阅读说明：本技术 长寿命增强型全氟质子膜及其制备方法 (Long-life enhanced perfluorinated proton membrane and preparation method thereof ) 是由 邹业成 马晓娟 丁涵 张永明 王丽 王振华 于 2020-11-30 设计创作，主要内容包括：本发明涉及一种长寿命增强型全氟质子膜及其制备方法,属于离子交换膜技术领域。本发明所述的长寿命增强型全氟质子膜,由全氟离子交换树脂、多孔聚合物增强材料和添加剂组成,所述添加剂由添加剂A和添加剂B组成；其中添加剂A为由金属和配体形成的金属络合物,其结构为Mx(L)y；所述添加剂的含量为0.02wt％-3wt％；所述多孔聚合物增强材料在质子膜中的体积占比为20％-60％,所制备的质子膜厚度为5-50μm。本发明所述的长寿命全氟质子膜,不仅具有较高的强度和尺寸稳定性,而且具有较长的使用寿命；本发明同时提供了简单易行的制备方法。(The invention relates to a long-life enhanced perfluorinated proton membrane and a preparation method thereof, belonging to the technical field of ion exchange membranes. The long-life enhanced perfluorinated proton membrane consists of perfluorinated ion exchange resin, a porous polymer reinforced material and an additive, wherein the additive consists of an additive A and an additive B; wherein the additive A is a metal complex formed by a metal and a ligand, and has a structure of Mx (L) y; the content of the additive is 0.02-3 wt%; the volume of the porous polymer reinforcing material in the proton membrane is 20-60%, and the thickness of the prepared proton membrane is 5-50 μm. The long-life perfluorinated proton membrane has high strength and dimensional stability and long service life; the invention also provides a simple and feasible preparation method.)

1. A long-life enhanced perfluorinated proton membrane is composed of perfluorinated ion exchange resin, a porous polymer reinforced material and an additive, and is characterized in that: the thickness of the proton membrane is 5-50 μm; the additive consists of an additive A and an additive B, and the content of the additive is 0.02 to 3 weight percent; wherein the additive A is a metal complex formed by a metal and a ligand, and has a structure of Mx (L) y; wherein the metal in the additive a is selected from a metal, a metal oxide, a metal salt, or a combination thereof;

the structure of the ligand in the additive A is one or more of the following structural formulas:

wherein R is₁，R₂，R₃，R₄Are respectively H, OH, CH₃(CH₂)_nO，CH₃(CH₂)_n，NH₂，CH₂OH，C₆H₅，CF₃(CF₂)_n，CF₃(CF₂)_nO, COOH, wherein n is an integer of 0-10;

the structure of the additive B is one or more of the following structural formulas:

wherein R is₁，R₂，R₃，R₄Are respectively H, OH, CH₃(CH₂)_nO，CH₃(CH₂)_n，NH₂，CH₂OH，C₆H₅，CF₃(CF₂)_n，CF₃(CF₂)_nO, wherein n is an integer of 0 to 10.

2. The long life enhanced perfluorinated proton membrane of claim 1, wherein: the metal in the additive A is metal element Mn, Co, Rh, Cu, Ni, Ir, Ag, Ti, Ce, Ru, Cr, Zr, Fe, V, Zn, La, Pt or Pd, or metal compound Pt (NH)₃)₄(NO₃)₂、PtCl₄、WO₃、CeF₃、SiO₂、CeO₂、CePO₄、Ce(NO₃)₃·6H₂O、Ce(SO₄)₂、Ce(OH)₄、(NH₄)₂Ce(NO₃)₆、Ce₂(CO₃)₃·xH₂O、Ce(CH₃COO)₃·xH₂O、CrPO₄、AlPO₄、MnO、MnO₂、Mn₂O₃、MnSO₄、MnCl₂、Mn(NO₃)₂、Mn(CH₃COO)₂·4H₂O、ZnO、ZnCl₂Or Zn (NO)₃)₂One or more of (a).

3. The long life enhanced perfluorinated proton membrane of claim 1, wherein: the molar ratio of the metal M to the ligand L in the additive A is 1:1-1: 5.

4. The long life enhanced perfluorinated proton membrane of claim 1, wherein: the thickness of the porous polymer reinforced material is 4-30 μm, and the volume percentage of the porous polymer reinforced material in the proton membrane is 20-60%.

