Seawater electrolysis system and manufacturing method therefor

Abstract

The present invention relates to a seawater electrolysis system and a manufacturing method therefor and, specifically, to a seawater electrolysis system comprising a hydrophobic porous separation membrane and an anion exchange membrane, and to a manufacturing method therefor. The present invention relates to a seawater electrolysis system comprising: a first hydrophobic porous separation membrane; an anion exchange membrane; a second hydrophobic porous separation membrane; and an electrolyte, and further comprising: a cathode between the first hydrophobic porous separation membrane and the anion exchange membrane; and an anode between the anion exchange membrane and the second hydrophobic porous separation membrane.

Description

Seawater electrolysis system and manufacturing method thereof

[0001] The present invention relates to a seawater electrolysis system and a method for manufacturing the same, and more particularly, to a seawater electrolysis system including a hydrophobic porous separation membrane and an anion exchange membrane and a method for manufacturing the same.

[0002] Seawater electrolysis is attracting attention as an environmentally friendly method of producing hydrogen by decomposing water into hydrogen and oxygen. In particular, the ability to utilize seawater, which is more abundant than freshwater, for electrolysis offers significant advantages in terms of cost-effectiveness and sustainability. For this reason, research and development of seawater-based electrolysis systems are actively underway across various industries.

[0003] Traditional seawater electrolysis systems typically use a hydrophilic diaphragm to separate the anode and cathode. While this diaphragm offers the advantages of structural simplicity and low manufacturing costs, it has the disadvantage of not effectively blocking the penetration of various impurity ions present in seawater.

[0004] These structural limitations frequently lead to problems such as scaling, electrode surface fouling, and reduced ion selectivity. Scaling, in particular, not only reduces electrode reaction efficiency but also serves as a major factor in shortening the life of the electrolysis device. Furthermore, the reduced selectivity due to ion interference lowers the energy efficiency of the entire system, resulting in high maintenance costs and complex operating procedures.

[0005] Therefore, for the practical application of seawater electrolysis, a new type of electrolysis membrane or isolation system with a selective blocking function for impurities and long-term stability and durability is required.

[0006] The technical problem to be achieved by the present invention is to provide a seawater electrolysis system including a hydrophobic porous separation membrane and an anion exchange membrane and a method for manufacturing the same.

[0007] However, the problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0008] One embodiment of the present invention provides a seawater electrolysis system comprising a first hydrophobic porous separation membrane; an anion exchange membrane; a second hydrophobic porous separation membrane; and an electrolyte; and a cathode between the first hydrophobic porous separation membrane and the anion exchange membrane; and an anode between the anion exchange membrane and the second hydrophobic porous separation membrane.

[0009] According to one embodiment of the present invention, the first hydrophobic porous separation membrane and the second hydrophobic porous separation membrane may include polytetrafluoroethylene (PTFE).

[0010] According to one embodiment of the present invention, the anion exchange membrane may include a silsesquioxane compound.

[0011] According to one embodiment of the present invention, the anion exchange membrane may include a silsesquioxane compound having a quaternary ammonium group introduced therein.

[0012] According to one embodiment of the present invention, the anion exchange membrane may contain a silsesquioxane compound in an amount of 5 wt% or more and 20 wt% or less based on 100 wt% of the total.

[0013] According to one embodiment of the present invention, the cathode and anode may include nickel foam and a catalyst layer.

[0014] According to one embodiment of the present invention, the cathode may include a catalyst including a metal such as Pt, Ru, Ni, Co, Fe or Mn.

[0015] According to one embodiment of the present invention, the electrolyte may include seawater.

[0016] One embodiment of the present invention provides a method for manufacturing a seawater electrolysis system, comprising the steps of: manufacturing an anion exchange membrane including a silsesquioxane compound; and introducing a quaternary ammonium group into the anion exchange membrane.

[0017] According to one embodiment of the present invention, the anion exchange membrane may contain a silsesquioxane compound in an amount of 5 wt% or more and 20 wt% or less based on 100 wt% of the total.

[0018] A seawater electrolysis system according to one embodiment of the present invention includes a hydrophobic porous separation membrane and an anion exchange membrane, thereby increasing the purity of water, improving the quality of hydrogen produced, and reducing the risk of catalyst decomposition due to impurities.

