Rechargeable metal battery

Abstract

The present invention provides a rechargeable metal battery with improved efficiency and a hydrogen generation and carbon dioxide storage system equipped with such a battery. A metal battery according to an embodiment includes an electrode unit including 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 interposed between the electrode unit and the discharging unit, and a second ion exchange membrane interposed between the electrode unit and the charging unit.

Description

Technical Field

[0001] The present invention relates to rechargeable metal batteries with improved efficiency, and hydrogen generation and carbon dioxide storage systems equipped with such batteries. Background Art

[0002] Conventional metal batteries pose 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 carrying the active metal, thereby deteriorating battery performance and durability. In addition, since the material constituting the oxidation electrode and the material constituting the reduction electrode must exist at the same time, the electrode composition is complicated, and the battery cannot achieve the expected performance due to the overvoltage generated during battery operation.

[0004] In addition, since oxygen and hydrogen are present in the same space, there is a risk of the two gases mixing and causing fire, explosion, etc. Summary of the invention

[0005] In one aspect, the present invention provides a rechargeable metal battery that can operate reliably.

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

[0007] The objects of the present invention are not limited to the above objects. The above and other objects of the present invention will become more apparent from the following description and will be achieved by the means defined in the claims and the combination of these means.

[0008] A metal battery according to one embodiment of the present invention includes: an electrode unit including 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 between the electrode unit and the discharge unit, and a second ion exchange membrane 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 a metal electrode at least partially immersed in the third electrolyte.

[0009] The metal electrode may include at least one selected from the group consisting of zinc (Zn), aluminum (Al), and a combination thereof.

[0010] The reduction electrode may include a support and a catalytic metal supported on the support.

[0011] The oxidation electrode may comprise nickel foam.

[0012] The discharge unit may further include a first body plate having a plate shape, a reduction electrode 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 interposed between the reduction electrode collector and the first ion exchange membrane to form a first space. The reduction electrode may be disposed on the first surface of the reduction electrode collector.

[0013] The first separator may include: a first electrolyte inflow portion formed as a first portion passing through a side of the first separator and configured to enable communication between the first space and an external environment; and a first electrolyte outflow portion formed as a second portion spaced apart from the first portion passing through a side of the first separator and configured to enable communication between the first space and the external environment.

[0014] 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 and interposed between the oxidation electrode current collector and the second ion exchange membrane to form a second space. The oxidation electrode may be disposed on the first surface of the oxidation electrode current collector.

[0015] The second separator may include: a second electrolyte inflow portion formed as a first portion passing through a side of the second separator and configured to enable communication between the second space and the external environment; and a second electrolyte outflow portion formed as a second portion spaced apart from the first portion passing through a side of the second separator and configured to enable communication between the second space and the external environment.

[0016] The electrode unit may also include an electrode current collector having a sheet shape, a third spacer between the metal electrode current collector and the first ion exchange membrane, and a fourth spacer between the metal electrode current collector and the second ion exchange membrane. The third spacer and the fourth spacer form a third space, and the metal electrode may be disposed on both surfaces of the metal electrode current collector.

[0017] Each of the third and fourth spacers may include a third electrolyte inflow portion formed as a first portion passing through a side of the corresponding spacer and configured to enable communication between the third space and the external environment; and a third electrolyte outflow portion formed as a second portion spaced apart from the first portion passing through a side of the corresponding spacer and configured to enable communication between the third space and the external environment.

[0018] The first space and the third space may be separated by a first ion exchange membrane, and the second space and the third space may be separated by a second ion exchange membrane.

[0019] The first ion exchange membrane may include a cation exchange membrane, and the second ion exchange membrane may include a cation exchange membrane.

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

[0021] The first electrolyte may include water and bicarbonate.

[0022] The second electrolyte may include at least one selected from the group consisting of potassium hydroxide (KOH), sodium hydroxide (NaOH), and a combination thereof.

[0023] The third electrolyte may include at least one selected from the group consisting of potassium hydroxide (KOH), sodium hydroxide (NaOH), and a combination thereof.

[0024] The metal battery may be configured such that, during discharge, a reaction represented by the following reaction formula 1 occurs in the electrode unit, and a reaction represented by the following reaction formula 2 occurs in the discharge unit.

[0025] Reaction 1:

[0026] M(s)+aOH - (aq)→M(OH) a b- (aq)+(ab)e -

[0027] In Reaction Formula 1, M may include at least one selected from the group consisting of lithium (Li), sodium (Na), magnesium (Mg), zinc (Zn), aluminum (Al), and combinations thereof.

[0028] Wherein a can be an integer in the range of 1 to 5.

[0029] Here, b may be a value obtained by subtracting the oxidation number of M from a (the oxidation number of aM).