5. The long life enhanced perfluorinated proton membrane of claim 4, wherein: the additive A is added in an amount of 0.01-2 wt%; the addition amount of the additive B is 0.01-1 wt%.

6. The long life enhanced perfluorinated proton membrane of claim 1, wherein: the perfluorinated ion exchange resin is one or more of long-chain branched perfluorosulfonic acid resin or short-chain branched perfluorosulfonic acid resin.

7. The long life enhanced perfluorinated proton membrane of claim 1, wherein: the number average molecular weight of the perfluorinated ion exchange resin is 15-70 ten thousand, and the exchange capacity is 0.85-1.6 mmol/g.

8. The long life enhanced perfluorinated proton membrane of claim 1, wherein: the porous polymer reinforcing material is one or more of polytetrafluoroethylene, polyvinylidene fluoride-Co-hexafluoropropylene, polyethylene, polypropylene, polyethylene-Co-propylene, polyether sulfone, polyether ketone, polyimide or polybenzimidazole.

9. The long life enhanced perfluorinated proton membrane of claim 1, wherein: the porosity of the porous polymer reinforcement is 75-90%.

10. A method for producing a long-life enhanced perfluoroproton membrane according to any one of claims 1 to 9, characterized by comprising the steps of:

(1) adding perfluorinated ion exchange resin and an additive into a solvent, and performing ultrasonic or mechanical stirring to obtain a dispersion liquid;

(2) and (2) performing solution casting, solution casting and screen printing on the dispersion liquid obtained in the step (1), forming a film on a porous polymer reinforced material substrate by using a blade coating, spraying or dipping mode, and heating to obtain the long-life reinforced perfluorinated proton membrane.

Technical Field

The invention relates to a long-life enhanced perfluorinated proton membrane and a preparation method thereof, belonging to the technical field of ion exchange membranes.

Background

Proton Exchange Membrane Fuel Cells (PEMFCs), which convert reactants, i.e., a fuel (e.g., hydrogen) and an oxidant (e.g., oxygen or air), to generate electric energy, are considered to be the first clean and efficient power generation technology in the 21 st century. Proton exchange membranes are a key material of PEMFCs.

The perfluorinated sulfonic acid proton exchange membrane used at present has good proton conductivity and chemical stability at lower temperature (80 ℃) and higher humidity. However, they also have a number of drawbacks: such as poor dimensional stability, poor mechanical strength, poor chemical stability, etc. The water absorption rate and the size expansion caused by water absorption of the membrane are different under different humidity, and the size of the membrane is changed when the membrane is changed under different working conditions. Such repetition eventually leads to mechanical breakage of the proton exchange membrane. In addition, the positive electrode reaction of fuel cells often produces large amounts of strongly oxidizing species such as hydroxyl radicals and hydrogen peroxide, which attack the unstable end groups of the polymer leading to chain scission and/or SO under dry conditions₃ ^-The groups thereby break the polymer chains. Both attacks degrade the membrane and eventually lead to membrane rupture, thinning or pinhole formation. The membrane degradation rate increases significantly with increasing operating time and decreasing inlet Relative Humidity (RH). Finally, when the operating temperature of the perfluorosulfonic acid membrane is higher than 90 ℃, the proton conductivity of the membrane is drastically reduced due to rapid water loss of the membrane, so that the efficiency of the fuel cell is greatly reduced. Therefore, how to improve the strength, dimensional stability, and proton conductivity at high temperature of the perfluorosulfonic acid proton exchange membrane, and reduce the permeability of the working medium, etc. become important issues facing the fuel cell industry.

To improve the performance and/or durability of the film, several approaches have been proposed to address these issues. For example, in a method (US5547551, US 56565041, US5599614) for filling a Nafion ionic conducting solution in Gore-Select series composite membrane solution developed by w.l.gore company, a polytetrafluoroethylene microporous membrane is added as a reinforcing layer of the membrane, so that the strength and the dimensional stability of the membrane are improved, the membrane has excellent oxidation stability, can be degraded in a fuel cell membrane to play a role in locally retarding, and cannot fundamentally solve the problem.

JP-B-7-68377 also proposes a method of filling a porous medium made of polyolefin with a proton exchange resin, but it has insufficient chemical durability and thus has a problem in long-term stability. And due to the addition of the porous medium without proton conductivity, proton conduction paths are reduced, and the proton exchange capacity of the membrane is reduced.

