Process for synthesis of 1, 6-diazabicyclo [4.4.4] tetradecane-1, 6-onium cation structures, use of said cation structures in electrochemical applications and polymers comprising said cation structures

Abstract

Described herein are methods of synthesizing 1, 6-diazabicyclo [4.4. 4] tetradecane-1, 6-onium (in-DBD) cationic structures, methods of integrating in-DBD cationic structures into polymers, and the use of in-DBD polymers in electrochemical applications, such as anion exchange membranes (AEM). The configuration of the in-DBD enables the in-DBD to carry cationic charges through stable protons in an aliphatic cage formed by a three-dimensional structure of the in-DBD, and the in-DBD is anchored between two nitrogen atoms through symmetrical hydrogen bonds in bridgeheads. Through the synthesis method of in-DBD and the application thereof in various scenarios, an organic cation-hydroxide is realized that remains stable at extremely low hydration levels and high temperatures (80 DEG C, RHlt; 10%) and shows hydroxide stability several orders of magnitude higher than that of conventional cations.

Description

Technical Field

[0001] This disclosure relates to a method for synthesizing a 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium (in-DBD) cationic structure, a polymer comprising the in-DBD cationic structure, and the use of the in-DBD cationic structure in electrochemical applications such as anion exchange membranes (AEMs), catalyst inks, catalyst-coated membranes, fuel cells, water electrolyzers, and carbon dioxide and / or carbon monoxide electrolyzers. Background Technology

[0002] The cost of electrochemical devices such as proton exchange membrane fuel cells and water electrolyzers is closely related to the cost of platinum group metal electrocatalysts used to avoid degradation in strongly acidic media. Electrocatalysis in alkaline environments allows for the use of less expensive metals, but requires the use of anion exchange membranes (AEMs) containing polymers with fixed cationic functional groups as conductors of hydroxide ions.

[0003] Operating electrochemical devices in alkaline environments is challenging because the nucleophilicity of hydroxides tends to degrade organic molecules and polymers. This degradation risk is exacerbated under conditions of decreasing relative humidity (RH). While some AEM technologies have been explored, such as AEM water electrolyzers, AEM fuel cells, and CO / CO2 electrolyzers operating at high temperatures or dry cathodes, these technologies all rely on humidified gas inputs. However, localized dehydration zones can occur during their operation. Dry conditions and high temperatures can intensify the alkalinity within the AEM, potentially leading to accelerated degradation of organic cations.

[0004] Efforts have been made to stabilize organic cations. Stereoprotection strategies have been investigated, specifically how to enhance the stability of imidazolium cations. Other research approaches include using different configurations and stabilizing ammonium cations by controlling alkyl chain length.

[0005] Despite some progress, the known lifespan of AEMs remains too short for many commercial applications, especially those susceptible to low hydration conditions and high temperatures, such as those encountered in AEM fuel cells, which typically operate at 80°C and where water is consumed and removed from the cathode catalyst layer via electroosmosis. These low hydration conditions can be minimized by strictly controlling input humidity, limiting current density, and designing water-retaining membrane electrode assemblies, but these measures increase module cost and reduce performance.

[0006] Currently, several cations, namely N,N-dimethylpiperidin-1-onium (DMP), 1,3-dimethyl-2-mesotrimyl-4,5-diphenyl-1H-imidazol-3-onium (MMI), and benzyltrimethylammonium (BTMA), are used in commercial AEM. Most known hydroxide-stable organic cations are 6-azaspiro[5.5]undecane-6-onium (ASU), 1,3-dibutyl-2-mesotrimyl-4,5-diphenyl-1H-imidazol-3-onium (BMI), and tetra(cyclohexyl(methyl)amino)phosphonium (TCAP). Despite their high stability under alkaline conditions when fully hydrated, no known organic cation is considered to maintain sufficient stability over long periods in gas-phase AEM applications. Furthermore, there are no known stable organic cations with sufficiently low molecular weights to form materials with adequate charge carrier density, thereby enabling the fabrication of AEMs with high ion exchange capacity (IEC) and high ionic conductivity; BMI and TCAP are both relatively large cations with low mass-to-charge ratios, IECs of 2.13 meq / g and 2.01 meq / g, respectively, thus having low relevance to low-hydration applications.

[0007] The research of RW Alder et al. ( Inside- and outside-protonated ions from 1, 6-diazabicyclo[4.4.4]tetradecane The Journal of the American Chemical Society, 101, 3652–3653 (1978) disclosed 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium (in-DBD), a cationic structure with an intercalated proton. While Alder's research was groundbreaking, it became mired in complexity. The described process was highly complex, often requiring the use of hazardous chemicals, and lacked concrete experimental support for the claimed stability of the in-DBD. This made the method not only potentially dangerous but also challenging for large-scale production.

[0008] Therefore, the object of the present invention is to provide a new and improved method for producing commercially viable hydroxide-stable organic cationic structures suitable for electrochemical applications, including incorporating them into polymers and AEMs for alkaline environments. Summary of the Invention

[0009] According to a first aspect of this disclosure, a method for synthesizing 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium (in-DBD) is provided, comprising: i) oxidizing maleic hydrazine with 1,3-butadiene in the presence of 1,3-butadiene, or before mixing with 1,3-butadiene, to generate 1,6-diazabicyclo[4.4.0]dec-3,8-diene-2,5-dione; ii) hydrogenating 1,6-diazabicyclo[4.4.0]dec-3,8-diene-2,5-dione; iii) iv) The hydrogenated 1,6-diazabicyclo[4.4.0]dec-3,8-dien-2,5-dione is reduced with a reducing agent to generate 1,6-diazabicyclo[4.4.0]decane; iv) 1,6-diazabicyclo[4.4.0]decane is monoalkylated with a 1,4-substituted butane derivative having leaving groups at positions 1 and 4; v) The monoalkylated 1,6-diazabicyclo[4.4.0]decane is cyclized by addition to a metal salt to generate 1,6-diazatricyclo[4.4.4.0]tetrafluoroboronic acid. 1,6 Tetradecane-1,6-dimethylonium; vi) In an acidic medium, 1,6-diazatricyclo[4.4.4.0] is reduced with a reducing metal other than sodium. 1,6 The in-DBD is generated by annealing the N-N bond of tetradecane-1,6-dimethylonium to form an externally protonated DBD tetrafluoroborate; and vii) in an acidic medium, the externally protonated DBD tetrafluoroborate is internally protonated by oxidation with a single-electron oxidant to generate the in-DBD.

[0010] Step i) can be separated by extraction and recrystallized in a solvent selected from the group consisting of dichloromethane (DCM), toluene and diethyl ether.

[0011] The reducing agent in step iii) can be selected from the group consisting of LiAlH4, NaBH4, diisobutylaluminum hydride (DIBAL-H), and Et3SiH, or includes Wolff-Kishner reduction. The 1,4-substituted butane derivative in step iv) can be 1,4-dibromobutane, 1,4-diiodobutane, or 1,4-dichlorobutane. The 1,4-substituted butane derivative in step iv) can have a substituent at one or more positions at the 2- or 3-position of the butane chain. The reducing metal in step vi) can be selected from the group consisting of zinc, magnesium, and aluminum. The single-electron oxidant in step vii) can be peroxydisulfate, wherein the cation of the peroxydisulfate is selected from potassium (K... + ), sodium (Na + ), ammonium (NH4) + ) and lithium (Li +The solvent in step vii) can be tetrahydrofuran (THF). The metal salt in step v) can be silver tetrafluoroborate (AgBF4). The acidic medium in step vi) or vii) can contain tetrafluoroborate (HBF4). The acidic medium used in steps vi) and vii) can be the same acidic medium.

[0012] The externally protonated DBD tetrafluoroborate generated in step vi) is air-stable, and the reduction reaction in step vi) and the internal protonation reaction in step vii) can proceed continuously without separating the externally protonated DBD tetrafluoroborate.

[0013] According to another aspect of this disclosure, a method for integrating in-DBD into a polymer is provided. The method includes: i) polymerizing a bicyclohepten monomer containing a bromomethyl group in a first solvent using a vinyl addition polymerization catalyst to generate a brominated polymer; ii) reacting the brominated polymer with 1,6-diazabicyclo[4.4.0]decane in a second solvent to generate a polymer with a side-chain bicyclo[4.4.0]decyl group; iii) reacting the polymer with the side-chain bicyclo[4.4.0]decyl group with a silver salt in a third solvent, wherein the silver salt forms an insoluble salt with the bromomethyl group of the polymer; iv) reacting the product of step iii) with a reducing metal in an acidic solvent to generate a polymer with a side-chain reducing group; and v) reacting the polymer with the side-chain reducing group with an oxidant to generate a polymer containing an integrated in-DBD.

[0014] The vinyl addition polymerization catalyst can be selected from the group consisting of palladium catalysts, nickel catalysts, and combinations thereof, and wherein the first solvent in step i) is selected from the group consisting of toluene, dichloromethane, and ethers. The second solvent in step ii) can be selected from the group consisting of tetrahydrofuran, toluene, dichloromethane, and ethers. The silver salt in step iii) can be selected from the group consisting of silver tetrafluoroborate, silver nitrate, and silver fluoride, and the third solvent in step iii) is selected from the group consisting of tetrafluoroboric acid, water, and nitric acid. The reducing metal in step iv) can be selected from the group consisting of zinc, aluminum, and magnesium, and wherein the acid solvent in step iv) is selected from the group consisting of tetrafluoroboric acid, sulfuric acid, and hydrochloric acid. The oxidant in step v) can be a single-electron oxidant, and wherein the single-electron oxidant is peroxydisulfate, the cation of which is selected from potassium ions (K ions). + Sodium ions (Na) + ), ammonium ions (NH4) + ) and lithium ion (Li +In the group consisting of ), the brominated polymer in step i) can be poly[(5S,6S)-5,6-bis(bromomethyl)bicyclo[2.2.1]hept-2-ene], and the ratio of catalyst to monomer in step i) can be in the range of 1:50-1:50000.

[0015] According to another aspect of this disclosure, a method for integrating in-DBD into a polymer is provided. The method includes: i) reacting a bicyclohepten monomer containing a bromomethyl group with 1,6-diazabicyclo[4.4.0]decane in a first solvent to generate a first intermediate; ii) reacting the first intermediate with a silver salt in a second solvent to generate a second intermediate; iii) reacting the second intermediate with a reducing metal in an acidic solvent to generate a third intermediate; iv) reacting the third intermediate with an oxidizing agent to generate a fourth intermediate; and v) reacting the fourth intermediate with a vinyl addition polymerization catalyst in a third solvent to generate a polymer containing the integrated in-DBD.

[0016] The first solvent in step i) can be selected from the group consisting of tetrahydrofuran, toluene, dichloromethane, and ethers. The silver salt in step ii) can be selected from the group consisting of silver tetrafluoroborate, silver nitrate, and silver fluoride. The acid solvent in step iii) can be selected from the group consisting of tetrafluoroboric acid, sulfuric acid, and hydrochloric acid, and the reducing metal in step iii) can be selected from the group consisting of zinc, aluminum, and magnesium. The oxidant in step iv) can be potassium peroxydisulfate. The third solvent in step v) can be selected from the group consisting of toluene, dichloromethane, and ethers, and the vinyl addition polymerization catalyst in step v) can be selected from the group consisting of palladium catalysts and nickel catalysts. The ratio of catalyst to monomer in step v) can be in the range of 1:50 to 1:50000.

[0017] According to another aspect of this disclosure, an in-DBD polymer is provided, comprising: a polymer matrix; and a 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium (in-DBD) cationic structure integrated into the polymer matrix. The cationic charge of the in-DBD cationic structure is carried by fixed protons within an aliphatic cage formed by the three-dimensional structure of the in-DBD cationic structure and is stabilized between two nitrogen atoms of the in-DBD cationic structure by symmetrical intra-bridgehead hydrogen bonds.

[0018] The polymer matrix can be selected from the group consisting of: polysulfone, polyphenylene, polyaryletherketone, polyphenylene ether, polyethylene, polypropylene, polystyrene, polybenzimidazolium, and polynorbornene. The polymer matrix can be linked to the in-DBD cationic structure at multiple locations.

[0019] According to another aspect of this disclosure, an in-DBD polymer ion exchange membrane comprising the in-DBD polymer is provided.

[0020] According to another aspect of this disclosure, an in-DBD catalyst ink comprising a catalyst material, water, an organic solvent, and an in-DBD polymer is provided.

[0021] According to another aspect of this disclosure, an in-DBD catalyst coated membrane is provided, the membrane comprising a polymer ion exchange membrane coated with in-DBD catalyst ink, or an in-DBD polymer ion exchange membrane coated with conventional catalyst ink or in-DBD catalyst ink.

[0022] According to another aspect of this disclosure, a membrane electrode assembly is provided, comprising an anode layer, a cathode layer, and an in-DBD polymer ion exchange membrane.

[0023] According to another aspect of this disclosure, a fuel cell is provided that includes at least one of the in-DBD polymer ion exchange membrane, the in-DBD catalyst ink, and the in-DBD catalyst coating membrane.

[0024] According to another aspect of this disclosure, an electrolyzer is provided that includes at least one of the in-DBD polymer ion exchange membrane, the in-DBD catalyst ink, and the in-DBD catalyst coating membrane.

[0025] According to another aspect of this disclosure, the use of in-DBD as a cationic functional group for the preparation of anion exchange membranes (AEMs) is provided, wherein the cationic charge of the in-DBD is carried by fixed protons within an aliphatic cage formed by the three-dimensional structure of the in-DBD and is stabilized between two nitrogen atoms of the in-DBD by symmetrical intrabridge hydrogen bonds.

[0026] The scope of this invention is not necessarily all-encompassing. Other aspects, features, and advantages will become clear to those skilled in the art upon review of the following detailed description. Attached Figure Description

[0027] The accompanying drawings illustrate one or more exemplary embodiments:

[0028] Figure 1 The illustration shows 1,6-diazabicyclo[4.4.0]dec-3,8-diene-2,5-dione in CDCl3. 1 H nuclear magnetic resonance (NMR) spectrum.

[0029] Figure 2The figure illustrates the presence of 1,6-diazabicyclo[4.4.0]decane-2,5-dione in CDCl3. 1 ¹H NMR spectrum. The residual dichloromethane solvent signal is represented as CH₂Cl₂.

[0030] Figure 3 The diagram illustrates the role of 1,6-diaza-1-(4-bromobutyl)bicyclo[4.4.0]decane-1-bromium in D2O. 1 H NMR spectrum.

[0031] Figure 4 The diagram illustrates 1,6-diazatricyclic [4.4.4.0]. 1,6 Tetradecane-1,6-dimethylonium tetrafluoroborate in D2O 1 H NMR spectrum.

[0032] Figure 5 The diagram illustrates the reaction of 1,6-diazabicyclo[4.4.4]tetradecane-1-onium tetrafluoroborate in D2O. 1 1H NMR spectrum. The residual diethyl ether solvent signal is represented by Et₂O.

[0033] Figure 6 The diagram illustrates the presence of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium[intrinsic]tetrafluoroborate in D2O. 1 1H NMR spectra. The residual diethyl ether and methanol solvent signals are represented by Et2O and CH3OH, respectively.

[0034] Figure 7 The diagram illustrates the presence of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium[intrinsic]tetrafluoroborate in D2O. 13 C NMR spectrum.

[0035] Figure 8 The diagram illustrates the presence of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium[intrinsic]tetrafluoroborate in D2O. 19 F NMR spectrum.

[0036] Figure 9 The diagram illustrates the role of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium chloride [inner proton] in CD3OD. 1 H NMR spectrum.

[0037] Figure 10 The diagram illustrates the role of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium chloride [inner proton] in CD3OD. 13 C NMR spectrum.

[0038] Figure 11 The diagram illustrates the role of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium chloride [inner proton] in CD3OD. 19 F NMR spectrum.

[0039] Figure 12 The figure illustrates the thermogravimetric analysis of in-DBD Cl under a nitrogen atmosphere at a heating rate of 10 °C / min. The gray line represents 95% of the original mass, which defines the decomposition temperature as approximately 388 °C.

[0040] Figure 13 The figures illustrate the NMR spectral degradation studies of the organic cations. (A) Percentage of remaining cations relative to time as measured by NaDSS internal standard. These lines are for visual guidance. (B) Estimated cation half-life based on decomposition rate. Decomposition studies were conducted in anhydrous CD3OD containing 2 M KOH, 0.03 M analyte, and 0.03 M NaDSS internal standard.

[0041] Figure 14 The figure illustrates BTMA on day 0 of the NMR degradation experiment. 1 H NMR spectrum. Circles represent the proton signal of BTMA, while squares represent the proton signal of NaDSS internal standard.

