RECHARGEABLE METAL BATTERY

Abstract

A rechargeable metal battery with improved efficiency and a system for generating hydrogen and storing carbon dioxide equipped with this battery. A metal battery according to one embodiment comprises an electrode unit comprising a metal electrode, a discharge unit arranged on a first side of the electrode unit, a charging unit arranged on a second side of the electrode unit, a first ion exchange membrane arranged between the electrode unit and the discharge unit, and a second ion exchange membrane arranged between the electrode unit and the charging unit.

Description

BACKGROUND OF REVELATION 1. Area of ​​Revelation

[0001] The present disclosure relates to a rechargeable metal battery with improved efficiency and a hydrogen production and carbon dioxide storage system equipped with the same battery. 2. Description of the state of the art

[0002] Conventional metal batteries can cause problems due to their structure, in which a single electrode acts as both an oxidation electrode and a reduction electrode.

[0003] Oxygen generated during battery charging corrodes the carbon support supporting the active metal, thereby degrading the battery's performance and durability. Furthermore, since the material of the oxidation electrode and the reduction electrode must be present together, the electrode structure is complicated, and the battery may not adequately deliver its rated power due to the occurrence of overvoltage during battery operation.

[0004] Since oxygen and hydrogen occur in the same space, there is also a risk that the two gases will mix and cause ignition, explosion, etc. SUMMARY OF REVELATION

[0005] In one aspect, the present disclosure provides a reliably functioning, rechargeable metal battery.

[0006] In another aspect, the present disclosure provides a rechargeable metal battery with improved efficiency.

[0007] The objects of the present disclosure are not limited to those described above. The above and other objects of the present disclosure will become apparent from the following description and will be realized by the means and combinations of means recited in the claims.

[0008] In order to solve the above-mentioned problems encountered in the related art, the present disclosure discloses a method for manufacturing a perovskite solar cell module encapsulated with a self-cleaning thin film and a perovskite solar cell module having a self-cleaning function manufactured by the method.

[0009] A metal battery according to an embodiment of the present disclosure includes an electrode unit comprising a metal electrode, a discharge unit disposed on a first side of the electrode unit, a charging unit disposed on a second side of the electrode unit, a first ion exchange membrane disposed between the electrode unit and the discharge unit, and a second ion exchange membrane disposed between the electrode unit and the charging unit. The discharge unit may include a first space having a predetermined size, a first electrolyte accommodated in the first space, and a reduction electrode at least partially immersed in the first electrolyte.The charging unit may include a second space having a predetermined size, a second electrolyte accommodated in the second space, and an oxidation electrode at least partially immersed in the second electrolyte. The electrode unit may include a third space having a predetermined size, a third electrolyte accommodated in the third space, and the metal electrode at least partially immersed in the third electrolyte.

[0010] The metal electrode may comprise at least one selected from the group consisting of zinc (Zn), aluminum (Al), and combinations thereof.

[0011] The reduction electrode may comprise a support and a catalytic metal loaded on the support.

[0012] The oxidation electrode may comprise a nickel foam.

[0013] The discharge unit may further include a first body plate having a plate shape, a reducing electrode current collector disposed on a first surface of the first body plate and having a sheet shape, and a first spacer having a frame shape disposed between the reducing electrode current collector and the first ion exchange membrane to define the first space. The reducing electrode may be disposed on the first surface of the reducing electrode current collector.

[0014] The first spacer may comprise a first electrolyte inlet formed to extend through a first portion of a flank of the first spacer and configured to enable communication between the first space and an external environment, and a first electrolyte outlet formed to extend through a second portion of the flank of the first spacer and configured to enable communication between the first space and the external environment, the second portion being spaced apart from the first portion.

[0015] The charging unit may further include a second body plate having a plate shape, an oxidation electrode current collector disposed on a first surface of the second body plate and having a sheet shape, and a second spacer having a frame shape disposed between the oxidation electrode current collector and the second ion exchange membrane to define the second space. The oxidation electrode may be disposed on the first surface of the oxidation electrode current collector.

[0016] The second spacer may comprise: a second electrolyte inlet formed to extend through a first portion of a flank of the second spacer and configured to enable communication between the second space and the external environment, and a second electrolyte outlet formed to extend through a second portion of the flank of the second spacer and configured to enable communication between the second space and the external environment, wherein the first portion is spaced from the second portion.

[0017] The electrode unit may further include an electrode current collector having a sheet shape, a third spacer disposed between the metal electrode current collector and the first ion exchange membrane, and a fourth spacer disposed between the metal electrode current collector and the second ion exchange membrane. The third spacer and the fourth spacer form the third space, and the metal electrode may be disposed on both surfaces of the metal electrode current collector.

[0018] The third space and the fourth spacer may each comprise a third electrolyte inlet formed to extend through a first portion of a flank of the spacer and configured to enable communication between the third space and the external environment; and a third electrolyte outlet formed to extend through a second portion of the flank of the spacer and configured to enable communication between the third space and the external environment, wherein the first portion is spaced from the second portion.

[0019] The first space and the third space may be separated by the first ion exchange membrane, and the second space and the third space may be separated by the second ion exchange membrane.

[0020] The first ion exchange membrane may comprise a cation exchange membrane, and the second ion exchange membrane may comprise a cation exchange membrane.

[0021] The first ion exchange membrane may comprise a cation exchange membrane, and the second ion exchange membrane may comprise an anion exchange membrane.

