Carbon dioxide adsorption battery and charge / discharge device

Abstract

One aspect of the present invention is a carbon dioxide adsorption battery comprising: a positive electrode; a negative electrode; an electrolyte layer disposed between the positive electrode and the negative electrode; and a flow path connected to the negative electrode. The electrolyte layer includes an electrolytic solution capable of dissolving carbon dioxide, the negative electrode is an electrode capable of transmitting gas, the positive electrode includes a porous electrode, and the specific surface area of the porous electrode is 100-3000 m2 / g in terms of BET specific surface area and greater than the specific surface area of the negative electrode.

Description

Carbon dioxide adsorption battery and charging / discharging device

[0001] The present invention relates to a carbon dioxide adsorption battery and a charge / discharge device.

[0002] Carbon dioxide is not only a widely distributed substance on Earth, accounting for approximately 0.04% of the atmosphere, but is also widely used in industry. Examples of uses of carbon dioxide include foaming gas for carbonated beverages, bath additives, and fire extinguishing agents, dry ice used for cooling, and emergency air refills for bicycle tires. Carbon dioxide can also be used as an extraction solvent for extracting caffeine and other substances by bringing it to a supercritical state. Carbon dioxide is also used in lasers used in industrial processing and carbon dioxide lasers used in medical laser scalpels. Furthermore, carbon dioxide is sometimes used as a compressor refrigerant instead of a fluorocarbon-based refrigerant. Carbon dioxide is also used in agriculture, for example, for forcing strawberries and for carbon dioxide fertilization to accelerate the growth of plants such as aquatic plants in ornamental aquariums. Carbon dioxide is also used in controlled atmosphere (CA) storage of fresh agricultural produce.

[0003] As described above, carbon dioxide is used in various fields, and therefore, there is a demand for a method of obtaining carbon dioxide by, for example, separating carbon dioxide from a gas containing carbon dioxide, such as air. Carbon dioxide is also said to be a causative substance of global warming. For this reason, there is a demand for separating carbon dioxide from a gas containing carbon dioxide and utilizing the carbon dioxide. In order to utilize carbon dioxide, there is a demand for the development of, for example, a method of separating carbon dioxide from a gas containing carbon dioxide, an apparatus for adsorbing and separating carbon dioxide, and an apparatus for utilizing carbon dioxide.

[0004] Various methods have been proposed for separating carbon dioxide from a mixed gas containing oxygen and carbon dioxide, such as air. Examples of such separation methods include a method in which a carbon dioxide adsorbent is used to adsorb carbon dioxide in the air, and then the carbon dioxide adsorbed by the adsorbent is desorbed, thereby separating carbon dioxide from the air. Examples of adsorbents that adsorb carbon dioxide include activated carbon, amine solvents, and aqueous potassium carbonate solutions. More specifically, examples of carbon dioxide separation methods using an adsorbent include pressure swing adsorption (PSA), in which carbon dioxide is adsorbed onto an adsorbent under high pressure, and then the pressure is reduced to desorb the carbon dioxide from the adsorbent. Examples of adsorbents used in separating carbon dioxide using this PSA method include the adsorbents described in Patent Document 1.

[0005] Patent Document 1 describes a carbon dioxide adsorbent comprising a composition in which 2 to 80 equivalent percent of the sodium ions in a sodium-containing aluminosilicate have been ion-exchanged with barium ions. Patent Document 1 discloses that it is possible to provide an adsorbent that has a high selectivity for carbon dioxide and a large absorption capacity even under conditions of high moisture content. Patent Document 1 also discloses that this adsorbent can be suitably used for separating and concentrating carbon dioxide by a PSA method.

[0006] Examples of devices for adsorbing and separating carbon dioxide include an acidic gas adsorption / desorption device described in Patent Document 2 and a carbon dioxide separation device described in Patent Document 3.

[0007] Patent Document 2 describes an acidic gas adsorption / desorption device having an acidic gas adsorption / desorption layer including a compound and a substrate capable of adsorbing and desorbing acidic gases such as carbon dioxide by oxidation and reduction, and a pair of electrodes sandwiching the acidic gas adsorption / desorption layer. Patent Document 2 discloses that acidic gases can be adsorbed and desorbed in a solid state.

[0008] Patent Document 3 describes a carbon dioxide separator that includes an electrolyte layer, a pair of electrodes sandwiching the electrolyte layer and provided on the electrolyte layer, and a voltage application unit that applies a voltage between the pair of electrodes, wherein each of the pair of electrodes is permeable to gas, and the electrolyte layer contains an electrolytic solution that can dissolve carbon dioxide and a redox compound having an N-oxy radical group in its molecule. Patent Document 3 discloses that it is possible to provide a carbon dioxide separator that can easily separate carbon dioxide from a gas that contains carbon dioxide.

[0009] Examples of devices that utilize carbon dioxide include the batteries described in Non-Patent Documents 1 and 2.

[0010] Non-Patent Document 1 proposes a method for utilizing carbon dioxide, in which a battery is charged while absorbing carbon dioxide.

[0011] Non-Patent Document 2 proposes a carbon dioxide rechargeable battery incorporating a redox system. Specifically, the proposed carbon dioxide rechargeable battery uses poly-1,4-anthraquinone and polyvinylferrocene in the negative and positive electrodes, respectively.

[0012] Examples of devices that utilize carbon dioxide include secondary batteries that not only utilize carbon dioxide but also can concentrate carbon dioxide by adsorbing and desorbing carbon dioxide. Examples of such secondary batteries include the carbon dioxide adsorption battery described in Patent Document 4.

[0013] Patent Document 4 describes a carbon dioxide adsorption battery comprising a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and an electrolyte layer disposed between the positive electrode and the separator and between the negative electrode and the separator, wherein the positive electrode is a gas-permeable electrode, the electrolyte layer contains an electrolyte solution capable of dissolving carbon dioxide and a redox compound having an N-oxy radical group in its molecule, and the separator inhibits permeation of the redox compound and is permeable to the electrolyte. Patent Document 4 discloses that it is possible to provide a carbon dioxide adsorption battery that can be charged while easily adsorbing carbon dioxide from a gas containing carbon dioxide.

[0014] In a device capable of utilizing carbon dioxide, there is a demand for a device that can utilize carbon dioxide more effectively and that can separate carbon dioxide from a gas containing carbon dioxide in a short time while reducing power consumption, etc. In other words, there is a demand for such a device that can utilize carbon dioxide to be able to adsorb and desorb carbon dioxide in a short time even at a low voltage.

[0015] Japanese Patent Application Laid-Open No. 7-39752 Japanese Patent Application Laid-Open No. 2015-36128 Japanese Patent Application Laid-Open No. 2018-1131 International Publication No. 2022 / 185903

[0016] Aliza Khurram et al. , “Tailoring the Discharge Reaction in Li-CO2 Batteries through Corporation of CO2 Capture Chemistry”, Joule 2, 2649-2666, December 19, 2018 Sahag Voskian et al. , “Faradaiic electro-swing reactive adsorption for CO2 Capture”, Energy & Environmental Science, 2019, 12, 3530-3547

[0017] The present invention has been made in consideration of the above circumstances, and aims to provide a carbon dioxide adsorption battery that can adsorb carbon dioxide from a carbon dioxide-containing gas while charging and desorb the carbon dioxide during discharge in a short time even at a low voltage. Another aim of the present invention is to provide a charge / discharge device that includes the carbon dioxide adsorption battery.

[0018] One aspect of the present invention provides a battery comprising a positive electrode, a negative electrode, an electrolyte layer disposed between the positive electrode and the negative electrode, and a flow path connected to the negative electrode, wherein the electrolyte layer contains an electrolyte solution capable of dissolving carbon dioxide, the negative electrode is an electrode that is permeable to gas, and the positive electrode includes a porous electrode, and the porous electrode has a specific surface area of ​​100 to 3000 m in terms of BET specific surface area. ２ / g and is larger than the specific surface area of ​​the negative electrode.

[0019] These and other objects, features and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

[0020] FIG. 1 is a schematic cross-sectional view showing an example of the configuration of a carbon dioxide adsorption battery according to an embodiment of the present invention during charging. FIG. 2 is a schematic cross-sectional view showing an example of the configuration of a carbon dioxide adsorption battery according to an embodiment of the present invention during discharging. FIG. 3 is a schematic cross-sectional view showing another example of the configuration of a carbon dioxide adsorption battery according to an embodiment of the present invention during charging. FIG. 4 is a schematic cross-sectional view showing another example of the configuration of a carbon dioxide adsorption battery according to an embodiment of the present invention during discharging. FIG. 5 is a schematic cross-sectional view showing another example of the configuration of a carbon dioxide adsorption battery according to an embodiment of the present invention during charging. FIG. 6 is a schematic cross-sectional view showing another example of the configuration of a carbon dioxide adsorption battery according to an embodiment of the present invention during discharging. FIG. 7 is a schematic cross-sectional view showing an example of the configuration of a charge / discharge device according to an embodiment of the present invention.

[0021] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these.

[0022] [Carbon Dioxide Adsorption Battery] As shown in Figures 1 and 2, the carbon dioxide adsorption battery 10 according to the first embodiment of the present invention includes a positive electrode 11, a negative electrode 12, an electrolyte layer 14 disposed between the positive electrode 11 and the negative electrode 12, and a flow path 15 connected to the negative electrode 12. In the carbon dioxide adsorption battery 10, it is only necessary that the positive electrode 11 and the negative electrode 12 are not in direct contact with each other. For this reason, the carbon dioxide adsorption battery 10 does not need to include a separator, for example, because the electrolyte layer 14 is disposed between the positive electrode 11 and the negative electrode 12. However, it is preferable that the carbon dioxide adsorption battery 10 include a separator. Specifically, it is preferable that the carbon dioxide adsorption battery 10 further includes a separator 13 disposed between the positive electrode 11 and the electrolyte layer 14, for example, as shown in Figures 1 and 2. That is, in the carbon dioxide adsorption battery 10, the positive electrode 11 is disposed on one surface of the electrolyte layer 14 (and the separator 13), and the negative electrode 12 is disposed on the other surface of the electrolyte layer 14 (and the separator 13). The electrolyte layer 14 contains an electrolyte solution capable of dissolving carbon dioxide. The separator 13 can prevent direct contact between the positive electrode 11 and the negative electrode 12. The separator 13 is also permeable to an electrolyte solution, for example, the electrolyte solution contained in the electrolyte layer 14. The separator 13 is preferably one that is easily permeable to an electrolyte solution and has a density and strength that can prevent contact between the positive electrode 11 and the negative electrode 12. The negative electrode 12 is a gas-permeable electrode. Specifically, the negative electrode 12 can allow gas flowing through the flow path 15 to pass through and come into contact with the electrolyte layer 14. The positive electrode 11 includes a porous electrode 11a. The porous electrode 11a has a specific surface area of ​​100 to 3000 m2 in terms of BET specific surface area. ２ / g, which is higher than the specific surface area of ​​the negative electrode 12. The positive electrode 11 may include the porous electrode 11a. For example, the positive electrode 11 may be an electrode made of the porous electrode 11a, or an electrode including the porous electrode 11a on the electrolyte layer 14 side. An example of an electrode including the porous electrode 11a on the electrolyte layer 14 side is an electrode including a current collector 11b and the porous electrode 11a disposed on the surface of the current collector 11b facing the electrolyte layer 14 (and the separator 13), as shown in FIGS. 1 and 2 . The porous electrode 11a may also include, for example, the electrolyte solution contained in the electrolyte layer 14. In the case where the separator 13 is provided, as in the carbon dioxide adsorption battery 10, an example of the electrolyte solution is an electrolyte solution obtained by permeating the electrolyte solution contained in the electrolyte layer 14 through the separator 13. While the porous electrode 11a preferably includes an electrolyte solution as described above, it is not necessary for the porous electrode 11a to include a redox compound, such as a compound capable of adsorbing and desorbing carbon dioxide through an electrochemical reaction. For this reason, the electrolyte solution does not need to contain a redox compound. Even if it does contain a redox compound, the content of the redox compound relative to the electrolyte solution may be 40% by mass or less (i.e., 0 to 40% by mass), or 30% by mass or less (i.e., 0 to 30% by mass). However, it is preferably 20% by mass or less (i.e., 0 to 20% by mass), more preferably 10% by mass or less (i.e., 0 to 10% by mass), even more preferably 5% by mass or less (i.e., 0 to 5% by mass), and even more preferably 0% by mass. The positive electrode 11 is disposed on one side of the electrolyte layer 14 (and the separator 13). Specifically, it is preferable that the porous electrode 11a is disposed in contact with the separator 13. Furthermore, when the separator 13 is provided, as in the carbon dioxide adsorption battery 10, for example, the electrolyte layer 14 is preferably disposed in contact with the separator 13. The flow path 15 is not particularly limited as long as it is a flow path that allows gas to flow. Furthermore, the flow path 15 may be provided with a valve 18 as necessary.It should be noted that the valves 18 shown in the figure are only those that are closed and restrict the flow of gas through the flow path 15. Specifically, the valves 18 are not shown in Fig. 1, but are shown in Fig. 2.

