An ultrathin high-electricity-density long-endurance electrolytic water proton exchange membrane, a preparation method therefor and an application thereof

Abstract

This invention relates to the field of polymer materials technology, and particularly to an ultrathin, high-electrical-density, long-lasting proton exchange membrane for water electrolysis, its preparation method, and its applications. It comprises a PBI-H / PFSA composite framework membrane and a PBI-S crosslinked modified short-side-chain perfluorosulfonic acid polymer resin layer formed on and filling the composite framework membrane. The thickness of the composite framework membrane is 10-20 µm; the mass ratio of the composite framework membrane to the PBI-S crosslinked modified short-side-chain perfluorosulfonic acid polymer resin layer is (2-7):(85-97.6). In preparation, an oxide solid solution is first coated and dispersed with PBI-S, then added to a PBI-S modified PFSA solution to form a coating slurry, which is then coated and filled onto both sides of the composite framework membrane. The membrane is then dried, annealed, and crystallized to obtain the finished product. This membrane possesses ultrathinness, high mechanical strength, excellent chemical stability, and long lifespan, making it suitable for high-electrical-density PEM water electrolysis for hydrogen production.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to an ultrathin, high-electric-density, long-lasting proton exchange membrane for water electrolysis, its preparation method, and its application. Background Technology

[0002] To ensure sufficient mechanical strength and low gas permeation, commercial hydrogen production projects generally employ thick proton exchange membranes, typically ranging from 100 to 200 µm in thickness. Homogeneous membranes are predominantly over 125 µm thick, while reinforced membranes are approximately 80–10 µm thick; examples include Nafion™ N115 (approximately 127 µm homogeneous membrane), N117 (approximately 178 µm homogeneous membrane), or Fuma990 (approximately 100 µm reinforced membrane). Due to their thickness, these membranes are expensive, have low conductivity, and low electrolysis efficiency, resulting in high hydrogen production costs.

[0003] 50µm is considered a key thickness for PEMs in water electrolysis applications to optimize performance and cost. Operating at high current density (high electrical density) at this thickness can significantly improve electrolysis efficiency and substantially reduce proton exchange membrane costs, thereby lowering hydrogen production costs. Currently, there are commercial applications of 50µm PEMs in water electrolysis for hydrogen production (such as Nafion 212 and GoreSelect), but they are only suitable for low current density conditions; when the current density exceeds 2A / cm², the application is limited. 2 In practical applications, their lifespan is far shorter than that of proton exchange membranes with a diameter of 100µm or larger (below 4000 hours). Therefore, the high-electrical-density, long-durability 50µm PEM is still under continuous research and development and improvement as a proton exchange membrane for water electrolysis to produce hydrogen.

[0004] Chinese invention patent CN118016923A discloses a high-performance composite proton exchange membrane, its preparation method, and its application, belonging to the field of ion exchange membrane technology. This high-performance composite proton exchange membrane, with a thickness of 5-50 µm, is composed of perfluorosulfonic acid resin and an organic-cerium ion complex; wherein the amount of the organic-cerium ion complex added is 0.01 wt% to 5 wt% of the mass of the perfluorosulfonic acid resin. Compared with existing technologies, the organic-cerium ion complex prepared in this patent solves the problem of chemical degradation by hydroxyl radicals, improving the chemical stability and durability of the composite proton exchange membrane; however, its performance (such as hydrogen permeability and high electrical density lifetime) still has room for improvement. Summary of the Invention

[0005] The purpose of this invention is to provide an ultrathin, high-current-density, long-lasting proton exchange membrane for water electrolysis and its preparation method, so as to solve the problems of poor durability, low mechanical strength, short life and high cost of existing proton exchange membranes under thin-film and high-current-density operating conditions.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The first aspect of the present invention provides an ultrathin, high-electric-density, long-durability proton exchange membrane for water electrolysis, comprising a PBI-H / PFSA composite framework membrane and a PBI-S crosslinked modified short-side-chain perfluorosulfonic acid polymer resin layer formed on and filling the PBI-H / PFSA composite framework membrane, wherein the thickness of the PBI-H / PFSA composite framework membrane is 10~20µm; and the mass ratio of the PBI-H / PFSA composite framework membrane to the PBI-S crosslinked modified short-side-chain perfluorosulfonic acid polymer resin layer is (2~7):(85~97.6).

[0008] The PBI-H / PFSA composite framework membrane comprises the following raw material components in parts by weight:

[0009] PBI-H 100~200 servings;

[0010] 100 parts of short-side-chain perfluorosulfonic acid polymer resin;

[0011] The PBI-S crosslinked modified short-side-chain perfluorosulfonic acid polymer resin layer comprises the following raw material components in parts by weight:

[0012] 85-97.6 parts of short-side-chain perfluorosulfonic acid polymer resin;

[0013] Crosslinking agent PBI-S: 0.1~5 parts;

[0014] 0.1 to 1 part of gadolinium cerium oxide solid solution with PBI-S coating on the surface;

[0015] 0.1 to 1 part of cerium zirconium oxide solid solution with PBI-S coating on the surface;

[0016] 0.1 to 1 part of zirconium iridium oxide solid solution with PBI-S coating on the surface;

[0017] The gadolinium cerium oxide solid solution, the cerium zirconium oxide solid solution, and the zirconium iridium oxide solid solution coated with PBI-S all have a particle size ≤150nm.

[0018] Furthermore, based on 85 to 97.6 parts by weight of the short-side-chain perfluorosulfonic acid polymer resin, the weight of PBI-S used to form the PBI-S coating layer on any of the surfaces of the gadolinium cerium oxide solid solution, cerium zirconium oxide solid solution, or zirconium iridium oxide solid solution is independently 0.018 to 0.21 parts.

[0019] Furthermore, the gadolinium cerium oxide solid solution with PBI-S coating, the cerium zirconium oxide solid solution with PBI-S coating, and the zirconium iridium oxide solid solution with PBI-S coating are prepared by independently combining the corresponding oxide solid solutions with the PBI-S coating solution and removing the solvent.

[0020] Based on 100 parts by weight of the gadolinium cerium oxide solid solution, cerium zirconium oxide solid solution, or zirconium iridium oxide solid solution, the PBI-S coating solution comprises the following components:

[0021] PBI-S 1~10 servings;

[0022] DMAc 500~10000 copies;

[0023] 0.05~0.1 parts of PVP or CTAB.

[0024] Furthermore, the Ew of the short-side-chain perfluorosulfonic acid polymer resin is 670~1000 g / mol.

[0025] Furthermore, the crosslinking agent PBI-S has a molecular weight (Mw) of 1.6 × 10⁻⁶. 4 ~5×10 4 g / mol.

[0026] Furthermore, the PBI-S crosslinked modified short-side-chain perfluorosulfonic acid polymer resin layer is a continuous phase formed by curing the PBI-S crosslinked modified short-side-chain perfluorosulfonic acid polymer solution. The raw material of the PBI-S crosslinked modified short-side-chain perfluorosulfonic acid polymer solution includes the PBI-S crosslinked short-side-chain perfluorosulfonic acid polymer solution, which contains the following raw material components in parts by weight:

[0027] 600-3000 parts of short-side-chain perfluorosulfonic acid polymer resin;

[0028] 30 copies of PBI-S;

[0029] NaOH 14.4~33.6 parts;

[0030] Water 45.6~106.4 parts;

[0031] 700-1000 parts of ethanol;

[0032] DMA solution (50wt%) 30~100 parts;

[0033] DMAc 31~152 copies;

[0034] Isopropanol 425~23028 parts.

[0035] Furthermore, the PBI-H / PFSA composite skeleton membrane has a porosity of 70-90%, a tensile strength of 40-45 MPa, and a Young's modulus of 1.5-2.5 GPa.

[0036] Furthermore, the PBI-H / PFSA composite skeleton membrane is prepared by coaxial electrospinning, wherein the PFSA electrospinning solution is used as the shell layer solution and the polybenzimidazole sodium salt electrospinning solution is used as the core layer solution.

[0037] Furthermore, the polybenzimidazole sodium salt electrospinning solution comprises the following raw material components in parts by weight:

[0038] 30 copies of PBI-H;

[0039] NaOH 14.4~33.6 parts;

[0040] PVA 2.2~6.4 parts;

[0041] 0.4 to 3.2 parts of glutaraldehyde;

[0042] Water 45.6~106.4 parts;

[0043] DMAc 2.2~3.2 parts;

[0044] 484-761 parts of ethanol;

[0045] Furthermore, the weight-average molecular weight Mw of the PBI-H is 5 × 10⁻⁶. 4 ~10×10 4 g / mol.