[0022] The first electrolyte may include water and bicarbonate.

[0023] The second electrolyte may comprise at least one selected from the group consisting of potassium hydroxide (KOH), sodium hydroxide (NaOH), and combinations thereof.

[0024] The third electrolyte may comprise at least one selected from the group consisting of potassium hydroxide (KOH), sodium hydroxide (NaOH), and combinations thereof.

[0025] The metal battery may be configured such that, upon discharging, a reaction represented by the following reaction formula 1 occurs at the electrode unit, and a reaction represented by the following reaction formula 2 occurs at the discharge unit. M(s) + aOH - (aq) -> M(OH)a b- (aq) + (ab)e - Reaction formula 1:

[0026] In reaction formula 1, M may comprise at least one selected from the group consisting of lithium (Li), sodium (Na), magnesium (Mg), zinc (Zn), aluminum (Al), and combinations thereof.

[0027] Where a can be an integer in the range 1 to 5.

[0028] Where b can be a value (a - oxidation number of M) obtained by subtracting an oxidation number of M from a. 2H + (aq) + 2e - → H 2 (g) Reaction formula 2:

[0029] The metal battery may be configured such that, upon charging, a reaction represented by the following reaction formula 3 occurs at the electrode unit, and a reaction represented by the following reaction formula 4 occurs at the charging unit. M(OH)a b- (aq) + (ab)e - -> M(s) + aOH - (aq) Reaction formula 3:

[0030] In reaction formula 3, M may comprise at least one selected from the group consisting of lithium (Li), sodium (Na), magnesium (Mg), zinc (Zn), aluminum (Al), and combinations thereof.

[0031] Where a can be an integer in the range 1 to 5.

[0032] Where b can be a value (a - oxidation number of M) obtained by subtracting an oxidation number of M from a. 40H - (aq) → O 2 (g) + 2H 2 O(l) + 4e - Reaction formula 4:

[0033] In another aspect of the present disclosure, a system for generating hydrogen and storing carbon dioxide is provided, comprising a metal battery, a first electrolyte circulation unit connected to the metal battery and configured to receive the first electrolyte discharged from the discharge unit, separate the hydrogen contained in the first electrolyte, and supply the first electrolyte to the discharge unit, a second electrolyte circulation unit connected to the metal battery and configured to receive the second electrolyte discharged from the charge unit, separate the oxygen contained in the second electrolyte, and supply the second electrolyte to the charge unit, and a third electrolyte circulation unit connected to the metal battery and configuredto receive the third electrolyte discharged from the electrode unit and to supply the third electrolyte to the electrode unit.

[0034] According to the present disclosure, it is possible to obtain a reliably functioning, rechargeable metal battery.

[0035] According to the present disclosure, it is possible to obtain a rechargeable metal battery with improved efficiency.

[0036] The advantages of the present disclosure are not limited to those described above. It should be understood that the advantages of the present disclosure include all effects that can be derived from the following description. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a metal battery according to the prior art; Fig. 2 shows a system for generating hydrogen and storing carbon dioxide according to a first embodiment of the present disclosure; Fig. 3 shows a system for generating hydrogen and storing carbon dioxide according to a second embodiment of the present disclosure; Fig. 4 shows a metal battery according to an embodiment of the present disclosure; Fig. 5A shows a first spacer; Fig. 5B shows a second spacer; Fig. 5C shows a third spacer; Fig. 5D shows a fourth spacer; Fig. 6 shows a result of a comparison between the performance of a metal battery of Example 1 and the performance of a metal battery of a comparative example; and Fig. Figure 7 shows measurements of the performance of a metal battery from Example 2. DETAILED DESCRIPTION

[0037] The above objects, other objects, features, and advantages of the present disclosure will become readily apparent from the following preferred embodiments taken in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments described herein and may be embodied in other forms. The embodiments described herein are provided so that this disclosure will be thorough and complete, and so that the spirit of the present disclosure will fully convey to those skilled in the art.

[0038] In the drawings, like elements are identified by like reference numerals. In the accompanying drawings, the dimensions of the structures are larger than their actual sizes for clarity of the present disclosure. As used in the description, the terms "first," "second," etc., may be used to describe various components, but the components are not to be construed as limited to these terms. These terms are used only to distinguish one component from another component. For example, without departing from the scope of the present disclosure, a first component may be referred to as a second component, and a second component may also be referred to as a first component. As used herein, the singular forms "a," "an," and "the" include the plural forms unless the context clearly indicates otherwise.

[0039] It is further understood that the terms "comprises," "includes," or "has," when used in this specification, specify the presence of the specified features, regions, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and / or combinations thereof. When an element such as a layer, film, area, or sheet is referred to as being "on top of" another element, it may be directly on top of the other element, or there may be intervening elements. When an element such as a layer, film, area, or sheet is referred to as being "under" another element, it may be directly beneath the other element, or there may be intervening elements.

[0040] Unless otherwise specified, all numbers, values, and / or representations expressing the amounts of components, reaction conditions, polymer compositions, and blends used herein are to be understood as approximate values, including various measurement uncertainties that occur, among other things, in the determination of these values, and should therefore be understood in all cases to be modified by the term "approximately." Furthermore, if a numerical range is disclosed in this description, this is continuous and includes all values ​​from the minimum value of the range to its maximum value, unless otherwise stated. Furthermore, if such a range refers to integer values, all integer values ​​including the minimum value up to the maximum value are included, unless otherwise stated.

