A substrate material for gas diffusion layers and its use in polymer electrolyte membrane fuel cells

Abstract

The application provides a kind of gas diffusion layer base material and its application in polymer electrolyte membrane fuel cell, the preparation of base material includes the following steps: S1, graphene oxide is added to n-hexane, nanofibrous iron-nickel alloy powder and melamine are stirred, the solution is moved to high-pressure reactor for hydrothermal reaction, calcination is carried out under inert gas atmosphere, product is obtained, the product is stirred in hydrochloric acid solution, filtration and washing are carried out, and N / C@Ni material is obtained;S2, short carbon fiber, modified polyurethane and adhesive are prepared into raw paper by dry papermaking or wet papermaking;S3, N / C@Ni material is added to anhydrous ethanol to obtain a solution, the raw paper of S2 is immersed in the solution, vacuum treatment, hot pressing, carbonization, and the target gas diffusion layer base material is obtained.The gas diffusion layer base material of the application has the characteristics of thin thickness and stable structure, can reduce the waterlogging phenomenon of fuel cell, improve the mass transfer capacity, and has good application prospect.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to a matrix material for a gas diffusion layer and its application in polymer electrolyte membrane fuel cells. Background Technology

[0002] The core component of a proton exchange membrane fuel cell (PEMFC) is the membrane electrode assembly (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 plates, plays a role in water vapor transport, electron conduction, and heat transfer. In the fuel cell, the GDL serves multiple functions, including supporting the catalyst layer, collecting current, conducting gas, and discharging water. It facilitates the redistribution of reactant gases and product water between the flow field and the catalyst layer, making it a key material affecting electrode performance. Generally, the gas diffusion layer is required to possess good electrical conductivity, hydrophobicity, permeability, and mechanical strength.

[0003] Currently, carbon paper is mainly used as the base layer for the gas diffusion layer of fuel cells. This is achieved by compounding carbon fibers, polymer fibers, and adhesives to form paper, which is then carbonized at 1600℃ to obtain carbon fiber paper. However, this method suffers from problems such as excessive thickness, brittleness, poor flexibility, and high energy consumption during production, resulting in gas diffusion layers with a thickness of around 200 μm. While methods using graphene, carbon nanotubes, and carbon black to directly prepare the gas diffusion layer can reduce its thickness, their low tensile strength severely limits its application.

[0004] In addition, the resistance of the gas diffusion layer is a characteristic parameter of the electron transport capability. As the electrochemical reaction proceeds, the reaction product water will accumulate near the cathode catalyst layer. This water will not only diffuse through the proton exchange membrane to the anode, but also diffuse through the cathode diffusion layer into the cathode flow field. If this liquid water cannot be transferred quickly, it will cause water accumulation in the diffusion layer, i.e., flooding.

[0005] Therefore, it is necessary to develop a matrix material for the gas diffusion layer that is thin, structurally stable, reduces flooding in fuel cells, 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 this invention is implemented as follows:

[0008] A method for preparing a matrix material for a gas diffusion layer includes the following steps:

[0009] S1. Add graphene oxide to n-hexane, add nanofiber iron-nickel alloy powder and melamine and stir. Transfer the solution to a high-pressure reactor for hydrothermal reaction and calcine under an inert gas atmosphere to obtain the product. Stir the product in hydrochloric acid solution, filter and wash to obtain N / C@Ni material.

[0010] S2. Short-cut carbon fibers, modified polyurethane, and adhesives are used to prepare base paper through dry or wet papermaking.

[0011] S3. Add the N / C@Ni material to anhydrous ethanol to obtain a solution. Impregnate the base paper from S2 in the solution, perform vacuum treatment, hot pressing, and carbonization to obtain the matrix material of the target gas diffusion layer.

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

[0013] Furthermore, in step S1, the hydrothermal reaction is carried out at a temperature of 140-180℃ for 12-24 hours; the calcination is carried out at 300-400℃ for 20-30 minutes, followed by calcination at 500-600℃ 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 carried out at 100-200 rpm for 10-12 h.

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

[0016] Furthermore, the modified polyurethane is prepared by mixing and stirring amino-terminated polydimethylsiloxane and hexamethylene diisocyanate to obtain a material, and then reacting the material with pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propanediamine.

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

[0018] Furthermore, the adhesive is a mixture of 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 of the N / C@Ni material on the base paper is 1-2 mg / cm³. 2 The thickness of the substrate material of the gas diffusion layer is 50-80 μm.

[0020] A substrate material for a gas diffusion layer, prepared by the method described in any of the above-mentioned methods.

