Reverse electrodialysis based water electrolyser

Abstract

The present invention relates to a reverse electrodialysis-based water electrolysis device capable of producing hydrogen and oxygen with low electricity consumption and generating electricity in an environmentally friendly manner by introducing an exchange membrane with an electrode layer bonded to its surface. The reverse electrodialysis-based water electrolysis device of the present invention can ensure economic viability by producing hydrogen and oxygen with low electricity consumption, and can reduce environmental pollution by generating electricity in an eco-friendly manner. In addition, economic viability can be ensured by utilizing seawater to produce hydrogen.

Description

Technology Field

[0001] The present invention relates to a reverse electrodialysis-based water electrolysis device capable of producing hydrogen and oxygen with low electricity consumption and generating electricity in an environmentally friendly manner by introducing an exchange membrane with an electrode layer bonded to its surface. Background Technology

[0003] As the use of fossil fuels has increased rapidly alongside technological advancements, problems such as accelerated global warming and environmental destruction have arisen, leading to the emergence of a need for eco-friendly energy to replace them. Hydrogen, which is attracting attention as a representative eco-friendly energy source, does not generate pollutants during combustion, and is therefore considered a future growth engine as a pollution-free, eco-friendly energy source to replace coal and oil.

[0004] Water electrolysis (WE) is an electrochemical technology that generates hydrogen and oxygen by electrolyzing water and moving ions through a membrane. It is typically classified into alkaline water electrolysis, cation exchange membrane water electrolysis, and anion exchange membrane water electrolysis. Although hydrogen can be produced using these water electrolysis technologies, conventional water electrolysis technologies have the disadvantage of high production costs and low energy efficiency due to the significant amount of electricity consumed during the water electrolysis process. Therefore, there is an urgent need for research to produce hydrogen more efficiently by reducing the amount of electricity consumed during the water electrolysis process.

[0005] Meanwhile, reverse-electrodialysis (RED) is a system that generates power by recovering energy from the difference in salinity or concentration generated during the mixing of two fluids with different concentrations, such as seawater and freshwater, in the form of electrical energy. It is a power generation method that directly converts chemical energy generated as ions dissolved in seawater (saltwater) move through an ion exchange membrane into electrical energy.

[0006] Against this backdrop, the inventors, through research efforts to develop a device for generating electrical energy in an environmentally friendly manner while reducing electricity consumption during the hydrogen production process using water electrolysis, completed the present invention by manufacturing a water electrolysis device based on reverse electrodialysis. Prior art literature

[0008] Korean Published Patent No. 10-2023-0117947 The problem to be solved

[0009] The present invention aims to solve the aforementioned problem and other related problems.

[0010] One exemplary objective of the present invention is to manufacture a water electrolysis device based on reverse electrodialysis and to provide a device that generates electrical energy by reverse electrodialysis and simultaneously produces hydrogen and oxygen with a reduced amount of electricity using the generated electrical energy.

[0011] The technical problems to be solved according to the technical concept of the invention disclosed in this specification are not limited to those for solving the problems mentioned above, and other unmentioned problems will be clearly understood by a person skilled in the art from the description below. means of solving the problem

[0013] As an embodiment for achieving the above objective, one example of the present invention is

[0014] A cathode electrode and an anode electrode facing each other;

[0015] An ion exchange membrane stack arranged between the cathode electrode and the anode electrode, wherein an anion exchange membrane and a cation exchange membrane are alternately arranged so as to be partitioned into a plurality of first flow paths through which a first solution flows and second flow paths through which a second solution containing a salt with a higher concentration than the first solution flows; and

[0016] A water electrolysis device is provided, comprising an electrode layer bonded to the surface of the anion exchange membrane or cation exchange membrane.

[0017] As another embodiment for achieving the above objective, one example of the present invention is

[0018] A cathode electrode and an anode electrode facing each other;

[0019] An ion exchange membrane stack arranged between the cathode electrode and the anode electrode; wherein an anion exchange membrane, a cation exchange membrane, and an osmotic membrane are alternately arranged so as to be divided into a plurality of sections, each section being divided into a first flow path through which a first solution flows, a second flow path through which a second solution containing a higher concentration of salt than the first solution flows, and a third flow path through which seawater flows;

[0020] A water electrolysis device is provided, comprising an electrode layer bonded to the surface of the anion exchange membrane or the cation exchange membrane. Effects of the invention

[0022] The reverse electrodialysis-based water electrolysis device of the present invention can ensure economic viability by producing hydrogen and oxygen with low electricity consumption, and can reduce environmental pollution by generating electricity in an eco-friendly manner. In addition, economic viability can be ensured by utilizing seawater to produce hydrogen.

[0023] Meanwhile, the scope of the present invention is not limited by the effects described above. Brief explanation of the drawing