[0030] Reaction 2:

[0031] 2H + (aq)+2e - →H 2 (g)

[0032] The metal battery may be configured such that, when charged, a reaction represented by the following reaction formula 3 occurs in the electrode unit, and a reaction represented by the following reaction formula 4 occurs in the charging unit.

[0033] Reaction 3:

[0034] M(OH) a b- (aq)+(ab)e - →M(s)+aOH- (aq)

[0035] In Reaction Formula 3, M may include at least one selected from the group consisting of lithium (Li), sodium (Na), magnesium (Mg), zinc (Zn), aluminum (Al), and combinations thereof.

[0036] Wherein a can be an integer in the range of 1 to 5.

[0037] Here, b may be a value obtained by subtracting the oxidation number of M from a (the oxidation number of aM).

[0038] Reaction 4:

[0039] 4OH - (aq)→O 2 (g)+2H 2 O(l)+4e -

[0040] Another aspect of the present invention provides a hydrogen generation and carbon dioxide storage system, which includes: a metal battery; a first electrolyte circulation unit, which is connected to the metal battery and is configured to receive a first electrolyte discharged from a discharge unit, separate the hydrogen contained in the first electrolyte, and supply the first electrolyte to the discharge unit; a second electrolyte circulation unit, which is connected to the metal battery and is configured to receive a second electrolyte discharged from a charging unit, separate the oxygen contained in the second electrolyte, and supply the second electrolyte to the charging unit; and a third electrolyte circulation unit, which is connected to the metal battery and is configured to receive a third electrolyte discharged from an electrode unit and supply the third electrolyte to the electrode unit.

[0041] According to the present invention, a rechargeable metal battery capable of reliable operation can be obtained.

[0042] According to the present invention, a rechargeable metal battery with improved efficiency can be obtained.

[0043] Advantages of the present invention are not limited to the above advantages. It should be understood that the advantages of the present invention include all effects that can be inferred from the description given below. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A metal battery according to the related art is shown;

[0045] Figure 2 A hydrogen generation and carbon dioxide storage system according to a first embodiment of the present invention is shown;

[0046] Figure 3 shows a hydrogen generation and carbon dioxide storage system according to a second embodiment of the present invention;

[0047] Figure 4 A metal battery according to one embodiment of the present invention is shown;

[0048] Figure 5A A first spacer is shown;

[0049] Figure 5B A second spacer is shown;

[0050] Figure 5C A third spacer is shown;

[0051] Figure 5D A fourth spacer is shown;

[0052] Figure 6 showing the results of comparison between the performance of the metal battery of Example 1 and the performance of the metal battery of the comparative example; and

[0053] Figure 7 The measurement results of the performance of the metal battery of Example 2 are shown. DETAILED DESCRIPTION

[0054] The above-mentioned purpose, other purposes, features and advantages of the present invention will be easily understood from the following preferred embodiments associated with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and can be embodied in other forms. The embodiments described herein are provided so that the content of the present invention can be thorough and complete, and the spirit of the present invention can be fully conveyed to those skilled in the art.

[0055] In all the drawings, the same elements are represented by the same reference numerals. In the drawings, for the clarity of the disclosure, the size of the structure is larger than the actual size. The terms "first", "second", etc. used in this specification can be used to describe various components, but these components should not be interpreted as being limited to these terms. These terms are only used to distinguish the purpose of one component from another component. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and the second component may also be referred to as the first component. As used herein, the singular forms "one", "an", and "said" are intended to also include plural forms, unless the context clearly indicates otherwise.

[0056] It should also be understood that the terms "comprises," "comprising," or "having" when used in this specification specify the presence of the features, regions, integers, steps, operations, element components, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and / or combinations thereof. It should also be understood that when an element such as a layer, film, region, or sheet is referred to as being "on" another element, it may be directly on the other element, or an intermediate element may be present therebetween. Similarly, when an element such as a layer, film, region, or sheet is referred to as being "under" another element, it may be directly under the other element, or an intermediate element may be present therebetween.

[0057] Unless otherwise indicated, all numbers, values ​​and / or representations representing the amounts of components, reaction conditions, polymer compositions and mixtures used herein should be considered approximate, including various uncertainties that affect measurement that occur inherently when obtaining these values, and should therefore be understood to be modified by the term "about" in all cases. In addition, when a numerical range is disclosed in this specification, the range is continuous and includes all values ​​from the minimum value of the range to its maximum value, unless otherwise indicated. In addition, when such a range belongs to integer values, all integers including the minimum value to the maximum value are included unless otherwise indicated.

[0058] Figure 1 A metal battery according to the related art is shown. A conventional metal battery 900 includes a first electrode 910, a second electrode 920, and an ion exchange membrane 930 inserted 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 include zinc (Zn). The second electrode 920 may include a metal foam and an active metal supported on a carrier. For example, the second electrode 920 may be a structure in which platinum supported on a carbon carrier is applied to the metal foam.

