Alkaline water electrolysis device including metal powder fluid electrodes

Abstract

The present invention discloses a water electrolysis device including a metal powder fluid electrode, which includes a cathode, a first flow channel formed on the cathode, a cation exchange membrane (CEM) formed on the first flow channel, a second flow channel formed on the CEM, and an anode formed on the second flow channel, wherein the second flow channel contains metal powder and is used as a metal powder fluid electrode.

Description

[Technical Field]

[0001] The present invention relates to an alkaline water electrolysis device including a metal powder fluid electrode, and more specifically to an alkaline water electrolysis device including an ultra-low power metal powder fluid electrode that uses a metal oxidation reaction, which is capable of producing hydrogen gas by inducing an oxidation reaction of metal in a fluidized bed containing metal powder to metal ions at the anode and causing a water splitting reaction at the cathode. [Background technology]

[0002] In the oxygen evolution (OER) reaction that occurs at the anode of solid polymer water electrolysis, four electrons are involved in the reaction, resulting in a high overpotential when voltage is applied. The expensive catalysts (iridium / platinum) used due to the overpotential and the strong acidity of the solid polymer electrolyte have drawbacks such as high installation costs and poor durability.

[0003] Due to these drawbacks, solid polymer water electrolysis is still in the technological development stage, and alkaline water electrolysis is the only commercially available water electrolysis technology. However, even alkaline water electrolysis is about three times more expensive than hydrogen production using fossil fuels, a difference that cannot be overcome by improving the efficiency of electrolyzers alone.

[0004] Commercial water electrolysis is designed to simultaneously generate hydrogen and oxygen. The cell configuration, which minimizes the distance between the electrodes and the ion exchange membrane to reduce resistance, causes hydrogen and oxygen to mix, and the resulting mixed gas easily reaches its flammability limit, increasing the risk of explosion. Therefore, existing water electrolysis technologies have always raised safety concerns and have drawbacks, such as the need to include a separator membrane to prevent mixing of hydrogen and oxygen or an additional process to adjust the pressure in the hydrogen and oxygen generation channels.

[0005] Even in the case of separated water electrolysis, which alleviates the risk of an oxygen-hydrogen mixture explosion, the oxygen generating reaction is ultimately separated without being eliminated, and oxygen, a risk factor for explosion, is generated, so the possibility of an explosion cannot be completely eliminated.Furthermore, separated water electrolysis offers cost benefits by removing the ion exchange membrane from the process, but adds a redox mediator process, making it a water electrolysis method that does not achieve cost recovery through additional products, even though it offers significant cost benefits. Summary of the Invention [Problem to be solved by the invention]

[0006] Each embodiment of the present invention is intended to provide an ultra-low power alkaline water electrolysis device including a metal powder fluid electrode using a metal oxidation reaction, which uses a metal powder fluid electrode containing metal powder to induce an oxidation reaction of a metal to metal ions in a second flow channel and cause a water splitting reaction in a first flow channel to produce hydrogen gas while simultaneously generating zinc hydroxide and / or zinc oxide particle (e.g., zinc hydroxide and / or zinc oxide nanoparticle) products.

[0007] The embodiments of the present invention are not limited to simply improving the performance / energy efficiency of a water electrolysis device, but also aim to provide an alkaline water electrolysis device including a metal powder fluid electrode that can occupy a cost advantage in line with the growing zinc oxide market through high-value-added zinc oxide synthesized as the process progresses. [Means for solving the problem]

[0008] An alkaline water electrolysis apparatus according to one embodiment of the present invention includes a cathode; a first flow channel formed on the cathode; a cation exchange membrane (CEM) formed on the first flow channel; a second flow channel formed on the CEM; and an anode formed on the second flow channel, wherein the second flow channel contains metal particles and is used as a metal particle fluidic electrode.

[0009] When a voltage is applied in a direction perpendicular to the cation exchange membrane, the metal powder is oxidized in the second flow channel to generate metal ions, and the potential difference of the alkaline water electrolysis device can be adjusted using the standard reduction potential of the metal powder.

[0010] Metal ions generated in the second flow channel can migrate to the first flow channel along the direction of the electric field.

[0011] In the first flow channel, water is decomposed into hydrogen and hydroxide ions, and the generated hydroxide ions react with the metal ions to generate at least one of a metal hydroxide and a metal oxide.

[0012] The alkaline water electrolysis device can convert the metal hydroxide into the metal oxide in the first flow channel by adjusting the operating temperature.

[0013] The operating temperature may be between 20°C and 100°C.

[0014] The metal powder may include at least one of zinc (Zn), lead (Pb), cadmium (Cd), iron (Fe), magnesium (Mg), and aluminum (Al), but is not limited thereto.

[0015] The alkaline water electrolysis device may further include a cationic polyelectrolyte layer at the interface between the cathode and the first flow channel.

[0016] An alkaline water electrolysis apparatus with a zero-gap structure according to an embodiment of the present invention includes a first flow channel; a cathode formed on the first flow channel; a cation exchange membrane formed on the cathode; an anode formed on the cation exchange membrane; and a second flow channel formed on the anode, wherein the second flow channel contains metal powder and is used as a metal powder fluid electrode.

[0017] An alkaline water electrolysis apparatus according to another embodiment of the present invention includes a cathode; a first flow channel formed on the cathode; an anion exchange membrane (AEM, anion polyelectrolyte) formed on the first flow channel; a second flow channel formed on the anion exchange membrane; and an anode formed on the second flow channel, wherein the second flow channel contains metal powder and is used as a metal powder fluid electrode.