[0023] 1 and 2 are schematic cross-sectional views showing an example of the configuration of a carbon dioxide adsorption battery according to an embodiment of the present invention (the carbon dioxide adsorption battery 10), where FIG. 1 shows the carbon dioxide adsorption battery 10 during charging, and FIG. 2 shows the carbon dioxide adsorption battery 10 during discharging.

[0024] During charging of the carbon dioxide adsorption battery 10, as shown in FIG. 1 , a voltage is applied between the positive electrode 11 and the negative electrode 12 (between a pair of electrodes consisting of the positive electrode 11 and the negative electrode 12) so that the potential of the negative electrode 12 is lower than the potential of the positive electrode 11. Specifically, this voltage is a voltage that causes carbon dioxide to be adsorbed to the negative electrode. This voltage is considered to be, for example, a voltage that causes carbon dioxide to be adsorbed to the negative electrode through an electrochemical reaction, as described below. The charging of the carbon dioxide adsorption battery 10 is not particularly limited as long as a voltage can be applied as described above. Examples of charging of the carbon dioxide adsorption battery 10 include charging by providing a voltage application unit 16 that applies a voltage between the positive electrode 11 and the negative electrode 12 (between a pair of electrodes consisting of the positive electrode 11 and the negative electrode 12) so that the potential of the negative electrode 12 is lower than the potential of the positive electrode 11, as shown in FIG. 1 . The discharge of the carbon dioxide adsorption battery 10 is not particularly limited, and examples thereof include discharge by electrically connecting the positive electrode 11 and the negative electrode 12. Examples of discharge of the carbon dioxide adsorption battery 10 include discharge by providing a resistor 17 between a pair of electrodes consisting of the positive electrode 11 and the negative electrode 12, as shown in FIG.

[0025] As shown in FIG. 1 , in the carbon dioxide adsorption battery 10, when a gas containing carbon dioxide and oxygen is first circulated through the flow path 15, the gas contacts the negative electrode 12, and at least a portion of the gas permeates the negative electrode 12. As the gas permeates the negative electrode 12, the gas that has permeated the negative electrode 12 contacts the negative electrode 12 side of the electrolyte layer 14 and comes into contact with the electrolytic solution contained in the electrolyte layer 14. Because the electrolytic solution contained in the electrolyte layer 14 is capable of dissolving carbon dioxide, the carbon dioxide contained in the gas that has contacted the electrolyte layer 14 is dissolved in the electrolytic solution contained in the electrolyte layer 14. Furthermore, if the electrolytic solution contained in the electrolyte layer 14 has also migrated to the negative electrode 12, the gas also contacts the electrolytic solution that has migrated to the negative electrode 12 as it permeates the negative electrode 12, and the carbon dioxide contained in the gas is also dissolved in this electrolytic solution. In this way, if the gas present around the negative electrode 12 contains carbon dioxide, the carbon dioxide contained in the gas is dissolved in the electrolytic solution. The gas is not particularly limited as long as it contains carbon dioxide and oxygen, and examples thereof include gases containing carbon dioxide, oxygen, and nitrogen, more specifically air, etc. Furthermore, when the gas contains oxygen, this oxygen comes into contact not only with the negative electrode 12 but also with the negative electrode 12 side of the electrolyte layer 14.

[0026] In the carbon dioxide adsorption battery 10, when a voltage is applied between the positive electrode 11 and the negative electrode 12 while a gas containing carbon dioxide and oxygen is circulating through a flow path 15 connected to the negative electrode 12, the carbon dioxide is adsorbed onto the negative electrode 12. The mechanism by which carbon dioxide is adsorbed is not clear, but is thought to be the following mechanism. When a voltage is applied between the positive electrode 11 and the negative electrode 12 and electrons flow into the negative electrode 12, oxygen in contact with the negative electrode 12 and the negative electrode 12 side of the electrolyte layer 14 is reduced to a reduced form such as a superoxide radical, which is then bound to the negative electrode. It is thought that carbon dioxide present around the negative electrode 12 or dissolved in the electrolyte solution binds to the reduced form such as a superoxide radical bound to the negative electrode, causing the carbon dioxide to be adsorbed onto the negative electrode 12.

[0027] When a voltage is applied between the positive electrode 11 and the negative electrode 12 and electrons flow into the negative electrode 12, carbon dioxide is adsorbed to the negative electrode 12, and cations derived from the electrolyte are also adsorbed to the negative electrode 12. When a negative electrode with a small surface area, specifically a negative electrode with a specific surface area smaller than that of the porous electrode 11a, is used as the negative electrode 12, carbon dioxide is more likely to be adsorbed to the negative electrode. This is thought to be because cation adsorption tends to occur more easily when the specific surface area of ​​the negative electrode 12 is high and less likely to occur when the specific surface area of ​​the negative electrode 12 is low. Therefore, when the specific surface area of ​​the negative electrode 12 is low, carbon dioxide adsorption to the negative electrode 12 tends to occur more easily than cation adsorption.

[0028] For these reasons, when a voltage that reduces oxygen in contact with the negative electrode 12 is applied between the positive electrode 11 and the negative electrode 12, the carbon dioxide adsorption battery 10 enters a state in which carbon dioxide is adsorbed to the negative electrode through an electrochemical reaction, and the carbon dioxide is adsorbed to the negative electrode 12. When carbon dioxide is adsorbed to the negative electrode 12 in this manner, the carbon dioxide adsorption battery 10 enters a charged state. Furthermore, carbon dioxide that has come into contact with the negative electrode 12 or that has dissolved in the electrolyte is adsorbed to the negative electrode 12, accelerating the dissolution of carbon dioxide into the electrolyte. This promotes permeation of carbon dioxide through the negative electrode 12, and the carbon dioxide adsorption battery 10 favorably progresses to a charged state. For these reasons, as shown in FIG. 1 , in the carbon dioxide adsorption battery 10, when a gas containing carbon dioxide and oxygen is circulated through a flow path 15 connected to the negative electrode 12 and a voltage that reduces oxygen in contact with the negative electrode 12 is applied between the positive electrode 11 and the negative electrode 12, carbon dioxide is adsorbed and the battery can be charged. Furthermore, in the carbon dioxide adsorption battery 10, as described above, at least the electrolyte layer 14 is present between the positive electrode 11 and the negative electrode 12, and therefore, even if the application of voltage between the positive electrode 11 and the negative electrode 12 is stopped, the state in which carbon dioxide is adsorbed, i.e., the charged state, is suitably maintained as long as the positive electrode 11 and the negative electrode 12 are not electrically connected and discharged. Furthermore, as described above, the carbon dioxide adsorption battery 10 includes the separator 13 disposed between the positive electrode 11 and the electrolyte layer 14, and therefore, electrical contact between the positive electrode 11 and the negative electrode 12 can be further suppressed. Therefore, in the carbon dioxide adsorption battery 10, even if the application of voltage between the positive electrode 11 and the negative electrode 12 is stopped, the state in which carbon dioxide is adsorbed, i.e., the charged state, is suitably maintained.

[0029] 2 , when the positive electrode 11 and the negative electrode 12 are electrically connected and discharged, the state in which carbon dioxide is adsorbed to the negative electrode 12 by an electrochemical reaction is eliminated, and the carbon dioxide adsorbed to the negative electrode 12 is desorbed from the negative electrode 12. Therefore, in the carbon dioxide adsorption battery 10, carbon dioxide is released from the negative electrode 12 into a flow path 15 connected to the negative electrode 12 during discharge. The gas released from the carbon dioxide adsorption battery 10 during discharge is supplemented with carbon dioxide adsorbed to the negative electrode 12 in the carbon dioxide adsorption battery 10 during charge, thereby increasing the carbon dioxide concentration and enabling carbon dioxide to be concentrated. Note that, because carbon dioxide is released into the flow path 15, it is preferable that the valve 18 upstream of the flow path 15 be closed to prevent backflow of carbon dioxide.

[0030] For these reasons, the carbon dioxide adsorption battery 10 selectively adsorbs carbon dioxide from a gas containing carbon dioxide during charging, and releases the adsorbed carbon dioxide during discharging, thereby concentrating carbon dioxide.

[0031] The carbon dioxide adsorption battery 10 also operates by adsorption of the electrolyte solution by applying the voltage between the positive electrode 11 and the negative electrode 12. Specifically, when the voltage is applied between the positive electrode 11 and the negative electrode 12 and electrons are extracted from the positive electrode 11, anions derived from the electrolyte solution are adsorbed to the positive electrode 11. The carbon dioxide adsorption battery 10 also operates by adsorption of anions to the positive electrode 11 in this way. That is, the carbon dioxide adsorption battery 10 also performs charge compensation (specifically, charge compensation like a capacitor) without the electrochemical reaction in the positive electrode 11. This is thought to be because anion adsorption tends to occur more easily when the specific surface area of ​​the positive electrode 11 is high and less easily when the specific surface area of ​​the positive electrode 11 is low. In the carbon dioxide adsorption battery 10, a BET specific surface area of ​​100 to 3000 m is used. ２ / g, and the positive electrode 11 includes a porous electrode 11a having a larger specific surface area than the negative electrode, so the charge compensation can be performed effectively. The charge compensation here has lower resistance than when the electrochemical reaction is involved, which contributes to driving at a lower voltage (i.e., lower power consumption) than in conventional technology. As mentioned above, the negative electrode 12 also adsorbs cations derived from the electrolyte, but carbon dioxide adsorption occurs preferentially. Therefore, the negative electrode 12 is charged while adsorbing carbon dioxide along with the charge compensation.

[0032] From the above, the carbon dioxide adsorption battery 10 is a carbon dioxide adsorption battery that is charged when the voltage is applied between the positive electrode 11 and the negative electrode 12, and carbon dioxide is adsorbed to the negative electrode 12, and that is desorbed when the positive electrode 11 and the negative electrode 12 are electrically connected and the battery is discharged. Thus, the carbon dioxide adsorption battery 10 can provide a carbon dioxide adsorption battery that can be charged while adsorbing carbon dioxide from a gas containing carbon dioxide, and can desorb the carbon dioxide during discharge in a short time even at a low voltage.

[0033] (Positive Electrode) The positive electrode 11 may include the porous electrode 11a. For example, the positive electrode 11 may be an electrode consisting of the porous electrode 11a, or an electrode including the porous electrode 11a on the electrolyte layer 14 side. An example of an electrode including the porous electrode 11a on the electrolyte layer 14 side is an electrode including a current collector 11b and the porous electrode 11a disposed on the surface of the current collector 11b facing the electrolyte layer 14 (and the separator 13), as shown in FIGS. 1 and 2 . The positive electrode 11 may also include layers other than the porous electrode 11a and the current collector 11b for purposes such as maintaining strength. The porous electrode 11a also includes an electrolyte solution. Examples of the electrolyte solution include the electrolyte solution contained in the electrolyte layer 14, such as the electrolyte solution that has permeated the separator 13 from the electrolyte solution contained in the electrolyte layer 14.

[0034] The porous electrode 11a has a specific surface area of ​​100 to 3000 m2 in terms of BET specific surface area. ２ / g and is higher than the specific surface area of ​​the negative electrode 12. The specific surface area of ​​the porous electrode 11a is 100 m / g in terms of BET specific surface area. ２ / g or more, and ２ / g or more, and ２ The specific surface area of ​​the porous electrode 11a is preferably 3000 m / g or more in terms of BET specific surface area. ２ / g or less, and ２ / g or less, and ２ Therefore, the BET specific surface area of ​​the porous electrode 11a is preferably 100 to 3000 m / g or less. ２ / g, and 500 to 2500m ２ / g, and 800 to 2300m ２ / g is more preferable. When the BET specific surface area of ​​the porous electrode 11a is within the above range, charge compensation without the electrochemical reaction is preferably performed. This is thought to be because anions derived from the electrolyte are preferably adsorbed onto the porous electrode 11a provided in the positive electrode 11. Therefore, since the porous electrode 11a is porous such that the BET specific surface area is within the above range, a large amount of anions derived from the electrolyte is adsorbed, and therefore the electrode can be driven at a low voltage. The BET specific surface area is a specific surface area measured by the BET method and can be measured by a known method. Examples of methods for measuring the BET specific surface area include a method of measuring a nitrogen adsorption isotherm and calculating the BET specific surface area from the obtained adsorption isotherm, and more specifically, a method of measuring the specific surface area of ​​a powder (solid) by gas adsorption in accordance with JIS Z8830:2013, and the like.

