Graphene conductive material and preparation method thereof

Abstract

The invention discloses a graphene conductive material and a preparation method thereof, and relates to the technical field of preparation of graphene conductive materials.The graphene conductive material is prepared from 100 parts of graphene, 10-30 parts of conductive polymer, 0.5-2 parts of gold nanoparticles, 1-5 parts of graphene quantum dots and 1-5 parts of nanometer titania particulates. The efficient stripping of the graphene is realized by combining the colloid chemical volume repulsive interaction; according to the method, a complex chemical oxidation reduction process is not needed, high-temperature and strong acid treatment is avoided, and energy consumption and process complexity are remarkably reduced; meanwhile, by controlling generation of bubbles and liquid phase shearing force, uniform stripping of graphene is realized, and the problems of low stripping efficiency and high energy consumption in the prior art are solved.

Description

Technical Field

[0001] The invention relates to the technical field of graphene conductive material preparation, in particular to a graphene conductive material and a preparation method thereof. Background Art

[0002] Graphene, a carbon material with a unique two-dimensional structure, is widely used in conductive materials, composite materials, electronic devices and other fields due to its excellent mechanical, electrical, thermal and optical properties.

[0003] After searching, the Chinese patent announcement number CN107603218A discloses a graphene conductive material. This technology significantly improves the dispersibility and conductivity of graphene by compounding graphene oxide with a variety of conductive substances (such as polyaniline, acetylene carbon black, etc.) and using a specific conductive dispersion and cyanamide graphene alcohol solution for surface modification. The conductivity of the graphene conductive material prepared can reach 17.6~20.1 S / cm, which is significantly improved compared to traditional graphene oxide (0.01~0.03 S / cm); However, the prior art still has some limitations in the preparation process. For example, the preparation of its conductive dispersion requires complex esterification reaction and high temperature treatment, which increases the complexity and energy consumption of the process. In addition, although the cyanamide graphene alcohol solution used in this technology improves the surface reactivity of graphene, it is still difficult to achieve uniform dispersion of graphene in the polymer matrix in practical applications; in addition, the doping and composite process of graphene in the prior art is relatively cumbersome, and has a certain damage to the crystal structure of graphene, which may lead to a decrease in the mechanical properties of the material.

[0004] To this end, the present invention provides a high-efficiency, low-energy-consumption and environmentally friendly graphene conductive material and a preparation method thereof. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a graphene conductive material and a preparation method thereof, which solves the problems of the prior art mentioned in the background art, such as complex process, high energy consumption, difficulty in uniform dispersion and possible destruction of the graphene crystal structure during the preparation process.

[0006] To achieve the above objectives, the present invention is implemented through the following technical scheme: a graphene conductive material and a preparation method thereof, wherein the ingredients include: 100 parts of graphene, 10 to 30 parts of conductive polymer, 0.5 to 2 parts of nano-gold particles, 1 to 5 parts of graphene quantum dots, and 1 to 5 parts of nano-titanium dioxide particles.

