A proton exchange membrane and its preparation method and application

Abstract

The present invention discloses a proton exchange membrane and a preparation method and application thereof. The proton exchange membrane comprises a coating layer, wherein the coating layer contains hydrated nano-cerium oxide. The present invention adopts hydrated nano-cerium oxide as a free radical quencher, which is added to a coating liquid in the form of hydrated nano-cerium oxide sol and can be well and evenly dispersed; its surface is rich in hydroxyl groups, which can have the effect of water retention and humidification on the proton exchange membrane; the smaller particle size will not bring additional defects to the proton exchange membrane; the prepared proton exchange membrane has excellent durability.

Description

Technical Field

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

[0002] Fuel cells are a clean energy technology that can alleviate energy and environmental problems. Proton exchange membrane fuel cells are an important type of fuel cell that has been used in new energy vehicles; the proton exchange membrane is its key component, which plays a role in transferring protons, blocking cathode and anode materials, and blocking electrons.

[0003] In the actual operation of proton exchange membrane fuel cells, there will be more or less reaction gas penetration, which causes hydrogen and oxygen to come into direct contact, react to generate H2O2, and then react with impurity ions such as Fe in the fuel cell. 2+ The reaction produces free radicals HO·. The carboxylic acid groups on the side chains and end chains of the perfluorosulfonic acid membrane are easily attacked by free radicals. As a result, the long polymer chains of the membrane are gradually corroded and degraded, accelerating the corrosion of the proton exchange membrane and making the membrane thinner and thinner.

[0004] In order to improve the durability of the proton exchange membrane, a free radical quencher is generally added to it. Cerium dioxide is widely used in proton exchange membranes due to its super strong free radical quenching performance. However, ordinary ceria is difficult to disperse evenly in the proton exchange membrane coating liquid; and the addition of additional ceria reduces the proportion of perfluorosulfonic acid resin in the proton exchange membrane, which will affect the performance of the proton exchange membrane. Summary of the invention

[0005] In order to improve the above technical problems, the study found that in addition to the difficulty of uniformly dispersing cerium dioxide particles in the coating liquid of the proton exchange membrane, during the continuous production coating process, the cerium dioxide particles in the coating liquid in the silo will settle, which will easily cause the cerium dioxide content in the same batch of proton exchange membranes (PEM) to be different, and the product quality stability cannot be guaranteed; in addition, ordinary cerium dioxide particles are non-hydrophilic inorganic substances, and when doped into perfluorosulfonic acid PEM, they tend to enter the organic phase of perfluorosulfonic acid resin, reducing the mechanical properties of PEM. Based on this, the present invention proposes to add hydrated nano-cerium oxide as a free radical quencher to the proton exchange membrane. The surface of hydrated nano-cerium oxide is rich in hydroxyl groups, which is hydrophilic and can improve the water retention performance of the proton exchange membrane; in addition, the polarization performance and durability of the proton exchange membrane are also significantly improved compared with the proton exchange membrane made of nano-cerium oxide particles.

[0006] The technical solution of the present invention is as follows:

[0007] A proton exchange membrane comprises a coating layer containing hydrated nano cerium oxide.

[0008] According to the present invention, the surface of the hydrated nano-cerium oxide is rich in hydroxyl groups.

[0009] According to the present invention, the average particle size of the hydrated nano-cerium oxide is 3nm to 15nm, for example, 3nm to 8nm, and also for example, 3nm to 5nm; illustratively, it is 3nm, 3.5nm, 4nm, 4.5nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 14nm or 15nm.

[0010] According to the present invention, the coating layer further contains a resin, and specifically, the resin contains ionic phase cavities. The coating layer of the present invention refers to a coating layer that has been formed into a film.

[0011] According to the present invention, in the coating layer, the resin exists in the form of a continuous phase, and the hydrated nano-cerium oxide is mainly distributed in the ionic phase cavity of the resin.

[0012] In the present invention, the surface of the hydrated nano-cerium oxide is rich in hydroxyl groups, which are hydrophilic and tend to enter the ionic phase cavity of the resin in the proton exchange membrane. Under the condition of not affecting the continuity of the resin (i.e., not reducing the mechanical properties of the proton exchange membrane), the water retention performance of the proton exchange membrane can be improved.