[0046] Further, the PBI-H / PFSA composite framework membrane is prepared according to the following steps:

[0047] (S1) Dissolve PFSA in a solvent to obtain an electrospinning solution of PFSA;

[0048] (S2) Dissolve PBI-H powder in NaOH / PVA ethanol solution at high temperature and alkalize it to form polybenzimidazole sodium salt electrospinning solution;

[0049] (S3) Subsequently, the PBI-H / PFSA composite skeleton membrane is obtained by electrospinning with the PFSA electrospinning solution as the shell solution and the polybenzimidazole sodium salt electrospinning solution as the core solution using a coaxial spinneret.

[0050] Further, in step (S3), the voltage of the electrospinning is 18~25 kV, the flow rate is 0.02~0.04 mL / min, and the distance between the electrospinning and the rotating drum is 12~15 cm.

[0051] A second aspect of this invention provides a method for preparing an ultrathin, high-electric-density, long-lasting proton exchange membrane for water electrolysis, comprising the following steps:

[0052] (a) The gadolinium cerium oxide solid solution, cerium zirconium oxide solid solution and zirconium iridium oxide solid solution are added to an organic solvent containing PBI-S and dispersed to achieve coating, thereby obtaining their respective oxide solid solution dispersions.

[0053] (b) The oxide solid solution dispersion is subjected to solvent removal to obtain a PBI-S coated oxide solid solution mixture;

[0054] (c) The PBI-S coated oxide solid solution mixture is added to the PBI-S crosslinked short-side chain perfluorosulfonic acid polymer solution in proportion and dispersed to obtain a PBI-S crosslinked modified short-side chain perfluorosulfonic acid polymer casting coating film solution with coated solid solution dispersion.

[0055] (d) The cast coating solution is used to coat and fill the PBI-H / PFSA composite skeleton membrane and dried to form a film; then the cast coating solution is used to coat the other side of the PBI-H / PFSA composite skeleton membrane and dried to form a film; post-treatment is performed to remove residual solvent, and finally annealing and crystallization are performed to obtain a proton exchange membrane with a thickness of 45~55 µm.

[0056] Further, in step (b), the solvent removal is achieved by coating the solid solution dispersion onto the substrate and drying it. The coating method includes at least one of spin coating, blade coating, and spray coating. When spin coating is used, the solvent is first diffused at a low speed of 500-1000 rpm and then the excess solvent is spun off at 2000-4000 rpm. In step (d), the annealing crystallization temperature is 160-210°C and the annealing crystallization time is 10-60 min.

[0057] The third aspect of this invention provides the application of an ultrathin, high-electric-density, long-durability proton exchange membrane for water electrolysis in the preparation of a proton exchange membrane water electrolysis hydrogen production device.

[0058] Furthermore, the proton exchange membrane water electrolysis hydrogen production device can achieve a flow rate of not less than 2 A / cm. 2 It operates stably under current density.

[0059] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0060] This invention provides an ultrathin, high-current-density, long-lasting PEM proton exchange membrane for water electrolysis and its preparation method. The proton exchange membrane comprises a PBI-H / PFSA composite framework membrane and a resin layer formed on the surface of the composite framework membrane and permeating and filling its pores. The resin layer contains PBI-S crosslinked modified PFSA resin and a dispersed and fixed composite inorganic functional filler system, thereby achieving enhanced interfacial bonding and improved chemical stability.

[0061] This invention combines a three-component composite solid solution system (Gd-Ce, Ce-Zr, and Zr-Ir oxide solid solutions) with a PBI-S coating technique. From a chemical protection mechanism perspective, the Zr-Ir solid solution promotes the stable decomposition / disproportionation of hydrogen peroxide (H2O2) under strong oxidizing and high-potential environments, reducing the precursor source for peroxide conversion to free radicals; Gd-Ce relies on oxygen vacancies and Ce... 3+ / Ce 4+ A reversible redox cycle captures and transforms reactive free radicals such as ·OH and ·OOH. Both work synergistically to cover the key degradation pathway of "peroxide-free radicals," and the superimposed PBI-S crosslinking network provides confinement and anchoring effects on the filler, achieving dual chemical protection of "in-situ free radical inhibition / scavenging + filler loss inhibition," thereby reducing the concentration of free radicals within the membrane and slowing down the fluoride ion release rate (FER).

[0062] From the perspective of structural and mechanical strengthening mechanisms, this invention modifies PFSA resin with PBI-S to form a stable ionic crosslinking network within the resin layer. This network couples with the PBI-H / PFSA composite framework membrane, which has high porosity and high modulus, providing anisotropic support for the ultrathin film and suppressing swelling. This, in turn, improves the tensile strength and dimensional stability of the membrane in the MD / TD direction, and reduces the risk of physical damage caused by pressure difference and deformation during long-term operation.

[0063] In summary, the synergistic effect of the aforementioned chemical protection and mechanical reinforcement enables the proton exchange membrane of this invention to achieve a performance of ≥2 A / cm². 2 Under high current density conditions, it can simultaneously maintain low gas cross-permeability (oxygen-hydrogen index) (e.g., H2 cross-permeation decreases towards the oxygen side), relatively stable voltage performance, and good mechanical integrity. Under predetermined operating conditions, its service life can reach or approach the service life level of existing commercial proton exchange membranes of approximately 125 µm, thus providing key membrane material support for the next generation of high-performance, low-energy PEM water electrolysis hydrogen production systems. Attached Figure Description

[0064] The following sections will describe some specific embodiments of the invention in detail by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or portions. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0065] Figure 1 This is a schematic diagram of the structure of the ultrathin, high-electric-density, long-lasting proton exchange membrane for water electrolysis provided in this invention;

[0066] Figure 2 This is a scanning electron microscope image of the gadolinium cerium oxide solid solution provided in this invention;

[0067] Figure 3 This is a scanning electron microscope image of the zirconium iridium oxide solid solution provided in this invention;

[0068] Figure 4 This is a scanning electron microscope image of the cerium zirconium oxide solid solution provided in this invention;

[0069] The accompanying drawings are described below:

[0070] 1. PBI-H / PFSA composite skeleton membrane; 2. PBI-S crosslinked modified short side chain perfluorosulfonic acid polymer resin layer. Detailed Implementation

[0071] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0072] This example provides an ultrathin, high-electric-density, long-lasting proton exchange membrane for water electrolysis, with a thickness of 45-55 µm, preferably 50 µm. The proton exchange membrane comprises a PBI-H / PFSA composite framework membrane and a PBI-S crosslinked modified short-side-chain perfluorosulfonic acid polymer resin layer 2 formed on and filled with the PBI-H / PFSA composite framework membrane 1 (e.g., ...). Figure 1 As shown), the thickness of the PBI-H / PFSA composite skeleton membrane 1 is 10~20µm; the mass ratio of the PBI-H / PFSA composite skeleton membrane 1 to the PBI-S crosslinked modified short side chain perfluorosulfonic acid polymer resin layer 2 is (2~7):(85~97.6).

[0073] PBI-H / PFSA composite framework membrane 1 comprises the following raw material components in parts by weight:

[0074] PBI-H 100~200 servings;

[0075] 100 parts of short-side-chain perfluorosulfonic acid polymer resin.

[0076] The PBI-S crosslinked modified short-side-chain perfluorosulfonic acid polymer resin layer 2 comprises the following raw material components in parts by weight:

[0077] 85-97.6 parts of short-side-chain perfluorosulfonic acid polymer resin;

[0078] Crosslinking agent PBI-S: 0.1~5 parts;

[0079] 0.1 to 1 part of gadolinium cerium oxide solid solution with PBI-S coating on the surface;

[0080] 0.1 to 1 part of cerium zirconium oxide solid solution with PBI-S coating on the surface;

[0081] 0.1 to 1 part of zirconium iridium oxide solid solution with PBI-S coating on the surface;

[0082] The particle size of all three types of coated oxide solid solutions is ≤150 nm.

[0083] Based on 85 to 97.6 parts by weight of short-side-chain perfluorosulfonic acid polymer resin, the weight of PBI-S used to form a PBI-S coating layer on any of the surfaces of gadolinium cerium oxide solid solutions, cerium zirconium oxide solid solutions, or zirconium iridium oxide solid solutions is independently 0.018 to 0.21 parts.

[0084] Gadolinium cerium oxide solid solution with PBI-S coating, cerium zirconium oxide solid solution with PBI-S coating, and zirconium iridium oxide solid solution with PBI-S coating are prepared by independently combining the corresponding oxide solid solutions with PBI-S spin-coating solution.

[0085] Based on 100 parts by weight of gadolinium cerium oxide solid solution, cerium zirconium oxide solid solution, or zirconium iridium oxide solid solution, the above PBI-S spin-coating solution comprises the following components:

[0086] PBI-S 1~10 servings;

[0087] DMAc 500~10000 copies;

[0088] 0.05~0.1 parts of PVP or CTAB.

[0089] Gadolinium cerium oxide solid solution, cerium zirconium oxide solid solution, and zirconium iridium oxide solid solution can be commercially available, or they can be made in-house using the following methods.

