Preparation method of acetylene carbon black mesocarbon microbead negative electrode material
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NINGXIA CHUANGU CARBON BLACK CO LTD
- Filing Date
- 2024-12-10
- Publication Date
- 2026-06-19
Smart Images
Figure CN120903466B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of anode material technology, specifically to a method for preparing acetylene black mesophase carbon microsphere anode material. Background Technology
[0002] Mesophase carbon microspheres are a novel functional material with good chemical stability, high packing density and easy graphitization, good thermal stability, and excellent electrical and thermal conductivity. They are a high-quality precursor for the preparation of high-performance carbon materials and have broad application and development prospects.
[0003] CN102862973A discloses a method for preparing lithium-ion battery anode materials using mesophase carbon microspheres. The method involves mixing asphalt or aromatic heavy oil with oxides of iron, nickel, or cobalt catalysts to obtain a mixed raw material; heating the mixed raw material to 350-450℃ and holding it at that temperature for 11-15 hours, then naturally cooling it to room temperature in a furnace to obtain a mixture of mesophase carbon microspheres and a matrix; separating the mesophase carbon microspheres from the mixture containing the mesophase carbon microspheres and the matrix at a rotation speed of 21000-15000 r / min; and finally obtaining the mesophase carbon microspheres by spray drying.
[0004] CN115321512A discloses an isotropic carbon microspheres prepared from coal tar pitch and a method thereof. The method obtains isotropic pitch-based carbon microspheres with smooth surfaces by thermally polymerizing and melting heavy components of coal tar pitch into spheres in a dispersion medium.
[0005] CN115340083A discloses a method for preparing small-particle-size pitch-based carbon microspheres, comprising: weighing coal tar pitch and petroleum pitch and mixing them in a mass ratio of (90-10):(10-90) to obtain a mixture; stirring and mixing the mixture in an inert gas-protected reactor for 0.5-2 hours to obtain a blended pitch product; separating the blended pitch by extraction with a detergent to obtain a precursor for small-particle-size pitch-based carbon microspheres; pre-oxidizing the precursor at a certain temperature and then carbonizing it under an inert gas-protected environment to obtain small-particle-size pitch-based carbon microspheres with an average particle size of 0.5-3µm.
[0006] The aforementioned existing technologies typically use asphalt or heavy petroleum as raw materials to prepare mesophase carbon microspheres. The preparation process requires solvent extraction, making it complex. Furthermore, the yield of mesophase carbon microspheres is low. In addition, asphalt or heavy petroleum contains numerous impurities, including sulfides, heavy metals and their compounds, and fine particulate matter. These impurities cannot be completely separated during the separation of mesophase carbon microspheres and instead enter the final product along with the microspheres during the carbonization process, severely impacting the performance indicators of the anode product. Summary of the Invention
[0007] The technical problem to be solved by the present invention is that the existing technology for preparing mesophase carbon microspheres is complex, has low yield, and contains many impurities, which seriously affects the performance indicators of the anode product.
[0008] To address the aforementioned problems, this invention provides a method for preparing acetylene carbon black mesophase carbon microsphere anode material. The method involves simultaneously introducing a mesophase carbon microsphere precursor and acetylene gas into a pyrolysis furnace. The pyrolysis reaction of the acetylene gas and the carbonization reaction of the mesophase carbon microsphere precursor occur simultaneously. The mesophase carbon microsphere precursor is prepared using benzene.
[0009] The present invention employs benzene to directly prepare mesophase carbon microsphere precursors. Benzene, as a starting material, is purer and has a more defined chemical structure compared to asphalt or heavy petroleum. This makes the reaction conditions during the entire synthesis process easier to control, allowing for better design and regulation of the product's porosity, specific surface area, and other microstructures. Consequently, the resulting carbon microspheres exhibit better performance, such as higher electrical conductivity and stronger mechanical strength. Using benzene as a raw material typically reduces the generation of harmful byproducts because benzene itself is a relatively clean chemical raw material; while asphalt or heavy petroleum contain more impurities and are more likely to generate pollutants during processing. Compared to the complex asphalt or heavy oil systems, the process route using benzene as a raw material often involves fewer steps and simpler operating conditions.