[0021] Application of a gas diffusion layer matrix material in polymer electrolyte membrane fuel cells.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[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 to avoid brittleness, and increasing the tensile strength of the base paper. Furthermore, the modified polyurethane of the present invention improves the hydrophobicity of the substrate, helping to prevent moisture accumulation.

[0024] 2. The N / C@Ni material of this invention forms a porous structure by acid etching nanofiber-iron alloy powder, increasing surface roughness and porosity. Encapsulating the porous nanofiber-like nickel powder within a carbonitriding material not only increases strength and improves thermal and electrical conductivity but also enhances resistance to electro-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 capacity and reducing flooding in fuel cells. Detailed Implementation

[0025] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.

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

[0027] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.

[0028] Example 1

[0029] A method for preparing a matrix material for a gas diffusion layer includes the following steps:

[0030] S1. Graphene oxide was added to n-hexane at a solid-liquid ratio of 1:15 g / mL, along with nanofiber iron-nickel alloy powder and melamine. The mixture was stirred, with a mass ratio of graphene oxide, nanofiber iron-nickel alloy powder, and melamine of 10:1.5:2. The solution was transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 140℃ for 12 hours. Calcination was then carried out under an inert gas atmosphere, specifically at 300℃ for 20 minutes, followed by calcination at 500℃ for 2 hours. The product was then cooled in the furnace to obtain the solid-liquid ratio of 1:15 g / mL. The product was then stirred in 0.05 mol / L hydrochloric acid solution at 100 rpm for 10 hours, filtered, and washed to obtain N / C@Ni material.

[0031] S2. Short-cut carbon fibers, modified polyurethane, and adhesives (polyacrylonitrile and hydroxypropyl methylcellulose in a mass ratio of 1:5:1) are mixed to prepare base paper by dry or wet papermaking.

[0032] The modified polyurethane is prepared by mixing and stirring amino-terminated polydimethylsiloxane and hexamethylene diisocyanate to obtain a material, and then reacting the material with pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propanediamine to obtain the modified polyurethane. The mass ratio of amino-terminated polydimethylsiloxane, hexamethylene diisocyanate, pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propanediamine 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. Impregnate the base paper from S2 in the solution, perform vacuum treatment, mix with phenolic resin, hot-press, and carbonize to obtain the matrix material for the target gas diffusion layer with a thickness of 50 μm. The loading of N / C@Ni material on the base paper is 1 mg / cm³. 2 .

[0034] Example 2

[0035] A method for preparing a matrix material for a gas diffusion layer includes the following steps:

[0036] S1. Graphene oxide was added to hexane at a solid-liquid ratio of 1:18 g / mL, followed by the addition of nanofiber iron-nickel alloy powder and melamine. The mass ratio of graphene oxide, nanofiber iron-nickel alloy powder, and melamine was 10:2:2.5. The solution was transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 160℃ for 18 hours. Calcination was then carried out under an inert gas atmosphere, specifically at 350℃ for 25 minutes, followed by calcination at 550℃ for 3 hours. The product was then cooled in the furnace to obtain the solid-liquid ratio of 1:20 g / mL. The product was then stirred at 150 rpm for 11 hours in a 0.06 mol / L hydrochloric acid solution, filtered, and washed to obtain the N / C@Ni material.

[0037] S2. Short-cut carbon fibers, modified polyurethane, and adhesives in a mass ratio of 1:8:1.5 are used to prepare base paper through dry or wet papermaking.

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

[0039] S3. N / C@Ni material was added to anhydrous ethanol at a solid-liquid ratio of 1:25 g / mL to obtain a solution. The base paper from S2 was impregnated in the solution, vacuum-treated, and then mixed with phenolic resin, hot-pressed, and carbonized to obtain the matrix material for the target gas diffusion layer with a thickness of 100 μm. The loading of N / C@Ni material on the base paper was 1.5 mg / cm³. 2 .

[0040] Example 3

[0041] A method for preparing a matrix material for a gas diffusion layer includes the following steps:

[0042] S1. Graphene oxide was added to hexane at a solid-liquid ratio of 1:20 g / mL, followed by the addition of nanofiber iron-nickel alloy powder and melamine. The mass ratio of graphene oxide, nanofiber iron-nickel alloy powder, and melamine was 10:2.8:3. The solution was transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 180°C for 24 hours. Calcination was then carried out under an inert gas atmosphere, specifically at 400°C for 30 minutes, followed by calcination at 600°C for 4 hours. The product was then cooled in the furnace to obtain the solid-liquid ratio of 1:25 g / mL. The product was then stirred at 200 rpm for 12 hours in a 0.07 mol / L hydrochloric acid solution, filtered, and washed to obtain N / C@Ni material.

