Application of organic acid compound, metal organic complex and durable proton exchange membrane prepared from metal organic complex

Abstract

The invention relates to an application of an organic acid compound as a durability additive. The organic acid compound is selected from compounds of the following formula I: # imgabs0 #, wherein Cy is a cyclic compound group and A is an acid group. The invention also discloses a proton exchange membrane containing the organic acid compound, the organic acid compound enables the proton exchange membrane to have improved durability, the service life can be prolonged, and the proton exchange membrane is suitable for preparing a membrane electrode assembly, a fuel cell, a water electrolyser, hydrogen production equipment, a flow battery and the like.

Description

Technical Field

[0001] The present invention relates to the field of new energy technology, and in particular to a proton exchange membrane. Background Art

[0002] Fossil fuel is a non-renewable energy source and contains a large amount of chemical elements that can cause environmental pollution, such as sulfur and nitrogen. The extensive use of fossil fuels has caused serious energy crises and environmental pollution problems. It is of great significance to find a new renewable clean energy to replace fossil energy.

[0003] Hydrogen fuel cells and electrolyzers for hydrogen production by water electrolysis contain an important component - proton exchange membrane (PEM), which is used to block the cross-linking of hydrogen and oxygen. The PEM currently used in hydrogen fuel cells and PEM water electrolyzers are all perfluorosulfonic acid resin (PFSA) membranes. During the operation of hydrogen fuel cells and PEM water electrolyzers, hydrogen peroxide is produced, which in turn generates hydroxyl radicals and hydrogen peroxide radicals. These free radicals will attack some unstable groups and non-fluorine atoms in PFSA molecules, such as sulfonic acid groups and ether bonds in resin molecules, and eventually lead to membrane degradation, thereby affecting the performance, life and safety of fuel cells and PEM water electrolyzers.

[0004] Therefore, extending the service life of proton exchange membranes is an urgent issue to be addressed. Summary of the invention

[0005] To this end, the present invention provides the following technical solution, which can effectively extend the service life of the proton exchange membrane.

[0006] A first aspect of the present invention provides a use of an organic acid compound as a durability additive.

[0007] The organic acid compound of the present invention is selected from the following compounds of formula I:

[0008]

[0009] in:

[0010] Cy is a C containing at least one heteroatom 5-15 A cyclic compound group, wherein the heteroatom is selected from nitrogen, oxygen or sulfur;

[0011] m is any integer from 1 to 6;

[0012] Each L may be the same or different and is independently selected from a chemical bond or C 1-10 unsubstituted or replaced by R s Substituted alkyl, the R s Selected from halogen, C 1-6 Alkyl, C 1-6 Alkyloxy;

[0013] A is an acid group, each A can be the same or different, and each is independently selected from an inorganic acid group or an organic acid group;

[0014] n is any integer from 0 to 12;

[0015] Each R can be the same or different, and each is independently H, C 1-12 unsubstituted or substituted by R s substituted alkyl group.

[0016] In a preferred embodiment of the present invention, Cy in the compound of formula I is a cyclic compound group containing at least 1 heteroatom, and at least one of the heteroatoms is nitrogen. 5-15 Preferably, the cyclic compound group containing at least 1 heteroatom is a heteroaryl group or a nitrogen-containing bicyclic group of C

[0017] Preferably, the cyclic compound group containing at least 1 heteroatom is a heteroaryl group of C 5-15 or a nitrogen-containing bicyclic group of C 5-10 Preferably, the heteroaryl group of C 5-15 is selected from pyrrole, thiazole, oxazole, imidazole, pyrazole, pyridine, or pyrimidine.

[0018] Preferably, the nitrogen-containing bicyclic group of C 5-10 is selected from benzopyrrole group, benzothiazole group, benzoxazole group, benzimidazole group, benzopyrazole group, benzopyridine group, or benzopyrimidine group.

