Proton exchange membrane and preparation method and application thereof

Abstract

The invention belongs to the technical field of fuel cells, and particularly relates to a proton exchange membrane and a preparation method and application thereof. The preparation method of the proton exchange membrane comprises the following steps: enabling the proton exchange membrane body to be in contact with a treatment solvent at the temperature of 80-160 DEG C to obtain the proton exchange membrane, and enabling the proton exchange membrane body to be in contact with steam of the treatment solvent as a preferable implementation mode. The preparation method of the proton exchange membrane has the beneficial effects that a solvent high-temperature steam surface treatment technology is adopted, so that the surface structure and properties of the proton exchange membrane body are improved, the obstruction of the surface structure on proton conduction and water transmission is weakened or eliminated, and the water transmission and proton conduction capabilities of the proton exchange membrane are improved. Meanwhile, based on optimization and adjustment of the surface structure, formation of a uniform surface is promoted, and the hydrogen permeability of the proton exchange membrane is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of fuel cells, and in particular relates to a proton exchange membrane and a preparation method and application thereof. Background Art

[0002] As the core component of proton exchange membrane fuel cells, proton exchange membrane (PEM) plays the role of conducting protons, separating fuel and oxidant, isolating electrons, etc. There are many types of proton exchange membranes. According to the fluorine content, they can be divided into perfluorinated proton exchange membranes, partially fluorinated proton exchange membranes and non-fluorinated proton exchange membranes. The most widely used ones are Nafion produced by DuPont in the United States and GORE-SELECT perfluorosulfonic acid proton exchange membranes produced by Gore in the United States. Perfluorosulfonic acid is composed of hydrophobic fluorocarbon backbones and hydrophilic sulfonic acid groups with different polarities. In the water-containing state, the hydrophobic fluorocarbon backbone and the hydrophilic sulfonic acid groups will produce a microphase separation structure. The hydrophobic fluorocarbon backbone provides strength and stability for the proton exchange membrane, and the hydrophilic sulfonic acid group provides a continuous channel for proton migration. Perfluorosulfonic acid proton exchange membranes have good mechanical properties, high proton conductivity, good chemical and electrochemical stability. Among them, proton exchange membranes with high proton conductivity are one of the research hotspots, and the connection between perfluorosulfonic acid microstructure and proton exchange membrane performance has always been the focus of research.

[0003] The solution casting process is currently a more commonly used process for the commercialization of proton exchange membranes. In recent years, in order to reduce manufacturing costs and improve fuel cell performance, the thickness of the proton exchange membrane is required to be <30μm. Based on the solution casting process, the thickness of the proton exchange membrane can be thinner (5-25μm). The solution casting process has the advantage of a wide range of solvent selection. By using different solvent systems and membrane forming processes, the microstructure of the perfluorosulfonic acid proton exchange membrane can be effectively controlled. In the solution casting process, the microstructure of perfluorosulfonic acid depends to a large extent on the performance of the perfluorosulfonic acid solution. Previously, many researchers have regulated the aggregation structure of the perfluorosulfonic acid solution and the perfluorosulfonic acid polymer molecules in the solution to achieve the regulation of the proton exchange membrane microstructure and the electrochemical properties of the proton exchange membrane.

[0004] However, due to differences in physical and chemical structures, the structure and properties of the surface of polymer materials are usually very different from those inside the material. The morphology, structure and composition of the atoms or atomic groups near the outermost layer of the material surface play a dominant role in the surface properties of the material, and the surface properties directly affect the performance of the entire material in practical applications. For thin film materials, due to their relatively large specific surface area, the surface properties have a more important impact on their overall performance. In fuel cells, the surface of the proton exchange membrane, as the area in direct contact with the catalyst layer, water, and reaction gas, plays an important role in the proton conduction, water transport and other properties of the proton exchange membrane. Therefore, in view of the differences in the surface and internal properties of the proton exchange membrane, it is of great significance to reduce or eliminate the obstacles of the surface structure to proton conduction and water transport, and promote the formation of a uniform surface, which is of great significance for improving the proton conductivity of the proton exchange membrane and reducing the hydrogen permeability. Summary of the invention

[0005] The present application provides a proton exchange membrane and a preparation method thereof, aiming to solve the problem of obstructed proton conduction and water transport caused by the surface structure of the existing proton exchange membrane, and the problem of high hydrogen permeability of the proton exchange membrane caused by poor surface uniformity of the proton exchange membrane.

[0006] In a first aspect, the present application provides a method for preparing a proton exchange membrane, comprising the following steps: contacting a proton exchange membrane body with a treatment solvent at a temperature of 80-160° C. to obtain the proton exchange membrane.

