CN108538638B - Super capacitor preparation method and super capacitor - Google Patents

Super capacitor preparation method and super capacitor Download PDF

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Publication number
CN108538638B
CN108538638B CN201810267083.9A CN201810267083A CN108538638B CN 108538638 B CN108538638 B CN 108538638B CN 201810267083 A CN201810267083 A CN 201810267083A CN 108538638 B CN108538638 B CN 108538638B
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graphene
oxide
preparing
reduced graphene
electrolyte
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CN108538638A (en
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聂赞相
普里帖斯·希亚拉
郑富林
杜国庆
迪乐克·奥兹特
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Shenzhen Xinyuan Flexible Technology Co ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/84—Processes for the manufacture of hybrid or EDL capacitors, or components thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H01G11/32—Carbon-based
    • H01G11/36—Nanostructures, e.g. nanofibres, nanotubes or fullerenes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/84—Processes for the manufacture of hybrid or EDL capacitors, or components thereof
    • H01G11/86—Processes for the manufacture of hybrid or EDL capacitors, or components thereof specially adapted for electrodes
    • 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 embodiment of the invention provides a super capacitor preparation method and a super capacitor, wherein the method comprises the following steps: preparing graphene: preparing reduced graphene by using graphene oxide: preparing graphene oxide by a Hummers method, and reducing the graphene oxide by heat treatment to generate reduced graphene rGO; preparation of carbon nanohorns: rapidly condensing carbon atoms of reduced graphene rGO under the condition of no catalyst to obtain carbon nanohorn agglomerates; preparing an electrode: preparing an electrode, namely preparing slurry and coating; coating the prepared slurry with an aluminum foil, and drying to obtain an electrode of the supercapacitor; assembling the super capacitor: and separating the two electrodes by using a diaphragm to form a sandwich structure, and then injecting electrolyte to realize the assembly of the super capacitor. According to the invention, the dispersibility and the conductivity of graphene are improved, so that the electrode can provide a higher conductive area, and the high capacitance of the super capacitor is realized.

Description

Super capacitor preparation method and super capacitor
Technical Field
The invention relates to the technical field of capacitors, in particular to a super capacitor and a preparation method thereof.
Background
Supercapacitors are widely used in various fields because of their high power density. One typical application is in conjunction with other energy storage devices, such as batteries. For supplementing the insufficient power output of some energy storage devices. Another advantage of supercapacitors is their ultra-long cyclability. The cycle life of the catalyst can be thousands or even tens of thousands of times. In supercapacitors, the electrode plays a critical role in its performance. In principle, the larger the conductive area of the electrode, the greater the capacitance that can be provided. Currently, most supercapacitors use activated carbon as the main electrode material. Although activated carbon has a large specific surface area, it has lower electrical conductivity than conventional carbon materials due to its poor crystal structure. Therefore, in recent years, graphene has been a hot research point for super capacitor electrode materials due to its excellent chemical and physical properties, such as ultrahigh conductivity. The excellent physical properties of graphene are theoretically data that reside in single-layer graphene. In practice, however, graphene is often present in multiple layers. Moreover, as the number of layers increases, the performance of graphene tends to be more similar to that of conventional graphite. Particularly, the strong pi-pi action enables the graphene to easily agglomerate in the processing process. Therefore, the advantages of graphene cannot be well exerted.
Disclosure of Invention
The embodiment of the invention provides a super capacitor and a preparation method thereof, and the super capacitor and the dispersibility and conductivity of graphene are improved, so that an electrode can provide a higher conductive area, and the utilization rate of materials and the performance of the super capacitor are effectively improved.
In one aspect, an embodiment of the present invention provides a method for manufacturing a supercapacitor, where the method for manufacturing a supercapacitor includes:
preparing graphene: preparing reduced graphene by using graphene oxide: preparing graphene oxide by a Hummers method, and reducing the graphene oxide by heat treatment to generate reduced graphene rGO;
preparation of carbon nanohorns: rapidly condensing carbon atoms of reduced graphene rGO under the condition of no catalyst to obtain carbon nanohorn agglomerates;
preparing an electrode: the electrode preparation comprises slurry preparation and coating, and specifically comprises the following steps: mixing reduced graphene with carbon nanohorns to prepare a slurry, the ratio of the mass of the carbon nanohorns to the mass of the multilayer graphene sheets in the electrode being between about 0.25 and about 0.5, and then adding a binder; coating the prepared slurry with an aluminum foil, and drying to obtain an electrode of the supercapacitor;
assembling the super capacitor: and separating the two electrodes by using a diaphragm to form a sandwich structure, and then injecting electrolyte to realize the assembly of the super capacitor.