[0019] Preferably, L is a chemical bond or an alkyl group of C 1-4

[0020] Preferably, A is selected from carboxylic acid, phosphoric acid, hypophosphorous acid, phosphorous acid, sulfinic acid, sulfonic acid, or boric acid group; preferably, A is selected from -SO3H, -COOH, -PO3H2.

[0021]

[0022] In a preferred embodiment of the present invention, the compound of formula I is selected from the following compounds of formula II:

[0023]

[0024]

[0025] wherein, X1 to X9 can be the same or different, and each is independently selected from C, N, O, S, and at least one of X1 to X9 is a nitrogen atom, preferably at least two or more of X1 to X9 are nitrogen atoms, more preferably two of X1 to X9 are nitrogen atoms;

[0025] m is any integer from 1 to 6, preferably any integer from 1 to 3, more preferably any integer from 1 to 2;

[0026] -L1-SO3H can be substituted on any one of the atoms X1 to X9, and each L1 can be the same or different and is independently a chemical bond or a C 1-4 alkyl group, preferably a chemical bond or a methylene group;

[0027] n is any integer from 0 to 6;

[0028] R1 can be substituted on any one of the atoms X1 to X9, and each R1 can be the same or different and is independently selected from H, C 1-4 alkyl group, preferably R1 is H, methyl or ethyl.

[0029] In a preferred embodiment of the present invention, the compound of formula I is selected from the compounds of formula III as follows:

[0030]

[0031] wherein, -L2-A can be substituted at any position on the benzimidazole ring, and each L2 can be the same or different and is independently a chemical bond or a C 1-4 alkyl group; preferably L2 is a chemical bond or a methylene group; most preferably, L2 is a chemical bond;

[0032] The definitions of A, n, and m are as described in any of the previous embodiments.

[0033] R2 can be substituted at any position on the benzimidazole ring, and each R2 can be the same or different and is independently selected from H, C 1-4 alkyl group, preferably R2 is H, methyl or ethyl.

[0034] In a second aspect of the present invention, there is provided a metal-organic complex comprising (i) an organic ligand comprising the organic acid compound or its ionized product of the present invention as described above, and (ii) a metal component.

[0035] Wherein, the metal component is a metal ion, and the metal component is preferably selected from at least one of the metal ions corresponding to Ce, Mn, Pd, Ag, Au, Pt, W, Co, Rh. Or the metal component is selected from at least one of the metal ions corresponding to Ce and Mn.

[0036] Preferably, the molar ratio of the organic ligand to the metal element in the metal component in the metal-organic complex is 1:6 - 6:1, more preferably 1:2 - 2:1.

[0037] In a third aspect of the present invention, there is provided the use of the organic acid compound or the metal-organic complex of the present invention as described above in the preparation of a proton exchange membrane.

[0038] In a fourth aspect of the present invention, there is provided a proton exchange membrane containing the organic acid compound or the metal-organic complex of the present invention as described above.

[0039] Among them, the content of the organic acid compound in the proton exchange membrane is 0.001-10 wt%, preferably 0.01-5 wt%.

[0040] The fifth aspect of the present invention provides the use of the aforementioned organic acid compound or metal-organic complex of the present invention in the preparation of a membrane electrode assembly, a fuel cell, a water electrolyzer, a hydrogen production device, and a flow battery. Detailed Description of Specific Embodiments

[0041] In the following description, numerous specific details are given to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, some well-known technical features are not described to avoid confusion with the present invention.

[0042] The following describes the implementation of the present invention in detail in combination with the term definitions:

[0043] I Organic Acid Compound

[0044] In one embodiment of the present invention, the organic acid compound comprises a compound of Formula I:

[0045]

[0046] Wherein:

[0047] Cy is a cyclic compound group containing at least 1 heteroatom selected from nitrogen, oxygen or sulfur. 5-15 The heteroatom is selected from nitrogen, oxygen or sulfur.

[0048] In one embodiment, Cy is a cyclic compound group containing at least 1 heteroatom, and at least one of the heteroatoms is nitrogen. 5-15 The heteroatom is at least one nitrogen.

