Graphene and preparation method thereof, and graphene slurry

Abstract

The invention provides graphene, a preparation method thereof and graphene slurry. The preparation method of the graphene comprises the following steps: obtaining graphite; carrying out acid treatment on the graphite to disperse the graphite in concentrated sulfuric acid to obtain a graphite dispersion liquid; carrying out oxidation treatment on graphite to enable the graphite dispersion liquid to be sequentially mixed with potassium permanganate and hydrogen peroxide for reaction, and carrying out suction filtration to obtain graphene oxide; carrying out solvation treatment on the graphene oxide, and adding the graphene oxide into a strong-polarity aprotic solvent to carry out purification modification, so as to obtain pretreated graphene oxide; and carrying out reduction operation on the pretreated graphene oxide. According to the preparation method of the graphene, the preparation of the graphene with relatively high conductivity and relatively good dispersion stability can be realized.

Description

Technical Field

[0001] This invention relates to the field of graphene materials technology, and in particular to a graphene, a method for preparing the graphene, and a graphene slurry. Background Technology

[0002] Since its initial discovery, graphene's excellent properties and wide range of applications have attracted a large number of researchers to focus on and continuously study it. For example, patent applications CN201611148006.9 and CN201710461328.7 both involve using concentrated sulfuric acid and potassium permanganate to introduce oxygen-containing groups such as carboxyl and hydroxyl groups into graphite. Then, hydrogen peroxide is used to reduce the residual oxidant in the graphite, yielding graphene oxide. Ammonia and hydrazine hydrate are then used to further reduce the graphene oxide for industrial production. However, in industrial graphene production, the reduction of graphene oxide retains too many oxygen-containing functional groups to achieve dispersion stability, but this results in poor conductivity. Conversely, the reduction of graphene oxide in industrial graphene production removes more oxygen-containing functional groups to achieve higher conductivity, which affects the dispersion stability of the final graphene. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide graphene with high conductivity and good dispersion stability, its preparation method, and graphene slurry.

[0004] The objective of this invention is achieved through the following technical solution: A method for preparing graphene includes the following steps: Obtain graphite; The graphite is subjected to acid treatment to disperse it in concentrated sulfuric acid, thereby obtaining a graphite dispersion. The graphite is subjected to oxidation treatment so that the graphite dispersion is mixed and reacted sequentially with potassium permanganate and hydrogen peroxide, and then filtered to obtain graphene oxide. The graphene oxide is subjected to solvation treatment, in which the graphene oxide is added to a strongly polar aprotic solvent for purification and modification to obtain pretreated graphene oxide. The pretreated graphene oxide is then reduced.

[0005] In one embodiment, the strongly polar aprotic solvent is at least one selected from N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolinone, and sulfolane.

[0006] In one embodiment, the mass ratio of the graphene oxide to the strongly polar aprotic solvent is 1:(120~200).

[0007] In one embodiment, the graphene oxide is subjected to ultrasonic solvation treatment to purify and modify the graphene oxide by adding it to the strongly polar aprotic solvent under ultrasonic conditions.

[0008] In one embodiment, the graphene oxide is subjected to ultrasonic solvation treatment at an ultrasonic frequency of 20 kHz to 200 kHz.

[0009] In one embodiment, the graphene oxide is subjected to ultrasonic solvation treatment for 1.5 h to 2.5 h.

[0010] In one embodiment, the pretreated graphene oxide is reduced, including the following steps: The pretreated graphene oxide was subjected to pH adjustment treatment with ammonia water to make the pH of the pretreated graphene oxide 8-9. The pretreated graphene oxide was subjected to oxime reduction treatment using hydroxylamine hydrochloride; The pretreated graphene oxide was reduced using hydrazine hydrate.

[0011] In one embodiment, after the step of reducing the pretreated graphene oxide, the method for preparing the graphene further includes the following steps: The pretreated graphene oxide was mixed with protonated polyaniline.

[0012] In one embodiment, the pretreated graphene oxide is mixed with protonated polyaniline, and the specific operation is as follows: Protonated polyaniline was dissolved in water to prepare a protonated polyaniline solution, and the pretreated graphene oxide was added dropwise to the protonated polyaniline solution and stirred to mix.

[0013] A type of graphene is prepared by the graphene preparation method described in any of the above embodiments.

[0014] A graphene slurry comprising a dispersant, a solvent, and graphene as described in any of the above embodiments.

[0015] In one embodiment, the dispersant is at least one of ethyl cellulose, hydroxypropyl cellulose, and fatty alcohol polyoxyethylene ether.

[0016] In one embodiment, the solvent is at least one selected from terpineol, dibutyl phthalate, butyl carbitol acetate, and N,N'-dimethylformamide.

[0017] In one embodiment, the graphene slurry comprises the following components in parts by weight: 5%~10% dispersant; 80%~90% solvent; and 5%~10% graphene.

[0018] Compared with the prior art, the present invention has at least the following advantages: The graphene preparation method of the present invention involves acid treatment of graphite followed by oxidation treatment, resulting in graphene oxide with a large interlayer spacing. Further, the graphene oxide is solvated to achieve purification, impurity removal, interlayer intercalation, and interface modification. This method effectively ensures that the graphene oxide maintains good dispersion stability even at high reduction levels, while also guaranteeing the high conductivity of the obtained graphene. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a scanning electron microscope image of the graphene obtained in Example 5; Figure 2 This is a scanning electron microscope image of the graphene obtained in Comparative Example 1. Detailed Implementation

[0021] The present application will be further described in detail below with reference to the embodiments and examples. It should be understood that these embodiments and examples are for illustrative purposes only and are not intended to limit the scope of the present application. The purpose of providing these embodiments and examples is to enable a more thorough and comprehensive understanding of the disclosure of the present application. It should also be understood that the present application can be implemented in many different forms and is not limited to the embodiments and examples described herein. Those skilled in the art can make various modifications or alterations without departing from the spirit of the present application, and the equivalent forms obtained also fall within the protection scope of the present application. Furthermore, numerous specific details are set forth in the following description to provide a fuller understanding of the present application. It should be understood that the present application can be implemented without one or more of these details.

