Modified ionomer, method of modifying same, and use in membrane electrodes

Abstract

The application discloses a modified ionomer, which comprises a Nafion solution and an aliphatic multifunctional monomer. The modified ionomer provided by the application inhibits the agglomeration of the ionomer and IrO2 by using the aliphatic multifunctional monomer to self-assemble with the side chain sulfonic acid groups of the ionomer, the uniform distribution of the ionomer and the IrO2 catalyst improves the proton and electron transmission capacity, the porous structure promotes the gas and water transmission, and thus an anode catalyst layer with more micropores and more uniform distribution of the ionomer and the catalyst is obtained. The application further discloses a modification method of the modified ionomer and application of the modified ionomer in a membrane electrode. Test tests show that the membrane electrode prepared from the modified ionomer can make the electrolytic tank performance reach 2.98 A cm ‑2 @1.9 V 0.5 mg cm ‑2 , the catalyst utilization rate reaches 0.053 g Ir ·kW ‑1 , which is almost half of the target of 0.1 g Ir ·kW ‑1 of the International Renewable Energy Agency (IRENA) in 2026, and has good economic and social benefits.

Description

Technical Field

[0001] This invention belongs to the field of electrolytic electrode technology, specifically relating to a modified ionomer, its modification method, and its application in membrane electrodes. The modified ionomer can promote the separation of the nafion ionomer phase in the anodic catalyst layer of the membrane electrode. Background Technology

[0002] Proton exchange membrane electrolysis (PEMWE), as a highly efficient hydrogen production technology, has attracted widespread attention in recent years. Due to the harsh environment of the anodic oxygen evolution reaction (OER), iridium (Ir) is typically used as the anode catalyst. However, the high cost and limited resources of iridium restrict its large-scale application. To promote the commercialization of PEMWE, the U.S. Department of Energy (DOE) has set a PEMWE development target for 2025 (DOE 2025): 1.9V@3A cm⁻²@0.5mg·cm⁻². -2 However, with ultra-low noble metal loading, proton, electron, and gas-water transport within the anode catalyst layer will be limited, preventing the electrolyzer from operating at high current densities. Currently, the operating current density of electrolyzers is typically below 2 A·cm⁻¹. -2 The loading of precious metal catalysts is as high as 2 mg·cm³. -2 There is still a significant gap between the current performance and the set goals. Therefore, improving mass transfer in the anode catalyst layer to enhance electrolyzer performance is crucial for the commercialization of PEMWE.

[0003] Currently, there are two main methods to enhance the mass transport capacity of the PEMWE anode catalyst layer. One method involves preparing oxygen evolution reaction (OER) catalysts with high conductivity and high catalytic activity, aiming to reduce the noble metal loading by improving catalytic activity. Using inexpensive metal oxides as Ir-based catalyst supports is an effective approach, including Ir / MnO2, IrCoOx, Ir / NiO, Ir / CoOOH, and Ir / Co3O4. The intrinsic activity of the catalyst is enhanced by modulating the interaction between the unique electronic structure of the uniformly dispersed active sites and the matrix material. Catalysts prepared using this method can achieve 10 mA·cm⁻¹ activity with only a 244 mV overpotential. -2While the current density was significantly improved, the performance still couldn't meet the application requirements of PEM electrolyzers. Another approach is to modify the macroscopic structure of the anode catalyst layer to enhance mass transport capabilities, including constructing ordered anode catalyst layers and gradient-porous anode catalyst layers. For example, Dong et al. used nanoimprinting to prepare an anode catalyst layer with a gradient conical array structure. This gradient conical array structure can expose more active sites, increase catalyst utilization, and improve electron and gas-liquid transport capabilities. Jiang et al. used a hydrothermal method to prepare an ordered array nanostructure electrode, achieving efficient gas-liquid transport with low noble metal loading. Electrolyzer test results showed that this electrode can reduce mass transfer losses, reaching 2.2 A·cm at 2.0 V. -2 The current density. Lv et al. prepared an anode catalyst layer with hierarchical pores using a pore-forming agent, which reduced the overpotential by 163 mV at the same current density compared to a conventional anode catalyst layer. Currently, many studies attempt to improve proton, electron, and gas-water transport processes by modifying the anode catalyst layer structure. These ideas are inspired by the relatively mature fuel cells, but the Pt / C catalyst used in fuel cells has completely different properties from the IrO2 catalyst. IrO2 is highly hydrophilic with a high surface energy, while Pt / C is hydrophobic, so IrO2 itself is more prone to agglomeration, and the strong interaction between the ionomers and IrO2 exacerbates the agglomeration phenomenon. A thick ionomer film tightly wraps the surface of the agglomerates, restricting the on-board transport pathway of protons and causing the electron transport pathway to be blocked. Summary of the Invention

