Polyphenylene ionomers for fuel cell or electrolytic cell applications

Abstract

The present invention relates to polyphenylene ionomers (PPIs) suitable for the production of membranes for use in fuel cells or electrolytic cells operating under alkaline conditions. The present invention also relates to methods for preparing such polyphenylene ionomers and methods for producing membranes thereof.

Description

Technical Field

[0001] Cross - reference to related applications This application claims priority based on U.S. Provisional Application No. 63 / 460376, filed on April 19, 2023, and European Patent Application No. 23180756.1, filed on June 21, 2023, and the entire contents of each of these applications are incorporated herein by reference for all purposes.

[0002] The present invention relates to polyphenylene ionomers (PPI) suitable for the manufacture of membranes for use in fuel cells or electrolytic cells operating under alkaline conditions. The present invention also relates to a method for preparing such polyphenylene ionomers and a method for manufacturing membranes thereof.

Background Art

[0003] Anion exchange membranes (AEMs) are important components of electrochemical devices such as fuel cells and electrolytic cells operating under alkaline conditions.

[0004] When compared with proton exchange membrane (PEM) technology operating in a strongly acidic environment, the advantage obtained by AEM - based technology is that much cheaper non - platinum group metal (PGM) electrode catalysts and electrode components can be used, thereby significantly reducing the assembly cost.

[0005] Polyphenylene exhibits excellent alkali stability and is thus an optimal candidate for AEM production.

[0006] This is particularly true when combined with alkali - stable functional groups such as dialkylpiperidinium.

[0007] In fact, the use of polymers containing phenylene repeating units for the manufacture of ion - exchange membranes, which are actually dense films, is disclosed in the art.

[0008] For example, U.S. Patent No. 7,868,124 (COMMISSARIAT A L'ENERGIE ATOMIQUE) discloses polymers comprising phenylene units, wherein at least one of the phenylene units is a phenylene side group substituted with a perfluoro group or chain having a -SO3H, -PO3H2, or -COOH group itself, and the use of these polymers for the manufacture of proton exchange membranes (PEMs) for fuel cell applications.

[0009] Furthermore, U.S. Patent No. 7,888,397 (SANDIA CORPORATION) discloses polyphenylene-based anion exchange membranes produced from casting dope solutions of (co)polymers generally obtained by Diels-Alder polymerization. The synthesis of these copolymers requires monomers that are not readily available, and they have moderate ion exchange capacity.

[0010] More recently, U.S. Patent No. 1,0290,890 (University of Delaware) discloses poly(arylpiperidinium) polymers for use as anion exchange membrane materials in fuel cell applications. These (co)polymers are generally obtained by Friedel-Crafts alkylation polymerization, which requires several reactants, such as trifluoroacetophenone, to obtain a sufficiently large molecular weight.

[0011] International Publication No. 2021150994 (Rensselaer Polytechnic Institute) discloses polyaryl(co)polymers obtained by Friedel-Crafts alkylation polymerization for use as anion exchange membrane materials in fuel cell applications. These (co)polymers also require several reactants, such as trifluoroacetophenone, to obtain sufficiently large molecular weights.

[0012] Finally, J.Power Sources, 2021, 506, 230184 discloses the synthesis of polyphenylene polymers having a piperidinium moiety by copolymerization of chloroaryl monomers: [ka]

[0013] This synthesis requires monomers that are not readily available and stoichiometric amounts of nickel catalyst. Further quaternization to piperidinium is carried out by copolymerizing the piperidine group-containing monomers and treating the resulting copolymer with iodomethane. These polyphenylene polymers are further used by solvent casting to produce anion exchange membranes for fuel cell applications. - The ionic conductivity of the film, as measured at 80°C, is moderate. [Overview of the Initiative]

[0014] Therefore, the applicant faced the challenge of providing an ionomer having an alkali-stable functional group that exhibits excellent alkali stability and is capable of carrying out anion transport.

[0015] Such ionomers need to be obtainable in high yield by polymerization of readily available or commercially available monomers, and it is necessary to achieve high molecular weight.

[0016] Such ionomers need to be soluble in several organic solvents in order to prepare doping solutions or compositions useful, for example, for film manufacturing by casting.

[0017] Such ionomers also need to be suitable for producing membranes with improved ion exchange capacity (IEC) and anionic conductivity for use in the manufacture of AEMs for fuel cells or electrolytic cells.

[0018] The applicant also faced the challenge of providing an ionomer with excellent thermal properties that can therefore be used to manufacture films capable of operating under demanding thermal conditions.

[0019] The applicant also faced the challenge of providing an ionomer that possesses excellent mechanical properties and can be used to manufacture self-supporting films based on those properties.

[0020] The applicant also faced the challenge of providing an ionomer that possesses excellent mechanical properties and, based on those properties, can be used to manufacture thin films.

[0021] The applicant also faced the challenge of providing a membrane with low water absorption.

