power for 3 hours, resulting in carbonization and material E. After graphitization (temperature 2600-3000°C) for at least 20 hours, energy storage material F is obtained. The properties of each material are shown in Tables 5 and 6.

[0066] Table 5 Properties of Hydrogenation Slag Reduction and Light and Heavy Components

[0067]

[0068] Table 6. Analysis of Basic Properties of Coke

[0069]

[0070]

[0071] Comparative Example 3

[0072] The coke obtained from the hydrotreated coking process in Example 3 was pulverized and sieved by an air jet mill to obtain material d, with a particle size controlled between D50 and 7 μm. Material d was mixed with commercially available coated asphalt with a softening point of 150°C at a ratio of 100:5 in a coated autoclave under a N2 atmosphere at 100°C. The mixture was then subjected to two temperature programs: 100-400°C with a heating power of 60% of the total power, held for 1 hour; and 400-700°C with a heating power of 60%, held for 3 hours. After natural cooling, the mixture was transferred to an atmosphere furnace and carbonized by raising the temperature from 70°C to 400°C in 1 hour, holding for 2 hours, and then raising the temperature from 400°C to 1000°C in 3 hours to obtain material e. After graphitization treatment (temperature 2600-3000°C) for at least 20 hours, energy storage material f was obtained.

[0073] Comparative Example 4

[0074] The mass ratio of heavy component B to material D in Example 1 was changed to 3:100. The mixture was uniformly mixed in a coated reactor under N2 atmosphere at 100°C. The temperature was increased in two stages: 100-400°C with a heating power of 60% for 1 hour, and 400-700°C with a heating power of 60% of the total power for 3 hours. Carbonization was then carried out to obtain material E. After graphitization treatment (temperature 2600-3000°C) for no less than 20 hours, energy storage material F was obtained.

[0075] The energy storage materials obtained in the examples and comparative examples were mixed with Super P conductive carbon black and PVDF (polyvinylidene fluoride) at a mass ratio of 9:0.5:0.5 to prepare a negative electrode sheet. This negative electrode sheet was then assembled with lithium metal foil and a separator to form a half-cell, and its electrochemical performance was tested using the following methods:

[0076] Lithium intercalation capacity and initial coulombic efficiency test: 0.05C discharge to 5mV, stand for 2 min; 0.01C discharge to 5mV, stand for 2 min; 0.1C charge to 1.5V, stand for 2 min.

[0077] Cyclic performance test: Discharge at 0.2C to 5mV, rest for 2 minutes; charge at 0.2C to 1.5V, rest for 2 minutes. Cycle 500 times.

[0078] Rate performance test: Discharge at 0.5C to 5mV and let stand for 2 minutes; charge at 0.5C to 1.5V and let stand for 2 minutes.

[0079] The test results are shown in Table 7.

[0080] Table 7 Electrochemical properties of materials

[0081]

[0082] As shown in Table 7, the materials prepared in the examples all have better electrochemical performance than those prepared in the corresponding comparative examples. This conclusion corresponds to the properties of coke in Tables 2, 4, and 6. The coke obtained by coking the raw oil after cutting treatment has a more regular microstructure, higher true density, and is more inclined to an ordered structure. Therefore, the batteries prepared in the examples have a higher specific capacity.

[0083] In the embodiments, the coating material and the core layer of the negative electrode material are derived from the same raw material oil, which has better compatibility and coating effect. The higher first efficiency also indicates better coating uniformity, excellent cycle performance and rate performance, and good matching with the performance of coke.

[0084] Furthermore, as can be seen from Example 1 and Comparative Example 4, changing the ratio of coke to heavy component coating material results in different coating effects. The effects of reducing the coating component are shown in Table 7. The initial coulombic efficiency, cycle performance, and rate performance are all poor. This is likely due to the fact that the coating amount of heavy component does not form a complete shell. Therefore, the coating material for heavy component should be within an appropriate range.

[0085] The electrochemical performance of coke produced from different feedstocks varies greatly when it is made into anode materials. Therefore, it is important to pay attention to the selection of anode feedstocks. Different application scenarios have different requirements for anode materials, and feedstock oils and cokes should be customized according to needs.

[0086] In summary, this invention firstly organically combines the anode material preparation process with the upstream coke raw material preparation process, employing an intensive equipment and process layout to efficiently utilize petroleum resources and significantly reduce investment and costs. Secondly, this process emphasizes the control of the quality of the anode raw material coke, controlling the composition and process conditions from the carbon source to achieve the effect of regulating the microstructure of coke, thereby better improving the electrochemical performance of the anode. Thirdly, in terms of the anode material preparation process, using native heavy components as a carrier for forming a stable SEI film, which can be well matched with coke, significantly improves the first-efficiency, cycle performance, and rate performance of the anode material, maximizing the role of coke and producing a product with superior performance.

[0087] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing an energy storage material, characterized in that, Includes the following steps: Step 1: The raw oil is fractionated to obtain light components and heavy components; the softening point of the heavy components is 60-280℃. Step 2: The light components are coked to obtain coke; Step 3: Mix the coke obtained in Step 2 with the heavy components obtained in Step 1 at a mass ratio of 100:5-100:20, and then perform carbonization and graphitization treatments to obtain energy storage materials. The feedstock oil is one or a combination of several of the following: catalytic slurry oil, ethylene tar, furfural extract oil, coking wax oil, catalytic circulating oil, deoiled asphalt, and hydrogenated residue oil.

2. The method for preparing energy storage materials according to claim 1, characterized in that, The coking process is one of delayed coking, batch coking, or fluidized bed coking; the coking temperature is 430-510℃, the pressure is 0.1-0.7MPa, and the cycle ratio is 0-0.

6.

3. The method for preparing energy storage materials according to claim 1, characterized in that, Step 2 also includes the step of crushing and sieving the coke, wherein the particle size D50 of the coke after sieving is 5-15 μm.

4. The method for preparing energy storage materials according to claim 1, characterized in that, The carbonization process includes two stages: the temperature of the first stage is from room temperature to 400°C, and the temperature of the second stage is from 400°C to 1000°C.

5. The method for preparing energy storage materials according to claim 1, characterized in that, The carbonization process is carried out in an atmosphere furnace, calcination furnace, coating kettle, or fluidized bed reactor.

6. The method for preparing energy storage materials according to claim 1, characterized in that, The graphitization process can be intermittent graphitization, semi-continuous graphitization, or continuous graphitization.

7. The method for preparing energy storage materials according to claim 1, characterized in that, The graphitization treatment temperature is 2600-3000℃, and the graphitization treatment time is no less than 20 hours.

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