Conjugated acid proton exchange polymers and methods of making and using conjugated acid proton exchange polymers

Abstract

A conjugated acid proton exchange polymer molecule comprising an acidic aromatic unit in a main chain or a side chain wherein the acidic aromatic unit is a conjugated acid of an alkaline aromatic unit; and a non-coordinating counter anion ionically bonded to the acidic aromatic unit.

Description

Related applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 457,873, filed April 7, 2023, the entire contents of which are incorporated herein by reference. Background Technology

[0002] In electrochemical cells such as hydrogen fuel cells and water electrolysis systems, proton exchange membranes (PEMs) are used to selectively transport protons. A proton exchange membrane (PEM) is a semi-permeable membrane that can transport protons (… However, it does not allow gas to permeate. PEMs are typically composed of a porous framework with highly acidic functional groups. For example, perfluorosulfonic acid-based PEMs, such as Nafion™ (The Chemours Company, Wilmington, Delaware, USA) and Aquivion® (Solvay SA Corporation, Brussels, Belgium), contain a porous polytetrafluoroethylene (PTFE) framework with sulfonic acid side groups. The easily dissociable sulfonic acid groups act as proton transporters in the membrane. In hydrogen fuel cells, hydrogen (… ) decomposes into protons at the anode ( ) and electrons; protons pass through the PEM and react with oxygen at the cathode ( Electrons combine to form water, while electrons flow through an external circuit to generate electrical energy. In a water electrolysis system, electrical energy causes water at the anode to decompose into oxygen (…). ) and proton ( Protons pass through the PEM and combine with electrons at the cathode to produce hydrogen gas. ).

[0003] A membrane electrode assembly (MEA) may include a proton exchange membrane situated between a first catalyst layer and a second catalyst layer. The catalyst layers are conductive electrodes (anode and cathode) in which an electrochemical catalyst, such as a metal, metal alloy, or metal oxide, is embedded. The catalyst may be bonded to a solid catalyst support, typically a conductive carbon material with a high specific surface area (such as graphite or graphene). The electrochemical catalyst reduces the activation energy required for electrochemical reactions to occur at the electrodes, such as the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in water electrolysis applications, and the hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR) in fuel cell applications.

[0004] In some applications, the catalyst layer comprises a supported catalyst mixed with an ionomer (an ionically conductive polymer). The ionomer can bind the catalyst within the electrode, bind the catalyst layer to the proton exchange membrane, and provide transport channels for cations (such as protons), thereby improving cation conductivity. In some MEAs, the catalyst layer is formed separately from the PEM and then layered onto the PEM within the MEA stack. In other MEAs, the catalyst layer is coated onto the PEM to form a catalyst-coated membrane (CCM).

[0005] Water electrolysis and fuel cell applications involve strong oxidative and reduction chemical processes under conditions ranging from ambient to high temperatures and acidic environments. Therefore, PEMs, ionomers, and the molecular functional groups responsible for proton transport within them must remain stable under harsh redox stress conditions. However, most conventional polymers used in PEMs, as well as conventional polymers used as ionomers (such as Nafion™ and Aquivion®), contain sulfonic acid functional groups as proton transporters. The ability of sulfonic acid functional groups to withstand redox stress generated by electrochemical operation is limited, primarily due to the inherent physicochemical properties of sulfur. Furthermore, sulfonic acid groups participate in secondary redox reactions, leading to poisoning of platinum group metal catalysts and depolymerization of the polymer matrix. Attached Figure Description

[0006] The accompanying drawings illustrate various embodiments and are part of the specification. The illustrated embodiments are exemplary only and do not limit the scope of this disclosure. Throughout the drawings, the same or similar reference numerals denote the same or similar elements.

[0007] Figure 1 This demonstrates the preparation of proton-conductive polybenzimidazolium (BN) that is ionically bonded to tetrafluoroborate counterion anions. Exemplary reaction schemes for polymers.

[0008] Figure 2 This demonstrates the preparation of ionic bonds with noncoordinate tetrafluoroborate counter anions. Another exemplary reaction scheme for polymers.

[0009] Figure 3 This demonstrates the preparation of ionic bonds with any of a variety of different noncoordinate metal fluoride counter anions. Exemplary reaction schemes for polymers.

[0010] Figure 4 This demonstrates the preparation of ionic bonds with noncoordinate tetrafluoroborate counter anions. Another exemplary reaction scheme for polymers.

[0011] Figure 5An example proton exchange membrane water electrolysis system comprising conjugated acid proton exchange polymers (PEM) and / or ionomers is shown.

[0012] Figure 6 An example proton exchange membrane fuel cell comprising a conjugated acid proton exchange polymer (PEM) and / or an ionomer is shown. Detailed Implementation

[0013] This article describes conjugated acid proton exchange polymers and methods for preparing and using them by post-polymerization functional group modification of basic aromatic polymers. Basic aromatic polymers contain basic aromatic units (such as aryl and / or heteroaryl) in their main chain and / or side chains or side groups. Examples of basic aromatic polymers include, but are not limited to, polybenzimidazole (PBI) polymers and polyaniline (PANI) polymers. The basic aromatic units are weakly basic and react with strong acids in acid-base reactions to form acidic aromatic units ionically bonded to counterions. The acidic aromatic unit is the conjugated acid of the basic aromatic unit. In some embodiments, the counter anion is the conjugated base of a strong acid, but the ion exchange groups can be adjusted according to the application and desired performance. The acidic aromatic unit readily dissociates in an aqueous environment to form a structure containing hydrated protons (…). The equilibrium mixture of ) . Therefore, the easily dissociable acidic aromatic units can act as proton transporters.

[0014] The conjugated acid proton exchange polymers described herein can be used in electrochemical cell applications, such as in PEMs, ionomers, catalyst layers, and membrane electrode assemblies (MEAs), as well as other applications. Counter anions (conjugated bases) are non-coordinated anions that remain stable and inert under harsh electrochemical reaction conditions. They do not cause electrochemical catalyst poisoning through reaction with metal catalysts, nor do they participate in secondary depolymerization reactions. Therefore, ionomers and PEMs based on the conjugated acid proton exchange polymers described herein can reduce or eliminate catalyst poisoning compared to conventional ionomers and polymers, including sulfonate-functionalized polymers such as Nafion®.

[0015] Various definitions are provided to aid in understanding the various aspects of this disclosure. As used herein, each term or expression (e.g., alkyl, m, n, etc.) is defined independently of its definition elsewhere in this disclosure when used multiple times. In the event of any conflict with any patent application or patent incorporated herein by reference, this specification (including the definitions) shall prevail.

[0016] As used herein, “polymer” means a substance comprising polymer molecules of the same or different polymer species, including mixtures of polymer molecules of the same polymer species, wherein the polymer molecules in the mixture may differ from other polymer molecules in the same sample in terms of chain length and / or specific structural arrangement (e.g., irregularity of monomer unit orientation, position and / or length of end groups and / or any side chains or side groups). “Polymer” includes homopolymers, copolymers, terpolymers, interpolymers, etc.

[0017] As used in this article, "polymer molecule" or "macromolecule" refers to a molecule with a relatively high molecular weight whose structure contains (actually or theoretically) a number of repeating units (e.g., about 100 or more monomer units) derived from molecules with a relatively low molecular weight (such as monomer molecules).

[0018] As used in this article, "polymerization" refers to the process of converting one or more monomers into a polymer.

[0019] As used in this article, “oligomer” refers to a substance that contains oligomer molecules.

[0020] As used herein, “oligomery” refers to a molecule with a medium relative molecular mass whose structure contains (actually or theoretically) fewer repeating units (e.g., about 5 to about 100 monomer units) derived from molecules with a lower relative molecular mass (such as monomer molecules).

[0021] As used in this article, “oligomery” refers to the process of converting one or more monomers into oligomers.

[0022] The principles, concepts, and characteristics described herein with reference to polymers, polymer molecules, and polymerization are equally applicable to oligomers, oligomer molecules, and oligomers, respectively. Therefore, without departing from the scope of this disclosure, any and all uses of the terms polymers, polymer molecules, and polymerizations herein are to be replaced by the terms oligomers, oligomer molecules, and oligomers, respectively.

[0023] As used in this article, "ionomer" refers to a polymer that contains ionomer molecules.

[0024] As used herein, "ionomer molecule" refers to a polymer molecule in which a small but significant proportion of structural units have ionizable side groups or ionic side groups (including the ion exchange groups described herein), or both. Typically, no more than about 15 molar percentage of structural units have ionizable side groups or ionic side groups.

[0025] As used in this article, "monomer" refers to a substance that contains monomer molecules.

[0026] As used in this article, "monomer molecule" refers to a molecule that can be polymerized or oligomerized to form polymer molecules or oligomer molecules. Monomer molecules provide the structural units for the basic structure of polymer molecules or oligomer molecules.

[0027] As used in this article, "copolymer" refers to a polymer derived from one or more monomer species.

[0028] As used herein, “structural unit” refers to an atom or group of atoms (including, if any, side-mounted atoms or groups) that constitute part of the structure of a polymer molecule (or oligomer molecule, block or chain).

[0029] As used in this article, “repeating unit” refers to the structural unit that repeatedly constitutes a polymer molecule (or oligomer molecule, block or chain).

[0030] As used in this article, "monomer unit" refers to the largest structural unit provided by a single monomer molecule for the structure of a polymer molecule or oligomer molecule.

[0031] As used herein, a “block” refers to a portion of a polymer molecule (or oligomer molecule) that contains multiple structural units and has at least one feature that is not present in adjacent portions.

[0032] As used herein, "chain" refers to the whole or part of a polymer molecule (or oligomer molecule or block) that contains a sequence of linear or branched structural units between two boundary structural units, each of which may be an end group, a branching point, or other specified characteristic structure of the polymer molecule.

[0033] As used in this article, "main chain" refers to the chain of a polymer molecule, and all other chains (long chains or short chains, or both) can be considered as descending from that chain (e.g., side chains).

[0034] As used in this article, "side chain" refers to an oligomeric (short chain) or polymeric (long chain) branch that extends from the main chain of a polymer molecule.

[0035] As used in this article, "side group" or "dangling group" refers to a branch that extends from the chain (such as the main chain) and is neither oligomerized nor polymerized.

[0036] The principles, concepts, and features described herein with reference to sidechains are equally applicable to sidebases. Therefore, without departing from the scope of this disclosure, any and all uses of the term "sidechain" herein may be replaced with the term "sidebase".

[0037] As used herein, "crosslinking" refers to a small region in a polymer molecule from which at least four chains extend. Crosslinking is typically formed through reactions involving sites or groups on existing polymer molecules, or through interactions between existing polymer molecules.

[0038] The term "crosslinked" refers to the state in which originally separate polymer molecules are connected to each other at points other than their ends.

