Hydrocarbon membranes

Abstract

The present disclosure provides an ion conducting membrane comprising a sulfonated hydrocarbon ionomer wherein the ion conducting membrane has a lambda value of less than about 60.

Description

Technical Field

[0001] This invention relates to ion-conducting membranes containing sulfonated ionomers, which exhibit reduced water absorption. Specifically, this invention relates to proton exchange membranes and methods for manufacturing the same. The ion-conducting membranes are suitable for use in electrochemical devices such as fuel cells and / or electrolyzers. Background Technology

[0002] A fuel cell is an electrochemical cell comprising two electrodes separated by an electrolyte. Fuel (e.g., hydrogen, alcohol (such as methanol or ethanol), or formic acid) is supplied to the anode, and an oxidant (e.g., oxygen or air) is supplied to the cathode. Electrochemical reactions occur at the electrodes, and the chemical energy of the fuel and oxidant is converted into electrical energy and heat. Electrocatalysts are used to facilitate the electrochemical oxidation of the fuel at the anode and the electrochemical reduction of oxygen at the cathode.

[0003] Fuel cells are typically classified according to the properties of the electrolyte used. The electrolyte is usually a solid polymer membrane, which is electrically insulating but ionicly conductive. In a proton exchange membrane fuel cell (PEMFC), the membrane is proton-conductive, and protons generated at the anode are transported across the membrane to the cathode, where they combine with oxygen to form water.

[0004] An electrolyzer is an electrochemical device used to electrolyze water to produce high-purity hydrogen and oxygen. Electrolyzers can operate in both alkaline and acidic systems. Those electrolyzers that employ solid proton-conducting polymer electrolyte membranes or proton exchange membranes (PEMs) are called proton exchange membrane water electrolyzers (PEMWEs).

[0005] Traditionally, perfluorosulfonic acid (PFSA) ionomers have been used in proton exchange membranes due to their long-proven advantages in membrane performance, durability, and manufacturability. However, due to environmental concerns, such as those related to fluorinated chemicals, there is an active search for hydrocarbon-based ionomers as alternatives to PFSA ionomers.

[0006] Many different hydrocarbon ionomers have been studied, primarily focusing on those that incorporate aromatic groups as part of the polymer backbone, such as poly(aryl ethers), poly(aryl ether ketones), poly(aryl sulfones), poly(imides), poly(benzimidazoles), polyphenylene, and sulfonated derivatives of phenylenediamine. However, membranes made from hydrocarbon ionomers to date do not meet the performance and manufacturability thresholds required for commercial membrane products. For example, current membranes containing hydrocarbon ionomers swell excessively without mechanical support and cannot effectively regulate water within the membrane during operation. It is desirable to provide membranes made from hydrocarbon ionomers that address these issues. Summary of the Invention

[0007] Therefore, this disclosure provides an ion-conducting membrane comprising a sulfonated hydrocarbon ionomer, wherein the ion-conducting membrane has a λ value of less than about 60. Thus, the ion-conducting membrane is a hydrocarbon membrane, i.e., it does not contain a fluorinated ionomer. As stated herein, λ is a measure of water absorption and, in the case of this invention, is measured after water absorption at about 80°C, representing the temperature faced during actual use, such as in a proton exchange membrane fuel cell, for example, in automotive applications. This value is surprisingly and advantageously low. In prior art disclosures where λ is measured after water absorption at ambient temperatures (such as 22°C), λ is naturally lower at such temperatures because water absorption is less convenient at lower temperatures. However, such temperatures do not represent the temperatures faced during actual use of the membrane. Suitably, the ion-conducting membrane has a wet film mean domain spacing (Å) of less than or equal to about 37, as determined by small-angle X-ray scattering (SAXS), and suitably, the ion-conducting membrane has a wet film correlated length (Å) of less than or equal to about 9, as determined by SAXS. Therefore, the inventors have surprisingly discovered that ion-conducting membranes made from sulfonated hydrocarbon ionomers absorb less water and exhibit higher dimensional stability, thereby reducing swelling. These are the fundamental effects of providing ion-conducting membranes containing sulfonated hydrocarbon ionomers, which can operate effectively in fuel cells or water electrolyzers.

[0008] This disclosure also provides a method for preparing an ion-conducting membrane according to this disclosure, the method comprising casting the membrane from a mixture of a sulfonated hydrocarbon ionomer and a solvent. The inventors have surprisingly discovered that ion-conducting membranes comprising sulfonated hydrocarbon ionomers having the advantageous properties discussed above can be cast at ambient temperatures, and that these properties can be controlled by the characteristics of the solvent.

[0009] This disclosure also provides a catalyst-coated membrane for use in fuel cells or water electrolyzers, the catalyst-coated membrane comprising an ion-conducting membrane according to this disclosure, wherein a cathode catalyst layer is applied to a first side of the membrane and / or an anode catalyst layer is applied to a second side of the membrane. The catalyst layer may comprise a perfluorosulfonic acid ionomer or a hydrocarbon ionomer.

[0010] This disclosure also provides a membrane electrode assembly for a fuel cell or a water electrolyzer, the membrane electrode assembly comprising (i) an ion-conducting membrane according to this disclosure; or (ii) a membrane coated with a catalyst according to this disclosure; and at least one of a gas diffusion layer or a porous transport layer.

[0011] This disclosure also provides a water electrolyzer or fuel cell, which includes a membrane coated with a catalyst according to this disclosure or a membrane electrode assembly according to this disclosure. Attached Figure Description

[0012] Figure 1This is a graph showing the percentage change in mass of a membrane containing sulfonated hydrocarbon ionomers between dry and wet states relative to the length of the alcohol chains cast from the membrane.

[0013] Figure 2 This is a graph showing the normalized values ​​of the mass change between different states when compared to the environmental state of a membrane containing sulfonated hydrocarbon ionomers cast from alcohols with different chain lengths.

[0014] Figure 3 This is a graph showing the λ values ​​of ion-conducting films containing sulfonated hydrocarbon ionomers cast from alcohols with different chain lengths.

[0015] Figure 4 It is a graph showing the swelling of an ion-conducting film containing sulfonated hydrocarbon ionomers cast from alcohols with different chain lengths in the transverse and in-plane directions.

[0016] Figure 5 This is a graph showing the swelling of an ion-conducting film containing sulfonated hydrocarbon ionomers cast from alcohols with different chain lengths in the direction of the through-plane.

[0017] Figure 6 This is a graph showing the relevant lengths and domain spacings of ion-conducting films containing sulfonated hydrocarbon ionomers cast from alcohols with different chain lengths, as determined by small-angle X-ray scattering (SAXS).

