Conjugated acid type proton exchange polymer, method for producing the same, and method for using the same

Abstract

A conjugated acid type proton exchange polymer molecule has an acidic aromatic unit in its main chain or side chain, the acidic aromatic unit being a conjugate acid of a basic aromatic unit, and containing a non-coordinating counteranion ionically bonded to the acidic aromatic unit.

Description

[Technical Field]

[0001] [Cross-reference of related applications] This application claims priority under U.S. Provisional Patent Application No. 63 / 457,873, filed on April 7, 2023, the contents of which are incorporated herein by reference in their entirety. [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 PEM is a semipermeable membrane that transports protons while being impermeable to gases. PEMs generally consist of a porous skeletal structure and functional groups with high acidity. For example, polyfluorosulfonic acid-based PEMs such as Nafion (trademark) (Chemours Company, Wilmington, Delaware) and Aquivion (registered trademark) (Solvay SA, Brussels, Belgium) contain a poly(tetrafluoroethylene) (PTFE) porous structure with sulfonic acid side chains. These easily dissociable sulfonic acid groups function as proton transporters in the membrane. In a hydrogen fuel cell, hydrogen gas (H2) transports protons (H2) at the anode. + The water is separated into protons (H) and electrons. The protons pass through the PEM and combine with oxygen gas (O2) at the cathode to produce water, while the electrons pass through an external circuit to generate electricity. In a water electrolysis system, electricity causes water to combine with oxygen gas (O2) and protons (H) at the anode. + It is decomposed into ), and the proton passes through the PEM and combines with electrons on the cathode side to produce hydrogen gas (H2).

[0003] A membrane electrode assembly (MEA) may include a PEM (Patent Electrode) positioned between a first catalyst layer and a second catalyst layer. These catalyst layers are electrically conductive electrodes (anode and cathode) on which an electrochemical catalyst, such as a metal, metal alloy, or metal oxide, is embedded. The catalyst is generally supported on a catalyst solid carrier made of electrically conductive, high-surface-area carbon (e.g., graphite or graphene). The electrochemical catalyst reduces the activation energy required to carry out electrochemical reactions at the electrodes, such as oxygen evolution (OER) and hydrogen evolution (HER) reactions in water electrolysis, and hydrogen oxidation (HOR) and oxygen reduction (ORR) reactions in fuel cells.

[0004] In one application, the catalyst layer comprises a mixture of a supported catalyst and an ionomer (ion-conducting polymer). The ionomer acts as a binder for the catalyst within the electrode and improves cation conductivity by assisting in the binding of the catalyst layer to the PEM and providing a transport pathway for cations (e.g., protons). In some MEAs, the catalyst layer is formed separately from the PEM and stacked on top of the PEM within the MEA stack. In other MEAs, the catalyst layer is coated onto the PEM to form a catalyst coating film (CCM).

[0005] In water electrolysis and fuel cell applications, strong oxidation and reduction reactions occur under acidic conditions ranging from room temperature to high temperatures. Therefore, PEMs and ionomers, as well as the molecular functional groups contributing to their proton transport properties, must be stable even under severe reaction conditions of redox stress. However, conventional polymers used as PEMs and ionomers, such as Nafion® and Aquivion®, primarily contain sulfonic acid functional groups as proton transporters. Due to the inherent physicochemical properties of sulfur, sulfonic acid functional groups have limited resistance to redox stress associated with electrochemical activity. Furthermore, sulfonic acid groups participate in secondary redox reactions, promoting poisoning of platinum group metal catalysts and depolymerization of the polymer matrix. [Overview of the project]

[0006] The accompanying drawings illustrate various embodiments of the present disclosure and constitute part of this specification. The illustrated embodiments are illustrative and do not limit the scope of the present disclosure. Throughout the drawings, the same or similar reference numerals indicate the same or similar elements. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows an example of a reaction pathway for producing a proton-conducting polybenzimidazolium (PBI+) polymer ionically bonded to a tetrafluoroboric acid counter anion. [Figure 2] This figure shows an example of another reaction pathway for producing a PBI+ polymer ionically bonded to a non-coordinating tetrafluoroboric acid counter anion. [Figure 3] This figure shows an example of a reaction pathway for producing a PBI+ polymer ionically bonded to one of several different non-coordinating metal fluoride vs. anions. [Figure 4] This figure shows an example of another reaction pathway for producing a PBI+ polymer ionically bonded to a non-coordinating tetrafluoroboric acid counter anion. [Figure 5] This figure shows an example of a proton exchange membrane water electrolysis system comprising a proton exchange membrane (PEM) and / or ionomer made of a conjugated acid type proton exchange polymer. [Figure 6] This figure shows an example of a proton exchange membrane fuel cell containing a proton exchange membrane (PEM) and / or ionomer made of a conjugated acid type proton exchange polymer. [Modes for carrying out the invention]

[0008] This specification describes conjugate acid type proton exchange polymers obtained by functional modification (post-polymerization functionalization) of basic aromatic polymers, as well as their manufacturing methods and uses. Basic aromatic polymers contain basic aromatic units (e.g., aryl groups and / or heteroaryl groups) in the main chain and / or side chains or side groups. Examples of basic aromatic polymers, but not limited to, include polybenzimidazole (PBI) polymers and polyaniline (PANI) polymers. 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 conjugate acid of the basic aromatic unit. In some examples, the counteranion (conjugate base) is the conjugate base of a strong acid, but the ion exchange group may be changed depending on the application and desired properties. Acidic aromatic units readily dissociate in an aqueous environment and hydrate to form a proton (H3O + It forms an equilibrium mixture containing ). Therefore, readily dissociable acidic aromatic units can function as proton transporters.

[0009] The conjugated acid proton exchange polymers described herein can be used in electrochemical cell applications such as PEMs, ionomers, catalyst layers, and membrane electrode assemblies (MEAs), and may also be used in other applications. The counteranions (conjugate bases) are non-coordinating anions, stable and inert even under harsh electrochemical reaction conditions, do not react with metal catalysts to poison them, and do not participate in secondary depolymerization reactions. Therefore, ionomers and PEMs based on the conjugated acid proton exchange polymers described herein reduce or eliminate catalyst poisoning compared to conventional ionomers and polymers containing sulfonic acid-functionalized polymers such as Nafion®.

[0010] The following definitions are provided to aid in understanding each aspect of this disclosure. When any term or expression such as alkyl, m, n, etc., is used more than once in this specification, they shall be interpreted independently of their definitions elsewhere in this specification. In the event of any conflict with the content of any patent application or patent incorporated herein by reference, the provisions of this specification, including their definitions, shall prevail.

[0011] In this specification, "polymer" means a substance consisting of polymer molecules of the same or different polymer species, and includes mixtures of molecules of the same polymer species in which the chain length and / or specific structural arrangement (e.g., irregularity of monomer unit orientation, terminal groups, and / or irregularity of the position and / or length of side chains or side groups) may differ from one another within the same sample. "Polymer" includes homopolymers, copolymers, telpolymers, interpolymers, and the like.

[0012] In this specification, "polymer molecule" or "macromolecule" means a molecule having a relatively high relative molecular weight and whose structure is composed of repeats of a large number of units (e.g., about 100 or more monomer units) that are (actually or conceptually) derived from molecules with a low relative molecular weight (e.g., monomer molecules).

[0013] In this specification, "polymerization" refers to the process of converting a monomer or a mixture of monomers into a polymer.

[0014] In this specification, "oligomer" means a substance composed of oligomer molecules.

[0015] In this specification, "oligomer molecule" means a molecule having a moderate relative molecular weight and whose structure is composed of a relatively small number (e.g., about 5 to about 100) repeating units derived (actually or conceptually) from molecules with a relatively low relative molecular weight (e.g., monomer molecules).

[0016] In this specification, "oligomerization" refers to the process of converting a monomer or a mixture of monomers into an oligomer.

[0017] The principles, concepts, and characteristics described herein with respect to polymers, polymer molecules, and polymerization are equally applicable to oligomers, oligomeric molecules, and oligomerization, respectively. Therefore, any use of “polymer,” “polymer molecule,” or “polymerization” herein may be substituted with “oligomer,” “oligomeric molecule,” or “oligomerization” without departing from the scope of this disclosure.

[0018] In this specification, "ionomer" refers to a polymer composed of ionomer molecules.

[0019] In this specification, "ionomer molecule" means a polymer molecule having a small but relatively significant proportion of its constituent units that are ionizable or ionic side chain groups (including ion exchange groups as described herein), or both. Generally, the constituent units having ionizable or ionic side chain groups are about 15 mol% or less.

[0020] In this specification, "monomer" means a substance consisting of monomer molecules.

[0021] In this specification, "monomer molecule" means a molecule that can form a polymer molecule or oligomer molecule by polymerization or oligomerization. Monomer molecules provide the basic structural units that make up polymer molecules or oligomer molecules.

[0022] In this specification, "copolymer" refers to a polymer derived from multiple types of monomers.

[0023] In this specification, "constitutional unit" means an atom or group of atoms (including any side chain groups) that constitutes part of the structure of a polymer molecule (or oligomer molecule, block, or chain).

[0024] In this specification, "repeating unit" refers to a constituent unit that, through its repetition, constitutes a polymer molecule (or oligomer molecule, block, or chain).

[0025] In this specification, "monomer unit" refers to a constituent unit that is provided as the largest unit in the structure of a polymer molecule or oligomer molecule by a single monomer molecule.

[0026] In this specification, "block" means a part of a polymer molecule (or oligomer molecule) that is composed of a number of constituent units and has at least one characteristic that is not present in adjacent parts.

[0027] In this specification, “chain” means a sequence of linear or branched structural units located between two boundary structural units (each which may be a terminal group, a branch point, or other defined feature of the polymer molecule), in whole or in part, of a polymer molecule (or oligomer molecule or block).

[0028] In this specification, "main chain" or "backbone" refers to a chain of polymer molecules that can be considered to have all other chains (whether long or short) suspended as side chains.

[0029] In this specification, "side chain" refers to an oligomeric (short chain) or polymeric (long chain) branch that branches off from the main chain of a polymer molecule.

[0030] In this specification, "side group" or "pendant group" refers to a branch that is neither oligomeric nor polymeric, branching from a chain (e.g., the main chain).

[0031] The principles, concepts, and features described herein with respect to side chains also apply to side groups. Therefore, any use of “side chain” herein, even if substituted with “side group,” does not deviate from the scope of this disclosure.