[0004] This invention aims to at least partially address one of the technical problems in related art. Therefore, the main objective of this invention is to provide a modified ionomer that improves membrane electrode performance by promoting the phase separation of Nafion ionomers in the anolyte catalyst layer. This invention also provides a method for modifying this modified ionomer, and its application in membrane electrodes.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A modified ionomer comprising a Nafion solution and an aliphatic multifunctional monomer.

[0007] In some specific embodiments, the aliphatic multifunctional monomer is one of aliphatic polyols, aliphatic polyamines, and aliphatic polyacids;

[0008] Furthermore, the aliphatic multifunctional monomer is an aliphatic polyol, and the aliphatic polyol is one or more of 1,4-cyclohexanediethanol, cyclohexanetriethanol, cyclohexanediol, and cyclohexanehexaol.

[0009] In some specific embodiments, the mass ratio of the Nafion solution to the aliphatic multifunctional monomer is 5-15:1.

[0010] In some specific embodiments, the Nafion solution has a mass concentration of 2-10 wt%.

[0011] The present invention also aims to provide a method for modifying the aforementioned modified ionomers, comprising the following steps:

[0012] 1) Weigh the Nafion solution according to the formula requirements, disperse it by ultrasonication, and obtain the reaction solution;

[0013] 2) Add an aliphatic multifunctional monomer to the reaction solution and continue ultrasonic dispersion to carry out the coordination reaction.

[0014] The purpose of this invention is to provide an application of the aforementioned modified ionomer in membrane electrodes.

[0015] In some specific embodiments, an oxygen evolution catalyst slurry is coated on the anode of the proton exchange membrane, the oxygen evolution catalyst slurry containing the aforementioned modified ionomer.

[0016] In some specific embodiments, the oxygen evolution catalyst slurry includes IrO2 powder, modified ionomer solution, solvent and water, and the ratio of IrO2 powder, modified ionomer solution, solvent and water is (20-40) mg: (40-60) mg: (5-10) ml: (1-5) ml.

[0017] Furthermore, the IrO2 powder has an iridium content of 70 wt%, the solvent is n-propanol, and the water is deionized water with a resistivity of 18.2 MΩcm.

[0018] Furthermore, the oxygen evolution catalyst slurry is prepared by adding and mixing water, IrO2 powder, water, n-propanol, and modified ionomer solution in sequence according to the formula requirements, and then ultrasonically treating the mixture to obtain the oxygen evolution catalyst slurry.

[0019] In some specific embodiments, the membrane electrode is prepared as follows: hydrogen evolution catalyst slurry is injected into an ultrasonic spraying machine and sprayed in a serpentine pattern, alternating between horizontal and vertical spraying. After spraying, it is dried and then flipped over. At the same time, oxygen evolution catalyst slurry is injected into the injection pump of the ultrasonic spraying machine and sprayed horizontally and vertically alternately on the flipped anode. After drying, the membrane electrode is obtained.

[0020] In some specific embodiments, the hydrogen evolution catalyst slurry comprises Pt / C powder, an ionomer solution, a solvent, and water.

[0021] Furthermore, the Pt / C powder has a platinum content of 40 wt%, the ionomer solution is a 5 wt% Nafion solution, the solvent is n-propanol, and the water is deionized water with a resistivity of 18.2 MΩcm.

[0022] In some specific embodiments, the hydrogen evolution catalyst slurry is obtained by the following preparation method:

[0023] Take 10-20 mg of Pt / C powder, 40-60 mg of ionomer solution, 1-3 mL of n-propanol and 3-10 mL of deionized water and mix them. Sonicate the mixture in an ice bath for 10-30 minutes to obtain the hydrogen evolution catalyst slurry for the cathode.

