Coated asphalt and preparation method thereof

Abstract

The invention relates to the field of lithium ion battery negative electrode materials, and discloses coated asphalt and a preparation method thereof.The preparation method comprises the steps that ethylene tar and catalytic slurry oil are sequentially subjected to mixing, sedimentation and heating treatment, and a pretreatment product is obtained; sequentially carrying out oxidation cross-linking catalytic reaction and polycondensation catalytic reaction on the pretreated product to obtain a crude asphalt product; the crude asphalt product is extracted, the coated asphalt is obtained, the temperature of the oxidation cross-linking catalytic reaction is 250-320 DEG C, and the time is 3-5 h; the temperature of the polycondensation catalytic reaction is 320-360 DEG C, and the time is 6-10 hours; the catalyst for the oxidation crosslinking catalytic reaction comprises vinyltriethoxysilane or dicumyl peroxide. The actual specific capacity and the cycling stability of the battery negative electrode material can be improved.

Description

Technical Field

[0001] The present invention relates to the field of lithium ion battery negative electrode materials, and in particular to coated asphalt and a preparation method thereof. Background Art

[0002] Among the many negative electrode materials, graphite has become the most commercially valuable negative electrode material for lithium-ion batteries due to its high specific capacity, good cycle performance, low lithium insertion and extraction platform, and low cost. However, due to the poor compatibility of graphite with organic solvent electrolytes, excessive SEI film will form on its surface during the charge and discharge process. Excessive SEI film will not only lead to irreversible loss of lithium battery capacity, but may even cause the graphite layer to dissociate and even peel off, resulting in a further decrease in battery capacity and cycle performance. In order to solve this problem, it is usually necessary to modify and modify the graphite material. Among the modification methods, modifying the graphite material with asphalt coating is a relatively effective method.

[0003] After the negative electrode material of the lithium battery is modified by coating asphalt, the electrochemical performance of the negative electrode material will be significantly improved, such as the first coulombic efficiency, specific capacity and cycle stability. In the existing market, commercial lithium battery negative electrode materials require that the coated asphalt needs to have a high softening point (≥250 degrees) and a coking value (≥70%), as well as a low quinoline insoluble content (≤2%). At the same time, it is also necessary to ensure that the prepared asphalt product has a high yield (≥20%). Asphalt with a high softening point has a low light component content and a high coking value. After high-temperature carbonization and cracking, it can form a dense amorphous carbon layer on the graphite surface to reduce the direct contact between the graphite surface and the electrolyte, thereby effectively reducing the irreversible capacity during the first charge and discharge process of the lithium battery. In addition, a lower quinoline insoluble content can make the asphalt tend to form an isotropic structure, which is beneficial to improving the coating effect of asphalt on the graphite material.

[0004] In this regard, the prior art has made many attempts in the research of coated asphalt. Patent CN109233305A flash-separates soft asphalt and then adds coumarone resin to obtain coated asphalt with low quinoline insoluble content. However, the softening point of the coated asphalt prepared is 110 to 140 degrees. The lower softening point cannot meet the performance requirements of high-softening-point asphalt. Patent CN103897714A and patent CN101108918A respectively use a two-stage high-temperature negative pressure oxidation method and a method of adding additives to medium-temperature coal tar and heat treatment to prepare high-softening-point coated asphalt, but the quinoline insoluble content is higher than 10%. In addition, the use of high temperature to prepare asphalt is often accompanied by a lower yield. At present, the prior art has not completely solved the problem of meeting commercial requirements for indicators such as asphalt softening point, coking value, quinoline insoluble content and yield.

[0005] Therefore, the above problems are solved by a coated asphalt and a preparation method thereof. Summary of the Invention

[0006] The object of the present invention is to provide a coated asphalt and a preparation method thereof to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: ethylene tar and catalytic oil slurry are sequentially mixed, settled and heated to obtain a pretreated product; The pretreated product is subjected to an oxidative cross-linking catalytic reaction and a condensation polymerization catalytic reaction in sequence to obtain a crude asphalt product; The crude asphalt product is extracted to obtain the coated asphalt.

