Layered structure super capacitor carbon and preparation method thereof

Abstract

The invention discloses super capacitor carbon with a layered structure and a preparation method thereof, and the preparation method comprises the following steps: (1) under a mixing condition, uniformly mixing asphalt and manganese dioxide, and then carrying out carbonization treatment in an inert atmosphere to obtain a first material; and (2) activating the first material and an activating agent in an inert atmosphere, and then washing and drying to obtain the supercapacitor carbon with a layered structure. The invention also provides the super capacitor carbon obtained by the preparation method. The invention provides super capacitor carbon with a layered structure and a preparation method thereof. The capacitor carbon which is large in specific surface area, reasonable in pore size distribution, high in ion transmission rate and excellent in rate capability is obtained.

Description

Technical Field

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

[0002] A supercapacitor is a power-type electrochemical energy storage device that stores energy by polarizing an electrolyte, and it stores energy by using the electric double layer on the electrode / electrolyte interface or the two-dimensional / quasi-two-dimensional Faraday reaction (polarized electrolyte) that occurs. A supercapacitor mainly consists of an electrode, an electrolyte, a separator, and a casing; compared with traditional chemical power sources (such as lead-carbon batteries, lithium batteries, etc.), it has the advantages of short charging time (in seconds), rapid response (in milliseconds), long service life (can be charged millions of times repeatedly), high energy conversion efficiency (large-current energy cycle efficiency ≥ 90%), high power density (300 W / kg - 5000 W / kg), good temperature characteristics (-45°C to +80°C), high safety factor (no active metals inside), environmental protection and no pollution, etc.

[0003] The electrode material of a supercapacitor is the key active material of the supercapacitor, and the activated carbon material is the most widely used and most economical electrode material. The electrode material has become a key factor affecting the performance and production cost of supercapacitors. Therefore, it can be said that almost all research on supercapacitors is carried out around the electrode material. As the most critical activated carbon electrode material for supercapacitors, extremely harsh requirements are imposed on its electrochemical performance, and its macro and micro structures need to be scientifically designed and regulated to continuously explore the performance potential.

[0004] Carbon materials such as activated carbon, graphene, carbon nanotubes, and carbon aerogels are widely used in the construction of supercapacitor electrode materials. In Patent CN 106115694 A, graphene oxide and pitch coke are directly subjected to high-temperature coking reduction and activation 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.

[0005] 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 prepares a nitrogen-doped carbon nanotube supercapacitor. Utilizing the characteristics of the structurally uniform and stable carbon nanotubes with good conductivity, the capacitance performance of the composite material is improved.

[0006] Patent CN 105185599A prepares a layered carbon composite material, including a porous carbon layer / graphene layer / porous carbon layer. Utilizing the characteristic that graphene is the material with the smallest resistivity currently discovered to provide more conductive points and conductive paths for ion conduction, the apparent conductivity of the composite material is improved. However, its porous carbon layer is carbonized by a hydrothermal synthesis method using a biomass raw material as a precursor. This method not only has a low product yield but is also not applicable to the preparation process of petroleum-based carbon materials. Summary of the Invention

[0007] Aiming at the above problems existing in the prior art, the object of the present invention is to provide a layered structure supercapacitor carbon and its preparation method 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 layered structure supercapacitor carbon, including the following steps:

[0009] (1) Under mixing conditions, asphalt and manganese dioxide are mixed evenly, and then carbonization treatment is carried out under an inert atmosphere to obtain a first material;

[0010] (2) Under activation conditions, the first material and an activator are subjected to activation treatment under an inert atmosphere, and then the layered structure supercapacitor carbon is obtained through washing and drying.

[0011] Further, in the above preparation method of the supercapacitor carbon, as a specific implementation manner, the crystal form of manganese dioxide in step (1) is δ-MnO 2 , the morphology is lamellar, the lamellar thickness of manganese dioxide is 5 - 100 nm, preferably 10 - 50 nm; the lamellar size of manganese dioxide is (20 - 50)×(200 - 500) nm.

[0012] Further, in the above preparation method of the supercapacitor carbon, as a specific implementation manner, the manganese dioxide in step (1) can be synthesized by a hydrothermal synthesis method.

[0013] Further, in the above method for preparing supercapacitor carbon, as a specific embodiment, the specific process of the manganese dioxide synthesis method in step (1) is as follows: A manganese-containing compound and an acid solution are mixed, and then a hydrothermal crystallization reaction is carried out. The reaction product is washed and dried to obtain manganese dioxide.

[0014] Further, in the above method for preparing supercapacitor carbon, as a specific embodiment, the manganese-containing compound can be selected from one or more of potassium permanganate, manganese chloride, manganese sulfate, potassium manganate, and manganese nitrate, and potassium permanganate is preferred.

[0015] Further, in the above method for preparing supercapacitor carbon, as a specific embodiment, the acid is an organic acid and / or an inorganic acid. The organic acid can be selected from one or more of acetic acid, citric acid, malic acid, tartaric acid, oxalic acid, and succinic acid, and acetic acid is preferred for the organic acid; the inorganic acid can be selected from one or more of hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid, and hydrochloric acid is preferred for the inorganic acid.

[0016] Further, in the above method for preparing supercapacitor carbon, as a specific embodiment, the concentration of the acid solution is 0.01 - 0.4 mol / L, preferably 0.01 - 0.2 mol / L.

[0017] Further, in the above method for preparing supercapacitor carbon, as a specific embodiment, the mass ratio of the acid solute to the manganese-containing compound is 0.1:1 - 2:1, preferably 0.3:1 - 1.5:1.

[0018] Further, in the above method for preparing supercapacitor carbon, as a specific embodiment, the temperature of the hydrothermal crystallization reaction is 100 - 200 °C, preferably 100 - 150 °C; the crystallization time is 40 min - 180 min, preferably 40 min - 120 min.

