CN109786128B - Porous carbon/carbon nanotube composite material, preparation method thereof, electrode and supercapacitor - Google Patents
Porous carbon/carbon nanotube composite material, preparation method thereof, electrode and supercapacitor Download PDFInfo
- Publication number
- CN109786128B CN109786128B CN201910204832.8A CN201910204832A CN109786128B CN 109786128 B CN109786128 B CN 109786128B CN 201910204832 A CN201910204832 A CN 201910204832A CN 109786128 B CN109786128 B CN 109786128B
- Authority
- CN
- China
- Prior art keywords
- carbon
- porous carbon
- modified
- composite material
- modifier
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/13—Energy storage using capacitors
Abstract
The invention provides a porous carbon/carbon nanotube composite material, a preparation method thereof, an electrode and a supercapacitor. The method comprises the following steps: carrying out first modification treatment on the porous carbon so as to obtain modified porous carbon with negative charges; carrying out second modification treatment on the carbon nano tube so as to obtain a modified carbon nano tube with positive charges; and mixing the modified porous carbon and the modified carbon nanotube to obtain the porous carbon/carbon nanotube composite material. The method can enable the modified porous carbon and the modified carbon nano tube to be self-assembled through electrostatic interaction, the porous carbon and the carbon nano tube in the obtained composite material are uniform and stable in dispersion and low in internal resistance or good in conductivity, and the specific capacity and the cycling stability of the composite material can be obviously improved when the composite material is used for a super capacitor.
Description
Technical Field
The invention relates to the technical field of materials, in particular to a porous carbon/carbon nanotube composite material, a preparation method thereof, an electrode and a supercapacitor.
Background
The super capacitor is used as a novel energy storage device, and is one of electrochemical energy storage technologies with application prospects due to extremely high power density (500-10000W/kg), good cycle life (more than 50 ten thousand times) and extremely fast charge and discharge rate. However, the low energy density (5-10 Wh/kg) of the super capacitor greatly limits the application of the super capacitor. The energy density of a supercapacitor is closely related to the conductivity and specific surface area of its electrode material itself. Therefore, the development of electrode materials with high specific surface area and high conductivity is a research hotspot in the field of supercapacitors.
The active substance of the electrode material used by the conventional super capacitor is mainly activated carbon with high specific surface area, and because of low conductivity, a large amount of conductive agent needs to be added in the preparation process of the electrode, so that the quality of the electrode is increased, and the specific capacitance of the electrode material prepared by the method is greatly reduced. In addition, Carbon Nanotubes (CNTs) have become a very valuable electrode material for electric double layer capacitors because of their good electrical conductivity and chemical stability and unique one-dimensional electron conduction channels. Particularly, the CNT is used as an additive for preparing a carbon/carbon composite, and the fact that the CNT is doped into the activated carbon with high specific surface area is reported to effectively reduce the internal resistance and the charge-discharge rate of a super capacitor and obviously improve the cycle performance of an activated carbon electrode due to the high conductivity of the CNT.
However, in practical use, the carbon nanotubes need to be prepared into a dispersion with a certain concentration for subsequent processing, and in both aqueous and organic systems, the carbon nanotubes have low solubility or dispersity, mainly due to van der waals forces between the carbon nanotubes, resulting in the precipitation of the carbon nanotubes. In order to provide dispersibility of carbon nanotubes, carbon nanotubes can be modified, and currently, there are two methods for modifying carbon nanotubes: one is covalent bond and the other is non-covalent bond. The covalent bond mode is to treat the carbon nano tube by acid or introduce functional groups or polymers on the surface of the carbon nano tube; the non-covalent bond mode is usually to add a surfactant to realize the dispersion of the carbon nanotubes, but after the carbon nanotubes are directly mixed with the activated carbon, the introduction of surface functional groups or other molecular groups of the carbon nanotubes can greatly reduce the conductivity of the carbon nanotubes, so that the excellent conductivity of the carbon nanotubes can not be exerted, meanwhile, the carbon nanotubes and the activated carbon are simply and physically mixed, a good conductive channel can not be formed between the carbon nanotubes and the activated carbon, and self-agglomeration can occur in the slurry mixing process, so that a compact structure is not easily formed with the activated carbon.
Thus, the current supercapacitor electrode materials still need to be improved.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, an object of the present invention is to provide a porous carbon/carbon nanotube composite material which is uniform, stable, and has good electron conductivity, low internal resistance, or good electrical conductivity.
In one aspect of the invention, a method of preparing a porous carbon/carbon nanotube composite is provided. According to an embodiment of the invention, the method comprises: carrying out first modification treatment on the porous carbon so as to obtain modified porous carbon with negative charges; carrying out second modification treatment on the carbon nano tube so as to obtain a modified carbon nano tube with positive charges; and mixing the modified porous carbon and the modified carbon nanotube to obtain the porous carbon/carbon nanotube composite material. The inventor finds that the method can enable the modified porous carbon and the modified carbon nanotube to be assembled by self through electrostatic interaction, the porous carbon and the carbon nanotube in the obtained composite material are uniform and stable in dispersion and low in internal resistance or good in conductivity, and the specific capacity and the cycling stability of the composite material can be obviously improved when the composite material is used for a super capacitor.
According to an embodiment of the invention, the first modification treatment of the porous carbon comprises: mixing the porous carbon with a first modifier, and carrying out first solid-phase ball milling treatment on the obtained mixture, wherein the first modifier is negatively charged.
According to an embodiment of the present invention, the first modifier contains at least one of a carboxyl group and a hydroxyl group.
