Base material of gas diffusion layer and application of base material in polymer electrolyte membrane fuel cell

Abstract

The invention provides a matrix material of a gas diffusion layer and application of the matrix material in a polymer electrolyte membrane fuel cell, and the preparation of the matrix material comprises the following steps: S1, adding graphene oxide into normal hexane, adding nanofiber-shaped iron-nickel alloy powder and melamine, stirring, transferring the solution into a high-pressure reaction kettle, and carrying out a hydrothermal reaction, calcining in an inert gas atmosphere to obtain a product, stirring the product in a hydrochloric acid solution, filtering and washing to obtain an N / C-Ni material; s2, preparing raw paper from the chopped carbon fibers, the modified polyurethane and an adhesive through dry-process paper forming or wet-process paper forming; and S3, adding the N / C-coated Ni material into absolute ethyl alcohol to obtain a solution, dipping the raw paper in the step S2 into the solution, and carrying out vacuumizing treatment, hot pressing and carbonization to obtain a base material of the target gas diffusion layer. The base material of the gas diffusion layer has the characteristics of small thickness and stable structure, can reduce the flooding phenomenon of the fuel cell, improves the mass transfer capability, and has a good application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a matrix material for a gas diffusion layer and its application in polymer electrolyte membrane fuel cells. Background Art

[0002] The core component of a proton exchange membrane fuel cell (PEMFC) is the membrane electrode (MEA), which consists of a gas diffusion layer, a catalyst layer, and a proton exchange membrane. The gas diffusion layer (GDL), located between the catalyst layer and the bipolar plate, performs functions such as water vapor transport, electron conduction, and heat transfer. The GDL plays multiple roles in fuel cells, including supporting the catalyst layer, collecting current, conducting gas, and discharging water. It enables the redistribution of reactant gases and product water between the flow field and the catalyst layer, and is a key material influencing electrode performance. GDLs are generally required to have good electrical conductivity, hydrophobicity, air permeability, and mechanical strength.

[0003] Currently, fuel cell gas diffusion layers primarily use carbon paper as a substrate. This is achieved by combining carbon fibers, polymer fibers, and a binder to create a paper. This paper is then carbonized at 1600°C to create the carbon fiber paper. However, this paper suffers from issues such as thickness, brittleness, poor flexibility, and high energy consumption. The resulting gas diffusion layers are typically around 200μm thick. Existing methods for directly fabricating gas diffusion layers using graphene, carbon nanotubes, and carbon black have been proposed. While these methods can reduce the thickness of gas diffusion layers, their low tensile strength significantly limits their application.

[0004] In addition, the resistance of the gas diffusion layer is a characteristic parameter of its ability to transmit electrons. As the electrochemical reaction proceeds, the reaction product water will accumulate near the cathode catalytic layer. This water will not only diffuse through the proton exchange membrane to the anode, but more importantly, it will diffuse through the cathode diffusion layer to the cathode flow field. If this liquid water cannot be transferred quickly, it will cause water accumulation in the diffusion layer, which is called water flooding.

[0005] Therefore, it is necessary to develop a matrix material for the gas diffusion layer that has a thin thickness, stable structure, reduces fuel cell flooding, and improves mass transfer capacity. Summary of the Invention

[0006] In view of this, the present invention proposes a matrix material for a gas diffusion layer and its application in a polymer electrolyte membrane fuel cell.

[0007] The technical solution of the present invention is achieved as follows:

[0008] A method for preparing a base material of a gas diffusion layer comprises the following steps:

[0009] S1. Adding graphene oxide to n-hexane, adding nanofibrous iron-nickel alloy powder and melamine and stirring, transferring the solution to a high-pressure reactor for hydrothermal reaction, calcining under an inert gas atmosphere to obtain a product, stirring the product in a hydrochloric acid solution, filtering and washing, and obtaining a N / C@Ni material;

[0010] S2. preparing base paper by dry-laying or wet-laying the chopped carbon fibers, modified polyurethane, and a binder;

[0011] S3. Add the N / C@Ni material into anhydrous ethanol to obtain a solution, immerse the base paper of S2 in the solution, vacuum-treat, hot-press, and carbonize to obtain the base material of the target gas diffusion layer.