CN200710013624 and US7259208 disclose perfluorosulfonic acid membranes containing triazine ring cross-linked structures, which also have good mechanical strength and dimensional stability. But have limited ability to improve the film. The properties of the final film do not meet the requirements of use.

Therefore, there is a need to solve the durability problem of the film on the basis of solving the strength and dimensional stability of the film. While the solution to long-term free radical oxidative stability of membranes is to add catalysts in the membrane that can promote free radical degradation, including 1) adding aqueous materials in the membrane for preventing fuel cell operation at low humidity (e.g., US 200701564); 2) adding metal element or alloy with free radical trapping effect into the membrane (such as US 2004043283); 3) the free radical scavenger of phenol and hindered amine is added into the film to eliminate hydroxyl free radical.

Although the above-described techniques can partially solve the problem of radical resistance of the film, they cannot fundamentally solve the problem. Their major difficulties mainly include: 1) the added water-retaining substances have a limited water content and cannot fundamentally increase the humidity of the reaction environment and solve the dehydration problem of the membrane, and the added substances also reduce the strength and conductivity of the membrane: 2) the addition of metal or alloy trapping agents requires a very precise control of the content and distribution in the membrane, since these metallic species, besides having the effect of trapping hydroxyl radicals, also catalyze the degradation of hydrogen peroxide, that is to say they have a dual nature. If the amount is too large, the concentration of hydroxyl radicals in the film increases, and the degradation of the film is further promoted. However, because the metal substance has higher density and hydrophilic surface, the metal substance has spontaneous action due to sedimentation and phase separation aggregation with the perfluorinated ion exchange membrane mainly composed of hydrophobic chains in the membrane preparation process. This phenomenon causes unavoidable increases in the local concentration of the metal element leading to accelerated hydrogen peroxide degradation and deterioration of the film. 3) Some added phenol, hindered amine and other substances are used as polymerization inhibitors in free radical polymerization, namely, the added phenol, hindered amine and other substances have very good reactivity to carbon radicals, but the reactivity to oxygen-containing hydroxyl radicals is greatly reduced. Moreover, they are not protected by themselves which are degraded and lost continuously when scavenging free radicals.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects in the prior art and providing a long-life enhanced perfluorinated proton membrane which not only has higher strength and dimensional stability, but also has longer service life; the invention also provides a simple and feasible preparation method.

The long-life enhanced perfluorinated proton membrane consists of perfluorinated ion exchange resin, a porous polymer reinforced material and an additive, wherein the additive consists of an additive A and an additive B; wherein the additive A is a metal complex formed by a metal and a ligand, and has a structure of Mx (L) y;

the structure of the ligand in the additive A is one or more of the following structural formulas:

wherein R is₁，R₂，R₃，R₄Are respectively H, OH, CH₃(CH₂)_nO，CH₃(CH₂)_n，NH₂，CH₂OH，C₆H₅，CF₃(CF₂)_n，CF₃(CF₂)_nO, COOH, wherein n is an integer of 0-10;

the structure of the additive B is one or more of the following structural formulas:

wherein R is₁，R₂，R₃，R₄Are respectively H, OH, CH₃(CH₂)_nO，CH₃(CH₂)_n，NH₂，CH₂OH，C₆H₅，CF₃(CF₂)_n，CF₃(CF₂)_nO, wherein n is an integer of 0 to 10.

The metal in the additive A is selected from metal, metal oxide, metal salt or combination thereof.

Preferably, the metal in the additive A is a metal element Mn, Co, Rh, Cu, Ni, Ir, Ag, Ti, Ce, Ru, Cr, Zr, Fe, V, Zn, La, Pt or Pd, or a metal compound Pt (NH)₃)₄(NO₃)₂、PtCl₄、WO₃、CeF₃、SiO₂、CeO₂、CePO₄、Ce(NO₃)₃·6H₂O、Ce(SO₄)₂、Ce(OH)₄、(NH₄)₂Ce(NO₃)₆、Ce₂(CO₃)₃·xH₂O、Ce(CH₃COO)₃·xH₂O、CrPO₄、AlPO₄、MnO、MnO₂、Mn₂O₃、MnSO₄、MnCl₂、Mn(NO₃)₂、Mn(CH₃COO)₂·4H₂O、ZnO、ZnCl₂Or Zn (NO)₃)₂One or more of (a).

