Oxygen evolution electrode, electrochemical cell, and oxygen supply device

Abstract

Provided are an oxygen supply device that is leak-free and capable of generating oxygen with high efficiency, as well as an oxygen evolution electrode and an electrochemical cell for achieving the oxygen supply device. The oxygen evolution electrode used in this oxygen supply device contains a metal oxide, a metal ion-conductive solid electrolyte, an oxygen evolution catalyst, and an electron-conducting auxiliary agent, and the oxygen evolution catalyst is supported on the metal oxide.

Description

Oxygen generating electrode, electrochemical cell, and oxygen supply device

[0001] This disclosure relates to an oxygen generating electrode, an electrochemical cell, and an oxygen supply device.

[0002] Oxygen supply devices that supply oxygen to the outside are known. For example, Patent Document 1 (Japanese Patent Application Publication No. 2023-011956) discloses an oxygen generating device that includes a second battery having a positive electrode which is an air electrode, a negative electrode containing zinc, and an electrolyte containing an aqueous alkali metal hydroxide solution. In this second battery, it is described that oxygen is generated at the positive electrode which has a shape such as a porous body, and zinc is deposited at the negative electrode based on a reduction reaction of zinc ions. Patent Document 2 (U.S. Patent Application Publication No. 2023 / 0386523) discloses a metal-air battery that generates oxygen, and it is described that this air battery has a metal as a first electrode, a metal oxide as a second electrode, and a liquid or solid electrolyte.

[0003] Japanese Patent Publication No. 2023-011956, U.S. Patent Application Publication No. 2023 / 0386523

[0004] However, in oxygen generators such as the one disclosed in Patent Document 1, an alkali metal hydroxide aqueous solution is used as the electrolyte, which can cause the electrolyte to leak from the battery and potentially have adverse effects on peripheral equipment and the human body. Furthermore, conventional oxygen supply devices have insufficient oxygen generation capacity, and there is a need for the development of oxygen generation electrodes and oxygen supply devices that can generate oxygen more efficiently.

[0005] The present inventors have now discovered that by configuring the oxygen generation electrode used in an oxygen supply device in which the oxygen generation catalyst is supported on a metal oxide, it is possible to provide an oxygen supply device that can generate oxygen efficiently without leakage.

[0006] Therefore, the object of the present invention is to provide an oxygen supply device that can generate oxygen with high efficiency without leakage, as well as an oxygen generation electrode and an electrochemical cell for realizing this.

[0007] According to the present disclosure, the following aspects are provided. [Aspect 1] An oxygen generation electrode used in an oxygen supply device, wherein the oxygen generation electrode includes a metal oxide, a metal ion-conductive solid electrolyte, an oxygen generation catalyst, and an electron conduction assistant, and the oxygen generation catalyst is supported on the metal oxide. [Aspect 2] The oxygen generation electrode according to Aspect 1, wherein the metal oxide is a lithium oxide and the metal ion-conductive solid electrolyte is a lithium ion-conductive solid electrolyte. [Aspect 3] The oxygen generation electrode according to Aspect 2, wherein the lithium oxide is Li ２ O ２ and / or Li ２ O. [Aspect 4] The oxygen generation electrode according to any one of Aspects 1 to 3, wherein the oxygen generation catalyst includes at least one selected from the group consisting of RuO ２ , MnO ２ , Co ３ O ４ , and perovskite-type oxides. [Aspect 5] The oxygen generation electrode according to Aspect 4, wherein the perovskite-type oxide has a composition represented by LaNi １－ｘ－ｙ Cu ｘ Fe ｙ O ３－δ (where x > 0, y > 0, x + y < 1, 0 ≤ δ ≤ 0.4). [Aspect 6] The oxygen generation electrode according to any one of Aspects 1 to 5, wherein the electron conduction assistant is conductive carbon. [Aspect 7] The oxygen generation electrode according to any one of Aspects 1 to 6, wherein at least a part of the oxygen generation catalyst exists in the form of a compound of the oxygen generation catalyst and the metal oxide. [Aspect 8] The metal oxide is Li ２ O, the oxygen generation catalyst is MnO ２ or RuO ２ , and the compound is Li ２ MnO ３ or Li ２ RuO ３The oxygen generating electrode according to Embodiment 7. [Embodiment 9] An electrochemical cell comprising: a positive electrode layer containing the oxygen generating electrode according to any one of Embodiments 1 to 7; a negative electrode layer on which a metal derived from the metal oxide can be deposited, alloyed with the metal, or adsorbed; and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer, the solid electrolyte layer being composed of a metal ion conductive solid electrolyte. [Embodiment 10] The electrochemical cell according to Embodiment 9, wherein the metal ion conductive solid electrolyte contained in the oxygen generating electrode and the metal ion conductive solid electrolyte constituting the solid electrolyte layer are made of the same material. [Embodiment 11] The electrochemical cell according to Embodiment 9 or 10, wherein the negative electrode layer and the solid electrolyte layer are adjacent to each other in such a way that a space is formed between them that allows for the deposition of the metal. [Aspect 12] The negative electrode layer is made of In, Al, Sn, C, Si, Ca, Sr, Ba, Rh, Ir, Pd, Pt, Au, Zn, Ga, Ge, Pb, Sb, Bi, Cu, stainless steel, SiO, TiO ２ Li ４ Ti ５ O １２ MnO ２ ,CuO,Fe ２ O ３ CuF ２ FeF ２ FeF ３ and AlF ３ An electrochemical cell according to any one of embodiments 9 to 11, comprising at least one selected from the group consisting of [Aspect 13] An electrochemical cell according to any one of embodiments 9 to 12, wherein the metal ion conductive solid electrolyte constituting the solid electrolyte layer comprises a fluoride. [Aspect 14] The fluoride comprises Li ３ AlF ６ An electrochemical cell according to embodiment 13, which includes the fluoride Li ３ AlF ６ and Li ２ SiF ６An electrochemical cell according to embodiment 14, which is a mixture of [Aspect 16] An oxygen supply device comprising: an electrochemical cell according to any one of embodiments 9 to 15; and an outer casing having an internal space in which the electrochemical cell is housed, wherein at least a part of the outer casing has a function or structure that allows oxygen to permeate. [Aspect 17] An oxygen supply device according to embodiment 16, further comprising a positive electrode current collector layer disposed between the outer casing and the positive electrode layer, and / or a negative electrode current collector layer disposed between the outer casing and the negative electrode layer.