[0032] In this specification, "crosslink" refers to a small region within a polymer molecule in which at least four chains radiate outwards. Crosslinks are generally formed by reactions involving existing sites or groups on the polymer molecule, or by interactions between existing polymer molecules.

[0033] "Crosslinked" refers to a state in which polymer molecules, which were originally separate entities, are bonded to each other at points other than their ends.

[0034] In this specification, “catalyst particle” means a particle in black or pure form (excluding catalyst supports and catalyst additives on which the catalyst particle may be supported) that increases the reaction rate without altering the standard Gibbs free energy change in the reaction. Catalyst particles may be single molecules (not limited to monomer molecules), molecular aggregates, crystalline structures (e.g., metal oxides), polymer molecules, or oligomer molecules. The size and shape of the catalyst particles are arbitrary and may be, for example, microparticles, nanoparticles, nanotubes, etc. Catalyst particles may include, for example, metals, metal alloys, metal oxides, metal halides (e.g., metal chlorides), or composites containing at least one of these.

[0035] In this specification, "electrocatalyst particle" refers to a catalyst particle that reduces the activation energy required to carry out an electrochemical reaction and / or increases the rate of an electrochemical reaction. Suitable electrochemical catalyst particles include, but are not limited to, platinum group metals (PGMs) (e.g., platinum, palladium, iridium, ruthenium, osmium, rhodium), transition metals (e.g., silver, gold, cobalt, copper, iron, nickel, rhenium, mercury), post-transition metals (e.g., bismuth, tin), metal alloys (e.g., PGM-transition metal alloys, platinum-ruthenium alloys), metal oxides (e.g., iridium dioxide, ruthenium dioxide, iridium-ruthenium oxide, platinum tetroxide, magnesium oxide, cerium dioxide as PGM oxides), metal halides (e.g., platinum tetrachloride, iridium trichloride, platinum tetrabromide, iridium tribromide), and / or composites of these metals, metal alloys, metal oxides, and metal halides.

[0036] In this specification, “catalyst support” means a substance other than catalyst particles that can be used to support catalyst particles (e.g., a substance or material to which catalyst particles can be bound / supported). Examples of catalyst supports include, but are not limited to, carbon-based materials (e.g., carbon black, graphite, carbon nanotubes, graphene, and the boron-functionalized carbon materials described herein), titanium dioxide, Sb-doped SnO2 nanoparticles, ITO (indium tin oxide), and the ion-exchange modified catalyst support described in International Application No. PCT / US2022 / 046105 (filed October 7, 2022), the contents of which are incorporated herein by reference in their entirety.

[0037] In this specification, "catalyst" means a catalyst comprising catalyst particles and a catalyst support on which the catalyst particles are supported or bound. The catalyst may also include catalyst additives such as promoters (for example, containing but not limited to light elements).

[0038] In this specification, "electrocatalyst" refers to a catalyst comprising black-form electrocatalyst particles, as well as a catalyst support on which the electrocatalyst particles are supported or bound. The electrocatalyst may also include catalyst additives such as promoters.

[0039] In this specification, "metal" includes alkali metals, alkaline earth metals, transition metals, lanthanides, actinides, and post-transition metals.

[0040] In this specification, "transition metals" refers to the elements in block d (groups 3 to 12) of the periodic table.

[0041] In this specification, "post-transition metals" refers to aluminum, gallium, indium, tin, thallium, lead, bismuth, and polonium.

[0042] In this specification, "metalloids" refers to boron, silicon, germanium, arsenic, antimony, tellurium, and astatine.

[0043] In this specification, "platinum group metals (PGM)" refers to platinum, palladium, iridium, ruthenium, osmium, and rhodium.

[0044] In this specification, "aliphatic" compounds mean saturated or unsaturated, acyclic or cyclic, linear or branched, unsubstituted or partially substituted with one or more substituents or functional groups. As will be understood by those skilled in the art, "aliphatic" in this specification includes, but is not limited to, alkyl, alkenyl, and alkynyl substructures. Representative aliphatic groups include, for example, 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.

[0045] In this specification, “alkyl (alkyl)” has the common meaning in the industry and may include linear alkyl, branched alkyl, cycloalkyl (alicyclic), alkyl-substituted cycloalkyl, and cycloalkyl-substituted alkyl. Similar practice applies to other common names (e.g., “alkenyl,” “alkynyl,” etc.). Furthermore, in this specification, terms such as “alkyl,” “alkenyl,” and “alkynyl” include both unsubstituted groups and groups that are fully or partially substituted.

[0046] In some embodiments, linear or branched alkyl chains have 1 to 30 carbon atoms in their skeleton, and optionally 1 to 20 or fewer. In some embodiments, linear or branched alkyl chains have 1 to 10 carbon atoms in their skeleton (e.g., C1 to C10 for linear chains, C3 to C10 for branched chains), and optionally 6 or fewer, or 4 or fewer. Cycloalkyls may have 3 to 10 carbon atoms in their ring structure, and optionally 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.

[0047] The terms "alkenyl" and "alkynyl" refer to unsaturated aliphatic groups that are similar in chain length and substitutability to the alkyl groups described above, and each contains at least one double or triple bond. Examples of alkenyl groups, but not limited to, include ethenyl, propenyl, butenyl, and 1-methyl-2-buten-1-yl. Examples of non-limited alkynyl groups include ethynyl, 2-propynyl (propargyl), and 1-propynyl.

[0048] A "heteroatom" refers to any atom other than carbon. Non-restrictive examples of heteroatoms include B, N, O, Al, Si, P, S, Ge, As, Se, and Sb. In some examples, the heteroatom is selected from B, N, O, P, and S.

[0049] A "heteroalkyl group" refers to an alkyl group in which one or more hydrogen atoms bonded to any carbon atom of the alkyl group, or one or more carbon atoms, are substituted with heteroatoms. Examples of heteroalkyl groups, though not limited to them, include methoxy, ethoxy, propoxy, isopropoxy, methylthio, ethylthio, propylthio, isopropylthio, n-butylthio, methoxymethyl, and cyano groups.

[0050] The terms "heteroalkenyl" and "heteroalkynyl" refer to unsaturated aliphatic groups that are similar in chain length and substitutionability to the heteroalkyl groups described above, and each contains at least one double or triple bond.

[0051] "Aryl" refers to an aromatic carbocyclic group having a monocyclic (e.g., phenyl), polycyclic (e.g., biphenyl), or fused polycyclic ring, with or without substitution, in which at least one ring of the aryl group is aromatic (e.g., 1,2,3,4-tetrahydronaphthyl, naphthyl, anthryl, phenanthryl). That is, at least one ring of the aryl group has a conjugated π-electron system, and the other rings can be cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, and / or heterocyclic. "Carbocyclic aryl group" refers to an aryl group in which the ring atom of the aromatic ring is a carbon atom. Carbocyclic aryl groups include monocyclic and polycyclic or fused cyclic compounds (e.g., naphthyl) that share two or more adjacent ring atoms. The aryl group is not limited to benzene and its derivatives, and the number of ring atoms can be arbitrary. Examples of aryl groups, though not limited to them, include phenyl, naphthyl, tetrahydronaphthyl, anilyl, indanyl, and indenyl.

[0052] A "heteroaryl" refers to an aryl group that contains at least one heteroatom (e.g., a heteroaromatic group) as a ring atom, i.e., a heterocyclic group. Non-limiting examples of heteroaryl groups include pyridyl, pyrazinyl, pyrimidinyl, pyrrolyl, pyrazolyl, imidazolyl, thiazolyl, oxazolyl, isoxazolyl, thiadiazolyl, oxadiazolyl, thienyl, furyl, quinolinyl, and isoquinolinyl. Heteroaryl groups may also be referred to as A-heteroaryl using the heteroatom element symbol A. For example, N-heteroaryl refers to an aryl group that contains at least one nitrogen atom as a ring atom.

[0053] In this specification, "alkoxy" refers to an alkyl group bonded via an oxygen atom, and is represented by the general formula RO. Examples of alkoxy groups, but not limited to, include methoxy, ethoxy, propoxy, and tert-butoxy.

[0054] "Aryloxy" refers to an aryl group bonded through an oxygen atom. Examples of aryloxy groups include, but are not limited to, the phenoxy group.

[0055] Any of the above groups may optionally be wholly or partly substituted. Examples of substituents include, but are not limited to, aliphatic, alicyclic, heteroaliphatic, heteroalicyclic, halogen, azide, alkyl, aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxyl, alkoxy, amino, amine, nitro, sulfhydryl, imino, amide, phosphonate, phosphinate, carbonyl, carboxyl, alkoxycarbonyl, silyl, ether, alkylthio, heteroalkylthio, heteroarylthio, sulfonyl, sulfonamide, ketone, aldehyde, ester, heterocyclic, aromatic or heteroaromatic moieties, -CF3, -CN, aryl, aryloxy, perhaloalkoxy, aralkoxy, heteroaryl, heteroaryloxy, heteroarylalkyl, heteroaralkoxy, azide, amino, halide, alkylthio, oxo, acylalkyl, carboxyester, -carboxamide, acyloxy, aminoalkyl, alkylaminoaryl, alkylaryl, alkylaminoalkyl, alkoxyaryl, arylamino, aralkylamino, alkylsulfonyl, -carboxamidealkylaryl, -carboxamidearyl, hydroxyalkyl, haloalkyl, alkoxyalkyl, perhaloalkyl, arylalkyloxyalkyl, (e.g., SO4(R’)2), phosphate groups (e.g., PO4(R’)3), silanes (e.g., Si(R’)4), urethanes (e.g., R’O(CO)NHR’) and the like. Further, substituents include F, Cl, Br, I, -OH, -NO2, -CN, -NCO, -CF3, -CH2CF3, -CHCl2, -CH2OR x , -CH2CH2OR x , -CH2N(R x )2, -CH2SO2CH3, -C(O)R x , -O2(R x ), -CON(R x )2, -OC(O)R x-C(O)OC(O)R x , -OCO2R x ,-OCON(R x )2, -N(R x )2, -S(O)2R x , -OCO2R x , -NR x (CO)R x , -NR x (CO)N(R x )2 may be selected, and here each R x Each of these independently includes, but is not limited to, hydrogen, aliphatic, alicyclic, heteroaliphatic, heteroalicyclic, aryl, heteroaryl, alkylaryl, or alkylheteroaryl. These aliphatic, alicyclic, heteroaliphatic, heteroalicyclic, alkylaryl, and alkylheteroaryl substituents may be substituted or unsubstituted, branched or unbranched, or cyclic or acyclic, and similarly, the aryl or heteroaryl substituents may be substituted or unsubstituted.