[0018] When a voltage is applied in a direction perpendicular to the anion exchange membrane, the metal powder is oxidized in the second flow channel to generate metal ions, and the potential difference of the alkaline water electrolysis device can be adjusted using the standard reduction potential of the metal powder.

[0019] Water is split into hydrogen and hydroxide ions in the first flow channel, and the generated hydroxide ions can migrate to the second flow channel in the direction of the electric field.

[0020] In the second flow channel, the hydroxide ions may react with the metal ions to produce at least one of a metal hydroxide and a metal oxide.

[0021] The alkaline water electrolysis device can adjust the operating temperature to convert the metal hydroxide into the metal oxide in the second flow channel.

[0022] The operating temperature may be between 20°C and 100°C.

[0023] The alkaline water electrolysis device may further include an anion polyelectrolyte layer at the interface between the second flow channel and the anode. [Effects of the Invention]

[0024] Each embodiment of the present invention can provide an ultra-low power alkaline water electrolysis device including a metal powder fluid electrode, which uses a metal powder fluid electrode to induce an oxidation reaction of a metal to metal ions in a second flow channel and a water splitting reaction in a first flow channel to produce hydrogen gas while simultaneously generating zinc hydroxide and / or zinc oxide particle (e.g., zinc hydroxide and / or zinc oxide nanoparticle) products.

[0025] The embodiments of the present invention are not limited to simply improving the performance / energy efficiency of a water electrolysis device, but can also provide an alkaline water electrolysis device including a metal powder fluid electrode that can occupy a cost advantage in line with the growing zinc oxide market through high-value-added zinc oxide synthesized through the process.

[0026] Furthermore, according to the embodiments of the present invention, the ultra-low power alkaline water electrolysis device using the oxidation reaction of metal powder particles can be used not only for water electrolysis but also for fuel cells, thereby improving performance and increasing energy efficiency, and thereby responding to the growing demand for hydrogen. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a schematic diagram illustrating an alkaline water electrolysis apparatus according to an embodiment of the present invention. [Figure 2]FIG. 1 is a schematic diagram illustrating an alkaline water electrolysis apparatus including a cationic polymer electrolyte layer according to an embodiment of the present invention. [Figure 3] 1 is a schematic diagram illustrating an alkaline water electrolysis apparatus having a zero gap structure according to an embodiment of the present invention. FIG. [Figure 4] FIG. 1 is a schematic diagram illustrating an alkaline water electrolysis apparatus according to another embodiment of the present invention. [Figure 5] 1 is a microscope image showing an alkaline water electrolysis apparatus according to an embodiment of the present invention. [Figure 6] 1 is a graph showing measurement results of an open circuit voltage of an alkaline water electrolysis apparatus according to an embodiment of the present invention. [Figure 7] 1 is a microscopic image of an alkaline water electrolysis device including a cationic polymer electrolyte layer according to an embodiment of the present invention. [Figure 8] 1 is a graph showing measurement results of an open circuit voltage of an alkaline water electrolysis device including a cationic polymer electrolyte layer according to an embodiment of the present invention. [Figure 9] 1 is a microscope image showing a first flow channel including a cationic polymer electrolyte layer in an alkaline water electrolysis apparatus including a cationic polymer electrolyte layer according to an embodiment of the present invention. [Figure 10] 1 is a microscope image showing an alkaline water electrolysis device having a zero gap structure according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and the contents described in the accompanying drawings, but the present invention is not limited or restricted by the embodiments.

[0029] The terms used in this specification are for the purpose of describing the embodiments and are not intended to limit the present invention. In this specification, the singular includes the plural unless the phrase specifically states otherwise. As used in this specification, the words "comprises" and / or "comprising" refer to the presence of components, steps, operations and / or elements and do not exclude the presence or addition of one or more other components, steps, operations and / or elements.

[0030] As used herein, words such as "embodiment," "example," "aspect," "exemplary," and the like should not be construed as implying that any aspect or design described is better or more advantageous than other aspects or designs.

[0031] Also, the term "or" means "inclusive or" rather than "exclusive or." That is, unless otherwise stated or clear from the context, the phrase "x uses a or b" means any one of the natural inclusive permutations.

[0032] Additionally, the singular terms "a" or "an" as used in this specification and claims should generally be construed to mean "one or more" unless otherwise stated or unless it is clear from the context that the singular form is intended.

[0033] The terms used in the following description have been selected as being common and universal in the relevant technical field, but other terms may be used according to developments and / or changes in technology, customs, the preferences of engineers, etc. Therefore, the terms used in the following description should not be understood as limiting the technical idea, but should be understood as exemplary terms for describing the embodiments.

[0034] In addition, in certain cases, the applicant may arbitrarily select certain terms, and in such cases, the detailed meanings of these terms will be described in the relevant explanation section. Therefore, the terms used in the following explanation should be understood based on the meaning of the terms and the overall content of the specification, rather than simply the names of the terms.

[0035] Meanwhile, terms such as "first" and "second" may be used to describe various components, but each component is not limited by each term. Each term is used only to distinguish one component from another.

[0036] Furthermore, when a film, layer, region, component, or other part is said to be "on" another part, this includes not only the case where it is directly on top of the other part, but also the case where another film, layer, region, component, etc. is interposed between them.

