Carbon paper for fuel cell gas diffusion layer and method for manufacturing the same

Abstract

The application discloses a kind of carbon paper for fuel cell gas diffusion layer and its preparation method, belong to fuel cell technical field.The method is: carbon nanotube is oxidized in strong acid, and carboxylated carbon nanotube is obtained;It is mixed with soluble iron salt solution, sodium hydroxide solution is added, and ferroferric oxide / carbon nanotube composite is prepared;It is mixed with binder, resin diluent, distilled water, and Pickring emulsion adhesive is obtained;Carbon fiber is dispersed in aqueous solution containing dispersant and surfactant, and carbon fiber pulp is prepared by beating, and carbon fiber raw paper is obtained by papermaking;Carbon fiber raw paper is soaked in Pickring emulsion adhesive, in-situ demulsification is carried out, and carbon fiber adhesive raw paper is obtained;Carbon fiber adhesive raw paper is sequentially subjected to water removal, magnetic field control magnetic conductive particle orientation, and hot-pressing forming three processes, and carbon paper is obtained.The application method is simple, and the amount is less, cost is saved, environment is protected, and the problem that carbon paper crack is caused by multiple impregnation of resin is avoided.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fuel cells, and particularly relates to a high-conductivity carbon paper for a fuel cell gas diffusion layer and a preparation method thereof. BACKGROUND

[0002] A fuel cell is an energy conversion device that directly converts the chemical energy of fuel and oxidants into electrical energy. It has the advantages of not being affected by the Carnot cycle, high conversion efficiency, high efficiency, cleanliness (the reaction product is only water), and low noise. Its components mainly include: bipolar plates, gas diffusion layers, catalyst layers, and proton exchange membranes. Among them, the gas diffusion layer (GDL) in the proton exchange membrane fuel cell provides a gas diffusion channel, supports the material, and improves the performance of the fuel cell.

[0003] The GDL is usually composed of a pore base layer (MPS) and a microporous layer (MPL). The MPS is generally carbon fiber paper, carbon fiber woven cloth, non-woven fabric, and carbon black paper, etc. Carbon fiber paper is widely used due to its corrosion resistance, high electrical conductivity, good air permeability, high strength, smooth surface, and other advantages.

[0004] The typical manufacturing process of carbon fiber paper includes three main steps: wet laying, carbonization, and graphitization. In the wet laying process, carbon fibers (usually polyacrylonitrile PAN-based carbon fibers) are impregnated with carbonizable resin, which serves as an adhesive for the fibers, and a paper machine is used to form a thin layer of impregnated carbon fibers. The material is then hot-pressed to fuse the carbon fibers and solidify the resin; subsequently, carbonization and graphitization are performed.

[0005] Invention patent CN117886298A makes PAN-based pre-oxidized yarn into non-woven fabric, impregnates phenolic resin and molds and cures, performs low-temperature carbonization for the first time, then impregnates phenolic resin and cures for the second time, performs high-temperature carbonization, and finally performs graphitization.

[0006] Invention patent CN117904900A loads a thermosetting resin on a deposited carbon paper obtained by gas phase deposition on a carbon paper precursor, and sequentially performs low-temperature pre-curing, hot pressing, and carbonization treatment to obtain a densified carbon paper; the densified carbon paper is impregnated in a thermosetting resin ethanol solution, and sequentially performs low-temperature pre-curing, hot pressing, and carbonization treatment; the impregnation treatment step is repeated more than once, and then graphitization is performed to obtain a carbon paper for fuel cells.

[0007] In view of the existing related technologies, there are problems such as cracks in the carbon paper due to multiple impregnations of resin, low electrical conductivity and mechanical properties of the carbon paper, and high energy consumption and high cost of the preparation method. SUMMARY

[0008] The present application aims at solving the problems in the background art, and provides a carbon paper for fuel cell gas diffusion layer and a preparation method thereof, which can improve the conductivity and mechanical properties of the carbon paper and save cost.

[0009] To achieve the above-mentioned object, the technical scheme adopted by the present application is as follows.