[0056] Polytetrafluoroethylene (PTFE) polymers are a group of polymers and their derivatives composed of tetrafluoroethylene polymer molecules produced by the polymerization of tetrafluoroethylene. PTFE polymer molecules have a carbon main chain in which two fluorine atoms are bonded to each carbon atom, and this group includes its derivatives.

[0057] Polychlorotrifluoroethylene (PCTFE) polymers are derivatives of PTFE and homopolymers of chlorotrifluoroethylene (CTFE) (CF2CClF). nPCTFE has the molecular formula and includes its derivatives. PCTFE is similar to PTFE (Teflon, etc.), but differs in that each repeating unit contains one chlorine atom. The presence of this chlorine atom gives PCTFE unique properties as a versatile thermoplastic polymer. However, PCTFE has a hydrophobic main chain and does not exhibit ionic conductivity, so it is not suitable for electrochemical applications. Derivatives of PCTFE polymers include those that have substituents (e.g., side chains or side groups) instead of chlorine atoms. Derivatives of PCTFE may be substituted in whole or in part. Derivatives of PCTFE polymers include modified PCTFE and functionalized PCTFE (e.g., acid-functionalized and ion-exchange-functionalized PCTFE), which are described in U.S. Provisional Application No. 63 / 532,262 (filed August 11, 2023), the contents of which are incorporated herein by reference.

[0058] Sulfonic acid-functionalized PTFE polymers are derivatives of PTFE polymers, comprising a PTFE main chain and side chains or side groups having one or more sulfonic acid groups as pendant groups. In some examples, the side chain is a long side chain (LSC) having at least two ether bonds and four or more polyfluorinated carbon units (e.g., -CF2- and / or -CF3). In other examples, the side chain is a short side chain (SSC) having one ether bond and two polyfluorinated carbon units. In yet another example, the side chain is a mid-side chain (MSC) having one ether bond and four polyfluorinated carbon units. In some examples, sulfonic acid-functionalized PTFE polymers have the general formula [(CF2CF2) m (CFACF2) n ] xRepresented as , where A is a side chain containing one or more pendant sulfonic acid groups, and m, n, and x are positive numbers selected based on application, equivalent weight, molecular weight, etc. In some examples, m is 4-7 and n is 1. In some examples, side chain A is LSC, MSC, or SSC. Examples of LSC sulfonic acid-functionalized PTFE include, but are not limited to, the Nafion® series (various specifications including Chemors, Nafion®-H, Nafion®HP, Nafion®117, Nafion®115, Nafion®212, Nafion®211, Nafion®NE1035, Nafion®XL, etc.), and any combination, derivatives, grades, and forms thereof. Examples of SSC sulfonic acid-functionalized PTFE include, but are not limited to, the Aquivion® series (Solvay Sa, Aquivion® E98-05, Aquivion® PW98, Aquivion® PW87S, etc.), Gore-Select® (WL Gore & Associates), Flemion® (Asahi Glass), Pemion+® (Ionomr Innovations), etc., and include any combination, derivatives, grades, and forms thereof. Examples of MSC sulfonic acid-functionalized PTFE include, but are not limited to, polymers manufactured by 3M®. In some examples, the PTFE polymer may be a copolymer containing one or more other repeating units. In some examples, the PTFE polymer may be doped and / or crosslinked with itself or with other polymers.

[0059] Sulfonic acid-functionalized polymers include, but are not limited to, polyfluorosulfonic acid (PFSA) polymers and non-fluorinated sulfonic acid polymers. Examples of PFSAs include, but are not limited to, sulfonic acid-functionalized PTFE polymers and sulfonic acid-functionalized PCTFE polymers. Examples of non-fluorinated sulfonic acid polymers include, but are not limited to, poly(styrene sulfonic acid), sulfonated aromatic polymers (e.g., sulfonated poly(ether ketone) (SPEEK), sulfonated poly(aryl ether sulfone) (SPAES), sulfonated poly(arylene ether ketone) (SPAEK), sulfonated polysulfone (SPSF), sulfonated polyimide (SPI), sulfonated polystyrene (SPS), sulfonated polyphenylene), and sulfonated derivatives of the polymers described herein.

[0060] Polystyrene polymers are polymers composed of polystyrene polymer molecules. Polystyrene polymer molecules have repeating units in which carbon centers bonded to phenyl groups are arranged alternately. Examples of polystyrene polymers, though not limited to them, include polystyrene, poly(styrenesulfonic acid) (e.g., poly(4-styrenesulfonic acid)), polyhalostyrene, poly(3-trifluoromethylstyrene), poly(4-acetoxystyrene), poly(4-allylstyrene), poly(4-cyanostyrene), poly(4-dimethylsilylstyrene), poly(4-hydroxystyrene), poly(α-methylstyrene), poly(4-methylstyrene), poly(4-methoxystyrene), poly(4-[tert-butoxycarbonyl]oxystyrene), poly(4-tert-butylstyrene), poly(4-[N,N-di(trimethylsilyl)aminomethyl]styrene), poly(4-vinylbenzoic acid), poly(n-butyl 4-vinylbenzoate ester), poly(tert-butyl 4-vinylbenzoate ester), poly(2-ethylhexyl 4-vinylbenzoate ester), and poly(methyl Examples include poly(vinylbenzyl chloride), poly(4-vinylbenzyl-N-methylphthalimide), poly(vinylcyclohexane), and their derivatives (including substituted (e.g., fluorinated) and / or branched) compounds. In some examples, the polystyrene polymer may be a copolymer comprising one or more additional repeating units, which may or may not contain a carbon center bonded to a phenyl group.

[0061] Aromatic polymers are polymers that have one or more aromatic units in their main chain and / or side chains. An aromatic unit contains one or more aryl groups and / or heteroaryl groups. Examples of aromatic polymers, though not limited to them, include polystyrene, polycarbonate, polyphenylene polymers (e.g., poly(1,4-phenylene), poly(1,4-phenylene-ethylene), poly(1,3-phenylene-methylene), poly(p-phenylenevinylidene), poly(p-phenylenevinylen), poly(1,4-phenylene oxide), poly(1,4-phenylene sulfide)), poly(ethersulfone), polyaryletherketone, polysulfone, poly(ethylene terephthalate), aromatic polyester, poly(oxy-1,4-phenylenecarbonyl-1,4-phenylene), poly[(dimethylmethylene)bis(4,1-phenylene)carbonate], phenolic resin, poly[(ethylazanediyl)ethyleneazanediyl-1,3-phenylene], poly-oxydiphenylene-pyromelliimide (Kapton®, EI du Examples include poly(esterimides), aromatic polyimides, lignins, and their derivatives (including substituted (e.g., fluorinated) and / or branched compounds), manufactured by Pont de Nemours and Company.

[0062] Conjugated acid proton exchange polymers are synthesized by acid-base reactions following polymerization of a basic aromatic polymer with an acid. A basic aromatic polymer refers to a polymer having basic aromatic units in its main chain and / or side chains. Basic aromatic units contain basic aryl groups and / or basic heteroaryl groups. The acid-base reaction protonates the basic aromatic units, converting them into acidic aromatic units. The acidic aromatic unit is the conjugate acid of the basic aromatic unit and has a positive formal charge upon protonation.

[0063] The resulting conjugated acid proton exchange polymer molecules have acidic aromatic units in their main chain or side chains, and counter anions ionically bonded to these acidic aromatic units. Conventional counter anions, such as sulfates (derived from sulfuric acid), phosphates (derived from phosphoric acid and polyphosphate), and halides, exhibit significant coordinating properties. These coordinating anions contribute to catalyst poisoning through reactions with metal catalysts and promote depolymerization reactions, reducing the processing capacity and lifetime of membrane electrode assemblies (MEAs). The size of the counter anion, more specifically its ionic potential (anion charge / anion radius ratio), also contributes to controlling the hydrogen bonding network and water retention of the proton exchange membrane.

[0064] To address these challenges, non-coordinating anions are used as counter-anions that ionically bond with acidic aromatic units. Non-coordinating counter-anions are stable and inert even under harsh electrochemical reaction conditions, do not react with metal catalysts to cause catalyst poisoning, and do not participate in secondary depolymerization reactions. Therefore, in some cases, the conjugate base of the acid reagent used in the acid-base reaction is a non-coordinating anion, resulting in a non-coordinating counter-anion that ionically bonds with the acidic aromatic unit. In other cases, if the conjugate base of the acid reagent is coordinating, a fluoride treatment step is performed after the acid-base reaction to convert the counter-anion to a non-coordinating counter-anion (e.g., tetrafluoroboric acid or a metal fluoride), or an anion exchange step is performed after the acid-base reaction to exchange the counter-anion for a non-coordinating counter-anion (e.g., tetrafluoroboric acid). Details of the fluoride treatment step and the anion exchange step will be described later.

[0065] As described above, basic aromatic units include a basic aryl group and / or a basic heteroaryl group. The basic aryl group and the basic heteroaryl group include an amine having a lone pair of electrons capable of accepting a proton from an acid, thereby making the aryl group or heteroaryl group, and by extension the aromatic unit, weakly basic. The amine may be present within the aromatic ring of the aromatic unit, as seen in the N-heteroaryl group, or as a substituent on the aromatic ring, as seen in aniline (e.g., allylamine). The amine may be primary, secondary, or tertiary. In this specification, a primary amine means a nitrogen atom bonded to one carbon atom and two hydrogen atoms (C-NH2), a secondary amine means a nitrogen atom bonded to two carbon atoms and one hydrogen atom (C-NH-C), and a tertiary amine means a nitrogen atom bonded to two carbon atoms and not to a hydrogen atom (CN=C) or to three carbon atoms (CN(-C)(-C)). Tertiary amines, which are basic aromatic units, are more strongly based than secondary amines, and secondary amines are more strongly based than primary amines.