[0022] These and further problems are all solved by the polyphenylene ionomer of the present invention, and the polyphenylene ionomer of the present invention is (i) At least one repeating unit (R) represented by the following formula pi ): [ka] (In the formula, R1 and R2 are independent of each other, C1~C 18 Represents a C4-C8 alkanediyl group selected from a list of alkyl groups, or a group that together forms a cyclic moiety. [ka] (is the opposite anion) and; (ii) At least one repeating unit selected from the group of repeating units represented by the following formula (R pp ): [ka] (wherein, R3, R4, R5, and R6 are each independently selected from the group consisting of hydrogen, alkyl, aryl, alkoxy, aryloxy, alkyl ketone, aryl ketone, fluoroalkyl, fluoroaryl, bromoalkyl, bromoaryl, chloroalkyl, chloroaryl, alkyl sulfone, aryl sulfone, alkyl amide, aryl amide, alkyl nitrile, aryl nitrile, alkyl ester, aryl ester, fluorine, chlorine, and bromine, provided that R3, R4, R5, and R6 do not simultaneously represent hydrogen) and; (iii) optionally, at least one repeating unit selected from the group of repeating units represented by the following formula (R pm ):

Chemical formula

Chemical formula

[0023] Therefore, in a second aspect, the present invention relates to a method for preparing a polyphenylene ionomer [polymer (PPI)] according to the present invention, 1. (i) At least one monomer represented by the following formula (M pi ): [ka] (In the formula, R1 and R2 are independent of each other, C1~C 18 Represents a C4-C8 alkanediyl group selected from a list of alkyl groups, or a group that together forms a cyclic moiety. Z is selected from the group consisting of Cl, Br, and I. (ii) At least one monomer represented by the following formula (M pp ): [ka] (In the formula, R3, R4, R5, and R6 are each independently selected from the list consisting of hydrogen, alkyl, aryl, alkoxy, aryloxy, alkyl ketone, aryl ketone, fluoroalkyl, fluoroaryl, bromoalkyl, bromoaryl, chloroalkyl, chloroaryl, alkyl sulfone, aryl sulfone, alkylamide, arylamide, alkyl nitrile, aryl nitrile, alkyl ester, aryl ester, fluorine, chlorine, and bromine, but R3, R4, R5, and R6 cannot simultaneously represent hydrogen.) (iii) At least one monomer (M) that can be optionally represented by the following formula pm ): [ka] (In the formula, R7, R8, R9, and R 10Each is independently selected from the list consisting of hydrogen, alkyl, aryl, alkoxy, aryloxy, alkyl ketone, aryl ketone, fluoroalkyl, fluoroaryl, bromoalkyl, bromoaryl, chloroalkyl, chloroaryl, alkyl sulfone, aryl sulfone, alkylamide, arylamide, alkyl nitrile, aryl nitrile, alkyl ester, aryl ester, fluorine, chlorine, and bromine. (iv) At least one monomer selected from the group of monomers represented by the following formula: [ka] (In the formula, R 11 and R 12 These are, independently, C1~C 18 A C5-C8 alkanediyl group selected from a list consisting of optionally fluorinated alkyl groups and optionally substituted aryl groups, or a C5-C8 alkanediyl group that together forms a cyclic moiety, or an optionally substituted biphenyldiyl group that together forms a cyclic moiety, Y is selected from the group consisting of Cl, Br, and I. A step of copolymerizing; and 2. Selectively pair anions [ka] against Anion [ka] The process of exchanging it; Regarding methods including

[0024] In a third aspect, the present invention relates to a method for preparing a polyphenylene ionomer [polymer (PPI)] according to the present invention, 1. (i) At least one monomer represented by the following formula (M pni ): [ka] (In the formula, R 13 C1~C 18 (Selected from a list of alkyl groups), (ii) At least one monomer represented by the following formula (M pp ): [ka] (In the formula, R3, R4, R5, and R6 are each independently selected from the list consisting of hydrogen, alkyl, aryl, alkoxy, aryloxy, alkyl ketone, aryl ketone, fluoroalkyl, fluoroaryl, bromoalkyl, bromoaryl, chloroalkyl, chloroaryl, alkyl sulfone, aryl sulfone, alkylamide, arylamide, alkyl nitrile, aryl nitrile, alkyl ester, aryl ester, fluorine, chlorine, and bromine, but R3, R4, R5, and R6 cannot simultaneously represent H) (iii) At least one monomer (M) that can be optionally represented by the following formula pm ): [ka] (In the formula, R7, R8, R9, and R 10 Each is independently selected from the list consisting of hydrogen, alkyl, aryl, alkoxy, aryloxy, alkyl ketone, aryl ketone, fluoroalkyl, fluoroaryl, bromoalkyl, bromoaryl, chloroalkyl, chloroaryl, alkyl sulfone, aryl sulfone, alkylamide, arylamide, alkyl nitrile, aryl nitrile, alkyl ester, aryl ester, fluorine, chlorine, and bromine. (iv) At least one monomer selected from the group of monomers represented by the following formula: [ka] (In the formula, R 11 and R 12 These are, independently, C1~C18 A C5-C8 alkanediyl group selected from a list consisting of optionally fluorinated alkyl groups and optionally substituted aryl groups, or a C5-C8 alkanediyl group that together forms a cyclic moiety, or an optionally substituted biphenyldiyl group that together forms a cyclic moiety, Y is selected from the group consisting of Cl, Br, and I. A step of copolymerizing; and 2. A step to quaternize the obtained copolymer; Regarding methods including

[0025] The present invention also relates to a liquid composition (LC) containing a polyphenylene ionomer [polymer (PPI)] and a liquid medium (L) according to the present invention.

[0026] The present invention further relates to a solid composition (SC) containing the polyphenylene ionomer [polymer (PPI)] according to the present invention.