According to an embodiment of the present invention, the first modifier is at least one selected from the group consisting of carboxymethyl cellulose, a DNA strand, glucose, sucrose and lactic acid.
According to the embodiment of the invention, the rotation speed of the first solid phase ball milling treatment is 200-400 r/min, and the time is 1-10 h.
According to an embodiment of the invention, the porous carbon comprises at least one of activated carbon, graphene, graphite, soft carbon and hard carbon.
According to an embodiment of the invention, the mass ratio of the porous carbon to the first modifier is 4-80:1, preferably 20-40: 1.
According to an embodiment of the present invention, the second modification treatment of the carbon nanotubes includes: and mixing the carbon nano tube with a second modifier with positive charges, and carrying out second solid-phase ball milling treatment on the obtained mixture.
According to an embodiment of the present invention, the second modifier contains at least one of an amino group and a quaternary ammonium cation.
According to an embodiment of the invention, the second modifier is selected from at least one of polyaniline, polydiallyldimethylammonium chloride, and poly-p-vinylphenylmethylene- (5, 5-dimethylhydantoin) methyl-dimethyl.
According to the embodiment of the invention, the rotation speed of the second solid phase ball milling treatment is 200-400 r/min, and the time is 6-12 h.
According to an embodiment of the present invention, the mass ratio of the carbon nanotubes to the second modifier is 2-20:1, preferably 5-10: 1.
According to an embodiment of the present invention, mixing the modified porous carbon with the modified carbon nanotubes comprises: dispersing the modified porous carbon in a first solvent to obtain a first mixed solution; dispersing the modified carbon nano tube in a second solvent to obtain a second mixed solution; and adding the first mixed solution into the second mixed solution, centrifuging the obtained mixture, and drying the obtained precipitate to obtain the mixed raw material.
According to an embodiment of the invention, the pH of the second solvent is between 3 and 5.
According to an embodiment of the invention, said dispersing comprises sonication for a time of 1-2 h.
According to the embodiment of the invention, the modified activated carbon and the modified carbon nanotubes are mixed according to the mass ratio of the carbon nanotubes to the porous carbon of 1: 5-20.
According to an embodiment of the invention, the method further comprises: and carbonizing the porous carbon/carbon nanotube composite material.
According to the embodiment of the invention, the carbonization treatment is carried out by keeping the temperature for 0.5-5h under the conditions of inert atmosphere and 800 ℃.
According to the embodiment of the invention, the temperature rise speed is 2-10 ℃/min.
According to the embodiment of the invention, the heat preservation at the temperature of 500-800 ℃ for 0.5-5h is carried out by the following steps: heating to 350 ℃ at the speed of 2-10 ℃/min, preserving the heat for 20-40min, and then heating to 800 ℃ at the temperature of 400 ℃ for 0.5-1.5 h.
In another aspect of the invention, the invention provides a porous carbon/carbon nanotube composite. According to the embodiment of the invention, the porous carbon/carbon nanotube composite material is prepared by the method. The inventor finds that the porous carbon and the carbon nano tube in the composite material are uniformly and stably dispersed, so that the resistance is low and the conductivity is good.
In yet another aspect of the invention, an electrode is provided. According to an embodiment of the invention, the electrode comprises a porous carbon/carbon nanotube composite as described above. The inventor finds that the capacitor containing the electrode has higher specific capacity and greatly improves the cycling stability.
In yet another aspect of the present invention, a supercapacitor is provided. According to an embodiment of the invention, the supercapacitor comprises the aforementioned porous carbon/carbon nanotube composite material or the aforementioned electrode. The inventor finds that the super capacitor has higher specific capacity and greatly improves the cycling stability.
Compared with the prior art, the invention has at least the following beneficial effects:
1) the invention adopts a simple and effective solid-phase ball milling method to realize the surface modification of the porous carbon and the carbon nano tube, and the porous carbon and the carbon nano tube are self-assembled by electrostatic action due to the opposite charges on the surface, so that a uniform compound of the porous carbon and the carbon nano tube is finally obtained;
2) according to the invention, on the premise of not adding other conductive additives, the preparation of the capacitor material with low internal resistance is realized, as listed in Table 1, the internal resistance is greatly reduced along with the rise of the carbonization treatment temperature, and when the temperature exceeds 700 ℃, the internal resistance is reduced slowly, which indicates that high molecules are gradually decomposed to form amorphous carbon along with the rise of the temperature, and further the electron conduction effect between the carbon nano tube and the porous carbon is increased.
3) The high polymer material between the porous carbon and the carbon nano tube prepared by high-temperature calcination (namely carbonization treatment) is decomposed at high temperature, so that the conductivity of the obtained composite material is improved, and the high polymer material is obviously superior to the condition that the carbon nano tube is directly used as a conductive additive;
4) because the carbon nano tube and the porous carbon in the porous carbon/carbon nano tube composite material are uniformly and tightly compounded, the internal resistance of the capacitor adopting the composite material is greatly reduced, and the specific capacity and the cycling stability of the capacitor are also improved, the invention provides a feasible thought for the research and development of the capacitance carbon in the future.
5) The preparation of the composite material of the invention omits the addition of other conductive additives, thereby reducing the weight of the whole capacitor device in the actual production of the capacitor and further improving the energy density of the capacitor.
Drawings
Fig. 1 is a schematic flow chart of a method for preparing a porous carbon/carbon nanotube composite material according to an embodiment of the present invention.
Fig. 2 is a schematic flow chart of a method for preparing a porous carbon/carbon nanotube composite material according to another embodiment of the present invention.
FIG. 3 is a SEM photograph of the composite material prepared in example 5 of the present invention.