[0007] Preferably, the steps are as follows: S01. Preparation of graphene precursor: natural graphite powder is dispersed in deionized water, an appropriate amount of surfactant is added, tiny bubbles are introduced by ultrasonic treatment, and then exfoliation is performed under mechanical stirring to obtain a graphene precursor; bubbles are generated in situ between graphite layers to expand the distance between graphite layers, and the volume exclusion effect of colloidal chemistry is combined to promote efficient exfoliation of graphite under liquid phase mechanical shear force; S02. Graphene stripping: The graphene precursor obtained in S01 is placed in a liquid membrane electrolysis device, the electrolyte concentration and voltage are adjusted, the diffusion rate of water is controlled, and electrochemical stripping is performed to obtain high-quality single-layer graphene; by controlling the diffusion rate of water in the electrolyte, the oxidation process is made more uniform, and the electrolyte is layered using a special liquid membrane structure to effectively control the diffusion of water, thereby achieving uniform synthesis of graphene oxide; S03. Graphene surface functionalization: The exfoliated graphene obtained in S02 is dispersed in an ionic liquid, stirred at room temperature for 12 hours, and then washed with ethanol to obtain functionalized graphene; the graphene surface is modified by using an ionic liquid to enhance its dispersibility and conductivity, and the ionic liquid can form a stable interface layer with the graphene surface, thereby improving its compatibility with the electrolyte; S04. Doping modification of graphene: placing the functionalized graphene obtained in S03 in a plasma reactor, using nitrogen or borane gas as a doping source, and treating for 15 minutes to obtain doped graphene; by treating the graphene with low-temperature plasma to introduce doping elements, the high-energy particles in the plasma can accurately introduce the doping elements into the graphene lattice while maintaining the crystal structure of the graphene; S05. Composite of graphene: dispersing the doped graphene obtained in S04 in a solution containing pyrrole monomer, adding an appropriate amount of oxidant, and performing in-situ polymerization at room temperature to obtain a graphene / polymer composite material; through the in-situ polymerization reaction, the conductive polymer is uniformly grown on the surface of the graphene to form a composite material, which significantly improves the conductivity and mechanical properties of the composite material; S06. Forming of graphene composite materials: The graphene composite materials obtained in S05 are prepared into a slurry suitable for 3D printing, and are printed layer by layer according to a preset model, followed by drying. The graphene composite materials are formed into a target shape by using 3D printing technology, and the distribution and structure of the materials are precisely controlled according to design requirements, so as to realize the preparation of conductive materials with complex shapes; S07. Post-processing of graphene materials: placing the 3D printed graphene material obtained in S06 in a supercritical carbon dioxide drying device, controlling the temperature at 35°C and the pressure at 10MPa for 2 hours to obtain a dried graphene conductive material; the low surface tension and high diffusivity of supercritical carbon dioxide are used to dry the formed graphene material, thereby avoiding material shrinkage and structural damage caused by solvent volatilization in the traditional drying process; S08. Performance enhancement of graphene materials: The dried graphene material obtained in S07 is used as an electrode, placed in an electrolyte, and subjected to cyclic voltammetry or constant potential polarization treatment to optimize its electrochemical properties, thereby ultimately obtaining a high-performance graphene conductive material; the graphene conductive material is activated by electrochemical methods to further enhance its electrochemical properties, thereby introducing more active sites on the material surface and optimizing its conductivity and electrochemical stability.

[0008] Preferably, in step S01, the surfactant is selected from one or more of polyvinyl alcohol, polyethylene glycol, sodium lignin sulfonate, polyvinyl pyrrolidone (PVP) or sodium dodecylbenzene sulfonate, and the added amount of the surfactant is 0.5% to 5% of the mass of the graphite powder; the frequency of the ultrasonic treatment is 20kHz to 40kHz, and the treatment time is 10 minutes to 30 minutes, so as to enhance the uniform distribution of bubbles between graphite layers and the stripping efficiency.

[0009] Preferably, in the S02 step, the concentration of the electrolyte is 0.1 mol / L~1 mol / L, the voltage is controlled at 1V~5V, and the diffusion rate of water in the electrolyte is controlled by adjusting the thickness of the liquid film and the flow rate of the electrolyte; a multi-layer liquid film structure is adopted in the liquid membrane electrolysis device, and the thickness of each layer of the liquid film is 100μm~500μm, so as to further improve the diffusion uniformity of water in the electrolyte.

[0010] Preferably, in the step S03, the ionic liquid is one of 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate or 1-hexyl-3-methylimidazolium chloride, the treatment temperature of the ionic liquid is 20°C to 30°C, and the treatment time is 10 hours to 14 hours; and 0.1% to 1% by mass of nano-titanium dioxide particles are added to the ionic liquid to enhance the chemical modification effect of the graphene surface.

[0011] Preferably, in the step S04, the working pressure of the plasma reactor is 0.1Pa~1Pa, the plasma processing power is 30W~70W, and the doping gas flow rate is 10sccm~50sccm; a magnetic field auxiliary device is provided in the plasma reactor, and the magnetic field strength is 0.1T~0.5T to improve the uniform distribution of the doping elements in the graphene lattice.

[0012] Preferably, in the step S05, the concentration of the pyrrole monomer is 0.01 mol / L~0.1 mol / L, the oxidant is one of ammonium persulfate, potassium persulfate or sodium persulfate, and the added amount of the oxidant is 1%~10% of the mass of the pyrrole monomer; and 0.5%~2% by mass of nano-gold particles are added to the in-situ polymerization reaction to improve the conductivity and stability of the composite material.

[0013] Preferably, in step S06, the solid content of the 3D printing slurry is 10% to 30%, the temperature of the printing nozzle is 40° C. to 60° C., and the printing speed is 10 mm / s to 30 mm / s; and 1% to 5% by mass of graphene quantum dots are added to the 3D printing slurry to enhance the material properties after printing.