[0010] Furthermore, the method for preparing mesophase carbon microsphere precursors using benzene according to the present invention is as follows:
[0011] (1) Dehydrogenation cyclization reaction: Benzene vapor is introduced into a fluidized bed reactor with platinum (Pt) and palladium (Pd) as catalyst system. The temperature inside the reactor is controlled at 500~600°C and the pressure is controlled at 0.5~1.5 MPa. The reaction product is condensed to obtain a liquid phase substance.
[0012] (2) Condensation to form mesophase carbon microsphere precursor: The liquid phase material formed in step (1) is condensed and then introduced into the reactor. The reaction temperature is 400~500°C and the reaction pressure is 5~10 MPa. The reaction yields mesophase carbon microsphere precursor.
[0013] Furthermore, in step (1), the fluidized bed reactor has two layers. The catalysts laid in the first layer of the fluidized bed are platinum (Pt) and palladium (Pd) catalysts, and the catalysts laid in the second layer of the fluidized bed are platinum (Pt), palladium (Pd), and zeolite. The mass ratio of platinum, palladium, and zeolite is (1~0.5):(1~0.5):(1~2), and the reaction yields the mesophase carbon microsphere precursor.
[0014] In this process, benzene vapor first contacts a first fluidized bed catalyst composed of platinum (Pt) and palladium (Pd). Platinum (Pt) and palladium (Pd) effectively promote the breaking of the CH chemical bond in benzene, opening the benzene ring. The dehydrogenated polycyclic aromatic hydrocarbons or large aromatic molecules then contact a second fluidized bed catalyst composed of platinum (Pt), palladium (Pd), and zeolite. Especially under the catalytic action of zeolite, which contains abundant acidic sites (such as Brønsted or Lewis acid sites), these sites effectively activate reactant molecules and promote the formation of C-C bonds. The high specific surface area and ordered pore structure of zeolite are beneficial for improving the diffusion efficiency of reactants and products, thereby accelerating the entire reaction process. Zeolite catalysts typically exhibit good thermal and chemical stability and can be used at high temperatures for extended periods without deactivation.
[0015] Furthermore, in step (2), zirconium oxide sulfate powder catalyst is added.
[0016] The sulfate groups on the surface of zirconium sulfate provide strong Brønsted acid sites, which helps promote polycondensation reactions. As a solid acid catalyst, zirconium sulfate can reduce the need for corrosive liquid acids. The solid catalyst is easy to separate from the reaction mixture and can be regenerated and reused through simple processing methods such as washing and drying.
[0017] Furthermore, 1-butyl-3-methylimidazolium chloride is added as a solvent in step (2).
[0018] 1-Butyl-3-methylimidazolium chloride, as an ionic solvent, has high high-temperature stability and exhibits good chemical inertness to many chemical substances. It is not prone to unnecessary side reactions with reactants. Under conditions of 300~500°C, this solvent can ensure very good solubility for polycyclic aromatic hydrocarbons or macromolecular aromatic compounds formed by benzene dehydrogenation cyclization, and has good mass transfer effect, which promotes condensation reaction and reduces the risk of vaporization of polycyclic aromatic hydrocarbons or macromolecular aromatic compounds.
[0019] Preferably, the reactor in step (2) is a tubular reactor with a spiral stirring device inside.
[0020] Furthermore, after the reaction in step (2) is completed, the mesophase carbon microsphere precursor is separated by high-speed centrifugation filtration or by a filtration membrane.
[0021] Furthermore, the sulfated zirconium oxide powder is first filtered, and then the mesophase carbon microsphere precursor is separated by high-speed centrifugal filtration or filtration membrane.