[0039] As used herein, "catalyst particle" refers to particles that are "black" or in pure form (e.g., without any catalyst support to which the catalyst particle may be attached, and without any catalyst additives), which can increase the reaction rate but do not change the overall standard Gibbs free energy change of the reaction. Catalyst particles can be single molecules (including but not limited to monomer molecules), groups of molecules, crystal structures (such as crystal structures in metal oxides), polymer molecules, or oligomer molecules. Catalyst particles can have any suitable size and shape, such as micron particles, nanoparticles, or nanotubes. Catalyst particles can include, for example, metals, metal alloys, metal oxides, metal halides (such as metal chlorides), or complexes containing at least one of metals, metal alloys, metal oxides, or metal halides.

[0040] As used herein, “electrocatalyst particle” or “electrochemical catalyst particle” refers to a catalyst particle that can reduce the activation energy required to carry out an electrochemical reaction and / or increase the rate of the electrochemical reaction, such as OER, HER, HOR, and / or ORR. Suitable electrocatalyst particles may include, but are not limited to, metals, such as platinum group metals (PGMs) (e.g., platinum, palladium, iridium, ruthenium, osmium, and rhodium), transition metals (e.g., silver, gold, cobalt, copper, iron, nickel, rhenium, and mercury), and post-transition metals (e.g., bismuth and tin); metal alloys (e.g., PGM-transition metal based alloys and platinum-ruthenium based alloys); metal oxides (e.g., PGM oxides, such as iridium(IV), ruthenium(IV), iridium-ruthenium oxide, platinum(IV), magnesium(IV), and cerium(IV)); metal halides (e.g., platinum(IV), iridium(III), platinum(IV), iridium(III)), and / or complexes of metals, metal alloys, metal oxides, and / or metal halides).

[0041] As used herein, “catalyst support” refers to a substance that does not contain catalyst particles but can be used to load catalyst particles (e.g., a substance or material on which catalyst particles may be bound or loaded). Examples of catalyst supports include, but are not limited to, carbon-based materials (e.g., carbon black, graphite, carbon nanotubes, graphene, and / or boron-functionalized carbon materials as described herein), titanium dioxide, antimony-doped tin dioxide nanoparticles, tin-doped indium oxide (ITO), and / or ion-exchange modified catalyst supports as described in International Patent Application No. PCT / US2022 / 046105, filed October 7, 2022, the entire contents of which are incorporated herein by reference.

[0042] As used herein, “catalyst” refers to catalyst particles, as well as the combination of catalyst particles and the catalyst support on which they are supported or bound. Catalysts may also contain catalyst additives, such as promoters (e.g., but not limited to metalloids).

[0043] As used herein, "electrocatalyst" or "electrochemical catalyst" refers to electrocatalyst particles in their "black" or pure form, as well as the combination of electrocatalyst particles and the catalyst support on which they are supported or bound. Electrocatalysts may also contain catalyst additives, such as promoters.

[0044] As used in this article, “metal” includes alkali metals, alkaline earth metals, transition metals, lanthanides, actinides, and post-transition metals.

[0045] As used in this article, "transition metals" refers to elements in the d-block of the periodic table (groups 3 to 12, including groups 3 and 12).

[0046] As used in this article, “post-transition metals” refers to aluminum, gallium, indium, tin, thallium, lead, bismuth, and polonium.

[0047] As used in this article, “metalloids” refers to boron, silicon, germanium, arsenic, antimony, tellurium, and astatine.

[0048] As used in this article, "platinum group metals" or "PGM" refers to platinum, palladium, iridium, ruthenium, osmium, and rhodium.

[0049] As used herein, "aliphatic" compounds refer to hydrocarbons that are saturated or unsaturated, acyclic or cyclic, unbranched or branched, unsubstituted or wholly or partially substituted by one or more substituents or functional groups. Those skilled in the art will understand that "aliphatic" herein is intended to include, but is not limited to, alkyl, alkenyl, and alkynyl moieties. Exemplary aliphatic groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, allyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, sec-pentyl, isopentyl, tert-pentyl, n-hexyl, and sec-hexyl moieties.

[0050] As used herein, the term "alkyl" has its conventional meaning in the art and can include saturated aliphatic groups, including straight-chain alkyl, branched alkyl, cycloalkyl (alicyclic), alkyl-substituted cycloalkyl, and cycloalkyl-substituted alkyl. Similar rules apply to other general terms such as "alkenyl," "alkynyl," etc. Furthermore, as used herein, the terms "alkyl," "alkenyl," "alkynyl," etc., cover both wholly and partially substituted groups and unsubstituted groups.

[0051] In some embodiments, the main chain of a straight-chain or branched alkyl chain may contain 1 to 30 carbon atoms, and in some cases may contain 1 to 20 or fewer carbon atoms. In some embodiments, the main chain of a straight-chain or branched alkyl chain contains 1 to 10 carbon atoms (e.g., straight chain C1-C10, branched chain C3-C10), 6 or fewer carbon atoms, or 4 or fewer carbon atoms. The cyclic structure of a cycloalkyl group may contain 3 to 10 carbon atoms, and in some cases may contain 3 to 5, 6, or 7 carbon atoms. Examples of acyclic alkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, n-butyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, n-decyl, n-undecyl, and dodecyl. Examples of cyclic alkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, and cyclohexyl.

[0052] The terms "alkenyl" and "alkynyl" refer to unsaturated aliphatic groups with similar lengths and possible substitutions to the alkyl groups described above, but each containing at least one double or triple bond. Alkenyl groups include, but are not limited to, for example, vinyl, propenyl, butenyl, 1-methyl-2-buten-1-yl, etc. Non-limiting examples of alkynyl groups include ethynyl, 2-propynyl (propynyl), 1-propynyl, etc.

[0053] The term "heteroatom" refers to any atom other than carbon. Non-limiting examples of heteroatoms include B, N, O, Al, Si, P, S, Ge, As, Se, and Sb. In some embodiments, a heteroatom is an atom selected from B, N, O, P, and S.

[0054] The term "heteroalkyl" refers to an alkyl group having one or more hydrogen atoms bonded to any carbon atom, or an alkyl group having one or more carbon atoms replaced by heteroatoms. Examples of heteroalkyl groups include, but are not limited to, methoxy, ethoxy, propoxy, isopropoxy, methylthio, ethylthio, propylthio, isopropylthio, n-butylthio, methoxymethyl, and cyano.

[0055] The terms “heteroalkenyl” and “heteroynyl” refer to unsaturated aliphatic groups that are similar in length and possible substitution modes to the heteroalkyl groups described above, but each contains at least one double or triple bond.

[0056] The term "aryl" refers to an unsubstituted or partially or fully substituted aromatic carbocyclic group, which may be monocyclic (e.g., phenyl), polycyclic (e.g., biphenyl), or polyfused-ring, wherein at least one ring of the aryl group is aromatic (e.g., 1,2,3,4-tetrahydronaphthyl, naphthyl, anthraceneyl, or phenanthryl). That is, at least one ring of the aryl group has a conjugated π-electron system, while the other rings of the aryl group may be cycloalkyl, cycloalkenyl, cycloynyl, aryl, and / or heterocyclic. "Carbocyclic aryl" refers to an aryl group whose ring atom is a carbon atom. Carbocyclic aryl groups include monocyclic carbocyclic aryl groups and polycyclic or fused-ring compounds (e.g., two or more adjacent ring atoms are shared by two adjacent rings), such as naphthyl. Aryl groups are not limited to benzene and its derivatives, and their rings may contain any suitable number of atoms. Examples of aryl groups include, but are not limited to, phenyl, naphthyl, tetrahydronaphthyl, aniline, indenyl, and indenyl.

[0057] The term "heteroaryl" refers to an aryl group (e.g., a heteroaromatic group) containing at least one heteroatom as a ring atom, such as a heterocyclic group. Non-limiting examples of heteroaryl groups include, but are not limited to, pyridyl, pyrazinyl, pyrimidinyl, pyrroleyl, pyrazolyl, imidazolyl, thiazolyl, oxazolyl, isoxazolyl, thiadiazolyl, oxadiazolyl, thiophenyl, furanyl, quinolinyl, and isoquinolinyl. A heteroaryl group may be referred to as "A-heteroaryl," where A is the element symbol for the heteroatom. For example, N-heteroaryl refers to an aryl group containing at least one nitrogen atom as a ring atom.

[0058] As used herein, the term "alkoxy" refers to an alkyl group with an oxygen group attached, having the general formula R-O. Examples of alkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy, and tert-butoxy.

[0059] The term "aryloxy group" refers to an aryl group that is attached to an oxygen group. Examples of aryloxy groups include, but are not limited to, phenoxy groups.

[0060] Any of the above groups may optionally be substituted, in whole or in part. Examples of substituents include, but are not limited to, aliphatic, alicyclic, heteroaliphatic, heterocyclocyclic, halogen, azide, alkyl, aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxyl, alkoxy, amino, amine, nitro, mercapto, imino, amide, phosphonate, hypophosphonate, carbonyl, carboxyl, alkoxycarbonyl, silyl, ether, alkylthio, heteroalkylthio, heteroarylthio, sulfonyl, sulfonamide, ketone, aldehyde, ester, heterocyclic, aromatic or heteroaromatic moiety, -CF3, -CN, aryl, aryloxy, perhaloalkoxy, arylalkoxy, heteroaryl, heteroaryloxy, heteroarylalkyl, heteroarylalkoxy, azide, amino, Halides, alkylthio, oxo, acylalkyl, carboxylic acid ester, -carboxamide, acyloxy, aminoalkyl, alkylaminoaryl, alkylaryl, alkylaminoalkyl, alkoxyaryl, arylamino, aralkylamino, alkylsulfonyl, -carboxamide alkylaryl, -carboxamide aryl, hydroxyalkyl, haloalkyl, alkylaminoalkylcarboxyl-, aminocarboxamide alkyl-, cyano, alkoxyalkyl, perhaloalkyl, arylalkoxyalkyl (e.g., SO4(R′)2), phosphate esters (e.g., PO4(R′)3), silanes (e.g., Si(R′)4), carbamates (e.g., R′O(CO)NHR′), etc. In addition, the substituents can be selected from F, Cl, Br, I, —OH, —NO2, —CN, —NCO, —CF3, —CH2CF3, —CHCl2, —CH2ORx, —CH2CH2ORx, —CH2N(Rx)2, —CH2SO2CH3, —C(O)Rx, —O2(Rx), —CON(Rx)2, —OC(O)Rx, —C(O)OC(O)Rx, —OCO2Rx, —OCON(Rx)2, —N(Rx)2, —S(O)2Rx, —OCO2Rx, —NRx(CO)Rx, —NR x (CO)N(R x )2, wherein each occurrence of Rx independently includes, but is not limited to, hydrogen, aliphatic, alicyclic, heteroaliphatic, heteroalicyclic, aryl, heteroaryl, alkylaryl or alkylheteroaryl, wherein any aliphatic, alicyclic, heteroaliphatic, heteroalicyclic, alkylaryl or alkylheteroaryl substituents described above and below may be wholly or partially substituted or unsubstituted, branched or unbranched, cyclic or acyclic, and any aryl or heteroaryl substituents described above and below may be wholly or partially substituted or unsubstituted.