[0019] Further, in the above method for preparing supercapacitor carbon, as a specific embodiment, the washing includes water washing and anhydrous ethanol washing, and the two are alternately carried out for several times; when washing with water, the liquid-solid mass ratio of water to the solid-phase material is 5:1 - 20:1, preferably 10:1 - 20:1, and when washing with anhydrous ethanol, the liquid-solid mass ratio of anhydrous ethanol to the solid-phase material is 5:1 - 20:1, preferably 5:1 - 10:1.

[0020] Further, in the above method for preparing supercapacitor carbon, as a specific embodiment, the drying temperature is 60 - 150 °C, preferably 60 - 120 °C; the drying time is 1 - 24 h, preferably 4 - 12 h.

[0021] Further, in the above method for preparing supercapacitor carbon, as a specific embodiment, the pitch in step (1) is one or more of petroleum pitch and coal pitch, preferably petroleum pitch; the softening point of the pitch is 80 - 350 °C, preferably 100 - 300 °C.

[0022] Further, in the above method for preparing supercapacitor carbon, as a specific embodiment, the weight ratio of pitch to manganese dioxide is 20:1 - 2:1, preferably 10:1 - 3:1.

[0023] Further, in the above method for preparing supercapacitor carbon, as a specific embodiment, petroleum coke can be introduced in step (1), the particle size of the petroleum coke is 10 - 500 μm, preferably 20 - 100 μm; the volatile content in the petroleum coke is 5 wt% - 20 wt%. The petroleum coke can be selected from one or more of sponge coke and needle coke.

[0024] Further, in the above method for preparing supercapacitor carbon, as a specific embodiment, the weight ratio of pitch to petroleum coke is 20:1 - 1:1, preferably 10:1 - 2:1.

[0025] Further, in the above method for preparing supercapacitor carbon, as a specific embodiment, the mixing in step (1) can be carried out by any of the existing methods that can achieve uniform mixing of materials, specifically, it can be carried out by means such as air flow pulverization, mechanical mixing and pulverization, shearing, ball milling, etc.

[0026] Further, in the above method for preparing supercapacitor carbon, as a specific embodiment, the inert atmosphere in step (1) and step (2) can be one or more of nitrogen, helium, neon, argon, krypton, xenon, preferably nitrogen. Specifically, generally, the gas in the device is fully replaced with an inert atmosphere to ensure that there is no oxygen in the device.

[0027] Further, in the above method for preparing supercapacitor carbon, as a specific embodiment, the first material obtained in step (1) is preferably subjected to a crushing treatment, and generally, the particle size of the solid first material after crushing is 10 - 100 μm, preferably 10 - 30 μm.

[0028] Further, in the above method for preparing supercapacitor carbon, as a specific embodiment, the carbonization temperature in step (1) is 80 - 350 °C, preferably 100 - 300 °C; further control the heating rate to be 1 - 20 °C / min, preferably 5 - 15 °C / min.

[0029] Further, in the above preparation method of the supercapacitor carbon, as a specific embodiment, the carbonization treatment time in step (1) is 20 to 300 min, preferably 60 to 300 min.

[0030] Further, in the above preparation method of the supercapacitor carbon, as a specific embodiment, the activator in step (2) is one or a mixture of two or more of hydroxides and carbonates of Group IA metals and / or Group IIA metals. Further, the activator can be selected from one or several of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, potassium bicarbonate, sodium bicarbonate, calcium hydroxide, and magnesium hydroxide, preferably one or several of sodium hydroxide, potassium hydroxide, and potassium carbonate. Further preferably, the activator is a granular solid with a particle size of 10 to 300 μm.

[0031] Further, in the above preparation method of the supercapacitor carbon, as a specific embodiment, the activation conditions in step (2) are as follows: the activation temperature is 600 to 1000 °C, preferably 700 to 900 °C; further, the heating rate of activation is 1 to 10 °C / min, preferably 2 to 8 °C / min; the activation time is 20 to 180 min, preferably 20 to 120 min.

[0032] Further, in the above preparation method of the supercapacitor carbon, as a specific embodiment, the weight ratio of the first material to the activator in step (2) is 1:0.2 to 1:10, preferably 1:1 to 1:3.

[0033] Further, in the above preparation method of the supercapacitor carbon, as a specific embodiment, the washing in step (2) includes one-time water washing, acid washing, and secondary water washing operations. The main purpose is to remove alkaline substances and the like generated by the reaction through water washing, and expose the rich pore structure formed during the activation process. Generally, water washing is carried out by washing with deionized water or ultrapure water for several times. 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. Manganese dioxide in the product is removed by acid washing. The acid solution used in the acid washing process is concentrated hydrochloric acid with a mass fraction of 36% to 38%. The specific process of the acid washing is to heat and reflux with the acid solution at 40 to 80 °C, preferably 60 to 80 °C, for 1 to 6 h, preferably 2 to 4 h, and then the separated filter cake is washed with water for the second time. 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 separation can be carried out by suction filtration or other methods.

[0034] Further, in the above preparation method of the supercapacitor carbon, as a specific embodiment, the drying temperature in step (2) is 60 to 150 °C, preferably 60 to 120 °C; the drying time is 1 to 24 h, preferably 4 to 12 h.

[0035] The second aspect of the present invention provides a layered structure supercapacitor carbon obtained by the above preparation method.

[0036] Further, as a specific embodiment, the pore channels of the layered structure supercapacitor carbon are concentrated in the range of 0.6 - 2 nm. The pore volume of the pores with a pore diameter of 0.6 - 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 - 2 nm to the pore volume of the pores with a pore diameter of 0.6 - 1 nm is 1 - 3, preferably 1.9 - 2.6.