[0037] Unless otherwise defined, all terms (including technical and scientific terms) used herein can be used in the sense that they can be commonly understood by those skilled in the art to which the present invention belongs. Furthermore, each commonly used predefined term will not be interpreted ideally or excessively unless it is clearly and specifically defined.

[0038] Meanwhile, when describing the present invention, if it is determined that a detailed description of related publicly known functions or configurations may obscure the gist of the present invention, the detailed description thereof will be omitted. Furthermore, the terminology used in this specification is used to appropriately describe embodiments of the present invention, and may vary depending on the intentions of users and operators or the practices in the field to which the present invention pertains. Therefore, the terminology should be defined based on the overall content of this specification.

[0039] FIG. 1 is a schematic diagram of an alkaline water electrolysis apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic diagram of an alkaline water electrolysis apparatus according to an embodiment of the present invention including a cationic polymer electrolyte layer.

[0040] An alkaline water electrolysis apparatus according to one embodiment of the present invention includes a cathode 110, a first flow channel 120 formed on the cathode 110, a cation exchange membrane (CEM) 130 formed on the first flow channel 120, a second flow channel 140 formed on the cation exchange membrane 130, and an anode 150 formed on the second flow channel 140.

[0041] The alkaline water electrolysis device according to one embodiment of the present invention is an ultra-low power cation exchange membrane alkaline water electrolysis device that uses an oxidation reaction of metal powder particles to overcome the limitations of existing technologies. This electrolysis technology produces hydrogen gas by inducing an oxidation reaction of metal powder particles into metal ions in the second flow channel 140 on the anode 150 side and causing a water splitting reaction in the first flow channel 120 on the cathode 110 side.

[0042] In this case, the operating voltage of the alkaline water electrolysis device in actual use can be reduced by the standard reduction potential of the spontaneously oxidized metal powder. Therefore, alkaline water electrolysis devices using the oxidation reaction of metal powder can produce hydrogen with much less power than existing methods, and can also create additional value by producing high-value-added metal oxides (e.g., zinc oxide) that can be used in a variety of industries.

[0043] Furthermore, the alkaline water electrolysis apparatus according to an embodiment of the present invention can further improve safety by replacing the oxygen evolution reaction, which requires an expensive catalyst and causes the risk of hydrogen-oxygen mixture explosion, with a metal oxidation reaction.

[0044] Each component will be described in more detail below.

[0045] First, an alkaline water electrolysis apparatus according to an embodiment of the present invention includes a cathode 110 .

[0046] The cathode 110 may include at least one of gold (Au), silver (Ag), platinum (Pt), iridium (Ir), titanium (Ti), ruthenium (Ru), copper (Cu), a Ti-Ru / Ir mesh coated with a titanium (Ti)-ruthenium (Ru) alloy, a platinum (Pt) mesh, a titanium-ruthenium alloy Ti / Ru, indium tin oxide (ITO), stainless steel, and graphite (carbon or graphite fiber).

[0047] The alkaline water electrolysis apparatus according to an embodiment of the present invention includes a first flow channel 120 formed on a cathode 110 .

[0048] The first flow channel 120 can contain a catholyte.

[0049] The catholyte may include at least one of potassium ferricyanide (K3Fe(CN)6), sodium chloride (NaCl), sodium sulfate (Na2SO4), hydrochloric acid (HCl), sodium sulfate (Na2SO4), iron (III) chloride (FeCl3), sodium chloride (NaCl), potassium hydroxide (KOH), ammonium bicarbonate (NH4HCO3), potassium carbonate (K2CO3), sodium hydroxide (NaOH), sodium carbonate (Na2CO3), and ultrapure water.

[0050] The catholyte may be in the form of a solution.

[0051] The alkaline water electrolysis apparatus according to an embodiment of the present invention includes a cation exchange membrane (CEM) 130 formed on a first flow channel 120 .

[0052] The cation exchange membrane 130 is a synthetic resin membrane that selectively allows cations to pass through. The cation exchange membrane 130 is negatively charged, which makes it difficult for anions to pass through due to repulsion, and allows only cations to pass through.

[0053] Therefore, the alkaline water electrolysis apparatus according to an embodiment of the present invention includes a cation exchange membrane 130, which can selectively allow metal ions (cations) contained in the second flow channel 140 to permeate into the first flow channel 120. Therefore, in the alkaline water electrolysis apparatus according to an embodiment of the present invention, the metal ions (cations) can be used as charge-transfer ions.

[0054] The cation exchange membrane 130 may include an organic membrane, and preferably may include at least one of polystyrene, polyimide, polyester, polyether, polyethylene, polytetrafluoroethylene, polymethylammonium chloride, and polyglycidyl methacrylate, but is not limited thereto.

[0055] The alkaline water electrolysis apparatus according to one embodiment of the present invention includes a second flow channel 140 formed on the cation exchange membrane 130 .

[0056] The second flow channel 140 contains metal powder and can be used as a metal powder fluid electrode.

[0057] The electrodes (at least one of the anode and cathode) used in the alkaline water electrolysis device according to an embodiment of the present invention are electrodes where oxidation reactions occur, and if a material with redox potential is used as a typical solid electrode, there may be a problem in that the electrode is worn out due to continuous oxidation reactions. The worn-out electrode (at least one of the anode and cathode) needs to be replaced, which hinders continuous water electrolysis operation.