[0042] Figure 15 The figure illustrates the experimental blank sample; the superposition of 2 M KOH (CD3OD) containing the internal standard of sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M). 1 ¹H NMR spectra. The NMR tube was heated to 80°C between samples and cooled before obtaining the next spectrum. The peak near 1.2 ppm was an impurity found in all commercial KOH and NaOH sources (multiple batches and suppliers) tested, and its variation was not observed during the experiment and did not appear to interfere with this study.

[0043] Figure 16 The figure illustrates the superposition of benzyltrimethylammonium chloride (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR spectra. The NMR tube was heated to 80°C between samples and then cooled before obtaining the next spectrum.

[0044] Figure 17 The figure illustrates the magnified superposition of benzyltrimethylammonium chloride (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 11H NMR spectra. The NMR tube was heated to 80°C between samples and then cooled before obtaining the next spectrum.

[0045] Figure 18 The figure illustrates the effects of benzyltrimethylammonium chloride (0.03 M) on day 29 in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR spectra. The NMR tube was heated to 80°C for 29 days. The overlay shows the remaining analyte peaks (circles) and degradation product peaks (squares).

[0046] Figure 19 The figure illustrates the superposition of 1,3-dimethyl-2-trimethylmethyl-4,5-diphenyl-1H-imidazolium-3-iodide (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR spectra. The NMR tube was heated to 80°C between samples and then cooled before obtaining the next spectrum.

[0047] Figure 20 The figure illustrates the magnified superposition of 1,3-dimethyl-2-trimethylmethyl-4,5-diphenyl-1H-imidazolium-3-iodide (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR spectra. The NMR tube was heated to 80°C between samples and then cooled before obtaining the next spectrum.

[0048] Figure 21 The figure illustrates the effects of 1,3-dimethyl-2-trimethylmethyl-4,5-diphenyl-1H-imidazolium-3-iodide (0.03 M) on day 29 in 2 MKOH (CD3OD) containing the internal standard of sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M). 1 1H NMR spectrum. The NMR tube was heated to 80°C for 29 days. The overlay shows the remaining analyte peaks (circles) and degradation product peaks (squares).

[0049] Figure 22 The figure illustrates the superposition of 1,1-dimethylpiperidinium iodide (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR spectra. The NMR tube was heated to 80°C between samples and then cooled before obtaining the next spectrum.

[0050] Figure 23 The figure illustrates the magnified superposition of 1,1-dimethylpiperidinium iodide (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR spectra. The NMR tube was heated to 80°C between samples and then cooled before obtaining the next spectrum. Increased intensity in the region within the frame indicates the formation of a small amount of elimination products.

[0051] Figure 24 The figure illustrates the effects of 1,1-dimethylpiperidinium iodide (0.03 M) on day 30 in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR spectrum. The NMR tube was heated to 80°C for 30 days. The overlay shows the remaining analyte peaks (circles) and degradation product peaks (squares).

[0052] Figure 25 The figure illustrates the superposition of 6-azaspiro[5.5]undecane-6-bromide (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR spectra. The NMR tube was heated to 80°C between samples and then cooled before obtaining the next spectrum.

[0053] Figure 26 The figure illustrates the magnified superposition of 6-azaspiro[5.5]undecane-6-bromoonium (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR spectra. The NMR tube was heated to 80°C between samples and then cooled before obtaining the next spectrum.

[0054] Figure 27 The figure illustrates day 29 of 6-azaspiro[5.5]undecane-6-bromoonium (0.03 M) in 2 MKOH (CD3OD) containing the internal standard sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M). 1 1H NMR spectra. The NMR tube was heated to 80°C for 29 days. The overlay shows the remaining analyte peaks (circles) and degradation product peaks (squares).

[0055] Figure 28The figure illustrates the superposition of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-chloroonium chloride [inner proton] (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR spectra. The NMR tube was heated to 80°C between samples and then cooled before obtaining the next spectrum.

[0056] Figure 29 The figure illustrates the magnified superposition of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-chloroonium chloride [inner proton] (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 HNMR spectra. The NMR tube was heated to 80°C between samples and then cooled before obtaining the next spectrum.

[0057] Figure 30 The figure illustrates day 29 of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-chlorotonium (inner proton) (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 HNMR spectra. The NMR tube was heated to 80°C for 29 days. The overlay shows the remaining analyte peaks (circles), while the degradation product peaks were not observed and therefore cannot be highlighted.

[0058] Figure 31 The figure illustrates the superposition of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium[intrinon]tetrafluoroborate (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR spectrum. The NMR tube was heated to 80°C between samples and then cooled before obtaining the next spectrum.

[0059] Figure 32 The figure illustrates the magnified superposition of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium[intrinon]tetrafluoroborate (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR spectra. The NMR tube was heated to 80°C between samples and then cooled before obtaining the next spectrum. Increased intensity in the areas within the frame indicates regions where degradation products should have been eliminated.

[0060] Figure 33The diagram illustrates the percentage of residual cations in in-DBD relative to its chloride and BF4 content. – Ionic form.

[0061] Figure 34 The figure illustrates the superposition of (A) sodium tetrafluoroborate (molar concentration) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (molar concentration) as an internal standard. 19 F NMR spectra. The NMR tube was heated to 80°C between samples and then cooled before obtaining the next spectrum. (B) Integral ratio of the BF3(OH) degradation product signal to the BF4 signal.

[0062] Figure 35 The figure illustrates the NMR stability of the residual cation of benzyltrimethylammonium chloride (0.03 M) in 2 MKOH (CD3OD) with sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard over time. The black line represents the linear fit of data collected in the first 10 days.

[0063] Figure 36 The figure illustrates the NMR stability of the residual cation of 1,3-dimethyl-2-trimethylmethyl-4,5-diphenyl-1H-imidazolium-3-iodide (0.03 M) in 2 MKOH (CD3OD) with the internal standard of sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as a function of time. The black line represents a linear fit of the collected data.

[0064] Figure 37 The figure illustrates the NMR stability of the residual cation of 1,1-dimethylpiperidinium iodide (0.03 M) in 2 MKOH (CD3OD) with the internal standard of sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) over time. The black line represents a linear fit of the collected data.

[0065] Figure 38 The figure illustrates the NMR stability of the residual cation of 6-azaspiro[5.5]undecane-6-bromide (0.03 M) in 2 MKOH (CD3OD) with the internal standard of sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as a function of time. The black line represents the linear fit of the collected data.

[0066] Figure 39The figure illustrates the NMR stability of the residual cation of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-chloroonium[inner proton] (0.03 M) in 2 MKOH (CD3OD) with sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard over time. The black line represents a linear fit of the collected data.

[0067] Figure 40 The figure illustrates the dynamic vapor adsorption (DVS) degradation study of cation-hydroxides. The DVS mass changes over time for (A) in-DBD OH, (B) DMP OH, (C) ASU OH, and (D) MMI OH as RH is reduced. All experiments were conducted at 80 °C.

[0068] Figure 41 The figure illustrates the DVS stability test of the fully volatile cationic hydroxide. (A) Normalized mass loss over time. (B) Extraction half-life of the cation at 11% RH and 80°C.

[0069] Figure 42 The figures illustrate (A) the change of raw relative humidity over time in the DVS study and (B) the last 30 minutes of each new (or reference) RH.

[0070] Figure 43 The figure illustrates the DVS analysis of in-DBD hydroxides at reduced relative humidity levels. The temperature was maintained at 80°C throughout the experiment. The gray line corresponds to the gray axis on the left; the black dashed line corresponds to the black axis on the right.

[0071] Figure 44 The figure illustrates the superposition of in-DBD hydroxides before and after the DVS experiment. 1 H NMR spectra. The “pre-DVS” sample is a hydroxide-exchanged cation and can be carbonized in open air for several days before the solvent is removed to obtain NMR spectra.

[0072] Figure 45 The figure illustrates the DVS analysis of DMP hydroxide at reduced relative humidity levels. The temperature was maintained at 80°C throughout the experiment. The gray line corresponds to the left gray axis; the black dashed line corresponds to the right black axis.

[0073] Figure 46 The figure illustrates the superposition of DMP hydroxide before and after the DVS experiment. 1 H NMR spectrum. The “pre-DVS” sample is a hydroxide-exchanged cation and can be carbonized in open air for several days before the solvent is removed to obtain the NMR spectrum.

[0074] Figure 47The figure illustrates the DVS analysis of ASU hydroxide at reduced relative humidity levels. The temperature was maintained at 80°C throughout the experiment. The gray line corresponds to the left gray axis; the black dashed line corresponds to the right black axis.

[0075] Figure 48 The figure illustrates the superposition of ASU hydroxide before and after the DVS experiment. 1 H NMR spectrum. The “pre-DVS” sample is a hydroxide-exchanged cation and can be carbonized in open air for several days before the solvent is removed to obtain the NMR spectrum.

[0076] Figure 49 The figure illustrates the DVS analysis of MMI hydroxides at reduced relative humidity levels. The temperature was maintained at 80°C throughout the experiment. The gray line corresponds to the left gray axis; the black dashed line corresponds to the right black axis.

[0077] Figure 50 The figure illustrates the superposition of MMI hydroxides before and after the DVS experiment. 1 H NMR spectrum. The “pre-DVS” sample is a hydroxide-exchanged cation and can be carbonized in open air for several days before the solvent is removed to obtain the NMR spectrum.

[0078] Figure 51 The diagram illustrates the superposition of four cationic hydroxides that were permissible for carbonation after their respective DVS experiments. 1 1H NMR spectrum. The arrows point to common impurities / artifacts generated in the experiment rather than from degradation products.

[0079] Figure 52 The figure illustrates the initial and significant degradation of cation-hydroxide extracts as determined by DVS experiments at 80°C. The estimated λ level (defined as the water-to-hydroxide ratio) was obtained from the in-DBD hydroxide isotherm shown below. Light bars indicate RH at which no degradation was observed; dashed lines indicate areas where mass loss exceeded 0.4% but was less than 2% per hour at a specified RH; dark bars indicate RH at which mass loss exceeded 2% per hour. Horizontal boxes represent the defined critical conditions from 30% to 10% RH.

[0080] Figure 53 The figures illustrate (A) DVS analysis of in-DBD hydroxides at 60°C and reduced relative humidity levels. (B) Plotting the last 30 minutes of each RH step. The two gray areas represent RH conditions of 30%–10% and 10%–0%, respectively. Shaded areas indicate RH at which degradation occurred, while the adjacent numbers indicate the first RH at which significant degradation was observed. The gray lines correspond to the left gray axis, while the black dashed lines correspond to the right black axis.

[0081] Figure 54 The figures illustrate (A) humidity isotherms of in-DBD hydroxides at 60°C and 80°C, with hydration numbers estimated from the slope to 0% RH. (B) humidity isotherms of four cation-hydroxides studied using their original mass relative to relative humidity (since the stability of all ions except in-DBD is insufficient to estimate mass at 0% RH).

[0082] Figure 55 The figure illustrates the DVS control analysis of MMI iodides at reduced relative humidity levels. The temperature was maintained at 80°C throughout the experiment. The gray line corresponds to the left gray axis, and the black dashed line corresponds to the right black axis.

[0083] Figure 56 The figure illustrates the superposition of MMI iodides before and after the DVS experiment. 1 H NMR spectrum. The experimental airflow removed a small amount of residual DMSO and indicated a small mass loss.

[0084] Figure 57 The figures illustrate the DVS mass trace of ASU hydroxide over time at 80°C. (A) Experimental mass and RH trace during the experiment, and (B) Mass and RH trace of the data measured after RH stabilization for each measurement. The dashed line represents the reference (stabilized) 55% RH before degradation, and the dotted dashed line represents the initial mass at the test 11% RH. The gray line corresponds to the gray axis on the left; the black dashed line corresponds to the black axis on the right.

[0085] Figure 58 The figure illustrates the DVS mass trace of DMP hydroxide relative to time at 80°C. (A) Experimental mass and RH trace during the experiment, (B) Mass and RH trace of the data after each measurement has stabilized at RH. The dashed line represents the reference (stable) 55% RH before degradation, and the dotted dashed line represents the initial mass at 11% RH during the test. The gray line corresponds to the gray axis on the left, and the black dashed line corresponds to the black axis on the right.

[0086] Figure 59 The figures illustrate the DVS mass trace of in-DBD hydroxides relative to time at 80°C. (A) Experimental mass and RH trace during the experiment, and (B) Mass and RH trace of the data after each measurement has stabilized at RH. The dashed line represents the reference (stable) 55% RH before degradation, and the dotted dashed line represents the initial mass at 11% RH during the test. The gray line corresponds to the gray axis on the left, and the black dashed line corresponds to the black axis on the right.

[0087] Figure 60The figure illustrates the DVS out-gas of in-DBD collected after complete degradation in a 5% v / v acetic acid solution. 1 1H NMR spectrum. Only identified product protons are labeled; the poor integrated quality is presumably due to tautomerism of protonated nitrogen and / or inversion of the nitrogen center, resulting in multiple chemical environments. The circle at 17 ppm is used to emphasize the lack of caged protons in the degradation products, indicating complete degradation.

[0088] Figure 61 The figure illustrates the DVS escaping gas of in-DBD collected after complete degradation in a 5% v / v acetic acid solution. 13 C10 NMR spectrum. Only the carbon atoms of the identified products are labeled.

[0089] Figure 62 The figure illustrates the positive ion mass spectrum of the DVS escape gas of in-DBD collected after complete degradation in a 5% v / v acetic acid solution. Only the identified products are shown, with their theoretical m / z indicated.

[0090] Figure 63 The diagram illustrates the DFT calculation results for the cation. (A) LUMO isosurface of in-DBD and (B) electrostatic potential (ESP) of in-DBD. ESP is expressed in Hartree atomic units, where a larger positive number indicates a stronger positive potential and higher electrophilicity. (C) Free energy difference between the parent cation and degradation products, calculated in an aqueous continuous medium model. Degradation products not observed in the experiment are indicated by dashed lines. (D) Energy barrier required to deprotonate the caged protons of in-DBD. The structure shows OH Approximately the caged protons. DFT calculations were performed at the theoretical level of ωB97XD / 6-31g(dp).

[0091] Figure 64 The figure illustrates the calculated orbital isosurfaces for HOMO and LUMO in-DBD. Calculations were performed at the theoretical level of ωB97XD / 6-31g(dp).

[0092] Figure 65 The illustrations show the generation energy calculations for the relative energies of external protonation versus internal protonation in in-DBD (left two images) and typical proton sponges (right two images). Calculations are performed at the theoretical level of ωB97XD / 6-31g(dp). Detailed Implementation

[0093] The embodiments disclosed herein generally relate to novel methods for synthesizing in-DBD cationic structures and incorporating said in-DBD cationic structures into polymers for use in electrochemical applications such as anion exchange membranes (AEMs), catalyst inks, catalyst-coated membranes, fuel cells, water electrolyzers, and carbon dioxide and / or carbon monoxide electrolyzers. The in-DBD cationic structure allows the cationic charge to be carried by a proton stable within an aliphatic cage formed by its three-dimensional structure and anchored between two nitrogen atoms via symmetrical bridgehead hydrogen bonds. Through the synthetic method of in-DBD and its application in various electrochemical applications, an organic cationic hydroxide has been achieved that remains stable at extremely low hydration levels and high temperatures (80°C, RH < 10%), exhibiting several orders of magnitude higher hydroxide stability than conventional cations.

[0094] Utilizing innovative chemical pathways and novel synthetic techniques, this new in-DBD synthesis method emphasizes safety, reproducibility, and scalability. Specifically, this embodiment introduces a refined workshop operation procedure that not only enhances scalability but also improves safety by eliminating the use of hazardous solvents such as benzene and carbon tetrachloride. This workshop operation procedure also avoids time-consuming distillation, instead simply filtering and concentrating the reaction mixture, thereby reducing associated purification costs and enhancing scalability. The resulting in-DBD cationic structure, characterized by higher yield and consistent quality, represents a significant advancement compared to existing techniques for synthesizing in-DBD structures and provides unprecedented or direct new opportunities for integrating in-DBD cationic structures into polymers for electrochemical applications.

[0095] Synthesis of in-DBD According to some embodiments, a method for synthesizing in-DBD cationic structures includes the following steps: Step 1: Maleic amide is oxidized with 1,3-butadiene in the presence of or before mixing with 1,3-butadiene. Hydrazine, to form 1,6-diazabicyclo[4.4.0]dec-3,8-diene-2,5-dione

[0096] To initiate the synthesis, maleic hydrazide is mixed with 1,3-butadiene in a suitable solvent selected from the group of solvents that do not react with the oxidant or otherwise affect the reaction, including but not limited to dichloromethane (DCM), toluene, and various ethers (such as diethyl ether), but excluding polar aprotic solvents (DMSO, DMF, acetone) that react with lead acetate, alcohol solvents, and water.