[0027] A further object of the present invention is an article comprising a polyphenylene ionomer [polymer (PPI)], more specifically, an anion exchange membrane (AEM), an electrocatalytic layer (EL), or a membrane electrode assembly (MEA).

[0028] A further object of the present invention is a method for producing an article according to the present invention from a liquid composition (LC) or a solid composition (SC).

[0029] Finally, the present invention also relates to fuel cells or electrolytic cells containing the articles of the present invention. [Brief explanation of the drawing]

[0030] [Figure 1] This is the 1H NMR spectrum of the polyphenylene ionomer of Example 2, for which the target IEC value is 1.70. [Modes for carrying out the invention]

[0031] The polyphenylene ionomer of the present invention is (i) At least one repeating unit (R) represented by the following formula pi ): [ka] (In the formula, R1 and R2 are independent of each other, C1~C 18 Represents a C4-C8 alkanediyl group selected from a list of alkyl groups, or a group that together forms a cyclic moiety. [ka] (is the opposite anion) and; (ii) At least one repeating unit selected from the group of repeating units represented by the following formula (R pp ): [ka] (In the formula, R3, R4, R5, and R6 are each independently selected from the list consisting of hydrogen, alkyl, aryl, alkoxy, aryloxy, alkyl ketone, aryl ketone, fluoroalkyl, fluoroaryl, bromoalkyl, bromoaryl, chloroalkyl, chloroaryl, alkyl sulfone, aryl sulfone, alkylamide, arylamide, alkyl nitrile, aryl nitrile, alkyl ester, aryl ester, fluorine, chlorine, and bromine, but R3, R4, R5, and R6 cannot simultaneously represent hydrogen) and; (iii) At least one repeating unit (R) selected from the group of repeating units represented by the following formula, which can be arbitrarily chosen. pm ): [ka] (In the formula, R7, R8, R9, and R 10Each is independently selected from the list consisting of hydrogen, alkyl, aryl, alkoxy, aryloxy, alkyl ketone, aryl ketone, fluoroalkyl, fluoroaryl, bromoalkyl, bromoaryl, chloroalkyl, chloroaryl, alkyl sulfone, aryl sulfone, alkylamide, arylamide, alkyl nitrile, aryl nitrile, alkyl ester, aryl ester, fluorine, chlorine, and bromine; (iv) At least one repeating unit selected from the group of repeating units represented by the following formula: [ka] (In the formula, R 11 and R 12 These are, independently, C1~C 18 (represented by a C5-C8 alkanediyl group that is selected from a list of optionally fluorinated alkyl groups and optionally substituted aryl groups, or by a C5-C8 alkanediyl group that forms a cyclic moiety together, or by an optionally substituted biphenyldiyl group that forms a cyclic moiety together); It is a polyphenylene ionomer [polymer (PPI)] containing [a specific compound].

[0032] R1 and R2 may be methyl groups.

[0033] Advantageously, X can be selected from the group consisting of OH, Cl, Br, and I.

[0034] More advantageously, R1 and R2 are methyl groups, and X is an OH group.

[0035] Preferably, a repeating unit (R pp ) is expressed by the following formula: [ka] It is represented as follows.

[0036] Advantageously, R1 and R2 are methyl groups, and X is selected from the group consisting of OH, Cl, Br, and I, and repeating units (R pp ) is expressed by the following formula: [ka] It is represented as follows.

[0037] Optionally, the ionomer of the present invention comprises at least one repeating unit (R pm ) includes.

[0038] The ionomer of the present invention is given by the following formula: [ka] It may include at least one repeating unit (Rpm).

[0039] Repeating unit (R pm ) is expressed by the following formula: [ka] It may have.

[0040] Alternatively, the repeating unit (R pm ) is expressed by the following formula: [ka] It may have.

[0041] The ionomer of the present invention is given by the following formula: [ka] [ka] It may further include at least one repeating unit selected from the repeating units.

[0042] In some preferred embodiments, the ionomer of the present invention is of the following formula: [ka] It includes at least one repeating unit.

[0043] In some preferred embodiments, the polyphenylene ionomer according to the present invention is (i) The following formula: [ka] (In the formula, R1 and R2 are independent of each other, C1~C 18 Represents a C4-C8 alkanediyl group selected from a list of alkyl groups, or a group that together forms a cyclic moiety. [ka] (This is an anti-anion.) at least one repeating unit (Rpi) represented by; (ii) The following formula: [ka] at least one repeating unit (Rpp) represented by; It is essentially composed of or consists of these.

[0044] The polyphenylene ionomer according to the present invention is (i) The following formula: [ka] (In the formula, R1 and R2 are methyl groups, [ka] (This is a pair anion selected from the list consisting of OH, Cl, Br, and I.) at least one repeating unit (Rpi) represented by; (ii) The following formula: [ka] at least one repeating unit (Rpp) represented by; It essentially consists of, or can consist of, these.

[0045] "Essentially derived from" means that the polyphenylene ionomer according to the present invention contains repeating units different from the repeating units of (i) and (ii) above in an amount of less than 5 mol%, preferably less than 2 mol%, and more preferably less than 1 mol%, based on the total number of moles of all repeating units.