[0008] Preferably, the temperature of the oxidative crosslinking catalytic reaction is 250 to 320 degrees, and the time is 3 to 5 hours; The temperature of the polycondensation catalytic reaction is 320 to 360 degrees and the time is 6 to 10 hours; The catalyst for the oxidative crosslinking catalytic reaction includes vinyltriethoxysilane or dicumyl peroxide; The catalyst for the polycondensation reaction includes random poly-α-olefin, ferric chloride or phosphoric acid. Preferably, the mass ratio of the catalyst for the oxidative crosslinking reaction to the total amount of the ethylene tar and the catalytic oil slurry is 1:30 to 100; The mass ratio of the ethylene tar to the total amount of the catalytic oil slurry is 1:20 to 50.

[0009] Preferably, the oxidative cross-linking catalytic reaction is carried out under the condition of passing a mixed gas of oxygen and nitrogen, the oxygen content of the mixed gas is 5-10%, and the ventilation rate of the mixed gas is 800-1200 sccm; The polycondensation catalytic reaction is carried out under the condition of nitrogen gas being introduced, and the nitrogen gas flow rate is 1500-3000 sccm.

[0010] Preferably, the mass ratio of the ethylene tar to the catalytic oil slurry is 8 to 9:1, the mixing method is physical stirring, the rotation speed of the physical stirring is 150 to 300 rpm, and the time is 8 to 12 hours.

[0011] Preferably, the mass ratio of the sedimentation agent to the total amount of the ethylene tar and the catalytic oil slurry is 1:3-6, and the sedimentation time is 24-48 hours.

[0012] Preferably, the extraction agent includes quinoline or wash oil, the mass ratio of the extraction agent to the crude asphalt product is 1 to 3:1, and the number of extractions is 2 to 4 times.

[0013] Preferably, the softening point of the coated asphalt is 240-265 degrees, the quinoline insoluble matter content is 0.4-1%, the coking value is 75-80%, and the yield is 25-31%.

[0014] Preferably, the negative electrode material includes graphite material.

[0015] The technical effects and advantages of the present invention are as follows: 1. The experimental data of the embodiments of the present invention show that the coated asphalt prepared by the present invention can improve the actual specific capacity and cycle stability of the negative electrode material of the battery after coating the negative electrode material of the lithium-ion battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the process structure of the present invention. DETAILED DESCRIPTION

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0018] The present invention provides Figure 1 A coated asphalt and a preparation method thereof are shown, The present invention provides a method for preparing coated asphalt, comprising the following steps: The ethylene tar and the catalytic oil slurry are sequentially mixed, settled and heated to obtain a pretreated product; The pretreated product is subjected to an oxidative cross-linking catalytic reaction and a condensation polymerization catalytic reaction in sequence to obtain a crude asphalt product; The crude asphalt product is extracted to obtain the coated asphalt.

[0019] Unless otherwise specified, the raw materials used in the present invention are all commercially available.

[0020] The present invention sequentially mixes ethylene tar and catalytic oil slurry, sediments, and heat-treats them to obtain a pretreated product. In the present invention, the mass ratio of the ethylene tar to the catalytic oil slurry is preferably 8 to 9:1, more preferably 8 to 8.5:1, and even more preferably 8:1. In a specific embodiment of the present invention, the ethylene tar is preferably ethylene cracking tar from Daqing Petrochemical Company, and the catalytic oil slurry is preferably catalytic oil slurry from Daqing Petrochemical Company. In the present invention, the mixing method is preferably physical stirring, and the physical stirring is preferably carried out at room temperature. The speed of the physical stirring is preferably 150 to 300 rpm, more preferably 180 to 280 rpm, and even more preferably 200 to 240 rpm. The physical stirring time is preferably 8 to 12 hours, more preferably 9 to 11 hours, and even more preferably 9 to 10 hours. The present invention preferably adopts the above-mentioned raw material ratio and stirring conditions to ensure uniform mixing of the raw materials and enhance the subsequent oxidative crosslinking effect.