[0008] This is a schematic cross-sectional view conceptually showing an electrochemical cell using the oxygen evolution electrode of the present invention. This is a schematic cross-sectional view showing an example of an oxygen supply device using the oxygen evolution electrode of the present invention. This is a schematic cross-sectional view conceptually showing the state in which the oxygen evolution catalyst is supported on a metal oxide within the oxygen evolution electrode. This is a perspective view showing an example of a coin-shaped oxygen supply device. This is the X-ray diffraction profile of the oxygen evolution electrode fabricated in Example 2. This is the X-ray diffraction profile of the oxygen evolution electrode fabricated in Example 17. This is the X-ray diffraction profile of the oxygen evolution electrode fabricated in Example 19. These are the X-ray diffraction profiles of the oxygen evolution electrodes fabricated in Example 23 (upper panel) and Example 27 (lower panel). Li is used as the metal oxide. ２ O, MnO as an oxygen evolution catalyst ２ These are the X-ray diffraction profiles of the mixed powder (top), the supported powder treated under condition A (middle), and the supported powder treated under condition B (bottom) when using [the specified method].

[0009] The oxygen generation electrode is an electrode (positive electrode) in an oxygen supply device that can generate oxygen by an electrochemical reaction. Figure 1 conceptually shows an electrochemical cell 10 equipped with an oxygen generation electrode 12, while Figure 2 shows an example of an oxygen supply device 20 equipped with an oxygen generation electrode 12 or an electrochemical cell 10. The oxygen generation electrode 12 includes a metal oxide, a metal ion conductive solid electrolyte, an oxygen generation catalyst, and an electron conduction aid. Within the oxygen generation electrode 12, as conceptually shown in Figure 3, the oxygen generation catalyst 12b is supported on the metal oxide 12a. In this way, by configuring the oxygen generation electrode 12 used in the oxygen supply device 20 so that the oxygen generation catalyst 12b is supported on the metal oxide 12a, it is possible to provide an oxygen supply device 20 that can generate oxygen with no leakage and high efficiency, as well as an oxygen generation electrode 12 and an electrochemical cell 10 to realize this.

[0010] In other words, as mentioned above, in oxygen generators such as the one disclosed in Patent Document 1, an alkali metal hydroxide aqueous solution is used as the electrolyte, which can cause the electrolyte to leak from the battery and potentially have adverse effects on peripheral equipment and the human body. Furthermore, conventional oxygen supply devices have insufficient oxygen generation capacity, and there is a need for the development of oxygen generation electrodes and oxygen supply devices that generate oxygen more efficiently. These problems are successfully solved according to the present invention. Specifically, in the electrochemical cell 10 using the oxygen generation electrode 12, a solid electrolyte layer composed of a metal ion conductive solid electrolyte can be used instead of an electrolyte (i.e., an all-solid-state electrochemical cell configuration can be adopted), thus realizing an oxygen supply device 20 without liquid leakage. Furthermore, by adopting a configuration in which an oxygen generation catalyst 12b is supported on a metal oxide 12a as the oxygen generation electrode 12, oxygen can be generated with high efficiency, that is, the amount of oxygen generated per unit time can be improved. The mechanism is not entirely clear, but it is presumed to be as follows. In other words, it is presumed that the above configuration improves the adhesion between the metal oxide 12a and the oxygen evolution catalyst 12b, thereby reducing the charge transfer resistance in the oxygen evolution reaction and allowing the reaction to proceed more efficiently, and that the increased adhesion area between the metal oxide 12a and the oxygen evolution catalyst 12b contributes to an improvement in the amount of oxygen generated.

[0011] As described above, the oxygen-evolving electrode 12 includes a metal oxide 12a, a metal ion-conducting solid electrolyte, an oxygen-evolving catalyst 12b, and an electron conduction aid. Each component will be described in detail below.