[0025] FIG. 1 is a cross-sectional view of a water electrolysis device according to one embodiment of the present invention. FIG. 2 is a diagram showing the combined state of the water electrolysis device illustrated in FIG. 1 (left) and the state in which an anion exchange membrane, a cation exchange membrane, and a closed gasket are stacked in multiple stages (right). FIG. 3 is a diagram showing the combined state of the water electrolysis device illustrated in FIG. 1 (left) and the state in which an anion exchange membrane, a cation exchange membrane, and an open gasket are stacked in multiple stages (right). FIG. 4 is a cross-sectional view of a water electrolysis device according to another embodiment of the present invention. FIG. 5 is a diagram showing the combined state of the water electrolysis device illustrated in FIG. 4 (left) and the state in which an anion exchange membrane, a cation exchange membrane, and a closed gasket are stacked in multiple stages (right). FIG. 6 is a diagram showing the combined state of the water electrolysis device illustrated in FIG. 4 (left) and the state in which an anion exchange membrane, a cation exchange membrane, and an open gasket are stacked in multiple stages (right). FIG. 7 is a cross-sectional view of a water electrolysis device according to another embodiment of the present invention. FIG. 8 is a diagram showing the combined state of the water electrolysis device illustrated in FIG. 7 (left) and the state in which an anion exchange membrane, a cation exchange membrane, an osmotic membrane, and a closed gasket are stacked in multiple stages (right). FIG. 9 is a diagram showing the combined state of the water electrolysis device illustrated in FIG. 7 (left) and the state in which an anion exchange membrane, a cation exchange membrane, an osmotic membrane, and an open gasket are stacked in multiple stages (right). FIG. 10 is a cross-sectional view of a water electrolysis device according to another embodiment of the present invention. FIG. 11 is a diagram showing the combined state of the water electrolysis device illustrated in FIG. 10 (left) and the state in which an anion exchange membrane, a cation exchange membrane, an osmotic membrane, and a closed gasket are stacked in multiple stages (right). FIG. 12 is a diagram showing the combined state of the water electrolysis device illustrated in FIG. 10 (left) and the state in which an anion exchange membrane, a cation exchange membrane, an osmotic membrane, and an open gasket are stacked in multiple stages (right). FIG. 13 is a cross-sectional view of a water electrolysis device according to another embodiment of the present invention. FIG. 14 is a diagram showing the combined state of the water electrolysis device illustrated in FIG. 13 (left) and the state in which an anion exchange membrane, a cation exchange membrane, an osmotic membrane, and a closed gasket are stacked in multiple stages (right). FIG. 15 is a diagram showing the combined state of the water electrolysis device illustrated in FIG. 13 (left) and the state in which an anion exchange membrane, a cation exchange membrane, an osmotic membrane, and an open gasket are stacked in multiple stages (right). FIG. 16 is a cross-sectional view of a water electrolysis device according to another embodiment of the present invention. FIG. 17 is a diagram showing the combined state of the water electrolysis device illustrated in FIG. 16 (left) and the state in which an anion exchange membrane, a cation exchange membrane, an osmotic membrane, and a closed gasket are stacked in multiple stages (right). FIG. 18 is a diagram showing the combined state of the water electrolysis device illustrated in FIG. 16 (left) and the state in which an anion exchange membrane, a cation exchange membrane, an osmotic membrane, and an open gasket are stacked in multiple stages (right). FIG. 19 is the result of verifying the energy consumption of a water electrolysis device according to one embodiment of the present invention. Specific details for implementing the invention

[0026] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, and should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0027] In addition, identical or corresponding components are assigned the same or similar reference numbers regardless of drawing symbols, and redundant descriptions thereof are omitted; furthermore, for the convenience of explanation, the size and shape of each illustrated component may be exaggerated or reduced.

[0028] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0029] As one embodiment for achieving the above objective, the present invention

[0030] A cathode electrode and an anode electrode facing each other;

[0031] An ion exchange membrane stack arranged between the cathode electrode and the anode electrode, wherein an anion exchange membrane and a cation exchange membrane are alternately arranged so as to be partitioned into a plurality of first flow paths through which a first solution flows and second flow paths through which a second solution containing a salt with a higher concentration than the first solution flows; and

[0032] A water electrolysis device is provided, comprising an electrode layer bonded to the surface of the anion exchange membrane or cation exchange membrane.

[0033] According to the U.S. Geological Survey's classification of water quality by salt concentration, 'salt water' or 'seawater' generally refers to a solution with a salt concentration of 35,000 mg / L or more, which is the salt (mainly NaCl) concentration of seawater; 'brackish water' refers to a solution with a salt concentration of about 1,000 to 10,000 mg / L; and 'fresh water' refers to a solution with a salt concentration of 0 to 1,000 mg / L.

[0034] In the present invention, the first solution may refer to a low-concentration solution having a relatively lower concentration than the second solution, and may refer to, for example, fresh water, brackish water, or seawater.

[0035] In the present invention, the second solution may refer to a high-concentration solution introduced for the generation of concentration difference or salinity difference, and may refer to, for example, seawater, seawater desalination concentrate, salt water mixed with potassium hydroxide, ammonium hydroxide, or sodium hydroxide.

[0036] In one embodiment of the present invention, the electrode layer may be configured such that a cathode (reduction reaction) and an anode (oxidation reaction) are bonded to both surfaces of an anion exchange membrane or a cation exchange membrane. The electrode layer performs the function of transferring ions through the ion exchange membrane as electrons emitted from the positive electrode move to the negative electrode.

[0037] For example, the support of the above cathode may be carbon or nickel.

[0038] For example, the catalyst of the cathode may be a noble metal catalyst such as platinum (Pt), a non-noble metal catalyst such as Ni3S, NiFeS, NiFeCoS, MoS2, Ni2N, MoN2, MoP, Ni3P, or NiMoP, or a catalyst such as RuNiMoS, PtNiMoS, which is a combination of noble and non-noble metals, but is not limited thereto.

[0039] For example, the electrode layer can be bonded to both surfaces of an anion exchange membrane or a cation exchange membrane in a zero-gap manner.

[0040] Generally, since reverse electrodialysis is based on the principle of generating voltage through the movement of ions caused by a salinity difference across an ion exchange membrane, and water electrolysis is based on the principle of moving ions by applying voltage across an ion exchange membrane, there is no known research on integrating reverse electrodialysis and water electrolysis into a single unit.

[0041] The present invention relates to a device comprising reverse electrodialysis and water electrolysis as an integrated unit. By aligning the direction of ion flow generated by applying voltage in water electrolysis with the direction of ion flow that generates voltage in reverse electrodialysis, the magnitude of the applied voltage is reduced while the amount of ion flow is simultaneously increased. Consequently, the amount of current density can be increased (current density due to applied voltage + current density due to concentration difference), thereby creating mutual synergy.

[0042] Hereinafter, a water electrolysis device according to an embodiment of the present invention will be described with reference to the attached drawings.

