Carbon paper for fuel cell and preparation method thereof

Abstract

The present invention provides a carbon paper for fuel cells and a preparation method thereof, wherein the preparation method of the carbon paper comprises stirring and dispersing a conductive carbon material in a solvent to obtain a uniformly mixed dispersed solution; loading the dispersed solution on a non-woven fabric formed of polymer-based fibers, and obtaining a carbon paper sample after natural drying; stacking the carbon paper samples in multiple layers, and hot pressing the stacked carbon paper samples to obtain the carbon paper for fuel cells. The preparation process provided by the present invention is simple and low in cost; and the carbon paper prepared by the preparation method has good controllability in surface properties and mechanical properties.

Description

Technical Field

[0001] The invention belongs to the technical field of nano composite materials, and in particular relates to carbon paper for fuel cells and a preparation method thereof. Background Art

[0002] Fuel cells are an energy device that converts the chemical energy of fuel directly into electrical energy through electrochemical reactions. As a new type of energy device, fuel cells do not involve combustion in the reaction process, so the energy conversion efficiency is not limited by the Carnot cycle. They have significant characteristics such as high efficiency and cleanliness, and are the development trend of future energy.

[0003] In fuel cells, membrane electrodes account for 60% of the cost of proton exchange membrane fuel cells. Carbon paper, as a gas diffusion layer, is a key component of membrane electrodes, accounting for about 20% to 25% of the cost of the entire proton exchange membrane fuel cell. At present, foreign companies such as Japan's Toray, Germany's SGL, the United States' AvCarb, and Canada's Ballard have achieved large-scale production of gas diffusion layers, while domestic companies have not yet achieved large-scale production due to low market demand, immature technology and other reasons. Although the carbon paper currently produced is light in weight, has a smooth surface, is corrosion-resistant, has uniform pores and high strength, it is suitable for durable fuel cells. However, there are also obvious disadvantages. As a brittle material, carbon paper has small elastic deformation and is prone to cracks during installation. If not discovered in time, it will affect the safe use of fuel cells. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a carbon paper for fuel cells and a preparation method thereof, aiming to solve the problems of complex preparation process, poor mechanical properties and high production cost of traditional carbon paper.

[0005] In order to solve the above technical problems, the first aspect of the present invention provides a method for preparing carbon paper for fuel cells, the preparation method comprising:

[0006] The conductive carbon material is stirred and dispersed in a solvent to obtain a uniformly mixed dispersed solution;

[0007] The dispersed solution is loaded on a non-woven fabric formed of polymer-based fibers, and a carbon paper sample is obtained after drying;

[0008] The carbon paper samples are stacked in multiple layers, and the stacked carbon paper samples are subjected to heat pressing treatment to obtain the carbon paper for fuel cells.

[0009] Furthermore, the conductive carbon material includes one or more of conductive carbon black, graphite powder, carbon nanotubes, acetylene black, graphite emulsion, and activated carbon.

[0010] Furthermore, the polymer-based fiber includes any one of polypropylene fiber, polyethylene terephthalate fiber and polyethylene fiber.

[0011] Furthermore, the solvent includes any one of an aqueous solution, an N-methylpyrrolidone solution, and an ethanol solution.

[0012] Furthermore, the loading treatment includes any one of spraying, coating, adsorption and impregnation.

[0013] Furthermore, the temperature of the hot pressing treatment is 120-400° C., the pressure is 3-300 MPa, and the time is 5-60 min.

[0014] Furthermore, the number of stacked layers of the carbon paper sample is between 2 and 6.

[0015] A second aspect of the present invention provides a carbon paper for a fuel cell, which is prepared by the method for preparing the carbon paper for a fuel cell as described above.

[0016] Compared with the prior art, the carbon paper for fuel cells and the preparation method thereof provided in the present invention have the following beneficial effects:

[0017] Non-woven fabrics made of polymer-based fibers and composite conductive carbon through hot pressing can replace the carbon paper currently used in fuel cells, and the process is simple and low-cost. Since the surface of polymer-based fiber materials can be modified by different methods, the surface properties and mechanical properties of the carbon paper for fuel cells prepared by this process have good controllability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the preparation process of carbon paper for fuel in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] Carbon paper is an important raw material for preparing capacitors and electrocatalytic electrodes, and is also one of the key materials for preparing the gas diffusion layer of metal-air batteries. At present, the widely used carbon paper is mainly prepared through processes such as carbon fiber gluing papermaking, composite resin, hot pressing curing molding, and high-temperature carbonization. The preparation process is relatively cumbersome and the process conditions are relatively harsh. At the same time, the cumbersome preparation process also increases the cost of carbon paper. According to market research reports, the cost of carbon paper accounts for about 25% of the total cost of the battery. Therefore, how to efficiently prepare high-performance and low-cost carbon paper can promote the development and application of batteries and effectively contribute to the realization of the "dual carbon goals".