[0007] The preparation method of the proton exchange membrane described in the present application adopts solvent high-temperature steam surface treatment technology to improve the surface structure and properties of the proton exchange membrane body, reduce or eliminate the obstruction of the surface structure to proton conduction and water transport, and enhance the water transport and proton conduction capabilities of the proton exchange membrane. At the same time, based on the optimization and adjustment of the surface structure, the formation of a uniform surface is promoted, and the hydrogen permeability of the proton exchange membrane is reduced.

[0008] According to some embodiments of the method for preparing a proton exchange membrane described in the present application, the proton exchange membrane body is contacted with the vapor of a treatment solvent.

[0009] According to some embodiments of the method for preparing a proton exchange membrane described in the present application, the proton exchange membrane body includes a perfluorosulfonic acid resin proton exchange membrane.

[0010] According to some embodiments of the method for preparing a proton exchange membrane described in the present application, the method for preparing a perfluorosulfonic acid resin proton exchange membrane comprises the following steps:

[0011] a. mixing a perfluorosulfonic acid resin and a dispersing solvent to obtain a perfluorosulfonic acid resin solution;

[0012] b. Drying and molding the perfluorosulfonic acid resin solution to obtain a perfluorosulfonic acid resin proton exchange membrane.

[0013] According to some embodiments of the method for preparing a proton exchange membrane described in the present application, the dispersing solvent includes one or more of water, methanol, ethanol, propanol, butanol, octanol, ethylene glycol, glycerol, N,N-dimethylformamide, N-methylpyrrolidone and dimethyl sulfoxide.

[0014] According to some embodiments of the method for preparing a proton exchange membrane described in the present application, the mass ratio of the perfluorosulfonic acid resin to the dispersion solvent is (10-30): (100-200).

[0015] According to some embodiments of the method for preparing a proton exchange membrane described in the present application, the proton exchange equivalent of the perfluorosulfonic acid resin is 700-1200 g / mol.

[0016] According to some embodiments of the method for preparing the proton exchange membrane of the present application, the molecular weight of the perfluorosulfonic acid resin is 5×10 4 -1×10 6 g / mol.

[0017] According to some embodiments of the method for preparing a proton exchange membrane described in the present application, the mixing temperature is 25-80° C., and the mixing time is 1-24 h.

[0018] According to some embodiments of the method for preparing a proton exchange membrane described in the present application, the drying temperature is 60-200° C., and the drying time is 5-40 min.

[0019] According to some embodiments of the method for preparing a proton exchange membrane described in the present application, the contact temperature is 100-140° C., and the contact time is 0.1-28 h, preferably 11-13 h.

[0020] According to some embodiments of the method for preparing a proton exchange membrane described in the present application, the mass ratio of the proton exchange membrane body to the processing solvent is 1:(8-12).

[0021] According to some embodiments of the method for preparing a proton exchange membrane described in the present application, the processing solvent includes one or more of cyclohexanone, ethanolamine, octanol, hexanol, ethylene glycol, glycerol, N,N-dimethylformamide and dimethyl sulfoxide.

[0022] According to some embodiments of the method for preparing a proton exchange membrane described in the present application, the processing solvent includes ethylene glycol and / or octanol.

[0023] According to some embodiments of the method for preparing a proton exchange membrane described in the present application, the processing solvent is a mixture of ethylene glycol and octanol, and more preferably, the volume ratio of the ethylene glycol to the octanol is 1:(0.8-1.2).

[0024] According to some embodiments of the method for preparing a proton exchange membrane described in the present application, the method further comprises washing and drying a product obtained after the proton exchange membrane body and the processing solvent come into contact with each other.

[0025] According to some embodiments of the method for preparing a proton exchange membrane described in the present application, the cleaning includes sequentially cleaning with sulfuric acid and deionized water.

[0026] According to some embodiments of the method for preparing a proton exchange membrane described in the present application, the concentration of the sulfuric acid is 1-2 mol / L, and the cleaning temperature of the deionized water is 70-90°C.

[0027] According to some embodiments of the method for preparing a proton exchange membrane described in the present application, the drying temperature is 70-90° C., and the drying time is 6-10 h.

[0028] The second aspect of the present application provides a proton exchange membrane, which is prepared by the preparation method described in the first aspect of the present application. DETAILED DESCRIPTION

[0030] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0031] The embodiment of the present application provides a method for preparing a proton exchange membrane, comprising the following steps: contacting a proton exchange membrane body with a processing solvent at a temperature of 80-160° C. to obtain the proton exchange membrane.

