CN111816459A - Preparation method of graphene current collector - Google Patents
Preparation method of graphene current collector Download PDFInfo
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- CN111816459A CN111816459A CN202010630040.XA CN202010630040A CN111816459A CN 111816459 A CN111816459 A CN 111816459A CN 202010630040 A CN202010630040 A CN 202010630040A CN 111816459 A CN111816459 A CN 111816459A
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- graphene
- current collector
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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
- H01G11/66—Current collectors
- H01G11/68—Current collectors characterised by their material
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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
- H01G11/86—Processes for the manufacture of hybrid or EDL capacitors, or components thereof specially adapted for electrodes
Abstract
The invention discloses a preparation method of a graphene current collector, which is characterized by comprising the following steps: mixing graphene, a binder and a solvent to obtain a graphene suspension; filtering the graphene suspension in vacuum through a microporous filter membrane, adding a high molecular solution into a precursor filter cake obtained by filtering to obtain a mixed solution, filtering the mixed solution until the mixed solution is completely filtered, and drying the filter cake completely filtered in a drying oven at 50-100 ℃ to obtain a graphene film; and taking out the graphene film and the microporous filter membrane, and treating at 300-1200 ℃ under a protective atmosphere to obtain the graphene current collector. The cycle life of the electrode material can be prolonged.
Description
Technical Field
The embodiment of the invention relates to the field of composite material preparation, in particular to a preparation method of a graphene current collector.
Background
The current collector is a structure or a part for collecting current, has the main functions of collecting the current generated by the active substances of the battery, providing an electronic channel, accelerating charge transfer, improving the coulomb charging and discharging efficiency, and meets the requirements of high conductivity, good mechanical property, light weight, small internal resistance and the like as the current collector.
The super capacitor is a novel energy storage device, has the advantages of high power density (more than 10 times of that of a common battery), long cycle life (the cycle frequency can reach more than 10 ten thousand times), good rapid charge and discharge performance and the like, and is widely applied to the military field, mobile communication devices, computers and hybrid power lamps of electric vehicles. Generally, a supercapacitor is mainly assembled from an electrode active material layer, an electrolyte, a separator, a current collector, a case, and the like. The energy density of the conventional super capacitor is generally lower, and the influence factors of the energy density of the super capacitor mainly comprise the capacitance of an electrode material, the voltage of a system and the proportion of the electrode material in the total weight of an electrode active material layer, a current collector and a shell material, so that the energy storage performance of the electrode material is improved, the weight of each component material of the device is reduced, and the performance of the device can be effectively improved. Among them, reducing the mass of the current collector is an effective method for increasing the energy density.
Graphene is a two-dimensional carbon atom crystal discovered by Andre K haim (Andre K. geim) and the like at manchester university in 2004, and has excellent properties, and a graphene film prepared from graphene is light in weight, and simultaneously, high mechanical properties and high conductivity can also meet basic performance indexes of current collector application, so that the graphene film prepared based on graphene can be used as a current collector, and the quality of the current collector can be reduced.
Generally, the positive current collector adopts an aluminum foil, the negative current collector adopts a metal current collector such as a copper foil, and the like, and the metal current collector directly contacts the electrolyte in the charging process, so that the positive current collector and the negative current collector are easy to corrode, and the cycle life of the supercapacitor is further influenced. In addition, the metal current collector is not firmly adhered to the active material, and the interface is difficult to be tightly combined, so that the utilization rate of the electrode material is influenced, and the contact resistance is increased.
Disclosure of Invention
Based on the above problems, embodiments of the present invention provide a method for preparing a graphene current collector, so as to improve the cycle life of an electrochemical capacitor.
The embodiment of the invention provides a preparation method of a graphene current collector, which comprises the following steps:
the preparation method of the graphene current collector is characterized by comprising the following steps:
(1) mixing graphene, a binder and a solvent to obtain a graphene suspension, wherein the content of graphene in the graphene suspension is 0.005 mg/ml-10 mg/ml;
(2) filtering the graphene suspension in vacuum through a microporous filter membrane, adding a high molecular solution into a precursor filter cake obtained by filtering to obtain a mixed solution, filtering the mixed solution until the mixed solution is completely filtered, and drying the filter cake completely filtered in a drying oven at 50-100 ℃ to obtain a graphene film;
(3) and taking out the graphene film and the microporous filter membrane, and treating at 300-1200 ℃ under a protective atmosphere to obtain the graphene current collector.
