A composite material proton exchange membrane for methanol fuel cells and a method for preparing the same

Abstract

The present application relates to the technical field of fuel cell materials, and particularly relates to a composite material proton exchange membrane for methanol fuel cells and a preparation method thereof.The present application prepares a base film by using sulfonated polyether ether ketone and chitosan-coated WO3 nanoparticle materials through a flow casting film method, then sequentially applies an intermediate transition layer and a perfluorosulfonic acid polymer layer on the base film by using sulfonated polyether ether ketone / perfluorosulfonic acid polymer resin as raw materials through a thermal spraying assisted technology, and finally forms the composite material proton exchange membrane.The highest power of the composite material proton exchange membrane is nearly 1 times higher than that of a commercialized Nafion212 membrane, the methanol permeability is reduced by more than 70%, and the durability is increased by 6-7 times compared with that of a pure SPEEK membrane.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fuel cell materials, in particular to a composite material proton exchange membrane for methanol fuel cell and a preparation method thereof. BACKGROUND

[0002] Proton exchange membrane fuel cell has the advantages of small volume, light weight, high power density, fast start, no noise, zero pollution, etc., and has broad application prospects, especially suitable for electric vehicle power supply. In addition, it can also be used for civil fixed power generation system such as urban clean power station, military power generation system such as submarine power supply. Proton exchange membrane is the core component of proton exchange membrane fuel cell, and its performance directly affects the working performance of the fuel cell, so the research on proton exchange membrane material has become one of the hotspots of fuel cell research.

[0003] At present, whether it is H2 / O2 fuel cell PEMFC or direct methanol fuel cell DMFC, almost all use Nafion series membranes produced by DuPont Company of USA, as described in CN101355166A. Although Nafion perfluorosulfonic acid membrane has the advantages of high mechanical strength, good chemical stability, high proton conductivity (when containing a large amount of water), etc., but its high cost, high production technology threshold, large methanol permeability and other shortcomings greatly limit the application of fuel cells, especially the application of methanol fuel cell DMFC. Therefore, the development of new proton exchange membrane with excellent conductivity, low cost and low methanol permeability is the current research focus. SUMMARY

[0004] The present application provides a low-cost and high-stability organic polymer / inorganic nanoparticle composite proton exchange membrane for methanol fuel cell and a preparation method thereof. The composite membrane includes a base film composed of sulfonated polyether ether ketone material, chitosan and WO3 nanoparticles, a perfluorosulfonic acid polymer resin layer and an intermediate transition layer. The method uses inexpensive sulfonated polyether ether ketone material, chitosan and WO3 nanoparticle material as the base film, and coats a perfluorosulfonic acid polymer resin layer with high stability on the base film by thermal spraying assisted technology. The intermediate transition layer between the base film and the perfluorosulfonic acid polymer resin layer is a mixture of sulfonated polyether ether ketone and perfluorosulfonic acid polymer resin.

[0005] The sulfonated polyether ether ketone material has good compatibility with chitosan and WO3 nanoparticles, and forms a base film with good dispersity and uniformity. The intermediate transition layer can slow down the incompatibility between the base film and the perfluorosulfonic acid polymer resin layer. The composite film prepared by the method greatly reduces the cost of the proton exchange membrane, has low methanol permeability, and has higher performance than the Nafion212 membrane. The stability under a certain current density is greatly improved compared with the pure SPEEK (sulfonated polyether ether ketone) membrane.

[0006] Specifically, the first aspect of the present application provides a preparation method of a composite proton exchange membrane for a methanol fuel cell, comprising the following steps:

[0007] S1, preparing chitosan-coated WO3 nanoparticles;

[0008] S2, preparing a casting solution with sulfonated polyether ether ketone and chitosan-coated WO3 nanoparticle material, and preparing a base film by a casting film method;

[0009] S3, preparing a sulfonated polyether ether ketone / perfluorosulfonic acid polymer resin spraying solution, and coating an intermediate transition layer on the base film by a thermal spraying auxiliary technology;

[0010] S4, preparing a perfluorosulfonic acid polymer resin spraying solution, coating a high-stability perfluorosulfonic acid polymer resin layer on the intermediate transition layer film by a thermal spraying auxiliary technology, and then drying and cooling to obtain a composite proton exchange membrane for a methanol fuel cell.

[0011] Preferably, the thickness of the base film is 10-20 μm, the thickness of the intermediate transition layer is 5-15 μm, and the thickness of the perfluorosulfonic acid polymer resin layer is 10-20 μm.

[0012] Preferably, the degree of deacetylation of the chitosan is greater than 90%, and the weight average molecular weight is greater than 100,000; as an embodiment, the chitosan is purchased from Sigma Aldrich-419419.

