A method for producing needle coke for a negative electrode material or an ultrahigh power electrode

Abstract

The application discloses a preparation method of needle coke for negative materials or super high power electrodes. Different purifying pitch is obtained by using different purification technologies, and then combined with petroleum pitch, the pitch with uniform components and moderate reaction is obtained by using the component segmentation and combination method. Then in the process of mesophase thermal conversion, the viscosity of the reaction system is controlled, so that the needle coke for high-quality super high power electrodes and the needle coke for high-quality lithium ion battery negative materials are obtained.

Description

Technical Field

[0001] This invention belongs to the field of deep processing of coal tar pitch, and particularly relates to a method for preparing needle coke for negative electrode materials or ultra-high power electrodes, such as needle coke raw materials used in the preparation of ultra-high power electrodes and lithium-ion negative electrode materials. Background Technology

[0002] Coal tar pitch is a major product of coal tar deep processing, accounting for more than 50% of the total coal tar output. China is a major producer and user of coal tar pitch, with a current production exceeding 2 million tons. Therefore, the deep processing and application of coal tar pitch has profound significance for the development of coal chemical industry. Pitch pitch is a mixture of many components, all of which are complex compounds with large molecular weights, primarily composed of carbon and hydrogen atoms. Furthermore, its components are difficult to separate, and therefore, most of its components are unknown.

[0003] The compositional distribution of asphalt is of great guiding significance for exploring the use of asphalt in the manufacture of carbon materials such as needle coke and carbon microspheres. In the past 30 years, with the development of various instrumental analysis methods, the research on the chemical composition of asphalt has been greatly promoted.

[0004] Needle coke prepared from asphalt is the main raw material for preparing electrodes and battery anode materials. However, at present, anode materials and ultra-high power electrodes still use only purified asphalt to manufacture needle coke. Therefore, the quality of the needle coke prepared can only be maintained within a certain range, which affects the prepared anode materials and ultra-high power electrodes. In recent years, with the continuous research on asphalt components, the needle coke manufacturing technology for ultra-high power electrodes and anode materials has also been developing. The structure and properties of the needle coke raw material used are still the key to this technology.

[0005] In view of the above, there is an urgent need to develop a method for preparing needle coke for negative electrode materials or ultra-high power electrodes, which can improve the quality of needle coke and thus produce high-quality ultra-high power electrodes. Summary of the Invention

[0006] To address the aforementioned deficiencies in existing technologies, the present invention aims to provide a method for preparing needle coke for anode materials or ultra-high power electrodes. This method involves employing different purification techniques to obtain different purified asphalts, and combining them with petroleum-based asphalt. By using a component segmentation and combination method, a uniformly composed asphalt with a suitable reactivity is obtained. Then, during the mesophase thermal conversion process, the viscosity of the reaction system is controlled to obtain high-quality needle coke for ultra-high power electrodes and high-quality needle coke for lithium-ion battery anode materials.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] The first aspect of this invention provides a method for preparing needle coke for negative electrode materials, comprising the following steps:

[0009] S11, the first purified asphalt is obtained by flash evaporation, and the second purified asphalt is obtained by solvent sedimentation and solvent centrifugation.

[0010] S12, after the first purified asphalt and the second purified asphalt are proportioned, they are then mixed evenly with the remaining tailings asphalt of the mesophase carbon microspheres to obtain mixed asphalt;

[0011] S13, needle coke for negative electrode materials is obtained by thermal conversion of mixed asphalt through mesophase.

[0012] Preferably, in step S11, the softening point of the first purified asphalt is 35-55°C.

[0013] Preferably, in step S12, the ratio of the first purified asphalt, the second purified asphalt, and the remaining tailings asphalt of the mesophase carbon microspheres is 20-30%: 70-60%: 8-12%.

[0014] Preferably, in step S13, during the mesophase thermal conversion process, the conversion temperature is 400–460°C, the conversion time is 18–36 h, and the conversion pressure is 0–5 kg / cm². 2 .

[0015] Preferably, in step S13, the coefficient of thermal expansion of the needle coke used as the negative electrode material is 1.2 × 10⁻⁶. -6 ~1.4×10 -6 / ℃ (room temperature to 600℃), resistivity is 50 to 550 μΩm.

[0016] A second aspect of the present invention provides a method for preparing needle coke for ultra-high power electrodes, comprising the following steps:

[0017] S21, the first purified asphalt is obtained by flash evaporation, and the second purified asphalt is obtained by solvent sedimentation and solvent centrifugation.