[0043] First, with reference to FIG. 1, a water electrolysis device (10) according to a first embodiment of the present invention will be described. The water electrolysis device according to the first embodiment of the present invention includes an anode electrode (100) and a cathode electrode (200) installed facing each other. An ion exchange membrane stack (300) is disposed between the anode electrode (100) and the cathode electrode (200). In the ion exchange membrane stack (300), an anion exchange membrane (400) and a cation exchange membrane (500) are alternately arranged so that a first flow path (310) through which a first solution of low concentration flows and a second flow path (320) through which a second solution of higher concentration than the first solution flows are divided into multiple sections. An electrode layer (600) is bonded to the surface of the anion exchange membrane (400).

[0044] The above electrode layer (600) is composed of a combination of a positive electrode and a negative electrode, and performs the role of transferring ions through an ion exchange membrane as electrons emitted from the positive electrode move to the negative electrode.

[0045] A first flow path (310) may be formed between an anion exchange membrane (400) to which an electrode layer (600) is bonded and a cation exchange membrane (500) adjacent to the anion exchange membrane (400) in the direction of the anode electrode (100).

[0046] A second flow path (320) may be formed between an anion exchange membrane (400) to which an electrode layer (600) is bonded and an adjacent cation exchange membrane (500) in the direction from the anion exchange membrane (400) toward the cathode electrode (200).

[0047] In one embodiment of the present invention, at least one gasket (800) is mounted on each end of the cation exchange membrane (500) and the anion exchange membrane (400), and the gasket (800) may be arranged to intersect each other at both ends of the cation exchange membrane (500) and the anion exchange membrane (400) to form a first flow path (310) through which a first solution flows and a second flow path (320) through which a second solution flows.

[0048] In the present invention, a spacer having an open area inside the gasket (800) can be used to prevent contact between the cation exchange membrane (500) and the anion exchange membrane (400) and to secure a flow path.

[0049] In one embodiment of the present invention, an electrode solution may be supplied to the anode electrode. Fresh water or a separate anode electrode solution may be used as the electrode solution.

[0050] At this time, water (H2O) in the second Euro (320) undergoes a reduction reaction on the negative electrode surface of the electrode layer (600) to produce hydrogen ions (H + ) and hydroxide ions (OH - It decomposes into ), and the generated hydrogen ions (H + ) is electrons (e) emitted from the positive electrode of the electrode layer (600) - It receives ) and is generated into hydrogen gas, and the generated hydroxide ions (OH - ) moves to the first channel (310) through the anion exchange membrane (400). The moved hydroxide ions (OH) - ) is oxygen (O2), water (H2O) and electrons (e) by an oxidation reaction on the positive electrode surface of the electrode layer (600). - It generates ), and the generated electrons move to the second euro (320) to produce hydrogen ions (H + It reacts with ) to produce hydrogen (H2).

[0051] Additionally, by reverse electrodialysis, the anions of the second solution move to the first flow path (310) in the direction of the anode electrode (100) through the anion exchange membrane to which the electrode layer (600) is attached, and the cations of the second solution move to the first flow path (310) through the cation exchange membrane (500) in the direction of the cathode electrode (200), and voltage and current are produced by the movement of ions. Also, electricity is produced as electrons delivered to the anode electrode (100) move to the cathode electrode (200).

[0052] FIGS. 2 and FIGS. 3 are drawings showing the combined state (left) of the water electrolysis device (10) illustrated in FIG. 1 and the state in which an anion exchange membrane (400), a cation exchange membrane (500), and a gasket (800) are stacked in multiple stages (right). The gasket in FIG. 2 is a closed type, and the gasket in FIG. 3 is an open type. The closed type gasket is suitable for manufacturing a unit stack, and the open type gasket is suitable for modularizing multiple stacks.

[0053] Next, with reference to FIG. 4, a water electrolysis device (20) according to a second embodiment of the present invention will be described. The water electrolysis device (20) according to the second embodiment of the present invention includes a cathode electrode (200) and an anode electrode (100) installed facing each other. An ion exchange membrane stack (300) is disposed between the cathode electrode (200) and the anode electrode (100). The ion exchange membrane stack (300) is configured such that a first flow path (310) through which a first solution of low concentration flows and a second flow path (320) through which a second solution of higher concentration than the first solution flows are alternately arranged with an anion exchange membrane (400) and a cation exchange membrane (500). An electrode layer (600) is bonded to the surface of the cation exchange membrane (500).

[0054] A first flow path (310) may be formed between a cation exchange membrane (500) to which an electrode layer (600) is bonded, and an anion exchange membrane (400) adjacent to the cation exchange membrane (500) in the direction of the cathode electrode (200).

[0055] The electrode layer (600) is composed of a combination of a positive electrode and a negative electrode, and performs the role of transferring ions through an ion exchange membrane as electrons emitted from the positive electrode move to the negative electrode.

[0056] A second flow path (320) may be formed between a cation exchange membrane (500) to which an electrode layer (600) is bonded, and an anion exchange membrane (400) adjacent to the cation exchange membrane (500) in the direction of the anode electrode (100).

[0057] In one embodiment of the present invention, at least one gasket (800) is mounted on each end of the cation exchange membrane (500) and the anion exchange membrane (400), and the gasket (800) may be arranged to intersect each other at both ends of the cation exchange membrane (500) and the anion exchange membrane (400) to form a first flow path (310) through which a first solution flows and a second flow path (320) through which a second solution flows.

[0058] In the present invention, a spacer having an open area inside the gasket can be used to prevent contact between the cation exchange membrane (500) and the anion exchange membrane (400) and to secure a flow path.

[0059] In one embodiment of the present invention, an electrode solution may be supplied to the anode electrode. Fresh water or a separate anode electrode solution may be used as the electrode solution.