[0032] The preparation method of the proton exchange membrane described in the present application adopts solvent high-temperature steam surface treatment technology to improve the surface structure and properties of the proton exchange membrane body, reduce or eliminate the obstruction of the surface structure to proton conduction and water transport, and enhance the water transport and proton conduction capabilities of the proton exchange membrane. At the same time, based on the optimization and adjustment of the surface structure, the formation of a uniform surface is promoted, and the hydrogen permeability of the proton exchange membrane is reduced.

[0033] In some embodiments of the present application, the proton exchange membrane body is contacted with the vapor of the process solvent.

[0034] In some embodiments of the present application, the proton exchange membrane includes a perfluorosulfonic acid resin proton exchange membrane.

[0035] In some embodiments of the present application, the method for preparing the perfluorosulfonic acid resin proton exchange membrane comprises the following steps:

[0036] a. mixing a perfluorosulfonic acid resin and a dispersing solvent to obtain a perfluorosulfonic acid resin solution;

[0037] b. Drying and molding the perfluorosulfonic acid resin solution to obtain a perfluorosulfonic acid resin proton exchange membrane. The drying and molding method may be cast drying and molding.

[0038] In some embodiments of the present application, the dispersion solvent includes one or more of water, methanol, ethanol, propanol, butanol, octanol, ethylene glycol, glycerol, N,N-dimethylformamide, N-methylpyrrolidone and dimethyl sulfoxide.

[0039] In some embodiments of the present application, the mass ratio of the perfluorosulfonic acid resin to the dispersing solvent is (10-30):(100-200); for example, 10:100, 10:150, 10:200, 20:100, 20:150, 20:200, 30:100, 30:150, 30:200, etc.

[0040] In some embodiments of the present application, the proton exchange equivalent of the perfluorosulfonic acid resin is 700-1200 g / mol; for example, 700 g / mol, 800 g / mol, 900 g / mol, 1000 g / mol, 1100 g / mol, 1200 g / mol, etc.

[0041] In some embodiments of the present application, the molecular weight of the perfluorosulfonic acid resin is 5×10 4 -1×10 6 g / mol.

[0042] In some embodiments of the present application, the mixing temperature is 25-80°C, for example, 25°C, 30°C, 35°C, 43°C, 48°C, 53°C, 59°C, 63°C, 69°C, 70°C, 76°C, 80°C, etc., and the mixing time is 1-24h, for example, 1h, 3h, 8h, 10h, 16h, 21h, 24h, etc.

[0043] In some embodiments of the present application, the drying temperature is 60-200°C, for example, 60°C, 80°C, 120°C, 160°C, 190°C, 200°C, etc., and the drying time is 5-40min, for example, 5min, 12min, 18min, 23min, 29min, 36min, 40min, etc.

[0044] In some embodiments of the present application, the contact temperature is 100-140°C, such as 100°C, 110°C, 115°C, 120°C, 126°C, 130°C, 132°C, 138°C, 140°C, etc. This temperature is lower than the boiling point of the treatment solvent to ensure that the experiment is carried out under normal pressure conditions, and is higher than the glass transition temperature of the perfluorosulfonic acid resin, which is conducive to the dynamic migration of the hydrophobic fluorocarbon main chain and the hydrophilic sulfonic acid side chain, and the rearrangement of the chain segments increases the uniformity of the surface of the proton exchange membrane, causing changes in the surface structure of the proton exchange membrane and the hydrophilic and hydrophobic properties. The contact time is 0.1-28h, such as 0.1h, 2h, 5h, 8h, 10h, 12h, 16h, 19h, 21h, 24h, 26h, 28h, etc., preferably 11-13h.

[0045] In some embodiments of the present application, the mass ratio of the proton exchange membrane body to the processing solvent is 1:(8-12), for example, 1:8, 1:9, 1:10, 1:12, etc.

[0046] In some embodiments of the present application, the processing solvent includes one or more of cyclohexanone, ethanolamine, octanol, hexanol, ethylene glycol, propylene glycol, N,N-dimethylformamide and dimethyl sulfoxide. The above solvents are selected according to the principle of matching the solubility parameters between the perfluorosulfonic acid polymer and the solvent. The selected solvents are solvents with similar solubility parameters to the main chain and side chain of the perfluorosulfonic acid polymer (as shown in Table 1). The solubility parameters of the main chain and side chain of the perfluorosulfonic acid polymer are 9.7 (cal / cm 3 ) 1 / 2 、17.3(cal / cm 3 ) 1 / 2 .