[0021] In the present invention, the sedimentation sedimentation agent is preferably Xiangyu AS204 slurry sedimentation agent. In the present invention, the mass ratio of the sedimentation agent to the total amount of ethylene tar and catalytic slurry is preferably 1: 3 to 6, more preferably 1: 4 to 6, and further preferably 1: 4 to 5. The sedimentation time is preferably 24 to 48 hours, more preferably 26 to 40 hours, and further preferably 30 to 36 hours. The present invention preferably adopts the above-mentioned sedimentation conditions so that the impurity particles in the raw materials, especially the catalyst particles in the catalytic tar, can be completely settled, so that the prepared coated asphalt can improve the specific capacity and cycle stability of graphite after coating the graphite. In the present invention, the temperature of the heat treatment is preferably 100 to 150 degrees, more preferably 120 to 145 degrees, further preferably 125 to 140 degrees, and most preferably 130 to 135 degrees. The time of the heat treatment is preferably 0.5 to 1 hour, more preferably 0.6 to 0.9 hours, and further preferably 0.7 to 0.8 hours. The present invention preferably improves the fluidity of the pretreated product by heat treatment, which is beneficial to improving the material transfer speed and production continuity during the production process.

[0022] After obtaining the pretreated product, the present invention sequentially subjects the pretreated product to an oxidative crosslinking catalytic reaction and a condensation polymerization catalytic reaction to obtain a crude asphalt product. In the present invention, the oxidative crosslinking catalytic reaction primarily crosslinks the remaining light components in the asphalt into carbon-containing macromolecules, and the condensation polymerization catalytic reaction primarily dehydrogenates and aromatizes the unsubstituted aromatics in the asphalt. In the present invention, the catalyst for the oxidative crosslinking catalytic reaction is preferably added when the temperature reaches the temperature required for the oxidative crosslinking catalytic reaction, and the catalyst for the condensation polymerization catalytic reaction is preferably added when the temperature reaches the temperature required for the condensation polymerization catalytic reaction. The catalyst addition method is well known to those skilled in the art. In the present invention, the oxidative crosslinking catalytic reaction and the condensation polymerization catalytic reaction are preferably carried out in a high-temperature, high-pressure oxidation reactor. The oxidative crosslinking catalytic reaction and the condensation polymerization catalytic reaction are preferably carried out under stirring, and the stirring speed is preferably 60 to 120 rpm, more preferably 70 to 100 rpm, further preferably 80 to 95 rpm, and most preferably 85 to 92 rpm. In the present invention, the pretreated product is heated to the temperature required for the oxidative crosslinking catalytic reaction, and the heating rate is preferably 4-6 degrees Celsius / min, more preferably 4.5-5.5 degrees Celsius / min, and even more preferably 5 degrees Celsius / min. In the present invention, the pretreated product is heated to the temperature required for the oxidative crosslinking catalytic reaction while nitrogen is introduced, and the nitrogen flow rate is preferably 200-500 seem, more preferably 300-450 seem, and even more preferably 350-400 seem. In the present invention, the catalyst for the oxidative crosslinking catalytic reaction preferably includes vinyltriethoxysilane or dicumyl peroxide, more preferably vinyltriethoxysilane. In the present invention, the mass ratio of the oxidative crosslinking catalytic reaction catalyst to the ethylene tar to the total amount of the catalyst slurry is preferably 1:30-100, more preferably 1:32-75, even more preferably 1:33-65, and most preferably 1:35-50. The temperature of the oxidative crosslinking catalytic reaction is preferably 250 to 320 degrees, more preferably 260 to 310 degrees, further preferably 270 to 300 degrees, and most preferably 275 to 295 degrees. The time of the oxidative crosslinking catalytic reaction is preferably 3 to 5 hours, more preferably 3.5 to 4.8 hours, and further preferably 4 to 4.5 hours. In the present invention, the oxidative crosslinking catalytic reaction is preferably carried out under the condition of passing a mixed gas of oxygen and nitrogen. The oxygen content of the mixed gas is preferably 5 to 10%, more preferably 6 to 9%, and further preferably 7 to 8%. The ventilation rate of the mixed gas is preferably 800 to 1200 sccm, more preferably 850 to 1100 sccm, and further preferably 900 to 1000 sccm.In the present invention, the oxidative cross-linking catalytic reaction can accelerate the degree of oxidative cross-linking reaction of asphalt, promote the cross-linking of the remaining light components in the asphalt into macromolecules, and after the light components are cross-linked into macromolecules, the residual carbon rate can be increased, and the electrochemical performance of the asphalt-coated bitumen can be improved. At the same time, the content of quinoline insolubles in the asphalt can be reduced.