[0041] Fig. 1 shows a metal battery according to the prior art. A conventional metal battery 900 includes a first electrode 910, a second electrode 920, and an ion exchange membrane 930 disposed between the first electrode 910 and the second electrode 920. The first electrode 910 may be immersed in a first electrolyte 940, and the second electrode 920 may be immersed in a second electrolyte 950. The first electrode 910 may comprise zinc (Zn). The second electrode 920 may comprise a metal foam and an active metal on a support. For example, the second electrode 920 may be a structure in which platinum on a carbon support is deposited on a metal foam.

[0042] In the conventional metal battery 900, the second electrode 920 serves as both a reduction electrode and an oxidation electrode. During discharge, the first electrode 910 ionizes to Zn(OH 4 ) 2-and generates electrons. The electrons migrate to the second electrode 920, and hydrogen is generated at the second electrode 920. In this case, the second electrode 920 acts as a reduction electrode. During charging, the Zn(OH 4 ) 2- reduced to zinc, and at the second electrode 920, water in the second electrolyte 950 is electrochemically decomposed, producing oxygen. In this case, the second electrode 920 acts as an oxidation electrode.

[0043] In the conventional metal battery 900, hydrogen and oxygen are generated at the second electrode 920 during charging and discharging, respectively. If oxygen is generated at the second electrode 920, the carbon support of the second electrode 920 may corrode. As a result, the performance and service life of the conventional metal battery 900 may deteriorate. In addition, the structure of the second electrode 920 is complicated, and overvoltage is highly likely to occur because it is necessary to combine the metal foam and platinum on the carbon support so that the second electrode 920 can function as both an oxidation electrode and a reduction electrode. In addition, since hydrogen and oxygen are generated in the same space on the second electrode 920, there is a risk that the two gases will mix and cause ignition, explosion, etc.

[0044] The present disclosure aims to solve the above-mentioned problems of the prior art and is characterized by a metal battery consisting of three electrodes so that discharge and charge sections are separated from each other. Fig. 2 shows a hydrogen generation and carbon dioxide storage system according to a first embodiment of the present disclosure. The hydrogen generation and carbon dioxide storage system 1 includes: a first electrolyte circulation unit 200 that separates hydrogen and bicarbonate from a first electrolyte discharged from the metal battery 100 and returns the first electrolyte to the metal battery 100; a second electrolyte circulation unit 300 that separates oxygen from a second electrolyte discharged from the metal battery 100 and returns the second electrolyte to the metal battery 100; and a third electrolyte circulation unit 400 that receives a third electrolyte discharged from the metal battery 100 and returns the third electrolyte to the metal battery 100.

[0045] The metal battery 100 may include an electrode unit 30, a discharge unit 10 disposed on a first side of the electrode unit 30, a charging unit 20 disposed on a second side of the electrode unit 30, a first ion exchange membrane 40 disposed between the electrode unit 30 and the discharge unit 10, and a second ion exchange membrane 50 disposed between the electrode unit 30 and the charging unit 20.

[0046] The first embodiment of the Fig. 2 is characterized in that the first ion exchange membrane 40 and the second ion exchange membrane 50 are cation exchange membranes.

[0047] The discharge unit 10 may comprise a first space 11 having a predetermined size, a first electrolyte 12 accommodated in the first space 11, and a reduction electrode 13 at least partially immersed in the first electrolyte 12.

[0048] The first space 11 may be an interior space of an object having a predetermined shape, such as a container, or may be a space defined by adjacent parts connected to each other. The shape, size, etc. of the first space 11 are not particularly limited.

[0049] The first electrolyte 12 contains water as its main component. After dissolving carbon dioxide in the water contained in the first electrolyte circulation unit 200, which will be described later, the products can be stored in the first space 11.

[0050] When carbon dioxide is dissolved in water, hydrogen cations and bicarbonate anions are formed according to the reaction formula: CO 2 (g) + H 2 O(1) → H + (aq) + HCO 3 - (aq) . The hydrogen cations encounter electrons at the reduction electrode 13, which will be described later, and become hydrogen gas, and the bicarbonate anions react with potassium cations (K+) or sodium cations (Na+) that have passed through the first ion exchange membrane 40 into the first space 11 to form bicarbonate.

[0051] Thus, the first electrolyte 12 may contain water, unreacted carbon dioxide, hydrogen gas and bicarbonate.

[0052] The reduction electrode may comprise a support and a catalytic metal loaded on the support. The shape of the reduction electrode 13 is not particularly limited and may, for example, be a sheet shape with a predetermined thickness.

[0053] The support is not particularly limited and may include at least one selected from the group consisting of, but not limited to, carbon paper, carbon fiber, carbon felt, carbon black, carbon cloth, metal foam, metallic thin film, and combinations thereof. The catalytic metal is not particularly limited in type and may include, for example, platinum (Pt).

[0054] The discharge unit 20 may comprise a second space 21 having a predetermined size, a second electrolyte 22 accommodated in the second space 21, and an oxidation electrode 23 at least partially immersed in the second electrolyte 22.

[0055] The second space 21 may be an interior space of an object having a predetermined shape, such as a container, or may be a space defined by adjacent parts connected to each other. The shape, size, etc. of the second space 21 are not particularly limited.