The molar ratio of the metal M to the ligand L in the additive A is 1:1-1: 5.

The thickness of the porous polymer reinforced material is 4-30 μm, and the volume percentage of the porous polymer reinforced material in the proton membrane is 20% -60%; the additive content is 0.02 wt% -3 wt%.

Preferably, the additive A is added in an amount of 0.01-2 wt%; the addition amount of the additive B is 0.01-1 wt%.

The perfluorinated ion exchange resin is one or more of long-chain branched perfluorosulfonic acid resin or short-chain branched perfluorosulfonic acid resin.

The number average molecular weight of the perfluorinated ion exchange resin is 15-70 ten thousand, preferably 20-60 ten thousand; the exchange capacity is from 0.85 to 1.6mmol/g, preferably from 0.9 to 1.4 mmol/g.

The porous polymer reinforcing material is one or more of polytetrafluoroethylene, polyvinylidene fluoride-Co-hexafluoropropylene, polyethylene, polypropylene, polyethylene-Co-propylene, polyether sulfone, polyether ketone, polyimide or polybenzimidazole.

Preferably, the porosity of the porous polymeric reinforcement is between 75% and 90%, more preferably between 80% and 90%.

The preparation method of the long-life enhanced perfluorinated proton membrane comprises the following steps:

(1) adding perfluorinated ion exchange resin and an additive into a solvent, and obtaining uniform dispersion liquid by means of ultrasonic or mechanical stirring and the like;

(2) and (2) performing solution casting, solution casting and screen printing on the dispersion liquid obtained in the step (1), forming a film on a porous polymer substrate by using a blade coating, spraying or dipping mode, and heating to volatilize the solvent to obtain the long-life enhanced perfluorinated proton membrane.

The thickness of the prepared long-life enhanced perfluorinated proton membrane is 5-50 mu m.

The additive B adopted by the invention is a remover with stronger scavenging ability to oxygen-containing free radicals, especially hydroxyl free radicals, and is particularly suitable for scavenging the generated hydroxyl free radicals in the fuel cell environment. Whereas in additive a metal complex, the metal and ligand components each can potentially act as good radical scavengers or hydrogen peroxide decomposition catalysts (without forming new groups) or both. The presence of the ligand component or the metal component alone under certain conditions may also improve membrane stability, which may adversely affect fuel cell performance. Therefore, the invention uses the ligand and simultaneously adds the metal element with the free radical degradation catalytic function, so that the durability of the catalyst can be improved without causing performance loss. In addition, two different regions with the functions of catalyzing and degrading or eliminating oxygen-containing free radicals are arranged in the same additive, and the two regions are conjugated and connected together through a large pi bond to play a role in synergistically degrading the oxygen-containing free radicals, so that the tolerance of the film is increased in a geometric progression manner.

Compared with the prior art, the invention has the following beneficial effects:

(1) the long-life enhanced perfluorinated proton membrane prepared by the invention not only has higher strength and dimensional stability, but also has longer service life;

(2) the preparation method of the long-life enhanced perfluorinated proton membrane is simple and feasible, and is beneficial to industrial production.

Detailed Description

The present invention is further illustrated by the following examples, which are not intended to limit the practice of the invention.

In the examples, the percentages are by weight unless otherwise specified.

Example 1

Selecting long-chain branched perfluorosulfonic acid resin with exchange capacity of 0.91mmol/g and number average molecular weight of 40 ten thousand, dissolving the resin to form 20 wt% resin dispersion, and respectively adding 1.3 wt% of additive A, formula (VII) and 0.27 wt% of Ce into the dispersion₂(CO₃)₃·xH₂O (VII and Ce)³⁺In a molar ratio of 4:1), 0.3 wt% of additive B of formula (VIII); wherein R in the formula (VII)₁，R₄Is C₆H₅，R₃Is H, R₂Is OH; r in the formula (VIII)₁，R₂Is OCH₃；R₃，R₄Is H. Stirring componentAfter the dispersion is uniform, a polytetrafluoroethylene microporous membrane with the porosity of 95% and the thickness of 4um is soaked in the dispersion, the membrane is taken out after the polytetrafluoroethylene membrane is completely soaked, and the solvent is volatilized after heating to obtain the enhanced perfluorinated proton membrane with the thickness of 12 um.