[0046] Typically, the polyphenylene ionomer (PPI) according to the present invention contains at least about 30 mol%, preferably at least 40 mol%, and more preferably at least 50 mol%, of the repeating units (R) represented by the following formula, based on the total number of moles of all repeating units. pi ) including: [ka] (In the formula, R1 and R2 are independent of each other, C1~C 18 Represents a C4-C8 alkanediyl group selected from a list of alkyl groups, or a group that together forms a cyclic moiety. [ka] (This is an anti-anion).

[0047] By knowing the molar composition of the polyphenylene ionomer (PPI) according to the present invention, it is possible to calculate the ion exchange capacity (IEC), which is expressed as millimoles of ionic species per gram of ionomer.

[0048] The ion exchange capacity represents the relative amount of cationic groups bonded to the ionomer, and these cationic groups are responsible for transporting negatively charged ions through the membrane produced from the ionomer.

[0049] IEC can be measured, for example, by titration using techniques well known to those skilled in the art.

[0050] Another object of the present invention is a method for preparing a polyphenylene ionomer [polymer (PPI)] according to any of the claims, 1. (i) At least one monomer represented by the following formula (M pi ): [ka] (In the formula, R1 and R2 are independent of each other, C1~C 18 Represents a C4-C8 alkanediyl group selected from a list of alkyl groups, or a group that together forms a cyclic moiety. Z is selected from the group consisting of Cl, Br, and I. (ii) At least one monomer represented by the following formula (M pp ): [ka] (In the formula, R3, R4, R5, and R6 are each independently selected from the list consisting of hydrogen, alkyl, aryl, alkoxy, aryloxy, alkyl ketone, aryl ketone, fluoroalkyl, fluoroaryl, bromoalkyl, bromoaryl, chloroalkyl, chloroaryl, alkyl sulfone, aryl sulfone, alkylamide, arylamide, alkyl nitrile, aryl nitrile, alkyl ester, aryl ester, fluorine, chlorine, and bromine, but R3, R4, R5, and R6 cannot simultaneously represent hydrogen.) (iii) At least one monomer (M) that can be optionally represented by the following formula pm ): [ka] (In the formula, R7, R8, R9, and R 10Each is independently selected from the list consisting of hydrogen, alkyl, aryl, alkoxy, aryloxy, alkyl ketone, aryl ketone, fluoroalkyl, fluoroaryl, bromoalkyl, bromoaryl, chloroalkyl, chloroaryl, alkyl sulfone, aryl sulfone, alkylamide, arylamide, alkyl nitrile, aryl nitrile, alkyl ester, aryl ester, fluorine, chlorine, and bromine. (iv) At least one monomer selected from the group of monomers represented by the following formula: [ka] (In the formula, R 11 and R 12 These are, independently, C1~C 18 A C5-C8 alkanediyl group selected from a list consisting of optionally fluorinated alkyl groups and optionally substituted aryl groups, or a C5-C8 alkanediyl group that together forms a cyclic moiety, or an optionally substituted biphenyldiyl group that together forms a cyclic moiety, Y is selected from the group consisting of Cl, Br, and I. A step of copolymerizing; and 2. Selectively pair anions [ka] against Anion [ka] The process of exchanging it; Regarding methods including

[0051] Monomer (M pi ) can be prepared, for example, by the method described in Journal of Power Sources, 2021, 506, 230184, which is Friedel-Crafts alkylation: [ka]

[0052] Comonomers are commercially available or can be synthesized by those skilled in the art.

[0053] In step 1, copolymerization is typically carried out using a phenylene monomer having a Y group selected from the group consisting of Cl, Br, and I. Good results were obtained when Y was Cl.

[0054] Copolymerization is typically carried out in an inert atmosphere in the presence of a liquid medium. The phenylene monomer and the resulting polyphenylene ionomer are usually soluble in the liquid medium.

[0055] Liquid media are usually anhydrous.

[0056] For example, the liquid medium can be selected from polar aprotic solvents, preferably from the group consisting of N-methylpyrrolidone (NMP), dimethylacetamide (DMAc), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), methyl-5-dimethylamino-2-methyl-5-oxopentanoate (commercially available under the trade name Rhodialsov Polarclean®), triethyl phosphate (TEP), and mixtures thereof.

[0057] To ensure a reductive coupling reaction between phenylene monomers, catalyst systems well known to those skilled in the art are typically used.

[0058] For example, nickel-catalyzed coupling reactions are described in several U.S. patents, including U.S. Patent No. 5,227,457; U.S. Patent No. 5,886,130; and U.S. Patent No. 5,824,744, the disclosures of which are fully incorporated herein by reference.

[0059] Typically, this method involves coupling dihaloaryl species using a nickel catalyst in a polar aprotic solvent such as N,N-dimethylacetamide (DMAc) or N-methylpyrrolidone (NMP), in combination with a triphenylphosphine (TPP) ligand and a zinc metal reducing agent. Such a reaction can be expressed as follows, where Y is a substituent and X is a halogen: [ka]

[0060] The above method allows for the production of substituted polyphenylenes on a commercial scale.

[0061] The reaction mixture is typically filtered through, for example, a Celite plug, and then solidified in a non-solvent (such as methanol) of the polyphenylene ionomer. The polyphenylene ionomer can be further recovered by filtration.

[0062] The resulting copolymer can be treated with methanol containing 5% HCl, filtered, and thoroughly washed with methanol to remove excess zinc powder.