Detailed Description
The following describes embodiments of the present invention in detail. The following examples are illustrative only and are not to be construed as limiting the invention. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.
In one aspect of the invention, a method of preparing a porous carbon/carbon nanotube composite is provided. According to an embodiment of the invention, referring to fig. 1, the method comprises the steps of:
s100: the porous carbon is subjected to a first modification treatment to obtain a negatively charged modified porous carbon.
According to an embodiment of the present invention, in this step, the porous carbon and the first modifying agent having a negative charge may be mixed, and the resulting mixture may be subjected to a first solid-phase ball milling treatment to obtain the above-described modified porous carbon. Specifically, a planetary ball mill can be adopted, the ball milling medium can be zirconium beads, after the ball milling treatment is completed, a ball milling product can be dispersed in water and separated from the zirconium beads, then the obtained dispersion liquid is subjected to ultrasonic treatment for 30min-2h (such as 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min, 120min and the like), then the redundant first modifier is removed through vacuum filtration, a filter cake is collected, and then the filter cake is subjected to drying treatment (such as drying at 80 ℃ for 24h) to obtain the modified porous carbon. Therefore, the operation is simple and convenient, the modification effect is good, and the zeta potential of the modified porous carbon is obviously reduced.
According to the embodiment of the present invention, the rotation speed of the first solid phase ball milling treatment is 200-; the time can be 1-10h, specifically 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h and the like. Within the above rotation speed and time range, the porous carbon and the modifier can be sufficiently mixed and contacted, and if the rotation speed is too high, the structure of the porous carbon is influenced to a certain extent, and if the rotation speed is too low, the modification is insufficient.
According to an embodiment of the present invention, in order to obtain modified porous carbon having suitable electronegativity, the mass ratio of the porous carbon to the first modifier in this step may be 4-80:1, specifically, 4:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1, 55:1, 60:1, 65:1, 70:1, 75:1, 80:1, and so on. In some embodiments, the mass ratio of the porous carbon to the first modifier can be 20-40:1, such as 20:1, 21:1, 22:1, 23:1, 24:1, 25:1, 26:1, 27:1, 28:1, 29:1, 30:1, 31:1, 32:1, 33:1, 34:1, 35:1, 36:1, 37:1, 38:1, 39:1, 40:1, and the like. Within the range of the proportion, the balance between the dispersibility and the conductivity can be achieved, if the proportion is too high, the amorphous carbon in the finally obtained composite material is increased, and further the conductivity of the composite is reduced, and if the proportion is too low, the porous carbon is insufficiently modified, the uniformity of the dispersion is influenced, and further the composite with the carbon nano tube is influenced.
According to the embodiment of the present invention, the first modifying agent that can be used carries a negative charge, and specifically, the first modifying agent can carry a negatively charged functional group, for example, the first modifying agent can contain at least one of a carboxyl group and a hydroxyl group. Therefore, the modified porous carbon can carry negative charges, and a uniform composite material can be formed with the carbon nanotubes in the subsequent step.
According to some embodiments of the invention, the first modifier comprises at least one of carboxymethyl cellulose, a DNA strand, glucose, sucrose and lactic acid. Therefore, the material is wide in source, easy to obtain and suitable in electronegativity, so that the zeta potential of the modified porous carbon can be obviously reduced, and the uniform and stable composite material can be formed with the modified carbon nanotube in the subsequent steps.
According to the embodiment of the present invention, the specific kind of the porous carbon that can be used can be flexibly selected according to actual needs, and in some specific embodiments, the porous carbon includes at least one of activated carbon, graphene, graphite, soft carbon, and hard carbon. Therefore, the composite material has a large specific surface area and high conductivity, is beneficial to improving the uniformity, stability and electrical properties of the obtained composite material, and has the advantages of wide and easily-obtained material source and low cost.
According to a specific embodiment of the invention, in the step, carboxymethyl cellulose is adopted to modify activated carbon, specifically, a mixture of carboxymethyl cellulose and activated carbon is put into a planetary ball mill, zirconium beads are used as a ball milling medium, ball milling is carried out for 1-10 hours at a rotating speed of 300 revolutions per minute, then a ball milling product is dispersed into water, zirconium beads are separated, then the dispersion liquid is subjected to ultrasonic treatment for 30min-2 hours, then vacuum filtration is carried out to remove redundant carboxymethyl cellulose and collect a filter cake, and then the filter cake is dried for 24 hours at a temperature of 80 ℃ to obtain the modified activated carbon. The zeta potential of the activated carbon before and after modification is tested, and the result shows that the zeta potential of the activated carbon before modification is-7.56 mV, and the zeta potential of the activated carbon after modification is-48.6 mV, which indicates that the carboxymethyl cellulose has better modification effect on the activated carbon.
S200: and carrying out second modification treatment on the carbon nano tube so as to obtain the modified carbon nano tube with positive charges.
According to an embodiment of the present invention, in this step, the carbon nanotubes may be mixed with a second modifier having a positive charge, and the resulting mixture may be subjected to a second solid phase ball milling process to obtain modified carbon nanotubes. Specifically, a planetary ball mill can be adopted, the ball milling medium can be zirconium beads, after the ball milling treatment is completed, a ball milling product can be dispersed in water and separated from the zirconium beads, then the obtained dispersion liquid is subjected to ultrasonic treatment for 30min-2h (such as 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min, 120min and the like), then the redundant second modifier is removed through vacuum filtration, a filter cake is collected, and then the filter cake is subjected to drying treatment (such as drying at 80 ℃ for 24h) to obtain the modified carbon nanotube. Therefore, the operation is simple and convenient, the modification effect is good, and the zeta potential of the carbon nano tube after modification treatment is obviously increased.