[0024] In some specific embodiments, the ultrasonic spraying machine is configured with the following parameters: slurry (hydrogen evolution catalyst slurry and / or oxygen evolution catalyst slurry) feed rate 0.3 mL / min; ultrasonic power 2.2 W; nozzle moving speed 60 mm / s; nozzle step distance 3 mm; nozzle height 60 mm; air inlet pressure 1.5 psi; vacuum heating plate 90 °C.

[0025] Compared with the prior art, the present invention has at least the following advantages:

[0026] 1) The modified ionomer provided by the present invention inhibits the aggregation of ionomer and IrO2 by using the self-assembly of aliphatic multifunctional monomers and sulfonic acid groups on the side chain of the ionomer, thereby obtaining an anode catalyst layer with more micropores and a more uniform distribution of ionomer and catalyst.

[0027] 2) The modified ionomer provided by this invention optimizes agglomeration by altering the interaction between the ionomer and IrO2. The uniform distribution of the ionomer and IrO2 catalyst enhances proton and electron transport capabilities, while the porous structure promotes gas-water transport, enabling the electrolyzer to achieve a performance of 2.98 A·cm⁻¹. -2 @1.9V@0.5mg·cm -2 The catalyst utilization rate reached 0.053g. Ir ·kW -1 . Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below.

[0029] Figure 1 This is a dynamic light scattering analysis diagram of the modified ionomer in Example 2 of the present invention;

[0030] Figure 2 This is the 1H NMR spectrum of the modified ionomer in Example 2 of the present invention;

[0031] Figure 3 This is the Fourier transform infrared (FTIR) spectrum of the modified ionomer in Example 2 of the present invention;

[0032] Figure 4 This is a small-angle scattering test image of the modified ionomer in Example 2 of the present invention;

[0033] Figure 5 This is a SEM image of the anode catalyst layer prepared by the modified ionomer in Example 2 of the present invention.

[0034] Figure 6 This is an AFM conductivity test diagram of the anode catalyst layer prepared by the modified ionomer in Example 2 of the present invention;

[0035] Figure 7 The figure shows the electrochemical performance test results of the membrane electrode prepared by the modified ionomer in Example 2 of this invention. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are merely descriptive and not limiting, and should not be construed as limiting the scope of protection of the present invention.

[0037] When a quantity, concentration, or other value or parameter is described as a range, preferred range, or preferred upper and lower limits, it should be understood that it is equivalent to specifically disclosing any range by combining any pair of upper or preferred values ​​with any lower or preferred values, regardless of whether the range is specifically disclosed. Unless otherwise stated, the numerical range values ​​listed herein include the endpoints of the range and all integers and fractions within that range.

[0038] Unless otherwise stated, all percentages, parts, ratios, etc. in this document are by weight.

[0039] Unless otherwise stated, all percentages, parts, ratios, etc., in this document are by weight. The materials, methods, and examples described herein are exemplary and should not be construed as limiting unless otherwise specified. Unless otherwise specified, all raw materials, equipment, or apparatus used in the production and testing processes are commercially available or obtained by conventional methods in the art.

[0040] In the following examples, the Nafion solution had a mass fraction of 5 wt% and was purchased from DuPont; the IrO2 powder had an Ir mass fraction of 84% and was purchased from Alfaesa; the Pt / C mass fraction was 40% and was purchased from DuPont; the 1,4-cyclohexanediethanol mass fraction was 99.0% and was purchased from Maclean's; and the n-propanol mass fraction was 99% and was purchased from Maclean's.

[0041] The aliphatic multifunctional monomer is one of aliphatic polyols, aliphatic polyamines, and aliphatic polyacids, and the aliphatic polyol is one or more of 1,4-cyclohexanediethanol, cyclohexanetriethanol, cyclohexanediol, and cyclohexanehexaol. The following embodiments use 1,4-cyclohexanediethanol as an example for specific explanation.

[0042] Example 1

[0043] This embodiment provides a method for preparing a membrane electrode, which specifically includes the following steps:

[0044] S1: Nafion ionomer modification

[0045] Weigh 80 mg of 5 wt% Nafion solution and sonicate for 10 minutes; add 10 mg of 1,4-cyclohexanediethanol to the reaction solution and continue sonicating for 30 minutes to allow 1,4-cyclohexanediethanol to coordinate with the Nafion ionomer, thus obtaining a modified Nafion ionomer solution.