[0022] The technical advantages of this application are as follows:
[0023] 1. This invention uses benzene to directly prepare mesophase carbon microsphere precursors. Compared to asphalt or heavy petroleum, benzene is a purer starting material with a more defined chemical structure. This makes the reaction conditions during the entire synthesis process easier to control, allowing for better design and regulation of the product's porosity, specific surface area, and other microstructures. Consequently, the resulting carbon microspheres exhibit better performance, such as higher electrical conductivity and stronger mechanical strength. Using benzene as a raw material typically reduces the generation of harmful byproducts because benzene itself is a relatively clean chemical raw material; while asphalt or heavy petroleum contains more impurities and is more likely to generate pollutants during processing. Compared to the complex asphalt or heavy oil systems, the process route using benzene as a raw material often involves fewer steps and simpler operating conditions.
[0024] 2. In this invention, benzene vapor first contacts a first-layer fluidized bed catalyst consisting of platinum (Pt) and palladium (Pd). Platinum (Pt) and palladium (Pd) effectively promote the breaking of the CH chemical bond in benzene, opening the benzene ring. The dehydrogenated polycyclic aromatic hydrocarbons or large aromatic molecules then contact a second-layer fluidized bed catalyst consisting of platinum (Pt), palladium (Pd), and zeolite. Especially under the catalytic action of zeolite, which contains abundant acidic sites (such as Brønsted or Lewis acid sites), these sites effectively activate reactant molecules and promote the formation of C-C bonds. The high specific surface area and ordered pore structure of zeolite are beneficial for improving the diffusion efficiency of reactants and products, thereby accelerating the entire reaction process. Zeolite catalysts typically exhibit good thermal and chemical stability and can be used at high temperatures for extended periods without deactivation.
[0025] 3. In this invention, the sulfate ions on the surface of zirconium sulfate provide strong Brønsted acid sites, which helps to promote the polycondensation reaction. As a solid acid catalyst, zirconium sulfate can reduce the need for corrosive liquid acid. The solid catalyst is easy to separate from the reaction mixture and can be regenerated and reused by simple processing methods such as washing and drying.
[0026] 4. In the precursor for the mesophase carbon microspheres formed by condensation polymerization of the present invention, 1-butyl-3-methylimidazolium chloride is used as an ionic solvent. It has high high-temperature stability, exhibits good chemical inertness to many chemical substances, and is not prone to unnecessary side reactions with reactants. Under conditions of 300~500°C, this solvent can ensure very good solubility for polycyclic aromatic hydrocarbons or macromolecular aromatic compounds formed by benzene dehydrogenation cyclization, and has good mass transfer effect, which promotes the condensation polymerization reaction and reduces the risk of vaporization of polycyclic aromatic hydrocarbons or macromolecular aromatic compounds. Attached Figure Description
[0027] Figure 1 This is a schematic diagram of the fluidized bed reactor of the present invention.
[0028] Figure 2 This is a 1μm SEM image of the acetylene black mesophase carbon microsphere anode material obtained in Example 1 of this invention.
[0029] Figure 3 This is a 500nm SEM image of the acetylene black mesophase carbon microsphere anode material obtained in Example 1 of this invention.
[0030] Explanation of reference numerals in the attached diagram: 1. First fluidized bed; 2. Second fluidized bed. Detailed Implementation
[0031] The embodiments of the technical solution of this application will be described in detail below. The following embodiments are only used to illustrate the technical solution of this application more clearly, and are therefore only examples, and should not be used to limit the scope of protection of this application.
[0032] The present invention provides a method for preparing an acetylene carbon black mesophase carbon microsphere anode material, comprising the following steps:
[0033] Mesophase carbon microsphere precursors were prepared using benzene:
[0034] (1) Dehydrogenation cyclization reaction: Benzene vapor is introduced into a fluidized bed reactor with platinum (Pt) and palladium (Pd) as catalyst system. The temperature inside the reactor is controlled at 500~600°C and the pressure is controlled at 0.5~1.5Mpa. The reaction product is cooled to below 120°C to obtain a liquid phase substance.
[0035] Preferably, in step (1), the fluidized bed reactor has two layers of fluidized bed. The first layer of fluidized bed 1 is lined with a platinum (Pt) and palladium (Pd) catalyst, and the second layer of fluidized bed 2 is lined with a platinum (Pt) and palladium (Pd) catalyst and zeolite. The mass ratio of platinum, palladium and zeolite is (1~0.5):(1~0.5):(1~2).
