A method of producing activated carbon, activated carbon and an electrode

Abstract

This invention provides a method for preparing activated carbon, activated carbon, and an electrode. The method includes the following steps: Step (1): mixing a metal-organic framework and an oil slurry to obtain a mixture; Step (2): subjecting the obtained mixture to coking treatment to obtain petroleum coke; Step (3): subjecting the obtained petroleum coke to carbonization treatment to obtain an activated carbon precursor; Step (4): subjecting the obtained activated carbon precursor to activation treatment, followed by a second carbonization treatment to obtain the activated carbon. The activated carbon prepared by the method of this invention has a high specific capacitance, as well as a high specific surface area and pore volume. This activated carbon can be used to prepare an electrochemical capacitor electrode, which can effectively improve the specific capacitance of the capacitor.

Description

Technical Field

[0001] This invention belongs to the field of activated carbon preparation technology, specifically relating to a method for preparing activated carbon, activated carbon, and an electrode. Background Technology

[0002] Electrochemical capacitors are a new type of electrochemical energy storage device developed in recent years. They possess high energy density and excellent fast charge / discharge performance, showing potential application value in electric vehicles, power tools, and mobile communications. Carbon materials, as electrode materials for electrochemical capacitors, offer advantages such as good electrical and thermal conductivity, stable chemical properties, a small coefficient of thermal expansion, low cost, and ease of industrial production, making them the most promising electrode materials for electrochemical capacitors. Currently, oil refineries and coal coking processes generate large quantities of low-value-added heavy oil. This heavy oil, with its high carbon content and low price, can serve as an ideal raw material for activated carbon. However, activated carbon produced using conventional methods exhibits poor performance, such as low specific capacitance, low specific surface area, and low pore volume. Summary of the Invention

[0003] To address at least one problem existing in the prior art, the present invention provides a method for preparing activated carbon, activated carbon, and an electrode. The activated carbon prepared by the method of the present invention has a high specific surface area and pore volume, and has a suitable pore size, which is beneficial for electrolyte wetting. The activated carbon used as an electrode in an electrochemical capacitor has a high specific capacitance.

[0004] In a first aspect, the present invention provides a method for preparing activated carbon, the method comprising the following steps.

[0005] Step (1): Mix the metal-organic framework and the oil slurry to obtain a mixture.

[0006] Step (2): The obtained mixture is subjected to coking treatment to obtain petroleum coke.

[0007] Step (3): Carbonize the obtained petroleum coke to obtain activated carbon precursor.

[0008] Step (4): The obtained activated carbon precursor is activated to obtain the activated carbon.

[0009] Preferably, the specific surface area of ​​the metal-organic framework is ≥500 m². 2 / g, preferably 500-1500m 2 / g.

[0010] Preferably, the pore volume of the metal-organic framework is ≥0.2 cm³. 3 / g, preferably 0.3-1.2cm 3 / g.

[0011] Preferably, the pore size of the metal-organic framework is ≥0.2nm, and more preferably 0.2-5nm.

[0012] Preferably, the metal-organic framework includes at least one of IRMOF, CPL, ZIFs, MIL, and UiO.

[0013] Preferably, the density of the oil slurry is ≥0.9 g / cm³. 3 .

[0014] Preferably, the slurry comprises at least one of catalytic cracking slurry, high-end carbon heavy oil slurry, asphalt, and residual oil.

[0015] Preferably, the weight ratio of the metal-organic framework to the slurry is 1:6-150, more preferably 1:10-120.

[0016] Preferably, in step (1), the mixing conditions include: a mixing temperature of 50-160℃, preferably 100-140℃; and a mixing time of 1-3h, preferably 1.5-2.5h.

[0017] Preferably, the mixture obtained in step (1) is cooled to room temperature before step (2).

[0018] Preferably, in step (2), the coking process includes: performing a first coking process on the mixture under a first coking condition, then performing a second coking process under a second coking condition, and obtaining the petroleum coke after cooling.

[0019] Preferably, the first coking conditions include: a first coking temperature of 200-300℃, more preferably 240-290℃; and a first coking time of 1-5h, more preferably 1.5-3h.

[0020] Preferably, step (2) further includes: before the first coking treatment, at 1-10℃ min -1 The mixture from step (1) is heated to the first coking temperature at a rate of 2-8°C / min; preferably at 2-8°C / min. -1 The temperature is increased at a rate to the first coking temperature.

[0021] Preferably, the second coking conditions include: a second coking temperature of 450-550℃, more preferably 490-510℃; and a second coking time of 8-20h, more preferably 10-15h.

[0022] Preferably, step (2) further includes: before the second coking treatment, at 1-10℃ min -1 The material after the first coking treatment is heated from the first coking temperature to the second coking temperature at a rate of 1.5-5℃ / min; preferably, this rate is 1.5-5℃ / min.-1 The temperature is increased at a rate to the second coking temperature.

[0023] Preferably, the carbonization process in step (3) is carried out in an argon-hydrogen mixed atmosphere or an inert atmosphere; more preferably, it is carried out in an argon-hydrogen mixed atmosphere.

[0024] Preferably, the carbonization conditions include: a carbonization temperature of 400-1000℃, more preferably 500-900℃; and a carbonization time of 0.5-300 min, more preferably 50-200 min.