On the other hand, the embodiment of the invention provides a super capacitor, wherein two electrodes of the super capacitor are separated by a diaphragm to form a sandwich structure, and then electrolyte is injected to realize the assembly of the super capacitor;
the preparation process of the electrode is as follows: preparing reduced graphene by using graphene oxide: preparing graphene oxide by a Hummers method, and reducing the graphene oxide by heat treatment to generate reduced graphene rGO; rapidly condensing carbon atoms of reduced graphene rGO under the condition of no catalyst to obtain carbon nanohorn agglomerates; the electrode preparation comprises slurry preparation and coating, and specifically comprises the following steps: mixing reduced graphene with carbon nanohorns to prepare a slurry, the ratio of the mass of the carbon nanohorns to the mass of the multilayer graphene sheets in the electrode being between about 0.25 and about 0.5, and then adding a binder; and coating the prepared slurry with an aluminum foil, and drying to obtain the electrode of the supercapacitor.
The technical scheme has the following beneficial effects: according to the invention, the dispersibility and the conductivity of graphene are improved, so that the electrode can provide a higher conductive area, and the high capacitance of the super capacitor is realized. Compared with the prior art, the method has the advantages of simple operation and low cost.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a flow chart of a method for manufacturing a supercapacitor according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a super capacitor according to an embodiment of the present invention;
fig. 3 is a schematic diagram of the structure of an electrode according to the first aspect of an embodiment of the present invention and TEM (Transmission Electron Microscope) and SEM (Scanning Electron Microscope) images;
fig. 4 is a schematic structural view of carbon nanohorn agglomerates used in the electrode shown in fig. 3 according to an embodiment of the present invention;
FIG. 5 is a photograph of a graphene sheet with different thermal treatment times and a graph of Raman results for an embodiment of the present invention;
FIG. 6 is a graph of resistivity as a function of voltage for a series of different electrode materials in a supercapacitor or current collector in accordance with an embodiment of the present invention;
FIG. 7 shows a cyclic voltammogram of a supercapacitor obtained by using an embodiment of the present invention, and graphene electrode maps of capacitance values and different heat treatment times;
in fig. 8, a is a graph of the overall resistance versus heat treatment time for a supercapacitor and a supercapacitor with electrodes only with rGO added and no carbon nanohorns added in an embodiment of the present invention; graph b is a graph of capacitance versus frequency for a supercapacitor (and for a supercapacitor with electrodes only added to rGO and no carbon nanohorns) in an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, a flowchart of a method for manufacturing a super capacitor according to an embodiment of the present invention is shown, where the method for manufacturing a super capacitor includes:
101. preparing graphene: preparing reduced graphene by using graphene oxide: preparing graphene oxide by a Hummers method, and reducing the graphene oxide by heat treatment to generate reduced graphene rGO;
102. preparation of carbon nanohorns: rapidly condensing carbon atoms of reduced graphene rGO under the condition of no catalyst to obtain carbon nanohorn agglomerates;
103. preparing an electrode: the electrode preparation comprises slurry preparation and coating, and specifically comprises the following steps: mixing reduced graphene with carbon nanohorns to prepare a slurry, the ratio of the mass of the carbon nanohorns to the mass of the multilayer graphene sheets in the electrode being between about 0.25 and about 0.5, and then adding a binder; coating the prepared slurry with an aluminum foil, and drying to obtain an electrode of the supercapacitor;
104. assembling the super capacitor: and separating the two electrodes by using a diaphragm to form a sandwich structure, and then injecting electrolyte to realize the assembly of the super capacitor.