[0097] An oxidizing agent is introduced to assist the reaction, more specifically, for the oxidation of maleic hydrazide, to produce a favorable dienophile, thereby reacting any diene (butadiene, isoprene, etc.) to generate the key structure and, in any case, the functional groups on the diene. The oxidizing agent can be selected from reagents such as lead tetraacetate (Pb(OAc)4), other metal-based oxidants, organic peroxides, or any other established oxidizing compound. The proposed mechanism for the oxidizing agent is concerted 2-electron oxidation; however, similar oxidation processes exist in the presence of a base, which can proceed via two single-electron oxidants.

[0098] Depending on the specific reactants and oxidants used, the reaction temperature range can be from as low as approximately -78°C to room temperature or even higher. After mixing the components, allow them to react until the desired conversion is achieved, monitoring the reaction progress using various techniques such as colorimetric assays, spectroscopy, or other relevant analytical methods. Once the reaction is complete, it can be quenched using a suitable reagent (e.g., water or a dilute aqueous solution). Subsequently, the target product, 1,6-diazabicyclo[4.4.0]dec-3,8-dien-2,5-dione, is separated and purified using standard separation methods such as extraction, filtration, or chromatography. The isolated compound can be further confirmed and characterized using common analytical techniques, including but not limited to nuclear magnetic resonance (NMR), mass spectrometry, and infrared spectroscopy.

[0099] Please note that existing methods for step 1 typically require a post-treatment process in carbon tetrachloride using alumina gel column chromatography, followed by recrystallization in benzene, both of which present significant safety and environmental concerns. This invention significantly mitigates these issues by introducing an improved post-treatment process that requires only extraction, followed by direct recrystallization in a non-toxic solvent such as diethyl ether. This improvement not only enhances scalability by avoiding column chromatography but also raises safety standards by eliminating the use of hazardous solvents such as benzene and carbon tetrachloride.

[0100] For clarity, the specific components mentioned in the chemical reactions, including Pb(OAc)4 and DCM, are used only as exemplary examples. They are not intended to limit or restrict the scope of this disclosure in any way.

[0101] Step 2: Hydrogenation of 1,6-diazabicyclo[4.4.0]dec-3,8-diene-2,5-dione

[0102] 1,6-diazabicyclo[4.4.0]dec-3,8-diene-2,5-dione is mixed with a suitable hydrogenation catalyst, which can be selected from, but is not limited to, the group consisting of palladium, platinum and nickel. Those skilled in the art will understand that this reaction is a simple olefin hydrogenation reaction and that many suitable catalysts are available, including carbon-supported palladium and Raney nickel (nickel nanoparticles).

[0103] The catalyst can be supported on a carbon matrix or left unsupported. It is advantageous to carry out the reaction in a solvent selected from, but not limited to, the group consisting of water, ethyl acetate, alcohols, and ethers. However, any solvent capable of dissolving the reagent and not subject to hydrogenation is expected to be usable.

[0104] Hydrogen is introduced into the mixture under normal or high pressure to promote the reaction. The reaction temperature can be varied, ranging from about 0°C to ambient temperature or even higher, depending on the selected hydrogen pressure and catalyst. The reaction progress can be monitored using various techniques, such as colorimetry, spectroscopy, or other suitable analytical methods.

[0105] Once the reaction is complete, the catalyst can be separated using techniques known in the art, such as filtration or decantation. This separation can be performed after quenching with a suitable reagent, or it can be performed without quenching. Subsequently, the target product 1,6-diazabicyclo[4.4.0]decane-2,5-dione is separated and purified using conventional separation techniques, such as extraction, filtration, or chromatography.

[0106] The obtained product can be further characterized using conventional analytical methods, including but not limited to NMR, mass spectrometry, or infrared spectroscopy. Note that a post-processing step has been uniquely developed and proposed in this step, as it has not been previously reported.

[0107] For clarity, the specific components mentioned in the chemical reactions, including Pd / C, H2, and H2O, are used only as exemplary examples. They are not intended to limit or restrict the scope of this disclosure in any way.

[0108] Step 3: 1,6-diazabicyclo[4.4.0]dec-2,5-dione was reduced with a reducing agent to produce 1,6-diazabicyclo[4.4.0]dec-2,5-dione. [4.4.0] Decane

[0109] Hydrogenated 1,6-diazabicyclo[4.4.0]dec-3,8-dien-2,5-dione can be reduced using a suitable reducing agent such as lithium aluminum hydride (LiAlH4). LiAlH4 is a strong hydride reducing agent that chelates with oxygen, further reducing the alcohol group. Other reducing agents suitable for this reaction are generally known to those skilled in the art, including sodium borohydride or hydride for partial reduction, and another Lewis acid for complete reduction of the group. Other methods for reducing ketones, such as Wolff-Kishner reduction, can also be used, provided that the reaction can be carried out in a solvent in which the product can be easily recovered, and that the next reaction can be carried out directly in the same solvent (without separation).

[0110] In this embodiment, 1,6-diazabicyclo[4.4.0]decane-2,5-dione is mixed with a solvent suitable for LiAlH4 reduction, including, but not limited to, ethers such as tetrahydrofuran (THF), diethyl ether, dimethoxyethane, dioxane, and dibutyl ether. A suitable metal hydride reducing agent is added to the mixture. The range of reducing agents can include lithium aluminum hydride, other metal hydrides, or any other hydride reducing agent recognized in the art. The solvent used can be an anhydrous solvent, and oxygen is removed by using an inert gas such as nitrogen or argon. The reaction temperature can be varied from room temperature to the reflux temperature of the selected solvent.

[0111] The progress of the reaction can be monitored using various techniques such as colorimetry, spectrometry, or other suitable analytical methods. Once the reaction is complete, the mixture can be quenched using a suitable reagent, including water or dilute acid. Subsequently, the target product, 1,6-diazabicyclo[4.4.0]decane, can be separated and purified by conventional methods such as extraction, filtration, and chromatography, or can be used directly in subsequent reactions without further purification. The final product can then be evaluated using standard analytical tools, including but not limited to NMR, mass spectrometry, or infrared spectroscopy.

[0112] Please note that, unlike previous literature which required product distillation (a time-consuming and energy-intensive process), this disclosure introduces a post-processing step that circumvents this requirement. Instead, the reaction mixture can be readily used for the next step after simple filtration and concentration, thereby reducing associated purification costs and improving scalability.

[0113] For clarity, specific components mentioned in the chemical reactions, including LiAlH4 and THF, are used only as exemplary examples. They are not intended to limit or restrict the scope of this disclosure in any way.

[0114] Step 4: In solvents, 1,4-substituted butane derivatives with leaving groups at positions 1 and 4 were used to counteract 1,6-diazaphosphine. Monoalkylation of bicyclo[4.4.0]decane

[0115] 1,6-diazabicyclo[4.4.0]decane is mixed with a suitable solvent that does not react with any reagent, including alkylating solvents such as tetrahydrofuran, dichloromethane, and acetonitrile. However, it should be noted that the reaction can also be carried out without the use of a solvent. Furthermore, other polar aprotic solvents such as dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) can also be used.

[0116] A butane derivative is added to the mixture, wherein the butane derivative has functional groups at positions 1 and 4 as effective leaving groups. The butane derivative may also contain different functional groups at positions 2 and 3. The effective leaving group can include, but is not limited to, halogens, toluenesulfonyl groups, or methanesulfonyl groups. In this embodiment, 1,4-dibromobutane is used. Alternatively, 1,4-diiodobutane or 1,4-dichlorobutane can also be used. The reaction temperature range can be from room temperature to the solvent reflux temperature, or even above the reflux temperature when carried out in a sealed apparatus. The reaction progress can be monitored using various techniques, including colorimetry, spectrometry, or other relevant analytical methods.

[0117] Once the reaction is complete, the target compound, referred to in this embodiment as 1,6-diaza-1-(4-bromobutyl)bicyclo[4.4.0]decane-1-onium, can be separated and purified using standard separation methods such as extraction, filtration, or chromatography. The specific counterion associated with the product, such as the bromide ion, can vary based on the selected leaving group. The final compound can be characterized using conventional analytical methods such as NMR, mass spectrometry, or infrared spectroscopy.

[0118] It is worth noting that previous literature typically describes the use of pure 1,4-dibromobutane and the reaction being carried out in significant excess. This disclosure illustrates a method that reduces the amount of 1,4-dibromobutane used and allows the reaction to proceed within the previously prepared reaction mixture. Such modifications have the potential to reduce reagent-related costs and streamline purification processes. Furthermore, processing directly from the product of step 3, without intermediate separation, improves scalability.

[0119] For clarity, the specific components mentioned in the chemical reactions, including 1,4-dibromobutane and THF, are used only as exemplary examples. They are not intended to limit or restrict the scope of this disclosure in any way.

[0120] Step 5: The monoalkylated 1,6-diazabicyclo[4.4.0]decane was cyclized by adding it to a metal salt. 1,6-diazatricyclic ring [4.4.4.0] is generated. 1,6 Tetradecane-1,6-dimethylonium tetrafluoroborate

[0121] 1,6-diaza-1-(4-bromobutyl)bicyclo[4.4.0]decane-1-bromium is reacted with a suitable silver salt in a selected solvent. The suitable silver salt is water-soluble and reacts with a halogen (bromine in this example) to form an insoluble silver halide. The selected silver salt is soluble in the solvent and forms an insoluble compound when paired with a leaving group of the reactant. Simultaneously, the solvent should be able to dissolve both the silver salt and the reactant. Potential candidates for the silver salt include silver tetrafluoroborate, silver nitrate, and silver fluoride. The salt can be generated in situ or introduced separately. Possible solvents for this reaction range from tetrafluoroborate, water, and nitric acid to various ethers. The reaction temperature is flexible and can be within the range of ambient temperature to solvent reflux temperature. The progress of the reaction can be continuously monitored by methods such as colorimetric analysis, spectroscopy, or other established analytical techniques.

[0122] Once the reaction is complete, conventional separation methods, including extraction, filtration, or chromatography, can be used to separate and purify the 1,6-diazatricyclic ring identified in this embodiment [4.4.4.0]. 1,6 The target compound was tetradecane-1,6-dimethylonium tetrafluoroborate. It should be noted that the specific counterion, such as tetrafluoroborate, is not a key factor determining the success of the reaction. Subsequent characterization of the final compound was possible using mainstream analytical tools, including NMR, mass spectrometry, and infrared spectroscopy.

[0123] For clarity, the specific components mentioned in the chemical reactions, including Ag2O and HBF4, are used only as exemplary examples. They are not intended to limit or restrict the scope of this disclosure in any way.

[0124] Step 6: 1,6-diazatricyclo[4.4.4.0] was reduced in an acidic medium with a reducing metal other than sodium. 1,6 ] The externally protonated DBD tetrafluoroborate is formed by the N / N bond of tetradecane-1,6-dimethylonium.

[0125] In the aforementioned process, 1,6-diazatricyclo[4.4.4.0] is used. 1,6Tetradecane-1,6-dimethylonium tetrafluoroborate is reacted with a suitable reducing metal in a strong acid solvent. In one embodiment, the pH of the acid solvent is equal to or less than 1. In another embodiment, the acid solvent can be a strong acid known in the art that is fully or nearly fully ionized, such as HCl, H₂SO₄, HNO₃, HBr, and HBF₄. Possible solvents include tetrafluoroboric acid, sulfuric acid, and hydrochloric acid. Suitable reducing metals (excluding sodium, due to its reactivity with water) include, but are not limited to, aluminum, magnesium, and zinc, all of which provide single-electron reduction products to form salts. The reaction temperature is flexible, ranging from ambient temperature to the reflux temperature of the solvent. The reaction progress can be tracked by established methods such as colorimetric analysis, spectrometry, or other analytical techniques. Once the reaction is complete, the target compound identified in this embodiment as 1,6-diazabicyclo[4.4.4]tetradecane-1-onium[exproton]tetrafluoroborate can be separated and purified using conventional separation methods, including extraction, filtration, or chromatography, or proceeded to subsequent reactions without intermediate purification. It can use common analytical tools, including NMR, mass spectrometry, and infrared spectroscopy, to perform the final characterization of the compound.

[0126] This step is a variant with advantages over previous methods. Since previous techniques involved Birch reduction conditions using liquid ammonia and metallic sodium (a combination that presents potential safety hazards), this method offers an advantageous approach. Reduction is performed in an acidic medium using metals such as zinc, with tetrafluoroboric acid being a suitable choice. However, it is worth noting that other metals such as magnesium and aluminum may also be effective, and other acids may also be applicable. Due to the poor air stability of the uncharged products, conventional post-processing methods require separation by sublimation in an airless environment; this method has improved upon this. The strategy of this invention separates the intermediate as an exoprotonated salt, which demonstrates air stability. These improvements provide a safer, more scalable method with the potential additional benefit of reduced associated costs. Furthermore, the possibility of eliminating the need for prior product separation for subsequent reactions further enhances scalability and cost-effectiveness.

[0127] For clarity, the specific components mentioned in the chemical reactions, including Zn and HBF4, are used only as exemplary examples. They are not intended to limit or restrict the scope of this disclosure in any way.

[0128] Step 7: In an acidic medium, the externally protonated DBD tetrafluoroborate is oxidized by a single-electron oxidant to achieve internal oxidation. Protonation generates in-DBD

[0129] In this embodiment, 1,6-diazabicyclo[4.4.4]tetradecane-1-onium[exproton]tetrafluoroborate reacts with a suitable oxidant in a strong acid solvent. In one embodiment, the acid solvent may have a pH value equal to or less than 1. In another embodiment, the acid solvent may be a fully or nearly fully ionized strong acid known in the art, such as HCl, H₂SO₄, HNO₃, HBr, and HBF₄. Solvents include tetrafluoroboric acid, sulfuric acid, and hydrochloric acid, etc. Suitable oxidants include potassium peroxydisulfate, and those skilled in the art should understand that the mechanism of any peroxide is essentially the same, and various peroxides that are single-electron oxidants and sufficiently stable in contact with acids without exploding are also applicable, such as benzoyl peroxide and other organic peroxides.

[0130] The reaction temperature is variable, ranging from ambient conditions to the reflux temperature of the solvent. Established techniques such as colorimetry, spectrometry, or other relevant analytical methods can be used to track the completion of the reaction. After the reaction, the target compound identified in this example as 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium[internal]tetrafluoroborate can be separated and purified by conventional methods such as extraction, filtration, or chromatography. The resulting product can be comprehensively characterized using common analytical tools, including NMR, mass spectrometry, and infrared spectroscopy.

[0131] This step presents a variant with advantages over conventional methods. Existing literature lacks sufficient detail regarding the reproducibility of the target molecule and comprehensive characterization data for the compound. The method of this invention establishes new reaction conditions for the synthesis of the target molecule and provides a complete set of characterization methods to ensure the formation of specific in-DBD compounds. Another advantage introduced by the method of this invention is the ability to proceed directly from the preceding reaction mixture to this step without intermediate purification. This direct approach improves scalability and reduces the potential costs of purification processes.

[0132] For clarity, the specific components mentioned in the chemical reactions, including K2S2O8 and HBF4, are used only as exemplary examples. They are not intended to limit or restrict the scope of this disclosure in any way.

[0133] Polymer structures containing in-DBD As shown below, the structure of the in-DBD molecule is defined as R6 acting as a multifunctional functional group, ranging from simple hydrogen atoms to complex polymer structures.

[0134]

[0135] R6 is unique in its adaptability. Specifically, R6 has the potential to become a hydrogen atom, any functional group known in the field of organic chemistry, or a polymer fragment. When R6 is embodied in a polymer structure, it opens up numerous possibilities for integrating in-DBD molecules into a wide variety of polymer matrices (hereinafter referred to as "in-DBD polymers"). This adaptability paves the way for the development of materials with tailored properties suitable for specific applications.

[0136] For example, common polymers compatible with electrochemical applications such as AEM can include, but are not limited to: polysulfone, polyphenylene, polyaryletherketone, polyphenylene ether, polyethylene, polypropylene, polystyrene, polybenzimidazolium, and polynorbornene. The introduction of the in-DBD cationic structure into these polymers can be achieved in a variety of configurations. For instance, R6 can be linked to the polymer matrix at a single point or multiple links can be established throughout the polymer structure, thereby enhancing the distribution of the in-DBD molecules in the matrix.

[0137] Furthermore, the connection between the in-DBD molecules and the polymer matrix can be diverse. The in-DBD structure can be directly integrated into the polymer backbone to ensure seamless compatibility. Alternatively, it can be connected through various connection mechanisms well known to those skilled in the art, thereby providing flexibility in design and performance optimization.

[0138] Example 1: Integrating in-DBD into a polymer The following explains a first embodiment for integrating in-DBD into a polymer: Step P1: Dicycloheptenene containing a bromomethyl group is polymerized using a vinyl addition polymerization catalyst in the first solvent. Monomers undergo polymerization to form brominated polymers.