[0013] Preferably, the diameter of the WO3 nanoparticles is less than 100 nm; as an embodiment, the WO3 nanoparticles are purchased from Sigma Aldrich-550086.

[0014] Preferably, the mass ratio of the chitosan and the WO3 nanoparticles is (5-30):1.

[0015] Further preferably, the mass ratio of the chitosan and the WO3 nanoparticles is 10:1.

[0016] Further preferably, the preparation method of the chitosan-coated WO3 nanoparticles comprises: dissolving the chitosan and the WO3 nanoparticles in an aprotic solvent, and performing ultrasonic dispersion treatment by a pulse ultrasonic disperser to obtain the chitosan-coated WO3 nanoparticles, and the mass concentration of the chitosan-coated WO3 nanoparticle mixture is 10%-20%.

[0017] Preferably, the aprotic solvent comprises one of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc) and N-methyl-2-pyrrolidone (NMP).

[0018] Preferably, the ultrasonic dispersion treatment has a power of 1000 W, a treatment temperature of 40-80 ℃ and a treatment time of 6-12 h.

[0019] Preferably, the mass ratio of the sulfonated polyether ether ketone to the chitosan-coated WO3 nanoparticles is (3-10):1, and further preferably, the mass ratio is 5:1.

[0020] Preferably, the sulfonation degree of the sulfonated polyether ether ketone is 0.5-0.8.

[0021] In the present application, the sulfonated polyether ether ketone is prepared by a common sulfonation reaction in the art using polyether ether ketone as a raw material, and the polyether ether ketone is preferably purchased from Sigma Aldrich, and the structural formula of the sulfonated polyether ether ketone is as follows:

[0022]

[0023] wherein n=50-120.

[0024] Further preferably, the preparation method of the base film comprises: dissolving the sulfonated polyether ether ketone and the chitosan-coated WO3 nanoparticles in an aprotic solvent, preparing a uniform mixture by ultrasonic dispersion to form a uniform casting solution, and the mass concentration of the casting solution is 5%-15%, and the casting solution is cast on a polytetrafluoroethylene template in an oven, the oven temperature is 70-120 ℃, and the treatment time is 6-12 h.

[0025] Preferably, the sulfonated polyether ether ketone / perfluorosulfonic acid polymer resin spraying solution comprises the sulfonated polyether ether ketone and the perfluorosulfonic acid polymer resin, and the mass ratio of the two is (1-2):(2-1), the solvent in the sulfonated polyether ether ketone / perfluorosulfonic acid polymer resin spraying solution is an aprotic solvent, and the thermal spraying temperature of the sulfonated polyether ether ketone / perfluorosulfonic acid polymer resin spraying solution on the base film is 70-85 ℃.

[0026] In the present application, the perfluorosulfonic acid polymer resin is a polymer with long side chains, and the structural formula of the perfluorosulfonic acid polymer resin is as follows:

[0027]

[0028] wherein x = 10-30, y = 1, z = 1, m = 2.

[0029] As an implementable case, the perfluorosulfonic acid polymer resin includes the Nafion™ perfluorosulfonic acid resin series products of DuPont Company.

[0030] Preferably, the thermal spraying temperature in the S3 step is 40-80℃.

[0031] Preferably, the thermal spraying temperature in the S4 step is 40-80℃, the drying temperature is 70-120℃, the drying time is 6-24h, and the cooling temperature is room temperature 25℃.

[0032] The second aspect of the present application provides a methanol fuel cell composite material proton exchange membrane prepared by the preparation method of the methanol fuel cell composite material proton exchange membrane. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 FIG. 1 is a structural schematic diagram of the methanol fuel cell composite material proton exchange membrane prepared in Example 1, wherein 1 is a base film, 2 is an intermediate transition layer, and 3 is a perfluorosulfonic acid polymer resin layer.

[0034] Figure 2 FIG. 2 is an SEM image of the base film in Example 2, with a scale of 5 μm.

[0035] Figure 3 FIG. 3 is a graph of the relationship between the power density and the current density obtained by testing the battery assembled by the Nafion 212 membrane in Example 2 and Comparative Example 4.

[0036] ADVANTAGEOUS EFFECTS

[0037] (1) The methanol fuel cell organic polymer / inorganic nanoparticle composite material membrane prepared by the present application can effectively slow down the degradation of the sulfonated polyether ether ketone membrane on the cathode side when applied in a single cell.

[0038] (2) The intermediate transition layer in the present application effectively reduces the incompatibility between the sulfonated polyether ether ketone and the perfluorosulfonic acid polymer resin membrane.

