High-rate super capacitor carbon and preparation method thereof

Abstract

The invention discloses high-rate supercapacitor carbon and a preparation method thereof. The preparation method comprises the following steps: (1) performing organic intercalation treatment on kaolin to obtain organic kaolin; (2) uniformly mixing organic kaolin and asphalt, and then carrying out carbonization treatment; and (3) mixing the carbonized material with alkali for activating treatment, and then washing and drying to obtain the supercapacitor carbon. The invention also provides the high-magnification type super capacitor carbon obtained by adopting the preparation method. The high-rate super capacitor carbon obtained by the preparation method has the characteristics of large specific surface area, reasonable pore size distribution, high ion transmission rate and excellent rate capability.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon materials, and relates to supercapacitor carbon and a preparation method thereof. Background Art

[0002] A supercapacitor is a new type of energy storage device between traditional capacitors and rechargeable batteries, with a capacitance of several thousand to tens of thousands of farads. Compared with traditional capacitors, it has both a large capacitance and a high energy at the same time; compared with batteries, it has a higher specific power, a rapid response, a wide operating temperature range, an extremely long service life, and no pollution to the environment. A supercapacitor belongs to an efficient, practical, and environmentally friendly energy storage device.

[0003] Since the supercapacitor was put on the market, the global demand has expanded rapidly, and it has become a new industrial highlight in the field of chemical power sources. Supercapacitors not only have great application value and market potential in many fields such as new energy vehicles, rail transit, bus logistics, aerospace, medical equipment, power electrics, and consumer electronics, but also have extensive applications in aspects such as wind power pitch control, photovoltaic power generation, mechanical energy recovery, and smart city construction.

[0004] The wide application of supercapacitors benefits from the excellent properties of their electrode materials. The power density of supercapacitors is 30 to 100 times that of lithium-ion batteries. Compared with lithium-ion batteries, the advantages of supercapacitors are high power density and long cycle life. The power density is mainly related to the rate performance of the supercapacitor electrode material. The ways to improve the rate performance of the electrode material mainly include the regulation of the pore structure and the improvement of the material conductivity. A structure with larger pore diameters such as mesopores as channels is more conducive to the transmission of electrolyte ions. The improvement of the material conductivity generally adopts the method of adding conductive materials such as carbon nanotubes and graphene, but the addition process is relatively complex, and problems such as the uniformity of the material also have a relatively obvious impact on the overall capacitance performance of the material.

[0005] Carbon materials such as activated carbon, graphene, carbon nanotubes, and carbon aerogels are widely used in the construction of supercapacitor electrode materials. Patent CN106115694 A directly conducts high-temperature coking reduction and activation on graphene oxide and pitch coke together, so that graphene forms a conductive network inside the formed activated carbon, changing the problem of relatively high internal resistance of pitch-based activated carbon. However, when the addition amount of graphene is small, the improvement effect is not obvious. Increasing the addition amount of graphene will greatly increase the cost of the composite material, and the graphene oxide and pitch coke need to be mixed at high temperature repeatedly for many times in the early stage to ensure the uniformity of the conductive network in the composite material.

[0006] Patent CN105480962A discloses a preparation method of an in-situ self-assembled nitrogen-doped superhydrophilic carbon aerogel supercapacitor electrode material. A nitrogen-containing conductive polymer and a borate skeleton are introduced into the three-dimensional network structure of the gel, and a superhydrophilic high specific capacitance nitrogen-doped carbon aerogel supercapacitor electrode material with a hierarchical pore structure is prepared by high-temperature activation. The presence of the carbon aerogel is beneficial to power generation and the contact between the material and the electrolyte, promoting ion transport, thereby improving the capacitance performance. Patent CN110957148A prepared a nitrogen-doped carbon nanotube supercapacitor, and utilized the characteristics of the structurally uniform and stable carbon nanotubes with good conductivity to improve the capacitance performance of the composite material. Summary of the Invention

[0007] In view of the above problems existing in the prior art, the object of the present invention is to provide a high-rate supercapacitor carbon and its preparation method, so as to obtain a capacitive carbon with excellent rate performance, large specific surface area, reasonable pore size distribution and fast ion transport rate.

[0008] The first aspect of the present invention provides a preparation method of a high-rate supercapacitor carbon, comprising the following steps:

[0009] (1) Kaolin is subjected to organic intercalation treatment to obtain organic kaolin;

[0010] (2) Under contact conditions, the organic kaolin from step (1) is mixed uniformly with asphalt, and then carbonized;

[0011] (3) The carbonized material from step (2) is mixed with an alkali for activation treatment, and then the supercapacitor carbon is obtained after washing and drying.

[0012] Further, in the preparation method of the above high-rate supercapacitor carbon, the kaolin in step (1) is a 1:1 type layered silicate mineral. Further, its basic unit is a single-layer network formed by the connection of silicon-oxygen tetrahedra and aluminum-oxygen octahedra.

[0013] Further, in the preparation method of the above high-rate supercapacitor carbon, the organic intercalation treatment process in step (1) is to mix kaolin, an organic intercalating agent and a solvent uniformly for intercalation treatment, and then obtain organic kaolin after separation, washing and drying.

[0014] Further, in the preparation method of the above high-rate supercapacitor carbon, the organic intercalating agent is a strongly polar organic solvent, selected from one or more of dimethyl sulfoxide, tetradecyltrimethylammonium bromide, cetyltrimethylammonium bromide, methyl silicone oil, alkyl quaternary ammonium salts with 8-18 carbon atoms in the alkyl group, organic quaternary ammonium salts with hydroxyl or benzyl groups, acrylamide, silane coupling agent, phosphonium salts, preferably one or more of dimethyl sulfoxide, octadecyl quaternary ammonium salt, bis(octadecyl)benzyl quaternary ammonium salt.