According to the embodiment of the invention, the rotation speed of the second solid phase ball milling treatment is 200-; the time can be 6-12h, specifically 6h, 7h, 8h, 9h, 10h, 11h, 12h, and the like. Within the above rotation speed and time range, the carbon nanotubes and the second modifier can be sufficiently mixed and contacted, and if the carbon nanotubes are too high, the carbon nanotubes have a certain influence on the structure of the carbon nanotubes, and if the carbon nanotubes are too low, the carbon nanotubes are insufficiently modified.
According to an embodiment of the present invention, in order to obtain a modified carbon nanotube having suitable electropositivity, the mass ratio of the carbon nanotube to the second modifier in this step may be 2-20:1, specifically, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, and the like. In some embodiments, the mass ratio of the carbon nanotubes to the second modifier is 2-20:1, and the mass ratio may be 5-10: 1. Within the proportion range, the balance between the dispersibility and the conductivity can be achieved, if the proportion is too high, the amorphous carbon in the finally obtained composite material is increased, and further the conductivity of the composite material is reduced, and if the proportion is too low, the carbon nano tube is insufficiently modified, the uniformity of the dispersion is influenced, and further the composition with the porous carbon is influenced.
According to embodiments of the present invention, a second modifier may be used that carries a negative charge, and in particular, the first modifier may carry a positively charged functional group, for example, the second modifier may contain at least one of an amino group and a quaternary ammonium cation. Therefore, the modified carbon nano tube can carry positive charges, and can be self-assembled with the modified porous carbon through electrostatic interaction to form a uniform and stable composite material.
According to some specific embodiments of the invention, the second modifier comprises at least one of polyaniline, polydiallyldimethylammonium chloride, and poly-p-vinylphenylmethylene- (5, 5-dimethylhydantoin) methyl-dimethyl. Therefore, the material is wide in source and easy to obtain, has proper electropositivity, can obviously increase the zeta potential of the modified carbon nanotube, and is favorable for forming a uniform and stable composite material with the modified porous carbon.
According to an embodiment of the present invention, in this step, polyaniline is used to modify the carbon nanotubes, and polyaniline having an aromatic structure and the carbon nanotubes can be combined together through pi-pi interaction. Specifically, the mixture of polyaniline and carbon nanotubes is put into a planetary ball mill, zirconium beads are used as a ball milling medium, ball milling is carried out for 6-12h at the rotating speed of 300 r/min, then ball milling products are dispersed into an aqueous solution with the pH value of about 3 (specifically, the pH value of water can be adjusted by acid (such as at least one of dilute hydrochloric acid and dilute ammonium bicarbonate) or a buffer solution is adopted), the zirconium beads are separated, then the dispersion liquid is subjected to ultrasonic treatment for 30min-2h, then vacuum filtration is carried out to remove redundant polyaniline and collect filter cakes, and then the filter cakes are dried for 24h at the temperature of 80 ℃ to obtain the modified carbon nanotubes. The zeta potential of the carbon nano tube before and after modification in water with the pH value of about 3 is tested, and the result shows that the zeta potential of the carbon nano tube before modification is +3.2mV, and the zeta potential of the carbon nano tube after modification is +36.1mV, which indicates that polyaniline has better modification effect on the carbon nano tube.
S300: and mixing the modified porous carbon and the modified carbon nanotube to obtain the porous carbon/carbon nanotube composite material.
According to an embodiment of the present invention, mixing the modified porous carbon with the modified carbon nanotubes comprises: dispersing the modified porous carbon in a first solvent to obtain a first mixed solution; dispersing the modified carbon nano tube in a second solvent to obtain a second mixed solution; and mixing the first mixed solution and the second mixed solution, centrifuging the obtained mixture, and drying the obtained precipitate to obtain the mixed raw material. In the step, the modified porous carbon and the modified carbon nanotube are dispersed firstly, so that the modified porous carbon and the modified carbon nanotube are uniformly dispersed after being mixed, and the modified porous carbon and the modified carbon nanotube can be self-assembled into a uniform and stable composite material through electrostatic interaction in a specific mixing process.
According to the embodiment of the present invention, the specific manner of dispersing the modified porous carbon and the modified carbon nanotube is not particularly limited as long as it can be uniformly dispersed. In some embodiments, the modified porous carbon can be added to the first solvent for 1-2h (e.g., 60min, 70min, 80min, 90min, 100min, 110min, 120min, etc.), or the modified carbon nanotubes can be added to the second solvent for 1-2h (e.g., 60min, 70min, 80min, 90min, 100min, 110min, 120min, etc.). Therefore, the dispersion effect is good, the modified porous carbon and the modified carbon nano tube can not agglomerate, and the uniform and stable composite material can be obtained in the subsequent steps.
According to the embodiment of the invention, the first mixed solution and the second mixed solution are mixed, the first mixed solution can be uniformly dripped into the second mixed solution under the stirring condition (such as magnetic stirring), and after the dripping is completed, the stirring can be continued for 2-12h (such as 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h and the like). Therefore, the first mixed liquid and the second mixed liquid are mixed more uniformly, and the obtained composite material is more uniform and stable. After stirring, vacuum filtration can be carried out, filter cakes are collected and vacuum drying is carried out for 24 hours at the temperature of 70 ℃, and the porous carbon/carbon nanotube composite material is obtained. If necessary, the mixed raw material after vacuum drying may be subjected to a grinding and pulverization treatment to obtain a porous carbon/carbon nanotube composite material having a suitable particle diameter.