[0061] Polytetrafluoroethylene (PTFE) polymers are a class of polymers composed of tetrafluoroethylene polymer molecules and their derivatives, prepared through the polymerization of tetrafluoroethylene. PTFE polymer molecules have a carbon backbone, with two fluorine atoms bonded to each carbon atom; its derivatives also have a similar structure.

[0062] Polychlorotrifluoroethylene (PCTFE) polymer is a derivative of PTFE and a homopolymer of chlorotrifluoroethylene (CTFE), with the molecular formula (CF2CClF). n PCTFE and its derivatives. PCTFE is similar to PTFE (such as Teflon), except that each repeating unit of PCTFE contains a chlorine atom. The presence of this chlorine atom makes PCTFE a unique thermoplastic polymer with a variety of applications. However, PCTFE has a hydrophobic backbone and lacks ionic conductivity, making it unsuitable for electrochemical applications. Derivatives of PCTFE polymers include polymers in which the chlorine atom is replaced by a substituent (e.g., a side chain or side group). PCTFE derivatives may be wholly or partially substituted. Derivatives of PCTFE polymers include, but are not limited to, modified and functionalized PCTFE polymers, including any modified or functionalized PCTFE polymers (e.g., acid-functionalized and ion-exchange-functionalized PCTFE polymers) described in U.S. Provisional Application No. 63 / 532,262, filed August 11, 2023, the entire contents of which are incorporated herein by reference.

[0063] Sulfonate-functionalized PTFE polymers are derivatives of PTFE polymers, having a PTFE backbone and side chains or side groups with one or more sulfonate side groups. In some embodiments, the side chain is a long side chain (LSC) having at least two ether bonds and four or more polyfluorocarbon units (e.g., —CF2— and / or —CF3). In other embodiments, the side chain is a short side chain (SSC) having one ether bond and two polyfluorocarbon units. In still other embodiments, the side chain is a medium side chain (MSC) having one ether bond and four polyfluorocarbon units. In some embodiments, the general formula of the sulfonate-functionalized PTFE polymer is [(CF2CF2)]. m (CFACF2) n ] xWhere A is a side chain containing one or more sulfonic acid side groups, and m, n, and x are all positive numbers selected based on factors such as application, equivalent weight, and molecular weight. In some embodiments, m ranges from 4 to 7, and n is 1. In some embodiments, side chain A is LSC, MSC, or SSC. Examples of LSC sulfonic acid-functionalized polytetrafluoroethylene polymers include, but are not limited to, the Nafion™ series of polymers (available from Chemours in various configurations and grades, including Nafion-H, NafionHP, Nafion117, Nafion115, Nafion212, Nafion211, NafionNE1035, NafionXL, etc.) and any combination, derivative, grade, or configuration thereof. Examples of SSC sulfonate-functionalized polytetrafluoroethylene polymers include, but are not limited to, the Aquivion® series of polymers (available from Solvay, in different configurations and grades, including Aquivion® E98-05, Aquivion® PW98, Aquivion® PW87S, etc.), Gore-Select® (available from WLGore & Associates), Flemion™ (available from Asahi Glass), Pemion+™ (available from Ionomr Innovations), and any combination, derivative, grade, or configuration thereof. Examples of MSC sulfonate-functionalized PTFE polymers include, but are not limited to, 3M. TM The company manufactures polymers. In some embodiments, the PTFE polymer is a copolymer containing one or more other repeating units. In some embodiments, the PTFE polymer may be doped and / or crosslinked with itself and / or other polymers.

[0064] Sulfonate-functionalized polymers include, but are not limited to, polyfluorosulfonic acid (PFSA) polymers and non-fluorinated sulfonate polymers. Examples of polyfluorosulfonic acid polymers include, but are not limited to, sulfonate-functionalized PTFE polymers and sulfonate-functionalized PCTFE polymers. Examples of non-fluorinated sulfonate polymers include, but are not limited to, poly(styrene sulfonate) polymers, sulfonated aromatic polymers (e.g., sulfonated poly(ether ketone) (SPEEK) polymers, sulfonated poly(aryl ether sulfone) (SPAES) polymers, sulfonated poly(aryl ether ketone) (SPAEK) polymers, sulfonated polysulfone (SPSF) polymers, sulfonated polyimide (SPI) polymers, sulfonated polystyrene (SPS), sulfonated polyphenylene, and any other sulfonated polymers, including sulfonated derivatives of the polymers described herein).

[0065] Polystyrene polymers are polymers composed of polystyrene polymer molecules. The repeating unit of a polystyrene polymer molecule contains alternating carbon centers, with a phenyl group bonded to each carbon center. Examples of polystyrene polymers include, but are not limited to, polystyrene, poly(styrene sulfonic acid) (e.g., poly(4-styrene sulfonic acid)), polyhalostyrene, poly(3-trifluoromethylstyrene), poly(4-acetoxystyrene), poly(4-allylstyrene), poly(4-cyanostrene), poly(4-dimethylsilylstyrene), poly(4-hydroxystyrene), poly(α-methylstyrene), poly(4-methylstyrene), poly(4-methoxystyrene), poly(4-[tert-butyloxycarbonyl]oxystyrene), and poly(4-tert-butyl... Polystyrene, poly(4-[N,N-di(trimethylsilyl)aminomethyl]styrene), poly(4-vinylbenzoic acid), poly(4-vinylbenzoic acid n-butyl ester), poly(4-vinylbenzoic acid tert-butyl ester), poly(4-vinylbenzoic acid 2-ethylhexyl ester), poly(4-vinylbenzoic acid methyl ester), poly(vinylbenzyl chloride), poly(4-vinylbenzyl-N-methylphthalimide), poly(vinylcyclohexane), and derivatives of any of the above polymers (including substituted (e.g., fluorinated) and / or branched derivatives). In some embodiments, the polystyrene polymer is a copolymer comprising one or more additional repeating units, which may or may not contain a carbon center bonded with a phenyl group.

[0066] Aromatic polymers are polymers containing one or more aromatic units in their main chain and / or side chains. The aromatic unit comprises one or more aryl and / or heteroaryl groups. Examples of aromatic polymers include, but are not limited to, polystyrene polymers, polycarbonate polymers (polyphenylene polymers, such as poly(1,4-phenylene), poly(1,4-phenylene-ethylene), poly(1,3-phenylene-methylene), poly(p-phenylenevinylene), poly(p-phenylenevinylene), poly(1,4-phenylene oxide), poly(1,4-phenylene sulfide)), poly(ether sulfone), polyaryl ether ketone polymers, polysulfone polymers, polyethylene terephthalate, and aromatic polyester polymers. Poly(oxy-1,4-phenylenecarbonyl-1,4-phenylene), poly[(dimethylmethylene)bis(4,1-phenylene)carbonate], phenolic resins, poly[(ethylazadiyl)ethyleneazadiyl-1,3-phenylene], polyoxydiphenyl pyromellitictetracarboximide (Kapton®, manufactured by DuPont), poly(esterimide) polymers, aromatic polyimide polymers, lignin, and derivatives of any of the above polymers (including substituted (e.g., fluorinated) and / or branched derivatives).

[0067] Conjugate acid proton exchange polymers are synthesized through an acid-base reaction following polymerization of a basic aromatic polymer with an acid. A basic aromatic polymer is a polymer containing basic aromatic units in its main chain and / or side chains. These basic aromatic units comprise basic aryl and / or basic heteroaryl groups. The acid-base reaction converts the basic aromatic unit into an acidic aromatic unit by protonation. This acidic aromatic unit is the conjugate acid of the basic aromatic unit and carries a formal positive charge due to the proton binding.

[0068] The resulting conjugated acid proton exchange polymer molecules contain acidic aromatic units in their main chain or side chains, and these acidic aromatic units are ionically bonded to counter anions. Common counter anions (such as sulfate from sulfuric acid, phosphate from phosphoric acid and polyphosphates, and halide ions) have strong coordination abilities. These coordinating anions can react with metal catalysts, leading to catalyst poisoning and promoting depolymerization, thereby reducing the yield and lifespan of membrane electrode assemblies (MEAs). The size of the counter anion, more specifically the ionic potential (the ratio of anion charge to anion radius), also plays a role in modulating the hydrogen bonding network and water retention capacity of the proton exchange membrane.

[0069] To address these issues, noncoordinate anions are chosen as the counter anions bonded to the acidic aromatic unit ions. Noncoordinate counter anions remain stable and inert under harsh electrochemical reaction conditions, do not cause catalyst poisoning due to reaction with metal catalysts, and do not participate in secondary depolymerization reactions. Therefore, in some embodiments, the counter anion bonded to the acidic aromatic unit ions is the conjugate base of the acid reagent used in the acid-base reaction, and the conjugate base of the acid reagent is a noncoordinate anion. In other embodiments (e.g., where the conjugate base of the acid reagent is coordinate), a subsequent fluoride treatment step is performed after the acid-base reaction to convert the counter anion into a noncoordinate counter anion (such as tetrafluoroborate or a metal fluoride); or a subsequent anion exchange step is performed after the acid-base reaction to exchange the counter anion for a noncoordinate counter anion (such as tetrafluoroborate). The fluoride treatment and anion exchange steps will be described in more detail below.

[0070] As previously mentioned, a basic aromatic unit comprises a basic aryl group and / or a basic heteroaryl group. Both basic aryl and basic heteroaryl groups contain an amino group whose lone pair electrons can accept a proton from an acid, making the aryl or heteroaryl group (and consequently the aromatic unit) weakly basic. The amino group can be located within the aromatic ring of the aromatic unit (e.g., the amino group in an N-heteroaryl group) or within a substituent of the aromatic ring (e.g., the amino group in an aromatic amine (aniline, for example)). The amino group can be a primary, secondary, or tertiary amine. As used herein, a primary amine refers to a nitrogen atom bonded to one carbon atom and two hydrogen atoms (C—N). Secondary amines are nitrogen atoms bonded to two carbon atoms and one hydrogen atom (C—NH—C); while tertiary amines are nitrogen atoms bonded to two carbon atoms and not to hydrogen atoms (C—N=C), or nitrogen atoms bonded to three carbon atoms (C—N(—C)(—C)). Tertiary amines in basic aromatic units are more basic than secondary amines in basic aromatic units, and secondary amines in basic aromatic units are more basic than primary amines in basic aromatic units.