[0025] Preferably, step (3) further includes: before the carbonization treatment, heating the petroleum coke obtained in step (2) at 0.5-10℃ min. -1 The temperature is increased to the carbonization temperature at a rate of 1-5°C / min, preferably 1-5°C / min. -1 The temperature is increased to the carbonization temperature at a rate that allows it to rise.

[0026] More preferably, step (3) further includes: grinding the petroleum coke obtained in step (2) before heating it, wherein the particle size after grinding is 0.18-0.4 mm, preferably 0.2-0.3 mm.

[0027] Preferably, step (3) further includes: cooling the activated carbon precursor obtained by carbonization to room temperature.

[0028] Preferably, in step (4), the activation treatment method includes: immersing the activated carbon precursor in an activator solution, and then taking it out and activating it.

[0029] Preferably, the activation conditions include: an activation temperature of 400-1000℃, more preferably 600-950℃; and an activation time of 0.5-600 min, more preferably 60-500 min.

[0030] More preferably, the activation treatment in step (4) further includes: before activation, activating the activated carbon precursor taken from the activator solution at 0.5-10°C for min. -1 The temperature is increased to the activation temperature at a rate of 2-8°C / min; preferably at a rate of 2-8°C / min. -1 The temperature is increased at a rate to the activation temperature.

[0031] More preferably, the activation treatment method in step (4) further includes: drying the activated carbon precursor taken from the activator solution and then heating it.

[0032] Preferably, the activator includes at least one selected from sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate.

[0033] Preferably, the weight ratio of the activated carbon precursor to the activator is 1:0.2-50, more preferably 1:5-15.

[0034] Preferably, the concentration of the activator solution is 1-20g / 100ml, more preferably 2-15g / 100ml.

[0035] Preferably, the soaking time is 5-30 hours, more preferably 8-20 hours.

[0036] Preferably, step (4) further includes: cooling and washing the activated carbon obtained from the activation treatment.

[0037] Preferably, the washing method involves sequential acid washing and water washing.

[0038] More preferably, the number of pickling cycles is 3-5 times, and the number of water washing cycles is 3-5 times.

[0039] Secondly, the present invention provides activated carbon prepared by the method described in the first aspect.

[0040] Preferably, the N content in the activated carbon is 0.1-15% by weight, more preferably 1-8%, and even more preferably 1.5-3%.

[0041] Preferably, the activated carbon has a pore volume of 0.1-2.1 cm. 3 / g, preferably 0.5-0.7cm 3 / g.

[0042] Preferably, the specific surface area of ​​the activated carbon is 300-2000 m². 2 / g, preferably 1000-1500m 2 / g.

[0043] Thirdly, the present invention provides an electrode for an electrochemical capacitor, the electrode comprising the activated carbon described in the second aspect.

[0044] Preferably, the electrode further includes a conductive agent, a binder, and a conductive substrate.

[0045] More preferably, the weight ratio of the activated carbon, the conductive agent, and the binder is 4-12:0.5-3:1, and more preferably 6-10:0.5-2:1.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The activated carbon prepared by this invention possesses structural advantages such as porosity, impurity atom (e.g., N) doping, and a large specific surface area, resulting in excellent electrochemical performance. Electrochemical capacitor electrodes prepared using the activated carbon of this invention exhibit excellent specific capacitance (at 1 A g). -1The specific capacitance at current density can reach 150.3 F / g. This invention provides a new approach for developing electrochemical capacitor electrode materials with excellent comprehensive performance. Attached Figure Description

[0048] Figure 1 The XRD (X-ray diffraction) pattern of the activated carbon in Example 1 of this invention;

[0049] Figure 2 This is the Raman spectrum of the activated carbon in Example 1 of the present invention. Detailed Implementation

[0050] The present invention will be further described below with reference to specific embodiments, but this does not constitute any limitation on the present invention.

[0051] The inventors of this invention have discovered that by compounding a metal-organic framework (MOF) with an oil slurry, followed by coking, carbonization, and activation treatments, the prepared activated carbon exhibits a larger specific surface area and pore volume. The activated carbon of this invention, when used as an electrode in an electrochemical capacitor, demonstrates excellent electrochemical performance (specific capacitance). Analysis suggests that the compounding of the MOF with the oil slurry works synergistically to effectively increase the specific surface area. Furthermore, it is believed that the metal atoms and impurity atoms (such as N, O, and S) introduced by the MOF can give the activated carbon a larger active surface area, resulting in higher specific capacitance when used as an electrode in an electrochemical capacitor.

[0052] In a first aspect, the present invention provides a method for preparing activated carbon, the method comprising the following steps:

[0053] Step (1): Mix the metal-organic framework and the oil slurry to obtain a mixture;

[0054] Step (2): The obtained mixture is subjected to coking treatment to obtain petroleum coke;

[0055] Step (3): Carbonize the obtained petroleum coke to obtain activated carbon precursor;

[0056] Step (4): The obtained activated carbon precursor is activated to obtain the activated carbon.

[0057] In this invention, the metal-organic framework has a suitable pore structure and specific surface area, which can not only effectively improve the electrochemical performance of activated carbon, but also enable flexible control of the pore structure of activated carbon, thereby expanding the application range of activated carbon.