[0013] According to the present invention, the resin is, for example, a perfluorosulfonic acid resin.

[0014] According to the present invention, in the coating layer, the mass ratio of cerium oxide in the hydrated nano-cerium oxide to the resin is (0.01-5.0):100; for example, 0.01:100, 0.05:100, 0.1:100, 1.0:100, 2.0:100, 3.0:100, 4.0:100, 5.0:100.

[0015] According to the present invention, the proton exchange membrane comprises the above-mentioned coating layer and reinforcement layer in sequence.

[0016] According to the present invention, the reinforcement layer further includes the coating layer mentioned above, that is, the proton exchange membrane includes the coating layer, the reinforcement layer and the coating layer mentioned above in sequence.

[0017] According to the present invention, the reinforcement layer is a polytetrafluoroethylene membrane; preferably a porous polytetrafluoroethylene membrane.

[0018] The invention also provides a coating liquid for a proton exchange membrane, wherein the coating liquid contains a resin, a solvent and hydrated nano cerium oxide.

[0019] According to the present invention, the surface of the hydrated nano-cerium oxide is rich in hydroxyl groups.

[0020] According to the present invention, in the coating liquid, the hydrated nano-cerium oxide exists in the form of sol. Specifically, the coating liquid contains hydrated nano-cerium oxide sol.

[0021] According to the present invention, the resin is selected from perfluorosulfonic acid resin.

[0022] According to the present invention, the solid content of the resin in the coating solution for proton exchange membrane is 5-30wt%, exemplarily 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%.

[0023] According to the present invention, the average particle size of the hydrated nano-cerium oxide is 3nm to 15nm, for example, 3nm to 8nm, and also for example, 3nm to 5nm; illustratively, it is 3nm, 3.5nm, 4nm, 4.5nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 14nm or 15nm.

[0024] According to the present invention, the mass ratio of cerium oxide to resin in the hydrated nano-cerium oxide is (0.01-5.0):100; for example, 0.01:100, 0.05:100, 0.1:100, 1.0:100, 2.0:100, 3.0:100, 4.0:100 or 5.0:100.

[0025] According to the present invention, the solvent is alcohol, water or a mixed solvent of alcohol and water. Specifically, the alcohol can be at least one of ethanol, n-propanol and isopropanol.

[0026] According to the present invention, the solvent in the hydrated nano-cerium oxide sol is alcohol, water or a mixed solvent of alcohol and water. Specifically, the alcohol can be at least one of ethanol, n-propanol and isopropanol.

[0027] According to the present invention, the mass ratio of cerium oxide to solvent in the hydrated nano-cerium oxide sol is 1:(1-50), illustratively 1:1, 1:5, 1:9, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45 or 1:50.

[0028] The present invention also provides a method for preparing the coating liquid for proton exchange membrane, which comprises: mixing resin, hydrated nano-cerium oxide and solvent to obtain the coating liquid for proton exchange membrane.

[0029] According to the present invention, the solvent is at least one of alcohol and water, and the alcohol can be at least one of ethanol, n-propanol and isopropanol. When the solvent is a mixture of alcohol and water, the mass ratio of alcohol is 20-80%.

[0030] According to the present invention, the hydrated nano-cerium oxide is added in the form of hydrated nano-cerium oxide sol. Specifically, the solvent in the hydrated nano-cerium oxide sol is alcohol, water or a mixed solvent of alcohol and water. Specifically, the alcohol can be at least one of ethanol, n-propanol and isopropanol.

[0031] According to the present invention, the resin can be added in the form of a resin dispersion, which is obtained by dispersing the resin in a mixed solvent. Specifically, the mixed solvent is an alcohol-water system, for example, a mixed solvent formed by mixing n-propanol, ethanol and water, such as Nafion D2020CS. In the dispersion, the solid content of the resin is 5-30wt%, exemplarily 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%.

[0032] The hydrated nano-cerium oxide and the hydrated nano-cerium oxide sol described in the present invention are prior art products and are prepared by methods known in the art.

[0033] The present invention also provides a method for preparing the above-mentioned proton exchange membrane, the method comprising the following steps:

[0034] (1) coating a layer of the proton exchange membrane coating liquid on a base membrane to form a first liquid film; and drying the liquid film to obtain the proton exchange membrane.