[0063] In step 2, the anti-anion process [ka] against Anion [ka] The exchange is usually carried out by any technique well known to those skilled in the art. For example, [ka] Polyphenylene ionomers having the properties of polyphenylene ionomers can be obtained by immersing them in a saturated NaCl solution for several hours, typically 2 hours. [ka] The excess NaCl can be removed by ion exchange and then washing with fresh deionized water for several hours, typically 2 hours.

[0064] A further object of the present invention is a method for preparing a polyphenylene ionomer [polymer (PPI)] according to the present invention, 1'. (i) At least one monomer represented by the following formula (M pni ): [ka] (In the formula, R 13 C1~C 18 (Selected from a list of alkyl groups), (ii) At least one monomer represented by the following formula (M pp ): [ka] (In the formula, R3, R4, R5, and R6 are each independently selected from the list consisting of hydrogen, alkyl, aryl, alkoxy, aryloxy, alkyl ketone, aryl ketone, fluoroalkyl, fluoroaryl, bromoalkyl, bromoaryl, chloroalkyl, chloroaryl, alkyl sulfone, aryl sulfone, alkylamide, arylamide, alkyl nitrile, aryl nitrile, alkyl ester, aryl ester, fluorine, chlorine, and bromine, but R3, R4, R5, and R6 cannot simultaneously represent H) (iii) At least one monomer (M) that can be optionally represented by the following formula pm ): [ka] (In the formula, R7, R8, R9, and R 10Each is independently selected from the list consisting of hydrogen, alkyl, aryl, alkoxy, aryloxy, alkyl ketone, aryl ketone, fluoroalkyl, fluoroaryl, bromoalkyl, bromoaryl, chloroalkyl, chloroaryl, alkyl sulfone, aryl sulfone, alkylamide, arylamide, alkyl nitrile, aryl nitrile, alkyl ester, aryl ester, fluorine, chlorine, and bromine. (iv) At least one monomer selected from the group of monomers represented by the following formula: [ka] (In the formula, R 11 and R 12 These are, independently, C1~C 18 A C5-C8 alkanediyl group selected from a list consisting of optionally fluorinated alkyl groups and optionally substituted aryl groups, or a C5-C8 alkanediyl group that together forms a cyclic moiety, or an optionally substituted biphenyldiyl group that together forms a cyclic moiety, Y is selected from the group consisting of Cl, Br, and I. A step of copolymerizing; and 2'. Steps to quaternize the obtained copolymer; Regarding methods including

[0065] Step 1' is typically performed under the same conditions as those described above for Step 1.

[0066] The excess zinc powder can be removed by treating the resulting copolymer with methanol containing 5% HCl, filtering it, and thoroughly washing it with methanol. Therefore, the amine groups in the resulting copolymer are considered to be in the form of hydrochloride salts.

[0067] Neutralization of the hydrochloride salt form can be carried out by treating the copolymer in the NMP solution with a base, such as an aqueous NaOH solution, to recover the amine group, as shown in the following scheme: [ka]

[0068] In step 2', the quaternization of the amine group of the copolymer obtained in step 1' can be carried out, for example, by treating the copolymer with an alkyl halide, usually in solution. For example, the copolymer in NMP solution can be treated with an excess amount of methyl iodide for quaternization at room temperature, e.g., 30°C, as shown in the following scheme: [ka]

[0069] Another object of the present invention relates to a liquid composition (LC) comprising a polyphenylene ionomer [polymer (PPI)] and a liquid medium (L) according to the present invention.

[0070] The medium (L) preferably contains at least one organic solvent. Suitable examples of organic solvents are: - Petroleum fractions consisting of aliphatic hydrocarbons, more specifically paraffins, such as pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, or cyclohexane, as well as naphthalenes and aromatic hydrocarbons, more specifically aromatic hydrocarbons, such as mixtures of benzene, toluene, xylene, cumene, and alkylbenzenes; - Aliphatic or aromatic halogenated hydrocarbons, more specifically perchloroethylenes, such as tetrachloroethylene and hexachloroethane; - Partially chlorinated hydrocarbons, such as dichloromethane, chloroform, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, pentachloroethane, trichloroethylene, 1-chlorobutane, 1,2-dichlorobutane, monochlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1,2,4-trichlorobenzene, or mixtures of different chlorobenzenes; - Aliphatic, alicyclic, or aromatic ether oxides, more specifically diethyl oxide, dipropyl oxide, diisopropyl oxide, dibutyl oxide, methyl terbutyl ether, dipentyl oxide, diisopentyl oxide, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, benzyl oxide; dioxane, tetrahydrofuran (THF); - Dimethyl sulfoxide (DMSO); - Glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol mono-n-butyl ether; - Glycol ether esters such as ethylene glycol methyl ether acetate, ethylene glycol monoethyl ether acetate, and ethylene glycol monobutyl ether acetate; - Alcohols containing polyhydric alcohols, such as methyl alcohol, ethyl alcohol, diacetone alcohol, ethylene glycol, etc. - Ketones, such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, isophorone, etc. - Linear or cyclic esters, such as isopropyl acetate, n-butyl acetate, methyl acetate, dimethyl phthalate, γ-butyrolactone, etc. - Linear or cyclic carboxamides, such as N,N-dimethylacetamide (DMAc), N,N-diethylacetamide, dimethylformamide (DMF), diethylformamide, or N-methyl-2-pyrrolidone (NMP); - For example, organic carbonates such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, ethylmethyl carbonate, ethylene carbonate, and vinylene carbonate; - Phosphate esters, such as trimethyl phosphate and triethyl phosphate (TEP); - Urea, such as tetramethylurea, tetraethylurea, etc. - Methyl-5-dimethylamino-2-methyl-5-oxopentanoate (commercially available under the trade name Rhodialsov Polarclean®) That is the case.