[0066] Non-limiting examples of basic aromatic units include anilines (e.g., aniline, toluidine, xylidine, chloroaniline, aminobenzoic acid, nitroaniline, 2,5-diamino-1,4-phenylene) and pyridines (e.g., 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) ), pyrazines (e.g., alkylpyrazines such as 2,3-dimethylpyrazine, 2,5-dimethylpyrazine, 2,3,5-trimethylpyrazine, 2,6-dimethylpyrazine, and 2-ethyl-3-methylpyrazine, and methoxylated pyrazines such as 3-isobutyl-2-methoxypyrazine), imidazoles (e.g., 1,5-dihydrobenzo[1,2-d;4,5-d']diimidazole-2,6-diyl; 4-phenyl-1H-imidazole-2,5-diyl; 4-phenyl-1H-imidazole-5,2-diyl; 5-phenyl-1H-imidazole (-4,2-diyl), pyrazoles (e.g., 1H-pyrazole, 3H-pyrazole, 4H-pyrazole, aminopyrazoles (3-aminopyrazole, 4-aminopyrazole, 5-aminopyrazole, etc.), diaminopyrazoles (e.g., 3,5-diaminopyrazole), 1-(1-adamantyl)pyrazole, 1,4-di(1-adamantyl)pyrazole, aminopyrine (aminophenazone), metamizole), pyrimidines (e.g., 2,4-dioxopyrimidine, 2,4-dioxo-5-methylpyrimidine, 2-oxo-4-aminopyrimidine) Midines, 2,4-dioxo-6-carboxypyrimidines, 5-bromo-2,4-dichloropyrimidines), pyridazines, thiazoles (e.g., [6,6'-bi(1,3-benzothiazole)]-2,2'-diyl, [2,2'-bi(1,3-thiazole)]-4,4'-diyl), imidazolines, quinolines (e.g., quinoline-2,4-diyl; [3,3'-biquinoline]-6,6'-diyl), isoquinolines, acridines, quinoxalines (e.g., 3,3'-diphenyl-[6,6'-biquinoxaline]-2,2'-diyl;Examples include 1H,1'H-[5,5'-bibenzimidazole]-2,2'-diyl), benzimidazoles, purines, indazoles, quinazolines, cinnolines, tetrazines (e.g., 1,2,4,5-tetrazine-3,6-diyl), thiophenes (e.g., 3,4-dioctylthiophene-2,5-diyl; thiophene-2,5-diyl; thiophene-2,4-diyl) and their derivatives.

[0067] Basic aromatic polymers include polymers produced by polymerization of monomer units containing basic aromatic units, or polymers based on or incorporating basic aromatic units in other forms. Non-limiting examples include polyaniline (PANI) (including lucoemeraldine, emeraldine, and pernigranilin forms), polypyrrole (PPy), polypyridine (e.g., poly(2-isopropenylpyridine), poly(2,5-pyridine), poly(3,5-pyridine), poly(2-vinylpyridine), poly(4-vinylpyridine)), polypyrazine (e.g., poly(2-vinylpyrazine)), polyimidazole (e.g., poly(N-vinylimidazole), Examples include poly(4-vinylimidazole)), polypyrazole, polypyrimidine, polypyridazine (PPd), polythiazole, polyimidazoline, polyquinoline, polyisoquinoline, polyacridine, polyquinoxaline, polybenzimidazole, polypurine, polyindazole, polyquinazoline, polysinnoline, polytetrazine, and polymers containing basic aromatic units in their side chains or side groups (e.g., poly(4-vinylpyridine) (PVP)).

[0068] The acid reagent donates a proton to a basic aromatic unit, generating a conjugate acid of that basic aromatic unit. The acid reagent used is not particularly limited. In some cases, the conjugate base of the acid reagent is non-coordinating, resulting in the formation of a counteranion that is stable and inert even under harsh electrochemical reaction conditions, does not react with metal catalysts to poison them, and does not participate in secondary depolymerization reactions. Non-limiting examples of suitable acids with non-coordinating conjugate bases include fluoroboric acid (HBF4) (tetrafluoroboric acid or hydrogen tetrafluoroboric acid ([H+ ][BF4 - Examples include phenyltrifluoroboric acid, 1,4-di(trifluoro)borophenylic acid, hexafluorophosphate (HPF6), fluoroantimonic acid (also known as hydrogen hexafluoroantimonate (HF6Sb)), sulfuric acid-boron trifluoride complex, benzenesulfonic acid-boron trifluoride complex, benzenedisulfonic acid-boron trifluoride complex, and phosphoric acid-boron trifluoride complex, each represented by the following general structural formula. [ka]

[0069] Furthermore, other acid reagents having one or more fluoroboric acid groups are also included in the scope of this disclosure and can be used as substitutes for the acid reagents described above. In some examples, the non-coordinating conjugate base / anion produced by the acid reagent is tetrafluoroboric acid ([BF4 - ]), phenyltrifluoroborate (PhBF3 - ), hexafluorophosphate ([PF6 - ]), hexafluoroantimonic acid ([SbF6 - ]), benzenesulfonate-trifluoroboric acid (PhSO3(BF3) - ), or sulfatose-di(trifluoroboric acid)(SO4(BF3)2 - )

[0070] In other examples, the conjugate base / counterion of the acid reagent is not non-coordinating. For example, sulfates, phosphates, and halides exhibit significant coordinating properties. As described below, coordinating counterions can be converted or exchanged to non-coordinating counteranions by fluoride treatment or anion exchange steps. In this case, the acid reagent may be an acid represented by the general formula HA (where A is a halide (e.g., F, Cl, Br), HSO4, SO4, H2PO4, HPO4, PO4, or a polyphosphate anion derived from any polyphosphate). Suitable examples of polyphosphates, but not limited to, include diphosphate, triphosphate, tetraphosphate, and trimetaphosphate. Examples of non-limited acid HA include hydrofluoric acid (HF), hydrochloric acid (HCl), hydrobromic acid (HBr), sulfuric acid (H2SO4), fluorophosphate (H2PO3F), phosphoric acid (H3PO4), or polyphosphate.

[0071] The degree of protonation of basic aromatic units can be adjusted to a desired level by adjusting the molar ratio of the acid reagent to the basic aromatic units of the polymer. For example, the molar ratio of the acid reagent to the basic aromatic units can be 1:1, 1:2, 1:3, or other appropriate molar ratios. In some cases, the acid reagent becomes the rate-limiting agent, and the aromatic units are not fully protonated. In yet other cases, the molar ratio of the acid reagent to the basic aromatic units exceeds 1:1 (e.g., 1.5:1, 2:1, 3:1, etc.), and the basic aromatic units are fully protonated.

[0072] In acid-base reactions, basic aromatic units are protonated by an acid and converted into acidic aromatic units. Acidic aromatic units are conjugate acids of basic aromatic units. Therefore, polymer molecules produced by acid-base reactions are called conjugate acid polymer molecules. This reaction can be carried out under standard conditions and does not require a catalyst. In the reaction, the amine of the basic aromatic unit is protonated by accepting a proton from the acid via its lone pair of electrons. 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) is called an imidazolium unit or a pyridinium unit, respectively. When the basic aromatic unit contains aniline (as in PANI), the acidic aromatic unit (N-protonated conjugate acid) is an ammonium derivative. Acidic aromatic units have a positive charge on the protonated nitrogen and are charge-neutralized by a counter-anion ionically bonded to the acidic aromatic unit. A counterion is the conjugate base of an acid reagent.

[0073] If the acid reagent is HBF4, HPF6, or fluoroantimonic acid, the counterion is a non-coordinating counteranion (tetrafluoroboric acid ([BF4 - ]), hexafluorophosphate ([PF6 - ]), hexafluoroantimonic acid ([SbF6 - Therefore, the conjugated acid type proton exchange polymer can be used in electrochemical applications.

[0074] In some cases, the ion exchange capacity (IEC) of conjugated acid proton exchange polymers can be increased by using acid reagents other than fluoroboric acid. In further cases, acid reagents having multiple fluoroboric acid groups (e.g., phenyltrifluoroboric acid, 1,4-di(trifluoro)borophenylic acid, sulfonic acid-BF3 complex, phosphoric acid-BF3 complex) also act as crosslinking agents, with each fluoroboric acid group reacting with different basic aromatic units of the same or different polymer molecules. Such crosslinking improves both the durability and IEC of the resulting conjugated acid proton exchange polymer.

[0075] If the conjugate base of the acid reagent is coordinating, the intermediate conjugate acid type proton exchange polymer is subjected to a fluoride treatment step or anion exchange step to convert or replace the counteranion with a non-coordinating counteranion.

[0076] For example, if the acid reagent is hydrofluoric acid (HF), then in the acid-base reaction, the counterion becomes a fluoride anion (F). - An intermediate conjugated acid type proton exchange polymer is produced. Next, (as a fluoride treatment step) the intermediate polymer is treated with boron trifluoride (e.g., boron trifluoride etherate (BF3·Et2O)), difluoro(phenyl)borane (any of the general structural formulas below) [ka] or general type MF n It is used in combination with metal fluorides represented by the formula [MF(n+1)] (where M is Be, Al, Bi, Sb, P, Sn, Zr, or Ti, and n corresponds to the valence of M). Boron trifluoride reacts with fluoride anions via addition to form a non-coordinating tetrafluoroborate counteranion (in this case, B increases its oxidation state and adds fluoride). Similarly, difluoro(phenyl)borane reacts with fluoride anions via addition to form a non-coordinating trifluoro(phenyl)borate counteranion. Metal fluorides react with fluoride anions via addition to form a compound of the general formula [MF(n+1)] -It forms a non-coordinating metal fluoride pair anion represented by (in this case, M increases its oxidation state and adds fluoride). Some examples of non-coordinating metal fluoride pair anions are beryllium fluoride (BF2), aluminum fluoride (AlF3), bismuth fluoride (e.g., bismuth trifluoride (bismuth(III) fluoride)), antimony fluoride (e.g., antimony(III) trifluoride), phosphorus fluoride (e.g., monofluorophosphate, difluorophosphate, hexafluorophosphate), tin fluoride (tin(II) fluoride (stannous fluoride)), zirconium fluoride (e.g., zirconium(IV) fluoride), and titanium fluoride (e.g., titanium trifluoride (titanium(III) fluoride), titanium tetrafluoride (titanium(IV) fluoride)).

[0077] In some cases, using difluoro(phenyl)borane in fluoride treatment increases the ion exchange capacity (IEC) of conjugated acid proton exchange polymers compared to using boron trifluoride. Furthermore, difluoro(phenyl)borane, which has two difluoroboryl groups, also acts as a crosslinking agent, with each difluoroboryl group crosslinking different aromatic units of the same or different polymer molecules. Such crosslinking improves the durability and IEC of the resulting conjugated acid proton exchange polymer.