[0039] (3) The present application uses thermal spraying technology in the preparation process, which facilitates the preparation of each layer of membrane and the control of the membrane thickness.

[0040] (4) The composite material membrane preparation method provided by the present application can greatly reduce the production cost, and the methanol permeability of the composite material membrane is low, the energy density is high, and the performance is higher than that of the Nafion 212 membrane. The stability under a certain current density is greatly improved compared with the pure SPEEK proton exchange membrane.

[0041] (5) The raw material sulfonated polyether ether ketone material in the application has good compatibility with chitosan and WO3 nanoparticles, and forms a base film with good dispersity and uniformity, and the corresponding prepared composite material film has a long service life, which can reach more than 4500 h. DETAILED DESCRIPTION

[0042] Example 1

[0043] The first aspect of the example provides a preparation method of a composite material proton exchange membrane for a methanol fuel cell, which consists of the following steps:

[0044] S1, chitosan powder 15 g and WO3 nanoparticles 15 g are dissolved in 110 g aprotic solvent DMF, and the chitosan-coated WO3 nanoparticles are prepared by ultrasonic dispersion at 50℃ for 8 h through a pulse ultrasonic disperser with a power of 1000 W, and the mass concentration of the chitosan-coated WO3 nanoparticles is 12% (after the coating operation is completed, part of the uncompleted coating material will be removed, and the mass concentration of the chitosan-coated WO3 nanoparticles is controlled to be 12%);

[0045] S2, chitosan-coated WO3 nanoparticles with a solid content of 1 g (the solid content is a known mass concentration, which is taken according to the weight of the solution, and here 8.33 g of chitosan-coated WO3 nanoparticle solution is taken), sulfonated polyether ether ketone with a sulfonation degree of 0.55 5 g are dissolved in 52.67 g DMF, and a uniform casting solution is formed by ultrasonic dispersion at 50℃, and the mass concentration of the casting solution is 10% (the mass of DMF is controlled to control the mass concentration of the polymer in the casting solution), and the base film is obtained by casting on a polytetrafluoroethylene template in an oven; the temperature of the oven is 80℃, and the treatment time is 12 h;

[0046] S3, sulfonated polyether ether ketone and perfluoro sulfonic acid polymer resin are mixed in a mass ratio of 1:1 and dissolved in aprotic solvent DMF, so that the mass concentration of the sulfonated polyether ether ketone / perfluoro sulfonic acid polymer resin spraying solution is 10% (the mass of DMF is controlled so that the total amount of sulfonated polyether ether ketone and perfluoro sulfonic acid polymer resin accounts for 10% of the mass of the sulfonated polyether ether ketone / perfluoro sulfonic acid polymer resin spraying solution system), and the sulfonated polyether ether ketone / perfluoro sulfonic acid polymer resin spraying solution is prepared, and the intermediate transition layer is formed on the base film by using a spray gun through thermal spraying auxiliary technology, and the thermal spraying temperature is 80℃;

[0047] S4, the perfluorosulfonic acid polymer resin is dissolved in aprotic solvent DMF, the mass concentration of the perfluorosulfonic acid polymer resin is controlled to be 10%, a perfluorosulfonic acid polymer resin spraying liquid is prepared, a high-stability perfluorosulfonic acid polymer resin layer is formed on the intermediate transition layer film by using a spray gun through thermal spraying auxiliary technology, the thermal spraying temperature is 80℃; then the perfluorosulfonic acid polymer resin layer is dried at 90℃ for 24h, and cooled to room temperature 25℃, thereby obtaining the composite proton exchange membrane for methanol fuel cell.

[0048] The thickness of each layer is: base film 16 μm, intermediate transition layer 7 μm, perfluorosulfonic acid polymer resin layer 19 μm.

[0049] The chitosan is Sigma Aldrich-419419.

[0050] The WO3 nanoparticles are Sigma Aldrich-550086.

[0051] The sulfonated polyether ether ketone is prepared by sulfonation reaction of polyether ether ketone, and the polyether ether ketone is purchased from Sigma Aldrich.

[0052] The perfluorosulfonic acid polymer resin is Nafion™ perfluorosulfonic acid resin series products of DuPont company.

[0053] The second aspect of the example provides a composite proton exchange membrane for methanol fuel cell, and a structural schematic diagram is shown in Figure 1 , wherein: 1, base film; 2, intermediate transition layer; 3, perfluorosulfonic acid polymer resin layer.