[0059] 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 is ionized into Zn(OH) 4 2- The electrons migrate to the second electrode 920 and generate hydrogen gas at the second electrode 920. In this case, the second electrode 920 acts as a reduction electrode. During charging, Zn(OH) 4 2- is reduced to zinc, and at the second electrode 920, water in the second electrolyte 950 is electrochemically decomposed to generate oxygen. In this case, the second electrode 920 acts as an oxidation electrode.

[0060] In the conventional metal battery 900, hydrogen and oxygen are generated at the second electrode 920 during charging and discharging, respectively. When oxygen is generated at the second electrode 920, the carbon support of the second electrode 920 is corroded. As a result, the performance and life of the conventional metal battery 900 are reduced. In addition, the composition of the second electrode 920 is complex, and it is very likely to generate overvoltage because it is necessary to combine metal foam and platinum supported on a carbon support so that the second electrode 920 can act as an oxidation electrode and a reduction electrode at the same time. 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 mix and cause fire, explosion, etc.

[0061] The present invention is intended to solve the above-mentioned problems of the related art, and is characterized in that a metal battery is composed of three electrodes so that a discharge part and a charge part are separated from each other. Figure 2 A hydrogen generation and carbon dioxide storage system according to a first embodiment of the present invention is shown. The hydrogen generation and carbon dioxide storage system 1 includes: a first electrolyte circulation unit 200, which separates hydrogen and bicarbonate from a first electrolyte discharged from a metal battery 100 and supplies the first electrolyte back to the metal battery 100; a second electrolyte circulation unit 300, which separates oxygen from a second electrolyte discharged from the metal battery 100 and supplies the second electrolyte back to the metal battery 100; and a third electrolyte circulation unit 400, which receives a third electrolyte discharged from the metal battery 100 and supplies the third electrolyte back to the metal battery 100.

[0062] 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 charge unit 20 disposed on a second side of the electrode unit 30, a first ion exchange membrane 40 inserted between the electrode unit 30 and the discharge unit 10, and a second ion exchange membrane 50 inserted between the electrode unit 30 and the charge unit 20.

[0063] Figure 2 The first embodiment of the system shown in FIG. 1 is characterized in that the first ion exchange membrane 40 and the second ion exchange membrane 50 are cation exchange membranes.

[0064] The discharge cell 10 may include a first space 11 of 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 .

[0065] The first space 11 may be an inner space of an object having a predetermined shape, such as a container, or may be a space formed by combining adjacent components. The shape, size, etc. of the first space 11 are not particularly limited.

[0066] The first electrolyte 12 contains water as a main component. After carbon dioxide is dissolved in water contained in the first electrolyte circulation unit 200 (which will be described below), the product may be stored in the first space 11.

[0067] When carbon dioxide dissolves in water, it produces hydrogen cations and bicarbonate anions according to the following reaction: 2 (g)+H 2 O(l)→H + (aq)+HCO 3 - The hydrogen cations encounter electrons (which will be described below) at the reduction electrode 13 to become hydrogen gas, and the bicarbonate anions react with the potassium cations (K + ) or sodium cation (Na + ) to become bicarbonate.

[0068] Thus, the first electrolyte 12 may contain water, unreacted carbon dioxide, hydrogen, and bicarbonate.

[0069] The reduction electrode may include a support and a catalytic metal supported on the support. The shape of the reduction electrode 13 is not particularly limited, and is, for example, in the form of a sheet having a predetermined thickness.

[0070] The carrier is not particularly limited and may contain at least one selected from the group consisting of carbon paper, carbon fiber, carbon felt, carbon black, carbon cloth, metal foam, metal film and combinations thereof, but is not limited thereto. The type of catalytic metal is not particularly limited and may include, for example, platinum (Pt).

[0071] The charging unit 20 may include a second space 21 of 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 .

[0072] The second space 21 may be an inner space of an object having a predetermined shape, such as a container, or may be a space formed by combining adjacent components. The shape, size, etc. of the second space 21 are not particularly limited.

[0073] The second electrolyte 22 contains water as a main component. Preferably, the second electrolyte 22 includes at least one selected from the group consisting of potassium hydroxide (KOH), sodium hydroxide (NaOH), and a combination thereof. The second electrolyte 22 may include an aqueous solution of potassium hydroxide (KOH), an aqueous solution of sodium hydroxide (NaOH), and the like. The concentration of potassium hydroxide (KOH), sodium hydroxide (NaOH), and the like is not particularly limited and may be, for example, in the range of 3M to 6M. Assuming that the second electrolyte 22 is an aqueous solution of potassium hydroxide (KOH), potassium hydroxide may be a potassium cation (K+ ) and hydroxide ions (OH - ) exists in the form of potassium cation (K + ) moves to the electrode unit 30 through the second ion exchange membrane 50, and the hydroxide ions (OH - ) is changed into oxygen, water and electrons at the oxidation electrode 23. This will be described below.