According to an embodiment of the present invention, the modified activated carbon may be mixed with the modified carbon nanotubes in a mass ratio of the carbon nanotubes to the porous carbon of 1:5 to 20 (e.g., 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, 1:20, etc.). Within the proportion range, the balance between the conductivity and the mass specific capacity of the composite material can be achieved, the proportion is too high, the carbon nanotube proportion is improved, the specific capacity of the composite material can be further reduced, the proportion is too low, the conductivity of the composite material is low, and other conductive agents still need to be added.
According to the embodiment of the present invention, the specific kinds of the first solvent and the second solvent are not particularly limited as long as the modified porous carbon or the modified carbon nanotube can be effectively dispersed. In some embodiments, the first solvent can be water and the second solvent can be water at a pH of 3 to 5 (e.g., 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, etc.). Therefore, the dispersion effect is better.
According to an embodiment of the present invention, referring to fig. 2, the method may further include the steps of:
s400: and carbonizing the porous carbon/carbon nanotube composite material.
According to the embodiment of the invention, the carbonization treatment is carried out by keeping the temperature for 0.5-5h under the conditions of inert atmosphere and 800 ℃. Specifically, the inert atmosphere includes, but is not limited to, nitrogen, etc., the temperature may be 400 ℃, 450 ℃, 500 ℃, 550 ℃, 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, etc., and the incubation time may be 0.5h, 1.0h, 1.5h, 2.0h, 2.5h, 3.0h, 3.5h, 4.0h, 4.5h, 5.0h, etc. Therefore, the first modifier and the second modifier can be carbonized and decomposed to form amorphous carbon, so that the electronic conduction effect between the carbon nanotube and the porous carbon can be enhanced, and tests prove that the temperature range and the time range can achieve better effects than other temperatures and times.
According to some embodiments of the present invention, the temperature ramp rate can be 2-10 deg.C/min (e.g., 2 deg.C/min, 3 deg.C/min, 4 deg.C/min, 5 deg.C/min, 6 deg.C/min, 7 deg.C/min, 8 deg.C/min, 9 deg.C/min, 10 deg.C/min, etc.). Therefore, the temperature rise speed range is easy to operate and implement, and tests prove that the temperature rise speed range can have better effect than other temperature rise speeds.
In some embodiments, the porous carbon/carbon nanotube composite material may be heated to 350 ℃ for 20-40min in an inert atmosphere at a heating rate of 2-10 ℃/min, and then heated to 800 ℃ for 0.5-1.5h in 400-. Therefore, the components such as the first modifier, the second modifier and the like can be better carbonized, a conductive channel is formed between the carbon nanotube and the porous carbon, and the electrical property of the composite material is further improved.
The inventor finds that the method can enable the modified porous carbon and the modified carbon nanotube to be assembled by self through electrostatic interaction, so that the porous carbon and the carbon nanotube in the obtained composite material are uniformly and stably dispersed, and through carbonization treatment, substances introduced by the modification treatment can be carbonized to be decomposed to form conductive amorphous carbon, and further the ion conduction effect between the carbon nanotube and the porous carbon is enhanced.
In another aspect of the invention, the invention provides a porous carbon/carbon nanotube composite. According to the embodiment of the invention, the porous carbon/carbon nanotube composite material is prepared by the method. The inventor finds that the porous carbon and the carbon nano tube in the composite material are uniformly and stably dispersed, and meanwhile, no modifier exists between the porous carbon and the carbon nano tube, and the porous carbon and the carbon nano tube can be connected through the porous carbon, so that the composite material is low in resistance and good in conductivity, and when the composite material is used for a super capacitor, the specific capacity and the cycling stability of the super capacitor can be obviously improved, and the internal resistance of the super capacitor is.
In yet another aspect of the invention, an electrode is provided. According to an embodiment of the invention, the electrode comprises a porous carbon/carbon nanotube composite as described above. The inventor finds that the electrode has good conductivity and higher specific capacity or greatly improves the cycling stability.
According to an embodiment of the present invention, the above-described composite material serves as an active material, and besides, the electrode sheet includes the structure and components of a conventional electrode sheet. In some embodiments, the porous carbon/carbon nanotube composite material and the binder (e.g., PVDF) may be mixed and dispersed in a solvent (e.g., N-methylpyrrolidone, NMP) at a mass ratio of 90-96 (e.g., 90, 91, 92, 93, 94, 95, 96, etc.) to 10-4 (e.g., 10, 9, 8, 7, 6, 5, 4, etc.), magnetically stirred into a paste, coated on an aluminum foil current collector, and vacuum dried at 80 ℃ for 24 hours to obtain a dried electrode sheet. The pole pieces were then punched out to the desired dimensions using a punching machine.
In yet another aspect of the present invention, a supercapacitor is provided. According to an embodiment of the invention, the supercapacitor comprises the aforementioned porous carbon/carbon nanotube composite material or the aforementioned electrode. The inventor finds that the super capacitor has higher specific capacity or greatly improved cycling stability.
It will be appreciated by those skilled in the art that the supercapacitor may have the structure and components of a conventional supercapacitor in addition to the porous carbon/carbon nanotube composite or the electrodes described above. In some embodiments, the electrodes and the symmetrical electrode plates can be packaged, and the electric-buckling symmetrical supercapacitor can be packaged by using a polypropylene film as an insulating diaphragm and a supercapacitor electrolyte.
The following describes embodiments of the present invention in detail.