[0058] In a preferred embodiment of the present invention, the metal-organic framework has a specific surface area ≥ 500 m². 2 / g, preferably 500-1500m 2 / g; and / or, the pore volume of the metal-organic framework is ≥0.2cm³.3 / g, preferably 0.3-1.2cm 3 / g; and / or, the pore size of the metal-organic framework is ≥0.2nm, preferably 0.2-5nm.

[0059] In a preferred embodiment of the present invention, the metal-organic framework includes at least one of IRMOF, CPL, ZIFs, MIL, and UiO; preferably, the ZIFs are selected from ZIFs and / or IRMOF.

[0060] The IRMOF is composed of separate secondary structural units [Zn4O]. 6+ Inorganic groups and a series of aromatic carboxylic acid ligands form a microporous crystalline material that is self-assembled in an octahedral bridge; the CPL is formed by coordination of a six-coordinate metal element with a neutral nitrogen-containing heterocyclic ligand; ZIFs are zeolite-like materials synthesized by reacting Zn(III) or Co(III) with imidazole ligands; the MIL is a material synthesized using different transition metal elements and dicarboxylic acid ligands; UiO is a material with a three-dimensional microporous structure formed by connecting a Zr (zirconium)-containing regular octahedron [Zr6O4(OH)4] with a terephthalic acid (BDC) organic ligand.

[0061] In this invention, the metal-organic framework can be purchased from commercially available products or prepared in-house, and the preparation method can be a conventional method in the art.

[0062] In this invention, the oil slurry refers to a heavy byproduct obtained during crude oil refining. Preferably, the density of the oil slurry is ≥0.9 g / cm³. 3 .

[0063] In a preferred embodiment of the present invention, the slurry includes at least one of catalytic cracking slurry, high-end carbon heavy oil slurry, asphalt, and residual oil, preferably at least one of high-end carbon heavy oil slurry, residual oil, and catalytic cracking slurry.

[0064] The catalytic cracking slurry refers to the heavy oil component obtained during petroleum refining through catalytic cracking followed by solidification treatment, with a density of 0.96-1.05 g / cm³. 3 .

[0065] The high-end carbon heavy oil slurry refers to the heavy oil component obtained from the bottom of the catalytic cracking slurry after processing by a vacuum unit, with a density of 1-1.14 g / cm³. 3 .

[0066] The asphalt is a heavy oil slurry obtained from the bottom of the catalytic cracking slurry tower after treatment by the vacuum distillation unit, with a density of 1.19-1.22 g / cm³. 3 .

[0067] The residue oil is the bottom heavy oil slurry of the catalytic cracking slurry after slurry-bed hydrotreating, with a density of 1.17-1.19 g / cm³. 3 .

[0068] In a preferred embodiment of the present invention, the weight ratio of the metal-organic framework to the oil slurry is 1:6-150, preferably 1:10-120, and more preferably 1:15-50. Using this preferred ratio not only effectively improves the electrochemical performance of activated carbon but also allows for flexible control of the specific surface area and pore structure of the activated carbon.

[0069] In a preferred embodiment of the present invention, in step (1), the mixing conditions include: a mixing temperature of 50-160°C, preferably 100-140°C; and a mixing time of 1-3 hours, preferably 1.5-2.5 hours.

[0070] In a preferred embodiment of the present invention, the mixture obtained in step (1) is cooled to room temperature before step (2).

[0071] In a preferred embodiment of the present invention, step (2) of the coking process includes: performing a first coking process on the mixture under a first coking condition, then performing a second coking process under a second coking condition, and obtaining the petroleum coke after cooling.

[0072] In a preferred embodiment of the present invention, the first coking conditions include: a first coking temperature of 200-300℃, preferably 240-290℃; and a first coking time of 1-5h, preferably 1.5-3h.

[0073] In a preferred embodiment of the present invention, step (2) further includes: before the first coking treatment, at 1-10℃ min -1 The mixture from step (1) is heated to the first coking temperature at a rate of 2-8°C / min; preferably at 2-8°C / min. -1 The temperature is increased at a rate to the first coking temperature.

[0074] In a preferred embodiment of the present invention, the second coking conditions include: a second coking temperature of 450-550℃, preferably 490-510℃; and a second coking time of 8-20h, preferably 10-15h.

[0075] In a preferred embodiment of the present invention, step (2) further includes: before the second coking treatment, at 1-10℃ min -1 The material after the first coking treatment is heated from the first coking temperature to the second coking temperature at a rate of 1.5-5℃ / min; preferably, this rate is 1.5-5℃ / min. -1 The temperature is increased at a rate to the second coking temperature.

[0076] In a preferred embodiment of the present invention, the carbonization treatment in step (3) is carried out in an argon-hydrogen mixed atmosphere or an inert atmosphere; preferably, it is carried out in an argon-hydrogen mixed atmosphere. In the argon-hydrogen mixed atmosphere, the ratio of argon to hydrogen is 15-20:1.

[0077] In a preferred embodiment of the present invention, the inert atmosphere is selected from at least one of helium, neon, argon, krypton, xenon, and nitrogen.

[0078] In a preferred embodiment of the present invention, the carbonization treatment conditions include: a carbonization temperature of 400-1000℃, preferably 500-900℃; and a carbonization time of 0.5-300 min, preferably 50-200 min.

