Graphite nanosheet-pitch-based carbon fiber modified carbon paper with high electric conductivity and high thermal conductivity and preparation method of graphite nanosheet-pitch-based carbon fiber modified carbon paper

Abstract

The invention discloses graphite nanosheet-pitch-based carbon fiber modified carbon paper with high electric conductivity and high thermal conductivity and a preparation method thereof. By introducing the graphite nanosheets and the pitch-based carbon fibers, horizontal and longitudinal electric conduction and heat conduction channels are formed, and the electric conductivity and the heat conductivity of the carbon paper are effectively improved. The method mainly comprises the following steps: 1) preparing a pitch-based carbon fiber and chopped wet polyacrylonitrile-based carbon fiber composite felt; 2) preparing a graphite nanosheet dispersion liquid; 3) introducing the graphite nanosheets into the carbon fiber composite felt; 4) introducing phenolic resin, drying and curing; and 5) carrying out carbonization and graphitization treatment to obtain the graphite nanosheet-pitch-based carbon fiber modified carbon paper. The method provided by the invention can be used for preparing the high-conductivity and high-heat-conductivity modified carbon paper, has the characteristics of high process operability, high yield, small resistance, small thermal resistance and high reliability, can effectively improve the energy conversion efficiency of the fuel cell, and is suitable for large-scale batch industrial production.

Description

Technical Field

[0001] The invention belongs to the field of carbon paper, and specifically relates to a high-conductivity and high-thermal-conductivity graphite nanosheet-asphalt-based carbon fiber modified carbon paper and a preparation method thereof. Background Art

[0002] Due to factors such as global warming and the continuous consumption of non-renewable fossil energy, environmental pollution and energy crisis are becoming increasingly prominent, and the global energy consumption structure is accelerating its transformation to low-carbon. In this energy revolution, hydrogen energy is regarded as a disruptive technology direction for the future energy revolution because of its advantages such as clean and pollution-free, high energy density per unit mass, storability, renewability, and wide sources, and has received new attention at the basic research and industrial application levels. Among them, as the main downstream application of hydrogen energy, hydrogen fuel cell vehicles are in the development stage. In hydrogen fuel cells, the gas diffusion layer (GDL) is a key component. It is not only responsible for the uniform distribution of gas, but also for the conduction of current and heat management. Traditional gas diffusion layer materials, such as carbon paper, have certain electrical conductivity and air permeability, but there is still room for improvement in electrical conductivity and thermal conductivity. Especially in high power density and fast response hydrogen fuel cell applications, due to the internal temperature changes and the heat generated by chemical reactions, the gas diffusion layer needs to have good thermal conductivity to ensure the effective transmission and distribution of heat, prevent local overheating, and ensure the stable operation of the fuel cell. At the same time, high conductivity is crucial to reducing the internal resistance of the fuel cell and improving the energy conversion efficiency.

[0003] Traditional carbon paper uses polyacrylonitrile-based carbon fibers as raw materials. Due to the limitations of the raw materials themselves, it is difficult to improve their electrical and thermal conductivity. However, emerging materials such as graphite nanosheets and asphalt-based carbon fibers have excellent electrical and thermal conductivity and can be used to modify traditional carbon paper.

[0004] For example, graphite nanosheets, as a two-dimensional material, have excellent electrical and thermal conductivity. Evenly dispersing graphite nanosheets in carbon fiber paper can form a conductive and thermal conductive network, significantly improving the overall electrical and thermal conductivity of the material.

[0005] For another example, asphalt-based carbon fiber has excellent properties such as high modulus, high thermal conductivity, good heat resistance and creep resistance. Compared with polyacrylonitrile-based carbon fiber, asphalt-based carbon fiber has a higher degree of graphitization and lower resistivity, which is beneficial to improving the electrical conductivity and thermal conductivity of carbon fiber paper.