[0060] At this time, water (H2O) in the second Euro (320) is converted into oxygen (O2) and water by an oxidation reaction on the positive electrode surface of the electrode layer (600), and electrons (e - ) emits, and at the same time hydrogen ions (H + ) moves to the first flow path (310) through the cation exchange membrane (500). At this time, hydrogen ions (H) are produced by a reduction reaction on the negative electrode surface of the electrode layer (600). + ) is additionally generated, and at the same time, hydroxide ions (OH) - It is decomposed into ) hydrogen ions (H) transferred from the cation exchange membrane (500). + ) and hydrogen ions (H) produced at the negative electrode of the electrode layer (600) + ) refers to electrons (e) flowing into the negative electrode of the electrode layer (600). - It receives ) and is converted into hydrogen gas (H2). The produced hydroxide ions (OH) - ) is transferred to a second flow path (320) in the direction of the cathode electrode (200) through an anion exchange membrane (400), and the anions in the second flow path (320) are transferred to a first flow path in the direction of the anode electrode (100) through anion exchange membrane (400).

[0061] Additionally, by reverse electrodialysis, the cations of the second solution move to the first flow path (310) through the cation exchange membrane (500) to which the electrode layer (600) is attached, and the anions of the second solution move to the first flow path (310) in the direction of the anode electrode (100) through the anion exchange membrane (400) in the direction of the anode electrode (100), and voltage and current are generated by the movement of ions. Also, electricity is produced as electrons delivered to the anode electrode (100) move to the cathode electrode (200).

[0062] FIGS. 5 and 6 are drawings showing the combined state (left) of the water electrolysis device (20) shown in FIG. 4 and the multi-stage stacked state (right) of the anion exchange membrane (400), cation exchange membrane (500), and gasket (800), wherein the gasket in FIG. 5 is closed and the gasket in FIG. 6 is open.

[0063] Closed gaskets are suitable for manufacturing unit stacks, while open gaskets are suitable for modularizing multiple stacks.

[0064] As another embodiment for achieving the above objective, the present invention

[0065] A cathode electrode (200) and an anode electrode (100) facing each other;

[0066] An ion exchange membrane stack (300) arranged between the cathode electrode (200) and the anode electrode (100); wherein an anion exchange membrane (400), a cation exchange membrane (500), and an osmotic membrane (700) are alternately arranged to form a plurality of partitions, such that a first flow path (310) through which a first solution flows, a second flow path (320) through which a second solution containing a higher concentration of salt than the first solution flows, and a third flow path (330) through which seawater flows.

[0067] A water electrolysis device is provided, comprising an electrode layer (600) bonded to the surface of the anion exchange membrane (400) or the cation exchange membrane (500).

[0068] Referring to FIG. 7, a water electrolysis device (30) according to a third embodiment of the present invention is described. The water electrolysis device according to the third embodiment of the present invention includes a cathode electrode (200) and an anode electrode (100) facing each other. An ion exchange membrane stack (300) is disposed between the cathode electrode (200) and the anode electrode (100). The ion exchange membrane stack (300) is configured such that a first flow path (310) through which a first solution flows, a second flow path (320) through which a second solution containing a higher concentration of salt than the first solution flows, and a third flow path (330) through which seawater flows are alternately arranged with an anion exchange membrane (400), a cation exchange membrane (500), and an osmotic membrane (700). An electrode layer (600) is bonded to the surface of the anion exchange membrane (400). The above osmotic membrane (700) is located between the anion exchange membrane (400) and the cation exchange membrane (500) which is located adjacent to the anion exchange membrane (400) and positioned in a direction toward the cathode electrode (200).

[0069] A first flow path (310) may be formed between an anion exchange membrane (400) to which an electrode layer (600) is bonded and a cation exchange membrane (500) adjacent to the anion exchange membrane (400) in the direction of the anode electrode (100).

[0070] A second flow path (320) may be formed between the anion exchange membrane (400) to which the electrode layer (600) is bonded and the osmotic membrane (700) adjacent to the anion exchange membrane (400).

[0071] The third channel (330) is formed between the osmotic membrane (700) and the cation exchange membrane (500) adjacent to the osmotic membrane (700). Since seawater flowing in the third channel (330) can corrode the catalyst of the electrode layer (600) if it comes into direct contact with the electrode layer (600) bonded to the surface of the anion exchange membrane (400), the osmotic membrane (700) is placed between the anion exchange membrane (400) and the third channel (330) to prevent direct contact.

[0072] In one embodiment of the present invention, at least one gasket (800) is installed at each of the two ends of the cation exchange membrane (500), the anion exchange membrane (400), and the osmotic membrane (700), and the gasket (800) may be arranged to intersect each other at both ends of the cation exchange membrane (500) and the anion exchange membrane (400) to form a first flow path (310) through which a first solution flows, a second flow path (320) through which a second solution flows, and a third flow path (330) through which a third solution flows.

[0073] In the present invention, a spacer having an open area inside the gasket can be used to prevent contact between the cation exchange membrane (500), the anion exchange membrane (400), and the osmotic membrane (700) and to secure a flow path.

[0074] In one embodiment of the present invention, an electrode solution may be supplied to the anode electrode. Fresh water or a separate anode electrode solution may be used as the electrode solution.

[0075] When water (H2O) from the seawater of the third euro (330) moves to the second euro (320) through the osmotic membrane (700), the moved water undergoes a reduction reaction on the negative electrode surface of the electrode layer (600) to produce hydrogen ions (H + ) and hydroxide ions (OH - It decomposes into the generated hydrogen ions (H + ) electrons (e) emitted from the positive electrode of the electrode layer (600) - Upon receiving ), hydrogen gas (H2) is generated, and the generated hydroxide ions (OH) - ) moves to the first channel (310) through the anion exchange membrane (400). The moved hydroxide ions (OH) - ) is converted into oxygen (O2) and water by an oxidation reaction on the positive electrode surface of the electrode layer (600), and electrons (e - It emits the generated electrons (e - ) moves to the second euro (320) and hydrogen ions (H + It reacts with ) to produce hydrogen (H2).