[0012] Furthermore, in step S1, the solid-liquid ratio of the graphene oxide to n-hexane is 1:15-20 g / mL; and the mass ratio of the graphene oxide, nanofibrous iron-nickel alloy powder, and melamine is 10:1.5-2.8:2-3.

[0013] Furthermore, in step S1, the temperature of the hydrothermal reaction is 140-180°C and the time is 12-24 hours; the calcination is carried out at 300-400°C for 20-30 minutes, and then the temperature is raised to 500-600°C and calcined for 2-4 hours.

[0014] Furthermore, in step S1, the solid-liquid ratio of the product to the hydrochloric acid solution is 1:15-25 g / mL; the concentration of the hydrochloric acid solution is 0.05-0.07 mol / L; and the stirring is performed at 100-200 rpm for 10-12 hours.

[0015] Furthermore, in step S2, the mass ratio of the chopped carbon fibers, the modified polyurethane, and the adhesive is 1:5-10:1-2.

[0016] Furthermore, the preparation method of the modified polyurethane is as follows: amino-terminated polydimethylsiloxane and hexamethylene diisocyanate are mixed and stirred to obtain a material, and the material is reacted with pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propylenediamine to obtain the modified polyurethane;

[0017] The mass ratio of the amino-terminated polydimethylsiloxane, hexamethylene diisocyanate, pentaerythritol, polycarbonate diol and N,N,N',N'-tetraethyl-1,3-propylene diamine is 1:1-2:0.5-0.8:0.3-0.5:0.01-0.03.

[0018] Furthermore, the adhesive is polyacrylonitrile and hydroxypropyl methylcellulose in a mass ratio of 1:1-3.

[0019] Furthermore, in step S3, the solid-liquid ratio of the N / C@Ni material to anhydrous ethanol is 1:20-30 g / mL; the loading amount of the N / C@Ni material on the base paper is 1-2 mg / cm 2 ; The thickness of the base material of the gas diffusion layer is 50-80μm.

[0020] A base material for a gas diffusion layer is prepared by any of the methods described above.

[0021] The invention discloses an application of a matrix material of a gas diffusion layer in a polymer electrolyte membrane fuel cell.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The modified polyurethane used in the preparation of the base paper of the present invention not only imparts toughness and elasticity, but also possesses thermal stability and low-temperature adaptability, maintaining good flexibility at low temperatures and preventing brittle cracking. Furthermore, it increases the tensile strength of the base paper. Furthermore, the modified polyurethane of the present invention enhances the hydrophobicity of the substrate, helping to prevent moisture accumulation.

[0024] 2. The N / C@Ni material of the present invention forms a porous structure by acid-etching nanofibrous iron-nickel alloy powder, increasing surface roughness and porosity. The porous nanofibrous nickel powder is then encapsulated in a carbon-nitrogen material. This not only increases strength, thermal conductivity, and electrical conductivity, but also enhances resistance to electrical corrosion and improves the stability of the matrix material. Impregnating the porous N / C@Ni material onto base paper creates a gradient porous structure, improving mass transfer and reducing fuel cell flooding. DETAILED DESCRIPTION

[0025] In order to better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention.

[0026] Unless otherwise specified, the experimental methods used in the examples of the present invention are all conventional methods.

[0027] Unless otherwise specified, the materials, reagents, etc. used in the examples of the present invention can be obtained from commercial sources.