[0078] In another example, if the acid reagent is an acid represented by the general formula HA mentioned above, the acid-base reaction will result in the acidic aromatic unit becoming the coordinating counteranion A. - An intermediate conjugated acid type proton exchange polymer is formed by ionic bonding with the intermediate. Then (as an anion exchange step), the intermediate polymer is converted into a metal tetrafluoroborate compound (general formula MBF4, where BF4 - is tetrafluoroborate anion, M is Na + , K + , Cs + NH4 + , or tetraalkylammonium (R4N +Each R is independently used in combination with hydrogen or a substituted or unsubstituted alkyl group having 1-20, 1-10, 1-8, 1-6, or 1-4 carbon atoms (including, but not limited to, methyl, ethyl, propyl, butyl, etc.). Metal M is the counter anion A - It combines with to form a salt of general formula MA, and tetrafluoroboric acid (BF4 - A is a counter anion that binds to an acidic aromatic unit. - This is substituted. As a result of the anion exchange process, a conjugated acid type proton exchange polymer is obtained that is ionically bonded to a non-coordinating tetrafluoroboric acid counter anion.

[0079] In some cases, conjugated acid proton exchange polymers possess electrical conductivity in addition to proton conductivity. In such cases, these polymers are obtained from electrically conductive polymers such as polyaniline or polypyrrole. In other cases, conjugated acid proton exchange polymers are electrically nonconductive, and in such cases, they are obtained from electrically nonconductive polymers.

[0080] The following describes a method for converting a weakly basic polymer into a proton-conducting conjugate acid polymer, using a weakly basic PBI polymer as an example. However, the principles described herein are also applicable to any other basic aromatic polymer.

[0081] PBI polymers are a group of polymers composed of PBI polymer molecules. PBI polymer molecules have repeating units containing benzimidazole units as at least part of their main chain. The benzimidazole units include the benzimidazole moiety or its derivatives. Benzimidazole is a heteroaromatic compound in which a phenyl ring and an imidazole ring share two carbon atoms within their respective ring structures. The general structural formula of benzimidazole is shown in formula (I) below. [ka]

[0082] Examples of PBI polymers having one benzimidazole unit per repeating unit of the main chain include poly(2,5-benzimidazole) (AB-PBI) (formula (II) below), and examples of PBI polymers having two benzimidazole units per repeating unit include poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole] (m-PBI) (formula (III) below) and its fluorinated derivative 4F-PBI (formula (IV) below). [ka]

[0083] Other examples of PBI polymers, but not limited to, include poly{2,6-(2,6-naphthylidene)-1,7-dihydrobenzo[1,2-d;4,5-d']diimidazole}, poly-2,2'-(2,6-naphthylidene)-5,5'-vibenzimidazole, poly-2,2'-(2,6-pyridine)-5,5'-vibenzimidazole, poly-2,2'-(2,5-pyridine)-5,5'-vibenzimidazole, and poly-2,2'-(2,2'-bipyridine-5,5')-5,5'- Bibenzimidazole, poly-2,2'-(3,5-pyrazole)-5,5'-vibenzimidazole, poly-2,2'-(m-phenylene)-5,5'-vibenzimidazole, poly-2,2'-(pyridylene-3'',5'')-5,5'-vibenzimidazole, poly-2,2'-(frylene-2'',5'')-5,5'-vibenzimidazole, poly-2,2'-(naphthalene-1'',6'')-5,5'-vibenzimidazole, poly-2,2'-(biphenylene-4'', 4'')-5,5'-vibenzimidazole, poly-2,2'-amylene-5,5'-vibenzimidazole, poly-2,2'-octamethylene-5,5'-vibenzimidazole, poly-2,6-(m-phenylene)-diimidazolebenzene, poly-2,2'-cyclohexenyl-5,5'-vibenzimidazole, poly-2,2'-(m-phenylene)-5,5'-di(benzimidazole)ether, poly-2,2'-(m-phenylene)-5,5'-di(benzimidazole) Examples include rufid, poly-2,2'-(m-phenylene)-5,5'-di(benzimidazole)sulfone, poly-2,2'-(m-phenylene)-5,5'-di(benzimidazole)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, etc., and include their derivatives (substituted (e.g., fluorinated) and / or branched). In some examples, the PBI polymer may be a copolymer containing one or more additional repeating units, whether or not the main chain, side chains, or both contain benzimidazole units.

[0084] PBI polymer (weakly basic) can be converted into a highly durable acidic polymer by a simple acid-base conjugation reaction with a strong acid. The resulting polybenzimidazolium polymer (referred to herein as "PBI") + The polymer (referred to as "PBI polymer") has acidic aromatic units that are conjugate acids of the weakly basic aromatic units of the original PBI polymer. + The polymer is ionic, strongly acidic, and highly cationically conductive. Under aqueous conditions in water electrolysis and hydrogen fuel cells, polybenzimidazolium units readily dissociate into neutral PBI and hydrated protons (H3O). + It forms an equilibrium mixture containing ). Therefore, the readily dissociable polybenzimidazolium units can function as proton transporters. As a result, PBI + The polymer can be applied to ionomer and proton exchange membrane (PEM) applications. Acidic PBI + The polymer is a simple and progressive alternative to existing poly(phosphate)(PPA) doped polymers (e.g., PBI-PPA).

[0085] In PBI polymer molecules, the tertiary amine of the benzimidazole unit (e.g., the N of the N=C group) reacts with a strong acid in an acid-base reaction to produce a benzimidazolium unit (a conjugate acid of the weakly basic benzimidazole unit) and a counteranion (a conjugate base of the strong acid) ionically bonded to the benzimidazolium unit.

[0086] PBI + The molecular structure of the polymer suggests that the non-coordinating counteranions do not play a direct role in the electrochemical process. This indicates that the main function of the counteranions is PBI. + This is because it is a neutralization of positive charges within the polymer structure. As a result, the non-coordinating counter anions do not directly or indirectly participate in the electrochemical process and do not inhibit the catalytic cycle by binding to the metal catalyst.

[0087] In some cases, the counter anion is tetrafluoroboric acid ([BF4 -It contains ]), which is a non-coordinating anion containing tetracoordinate boron and is stable and inert during electrochemical processes. Examples of other suitable counteranions include hexafluorophosphate ([PF6 - ]), hexafluoroantimonic acid ([SbF4 - Examples include BF2, AlF3, fluorinated bismuth, fluorinated antimony, fluorinated phosphorus, fluorinated tin, fluorinated zirconium, and fluorinated titanium.

[0088] PBI as described in this specification + Polymers are all inherently ionic and are similar to ionic liquids, which are known to promote / accelerate electrochemical reactions. Below are proton-conducting polymers (PBIs). + Examples of polymers and methods for producing them are provided.

[0089] Figure 1 shows a proton-conducting PBI ionically bonded to a tetrafluoroborate pair anion. + An example of a reaction scheme for producing a polymer is shown. As shown in Figure 1, the m-PBI polymer is combined with fluoroboric acid (HBF4). Fluoroboric acid is a very strong acid and reacts with the tertiary nitrogen of the benzimidazole unit in an acid-base reaction. This reaction produces a benzimidazole unit and a tetrafluoroboric acid counteranion (BF4) that is ionically bonded to the benzimidazole unit. - The following is generated: The benzimidazolium unit is a strong conjugate acid of the weakly basic aromatic benzimidazole unit. The tetrafluoroborate counteranion is a conjugate base of fluoroboric acid. The tetrafluoroborate counteranion contains a four-coordinate negative boron atom and is non-coordinating and non-oxidizing, thus exhibiting high stability under harsh electrochemical conditions such as water electrolysis and fuel cells. Furthermore, it does not bind to metal catalysts and therefore does not cause catalyst poisoning.

[0090] In the example in Figure 1, only one benzimidazole unit in each repeating unit is converted to a benzimidazolium unit. In other examples, both benzimidazole units in each repeating unit are converted to benzimidazolium units. In yet another example, the desired proton loading can be adjusted by controlling the molar ratio of HBF4 to benzimidazole units.

[0091] Figure 2 shows PBI ionically bound to a tetrafluoroborate counter anion. + Another reaction scheme for producing polymers is shown. In the first step, m-PBI is combined with hydrofluoric acid (HF). Hydrofluoric acid is a very strong acid and reacts with the tertiary nitrogen of the benzimidazole unit in an acid-base reaction. In the first step, an intermediate PBI has a benzimidazolium unit ionically bonded to the fluoride counteranion. + A polymer is produced. In the second step (fluoride treatment step), the intermediate PBI is formed. + The polymer is combined with boron trifluoride (e.g., BF3·Et2O). The boron trifluoride combines with the fluoride counter anion to form a tetrafluoroborate counter anion, resulting in a PBI where the benzimidazolium unit and the tetrafluoroborate counter ion are ionically bonded. + A polymer is obtained.

[0092] Figure 3 shows PBI ionically bound to one of several types of counteranions. + The reaction scheme for producing the polymer is shown. In the first step, m-PBI is combined with hydrofluoric acid (HF). Hydrofluoric acid is a very strong acid and reacts with the tertiary nitrogen of the benzimidazole unit in an acid-base reaction. In the first step, an intermediate PBI having a benzimidazolium unit ionically bonded to the fluoride counteranion is formed. + A polymer is produced. In the second step (fluoride treatment step), the intermediate PBI is formed. + The polymer, general formula MF n It is combined with a metal fluoride represented by (M is Be, Al, Bi, Sb, P, Sn, Zr, Ti, and n is the valence of M). The metal fluoride combines with a fluoride counter anion to form the general formula [MF(n+1)].- forms a counter anion represented by this, thereby forming a strongly acidic PBI + polymer is obtained.

[0093] Figure 4 shows another reaction scheme for producing a PBI + polymer ionically bonded to a tetrafluoroborate counter anion. As a first step, m-PBI is combined with an acid represented by the general formula HA (A is F, Cl, Br, HSO4, SO4, H2PO4, HPO4, PO4, or a polyphosphate anion derived from any polyphosphoric acid). Examples of suitable polyphosphoric acids include, but are not limited to, diphosphoric acid, triphosphoric acid, tetraphosphoric acid, and trimeta phosphoric acid. The acid HA reacts with the tertiary nitrogen of the benzimidazole unit by an acid-base reaction. In the first step, an intermediate PBI - having a benzimidazolium unit ionically bonded to the counter anion A + polymer is formed. As a second step (anion exchange step), the counter ion A - is exchanged with a tetrafluoroborate counter anion (BF4 - ) (BF4 - is a non-coordinating counter anion). The second step is carried out by combining a metal tetrafluoroborate compound (MBF4) (BF4 - is a tetrafluoroborate anion, M is Na + , K + , Cs + , NH4 + , or a tetraalkylammonium (R4N + , each R is independently hydrogen or a substituted / unsubstituted alkyl group having 1 to 20, 1 to 10, 1 to 8, 1 to 6, or 1 to 4 carbon atoms; including but not limited to methyl, ethyl, propyl, butyl, etc.). The metal tetrafluoroborate compound binds to the counter anion A - to form a salt MA, and the tetrafluoroborate anion (BF4 - ) replaces A - as the counter anion that binds to the acidic aromatic unit. Thereby, a strongly acidic PBI + polymer ionically bonded to a non-coordinating tetrafluoroborate counter anion is obtained.