[0071] Non-limiting examples of basic aromatic units include anilines (such as aniline, toluene, xylene, chloroaniline, aminobenzoic acid, nitroaniline, 2,5-diamino-1,4-phenylene), pyridines (such as 2,2'-bipyridine, 1,10-phenanthroline, 2,2';6'2"-terpyridine, 4-chloro-[3,3'-bipyridine]-5,5'-diyl, [2,3'-bipyridine]-4,5'-diyl, pyridine-4,2-diyl, pyridine-3,5-diyl, pyridine-2,4-diyl, pyridine-2,6-diyl), and pyrazines (such as alkylpyrazines, such as 2,3-dimethylpyrazine, 2,5-dimethylpyrazine). Pyrazines, 2,3,5-trimethylpyrazine, 2,6-dimethylpyrazine, 2-ethyl-3-methylpyrazine; methoxylated pyrazines, such as 3-isobutyl-2-methoxypyrazine), imidazoles (such as 1,5-dihydrobenzo[1,2-d:4,5-d']diimidazol-2,6-diyl, 4-phenyl-1H-imidazol-2,5-diyl, 4-phenyl-1H-imidazol-5,2-diyl, 5-phenyl-1H-imidazol-4,2-diyl), pyrazoles (such as 1H-pyrazole, 3H-pyrazole, 4H-pyrazole), aminopyrazoles (such as 3-aminopyrazoles, 4-aminopyrazoles, 5-aminopyrazoles), diaminopyrazoles (e.g., 3,5-diaminopyrazoles), 1-(1-adamantyl)pyrazoles, 1,4-di(1-adamantyl)pyrazoles, aminophenazone, metamizole), pyrimidines (e.g., 2,4-dioxanilidine, 2,4-dioxan-5-methylpyrimidine, 2-oxo-4-aminopyrimidine, 2,4-dioxan-6-carboxypyrimidine, 5-bromo-2,4-dichloropyrimidine), pyridazines, thiazoles (e.g., 6,6'-bi(1,3-benzothiazole)]-2,2'-diyl, [2,2'-bi(1,3-thiazole)]-4,4'-diyl), imidazoles Phosphates, quinolines (such as quinoline-2,4-diyl, [3,3'-biquinoline]-6,6'-diyl), isoquinolines, acridines, quinoxalines (such as 3,3'-diphenyl-[6,6'-biquinoxaline]-2,2'-diyl, 1H,1'H-[5,5'-bibenzimidazole]-2,2'-diyl), benzimidazoles, purines, indazoles, quinazolines, cyclophosphines, tetrazines (such as 1,2,4,5-tetraazine-3,6-diyl), thiophenes (such as 3,4-dioctylthiophene-2,5-diyl, thiophene-2,5-diyl, thiophene-2,4-diyl), and derivatives of any of the above substances.

[0072] Basic aromatic polymers include polymers formed by polymerization of monomer units containing any basic aromatic units, or polymers constructed based on or incorporated with any basic aromatic units. Non-limiting examples of basic aromatic polymers include polyaniline (PANI) polymers (including leucoemeraldine, emeraldine, and pernigranilin forms), polypyrrole (PPy), polypyridine polymers (such as poly(2-isopropenylpyridine), poly(2,5-pyridine), poly(3,5-pyridine), poly(2-vinylpyridine), poly(4-vinylpyridine)), polypyrazines (such as poly(2-vinylpyrazine)), polyimidazolium (such as poly(N-vinylimidazolium), poly(4-vinylimidazolium)), polypyrazole, polypyrimidine, polypyridazine (PPd), polythiazole, polyimidazoline, polyquinoline, polyisoquinoline, polyacridine, polyquinoxaline, polybenzimidazole, polypurine, polyinazole, polyquinazoline, polyoxoline, polytetraazine, and polymers containing basic aromatic units in the side chain or side group (such as poly(4-vinylpyridine) (PVP)).

[0073] An acid reagent donates a proton to a basic aromatic unit, generating a conjugate acid of the basic aromatic unit. Any suitable acid reagent can be used. In some embodiments, the conjugate base of the acid reagent is noncoordinate, thus the resulting counter anion remains stable and inert under harsh electrochemical reaction conditions, does not cause catalyst poisoning due to reaction with a metal catalyst, and does not participate in secondary depolymerization reactions. Non-limiting examples of suitable acids with noncoordinate conjugate bases include: Fluoroboric acid ( (also commonly referred to as tetrafluoroboric acid or hydrogen tetrafluoroborate) ][ ]), which has the following general formula structure: , Phenylacetic acid has the following general formula: , Phenyl-1,4-bis(trifluoro)boronic acid has the following general formula: , Hexafluorophosphate ( It has the following general formula structure: , Fluoroantimonic acid (also known as hexafluoroantimony hydrogen salt) It has the following general formula structure: , The sulfuric acid-boron trifluoride complex has the following general formula: , The benzenesulfonic acid-boron trifluoride complex has the following general formula: , Benzene disulfonic acid-boron trifluoride complex has the following general formula structure: , The phosphate-boron trifluoride complex has the following general formula: .

[0074] It should be understood that this disclosure also covers other acid reagents containing one or more fluoroboronic acid groups, which can be used in place of the acid reagents described above. In some embodiments, the noncoordinate conjugate base / anion generated by said acid reagent is tetrafluoroborate ([ ]), phenyl trifluoroborate ( ), hexafluorophosphate ([ ]), hexafluoroantimony ([ ]), benzenesulfonate-trifluoroborate ( ( ) ) or sulfate-bis(trifluoroborate) ( ( ) ).

[0075] In other embodiments, the conjugate base / counterion of the acid reagent is not noncoordinate. For example, sulfate, phosphate, and halide ions all have strong coordinating abilities. As described below, in the fluoride treatment step or anion exchange step, the coordinating counterion can be converted to a noncoordinate counterion, or the coordinating counterion can be replaced by a noncoordinate counterion. The acid reagent in such embodiments can be represented by the general formula HA, where A is a halide ion (such as F). Cl ,Br H , , , , , or polyphosphate anions derived from any polyphosphate. Suitable examples of polyphosphates include, but are not limited to, diphosphate, triphosphate, tetraphosphate, and trimetaphosphate. Non-limiting examples of acids HA include, but are not limited to, hydrofluoric acid (HF), hydrochloric acid (HCl), hydrobromic acid (HBr), and sulfuric acid (HBr). ), fluorophosphate ( ), phosphoric acid (or polyphosphate).

[0076] The degree of protonation of the basic aromatic unit can be adjusted to the desired level by regulating the molar ratio of the acid reagent to the basic aromatic unit in the polymer. For example, the molar ratio of the acid reagent to the basic aromatic unit can be 1:1, 1:2, 1:3, or any other suitable molar ratio. In some embodiments, the acid reagent is a limiting agent, such that the aromatic unit is not completely protonated. In other embodiments, the molar ratio of the acid reagent to the basic aromatic unit is greater than 1:1 (e.g., 1.5:1, 2:1, 3:1, etc.), such that the basic aromatic unit is completely protonated.

[0077] In acid-base reactions, the basic aromatic unit is protonated by the acid, transforming into an acidic aromatic unit. This acidic aromatic unit is the conjugate acid of the basic aromatic unit. Therefore, the polymer molecule formed by the acid-base reaction is called a conjugate acid polymer molecule. The acid-base reaction proceeds under standard conditions without a catalyst. During the reaction, the amine group in the basic aromatic unit undergoes protonation when its lone pair electron accepts a proton from the acid. Therefore, the acidic aromatic unit is an N-protonated conjugate acid. When the basic aromatic unit is an imidazole unit or a pyridine unit, the acidic aromatic unit (N-protonated conjugate acid) can be called an imidazole-onium unit or a pyridinium unit, respectively. When the basic aromatic unit contains aniline (such as in polyaniline polymers), the acidic aromatic unit (N-protonated conjugate acid) is an ammonium derivative. The acidic aromatic unit carries a positive charge on the protonated nitrogen atom and achieves charge balance by forming an ionic bond with a counter anion. This counter ion is the conjugate base of the acid reagent.

[0078] When the acid reagent is , When fluoroantimony is used, the counter ion is a noncoordinate counter anion (tetrafluoroborate, respectively). ]), hexafluorophosphate ([ ]) or hexafluoroantimonate ([ Therefore, such conjugated acid proton exchange polymers can be used in electrochemical applications.

[0079] In some embodiments, the use of acid reagents other than fluoroboronic acid can improve the ion exchange capacity (IEC) of the conjugated acid proton exchange polymer. In other embodiments, acid reagents containing multiple fluoroboronic acid groups (such as phenyltrifluoroboronic acid, phenyl-1,4-bis(trifluoro)boronic acid, sulfonic acid-) Complex, phosphate The complex can also act as a crosslinking agent, wherein each fluoroboronic acid group can react with different basic aromatic units of the same or different polymer molecules. Crosslinking in this way can simultaneously improve the durability and IEC of the resulting conjugated acid proton exchange polymer.

[0080] When the conjugate base of the acid reagent is coordinating, the intermediate conjugate acid proton exchange polymer needs to undergo a fluorination treatment step or an anion exchange step to convert the counter anion into a non-coordinating counter anion, or replace the counter anion with a non-coordinating counter anion.

[0081] For example, when the acid reagent is hydrofluoric acid (HF), the acid-base reaction produces an intermediate product, a conjugated acid proton exchange polymer, whose counter ion is a fluoride anion (F). - The subsequent fluorination process involves reacting the intermediate conjugated acid proton exchange polymer with boron trifluoride (e.g., boron trifluoride in ether). (Form), a mixture of difluoro(phenyl)boranes having any of the following general formulas: and , Or the general formula is MF n Metal fluorides, where M is beryllium (Be), aluminum (Al), bismuth (Bi), antimony (Sb), phosphorus (P), tin (Sn), zirconium (Zr), or titanium (Ti), and n is the valence of M. Boron trifluoride combines with fluoride anions via an addition reaction to form a noncoordinate tetrafluoroborate counter anion, wherein the oxidation state of M is increased to bind the fluoride anion. Similarly, the above-mentioned difluoro(phenyl)borane combines with fluoride anions via an addition reaction to form a noncoordinate trifluoro(phenyl)borate counter anion. Metal fluorides combine with fluoride anions via an addition reaction to form the general formula [MF]. (n+1) ] The noncoordinate metal fluoride counter anion is formed by increasing the oxidation state of M to bind fluoride ions. In some embodiments, the noncoordinate metal fluoride counter anion is beryllium fluoride (BF2). ), aluminum fluoride ( ), bismuth fluoride (such as bismuth trifluoride ( ), antimony fluoride (such as antimony trifluoride ( )), antimony ... Phosphorus fluoride (such as monofluorophosphate, difluorophosphate, or hexafluorophosphate), tin fluoride (tin difluoride, also known as tin fluoride), zirconium fluoride (such as zirconium tetrafluoride) )) or titanium fluoride (such as titanium trifluoride ( ) and titanium tetrafluoride ( )).

[0082] In some embodiments, the use of difluoro(phenyl)borane in the fluorination treatment step can improve the ion exchange capacity (IEC) of the conjugated acid proton exchange polymer compared to the use of boron trifluoride. In some embodiments, difluoro(phenyl)borane having two difluoroboron groups can also act as a crosslinking agent, wherein each difluoroboron group can crosslink different aromatic units of the same or different polymer molecules. Crosslinking in this way can simultaneously improve the durability and IEC of the resulting conjugated acid proton exchange polymer.