[0018] Figure 7 This is a graph showing the trends of λ values ​​and cast alcohol chain lengths relative to relevant lengths and domain spacing for ion-conducting films containing sulfonated hydrocarbon ionomers, as determined by SAXS. Detailed Implementation

[0019] An ionomer is a polymer composed of repeating units of both an electrically neutral repeating unit and an ionized unit covalently bonded to the electrically neutral repeating unit as a side group. In hydrocarbon ionomers, the electrically neutral repeating unit is hydrocarbon-based and does not contain fluorine substituents. In sulfonated hydrocarbon ionomers, the ionized unit is a sulfonate moiety. Suitably, sulfonated hydrocarbon ionomers are selected from poly(aryl ethers), poly(aryl ether ketones), poly(aryl sulfones), poly(imides), poly(benzimidazoles), polyphenylene, and sulfonated derivatives of phenylenediphenylene. Typically, sulfonated hydrocarbon ionomers are sulfonated polyphenylene hydrocarbon ionomers. Sulfonated polyphenylene hydrocarbon ionomers are linear sulfonated polyphenylene, twisted sulfonated polyphenylene, side-chain sulfonated polyphenylene, or sulfonated phenylenediphenylene hydrocarbon ionomers. Such motifs are known to those skilled in the art, for example as described in the following literature: “On the evolution of sulfonated polyphenylenes as proton exchange membranes for fuel cells”, Mater. Adv. 2021, 2, pp. 4966-5005. More typically, sulfonated hydrocarbon ionomers are sulfonated phenylenediene polyphenylene ionomers, such as Pemion from Ionomr Innovations. ™ A series of sulfonated hydrocarbon ionomers. Sulfonated phenylene hydrocarbon ionomers can be linear or branched.

[0020] Sulfonated phenylenediamine ionomers typically comprise a core repeating unit containing a sulfonated moiety comprising at least three aryl and / or heteroaryl groups linked by carbon-carbon single bonds. Typically, the core repeating unit contains no more than ten, and more typically no more than nine, aryl and / or heteroaryl groups. Typically, the core repeating unit contains at least five aryl and / or heteroaryl groups. The core repeating unit may comprise nine aryl and / or heteroaryl groups and may be obtained by cycloaddition of the sulfonated bis(tetracyclic) ketone moiety with diphenylacetylene, as described in the following references: Mater. Adv. 2021, 2, pp. 4966-5005 and “Structurally-Defined, Sulfo-Phenylated, Oligophenylenes and Polyphenylenes”, J. Am. Chem. Soc., 2015, 137, pp. 12223-12226, and WO 2018 / 187864, the entire contents of which are incorporated herein by reference. The repeating unit may also comprise a linking group comprising heteroaryl and / or aryl groups, typically at least one and no more than ten, and more typically no more than seven such groups. Suitably, the linking group comprises one or more phenyl groups, typically only phenyl groups. Suitably, the linking group comprises one or more naphthyl groups. Suitably, the linking group comprises one or more pyridyl groups.

[0021] The sulfonated phenylenediamine ionomer may also comprise a core hydrophobic repeating unit that does not contain a sulfonate moiety and may contain at least three aryl and / or heteroaryl groups linked by carbon-carbon single bonds. Typically, the core repeating unit contains no more than ten, and more typically no more than nine aryl and / or heteroaryl groups. Typically, the core repeating unit contains at least five aryl and / or heteroaryl groups. The core repeating unit may contain nine aryl and / or heteroaryl groups and may be obtained by cycloaddition of a bis(tetracyclic) ketone moiety with diphenylacetylene, as described in WO 2018 / 187864, the entire text of which is incorporated herein by reference. The hydrophobic repeating unit may also comprise a linking group comprising heteroaryl and / or aryl groups, typically at least one and no more than ten, and more typically no more than seven such groups. Suitably, the linking group comprises one or more phenyl groups, typically only phenyl groups. Suitably, the linking group comprises one or more naphthyl groups. Suitably, the linking group comprises one or more pyridyl groups.

[0022] The molar ratio of repeating units containing sulfonated moieties to hydrophobic repeating units can suitably range from about 1:99 to about 99:1, suitably from about 1:50 to about 50:1, more suitably from about 1:25 to about 25:1, typically from about 1:10 to about 10:1, for example from about 1:2.5 to about 2.5:1, and including end values. The sulfonated hydrocarbon ionomer can be a block copolymer comprising a first block having repeating units containing sulfonated moieties as defined above and a second block having second repeating units containing hydrophobic repeating units as defined above. The number of repeating units containing sulfonated moieties in the first block can range from about three to about one hundred, and including end values, and the number of repeating units containing hydrophobic repeating units in the second block can range from about three to about one hundred, and including end values.

[0023] Sulfonated hydrocarbon ionomers may suitably contain repeating units of formula (I):

[0024]

[0025] in:

[0026] R 1A R 1B R 1C R 1D R 1E and R 1F Independently aryl or heteroaryl, each optionally composed of 1, 2, 3, 4 or 5 independently selected from C 1-6 Alkyl, halogen, nitro, cyano and SO3 - X + Substituents of X, wherein X + For H + Or a cation, and the prerequisite is R 1A R 1B R 1C R 1D R 1E and R 1F At least two of them are independently aryl or heteroaryl, each optionally bonded by 1, 2, 3, 4 or 5 SO3 groups. - X + Substituent substitution;

[0027] R 1G and R 1H Independently H, aryl, or heteroaryl, wherein each of the aryl and heteroaryl groups is optionally selected from C1, 2, 3, 4, or 5 independently from C2. 1-6 Alkyl, halogen, nitro, cyano and SO3 - X + Substituents of X, wherein X + For H +Or cations, typically, R 1G and R 1H For H;

[0028] A1 is an arylene, heteroarylene, or heteroalkyl group, each optionally substituted by 1, 2, 3, 4, or 5 substituents independently selected from halogen, nitro, cyano, aryl, and heteroaryl groups;

[0029] A2 is absent and is arylene, heteroarylene, or heteroalkyl, wherein each of the arylene and heteroarylene is optionally substituted by 1, 2, 3, 4, or 5 substituents independently selected from halogen, nitro, cyano, aryl, and heteroaryl.

[0030] L1 is an optionally substituted linking heteroatom, arylene, heteroarylene, arylene alkyl, or heteroarylene alkyl, wherein each of the arylene, heteroarylene, arylene alkyl, and heteroarylene alkyl is optionally selected independently by 1, 2, 3, or 4 C atoms. 1-6 Substitution of alkyl, halogen, nitro, cyano, aryl, and heteroaryl groups;

[0031] L2 is absent, and is either arylene or heteroarylene, wherein each of the arylene and heteroarylene is optionally selected independently from C1, 2, 3, or 4 C2 groups. 1-6 Substitution with alkyl, halogen, nitro, cyano, aryl, and heteroaryl groups; and

[0032] L3 is absent, and is either arylene or heteroarylene, wherein each of the arylene and heteroarylene is optionally selected independently from C1, 2, 3, or 4 C2 groups. 1-6 Substitution with alkyl, halogen, nitro, cyano, aryl, and heteroaryl substituents.

