Wide-temperature-range gas diffusion layer and preparation method and application thereof

Abstract

The invention discloses a wide-temperature-range gas diffusion layer and a preparation method and application thereof. The wide-temperature-range gas diffusion layer comprises a microporous layer and a carbon fiber substrate layer arranged on the surface of the microporous layer; the microporous layer comprises a labyrinth network structure formed by graphene, a single-walled carbon nanotube, a multi-walled carbon nanotube and a water repellent agent; the carbon fiber substrate layer comprises carbon fibers, single-walled carbon nanotubes, multi-walled carbon nanotubes and a water repellent agent. The gas diffusion layer material which is adjustable in porosity, has a certain water retention capacity and is suitable for the air-cooled PEMFC is successfully prepared by using graphene, carbon nanotubes and carbon fibers as raw materials through vacuum filtration assistance and heat treatment methods, the transmission diversity of liquid water in the gas diffusion layer can be effectively improved, and the gas diffusion layer material has a good application prospect. And the transmission distance is prolonged, the performance of the fuel cell under low humidity is improved, the mass transfer capability is improved, and the fuel cell has a relatively wide working temperature range.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel cells and relates to a wide temperature range gas diffusion layer, and more specifically, to a wide temperature range gas diffusion layer suitable for proton exchange membrane fuel cells and a preparation method and application thereof. Background Art

[0002] Proton exchange membrane fuel cell (PEMFC) is an energy conversion device that can convert chemical energy into electrical energy, and has great application prospects in the field of energy supply. According to the different cooling media, it can be divided into water-cooled PEMFC and air-cooled PEMFC. Compared with the structure of water-cooled PEMFC, the cathode of air-cooled PEMFC is exposed and directly in contact with the external environment. Its working mode is to introduce a certain amount of hydrogen on the anode side, and introduce excess air on the cathode side to react and dissipate heat at the same time, and use the water generated by the reaction to perform a self-humidifying chemical reaction process on the internal environment. Air-cooled PEMFC can be used in fields such as drone transportation and portable power supply due to its high energy conversion efficiency and simple structure.

[0003] The gas diffusion layer (GDL) is an important component of PEMFC. It supports the proton exchange membrane and the catalyst layer inside the battery, and provides a channel for electron conduction and gas-liquid transport. The gas diffusion layer material of traditional PEMFC has high conductivity, hydrophobicity, porosity and suitable pore size gradient, so as to remove the water produced by the reaction from the battery in time to avoid concentration polarization. The general GDL material is not suitable for air-cooled PEMFC because of its large pore size, which causes the liquid water to be discharged too quickly. Therefore, the gas diffusion layer material of air-cooled PEMFC needs a higher water retention capacity to slow down the rate of water loss, thereby maintaining the wettability of the proton exchange membrane and improving the performance of the battery.

[0004] CN110190295A discloses a method for preparing a gas diffusion layer of a low-pressure and low-humidity fuel cell, using a gas diffusion layer material obtained by compounding three different functional layers, the three functional layers are a conductive porous substrate layer, a hydrophobic low-humidity adaptation layer, and a microporous low-pressure adaptation layer. Carbon powder, methyl cellulose, and epoxy resin are mixed into a slurry and coated on a carbon fiber substrate and then dried to obtain a conductive porous substrate layer. The substrate layer is then immersed in a polytetrafluoroethylene solution, and a composite substrate layer is obtained after sintering treatment. The carbon powder solution is then sprayed onto the surface of the composite substrate layer, and carbonized in a nitrogen atmosphere to obtain a diffusion layer material with three functional layers. However, this method is cumbersome and costly, and is not suitable for mass production.

[0005] CN110797540A discloses a method for preparing a gas diffusion layer, wherein carbon black, carbon nanotubes, and isopropanol are prepared into a slurry, the slurry is evenly distributed on a support material by screen printing, and then a Nafion aqueous dispersion is sprayed on the surface of the support material coated with the slurry to obtain a gas diffusion layer material suitable for high temperature and low humidity conditions. However, due to the use of carbon nanotubes as fillers, the interior of the diffusion layer material is relatively dense, which has a certain effect on mass transfer; in addition, the use of Nafion aqueous dispersion as a hydrophilic agent will also poison the precious metal catalyst in contact with it.

[0006] In summary, the current commercial production process of gas diffusion layer materials is cumbersome and costly, and the gas diffusion layer substrate needs to be graphitized at high temperature, which places certain demands on equipment. In addition, the internal pore structure and pore size cannot be effectively regulated during the preparation of the commercial diffusion layer, so it cannot meet the requirements for water retention in air-cooled PEMFCs. Summary of the invention

[0007] The main purpose of the present invention is to provide a wide temperature range gas diffusion layer suitable for proton exchange membrane fuel cells and a preparation method thereof, so as to overcome the deficiencies in the prior art.

[0008] Another object of the present invention is to provide an application of the wide temperature range gas diffusion layer.

[0009] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes: An embodiment of the present invention provides a wide temperature range gas diffusion layer, comprising a microporous layer and a carbon fiber base layer arranged on the surface of the microporous layer; the microporous layer comprises a labyrinth network structure composed of graphene, single-walled carbon nanotubes, multi-walled carbon nanotubes and a hydrophobic agent, wherein graphene serves as a main body for constructing the labyrinth network structure and single-walled carbon nanotubes serve as a cross-linking agent; the carbon fiber base layer comprises carbon fibers, single-walled carbon nanotubes, multi-walled carbon nanotubes and a hydrophobic agent.

[0010] An embodiment of the present invention provides a method for preparing a wide temperature range gas diffusion layer, which comprises: providing a microporous layer slurry comprising graphene, single-walled carbon nanotubes, multi-walled carbon nanotubes, and a hydrophobic agent; Providing a carbon fiber base layer slurry comprising carbon fibers, single-walled carbon nanotubes, multi-walled carbon nanotubes, and a hydrophobic agent; filtering the microporous layer slurry on a base membrane to obtain a microporous layer; filtering the carbon fiber base layer slurry on the microporous layer to obtain a gas diffusion layer precursor; The gas diffusion layer precursor is calcined at high temperature to obtain the wide temperature range gas diffusion layer.

[0011] The embodiment of the present invention also provides the application of the wide temperature range gas diffusion layer in a proton exchange membrane fuel cell.

[0012] Correspondingly, an embodiment of the present invention further provides a proton exchange membrane fuel cell, which includes the aforementioned wide temperature range gas diffusion layer.

