A flexible three-dimensional porous carbon paper and a preparation method thereof, and a fuel cell

Abstract

The application discloses a flexible three-dimensional porous carbon paper and a preparation method and a fuel cell thereof. The method comprises the following steps: dispersing carbon nanotube slurry, carbon fiber slurry, graphene slurry and polytetrafluoroethylene slurry; mixing the carbon nanotube slurry, the carbon fiber slurry, the graphene slurry and the polytetrafluoroethylene slurry to form carbon paper mixed slurry according to a mass ratio of 1:(1-10):(0.1-10):1.5; adding the carbon paper mixed slurry into a vacuum filtration device, performing suction filtration after standing, and performing suction drying to form a flexible three-dimensional porous carbon paper sample; and performing vacuum drying on the flexible three-dimensional porous carbon paper sample, and performing high-temperature heat treatment to form the flexible three-dimensional porous carbon paper. The carbon paper prepared by the application has the characteristics of a three-dimensional porous structure, a three-dimensional conductive channel network and high battery performance. The flexible three-dimensional porous carbon paper can solve the practical application problems of the existing commercial carbon paper, such as many and uneven large pores on the surface, easy breakage when being bent, complicated process, high-temperature graphitization, large energy consumption and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fuel cell technology, in particular to a flexible three-dimensional porous carbon paper and a preparation method thereof. BACKGROUND

[0002] With the continuous depletion of global fossil energy, people have begun to look for new alternative energy sources. New energy represented by wind energy, solar energy, hydrogen energy, etc. has become a hot topic for many scientists. Due to the advantages of proton exchange membrane fuel cell (PEMFC) such as small system volume, high energy density and clean pollution-free, it has been highly valued by the energy industry. The core component of proton exchange membrane fuel cell (PEMFC) is membrane electrode (MEA), which is composed of gas diffusion layer, catalyst layer and proton exchange membrane. The gas diffusion layer (GDL) is between the catalyst layer and the bipolar plate, and its main function is to support the catalyst layer, collect the current, and provide gas channels, hydrophobic channels and electron transmission channels for the electrode reaction. Generally, the gas diffusion layer is usually composed of a large-pore support layer and a microporous layer, and the substrate of the support layer is mainly composed of porous materials such as carbon fiber paper, and the microporous layer is composed of carbon powder and hydrophobic polytetrafluoroethylene (PTFE). Therefore, the main parameters of a good or bad gas diffusion layer performance are conductivity and drainage.

[0003] Carbon paper is widely used as a gas diffusion layer. At present, in the case of certain carbon paper conductivity, in order to meet the carbon paper drainage and conductivity, the carbon paper substrate is usually impregnated with PTFE emulsion to solve the problem; this process is relatively complicated, but there are still problems such as low porosity, unsatisfactory gas channel, rapid decline of battery performance under high current discharge, and the like. In addition, under the long-term operation environment of the fuel cell, the carbon black material will also gradually oxidize, causing the microporous layer to become hydrophilic, increasing the mass transfer polarization, and greatly shortening the service life of the battery. At present, the substrate material commonly used for fuel cell gas diffusion layer at home and abroad is still carbon fiber paper. However, the disadvantage of carbon fiber paper is poor bending mechanical property, and under the conditions of battery MEA assembly pressure, external collision and repeated disassembly, fiber fracture, substrate cracking, fiber and substrate interface peeling and the like are easy to occur, thereby affecting the service life of the battery MEA. SUMMARY

[0004] In view of the problems existing in the prior art, one of the purposes of the present application is to provide a flexible three-dimensional porous carbon paper with a three-dimensional porous structure, which improves the porosity of the carbon paper, thereby reducing the rapid decline of the battery performance caused by "water flooding" in the high current test of the fuel cell.

[0005] The second purpose of the present application is to provide a preparation method of the flexible three-dimensional porous carbon paper.

[0006] A third object of the present application is to provide a flexible three-dimensional porous carbon paper prepared by the above method.

[0007] A fourth object of the present application is to provide a fuel cell comprising the flexible three-dimensional porous carbon paper of the third aspect.