[0021] A first aspect of an embodiment of the present invention provides a method for preparing carbon paper for a fuel cell, such as Figure 1 The preparation method of carbon paper for fuel cells shown in the flowchart includes:

[0022] Step 101, stirring and dispersing the conductive carbon material in a solvent to obtain a uniformly mixed dispersed solution.

[0023] The conductive carbon material includes one or more of conductive carbon black, graphite powder, carbon nanotubes, acetylene black, graphite emulsion, activated carbon, etc. In the present invention, in particular, it is preferred to use a conductive carbon material containing conductive carbon black and / carbon nanotubes, and it is more preferred to use a conductive carbon material containing conductive carbon black / carbon nanotubes alone.

[0024] Carbon nanotubes have good mechanical properties, electrical properties and heat transfer properties, which make carbon nanotubes have a broad application market. Carbon nanotubes are generally prepared by arc discharge, laser ablation, chemical vapor deposition, solid phase pyrolysis, glow discharge, gas combustion and polymerization reaction synthesis. In the present invention, carbon nanotubes can be prepared by any method and are not specifically limited here.

[0025] The solvent may include, for example, water, halogenated hydrocarbons, ethers, amides, ketones, alcohols and the like; wherein ether solutions include tetrahydrofuran (THF), diethyl ether, 1,2-dimethoxyethane (DME) and the like; halogenated hydrocarbon solutions include dichloromethane, chloroform, 1,2-dichloroethane and the like; amide solutions include N,N-dimethylformamide (DMF), N-methylpyrrolidone solution, N-methyl-2-pyrrolidone (NMP) and the like; ketone solutions include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and the like; alcohol solutions include methanol, ethanol, isopropanol and the like; the above solvents may be used alone or in combination of two or more.

[0026] The conductive carbon material and the above solvent are stirred and mixed by a corresponding stirring device, and the stirring rate and stirring time are set accordingly to obtain a uniformly mixed dispersed solution. The concentration of carbon nanotubes in the dispersed solution can be set according to the required performance.

[0027] Step 102, loading the dispersed solution onto a non-woven fabric formed of polymer-based fibers, and obtaining a carbon paper sample after drying.

[0028] Among them, polymer-based fibers include polypropylene fibers, polyethylene terephthalate, polyethylene fibers and other materials. The surface of non-woven fabrics prepared using polymer-based fibers can be modified by different methods. The surface properties and mechanical properties of carbon paper prepared by this process have good controllability.

[0029] The loading treatment includes any one of spraying, coating, adsorption and impregnation. Through these treatment methods, the dispersed solution can penetrate into the gaps of the fibers, the initial speed given by the machine can be used to reduce the interfacial gap, and direct bonding can be achieved through extrusion and other means.

[0030] In the present invention, it is preferred to use a coating device to coat the dispersed solution and set a fixed scraper gap to form a coating layer of fixed thickness; after coating, the non-woven fabric formed by polymer-based fibers coated with the dispersed solution is placed in an oven, or in a natural environment, and based on the volatile nature of the solvent, the solvent is removed after drying, and a carbon paper sample coated with a conductive carbon material is formed on the surface of the non-woven fabric after drying.

[0031] Step 103, stacking the carbon paper samples in multiple layers, and subjecting the stacked carbon paper samples to a heat pressing process to obtain carbon paper for fuel cells.

[0032] The carbon paper samples are placed in a mold of a certain size for stacking, the number of stacking layers can be 2 to 6, and the preferred mold size is 90×90×0.5 mm. The mold is then subjected to a certain heat pressing process on a molding machine to prepare carbon paper for fuel cells.

[0033] In some embodiments, the parameters in the hot pressing process are set as follows: hot pressing temperature 120-400°C; hot pressing pressure 3-300 MPa; hot pressing time 5-60 min. The fuel cell carbon paper completed by hot pressing can be further formed into a fixed size by a cutting process.

