CN114220962A - Preparation method of graphene modified lithium material and graphene modified lithium material - Google Patents
Preparation method of graphene modified lithium material and graphene modified lithium material Download PDFInfo
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
- H01M4/381—Alkaline or alkaline earth metals elements
- H01M4/382—Lithium
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/027—Negative electrodes
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- 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
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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Abstract
The invention provides a preparation method of a graphene modified lithium material and the graphene modified lithium material, wherein the preparation method comprises the following steps: the method comprises the steps of stacking a graphene material and a lithium metal sheet, enabling graphene in the graphene material to be in contact with the lithium metal sheet, combining the graphene with the lithium metal sheet in a transfer printing mode, and modifying the lithium metal sheet, wherein the thickness of the graphene in the graphene material is 0.2-5 nm. By forming a layer of ultrathin uniform graphene film on the surface of the lithium metal sheet, the direct contact between the electrolyte and the lithium metal sheet is effectively avoided, and the effect of forming a passivation film on the lithium metal sheet is achieved without adding a binder. The modification process does not affect the conductivity and uniformity of the lithium metal sheet, the thickness of the graphene modification layer in the graphene modified lithium material is very small, the energy density loss of the battery is avoided, the formation of lithium dendrites can be inhibited, and the cycling stability and the electrochemical performance of the lithium metal sheet as a battery cathode material are improved.
Description
Technical Field
The invention relates to the technical field of metal material modification, in particular to a preparation method of a graphene modified lithium material and the graphene modified lithium material.
Background
Lithium ion batteries have been widely used in the fields of portable electronic devices and electric vehicles, and become an indispensable energy storage device in daily life of people. However, due to the limitation of the energy density of the lithium ion battery, the service time of the portable electronic device, the driving mileage of the electric vehicle, and the like still cannot meet the actual demands of people. At present, the energy density of a lithium ion battery system taking graphite as a negative electrode is close to the theoretical capacity, and the theoretical specific capacity of the graphite negative electrode is only 372mAh/g, so that the development of a high-specific-energy battery negative electrode material becomes urgent. The theoretical specific capacity of the metallic lithium is as high as 3860mAh/g, the metallic lithium is one of the electrode materials with the highest mass specific energy of the existing known materials, and the metallic lithium cathode has the lowest density of the metal group (0.59 g/cm)3) And the lowest electrochemical potential (-3.04V), are considered to be the most potential anode materials. However, the lithium metal negative electrode has dendrite formation during charge and discharge cycles, which causes the generation of "dead lithium", damages a solid electrolyte film (SEI film), not only reduces the cycle efficiency of the battery, but also punctures a diaphragm, and causes serious potential safety hazards. Furthermore, the lithium metal also undergoes a severe volume expansion during the charge-discharge cycle, which also results in instability of the lithium metal negative electrode, causing safety problems. Under the research of researchers, the safety and the cycle performance of the lithium metal anode material are greatly improved, and the lithium metal anode material mainly comprises an optimized electrolyte,Regulating and controlling the current collector structure and modifying the lithium negative electrode. The electrolyte is optimized by mainly adjusting the solvent of the electrolyte or adding an additive to improve the physical and chemical properties of the SEI film, so that the performance of the battery is improved, but the method can influence other performances of the battery, such as an electrochemical window, specific discharge capacity and the like; the current collector structure is regulated and controlled mainly by coating the surface of the current collector or preparing a three-dimensional porous current collector, so that the growth of lithium dendrites is relieved, but the method is difficult to realize large-scale application, so that the direct modification of the lithium negative electrode is the most direct and feasible way at present.