[0054] It is detected that the proton conductivity of the proton exchange membrane is 2.5×10 -1 S / cm, the highest use temperature is 150 o C, the service life is 4500h, and the methanol permeation coefficient is 0.23×10 -6 S / cm. 2 The composite membrane is assembled into a single cell for testing, and the polarization curve of the single cell can measure that the highest power density of the composite membrane can reach 1.6W•cm -2 , which is far more than the cell performance of Nafion212 membrane (the highest power density can reach 0.9W•cm -2 ), and the voltage of the single cell can still be maintained at 0.63V at 1000mA•cm -2 for 90h, which is 6.43 times higher than the durability of the pure SPEEK membrane cell.

[0055] Example 2

[0056] The first aspect of the example provides a preparation method of a composite material proton exchange membrane for a methanol fuel cell, which consists of the following steps:

[0057] S1, 15 g of chitosan powder and 15 g of WO3 nanoparticles are dissolved in 110 g of aprotic solvent DMF, and dispersed by a pulse ultrasonic disperser at 50°C for 8 h, with a power of 1000 W, to prepare chitosan-coated WO3 nanoparticles, and the mass concentration of the chitosan-coated WO3 nanoparticles is 12% (after the coating operation, part of the uncompleted coating material is removed, and the mass concentration of the chitosan-coated WO3 nanoparticles is controlled to be 12%);

[0058] S2, 5 g of sulfonated polyether ether ketone with a sulfonation degree of 0.8 is dissolved in 52.67 g of DMF, and uniformly dispersed by ultrasonic dispersion at 50°C, to form a casting solution with a mass concentration of 10%, and the casting solution is cast on a polytetrafluoroethylene template in an oven to form a base film; the temperature of the oven is 80°C, and the treatment time is 12 h;

[0059] S3, the sulfonated polyether ether ketone and the perfluorosulfonic acid polymer resin are mixed in a mass ratio of 1:2 and dissolved in aprotic solvent DMF, to prepare a sulfonated polyether ether ketone / perfluorosulfonic acid polymer resin spraying solution with a mass concentration of 10%, and a spray gun is used to coat the base film to form an intermediate transition layer by using a thermal spraying assisted technology, and the thermal spraying temperature is 80°C;

[0060] S4, the perfluorosulfonic acid polymer resin is dissolved in aprotic solvent DMF, and the mass concentration of the perfluorosulfonic acid polymer resin is controlled to be 10% to prepare a perfluorosulfonic acid polymer resin spraying solution, and a spray gun is used to coat the intermediate transition layer film to form a perfluorosulfonic acid polymer resin layer with high stability by using a thermal spraying assisted technology, and the thermal spraying temperature is 80°C; then the perfluorosulfonic acid polymer resin layer is dried at 90°C for 24 h, and cooled to room temperature 25°C, to obtain a composite material proton exchange membrane for a methanol fuel cell.

[0061] The thickness of each layer is as follows: the base film is 16 μm, the intermediate transition layer is 6 μm, and the perfluorosulfonic acid polymer resin layer is 18 μm.

[0062] The chitosan is Sigma Aldrich-419419.

[0063] The WO3 nanoparticles are Sigma Aldrich-550086.

[0064] The sulfonated polyether ether ketone is prepared by sulfonation of polyether ether ketone, and the polyether ether ketone is purchased from Sigma Aldrich.

[0065] The perfluorosulfonic acid polymer resin is a Nafion™ perfluorosulfonic acid resin series product of DuPont Company.

[0066] The second aspect of the example provides a composite proton exchange membrane for a methanol fuel cell.

[0067] The SEM image of the base membrane in the example is shown in Figure 2 , wherein the scale is 5 μm.

[0068] It is detected that the proton conductivity of the composite proton exchange membrane is 4.5×10 -1 S / cm, the highest use temperature is 150 o C, the service life is 4800 h, and the methanol permeation coefficient is 0.20×10 -6 S / cm 2 . The composite proton exchange membrane is assembled into a single cell for testing, and the polarization curve of the single cell can measure that the highest power density of the composite membrane can reach 1.8 W•cm -2 , which is far more than the cell performance of the Nafion212 membrane (the highest power density can reach 0.9 W•cm -2 ), and the voltage of the single cell can still be maintained at 0.63 V under 1000 mA•cm -2 for 90 h, which is 6.42 times higher than the durability of the pure SPEEK membrane cell.

