Ion conductor dispersion composition, polymer electrolyte membrane, manufacturing method thereof, and membrane-electrode assembly comprising same

Abstract

The present invention relates to an ion conductor dispersion composition, a polymer electrolyte membrane, a manufacturing method thereof, and a membrane-electrode assembly comprising same, and more specifically, to an ion conductor dispersion composition, a polymer electrolyte membrane, a manufacturing method thereof, and a membrane-electrode assembly comprising same, wherein an environmentally-friendly additive solvent is used instead of a conventional chemical-based solvent to improve the solubility and impregnability of the polymer, thereby improving electrochemical and mechanical stability, while being friendly to the environment.

Description

Ion conductor dispersion composition, polymer electrolyte membrane, method for producing same, and membrane-electrode assembly including same

[0001] The present disclosure relates to an ion conductor dispersion composition, a polymer electrolyte membrane, a method for producing the same, and a membrane-electrode assembly including the same, and more particularly, to an ion conductor dispersion composition, a polymer electrolyte membrane, a method for producing the same, and a membrane-electrode assembly including the same, which improves the solubility and impregnation properties of a polymer while being environmentally friendly by using an environmentally friendly additive solvent instead of a conventional chemical-based solvent, thereby improving electrochemical and mechanical stability.

[0002] This disclosure relates to the results of a project (Project ID: 20223030040220) carried out with the support of the Ministry of Trade, Industry and Energy (MOTIE) and the Korea Institute of Energy Technology Evaluation and Planning (KETEP).

[0003] To address the problems of fossil fuel depletion and environmental pollution, efforts are being made to conserve fossil fuels by improving their efficiency and to apply renewable energy to more fields.

[0004] For example, a fuel cell is a battery equipped with a power generation system that directly converts chemical reaction energy, such as the oxidation / reduction reaction of hydrogen and oxygen contained in hydrocarbon fuels such as methanol, ethanol, and natural gas, into electrical energy. Due to its high energy efficiency and environmentally friendly characteristics of low pollutant emissions, it is attracting attention as a next-generation clean energy source that can replace fossil energy.

[0005] Among them, the proton exchange membrane fuel cell (PEMFC) using a polymer electrolyte can directly convert chemical energy into electrical energy and emits non-toxic substances such as water, so it is receiving considerable attention as an alternative energy system for automobiles and portable home appliances.

[0006] Meanwhile, with the growing demand for alternative energy sources to replace fossil fuels, interest in highly efficient, inexpensive, and environmentally friendly energy conversion and storage systems is growing. Fuel production through water electrolysis, with its high potential for commercialization, is attracting significant attention as a key alternative that addresses environmental and energy concerns. Water electrolysis is a technology that electrochemically decomposes water to produce hydrogen and oxygen.

[0007] Among them, in the system of a proton exchange membrane water electrolysis cell (PEMWE), the membrane electrode assembly (MEA) that actually generates hydrogen has a structure in which an oxygen generation electrode, which is an electrode where an oxygen generation reaction occurs, and a hydrogen generation electrode, where a hydrogen generation reaction occurs, are positioned with a polymer electrolyte membrane containing a hydrogen ion conductive polymer in between.

[0008] These fuel cells and electrolytic cells are commonly called electrochemical cells, and among them, in the system of polymer electrolyte fuel cells or polymer electrolyte electrolytic cells that use polymer electrolyte membranes, the representative polymer electrolyte membrane (PEM) material is Nafion from DuPont, USA. ® ) can be used as a perfluorinated sulfonic acid ionomer (PFSA).

[0009] PFSA is composed of a polytetrafluoroethylene (PTFE) main chain with excellent chemical durability and a perfluorovinyl ether side chain containing a sulfate group (-SO3H) with proton conductivity as a terminal group.

[0010] The polymer's main chain has a crystalline structure, its side chains have an amorphous structure, and its terminal groups form ion-water transport channels. Therefore, depending on the length of the main chain and terminal repeating units and the side chains, the ion-water transport channels form differently, resulting in different ionic conductivity, mechanical permeability, and mechanical, chemical, and thermal properties.

[0011] Due to this structure, the solvents available for manufacturing electrolyte membranes are limited, and the commonly used water / alcohol system requires an alcohol solvent for impregnation into the porous support, and depending on the ratio, it affects the microstructure such as the pore size, shape, and surface topography of the electrolyte membrane, but has low impregnation and low ionic conductivity due to the dispersion form, low solid content, and low dispersion stability.

[0012] Chemical-based solvents such as N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), and dimethylacetamide (DMAc) other than the above water / alcohol system have high impregnation properties and high ionic conductivity due to their solution form and high solid content, but they are harmful to the human body and can cause environmental pollution, and have the problem of increasing the cost of wastewater treatment or purification facilities.

[0013] Accordingly, there is a need for a solvent that can replace the chemical-based solvents while having similar properties to the chemical-based solvents and being non-toxic.

[0014] According to one embodiment, an ionic conductor dispersion composition is provided that is environmentally friendly and improves the solubility and impregnation properties of a polymer, thereby improving electrochemical and mechanical stability, by using an environmentally friendly additive solvent instead of a conventional chemical-based solvent.

[0015] According to another embodiment, a polymer electrolyte membrane is provided.

[0016] According to another embodiment, a method for manufacturing the polymer electrolyte membrane is provided.

[0017] An ion conductor dispersion composition according to one embodiment comprises an ion conductor, a solvent, an environmentally friendly additive solvent, and a nonsolvent, wherein the pKa value of the environmentally friendly additive solvent is in the range of 0 to 7.5, and the environmentally friendly additive solvent has a dispersion term of the Hansen solubility parameter of 16 MPa. 0.5 Above, the polarity term is 6 MPa 0.5 Above, the hydrogen bonding term is 13 MPa 0.5 Satisfy the following:

[0018] The above eco-friendly additive solvent may have a score within the range of 4 to 10 in all items according to the solvent selection guide criteria of GSK.

[0019] The above-mentioned eco-friendly additive solvent is a polar aprotic solvent, and the polar aprotic solvent may be gamma butyrolactone, methyl L-lactate, gamma valerolactone, ethyl lactate, dimethyl carbonate, cyclic carbonate, succinic acid, diformylxylose, pentanoic acid, 5-(dimethylamino)-2-methyl-5-oxo-, methyl ester (CAS No. 1174627-68-9), dihydrolevoglucosenone, methyl sesamol, or a combination thereof.

[0020] The distance (R) between the Hansen solubility parameter of the ion conductor and the Hansen solubility parameter of the mixture of the solvent, the eco-friendly additive solvent, and the nonsolvent, calculated according to the following mathematical formula 1 a ) is 0.1 MPa 0.5 Up to 30 MPa 0.5 is within the scope of,

[0021] The dispersion term, polarity term and hydrogen bond term of the Hansen solubility parameter of the mixture of the above solvent, the above eco-friendly additive solvent and the above non-solvent can be calculated according to the following mathematical equations 2-1 to 2-3.

[0022] [Mathematical Formula 1]

[0023]

[0024] In the above mathematical formula 1,

[0025] Above δ d1 (Unit: MPa 0.5 ) is the dispersion term of the above ionic conductor,

[0026] Above δ d2 (Unit: MPa 0.5 ) is the dispersion term of the above mixture,

[0027] Above δ p1 (Unit: MPa 0.5 ) is the polarity term of the above ion conductor,

[0028] Above δ p2 (Unit: MPa 0.5 ) is the polarity of the mixture,

[0029] Above δ h1 (Unit: MPa 0.5 ) is the hydrogen bond term of the above ion conductor,

[0030] Above δ h2 (Unit: MPa 0.5 ) is the hydrogen bonding term of the above mixture:

[0031] [Equation 2-1]

[0032]

[0033] [Equation 2-2]

[0034]

[0035] [Equation 2-3]

[0036]

[0037] In mathematical expressions 2-1 to 2-3, δd2 is the dispersion term of the mixture, and δ p2 is the polar term of the mixture, and δ h2 is the hydrogen bonding term of the mixture, w1 is the weight of the solvent, w2 is the weight of the eco-friendly additive solvent, w3 is the weight of the non-solvent, and δ d,1 , δ p,1 , δ h,1 are the dispersion term, polarity term, and hydrogen bonding term of the Hansen solubility parameter of the solvent, respectively, and δ d,2 , δ p,2 , δ h,2 are the dispersion term, polarity term, and hydrogen bonding term of the Hansen solubility parameter of the eco-friendly additive solvent, and δ d,3 , δ p,3 , δ h,3 are the dispersion term, polarity term, and hydrogen bonding term of the Hansen solubility parameter of the non-solvent.

[0038] The above-mentioned eco-friendly additive solvent is included in an amount of 3 to 20 wt% based on the total weight of the ion conductor dispersion composition, the solvent is included in an amount of 180 to 1000 wt% based on 100 wt% of the eco-friendly additive solvent, and the non-solvent may be included in an amount of 100 to 500 wt% based on 100 wt% of the eco-friendly additive solvent.

[0039] The viscosity measured using a flow sweep measurement protocol and at 25°C conditions using rheometer equipment can be in the range of 200 cP to 1100 cP.

[0040] The change rate of the contact angle for the support calculated according to Equation 1 below can be 30% to 60%.

[0041] [Formula 1]

[0042] Rate of change of contact angle on the support = (ab) / a 100

[0043] In Equation 1, a is the contact angle with respect to the support when the ion conductor dispersion composition is dropped on the support for the first time, and b is the contact angle with respect to the support when the ion conductor dispersion composition is dropped on the support for the 200th time.

[0044] The size of the ion conductor dispersion particles in the above ion conductor dispersion composition may be in the range of 500 nm to 2000 nm.

[0045] The polydispersity index of the ion conductor in the above ion conductor dispersion composition may be in the range of 0.9 to 1.5.

[0046] A method for manufacturing a polymer electrolyte membrane according to another embodiment includes preparing a first mixture by mixing an ion conductor with a solvent, adding an environmentally friendly additive solvent to the first mixture and mixing the mixture to prepare a second mixture, adding a non-solvent to the second mixture and mixing the mixture to prepare an ion conductor dispersion composition, coating the ion conductor dispersion composition on a substrate, and then performing drying and heat treatment to prepare a polymer electrolyte membrane, wherein the environmentally friendly additive solvent has a pKa value in the range of 0 to 7.5, and the environmentally friendly additive solvent has a dispersion term of the Hansen solubility parameter of 16 MPa. 0.5 Above, the polarity term is 6 MPa 0.5 Above, the hydrogen bonding term is 13 MPa 0.5 Satisfy the following:

[0047] After coating the ion conductor dispersion composition on the substrate, and before performing drying and heat treatment, the method may further include placing a porous support on the substrate coated with the ion conductor dispersion composition, and re-coating the ion conductor dispersion composition on the porous support.

[0048] The above drying is performed at a temperature within the range of 60°C to 120°C, and the above heat treatment can be performed at a temperature within the range of 150°C to 220°C when a fluorine-based ion conductor is used, and can be performed at a temperature within the range of 80°C to 500°C when a hydrocarbon-based ion conductor is used.

[0049] According to another embodiment, a polymer electrolyte membrane includes a porous support including a plurality of pores, and an ion conductor filling the pores of the porous support, and a haze measured by a light transmittance device may be 0.1% to 10%.

[0050] The above polymer electrolyte membrane may have a total light transmittance (Tt) of 90% or more as measured by a total light transmittance device.

[0051] The polymer electrolyte membrane may have a tensile strength in the longitudinal direction (MD) of 35 MPa or more and a tensile strength in the transverse direction (TD) of 30 MPa or more.

[0052] The above polymer electrolyte membrane may have an absolute value of the difference between the elongation in the longitudinal direction (MD) and the elongation in the transverse direction (TD) of 50% or less.

[0053] The polymer electrolyte membrane may have a surface-wise wet expansion coefficient of 20% or less measured at 15°C to 25°C.

[0054] The polymer electrolyte membrane may have a surface-wise wet expansion coefficient of 40% or less measured at 75 to 85°C.

[0055] According to another embodiment, a membrane-electrode assembly comprises: the polymer electrolyte membrane; a hydrogen electrode positioned on one side of the polymer electrolyte membrane; and an air electrode positioned on the other side of the polymer electrolyte membrane.

[0056] An electrochemical cell according to another embodiment comprises the membrane-electrode assembly.