[0018] S22, after the first purified asphalt and the second purified asphalt are proportioned, they are then mixed evenly with petroleum-based asphalt to obtain mixed asphalt;

[0019] S23, needle coke for negative electrode materials is obtained by thermal conversion of mixed asphalt through mesophase.

[0020] Preferably, in step S21, the softening point of the first purified asphalt is 35-55°C.

[0021] Preferably, in step S22:

[0022] The ratio of the first purified asphalt, the second purified asphalt, and petroleum-based asphalt is 20-30%: 70-60%: 8-12%; and / or

[0023] The petroleum-based bitumen is ethylene tar or catalytic cracking clarified slurry oil.

[0024] Preferably, in step S23, during the mesophase thermal conversion process, the conversion temperature is 400–460°C, the conversion time is 18–36 h, and the conversion pressure is 0–5 kg / cm². 2 .

[0025] Preferably, in step S13, the coefficient of thermal expansion of the needle coke used for the ultra-high power electrode is 0.9 to 1.2 × 10⁻⁶. -6 / ℃ (room temperature to 600℃), resistivity is 450 to 550 μΩm.

[0026] The method for preparing needle coke for negative electrode materials or ultra-high power electrodes provided by this invention has the following beneficial effects:

[0027] The method for preparing needle coke for anode materials or ultra-high power electrodes of the present invention involves obtaining different purified asphalts by employing different purification technologies, and combining them with petroleum-based asphalts by using a component segmentation and combination method to obtain asphalts with uniform composition and moderate reactivity. Then, during the mesophase thermal conversion process, the viscosity of the reaction system is controlled by controlling the conversion temperature, conversion pressure and conversion time, thereby obtaining high-quality needle coke for ultra-high power electrodes and high-quality needle coke for lithium-ion battery anode materials. Attached Figure Description

[0028] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0029] Figure 1 A schematic flowchart of the preparation method of needle coke for negative electrode materials;

[0030] Figure 2 A schematic flowchart of the preparation method of needle coke for ultra-high power electrodes. Detailed Implementation

[0031] To better understand the above-mentioned technical solutions of the present invention, the technical solutions of the present invention will be further described below in conjunction with embodiments.

[0032] Combination Figure 1 , Figure 2As shown, the present invention provides a method for preparing needle coke for negative electrode materials or ultra-high power electrodes. Different purification techniques are used to obtain different purified asphalts. At the same time, petroleum-based asphalt is combined with component segmentation and combination methods to obtain asphalt with uniform composition and moderate reactivity. Then, during the mesophase thermal conversion process, the viscosity of the reaction system is controlled to obtain high-quality needle coke for ultra-high power electrodes and high-quality needle coke for lithium-ion battery negative electrode materials.

[0033] Among them, the combination Figure 1 As shown, the preparation method of needle coke for negative electrode materials includes the following steps:

[0034] S11, the first purified asphalt with a softening point of 35-55℃ is obtained by flash evaporation, and the second purified asphalt is obtained by solvent sedimentation and solvent centrifugation.

[0035] S12, after the first purified asphalt and the second purified asphalt are proportioned, they are then mixed evenly with the remaining tailings asphalt of the mesophase carbon microspheres to obtain mixed asphalt; wherein the mass percentage of the first purified asphalt, the second purified asphalt and the remaining tailings asphalt of the mesophase carbon microspheres is 20-30%: 70-60%: 8-12%. In a further embodiment, the remaining tailings of the mesophase carbon microspheres in the mixed asphalt can be proportioned at about 10%.

[0036] S13, needle coke for negative electrode materials is obtained by mesophase thermal conversion of mixed asphalt; wherein, during the mesophase thermal conversion process, the conversion temperature is controlled at 400-460℃, the conversion time at 18-36h, and the conversion pressure at 0-5kg / cm². 2 The final high-quality needle coke for lithium-ion battery anode materials exhibits the following properties: a coefficient of thermal expansion of 1.2–1.4 × 10⁻⁶. -6 / ℃ (room temperature to 600℃), resistivity is 500 to 550 μΩm.

[0037] Using the above-mentioned lithium-ion battery anode material, a needle coke is used to make a lithium-ion battery anode, with an initial charge / discharge capacity >350mAh / g and a coulombic efficiency >95%.

[0038] Combination Figure 2 As shown, the method for preparing needle coke for ultra-high power electrodes includes the following steps:

[0039] S21, the first purified asphalt with a softening point of 35-55℃ is obtained by flash evaporation, and the second purified asphalt is obtained by solvent sedimentation and solvent centrifugation.