[0014] Preferably, in the step S07, the processing time of the supercritical carbon dioxide drying device is 1 hour to 3 hours, and the porosity of the dried graphene conductive material is 5% to 20%; the drying device is provided with a microwave assisted heating device, and the microwave power is 100W to 500W to accelerate the drying process and further optimize the material structure.

[0015] Preferably, in the step S08, the scan rate of the cyclic voltammetry is 10mV / s~100mV / s, the potential of the constant potential polarization treatment is -1V~1V, and the treatment time is 0.5 hour~2 hours; and an ionic liquid additive with a mass percentage of 0.1%~0.5% is added during the electrochemical treatment to further improve the electrochemical properties of the material.

[0016] The present invention provides a graphene conductive material and a preparation method thereof, which has the following beneficial effects: (1) High-efficiency exfoliation and low-energy preparation: The present invention adopts bubble-assisted liquid-phase mechanical exfoliation technology, combined with colloidal chemical volume exclusion, to achieve high-efficiency exfoliation of graphene. This method does not require a complex chemical oxidation-reduction process, avoids high temperature and strong acid treatment, and significantly reduces energy consumption and process complexity. At the same time, by controlling the generation of bubbles and liquid-phase shear force, uniform exfoliation of graphene is achieved, solving the problems of low exfoliation efficiency and high energy consumption in the prior art. (2) Excellent dispersibility and conductivity: The present invention modifies the graphene surface by ionic liquid, thereby enhancing the compatibility and dispersibility between graphene and the polymer matrix; the ionic liquid can form a stable interface layer on the graphene surface, effectively preventing the agglomeration of graphene, thereby achieving uniform dispersion in the composite material; in addition, the low-temperature plasma doping technology further optimizes the electrical properties of graphene, significantly improving its conductivity, and solving the problems of insufficient graphene dispersibility and unstable conductivity in the prior art; (3) Precise structural control and high performance: The present invention uses in-situ polymerization and 3D printing technology to achieve precise molding and microstructure control of graphene composite materials. Through 3D printing technology, the distribution and shape of the material can be precisely controlled according to design requirements to prepare conductive materials with complex structures. At the same time, supercritical carbon dioxide drying and electrochemical activation treatment further optimize the pore structure and electrochemical properties of the material, significantly improve the mechanical properties and conductive stability of the material, and solve the problems of complex molding and insufficient performance of composite materials in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Embodiment 1: Raw material composition (parts by weight): natural graphite powder: 100 parts, deionized water: 1200 parts, surfactant (polyvinyl alcohol): 10 parts, ionic liquid (1-ethyl-3-methylimidazolium tetrafluoroborate): 250 parts, nitrogen (doping gas): as needed, pyrrole monomer: 20 parts, ammonium persulfate (oxidant): 5 parts, nano-gold particles: 1 part, graphene quantum dots: 3 parts; Preparation method: Step 1: Disperse natural graphite powder in deionized water, add polyvinyl alcohol, ultrasonically treat for 15 minutes, and mechanically stir and peel to obtain a graphene precursor; Step 2: placing the precursor in a liquid membrane electrolysis device, with an electrolyte concentration of 0.5 mol / L and a voltage of 3 V, and controlling the diffusion rate of water for electrochemical stripping; Step 3: dispersing the exfoliated graphene in an ionic liquid, stirring at room temperature for 12 hours, and washing with ethanol to obtain functionalized graphene; Step 4: placing the functionalized graphene in a plasma reactor with a nitrogen flow rate of 30 sccm for 15 minutes to obtain doped graphene; Step 5: dispersing the doped graphene in the pyrrole monomer solution, adding ammonium persulfate, and performing an in-situ polymerization reaction at room temperature; Step 6: Prepare the composite material into 3D printing slurry, and after printing, treat it in a supercritical carbon dioxide drying device for 2 hours; Step 7: Use the dried material as an electrode and perform cyclic voltammetry to optimize the electrochemical performance.