[0008] To achieve the above object, the first aspect of the present application provides a flexible three-dimensional porous carbon paper comprising carbon nanotube slurry m1g, carbon fiber slurry m2g, graphene slurry m3g and polytetrafluoroethylene slurry m4g, wherein the mass ratio of the carbon nanotube slurry, the carbon fiber slurry, the graphene slurry and the polytetrafluoroethylene slurry is m1:m2:m3:m4=1:(1-10):(0.1-10):1.5.

[0009] Further, the concentration of the carbon nanotube slurry is 0.1 mg / ml.

[0010] Further, the concentration of the carbon fiber slurry is 1 mg / ml.

[0011] Further, the concentration of the graphene slurry is 0.05 mg / ml.

[0012] Further, the concentration of the polytetrafluoroethylene slurry is 0.06 mg / ul.

[0013] The second aspect of the present application provides a preparation method of a flexible three-dimensional porous carbon paper, comprising the following steps:

[0014] dispersing carbon nanotube slurry, carbon fiber slurry, graphene slurry and polytetrafluoroethylene slurry;

[0015] mixing the carbon nanotube slurry, the carbon fiber slurry, the graphene slurry and the polytetrafluoroethylene slurry according to the mass ratio 1:(1-10):(0.1-10):1.5 to form a carbon paper mixed slurry;

[0016] adding the carbon paper mixed slurry into a vacuum filtration device, and after standing, performing suction filtration, and then suction drying the slurry to form a flexible three-dimensional porous carbon paper sample;

[0017] After vacuum drying the flexible three-dimensional porous carbon paper sample, high-temperature heat treatment is performed to form a flexible three-dimensional porous carbon paper.

[0018] Further, dispersing the carbon nanotube slurry comprises:

[0019] Weighing carbon nanotube powder into a beaker;

[0020] Weighing one or more of sulfonic acid, polyethylene glycol (PEG), sodium dodecyl sulfate (SDS), Igepal CO-880 (IGP) and cetyltrimethylammonium bromide (CTAB) into the beaker;

[0021] The pure water is added into the cell pulverizer after mixing in the beaker for 30-90 min at 10 DEG C.

[0022] Further, the dispersed carbon fiber slurry comprises:

[0023] The carbon fiber powder is weighed and placed in a beaker;

[0024] The pure water is measured and added into the beaker;

[0025] One or more of methanol, ethanol, propanol, isopropanol, ethylene glycol, glycerol, and cyclohexanol is measured and added into the beaker;

[0026] The acetone is measured and added into the beaker after mixing for 2-20 min at room temperature in the ultrasonic machine.

[0027] Further, the dispersed graphene slurry comprises:

[0028] The graphene powder is weighed and placed in a beaker;

[0029] One or more of sulfonic acid, polyethylene glycol (PEG), sodium dodecyl sulfate (SDS), IGP, and cetyltrimethylammonium bromide (CTAB) is weighed and added into the beaker;

[0030] The pure water is added into the cell pulverizer after mixing in the beaker for 30-90 min at 10 DEG C.

[0031] The third aspect of the present application provides a flexible three-dimensional porous carbon paper prepared by the preparation method of the second aspect.

[0032] The fourth aspect of the present application provides a fuel cell comprising the flexible three-dimensional porous carbon paper of the third aspect.

[0033] The present application prepares a flexible three-dimensional porous carbon paper by carbon nanotube slurry, carbon fiber slurry, graphene slurry, and polytetrafluoroethylene slurry according to a specific ratio, and the three-dimensional porous structure is built by mixing the various materials together, so that the carbon paper film is always in a high porosity, thereby reducing the rapid decline of the battery performance caused by "water flooding" in the high current test of the fuel cell, and the carbon paper has a high bending mechanical strength and increased flexibility.

[0034] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. DETAILED DESCRIPTION

[0035] The exemplary embodiments will now be described more fully. However, the exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the invention will be more comprehensive and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art.

[0036] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0037] The first aspect of the present invention provides a flexible three-dimensional porous carbon paper, comprising carbon nanotube slurry m1g, carbon fiber slurry m2g, graphene slurry m3g and polytetrafluoroethylene slurry m4g, wherein the mass ratio of carbon nanotube slurry, carbon fiber slurry, graphene slurry and polytetrafluoroethylene slurry m1:m2:m3:m4 = 1:(1~10):(0.1~10):1.5.