[0057] An ion conductor dispersion composition according to one embodiment uses an environmentally friendly additive solvent instead of a conventional chemical-based solvent, thereby improving the solubility and impregnation properties of a polymer while being environmentally friendly, thereby improving electrochemical and mechanical stability.

[0058] FIG. 1 is a graph showing the results of evaluating the IV characteristics of membrane-electrode assemblies including polymer electrolyte membranes manufactured in Examples 1 to 6 and Comparative Examples 1 and 2.

[0059] Hereinafter, embodiments of the present disclosure will be described in detail so that those skilled in the art can easily implement the present disclosure. However, the present disclosure may be implemented in various different forms and is not limited to the embodiments described herein.

[0060] As used herein, “combination thereof” means a mixture, laminate, composite, copolymer, alloy, blend, reaction product, etc. of the components.

[0061] It should be understood that the terms “include,” “comprising,” or “having” used in this specification are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0062]

[0063] 1. Ionic conductor dispersion composition

[0064] An ionic conductor dispersion composition according to one embodiment comprises an ionic conductor, a solvent, and an environmentally friendly additive solvent.

[0065] In this specification, the term environmentally friendly additive solvent refers to a solvent that minimizes the negative impact of the solvent on the environment from chemical production to solvent disposal.

[0066] The above eco-friendly additive solvents follow the GSK solvent selection guide standards (2016 ver.).

[0067] [Categories classified according to GSK's solvent selection guide]

[0068] - waste

[0069] - Environmental impact

[0070] - Health

[0071] - Safety assessment (safety)

[0072] The above "waste" category includes incineration items, recycling items, biological treatment items, and VOC emission items in detail, the above "environmental impact" category includes water pollution items and air pollution items in detail, the above "health" category includes exposure possibility items and health hazard items in detail, and the above "safety assessment" category includes flammability (explosion potential) items and reactivity (stability) items in detail. According to GSK's solvent selection guide criteria, each category is evaluated from 1 to 10, with 10 indicating no problems related to each category, and 1 indicating a case where there are well-known problems related to each category. Each category is evaluated from 1 to 10, and as a result, it is evaluated as Major known issue, Some known issues, and Few known issue according to the evaluation values ​​below.

[0073] Specifically, in each category, scores 1 through 3 are "Major known issue," scores 4 through 7 are "Some known issues," and scores 8 through 10 are "Few known issues."

[0074] In this specification, an environmentally friendly additive solvent means one that scores within the range of 4 to 10 in all items according to the solvent selection guide criteria of GSK.

[0075] Table 1 below shows that all detailed items in each category classified below were evaluated with values ​​from 1 to 10 according to the solvent selection guide criteria of GSK for each of water, gamma butyrolactone, methyl L-lactate, N-methyl-2-pyrrolidone, and propyl alcohol.

[0076] Terminology in this specification Waste Environment Health Safety Incineration Recycling Biomass VOC Water Air Exposure Health Flammability Reactivity / Stability Treatment Emission Pollution Potential for Pollution Hazardous Explosion Potential Solvent 4246108109810 Eco-friendly Added Solvent Gamma Butyrolactone 8710810646910 Methyl L-Lactate 46489610689 Chemical-based Solvent N-Methyl-2-pyrrolidone 343101061999 Propyl Alcohol 5336104107810

[0077] In Table 1 above, it can be seen that chemical-based solvents, N-methyl-2-pyrrolidone and propyl alcohol, were evaluated with values ​​less than 4 in the waste and health categories.

[0078] On the other hand, it can be confirmed that gamma butyrolactone and methyl L-lactate can be considered as environmentally friendly additive solvents as referred to herein, as they were evaluated to have values ​​of 4 or higher in all items of each category.

[0079] That is, the above-mentioned eco-friendly additive solvent is evaluated as having a value within the range of 4 to 10 in all items of the categories classified below according to the solvent selection guide standards of GSK, and thus can resolve the problems of existing chemical-based solvents causing harm to the human body and environmental pollution, and is eco-friendly compared to existing chemical-based solvents, while having the same or superior physical properties as or better than those of existing chemical-based solvents.

[0080] The pKa of the above-mentioned eco-friendly additive solvent is characterized by being 0 to 7.5, specifically, the pKa of the above-mentioned eco-friendly additive solvent may be 1 to 7, 2 to 6, 3 to 5, or 3.5 to 4.5. When a polymer electrolyte membrane is manufactured using an eco-friendly additive solvent that satisfies the above-mentioned pKa value, the SO of the polymer electrolyte membrane 3- It is possible to maintain a high protonation level of the polymer electrolyte membrane, thereby improving the performance of the polymer electrolyte membrane.

[0081] The above eco-friendly additive solvent has a dispersion term (δ) of the Hansen solubility parameter d ), polar term (δ p ) and hydrogen bond term (δ h ) are each within a predetermined range. At this time, the Hansen solubility parameter of the eco-friendly additive solvent may be based on a known value through the Hansen solubility parameter of each substance (e.g., Charles Hansen, "Hansen Solubility Parameters: A User's Handbook" CRC Press (2007), "The CRC Handbook and Solubility Parameters and Cohesion Parameters," Allan FM Barton (1999)), or a value calculated by commercial software such as Molecular Modeling Pro, Dynacomp Software, or HSPiP.

[0082] As an example, the Hansen solubility parameter estimates at 25°C by the computer software HANSEN SOLUBILITY PARAMETERS IN PRACTICE (HSPiP) VER 5.2.06 and SMILES of the software ChemDraw (a function for estimating Hansen solubility parameters from the molecular structure of a solvent) can be cited.

[0083] The above dispersion term is 16 MPa 0.5It is characterized by the above. For example, the lower limit of the above dispersion term is 16 MPa 0.5 , 16.5 MPa 0.5 , 17 MPa 0.5 , 17.5 MPa 0.5 or 18 MPa 0.5 It can be of the degree, and its upper limit is not limited, for example, 20 MPa 0.5 , 19 MPa 0.5 , 18 MPa 0.5 , 17 MPa 0.5 or 16 MPa 0.5 The variance may be greater than or equal to any one of the lower limits described above; or may have a range greater than or equal to any one of the lower limits described above and less than or equal to any one of the upper limits described above.

[0084] The above polarity is 6 MPa 0.5 It is characterized by the above. For example, the lower limit of the polarity term is 6 MPa 0.5 , 6.5 MPa 0.5 , 7 MPa 0.5 , 8 MPa 0.5 , 9 MPa 0.5 , 10 MPa 0.5 , 11 MPa 0.5 , 12 MPa 0.5 , 13 MPa 0.5 , 14 MPa 0.5 , 15 MPa 0.5 or 16 MPa 0.5 It can be of the degree, and its upper limit is not limited, for example, 25.5 MPa 0.5 , 21.7 MPa 0.5 , 19 MPa 0.5 18 MPa 0.5 , 17 MPa 0.5 or 16 MPa 0.5The polarity may be greater than or equal to any one of the lower limits described above; or may have a range greater than or equal to any one of the lower limits described above and less than or equal to any one of the upper limits described above.

[0085] The above hydrogen bonding term is 13 MPa 0.5 It is characterized by the following. For example, the lower limit of the hydrogen bond term is not limited, but is, for example, 0 MPa. 0.5 , 0.5 MPa 0.5 , 1 MPa 0.5 , 2MPa 0.5 , 2 MPa 0.5 , 3 MPa 0.5 , 4 MPa 0.5 , 5 MPa 0.5 , 6 MPa 0.5 , 7 MPa 0.5 , 8 MPa 0.5 , 9 MPa 0.5 or 10 MPa 0.5 It can be up to 13 MPa. 0.5 , 12 MPa 0.5 , 11 MPa 0.5 , 10 MPa 0.5 , 9.8 MPa 0.5 , 9.6 MPa 0.5 , 9.4 MPa 0.5 , 9.2 MPa 0.5 , 9 MPa 0.5 , 8.8 MPa 0.5 , 8.6 MPa 0.5 , 8.4 MPa 0.5 , 8.2 MPa 0.5 , 8 MPa 0.5 , 7.8 MPa 0.5 or 7.6 MPa 0.5The hydrogen bonding term may have a range that is less than or greater than any one of the upper limits described above; or greater than or greater than any one of the lower limits described above, and less than or equal to any one of the upper limits described above.

[0086] By including an environmentally friendly additive solvent that satisfies the aforementioned toxicity values ​​and Hansen solubility parameters, the solubility and impregnation properties of the polymer can be improved while being environmentally friendly, thereby improving electrochemical and mechanical stability.

[0087] The above-mentioned eco-friendly additive solvent is evaluated to have a value within the range of 4 to 10 in all items of each category classified according to the solvent selection guide criteria of GSK as described above, and its type is not limited as long as it satisfies the Hansen solubility parameter value. Although Table 1 above only shows the evaluated values ​​of all items of each category classified according to the solvent selection guide criteria of GSK for gamma butyrolactone and methyl L-lactate used in the examples below, the types of the above-mentioned eco-friendly additive solvents are not limited thereto.

[0088] For example, the environmentally friendly additive solvent may be a polar aprotic solvent. The aprotic solvent refers to a solvent that does not have a functional group that allows one or more hydrogen atoms in the solvent molecule to be removed as a proton.

[0089] The polar aprotic solvent may be γ-Butyrolactone, methyl L-lactate, γ-Valerolactone, ethyl lactate, dimethyl carbonate, cyclic carbonate, succinic acid, diformylxylose, pentanoic acid, 5-(dimethylamino)-2-methyl-5-oxo-, methyl ester (CAS No. 1174627-68-9), dihydrolevoglucosenone, methyl sesamol, or a combination thereof. For example, pentanoic acid 5-(dimethylamino)-2-methyl-5-oxo methyl ester is commercially available as PolarClean from Rhodiasolv, and dihydrolevoglucocenone is commercially available as Hydro-LGE (Cyrene™).

[0090] The above ion conductor may include a fluorine-based ion conductor, a hydrocarbon-based ion conductor, and a combination thereof.

[0091] The above fluorine-based ion conductor is (i) a fluorine-based polymer containing fluorine in the main chain, having a cation exchange group or an anion exchange group, or (ii) a partially fluorinated polymer such as a polystyrene-graft-ethylenetetrafluoroethylene copolymer, a polystyrene-graft-polytetrafluoroethylene copolymer, etc.

[0092] The above cation exchange group is a functional group capable of transferring a cation such as a proton, and may be, for example, an acidic group such as a sulfonic acid group, a carboxyl group, a boronic acid group, a phosphoric acid group, an imide group, a sulfonimide group, or a sulfonamide group.

[0093] The above anion exchange group is a functional group capable of transferring anions such as hydroxyl ions, carbonate ions, or bicarbonate ions.

[0094] Examples of the above fluorinated ion conductors include, but are not limited to, (i) poly(perfluorosulfonic acid), (ii) poly(perfluorocarboxylic acid), (iii) copolymers of tetrafluoroethylene and fluorovinyl ether containing sulfonic acid groups, and (iv) defluorinated sulfurized polyether ketones.

[0095] The above hydrocarbon-based ion conductor is a hydrocarbon-based polymer having a cation exchange group or an anion exchange group (for example, a hydrocarbon-based polymer including in the main chain imidazole, benzimidazole, polyamide, polyamideimide, polyimide, polyacetal, polyethylene, polypropylene, acrylic resin, polyester, polysulfone, polyether, polyetherimide, polyester, polyethersulfone, polyetherimide, polycarbonate, polystyrene, polyphenylene sulfide, polyetheretherketone, polyetherketone, polyarylethersulfone, polyphosphazene, polyphenylquinoxaline, or a combination thereof).

[0096] The above hydrocarbon ion conductors are sulfonated polyimide (S-PI), sulfonated polyarylethersulfone (S-PAES), sulfonated polyetheretherketone (SPEEK), sulfonated polybenzimidazole (SPBI), sulfonated polysulfone (S-PSU), sulfonated polystyrene (S-PS), sulfonated polyphosphazene, sulfonated polyquinoxaline, sulfonated polyketone, sulfonated polyphenylene oxide, sulfonated polyether sulfone, sulfonated polyether ketone, sulfonated Sulfonated polyphenylene sulfone, sulfonated polyphenylene sulfide, sulfonated polyphenylene sulfide sulfone, sulfonated polyphenylene sulfide sulfone nitrile, sulfonated polyarylene ether, sulfonated polyarylene ethernitrile, sulfonated polyarylene ether ether nitrile,and polyarylene ether sulfone ketones, but are not limited to these.