[0090] The preparation of gadolinium cerium oxide solid solutions mainly includes the following steps:

[0091] Add Gd salt (Gd(NO3)3·6H2O, purity >99%) and Ce salt (Ce(NO3)3·6H2O, purity >99%) to a water and alcohol mixture (volume ratio 1~3:1) (Gd to Ce molar ratio of 0.2:0.8 to 0.5:0.5, total salt concentration (Gd+Ce) of 0.01~0.1M (preferably 0.05 M)). Add stabilizers such as PVP (polyvinylpyrrolidone, 0.01~0.05 wt% of total salt) or CTAB (0.01~0.03 wt% of total salt) to prevent solid solution aggregation. Adjust the pH to 7~9 (using 0.1M NaOH to optimize reduction efficiency) and stir (300~500 rpm, 30 min) until clear. Sonicate disperse (50~100 W, 10 min) to remove bubbles.

[0092] The solution was placed in an autoclave, and ultrasonic hydrolysis / nucleation was promoted and particle size was controlled (ultrasonic reactor (probe type or bath type, 20~40 kHz, preferably 28 kHz; power 100~500 W, preferably 200~300 W); probe diameter 5~10 mm, immersed in solution 3~5 cm, ultrasonic at 50~80℃ (20~40 kHz, ultrasonic power 100~500 W, time 30~60 min)); after the reaction, centrifugation (8000~10000 rpm, 10 min) was used to separate the Gd-Ce oxide solid solution, and the solid solution was washed three times with DMF / water (volume ratio 1:1) to remove residual salts. The solid solution was then vacuum dried (80℃, <10 Pa, 4~6 h) or freeze-dried (-50℃, 12 h) to prevent agglomeration.

[0093] The preparation of cerium-zirconium oxide solid solutions mainly includes the following steps:

[0094] In a high-pressure autoclave, using a polyol (such as ethylene glycol) as a solvent, Ce salt (cerium nitrate (Ce(NO3)3·6H2O, purity >99%)) and Zr salt (zirconium nitrate (Zr(NO3)4·5H2O, purity >99%)) are mixed (Ce / Zr molar ratio is 0.2~0.5), with a total Ce+Zr salt concentration of 0.05~0.2M (preferably 0.1M); PVP (0.01~0.05wt% of total salt) is added as a dispersant to prevent agglomeration; the pH is adjusted to 6~8 (using 0.1M NaOH to optimize hydrolysis), and the mixture is stirred (300~500 rpm, 30 min) until clear, and then ultrasonically dispersed (power 100~150 W, 10 min) to remove bubbles.

[0095] The solution was placed in an autoclave, sealed, and heated (temperature 180~250℃, pressure 5~10 MPa, time 4~12h). Ethylene glycol was used as a reducing agent to form a mesoporous solid solution without a template. The solution was allowed to cool naturally to room temperature to avoid cracking caused by rapid cooling. The cerium zirconium oxide solid solution was separated by centrifugation (8000~12000 rpm, 10~15 min) and washed 3~5 times with ethanol / water (volume ratio 1:1) to remove residual salts and ethylene glycol. The solution was then vacuum dried (80~100℃, <10 Pa, 4~6 h) or freeze-dried (-50℃, 12~24h) to prevent agglomeration.

[0096] The preparation of zirconium-iridium oxide solid solutions mainly includes the following steps:

[0097] Ethylene glycol (EG, analytical grade, >99.5%) was used as the main solvent, and deionized water (10-20 vol%) was added to adjust solubility and viscosity. Total solvent usage: 50-500 mL / batch. The ethylene glycol:water ratio was 4:1 to 9:1 (preferably 8:2, i.e., 64 mL EG + 16 mL H2O). Zirconium oxychloride (ZrOCl2·8H2O), purity >99%, and iridium nitrate Ir(NO3)3 (0.05 M total metal concentration, Zr:Ir = 0.8:0.2 (molar ratio)) were used; PVP (0.01-0.03 wt% of total salt) was added as a dispersant; the pH was adjusted to 9-10 with 0.1 M NaOH (optimized for hydrolysis); stirring (300-500 rpm, 30 min) was performed until clear, and ultrasonic dispersion (100-150 W, 10 min) was used to remove bubbles.

[0098] The solution was placed in an autoclave, and Zr salt (ZrOCl2) and Ir salt (Ir(NO3)3) were mixed and heated (temperature 120~200℃, pressure 5~10MPa, ultrasonic power 200~400W, time 2~10h) with the assistance of an ultrasonic reactor (probe type, 20~40 kHz, power 200~400W, time 2~10h) to form a mesoporous solid solution without a template. The zirconium iridium oxide solid solution was separated by centrifugation (10000~15000 rpm, 10~15 min), and washed 3~5 times with ethanol / water (volume ratio 1:1) to remove residual salt and ethylene glycol. Vacuum drying (80~100℃, <10 Pa, 4~6 h) or freeze drying (-50℃, 12~24 h) was performed to prevent agglomeration.

[0099] The Ew of short-side-chain perfluorosulfonic acid polymer resins is 670~1000g / mol. Commercially available Aquivion D72-25BS, Aquivion D79-25BS, 3Minomers solutions, or short-branched resins such as FSA-PW-1890, Aquivion® PW98 resin, and 3Minomers series resins can be used.

[0100] The crosslinking agent PBI-S has a molecular weight (Mw) of 1.6 × 10⁻⁶. 4 ~5×10 4 g / mol, commercially available 5200P, Celazole® PBI resin powder, etc. can be used.

[0101] The PBI-S crosslinked modified short-side-chain perfluorosulfonic acid polymer resin layer is a continuous phase formed by curing the PBI-S crosslinked modified short-side-chain perfluorosulfonic acid polymer solution. The raw material of the PBI-S crosslinked modified short-side-chain perfluorosulfonic acid polymer solution includes the PBI-S crosslinked short-side-chain perfluorosulfonic acid polymer solution, which contains the following raw material components in parts by weight:

[0102] 600-3000 parts of short-side-chain perfluorosulfonic acid polymer resin;

[0103] 30 copies of PBI-S;

[0104] NaOH 14.4~33.6 parts;

[0105] Water 45.6~106.4 parts;

[0106] 700-1000 parts of ethanol;

[0107] DMA solution (50wt%) 30~100 parts;

[0108] DMAc 31~152 copies;

[0109] Isopropanol 425~23028 parts.

[0110] Specifically, the preparation method of the above-mentioned PBI-S crosslinked short-side-chain perfluorosulfonic acid polymer solution is as follows:

[0111] (1) Dissolve NaOH (14.4g~33.6g) in water (45.6g~106.4g) in a container, then add 700g~1000g of ethanol to form a NaOH ethanol solution; transfer it to an autoclave, add 30g of PBI-S, and autoclave at high temperature and high pressure (160~180℃, 4kgf / cm). 2 ~40 kgf / cm 2Keep warm and stir for 3~12 hours, then filter to form a clear PBINa solution (polybenzimidazole sodium salt solution).

[0112] (2) Mix 5600~10000g of ethanol with the sodium polybenzimidazole solution in step (1) until homogeneous. Then, add 30~100g of 50% DMA (volume ratio) aqueous solution under stirring and ultrasonic conditions. Immediately afterward, add 5%~15% PFSA solution and mix until homogeneous (so that the mass ratio of PBI-S to PFSA is 0.1~5:100, and the mixing is carried out by mechanical stirring and ultrasonic dispersion). Use H ion exchange resin (hydrogen-type strong acid cation exchange resin) to adjust the pH of the solution to 1~3. Finally, select solvents such as ethanol, propanol, DMAc, DMF, NMP or DMSO according to the state of the membrane for distillation (adjust the type and ratio of solvents according to whether cracking and wetting effect). Filter to ensure no impurities and no crystal points. Vacuum and gently concentrate to obtain a PBI-S cross-linked short side chain perfluorosulfonic acid polymer solution with a solid content of 5~40%.

[0113] The PBI-H / PFSA composite skeleton membrane has a porosity of 70-90%, a tensile strength of 40-45 MPa, and a Young's modulus of 1.5-2.5 GPa.

[0114] The PBI-H / PFSA composite skeleton membrane was prepared by coaxial electrospinning, with PFSA electrospinning solution as the shell solution and polybenzimidazole sodium salt electrospinning solution as the core solution.

[0115] The sodium polybenzimidazole electrospinning solution contains the following raw material components in parts by weight:

[0116] 30 copies of PBI-H;

[0117] NaOH 14.4~33.6 parts;

[0118] PVA 2.2~6.4 parts;

[0119] 0.4 to 3.2 parts of glutaraldehyde;

[0120] Water 45.6~106.4 parts;

[0121] DMAc 2.2~3.2 parts;

[0122] 484-761 parts of ethanol;

[0123] Furthermore, the weight-average molecular weight Mw of the PBI-H is 5 × 10⁻⁶. 4 ~10×10 4 g / mol.