[0019] A seawater electrolysis system according to one embodiment of the present invention can have low electrical resistance and excellent durability under salt conditions by including a hydrophobic porous separation membrane and an anion exchange membrane.

[0020] Figure 1 is a schematic diagram of a seawater electrolysis system showing the arrangement of a hydrophobic porous separation membrane and an anion exchange membrane according to one embodiment of the present invention.

[0021] Figure 2 is a schematic diagram showing the selective permeability of a hydrophobic porous separation membrane according to one embodiment of the present invention.

[0022] Figure 3 illustrates a seawater electrolysis system with improved operational efficiency according to one embodiment of the present invention.

[0023] (A) of FIG. 4 shows a QA-POSS synthesis method according to one embodiment of the present invention, (B) is a schematic diagram of AEM production, (C) is a graph showing the ion exchange capacity (IEC) and water absorption (Wup) of QA-POSS at each concentration, and (D) is a QA-POSS EIS graph at each concentration.

[0024] (A) of FIG. 5 shows SEM images of QA-POSS at each concentration according to an embodiment of the present invention ((i) 5 wt%, (ii) 10 wt%, (iii) 15 wt%, and (iv) 20 wt%), (B) is an XRD analysis graph of a bare film and 15 wt% QA-POSS, (C) is a UTM analysis graph of a bare film and 15 wt% QA-POSS, and (D) is a TGA graph of a bare film and 15 wt% QA-POSS.

[0025] FIG. 6 (A) illustrates an HSWE (Hybrid sea water electrolyser) system according to one embodiment of the present invention, (B) is an LSV graph of an HSWE device, (C) is a graph comparing stability performance according to the presence or absence of seawater, and (D) illustrates the performance of an HSWE device including wind turbine integration.

[0026] In this specification, when a part is said to "include" a certain component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0027] In this specification, “A and / or B” means “A and B, or A or B.”

[0028] In this specification, “about,” “approximately,” and “substantially” are used to mean a range of or approximation to a numerical value or degree, taking into account inherent manufacturing and material tolerances, and are used to prevent infringers from unfairly using the disclosure, which mentions exact or absolute numbers provided to aid understanding of the present invention.

[0029] In this specification, when it is said that a component is “on”, this does not exclude other components being placed therebetween, unless otherwise specifically stated, but rather means that other components may be placed thereon.

[0030] Hereinafter, an embodiment of the present invention will be described in detail with reference to the attached drawings. The drawings may be exaggerated, omitted, or schematically illustrated to explain or emphasize the contents of an embodiment of the present invention.

[0031] Hereinafter, the present invention will be described in more detail.

[0032] One embodiment of the present invention provides a seawater electrolysis system comprising a first hydrophobic porous separation membrane; an anion exchange membrane; a second hydrophobic porous separation membrane; and an electrolyte; and a cathode between the first hydrophobic porous separation membrane and the anion exchange membrane; and an anode between the anion exchange membrane and the second hydrophobic porous separation membrane.

[0033] A seawater electrolysis system according to one embodiment of the present invention includes a hydrophobic porous separation membrane and an anion exchange membrane, thereby increasing the purity of water, improving the quality of hydrogen produced, and reducing the risk of catalyst decomposition due to impurities.

[0034] A seawater electrolysis system according to one embodiment of the present invention can have low electrical resistance and excellent durability under salt conditions by including a hydrophobic porous separation membrane and an anion exchange membrane.

[0035] Conventional diaphragms typically lack the ability to selectively allow the passage of desired molecules or ions while effectively blocking others. This lack of selectivity increases the risk of electrolyte contamination, necessitating frequent replacement and intensive purification processes. Furthermore, these diaphragms lack thermal and chemical stability in harsh saline environments, often resulting in material degradation over time.

[0036] Figure 1 is a schematic diagram of a seawater electrolysis system showing the arrangement of a hydrophobic porous separation membrane and an anion exchange membrane according to one embodiment of the present invention.

[0037] According to one embodiment of the present invention, the seawater electrolysis system includes a first hydrophobic porous separation membrane; an anion exchange membrane; a second hydrophobic porous separation membrane; and an electrolyte. As described above, the seawater electrolysis system includes the first hydrophobic porous separation membrane; anion exchange membrane; a second hydrophobic porous separation membrane; and an electrolyte, thereby maximizing the efficiency of the seawater electrolysis process.