[0076] Additionally, by reverse electrodialysis, cations of the third solution (seawater) move to the first flow path through the cation exchange membrane (500) in the direction of the cathode electrode (200). Anions of the second solution move to the first flow path (310) through the anion exchange membrane (400) to which the electrode layer (600) is attached. Voltage and current are generated by this movement of ions. Additionally, electricity is generated as electrons delivered to the anode electrode (100) move to the cathode electrode (200). At this time, the cations that have moved through the cation exchange membrane (500) in the direction of the cathode electrode (200) may come into direct contact with the anion exchange membrane (400), but do not cause corrosion.

[0077] FIGS. 8 and 9 are drawings showing the combined state (left) of the water electrolysis device (30) shown in FIG. 7 and the state in which an anion exchange membrane (400), a cation exchange membrane (500), an osmotic membrane (700) and a gasket (800) are stacked in multiple stages (right), wherein the gasket in FIG. 8 is closed and the gasket in FIG. 9 is open.

[0078] Closed gaskets are suitable for manufacturing unit stacks, while open gaskets are suitable for modularizing multiple stacks.

[0079] Referring to FIG. 10, a water electrolysis device (40) according to a fourth embodiment of the present invention is described. The water electrolysis device according to the fourth embodiment of the present invention includes a cathode electrode (200) and an anode electrode (100) facing each other. An ion exchange membrane stack (300) is disposed between the cathode electrode (200) and the anode electrode (100). The ion exchange membrane stack (300) is configured such that a first flow path (310) through which a first solution flows, a second flow path (320) through which a second solution containing a higher concentration of salt than the first solution flows, and a third flow path (320) through which seawater flows are alternately arranged with an anion exchange membrane (400), a cation exchange membrane (500), and an osmotic membrane (700). An electrode layer (600) is bonded to the surface of the cation exchange membrane (500). The above osmotic membrane (700) is located between the above cation exchange membrane (500) and the anion exchange membrane (400) which is located adjacent to the above cation exchange membrane (500) and positioned in a direction toward the anode electrode (100).

[0080] A first flow path (310) may be formed between a cation exchange membrane (500) to which an electrode layer (600) is bonded, and an anion exchange membrane (400) adjacent to the cation exchange membrane (500) in the direction of the cathode electrode (200).

[0081] A second flow path (320) may be formed between the cation exchange membrane (500) to which the electrode layer (600) is bonded and the osmotic membrane (700) adjacent to the cation exchange membrane (500).

[0082] In one embodiment of the present invention, at least one gasket (800) is installed at each of the two ends of the cation exchange membrane (500), the anion exchange membrane (400), and the osmotic membrane (700), and the gasket (800) may be arranged to intersect each other at both ends of the cation exchange membrane (500) and the anion exchange membrane (400) to form a first flow path (310) through which a first solution flows, a second flow path (320) through which a second solution flows, and a third flow path (330) through which a third solution flows.

[0083] In the present invention, a spacer having an open area inside the gasket can be used to prevent contact between the cation exchange membrane (500), the anion exchange membrane (400), and the osmotic membrane (700) and to secure a flow path.

[0084] In one embodiment of the present invention, an electrode solution may be supplied to the anode electrode. Fresh water or a separate anode electrode solution may be used as the electrode solution.

[0085] The third channel (330) is formed between the osmotic membrane (700) and the anion exchange membrane (400) adjacent to the osmotic membrane (700). At this time, when water (H2O) from the seawater in the third channel (330) moves to the second channel (320) through the osmotic membrane (700), the water (H2O) in the second channel (320) is converted into oxygen (O2) and water (H2O) by an oxidation reaction on the positive electrode surface of the electrode layer (600), and electrons (e - ) is emitted. At this time, hydrogen ions are additionally produced by a reduction reaction on the negative electrode surface of the electrode layer (600) in the first flow path (310), and at the same time, hydroxide ions (OH) - It is decomposed into ). Hydrogen ions (H) transferred from the second euro (320) to the first euro (310) through the cation exchange membrane (500). + ) and hydrogen ions (H) produced at the negative electrode of the electrode layer (600) in the first Euro (310) + ) refers to electrons (e) flowing into the negative electrode of the electrode layer (600). - It receives ) and is converted into hydrogen gas (H2). Hydroxide ions (OH) produced in the first euro - ) is transferred to the third flow path (330) through the anion exchange membrane (400), and the anions in the third flow path (330) are transferred to the first flow path (310) through the anion exchange membrane (400). At this time, Cl, which is an anion, is applied to the reduction electrode of the electrode layer (600) of the cation exchange membrane (500). - The solution comes into contact with the electrode, and the first solution is alkalized by the reduction electrode reaction ( P H>9) can be, but Cl- The ions play a positive role in returning the first solution, which has been alkalized, back to a neutral state, so the electrode does not corrode.

[0086] Additionally, by reverse electrodialysis, the cations of the second solution move to the first flow path (310) through the cation exchange membrane (500) to which the electrode layer (600) is attached. The anions of the third solution (seawater) move to the first flow path (310) through the anion exchange membrane (400) in the direction of the anode electrode (100). Voltage and an electric field are generated by this movement of ions. Additionally, electricity is produced as electrons delivered to the anode electrode (100) move to the cathode electrode (200).

[0087] In one embodiment of the present invention, an osmotic membrane (700) may be arranged between each cation exchange membrane (500) and an anion exchange membrane (400).

[0088] FIGS. 11 and FIGS. 12 are drawings showing the combined state (left) of the water electrolysis device (40) shown in FIG. 10 and the state in which an anion exchange membrane (400), a cation exchange membrane (500), an osmotic membrane (700) and a gasket (800) are stacked in multiple stages (right), wherein the gasket in FIG. 11 is closed and the gasket in FIG. 12 is open.

[0089] Closed gaskets are suitable for manufacturing unit stacks, while open gaskets are suitable for modularizing multiple stacks.