[0049] Preferably, Cy is a cyclic compound group containing at least 1 heteroatom, and at least one of the heteroatoms is nitrogen. 5-14 C 5-10 C 5-6 C 8-9 C 9-10 The heteroatom is at least one nitrogen. Wherein, Cy can be a heterocycloalkyl group, a heteroaryl group, or a bicyclic, polycyclic or fused ring group composed of at least one cycloalkyl group and / or at least one aryl group.

[0050] In one embodiment, the cyclic compound group containing at least 1 heteroatom is a heteroaryl group or a nitrogen-containing bicyclic group. 5-15 The cyclic compound group containing at least 1 heteroatom is a heteroaryl group or a nitrogen-containing bicyclic group. 5-10 The cyclic compound group containing at least 1 heteroatom is a heteroaryl group or a nitrogen-containing bicyclic group. 5-15 The cyclic compound group containing at least 1 heteroatom is a heteroaryl group or a nitrogen-containing bicyclic group.

[0051] When Cy is a heteroaryl group of C 5-10 , Cy contains a C that contains at least 1 heteroatom 5-10 , or C 5-6 , or C 8-9 heteroaryl group, and at least one of the heteroatoms is nitrogen. Preferably, Cy contains at least 2, or 3, or more nitrogen atoms, and may also contain at least 1, 2, or more oxygen atoms and / or sulfur atoms.

[0052] For example, Cy may be selected from the following C 5-10 heteroaryl groups:

[0053]

[0054] Preferably, Cy is selected from pyrrole, thiazole, oxazole, imidazole, pyrazole, pyridine, or pyrimidine groups.

[0055] When Cy is a nitrogen-containing bicyclic group of C 5-15 , the nitrogen-containing bicyclic group is selected from a C that contains at least 1 heteroatom 5-14 , or C 5-6 , or C 8-9 , or C 9-10 nitrogen-containing bicyclic group, and at least one of the heteroatoms is nitrogen. Preferably, Cy contains at least 2, or 3, or more nitrogen atoms, and may also contain at least 1, 2, or more oxygen atoms and / or sulfur atoms.

[0056] For example, Cy may be selected from the following C 5-15 nitrogen-containing bicyclic groups:

[0057]

[0058] Preferably, Cy is selected from benzopyrrole group, benzothiazole group, benzoxazole group, benzimidazole group, benzopyrazole group, benzopyridine group, or benzopyrimidine group.

[0059] m is any integer from 1 to 6, and can be 1, 2, 3, 4, 5, or 6. Preferably, m is 1, 2, or 3. Most preferably, m is 1 or 2.

[0060] Each L may be the same or different and is independently a chemical bond or an unsubstituted or R 1-10 -substituted alkyl group of C s , where R s is selected from halogen, C 1-6 alkyl, C 1-6 alkyloxy.

[0061] Preferably, L is a chemical bond or an alkyl group of C 1-6 . If L is C 1-6When L is an alkyl group, it can be methylene, ethylene, propylene, butylene, pentylene, or hexylene. Most preferably, L is C 1-4 alkyl groups such as methylene, ethylene, propylene, and butylene.

[0062] A is an acid group, and each A can be the same or different and is independently selected from inorganic acid groups or organic acid groups such as carboxylic acid, phosphoric acid, hypophosphorous acid, phosphorous acid, sulfinic acid, sulfonic acid, or boric acid groups. Preferably, A is selected from -SO3H, -COOH, -PO3H2.

[0063] n is any integer from 0 to 12 and can be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12. Preferably, n is 0, 1, 2, 3, 4, 5, or 6.

[0064] Each R can be the same or different and is independently H, C 1-12 or C 1-6 unsubstituted or R s substituted alkyl groups, and the definition of R s is as described above. When R is an alkyl group, it can be methyl, ethyl, propyl, butyl, pentyl, or hexyl.

[0065] In another embodiment of the present invention, the compound of formula I is selected from the following compounds of formula II:

[0066]

[0067] wherein X1 to X9 can be the same or different and are independently selected from C, N, O, S, and at least one of X1 to X9 is a nitrogen atom. Preferably, at least two or more of X1 to X9 are nitrogen atoms, and more preferably, two of X1 to X9 are nitrogen atoms.