[0022] Unless otherwise defined, 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 pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0024] In this invention, numerical intervals (i.e., numerical ranges) are involved. Unless otherwise specified, the selected numerical distributions within the aforementioned numerical intervals are considered continuous, and include the two endpoints (i.e., the minimum and maximum values) of the numerical range, as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints. In this document, this is equivalent to directly listing every integer. For example, if t is an integer selected from 1 to 10, it means that t is any integer selected from the group of integers consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. Furthermore, when multiple ranges are provided to describe features or characteristics, these ranges can be merged. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0025] Unless otherwise specified, the temperature parameters in this invention can be either constant temperature treatment or vary within a certain temperature range. It should be understood that constant temperature treatment allows temperature fluctuations within the precision range controlled by the instrument. Fluctuations are permitted within ranges such as ±5℃, ±4℃, ±3℃, ±2℃, and ±1℃.

[0026] This application provides a method for preparing graphene. The method for preparing graphene includes the following steps: obtaining graphite; acid-treating the graphite to disperse it in concentrated sulfuric acid to obtain a graphite dispersion; oxidizing the graphite to react the graphite dispersion with potassium permanganate and hydrogen peroxide in sequence, and then filtering to obtain graphene oxide; solvating the graphene oxide by adding it to a strongly polar aprotic solvent for purification and modification to obtain pretreated graphene oxide; and reducing the pretreated graphene oxide.

[0027] The above-described method for preparing graphene involves acid treatment of graphite followed by oxidation treatment, resulting in graphene oxide with a large interlayer spacing. Further, solvation treatment of the graphene oxide is performed to purify and remove impurities, perform interlayer intercalation and interface modification, and achieve good dispersion stability of graphene oxide even at high reduction degrees, while ensuring the high conductivity of the obtained graphene.

[0028] To better understand the graphene preparation method of this application, the following further explanation is provided: One embodiment of the graphene preparation method includes the following steps: S100, Obtain graphite. It can be understood that the graphite is expanded graphite.

[0029] S200. Graphite is acid-treated to disperse it in concentrated sulfuric acid, resulting in a graphite dispersion. It can be understood that the sulfuric acid embeds into the interlayer spaces of the graphite, disrupting the van der Waals forces and widening the interlayer spacing, thus providing a basis for the subsequent entry of oxidants into the graphite interlayer spaces.

[0030] S300: Graphite is oxidized by sequentially mixing and reacting a graphite dispersion with potassium permanganate and hydrogen peroxide, followed by filtration to obtain graphene oxide. It can be understood that the strong acid environment formed by sulfuric acid enhances the oxidizing power of potassium permanganate. Simultaneously, sulfuric acid, as a solvent, promotes the expansion of graphite intercalation by potassium permanganate into the graphite interlayers, enabling selective oxidation of carbon atoms within the intercalated graphite layers, thus achieving deep oxidation of graphite. Hydrogen peroxide is used to terminate the oxidation of graphite by potassium permanganate. Furthermore, the oxygen bubbles generated by the decomposition of hydrogen peroxide also have a physical exfoliating effect on the graphite, further expanding the interlayer spacing.

[0031] S400. Solventization treatment of graphene oxide involves adding a strongly polar aprotic solvent to purify and modify the graphene oxide, resulting in pretreated graphene oxide. It is understood that the graphene oxide obtained after filtration easily retains inorganic impurities such as sulfates, sulfuric acid, hydrogen ions, incompletely removed manganese oxides, and trace amounts of manganese salts after hydrogen peroxide reduction. The strongly polar aprotic solvent is miscible with water and has a certain solubility or affinity for inorganic impurities. Therefore, the addition of the strongly polar aprotic solvent allows for the elution of inorganic impurities adsorbed on the surface and between layers of graphene oxide, reducing the impact of impurity residues on the subsequent dispersibility and conductivity of graphene oxide. Furthermore, the strongly polar aprotic solvent has good solubility for organic oxygen-containing compounds, which can dissolve and elute low-molecular-weight carbon oxide fragments generated by the strong oxidation of graphite in potassium permanganate, mitigating the problem of reduced graphene oxide purity caused by carbon fragment adsorption on the graphene oxide. This process effectively ensures the conductivity of the graphene. Furthermore, the highly polar aprotic solvent possesses highly polar groups that can bind to the oxygen-containing functional groups on graphene oxide via hydrogen bonds, disrupting the van der Waals forces between graphene oxide layers and further increasing the interlayer spacing. Additionally, the highly polar aprotic solvent forms an organic interface layer on the graphene oxide, which not only improves the problem of graphene layer agglomeration due to attraction during subsequent drying but also enhances the affinity between graphene oxide and organic solvents. This allows graphene oxide to be stably dispersed in organic or inorganic solvents even at high reduction levels, providing an interfacial bonding basis for the subsequent preparation of graphene slurry, thus ensuring the uniformity and stability of the graphene slurry dispersion.

[0032] S500, Reduce the pretreated graphene oxide. This process involves reducing the pretreated graphene oxide to obtain graphene, achieving good dispersion stability of the graphene oxide even at high reduction degrees, while ensuring the high conductivity of the resulting graphene.

[0033] The above-described method for preparing graphene involves acid treatment of graphite followed by oxidation treatment, resulting in graphene oxide with a large interlayer spacing. Further, solvation treatment of the graphene oxide is performed to purify and remove impurities, perform interlayer intercalation and interface modification, and achieve good dispersion stability of graphene oxide even at high reduction degrees, while ensuring the high conductivity of the obtained graphene.

[0034] In one embodiment, the graphite is acid-treated with a mass ratio of graphite to 98% concentrated sulfuric acid of 1:(15~25). Further, the graphite is oxidized with a mass ratio of graphite to potassium permanganate of 1:(2.5~3.0). Further, the graphite is acid-treated by adding concentrated sulfuric acid to the graphene, reacting, and then cooling to room temperature. Further, concentrated sulfuric acid is added to the graphene at a reaction temperature of 90°C. Further, the reaction time is 3.5h~4.5h.

[0035] In one embodiment, the graphite is oxidized, comprising some or all of the following steps: Potassium permanganate was added to the graphite dispersion for mixing and dispersion. Further, potassium permanganate was added to the graphite dispersion for mixing and dispersion at a stirring speed of 300 r / min. Further, potassium permanganate was added to the graphite dispersion for mixing and dispersion for 5-10 hours.