[0037] Further, as a specific embodiment, the pore channels of the layered structure supercapacitor carbon are concentrated in the range of 0.6 - 2 nm. The pores with a pore diameter of 0.6 - 2 nm, especially 1 - 2 nm, are beneficial to the effective infiltration of the electrolyte, shortening the ion and charge transport distance. The fast charge transport speed significantly improves the rate performance, capacity and long - cycle performance of the material.

[0038] Further, as a specific embodiment, the specific surface area of the layered structure supercapacitor carbon is 1500 - 3000 m 2 / g, preferably 1800 - 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.

[0039] In the present invention, the specific surface area and pore distribution curve are measured by the method obtained from the nitrogen adsorption - desorption curve on a Micromeritics ASAP 2020 type adsorption instrument.

[0040] The Raman spectrum of the layered structure supercapacitor carbon provided by the present invention shows peaks only in the range of 1300 - 1600 cm -1 -1 within the range of 800 - 2000 cm -1 -1, and the peak near 1350 cm -1 -1 has a larger peak width and a smaller peak height than the peak near 1580 cm -1 -1. Preferably, the ratio of the peak width of the peak near 1300 cm -1 -1 to the peak width of the peak near 1600 cm -1 -1 is 1:0.5 - 1.5, and the ratio of the peak height is 1:0.5 - 1.

[0041] Further, as a specific embodiment, the size La value of the aromatic sheet layer of the layered structure supercapacitor carbon is between 4.5 - 6 nm, preferably between 4.6 - 5.8 nm.

[0042] The La value, which represents the size of the aromatic sheets in the layered-structured supercapacitor carbon, refers to the diameter of the aromatic layers of carbon graphite microcrystals. 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 aromatic sheet size is calculated using the X-ray diffraction results 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.

[0043] The porous carbon material provided by the present invention is suitable as supercapacitor carbon for supercapacitors because it has a large number of pores with diameters of 0.6 - 2 nm, especially 1 - 2 nm, a large specific surface area, and a high La value.

[0044] Compared with the prior art, the beneficial effects of the layered-structured supercapacitor carbon and its preparation method provided by the present invention are reflected in the following aspects:

[0045] (1) The supercapacitor carbon provided by the present invention has a special nano-scale two-dimensional sheet-like structure and abundant short-range through-holes, ensuring the effective infiltration of the electrolyte and fast charge transport performance, and significantly improving the overall capacitance performance of the carbon material.

[0046] (2) In the preparation method of the supercapacitor carbon of the present invention, through the control and improvement of the raw material particle size and process method, the sheet-like manganese dioxide acts as a nano-scale confinement unit during the activation process of petroleum coke and pitch, ensuring that the formation process of the supercapacitor carbon proceeds along the direction of the two-dimensional sheet, and the prepared carbon material has a structure with long-range disorder and short-range order. In particular, by precisely controlling the hydrothermal synthesis conditions to achieve precise control of the crystal form and morphology of manganese dioxide, nano-sheet-like manganese dioxide that meets the requirements is obtained, providing the possibility of nano-confinement for the preparation of supercapacitor carbon with excellent electrochemical properties.

[0047] (3) In the preparation method of the supercapacitor carbon of the present invention, due to the existence of the nano-sheet-like structure, the outer surface ratio of the carbon material is significantly increased, which is more conducive to the effective infiltration of the electrolyte, improves the effective utilization rate of the microporous specific surface area of the carbon material, and enhances the specific capacitance and energy density of the material.

[0048] (4) In the preparation method of the supercapacitor carbon of the present invention, due to the existence of the nanosheet-like structure, it is beneficial to improve the activation degree. The aspect ratio of the pore structure of the obtained supercapacitor carbon is significantly reduced. The abundant short-range pore structure shortens the ion and charge transport distances, and the fast charge transport speed significantly improves the rate performance and power density of the material. Description of the Drawings

[0049] Figure 1 It is the electron microscope image of the supercapacitor carbon prepared in Example 1 of the present invention.

[0050] Figure 2 It is the pore size distribution diagram of the supercapacitor carbon prepared in Example 2 of the present invention.

[0051] Figure 3 It is the Raman spectrum diagram of the supercapacitor carbon prepared in Example 3 of the present invention. Detailed Embodiments

[0052] The technical solutions and implementation technical effects of the present invention will be further described below in conjunction with specific examples and comparative examples, but are not limited to the following examples.

[0053] 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 of each range and individual point values, 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.

[0054] In this article, unless otherwise specifically stated, percentages and percentage contents are by mass.

[0055] In this article, 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 type 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.

[0056] In this article, the electron microscope is tested with a JEOL field emission scanning electron microscope JEM7500M; the Raman is tested with an HR-800 type Raman spectrometer produced by HORIBA JobinYvon of France.

[0057] In this article, the properties of the petroleum coke raw materials used in the examples and comparative examples are as follows: the sulfur content is 4.15 wt%, the volatile matter is 15.79 wt%, and the ash content is 0.79 wt%. The needle coke used is self-made in the laboratory, with a true density of 1.83 g / cm 3 , the volatile matter content is 8.1 wt%, the sulfur content is 0.2 wt%, the moisture content is 0.5 wt%, and it has a wide-area streamline fibrous structure.

[0058] In this article, the softening point of the selected petroleum pitch is 215 °C, and the toluene-insoluble content is 56 wt%; the softening point of the anisotropic pitch is 270 °C, the toluene-insoluble is 74.1 wt%, and the mesophase content is 100%; the softening point of the isotropic pitch is 265 °C, the toluene-insoluble is 77.3 wt%, and the mesophase content is 0.

[0059] In this article, the electrochemical test method is as follows: Activated carbon, conductive agent acetylene black, and binder PVDF (polyvinylidene fluoride) are mixed evenly according to a mass ratio of 8:1:1, coated on carbon-coated aluminum foil, assembled into an organic button-type supercapacitor after drying and slicing, where 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).