[0006] The present invention introduces asphalt-based carbon fibers into carbon paper by mixing asphalt-based carbon fibers and short-cut wet-process polyacrylonitrile-based carbon fibers into felt, and then uses a pre-impregnated graphite nanosheet dispersion to uniformly attach graphite nanosheets to the carbon fibers to prepare graphite nanosheet-asphalt-based carbon fiber modified carbon paper with high electrical conductivity and high thermal conductivity. The preparation method provided by the present invention has the characteristics of strong process operability, high yield rate, low electrical resistance, low thermal resistance, and high reliability, and is suitable for large-scale batch industrial production. Summary of the invention

[0007] The purpose of the present invention is to provide a highly conductive and thermally conductive graphite nanosheet-asphalt-based carbon fiber modified carbon paper and a preparation method thereof, so as to solve the problems of poor electrical and thermal conductivity of carbon paper in the prior art, large internal resistance of the battery and large thermal resistance, and effectively improve the energy conversion efficiency of the fuel cell.

[0008] 1. A high-conductivity and high-thermal-conductivity graphite nanosheet-asphalt-based carbon fiber modified carbon paper and its preparation method. It is characterized in that the main components include: asphalt-based carbon fiber, short-cut wet-process polyacrylonitrile-based carbon fiber, graphite nanosheet and carbon formed by high-temperature carbonization of phenolic resin; its production steps include:

[0009] S01, preparing a composite carbon fiber dispersion: mixing asphalt-based carbon fibers of a certain length, short-cut wet-process polyacrylonitrile-based carbon fibers, deionized water and a modifier in a certain order and a certain proportion to obtain a composite carbon fiber dispersion;

[0010] S02, preparing a composite carbon fiber felt: using a composite carbon fiber dispersion as a raw material, preparing a composite carbon fiber felt through a wet felting and drying process;

[0011] S03, preparing a graphite nanosheet dispersion: mixing graphite nanosheets, a dispersant and deionized water in a certain proportion, and dispersing them at a certain speed for a certain time through a dispersing device to obtain a graphite nanosheet dispersion;

[0012] S04, introducing graphite nanosheets: introducing a graphite nanosheet dispersion into the composite carbon fiber felt by an impregnation or lamination process under the action of traction, and then drying at a certain temperature to obtain a graphite nanosheet-composite carbon fiber felt;

[0013] S05, introducing phenolic resin: introducing a certain concentration of high carbonization rate phenolic resin solution into the graphite nanosheet-composite carbon fiber felt by a dipping or laminating process, and then drying at a certain temperature to obtain a dipping graphite nanosheet-composite carbon fiber felt;

[0014] S06, hot pressing and curing: hot pressing and curing the impregnated graphite nanosheet composite carbon fiber felt obtained in step S05 at a certain temperature and a certain pressure, and controlling the thickness to obtain a cured graphite nanosheet composite carbon fiber felt;

[0015] S07, high temperature carbonization and graphitization: the solidified graphite nanosheet composite carbon fiber felt obtained in S06 is carbonized and graphitized in sequence to obtain a highly conductive and thermally conductive graphite nanosheet-asphalt-based carbon fiber modified carbon paper.

[0016] 2. Further, it is characterized in that the pitch-based carbon fiber of step S01 has a length of 100-600 μm and a thermal conductivity greater than 100 W / (m·K); the short-cut wet-process polyacrylonitrile-based carbon fiber of step S01 has a length of 3-5 mm and is prepared by a wet process, and grooves can be observed on the surface; the mixing order of step S01 is to first add the modifier to deionized water, and then add the asphalt-based carbon fiber and the polyacrylonitrile-based carbon fiber in sequence; the modifier of step S01 is one or more of polyethylene oxide (PEO), polyacrylamide (PAM), and sodium dodecylbenzene sulfonate (SDBS), with a mass concentration of 1 to 3‰, the mass concentration of asphalt-based carbon fiber is 0.1 to 3‰, and the mass concentration of polyacrylonitrile-based carbon fiber is 0.3 to 5‰;