[0035] The specific surface area of ​​the porous electrode 11a is higher than the specific surface area of ​​the negative electrode 12. The BET specific surface area of ​​the porous electrode 11a is greater than the BET specific surface area of ​​the negative electrode 12, preferably 10 to 3,000 times, more preferably 20 to 2,000 times, and even more preferably 30 to 1,000 times. That is, the ratio of the BET specific surface area of ​​the porous electrode 11a to the BET specific surface area of ​​the negative electrode 12 (BET specific surface area of ​​porous electrode 11a / BET specific surface area of ​​negative electrode 12) is greater than 1, preferably 10 to 3,000 times, more preferably 20 to 2,000 times, and even more preferably 30 to 1,000 times. When the ratio of the BET specific surface area of ​​the porous electrode 11a to the BET specific surface area of ​​the negative electrode 12 is within the above range, charge / discharge and carbon dioxide adsorption / desorption can be performed more efficiently. For example, charging / discharging and adsorption / desorption of carbon dioxide can be performed at a lower voltage or in a shorter time. This is thought to be because the adsorption of carbon dioxide occurs more preferentially than the adsorption of cations in the negative electrode 12, and the adsorption of anions occurs more favorably in the positive electrode 11. In addition, the difference between the BET specific surface area of ​​the porous electrode 11a and the BET specific surface area of ​​the negative electrode 12 (BET specific surface area of ​​the porous electrode 11a - BET specific surface area of ​​the negative electrode 12) is 100 to 3000 m ２ / g, and 500 to 2500m ２ It is more preferable that the SiO2 content is 1 / g.

[0036] The porous electrode 11a has a specific surface area of ​​100 to 3000 m2 in terms of BET specific surface area. ２ / g, which is larger than the specific surface area of ​​the negative electrode 12, allows the porous electrode 11a to suitably perform charge compensation without electrochemical reaction when the voltage is applied to the positive electrode 11. Examples of the porous electrode 11a include an electrode made of a conductive material capable of adsorbing anions derived from the electrolyte solution and passing a current. The porous electrode 11a is preferably a porous body that has conductivity sufficient to not inhibit electron transfer, can store charge, and has a large contact area with the electrolyte solution. Examples of the porous electrode 11a include electrodes made of the same material as the negative electrode 12. More specifically, examples of the porous electrode 11a include electrodes made of a porous conductive material and electrodes made of a porous body containing a conductive material. Examples of the porous conductive material include a porous body containing conductive fibers, a porous body containing carbon as a main component, and a porous body made of carbon. Examples of the carbon include carbonaceous materials such as graphite, carbon nanotubes, carbon black such as acetylene black, activated carbon such as activated carbon fiber, and carbon fibers. The carbon-containing porous body is preferably a cloth- or felt-like carbonaceous material, such as a cloth- or felt-like material containing the carbonaceous material and a resin. Examples of the resin include styrene-butadiene rubber and carboxymethyl cellulose. Examples of the porous body containing conductive fibers include woven fabrics containing conductive fibers, knitted fabrics containing conductive fibers, and braided fabrics containing conductive fibers. Examples of the conductive fibers include fibers coated with metal. Examples of the coating method include plating. Examples of the conductive fibers include plated fibers. The porous conductive materials may be used alone or in combination of two or more. That is, the porous electrode 11a may be an electrode composed of a single porous conductive material or a combination of two or more conductive materials.Examples of conductive materials contained in the porous body include metal fibers, conductive fibers, metal particles, conductive ceramics, graphite, carbon nanotubes, activated carbon such as activated carbon fibers, and carbonaceous materials such as carbon fibers. Examples of the metal fibers and metal particles include those containing copper and silver. The porous body containing the metal fibers may be a porous conductive material. Examples of the conductive material include graphite, carbon nanotubes, activated carbon, and carbon fibers. From the viewpoints of corrosion resistance and specific surface area, activated carbon such as activated carbon fibers is more preferable. The conductive materials may be used alone or in combination of two or more. Examples of the porous electrode 11a include carbon-based electrodes using activated carbon or carbon fibers, and electrodes with high porosity using needle-shaped conductive materials. Specific examples of the porous electrode 11a include carbon sheets, carbon cloth, and carbon paper. Among the above-mentioned electrodes, the porous electrode 11a is preferably an electrode made of a porous material containing at least one selected from the group consisting of conductive ceramics, graphite, carbon nanotubes, activated carbon, and carbon fibers. A positive electrode 11 including such a porous electrode 11a is considered to not only more suitably apply a voltage between the positive electrode 11 and the negative electrode 12, but also more suitably perform charge compensation without electrochemical reactions. Therefore, when the positive electrode 11 includes the porous electrode 11a, for example, when the porous electrode 11a is provided on the electrolyte layer 14 side, a carbon dioxide adsorption battery can be obtained that can efficiently adsorb carbon dioxide from a carbon dioxide-containing gas during charging and desorb the carbon dioxide during discharge, and can also be operated at a lower voltage (i.e., with lower power consumption).

[0037] The surface resistance of the porous electrode 11a is preferably as small as possible, for example, 1 kΩ / sq or less is preferable, and 200 Ω / sq or less is more preferable. Although the surface resistance of the porous electrode 11a is preferably as small as possible, in practice, the limit is 1 Ω / sq, and it is often approximately 10 Ω / sq or more. Therefore, the surface resistance of the porous electrode 11a is preferably 1 Ω / sq to 1 kΩ / sq, and more preferably 10 to 200 Ω / sq.

[0038] The thickness of the porous electrode 11a is not particularly limited, but is preferably a thickness that can adsorb anions derived from the electrolyte solution and suitably prevent leakage of the electrolyte solution. The thickness of the porous electrode 11a is, for example, preferably 20 μm to 10 mm, more preferably 50 μm to 5 mm. If the porous electrode 11a is too thin, the strength of the electrode tends to be insufficient.

[0039] As described above, the positive electrode 11 may include a current collector 11b. The current collector 11b is not particularly limited as long as it is made of a conductive material, and examples thereof include the same current collector as that included in the negative electrode 12. Examples of the current collector include those made of metals such as metal foil, mesh metal, punched metal, and expanded metal. Examples of metals that can be used as the current collector include stainless steel, iron, nickel, titanium, and copper.

[0040] The thickness of the positive electrode 11 is not particularly limited, but is preferably a thickness that can suitably prevent leakage of the electrolyte. The thickness of the positive electrode 11 is, for example, preferably 20 μm to 10 mm, and more preferably 50 μm to 5 mm.

[0041] In the positive electrode 11 including the current collector 11b, the porous electrode 11a and the current collector 11b are preferably integrated. The integration method is not particularly limited, and examples include methods similar to those used to integrate the porous body and current collector in the negative electrode 12. Specifically, the integrated porous electrode 11a and the current collector 11b may be integrated by, for example, ultrasonic welding or plasma welding, partially integrating the porous electrode 11a and the current collector 11b to ensure conductivity. The integrated porous electrode 11a and the current collector 11b may also be imparted with conductivity by interposing a conductive material, such as a conductive adhesive, between the porous electrode 11a and the current collector 11b. The conductive material is not particularly limited, and examples thereof include dispersed metal particles such as silver, gold, and nickel, carbon-based conductive materials, and conductive polymers.

[0042] (Negative Electrode) The negative electrode 12 is a gas-permeable electrode, and is not particularly limited as long as its specific surface area is smaller than that of the porous electrode 11a. Examples of the negative electrode 12 include a conductive material that is permeable to gases such as carbon dioxide and that can pass a current through the electrolyte layer 14 in contact with the negative electrode 12. The specific surface area of ​​the negative electrode 12 is smaller than that of the porous electrode 11a, and is 0.1 m2 in terms of BET specific surface area. ２ / g or more, and ２ / g or more, and ２ / g or more. In addition, the negative electrode 12 has a specific surface area of ​​200 m2 or more in terms of BET specific surface area. ２ / g or less, and ２ / g or less is more preferable, and 100m ２ Therefore, the BET specific surface area of ​​the negative electrode 12 is preferably 0.1 to 200 m / g. ２ / g, and 1 to 200m ２ / g, and more preferably 1 to 150m ２ / g, and more preferably 2 to 100m ２ / g is particularly preferable. Furthermore, the specific surface area of ​​the negative electrode 12 is preferably such that the ratio of the BET specific surface area of ​​the porous electrode 11a to the BET specific surface area of ​​the negative electrode 12 is within the above range. The BET specific surface area of ​​the negative electrode 12 is preferably high from the viewpoint of gas permeability (breathability). On the other hand, since it is preferable that carbon dioxide adsorption is prioritized over the adsorption of cations derived from the electrolyte solution, from this viewpoint, the BET specific surface area of ​​the negative electrode 12 is preferably low. When the BET specific surface area of ​​the negative electrode 12 is within the above range, charge / discharge and carbon dioxide adsorption / desorption can be performed favorably. For example, charge / discharge and carbon dioxide adsorption / desorption can be performed at a lower voltage or in a shorter time. This is thought to be due to the fact that carbon dioxide adsorption is more likely to occur preferentially in the negative electrode 12 than adsorption of cations derived from the electrolyte solution. The negative electrode 12 is an electrode that, when used together with the positive electrode 11, adsorbs carbon dioxide by electrolytic reduction and desorbs carbon dioxide by electrolytic oxidation. In the carbon dioxide adsorption battery 10, carbon dioxide is adsorbed to the negative electrode 12 during charging. Specifically, when the voltage is applied between the positive electrode and the negative electrode, the negative electrode 12 adsorbs carbon dioxide by electrolytic reduction. When the positive electrode and the negative electrode are subsequently discharged, for example, when the positive electrode 11 and the negative electrode 12 are electrically connected and discharged, the carbon dioxide adsorbed to the negative electrode is desorbed from the negative electrode. Specifically, the negative electrode 12 is electrolytically oxidized by the discharge, returning to its state before electrolytic reduction, so that the negative electrode 12 is no longer in a state in which carbon dioxide is adsorbed, and the carbon dioxide adsorbed to the negative electrode 12 is desorbed from the negative electrode 12. Therefore, when the above-described negative electrode is used as the negative electrode 12, it is possible to more reliably perform charging while adsorbing carbon dioxide from a gas containing carbon dioxide, and desorbing the carbon dioxide during discharge.

[0043] The negative electrode 12 is preferably a porous material that has conductivity sufficient to not inhibit electron transfer, is capable of storing charge, has excellent breathability, and has a large gas contact area. Specific examples of the negative electrode 12 include electrodes made of porous conductive materials and electrodes made of porous materials containing conductive materials. Examples of the porous conductive materials include porous metal layers, porous materials containing metal fibers, porous materials containing conductive fibers, porous materials containing carbon as a main component, and porous materials made of carbon. Examples of the carbon include conductive materials made of carbonaceous materials with a graphite structure, including at least one conductive material selected from the group consisting of graphite, carbon nanotubes, and carbon fibers. The carbon-containing porous material is preferably a carbonaceous material in the form of a cloth, felt, or porous sheet, such as a cloth or felt containing the carbonaceous material and a resin. Examples of the resin include PVDF, PTFE, styrene-butadiene rubber, and carboxymethyl cellulose. That is, the negative electrode 12 may be an electrode composed of a single conductive material among these porous conductive materials, or an electrode composed of a combination of two or more conductive materials. Furthermore, examples of conductive materials contained in the porous body include metal fibers, conductive fibers, metal particles, conductive ceramics, graphite, carbon nanotubes, activated carbon such as activated carbon fibers, and carbonaceous materials such as carbon fibers. Examples of the metal fibers and metal particles include those containing copper and silver. The porous body containing the metal fibers may be a porous conductive material. Furthermore, the conductive material is preferably graphite, carbon nanotubes, carbon black such as acetylene black, activated carbon, or carbon fiber. From the viewpoints of corrosion resistance and specific surface area, activated carbon such as activated carbon fibers is more preferable. The porous metal layer is a metal layer having a large number of pores formed therein. Furthermore, the pores of the porous metal layer are preferably formed throughout the entire metal layer due to their excellent breathability.The method for obtaining the porous metal layer is not particularly limited, as long as it involves subjecting a metal layer without pores (the metal layer before the pores are formed) to a treatment that forms a large number of pores (a method for making the metal layer porous). Examples of such methods include physical methods such as cutting, polishing, and sandblasting, and chemical methods such as electrolytic etching and electroless etching using an etching solution such as an acid or base. The above methods may be performed alone or in combination of two or more. From the viewpoint of increasing the surface area, chemical methods are preferred for making the pores (pores) more dense (forming denser pores). The material for the metal layer is not particularly limited, and examples include aluminum, copper, silver, gold, iron, titanium, molybdenum, tungsten, nickel, and alloys thereof. Among these, aluminum is preferred as the material for the metal layer from the viewpoints of price and processability. The metal layer before the pores are preferably aluminum foil. The conductive material may be used alone or in combination of two or more. The negative electrode 12 is preferably a carbon-based electrode using activated carbon or carbon fiber, or a highly porosity electrode using a needle-shaped conductive material. Specific examples of the negative electrode 12 include carbon sheets, carbon cloth, and carbon paper. Among the above-listed electrodes, the negative electrode 12 is preferably an electrode made of a conductive material containing at least one material selected from the group consisting of metal fibers, conductive fibers, metal particles, conductive ceramics, graphite, carbon nanotubes, activated carbon, and carbon fibers. Such an electrode is believed to not only allow the negative electrode 12 to more effectively apply a voltage between itself and the positive electrode 11, but also to more effectively transmit carbon dioxide. Therefore, using such an electrode as the negative electrode 12 results in a carbon dioxide adsorption battery that can more effectively adsorb carbon dioxide from a carbon dioxide-containing gas during charging and more effectively release carbon dioxide during discharging.