[0058] However, in an alkaline water electrolysis apparatus according to an embodiment of the present invention, unlike conventional electrodes that do not require electrode replacement during system operation, the use of a metal powder fluid electrode allows the powder to be injected into the flow channel (at least one of the first flow channel and the second flow channel) together with the electrolyte during system operation, and can be consumed while undergoing an oxidation reaction in place of the electrodes within the flow channel.

[0059] Therefore, by replacing the electrode having a redox potential with a powder containing a material equivalent to the electrode, the phenomenon of electrode (i.e., at least one of the anode and cathode) being consumed can be overcome, enabling continuous water electrolysis.

[0060] In addition, the metal powder can be injected into the cell through the flow channel (at least one of the first flow channel and the second flow channel) while mixed with the electrolyte, and spreads uniformly within the flow channel (at least one of the first flow channel and the second flow channel). Each metal powder can serve as an electrode (at least one of the anode and the cathode). This solves the problem of increased maintenance and repair costs due to the wear and replacement of electrodes (at least one of the anode and the cathode). It also contributes to improving the efficiency of the system and the water electrolysis capacity by increasing the effective area where the oxidation reaction occurs.

[0061] In addition, in order to obtain a power reduction effect by utilizing a battery that uses the oxidation potential of the metal anode 150 for water electrolysis, an alkaline water electrolysis apparatus according to an embodiment of the present invention can continuously supply the anode 150 material using a metal powder fluid electrode.

[0062] Therefore, when a voltage is applied perpendicularly to the cation exchange membrane 130, the metal powder particles are oxidized in the second flow channel 140 to generate metal ions, and the potential difference of the alkaline water electrolysis device can be adjusted at the same time.

[0063] Specifically, in an alkaline water electrolysis apparatus according to one embodiment of the present invention, the hydrogen generation channel (first flow channel 120) and the metal powder fluid electrode (second flow channel 140) are separated by a cation exchange membrane 130 having ion selectivity. Therefore, when the metal powder in the second flow channel 140 on the anode 150 side is oxidized to metal ions, it has a standard reduction potential of -0.76 V. This reaction can be used to reduce the potential difference required for electrolysis, resulting in a gain in hydrogen production costs.

[0064] Therefore, by replacing the reaction occurring on the anode 150 side with a metal oxidation reaction rather than an oxygen evolution reaction, it is not necessary to use an expensive catalyst required for the oxygen evolution reaction, and the risk of a hydrogen-oxygen mixed gas explosion due to oxygen evolution can be eliminated.

[0065] In addition, metal ions generated in the second flow channel 140 on the anode 150 side and hydroxide ions generated in the first flow channel 120 on the cathode 110 side move through a cation exchange membrane during the water electrolysis process and are synthesized into at least one of a metal hydroxide and a metal oxide, thereby making it possible to recover a large portion of the hydrogen production costs through metal oxide (e.g., zinc oxide), which is a high-value-added product that is more expensive than metals (e.g., zinc).

[0066] The potential difference required for electrolysis in an alkaline water electrolysis device according to an embodiment of the present invention may be within −0.36 V (lower heating value), and if the potential difference is less than −0.36 V, a problem may occur in which water decomposition does not occur.

[0067] The metal powder may include at least one of zinc (Zn), lead (Pb), cadmium (Cd), iron (Fe), magnesium (Mg), and aluminum (Al), and preferably includes zinc (Zn). Zinc has a high oxidation potential of +0.76 V and is inexpensive compared to other metals and has the advantages of being non-flammable.

[0068] For example, an alkaline water electrolysis apparatus according to an embodiment of the present invention uses a cation exchange membrane 130 as a separation membrane and zinc ions as charge-transfer ions, whereby zinc ions oxidized in a second flow channel (e.g., zinc powder flow channel) on the anode 150 side can move to the cathode 110 side through the cation exchange membrane 130 and encounter hydroxide ions generated through a hydrogen generation reaction on the cathode 110 side, thereby producing zinc oxide.

[0069] Furthermore, when hydroxide ions are used as charge transfer ions, there is a possibility that zinc oxide may be generated by surrounding the zinc powder particles to form a film, thereby preventing the oxidation reaction of zinc, or that the product zinc oxide may need to be separated from the zinc powder particles. However, an alkaline water electrolysis apparatus according to one embodiment of the present invention uses zinc powder particles, which are metal powder particles, as charge transfer ions, and thereby moves the zinc oxide generation channel toward the cathode 110, and as zinc oxide is generated, it forms a film by surrounding the zinc powder particles to prevent the oxidation reaction of zinc, or it is possible to eliminate the work of separating the product zinc oxide from the zinc powder particles.

[0070] Furthermore, in an alkaline water electrolysis apparatus according to an embodiment of the present invention, the electron transfer ability may be adjusted depending on the concentration of metal powder particles contained in the second flow channel 140. Specifically, as the concentration of metal powder particles contained in the second flow channel 140 increases, electrons may be more effectively transferred from the electrodes to the metal powder particles, thereby increasing the efficiency of the target redox reaction.

[0071] For example, the concentration of the metal powder contained in the second flow channel 140 may be 1 wt% to 20 wt%. If the concentration of the metal powder is less than 1 wt%, there is a problem that the metal powder and the electrodes may come into discontinuous contact, and if the concentration of the metal powder is more than 20 wt%, there is a problem that the metal powder does not flow in the second flow channel 140.