[0015] Further, in the preparation method of the above high-rate supercapacitor carbon, the mass ratio of kaolin to the organic intercalating agent is 0.5:1 to 5:1, preferably 1:1 to 3:1.

[0016] Further, in the preparation method of the above high-rate supercapacitor carbon, the solvent is water and / or an organic solvent, and the organic solvent can specifically be selected from one or more of ethanol, acetone, propanol, benzene, and chloroform, preferably one or more of water and ethanol.

[0017] Further, in the preparation method of the above high-rate supercapacitor carbon, the mass ratio of kaolin to the solvent is 10:1 to 1:1, preferably 8:1 to 2:1.

[0018] Further, in the preparation method of the above high-rate supercapacitor carbon, the temperature of the intercalation treatment is 20 to 100 °C, preferably 40 to 90 °C.

[0019] Further, in the preparation method of the above high-rate supercapacitor carbon, the mixing can be carried out under ultrasonic conditions, and the ultrasonic mixing time is 4 to 20 h, preferably 6 to 12 h.

[0020] Further, in the preparation method of the above high-rate supercapacitor carbon, the washing is carried out by washing several times with deionized water, ultrapure water, ethanol, etc., and the liquid-solid mass ratio of the washing solvent to the solid-phase material during washing is 10:1 to 50:1, preferably 10:1 to 30:1.

[0021] Further, in the preparation method of the above high-rate supercapacitor carbon, the drying temperature is 40 to 100 °C, preferably 40 to 90 °C; the drying time is 1 to 48 h, preferably 6 to 24 h, and organic kaolin is obtained after drying is completed.

[0022] Further, in the preparation method of the above high-rate supercapacitor carbon, the organic intercalation treatment of kaolin in step (1) is to carry out organic intercalation between the closely stacked kaolin lamellae. The organic intercalating agent reduces the interlayer interaction, increases the interlayer spacing, and is more conducive to layer peeling.

[0023] Further, in the preparation method of the above high-rate supercapacitor carbon, before the organic kaolin is mixed with pitch, it is first uniformly mixed with a hydrocarbon-containing solvent. The hydrocarbon-containing solvent can be one or more of anthracene oil, gasoline, diesel, kerosene, toluene, and benzene. The mass ratio of organic kaolin to the hydrocarbon-containing solvent is 1:30 to 1:1, preferably 1:20 to 3:1.

[0024] Further, in the preparation method of the above high-rate supercapacitor carbon, the mixing process of organic kaolin and the hydrocarbon-containing solvent is carried out under stirring under ultrasonic conditions.

[0025] Further, in the preparation method of the above high-rate supercapacitor carbon, the temperature for mixing the organic kaolin with the hydrocarbon solvent is 40 to 200°C, preferably 60 to 150°C.

[0026] Further, in the preparation method of the above high-rate supercapacitor carbon, the mixing time of the organic kaolin with the hydrocarbon solvent is 1 to 10 h, preferably 2 to 6 h.

[0027] Further, in the preparation method of the above high-rate supercapacitor carbon, after mixing the organic kaolin with the hydrocarbon solvent in step (2), pitch is added for uniform mixing. Any one of the existing methods that can achieve uniform mixing of materials can be used. Specifically, methods such as melt blending, stirring, shearing, and ball milling can be adopted. Melt blending and high-speed shearing are preferred. Specifically, the shearing rate of the high-speed shearing machine during shearing mixing is 2000 to 8000 r / min, preferably 3000 to 6000 r / min, and the shearing mixing time is 0.2 to 3 h, preferably 0.5 to 2 h.

[0028] Further, in the preparation method of the above high-rate supercapacitor carbon, when adding the hydrocarbon solvent in step (2), the hydrocarbon solvent is recovered by rotary evaporation after the mixing process is completed.

[0029] Further, in the preparation method of the above high-rate supercapacitor carbon, the pitch in step (2) is one or more of petroleum pitch and coal pitch, preferably petroleum pitch, and more preferably mesophase pitch; the softening point of the pitch is 80 to 350°C, preferably 100 to 300°C.

[0030] Further, in the preparation method of the above high-rate supercapacitor carbon, the mass ratio of the pitch to the organic kaolin in step (2) is 100:1 to 1:1, preferably 50:1 to 3:1.

[0031] Further, in the preparation method of the above high-rate supercapacitor carbon, the temperature for co-blending after adding the pitch in step (2) is 50 to 250°C, preferably 80 to 300°C.

[0032] Further, in the uniform mixing process of step (2) of the above high-rate supercapacitor carbon preparation method, the high mixing and dispersion of pitch molecules and kaolin platelets are achieved through the action of the solvent. The platelet structure dispersed in the pitch matrix will hinder the movement of pitch molecular chains. At the same time, there are hydrogen bond and other interactions between the polar functional groups on the surface of kaolin and pitch molecules and micelles.

[0033] Further, in the preparation method of the above high-rate supercapacitor carbon, the carbonization treatment and activation treatment are carried out in the presence of an inert atmosphere, and the inert atmosphere can be one or more of nitrogen, helium, neon, argon, krypton, and xenon.

[0034] Further, in the preparation method of the above high-rate supercapacitor carbon, before carbonization treatment and activation treatment, the gas in the treatment device is usually fully replaced with an inert atmosphere to ensure that there is no oxygen in the treatment device.

[0035] Further, in the preparation method of the above high-rate supercapacitor carbon, in step (2), the carbonization treatment temperature is 200 - 650 °C, preferably 300 - 600 °C; further, the heating rate is controlled to be 1 - 20 °C / min, preferably 5 - 15 °C / min.

[0036] Further, in the preparation method of the above high-rate supercapacitor carbon, in step (2), the carbonization treatment time is 20 - 300 min, preferably 60 - 300 min.