[0013] Compared with the prior art, the beneficial effects of the present invention include: The present invention uses graphene, carbon nanotubes, and carbon fibers as raw materials through vacuum filtration assistance and heat treatment, and successfully prepares a gas diffusion layer material with adjustable porosity, certain water retention capacity, and suitable for air-cooled PEMFC. The internal maze network structure is constructed by two-dimensional graphene sheets with a layered structure, and the structure most suitable for water transmission is obtained by optimizing the number of layers and particle size of the graphene sheets. The diversity of liquid water transmission inside the gas diffusion layer can be effectively improved, the transmission distance can be extended, the performance of the fuel cell under low humidity can be improved, and the mass transfer capacity can be improved. Compared with traditional gas diffusion layer materials, the use of gas diffusion layer materials with a maze network structure increases the peak power density by 1.9 times. In addition, the gas diffusion layer material has a relatively wide operating temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 This is a flow chart for preparing a wide temperature range gas diffusion layer material in a typical embodiment of the present invention; Figure 2a is a cross-sectional SEM image of a wide temperature range gas diffusion layer having a labyrinth network structure prepared in Example 1 of the present invention; Figure 2b is a cross-sectional SEM image of a commercial diffusion layer; Figure 3a is a comparison diagram of polarization curves of a commercial diffusion layer material and a wide temperature range gas diffusion layer material having a labyrinth network structure prepared in Example 1 of the present invention; Figure 3b It is an electrochemical AC impedance spectrum test graph of a commercial diffusion layer material and a wide temperature range gas diffusion layer material with a maze network structure prepared in Example 1 of the present invention; Figure 4a This is the polarization curve of the commercial diffusion layer at 20-80°C; Figure 4bThis is a polarization curve diagram of a wide temperature range gas diffusion layer having a maze network structure prepared in Example 1 of the present invention under the condition of 20-80°C; Figure 5a is a polarization curve diagram corresponding to the gas diffusion layer containing microporous layers with different graphene loadings in Examples 1-5 of the present invention, Figure 5b is the corresponding peak power density curve; Figure 6 is a polarization curve diagram of the gas diffusion layer obtained in Comparative Example 1-3; Figure 7 is a polarization curve diagram of the gas diffusion layer with different ratios of single-walled carbon nanotubes and multi-walled carbon nanotubes in Comparative Example 4; Figure 8 It is the polarization curve diagram of the gas diffusion layer obtained by heat treatment and without heat treatment in Comparative Example 5. DETAILED DESCRIPTION

[0016] In order to make the gas diffusion layer material of air-cooled PEMFC have high conductivity, high water retention and not affect the mass transfer capacity of the fuel cell, the inventor of this case proposed this technical solution after long-term research and a large number of experiments to prepare a new type of gas diffusion layer material, which improves the battery performance while ensuring that the method is simple, the structure is stable and easy to industrialize.

[0017] The technical solution, its implementation process and principle will be further explained as follows.

[0018] As one aspect of the technical solution of the present invention, a wide temperature range gas diffusion layer involved therein includes a microporous layer and a carbon fiber base layer arranged on the surface of the microporous layer; the microporous layer includes a maze network structure composed of graphene, single-walled carbon nanotubes, multi-walled carbon nanotubes and a hydrophobic agent, and the carbon fiber base layer includes carbon fibers, single-walled carbon nanotubes, multi-walled carbon nanotubes and a hydrophobic agent.

[0019] In the microporous layer, graphene is used as the main body to construct the maze network structure, single-walled carbon nanotubes are used as cross-linking agents to connect the components and provide a certain mechanical strength; multi-walled carbon nanotubes are used to adjust the porosity of the gas diffusion layer material to facilitate the timely discharge of excess liquid water.

[0020] In some specific embodiments, the hydrophobic agent in the gas diffusion layer can be any one or a combination of two or more of polytetrafluoroethylene, fluorinated ethylene propylene, polyvinylidene fluoride, silicone resin, silicone oil, etc., but is not limited thereto.

[0021] In some specific embodiments, the graphene includes a two-dimensional graphene sheet with a layered structure. Further, the size of the two-dimensional graphene sheet ranges from 1 to 20 μm, the thickness ranges from 10 to 100 nm, and the number of layers ranges from 1 to 3. The present invention uses a two-dimensional graphene sheet with a layered structure to construct an internal maze network structure, and obtains a structure most suitable for water transmission by optimizing the number of layers and particle size of the graphene sheet.

[0022] In some specific embodiments, the single-walled carbon nanotube has a diameter ranging from 1 to 5 nm and a length ranging from 1 to 30 μm.

[0023] In some specific embodiments, the aspect ratio of the single-walled carbon nanotube is in the range of 10 2 ~10 6 .

[0024] In some specific embodiments, the multi-walled carbon nanotubes have a diameter ranging from 5 to 15 nm and a length ranging from 0.5 to 2 μm.

[0025] In some specific embodiments, the aspect ratio of the multi-walled carbon nanotubes is 50-4000.

[0026] In some specific embodiments, the mass ratio of graphene, single-walled carbon nanotubes, multi-walled carbon nanotubes and hydrophobic agent in the microporous layer is 0.5-2.5: 0.1-0.6: 0.6-1.5: 0.5-1.0.

[0027] Furthermore, the mass ratio of the single-walled carbon nanotubes to the multi-walled carbon nanotubes is 1:2-1:5.

[0028] In order to control the internal porosity of the gas diffusion layer, two types of carbon nanotubes with different aspect ratios are used for regulation. Single-walled carbon nanotubes have a higher aspect ratio (usually 10 4 ), high strength, but easy to form a dense network structure inside the gas diffusion layer; multi-walled carbon nanotubes have a lower aspect ratio (usually 50~4000), lower strength, and easy to form a loose network structure. By adjusting the ratio of the two carbon nanotubes, the porosity inside the gas diffusion layer is optimized, and a gas diffusion layer material with water retention capacity is obtained.

[0029] In some specific embodiments, the thickness of the microporous layer is in the range of 80-100 μm.

[0030] Furthermore, the porosity of the microporous layer is in the range of 40-60%, and the diameter of the micropores contained therein is in the range of 0.1-1.5 μm.

[0031] In some specific embodiments, the mass ratio of carbon fiber, single-walled carbon nanotube, multi-walled carbon nanotube and hydrophobic agent in the carbon fiber base layer is 1-5: 0.2-1.0: 1.5-3.0: 0.8-2.0.

[0032] Furthermore, the carbon fiber has a diameter of 5-10 μm and a length of 0.5-5 mm.

[0033] In some specific embodiments, the thickness of the carbon fiber base layer is in the range of 100-120 μm, the porosity of the carbon fiber base layer is in the range of 60-85%, and the pore size range is between 1-100 μm.

[0034] Furthermore, the tensile strength of the carbon fiber base layer is 5-10 MPa.

[0035] In some specific embodiments, the thickness of the wide temperature range gas diffusion layer is between 180 and 220 μm.

[0036] Compared with the traditional gas diffusion layer material, the present invention uses the gas diffusion layer material with a labyrinth network structure to increase the peak power density by 1.9 times. In addition, the gas diffusion layer material has a relatively wide operating temperature, generally 20-80°C.

[0037] As another aspect of the technical solution of the present invention, it also relates to a method for preparing the aforementioned wide temperature range gas diffusion layer, which comprises: providing a microporous layer slurry comprising graphene, single-walled carbon nanotubes, multi-walled carbon nanotubes, and a hydrophobic agent; Providing a carbon fiber base layer slurry comprising carbon fibers, single-walled carbon nanotubes, multi-walled carbon nanotubes, and a hydrophobic agent; filtering the microporous layer slurry on a base membrane to obtain a microporous layer; filtering the carbon fiber base layer slurry on the microporous layer to obtain a gas diffusion layer precursor; The gas diffusion layer precursor is calcined at high temperature to obtain the wide temperature range gas diffusion layer.