Example 2

Dissolving a long-chain branched perfluorosulfonic acid resin having an exchange capacity of 1.1mmol/g and a number average molecular weight of 55 ten thousand to form a 17 wt% resin dispersion, and adding 1 wt% of the additive A of the formula (VII), 0.84 wt% of Mn (CH)₃COO)₂·4H₂O (VII and Mn)²⁺In a molar ratio of 2:1), 1% by weight of additive B of formula (VIII); wherein R in the formula (VII)₁，R₃，R₄Is H; r₂Is OH; r in the formula (VIII)₁，R₂Is C₄H₉；R₃，R₄Is H. After the dispersion is uniform, a polyvinylidene fluoride microporous membrane with the porosity of 90% and the thickness of 3um is soaked in the dispersion liquid, the polyvinylidene fluoride membrane is taken out after being completely soaked, and the solvent is volatilized after heating to obtain the enhanced perfluorinated proton membrane with the thickness of 8 um.

Example 3

Dissolving a long-chain branched perfluorosulfonic acid resin having an exchange capacity of 1.2mmol/g and a number average molecular weight of 45 ten thousand to form a 26 wt% resin dispersion, and adding 0.5 wt% of the additive A of the formula (V) and 0.2 wt% of Ce to the dispersion₂(CO₃)₃·xH₂O (V and Ce)³⁺In a molar ratio of 3:1), and 0.8% of additive B of the formula (IX), in which R in the formula (V) is₁Is NH₂；R₂,R₃,R₄Is H, R in formula (IX)₁,R₂Is OH; r₃R₄And H, after uniform dispersion, soaking a polytetrafluoroethylene microporous membrane with porosity of 87% and thickness of 12um in the dispersion, taking out the membrane after the polytetrafluoroethylene membrane is completely soaked, and heating to volatilize the solvent to obtain the enhanced perfluorinated proton membrane of 30 um.

Example 4

Using a short-chain branch perfluorosulfonic acid tree with the exchange capacity of 1.4mmol/g and the number average molecular weight of 23 ten thousandA fat, which is dissolved to form a 30 wt% resin dispersion, to which 1.5 wt% of the formula (IV) in additive A, 0.28 wt% of Mn (CH)₃COO)₂·4H₂O (IV and Mn)²⁺In a molar ratio of 4:1), and 0.5% by weight of additive B of formula (VIII); in the formula (IV), R₁,R₂Is C₆H₅,R₃R₄Is H; r in the formula (VIII)₁,R₃Is C₆H₅；R₂,R₄Is H. After stirring and dispersing uniformly, dipping the polyvinylidene fluoride microporous membrane with the porosity of 85% and the thickness of 18um in the dispersion liquid, taking out the membrane after the polyvinylidene fluoride membrane is completely soaked, and heating to volatilize the solvent to obtain the enhanced perfluorinated proton membrane of 40 um.

Example 5

Dissolving a short-chain branched perfluorosulfonic acid resin having an exchange capacity of 1.25mmol/g and a number average molecular weight of 40 ten thousand to form a 22 wt% resin dispersion, adding to the dispersion 0.1 wt% of an additive B of formula (VIII) wherein R is₁,R₂Is OCH₃；R₃,R₄Is H; and 0.52% by weight of formula (VII), 0.3% by weight of formula (IV) and 0.23% by weight of Ce in additive A₂(CO₃)₃·xH₂O (VII, IV and Ce)³⁺In a molar ratio of 4:1:1), R in the formula (VII)₁,R₃,R₄Is H; r₂Is OH; in the formula (IV), R₁，R₂Is H; r₃,R₄Is C₆H₅. After stirring and dispersing uniformly, soaking a polytetrafluoroethylene microporous membrane with porosity of 82% and thickness of 9um in the dispersion, taking out the membrane after the polytetrafluoroethylene membrane is completely soaked, and heating to volatilize the solvent to obtain the enhanced perfluorinated proton membrane of 15 um.

Example 6

Dissolving a long-chain branched perfluorosulfonic acid resin having an exchange capacity of 0.95mmol/g and a number average molecular weight of 30 ten thousand to form a 35% by weight resin dispersion, adding to the dispersion 0.2% by weight of an additive B of the formula (VIII) in which R is₁,R₂Is C₄H₉；R₃,R₄Is H; and 0.2% by weight of formula (I), 0.16% by weight of Ce (NO) in additive A₃)₃·6H₂O (I and Ce)³⁺In a molar ratio of 3:1), R in the formula (I)₁,R₂,R₃,R₄Is H. After stirring and dispersing uniformly, dipping a polyvinylidene fluoride microporous membrane with porosity of 70% and thickness of 25um in the dispersion liquid, taking out the membrane after the polyvinylidene fluoride membrane is completely soaked, and heating to volatilize the solvent to obtain a reinforced perfluorinated proton membrane of 50 um.