[0047] Table 1 Solubility parameters and boiling points of solvents

[0048] Solvents <![CDATA[Solubility parameter δ (cal / cm 3 ) 1 / 2 > Boiling point(℃) Cyclohexanone 9.9 155 Octanol 10.3 196 Hexanol 10.7 156 N,N-Dimethylformamide 12.1 153 Dimethyl sulfoxide 12.9 189 Ethylene glycol 16.3 197 Glycerol 16.5 290 Ethanolamine 15.4 170

[0049] In some embodiments of the present application, the processing solvent includes ethylene glycol and / or octanol.

[0050] In some embodiments of the present application, the processing solvent is a mixture of ethylene glycol and octanol, both of which are solvents that are compatible with the main chain and side chain of perfluorosulfonic acid, respectively. The mixed vapor environment is conducive to the joint migration of the main chain and side chain of perfluorosulfonic acid to the surface, thereby weakening the difference in structure and properties between the surface and internal parts of the proton exchange membrane and promoting the formation of a uniform surface. More preferably, the volume ratio of the ethylene glycol to the octanol is 1:(0.8-1.2).

[0051] In some embodiments of the present application, the preparation method further comprises washing and drying the product after the proton exchange membrane body and the processing solvent come into contact with each other.

[0052] In some embodiments of the present application, the cleaning includes sequentially cleaning with sulfuric acid and deionized water. The cleaning can remove the processing solvent remaining on the proton exchange membrane.

[0053] In some embodiments of the present application, the concentration of the sulfuric acid is 1-2 mol / L, and the cleaning temperature of the deionized water is 70-90°C.

[0054] In some embodiments of the present application, the drying temperature is 70-90° C., and the drying time is 6-10 hours.

[0055] An embodiment of the present application also provides a proton exchange membrane, which is prepared by the preparation method described in the first aspect of the present application.

[0056] The technical solution of this application is further explained below in conjunction with specific implementation cases.

[0057] Example 1

[0058] A method for preparing a proton exchange membrane comprises the following steps:

[0059] (1) Preparation of perfluorosulfonic acid resin solution: 15 g of perfluorosulfonic acid resin (EW value 1100, molecular weight 50,000) was weighed and dissolved in 100 mL of ethanol dispersion solvent and stirred at 25°C for 10 h;

[0060] (2) pouring the perfluorosulfonic acid resin solution in step (1) onto a flat substrate and drying it in an oven at 160° C. for 20 min to obtain a proton exchange membrane body;

[0061] (3) Add 20 mL of ethylene glycol treatment solvent to a glass container, and then take 2 g of the proton exchange membrane body obtained in step (2) and put it into the above glass container. Then place the glass container in an oven at a temperature of 140° C. and keep it at this temperature for 12 hours. After the treatment is completed, the proton exchange membrane body is cooled at room temperature, and then cleaned with 1M sulfuric acid solution and 80° C. deionized water in turn, each rinse time is 1 hour, repeated 3 times, and finally dried at 80° C. for 6 hours to obtain the proton exchange membrane.

[0062] Example 2

[0063] The only difference between Example 2 and Example 1 is that the processing solvent used in the preparation method of the proton exchange membrane described in Example 2 is octanol solvent.

[0064] The specific steps are:

[0065] (1) Preparation of perfluorosulfonic acid resin solution: 15 g of perfluorosulfonic acid resin (EW value 1100, molecular weight 50,000) was weighed and dissolved in 100 mL of ethanol dispersion solvent and stirred at 25°C for 10 h;

[0066] (2) pouring the perfluorosulfonic acid resin solution in step (1) onto a flat substrate and drying it in an oven at 160° C. for 20 min to obtain a proton exchange membrane body;

[0067] (3) Add 20 mL of octanol treatment solvent to a glass container, and then take 2 g of the proton exchange membrane body obtained in step (2) and put it into the above glass container. Then place the glass container in an oven at a temperature of 140° C. and keep it at this temperature for 12 hours. After the treatment is completed, the proton exchange membrane body is cooled at room temperature, and then cleaned with 1M sulfuric acid solution and 80° C. deionized water in turn, each rinse time is 1 hour, repeated 3 times, and finally dried at 80° C. for 6 hours to obtain the proton exchange membrane.

[0068] Example 3

[0069] The only difference between Example 3 and Example 1 is that the processing solvent used in the method for preparing the proton exchange membrane in Example 3 is a mixture of ethylene glycol and octanol in a volume ratio of 1:1.