[0010] A preparation method of a carbon paper for fuel cell gas diffusion layer, the method comprises the following steps:

[0011] (1) oxidizing carbon nanotubes under the condition of strong acid and ultrasonic to introduce carboxyl groups on the surface of the carbon nanotubes to obtain carboxylated carbon nanotubes;

[0012] (2) mixing the carboxylated carbon nanotubes with a solution containing soluble salts of divalent iron and trivalent iron, adding a small amount of sodium hydroxide solution, and preparing a ferroferric oxide / carbon nanotube composite by using a coprecipitation method;

[0013] (3) mixing 5-20wt% of the ferroferric oxide / carbon nanotube composite, 5-10wt% of a binder, 0.5-2wt% of a resin diluent, and 70-85wt% of distilled water to prepare a Pickring emulsion binder;

[0014] (4) dispersing carbon fibers in an aqueous solution containing a dispersant and a surfactant, preparing a carbon fiber slurry by beating, and obtaining a carbon fiber raw paper by papermaking using a papermaking forming paper machine; wherein the dispersant is 0.10wt%-0.25wt%, the surfactant is 0.01-0.03wt%, the carbon fiber is 0.05-0.1wt%, and the distilled water is 99.62wt%-99.77wt%;

[0015] (5) soaking the carbon fiber raw paper in the Pickring emulsion binder, breaking the emulsion particles in situ by the action of an alternating magnetic field, causing the binder / ferroferric oxide / carbon nanotube composite particles to precipitate, and adsorbing the particles at the fiber lap joint points by capillary action to obtain a carbon fiber bonding raw paper;

[0016] (6) sequentially performing three processes of water removal of the carbon fiber bonding raw paper, magnetic field control of the orientation of the magnetic conductive particles, and hot pressing forming, to obtain a carbon paper for fuel cell gas diffusion layer, which has high bonding strength, excellent conductivity, and low cost.

[0017] Further, in step (1), the strong acid is one or more of concentrated sulfuric acid, concentrated hydrochloric acid, or concentrated nitric acid, the oxidation temperature is 50-100℃, and the time is 3-8h.

[0018] Further, in step (2), the divalent iron is ferrous sulfate or ferrous chloride, the trivalent iron is ferric nitrate or ferric chloride, the concentration ratio of the divalent iron to the trivalent iron is 1:1.75, and the dosage ratio is 1:1.

[0019] Further, in step (2), the heating temperature of the co-precipitation method is 30-80℃, and the time is 2-6h.

[0020] Further, in step (3), the adhesive is one or more of phenol formaldehyde resin, epoxy resin (TDE-85), and epoxy resin (E51); and the resin diluent is one of n-hexane, triethylene tetramine, or polyether amine.

[0021] Further, in step (4), the length of the carbon fiber is one or more of 1-9mm; and the mass fraction of the carbon fiber in the carbon fiber slurry is 0.01wt%-0.1wt%.

[0022] Further, in step (4), the carbon fiber is one or more of polyacrylonitrile (PAN) based carbon fiber or pitch-based carbon fiber; the surfactant is one of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, or Tween-80; and the dispersant is one or more of polyethylene oxide (PEO), polyacrylamide (PAM), hydroxymethyl cellulose (CMC), and sodium hexametaphosphate.

[0023] Further, in step (6), the hot-pressing treatment temperature is 80-180℃, the pressure is 2.5-10Mpa, and the time is 30-120min.

[0024] A carbon paper for a fuel cell gas diffusion layer prepared by the above preparation method.

[0025] The beneficial effects of the present application relative to the prior art are:

[0026] 1. The present application uses Pickring emulsion as an adhesive to bond the chopped carbon fibers in a dotted line contact form, which has less impact on the conductivity of the carbon fiber three-dimensional network than the traditional method of wrapping phenol formaldehyde resin outside the chopped carbon fibers, and the carbon paper also has high conductivity without carbonization.

[0027] 2. The present application directly soaks the carbon fiber raw paper in the Pickring emulsion and bonds the carbon fibers by breaking the emulsion through a magnetic field, which is simple, saves cost, protects the environment, and avoids the problem of cracks in the carbon paper caused by multiple resin impregnations.