At present, the direct modified lithium negative electrode mainly comprises three modes of surface coating of a metal lithium negative electrode, preparation of a composite metal lithium negative electrode and preparation of a metal lithium alloy. The surface of the lithium metal cathode is coated by magnetron sputtering or plasma-assisted electron beam evaporation, and the like, so that the formed film is compact and uniform, but the method is difficult to use on a large scale; the composite metal lithium electrode generally adopts a melting method to pour metal lithium into a host material with a 3D or other structure, but the poured metal lithium by the method is uneven in distribution, poor in consistency and high in requirement on the host material; the lithium alloy electrode uses lithium alloy to replace pure metal lithium negative electrode material, reduces the reaction activity of lithium and electrolyte, improves the interface stability of electrolysis/electrolyte, but the lithium alloy reduces the voltage of the battery while reducing the activity of metal lithium, and the introduction of the alloy material also reduces the specific mass capacity of the electrode.
Disclosure of Invention
Accordingly, in order to reduce the influence on the modified lithium material and improve the battery performance of the modified lithium material as an electrode material, it is necessary to provide a method for preparing a graphene-modified lithium material and a graphene-modified lithium material.
The invention provides a preparation method of a graphene modified lithium material, which comprises the following steps:
the method comprises the steps of stacking a graphene material and a lithium metal sheet, enabling graphene in the graphene material to be in contact with the lithium metal sheet, combining the graphene with the lithium metal sheet in a transfer printing mode, and modifying the lithium metal sheet, wherein the thickness of the graphene in the graphene material is 0.2-5 nanometers.
In one embodiment, the graphene has a thickness of 0.4 nm to 4 nm.
In one embodiment, the graphene material is graphene prepared by chemical vapor deposition attached to a base film selected from at least one of a polyethylene terephthalate film and a thermal release tape film.
In one embodiment, the atomic percentage of the doping atoms in the graphene is 0% to 40%; and/or
The doping atoms are selected from at least one of nitrogen, phosphorus, boron, sulfur and oxygen atoms.
In one embodiment, the transfer is by a method selected from the group consisting of thermal transfer, adhesive transfer, solvent transfer, roll transfer, and electrostatic transfer.
In one embodiment, the transfer printing mode is roll-in transfer printing, the roll-in times are 8-20 times, the roll-in speed is 0-20 mm/s, and the roll-in temperature is 50-80 ℃.
Further, the invention also provides a graphene modified lithium material prepared by the preparation method of the graphene modified lithium material.
It can be understood that the present invention also provides the use of the graphene-modified lithium material described above in the preparation of an electrode material for a lithium battery.
The invention provides a lithium battery, which comprises electrolyte, a positive pole piece, a negative pole piece and a battery diaphragm, wherein the battery diaphragm is positioned between the positive pole piece and the negative pole piece, and the positive pole piece, the negative pole piece and the battery diaphragm are soaked in the electrolyte, wherein the negative pole piece is the graphene modified lithium material.
Furthermore, the invention also provides an electric product, and the power supply device of the electric product is the lithium battery.
The ultrathin graphene material is contacted with the lithium metal sheet and combined and modified in a transfer printing mode, so that an ultrathin uniform graphene film is formed on the surface of the lithium metal sheet, direct contact between electrolyte and the lithium metal sheet is effectively avoided, and the effect of forming a passivation film on the lithium metal sheet is achieved without adding a binder. In addition, the modification process does not influence the conductivity and uniformity of the lithium metal sheet, the thickness of a graphene modification layer in the graphene modified lithium material is very small, the energy density loss of the battery is avoided, the formation of lithium dendrites can be inhibited, and the cycling stability and the electrochemical performance of the lithium metal sheet as a battery cathode material are improved.
Drawings
Fig. 1 is a diagram of a raw material lithium metal material used in the preparation method of the graphene-modified lithium material in example 1;
FIG. 2 is a schematic diagram of a graphene material grown on a polyethylene terephthalate film by chemical vapor deposition using the raw materials used in the method for preparing the graphene-modified lithium material of example 1;
fig. 3 is a voltage-time diagram in an electrochemical test of a method for preparing a graphene-modified lithium material and a pure lithium material according to example 1;
fig. 4 is a graph of cycle performance in electrochemical tests of the method for preparing graphene-modified lithium material and pure lithium material of example 1;
fig. 5 is an impedance diagram in an electrochemical test of a method for preparing a graphene-modified lithium material and a pure lithium material according to example 1;
fig. 6 is a graph of cycle performance in electrochemical tests of graphene-modified lithium materials of example 1 and comparative example 1;
fig. 7 is an impedance diagram in an electrochemical test of graphene-modified lithium materials of example 1 and comparative example 2.