[0068] As an example, the group of formula II contains a group derived from the following heteroaromatic ring:

[0069]

[0070] The definition of m is as described above.

[0071] -L1-SO3H can be substituted on any atom of X1 to X9, and each L1 can be the same or different and is independently a chemical bond or C 1-4 alkyl groups. Preferably, L1 is a chemical bond or methylene.

[0072] n is any integer from 0 to 6 and can be 0, 1, 2, 3, 4, 5, or 6.

[0073] R1 can be substituted on any atom of X1 to X9, and each R1 can be the same or different and is independently H, C 1-4An alkyl group, preferably H, methyl or ethyl.

[0074] In another embodiment of the present invention, the compound of formula I is selected from the compounds of formula III as follows:

[0075]

[0076] Wherein, -L2-A can be substituted at any position on the benzimidazole ring, each L2 can be the same or different, and each is independently a chemical bond or C 1-4 An alkyl group. Preferably, L2 is a chemical bond or methylene. Most preferably, L2 is a chemical bond.

[0077] The definitions of A, n, and m are as described in any of the previous embodiments.

[0078] R2 can be substituted at any position on the benzimidazole ring, each R2 can be the same or different, and each is independently H, C 1-4 A substituted or unsubstituted alkyl group, preferably H, methyl or ethyl.

[0079] In a specific embodiment of the present invention, the compound of formula I is:

[0080]

[0081] II Durability additive

[0082] In one embodiment of the present invention, the organic acid compound of the present invention is suitable as a durability additive in a proton exchange membrane, and can improve the lifespan when the proton exchange membrane is applied to devices such as fuel cells.

[0083] "Durability additive" means that, compared with the membrane without adding the above durability additive, the proton exchange membrane added with the durability additive has less degradation or dissolution, or improved durability and lifespan.

[0084] After adding the durability additive of the present invention, compared with the membrane without adding the above durability additive, the durability of the proton exchange membrane added with the durability additive, such as service life, dissolution resistance, antioxidant property, or degradation resistance performance, is improved by 1-1000%, 10-900%, 20-800%, 50-700%, 100-500%, or 200-300%.

[0085] Preferably, after adding the durability additive of the present invention, compared with the membrane without adding the above durability additive, the proton exchange membrane added with the durability additive has a reduced ion (such as fluoride ion) dissolution amount of 1-1000%, 10-500%, 20-300%, 50-200%, or 75-120% after normal use for the same time.

[0086] III Metal-organic complexes

[0087] In one embodiment of the present invention, the organic acid compound of the present invention can be connected to a metal component to prepare a metal-organic complex as a durability additive for a proton exchange membrane.

[0088] In one embodiment of the present invention, the metal-organic complex of the present invention comprises: (i) an organic ligand, the organic ligand comprising the organic acid compound or its ionized product according to any one of claims 1-2, and (ii) a metal component.

[0089] Preferably, the ionized product of the organic acid compound is an anion with a valence of 1-m of the organic acid compound, where m is defined as described above.

[0090] In one embodiment of the present invention, the metal component can be a metal ion.

[0091] Preferably, the metal component is a metal ion corresponding to Ce, Mn, Pd, Ag, Au, Pt, W, Co, Rh, such as a monovalent, divalent, trivalent, tetravalent, pentavalent or hexavalent metal ion.

[0092] Preferably, the metal component is a metal ion corresponding to Ce, Mn, such as a monovalent, divalent, trivalent, tetravalent metal ion.

[0093] The metal-organic complex of the present invention can be formed by connecting the organic acid compound or its ionized product of the present invention and the metal component through chemical bonds, ionic bonds, covalent bonds, metallic bonds, coordination bonds, hydrogen bonds or other intermolecular or intramolecular interactions.

[0094] Preferably, the metal-organic complex of the present invention is a complex formed by an organic acid compound and / or its anion and a metal cation through ionic bonds and / or coordination bonds.