[0074] Therefore, the second electrolyte 22 may further include oxygen in addition to the main component.

[0075] Oxidation electrode 23 may include nickel foam. The shape of oxidation electrode 23 is not particularly limited, and is, for example, a sheet shape having a predetermined thickness.

[0076] The electrode unit 30 may include a third space 31 of 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 .

[0077] The third space 31 may be an inner space of an object having a predetermined shape, such as a container, or may be a space formed by combining adjacent components. The shape, size, etc. of the third space 31 are not particularly limited.

[0078] The third electrolyte 32 may contain an alkali metal hydroxide as a main component. Preferably, the third electrolyte 32 includes at least one selected from the group consisting of potassium hydroxide (KOH), sodium hydroxide (NaOH), and a combination thereof.

[0079] The metal electrode 33 may include 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. Still more preferably, zinc (Zn) and aluminum (Al) may be included in consideration of world reserves and prices.

[0080] The shape of the metal electrode 33 is not particularly limited, and is, for example, in the shape of a sheet having a predetermined thickness.

[0081] Assuming that the metal electrode 33 is zinc (Zn), when the metal battery 100 is discharged, zinc (Zn) becomes zinc ions, Zn(OH) 4 2-Therefore, the third electrolyte 32 may also include zinc ions Zn(OH) 4 2- .

[0082] The metal electrode 33 may be electrically connected to the reduction electrode 13 via a conductor, etc. The metal electrode 33 may be electrically connected to the oxidation electrode 23 via a conductor, etc. Therefore, electrons E generated by the reaction in the metal battery 100 may move between the reduction electrode 13, the oxidation electrode 23, and the metal electrode 33 via a conductor, etc.

[0083] The first ion exchange membrane 40 and the second ion exchange membrane 50 may each include a cation exchange membrane. The cation exchange membrane may be made of a cation conductive material. The type of cation conductive material is not particularly limited. Examples of cation conductive materials include perfluorosulfonic acid-based polymers such as Nafion, ion transport materials such as Nasicon, and the like.

[0084] The first ion exchange membrane 40 may allow cations to move between the first space 11 and the third space 31 , but prevent movement of the first electrolyte 12 and the third electrolyte 32 .

[0085] The second ion exchange membrane 50 may allow cations to move between the second space 21 and the third space 31 , but prevent movement of the second electrolyte 22 and the third electrolyte 32 .

[0086] The first electrolyte circulation unit 200 may include a hydrogen separator 210 , a reactor 220 , a filtering device 230 , and a first electrolyte feeder 240 .

[0087] The hydrogen separator 210 may separate hydrogen contained in the first electrolyte 12 exhausted from the discharge unit 10. The hydrogen separator 210 may include a gas-liquid separation device for separating hydrogen.

[0088] Reactor 220 may be disposed downstream of hydrogen separator 210. In reactor 220, externally supplied carbon dioxide may be dissolved in water. The water may include water contained in first electrolyte 12 and / or externally supplied water. Hydrogen cations and bicarbonate anions are reacted by a reaction formula CO 2 (g)+H 2 O(l)→H + (aq)+HCO 3 - The dissolution reaction of carbon dioxide represented by (aq) dissolves in the first electrolyte 12 and is supplied to the first space 11 through the downstream device. Hydrogen cations are converted into hydrogen gas at the reduction electrode 13, and bicarbonate anions are converted into alkaline bicarbonate at the reduction electrode 13. This will be described in more detail below.

[0089] The filtering device 230 may be disposed downstream of the reactor 220 and separates the alkaline bicarbonate contained in the first electrolyte 12 as a precipitate. The filtering device 230 may include a cooler for lowering the temperature of the first electrolyte 12 to cause precipitation of the alkaline bicarbonate and a filter for filtering out the precipitated alkaline bicarbonate.

[0090] The first electrolyte feeder 240 may be disposed downstream of the filtering device 230 , and may return the first electrolyte 12 from which hydrogen and alkali metal bicarbonate have been removed to the first space 11 .

[0091] The second electrolyte circulation unit 300 may include an oxygen separator 310 and a second electrolyte feeder 320 .

[0092] The oxygen separator 310 may separate oxygen contained in the second electrolyte 22 exhausted from the charging unit 20. The oxygen separator 310 may include a gas-liquid separation device for separating oxygen.

[0093] The second electrolyte feeder 320 may be disposed downstream of the oxygen separator 310 , and may return the second electrolyte 22 from which oxygen and alkali metal bicarbonate have been removed to the second space 21 .

[0094] Since the second electrolyte 22 is ionized and consumed during charge and discharge of the metal battery 100 , fresh second electrolyte may be supplied to the second electrolyte feeder 320 from the outside.

[0095] The third electrolyte circulation unit 400 may 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 may circulate.

[0096] During a discharge operation of the metal battery 100 , the metal electrode 33 of the electrode unit 30 is ionized by the third electrolyte 32 , and a reaction represented by the following Reaction Formula 1 may occur.