[0038] According to one embodiment of the present invention, the anion exchange membrane (AEM) has high selectivity for specific ions, thereby allowing only desired ions to participate in the reaction, thereby improving the efficiency of electrolysis.

[0039] Additionally, the anion exchange membrane (AEM) has superior resistance to chemical degradation in salty environments compared to conventional diaphragms, which can result in a longer operating life and reduced maintenance.

[0040] In addition, the anion exchange membrane (AEM) can contribute to lowering energy consumption and increasing the hydrogen production rate by reducing the electrical resistance of the entire membrane.

[0041] Additionally, the anion exchange membrane (AEM) helps produce cleaner, purer hydrogen, which is important for environmental sustainability and can help meet global renewable energy goals.

[0042] According to one embodiment of the present invention, the first hydrophobic porous separation membrane and the second hydrophobic porous separation membrane may be the same, or may be distinguished for reasons of arrangement.

[0043] Figure 2 is a schematic diagram showing the selective permeability of a hydrophobic porous separation membrane according to one embodiment of the present invention.

[0044] According to one embodiment of the present invention, the hydrophobic porous membrane can enable selective water vapor transmission. Specifically, the hydrophobic porous membrane utilizes its hydrophobic and porous properties to selectively allow water vapor to pass through while simultaneously blocking the penetration of liquid seawater, salt, and impurity ions such as organic matter. This selective diffusion can reduce electrolyte contamination and prevent common problems such as scaling and fouling.

[0045] In addition, the hydrophobic porous separation membrane operates according to the membrane distillation principle in which water is distilled by heat and vapor pressure difference, so that only pure water vapor is condensed and can be used in the electrolysis process.

[0046] According to one embodiment of the present invention, the first hydrophobic porous separation membrane and the second hydrophobic porous separation membrane may contain polytetrafluoroethylene (PTFE). As described above, the first hydrophobic porous separation membrane and the second hydrophobic porous separation membrane contain polytetrafluoroethylene (PTFE), thereby selectively allowing water vapor to pass through while blocking the penetration of liquid seawater, salt, and impurity ions such as organic matter.

[0047] Additionally, the polytetrafluoroethylene (PTFE) membrane possesses a micrometer-scale porous structure that is inherently hydrophobic, allowing only water vapor to pass through while repelling liquid water and dissolved salts. This characteristic can prevent seawater impurities from entering the electrolysis chamber.

[0048] Furthermore, PTFE membranes utilize the membrane distillation principle, where water evaporates from the seawater side of the membrane and then diffuses as vapor through the pores along the vapor pressure gradient. These systems can optimally maintain this gradient, ensuring consistent performance.

[0049] According to one embodiment of the present invention, the anion exchange membrane (AEM) is strategically positioned adjacent to the PTFE membrane to promote efficient ion transport, particularly focusing on the transport of hydroxide ions required for the electrolysis reaction. The selective permeability of the AEM ensures that only the necessary ions participate in the reaction, thereby enhancing the purity and efficiency of hydrogen production.

[0050] Additionally, the AEM can provide high ionic conductivity and low electrical resistance, which are important for minimizing energy loss during electrolysis and improving the overall energy efficiency of the system.

[0051] According to one embodiment of the present invention, the hydrophobic porous separation membrane and the anion exchange membrane are assembled in a laminated configuration with minimal gaps to ensure efficient transfer of water vapor and ions between the two membranes. This tight lamination minimizes the diffusion path of water vapor, thereby contributing to improved water transfer speed and efficiency.

[0052] Furthermore, as water vapor passes through the PTFE membrane, it encounters the cooler surface of the AEM on the opposite side and condenses back into liquid water. This purified water can be immediately used in the electrolysis process, providing a continuous supply of high-purity water.

[0053] These systems include sensors and controls that monitor and regulate vapor pressure across the PTFE membrane and ion flow through the AEM. This control can be critical to maintaining system efficiency and operational stability under a variety of environmental conditions.

[0054] Furthermore, these systems are ideal for integration into renewable energy solutions in areas where seawater is abundant, such as coastal areas, and could significantly contribute to the sustainability of hydrogen as a clean energy carrier.

[0055] According to one embodiment of the present invention, the anion exchange membrane may include a silsesquioxane-based compound. As described above, by including the silsesquioxane-based compound, the anion exchange membrane has high selectivity for specific ions, thereby allowing only desired ions to participate in the reaction, thereby improving the efficiency of electrolysis.