[0038] In some embodiments, the preparation method includes: uniformly mixing a graphene dispersion, a single-walled carbon nanotube dispersion, a multi-walled carbon nanotube dispersion and a hydrophobic agent solution to form the microporous layer slurry.

[0039] In some more preferred embodiments, the preparation method specifically includes: mixing a graphene dispersion, a single-walled carbon nanotube dispersion, and a multi-walled carbon nanotube dispersion, and then adding a hydrophobic agent solution for ultrasonic treatment to obtain the microporous layer slurry.

[0040] The loading amount of graphene in the microporous layer slurry is 0.5-2.5 mg cm-2 The loading amount of single-walled carbon nanotubes is 0.1~0.6 mg cm -2 The loading amount of multi-walled carbon nanotubes is 0.6~1.5 mg cm -2 The loading amount of hydrophobic agent is 0.5~1.0 mg cm -2 , the ultrasound time range is 5~10min.

[0041] Furthermore, the mass ratio of the single-walled carbon nanotubes to the multi-walled carbon nanotubes is 1:2-1:5.

[0042] In some embodiments, the preparation method includes: uniformly mixing a carbon fiber dispersion, a single-walled carbon nanotube dispersion, a multi-walled carbon nanotube dispersion and a hydrophobic agent solution to form the carbon fiber base layer slurry.

[0043] In some more preferred embodiments, the preparation method specifically includes: mixing a carbon fiber dispersion, a single-walled carbon nanotube dispersion, and a multi-walled carbon nanotube dispersion, adding a hydrophobic agent solution to obtain the carbon fiber base layer slurry, and ultrasonically treating it.

[0044] The carbon fiber loading in the carbon fiber base layer slurry is 1-5 mg cm -2 The loading amount of single-walled carbon nanotubes is 0.2~1.0 mg cm -2 The loading amount of multi-walled carbon nanotubes is 1.5~3.0mg cm -2 The loading amount of hydrophobic agent is 0.8~2.0 mg cm -2 , the ultrasound time range is 5~10min.

[0045] In some preferred embodiments, the method for preparing the graphene dispersion used above includes: mixing graphene with water, and then ultrasonically stirring to obtain a graphene dispersion (also referred to as "graphene slurry").

[0046] Furthermore, the concentration of the graphene dispersion is 0.5-10 mg mL -1 .

[0047] In some preferred embodiments, the method for preparing the single-walled carbon nanotube dispersion used above includes: uniformly mixing single-walled carbon nanotubes, water and a dispersant, and ultrasonicating to obtain a single-walled carbon nanotube dispersion (also referred to as "single-walled carbon nanotube slurry").

[0048] Furthermore, the concentration of the single-walled carbon nanotube dispersion is 0.5-2 mg mL -1 .

[0049] Furthermore, the mass ratio of the single-walled carbon nanotube to the dispersant is 1:1-1:5.

[0050] In some preferred embodiments, the method for preparing the multi-walled carbon nanotube dispersion liquid adopted above comprises: uniformly mixing the multi-walled carbon nanotubes, water and a dispersant, and ultrasonicating to obtain the multi-walled carbon nanotube dispersion liquid.

[0051] Furthermore, the concentration of the multi-walled carbon nanotube dispersion is 0.5-20 mg mL -1 .

[0052] Furthermore, the mass ratio of the multi-walled carbon nanotubes to the dispersant is 1:1-1:5.

[0053] Furthermore, the type of the dispersant includes but is not limited to any one or a combination of two or more of dodecylbenzenesulfonic acid (DBSA), sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), etc.

[0054] In some preferred embodiments, the method for preparing the carbon fiber dispersion liquid used above comprises: mixing the carbon fiber with water and ultrasonicating to obtain the carbon fiber dispersion liquid.

[0055] Furthermore, the concentration of the carbon fiber dispersion is 0.5-10 mg mL -1 .

[0056] In some embodiments, the preparation method comprises: applying the microporous layer slurry on a substrate membrane, and draining the water by a vacuum filtration-assisted method, thereby obtaining the microporous layer on the substrate membrane. The present invention constructs a labyrinth network structure inside the gas diffusion layer by a vacuum filtration method, which can effectively improve the diversity of liquid water transmission inside the gas diffusion layer, extend the transmission distance, improve the performance of the fuel cell under low humidity, and improve the mass transfer capacity.

[0057] Furthermore, the base membrane includes a polypropylene (PP) filter membrane, but is not limited thereto.

[0058] In some embodiments, the preparation method includes: slowly dripping the carbon fiber base layer slurry onto the microporous layer, and then performing vacuum filtration again to remove water to obtain a gas diffusion layer precursor. Since the microporous layer has a low porosity and a small pore size, and the carbon fiber has a certain rigidity, the carbon fiber base layer slurry will not penetrate into the microporous layer.

[0059] In some embodiments, the high temperature calcination temperature ranges from 340 to 380° C., and the high temperature calcination time ranges from 30 to 60 min.

[0060] Among them, as one of the more specific implementation schemes, Figure 1As shown, the method for preparing the wide temperature range gas diffusion layer material may include the following steps: (1) Graphene slurry, single-walled carbon nanotube dispersion and multi-walled carbon nanotube dispersion are mixed, and then polytetrafluoroethylene (PTFE) solution is added for ultrasonic treatment for 5 to 10 minutes.

[0061] (2) The carbon fiber slurry, the single-walled carbon nanotube dispersion, and the multi-walled carbon nanotube dispersion are mixed, and finally a polytetrafluoroethylene (PTFE) solution is added as a hydrophobic agent to obtain a carbon fiber base layer slurry. The obtained carbon fiber base layer slurry is ultrasonically treated for 5 to 10 minutes using a 500W ultrasonic cleaning machine.

[0062] (3) A polypropylene (PP) filter membrane with a pore size of 0.45 μm is placed on a filtration device. Next, a microporous layer slurry containing single-walled carbon nanotubes and multi-walled carbon nanotubes in different mass ratios is poured onto the PP filter membrane. The water is drained off on the filter membrane by a vacuum filtration-assisted method to obtain microporous layers with different porosities.

[0063] (4) The prepared carbon fiber base layer slurry is slowly dripped onto the microporous layers with different porosities, and then a second vacuum filtration is performed to remove the moisture to obtain a gas diffusion layer precursor. The diffusion layer precursor is placed in a muffle furnace and calcined at 340-380 °C for 30-60 min to evenly disperse the PTFE inside the diffusion layer. Finally, a gas diffusion layer material suitable for air-cooled PEMFC is obtained.

[0064] As another aspect of the technical solution of the present invention, it also relates to a wide temperature range gas diffusion layer prepared by the aforementioned method.

[0065] Correspondingly, another aspect of an embodiment of the present invention further provides a proton exchange membrane fuel cell, which includes the aforementioned wide temperature range gas diffusion layer.

[0066] In summary, the present invention successfully prepares a gas diffusion layer material with adjustable porosity, certain water retention capacity and suitable for air-cooled PEMFC by using graphene, carbon nanotubes and carbon fibers as raw materials through vacuum filtration assistance and heat treatment.