[0072] By way of example, the metal particulates may be metal nanoparticles.

[0073] The second flow channel 140 can also contain an anolyte.

[0074] The anolyte may include at least one of sodium acetate (CH3COONa) + phosphate, phosphate-buffered saline (PBS), ammonium chloride (NH4Cl), monosodium phosphate (NaH2PO4), potassium ferrocyanide (K4Fe(CN)6), sodium sulfate (Na2SO4), ammonium bicarbonate (NH4HCO3), sodium hydroxide (NaOH), sodium chloride (NaCl), iron(II) chloride (FeCl2), sulfuric acid (H2SO4), sodium chloride (NaCl), and potassium hydroxide (KOH), but is not limited thereto.

[0075] The anolyte may be in the form of a solution.

[0076] The alkaline water electrolysis apparatus according to one embodiment of the present invention includes an anode 150 formed on the second flow channel 140 .

[0077] The anode 150 may include at least one of gold (Au), silver (Ag), platinum (Pt), iridium (Ir), aluminum (Al), titanium (Ti), ruthenium (Ru), a Ti-Ru / Ir mesh coated with a titanium (Ti)-ruthenium (Ru) alloy, a platinum (Pt) mesh, a titanium-ruthenium alloy (Ti / Ru), and indium tin oxide (ITO).The anode 150 may also include at least one of chromium (Cr), nickel (Ni), and molybdenum (Mo) used in titanium V4A steel, and chromium (Cr) and iron (Fe) used in stainless steel.

[0078] The mechanism of water electrolysis using an alkaline water electrolysis apparatus according to an embodiment of the present invention will be described below. First, when a voltage is applied in a direction perpendicular to the cation exchange membrane 130, the metal powder particles are oxidized in the second flow channel 140 to generate metal ions. At the same time, the potential difference of the alkaline water electrolysis apparatus can be adjusted using the standard reduction potential of the metal powder particles.

[0079] The metal ions generated in the second flow channel 140 can then move to the first flow channel 120 along the direction of the electric field, while at the same time, water is decomposed into hydrogen and hydroxide ions in the first flow channel 120, and the generated hydroxide ions can react with the metal ions to generate at least one of a metal hydroxide and a metal oxide.

[0080] At this time, the alkaline water electrolysis apparatus according to an embodiment of the present invention can convert metal hydroxide into metal oxide in the first flow channel 120 by adjusting the operating temperature.

[0081] The operating temperature may be 20° C. to 100° C. If the operating temperature is lower than 20° C., the Gibbs free energy required for water splitting increases, resulting in a higher minimum voltage requirement. If the operating temperature is higher than 100° C., the ionic conductivity increases, improving water electrolysis performance, but additional thermal energy is required to increase the temperature. In addition, water, which is a liquid electrolyte, evaporates within the water electrolysis device, damaging the ion exchange membrane within the device due to heat, thereby shortening its lifespan.

[0082] For example, when zinc powder is used as the metal powder, an alkaline water electrolysis apparatus according to an embodiment of the present invention is an alkaline water electrolysis apparatus based on a zinc oxidation reaction, and may include an anode 150 where zinc is oxidized, a cathode 110 where hydrogen is generated, and a cation exchange membrane 130 that physically separates the two electrodes and the electrolyte.

[0083] At this time, when a voltage is applied perpendicular to the cation exchange membrane 130, zinc is spontaneously oxidized on the anode 150 side, reducing the potential difference required for water decomposition by the standard reduction potential of the reaction. The zinc ions pass through the cation exchange membrane 130 and move to the cathode 110 side. At the same time, hydrogen is generated on the cathode 110 side as water is decomposed into hydrogen and hydroxide ions. The generated hydroxide ions can be synthesized into zinc oxide by meeting with zinc ions.

[0084] At this time, the reaction of water in the first flow channel 120 is as shown in the following Equation 1, and the reaction of zinc powder particles in the second flow channel 140 is as shown in the following Equation 2.

[0085] H2O+2e-→H2↑+2OH - (E0=-0.83V vs. SHE) (Equation 1) Zn → Zn 2+ +2e - (E0=0.76V vs.SHE) (Formula 2)

[0086] In addition, by adjusting the temperature within the operating temperature range, the product can be converted from zinc hydroxide to zinc oxide particles (e.g., zinc oxide nanoparticles). The resulting zinc oxide is an advanced material used in the rubber, ceramic, pharmaceutical, and cosmetic industries, and is a high-value-added product that is more expensive than zinc.

[0087] Therefore, in an alkaline water electrolysis apparatus according to an embodiment of the present invention, an electrode material is added to the second flow channel 140, and the electrodes are configured to flow through the second flow channel 140. This reduces the voltage required for operation by using chemical energy released by the oxidation of zinc, and simultaneously transports zinc ions through the cation exchange membrane 130 to synthesize zinc hydroxide / zinc oxide in the catholyte.

[0088] According to an embodiment, the alkaline water electrolysis apparatus according to the present invention may further include a cationic polymer electrolyte layer 160 at the interface between the cathode 110 and the first flow channel 120 .

[0089] Specifically, by adding a cationic polymer electrolyte layer 160 to the hydrogen generation channel on the cathode 110 side, the cationic polymer electrolyte, which has a positive charge (+), has the property of moving in the direction of the electric field and is therefore pulled toward the cathode 110, forming a membrane made of the polymer electrolyte on the surface of the cathode 110.