Therefore, according to the preparation method of the graphene current collector, which is provided by the embodiment of the invention, the graphene which is easy to prepare into integrity and uniformity from the graphene suspension is used as the substrate substance, the high polymer is added to obtain the graphene with stronger mechanical property, and then the adhesive is used, so that the adhesive force is further enhanced, and the cycle service life of the battery is prolonged.
In addition, the preparation method of the graphene current collector according to the above embodiment of the present invention may further have the following additional technical features:
in some embodiments of the present invention, the binder in step (1) is at least one of sodium carboxymethyl cellulose, styrene-butadiene rubber, polyvinyl alcohol, polytetrafluoroethylene, or polyurethane.
In some embodiments of the present invention, the solvent in step (1) is at least one of water, absolute ethanol, N-dimethylformamide, and dimethylsulfoxide.
In some embodiments of the present invention, the polymer solution in step (2) is a polyvinyl alcohol solution, a polyvinyl pyrrolidone solution or a polyethylene oxide solution, and the polyvinyl alcohol, the polyvinyl pyrrolidone or the polyethylene oxide accounts for 0.05% to 10% of the total mass of the whole mixed solution.
In some embodiments of the invention, the mass ratio of the graphene to the binder is (1-50): 1, the concentration of the macromolecular solution is 0.5-10%.
In some embodiments of the present invention, further, the graphene thin film has a thickness of 1 μm to 15 μm.
Further, the protective atmosphere in the step (3) is pure argon or argon/hydrogen mixed gas.
Further, the time for processing the graphene and the microporous filter membrane in the step (3) is 30 min-3 h.
Furthermore, the microporous filter membrane is a mixed fiber membrane, a nylon membrane or an acetate membrane, and the aperture of the micropores is 50 nm-250 nm.
Further, after the graphene, the binder and the solvent are mixed in the step (1), the graphene suspension is obtained through ultrasonic dispersion for 0.5-3 hours.
The preparation method of the graphene current collector provided by the embodiment of the invention has the following beneficial effects:
(1) according to the invention, graphene which is easy to prepare into complete and uniform graphene suspension is used as a substrate material, high polymers are added to obtain graphene with strong mechanical properties, and then a binder is used, so that the adhesion is further enhanced, and the cycle service life of the battery is prolonged;
(2) the preparation method has simple equipment and simple operation, and is easy to realize large-scale industrial production;
(3) the graphene current collector prepared by the method has the advantages of uniform thickness, light weight, high mechanical strength and strong conductivity, can effectively reduce the weight, and can be used as an ideal current collector of a super capacitor.
Detailed Description
The present invention will be described in further detail with reference to examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention.
In the first embodiment, the first step is,
the preparation method of the graphene current collector is characterized by comprising the following steps:
(1) weighing 15g of sodium carboxymethylcellulose, adding into 10Kg of deionized water, ultrasonically mixing uniformly by using a stirrer, and then adding 500g of graphene prefabricated liquid, stirring and mixing uniformly. The graphene suspension liquid is a suspension liquid of graphene and water, the graphene suspension liquid contains 100g of graphene, a proper amount of deionized water is added to adjust the content of the graphene, finally ultrasonic dispersion treatment is carried out for 1h, and the graphene suspension liquid is obtained through filtration, wherein the content of the graphene in the graphene suspension liquid is controlled to be 8 mg/ml;
(2) the prepared graphene suspension is subjected to vacuum filtration through a nylon membrane with the micropore aperture of 100nm, when no obvious filtrate is seen on the precursor cake, a polyvinyl alcohol aqueous solution is added on the micropore filtration membrane for continuous filtration until the filtration is complete, and the filter cake which is completely filtered is placed in a drying oven at 50 ℃ for drying to obtain a graphene film;
(3) and taking out the graphene film and the microporous filter membrane, and treating for 1.5h at 1000 ℃ under the pure argon protective atmosphere to obtain the graphene current collector.