[0067] The present invention will be described in more detail below in conjunction with the embodiments and drawings, but the embodiments do not limit the present invention. All variations associated with or derived from the contents disclosed in the present invention are considered to be within the protection scope of the present invention.

[0068] The size of the two-dimensional graphene sheets used in the following examples ranges from 1 to 20 μm, the thickness ranges from 10 to 100 nm, and the number of layers ranges from 1 to 3. The diameter of the single-walled carbon nanotubes ranges from 1 to 5 nm, the length ranges from 1 to 30 μm, and the aspect ratio ranges from 10 to 10. 2 ~10 6 The diameter of multi-walled carbon nanotubes ranges from 5 to 15 nm, the length ranges from 0.5 to 2 μm, and the aspect ratio ranges from 50 to 4000. The diameter of carbon fibers ranges from 5 to 10 μm, and the length ranges from 0.5 to 5 mm.

[0069] Example 1 A method for preparing a wide temperature range gas diffusion layer suitable for a proton exchange membrane fuel cell comprises the following steps: 1. Dispersion of carbon materials: 1. Dispersion of graphene: Weigh 500 mg of graphene powder and measure 100 mL of deionized water. Disperse 500 mg of graphene powder in 100 mL of deionized water and clean it with a 500W ultrasonic cleaner for 20 min. Stir with a glass rod while ultrasonicating to obtain 5 mg mL -1 Graphene slurry; 2. Dispersion of single-walled carbon nanotubes: Weigh 2 g of single-walled carbon nanotubes and measure 100 mg mL -1 50 mL of dodecylbenzenesulfonic acid (DBS) solution was added, and 950 mL of deionized water was measured. The mass ratio of single-walled carbon nanotubes to dodecylbenzenesulfonic acid was 1:2. The single-walled carbon nanotubes, DBS and deionized water were mixed evenly, and ultrasonicated for 1 h using a cell crusher to obtain a black uniform dispersion with a concentration of 2 mg mL -1 , and the dispersion has no obvious precipitation even after being left for several weeks.

[0070] 3. Dispersion of multi-walled carbon nanotubes: Weigh 5 g of multi-walled carbon nanotubes and measure 100 mg mL -1 100 mL of dodecylbenzenesulfonic acid (DBS) solution was added, and 150 mL of deionized water was measured. The multi-walled carbon nanotubes, DBS solution and deionized water were mixed evenly, stirred with a glass rod for 20 min, and then cleaned with a 500 W ultrasonic cleaner for 30 min to obtain 20 mg mL -1 The multi-walled carbon nanotube dispersion was left for several weeks without any obvious precipitation.

[0071] 4. Dispersion of carbon fiber: Weigh 500 mg of 5 mm carbon fiber and measure 100 mL of deionized water. Disperse 500 mg of 5 mm carbon fiber in 500 mL of deionized water, first stir evenly with a glass rod, then clean with a 500 W ultrasonic cleaner for 20 min to obtain 5 mg mL -1of carbon fiber slurry.

[0072] 2. Preparation of gas diffusion layer: a. Preparation of microporous layer slurry: Mix the prepared graphene slurry, single-walled carbon nanotube slurry and multi-walled carbon nanotube slurry in a beaker, and then add polytetrafluoroethylene (PTFE) solution to mix, wherein the graphene loading is 0.5 mg cm -2 The loading amounts of single-walled carbon nanotubes, multi-walled carbon nanotubes, and polytetrafluoroethylene were 0.2, 0.6, and 0.6 mg cm, respectively. -2 After 5 minutes of ultrasonic treatment, a uniformly dispersed microporous layer slurry was obtained.

[0073] b. Preparation of carbon fiber base layer slurry: The prepared carbon fiber slurry, single-walled carbon nanotube slurry, and multi-walled carbon nanotube slurry were mixed in a beaker, and finally polytetrafluoroethylene (PTFE) solution was added as a hydrophobic agent. The loading amounts of carbon fiber, single-walled carbon nanotube, multi-walled carbon nanotube, and polytetrafluoroethylene were 1.5 mg cm -2 , 0.2 mg cm -2 , 2.1 mg cm -2 , 1 mg cm -2 The obtained carbon fiber base layer slurry was ultrasonically treated for 5 minutes using a 500W ultrasonic cleaning machine to obtain a uniformly dispersed carbon fiber base layer slurry.

[0074] c. Filtration: Place a polypropylene (PP) filter membrane with a pore size of 0.45μm on the filtration device, then pour the microporous layer slurry containing single-walled carbon nanotubes and multi-walled carbon nanotubes on the PP filter membrane, and use vacuum filtration to drain the water on the filter membrane to obtain a microporous layer. Slowly drip the prepared carbon fiber base layer slurry on the microporous layer. Since the microporous layer has a low porosity, a small pore size, and the carbon fiber has a certain rigidity, the carbon fiber base layer slurry will not penetrate into the microporous layer. Then perform a second vacuum filtration to remove moisture, obtain a gas diffusion layer precursor, and separate the membrane.

[0075] d. Heat treatment: The diffusion layer precursor is placed in a muffle furnace and calcined at 350°C for 30 minutes to evenly disperse the PTFE inside the diffusion layer, and finally a gas diffusion layer material suitable for air-cooled PEMFC is obtained.

[0076] The inventors of this case characterized the prepared gas diffusion layer material as follows: 1. Characterization of microstructure: Scanning electron microscopy (Quanta 250, FEG) was used to characterize the microstructure of the gas diffusion layer material.

[0077] 2. Battery performance: The prepared gas diffusion layer materials are placed on both sides of the anode and cathode of the battery fixture, and the carbon fiber base layer ( Figure 1 The middle red layer) is close to the graphite flow field plate, and the graphene microporous layer ( Figure 1 The side of the medium blue layer is close to the catalyst layer, and the anode and cathode are separated by a catalyst coated membrane (CCM) to prevent gas leakage. The battery is further encapsulated using a polytetrafluoroethylene high temperature resistant membrane as a sealing gasket, and the obtained fuel cell is subjected to performance testing. Linear voltammetry is performed using an electrochemical workstation at room temperature and pressure, and the linear scanning curve at a potential of 0V (relative to open circuit)-0.4V (relative to reference) is tested to obtain the power density curve.

[0078] 3. Temperature tolerance test: Various gas diffusion layer materials are assembled into a single cell according to the above method for testing. Temperature is controlled as the only variable, and the fuel cell is tested at 20-80°C while keeping other test conditions the same. The test method is linear sweep voltammetry, and the test potential is 0V (relative to open circuit) -0.4V (relative to reference).

[0079] 4. Electrochemical impedance spectroscopy test: The battery was tested for electrochemical impedance spectroscopy at a working voltage of 0.6 V. The frequency range was set to 10 kHz-0.1 Hz, and the amplitude of the AC signal was maintained at 5% of the DC.

[0080] Characterization and test results: Figure 2a This is a cross-sectional SEM image of a wide temperature range gas diffusion layer with a maze network structure prepared in this embodiment. Figure 2b This is a cross-sectional SEM image of a commercial diffusion layer.