[0095] In one embodiment of the present invention, the molar ratio of the organic ligand to the metal element in the metal component in the metal-organic complex is 1:6 - 6:1, 1:5 - 5:1, 1:4 - 4:1, 1:3 - 3:1, 1:2 - 2:1, or 1:1.

[0096] Preferably, the metal-organic complex of the present invention is prepared by reacting the organic acid compound of the present invention with a salt containing a metal cation.

[0097] IV Proton exchange membrane and its applications

[0098] In one embodiment of the present invention, the organic acid compound of the present invention is particularly suitable as a durability additive for preparing a proton exchange membrane.

[0099] Preferably, the proton exchange membrane contains 0.001-10 wt%, 0.002-8 wt%, 0.005-6 wt%, or 0.01-5 wt%, 0.05-2 wt%, 0.1-1 wt%, or 0.2-0.5 wt% of the organic acid compound of the present invention.

[0100] Preferably, the thickness of the proton exchange membrane is 4-250 μm, 5-150 μm, 6-100 μm, 8-80 μm.

[0101] In one embodiment of the present invention, the proton exchange membrane of the present invention comprises:

[0102] Perfluorosulfonic acid resin 10-99.999 wt%, or 30-99 wt%, or 50-95 wt%, or 70-90 wt%;

[0103] The organic acid compound of the present invention 0.001-10 wt%, or 0.001-5 wt%;

[0104] Optional reinforcing material 1-90 wt%, or 2-60 wt%, or 5-40 wt%.

[0105] In another embodiment of the present invention, the proton exchange membrane of the present invention comprises:

[0106] Perfluorosulfonic acid resin 10-99.999 wt%, or 30-99 wt%, or 50-95 wt%, or 70-90 wt%;

[0107] The metal-organic complex of the present invention 0.001-20 wt%, or 0.001-10 wt%, or 0.001-5 wt%;

[0108] Optional reinforcing material 1-90 wt%, or 2-60 wt%, or 5-40 wt%.

[0109] The proton exchange membrane of the present invention can be prepared by any method. For example, it can be prepared by solution coating or solution casting.

[0110] In another embodiment of the present invention, the proton exchange membrane of the present invention can be used in the preparation of membrane electrode assemblies, fuel cells, water electrolyzers, hydrogen production equipment, and flow batteries.

[0111] The present invention will be described in detail below with specific examples.

[0112] I Proton Exchange Membrane Application Examples

[0113] Comparative Example 1

[0114] Using perfluorosulfonic acid resin (Nafion D2020CS) with a solid content of 20% as the coating solution, proton exchange membranes (PEMs) with thicknesses of 12 μm, 50 μm, and 80 μm were prepared by solution casting, denoted as N-12, N-50, and N-80, respectively.

[0115] Comparative Example 2

[0116] Using perfluorosulfonic acid resin (Nafion D2020CS) with a solid content of as the coating solution and expanded polytetrafluoroethylene (ePTFE) as the reinforcing layer, PEMs with reinforcing layers and thicknesses of 12 μm, 50 μm, and 80 μm were prepared by a coating compounding machine, denoted as NP-12, NP-50, and NP-80, respectively. The thickness of the reinforcing layer accounts for 30% of the overall membrane thickness.

[0117] Comparative Example 3

[0118] CeO2 was added to the Nafion D2020CS perfluorosulfonic acid resin dispersion with a solid content of 20% to prepare a coating solution, where the ratio of CeO2 to the resin was 5:1000. Proton exchange membranes (PEMs) with thicknesses of 12 μm, 50 μm, and 80 μm were prepared by solution casting, denoted as NC-12, NC-50, and NC-80, respectively.