[0036] Further, the graphite dispersion after mixing and dispersion treatment is added dropwise to hydrogen peroxide and stirred for dispersion treatment. Further, the concentration of hydrogen peroxide is 0.5%~27.5%. Further, the volume ratio of the graphite dispersion after mixing and dispersion treatment to hydrogen peroxide is 10:1. Further, the stirring time is 2h~4h.

[0037] Further, the graphite dispersion after stirring and dispersion treatment is washed. Further, the graphite dispersion after stirring and dispersion treatment is washed with deionized water. Further, the graphite dispersion after stirring and dispersion treatment is washed 3 to 5 times.

[0038] In one embodiment, potassium permanganate is added to a graphite dispersion for mixing and dispersion treatment, including some or all of the following steps: Potassium permanganate was slowly added to the graphite dispersion at a temperature of 0℃~5℃. Furthermore, the stirring time was 2~4 hours. Furthermore, the potassium permanganate was added at a rate of 0.1 g / min.

[0039] Furthermore, the graphite dispersion was stirred at a temperature of 30℃~38℃. The stirring time was further 1~2 hours.

[0040] Further, deionized water was added to the graphite dispersion, and the temperature was raised to 95℃~102℃, and the graphite dispersion was stirred. Further, the stirring time was 2h~4h. Further, the mass ratio of graphite to deionized water was 1:(45~55).

[0041] It is understandable that potassium permanganate is slowly added to graphite, and the temperature is maintained between 0℃ and 5℃. During this mild stage, the reaction mainly involves the formation of intercalation compounds and mild oxidation. In this process, concentrated sulfuric acid molecules first intercalate between the graphite layers to form graphite-sulfuric acid intercalation compounds, such as C8H2SO4. Under acidic conditions, potassium permanganate is reduced to Mn. 3+ The active carbon atoms at the edges and defects of the graphite are oxidized, introducing a small amount of hydroxyl and epoxy groups; then, the temperature is raised to 30℃~38℃ and stirred continuously; this stage is the core oxidation step, Mn 3+ As an intermediate oxidant, it continuously oxidizes the sp within the graphite layer. 2 Carbon is oxidized, introducing a large number of epoxy and hydroxyl groups onto the graphite basal surface, thus making graphite sp... 2 The conjugated structure is disrupted, and the interlayer spacing further increases to 0.6–0.7 nm. The reduction products of potassium permanganate are mainly MnO2, with some Mn. 2+ Next, deionized water is slowly added to the system while the temperature is raised to 95℃~102℃. During this stage, hydrolysis and carboxyl group introduction occur. Sulfate and water molecules between graphite layers are hydrolyzed, and hydroxyl groups at the graphite edges are further oxidized to carboxyl groups (-COOH). The introduction of carboxyl groups makes the oxidized graphite water-soluble and dispersible. Excess potassium permanganate reacts with water to generate MnO2 and O2, which better achieves the high oxidation of graphite and the effective improvement of interlayer spacing.

[0042] In one embodiment, the strongly polar aprotic solvent is at least one selected from N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolinone, and sulfolane. Further, the mass ratio of graphene oxide to the strongly polar aprotic solvent is 1:(120~200). Further, the mass ratio of graphene oxide to N,N-dimethylformamide is 1:158. Further, the strongly polar aprotic solvent is N,N-dimethylformamide.

[0043] In one embodiment, graphene oxide is subjected to ultrasonic solvation treatment to purify and modify the graphene oxide by adding it to a strongly polar aprotic solvent under ultrasonic conditions.

[0044] In one embodiment, graphene oxide is subjected to ultrasonic solvation treatment at an ultrasonic frequency of 20 kHz to 200 kHz. Further, the graphene oxide is subjected to ultrasonic solvation treatment for 1.5 h to 2.5 h.

[0045] In one embodiment, the ultrasonic solvation treatment of graphene oxide includes at least the following steps: S410. Under medium-frequency ultrasonic conditions, graphene oxide is added to a strongly polar aprotic solvent for a first ultrasonic treatment to obtain an ultrasonic dispersion. Further, the ultrasonic frequency is 60kHz~100kHz. Further, the ultrasonic time is 35min~45min.

[0046] S420. The ultrasonic dispersion is subjected to a second ultrasonic treatment under low-frequency ultrasonic conditions. Further, the ultrasonic frequency is 20kHz~40kHz. Further, the ultrasonic time is 25min~35min.

[0047] S430. Under high-frequency ultrasonic conditions, the ultrasonic dispersion after the second ultrasonic treatment is subjected to a third ultrasonic treatment. Further, the ultrasonic frequency is 130kHz~200kHz. Further, the ultrasonic time is 40min~60min.

[0048] It is understandable that ultrasonic solvation of graphene oxide has the following advantages: 1. Improve the "incomplete cleaning" of inorganic impurities: Achieve penetration of strongly polar aprotic solvents into graphene oxide hard aggregates in stages. Specifically, mid-frequency ultrasound expands the penetration channels of strongly polar aprotic solvents; low-frequency ultrasound powerfully desorbs internal impurities; and high-frequency ultrasound removes trace residues. 2. Balancing “exfoliation and structural protection”: Mid-frequency lays the foundation for dispersion, low-frequency achieves efficient exfoliation, and high-frequency optimizes dispersion and layer structure stability, avoiding sheet breakage caused by low-frequency ultrasound alone, which makes it easy for impurities to be encapsulated in graphene oxide; or insufficient exfoliation caused by high-frequency ultrasound alone, which results in incomplete desorption of impurities. 3. Enhanced cleaning efficiency of highly polar aprotic solvents: The combination of medium-frequency, low-frequency, and high-frequency ultrasound is precisely matched with the dissolution and hydrogen bonding of highly polar aprotic solvents, maximizing the "dissolving impurities" and "aiding dispersion" functions of highly polar aprotic solvents and reducing the number of cleaning cycles.