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the invention, "a plurality" means at least two, e.g., two, three, etc., unless explicitly specified otherwise. In the description of the present invention, "a plurality" means at least one, e.g., one, two, etc., unless specifically limited otherwise.
The words "preferably," "more preferably," and the like, in the present disclosure mean embodiments of the disclosure that may, in some instances, provide certain benefits. However, other embodiments may be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention.
When a range of values is disclosed herein, the range is considered to be continuous and includes both the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values of the range is included. Further, when multiple range-describing features or characteristics are provided, the ranges may be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein.
It should be noted that in the description of the present invention, for the terms of orientation, there are terms such as "central", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicating the orientation and positional relationship based on the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and should not be construed as limiting the specific scope of the present invention.
In describing positional relationships, unless otherwise specified, when an element such as a layer, film or substrate is referred to as being "on" another layer, it can be directly on the other layer or intervening layers may also be present. Further, when a layer is referred to as being "under" another layer, it can be directly under, or one or more intervening layers may also be present. It will also be understood that when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.
Where the terms "comprising," "having," and "including" are used herein, it is intended to cover a non-exclusive inclusion, as another element may be added, unless an explicit limitation is used, such as "only," "consisting of … …," etc.
Unless mentioned to the contrary, terms in the singular may include the plural and are not to be construed as being one in number.
Further, the drawings are not drawn to a 1:1 scale, and the relative sizes of the elements in the drawings are drawn only by way of example to facilitate understanding of the invention, but are not necessarily drawn to true scale, and the scale in the drawings does not constitute a limitation of the invention. It will be understood that when an element is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
The invention provides a preparation method of a graphene modified lithium material, which comprises the following steps: the method comprises the steps of stacking a graphene material and a lithium metal sheet, enabling graphene in the graphene material to be in contact with the lithium metal sheet, combining the graphene with the lithium metal sheet in a transfer printing mode, and modifying the lithium metal sheet, wherein the thickness of the graphene in the graphene material is 0.2-5 nanometers.
In one specific example, the thickness of the graphene is preferably 0.4 to 4 nanometers.
It is understood that the graphene is few-layer graphene, and the thickness thereof may be, but is not limited to, 0.4 nm, 0.8 nm, 1.2 nm, 1.6 nm, 2nm, 2.4 nm, 2.8 nm, 3.2 nm, 3.6 nm, or 4 nm.
The ultrathin graphene material is contacted with the lithium metal sheet and combined and modified in a transfer printing mode, so that an ultrathin uniform graphene film is formed on the surface of the lithium metal sheet, direct contact between electrolyte and the lithium metal sheet is effectively avoided, and the effect of forming a passivation film on the lithium metal sheet is achieved without adding a binder. In addition, the modification process does not influence the conductivity and uniformity of the lithium metal sheet, the thickness of a graphene modification layer in the graphene modified lithium material is very small, the energy density loss of the battery is avoided, the formation of lithium dendrites can be inhibited, and the cycling stability and the electrochemical performance of the lithium metal sheet as a battery cathode material are improved.
In one particular example, the graphene material is graphene prepared by chemical vapor deposition attached to a base film.
It is understood that the base film is selected from at least one of a polyethylene terephthalate film and a heat release tape film.
It can be understood that the base film is only a carrier of graphene, the base film is not modified with graphene to the lithium metal sheet, and only graphene on the base film is transferred to the lithium metal sheet during the transfer process.
In a specific example, the atomic percentage of the doping atoms in the graphene is 0% to 40%.
Specifically, the atomic percentage of the doping atoms may be, but is not limited to, 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, or 40%.