[0019] Embodiment 2: Raw material composition (parts by weight): natural graphite powder: 100 parts, deionized water: 1500 parts, surfactant (polyethylene glycol): 15 parts, ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate): 300 parts, borane (doping gas): as needed, pyrrole monomer: 25 parts, potassium persulfate (oxidant): 8 parts, nano-gold particles: 2 parts, graphene quantum dots: 5 parts; Preparation method: Step 1: Disperse natural graphite powder in deionized water, add polyethylene glycol, ultrasonically treat for 20 minutes, and mechanically stir and peel to obtain a graphene precursor; Step 2: placing the precursor in a liquid membrane electrolysis device, with an electrolyte concentration of 0.8 mol / L and a voltage of 4 V, and controlling the diffusion rate of water for electrochemical stripping; Step 3: dispersing the exfoliated graphene in an ionic liquid, stirring at room temperature for 14 hours, and washing with ethanol to obtain functionalized graphene; Step 4: placing the functionalized graphene in a plasma reactor with a borane flow rate of 40 sccm for 15 minutes to obtain doped graphene; Step 5: dispersing the doped graphene in the pyrrole monomer solution, adding potassium persulfate, and performing an in-situ polymerization reaction at room temperature; Step 6: Prepare the composite material into 3D printing slurry, and after printing, treat it in a supercritical carbon dioxide drying device for 2 hours; Step 7: Use the dried material as an electrode and perform constant potential polarization treatment to optimize the electrochemical performance.

[0020] Embodiment 3: Raw material composition (parts by weight): Natural graphite powder: 100 parts, deionized water: 1000 parts, surfactant (sodium dodecylbenzene sulfonate): 8 parts, ionic liquid (1-hexyl-3-methylimidazolium chloride): 200 parts, nitrogen (doping gas): as needed, pyrrole monomer: 15 parts, ammonium persulfate (oxidant): 3 parts, nanogold particles: 0.5 parts, graphene quantum dots: 2 parts; Preparation method: Step 1: Disperse natural graphite powder in deionized water, add sodium dodecylbenzene sulfonate, ultrasonicate for 10 minutes, and mechanically stir and peel to obtain a graphene precursor; Step 2: Place the precursor in a liquid membrane electrolysis device with an electrolyte concentration of 0.3 mol / L and a voltage of 2 V, and control the diffusion rate of water for electrochemical stripping; Step 3: dispersing the exfoliated graphene in an ionic liquid, stirring at room temperature for 10 hours, and washing with ethanol to obtain functionalized graphene; Step 4: placing the functionalized graphene in a plasma reactor with a nitrogen flow rate of 20 sccm for 15 minutes to obtain doped graphene; Step 5: dispersing the doped graphene in the pyrrole monomer solution, adding ammonium persulfate, and performing an in-situ polymerization reaction at room temperature; Step 6: Prepare the composite material into 3D printing slurry, and after printing, treat it in a supercritical carbon dioxide drying device for 2 hours; Step 7: Use the dried material as an electrode and perform cyclic voltammetry to optimize the electrochemical performance.

[0021] Comparative Example 1: Raw material composition (parts by weight): graphene oxide: 30 parts, conductive dispersion: 20 parts, aniline: 35 parts, ammonium persulfate: 1 part, melamine: 0.4 parts, tert-butyl para-diphenol: 0.1 parts, diphenylsilanediol: 4 parts, calcium propionate: 2 parts; Preparation method: The preparation method of the prior art (patent number CN107603218A) is adopted to carry out composite treatment through cyanamide graphene alcohol solution and conductive dispersion.

[0022] Comparative Example 2: Raw material composition (parts by weight): natural graphite powder: 100 parts, deionized water: 1200 parts, surfactant (polyvinyl alcohol): 10 parts, pyrrole monomer: 20 parts, ammonium persulfate (oxidant): 5 parts; Preparation method: The natural graphite powder was dispersed in deionized water, polyvinyl alcohol was added, ultrasonic treatment was performed for 15 minutes, and mechanical stirring and exfoliation were performed to obtain a graphene precursor; The precursor was directly mixed with pyrrole monomer and ammonium persulfate was added to carry out in-situ polymerization without ionic liquid modification and plasma doping treatment; The composite material was dried and then electrochemically treated.