[0071] Preferably, the at least one organic solvent is selected from polar aprotic solvents, and more preferably from the group consisting of N-methylpyrrolidone (NMP), dimethylacetamide (DMAc), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), methyl-5-dimethylamino-2-methyl-5-oxopentanoate (commercially available under the trade name Rhodialsov Polarclean®), and triethyl phosphate (TEP).

[0072] Good results were obtained when dimethyl sulfoxide (DMSO) was used as the organic solvent.

[0073] The liquid composition (LC) typically contains at least 3% by weight, preferably at least 5% by weight, and more preferably at least 10% by weight of polyphenylene ionomer [polymer (PPI)] based on the total weight of the liquid composition (LC).

[0074] Furthermore, the liquid composition (LC) typically contains up to 40% by weight, preferably up to 30% by weight, and more preferably up to 20% by weight, of polyphenylene ionomer [polymer (PPI)] based on the total weight of the liquid composition (LC).

[0075] The liquid composition (LC) may optionally contain additional components such as stabilizers and radical scavengers.

[0076] A further object of the present invention relates to a solid composition (SC) containing a polyphenylene ionomer [polymer (PPI)] according to the present invention.

[0077] The solid composition (SC) may consist of polyphenylene ionomer (PPI), or it may optionally contain additional components such as stabilizers, radical scavengers, plasticizers, or processing aids.

[0078] The solid composition (SC) typically contains at least 90% by weight, preferably at least 95% by weight, and more preferably at least 99% by weight of polyphenylene ionomer [polymer (PPI)] based on the total weight of the solid composition (SC).

[0079] The present invention also relates to articles containing the polyphenylene ionomer [polymer (PPI)] according to the present invention.

[0080] Preferably, the article according to the present invention is an anion exchange membrane (AEM), an electrocatalytic layer (EL), or a membrane electrode assembly (MEA).

[0081] In the first embodiment, the article is an anion exchange membrane (AEM) for fuel cell or electrolytic cell applications, and is also referred to herein as the “membrane”.

[0082] The film can be obtained from the liquid composition (LC) according to the present invention using techniques known in the art, such as impregnation, casting, and coating (e.g., roller coating, gravure coating, reverse roll coating, dip coating, spray coating).

[0083] Therefore, another object of the present invention is a method for manufacturing an article according to the present invention, comprising impregnating, casting, or coating with a liquid composition (LC).

[0084] The solid composition (SC) can, advantageously, be converted into a film by conventional extrusion technology.

[0085] Therefore, another object of the present invention is a method for manufacturing an article according to the present invention, comprising extruding a solid composition (SC).

[0086] The membrane may optionally be reinforced, for example, by laminating a membrane extruded from a solid composition (SC) onto a suitable reinforcing support, or by impregnating a porous support with a liquid composition (LC). Suitable supports can be made from a wide variety of components. Porous supports can be made from woven or nonwoven polyolefin membranes, such as hydrocarbon polymers like polyethylene or polypropylene, or polyesters, such as poly(ethylene terephthalate). Fluorinated polymer porous supports are generally preferred for use in fuel cell applications because they are highly chemically inert. Biaxially oriented PTFE porous supports (also known as ePTFE membranes) are particularly preferred supports. Such supports are commercially available, in particular, under the trademark names GORE-TEX® and TETRATEX®.

[0087] Polyphenylene ionomers (PPIs) in the membrane [ka] If it is in this form, the excess NaCl can be removed by immersing the membrane in a saturated NaCl solution for several hours, typically 2 hours, and then washing it with fresh deionized water for several hours, typically 2 hours. [ka] It can be changed to a different form.

[0088] Similarly, polyphenylene ionomers (PPIs) in the membrane [ka] Form or [ka] If it is in this form, this can be removed by immersing the film in a saturated NaOH solution for several hours. [ka] It can be changed to a different form.

[0089] In a second embodiment, the article of the present invention is an electrocatalytic layer (EL).

[0090] The electrocatalytic layer can be advantageously prepared starting from a liquid composition (LC) according to the present invention, further comprising catalyst particles. The liquid composition is generally referred to as “catalytic ink.” Typical catalyst particles include metals such as iron, manganese, cobalt, nickel, platinum, ruthenium, gold, palladium, rhodium, iridium, and osmium; and active compounds selected from their conductive oxides and alloys. The active compounds are generally supported on a suitable material, preferably a conductive material, which is generally referred to herein as “support.” The support is advantageously selected from carbon powder, for example, carbon black.

[0091] The amount of catalyst particles (including the support, if any) in the catalyst ink is generally at least 1% by weight of the total weight of the catalyst ink. Preferably, the amount is at least 3% by weight, more preferably at least 5% by weight. Advantageously, the amount of catalyst particles (including the support, if any) in the catalyst ink is at most 50% by weight, preferably at most 40% by weight, and more preferably at most 30% by weight, based on the total weight of the catalyst ink.