[0060] Example 1

[0061] Prepare 60 mL of a CH 3 COOH solution with a molar concentration of 0.4 mol / L, weigh 1.0 g of KMnO 4 powder and add it to the acetic acid solution. After magnetic stirring at room temperature until completely dissolved, transfer it to a 100 mL polytetrafluoroethylene inner liner, and then place it in a high-pressure reaction kettle and seal it. Transfer the high-pressure reaction kettle to a 100 °C oven for constant-temperature crystallization for 2 h, then turn off the oven and let it cool naturally to room temperature. Wash and filter the purified product, wash it alternately with deionized water and absolute ethanol 3 times, and dry the obtained filter cake in the oven at 80 °C for 10 h to obtain 0.55 g of manganese dioxide nanosheets. React multiple times under the same conditions to prepare a total of 3.3 g of manganese dioxide nanosheets for standby.

[0062] Weigh 10 g of petroleum coke, 5 g of petroleum pitch, and 3 g of the manganese dioxide nanosheets prepared above, put them into a quartz boat, place it in a carbonization furnace, use nitrogen to displace the air in the activation furnace at a flow rate of 500 mL / min for 20 min, then at a rate of 5 °C / min, heat up to 300 °C at a nitrogen flow rate of 500 mL / min, keep it at a constant temperature for carbonization for 100 min, cool to room temperature, and crush them together to micron-level uniform mixing in an air flow crusher as the first material.

[0063] Mix the first material and 45 g of KOH evenly, load them into a corundum ark, place it in an activation furnace, heat it up to 900 °C at a rate of 10 °C / min, keep it at a constant temperature for activation for 20 min, turn off the heating, take it out after cooling to room temperature, and it is the activated product. Wash it with ultrapure water with a liquid-solid mass ratio of 40:1, then add it to 150 mL of concentrated hydrochloric acid, heat it under reflux at 65 °C for half an hour, filter it by suction, and then wash it with ultrapure water with a liquid-solid mass ratio of 50:1 until it is neutral. 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 ball mill to a D50 of 8 - 10 μm, and remove the excess metal ions through a magnetic separator to obtain petroleum-based supercapacitor carbon.

[0064] The specific surface area of the obtained supercapacitor carbon is 2465 m 2 / g, the total proportion of pores <0.6 nm and pores >2.0 nm is 38%, the pores with a size of 1.0 - 2.0 nm are 2.4 times the proportion of micropores with a size of 0.6 - 1.0 nm, and the size of the aromatic lamellae is 4.7 nm.

[0065] After electrochemical testing, when the current density is 1 A / g, the mass specific capacitance of the organic device is 44.9 F / g. When the current density increases to 15 A / g, the mass specific capacitance of the organic device is 39.3 F / g, and the specific capacitance retention rate is 87.5%. It is a supercapacitor carbon with excellent rate performance. The electron microscope image of the supercapacitor carbon is shown in the appendix Figure 1 .

[0066] Example 2

[0067] Prepare 60 mL of hydrochloric acid solution with a molar concentration of 0.2 mol / L, weigh 0.29 g of MnCl 2 powder and add it to the hydrochloric acid solution. Stir magnetically at room temperature until it is completely dissolved, then transfer it to a 100 mL polytetrafluoroethylene inner liner, and then load it into a high-pressure reaction kettle and seal it. Transfer the high-pressure reaction kettle to an oven at 140 °C and keep it at a constant temperature for crystallization for 40 min, then turn off the oven and let it cool naturally to room temperature. Wash and filter the purified product, wash it alternately with deionized water and absolute ethanol 3 times, and dry the obtained filter cake in the oven at 80 °C for 6 h to obtain 0.2 g of manganese dioxide nanosheets. Prepare it 5 times under the same conditions to obtain 1 g of manganese dioxide nanosheets for standby.

[0068] Weigh 10 g of petroleum coke, 1 g of isotropic pitch, and 1 g of the prepared manganese dioxide nanosheets, load them into a quartz ark, place it in an activation furnace, use nitrogen to displace the air in the activation furnace at a flow rate of 500 mL / min for 20 min, and then at a rate of 500 mL / min of nitrogen flow rate, heat it up to 350 °C at a rate of 15 °C / min, keep it at a constant temperature for carbonization for 100 min, and after cooling to room temperature, crush them together to a micron level and mix them evenly in a jet mill to obtain the first material.

[0069] Put the first material and 22 g of KOH into a corundum ark, place it in an activation furnace, heat it up to 800 °C at a rate of 8 °C / min, keep it at a constant temperature for activation for 80 min, turn off the heating, take it out after cooling to room temperature, and it is the activated product. Wash it with ultrapure water with a liquid-solid mass ratio of 40:1, then add it to 150 mL of concentrated hydrochloric acid with a concentration of 36% - 38%, heat it under reflux at 65 °C for half an hour, filter it by suction, and then wash it with ultrapure water with a liquid-solid mass ratio of 30:1 until it is neutral. 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 ball mill until D50 is 8 - 10 μm, and remove the excess metal ions through a magnetic separator to obtain petroleum-based supercapacitor carbon.

[0070] The specific surface area of the obtained supercapacitor carbon is 1982 m 2 / g, the total proportion of pores <0.6 nm and pores >2.0 nm is 35%, the pores of 1.0 - 2.0 nm are 2.5 times the proportion of micropores of 0.6 - 1.0 nm, and the size of the aromatic lamella is 5.1 nm.

[0071] After electrochemical testing, when the current density is 1 A / g, the mass specific capacitance of the organic device is 34.3 F / g. When the current density increases to 15 A / g, the mass specific capacitance of the organic device is 28.1 F / g, and the specific capacitance retention rate is 81.9%, with excellent rate performance.