[0079] In a preferred embodiment of the present invention, step (3) further includes: before the carbonization treatment, the petroleum coke obtained in step (2) is heated at 0.5-10℃ for a period of time. -1 The temperature is increased to the carbonization temperature at a rate of 1-5°C / min, preferably 1-5°C / min. -1 The temperature is increased to the carbonization temperature at a rate that allows it to rise.

[0080] In a preferred embodiment of the present invention, step (3) further includes: before heating the petroleum coke obtained in step (2), grinding the petroleum coke, wherein the particle size after grinding is 0.18-0.4 mm, preferably 0.2-0.3 mm.

[0081] In a preferred embodiment of the present invention, step (3) further includes: cooling the activated carbon precursor obtained by carbonization to room temperature.

[0082] In a preferred embodiment of the present invention, step (4) includes immersing the activated carbon precursor obtained in step (3) in an activator solution, and then taking it out and activating it.

[0083] In a preferred embodiment of the present invention, the activation conditions include: an activation temperature of 400-1000℃, preferably 600-950℃; and an activation time of 0.5-600 min, preferably 60-500 min.

[0084] In a preferred embodiment of the present invention, the activation treatment method in step (4) further includes: before activation, the activated carbon precursor taken from the activator solution is heated at 0.5-10℃ for min. -1 The temperature is increased to the activation temperature at a rate of 2-8°C / min; preferably at a rate of 2-8°C / min. -1 The temperature is increased at a rate to the activation temperature.

[0085] In a preferred embodiment of the present invention, the activation treatment method in step (4) further includes: drying the activated carbon precursor taken from the activator solution and then heating it.

[0086] In a preferred embodiment of the present invention, the activator includes at least one selected from sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate; preferably sodium hydroxide or potassium hydroxide.

[0087] In a preferred embodiment of the present invention, the weight ratio of the activated carbon precursor to the activator is 1:0.2-50, preferably 1:5-15.

[0088] In a preferred embodiment of the present invention, the concentration of the activator solution is 1-20g / 100ml, preferably 2-15g / 100ml.

[0089] In a preferred embodiment of the present invention, the soaking time is 5-30 hours, preferably 8-20 hours.

[0090] In a preferred embodiment of the present invention, step (4) further includes: cooling and washing the activated carbon obtained by the activation treatment.

[0091] In a preferred embodiment of the present invention, the washing method is to perform acid washing and water washing in sequence.

[0092] In a preferred embodiment of the present invention, the number of acid washings is 3-5 times, and the number of water washings is 3-5 times.

[0093] In this invention, the acid used for pickling is selected from hydrochloric acid or nitric acid; and / or, the concentration of the acid is 5-15 wt%.

[0094] Secondly, the present invention provides activated carbon prepared by the method described in the first aspect.

[0095] In a preferred embodiment of the present invention, the N content in the activated carbon is 0.1-15% by weight, preferably 1-8%, and more preferably 1.5-3%.

[0096] In a preferred embodiment of the present invention, the activated carbon has a pore volume of 0.1-2.1 cm³. 3 / g, preferably 0.5-0.7cm 3 / g.

[0097] In a preferred embodiment of the present invention, the specific surface area of ​​the activated carbon is 300-2000 m². 2 / g, preferably 1000-1500m 2 / g.

[0098] In a preferred embodiment of the present invention, the activated carbon has a pore size of 0.1-50 nm, preferably 1-15 nm, and more preferably 2-5 nm.

[0099] In this invention, the pore size is measured using methods commonly used in the art, such as using the BET method to obtain a pore size distribution map with a single peak, and the horizontal axis corresponding to the peak value in the pore size distribution map is identified as the pore size of the activated carbon.

[0100] In this invention, the activated carbon has the above-mentioned preferred N content, pore volume, specific surface area and pore size, and when used as an electrode of an electrochemical capacitor, the electrode has a superior specific capacitance.

[0101] Thirdly, the present invention provides an electrode for an electrochemical capacitor, the electrode being made of activated carbon as described in the second aspect.

[0102] In a preferred embodiment of the present invention, the electrode further includes a conductive agent, a binder, and a conductive substrate.

[0103] In a preferred embodiment of the present invention, the weight ratio of the activated carbon, the conductive agent and the binder is 4-12:0.5-3:1, preferably 6-10:0.5-2:1.

[0104] In this invention, the conductive agent can be a commonly used conductive agent in the art, such as acetylene black or graphene.

[0105] In this invention, the adhesive can be a commonly used adhesive in the art, such as polytetrafluoroethylene.

[0106] In this invention, the conductive substrate can be a commonly used conductive substrate in the art, such as nickel foam, nickel sheet, stainless steel felt, or stainless steel mesh.

[0107] In this invention, the specific capacitance of the electrode is determined using conventional electrochemical testing methods in the art, such as cyclic voltammetry, including the following steps:

[0108] a. Electrode preparation: The activated carbon, acetylene black and polytetrafluoroethylene are mixed in a mass ratio of 8:1:1 and spread evenly on nickel foam, and then pressed into a circular electrode.

[0109] b. Electrode Testing: Under room temperature conditions, a three-electrode system was used. The reference electrode was a saturated calomel electrode, the auxiliary electrode was a platinum electrode, and the electrolyte solution was a 30% KOH solution. The original sheet electrode was immersed in the electrolyte solution for 1 hour before testing began.