[0092] The electrocatalytic layer (EL) can be manufactured, for example, by screen printing or solution coating a catalyst ink onto the surface of an anion exchange film (AEM).

[0093] In a third embodiment, the article is a membrane electrode assembly (MEA). The membrane electrode assembly comprises a membrane having first and second surfaces, a first electrocatalytic layer (EL) bonded to the first surface, and a second electrocatalytic layer (EL) bonded to the second surface, wherein the membrane, the first or second electrocatalytic layer, or at least one of them comprises a polyphenylene ionomer as defined above.

[0094] The present invention ultimately relates to a fuel cell or electrolytic cell containing the article of the present invention.

[0095] All definitions and priorities set forth above with respect to polyphenylene ionomers (PPIs) or methods for producing the same also apply to compositions (LC) and (SC), and to any articles containing said polyphenylene ionomers (PPIs).

[0096] The present invention is illustrated in more detail hereafter herein by the examples contained in the following experimental section; however, the examples are illustrative only and should not be construed as limiting the scope of the invention. [Examples]

[0097] raw materials 2,5-Dichlorobenzophenone was supplied by Byelen Chemicals. Bis(triphenylphosphine)nickel dichloride was obtained from Alfa Aesar. Zinc powder was supplied by Umicore. Methyl iodide, methanol (MeOH), and trifluoromethanesulfonic acid (trifluic acid) were supplied by ThermoFisher Scientific. Chlorobenzene, N-methyl-4-piperidone, 1,3-dichlorobenzene, triphenylphosphine, potassium iodide, dichloromethane (DCM), anhydrous N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), and dimethylacetamide (DMAC) were obtained from Sigma Aldrich. 4,4-Bis(4-chlorophenyl)-1-methylpiperidine and 4,4-Bis(4-chlorophenyl)-1,1-dimethylpiperidine-1-ium iodide were prepared as described below.

[0098] Monomer synthesis The monomer synthesis was carried out by modifying the method described in Journal of Power Sources, 2021, 506, 230184, as shown in the following reaction scheme: [ka]

[0099] In a round-bottom flask equipped with mechanical stirring, 0.22 mol (25.0 g) of 1-methyl-4-piperidone was added with 166.25 mL (0.662 mol) of chlorobenzene under a nitrogen atmosphere, and 477 mL of trifluoromethanesulfonic acid was added to this solution. The mixture was stirred in a water / ice bath at 0°C for 6 hours, and then stirred at 30°C for 12 hours. The resulting solution was made basic by adding 2 M aqueous NaOH and extracted with dichloromethane. The organic phase was washed with deionized water and saturated brine, and then dried over anhydrous Na₂SO₄. After removing the solvent under reduced pressure, the crude product was purified by silica gel column chromatography using MeOH / DCM (v / v, 1 / 10) as the eluent to obtain 4,4-bis(4-chlorophenyl)-1-methylpiperidine as a viscous oil in 81% yield (57.25 g, 0.179 mol).

[0100] In a brown-coated round-bottom flask equipped with mechanical stirring, 0.08 mol (25.62 g) of 4,4-bis(4-chlorophenyl)-1-methylpiperidine, 50 mL of dichloromethane, and 15 mL (0.24 mol) of methyl iodide were added under a nitrogen atmosphere. For quaternization, the solution was stirred at room temperature for 12 hours. 4,4-bis(4-chlorophenyl)-1,1-dimethylpiperidine-1-ium iodide was recovered by removing excess methyl iodide and dichloromethane under reduced pressure. Finally, a white crystalline solid was obtained by recrystallization from anhydrous ethanol.

[0101] Synthesis of copolymers Example 1: Copolymerization of 1,3-dichlorobenzene and 2,5-dichlorobenzophenone [ka] This process was carried out with modifications to the one described in U.S. Patent No. 5,886,130. All materials were placed in a reaction vessel in a dry glove box under an inert atmosphere (nitrogen). In a 100 mL jacketed three-neck round-bottom flask equipped with a mechanical stirring shaft, bis(triphenylphosphine)nickel chloride (0.810 g, 1.239 mmol), potassium iodide, triphenylphosphine, 2,5-dichlorobenzophenone (7.777 g, 30.97 mmol), 1,3-dichlorobenzene (4.552 g, 30.97 mmol), activated zinc powder, and anhydrous N-methylpyrrolidone (52 mL) were added. After sealing with a rubber septum in the glove box, the flask was removed and connected to a circulating heater / chiller and then to a low-flow nitrogen purge. The mixture was heated to 70°C over 1 hour and stirred overnight. The following day, the mixture was passed through a Celite plug and pressure filtered, then coagulated in 500 mL of methanol and filtered. The resulting polymer was treated with methanol containing 5% HCl, filtered, and thoroughly washed with methanol.

[0102] Examples 2-5: Copolymerization of 4,4-bis(4-chlorophenyl)-1,1-dimethylpiperidine-1-ium iodide and 2,5-dichlorobenzophenone [ka] Example 2 The preparation was carried out according to the procedure of Synthesis Example 1, using 9.799 g of 2,5-dichlorobenzophenone (39.02 mmol), 10.593 g of 4,4-bis(4-chlorophenyl)-1,1-dimethylpiperidine-1-ium iodide (22.92 mmol), and 110 mL of anhydrous N-methylpyrrolidone. The target IEC was 1.70. 1 The IEC value calculated using 1H NMR was 1.73 (see Table 1).