[0097] Reaction 1:

[0098] M(s)+aOH - (aq)→M(OH) a b- (aq)+(ab)e -

[0099] In Reaction Formula 1, M may include at least one selected from the group consisting of lithium (Li), sodium (Na), magnesium (Mg), zinc (Zn), aluminum (Al), and combinations thereof.

[0100] Wherein a can be an integer in the range of 1 to 5.

[0101] Here, b may be a value obtained by subtracting the oxidation number of M from a (the oxidation number of aM).

[0102] Non-limiting examples of Reaction Formula 1 may be at least one of the following Reaction Formulas 1-1 to 1-5.

[0103] Reaction formula 1-1:

[0104] Zn(s)+4OH - (aq)→Zn(OH) 4 2- (aq)+2e -

[0105] Reaction 1-2:

[0106] Li(s)+OH - (aq)→LiOH(aq)+e -

[0107] Reaction 1-3:

[0108] Na(s)+OH - (aq)→NaOH(aq)+e -

[0109] Reaction 1-4:

[0110] Mg(s)+2OH - (aq)→Mg(OH) 2 (aq)+2e -

[0111] Reaction 1-5:

[0112] Zn(s)+3OH - (aq)→Zn(OH) 2 -(aq)+3e -

[0113] The alkaline cation K of the third electrolyte 32 + Or Na + The alkaline cations move to the discharge unit 10 through the first ion exchange membrane 40, where they react with the bicarbonate ions (HCO 3 - ) to produce alkaline bicarbonate. As described above, the alkaline bicarbonate can be separated and recovered from the first electrolyte circulation unit 200.

[0114] The electrons generated according to Reaction Formula 1 are transferred to the reduction electrode 13 through the conductor, and a reaction represented by the following Reaction Formula 2 may occur at the reduction electrode 13 .

[0115] Reaction 2:

[0116] 2H + (aq)+2e - →H 2 (g)

[0117] As described above, the hydrogen generated according to Reaction Formula 2 may be separated and recovered from the first electrolyte circulation unit 200 .

[0118] When the metal battery 100 is charged, M(OH) generated in reaction formula 1 a b- (aq) reacts with the electrons that have migrated from the oxidation electrode 23 to the metal electrode 33, thereby being reduced to M(s) by the reaction of the following reaction formula 3.

[0119] Reaction 3:

[0120] M(OH) a b- (aq)+(ab)e - →M(s)+aOH - (aq)

[0121] In Reaction Formula 3, M, a and b are the same as those in Reaction Formula 1.

[0122] A non-limiting example of Reaction Formula 3 may be at least one of the following Reaction Formulas 3-1 to 3-5.

[0123] Reaction 3-1:

[0124] Zn(OH) 4 2- (aq)+2e - →Zn(s)+4OH - (aq)

[0125] Reaction 3-2:

[0126] LiOH(aq)+e - →Li(s)+OH - (aq)

[0127] Reaction 3-3:

[0128] NaOH(aq)+e - →Na(s)+OH - (aq)

[0129] Reaction 3-4:

[0130] Mg(OH) 2 (aq)+2e - →Mg(s)+2OH - (aq)

[0131] Reaction 3-5:

[0132] Al(OH) 3 (aq)+3e - →Al(s)+3OH - (aq)

[0133] Electrons are generated by the following reaction formula 4 occurring at the oxidation electrode 23 .

[0134] Reaction 4:

[0135] 4OH - (aq)→O 2 (g)+2H 2 O(l)+4e -

[0136] As the hydroxide ions are consumed, the alkaline cations K contained in the second electrolyte 22 are + Or Na + The ion may migrate to the electrode unit 30 through the second ion exchange membrane 50 .

[0137] The third electrolyte 32 of the electrode unit 30 may circulate through the third electrolyte circulation unit 500 for ionization and reduction control of the metal electrode 33 during charge and discharge of the metal battery.

[0138] Figure 3 A hydrogen generation and carbon dioxide storage system according to a second embodiment of the present invention is shown. Figure 3 The second embodiment of the system shown in FIG. 1 is characterized in that the first ion exchange membrane 40 and the second ion exchange membrane 50 are a cation exchange membrane and an anion exchange membrane, respectively.

[0139] 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, repeated descriptions about the same components will be omitted.

[0140] The first ion exchange membrane 40 may include a cation exchange membrane. The cation exchange membrane may be made of a cation conductive material. The type of cation conductive material is not particularly limited. Examples of cation conductive materials include perfluorosulfonic acid-based polymers such as Nafion, ion transport materials such as Nasicon, and the like.

[0141] The first ion exchange membrane 40 may allow cations to move between the first space 11 and the third space 31 , but prevent movement of the first electrolyte 12 and the third electrolyte 32 .