[0028] 3. Since the carbon paper does not need to be carbonized and graphitized, it not only reduces energy consumption but also avoids the problem of reduced mechanical strength of the carbon paper at high temperatures and has high porosity. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a preparation flowchart of ferroferric oxide / carbon nanotube composite;

[0030] Figure 2 is a particle size distribution chart of Pickring nanoemulsion;

[0031] Figure 3 is a Pickring nanoemulsion demulsification flow chart;

[0032] Figure 4 is a SEM chart of self-made carbon paper;

[0033] Figure 5 is a SEM chart of Japan Toray carbon paper;

[0034] Figure 6 is a planar resistivity comparison chart of different carbon papers. DETAILED DESCRIPTION

[0035] The specific embodiments of the present application are described in detail below, but it should be understood that the scope of protection of the present application is not limited by the specific embodiments. Based on the examples in the present application, all other examples obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application. The experimental methods described in the embodiments of the present application are conventional methods unless otherwise specified.

[0036] Example 1

[0037] First, the carbon nanotubes were oxidized by ultrasonic treatment in a mixture of concentrated nitric acid and concentrated sulfuric acid at a mass ratio of 1:3 at 60°C for 6h to introduce carboxyl groups on the surface of the carbon nanotubes to obtain carboxylated carbon nanotubes;

[0038] Second, as shown in Figure 1 , the carbon nanotubes were ultrasonically dispersed in 50ml of 1mol / L FeSO4 solution and 50ml of 1.75mol / L FeCl3 solution and mixed, 1mol / L sodium hydroxide solution was added dropwise until Ph=12, the temperature was raised to 50°C, heated for 3h, then 0.25g of sodium dodecyl sulfate was added, mixed uniformly, cooled to room temperature, the black precipitate in the solution was collected by filtration, washed with deionized water until neutral, dried and ground to obtain a Fe3O4 / carbon nanotube composite;

[0039] Then, 5wt% of the Fe3O4 / carbon nanotube composite, 14.5wt% of the phenolic resin prepolymer, 0.5wt% of n-hexane and 80wt% of distilled water were stirred in a high-speed disperser at 3000rmp / min for 30min to prepare a Pickring emulsion adhesive, and the particle size distribution chart is shown in Figure 2 ;

[0040] Short-cut carbon fibers of 9mm, 6mm, 3mm were mixed with a small amount of PEM, PEO and distilled water respectively to prepare several 0.067wt% carbon fiber slurries; carbon fiber raw paper was obtained by using a paper forming and paper making device, the carbon fiber raw paper was put into Pickring nano emulsion, and the emulsion was demulsified by using an alternating magnetic field, resin nanoparticles and ferroferric oxide / carbon nanotube composite were precipitated and entered the fiber lap joint, as shown in Figure 3 ;

[0041] After the carbon paper raw paper was freeze-dried to remove water, it was hot-pressed under the conditions of a temperature of 170℃, a pressure of 5Mpa and a time of 60min, and the orientation structure of the magnetic conductive particles was controlled by a magnetic field; during solidification, on the one hand, the pressure caused the nano adhesive to break, the adhesive components to solidify and bond, and on the other hand, the conductive particles to conduct the bonded carbon fibers, realizing the bonding and conductive dual functions to obtain a high-conductivity fuel cell gas diffusion layer carbon paper, the SEM image of the self-made carbon paper is shown in Figure 4 .

[0042] The carbon paper prepared by this method has a simple preparation method, a small amount of resin, low cost, and good conductivity of 12.11mΩ·cm without carbonization and graphitization, the planar resistivity of different carbon papers is shown in Figure 6 , the mechanical strength is high, which is 10.87MPa, and the thickness uniformity is good.

[0043] Example 2

[0044] First, the carbon nanotubes were oxidized by ultrasonic treatment in a mixture of concentrated nitric acid and concentrated sulfuric acid at a mass ratio of 1:3 for 6h at 60℃ to introduce carboxyl groups onto the surface of the carbon nanotubes to obtain carboxylated carbon nanotubes;

[0045] Secondly, a small amount of carboxylated carbon nanotubes were ultrasonically dispersed in 50ml of 1mol / L FeSO4 solution and 50ml of 1.75mol / L FeCl3 mixed solution, 1mol / L sodium hydroxide solution was added dropwise until Ph=12, the temperature was raised to 50℃, and heated for 3h, then 0.25g of sodium dodecyl sulfate was added, mixed uniformly, cooled to room temperature, and the black precipitate in the solution was collected by filtration, washed with deionized water until neutral, dried and ground to obtain a ferroferric oxide / carbon nanotube composite;