[0094] The examples and reaction schemes described above can be extended to other applications, such as the formation of conjugated acid type proton exchange polymers by crosslinking fluoroboric acid-functionalized polymers with basic aromatic polymers. In some examples, the fluoroboric acid-functionalized polymer is a sulfonic acid-functionalized polymer (e.g., Nafion® or Aquivion®) in which one or more pendant sulfonic acid groups react with BF3 to give the following structures having pendant fluoroboric acid groups (-BF3H) (e.g., in one or more side chains or side groups). [ka]

[0095] A fluoroboric acid-functionalized polymer is combined with PBI, PANI, or any other basic aromatic polymer described herein. The pendant fluoroboric acid group reacts with the basic aromatic units of the basic aromatic polymer by an acid-base reaction similar to the acid-base reaction shown in Figure 1, thereby crosslinking the fluoroboric acid-functionalized polymer and the basic aromatic polymer. The crosslinked conjugate acid proton exchange polymer molecule comprises a first polymer molecule having an acidic aromatic unit (the acidic aromatic unit being the conjugate acid of the basic aromatic unit) and a second polymer molecule having a trifluoroboric acid group (the trifluoroboric acid group being the conjugate base of the fluoroboric acid group). The first and second polymer molecules are crosslinked by ionic bonds between the acidic aromatic unit and the trifluoroboric acid group. Examples of crosslinked conjugate acid proton exchange polymers include, but are not limited to, PBI. + -PFSA (for example, PBI) + -Nafion(TM), PBI + -Aquivion (registered trademark), PBI + -SPSF (Sulfonated Polysulfone), PBI +Examples include -SPEEK (sulfonated poly(etherketone)), PANI-PFSA (e.g., PANI-Nafion®, PANI-Aquivion®), PANI-SPSF, PANI-SPEEK, PPy-PFSA (e.g., PPy-Nafion®, PPy-Aquivion®), PPy-SPSF, and PPy-SPEEK. In some examples, more than two polymers, for example, three or four polymers, may be crosslinked.

[0096] Those skilled in the art will understand that fluoroboric acid-functionalized polymers other than fluoroboric acid-functionalized sulfonic acid polymers can also be crosslinked with basic aromatic polymers. Fluoroboric acid-functionalized polymers include, but are not limited to, any polymer having pendant fluoroboric acid groups, such as any fluoroboric acid-functionalized polymer described in International Application PCT / US2024 / 015409 (filed February 12, 2024), the contents of which are incorporated herein by reference in their entirety. Crosslinking fluoroboric acid-functionalized polymers with basic aromatic polymers in this manner improves the dimensional stability of the crosslinked conjugated acid proton exchange polymer.

[0097] Figure 5 shows PEMs and / or ionomers (e.g., PBIs) made from conjugated acid type proton exchange polymers. + An example of a proton exchange membrane water electrolysis system 500 (PEM water electrolysis system 500) incorporating a polymer (PEM and / or ionomer) is shown. The PEM water electrolysis system 500 uses electrical energy to decompose water into oxygen (O2) and hydrogen (H2) through electrochemical reactions. The configuration of the PEM water electrolysis system 500 is illustrative and not limited thereto. Conjugated acid type proton exchange polymers can be incorporated in other suitable configurations and in other suitable water electrolysis systems.

[0098] As shown in FIG. 5, the PEM water electrolysis system 500 includes a membrane electrode assembly (MEA) 502, porous transport layers 504-1 and 504-2 (e.g., gas diffusion layers), bipolar plates 506-1 and 506-2, and a power source 508. The PEM water electrolysis system 500 may further include additional or alternative components (not shown in FIG. 5) that contribute to a particular implementation.

[0099] MEA 502 includes a PEM 510 and first and second catalyst layers 512-1 and 512-2 disposed on both sides thereof. The PEM 510 is impermeable to gases such as hydrogen and oxygen, while selectively conducting cations such as protons (H + ) and electrically insulating the first catalyst layer 512-1 and the second catalyst layer 512-2. The PEM 510 may be implemented by a conjugated acid type proton exchange polymer (e.g., PBI + polymer) described herein, or may be implemented by other suitable polymers.

[0100] The first catalyst layer 512-1 and the second catalyst layer 512-2 are conductive electrodes and include a structure in which electrochemical catalyst particles (not shown, such as platinum group metals, metal alloys, and / or metal oxides) are supported on a catalyst carrier. These catalyst layers may further include one or more ionomers mixed with the catalyst carrier and the electrochemical catalyst particles. The ionomer may be implemented by a conjugated acid type proton exchange polymer (e.g., PBI + polymer) described herein, or may be other suitable ionomers. In some examples, the ionomer is implemented by a conjugated acid type proton exchange polymer having electrical conductivity (e.g., conjugated acid type proton exchange polyaniline).

[0101] MEA 500 is disposed between the porous transport layers 504-1 and 504-2, and these porous transport layers are further disposed between the bipolar plates 506-1 and 506-2. Flow paths 514-1 and 514-2 are provided between the bipolar plate 506 and the porous transport layer 504.

[0102] In MEA502, the first catalyst layer 512-1 functions as the anode, and the second catalyst layer 512-2 functions as the cathode. When power is supplied to the PEM water electrolysis system 500 from the power supply 508, an oxygen evolution reaction (OER) occurs at the anode (first catalyst layer) 512-1, and is promoted by electrochemical catalyst particles supported on the catalyst support in the first catalyst layer / anode 512-1. The OER is represented by the following electrochemical half-reaction. 2H₂O → O₂ + 4H + +4e -

[0103] Protons are conducted from the first catalyst layer / anode 512-1 to the second catalyst layer / cathode 512-2 via PEM510, and electrons are conducted from the first catalyst layer / anode 512-1 to the second catalyst layer / cathode 512-2 through conductive paths around PEM510. PEM510 is a proton (H + ) and water can be transported from the first catalyst layer / anode 512-1 to the second catalyst layer / cathode 512-2, while being impermeable to oxygen and hydrogen. In the second catalyst layer / cathode 512-2, a hydrogen evolution reaction (HER) occurs and is promoted by electrochemical catalyst particles supported on the catalyst support in the same layer. HER is represented by the following electrochemical half-reaction. 4H + +4e - →2H2

[0104] OER and HER are complementary electrochemical reactions that decompose water through electrolysis, and are represented by the following total reaction. 2H2O → 2H2 + O2

[0105] Figure 6 shows PEMs and / or ionomers (e.g., PBIs) made from conjugated acid type proton exchange polymers. +An example of a proton exchange membrane fuel cell 600 (PEM fuel cell 600) containing a polymer (PEM and / or ionomer) is shown. The PEM fuel cell 600 generates electricity as a result of an electrochemical reaction. In this example, hydrogen gas (H2) and oxygen gas (O2) are reacted to produce water and electricity. The configuration of the PEM fuel cell 600 is illustrative and not limited thereto.

[0106] As shown in Figure 6, the PEM fuel cell 600 includes a membrane electrode assembly (MEA) 602, porous transport layers 604-1 and 604-2 (e.g., a gas diffusion layer), and dipole plates 606-1 and 606-2. An electrical load 608 is electrically connected to the MEA 602 and can be driven by the PEM fuel cell 600. The PEM fuel cell 600 may further include additional or alternative components (not shown in Figure 6) that contribute to a particular implementation.

[0107] MEA602 includes PEM610 and a first catalyst layer 612-1 and a second catalyst layer 612-2 positioned on either side thereof. PEM610 is impermeable to gases such as hydrogen and oxygen, while being impermeable to protons (H + The first catalyst layer 612-1 and the second catalyst layer 612-2 are electrically insulated while selectively conducting cations such as ). PEM610 can be implemented by any suitable PEM described herein, for example, a conjugated acid type proton exchange polymer described or assumed herein.

[0108] The first catalyst layer 612-1 and the second catalyst layer 612-2 are conductive electrodes and include a configuration in which electrochemical catalyst particles (not shown; such as platinum group metals, metal alloys, and / or metal oxides) are supported on a catalyst support. These catalyst layers may further include one or more ionomers mixed with the catalyst support and electrochemical catalyst particles. The ionomer can be implemented by any suitable polymer or ionomer described herein, for example, a conjugated acid type proton exchange polymer described herein, or any other suitable ionomer. In some examples, the ionomer is implemented by an electrically conductive conjugated acid type proton exchange polymer (e.g., a conjugated acid type proton exchange polyaniline).

[0109] The MEA602 is positioned between porous transport layers 604-1 and 604-2, and these porous transport layers are further positioned between dipole plates 606-1 and 606-2, with a channel 614 provided between them. In the MEA602, the first catalyst layer 612-1 functions as the cathode, and the second catalyst layer 612-2 functions as the anode. The first catalyst layer / cathode 612-1 and the anode 612-2 are electrically connected to a load 608, and the power generated in the PEM fuel cell 600 drives the load 608.

[0110] During operation of the PEM fuel cell 600, hydrogen gas (H2) flows into the anode side and oxygen gas (O2) flows into the cathode side. In the second catalyst layer / anode 612-2, hydrogen molecules are converted into protons (H2) according to the hydrogen oxidation reaction (HOR) shown in the following equation. + ) and electrons (e - It is catalytically decomposed into ). This reaction is promoted by electrochemical catalyst particles supported on a catalyst support in the same layer. 2H2→4H + +4e -

[0111] Protons are conducted from anode 612-2 to the first catalyst layer / cathode 612-1 via PEM610, and electrons are conducted from the second catalyst layer / anode 612-2 to the first catalyst layer / cathode 612-1 via the external conductive path of PEM610 and load 608. In the first catalyst layer / cathode 612-1, protons and electrons react with oxygen gas according to the following oxygen reduction reaction (ORR). This reaction is facilitated by electrochemical catalyst particles supported on the catalyst support in the same layer. O2 + 4H + +4e - →2H2O

[0112] Therefore, the overall electrochemical reaction in the PEM fuel cell 600 is given by the following equation. 2H2 + O2 → 2H2O

[0113] In this entire reaction, the PEM fuel cell 600 produces water in the first catalyst layer / cathode 612-1. The water can move from the first catalyst layer / cathode 612-1 to the second catalyst layer / anode 612-2 via the PEM 610 and be discharged from the cathode and / or anode outlets. In the entire reaction, electrons produced at the anode drive the load 608.