[0049] It can also be understood that mid-frequency ultrasound at 60kHz~100kHz provides a gentle and balanced cavitation effect and mechanical shear force. This not only breaks up loose aggregates of GO in the strongly polar aprotic solvent, preventing the formation of hard aggregates, but also initially widens the interlayer spacing of GO, creating channels for the penetration of the strongly polar aprotic solvent. This allows the strongly polar aprotic solvent, as a polar organic solvent, to quickly dissolve soluble impurities adsorbed on the GO surface, such as residual hydrochloride and a small amount of unreacted sodium nitrate. This gentle and thorough process allows the strongly polar aprotic solvent to uniformly wash the GO surface, achieving surface pre-cleaning. In addition, mid-frequency ultrasound at 60kHz~100kHz can effectively promote the formation of hydrogen bonds between the strongly polar aprotic solvent and the hydroxyl and carboxyl groups on the GO surface, initially inhibiting the re-agglomeration of GO sheets. At the same time, it allows the strongly polar aprotic solvent to slowly penetrate into the gaps between GO layers, laying the groundwork for subsequent deep desorption of impurities. During this stage, there is no violent impact, and the GO sheet structure remains intact, avoiding premature damage to the GO sheets that would cause impurities to be trapped at the fracture edges, affecting subsequent cleaning. Low-frequency ultrasound (20kHz~40kHz) has a strong cavitation effect. The shock wave and high-speed microjets can directly destroy the hydrogen bonds and van der Waals forces between GO layers, achieving multilayer to few-layer / single-layer exfoliation. At the same time, it powerfully disperses incompletely dispersed hard agglomerates in the strongly polar aprotic solvent, such as GO agglomerates encapsulating impurities. In addition, the strong shock wave of the 20kHz~40kHz low-frequency ultrasound creates an "instantaneous negative-positive pressure alternation" inside the GO agglomerates, forcing the strongly polar aprotic solvent to quickly penetrate to the agglomerate core, dissolving the insoluble impurities encapsulated inside, such as unreacted graphite particles and residual potassium permanganate decomposition products, achieving deep impurity desorption. It can also reduce the interfacial tension between GO layers, making it difficult for the exfoliated GO layers to recombine. Meanwhile, the strongly polar aprotic solvent adsorbs on the GO surface, preventing impurities from being re-adsorbed, thus improving cleaning durability. High-frequency ultrasound (130kHz–200kHz) provides weak cavitation and gentle, uniform mechanical shearing force, emphasizing fine dispersion. This disperses soft aggregates remaining after low-frequency ultrasound and modifies the edges of GO sheets without damaging the already exfoliated GO sheet structure. Furthermore, the 130kHz–200kHz high-frequency ultrasound drives the highly polar aprotic solvent to undergo high-frequency micro-motion, washing away trace impurities remaining on the edges and surface of GO sheets, such as small molecules adsorbed on oxygen-containing functional groups, achieving precise removal of residual impurities. The hydrogen bonds between the highly polar aprotic solvent and GO are more stable under high-frequency ultrasound, further improving the dispersion uniformity of GO in the solvent and preventing localized impurity enrichment due to uneven dispersion after cleaning. This stage generates almost no new defects, and the highly polar aprotic solvent protects the oxygen-containing functional groups on the GO surface, preserving active sites for subsequent functionalization modifications, such as polymer composites.

[0050] In one embodiment, the pretreated graphene oxide is reduced under stirring conditions. Further, the stirring speed is 700 r / min to 900 r / min. Further, the reduction operation of the pretreated graphene oxide includes some or all of the following steps: S510. The pretreated graphene oxide is subjected to pH adjustment treatment with ammonia water to make the pH of the pretreated graphene oxide 8~9.

[0051] S520. The pretreated graphene oxide is subjected to oxime reduction treatment using hydroxylamine hydrochloride. Further, the mass ratio of graphene oxide to hydroxylamine hydrochloride is 3:(5~10).

[0052] S530. The pretreated graphene oxide is reduced using hydrazine hydrate. Further, the ratio of the mass of graphene oxide to the volume of hydrazine hydrate is (5~8) g / (2~5) mL.

[0053] Furthermore, after the hydrazine hydrate was completely added, the pretreated graphene oxide was further heated and stirred. Further, the temperature was raised to 85℃~95℃. Further, the stirring time was 3.5h~4.5h.

[0054] It is understandable that mixing graphene oxide with hydroxylamine hydrochloride reduces the carbonyl group of graphene oxide, decreases the dielectric constant and polarity of graphene oxide, thereby further improving the oleophilicity of graphene oxide, and lengthening the molecular chain of the modified groups in graphene oxide and enhancing its flexibility and shielding properties. Furthermore, the combination with hydrazine hydrate further reduces the oxygen-containing groups such as hydroxyl, carboxyl, and epoxy groups in graphene oxide.

[0055] In one embodiment, after the reduction operation of the pretreated graphene oxide, the graphene preparation method further includes the following step: mixing the pretreated graphene oxide with protonated polyaniline. Further, the mixing of the pretreated graphene oxide with protonated polyaniline is performed at a stirring speed of 700 r / min to 900 r / min. Further, the mixing of the pretreated graphene oxide with protonated polyaniline is specifically performed as follows: dissolving protonated polyaniline in water to prepare a protonated polyaniline solution, and then adding the pretreated graphene oxide dropwise to the protonated polyaniline solution while stirring. Further, the concentration of protonated polyaniline in the protonated polyaniline solution is 0.5 mg / mL to 2 mg / mL. Further, the pretreated graphene oxide is added dropwise to the protonated polyaniline solution while stirring, with a dropping rate of 0.15 g / s to 0.25 g / s. Further, pretreated graphene oxide was added dropwise to the protonated polyaniline solution and stirred. The addition rate was 0.2 g / s. Further, the ratio of graphene oxide to protonated polyaniline in the protonated polyaniline solution was (1.5~3):1. Further, the ratio of graphene oxide to protonated polyaniline in the protonated polyaniline solution was 2:1.

[0056] In one embodiment, pretreated graphene oxide is added dropwise to a protonated polyaniline solution. After the pretreated graphene oxide has been completely added, it is subjected to ultrasonic composite treatment, followed by washing and filtration. Further, the ultrasonic frequency is 50Hz~70Hz. Further, the ultrasonic frequency is 60Hz. Further, the ultrasonic time is 2h~3h. Further, a strongly polar aprotic solvent is used for washing. Further, the washing is performed 1~2 times. This application also provides graphene prepared by the graphene preparation method of any of the above embodiments. Further, in this embodiment, the method for preparing graphene includes the following steps: obtaining graphite; acid-treating the graphite to disperse it in concentrated sulfuric acid to obtain a graphite dispersion; oxidizing the graphite to react the graphite dispersion with potassium permanganate and hydrogen peroxide in sequence, and obtaining graphene oxide after filtration; solvating the graphene oxide by adding it to a strongly polar aprotic solvent for purification and modification to obtain pretreated graphene oxide; and reducing the pretreated graphene oxide.