[0072] Example 3

[0073] Prepare 60 mL of acetic acid solution with a molar concentration of 0.05 mol / L, weigh 0.6 g of KMnO 4 powder and add it to the acetic acid solution. Stir magnetically at room temperature until it is completely dissolved, then transfer it to a 100 mL polytetrafluoroethylene inner liner, and then put it into a high-pressure reaction kettle and seal it. Transfer the high-pressure reaction kettle to an oven at 110 °C for constant-temperature crystallization for 70 min, then turn off the oven and let it cool naturally to room temperature. Wash and filter the purified product, wash it alternately with deionized water and absolute ethanol 3 times, and dry the obtained filter cake in the oven at 100 °C for 6 h to obtain 0.33 g of manganese dioxide nanosheets. Repeat the preparation 10 times under the same conditions to obtain 3.3 g of manganese dioxide nanosheets for standby.

[0074] Weigh 10 g of petroleum coke, 5 g of anisotropic pitch, and 3.3 g of the prepared manganese dioxide nanosheets, put them into a quartz ark, place it in an activation furnace, use nitrogen to displace the air in the activation furnace at a flow rate of 500 mL / min for 20 min, then at a rate of 500 mL / min of nitrogen flow rate, heat it up to 290 °C at a rate of 10 °C / min, keep it at a constant temperature for carbonization for 180 min, and after cooling to room temperature, crush them together to micron-level uniform mixing in a gas flow crusher as the first material.

[0075] Put the first material and 37.5 g of KOH into a corundum ark, place it in an activation furnace, heat it up to 850 °C at a rate of 5 °C / min, keep it at a constant temperature for 60 min, turn off the heating, take it out after cooling to room temperature, and it is the activated product. Wash it with ultrapure water with a liquid-solid mass ratio of 40:1, then add it to 150 mL of concentrated hydrochloric acid with a concentration of 36% - 38%, heat it under reflux at 65 °C for half an hour, filter it by suction, and then wash it with ultrapure water with a liquid-solid mass ratio of 50:1 until it is neutral. The obtained filter cake is dried in a forced-air drying oven at 105 °C for 10 h to obtain porous carbon. Grind the porous carbon into a D50 of 8 - 10 μm, and remove the excess metal ions through a magnetic separator to obtain petroleum-based supercapacitor carbon.

[0076] The specific surface area of the obtained supercapacitor carbon is 2221 m 2 / g, the total proportion of pores less than 0.6 nm and pores greater than 2.0 nm is 39%, the pores with a size of 1.0 - 2.0 nm are 2.3 times the proportion of micropores with a size of 0.6 - 1.0 nm, and the size of the aromatic lamella is 4.6 nm.

[0077] After electrochemical testing, when the current density is 1 A / g, the mass specific capacitance of the organic device is 42.2 F / g. When the current density increases to 15 A / g, the mass specific capacitance of the organic device is 35.9 F / g, and the specific capacitance retention rate is 85.1%, with excellent rate performance.

[0078] Example 4

[0079] Prepare 60 mL of CH 3 COOH solution with a molar concentration of 0.36 mol / L, weigh 1.0 g of KMnO 4 powder and add it to the acetic acid solution. Stir magnetically at room temperature until it is completely dissolved, then transfer it to a 100 mL polytetrafluoroethylene inner liner, and then put it into a high-pressure reaction kettle and seal it. Transfer the high-pressure reaction kettle to an oven at 100 °C and keep it at a constant temperature for 1.5 h, then turn off the oven and let it cool naturally to room temperature. Wash and filter the purified product, wash it alternately with deionized water and absolute ethanol 3 times, and dry the obtained filter cake in the oven at 80 °C for 10 h to obtain 0.55 g of manganese dioxide nanosheets. React multiple times under the same conditions to prepare a total of 3.3 g of manganese dioxide nanosheets for standby.

[0080] Weigh 12 g of petroleum pitch and 3 g of the manganese dioxide nanosheets prepared above, put them into a quartz ark, place it in a carbonization furnace, use nitrogen to displace the air in the activation furnace at a flow rate of 500 mL / min for 20 min, and then at a rate of 5 °C / min, heat it up to 330 °C at a nitrogen flow rate of 500 mL / min, keep it at a constant temperature for 90 min, cool it to room temperature, and crush them together in a jet mill to a micron-level homogeneous mixture as the first material.

[0081] The first material and 34 g of KOH were uniformly mixed, loaded into a corundum ark, placed in an activation furnace, heated to 850 °C at a rate of 5 °C / min, isothermally activated for 30 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 40:1, then added to 150 mL of concentrated hydrochloric acid, heated under reflux at 65 °C for half an hour, filtered by suction, and then washed with ultrapure water with a liquid-solid mass ratio of 50:1 until neutral. The obtained filter cake was dried in a forced-air drying oven at 105 °C for 8 h to obtain porous carbon. The porous carbon was ball-milled and pulverized to a D50 of 8 - 10 μm, and the excess metal ions were removed by a magnetic separator to obtain petroleum-based supercapacitor carbon.

[0082] The specific surface area of the obtained supercapacitor carbon was 2165 m 2 / g, the total proportion of pores <0.6 nm and >2.0 nm was 38%, the pores of 1.0 - 2.0 nm were 2.5 times the proportion of micropores of 0.6 - 1.0 nm, and the size of the aromatic lamella was 4.6 nm.

[0083] After electrochemical testing, at a current density of 1 A / g, the mass specific capacitance of the organic device was 41.6 F / g. When the current density increased to 15 A / g, the mass specific capacitance of the organic device was 34.7 F / g, and the specific capacitance retention rate was 83.4%, which was a supercapacitor carbon with excellent rate performance.