[0023] In the present invention, the catalyst for the polycondensation reaction preferably includes random poly-α-olefins, ferric chloride, or phosphoric acid, more preferably random poly-α-olefins or ferric chloride, and even more preferably random poly-α-olefins. In the present invention, the mass ratio of the polycondensation reaction catalyst to the total amount of ethylene tar and catalytic oil is preferably 1:20-50, more preferably 1:22-45, even more preferably 1:25-40, and most preferably 1:30-35. The temperature of the polycondensation reaction is preferably 320-360 degrees, more preferably 335-357 degrees, even more preferably 340-356 degrees, and most preferably 350-355 degrees. The duration of the polycondensation reaction is preferably 6-10 hours, more preferably 7-9 hours, even more preferably 7.5-8.5 hours, and most preferably 8 hours. In the present invention, the temperature is preferably increased from the temperature of the oxidative crosslinking reaction to the temperature of the polycondensation reaction at a heating rate of 4-6 degrees / min, more preferably 5-6 degrees / min, and most preferably 5 degrees / min. In the present invention, the polycondensation catalytic reaction is preferably carried out under the condition of passing nitrogen, and the nitrogen ventilation rate is preferably 1500-3000sccm, more preferably 1600-2500sccm, and further preferably 1700-1800sccm. In the present invention, the polycondensation catalytic reaction can accelerate the dehydrogenation and aromatization of unsubstituted aromatics in asphalt, thereby greatly improving the softening point of asphalt. In the present invention, after the polycondensation catalytic reaction is completed, the crude asphalt is preferably cooled by natural cooling, and the natural cooling time is preferably 1-2h, more preferably 1.2-1.8h, and further preferably 1.3-1.5h. The present invention preferably reduces the occurrence of side reactions by controlling the above-mentioned cooling conditions, so that the softening point, quinoline insoluble content and coking value of the asphalt do not rise too high, thereby reducing the yield.

[0024] After obtaining the crude asphalt product, the present invention extracts the crude asphalt product to obtain the coated asphalt. In the present invention, the extraction agent preferably includes quinoline or wash oil, more preferably wash oil. In the present invention, the mass ratio of the extractant to the crude asphalt product is preferably 1 to 3:1, more preferably 1.5 to 2.8:1, and further preferably 1.7 to 2.5:1, and the number of extractions is preferably 2 to 4 times, more preferably 3 to 4 times, and further preferably 3 times. The present invention preferably further reduces the quinoline insoluble content in the coated asphalt by the above-mentioned extraction conditions. In the present invention, after the extraction, it is also preferred to dry the coated asphalt, and the drying is preferably carried out in a blast drying oven.