[0017] 3. Further, it is characterized in that the graphite nanosheets in step S03 have a sheet diameter of 2-10 μm and a thickness of 5-50 nm; the dispersant in step S03 is one or more of sodium carboxymethyl cellulose (CMC), hydroxypropyl methyl cellulose (HPMC), and hydroxyethyl cellulose (HEC), the mass concentration of the graphite nanosheets is 1-5%, and the mass concentration of the dispersant is 1-5‰; the dispersion speed in step S03 is 300-3000 r / min, and the time is 1-24h;

[0018] 4. Further, it is characterized in that the impregnation process of step S04 refers to immersing the composite carbon fiber felt in the graphite nanosheet dispersion; the coating process of step S04 refers to spraying the graphite nanosheet dispersion onto the composite carbon fiber felt; the drying temperature of step S04 is 105-150°C;

[0019] 5. Further, it is characterized in that the dipping process in step S05 refers to immersing the graphite nanosheet-composite carbon fiber felt into a certain concentration of high carbonization rate phenolic resin solution; the coating process in step S05 refers to spraying a certain concentration of high carbonization rate phenolic resin solution onto the graphite nanosheet-composite carbon fiber felt; the phenolic resin in step S05 has a residual carbon rate greater than 60%, and its solvent is anhydrous ethanol or deionized water, with a mass concentration of 10-50%; the drying temperature in step S05 is 70-165°C;

[0020] 6. Further, it is characterized in that the temperature of hot pressing curing in step S06 is 180-210°C, the pressure is 0.1-5MPa, and the thickness is 50-500μm;

[0021] 7. Further, it is characterized in that the carbonization temperature of step S07 is 1100-1500°C, and the graphitization temperature is 2300-2800°C;

[0022] 8. A high electrical conductivity and high thermal conductivity graphite nanosheet-asphalt-based carbon fiber modified carbon paper, characterized in that the carbon paper is prepared by the method of any one of claims 1 to 7, has the characteristics of high electrical conductivity and high thermal conductivity, and its horizontal thermal conductivity is greater than 15W / (m·K), the longitudinal thermal conductivity is greater than 1W / (m·K), and the resistivity is less than 6mΩ·cm.

[0023] Compared with the prior art, the present invention has the following advantages.

[0024] (1) The present invention provides a method for preparing highly conductive and highly thermally conductive graphite nanosheet-asphalt-based carbon fiber modified carbon paper, thereby obtaining modified carbon paper with excellent electrical conductivity and thermal conductivity, greatly reducing the internal resistance and thermal resistance of the battery, and effectively improving the energy conversion efficiency of the fuel cell;

[0025] (2) The present invention adopts a method of mixing and dispersing asphalt-based carbon fibers and short-cut wet-process polyacrylonitrile-based carbon fibers into a felt, so that part of the asphalt-based carbon fibers can be vertically inserted between the layers of carbon paper, which significantly enhances the longitudinal heat conduction capacity of the carbon paper, effectively reduces the longitudinal thermal resistance of the battery, and improves the heat dissipation efficiency of the battery;

[0026] (3) The present invention uses an impregnation or coating process to introduce graphite nanosheets, which effectively solves the problem of difficult dispersion of nanomaterials such as graphite nanosheets, increases the introduction content of graphite nanosheets, and thus improves the electrical and thermal conductivity of carbon paper;

[0027] (4) The entire preparation process has few steps and is relatively simple to operate, making it suitable for industrial mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the process flow of the present invention;

[0029] Figure 2 (a) is a plane scanning electron microscope image of asphalt-based carbon fiber-polyacrylonitrile-based carbon fiber composite carbon fiber felt;

[0030] Figure 2 (b) is a vertical scanning electron microscope image of a pitch-based carbon fiber-polyacrylonitrile-based carbon fiber composite carbon fiber felt;