[0034] The second aspect of the embodiment of the present invention provides a fuel cell carbon paper, which is prepared by the preparation method of the fuel cell carbon paper provided by the first aspect, wherein the main materials include a non-woven fabric made of polymer-based fibers and a conductive carbon material, and the prepared carbon paper has a thickness of 0.1 to 0.4 mm and a volume density of 0.3 to 0.8 g / cm 3 The porosity is 60% to 90%, the thickness direction resistance is 2 to 8Ω, the plane direction resistivity is 50 to 200mΩ·cm, and the moisture permeability is 80 to 90g / (m 2 h); has good electrical conductivity and mechanical properties. It can replace the cumbersome traditional carbon paper preparation process, reduce the cost of carbon paper production, promote the development and application of batteries, and effectively help achieve the "dual carbon goals".

[0035] The following is a specific example of the preparation of the carbon paper for fuel of the present invention. It should be noted that the conductive carbon materials used in the examples of the present invention are all carbon nanotubes, which are only given as examples.

[0036] Example 1

[0037] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, two layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 120°C, a hot pressing pressure of 3MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0038] The thickness of the carbon paper is 0.3 mm and the volume density is 0.5 g / cm 3 The porosity is 80%, the thickness direction resistance is 5Ω, the plane direction resistivity is 120mΩ·cm, and the moisture permeability is 82g / (m 2 h).

[0039] Example 2

[0040] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, two layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 130°C, a hot pressing pressure of 3MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0041] The thickness of the carbon paper is 0.3 mm and the volume density is 0.5 g / cm 3 The porosity is 83%, the thickness direction resistance is 6Ω, the plane direction resistivity is 180mΩ·cm, and the moisture permeability is 80g / (m 2 h).

[0042] Example 3

[0043] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, two layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 140°C, a hot pressing pressure of 3MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0044] The thickness of the carbon paper is 0.3 mm and the volume density is 0.6 g / cm 3 The porosity is 74%, the thickness direction resistance is 7Ω, the plane direction resistivity is 200mΩ·cm, and the moisture permeability is 85g / (m 2 h).

[0045] Example 4

[0046] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, two layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 150°C, a hot pressing pressure of 3MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0047] The thickness of the carbon paper is 0.4 mm and the volume density is 0.6 g / cm 3 The porosity is 76%, the thickness direction resistance is 5Ω, the plane direction resistivity is 170mΩ·cm, and the moisture permeability is 80g / (m 2 h).

[0048] Example 5

[0049] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, two layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 170°C, a hot pressing pressure of 3MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0050] The thickness of the carbon paper is 0.2 mm and the volume density is 0.4 g / cm 3 The porosity is 70%, the thickness direction resistance is 6Ω, the plane direction resistivity is 120mΩ·cm, and the moisture permeability is 81g / (m 2 h).

[0051] Example 6

[0052] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, the three layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 120°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0053] The thickness of the carbon paper is 0.2 mm and the volume density is 0.3 g / cm 3 The porosity is 63%, the thickness direction resistance is 5Ω, the plane direction resistivity is 59mΩ·cm, and the moisture permeability is 86g / (m 2 h).

[0054] Example 7

[0055] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, the three layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 130°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0056] The thickness of the carbon paper is 0.2 mm and the volume density is 0.3 g / cm 3 The porosity is 60%, the thickness direction resistance is 3Ω, the plane direction resistivity is 54mΩ·cm, and the moisture permeability is 85g / (m 2 h).

[0057] Example 8

[0058] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, the three layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 150°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0059] The thickness of the carbon paper is 0.2 mm and the volume density is 0.4 g / cm 3 The porosity is 80%, the thickness direction resistance is 3Ω, the plane direction resistivity is 90mΩ·cm, and the moisture permeability is 85g / (m 2 h).

[0060] Example 9

[0061] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, the three layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 170°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0062] The thickness of the carbon paper is 0.1 mm and the volume density is 0.3 g / cm 3 The porosity is 63%, the thickness direction resistance is 2Ω, the plane direction resistivity is 80mΩ·cm, and the moisture permeability is 80g / (m 2 h).

[0063] Example 10

[0064] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, four layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 120°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0065] The thickness of the carbon paper is 0.4 mm and the volume density is 0.8 g / cm 3 The porosity is 90%, the thickness direction resistance is 7Ω, the plane direction resistivity is 200mΩ·cm, and the moisture permeability is 90g / (m 2 h).

[0066] Embodiment 11

[0067] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, four layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 130°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0068] The thickness of the carbon paper is 0.4 mm and the volume density is 0.7 g / cm 3 The porosity is 87%, the thickness direction resistance is 8Ω, the plane direction resistivity is 180mΩ·cm, and the moisture permeability is 89g / (m 2 h).

[0069] Example 12

[0070] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, four layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 140°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0071] The thickness of the carbon paper is 0.4 mm and the volume density is 0.7 g / cm 3 The porosity is 90%, the thickness direction resistance is 6Ω, the plane direction resistivity is 150mΩ·cm, and the moisture permeability is 86g / (m 2 h).