Example 1: modified activated carbon and preparation of modified carbon nano tube
Carboxymethyl cellulose modified activated carbon: 0.25g of carboxymethyl cellulose and 5g of activated carbon (purchased from Korea) are subjected to solid-phase mixing, zirconium beads are added into the mixed powder to perform solid-phase ball milling reaction at the rotating speed of 300rpm for 2 hours, then 200ml of distilled water is added to separate the zirconium beads from dispersion liquid, the dispersion liquid is subjected to ultrasonic treatment for 1 hour, then the uncomplexed carboxymethyl cellulose is removed by vacuum filtration, a filter cake is collected, and the filter cake is dried in a vacuum oven at the temperature of 80 ℃ for 24 hours to obtain the carboxymethyl cellulose modified activated carbon (namely modified activated carbon) of the powder.
Polyaniline-modified carbon nanotubes: performing solid-phase mixing on 0.25g of polyaniline and 2g of carbon nano tube (purchased from rhizoma kaempferiae), adding zirconium beads into mixed powder to perform solid-phase ball milling reaction at the rotating speed of 300rpm for 7h, then adding 200ml of distilled water (the pH is controlled to be 3, and the pH is adjusted by adopting at least one of dilute hydrochloric acid and dilute ammonium bicarbonate), separating the zirconium beads from dispersion liquid, performing ultrasonic treatment on the dispersion liquid in an ultrasonic groove for 1h, finally removing unreacted polyaniline through vacuum filtration, collecting filter cakes, and drying in a vacuum oven at 80 ℃ for 24h to obtain the polyaniline modified carbon nano tube (namely modified carbon nano tube) of powder.
Example 2: preparation of the Complex
Weighing 1g of the modified activated carbon obtained in the example 1, dispersing in 100ml of water, performing ultrasonic treatment for 2 hours to obtain a uniform and stable dispersion, then adding the modified activated carbon dispersion into the dispersion of the modified carbon nanotube obtained in the example 1 (pH is adjusted to about 3, and pH is adjusted by using at least one of dilute hydrochloric acid and dilute ammonium bicarbonate) according to the mass ratio of the carbon nanotube to the activated carbon of 1:10, controlling the pH value of the mixed dispersion to be about 4, continuing ultrasonic treatment for 2 hours, performing magnetic stirring for 4 hours at room temperature, finally collecting precipitates by centrifugation (8000rpm, 10min), performing vacuum drying at 70 ℃ for 24 hours, grinding dried blocks, and sieving by using a 200-mesh sieve to obtain an activated carbon/carbon nanotube composite material A.
Example 3: preparation of active carbon/carbon nano tube composite material
And (2) calcining the activated carbon/carbon nanotube composite material A obtained in the example 2 at a high temperature, specifically, heating to 300 ℃ at a heating rate of 5 ℃/min, preserving heat for 30min, then heating to 400 ℃ and preserving heat for 1h, and naturally cooling to room temperature after heat preservation to obtain the activated carbon/carbon nanotube composite material 1.
Example 4: preparation of active carbon/carbon nano tube composite material
And (2) calcining the activated carbon/carbon nanotube composite material A obtained in the example 2 at a high temperature, wherein the heating rate is 5 ℃/min, firstly, the temperature is kept at 300 ℃ for 30min, then, the temperature is kept at 700 ℃ for 1h, and after the temperature is kept, the temperature is naturally reduced to the room temperature, so that the activated carbon/carbon nanotube composite material 2 is obtained.
Example 5: preparation of active carbon/carbon nano tube composite material
The activated carbon/carbon nanotube composite material a obtained in example 2 was calcined at a high temperature with a heating rate of 5 ℃/min, and first, the temperature was maintained at 300 ℃ for 30min, then, the temperature was increased to 800 ℃ for 1h, and then, the temperature was naturally decreased to room temperature after the temperature was maintained, so as to obtain an activated carbon/carbon nanotube composite material 3, and a scanning electron microscope photograph is shown in fig. 3.
Example 6
The difference is that the mass ratio of the carbon nano tube to the active carbon is 1:5, the obtained product is calcined at high temperature, the temperature rise rate is 5 ℃/min, the temperature is firstly preserved for 30min at 300 ℃, and then the temperature is preserved for 1h when the temperature is raised to 800 ℃ as in example 2.
Example 7
The difference is that the mass ratio of the carbon nano tube to the active carbon is 1:20, the obtained product is calcined at high temperature, the heating rate is 5 ℃/min, the temperature is firstly preserved for 30min at 300 ℃, and then the temperature is preserved for 1h at 800 ℃.
And (3) performance testing:
preparing a capacitor containing the activated carbon/carbon nanotube composite material: respectively mixing the products obtained in the above examples 2-7 with a binder PVDF according to the mass percentage of 90-96: 10-4, dispersing in NMP, magnetically stirring to obtain a paste, coating the paste on an aluminum foil current collector, and vacuum-drying at 80 ℃ for 24 hours to obtain a dried pole piece. Then, punching a pole piece with a desired size by using a punching machine, packaging symmetrical electrode pieces (namely two same electrode pieces) by using a polypropylene film as an insulating diaphragm and packaging the electrode pieces into the required buckling electric symmetrical super capacitors 1, 2, 3, 4, 5 and 6 by using super capacitor electrolyte (propylene carbonate: acetonitrile 1:1, 1mol/L boron tetrafluoride tetraethyl quaternary ammonium salt).