[0056] The second electrolyte 22 contains water as its main component. Preferably, the second electrolyte 22 comprises at least one selected from the group consisting of potassium hydroxide (KOH), sodium hydroxide (NaOH), and combinations thereof. The second electrolyte 22 may comprise an aqueous solution of potassium hydroxide (KOH), an aqueous solution of sodium hydroxide (NaOH), or the like. The concentration of the potassium hydroxide (KOH), sodium hydroxide (NaOH), etc. is not particularly limited and may, for example, be in a range of 3 M to 6 M. Assuming that the second electrolyte 22 is an aqueous solution of potassium hydroxide (KOH), the potassium hydroxide may be in the form of potassium cations (K+) and hydroxide ions (OH-). The potassium cations (K+) migrate through the second ion exchange membrane 50 to the electrode unit 30, and the hydroxide ions (OH-) convert into oxygen gas, water, and electrons at the oxidation unit 23. This will be described later.

[0057] Accordingly, the second electrolyte 22 may further comprise oxygen gas in addition to the main component.

[0058] The oxidation electrode 23 may comprise nickel foam. The shape of the oxidation electrode 23 is not particularly limited and may, for example, be a sheet shape with a predetermined thickness.

[0059] The electrode unit 30 may include a third space 31 having a predetermined size, a third electrolyte 32 accommodated in the third space 31, and a metal electrode 33 at least partially immersed in the third electrolyte 32.

[0060] The third space 31 may be an interior space of an object with a predetermined shape, such as a container, or a space defined by adjacent parts connected to each other. The shape, size, etc. of the second space 31 are not particularly limited.

[0061] The third electrolyte 32 may contain an alkali metal hydroxide as its main component. Preferably, the third electrolyte 23 comprises at least one selected from the group consisting of potassium hydroxide (KOH), sodium hydroxide (NaOH), and combinations thereof.

[0062] The metal electrode 33 may comprise any material capable of ionizing and generating electrons in the third electrolyte 32. For example, the metal electrode 33 may include at least one selected from the group consisting of lithium (Li), sodium (Na), magnesium (Mg), zinc (Zn), aluminum (Al), and combinations thereof. Preferably, the metal electrode 33 may include at least one selected from the group consisting of magnesium (Mg), zinc (Zn), aluminum (Al), and combinations thereof. Magnesium (Mg), zinc (Zn), and aluminum (Al) are stable in water. Therefore, the metal electrode may preferably be disposed in a water-based system. More preferably, the metal electrode 33 may include at least one selected from the group consisting of magnesium (Mg), zinc (Zn), aluminum (Al), and combinations thereof. Even more preferably, zinc (Zn) and aluminum (Al) may be included, given global reserves and prices.

[0063] The shape of the metal electrode 33 is not particularly limited and may, for example, be a sheet shape having a predetermined thickness.

[0064] Assuming that the metal electrode 33 is made of zinc (Zn), the zinc (Zn) transforms into zinc ions, Zn(OH) when the metal battery 100 is discharged. 4 2- Accordingly, the third electrolyte 32 may further contain zinc ions, Zn (OH) 4 2- , include.

[0065] The metal electrode 33 may be electrically connected to the reduction electrode 13 via a conductor or the like. The metal electrode 33 may be electrically connected to the oxidation electrode 23 via a conductor or the like. Accordingly, the electrons E generated by the reaction in the metal battery 100 can move between the reduction electrode 13, the oxidation electrode 23, and the metal electrode 33 via the conductors or the like.

[0066] The first ion exchange membrane 40 and the second ion exchange membrane 50 may each comprise a cation exchange membrane. The cation exchange membrane may be made of a cation-conductive material. The cation-conductive material is not particularly limited in its type. Examples of the cation-conductive material include perfluorosulfonic acid-based polymers such as Nafion, ion-transfer materials such as Nasicon, and the like.

[0067] The first ion exchange membrane 40 can allow the movement of cations between the first space 11 and the third space 31, but blocks the movement of the first electrolyte 12 and the third electrolyte 32.

[0068] The second ion exchange membrane 50 can allow the movement of cations between the second space 21 and the third space 31, but blocks the movement of the second electrolyte 22 and the third electrolyte 32.

[0069] The first electrolyte circulation unit 200 may include a hydrogen separator 210, a reactor 220, a filter device 230, and a first electrolyte supply 240.

[0070] The hydrogen separator 210 may separate hydrogen contained in the first electrolyte 12 discharged from the discharge unit 10. The hydrogen separator 210 may include a gas-liquid separator for separating hydrogen gas.

[0071] Reactor 220 may be located downstream of hydrogen separator 210. In reactor 220, the externally supplied carbon dioxide may be dissolved in water. The water may include the water contained in first electrolyte 12 and / or externally supplied water. Hydrogen cations and bicarbonate anions are dissolved in first electrolyte 12 through a dissolution reaction of carbon dioxide, expressed by the reaction formula CO 2 (g) + H 2 O(1) → H +(aq) + HCO 3 - (aq), and supplied to the first space 11 through the downstream devices. The hydrogen cations are converted into hydrogen gas at the reduction electrode 13, and the bicarbonate anions are converted into alkaline bicarbonate at the reduction electrode 13. This will be described in detail below.

[0072] The filter device 230 may be located downstream of the reactor 220 and may precipitate the alkaline bicarbonate contained in the first electrolyte 12. The filter 230 may include a cooler to reduce the temperature of the first electrolyte 12 to cause the precipitation of alkaline bicarbonate, and a filter to filter out the precipitated alkaline bicarbonate.