[0035] According to the present invention, the method specifically comprises the following steps:

[0036] (1a) coating a layer of the proton exchange membrane coating liquid on a base membrane to form a first liquid membrane;

[0037] (2) spreading the reinforcement layer on the first liquid film;

[0038] (3) Drying to obtain the proton exchange membrane.

[0039] According to the present invention, the method specifically comprises the following steps:

[0040] (1a) coating a layer of the proton exchange membrane coating liquid on a base membrane to form a first liquid membrane;

[0041] (2) spreading the reinforcement layer on the first liquid film;

[0042] (3a) coating another layer of the proton exchange membrane coating liquid on the reinforcement layer to form a second liquid membrane;

[0043] (4) Drying the wet membrane prepared in step (3a) to obtain the proton exchange membrane.

[0044] According to the present invention, the drying process in step (1), step (3) and step (4) is: first drying at 60-110°C for 5-20 minutes; then annealing and drying at 120-180°C for 1-20 minutes.

[0045] According to the present invention, the reinforcement layer is a polytetrafluoroethylene membrane, preferably a porous polytetrafluoroethylene membrane.

[0046] Beneficial Effects of the Invention

[0047] (1) Conventional cerium oxide has no other function in the proton exchange membrane except for the free radical quenching function; cerium oxide occupies a certain volume in the proton exchange membrane, reduces the proportion of perfluorosulfonic acid resin, and reduces the proton conduction performance of the proton exchange membrane. The present invention uses hydrated nano cerium oxide with rich surface hydroxyl groups as a free radical quencher. The addition of additional hydroxyl groups makes it hydrophilic and tends to enter the ionic phase cavity of perfluorosulfonic acid resin in the proton exchange membrane. Under the condition of not affecting the continuity of perfluorosulfonic acid resin (i.e., not reducing the mechanical properties of the proton exchange membrane), the water retention performance of the proton exchange membrane can be improved, thereby improving its proton conduction performance.

[0048] (2) Cerium oxide is a non-hydrophilic substance and tends to exist in the organic phase of perfluorosulfonic acid resin in the proton exchange membrane, reducing the continuity of the perfluorosulfonic acid resin, thereby reducing the mechanical properties of the proton exchange membrane. The hydrated nano-cerium oxide of the present invention is a hydrophilic substance and exists in the ionic phase pores of the network cluster structure formed by the perfluorosulfonic acid resin in the proton exchange membrane, which does not affect the continuity of the perfluorosulfonic acid resin and the mechanical properties of the proton exchange membrane. Furthermore, the hydroxyl radicals that cause the degradation of the perfluorosulfonic acid resin use water as a carrier, and the hydrated nano-cerium oxide in the hydrophilic ionic phase is more likely to contact the hydroxyl radicals and quench them, and the quenching efficiency is high.

[0049] (3) The hydrated nano-cerium oxide used in the present invention is sol-state cerium oxide of 3-15 nm. Due to its small particle size, the area provided per unit mass is large and the free radical quenching performance is strong; and the small particle size of cerium oxide has little effect on the proton exchange membrane and will not cause additional defects to the proton exchange membrane.

[0050] (4) Cerium oxide has the property of quenching free radicals, but conventional cerium oxide is in a granular form and is difficult to be evenly dispersed in the coating liquid of the proton exchange membrane; and in the continuous membrane-making process, the cerium oxide particles in the coating liquid are easy to settle, resulting in uneven distribution of the free radical quencher in the proton exchange membrane. The present invention directly adds hydrated nano-cerium oxide to the coating liquid for the proton exchange membrane, and in particular, adds it to the coating liquid for the proton exchange membrane in the form of hydrated nano-cerium oxide sol. The hydrated nano-cerium oxide sol itself is a colloidal form in which nano-cerium oxide is evenly dispersed. The dispersion obtained by adding the hydrated nano-cerium oxide sol to the coating liquid is still in the form of nano-cerium oxide colloid evenly dispersed in the coating liquid, that is, a coating liquid in which the free radical quencher is evenly dispersed can be obtained. After the proton exchange membrane is made, the free radical quencher can be evenly dispersed in the proton exchange membrane.