[0083] In other embodiments, when the acid reagent is an acid represented by the above general formula HA, the acidic aromatic unit in the intermediate product conjugated acid proton exchange polymer generated by the acid-base reaction interacts with the noncoordinate counterion A. Ionic bonding. This is followed by an anion exchange step: the intermediate conjugated acid proton exchange polymer is bonded to... (The text abruptly ends here, likely due to an incomplete sentence or a missing section.) A mixture of tetrafluoroborate metal compounds, in which M is a tetrafluoroborate anion, and M is a sodium ion ( ), potassium ions ( ), cesium ions ( ), ammonium ( ) or tetraalkylammonium ( Each R is independently hydrogen, or a fully substituted, partially substituted, or unsubstituted alkyl group containing 1 to 20, 1 to 10, 1 to 8, 1 to 6, or 1 to 4 carbon atoms (e.g., but not limited to methyl, ethyl, propyl, or butyl). The metal ion M and the counter anion A... They combine to form salts with the general formula MA, while the tetrafluoroborate anion ( ) replace A This becomes a counterion that binds to the acidic aromatic unit. Therefore, the anion exchange step ultimately yields a conjugated acid proton exchange polymer that is ionically bonded to the noncoordinate tetrafluoroborate counterion anion.

[0084] In some embodiments, the conjugated acid proton exchange polymer (CAEP) is conductive in addition to proton conductivity. In such embodiments, the CAEP is prepared from a conductive polymer (such as polyaniline or polypyrrole polymer). In other embodiments, the CAEP is not conductive. In such embodiments, the CAEP is prepared from a non-conductive polymer.

[0085] The following section will use a weakly basic PBI polymer as an example to illustrate how to convert a weakly basic polymer into a proton-conductive conjugate acid polymer, but the principles described herein can be applied to any other basic aromatic polymer.

[0086] PBI polymers are a class of polymers composed of PBI polymer molecules. In the repeating units of a PBI polymer molecule, the main chain contains at least one benzimidazole unit. The benzimidazole unit comprises a benzimidazole moiety or a derivative thereof. Benzimazole is a heterocyclic aromatic organic compound in which the phenyl and imidazole groups share two carbon atoms in their rings. The general formula of benzimidazole is shown in formula (I): (I).

[0087] Examples of PBI polymers containing one benzimidazole unit in the main repeating unit are poly(2,5-benzimidazole) (AB-PBI), as shown in formula (II); examples of PBI polymers containing two benzimidazole units in the main repeating unit include poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole] (m-PBI), as shown in formula (III); and fluorinated derivatives of 4F-PBI (m-PBI), as shown in formula (IV). (II): (AB-PBI), (III): (m-PBI), (IV): (4F-PBI).

[0088] Other examples of PBI polymers include, but are not limited to: poly{2,6-(2,6-naphthylene)-1,7-dihydrobenzo[1,2-d;4,5-d']diimidazole}, poly2,2'-(2,6-naphthylene)-5,5'-bibenzimidazole, poly-2,2'-(2,6-pyridine)-5,5'-bibenzimidazole, poly-2,2'-(2,5-pyridine)-5,5'-bibenzimidazole, poly-2,2'-(2,2'-bipyridine-5,5')-5,5'-bibenzimidazole, poly-2 2'-(3,5-pyrazole)-5,5'-bibenzimidazole, poly-2,2'-(m-phenylene)-5,5'-bibenzimidazole, poly-2,2'-(pyridyl-3",5")-5,5'-bibenzimidazole, poly-2,2'-(furanyl-2",5")-5,5'-bibenzimidazole, poly-2,2-(naphthalene-1",6")-5,5'-bibenzimidazole, poly-2,2'-(biphenyl-4",4")-5,5'-bibenzimidazole, poly-2,2'-pentylene- 5,5'-Bibenzimidazole, poly-2,2'-octyl-5,5'-bibenzimidazole, poly-2,6-(m-phenylene)-diimidazolebenzene, poly-2,2'-cyclohexenyl-5,5'-bibenzimidazole, poly-2,2'-(m-phenylene)-5,5-di(benzimidazole) ether, poly-2,2'-(m-phenylene)-5,5-di(benzimidazole) sulfide, poly-2,2'-(m-phenylene)-5,5-di(benzimidazole) sulfone, poly-2,2'-(m-phenylene)-5,5-di( The polymers are benzimidazole (BBI)methane, poly-2,2"-(m-phenylene)-5",5"-di(benzimidazole)propane-2,2, poly-2,2"-(m-phenylene)-5',5"-di(benzimidazole)ethylene-1,2, and derivatives of any of the above polymers (including substituted (e.g., fluorinated) and / or branched derivatives). In some embodiments, the PBI polymer is a copolymer containing one or more additional repeating units, which may or may not contain benzimidazole units in the main chain, side chains, or both.

[0089] PBI polymers are weakly basic and can be converted into stable acidic polymers through a simple acid-base conjugation reaction and treatment with a strong acid. The resulting polybenzimidazole-onium polymer (referred to as "PBI polymers" in this paper) The polymer has an acidic aromatic unit, which is the conjugate acid of the weakly basic aromatic unit in the original PBI polymer. The polymer is ionic and strongly acidic, thus exhibiting high cationic conductivity. Under aqueous conditions in water electrolysis and hydrogen fuel cells, the polybenzimidazole onium unit readily dissociates, forming neutral PBI and hydrated protons (PBI). The equilibrium mixture of ) . Therefore, the easily dissociable polybenzimidazole onium unit can serve as a proton transport agent. Thus, The polymer can be used in ionomers and proton exchange membrane (PEM) applications. Acidic. Polymers are simple and advanced alternatives to existing polyphosphoric acid (PPA) doped polymers, such as PBI-PPA.

[0090] In PBI polymer molecules, the tertiary amine of the benzimidazole unit (such as N in the N=C group) reacts with a strong acid through an acid-base reaction to generate a benzimidazole onon unit (the conjugate acid of the weakly basic benzimidazole unit) and a counter anion (the conjugate base of the strong acid) that is ionically bonded to the benzimidazole onon unit.

[0091] The molecular structure of the polymer indicates that the noncoordinate counter anion does not play a direct role in the electrochemical reaction, as its main function is neutralization. The polymer structure contains a positive charge. Therefore, noncoordinate counter anions do not directly or indirectly participate in electrochemical reaction processes, nor do they inhibit catalytic cycles by binding with metal catalysts.

[0092] In some implementations, the counter anions include tetrafluoroborate ([ This is a noncoordinate anion containing tetravalent boron, which remains stable and inert during electrochemical reactions. Other suitable counter anions may include, for example, hexafluorophosphate ([ ]), hexafluoroantimony ([ ]) , Bismuth fluoride, antimony fluoride, phosphorus fluoride, tin fluoride, zirconium fluoride and / or titanium fluoride.

[0093] The article described The polymers are inherently ionic, similar to ionic liquids known to accelerate / promote electrochemical reactions. Exemplary proton conductivity will be described below. Polymers and their preparation methods.

[0094] Figure 1 This demonstrates the preparation of proton conductivity that is ionically bonded to tetrafluoroborate counter anions. Exemplary reaction schemes for polymers. For example... Figure 1 As shown, the m-PBI polymer is reacted with tetrafluoroboric acid ( The mixture. Tetrafluoroboric acid is a very strong acid that combines with the tertiary nitrogen atom of the benzimidazole unit via an acid-base reaction. This reaction generates a benzimidazole ononium unit and a tetrafluoroborate counterion ion bonded to this benzimidazole ononium unit. The benzimidazole unit is the strong conjugate acid of the weakly basic aromatic benzimidazole unit; the tetrafluoroborate counter anion is the conjugate base of tetrafluoroboric acid. The tetrafluoroborate counter anion contains a tetravalent boron atom, and is therefore non-coordinated and non-oxidizing, making it highly stable under the harsh electrochemical conditions of electrochemical battery applications such as water electrolysis and fuel cells. The tetrafluoroborate counter anion also does not combine with metal catalysts, thus preventing catalyst poisoning.

[0095] exist Figure 1 In one embodiment, only one benzimidazole unit in each repeating unit is converted to a benzimidazole-onium unit. In other embodiments, both benzimidazole units in each repeating unit are converted to benzimidazole-onium units. In yet another embodiment, this can be controlled... The molar ratio to the benzimidazole unit allows for control of the proton loading level as needed.

[0096] Figure 2 This demonstrates the preparation of ionic bonds with tetrafluoroborate counter anions. Another exemplary reaction scheme for the polymer. In the first step, m-PBI is mixed with hydrofluoric acid (HF). Hydrofluoric acid is a very strong acid that binds to the tertiary nitrogen atom of the benzimidazole unit via an acid-base reaction. The first step reaction generates an intermediate product. The polymer, in which the benzimidazolium unit is ionically bonded to the fluoride ion counterion anion. The second step (fluoride treatment step) involves the intermediate product... Polymers with boron trifluoride (e.g., diethyl ether) (Boron trifluoride form) is mixed. Boron trifluoride combines with fluoride counterions to form tetrafluoroborate counterions, ultimately yielding a mixture containing benzimidazolium units ionically bonded to tetrafluoroborate counterions. polymer.

[0097] Figure 3 This demonstrates the preparation of ions that bond with any one of a variety of different counter anions. An exemplary reaction scheme for the polymer. In the first step, m-PBI is mixed with hydrofluoric acid (HF). Hydrofluoric acid is a very strong acid that binds to the tertiary nitrogen atom of the benzimidazole unit via an acid-base reaction. The first step reaction generates an intermediate product. The polymer, in which the benzimidazolium unit is ionically bonded to the fluoride ion counterion anion. The second step (fluoride treatment step) involves the intermediate product... Polymers and those with the general formula MF n A mixture of metal fluorides (where M is beryllium (Be), aluminum (Al), bismuth (Bi), antimony (Sb), phosphorus (P), tin (Sn), zirconium (Zr), or titanium (Ti), and n is the valence of M). The metal fluoride combines with the counterion of fluoride ions to form a mixture of metal fluorides with the general formula [MF].(n+1) ] The counter anion, thereby generating a strongly acidic substance bonded to the counter anion. polymer.