[0139] (5S,6S)-5,6-bis(bromomethyl)bicyclo[2.2.1]hept-2-ene, which can be used in combination with comonomers, is reacted in a solvent with a suitable vinyl addition polymerization catalyst. Possible solvents include toluene, dichloromethane, or ethers. Other suitable solvents that are generally inert to active catalysts can also be used for similar vinyl addition polymerization reactions of norbornene. Suitable vinyl addition polymerization catalysts may include palladium or nickel catalysts, which may be used alone or in synergy with known cocatalysts. The catalyst-to-monomer ratio can be adjusted to achieve a specific molecular weight, with favorable ratios ranging from 1:50 to 1:50000. The reaction temperature is variable, ranging from ambient conditions to the reflux temperature of the solvent or possibly higher. The reaction is carried out until it is considered complete.

[0140] The reaction progress can be periodically assessed using methods such as colorimetry, spectroscopy, or other relevant analytical methods. After the reaction is complete, the target product, poly[(5S,6S)-5,6-bis(bromomethyl)bicyclo[2.2.1]hept-2-ene], is separated and purified using standard polymer separation methods, including extraction, filtration, or precipitation. The obtained product can be characterized using conventional analytical tools. These tools include, but are not limited to, NMR, gel permeation chromatography (GPC), and infrared spectroscopy.

[0141] Step P2: The brominated polymer is reacted with 1,6-diazabicyclo[4.4.0]decane in a second solvent to produce... Polymers with a bicyclic [4.4.0]decyl group in the side chain

[0142] The product from P1 reacts with 1,6-diazabicyclo[4.4.0]decane in a polar, aprotic solvent that will dissolve the polymer. Possible solvents include, but are not limited to, tetrahydrofuran, toluene, dichloromethane, or ethers. The reaction temperature is variable, ranging from room temperature to the reflux temperature of the solvent or possibly higher. The reaction is allowed to proceed until it is considered complete.

[0143] The reaction process is periodically evaluated using methods such as colorimetry, spectroscopy, or other relevant analytical methods. After the reaction is complete, the target product, denoted as P2 in this embodiment, is separated and purified using standard separation methods, including extraction, filtration, or chromatography. The resulting product can be characterized using conventional analytical tools, including but not limited to NMR, mass spectrometry, and infrared spectroscopy.

[0144] Step P3: The polymer with a side-chain bicyclic [4.4.0]decyl group was reacted with silver salt in a third solvent. The silver salt forms an insoluble salt with the bromomethyl group of the polymer.

[0145] The product from P2 reacts with a suitable silver salt in a selected solvent. This suitable silver salt is soluble in the solvent and can form an insoluble salt with the leaving group of the reactant. Simultaneously, the selected solvent is capable of dissolving both the silver salt and the reactant. Suitable silver salts for this process may include silver tetrafluoroborate, silver nitrate, and silver fluoride. These salts can be generated in situ or introduced individually. Solvents considered suitable for this reaction may include tetrafluoroboric acid, water, nitric acid, and ethers, but this list is not exhaustive.

[0146] The reaction temperature exhibits flexibility, ranging from ambient conditions to the reflux temperature of the specified solvent. The reaction mixture is allowed to react until completion. The reaction progress can be monitored using methods such as colorimetry, spectroscopy, or other relevant analytical methods.

[0147] After the reaction is complete, the target product is separated and purified using standard separation methods (which may include extraction, filtration, or chromatography). The final product can be characterized using conventional analytical tools, such as, but not limited to, NMR, mass spectrometry, and infrared spectroscopy.

[0148] For clarity, specific components mentioned in the chemical reactions, including AgBF4, are used only as exemplary examples. They are not intended to limit or restrict the scope of this disclosure in any way.

[0149] Step P4: The product from step iii) is reacted with a reducing metal in an acidic solvent to generate a reducing group with a side chain. The polymer with side-chain reducing groups is reacted with an oxidant to generate a polymer containing integrated in-DBD. thing

[0150] The product from P3 is then reacted with a suitable reducing metal in a strong acid solvent. In one embodiment, the pH of the acid solvent may be equal to or less than 1. In another embodiment, the acid solvent may be a fully or nearly fully ionized strong acid known in the art, such as HCl, H₂SO₄, HNO₃, HBr, and HBF₄. Such solvents may include tetrafluoroboric acid, sulfuric acid, or hydrochloric acid. Possible reducing metals in this process may include zinc, aluminum, and magnesium, which provide a single electron to reduce the product to form a salt. The temperature at which this reaction proceeds is flexible, ranging from ambient conditions to the reflux temperature of the selected solvent. The mixture is reacted until the reaction is detected to be complete. This reaction stage can be monitored using various methods, such as colorimetric techniques, spectroscopic methods, or other relevant analytical methods.

[0151] Subsequently, any excess reducing metal is separated using techniques that may include filtration or other suitable methods. The reaction mixture is then introduced into a selected oxidizing agent. Suitable oxidizing agents include potassium peroxydisulfate, and those skilled in the art will understand that any peroxide has a substantially similar mechanism, and different peroxides that are single-electron oxidizing agents and sufficiently stable to not explode upon contact with an acid will also be suitable, such as benzoyl peroxide and various organic peroxides. The reaction temperature is also flexible, ranging from ambient conditions to the reflux temperature of the solvent. The mixture is allowed to reach the point of reaction completion, the progress of which can be tracked by methods such as colorimetry, spectroscopy, or other suitable analytical tools.

[0152] Following these steps, the target product is separated and purified. Standard methods may be used for this purpose, including extraction, filtration, or chromatography. Once the final product is obtained, it can be characterized using common analytical instruments, such as NMR, mass spectrometry, and infrared spectroscopy.

[0153] For clarity, the specific components mentioned in the described chemical reactions, including Zn and K2S2O8, are used only as illustrative examples. They are not intended to limit or restrict the scope of this disclosure in any way.

[0154] Example 2: Integrating in-DBD into a polymer The following describes another embodiment of integrating in-DBD into a polymer: Step M1: The bicyclohepten monomer containing a bromomethyl group is reacted with 1,6-diazabicyclo[4.4.0]decane in the first... The first intermediate product is formed by the reaction in a solvent.

[0155] (5S,6S)-5,6-bis(bromomethyl)bicyclo[2.2.1]hept-2-ene is reacted with 1,6-diazabicyclo[4.4.0]decane. Suitable solvents for this reaction are polar aprotic solvents capable of dissolving the polymer, and include, but are not limited to, tetrahydrofuran, toluene, dichloromethane, or ethers. The reaction temperature is flexible, ranging from ambient temperature to the reflux temperature of the selected solvent, or possibly higher. The mixture is allowed to react until the reaction is observed to be complete. The reaction can be monitored using various methods, possibly including colorimetric techniques, spectroscopic methods, or other relevant analytical tools.

[0156] After the reaction is complete, the target product enters the separation and purification stage. This stage can be achieved using established methods, which may include extraction, filtration, or chromatography. Once separated, the final product can be characterized using recognized analytical instruments. These instruments may include NMR, mass spectrometry, and infrared spectroscopy.

[0157] Step M2: The first intermediate product is reacted with a silver salt in a second solvent to generate the second intermediate product.

[0158] The product from M1 reacts with a selected silver salt in a suitable solvent. Advantageously, the silver salt is soluble in this solvent and reacts with the leaving group of the reactant to form an insoluble salt. Simultaneously, the selected solvent is capable of accommodating both the silver salt and the reactant. Suitable silver salts are water-soluble and capable of reacting with halogens (bromine in this example) to form insoluble silver halide salts, and include, but are not limited to, silver tetrafluoroborate, silver nitrate, and silver fluoride, which may be generated in situ or introduced separately. Potential solvents may include tetrafluoroboric acid, water, nitric acid, or ethers, etc. Suitable solvents include tetrafluoroboric acid, water, nitric acid, and ethers, although this list is not exhaustive. Reaction temperatures vary and may range from room temperature to the reflux point of the solvent.

[0159] As the reaction occurs, it is allowed to proceed until its completion is detected. The reaction process can be monitored using a variety of methods, including colorimetric techniques, spectroscopy, or other relevant analytical methods.

[0160] After the reaction, the target product undergoes separation and purification using recognized methods, which may include extraction, filtration, or chromatography. Once separated, the final product can be characterized using established analytical tools, including NMR, mass spectrometry, and infrared spectroscopy.

[0161] For clarity, specific components (including AgBF4) mentioned in the chemical reactions are used only as exemplary examples. They are not intended to limit or restrict the scope of this disclosure in any way.

[0162] Step M3: The second intermediate product is reacted with a reducing metal in an acidic solvent to generate a third intermediate product. The third intermediate is then reacted with an oxidizing agent to generate a fourth intermediate.

[0163] The product from M2 is reacted with a suitable reducing metal in the presence of a strong acid solvent. In one embodiment, the pH of the acid solvent may be equal to or less than 1. In another embodiment, the acid solvent may be a fully or nearly fully ionized strong acid known in the art, such as HCl, H2SO4, HNO3, HBr, and HBF4. A suitable solvent is required to handle both reduction and oxidation reactions and includes, but is not limited to, tetrafluoroboric acid, sulfuric acid, or hydrochloric acid. The reducing metal may be selected from candidate metals such as zinc, aluminum, or magnesium. The reaction temperature range can be from room temperature to the reflux point of the selected solvent.

[0164] During the reaction, it may be advantageous to allow the mixture to react until the reaction is observed to be complete. The reaction process can be observed and tracked using a variety of methods, including but not limited to colorimetric techniques, spectrometry, or other applicable analytical methods. Any excess reducing metal present after the reaction can be conveniently removed by recognized methods, possibly including filtration.

[0165] The reaction mixture is then introduced into a selected oxidizing agent. Suitable oxidizing agents include potassium peroxydisulfate, and those skilled in the art should understand that any peroxide has a substantially similar mechanism, and different peroxides that are single-electron oxidizing agents and sufficiently stable not to explode upon contact with an acid are also suitable. Suitable oxidizing agents that may be considered include benzoyl peroxide or other recognized organic peroxides or oxidizing agents. The reaction temperature varies, potentially ranging from ambient conditions to the solvent reflux point.

[0166] As with the previous steps, it is advantageous to allow the reaction to continue until it is complete, and to monitor its progress by means of means such as colorimetry, spectroscopy or other suitable analytical techniques.

[0167] Once the reaction is complete, the target product can be separated and purified using established separation methods, such as extraction, filtration, or chromatography. After separation, the final product can be characterized using conventional analytical tools, such as NMR, mass spectrometry, and infrared spectroscopy.

[0168] For clarity, specific components mentioned in the chemical reactions, including Zn and K2S2O8, are used only as illustrative examples. They are not intended to limit or restrict the scope of this disclosure in any way.

[0169] Step M4: The fourth intermediate product is reacted with a vinyl addition polymerization catalyst in a third solvent to produce... Polymers containing in-DBD

[0170] The product from M3 reacts with a suitable vinyl addition polymerization catalyst in the presence of a solvent. While the addition of a comonomer could be considered in this process, this description illustrates a simpler potential polymerization method. Solvents used for this purpose may include options such as toluene, dichloromethane, or ethers. Possible catalysts for vinyl addition polymerization may include palladium or nickel catalysts, which may be used alone or in combination with known cocatalysts.

[0171] The ratio of catalyst to monomer is adjustable, allowing control over the molecular weight of the final product. The ratio can be varied, with suitable ranges from 1:50 to 1:50,000 for different applications. The reaction temperature is flexible, potentially ranging from room temperature to above the reflux point of the selected solvent.

[0172] It is advantageous to allow the reaction mixture to proceed until the reaction is complete. Various methods, including but not limited to colorimetric techniques, spectrometry, or other suitable analytical schemes, can be used to effectively monitor the progress of the reaction.

[0173] After the reaction is complete, the final product can be separated and purified using conventional polymer separation methods. These methods may involve techniques such as extraction, filtration, or precipitation. The separated polymer products can be characterized using standard analytical techniques, including NMR, GPC, or infrared spectroscopy.

[0174] Applications of in-DBD polymers in electrochemical applications The above method offers new opportunities for the use of the obtained in-DBD polymers in many different electrochemical applications and devices, including, but not limited to, fuel cells, water electrolyzers, carbon dioxide electrolyzers, and carbon monoxide electrolyzers. Some examples are described below: 1. Polymer ion exchange membrane The ion-exchange in-DBD polymer disclosed herein, or similar ion-exchange polymers containing in-DBD as the main functional group, can be used to form polymer ion-exchange materials (hereinafter referred to as "in-DBD polymer ion-exchange membranes") such as polymer electrolyte membranes (PEMs) and ionomer binders used for electrodes in electrochemical energy conversion devices.

[0175] in-DBD polymer ion exchange membranes can be fabricated using various techniques known in the art, such as solution casting, spraying, and extrusion. To facilitate this process, a suitable organic solvent must be selected to dissolve the in-DBD polymer, thereby promoting the process.

[0176] Depending on the intended application, select a suitable in-DBD polymer or copolymerize it to obtain a film-forming polymer with an ion exchange capacity (IEC, measured in mmol of ionic groups per unit mass of membrane) in the range of 1-4 mmol / g, thereby ensuring high performance.

[0177] The in-DBD polymer can be used as a homogeneous material to form a membrane. Alternatively, the in-DBD polymer can be used as a composite material to form a membrane, wherein other components, which can be polymers, metals, or non-metals, can be added before, during, or after the membrane formation process. The introduction of these components is strategically designed to improve the stability and performance of the resulting composite membrane.

[0178] After forming a homogeneous or composite membrane, post-processing techniques such as crosslinking or post-functionalization can be performed. The main purpose of these additional treatments is to improve the stability and performance of the prepared membrane.

[0179] In some embodiments, the in-DBD polymer ion exchange membrane can be an AEM comprising a polymer matrix as the main structural framework and in-DBD functional groups. When the in-DBD cation structure is introduced into the polymer matrix, it serves to firmly anchor protons within its three-dimensional structure. More specifically, this anchorage is achieved by aliphatic cages formed by the in-DBDs. This structure ensures that the cation charge is firmly maintained and provides resistance to strong anion interactions. Another feature of the in-DBD integration is the symmetrical internal bridgehead hydrogen bonds formed between its nitrogen atoms. This structural advantage provides greater stability, allowing the membrane to maintain its functionality even under harsh conditions such as high temperatures and low relative humidity.

[0180] 2. Enhanced polymer ion exchange membrane In some embodiments, the in-DBD polymer is embedded into a reinforcing material to provide mechanical strength and toughness. The reinforcing process employs a porous substrate, which can be woven or nonwoven and derived from a variety of materials, including but not limited to fluoropolymers such as expanded polytetrafluoroethylene, porous polyethylene or porous polypropylene, electrospun nanofibers, glass fibers, polymer fibers, fiber mats, perforated membranes, and porous ceramics. The method involves impregnating or coating this porous carrier with a liquid composition, which can be the in-DBD polymer in its pure form or dissolved in a suitable solvent. After impregnation, any present solvent is removed, thereby embedding the in-DBD polymer into the porous structure of the reinforcing material. Notably, the porous substrate used is non-conductive.

[0181] 3. Catalyst ink In some embodiments, the catalyst ink comprises an in-DBD polymer (referred to herein as "in-DBD catalyst ink") and is used as an ion-conductive "glue" (commonly referred to as "ionomer"), and is expected to have improved resistance to degradation of the ionomer when exposed to dry conditions compared to conventional catalyst inks.

[0182] The in-DBD catalyst ink composition comprises a catalyst material, an ion-conducting in-DBD polymer, water, and an organic solvent. The in-DBD catalyst ink can be directly applied to a polymer electrolyte membrane or to a porous transport layer (such as carbon paper, woven or nonwoven materials made of suitable materials, or a porous metal-based transport layer). Various known coating processes, such as spraying, screen printing, stencil printing, or offset printing, can be used to deposit the in-DBD catalyst ink to form a catalyst layer. Known fabrication and processing techniques can be used to produce coated films (CCM) or gas diffusion electrodes (GDEs) coated on porous transport layers.

[0183] 4. Catalyst Coated Membrane (CCM) In some embodiments, the CCM comprises the in-DBD polymer (referred to herein as "in-DBD CCM") and is capable of providing good ion contact between the polymer membrane and the catalyst layer ionomer. The in-DBD CCM can be formed by coating the polymer ion exchange membrane with in-DBD catalyst ink, or by using an in-DBD polymer membrane coated with conventional catalyst ink or the in-DBD catalyst ink described above. Typically, the catalyst coating on the polymer ion exchange membrane consists of 5 wt%–35 wt% of the polymer and 65 wt%–95 wt% of a metal or non-metal catalyst.

[0184] The cathode, anode, and / or in-DBD polymer ion exchange membrane of this disclosure can be assembled in a device as individual components, or can be fabricated therein by coating or laminating the in-DBD polymer ion exchange membrane (or a portion thereof) with one or two electrodes or portions thereof. For example, to maximize cost savings and, in some cases, performance, the components or layers thereof can be thin enough that some of the components can act as carriers during the fabrication of the thin layer. The components or portions thereof can be laminated together, formed in situ on the component surface, and / or coated onto the component.