[0072] Example 13

[0073] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, four layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 150°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0074] The thickness of the carbon paper is 0.3 mm and the volume density is 0.7 g / cm 3 The porosity is 86%, the thickness direction resistance is 8Ω, the plane direction resistivity is 170mΩ·cm, and the moisture permeability is 86g / (m 2 h).

[0075] Embodiment 14

[0076] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, four layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 170°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0077] The thickness of the carbon paper is 0.4 mm and the volume density is 0.7 g / cm 3 The porosity is 87%, the thickness direction resistance is 8Ω, the plane direction resistivity is 180mΩ·cm, and the moisture permeability is 86g / (m 2 h).

[0078] Embodiment 15

[0079] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, 6 layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 120°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0080] The thickness of the carbon paper is 0.3 mm and the volume density is 0.6 g / cm 3 The porosity is 82%, the thickness direction resistance is 6Ω, the plane direction resistivity is 150mΩ·cm, and the moisture permeability is 84g / (m 2 h).

[0081] Example 16

[0082] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, 6 layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 130°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0083] The thickness of the carbon paper is 0.3 mm and the volume density is 0.6 g / cm 3 The porosity is 85%, the thickness direction resistance is 7Ω, the plane direction resistivity is 150mΩ·cm, and the moisture permeability is 89g / (m 2 h).

[0084] Embodiment 17

[0085] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, 6 layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 140°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0086] The thickness of the carbon paper is 0.3 mm and the volume density is 0.7 g / cm 3 The porosity is 76%, the thickness direction resistance is 6Ω, the plane direction resistivity is 140mΩ·cm, and the moisture permeability is 83g / (m 2 h).

[0087] Embodiment 18

[0088] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, 6 layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 150°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0089] The thickness of the carbon paper is 0.3 mm and the volume density is 0.6 g / cm 3 The porosity is 78%, the thickness direction resistance is 5Ω, the plane direction resistivity is 167mΩ·cm, and the moisture permeability is 86g / (m 2 h).

[0090] Embodiment 19

[0091] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, 6 layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 170°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0092] The thickness of the carbon paper is 0.2 mm and the volume density is 0.4 g / cm 3 The porosity is 70%, the thickness direction resistance is 6Ω, the plane direction resistivity is 80mΩ·cm, and the moisture permeability is 84g / (m 2 h).

[0093] Embodiment 20

[0094] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​ethylene fiber non-woven fabric. After natural drying, 6 layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 150°C, a hot pressing pressure of 10MPa, and a hot pressing time of 10min to prepare a shaped carbon paper.

[0095] The thickness of the carbon paper is 0.3 mm and the volume density is 0.5 g / cm 3 The porosity is 73%, the thickness direction resistance is 5Ω, the plane direction resistivity is 140mΩ·cm, and the moisture permeability is 85g / (m 2 h).

[0096] Embodiment 21

[0097] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​ethylene fiber non-woven fabric. After natural drying, 6 layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 120°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0098] The thickness of the carbon paper is 0.4 mm and the volume density is 0.8 g / cm 3 The porosity is 89%, the thickness direction resistance is 8Ω, the plane direction resistivity is 190mΩ·cm, and the moisture permeability is 90g / (m 2 h).

[0099] Embodiment 22

[0100] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​ethylene fiber non-woven fabric. After natural drying, 6 layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 150°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0101] The thickness of the carbon paper is 0.3 mm and the volume density is 0.8 g / cm 3 The porosity is 86%, the thickness direction resistance is 8Ω, the plane direction resistivity is 100mΩ·cm, and the moisture permeability is 90g / (m 2 h).

[0102] Embodiment 23

[0103] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​ethylene fiber non-woven fabric. After natural drying, 5 layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 130°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0104] The thickness of the carbon paper is 0.3 mm and the volume density is 0.8 g / cm 3 The porosity is 80%, the thickness direction resistance is 7Ω, the plane direction resistivity is 160mΩ·cm, and the moisture permeability is 90g / (m 2 h).

[0105] Embodiment 24

[0106] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polyethylene terephthalate fiber non-woven fabric. After natural drying, 6 layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 150°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0107] The thickness of the carbon paper is 0.3 mm and the volume density is 0.7 g / cm 3 The porosity is 80%, the thickness direction resistance is 7Ω, the plane direction resistivity is 170mΩ·cm, and the moisture permeability is 83g / (m 2 h).