[0090] Referring to FIG. 13, a water electrolysis device (50) according to the fifth embodiment of the present invention is described. The water electrolysis device according to the fifth embodiment of the present invention includes a cathode electrode (200) and an anode electrode (100) facing each other. An ion exchange membrane stack (300) is disposed between the cathode electrode (200) and the anode electrode (100). The ion exchange membrane stack (300) is configured such that a first flow path (310) through which a first solution flows, a second flow path through which a second solution (320) containing a higher concentration of salt than the first solution flows, and a third flow path (330) through which seawater flows are alternately arranged with an anion exchange membrane (400), a cation exchange membrane (500), and an osmotic membrane (700). An electrode layer (600) is bonded to the surface of the anion exchange membrane (400). The above osmotic membrane (700) is arranged between the above cation exchange membrane (500) and anion exchange membrane (400).

[0091] A first flow path (310) may be formed between a cation exchange membrane (500) and an adjacent osmotic membrane (700) in the direction from the cation exchange membrane (500) toward the cathode electrode (200).

[0092] A second flow path (320) may be formed between an anion exchange membrane (400) to which an electrode layer (600) is bonded and an adjacent osmotic membrane (700). At this time, the second flow path (320) formed between the adjacent osmotic membrane (700) in the direction of the anode electrode (100) of the anion exchange membrane (400) is called the second-1 flow path (321), and the second flow path (320) formed between the adjacent osmotic membrane (700) in the direction of the cathode electrode (200) of the anion exchange membrane (400) is called the second-2 flow path (322).

[0093] A third flow path (330) may be formed between the osmotic membrane (700) and the adjacent cation exchange membrane (500) in the direction from the osmotic membrane (700) toward the cathode electrode (200).

[0094] In one embodiment of the present invention, at least one gasket (800) is installed at each of the two ends of the cation exchange membrane (500), the anion exchange membrane (400), and the osmotic membrane (700), and the gasket (800) may be arranged to intersect each other at both ends of the cation exchange membrane (500) and the anion exchange membrane (400) to form a first flow path (310) through which a first solution flows, a second flow path (320) through which a second solution flows, and a third flow path (330) through which a third solution flows.

[0095] In the present invention, a spacer having an open area inside the gasket can be used to prevent contact between the cation exchange membrane (500), the anion exchange membrane (400), and the osmotic membrane (700) and to secure a flow path.

[0096] In one embodiment of the present invention, an electrode solution may be supplied to the anode electrode. Fresh water or a separate anode electrode solution may be used as the electrode solution.

[0097] At this time, water (H2O) from the first euro (310) moves to the second-1 euro (321) through the osmotic membrane (700), and water (H2O) from the seawater of the third euro (330) moves to the second-2 euro (322) through the osmotic membrane (700).

[0098] Water that has moved to the 2-2 Euro (322) undergoes a reduction reaction on the negative electrode surface of the electrode layer (600) to produce hydrogen ions (H + ) and hydroxide ions (OH - It is decomposed into ), and the generated hydrogen ions are electrons (e e emitted from the positive electrode of the electrode layer (600) - It receives ) and is released as hydrogen gas (H2), and the generated hydroxide ions (OH) - ) moves through the anion exchange membrane (400) to the 2-1 (321) channel. The moved hydroxide ions (OH) - ) is converted into oxygen (O2) and water (H2O) by an oxidation reaction on the positive electrode surface of the electrode layer (600), and electrons (e -) is generated. The water (H2O) that moved to the 2-1 Euro (321) is used to produce oxygen in the oxidation reaction. The generated electrons move to the 2-2 Euro (322) and hydrogen ions (H + It reacts with ) to produce hydrogen (H2).

[0099] Additionally, by reverse electrodialysis, cations of the third solution (seawater) move through the cation exchange membrane (500) in the direction of the cathode electrode (200), and anions of the second-2 flow path (322) move to the second-1 flow path (321) through the anion exchange membrane (400) to which the electrode layer (600) is attached. Voltage and current are generated by this movement of ions. In addition, electricity is produced as electrons delivered to the anode electrode (100) move to the cathode electrode (200).

[0100] FIGS. 14 and FIGS. 15 are drawings showing the combined state (left) of the water electrolysis device (50) shown in FIG. 13 and the state in which an anion exchange membrane (400), a cation exchange membrane (500), an osmotic membrane (700) and a gasket (800) are stacked in multiple stages (right), wherein the gasket in FIG. 14 is closed and the gasket in FIG. 15 is open.

[0101] Closed gaskets are suitable for manufacturing unit stacks, while open gaskets are suitable for modularizing multiple stacks.

[0102] Referring to FIG. 16, a water electrolysis device (60) according to the sixth embodiment of the present invention is described. The water electrolysis device according to the sixth embodiment of the present invention includes a cathode electrode (200) and an anode electrode (100) facing each other. An ion exchange membrane stack (300) is disposed between the cathode electrode (200) and the anode electrode (100). The ion exchange membrane stack (300) is configured such that a first flow path (310) through which a first solution flows, a second flow path (320) through which a second solution containing a higher concentration of salt than the first solution flows, and a third flow path (330) through which seawater flows are alternately arranged with an anion exchange membrane (400), a cation exchange membrane (500), and an osmotic membrane (700). An electrode layer (600) is bonded to the surface of the cation exchange membrane (500). The above osmotic membrane (700) is arranged between the above cation exchange membrane (500) and anion exchange membrane (400).

[0103] A first flow path (310) may be formed between the anion exchange membrane (400) and the adjacent osmotic membrane (700) in the direction of the anode electrode (100) from the cation exchange membrane (500).

[0104] A second flow path (320) may be formed between the cation exchange membrane (500) to which the electrode layer (600) is bonded and the adjacent osmotic membrane (700). At this time, the second flow path (320) formed between the adjacent osmotic membrane (700) in the direction of the anode electrode (100) of the cation exchange membrane (500) is called the second-1 flow path (321), and the second flow path (320) formed between the adjacent osmotic membrane (700) in the direction of the cathode electrode (200) of the cation exchange membrane (500) is called the second-2 flow path (322).