[0185] 5. Membrane Electrode Assembly The in-DBD polymer ion exchange membrane disclosed herein can be placed between the two electrodes (anode and cathode) of the electrochemical device to form a membrane electrode assembly (MEA). In some embodiments, the electrodes are gas diffusion electrodes (GDEs) comprising a gas diffusion layer coated with a catalyst. Gas diffusion layers are known in the art and include, for example, carbon paper or cloth, or a metal mesh. Electrode materials can include, for example, graphitic carbon, glassy carbon, titanium, or any of the following “catalytically active elements”: V, Cr, Mn, Fe, Co, Ni, Cu, Sn, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, Hf, Ta, W, Re, Ir, Pt, Au, Hg, Al, Si, In, Tl, Pb, Bi, Sb, Te, U, Sm, Tb, La, Ce, Nd, and alloys or combinations thereof.

[0186] In some embodiments, the in-DBD polymer is used in electrochemical devices comprising catalytically active nanoparticles. The nanoparticles may be supported on carbon particles or nanostructured supports. The electrochemical device can include electrodes based on catalysts with increased surface area, such as nanostructured thin-film electrodes, nanotube electrodes, porous sponge electrodes, or two-dimensional polycrystalline film electrodes.

[0187] 6. AEM Fuel Cell (AEMFC) In some embodiments, the fuel cell includes one or more of the in-DBD polymer ion exchange membrane, the in-DBD catalyst coating membrane, and / or a catalyst layer containing the in-DBD polymer. The catalyst coating membrane has two sides, one of which is the cathode and the other is the anode. The in-DBD polymer ion exchange membrane can be an AEM (Alternating Electron Membrane), in which case the fuel cell is referred to as an "in-DBD AEM fuel cell" or "in-DBD AEMFC".

[0188] A method of operating an in-DBD AEMFC includes: (a) adjusting the in-DBD AEMFC by supplying hydrogen to the anode and oxygen and water to the cathode, and operating the in-DBD AEMFC at a potential of 1.1 V–0.1 V to generate electrical power and water until the fuel cell reaches at least 90% of its peak performance; and (b) continuing to supply hydrogen to the anode and oxygen and water to the cathode, and operating the in-DBD AEMFC at a potential of 1.1–0.1 V. It should be understood that, unless otherwise stated, devices including the catalyst-coated membrane (e.g., fuel cells, water electrolyzers, etc.) are operated at 1 atm.

[0189] A method for preparing an in-DBD AEMFC includes: (a) pre-adjusting the in-DBD catalyst coating membrane by contacting the catalyst coating membrane with an aqueous hydroxide solution for at least 1 hour to obtain a pre-adjusted catalyst coating membrane; and (b) introducing the pre-adjusted catalyst coating membrane into a fuel cell.

[0190] Another method for preparing an in-DBD AEMFC includes: (a) introducing an in-DBD catalyst-coated membrane into a fuel cell; and (b) preconditioning the fuel cell by contacting the catalyst-coated membrane with an aqueous hydroxide solution for at least 1 hour, thereby providing a preconditioned catalyst-coated membrane.

[0191] A key finding of this disclosure is that in-DBD, as an organic cation, exhibits remarkable stability when exposed to hydroxides. This remarkable property is not only unexpected but also crucial for breakthrough advancements in AEM technology. The ability of in-DBD to remain stable under hydroxide conditions (demonstrated and discussed in detail in the "Experimental Results and Discussion" section below) enhances the lifetime and performance of AEMs. This resistance to hydroxide degradation distinguishes in-DBD AEMs from other current technologies and highlights their transformative potential in electrochemical applications. This property not only enhances the commercial viability of in-DBD AEMFCs but also provides a fundamental framework for future innovations in this field.

[0192] 7. AEM water electrolysis (AEMWE) In some embodiments, the water electrolyzer includes one or more of the following: the in-DBD polymer ion exchange membrane, the in-DBD catalyst coating membrane, and / or a catalyst layer containing the in-DBD polymer (hereinafter referred to as "in-DBD water electrolyzer"). The catalyst coating membrane has two sides, one side being the cathode and the other side being the anode. The anode, cathode, and polymer ion exchange membrane of the in-DBD water electrolyzer can be separate components laminated together.

[0193] A method of operating an in-DBD water electrolyzer includes: (a) supplying water or an aqueous hydroxide electrolyte to the anode, cathode, or both of the anode and cathode of the water electrolyzer; and (b) operating the water electrolyzer to produce hydrogen, oxygen, and water.

[0194] A method of manufacturing an in-DBD water electrolyzer includes: (a) introducing a catalyst-coated or uncoated membrane over the water electrolyzer; and (b) preconditioning the water electrolyzer by contacting the catalyst-coated membrane with an aqueous hydroxide solution for at least 1 hour to provide a preconditioned catalyst-coated membrane.

[0195] Another method of manufacturing an in-DBD water electrolyzer includes: (a) pre-conditioning the catalyst coating membrane by contacting it with an aqueous hydroxide solution for at least 1 hour to provide a pre-conditioned catalyst coating membrane; and (b) introducing the pre-conditioned catalyst coating membrane into the water electrolyzer.

[0196] 8. At AEM-CO 2 Application in COE (carbon monoxide / carbon dioxide electrolysis) In some embodiments, the carbon dioxide and / or carbon monoxide electrolyzer includes one or more of the following: the in-DBD polymer ion exchange membrane, the in-DBD catalyst coating membrane, and / or a catalyst layer containing the in-DBD polymer (hereinafter referred to as "in-DBD CO / CO2 electrolyzer"). The catalyst coating membrane has two sides, one side being the cathode and the other side being the anode.

[0197] A method of operating the in-DBD CO / CO2 electrolyzer includes: (a) supplying water or an aqueous electrolyte to the anode, cathode, or both anode and cathode of the in-DBD CO / CO2 electrolyzer; and (b) operating the carbon dioxide and / or carbon monoxide electrolyzer to generate CO, hydrogen, water, and value-added products, such as, but not limited to, HCO3-. - H₂CO, (HCO₂) - , H2CO2, CH3OH, CH4, C2H4, CH3CH2OH, CH3COO -CH3COOH, C2H6, COOH)2 or (COO - )2.

[0198] Another method of manufacturing the in-DBD CO / CO2 electrolyzer includes: (a) pre-adjusting the catalyst coating membrane by contacting the catalyst coating membrane with an aqueous electrolyte solution for at least 1 hour to provide a pre-adjusted catalyst coating membrane; and (b) introducing the pre-adjusted catalyst coating membrane into the in-DBD CO / CO2 electrolyzer.

[0199] Experimental Results and Discussion 1. Synthesis and structural characterization of in-DBD Maleic hydrazine is oxidized with lead tetraacetate, which reacts with 1,3-butadiene via a Diels-Alder reaction to yield 1,6-diazabicyclo[4.4.0]dec-3,8-dien-2,5-dione. This is subsequently hydrogenated and reduced with LiAlH4 to yield 1,6-diazabicyclo[4.4.0]decane. In THF, monoalkylation with 1,4-dibromobutane followed by further cyclization via the addition of AgBF4 yields 1,6-diazatricyclo[4.4.4.0]decane. 1,6 Tetradecane-1,6-diylonium tetrafluoroborate. In acidic media, the N-N bond is readily reduced with zinc to generate externally protonated DBD tetrafluoroborate, which is subsequently internally protonated in acidic media by oxidation with K₂S₂O₈. This internal protonation occurs via intramolecular H-atom extraction mediated by a single-electron transfer of the DBD β-proton, rather than direct protonation of the diamine, meaning that protons (and any atoms therefrom) cannot penetrate the gaps between the bridgehead nitrogen atoms. Further ion exchange using an ion-exchange resin yields the chloride or hydroxide form.

[0200] In-DBD caged protons in 1 The presence of 17 ppm in the 1H NMR spectrum indicates significant deshielding by two nitrogen atoms. The crystal structure of in-DBD chloride shows an extremely short N…N distance (2.5 Å) with a symmetrical electron density distribution between them, indirectly indicating a symmetrical NHN bond; this hydrogen bond is shorter and more symmetrical than those observed through the proton sponge structure. DFT calculations (ωB97XD / 6-31g(dp)) show that in-DBD is more stable than the externally protonated form at 36.3 kcal / mol, which is far greater than the stability gain obtained by moving protons within the proton sponge (18.7 kcal / mol). In summary, these analyses support the surprising uniqueness of the in-DBD structure.

[0201]

[0202] 1,6-Diazabicyclo[4.4.0]dec-3,8-diene-2,5-dione.

[0203] In a round-bottom flask, DCM (250 mL) and acetic acid (5 mL) were cooled to 0 °C, and maleic hydrazine (5.75 g, 51.26 mmol) and a 20 wt% toluene solution of 1,3-butadiene (34.4 mL, 102.52 mmol) were added. Over approximately 6 hours, lead tetraacetate (25.00 g, 56.38 mmol) was added in approximately 25 portions at 0 °C, allowing each portion to react completely. To monitor the consumption of Pb(OAc)₄, a sample was taken from the tip of a glass pipette and dropped onto a damp paper towel. If the drop was brown, the reaction continued; if the drop remained pale yellow, more Pb(OAc)₄ was added to the reaction. The mixture was warmed to room temperature overnight and then quenched with water. The organic layer was extracted, washed with water, and dried over MgSO₄. After removing the solvent under reduced pressure, the product was ground in diethyl ether (~100 mL) and cooled to -20°C overnight. The product was filtered, and a yellow powder (5.33 g, 32.47 mmol, yield 63%) was collected. 1 H NMR (400 MHz, CDCl3) δ: 6.92 (s, 2H), 6.03 (t, J = 1.4 Hz, 2H), 4.49 (d, J =1.1 Hz, 4H).

[0204] Figure 1 The illustration shows 1,6-diazabicyclo[4.4.0]dec-3,8-diene-2,5-dione in CDCl3. 1 H nuclear magnetic resonance (NMR) spectrum.

[0205]

[0206] 1,6-Diazabicyclo[4.4.0]decane-2,5-dione: In a round-bottom flask, 5% Pd / C (1.7 g) was suspended in deionized water (150 mL). 6,9-1,6-diazabicyclo[4.4.0]dec-3,8-diene-2,5-dione (4.30 g, 26.19 mmol) was added, the top space of the flask was evacuated using a siphon, and hydrogen gas was introduced. 2（g）The hydrogen balloon was refilled three times. The mixture was then stirred at room temperature in an H2 atmosphere for 2 days, and the balloon was refilled when it was nearly depleted. Upon completion of the reaction, the hydrogen was slowly removed under an argon stream, and then diatomaceous earth (15 g) was added and stirred for approximately 10 minutes. The mixture was filtered and washed successively with 0.5 M potassium carbonate solution, water, ethyl acetate, and DCM. All washes were collected and combined, and the product was extracted with DCM × 3. The organic layer was dried with MgSO4 to remove the solvent, yielding a grayish-white powder product (3.68 g, 21.88 mmol, yield 84%). 1 H NMR (400 MHz, CDCl3) δ: 3.74 (m, 4H), 2.60 (s, 4H), 1.71 (p, J = 2.90 Hz, 4H).

[0207] Figure 2 The figure illustrates the presence of 1,6-diazabicyclo[4.4.0]decane-2,5-dione in CDCl3. 1 ¹H NMR. The residual dichloromethane solvent signal is represented as CH₂Cl₂.

[0208]

[0209] 1,6-Diazabicyclo[4.4.0]decane: In a flame-dried 2-necked flask equipped with a reflux condenser, anhydrous THF (60 mL) and 1,6-diazabicyclo[4.4.0]decane-2,5-dione (3.50 g, 20.81 mmol) were mixed under an argon atmosphere and purged with argon for ~30 min. Solid LiAlH4 (3.16 g, 83.23 mmol) was slowly added in portions to the mixture under weak reflux. The mixture was then refluxed under an argon atmosphere for 3 days. The mixture was then cooled, quenched dropwise with water (6 mL, 333.15 mmol), and the solid was filtered off. The solid was collected, ground twice in a separate container of THF (20 mL), and all organic fractions were combined again and concentrated to ~25 mL in a rotary evaporator at 330 mbar and 40 °C. This solution was ready for use in the next reaction without further purification.

[0210]

[0211] 1,6-diaza-1-(4-bromobutyl)bicyclo[4.4.0]decane-1-bromium bromide: In a 150 mL thick-walled glass pressure vessel, 1,6-diazabicyclo[4.4.0]decane (nominal 20.81 mmol) from the previous step was purged in THF (25 mL) with argon for ~10 min. 1,4-dibromobutane (14.91 mL, 124.85 mmol) was added, and the flask was sealed under argon atmosphere and heated to 90 °C overnight. After the reaction cooled, the flask was carefully opened, and precipitation was carried out with diethyl ether (~50 mL). The mixture was cooled to -20 °C overnight, then filtered and washed with cold diethyl ether to give a brown powder product (5.66 g, 15.89 mmol, 76% yield). 1 H NMR (400 MHz, D2O) δ: 3.73 (d, J=13.00 Hz, 2H), 3.66 (t, J=8.54 Hz, 2H), 3.55 (t, J=6.32 Hz, 2H), 3.32 (m, J=4.74 Hz, 2H), 3.11 (m, J=4.92 Hz, 2H), 2.90 (d, J=13.47 Hz, 2H), 1.919-2.037 (m, 4H), 1.764-1.895 (m, 8H).

[0212] Figure 3 The diagram illustrates the role of 1,6-diaza-1-(4-bromobutyl)bicyclo[4.4.0]decane-1-bromium in D2O. 1 H NMR.

[0213]

[0214] 1,6-Diazatricyclo[4.4.4.0] 1,6 Tetradecane-1,6-dimethylonium tetrafluoroborate: In a round-bottom flask, dissolve Ag₂O (3.72 g, 16.06 mmol) in 48% HBF. 4（水溶液） (25 mL) 5-(4-bromobutyl)octahydro-1H-pyridazino[1,2-a]tetradecane-5-bromium (5.20 g, 14.60 mmol) was added in portions to the mixture. The mixture was then heated in an oil bath preheated to 100 °C for 15 min, followed by filtration through a sintered glass filter and washing with 48% HBF4 (10 mL). Ethanol (200 mL) was slowly added to the filtrate, and the mixture was cooled to -20 °C overnight to precipitate. The product was filtered and washed with cold ethanol to obtain a pale brown powder (4.56 g, 12.32 mmol, yield 84%). 1H NMR (400 MHz, D2O) δ: 5.03 (t, J=13.32 Hz, 6H), 3.82 (d, J=14.23 Hz, 6H), 2.49 (t, J=11.41 Hz, 6H), 2.20 (d, J=10.51 Hz, 6H). HRMS (ESI) (m / z, M 2+ Expected value: 98.0964, measured value: 98.0965.

[0215] Figure 4 The diagram illustrates the presence of 1,6-diazatricyclic [4.4.4.0] in D2O. 1,6 Tetradecane-1,6-dimethylonium tetrafluoroborate 1 H NMR.

[0216]

[0217] 1,6-Diazabicyclo[4.4.4]tetradecane-1-onium[exproton]tetrafluoroborate: In a Schlenk flask, purge 48% HBF4 (10 mL) with argon for approximately 10 minutes, then add 1,6-diazotricyclo[4.4.4.0]. 1,6 Tetradecanetetrafluoroborate (2.000 g, 5.406 mmol) was stirred until dissolved. Zinc scrap (1.7673 g, 27.030 mmol) was added, and the mixture was vigorously stirred under argon for 1 hour. The mixture was filtered, washed with a small amount of 48% HBF4 (5 mL), and used for the next reaction.

[0218] Alternatively, to separate the product, degassed 5 M KOH (in its unprotonated form, it is unstable in air and forms insoluble polymers upon exposure, therefore it must be treated under argon—once protonated, it becomes more stable but gradually turns pink) is slowly added to the mixture under argon protection until it becomes alkaline. The mixture is then extracted with degassed diethyl ether × 3, and the extracted organic layer is rapidly added directly to a 1:8 solution of 48% HBF4:diethyl ether. The precipitate is filtered and washed with diethyl ether to obtain a pale pink powder product (81% separation yield). 1 H NMR (400 MHz, D2O) δ: 3.40 (t, J=4.97 Hz, 6H), 2.57 (t, J=5.32 Hz, 6H), 1.97 (p, J=5.54 Hz, 6H), 1.72 (p, J=5.95Hz, 6H). HRMS (ESI) (m / z, M + Expected value: 197.2012, measured value: 197.2017.

[0219] Figure 5 The diagram illustrates the reaction of 1,6-diazabicyclo[4.4.4]tetradecane-1-onium tetrafluoroborate in D2O. 1 HNMR. The residual diethyl ether solvent signal is represented as Et₂O.