[0057] This application also provides a graphene slurry, comprising a dispersant, a solvent, and graphene from any of the above embodiments. Further, the graphene slurry comprises the following components in parts by weight: 5%–10% dispersant; 80%–90% solvent; and 5%–10% graphene.

[0058] In one embodiment, the dispersant is at least one of ethyl cellulose, hydroxypropyl cellulose, and fatty alcohol polyoxyethylene ether.

[0059] In one embodiment, the solvent is at least one selected from terpineol, dibutyl phthalate, butyl carbitol acetate, and N,N'-dimethylformamide. Further, butyl carbitol acetate is also known as diethylene glycol butyl ether acetate.

[0060] It is understood that by limiting the types of dispersants and solvents, and dispersing the graphene prepared by the graphene preparation method of any of the above embodiments to obtain graphene slurry, the dispersion stability and dispersion uniformity of graphene are well achieved.

[0061] Compared with the prior art, the present invention has at least the following advantages: The graphene preparation method of the present invention involves acid treatment of graphite followed by oxidation treatment, resulting in graphene oxide with a large interlayer spacing. Further, the graphene oxide is solvated to achieve purification, impurity removal, interlayer intercalation, and interface modification. This method effectively ensures that the graphene oxide maintains good dispersion stability even at high reduction levels, while also guaranteeing the high conductivity of the obtained graphene.

[0062] The embodiments of this application will be described in detail below with reference to examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of this application. For experimental methods in the following embodiments where specific conditions are not specified, please refer to the guidelines given in this application, or follow experimental manuals or conventional conditions in the art, or follow the conditions recommended by the manufacturer, or refer to experimental methods known in the art.

[0063] In the specific embodiments described below, the measurement parameters involving raw material components may have slight deviations within the weighing accuracy range unless otherwise specified. Temperature and time parameters are subject to acceptable deviations due to instrument testing accuracy or operational precision.

[0064] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0065] Example 1 Expanded graphite was ground and passed through a 200-mesh sieve. 15 kg of concentrated sulfuric acid was added to 1 kg of expanded graphite, the reaction temperature was 90 °C, and the reaction was carried out for 4.5 h. After cooling to room temperature, a graphite dispersion was obtained. Under the condition of stirring speed of 300 r / min and temperature controlled at 0℃, 2.5 kg of potassium permanganate was slowly added to the graphite dispersion for 2 h, and the addition rate of potassium permanganate was 0.1 g / min; then, the temperature was raised to 30℃ and stirred for 2 h; then, 45 kg of deionized water was added to the graphite dispersion and the temperature was raised to 95℃ and stirred for 4 h. Under the condition of stirring speed of 300 r / min, the graphite dispersion after mixing with potassium permanganate was added dropwise to 0.5% hydrogen peroxide, the volume ratio of hydrogen peroxide to graphite dispersion was 10:1, and the stirring time was 4 h; then, the graphite dispersion after mixing with hydrogen peroxide was washed and filtered with deionized water, and the washing and filtration were performed 3 times to obtain graphene oxide. At an ultrasonic frequency of 60 kHz, 1 kg of graphene oxide was added to 120 kg of a strongly polar aprotic solvent for ultrasonic treatment for 35 min. Then, the ultrasonic frequency was adjusted to 20 kHz for further ultrasonic treatment for 25 min. Finally, the ultrasonic frequency was adjusted to 130 kHz for further ultrasonic treatment for 40 min to obtain pretreated graphene oxide. Under a stirring speed of 700 r / min, ammonia was added to the pretreated graphene oxide until the pH reached 8. Then, hydroxylamine hydrochloride was added, with a mass ratio of graphene oxide to hydroxylamine hydrochloride of 3:5. Next, hydrazine hydrate was added, with a mass ratio of graphene oxide to hydrazine hydrate of 5 g / 2 mL. After the hydrazine hydrate was completely added, the temperature was raised to 85 °C, and stirring was continued for 4.5 h. The mixture was then washed and filtered once using a strongly polar aprotic solvent.

[0066] Example 2 Expanded graphite was ground and passed through a 200-mesh sieve. Add 15 kg of concentrated sulfuric acid to 1 kg of expanded graphite, react at 90 °C for 4.5 h, and then cool to room temperature to obtain a graphite dispersion. Under the condition of stirring speed of 300 r / min and temperature controlled at 0℃, 2.5 kg of potassium permanganate was slowly added to the graphite dispersion for 2 h, and the addition rate of potassium permanganate was 0.1 g / min; then, the temperature was raised to 30℃ and stirred for 2 h; then, 45 kg of deionized water was added to the graphite dispersion and the temperature was raised to 95℃ and stirred for 4 h. Under the condition of stirring speed of 300 r / min, the graphite dispersion after mixing with potassium permanganate was added dropwise to 0.5% hydrogen peroxide, the volume ratio of hydrogen peroxide to graphite dispersion was 10:1, and the stirring time was 4 h; then, the graphite dispersion after mixing with hydrogen peroxide was washed and filtered with deionized water, and the washing and filtration were performed 3 times to obtain graphene oxide. Graphene oxide was added to a strongly polar aprotic solvent at an ultrasonic frequency of 80 kHz for 40 min. Then, the ultrasonic frequency was adjusted to 30 kHz for further ultrasonic treatment for 30 min. Finally, the ultrasonic frequency was adjusted to 170 kHz for further ultrasonic treatment for 50 min to obtain pretreated graphene oxide. Under a stirring speed of 700 r / min, ammonia was added to the pretreated graphene oxide until the pH reached 8. Then, hydroxylamine hydrochloride was added, with a mass ratio of graphene oxide to hydroxylamine hydrochloride of 3:5. Next, hydrazine hydrate was added, with a mass ratio of graphene oxide to hydrazine hydrate of 5 g / 2 mL. After the hydrazine hydrate was completely added, the temperature was raised to 85 °C, and stirring was continued for 4.5 h. The mixture was then washed and filtered once using a strongly polar aprotic solvent.