[0142] The second ion exchange membrane 50 may include an anion exchange membrane. The anion exchange membrane may be made of an anion conductive material. The anion conductive material is not particularly limited. For example, the anion conductive material includes at least one selected from the group consisting of poly(terphenyl), 1,4-diazabicyclo[2,2,2]octane-poly(ether sulfone), poly(arylpiperidinium), poly(phenylene oxide)-block-poly(vinylbenzyltrimethylammonium) and combinations thereof.

[0143] The second ion exchange membrane 50 may allow anions to move between the second space 21 and the third space 31 , but prevent movement of the second electrolyte 22 and the third electrolyte 32 .

[0144] During a discharge operation of the metal battery 100 , the metal electrode 33 of the electrode unit 30 is ionized by the third electrolyte 32 , and a reaction represented by the following Reaction Formula 1 may occur.

[0145] Reaction 1:

[0146] M(s)+aOH - (aq)→M(OH) a b- (aq)+(ab)e -

[0147] In Reaction Formula 1, M may include at least one selected from the group consisting of lithium (Li), sodium (Na), magnesium (Mg), zinc (Zn), aluminum (Al), and combinations thereof.

[0148] Wherein a can be an integer in the range of 1 to 5.

[0149] Here, b may be a value obtained by subtracting the oxidation number of M from a (the oxidation number of aM).

[0150] Non-limiting examples of Reaction Formula 1 may be at least one of the above Reaction Formulas 1-1 to 1-5.

[0151] The alkaline cation K of the third electrolyte 32 + Or Na + The alkaline cations move to the discharge unit 10 through the first ion exchange membrane 40, where they react with the bicarbonate ions (HCO 3 - ) to produce alkaline bicarbonate. As described above, the alkaline bicarbonate can be separated and recovered from the first electrolyte circulation unit 200.

[0152] The electrons generated according to Reaction Formula 1 are transferred to the reduction electrode 13 through the conductor, and a reaction represented by the following Reaction Formula 2 may occur at the reduction electrode 13 .

[0153] Reaction 2:

[0154] 2H + (aq)+2e - →H 2 (g)

[0155] As described above, the hydrogen generated according to Reaction Formula 2 may be separated and recovered from the first electrolyte circulation unit 200 .

[0156] When the metal battery 100 is charged, M(OH) generated in reaction formula 1 a b- (aq) reacts with the electrons that have migrated from the oxidation electrode 23 to the metal electrode 33, thereby being reduced to M(s) by the reaction of the following reaction formula 3.

[0157] Reaction 3:

[0158] M(OH) a b- (aq)+(ab)e - →M(s)+aOH - (aq)

[0159] In Reaction Formula 3, M, a and b are the same as those in Reaction Formula 1.

[0160] A non-limiting example of Reaction Formula 3 may be at least one of the above Reaction Formulas 3-1 to 3-5.

[0161] The hydroxide ions may migrate to the charging unit 20 through the second ion exchange membrane 50. A reaction represented by Reaction Formula 4 may occur at the oxidation electrode 23.

[0162] Reaction 4:

[0163] 4OH - (aq)→O 2 (g)+2H 2 O(l)+4e -

[0164] The electrons migrate to the metal electrode 33 via the conductor connected to the oxidation electrode 23 , and react according to Reaction Formula 3.

[0165] The third electrolyte 32 of the electrode unit 30 is consumed because the alkaline cation K + Or Na + The ions and hydroxide ions move to the discharge unit 10 and the charge unit 20 through the first ion exchange membrane 40 and the second ion exchange membrane 50, respectively. Therefore, the third electrolyte circulation unit 400 can replenish the third electrolyte with fresh water from the outside.

[0166] Figure 4A metal battery according to an embodiment of the present invention is shown. The metal battery 100 may include a discharge unit 10, a charge unit 20, an electrode unit 30, a first ion exchange membrane 40 interposed between the discharge unit 10 and the electrode unit 30, and a second ion exchange membrane 50 interposed between the charge unit 20 and the electrode unit 30.

[0167] The discharge cell 10 may include a first body plate 14 having a plate shape, a reduction electrode collector 15 disposed on a first surface of the first body plate 14 and having a sheet shape, and a first separator 16 having a frame shape and inserted between the reduction electrode collector 15 and the first ion exchange membrane 40 to form a first space 11.

[0168] The reduction electrode 13 may be disposed on a first surface of the reduction electrode current collector 15 .

[0169] Figure 5A The first separator 16 is shown. The first separator 16 may include a first electrolyte inflow portion 16a formed as a first portion passing through a flank thereof and configured to enable communication between the first space 11 and the external environment; and a first electrolyte outflow portion 16b formed as a second portion passing through a 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.

[0170] The charging unit 20 may include: a second main body plate 24 having a plate shape, an oxidation electrode collector 25 disposed on a first surface of the second main body plate 24 and having a sheet shape, and a second separator 26 having a frame shape and inserted between the oxidation electrode collector 25 and the second ion exchange membrane 50 to form a second space 21.