[0081] Figure 3a It is a comparison diagram of polarization curves of commercial diffusion layer materials and the wide temperature range gas diffusion layer material with a maze network structure prepared in this embodiment. Figure 3b These are electrochemical impedance spectroscopy test graphs of a commercial diffusion layer material and a wide temperature range gas diffusion layer material with a maze network structure prepared in this embodiment.

[0082] Figure 4a This is the polarization curve of the commercial diffusion layer at 20-80℃. Figure 4b This is a polarization curve diagram of the wide temperature range gas diffusion layer with a maze network structure prepared in this embodiment under the condition of 20-80°C.

[0083] Example 2 A method for preparing a wide temperature range gas diffusion layer suitable for a proton exchange membrane fuel cell comprises the following steps: a. Preparation of microporous layer slurry: Mix the prepared graphene slurry, single-walled carbon nanotube slurry and multi-walled carbon nanotube slurry in a beaker, and then add polytetrafluoroethylene (PTFE) solution to mix, wherein the loading amount of graphene is 1.0 mg / cm -2 The loading amounts of single-walled carbon nanotubes, multi-walled carbon nanotubes, and polytetrafluoroethylene were 0.2, 0.6, and 0.6 mg cm, respectively. -2 After 10 minutes of ultrasonic treatment, a uniformly dispersed microporous layer slurry was obtained.

[0084] b. Preparation of carbon fiber base layer slurry: The prepared carbon fiber slurry, single-walled carbon nanotube slurry, and multi-walled carbon nanotube slurry were mixed in a beaker, and finally polytetrafluoroethylene (PTFE) solution was added as a hydrophobic agent. The loading amounts of carbon fiber, single-walled carbon nanotube, multi-walled carbon nanotube, and polytetrafluoroethylene were 1.5 mg cm -2 , 0.2 mg cm -2 , 2.1 mg cm -2 , 1 mg cm -2 The obtained carbon fiber base layer slurry was ultrasonically treated for 10 minutes using a 500W ultrasonic cleaning machine to obtain a uniformly dispersed carbon fiber base layer slurry.

[0085] c. Filtration: Place a polypropylene (PP) filter membrane with a pore size of 0.45μm on the filtration device, then pour the microporous layer slurry containing single-walled carbon nanotubes and multi-walled carbon nanotubes on the PP filter membrane, and use vacuum filtration to drain the water on the filter membrane to obtain a microporous layer. Slowly drip the prepared carbon fiber base layer slurry on the microporous layer. Since the microporous layer has a low porosity, a small pore size, and the carbon fiber has a certain rigidity, the carbon fiber base layer slurry will not penetrate into the microporous layer. Then perform a second vacuum filtration to remove moisture, obtain a gas diffusion layer precursor, and separate the membrane.

[0086] d. Heat treatment: The diffusion layer precursor is placed in a muffle furnace and calcined at 350°C for 30 minutes to evenly disperse the PTFE inside the diffusion layer, and finally a gas diffusion layer material suitable for air-cooled PEMFC is obtained.

[0087] Example 3 A method for preparing a wide temperature range gas diffusion layer suitable for a proton exchange membrane fuel cell comprises the following steps: a. Preparation of microporous layer slurry: Mix the prepared graphene slurry, single-walled carbon nanotube slurry and multi-walled carbon nanotube slurry in a beaker, and then add polytetrafluoroethylene (PTFE) solution to mix, wherein the loading amount of graphene is 1.5 mgcm -2The loading amounts of single-walled carbon nanotubes, multi-walled carbon nanotubes, and polytetrafluoroethylene were 0.2, 0.6, and 0.6 mg cm, respectively. -2 After 10 minutes of ultrasonic treatment, a uniformly dispersed microporous layer slurry was obtained.

[0088] b. Preparation of carbon fiber base layer slurry: The prepared carbon fiber slurry, single-walled carbon nanotube slurry, and multi-walled carbon nanotube slurry were mixed in a beaker, and finally polytetrafluoroethylene (PTFE) solution was added as a hydrophobic agent. The loading amounts of carbon fiber, single-walled carbon nanotube, multi-walled carbon nanotube, and polytetrafluoroethylene were 1.5 mg cm -2 , 0.2 mg cm -2 , 2.1 mg cm -2 , 1 mg cm -2 The obtained carbon fiber base layer slurry was ultrasonically treated for 10 minutes using a 500W ultrasonic cleaning machine to obtain a uniformly dispersed carbon fiber base layer slurry.

[0089] c. Filtration: Place a polypropylene (PP) filter membrane with a pore size of 0.45μm on the filtration device, then pour the microporous layer slurry containing single-walled carbon nanotubes and multi-walled carbon nanotubes on the PP filter membrane, and use vacuum filtration to drain the water on the filter membrane to obtain a microporous layer. Slowly drip the prepared carbon fiber base layer slurry on the microporous layer. Since the microporous layer has a low porosity, a small pore size, and the carbon fiber has a certain rigidity, the carbon fiber base layer slurry will not penetrate into the microporous layer. Then perform a second vacuum filtration to remove moisture, obtain a gas diffusion layer precursor, and separate the membrane.

[0090] d. Heat treatment: The diffusion layer precursor is placed in a muffle furnace and calcined at 350°C for 30 minutes to evenly disperse the PTFE inside the diffusion layer, and finally a gas diffusion layer material suitable for air-cooled PEMFC is obtained.

[0091] Example 4 A method for preparing a wide temperature range gas diffusion layer suitable for a proton exchange membrane fuel cell comprises the following steps: a. Preparation of microporous layer slurry: Mix the prepared graphene slurry, single-walled carbon nanotube slurry and multi-walled carbon nanotube slurry into a beaker, and then add polytetrafluoroethylene (PTFE) solution to mix, wherein the loading amount of graphene is 2.0 mgcm -2 The loading amounts of single-walled carbon nanotubes, multi-walled carbon nanotubes, and polytetrafluoroethylene were 0.2, 0.6, and 0.6 mg cm, respectively. -2 After 10 minutes of ultrasonic treatment, a uniformly dispersed microporous layer slurry was obtained.

[0092] b. Preparation of carbon fiber base layer slurry: The prepared carbon fiber slurry, single-walled carbon nanotube slurry, and multi-walled carbon nanotube slurry were mixed in a beaker, and finally polytetrafluoroethylene (PTFE) solution was added as a hydrophobic agent. The loading amounts of carbon fiber, single-walled carbon nanotube, multi-walled carbon nanotube, and polytetrafluoroethylene were 1.5 mg cm -2 , 0.2 mg cm -2 , 2.1 mg cm -2 , 1 mg cm -2 The obtained carbon fiber base layer slurry was ultrasonically treated for 10 minutes using a 500W ultrasonic cleaning machine to obtain a uniformly dispersed carbon fiber base layer slurry.

[0093] c. Filtration: Place a polypropylene (PP) filter membrane with a pore size of 0.45μm on the filtration device, then pour the microporous layer slurry containing single-walled carbon nanotubes and multi-walled carbon nanotubes on the PP filter membrane, and use vacuum filtration to drain the water on the filter membrane to obtain a microporous layer. Slowly drip the prepared carbon fiber base layer slurry on the microporous layer. Since the microporous layer has a low porosity, a small pore size, and the carbon fiber has a certain rigidity, the carbon fiber base layer slurry will not penetrate into the microporous layer. Then perform a second vacuum filtration to remove moisture, obtain a gas diffusion layer precursor, and separate the membrane.