[0097] The above solvent may be a polar solvent.

[0098] The polar solvent may include water, tetrahydrofuran, 1,4-dioxane, dimethyl acetamide, dimethyl formamide, dimethyl sulfoxide, methylene chloride, acetonitrile, propylene carbonate, N-methyl-2-pyrrolidone, ethyl acetate, and mixtures thereof.

[0099] For example, the solvent may be water.

[0100] The above ion conductor dispersion composition may further include a non-solvent different from the solvent.

[0101] The non-solvent may be an alcohol. For example, it may be methanol, ethanol, propanol, butanol, or a combination thereof.

[0102] The above ion conductor dispersion composition has a distance (R) between the Hansen solubility parameter of the ion conductor and the Hansen solubility parameter of a mixture including the eco-friendly additive solvent. a ) can be within a certain range.

[0103] The above distance (R) a ) is calculated according to the following mathematical formula 1.

[0104] [Mathematical Formula 1]

[0105]

[0106] In the above mathematical expression 1, the δ d1 (Unit: MPa 0.5 ) is the dispersion term of the ionic conductor, and the δ d2 (Unit: MPa 0.5 ) is the dispersion term of the above mixture, and the above δ p1 (Unit: MPa 0.5 ) is the polarity term of the ionic conductor, and the δ p2 (Unit: MPa 0.5 ) is the polarity term of the above mixture, and the above δ h1 (Unit: MPa 0.5 ) is the hydrogen bonding term of the ion conductor, and the δ h2 (Unit: MPa 0.5 ) is the hydrogen bonding term of the above mixture.

[0107] In mathematical expression 1, the dispersion term, polarity term, and hydrogen bonding term of the ion conductor are known. In mathematical expression 1, the Hansen solubility parameters for the solvent, eco-friendly additive solvent, and nonsolvent included in the mixture are known, and the dispersion term (δ) of the mixture according to the weight ratio of each component included in the mixture d2 ), polar term (δ p2 ) and hydrogen bond term (δ h2 ) can be calculated according to the following mathematical formulas 2-1 to 2-3, respectively.

[0108] [Equation 2-1]

[0109]

[0110] [Equation 2-2]

[0111]

[0112] [Equation 2-3]

[0113]

[0114] In mathematical expressions 2-1 to 2-3, δ d2 is the dispersion term of the mixture, and δ p2 is the polar term of the mixture, and δ h2is the hydrogen bonding term of the mixture, w1 is the weight of the solvent, w2 is the weight of the eco-friendly additive solvent, w3 is the weight of the non-solvent, and δ d,1 , δ p,1 , δ h,1 are the dispersion term, polarity term, and hydrogen bonding term of the Hansen solubility parameter of the solvent, respectively, and δ d,2 , δ p,2 , δ h,2 are the dispersion term, polarity term, and hydrogen bonding term of the Hansen solubility parameter of the eco-friendly additive solvent, and δ d,3 , δ p,3 , δ h,3 are the dispersion term, polarity term, and hydrogen bonding term of the Hansen solubility parameter of the non-solvent.

[0115] That is, the above distance (R a ) is the result of calculating the dispersion term, polarity term, and hydrogen bond term of the mixture calculated according to the above mathematical formulas 2-1 to 2-3 by substituting them into the above mathematical formula 1. The distance (R a ) is 0.1 MPa 0.5 , 0.5 MPa 0.5 , 1 MPa 0.5 , 1.5 MPa 0.5 , 2 MPa 0.5 , 2.5 MPa 0.5 , 3 MPa 0.5 , 3.5 MPa 0.5 , 4 MPa 0.5 , 4.5 MPa 0.5 , 5 MPa 0.5 , 6 MPa 0.5 , 8 MPa 0.5 , 8 MPa 0.5 , 9 MPa 0.5 , 10 MPa 0.5 , 11 MPa 0.5 , 12 MPa 0.5 , 13 MPa 0.5 , 14 MPa 0.5 , 15 MPa 0.5 , 16 MPa 0.5 , 17 MPa 0.5 , 18 MPa 0.5 , 19 MPa0.5 or 20 MPa 0.5 It can be of the order of 30 MPa, and its upper limit is 0.5 , 29 MPa 0.5 , 28 MPa 0.5 , 27 MPa 0.5 , 26 MPa 0.5 , 25 MPa 0.5 , 24 MPa 0.5 , 23 MPa 0.5 , 22 MPa 0.5 , 21 MPa 0.5 , 20 MPa 0.5 , 19 MPa 0.5 , 18 MPa 0.5 or 17 MPa 0.5 It could be the extent of it.

[0116] The above distance (R) a ) may have a range that is greater than or equal to any one of the lower limits described above; less than or equal to any one of the upper limits described above; or greater than or equal to any one of the lower limits described above and less than or equal to any one of the upper limits described above.

[0117] The above distance (R) a ) can be appropriately adjusted to ensure that the weight ratio of each component included in the mixture is within the aforementioned range.

[0118] The above-mentioned eco-friendly additive solvent may be included within a predetermined range relative to the total weight of the ion conductor dispersion composition.

[0119] The lower limit of the environmentally friendly additive solvent relative to the total weight of the ion conductor dispersion composition may be about 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, or 15 wt%, and the upper limit may be about 20 wt%, 19 wt%, 18 wt%, 17 wt%, 16 wt%, 15 wt%, 14 wt%, 13 wt%, 12 wt%, 11 wt%, 10 wt%, 9 wt%, 8 wt%, 7 wt%, or 6 wt%.

[0120] The above-mentioned eco-friendly additive solvent may have a range of more than or exceeding any one of the lower limits described above, less than or equal to any one of the upper limits described above, or more than or exceeding any one of the lower limits described above and less than or equal to any one of the upper limits described above, relative to the total weight of the ion conductor dispersion composition.

[0121] The above solvent may be included within a predetermined range relative to 100 parts by weight of the above eco-friendly additive solvent.

[0122] For example, for 100 parts by weight of the eco-friendly additive solvent, the lower limit of the solvent may be about 180 parts by weight, 190 parts by weight, 200 parts by weight, 210 parts by weight, 220 parts by weight, 230 parts by weight, 240 parts by weight, 250 parts by weight, 260 parts by weight, 270 parts by weight, 280 parts by weight, 290 parts by weight, 300 parts by weight, 400 parts by weight, 500 parts by weight, 600 parts by weight, 700 parts by weight, 800 parts by weight, or 900 parts by weight, and the upper limit of the solvent may be about 1000 parts by weight, 990 parts by weight, 980 parts by weight, 970 parts by weight, 960 parts by weight, 950 parts by weight, 940 parts by weight, 930 parts by weight, 920 parts by weight, 910 parts by weight, 900 It can be about 800 parts by weight, 700 parts by weight, 600 parts by weight, 500 parts by weight, 400 parts by weight, 300 parts by weight, 290 parts by weight, 280 parts by weight, 270 parts by weight, 260 parts by weight, 250 parts by weight or 240 parts by weight.

[0123] The solvent may have a range of more than or exceeding any one of the lower limits described above, relative to 100 parts by weight of the eco-friendly additive solvent; less than or equal to any one of the upper limits described above; or more than or exceeding any one of the lower limits described above and less than or equal to any one of the upper limits described above.

[0124] Additionally, the non-solvent may be included within a predetermined range relative to 100 parts by weight of the eco-friendly additive solvent.

[0125] With respect to 100 parts by weight of the above-mentioned eco-friendly additive solvent, the lower limit of the non-solvent may be about 100 parts by weight, 105 parts by weight, 110 parts by weight, 115 parts by weight, 120 parts by weight, 125 parts by weight, 130 parts by weight, 135 parts by weight, 140 parts by weight, 145 parts by weight, 150 parts by weight, 160 parts by weight, 170 parts by weight, 180 parts by weight, 190 parts by weight, 200 parts by weight, 250 parts by weight, 300 parts by weight, 350 parts by weight or 400 parts by weight, and the upper limit may be about 500 parts by weight, 490 parts by weight, 480 parts by weight, 470 parts by weight, 460 parts by weight, 450 parts by weight, 440 parts by weight, 430 parts by weight, 420 parts by weight, 410 parts by weight. It can be about 400 parts by weight, 300 parts by weight, 200 parts by weight or 150 parts by weight.

[0126] The non-solvent may have a range of more than or exceeding any one of the lower limits described above, relative to 100 parts by weight of the environmentally friendly additive solvent; less than or equal to any one of the upper limits described above; or more than or exceeding any one of the lower limits described above and less than or equal to any one of the upper limits described above.

[0127] When the above solvent, the above eco-friendly additive solvent and the above non-solvent are included in a weight ratio within the above-mentioned range, the above-mentioned distance (R a ) can be satisfied, and accordingly, the purpose of the present disclosure can be achieved.

[0128] The above ion conductor dispersion composition may have a viscosity within a predetermined range, even though it is a ternary mixture. The method for measuring the viscosity is according to the method described in the "Viscosity Measurement" section of Evaluation Example 1 below.

[0129] The lower limit of the viscosity may be about 200 cP, 210 cP, 220 cP, 230 cP, 240 cP, 250 cP, 260 cP, 270 cP, 280 cP, 290 cP, 300 cP, 350 cP, 400 cP, 450 cP, 500 cP, 600 cP, 700 cP, 800 cP, 900 cP or 1000 cP, and the upper limit is not specifically limited, but may be about 1100 cP, 1000 cP, 950 cP, 900 cP, 850 cP, 800 cP, 750 cP, 700 cP, 650 cP, 600 cP, 550 cP, It can be around 500 cP, 400 cP, 350 cP, 300 cP, 290 cP, 280 cP, 270 cP, 260 cP or 250 cP.

[0130] The viscosity may be greater than or equal to any one of the lower limits described above; less than or equal to any one of the upper limits described above; or greater than or equal to any one of the lower limits described above and less than or equal to any one of the upper limits described above. When the ion conductor dispersion composition has a viscosity within the aforementioned range, it can be impregnated into the support without deterioration in impregnation during the production of a reinforced composite membrane.

[0131] In addition, the ion conductor dispersion composition may have excellent impregnation properties. The impregnation properties can be expressed as a change rate in the contact angle of the ion conductor dispersion composition with respect to the support. The change rate in the contact angle of the ion conductor dispersion composition with respect to the support can be calculated according to the following Equation 1.

[0132] [Formula 1]

[0133] Rate of change of contact angle on the support = (ab) / a 100

[0134] In Equation 1, a is the contact angle with respect to the support when the ion conductor dispersion composition is dropped on the support for the first time, and b is the contact angle with respect to the support when the ion conductor dispersion composition is dropped on the support for the 200th time.

[0135] The measurement method of the above a and b follows the method described in the “Measurement of contact angle of ion conductor dispersion composition on support” item of Evaluation Example 2 below.

[0136] The lower limit of the change rate of the contact angle for the above support may be about 30%, 35%, 40%, 45%, 50% or 55%, and the upper limit may be about 60%, 59%, 58%, 57%, 56%, 55%, 54%, 53%, 52%, 51%, 50%, 49%, 48%, 47%, 46%, 45%, 44%, 43%, 42%, 41%, 40%, 39%, 38%, 37%, 36% or 35%.

[0137] The rate of change of the contact angle for the support may be less than or equal to any one of the upper limits described above; or may be greater than or equal to any one of the lower limits described above, and less than or equal to any one of the upper limits described above. When the rate of change of the contact angle for the support is within the above range, the degree of impregnation and the rate of impregnation for the support can be appropriately secured, and it can be easily applied to pilot facilities in the future.

[0138] The size of the ion conductor dispersion particles in the above ion conductor dispersion composition may be within a predetermined range. The method for measuring the size of the ion conductor dispersion particles is according to the method described in the “Measurement of Dispersed Particle Size” section of Evaluation Example 3 below.

[0139] The lower limit of the size of the ion conductor dispersion particles may be about 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, 850 nm, 900 nm, 950 nm, 1000 nm, 1050 nm, 1100 nm, 1150 nm, 1200 nm, 1250 nm, 1300 nm, 1350 nm or 1400 nm, and the upper limit may be about 2000 nm, 1900 nm, 1800 nm, 1700 nm, 1600 nm, 1500 nm, 1400 nm, 1300 nm, 1200 nm, 1100 nm, 1000 nm, 900 nm, 800 nm or 750 nm.