[0124] The PBI-H / PFSA composite framework membrane was prepared according to the following steps:

[0125] (S1) Dissolve PFSA in a solvent to obtain an electrospinning solution of PFSA;

[0126] (S2) Dissolve PBI-H powder in NaOH / PVA ethanol solution at high temperature and alkalize it to form polybenzimidazole sodium salt electrospinning solution;

[0127] (S3) Subsequently, a coaxial spinneret was used to electrospin the PBI-H / PFSA composite skeleton membrane with the PFSA electrospinning solution as the shell solution and the polybenzimidazole sodium salt electrospinning solution as the core solution.

[0128] Specifically, it can be as follows:

[0129] (S1) Add 100~1000ml of water and 30g of PFSA to the autoclave, and pressurize at high temperature and high pressure (160~180℃, 4kgf / cm²). 2 ~40 kgf / cm 2 The PFSA solution is dispersed by incubation for 3-12 hours, then distilled to obtain a PFSA membrane solution with a solid content of 5-40%. Finally, it is filtered to ensure that there are no impurities and no crystal points. The PFSA can be PFSA perfluorosulfonic acid resin powder (such as PFSA-PW-1890, Aquivion PW98, 3M Inomers resin, etc.) or commercially available PFSA solution (such as Aquivion D79-25BS solution with a resin mass concentration of 5-20%; 3M Inomers membrane solution).

[0130] (S2) Dissolve NaOH (14.4g~33.6g) in water (45.6g~106.4g) in a container, then add 700g~1000g of ethanol to form a NaOH ethanol solution; then add polyvinyl alcohol (PVA with a molecular weight of 20,000~100,000, 0.5~1wt% of the NaOH ethanol solution) to thicken; transfer it to an autoclave, add 30g of PBI-H (polybenzimidazole, such as U60, U70, etc., with a molecular weight of 5×10). 4 ~10×10 4 g / mol), under high temperature and high pressure (160~180℃, 4kgf / cm³), 2 ~40 kgf / cm 2 Keep warm and stir for 3-12 hours, then distill and concentrate, and add glutaraldehyde pre-crosslinking agent (0.1-0.5 wt% of the concentrate to enhance stability). Adjust the solid content to 5-10% with an appropriate amount of DMAc solvent, and filter to form a clear PBINa electrospinning solution (i.e., polybenzimidazole sodium salt electrospinning solution).

[0131] (S3) Subsequently, a coaxial spinneret (i.e., a dual-channel spinneret with an inner diameter of 0.3~0.5 mm, an outer diameter of 0.6~0.8 mm, and a wall thickness of 0.2~0.3 mm for the core layer spinneret; an inner diameter of 0.8~1.0 mm, an outer diameter of 1.2~1.5 mm, and a wall thickness of 0.2~0.3 mm for the shell layer spinneret; and a coaxial gap of 0.1~0.2 mm) was used to electrospin the PBI-H / PFSA composite skeleton membrane with PFSA electrospinning solution as the shell layer solution and polybenzimidazole sodium salt electrospinning solution as the core layer solution. The electrospinning parameters are: voltage 18~25 kV, flow rate 0.02~0.04 mL / min (when using a coaxial spinneret, the internal / external flow rate ratio is 1:1~2:1), collected on a rotating drum (the distance between the rotating drum and the electrospinning is 12~15 cm), and spun for 2~4 h to achieve a thickness of 10~20 μm (the diameter of the obtained single fiber is about 150~350 nm, and the core PBI-H part is about 80~260 nm).

[0132] This example also provides a method for preparing an ultrathin, high-electric-density, long-durability proton exchange membrane for water electrolysis, comprising the following steps:

[0133] (a) Gadolinium cerium oxide solid solution, cerium zirconium oxide solid solution and zirconium iridium oxide solid solution are added to an organic solvent containing PBI-S and ultrasonically dispersed to achieve coating, thereby obtaining their respective oxide solid solution dispersions.

[0134] (b) In a clean room, the oxide solid solution dispersion is spin-coated onto the substrate, and the organic solvent is removed to obtain a PBI-S coated oxide solid solution mixture;

[0135] (c) The PBI-S coated oxide solid solution mixture is added to the PBI-S cross-linked short-side chain perfluorosulfonic acid polymer solution in proportion and ultrasonically dispersed to obtain a PBI-S cross-linked modified short-side chain perfluorosulfonic acid polymer casting film solution with coated solid solution dispersion.

[0136] (d) Coat and fill the PBI-H / PFSA composite skeleton membrane with the cast coating solution and dry it to form a film; then coat the other side of the PBI-H / PFSA composite skeleton membrane with the cast coating solution and dry it to form a film; perform post-treatment to remove residual solvent, and finally anneal and crystallize to obtain a proton exchange membrane with a thickness of 45~55 µm.

[0137] In step (a), the PBI-S coating solution is prepared according to the following steps: 3g of PBI-S powder (same as crosslinking agent PBI-S) is added to 300g of DMAC (N,N-dimethylacetamide), and stabilizers PVP (polyvinylpyrrolidone, 0.03g~0.15g) or CTAB (hexadecyltrimethylammonium bromide, 0.03g~0.15g) are added and subjected to high temperature and high pressure (80~200℃ (preferably 160~200℃), 1kgf / cm²). 2 ~40kgf / cm 2 Keep in a high-pressure autoclave for 3-12 hours; finally, add DMAC to dilute to 0.1-0.2% solid content and filter to form a clear PBI-S coated solution (i.e., polybenzimidazole sodium salt coated solution).

[0138] In step (b), the solid solution dispersion is first diffused at a low speed of 500-1000 rpm during spin coating, and then excess solvent is spun off at a speed of 2000-4000 rpm; in step (d), the annealing crystallization temperature is 160-210℃ and the annealing crystallization time is 10-60 min.

[0139] The relevant testing methods involved in this example are as follows:

[0140] (1) Thickness (μm): GB / T 4593 (Determination of thickness of plastic film) or GB / T 6672 (Determination of thickness of plastic film and sheet); Method: Measured by micrometer / thickness gauge, with an accuracy of 0.001 mm.

[0141] (2) Conductivity @ 80℃ water (S / cm): IEC TS 62282-10-201 (Test of fuel cell / water electrolysis cell); Method: AC impedance method (EIS), ionic conductivity is measured in deionized water at 80℃.

[0142] (3) Hydrogen permeability in oxygen (cm) 3 / m 2 •24h·Pa): ISO 15105-1 (Gas permeability of plastic films and sheets), ASTM D1434 (Gas permeability); Method: Differential pressure method / coulometric method, record the hydrogen permeation rate.

[0143] (4) Tensile strength (MPa): GB / T 1040.3 (test for tensile properties of plastics), ASTM D882 (test for tensile properties of films); Method: standard dumbbell-shaped specimen, tensile rate 50 mm / min.

[0144] (5) Initial voltage @3A / cm 280℃ (V): EC 62282-2 (PEM electrolyzer performance); Method: After MEA (membrane electrode assembly), it is tested at 80℃ and 3 A / cm. 2 The steady-state voltage was measured.

[0145] (6) Hydrogen in oxygen @ 2MPa, 2A / cm 2 (%): ISO 14687 (Hydrogen Fuel Quality Standard) / IEC 62282-2; Method: Determine the hydrogen cross-permeability ratio under hydrogen / oxygen bipolar conditions. At 2 MPa, 2 A / cm 2 Hydrogen gas was collected under certain conditions, and the oxygen impurity content was detected by gas chromatography.

[0146] (7) Durability @ 3A / cm 2 80℃ All water: IEC 62282-2 / DOE Hydrogen Program Test Protocol; Method: 80℃, 3 A / cm 2 It operates at a constant voltage until the voltage decays to the threshold (25µv / h).

[0147] (8) Voltage after durability @3A / cm 2 80℃ (V): Same as above, record the voltage retention rate after running for several hours.

[0148] (9) After durability testing, hydrogen in oxygen at 2MPa and 2A / cm 2 (%): Same as above, test the permeability after running for a period of time.

[0149] (10) Voltage decay @5000h (µV / h): DDOE PEMWE Durability Protocol, Method: Run for 5000h, linearly fit the voltage decay rate over time, if less than 5000h, use the actual hours.

[0150] (11) HFR@80℃ (mΩ·cm) 2 EIS method, IEC 62282-2; Method: High-frequency impedance (typically 1~10kHz), characterizing ohmic resistance.

[0151] (12) FER Fluorine release (μmol·m -2 ·h -1 ): ASTM D7359 (Determination of fluoride by ion chromatography), Method: After durability testing, water samples are collected and the amount of fluoride released is determined by ion chromatography (IC).

[0152] (13) IEC retention rate (%): ASTM E2049 (ion exchange capacity), method: acid-base titration to determine IEC, and compare retention rate before and after aging.

[0153] (14) Water absorption (%): GB / T 1034 (Determination of water absorption rate of plastics), ASTM D570 (Water absorption rate of plastics), Method: Immerse the sample in water for 24 hours and weigh it to compare the mass before and after water absorption.