[0090] The formed cationic polymer electrolyte layer 160 is positively charged, and therefore repels cations and allows anions to pass through due to its electrostatic properties. This prevents zinc ions that pass through the cation exchange membrane 130 and enter the first flow channel 120 on the cathode 110 side from being reduced on the cathode 110 to form metal dendrite, and allows hydroxide ions generated during the hydrogen generation reaction to pass through, separating the hydrogen generation portion from the zinc oxide synthesis portion.

[0091] Furthermore, the polymer electrolyte (preferably, a polymer electrolyte aqueous solution) exists in the form of charged polymer chains in the aqueous solution and therefore contains a large amount of water, which poses no problem in supplying the water necessary for the hydrogen generation reaction. Furthermore, since the polymer electrolyte is a charged polymer, it can also have the effect of increasing the conductivity of the electrolyte, i.e., reducing the resistance.

[0092] The cationic polyelectrolyte layer 160 is used as a cathode electrolyte to control the reaction by separating the produced hydrogen from zinc hydroxide / zinc oxide. The cationic polyelectrolyte is positively charged, and when a voltage is applied, it migrates toward the cathode due to the generated electric field and is adsorbed to the electrode. In this way, the cationic polyelectrolyte surrounding the cathode 110 can suppress the formation of dendrites by preventing the migration of zinc ions in the first flow channel 120 toward the cathode 110.

[0093] The cationic polyelectrolyte layer 160 may further include at least one of PQ-10, protonated polyethyleneimine (PEI), protonated poly(allylamine) (PAH), and polydiallyldimethylammonium chloride (PDADMAC).

[0094] An ultra-low power alkaline water electrolysis device using a metal oxidation reaction (e.g., zinc oxidation reaction) according to an embodiment of the present invention can be used not only for water electrolysis but also for fuel cells, thereby improving performance and increasing energy efficiency, and thus making it possible to meet the growing demand for hydrogen.

[0095] In addition, it is not limited to simply improving the performance / energy efficiency of alkaline water electrolysis equipment, but also provides cost advantages in line with the growing zinc oxide market through the high-value-added zinc oxide synthesized as the process progresses.

[0096] FIG. 3 is a schematic diagram showing an alkaline water electrolysis apparatus with a zero gap structure according to an embodiment of the present invention.

[0097] The zero-gap alkaline water electrolysis apparatus according to an embodiment of the present invention includes a first flow channel 120, a cathode 110 formed on the first flow channel 120, a cation exchange membrane 130 formed on the cathode 110, an anode 150 formed on the cation exchange membrane 130, and a second flow channel 140 formed on the anode 150, wherein the second flow channel 140 contains metal powder and is used as a metal powder fluid electrode.

[0098] Liquid electrolytes have a relatively large resistance to ion migration compared to solid polymer ion exchange membranes. The longer the liquid electrolyte channel in the direction of the ion migration path, the greater the resistance, and the shorter the liquid electrolyte channel, the smaller the resistance. To minimize resistance, the zero-gap structure excludes the liquid electrolyte channel from the ion migration path.

[0099] Therefore, the zero-gap alkaline water electrolysis apparatus according to an embodiment of the present invention has a configuration in which the anode 150 and the cation exchange membrane 130 are attached to each other, thereby excluding the first flow channel 120 and the second flow channel 140, which have high resistance between the anode 150 and the cathode 110 and the cation exchange membrane 130, from the zinc ion transport path, and is located outside the anode and cathode, thereby minimizing the resistance between the anode 150 and the cathode 110.

[0100] As a result, in the zero-gap structure, even when the same voltage is applied, resistance acts small, allowing a high current to flow, and the amount of hydrogen generated increases in proportion to the current value. Furthermore, while hydrogen bubbles generated in the liquid electrolyte between the anode 150 and the cathode 110 in Figure 1 can act as resistance in the water electrolysis device, in the case of Figure 3, hydrogen bubbles are generated outside the zinc ion migration path rather than within the zinc ion migration path from the anode to the cathode, which solves the problem of increased electrical resistance due to bubbles during the hydrogen production process and similarly achieves the effect of increasing the amount of hydrogen generated.

[0101] FIG. 4 is a schematic diagram showing an alkaline water electrolysis apparatus according to another embodiment of the present invention.

[0102] The alkaline water electrolysis apparatus according to the other embodiment of the present invention may include the same components as the alkaline water electrolysis apparatus according to the other embodiment of the present invention, except that hydroxide ions are used as charge-transfer ions due to the use of the anion exchange membrane 230. Therefore, a description of the same components will be omitted.

[0103] An alkaline water electrolysis apparatus according to another embodiment of the present invention includes a cathode 210, a first flow channel 220 formed on the cathode 210, an anion exchange membrane (AEM, anion polyelectrolyte) 230 formed on the first flow channel 220, a second flow channel 240 formed on the anion exchange membrane 230, and an anode 250 formed on the second flow channel 240, wherein the second flow channel 240 contains metal powder and is used as a metal powder fluid electrode.

[0104] The alkaline water electrolysis apparatus according to another embodiment of the present invention includes an anion exchange membrane 230 formed on the first flow channel 220 .

[0105] The anion exchange membrane 230 is a synthetic resin membrane that selectively allows anions to pass through, and is positively charged, so that cations are repelled and have difficulty passing through, and only anions can pass through.