Example 7

Dissolving a long-chain branched perfluorosulfonic acid resin having an exchange capacity of 1.01mmol/g and a number average molecular weight of 35 ten thousand to form a 20 wt% resin dispersion, and adding 0.6 wt% of an additive of formula (VIII) in which R in formula (VIII) is₁,R₂Is C₄H₉；R₃,R₄Is H; and 1% by weight of formula (V), 0.7% by weight of formula (IV) and 0.2% by weight of CeO in additive A₂(V and Ce)^{3 +}In a molar ratio of 5:1), R in the formula (V)₁Is NH₂；R₂,R₃,R₄Is H; in the formula (IV), R₁，R₂Is H; r₃,R₄Is C₆H₅. After stirring and dispersing uniformly, soaking a polytetrafluoroethylene microporous membrane with porosity of 75% and thickness of 5um in the dispersion, taking out the membrane after the polytetrafluoroethylene membrane is completely soaked, and heating to volatilize the solvent to obtain the enhanced perfluorinated proton membrane with the thickness of 20 um.

Example 8

Dissolving a short-chain branched perfluorosulfonic acid resin having an exchange capacity of 1.3mmol/g and a number average molecular weight of 25 ten thousand to form a 26% by weight resin dispersion, adding 0.05% by weight of an additive of the formula (IX) in which R is R in the formula (IX), to the dispersion₁,R₂Is OH; r₃R₄Is H; and 0.25 wt% of formula (I), 0.03 wt% of MnO in additive A₂(I and Mn)³⁺In a molar ratio of 4:1), R in the formula (I)₁,R₂,R₃,R₄Is H. After stirring and dispersing uniformly, dipping a polyvinylidene fluoride microporous membrane with porosity of 78 percent and thickness of 10um in the dispersion liquid,and taking out the polyvinylidene fluoride membrane after the polyvinylidene fluoride membrane is completely soaked, forming the membrane by tape casting, and heating to volatilize the solvent to obtain the enhanced perfluorinated proton membrane of 35 um.

Comparative example 1

Selecting short-chain branch perfluorinated sulfonic acid resin with exchange capacity of 1.25mmol/g and number average molecular weight of 40 ten thousand, dissolving the resin to form 22 wt% resin dispersion, adding no additive, stirring and dispersing uniformly, forming a film by tape casting, and heating to volatilize the solvent to obtain the perfluorinated proton membrane of 25 um.

Durability test of the film:

each MEA was prepared by bonding a suitable membrane sample between the cathode and anode electrodes. The cathode and the anode each had a density of 0.4mg/cm²Pt loading of (a).

To evaluate durability, the MEA sample assembly described above was used with 41cm²An active area fuel cell. 5 different samples were tested simultaneously using the stack. The durability or chemical stability of the MEA samples was evaluated at 30% Relative Humidity (RH) and 90 ℃ under Open Circuit Voltage (OCV). The hydrogen and air gas flow rates were provided at 3.43slpm and 8.37slpm, respectively. OCV of each cell in the stack was monitored over time. When OCV of any one of 5 cells in the stack reaches 0.8V or H₂Crossover is more than 10mA/cm²And ending the test and stopping the test.

The conductivity was measured at 85 ℃ and 50% RH using an electrochemical impedance tester.

Table 1 gives the conductivity, durability test data for the films.

TABLE 1

As shown in Table 1, the enhanced perfluorinated proton membranes of examples 1-8, which have additives added thereto, have much improved durability as compared to comparative example 1. The additive disclosed by the invention can effectively reduce the chemical degradation of ionomer in the membrane, thereby effectively improving the durability of the membrane.

The above-mentioned embodiments are intended to illustrate the technical solutions and advantages of the present invention, and it should be understood that the above-mentioned embodiments are only specific embodiments of the present invention, and are not intended to limit the present invention, and any modifications, additions, equivalents, etc. made within the scope of the principles of the present invention should be included in the scope of the present invention.