[0037] Further, in the preparation method of the above high-rate supercapacitor carbon, after the carbonization treatment in step (2) is completed and cooled to room temperature, generally, the obtained solid material is crushed to a particle size of 10 - 100 μm, preferably 10 - 30 μm.

[0038] Further, in the preparation method of the above high-rate supercapacitor carbon, the base in step (3) is an inorganic base, which can be one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, potassium bicarbonate, sodium bicarbonate, calcium hydroxide, and magnesium hydroxide, preferably one or more of sodium hydroxide, potassium hydroxide, and potassium carbonate.

[0039] Further, in the preparation method of the above high-rate supercapacitor carbon, the base in step (3) is a granular solid, and the particle size of the base is 10 - 300 μm.

[0040] Further, in the preparation method of the above high-rate supercapacitor carbon, the activation treatment conditions in step (3) are as follows: the activation temperature is 600 - 1000 °C, preferably 700 - 900 °C; furthermore, the heating rate of activation is 1 - 10 °C / min, preferably 2 - 8 °C / min; the activation time is 20 - 180 min, preferably 20 - 120 min.

[0041] Further, in the preparation method of the above high-rate supercapacitor carbon, the weight ratio of the pitch in step (2) to the base in step (3) is 1:0.2 - 1:10, preferably 1:0.8 - 1:3.

[0042] Further, in the preparation method of the above high-rate supercapacitor carbon, the washing in step (3) includes three washing operations: alkali washing, water washing, and acid washing. The main purpose is to remove the residual kaolin and the alkaline substances generated by the reaction through alkali washing, water washing, and acid washing, and expose the rich pore structure formed during the activation process. The liquid-solid mass ratio of alkali washing is 10:1 to 50:1, preferably 10:1 to 30:1. The alkali washing temperature is 30 to 100 °C, preferably 60 to 100 °C. During the alkali washing process, condensation reflux and magnetic stirring are adopted, and the time is 2 to 48 h, preferably 5 to 24 h, and then hot suction filtration is carried out. Water washing is to wash several times with deionized water or ultrapure water. The liquid-solid mass ratio of water to the solid-phase material during water washing is 10:1 to 50:1, preferably 10:1 to 30:1; the acid solution used in the acid washing process can be one or several of hydrochloric acid, nitric acid, sulfuric acid, and acetic acid; the mass fraction of the acid solution is 0.5% to 20%, preferably 1% to 10%. The liquid-solid mass ratio of the acid solution to the solid material is 5:1 to 30:1, preferably 5:1 to 20:1.

[0043] Further, in the preparation method of the above high-rate supercapacitor carbon, the drying temperature in step (3) is 60 to 150 °C, preferably 60 to 120 °C; the drying time is 1 to 24 h, preferably 4 to 12 h.

[0044] The second aspect of the present invention provides a high-rate supercapacitor carbon obtained by the above preparation method.

[0045] Further, the pores of the provided high-rate supercapacitor carbon are concentrated in the range of 0.6 to 2 nm. The pore volume of the pores with a pore diameter of 0.6 to 2 nm in the pore structure is greater than 50% by volume, preferably not less than 60% by volume, and the ratio of the pore volume of the pores with a pore diameter of 1 to 2 nm to the pore volume of the pores with a pore diameter of 0.6 to 1 nm is 1 to 3, preferably 1.9 to 2.6.

[0046] Further, the pores of the provided high-rate supercapacitor carbon are concentrated in the range of 0.6 to 2 nm. The pores with a pore diameter of 0.6 to 2 nm, especially 1 to 2 nm, are beneficial to the effective infiltration of the electrolyte, shorten the ion and charge transfer distance, and the fast charge transfer speed significantly improves the rate performance, capacity, and long-cycle performance of the material.

[0047] Further, the specific surface area of the provided high-rate supercapacitor carbon is 1500 to 3000 m 2 / g, preferably 1800 to 2700 m 2 / g. A suitable specific surface area can better meet the requirements of the rate performance, capacity, and long-cycle performance of the supercapacitor.

[0048] Further, the Raman spectrogram of the provided high-rate supercapacitor carbon is at 800 - 2000 wavenumbers / cm-1 In the range, spectral peaks only appear at a wave velocity of 1300 - 1600 cm -1 In the range, and the spectral peak near 1350 cm -1 has a larger peak width and a smaller peak height than the spectral peak near 1580 cm -1 . Preferably, the spectral peak near 1300 wave numbers / cm -1 has a peak width ratio of 1:0.5 - 1.5 and a peak height ratio of 1:0.5 - 1 compared to the spectral peak near 1600 wave numbers / cm -1 .

[0049] Furthermore, the La value of the size of the aromatic sheet layer of the provided high-rate supercapacitor carbon is between 4.5 and 6 nm, preferably between 4.6 and 5.8 nm.

[0050] Furthermore, the La value of the size of the aromatic sheet layer of the provided high-rate supercapacitor carbon refers to the diameter of the aromatic layer sheet of the carbon graphite microcrystal. A larger La value is beneficial for shortening the ion and charge transport distances and accelerating the charge transport speed, thereby further ensuring that the capacitor has good rate performance, capacity, and long-cycle performance. In the present invention, the La value of the size of the aromatic sheet layer is obtained by using the X-ray diffraction result of the porous carbon material through the Scherrer formula L a = 0.89×0.15406 / (B (100) cosθ (100) ), where B (100) is the full-width at half-maximum corresponding to the (100) peak of the porous carbon material; θ (100) is the Bragg angle corresponding to the (100) peak.

[0051] The high-rate supercapacitor carbon provided by the present invention is suitable as supercapacitor carbon for supercapacitors because it has a large number of pores with a size of 0.6 - 2 nm, especially 1 - 2 nm, a relatively large specific surface area, and a high La value.