[0070] The specific steps are:

[0071] (1) Preparation of perfluorosulfonic acid resin solution: 15 g of perfluorosulfonic acid resin (EW value 1100, molecular weight 50,000) was weighed and dissolved in 100 mL of ethanol dispersion solvent and stirred at 25°C for 10 h;

[0072] (2) pouring the perfluorosulfonic acid resin solution in step (1) onto a flat substrate and drying it in an oven at 160° C. for 20 min to obtain a proton exchange membrane body;

[0073] (3) Add 20 mL of a mixture of ethylene glycol and octanol in a volume ratio of 1:1 to a glass container, and then take 2 g of the proton exchange membrane body obtained in step (2) and put it into the above glass container. Then place the glass container in an oven at a temperature of 140°C and keep it at this temperature for 12 hours. After the treatment is completed, the proton exchange membrane body is cooled at room temperature, and then cleaned with 1M sulfuric acid solution and 80°C deionized water in turn, each rinse time is 1 hour, repeated 3 times, and finally dried at 80°C for 6 hours to obtain the proton exchange membrane.

[0074] Example 4

[0075] The only difference between Example 4 and Example 3 is that, in the method for preparing the proton exchange membrane described in Example 4, the proton exchange membrane body and the processing solvent are contacted at a temperature of 80°C.

[0076] The specific steps are:

[0077] (1) Preparation of perfluorosulfonic acid resin solution: 15 g of perfluorosulfonic acid resin (EW value 1100, molecular weight 50,000) was weighed and dissolved in 100 mL of ethanol dispersion solvent and stirred at 25°C for 10 h;

[0078] (2) pouring the perfluorosulfonic acid resin solution in step (1) onto a flat substrate and drying it in an oven at 160° C. for 20 min to obtain a proton exchange membrane body;

[0079] (3) Add 20 mL of a mixture of ethylene glycol and octanol in a volume ratio of 1:1 to a glass container, and then take 2 g of the proton exchange membrane body obtained in step (2) and put it into the above glass container. Then place the glass container in an oven at a temperature of 80°C and keep it at this temperature for 12 hours. After the treatment is completed, the proton exchange membrane body is cooled at room temperature, and then cleaned with 1M sulfuric acid solution and 80°C deionized water in turn, each rinse time is 1 hour, repeated 3 times, and finally dried at 80°C for 6 hours to obtain the proton exchange membrane.

[0080] Example 5

[0081] The only difference between Example 5 and Example 3 is that, in the method for preparing the proton exchange membrane described in Example 5, the proton exchange membrane body and the processing solvent are contacted at a temperature of 100°C.

[0082] The specific steps are:

[0083] (1) Preparation of perfluorosulfonic acid resin solution: 15 g of perfluorosulfonic acid resin (EW value 1100, molecular weight 50,000) was weighed and dissolved in 100 mL of ethanol dispersion solvent and stirred at 25°C for 10 h;

[0084] (2) pouring the perfluorosulfonic acid resin solution in step (1) onto a flat substrate and drying it in an oven at 160° C. for 20 min to obtain a proton exchange membrane body;

[0085] (3) Add 20 mL of a mixture of ethylene glycol and octanol in a volume ratio of 1:1 to a glass container, and then take 2 g of the proton exchange membrane body obtained in step (2) and put it into the above glass container. Then place the glass container in an oven at a temperature of 100° C. and keep it at this temperature for 12 hours. After the treatment is completed, the proton exchange membrane body is cooled at room temperature, and then cleaned with 1M sulfuric acid solution and 80° C. deionized water in turn, each rinse lasting 1 hour, repeated 3 times, and finally dried at 80° C. for 6 hours to obtain the proton exchange membrane.

[0086] Example 6

[0087] The only difference between Example 6 and Example 3 is that, in the method for preparing the proton exchange membrane described in Example 6, the proton exchange membrane body and the processing solvent are contacted at a temperature of 120°C.

[0088] The specific steps are:

[0089] (1) Preparation of perfluorosulfonic acid resin solution: 15 g of perfluorosulfonic acid resin (EW value 1100, molecular weight 50,000) was weighed and dissolved in 100 mL of ethanol dispersion solvent and stirred at 25°C for 10 h;

[0090] (2) pouring the perfluorosulfonic acid resin solution in step (1) onto a flat substrate and drying it in an oven at 160° C. for 20 min to obtain a proton exchange membrane body;

[0091] (3) Add 20 mL of a mixture of ethylene glycol and octanol in a volume ratio of 1:1 to a glass container, and then take 2 g of the proton exchange membrane body obtained in step (2) and put it into the above glass container. Then place the glass container in an oven at a temperature of 120° C. and keep it at this temperature for 12 hours. After the treatment is completed, the proton exchange membrane body is cooled at room temperature, and then cleaned with 1M sulfuric acid solution and 80° C. deionized water in turn, each rinse lasting 1 hour, repeated 3 times, and finally dried at 80° C. for 6 hours to obtain the proton exchange membrane.