[0110] c. Cyclic voltammetry tests were performed using an Ivium-n-Stat electrochemical workstation.

[0111] The following detailed description of preferred embodiments of the present invention illustrates the principles of the invention and is not intended to limit the scope of the invention.

[0112] The nitrogen content in activated carbon was obtained using XPS elemental analysis.

[0113] The pore volume and pore size of activated carbon were obtained by BET method; in the pore size test, a peak appeared in the pore size distribution diagram, and the horizontal axis corresponding to the peak value was identified as the pore size of activated carbon.

[0114] Specific capacitance was determined using a DH7000 electrochemical workstation via cyclic voltammetry.

[0115] High-end carbon heavy oil slurry: The heavy oil component obtained from the bottom of the catalytic cracking slurry after processing by a vacuum unit, with a density of 1.12 g / cm³. 3 ;

[0116] Residue oil: Heavy oil slurry from the bottom of the tower after crude oil has undergone slurry bed hydrotreating, with a density of 1.18 g / cm³. 3 ;

[0117] Vacuum residue: The residual oil obtained from crude oil through vacuum distillation, with a density of 0.98 g / cm³. 3 ;

[0118] ZIF-8 (CAS: 59061-53-9) was purchased from Xi'an Qiyue Biotechnology.

[0119] ZIF-67 (CAS:46201-07-4), purchased from Xi'an Qiyue Biotechnology;

[0120] Needle coke: specific surface area 8.3 m² 2 / g, pore size 0.4-4nm, pore volume 0.11cm³ 3 / g;

[0121] In the following examples and comparative examples, the parts by weight are (g) and the parts by volume are (ml).

[0122] Example 1

[0123] The preparation process and steps in this embodiment are as follows:

[0124] Step (1): Add 0.5 parts by weight of ZIF-8 (CAS:59061-53-9) to 11 parts by weight of high-end carbon heavy oil slurry at 120℃ and stir for 2 hours. Then cool the product to room temperature to obtain the mixture.

[0125] Step (2): In a coke oven, the prepared mixture is heated at 5°C for 5 minutes. -1 The temperature is increased to 280℃ at a rate of [missing information] and held for 2 hours to complete the first coking treatment, and then [missing information] is increased at 3℃ / min.-1 The temperature is increased to 500℃ and held for 12 hours to complete the second raw coke treatment. After cooling to room temperature, petroleum coke is obtained.

[0126] Step (3): Grind the obtained petroleum coke to a particle size of 0.2-0.3 mm, then take 10 parts by weight and place them in a tube furnace filled with argon-hydrogen gas (the volume ratio of argon to hydrogen is 18:1), and heat at 2℃ for 1 minute. -1 The temperature was increased to 600℃ at a rate of 120 min and held for 120 min to complete carbonization. After cooling, activated carbon precursor was obtained.

[0127] Step (4): Place 3 parts by weight of activated carbon precursor in 300 parts by volume of potassium hydroxide solution (the mass of potassium hydroxide in the solution is 30 parts by weight) and immerse for 12 hours. Then dry and place in a tube furnace filled with argon-hydrogen gas (the volume ratio of argon to hydrogen is 18:1) and heat at 5°C for 1 minute. -1 The temperature was increased to 800℃ and held for 200 min to complete the activation. After cooling to room temperature, the activated carbon M1 was prepared by washing it 4 times with dilute hydrochloric acid (7% by mass) and then washing it 4 times with distilled water.

[0128] The results of the detection of N content, pore volume, specific surface area and pore size of activated carbon M1 are shown in Table 1.

[0129] Example 2

[0130] Activated carbon was prepared according to the method of Example 1, except that in step (1), ZIF-8 (CAS:59061-53-9) was replaced with an equal amount of ZIF-67 (CAS:46201-07-4).

[0131] Activated carbon M2 was prepared.

[0132] The results of the detection of N content, pore volume, specific surface area and pore size of activated carbon M2 are shown in Table 1.

[0133] Example 3

[0134] Activated carbon was prepared according to the method of Example 1, except that in step (1), the amount of ZIF-8 (CAS: 59061-53-9) was 0.3 parts by weight.

[0135] Activated carbon M3 was prepared.

[0136] The results of the detection of N content, pore volume, specific surface area and pore size of activated carbon M3 are shown in Table 1.

[0137] Example 4

[0138] Step (1): Add 0.5 parts by weight of ZIF-8 (CAS:59061-53-9) to 5 parts by weight of residue oil at 100℃ and stir for 1.5 hours. Then cool the product to room temperature to obtain a mixture.

[0139] Step (2): In a coke oven, the prepared mixture is heated at 2°C for 2 minutes. -1 The temperature is increased to 240℃ at a rate of [missing information] and held for 3 hours to complete the first coking treatment, and then [missing information] is increased at 5℃ / min [missing information]. -1 The temperature was increased to 510℃ and held for 10 hours to complete the second raw coke treatment. The coke was then cooled to room temperature to obtain petroleum coke.