[0052] Compared with the prior art, the beneficial effects of the high-rate supercapacitor carbon and its preparation method provided by the present invention are embodied in the following aspects:

[0053] (1) In the preparation method of the high-rate supercapacitor carbon provided by the present invention, through organic intercalation, melt blending with asphalt, and high-speed shearing, the expansion of the kaolinite layer spacing and single-layer peeling are realized, providing two-dimensional nano-confined sheet-like small crystals for the preparation of supercapacitor carbon with excellent rate performance.

[0054] (2) In the preparation method of the high-rate supercapacitor carbon provided by the present invention, during the carbonization of asphalt, the organic-intercalated kaolinite hinders the relative movement of asphalt molecules and fixes the structural dimension of the material by means of the spatial partitioning effect of the sheet-like small crystals.

[0055] (3) In the preparation method of the high-rate supercapacitor carbon provided by the present invention, by controlling the raw material particle size and mixing method, and improving the carbonization-activation process, the small kaolin platelet crystals act as nanoscale confinement units during the activation process of petroleum coke and petroleum pitch, enabling the formation process of the supercapacitor carbon to proceed along the direction of two-dimensional sheets, and the prepared carbon material achieves a structure with long-range disorder and short-range order.

[0056] (4) The outer surface proportion of the petroleum-based composite carbon material with a nanoscale layered structure prepared by the method of the present invention is significantly increased, which is more conducive to the effective infiltration of the electrolyte, improves the effective utilization rate of the micropore specific surface area of the carbon material, and enhances the specific capacitance and energy density of the material.

[0057] (5) For the petroleum-based composite carbon material with a nanoscale layered structure prepared by the method of the present invention, due to the existence of the nano single-layer structure being conducive to the improvement of the activation degree, the aspect ratio of the pore structure of the obtained supercapacitor carbon is significantly reduced, and the rich short-range pore structure shortens the ion and charge transport distances. The fast charge transport speed significantly improves the rate performance and power density of the material.

[0058] (6) The petroleum-based composite carbon material with a nanoscale layered structure prepared by the present invention ensures that the supercapacitor carbon has good conductivity and fast charge transport performance, and significantly improves the overall capacitance performance of the petroleum-based carbon material. Description of the Drawings

[0059] Figure 1 It is the electron microscope photograph of the supercapacitor carbon obtained in Example 1 of the present invention.

[0060] Figure 2 It is the pore size distribution diagram of the supercapacitor carbon obtained in Example 1 of the present invention

[0061] Figure 3 It is the Raman spectrum diagram of the supercapacitor carbon obtained in Example 1 of the present invention. Detailed Embodiments

[0062] The following further illustrates the technical solutions and implementation effects of the present invention in combination with specific examples and comparative examples, but is not limited to the following examples.

[0063] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values and individual point values of each range, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0064] In this text, unless otherwise explicitly stated, percentages and percentage contents are based on mass.

[0065] In this text, the specific surface area and pore size distribution curve of the sample are obtained from the nitrogen adsorption - desorption curve on a Micromeritics ASAP 2020 adsorption instrument. The operating temperature is -196 °C (liquid nitrogen temperature). The sample is pre - dehydrated at 300 °C under nitrogen protection before testing. The specific surface area and pore size distribution are calculated by the BET method and the DFT method respectively. The proportion of pore structures in different pore size ranges is calculated according to the absolute value of pore volume. For example, for pores with a pore size distribution in the range of 0.6 - 1.0 nm, the pore volume V(0.6 - 1.0 nm) = V(1.0 nm) - V(0.6 nm), where V(1.0 nm) is the absolute value of the total pore volume corresponding to 1.0 nm on the adsorption curve, and so on. The proportion of pores in the range of 0.6 - 1.0 nm = V(0.6 - 1.0 nm) / Vtotal pore volume * 100%, and so on.

[0066] In this text, the value of the aromatic sheet size La of the carbon material is calculated from the Raman spectrum, La = 4.4I G / I D where I G and I D are the peak heights of the G peak and the D peak in the Raman spectrum of the sample respectively.

[0067] In this text, the electrochemical test method is as follows: Activated carbon, conductive agent acetylene black, and binder PVDF (polyvinylidene fluoride) are mixed evenly in a mass ratio of 8:1:1, coated on carbon - coated aluminum foil, and after drying and slicing, an organic - based button - type supercapacitor is assembled. The electrolyte is 1 mol / L tetraethylammonium tetrafluoroborate dissolved in propylene carbonate. Then, electrochemical performance tests and long - cycle performance tests are carried out on a Neware electrochemical tester (model BTS - 5V50mA).

[0068] Example 1

[0069] Weigh 30 g of kaolin, 15 g of dimethyl sulfoxide, and 6 g of water, place them in a beaker, ultrasonicate at 60 °C for 5 h, filter by suction, wash with ethanol, vacuum - dry at 60 °C for 6 h, grind, and sieve through a 200 - mesh sieve to obtain organically intercalated kaolin for standby.

[0070] Weigh 30 g of anthracene oil and 3 g of organically intercalated kaolin, ultrasonicate at 70 °C for 5 h, then add them to 15 g of asphalt in a molten state at 270 °C (softening point 260 °C), and shear the molten blend at a shear rate of 4000 r / min for 1 h using a high - speed shear machine. Recover anthracene oil by rotary evaporation. The resulting product is the first material.

[0071] Load the first material into a quartz ark, place it in a carbonization furnace, displace the air in the activation furnace with nitrogen at a flow rate of 500 mL / min for 20 min, then heat it to 600 °C at a rate of 5 °C / min under a nitrogen flow rate of 500 mL / min, keep it at a constant temperature for carbonization for 60 min, cool it to room temperature, and crush the carbonized product to a micron-level uniform mixture in an air flow crusher as the second material.