[0046] Then, 8wt% of the ferroferric oxide / carbon nanotube composite, 6wt% of the epoxy resin TDE-85, 2wt% of the polyether amine and 84wt% of the distilled water were stirred in a high-speed disperser at 3000rmp / min for 30min to prepare a Pickring emulsion adhesive;

[0047] 9mm, 6mm, 3mm chopped carbon fibers are mixed with a small amount of PEM, PEO and distilled water respectively to prepare several 0.077wt% carbon fiber slurries; carbon fiber raw paper is obtained by using a paper forming and paper making device to make paper; the carbon fiber raw paper is put into a Pickring nano emulsion, and the emulsion is demulsified by using an alternating magnetic field, so that resin nanoparticles and ferroferric oxide / carbon nanotube composites are precipitated and enter the fiber lap joints;

[0048] After the carbon paper raw paper is freeze-dried to remove water, it is hot-pressed under the conditions of a temperature of 90℃, a pressure of 5Mpa and a time of 60min, and the orientation structure of the magnetic conductive particles is controlled by a magnetic field; during solidification, on the one hand, the pressure causes the nano adhesive to break, and the adhesive components are solidified and bonded, and on the other hand, the conductive particles conduct the bonded carbon fibers, so that the bonded and conductive dual functions are realized to obtain a high-conductivity fuel cell gas diffusion layer carbon paper.

[0049] The carbon paper prepared by this method has a simple preparation method, a small amount of resin, low cost, good conductivity of 12.01mΩ·cm without carbonization and graphitization, high mechanical strength of 11.29MPa, and good thickness uniformity.

[0050] Example 3

[0051] First, the carbon nanotubes are ultrasonically treated in a mixture of concentrated nitric acid and concentrated sulfuric acid at a mass ratio of 1:3 at 60℃ for 6h to oxidize the carbon nanotubes and introduce carboxyl groups on the surface of the carbon nanotubes to obtain carboxylated carbon nanotubes;

[0052] Secondly, a small amount of carboxylated carbon nanotubes are ultrasonically dispersed in 50ml of a 1mol / L FeSO4 solution and 50ml of a 1.75mol / L FeCl3 solution and mixed, 1mol / L sodium hydroxide solution is added dropwise until Ph=12, the temperature is raised to 50℃, and heated for 3h, then 0.25g of sodium dodecyl sulfate is added, mixed uniformly, cooled to room temperature, and the black precipitate in the solution is collected by filtration, washed with deionized water until neutral, dried and ground to obtain a ferroferric oxide / carbon nanotube composite;

[0053] Then, 8wt% of the ferroferric oxide / carbon nanotube composite, 10wt% of epoxy resin E51, 2.5wt% of triethylenetetramine and 79.5wt% of distilled water are stirred at 3000rmp / min for 30min in a high-speed disperser to prepare a Pickring emulsion adhesive;

[0054] 9mm, 6mm, 3mm chopped carbon fibers are mixed with a small amount of PEM, PEO and distilled water respectively to prepare several 0.074wt% carbon fiber slurries; carbon fiber raw paper is obtained by using a paper forming and paper making device to make paper; the carbon fiber raw paper is put into a Pickring nano emulsion, and the emulsion is demulsified by using an alternating magnetic field, so that resin nanoparticles and ferroferric oxide / carbon nanotube composites are precipitated and enter the fiber lap joints;

[0055] After the carbon paper raw paper is freeze-dried to remove water, it is hot-pressed under the conditions of a temperature of 100°C, a pressure of 5Mpa and a time of 60min, and the orientation structure of the magnetic conductive particles is controlled by a magnetic field; during solidification, on the one hand, the pressure causes the nano adhesive to break, and the adhesive components are solidified and bonded, and on the other hand, the conductive particles conduct the bonded carbon fibers, so that the bonded and conductive dual functions are realized to obtain a high-conductivity fuel cell gas diffusion layer carbon paper.

[0056] The carbon paper prepared by this method has a simple preparation method, a small amount of resin, low cost, good conductivity of 13.73mΩ·cm without carbonization and graphitization, high mechanical strength of 10.34MPa, and good thickness uniformity.