[0025] The present invention also provides a coated asphalt obtained by the preparation method described in the above scheme. The coated asphalt has a softening point of 240-265°C, preferably 245-260°C, and more preferably 250-255°C. The coated asphalt has a quinoline-insoluble matter content of 0.4-1%, preferably 0.42-0.88%, and more preferably 0.44-0.8%. The coking value is 75-80%, preferably 76-78%, and the yield is 25-31%, preferably 26-30%, and more preferably 27-29%. The coated asphalt prepared by the present invention can meet the commercial requirements for coating asphalt for negative electrode materials.

[0026] The present invention also provides the use of the coated asphalt described in the above technical solution in coating a negative electrode material for a lithium-ion battery, wherein the negative electrode material includes a graphite material, and the graphite material preferably includes a natural graphite material or an artificial graphite material. In the present invention, the method of the application preferably includes: mixing the coated asphalt and the negative electrode material to obtain a mixture, and reacting the mixture under heating conditions to obtain a coated negative electrode material. In the present invention, the reaction is preferably carried out under a nitrogen atmosphere, and the mass ratio of the coated asphalt to the negative electrode material is preferably 1:10 to 1:50, more preferably 1:10 to 1:20, and further preferably 1:11 to 1:15. The temperature of the reaction of the coated asphalt and the negative electrode material is preferably 900 to 1200 degrees, more preferably 1000 to 1100 degrees, and the reaction time is preferably 60 to 120 minutes, more preferably 60 to 90 minutes. In the present invention, the reaction can cause the coated asphalt to undergo a high-temperature carbonization reaction, resulting in a certain degree of transformation of amorphous graphite into crystalline graphite, thereby improving the electrochemical performance of the coated negative electrode material.

[0027] The technical solutions of the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Example

[0028] Ethylene tar and catalytic oil slurry were mixed in a mass ratio of 9:1 and mixed at 240 rpm for 10 h at room temperature. Then, AS204 oil slurry settler was added to the mixture of ethylene tar and catalytic oil for chemical sedimentation. The mass ratio of AS204 oil slurry settler to the total amount of ethylene tar and catalytic oil slurry was 1:4. The mixture was settled for 48 h. The settled mixture was heated at 130 degrees for 0.5 h for pretreatment. The pretreated product was placed in a high-temperature and high-pressure reactor for multi-stage heating reaction. Nitrogen, a mixture of nitrogen and oxygen with an oxygen content of 8%, and nitrogen were introduced into the heating, oxidative cross-linking catalytic reaction, and polycondensation catalytic reaction stages, respectively. The ventilation rates were set to 300, 1000, and 2000 sccm, respectively, and the stirring rate was 92 r / min. In the heating stage, The rate of the first stage is 5 degrees / min, the oxidation cross-linking catalytic reaction is carried out at a constant temperature of 280 degrees for 3 hours, the catalyst used is vinyl triethoxysilane, and the mass ratio of vinyl triethoxysilane and ethylene tar to the total amount of catalytic oil slurry is 1:50; the heating rate when the oxidation cross-linking catalytic reaction stage is changed to the condensation polymerization catalytic reaction is 5 degrees / min; the condensation polymerization catalytic reaction is carried out at a constant temperature of 342 degrees for 8 hours, the catalyst used is random poly α-olefin, and the mass ratio of random poly α-olefin and ethylene tar to the total amount of catalytic oil slurry is 1:25, and a crude asphalt product is obtained; after the heating is completed, the crude asphalt product is naturally cooled for 1 hour, and washing oil is added to the crude asphalt for extraction, the mass ratio of washing oil to crude asphalt is 2:1, and extraction is carried out 4 times, and the coated asphalt is obtained after drying. The asphalt softening point was determined according to GB / T4507-2014, the coking value was determined according to GB / T8727-2008, and the quinoline-insoluble matter content was determined according to GB / T2293-2019. The coated asphalt had a softening point of 255°C, a quinoline-insoluble matter content of 0.44%, a coking value of 80%, and a yield of 29.1%. Example