[0072] Mix the second material and 45 g of KOH evenly, load them into a corundum ark, place it in an activation furnace, heat it to 900 °C at a rate of 10 °C / min, keep it at a constant temperature for activation for 40 min, turn off the heating, take it out after cooling to room temperature, and it is the activated product. Transfer the activated product to a flask, add deionized water according to a liquid-solid ratio of 30:1, heat it to 100 °C and carry out condensation reflux, stir magnetically for 5 h, carry out hot suction filtration, then wash it with ultrapure water with a liquid-solid mass ratio of 40:1, and finally carry out suction filtration and washing with 5% dilute hydrochloric acid according to a solid-liquid mass ratio of 15:1, and then wash it with ultrapure water with a solid-liquid mass ratio of 40:1. The obtained filter cake is dried in a blast drying oven at 105 °C for 8 h to obtain porous carbon. Grind the porous carbon into a D50 of 6 - 10 μm, and pass it through a magnetic separator to remove excess metal ions to obtain pitch-based supercapacitor carbon.

[0073] The specific surface area of the obtained supercapacitor carbon is 2623 m 2 / g, the total proportion of pores less than 0.6 nm and pores greater than 2.0 nm is 35%, the pores with a size of 1.0 - 2.0 nm are 2.5 times the proportion of micropores with a size of 0.6 - 1.0 nm, and the size of the aromatic lamella is 4.8 nm.

[0074] After electrochemical testing, when the current density is 1 A / g, the mass specific capacitance of the organic device is 47.52 F / g. When the current density increases to 15 A / g, the mass specific capacitance of the organic device is 43.34 F / g, and the specific capacitance retention rate is 91.2%. It is a supercapacitor carbon with excellent rate performance.

[0075] Example 2

[0076] Weigh 10 g of kaolin, 10 g of dimethyl sulfoxide, and 5 g of ethanol, place them in a beaker, ultrasonicate at 80 °C for 8 h, carry out suction filtration, wash with ethanol, dry in vacuum at 90 °C for 4 h, grind, and sieve through a 200-mesh sieve to obtain organically intercalated kaolin for standby.

[0077] Weigh 20 g of diesel and 1 g of organically intercalated kaolin, ultrasonicate at 120 °C for 10 h, then add them to 30 g of mesophase pitch (softening point is 170 °C) in a molten state at 200 °C, shear the molten blend at a shear rate of 5000 r / min for 0.5 h using a high-speed shear machine, recover diesel by rotary evaporation, and the obtained product is the first material.

[0078] Load the first material into a quartz ark, place it in a carbonization furnace, displace the air in the activation furnace with nitrogen at a flow rate of 500 mL / min for 20 min, then heat it to 300 °C at a rate of 15 °C / min under a nitrogen flow rate of 500 mL / min, keep it at a constant temperature for carbonization for 300 min, cool it to room temperature, and crush the carbonization product in a jet mill to a micron-level homogeneous mixture as the second material.

[0079] Mix the second material and 24 g of potassium carbonate evenly, load them into a corundum ark, place it in an activation furnace, heat it to 700 °C at a rate of 5 °C / min, keep it at a constant temperature for activation for 120 min, turn off the heating, take it out after cooling to room temperature, and it is the activation product. Transfer the activation product to a flask, add deionized water according to a liquid-solid ratio of 10:1, heat it to 100 °C and condense and reflux, stir magnetically for 6 h, perform hot filtration, then wash it with ultrapure water with a liquid-solid mass ratio of 20:1, finally filter and wash it with 1% dilute hydrochloric acid according to a solid-liquid mass ratio of 30:1, and then wash it with ultrapure water with a liquid-solid mass ratio of 20:1. The obtained filter cake is dried in a blast drying oven at 120 °C for 4 h to obtain porous carbon. Grind the porous carbon into a D50 of 6 - 10 μm, and pass it through a magnetic separator to remove excess metal ions to obtain pitch-based supercapacitor carbon.

[0080] The specific surface area of the obtained supercapacitor carbon is 522 m 2 / g, the total proportion of pores <0.6 nm and >2.0 nm is 16%, the pores of 1.0 - 2.0 nm are 1.6 times the proportion of micropores of 0.6 - 1.0 nm, and the size of the aromatic lamella is 5.6 nm.

[0081] After electrochemical testing, when the current density is 1 A / g, the mass specific capacitance of the organic device is 12.62 F / g. When the current density increases to 15 A / g, the mass specific capacitance of the organic device is 5.39 F / g, and the specific capacitance retention rate is 42.7%.

[0082] Example 4

[0083] Weigh 15 g of kaolin, 3 g of dimethyl sulfoxide, and 5 g of water and place them in a beaker, ultrasonicate for 6 h at 70 °C, perform suction filtration, wash with ethanol, dry in vacuum at 70 °C for 8 h, grind, and sieve through a 200-mesh sieve to obtain organically intercalated kaolin for standby.

[0084] Weigh 44 g of benzene and 4 g of organically intercalated kaolin, ultrasonicate at 80 °C for 9 h, then add it to 16 g of pitch (softening point is 190 °C) in a molten state at 210 °C, shear the molten blend at a shear rate of 8000 r / min for 0.5 h using a high-speed shearer, recover benzene by rotary evaporation, and the obtained product is the first material.

[0085] Load the first material into a quartz ark, place it in a carbonization furnace. After replacing the air in the activation furnace with nitrogen at a flow rate of 500 mL / min for 20 min, heat it to 400 °C at a rate of 10 °C / min under a nitrogen flow rate of 500 mL / min, keep it at a constant temperature for carbonization for 120 min, cool it to room temperature. The carbonization product is pulverized to the micron level and uniformly mixed in a jet mill and used as the second material.