[0140] The size of the ion conductor dispersion particles in the ion conductor dispersion composition may be greater than or equal to any one of the lower limits described above; less than or equal to any one of the upper limits described above; or greater than or equal to any one of the lower limits described above and less than or equal to any one of the upper limits described above. When the size of the ion conductor dispersion particles in the ion conductor dispersion composition is within the above-described range, impregnation into the support is easy, and a high density on the surface of the polymer electrolyte membrane can be formed.

[0141] In addition, the ion conductor in the ion conductor dispersion composition may have a polydispersity index within a predetermined range. The closer the polydispersity index is to 1, the wider the size distribution of the dispersed particles is. As the polydispersity index approaches 1, Brownian motion occurs more slowly, thereby alleviating particle aggregation in the ion conductor dispersion composition, thereby increasing the stability and impregnation property of the ion conductor dispersion composition and increasing the mechanical strength of the polymer electrolyte membrane. The method for measuring the polydispersity index is according to the method described in the “Measurement of Dispersed Particle Size” section of Evaluation Example 3 below.

[0142] The lower limit of the polydispersity index may be about 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.6 or 1.65, and the upper limit may be about 1.5, 1.45, 1.4, 1.35, 1.3, 1.25, 1.2, 1.15, 1.1, 1.05, 1, 0.95, 0.9 or 0.85.

[0143] The polydispersity index may be greater than or equal to any one of the lower limits described above; less than or equal to any one of the upper limits described above; or greater than or equal to any one of the lower limits described above and less than or equal to any one of the upper limits described above. When the polydispersity index of the ion conductor in the ion conductor dispersion composition is within the above range, the stability, impregnation property, and mechanical strength of the polymer electrolyte membrane may be increased as described above.

[0144] The above ionic conductor dispersion composition may have a surface tension similar to or higher than that of a conventional chemical-based solvent. For example, the above ionic conductor dispersion composition may have a surface tension within a predetermined range. The method for measuring the surface tension is described in the "Surface Tension Evaluation" section of Evaluation Example 4 below.

[0145] The lower limit of the surface tension may be about 25 mN / m, 25.5 mN / m, 26 mN / m, 26.5 mN / m, 27 mN / m, 27.5 mN / m, 28 mN / m, 28.5 mN / m or 29 mN / m, and the upper limit is not specifically limited, but may be about 30 mN / m, 29.5 mN / m, 29 mN / m, 28.5 mN / m, 28 mN / m or 27.5 mN / m.

[0146] The surface tension may be greater than or equal to any one of the lower limits described above; less than or equal to any one of the upper limits described above; or greater than or equal to any one of the lower limits described above and less than or equal to any one of the upper limits described above. When the surface tension value of the ion conductor dispersion composition is within the above range, it can be uniformly dispersed within the polymer.

[0147] The fact that the surface tension is similar to or higher than that of a conventional chemical-based solvent is described in the “Surface Tension Evaluation” section of Evaluation Example 4, and the measurement results are shown in Table 8.

[0148]

[0149] 2. Method for manufacturing polymer electrolyte membrane

[0150] A method for manufacturing a polymer electrolyte membrane according to another embodiment of the present disclosure includes preparing a primary mixture by mixing an ion conductor with a solvent, preparing a secondary mixture by adding an environmentally friendly additive solvent to the primary mixture and mixing, preparing an ion conductor dispersion composition by adding a non-solvent to the secondary mixture and mixing, and preparing a polymer electrolyte membrane by coating the ion conductor dispersion composition on a substrate and then performing drying and heat treatment.

[0151] At this time, the environmentally friendly additive solvent satisfies each range of the dispersion term, polarity term, and hydrogen bond term of the Hansen solubility parameter as described above.

[0152] In addition, the specific types of the ion conductor, solvent and non-solvent are as described in “1. Ion conductor dispersion composition”.

[0153] The type of the substrate is not limited as long as it has a release property. For example, the substrate may be a polyethyleneterephtalate (PET) film, a cyclic olefin copolymer (COC) film, a polyacrylate (PAC) film, a polycarbonate (PC) film, a polyethylene (PE) film, a polymethylmethacrylate (PMMA) film, a polyetheretherketone (PEEK) film, a polyethylenenaphthalate (PEN) film, a polyetherimide (PEI) film, a polyimide (PI) film, a triacetylcellulose (TAC) film, or a combination thereof.

[0154] The above coating can be performed according to a known method. For example, the coating can be performed by electrospinning, direct casting, dip coating, spray coating, spin coating, die coating, roll coating, slot-die coating, bar coating, gravure coating, comma coating, curtain coating, or micro-gravure coating.

[0155] The above drying can be performed at a temperature within the range of 60°C to 120°C.

[0156] The above heat treatment can be appropriately controlled depending on the type of ion conductor included in the ion conductor dispersion composition.

[0157] For example, when a fluorine-based ion conductor is used, the process can be performed at a temperature in the range of 150°C to 220°C, and when a hydrocarbon-based ion conductor is used, the process can be performed at a temperature in the range of 80°C to 500°C.

[0158] The method for manufacturing the polymer electrolyte membrane may further include, after coating the ion conductor dispersion composition on the substrate, placing a porous support on the substrate coated with the ion conductor dispersion composition before drying and heat treatment, and then coating the ion conductor dispersion composition again on the porous support.

[0159] The polymer electrolyte membrane can also be manufactured as a reinforced membrane in which the ion conductor fills the pores of the porous support by placing the porous support and re-coating the ion conductor dispersion composition on the porous support.

[0160] The above porous support may be a fluorine-based support or a nano web support.

[0161] The fluorine-based support may correspond to, for example, expanded polytetrafluoroethylene (e-PTFE) having a microstructure of polymer fibrils or a microstructure in which nodes are interconnected by fibrils. In addition, a film having a microstructure of polymer fibrils without nodes may also be used as the porous support.

[0162] The above nano web support may be a support in which nano fibers are integrated in the form of a non-woven fabric containing a large number of pores.

[0163]

[0164] 3. Polymer electrolyte membrane

[0165] A polymer electrolyte membrane according to another embodiment of the present disclosure may include a porous support having porous pores, and an ion conductor filling the pores of the porous support.

[0166] The above porous support is as described in “2. Method for manufacturing a polymer electrolyte membrane.”

[0167] The above polymer electrolyte membrane can improve electrochemical and mechanical stability by being manufactured using the above-described ion conductor dispersion composition.

[0168] The polymer electrolyte membrane described above may have excellent transmittance. The transmittance may be expressed as total light transmittance (Tt). The method for measuring the transmittance follows the method described in the "Total Light Transmittance (Tt) and Transparency (haze) Evaluation" section of Evaluation Example 5 below.

[0169] For example, the total light transmittance (Tt) of the polymer electrolyte membrane may be within a predetermined range.

[0170] The lower limit of the above total light transmittance (Tt) may be about 90%, 90.2%, 90.4%, 90.6%, 90.8%, 91%, 91.2%, 91.4%, 91.6%, 91.8%, 92%, 92.2%, 92.4%, 92.6%, 92.8%, 93%, 93.2%, or 93.4%, and the upper limit may be about 100%, 99%, 98%, 97%, 96%, 95%, 94.5%, 94%, 93.5%, 93%, 92.5%, or 92%.

[0171] The total light transmittance (Tt) of the polymer electrolyte membrane may be equal to or greater than any one of the lower limits described above; equal to or less than any one of the upper limits described above; or equal to or greater than any one of the lower limits described above and equal to or less than any one of the upper limits described above. When the total light transmittance (Tt) of the polymer electrolyte membrane is within the above range, the degree of impregnation into the support may be excellent.

[0172] The transparency (haze) of the polymer electrolyte membrane is characterized by being 0.1% to 10%. The method for measuring the transparency is according to the method described in the “Total Light Transmittance (Tt) and Transparency (haze) Evaluation” section of Evaluation Example 5 below. For example, the lower limit of the haze may be about 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5%, 5.1%, 5.2%, 5.3% or 5.4%, and the upper limit may be about 10%, 9.5%, 9%, 8.5%, 8%, 7.5%, 7%, 6.5%, It could be 6%, 5.5%, 5.4%, 5.3%, 5.2%, 5.1%, 5%, 4.9%, 4.8%, 4.7%, 4.6%, 4.5%, 4.4%, 4.3%, or 4.2%.

[0173] The transparency (haze) of the polymer electrolyte membrane may be in a range of greater than or equal to any one of the lower limits described above; less than or equal to any one of the upper limits described above; or greater than or equal to any one of the lower limits described above and less than or equal to any one of the upper limits described above. When the transparency of the polymer electrolyte membrane is within the range, light scattering is reduced during formation of the polymer electrolyte membrane, so that a uniform polymer electrolyte membrane can be manufactured.

[0174] The fact that the above transparency (haze) shows a superior effect compared to that using a conventional chemical-based solvent is described in the “Total light transmittance (Tt) and transparency (haze) evaluation” section of Evaluation Example 5, and the measurement results accordingly are shown in Table 9.

[0175] In addition, the polymer electrolyte membrane can have excellent mechanical strength.

[0176] For example, the polymer electrolyte membrane may have a tensile strength in the longitudinal direction (MD) and a tensile strength in the transverse direction (TD) within a predetermined range. The method for measuring the tensile strength in the longitudinal direction (MD) and transverse direction (TD) is according to the method described in the “Measurement of Tensile Strength and Elongation” section of Evaluation Example 6 below.

[0177] The lower limit of the tensile strength in the longitudinal direction (MD) may be about 35 MPa, 36 MPa, 37 MPa, 38 MPa, 39 MPa, 40 MPa or 41 MPa, and the upper limit is not limited, but may be about 50 MPa, 49 MPa, 48 MPa, 47 MPa, 46 MPa, 45 MPa, 44 MPa, 43 MPa, 42 MPa, 41 MPa, 40 MPa, 39 MPa, 38 MPa, 37 MPa or 36 MPa.

[0178] The lower limit of the tensile strength in the transverse direction (TD) may be about 30 MPa, 30.5 MPa, 31 MPa, 31.5 MPa, 32 MPa, 32.5 MPa, 33 MPa, 33.5 MPa, 34 MPa, 34.5 MPa, 35 MPa or 35.5 MPa, and the upper limit may be, but is not limited to, about 40 MPa, 39 MPa, 38 MPa, 37 MPa, 36 MPa, 35 MPa, 34 MPa or 33 MPa.

[0179] The tensile strength in the longitudinal direction (MD) and the transverse direction (TD) may each be equal to or greater than any one of the lower limits described above; or may be equal to or greater than any one of the lower limits described above and equal to or less than any one of the upper limits described above. When the longitudinal tensile strength and the transverse tensile strength of the polymer electrolyte membrane are within the above ranges, both the planar direction and the thickness direction strength may be excellent.

[0180] In addition, the polymer electrolyte membrane may have an absolute value of the difference between the elongation in the longitudinal direction (MD) and the elongation in the transverse direction (TD) within a predetermined range. The smaller the absolute value of the difference between the elongation in the longitudinal direction (MD) and the elongation in the transverse direction (TD) of the polymer electrolyte membrane, the more isotropic it is. The more isotropic it is, the more the shape and dimensions of the polymer electrolyte membrane can be maintained under various loads and environmental conditions that occur during assembly of a water electrolysis cell, and the more durability can be improved. The method for measuring the elongation in the longitudinal direction (MD) and the elongation in the transverse direction (TD) follows the method described in the “Measurement of tensile strength and elongation” section of Evaluation Example 6 below.

[0181] The lower limit of the absolute value of the difference between the elongation in the longitudinal direction (MD) and the elongation in the transverse direction (TD) is not limited, but may be, for example, about 0%, 5%, 10%, 15% 20%, 30%, 40%, 50%, 60%, or 70%, and the upper limit may be about 50%, 45%, 40%, 35%, 30%, or 25%.

[0182] The absolute value of the difference between the elongation in the longitudinal direction (MD) and the elongation in the transverse direction (TD) may be less than or equal to any one of the upper limits described above; or may be greater than or equal to any one of the lower limits described above and less than or equal to any one of the upper limits described above. When the absolute value of the difference between the elongation in the longitudinal direction (MD) and the elongation in the transverse direction (TD) of the polymer electrolyte membrane is within the above range, the shape and dimensions of the polymer electrolyte membrane can be maintained under various loads and environmental conditions occurring during assembly of the electrolysis cell, and durability can be improved.