[0069] Example 3

[0070] The first aspect of the example provides a preparation method of a composite proton exchange membrane for a methanol fuel cell, which consists of the following steps:

[0071] S1, 15 g of chitosan powder and 15 g of WO3 nanoparticles are dissolved in 110 g of aprotic solvent DMF, and the chitosan-coated WO3 nanoparticles are prepared by ultrasonic dispersion at 50°C for 8 h through a pulse ultrasonic disperser with a power of 1000 W, and the mass concentration of the chitosan-coated WO3 nanoparticles is 12% (after the coating operation, part of the uncompleted coated substances are removed, and the mass concentration of the chitosan-coated WO3 nanoparticles is controlled to be 12%);

[0072] S2, 5 g of sulfonated polyether ether ketone with a sulfonation degree of 0.7 is dissolved in 52.67 g of DMF, and a uniform casting solution is formed by ultrasonic dispersion at 50°C, and the mass concentration of the casting solution is 10%, and the base membrane is obtained by casting the film on a polytetrafluoroethylene template in an oven; wherein the oven temperature is 80°C, and the treatment time is 12 h;

[0073] S3, sulfonated polyether ether ketone and perfluorosulfonic acid polymer resin are mixed in a mass ratio of 2:1 in aprotic solvent DMF, to ensure the mass concentration of sulfonated polyether ether ketone / perfluorosulfonic acid polymer resin spraying liquid is 10%, to prepare sulfonated polyether ether ketone / perfluorosulfonic acid polymer resin spraying liquid, to form an intermediate transition layer on the base film by using a spray gun through thermal spraying auxiliary technology, and the thermal spraying temperature is 80℃;

[0074] S4, perfluorosulfonic acid polymer resin is dissolved in aprotic solvent DMF, and the mass concentration of perfluorosulfonic acid polymer resin is controlled to be 10%, to prepare perfluorosulfonic acid polymer resin spraying liquid, to form a perfluorosulfonic acid polymer resin layer with high stability on the intermediate transition layer film by using a spray gun through thermal spraying auxiliary technology, and the thermal spraying temperature is 80℃; then the perfluorosulfonic acid polymer resin layer is dried at 90℃ for 24h, and cooled to room temperature 25℃, to obtain the composite proton exchange membrane for methanol fuel cell.

[0075] The thickness of each layer is: base film 17μm, intermediate transition layer 8μm, and perfluorosulfonic acid polymer resin layer 18μm.

[0076] The chitosan is Sigma Aldrich-419419.

[0077] The WO3 nanoparticles are Sigma Aldrich-550086.

[0078] The sulfonated polyether ether ketone is prepared by sulfonation reaction of polyether ether ketone, and the polyether ether ketone is purchased from Sigma Aldrich.

[0079] The perfluorosulfonic acid polymer resin is Nafion™ perfluorosulfonic acid resin series products of DuPont company.

[0080] The second aspect of the example provides a composite proton exchange membrane for methanol fuel cell.

[0081] It is detected that the proton conductivity of the composite proton exchange membrane is 3.5×10 -1 S / cm, the highest use temperature is 150 o C, the service life is 4800h, and the methanol permeation coefficient is 0.21×10 -6 S / cm 2 The composite proton exchange membrane is assembled into a single cell for testing, and the polarization curve of the single cell can measure that the highest power density of the composite membrane can reach 1.8W•cm -2 , which is far more than the cell performance of Nafion212 membrane (the highest power density can reach 0.9W•cm -2 ), and the single cell is 1000mA•cm -2The lower voltage can be maintained at 0.63V at 90h, and the durability is increased by 6.41 times compared with the battery of pure SPEEK film.

[0082] Comparative Example 1

[0083] The example provides a preparation method of a composite proton exchange membrane for a methanol fuel cell, which comprises the following steps:

[0084] S1, 1.5g of WO3 nanoparticles is dissolved in aprotic solvent DMF, and dispersed by a pulse ultrasonic disperser at 50℃ for 8h, the power of ultrasonic dispersion is 1000W, to prepare a nanoparticle mixture, the mass concentration of WO3 nanoparticles is 1%;

[0085] S2, 0.1g of the nanoparticle mixture, 5g of sulfonated polyether ether ketone with a sulfonation degree of 0.8 are dissolved in 41.0g of DMF, and uniformly cast into a casting solution by ultrasonic dispersion at 50℃, the mass concentration of the casting solution is 10%, and the casting film is cast on a polytetrafluoroethylene template in an oven, to obtain a base film; wherein the oven temperature is 80℃, and the treatment time is 12h;

[0086] S3, the sulfonated polyether ether ketone and the perfluorosulfonic acid polymer resin are mixed in a mass ratio of 1:2 and dissolved in aprotic solvent DMF, to prepare a sulfonated polyether ether ketone / perfluorosulfonic acid polymer resin spraying solution with a mass concentration of 10%, and a middle transition layer is formed on the base film by using a spray gun through thermal spraying assisted technology, and the thermal spraying temperature is 80℃;

[0087] S4, the perfluorosulfonic acid polymer resin is dissolved in aprotic solvent DMF, and the mass concentration of the perfluorosulfonic acid polymer resin is controlled to be 10%, to prepare a perfluorosulfonic acid polymer resin spraying solution, and a high-stability perfluorosulfonic acid polymer resin layer is formed on the middle transition layer film by using a spray gun through thermal spraying assisted technology, and the thermal spraying temperature is 80℃; then the sample is dried at 90℃ for 24h, and cooled to room temperature 25℃, to obtain a composite proton exchange membrane for a methanol fuel cell.