[0044] The negative electrode 12 may further include a current collector. That is, the negative electrode 12 may be made of the porous body, or may include the porous body and the current collector. The current collector is not particularly limited as long as it does not hinder the gas permeation. For example, the current collector may be made of a conductive material and have openings to the extent that the gas permeation is not hindered. More specifically, the current collector may be made of a metal such as mesh metal, punched metal, or expanded metal, or may be a woven or nonwoven fabric made of natural or synthetic fibers plated to provide conductivity. Examples of metals that can be used as the current collector include stainless steel, iron, nickel, titanium, and copper.

[0045] In an electrode including the porous body and the current collector, the porous body and the current collector are preferably integrated, and the method for integration is not particularly limited. The integrated porous body and the current collector may be partially integrated using, for example, ultrasonic welding or plasma welding to ensure electrical conductivity. The integrated porous body and the current collector may also be electrically conductive by interposing a conductive material, such as a conductive adhesive, between the porous body and the current collector. The conductive material is not particularly limited, and examples of the conductive material include dispersed metal particles such as silver, gold, and nickel, carbon-based conductive materials, and conductive polymers.

[0046] As described above, the negative electrode 12 is a conductive member that can pass current to the electrolyte layer 14 in contact with the negative electrode 12, and the smaller its surface resistance is, the more preferable it is, for example, preferably 1 kΩ / sq or less, and more preferably 200 Ω / sq or less. Furthermore, the smaller the surface resistance of the negative electrode 12 is, the more preferable it is. In practice, the surface resistance is limited to 1 Ω / sq, and is often approximately 10 Ω / sq or more. Therefore, the surface resistance of the negative electrode 12 is preferably 1 Ω / sq to 1 kΩ / sq, and more preferably 10 to 200 Ω / sq. An electrode with such a surface resistance value can favorably pass current to the electrolyte layer 14, and can favorably separate carbon dioxide.

[0047] The thickness of the negative electrode 12 is not particularly limited, but is preferably a thickness that can adsorb carbon dioxide and suitably prevent leakage of the electrolyte. The thickness of the negative electrode 12 is preferably, for example, 20 μm to 10 mm, and more preferably 50 μm to 5 mm. If the negative electrode 12 is too thin, the strength of the electrode tends to be insufficient. Furthermore, if the negative electrode 12 is too thick, the gas permeability (breathability) tends to decrease, and the permeation of carbon dioxide tends to be inhibited. For these reasons, if the thickness of the negative electrode 12 is within the above range, carbon dioxide separation can be achieved for a long period of time.

[0048] (Electrolyte Layer) The electrolyte layer 14 is not particularly limited as long as it contains an electrolyte solution capable of dissolving carbon dioxide. The electrolyte solution is not particularly limited as long as it is capable of dissolving carbon dioxide, and may be an electrolyte solution containing an electrolyte and a solvent, an electrolyte solution containing an ionic liquid, or an electrolyte solution made of an ionic liquid. Note that an electrolyte solution capable of dissolving carbon dioxide may be any electrolyte solution other than one in which carbon dioxide is not dissolved. In other words, it may be an electrolyte solution in which even a small amount of carbon dioxide dissolves, and high solubility is not required. This is thought to be due to the following. As described above, in the carbon dioxide adsorption battery 10 according to this embodiment, due to the binding and desorption of carbon dioxide to the negative electrode 12, carbon dioxide in contact with the negative electrode 12 or carbon dioxide dissolved in the electrolyte solution is adsorbed to the negative electrode 12 during charging, thereby promoting the dissolution of carbon dioxide into the electrolyte solution. Therefore, it is thought that even a small amount of carbon dioxide dissolving in the electrolyte solution contained in the electrolyte layer 14 will promote the adsorption and release of carbon dioxide. As described above, the electrolyte layer 14 is only required to contain an electrolyte solution capable of dissolving carbon dioxide, and may further contain a redox compound such as a compound capable of absorbing and desorbing carbon dioxide through an electrochemical reaction, but it is preferable that the electrolyte layer 14 does not contain the redox compound.

[0049] As described above, the electrolyte solution is not particularly limited as long as it is capable of dissolving carbon dioxide, but is preferably nonvolatile. As described above, the electrolyte solution may be an electrolyte solution containing an electrolyte and a solvent, an electrolyte solution containing an ionic liquid, or an electrolyte solution consisting of an ionic liquid. However, a nonvolatile solution that can be used as an electrolyte is preferred. Specifically, the electrolyte solution is preferably an ionic liquid. By using an ionic liquid as the electrolyte solution contained in the electrolyte layer 14, the carbon dioxide adsorption battery 10 can more efficiently perform charge / discharge and adsorption / desorption of carbon dioxide. For example, charge / discharge and adsorption / desorption of carbon dioxide can be performed at a lower voltage or in a shorter time. This is thought to be due to the fact that carbon dioxide adsorption is more easily performed at the negative electrode 12 and the anion adsorption is more easily performed at the positive electrode 11.

[0050] The solvent is preferably an electrochemically stable compound with a wide potential window, and may be either an aqueous solvent or an organic solvent. Examples of the solvent include water, carbonate compounds, ester compounds, ether compounds, heterocyclic compounds, nitrile compounds, and aprotic polar compounds. Examples of the carbonate compounds include dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, and propylene carbonate. Examples of the ester compounds include methyl acetate, methyl propionate, and γ-butyrolactone. Examples of the ether compounds include diethyl ether, 1,2-dimethoxyethane, 1,3-dioxosilane, tetrahydrofuran, and 2-methyl-tetrahydrofuran. Examples of the heterocyclic compounds include 3-methyl-2-oxazolidinone and 2-methylpyrrolidone. Examples of the nitrile compounds include acetonitrile, methoxyacetonitrile, propionitrile, 3-methoxypropionitrile, and valeric acid nitrile. Examples of the aprotic polar compound include sulfolane, dimethyl sulfoxide, and dimethylformamide. As the solvent, the exemplified solvents may be used alone or in combination of two or more. Among the exemplified solvents, preferred solvents include carbonate compounds such as ethylene carbonate and propylene carbonate, ester compounds such as γ-butyrolactone, heterocyclic compounds such as 3-methyl-2-oxazolidinone and 2-methylpyrrolidone, and nitrile compounds such as acetonitrile, methoxyacetonitrile, propionitrile, 3-methoxypropionitrile, and valeric acid nitrile. When two or more solvents are used in combination, water is preferred from the viewpoint of dissolving carbon dioxide.

[0051] The electrolyte is not particularly limited, and examples thereof include quaternary ammonium salts, inorganic salts, and hydroxides. Examples of the quaternary ammonium salts include tetramethylammonium tetrafluoroborate, tetra-n-ethylammonium tetrafluoroborate, tetra-n-propylammonium tetrafluoroborate, tetra-n-butylammonium tetrafluoroborate, n-hexadecyltrimethylammonium tetrafluoroborate, tetra-n-hexadecylammonium tetrafluoroborate, tetra-n-octylammonium tetrafluoroborate, tetra-n-ethylammonium perchlorate, tetra-n-butylammonium perchlorate, and tetraoctadecylammonium perchlorate. Examples of the inorganic salts include lithium perchlorate, sodium perchlorate, potassium perchlorate, sodium acetate, potassium acetate, sodium nitrate, and potassium nitrate. Examples of the hydroxides include sodium hydroxide and potassium hydroxide. Among the electrolytes exemplified above, the electrolyte is preferably tetramethylammonium tetrafluoroborate, tetra-n-ethylammonium tetrafluoroborate, tetra-n-propylammonium tetrafluoroborate, tetra-n-butylammonium tetrafluoroborate, n-hexadecyltrimethylammonium tetrafluoroborate, tetra-n-hexadecylammonium tetrafluoroborate, tetra-n-octylammonium tetrafluoroborate, tetra-n-ethylammonium perchlorate, tetra-n-butylammonium perchlorate, tetraoctadecylammonium perchlorate, lithium perchlorate, sodium perchlorate, sodium acetate, or potassium acetate. Furthermore, among these, the electrolyte is more preferably tetra-n-ethylammonium tetrafluoroborate, tetra-n-propylammonium tetrafluoroborate, tetra-n-butylammonium tetrafluoroborate, lithium perchlorate, or sodium perchlorate, and further preferably tetra-n-butylammonium tetrafluoroborate or lithium perchlorate.The electrolyte may also have a pH buffering ability by stabilizing carbonate ions or bicarbonate ions as a supporting salt. Specific examples of the electrolyte include sodium bicarbonate, sodium carbonate, acetic acid, and sodium acetate. The above-listed electrolytes may be used alone or in combination of two or more.

[0052] As described above, the electrolyte solution may be an electrolyte solution containing an ionic liquid (ionic liquid), or may be an electrolyte solution consisting of an ionic liquid. When an ionic liquid is used as the electrolyte solution, the ionic liquid can have the functions of both an electrolyte and a solvent, as described above, without the need to contain both. Furthermore, the electrolyte solution may contain an ionic liquid, and may be a liquid containing an electrolyte in an ionic liquid, a liquid containing a solvent in an ionic liquid, a liquid containing an electrolyte and a solvent in an ionic liquid, or a liquid consisting of an ionic liquid. Furthermore, using an ionic liquid as the electrolyte solution is preferable because the ionic liquid is less likely to volatilize and has high flame retardancy.

[0053] The ionic liquid is not particularly limited as long as it is a known ionic liquid, and examples thereof include imidazolium-based ionic liquids, pyridine-based ionic liquids, alicyclic amine-based ionic liquids, and azonium amine-based ionic liquids. Examples of the ionic liquid include 1-methyl-3-octylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-decyl-3-methylimidazolium tetrafluoroborate, 1,3-dimethoxyimidazolium tetrafluoroborate, 1,3-diethoxyimidazolium tetrafluoroborate, 1-methyl-3- Examples of the fluoroimidazolium hexafluorophosphate include octylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-decyl-3-methylimidazolium hexafluorophosphate, 1,3-dimethoxyimidazolium hexafluorophosphate, 1,3-diethoxyimidazolium hexafluorophosphate, and 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide. Furthermore, among the ionic liquids exemplified above, 1-methyl-3-octylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonylimide), 1,3-dimethoxyimidazolium tetrafluoroborate, 1-methyl-3-octylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium hexafluorophosphate, and 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide are preferred as the ionic liquid.Moreover, as the ionic liquid, 1-methyl-3-octylimidazolium tetrafluoroborate, 1,3-dimethoxyimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonylimide), 1-butyl-3-methylimidazolium chloride, 1-methyl-3-octylimidazolium hexafluorophosphate, and 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide are more preferable, and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonylimide), 1-butyl-3-methylimidazolium chloride, 1-methyl-3-octylimidazolium tetrafluoroborate, and 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide are even more preferable.

[0054] The electrolyte layer 14 may include a substrate. Examples of the electrolyte layer 14 include a substrate impregnated with the electrolytic solution. Examples of the substrate include glass fiber filter paper.

[0055] The method for manufacturing the electrolyte layer 14 is not particularly limited as long as the electrolyte layer 14 can be manufactured. When the electrolyte layer 14 includes the base material, for example, a method of impregnating the base material with the electrolyte solution can be used. The impregnation is preferably performed while applying ultrasonic vibrations to the electrolyte solution and the base material. This can prevent minute holes, i.e., pinholes, from being formed in the electrolyte layer 14.

[0056] The electrolyte layer 14 may be formed by gelling the electrolyte solution. Specifically, a gelling agent for gelling the electrolyte solution may be added, or a gelled electrolyte or polymer electrolyte may be used. Examples of the gelling agent include polymers, gelling agents using techniques such as polymer crosslinking reactions, polymerizable polyfunctional monomers, and oil gelling agents. The gelled electrolyte and polymer electrolyte are not particularly limited as long as they can be used as a gelled electrolyte or polymer electrolyte. Examples include vinylidene fluoride polymers such as polyvinylidene fluoride, acrylic acid polymers such as polyacrylic acid, acrylonitrile polymers such as polyacrylonitrile, polyether polymers such as polyethylene oxide, and compounds having an amide structure in their structure.