[0183] The polymer electrolyte membrane described above may exhibit superior wet expansion rates in the plane direction and thickness direction at room temperature and high temperature compared to those using conventional chemical-based solvents. The method for measuring the wet expansion rates in the plane direction and thickness direction is according to the method described in the "Wet Expansion Rate and Water Absorption Rate Measurement" section of Evaluation Example 7 below.

[0184] At this time, the room temperature may mean a temperature of 15°C to 25°C. For example, the lower limit of the room temperature may be 15°C, 16°C, 17°C, 18°C, 19°C, or 20°C, and the upper limit of the room temperature may be 25°C, 24°C, 23°C, 22°C, 21°C, or 20°C. The room temperature may mean a temperature that is equal to or greater than any one of the lower limits described above, and equal to or less than any one of the upper limits described above.

[0185] In addition, the high temperature may mean a temperature that is 75°C or higher. For example, the lower limit of the high temperature may be 75°C, 76°C, 77°C, 78°C, 79°C, or 80°C, and the upper limit of the high temperature may be, but is not limited to, for example, 100°C, 95°C, 90°C, or 85°C. The high temperature may mean a temperature that is equal to or greater than any one of the lower limits described above, or a temperature that is equal to or greater than any one of the lower limits described above, but equal to or less than any one of the upper limits described above.

[0186] The polymer electrolyte membrane may have a wet expansion coefficient in the plane direction measured at room temperature of 20% or less. As a preferred example, the wet expansion coefficient in the plane direction measured at room temperature may be measured at 20°C. For example, the lower limit of the wet expansion coefficient in the plane direction measured at room temperature may be, but is not limited to, about 13.5%, 14%, 14.5%, 15%, 15.5%, 16%, 16.5%, 17%, 17.5%, or 18%, and the upper limit may be about 20%, 19%, 18%, 17%, 16%, or 15.5%.

[0187] The surface direction wet expansion coefficient measured at the above room temperature may be equal to or greater than any one of the lower limits described above; or may be equal to or greater than any one of the lower limits described above and equal to or less than any one of the upper limits described above.

[0188] The polymer electrolyte membrane may have a wet expansion coefficient in the plane direction measured at the high temperature of 40% or less. As a preferred example, the wet expansion coefficient in the plane direction measured at the high temperature may be measured at 80°C. For example, the lower limit of the wet expansion coefficient in the plane direction measured at the high temperature may be, but is not limited to, about 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, or 38.5%, and the upper limit may be about 40%, 39%, 38%, 37%, 36%, or 35%.

[0189] The surface direction wet expansion coefficient measured at the above high temperature may be equal to or greater than any one of the lower limits described above; or may be equal to or greater than any one of the lower limits described above and equal to or less than any one of the upper limits described above. When the surface direction wet expansion coefficient measured at the above high temperature is within the above range, the shape of the polymer electrolyte membrane and the electrode positioned on the polymer electrolyte membrane can be maintained even when water electrolysis is performed, and durability can be improved.

[0190] The polymer electrolyte membrane may have a thickness direction wet expansion ratio of 30% or less as measured at room temperature. As a preferred example, the thickness direction wet expansion ratio measured at room temperature may be measured at 20°C. For example, the lower limit of the thickness direction wet expansion ratio measured at room temperature may be, but is not limited to, 20% or more, and the upper limit may be, for example, 25%, 24%, 23%, 22%, 21%, or 20%.

[0191] The thickness direction wet expansion coefficient measured at the above room temperature may be equal to or greater than any one of the lower limits described above; or may be equal to or greater than any one of the lower limits described above and equal to or less than any one of the upper limits described above.

[0192] The polymer electrolyte membrane may have a thickness direction wet expansion ratio measured at a high temperature of 50% or less. As a preferred example, the thickness direction wet expansion ratio measured at the high temperature may be measured at 80°C. For example, the lower limit of the thickness direction wet expansion ratio measured at the high temperature may be, but is not limited to, about 20%, 23%, 30%, 32%, 40%, 42%, 43%, or 49%, and the upper limit may be about 60%, 50%, 49%, 44%, 43%, 33%, 31%, 30%, or 24%.

[0193] The thickness direction wet expansion coefficient measured at the above high temperature may be equal to or greater than any one of the lower limits described above; or may be equal to or greater than any one of the lower limits described above and equal to or less than any one of the upper limits described above. When the thickness direction wet expansion coefficient measured at the above high temperature is within the above range, the shape of the polymer electrolyte membrane and the electrode positioned on the polymer electrolyte membrane can be maintained even when water electrolysis is performed, and durability can be improved.

[0194] The polymer electrolyte membrane may exhibit excellent moisture absorption at room temperature and high temperature. The moisture absorption rate can be measured according to the method described in the "Wet Expansion Rate and Water Absorption Rate Measurement" section of Evaluation Example 7 below. The temperature ranges at room temperature and high temperature are as described in the wet expansion rates in the plane direction and thickness direction.

[0195] For example, the polymer electrolyte membrane may have a water absorption rate measured at room temperature within a predetermined range. As a preferred example, the water absorption rate measured at room temperature may be measured at 20°C.

[0196] The lower limit of the above moisture absorption rate may be about 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 35% or 40%, and the upper limit is not limited, but may be about 50%, 49%, 48%, 47%, 46%, 45%, 44%, 43%, 40%, 35% or 30%.

[0197] The moisture absorption rate measured at the above room temperature may be equal to or greater than any one of the lower limits described above; or may be equal to or greater than any one of the lower limits described above and equal to or less than any one of the upper limits described above.

[0198] Additionally, the polymer electrolyte membrane may have a moisture absorption rate measured at a high temperature within a predetermined range. As a preferred example, the moisture absorption rate measured at a high temperature may be measured at 80°C.

[0199] The lower limit of the above moisture absorption rate may be about 20%, 25%, 30%, 35%, 40%, 45% or 50%, and the upper limit is not limited, but may be about 60%, 55%, 50% or 45%.

[0200] The moisture absorption rate measured at the above high temperature may be equal to or greater than any one of the lower limits described above; or may be equal to or greater than any one of the lower limits described above and equal to or less than any one of the upper limits described above.

[0201] In addition, the polymer electrolyte membrane may have planar and thickness-wise hydrogen ion conductivities that are equivalent to or superior to those of polymer electrolyte membranes using conventional chemical-based solvents. The method for measuring the planar and thickness-wise hydrogen ion conductivities is according to the method described in the “Measurement of Hydrogen Ion Conductivity” section of Evaluation Example 8 below. The planar and thickness-wise hydrogen ion conductivities may be measured at four different temperatures. For example, they may be measured at a first temperature, a second temperature, a third temperature, and a fourth temperature, respectively.

[0202] The first temperature may be a temperature within a range of 15°C to 25°C. For example, the lower limit of the first temperature may be 15°C, 16°C, 17°C, 18°C, 19°C, or 20°C, and the upper limit of the first temperature may be 25°C, 24°C, 23°C, 22°C, 21°C, or 20°C. The first temperature may be a temperature that is equal to or greater than any one of the lower limits described above, and equal to or less than any one of the upper limits described above.

[0203] The second temperature may be a temperature within a range of 35°C to 45°C. For example, the lower limit of the second temperature may be 35°C, 36°C, 37°C, 38°C, 39°C, or 40°C, and the upper limit of the second temperature may be 45°C, 44°C, 43°C, 42°C, 41°C, or 40°C. The second temperature may be a temperature that is equal to or greater than any one of the lower limits described above, and equal to or less than any one of the upper limits described above.

[0204] The third temperature may be a temperature within a range of 55°C to 65°C. For example, the lower limit of the third temperature may be 55°C, 56°C, 57°C, 58°C, 59°C, or 50°C, and the upper limit of the third temperature may be 55°C, 54°C, 53°C, 52°C, 51°C, or 50°C. The third temperature may be a temperature that is equal to or greater than any one of the lower limits described above, and equal to or less than any one of the upper limits described above.

[0205] The fourth temperature may be a temperature within a range of 75°C to 85°C. For example, the lower limit of the fourth temperature may be 75°C, 76°C, 77°C, 78°C, 79°C, or 80°C, and the upper limit of the fourth temperature may be 85°C, 84°C, 83°C, 82°C, 81°C, or 80°C. The fourth temperature may be a temperature that is equal to or greater than any one of the lower limits described above, and equal to or less than any one of the upper limits described above.

[0206] The above polymer electrolyte membrane may have surface and thickness direction hydrogen ion conductivities measured at a first temperature and under conditions of immersion in water, each within a predetermined range. As a preferred example, the hydrogen ion conductivity measured at the first temperature may be that measured at 20°C.

[0207] For example, the lower limit of the surface direction and thickness direction hydrogen ion conductivity measured under the first temperature, water immersion condition may be about 0.05 S / cm, 0.06 S / cm, 0.07 S / cm, 0.08 S / cm, 0.09 S / cm, 0.1 S / cm, 0.11 S / cm, 0.12 S / cm, 0.13 S / cm, 0.14 S / cm or 0.15 S / cm, and the upper limit is not limited, but may be about 0.2 S / cm, 0.19 S / cm, 0.18 S / cm, 0.17 S / cm, 0.16 S / cm, 0.15 S / cm, 0.14 S / cm, 0.13 S / cm, 0.12 S / cm, 0.11 S / cm or 0.1 S / cm. there is.

[0208] The above polymer electrolyte membrane may have surface and thickness direction hydrogen ion conductivities measured at a second temperature and under conditions of immersion in water, each within a predetermined range. As a preferred example, the hydrogen ion conductivity measured at the second temperature may be that measured at 40°C.

[0209] For example, the lower limit of the surface direction and thickness direction hydrogen ion conductivity measured under the second temperature, water immersion condition may be about 0.1 S / cm, 0.12 S / cm, 0.13 S / cm, 0.14 S / cm or 0.15 S / cm, and the upper limit is not limited, but may be, for example, about 0.3 S / cm, 0.25 S / cm, 0.2 S / cm, 0.19 S / cm, 0.18 S / cm, 0.17 S / cm, 0.16 S / cm, 0.15 S / cm or 0.14 S / cm.

[0210] The above polymer electrolyte membrane may have a hydrogen ion conductivity in the plane direction and in the thickness direction, measured under conditions of immersion in water at a third temperature, each within a predetermined range. As a preferred example, the hydrogen ion conductivity measured at the third temperature may be that measured at 60°C.

[0211] For example, the lower limit of the surface direction and thickness direction hydrogen ion conductivity measured under the third temperature, water immersion condition may be about 0.15 S / cm, 0.16 S / cm, 0.17 S / cm, 0.18 S / cm, 0.19 S / cm, 0.2 S / cm, 0.21 S / cm, 0.22 S / cm, 0.23 S / cm, 0.24 S / cm or 0.25 S / cm, and the upper limit may be, but is not limited to, about 0.4 S / cm, 0.35 S / cm, 0.3 S / cm, 0.25 S / cm, 0.2 S / cm or 0.19 S / cm.

[0212] The above polymer electrolyte membrane may have a hydrogen ion conductivity in the plane direction and in the thickness direction, measured at a fourth temperature and under conditions of immersion in water, each within a predetermined range. As a preferred example, the hydrogen ion conductivity measured at the fourth temperature may be that measured at 80°C.

[0213] For example, the lower limit of the surface direction and thickness direction hydrogen ion conductivity measured under the above-mentioned fourth temperature, water immersion condition may be about 0.2 S / cm, 0.21 S / cm, 0.22 S / cm, 0.23 S / cm, 0.24 S / cm, 0.25 S / cm, 0.26 S / cm, 0.27 S / cm, 0.28 S / cm, 0.29 S / cm, 0.3 S / cm, 0.31 S / cm, 0.32 S / cm, 0.33 S / cm, 0.34 S / cm, 0.35 S / cm, 0.36 S / cm or 0.37 S / cm, and the upper limit is not limited, but may be about 0.5 S / cm, 0.45 S / cm, 0.4 S / cm, 0.35 S / cm, 0.3 S / cm Or it could be around 0.25 S / cm.

[0214] The surface direction and thickness direction hydrogen ion conductivities measured at each of the first temperature, second temperature, third temperature, and fourth temperature and under conditions of immersion in water may each have a range that is equal to or greater than any one of the lower limits described above; or equal to or greater than any one of the lower limits described above, and equal to or less than any one of the upper limits described above.