[0067] Example 3 Expanded graphite was ground and passed through a 200-mesh sieve. Add 15 kg of concentrated sulfuric acid to 1 kg of expanded graphite, react at 90 °C for 4.5 h, and then cool to room temperature to obtain a graphite dispersion. Under the condition of stirring speed of 300 r / min and temperature controlled at 0℃, 2.5 kg of potassium permanganate was slowly added to the graphite dispersion for 2 h, and the addition rate of potassium permanganate was 0.1 g / min; then, the temperature was raised to 30℃ and stirred for 2 h; then, 45 kg of deionized water was added to the graphite dispersion and the temperature was raised to 95℃ and stirred for 4 h. Under the condition of stirring speed of 300 r / min, the graphite dispersion after mixing with potassium permanganate was added dropwise to 0.5% hydrogen peroxide, the volume ratio of hydrogen peroxide to graphite dispersion was 10:1, and the stirring time was 4 h; then, the graphite dispersion after mixing with hydrogen peroxide was washed and filtered with deionized water, and the washing and filtration were performed 3 times to obtain graphene oxide. Graphene oxide was added to a strongly polar aprotic solvent at an ultrasonic frequency of 100 kHz for 45 min. Then, the ultrasonic frequency was adjusted to 40 kHz for further ultrasonic treatment for 35 min. Finally, the ultrasonic frequency was adjusted to 200 kHz for further ultrasonic treatment for 60 min to obtain pretreated graphene oxide. Under a stirring speed of 700 r / min, ammonia was added to the pretreated graphene oxide until the pH reached 8. Then, hydroxylamine hydrochloride was added, with a mass ratio of graphene oxide to hydroxylamine hydrochloride of 3:5. Next, hydrazine hydrate was added, with a mass ratio of graphene oxide to hydrazine hydrate of 5 g / 2 mL. After the hydrazine hydrate was completely added, the temperature was raised to 85 °C, and stirring was continued for 4.5 h. The mixture was then washed and filtered once using a strongly polar aprotic solvent.

[0068] Example 4 Expanded graphite was ground and passed through a 200-mesh sieve. Add 15 kg of concentrated sulfuric acid to 1 kg of expanded graphite, react at 90 °C for 4.5 h, and then cool to room temperature to obtain a graphite dispersion. Under the condition of stirring speed of 300 r / min and temperature controlled at 0℃, 2.5 kg of potassium permanganate was slowly added to the graphite dispersion for 2 h, and the addition rate of potassium permanganate was 0.1 g / min; then, the temperature was raised to 30℃ and stirred for 2 h; then, 45 kg of deionized water was added to the graphite dispersion and the temperature was raised to 95℃ and stirred for 4 h. Under the condition of stirring speed of 300 r / min, the graphite dispersion after mixing with potassium permanganate was added dropwise to 0.5% hydrogen peroxide, the volume ratio of hydrogen peroxide to graphite dispersion was 10:1, and the stirring time was 4 h; then, the graphite dispersion after mixing with hydrogen peroxide was washed and filtered with deionized water, and the washing and filtration were performed 3 times to obtain graphene oxide. Graphene oxide was added to a strongly polar aprotic solvent at an ultrasonic frequency of 80 kHz for 40 min. Then, the ultrasonic frequency was adjusted to 30 kHz for further ultrasonic treatment for 30 min. Finally, the ultrasonic frequency was adjusted to 170 kHz for further ultrasonic treatment for 50 min to obtain pretreated graphene oxide. Under a stirring speed of 900 r / min, ammonia was added to the pretreated graphene oxide until the pH reached 9. Then, hydroxylamine hydrochloride was added, with a mass ratio of graphene oxide to hydroxylamine hydrochloride of 3:10. Next, hydrazine hydrate was added, with a mass ratio of graphene oxide to hydrazine hydrate of 8 g / 5 mL. After the hydrazine hydrate was completely added, the temperature was raised to 95 °C, and stirring was continued for 3.5 h. The mixture was then washed and filtered twice using a strongly polar aprotic solvent.

[0069] Example 5 Expanded graphite was ground and passed through a 200-mesh sieve. Add 25 kg of concentrated sulfuric acid to 1 kg of expanded graphite, react at 90 °C for 3.5 h, and then cool to room temperature to obtain a graphite dispersion. Under the condition of stirring speed of 300 r / min and temperature controlled at 5℃, 3.0 g of potassium permanganate was slowly added to the graphite dispersion for 4 h, and the addition rate of potassium permanganate was 0.1 g / min. Then, the temperature was raised to 38℃ and the stirring time was 1 h. Then, 55 kg of deionized water was added to the graphite dispersion and the temperature was raised to 102℃ and the stirring time was 2 h. Under the condition of stirring speed of 300 r / min, the graphite dispersion after mixing with potassium permanganate was added dropwise to 27.5% hydrogen peroxide, the volume ratio of hydrogen peroxide to graphite dispersion was 10:1, and the stirring time was 2 h; then, the graphite dispersion after mixing with hydrogen peroxide was washed and filtered with deionized water, and the washing and filtration were performed 5 times to obtain graphene oxide. Graphene oxide was added to a strongly polar aprotic solvent at an ultrasonic frequency of 80 kHz for 40 min. Then, the ultrasonic frequency was adjusted to 30 kHz for further ultrasonic treatment for 30 min. Finally, the ultrasonic frequency was adjusted to 170 kHz for further ultrasonic treatment for 50 min to obtain pretreated graphene oxide. Under a stirring speed of 900 r / min, ammonia was added to the pretreated graphene oxide until the pH reached 9. Then, hydroxylamine hydrochloride was added, with a mass ratio of graphene oxide to hydroxylamine hydrochloride of 3:10. Next, hydrazine hydrate was added, with a mass ratio of graphene oxide to hydrazine hydrate of 8 g / 5 mL. After the hydrazine hydrate was completely added, the temperature was raised to 95 °C, and stirring was continued for 3.5 h. The mixture was then washed and filtered twice using a strongly polar aprotic solvent.