[0154] (15) In-plane expansion (%): Custom method or ASTM D1204 (heat shrinkage / expansion of plastics), method: measure dimensional changes before and after immersion in water or before and after heating.

[0155] (16) ICP metal leaching (ppb): ASTM D5673 (ICP-MS / ICP-OES determination of metal elements), method: immersion sample, metal concentration is detected by ICP.

[0156] The present invention will be further illustrated below through specific embodiments: Example 1

[0157] This embodiment provides an ultrathin, high-electric-density, long-durability proton exchange membrane for water electrolysis and its preparation method, as detailed below:

[0158] (1) Preparation of gadolinium cerium oxide solid solution

[0159] Add 4.5 g of Gd salt (Gd(NO3)3·6H2O, purity >99%, 0.01 mol) and 17.4 g of Ce salt (Ce(NO3)3·6H2O, purity >99%, 0.04 mol) to a water and alcohol mixture (1:1, 1 L), and add 4.4 mg of stabilizer PVP (polyvinylpyrrolidone); adjust the pH to 7-9 with 0.1 M NaOH; stir (300 rpm, 30 min) until clear, and ultrasonically disperse (50 W, 10 min) to remove bubbles.

[0160] The solution is placed in a reactor and subjected to ultrasonic treatment at 50-80°C (20-40 kHz ultrasonic power 200W, probe diameter 10 mm, immersed in the solution 3-5 cm; within this range, the performance of the product is basically unaffected, the same below) using an ultrasonic reactor (probe type, 28 kHz, 200W ultrasonic power, 30-60 min) to promote hydrolysis and nucleation, so that the aforementioned precursor is converted into an oxide solid solution, forming a Gd-Ce oxide solid solution.

[0161] After the reaction, the Gd-Ce oxide solid solution was separated by centrifugation (8000~10000 rpm, 10 min); residual salts were removed by washing three times with a mixed solvent of DMF and water (1:1 volume ratio); and vacuum drying (80℃, ≤10 Pa, 4~6 h) was performed to prevent agglomeration (electron microscopy particle size ≤150 nm). Figure 2 (As shown).

[0162] (2) Preparation of cerium zirconium oxide solid solution

[0163] In an autoclave, using 300 mL of polyol (ethylene glycol) as a solvent, 2.61 g of Ce salt (cerium nitrate (Ce(NO3)3·6H2O, purity >99%), 0.02 mol) and 10.31 g of Zr salt (zirconium nitrate (Zr(NO3)4·5H2O, purity >99%), 0.08 mol) were mixed; 3.24 mg of PVP (0.025 wt% of total salt) was added as a dispersant; the pH was adjusted to 6-8 (using 0.1 M NaOH); the mixture was stirred (300-500 rpm, 30 min) until clear, and then ultrasonically dispersed (100 W, 10 min) to remove bubbles.

[0164] The solution was placed in an autoclave, sealed, and heated (180℃, 5 MPa, 12h) using ethylene glycol as a reducing agent to form a cerium-zirconium oxide solid solution. The solution was then allowed to cool naturally to room temperature (2-3h) to avoid rapid cooling that could cause cracking. The cerium-zirconium oxide solid solution was separated by centrifugation (8000-12000 rpm, 10-15 min); washed 3-5 times with ethanol / water (1:1 volume ratio) to remove residual salts and ethylene glycol; and then vacuum dried (80-100℃, ≤10 Pa, 4-6h). Electron microscopy showed a particle size ≤150nm (e.g., ...). Figure 4 (As shown).

[0165] (3) Preparation of zirconium iridium oxide solid solution

[0166] Ethylene glycol (EG, analytical grade, >99.5%) was used as the main solvent, and deionized water (20 vol%) was added to adjust solubility and viscosity; total solvent volume: 300 mL / batch (laboratory scale, suitable for 500 mL autoclave); at this time, the ethylene glycol:water ratio was 4:1 (i.e., 240 mL EG + 60 mL H2O); 3.87 g zirconium oxychloride (ZrOCl2·8H2O, purity >99%) and 1.13 g iridium nitrate Ir(NO3)3 were added; then 10 mg PVP (0.02 wt% of total salt) was added as a dispersant; the pH was adjusted to 9-10 with 0.1 M NaOH to optimize hydrolysis; stirring (300-500 rpm, 30 min) was carried out until clear; ultrasonic dispersion (100 W, 10 min) was used to remove bubbles.

[0167] The solution was placed in an autoclave, and Zr salt (ZrOCl2) and Ir salt (Ir(NO3)3) were mixed and heated (temperature 150℃, pressure 8MPa, ultrasonic power 300W, time 5h) with the assistance of an ultrasonic reactor (probe type, 28 kHz, 200~300 W) to form a mesoporous solid solution without a template. The solid solution was separated by centrifugation (10000~15000 rpm, 10~15 min), and washed 3~5 times with ethanol / water (1:1) to remove residual salt and ethylene glycol. Vacuum drying was performed (80~100℃, <10 Pa, 4~6 h). Electron microscopy showed a particle size <150nm (e.g., ...). Figure 3 (As shown).

[0168] (4) Preparation of gadolinium cerium oxide solid solution with PBI-S coating, cerium zirconium oxide solid solution with PBI-S coating and zirconium iridium oxide solid solution with PBI-S coating

[0169] (4a) 3g of PBI-S powder (GAZOLE™ 5200P Celazole® (Mw=52000g / mol)) was added to 300g of DMAc, and 0.10g of PVP (polyvinylpyrrolidone) stabilizer was added; the mixture was subjected to high temperature and high pressure (160℃, 10kgf / cm) 2 Keep warm for 5 hours, then add DMAc to dilute to 0.1% solid content and filter to form a clear PBINA coated solution (i.e., polybenzimidazole sodium salt coated solution).

[0170] (4b) Gadolinium cerium oxide solid solution (1g), cerium zirconium oxide solid solution (1g) and zirconium iridium oxide solid solution (1g) were ultrasonically dispersed and mixed with 30 mL of 0.1% PBINa-coated solution to obtain solid solution dispersions (the mass ratio of each solid solution to PBI-S was approximately 20:1); then, in a clean room, each solid solution dispersion was spin-coated onto a substrate (first diffused at a low speed of 600 rpm for 10s, then spin-coated at a speed of 2000 rpm for 20s) to remove organic solvents and obtain PBI-S-coated solid solutions.

[0171] (5) Preparation of PFSA membrane solution

[0172] Add 30g of PFSA (brand name 3M 700EW) to 170ml of water and pressurize under high temperature and pressure (160℃, 10kgf / cm²). 2 The PFSA solution was dispersed by heat treatment for 5 hours, and then distilled to obtain a PFSA membrane solution with a solid content of 15%. Finally, the solution was filtered to ensure that there were no impurities and no crystal points.

[0173] (6) Preparation of PBI-H / PFSA composite framework membrane

[0174] (6a) Dissolve 30g of PFSA (3M 700EW) in 170ml of water and pressurize under high temperature and pressure (160℃, 10kgf / cm²). 2 The PFSA solution was dispersed by keeping it warm for 5 hours, and then distilled to obtain a PFSA membrane solution with a solid content of 15% (i.e., PFSA electrospinning solution). Finally, it was filtered to ensure that there were no impurities and no crystal points.

[0175] (6b) Dissolve 14.4g NaOH in 45.6g water in a container, then add 700g ethanol to form a NaOH ethanol solution; add 3.8g polyvinyl alcohol (PVA-0588) for thickening; transfer it to an autoclave, add 30g PBI-H (polybenzimidazole, Celazole® U-70 (M W =78000 g / mol), in a high-temperature and high-pressure autoclave (160℃, 10 kgf / cm³). 2 Keep warm and stir for 3 hours, concentrate to 300g and add 0.6g glutaraldehyde pre-crosslinking agent (0.2wt% of the concentrate); mix with 270g DMAc solvent until the solid content is 5%, filter to form a clear PBINA electrospinning solution (i.e., polybenzimidazole sodium salt electrospinning solution).

[0176] (6c) Using a coaxial spinneret (core layer spinneret inner diameter 0.3 mm, outer diameter 0.6 mm, wall thickness 0.3 mm; shell layer spinneret inner diameter 1.0 mm, outer diameter 1.2 mm, wall thickness 0.2 mm; coaxial gap 0.2 mm), electrospinning was performed with PFSA electrospinning solution as shell layer solution and polybenzimidazole sodium salt electrospinning solution as core layer solution to obtain PBI-H / PFSA composite skeleton (thickness 10 µm, porosity 70%, tensile strength 40 MPa, Young's modulus 1.5 GPa).