Preferably, the preparing of graphene oxide by Hummers method, and the reducing of graphene oxide by thermal treatment to produce reduced graphene rGO comprises:
preparing graphene oxide by a Hummers method, and placing a dry graphene oxide sheet in an environment of 350 ℃ for rapid heating to enable the graphene oxide sheet to undergo rapid reduction reaction to generate reduced graphene rGO; during the reduction reaction, the functional group of the graphene oxide is decomposed to generate CO2CO and H2O gas, wherein graphene oxide is stripped in the generation process of the gas to obtain reduced graphene rGO sheets, and the specific surface area of the generated reduced graphene rGO sheets is 500-1200 m2g-1。
Preferably, after carbon atoms of reduced graphene rGO are rapidly condensed to obtain carbon nanohorn agglomerates in the absence of a catalyst, the diameter of the obtained single carbon nanohorn is 3-5 nm, the length of the single carbon nanohorn is 30-50 nm, and the diameter of the obtained carbon nanohorn agglomerates is 60-120 nm.
Preferably, the reduced graphene is mixed with the carbon nanohorns to prepare a slurry, and the ratio of the mass of the carbon nanohorns to the mass of the multilayer graphene sheets in the electrode is between 0.3 and 0.4; and improving the performance of the super-capacitor by adding metal oxides, including but not limited to: alumina, oxidized state, manganese oxide, cobalt oxide; the ratio of the mass of the oxide component to the combined mass of the plurality of carbon nanohorns and the multilayer graphene sheet is 85:15 to 99: 1; the binder comprises at least one of polytetrafluoroethylene, styrene butadiene rubber, ethyl cellulose or polyvinylidene fluoride.
Preferably, the diaphragm comprises: polypropylene films, glass films, polyethylene films, cellulose sheet films, polyethylene composite films, polypropylene composite films; the electrolyte in the electrolyte is a liquid electrolyte or a gel electrolyte; the liquid electrolyte is: NaOH, H2SO4HCl, or ionic liquids; the gel electrolyte includes: polyethylene oxide gel electrolyte; the electrolyte includes: tetraethylammonium tetrafluoroborate in propylene carbonate.
Corresponding to the above method embodiment, as shown in fig. 2, which is a schematic structural diagram of a super capacitor according to an embodiment of the present invention, the super capacitor separates two electrodes 3 and 4 by a diaphragm 5 to form a sandwich structure, and then injects an electrolyte 1 and 2 to realize the assembly of the super capacitor;
the preparation process of the electrode is as follows: preparing reduced graphene by using graphene oxide: preparing graphene oxide by a Hummers method, and reducing the graphene oxide by heat treatment to generate reduced graphene rGO; rapidly condensing carbon atoms of reduced graphene rGO under the condition of no catalyst to obtain carbon nanohorn agglomerates; the electrode preparation comprises slurry preparation and coating, and specifically comprises the following steps: mixing reduced graphene with carbon nanohorns to prepare a slurry, the ratio of the mass of the carbon nanohorns to the mass of the multilayer graphene sheets in the electrode being between about 0.25 and about 0.5, and then adding a binder; and coating the prepared slurry with an aluminum foil, and drying to obtain the electrode of the supercapacitor.
Preferably, the preparing of graphene oxide by Hummers method, and the reducing of graphene oxide by thermal treatment to produce reduced graphene rGO comprises:
preparing graphene oxide by a Hummers method, and placing a dry graphene oxide sheet in an environment of 350 ℃ for rapid heating to enable the graphene oxide sheet to undergo rapid reduction reaction to generate reduced graphene rGO; during the reduction reaction, the functional group of the graphene oxide is decomposed to generate CO2CO and H2O gas, in which graphene oxide is exfoliated during the generation of the gas,obtaining reduced graphene rGO sheets, wherein the specific surface area of the produced reduced graphene rGO sheets is 500-1200 m2g-1。
Preferably, after carbon atoms of the raw graphene rGO are rapidly condensed without a catalyst to obtain the carbon nanohorn aggregate, the diameter of the obtained single carbon nanohorn is 3 nm-5 nm, the length of the single carbon nanohorn is 30 nm-50 nm, and the diameter of the obtained carbon nanohorn aggregate is 60 nm-120 nm.