[0051] In summary, the present invention adopts hydrated nano-cerium oxide as a free radical quencher, which is added to the coating liquid in the form of a sol and can be well and evenly dispersed; its surface is rich in hydroxyl groups, which can have the effect of retaining water and increasing humidity for the proton exchange membrane; and the smaller particle size will not bring additional defects to the proton exchange membrane. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 These are the polarization curves of the proton exchange membranes in Comparative Example 1 and Examples 1-3.

[0053] Figure 2 It is the particle size distribution diagram of hydrated nano-cerium oxide sol. DETAILED DESCRIPTION

[0054] The technical scheme of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0055] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0056] Comparative Example 1

[0057] Preparation of proton exchange membrane coating solution:

[0058] 180 g of Nafion D2020CS resin dispersion with a solid content of 20 wt % was weighed, and 20 g of isopropanol was added thereto; mechanical stirring was performed for 30 min, and ultrasonic treatment was performed for 30 min to obtain a coating liquid for a proton exchange membrane with a solid content of 18 wt %.

[0059] Preparation of proton exchange membrane:

[0060] Use the above coating liquid to coat a 60 μm proton exchange membrane coating liquid on the base film (polyimide membrane); composite a 8 μm thick porous polytetrafluoroethylene membrane thereon; then coat a 60 μm proton exchange membrane coating liquid on the porous polytetrafluoroethylene membrane; send the wet membrane to a blast drying oven, dry it at 90°C for 10 minutes to obtain a dry membrane; send the dry membrane to a blast drying oven, heat treat it at 140°C for 10 minutes to obtain a proton exchange membrane.

[0061] Comparative Example 2

[0062] Preparation of proton exchange membrane coating solution:

[0063] Weigh 180 g of Nafion D2020CS resin dispersion with a solid content of 20 wt %, add 20 g of isopropanol and 50 mg of nano-cerium oxide (average particle size of 20-40 nm) thereto; mechanically stir for 30 min and ultrasonically treat for 120 min to obtain a coating liquid for proton exchange membrane with a solid content of 18 wt %.

[0064] Preparation of proton exchange membrane:

[0065] Use the above coating liquid to coat a 60 μm proton exchange membrane coating liquid on the base film (polyimide membrane); composite a 8 μm thick porous polytetrafluoroethylene membrane thereon; then coat a 60 μm proton exchange membrane coating liquid on the porous polytetrafluoroethylene membrane; send the wet membrane to a blast drying oven, dry it at 90°C for 10 minutes to obtain a dry membrane; send the dry membrane to a blast drying oven, heat treat it at 140°C for 10 minutes to obtain a proton exchange membrane.

[0066] Example 1

[0067] The hydrated nano-cerium oxide sol used in the present invention is a commercially available product and is prepared by a method known in the prior art.

[0068] The particle size distribution of hydrated nano-cerium oxide sol was measured by a nano-particle size analyzer. Figure 2 shown; from Figure 2 It can be seen that the particle size of hydrated nano-cerium oxide (sol) is 3.883 nm.

[0069] Preparation of proton exchange membrane coating solution:

[0070] Weigh 180 g of Nafion D2020CS resin dispersion with a solid content of 20 wt%, add 18 g of isopropanol thereto, stir mechanically for 30 min, and treat ultrasonically for 30 min to obtain a coating solution with a solid content of 18 wt%. Add 2.0 g of hydrated nano-cerium oxide sol to the coating solution, stir mechanically for 30 min, and treat ultrasonically for 30 min to obtain a coating solution for coating a proton exchange membrane.

[0071] The preparation method of the proton exchange membrane is the same as that of Comparative Example 1.

[0072] Example 2

[0073] The difference between Example 2 and Example 1 is that in the preparation of the proton exchange membrane coating liquid, "add 18 g of isopropanol thereto" is replaced by "add 16 g of isopropanol thereto"; and "add 2.0 g of hydrated nano-cerium oxide sol to the coating liquid" is replaced by "add 4.0 g of hydrated nano-cerium oxide sol to the coating liquid".