[0028] Example 1

[0029] A method for preparing a base material of a gas diffusion layer comprises the following steps:

[0030] S1, according to the solid-liquid ratio of 1:15g / mL, graphene oxide was added to n-hexane, nanofibrous iron-nickel alloy powder and melamine were added and stirred, the mass ratio of graphene oxide, nanofibrous iron-nickel alloy powder and melamine was 10:1.5:2, the solution was moved to a high-pressure reactor, a hydrothermal reaction was carried out at 140°C for 12h, and calcined under an inert gas atmosphere, specifically: calcined at 300°C for 20min, then the temperature was raised to 500°C and calcined for 2h, and the furnace was cooled to obtain a product, according to the solid-liquid ratio of 1:15g / mL, the product was stirred at 100rpm for 10h in 0.05mol / L hydrochloric acid solution, filtered and washed to obtain N / C@Ni material;

[0031] S2. preparing base paper by dry-laying or wet-laying short carbon fibers, modified polyurethane, and a binder (polyacrylonitrile and hydroxypropyl methylcellulose in a mass ratio of 1:5:1);

[0032] The modified polyurethane is prepared by mixing and stirring amino-terminated polydimethylsiloxane and hexamethylene diisocyanate to obtain a material, and reacting the material with pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propylene diamine to obtain the modified polyurethane, wherein the mass ratio of amino-terminated polydimethylsiloxane, hexamethylene diisocyanate, pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propylene diamine is 1:1:0.5:0.3:0.01;

[0033] S3: Add N / C@Ni material to anhydrous ethanol at a solid-liquid ratio of 1:20 g / mL to obtain a solution. Immerse the base paper of S2 in the solution, vacuum it, mix it with phenolic resin, and hot-press and carbonize it to obtain the base material of the target gas diffusion layer with a thickness of 50 μm. The loading amount of N / C@Ni material on the base paper is 1 mg / cm 2 .

[0034] Example 2

[0035] A method for preparing a base material of a gas diffusion layer comprises the following steps:

[0036] S1, according to the solid-liquid ratio of 1:18g / mL, graphene oxide was added to n-hexane, nanofibrous iron-nickel alloy powder and melamine were added and stirred, the mass ratio of graphene oxide, nanofibrous iron-nickel alloy powder and melamine was 10:2:2.5, the solution was transferred to a high-pressure reactor, hydrothermally reacted at 160°C for 18h, and calcined under an inert gas atmosphere, specifically: calcined at 350°C for 25min, then the temperature was raised to 550°C and calcined for 3h, and cooled with the furnace to obtain a product, according to the solid-liquid ratio of 1:20g / mL, the product was stirred at 150rpm in 0.06mol / L hydrochloric acid solution for 11h, filtered and washed to obtain N / C@Ni material;

[0037] S2. preparing base paper by dry-laying or wet-laying short carbon fibers, modified polyurethane, and an adhesive in a mass ratio of 1:8:1.5;

[0038] The modified polyurethane is prepared by mixing and stirring amino-terminated polydimethylsiloxane and hexamethylene diisocyanate to obtain a material, and reacting the material with pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propylene diamine to obtain the modified polyurethane, wherein the mass ratio of amino-terminated polydimethylsiloxane, hexamethylene diisocyanate, pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propylene diamine is 1:1.5:0.6:0.4:0.02;

[0039] S3: Add N / C@Ni material to anhydrous ethanol at a solid-liquid ratio of 1:25 g / mL to obtain a solution. Immerse the base paper of S2 in the solution, vacuum it, mix it with phenolic resin, and hot-press and carbonize it to obtain the base material of the target gas diffusion layer with a thickness of 100 μm. The loading amount of N / C@Ni material on the base paper is 1.5 mg / cm 2 .