Preferably, the reduced graphene is mixed with the carbon nanohorns to prepare a slurry, and the ratio of the mass of the carbon nanohorns to the mass of the multilayer graphene sheets in the electrode is between 0.3 and 0.4; and improving the performance of the super-capacitor by adding metal oxides, including but not limited to: alumina, oxidized state, manganese oxide, cobalt oxide; the ratio of the mass of the oxide component to the combined mass of the plurality of carbon nanohorns and the multilayer graphene sheet is 85:15 to 99: 1; the binder comprises at least one of polytetrafluoroethylene, styrene butadiene rubber, ethyl cellulose or polyvinylidene fluoride.
Preferably, the diaphragm comprises: polypropylene films, glass films, polyethylene films, cellulose sheet films, polyethylene composite films, polypropylene composite films; the electrolyte in the electrolyte is a liquid electrolyte or a gel electrolyte; the liquid electrolyte is: NaOH, H2SO4HCl, or ionic liquids; the gel electrolyte includes: polyethylene oxide gel electrolyte; the electrolyte includes: tetraethylammonium tetrafluoroborate in propylene carbonate.
The super capacitor provided by the embodiment of the invention is a capacitor with extremely high capacitance. It typically has two electrodes separated by a separator containing an electrolyte. For graphene supercapacitors, a typical problem is their low utilization of active species due to agglomeration of graphene during processing. And graphene exhibits low conductivity due to defects introduced during the preparation process.
According to the preparation method of the supercapacitor electrode, the reduced graphene is obtained through simple heat treatment. Compared with untreated graphene, the obtained reduced graphene has better conductivity. And then, a carbon material (carbon nanohorn) with a special nano structure is added to effectively inhibit the agglomeration of the graphene in the processing process.
The manufacturing steps of the super capacitor related to the embodiment of the invention comprise:
the first step is as follows: and (3) preparing graphene. The modified Hummers method prepares graphene oxide, which is reduced by a simple heat treatment. And (3) placing the dried graphene oxide sheet at about 350 ℃ for rapid heating to enable the graphene oxide sheet to undergo rapid reduction reaction to generate the reduced graphene oxide rGO. 1g of dried graphene oxide sheets produced approximately 0.33g of reduced graphene. During the reduction reaction, the functional group of the graphene oxide is decomposed to generate CO2CO and H2And (4) O gas. Graphene oxide is exfoliated during the formation of these gases, resulting in very low density rGO sheets. The oxygen-containing functional group partially disappears after the reduction process and about 10% of the carbon atoms escape in the form of gas, causing defects in the structure. The specific surface area of the rGO generated by the method is about 500-1200 m < 2 > 2 g-1.
The second step is that: preparation of carbon nanohorns: and (3) rapidly condensing carbon atoms under the condition of no catalyst to obtain the carbon nanohorn agglomerates. The average diameter of the obtained single carbon nanohorn is about 3-5 nm, and the average length is about 30-50 nm. The average diameter of the obtained carbon nanohorn agglomerates is about 60-120 nm.
The third step: preparing an electrode: the preparation of the electrode comprises the preparation of slurry and coating. Preparing slurry: the reduced graphene is mixed with the carbon nanohorns, preferably, the ratio of the mass of the carbon nanohorns to the mass of the multilayer graphene sheets in the electrode is between about 0.25 and about 0.5, more preferably between about 0.3 and about 0.4. Most preferably, the mass ratio of the plurality of carbon nanohorns to the multilayer graphene sheets is about 1: 3. In addition, the super-capacitive performance can be improved by adding metal oxides (including but not limited to alumina, oxidation state, manganese oxide, cobalt oxide). A preferred ratio of the mass of the oxide component to the combined mass of the plurality of carbon nanohorns and the multilayer graphene sheets is from about 85:15 to about 99:1, most preferably about 20: 1. in certain preferred embodiments, the electrode comprises a plurality of carbon nanohorns, a plurality of graphene sheets and a plurality of metal or alloy nanoparticles in a mass ratio of 1:3: 80. In order to improve the binding force of the active substance, a binder may be added. The binder may be any suitable binder. Preferably, the binder comprises at least one of polytetrafluoroethylene, styrene butadiene rubber, ethyl cellulose or polyvinylidene fluoride. For example, the binder may include polytetrafluoroethylene in deionized water. Where the electrode comprises a binder, the electrode may comprise any suitable amount of binder. In certain embodiments, the electrode comprises about 5% by weight binder. In such an embodiment, 5% by weight of the binder may be comprised of 2% by weight of polytetrafluoroethylene in ionic water. The resulting slurry coated current collector is typically aluminum foil and dried to provide the electrode of the supercapacitor.