[0033] R 1G and R 1H It can be H independently.

[0034] The repeating unit in equation (I) can be appropriately the repeating unit in equation (IA):

[0035]

[0036] in:

[0037] R 1A R 1B R 1C R 1D R 1E and R 1F Independently aryl or heteroaryl, each optionally composed of 1, 2, 3, 4 or 5 independently selected from C 1-6 Alkyl, halogen, nitro, cyano and SO3 - X + Substituents of X, wherein X+ For H + Or a cation, and the prerequisite is R 1A R 1B R 1C R 1D R 1E and R 1F At least two of them are independently aryl or heteroaryl, each optionally bonded by 1, 2, 3, 4 or 5 SO3 groups. - X + Substituent substitution;

[0038] R 2A R 2B R 2C R 2D It can be independently H, halogen, nitro, cyano, aryl, or heteroaryl;

[0039] L1 is an optionally substituted linking heteroatom, arylene, heteroarylene, arylene alkyl, or heteroarylene alkyl, wherein each of the arylene, heteroarylene, arylene alkyl, and heteroarylene alkyl is optionally selected independently by 1, 2, 3, or 4 C atoms. 1-6 Substitution of alkyl, halogen, nitro, cyano, aryl, and heteroaryl groups;

[0040] L2 is absent, and is either arylene or heteroarylene, wherein each of the arylene and heteroarylene is optionally selected independently from C1, 2, 3, or 4 C2 groups. 1-6 Substitution with alkyl, halogen, nitro, cyano, aryl, and heteroaryl groups; and

[0041] L3 is absent, and is either arylene or heteroarylene, wherein each of the arylene and heteroarylene is optionally selected independently from C1, 2, 3, or 4 C2 groups. 1-6 Substitution with alkyl, halogen, nitro, cyano, aryl, and heteroaryl substituents.

[0042] R 1A R 1B R 1C R 1D R 1E and R 1F It can be independently aryl or heteroaryl, each optionally bonded by 1, 2, 3, 4 or 5 SO3 groups. - X + Replace, where X + For H + Or a cation, and the prerequisite is R 1A R 1B R 1C R 1D R 1E and R 1FAt least two of them are independently controlled by 1, 2, 3, 4 or 5 SO3 groups. - X + Substituted aryl or heteroaryl groups. R 1A R 1B R 1C R 1D R 1E and R 1F It can be independently, optionally by 1, 2, 3, 4 or 5 SO3 groups. - X + Substituted aryl, wherein X + For H + Or a cation, and the prerequisite is R 1A R 1B R 1C R 1D R 1E and R 1F At least two of them are independently controlled by 1, 2, 3, 4 or 5 SO3 groups. - X + Substituted aryl group. R 1A R 1B R 1C R 1D R 1E and R 1F It can be independently, optionally by 1, 2, 3, 4 or 5 SO3 groups. - X + Substituted phenyl, wherein X + For H + Or a cation, and the prerequisite is R 1A R 1B R 1C R 1D R 1E and R 1F At least two of them are independently controlled by 1, 2, 3, 4 or 5 SO3 groups. - X + Substituted phenyl groups.

[0043] X + H can be + Or selected from [N(R)] 5A ) (R 5B ) (R 5C ) (R 5D )] + And cations of alkali metal ions, of which R 5A R 5B R 5C R 5D H and C independently 1-6 Alkyl, aryl, or heteroaryl.

[0044] A1 may be arylene, optionally substituted with 1, 2, 3, 4 or 5 substituents independently selected from halogen, nitro, cyano, aryl and heteroaryl. A2 may be absent. Alternatively, A2 may be arylene, optionally substituted with 1, 2, 3, 4 or 5 substituents independently selected from halogen, nitro, cyano, aryl and heteroaryl.

[0045] R 2A R 2B R 2C R 2D It can be either H or halogen independently. Typically, R... 2A R 2B R 2C R 2D Each is represented by H.

[0046] L1 can be arylene or heteroarylene, each optionally composed of 1, 2, 3, or 4 independently selected from C. 1-6 Alkyl, halogen, aryl, and heteroaryl substituents. Suitably, L1 is arylene or heteroarylene, each optionally substituted with 1, 2, 3, or 4 independently selected from C1. 1-6 Alkyl and halogen substituents. Typically, L1 is arylene or heteroarylene, each optionally replaced by 1, 2, 3, or 4 carbons. 1-6 Alkyl substitution. Typically, L1 is arylene or heteroarylene. Suitably, L1 is arylene, optionally with 1, 2, 3 or 4 alkyl groups independently selected from C1. 1-6 Alkyl and halogen substituents. Typically, L1 is arylene, optionally with 1, 2, 3, or 4 carbons. 1-6 Alkyl substitution. Typically, L1 is arylene. L1 can be naphthylene, phenylene, or C. 1-6 Alkyl-substituted phenylene. Suitablely, L1 is phenylene or C. 1-6 Alkyl-substituted phenylene oxides.

[0047] L2 may be absent. Alternatively, L2 may be arylene or heteroarylene, wherein each of the arylene and heteroarylene groups is optionally selected independently from C1, 2, 3, or 4 C2 groups. 1-6 Alkyl and halogen substituents. L2 can be arylene or heteroarylene, wherein the arylene and heteroarylene are each optionally replaced by 1, 2, 3 or 4 carbon atoms. 1-6 Alkyl substitution. L2 can be arylene or heteroarylene. L2 can be arylene, wherein the arylene is optionally composed of 1, 2, 3, or 4 independently selected from C10. 1-6 Alkyl and halogen substituents. L2 may be arylene, wherein the arylene is optionally replaced by 1, 2, 3 or 4 carbon atoms. 1-6 Alkyl substitution. L2 can be arylene. L2 can be phenylene.

[0048] L3 may be absent. Alternatively, L3 may be arylene or heteroarylene, wherein each of the arylene and heteroarylene groups is optionally selected independently from C1, 2, 3, or 4 C2 groups. 1-6 Alkyl and halogen substituents. L3 can be arylene or heteroarylene, wherein the arylene and heteroarylene are each optionally replaced by 1, 2, 3 or 4 carbon atoms. 1-6 Alkyl substitution. L3 can be arylene or heteroarylene. L3 can be arylene, wherein the arylene is optionally composed of 1, 2, 3, or 4 independently selected from C10. 1-6 Alkyl and halogen substituents. L3 may be arylene, wherein the arylene is optionally replaced by 1, 2, 3 or 4 carbon atoms. 1-6 Alkyl substitution. L3 can be arylene. L3 can be phenylene.