[0073] The first electrolyte supply 240 may be arranged downstream of the filter device 230 and may return the first electrolyte 12, from which hydrogen gas and alkaline bicarbonate have been removed, to the first space 11.

[0074] The second electrolyte circulation unit 300 may include an oxygen separator 310 and a second electrolyte supply 320.

[0075] The oxygen separator 310 may separate oxygen contained in the second electrolyte 22 discharged from the charging unit 20. The oxygen separator 310 may include a gas-liquid separator for separating oxygen gas.

[0076] The second electrolyte supply 320 may be arranged downstream of the oxygen separator 310 and may return the second electrolyte 12, from which oxygen gas and alkaline bicarbonate have been removed, to the second space 22.

[0077] Since the second electrolyte 22 is ionized and consumed during charging and discharging of the metal battery 100, a fresh second electrolyte can be supplied from the outside to the second electrolyte supply 320.

[0078] The third electrolyte circulation unit 400 can receive the third electrolyte 32 discharged from the electrode unit 30 and return the third electrolyte 32 to the third space 31 so that the third electrolyte 32 can circulate.

[0079] During the discharging process of the metal battery 100, the metal electrode 33 of the electrode unit 30 is ionized by the third electrolyte 32, and the reaction represented by the following reaction formula 1 can take place. M(s) + aOH - (aq) -> M(OH)a b- (aq) + (ab)e - Reaction formula 1:

[0080] In reaction formula 1, M may comprise at least one selected from the group consisting of lithium (Li), sodium (Na), magnesium (Mg), zinc (Zn), aluminum (Al), and combinations thereof.

[0081] Where a can be an integer in the range 1 to 5.

[0082] Where b can be a value (a - oxidation number of M) obtained by subtracting an oxidation number of M from a.

[0083] A non-limiting example of the reaction formula 1 may be at least one of the following reaction formulas 1-1 to formula 1-5. Zn(s) + 40H - (aq) → Zn(OH) 4 2- (aq) + 2e - Reaction formula 1-1: Li(s) + OH - (aq) → LiOH(aq) + e - Reaction formula 1-2: Na(S) + OH - (aq) → NaOH (aq) + e - Reaction formula 1-3: Mg(s) + 20H - (aq) → Mg(OH) 2 (aq) + 2e - Reaction formula 1-4: Zn(s) + 3OH - (aq) → Zn(OH) 2 -(aq) + 3e - Reaction formula 1-5:

[0084] The alkaline cations, K+ or Na+, of the third electrolyte 32 migrate through the first ion exchange membrane 40 to the discharge unit 10, where the alkaline cations react with the bicarbonate ions (HCO3 - ) and form alkaline bicarbonate. The alkaline bicarbonate can be separated and recovered from the first electrolyte circulation unit 200 as described above.

[0085] The electrons generated according to reaction formula 1 are transferred to the reduction electrode 13 via a conductor, and the reaction represented by the following reaction formula 2 can occur at the reduction electrode 13. 2H + (aq) + 2e - → H 2 (g) Reaction formula 2:

[0086] The hydrogen gas generated according to reaction formula 2 can be separated and recovered by the first electrolyte circulation unit 200 as described above.

[0087] When the metal battery 100 is charged, the M(OH) produced according to reaction formula 1 a b- (aq) with the electrons that have migrated from the oxidation electrode 23 to the metal electrode 33 and is thereby reduced to M(s) by the reaction of the following reaction formula 3. M(OH)a b- (aq) + (ab)e - -> M(s) + aOH - (aq) Reaction formula 3:

[0088] In reaction formula 3, M, a and b refer to the same as in reaction formula 1.

[0089] A non-limiting example of the reaction formula 3 may be at least one of the following reaction formulas 3-1 to 3-5. Zn(OH) 4 2- (aq) + 2e - → Zn(s) + 40H -(aq) Reaction formula 3-1: LiOH (aq) + e - → Li(s) + OH - (aq) Reaction formula 3-2: NaOH(aq) + e - → Na (S) + OH - (aq) Reaction formula 3-3: Mg(OH) 2 (aq) + 2e - → Mg (s) + 2OH - (aq) Reaction formula 3-4: Al(OH) 3 (aq) + 3e - → Al (s) + 3OH - (aq) Reaction formula 3-5:

[0090] The electrons are generated by the following reaction formula 4, which occurs at the oxidation electrode 23. 40H - (aq) → O 2 (g) + 2H 2 O(l) + 4e - Reaction formula 4:

[0091] As the hydroxide ions are consumed, the alkaline cations, K+ or Na+, contained in the second electrolyte 22 can migrate through the second ion exchange membrane 50 to the electrode unit 30.

[0092] The third electrolyte 32 of the electrode unit 30 can be circulated by the third electrolyte circulation unit 500 for ionization and reduction control of the metal electrode 33 during charging and discharging of the metal battery.

[0093] Fig. 3 shows a system for generating hydrogen and storing carbon dioxide according to a second embodiment of the present disclosure. The second embodiment of the system shown in Fig. 3 is characterized in that a first ion exchange membrane 40 and a second ion exchange membrane 50 are each a cation exchange membrane and an anion exchange membrane.

[0094] The configuration of the second embodiment is the same as that of the first embodiment except for the first ion exchange membrane 40 and the second ion exchange membrane 50. Therefore, redundant description of the same parts is omitted.