[0023] The following are two tables showing the comparison of electrical and mechanical properties of three embodiments of the present invention and two comparative examples; Project / Indicator Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Conductivity (S / cm) 25.3 27.8 24.5 18.2 15.6 Resistivity (Ω·m) 0.039 0.036 0.041 0.055 0.064 Electrochemical stability (%) 95 96 94 88 85 Specific capacitance (F / g) 220 235 210 180 160 Cycle life (times) 5000 5200 4800 3500 3000 The three embodiments of the present invention are significantly better than the comparative examples in terms of electrical performance. The electrical conductivity is improved by 39%, 53% and 35% compared with the prior art (Comparative Example 1), and by 62%, 78% and 60% compared with the traditional method (Comparative Example 2). The lower resistivity indicates that the material has better electrical conductivity. The improvement in electrochemical stability, specific capacitance and cycle life further proves the advantages of the present invention in the field of high-performance conductive materials; Project / Indicator Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Tensile strength(MPa) 120 130 115 100 95 Elongation at break (%) 15 18 14 10 8 Elastic modulus(GPa) 1.2 1.3 1.1 0.9 0.8 Porosity(%) 10 8 12 15 18 Specific surface area (m² / g) 300 320 290 250 230 Surface roughness(nm) 5 4 6 8 10 The three embodiments of the present invention show significant advantages in mechanical properties and microstructure. The tensile strength, elongation at break and elastic modulus are all higher than those of the comparative example, indicating that the mechanical properties of the material are stronger. The optimization of porosity and specific surface area helps to improve the conductivity and electrochemical properties of the material. The lower surface roughness indicates that the surface of the material is more uniform, which helps to improve the interface compatibility of the composite material; By comparing the detailed data in the above two tables, it can be clearly seen that the comprehensive advantages of the present invention in terms of electrical properties, mechanical properties and microstructure regulation, reflecting the innovation and practicality of this solution.

[0024] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0025] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A graphene conductive material, characterized in that: The ingredients include: 100 parts of graphene, 10 to 30 parts of conductive polymer, 0.5 to 2 parts of nano gold particles, 1 to 5 parts of graphene quantum dots and 1 to 5 parts of nano titanium dioxide particles.

2. A method for preparing a graphene conductive material according to claim 1, characterized in that: The steps are as follows: S01. Preparation of graphene precursor: natural graphite powder is dispersed in deionized water, an appropriate amount of surfactant is added, tiny bubbles are introduced by ultrasonic treatment, and then peeled off under mechanical stirring to obtain a graphene precursor; bubbles are generated in situ between graphite layers to expand the distance between graphite layers, and the volume exclusion effect of colloidal chemistry is combined to promote efficient peeling of graphite under liquid phase mechanical shear force; S02. Graphene stripping: placing the graphene precursor obtained in S01 in a liquid membrane electrolysis device, adjusting the electrolyte concentration and voltage, controlling the diffusion rate of water, and performing electrochemical stripping to obtain high-quality single-layer graphene; by controlling the diffusion rate of water in the electrolyte, the oxidation process is made more uniform, and the electrolyte is layered using a special liquid membrane structure to effectively control the diffusion of water, thereby achieving uniform graphene oxide synthesis; S03. Graphene surface functionalization: The exfoliated graphene obtained in S02 is dispersed in an ionic liquid, stirred at room temperature for 12 hours, and then washed with ethanol to obtain functionalized graphene; the graphene surface is modified by using an ionic liquid to enhance its dispersibility and conductivity, and the ionic liquid can form a stable interface layer with the graphene surface to improve its compatibility with the electrolyte; S04. Doping modification of graphene: placing the functionalized graphene obtained in S03 in a plasma reactor, using nitrogen or borane gas as a doping source, and treating for 15 minutes to obtain doped graphene; by treating the graphene with low-temperature plasma to introduce doping elements, the high-energy particles in the plasma can accurately introduce the doping elements into the graphene lattice while maintaining the crystal structure of the graphene; S05. Composite of graphene: dispersing the doped graphene obtained in S04 in a solution containing a pyrrole monomer, adding an appropriate amount of an oxidant, and performing an in-situ polymerization reaction at room temperature to obtain a graphene / polymer composite material; Through in-situ polymerization, the conductive polymer is evenly grown on the graphene surface to form a composite material, which significantly improves the conductivity and mechanical properties of the composite material. S06. Forming of graphene composite materials: preparing the graphene composite materials obtained in S05 into a slurry suitable for 3D printing, printing and forming layer by layer according to a preset model, and then drying; forming the graphene composite materials into a target shape by using 3D printing technology, accurately controlling the distribution and structure of the materials according to design requirements, and realizing the preparation of conductive materials with complex shapes; S07. Post-processing of graphene materials: placing the 3D printed graphene material obtained in S06 in a supercritical carbon dioxide drying device, controlling the temperature at 35°C and the pressure at 10MPa for 2 hours to obtain a dried graphene conductive material; drying the formed graphene material by using the low surface tension and high diffusivity of supercritical carbon dioxide to avoid material shrinkage and structural damage caused by solvent volatilization in the traditional drying process; S08. Performance enhancement of graphene materials: The dried graphene material obtained in S07 is used as an electrode, placed in an electrolyte, and subjected to cyclic voltammetry or constant potential polarization treatment to optimize its electrochemical properties, thereby ultimately obtaining a high-performance graphene conductive material; the graphene conductive material is activated by electrochemical methods to further enhance its electrochemical properties, thereby introducing more active sites on the material surface and optimizing its conductivity and electrochemical stability.