[0046] S2: Coating the surface of the proton exchange membrane with a catalyst.

[0047] The proton exchange membrane (commercial Nafion 115) is placed on the vacuum heating plate of an ultrasonic spraying machine, and the catalyst slurry is sprayed onto the proton exchange membrane by ultrasonic spraying. The specific steps include:

[0048] S2.1: Cathode-sprayed hydrogen evolution catalyst slurry

[0049] Specifically, step S2.1 involves mixing 15 mg of Pt / C powder, 50 mg of ionomer solution, 2 mL of n-propanol, and 6 mL of deionized water. The mixture is then subjected to ultrasonic treatment in an ice bath for 20 minutes to obtain the hydrogen evolution catalyst slurry for the cathode. The Pt / C powder contains 40 wt% platinum, the ionomer solution is a 3 wt% perfluorosulfonic acid resin solution, the solvent is n-propanol, and the water is deionized water with a resistivity of 18.2 MΩcm.

[0050] The hydrogen evolution catalyst slurry was injected into the injection pump of an ultrasonic spraying machine. The ultrasonic spraying machine was set with the following parameters: slurry feed rate 0.3 mL / min; ultrasonic power 2.2 W; nozzle movement speed 60 mm / s; nozzle step distance 3 mm; nozzle height 60 mm; inlet pressure 1.5 psi; vacuum heating plate 90℃. The catalyst slurry was sprayed in a serpentine pattern with alternating horizontal and vertical directions, ultimately achieving a cathode catalyst loading of 0.08 mg Pt / cm³. 2 After the spraying is completed and dried for 30 minutes, the surface is flipped over for the anode catalyst layer spraying.

[0051] S2.2: Anodic spraying of oxygen evolution catalyst slurry

[0052] Step S2.2 specifically involves: taking 20 mg of IrO2 powder, 40 mg of modified Nafion ionomer solution (obtained in step S1), 5 mL of n-propanol, and 2 mL of deionized water (added in two equal portions), and mixing them in the following order: water-IrO2 powder-water-n-propanol-modified Nafion ionomer solution. After ultrasonically treating the mixture for 20 minutes, the oxygen evolution catalyst slurry for the anode is obtained. The IrO2 powder contains 70 wt% iridium, the modified Nafion ionomer solution is in n-propanol as the solvent, and the water is deionized water with a resistivity of 18.2 MΩcm.

[0053] The oxygen evolution catalyst slurry was injected into the injection pump of an ultrasonic spraying machine. The settings of the ultrasonic spraying machine were the same as those used for the cathode catalyst layer spraying. The oxygen evolution catalyst slurry was sprayed alternately on the flipped anode in both horizontal and vertical directions, ultimately achieving an anode catalyst loading of 0.35 mg. Ir / cm 2 After spraying, dry for 30 minutes to obtain the membrane electrode.

[0054] Example 2

[0055] This embodiment provides a method for preparing a membrane electrode, which specifically includes the following steps:

[0056] S1: Nafion ionomer modification

[0057] Weigh 120 mg of 5 wt% Nafion solution and sonicate for 10 minutes. Add 10 mg of 1,4-cyclohexanediethanol to the reaction solution and continue sonicating for 30 minutes to allow the 1,4-cyclohexanediethanol to coordinate with the Nafion ionomer, thus obtaining a modified Nafion ionomer solution.

[0058] S2: Coating the surface of the proton exchange membrane with a catalyst.

[0059] The proton exchange membrane (commercial Nafion 115) is placed on the vacuum heating plate of an ultrasonic spraying machine, and the catalyst slurry is sprayed onto the proton exchange membrane by ultrasonic spraying. The specific steps include:

[0060] S2.1: Cathode-sprayed hydrogen evolution catalyst slurry

[0061] Specifically, step S2.1 involves mixing 15 mg of Pt / C powder, 50 mg of ionomer solution, 2 mL of n-propanol, and 6 mL of deionized water. The mixture is then subjected to ultrasonic treatment in an ice bath for 20 minutes to obtain the hydrogen evolution catalyst slurry for the cathode. The Pt / C powder contains 40 wt% platinum, the ionomer solution is a 3 wt% perfluorosulfonic acid resin solution, the solvent is n-propanol, and the water is deionized water with a resistivity of 18.2 MΩcm.