[0215] The polymer electrolyte membrane may have surface and thickness direction hydrogen ion conductivities within the above ranges measured at the first, second, third, and fourth temperatures, even when an eco-friendly additive solvent is used instead of the existing chemical-based solvent, and thus the hydrogen ion conductivity may be equivalent to or superior to that of the membrane-electrode assembly when the existing chemical-based solvent is used. By having surface direction ion conductivity within the above-described range, the polymer electrolyte membrane may improve the ion transfer capability of the membrane-electrode assembly.

[0216] Additionally, the density of the polymer electrolyte membrane is 1.85 g / cm 3 2.5 g / cm 3 It can be, for example, 1.85 g / cm 3 2 g / cm 3 , or 1.9 g / cm 3 2 g / cm 3 This may be. The method for measuring the density is according to the method described in the "Density Evaluation" section of Evaluation Example 9 below. In a polymer electrolyte membrane of the same thickness, a higher density indicates higher impregnation and a higher mass transfer diffusion coefficient, which is advantageous. The density of the polymer electrolyte membrane may be higher compared to that of a membrane using a conventional chemical-based solvent.

[0217] The surface direction compressive resistance of the polymer electrolyte membrane may be 35 N or more, for example, 35 N to 50 N, or 35 N to 48 N. The method for measuring the surface direction compressive resistance is according to the method described in the “measurement of surface direction compressive resistance” item of Evaluation Example 10 below. The polymer electrolyte membrane has a surface direction compressive resistance value within the above-described range, so that the shape of the polymer electrolyte membrane can be maintained under a load received during cell fastening, compared to a polymer electrolyte membrane using an existing chemical-based solvent.

[0218] These polymer electrolyte membranes can be applied to polymer electrolyte membrane fuel cells and polymer electrolyte membrane water electrolysis cells.

[0219]

[0220] 4. 1. Membrane-electrode assembly and electrochemical cell

[0221] A membrane-electrode assembly according to another embodiment of the present disclosure comprises: the polymer electrolyte membrane; a hydrogen electrode positioned on one side of the polymer electrolyte membrane; and an air electrode positioned on the other side of the polymer electrolyte membrane.

[0222] The above membrane-electrode assembly can be applied to a fuel cell or a water electrolysis cell.

[0223] When the above membrane-electrode assembly is applied to a fuel cell, the hydrogen electrode means an electrode that supplies hydrogen gas (fuel), and the air electrode means an electrode that supplies air and generates water.

[0224] Since known materials can be used for the hydrogen electrode and air electrode when the above membrane-electrode assembly is applied to a fuel cell, a detailed description of the relevant parts is omitted.

[0225] Meanwhile, when the membrane-electrode assembly is applied to a water electrolysis cell, the air electrode means an electrode that supplies water (fuel) and generates oxygen gas, and the hydrogen electrode means an electrode that generates hydrogen gas.

[0226] The hydrogen electrode and air electrode when the above membrane-electrode assembly is applied to a water electrolysis cell are described below.

[0227] The above air electrode is an electrode where the oxygen evolution reaction (OER) occurs.

[0228] The above hydrogen electrode may include a catalyst layer for the hydrogen electrode.

[0229] The above hydrogen electrode catalyst layer may include a precious metal oxide.

[0230] The above precious metal oxide may be iridium oxide, an oxide of an iridium alloy, or a combination thereof.

[0231] For example, the noble metal oxide is IrO x (where x is an integer from 1 to 3), IrMO x (wherein M includes Ru, Pt, Sn, Se, Zn, Au, Te, Nb, or a combination thereof, and x is an integer from 1 to 3) or a combination thereof.

[0232] In addition, the catalyst layer for the hydrogen electrode may further include a carrier that supports a precious metal oxide.

[0233] The above carrier is not limited in type as long as it is a carrier that is usually applied to support a precious metal oxide, and may be, for example, titanium dioxide (TiO2).

[0234] The above hydrogen electrode may further include an ion conductor to improve the adhesion of the catalyst layer and to transfer hydrogen ions.

[0235] The above ion conductor is as described in the “1. Ion conductor dispersion composition” section.

[0236] The ion conductor included in the above hydrogen electrode and the ion conductor included in the polymer electrolyte membrane may be the same or different.

[0237] The above hydrogen electrode is an electrode where the hydrogen evolution reaction (HER) occurs.

[0238] The above air electrode may include a catalyst layer for the air electrode.

[0239] The above catalyst layer for the air electrode is different from the catalyst layer for the hydrogen electrode.

[0240] The above-mentioned catalyst layer for the air electrode may include active particles.

[0241] The above active particles may include a precious metal, and the precious metal may be a platinum-based precious metal.

[0242] The platinum-based precious metal may be platinum (Pt) and / or a Pt-M alloy. The M may be palladium (Pd), ruthenium (Ru), iridium (Ir), osmium (Os), gallium (Ga), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), silver (Ag), gold (Au), zinc (Zn), tin (Sn), molybdenum (Mo), tungsten (W), lanthanum (La), or rhodium (Rh).

[0243] Specifically, the Pt-M alloy includes Pt-Pd, Pt-Sn, Pt-Mo, Pt-Cr, Pt-W, Pt-Ru, Pt-Ni, Pt-Co, Pt-Y, Pt-Ru-W, Pt-Ru-Ni, Pt-Ru-Mo, Pt-Ru-Rh-Ni, Pt-Ru-Sn-W, Pt-Ru-Ir-Ni, Pt-Co-Mn, Pt-Co-Ni, Pt-Co-Fe, Pt-Co-Ir, Pt-Co-S, Pt-Co-P, Pt-Fe, Pt-Fe-Ir, Pt-Fe-S, Pt-Fe-P, Pt-Au-Co, Pt-Au-Fe, Pt-Au-Ni, Pt-Ni, Pt-Ni-Ir, Pt-Cr, Pt-Cr-Ir, or these Mixtures can be used.

[0244] The above-mentioned catalyst layer for the air electrode may further include a carrier that supports the active particles.

[0245] The above carrier may be different from the carrier applied to the catalyst layer of the above hydrogen electrode.

[0246] For example, the carrier may be a carbon-based carrier.

[0247] The carbon-based carrier may be graphite, super P, carbon fiber, carbon sheet, carbon black, Ketjen Black, Denka black, acetylene black, carbon nanotube (CNT), carbon sphere, carbon ribbon, fullerene, activated carbon, carbon nanofiber, carbon nanowire, carbon nanoball, carbon nanohorn, carbon nanocage, carbon nanoring, ordered nano- / meso-porous carbon, carbon aerogel, mesoporous carbon, graphene, stabilized carbon, activated carbon, or a combination thereof.

[0248] The above-mentioned hydrogen electrode and air electrode may include only the hydrogen electrode catalyst layer and the air electrode catalyst layer, but may include an electrode substrate together with the catalyst layer.

[0249] The above electrode substrate can serve to support the electrode and diffuse the fuel and oxidant to the catalyst layers for the hydrogen electrode and the air electrode.

[0250] The electrode substrate may include a microporous layer, a porous diffusion layer, or a combination thereof.

[0251] The above microporous layer serves to enhance the diffusion effect of the reactant, and may generally include a conductive powder having a small particle size, for example, carbon powder, carbon black, acetylene black, activated carbon, metal oxide nanowires, carbon fibers, fullerene, carbon nanotubes, carbon nanowires, carbon nano-horns, or carbon nano rings.

[0252] The above porous diffusion layer is made of porous titanium, carbon paper, carbon cloth, carbon felt or metal cloth (a porous film made of metal cloth in a fibrous state or a metal film formed on the surface of a cloth formed of polymer fibers).

[0253] The above microporous layer and the above porous diffusion layer may include known materials in addition to those exemplified above.

[0254] The above electrode substrate can be treated with a water-repellent fluorine resin, in which case the diffusion efficiency of reactants can be prevented from being reduced by water generated during operation of the electrolysis cell.

[0255] As the above fluorine-based resin, polytetrafluoroethylene, polyvinylidene fluoride, polyhexafluoropropylene, polyperfluoroalkyl vinyl ether, polyperfluorosulfonyl fluoride, alkoxy vinyl ether, fluorinated ethylene propylene, polychlorotrifluoroethylene or a copolymer thereof can be used.

[0256] An electrochemical cell according to another embodiment of the present disclosure includes the membrane-electrode assembly.

[0257] The above electrochemical cell may be a fuel cell or a water electrolysis cell, and other configurations included in the fuel cell and water electrolysis cell other than the configuration described above may use known configurations.

[0258] Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement them. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0259]

[0260] Manufacturing Example 1. Ionic Conductor Dispersion Composition

[0261] Water was added to the reaction vessel, and PFSA polymer (Solvay, Aquivion) ​​as an ion conductor was added to the water and mixed using an orbital shaker to prepare a primary mixture.

[0262] A hydrophilic, environmentally friendly additive solvent or chemical-based solvent was added to the above primary mixture as described in Table 2 below, and mixed using a resonance acoustic mixer to prepare a secondary mixture.

[0263] A non-solvent was added to the above secondary mixture and mixed using a resonant acoustic mixer to prepare a tertiary mixture.

[0264] The above tertiary mixture was placed in an orbital shaker to remove primary bubbles, and stored at about 5°C for about 3 to 15 days to remove secondary bubbles, thereby preparing an ion conductor dispersion composition.

[0265] According to the above Manufacturing Example 1, ion conductor dispersion compositions of Manufacturing Examples 1 to 6 and Manufacturing Comparative Examples 1 and 2 were manufactured as shown in Table 2 below.

[0266]

[0267] Manufacturing Example 1 Manufacturing Example 2 Manufacturing Example 3 Manufacturing Example 4 Manufacturing Example 5 Manufacturing Example 6 Manufacturing Comparative Example 1 Manufacturing Comparative Example 2 Ion Conductor (PFSA) 25 25 25 25 25 25 20 Water 47.25 42 36.75 47.25 42 36.75 34.6 15 5 2.3 Eco-friendly Additive Solvent GBL 1) 5.2510.515.75-----ML 2) ---5.2510.515.75--Chemical-based solvent (NMP) 3) )------9.616-Nonsolvent (nPA) 4) )22.522.522.522.522.522.530.76927.7

[0268] 1) GBL: gamma butyrolactone (Sigma-Aldrich, ≥99%) 2) ML: methyl L-lactate (Sigma-Aldrich, 98%)

[0269] 3) NMP: N-methyl-2-pyrrolidone (FUJIFILM Wako Chemical, Duper Dehydrated)

[0270] 4) nPA: Propyl alcohol (Daejung Chemical Co., Ltd., 99.5%)

[0271]

[0272] At this time, the unique Hansen solubility parameters of the ion conductor, water, eco-friendly additive solvent, chemical-based solvent and nonsolvent according to the Hansen solubility parameter estimation value at 25℃ by the computer software HANSEN SOLUBILITY PARAMETERS IN PRACTICE (HSPiP) VER 5.2.06 and SMILES of the software ChemDraw (a function for estimating Hansen solubility parameters from the molecular structure of the solvent) are as shown in Table 3 below.

[0273] Hansen solubility parameter pKaδ d (MPa 0.5 )δ p (MPa 0.5 )δ h (MPa 0.5)Ion conductor-14.910.211.8Water14.015.516.042.3Gamma-butyrolactone4.518.016.67.4Methyl L-lactate3.815.86.510.2N-methyl-2-pyrrolidone7.818.012.37.2Propyl alcohol16.516.06.817.4

[0274] First, the Hansen solubility parameters of the mixture were calculated using the dispersion term, polarity term, and hydrogen bonding term of the Hansen solubility parameters of the mixture according to the weight ratio using the Hansen solubility parameters of each component included in the mixture in Table 3, using the following mathematical equations 2-1 to 2-3. The results are shown in Table 4.

[0275] [Equation 2-1]

[0276]

[0277] [Equation 2-2]

[0278]

[0279] [Equation 2-3]

[0280]

[0281] In mathematical expressions 2-1 to 2-3, δ d2 is the dispersion term of the mixture, and δ p2 is the polar term of the mixture, and δ h2 is the hydrogen bonding term of the mixture, w1 is the weight of the solvent, w2 is the weight of the eco-friendly additive solvent, w3 is the weight of the non-solvent, and δ d,1 , δ p,1 , δ h,1 are the dispersion term, polarity term, and hydrogen bonding term of the Hansen solubility parameter of the solvent, respectively, and δ d,2 , δ p,2 , δ h,2 are the dispersion term, polarity term, and hydrogen bonding term of the Hansen solubility parameter of the eco-friendly additive solvent, and δ d,3 , δ p,3 , δ h,3 are the dispersion term, polarity term, and hydrogen bonding term of the Hansen solubility parameter of the non-solvent.