[0038] Optionally, the concentration of the carbon nanotube slurry is 0.1–1 mg / ml.

[0039] Optionally, the concentration of the carbon fiber slurry is 0.5 to 3 mg / ml.

[0040] Optionally, the concentration of the graphene slurry is 0.01 to 1 mg / ml.

[0041] Optionally, the concentration of the polytetrafluoroethylene slurry is 0.01–0.08 mg / μL.

[0042] A second aspect of the present invention provides a method for preparing flexible three-dimensional porous carbon paper, comprising the following steps:

[0043] Dispersed carbon nanotube slurry, carbon fiber slurry, graphene slurry, and polytetrafluoroethylene slurry;

[0044] Carbon nanotube slurry, carbon fiber slurry, graphene slurry, and polytetrafluoroethylene slurry are mixed in a mass ratio of 1:(1-10):(0.1-10):1.5 to form a carbon-paper mixed slurry;

[0045] The carbon paper mixture was added to a vacuum filtration device, allowed to stand, and then filtered to dry the mixture, forming a flexible three-dimensional porous carbon paper sample.

[0046] Flexible three-dimensional porous carbon paper samples are vacuum dried and then subjected to high-temperature heat treatment to form flexible three-dimensional porous carbon paper.

[0047] Optionally, the dispersed carbon nanotube slurry comprises:

[0048] Weigh the carbon nanotube powder into a beaker;

[0049] Weigh one or more of sulfonic acid, polyethylene glycol (PEG), sodium dodecyl sulfate (SDS), Igepal CO- 720 (IGP), and cetyltrimethylammonium bromide (CTAB) into the beaker;

[0050] After adding pure water into the beaker and mixing uniformly, the mixture is added into a cell crusher, and dispersed at 10℃ for 30-90 min.

[0051] Optionally, the dispersed carbon fiber slurry comprises:

[0052] Weigh the carbon fiber powder into a beaker;

[0053] Weigh pure water into the beaker;

[0054] Weigh one or more of methanol, ethanol, propanol, isopropanol, ethylene glycol, glycerol, and cyclohexanol into the beaker;

[0055] Weigh acetone into the beaker, mix uniformly, and then add into an ultrasonic machine, and dispersed at room temperature for 2-20 min.

[0056] Further, the dispersed graphene slurry comprises:

[0057] Weigh the graphene powder into a beaker;

[0058] Weigh one or more of sulfonic acid, polyethylene glycol (PEG), sodium dodecyl sulfate (SDS), Igepal CO- 720 (IGP), and cetyltrimethylammonium bromide (CTAB) into the beaker;

[0059] After adding pure water into the beaker and mixing uniformly, the mixture is added into a cell crusher, and dispersed at 10℃ for 30-90 min.

[0060] The third aspect of the present application provides a flexible three-dimensional porous carbon paper prepared by the preparation method of the second aspect.

[0061] The fourth aspect of the present application provides a fuel cell comprising the flexible three-dimensional porous carbon paper of the third aspect.

[0062] Example 1:

[0063] 1. Dispersed carbon nanotube (CNT) slurry, carbon fiber (CF) slurry, and graphene slurry

[0064] 1) Dispersing carbon nanotube (CNT) slurry specifically includes: take: CNT powder: 100 mg, placed in a 1000 ml beaker; take sulfonic acid, polyethylene glycol (PEG), sodium dodecyl sulfate (SDS), IGP and cetyltrimethylammonium bromide (CTAB) and other one or several: 1000 mg, also added to the 1000 ml beaker containing CNT powder; take pure water: 1000 ml; add in three times, one side adds a glass rod stirring, the three are initially mixed evenly; finally the three mixed slurry into the cell crusher under certain power at room temperature for several hours.