[0092] Example 7

[0093] The only difference between Example 7 and Example 3 is that, in the method for preparing the proton exchange membrane described in Example 7, the proton exchange membrane body and the processing solvent are contacted at a temperature of 160°C.

[0094] The specific steps are:

[0095] (1) Preparation of perfluorosulfonic acid resin solution: 15 g of perfluorosulfonic acid resin (EW value 1100, molecular weight 50,000) was weighed and dissolved in 100 mL of ethanol dispersion solvent and stirred at 25°C for 10 h;

[0096] (2) pouring the perfluorosulfonic acid resin solution in step (1) onto a flat substrate and drying it in an oven at 160° C. for 20 min to obtain a proton exchange membrane body;

[0097] (3) Add 20 mL of a mixture of ethylene glycol and octanol in a volume ratio of 1:1 to a glass container, and then take 2 g of the proton exchange membrane body obtained in step (2) and put it into the above glass container. Then place the glass container in an oven at a temperature of 160°C and keep it at this temperature for 12 hours. After the treatment is completed, the proton exchange membrane body is cooled at room temperature, and then cleaned with 1M sulfuric acid solution and 80°C deionized water in turn, each rinse time is 1 hour, repeated 3 times, and finally dried at 80°C for 6 hours to obtain the proton exchange membrane.

[0098] Example 8

[0099] The only difference between Example 8 and Example 5 is that in the method for preparing the proton exchange membrane described in Example 8, the proton exchange membrane body is contacted with the ethylene glycol treatment solvent and the octanol treatment solvent in sequence.

[0100] The specific steps are:

[0101] (1) Preparation of perfluorosulfonic acid resin solution: 15 g of perfluorosulfonic acid resin (EW value 1100, molecular weight 50,000) was weighed and dissolved in 100 mL of ethanol dispersion solvent and stirred at 25°C for 10 h;

[0102] (2) pouring the perfluorosulfonic acid resin solution in step (1) onto a flat substrate and drying it in an oven at 160° C. for 20 min to obtain a proton exchange membrane body;

[0103] (3) Add 20 mL of ethylene glycol treatment solvent and 20 mL of octanol treatment solvent to two glass containers respectively, take 2 g of the proton exchange membrane body obtained in step (2) and put it into the glass container containing ethylene glycol treatment solvent, then place the glass container in an oven at a temperature of 100° C. and keep it at this temperature for 12 hours. After the treatment is completed, the proton exchange membrane body is placed at room temperature for cooling. Then, the cooled proton exchange membrane body is placed in a glass container containing octanol treatment solvent, and then the glass container is placed in an oven at a temperature of 100° C. and kept at this temperature for 12 hours. After the treatment is completed, 1M sulfuric acid solution and 80° C. deionized water are used for cleaning in turn, each rinsing time is 1 hour, repeated 3 times, and finally dried at 80° C. for 6 hours to obtain the proton exchange membrane.

[0104] Example 9

[0105] The only difference between Example 9 and Example 5 is that in the method for preparing the proton exchange membrane described in Example 9, the proton exchange membrane body is contacted with an octanol treatment solvent and an ethylene glycol treatment solvent in sequence.

[0106] The specific steps are:

[0107] (1) Preparation of perfluorosulfonic acid resin solution: 15 g of perfluorosulfonic acid resin (EW value 1100, molecular weight 50,000) was weighed and dissolved in 100 mL of ethanol dispersion solvent and stirred at 25°C for 10 h;

[0108] (2) pouring the perfluorosulfonic acid resin solution in step (1) onto a flat substrate and drying it in an oven at 160° C. for 20 min to obtain a proton exchange membrane body;

[0109] (3) Add 20 mL of octanol treatment solvent and 20 mL of ethylene glycol treatment solvent to two glass containers respectively, take 2 g of the proton exchange membrane body obtained in step (2) and put it into the glass container containing octanol treatment solvent, then place the glass container in an oven at a temperature of 100° C. and keep it at this temperature for 12 hours. After the treatment is completed, the proton exchange membrane body is placed at room temperature to cool. Then, the cooled proton exchange membrane body is placed in a glass container containing ethylene glycol treatment solvent, and then the glass container is placed in an oven at a temperature of 100° C. and kept at this temperature for 12 hours. After the treatment is completed, 1M sulfuric acid solution and 80° C. deionized water are used for cleaning in turn, each rinsing time is 1 hour, repeated 3 times, and finally dried at 80° C. for 6 hours to obtain the proton exchange membrane.