[0049] Equation (I) can be a repeating unit of equation (IB):

[0050]

[0051] -L3-L2-L1- can be selected from:

[0052]

[0053]

[0054]

[0055]

[0056]

[0057] .

[0058] Sulfonated hydrocarbon ionomers may also contain hydrophobic repeating units of formula (II):

[0059]

[0060] in:

[0061] R 3A R 3B R 3C R 3D R 3E and R 3F Independently aryl or heteroaryl, each optionally composed of 1, 2, 3, 4 or 5 independently selected from C 1-6 Substitution of alkyl, halogen, nitro, and cyano groups;

[0062] R 3G and R 3H Independently H, aryl, or heteroaryl, wherein each of the aryl and heteroaryl groups is optionally selected from C1, 2, 3, 4, or 5 independently from C2. 1-6 Substitution of alkyl, halogen, nitro, and cyano groups, usually R 3G and R 3H H is independent;

[0063] B1 is arylene, heteroarylene, arylene alkyl, or heteroarylene, each optionally substituted by 1, 2, 3, or 4 substituents independently selected from halogen, nitro, cyano, aryl, and heteroaryl;

[0064] B2 is absent, and is arylene or heteroarylene, wherein each of the arylene and heteroarylene is optionally substituted by 1, 2, 3 or 4 substituents independently selected from halogen, nitro, cyano, aryl and heteroaryl;

[0065] K1 is an optionally substituted linking heteroatom, arylene, heteroarylene, arylene alkyl, or heteroarylene alkyl, wherein each of the arylene, heteroarylene, arylene alkyl, and heteroarylene alkyl is optionally selected independently by 1, 2, 3, or 4 C atoms. 1-6 Substitution of alkyl, halogen, nitro, cyano, aryl, and heteroaryl groups;

[0066] K2 is absent, and is either arylene or heteroarylene, wherein each of the arylene and heteroarylene groups is optionally selected independently from C1, 2, 3, or 4. 1-6 Substitution with alkyl, halogen, nitro, cyano, aryl, and heteroaryl groups; and

[0067] K3 is absent, and is either arylene or heteroarylene, wherein each of the arylene and heteroarylene groups is optionally selected independently from C1, 2, 3, or 4 C2 groups. 1-6 Substitution with alkyl, halogen, nitro, cyano, aryl, and heteroaryl substituents.

[0068] The repeating unit in equation (II) can be appropriately the repeating unit in equation (II-A):

[0069]

[0070] in:

[0071] R 3A R 3B R 3C R 3D R 3E and R 3F Independently aryl or heteroaryl, each optionally composed of 1, 2, 3, 4 or 5 independently selected from C 1-6 Substitution of alkyl, halogen, nitro, and cyano groups;

[0072] R 4A R 4B R 4C R 4D It can be independently H, halogen, nitro, cyano, aryl, or heteroaryl;

[0073] K1 is an optionally substituted linking heteroatom, arylene, heteroarylene, arylene alkyl, or heteroarylene alkyl, wherein each of the arylene, heteroarylene, arylene alkyl, and heteroarylene alkyl is optionally selected independently by 1, 2, 3, or 4 C atoms. 1-6 Substitution of alkyl, halogen, nitro, cyano, aryl, and heteroaryl groups;

[0074] K2 is absent, and is either arylene or heteroarylene, wherein each of the arylene and heteroarylene groups is optionally selected independently from C1, 2, 3, or 4. 1-6 Substitution with alkyl, halogen, nitro, cyano, aryl, and heteroaryl groups; and

[0075] K3 is absent, and is either arylene or heteroarylene, wherein each of the arylene and heteroarylene groups is optionally selected independently from C1, 2, 3, or 4 C2 groups. 1-6 Substitution with alkyl, halogen, nitro, cyano, aryl, and heteroaryl substituents.

[0076] R 3A R 3B R 3C R 3D R 3E and R 3F It can be independently aryl, optionally composed of 1, 2, 3, 4 or 5 independently selected C 1-6 Alkyl and halogen substituents. R 3A R 3B R 3C R 3D R 3E and R 3F It can be independently phenyl, optionally composed of 1, 2, 3, 4 or 5 molecules independently selected from C. 1-6 Alkyl and halogen substituents.

[0077] B1 may optionally be arylene and may optionally be substituted by 1, 2, 3 or 4 substituents independently selected from halogen, nitro, cyano, aryl and heteroaryl.

[0078] B2 may be absent. Alternatively, B2 may be arylene and optionally substituted by 1, 2, 3 or 4 substituents independently selected from halogen, nitro, cyano, aryl and heteroaryl.

[0079] R 4A R 4B R 4C R 4D It can be either H or halogen independently. Typically, R... 4A R 4B R 4C R 4D Each is represented by H.

[0080] K1 can be arylene or heteroarylene, each optionally composed of 1, 2, 3, or 4 independently selected from C. 1-6 Substituents of alkyl, halogen, aryl, and heteroaryl groups. K1 can be arylene or heteroarylene, each optionally replaced by 1, 2, 3, or 4 independently selected C1 groups. 1-6 Alkyl and halogen substituents. K1 can be arylene or heteroarylene, each optionally replaced by 1, 2, 3 or 4 carbons. 1-6 Alkyl substitution. K1 can be alkyl or heteroaryl. K1 can be aryl, optionally with 1, 2, 3 or 4 independently selected from C1. 1-6 Alkyl and halogen substituents. K1 can be arylene, optionally with 1, 2, 3 or 4 carbon atoms. 1-6 Alkyl substitution. K1 can be arylene. K1 can be naphthylene, phenylene, or C. 1-6 Alkyl-substituted phenylene. K1 can be phenylene or C. 1-6 Alkyl-substituted phenylene oxides.

[0081] K2 may be absent. Alternatively, K2 may be arylene or heteroarylene, wherein each of the arylene and heteroarylene groups is optionally selected independently from C1, 2, 3, or 4 C2 groups. 1-6 Alkyl and halogen substituents. K2 can be arylene or heteroarylene, wherein the arylene and heteroarylene are each optionally replaced by 1, 2, 3 or 4 carbon atoms. 1-6 Alkyl substitution. K2 may be absent, and may be arylene or heteroarylene. K2 may be arylene, wherein the arylene groups are optionally selected independently from C1, C2, C3, or C4. 1-6 Alkyl and halogen substituents. K2 may be arylene, wherein the arylene is optionally replaced by 1, 2, 3 or 4 carbon atoms. 1-6 Alkyl substitution. K2 can be arylene. K2 can be phenylene.