[0106] Therefore, the alkaline water electrolysis apparatus according to another embodiment of the present invention includes an anion exchange membrane 230, which can selectively allow hydroxide ions (anions) contained in the first flow channel 220 to permeate the second flow channel 240. Therefore, in the alkaline water electrolysis apparatus according to another embodiment of the present invention, hydroxide ions (anions) can be used as charge-transfer ions.

[0107] The anion exchange membrane 230 may include at least one of Fumasep FAA3 from Fumatech, A201 from Tokuyama, AEMION from Ionomr, Sustainion from Dioxide Material, Durion TM1 from Orion Polymer, AMHPP from Ralex, and AMHPES from Ralex.

[0108] In the alkaline water electrolysis device according to another embodiment of the present invention, when a voltage is applied in a direction perpendicular to the anion exchange membrane 230, the metal powder particles are oxidized in the second flow channel 240 to generate metal ions, and the potential difference of the alkaline water electrolysis device can be adjusted at the same time.

[0109] At the same time, water is decomposed into hydrogen and hydroxide ions in the first flow channel 220, and the generated hydroxide ions can move to the second flow channel 240 along the direction of the electric field.

[0110] Therefore, in the second flow channel 240, the hydroxide ions can react with the metal ions to generate at least one of a metal hydroxide and a metal oxide.

[0111] In this case, the alkaline water electrolysis apparatus according to another embodiment of the present invention can convert metal hydroxide into metal oxide in the second flow channel 240 by adjusting the operating temperature.

[0112] The operating temperature may be 20° C. to 100° C. If the operating temperature is lower than 20° C., the Gibbs free energy required for water splitting increases, resulting in a higher minimum voltage requirement. If the operating temperature is higher than 100° C., the ionic conductivity increases, improving water electrolysis performance, but additional thermal energy is required to increase the temperature. In addition, water, which is a liquid electrolyte, evaporates within the water electrolysis device, damaging the ion exchange membrane within the device due to heat, thereby shortening its lifespan.

[0113] Unlike the alkaline water electrolysis device according to one embodiment of the present invention, the alkaline water electrolysis device according to another embodiment of the present invention uses hydroxide ions as charge carrier ions. These hydroxide ions have much higher ion mobility than zinc ions, which are the charge carrier ions in the alkaline water electrolysis device according to one embodiment of the present invention. Furthermore, the ion migration resistance of the first flow channel 220, the second flow channel 240, and the anion exchange membrane 230 is much lower. Therefore, when the same voltage is applied, the current value is larger, which can increase the amount of hydrogen generated.

[0114] According to an embodiment, the alkaline water electrolysis apparatus according to another embodiment of the present invention may further include an anionic polymer electrolyte layer 260 at the interface between the second flow channel 240 and the anode 250 .

[0115] In an alkaline water electrolysis apparatus according to another embodiment of the present invention, when an anion exchange membrane 230 is used and hydroxide ions are used as charge-transfer ions, an anionic polymer electrolyte layer 260 is formed using an anionic polymer electrolyte aqueous solution that migrates toward the anode 250 by an electric field to prevent precipitation from forming at the anode 250, thereby preventing fouling at the electrode.

[0116] [Production Example 1]: Alkaline water electrolysis apparatus according to one embodiment of the present invention (FIG. 1) The device consisted of an anode (carbon); a second flow channel (0.5M ZnSO4) containing zinc powder; a cation exchange membrane; a first flow channel (0.5M NaOH); and a cathode (carbon). Electrolyte was injected into both the first and second flow channels at a flow rate of 10 μL / min, and a voltage of 2 V was applied to observe bubble generation. Open circuit voltage (OCV) refers to the voltage measured at 0 A current before applying voltage for the bubble generation experiment. It indicates the degree of voltage gain from the zinc oxidation reaction when voltage is immediately applied.

[0117] [Production Example 2]: Alkaline water electrolysis device according to one embodiment of the present invention including a cationic polymer electrolyte layer (FIG. 2) The device consisted of an anode (carbon); a second flow channel containing zinc powder (0.5M ZnSO4); a cation exchange membrane; a first flow channel containing a cationic polymer electrolyte (0.5M NaOH + cationic polyelectrolyte); and a cathode (carbon). The cationic solid polymer electrolyte used was 1 wt% polyquaternium-10 (PQ-10). The electrolyte was injected into both the first and second flow channels at a flow rate of 10 μL / min, and bubble generation was observed when a voltage of 2 V was applied. Open circuit voltage (OCV) refers to the voltage measured at 0 A current before applying voltage for the bubble generation experiment. This indicates the degree of voltage gain from the zinc oxidation reaction when voltage is immediately applied.

[0118] [Production Example 3]: Alkaline water electrolysis device with zero gap structure according to an embodiment of the present invention (FIG. 3) The fabrication was the same as in Preparation Example 1, except that it included a second flow channel, an anode (carbon), a cation exchange membrane, a cathode (carbon), and a first flow channel.

[0119] FIG. 5 is a microscope image showing an alkaline water electrolysis apparatus in accordance with an embodiment of the present invention, and FIG. 6 is a graph showing measurement results of the open circuit voltage of the alkaline water electrolysis apparatus in accordance with an embodiment of the present invention.

[0120] Referring to FIG. 5, it can be seen that 0.5M NaOH was used in the first flow channel and hydrogen bubbles were generated in the cathode side channel.

[0121] Furthermore, referring to FIG. 6, it can be seen that the alkaline water electrolysis apparatus according to an embodiment of the present invention achieves a voltage gain of 0.651 V during operation.