[0220]

[0221] 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium[endoproton]tetrafluoroborate: In a Schlenk flask, the filtered crude mixture from the previous reaction (mainly exprotonated BF4 salt (1.536 g, 5.406 mmol) and 48% HBF4 (15 mL)) was purged with argon for ~10 min. Potassium peroxydisulfate (1.461 g, 5.406 mmol) was then added, and the mixture was vigorously stirred under argon for 2 h. The mixture was diluted with diethyl ether (96 mL), the precipitated salt was filtered off, and the solvent was removed under reduced pressure. The mixture was then cooled, KHCO3 (12.000 g, 119.86 mmol) was added to precipitate KBF4, and the mixture was then diluted with anhydrous ethanol (50 mL) and filtered off. The solvent was removed, the product was extracted with anhydrous ethanol, and the solvent was removed under reduced pressure. Because bicarbonate is highly hygroscopic and difficult to handle, the product was converted back to BF4 form by dissolving it in anhydrous ethanol (1 mL) and adding 48% HBF4 (0.7 mL), stirring for 1 h. The product was then diluted with diethyl ether (50 mL) and the liquid was decanted. Finally, the product was recrystallized by cooling to -20°C overnight with ~8 mL of minimum boiling anhydrous ethanol. The precipitate was filtered, washed with a minimal amount of cold ethanol, and then washed with diethyl ether to obtain a white powder product (1.104 g, 3.889 mmol, yield 72%). 1 H NMR (400 MHz, D2O) δ: 16.98 (s, 1H), 2.67 (wide s, 12H), 1.87 (wide s, 12H). 13 C NMR (101 MHz, D2O) delta: 51.71, 25.95. 19 F NMR (376 MHz, D2O) δ: -150.43 (s, 0.2F; 10 B abundance), -150.48 (s, 0.8F; 11 B abundance). HRMS (ESI) (m / z, M + Expected value: 197.2012, measured value: 197.2011.

[0222] Figure 6The diagram illustrates the presence of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium[intrinsic]tetrafluoroborate in D2O. 1 ¹H NMR. The residual diethyl ether and methanol solvent signals are represented by Et₂O and CH₃OH, respectively.

[0223] Figure 7 The diagram illustrates the presence of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium[intrinsic]tetrafluoroborate in D2O. 13 C NMR.

[0224] Figure 8 The diagram illustrates the presence of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium[intrinsic]tetrafluoroborate in D2O. 19 F NMR.

[0225]

[0226] 1,6-Diazabicyclo[4.4.4]tetradecane-1,6-onium chloride [inner proton]: 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium[endoproton]tetrafluoroborate (0.50 g, 1.76 mmol) was dissolved in Milli-Q water (10 mL) and passed through an Amberlite IRA 900-Cl ion exchange resin column (3.5 g) three times until... 19 BF4 signal was not detected by 1F NMR. The solvent was removed under reduced pressure, and the sample was extracted with ethanol and filtered. The solvent was removed under reduced pressure. The solid was ground in diethyl ether and filtered to collect a white powder product (0.35 g, 1.50 mmol, yield 85%). 1 H NMR (400 MHz, CD3OD) δ: 16.95 (s, 1H), 2.70 (wide s, 12H), 1.91 (wide s, 12H). 13 C NMR (101 MHz, D2O) delta: 53.08, 27.32.

[0227] Figure 9 The diagram illustrates the role of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium chloride [inner proton] in CD3OD. 1 H NMR.

[0228] Figure 10 The diagram illustrates the role of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium chloride [inner proton] in CD3OD. 13 C NMR.

[0229] Figure 11The diagram illustrates the role of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium chloride [inner proton] in CD3OD. 19 F NMR.

[0230] Figure 12 The figure illustrates the thermogravimetric analysis of in-DBD Cl at a heating rate of 10 °C / min under a nitrogen atmosphere. The gray line represents 95% of the original mass, which determines the degradation temperature at approximately 388 °C.

[0231] 2. Evaluate the unique stability of in-DBD to alkaline conditions associated with AEM. The stability of in-DBD under strongly alkaline conditions was investigated using two accelerated degradation methods and compared with cations in the prior art; solution NMR was used to identify degradation products, and dynamic vapor adsorption (DVS) was used to investigate the extreme dehydration conditions found in AEM fuel cells. Both assays are limited by practical factors: NMR studies must be performed in solution and are not equivalent to the conditions of gas-phase electrochemical devices; DVS studies provide limited mechanistic insights and can only report degradation products through non-in-situ means. These characterization methods complement each other and provide a more comprehensive insight into the lifetime of cations under device-relevant alkaline conditions.

[0232] 2.1 NMR Degradation Study The inventors employed an NMR spectroscopic degradation method. This method involves collecting NMR spectra every five days in a sealed NMR tube at 80°C using a 2M KOH solution of CD3OH and an internal standard (sodium trimethylsilyl propanesulfonate, NaDSS). Modifications were made to the reported procedure to maintain consistent hydration levels and observe exchangeable protons: the solution was prepared under an argon atmosphere to limit exposure to atmospheric water and carbon dioxide, and CD3OD was used instead of CD3OH. The percentage of remaining cations versus time is shown below. Figure 13 As shown in (A). Under these conditions, no measurable degradation of in-DBD was detected within 30 days. Figure 28 Notably, no proton deuteration exchange was observed, implying the absence of electrophilic α or β protons, and crucially, the inner protons could not be deprotonated or exchanged with other protons. All other cations underwent degradation, characterized by a relatively decreased cation NMR signal intensity. Under these conditions, BTMA degraded rapidly, with less than 15% remaining after 10 days and no cations detectable after 29 days. MMI and DMP showed similar degradation rates, with DMP exhibiting slightly higher stability (65% and 77% cations remaining after 29 and 30 days, respectively). ASU showed high stability compared to other common cations, retaining 95% of its cations after 29 days.

[0233] 1 1H NMR spectra revealed the identified degradation products of all cations, except for in-DBD, for which no degradation products were found. Figure 30 Even after 60 days ( Figure 32 No degradation products were found. BTMA degrades via demethylation and debenzylation. Figure 18 MMI is degraded first through demethylation, followed by C2 attack to generate a ring-opening product. Figure 21 DMP is primarily degraded through demethylation, with a small amount degraded through Hoffmann elimination. Figure 24 ASU is degraded only by Hoffmann elimination. Figure 27 The half-lives of these salts in a 2 M KOH CD3OD solution were estimated based on the slope of their respective degradation curves. Figures 35-39 Since in-DBD did not show degradation within 30 days, its estimated half-life is limited to >100,000 h (>11 years). Figure 13 As shown in (B), in-DBD(t) 1 / 2 The half-life of >100,000 h) compared to ASU (t 1 / 2 ≈ 6950 h) is an order of magnitude longer than MMI or DMP (t 1 / 2 These are approximately 990 h and 1440 h respectively, more than two orders of magnitude longer, and longer than BTMA (t 1 / 2 (≈ 130 h) is more than three orders of magnitude longer.

[0234] In a nitrogen glove box, 85% potassium hydroxide (56 mg), sodium 3-(trimethylsilyl)-1-propanesulfonate (3 mg), and the organic cation salt under study (0.015 mmol) were mixed, then removed from the glove box and placed in a sealed, airtight bottle. Under an argon flow, degassed CD3OD (0.5 mL) was added to the bottle, which was then sealed under argon and sonicated until all solids dissolved.

[0235] NMR samples were prepared under an argon atmosphere to limit moisture in the samples to the natural moisture levels present in KOH particles (85% m / m, λ ≈ 0.55) and commercially available CD3OD (99%), and to exclude CO2 to limit hydroxide carbonation. Under these tightly controlled conditions, the inventors observed a decomposition rate significantly higher than previously published studies, likely due to the much lower hydration number in this study. The rough estimate of the hydration number under these conditions ranges from λ ≈ 0.88 (if no excess hydration or carbonation is present) to λ ≈ 1.75 (if the degree of KOH hydration is twice that expected); this is similar to the hydration number under critical conditions of approximately 10% RH in DVS.

[0236] The resulting solution was transferred to an argon-filled NMR tube under an argon atmosphere and flame-sealed under an argon flow. Samples were then collected. 1 H NMR was performed and placed in an 80°C oil bath, with the sample removed every five days for recording. 1 H NMR. In recording 1 Before obtaining the H NMR data, allow the sample to cool for one hour.

[0237] The NMR was referenced to the trimethylsilane signal of the internal standard NaDSS at 0 ppm. All signals from the NaDSS were integrated, with the signal at 0.595 ppm set as 100. All signal intensities were divided by the number of protons they represented; for example, the signal at 0.595 ppm represented one methylene substituent, and therefore divided by 2, yielding a defined per-proton-integral intensity of 50. The analytes were also integrated, but only for signals present in the initial NMR (day 0); these were also divided by the number of protons they represented to obtain the per-proton intensity of the analyte. The per-proton intensity of each signal was averaged across molecules, and outliers were detected by measuring whether the integrated intensity was more than 20% lower than the average (excluding suspected outliers). Outliers were considered to have significant deuterium exchange and were discarded.

[0238] Figure 14 The figure illustrates the degradation of BTMA on day 0 of the NMR degradation test. 1 H NMR spectrum. Circles represent the proton signal of BTMA, while squares represent the proton signal of NaDSS internal standard.

[0239] Table 1. Examples of NMR hydroxide degradation studies. Integral and average values ​​were used to obtain the integral average value per proton and molecular unit.

[0240]

[0241] Then, divide the total average intensity per proton of the analyte molecules by the total average intensity per proton of the NaDSS internal standard; the resulting value is the relative equivalent of the analyte to NaDSS.

[0242] Relative equivalent = 32.34 / 50.08 = 0.6457 Then, divide that number by the relative equivalent of day 0 to obtain the percentage of remaining analyte over time.

[0243] Table 2. Example of NMR hydroxide stability test: calculation of residual cations.

[0244]

[0245] Figure 15The figure illustrates the experimental blank, the superposition of 2 M KOH (CD3OD) containing the internal standard of sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M). 1 H NMR. Between samples, the NMR tube was heated to 80°C and then cooled before obtaining the next spectrum. The peak near 1.2 ppm was an impurity found in all tested commercial KOH and NaOH sources (multiple batches and suppliers), which did not change during the experiment and did not appear to interfere with the study.

[0246] Figure 16 The figure illustrates the superposition of benzyltrimethylammonium chloride (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 H NMR. Between samples, the NMR tube is heated to 80°C and then cooled before obtaining the next spectrum.

[0247] Figure 17 The figure illustrates the magnified superposition of benzyltrimethylammonium chloride (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR spectra. Between samples, the NMR tube is heated to 80°C and then cooled before obtaining the next spectrum.

[0248] Figure 18 The figure illustrates the effects of benzyltrimethylammonium chloride (0.03 M) on day 29 in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR spectrum. The NMR tube was heated to 80°C for 29 days. The overlay shows the peaks of the remaining analytes (circles) and the peaks of the degradation products (squares).

[0249] Figure 19 The figure illustrates the superposition of 1,3-dimethyl-2-trimethylmethyl-4,5-diphenyl-1H-imidazolium-3-iodide (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR. Between samples, the NMR tube is heated to 80°C and then cooled before obtaining the next spectrum.

[0250] Figure 20The figure illustrates the magnified superposition of 1,3-dimethyl-2-trimethylmethyl-4,5-diphenyl-1H-imidazolium-3-iodide (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR spectra. Between samples, the NMR tube is heated to 80°C and then cooled before obtaining the next spectrum.

[0251] Figure 21 The figure illustrates the effects of 1,3-dimethyl-2-trimethylmethyl-4,5-diphenyl-1H-imidazolium-3-iodide (0.03 M) on day 29 in 2 MKOH (CD3OD) containing the internal standard of sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M). 1 1H NMR spectra. The NMR tube was heated to 80°C for 29 days. The overlay shows the peaks of the remaining analytes (circles) and the peaks of the degradation products (squares).

[0252] Figure 22 The figure illustrates the superposition of 1,1-dimethylpiperidinium iodide (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR. Between samples, the NMR tube is heated to 80°C and then cooled before obtaining the next spectrum.

[0253] Figure 23 The figure illustrates the magnified superposition of 1,1-dimethylpiperidinium iodide (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR spectra. Between samples, the NMR tube was heated to 80°C and then cooled before obtaining the next spectrum. Increased intensity in the frame indicates the formation of a small amount of eliminated products.

[0254] Figure 24 The figure illustrates the effects of 1,1-dimethylpiperidinium iodide (0.03 M) on day 30 in 2 MKOH (CD3OD) containing the internal standard sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M). 1 1H NMR spectrum. The NMR tube was heated to 80°C for 30 days. The overlay shows the peaks of the remaining analytes (circles) and the peaks of the degradation products (squares).

[0255] Figure 25The figure illustrates the superposition of 6-azaspiro[5.5]undecane-6-bromide (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR. Between samples, the NMR tube is heated to 80°C and then cooled before obtaining the next spectrum.

[0256] Figure 26 The figure illustrates the magnified superposition of 6-azaspiro[5.5]undecane-6-bromoonium (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR spectra. Between samples, the NMR tube is heated to 80°C and then cooled before obtaining the next spectrum.

[0257] Figure 27 The figure illustrates day 29 of 6-azaspiro[5.5]undecane-6-bromoonium (0.03 M) in 2 MKOH (CD3OD) containing the internal standard sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M). 1 1H NMR spectra. The NMR tube was heated to 80°C for 29 days. The overlay shows the peaks of the remaining analytes (circles) and the peaks of the degradation products (squares).

[0258] Figure 28 The figure illustrates the superposition of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-chloroonium chloride [inner proton] (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR spectra. Between samples, the NMR tube is heated to 80°C and then cooled before obtaining the next spectrum.

[0259] Figure 29 The figure illustrates the magnified superposition of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-chloroonium chloride [inner proton] (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 HNMR spectra. Between samples, the NMR tube is heated to 80°C and then cooled before obtaining the next spectrum.

[0260] Figure 30The figure illustrates day 29 of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-chlorotonium (inner proton) (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 HNMR spectra. The NMR tube was heated to 80°C for 29 days. The overlay shows the remaining analyte peaks (circles), and the degradation product peaks were not observed and therefore cannot be highlighted.

[0261] Figure 31 The figure illustrates the superposition of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium[intrinon]tetrafluoroborate (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR. Between samples, the NMR tube is heated to 80°C and then cooled before obtaining the next spectrum.

[0262] Figure 32 The figure illustrates the magnified superposition of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium[intrinon]tetrafluoroborate (0.03 M) in 2 MKOH (CD3OD) containing sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard. 1 1H NMR spectra. Between samples, the NMR tube was heated to 80°C and then cooled before obtaining the next spectrum. Increased intensity in areas within the frame indicates regions where degradation products should have been eliminated.

[0263] Figure 33 The diagram illustrates the percentage of residual cations in in-DBD relative to its chloride and BF4 content. – Ionic form.

[0264] A blank experiment was performed using NaBF4 to test the stability of the BF4 anion under NMR test conditions (80°C, 2M KOH in CD3OD solution). The inventors observed that the degradation of the BF4 counterion was similar to that reported for long-term hydrolysis. Figure 34 The intensity fluctuations in the in-DBD BF4 form, with no degradation products observed, are likely due to changes in the chemical environment caused by the loss of BF4 over time.

[0265] Figure 34 The figure illustrates (A) the superposition of sodium tetrafluoroborate (molar concentration) in 2M KOH (CD3OD) containing sodium tetrafluoroborate (molar concentration) as an internal standard. 19F NMR. Between samples, the NMR tube was heated to 80°C and then cooled before obtaining the next spectrum. (B) The integral ratio of the BF3(OH) degradation product signal to the BF4 signal.

[0266] To estimate the half-life of the cations under NMR testing conditions, a graph of the remaining cations versus time was plotted, and the data were fitted to a linear curve with the formula: Y = 1 + b•X, where b is the slope. The half-life of the cations was calculated as Y = 0.5 (i.e., 50% of the cations remaining), and the value of X was calculated in hours. This value was rounded to the nearest 10 hours. Within 30 days, the loss of ~0.5% of the cations has a half-life of approximately 100,000 hours, which is the maximum lifetime that this experiment could resolve.

[0267] Figure 35 The figure illustrates the NMR stability of the residual cation of benzyltrimethylammonium chloride (0.03 M) in 2 MKOH (CD3OD) with sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard over time. The black line represents the linear fit of data collected in the first 10 days.

[0268] Figure 36 The figure illustrates the NMR stability of the residual cation of 1,3-dimethyl-2-trimethylmethyl-4,5-diphenyl-1H-imidazolium-3-iodide (0.03 M) in 2 MKOH (CD3OD) with the internal standard of sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as a function of time. The black line represents a linear fit of the collected data.

[0269] Figure 37 The figure illustrates the NMR stability of the residual cation of 1,1-dimethylpiperidinium iodide (0.03 M) in 2 MKOH (CD3OD) with the internal standard of sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) over time. The black line represents the linear fit of the collected data.