[0040] Example 3

[0041] A method for preparing a base material of a gas diffusion layer comprises the following steps:

[0042] S1, according to the solid-liquid ratio of 1:20g / mL, graphene oxide was added to n-hexane, nanofibrous iron-nickel alloy powder and melamine were added and stirred, the mass ratio of graphene oxide, nanofibrous iron-nickel alloy powder and melamine was 10:2.8:3, the solution was moved to a high-pressure reactor, a hydrothermal reaction was carried out at 180°C for 24h, and calcined under an inert gas atmosphere, specifically: calcined at 400°C for 30min, then the temperature was raised to 600°C and calcined for 4h, and cooled with the furnace to obtain a product, according to the solid-liquid ratio of 1:25g / mL, the product was stirred at 200rpm in 0.07mol / L hydrochloric acid solution for 12h, filtered and washed to obtain N / C@Ni material;

[0043] S2. preparing base paper by dry-laying or wet-laying short carbon fibers, modified polyurethane, and an adhesive in a mass ratio of 1:10:2;

[0044] The modified polyurethane is prepared by mixing and stirring amino-terminated polydimethylsiloxane and hexamethylene diisocyanate to obtain a material, and reacting the material with pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propylene diamine to obtain the modified polyurethane, wherein the mass ratio of amino-terminated polydimethylsiloxane, hexamethylene diisocyanate, pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propylene diamine is 1:2:0.8:0.5:0.03;

[0045] S3: Add N / C@Ni material to anhydrous ethanol at a solid-liquid ratio of 1:30 g / mL to obtain a solution. Immerse the base paper of S2 in the solution, vacuum it, mix it with phenolic resin, and hot-press and carbonize it to obtain the base material of the target gas diffusion layer with a thickness of 150 μm. The loading amount of N / C@Ni material on the base paper is 2 mg / cm 2 .

[0046] Comparative Example 1

[0047] The difference from Example 2 is that nanofibrous iron-nickel powder and carbon powder are mixed, and the rest are the same as Example 2.

[0048] That is, the preparation method of the base material of the gas diffusion layer of this comparative example comprises the following steps:

[0049] S1. Add nanofibrous iron-nickel alloy powder to 0.06 mol / L hydrochloric acid solution at a solid-to-liquid ratio of 1:20 g / mL, stir at 150 rpm, filter, wash, and dry to obtain nanofibrous nickel powder;

[0050] S2. preparing base paper by dry-laying or wet-laying short carbon fibers, modified polyurethane, and an adhesive in a mass ratio of 1:8:1.5;

[0051] The modified polyurethane is prepared by mixing and stirring amino-terminated polydimethylsiloxane and hexamethylene diisocyanate to obtain a material, and reacting the material with pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propylene diamine to obtain the modified polyurethane, wherein the mass ratio of amino-terminated polydimethylsiloxane, hexamethylene diisocyanate, pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propylene diamine is 1:1.5:0.6:0.4:0.02;

[0052] S3, according to the solid-liquid ratio of 1:25g / mL, nanofibrous nickel powder and carbon powder with a mass ratio of 2:10 were added to anhydrous ethanol to obtain a solution, the base paper of S2 was immersed in the solution, vacuumed, mixed with phenolic resin, hot pressed, and carbonized to obtain the base material of the target gas diffusion layer with a thickness of 100μm. The loading amount of nanofibrous nickel powder and carbon powder on the base paper was 1.5mg / cm 2 .

[0053] Comparative Example 2

[0054] The difference from Example 2 is that step S1 is missing, and the rest is consistent with Example 2.

[0055] That is, the preparation method of the base material of the gas diffusion layer of this comparative example comprises the following steps:

[0056] The base paper is prepared by dry or wet paper making of chopped carbon fibers, modified polyurethane and adhesive in a mass ratio of 1:8:1.5, and then mixed with phenolic resin, hot pressed and carbonized to obtain a base material of a gas diffusion layer with a thickness of 100 μm.

[0057] Among them, the preparation method of the modified polyurethane is: amino-terminated polydimethylsiloxane and hexamethylene diisocyanate are mixed and stirred to obtain a material, and the material is reacted with pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propylene diamine to obtain the modified polyurethane, wherein the mass ratio of amino-terminated polydimethylsiloxane, hexamethylene diisocyanate, pentaerythritol, polycarbonate diol and N,N,N',N'-tetraethyl-1,3-propylene diamine is 1:1.5:0.6:0.4:0.02.