[0082] K3 may be absent. Alternatively, K3 may be arylene or heteroarylene, wherein each of the arylene and heteroarylene groups is optionally selected independently from C1, 2, 3, or 4 C2 groups. 1-6 Alkyl and halogen substituents. K3 can be arylene or heteroarylene, wherein the arylene and heteroarylene are each optionally replaced by 1, 2, 3 or 4 carbon atoms. 1-6 Alkyl substitution. K3 can be arylene or heteroarylene. K3 can be arylene, wherein the arylene is optionally composed of 1, 2, 3, or 4 independently selected from C10. 1-6 Alkyl and halogen substituents. K3 may be arylene, wherein the arylene is optionally replaced by 1, 2, 3 or 4 carbon atoms. 1-6 Alkyl substitution. K3 can be arylene. K3 can be phenylene.

[0083] Equation (II) can be appropriately represented as a repeating unit of equation (II-B):

[0084] .

[0085] -K3-K2-K1- can be selected from:

[0086]

[0087]

[0088]

[0089]

[0090]

[0091]

[0092] .

[0093] Sulfonated hydrocarbon ionomers may suitably comprise a first repeating unit of formula (I) as defined above and a second repeating unit of formula (II) as defined above, wherein the molar ratio of the first repeating unit to the second repeating unit is in the range of 1:99 to 99:1, suitably about 1:50 to about 50:1, more suitably about 1:25 to about 25:1, typically about 1:10 to about 10:1, for example about 1:2.5 to about 2.5:1 and including end values. Sulfonated hydrocarbon ionomers are block copolymers comprising a first block having repeating units of formula (I) as defined above and a second block having second repeating units of formula (II) as defined above. The number of repeating units of formula (I) in the first block may range from about three to about one hundred and including end values, and the number of repeating units of formula (II) in the second block may range from about three to about one hundred and including end values.

[0094] Sulfonated hydrocarbon ionomers can be linear. Sulfonated hydrocarbon ionomers can be branched.

[0095] The sulfonated hydrocarbon ionomer may further comprise a multivalent linker M1 directly bonded to at least three repeating units via covalent bonds. M1 may be a trivalent, tetravalent, pentavalent, or hexavalent linker. Suitably, M1 is selected from carbon atoms, heteroatoms (e.g., N, P, or B), polyaryl groups, polyheteroaryl groups, polyaralkyl groups, or polyheteroaryl groups, wherein the carbon atom, heteroatomium (e.g., P), polyaryl group, polyheteroaryl group, polyaralkyl group, or polyheteroaryl group is optionally each selected by one, two, or three independently selected from C… 1-6 Substituents of alkyl, halogen, nitro, cyano, aryl, and heteroaryl groups. Suitably, M1 may be selected from trivalent nitrogen, tetravalent carbon, trivalent phenyl, trivalent pyridyl, trivalent pyrazolyl, tetravalent phenyl, tetravalent pyridyl, tetravalent pyrazolyl, pentavalent phenyl, pentavalent pyridyl, and hexavalent phenyl; wherein the trivalent phenyl and trivalent pyridyl groups are each optionally replaced by 1, 2, or 3 groups independently selected from C. 1-6 Substituents of alkyl, halogen, nitro, cyano, aryl, and heteroaryl groups; wherein the tetravalent phenyl, tetravalent pyridyl, and trivalent pyrazolyl groups are each optionally replaced by one or two independently selected from C10. 1-6 Substituents of alkyl, halogen, nitro, cyano, aryl, and heteroaryl groups; wherein the pentavalent phenyl group is optionally selected from C10. 1-6 Substituents include alkyl, halogen, nitro, cyano, aryl, and heteroaryl groups. The polyvalent linker M1 can be selected from:

[0096]

[0097] Appropriately, the multivalent linker M1 is... .

[0098] Sulfonated hydrocarbon ionomers may suitably have ion exchange capacities of less than or equal to about 5 meq / g, appropriately less than or equal to about 4 meq / g, suitably less than or equal to about 3.5 meq / g, for example, less than or equal to about 3 meq / g. Sulfonated hydrocarbon ionomers may suitably have ion exchange capacities of greater than or equal to about 1 meq / g, typically greater than or equal to about 2 meq / g. Ion exchange capacity can be determined using titration. For example, by immersing the membrane in a 1.0 M NaCl solution for 24 hours to determine the ion exchange capacity using Na... + Ion exchange H + Ions can be in acid form (H+) + The membrane is converted to sodium salt form. Then, the exchanged H+ in the solution can be titrated with 0.02N NaOH solution. + Ions. The theoretical ion exchange capacity calculated from the degree of sulfonation can be obtained by the following formula: Ion exchange capacity (meq / g) = ion concentration in mmol / mass of dry membrane at 25°C.

[0099] Sulfonated hydrocarbon ionomers may suitably have a molecular weight of less than or equal to about 25,000 Daltons, for example, less than or equal to about 20,000 Daltons. Sulfonated hydrocarbon ionomers typically have a molecular weight of at least about 10,000 Daltons, for example, at least about 15,000 Daltons. Molecular weight is the weight-average molecular weight as measured using gel permeation chromatography.

[0100] Sulfonated hydrocarbon ionomers can suitably have a content of at least about 1 g / cm³. 3 The density of the dry powder form. Sulfonated hydrocarbon ionomers can suitably have a density less than or equal to about 2 g / cm³. 3 Appropriately less than or equal to approximately 1.5 g / cm³ 3 The density of the dry powder form.

[0101] The λ value of the ion-conducting membrane is less than about 60, suitably less than about 50, more suitably less than about 45, more suitably less than about 35, for example less than about 30. λ is a measure of water absorption rate, and in the case of this invention, it is determined after water absorption at about 80°C, representing the temperature faced during actual use, such as in proton exchange membrane fuel cells, for example in automotive applications. Specifically, λ is the number of moles of water molecules per sulfonate group in the ionomer, and can be measured by measuring the mass of the dried membrane (dried in a vacuum membrane at 100°C) and the mass of the hydrated membrane immediately after immersion in water at 80°C for 24 hours, referred to as m. 水 and m 干燥膜 Then the following equation can be used.

[0102]

[0103] To correct for membranes with reinforcement, the original λ equation should be multiplied by the reciprocal of the ionomer volume fraction, which is obtained by dividing the volume of the dried ionomer by the volume of the dried membrane. The volume of the dried ionomer can be obtained by subtracting the volume of the reinforcement placed in the membrane from the measured volume of the membrane.

[0104]

[0105] The ion-conducting film may suitably have a wet film average domain spacing (Å) of less than or equal to about 39, suitably less than or equal to about 37, more suitably less than or equal to about 34, for example less than or equal to about 32, as determined by small-angle X-ray scattering (SAXS). The ion-conducting film may suitably have a wet film average domain spacing (Å) of at least about 20, as determined by SAXS. The ion-conducting film may suitably have a wet film correlation length (Å) of less than or equal to about 9, typically less than or equal to about 7, for example less than or equal to about 8, as determined by SAXS. The ion-conducting film may suitably have a wet film correlation length (Å) of at least about 1, as determined by SAXS.