[0056] According to one embodiment of the present invention, the anion exchange membrane comprises a quaternary ammonium group (-NR4 + ) may include a silsesquioxane compound introduced. As described above, the anion exchange membrane may include a quaternary ammonium group (-NR4 + ) can be introduced to improve the ion exchange capacity and enhance the efficiency of electrolysis by allowing only desired ions to participate in the reaction.

[0057] According to one embodiment of the present invention, the silsesquioxane-based compound may be included in an amount of 5 wt% to 20 wt% based on 100 wt% of the total anion exchange membrane. Specifically, the silsesquioxane-based compound may be included in an amount of 5 wt% to 20 wt%, 7 wt% to 18 wt%, 8 wt% to 16 wt%, 10 wt% to 16 wt%, 10 wt% to 15 wt%, or 12 wt% to 15 wt% based on 100 wt% of the total anion exchange membrane. By controlling the concentration of the silsesquioxane-based compound within the above-described range, resistance can be reduced, conductivity can be improved, and the efficiency of electrolysis can be improved.

[0058] According to one embodiment of the present invention, a cathode is included between the first hydrophobic porous separation membrane and the anion exchange membrane.

[0059] According to one embodiment of the present invention, an anode is included between the anion exchange membrane and the second hydrophobic porous separation membrane.

[0060] According to one embodiment of the present invention, the cathode and anode may include nickel foam and a catalyst layer. Specifically, the nickel foam may serve as a support for the cathode and anode. Nickel foam is a porous metal support with a large surface area and excellent electrical conductivity, making it suitable as an electrode.

[0061] According to one embodiment of the present invention, the cathode may include a catalyst including a metal such as Pt, Ru, Ni, Co, Fe or Mn.

[0062] According to one embodiment of the present invention, the electrolyte may include seawater. Specifically, by using seawater, an abundant resource, instead of purified or fresh water, a simple and economical seawater electrolysis process can be performed.

[0063] One embodiment of the present invention provides a method for manufacturing a seawater electrolysis system, comprising the steps of: manufacturing an anion exchange membrane including a silsesquioxane compound; and introducing a quaternary ammonium group into the anion exchange membrane.

[0064] According to one embodiment of the present invention, the silsesquioxane-based compound may be included in an amount of 5 wt% to 20 wt% based on 100 wt% of the total anion exchange membrane. Specifically, the silsesquioxane-based compound may be included in an amount of 5 wt% to 20 wt%, 7 wt% to 18 wt%, 8 wt% to 16 wt%, 10 wt% to 16 wt%, 10 wt% to 15 wt%, or 12 wt% to 15 wt% based on 100 wt% of the total anion exchange membrane. By controlling the concentration of the silsesquioxane-based compound within the above-described range, resistance can be reduced, conductivity can be improved, and the efficiency of electrolysis can be improved.

[0065] Hereinafter, the present invention will be described in detail using examples. However, the examples according to the present invention may be modified in various ways, and the scope of the present invention is not limited to the examples described below. The examples in this specification are provided to more fully explain the present invention to those of ordinary skill in the art.

[0066]

[0067] <Manufacturing Example>

[0068] Synthesis of octakis(3-chloropropyl)silsesquioxane (Cl-POSS)

[0069] A mixture of 300 ml of dry methanol and 10 ml of concentrated HCl was added to a two-necked round-bottom flask equipped with an additional funnel and stirred at 0 °C for 30 minutes.

[0070] Afterwards, 3-chloropropyl trimethoxysilane (30 g, 0.15 mol) was added dropwise through an addition funnel over 30 minutes and stirred for 2 hours. The reaction mixture was left at room temperature for 48 hours without stirring to ensure complete hydrolysis of the methoxy group (-OCH₃). Afterwards, di-n-butyltin dilaurate (0.3 g, 0.48 mmol) as a catalyst was added for self-condensation of the silane. The reaction mixture was stirred at room temperature for an additional 48 hours.

[0071] A white precipitate was formed, which was separated by filtration, washed three times with methanol to remove impurities, and finally dried in a vacuum to obtain Cl-POSS.

[0072]

[0073] Synthesis of octakis(3-iodopropyl)silsesquioxane (I-POSS)

[0074] The Cl-POSS (5 g) and sodium iodide (NaI, 10 g) prepared above were dissolved in dry THF (100 ml). The reaction mixture was stirred in a dark room at 60 °C for 72 hours to ensure complete replacement of Cl atoms with I atoms.