[0040] S22, after the first purified asphalt and the second purified asphalt are proportioned, they are then mixed evenly with the remaining tailings asphalt of the mesophase carbon microspheres to obtain mixed asphalt; wherein the mass percentages of the first purified asphalt, the second purified asphalt and the petroleum-based asphalt are 20-30%: 70-60%: 8-12%; the petroleum-based asphalt is selected from ethylene tar or catalytic cracking clarified slurry oil, etc.; in a further embodiment, the petroleum-based asphalt in the mixed asphalt can be proportioned at about 10%.

[0041] S23, needle coke for ultra-high power electrodes is obtained by thermal conversion of mixed asphalt through mesophase; wherein, during the mesophase thermal conversion process, the conversion temperature is controlled at 400–460℃, the conversion time at 18–36 h, and the conversion pressure at 0–5 kg / cm². 2 The final performance of the needle coke used for ultra-high power electrodes is as follows: thermal expansion coefficient is 0.9–1.2 × 10⁻⁶. -6 / ℃ (room temperature to 600℃), resistivity is 450 to 550 μΩm.

[0042] Using the aforementioned ultra-high power electrode needle coke to fabricate the negative electrode of a lithium-ion battery, the initial charge-discharge capacity is >350mAh / g and the coulombic efficiency is >95%.

[0043] The preparation method of needle coke for negative electrode material or ultra-high power electrode of the present invention will be further described below with specific examples.

[0044] Example 1

[0045] In this embodiment, the needle coke used to prepare the negative electrode material is prepared through the following specific process:

[0046] The first purified asphalt, with a softening point of 46℃, was obtained by flash evaporation. The second purified asphalt was then obtained by solvent sedimentation and solvent centrifugation. The first and second purified asphalts were blended at a specific mass percentage ratio: first purified asphalt: second purified asphalt = 25%:65%, with 10% of the remaining tailings of mesophase carbon microspheres added. After thorough mixing, a mixed asphalt was obtained and then converted at 450℃ for 24 hours under a pressure of 2.5 kg / cm². 2 Under certain conditions, mesophase thermal conversion was carried out to obtain high-quality needle coke for lithium-ion battery anode materials. The performance of this needle coke for lithium-ion battery anode materials is as follows: the coefficient of thermal expansion is 1.3 × 10⁻⁶. -6 The resistivity is 530 μΩm. Using the above-mentioned lithium-ion battery anode material, a needle coke was used to fabricate a lithium-ion battery anode, achieving an initial charge / discharge capacity of 353 mAh / g and a coulombic efficiency of 96%.

[0047] Example 2

[0048] In this embodiment, the needle coke for preparing ultra-high power electrodes is prepared through the following specific process:

[0049] First purified asphalt with a softening point of 37℃ was obtained by flash evaporation. Second purified asphalt was then obtained by solvent sedimentation and solvent centrifugation. The first and second purified asphalts were blended at a specific mass percentage ratio: first purified asphalt: second purified asphalt = 28%:64%, with 8% ethylene tar added. After thorough mixing, a mixed asphalt was obtained and then converted at a conversion temperature of 440℃ for 36 hours and a conversion pressure of 5 kg / cm². 2 Under certain conditions, mesophase thermal conversion is carried out to obtain high-quality needle coke for ultra-high power electrodes. The properties of this needle coke are: a thermal expansion coefficient of 1.0 × 10⁻⁶. -6 / ℃ (room temperature to 600℃), resistivity is 500μΩm.

[0050] Example 3

[0051] In this embodiment, the needle coke used to prepare the negative electrode material is prepared through the following specific process:

[0052] The first purified asphalt, with a softening point of 35℃, was obtained by flash evaporation. The second purified asphalt was then obtained by solvent sedimentation and solvent centrifugation. The first and second purified asphalts were blended at a specific mass percentage ratio: first purified asphalt: second purified asphalt = 20%:70%, with 10% of the remaining tailings of mesophase carbon microspheres added. After thorough mixing, a mixed asphalt was obtained and then converted at 400℃ for 36 hours under a pressure of 2.0 kg / cm². 2 Under certain conditions, mesophase thermal conversion was carried out to obtain high-quality needle coke for lithium-ion battery anode materials. The performance of this needle coke for lithium-ion battery anode materials is as follows: the coefficient of thermal expansion is 1.2 × 10⁻⁶. -6 The resistivity is 510 μΩm, with a temperature range of / ℃ (room temperature to 600℃). The above-mentioned lithium-ion battery anode material is a needle-coke lithium-ion battery anode material, with an initial charge / discharge capacity of 355 mAh / g and a coulombic efficiency of 95.4%.