The fourth step: assembling the super capacitor: the super capacitor is assembled by forming the electrodes and the diaphragm into a sandwich structure. And then injecting electrolyte to realize the operation. The membrane includes, but is not limited to, any suitable membrane. For example, the separator may include a polypropylene film, a glass film, a polyethylene film, a cellulose sheet film, or the like. A polyethylene/propylene composite film is preferred as the separator. The electrolyte may be any suitable electrolyte. The electrolyte may be a liquid electrolyte or a gel electrolyte, such as a polyethylene oxide gel electrolyte. Preferably, the electrolyte comprises a solution of tetraethylammonium tetrafluoroborate in propylene carbonate. The electrolyte may comprise NaOH or other bases, H2SO4HCl or other acids or electrolytes may also be ionic liquids.
For example, the following steps are carried out:
graphene oxide was obtained by Hummers method: and (3) adding 2g of graphite into 50mL of 70% sulfuric acid, performing ultrasonic treatment for 1h, and adding 1M potassium permanganate to mix. And (5) carrying out ultrasonic treatment for 2h to obtain a graphene oxide suspension. Then diluted by adding 5 times of water. Finally adding hydrogen peroxide to remove excessive potassium permanganate. And separating and drying to obtain the graphene oxide.
Reducing graphene: reduced graphene is obtained by simple heat treatment. And heating 1g of the obtained graphene oxide and a crucible in the air to 350 ℃, keeping the temperature for a certain time, and naturally cooling to obtain the reduced graphene. As shown in fig. 5, the colors appear different in time for different treatments. As the heating time increased, the color of the reduced graphene changed from brown-yellow to black. This is caused by the microstructure change caused by the decomposition of the surface functional groups of graphene during heating. Raman image analysis shows that the proportion of the D peak and the G peak can be effectively reduced by heat treatment. Saturation was reached in 5 hours.
Example 1:
50mg of carbon nanohorns and 50mg of reduced graphene were dispersed in 50mL of deionized water to obtain a uniform solution. Suction filtering to obtain 2cm2The carbon nanohorn and reduced graphene mixed film of (1). And transferring the film onto an aluminum foil current collector to obtain the electrode for assembling the super capacitor. Fig. 3 is a schematic diagram of the structure of an electrode according to the first aspect of an embodiment of the present invention and TEM (Transmission Electron Microscope) and SEM (Scanning Electron Microscope) images; fig. 4 is a schematic view of the structure of carbon nanohorn agglomerates used in the electrode shown in fig. 3. Fig. 3 shows a composite structure of carbon nanohorns and reduced graphene. It was confirmed that the carbon nanohorns were uniformly dispersed on the graphene sheet. The carbon nanohorns can act as a scaffold to inhibit the agglomeration of graphene sheets, so that the composite structure can provide a large conductive area.
A celgard3500 diaphragm is used as a diaphragm of the super capacitor, and the diaphragm and two electrodes form a sandwich structure. The electrolyte is 1M tetraethylammonium tetrafluoroborate in propionate carbonate solution. The resulting electrical test is shown in FIG. 5. From the cyclic voltammograms, it can be shown that the addition of carbon nanohorns greatly increases the capacitance of the supercapacitor. The study of the relationship between the heat treatment time and the capacitance showed that the heat treatment time of two hours was the optimum heat treatment time.
In fig. 8, a is a graph of the overall resistance versus heat treatment time for a supercapacitor and a supercapacitor with electrodes added with rGO only and without carbon nanohorns in an embodiment of the present invention. The results from the figure show that the addition of carbon nanohorns can effectively increase the capacity of the supercapacitor.