[0043] S2. Short-cut carbon fibers, modified polyurethane, and adhesives in a mass ratio of 1:10:2 are used to prepare base paper through dry or wet papermaking.

[0044] The modified polyurethane is prepared by mixing and stirring amino-terminated polydimethylsiloxane and hexamethylene diisocyanate to obtain a material, and then reacting the material with pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propanediamine to obtain the modified polyurethane. The mass ratio of amino-terminated polydimethylsiloxane, hexamethylene diisocyanate, pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propanediamine 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. Impregnate the base paper from S2 in the solution, perform vacuum treatment, mix with phenolic resin, hot-press, and carbonize to obtain the matrix material for the target gas diffusion layer with a thickness of 150 μm. The loading of N / C@Ni material on the base paper is 2 mg / cm³. 2 .

[0046] Comparative Example 1

[0047] The difference from Example 2 is that nanofiber-like iron-nickel powder and carbon powder are mixed together, otherwise it is the same as Example 2.

[0048] The method for preparing the matrix material of the gas diffusion layer in this comparative example includes the following steps:

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

[0050] S2. Short-cut carbon fibers, modified polyurethane, and adhesives in a mass ratio of 1:8:1.5 are used to prepare base paper through dry or wet papermaking.

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

[0052] S3. Add nanofiber nickel powder and carbon powder (mass ratio 2:10) to anhydrous ethanol at a solid-liquid ratio of 1:25 g / mL to obtain a solution. Impregnate the base paper from S2 in this solution, perform vacuum treatment, mix with phenolic resin, hot-press, and carbonize to obtain the matrix material for the target gas diffusion layer, with a thickness of 100 μm. The loading of nanofiber nickel powder and carbon powder on the base paper is 1.5 mg / cm³. 2 .

[0053] Comparative Example 2

[0054] The difference from Example 2 is that step S1 is missing, but otherwise it is the same as Example 2.

[0055] The method for preparing the matrix material of the gas diffusion layer in this comparative example includes the following steps:

[0056] Short-cut carbon fibers, modified polyurethane, and adhesives in a mass ratio of 1:8:1.5 were mixed with phenolic resin, hot-pressed, and carbonized to obtain the matrix material for the gas diffusion layer with a thickness of 100 μm. The base paper was prepared by dry or wet papermaking.

[0057] The modified polyurethane is prepared by mixing and stirring amino-terminated polydimethylsiloxane and hexamethylene diisocyanate to obtain a material, and then reacting the material with pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propanediamine. The mass ratio of amino-terminated polydimethylsiloxane, hexamethylene diisocyanate, pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propanediamine is 1:1.5:0.6:0.4:0.02.

[0058] Comparative Example 3

[0059] The difference from Example 2 is that the modified polyurethane is missing in step S2, but otherwise it is the same as Example 2.

[0060] The method for preparing the matrix material of the gas diffusion layer in this comparative example includes the following steps:

[0061] S1. Graphene oxide was added to hexane at a solid-liquid ratio of 1:18 g / mL, followed by the addition of nanofiber iron-nickel alloy powder and melamine. The mass ratio of graphene oxide, nanofiber iron-nickel alloy powder, and melamine was 10:2:2.5. The solution was transferred to a high-pressure reactor and subjected to a hydrothermal reaction at 160℃ for 18 hours. Calcination was then carried out under an inert gas atmosphere, specifically at 350℃ for 25 minutes, followed by calcination at 550℃ for 3 hours. The product was then cooled in the furnace to obtain the solid-liquid ratio of 1:20 g / mL. The product was then stirred at 150 rpm for 11 hours in a 0.06 mol / L hydrochloric acid solution, filtered, and washed to obtain the N / C@Ni material.

[0062] S2. Short-cut carbon fibers and binders in a mass ratio of 1:1.5 are used to prepare base paper through dry or wet papermaking.

[0063] S3. N / C@Ni material was added to anhydrous ethanol at a solid-liquid ratio of 1:25 g / mL to obtain a solution. The base paper from S2 was impregnated in the solution, vacuum-treated, and then mixed with phenolic resin, hot-pressed, and carbonized to obtain the matrix material for the target gas diffusion layer with a thickness of 100 μm. The loading of N / C@Ni material on the base paper was 1.5 mg / cm³. 2 .

[0064] Comparative Example 4

[0065] The preparation method of the matrix material for the gas diffusion layer in this comparative example includes the following steps:

[0066] S1. Graphene oxide was added to n-hexane at a solid-liquid ratio of 1:18 g / mL, along with nickel nitrate and melamine. The mixture was stirred, with a mass ratio of graphene oxide, nickel nitrate, and melamine of 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. Calcination was then carried out under an inert gas atmosphere, specifically at 350°C for 25 minutes, followed by calcination at 550°C for 3 hours. The furnace was then cooled to obtain N / C@Ni material.