[0031] Figure 3 (a) is a high-magnification scanning electron microscope image of traditional polyacrylonitrile-based carbon fiber paper;

[0032] Figure 3(b) is a high-magnification scanning electron microscope image of graphite nanosheet-pitch-based carbon fiber modified carbon paper;

[0033] Figure 3 (c) is a high-magnification scanning electron microscope image of the vertical surface of traditional polyacrylonitrile-based carbon fiber paper;

[0034] Figure 3 (d) is a high-magnification scanning electron microscope image of the vertical surface of the graphene nanosheet-pitch-based carbon fiber modified carbon paper;

[0035] Figure 4 (a) is a planar scanning electron microscope image of traditional polyacrylonitrile-based carbon fiber paper;

[0036] Figure 4 (b) is a planar scanning electron micrograph of graphite nanosheet-pitch-based carbon fiber modified carbon paper; Specific implementation methods

[0038] The highly conductive and thermally conductive graphite nanosheet-asphalt-based carbon fiber modified carbon paper and the preparation method thereof of the present invention are further described in conjunction with the accompanying drawings. The present invention is further described in detail below in conjunction with implementation cases.

[0039] Example 1

[0040] A method for preparing high-conductive and high-thermal-conductive graphite nanosheet-asphalt-based carbon fiber modified carbon paper, such as Figure 1 As shown, the following steps are included:

[0041] S01, preparing a composite carbon fiber dispersion: adding a pitch-based carbon fiber with a length of 200 μm and a thermal conductivity of 1000 W / (m·K) and a short-cut polyacrylonitrile-based carbon fiber with a length of 3 mm and a groove structure on the surface prepared by a wet process to a mixed polyethylene oxide (PEO) aqueous solution, wherein the mass concentration of polyethylene oxide (PEO) is 2‰, the mass concentration of the pitch-based carbon fiber is 0.3‰, and the mass concentration of the polyacrylonitrile-based carbon fiber is 0.5‰, to obtain a composite carbon fiber dispersion;

[0042] S02, preparing a composite carbon fiber felt: using a composite carbon fiber dispersion as a raw material, preparing a composite carbon fiber felt through a wet felting and drying process;

[0043] S03, preparing a graphite nanosheet dispersion: mixing graphite nanosheets, hydroxyethyl cellulose (HEC) and deionized water, wherein the graphite nanosheets have a sheet diameter of 2-10 μm, a thickness of 5-50 nm, a mass concentration of 2%, and a mass concentration of hydroxyethyl cellulose (HEC) of 2‰, and dispersing at 800 r / min for 2 h through a dispersing device to obtain a graphite nanosheet dispersion;

[0044] S04, introducing graphite nanosheets: introducing a graphite nanosheet dispersion into the composite carbon fiber felt through an impregnation process under the action of traction, and then drying at 105° C. to obtain a graphite nanosheet-composite carbon fiber felt;

[0045] S05, introducing phenolic resin: introducing 10wt.% of high carbonization rate phenolic resin solution into the graphite nanosheet-composite carbon fiber felt through a dipping process, wherein the residual carbon rate of the phenolic resin is 68%, and the solvent is anhydrous ethanol; and then drying at 75°C to obtain a dipping graphite nanosheet-composite carbon fiber felt;

[0046] S06, hot pressing and curing: hot pressing and curing the impregnated graphite nanosheet composite carbon fiber felt obtained in step S05 at a temperature of 180° C. and a pressure of 0.2 MPa, and controlling the thickness to be 180 μm, to obtain a cured graphite nanosheet composite carbon fiber felt;

[0047] S07, high temperature carbonization and graphitization: the solidified graphite nanosheet composite carbon fiber felt obtained in S06 is carbonized at 1300°C and graphitized at 2300°C in sequence to obtain a highly conductive and thermally conductive graphite nanosheet-asphalt-based carbon fiber modified carbon paper.