[0088] The thickness of each layer is: the base film is 16μm, the middle transition layer is 6μm, and the perfluorosulfonic acid polymer resin layer is 18μm.

[0089] The WO3 nanoparticles are Sigma Aldrich-550086.

[0090] The sulfonated polyether ether ketone is prepared by sulfonation reaction of polyether ether ketone, and the polyether ether ketone is purchased from Sigma Aldrich.

[0091] The perfluorosulfonic acid polymer resin is a Nafion™ perfluorosulfonic acid resin series product of DuPont Company.

[0092] The proton conductivity of the composite proton exchange membrane is 1.1×10 -1 S / cm, the highest use temperature is 150 o C, the service life is 4000h, and the methanol permeation coefficient is 0.82×10 -6 S / cm 2 The composite proton exchange membrane is assembled into a single cell for testing, and the polarization curve of the single cell can measure that the highest power density of the composite membrane can reach 0.7W•cm -2 , which is far more than the battery performance of the Nafion212 membrane (the highest power density can reach 0.9W•cm -2 ), and the voltage of the single cell can still be maintained at 0.63V under 1000mA•cm -2 for 90h, which is significantly improved compared with the battery of the pure SPEEK membrane.

[0093] Comparative Example 2

[0094] The example provides a preparation method of a composite proton exchange membrane for a methanol fuel cell, which comprises the following steps:

[0095] S1, 15g of chitosan powder is dissolved in 110g of aprotic solvent DMF, and is dispersed by a pulse ultrasonic disperser at 50°C for 8h, the power of the ultrasonic dispersion is 1000W, to prepare a chitosan solution, and the mass concentration of the chitosan is 12% (after the coating operation is completed, part of the uncompleted coating material is removed, and the mass concentration of the chitosan coated WO3 nanoparticles is controlled to be 12%);

[0096] S2, 5g of sulfonated polyether ether ketone with a sulfonation degree of 0.8 is taken out from the chitosan solution with a solid content of 1g, and is dissolved in 52.67g of DMF to form a uniform casting solution by ultrasonic dispersion at 50°C, and the mass concentration of the casting solution is 10%, and the casting film is cast on a polytetrafluoroethylene template in an oven, to obtain a base film; wherein the temperature of the oven is 80°C, and the treatment time is 12h;

[0097] S3, the sulfonated polyether ether ketone and the perfluorosulfonic acid polymer resin are mixed in a mass ratio of 1:2 and dissolved in aprotic solvent DMF, to ensure that the mass concentration of the sulfonated polyether ether ketone / perfluorosulfonic acid polymer resin spraying solution is 10%, and the sulfonated polyether ether ketone / perfluorosulfonic acid polymer resin spraying solution is prepared, and the intermediate transition layer is formed on the base film by using a spray gun through a thermal spraying auxiliary technology, and the thermal spraying temperature is 80°C;

[0098] S4, the perfluorosulfonic acid polymer resin is dissolved in aprotic solvent DMF, the mass concentration of the perfluorosulfonic acid polymer resin is controlled to be 10%, a perfluorosulfonic acid polymer resin spraying liquid is prepared, a high-stability perfluorosulfonic acid polymer resin layer is formed on the intermediate transition layer film by using a spray gun through thermal spraying auxiliary technology, the thermal spraying temperature is 80℃; then the perfluorosulfonic acid polymer resin layer is dried at 90℃ for 24h, and cooled to room temperature 25℃, thereby obtaining the composite proton exchange membrane for methanol fuel cell.

[0099] The thickness of each layer is: base film 16μm, intermediate transition layer 6μm, perfluorosulfonic acid polymer resin layer 18μm.

[0100] The chitosan is Sigma Aldrich-419419.

[0101] The sulfonated polyether ether ketone is prepared by sulfonation reaction of polyether ether ketone, and the polyether ether ketone is purchased from Sigma Aldrich.

[0102] The perfluorosulfonic acid polymer resin is Nafion™ perfluorosulfonic acid resin series products of DuPont company.