[0171] The oxidation electrode 23 may be disposed on a first surface of the oxidation electrode current collector 25 .

[0172] Figure 5B The second separator 26 is shown. The second separator 26 may include a second electrolyte inflow portion 26a formed as a first portion passing through a side thereof and configured to enable communication between the second space 21 and the external environment; and a second electrolyte outflow portion 26b formed as a second portion passing through a side 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.

[0173] The electrode unit 30 may include a sheet-shaped metal electrode collector 34 , a third separator 35 interposed between the metal electrode collector 34 and the first ion exchange membrane 40 , and a fourth separator 36 interposed between the metal electrode collector 34 and the second ion exchange membrane 50 .

[0174] The third partition 35 and the fourth partition 36 may form a third space 31 .

[0175] The metal electrodes 33 may be disposed on both surfaces of the metal electrode current collector 34 .

[0176] Figure 5C The third separator 35 is shown. The third separator 35 may include a third electrolyte inflow portion 35a formed as a first portion through a side thereof and configured to enable communication between the third space 31 and the external environment; and a third electrolyte outflow portion 35b formed as a second portion through a side thereof and configured to enable communication between the third space 31 and the external environment, the second portion being spaced apart from the first portion.

[0177] Figure 5D The fourth separator 36 is shown. The fourth separator 36 may include a third electrolyte inflow portion 35a formed as a first portion through a side thereof and configured to enable communication between the third space 31 and the external environment; and a third electrolyte outflow portion 35b formed as a second portion through a side thereof and configured to enable communication between the third space 31 and the external environment, the second portion being spaced apart from the first portion.

[0178] Other forms of the present invention will be described in more detail with reference to the embodiments described below. The embodiments described below are only used to help understand the present invention, and the scope of the present invention is not limited thereto.

[0179] Example 1

[0180] Preparation Figure 3 The metal battery shown. A cation exchange membrane is used as the first ion exchange membrane, and an anion exchange membrane is used as the second ion exchange membrane. The reduction electrode is platinum on a carbon support (Pt / C), the oxidation electrode is nickel foam, and the metal electrode is zinc (Zn). The first electrolyte is a 3M KHCO 3 The second and third electrolytes are aqueous solutions containing 6M KOH.

[0181] Example 2

[0182] Preparation Figure 2 The metal battery shown. The first ion exchange membrane and the second ion exchange membrane are cation exchange membranes. The rest of the structure is the same as that of Example 1.

[0183] Comparative Example

[0184] Preparation Figure 1 Conventional metal battery shown. The ion exchange membrane is a cation exchange membrane. The first metal is zinc (Zn) and the second metal is platinum supported on a carbon support (Pt / C), which is applied to nickel foam.

[0185] The first electrolyte is an aqueous solution containing 6M KOH, and the second electrolyte is an aqueous solution containing 3M KHCO 3 of aqueous solution.

[0186] Figure 6 The performance comparison results between the metal battery of Example 1 and the metal battery of the comparative example are shown. The left side of the figure shows the performance of the metal battery of the comparative example, and the right side of the figure shows the performance of the metal battery of Example 1. In the case of the comparative example, the voltage increases and the operating state becomes unstable during the charge and discharge cycle. These phenomena are caused by the corrosion of the carbon support. The metal battery of Example 1 has a higher charging efficiency than the metal battery of the comparative example because the voltage is about 1.1V lower. In addition, it is confirmed that the charging and discharging of the battery of Example 1 is stably performed compared to the battery of the comparative example.

[0187] Figure 7 The results of measuring the performance of the metal battery of Example 2 are shown. The battery of Example 2 showed the same performance as that of the battery of Example 1, and the voltage during charging was about 2.1 V. It was confirmed that the battery of Example 2 was stably charged and discharged.

[0188] Although the embodiments and experimental examples according to the present invention have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as defined in the accompanying claims.

Claims

1. A metal battery, include: an electrode unit comprising a metal electrode; a discharge unit located at a first side of the electrode unit; a charging unit located at a second side of the electrode unit; a first ion exchange membrane, which is located between the electrode unit and the discharge unit; and a second ion exchange membrane located between the electrode unit and the charging unit, The discharge unit includes a first space of a predetermined size, a first electrolyte contained in the first space, and a reduction electrode at least partially immersed in the first electrolyte. wherein the charging unit comprises a second space of a predetermined size, a second electrolyte contained in the second space, and an oxidation electrode at least partially immersed in the second electrolyte, and The electrode unit includes a third space of a predetermined size, a third electrolyte contained in the third space, and the metal electrode at least partially immersed in the third electrolyte.

2. The metal battery according to claim 1, in, The metal electrode includes at least one selected from the group consisting of lithium (Li), sodium (Na), magnesium (Mg), zinc (Zn), aluminum (Al), and combinations thereof.