In fig. 8, a is a graph of capacitance versus frequency for a supercapacitor and a supercapacitor with electrodes added with rGO only and without carbon nanohorns in an embodiment of the present invention. The figure shows that the carbon nanohorns significantly increase the capacitance of the supercapacitor over a range of frequencies.
Example 2:
5mg of multi-walled carbon nanotubes (or single-walled carbon nanotubes or metallic nickel nanoparticles) and 95mg of reduced graphene were dispersed in 50mL of deionized water to obtain a uniform solution. Suction filtering to obtain 2cm2The carbon nanohorn and reduced graphene mixed film of (1). And transferring the film onto an aluminum foil current collector to obtain the electrode for assembling the super capacitor. FIG. 6 is a graph of resistivity as a function of voltage for a series of different electrode materials in a supercapacitor or current collector in accordance with an embodiment of the present invention; FIG. 7 shows a cyclic voltammogram of a supercapacitor obtained by using an embodiment of the present invention, and graphene electrode maps of capacitance values and different heat treatment times; figure 7 shows the resistivity of these materials as a function of voltage. Line 1 corresponds to electrode material with only rGO added and no other additions. Line 2 corresponds to the electrode material with the addition of rGO and at the same time 5 wt% of multi-walled carbon nanotubes. Line 3 corresponds to the electrode material with rGO added with 5 wt% Ni nanoparticles. Line 1104 corresponds to the electrode material with the addition of rGO and also 5 wt% carbon nanohorns. The carbon nanohorn is a single-walled carbon nanohorn.
A celgard3500 diaphragm is used as a diaphragm of the super capacitor, and the diaphragm and two electrodes form a sandwich structure. The electrolyte is 1M tetraethylammonium tetrafluoroborate in propionate carbonate solution.
The technical scheme has the following beneficial effects: according to the invention, the dispersibility and the conductivity of graphene are improved, so that the electrode can provide a higher conductive area, and the high capacitance of the super capacitor is realized. Compared with the prior art, the method has the advantages of simple operation and low cost.
It should be understood that the specific order or hierarchy of steps in the processes disclosed is an example of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged without departing from the scope of the present disclosure. The accompanying method claims present elements of the various steps in a sample order, and are not intended to be limited to the specific order or hierarchy presented.
In the foregoing detailed description, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments of the subject matter require more features than are expressly recited in each claim. Rather, as the following claims reflect, invention lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. To those skilled in the art; various modifications to these embodiments will be readily apparent, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
What has been described above includes examples of one or more embodiments. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the aforementioned embodiments, but one of ordinary skill in the art may recognize that many further combinations and permutations of various embodiments are possible. Accordingly, the embodiments described herein are intended to embrace all such alterations, modifications and variations that fall within the scope of the appended claims. Furthermore, to the extent that the term "includes" is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term "comprising" as "comprising" is interpreted when employed as a transitional word in a claim. Furthermore, any use of the term "or" in the specification of the claims is intended to mean a "non-exclusive or".