[0029] Ethylene tar and catalytic oil slurry are mixed in a mass ratio of 8:1 and mixed at 150rpm for 11 hours at room temperature. Then, AS204 oil slurry settler is added to the mixture of ethylene tar and catalytic oil for chemical sedimentation. The mass ratio of AS204 oil slurry settler to the total amount of ethylene tar and catalytic oil slurry is 1:5. The mixture is settled for 24 hours. The settled mixture is heated at 135 degrees for 0.8 hours for pretreatment. The pretreated product is placed in a high-temperature and high-pressure reactor for multi-stage heating reaction. Nitrogen, a mixture of nitrogen and oxygen with an oxygen content of 6%, and nitrogen are introduced into the heating, oxidative cross-linking catalytic reaction, and polycondensation catalytic reaction stages, respectively. The ventilation rates are set to 400, 900, and 1800 sccm, respectively, and the stirring rate is 90 r / min. Among them, the rate in the heating stage is 4 degrees / min, and the oxidative cross-linking catalytic reaction is reacted at a constant temperature of 317 degrees for 5 hours. The catalyst used is vinyl triethoxysilane. Vinyl triethoxysilane and ethylene tar and catalytic reaction are mixed at a mass ratio of 1:1. The mass ratio of the total amount of slurry oil was 1:33; the heating rate when switching from the oxidative crosslinking catalytic reaction stage to the polycondensation catalytic reaction was 4 degrees Celsius / min; the polycondensation catalytic reaction was carried out at a constant temperature of 336 degrees Celsius for 8 hours, using random poly-α-olefin as the catalyst, and the mass ratio of random poly-α-olefin and ethylene tar to the total amount of catalytic slurry oil was 1:50, thereby obtaining a crude asphalt product; after heating, the crude asphalt product was naturally cooled for 2 hours, and quinoline was added to the crude asphalt for extraction at a mass ratio of quinoline to crude asphalt of 3:1, extracted twice, and dried to obtain the coated asphalt. The determination method was the same as in Example 1, and the softening point of the coated asphalt was measured to be 247 degrees Celsius, the quinoline insoluble content was 0.79%, the coking value was 75%, and the yield was 25.6%. Example