[0084] Example 5

[0085] Prepare 60 mL of a CH 3 COOH solution with a molar concentration of 0.41 mol / L, weigh 1.0 g of KMnO 4 powder and add it to the acetic acid solution. After magnetic stirring at room temperature until completely dissolved, transfer it to a 100 mL polytetrafluoroethylene inner liner, and then load it into a high-pressure reaction kettle and seal it. The high-pressure reaction kettle was transferred to an oven at 100 °C for isothermal crystallization for 1.8 h, then the oven was turned off and it was naturally cooled to room temperature. The purified product was washed and filtered by suction, and washed alternately with deionized water and absolute ethanol 3 times. The obtained filter cake was dried in the oven at 80 °C for 10 h to obtain 0.55 g of manganese dioxide nanosheets. Under the same conditions, 3.3 g of manganese dioxide nanosheets were prepared by reacting multiple times and reserved.

[0086] Weigh 9 g of anisotropic mesophase pitch and 3 g of the manganese dioxide nanosheets prepared above, load them into a quartz ark, place it in a carbonization furnace, use nitrogen to displace the air in the activation furnace at a flow rate of 500 mL / min for 20 min, and then at a rate of 500 mL / min of nitrogen flow rate, heat it to 360 °C at a rate of 5 °C / min, isothermally carbonize for 120 min, cool to room temperature, and co-crush them to micron-level uniform mixture in a jet mill as the first material.

[0087] The first material and 18 g of KOH are uniformly mixed, loaded into a corundum ark, placed in an activation furnace, heated to 800 °C at a rate of 5 °C / min, activated at a constant temperature for 60 min, the heating is turned off, and after cooling to room temperature, it is taken out as the activated product. It is washed with ultrapure water with a liquid-solid mass ratio of 40:1, then added to 150 mL of concentrated hydrochloric acid, heated under reflux at 65 °C for half an hour, filtered by suction, and then washed with ultrapure water with a liquid-solid mass ratio of 50:1 until neutral. The obtained filter cake is dried in a forced-air drying oven at 105 °C for 8 h to obtain porous carbon. The porous carbon is ball-milled and pulverized to a D50 of 8 - 10 μm, and the excess metal ions are removed by a magnetic separator to obtain petroleum-based supercapacitor carbon.

[0088] The specific surface area of the obtained supercapacitor carbon is 1892 m 2 / g, the total proportion of pores <0.6 nm and >2.0 nm is 28%, the pores of 1.0 - 2.0 nm are 1.9 times the proportion of micropores of 0.6 - 1.0 nm, and the size of the aromatic lamellae is 5.3 nm.

[0089] After electrochemical testing, at a current density of 1 A / g, the mass specific capacitance of the organic device is 32.2 F / g. When the current density increases to 15 A / g, the mass specific capacitance of the organic device is 25.6 F / g, and the specific capacitance retention rate is 79.5%. It is a supercapacitor carbon with excellent rate performance.

[0090] Example 6

[0091] Prepare 60 mL of a CH 3 COOH solution with a molar concentration of 0.2 mol / L, weigh 0.29 g of MnCl 2 powder and add it to the hydrochloric acid solution. After magnetic stirring at room temperature until completely dissolved, transfer it to a 100 mL polytetrafluoroethylene inner liner, and then load it into a high-pressure reaction kettle and seal it. The high-pressure reaction kettle is transferred to an oven at 140 °C for constant-temperature crystallization for 40 min, then the oven is turned off, and it is naturally cooled to room temperature. The purified product is washed and filtered by suction, and washed alternately with deionized water and absolute ethanol 3 times. The obtained filter cake is dried in the oven at 80 °C for 6 h to obtain 0.2 g of manganese dioxide nanosheets. Prepared 5 times under the same conditions to obtain 1 g of manganese dioxide nanosheets for standby.

[0092] Weigh 1 g of petroleum coke, 10 g of isotropic pitch, and 1 g of the prepared manganese dioxide nanosheets, load them into a quartz ark, place them in an activation furnace, and use nitrogen to displace the air in the activation furnace at a flow rate of 500 mL / min for 20 min. Then, at a rate of 15 °C / min, heat it to 320 °C at a nitrogen flow rate of 500 mL / min, carbonize it at a constant temperature for 100 min, and after cooling to room temperature, co-crush it to the micron level and uniformly mix it in a gas flow crusher to obtain the first material.

[0093] Put the first material and 25 g of KOH into a corundum ark, place it in an activation furnace, heat it up to 850 °C at a rate of 8 °C / min, keep it at a constant temperature for activation for 60 min, turn off the heating, take it out after cooling to room temperature, and it is the activated product. Wash it with ultrapure water with a liquid-solid mass ratio of 40:1, then add it to 150 mL of concentrated hydrochloric acid with a concentration of 36% - 38%, heat it under reflux at 65 °C for half an hour, carry out suction filtration, and then wash it with ultrapure water with a liquid-solid mass ratio of 30:1 until it is neutral. 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 8 - 10 μm, and remove the excess metal ions through a magnetic separator to obtain petroleum-based supercapacitor carbon.

[0094] The specific surface area of the obtained supercapacitor carbon is 2076 m 2 / g. The total proportion of pores with <0.6 nm and pores with >2.0 nm is 36%. The pores with 1.0 - 2.0 nm are 2.2 times the proportion of micropores with 0.6 - 1.0 nm. The size of the aromatic lamella is 4.9 nm.

[0095] After electrochemical testing, when the current density is 1 A / g, the mass specific capacitance of the organic device is 36.1 F / g. When the current density increases to 15 A / g, the mass specific capacitance of the organic device is 28.4 F / g, and the specific capacitance retention rate is 78.7%.

[0096] Comparative Example 1

[0097] Weigh 10 g of petroleum coke and 5 g of petroleum pitch, put them into a quartz ark, place it in a carbonization furnace, use nitrogen to displace the air in the activation furnace at a flow rate of 500 mL / min for 20 min, then at a rate of 5 °C / min, heat it up to 300 °C under a nitrogen flow rate of 500 mL / min, keep it at a constant temperature for carbonization for 100 min, cool it to room temperature, and crush them together to a micron-level uniform mixture in an air flow crusher as the first material.