[0086] Mix the second material and 16 g of potassium hydroxide evenly, load them into a corundum ark, place it in an activation furnace, heat it to 850 °C at a rate of 2 °C / min, keep it at a constant temperature for activation for 90 min, turn off the heating, take it out after cooling to room temperature, and it is the activation product. Transfer the activation product to a flask, add deionized water according to a liquid-solid ratio of 15:1, heat it to 90 °C and carry out condensation reflux, stir magnetically for 8 h, perform hot suction filtration, then wash it with ultrapure water with a liquid-solid mass ratio of 25:1, and finally carry out suction filtration and washing with 6% dilute hydrochloric acid according to a solid-liquid mass ratio of 15:1, and then wash it with ultrapure water with a solid-liquid mass ratio of 20:1. The obtained filter cake is dried in a forced-air drying oven at 115 °C for 8 h to obtain porous carbon. Grind the porous carbon into a D50 of 6 - 10 μm, and pass it through a magnetic separator to remove excess metal ions to obtain pitch-based supercapacitor carbon.

[0087] The specific surface area of the obtained supercapacitor carbon is 907 m 2 / g, the total proportion of pores <0.6 nm and pores >2.0 nm is 28%, the pores of 1.0 - 2.0 nm are 1.7 times the proportion of micropores of 0.6 - 1.0 nm, and the size of the aromatic lamella is 5.3 nm.

[0088] After electrochemical testing, at a current density of 1 A / g, the mass specific capacitance of the organic device is 19.81 F / g. When the current density increases to 15 A / g, the mass specific capacitance of the organic device is 15.14 F / g, and the specific capacitance retention rate is 76.4%.

[0089] Comparative Example 1

[0090] Weigh 17 g of pitch (softening point 220 °C) and load it into a quartz ark, place it in a carbonization furnace. After replacing the air in the activation furnace with nitrogen at a flow rate of 500 mL / min for 20 min, heat it to 380 °C at a rate of 8 °C / min under a nitrogen flow rate of 500 mL / min, keep it at a constant temperature for carbonization for 120 min, cool it to room temperature. The carbonization product is pulverized to the micron level and uniformly mixed in a jet mill and used as the second material.

[0091] The second material and 42.5 g of potassium hydroxide were uniformly mixed, loaded into a corundum ark, placed in an activation furnace, heated to 900 °C at a rate of 6 °C / min, activated at a constant temperature for 60 min, the heating was turned off, and after cooling to room temperature, it was taken out as the activated product. It was washed with ultrapure water with a liquid-solid mass ratio of 30:1, and finally filtered and washed with 5% dilute hydrochloric acid according to a solid-liquid mass ratio of 20:1, and then washed with ultrapure water with a solid-liquid mass ratio of 30:1. The obtained filter cake was dried in a blast drying oven at 120 °C for 10 h to obtain porous carbon. The porous carbon was ball-milled and pulverized to a D50 of 6 - 10 μm, and the excess metal ions were removed by a magnetic separator to obtain pitch-based supercapacitor carbon.

[0092] The specific surface area of the obtained supercapacitor carbon was 1728 m 2 / g. The total proportion of pores <0.6 nm and pores >2.0 nm was 34%. The pores with a size of 1.0 - 2.0 nm were 2.7 times the proportion of micropores with a size of 0.6 - 1.0 nm, and the size of the aromatic lamella was 4.4 nm.

[0093] After electrochemical testing, at a current density of 1 A / g, the mass specific capacitance of the organic device was 28.46 F / g. When the current density increased to 15 A / g, the mass specific capacitance of the organic device was 20.27 F / g, and the specific capacitance retention rate was 71.2%.

[0094] Comparative Example 2

[0095] Weigh 20 g of kaolin, 12 g of dimethyl sulfoxide, and 6 g of water and place them in a beaker. Ultrasonic for 7 h at 65 °C, filter by suction, wash with ethanol, vacuum dry at 65 °C for 7 h, grind, and sieve through a 200-mesh sieve to obtain organically intercalated kaolin for standby.

[0096] Weigh 22 g of toluene and 2 g of organically intercalated kaolin, ultrasonic for 8 h at 75 °C, then add them to 20 g of pitch (softening point: 200 °C) in a molten state at 230 °C, and shear the molten blend at a shear rate of 5000 r / min for 1 h using a high-speed shear machine. Toluene was recovered by rotary evaporation, and the obtained product was the first material.

[0097] Mix the first material and 52 g of potassium hydroxide evenly, load them into a corundum ark, place it in an activation furnace, heat it to 750 °C at a rate of 10 °C / min, keep it at a constant temperature for activation for 90 min, turn off the heating, take it out after cooling to room temperature, and it is the activated product. Transfer the activated product to a flask, add deionized water according to a liquid-solid ratio of 30:1, heat it to 100 °C and carry out condensation reflux, stir magnetically for 5 h, perform hot filtration, then wash it with ultrapure water with a liquid-solid mass ratio of 30:1, and finally carry out suction filtration and washing with 5% dilute hydrochloric acid according to a solid-liquid mass ratio of 15:1, and then wash it with ultrapure water with a solid-liquid mass ratio of 35:1. The obtained filter cake is dried in a forced-air drying oven at 115 °C for 10 h to obtain porous carbon. Grind the porous carbon into a ball mill to a D50 of 6 - 10 μm, and pass it through a magnetic separator to remove excess metal ions to obtain pitch-based supercapacitor carbon.

[0098] The specific surface area of the obtained supercapacitor carbon is 1958 m 2 / g. The total proportion of pores less than 0.6 nm and pores greater than 2.0 nm is 36%. The pores with a size of 1.0 - 2.0 nm are 2.9 times the proportion of micropores with a size of 0.6 - 1.0 nm, and the size of the aromatic lamellae is 4.2 nm.

[0099] After electrochemical testing, when the current density is 1 A / g, the mass specific capacitance of the organic device is 32.83 F / g. When the current density increases to 15 A / g, the mass specific capacitance of the organic device is 25.69 F / g, and the specific capacitance retention rate is 78.3%.