[0030] Ethylene tar and catalytic oil slurry were mixed in a mass ratio of 8:1 and mixed at 260 rpm for 9 hours at room temperature. Then, AS204 oil slurry settler was added to the mixture of ethylene tar and catalytic oil for chemical sedimentation. The mass ratio of AS204 oil slurry settler to the total amount of ethylene tar and catalytic oil slurry was 1:6. The mixture was settled for 30 hours. The settled mixture was heated at 140 degrees for 0.7 hours for pretreatment. The pretreated product was placed in a high-temperature and high-pressure reactor for multi-stage heating reaction. Nitrogen, a mixture of nitrogen and oxygen with an oxygen content of 8%, and nitrogen were introduced into the temperature rising, oxidative cross-linking catalytic reaction, and polycondensation catalytic reaction stages, respectively. The ventilation rates were set to 350, 800, and 1700 sccm, respectively, and the stirring rate was 85 r / min. In the temperature rising stage, The rate was 5 degrees / min, the oxidation cross-linking catalytic reaction was kept at a constant temperature for 4 hours at 255 degrees, the catalyst used was vinyl triethoxysilane, and the mass ratio of vinyl triethoxysilane and ethylene tar to the total amount of catalytic oil was 1:100; the heating rate when changing from the oxidation cross-linking catalytic reaction stage to the polycondensation catalytic reaction was 5 degrees / min; the polycondensation catalytic reaction was kept at a constant temperature for 8 hours at 357 degrees, the catalyst used was random polyalphaolefin, and the mass ratio of random polyalphaolefin and ethylene tar to the total amount of catalytic oil was 1:20, to obtain a crude asphalt product; after the heating was completed, the crude asphalt product was naturally cooled for 1 hour, and wash oil was added to the crude asphalt for extraction, the mass ratio of wash oil to crude asphalt was 3:1, and extraction was performed 4 times. After drying, the coated asphalt was obtained. The determination method was the same as in Example 1, and the softening point of the coated asphalt was measured to be 263 degrees, the quinoline insoluble content was 0.67%, the coking value was 78%, and the yield was 27.5%.Example 4 Ethylene tar and catalytic slurry were mixed in a mass ratio of 8:1 and mixed at 300 rpm at room temperature for 11.5 hours. Then, AS204 slurry settler was added to the mixture of ethylene tar and catalytic oil for chemical precipitation. The mass ratio of AS204 slurry settler to the total amount of ethylene tar and catalytic slurry was 1:4. The mixture was settled for 25 hours. The settled mixture was heated at 145 degrees for 0.9 hours for pretreatment. The pretreated product was placed in a high-temperature and high-pressure reactor for multi-stage heating reaction. Nitrogen, a mixture of nitrogen and oxygen with an oxygen content of 10%, and nitrogen were introduced into the heating, oxidative cross-linking catalytic reaction, and polycondensation catalytic reaction stages, respectively. The ventilation rates were set to 300, 1000, and 2000 sccm, respectively, and the stirring rate was 80 r / min. Among them, the rate in the heating stage was 6 degrees / min, the oxidative cross-linking catalyst was stirred for 1 hour, and the stirring rate was 80 r / min. The catalytic reaction was carried out at a constant temperature of 294°C for 5 hours, using vinyl triethoxysilane as the catalyst, and a mass ratio of vinyl triethoxysilane to ethylene tar to the total amount of the catalytic oil of 1:35. The heating rate when switching from the oxidative crosslinking catalytic reaction stage to the polycondensation catalytic reaction was 6°C / min. The polycondensation catalytic reaction was carried out at a constant temperature of 357°C for 8 hours, using random poly-α-olefin as the catalyst, and a mass ratio of random poly-α-olefin to ethylene tar to the total amount of the catalytic oil of 1:20, to obtain a crude asphalt product. After the heating was completed, the crude asphalt product was naturally cooled for 1.5 hours, and wash oil was added to the crude asphalt for extraction, with the mass ratio of wash oil to crude asphalt being 1:1. The extraction was repeated twice, and the coated asphalt was dried. The determination method was the same as in Example 1, and the softening point of the coated asphalt was measured to be 251°C, the quinoline insoluble content was 0.95%, the coking value was 76%, and the yield was 25.6%. Example

[0031] Ethylene tar and catalytic slurry were mixed in a mass ratio of 9:1 and mixed at 180 rpm for 8 h at room temperature. Then, AS204 slurry settler was added to the mixture of ethylene tar and catalytic oil for chemical sedimentation. The mass ratio of AS204 slurry settler to the total amount of ethylene tar and catalytic slurry was 1:5. The mixture was settled for 48 h. The settled mixture was heated at 150 degrees for 1.0 h for pretreatment. The pretreated product was placed in a high-temperature and high-pressure reactor for multi-stage heating reaction. Nitrogen, a mixture of nitrogen and oxygen with an oxygen content of 7%, and nitrogen were introduced into the heating, oxidative cross-linking catalytic reaction, and polycondensation catalytic reaction stages, respectively. The ventilation rates were set to 500, 1200, and 1500 sccm, respectively, and the stirring rate was 70 r / min. In the heating stage, The rate of the first stage was 5 degrees / min, the oxidation cross-linking catalytic reaction was kept at a constant temperature for 3 hours at 266 degrees, the catalyst used was vinyl triethoxysilane, and the mass ratio of vinyl triethoxysilane and ethylene tar to the total amount of catalytic oil was 1:50; the heating rate when changing from the oxidation cross-linking catalytic reaction stage to the polycondensation catalytic reaction was 5 degrees / min; the polycondensation catalytic reaction was kept at a constant temperature for 8 hours at 352 degrees, the catalyst used was random poly-α-olefin, and the mass ratio of random poly-α-olefin and ethylene tar to the total amount of catalytic oil was 1:25, to obtain a crude asphalt product; after the heating was completed, the crude asphalt product was naturally cooled for 2 hours, quinoline was added to the crude asphalt for extraction, the mass ratio of quinoline to crude asphalt was 3:1, the extraction was repeated 3 times, and the coated asphalt was dried. The determination method was the same as in Example 1, and the softening point of the coated asphalt was measured to be 253 degrees, the quinoline insoluble content was 0.68%, the coking value was 7.7%, and the yield was 26.9%.