[0058] Comparative Example 3

[0059] The difference from Example 2 is that modified polyurethane is missing in step S2, and the rest is consistent with Example 2.

[0060] That is, the preparation method of the base material of the gas diffusion layer of this comparative example comprises the following steps:

[0061] S1, according to the solid-liquid ratio of 1:18g / mL, graphene oxide was added to n-hexane, nanofibrous iron-nickel alloy powder and melamine were added and stirred, the mass ratio of graphene oxide, nanofibrous iron-nickel alloy powder and melamine was 10:2:2.5, the solution was transferred to a high-pressure reactor, hydrothermally reacted at 160°C for 18h, and calcined under an inert gas atmosphere, specifically: calcined at 350°C for 25min, then the temperature was raised to 550°C and calcined for 3h, and cooled with the furnace to obtain a product, according to the solid-liquid ratio of 1:20g / mL, the product was stirred at 150rpm in 0.06mol / L hydrochloric acid solution for 11h, filtered and washed to obtain N / C@Ni material;

[0062] S2. preparing base paper by dry-laying or wet-laying short carbon fibers and a binder in a mass ratio of 1:1.5;

[0063] S3: Add N / C@Ni material to anhydrous ethanol at a solid-liquid ratio of 1:25 g / mL to obtain a solution. Immerse the base paper of S2 in the solution, vacuum it, mix it with phenolic resin, and hot-press and carbonize it to obtain the base material of the target gas diffusion layer with a thickness of 100 μm. The loading amount of N / C@Ni material on the base paper is 1.5 mg / cm 2 .

[0064] Comparative Example 4

[0065] The method for preparing the base material of the gas diffusion layer of this comparative example comprises the following steps:

[0066] S1. Graphene oxide was added to n-hexane at a solid-liquid ratio of 1:18 g / mL, and nickel nitrate and melamine were added and stirred. The mass ratio of graphene oxide, nickel nitrate and melamine was 10:2:2.5. The solution was transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 160°C for 18 hours. The mixture was calcined under an inert gas atmosphere, specifically at 350°C for 25 minutes, then the temperature was raised to 550°C and calcined for 3 hours. The mixture was cooled in the furnace to obtain N / C@Ni material.

[0067] S2. preparing base paper by dry-laying or wet-laying short carbon fibers, modified polyurethane, and an adhesive in a mass ratio of 1:8:1.5;

[0068] The modified polyurethane is prepared by mixing and stirring amino-terminated polydimethylsiloxane and hexamethylene diisocyanate to obtain a material, and reacting the material with pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propylene diamine to obtain the modified polyurethane, wherein the mass ratio of amino-terminated polydimethylsiloxane, hexamethylene diisocyanate, pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propylene diamine is 1:1.5:0.6:0.4:0.02;

[0069] S3: Add N / C@Ni material to anhydrous ethanol at a solid-liquid ratio of 1:25 g / mL to obtain a solution. Immerse the base paper of S2 in the solution, vacuum it, mix it with phenolic resin, and hot-press and carbonize it to obtain the base material of the target gas diffusion layer with a thickness of 100 μm. The loading amount of N / C@Ni material on the base paper is 1.5 mg / cm 2 .

[0070] Test Case

[0071] The base materials prepared in Examples 1-3 and Comparative Examples 1-4 were cut into pieces of 5 cm×5 cm and subjected to performance tests.