[0075] After evaporating THF, the initial product was extracted with CHCl3 and H2O.

[0076] The CHCl3 layer was passed through sodium sulfate (Na₂SO₄) to remove moisture content, and then passed through sodium thiosulfate (Na₂S₂O₃) to remove unreacted iodide.

[0077] Finally, after evaporation of the solvent, I-POSS was obtained in the form of a grayish-white solid.

[0078]

[0079] Synthesis of octakistriethylpropyl ammonium POSS (QA-POSS)

[0080] The above-mentioned I-POSS (4 g) was dissolved in a two-necked round-bottom flask containing 50 ml of DMF under N2.

[0081] Afterwards, triethylamine (TEA, 20 ml) was added dropwise using an addition funnel, and the reaction mixture was heated to 60 °C.

[0082] After 24 hours, the reaction mixture was vacuum-dried to evaporate the solvent and excess triethylamine, obtaining QA-POSS in the form of a brownish-yellow, sticky solid.

[0083] The above manufacturing process is shown in Fig. 4 (A).

[0084]

[0085] <Example>

[0086] Synthesis of anion exchange membrane (AEM)

[0087] AEMs containing 5, 10, 15, and 20 wt% of the above-mentioned QA-POSS (in order, Examples 1 to 4) were prepared as follows.

[0088] Bromide (br) - ) The exchangeable quaternary ammonium functionalized polysulfone Fumasep ionomer was dissolved in DMF, and the amount of QA-POSS required for complete mixing of the QA-POSS and Fumasep ionomer was added and stirred for 48 hours.

[0089] The homogeneous solution was placed in a clean, dry petri dish and dried under vacuum at 60°C to allow the solvent to evaporate slowly, obtaining AEM. The solution was then washed several times with water to remove any residual solvent.

[0090] Afterwards, the above AEM is hydrated (OH - ) was immersed in a 1M KOH solution for 24 hours to convert it into a form. The above synthesis process is shown in (B) of Fig. 4.

[0091]

[0092] Membrane Electrode Assembly (MEA) Manufacturing

[0093] A basic membrane electrode assembly (MEA) was fabricated using a high-concentration potassium hydroxide (KOH) solution as a self-dampening electrolyte (SDE), consisting of a platinum (Pt) cathode, an iridium dioxide (IrO₂) anode, a hydrophobic porous PTFE membrane, and 15% QA-POSS AEM (Example 3).

[0094]

[0095] <Experimental Example>

[0096] Conductivity (σ), ion exchange capacity (IEC), water absorption (Wup), and resistance measurements

[0097] (C) of FIG. 4 is a graph showing the QA-POSS ion exchange capacity (IEC) and water absorption (Wup) for each concentration of Examples 1 to 4, and (D) is a QA-POSS EIS graph for each concentration of Examples 1 to 4.

[0098] Specifically, ion exchange capacity (IEC) is a measure of the ability of an insoluble substance to exchange ions. As shown in FIG. 4C, the anion exchange membrane (AEM) according to one embodiment of the present invention exhibited IEC values ​​of 2.05, 2.15, 2.5, and 2.58 meq / g for 5%, 10%, 15%, and 20% QA-POSS, respectively. That is, the IEC value appeared to increase as the QA-POSS concentration increased. This may be because every single QA-POSS molecule contains eight quaternary ammonium ion-exchange groups. Additionally, hydrophilic properties may also contribute to the observed high IEC values. Although excessive moisture absorption can negatively affect the mechanical stability of AEMs, moisture absorption is considered an essential property of AEMs because both the effective charge density and electrical resistance of AEMs vary with moisture content.

[0099] According to Fig. 4 (C), it can be seen that the moisture absorption increases (up to 25%) for AEM containing 5 to 20% QA-POSS.

[0100] In addition, the conductivity of the ion exchange membrane (IEM) can vary depending on the IEC and the local water fraction (Wup) inside the membrane. According to Fig. 4(D), the resistance of the membrane tended to decrease in proportion to the QA-POSS concentration (the value of the graph x-axis moved to the left as the concentration increased). This can be attributed to the high density of ion exchange groups and the high surface area of ​​the nanofiller, which can be attributed to the OH through the AEM containing QA-POSS. - It can increase the conductivity of hydroxide by reducing the resistance to movement.