[0177] (7) Preparation of crosslinking agent PBI-S solution

[0178] Dissolve 14.4g of NaOH in 45.6g of water in a container, then add 700g of ethanol to form a NaOH ethanol solution; then add 18.4g of PBI-S (polybenzimidazole, GAZOLE™ 5200P Celazole®) to the solution. W =52000g / mol), in an autoclave (160℃, 10kgf / cm³). 2 Keep warm and stir for 3 hours, then filter to form a clear PBINa crosslinking agent (i.e., polybenzimidazole sodium salt crosslinking agent solution); the solid content is about 2.8%.

[0179] (8) Preparation of PBI-S cross-linked short-side-chain perfluorosulfonic acid polymer solution

[0180] (8a) Dissolve 14.4 g of NaOH in 45.6 g of water in a container, then add 700 g of ethanol to form a NaOH ethanol solution; then add 18.4 g of PBI-S (polybenzimidazole, GAZOLE™ 5200P Celazole®) to it. W =52000g / mol), in an autoclave (160℃, 10kgf / cm³). 2 The mixture was kept at a constant temperature and stirred for 3 hours, then filtered to form a clear PBINa crosslinking agent solution (i.e., a polybenzimidazole sodium salt crosslinking agent solution); the solid content was approximately 2.8%.

[0181] (8b) Mix 6032g of ethanol with the polybenzimidazole sodium salt crosslinking agent solution from the previous step until homogeneous. Then, add 50g of 50% DMA (volume ratio) aqueous solution while stirring and sonicating. Immediately afterward, add 1152g of 15% (solid content) PFSA solution (refer to the aforementioned self-made solution) and mix until homogeneous (so that the mass ratio of PBI-S to PFSA is approximately 10:100). Adjust the pH of the solution to 1-3 using H ion exchange resin (hydrogen-form strong acid cation exchange resin), filter to ensure no impurities and no crystal points, and gently concentrate under vacuum to obtain a 10% solid content PBI-S crosslinked short-side chain perfluorosulfonic acid polymer solution.

[0182] (9) Preparation of ultrathin, high-electric-density, long-durability proton exchange membranes for water electrolysis

[0183] (9a) Gadolinium cerium oxide solid solution (0.3g), cerium zirconium oxide solid solution (0.3g) and zirconium iridium oxide solid solution (0.3g) were added to an organic solvent (1g solid content) containing crosslinking agent PBI-S and ultrasonically dispersed to obtain a solid solution dispersion.

[0184] (9b) Spin-coating the solid solution dispersion onto the substrate in a clean room (diffusion of the solid solution dispersion at a low speed of 800 rpm during spin coating, followed by removal of excess solvent at a speed of 3000 rpm) to remove organic solvent and obtain a PBI-S coated solid solution mixture.

[0185] (9c) Add the PBI-S coated solid solution mixture to the PFSA solution (using the PBI-S crosslinked short side chain perfluorosulfonic acid polymer from step (8) (solution, 951g, solid content 95.1g)) and ultrasonically disperse to obtain spin coating slurry.

[0186] (9d) Place the PBI-H / PFSA composite skeleton membrane (10µm) on the surface of the PI membrane, coat the PBI-H / PFSA composite skeleton membrane with spin coating slurry (solution) and fill the PBI-H / PFSA composite skeleton membrane; after the spin coating slurry (solution) has cured, peel the PBI-H / PFSA composite skeleton membrane off the PI membrane, flip it 180° and place it on the surface of the PI membrane, continue to coat the PBI-H / PFSA composite skeleton membrane with spin coating slurry (solution), dry to form a film and anneal and crystallize (160℃) to obtain the proton exchange membrane (the mass ratio of PBI-H / PFSA composite skeleton membrane to the dried finished membrane is 1:11).

[0187] The prepared ultrathin, high-electrical-density, long-lasting proton exchange membrane for water electrolysis was tested, and its performance is as follows: membrane thickness 49.9 µm, conductivity 0.229 S / cm, HFR@80℃ 88 mΩ·cm 2 The actual durability test was completed after 10542 hours of operation. The initial voltage was 1.678V, with a voltage decay of 18µV / h. The strength was 40.0 MPa. After durability testing, the hydrogen content in the oxygen (hydrogen permeation) was 0.40%, and the fluorine release from the FER was 0.8µmol·m³. -2 ·h -1 . Example 2

[0188] This embodiment provides an ultrathin, high-electric-density, long-lasting proton exchange membrane for water electrolysis and its preparation method, which is basically the same as that in Example 1, except that: 925g of PFSA solution (92.5g of solid content), 0.5g of gadolinium cerium oxide solid solution, 0.5g of cerium zirconium oxide solid solution, 0.5g of zirconium iridium oxide solid solution, 4g of PBI-H fiber, and 2g of crosslinking agent PBI-S (solid content).

[0189] An ultrathin, high-electrical-density, long-durability proton exchange membrane for water electrolysis was tested, and its performance is as follows: membrane thickness 50.2 µm, conductivity 0.210 S / cm, HFR@80℃ 95 mΩ·cm 2 The system operated for 11,278 hours before stopping. Initial voltage was 1.692V, voltage decay was 16µV / h, strength was 42.0MPa, and after durability testing, hydrogen permeation in oxygen was 0.39%, and fluorine release via FER was 0.7µmol·m³. -2 ·h -1 . Example 3

[0190] This embodiment provides an ultrathin, high-electric-density, long-lasting proton exchange membrane for water electrolysis and its preparation method, which is basically the same as that in Example 1, except that: 899g of PFSA solution (solid content is 89.9g), 0.7g of gadolinium cerium oxide solid solution, 0.7g of cerium zirconium oxide solid solution, 0.7g of zirconium iridium oxide solid solution, 5g of PBI-H fiber, and 3g of crosslinking agent PBI-S (solid content).

[0191] The performance of an ultrathin, high-electric-density, long-durability proton exchange membrane for water electrolysis was tested and is as follows:

[0192] Film thickness 50.1µm, conductivity 0.202S / cm, HFR@80℃ 102mΩ·cm 2 The actual durability test was completed after 11466 hours of operation. The initial voltage was 1.706 V, with a voltage decay of 15 µV / h. The strength was 43.5 MPa. After durability testing, the hydrogen content in the oxygen (hydrogen permeation) was 0.39%, and the fluorine release from the FER was 0.6 µmol·m³. -2 ·h -1 . Example 4

[0193] This embodiment provides an ultrathin, high-electric-density, long-lasting proton exchange membrane for water electrolysis and its preparation method, which is basically the same as that in Example 1, except that: 850g of PFSA solution (85g of solid content), 1.0g of gadolinium cerium oxide solid solution, 1.0g of cerium zirconium oxide solid solution, 1.0g of zirconium iridium oxide solid solution, 7g of PBI-H fiber, and 5g of crosslinking agent PBI-S (solid content).

[0194] The performance of an ultrathin, high-electric-density, long-durability proton exchange membrane for water electrolysis was tested and is as follows:

[0195] Film thickness 49.9µm, conductivity 0.196S / cm, HFR@80℃ 115mΩ·cm 2 The system operated for 12024 hours before stopping. Initial voltage was 1.761 V, voltage decay was 14 µV / h, intensity was 45.0 MPa, and after durability testing, hydrogen permeation in oxygen was 0.38%, and fluorine release via FER was 0.8 µmol·m³. -2 ·h -1 . Example 5

[0196] This embodiment provides an ultrathin, high-electric-density, long-lasting proton exchange membrane for water electrolysis and its preparation method, which is basically the same as that in Example 1, except that: 976g of PFSA solution (solid content is 97.6g), 0.1g of gadolinium cerium oxide solid solution, 0.1g of cerium zirconium oxide solid solution, 0.1g of zirconium iridium oxide solid solution, 2g of PBI-H fiber, and 0.1g of crosslinking agent PBI-S (solid content).

[0197] The performance of an ultrathin, high-electric-density, long-durability proton exchange membrane for water electrolysis was tested and is as follows:

[0198] A 50.0 µm thick membrane with a conductivity of 0.238 S / cm and an HFR of 82 mΩ·cm at 80℃. 2 The actual durability test lasted 6556 hours, with an initial voltage of 1.670 V, a voltage decay of 25 µV / h, a strength of 36.0 MPa, and after durability testing, the hydrogen content in the oxygen (hydrogen permeation) was 1.2%, and the fluorine release from the FER was 1.5 µmol·m³. -2 ·h -1 . Comparative Example 1

[0199] This embodiment provides an electrolytic water proton exchange membrane and its preparation method, which is basically the same as that in Example 1, except that: 900g of PFSA solution (90g of solid content), does not contain a three-component composite solid solution system (Gd-Ce, Ce-Zr, Zr-Ir oxide solid solution), 5g of PBI-H fiber, and 5g of crosslinking agent PBI-S (solid content).