The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may be stored in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. For example, a storage medium may be coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC, which may be located in a user terminal. In the alternative, the processor and the storage medium may reside in different components in a user terminal.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (4)

1. A preparation method of a super capacitor is characterized by comprising the following steps:
preparing graphene: preparing reduced graphene by using graphene oxide: preparing graphene oxide by a Hummers method, and reducing the graphene oxide by heat treatment to generate reduced graphene;
preparation of carbon nanohorns: rapidly condensing carbon atoms of reduced graphene under the condition of no catalyst to obtain carbon nanohorn agglomerates, wherein the diameter of the obtained single carbon nanohorn is 3-5 nm, the length of the single carbon nanohorn is 30-50 nm, and the diameter of the obtained carbon nanohorn agglomerates is 60-120 nm;
preparing an electrode: the electrode preparation comprises slurry preparation and coating, and specifically comprises the following steps: mixing reduced graphene and carbon nanohorns to prepare slurry, and then adding an adhesive; coating an aluminum foil on the prepared slurry, and drying to obtain an electrode of the supercapacitor, wherein the electrode further comprises a metal oxide, and the mass ratio of the reduced graphene to the carbon nanohorn to the metal oxide is 1:3: 80;
assembling the super capacitor: separating the two electrodes by using a diaphragm to form a sandwich structure, and then injecting electrolyte to realize the assembly of the super capacitor;
wherein the preparing of the slurry by mixing the reduced graphene with the carbon nanohorns and then adding the binder comprises: the performance of the super-capacitance is improved by adding metal oxides, wherein the metal oxides comprise: at least one of alumina, titanium oxide, manganese oxide and cobalt oxide; the adhesive comprises one of polytetrafluoroethylene, styrene butadiene rubber, ethyl cellulose or polyvinylidene fluoride;
preparing graphene oxide by a Hummers method, and placing dry graphene oxide in an air environment at 350 ℃ for rapid heating to perform rapid reduction reaction to generate reduced graphene, wherein the heat treatment time is 2 hours; during the reduction reaction, the functional group of the graphene oxide is decomposed to generate CO2CO and H2O gas, the oxidized graphene is stripped in the generation process of the gas to obtain reduced graphene, and the specific surface area of the generated reduced graphene is 500-1200 m2 g-1。
2. The method for preparing the supercapacitor according to claim 1, wherein the separator is: polypropylene film, glass film, polyethylene film, cellulose sheet film, polyethylene composite film or polypropylene composite film; the electrolyte in the electrolyte is a liquid electrolyte or a gel electrolyte; the liquid electrolyte is: NaOH, H2SO4HCl or ionic liquids; the gel electrolyte is as follows: polyethylene oxide gel electrolyte; the electrolyte is as follows: fourthlyEthyl ammonium tetrafluoroborate in propylene carbonate.
3. A super capacitor is characterized in that two electrodes of the super capacitor are separated by a diaphragm to form a sandwich structure, and then electrolyte is injected to realize the assembly of the super capacitor;
the preparation process of the electrode is as follows: preparing reduced graphene by using graphene oxide: preparing graphene oxide by a Hummers method, and reducing the graphene oxide by heat treatment to generate reduced graphene; rapidly condensing carbon atoms of reduced graphene under the condition of no catalyst to obtain carbon nanohorn agglomerates, wherein the diameter of the obtained single carbon nanohorn is 3-5 nm, the length of the single carbon nanohorn is 30-50 nm, and the diameter of the obtained carbon nanohorn agglomerates is 60-120 nm; the electrode preparation comprises slurry preparation and coating, and specifically comprises the following steps: mixing reduced graphene and carbon nanohorns to prepare slurry, and then adding an adhesive; coating an aluminum foil on the prepared slurry, and drying to obtain an electrode of the supercapacitor, wherein the electrode further comprises a metal oxide, and the mass ratio of the reduced graphene to the carbon nanohorn to the metal oxide is 1:3: 80;
wherein the preparing of the slurry by mixing the reduced graphene with the carbon nanohorns and then adding the binder comprises: the performance of the super-capacitance is improved by adding metal oxides, wherein the metal oxides comprise: at least one of alumina, titanium oxide, manganese oxide and cobalt oxide; the adhesive comprises one of polytetrafluoroethylene, styrene butadiene rubber, ethyl cellulose or polyvinylidene fluoride;
preparing graphene oxide by a Hummers method, and placing dry graphene oxide in an air environment at 350 ℃ for rapid heating to perform rapid reduction reaction to generate reduced graphene, wherein the heat treatment time is 2 hours; during the reduction reaction, the functional group of the graphene oxide is decomposed to generate CO2CO and H2O gas, the oxidized graphene is stripped in the generation process of the gas to obtain reduced graphene, and the specific surface area of the generated reduced graphene is 500-1200 m2 g-1。
4. The supercapacitor of claim 3, wherein the separator is: polypropylene film, glass film, polyethylene film, cellulose sheet film, polyethylene composite film or polypropylene composite film; the electrolyte in the electrolyte is a liquid electrolyte or a gel electrolyte; the liquid electrolyte is: NaOH, H2SO4HCl or ionic liquids; the gel electrolyte is as follows: polyethylene oxide gel electrolyte; the electrolyte is as follows: tetraethylammonium tetrafluoroborate in propylene carbonate.
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