[0098] Mix the first material and 45 g of KOH evenly, put them into a corundum ark, place it in an activation furnace, heat it up to 900 °C at a rate of 10 °C / min, keep it at a constant temperature for activation for 20 min, turn off the heating, take it out after cooling to room temperature, and it is the activated product. Wash it with ultrapure water with a liquid-solid mass ratio of 40:1, then carry out suction filtration and washing with 5% dilute hydrochloric acid according to a liquid-solid mass ratio of 15:1 until it is neutral. 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 8 - 10 μm, and remove the excess metal ions through a magnetic separator to obtain petroleum-based supercapacitor carbon.

[0099] The specific surface area of the obtained supercapacitor carbon is 2268 m 2 / g, the total proportion of pores with a size of <0.6 nm and >2.0 nm is 48%, the pores with a size of 1.0 - 2.0 nm are 3.2 times the proportion of micropores with a size of 0.6 - 1.0 nm, and the size of the aromatic lamella is 4.4 nm.

[0100] After electrochemical testing, at a current density of 1 A / g, the mass specific capacitance of the organic device is 41.3 F / g. When the current density increases to 15 A / g, the mass specific capacitance of the organic device is 31.8 F / g, and the retention rate of the specific capacitance is 77.0%.

[0101] Comparative Example 2

[0102] Prepare 60 mL of a CH solution with a molar concentration of 0.4 mol / L 3 COOH solution, weigh 1.0 g of KMnO 4 powder and add it to the acetic acid solution. After magnetic stirring at room temperature until completely dissolved, transfer it to a 100 mL polytetrafluoroethylene inner liner, and then place it in a high-pressure reactor and seal it. Transfer the high-pressure reactor to an oven at 100 °C for constant-temperature crystallization for 2 h, then turn off the oven and let it cool naturally to room temperature. Wash and filter the purified product, wash it alternately with deionized water and absolute ethanol 3 times, and dry the obtained filter cake in the oven at 80 °C for 10 h to obtain 0.55 g of manganese dioxide nanosheets. A total of 3.3 g of manganese dioxide nanosheets were prepared using 6 high-pressure reactors under the same conditions and set aside.

[0103] Weigh 10 g of petroleum coke and 3.3 g of the prepared manganese dioxide nanosheets, place them in a quartz boat, put them into a carbonization furnace, use nitrogen to displace the air in the activation furnace at a flow rate of 500 mL / min for 20 min, then at a rate of 5 °C / min, heat up to 300 °C under a nitrogen flow rate of 500 mL / min, keep it at a constant temperature for carbonization for 100 min, cool to room temperature, and crush them together in a jet mill to a micron-level uniform mixture as the first material.

[0104] Mix the first material and 30 g of KOH evenly, place them in a corundum boat, put them into an activation furnace, heat up to 900 °C at a rate of 10 °C / min, keep it at a constant temperature for activation for 20 min, turn off the heating, take it out after cooling to room temperature, and it is the activated product. Wash it with ultrapure water with a liquid-solid mass ratio of 40:1, then add it to 150 mL of concentrated hydrochloric acid with a concentration of 36% - 38%, heat and reflux at 65 °C for half an hour, filter, and then wash it with ultrapure water with a liquid-solid mass ratio of 50:1 until neutral. Dry the obtained filter cake in a forced-air drying oven at 105 °C for 8 h to obtain porous carbon. Grind the porous carbon into a D50 of 8 - 10 μm, and remove the excess metal ions through a magnetic separator to obtain petroleum-based supercapacitor carbon.

[0105] The specific surface area of the obtained supercapacitor carbon is 2605 m 2 / g, the total proportion of pores with a size less than 0.6 nm and pores with a size greater than 2.0 nm is 43%. The pores with a size of 1.0 - 2.0 nm are 3.2 times the proportion of micropores with a size of 0.6 - 1.0 nm. The size of the aromatic lamella is 4.2 nm.

[0106] After electrochemical testing, when the current density is 1 A / g, the mass specific capacitance of the organic device is 46.1 F / g. When the current density increases to 15 A / g, the mass specific capacitance of the organic device is 36.2 F / g, and the retention rate of the specific capacitance is 78.5%.

[0107] Comparative Example 3

[0108] Prepare 60 mL of a CH 3 COOH solution with a molar concentration of 0.4 mol / L, weigh 1.0 g of KMnO 4 powder and add it to the acetic acid solution. Stir magnetically at room temperature until completely dissolved, then transfer it to a 100 mL polytetrafluoroethylene inner liner, and then place it in a high-pressure reaction kettle and seal it. Transfer the high-pressure reaction kettle to an oven at 100 °C for constant-temperature crystallization for 2 h, then turn off the oven and let it cool naturally to room temperature. Wash and filter the purified product, wash it alternately 3 times with deionized water and absolute ethanol, and dry the obtained filter cake in the oven at 80 °C for 10 h to obtain 0.55 g of manganese dioxide nanosheets. A total of 3.3 g of manganese dioxide nanosheets were prepared using 6 high-pressure reaction kettles under the same conditions for standby.

[0109] Weigh 10 g of petroleum pitch and 3.3 g of the prepared manganese dioxide nanosheets, place them in a quartz boat, put it into a carbonization furnace, use nitrogen to displace the air in the activation furnace at a flow rate of 500 mL / min for 20 min, then heat it to 300 °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 100 min, cool it to room temperature, and crush them together to a micron-level homogeneous mixture in an air flow crusher as the first material.