[0070] Example 6 Expanded graphite was ground and passed through a 200-mesh sieve. Add 25 kg of concentrated sulfuric acid to 1 kg of expanded graphite, react at 90 °C for 3.5 h, and then cool to room temperature to obtain a graphite dispersion. Under the condition of stirring speed of 300 r / min and temperature controlled at 5℃, 3.0 g of potassium permanganate was slowly added to the graphite dispersion for 4 h, and the addition rate of potassium permanganate was 0.1 g / min. Then, the temperature was raised to 38℃ and the stirring time was 1 h. Then, 55 kg of deionized water was added to the graphite dispersion and the temperature was raised to 102℃ and the stirring time was 2 h. Under the condition of stirring speed of 300 r / min, the graphite dispersion after mixing with potassium permanganate was added dropwise to 27.5% hydrogen peroxide, the volume ratio of hydrogen peroxide to graphite dispersion was 10:1, and the stirring time was 2 h; then, the graphite dispersion after mixing with hydrogen peroxide was washed and filtered with deionized water, and the washing and filtration were performed 5 times to obtain graphene oxide. Graphene oxide was added to a strongly polar aprotic solvent at an ultrasonic frequency of 80 kHz for 40 min. Then, the ultrasonic frequency was adjusted to 30 kHz for further ultrasonic treatment for 30 min. Finally, the ultrasonic frequency was adjusted to 170 kHz for further ultrasonic treatment for 50 min to obtain pretreated graphene oxide. Under a stirring speed of 900 r / min, ammonia was added to the pretreated graphene oxide until the pH reached 9; then, hydroxylamine hydrochloride was added, with a mass ratio of graphene oxide to hydroxylamine hydrochloride of 3:10; then, hydrazine hydrate was added, with a mass ratio of graphene oxide to hydrazine hydrate of 8 g / 5 mL. After the hydrazine hydrate was completely added, the temperature was raised to 95 °C, and stirring was continued for 3.5 h. The reduced graphene oxide was added dropwise to protonated polyaniline at a concentration of 0.5 mg / mL at a dropwise rate of 0.15 g / s. The mass ratio of protonated polyaniline to graphene oxide was 1.5:1. After the graphene oxide was completely added, the mixture was sonicated at a frequency of 50 Hz for 2 hours. Then, it was washed and filtered once using a strongly polar aprotic solvent.

[0071] Example 7 Expanded graphite was ground and passed through a 200-mesh sieve. Add 25 kg of concentrated sulfuric acid to 1 kg of expanded graphite, react at 90 °C for 3.5 h, and then cool to room temperature to obtain a graphite dispersion. Under the condition of stirring speed of 300 r / min and temperature controlled at 5℃, 3.0 g of potassium permanganate was slowly added to the graphite dispersion for 4 h, and the addition rate of potassium permanganate was 0.1 g / min. Then, the temperature was raised to 38℃ and the stirring time was 1 h. Then, 55 kg of deionized water was added to the graphite dispersion and the temperature was raised to 102℃ and the stirring time was 2 h. Under the condition of stirring speed of 300 r / min, the graphite dispersion after mixing with potassium permanganate was added dropwise to 27.5% hydrogen peroxide, the volume ratio of hydrogen peroxide to graphite dispersion was 10:1, and the stirring time was 2 h; then, the graphite dispersion after mixing with hydrogen peroxide was washed and filtered with deionized water, and the washing and filtration were performed 5 times to obtain graphene oxide. Graphene oxide was added to a strongly polar aprotic solvent at an ultrasonic frequency of 80 kHz for 40 min. Then, the ultrasonic frequency was adjusted to 30 kHz for further ultrasonic treatment for 30 min. Finally, the ultrasonic frequency was adjusted to 170 kHz for further ultrasonic treatment for 50 min to obtain pretreated graphene oxide. Under a stirring speed of 900 r / min, ammonia was added to the pretreated graphene oxide until the pH reached 9; then, hydroxylamine hydrochloride was added, with a mass ratio of graphene oxide to hydroxylamine hydrochloride of 3:10; then, hydrazine hydrate was added, with a mass ratio of graphene oxide to hydrazine hydrate of 8 g / 5 mL. After the hydrazine hydrate was completely added, the temperature was raised to 95 °C, and stirring was continued for 3.5 h. The reduced graphene oxide was added dropwise to protonated polyaniline at a concentration of 2 mg / mL at a dropping rate of 0.25 g / s. The mass ratio of protonated polyaniline to graphene oxide was 3:1. After the graphene oxide was completely added, the mixture was sonicated at a frequency of 70 Hz for 3 hours. Then, it was washed and filtered twice using a strongly polar aprotic solvent.

[0072] Example 8 Preparation of graphene slurry: Take 5g of graphene from Examples 1-7 above, 7g of ethyl cellulose and 88g of terpineol, mix and stir to disperse evenly to obtain graphene slurry.

[0073] Example 9 Preparation of graphene slurry: Take 8g of graphene from Examples 1-7 above, 10g of hydroxypropyl cellulose and 82g of dibutyl phthalate, mix and stir to disperse evenly to obtain graphene slurry.

[0074] Example 10 Preparation of graphene slurry: Take 10g of graphene from Examples 1-7 above, 5g of fatty alcohol polyoxyethylene ether and 85g of butyl carbitol acetate, mix and stir to disperse evenly to obtain graphene slurry.

[0075] Comparative Example 1 Expanded graphite was ground and passed through a 200-mesh sieve. Add 15 kg of concentrated sulfuric acid to 1 kg of expanded graphite, react at 90 °C for 4.5 h, and then cool to room temperature to obtain a graphite dispersion. Under the condition of stirring speed of 300 r / min, the temperature was raised to 38℃, the graphite dispersion was added to 3 kg of potassium permanganate, followed by 45 kg of deionized water, and stirred for 8 h; 27.5% hydrogen peroxide was added dropwise, the volume ratio of hydrogen peroxide to graphite dispersion was 10:1, the stirring time was 2 h, the sample was washed 5 times with deionized water, and the graphene oxide was obtained by vacuum filtration. Under a stirring speed of 900 r / min, ammonia was added to graphene oxide to adjust the pH to 10, 1 L of hydrazine hydrate was added, the temperature was raised to 100℃, and the mixture was stirred for 6 h. Graphene was obtained by washing with deionized water and then filtering.

[0076] Preparation of graphene slurry: Take 5g of the above graphene, 7g of ethyl cellulose and 88g of terpineol, mix and stir to disperse evenly to obtain graphene slurry.