[0106] SAXS data were collected using an X-ray source, where detector-to-sample distances of 0.01 and 1 Å were observable. -1 The q range is defined between [a certain value]. Background subtraction for air, capillaries, and / or solvents should be performed before model fitting. Fit the Teubner-Strey model to this region, ensuring a suitable good fit (rejecting chi values ​​greater than 10). 2 (Values). The model provides relevant lengths and domain spacings. These are used to define the polymer structure in a dispersion, solution, or membrane. In this paper, "wet membrane" refers to a membrane immersed in deionized water at 20°C for at least 48 hours, where the membrane is thick enough to provide sufficient scattering for background subtraction. Any dispersion / solution SAXS is completed with sufficient ionomer solids to provide adequate scattering.

[0107]

[0108] The ion-conducting membrane may also include a reinforcing layer comprising a porous polymer material, wherein a sulfonated hydrocarbon ionomer is impregnated within the porous polymer material. The reinforcing layer is typically planar. The porous polymer material may be a fluoropolymer. Porous polymer materials may be selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyethersulfone (PES), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polyimide (PI), polyetherimide (PEI), poly(aryl ether ketone) (PAEK), poly(aryl ether sulfone), poly(phenylene sulfide) (PPS), and polyvinylpyrrolidone (PVP). The porous polymer material may also be expanded polytetrafluoroethylene (ePTFE). The porous polymer material may also include a polymer backbone based on a nitrogen-containing heterocycle. The nitrogen-containing heterocycle may contain a basic functional group. The nitrogen-containing basic functional group may be nitrogen with a lone pair of electrons. The polymer backbone may suitably be derived from polybenzimidazole, polypyridine, polypyrimidine, polybenzothiazole, polyoxadiazole, polyquinoline, polyquinoxaline, polythiadiazole, polytriazole, polyoxazole, polybenzoxazole, polythiazolium, polypyrazole, and derivatives thereof. Suitably, the polymer backbone may be derived from functionalized polyazoles or zwitterionic polyazoles, such as polybenzimidazole, polytriazole, polythiazolium, and polydiazole, and derivatives thereof; most suitable is polybenzimidazole. Those skilled in the art will understand that the polymer backbone may contain more than one type of nitrogen-containing heterocycle, or a mixture of nitrogen-containing heterocycles with other aliphatic or aromatic groups.

[0109] Suitablely, the maximum thickness of the reinforcing layer is 100% of the thickness of the reinforced ion-conducting film, such as a maximum thickness of 90%, 80%, 70%, 60%, or 50% of the thickness of the ion-conducting film. The minimum thickness of the porous polymer material is suitablely 5% of the thickness of the ion-conducting film, such as a minimum thickness of 10%, 15%, 20%, 25%, or 30% of the thickness of the ion-conducting film. Suitablely, the thickness of the porous polymer material in the ion-conducting film can range from 5% to 95% of the thickness of the reinforced ion-conducting film, including extreme values, such as a thickness ranging from 10% to 90% or 20% to 80% of the thickness of the reinforced ion-conducting film, including extreme values.

[0110] The ion-conducting membrane may suitably include more than one reinforcing layer, such as two reinforcing layers, each having a sulfonated hydrocarbon ionomer impregnated in at least one region therein. It should be understood that, in the case of a reinforced ion-conducting membrane having more than one reinforcing layer, the maximum and / or minimum thickness is the sum of the thicknesses of each porous polymer structure. The proportion of the thickness of this porous polymer structure, or each porous polymer structure, to the reinforced ion-conducting membrane can be determined, for example, by scanning electron microscopy (SEM) images of a cross-section of the reinforced ion-conducting membrane after proper drying at 0% relative humidity.

[0111] The thickness of the ion-conducting membrane will depend on its intended use. For example, the ion-conducting membrane in a water electrolyzer will typically be thicker than that in a fuel cell, but this may not always be the case. Suitablely, the ion-conducting membrane has a thickness of at least about 5 micrometers, as determined by scanning electron microscopy (SEM) images of the membrane cross-section analyzed when properly dried at 0% relative humidity. Suitablely, the thickness of the ion-conducting membrane is at least about 6 micrometers, about 7 micrometers, about 8 micrometers, about 9 micrometers, or at least about 10 micrometers. Typically, when properly dried at 0% relative humidity, the thickness of the ion-conducting membrane is less than or equal to about 200 micrometers, such as less than or equal to about 150 micrometers, less than or equal to about 100 micrometers, less than or equal to about 50 micrometers, less than or equal to about 30 micrometers, less than or equal to about 25 micrometers, or less than or equal to about 20 micrometers. Appropriately, when properly dried at 0% relative humidity, the thickness of the ion-conducting film is in the range of about 5 micrometers to about 200 micrometers, about 6 micrometers to about 100 micrometers, about 6 micrometers to about 50 micrometers, about 7 micrometers to about 30 micrometers, or about 8 micrometers to about 20 micrometers, including the end values.

[0112] This document discloses a method for preparing an ion-conducting membrane comprising a sulfonated hydrocarbon ionomer, the method comprising casting a membrane from a mixture of the sulfonated hydrocarbon ionomer and a solvent. The ion-conducting membrane suitably is an ion-conducting membrane as defined herein. The mixture may be in the form of a dispersion, such as a fine suspension or solution of ionomer particles, or may contain elements that dissolve and disperse, i.e., partial dissolution of the ionomer in the solvent. Suitably and advantageously, the membrane is cast from the solvent at ambient temperature, i.e., the casting step does not require the application of heat. For example, the casting temperature may be below about 30°C. The casting temperature may be at least about 15°C, for example at least about 20°C. The casting step can typically be carried out for a time of less than or equal to about 30 minutes, suitably less than or equal to about 15 minutes, more suitably less than or equal to about 10 minutes, for example less than or equal to about 5 minutes. The solvent may suitably include any solvent that forms a membrane having a relevant length as defined herein at ambient temperature, which can be determined by a person skilled in the art using the methods described herein. Specifically, the mixture itself may suitably have a relevant length (Å) of less than or equal to about 9, typically less than or equal to about 7, for example less than or equal to about 8, as determined by SAXS. The mixture may suitably have a relevant length of at least about 1, as determined by SAXS. The solvent may contain an alcohol, typically an alcohol containing 3 or more carbons. Suitably, the alcohol contains no more than 9 atoms, more suitably no more than 8 atoms, and typically no more than 7 carbons. The alcohol may be linear or branched, and is typically linear. For example, the alcohol may be n-hexanol. Mixtures of such solvents may be used. For example, a primary solvent having the properties defined above and which will form a film with the desired SAXS relevant length (which can be tested using the procedures disclosed herein) at ambient temperature may be mixed with one or more additional solvents, typically solvents forming a binary system, for example, where the volume ratio of the primary solvent to one or more additional solvents is in the range of about 0.2:1 or greater, suitably about 0.5:1 or greater, typically about 1:1 or greater, and including end values. Surprisingly and advantageously, this mixture can provide an ion-conducting film with the beneficial properties disclosed herein, but it is beneficial to choose one or more additional solvents that allow it / them to evaporate more quickly and thus reduce the casting time. Therefore, one or more additional solvents will have a higher relative evaporation rate than the primary solvent. Examples of suitable additional solvents include methanol, ethanol, and propanol. In this method, the sulfonated hydrocarbon ionomer is first mixed with the solvent. The mixture typically contains at least about 1% by weight of the sulfonated hydrocarbon ionomer based on the total weight of the mixture. The mixture typically contains no more than about 30% by weight of the sulfonated hydrocarbon ionomer based on the total weight of the mixture. The mixture may suitably have a wet film average domain spacing (Å) of less than or equal to about 39, suitably less than or equal to about 37, more suitably less than or equal to about 34, for example less than or equal to about 32, as determined by small-angle X-ray scattering (SAXS).The mixture may suitably have a wet film average domain spacing (Å) of at least about 20, as determined by SAXS.