3. The metal battery according to claim 1, in, The reduction electrode includes a support and a catalytic metal supported on the support.

4. The metal battery according to claim 1, in, The oxidation electrode comprises nickel foam.

5. The metal battery according to claim 1, in, The discharge unit further includes: A first main body plate in a plate shape; a reduction electrode current collector which is located on the first surface of the first body plate and is in a sheet shape; and a first separator having a frame shape and located between the reduction electrode current collector and the first ion exchange membrane to form the first space, Wherein, the reduction electrode is located on the first surface of the reduction electrode current collector.

6. The metal battery according to claim 5, in, The first spacer comprises: A first electrolyte inflow portion extending through a first portion of a side of the first separator and configured to enable communication between the first space and an external environment; and A first electrolyte outflow portion extends through a second portion of the side of the first separator and is configured to enable communication between the first space and an external environment, the second portion being spaced apart from the first portion.

7. The metal battery according to claim 1, in, The charging unit further includes: A second main body plate in the form of a plate; an oxidation electrode current collector which is located on the first surface of the second body plate and is in a sheet shape; and a second separator having a frame shape and located between the oxidation electrode current collector and the second ion exchange membrane to form the second space, Wherein, the oxidation electrode is located on the first surface of the oxidation electrode current collector.

8. The metal battery according to claim 7, in, The second spacer comprises: A second electrolyte inflow portion extending through a first portion of a side of the second separator and configured to enable communication between the second space and an external environment; and A second electrolyte outflow portion extends through a second portion of the side of the second separator and is configured to enable communication between the second space and an external environment, the second portion being spaced apart from the first portion.

9. The metal battery according to claim 1, in, The electrode comprises: A sheet-shaped metal electrode current collector; a third separator located between the metal electrode current collector and the first ion exchange membrane; and a fourth separator, which is located 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 located on two surfaces of the metal electrode current collector.

10. The metal battery according to claim 9, in, At least one of the third spacer and the fourth spacer comprises: A third electrolyte inflow portion extending through a first portion of a side of the corresponding separator and configured to enable communication between the third space and an external environment; and A third electrolyte outflow portion extends through a second portion of a side of the corresponding separator and is configured to enable communication between the third space and an external environment, the first portion being spaced apart from the second portion.

11. The metal battery according to claim 1, in, The first space and the third space are separated from each other by the first ion exchange membrane, and 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, in, The first ion exchange membrane comprises a cation exchange membrane, and The second ion exchange membrane includes a cation exchange membrane.

13. The metal battery according to claim 1, in, The first ion exchange membrane comprises a cation exchange membrane, and The second ion exchange membrane includes an anion exchange membrane.

14. The metal battery according to claim 1, in, The first electrolyte includes water and bicarbonate.

15. The metal battery according to claim 1, in, The second electrolyte includes at least one selected from the group consisting of potassium hydroxide (KOH), sodium hydroxide (NaOH), and a combination thereof.

16. The metal battery according to claim 1, in, The third electrolyte includes at least one selected from the group consisting of potassium hydroxide (KOH), sodium hydroxide (NaOH), and a combination thereof.

17. The metal battery according to claim 1, in, During discharge, a reaction represented by reaction formula 1 occurs in the electrode unit, and a reaction represented by reaction formula 2 occurs in the discharge unit, wherein reaction formula 1 is: M(s)+aOH - (aq)→M(OH) a b- (aq)+(a-b)e - , Wherein, in 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 ranging from 1 to 4, b is a minus the oxidation number of M; and Among them, reaction formula 2 is: 2H + (aq)+2e - →H 2 (g).

18. The metal battery according to claim 1, in, During charging, a reaction represented by reaction formula 3 occurs in the electrode unit, and a reaction represented by reaction formula 4 occurs in the charging unit, wherein reaction formula 3 is: M(OH) a b- (aq)+(a-b)e - →M(s)+aOH - (aq), Wherein, in 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 ranging from 1 to 4, b is a minus the oxidation number of M; and Among them, reaction formula 4 is: 4OH - (aq)→O 2 (g)+2H 2 O(l)+4e - .

19. A hydrogen generation and carbon dioxide storage system, include: The metal battery according to claim 1; a first electrolyte circulation unit connected to the metal battery to receive the first electrolyte discharged from the discharge unit, the first electrolyte circulation unit being configured to separate hydrogen gas contained in the first electrolyte and supply the first electrolyte to the discharge unit; a second electrolyte circulation unit connected to the metal battery to receive the second electrolyte discharged from the charging unit, the second electrolyte circulation unit being configured to separate oxygen contained in the second electrolyte and supply the second electrolyte to the charging unit; and A third electrolyte circulation unit is connected to the metal battery to receive the third electrolyte discharged from the electrode unit and supply the third electrolyte to the electrode unit.

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