[0105] A third channel (330) may be formed between the osmotic membrane (700) and an adjacent anion exchange membrane (400) in the direction from the osmotic membrane (700) toward the anode electrode (100).

[0106] In one embodiment of the present invention, at least one gasket (800) is installed at each of the two ends of the cation exchange membrane (500), the anion exchange membrane (400), and the osmotic membrane (700), and the gasket (800) may be arranged to intersect each other at both ends of the cation exchange membrane (500) and the anion exchange membrane (400) to form a first flow path (310) through which a first solution flows, a second flow path (320) through which a second solution flows, and a third flow path (330) through which a third solution flows.

[0107] In the present invention, a spacer having an open area inside the gasket can be used to prevent contact between the cation exchange membrane (500), the anion exchange membrane (400), and the osmotic membrane (700) and to secure a flow path.

[0108] In one embodiment of the present invention, an electrode solution may be supplied to the anode electrode. Fresh water or a separate anode electrode solution may be used as the electrode solution.

[0109] At this time, water (H2O) from the seawater of the third euro (330) moves to the second-1 euro (321) through the osmotic membrane (700), and water (H2O) from the first euro (310) moves to the second-2 euro (322) through the osmotic membrane (700).

[0110] Water (H2O) in the second-1 Euro (321) is converted into oxygen (O2) and water (H2O) by an oxidation reaction on the positive electrode surface of the electrode layer (600), and electrons (e - It emits ) and simultaneously hydrogen ions (H + ) moves to the second-2 channel (322) through the cation exchange membrane (500). At this time, hydrogen ions (H) in the second-2 channel (322) are reduced by a reduction reaction on the negative electrode surface of the electrode layer (600). + ) is additionally produced, and at the same time, hydroxide ions (OH) - It is decomposed into ). Hydrogen ions (H) transferred to the 2-2 Euro (322) through the cation exchange membrane (500) + ) and hydrogen ions (H) produced on the negative electrode surface +) is electrons (e) flowing in from the negative electrode of the electrode layer (600) - It is converted into hydrogen gas (H2) by receiving it. In addition, the negative ions of the third euro (330) are transferred to the first euro (310) through the negative ion exchange membrane (400).

[0111] By reverse electrodialysis, the direction of movement of the cations in the second solution is determined by the concentration difference between the second-1 channel (321) and the second-2 channel (322).

[0112] The anions of the third solution (seawater) move through the anion exchange membrane (400) in the direction of the anode electrode (100), and voltage and current are generated by this movement of ions. In addition, electricity is produced as electrons delivered to the anode electrode (100) move to the cathode electrode (200).

[0113] FIGS. 17 and 18 are drawings showing the combined state (left) of the water electrolysis device (60) shown in FIG. 16 and the state in which an anion exchange membrane (400), a cation exchange membrane (500), an osmotic membrane (700) and a gasket (800) are stacked in multiple stages (right), wherein the gasket in FIG. 17 is closed and the gasket in FIG. 18 is open.

[0114] Closed gaskets are suitable for manufacturing unit stacks, while open gaskets are suitable for modularizing multiple stacks.

[0116] Experimental Example

[0117] 1. Device manufacturing

[0118] A water electrolysis device according to the first embodiment of the present invention was manufactured. Specifically, for reverse electrodialysis (RED), an anion exchange membrane and a cation exchange membrane with a thickness of 16 μm, developed in-house by the Korea Institute of Energy Research, were used. A 0.5 M NaOH aqueous solution at 20°C was used as the high-concentration solution. 0.0017 M water was used as the low-concentration solution. A Ru / Ir on Ti mesh was used as the positive electrode (anode electrode) to be used in the electrode layer, and a Pt on Ti mesh was used as the negative electrode (cathode electrode). A 50 mM ferropericyanide solution was used as the electrode solution for reverse electrodialysis.

[0119] For water electrolysis using the anion exchange membrane (AEM) method, on the right side of the reverse electrodialysis anion exchange membrane, i) a water electrolysis (WE1) with a positive electrode (1) and a negative electrode (1) using Ni foam, and ii) a water electrolysis (WE2) with a positive electrode (2) and a negative electrode (2) using Co2Fe2N2on Ni foam of the nitride alloy series were manufactured. Subsequently, 10 cells were stacked for an integrated reverse electrodialysis / AEM water electrolysis experiment, and low-concentration and high-concentration solutions were supplied to the hybrid stack at 100 ml / min, and the electrode solution at 50 ml / min.

[0120] The following is a description of the process for each condition.

[0121] 1) WE1 - Standalone operation of anion exchange membrane water electrolysis using a configuration in which a combination of electrodes of a positive electrode (1) and a negative electrode (1) is bonded to the surface of an anion exchange membrane

[0122] 2) Standalone operation of reverse electrodialysis combined with RED1 - WE1

[0123] 3) WE1+RED1 - Simultaneous operation of WE1 and reverse electrodialysis in WE1-combined reverse electrodialysis

[0124] 4) WE2 - Standalone operation of anion exchange membrane water electrolysis using a configuration in which the electrode combination of the positive electrode (2) and the negative electrode (2) is bonded to the surface of the anion exchange membrane

[0125] 5) Standalone operation of reverse electrodialysis combined with RED2 - WE2

[0126] 6) WE2+RED2 - Simultaneous operation of WE2 and reverse electrodialysis in WE2 combined reverse electrodialysis

[0128] 2. Energy consumption evaluation

[0129] Figure 19 compares experimental results regarding the energy consumption of a water electrolysis device according to an embodiment of the present invention.

[0130] In the case of WE1, which uses only AEM water electrolysis with a relatively low catalytic activity pure Ni foam as a catalyst, the energy consumed to produce 1 kg-H2 was measured to be 65 kWh / kg-H2. On the other hand, in the case of WE1+RED1, which simultaneously performed the same AEM water electrolysis system and reverse electrodialysis, the energy consumed was found to be approximately 47 kWh / kg-H2. It was confirmed that energy consumption could be reduced by approximately 18 kWh / kg-H2 through the combined performance of reverse electrodialysis.