[0098] Figure 4 This demonstrates the preparation of ionic bonds with tetrafluoroborate counter anions. Another exemplary reaction scheme for the polymer. The first step involves mixing m-PBI with an acid of the general formula HA, where A is fluorine (F), chlorine (Cl), bromine (Br), or H₂. , , , , This can be an anion of any type of polyphosphate, or derived from any type of polyphosphate. Suitable examples of polyphosphates include, but are not limited to, diphosphates, triphosphates, tetraphosphates, and trimetaphosphates. The acid HA combines with the tertiary nitrogen atom of the benzimidazole unit via an acid-base reaction. The first step of the reaction yields an intermediate product. Polymers whose benzimidazolium units and counter anions A Ion bonding. The second step (anion exchange step) involves the counterion A... The exchange is for tetrafluoroborate counter anion ([ [), which is a non-coordinating counter anion. The second step is as follows: the intermediate product Polymers and general formula A mixture of tetrafluoroborate metal compounds, in which It is a tetrafluoroborate anion ( ), and M is sodium ion ( ), potassium ions ( ), cesium ions ( ), ammonium ( ) or tetraalkylammonium ( Each R is independently hydrogen, or a fully substituted, partially substituted, or unsubstituted alkyl group, which may contain 1 to 20, 1 to 10, 1 to 8, 1 to 6, or 1 to 4 carbon atoms, such as, but not limited to, methyl, ethyl, propyl, or butyl. The tetrafluoroborate metal compound combines with the fluoride counter anion to form a tetrafluoroborate counter anion, thereby producing a strongly acidic compound ionically bonded to the noncoordinate tetrafluoroborate counter anion. polymer.

[0099] The above embodiments and reaction schemes can be extended to other applications, including crosslinking fluoroboronic acid-functionalized polymers with basic aromatic polymers to form conjugated acid proton exchange polymers. In some embodiments, the fluoroboronic acid-functionalized polymer is a fluoroboronic acid-functionalized sulfonic acid polymer, which includes sulfonic acid-functionalized polymers (such as Nafion™ and Aquivion® polymers), wherein one or more sulfonic acid side groups are coupled with... The reaction forms a fluoroboronic acid side group (— in one or more side chains or side groups) H) has the following structure: .

[0100] The fluoroboronic acid-functionalized polymer is mixed with a basic aromatic polymer (such as PBI, PANI, or any other basic aromatic polymer described herein). The fluoroboronic acid side groups are arranged in a manner similar to... Figure 1 The cross-linking process involves an acid-base reaction between the fluoroboric acid-functionalized polymer and the basic aromatic unit of a basic aromatic polymer, thereby cross-linking the fluoroboric acid-functionalized polymer with the basic aromatic polymer. The cross-linked conjugated acid proton exchange polymer molecule comprises: a first polymer molecule containing an acidic aromatic unit, wherein the acidic aromatic unit is the conjugate acid of the basic aromatic unit; and a second polymer molecule containing a trifluoroborate group, wherein the trifluoroborate group is the conjugate base of the fluoroboric acid group. The first polymer molecule and the second polymer molecule are cross-linked through ionic bonds between the acidic aromatic unit and the trifluoroborate group. Examples of cross-linked conjugated acid proton exchange polymers include, but are not limited to, those mentioned above. - PFSA (perfluorosulfonic acid) polymers (such as -Nafion™ polymers, -Aquivion® polymer), SPSF (sulfonated polysulfone) polymer, - SPEEK (sulfonated polyetherketone) polymers, PANI-PFSA polymers (such as PANI-Nafion™ polymers, PANI-Aquivion® polymers), PANI-SPSF polymers, PANI-SPEEK polymers, PPy-PFSA polymers (such as PPy-Nafion™ polymers, PPy-Aquivion® polymers), PPy-SPSF polymers, and PPy-SPEEK polymers. In some embodiments, two or more polymers may be crosslinked (e.g., three or four polymers).

[0101] It should be understood that, in addition to fluoroboric acid-functionalized sulfonic acid polymers, other fluoroboric acid-functionalized polymers can also crosslink with basic aromatic polymers. Fluoroboric acid-functionalized polymers include any polymer containing fluoroboric acid side groups, such as, but not limited to, any fluoroboric acid-functionalized polymers described in International Patent Application PCT / US2024 / 015409, filed February 12, 2024, the entire contents of which are incorporated herein by reference. Crosslinking fluoroboric acid-functionalized polymers with basic aromatic polymers in this manner improves the dimensional stability of crosslinked conjugated acid proton exchange polymers.

[0102] Figure 5 An exemplary proton exchange membrane water electrolysis system 500 (PEM water electrolysis system 500) is shown, which integrates a conjugated acid proton exchange polymer proton exchange membrane (PEM) and / or ionomer (such as... Polymer PEM and / or ionomers). The PEM water electrolysis system 500 uses electrical energy to decompose water into oxygen through an electrochemical reaction. ) and hydrogen ( The structure of the PEM water electrolysis system 500 is merely exemplary and not limiting; other suitable water electrolysis systems may also integrate conjugated acid proton exchange polymers.

[0103] like Figure 5 As shown, the PEM water electrolysis system 500 includes a membrane electrode assembly 502 (MEA 502), porous transport layers 504-1 and 504-2 (such as gas diffusion layers), bipolar plates 506-1 and 506-2, and a power supply 508. Depending on specific application requirements, the PEM water electrolysis system 500 may also include... Figure 5 Other additional or alternative components not shown in the diagram.

[0104] MEA 502 includes a PEM 510 located between a first catalyst layer 512-1 and a second catalyst layer 512-2. The PEM 510 provides electrical isolation between the first catalyst layer 512-1 and the second catalyst layer 512-2, while allowing cations (such as protons) to pass through. Selective conduction and prevention of gas permeation such as hydrogen and oxygen. PEM 510 can be made from the conjugated acid proton exchange polymers described herein (such as... It is made of polymers, or other suitable polymers.

[0105] The first catalyst layer 512-1 and the second catalyst layer 512-2 are conductive electrodes, comprising a catalyst solid support in which electrocatalyst particles (not shown) are bonded, such as platinum group metals, metal alloys, and / or metal oxides. The first catalyst layer 512-1 and the second catalyst layer 512-2 may also contain one or more ionomers, which are mixed with the catalyst solid support and the electrocatalyst particles. The ionomers may be derived from the conjugated acid proton exchange polymers described herein (such as...). It can be made from polymers, or other suitable ionomers. In some embodiments, the ionomer is made from a conductive conjugated acid proton exchange polymer (such as a conjugated acid proton exchange polyaniline polymer).

[0106] MEA 502 is placed between porous transport layers 504-1 and 504-2, which are in turn placed between bipolar plates 506-1 and 506-2. Flow channels 514-1 and 514-2 are provided between bipolar plates 506 and porous transport layer 504.

[0107] In MEA 502, the first catalyst layer 512-1 serves as the anode, while the second catalyst layer 512-2 serves as the cathode. When power supply 508 supplies power to the PEM water electrolysis system 500, the oxygen evolution reaction (OER) occurs on the first catalyst layer / anode 512-1. This reaction is promoted by an electrocatalyst bonded to the catalyst solid support of the first catalyst layer / anode 512-1. The OER can be represented by the following electrochemical half-reaction: 2 O→ +4 +4e .

[0108] Protons are conducted from the first catalyst layer / anode 512-1 to the second catalyst layer / cathode 512-2 through PEM 510, while electrons are conducted from the first catalyst layer / anode 512-1 to the second catalyst layer / cathode 512-2 through the conductive pathway on the outside of PEM 510. PEM 510 allows protons ( Water is transported from the first catalyst layer / anode 512-1 to the second catalyst layer / cathode 512-2, but oxygen and hydrogen permeation is prevented. On the second catalyst layer / cathode 512-2, protons and electrons combine in the hydrogen evolution reaction (HER), which is promoted by an electrocatalyst bonded to a solid catalyst support on the second catalyst layer / cathode 512-2. HER can be represented by the following electrochemical half-reaction: 4 +4e →2 .

[0109] OER and HER are two complementary electrochemical reactions in the process of water electrolysis. The overall water electrolysis reaction can be represented as: 2 O→2 + .

[0110] Figure 6 An exemplary proton exchange membrane fuel cell 600 (PEM fuel cell 600) is shown, which comprises a conjugated acid proton exchange polymer PEM and / or an ionomer (such as... Polymer PEM and / or ionomers). The PEM fuel cell 600 generates electrical energy through an electrochemical reaction. In this embodiment, the electrochemical reaction involves hydrogen ( ) and oxygen ( The reaction produces water and generates electricity. The structure of the PEM fuel cell 600 is merely exemplary and not limiting.

[0111] like Figure 6 As shown, the PEM fuel cell 600 includes a membrane electrode assembly 602 (MEA 602), porous transport layers 604-1 and 604-2 (such as a gas diffusion layer), and bipolar plates 606-1 and 606-2. An electrical load 608 can be electrically connected to the MEA 602 and driven by the PEM fuel cell 600. Depending on specific application requirements, the PEM fuel cell 600 may also include... Figure 6 Other additional or alternative components not shown in the diagram.

[0112] MEA 602 includes a PEM 610 located between a first catalyst layer 612-1 and a second catalyst layer 612-2. The PEM 610 provides electrical isolation between the first catalyst layer 612-1 and the second catalyst layer 612-2, while allowing cations (such as protons) to pass through. It selectively conducts gas and prevents the permeation of gases such as hydrogen and oxygen. PEM 610 can be made from any suitable proton exchange membrane described herein, including any conjugated acid proton exchange polymer described or mentioned herein.

[0113] The first catalyst layer 612-1 and the second catalyst layer 612-2 are conductive electrodes, comprising a catalyst solid support in which electrocatalyst particles (not shown) are bonded, such as platinum group metals, metal alloys, and / or metal oxides. The first catalyst layer 612-1 and the second catalyst layer 612-2 may also contain one or more ionomers, which are mixed with the catalyst solid support and the electrocatalyst particles. The ionomers may be made from any suitable polymer or ionomer described herein (including any conjugated acid proton exchange polymer described herein), or from other suitable ionomers. In some embodiments, the ionomers are made from conductive conjugated acid proton exchange polymers (such as conjugated acid proton exchange polyaniline polymers).

[0114] MEA 602 is positioned between porous transport layers 604-1 and 604-2, which in turn are positioned between bipolar plates 606-1 and 606-2. A flow channel 614 is provided between the bipolar plates and the porous transport layers. In MEA 602, the first catalyst layer 612-1 serves as the cathode, and the second catalyst layer 612-2 serves as the anode. Both the first catalyst layer / cathode 612-1 and the anode 612-2 are electrically connected to the load 608, and the electrical energy generated by the PEM fuel cell 600 drives the load 608.

[0115] When the PEM fuel cell 600 is running, hydrogen ( ) flows into the anode side of the PEM fuel cell 600, while oxygen ( Hydrogen molecules flow into the cathode side of the PEM fuel cell 600. On the second catalyst layer / anode 612-2, hydrogen molecules are catalytically split into protons according to the following hydrogen oxidation reaction (HOR). ) and electrons (e The electrocatalyst particles bound to the solid support in the second catalyst layer / anode 612-2 promote the hydroxide oxidizing reaction (HOR): 2 →4 +4e .