[0067] S2. Short-cut carbon fibers, modified polyurethane, and adhesives in a mass ratio of 1:8:1.5 are used to prepare base paper through dry or wet papermaking.

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

[0069] S3. N / C@Ni material was added to anhydrous ethanol at a solid-liquid ratio of 1:25 g / mL to obtain a solution. The base paper from S2 was impregnated in the solution, vacuum-treated, and then mixed with phenolic resin, hot-pressed, and carbonized to obtain the matrix material for the target gas diffusion layer with a thickness of 100 μm. The loading of N / C@Ni material on the base paper was 1.5 mg / cm³. 2 .

[0070] Test case

[0071] The matrix materials prepared in Examples 1-3 and Comparative Examples 1-4 were cut into 5cm×5cm pieces and their performance was tested.

[0072] Test indicators: 1. The air permeability of the sample is evaluated by testing the air permeability using a TQD-G1 air permeability tester in accordance with GB / T20042;

[0073] 2. The resistivity at 0.6 MPa was measured using a ZY9987 digital micro-ohmmeter to evaluate the conductivity of the sample;

[0074] 3. According to GB / T20042, the flexural strength and tensile strength are tested using a universal testing machine to evaluate the mechanical properties of the sample;

[0075] 4. The porosity of the experimental samples was calculated using the mercury porosimetry method to evaluate the mass transfer capacity of the samples.

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

[0077] Table 1

[0078]

[0079] As shown in Table 1, the matrix material of the gas diffusion layer prepared in this invention has good gas diffusivity, good electrical conductivity, excellent mechanical properties, high porosity to achieve good mass transfer effect, and good hydrophobicity. Compared with 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 within the protection scope of the present invention.

Claims

1. A method for preparing a matrix material for a gas diffusion layer, characterized in that, Includes the following steps: S1. Add graphene oxide to n-hexane, add nanofiber iron-nickel alloy powder and melamine and stir. Transfer the solution to a high-pressure reactor for hydrothermal reaction and calcine under an inert gas atmosphere to obtain the product. Stir the product in hydrochloric acid solution, perform acid etching, filter and wash to obtain porous N / C@Ni material. The mass ratio of graphene oxide, nanofiber iron-nickel alloy powder, and melamine is 10:1.5-2.8:2-3. S2. Short-cut carbon fibers, modified polyurethane, and adhesives are used to prepare base paper through dry or wet papermaking. The modified polyurethane is prepared by mixing and stirring amino-terminated polydimethylsiloxane and hexamethylene diisocyanate to obtain a material, and then reacting the material with pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propanediamine. The mass ratio of the amino-terminated polydimethylsiloxane, hexamethylene diisocyanate, pentaerythritol, polycarbonate diol, and N,N,N',N'-tetraethyl-1,3-propanediamine is 1:1-2:0.5-0.8:0.3-0.5:0.01-0.

03. S3. According to the solid-liquid ratio of 1:20-30 g / mL, N / C@Ni material is added to anhydrous ethanol to obtain a solution. The base paper of S2 is impregnated in the solution, vacuumed, mixed with phenolic resin, hot-pressed, and carbonized to obtain the matrix material of the target gas diffusion layer.

2. The method for preparing the matrix material as described in claim 1, characterized in that, In step S1, the solid-liquid ratio of graphene oxide to n-hexane is 1:15-20 g / mL.

3. The method for preparing the matrix material as described in claim 1, characterized in that, In step S1, the hydrothermal reaction is carried out at a temperature of 140-180℃ for 12-24 hours; the calcination is carried out at 300-400℃ for 20-30 minutes, followed by calcination at 500-600℃ for 2-4 hours.

4. The method for preparing the matrix material as described in claim 1, characterized in that, 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 carried out at 100-200 rpm for 10-12 h.

5. The method for preparing the matrix material as described in claim 1, characterized in that, In step S2, the mass ratio of the chopped carbon fiber, modified polyurethane, and adhesive is 1:5-10:1-2.

6. The method for preparing the matrix material as described in claim 5, characterized in that, The adhesive is a mixture of polyacrylonitrile and hydroxypropyl methylcellulose in a mass ratio of 1:1-3.

7. The method for preparing the matrix material as described in claim 1, characterized in that, In step S3, the loading of the N / C@Ni material on the base paper is 1-2 mg / cm³. 2 .

8. A matrix material for a gas diffusion layer, characterized in that, Prepared by the method described in any one of claims 1-7.

9. The application of the matrix material of the gas diffusion layer according to claim 8 in a polymer electrolyte membrane fuel cell.

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