[0065] 2) Dispersing carbon fiber (CF) slurry specifically includes: take: CF powder: 100 mg, placed in a 250 ml beaker; take pure water: 50 ml, also added to the 250 ml beaker containing CF powder; take methanol, ethanol, propanol, isopropanol, ethylene glycol, glycerol, cyclohexanol one or several: 25 ml, added to the above 250 ml beaker; take acetone: 25 ml, added to the above 250 ml beaker; then use a glass rod to stir the mixture evenly; finally the mixed slurry beaker mouth with plastic wrap and rubber band seal; added to the digital ultrasonic machine, certain power at room temperature for several hours.

[0066] 3) Dispersing graphene slurry specifically includes: take: graphene powder: 50 mg, placed in a 1000 ml beaker; take sulfonic acid, polyethylene glycol (PEG), sodium dodecyl sulfate (SDS), IGP and cetyltrimethylammonium bromide (CTAB) and other one or several: 1000 mg, also added to the 1000 ml beaker containing graphite powder; take pure water 1000 ml; add in three times, one side adds a glass rod stirring, the three are initially mixed evenly; finally the three mixed slurry into the cell crusher under certain power at room temperature for several hours.

[0067] 2, Preparation of carbon paper mixed slurry

[0068] 1) The effective composition of carbon paper mixed slurry: CNT, CF, polytetrafluoroethylene (PTFE), graphene; The content of each part of the carbon paper mixed slurry is: take 0.1 mg / ml CNT slurry: m1 g, take 1 mg / ml CF slurry: m2 g, take 0.05 mg / ml graphene slurry: m3 g, take 0.06 mg / ul PTFE: m4 g, the mass ratio of the four is: m1: m2: m3: m4 = 1: (1-10): (0.1-10): 1.5 between the mass ratio mixed to form the mixed slurry.

[0069] 2) The carbon paper mixed slurry is prepared and added to a beaker, which is placed in an ultrasonic machine, and dispersed at room temperature for several minutes at a certain power to prepare a uniform mixed slurry.

[0070] 3. Preparation of flexible three-dimensional porous carbon paper

[0071] 1) The uniform mixed slurry is added to a vacuum filtration device, and after standing for a while, the slurry is filtered and dried to directly form a flexible three-dimensional porous carbon paper sample.

[0072] 2) After vacuum drying, the flexible three-dimensional porous carbon paper sample is heat treated at a high temperature of 200-500°C to form a flexible three-dimensional porous carbon paper that can be used for high-performance PEMFC.

[0073] The flexible three-dimensional porous carbon paper prepared by the above method has the following morphological characteristics at different SEM scales in the same area. The specific details are that a-i are the porous structures of the surface morphology characteristics in the range of 100 μm-0.5 μm magnification. It can be seen from the pore structure characteristics that the carbon paper has the following characteristics:

[0074] 1. The carbon fibers have the function of building the overall macroporous framework in the entire carbon paper, and can act as the "macroporous skeleton" of the carbon paper. In the compression process of the carbon paper, it can maintain the three-dimensional porous structure of the carbon paper and reduce the occurrence of closed pores.

[0075] 2. The carbon nanotubes, mesoporous carbon, graphene and other nanomaterials are filled in the carbon fiber porous "skeleton", and a new mesoporous network is established. The carbon nanotubes, wrapped graphene and hydrophobic agents and other materials form a three-dimensional porous structure in the mesoporous system, which can ensure that the porosity of the carbon paper is maintained at a high level, which is conducive to the air permeability of the carbon paper.

[0076] 3. The carbon nanotubes, graphene and other high-conductivity materials added in the three-dimensional conductive network of the carbon fibers can again "build" more conductive "bridge" network channels, ensuring that the electron transmission is maintained at a high level, which can reduce the internal resistance of the carbon paper.

[0077] 4. The one or more hydrophobic agents such as polytetrafluoroethylene, fluorinated ethylene propylene copolymer and polyvinylidene fluoride emulsion are added around the mesopores, and after heat treatment, they are mixed with carbon fibers, carbon nanotubes, graphene and other materials to jointly build a three-dimensional porous structure. This three-dimensional porous carbon paper forms a hydrophobic coating around the porous interior, allowing liquid in the porous network to quickly overflow from the interior, ensuring that the interior of the carbon paper film is always at a high porosity, thereby reducing the "flooding" of the fuel cell during high-current testing, which causes the performance of the fuel cell to rapidly decrease.