[0095] The first electrolyte membrane 40 may comprise a cation exchange membrane. The cation exchange membrane may be made of a cation-conductive material. The cation-conductive material is not particularly limited in its type. Examples of the cation-conductive material include perfluorosulfonic acid-based polymers such as Nafion, ion-transfer materials such as Nasicon, and the like.

[0096] The first ion exchange membrane 40 can allow the movement of cations between the first space 11 and the third space 31, but blocks the movement of the first electrolyte 12 and the third electrolyte 32.

[0097] The second electrolyte membrane 50 may comprise an anion exchange membrane. The anion exchange membrane may be made of an anion-conducting material. The anion-conducting material is not particularly limited. For example, the anion-conducting material comprises at least one selected from the group consisting of poly(terphenylene), 1,4-diazabicyclo[2,2,2]octane-poly(ethersulfone), poly(arylpiperidinium), poly(phenylene oxide)-block-poly(vinylbenzyltrimethylammonium), and combinations thereof.

[0098] The second ion exchange membrane 50 can allow the movement of anions between the second space 21 and the third space 31, but blocks the movement of the second electrolyte 22 and the third electrolyte 32.

[0099] During the discharging process of the metal battery 100, the metal electrode 33 of the electrode unit 30 is ionized by the third electrolyte 32, and the reaction represented by the following reaction formula 1 may occur. M(s) + aOH - (aq) → M(OH) a b- (aq) + (ab) e - Reaction formula 1:

[0100] In reaction formula 1, M may comprise at least one selected from the group consisting of lithium (Li), sodium (Na), magnesium (Mg), zinc (Zn), aluminum (Al), and combinations thereof.

[0101] Where a can be an integer in the range 1 to 5.

[0102] Where b can be a value (a - oxidation number of M) obtained by subtracting an oxidation number of M from a.

[0103] A non-limiting example of the reaction formula 1 may be at least one of the above reaction formulas 1-1 to 1-5.

[0104] The alkaline cations, K+ or Na+, of the third electrolyte 32 move through the first ion exchange membrane 40 to the discharge unit 10, where the alkaline cations react with the bicarbonate ions (HCO3 - ) to produce alkaline bicarbonate. The alkaline bicarbonate can be separated and recovered from the first electrolyte circulation unit 200 as described above.

[0105] The electrons generated according to reaction formula 1 are transferred via a conductor to the reduction electrode 13, and the reaction represented by the following reaction formula 2 can take place at the reduction electrode 13. 2H + (aq) + 2e - → H 2 (g) Reaction formula 2:

[0106] The hydrogen gas generated according to reaction formula 2 can be separated and recovered by the first electrolyte circulation unit 200 as described above.

[0107] When the metal battery 100 is charged, the M(OH) produced according to reaction formula 1 a b- (aq) with the electrons that have migrated from the oxidation electrode 23 to the metal electrode 33 and is thereby reduced to M(s) by the reaction of the following reaction formula 3. M(OH) a b- (aq) + (ab) e - → M(s) + aOH - (aq) Reaction formula 3:

[0108] In reaction formula 3, M, a and b refer to the same as in reaction formula 1.

[0109] A non-limiting example of the reaction formula 3 may be at least one of the above reaction formulas 3-1 to 3-5.

[0110] The hydroxide ions can migrate through the second ion exchange membrane 50 into the charging unit 20. The reaction represented by reaction formula 4 can occur at the oxidation electrode 23. 40H - (aq) → O 2(g) + 2H 2 O(l) + 4e - Reaction formula 4:

[0111] The electrons migrate via a conductor connected to the oxidation electrode 23 to the metal electrode 33 and react according to reaction formula 3.

[0112] The third electrolyte 32 of the electrode unit 30 is consumed because alkaline cations K+ or Na+ and hydroxide ions migrate through the first ion exchange membrane 40 and the second ion exchange membrane 50 into the discharge unit 10 and the charge unit 20 during charging and discharging of the battery. Therefore, the third electrolyte circulation unit 400 can be replenished with a fresh third electrolyte from the outside.

[0113] Fig. Figure 4 shows a metal battery according to an embodiment of the present disclosure. The metal battery 100 may include a discharge unit 10, a charge unit 20, an electrode unit 30, a first ion exchange membrane 40 disposed between the discharge unit 10 and the electrode unit 30, and a second ion exchange membrane 50 disposed between the charge unit 20 and the electrode unit 30.

[0114] The discharge unit 10 may include a first body plate 14 having a plate shape, a reducing electrode current collector 15 disposed on a first surface of the first body plate 14 and having a sheet shape, and a first spacer 16 having a frame shape disposed between the reducing electrode current collector 15 and the first ion exchange membrane 40 to define the first space 11.

[0115] The reduction electrode 13 may be arranged on a first surface of the reduction electrode current collector 15.

[0116] Fig. 5A shows the first spacer 16. The first spacer 16 may include a first electrolyte inlet 16a formed to extend through a first portion of a flank thereof and configured to enable communication between the first space 11 and an external environment, and a first electrolyte outlet 16b formed to extend through a second portion of the flank thereof and configured to enable communication between the first space 11 and the external environment, the second portion being spaced apart from the first portion.