[0282] Next, the Hansen solubility parameters of the ion conductor in Table 3 and the Hansen solubility parameters of the mixture in Table 4 are substituted into the following mathematical expression 1 to obtain the distance (R) between the Hansen solubility parameters of the ion conductor and the Hansen solubility parameters of the mixture. a ) was calculated. The results are shown in Table 4 below.

[0283] [Mathematical Formula 1]

[0284]

[0285] In the above mathematical expression 1, the δ d1 (Unit: MPa 0.5 ) is the dispersion term of the ionic conductor, and the δ d2 (Unit: MPa 0.5 ) is the dispersion term of the above mixture, and the above δ p1 (Unit: MPa 0.5 ) is the polarity term of the ionic conductor, and the δ p2 (Unit: MPa 0.5 ) is the polarity term of the above mixture, and the above δ h1 (Unit: MPa 0.5 ) is the hydrogen bonding term of the ion conductor, and the δ h2 (Unit: MPa 0.5 ) is the hydrogen bonding term of the above mixture.

[0286]

[0287] The distance between the Hansen solubility parameter of the ionic conductor and the Hansen solubility parameter of the mixture (R a )δ d2 (MPa 0.5 )δ p2 (MPa 0.5 )δ h2 (MPa 0.5) Manufacturing Example 115.8313.2832.3920.90 Manufacturing Example 216.0013.3229.9418.54 Manufacturing Example 316.1813.3727.5016.22 Manufacturing Example 415.6712.5832.5820.98 Manufacturing Example 515.6911.9130.3418.68 Manufacturing Example 615.7111.2528.0916.40 Comparative Example 116.0312.6829.4918.00 Comparative Example 215.6712.8233.6822.09

[0288] Example 1.

[0289] After fixing a polyimide film (PI Advanced Materials Co., Ltd., GF300) on a glass plate, the ion conductor dispersion composition manufactured according to Manufacturing Example 1 was first coated using a direct casting method.

[0290] After placing an expanded-polytetrafluoroethylene (e-PTFE) support having a porosity of about 87% on the first-coated polyimide film, the ion conductor dispersion composition was secondarily coated using a direct casting method.

[0291] A polymer electrolyte membrane was manufactured by drying in an oven at 60℃, 80℃, 100℃, and 120℃ in that order, and then heat-treating at a temperature in the range of 200℃ to 220℃ for 5 to 10 minutes.

[0292]

[0293] Example 2.

[0294] A polymer electrolyte membrane was manufactured in the same manner as in Example 1, except that the ion conductor dispersion composition manufactured according to Manufacturing Example 2 was used instead of the ion conductor dispersion composition manufactured according to Manufacturing Example 1.

[0295]

[0296] Example 3.

[0297] A polymer electrolyte membrane was manufactured in the same manner as in Example 1, except that the ion conductor dispersion composition manufactured according to Manufacturing Example 3 was used instead of the ion conductor dispersion composition manufactured according to Manufacturing Example 1.

[0298]

[0299] Example 4.

[0300] A polymer electrolyte membrane was manufactured in the same manner as in Example 1, except that the ion conductor dispersion composition manufactured according to Manufacturing Example 4 was used instead of the ion conductor dispersion composition manufactured according to Manufacturing Example 1.

[0301]

[0302] Example 5.

[0303] A polymer electrolyte membrane was manufactured in the same manner as in Example 1, except that the ion conductor dispersion composition manufactured according to Manufacturing Example 5 was used instead of the ion conductor dispersion composition manufactured according to Manufacturing Example 1.

[0304]

[0305] Example 6.

[0306] A polymer electrolyte membrane was manufactured in the same manner as in Example 1, except that the ion conductor dispersion composition manufactured according to Manufacturing Example 6 was used instead of the ion conductor dispersion composition manufactured according to Manufacturing Example 1.

[0307]

[0308] Comparative Example 1.

[0309] A polymer electrolyte membrane was manufactured in the same manner as in Example 1, except that the ion conductor dispersion composition manufactured according to Comparative Manufacturing Example 1 was used instead of the ion conductor dispersion composition manufactured according to Manufacturing Example 1.

[0310]

[0311] Comparative Example 2.

[0312] A polymer electrolyte membrane was manufactured in the same manner as in Example 1, except that the ion conductor dispersion composition manufactured according to Comparative Manufacturing Example 2 was used instead of the ion conductor dispersion composition manufactured according to Manufacturing Example 1.

[0313]

[0314] Evaluation Example 1. Viscosity Measurement

[0315] The viscosity of the ion conductor dispersion compositions according to the above Manufacturing Examples 1 to 6 and Comparative Examples 1 to 2 was measured as follows.

[0316] The viscosity of the ion conductor dispersion compositions of the above manufacturing examples and comparative examples was measured at 25°C using a flow sweep measurement protocol using rheometer equipment.

[0317] The results of viscosity measured according to the above method are shown in Table 5 below.

[0318]

[0319] Viscosity (cP) Manufacturing Example 1 247.81 Manufacturing Example 2 247.23 Manufacturing Example 3 247.56 Manufacturing Example 4 598.9 Manufacturing Example 5 663.49 Manufacturing Example 6 1066.69 Comparative Example 1 102.4 Comparative Example 2 438.4

[0320] Evaluation Example 2. Contact angle measurement of ion conductor dispersion composition on support

[0321] The contact angle of the ion conductor dispersion composition on the support according to the above manufacturing examples 1 to 6 was measured as follows.

[0322] A support was fixed on a glass plate, and the ion conductor dispersion composition according to Manufacturing Examples 1 to 6 was dropped onto the support every 0.206 seconds using a contact angle device (KRUSS, DSA100), and a photograph of the ion conductor dispersion composition on the support was captured.

[0323] The contact angle on the support was measured when the ion conductor dispersion composition was dropped on the support for the first time (0 seconds) and the 200th time (41.2 seconds), and the rate of change in the contact angle on the support was calculated according to Equation 1 below. The results at this time are shown in Table 6 below.

[0324] [Formula 1]

[0325] Rate of change in contact angle of ionic conductor dispersion composition on support = (ab) / a 100

[0326] In Equation 1, a is the contact angle with respect to the support when the ion conductor dispersion composition is dropped on the support for the first time, and b is the contact angle with respect to the support when the ion conductor dispersion composition is dropped on the support for the 200th time.

[0327] The change in the contact angle of the ionic conductor dispersion composition for the support is expressed rounded to the third decimal place.

[0328]

[0329] Contact angle on support (°) Change rate of contact angle on support (%) 1st 200th Manufacturing example 1 105.45 2.94 9.81 Manufacturing example 2 104.95 745.66 Manufacturing example 3 91.26 034.21 Manufacturing example 4 112.14 7.95 7.27 Manufacturing example 5 111.54 8.95 6.14 Manufacturing example 6 118.44 9.15 8.53 Comparative example 197.25 5.54 2.90 Comparative example 2 106.95 0.35 2.95

[0330] Evaluation Example 3. Measurement of dispersed particle size and polydispersity index

[0331] The particle size and polydispersity index of the ion conductor dispersion compositions according to Manufacturing Examples 1 to 6 and Comparative Examples 1 to 2 were measured as follows.

[0332] The particle size and polydispersity index of the ion conductor dispersion in the composition were measured by diluting it with n-propyl alcohol at 25°C using the dynamic light scattering method using particle characterization equipment (Otsuka, EKSZ-20000S).

[0333] The results at this time are shown in Table 7 below.

[0334]

[0335] Dispersion Particle Size (nm) Polydispersity Index (PDI) Manufacturing Example 1 8 27.10.9 17 Manufacturing Example 2 10 32.11.131 Manufacturing Example 3 14 22.21.355 Manufacturing Example 4 9 59.40.975 Manufacturing Example 5 8 43.70.940 Manufacturing Example 6 7 29.40.832 Comparative Example 1 24 27.32.119 Comparative Example 2 10 11.50.922

[0336] Evaluation Example 4. Surface Tension Evaluation

[0337] The surface tension of the ion conductor dispersion compositions according to Manufacturing Examples 1 to 6 and Comparative Examples 1 to 2 was measured as follows.

[0338] Measurements were made using the K20 equipment from KRUSS at a measurement temperature of 25℃ according to the Du Nouy Ring Method, and the results are shown in Table 8 below.

[0339] Surface tension (mN / m) Manufacturing Example 1 28.12 Manufacturing Example 2 28.76 Manufacturing Example 3 29.02 Manufacturing Example 4 27.20 Manufacturing Example 5 27.61 Manufacturing Example 6 28.17 Comparative Example 127.65 Comparative Example 226.19

[0340] Evaluation Example 5. Evaluation of total light transmittance (Tt) and transparency (haze)

[0341] The total light transmittance (Tt) and transparency (haze) of the polymer electrolyte membranes manufactured according to Examples 1 to 6 and Comparative Examples 1 to 2 were measured as follows.

[0342] Using a haze meter, 25 cm 2 The results of measuring the total light transmittance (T,t), haze, and parallel transmittance of the transmitted light passing through the polymer electrolyte membrane using an integrating sphere are shown in Table 9 below.

[0343]

[0344] Total Light Transmittance (Tt) Transparency (%) Example 193.5 4.4 Example 292.1 4.8 Example 392.3 5.4 Example 491.9 4.2 Example 592.6 4.2 Example 692.6 4.3 Comparative Example 193.5 13.7 Comparative Example 292.0 17.4

[0345] Evaluation Example 6. Measurement of tensile strength and elongation

[0346] The tensile strength and elongation of the polymer electrolyte membranes manufactured according to Examples 1 to 6 and Comparative Examples 1 to 2 were measured as follows.

[0347] The above tensile strength and tensile elongation were measured by pulling in the longitudinal direction (MD) and transverse direction (TD) using an Instron6800 series device at a test speed (crosshead speed) of 50 mm / min using a 1 kN load cell for a polymer electrolyte membrane with an area of ​​10 ㎠.

[0348] The results at this time are shown in Table 10 below.

[0349] Tensile strength (MPa) Elongation (%) MDT DMDT Absolute value of difference in elongation between D and TD Example 1 41.8 38.0 1 21.37 5.1 46.2 Example 2 42.5 42.9 1 17.4 9 4.4 23 Example 3 40.3 38.5 1 20.5 9 4.4 26.1 Example 4 36 34.7 5 2 36.5 3 162.2 5 7 4.28 Example 5 39.3 33 32.6 6 2 20.74 168.4 8 5 2.26 Example 6 41.67 35.6 2 33.7 4 194.5 2 39.22 Comparative Example 1 33.9 32.4 1 35.17 7.6 5 7.46 Comparative Example 2 25.5 2 8.3 1 64.4 9 0.37 4.1

[0350] Evaluation Example 7. Measurement of wet swelling rate and water absorption rate

[0351] The wet swelling rate and water absorption rate of the polymer electrolyte membranes manufactured according to Examples 1 to 6 and Comparative Examples 1 to 2 were measured as follows.

[0352] After drying the polymer electrolyte membrane in a vacuum oven at 80°C for 24 hours, the weight of the membrane (W dry ) and the length (L) in the in-plane (IP) and through-plane (TP) directions dry,IP, L dry,TP ) is measured. After that, the membrane is immersed in ultrapure water at room temperature for 24 hours, then taken out again and the water on the surface is immediately removed, and the weight of the membrane (W wet ) and length (L) in the surface direction (IP) and thickness direction (TP) wet,IP, L wet, TP ) are measured. The swelling ratio and water uptake in the surface direction and thickness direction according to the above method at 20℃ and 80℃ are calculated using the following equations 2 to 4, respectively. The results at this time are shown in Table 11 below.

[0353] [Formula 2]

[0354] Wet swelling ratio in the direction of the surface (IP) (%) = (L wet,IP -L dry,IP ) / L dry,IP 100

[0355] [Formula 3]

[0356] Wet swelling ratio in the thickness direction (TP) (%) = (L wet,TP -L dry,TP ) / L dry,TP 100

[0357] [Formula 4]

[0358] Moisture absorption rate (%) = (W wet -W dry ) / W dry 100

[0359]

[0360] 20℃80℃Wet expansion rate(%)Moisture absorption rate(%)Wet expansion rate(%)Moisture absorption rate(%)IPTPIPTPExample 118.3224.6532.7330.9523.8141.43Example 217.6425.7131.6135.1830.4642.88Example 317.0826.0129.3938.7632.1143.83Example 415.5323.4043.3938 .9443.7850.08Example 515.4622.3729.7935.8542.3250.05Example 615.0921.0328.3135.4642.0547.19Comparative Example 19.723.4426.8628.7349.2953.40Comparative Example 213.1124.729.3237.5861.3765.18

[0361] Evaluation Example 8. Measurement of hydrogen ion conductivity

[0362] The surface-wise hydrogen ion conductivity of the polymer electrolyte membranes manufactured according to Examples 1 to 6 and Comparative Examples 1 to 2 was measured as follows.