[0078] 5. One or more hydrophobic agents of carbon nanotubes, graphene, polytetrafluoroethylene, fluorinated ethylene propylene copolymer, and polyvinylidene fluoride emulsion, and carbon fibers are wound inside to form a three-dimensional porous structure network carbon paper, which can have high bending mechanical strength and increase the flexibility of the carbon paper.

[0079] In this study, the carbon paper and the commercial carbon paper were made into MEA, and the polarization curve and the battery power density curve were tested under the same battery test conditions. The test conditions were room temperature, certain back pressure, and RH% = 100% MEA test results. From the overall MEA polarization curve analysis, the MEA made of the carbon paper in this study has obvious advantages in ohmic polarization, and the limiting current can reach 1800 mA / cm 2 The peak power can reach 700 mW / cm 2 Around.

[0080] Example 2:

[0081] 1. Disperse carbon nanotube (CNT) slurry, carbon fiber (CF) slurry and graphene slurry

[0082] 1) Disperse carbon nanotube (CNT) slurry specifically includes: take CNT powder: 200 mg, put in 1000 ml beaker; Take sulfonic acid, polyethylene glycol (PEG), sodium dodecyl sulfate (SDS), IGP and cetyltrimethylammonium bromide (CTAB) and one or more: 1000 mg, also added to the 1000 ml beaker containing CNT powder; Measure pure water: 1000 ml; Add in three times, stir with a glass rod while adding, mix the three uniformly; Finally, the mixed slurry of the three is added to the cell crusher and dispersed for several hours at room temperature and certain power.

[0083] 2) Disperse carbon fiber (CF) slurry specifically includes: take CF powder: 200 mg, put in 250 ml beaker; Measure pure water: 50 ml, also added to the 250 ml beaker containing CF powder; Measure methanol, ethanol, propanol, isopropanol, ethylene glycol, glycerol, cyclohexanol one or more: 25 ml, added to the above 250 ml beaker; Measure acetone: 25 ml, added to the above 250 ml beaker; Then stir the mixture with a glass rod; Finally, the mouth of the mixed slurry beaker is sealed with plastic wrap and rubber band; Add to the digital ultrasonic machine, disperse for several hours at room temperature and certain power.

[0084] 3) The dispersion of graphene slurry specifically includes: weighing: graphene powder: 40 mg, placed in a 1000 ml beaker; weigh one or several kinds of sulfonic acid, polyethylene glycol (PEG), sodium dodecyl sulfate (SDS), IGP and cetyltrimethylammonium bromide (CTAB): 1000 mg, also added to the 1000 ml beaker containing the graphite powder at one time; measure 1000 ml of pure water; add in three times, stir with a glass rod while adding, and mix the three uniformly; finally, the mixed slurry of the three is added to the cell crusher and dispersed at room temperature for several hours.

[0085] 2) Preparation of carbon paper mixed slurry

[0086] 1) The effective composition of the carbon paper mixed slurry is: CNT, CF, polytetrafluoroethylene (PTFE), graphene; the content of each part of the carbon paper mixed slurry is: take 0.2 mg / ml CNT slurry: m1 g, take 2 mg / ml CF slurry: m2 g, take 0.04 mg / ml graphene slurry: m3 g, take 0.06 mg / ul PTFE: m4 g, the mass ratio of the four is: m1:m2:m3:m4=1:(1-10):(0.1-10):1.5 mass ratio mixed to form the mixed slurry.

[0087] 2) The prepared carbon paper mixed slurry is added to a beaker and placed in an ultrasonic machine for dispersion at room temperature for several minutes to prepare a uniform mixed slurry.

[0088] 3) Preparation of flexible three-dimensional porous carbon paper

[0089] 1) The uniform mixed slurry is added to a vacuum filtration device and filtered after standing for a while. The slurry is dried by suction to directly form a flexible three-dimensional porous carbon paper sample.

[0090] 2) After vacuum drying, the flexible three-dimensional porous carbon paper sample is heat treated at a high temperature of 200-500°C to form a flexible three-dimensional porous carbon paper that can be used for high-performance PEMFC.