[0077] Comparative Example 2 Expanded graphite was ground and passed through a 200-mesh sieve. Add 15 kg of concentrated sulfuric acid to 1 kg of expanded graphite, react at 90 °C for 4.5 h, and then cool to room temperature to obtain a graphite dispersion. Under the condition of stirring speed of 300 r / min, the temperature was raised to 38℃, the graphite dispersion was added to 3 kg of potassium permanganate, followed by 45 kg of deionized water, and stirred for 8 h; 27.5% hydrogen peroxide was added dropwise, the volume ratio of hydrogen peroxide to graphite dispersion was 10:1, the stirring time was 2 h, the sample was washed 5 times with deionized water, and the graphene oxide was obtained by vacuum filtration. Under the condition of stirring speed of 900 r / min, ammonia water was added to graphene oxide to adjust the pH to 7, 1 L of hydrazine hydrate was added, the temperature was raised to 70℃, stirred for 2 h, and graphene was obtained by washing with deionized water and filtration. Preparation of graphene slurry: Take 5g of the above graphene, 7g of ethyl cellulose and 88g of terpineol, mix and stir to disperse evenly to obtain graphene slurry.

[0078] Please refer to the following: Figure 1 The image shown is a scanning electron microscope (SEM) image of the graphene obtained in Example 5. It reveals that the graphene exfoliation effect is relatively good. The graphene obtained in Examples 1-5 has a volume resistivity of no more than 1.2 × 10⁻⁶. -3 The conductivity is good, and the graphene slurry prepared by further examples 8-10 has a supernatant ratio of no more than 7% after standing for 30 days. The absolute value of the ZeTa potential is >30mV, indicating good dispersion stability.

[0079] The graphene obtained in Examples 6-7 has a volume resistivity of no more than 1.0 × 10⁻⁶. -3 The graphene slurry exhibits good conductivity (Ω·cm), and after standing for 30 days, the supernatant content does not exceed 6%, the absolute value of the ZeTa potential is >32mV, and the dispersion stability is good.

[0080] Please refer to the following: Figure 2 The image shown is a scanning electron microscope (SEM) image of the graphene obtained in Comparative Example 1. The graphene in Comparative Example 1 exhibits relatively poor exfoliation performance, while the graphene obtained in Comparative Example 1 has a volume resistivity of 8.5 × 10⁻⁻⁻⁻⁶. 4The graphene slurry exhibits good conductivity (Ω·cm), but after standing for 30 days, the supernatant accounts for 45% of the total volume, and the absolute value of the zeta potential is only 18.2mV, indicating poor dispersion stability.

[0081] The graphene slurry obtained in Comparative Example 2 has a volume resistivity as high as 5.2 × 10⁻⁻⁻⁶. 2 The graphene slurry, with a high Ω·cm conductivity, exhibited poor conductivity. After standing for 30 days, the supernatant accounted for only 6% of the total supernatant, while the absolute value of the zeta potential reached 35.7mV, indicating good dispersion stability.

[0082] The above embodiments merely illustrate several implementation methods of this application to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Furthermore, it should be understood that after reading the above teachings of this application, those skilled in the art can make various alterations or modifications to this application, and the equivalent forms obtained also fall within the scope of protection of this application. It should also be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A method for preparing graphene, characterized in that, Includes the following steps: Obtain graphite; The graphite is subjected to acid treatment to disperse it in concentrated sulfuric acid, thereby obtaining a graphite dispersion. The graphite is subjected to oxidation treatment so that the graphite dispersion is mixed and reacted sequentially with potassium permanganate and hydrogen peroxide, and then filtered to obtain graphene oxide. The graphene oxide is subjected to solvation treatment, in which the graphene oxide is added to a strongly polar aprotic solvent for purification and modification to obtain pretreated graphene oxide. The pretreated graphene oxide is then reduced.

2. The method for preparing graphene according to claim 1, characterized in that, The strongly polar aprotic solvent is at least one selected from N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolinone, and sulfolane; and / or, The mass ratio of the graphene oxide to the strongly polar aprotic solvent is 1:(120~200).

3. The method for preparing graphene according to claim 1, characterized in that, The graphene oxide is subjected to ultrasonic solvation treatment, in which the graphene oxide is added to the strongly polar aprotic solvent for purification and modification under ultrasonic conditions.

4. The method for preparing graphene according to claim 3, characterized in that, The graphene oxide is subjected to ultrasonic solvation treatment at an ultrasonic frequency of 20 kHz to 200 kHz; and / or, The graphene oxide was subjected to ultrasonic solvation treatment for 1.5 h to 2.5 h.

5. The method for preparing graphene according to claim 1, characterized in that, The reduction operation of the pretreated graphene oxide includes the following steps: The pretreated graphene oxide was subjected to pH adjustment treatment with ammonia water to make the pH of the pretreated graphene oxide 8-9. The pretreated graphene oxide was subjected to oxime reduction treatment using hydroxylamine hydrochloride; The pretreated graphene oxide was reduced using hydrazine hydrate.

6. The method for preparing graphene according to claim 1, characterized in that, Following the step of reducing the pretreated graphene oxide, the method for preparing graphene further includes the following steps: The pretreated graphene oxide was mixed with protonated polyaniline.

7. The method for preparing graphene according to claim 6, characterized in that, The pretreated graphene oxide was mixed with protonated polyaniline, and the specific operation was as follows: Protonated polyaniline was dissolved in water to prepare a protonated polyaniline solution, and the pretreated graphene oxide was added dropwise to the protonated polyaniline solution and stirred to mix.

8. A graphene, characterized in that, The graphene was prepared by any one of the preparation methods of claims 1 to 7.

9. A graphene slurry, characterized in that, Includes dispersants, solvents, and the graphene as described in claim 9.

10. The graphene slurry according to claim 9, characterized in that, The dispersant is at least one selected from ethyl cellulose, hydroxypropyl cellulose, and fatty alcohol polyoxyethylene ether; and / or, The solvent is at least one selected from terpineol, dibutyl phthalate, butyl carbitol acetate, and N,N'-dimethylformamide; and / or The graphene slurry comprises the following components in parts by weight: 5%~10% dispersant; 80%~90% solvent; and 5%~10% graphene.

Images