[0048] Mixing pitch-based carbon fiber and short-cut wet-process polyacrylonitrile-based carbon fiber into felt can make the pitch-based carbon fiber distributed in the carbon felt in an orderly manner. The length of the pitch-based carbon fiber is 200μm, and the length of the short-cut polyacrylonitrile-based carbon fiber is 3mm, so Figure 2 In the figure, the short fibers marked with red dotted circles are pitch-based carbon fibers. Figure 2 As shown, a portion of the asphalt-based carbon fibers are horizontally overlapped between the carbon fibers, which strengthens the horizontal connection between the carbon fibers and enriches the thermal and electrical conductive pathways of the carbon paper in the horizontal direction; another portion of the asphalt-based carbon fibers are vertically inserted between the layers of the carbon felt to form a three-dimensional interlocking structure, which forms an additional thermal conductive pathway in the vertical direction and enhances the thermal conduction efficiency of the modified carbon paper in the vertical direction.

[0049] After the introduction of graphite nanosheets, the conventional polyacrylonitrile-based carbon fiber carbon paper and the prepared graphite nanosheet-pitch-based carbon fiber modified carbon paper were characterized by scanning electron microscopy. Figure 3 As shown. Graphite nanosheets are attached to the carbon fibers and wrap the entire carbon fibers. The graphite nanosheets are in contact with each other, adding more fine branch structures to the skeleton formed by the interlaced arrangement of carbon fibers. These fine branch structures bring complexity to the thermal and electrical conductive network, making the entire network more developed, thereby improving the thermal and electrical conductivity of the modified carbon paper.

[0050] Figure 4This is a plane scan of traditional polyacrylonitrile-based carbon fiber carbon paper and graphite nanosheet-pitch-based carbon fiber modified carbon paper. Compared with traditional polyacrylonitrile-based carbon fiber carbon paper, the pores on the surface of the modified carbon paper are reduced, but the stacking structure of the carbon paper can still be observed.

[0051] Example 2

[0052] The preparation process is basically the same as that in Example 1, except that the mass concentration of the asphalt-based carbon fiber is 0.15‰, and other process and material parameters are the same.

[0053] Example 3

[0054] The preparation process is basically the same as that in Example 1, except that the asphalt-based carbon fiber used in the preparation process has a length of 500 μm and a thermal conductivity of 600 W / (m·K), and other process and material parameters are the same.

[0055] Example 4

[0056] The preparation process is basically the same as that in Example 1, except that the asphalt-based carbon fiber is not introduced, and other process and material parameters are the same.

[0057] Comparative Example

[0058] The preparation process is basically the same as that in Example 1, except that pitch-based carbon fibers and graphite nanosheets are not introduced, and other process and material parameters are the same.

[0059] The above examples 1-3 and the comparative example were tested, and the specific results are as follows:

[0060]

[0061]

[0062] Comparing Example 4 and the comparative example, when preparing the carbon paper of Example 4, a graphite nanosheet dispersion with a content of 2wt.% was introduced, and the planar thermal conductivity of the carbon paper increased from 10.89W / (m·K) to 23.90W / (m·K), the longitudinal thermal conductivity increased from 0.09W / (m·K) to 1.34W / (m·K), and the planar resistivity decreased from 10.2mΩ·cm to 5.61mΩ·cm. The introduction of graphite nanosheets provides more fine branches for the conductive and thermal conductive network of the carbon paper, which greatly improves the conductive and thermal conductive properties of the carbon paper.

[0063] Comparing Example 2 and Example 4, when preparing the carbon paper of Example 2, a graphite nanosheet dispersion with a content of 2wt.% was introduced, and a pitch-based carbon fiber with a content of 0.15wt.‰ was also introduced into the mixed carbon fiber dispersion; when preparing the carbon paper of Example 4, only a graphite nanosheet dispersion with a content of 2wt.% was introduced. The planar thermal conductivity of the carbon paper increased from 23.90W / (m·K) to 28.67W / (m·K), the longitudinal thermal conductivity increased from 1.34W / (m·K) to 2.61W / (m·K), and the planar resistivity decreased from 5.61mΩ·cm to 5.27mΩ·cm. The addition of pitch-based carbon fibers forms additional thermal and electrical conductive pathways in the carbon paper, further increasing the thermal conductivity of the carbon paper and reducing the resistivity of the carbon paper.