[0110] Comparative Example 1

[0111] The difference between Comparative Example 1 and Example 1 is that the proton exchange membrane body is not treated with a treatment solvent.

[0112] The specific steps are:

[0113] (1) Preparation of perfluorosulfonic acid resin solution: 15 g of perfluorosulfonic acid resin (EW value 1100, molecular weight 50,000) was weighed and dissolved in 100 mL of ethanol dispersion solvent and stirred at 25°C for 10 h;

[0114] (2) The perfluorosulfonic acid resin solution in step (1) is poured onto a flat substrate and dried in an oven at 160° C. for 20 min to obtain a proton exchange membrane body.

[0115] Performance study of the proton exchange membranes prepared in Examples 1-9 and Comparative Example 1 of the present application:

[0116] 1. The test results of the contact angle and water absorption rate of the proton exchange membranes prepared in Examples 1-9 of the present application and Comparative Example 1 are shown in Table 2.

[0117] Table 2

[0118]

[0119]

[0120] Note: The contact angle test method described in this application is: The static contact angle of the proton exchange membrane is measured using a contact angle meter, using the hanging drop method at room temperature, with a water drop volume of 4 μL. The sample size is 50 mm × 20 mm, and 5 points are taken for each sample for testing, and the average value is taken as the contact angle value.

[0121] The test method of the absorption rate described in the present application is as follows: the water absorption rate of the proton exchange membrane is measured by a dynamic moisture adsorption instrument, the sample mass is 30 μg, the humidity measurement range is 0-97% RH, and the water absorption rate value at 80% humidity is taken. Each sample is tested 3 times, and the average value is taken as the water absorption rate value.

[0122] It can be seen from Table 2 that the use of solvent high-temperature steam surface treatment of proton exchange membranes can reduce the contact angle of proton exchange membranes and increase the water absorption rate of proton exchange membranes. This is because under the conditions of high-temperature steam atmosphere, the hydrophobic fluorocarbon main chain and the hydrophilic sulfonic acid side chain undergo dynamic migration, the chain segments are rearranged and the uniformity is increased, resulting in changes in the surface structure of the proton exchange membrane and the hydrophilic and hydrophobic properties.

[0123] Comparative Examples 1-3 and Comparative Example 1 show that the contact angle of the proton exchange membrane treated with a 1:1 mixed solvent of ethylene glycol and octanol decreases and the degree of increase in water absorption is more significant. Comparative Examples 4-7 and Comparative Example 1 show that when the treatment temperature is 100°C, the contact angle of the proton exchange membrane decreases and the degree of increase in water absorption is most significant. Comparative Examples 8 and 9 show that when multiple treatment steps are used, the order of solvent treatment has a greater influence on the degree of change in contact angle and water absorption. When octanol is used first and ethylene glycol is used later, the contact angle of the proton exchange membrane decreases and the degree of increase in water absorption is more significant. The above phenomenon is related to their respective solubility parameters. When the solubility parameter of the treatment solvent is similar to that of the fluorocarbon main chain, the fluorocarbon main chain tends to migrate dynamically to the surface; when the solubility parameter of the treatment solvent is similar to that of the sulfonic acid side chain, the sulfonic acid side chain tends to migrate dynamically to the surface; when the solvents of the two solubility parameters are mixed, it is manifested as the result of competitive migration of the fluorocarbon main chain and the sulfonic acid side chain, which is also related to the high or low treatment temperature.

[0124] 2. The internal resistance test results of the proton exchange membranes prepared in Examples 1-9 of the present application and Comparative Example 1 are shown in Table 3.

[0125] Table 3

[0126]

[0127]

[0128] Note: The test method of internal resistance described in this application is: the internal resistance of the proton exchange membrane is measured by a penetration conductivity tester, the sample size is 30mm×10mm, and the internal resistance value at 30% humidity is taken. Each sample is tested 3 times, and the average value is taken as the internal resistance value.

[0129] It can be seen from Table 3 that the internal resistance of the proton exchange membrane can be reduced by using solvent high-temperature steam to treat the proton exchange membrane surface, which is consistent with the change law of the contact angle and water absorption rate of the proton exchange membrane. By optimizing the surface structure and performance of the proton exchange membrane, eliminating or weakening the obstruction of the surface structure to proton conduction and water transport, the internal resistance of the proton exchange membrane can be effectively reduced, which is conducive to the improvement of proton conduction capacity.