[0117] The charging unit 20 may include: a second body plate 24 having a plate shape, an oxidation electrode current collector 25 disposed on a first surface of the second body plate 24 and having a sheet shape, and a second spacer 26 having a frame shape and disposed between the oxidation electrode current collector 25 and the second ion exchange membrane 50 to define the second space 21.

[0118] The oxidation electrode 23 may be arranged on a first surface of the oxidation electrode current collector 25.

[0119] Fig. 5B shows the second spacer 26. The second spacer 26 may comprise a second electrolyte inlet 26a formed to extend through a first portion of a flank thereof and configured to enable communication between the second space 21 and the external environment, and a second electrolyte outlet 26b formed to extend through a second portion of the flank thereof and configured to enable communication between the second space 21 and the external environment, the second portion being spaced apart from the first portion.

[0120] The electrode unit 30 may include a sheet-shaped metal electrode current collector 34, a third spacer 35 disposed between the metal electrode current collector 34 and the first ion exchange membrane 40, and a fourth spacer 36 disposed between the metal electrode current collector 34 and the second ion exchange membrane 50.

[0121] The third spacer 35 and the fourth spacer 36 may form the third space 31.

[0122] The metal electrode 33 may be arranged on both surfaces of the metal electrode current collector 34.

[0123] Fig. 5C shows the third spacer 35. The third spacer 35 may comprise a third electrolyte inlet 35a formed to extend through a first portion of a flank thereof and configured to enable communication between the third space 31 and the external environment, and a third electrolyte outlet 35b formed to extend through a second portion of the flank thereof and configured to enable communication between the third space 31 and the external environment, the second portion being spaced from the first portion.

[0124] Fig. 5D shows the fourth spacer 36. The fourth spacer 36 may comprise a third electrolyte inlet 35a formed to extend through a first portion of a flank thereof and configured to enable communication between the third space 31 and the external environment, and a third electrolyte outlet 35b formed to extend through a second portion of the flank thereof and configured to enable communication between the third space 31 and the external environment, the second portion being spaced from the first portion.

[0125] Other embodiments of the disclosure will be described in more detail with reference to the examples described below. The examples described below are provided merely to facilitate understanding of the present disclosure, and the scope of the present disclosure is not limited thereto. Example 1

[0126] A metal battery, as in Fig. 3 was prepared. A cation exchange membrane was used as the first ion exchange membrane and an anion exchange membrane as the second ion exchange membrane. A reduction electrode was platinum on a carbon support (Pt / C), an oxidation electrode was nickel foam, and a metal electrode was zinc (Zn). The first electrolyte was a 3 M aqueous solution of KHCO 3 , the second and third electrolyte an aqueous solution with 6 M KOH. Example 2

[0127] A metal battery, as in Fig. 2 was prepared. A first ion exchange membrane and a second ion exchange membrane were a cation exchange membrane. The remaining parts of the configuration were the same as in Example 1. Comparative example

[0128] A conventional metal battery, as in Fig. 1 was fabricated. An ion exchange membrane was a cation exchange membrane. A first metal was zinc (Zn), and a second metal was platinum on a carbon support (Pt / C) deposited on nickel foam.

[0129] A first electrolyte was an aqueous solution containing 6 M KOH and a second electrolyte was an aqueous solution containing 3 M KHCO3.

[0130] Fig. Figure 6 shows a result of the performance comparison between the metal battery of Example 1 and the metal battery of Comparative Example. The left side of the figure shows the performance of the metal battery of Comparative Example, and the right side of the figure shows the performance of the metal battery of Example 1. In the case of Comparative Example, the voltage increases, and the operating state becomes unstable over charge and discharge cycles. These phenomena result from the corrosion of the carbon support. The metal battery of Example 1 has higher charging efficiency than the metal battery of Comparative Example because the voltage is lower by about 1.1 V. Furthermore, it is confirmed that the charging and discharging of the battery of Example 1 is stable compared to the battery of Comparative Example.

[0131] Fig.Figure 7 shows performance measurements of a metal battery of Example 2. The battery of Example 2 exhibits the same performance as that of Example 1, with a voltage of about 2.1 V during charging. It is confirmed that the battery of Example 2 is stably charged and discharged.

[0132] Although examples and experimental examples according to the present disclosure have been described for exemplary purposes, those skilled in the art will recognize that various modifications, additions, and substitutions are possible without departing from the scope and spirit of the disclosures as defined in the appended claims.