[0064] Comparing Example 1 and Example 2, when preparing the carbon paper of Example 1, a graphite nanosheet dispersion with a content of 2wt.% was introduced, and a pitch-based carbon fiber with a content of 0.3wt.‰ was introduced into the mixed carbon fiber dispersion; when preparing the carbon paper of Example 2, a graphite nanosheet dispersion with a content of 2wt.% was introduced, and a pitch-based carbon fiber with a content of 0.15wt.‰ was introduced into the mixed carbon fiber dispersion. The planar thermal conductivity of the carbon paper increased from 28.67W / (m·K) to 32.37W / (m·K), the longitudinal thermal conductivity increased from 2.61W / (m·K) to 4.05W / (m·K), and the planar resistivity decreased from 5.27mΩ·cm to 4.77mΩ·cm. The electrical and thermal conductivity of the carbon paper increased with the increase of the content of the pitch-based carbon fiber in the carbon paper.

[0065] Comparing Example 3 with Example 1, the length of the asphalt-based carbon fiber of the carbon paper in Example 3 is 500 μm, and the thermal conductivity is 600 W / (m·K); the length of the asphalt-based carbon fiber of the carbon paper in Example 1 is 200 μm, and the thermal conductivity is 1000 W / (m·K). The planar thermal conductivity of the carbon paper is reduced from 32.37 W / (m·K) to 31.62 W / (m·K), the longitudinal thermal conductivity is reduced from 4.05 W / (m·K) to 1.82 W / (m·K), and the planar resistivity is increased from 4.77 mΩ·cm to 5.14 mΩ·cm. It can be seen from the data that the length and thermal conductivity of the asphalt-based carbon fiber have an impact on the electrical and thermal conductivity of the carbon paper finally prepared.

[0066] In summary, the present invention introduces asphalt-based carbon fibers and graphite nanosheets into carbon paper. The thermal conductivity of asphalt-based carbon fibers is better than that of traditional polyacrylonitrile-based carbon fibers, providing an additional conductive and thermal conductive pathway for carbon paper. At the same time, the addition of graphite nanosheet fillers further improves the conductive and thermal conductive network of carbon paper, making the graphite nanosheet-asphalt-based carbon fiber modified carbon paper have superior conductive and thermal conductive capabilities.

[0067] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A high-conductivity and high-thermal-conductivity graphite nanosheet-pitch-based carbon fiber modified carbon paper and a preparation method thereof. Characterized in that: The main components include: asphalt-based carbon fiber, short-cut wet-process polyacrylonitrile-based carbon fiber, graphite nanosheets and carbon formed by high-temperature carbonization of phenolic resin; its production steps include: S01, preparing a composite carbon fiber dispersion: mixing asphalt-based carbon fibers of a certain length, short-cut wet-process polyacrylonitrile-based carbon fibers, deionized water and a modifier in a certain order and a certain proportion to obtain a composite carbon fiber dispersion; S02, preparing a composite carbon fiber felt: using a composite carbon fiber dispersion as a raw material, preparing a composite carbon fiber felt through a wet felting and drying process; S03, preparing a graphite nanosheet dispersion: mixing graphite nanosheets, a dispersant and deionized water in a certain proportion, and dispersing them at a certain speed for a certain time through a dispersing device to obtain a graphite nanosheet dispersion; S04, introducing graphite nanosheets: introducing a graphite nanosheet dispersion into the composite carbon fiber felt by an impregnation or lamination process under the action of traction, and then drying at a certain temperature to obtain a graphite nanosheet-composite carbon fiber felt; S05, introducing phenolic resin: introducing a certain concentration of high carbonization rate phenolic resin solution into the graphite nanosheet-composite carbon fiber felt by a dipping or laminating process, and then drying at a certain temperature to obtain a dipping graphite nanosheet-composite carbon fiber felt; S06, hot pressing and curing: hot pressing and curing the impregnated graphite nanosheet composite carbon fiber felt obtained in step S05 at a certain temperature and a certain pressure, and controlling the thickness to obtain a cured graphite nanosheet composite carbon fiber felt; S07, high temperature carbonization and graphitization: the solidified graphite nanosheet composite carbon fiber felt obtained in S06 is carbonized and graphitized in sequence to obtain a highly conductive and thermally conductive graphite nanosheet-asphalt-based carbon fiber modified carbon paper.