[0131] In the case of WE2, which utilized only AEM water electrolysis with a catalyst structure in which metal nitride (Co2Fe2N2) nanoparticles with excellent catalytic activity were directly synthesized on the surface of pure Ni foam, the energy consumed to produce 1 kg-H2 was measured to be 42 kWh / kg-H2. This figure represents a reduction in energy consumption of 22 kWh / kg-H2 compared to WE1, which is attributed to the increased catalytic activity. Additionally, in the case of WE2+RED2, which performed the aforementioned AEM water electrolysis and reverse electrodialysis simultaneously, the energy consumption was found to be approximately 26 kWh / kg-H2. Through the combined performance of reverse electrodialysis, an additional reduction in energy consumption of 22 kWh / kg-H2 was confirmed.

[0132] As a result, it was confirmed that energy consumption can be significantly reduced when water electrolysis and reverse electrodialysis are performed simultaneously compared to when water electrolysis is performed alone.

[0133] In addition, considering that the energy consumption of a recently reported traditional single-unit water electrolysis stack is 45-65 kWh / kg-H2, the reverse electrodialysis / AEM water electrolysis combined process (WE2+RED2) of the present invention was found to be able to save up to 50% of energy with an energy consumption of 26 kWh / kg-H2.

[0134] From the foregoing description, those skilled in the art to which the present invention pertains will understand that the present invention may be implemented in other specific forms without altering its technical concept or essential features. In this regard, the embodiments described above should be understood as illustrative in all respects and not restrictive. The scope of the present invention should be interpreted as including all modifications or variations derived from the meaning and scope of the claims set forth below and their equivalents, rather than from the detailed description above. Explanation of the symbols

[0136] 10, 20, 30, 40, 50, 60: Water electrolysis device 100: Anode electrode 200: Cathode electrode 300 : Ion exchange membrane stack 310 : 1 Euro 320 : 2nd Euro 321 : 2-1 Euro 322 : 2-2 Euro 330 : 3rd Euro 400 : Anion exchange membrane 500: Cation exchange membrane 600 : Electrode layer 700 : Osmotic membrane 800 : Gasket

Claims

Claim 1 A water electrolysis device comprising: a cathode electrode and an anode electrode facing each other; an ion exchange membrane stack arranged between the cathode electrode and the anode electrode, wherein an anion exchange membrane and a cation exchange membrane are alternately arranged to form a plurality of first flow paths through which a first solution flows and second flow paths through which a second solution containing a salt with a higher concentration than the first solution flows; and an electrode layer directly bonded to the surface of the anion exchange membrane or the cation exchange membrane. Claim 2 A water electrolysis device according to claim 1, wherein when the electrode layer is bonded to the surface of an anion exchange membrane, a cation exchange membrane is disposed adjacent to the anion exchange membrane at each of the cathode electrode and the anode electrode, respectively. Claim 3 A water electrolysis device according to claim 1, wherein when the electrode layer is bonded to the surface of a cation exchange membrane, an anion exchange membrane is disposed adjacent to the cathode electrode and an anode electrode, respectively, than the cation exchange membrane. Claim 4 A water electrolysis device according to claim 1, wherein at least one gasket is installed at each of the two ends of the cation exchange membrane and the anion exchange membrane, and the gasket is arranged to intersect each other at both ends of the cation exchange membrane and the anion exchange membrane to form a first flow path through which a first solution flows and a second flow path through which a second solution flows. Claim 5 A water electrolysis device comprising: a cathode electrode and an anode electrode facing each other; an ion exchange membrane stack arranged between the cathode electrode and the anode electrode, wherein an anion exchange membrane, a cation exchange membrane, and an osmotic membrane are alternately arranged to form a plurality of channels, each channel being divided into a first channel through which a first solution flows, a second channel through which a second solution containing a higher concentration of salt than the first solution flows, and a third channel through which seawater flows; and an electrode layer directly bonded to the surface of the anion exchange membrane or the cation exchange membrane, wherein the electrode layer is configured to perform a water electrolysis reaction using seawater flowing through the third channel. Claim 6 A water electrolysis device according to claim 5, wherein when the electrode layer is bonded to the surface of the anion exchange membrane, the osmotic membrane is located between the anion exchange membrane and a cation exchange membrane positioned adjacent to the anion exchange membrane and arranged in a direction toward the cathode electrode. Claim 7 In claim 6, the above third flow path is formed between the above osmotic membrane and the cation exchange membrane adjacent to the above osmotic membrane, in a water electrolysis device. Claim 8 A water electrolysis device according to claim 5, wherein when the electrode layer is bonded to the surface of the cation exchange membrane, the osmotic membrane is located between the cation exchange membrane and an anion exchange membrane positioned adjacent to the cation exchange membrane and arranged in a direction toward the anode electrode. Claim 9 In claim 8, the water electrolysis device, wherein the third flow path is formed between the osmotic membrane and an anion exchange membrane adjacent to the osmotic membrane. Claim 10 In claim 5, a water electrolysis device having an osmotic membrane arranged between the cation exchange membrane and the anion exchange membrane. Claim 11 ◈Claim 11 was abandoned upon payment of the registration fee.◈ A water electrolysis device according to Claim 10, wherein when the electrode layer is bonded to the surface of the anion exchange membrane, the third flow path is formed between an osmotic membrane and a cation exchange membrane positioned adjacent to the osmotic membrane and arranged in a direction toward the cathode electrode. Claim 12 ◈Claim 12 was abandoned upon payment of the registration fee.◈ A water electrolysis device according to Claim 10, wherein when the electrode layer is bonded to the surface of the cation exchange membrane, the third flow path is formed between an osmotic membrane and an anion exchange membrane positioned adjacent to the osmotic membrane and arranged in a direction toward the anode electrode.

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