[0114] In the examples shown in Figures 14 and 5, MEA502 and MEA602 include catalyst layers 512 / 412 formed on PEM510 / 410. In alternative configurations, the catalyst layers 512 / 412 may be coated onto PEM110 / 410, thereby forming a catalyst coating film (CCM). For example, the catalyst layers 512 / 212 may be formed by a one-pot or step-by-step method and spray-applied to PEM510 / 410.

[0115] This specification describes examples of using conjugated acid proton exchange polymers in electrochemical cell applications such as water electrolysis and hydrogen fuel cells, but these polymers can also be used in other applications. For example, the pK of conjugated acid proton exchange polymers a It can be controlled to the desired level according to various applications and is applicable to electrochemical processes for ammonia production, etc. For example, the pK of conjugated acid type proton exchange polymers a The pK of conventional PEM currently used in ammonia synthesis processes a It can be controlled to a higher degree.

[0116] This specification describes and illustrates various examples and embodiments. However, it is clear that various changes and modifications can be made and additional embodiments can be implemented without departing from the spirit of the following claims. For example, certain features of one embodiment described herein may be combined with or substituted for features of other embodiments. Therefore, the description and drawings herein should be understood as illustrative rather than restrictive.

[0117] The advantages and features of this disclosure can be further illustrated by the following embodiments. [Examples]

[0118] Example 1: A conjugated acid type proton exchange polymer molecule having an acidic aromatic unit in the main chain or side chain, wherein the acidic aromatic unit is a conjugate acid of a basic aromatic unit, and the molecule has a non-coordinating counteranion ionically bonded to the acidic aromatic unit.

[0119] Example 2: The conjugate acid type proton exchange polymer molecule described in Example 1, wherein the non-coordinating counteranion is a conjugate base of a strong acid.

[0120] Example 3: The conjugated acid type proton exchange polymer molecule described in Example 1, wherein the non-coordinating counteranion contains tetrafluoroboric acid.

[0121] Example 4: The conjugated acid type proton exchange polymer molecule described in Example 1, wherein the non-coordinating counteranion contains hexafluorophosphate.

[0122] Example 5: The conjugated acid type proton exchange polymer molecule described in Example 1, wherein the non-coordinating counteranion contains hexafluoroantimonic acid.

[0123] Example 6: The above non-coordinating counteranion is benzenesulfonate-trifluoroboric acid (PhSO3(BF3) - A conjugated acid type proton exchange polymer molecule as described in Example 1, comprising ).

[0124] Example 7: The above non-coordinating counteranion is sulfatose-di(trifluoroboric acid)(SO4(BF3)2 2- A conjugated acid type proton exchange polymer molecule as described in Example 1, comprising ).

[0125] Example 8: The conjugated acid type proton exchange polymer molecule described in Example 1, wherein the non-coordinating counteranion comprises beryllium fluoride, aluminum fluoride, bismuth fluoride, antimony fluoride, phosphorus fluoride, tin fluoride, zirconium fluoride, or titanium fluoride.

[0126] Example 9: The above non-coordinating pair anion has the general formula [MF(n+1)] - A conjugated acid type proton exchange polymer molecule as described in Example 1, comprising a metallic fluoroboric acid represented by , where M is beryllium (Be), aluminum (Al), bismuth (Bi), antimony (Sb), phosphorus (P), tin (Sn), zirconium (Zr), or titanium (Ti), and n corresponds to the valence of M.

[0127] Example 10: The conjugated acid type proton exchange polymer molecule described in Example 1, wherein the basic aromatic unit comprises aniline or an aniline derivative.

[0128] Example 11: The conjugated acid type proton exchange polymer molecule described in Example 1, wherein the basic aromatic unit comprises an imidazole group or a benzimidazole group.

[0129] Example 12: The conjugated acid type proton exchange polymer molecule described in Example 1, wherein the conjugated acid type proton exchange polymer molecule is electrically conductive.

[0130] Example 13: A method for producing a conjugate acid type proton exchange polymer molecule, comprising the steps of: 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 counteranion to the acidic aromatic unit.

[0131] Example 14: The method according to Example 13, wherein the steps of protonating the basic aromatic unit and ionically bonding the acidic aromatic unit with the non-coordinating counteranion include an acid-base reaction between the basic aromatic unit and an acid, and the conjugate base of the acid includes the non-coordinating counteranion.

[0132] Example 15: The method according to Example 14, wherein the acid contains fluoroboric acid.

[0133] Example 16: The method according to Example 14, wherein the acid contains hexafluorophosphate.

[0134] Example 17: The method according to Example 14, wherein the acid contains fluoroantimonic acid.

[0135] Example 18: The method according to Example 14, wherein the acid comprises a sulfuric acid-boron trifluoride complex having the following general structure. [ka]

[0136] Example 19: The method according to Example 14, wherein the acid comprises a benzenesulfonic acid-boron trifluoride complex having the following general structure. [ka]

[0137] Example 20: The method according to Example 14, wherein the acid contains a benzenedisulfonic acid-boron trifluoride complex having the following general structure. [ka]

[0138] Example 21: The method according to Example 14, wherein the acid comprises phenyltrifluoroboric acid having the following general structure, or 1,4-di(trifluoroboron)phenylic acid having the following general structure. [ka]

[0139] Example 22: The method according to Example 14, wherein the acid contains a phosphoric acid-boron trifluoride complex having the following general structure. [ka]

[0140] Example 23: The method according to Example 13, wherein the step of protonating the basic aromatic unit includes reacting the basic aromatic unit with hydrofluoric acid by an acid-base reaction, the conjugate base of the hydrofluoric acid includes a fluoride counteranion ionically bonded to the acidic aromatic unit, and the step of ionically bonding the acidic aromatic unit with the non-coordinating counteranion includes reacting the fluoride counteranion with boron trifluoride.

[0141] Example 24: The step of protonating the basic aromatic unit includes reacting the basic aromatic unit with hydrofluoric acid by an acid-base reaction, wherein the conjugate base of the hydrofluoric acid includes a fluoride counteranion ionically bonded to the acidic aromatic unit, and the step of ionically bonding the acidic aromatic unit and the non-coordinating counteranion comprises the fluoride counteranion having the general formula MF n The method according to Example 13, comprising reacting with a metal fluoride represented by , where M is beryllium (Be), aluminum (Al), bismuth (Bi), antimony (Sb), phosphorus (P), tin (Sn), zirconium (Zr), or titanium (Ti), and n corresponds to the valence of M.

[0142] Example 25: The method according to Example 13, wherein the step of protonating the basic aromatic unit includes reacting the basic aromatic unit with an acid by an acid-base reaction, the conjugate base of the acid includes a coordinating counter anion ionically bonded to the acidic aromatic unit, and the step of ionically bonding the acidic aromatic unit with the non-coordinating counter anion includes replacing the coordinating counter anion with the non-coordinating counter anion by an anion exchange reaction.

[0143] Example 26: The method according to Example 25, wherein the acid is represented by the general formula HA, and A is F, Cl, Br, HSO4, SO4, H2PO4, HPO4, PO4, or a polyphosphate anion.

[0144] Example 27: The above anion exchange reaction involves reacting with a metal tetrafluoroborate compound represented by the general formula MBF4, where M is a sodium ion (Na + ), potassium ions (K + ), cesium ions (Cs + ), ammonium (NH4 + ), or general formula R4N + The method according to Example 25, wherein the tetraalkylammonium is represented by , and each R is independently hydrogen or an alkyl group that is all or partly substituted or unsubstituted.

[0145] Example 28: The method according to Example 13, wherein the basic aromatic polymer molecule includes a polyaniline polymer.

[0146] Example 29: The method according to Example 13, wherein the basic aromatic polymer molecule comprises a polybenzimidazole polymer.

[0147] Example 30: The method according to Example 13, wherein the basic aromatic polymer molecule is electrically conductive.

[0148] Example 31: A membrane electrode assembly comprising a first catalyst layer, a second catalyst layer, and a proton exchange membrane disposed between the first catalyst layer and the second catalyst layer, wherein at least one of the first catalyst layer, the second catalyst layer, or the proton exchange membrane is formed from a conjugate acid type proton exchange polymer molecule having acidic aromatic units in its main chain or side chain, wherein the acidic aromatic units are conjugate acids of basic aromatic units, and non-coordinating counter anions ionically bonded to the acidic aromatic units.

[0149] Example 32: The membrane electrode assembly according to Example 31, wherein the conjugated acid type proton exchange polymer is electrically conductive, and at least one of the first catalyst layer or the second catalyst layer is formed from the conjugated acid type proton exchange polymer.

[0150] Example 33: The membrane electrode assembly according to Example 32, wherein the proton exchange membrane is formed from different conjugated acid type proton exchange polymers that are electrically nonconductive.

[0151] Example 34: The membrane electrode assembly according to Example 31, wherein the conjugated acid type proton exchange polymer contains a polybenzimidazolium polymer.

[0152] Example 35: The membrane electrode assembly according to Example 31, wherein the conjugated acid type proton exchange polymer contains a polyaniline polymer.

[0153] Example 36: A method for producing a conjugated acid type proton exchange polymer, comprising the step of crosslinking a fluoroboric acid-functionalized polymer molecule with a basic aromatic polymer molecule.

[0154] Example 37: The method according to Example 36, wherein the fluoroboric acid-functionalized polymer molecule comprises a polyfluorosulfonic acid polymer molecule in which one or more sulfonic acid groups are functionalized with fluoroboric acid groups.

[0155] Example 38: The method according to Example 36, wherein the basic aromatic polymer molecule comprises a polybenzimidazole (PBI) polymer molecule.

[0156] Example 39: The method according to Example 36, wherein the basic aromatic polymer molecule includes a polyaniline (PANI) polymer molecule.

[0157] Example 40: The method according to Example 36, wherein the step of crosslinking the fluoroboric acid-functionalized polymer molecule with the basic aromatic polymer molecule includes reacting the fluoroboric acid group of the fluoroboric acid-functionalized polymer molecule with the basic aromatic unit of the basic aromatic polymer molecule by an acid-base reaction.