[0119] Comparative Example 4

[0120] MnO2 was added to the Nafion D2020CS perfluorosulfonic acid resin dispersion with a solid content of 20% to prepare a coating solution, where the ratio of MnO2 to the resin was 5:1000; with ePTFE as the reinforcing layer, PEMs with reinforcing layers and thicknesses of 12 μm, 50 μm, and 80 μm were prepared by a coating compounding machine, denoted as NMP-12, NMP-50, and NMP-80, respectively; the proportions of the thickness of the reinforcing layer in the membrane thickness were 30%, 10%, and 8%, respectively.

[0121] Example 1

[0122] 4-Imidazoleacrylic acid was added to the Nafion D2020CS perfluorosulfonic acid resin dispersion with a solid content of 20% to make the mass ratio of the resin to 4-imidazoleacrylic acid 1000:5, obtaining a coating solution; then PEMs with thicknesses of 12 μm, 50 μm, and 80 μm were prepared by solution casting, denoted as NIAC-12, NIAC-50, and NIAC-80, respectively.

[0123] Example 2

[0124] 1H-imidazole-4-carboxylic acid was added to a Nafion D2020CS perfluorosulfonic acid resin dispersion with a solid content of 20%, such that the mass ratio of the resin to 1H-imidazole-4-carboxylic acid was 1000:5, to obtain a coating solution; then PEMs with thicknesses of 12 μm, 50 μm, and 80 μm were respectively prepared by solution casting, and were denoted as NICA-12, NICA-50, and NICA-80.

[0125] Example 3

[0126] 2-Methyl-3H-benzimidazole-5-carboxylic acid was added to a Nafion D2020CS perfluorosulfonic acid resin dispersion with a solid content of 20%, such that the mass ratio of the resin to 2-methyl-3H-benzimidazole-5-carboxylic acid was 1000:5, to obtain a coating solution; then PEMs with thicknesses of 12 μm, 50 μm, and 80 μm were respectively prepared by solution casting, and were denoted as NMBICA-12, NMBICA-50, and NMBICA-80.

[0127] Example 4

[0128] Benzimidazole-5,6-dicarboxylic acid was added to a Nafion D2020CS perfluorosulfonic acid resin dispersion with a solid content of 20%, such that the mass ratio of the resin to benzimidazole-5,6-dicarboxylic acid was 1000:5, to obtain a coating solution; then PEMs with thicknesses of 12 μm, 50 μm, and 80 μm were respectively prepared by solution casting, and were denoted as NBIDCA-12, NBIDCA-50, and NBIDCA-80.

[0129] Example 5

[0130] 2-Methylbenzimidazole-5-sulfonic acid was added to a Nafion D2020CS perfluorosulfonic acid resin dispersion with a solid content of 20%, such that the mass ratio of the resin to 2-methylbenzimidazole-5-sulfonic acid was 1000:5, to obtain a coating solution; then PEMs with thicknesses of 12 μm, 50 μm, and 80 μm were respectively prepared by solution casting, and were denoted as NMBIS-12, NMBIS-50, and NMBIS-80.

[0131] Example 6

[0132] The coating solution composition was the same as that of Example 3.

[0133] Using ePTFE as the reinforcing layer, PEMs with reinforcing layers having thicknesses of 12 μm, 50 μm, and 80 μm were respectively prepared by a coating laminator, and were denoted as NMBICAP-12, NMBICAP-50, and NMBICAP-80. The proportion of the thickness of the reinforcing layer in the film thickness was 30%, 10%, and 8% respectively.

[0134] Example 7

[0135] Take 100 g of deionized water, add 9.55 g of Ce(NH4)2(NO3)6 thereto, adjust the pH value to 1.0 with nitric acid, add 3.9 g of 1H-imidazole-4-carboxylic acid, and mix well. Transfer the above solution to a sealed reaction kettle, raise the temperature to 80 °C, and react for 4 h to obtain a colloid of the complex of 1H-imidazole-4-carboxylic acid and Ce, denoted as the complex of Ce and 1H-imidazole-4-carboxylic acid is denoted as Ce-ICA, and its molecular formula is CeC8H6N4O4.