[0130] 3. The test results of hydrogen permeation current density of the proton exchange membranes prepared in Examples 1-9 of the present application and Comparative Example 1 are shown in Table 4.

[0131] Table 4

[0132] project <![CDATA[Hydrogen permeation current density (mA / cm 2 )]]> Example 1 3.2 Example 2 3.9 Example 3 2.1 Example 4 2.6 Example 5 1.7 Example 6 1.9 Example 7 2.7 Example 8 4.3 Example 9 3.0 Comparative Example 1 5.1

[0133] Note: The test method for hydrogen permeation current density described in this application is as follows: The hydrogen permeation current density of the proton exchange membrane is measured using a fuel cell test bench, the prepared membrane electrode size is 50mm×50mm, the applied scanning voltage range is 0V~0.5V (vs RHE), and the scanning speed is 2mV / s. The test is repeated twice, and the hydrogen permeation current density at 0.4V is taken.

[0134] It can be seen from Table 3 that the use of solvent high-temperature steam surface treatment of proton exchange membranes can reduce the hydrogen permeation current density of proton exchange membranes, which is related to the changes in the surface structure and performance of proton exchange membranes. Under high-temperature steam atmosphere conditions, the molecular segments undergo dynamic migration and rearrangement, and the uniformity of the proton exchange membrane surface increases.

[0135] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.

Claims

1. A method for preparing a proton exchange membrane, characterized in that: The following steps are involved: contacting the proton exchange membrane body with a treatment solvent at a temperature of 80-160° C. to obtain the proton exchange membrane; Preferably, the proton exchange membrane body is contacted with the vapor of the process solvent.

2. The method for preparing a proton exchange membrane according to claim 1, characterized in that: The proton exchange membrane body comprises a perfluorosulfonic acid resin proton exchange membrane; Preferably, the method for preparing the perfluorosulfonic acid resin proton exchange membrane comprises the following steps: a. mixing a perfluorosulfonic acid resin and a dispersing solvent to obtain a perfluorosulfonic acid resin solution; b. Drying and molding the perfluorosulfonic acid resin solution to obtain a perfluorosulfonic acid resin proton exchange membrane.

3. The method for preparing a proton exchange membrane according to claim 2, characterized in that: The dispersing solvent includes one or more of water, methanol, ethanol, propanol, butanol, octanol, ethylene glycol, glycerol, N,N-dimethylformamide, N-methylpyrrolidone and dimethyl sulfoxide; and / or, the mass ratio of the perfluorosulfonic acid resin to the dispersing solvent is (10-30): (100-200); preferably, the proton exchange equivalent of the perfluorosulfonic acid resin is 700-1200 g / mol; more preferably, the molecular weight of the perfluorosulfonic acid resin is 5×10 4 -1×10 6 g / mol; And / or, the mixing temperature is 25-80°C, and the mixing time is 1-24h; And / or, the drying temperature is 60-200° C., and the drying time is 5-40 min.

4. The method for preparing a proton exchange membrane according to claim 1, characterized in that: The contacting temperature is 100-140° C., and the contacting time is 0.1-28 h, preferably 11-13 h.

5. The method for preparing a proton exchange membrane according to claim 1, characterized in that: The mass ratio of the proton exchange membrane body to the treatment solvent is 1:(8-12).

6. The method for preparing a proton exchange membrane according to claim 1, characterized in that: The processing solvent includes one or more of cyclohexanone, ethanolamine, octanol, hexanol, ethylene glycol, glycerol, N,N-dimethylformamide and dimethyl sulfoxide.

7. The method for preparing a proton exchange membrane according to claim 1, characterized in that: The processing solvent includes ethylene glycol and / or octanol.

8. The method for preparing a proton exchange membrane according to claim 1, characterized in that: The processing solvent is a mixture of ethylene glycol and octanol. More preferably, the volume ratio of the ethylene glycol to the octanol is 1:(0.8-1.2).

9. The method for preparing a proton exchange membrane according to claim 1, characterized in that: The preparation method further comprises washing and drying the product after the proton exchange membrane body and the processing solvent are in contact; Preferably, the cleaning comprises cleaning with sulfuric acid and deionized water in sequence; Preferably, the concentration of the sulfuric acid is 1-2 mol / L, and the cleaning temperature of the deionized water is 70-90°C; Preferably, the drying temperature is 70-90° C., and the drying time is 6-10 h.

10. A proton exchange membrane, characterized in that: The proton exchange membrane is prepared by the preparation method according to any one of claims 1 to 9.

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