[0200] The performance of the proton exchange membrane for water electrolysis was tested and is as follows:

[0201] Film thickness 49.7µm, conductivity 0.195S / cm, HFR@80℃ 120mΩ·cm 2 Durability 3657 h, initial voltage 1.783 V, voltage decay 42 µV / h, strength 43.0 MPa, hydrogen permeation in oxygen after durability 0.6%, fluorine release 2.8 µmol·m³ / h. -2 ·h -1 . Comparative Example 2

[0202] This embodiment provides a water electrolysis proton exchange membrane and its preparation method, which is basically the same as that in Example 1, except that: 890g of PFSA solution (89g solid content), 1g of gadolinium cerium oxide solid solution coated with PBI-S, 5g of PBI-H fiber, and 5g of crosslinking agent PBI-S (solid content) are added. It does not contain cerium zirconium oxide solid solution or zirconium iridium oxide solid solution coated with PBI-S.

[0203] The performance of the proton exchange membrane for water electrolysis was tested and is as follows:

[0204] Film thickness 50.2µm, conductivity 0.198 S / cm, HFR@80℃ 110mΩ·cm 2Durability 4889h, initial voltage 1.750V, voltage decay 36 µV / h, strength 43.5MPa, hydrogen permeation in oxygen after durability is 0.55%, fluorine release from FER is 2.0 µmol·m -2 ·h -1 . Comparative Example 3

[0205] This embodiment provides a water electrolysis proton exchange membrane and its preparation method, which is basically the same as that in Example 1, except that: 890g of PFSA solution (89g solid content), 0.5g each of cerium-zirconium oxide solid solution and gadolinium-cerium oxide solid solution coated with PBI-S, 5g of PBI-H fiber, and 5g of crosslinking agent PBI-S (solid content). It does not contain zirconium-iridium oxide solid solution coated with PBI-S.

[0206] The performance of the proton exchange membrane for water electrolysis was tested and is as follows:

[0207] Film thickness 50.1µm, conductivity 0.201 S / cm, HFR@80℃ 102mΩ·cm 2 Durability 5822h, initial voltage 1.710V, voltage decay 32µV / h, strength 44.0MPa, hydrogen permeation in oxygen after durability test 0.50%, fluorine release 1.6µmol·m³. -2 ·h -1 . Comparative Example 4

[0208] This embodiment provides an electrolytic water proton exchange membrane and its preparation method, which is basically the same as that in Example 1, except that: 945g of PFSA solution (solid content is 94.5g), 0.5g of gadolinium cerium oxide solid solution, 0.5g of cerium zirconium oxide solid solution, 0.5g of zirconium iridium oxide solid solution, does not contain PBI-H fiber, and 4g of crosslinking agent PBI-S (solid content).

[0209] The performance of the proton exchange membrane for water electrolysis was tested and is as follows:

[0210] Film thickness 50.0µm, conductivity 0.207S / cm, HFR@80℃ 97mΩ·cm 2 Durability 5241h, initial voltage 1.695V, voltage decay 31µV / h, strength 29.0MPa, hydrogen permeation in oxygen after durability test 0.65%, fluorine release 1.7µmol·m³. -2 ·h -1 . Comparative Example 5

[0211] This embodiment provides an electrolytic water proton exchange membrane and its preparation method, which is basically the same as that in Example 1, except that: 945g of PFSA solution (solid content is 94.5g), 0.5g of gadolinium cerium oxide solid solution, 0.5g of cerium zirconium oxide solid solution, 0.5g of zirconium iridium oxide solid solution, 4g of PBI-H fiber, and no crosslinking agent PBI-S.

[0212] The performance of the proton exchange membrane for water electrolysis was tested and is as follows:

[0213] Film thickness 49.8µm, conductivity 0.208S / cm, HFR@80℃ 95mΩ·cm 2 Durability 4854h, initial voltage 1.693V, voltage decay 30µV / h, strength 40.0MPa, hydrogen permeation in oxygen after durability test 0.58%, fluorine release 1.9µmol·m³. -2 ·h -1 . Comparative Example 6

[0214] This embodiment provides an electrolytic water proton exchange membrane and its preparation method, which is basically the same as that in Example 1, except that: 940g of PFSA solution (94g of solid content), without the three-component composite solid solution system (Gd–Ce, Ce–Zr, Zr–Ir oxide solid solution), PBI-H fiber, and 6g of crosslinking agent PBI-S (solid content).

[0215] The performance of the proton exchange membrane for water electrolysis was tested and is as follows:

[0216] Film thickness 50.1µm, conductivity 0.204S / cm, HFR@80℃ 100mΩ·cm 2 Durability 2991 h, initial voltage 1.700 V, voltage decay 48 µV / h, strength 32.0 MPa, hydrogen permeation in oxygen after durability 0.75%. FER fluorine release 3.2 μmol·m -2 ·h -1 . Comparative Example 7

[0217] This embodiment provides an electrolytic water proton exchange membrane and its preparation method, which is basically the same as that in Example 1, except that: 930g of PFSA solution (solid content is 93g), and it does not contain the three-component composite solid solution system (Gd-Ce, Ce-Zr, Zr-Ir oxide solid solution) and 7g of crosslinking agent PBI-S, PBI-H fiber.

[0218] The performance of the proton exchange membrane for water electrolysis was tested and is as follows:

[0219] Film thickness 50.0µm, conductivity 0.200S / cm, HFR@80℃ 108mΩ·cm 2 Durability 3376 h, initial voltage 1.730 V, voltage decay 46 µV / h, strength 44.0 MPa, hydrogen permeation in oxygen 0.70%. FER fluorine release 3.0 μmol·m -2 ·h -1 . Comparative Example 8

[0220] This embodiment provides a proton exchange membrane for water electrolysis and its preparation method. The proton exchange membrane is prepared using pure resin (i.e., 100g of PFSA), and its performance is as follows:

[0221] Film thickness 50.5µm, conductivity 0.270S / cm, HFR@80℃ 62mΩ·cm 2 Durability 800h, initial voltage 1.570V, voltage decay 50µV / h, strength 25MPa, hydrogen permeation in oxygen after durability >8%, FER fluorine release 15µmol·m -2 ·h -1 . Comparative Example 9

[0222] This embodiment provides an ultrathin, high-electric-density, long-durability proton exchange membrane for water electrolysis and its preparation method, which is basically the same as that in Example 1, except that long-side-chain PFSA (Nafion D2020CS) is used instead of 3M 700EW.

[0223] The performance of the proton exchange membrane for water electrolysis was tested and is as follows:

[0224] Film thickness 49.9µm, conductivity 0.206S / cm, HFR@80℃ 98mΩ·cm 2 Durability 5558h, initial voltage 1.697V, voltage decay 38µV / h, strength 42.0MPa, hydrogen permeation in oxygen after durability test 0.60%, fluorine release 2.2µmol·m³ / h. -2 ·h -1 . Comparative Example 10

[0225] This embodiment provides a proton exchange membrane for water electrolysis and its preparation method, using commercial N212 (50µm standard membrane), and its performance is as follows:

[0226] Film thickness 50.0µm, conductivity 0.210S / cm, HFR@80℃ 95mΩ·cm 2Durability 2133h, initial voltage 1.692V, voltage decay 54.4µV / h, strength 23.0MPa, hydrogen permeation in oxygen after durability test 5.0%, fluorine release 3.0µmolm -2 ·h -1 . Comparative Example 11

[0227] This embodiment provides a proton exchange membrane for water electrolysis and its preparation method, using commercial N115 (125µm standard membrane), and its performance is as follows:

[0228] Film thickness 124.9µm, conductivity 0.174S / cm, HFR@80℃ 145mΩ·cm 2 Durability 11023h, initial voltage 1.90V, voltage decay 13µV / h, strength 29.0MPa, hydrogen permeation in oxygen after durability is 0.38%, fluorine release from FER is 1.0µmol·m -2 ·h -1 . Comparative Example 12

[0229] This embodiment provides an ultrathin, high-electric-density, long-lasting proton exchange membrane for water electrolysis and its preparation method, which is basically the same as that in Example 1, except that: 925g of PFSA solution (solid content is 92.5g), 0.5g of gadolinium cerium oxide solid solution, 0.5g of cerium zirconium oxide solid solution, 0.5g of MnO2 instead of zirconium iridium oxide solid solution, 4g of PBI-H fiber, and 2g of crosslinking agent PBI-S.

[0230] The performance of the proton exchange membrane for water electrolysis was tested and is as follows:

[0231] Film thickness 49.9µm, conductivity 0.194S / cm, HFR@80℃ 135mΩ·cm 2 Durability 5553h, initial voltage 1.800V, voltage decay 34µV / h, strength 40.0MPa, hydrogen permeation in oxygen after durability is 0.62%, and fluorine release via FER is 1.6µmol·m³. -2 ·h -1 .