[0113] Any suitable casting method can be used, including, for example, spraying, electrospraying, screen printing, rotary screen printing, inkjet printing, brushing, painting, immersion or dip coating, bar coating, pad coating, gravure printing; gap coating techniques, such as blades or doctor blades on rollers (thereby applying the coating onto the substrate and then through the gap between the blade and the support roller); slot die (slit, extrusion) coating (thereby extruding the coating onto the substrate by gravity or under pressure through the slit); metering rod applications, such as coating with Meyer rods and gravure printing. After casting, a drying step is typically performed at a temperature, for example, in the range of about 50°C to about 150°C (inclusive), to form an ion-conductive film. Drying can take, for example, less than about 15 minutes, typically less than about 10 minutes.

[0114] A catalyst-coated membrane is also provided, comprising the ion-conducting membrane of this disclosure, wherein a cathode catalyst layer is applied to a first side of the membrane and / or an anode catalyst layer is applied to a second side of the membrane. The catalyst layer comprises one or more electrocatalysts. The one or more electrocatalysts may independently be finely divided unsupported metal powders or supported catalysts in the form of small nanoparticles dispersed on a conductive granular carbon support. The electrocatalyst metal is suitably selected from:

[0115] (i) Platinum group metals (platinum, palladium, rhodium, ruthenium, iridium and osmium).

[0116] (ii) Gold or silver,

[0117] (iii) Base metals,

[0118] Or an alloy or mixture containing one or more of these metals or their oxides.

[0119] Typically, the electrocatalyst metal is platinum, which can form alloys with other noble or base metals. Base metals are tin or transition metals that are not noble metals. Noble metals are platinum group metals (platinum, palladium, rhodium, ruthenium, iridium, or osmium), gold, or silver. Suitable base metals include copper, cobalt, nickel, zinc, iron, titanium, molybdenum, vanadium, manganese, niobium, tantalum, chromium, and tin. Suitable base metals are nickel, copper, cobalt, and chromium. More suitable base metals are nickel, cobalt, and copper. If the electrocatalyst is a supported catalyst, the loading of metal particles on the carbon support material is appropriately in the range of 10% to 90% by weight of the resulting electrocatalyst, typically 15% to 75% by weight. The exact electrocatalyst used will depend on the reaction it is intended to catalyze, and its selection is within the capabilities of a person skilled in the art.

[0120] The catalyst layer will typically contain an ionomer, which may be a perfluorosulfonic acid ionomer. Alternatively, the ionomer may be a sulfonated hydrocarbon ionomer as defined herein. The catalyst layer may also contain additional components. Such additional components include, but are not limited to, catalysts that promote oxygen evolution and are therefore beneficial in cell reversal conditions and high potential shifts, or hydrogen peroxide decomposition catalysts. Examples of such catalysts and any other additives suitable for inclusion in the catalyst layer will be known to those skilled in the art.

[0121] A membrane electrode assembly is also provided, comprising the ion-conducting membrane of this disclosure and a gas diffusion electrode and / or a porous transport layer on a first and / or second surface of the ion-conducting membrane. A membrane electrode assembly is also provided, comprising a catalyst-coated ion-conducting membrane and a gas diffusion layer or porous transport layer present on at least one catalyst layer. The anode and cathode gas diffusion layers are suitably based on conventional gas diffusion substrates. Typical substrates include nonwoven paper or mesh comprising a carbon fiber web and a thermosetting resin binder (e.g., TGP-H series carbon fiber paper from Toray Industries Inc., Japan; H2315 series from Freudenberg FCCT KG, Germany; or Sigrette from SGL Technologies GmbH, Germany). ® Series, or AvCarb from Ballard Power Systems Inc. ® (Series), or woven carbon cloth. Before being incorporated into the membrane electrode assembly, carbon paper, fiber mesh, or cloth may undergo further treatment to make it more wettable (hydrophilic) or more waterproof (hydrophobic). The nature of any treatment will depend on the type of fuel cell and the operating conditions to be used. The substrate can be made more wettable by impregnating the substrate with a material (such as amorphous carbon black) from a liquid suspension, or more hydrophobic by impregnating the porous structure of the substrate with a colloidal suspension of a polymer (such as PTFE or FEP), followed by drying and heating above the melting point of the polymer. For applications such as PEMFCs, a microporous layer can also be applied to a gas diffusion substrate on the surface that will contact the catalyst layer. The microporous layer typically comprises a mixture of carbon black and a polymer (such as polytetrafluoroethylene (PTFE)). Porous transport layers are suitably based on conventional porous transport substrates, such as titanium mesh.

[0122] An electrochemical device is also provided, comprising the ion-conducting membrane of this disclosure, a membrane coated with a catalyst, or a membrane electrode assembly. The electrochemical device can be a fuel cell, such as a proton exchange membrane fuel cell. The electrochemical device can also be an electrolyzer, such as a water electrolyzer. Example membrane synthesis

[0123] The repeating units with formula IB and hydrophobic repeating units, the ion exchange capacity (IEC) in the range of 2.8 meq / g to 3.1 meq / g, and 1.2 g / cm³ are used. 3 Sulfonated phenylened polyphenylene ionomers of a certain density were dispersed in vials of n-alcohol. All dispersible polyphenylene ionomers of n-alcohol, MeOH, EtOH, nPrOH, nBuOH, and nHexOH were dispersed at a concentration of up to 12.33% by weight on a roller bed at room temperature at 60 RPM for at least 24 hours.