[0101]

[0102] Morphological analysis

[0103] Figure 5 (A) shows QA-POSS SEM images of each concentration according to one embodiment of the present invention ((i) 5 wt%, (ii) 10 wt%, (iii) 15 wt%, and (iv) 20 wt%).

[0104] The clean membrane exhibits a very smooth surface without any defects. The dispersion of QA-POSS within the polymer matrix can play a significant role in influencing the physical properties of the membrane.

[0105] According to Fig. 5 (A), the AEMs containing these QA-POSS were all shown from the SEM image to be almost smooth and exhibit a dense surface except for a very small number of particles.

[0106] According to (iii) of (A) of Fig. 5, the surface of AEM was slightly deformed when adding up to 15% QA-POSS filler, and the particles were uniformly embedded due to the excellent compatibility of POSS and the polymer matrix, and no phase separation was observed.

[0107] However, according to (iv) of (A) of Fig. 5, some POSS molecules were observed in 20% QA-POSS AEM, and there were no cracks or voids between the polymer and POSS aggregates.

[0108]

[0109] XRD analysis

[0110] To confirm the effect of QA-POSS on the crystalline property of the film, XRD analysis was performed, and Fig. 5 (B) shows the XRD analysis graph of the bare film and 15 wt% QA-POSS.

[0111] The bare film exhibited a broad peak at 2θ = 19-20°, indicating that the film had amorphous characteristics.

[0112] This can be seen as a result of the fact that the peak intensity of the polymer backbone decreased rapidly as QA-POSS was added, which resulted in a decrease in the polymer content within the membrane.

[0113] In general, as the amorphousness of a material increases, the ionic conductivity improves, so it can be seen that increasing amorphous properties is advantageous for ionic conduction.

[0114] As the QA-POSS content increased up to 15%, the peak intensity decreased in a similar trend, and a corresponding increase in conductivity was observed.

[0115] In contrast, when the QA-POSS content was 20%, the peak intensity increased slightly compared to the 15% membrane. In addition, an additional small peak appeared around 2θ = 8.5° in the 20% QA-POSS composite membrane, suggesting that POSS molecules were separately aggregated within the membrane.

[0116] From the XRD results, it can be concluded that Quaternized polysulfone (QPSU) can accommodate up to 15% QA-POSS filler without negatively affecting the membrane properties.

[0117]

[0118] Mechanical properties

[0119] Figure 5 (C) shows a UTM analysis graph of a bare film and 15 wt% QA-POSS.

[0120] The stress-strain curve of QPSU (Quaternized poly sulfone) was measured in a fully hydrated state.

[0121] According to Fig. 5(C), the tensile strength of the 15 wt% QA-POSS membrane is superior to that of the bare membrane. This result may be due to the superior dispersion of POSS compared to conventional inorganic fillers. Due to its weak binding affinity with POSS molecules and its compatibility with organic substituents, POSS can diffuse into the polymer matrix at the molecular level, reinforcing the matrix. The better dispersion (nanoscale distribution) of QA-POSS observed in the 15 wt% membrane resulted in a maximum tensile strength of approximately 38 MPa.

[0122]

[0123] TGA analysis

[0124] Figure 5 (D) shows a TGA graph of a bare film and 15 wt% QA-POSS.

[0125] According to Fig. 5(D), the 15 wt% QA-POSS film retains its mass up to a higher temperature than the bare film, demonstrating higher thermal stability. Therefore, it can be seen that it has excellent durability at high temperatures.

[0126]

[0127] Seawater electrolysis system performance evaluation

[0128] The performance of a seawater AEM electrolyzer was evaluated using the above-manufactured membrane electrode assembly (MEA).

[0129] FIG. 6 (A) illustrates an HSWE (Hybrid sea water electrolyser) system according to one embodiment of the present invention, (B) is an LSV graph of an HSWE device, (C) is a graph comparing stability performance according to the presence or absence of seawater, and (D) illustrates the performance of an HSWE device including wind turbine integration.

[0130] Specifically, according to (B) of Fig. 6, under seawater supply conditions, the MEA exhibited a current density of 800 mA / cm² at 2 V, which is a two-fold improvement in performance compared to the prior art. The main reason for this performance improvement can be attributed to the use of an AEM membrane instead of a hydrophilic diaphragm.