[0116] Protons are conducted from the anode 612-2 to the first catalyst layer / cathode 612-1 via PEM600, while electrons are conducted from the second catalyst layer / anode 612-2 to the first catalyst layer / cathode 612-1 via the conductive path outside PEM610 and the load 608. On the first catalyst layer / cathode 612-1, protons and electrons mix with oxygen according to the oxygen reduction reaction (ORR), and the electrocatalyst particles on the solid support in the first catalyst layer / cathode 612-1 promote this oxygen reduction reaction: +4 +4e →2 O.

[0117] Therefore, the overall electrochemical reaction of the PEM fuel cell 600 is: 2 + →2 O.

[0118] In the overall reaction, the PEM fuel cell 600 generates water at the first catalyst layer / cathode 612-1. The water can be transported from the first catalyst layer / cathode 612-1 to the second catalyst layer / anode 612-2 via the PEM 610, and can be discharged through outlets on the cathode side and / or anode side of the PEM fuel cell 600. The overall reaction generates electrons at the anode, which drive the load 608.

[0119] In Figure 14 and Figure 5 In the embodiments described, MEA 502 and MEA 602 comprise catalyst layers 512 / 412 formed on PEM 510 / 410. In other alternative structures, catalyst layers 512 / 412 may be coated onto PEM 110 / 410 to form a catalyst coated film (CCM). For example, catalyst layers 512 / 212 may be prepared by a one-pot or stepwise process and then sprayed onto PEM 510 / 410.

[0120] This article has already described the applications of conjugated acid proton exchange polymers (PEMs) in electrochemical cells, such as water electrolysis and hydrogen fuel cells. However, PEMs can also be used in other applications. For example, the pKa of PEMs can be tuned to levels required for specific applications, including electrochemical processes for ammonia synthesis. Specifically, the pKa of PEMs can be tuned to a higher level than that of conventional PEMs used in current ammonia synthesis processes.

[0121] This document has described and illustrated various embodiments and implementations. However, various modifications and alterations can be made thereto without departing from the scope of the following claims, and additional implementations may also be implemented. For example, a particular feature of one embodiment described herein may be combined with or substituted with a feature of another embodiment. Therefore, this specification and drawings should be considered illustrative rather than restrictive.

[0122] The advantages and features of this disclosure can be further illustrated by the following embodiments: Implementation Scheme 1. A conjugated acid proton exchange polymer molecule comprising: an acidic aromatic unit in the main chain or side chain, wherein the acidic aromatic unit is a conjugated acid of a basic aromatic unit; and a noncoordinate counter anion ionically bonded to the acidic aromatic unit.

[0123] Implementation Scheme 2. The conjugate acid proton exchange polymer molecule according to Implementation Scheme 1, wherein the noncoordinate counter anion is the conjugate base of a strong acid.

[0124] Implementation Scheme 3. The conjugated acid proton exchange polymer molecule according to Implementation Scheme 1, wherein the noncoordinating counter anion comprises tetrafluoroborate.

[0125] Implementation Scheme 4. The conjugated acid proton exchange polymer molecule according to Implementation Scheme 1, wherein the noncoordinating counter anion comprises hexafluorophosphate.

[0126] Implementation Scheme 5. The conjugated acid proton exchange polymer molecule according to Implementation Scheme 1, wherein the noncoordinating counter anion comprises hexafluoroantimonate.

[0127] Implementation Scheme 6. The conjugated acid proton exchange polymer molecule according to Implementation Scheme 1, wherein the noncoordinating counter anion comprises benzenesulfonate-trifluoroborate ( ( ) ).

[0128] Implementation Scheme 7. The conjugated acid proton exchange polymer molecule according to Implementation Scheme 1, wherein the noncoordinating counter anion comprises sulfate-bis(trifluoroborate) ( ( ) ).

[0129] Option 8. The conjugated acid proton exchange polymer molecule according to embodiment 1, wherein the noncoordinating counter anion comprises beryllium fluoride, aluminum fluoride, bismuth fluoride, antimony fluoride, phosphorus fluoride, tin fluoride, zirconium fluoride, or titanium fluoride.

[0130] Implementation Scheme 9. The conjugated acid proton exchange polymer molecule according to Implementation Scheme 1, wherein the noncoordinating counter anion comprises the general formula [MF (n+1) ] The metal fluoroborate ion, wherein M is beryllium (Be), aluminum (Al), bismuth (Bi), antimony (Sb), phosphorus (P), tin (Sn), zirconium (Zr) or titanium (Ti), and n is the valence of M.

[0131] Implementation Scheme 10. The conjugated acid proton exchange polymer molecule according to Implementation Scheme 1, wherein the basic aromatic unit comprises aniline or an aniline derivative.

[0132] Implementation Scheme 11. The conjugated acid proton exchange polymer molecule according to Implementation Scheme 1, wherein the basic aromatic unit comprises an imidazole group or a benzimidazole group.

[0133] Implementation Scheme 12. The conjugated acid proton exchange polymer molecule according to Implementation Scheme 1, wherein the conjugated acid proton exchange polymer molecule is conductive.

[0134] Implementation Scheme 13. A method for preparing a conjugate acid proton exchange polymer molecule, comprising: protonating a basic aromatic unit of a basic aromatic polymer molecule to form an acidic aromatic unit, wherein the acidic aromatic unit is the conjugate acid of the basic aromatic unit; and ionically bonding a noncoordinate counter anion to the acidic aromatic unit.

[0135] Implementation Scheme 14. The method according to Implementation Scheme 13, wherein protonating the basic aromatic unit and ion bonding the noncoordinating counter anion to the acidic aromatic unit comprises causing the basic aromatic unit to undergo an acid-base reaction with an acid, wherein the conjugate base of the acid contains the noncoordinating counter anion.

[0136] Implementation Scheme 15. The method according to Implementation Scheme 14, wherein the acid comprises fluoroboric acid.

[0137] Implementation Scheme 16. The method according to Implementation Scheme 14, wherein the acid comprises hexafluorophosphate.

[0138] Implementation Scheme 17. The method according to Implementation Scheme 14, wherein the acid comprises fluoroantimonyic acid.

[0139] Implementation Scheme 18. The method according to Implementation Scheme 14, wherein the acid comprises a sulfuric acid-boron trifluoride complex having the following general formula: .

[0140] Implementation Scheme 19. The method according to Implementation Scheme 14, wherein the acid comprises a benzenesulfonic acid-boron trifluoride complex having the following general formula: .

[0141] Implementation Scheme 20. The method according to Implementation Scheme 14, wherein the acid comprises a benzene disulfonic acid-boron trifluoride complex having the following general formula: .

[0142] Implementation Scheme 21. The method according to Implementation Scheme 14, wherein the acid comprises phenyltrifluoroboronic acid having the following general formula: , Or phenyl-1,4-bis(trifluoro)boronic acid having the following general formula: .

[0143] Implementation Scheme 22. The method according to Implementation Scheme 14, wherein the acid comprises a phosphate-boron trifluoride complex having the following general formula: .

[0144] Implementation Scheme 23. The method according to Implementation Scheme 13, wherein protonating the basic aromatic unit comprises reacting the basic aromatic unit with hydrofluoric acid in an acid-base reaction, wherein the conjugate base of the hydrofluoric acid comprises a fluoride counterion bonded to the acidic aromatic unit ion; and bonding the noncoordinate counterion to the acidic aromatic unit ion comprises reacting the fluoride counterion with boron trifluoride.

[0145] Implementation Scheme 24. The method according to Implementation Scheme 13, wherein protonating the basic aromatic unit comprises reacting the basic aromatic unit with hydrofluoric acid in an acid-base reaction, wherein the conjugate base of the hydrofluoric acid comprises a fluoride counter anion ionically bonded to the acidic aromatic unit; and bonding the noncoordinate counter anion to the acidic aromatic unit ion comprises bonding the fluoride counter anion with a general formula MF n The reaction of metal fluorides, where M is beryllium (Be), aluminum (Al), bismuth (Bi), antimony (Sb), phosphorus (P), tin (Sn), zirconium (Zr) or titanium (Ti), and n is the valence of M.

[0146] Implementation Scheme 25. The method according to Implementation Scheme 13, wherein protonating the basic aromatic unit comprises reacting the basic aromatic unit with an acid in an acid-base reaction, wherein the conjugate base of the acid comprises a coordinating counter anion ion bonded to the acidic aromatic unit; and bonding the non-coordinating counter anion with the acidic aromatic unit ion comprises performing an anion exchange reaction to exchange the coordinating counter anion for the non-coordinating counter anion.

[0147] Implementation Scheme 26. The method according to Implementation Scheme 25, wherein the acid has the general formula HA, where A is F, Cl, Br, H. , , H , Or polyphosphate anions.

[0148] Implementation Scheme 27. The method according to Implementation Scheme 25, wherein the anion exchange reaction comprises making the general formula as follows: The tetrafluoroborate metal compound reacts, where M is a sodium ion ( ), potassium ions ( ), cesium ions ( ), ammonium ( ) or general formula is Tetraalkylammonium, wherein each R is independently hydrogen, or a fully substituted, partially substituted, or unsubstituted alkyl group.

[0149] Implementation Scheme 28. The method according to Implementation Scheme 13, wherein the basic aromatic polymer molecule comprises a polyaniline polymer.

[0150] Implementation Scheme 29. The method according to Implementation Scheme 13, wherein the basic aromatic polymer molecule comprises a polybenzimidazole polymer.

[0151] Implementation Scheme 30. The method according to Implementation Scheme 13, wherein the basic aromatic polymer molecule is conductive.

[0152] Implementation Scheme 31. A membrane electrode assembly comprising: a first catalyst layer; a second catalyst layer; and a proton exchange membrane located between the first catalyst layer and the second catalyst layer; wherein at least one of the first catalyst layer, the second catalyst layer, and the proton exchange membrane is formed of a conjugated acid proton exchange polymer, the conjugated acid proton exchange polymer comprising: an acidic aromatic unit in the main chain or side chain, wherein the acidic aromatic unit is a conjugated acid of a basic aromatic unit; and a noncoordinate counter anion ionically bonded to the acidic aromatic unit.

[0153] Implementation Scheme 32. The membrane electrode assembly according to Implementation Scheme 31, wherein the conjugated acid proton exchange polymer is conductive; and at least one of the first catalyst layer or the second catalyst layer is formed of the conjugated acid proton exchange polymer.

[0154] Implementation Scheme 33. The membrane electrode assembly according to Implementation Scheme 32, wherein the proton exchange membrane is formed of a non-conductive additional conjugated acid proton exchange polymer.

[0155] Implementation Scheme 34. The membrane electrode assembly according to Implementation Scheme 31, wherein the conjugated acid proton exchange polymer comprises a polybenzimidazole onion polymer.

[0156] Implementation Scheme 35. The membrane electrode assembly according to Implementation Scheme 31, wherein the conjugated acid proton exchange polymer comprises a polyaniline polymer.

[0157] Implementation Scheme 36. A method for preparing a conjugated acid proton exchange polymer, the method comprising: crosslinking fluoroboronic acid functionalized polymer molecules with basic aromatic polymer molecules.