[0100] Comparative Example 3

[0101] Weigh 70 g of anthracene oil and 10 g of kaolin, ultrasonicate them at 90 °C for 10 h, then add them to 25 g of mesophase pitch (softening point is 215 °C) in a molten state at 300 °C, and shear the molten blend at a shear rate of 5000 r / min for 2 h using a high-speed shear machine. Recover the anthracene oil by rotary evaporation, and the obtained product is the first material.

[0102] Load the first material into a quartz ark, place it in a carbonization furnace, displace the air in the activation furnace with nitrogen at a flow rate of 500 mL / min for 20 min, then heat it to 550 °C at a rate of 10 °C / min under a nitrogen flow rate of 500 mL / min, keep it at a constant temperature for carbonization for 90 min, and cool it to room temperature. The carbonized product is crushed to a micron level and evenly mixed in an air flow crusher as the second material.

[0103] The second material and 50 g of potassium hydroxide are uniformly mixed, loaded into a corundum ark, placed in an activation furnace, heated to 900 °C at a rate of 10 °C / min, isothermally activated for 20 min, the heating is turned off, and it is taken out after cooling to room temperature to obtain the activated product. The activated product is transferred to a flask, deionized water is added according to a liquid-solid ratio of 40:1, heated to 90 °C and condensed and refluxed, magnetically stirred for 8 h, hot filtered, and then washed with ultrapure water with a liquid-solid mass ratio of 30:1. Finally, it is filtered and washed with 5% dilute hydrochloric acid according to a solid-liquid mass ratio of 20:1, and then washed with ultrapure water with a solid-liquid mass ratio of 40:1. The obtained filter cake is dried in a blast drying oven at 120 °C for 6 h to obtain porous carbon. The porous carbon is ball milled and pulverized to a D50 of 6 - 10 μm, and excess metal ions are removed by a magnetic separator to obtain pitch-based supercapacitor carbon.

[0104] The specific surface area of the obtained supercapacitor carbon is 1468 m 2 / g. The total proportion of pores <0.6 nm and pores >2.0 nm is 33%. The pores with a size of 1.0 - 2.0 nm are 2.6 times the proportion of micropores with a size of 0.6 - 1.0 nm, and the size of the aromatic lamella is 4.5 nm.

[0105] After electrochemical testing, at a current density of 1 A / g, the mass specific capacitance of the organic device is 30.58 F / g. When the current density increases to 15 A / g, the mass specific capacitance of the organic device is 22.50 F / g, and the specific capacitance retention rate is 73.6%.

[0106] Comparative Example 4

[0107] Weigh 12.5 g of kaolin, 5 g of dimethyl sulfoxide, and 2.5 g of water and place them in a beaker. Ultrasonic for 9 h at 60 °C, filter by suction, wash with ethanol, vacuum dry at 60 °C for 8 h, grind, and sieve through a 200-mesh sieve to obtain organically intercalated kaolin for standby.

[0108] Weigh 1.5 g of organically intercalated kaolin and add it to 15 g of pitch (softening point: 210 °C) in a molten state at 260 °C. Use a high-speed shearer to shear the molten blend at a shear rate of 7000 r / min for 2 h, recover toluene by rotary evaporation, and the obtained product is the first material.

[0109] Load the first material into a quartz ark, place it in a carbonization furnace, displace the air in the activation furnace with nitrogen at a flow rate of 500 mL / min for 20 min, and then heat to 450 °C at a rate of 10 °C / min under a nitrogen flow rate of 500 mL / min, isothermally carbonize for 150 min, cool to room temperature, and the carbonized product is pulverized to a micron level and uniformly mixed in a gas flow crusher to obtain the second material.

[0110] Mix the second material and 45 g of potassium hydroxide evenly, load them into a corundum ark, place it in an activation furnace, heat it to 850 °C at a rate of 10 °C / min, keep it at a constant temperature for activation for 40 min, turn off the heating, take it out after cooling to room temperature, and obtain the activated product. Transfer the activated product to a flask, add deionized water according to a liquid-solid ratio of 40:1, heat it to 90 °C and carry out condensation reflux, stir magnetically for 8 h, perform hot filtration, then wash it with ultrapure water with a liquid-solid mass ratio of 20:1, and finally carry out suction filtration and washing with 5% dilute hydrochloric acid according to a solid-liquid mass ratio of 20:1, and then wash it with ultrapure water with a solid-liquid mass ratio of 30:1. The obtained filter cake is dried in a blast drying oven at 110 °C for 8 h to obtain porous carbon. Grind the porous carbon into a powder with a D50 of 6 - 10 μm, and pass it through a magnetic separator to remove excess metal ions to obtain pitch-based supercapacitor carbon.

[0111] The specific surface area of the obtained supercapacitor carbon is 2264 m 2 / g. The total proportion of pores less than 0.6 nm and pores greater than 2.0 nm is 46%. The pores with a size of 1.0 - 2.0 nm are 4.4 times the proportion of micropores with a size of 0.6 - 1.0 nm. The size of the aromatic lamella is 4.4 nm.

[0112] After electrochemical testing, when the current density is 1 A / g, the mass specific capacitance of the organic device is 39.57 F / g. When the current density increases to 15 A / g, the mass specific capacitance of the organic device is 28.84 F / g, and the specific capacitance retention rate is 72.9%.

Claims

1. A method for preparing a high-rate supercapacitor carbon, comprising the following steps: (1) Organic kaolin is obtained by organic intercalation treatment of kaolin; (2) mixing the organic kaolin from step (1) and asphalt uniformly under contact conditions, and then carbonizing the mixture; (3) The carbonized material from step (2) is mixed with alkali for activation treatment, and then washed and dried to obtain supercapacitor carbon.

2. The method for preparing high-rate supercapacitor carbon according to claim 1, characterized in that: The process of organic intercalation treatment in step (1) is to uniformly mix kaolin, organic intercalation agent and solvent for intercalation treatment, and then separate, wash and dry to obtain organic kaolin.