[0131] To validate the seawater electrolysis concept, a laboratory-scale seawater electrolysis system (SES) with a symmetrical structure was first constructed for electrochemical performance studies. The electrode catalyst layer was fixed to the electrode plates, and a 15% QA-POSS membrane was used to separate the two electrodes and prevent mixing of hydrogen (H2) and oxygen (O2). The SDE storage frame provides the SDE environment and holds a hydrophobic porous PTFE membrane through which water movement occurs. Furthermore, the PTFE membrane completely separates the SDE from the seawater. The hydrophobic porous PTFE membrane introduces tightly connected micrometer-scale gas diffusion pathways between the seawater and SDE, enabling directional water vapor transport while completely preventing liquid infiltration. Mass transfer through these gas diffusion pathways occurs via the liquid-gas-liquid phase transition. Liquid water evaporates to form a gas phase on the seawater side and then migrates through the membrane in a gas-water phase. Subsequently, it is absorbed by the SDE and liquefied again. The multi-fluorine structure of PTFE has a low surface energy, forming superhydrophobic isolation domains that can inhibit the penetration of seawater and ions over time. The HSWE operated steadily for over 15,000 minutes to produce H2 from seawater at an average voltage of approximately 1.8 V (Figure 6 (C)). Due to the continuous consumption of seawater over a long period during the electrolysis process, the seawater level inside the container gradually dropped, indicating that water molecules in the seawater migrated toward the SDE.

[0132] These results may support sustainable H2 production based on liquid-gas.

[0133] Furthermore, the seawater electrolyzer was integrated with windmills and solar power generation, and the H2 and O2 production was measured and displayed on a radar chart (Fig. 6 (D)).

[0134] Therefore, the seawater electrolysis system and its manufacturing method according to one embodiment of the present invention can improve the efficiency and purity of hydrogen production through effective ion separation and selective diffusion mechanism of water vapor by including a hydrophobic porous separation membrane and an anion exchange membrane.

[0135]

[0136] [Explanation of symbols]

[0137] 1: Cathode

[0138] 2: Seawater

[0139] 3: Hydrophobic porous membrane

[0140] 4: Anion exchange membrane

[0141] 5: Permeated water vapor and alkali salts

[0142] 6: Anode

[0143] The present invention can improve the quality of hydrogen produced by increasing the purity of water by including a hydrophobic porous separation membrane and an anion exchange membrane, and reduce the risk of catalyst decomposition due to impurities.

Claims

1. A first hydrophobic porous separation membrane; an anion exchange membrane; a second hydrophobic porous separation membrane; and an electrolyte; A cathode is included between the first hydrophobic porous separation membrane and the anion exchange membrane; A seawater electrolysis system comprising an anode between the anion exchange membrane and the second hydrophobic porous separation membrane.

2. In claim 1, A seawater electrolysis system, wherein the first hydrophobic porous separation membrane and the second hydrophobic porous separation membrane comprise polytetrafluoroethylene (PTFE).

3. In claim 1, A seawater electrolysis system, wherein the anion exchange membrane comprises a silsesquioxane compound.

4. In claim 3, A seawater electrolysis system, wherein the above anion exchange membrane comprises a silsesquioxane compound having a quaternary ammonium group introduced therein.

5. In claim 3, A seawater electrolysis system comprising a silsesquioxane compound in an amount of 5 wt% or more and 20 wt% or less based on 100 wt% of the total anion exchange membrane.

6. In claim 1, A seawater electrolysis system, wherein the cathode and anode include nickel foam and a catalyst layer.

7. In claim 6, A seawater electrolysis system, wherein the cathode comprises a catalyst including a metal such as Pt, Ru, Ni, Co, Fe or Mn.

8. In claim 1, A seawater electrolysis system, wherein the electrolyte contains seawater.

9. A method for manufacturing a seawater electrolysis system according to any one of claims 1 to 8, A step of manufacturing an anion exchange membrane comprising a silsesquioxane compound; and A method for manufacturing a seawater electrolysis system, comprising: a step of introducing a quaternary ammonium group into the anion exchange membrane.

10. In claim 9, A method for manufacturing a seawater electrolysis system, comprising a silsesquioxane compound in an amount of 5 wt% or more and 20 wt% or less based on 100 wt% of the total anion exchange membrane.

Images