Claims

[1] Metal battery, comprising: an electrode unit comprising a metal electrode; a discharge unit arranged on a first side of the electrode unit; a charging unit arranged on a second side of the electrode unit; a first ion exchange membrane disposed between the electrode unit and the discharge unit; and a second ion exchange membrane disposed between the electrode unit and the charging unit; wherein the discharge unit comprises a first space having a predetermined size, a first electrolyte accommodated in the first space, and a reduction electrode at least partially immersed in the first electrolyte; wherein the charging unit comprises a second space having a predetermined size, a second electrolyte accommodated in the second space, and an oxidation electrode at least partially immersed in the second electrolyte; and wherein the electrode unit comprises a third space having a predetermined size, a third electrolyte accommodated in the third space, and the metal electrode at least partially immersed in the third electrolyte. [2] The metal battery according to claim 1, wherein the metal electrode comprises at least one selected from the group consisting of lithium (Li), sodium (Na), magnesium (Mg), zinc (Zn), aluminum (Al), and combinations thereof. [3] A metal battery according to claim 1, wherein the reduction electrode comprises a carrier and a catalytic metal loaded on the carrier. [4] A metal battery according to claim 1, wherein the oxidation electrode comprises nickel foam. [5] A metal battery according to claim 1, wherein the discharge unit further comprises: a first body plate having a plate shape; a reduction electrode current collector disposed on a first surface of the first body plate and having a sheet shape; and a first spacer having a frame shape and disposed between the reduction electrode current collector and the first ion exchange membrane to define the first space, wherein the reducing electrode is arranged on a first surface of the reducing electrode current collector. [6] A metal battery according to claim 5, wherein the first spacer comprises: a first electrolyte inlet extending through a first portion of a flank of the first spacer and configured to enable communication between the first space and an external environment; and a first electrolyte outlet extending through a second portion of the flank of the first spacer and configured to enable communication between the first space and the external environment, the second portion being spaced from the first portion. [7] A metal battery according to claim 1, wherein the charging unit further comprises: a second body plate having a plate shape; an oxidation electrode current collector disposed on a first surface of the second body plate and having a sheet shape; and a second spacer having a frame shape and disposed between the oxidation electrode current collector and the second ion exchange membrane to define the second space; wherein the oxidation electrode is arranged on a first surface of the oxidation electrode current collector. [8] A metal battery according to claim 7, wherein the second spacer comprises: a second electrolyte inlet extending through a first portion of a flank of the second spacer and configured to enable communication between the second space and an external environment; and a second electrolyte outlet extending through a second portion of the flank of the second spacer and configured to enable communication between the second space and the external environment, the second portion being spaced from the first portion. [9] A metal battery according to claim 1, wherein the electrode comprises: a metal electrode current collector having a sheet metal shape; a third spacer disposed between the metal electrode current collector and the first ion exchange membrane; and a fourth spacer disposed between the metal electrode current collector and the second ion exchange membrane; wherein the third spacer and the fourth spacer form the third space; and wherein the metal electrode is arranged on both surfaces of the metal electrode current collector. [10] A metal battery according to claim 9, wherein at least one of the third spacer and the fourth spacer comprises: a third electrolyte inlet extending through a first portion of a flank of the respective spacer and configured to enable communication between the third space and an external environment; and a third electrolyte outlet extending through a second portion of the flank of the corresponding spacer and configured to enable communication between the third space and the external environment, the first portion being spaced from the second portion. [11] The metal battery according to claim 1, wherein the first space and the third space are separated from each other by the first ion exchange membrane, and wherein the second space and the third space are separated from each other by the second ion exchange membrane. [12] The metal battery according to claim 1, wherein the first ion exchange membrane comprises a cation exchange membrane, and the second ion exchange membrane comprises a cation exchange membrane. [13] The metal battery according to claim 1, wherein the first ion exchange membrane comprises a cation exchange membrane, and the second ion exchange membrane comprises an anion exchange membrane. [14] A metal battery according to claim 1, wherein the first electrolyte comprises water and bicarbonate. [15] The metal battery of claim 1, wherein the second electrolyte comprises at least one selected from the group consisting of potassium hydroxide (KOH), sodium hydroxide (NaOH), and combinations thereof. [16] The metal battery of claim 1, wherein the third electrolyte comprises at least one selected from the group consisting of potassium hydroxide (KOH), sodium hydroxide (NaOH), and combinations thereof. [17] A metal battery according to claim 1, wherein, upon discharging, a reaction represented by reaction formula 1 occurs at the electrode unit and a reaction represented by reaction formula 2 occurs at the discharge unit, wherein reaction formula 1 is M(s) + aOH - (aq) → M(OH) a b- (aq) + (ab) e - , wherein in the reaction formula 1 M comprises at least one selected from the group consisting of lithium (Li), sodium (Na), magnesium (Mg), zinc (Zn), aluminum (Al) and combinations thereof, a is an integer in a range from 1 to 4, and b is a value obtained by subtracting an oxidation number of M from a; and where the reaction formula 2 2H + (aq) + 2e - → H2(g) is. [18] A metal battery according to claim 1, wherein, upon charging, a reaction represented by reaction formula 3 occurs at the electrode unit and a reaction represented by reaction formula 4 occurs at the charging unit, wherein reaction formula 3 is M(OH) a b- (aq) + (ab)e - → M(s) + aOH - (aq), wherein in the reaction formula 3 M comprises at least one selected from the group consisting of lithium (Li), sodium (Na), magnesium (Mg), zinc (Zn), aluminum (Al) and combinations thereof, a is an integer in a range of 1 to 4, and b is a value obtained by subtracting an oxidation number of M from a; and where the reaction formula 4 40H - (aq) → O2(g) + 2H2O(1) + 4e - is. [19] System for producing hydrogen and storing carbon dioxide, comprising: the metal battery according to claim 1; a first electrolyte circulation unit connected to the metal battery for receiving the first electrolyte discharged from the discharge unit, the first electrolyte circulation unit being configured to separate the hydrogen contained in the first electrolyte and supply the first electrolyte to the discharge unit; a second electrolyte circulation unit connected to the metal battery for receiving the second electrolyte discharged from the charging unit, the second electrolyte circulation unit being configured to separate the oxygen contained in the second electrolyte and supply the second electrolyte to the charging unit; and a third electrolyte circulation unit connected to the metal battery and configured to receive the third electrolyte discharged from the electrode unit and supply the third electrolyte to the electrode unit.

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