[0072] Test indicators: 1. Use TQD-G1 air permeability tester to test the air permeability in accordance with GB / T20042 to evaluate the gas diffusion properties of the sample;

[0073] 2. Use ZY9987 digital micro-ohmmeter to test the resistivity at 0.6MPa to evaluate the conductivity of the sample;

[0074] 3. According to GB / T20042, use a universal testing machine to test the bending strength and tensile strength to evaluate the mechanical properties of the sample;

[0075] 4. The porosity of the experimental sample is calculated by mercury intrusion testing to evaluate the mass transfer capacity of the sample.

[0076] The test results are shown in Table 1.

[0077] Table 1

[0078]

[0079] As can be seen from Table 1, the base material of the gas diffusion layer prepared in the present invention exhibits good gas diffusivity, excellent electrical conductivity, superior mechanical properties, a high porosity enabling good mass transfer, and good hydrophobicity. Compared to Example 2, the various performance indicators of Comparative Examples 1-4 decreased to varying degrees.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a base material for a gas diffusion layer, characterized in that: The following steps are involved: S1. Adding graphene oxide to n-hexane, adding nanofibrous iron-nickel alloy powder and melamine and stirring, transferring the solution to a high-pressure reactor for hydrothermal reaction, calcining under an inert gas atmosphere to obtain a product, stirring the product in a hydrochloric acid solution, filtering and washing, and obtaining a N / C@Ni material; S2. preparing base paper by dry-laying or wet-laying the chopped carbon fibers, modified polyurethane, and a binder; S3. Add the N / C@Ni material into anhydrous ethanol to obtain a solution, immerse the base paper of S2 in the solution, vacuum-treat, hot-press, and carbonize to obtain the base material of the target gas diffusion layer.

2. The method for preparing the matrix material according to claim 1, wherein: In step S1, the solid-liquid ratio of the graphene oxide to n-hexane is 1:15-20 g / mL; and the mass ratio of the graphene oxide, nanofibrous iron-nickel alloy powder, and melamine is 10:1.5-2.8:2-3.

3. The method for preparing the matrix material according to claim 1, wherein: In step S1, the temperature of the hydrothermal reaction is 140-180° C., and the time is 12-24 hours; the calcination is carried out at 300-400° C. for 20-30 minutes, and then the temperature is raised to 500-600° C. and calcined for 2-4 hours.

4. The method for preparing the matrix material according to claim 1, wherein: In step S1, the solid-liquid ratio of the product to the hydrochloric acid solution is 1:15-25 g / mL; the concentration of the hydrochloric acid solution is 0.05-0.07 mol / L; and the stirring is performed at 100-200 rpm for 10-12 hours.

5. The method for preparing the base material according to claim 1, wherein: In step S2, the mass ratio of the chopped carbon fibers, the modified polyurethane, and the adhesive is 1:5-10:1-2.

6. The method for preparing the base material according to claim 4, wherein: The preparation method of the modified polyurethane comprises: mixing and stirring amino-terminated polydimethylsiloxane and hexamethylene diisocyanate to obtain a material, and reacting the material with pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propylenediamine to obtain the modified polyurethane; The mass ratio of the amino-terminated polydimethylsiloxane, hexamethylene diisocyanate, pentaerythritol, polycarbonate diol and N,N,N',N'-tetraethyl-1,3-propylene diamine is 1:1-2:0.5-0.8:0.3-0.5:0.01-0.

03.

7. The method for preparing a base material according to claim 4, wherein: The adhesive is polyacrylonitrile and hydroxypropyl methylcellulose in a mass ratio of 1:1-3.

8. The method for preparing a base material according to claim 1, wherein: In step S3, the solid-liquid ratio of the N / C@Ni material to anhydrous ethanol is 1:20-30 g / mL; the loading amount of the N / C@Ni material on the base paper is 1-2 mg / cm 2 ; The thickness of the base material of the gas diffusion layer is 50-80μm.

9. A base material for a gas diffusion layer, characterized in that: The method is prepared by any one of claims 1 to 8.

10. Use of the matrix material of the gas diffusion layer according to claim 9 in a polymer electrolyte membrane fuel cell.

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