In the second embodiment, the first embodiment of the method,
the preparation method of the graphene current collector is characterized by comprising the following steps:
(1) weighing 50g of styrene butadiene rubber, adding the styrene butadiene rubber into 10Kg of deionized water, ultrasonically mixing the styrene butadiene rubber and the deionized water uniformly by adopting a stirrer, and then adding 500g of graphene prefabricated liquid, stirring and mixing the graphene prefabricated liquid uniformly. The graphene suspension liquid is a suspension liquid of graphene and water, the graphene suspension liquid contains 100g of graphene, a proper amount of deionized water is added to adjust the content of the graphene, finally ultrasonic dispersion treatment is carried out for 1h, and the graphene suspension liquid is obtained through filtration, wherein the content of the graphene in the graphene suspension liquid is controlled to be 8 mg/ml;
(2) the prepared graphene suspension is subjected to vacuum filtration through a nylon membrane with the micropore aperture of 100nm, when no obvious filtrate is seen on the precursor cake, a polyvinyl alcohol aqueous solution is added on the micropore filtration membrane for continuous filtration until the filtration is complete, and the filter cake which is completely filtered is placed in a drying oven at 50 ℃ for drying to obtain a graphene film;
(3) and taking out the graphene film and the microporous filter membrane, and treating for 1.5h at 1000 ℃ under the pure argon protective atmosphere to obtain the graphene current collector.
In the third embodiment, the first step is that,
the preparation method of the graphene current collector is characterized by comprising the following steps:
(1) weighing 50g of polyvinyl alcohol, adding the polyvinyl alcohol into 10Kg of deionized water, ultrasonically mixing the polyvinyl alcohol and the deionized water uniformly by using a stirrer, and then adding 500g of graphene prefabricated liquid, stirring and mixing the graphene prefabricated liquid uniformly. The graphene suspension liquid is a suspension liquid of graphene and water, the graphene suspension liquid contains 100g of graphene, a proper amount of deionized water is added to adjust the content of the graphene, finally ultrasonic dispersion treatment is carried out for 1h, and the graphene suspension liquid is obtained through filtration, wherein the content of the graphene in the graphene suspension liquid is controlled to be 8 mg/ml;
(2) the prepared graphene suspension is subjected to vacuum filtration through a nylon membrane with the micropore aperture of 100nm, when no obvious filtrate is seen on the precursor cake, a polyvinyl alcohol aqueous solution is added on the micropore filtration membrane for continuous filtration until the filtration is complete, and the filter cake which is completely filtered is placed in a drying oven at 50 ℃ for drying to obtain a graphene film;
(3) and taking out the graphene film and the microporous filter membrane, and treating for 1.5h at 1000 ℃ under the pure argon protective atmosphere to obtain the graphene current collector.
In the fourth embodiment, the first step is that,
the preparation method of the graphene current collector is characterized by comprising the following steps:
(1) weighing 25g of polytetrafluoroethylene, adding the polytetrafluoroethylene into 10Kg of deionized water, ultrasonically mixing the polytetrafluoroethylene and the deionized water uniformly by using a stirrer, and then adding 500g of graphene prefabricated liquid, stirring and mixing the graphene prefabricated liquid uniformly. The graphene suspension liquid is a suspension liquid of graphene and water, the graphene suspension liquid contains 100g of graphene, a proper amount of deionized water is added to adjust the content of the graphene, finally ultrasonic dispersion treatment is carried out for 1h, and the graphene suspension liquid is obtained through filtration, wherein the content of the graphene in the graphene suspension liquid is controlled to be 8 mg/ml;
(2) the prepared graphene suspension is subjected to vacuum filtration through a nylon membrane with the micropore aperture of 100nm, when no obvious filtrate is seen on the precursor cake, a polyvinyl alcohol aqueous solution is added on the micropore filtration membrane for continuous filtration until the filtration is complete, and the filter cake which is completely filtered is placed in a drying oven at 50 ℃ for drying to obtain a graphene film;
(3) and taking out the graphene film and the microporous filter membrane, and treating for 1.5h at 1000 ℃ under the pure argon protective atmosphere to obtain the graphene current collector.