[0136] Example 8

[0137] Add Ce-ICA to the Nafion D2020CS perfluorosulfonic acid resin dispersion with a solid content of 20% so that the mass ratio of the resin to Ce-ICA is 1000:5 to prepare a coating solution; then PEMs with thicknesses of 12 μm, 50 μm, and 80 μm are respectively prepared by solution casting, and are denoted as NCeICA-12, NCeICA-50, and NCeICA-80.

[0138] Example 9

[0139] Add 1H-imidazole-4-carboxylic acid to the Nafion D2020CS perfluorosulfonic acid resin dispersion with a solid content of 20% so that the mass ratio of the resin to 1H-imidazole-4-carboxylic acid is 1000:10 to prepare a coating solution; then PEMs with thicknesses of 12 μm, 50 μm, and 80 μm are respectively prepared by solution casting, and are denoted as NICA2-12, NICA2-50, and NICA2-80.

[0140] II Test Example

[0141] Example 10

[0142] Take 30% hydrogen peroxide, add 20 ppm of ferrous sulfate thereto, and prepare a Fenton reagent.

[0143] Take 0.08 g of the PEMs prepared in Comparative Examples 1-4, Examples 1-6, and Examples 8-9 respectively, and then immerse them in 45 ml of the above Fenton reagent respectively. After 4 h of water bath at 80 °C, take out the PEMs, wash them, detect the fluoride ion concentration of the Fenton reagent, and calculate the fluoride ion dissolution amount of the PEM in 4 h; then soak the PEMs in 45 ml of fresh Fenton reagent again respectively. After 4 h of water bath at 80 °C, take out the PEMs, wash them, detect the fluoride ion concentration of the Fenton reagent, and calculate the fluoride ion dissolution amount in this 4 h, and add the fluoride ion dissolution amount in the previous 4 h to obtain the fluoride ion dissolution amount in 8 h; repeat the above steps twice to obtain the fluoride ion dissolution amounts in 12 h and 16 h respectively. According to the detected fluoride ion concentration in the Fenton reagent after the reaction, calculate the fluoride ion dissolution amount of the membrane material. The calculation formula is as follows:

[0144] Fluoride ion dissolution amount = (fluoride ion concentration of Fenton reagent after reaction × volume of Fenton reagent after reaction) / membrane material mass

[0145] The measured results are shown in Table 1 as follows.

[0146] Example 11

[0147] The membrane materials of Comparative Examples 1-4, Examples 1-6 and Examples 8-9 were cut into pieces, and the proton conductivity was tested under the conditions of 85 °C and RH 50% according to the method of GB / T 200242.3-2022. The measured results are shown in Table 2 as follows.

[0148] Table 2 Fluoride ion dissolution amount in the Fenton experiment of each membrane material

[0149]

[0150]

[0151] It can be seen from the above table of comparative examples and examples that:

[0152] (1) After adding the organic acid compound or metal-organic complex of the present invention, the proton conductivity of the proton exchange membrane basically remains stable. Therefore, the durability additive of the present invention will not affect the normal use performance of the proton exchange membrane.

[0153] (2) After adding the organic acid compound or metal-organic complex of the present invention within the content range of the present invention, the fluoride ion dissolution amount of the proton exchange membrane under the action of Fenton reagent is significantly reduced. Therefore, the organic acid compound or metal-organic complex of the present invention can be used as a durability additive to improve the durability of the proton exchange membrane.

[0154] For the above-mentioned examples, all technical solutions within the idea of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, several improvements and modifications made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. Use of an organic acid compound as a durability additive, wherein the organic acid compound is selected from compounds of formula I as follows: Wherein: Cy is a cyclic compound group of C containing at least 1 heteroatom, and the heteroatom is selected from nitrogen, oxygen or sulfur; 5-15 ​ m is any integer from 1 to 6; Each L can be the same or different and is independently selected from a chemical bond or an unsubstituted or R 1-10 -substituted alkyl group, where the R s is selected from halogen, C s alkyl, C 1-6 alkyloxy; 1-6 ​ A is an acid group, and each A can be the same or different and is independently selected from an inorganic acid group or an organic acid group; n is any integer from 0 to 12; Each R can be the same or different and is independently H, C 1-12 unsubstituted or substituted by R s substituted alkyl group.