[0094] d. Heat treatment: The diffusion layer precursor is placed in a muffle furnace and calcined at 350°C for 30 minutes to evenly disperse the PTFE inside the diffusion layer, and finally a gas diffusion layer material suitable for air-cooled PEMFC is obtained.

[0095] Example 5 A method for preparing a wide temperature range gas diffusion layer suitable for a proton exchange membrane fuel cell comprises the following steps: a. Preparation of microporous layer slurry: Mix the prepared graphene slurry, single-walled carbon nanotube slurry and multi-walled carbon nanotube slurry in a beaker, and then add polytetrafluoroethylene (PTFE) solution to mix, wherein the graphene loading is 2.5 mgcm -2 The loading amounts of single-walled carbon nanotubes, multi-walled carbon nanotubes, and polytetrafluoroethylene were 0.2, 0.6, and 0.6 mg cm, respectively. -2 After 10 minutes of ultrasonic treatment, a uniformly dispersed microporous layer slurry was obtained.

[0096] b. Preparation of carbon fiber base layer slurry: The prepared carbon fiber slurry, single-walled carbon nanotube slurry, and multi-walled carbon nanotube slurry were mixed in a beaker, and finally polytetrafluoroethylene (PTFE) solution was added as a hydrophobic agent. The loading amounts of carbon fiber, single-walled carbon nanotube, multi-walled carbon nanotube, and polytetrafluoroethylene were 1.5 mg cm -2 , 0.2 mg cm-2 , 2.1 mg cm -2 , 1 mg cm -2 The obtained carbon fiber base layer slurry was ultrasonically treated for 10 minutes using a 500W ultrasonic cleaning machine to obtain a uniformly dispersed carbon fiber base layer slurry.

[0097] c. Filtration: Place a polypropylene (PP) filter membrane with a pore size of 0.45μm on the filtration device, then pour the microporous layer slurry containing single-walled carbon nanotubes and multi-walled carbon nanotubes on the PP filter membrane, and use vacuum filtration to drain the water on the filter membrane to obtain a microporous layer. Slowly drip the prepared carbon fiber base layer slurry on the microporous layer. Since the microporous layer has a low porosity, a small pore size, and the carbon fiber has a certain rigidity, the carbon fiber base layer slurry will not penetrate into the microporous layer. Then perform a second vacuum filtration to remove moisture, obtain a gas diffusion layer precursor, and separate the membrane.

[0098] d. Heat treatment: The diffusion layer precursor is placed in a muffle furnace and calcined at 350°C for 30 minutes to evenly disperse the PTFE inside the diffusion layer, and finally a gas diffusion layer material suitable for air-cooled PEMFC is obtained.

[0099] Figure 5a is a polarization curve diagram corresponding to the gas diffusion layer containing microporous layers with different graphene loadings in Examples 1-5, Figure 5b is the corresponding peak power density curve.

[0100] Example 6 A method for preparing a wide temperature range gas diffusion layer suitable for a proton exchange membrane fuel cell comprises the following steps: 1. Dispersion of carbon materials: 1. Dispersion of graphene: Weigh 50 mg of graphene powder and measure 100 mL of deionized water. Disperse 50 mg of graphene powder in 100 mL of deionized water and clean it with a 500W ultrasonic cleaner for 20 min. Stir with a glass rod while ultrasonicating to obtain 0.5 mg mL -1 Graphene slurry; 2. Dispersion of single-walled carbon nanotubes: Weigh single-walled carbon nanotubes, dodecylbenzenesulfonic acid (DBS) solution, and deionized water. The mass ratio of single-walled carbon nanotubes to dodecylbenzenesulfonic acid is 1:1. Mix single-walled carbon nanotubes, DBS, and deionized water evenly, and use a cell crusher to sonicate for 1 h to obtain a black uniform dispersion with a concentration of 0.5 mg mL -1 , and the dispersion has no obvious precipitation even after being left for several weeks.

[0101] 3. Dispersion of multi-walled carbon nanotubes: Weigh multi-walled carbon nanotubes, 100 mL of dodecylbenzenesulfonic acid (DBS) solution, and deionized water. The mass ratio of multi-walled carbon nanotubes to dispersant is 1:1. Mix the multi-walled carbon nanotubes, DBS solution, and deionized water evenly, stir with a glass rod for 20 min, and then clean with a 500 W ultrasonic cleaner for 30 min to obtain 10 mg mL -1 The multi-walled carbon nanotube dispersion was left for several weeks without any obvious precipitation.

[0102] 4. Dispersion of carbon fiber: Weigh 500 mg of 5 mm carbon fiber and measure 50 mL of deionized water. Disperse 500 mg of 5 mm carbon fiber in 50 mL of deionized water, first stir evenly with a glass rod, then clean with a 500 W ultrasonic cleaner for 20 min to obtain 10 mg mL -1 of carbon fiber slurry.

[0103] 2. Preparation of gas diffusion layer: a. Preparation of microporous layer slurry: Mix the prepared graphene slurry, single-walled carbon nanotube slurry and multi-walled carbon nanotube slurry in a beaker, and then add fluorinated ethylene propylene solution to mix, wherein the loading amount of graphene is 0.5 mg cm -2 The loading amounts of single-walled carbon nanotubes, multi-walled carbon nanotubes, and fluorinated ethylene propylene were 0.1, 0.6, and 0.5 mg cm -2 After 10 minutes of ultrasonic treatment, a uniformly dispersed microporous layer slurry was obtained.

[0104] b. Preparation of carbon fiber base layer slurry: The prepared carbon fiber slurry, single-walled carbon nanotube slurry, and multi-walled carbon nanotube slurry were mixed in a beaker, and finally fluorinated ethylene propylene solution was added as a hydrophobic agent. The loading amounts of carbon fiber, single-walled carbon nanotube, multi-walled carbon nanotube, and fluorinated ethylene propylene were 1 mg cm -2 , 0.2 mg cm -2 , 1.5 mg cm -2 , 0.8 mg cm -2 The obtained carbon fiber base layer slurry was ultrasonically treated for 5 minutes using a 500W ultrasonic cleaning machine to obtain a uniformly dispersed carbon fiber base layer slurry.

[0105] c. Filtration: Place a polypropylene (PP) filter membrane with a pore size of 0.45μm on the filtration device, then pour the microporous layer slurry containing single-walled carbon nanotubes and multi-walled carbon nanotubes on the PP filter membrane, and use vacuum filtration to drain the water on the filter membrane to obtain a microporous layer. Slowly drip the prepared carbon fiber base layer slurry on the microporous layer. Since the microporous layer has a low porosity, a small pore size, and the carbon fiber has a certain rigidity, the carbon fiber base layer slurry will not penetrate into the microporous layer. Then perform a second vacuum filtration to remove moisture, obtain a gas diffusion layer precursor, and separate the membrane.

[0106] d. Heat treatment: The diffusion layer precursor is placed in a muffle furnace and calcined at 340°C for 60 minutes to evenly disperse the PTFE inside the diffusion layer, and finally a gas diffusion layer material suitable for air-cooled PEMFC is obtained.