[0032] Table 1 Specific capacity and charge-discharge efficiency of the coated asphalt-coated artificial graphite prepared in Examples 1 to 7 at a current density of 0.5 A·g-1 <![CDATA[Initial charge specific capacity (mAh g -1 )]]> <![CDATA[Initial discharge specific capacity (mAh g -1 )]]> First charge and discharge efficiency% 100-cycle specific capacity% Example 1 398.71 421.76 94.53 98.66 Example 2 377.25 402.13 93.81 98.24 Example 3 281.44 408.26 93.53 97.20 Example 4 375.66 403.95 92.99 96.47 Example 5 374.02 403.59 92.67 94.14 Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing coated asphalt, characterized in that: The following steps are involved: The ethylene tar and the catalytic oil slurry are sequentially mixed, settled and heated to obtain a pretreated product; The pretreated product is subjected to an oxidative cross-linking catalytic reaction and a condensation polymerization catalytic reaction in sequence to obtain a crude asphalt product; The crude asphalt product is extracted to obtain the coated asphalt.

2. The preparation method according to claim 1, characterized in that The temperature of the oxidative crosslinking catalytic reaction is 250 to 320 degrees and the time is 3 to 5 hours; The temperature of the polycondensation catalytic reaction is 320 to 360 degrees and the time is 6 to 10 hours; The catalyst for the oxidative crosslinking catalytic reaction includes vinyltriethoxysilane or dicumyl peroxide; The catalyst for the polycondensation reaction includes random poly-α-olefin, ferric chloride or phosphoric acid.

3. The preparation method according to claim 2, characterized in that The mass ratio of the catalyst for the oxidative crosslinking catalytic reaction to the total amount of the ethylene tar and the catalytic oil slurry is 1:30 to 100; The mass ratio of the ethylene tar to the total amount of the catalytic oil slurry is 1:20 to 50.

4. The preparation method according to claim 2, characterized in that The oxidative cross-linking catalytic reaction is carried out under the condition of passing a mixed gas of oxygen and nitrogen, wherein the oxygen content of the mixed gas is 5-10%, and the ventilation rate of the mixed gas is 800-1200 sccm; The polycondensation catalytic reaction is carried out under the condition of nitrogen gas being introduced, and the nitrogen gas flow rate is 1500-3000 sccm.

5. The preparation method according to claim 1, characterized in that The mass ratio of the ethylene tar to the catalytic oil slurry is 8 to 9:1, the mixing method is physical stirring, the rotation speed of the physical stirring is 150 to 300 rpm, and the time is 8 to 12 hours.

6. The preparation method according to claim 1, characterized in that The mass ratio of the sedimentation agent to the total amount of the ethylene tar and the catalytic oil slurry is 1:3-6, and the sedimentation time is 24-48 hours.

7. The preparation method according to claim 1, characterized in that The extraction agent includes quinoline or washing oil, the mass ratio of the extraction agent to the crude asphalt product is 1 to 3:1, and the number of extractions is 2 to 4 times.

8. The coated asphalt obtained by the preparation method according to any one of claims 1 to 7, characterized in that: The coated asphalt has a softening point of 240-265 degrees, a quinoline insoluble matter content of 0.4-1%, a coking value of 75-80%, and a yield of 25-31%.

9. The use of the coated asphalt according to claim 8 in coating anode materials of lithium-ion batteries, characterized in that: The negative electrode material includes graphite material.

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