[0232] The feed amounts and performance parameters for each embodiment and comparative example are shown in the table below:

[0233] Table 1

[0234]

[0235] Table 2

[0236]

[0237] This invention proposes an ultrathin composite proton exchange membrane composed of a PBI-H / PFSA composite framework membrane and a filling resin layer. The resin layer incorporates a three-component composite solid solution system (Gd–Ce, Ce–Zr, Zr–Ir oxide solid solutions) coated on the surface of PBI-S as a functional additive, and utilizes PBI-S to crosslink and modify the PFSA resin, constructing a stable ion / interface reinforcement network within the resin layer. This network forms an interpenetrating and confined coupling structure with the composite framework membrane, thereby achieving comprehensive performance characteristics such as high mechanical strength, excellent chemical stability, low gas cross-permeability, and long service life at a thickness of approximately 50 µm.

[0238] At the chemical protection level, the "three-component composite solid solution system + PBI-S coating and anchoring" constitutes a complete barrier covering peroxide decomposition and free radical scavenging. Comparative data show that the absence of any component (especially the zirconium-iridium solid solution that decomposes peroxides at the source) leads to a significant decrease in membrane lifetime and chemical stability (measured by the fluoride ion release rate, FER). The complete system of this invention (as in Example 1) can control the FER at an extremely low 0.8 µmol·m⁻¹. -2 ·h -1 The performance and lifetime are more than 5 times that of commercial ultrathin film N212, and significantly better than solutions using traditional MnO2 as an alternative material.

[0239] At the level of physical stability, the "high-strength composite framework membrane" and the "PBI-S crosslinking network" together provide a dual structural guarantee against mechanical and interfacial failures. Data shows that the absence of the PBI-H framework causes the membrane's tensile strength to plummet from over 40 MPa to 29 MPa (Comparative Example 4), highlighting the irreplaceable role of mechanical support; while the lack of PBI-S crosslinking weakens interfacial bonding, leading to decreased gas barrier properties and compromised durability (Comparative Example 5). The combination of these two elements ensures the ultrathin film's stability at high current densities (≥2 A·cm). -2 Dimensional stability and low gas permeability under operating conditions.

[0240] Furthermore, the compatibility of preferred short-side-chain perfluorosulfonic acid polymers (such as 3M 700EW) with the system of this invention has proven to be a crucial factor. The comparative film (Comparative Example 9) using long-side-chain Nafion, under the same structure, had a lifetime of only about 5558 hours, far lower than the performance of this invention, highlighting the importance of the overall design of the material system.

[0241] Examples 1-4 demonstrate that by optimizing the content of each component (such as solid solution and PBI-S), an optimal balance can be achieved between high proton conductivity (low surface resistivity, HFR), ultra-high mechanical strength (40-45 MPa), and ultra-long service life.

[0242] In summary, the ultrathin, high-electric-density, long-lasting proton exchange membrane for water electrolysis provided by this invention offers an effective solution to the key technical challenges of reducing membrane costs and improving system efficiency and durability in the field of PEM water electrolysis for hydrogen production.

[0243] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. An ultrathin, high-electric-density, long-lasting proton exchange membrane for water electrolysis, with a thickness of 45~55 µm, characterized in that: It includes a PBI-H / PFSA composite skeleton membrane and a PBI-S crosslinked modified short-side-chain perfluorosulfonic acid polymer resin layer formed on and filling the PBI-H / PFSA composite skeleton membrane, wherein the thickness of the PBI-H / PFSA composite skeleton membrane is 10~20µm; the mass ratio of the PBI-H / PFSA composite skeleton membrane to the PBI-S crosslinked modified short-side-chain perfluorosulfonic acid polymer resin layer is (2~7):(85~97.6). The PBI-H / PFSA composite framework membrane comprises the following raw material components in parts by weight: PBI-H 100~200 servings; 100 parts of short-side-chain perfluorosulfonic acid polymer resin; The PBI-S crosslinked modified short-side-chain perfluorosulfonic acid polymer resin layer comprises the following raw material components in parts by weight: 85-97.6 parts of short-side-chain perfluorosulfonic acid polymer resin; Crosslinking agent PBI-S: 0.1~5 parts; 0.1 to 1 part of gadolinium cerium oxide solid solution with PBI-S coating on the surface; 0.1 to 1 part of cerium zirconium oxide solid solution with PBI-S coating on the surface; 0.1 to 1 part of zirconium iridium oxide solid solution with PBI-S coating on the surface; The gadolinium cerium oxide solid solution, the cerium zirconium oxide solid solution, and the zirconium iridium oxide solid solution coated with PBI-S all have a particle size ≤150 nm.

2. The ultrathin, high-electric-density, long-lasting proton exchange membrane for water electrolysis as described in claim 1, characterized in that, Based on 85 to 97.6 parts by weight of the short-side-chain perfluorosulfonic acid polymer resin, the PBI-S used to form a PBI-S coating layer on any of the surfaces of the gadolinium cerium oxide solid solution, cerium zirconium oxide solid solution, or zirconium iridium oxide solid solution is independently 0.018 to 0.21 parts by weight.

3. The ultrathin, high-electric-density, long-lasting proton exchange membrane for water electrolysis as described in claim 2, characterized in that, The gadolinium cerium oxide solid solution, the cerium zirconium oxide solid solution, and the zirconium iridium oxide solid solution coated with PBI-S are prepared by independently combining the corresponding oxide solid solutions with the PBI-S coating solution and removing the solvent. Based on 100 parts by weight of the gadolinium cerium oxide solid solution, cerium zirconium oxide solid solution, or zirconium iridium oxide solid solution, the PBI-S coating solution comprises the following components: PBI-S 1~10 servings; DMAc 500~10000 copies; 0.05~0.1 parts of PVP or CTAB.

4. The ultrathin, high-electric-density, long-lasting proton exchange membrane for water electrolysis as described in claim 1, characterized in that, The Ew of the short-side-chain perfluorosulfonic acid polymer resin is 670~1000 g / mol.

5. The ultrathin, high-electric-density, long-lasting proton exchange membrane for water electrolysis as described in claim 1, characterized in that, The crosslinking agent PBI-S has a molecular weight of 1.6 × 10⁻⁶. 4 ~5×10 4 g / mol.

6. The ultrathin, high-electric-density, long-lasting proton exchange membrane for water electrolysis as described in claim 1, characterized in that, The PBI-S crosslinked modified short-side-chain perfluorosulfonic acid polymer resin layer is a continuous phase formed by curing the PBI-S crosslinked modified short-side-chain perfluorosulfonic acid polymer solution. The raw material of the PBI-S crosslinked modified short-side-chain perfluorosulfonic acid polymer solution includes the PBI-S crosslinked short-side-chain perfluorosulfonic acid polymer solution, which contains the following raw material components in parts by weight: 600-3000 parts of short-side-chain perfluorosulfonic acid polymer resin; 30 copies of PBI-S; NaOH 14.4~33.6 parts; Water 45.6~106.4 parts; 700-1000 parts of ethanol; DMA solution (50wt%) 30~100 parts; DMAc 31~152 copies; Isopropanol 425~23028 parts.

7. The method for preparing the ultrathin, high-electric-density, long-durability proton exchange membrane for water electrolysis according to any one of claims 1 to 6, characterized in that, Includes the following steps: (a) The gadolinium cerium oxide solid solution, cerium zirconium oxide solid solution and zirconium iridium oxide solid solution are added to an organic solvent containing PBI-S and dispersed to achieve coating, thereby obtaining their respective oxide solid solution dispersions. (b) The oxide solid solution dispersion is subjected to solvent removal to obtain a PBI-S coated oxide solid solution mixture; (c) The PBI-S coated oxide solid solution mixture is added to the PBI-S crosslinked short-side chain perfluorosulfonic acid polymer solution in proportion and dispersed to obtain a PBI-S crosslinked modified short-side chain perfluorosulfonic acid polymer casting coating film solution with coated solid solution dispersion. (d) The cast coating solution is used to coat and fill the PBI-H / PFSA composite skeleton membrane and dried to form a film; then the cast coating solution is used to coat the other side of the PBI-H / PFSA composite skeleton membrane and dried to form a film; post-treatment is performed to remove residual solvent, and finally annealing and crystallization are performed to obtain a proton exchange membrane with a thickness of 45~55 µm.

8. The method for preparing the ultrathin, high-electrical-density, long-lasting proton exchange membrane for water electrolysis according to claim 7, characterized in that: In step (b), the solvent removal is achieved by coating the solid solution dispersion onto the substrate and drying it. The coating method includes at least one of spin coating, blade coating, and spray coating. When spin coating is used, the solvent is first diffused at a low speed of 500-1000 rpm and then the excess solvent is spun off at 2000-4000 rpm. In step (d), the annealing crystallization temperature is 160-210°C and the annealing crystallization time is 10-60 min.

9. The application of the ultrathin, high-electric-density, long-durability proton exchange membrane for water electrolysis according to any one of claims 1 to 6 in the preparation of a proton exchange membrane water electrolysis hydrogen production device.

10. The application according to claim 9, characterized in that, The proton exchange membrane water electrolysis hydrogen production device can produce hydrogen at a rate of not less than 2 A / cm. 2 It operates stably under current density.

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