[0062] The hydrogen evolution catalyst slurry was injected into the injection pump of an ultrasonic spraying machine. The ultrasonic spraying machine was set with the following parameters: slurry feed rate 0.3 mL / min; ultrasonic power 2.2 W; nozzle movement speed 60 mm / s; nozzle step distance 3 mm; nozzle height 60 mm; inlet pressure 1.5 psi; vacuum heating plate 90℃. The catalyst slurry was sprayed in a serpentine pattern with alternating horizontal and vertical directions, ultimately achieving a cathode catalyst loading of 0.1 mg Pt / cm³. 2 After the spraying is completed and dried for 30 minutes, the surface is flipped over for the anode catalyst layer spraying.

[0063] S2.2: Anodic spraying of oxygen evolution catalyst slurry

[0064] Step S2.2 specifically involves: taking 30 mg of IrO2 powder, 50 mg of modified Nafion ionomer solution (obtained in step S1), 7 mL of n-propanol, and 3 mL of deionized water (added in two equal portions), and mixing them in the following order: water-IrO2 powder-water-n-propanol-modified Nafion ionomer solution. After ultrasonically treating the mixture for 20 minutes, the oxygen evolution catalyst slurry for the anode is obtained. The IrO2 powder contains 70 wt% iridium, the modified Nafion ionomer solution is in n-propanol as the solvent, and the water is deionized water with a resistivity of 18.2 MΩcm.

[0065] The oxygen evolution catalyst slurry was injected into the injection pump of an ultrasonic spraying machine. The settings of the ultrasonic spraying machine were the same as those used for the cathode catalyst layer spraying. The oxygen evolution catalyst slurry was sprayed alternately on the flipped anode in both horizontal and vertical directions, ultimately achieving an anode catalyst loading of 0.4 mg. Ir / cm 2 After spraying, dry for 30 minutes to obtain the membrane electrode.

[0066] Example 3

[0067] This embodiment provides a method for preparing a membrane electrode, which specifically includes the following steps:

[0068] S1: Nafion ionomer modification

[0069] Weigh 150 mg of 5 wt% Nafion solution and sonicate for 10 minutes. Add 10 mg of 1,4-cyclohexanediethanol to the reaction solution and continue sonicating for 30 minutes to allow the 1,4-cyclohexanediethanol to coordinate with the Nafion ionomer, thus obtaining a modified Nafion ionomer solution.

[0070] S2: Coating the surface of the proton exchange membrane with a catalyst.

[0071] The proton exchange membrane (commercial Nafion 115) is placed on the vacuum heating plate of an ultrasonic spraying machine, and the catalyst slurry is sprayed onto the proton exchange membrane by ultrasonic spraying. The specific steps include:

[0072] S2.1: Cathode-sprayed hydrogen evolution catalyst slurry

[0073] Specifically, step S2.1 involves mixing 15 mg of Pt / C powder, 50 mg of ionomer solution, 2 mL of n-propanol, and 6 mL of deionized water. The mixture is then subjected to ultrasonic treatment in an ice bath for 20 minutes to obtain the hydrogen evolution catalyst slurry for the cathode. The Pt / C powder contains 40 wt% platinum, the ionomer solution is a 3 wt% perfluorosulfonic acid resin solution, the solvent is n-propanol, and the water is deionized water with a resistivity of 18.2 MΩcm.

[0074] The hydrogen evolution catalyst slurry was injected into the injection pump of an ultrasonic spraying machine. The ultrasonic spraying machine was set with the following parameters: slurry feed rate 0.3 mL / min; ultrasonic power 2.2 W; nozzle movement speed 60 mm / s; nozzle step distance 3 mm; nozzle height 60 mm; inlet pressure 1.5 psi; vacuum heating plate 90℃. The catalyst slurry was sprayed in a serpentine pattern with alternating horizontal and vertical directions, ultimately achieving a cathode catalyst loading of 0.12 mg Pt / cm³. 2 After the spraying is completed and dried for 30 minutes, the surface is flipped over for the anode catalyst layer spraying.