[0057] As described above, it is preferable that the electrolyte layer 14 does not contain the redox compound. However, if the electrolyte layer 14 contains the redox compound, examples of the redox compound include the following compounds. Examples of the redox compound include compounds that adsorb carbon dioxide through electrolytic reduction and desorb carbon dioxide through electrolytic oxidation. Examples of the redox compound include compounds having at least one of a quinone group and an N-oxy radical group in the molecule. That is, specific examples of the redox compound include compounds having a quinone group in the molecule, compounds having an N-oxy radical group in the molecule, and compounds having a quinone group and an N-oxy radical group in the molecule. Examples of the compound having a quinone group in the molecule include benzoquinone, naphthoquinone, and anthraquinone. Examples of the compound having an N-oxy radical group in the molecule include compounds in which two quaternary carbons are bonded to the N-oxy radical group.

[0058] Examples of the redox compound include 1,4-di(1-oxy-2,2,6,6-tetramethyl-1-piperidin-4-yloxy)xylene, 4-acetamido-2,2,6,6-tetramethylpiperidine 1-oxyl, N,N-di-tert-butyl nitroxide radical, N,N-diphenyl nitroxide radical, N,N-dinaphthyl nitroxide radical, N,N-di-2-methylphenyl nitroxide radical, N,N-di-3-methylphenyl nitroxide radical, N,N-di-4-methylphenyl nitroxide radical, N,N- Di-2-ethylphenyl nitroxide radical, N,N-di-2-propylphenyl nitroxide radical, N,N-di-2-butylphenyl nitroxide radical, N,N-di-2-pentylphenyl nitroxide radical, N,N-di-2-hexylphenyl nitroxide radical, N,N-di-2-isopropylphenyl nitroxide radical, N,N-di-2-isobutylphenyl nitroxide radical, N,N-di-2-sec-butylphenyl nitroxide radical, N,N-di-2-tert-butylphenyl nitroxide radical, N , N-di-4-tert-butylphenyl nitroxide radical, N,N-di-(3,5-di-tert-butyl)phenyl nitroxide radical, N,N-di-4-pyridyl nitroxide radical, N,N-di-4-pyridazyl nitroxide radical, poly(ethylene glycol)-bis-2,2,6,6-tetramethylpiperidinyloxy radical, N-phenyl-N-oxy-tert-butylamine, N-naphthyl-N-oxy-tert-butylamine, N-tert-butyl-N-oxy-2-quinoline, 2,2,6,6-tetramethylpiperidinyloxy radical tetramethylpiperidinyloxy radical (TEMPO), 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy radical, 4-amino-2,2,6,6-tetramethylpiperidinyloxy radical, 4-carboxy-2,2,6,6-tetramethylpiperidinyloxy radical, 4-methoxy-2,2,6,6-tetramethylpiperidinyloxy radical, 4-oxo-2,2,6,6-tetramethylpiperidinyloxy radical, 4-acetamido-2,2,6,6-tetramethylpiperidinyloxy radical, 4-octyloxy-2,2,6,6-tetramethylpiperidinyloxy radical, 2,2,5,5-tetramethylpyrrolidineoxy radical, 3-carbamoyl-2,2,5,5-tetramethylpyrrolidineoxy radical, 3-carboxy-2,2,5,5-tetramethylpyrrolidineoxy radical, 2,2,6,6-tetramethylmorpholine-N-oxy radical, 2,2,6,6-tetramethylmorpholinepiperazine-N-oxy radical, γ-dimethyl-butyrolactam-N-oxide, ε-dimethyl-valerolactam-N-oxide, 3,4-dihydroquinolin-2-one-N-oxide, 3,3-dimethylisoquinolin-1-one-N-oxide, 3,3-dimethyl-1H-indo Examples of the redox compound include benzoyl-2(3H)-one-N-oxide, 3,3-dimethyl-isoindolin-1-one-N-oxide, N-t-butylbenzoic acid-N-oxide, 1α,2α-cyclohexanedicarboximide-N-oxyl, phthalimide-N-oxyl, 3-methyl-phthalimide-N-oxyl, 4-methyl-phthalimide-N-oxyl, 4-carboxy-phthalimide-N-oxyl, naphthalene-2,3-dicarboximide-N-oxyl, pyromellitimide-di-N-oxyl, trihydroxyiminocyanuric acid-N-oxyl, trihydroxyiminocyanuric acid-di-N-oxyl, and trihydroxyiminocyanuric acid-tri-N-oxyl. As described above, the redox compound may be a polymer compound. Examples of the polymer compound include a 4-acryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical, a 4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical, a 3-acryloyloxy-2,2,6,6-tetramethylpyrrolidinyloxy radical, a 3-methacryloyloxy-2,2,6,6-tetramethylpyrrolidinyloxy radical, a 4-vinyloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical, and a 4-vinyloyloxy-2,2,5,Examples include compounds obtained by polymerizing a monomer such as 5-tetramethylpyrrolidinyloxy radical. The polymeric compound may be a compound obtained by polymerizing the monomer alone, or may be a compound obtained by polymerizing two or more of the monomers in combination. Among the redox compounds exemplified above, 1,4-di(1-oxy-2,2,6,6-tetramethyl-1-piperidin-4-yloxy)xylene, 4-acetamido-2,2,6,6-tetramethylpiperidine 1-oxyl, and poly(4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical) are preferred. As mentioned above, it is preferable not to include the redox compound. However, if the redox compound is included, it may be used alone or in combination of two or more.

[0059] (Separator) The separator 13 is not particularly limited as long as it prevents direct contact between the positive electrode 11 and the negative electrode 12 and is permeable to the electrolyte. That is, the separator 13 is permeable to the electrolyte but prevents direct contact between the positive electrode and the negative electrode. Furthermore, when an electrolyte containing a redox compound is used, the separator 13 is less permeable to the redox compound than to the electrolyte. For example, the separator 13 is preferably permeable to the electrolyte but not to the redox compound. The separator 13 is permeable to the electrolyte and is provided to separate the electrolyte layer 14 from the porous electrode 11a. Thus, the positive electrode 11 and the negative electrode 12 are separated by the separator 13. Examples of the separator 13 include separators commonly used in lithium secondary batteries. In particular, separators that have low resistance to ion migration of the electrolyte and excellent electrolyte humidification ability are preferred. Examples of the separator material include glass fiber, polyester, polyethylene, polypropylene, and polytetrafluoroethylene (PTFE). The separator material may be used alone or in combination of two or more. The separator 13 is made of the separator material and may be in the form of a nonwoven fabric or a woven fabric. The pore size of the separator 13 is not particularly limited and is preferably, for example, 0.01 to 10 μm. The thickness of the separator 13 is not particularly limited and is preferably, for example, 5 to 300 μm.

[0060] (Flow Channel) The flow channel 15 is not particularly limited as long as it is a flow channel through which gas can flow. The flow channel 15 is connected to the negative electrode 12 and can flow gas permeating the negative electrode 12 and gas released from the negative electrode 12. The gas is not particularly limited as long as it contains carbon dioxide and oxygen, and examples thereof include gases containing carbon dioxide, oxygen, and nitrogen, and more specifically, air. Thus, when the gas present around the negative electrode contains oxygen, the oxygen contained in the gas present around the negative electrode will come into contact with the negative electrode 12. When the gas present around the negative electrode contains carbon dioxide, the carbon dioxide contained in the gas present around the negative electrode will come into contact with the negative electrode 12. The flow channel 15 is preferably, for example, a flow channel through which at least one of carbon dioxide adsorbed to the negative electrode 12 and carbon dioxide desorbed from the negative electrode 12 can flow. If the flow path 15 is of this type, in the carbon dioxide adsorption battery 10, carbon dioxide adsorbed to the negative electrode 12 can be made to flow through the flow path during charging, and carbon dioxide desorbed from the negative electrode 12 can be made to flow through the flow path during discharging. Thus, in the carbon dioxide adsorption battery 10, it is possible to more reliably charge the battery while adsorbing carbon dioxide from a gas containing carbon dioxide, and desorb the carbon dioxide during discharging. Furthermore, the flow path 15 may be provided with a valve 18, as necessary.

[0061] (Voltage Application Unit) As described above, the carbon dioxide adsorption battery 10 may be provided with the voltage application unit 16. By providing the carbon dioxide adsorption battery 10 with the voltage application unit 16, it is possible to make the carbon dioxide adsorption battery 10 into a carbon dioxide concentrator capable of concentrating carbon dioxide. That is, a carbon dioxide concentrator is obtained that includes the carbon dioxide adsorption battery 10 and the voltage application unit 16 that applies a voltage between the positive electrode 11 and the negative electrode 12.

[0062] The voltage application unit 16 is not particularly limited as long as it can apply the voltage between the positive electrode 11 and the negative electrode 12. Examples of the voltage application unit 16 include a secondary battery, an external power source, and a capacitor.

[0063] (Resistor) After charging, the carbon dioxide adsorption battery 10 is discharged by providing the resistor 17 between the positive electrode 11 and the negative electrode 12, as shown in Fig. 2. The resistor 17 is not particularly limited as long as it can discharge the carbon dioxide adsorption battery 10.

[0064] (Manufacturing Method) There is no particular limitation on the manufacturing method of the carbon dioxide adsorption battery 10 as long as it can be manufactured to have the above structure. Specific examples of the manufacturing method of the carbon dioxide adsorption battery 10 include a method of assembling the positive electrode 11, the negative electrode 12, the separator 13, the electrolyte layer 14, and the flow path 15, and further using the voltage application unit 16, the resistor 17, and the like, as necessary, by a general assembly method to form a structure such as that shown in FIGS. 1 and 2 .

[0065] [Other Carbon Dioxide Adsorption Batteries] The carbon dioxide adsorption battery according to the present embodiment is not limited to the carbon dioxide adsorption battery having the above-described configuration, as long as it includes the positive electrode, the negative electrode, and the electrolyte layer. For example, a carbon dioxide adsorption battery 20 not including a separator, as shown in FIGS. 3 and 4 , may be used. The carbon dioxide adsorption battery 10 does not need to include a separator because the electrolyte layer 14 is disposed between the positive electrode 11 and the negative electrode 12. However, the carbon dioxide adsorption battery 10 includes the separator 13. Another carbon dioxide adsorption battery according to the present embodiment may be a carbon dioxide adsorption battery 20 having a configuration similar to that of the carbon dioxide adsorption battery 10 shown in FIGS. 1 and 2 except that it does not include a separator. FIGS. 3 and 4 are schematic cross-sectional views showing another example of the configuration of a carbon dioxide adsorption battery according to an embodiment of the present invention (the carbon dioxide adsorption battery 20). FIG. 3 shows the carbon dioxide adsorption battery 20 during charging, and FIG. 4 shows the carbon dioxide adsorption battery 20 during discharging. When a separator is not provided, for example, in the case of a carbon dioxide adsorption battery 20 as shown in FIGS. 3 and 4 , it is preferable that the positive electrode 11 and the negative electrode 12 are not in direct contact with each other. For example, it is preferable that the electrolyte layer 14 disposed between the positive electrode 11 and the negative electrode 12 is formed by gelling the electrolytic solution.

[0066] Another carbon dioxide adsorption battery according to this embodiment may include, for example, one positive electrode and two negative electrodes disposed on both sides of the positive electrode. Specifically, as shown in FIGS. 5 and 6 , a carbon dioxide adsorption battery 30 includes the positive electrode 11, two negative electrodes 12 disposed on both sides of the positive electrode 11, two separators 13 disposed between the positive electrode 11 and each negative electrode 12, two electrolyte layers 14 disposed between each negative electrode 12 and each separator 13, and two flow paths 15 connected to each negative electrode 12. Note that although the carbon dioxide adsorption battery 30 includes the separator 13, a separator is not required. The positive electrode 11 may include the porous electrode 11a and be composed of the porous electrode 11a. However, when the porous electrode 11a and the current collector 11b are included as shown in FIG. 5 , the porous electrode 11a is provided on both sides of the current collector 11b. In such a carbon dioxide adsorption battery 30, carbon dioxide is adsorbed to each of the negative electrodes 12 during charging. That is, during charging, a gas containing carbon dioxide and oxygen is circulated through the two flow paths 15, causing carbon dioxide to be adsorbed to each of the negative electrodes 12, and charging is performed. Then, as shown in FIG. 6 , carbon dioxide can be released from each of the negative electrodes 12 by discharging. As a result, the carbon dioxide adsorption battery 30 can adsorb and desorb carbon dioxide from either of the negative electrodes 12. As a result, the carbon dioxide adsorption battery can be charged while adsorbing carbon dioxide from a gas containing carbon dioxide, and can desorb the carbon dioxide during discharge more efficiently, even at a low voltage. FIGS. 5 and 6 are schematic cross-sectional views showing another example of the configuration of a carbon dioxide adsorption battery (the carbon dioxide adsorption battery 30) according to an embodiment of the present invention. FIG. 5 shows the carbon dioxide adsorption battery 30 during charging, and FIG. 6 shows the carbon dioxide adsorption battery 30 during discharging.