[0108] Embodiment 25

[0109] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polyethylene terephthalate fiber non-woven fabric. After natural drying, 6 layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 130°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0110] The thickness of the carbon paper is 0.3 mm and the volume density is 0.5 g / cm 3 The porosity is 84%, the thickness direction resistance is 6Ω, the plane direction resistivity is 150mΩ·cm, and the moisture permeability is 88g / (m 2 h).

[0111] Embodiment 26

[0112] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polyethylene terephthalate fiber non-woven fabric. After natural drying, 5 layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 130°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0113] The thickness of the carbon paper is 0.4 mm and the volume density is 0.7 g / cm 3 The porosity is 76%, the thickness direction resistance is 8Ω, the plane direction resistivity is 190mΩ·cm, and the moisture permeability is 87g / (m 2 h).

[0114] Embodiment 27

[0115] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polypropylene non-woven fabric. After natural drying, the three layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 400°C, a hot pressing pressure of 3MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0116] The thickness of the carbon paper is 0.3 mm and the volume density is 0.6 g / cm 3 The porosity is 77%, the thickness direction resistance is 6Ω, the plane direction resistivity is 90mΩ·cm, and the moisture permeability is 82g / (m 2 h).

[0117] Embodiment 28

[0118] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polyethylene terephthalate fiber non-woven fabric. After natural drying, 5 layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 400°C, a hot pressing pressure of 10MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0119] The thickness of the carbon paper is 0.1 mm and the volume density is 0.5 g / cm 3 The porosity is 60%, the thickness direction resistance is 2Ω, the plane direction resistivity is 50mΩ·cm, and the moisture permeability is 80g / (m 2 h).

[0120] Embodiment 29

[0121] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polyethylene terephthalate fiber non-woven fabric. After natural drying, 5 layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 200°C, a hot pressing pressure of 300MPa, and a hot pressing time of 5min to prepare a shaped carbon paper.

[0122] The thickness of the carbon paper is 0.1 mm and the volume density is 0.3 g / cm 3 The porosity is 63%, the thickness direction resistance is 3Ω, the plane direction resistivity is 56mΩ·cm, and the moisture permeability is 82g / (m 2 h).

[0123] Embodiment 30

[0124] The coating equipment sets the scraper gap and coats the dispersed solution containing carbon nanotubes on a certain area of ​​polyethylene terephthalate fiber non-woven fabric. After natural drying, 5 layers of the obtained carbon paper samples are stacked and placed in a 90×90×0.5mm mold. Then, they are molded on a molding machine at a hot pressing temperature of 150°C, a hot pressing pressure of 200MPa, and a hot pressing time of 60min to prepare a shaped carbon paper.

[0125] The thickness of the carbon paper is 0.2 mm and the volume density is 0.3 g / cm 3 The porosity is 65%, the thickness direction resistance is 3Ω, the plane direction resistivity is 60mΩ·cm, and the moisture permeability is 81g / (m 2 h).

[0126] It should be noted that the present invention includes but is not limited to the above embodiments, and any equivalent replacement or partial improvement made under the spirit and principle of the present invention shall be deemed to be within the protection scope of the present invention.

[0127] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. 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 present invention.

Claims

1. A method for preparing carbon paper for fuel cells, characterized in that: The preparation method comprises: The conductive carbon material is stirred and dispersed in a solvent to obtain a uniformly mixed dispersed solution; wherein the solvent includes any one of an aqueous solution, an N-methylpyrrolidone solution, and an ethanol solution; The dispersed solution is loaded on a non-woven fabric formed of polymer-based fibers, and a carbon paper sample is obtained after drying; wherein the polymer-based fibers include any one of polypropylene fibers, polyethylene terephthalate fibers, and polyethylene fibers; and the loading treatment includes any one of spraying, coating, adsorption, and impregnation; The carbon paper samples are stacked in multiple layers, and the stacked carbon paper samples are subjected to heat pressing treatment to obtain the carbon paper for fuel cells; wherein the heat pressing treatment is performed at a temperature of 120 to 400 ºC, a pressure of 3 to 300 Mpa, and a time of 5 to 60 minutes.

2. The preparation method according to claim 1, characterized in that: The conductive carbon material includes one or more of conductive carbon black, graphite powder, carbon nanotubes, acetylene black, graphite emulsion, and activated carbon.

3. The preparation method according to claim 1, characterized in that: The number of stacked layers of the carbon paper sample is between 2 and 6.

4. A carbon paper for a fuel cell, characterized in that: The carbon paper is prepared by the method for preparing carbon paper for fuel cells as claimed in any one of claims 1 to 3.

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