[0103] It is detected that the proton conductivity of the composite proton exchange membrane is 0.9×10 -1 S / cm, the highest use temperature is 150 o C, the service life is 4000h, and the methanol permeation coefficient is 0.76×10 -6 S / cm 2 The composite proton exchange membrane is assembled into a single cell for testing, and the polarization curve of the single cell can measure that the highest power density of the composite membrane can reach 0.5W•cm -2 , which is far more than the battery performance of Nafion212 membrane (the highest power density can reach 0.9W•cm -2 ), and the voltage of the single cell can still be maintained at 0.63V at 1000mA•cm -2 for 90h, and the durability of the single cell is improved significantly compared with the pure SPEEK membrane cell.

[0104] Comparative Example 3

[0105] The example provides a preparation method of a composite proton exchange membrane for methanol fuel cell, which comprises the following steps:

[0106] S1, 15 g of chitosan powder and 15 g of WO3 nanoparticles were dissolved in 110 g of aprotic solvent DMAc, and dispersed by a pulse ultrasonic disperser at 50℃ for 8 h, with a power of 1000 W, to prepare chitosan-coated WO3 nanoparticles, with a mass concentration of 12% (after the coating operation, part of the uncompleted coating material was removed, and the mass concentration of the chitosan-coated WO3 nanoparticles was controlled to be 12%);

[0107] S2, 5 g of sulfonated polyether ether ketone with a sulfonation degree of 0.8 was dissolved in 54.33 g of DMAc, and a uniform casting solution was formed by ultrasonic dispersion at 50℃, with a mass concentration of 10%, and a base film was obtained by casting the casting solution on a polytetrafluoroethylene template in an oven; the oven temperature was 80℃, and the treatment time was 12 h;

[0108] S3, sulfonated polyether ether ketone and perfluorosulfonic acid polymer resin were mixed in a mass ratio of 1:2 and dissolved in aprotic solvent DMAc, to prepare a sulfonated polyether ether ketone / perfluorosulfonic acid polymer resin spraying solution with a mass concentration of 10%, and an intermediate transition layer was formed on the base film by using a spray gun through thermal spraying assisted technology, with a thermal spraying temperature of 80℃;

[0109] S4, perfluorosulfonic acid polymer resin was dissolved in aprotic solvent DMF, and the mass concentration of the perfluorosulfonic acid polymer resin was controlled to be 10%, to prepare a perfluorosulfonic acid polymer resin spraying solution, and a high-stability perfluorosulfonic acid polymer resin layer was formed on the intermediate transition layer by using a spray gun through thermal spraying assisted technology, with a thermal spraying temperature of 80℃; then, the sample was dried at 90℃ for 24 h, and cooled to room temperature of 25℃, to obtain a composite proton exchange membrane for methanol fuel cells.

[0110] The thickness of each layer was: base film 17 μm, intermediate transition layer 7 μm, and perfluorosulfonic acid polymer resin layer 19 μm.

[0111] The chitosan was Sigma Aldrich-419419.

[0112] The WO3 nanoparticles were Sigma Aldrich-550086.

[0113] The sulfonated polyether ether ketone was prepared by sulfonation of polyether ether ketone, and the polyether ether ketone was purchased from Sigma Aldrich.

[0114] The perfluorosulfonic acid polymer resin was a product of Nafion™ perfluorosulfonic acid resin series from DuPont.

[0115] The proton conductivity of the composite proton exchange membrane is 4.5 x 10 -1 S / cm, the maximum use temperature is 150 o C, the service life is 4800 h, and the methanol permeation coefficient is 0.21 x 10 -6 S / cm 2 The composite proton exchange membrane is assembled into a single cell for testing, and the polarization curve of the single cell can measure that the maximum power density of the composite membrane can reach 1.8 W•cm -2 , which is much higher than the battery performance of the Nafion212 membrane (the maximum power density can reach 0.9 W•cm -2 ), and the voltage of the single cell can be maintained at 0.63 V at 1000 mA•cm -2 for 90 h, which is 6.4 times higher than the durability of the pure SPEEK membrane battery, and the membranes prepared by different solvents have no significant effect on the performance.

[0116] Comparative Example 4

[0117] The example provides a proton exchange membrane, which is a Nafion212 membrane produced by the United States DuPont Company.

[0118] The proton conductivity of the proton exchange membrane is 7.7 x 10 -1 S / cm, the maximum use temperature is 150 o C, the service life is 4500 h, and the methanol permeation coefficient is 1.4 x 10 -6 S / cm 2 The membrane is assembled into a single cell for testing, and the polarization curve of the single cell can measure that the maximum power density of the membrane can reach 0.9 W•cm -2 , and the voltage of the single cell can be maintained at 0.63 V at 1000 mA•cm -2 for 60 h, but the methanol permeation is obvious during long-term use, and the battery power continues to decrease.