2. Use according to claim 1, wherein Cy is a cyclic compound group of C containing at least 1 heteroatom 5-15 , and at least one of the heteroatoms is nitrogen; Preferably, the cyclic compound group containing at least 1 heteroatom is a heteroaryl group of C 5-15 or an azabicyclic group of C 5-10 ; 5-15 ​ Preferably, the C 5-10 heteroaryl group is selected from pyrrole, thiazole, oxazole, imidazole, pyrazole, pyridine, or pyrimidine; 1 Preferably, the C 5-15 azabicyclic group is selected from a benzopyrrole group, a benzothiazole group, a benzoxazole group, a benzimidazole group, a benzopyrazole group, a benzopyridine group, or a benzopyrimidine group; Preferably, L is a chemical bond or an alkyl group of C 1-4 ; Preferably, A is selected from carboxylic acid, phosphoric acid, hypophosphorous acid, phosphorous acid, sulfinic acid, sulfonic acid or boric acid groups; preferably, A is selected from -SO3H, -COOH, -PO3H2.

3. The use according to any one of claims 1-2, wherein the compound of formula I is selected from compounds of formula II as follows: Among them, X1 to X9 can be the same or different and are independently selected from C, N, O, S, and at least one of X1 to X9 is a nitrogen atom, preferably at least two or more of X1 to X9 are nitrogen atoms, and more preferably two of X1 to X9 are nitrogen atoms; m is any integer from 1 to 6, preferably any integer from 1 to 3, and more preferably any integer from 1 to 2; -L1-SO3H can be substituted on any one of the atoms X1 to X9, and each L1 can be the same or different and is independently a chemical bond or a C 1-4 alkyl group, preferably a chemical bond or a methylene group; n is any integer from 0 to 6; R1 may be substituted on any one of the atoms X1 to X9, each R1 may be the same or different, and each is independently selected from H, C 1-4 alkyl groups, preferably R1 is H, methyl or ethyl.

4. The use according to any one of claims 1-2, wherein the compound of formula I is selected from compounds of formula III as follows: Among them, -L2-A can be substituted at any position on the benzimidazole ring, and each L2 can be the same or different and is independently a chemical bond or an alkyl group of C 1-4 ; preferably, L2 is a chemical bond or a methylene group; most preferably, L2 is a chemical bond; The definitions of A, n, and m are as described in any one of claims 1-2; R2 can be substituted at any position on the benzimidazole ring. Each R2 can be the same or different and is independently selected from H, C 1-4 alkyl groups, preferably R2 is H, methyl or ethyl.

5. A metal-organic complex comprising (i) an organic ligand comprising the organic acid compound or its ionic compound according to any one of claims 1-4, and (ii) a metal component.

6. The metal-organic complex according to claim 5, wherein the metal component is a metal ion, and the metal component is preferably at least one selected from metal ions corresponding to Ce, Mn, Pd, Ag, Au, Pt, W, Co, Rh, and more preferably at least one selected from metal ions corresponding to Ce and Mn; Preferably, the molar ratio of the organic ligand to the metal element in the metal component in the metal-organic complex is 1:6 - 6:1, and more preferably 1:2 - 2:

1.

7. Application of the organic acid compound according to any one of claims 1-4 or the metal-organic complex according to any one of claims 5-6 in the preparation of a proton exchange membrane.

8. A proton exchange membrane containing the organic acid compound according to any one of claims 1-4 or the metal-organic complex according to any one of claims 5-6.

9. The proton exchange membrane according to claim 8, wherein the content of the organic acid compound in the proton exchange membrane is 0.001 - 10 wt%, preferably 0.01 - 5 wt%.

10. Application of the organic acid compound according to any one of claims 1-4 or the metal-organic complex according to any one of claims 5-6 in the preparation of a membrane electrode assembly, a fuel cell, a water electrolyzer, a hydrogen production device, a flow battery.

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