Preparing a capacitor containing activated carbon: mixing and dispersing activated carbon, acetylene black and a binder in NMP according to a mass ratio of 90:0.5:0.5, magnetically stirring to obtain a paste, coating the paste on an aluminum foil current collector, and drying in vacuum at 80 ℃ for 24 hours to obtain a dried pole piece. Then punching into a pole piece with a desired size by using a punching machine, packaging the symmetrical pole piece, packaging the required buckling electricity symmetrical super capacitor D1 by using a polypropylene film as an insulating diaphragm and super capacitor electrolyte (propylene carbonate: acetonitrile: 1, 1mol/L boron tetrafluoride tetra and quaternary ammonium salt)
The performance of the super capacitors 1-6 and D1 obtained above was tested by the charging and discharging test, and the test results are shown in the following table.
From the results, the modified porous carbon and the modified carbon nanotube are mixed to prepare the composite material, the dispersion is uniform, the powder resistance and the internal resistance are obviously reduced, the specific capacity is also obviously improved after further high-temperature treatment, the modified organic matter is continuously subjected to carbonization and decomposition along with the increase of the sintering temperature, the specific capacity can be further improved, the internal resistance is reduced, the specific capacity and the stability are improved, and the internal resistance is reduced.
In the description of the present invention, it is to be understood that the terms "first", "second" and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (15)
1. A preparation method of a porous carbon/carbon nanotube composite material for an electrode is characterized by comprising the following steps:
carrying out first modification treatment on the porous carbon so as to obtain modified porous carbon with negative charges;
carrying out second modification treatment on the carbon nano tube so as to obtain a modified carbon nano tube with positive charges;
mixing the modified porous carbon and the modified carbon nanotube to obtain the porous carbon/carbon nanotube composite material;
carbonizing the porous carbon/carbon nanotube composite material;
the first modification treatment of the porous carbon comprises: mixing the porous carbon with a first modifier with negative charges, and performing first solid-phase ball milling treatment on the obtained mixture;
the second modification treatment of the carbon nanotubes comprises: and mixing the carbon nano tube with a second modifier, and carrying out second solid-phase ball milling treatment on the obtained mixture, wherein the second modifier is positively charged.
2. The method of claim 1, wherein the first modifier contains at least one of a carboxyl group and a hydroxyl group.
3. The method of claim 2, wherein the first modifier is selected from at least one of carboxymethyl cellulose, a DNA strand, glucose, sucrose, and lactic acid.
4. The method as claimed in claim 1, wherein the rotation speed of the first solid phase ball milling treatment is 200-;
the porous carbon comprises at least one of activated carbon, graphene, graphite, soft carbon and hard carbon;
the mass ratio of the porous carbon to the first modifier is 4-80: 1.
5. The method according to claim 4, characterized in that the mass ratio of the porous carbon to the first modifier is 20-40: 1.
6. The method of claim 1, wherein the second modifier comprises at least one of an amino group and a quaternary ammonium cation.
7. The method of claim 6, wherein the second modifier is selected from at least one of polyaniline, polydiallyldimethylammonium chloride, and poly (p-vinylphenylmethylene- (5, 5-dimethylhydantoin) methyl-dimethyl;
the rotation speed of the second solid phase ball milling treatment is 200-;
the mass ratio of the carbon nano tube to the second modifier is 2-20: 1.
8. The method of claim 7, wherein the mass ratio of the carbon nanotubes to the second modifier is 5-10: 1.
9. The method of claim 1, wherein mixing the modified porous carbon with the modified carbon nanotubes comprises:
dispersing the modified porous carbon in a first solvent to obtain a first mixed solution;
dispersing the modified carbon nano tube in a second solvent to obtain a second mixed solution;
and mixing the first mixed solution and the second mixed solution, centrifuging the obtained mixture, and drying the obtained precipitate to obtain the porous carbon/carbon nanotube composite material.
10. The method of claim 9, wherein the pH of the second solvent is 3-5;
the dispersion comprises ultrasonic treatment, and the ultrasonic treatment time is 1-2 h;
mixing the first mixed liquid and the second mixed liquid is performed by dropping the first mixed liquid into the second mixed liquid;
mixing the modified activated carbon and the modified carbon nanotube according to the mass ratio of the carbon nanotube to the porous carbon of 1: 5-20.
11. The method as claimed in claim 1, wherein the carbonization treatment is performed by maintaining the temperature at 400-800 ℃ for 0.5-5h under an inert atmosphere;
the temperature rising speed is 2-10 ℃/min.
12. The method as claimed in claim 11, wherein the incubation at 400-800 ℃ for 0.5-5h is performed by: heating to 350 ℃ at the speed of 2-10 ℃/min, preserving the heat for 20-40min, and then heating to 800 ℃ at the temperature of 400 ℃ for 0.5-1.5 h.
13. A porous carbon/carbon nanotube composite material for an electrode, characterized in that it is prepared by the method of any one of claims 1 to 12.