[0140] Step (3): Grind the obtained petroleum coke to a particle size of 0.2-0.3 mm, then take 10 parts by weight and place them in a tube furnace filled with argon-hydrogen gas (the volume ratio of argon to hydrogen is 18:1), and heat at 5℃ for 1 minute. -1 The temperature was increased to 500℃ at a certain rate and held for 200 min to complete carbonization. After cooling, activated carbon precursor was obtained.

[0141] Step (4): Place 3 parts by weight of the activated carbon precursor in 300 parts by volume of potassium hydroxide solution (the mass of potassium hydroxide in the solution is 45 parts by weight) and immerse for 8 hours. Then dry it and place it in a tube furnace filled with argon-hydrogen gas (the volume ratio of argon to hydrogen is 18:1) and heat at 2°C for 1 minute. -1 The temperature was increased to 600℃ and held for 500 min to complete the activation. After cooling to room temperature, the activated carbon M4 was prepared by washing it four times with dilute hydrochloric acid (7% by mass) and then washing it four times with distilled water.

[0142] The results of the detection of N content, pore volume, specific surface area and pore size of activated carbon M4 are shown in Table 1.

[0143] Example 5

[0144] Step (1): Add 0.5 parts by weight of ZIF-8 (CAS:59061-53-9) to 15 parts by weight of high-end carbon heavy oil slurry (heavy oil slurry) at 140℃ and stir for 2.5h. Then cool the product to room temperature to obtain a mixture.

[0145] Step (2): In a coke oven, the prepared mixture is heated at 8°C for 1 minute. -1 The temperature is increased to 290℃ at a rate of [missing information] and held for 1.5 hours to complete the first coking treatment, and then [missing information] is increased at 1.5℃ per minute. -1 The temperature was increased to 490℃ and held for 15 hours to complete the second raw coke treatment. The coke was then cooled to room temperature to obtain petroleum coke.

[0146] Step (3): Grind the obtained petroleum coke to a particle size of 0.2-0.3 mm, then take 10 parts by weight and place them in a tube furnace filled with argon-hydrogen gas (the volume ratio of argon to hydrogen is 18:1), and heat at 1℃ for 1 minute. -1 The temperature was increased to 900℃ at a rate of 100℃ and held for 50 min to complete carbonization. After cooling, activated carbon precursor was obtained.

[0147] Step (4): Place 3 parts by weight of the activated carbon precursor in 300 parts by volume of potassium hydroxide solution (the mass of potassium hydroxide in the solution is 15 parts by weight) and immerse for 20 hours. Then dry it and place it in a tube furnace filled with argon-hydrogen gas (the volume ratio of argon to hydrogen is 18:1) and heat at 8°C for 1 minute. -1 The temperature was increased to 950℃ and held for 50 minutes to complete the activation. After cooling to room temperature, the activated carbon M5 was prepared by washing it four times with dilute hydrochloric acid (7% by mass) and then washing it four times with distilled water.

[0148] The results of the detection of N content, pore volume, specific surface area and pore size of activated carbon M5 are shown in Table 1.

[0149] Example 6

[0150] Activated carbon was prepared according to the method of Example 1, except that in step (1), the amount of high-end carbon heavy oil slurry (heavy oil slurry) used was 2.5 parts by weight.

[0151] Activated carbon M6 was prepared.

[0152] The results of the detection of N content, pore volume, specific surface area and pore size of activated carbon M6 are shown in Table 1.

[0153] Example 7

[0154] Activated carbon was prepared according to the method of Example 1, except that in step (1), heavy oil slurry (high-end carbon heavy oil slurry) was replaced with an equal amount of vacuum residue.

[0155] Activated carbon M7 was prepared.

[0156] The results of the detection of N content, pore volume, specific surface area and pore size of activated carbon M7 are shown in Table 1.

[0157] Example 8

[0158] Activated carbon was prepared according to the method of Example 1, except that in step (2), the prepared mixture was heated at 15°C for 1 minute. -1 The temperature was increased to 450℃ and held for 6 hours to complete the first coking process.

[0159] Activated carbon M8 was prepared.

[0160] The results of the detection of N content, pore volume, specific surface area and pore size of activated carbon M8 are shown in Table 1.

[0161] Example 9

[0162] Activated carbon was prepared according to the method of Example 1, except that in step (2), the temperature was increased to 15°C for 1 minute. -1 The temperature is increased to 600℃ and held for 5 hours to complete the second coking process.

[0163] Activated carbon M9 was prepared.

[0164] The results of the detection of N content, pore volume, specific surface area and pore size of activated carbon M9 are shown in Table 1.

[0165] Example 10

[0166] Activated carbon was prepared according to the method in Example 1, except that in step (3), the temperature was increased to 15°C for 1 minute. -1 The temperature was increased to 1100℃ at a certain rate and held for 350 minutes to complete carbonization.

[0167] Activated carbon M10 was prepared.

[0168] The results of the detection of N content, pore volume, specific surface area and pore size of activated carbon M10 are shown in Table 1.

[0169] Example 11

[0170] Activated carbon was prepared according to the method of Example 1, except that in step (4), the temperature was increased to 15°C for 1 minute. -1 The temperature was increased to 1100℃ and held for 700 minutes to complete the activation.

[0171] Activated carbon M11 was prepared.

[0172] The results of the detection of N content, pore volume, specific surface area and pore size of activated carbon M11 are shown in Table 1.