[0067] [Charging / Discharging Device] The charging / discharging device according to the embodiment of the present invention is a charging / discharging device including two or more of the carbon dioxide adsorption batteries. The charging / discharging device is not particularly limited as long as it includes two or more of the carbon dioxide adsorption batteries, and examples thereof include a charging / discharging device 40 as shown in FIG.

[0068] 7 , the charging / discharging device 40 includes a first carbon dioxide adsorption battery 10a and a second carbon dioxide adsorption battery 10b. The first carbon dioxide adsorption battery 10a can be charged by connecting its negative electrode side 10a1 and positive electrode side 10a2 via the voltage application unit 16. That is, the charging / discharging device 40 can charge the first carbon dioxide adsorption battery 10a by connecting the positive electrode side 10a2 of the first carbon dioxide adsorption battery 10a and the voltage application unit 16 with a wiring 31, and connecting the voltage application unit 16 and the negative electrode side 10a1 of the first carbon dioxide adsorption battery 10a with a wiring 32. After charging the first carbon dioxide adsorption battery 10a, the negative electrode side 10a1 of the first carbon dioxide adsorption battery 10a and the negative electrode side 10b1 of the second carbon dioxide adsorption battery 10b are connected by a wiring 36, and the positive electrode side 10b2 of the second carbon dioxide adsorption battery 10b and the positive electrode side 10a2 of the first carbon dioxide adsorption battery 10a are connected by a wiring 35, thereby discharging the first carbon dioxide adsorption battery 10a and charging the second carbon dioxide adsorption battery 10b. After charging the second carbon dioxide adsorption battery 10b (after discharging the first carbon dioxide adsorption battery 10a), the negative electrode 10b1 of the second carbon dioxide adsorption battery 10b is connected to the negative electrode 10a1 of the first carbon dioxide adsorption battery 10a via a wiring 34, and the positive electrode 10a2 of the first carbon dioxide adsorption battery 10a is connected to the positive electrode 10b2 of the second carbon dioxide adsorption battery 10b via a wiring 33. This allows the second carbon dioxide adsorption battery 10b to be discharged while the first carbon dioxide adsorption battery 10a is charged. In this way, by once charging the first carbon dioxide adsorption battery 10a, the device can function as a charge / discharge device that can alternately charge and discharge the second carbon dioxide adsorption battery 10b and the first carbon dioxide adsorption battery 10a. Therefore, by including two or more carbon dioxide adsorption batteries, the charge / discharge device can alternately charge and discharge each of the carbon dioxide adsorption batteries. This makes the charge / discharge device highly energy efficient. The charging / discharging device can also separate carbon dioxide.In the first carbon dioxide adsorption battery 10a and the second carbon dioxide adsorption battery 10b, carbon dioxide is adsorbed from a gas containing carbon dioxide (such as air containing nitrogen and carbon dioxide) during charging, and the adsorbed carbon dioxide is released during discharging. Fig. 7 is a schematic diagram showing an example of the configuration of a charge / discharge device according to an embodiment of the present invention.

[0069] As described above, this specification discloses various aspects of the technology, the main technologies of which are summarized below.

[0070] A carbon dioxide adsorption battery according to a first aspect of the present invention includes a positive electrode, a negative electrode, an electrolyte layer disposed between the positive electrode and the negative electrode, and a flow path connected to the negative electrode, wherein the electrolyte layer contains an electrolyte solution capable of dissolving carbon dioxide, the negative electrode is a gas-permeable electrode, and the positive electrode includes a porous electrode, and the porous electrode has a specific surface area of ​​100 to 3000 m in terms of BET specific surface area. ２ / g and is larger than the specific surface area of ​​the negative electrode.

[0071] With this configuration, it is possible to provide a carbon dioxide adsorption battery that can adsorb carbon dioxide from a gas containing carbon dioxide while charging and desorb the carbon dioxide during discharge in a short time even at a low voltage. This is believed to be due to the following reasons.

[0072] The negative electrode allows gas present around the negative electrode to pass through. When gas passes through the negative electrode, the gas that has passed through the negative electrode comes into contact with the negative electrode side of the electrolyte layer and the electrolyte solution contained in the electrolyte layer. Furthermore, if the electrolyte solution contained in the electrolyte layer has migrated to the negative electrode, the gas will also come into contact with the electrolyte solution that has migrated to the negative electrode when passing through the negative electrode. Therefore, if the gas present around the negative electrode contains carbon dioxide, the carbon dioxide contained in the gas present around the negative electrode will be dissolved in the electrolyte solution. Furthermore, if the gas present around the negative electrode contains oxygen, the oxygen contained in the gas present around the negative electrode will come into contact not only with the negative electrode but also with the negative electrode side of the electrolyte layer.

[0073] When a gas containing carbon dioxide and oxygen is circulated through a flow path connected to the negative electrode and a voltage is applied between the positive electrode and the negative electrode, the carbon dioxide is adsorbed to the negative electrode. The mechanism by which carbon dioxide is adsorbed is unclear, but is thought to be the following mechanism. When a voltage is applied between the positive electrode and the negative electrode and electrons flow into the negative electrode, oxygen in contact with the negative electrode and the negative electrode side of the electrolyte layer is reduced to a reduced form such as a superoxide radical, which is then bound to the negative electrode. It is thought that carbon dioxide is adsorbed to the negative electrode by the reduced form such as a superoxide radical binding to the negative electrode, which in turn binds to carbon dioxide present around the negative electrode or carbon dioxide dissolved in the electrolyte. Furthermore, when a voltage is applied between the positive electrode and the negative electrode and electrons flow into the negative electrode, carbon dioxide is adsorbed to the negative electrode, and cations derived from the electrolyte are also adsorbed to the negative electrode. Such cation adsorption tends to occur more easily when the specific surface area of ​​the negative electrode is high, and tends to occur less easily when the specific surface area of ​​the negative electrode is low. Therefore, when the specific surface area of ​​the negative electrode is low, adsorption of carbon dioxide onto the negative electrode tends to occur more easily than adsorption of the cations. For this reason, when the BET specific surface area is 100 to 3000 m, ２ When a negative electrode having a specific surface area smaller than that of the porous electrode having a specific surface area of ​​0.1 / g is used, carbon dioxide tends to be preferentially adsorbed onto the negative electrode.

[0074] Therefore, when a voltage that reduces oxygen in contact with the negative electrode is applied between the positive electrode and the negative electrode, the carbon dioxide adsorption battery enters a state in which carbon dioxide is adsorbed to the negative electrode through an electrochemical reaction, and carbon dioxide in contact with the negative electrode and carbon dioxide dissolved in the electrolyte are adsorbed to the negative electrode. When carbon dioxide is adsorbed to the negative electrode in this manner, the carbon dioxide adsorption battery enters a charged state. Furthermore, since carbon dioxide in contact with the negative electrode and carbon dioxide dissolved in the electrolyte are adsorbed to the negative electrode, the dissolution of carbon dioxide into the electrolyte is promoted, which promotes the permeation of carbon dioxide from the negative electrode, and the carbon dioxide adsorption battery preferably proceeds to a charged state. For these reasons, as shown in FIG. 1 , in the carbon dioxide adsorption battery, when a gas containing carbon dioxide and oxygen is circulated through a flow path connected to the negative electrode and a voltage that reduces oxygen in contact with the negative electrode is applied between the positive electrode and the negative electrode, carbon dioxide is adsorbed and the battery can be charged. Furthermore, in the carbon dioxide adsorption battery, as described above, at least the electrolyte layer is present between the positive electrode and the negative electrode. Therefore, even if the application of voltage between the positive electrode and the negative electrode is stopped, the state in which carbon dioxide is adsorbed, i.e., the charged state, is suitably maintained unless the battery is discharged.

[0075] Thereafter, when the battery is discharged, for example, when the positive electrode and the negative electrode are electrically connected and the battery is discharged, the state in which carbon dioxide is adsorbed to the negative electrode by an electrochemical reaction is eliminated, and the carbon dioxide adsorbed to the negative electrode is desorbed from the negative electrode. Thus, in the carbon dioxide adsorption battery, when the battery is discharged, carbon dioxide is released from the negative electrode into the flow path connected to the negative electrode. The gas released from the carbon dioxide adsorption battery when the battery is discharged is supplemented with the carbon dioxide adsorbed to the negative electrode in the carbon dioxide adsorption battery when the battery is charged, thereby increasing the carbon dioxide concentration and enabling the carbon dioxide to be concentrated.

[0076] In the carbon dioxide adsorption battery, when the voltage is applied between the positive electrode and the negative electrode and electrons are extracted from the positive electrode, anions derived from the electrolyte are adsorbed to the positive electrode. The carbon dioxide adsorption battery operates also due to the adsorption of anions to the positive electrode. That is, the carbon dioxide adsorption battery also performs charge compensation (specifically, charge compensation like a capacitor) at the positive electrode without the electrochemical reaction. In this case, the carbon dioxide adsorption battery has a BET specific surface area of ​​100 to 3000 m. ２ This charge compensation can be suitably performed by using a positive electrode having a porous electrode with a specific surface area greater than that of the negative electrode, where the specific surface area is 0.1 / g. This charge compensation has lower resistance than the case involving the electrochemical reaction, and therefore can contribute to driving at a lower voltage (i.e., lower power consumption) than conventional techniques. As described above, the negative electrode also adsorbs cations derived from the electrolyte, but adsorption of carbon dioxide occurs preferentially, so that charging is performed while adsorbing carbon dioxide along with this charge compensation.

[0077] As described above, the carbon dioxide adsorption battery can be charged while adsorbing carbon dioxide from a gas containing carbon dioxide, and can desorb the carbon dioxide during discharge in a short time even at a low voltage.

[0078] A carbon dioxide adsorption battery according to a second aspect of the present invention is the carbon dioxide adsorption battery according to the first aspect of the present invention, wherein the ratio of the BET specific surface area of ​​the porous electrode to the BET specific surface area of ​​the negative electrode is 10 to 3000 times.

[0079] This configuration allows for more efficient charge / discharge and carbon dioxide adsorption / desorption. For example, charge / discharge and carbon dioxide adsorption / desorption can be performed at lower voltages or in a shorter time. This is thought to be because carbon dioxide adsorption occurs more preferentially than cation adsorption at the negative electrode, and anion adsorption occurs more efficiently at the positive electrode.

[0080] A carbon dioxide adsorption battery according to a third aspect of the present invention is the carbon dioxide adsorption battery according to the first or second aspect of the present invention, further comprising a separator disposed between the positive electrode and the electrolyte layer.

[0081] With this configuration, charging / discharging and adsorption / desorption of carbon dioxide can be performed more efficiently. This is believed to be due to the following: The separator disposed between the positive electrode and the electrolyte layer can further suppress electrical contact between the positive electrode and the negative electrode. This is believed to be because, when a voltage is applied between the positive electrode and the negative electrode and the voltage application is stopped, the state in which carbon dioxide is adsorbed, i.e., the charged state, is more efficiently maintained as long as no discharge occurs.

[0082] A carbon dioxide adsorption battery according to a fourth aspect of the present invention is the carbon dioxide adsorption battery according to any one of the first to third aspects of the present invention, wherein the specific surface area of ​​the negative electrode is 0.1 to 200 m in terms of BET specific surface area. ２ / g of carbon dioxide adsorption battery.

[0083] This configuration allows for more efficient charge / discharge and carbon dioxide adsorption / desorption. For example, charge / discharge and carbon dioxide adsorption / desorption can be performed at a lower voltage or in a shorter time. This is believed to be due to the fact that carbon dioxide adsorption occurs more preferentially than cation adsorption at the negative electrode.

[0084] A carbon dioxide adsorption battery according to a fifth aspect of the present invention is the carbon dioxide adsorption battery according to any one of the first to fourth aspects of the present invention, wherein the porous electrode contains the electrolyte solution.

[0085] This configuration allows charge / discharge and carbon dioxide adsorption / desorption to be performed more efficiently. For example, charge / discharge and carbon dioxide adsorption / desorption can be performed at a lower voltage or in a shorter time. This is believed to be due to the following reasons.

[0086] In the carbon dioxide adsorption battery, even if the above-described adsorption and desorption of carbon dioxide does not occur, charge compensation without the electrochemical reaction is performed by the anion adsorption in the positive electrode, and this charge compensation enables charging and discharging. It is believed that the anion adsorption can be performed more effectively when the porous electrode contains the electrolyte.

[0087] A carbon dioxide adsorption battery according to a sixth aspect of the present invention is the carbon dioxide adsorption battery according to any one of the first to fifth aspects of the present invention, wherein the flow path is a flow path through which at least one of carbon dioxide adsorbed by the negative electrode and carbon dioxide desorbed from the negative electrode can flow.

[0088] According to this configuration, in the carbon dioxide adsorption battery, carbon dioxide adsorbed to the negative electrode can be caused to flow through the flow path during charging, and carbon dioxide desorbed from the negative electrode can be caused to flow through the flow path during discharging. Therefore, the carbon dioxide adsorption battery can more reliably be charged while adsorbing carbon dioxide from a gas containing carbon dioxide, as described above, and desorb the carbon dioxide during discharging.