In a specific example, the doping atoms in the graphene are selected from at least one of nitrogen, phosphorus, boron, sulfur, and oxygen atoms.
Heteroatom doping of graphene can change the electronic properties of graphene to a great extent, such as: the density of electron cloud, chemical reaction activity and the like, and simultaneously, the electrostatic repulsion between graphene sheets can be increased, the aggregation of the graphene sheets is effectively reduced, and the application range of the graphene material is extended.
In general, heteroatom-doped graphene includes physical doping and chemical doping, wherein physical doping of graphene generally refers to the recombination of graphene with other nanomaterials, and stacking thereof is prevented by introducing other nanomaterials between graphene sheets, and the chemical doping types for graphene can be divided into two types: one is surface transfer doping, which occurs between additional functional groups of graphene sheets, similar to the surface functionalization of graphene, resulting in n-type doping or p-type doping, depending on the nature of the functional group, electron donor or electron acceptor; the other doping is substitution type doping, and is realized by substituting carbon atoms in a graphene framework by heteroatoms through certain external force, and the physical and chemical properties of graphene can be changed to a greater extent through the doping.
In one specific example, the transfer is by a method selected from the group consisting of thermal transfer, adhesive transfer, solvent transfer, roll transfer, and electrostatic transfer.
In a specific example, the transfer mode is roll transfer, the number of roll presses is 8-20, the roll press speed is 0-20 mm/s, and the roll press temperature is 50-80 ℃.
Preferably, the number of rolling times may be, but is not limited to, 10 to 20, and specifically, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20.
Further, the rolling temperature may be, but not limited to, 58 ℃ to 78 ℃, specifically 58 ℃, 60 ℃, 62 ℃, 64 ℃, 66 ℃, 68 ℃, 70 ℃, 72 ℃, 74 ℃, 76 ℃ or 78 ℃.
Further, the rolling speed may be, but not limited to, 4mm/s to 12mm/s, and specifically, 4mm/s, 5mm/s, 6mm/s, 8mm/s, 10mm/s or 12 mm/s.
In general, the initial thickness of the metal lithium material is 1cm, and the graphene-modified lithium material is finally rolled to a thickness of 0.1mm to 0.5 mm.
That is, the thickness of the graphene-modified lithium material is preferably 0.15mm to 0.45mm, and may be, but is not limited to, 0.15mm, 0.18mm, 0.21mm, 0.24mm, 0.27mm, 0.3mm, 0.33mm, 0.36mm, 0.39mm, 0.42mm, or 0.45 mm.
In one specific example, the transfer is performed in an inert atmosphere.
The invention also provides a graphene modified lithium material prepared by the preparation method of the graphene modified lithium material.
The ultrathin graphene material is contacted with the lithium metal sheet and combined and modified in a transfer printing mode, so that an ultrathin uniform graphene film is formed on the surface of the lithium metal sheet, direct contact between electrolyte and the lithium metal sheet is effectively avoided, and the effect of forming a passivation film on the lithium metal sheet is achieved without adding a binder. In addition, the modification process does not influence the conductivity and uniformity of the lithium metal sheet, the thickness of a graphene modification layer in the graphene modified lithium material is very small, the energy density loss of the battery is avoided, the formation of lithium dendrites can be inhibited, and the cycling stability and the electrochemical performance of the lithium metal sheet as a battery cathode material are improved.
It can be understood that the present invention also provides the use of the graphene-modified lithium material described above in the preparation of an electrode material for a lithium battery.
The invention provides a lithium battery, which comprises electrolyte, a positive pole piece, a negative pole piece and a battery diaphragm, wherein the battery diaphragm is positioned between the positive pole piece and the negative pole piece, and the positive pole piece, the negative pole piece and the battery diaphragm are soaked in the electrolyte, wherein the negative pole piece is the graphene modified lithium material.
Furthermore, the invention also provides an electric product, and the power supply device of the electric product is the lithium battery.