[0270] Figure 38 The figure illustrates the NMR stability of the residual cation of 6-azaspiro[5.5]undecane-6-bromide (0.03 M) in 2 MKOH (CD3OD) with the internal standard of sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as a function of time. The black line represents the linear fit of the collected data.

[0271] Figure 39The figure illustrates the NMR stability of the residual cation of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-chloroonium[inner proton] (0.03 M) in 2 MKOH (CD3OD) with sodium 3-(trimethylsilyl)-1-propanesulfonate (0.03 M) as an internal standard over time. The black line represents a linear fit of the collected data.

[0272] 2.2 Dynamic vapor adsorption (DVS) degradation study Extreme AEM fuel cell cathode conditions were simulated under solvent-free, low-hydration conditions. The inventors employed a method to investigate these conditions via DVS of hydroxide salts. These studies typically show that organic cations undergo significant degradation even under moderate relative humidity (60%–30%) conditions, as hydroxide anions become more nucleophilic upon removal of hydrated water. Furthermore, to date, no organic cation hydroxide salts have been reported to persist at 80°C and relative humidity below 10%. Figure 41 DVS gravimetric analysis of hydroxide-form cations at 80 °C is shown. Considering the increased nucleophilicity of hydroxides at low λ, the inventors defined critical conditions of 30% and 10% relative humidity, which are expected to be the lower RH ranges reported for normal cycling of AEM fuel cells at high current densities. In AEM fuel cells, only cations with stability below 10% RH are expected to remain stable over long periods, thus providing a wider operating window for the fuel cell. A RH range scan from high to low RH conditions shows the RH range at which each cation begins to degrade, observing mass loss due to the volatilization of (volatile) degradation products and decreased hygroscopicity. Intermittent rehumidification of the cations to the point of no degradation (stable reference RH) shows the effect of degradation, observing a decrease in water absorption due to loss of hygroscopic ionic species under the same conditions. At 10% RH, in-DBD ( Figure 40 (A) Remains stable, with only a slight mass loss (1.2% h) at 80°C and 8% RH. -1 At 5% RH, the mass loss rate increases (6.4% h), while at 5% RH, the mass loss rate increases (6.4% h). -1 DMP exhibits higher degradation sensitivity as RH decreases. Figure 40 (B)), where degradation begins at up to 23% RH (0.6% h) -1 Significant degradation occurred at 11% RH (2.2% h⁻¹). -1 ASU ( Figure 40 (C)) at up to 23% RH (0.8% h -1 It begins to degrade at 17% RH, and degrades significantly at 17% RH (3.4% h). -1 MMI ( Figure 40 (D)) at a moderate 49% RH (4.2% h -1 The degradation is relatively rapid. The relative humidity at which cations begin to degrade is as follows: Figure 52 As shown in the figure, this clearly demonstrates that in-DBD is the only cationic hydroxide that can persist under the low humidity conditions of gas-phase AEM technology.

[0273] Figure 40 The figure illustrates the dynamic vapor adsorption (DVS) degradation study of cation-hydroxides. The DVS mass of (A) in-DBD OH, (B) DMP OH, (C) ASU OH, and (D) MMI OH changes over time as RH decreases at 80 °C. The samples were exchanged for their OH groups in degassed Milli-Q water (or 1:1 MeOH:H₂O for MMI) using freshly regenerated ion exchange resin under an argon flow. - The data is stored under argon atmosphere until use. The solid and gray lines represent normalized mass (left axis), while the black dashed line represents RH (right axis). 30% RH to 10% RH is considered a critical condition; therefore, before and after these conditions, the RH is returned to a stable reference (55%) RH to observe the degradation-related decrease in hygroscopicity. The gray dashed arrows indicate the mass at the reference RH before degradation; the middle and right regions represent the 30%–10% RH and 10%–0% RH conditions, respectively. The shading indicates the RH region where degradation occurs for each cation, while the adjacent numbers represent the RH at which significant degradation (>2% mass loss / h) is first observed when RH is reduced.

[0274] To evaluate long-term stability under high-stress conditions with low RH, cations in hydroxide form were exposed to 11% RH at 80°C. Since in-DBD, DMP, and ASU showed almost 100% volatilization of degradation products, the observed mass loss could serve as a quantitative indicator of degradation, where the mass loss rate was essentially the decomposition rate. It should be noted that the decomposition rate could not be collected because MMI contained a large amount of non-volatile degradation products. Figure 41 As shown in (A), in-DBD hydroxides were highly stable, with a relatively small mass loss (1.3%) observed within 12.2 hours. DMP lost more mass within the experiment (4.4%), while ASU lost the largest mass (20.2%). The half-lives of these cations are as follows: Figure 41As shown in (B), the half-life of in-DBD (450 h) is almost 3.5 times longer than that of DMP (130 h) and an order of magnitude longer than that of ASU (30 h). By applying these complementary degradation methods (solution NMR and gas-phase DVS), the inventors were able to reflect the observed differences in stability conversion from ex-situ solution degradation studies (highly stable) to in-situ operated polymer studies (poor stability) using ASU, and demonstrate that in-DBD is not affected when converting solution stability to gas-phase stability. Compared to other cations, in-DBD is substantially more stable in both degradation test methods and exhibits unprecedented stability at 80 °C and approximately 10% RH, conditions associated with AEM fuel cells.

[0275] Figure 41 The figure illustrates the DVS stability test of a fully volatile cationic hydroxide. (A) Normalized mass loss over time. (B) Extraction half-life of the cation at 11% RH and 80°C.

[0276] To determine the degradation products of in-DBD, the DVS effluent was collected in a 5% v / v acetic acid solution. The only observed degradation product was a Hoffmann-type elimination product (…). Figures 60-62 No other degradation products were observed, and in particular, the caged protons did not undergo deprotonation, indicating incredible stability provided by inlay protection and enhanced hydrogen bonding. Calculations (shown below) reveal why only one degradation product was observed, where the inlay protection prevents the hydroxide from approaching the central proton, and the low electrophilicity of the α and β positions requires very harsh conditions before elimination.

[0277] DVS degradation experiments were performed on the hydroxide form of the studied ions. To ensure minimal carbonation of the ions, all operations were conducted under an argon atmosphere.

[0278] The Amberlyst A26-OH ion exchange resin was renewed by adding fresh resin (as is) to a Schlenk flask, followed by the addition of degassed Milli-Q water. The mixture was purged with argon for 1 hour, and then KOH (85%) particles were added to the mixture under argon atmosphere to prepare a ~1 M KOH solution. The mixture was left to stand under argon atmosphere for approximately 2 hours and regenerated at least twice (2 hours each time) under argon atmosphere with freshly degassed 1 M KOH solution, removing the old solution using a syringe under argon atmosphere. The resin was then washed with degassed Milli-Q water × 3 under argon atmosphere, and then stored in a sealed Schlenk flask with excess degassed Milli-Q water under argon atmosphere until use.

[0279] Under an argon atmosphere, 1 g of freshly renewed Amberlyst A26-OH resin was loaded into a pasteurized pipette with a small cotton pad (for holding the resin) and washed three times with degassed Milli-Q water. Under an argon atmosphere, 50 mg of the corresponding halide cation was dissolved in 1 mL of degassed Milli-Q water (or, for MMI iodide, 1.5 mL of a degassed 1:1 MeOH:H2O mixture). The solution was added to the resin under an argon atmosphere, allowing it to be discharged by gravity into a clean glass vial purged with argon. This solution was then returned to the column at least twice, each time collected in a fresh argon-purged vial. The column was then rinsed with 0.5 mL of degassed Milli-Q water (or degassed 1:1 MeOH:H2O) and collected in the last vial. This last solution was argon-sealed, the vial closed, and sealed with electrical tape (3M) until use (storage time not exceeding 1 hour).

[0280] An aqueous solution of the organic cation-hydroxide salt (or, for MMI hydroxide, a 1:1 MeOH:H2O solution) was added to a DVS crucible (Pt crucible, 0.5 mL) and rapidly loaded into the DVS under an argon flow (200 SCCM). The pH of the remaining solution was then tested for direct samples (pH 12–13 recorded for all samples) and the ionic conductivity of samples diluted 8-fold (Omega CDH-7021) to ensure that the majority of anions were hydroxide anions.

[0281] A conductivity of 2.4 mS / cm represents the conductivity of pure hydroxide in a ~0.012 M solution; therefore, conductivity higher than this is considered to be for most organic salts in the OH- form. 0.53 mS / cm represents pure HCO3-. - Conductivity is a significant factor, and therefore most carbonated samples fail to exhibit these conductivity values. For example, after hydroxide exchange in in-DBD, a conductivity of 3.0 mS / cm was recorded at ~0.012 M, indicating that the relative contribution of cations and anions primarily requires hydroxide as the mobile anion.

[0282] The DVS sample was dried at 80°C and 55% RH (nominal 60% RH) under an argon flow (200 SCCM total) until stable mass was achieved for at least 1 hour. The RH was varied using a step-by-step procedure while maintaining the flow rate (200 SCCM) and oven temperature (80°C), as shown below.

[0283] Collect the remaining solution after exchange 1 H NMR was used to ensure that no degradation was observed on the column, and the remaining material was collected after the DVS experiment was completed. 1¹H NMR. The remaining material is a combination of non-volatile degradation products, carbonated salts, and unexchanged halide salts.

[0284] To determine sample degradation, the data were normalized to the average mass at a pre-degradation reference RH (55%). The last 30 minutes of each RH value were taken, and the data were fitted to a linear slope (y = mx + b). Degradation was defined as the observation of a mass loss exceeding 0.2% within the 30 minutes (based on the fitted data). Significant degradation was defined as the observation of a mass loss exceeding 1% within the 30 minutes (based on the fitted data).

[0285] Figure 42 The diagram illustrates (A) the original relative humidity of the DVS study relative to time and (B) the last 30 minutes of each new (or reference) RH.

[0286] Figure 43 The figure illustrates the DVS analysis of in-DBD hydroxides at reduced relative humidity levels. The temperature was maintained at 80°C throughout the experiment. The gray line corresponds to the gray axis on the left; the black dashed line corresponds to the black axis on the right.

[0287] Figure 44 The figure illustrates the superposition of in-DBD hydroxides before and after the DVS experiment. 1 H NMR spectra. The “pre-DVS” sample is a hydroxide-exchanged cation and allows for carbonation in open air for several days before solvent removal to obtain NMR spectra.

[0288] Figure 45 The figure illustrates the DVS analysis of DMP hydroxide at reduced relative humidity levels. The temperature was maintained at 80°C throughout the experiment. The gray line corresponds to the left gray axis; the black dashed line corresponds to the right black axis.

[0289] Figure 46 The figure illustrates the superposition of DMP hydroxide before and after the DVS experiment. 1 H NMR spectrum. The “pre-DVS” sample is a hydroxide-exchanged cation and allows carbonation in open air for several days before solvent removal to obtain the NMR spectrum.

[0290] Figure 47 The figure illustrates the DVS analysis of ASU hydroxide at reduced relative humidity levels. The temperature was maintained at 80°C throughout the experiment. The gray line corresponds to the left gray axis; the black dashed line corresponds to the right black axis.

[0291] Figure 48 The figure illustrates the superposition of ASU hydroxide before and after the DVS experiment. 1H NMR spectrum. The “pre-DVS” sample is a hydroxide-exchanged cation and allows carbonation in open air for several days before solvent removal to obtain the NMR spectrum.

[0292] Figure 49 The figure illustrates the DVS analysis of MMI hydroxides at reduced relative humidity levels. The temperature was maintained at 80°C throughout the experiment. The gray line corresponds to the left gray axis; the black dashed line corresponds to the right black axis.

[0293] Figure 50 The figure illustrates the superposition of MMI hydroxides before and after the DVS experiment. 1 H NMR spectrum. The “pre-DVS” sample is a hydroxide-exchanged cation and allows carbonation in open air for several days before solvent removal to obtain the NMR spectrum.

[0294] Figure 51 The figure illustrates the superposition of four cationic hydroxides obtained after their respective DVS experiments and permitted for carbonation treatment. 1 1H NMR spectrum. The arrows point to common impurities / artifacts generated in the experiment rather than from degradation products.

[0295] Figure 52 The figure illustrates the initial and significant degradation of cation-hydroxide extracts as determined by DVS experiments at 80 °C. The estimated λ level was obtained from the in-DBD hydroxide isotherms shown below. Light bars indicate RH at which no degradation was observed; dashed lines indicate areas where mass loss exceeded 0.4% but was less than 2% per hour at a specified RH; dark bars indicate RH at which mass loss exceeded 2% per hour. Horizontal boxes represent the defined critical conditions from 30% to 10% RH.

[0296] Figure 53 The figures illustrate (A) DVS analysis of in-DBD hydroxides at 60°C and reduced relative humidity levels. (B) Plotting the last 30 minutes of each relative humidity (RH) step. The two gray areas represent RH conditions of 30%–10% and 10%–0%, respectively. Shaded areas indicate RH at which degradation occurred, while the adjacent numbers indicate the first RH at which significant degradation was observed. The gray line corresponds to the left gray axis, and the black line corresponds to the right black axis.

[0297] Figure 54 The figures illustrate (A) humidity isotherms of in-DBD hydroxides at 60°C and 80°C, with hydration numbers estimated from the slope to 0% RH. (B) humidity isotherms of four cation-hydroxides studied at their original mass relative to relative humidity (since the stability of all ions except in-DBD is insufficient to estimate mass at 0% RH).

[0298] Control experiments showed that hydroxides were the main degradation form, while MMI iodides did not degrade under the test conditions. Figure 55 , Figure 56 ), while MMI hydroxide is almost completely degraded ( Figure 49 , Figure 50 ).

[0299] Figure 55 The figure illustrates the DVS control analysis of MMI iodides at reduced relative humidity levels. The temperature was maintained at 80°C throughout the experiment. The gray line corresponds to the left gray axis, and the black dashed line corresponds to the right black axis.

[0300] Figure 56 The figure illustrates the superposition of MMI iodides before and after the DVS experiment. 1 H NMR spectrum. The experiment removed a small amount of residual DMSO through the airflow, which was reflected in a small amount of mass loss.

[0301] Figure 57 The figures illustrate the DVS mass trace of ASU hydroxide relative to time at 80°C. (A) Experimental mass and RH trace during the experiment, and (B) Mass and RH trace of the data after each measurement has stabilized at RH. The dashed line represents the reference (stable) 55% RH before degradation, and the dotted dashed line represents the initial mass at the test 11% RH. The gray line corresponds to the gray axis on the left; the black dashed line corresponds to the black axis on the right.

[0302] Figure 58 The figure illustrates the DVS mass trace of DMP hydroxide relative to time at 80°C. (A) Experimental mass and RH trace during the experiment, (B) Mass and RH trace of the data after each measurement has stabilized at RH. The dashed line represents the reference (stable) 55% RH before degradation, and the dotted dashed line represents the initial mass at 11% RH during the test. The gray line corresponds to the gray axis on the left, and the black dashed line corresponds to the black axis on the right.

[0303] Figure 59 The figures illustrate the DVS mass trace of in-DBD hydroxides relative to time at 80°C. (A) Experimental mass and RH trace during the experiment, and (B) Mass and RH trace of the data after each measurement has stabilized at RH. The dashed line represents the reference (stable) 55% RH before degradation, and the dotted dashed line represents the initial mass at 11% RH during the test. The gray line corresponds to the gray axis on the left, and the black dashed line corresponds to the black axis on the right.

[0304] To calculate the DVS half-life of the cations at 11% RH, the time after RH stabilization (time = 800 min) was set to time = 0. The mass remaining after decomposition at RH = 0 and rehydration to RH = 11% was considered the non-degradable mass and was subtracted from the mass at each point on the degradation curve (between t = 800 min and t = 1520 min at RH = 11%). The mass at t = 0 minus the non-degradable mass was considered the degradable mass. This assumption was made because all three cations studied (ASU, DMP, in-DBD) had 100% volatile degradation products, and the inventors would advise against making this assumption if the studied cations left non-volatile degradation products. This is why MMI was not included in the DVS half-life calculation.

[0305] The degradation curve was fitted to a linear curve, with the formula: Y = m d + b•X, where b is the slope and m is the slope. d The degradable mass is given. The half-life of the cation is calculated as follows: Y = 0.5 (remaining 50% of the cation), and the value of X is calculated in hours. This value is rounded to the nearest 10 hours.

[0306] To capture the degradation products of in-DBD, the escaping gas from the DVS degradation experiment was bubbled through a 5% v / v aqueous acetic acid solution. The resulting solution was dried under reduced pressure, the residue was collected, and characterized by NMR and MS.

[0307] Figure 60 The figure illustrates the DVS escaping gas collected after complete degradation of in-DBD trapped in a 5% v / v acetic acid solution. 1 1H NMR spectra. Only identified product protons are labeled; poor integrated quality is attributed to tautomerism of protonated nitrogen and / or inversion of the nitrogen center, resulting in a variety of chemical environments. The circle at 17 ppm is used to emphasize the absence of caged protons in the degradation products, indicating complete degradation.