[0363] The in-plane ion-conductivity in the above-mentioned plane and thickness directions was measured using a 1225B Frequency Response Analyzer (Solartron) at temperatures of 20°C, 40°C, 60°C, and 80°C and when immersed in water. The membrane resistance at temperatures of 20°C, 40°C, 60°C, and 80°C was used to calculate the in-plane ion-conductivity using the following equation. The effective area of ​​the membrane was 1 cm. 2 It was.

[0364] The results at this time are shown in Table 12 below.

[0365] Surface direction hydrogen ion conductivity (S / cm)Thickness direction hydrogen ion conductivity (S / cm)20℃40℃60℃80℃20℃40℃60℃80℃Example 10.0800.1330.1660.2150.0990.1390.1900.243Example 20.1160.1700.2250.2890.1280.1830.2390.299Example 30.1510.1970.2840.3770.1650.2190.3250.407Example 40.1190.1640.2310.2970.1 280.1730.2430.308Example 50.1230.1710.2390.2830.1180.1580.2230.277Example 60.0990.1390.1870.2300.1060.1480.2010.246Comparative Example 10.1420.2560.2870.3620.1390.2020.2770.336Comparative Example 20.1370.1890.2580.3300.1580.2130.2940.364

[0366] Evaluation Example 9. Density Evaluation

[0367] The density evaluation of the polymer electrolyte membranes manufactured according to Examples 1 to 6 and Comparative Examples 1 to 2 was measured as follows.

[0368] The density was measured using the density kit of the ML54T device from Mettler Toledo. The solution used for density measurement was distilled water, and the density was measured using the buoyancy of water.

[0369] The results at this time are shown in Table 13 below.

[0370] Density (g / cm) 3 )Example 11.94Example 21.95Example 31.95Example 41.96Example 51.90Example 61.90Comparative Example 11.90Comparative Example 21.85

[0371] Evaluation Example 10. Measurement of surface-direction compressive resistance

[0372] The surface direction compressive resistance of the polymer electrolyte membranes manufactured according to Examples 1 to 6 and Comparative Examples 1 to 2 was measured as follows.

[0373] A sample was prepared using the polymer electrolyte membrane cut to be 50 mm wide and 50 mm long, and the sample was placed on a flat surface. Then, using a needle with a diameter of 15 mm and a load cell of 1 kN, the surface compressive resistance was measured using an Instron6800 series device at a test speed of 10 mm / min.

[0374] The results at this time are shown in Table 14 below.

[0375] Compression resistance (N) Example 1 38.0 Example 2 42.1 Example 3 46.4 Example 4 35.6 Example 5 34.5 Example 6 39.3 Comparative Example 140.2 Comparative Example 235.4

[0376] Evaluation Example 11. Performance Evaluation

[0377] The performance evaluation of the polymer electrolyte membranes manufactured according to Examples 1 to 6 and Comparative Examples 1 to 2 was measured as follows.

[0378] The catalyst mixture for fabricating the hydrogen electrode (HER) is a mixture of 50 wt% Pt / C catalyst and polymer binder in a ratio of 1:1.2 and a solid content ratio of 5 wt%. The catalyst loading is 1.0 mg / cm 2 To this end, the active area is 4 cm using a spray coating method on the electrode coating substrate film. 2 A hydrogen electrode was fabricated.

[0379] The catalyst mixture for the fabrication of oxygen electrode (OER) is IrO X The catalyst and polymer binder are mixed in a ratio of 1:0.2 and the solid content ratio is 5 wt%. The same coating method as the hydrogen electrode is used to make the catalyst loading 0.5 mg / cm2, and the active area is 4 cm. 2 An oxygen electrode was fabricated.

[0380] A hydrogen electrode, a polymer electrolyte membrane manufactured according to Examples 1 to 6 and Comparative Examples 1 to 2, and an oxygen electrode were sequentially laminated and thermally compressed at 150°C for 5 minutes.

[0381] Using a multichannel potentiometer (Bio-Logic, HCP-803 Potentiostat) and a pump (KNF Neuberger, SIMDOS 02 FEM 1.02S), water was supplied at 80°C and 5 mL / min at atmospheric pressure, with an active area of ​​9 cm. 2 The performance of the membrane-electrode assembly manufactured was evaluated.

[0382] The performance evaluation of the membrane-electrode assembly at this time is shown in Fig. 1.

[0383]

[0384] Although the preferred embodiments have been described in detail above, the scope of the rights is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concepts defined in the following claims also fall within the scope of the rights.

Claims

1. Contains ionic conductors, solvents, environmentally friendly additive solvents and non-solvents. The pKa value of the above eco-friendly additive solvent is within the range of 0 to 7.

5. The above eco-friendly additive solvent has a dispersion term of Hansen solubility parameter of 16 MPa. 0.5 Above, the polarity term is 6 MPa 0.5 Above, the hydrogen bonding term is 13 MPa. 0.5 Satisfying the following, Ionic conductor dispersion composition.

2. In paragraph 1, The above eco-friendly additive solvent has a score of 4 to 10 in all items according to the solvent selection guide criteria of GSK. Ionic conductor dispersion composition.

3. In paragraph 1, The above eco-friendly additive solvent is a polar aprotic solvent, The polar aprotic solvent is selected from the group consisting of γ-Butyrolactone, Methyl L-lactate, γ-Valerolactone, ethyl lactate, dimethyl carbonate, cyclic carbonate, succinic acid, diformylxylose, pentanoic acid, 5-(dimethylamino)-2-methyl-5-oxo-, methyl ester; CAS No. 1174627-68-9, dihydrolevoglucosenone, methyl sesamol, or a combination thereof. Ionic conductor dispersion composition.

4. In paragraph 1, The distance (R) between the Hansen solubility parameter of the ion conductor and the Hansen solubility parameter of the mixture of the solvent, the eco-friendly additive solvent, and the nonsolvent, calculated according to the following mathematical expression 1 a ) is 0.1 MPa 0.5 Up to 30 MPa 0.5 Within the scope of, The dispersion term, polarity term and hydrogen bond term of the Hansen solubility parameter of the mixture of the above solvent, the above eco-friendly additive solvent and the above non-solvent are calculated according to the following mathematical formulas 2-1 to 2-3. Ionic Conductor Dispersion Composition: [Mathematical Formula 1] In the above mathematical expression 1, Above δ d1 (Unit: MPa 0.5 ) is the dispersion term of the above ion conductor, Above δ d2 (Unit: MPa 0.5 ) is the dispersion term of the above mixture, Above δ p1 (Unit: MPa 0.5 ) is the polarity term of the above ion conductor, Above δ p2 (Unit: MPa 0.5 ) is the polarity of the mixture, Above δ h1 (Unit: MPa 0.5 ) is the hydrogen bond term of the above ion conductor, Above δ h2 (Unit: MPa 0.5 ) is the hydrogen bonding term of the above mixture: [Mathematical expression 2-1] [Mathematical expression 2-2] [Mathematical expression 2-3] In mathematical expressions 2-1 to 2-3, δ d2 is the dispersion term of the mixture, and δ p2 is the polarity of the mixture, and δ h2 is the hydrogen bonding term of the mixture, w1 is the weight of the solvent, w2 is the weight of the eco-friendly added solvent, w3 is the weight of the nonsolvent, and δ d,1 , δ p,1 , δ h,1 are the dispersion term, polar term, and hydrogen bonding term of the Hansen solubility parameter of the solvent, respectively, and δ d,2 , δ p,2 , δ h,2 is the dispersion term, polarity term, and hydrogen bonding term of the Hansen solubility parameter of the eco-friendly additive solvent, and δ d,3 , δ p,3 , δ h,3 are the dispersion term, polar term, and hydrogen bonding term of the Hansen solubility parameter of the nonsolvent.

5. In paragraph 1, The above-mentioned eco-friendly additive solvent is included in a range of 3 wt% to 20 wt% based on the total weight of the above-mentioned ion conductor dispersion composition, The above solvent is included in the range of 180 to 1000 parts by weight based on 100 parts by weight of the above eco-friendly additive solvent. The above non-solvent is included in the range of 100 to 500 parts by weight based on 100 parts by weight of the above eco-friendly additive solvent. Ionic conductor dispersion composition.

6. In paragraph 1, Using rheometer equipment, the viscosity is measured under flow sweep measurement protocol and 25℃ conditions, and is within the range of 200 cP to 1100 cP. Ionic conductor dispersion composition.

7. In paragraph 1, An ion conductor dispersion composition having a change in contact angle for a support of 30% to 60% calculated according to the following Equation 1: [Formula 1] Rate of change in contact angle on support = (ab) / a 100 In Equation 1, a is the contact angle with respect to the support when the ion conductor dispersion composition is dropped on the support for the first time, and b is the contact angle with respect to the support when the ion conductor dispersion composition is dropped on the support for the 200th time.

8. In paragraph 1, The size of the ion conductor dispersion particles in the above ion conductor dispersion composition is within the range of 500 nm to 2000 nm. Ionic conductor dispersion composition.

9. In paragraph 1, The ion conductor polydispersity index in the above ion conductor dispersion composition is in the range of 0.9 to 1.

5. Ionic conductor dispersion composition.

10. Mix the ion conductor with the solvent to prepare a primary mixture, An eco-friendly additive solvent is added to the first mixture and mixed to prepare a second mixture. A non-solvent is added to the above secondary mixture and mixed to prepare an ion conductor dispersion composition, It includes manufacturing a polymer electrolyte membrane by coating the above ion conductor dispersion composition on a substrate and then performing drying and heat treatment. The pKa value of the above eco-friendly additive solvent is within the range of 0 to 7.5, The above eco-friendly additive solvent has a dispersion term of Hansen solubility parameter of 16 MPa. 0.5 Above, the polarity term is 6 MPa 0.5 Above, the hydrogen bonding term is 13 MPa 0.5 Satisfying the following, Method for manufacturing a polymer electrolyte membrane.

11. In paragraph 10, After coating the ion conductor dispersion composition on the above substrate, before drying and heat treatment, Further comprising placing a porous support on a substrate coated with the ion conductor dispersion composition, and re-coating the ion conductor dispersion composition on the porous support. Method for manufacturing a polymer electrolyte membrane.

12. In paragraph 11, The above drying is performed at a temperature within the range of 60°C to 120°C, The above heat treatment is performed at a temperature within the range of 150°C to 220°C when a fluorine-based ion conductor is used, and at a temperature within the range of 80°C to 500°C when a hydrocarbon-based ion conductor is used. Method for manufacturing a polymer electrolyte membrane.

13. A porous support comprising a plurality of pores, and Containing an ion conductor filling the pores of the above porous support, A haze of 0.1% to 10% as measured by a light transmittance instrument, Polymer electrolyte membrane.

14. In paragraph 13, A polymer electrolyte membrane having a total light transmittance (Tt) of 90% or more as measured by a total light transmittance measuring device.

15. In paragraph 13, A polymer electrolyte membrane having a tensile strength in the longitudinal direction (MD) of 35 MPa or more and a tensile strength in the transverse direction (TD) of 30 MPa or more.

16. In paragraph 13, A polymer electrolyte membrane in which the absolute value of the difference between the elongation in the longitudinal direction (MD) and the elongation in the transverse direction (TD) is 50% or less.

17. In paragraph 13, A polymer electrolyte membrane having a surface-wise wet swelling ratio of 20% or less as measured at 15 to 25°C.

18. In paragraph 13, A polymer electrolyte membrane having a surface-wise wet expansion coefficient of 40% or less as measured at 75 to 85°C.

19. Polymer electrolyte membrane according to Article 13; A hydrogen electrode located on one side of the polymer electrolyte membrane; and A membrane-electrode assembly comprising an air electrode positioned on the other side of the polymer electrolyte membrane.

20. An electrochemical cell comprising a membrane-electrode assembly according to claim 19.

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