[0110] Mix the first material and 30 g of KOH evenly, place them in a corundum boat, put it into an activation furnace, heat it to 900 °C at a rate of 10 °C / min, keep it at a constant temperature for activation for 20 min, turn off the heating, take it out after cooling to room temperature, and it is the activated product. Wash it with ultrapure water with a liquid-solid mass ratio of 40:1, then add it to 150 mL of concentrated hydrochloric acid with a concentration of 36% - 38%, heat it under reflux at 65 °C for half an hour, filter it, and then wash it with ultrapure water with a liquid-solid mass ratio of 50:1 until neutral. Dry the obtained filter cake in a forced-air drying oven at 105 °C for 8 h to obtain porous carbon. Grind the porous carbon into a D50 of 8 - 10 μm, and remove the excess metal ions through a magnetic separator to obtain petroleum-based supercapacitor carbon.

[0111] The specific surface area of the obtained supercapacitor carbon is 1896 m 2 / g, the total proportion of pores with a size less than 0.6 nm and greater than 2.0 nm is 34%. The pores with a size between 1.0 and 2.0 nm are 2.4 times the proportion of micropores with a size between 0.6 and 1.0 nm. The size of the aromatic lamella is 5.0 nm.

[0112] After electrochemical testing, when the current density is 1 A / g, the mass specific capacitance of the organic device is 28.4 F / g. When the current density increases to 15 A / g, the mass specific capacitance of the organic device is 22.7 F / g, and the retention rate of the specific capacitance is 79.9%.

Claims

1. A method for preparing a layered supercapacitor carbon, comprising the following steps: (1) mixing asphalt and manganese dioxide under mixing conditions, and then carbonizing them under an inert atmosphere to obtain a first material; (2) Under activation conditions, the first material and the activator are activated in an inert atmosphere, and then washed and dried to obtain a layered supercapacitor carbon.

2. The method for preparing supercapacitor carbon according to claim 1, characterized in that: The manganese dioxide in step (1) has a crystalline form of δ-MnO2 and a lamellar morphology. The thickness of the manganese dioxide lamellar layer is 5 to 100 nm, preferably 10 to 50 nm. The size of the manganese dioxide lamellar layer is (20 to 50) × (200 to 500) nm.

3. The method for preparing supercapacitor carbon according to claim 1, characterized in that: The asphalt in step (1) is one or more of petroleum asphalt and coal asphalt, preferably petroleum asphalt; the softening point of the asphalt is 80-350°C, preferably 100-300°C.

4. The method for preparing supercapacitor carbon according to claim 1, characterized in that: The weight ratio of asphalt to manganese dioxide is 20:1 to 2:1, preferably 10:1 to 3:

1.

5. The method for preparing supercapacitor carbon according to claim 1, characterized in that: In step (1), petroleum coke is introduced, and the petroleum coke is selected from one or more of sponge coke and needle coke.

6. The method for preparing supercapacitor carbon according to claim 5, characterized in that: The particle size of the petroleum coke is 10 to 500 μm, preferably 20 to 100 μm; the volatile matter content in the petroleum coke is 5 wt% to 20 wt%.

7. The method for preparing supercapacitor carbon according to claim 5, characterized in that: The weight ratio of asphalt to petroleum coke is 20:1 to 1:1, preferably 10:1 to 2:

1.

8. The method for preparing supercapacitor carbon according to claim 1, characterized in that: The inert atmosphere in step (1) and step (2) is one or more of nitrogen, helium, neon, argon, krypton, and xenon, preferably nitrogen.

9. The method for preparing supercapacitor carbon according to claim 1, characterized in that: The first material obtained in step (1) is crushed, and the particle size of the first material after crushing is 10 to 100 μm, preferably 10 to 30 μm.

10. The method for preparing supercapacitor carbon according to claim 1, characterized in that: The carbonization treatment temperature in step (1) is 80 to 350°C, preferably 100 to 300°C.

11. The method for preparing supercapacitor carbon according to claim 1, characterized in that: The activator in step (2) is one or a mixture of two or more of the hydroxides and carbonates of Group IA metals and / or Group IIA metals.

12. The method for preparing supercapacitor carbon according to claim 1, characterized in that: The activator in step (2) is selected from 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.

13. The method for preparing supercapacitor carbon according to claim 1, characterized in that: The activation conditions in step (2) are as follows: the activation temperature is 600 to 1000°C, preferably 700 to 900°C.

14. The method for preparing supercapacitor carbon according to claim 1, characterized in that: The weight ratio of the first material to the activating agent in step (2) is 1:0.2 to 1:10, preferably 1:1 to 1:

3.

15. The method for preparing supercapacitor carbon according to claim 1, characterized in that: The washing in step (2) includes a water wash, an acid wash and a secondary water wash. The washing is performed several times with deionized water or ultrapure water. The acid solution used for the acid wash is concentrated hydrochloric acid with a mass fraction of 36% to 38%.

16. The method for preparing supercapacitor carbon according to claim 1, characterized in that: The drying temperature in step (2) is 60 to 150°C, preferably 60 to 120°C.

17. A layered supercapacitor carbon obtained by the preparation method according to any one of claims 1 to 16.

18. The layered supercapacitor carbon according to claim 17, characterized in that: The pores of the layered supercapacitor carbon are concentrated in the range of 0.6 to 2.0 nm, and the pore volume of pores with a pore diameter of 0.6 to 2.0 nm in the pore structure accounts for more than 50% of the total pore volume, preferably not less than 60%; 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.

19. The layered supercapacitor carbon according to claim 17, characterized in that: The size La of the aromatic sheets of the layered supercapacitor carbon is between 4.5 and 6 nm, preferably between 4.6 and 5.8 nm.

20. The layered supercapacitor carbon according to claim 17, characterized in that: The specific surface area of ​​layered supercapacitor carbon is 1500~3000m 2 / g, preferably 1800-2700 m 2 / g.

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