[0103] Example 3 The preparation was carried out according to the procedure of Synthesis Example 1, using 9.176 g of 2,5-dichlorobenzophenone (36.54 mmol), 11.736 g of 4,4-bis(4-chlorophenyl)-1,1-dimethylpiperidine-1-ium iodide (25.39 mmol), and 114 mL of anhydrous N-methylpyrrolidone. The target IEC was 1.85. 1 The IEC value calculated using 1H NMR was 1.85 (see Table 1).

[0104] Example 4 The preparation was carried out according to the procedure of Synthesis Example 1, using 8.555 g of 2,5-dichlorobenzophenone (34.07 mmol), 12.883 g of 4,4-bis(4-chlorophenyl)-1,1-dimethylpiperidine-1-ium iodide (27.87 mmol), and 118 mL of anhydrous N-methylpyrrolidone. The target IEC was 2.00. 1 The IEC calculated using 1H NMR was 1.99 (see Table 1).

[0105] Example 5 The preparation was carried out according to the procedure of Synthesis Example 1, using 6.999 g of 2,5-dichlorobenzophenone (27.87 mmol), 15.745 g of 4,4-bis(4-chlorophenyl)-1,1-dimethylpiperidine-1-ium iodide (34.07 mmol), and 118 mL of anhydrous N-methylpyrrolidone. The target IEC was 2.33. 1 The IEC value calculated using 1H NMR was 2.33 (see Table 1).

[0106] Determination of molecular weight Measurements were performed at 45°C using two Agilent PLgel 5μm, MiniMix-D (250×4.6mm) columns linked to one Agilent PLgel 5μm, MiniMix-D guard (50×4.6mm) column. UV detection was set to 270nm. The mobile phase consisted of dimethylacetamide (DMAc) at a flow rate of 0.3 mL / min. 5 μL of sample was injected, and calibration was performed using a polystyrene standard. Mw represents the weight-average molar mass, expressed in g / mol units.

[0107] Calculation of theoretical ion exchange capacity (IEC) Regarding the theoretical IEC of each copolymer, in DMSO 1 The calculations were performed using 1H NMR. The four types of protons represented by the following scheme are: 1 It can be identified using 1H NMR: [ka]

[0108] By comparing the number of known aromatic protons in each repeating unit (8 protons) with the number of observed aliphatic protons for signal 4, the composition (mol percent) of the repeating unit can be calculated using the following formula. Here, when m=0 and n=1, the expected number of protons for signal 4 is 6, and the observed number of protons is 1 It is considered that this is given by the integral of the signals assigned to 4 protons on the 1H NMR spectrum:

number

[0109] Therefore, the copolymer reported in Figure 1 1 In the 1H NMR spectrum (target IEC=1.70):

number

[0110] From the molar ratio of the repeating units, the average molecular weight of the repeating units (based on the OH- form) can be calculated, which in the example above, where m=0.622 and n=0.378, is 218.55 g / mol. Using this information, a person skilled in the art can calculate the ion exchange capacity as shown below:

number

[0111] Membrane casting Each polymer was dissolved in DMSO at 100–120°C (10–12% by weight) to create a film. The pale yellow doping solution was filtered and poured onto a heated glass plate, and cast into a thin film using a doctor blade. The glass plate was immediately transferred to a preheated oven at 70°C under a nitrogen atmosphere and left for 4 hours without vacuum until tack-free. After 4 hours, the temperature was increased to 120°C and the film was annealed under vacuum for 16–18 hours. Following the annealing process, the film was peeled from the glass plate by immersion in deionized water at room temperature.

[0112] Membrane ion exchange Before measuring chloride conductivity, the membrane was ion-exchanged in a saturated NaCl solution for 2 hours, then washed twice with fresh deionized water for 2 hours each to remove excess NaCl. - The form was recovered.

[0113] Ionic conductivity (Cl - Measurement of morphology The in-plane ionic conductivity (σ, mS / cm) of each film (6 mm × 30 mm) was measured using a BekkTech four-terminal probe platinum electrode (BT-512) conductivity test system equipped with an ivium potentiostat. Measurements were collected in a fully hydrated state. The test cell containing the fixed film was immersed in deionized ultrapure water at 80°C and allowed to equilibrate for 15 minutes before measurement. Ionic conductivity was calculated according to the following formula:

number

[0114] result Table 1 reports some of the characteristics of the fabricated film.

[0115] [Table 1]

[0116] As can be seen from Table 1, the polyphenylene ionomers from Examples 2-5 have high molecular weights. Furthermore, these high molecular weights can be combined with high IEC.

[0117] The excellent correlation between the target value and the calculated value indicates that the IEC can be easily adjusted by setting the comonomer ratio during the copolymerization process. A high value of 2.33 mmol / g can be achieved while maintaining a large molecular weight.

[0118] The films obtained using the polyphenylene ionomers according to Examples 2-5 are self-supporting films.

[0119] From Table 1, the films produced by Examples 2-5 are Cl - In terms of morphology, commercially available self-supporting membranes (e.g., similarly Cl - It can be seen that it exhibits higher ionic conductivity at 80°C than other materials such as Fumasep(registered trademark) FAA-3-50 and PiperION.

[0120] Surprisingly, the films according to Examples 3-4 exhibit higher ionic conductivity at 80°C despite having lower IEC values ​​than commercially available self-supporting films.

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