[0158] Example 41: A conjugate acid type proton exchange polymer comprising: a first polymer molecule having an acidic aromatic unit, wherein the acidic aromatic unit is a conjugate acid of a basic aromatic unit; and a second polymer molecule containing a trifluoroboric acid group, wherein the trifluoroboric acid group is a conjugate base of a fluoroboric acid group, wherein the first polymer molecule and the second polymer molecule are crosslinked by ionic bonds between the acidic aromatic unit and the trifluoroboric acid group.

[0159] Example 42: The conjugated acid type proton exchange polymer according to Example 41, wherein the first polymer molecule comprises a polybenzimidazole (PBI) polymer.

[0160] Example 43: The conjugated acid type proton exchange polymer according to Example 41, wherein the first polymer molecule contains a polyaniline (PANI) polymer.

[0161] Example 44: The conjugated acid type proton exchange polymer according to Example 41, wherein the second polymer molecule comprises a fluoroboric acid-functionalized sulfonic acid polymer.

Claims

1. A conjugated acid type proton exchange polymer molecule, It has an acidic aromatic unit in its main chain or side chain, and the acidic aromatic unit is a conjugate acid of the basic aromatic unit. A conjugated acid type proton exchange polymer molecule containing a non-coordinating counter anion ionically bonded to the aforementioned acidic aromatic unit.

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

3. The conjugated acid type proton exchange polymer molecule according to claim 1, wherein the non-coordinating counter anion contains tetrafluoroboric acid.

4. The conjugated acid type proton exchange polymer molecule according to claim 1, wherein the non-coordinating counter anion comprises hexafluorophosphate.

5. The conjugated acid type proton exchange polymer molecule according to claim 1, wherein the non-coordinating counter anion contains hexafluoroantimonic acid.

6. The non-coordinating counter anion is benzenesulfonate-trifluoroboric acid (PhSO ３ (BF ３ ) － A conjugated acid type proton exchange polymer molecule according to claim 1, comprising ).

7. The aforementioned non-coordinating counter anion is sulfatose di(trifluoroboric acid) (SO ４ (BF ３ ) ２ ２－ A conjugated acid type proton exchange polymer molecule according to claim 1, comprising ).

8. The conjugated acid type proton exchange polymer molecule according to claim 1, wherein the non-coordinating counteranion comprises beryllium fluoride, aluminum fluoride, bismuth fluoride, antimony fluoride, phosphorus fluoride, tin fluoride, zirconium fluoride, or titanium fluoride.

9. The non-coordinating counter anion contains a metal fluoroboric acid represented by 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 corresponds to the valence of M, the conjugated acid type proton exchange polymer molecule according to claim 1.

10. The conjugated acid type proton exchange polymer molecule according to claim 1, wherein the basic aromatic unit comprises aniline or an aniline derivative.

11. The conjugated acid type proton exchange polymer molecule according to claim 1, wherein the basic aromatic unit comprises an imidazole group or a benzimidazole group.

12. The conjugated acid type proton exchange polymer molecule according to claim 1, wherein the conjugated acid type proton exchange polymer molecule is electrically conductive.

13. A method for producing conjugated acid type proton exchange polymer molecules, A step of 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, A manufacturing method comprising the step of ionically bonding the aforementioned acidic aromatic unit with a non-coordinating counter anion.

14. The manufacturing method according to claim 13, wherein the steps of protonating the basic aromatic unit and ionically bonding the acidic aromatic unit with the non-coordinating counter anion include an acid-base reaction between the basic aromatic unit and an acid, and the conjugate base of the acid includes the non-coordinating counter anion.

15. The method for producing the product according to claim 14, wherein the acid includes fluoroboric acid.

16. The method for producing the product according to claim 14, wherein the acid contains hexafluorophosphate.

17. The manufacturing method according to claim 14, wherein the acid comprises fluoroantimonic acid.

18. The method for producing the product according to claim 14, wherein the acid comprises a sulfuric acid-boron trifluoride complex having the following general structure. 【Chemistry 1】

19. The method for producing the product according to claim 14, wherein the acid comprises a benzenesulfonic acid-boron trifluoride complex having the following general structure. 【Chemistry 2】

20. The method for producing the product according to claim 14, wherein the acid comprises a benzenedisulfonic acid-boron trifluoride complex having the following general structure. 【Transformation 3】

21. The aforementioned acid is phenyltrifluoroboric acid having the following general structure. 【Chemistry 4】 Alternatively, the method for producing the product according to claim 14, comprising 1,4-di(trifluoroboron)phenyl acid having the following general structure. 【Transformation 5】

22. The method for producing the product according to claim 14, wherein the acid comprises a phosphoric acid-boron trifluoride complex having the following general structure. 【Transformation 6】

23. The step of protonating the basic aromatic unit includes reacting the basic aromatic unit with hydrofluoric acid by an acid-base reaction, wherein the conjugate base of the hydrofluoric acid includes a fluoride pair anion ionically bonded to the acidic aromatic unit. The manufacturing method according to claim 13, wherein the step of ionically bonding the acidic aromatic unit and the non-coordinating counter anion includes reacting the fluoride counter anion with boron trifluoride.

24. The step of protonating the basic aromatic unit includes reacting the basic aromatic unit with hydrofluoric acid by an acid-base reaction, wherein the conjugate base of the hydrofluoric acid includes a fluoride pair anion ionically bonded to the acidic aromatic unit. The step of ionically bonding the acidic aromatic unit and the non-coordinating counter anion is performed by forming the fluoride counter anion with the general formula MF ｎ The manufacturing method according to claim 13, comprising reacting with a metal fluoride represented by , where M is beryllium (Be), aluminum (Al), bismuth (Bi), antimony (Sb), phosphorus (P), tin (Sn), zirconium (Zr), or titanium (Ti), and n corresponds to the valence of M.

25. The step of protonating the basic aromatic unit includes reacting the basic aromatic unit with an acid by an acid-base reaction, wherein the conjugate base of the acid includes a coordinating counter anion ionically bonded to the acidic aromatic unit. The manufacturing method according to claim 13, wherein the step of ionically bonding the acidic aromatic unit and the non-coordinating counter anion includes performing an anion exchange reaction to replace the coordinating counter anion with the non-coordinating counter anion.

26. The acid is represented by the general formula HA, where A is F, Cl, Br, or HSO4. ４ SO ４ , H ２ PO ４ HPO ４ , PO ４ The manufacturing method according to claim 25, wherein the polyphosphate anion is used.

27. The aforementioned anion exchange reaction is based on the general formula MBF ４ This involves reacting a metal tetrafluoroborate compound represented by , where M is a sodium ion (Na ＋ ), potassium ions (K ＋ ), cesium ions (Cs ＋ ), ammonium (NH ４ ＋ ), or general formula R ４ N ＋ The method for producing a tetraalkylammonium represented by , wherein each R is independently hydrogen or an alkyl group that is all or partly substituted or unsubstituted.

28. The manufacturing method according to claim 13, wherein the basic aromatic polymer molecule includes a polyaniline polymer.

29. The method for producing the basic aromatic polymer molecule according to claim 13, wherein the basic aromatic polymer molecule comprises a polybenzimidazole polymer.

30. The manufacturing method according to claim 13, wherein the basic aromatic polymer molecule has electrical conductivity.

31. First catalyst layer, A second catalyst layer, and A membrane electrode assembly comprising a proton exchange membrane disposed between the first catalyst layer and the second catalyst layer, At least one of the first catalyst layer, the second catalyst layer, or the proton exchange membrane, Acidic aromatic units having acidic aromatic units in the main chain or side chain, wherein the acidic aromatic units are conjugate acids of basic aromatic units, and A membrane electrode assembly formed from a conjugated acid type proton exchange polymer molecule containing a non-coordinating counteranion ionically bonded to the aforementioned acidic aromatic unit.

32. The aforementioned conjugated acid type proton exchange polymer has electrical conductivity, The membrane electrode assembly according to claim 31, wherein at least one of the first catalyst layer or the second catalyst layer is formed from the conjugated acid type proton exchange polymer.

33. The membrane electrode assembly according to claim 32, wherein the proton exchange membrane is formed from different conjugated acid type proton exchange polymers having electrical nonconductivity.

34. The membrane electrode assembly according to claim 31, wherein the conjugated acid type proton exchange polymer comprises a polybenzimidazolium polymer.

35. The membrane electrode assembly according to claim 31, wherein the conjugated acid type proton exchange polymer comprises a polyaniline polymer.

36. A method for producing conjugated acid type proton exchange polymers, A manufacturing method comprising the step of crosslinking fluoroboric acid-functionalized polymer molecules with basic aromatic polymer molecules.

37. The method for producing a polyfluorosulfonic acid polymer molecule according to claim 36, wherein the fluoroboric acid-functionalized polymer molecule comprises a polyfluorosulfonic acid polymer molecule in which one or more sulfonic acid groups are functionalized with fluoroboric acid groups.

38. The method for producing a basic aromatic polymer molecule according to claim 36, wherein the basic aromatic polymer molecule comprises a polybenzimidazole (PBI) polymer molecule.

39. The method for producing the basic aromatic polymer molecule according to claim 36, wherein the basic aromatic polymer molecule includes a polyaniline (PANI) polymer molecule.

40. The step of crosslinking the fluoroboric acid-functionalized polymer molecule with the basic aromatic polymer molecule is The manufacturing method according to claim 36, comprising reacting the fluoroboric acid group of the fluoroboric acid-functionalized polymer molecule with the basic aromatic unit of the basic aromatic polymer molecule by an acid-base reaction.

41. A conjugated acid type proton exchange polymer, A first polymer molecule having an acidic aromatic unit, wherein the acidic aromatic unit is a conjugate acid of a basic aromatic unit, A second polymer molecule comprising a trifluoroboric acid group, wherein the trifluoroboric acid group is a conjugate base of the fluoroboric acid group, A conjugated acid type proton exchange polymer in which the first polymer molecule and the second polymer molecule are crosslinked by ionic bonds between the acidic aromatic unit and the trifluoroboric acid group.

42. The conjugated acid type proton exchange polymer according to claim 40, wherein the first polymer molecule comprises a polybenzimidazole (PBI) polymer.

43. The conjugated acid type proton exchange polymer according to claim 40, wherein the first polymer molecule comprises a polyaniline (PANI) polymer.

44. The conjugated acid type proton exchange polymer according to claim 40, wherein the second polymer molecule comprises a fluoroboric acid-functionalized sulfonic acid polymer.

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