[0057] Example 4

[0058] First, the carbon nanotubes are oxidized by ultrasonic treatment in a mixture of concentrated nitric acid and concentrated sulfuric acid at a mass ratio of 1:3 at 60°C for 6h to introduce carboxyl groups on the surface of the carbon nanotubes to obtain carboxylated carbon nanotubes;

[0059] Secondly, a small amount of carboxylated carbon nanotubes are ultrasonically dispersed in 50ml of 1mol / L FeSO4 solution and 50ml of 1.75mol / L FeCl3 solution and mixed, 1mol / L sodium hydroxide solution is added dropwise until Ph=12, the temperature is raised to 50°C, and heated for 3h, then 0.25g of sodium dodecyl sulfate is added, mixed uniformly, cooled to room temperature, and the black precipitate in the solution is collected by filtration, washed with deionized water until neutral, dried and ground to obtain a ferroferric oxide / carbon nanotube composite;

[0060] Then, 5wt% of the ferroferric oxide / carbon nanotube composite, 14.5wt% of the phenol formaldehyde resin prepolymer, 0.5wt% of cyclohexane and 80wt% of distilled water are stirred in a high-speed disperser at 3000rmp / min for 30min to prepare a Pickring emulsion adhesive;

[0061] 9mm, 6mm, 3mm pitch-based carbon fibers are mixed with a small amount of PEM, PEO and distilled water respectively to prepare several 0.067wt% carbon fiber slurries; carbon fiber raw paper is obtained by using a paper forming and paper making device to make paper, the carbon fiber raw paper is put into Pickring nano emulsion, and the emulsion is demulsified by using an alternating magnetic field, resin nanoparticles and ferroferric oxide / carbon nanotube composites are precipitated and enter the fiber lap joint points;

[0062] After the carbon paper raw paper is freeze-dried to remove water, it is hot-pressed under the conditions of a temperature of 170℃, a pressure of 5Mpa and a time of 60min, and the orientation structure of the magnetic conductive particles is controlled by a magnetic field; during solidification, on the one hand, the pressure causes the nano adhesive to break, the adhesive components to solidify and adhere, and on the other hand, the conductive particles conduct the adhered carbon fibers, realizing the adhesion and conductivity dual functions to obtain a high-conductivity fuel cell gas diffusion layer carbon paper.

[0063] The carbon paper prepared by this method has a simple preparation method, a small amount of resin, low cost, good conductivity of 19.27mΩ·cm without carbonization and graphitization, high mechanical strength of 9.89MPa and good thickness uniformity.

[0064] Example 5

[0065] First, the carbon nanotubes are oxidized by ultrasonic treatment in a mixture of concentrated nitric acid and concentrated sulfuric acid at a mass ratio of 1:3 for 6h at 60℃ to introduce carboxyl groups on the surface of the carbon nanotubes to obtain carboxylated carbon nanotubes;

[0066] Second, a small amount of carboxylated carbon nanotubes are ultrasonically dispersed in 50ml of 1mol / L FeSO4 solution and 50ml of 1.75mol / L FeCl3 solution and mixed, 1mol / L sodium hydroxide solution is added dropwise until Ph=12, the temperature is raised to 50℃, and heated for 3h, then 0.25g of sodium dodecyl sulfate is added, mixed uniformly, cooled to room temperature, and the black precipitate in the solution is collected by filtration, washed with deionized water until neutral, dried and ground to obtain a ferroferric oxide / carbon nanotube composite;

[0067] Then, 5wt% of the ferroferric oxide / carbon nanotube composite, 14.5wt% of the phenol formaldehyde resin prepolymer, 0.5wt% of cyclohexane and 80wt% of distilled water are stirred in a high-speed disperser at 3000rmp / min for 30min to prepare a Pickring emulsion adhesive;

[0068] 9mm, 6mm, 3mm chopped carbon fibers are mixed with a small amount of PEM, PEO and distilled water respectively to prepare several 0.067wt% carbon fiber slurries; carbon fiber raw paper is obtained by using a paper forming and paper making device; the carbon fiber raw paper is put into Pickring nano emulsion, and the emulsion is demulsified by using an alternating magnetic field; resin nanoparticles and ferroferric oxide / carbon nanotube composites are precipitated and enter the fiber lap joint points;

[0069] After the carbon paper raw paper is freeze-dried to remove water, it is hot-pressed under the conditions of a temperature of 170℃, a pressure of 5Mpa and a time of 60min, and the orientation structure of the magnetic conductive particles is controlled by a magnetic field; during solidification, on the one hand, the pressure causes the nano adhesive to break, and the adhesive components are solidified and bonded; on the other hand, the conductive particles conduct the bonded carbon fibers, realizing the bonding and conductive dual functions to obtain a high-conductivity fuel cell gas diffusion layer carbon paper.