[0036] (2) Condensation polymerization to form mesophase carbon microsphere precursor: The liquid phase material formed in step (1) is condensed and then introduced into a reactor, and zirconia sulfate powder catalyst is added, along with 1-butyl-3-methylimidazolium chloride as a solvent. The reaction temperature is 400~500°C, and the reaction pressure is 5~10 MPa. The reaction yields the mesophase carbon microsphere precursor. The reactor in step (2) is a tubular reactor with a spiral stirring device inside. After the reaction in step (2) is completed, the zirconia sulfate powder is first filtered, and the mesophase carbon microsphere precursor is separated by high-speed centrifugal filtration or a membrane filtration method.
[0037] The aforementioned mesophase carbon microsphere precursor and acetylene gas are simultaneously introduced into a pyrolysis furnace. The pyrolysis reaction of the acetylene gas and the carbonization reaction of the mesophase microsphere precursor occur simultaneously. The flow rate ratio of the mesophase carbon microsphere precursor to the acetylene gas is:
[0038] The above-mentioned fluidized bed reactor, such as Figure 1 As shown. The reactor in step (2) is a tubular reactor, which is not shown in the figure.
[0039] Example 1
[0040] A method for preparing an acetylene black mesophase carbon microsphere anode material includes the following steps:
[0041] Mesophase carbon microsphere precursors were prepared using benzene:
[0042] (1) Dehydrogenation cyclization reaction: Benzene vapor is continuously fed into a fluidized bed reactor. The fluidized bed reactor has two layers. The first layer of the fluidized bed is a catalyst of platinum (Pt) and palladium (Pd) mixed in a mass ratio of 1:1. The second layer of the fluidized bed is a catalyst of platinum (Pt), palladium (Pd) and zeolite mixed in a mass ratio of 1:1:1. The temperature inside the reactor is controlled at 500℃ and the pressure is controlled at 0.5 MPa. When the reaction product is transported to the condensation system and cooled to below 120℃, a liquid phase substance is obtained.
[0043] (2) Condensation to form mesophase carbon microsphere precursor: The liquid phase material formed in step (1) is introduced into the reactor, and sufficient zirconium sulfate powder catalyst is added. 1-Butyl-3-methylimidazolium chloride is added as solvent. The reaction temperature is 400℃ and the reaction pressure is 5 MPa. After the reaction is completed, the mesophase carbon microsphere precursor is obtained. The mass ratio of the liquid phase material to 1-Butyl-3-methylimidazolium chloride in the benzene step is 1:1.
[0044] The aforementioned mesophase carbon microsphere precursor and acetylene gas are simultaneously introduced into a pyrolysis furnace. The pyrolysis reaction of the acetylene gas and the carbonization reaction of the mesophase microsphere precursor are carried out simultaneously. The mass flow ratio of the mesophase carbon microsphere precursor to the acetylene gas is 2:1.
[0045] Example 2: The difference from Example 1 is that the reaction control conditions of some steps are different, as detailed in Table 1.
[0046] Comparative Example 1: The difference from Example 1 is that no zeolite catalyst is added to the dehydrogenation cyclization reaction, as detailed in Table 1.
[0047] Comparative Example 2: The difference from Example 1 is that no zirconium oxide sulfate powder catalyst was added, as detailed in Table 1.
[0048] Comparative Example 3: The solvent without 1-butyl-3-methylimidazolium chloride, as detailed in Table 1, is the same as that used in Example 1.
[0049] Table 1 Control conditions for each step in each embodiment and comparative example
[0050]
[0051] The products obtained in Example 1 and Example 2 were subjected to performance analysis, and the results are shown in Table 2.
[0052] Table 2. Performance of products obtained from each embodiment and comparative example.
[0053] Example 1 Example 2 <![CDATA[Specific surface area m 2 / g]]> 1328 1327 <![CDATA[Initial discharge specific capacity at a current density of 0.1C / mAh·g -1 > 374 376 <![CDATA[Reversible capacity at the 200th cycle at a current density of 0.1C / mAh·g -1 > 316 317
[0054] As can be seen from Table 1, in Example 1 and Comparative Example 1, the addition of a second fluidized bed in the dehydrogenation cyclization step of Example 1, along with the addition of zeolite as a catalyst, promotes the cyclization reaction. When the temperature in Example 1 was reduced by 150°C, more liquid phase material was obtained than in Comparative Example 1, indicating that the addition of zeolite facilitates the formation of large aromatic molecules.