The following specific examples are provided to further explain the method for preparing the graphene-modified lithium material and the graphene-modified lithium material of the present invention in detail. It is to be understood that the starting materials used in the following embodiments are all commercially available, unless otherwise specified.
The following examples and comparative examples have the CAS number for the graphene material grown on polyethylene terephthalate film: 7440-44-0, cat 100159 monolayer, 5cm by 5cm in area, cat 100160 bilayer 5cm by 5cm, cat 100161 three to five layers 5cm by 5cm in area.
Example 1
The embodiment provides a graphene-modified lithium material, which is a material diagram of a lithium metal sheet used as a raw material shown in fig. 1, and is a material diagram of a graphene material grown on a polyethylene terephthalate film in a chemical vapor deposition manner shown in fig. 2, wherein the graphene is undoped graphene, and the thickness of the graphene is 0.35 nm. The preparation method of the graphene modified lithium material comprises the specific steps of contacting one side, with graphene, of the graphene material shown in fig. 2 with a metal lithium material shown in fig. 1, in an argon atmosphere, in a glove box, setting the temperature of a roller press to be 60 ℃ and the rolling speed to be 10mm/s, performing rolling transfer printing on the graphene material and the metal lithium material by using the pressure of the roller press, passing through a roller for 12 times, transferring the graphene film on the polyethylene terephthalate film to the surface of a metal lithium sheet to prepare the graphene modified lithium material, and finally obtaining the graphene modified metal lithium material with the thickness of 0.42 mm.
Example 2
The embodiment provides a graphene modified lithium material, wherein the lithium material is a lithium metal sheet, and the graphene material is a graphene material grown on a thermal release tape film in a chemical vapor deposition manner, wherein the graphene is undoped graphene, and the thickness of the graphene is 1.75 nm. The preparation method of the graphene modified lithium material comprises the steps of contacting one side of the graphene material, on which graphene grows, with a lithium metal sheet, setting the temperature of a roller press to be 75 ℃ and the rolling speed to be 5mm/s in a glove box under the argon atmosphere, carrying out rolling transfer printing on the graphene material and the lithium metal sheet by using the pressure of the roller press, passing through a roller for 20 times, and transferring the graphene film on the polyethylene terephthalate film to the surface of the metal lithium sheet to prepare the graphene modified lithium material, so that the graphene modified lithium metal material with the thickness of 0.18mm is obtained.
Comparative example 1
The comparative example provides a graphene powder coated modified lithium metal material, and the modified slurry is prepared by mixing the following raw materials in parts by weight: graphene powder: 80% of binder polyvinylidene chloride: 1%, solvent N-methylpyrrolidone: 19 percent. And coating the modified slurry on the surface of the lithium metal in a coating mode, and drying to assemble the button battery.
Comparative example 2
This comparative example provides a graphene-modified metallic lithium material, which is different from example 1 in that it is rolled only 5 times during the preparation under otherwise the same conditions.
Performance testing and results analysis
The assembled batteries are button batteries, lithium cobaltate is used as a positive electrode, metallic lithium or graphene modified metallic lithium materials are used as a negative electrode, commercial celgard2400 is used as a diaphragm, and lithium hexafluorophosphate electrolyte is used as the electrolyte (the formula is 1.0M LiPF6, EC: DMC: EMC ═ 1:1: 1).
The charge and discharge performance test is carried out under the charge and discharge multiplying power of 1C, the electrochemical impedance test frequency is 100 mHz-0.1 MHz, and the amplitude is 5 mV.
A voltage-time diagram, a cycle performance diagram, and an impedance diagram of the graphene-modified lithium material and pure lithium provided in example 1 after being used as electrode materials and subjected to electrochemical tests are respectively shown in fig. 3, fig. 4, and fig. 5.