[0308] Figure 61 The figure illustrates the DVS escaping gas collected after complete degradation of in-DBD trapped in a 5% v / v acetic acid solution. 13 C10 NMR spectrum. Only the carbon atoms of the identified products are labeled.

[0309] Figure 62 The figure illustrates the positive ion mass spectrum of the DVS escape gas collected after complete degradation of in-DBD trapped in a 5% v / v acetic acid solution. Only the identified products are shown, with their theoretical m / z values ​​indicated.

[0310] 2.3 Density Functional Theory (DFT) Calculation DFT calculations were performed at the theoretical level of ωB97XD / 6-31g(dp). The optimized structure of in-DBD shows that its HOMO isosurface is mainly distributed along the NHN axis, and a large amount of electron density is also located on the α-carbon next to the N-atom. Figure 64 The LUMO isosurface indicates that the orbitals are mainly located between the carbon rings. Figure 63 (A)), and there is a node on the carbon ring and along the NHN axis; the presence of these two nodes indirectly indicates that hydroxide attack at these locations is highly unfavorable. The electrostatic potential (ESP) of in-DBD is as follows: Figure 63 As shown in (B). This indicates that the interstitial spaces between alkyl rings are the regions with the highest positive electrostatic potential, and therefore the sites where hydroxide ions are expected to attack; this would cause the hydroxide to remain in impermeable (see below) interstitial spaces, where Hoffmann-type elimination reactions would be geometrically unfavorable, and this may be one of the reasons for the hydroxide's high stability.

[0311] Figure 63 The figures illustrate the DFT calculation results for the cation. (A) LUMO isosurface of in-DBD and (B) electrostatic potential (ESP) of in-DBD. ESP is expressed in Hartree atomic units, where a larger positive number indicates a stronger positive potential and higher electrophilicity. (C) Free energy difference between the parent cation and degradation products, calculated in an aqueous continuous medium model. Degradation products not observed in the experiment are indicated by dashed lines. (D) Energy barrier required to deprotonate the caged protons of in-DBD. The structure shows OH The process of approaching the caged protons. DFT calculations were performed at the theoretical level of ωB97XD / 6-31g(dp).

[0312] The inventors performed DFT calculations to further understand the reason for the high stability of in-DBD hydroxides. The free energies and relative energies of the cationic degradation products were calculated, such as... Figure 63(C) shows that degradation products are generally much more stable than the parent cation hydroxide. Both DMP and MMI show stabilization energies of 30–45 kcal / mol for degradation products, while ASU shows a considerably low energy difference of ~31 kcal / mol for degradation via Hoffman-type elimination; and ~35 kcal / mol for OH- addition products not observed experimentally. in-DBD shows that elimination is extremely unfavorable, stabilizing only ~17 kcal / mol. Deprotonated DBD is theoretically more stable by ~30 kcal / mol relative to the parent cation, while the hypothetical hydroxide addition product is similarly stable by ~32 kcal / mol. The energy barrier for deprotonation caused by hydroxide permeation into in-DBD was calculated ( Figure 63 (D) is very large (~400 kcal / mol), confirming why this pattern was not observed. Notably, although the OH addition products of in-DBD were calculated, the inventors did not observe any of these compounds. The combination of the lack of a potentiophilic point, a high energy barrier to internal deprotonation, and a low energy difference between the elimination products and the parent cation can be used to explain the extremely high stability of in-DBD.

[0313] Figure 64 The figure illustrates the calculated orbital isosurfaces for HOMO and LUMO in-DBD. Calculations were performed at the theoretical level of ωB97XD / 6-31g(dp).

[0314] Figure 65 The illustrations show the generation energy calculations for the relative energies of external protonation versus internal protonation in in-DBD (left two images) and typical proton sponges (right two images). Calculations were performed at the theoretical level of ωB97XD / 6-31g(dp).

[0315] In summary, the inventors have demonstrated that in-DBD is more resistant to hydroxide anion-induced degradation than existing "stable" organic cations. The combination of embedded protection (cage structure) and enhanced monopore hydrogen bonding enables in-DBD hydroxides to persist at 80°C and 5% RH. The inventors emphasize that in-DBD is significantly more stable in solution and vapor states than other studied cations, all of which exhibit variable stability depending on the testing methods used; this suggests that in-DBD may indeed be a widely applicable cationic group for alkaline AEM technologies, particularly gas-phase AEM technologies. The unprecedented ultra-high stability of in-DBD hydroxides at high temperatures, both in solution and at low humidity, has the potential to overcome the current limitations of AEM fuel cells and various AEM-based devices such as CO / CO2 electrolyzers and dry cathode water electrolyzers.

[0316] While some embodiments have been described above, it should be understood that other embodiments are possible and are intended to be included in this invention. Those skilled in the art will appreciate that modifications and adaptations to the embodiments not shown above are possible.

[0317] It should be noted that the above description is merely illustrative of embodiments, and actual implementations may vary in many ways. While this embodiment outlines a specific set of chemical reactions, compounds, or preparations, various elements in this configuration may be substituted, modified, or completely omitted without diminishing the essence of this disclosure. For example, the methods of synthesis or analysis may differ, alternative reactants or solvents may be used, or different experimental parameters may be employed. Potential chemical processes or synthetic routes can be extensively modified to accommodate different reaction conditions, material properties, or technological advancements. The inherent flexibility of this system allows for extensive customization, ensuring that the resulting compounds or reactions can be as diverse as the chemistry they represent while maintaining consistency in the fundamental principles.

[0318] In this disclosure, the term "module" can refer to laboratory equipment, software components, or a combination of both. Laboratory equipment may include, but is not limited to, specific chemical reactors, analytical devices, spectrometers, or chromatographic systems. Software components may involve computer code stored in memory and executable by a processor, firmware, or scripts. The provided modules may be implemented in various forms, either independently or in combination, and the functionality described herein may be partitioned among multiple modules or integrated into a single module depending on design choices and specific implementation methods.

[0319] Various embodiments have been described with reference to sequences and block diagrams of methods, apparatus, systems, and chemical processes. In this regard, the depicted sequences and diagrams illustrate the architecture, functionality, and operation of various embodiments. For example, each block in the diagram may represent a specific step, reaction, or part of synthesis, encompassing one or more specific actions for carrying out the process. In some alternative embodiments, the actions represented in these blocks may not occur in the described order. For example, depending on the functions involved, two blocks shown consecutively may be executed substantially simultaneously or in reverse order.

[0320] The terminology used herein is for descriptive purposes only and is not intended to be limiting. Therefore, unless the context clearly indicates otherwise, terms such as “molecule,” “compound,” “reactant,” and “product” are intended to include both singular and plural forms. It should also be understood that terms such as “comprising” and “encompassing” specify the presence of the stated feature or component but do not exclude the presence or addition of other features or components. Phrases such as “in solution,” “in a mixture,” or “under reaction conditions” are used for relative reference only and are not intended to imply any limitation on the described process.

[0321] Phrases such as “at least one of A, B, and C,” “at least one of A, B, or C,” “one or more of A, B, and C,” and “A, B, and / or C” are intended to cover both a single entry in the enumerated list of entries and multiple entries in the list. The phrases “at least one of…,” “one or more of…,” and similar phrases used in conjunction with the list do not necessarily imply that every entry in the list must be present.

[0322] It is contemplated that any aspect or portion of any implementation discussed in this specification can be implemented or combined with any other portion, unless such portions are mutually exclusive. While every effort has been made to provide a detailed and accurate description, it should be noted that the scope of this disclosure is not limited to the exact configurations and implementations described. This specification is intended to illustrate the principles of this disclosure and not to limit its scope, which is defined by the appended claims and their potential applications in other fields.

Claims

1. A method for synthesizing 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium (in-DBD), comprising: i) In the presence of 1,3-butadiene, or before mixing with 1,3-butadiene, maleic hydrazine is oxidized with 1,3-butadiene to generate 1,6-diazabicyclo[4.4.0]dec-3,8-diene-2,5-dione; ii) Hydrogenation of 1,6-diazabicyclo[4.4.0]dec-3,8-diene-2,5-dione; iii) Reduce hydrogenated 1,6-diazabicyclo[4.4.0]dec-3,8-diene-2,5-dione with a reducing agent to produce 1,6-diazabicyclo[4.4.0]decane; iv) Monoalkylation of 1,6-diazabicyclo[4.4.0]decane with 1,4-substituted butane derivatives having leaving groups at positions 1 and 4; v) To prepare 1,6-diazabicyclo[4.4.0]decane tetrafluoroborate by cyclizing a monoalkylated 1,6-diazabicyclo[4.4.0]decane through addition to a metal salt. 1,6 Tetradecane-1,6-dimethylonium; vi) In an acidic medium, 1,6-diazatricyclo[4.4.4.0] is reduced with a reducing metal other than sodium. 1,6 The N / N bond of tetradecane-1,6-dimethylonium forms an externally protonated DBD tetrafluoroborate; and vii) In an acidic medium, the externally protonated DBD tetrafluoroborate is internally protonated by oxidation with a single-electron oxidant to generate in-DBD.

2. The method according to claim 1, wherein the product of step i) is separated by extraction and recrystallized in a solvent selected from the group consisting of dichloromethane (DCM), toluene and diethyl ether.

3. The method according to claim 1, wherein the reducing agent in step iii) is selected from the group consisting of LiAlH4, NaBH4, diisobutylaluminum hydride (DIBAL-H) ​​and Et3SiH, or includes Wolff-Kishner reduction.

4. The method according to claim 1, wherein the 1,4-substituted butane derivative in step iv) is 1,4-dibromobutane, 1,4-diiodobutane, or 1,4-dichlorobutane.

5. The method according to claim 1, wherein the 1,4-substituted butane derivative in step iv) has a substituent at one or more positions at the 2 or 3 position of the butane chain.

6. The method according to claim 1, wherein the reducing metal in step vi) is selected from the group consisting of zinc, magnesium and aluminum.

7. The method according to claim 1, wherein the single-electron oxidant in step vii) is peroxydisulfate, wherein the cation of the peroxydisulfate is selected from potassium ions (K ions). + Sodium ions (Na) + ), ammonium ions (NH4) + ) and lithium ion (Li + A group consisting of ).

8. The method according to claim 1, wherein the single-electron oxidant in step vii) is selected from the group consisting of hydrogen peroxide (H2O2), benzoyl peroxide and its salts.

9. The method according to claim 1, wherein the solvent in step iv) is tetrahydrofuran (THF).

10. The method according to claim 1, wherein the metal salt in step v) is silver tetrafluoroborate (AgBF4).

11. The method according to claim 1, wherein the acidic medium in step vi) or vii) comprises tetrafluoroboric acid (HBF4).

12. The method according to claim 1, wherein the acidic medium used in steps vi) and vii) is the same acidic medium.

13. The method according to claim 1, wherein the externally protonated DBD tetrafluoroborate generated in step vi) is air stable, and wherein the reduction in step vi) and the internal protonation in step vii) are performed sequentially without the need to separate the externally protonated DBD tetrafluoroborate.

14. A method for integrating in-DBD into a polymer, the method comprising: i) To prepare a brominated polymer, a vinyl addition polymerization catalyst is used in a first solvent to polymerize a dicyclohepten monomer containing a bromomethyl group; ii) The brominated polymer is reacted with 1,6-diazabicyclo[4.4.0]decane in a second solvent to generate a polymer with a side-chain bicyclo[4.4.0]decyl group; iii) React the polymer with the side-chain bicyclic [4.4.0]decyl group with a silver salt in a third solvent, wherein the silver salt forms an insoluble salt with the bromomethyl group of the polymer; iv) The product of step iii) is reacted with a reducing metal in an acidic solvent to generate a polymer with reducing groups on the side chains; and v) React the polymer with side-chain reducing groups with an oxidant to generate a polymer containing integrated in-DBD.

15. The method of claim 14, wherein the vinyl addition polymerization catalyst is selected from the group consisting of palladium catalysts, nickel catalysts, and combinations thereof, and wherein the first solvent in step i) is selected from the group consisting of toluene, dichloromethane, and ether.

16. The method of claim 14, wherein the second solvent in step ii) is selected from the group consisting of tetrahydrofuran, toluene, dichloromethane and ether.

17. The method according to claim 14, wherein the silver salt in step iii) is selected from the group consisting of silver tetrafluoroborate, silver nitrate and silver fluoride, and the third solvent in step iii) is selected from the group consisting of tetrafluoroboric acid, water and nitric acid.

18. The method of claim 14, wherein the reducing metal in step iv) is selected from the group consisting of zinc, aluminum and magnesium, and the acid solvent in step iv) is selected from the group consisting of tetrafluoroboric acid, sulfuric acid and hydrochloric acid.

19. The method of claim 14, wherein the oxidant in step v) is a single-electron oxidant, and wherein the single-electron oxidant is selected from potassium ions (K+). + Sodium ions (Na) + ), ammonium ions (NH4) + ) and lithium ion (Li + The group consists of peroxydisulfate of the cations.

20. The method according to claim 14, wherein the brominated polymer in step i) is poly[(5S,6S)-5,6-bis(bromomethyl)bicyclo[2.2.1]hept-2-ene], and wherein in step i), the ratio of catalyst to monomer is 1:50 to 1:50000.

21. A method for integrating in-DBD into a polymer, the method comprising: i) React a bicyclohepten monomer containing a bromomethyl group with 1,6-diazabicyclo[4.4.0]decane in a first solvent to generate a first intermediate product; ii) React the first intermediate with the silver salt in a second solvent to generate a second intermediate; iii) React the second intermediate with a reducing metal in an acidic solvent to generate a third intermediate; iv) React the third intermediate with an oxidizing agent to generate a fourth intermediate; v) The fourth intermediate is reacted with a vinyl addition polymerization catalyst in a third solvent to prepare a polymer containing integrated in-DBD.

22. The method of claim 21, wherein the first solvent in step i) is selected from the group consisting of tetrahydrofuran, toluene, dichloromethane and ether.

23. The method according to claim 21, wherein the silver salt in step ii) is selected from the group consisting of silver tetrafluoroborate, silver nitrate and silver fluoride.

24. The method according to claim 21, wherein the acid solvent in step iii) is selected from the group consisting of tetrafluoroboric acid, sulfuric acid and hydrochloric acid, and wherein the reducing metal in step iii) is selected from the group consisting of zinc, aluminum and magnesium.

25. The method according to claim 21, wherein the oxidant in step iv) is potassium persulfate.

26. The method of claim 21, wherein the third solvent in step v) is selected from the group consisting of toluene, dichloromethane and ether, and wherein the vinyl addition polymerization catalyst in step v) is selected from the group consisting of palladium catalyst and nickel catalyst.

27. The method of claim 21, wherein the ratio of catalyst to monomer in step v) ranges from 1:50 to 1:50000.

28. An in-DBD polymer, comprising: Polymer matrix; and The 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium (in-DBD) cationic structure integrated into the polymer matrix, in, The cation charge of the in-DBD cation structure is carried by fixed protons within an aliphatic cage formed by the three-dimensional structure of the in-DBD cation structure, and is stabilized between the two nitrogen atoms of the in-DBD cation structure by symmetrical intra-bridgehead hydrogen bonds.

29. The in-DBD polymer of claim 28, wherein the polymer matrix is ​​selected from the group consisting of: polysulfone, polyphenylene, polyaryletherketone, polyphenylene ether, polyethylene, polypropylene, polystyrene, polybenzimidazole, and polynorbornene.

30. The in-DBD polymer of claim 29, wherein the polymer matrix is ​​connected to the in-DBD cationic structure at multiple locations.

31. A polymer ion exchange membrane comprising the in-DBD polymer according to any one of claims 28-30.

32. A catalyst ink comprising a catalyst material, water, an organic solvent, and the in-DBD polymer according to any one of claims 28-30.

33. A catalyst-coated membrane comprising a polymer ion exchange membrane coated with the catalyst ink of claim 32.

34. A catalyst-coated membrane comprising the polymer ion exchange membrane of claim 31, and coated with a catalyst.

35. A membrane electrode assembly comprising an anode layer, a cathode layer, and a polymer ion exchange membrane according to any one of claims 28-30 between the anode layer and the cathode layer.

36. A fuel cell comprising at least one of the polymer ion exchange membrane of claim 31, the catalyst ink of claim 32, and the catalyst coating membrane of claim 33 or claim 34.

37. An electrolyzer comprising at least one of the polymer ion exchange membrane of claim 31, the catalyst ink of claim 32, and the catalyst coating membrane of claim 33 or claim 34.

38. The use of 1,6-diazabicyclo[4.4.4]tetradecane-1,6-onium (in-DBD) as a cationic functional group in the preparation of anion exchange membranes (AEMs), wherein the cationic charge of the in-DBD is carried by a fixed proton within an aliphatic cage formed by the three-dimensional structure of the in-DBD and is stabilized between the two nitrogen atoms of the in-DBD by symmetrical intra-bridge hydrogen bonds.

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