[0089] A carbon dioxide adsorption battery according to a seventh aspect of the present invention is the carbon dioxide adsorption battery according to any one of the first to sixth aspects of the present invention, in which the battery is charged when a voltage is applied between the positive electrode and the negative electrode, and carbon dioxide is adsorbed to the negative electrode, and when the battery is discharged, the carbon dioxide adsorbed to the negative electrode is desorbed.

[0090] With this configuration, it is possible to more reliably perform the above-described charging while adsorbing carbon dioxide from a gas containing carbon dioxide, and desorbing the carbon dioxide during discharge.

[0091] A carbon dioxide adsorption battery according to an eighth aspect of the present invention is the carbon dioxide adsorption battery according to any one of the first to seventh aspects of the present invention, wherein the negative electrode is an electrode that adsorbs carbon dioxide by electrolytic reduction and desorbs carbon dioxide by electrolytic oxidation.

[0092] According to this configuration, it is possible to more reliably perform the above-described charging while adsorbing carbon dioxide from a gas containing carbon dioxide, and desorbing the carbon dioxide during discharge. This is believed to be due to the following reasons.

[0093] In the carbon dioxide adsorption battery, carbon dioxide is adsorbed to the negative electrode during charging. Specifically, when a voltage is applied between the positive electrode and the negative electrode such that the potential of the negative electrode is lower than the potential of the positive electrode, which is the voltage at which carbon dioxide is adsorbed to the negative electrode through an electrochemical reaction, the negative electrode adsorbs carbon dioxide through electrolytic reduction. Although the mechanism by which carbon dioxide is adsorbed is unclear as described above, during charging, oxygen in contact with the negative electrode and the negative electrode side of the electrolyte layer is reduced to a reduced form such as superoxide radical, which then binds to the negative electrode. It is believed that carbon dioxide is adsorbed to the negative electrode by the reduced form such as superoxide radical binding to carbon dioxide present around the negative electrode or dissolved in the electrolyte. Subsequently, when the battery is discharged, the carbon dioxide adsorbed to the negative electrode is desorbed from the negative electrode. Although the mechanism by which carbon dioxide is desorbed is unclear, it is believed that the discharge electrolytically oxidizes reductants such as superoxide radicals, returning them to the oxygen they were in before being electrolytically reduced, which prevents carbon dioxide from being adsorbed to the negative electrode by an electrochemical reaction, and the carbon dioxide adsorbed to the negative electrode is desorbed from the negative electrode. In this way, the carbon dioxide adsorption battery can more efficiently adsorb and desorb carbon dioxide. Therefore, the carbon dioxide adsorption battery can be charged while adsorbing carbon dioxide from a gas containing carbon dioxide, and can desorb the carbon dioxide during discharge in a short time, even at a low voltage.

[0094] A carbon dioxide adsorption battery according to a ninth aspect of the present invention is the carbon dioxide adsorption battery according to any one of the first to eighth aspects of the present invention, wherein the negative electrode is made of a conductive material including at least one selected from the group consisting of graphite, carbon nanotubes, and carbon fibers.

[0095] With this configuration, carbon dioxide is more easily adsorbed onto the negative electrode from a gas containing carbon dioxide, and the state of charge can be maintained longer. Therefore, the carbon dioxide adsorption battery can adsorb more carbon dioxide from a gas containing carbon dioxide, charge while this adsorption occurs, and desorb the carbon dioxide during discharge in a short time even at a low voltage. This is thought to be because the negative electrode not only allows a voltage to be more suitably applied between the negative electrode and the positive electrode, but also allows carbon dioxide to more suitably permeate.

[0096] A carbon dioxide adsorption battery according to a tenth aspect of the present invention is the carbon dioxide adsorption battery according to any one of the first to ninth aspects of the present invention, wherein the porous electrode is made of a porous material containing at least one selected from the group consisting of conductive ceramics, graphite, carbon nanotubes, activated carbon, and carbon fibers.

[0097] This configuration allows the battery to efficiently adsorb carbon dioxide from a carbon dioxide-containing gas during charging and desorb the carbon dioxide during discharge, and further allows the battery to be driven at a lower voltage (i.e., lower power consumption). This is thought to be due to the fact that charge compensation without electrochemical reaction can be more suitably performed at the positive electrode.

[0098] A charge / discharge device according to an eleventh aspect of the present invention is a charge / discharge device including two or more carbon dioxide adsorption batteries according to any one of the first to tenth aspects of the present invention.

[0099] According to this configuration, a charging / discharging device including the carbon dioxide adsorption battery can be provided. Furthermore, by including two or more carbon dioxide adsorption batteries, the charging / discharging device can alternately charge and discharge each of the carbon dioxide adsorption batteries. Specifically, first, one of the carbon dioxide adsorption batteries (first battery) is charged. Then, the other carbon dioxide adsorption battery (second battery) connected to the first battery can be charged by discharging the first battery. Then, the first battery can be charged by discharging the second battery. Thus, by once charging the first battery, the charging / discharging device can be used as a charging / discharging device that can alternately charge and discharge the first battery and the second battery. This makes the charging / discharging device highly energy-efficient. Furthermore, the charging / discharging device can alternately adsorb and desorb carbon dioxide from the first battery and the second battery, and can separate carbon dioxide from a carbon dioxide-containing gas in a short time, even at a low voltage.

[0100] According to the present invention, it is possible to provide a carbon dioxide adsorption battery that can be charged while adsorbing carbon dioxide from a gas containing carbon dioxide, and desorb the carbon dioxide during discharge in a short time even at a low voltage. Furthermore, according to the present invention, it is possible to provide a charge / discharge device that includes the carbon dioxide adsorption battery.

[0101] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

[0102] Example 1 <Fabrication of Carbon Dioxide Adsorption Battery> A carbon dioxide adsorption battery having the structure shown in FIGS. 1 and 2 was fabricated by the following procedure.

[0103] (Electrolyte Layer) 6.5 g of poly(vinylidene fluoride-co-hexafluoropropylene) (Sigma-Aldrich) was added to 100.0 g of dimethylformamide (Fujifilm Wako Pure Chemical Industries, Ltd.) and dissolved by stirring at 80 ° C. for 3 hours. Next, 12.9 g of an ionic liquid [1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (non-volatile) (Sigma-Aldrich emimFSI)], which is an electrolyte capable of dissolving carbon dioxide, was added to the resulting solution, heated to 40 ° C., and stirred and mixed for 3 hours. Using the liquid obtained in this way, a 500 μm thick liquid film was produced on a glass plate using an applicator and dried under reduced pressure at 60 ° C. for 8 hours. The dried film obtained by the drying was peeled off from the glass plate. By doing so, a dried film with a thickness of 100 μm was obtained. The obtained dry film was cut into a size of 30 mm length x 30 mm width and used as electrolyte layer-1. When the obtained electrolyte layer-1 was visually inspected, no minute holes (pinholes) were found.

[0104] (Positive electrode) Activated carbon (YP-50F manufactured by Kuraray Co., Ltd.), styrene-butadiene rubber (SBR) (TRD2001 manufactured by JSR Corporation), carboxymethyl cellulose (CMC) (Cellogen F-BSH manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and acetylene black (Denka Black manufactured by Denka Co., Ltd.) were mixed with water to give a ratio of activated carbon: SBR: CMC: acetylene black = 90: 3: 2: 5 (mass ratio) to obtain a slurry. The obtained slurry was applied to a 20 μm thick etched aluminum foil (manufactured by Hosen Co., Ltd.) using a bar coater, and then dried for 7 hours at 120 ° C. under a reduced pressure atmosphere using a glass tube oven to obtain a polarizable electrode-1 (an electrode in which a porous electrode and a current collector are integrated). That is, the layer formed on the etched aluminum foil (current collector) was a porous electrode. The BET specific surface area of ​​this porous electrode was calculated from the nitrogen adsorption isotherm obtained by measuring the nitrogen adsorption isotherm, and was found to be 1500 m ２ / g. The polarizable electrode-1 was cut into a plurality of pieces measuring 30 mm in length and 30 mm in width. The thickness of the obtained electrode (positive electrode) was 250 μm. 0.3 g of an ionic liquid [1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (non-volatile)] was added to the electrode (positive electrode). A conductive copper foil tape (used as a tab) was attached to one side of the etched aluminum foil of the electrode to which the ionic liquid had been added.

[0105] (Negative electrode) Carbon paper (GDL35BC manufactured by SGL Carbon Japan Co., Ltd.) was cut into multiple pieces measuring 30 mm long x 30 mm wide. The BET specific surface area of ​​this carbon paper (negative electrode) was calculated from the nitrogen adsorption isotherm obtained by measuring the nitrogen adsorption isotherm. ２ / g.

[0106] The negative electrode was prepared by attaching a conductive copper foil tape (used as a tab) to one side of the cut-out carbon paper.

[0107] (Separator) A vinylon separator (BFN manufactured by Kuraray Co., Ltd.) cut into a size of 30 mm length x 30 mm width was used as the separator.

[0108] (Flow path) A polytetrafluoroethylene resin plate was cut into a size of 50 mm length × 50 mm width × 5 mm thickness, and two holes were drilled at appropriate locations. A groove with a depth of 1 mm × length of 20 mm × width of 20 mm was dug in this cut-out resin plate to connect to the holes. This was used as a flow path.

[0109] (Carbon dioxide adsorption battery) The negative electrode, the electrolyte layer, the separator immersed in the ionic liquid, and the positive electrode immersed in the ionic liquid were laminated in this order, and the flow path was assembled on the negative electrode surface to produce a carbon dioxide adsorption battery having a structure as shown in Figures 1 and 2. During charging of the carbon dioxide adsorption battery, a power supply serving as a voltage application unit was connected to the conductive copper foil tape of the positive electrode and the conductive copper foil tape of the negative electrode, as shown in Figure 1. During discharging of the carbon dioxide adsorption battery, a resistor was connected to the conductive copper foil tape of the positive electrode and the conductive copper foil tape of the negative electrode, as shown in Figure 2.

[0110] Example 2 The same procedure as in Example 1 was carried out, except that a negative electrode (carbon sheet) described below was used as the negative electrode instead of the carbon paper.

[0111] Graphite (UP-20-α manufactured by Nippon Graphite Industries Co., Ltd.), acetylene black (Denka Black manufactured by Denka Co., Ltd.), and polytetrafluoroethylene (polytetrafluoroethylene "6J" manufactured by Mitsui Chemours Fluoroproducts Co., Ltd.) as a binder were weighed and kneaded to a graphite:acetylene black:binder ratio of 81:9:10. In order to further enhance the uniformity of the kneaded product obtained by the kneading, the kneaded product was cut into flakes of 1 mm square or less, and the cut flake-shaped kneaded product was placed in a coin-molding mold and pressed at 30 MPa to obtain a coin-shaped molded product. The obtained molded product was molded into a sheet having a thickness of 160 μm ± 5% (± 8 μm) using a roll press (manufactured by Daito Seisakusho Co., Ltd.). The carbon sheet thus obtained was cut into a predetermined size (30 mm × 30 mm). The BET specific surface area of ​​this carbon sheet (negative electrode) was calculated from the nitrogen adsorption isotherm obtained by measuring the nitrogen adsorption isotherm. ２ The negative electrode was prepared by attaching a conductive copper foil tape (used as a tab) to one surface of the cut-out carbon sheet.

[0112] Example 3 The same procedure as in Example 1 was carried out, except that a positive electrode described below was used as the positive electrode instead of the positive electrode obtained using the activated carbon (YP-50F).

[0113] Activated carbon (Kuraray Co., Ltd., K ... The BET specific surface area of ​​this porous electrode was calculated from the nitrogen adsorption isotherm obtained by measuring the nitrogen adsorption isotherm, and was found to be 900 m ２ / g. The polarizable electrode-2 was cut into a plurality of pieces measuring 30 mm in length and 30 mm in width. The thickness of the obtained electrode (positive electrode) was 250 μm. 0.2 g of an ionic liquid [1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (non-volatile)] was added to the electrode (positive electrode). A conductive copper foil tape (used as a tab) was attached to one side of the etched aluminum foil of the electrode to which the ionic liquid had been added.

[0114] Example 4 The procedure was the same as in Example 3, except that the negative electrode (carbon sheet) in Example 2 was used as the negative electrode instead of the carbon paper.

[0115] Example 5 The same procedure as in Example 1 was carried out, except that the polarizable electrode-1 was replaced with a positive electrode described below.