[0119] The relationship between the power density and the current density obtained by testing the batteries assembled by the proton exchange membrane obtained in Example 2 and the Nafion212 membrane in Comparative Example 4 is shown in Figure 3 .

[0120] Comparative Example 5

[0121] The example provides a preparation method of a pure SPEEK proton exchange membrane for a methanol fuel cell, which comprises the following steps:

[0122] Sulfonated polyether ether ketone with sulfonation degree of 0.8, 5g, was dissolved in DMF, dispersed by ultrasonic at 50℃ to form a uniform casting solution with mass concentration of 10%, and then casted on a polytetrafluoroethylene template in an oven to obtain a base film; the temperature of the oven was 80℃, the treatment time was 12h, and then cooled to room temperature 25℃ to obtain a pure SPEEK proton exchange membrane with a thickness of 42μm.

[0123] The sulfonated polyether ether ketone is prepared by sulfonation of polyether ether ketone, which is purchased from Sigma Aldrich.

[0124] It is detected that the proton conductivity of the proton exchange membrane is 4.1×10 -1 S / cm, and the methanol permeation coefficient is 0.21×10 -6 S / cm 2 The membrane is assembled into a single cell for testing, and the single cell can maintain a voltage of 0.63V at 1000mA•cm -2 -2 only for 14h, and the durability is general.

[0125] Performance test

[0126] Test object: the corresponding proton exchange membranes of examples 1-3, comparative examples 1-2 and comparative example 4

[0127] Test item and result: see table 1

[0128] Table 1

[0129]

Claims

1. A method for preparing a composite proton exchange membrane for a methanol fuel cell, characterized by, The preparation method comprises the following steps: S1, preparing chitosan-coated WO3 nanoparticles; S2, preparing a casting solution of sulfonated polyether ether ketone and the chitosan-coated WO3 nanoparticles, and preparing a base film through a flow casting method; S3, preparing a sulfonated polyether ether ketone / perfluoro sulfonic acid polymer resin spraying solution, and coating an intermediate transition layer on the base film through a thermal spraying auxiliary technology; S4, preparing a perfluoro sulfonic acid polymer resin spraying solution, coating a perfluoro sulfonic acid polymer resin layer with high stability on the intermediate transition layer film through a thermal spraying auxiliary technology, and then drying and cooling to obtain the composite proton exchange membrane. The base film has a thickness of 10-20 μm, the intermediate transition layer has a thickness of 5-15 μm, and the perfluoro sulfonic acid polymer resin layer has a thickness of 10-20 μm.

2. The method for preparing a composite material proton exchange membrane for a methanol fuel cell according to claim 1, characterized by, The chitosan has a deacetylation degree greater than 90% and a weight average molecular weight greater than 100,000, and the WO3 nanoparticles have a diameter less than 100 nm.

3. The method for preparing a composite material proton exchange membrane for a methanol fuel cell according to claim 2, characterized by, The sulfonated polyether ether ketone has a sulfonation degree of 0.5-0.8 and a structural formula of: ，n=50-120。 4. The method for preparing a composite material proton exchange membrane for a methanol fuel cell according to claim 3, characterized by, The preparation method of the chitosan-coated WO3 nanoparticles comprises the following steps: dissolving chitosan and WO3 nanoparticles in an aprotic solvent, and performing ultrasonic dispersion treatment to obtain the chitosan-coated WO3 nanoparticles.

5. The method for preparing a composite proton exchange membrane for a methanol fuel cell according to claim 4, characterized by, The aprotic solvent comprises one of N,N-dimethylformamide, N,N-dimethylacetamide or N-methyl-2-pyrrolidone.

6. The method for preparing a composite material proton exchange membrane for a methanol fuel cell according to claim 5, characterized by, The mass ratio of the sulfonated polyether ether ketone to the chitosan-coated WO3 nanoparticles is (3-10):

1.

7. The method for preparing a composite material proton exchange membrane for a methanol fuel cell according to claim 6, characterized by, The sulfonated polyether ether ketone / perfluoro sulfonic acid polymer resin spraying solution comprises sulfonated polyether ether ketone and perfluoro sulfonic acid polymer resin, and the mass ratio of the two is (1-2):(2-1).

8. The method for preparing a composite material proton exchange membrane for a methanol fuel cell according to claim 7, characterized by, The perfluoro sulfonic acid polymer resin has a structural formula of: wherein x=10-30, y=1, z=1, and m=2.

9. A composite proton exchange membrane for a methanol fuel cell, which is prepared by the preparation method of the composite proton exchange membrane for a methanol fuel cell according to claim 8.

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