In the fifth embodiment, the first step is,
the preparation method of the graphene current collector is characterized by comprising the following steps:
(1) weighing 20g of polyurethane, adding the polyurethane into 10Kg of deionized water, ultrasonically mixing the polyurethane and the deionized water uniformly by using a stirrer, and then adding 500g of graphene prefabricated liquid, stirring and mixing the mixture uniformly. The graphene suspension liquid is a suspension liquid of graphene and water, the graphene suspension liquid contains 100g of graphene, a proper amount of deionized water is added to adjust the content of the graphene, finally ultrasonic dispersion treatment is carried out for 1h, and the graphene suspension liquid is obtained through filtration, wherein the content of the graphene in the graphene suspension liquid is controlled to be 8 mg/ml;
(2) the prepared graphene suspension is subjected to vacuum filtration through a nylon membrane with the micropore aperture of 100nm, when no obvious filtrate is seen on the precursor cake, a polyvinyl alcohol aqueous solution is added on the micropore filtration membrane for continuous filtration until the filtration is complete, and the filter cake which is completely filtered is placed in a drying oven at 50 ℃ for drying to obtain a graphene film;
(3) and taking out the graphene film and the microporous filter membrane, and treating for 1.5h at 1000 ℃ under the pure argon protective atmosphere to obtain the graphene current collector.
Comparative example:
(1) taking 500g of graphene prefabricated liquid, stirring and mixing uniformly, wherein the graphene prefabricated liquid is a suspension of graphene and water, the graphene prefabricated liquid contains 100g of graphene, adding a proper amount of deionized water to adjust the content of the graphene, and filtering to obtain a graphene suspension, wherein the content of the graphene in the graphene suspension is controlled at 8 mg/ml;
(2) vacuum-filtering the graphene suspension by using a mixed fiber membrane with the micropore diameter of 100nm, filtering to obtain a filter cake, and drying the filter cake in an oven at 50 ℃ to obtain a graphene film;
(3) and taking out the graphene film and the microporous filter membrane, and treating for 1.5h at 1000 ℃ under the pure argon protective atmosphere to obtain the graphene current collector.
Effect embodiment:
1. conductivity test
The graphene current collector prepared in the embodiment of the invention and the graphite prepared in the comparative example are measured by adopting a four-probe method
The electrical conductivity of the olefinic current collector. The test results are shown in table 1:
sample number | Example one | Example two | EXAMPLE III | Example four | EXAMPLE five | Comparative example |
Conductivity S/m | 5.1×105 | 4.7×105 | 4.8×105 | 4.3×105 | 4.2×105 | 1.7×104 |
As can be seen from table 1, the conductivity of the graphene current collector prepared in the embodiment of the present invention is greatly improved.
The conductivity was measured by the following method: the samples were tested for conductivity at room temperature using a D41-11D/ZM model dual electrical four-probe tester. The conductivity can be calculated as γ ═ 1/ρ.
2. Tensile Strength test
The tensile test is carried out on a dynamic mechanical analyzer (DMA Q800/TA), and the graphene current collector prepared in the embodiment of the invention and the graphene current collector prepared in the comparative example are cut into 5 multiplied by 15mm2The rectangular sheet of (a) was subjected to a tensile test.
The test results are given in table 2 below:
as can be seen from table 2, the mechanical strength of the graphene current collector prepared in the embodiment of the present invention is greatly improved.