[0116] Activated carbon (YP-80F manufactured by Kuraray Co., Ltd.), styrene-butadiene rubber (SBR) (TRD2001 manufactured by JSR Corporation), carboxymethyl cellulose (CMC) (Cellogen F-BSH manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), and acetylene black (Denka Black manufactured by Denka Co., Ltd.) were mixed with water to a mass ratio of activated carbon:SBR:CMC:acetylene black = 90:3:2:5 to obtain a slurry. The obtained slurry was applied to a 20 μm thick etched aluminum foil (manufactured by Hosen Co., Ltd.) using a bar coater, and then dried for 7 hours at 120 ° C. under a reduced pressure atmosphere using a glass tube oven to obtain a polarizable electrode-3 (an electrode in which a porous electrode and a current collector are integrated). That is, the layer formed on the etched aluminum foil (current collector) was a porous electrode. The BET specific surface area of ​​this porous electrode was calculated from the obtained adsorption isotherm by performing nitrogen adsorption isotherm measurement, and was found to be 2100 m ２ / g. The polarizable electrode-3 was cut into a plurality of pieces measuring 30 mm long x 30 mm wide. The thickness of the obtained electrode (positive electrode) was 250 μm. 0.3 g of an ionic liquid [1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (non-volatile)] was added to the electrode (positive electrode). A conductive copper foil tape (used as a tab) was attached to one side of the etched aluminum foil of the electrode to which the ionic liquid had been added.

[0117] Example 6 The same procedure as in Example 1 was carried out, except that an electrolyte layer (electrolyte layer-2) described below was used as the electrolyte layer instead of the electrolyte layer-1.

[0118] (Electrolyte Layer) 6.5 g of poly(vinylidene fluoride-co-hexafluoropropylene) (Sigma-Aldrich) was added to 100.0 g of dimethylformamide (Fujifilm Wako Pure Chemical Industries, Ltd.), and dissolved by stirring at 80° C. for 3 hours. Next, 12.0 g of the redox compound [poly(4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical)] (non-volatile) obtained by polymerizing the redox compound, 4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical (Tokyo Chemical Industry Co., Ltd.) as a monomer using a conventional anionic polymerization method, was added to the resulting solution, and the solution was dissolved by stirring at 80° C. for 3 hours. Next, 12.9 g of an ionic liquid [1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (non-volatile) (emimFSI manufactured by Sigma-Aldrich)], which is an electrolyte solution capable of dissolving carbon dioxide, was added to the obtained solution, heated to 40 ° C, and stirred and mixed for 3 hours. Using the liquid obtained in this way, a liquid film having a thickness of 500 μm was formed on a glass plate with an applicator and dried under reduced pressure at 60 ° C for 8 hours. The dried film obtained by the drying was peeled off from the glass plate. In this way, a dried film having a thickness of 100 μm was obtained. This obtained dried film was cut into a size of 30 mm length x 30 mm width and used as electrolyte layer-2. When the obtained electrolyte layer-2 was visually inspected, no small holes (pinholes) were observed.

[0119] Comparative Example 1 The procedure of Example 1 was repeated except that the polarizable electrode-1 used as the positive electrode in Example 1 was used as the negative electrode instead of the carbon paper.

[0120] Comparative Example 2 The same procedure as in Example 1 was carried out except that the polarizable electrode-2 was used as the positive electrode instead of the polarizable electrode-1, and the polarizable electrode-3 was used as the negative electrode instead of the carbon paper.

[0121] Comparative Example 3 The same procedure as in Example 1 was carried out, except that, instead of the polarizable electrode-1, carbon paper to which 1 g of an ionic liquid [1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (non-volatile)] was added was used as the positive electrode. Note that the BET specific surface area of ​​the carbon paper was 4 m as described above. ２ / g.

[0122] Comparative Example 4 The same procedure as in Example 1 was carried out except that the carbon sheet was used as the positive electrode instead of the polarizable electrode-1.

[0123] The positive and negative electrodes used in Examples 1 to 6 and Comparative Examples 1 to 4 are shown in Table 1.

[0124]

[0125] [Evaluation] The carbon dioxide adsorption battery was evaluated by the following evaluation method.

[0126] First, the carbon dioxide adsorption battery was placed in an environment at room temperature (28°C), and a gas bag filled with a mixed gas of carbon dioxide and air was attached to the hole in the flow path. A portable carbon dioxide concentration meter (CGP-19a manufactured by DKK-TOA Corporation) was installed inside the gas bag. An air pump was attached to the connection between the flow path and the gas bag, and the mixed gas was circulated through the flow path and the gas bag at a flow rate of 1 L / min. The mixed gas at the start of the test was adjusted to have a carbon dioxide concentration of 4000 ± 100 ppm. Then, by adjusting a charge / discharge tester (TOSCAT manufactured by Toyo Systems Co., Ltd.), the positive electrode was maintained at a potential 1.6 V higher than the negative electrode, and the battery was charged for 6 minutes. The carbon dioxide concentration in the gas bag after this charge was measured with the portable carbon dioxide concentration meter. Furthermore, after charging, the charge / discharge tester was adjusted to maintain a potential 0.8 V higher than the positive electrode, and the battery was discharged for 6 minutes. After this discharge, the concentration of carbon dioxide in the gas bag was measured using the portable carbon dioxide concentration meter.

[0127] The value obtained by subtracting the carbon dioxide concentration in the gas bag after charging from the carbon dioxide concentration in the gas bag before the test (before the test started - after charging) was taken as the absorption concentration. This means that the decrease in the carbon dioxide concentration in the gas bag after charging from the carbon dioxide concentration in the gas bag before the test started is thought to be due to the adsorption of carbon dioxide into the carbon dioxide adsorption battery, so the above value (before the test started - after charging) was taken as the absorption concentration.

[0128] The value obtained by subtracting the carbon dioxide concentration in the gas bag after charging from the carbon dioxide concentration in the gas bag after discharging (after discharging - after charging) was taken as the desorption concentration. This means that the increase in the carbon dioxide concentration in the gas bag after discharging, compared to the carbon dioxide concentration in the gas bag after charging, is thought to be due to the desorption from the carbon dioxide adsorption battery of the carbon dioxide absorbed into the carbon dioxide adsorption battery during charging, and therefore the above value (after discharging - after charging) was taken as the desorption concentration.

[0129] During discharge, the discharge electric energy was calculated from the current flowing through the charge / discharge test device, the voltage at that time, and the discharge time.

[0130] The results are shown in Table 2. Note that the BET specific surface area of ​​the porous electrode in Table 2 indicates the BET specific surface area of ​​the porous electrode when the positive electrode is provided with a porous electrode, and indicates the BET specific surface area of ​​the positive electrode when the positive electrode is not provided with a porous electrode. Also, the BET specific surface area of ​​the negative electrode in Table 2 indicates the BET specific surface area of ​​the porous electrode when the negative electrode is provided with a porous electrode, and indicates the BET specific surface area of ​​the negative electrode when the negative electrode is not provided with a porous electrode.

[0131]

[0132] As can be seen from Table 2, the BET specific surface area is 100 to 3000 m ２Carbon dioxide adsorption batteries (carbon dioxide adsorption batteries according to Examples 1 to 6) each comprising a positive electrode having a porous electrode with a specific surface area of ​​1.6 V / g, a gas-permeable negative electrode, and an electrolyte layer containing an electrolyte solution capable of dissolving carbon dioxide, in which the specific surface area of ​​the porous electrode was higher than that of the negative electrode, were able to preferably discharge after charging (preferably charge and discharge). In particular, carbon dioxide adsorption batteries (carbon dioxide adsorption batteries according to Examples 1 to 5) in which the electrolyte layer did not contain a redox compound were able to be charged even at a relatively low voltage such that the positive electrode was in a state where the potential was 1.6 V higher than the negative electrode, and were also able to be discharged after charging. Specifically, the carbon dioxide adsorption batteries according to Examples 1 to 6 each had a BET specific surface area of ​​100 to 3,000 m ２The discharge electrical energy was higher than when a positive electrode not equipped with a porous electrode having a capacitance of 0.01 / g was used (the carbon dioxide adsorption batteries according to Comparative Examples 3 and 4). This shows that the carbon dioxide adsorption batteries according to Examples 1 to 6 can be charged and discharged more suitably than the carbon dioxide adsorption batteries according to Comparative Examples 3 and 4. Furthermore, the carbon dioxide adsorption battery according to Example 6, which includes a redox compound in the electrolyte layer, was able to be discharged after charging even if it did not operate sufficiently at a relatively low voltage such that the positive electrode was at a potential 1.6 V higher than the negative electrode. Furthermore, the results of using the carbon dioxide adsorption batteries according to Examples 1 to 6 showed that the higher the ratio of the BET specific surface area of ​​the porous electrode to the BET specific surface area of ​​the negative electrode (BET specific surface area of ​​porous electrode / BET specific surface area of ​​negative electrode), the higher the discharge electrical energy. Furthermore, the carbon dioxide adsorption batteries according to Examples 1 to 6 had higher adsorption concentrations and desorption concentrations than those not equipped with the above-described configuration (the carbon dioxide adsorption batteries according to Comparative Examples 1 to 4). From this, it was found that the carbon dioxide adsorption batteries according to Examples 1 to 6 can adsorb carbon dioxide favorably even at the above-mentioned relatively low voltage, and can desorb the adsorbed carbon dioxide favorably by discharging. It is believed that the carbon dioxide adsorption batteries according to Comparative Examples 1 and 2 had a large specific surface area of ​​the negative electrode, which made it difficult for the CO2 adsorption reaction to occur. It is also believed that the carbon dioxide adsorption batteries according to Comparative Examples 3 and 4 had a small specific surface area of ​​the porous electrode, which made it difficult for charge compensation without an electrochemical reaction to occur. Therefore, it was found that the carbon dioxide adsorption batteries according to Examples 1 to 6, by having the above-mentioned configuration, can adsorb and desorb carbon dioxide in a short time by charging and discharging, even when charged at a relatively low voltage.

[0133] This application is based on Japanese Patent Application No. 2024-108929 filed on July 5, 2024, the contents of which are incorporated herein by reference.

[0134] In order to express the present invention, the present invention has been properly and sufficiently described through the embodiments in the above, but it should be recognized that those skilled in the art can easily change and / or improve the above-mentioned embodiments. Therefore, unless the changes or improvements made by those skilled in the art are at a level that causes departure from the scope of the claims described in the claims, such changes or improvements are interpreted as being included in the scope of the claims.

[0135] According to the present invention, there is provided a carbon dioxide adsorption battery that can adsorb carbon dioxide from a carbon dioxide-containing gas while charging and desorb the carbon dioxide during discharge in a short time even at a low voltage. Also, according to the present invention, there is provided a charge / discharge device that includes the carbon dioxide adsorption battery.

Claims

1. A battery comprising: a positive electrode; a negative electrode; an electrolyte layer disposed between the positive electrode and the negative electrode; and a flow path connected to the negative electrode, wherein the electrolyte layer contains an electrolyte solution capable of dissolving carbon dioxide; the negative electrode is an electrode that is permeable to gas; the positive electrode includes a porous electrode, and the porous electrode has a specific surface area of ​​100 to 3,000 m in terms of BET specific surface area. ２ / g and higher than the specific surface area of ​​the negative electrode.

2. The carbon dioxide adsorption battery according to claim 1, wherein the ratio of the BET specific surface area of ​​the porous electrode to the BET specific surface area of ​​the negative electrode is 10 to 3,000 times.

3. The carbon dioxide adsorption battery according to claim 1 or 2, further comprising a separator disposed between the positive electrode and the electrolyte layer.

4. The specific surface area of ​​the negative electrode is 0.1 to 200 m in terms of BET specific surface area. ２ The carbon dioxide adsorption battery according to any one of claims 1 to 3, wherein the carbon dioxide adsorption battery has a densitometric value of 0.1 / g.

5. The carbon dioxide adsorption battery according to any one of claims 1 to 4, wherein the porous electrode contains the electrolyte.

6. A carbon dioxide adsorption battery according to any one of claims 1 to 5, wherein the flow path is a flow path through which at least one of carbon dioxide adsorbed onto the negative electrode and carbon dioxide desorbed from the negative electrode can flow.

7. The carbon dioxide adsorption battery according to any one of claims 1 to 6, wherein when a voltage is applied between the positive electrode and the negative electrode, charging occurs and carbon dioxide is adsorbed to the negative electrode, and when discharging occurs, the carbon dioxide adsorbed to the negative electrode is desorbed.

8. The carbon dioxide adsorption battery according to any one of claims 1 to 7, wherein the negative electrode is an electrode that adsorbs carbon dioxide by electrolytic reduction and desorbs carbon dioxide by electrolytic oxidation.

9. The carbon dioxide adsorption battery according to any one of claims 1 to 8, wherein the negative electrode is made of a conductive material containing at least one material selected from the group consisting of graphite, carbon nanotubes, and carbon fibers.

10. The carbon dioxide adsorption battery according to any one of claims 1 to 9, wherein the porous electrode is made of a porous material containing at least one material selected from the group consisting of conductive ceramics, graphite, carbon nanotubes, activated carbon, and carbon fiber.

11. A charging / discharging device comprising two or more carbon dioxide adsorption batteries according to any one of claims 1 to 10.

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