[0075] S2.2: Anodic spraying of oxygen evolution catalyst slurry

[0076] Step S2.2 specifically involves: taking 40 mg of IrO2 powder, 60 mg of modified Nafion ionomer solution (obtained in step S1), 10 mL of n-propanol, and 5 mL of deionized water (added in two equal portions), and mixing them in the following order: water-IrO2 powder-water-n-propanol-modified Nafion ionomer solution. After ultrasonically treating the mixture for 20 minutes, the oxygen evolution catalyst slurry for the anode is obtained. The IrO2 powder contains 70 wt% iridium, the modified Nafion ionomer solution is in n-propanol as the solvent, and the water is deionized water with a resistivity of 18.2 MΩcm.

[0077] The oxygen evolution catalyst slurry was injected into the injection pump of an ultrasonic spraying machine. The settings of the ultrasonic spraying machine were the same as those used for the cathode catalyst layer spraying. The oxygen evolution catalyst slurry was sprayed alternately on the flipped anode in both horizontal and vertical directions, ultimately achieving an anode catalyst loading of 0.43 mg. Ir / cm 2 After spraying, dry for 30 minutes to obtain the membrane electrode.

[0078] Performance testing:

[0079] This application uses Example 2 as an example to conduct performance tests on the modified ionomer in this invention and the membrane electrode containing the modified ionomer, specifically as follows:

[0080] 1) Structural characterization

[0081] This application characterizes the structure of the Nafion ionomer obtained in step S1 of Example 2, specifically as follows:

[0082] 11) This application performs dynamic light scattering (DLS) analysis on the Nafion ionomer prepared in step S1 of Example 2, and the results are as follows: Figure 1 As shown in the figure, CHDM (1,4-cyclohexanediethanol) forms a self-assembled structure with Nafion, and its dispersion is transparent; both dispersions exhibit a single ionomer particle distribution. Figure 1 The presence of a single peak indicates that the sample is monodisperse, with similar aggregate particle sizes and less aggregation. The presence of a single particle peak indicates that the block copolymer has successfully self-assembled into a stable structure. The average particle size of Nafion-CHDM (248.6 nm) is significantly smaller than that of Nafion (340.8 nm), which indicates that the Nafion-CHDM dispersion has better dispersibility and stability.

[0083] 12) When the Nafion ionomer prepared in step S1 of Example 2 is used as an anode binder, it undergoes a phase transition from an aqueous dispersion to a solid state; therefore, this test example performed 1H NMR spectroscopy analysis on the solid ionomer, and the results are as follows: Figure 2 As shown, the hydroxyl hydrogen in the Nafion-CHDM ionomer mixture exhibited an up-field shift (3.64 ppm) compared to pure CHDM (4.39 ppm), indicating that the chemical environment of the hydroxyl hydrogen in the Nafion-CHDM ionomer is close to that of the sulfonate group (3.63 ppm).

[0084] In addition, Fourier transform infrared (FTIR) spectroscopy was performed on the solid ionomer in this test example, and the results are as follows: Figure 3 As shown in the figure, the hydroxyl stretching vibration peak (3,417 cm⁻¹) in the Nafion-CHDM HP film is red-shifted compared to that in the Nafion film (3,477 cm⁻¹), indicating the formation of hydrogen bonds. This relatively weak interaction lowers the molecular vibrational frequency. In PFSA ionomers, the phase separation between ionic and nonpolar regions plays a crucial role in their ionic conductivity and mechanical properties.

[0085] Furthermore, this test case also included small-angle scattering (SAS) testing on the solid ionomer, with results as follows: Figure 4As shown in the figure, the scattering rings associated with ion domain expansion in the dry Nafion membrane are almost invisible (left). However, the two-dimensional (2D) SAXS plot of the Nafion-CHDM membrane shows significant scattering rings (right), indicating that the internal structure of the Nafion-CHDM membrane is uniformly distributed in all directions, corresponding to isotropic phase separation between hydrophilic and hydrophobic water domains.

[0086] In summary, using CHDM self-assembled Nafion ionomers can effectively improve the phase separation degree of ionomers and enhance the proton transport rate.