[0173] Example 12

[0174] Activated carbon was prepared according to the method of Example 1, except that in step (2), the first coking treatment was not performed. Instead, the prepared mixture was directly heated at 2°C / min in a coking oven. -1 The temperature is increased to 500℃ and held for 12 hours to complete the second coking process.

[0175] Activated carbon M12 was prepared.

[0176] The results of the detection of N content, pore volume, specific surface area and pore size of activated carbon M12 are shown in Table 1.

[0177] Comparative Example 1

[0178] Activated carbon was prepared according to the method of Example 1, except that ZIF-8 (CAS: 59061-53-9) was not added in step (1).

[0179] Activated carbon D1 was prepared.

[0180] The results of the detection of N content, pore volume, specific surface area and pore size of activated carbon D1 are shown in Table 1.

[0181] Comparative Example 2

[0182] Activated carbon was prepared according to the method of Example 1, except that in step (1), ZIF-8 (CAS:59061-53-9) was replaced with an equal amount of needle coke.

[0183] Activated carbon D2 was prepared.

[0184] The results of the detection of N content, pore volume, specific surface area and pore size of activated carbon D2 are shown in Table 1.

[0185] Comparative Example 3

[0186] Activated carbon was prepared according to the method of Example 1, except that no oil slurry was added in step (1).

[0187] Activated carbon D3 was prepared.

[0188] The results of the detection of N content, pore volume, specific surface area and pore size of activated carbon D3 are shown in Table 1.

[0189] Test Example 1

[0190] X-ray diffraction analysis was performed on the activated carbon from the above examples and comparative examples.

[0191] The X-ray diffraction pattern of activated carbon M1 is as follows: Figure 1 As shown, from Figure 1 It can be seen that the crystallinity of activated carbon M1 is low, indicating that the degree of graphitization of the material is low.

[0192] Test Example 2

[0193] Raman spectroscopy analysis was performed on the activated carbon from the above examples and comparative examples.

[0194] The Raman spectrum of activated carbon M1 is as follows: Figure 2 As shown, from Figure 2 It can be seen that the two characteristic peaks of activated carbon M1 are located at 1345.4 cm⁻¹. -1 (D-band) and 1576.8cm -1(G band). The intensity ratio of these two characteristic peaks is approximately 0.23, indicating that MP-C still contains a large number of defects after calcination, which is beneficial for increasing the active sites for electrochemical reactions.

[0195] Test Example 3

[0196] Electrochemical tests were performed on the activated carbon from the above examples and comparative examples.

[0197] a. Electrode preparation: First, the activated carbon, acetylene black and polytetrafluoroethylene are mixed in a mass ratio of 8:1:1 and then spread evenly on the nickel foam, and then pressed into a circular electrode.

[0198] b. Electrode testing: Under room temperature conditions, a three-electrode system was used, with a saturated calomel electrode as the reference electrode, a platinum electrode as the auxiliary electrode, and a 30% KOH solution as the electrolyte solution. The disc electrode was first immersed in the electrolyte solution for 1 hour, and then the electrochemical performance was tested.

[0199] c. Cyclic voltammetry was performed using an Ivium-n-Stat electrochemical workstation to determine 1 A g. -1 Total specific capacitance at current density.

[0200] The test results are shown in Table 1.

[0201] Table 1

[0202]

[0203] As shown in Table 1, the activated carbon prepared in this invention exhibits a high specific capacitance for electrochemical capacitor electrodes, with a capacitance of 1 Ag. -1 The specific capacitance at current density can reach 150.3 F / g.

[0204] Compared to Example 2, which uses ZIF-67 and high-end carbon heavy oil slurry to prepare activated carbon, Example 7, which uses ZIF-8 and vacuum residue to prepare activated carbon, and Comparative Example 2, which uses needle coke and high-end carbon heavy oil slurry to prepare activated carbon, Example 1 uses ZIF-8 and high-end carbon heavy oil slurry to prepare activated carbon, which has a larger specific surface area and pore volume, and a pore size of 2.1 nm. The electrode used to prepare it has a higher specific capacitance.

[0205] Compared to Comparative Example 3, which used ZIF-8 alone to prepare activated carbon, the activated carbon prepared in Example 1 using a blend of ZIF-8 and oil slurry exhibited a higher specific capacitance when used as an electrode in an electrochemical capacitor. Analysis suggests that while the activated carbon prepared using a metal-organic framework alone had a higher specific surface area (reaching 1612.4 m²), the latter was less effective. 2However, an excessively high specific surface area results in too many internal voids, making it difficult for the electrolyte to fully wet the surface, thus reducing the effective area and consequently lowering the specific capacitance.

[0206] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for preparing activated carbon, characterized in that, The method includes the following steps: Step (1): Mix the metal-organic framework and the oil slurry to obtain a mixture; Step (2): The obtained mixture is subjected to coking treatment to obtain petroleum coke; Step (3): Carbonize the obtained petroleum coke to obtain activated carbon precursor; Step (4): The obtained activated carbon precursor is activated to obtain the activated carbon.