2. The preparation method according to claim 1, characterized in that: The asphalt-based carbon fiber of step S01 has a length of 100-600 μm and a thermal conductivity greater than 100 W / (m·K); the short-cut wet-process polyacrylonitrile-based carbon fiber of step S01 has a length of 3-5 mm and is prepared by a wet process, and grooves can be observed on the surface; the mixing order of step S01 is to first add the modifier to deionized water, and then add the asphalt-based carbon fiber and the polyacrylonitrile-based carbon fiber in sequence; the modifier of step S01 is one or more of polyethylene oxide (PEO), polyacrylamide (PAM), and sodium dodecylbenzene sulfonate (SDBS), with a mass concentration of 1 to 3‰, the mass concentration of the asphalt-based carbon fiber is 0.1 to 3‰, and the mass concentration of the polyacrylonitrile-based carbon fiber is 0.3 to 5‰.

3. The preparation method according to claim 1, characterized in that: The graphite nanosheets in step S03 have a sheet diameter of 2-10 μm and a thickness of 5-50 nm; the dispersant in step S03 is one or more of sodium carboxymethyl cellulose (CMC), hydroxypropyl methyl cellulose (HPMC), and hydroxyethyl cellulose (HEC), the mass concentration of the graphite nanosheets is 1-5%, and the mass concentration of the dispersant is 1-5‰; the dispersion speed in step S03 is 300-3000 r / min, and the time is 1-24h.

4. The preparation method according to claim 1, characterized in that: The impregnation process of step S04 refers to immersing the composite carbon fiber felt in the graphite nanosheet dispersion; the coating process of step S04 refers to spraying the graphite nanosheet dispersion onto the composite carbon fiber felt; the drying temperature of step S04 is 105-150°C.

5. The preparation method according to claim 1, characterized in that: The dipping process in step S05 refers to immersing the graphite nanosheet-composite carbon fiber felt into a high carbonization rate phenolic resin solution of a certain concentration; the coating process in step S05 refers to spraying a high carbonization rate phenolic resin solution of a certain concentration onto the graphite nanosheet-composite carbon fiber felt; the phenolic resin in step S05 has a residual carbon rate greater than 60%, and its solvent is anhydrous ethanol or deionized water, with a mass concentration of 10-50%; the drying temperature in step S05 is 70-165°C.

6. The preparation method according to claim 1, characterized in that: The temperature of the hot pressing curing in step S06 is 180-210° C., the pressure is 0.1-5 MPa, and the thickness is 50-500 μm.

7. The preparation method according to claim 1, characterized in that The carbonization temperature of step S07 is 1100-1500°C, and the graphitization temperature is 2300-2800°C.

8. A high electrical and thermal conductivity graphite nanosheet-pitch-based carbon fiber modified carbon paper, characterized in that: The carbon paper is prepared by the method of any one of claims 1 to 7, and has the characteristics of high electrical conductivity and high thermal conductivity, with a horizontal thermal conductivity greater than 15 W / (m·K), a longitudinal thermal conductivity greater than 1 W / (m·K), and a resistivity less than 6 mΩ·cm.

Images