[0107] Example 7 A method for preparing a wide temperature range gas diffusion layer suitable for a proton exchange membrane fuel cell comprises the following steps: 1. Dispersion of carbon materials: 1. Graphene dispersion: Weigh 1000 mg of graphene powder and measure 100 mL of deionized water. Disperse 1000 mg of graphene powder in 100 mL of deionized water and clean it with a 500W ultrasonic cleaner for 20 min. Stir with a glass rod while ultrasonicating to obtain 10 mg mL -1 Graphene slurry; 2. Dispersion of single-walled carbon nanotubes: Weigh single-walled carbon nanotubes, dodecylbenzenesulfonic acid (DBS) solution, and deionized water. The mass ratio of single-walled carbon nanotubes to dodecylbenzenesulfonic acid is 1:5. Mix single-walled carbon nanotubes, DBS, and deionized water evenly, and use a cell crusher to sonicate for 1 h to obtain a black uniform dispersion with a concentration of 1 mg mL -1 , and the dispersion has no obvious precipitation even after being left for several weeks.

[0108] 3. Dispersion of multi-walled carbon nanotubes: Weigh multi-walled carbon nanotubes, 100 mL of dodecylbenzenesulfonic acid (DBS) solution, and deionized water. The mass ratio of multi-walled carbon nanotubes to dispersant is 1:5. Mix the multi-walled carbon nanotubes, DBS solution, and deionized water evenly, stir with a glass rod for 20 min, and then clean with a 500 W ultrasonic cleaner for 30 min to obtain 0.5 mg mL -1 The multi-walled carbon nanotube dispersion was left for several weeks without any obvious precipitation.

[0109] 4. Dispersion of carbon fiber: Weigh 50 mg of 5 mm carbon fiber and measure 100 mL of deionized water. Disperse 50 mg of 5 mm carbon fiber in 100 mL of deionized water, first stir evenly with a glass rod, then clean with a 500 W ultrasonic cleaner for 20 min to obtain 0.5 mg mL -1 of carbon fiber slurry.

[0110] 2. Preparation of gas diffusion layer: a. Preparation of microporous layer slurry: Mix the prepared graphene slurry, single-walled carbon nanotube slurry and multi-walled carbon nanotube slurry in a beaker, and then add polyvinylidene fluoride solution to mix, wherein the loading amount of graphene is 2.0 mg cm -2 The loading amounts of single-walled carbon nanotubes, multi-walled carbon nanotubes, and polyvinylidene fluoride were 0.6, 1.5, and 1.0 mg cm, respectively. -2 After 10 minutes of ultrasonic treatment, a uniformly dispersed microporous layer slurry was obtained.

[0111] b. Preparation of carbon fiber base layer slurry: The prepared carbon fiber slurry, single-walled carbon nanotube slurry, and multi-walled carbon nanotube slurry were mixed in a beaker, and finally polyvinylidene fluoride solution was added as a hydrophobic agent. The loading amounts of carbon fiber, single-walled carbon nanotube, multi-walled carbon nanotube, and polyvinylidene fluoride were 5 mg cm -2 , 1.0 mg cm -2 , 3.0 mg cm -2 , 2.0 mg cm -2 The obtained carbon fiber base layer slurry was ultrasonically treated for 8 minutes using a 500W ultrasonic cleaning machine to obtain a uniformly dispersed carbon fiber base layer slurry.

[0112] c. Filtration: Place a polypropylene (PP) filter membrane with a pore size of 0.45μm on the filtration device, then pour the microporous layer slurry containing single-walled carbon nanotubes and multi-walled carbon nanotubes on the PP filter membrane, and use vacuum filtration to drain the water on the filter membrane to obtain a microporous layer. Slowly drip the prepared carbon fiber base layer slurry on the microporous layer. Since the microporous layer has a low porosity, a small pore size, and the carbon fiber has a certain rigidity, the carbon fiber base layer slurry will not penetrate into the microporous layer. Then perform a second vacuum filtration to remove moisture, obtain a gas diffusion layer precursor, and separate the membrane.

[0113] d. Heat treatment: The diffusion layer precursor is placed in a muffle furnace and calcined at 380°C for 30 minutes to evenly disperse the PTFE inside the diffusion layer, and finally a gas diffusion layer material suitable for air-cooled PEMFC is obtained.

[0114] Comparative Example 1 This comparative example is basically the same as Example 1, except that no single-walled carbon nanotube slurry is added to the microporous layer slurry.

[0115] Comparative Example 2 This comparative example is basically the same as Example 1, except that no multi-walled carbon nanotube slurry is added to the microporous layer slurry.

[0116] Comparative Example 3 This comparative example is basically the same as Example 1, except that no single-walled carbon nanotube slurry and multi-walled carbon nanotube slurry are added to the microporous layer slurry.

[0117] like Figure 6 As shown, compared with the combination of graphene, single-walled, multi-walled carbon nanotubes and polytetrafluoroethylene, the battery performance of control examples 1-3 is reduced in the absence of single-walled, multi-walled or both, which indirectly proves that each component is indispensable. This is because adding additional conductive materials can increase the intrinsic conductivity of the microporous layer and improve performance.

[0118] Comparative Example 4 This comparative example is basically the same as Example 1, except that the mass ratio of single-walled carbon nanotubes to multi-walled carbon nanotubes in the microporous layer slurry is 1:1.

[0119] The inventors of this case also conducted a series of experiments on the mass ratio of single-walled carbon nanotubes to multi-walled carbon nanotubes, and tested 1:2, 1:3, 1:4, and 1:5 respectively. The polarization curves of the gas diffusion layer obtained at different ratios are shown in Figure 2. Figure 7 shown.

[0120] Comparative Example 5 This comparative example is substantially the same as Example 1, except that no heat treatment was performed.

[0121] See also Figure 8 , are the polarization curves of heat-treated and non-heat-treated layers. The purpose of heat treatment is to evenly disperse polytetrafluoroethylene in the gas diffusion layer. The results are consistent with the experimental principle. The gas diffusion layer without heat treatment has a more serious concentration polarization phenomenon, while no obvious concentration polarization occurs after heat treatment.

[0122] In addition, the inventors of this case also conducted experiments with other raw materials and conditions listed in this specification in accordance with the aforementioned embodiments, and obtained relatively ideal results.

[0123] It should be understood that the above are only specific application examples of the present invention and do not constitute any limitation on the protection scope of the present invention. Any technical solution formed by equivalent transformation or equivalent replacement falls within the protection scope of the present invention.

Claims

1. A wide temperature range gas diffusion layer, characterized in that: It includes a microporous layer and a carbon fiber base layer arranged on the surface of the microporous layer; the microporous layer includes a labyrinth network structure composed of graphene, single-walled carbon nanotubes, multi-walled carbon nanotubes and a hydrophobic agent, wherein graphene serves as the main body for constructing the labyrinth network structure and the single-walled carbon nanotubes serve as a cross-linking agent; the carbon fiber base layer includes carbon fibers, single-walled carbon nanotubes, multi-walled carbon nanotubes and a hydrophobic agent.