3. A method for preparing a graphene conductive material according to claim 1, characterized in that: In the step S01, the surfactant is selected from one or more of polyvinyl alcohol, polyethylene glycol, sodium lignin sulfonate, polyvinyl pyrrolidone (PVP) or sodium dodecylbenzene sulfonate, and the added amount of the surfactant is 0.5% to 5% of the mass of the graphite powder; the frequency of the ultrasonic treatment is 20kHz to 40kHz, and the treatment time is 10 minutes to 30 minutes, so as to enhance the uniform distribution of bubbles between graphite layers and the stripping efficiency.

4. A method for preparing a graphene conductive material according to claim 1, characterized in that: In the S02 step, the concentration of the electrolyte is 0.1mol / L~1mol / L, the voltage is controlled at 1V~5V, and the diffusion rate of water in the electrolyte is controlled by adjusting the thickness of the liquid film and the flow rate of the electrolyte; a multi-layer liquid film structure is adopted in the liquid membrane electrolysis device, and the thickness of each layer of the liquid film is 100μm~500μm, so as to further improve the diffusion uniformity of water in the electrolyte.

5. A method for preparing a graphene conductive material according to claim 1, characterized in that: In the step S03, the ionic liquid is one of 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate or 1-hexyl-3-methylimidazolium chloride, the treatment temperature of the ionic liquid is 20°C to 30°C, and the treatment time is 10 hours to 14 hours; and 0.1% to 1% by mass of nano-titanium dioxide particles are added to the ionic liquid to enhance the chemical modification effect of the graphene surface.

6. A method for preparing a graphene conductive material according to claim 1, characterized in that: In the step S04, the working pressure of the plasma reactor is 0.1Pa~1Pa, the plasma processing power is 30W~70W, and the doping gas flow rate is 10sccm~50sccm; a magnetic field auxiliary device is provided in the plasma reactor, and the magnetic field strength is 0.1T~0.5T to improve the uniform distribution of the doping elements in the graphene lattice.

7. A method for preparing a graphene conductive material according to claim 1, characterized in that: In the step S05, the concentration of the pyrrole monomer is 0.01 mol / L~0.1 mol / L, the oxidant is one of ammonium persulfate, potassium persulfate or sodium persulfate, and the added amount of the oxidant is 1%~10% of the mass of the pyrrole monomer; 0.5%~2% by mass of nano-gold particles are added to the in-situ polymerization reaction to improve the conductivity and stability of the composite material.

8. A method for preparing a graphene conductive material according to claim 1, characterized in that: In the step S06, the solid content of the 3D printing slurry is 10% to 30%, the temperature of the printing nozzle is 40° C. to 60° C., and the printing speed is 10 mm / s to 30 mm / s; and 1% to 5% by mass of graphene quantum dots are added to the 3D printing slurry to enhance the material performance after printing.

9. A method for preparing a graphene conductive material according to claim 1, characterized in that: In the step S07, the processing time of the supercritical carbon dioxide drying device is 1 hour to 3 hours, and the porosity of the dried graphene conductive material is 5% to 20%; the drying device is provided with a microwave assisted heating device, and the microwave power is 100W to 500W to accelerate the drying process and further optimize the material structure.

10. A method for preparing a graphene conductive material according to claim 1, characterized in that: In the step S08, the scan rate of the cyclic voltammetry is 10mV / s~100mV / s, the potential of the constant potential polarization treatment is -1V~1V, and the treatment time is 0.5 hours~2 hours; during the electrochemical treatment, an ionic liquid additive with a mass percentage of 0.1%~0.5% is added to further improve the electrochemical properties of the material.

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