[0053] Example 4

[0054] In this embodiment, the needle coke used to prepare the negative electrode material is prepared through the following specific process:

[0055] The first purified asphalt, with a softening point of 55℃, was obtained by flash evaporation. The second purified asphalt was then obtained by solvent sedimentation and solvent centrifugation. The first and second purified asphalts were mixed in a specific mass percentage ratio: first purified asphalt: second purified asphalt = 30%:60%, with 10% of the remaining tailings of mesophase carbon microspheres added. After thorough mixing, the resulting mixed asphalt was subjected to a conversion at 460℃ for 18 hours and a conversion pressure of 5 kg / cm². 2 Under certain conditions, mesophase thermal conversion was carried out to obtain high-quality needle coke for lithium-ion battery anode materials. The performance of this needle coke for lithium-ion battery anode materials is as follows: the coefficient of thermal expansion is 1.2 × 10⁻⁶. -6 Temperature range: ℃ (room temperature to 600℃), resistivity: 525 μΩm. Initial charge / discharge capacity: 356 mAh / g, coulombic efficiency: 95.3%.

[0056] Example 5

[0057] In this embodiment, the needle coke for preparing ultra-high power electrodes is prepared through the following specific process:

[0058] First purified asphalt with a softening point of 50℃ was obtained by flash evaporation. Second purified asphalt was then obtained by solvent sedimentation and solvent centrifugation. The first and second purified asphalts were blended at a specific mass percentage ratio: first purified asphalt: second purified asphalt = 21%:66%, with 12% ethylene tar added. After thorough mixing, a mixed asphalt was obtained and then converted at 450℃ for 30 hours under a pressure of 5 kg / cm². 2 Under certain conditions, mesophase thermal conversion was carried out to obtain high-quality needle coke for ultra-high power electrodes. The properties of this needle coke for ultra-high power electrodes are as follows: thermal expansion coefficient is 1.1 × 10⁻⁶. -6 / ℃ (room temperature to 600℃), resistivity is 510μΩm.

[0059] Those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. Any variations or modifications to the above embodiments that are within the spirit and essence of the present invention will fall within the scope of the claims of the present invention.

Claims

1. A method for preparing needle coke for negative electrode materials, characterized in that, Includes the following steps: S11, the first purified asphalt with a softening point of 35-55℃ was obtained by flash evaporation. The second purified asphalt was obtained by solvent sedimentation or solvent centrifugation. S12, after proportioning the first and second purified asphalt, is mixed evenly with the remaining tailings of the mesophase carbon microspheres to obtain mixed asphalt. The mass percentages of the first purified asphalt, the second purified asphalt, and the remaining tailings asphalt from the mesophase carbon microspheres are 20-30% : 60-70% : 8-12%; S13, needle coke for lithium-ion battery anode materials is obtained by thermal conversion of mixed asphalt through mesophase. During the mesophase thermal conversion process, the conversion temperature is 400–460℃, the conversion time is 18–36 h, and the conversion pressure is 0–5 kg / cm². 2 , The properties of the needle coke used as the negative electrode material for lithium-ion batteries are as follows: the coefficient of thermal expansion from room temperature to 600℃ is (1.2~1.4)×10⁻⁶. -6 / ℃, resistivity 500~550μΩm. Using the aforementioned anode material to fabricate a lithium-ion battery anode with needle coke, the initial charge / discharge capacity is >350mAh / g, and the coulombic efficiency is >95%.

2. A method for preparing needle coke for ultra-high power electrodes, characterized in that, Includes the following steps: S21, the first purified asphalt with a softening point of 35-55℃ is obtained by flash evaporation. The second purified asphalt was obtained by solvent sedimentation or solvent centrifugation. S22, after the first and second purified asphalts are proportioned, is then mixed evenly with petroleum-based asphalt to obtain mixed asphalt. The mass percentages of the first purified asphalt, the second purified asphalt, and the petroleum-based asphalt are 20-30% : 60-70% : 8-12%; The petroleum-based bitumen is ethylene tar or catalytic cracking clarified slurry oil; S23, needle coke for ultra-high power electrodes is obtained by thermal conversion of mixed asphalt through mesophase. During the mesophase thermal conversion process, the conversion temperature is 400–460℃, the conversion time is 18–36 h, and the conversion pressure is 0–5 kg / cm². 2 , The coefficient of thermal expansion of the needle coke used in the ultra-high power electrode from room temperature to 600°C is (0.9~1.2)×10⁻¹⁰. -6 / ℃, resistivity 450~550μΩm. The ultra-high power electrode is used to make the negative electrode of a lithium-ion battery with needle coke, and the initial charge and discharge capacity is >350mAh / g and the coulombic efficiency is >95%.

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