[0122] FIG. 7 is a microscopic image of an alkaline water electrolysis device including a cationic polymer electrolyte layer in accordance with an embodiment of the present invention, and FIG. 8 is a graph showing measurement results of the open circuit voltage of an alkaline water electrolysis device including a cationic polymer electrolyte layer in accordance with an embodiment of the present invention.

[0123] Referring to FIG. 7, 0.5 M NaOH and 1 wt % of the cationic polymer electrolyte pq-10 were used in the first flow channel, and hydrogen bubbles were generated in the cathode channel.

[0124] Referring to FIG. 8, it can be seen that an alkaline water electrolysis device including a cationic polymer electrolyte layer according to an embodiment of the present invention can obtain a voltage gain of 0.64 V during operation.

[0125] FIG. 9 is a microscope image showing a first flow channel including a cationic polymer electrolyte layer in an alkaline water electrolysis apparatus including a cationic polymer electrolyte layer according to one embodiment of the present invention.

[0126] Referring to Figure 9, it can be seen that in the zinc-zinc symmetrical structure device, the cationic polymer electrolyte (PQ-10) layer formed on the cathode side prevents zinc ions from migrating to the cathode and being reduced, and only the hydrogen generation reaction occurs.

[0127] FIG. 10 is a microscope image showing an alkaline water electrolysis apparatus having a zero gap structure according to an embodiment of the present invention.

[0128] Referring to FIG. 10, it can be seen that the alkaline water electrolysis device having the zero gap structure according to the embodiment of the present invention is well manufactured.

[0129] Meanwhile, the embodiments of the present invention disclosed in this specification and the drawings are merely specific examples presented to facilitate understanding and are not intended to limit the scope of the present invention. It will be obvious to those skilled in the art to which the present invention pertains that other modifications based on the technical concept of the present invention can be implemented in addition to the embodiments disclosed herein.

Claims

1. cathode; a first flow channel formed on the cathode; a cation exchange membrane (CEM) formed on the first flow channel; a second flow channel formed on the cation exchange membrane; and an anode formed on the second flow channel; Including, The alkaline water electrolysis apparatus, wherein the second flow channel contains metal powder and is used as a metal powder fluid electrode.

2. 2. The alkaline water electrolysis device according to claim 1, wherein when a voltage is applied in a direction perpendicular to the cation exchange membrane, the metal powder is oxidized in the second flow channel to generate metal ions, and a standard reduction potential of the metal powder is used to adjust the potential difference of the alkaline water electrolysis device.

3. The alkaline water electrolysis apparatus according to claim 2, wherein the metal ions generated in the second flow channel move to the first flow channel in the direction of the electric field.

4. 4. The alkaline water electrolysis apparatus of claim 3, wherein water is decomposed into hydrogen and hydroxide ions in the first flow channel, and the generated hydroxide ions react with the metal ions to generate at least one of a metal hydroxide and a metal oxide.

5. The alkaline water electrolysis apparatus according to claim 4, wherein the operating temperature is adjusted to convert the metal hydroxide into the metal oxide in the first flow channel.

6. The alkaline water electrolysis apparatus according to claim 5, wherein the operating temperature is 20°C to 100°C.

7. 2. The alkaline water electrolysis apparatus according to claim 1, wherein the metal powder contains at least one of zinc (Zn), lead (Pb), cadmium (Cd), iron (Fe), magnesium (Mg), and aluminum (Al).

8. The alkaline water electrolysis device according to claim 1, further comprising a cationic polymer electrolyte layer at an interface between the cathode and the first flow channel.

9. a first flow channel; a cathode formed over the first flow channel; a cation exchange membrane formed on the cathode; an anode formed on the cation exchange membrane; and a second flow channel formed on the anode; Including, The alkaline water electrolysis device having a zero-gap structure, wherein the second flow channel contains metal powder and is used as a metal powder fluid electrode.

10. cathode; a first flow channel formed on the cathode; an anion exchange membrane (AEM, Anion Polyelectrolyte) formed on the first flow channel; a second flow channel formed on the anion exchange membrane; and an anode formed on the second flow channel; Including, The alkaline water electrolysis apparatus, wherein the second flow channel contains metal powder and is used as a metal powder fluid electrode.

11. 11. The alkaline water electrolysis device according to claim 10, wherein when a voltage is applied in a direction perpendicular to the anion exchange membrane, the metal powder is oxidized in the second flow channel to generate metal ions, and a standard reduction potential of the metal powder is used to adjust the potential difference of the alkaline water electrolysis device.

12. 12. The alkaline water electrolysis apparatus of claim 11, wherein water is decomposed into hydrogen and hydroxide ions in the first flow channel, and the generated hydroxide ions move to the second flow channel in a direction of an electric field.

13. 13. The alkaline water electrolysis apparatus of claim 12, wherein the hydroxide ions react with the metal ions in the second flow channel to produce at least one of a metal hydroxide and a metal oxide.

14. The alkaline water electrolysis apparatus according to claim 13, wherein the operating temperature is adjusted to convert the metal hydroxide into the metal oxide in the second flow channel.

15. The alkaline water electrolysis apparatus according to claim 14, wherein the operating temperature is 20°C to 100°C.

16. The alkaline water electrolysis device according to claim 10, further comprising an anionic polymer electrolyte layer at an interface between the second flow channel and the anode.

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