[0091] The flexible three-dimensional porous carbon paper prepared by the above method has the following morphological characteristics at different SEM scales in the same area. The specific details are that a-i, the porous structure of the surface morphology in the range of 100 μm-0.5 μm magnification. From the pore structure characteristics, it can be seen that the carbon paper has the following characteristics:

[0092] 1. Carbon fibers have the function of building the overall macroporous framework in the entire carbon paper, which can act as the "macroporous skeleton" of the carbon paper. During the compression of the carbon paper, it can maintain the three-dimensional porous structure of the carbon paper and reduce the occurrence of closed pores.

[0093] 2. Carbon nanotubes, mesoporous carbon, graphene and other nanomaterials are filled in the porous "skeleton" of carbon fibers, and a new mesoporous network is established. Among them, carbon nanotubes and wrapped graphene and hydrophobic agents and other materials form a three-dimensional porous structure in the mesoporous system, which can ensure that the porosity of the carbon paper is maintained at a high level, which is beneficial to the air permeability of the carbon paper.

[0094] 3. Carbon nanotubes, graphene and other high-conductivity materials are added to the three-dimensional conductive network of carbon fibers, which can "build" more conductive "bridge" network channels, ensuring that the electron transmission is maintained at a high level, and the internal resistance of the carbon paper can be reduced.

[0095] 4. Add one or more hydrophobic agents such as polytetrafluoroethylene, fluorinated ethylene propylene copolymer, and polyvinylidene fluoride emulsion around the mesoporous. After heat treatment, it will mix with carbon fibers, carbon nanotubes, graphene and other materials to build a three-dimensional porous structure. This three-dimensional porous carbon paper forms a hydrophobic coating around the porous interior, allowing liquid in the porous network to quickly overflow from the interior, ensuring that the carbon paper film always has a high porosity, thereby reducing the "waterlogging" that causes rapid performance decline in high-current testing of fuel cells.

[0096] 5. Carbon nanotubes, graphene, polytetrafluoroethylene, fluorinated ethylene propylene copolymer, and one or more hydrophobic agents such as polyvinylidene fluoride emulsion, and carbon fibers are wound inside to form a three-dimensional porous structure network carbon paper, which can have high bending mechanical strength and increase the flexibility of the carbon paper.

[0097] In this study, the carbon paper and the commercial carbon paper were made into MEA, and the polarization curve and the battery power density curve were tested under the same battery test conditions. The test conditions were room temperature, certain back pressure, RH% = 100% MEA test results. From the overall MEA polarization curve analysis, the MEA made of carbon paper in this study has obvious advantages in ohmic polarization, and the limiting current can reach 1800mA / cm 2 The peak power can reach 700mW / cm 2 .

[0098] Example 3:

[0099] 1. Disperse carbon nanotube (CNT) slurry, carbon fiber (CF) slurry and graphene slurry

[0100] 1) Dispersing carbon nanotube (CNT) slurry specifically includes: take: CNT powder: 300 mg, placed in a 1000 ml beaker; take sulfonic acid, polyethylene glycol (PEG), sodium dodecyl sulfate (SDS), IGP and cetyltrimethylammonium bromide (CTAB) and other one or several: 1000 mg, also added to the 1000 ml beaker containing CNT powder; take pure water: 1000 ml; add in three times, one side adds a glass rod stirring, the three are initially mixed evenly; finally the three mixed slurry into the cell crusher under certain power at room temperature for several hours.

[0101] 2) Dispersing carbon fiber (CF) slurry specifically includes: take: CF powder: 300 mg, placed in a 250 ml beaker; take pure water: 50 ml, also added to the 250 ml beaker containing CF powder; take methanol, ethanol, propanol, isopropanol, ethylene glycol, glycerol, cyclohexanol one or several: 25 ml, added to the above 250 ml beaker; take acetone: 25 ml, added to the above 1000 ml beaker; then the mixture is stirred evenly with a glass rod; finally the mixed slurry beaker is sealed with plastic wrap and rubber band; added to the digital ultrasonic machine, certain power at room temperature for several hours.