The charging and discharging tests of the battery are performed by assembling the graphene modified lithium material in the comparative example 1 and the graphene modified lithium material in the example 1 into the button battery, and the result is shown in fig. 6, although the stability of the graphene powder modified metal lithium material in the comparative example 1 to the metal lithium is improved, the problem of capacity attenuation still occurs as the charging and discharging time is increased. This is probably because the graphene powder coating is too thick, which hinders the deintercalation of metallic lithium, slows down the kinetics of the electrochemical reaction, and causes capacity loss. However, in example 1, a few-layer graphene-modified metallic lithium was used, and the thickness of the graphene layer was about 0.35nm, so that the deintercalation of metallic lithium was not restricted, and stable and efficient charge and discharge could be maintained over a long cycle.
Comparative example 2 and the graphene modified lithium metal material passing through the roller for 12 times in example 1 are respectively assembled into a button cell, and an electrochemical impedance test is performed, wherein the experimental result is shown in fig. 7. As a result, it was found that R of graphene-modified metallic lithium in comparative example 2 was rolled 5 timesSEIGraphene modified lithium metal, R, much greater than example 1, rolled 12 timesSEINamely, the resistance of lithium ions diffusing and transferring through the SEI film is related to the diffusion and transfer of the lithium ions, the interface bonding between graphene and metal lithium is better when the number of times of passing through a roller is larger in a certain range, and R is higherSEIThe smaller the size, the faster the diffusion and migration of lithium ions, and the better the electrochemical performance.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, so as to understand the technical solutions of the present invention specifically and in detail, but not to be understood as the limitation of the protection scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. It should be understood that the technical solutions provided by the present invention and obtained by logical analysis, reasoning or limited experiments by those skilled in the art are all within the scope of the appended claims. Therefore, the protection scope of the patent of the present invention shall be subject to the content of the appended claims, and the description and the attached drawings can be used for explaining the content of the claims.
Claims (10)
1. A preparation method of a graphene modified lithium material is characterized by comprising the following steps:
the method comprises the steps of stacking a graphene material and a lithium metal sheet, enabling graphene in the graphene material to be in contact with the lithium metal sheet, combining the graphene with the lithium metal sheet in a transfer printing mode, and modifying the lithium metal sheet, wherein the thickness of the graphene in the graphene material is 0.2-5 nanometers.
2. The method of preparing a graphene-modified lithium material according to claim 1, wherein the graphene has a thickness of 0.4 nm to 4 nm.
3. The method of preparing a graphene-modified lithium material according to claim 1, wherein the graphene material is graphene prepared by chemical vapor deposition attached to a base film selected from at least one of a polyethylene terephthalate film and a thermal release tape film.
4. The method for preparing the graphene-modified lithium material according to claim 1, wherein the atomic percentage of the doping atoms in the graphene is 0% to 40%; and/or
The doping atoms are selected from at least one of nitrogen, phosphorus, boron, sulfur and oxygen atoms.
5. The method for preparing the graphene-modified lithium material according to any one of claims 1 to 4, wherein the transfer printing is performed by a method selected from thermal transfer printing, adhesive transfer printing, solvent transfer printing, roll transfer printing or electrostatic transfer printing.
6. The method for preparing the graphene-modified lithium material according to claim 5, wherein the transfer mode is roll transfer, the number of roll passes is 8-20, the roll speed is 0-20 mm/s, and the roll temperature is 50-80 ℃.
7. A graphene-modified lithium material, characterized by being prepared by the method for preparing a graphene-modified lithium material according to any one of claims 1 to 6.
8. Use of the graphene-modified lithium material of claim 7 for the preparation of an electrode material for a lithium battery.
9. A lithium battery is characterized by comprising electrolyte, a positive pole piece, a negative pole piece and a battery diaphragm, wherein the battery diaphragm is positioned between the positive pole piece and the negative pole piece, and the positive pole piece, the negative pole piece and the battery diaphragm are soaked in the electrolyte, wherein the negative pole piece is the graphene modified lithium material according to claim 7.
10. An electric product characterized in that its power supply means is a lithium battery as claimed in claim 9.
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| CN117030410B (en) * | 2023-10-10 | 2023-12-15 | 北京科技大学 | Preparation method of ultrathin metal material metallographic sample |
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