[0055] As can be seen from Table 1, Examples 1 and Comparative Example 2, in the step of polycondensation to form the mesophase carbon microsphere precursor, Example 1 added zirconium sulfate powder catalyst, and the final separated mesophase carbon microsphere precursor was more abundant.
[0056] As can be seen from Table 1, in Example 1 and Comparative Example 2, when 1-butyl-3-methylimidazolium chloride was added as a solvent during the polycondensation reaction in Example 1, a larger amount of mesophase carbon microsphere precursor was formed after separation. This is because a relatively high temperature is required for the polycondensation reaction to proceed. However, when the temperature is too high, the aromatic compounds resulting from benzene dehydrogenation and cyclization may be vaporized. After vaporization, the intermolecular collision and contact forces are weaker, making it difficult for the polycondensation reaction to proceed.
[0057] From Table 2, Figure 2 , Figure 3 As can be seen, the mesophase carbon microspheres obtained by this invention have superior performance. This indicates that the mesophase carbon microsphere precursor prepared directly from benzene in this invention is purer, has higher electrical conductivity, and a more defined chemical structure compared to asphalt or heavy petroleum.
[0058] Figure 2 , Figure 3 The image shows a SEM image of the mesophase carbon microspheres obtained in Example 1.
[0059] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A method for preparing an acetylene black mesophase carbon microsphere anode material, characterized in that, Mesophase carbon microsphere precursor and acetylene gas are simultaneously introduced into a pyrolysis furnace. The pyrolysis reaction of acetylene gas and the carbonization reaction of mesophase microsphere precursor are carried out simultaneously to obtain acetylene carbon black mesophase carbon microsphere anode material. The mesophase carbon microsphere precursor is prepared using benzene. The preparation of the mesophase carbon microsphere precursor using benzene includes the following steps: (1) Dehydrogenation cyclization reaction: Benzene vapor is passed into a fluidized bed reactor with platinum and palladium as catalyst system. The temperature inside the reactor is controlled at 500~600°C and the pressure is controlled at 0.5~1.5 MPa. The reaction product is condensed to obtain a liquid phase substance. (2) Polycondensation to form mesophase carbon microsphere precursor: The liquid phase material formed in step (1) is condensed and then introduced into the reactor. The reaction temperature is 400~500°C and the reaction pressure is 5~10 MPa. The reaction yields mesophase carbon microsphere precursor. In step (1), the fluidized bed reactor has two layers. The catalyst in the first layer of the fluidized bed is a platinum and palladium catalyst, and the catalyst in the second layer of the fluidized bed is a mixture of platinum, palladium and zeolite. The mass ratio of platinum, palladium and zeolite is (1~0.5):(1~0.5):(1~2).
2. The method for preparing an acetylene black mesophase carbon microsphere anode material according to claim 1, characterized in that, In step (2), zirconium oxide sulfate powder catalyst is added.
3. The method for preparing an acetylene black mesophase carbon microsphere anode material according to claim 1, characterized in that, In step (2), 1-butyl-3-methylimidazolium chloride is also added as a solvent.
4. The method for preparing an acetylene black mesophase carbon microsphere anode material according to claim 2, characterized in that, The reactor in step (2) is a tubular reactor with a spiral stirring device inside.
5. The method for preparing an acetylene black mesophase carbon microsphere anode material according to claim 1, characterized in that, After the reaction in step (2) is completed, the mesophase carbon microsphere precursor is separated by high-speed centrifugation filtration or by a membrane filtration method.
6. The method for preparing an acetylene black mesophase carbon microsphere anode material according to claim 4, characterized in that, First, filter the sulfated zirconium oxide powder, then separate the mesophase carbon microsphere precursor through high-speed centrifugal filtration or filtration membrane.