[0102] 3) Dispersing graphene slurry specifically includes: take: graphene powder: 50 mg, placed in a 1000 ml beaker; take sulfonic acid, polyethylene glycol (PEG), sodium dodecyl sulfate (SDS), IGP and cetyltrimethylammonium bromide (CTAB) and other one or several: 1000 mg, also added to the 1000 ml beaker containing graphite powder; take pure water 1000 ml; add in three times, one side adds a glass rod stirring, the three are initially mixed evenly; finally the three mixed slurry into the cell crusher under certain power at room temperature for several hours.

[0103] 2, preparation of carbon paper mixed slurry

[0104] 1) The effective composition of carbon paper mixed slurry: CNT, CF, polytetrafluoroethylene (PTFE), graphene; the content of each part of the carbon paper mixed slurry: take 0.3 mg / ml CNT slurry: m1 g, take 3 mg / ml CF slurry: m2 g, take 0.05 mg / ml graphene slurry: m3 g, take 0.06 mg / ul PTFE: m4 g, the mass ratio of the four is: m1: m2: m3: m4 = 1: (1-10): (0.1-10): 1.5 between the mass ratio mixed to form the mixed slurry.

[0105] 2) The carbon paper mixed slurry is prepared and added to a beaker, which is placed in an ultrasonic machine, and dispersed at room temperature for several minutes at a certain power to prepare a uniform mixed slurry.

[0106] 3. Preparation of flexible three-dimensional porous carbon paper

[0107] 1) The uniform mixed slurry is added to a vacuum filtration device, and after standing for a while, the slurry is filtered and dried to directly form a flexible three-dimensional porous carbon paper sample.

[0108] 2) After vacuum drying, the flexible three-dimensional porous carbon paper sample is heat treated at a high temperature of 200-500°C to form a flexible three-dimensional porous carbon paper that can be used for high-performance PEMFC.

[0109] The flexible three-dimensional porous carbon paper prepared by the above method has the following morphological characteristics at different SEM scales in the same area. The specific details are that a-i are the porous structures of the surface morphology characteristics in the range of 100 μm-0.5 μm magnification. It can be seen from the pore structure characteristics that the carbon paper has the following characteristics:

[0110] 1. The carbon fibers have the function of building the overall macroporous framework in the entire carbon paper, and can act as the "macroporous skeleton" of the carbon paper. In the compression process of the carbon paper, it can maintain the three-dimensional porous structure of the carbon paper and reduce the occurrence of closed pores.

[0111] 2. The carbon nanotubes, mesoporous carbon, graphene and other nanomaterials are filled in the carbon fiber porous "skeleton", and a new mesoporous network is established. The carbon nanotubes, wrapped graphene and hydrophobic agents and other materials form a three-dimensional porous structure in the mesoporous system, which can ensure that the porosity of the carbon paper is maintained at a high level, which is conducive to the air permeability of the carbon paper.

[0112] 3. The addition of carbon nanotubes, graphene and other high-conductivity materials in the three-dimensional conductive network of carbon fibers can "build" more conductive "bridge" network channels, ensuring that the electron transmission is maintained at a high level, and the internal resistance of the carbon paper can be reduced.

[0113] 4. The addition of one or more hydrophobic agents such as polytetrafluoroethylene, fluorinated ethylene propylene copolymer, and polyvinylidene fluoride emulsion around the mesopores will mix with carbon fibers, carbon nanotubes, graphene and other materials after heat treatment, and together build a three-dimensional porous structure. This three-dimensional porous carbon paper forms a hydrophobic coating around the porous interior, allowing liquid in the porous network to quickly overflow from the interior, ensuring that the carbon paper film is always at a high porosity, thereby reducing the "waterlogging" of the fuel cell during high-current testing, which causes the performance of the fuel cell to rapidly decrease.

[0114] 5. One or more hydrophobic agents of carbon nanotubes, graphene, polytetrafluoroethylene, fluorinated ethylene propylene copolymer and polyvinylidene fluoride emulsion, and carbon fibers are wound inside to form a three-dimensional porous structure network carbon paper, which can have high bending mechanical strength and increase the flexibility of the carbon paper.