[0074] Example 3

[0075] The difference between Example 3 and Example 1 is that, in the preparation of the proton exchange membrane coating liquid, "add 18 g of isopropanol thereto" is replaced by "add 12 g of isopropanol thereto"; and "add 2.0 g of hydrated nano-cerium oxide sol to the coating liquid" is replaced by "add 8.0 g of hydrated nano-cerium oxide sol to the coating liquid".

[0076] Test Case

[0077] The proton exchange membranes prepared in Examples 1-3 and Comparative Examples 1-2 were tested for proton conductivity, polarization performance, and fluoride ion concentration. The specific test methods are as follows:

[0078] Proton conductivity detection:

[0079] The proton exchange membranes in Examples 1-3 and Comparative Examples 1-2 were placed in a constant temperature and humidity chamber at 25°C and 50% RH for 12 hours, and then taken out for proton conductivity testing. Proton conductivity testing was performed using a four-electrode method under the following conditions: 85°C, 50% RH, a perturbation voltage of 100 mV, and a frequency of 1-10 5 Hz, the size of the proton exchange membrane used for detection is 1 cm×4.5 cm, and the proton conductivity data of the obtained proton exchange membrane are shown in Table 1.

[0080] Polarization performance test:

[0081] Using an ultrasonic sprayer, Pt / C catalyst was sprayed on both sides of the proton exchange membrane in Example 1-3 and Comparative Example 1-2, so that the Pt loading on the anode side of the proton exchange membrane was 0.2 mg / cm 2 , the cathode Pt loading is 0.4 mg / cm 2 , making CCM. CCM is assembled into a single cell, and the test conditions are as follows:

[0082] - Fuel: 99.999% pure H2, stoichiometric ratio 1.2, RH 30%;

[0083] ——Oxidant: Standard air prepared from 99.999% pure nitrogen and high-purity oxygen, with an oxygen content of 21%. The stoichiometric ratio is 2.5, RH 100%;

[0084] ——Battery temperature: 80℃;

[0085] ——Outlet back pressure: gauge pressure 0MPa.

[0086] The measured polarization curve is as follows Figure 1 As shown, Figure 1 The right picture is a partial enlargement of the left picture.

[0087] Fenton experiment method:

[0088] Take 5 cm×5 cm of the proton exchange membranes of Example 1-3 and Comparative Example 1-2, put them into 50 ml of Fenton reagent (30% hydrogen peroxide containing 20 ppm FeSO4), stir and reflux at 80°C for 4 hours, take out the Fenton reagent, and detect the fluoride ion concentration therein; add 50 ml of new Fenton reagent, stir and reflux at 80°C for 4 hours, and repeat the above detection. The fluoride ion concentration in the Fenton reagent is shown in Table 2.

[0089] Table 1 Proton conductivity of proton exchange membranes of Comparative Examples 1-2 and Examples 1-3

[0090]

[0091] From Table 1 and Figure 1 It can be seen that the proton conductivity of the proton exchange membranes prepared in Comparative Examples 1-2 and Examples 1-3 is basically the same, and the addition of hydrated nano-cerium oxide (sol) has no effect on the proton conductivity of the proton exchange membrane; while the proton conductivity of the PEM with the addition of 20-40nm nano-cerium oxide is significantly reduced; this is mainly due to the smaller average particle size of hydrated nano-cerium oxide (sol) (3.883nm, such as Figure 2 The addition of hydrated nano-cerium oxide (sol) introduced a considerable number of hydroxyl groups, improved the water retention of the membrane, and significantly improved the polarization performance of the proton exchange membrane at 80℃RH30% (as shown in Figure 2). Figure 1 shown).

[0092] Table 2 Fluoride ion concentration in proton exchange membranes of Comparative Examples 1-2 and Examples 1-3

[0093]

[0094] As can be seen from Table 2, the fluoride ion concentration of the proton exchange membrane prepared in Comparative Examples 1-2 is much higher than that of the PEM prepared in Examples 1-3 (as shown in Table 2). The addition of hydrated nano-cerium oxide (sol) significantly improves the stability of the proton exchange membrane without affecting other properties of the proton exchange membrane, and reduces the degradation rate of the proton exchange membrane.