14. An electrode comprising the porous carbon/carbon nanotube composite for an electrode of claim 13.
15. A supercapacitor comprising a porous carbon/carbon nanotube composite for electrodes according to claim 13 or an electrode according to claim 14.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910204832.8A CN109786128B (en) | 2019-03-18 | 2019-03-18 | Porous carbon/carbon nanotube composite material, preparation method thereof, electrode and supercapacitor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910204832.8A CN109786128B (en) | 2019-03-18 | 2019-03-18 | Porous carbon/carbon nanotube composite material, preparation method thereof, electrode and supercapacitor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109786128A CN109786128A (en) | 2019-05-21 |
| CN109786128B true CN109786128B (en) | 2021-04-30 |
Family
ID=66489434
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910204832.8A Active CN109786128B (en) | 2019-03-18 | 2019-03-18 | Porous carbon/carbon nanotube composite material, preparation method thereof, electrode and supercapacitor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109786128B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111223684B (en) * | 2020-01-07 | 2021-12-17 | 西安理工大学 | Preparation method of coffee-grounds-based supercapacitor electrode material |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1934665A (en) * | 2004-03-09 | 2007-03-21 | 阿克马法国公司 | Preparation of electrode, obtained electrode and supercapacitor comprises the same |
| CN101418089A (en) * | 2008-12-03 | 2009-04-29 | 中国热带农业科学院农产品加工研究所 | Method for preparing natural rubber-carbon nano tube composite material by using static electricity self-assembly |
| CN103357403A (en) * | 2013-07-08 | 2013-10-23 | 华南理工大学 | Method for preparing carbon-supported fuel cell double-metal electro-catalyst through electrostatic self-assembly |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8435595B2 (en) * | 2009-07-15 | 2013-05-07 | Empire Technology Development, Llc | Carbon nanotube transparent films |
-
2019
- 2019-03-18 CN CN201910204832.8A patent/CN109786128B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1934665A (en) * | 2004-03-09 | 2007-03-21 | 阿克马法国公司 | Preparation of electrode, obtained electrode and supercapacitor comprises the same |
| CN101418089A (en) * | 2008-12-03 | 2009-04-29 | 中国热带农业科学院农产品加工研究所 | Method for preparing natural rubber-carbon nano tube composite material by using static electricity self-assembly |
| CN103357403A (en) * | 2013-07-08 | 2013-10-23 | 华南理工大学 | Method for preparing carbon-supported fuel cell double-metal electro-catalyst through electrostatic self-assembly |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109786128A (en) | 2019-05-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Zhang et al. | The graphene/lanthanum oxide nanocomposites as electrode materials of supercapacitors | |
| Zhou et al. | Graphene-wrapped polyaniline nanofibers as electrode materials for organic supercapacitors | |
| CN107633954B (en) | graphene/MXene composite electrode material and application thereof | |
| Chen et al. | Al and Co co-doped α-Ni (OH) 2/graphene hybrid materials with high electrochemical performances for supercapacitors | |
| US20160225538A1 (en) | Covalently-grafted polyaniline on graphene oxide sheets and its application in electrochemical supercapacitors | |
| Hou et al. | Morphology and structure control of amine-functionalized graphene/polyaniline composite for high-performance supercapacitors | |
| CN110364372B (en) | Nickel vanadate material for supercapacitor, and preparation method and application thereof | |
| Dong et al. | Hierarchically Fe-doped porous carbon derived from phenolic resin for high performance supercapacitor | |
| Cai et al. | Two dimensional holey carbon nanosheets assisted by calcium acetate for high performance supercapacitor | |
| Wu et al. | Synthesis of chromium-doped lithium titanate microspheres as high-performance anode material for lithium ion batteries | |
| WO2016090958A1 (en) | Preparation method for mixed capacitor negative electrode slurry | |
| CN111094185A (en) | Preparation method of hexagonal molybdenum trioxide nanorod | |
| CN105118966A (en) | Sn-C composite material with high N content of lithium battery cathode and preparation method of Sn-C composite material | |
| Chandraraj et al. | Facile synthesis of graphene based mixed metal sulphide nanocomposite for energy storage applications | |
| CN115050932A (en) | Composite negative electrode material, preparation method thereof and lithium ion battery | |
| CN113415831B (en) | Ni (OH) 2 Preparation method of/graphene composite material and preparation method of supercapacitor | |
| CN109786128B (en) | Porous carbon/carbon nanotube composite material, preparation method thereof, electrode and supercapacitor | |
| Jiao et al. | Size-controllable synthesis of covalently interconnected few-shelled Fe3O4@ onion-like carbons for high-performance asymmetric supercapacitors | |
| Sun et al. | Green fabrication of pore-modulated carbon aerogels using a biological template for high-energy density supercapacitors | |
| CN109809398B (en) | Preparation method and application of graphene conductive agent dispersion liquid of high-capacity supercapacitor | |
| CN110797518A (en) | Carbon nano tube coated NiCo2S4Load SeS2Positive electrode material of lithium-sulfur battery and preparation method thereof | |
| CN108807893B (en) | Preparation method of 2-aminoanthraquinone modified graphene oxide lithium ion battery negative electrode material | |
| Song et al. | Cobalt-Porphyrin Modified Three-dimensional graphene hydrogel electrode for high performance asymmetric supercapacitors | |
| Peng et al. | Nitrogen doped carbons derived from graphene aerogel templated triazine-based conjugated microporous polymers for high-performance supercapacitors | |
| CN111533115B (en) | High-capacity high-cycle-efficiency silicon-based/graphene nanoribbon composite material and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20220121 Address after: 014300 office 520-5, administrative committee office building, Dalat banner Economic Development Zone, Ordos City, Inner Mongolia Autonomous Region Patentee after: Inner Mongolia Changxin Nano Technology Co.,Ltd. Address before: 065001 East Huaxiang Road, North Hongrun Road, Langfang Economic and Technological Development Zone, Hebei Province Patentee before: ENN GRAPHENE TECHNOLOGY Co.,Ltd. |
|
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20221201 Address after: 014300 Room 102, Office Building, Xin'ao Industrial Park, Wangaizhao Town, Dalate Banner, Ordos, Inner Mongolia Autonomous Region Patentee after: Inner Mongolia Xinminhui Nanotechnology Co.,Ltd. Address before: 014300 office 520-5, administrative committee office building, Dalat banner Economic Development Zone, Ordos City, Inner Mongolia Autonomous Region Patentee before: Inner Mongolia Changxin Nano Technology Co.,Ltd. |