3. The method for preparing high-rate supercapacitor carbon according to claim 2, characterized in that: The organic intercalant is a strongly polar organic solvent, selected from one or more of dimethyl sulfoxide, tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, methyl silicone oil, alkyl quaternary ammonium salts with alkyl carbon numbers of 8-18, organic quaternary ammonium salts with hydroxyl or benzyl groups, acrylamide, silane coupling agents, and quaternary phosphonium salts, preferably one or more of dimethyl sulfoxide, octadecyl quaternary ammonium salts, and disoctadecylbenzyl quaternary ammonium salts.

4. The method for preparing high-rate supercapacitor carbon according to claim 2, characterized in that: The mass ratio of kaolin to the organic intercalant is 0.5:1 to 5:1, preferably 1:1 to 3:

1.

5. The method for preparing high-rate supercapacitor carbon according to claim 2, characterized in that: The solvent is water and / or an organic solvent. The organic solvent is one or more of ethanol, acetone, propanol, benzene and chloroform. The solvent is preferably one or more of water and ethanol.

6. The method for preparing high-rate supercapacitor carbon according to claim 2, characterized in that: The mass ratio of kaolin to solvent is 10:1 to 1:1, preferably 8:1 to 2:

1.

7. The method for preparing high-rate supercapacitor carbon according to claim 2, characterized in that: The intercalation treatment temperature is 20 to 100°C, preferably 40 to 90°C.

8. The method for preparing high-rate supercapacitor carbon according to claim 2, characterized in that: The drying temperature is 40-100° C., preferably 40-90° C.; after drying, organic kaolin is obtained.

9. The method for preparing high-rate supercapacitor carbon according to claim 1, characterized in that: The organic kaolin in step (2) is uniformly mixed with a hydrocarbon-containing solvent before being mixed with asphalt. The hydrocarbon-containing solvent is one or more of anthracene oil, gasoline, diesel, kerosene, toluene and benzene.

10. The method for preparing high-rate supercapacitor carbon according to claim 9, characterized in that: The mass ratio of the organic kaolin to the hydrocarbon-containing solvent is 1:30 to 1:1, preferably 1:20 to 3:

1.

11. The method for preparing high-rate supercapacitor carbon according to claim 9, characterized in that: In step (2), the temperature at which the organic kaolin and the hydrocarbon-containing solvent are mixed is 40 to 200° C., preferably 60 to 150° C.

12. The method for preparing high-rate supercapacitor carbon according to claim 1, characterized in that: The asphalt in step (2) is one or more of petroleum asphalt and coal asphalt, preferably petroleum asphalt, and more preferably mesophase asphalt.

13. The method for preparing high-rate supercapacitor carbon according to claim 1, characterized in that: The softening point of the asphalt in step (2) is 80 to 350°C, preferably 100 to 300°C.

14. The method for preparing high-rate supercapacitor carbon according to claim 1, characterized in that: In step (2), the mass ratio of asphalt to organic kaolin is 100:1 to 1:1, preferably 50:1 to 3:

1.

15. The method for preparing high-rate supercapacitor carbon according to claim 1, characterized in that: The mixing temperature after adding asphalt in step (2) is 50 to 250°C, preferably 80 to 300°C.

16. The method for preparing high-rate supercapacitor carbon according to claim 1, characterized in that: The carbonization treatment and activation treatment are carried out under the condition of inert atmosphere.

17. The method for preparing high-rate supercapacitor carbon according to claim 1, characterized in that: The carbonization treatment temperature in step (2) is 200-650°C, preferably 300-600°C.

18. The method for preparing high-rate supercapacitor carbon according to claim 1, characterized in that: After the carbonization treatment in step (2) is completed, the obtained solid material is crushed to a particle size of 10 to 100 μm, preferably 10 to 30 μm.

19. The method for preparing high-rate supercapacitor carbon according to claim 1, characterized in that: The base in step (3) is an inorganic base, which is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, potassium bicarbonate, sodium bicarbonate, calcium hydroxide, and magnesium hydroxide, preferably one or more of sodium hydroxide, potassium hydroxide, and potassium carbonate.

20. The method for preparing high-rate supercapacitor carbon according to claim 1, characterized in that: The activation treatment conditions in step (3) are as follows: the activation temperature is 600-1000°C, preferably 700-900°C.

21. The method for preparing high-rate supercapacitor carbon according to claim 1, characterized in that: The weight ratio of the asphalt in step (2) to the alkali in step (3) is 1:0.2 to 1:10, preferably 1:0.8 to 1:

3.

22. The method for preparing high-rate supercapacitor carbon according to claim 1, characterized in that: The washing in step (3) includes three steps of washing: alkali washing, water washing and acid washing.

23. A high-rate supercapacitor carbon obtained by the preparation method according to any one of claims 1 to 22.

24. The high-rate supercapacitor carbon according to claim 23, characterized in that: The pores of the high-rate supercapacitor carbon are concentrated in the range of 0.6 to 2.0 nm, the pore volume of pores with a pore diameter of 0.6 to 2.0 nm in the pore structure is greater than 50% by volume, preferably not less than 60% by volume, and the ratio of the pore volume of pores with a pore diameter of 1 to 2 nm to the pore volume of pores with a pore diameter of 0.6 to 1 nm is 1 to 3, preferably 1.9 to 2.

6.

25. The high rate supercapacitor carbon according to claim 23 or 24, characterized in that: The size La of the aromatic sheet of the high-rate supercapacitor carbon is between 4.5 and 6 nm, preferably between 4.6 and 5.8 nm.

26. The high rate supercapacitor carbon according to claim 23 or 24, characterized in that: The specific surface area of ​​high-rate supercapacitor carbon is 1500~3000m 2 / g, preferably 1800~2700 m 2 / g.

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