[0095] The above is an exemplary description of the embodiments of the present invention. However, the protection scope of the present invention is not limited to the above embodiments. Any modification, equivalent substitution, improvement, etc. made by those skilled in the art within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A proton exchange membrane, characterized in that: The proton exchange membrane comprises a coating layer, wherein the coating layer contains hydrated nano-cerium oxide; The coating layer also contains a resin, which exists in a continuous phase and contains ionic phase cavities; In the coating layer, the hydrated nano-cerium oxide is mainly distributed in the ionic phase cavity of the resin; The average particle size of the hydrated nano-cerium oxide is 3nm to 15nm; The resin is a perfluorosulfonic acid resin; The mass ratio of the cerium oxide in the hydrated nano-cerium oxide to the resin is (0.01-5.0):

100.

2. The proton exchange membrane according to claim 1, characterized in that The proton exchange membrane comprises a coating layer and a reinforcement layer in sequence.

3. The proton exchange membrane according to claim 2, characterized in that The reinforcing layer further includes a coating layer outside the reinforcing layer, that is, the proton exchange membrane includes the coating layer, the reinforcing layer and the coating layer in sequence.

4. The proton exchange membrane according to claim 3, characterized in that The reinforcement layer is a polytetrafluoroethylene film.

5. A coating liquid for a proton exchange membrane according to any one of claims 1 to 4, characterized in that: The coating layer is prepared by the coating liquid; the coating liquid contains resin, solvent and hydrated nano cerium oxide; In the coating liquid, the hydrated nano-cerium oxide exists in the form of sol, that is, the coating liquid contains hydrated nano-cerium oxide sol.

6. The coating liquid for proton exchange membrane according to claim 5, characterized in that: The solid content of the resin in the coating liquid for proton exchange membrane is 5-30wt%.

7. The coating liquid for proton exchange membrane according to claim 5, characterized in that: The mass ratio of cerium oxide to resin in the hydrated nano-cerium oxide is (0.05-2.0):

100.

8. The coating liquid for proton exchange membrane according to claim 5, characterized in that: The mass ratio of cerium oxide to solvent in the hydrated nano-cerium oxide sol is 1:(1-15).

9. The method for preparing a coating liquid for a proton exchange membrane according to any one of claims 5 to 8, characterized in that: The preparation method comprises the following steps: mixing resin, hydrated nano-cerium oxide and solvent to obtain the coating liquid for the proton exchange membrane; Wherein, the hydrated nano-cerium oxide is introduced in the form of hydrated nano-cerium oxide sol.

10. The preparation method according to claim 9, characterized in that: The resin is added in the form of a resin dispersion.

11. The preparation method according to claim 10, characterized in that: In the resin dispersion, the solid content of the resin is 5-30wt%.

12. The preparation method according to claim 9, characterized in that: The solvent is at least one of alcohol and water.

13. The preparation method according to claim 12, characterized in that: The alcohol is at least one of ethanol, n-propanol and isopropanol.

14. The method for preparing a proton exchange membrane according to any one of claims 1 to 4, characterized in that: The method comprises: (1) coating a layer of the coating liquid for proton exchange membrane according to any one of claims 5 to 8 on a base membrane to form a first liquid membrane; (2a) Drying to obtain the proton exchange membrane, wherein the proton exchange membrane contains hydrated nano-cerium oxide.

15. The preparation method according to claim 14, characterized in that: The method specifically comprises the following steps: (1a) coating a layer of the coating liquid for proton exchange membrane according to any one of claims 5 to 8 on a base membrane to form a first liquid membrane; (2) spreading the reinforcement layer on the first liquid film; (3) Drying to obtain the proton exchange membrane, wherein the proton exchange membrane contains hydrated nano-cerium oxide.

16. The preparation method according to claim 15, characterized in that: The method specifically comprises the following steps: (1a) coating a layer of the coating liquid for proton exchange membrane according to any one of claims 5 to 8 on a base membrane to form a first liquid membrane; (2) spreading the reinforcement layer on the first liquid film; (3a) coating a layer of the coating liquid for proton exchange membrane according to any one of claims 5 to 8 on the reinforcement layer to form a second liquid membrane; (4) Drying the wet membrane prepared in step (3a) to obtain the proton exchange membrane, wherein the proton exchange membrane contains hydrated nano-cerium oxide.

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