[0115] The carbon paper and commercial carbon paper were made into MEA, and the polarization curve and battery power density curve were tested under the same battery test conditions. The test conditions were room temperature, certain back pressure, RH% = 100% MEA test results. From the overall MEA polarization curve analysis, the MEA made of the carbon paper has obvious advantages in ohmic polarization, and the limiting current can reach 1800 mA / cm 2 The peak power can reach 700 mW / cm 2 .

[0116] As can be seen from the above embodiments, the composite carbon paper is prepared by mixing several materials such as carbon fibers, carbon nanotubes, graphene, mesoporous carbon, graphitized carbon black, polytetrafluoroethylene and fluorinated ethylene propylene copolymer. The carbon paper can be applied to fuel cells, has three-dimensional porous structure, three-dimensional conductive channel network and high battery performance, etc. The flexible three-dimensional porous carbon paper can solve the practical application problems of the existing commercial carbon paper, such as large and uneven surface macropores, easy to break when bending, complicated process, high temperature graphitization, high energy consumption, etc.

[0117] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0118] It should be understood that the application is not limited to the embodiments described above, and various modifications and changes can be made without departing from the scope thereof. The scope of the application is limited only by the appended claims.

Claims

1. A flexible three-dimensional porous carbon paper, characterized by, The carbon nanotube slurry m1 g, the carbon fiber slurry m2 g, the graphene slurry m3 g and the polytetrafluoroethylene slurry m4 g, wherein the mass ratio of the carbon nanotube slurry, the carbon fiber slurry, the graphene slurry and the polytetrafluoroethylene slurry is m1:m2:m3:m4=1:(1-10):(0.1-10):1.5; the concentration of the carbon nanotube slurry is 0.1 mg / ml, the concentration of the carbon fiber slurry is 1 mg / ml, the concentration of the graphene slurry is 0.05 mg / ml, and the concentration of the polytetrafluoroethylene slurry is 0.06 mg / ul.

2. A preparation method of the flexible three-dimensional porous carbon paper according to claim 1, comprising the following steps: dispersing the carbon nanotube slurry, the carbon fiber slurry, the graphene slurry and the polytetrafluoroethylene slurry; mixing the carbon nanotube slurry, the carbon fiber slurry, the graphene slurry and the polytetrafluoroethylene slurry according to the mass ratio of 1:(1-10):(0.1-10):1.5 to form a carbon paper mixed slurry; adding the carbon paper mixed slurry into a vacuum filtration device, and performing suction filtration after standing to form a flexible three-dimensional porous carbon paper sample; vacuum drying the flexible three-dimensional porous carbon paper sample, and performing high-temperature heat treatment to form the flexible three-dimensional porous carbon paper.

3. The production method according to claim 2, wherein The dispersing of the carbon nanotube slurry comprises: weighing the carbon nanotube powder and placing it in a beaker; weighing one or more of sulfonic acid, polyethylene glycol (PEG), sodium dodecyl sulfate (SDS), Igepal CO-880 (IGP) and cetyltrimethylammonium bromide (CTAB) and placing them in the beaker; adding pure water into the beaker and mixing uniformly, and then adding into a cell crusher for dispersion at 10°C for 30-90 min.

4. The production method according to claim 2, wherein The dispersing of the carbon fiber slurry comprises: weighing the carbon fiber powder and placing it in a beaker; measuring pure water and adding it into the beaker; measuring one or more of methanol, ethanol, propanol, isopropanol, ethylene glycol, glycerol and cyclohexanol and adding them into the beaker; measuring acetone and adding it into the beaker to mix uniformly, and then adding into an ultrasonic machine for dispersion at room temperature for 2-20 min.

5. The production method according to claim 2, wherein The dispersing of the graphene slurry comprises: weighing the graphene powder and placing it in a beaker; weighing one or more of sulfonic acid, polyethylene glycol (PEG), sodium dodecyl sulfate (SDS), Igepal CO-880 (IGP) and cetyltrimethylammonium bromide (CTAB) and adding them into the beaker; adding pure water into the beaker and mixing uniformly, and then adding into a cell crusher for dispersion at room temperature for a certain time.

6. A flexible three-dimensional porous carbon paper, characterized by, obtained by the preparation method according to any one of claims 2-5.

7. A fuel cell characterized by comprising: comprising the flexible three-dimensional porous carbon paper according to claim 6.