2. The wide temperature range gas diffusion layer according to claim 1, characterized in that: The graphene includes a two-dimensional graphene sheet with a layered structure. Preferably, the two-dimensional graphene sheet has a size of 1-20 μm, a thickness of 10-100 nm, and a number of layers of 1-3; And / or, the single-walled carbon nanotube has a diameter of 1-5 nm and a length of 1-30 μm; And / or, the aspect ratio of the single-walled carbon nanotube is 10 2 ~10 6 ; And / or, the multi-walled carbon nanotubes have a diameter of 5 to 15 nm and a length of 0.5 to 2 μm; And / or, the aspect ratio of the multi-walled carbon nanotubes is 50-4000; And / or, the hydrophobic agent includes any one or a combination of two or more of polytetrafluoroethylene, fluorinated ethylene propylene, polyvinylidene fluoride, silicone resin, and silicone oil.

3. The wide temperature range gas diffusion layer according to claim 1, characterized in that: The mass ratio of graphene, single-walled carbon nanotubes, multi-walled carbon nanotubes and hydrophobic agent in the microporous layer is 0.5-2.5: 0.1-0.6: 0.6-1.5: 0.5-1.0; Preferably, the mass ratio of the single-walled carbon nanotubes to the multi-walled carbon nanotubes is 1:2 to 1:5; And / or, the mass ratio of carbon fiber, single-walled carbon nanotube, multi-walled carbon nanotube and hydrophobic agent in the carbon fiber base layer is 1-5: 0.2-1.0: 1.5-3.0: 0.8-2.0; And / or, the carbon fiber has a diameter of 5-10 μm and a length of 0.5-5 mm.

4. The wide temperature range gas diffusion layer according to claim 1, characterized in that: The thickness of the microporous layer is 80-100 μm; and / or the porosity of the microporous layer is 40-60%, and the pore size of the micropores contained therein is 0.1-1.5 μm; And / or, the thickness of the carbon fiber base layer is 100-120 μm, the porosity of the carbon fiber base layer is 60-85%, and the pore size contained is 1-100 μm; And / or, the tensile strength of the carbon fiber base layer is 5-10 MPa; And / or, the thickness of the wide temperature range gas diffusion layer is 180-220 μm; And / or, the operating temperature of the wide temperature range gas diffusion layer is 20-80°C.

5. The method for preparing a wide temperature range gas diffusion layer according to any one of claims 1 to 4, characterized in that: include: providing a microporous layer slurry comprising graphene, single-walled carbon nanotubes, multi-walled carbon nanotubes, and a hydrophobic agent; Providing a carbon fiber base layer slurry comprising carbon fibers, single-walled carbon nanotubes, multi-walled carbon nanotubes, and a hydrophobic agent; filtering the microporous layer slurry on a base membrane to obtain a microporous layer; filtering the carbon fiber base layer slurry on the microporous layer to obtain a gas diffusion layer precursor; The gas diffusion layer precursor is calcined at high temperature to obtain the wide temperature range gas diffusion layer.

6. The preparation method according to claim 5, characterized in that: include: The graphene dispersion, the single-walled carbon nanotube dispersion, the multi-walled carbon nanotube dispersion and the hydrophobic agent solution are uniformly mixed to form the microporous layer slurry; Preferably, the preparation method specifically comprises: mixing a graphene dispersion, a single-walled carbon nanotube dispersion, and a multi-walled carbon nanotube dispersion, and then adding a hydrophobic agent solution for ultrasonic treatment to obtain the microporous layer slurry; The loading amount of graphene in the microporous layer slurry is 0.5-2.5 mg cm -2 The loading amount of single-walled carbon nanotubes is 0.1~0.6 mg cm -2 The loading amount of multi-walled carbon nanotubes is 0.6~1.5 mg cm -2 The loading amount of hydrophobic agent is 0.5~1.0 mg cm -2 , ultrasound time is 5~10min; Preferably, the mass ratio of the single-walled carbon nanotubes to the multi-walled carbon nanotubes is 1:2 to 1:5; And / or, the preparation method comprises: uniformly mixing a carbon fiber dispersion, a single-walled carbon nanotube dispersion, a multi-walled carbon nanotube dispersion and a hydrophobic agent solution to form the carbon fiber base layer slurry; Preferably, the preparation method specifically comprises: mixing a carbon fiber dispersion, a single-walled carbon nanotube dispersion, and a multi-walled carbon nanotube dispersion, adding a hydrophobic agent solution to obtain the carbon fiber base layer slurry, and ultrasonically treating the mixture; The carbon fiber loading in the carbon fiber base layer slurry is 1-5 mg cm -2 The loading amount of single-walled carbon nanotubes is 0.2~1.0 mg cm -2 The loading amount of multi-walled carbon nanotubes is 1.5~3.0mg cm -2 , the loading amount of hydrophobic agent is 0.8~2.0mg cm -2 , the ultrasonic time is 5~10min.

7. The preparation method according to claim 6, characterized in that include: Graphene is mixed with water, and then ultrasonically stirred to obtain a graphene dispersion; preferably, the concentration of the graphene dispersion is 0.5-10 mg mL -1 ; And / or, the preparation method comprises: uniformly mixing single-walled carbon nanotubes, water and a dispersant, and ultrasonicating to obtain a single-walled carbon nanotube dispersion; preferably, the concentration of the single-walled carbon nanotube dispersion is 0.5-2 mg mL -1 ; Preferably, the mass ratio of the single-walled carbon nanotubes to the dispersant is 1:1 to 1:5; And / or, the preparation method comprises: uniformly mixing multi-walled carbon nanotubes, water and a dispersant, and ultrasonicating to obtain a multi-walled carbon nanotube dispersion; preferably, the concentration of the multi-walled carbon nanotube dispersion is 0.5-20 mg mL -1 ; Preferably, the mass ratio of the multi-walled carbon nanotubes to the dispersant is 1:1 to 1:5; Preferably, the dispersant includes any one or a combination of two or more of dodecylbenzenesulfonic acid, sodium dodecyl sulfate, hexadecyltrimethylammonium bromide, polyvinylpyrrolidone, and polyethylene glycol; And / or, the preparation method comprises: mixing carbon fiber with water and ultrasonicating to obtain a carbon fiber dispersion; preferably, the concentration of the carbon fiber dispersion is 0.5-10 mg mL -1 .

8. The preparation method according to claim 5, characterized in that: include: Applying the microporous layer slurry on the base membrane, and draining the water by vacuum filtration assisted method, thereby obtaining the microporous layer on the base membrane; Preferably, the base membrane comprises a polypropylene filter membrane; And / or, the preparation method comprises: slowly dripping the carbon fiber base layer slurry onto the microporous layer, and then performing vacuum filtration again to remove moisture to obtain a gas diffusion layer precursor; And / or, the high temperature calcination temperature is 340-380° C., and the high temperature calcination time is 30-60 min.

9. Use of the wide temperature range gas diffusion layer according to any one of claims 1 to 4 in a proton exchange membrane fuel cell.

10. A proton exchange membrane fuel cell, characterized in that: The invention comprises the wide temperature range gas diffusion layer according to any one of claims 1 to 4.

Images