[0158] Implementation Scheme 37. The method according to Implementation Scheme 36, wherein the fluoroboronic acid functionalized polymer molecule comprises a polyfluorosulfonic acid polymer molecule having one or more sulfonic acid groups functionalized by fluoroboronic acid groups.

[0159] Implementation Scheme 38. The method according to Implementation Scheme 36, wherein the basic aromatic polymer molecule comprises a polybenzimidazole (PBI) polymer molecule.

[0160] Implementation Scheme 39. The method according to Implementation Scheme 36, wherein the basic aromatic polymer molecule comprises a polyaniline (PANI) polymer molecule.

[0161] Implementation Scheme 40. The method according to Implementation Scheme 36, wherein crosslinking the fluoroboronic acid functionalized polymer molecule with the basic aromatic polymer molecule comprises: subjecting the fluoroboronic acid group of the fluoroboronic acid functionalized polymer molecule to an acid-base reaction with the basic aromatic unit of the basic aromatic polymer molecule.

[0162] Implementation Scheme 41. A conjugate acid proton exchange polymer comprising: a first polymer molecule comprising an acidic aromatic unit, wherein the acidic aromatic unit is a conjugate acid of a basic aromatic unit; and a second polymer molecule comprising a trifluoroborate group, wherein the trifluoroborate group is a conjugate base of a fluoroborate group; wherein the first polymer molecule and the second polymer molecule are crosslinked by ionic bonding between the acidic aromatic unit and the trifluoroborate group.

[0163] Implementation Scheme 42. The conjugated acid proton exchange polymer according to Implementation Scheme 40, wherein the first polymer molecule comprises a polybenzimidazole (PBI) polymer.

[0164] Implementation Scheme 43. The conjugated acid proton exchange polymer according to Implementation Scheme 40, wherein the first polymer molecule comprises a polyaniline (PANI) polymer.

[0165] Implementation Scheme 44. The conjugated acid proton exchange polymer according to Implementation Scheme 40, wherein the second polymer molecule comprises a fluoroboronic acid functionalized sulfonic acid polymer.

Claims

1. A conjugate acid proton-exchanged polymer molecule comprising: an acidic aromatic unit in a backbone or side chain, wherein the acidic aromatic unit is a conjugate acid of a basic aromatic unit; and a non-coordinating counter-anion ionically bonded to the acidic aromatic unit.

2. The conjugate acid proton-exchanged polymer molecule of claim 1, wherein the non-coordinating counter-anion is a conjugate base of a strong acid.

3. The conjugate acid proton-exchanged polymer molecule of claim 1, wherein the non-coordinating counter-anion comprises tetrafluoroborate.

4. The conjugate acid proton-exchanged polymer molecule of claim 1, wherein the non-coordinating counter-anion comprises hexafluorophosphate.

5. The conjugate acid proton-exchanged polymer molecule of claim 1, wherein the non-coordinating counter-anion comprises hexafluoroantimonate.

6. The conjugate acid proton exchange polymer molecule of claim 1, wherein the non- coordinating counter-anion comprises a benzenesulfonate- triflate (PhSO3" ( ) ).

7. The conjugate acid proton- exchange polymer molecule of claim 1, wherein the non- coordinating counter-anion comprises a sulfate-di(triflate) ( ( ) ).

8. The conjugate acid proton-exchanged polymer molecule of claim 1, wherein the non-coordinating counter-anion comprises beryllium fluoride, aluminum fluoride, bismuth fluoride, antimony fluoride, phosphorus fluoride, tin fluoride, zirconium fluoride, or titanium fluoride.

9. The conjugate acid proton exchange polymer molecule of claim 1, wherein the non- coordinating counter-anion comprises a metal fluoroborate of the general formula [MF (n+1) ] where M is beryllium (Be), aluminum (Al), bismuth (Bi), antimony (Sb), phosphorus (P), tin (Sn), zirconium (Zr), or titanium (Ti), and n is the valence of M.

10. The conjugate acid proton-exchanged polymer molecule of claim 1, wherein the basic aromatic unit comprises aniline or an aniline derivative.

11. The conjugate acid proton-exchanged polymer molecule of claim 1, wherein the basic aromatic unit comprises an imidazole group or a benzimidazole group.

12. The conjugate acid proton-exchanged polymer molecule of claim 1, wherein the conjugate acid proton-exchanged polymer molecule is electrically conductive.

13. A method of making a conjugate acid proton-exchanged polymer molecule comprising: protonating a basic aromatic unit of a basic aromatic polymer molecule to form an acidic aromatic unit, wherein the acidic aromatic unit is a conjugate acid of the basic aromatic unit; and ionically bonding a non-coordinating counter-anion to the acidic aromatic unit.

14. The method of claim 13, wherein protonating the basic aromatic unit and ionically bonding the non-coordinating counter-anion to the acidic aromatic unit comprises acid-base reacting the basic aromatic unit with an acid, wherein a conjugate base of the acid comprises the non-coordinating counter-anion.

15. The method of claim 14, wherein the acid comprises fluoroboric acid.

16. The method of claim 14, wherein the acid comprises hexafluorophosphoric acid.

17. The method of claim 14, wherein the acid comprises fluorantimonic acid.

18. The method of claim 14, wherein the acid comprises a sulfuric acid-boron trifluoride complex having the general structure: 。 19. The method of claim 14, wherein the acid comprises a benzenesulfonic acid-boron trifluoride complex having the general structure: 。 20. The method of claim 14, wherein the acid comprises a benzenedisulfonic acid-boron trifluoride complex having the general structure: 。 21. The method of claim 14, wherein the acid comprises a phenyl trifluoroboric acid having the general structure: ， or a phenyl 1,4-di(trifluoro)boric acid having the general structure: 。 22. The method of claim 14, wherein the acid comprises a phosphoric acid- boron trifluoride complex having the general structure: 。 23. The method of claim 13, wherein: protonating the basic aromatic unit comprises acid-base reaction of the basic aromatic unit with hydrofluoric acid, wherein the conjugate base of the hydrofluoric acid comprises a fluoride counteranion ionically bonded to the acidic aromatic unit; and ionically bonding the non-coordinating counteranion to the acidic aromatic unit comprises reaction of the fluoride counteranion with boron trifluoride.

24. The method of claim 13, wherein: protonating the basic aromatic unit comprises acid-base reaction of the basic aromatic unit with hydrofluoric acid, wherein the conjugate base of the hydrofluoric acid comprises a fluoride counteranion ionically bonded to the acidic aromatic unit; and Bonding the non-coordinating counteranion to the acidic aromatic unit ion comprises reacting the fluoride counteranion with a metal fluoride of the general formula MF n where M is beryllium (Be), aluminum (Al), bismuth (Bi), antimony (Sb), phosphorus (P), tin (Sn), zirconium (Zr), or titanium (Ti), and n is the valence of M.

25. The method of claim 13, wherein: protonating the basic aromatic unit comprises acid-base reaction of the basic aromatic unit with an acid, wherein the conjugate base of the acid comprises a coordinating counteranion ionically bonded to the acidic aromatic unit; and ionically bonding the non-coordinating counteranion to the acidic aromatic unit comprises anion exchange reaction to exchange the coordinating counteranion for the non- coordinating counteranion.

26. The method of claim 25, wherein the acid has the general formula HA, wherein A is F, CI, Br, H 、 、 、 、 or a polyphosphate anion.

27. The method of claim 25, wherein the anion exchange reaction comprises making the general formula [formula missing]. The tetrafluoroborate metal compound reacts, where M is a sodium ion ( ), potassium ions ( ), cesium ions ( ), ammonium ( ) or general formula is Tetraalkylammonium, wherein each R is independently hydrogen, or a fully substituted, partially substituted, or unsubstituted alkyl group.

28. The method of claim 13, wherein the basic aromatic polymer molecule comprises a polyaniline polymer.

29. The method of claim 13, wherein the basic aromatic polymer molecule comprises a polybenzimidazole polymer.

30. The method of claim 13, wherein the basic aromatic polymer molecule is electrically conductive.

31. A membrane electrode assembly comprising: a first catalyst layer; a second catalyst layer; and a proton exchange membrane positioned between the first catalyst layer and the second catalyst layer; wherein at least one of the first catalyst layer, the second catalyst layer, and the proton exchange membrane is formed from a conjugate acid proton exchange polymer comprising: acidic aromatic units in a main chain or side chain, wherein the acidic aromatic units are conjugate acids of basic aromatic units; and non-coordinating counteranions ionically bonded to the acidic aromatic units.

32. The membrane electrode assembly of claim 31, wherein: the conjugate acid proton exchange polymer is electrically conductive; and at least one of the first catalyst layer or the second catalyst layer is formed from the conjugate acid proton exchange polymer.

33. The membrane electrode assembly of claim 32, wherein the proton exchange membrane is formed from an additional conjugate acid proton exchange polymer that is not electrically conductive.

34. The membrane electrode assembly of claim 31, wherein the conjugate acid proton exchange polymer comprises a polybenzimidazolium polymer.

35. The membrane electrode assembly of claim 31, wherein the conjugate acid proton exchange polymer comprises a polyaniline polymer.

36. A method of making a conjugate acid proton exchange polymer, the method comprising: crosslinking a fluoroboric acid-functionalized polymer molecule with a basic aromatic polymer molecule.

37. The method of claim 36, wherein the fluoroboric acid-functionalized polymer molecules comprise polyfluorosulfonic acid polymer molecules having one or more sulfonic acid groups functionalized with fluoroboric acid groups.

38. The method of claim 36, wherein the basic aromatic polymer molecules comprise polybenzimidazole (PBI) polymer molecules.

39. The method of claim 36, wherein the basic aromatic polymer molecules comprise polyaniline (PANI) polymer molecules.

40. The method of claim 36, wherein crosslinking the fluoroboric acid- functionalized polymer molecules with the basic aromatic polymer molecules comprises: allowing the fluoroboric acid groups of the fluoroboric acid-functionalized polymer molecules to undergo an acid-base reaction with the basic aromatic units of the basic aromatic polymer molecules.

41. A conjugate acid proton-exchange polymer comprising: a first polymer molecule comprising an acidic aromatic unit, wherein the acidic aromatic unit is a conjugate acid of a basic aromatic unit; and a second polymer molecule comprising a triflate group, wherein the triflate group is a conjugate base of a fluoroboric acid group; wherein the first polymer molecule and the second polymer molecule are crosslinked through ionic bonding between the acidic aromatic unit and the triflate group.

42. The conjugate acid proton-exchange polymer of claim 40, wherein the first polymer molecule comprises a polybenzimidazole (PBI) polymer.

43. The conjugate acid proton-exchange polymer of claim 40, wherein the first polymer molecule comprises a polyaniline (PANI) polymer.

44. The conjugate acid proton-exchange polymer of claim 40, wherein the second polymer molecule comprises a fluoroboric acid-functionalized sulfonic acid polymer.

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