[0124] Using a Baker coater with a 200-micron set gap, the ionomer solvent mixture is cast onto a benchtop film coater. The hydrocarbon film is cast, producing a 200-micron wet film, which is then air-dried at 20°C to approximately 13 (±2) microns of dry hydrocarbon film. Once air-dried, the film is placed in a 100°C oven for 5 minutes to remove any residual solvent. At this stage, the film can be cut and removed from the backing.

[0125] Example 1 = Casting from MeOH

[0126] Example 2 = Casting from EtOH

[0127] Example 3: Casting from nPrOH

[0128] Example 4: Casting from nBuOH

[0129] Example 5: nHexOH casting

[0130] Example 6: Casting from a 1:1 volume of MeOH:nPrOH

[0131] Example 7: Casting from a 1:1 volume of MeOH:nBuOH Quality and dimensional change testing

[0132] Measure the dimensions and mass of the cut membrane (ambient conditions), then immerse the membrane back in water at 80°C for 24 hours (wet condition). During this time, the membrane swells. After 24 hours, remove them and measure the mass and dimensions again. Place the wet membrane in a vacuum oven at 100°C for 24 hours (dry condition). After drying again, measure the new mass and dimensions. During this test, an ideal membrane will exhibit minimal changes in mass and dimensions between the wet and dry conditions, while maintaining similar mass and dimensions between ambient and dry conditions.

[0133] Figure 1 As shown, the mass change between the dry and wet states decreases with increasing chain length of the cast alcohol, with Example 5 demonstrating particularly advantageous properties. Figure 2This trend is further demonstrated, and it is also shown that the membrane has similar quality between ambient and dry conditions, which is advantageous.

[0134] Figure 4 As shown, during wet conditions, swelling decreases in lateral, in-plane dimensions as the chain length of the cast alcohol increases. Example 5 demonstrates a particularly advantageous property in which the long alcohol cast film does not become too thin during wet cycling, thereby increasing the durability of these films. λ calculation

[0135] λ is the number of water molecules per sulfonate group in the ionomer, and is measured by measuring the mass of the dried membrane (dried in a vacuum membrane at 100°C) and the mass of the hydrated membrane immediately after immersion in water at 80°C for 24 hours, and is referred to as m. 水 and m 干燥膜 Then the following equation can be used.

[0136]

[0137] Figure 3 The results show that λ decreases with increasing chain length of the casting solvent, with Example 5 exhibiting a particularly surprising value, and providing a membrane that can effectively regulate water during operation, thus producing a membrane with surprising durability. Furthermore, Figure 3 Mixtures of solvents, such as those used in Examples 6 and 7, are shown to produce films in which the water absorption properties are controlled by the solvent providing the most favorable λ. Therefore, mixtures of solvents can be used, wherein one solvent is selected to provide the optimal λ, and a second solvent is selected for greater volatility and improved casting time. Small-angle X-ray scattering (SAXS) measurement

[0138] SAXS data were collected using an X-ray source, where detector-to-sample distances of 0.01 and 1 Å were observable. -1 The q range is defined between [a certain value]. Background subtraction for air, capillaries, and / or solvents should be performed before model fitting. Fit the Teubner-Strey model to this region, ensuring a suitable good fit (rejecting chi values ​​greater than 10). 2 (Value). The model provides relevant lengths and domain spacings. These are used to define the polymeric structure in a dispersion, solution, or membrane. In this paper, "wet membrane" refers to a membrane immersed in deionized water at 20°C for at least 48 hours, where the membrane is thick enough to provide sufficient scattering for background subtraction. Any dispersion / solution SAXS is completed with sufficient ionomer solids to provide adequate scattering.

[0139]

[0140] Figure 6 The results show that the average wet film domain spacing (Å) (d) and wet film correlation length (Å) (xi) decrease with increasing chain length of the cast alcohol, and subsequently, the lower average wet film domain spacing (Å) and wet film correlation length (Å) are correlated with a decreasing λ. Example 5 illustrates particularly advantageous properties. All these correlations are... Figure 7 As shown in the image.

Claims

1. An ion-conducting membrane comprising a sulfonated hydrocarbon ionomer, wherein the ion-conducting membrane has a λ value of less than about 60.

2. The ion-conducting film according to claim 1, wherein the ion-conducting film has a wet film average domain spacing (Å) of less than or equal to about 34, as determined by small-angle X-ray scattering.

3. The ion-conducting film according to claim 1 or claim 2, wherein the ion-conducting film has a wet film correlation length (Å) of less than or equal to about 9, as determined by small-angle X-ray scattering.

4. The ion-conducting membrane according to any of the preceding claims, wherein the sulfonated hydrocarbon ionomer is selected from poly(arylene ether), poly(arylene ether ketone), poly(arylene sulfone), poly(imide), poly(benzimidazole), polyphenylene, and sulfonated derivatives of phenylenediphenylene.

5. The ion-conducting membrane according to any of the preceding claims, wherein the sulfonated hydrocarbon ionomer has an ion exchange capacity of less than or equal to about 5 meq / g.

6. The ion-conducting membrane according to any of the preceding claims, further comprising a reinforcing layer comprising a porous polymer material, wherein the ionomer is impregnated within the porous polymer material.

7. The ion-conducting membrane according to claim 6, wherein the ion-conducting membrane has a λ value of less than about 30.

8. A catalyst-coated membrane for use in a fuel cell or water electrolyzer, said catalyst-coated membrane comprising an ion-conducting membrane according to any one of the preceding claims, wherein a cathode catalyst layer is applied to a first side of the membrane and / or an anode catalyst layer is applied to a second side of the membrane.

9. The catalyst-coated membrane according to claim 8, wherein the catalyst layer comprises a perfluorosulfonic acid ionomer.

10. The catalyst-coated membrane according to claim 9, wherein the catalyst layer comprises a sulfonated hydrocarbon ionomer.

11. A membrane electrode assembly for a fuel cell or a water electrolyzer, the membrane electrode assembly comprising (i) an ion-conducting membrane according to any one of claims 1 to 7; or (ii) a membrane coated with a catalyst according to any one of claims 8 to 10; and at least one of a gas diffusion layer or a porous transport layer.

12. A water electrolyzer or fuel cell, said water electrolyzer or fuel cell comprising a membrane coated with a catalyst according to any one of claims 8 to 10 or a membrane electrode assembly according to claim 11.

13. A method for preparing an ion-conducting membrane according to any one of claims 1 to 7, the method comprising casting the membrane from a mixture of a sulfonated hydrocarbon ionomer and a solvent.

14. The method of claim 13, wherein the mixture has a correlation length (Å) of less than or equal to about 9, as determined by small-angle X-ray scattering.

15. The method of claim 13 or claim 14, wherein the solvent comprises an alcohol having three or more carbon atoms.

16. The method according to any one of claims 13 to 15, wherein the solvent comprises a primary solvent and a secondary solvent.

17. The method according to any one of claims 13 to 16, wherein the casting step is performed at ambient temperature.

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