2. The method according to claim 1, characterized in that, The specific surface area of ​​the metal-organic framework is ≥500 m². 2 / g, preferably 500-1500m 2 / g; And / or, the pore volume of the metal-organic framework is ≥0.2 cm³. 3 / g, preferably 0.3-1.2cm 3 / g; And / or, the pore size of the metal-organic framework is ≥0.2 nm, preferably 0.2-5 nm; And / or, the metal-organic framework includes at least one of IRMOF, CPL, ZIFs, MIL and UiO; And / or, the density of the oil slurry is ≥0.9 g / cm³. 3 ; And / or, the slurry includes at least one of catalytic cracking slurry, high-end carbon heavy oil slurry, bitumen, and residual oil; And / or, the weight ratio of the metal-organic framework to the slurry is 1:6-150, preferably 1:10-120; And / or, in step (1), the mixing conditions include: a mixing temperature of 50-160°C, preferably 100-140°C; and a mixing time of 1-3 hours, preferably 1.5-2.5 hours. And / or, before proceeding to step (2), the mixture obtained in step (1) is cooled to room temperature.

3. The method according to claim 1 or 2, characterized in that, In step (2), the coking treatment method includes: performing a first coking treatment on the mixture under a first coking condition, then performing a second coking treatment under a second coking condition, and obtaining the petroleum coke after cooling; Preferably, the first coking conditions include: a first coking temperature of 200-300℃, more preferably 240-290℃; and a first coking time of 1-5 hours, more preferably 1.5-3 hours. Preferably, step (2) further includes: before the first coking treatment, at 1-10℃ min -1 The mixture from step (1) is heated to the first coking temperature at a rate of 2-8°C / min; preferably at 2-8°C / min. -1 The temperature is increased at a rate to the first coking temperature; And / or, the second coking conditions include: a second coking temperature of 450-550℃, preferably 490-510℃; and a second coking time of 8-20h, preferably 10-15h. Preferably, step (2) further includes: before the second coking treatment, at 1-10℃ min -1 The material after the first coking treatment is heated from the first coking temperature to the second coking temperature at a rate of 1.5-5℃ / min; preferably, this rate is 1.5-5℃ / min. -1 The temperature is increased at a rate to the second coking temperature.

4. The method according to any one of claims 1-3, characterized in that, The carbonization process described in step (3) is carried out in an argon-hydrogen mixed atmosphere or an inert atmosphere; preferably, it is carried out in an argon-hydrogen mixed atmosphere. And / or, the carbonization conditions include: a carbonization temperature of 400-1000℃, preferably 500-900℃; and a carbonization time of 0.5-300 min, preferably 50-200 min. Preferably, step (3) further includes: before the carbonization treatment, heating the petroleum coke obtained in step (2) at 0.5-10℃ for 1 minute. -1 The temperature is increased to the carbonization temperature at a rate of 1-5°C / min, preferably 1-5°C / min. -1 The temperature is increased to the carbonization temperature at a rate that allows it to rise. More preferably, step (3) further includes: grinding the petroleum coke obtained in step (2) before heating it, wherein the particle size after grinding is 0.18-0.4 mm, preferably 0.2-0.3 mm; And / or, step (3) further includes: cooling the activated carbon precursor obtained by carbonization to room temperature.

5. The method according to any one of claims 1-4, characterized in that, In step (4), the activation treatment method includes: immersing the activated carbon precursor in an activating agent solution, then taking it out and activating it; Preferably, the activation conditions include: an activation temperature of 400-1000℃, more preferably 600-950℃; and an activation time of 0.5-600 min, more preferably 60-500 min. More preferably, the activation treatment in step (4) further includes: before activation, activating the activated carbon precursor taken from the activator solution at 0.5-10°C for min. -1 The temperature is increased to the activation temperature at a rate of 2-8°C / min; preferably at a rate of 2-8°C / min. -1 The temperature is increased to the activation temperature at a rate that allows it to rise. More preferably, the activation treatment method in step (4) further includes: drying the activated carbon precursor taken from the activator solution and then heating it.

6. The method according to claim 5, characterized in that, The activator includes at least one of sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate. And / or, the weight ratio of the activated carbon precursor to the activator is 1:0.2-50, preferably 1:5-15; And / or, the concentration of the activator solution is 1-20 g / 100 ml, preferably 2-15 g / 100 ml; And / or, the impregnation time is 5-30 hours, preferably 8-20 hours.

7. The method according to any one of claims 1-6, characterized in that, Step (4) also includes: cooling and washing the activated carbon obtained from the activation treatment; Preferably, the washing method is to perform acid washing and water washing in sequence; More preferably, the number of pickling cycles is 3-5 times, and the number of water washing cycles is 3-5 times.

8. Activated carbon prepared by any one of claims 1-7.

9. The activated carbon according to claim 8, characterized in that, The activated carbon contains 0.1-15% N by weight, preferably 1-8%, and more preferably 1.5-3%. And / or, the pore volume of the activated carbon is 0.1-2.1 cm³. 3 / g, preferably 0.5-0.7cm 3 / g; And / or, the specific surface area of ​​the activated carbon is 300-2000 m². 2 / g, preferably 1000-1500m 2 / g.

10. An electrode for an electrochemical capacitor, characterized in that, The electrode comprises the activated carbon as described in claim 8 or 9; Preferably, the electrode further includes a conductive agent, a binder, and a conductive substrate; More preferably, the weight ratio of the activated carbon, the conductive agent, and the binder is 4-12: 0.5-3:1, preferably 6-10:0.5-2:1.

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