[0070] The carbon paper prepared by this method has a simple preparation method, a small amount of resin, low cost, and good conductivity of 22.37mΩ·cm without carbonization and graphitization, and high mechanical strength of 13.28MPa.

Claims

1. A method for preparing carbon paper for a fuel cell gas diffusion layer, characterized in that: The method is: (1) Oxidizing carbon nanotubes under strong acid and ultrasonic conditions to obtain carboxylated carbon nanotubes; (2) Mixing carboxylated carbon nanotubes with a soluble salt solution containing divalent iron and trivalent iron, adding a small amount of sodium hydroxide solution, and preparing ferroferric oxide / carbon nanotube composites by coprecipitation method; (3) Mixing 5 wt% to 20 wt% of a ferroferric oxide / carbon nanotube composite, 5 wt% to 10 wt% of an adhesive, 0.5 wt% to 2 wt% of a resin diluent, and 70 wt% to 85 wt% of distilled water to prepare a Pickring emulsion adhesive; (4) dispersing carbon fibers in an aqueous solution containing a dispersant and a surfactant, preparing a carbon fiber slurry by beating, and making paper using a papermaking machine to obtain a carbon fiber base paper; wherein the dispersant is 0.10 wt% to 0.25 wt%, the surfactant is 0.01 wt% to 0.03 wt%, the carbon fibers are 0.01 wt% to 0.1 wt%, and the distilled water is 99.62 wt% to 99.77 wt%; (5) The carbon fiber base paper is immersed in the Pickring emulsion adhesive, and the emulsion particles are in situ demulsified by the action of an alternating magnetic field, so that the adhesive / ferroferric oxide / carbon nanotube composite particles are precipitated and adsorbed at the fiber overlap points by capillary action to obtain the carbon fiber bonded base paper; (6) The carbon fiber bonding base paper is dehydrated, the magnetic field is used to control the orientation of the magnetic conductive particles, and the hot pressing is performed in sequence to obtain the carbon paper for the fuel cell gas diffusion layer.

2. The method for preparing carbon paper for a fuel cell gas diffusion layer according to claim 1, wherein: In step (1), the strong acid is one or more of concentrated sulfuric acid, concentrated hydrochloric acid or concentrated nitric acid, the oxidation temperature is 50-100°C, and the time is 3-8 hours.

3. The method for preparing carbon paper for a fuel cell gas diffusion layer according to claim 1, wherein: In step (2), the divalent iron is ferrous sulfate or ferrous chloride, and the trivalent iron is ferric nitrate or ferric chloride; the concentration ratio of the divalent iron to the trivalent iron is 1:1.75, and the dosage ratio is 1:

1.

4. The method for preparing carbon paper for a fuel cell gas diffusion layer according to claim 1, wherein: In step (2), the heating temperature of the coprecipitation method is 30-80°C and the time is 2-6 h.

5. The method for preparing carbon paper for a fuel cell gas diffusion layer according to claim 1, wherein: In step (3), the adhesive is one or more of phenolic resin and epoxy resin; the resin diluent is one of n-hexane, triethylenetetramine or polyetheramine.

6. The method for preparing carbon paper for a fuel cell gas diffusion layer according to claim 1, wherein: In step (4), the length of the carbon fiber is one or more of 1 to 9 mm; and the mass fraction of the carbon fiber in the carbon fiber slurry is 0.05 wt% to 0.1 wt%.

7. The method for preparing carbon paper for a fuel cell gas diffusion layer according to claim 1, wherein: In step (4), the carbon fiber is one or more of polyacrylonitrile-based carbon fiber or asphalt-based carbon fiber; the surfactant is one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate or Tween-80; and the dispersant is one or more of polyethylene oxide, polyacrylamide, hydroxymethyl cellulose, and sodium hexametaphosphate.

8. The method for preparing carbon paper for a fuel cell gas diffusion layer according to claim 1, wherein: In step (6), the hot pressing treatment temperature is 80-180°C, the pressure is 2.5-10 MPa, and the time is 30-120 min.

9. A carbon paper for a fuel cell gas diffusion layer prepared by the preparation method according to any one of claims 1 to 8.

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