In addition, the current collectors of five examples and one comparative example were respectively mounted in the target lead-carbon battery to test the cycle life thereof, and the test results are shown in the following table 3:
sample number | Example one | Example two | EXAMPLE III | Example four | EXAMPLE five | Comparative example |
Number of cycles | 25 ten thousand times | 19 ten thousand times | 21 ten thousand times | 22.5 ten thousand times | 23 ten thousand times | 9 ten thousand times |
As can be seen from the above table, the preparation method of the graphene current collector provided by the invention effectively improves the cycle use frequency of the battery, i.e., prolongs the service life of the battery.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (10)
1. The preparation method of the graphene current collector is characterized by comprising the following steps:
(1) mixing graphene, a binder and a solvent to obtain a graphene suspension, wherein the content of graphene in the graphene suspension is 0.005 mg/ml-10 mg/ml;
(2) filtering the graphene suspension in vacuum through a microporous filter membrane, adding a high molecular solution into a precursor filter cake obtained by filtering to obtain a mixed solution, filtering the mixed solution until the mixed solution is completely filtered, and drying the filter cake completely filtered in a drying oven at 50-100 ℃ to obtain a graphene film;
(3) and taking out the graphene film and the microporous filter membrane, and treating at 300-1200 ℃ under a protective atmosphere to obtain the graphene current collector.
2. The method for preparing the graphene current collector as claimed in claim 1, wherein the binder in step (1) is at least one of sodium carboxymethylcellulose, styrene-butadiene rubber, polyvinyl alcohol, polytetrafluoroethylene or polyurethane.
3. The method for preparing the graphene current collector according to claim 1, wherein the solvent in the step (1) is at least one of water, absolute ethyl alcohol, N-dimethylformamide and dimethyl sulfoxide.
4. The method for preparing the graphene current collector as claimed in claim 1, wherein the polymer solution in step (2) is a polyvinyl alcohol solution, a polyvinyl pyrrolidone solution or a polyethylene oxide solution, and the polyvinyl alcohol, the polyvinyl pyrrolidone or the polyethylene oxide accounts for 0.05-10% of the total mass of the whole mixed solution.
5. The preparation method of the graphene current collector according to claim 1, wherein the mass ratio of the graphene to the binder is (1-50): 1, the concentration of the macromolecular solution is 0.5-10%.
6. The preparation method of the graphene current collector according to claim 1, wherein the thickness of the graphene film is 1 μm to 15 μm.
7. The preparation method of the graphene current collector as claimed in claim 1, wherein the protective atmosphere in step (3) is pure argon or an argon/hydrogen mixture.
8. The method for preparing the graphene current collector as claimed in claim 1, wherein the time for processing the graphene and the microporous filter membrane in the step (3) is 30min to 3 h.
9. The method for preparing the graphene current collector as claimed in claim 1, wherein the microporous filter membrane is a mixed fiber membrane, a nylon membrane or a cellulose acetate membrane, and the pore diameter of the micropores is 50nm to 250 nm.
10. The preparation method of the graphene current collector according to claim 1, wherein the graphene suspension is obtained by mixing the graphene, the binder and the solvent in the step (1) and then performing ultrasonic dispersion for 0.5-3 hours.
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CN103427088A (en) * | 2012-05-25 | 2013-12-04 | 海洋王照明科技股份有限公司 | Making method of graphene paper collector |
CN103903877A (en) * | 2012-12-26 | 2014-07-02 | 海洋王照明科技股份有限公司 | Preparation method for graphene/graphene oxide composite current collector |
US20150086881A1 (en) * | 2013-09-23 | 2015-03-26 | Aruna Zhamu | Large-grain graphene thin film current collector and secondary batteries containing same |
CN106025289A (en) * | 2016-05-31 | 2016-10-12 | 宁波墨西科技有限公司 | Preparation method of graphene current collector |
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Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
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CN103427088A (en) * | 2012-05-25 | 2013-12-04 | 海洋王照明科技股份有限公司 | Making method of graphene paper collector |
CN103903877A (en) * | 2012-12-26 | 2014-07-02 | 海洋王照明科技股份有限公司 | Preparation method for graphene/graphene oxide composite current collector |
US20150086881A1 (en) * | 2013-09-23 | 2015-03-26 | Aruna Zhamu | Large-grain graphene thin film current collector and secondary batteries containing same |
CN106025289A (en) * | 2016-05-31 | 2016-10-12 | 宁波墨西科技有限公司 | Preparation method of graphene current collector |
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Application publication date: 20201023 |