[0087] 2) Appearance and morphology

[0088] This test example uses Example 2 to compare the uniform distribution performance of the modified Nafion ionomer solution (Nafion-CHDM) of this invention with that of a traditional Nafion ionomer solution (Nafion). Specifically:

[0089] 21) The morphology of the anode catalyst layers prepared from modified Nafion ionomer solution and unmodified Nafion ionomer solution was examined using electron microscopy (SEM). The results are as follows: Figure 5 As shown in the figure, when observed at low magnification, large white lumps corresponding to large ionomer aggregates can be seen on the surface of the anode catalyst layer using Nafion ionomer solution, while a relatively uniform surface is observed on the surface of the anode catalyst layer using Nafion-CHDM (modified Nafion ionomer solution).

[0090] 3) Conductivity test of anode catalyst

[0091] This test example uses atomic force microscopy (AFM) to analyze the anode catalyst layers prepared from modified Nafion ionomer solutions and unmodified Nafion ionomer solutions. AFM conductivity measurements show that the Nafion anode catalyst layer exhibits a significant region of low electronic conductivity, indicating uneven ionomer distribution and weak charge transport capability. Figure 6 In contrast, the anode catalyst layer of Nafion-CHDM exhibits a larger conductive area, indicating enhanced bonding between the ionomer and catalyst particles. This improved conductivity, consistent with the uniform dispersion observed in height measurements, highlights the effectiveness of Nafion-CHDM in promoting electron transport. Consistent with the in-plane conductivity measurements of the anode catalyst layer, the conductivity of the Nafion-CHDM anode catalyst layer is 1.64 times that of Nafion.

[0092] The AFM conductivity test of the anode catalyst in this application shows that the anode catalyst layer of Nafion-CHDM has a more favorable charge transport environment, ensuring the uniform distribution of ionomers.

[0093] 3) Electrochemical performance

[0094] This test example demonstrates the electrical performance testing of the membrane electrode prepared from the modified ionomer in this application, specifically as follows:

[0095] A PEMWE electrolyzer using Nafion-CHDM was constructed. Test results were obtained within the electrolysis voltage range of 1.2–2.0 V. Figure 7 As shown in the figure, the electrolysis current density of the Nafion-CHDM anode catalyst layer is significantly higher than that of the Nafion anode catalyst layer. The Nafion-CHDM anode catalyst layer can achieve an electrolysis current density of 2.98 A·cm⁻¹. -2 @1.9V@0.5mg PGM ·cm -2 Its superior performance is close to the DOE 2025 target (3A·cm). -2 @1.9V@0.5mg PGM ·cm -2 Correspondingly, the catalyst utilization rate was 0.053 g. Ir ·kW -1 This almost meets the International Renewable Energy Agency (IRENA) 2026 target of 0.1g. Ir ·kW -1 Half of it.

[0096] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A modified ionomer for proton exchange membrane anode oxygen evolution catalyst slurry, characterized in that, It includes a Nafion solution and an aliphatic multifunctional monomer, wherein the aliphatic multifunctional monomer is an aliphatic polyol, and the aliphatic polyol is one or more of 1,4-cyclohexanediol, cyclohexanetriol, cyclohexanediol, and cyclohexanehexaol, and the mass ratio of the Nafion solution to the aliphatic multifunctional monomer is 5-15:

1.

2. A method for modifying the modified ionomer according to claim 1, characterized in that, Includes the following steps: 1) Weigh the Nafion solution according to the formula requirements, disperse it by ultrasonication, and obtain the reaction solution; 2) Add an aliphatic multifunctional monomer to the reaction solution and continue ultrasonic dispersion to carry out the coordination reaction.

3. An oxygen evolution catalyst slurry, characterized in that, The oxygen evolution catalyst slurry contains the modified ionomer as described in claim 1.

4. The oxygen evolution catalyst slurry according to claim 3, characterized in that, It comprises IrO2 powder, modified ionomer solution, solvent and water, and the ratio of IrO2 powder, modified ionomer solution, solvent and water is (20-40) mg: (40-60) mg: (5-10) ml: (1-5) ml, wherein the solvent is n-propanol.

5. The oxygen evolution catalyst slurry according to claim 4, characterized in that, It is obtained by the following preparation method: according to the formula requirements, the modified ionomer solution-water-n-propanol-IrO2 powder are added and mixed in sequence, and the mixture is ultrasonically treated to obtain the oxygen evolution catalyst slurry.

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