[0012] The metal oxide 12a is not particularly limited as long as it is an oxide capable of releasing oxygen through a reduction reaction catalyzed by the oxygen-evolving catalyst 12b, but preferred examples include lithium oxide (e.g., Li ２ O ２ and / or Li ２ O), potassium oxide (e.g., K ２ O ２ and / or K ２ O), sodium oxide (e.g., Na ２ O ２ and / or Na ２O), copper oxides (e.g., CuO and / or Cu ２ O), and silver oxides (e.g., Ag ２ O ２ and / or Ag ２ Examples include O), and more preferably lithium oxide. Lithium oxide is lithium peroxide (Li ２ O ２ ) and / or lithium oxide (Li ２ It is preferable that it be O.

[0013] The content of metal oxide 12a in the oxygen-generating electrode 12 is preferably 10 to 90 parts by volume, more preferably 20 to 80 parts by volume, and even more preferably 40 to 70 parts by volume, when the total amount of metal oxide 12a and metal ion-conducting solid electrolyte contained in the oxygen-generating electrode 12 is taken as 100 parts by volume.

[0014] The oxygen evolution catalyst 12b is not particularly limited, and any catalyst capable of promoting oxygen evolution from the metal oxide 12a may be used. A preferred example of the oxygen evolution catalyst 12b is RuO ２ MnO ２ Co ３ O ４ Examples include perovskite-type oxides and combinations thereof, and more preferably MnO ２ Co ３ O ４ These include perovskite oxides and combinations thereof. A preferred example of a perovskite oxide is LaNi １－ｘ－ｙ Cu ｘ Fe ｙ O ３－δOne example is a material having a composition represented by the formula (wherein x > 0, y > 0, x + y < 1, 0 ≤ δ ≤ 0.4) (hereinafter sometimes referred to as LNFCu). In this composition, it is preferable that 0 < x ≤ 0.5, more preferably 0.01 ≤ x ≤ 0.5, and even more preferably 0.05 ≤ x ≤ 0.30. It is also preferable that 0 < y ≤ 0.3, and more preferably 0.01 ≤ y ≤ 0.3. LNFCu can preferably be produced by firing a raw material containing La, Ni, Cu, and Fe, where the molar ratio of La, Ni, Cu, and Fe is La:Ni:Cu:Fe = 1:(1-x-y):x:y (where x > 0, y > 0, x + y < 1) at a temperature of 1200°C or lower. This production method may include preparing a raw material containing La, Ni, Cu, and Fe in the above ratios. The raw materials used in the calcination process may be obtained by mixing the above-mentioned metal oxide powders and / or hydroxide powders, or by a coprecipitation method or liquid-phase synthesis method using metal alkoxides or metal nitrates as starting materials. The preferred ranges for x, y, and δ are as described above. Ni and Cu are easily reduced in air and at high temperatures. Therefore, in the production of LNFCu, in order to adjust δ to a preferred range, the calcination process is preferably carried out at 1200°C or below, and more preferably in an oxygen atmosphere and at 1200°C or below. The calcination process may be considered as a single process, or it may include two or more heat treatments with different temperature conditions. In at least one of these processes, the above-mentioned raw materials may be heat-treated at a temperature of 1100°C or above. The calcination process may include a heat treatment set at a temperature of less than 1100°C. In any of the heat treatments, the temperature can be set to 1200°C or below. Although Fe has relatively low reactivity, a single-phase perovskite structure can be easily obtained by heat-treating the raw material at 1100°C or higher. Alternatively, a calcination step may be performed before the firing process, in which the raw material is calcined at 1100°C or higher. If calcination is performed, the temperature in the firing process may be less than 1100°C. The calcination step may also be performed at 1200°C or lower. However, the firing temperature conditions, firing time, etc. may be appropriately changed depending on the particle size of the raw material and other conditions.

[0015] As described above, the oxygen-evolving catalyst 12b is supported on the metal oxide 12a. Typically, the oxygen-evolving catalyst 12b and the metal oxide 12a are in the form of particles, and it is preferable that the particles of the oxygen-evolving catalyst 12b are supported on the surface of the particles of the metal oxide 12a, as shown in Figure 3. Therefore, it is desirable that the particle size of the metal oxide 12a be larger than the particle size of the oxygen-evolving catalyst 12b, but it is not limited to this, and the particle size of the metal oxide 12a may be about the same as the particle size of the oxygen-evolving catalyst 12b, or it may be smaller than the particle size of the oxygen-evolving catalyst 12b. Also, the metal oxide 12a is not limited to the particle form, but may be in bulk form. In the state in which the oxygen-evolving catalyst 12b is supported on the metal oxide 12a, it is preferable that the oxygen-evolving catalyst 12b is chemically or physically bonded to the metal oxide 12a, rather than being simply a mixture of the oxygen-evolving catalyst 12b and the metal oxide 12a. Therefore, the method for supporting the oxygen-evolving catalyst 12b on the metal oxide 12a is not particularly limited as long as it brings about a chemical or physical bond between the oxygen-evolving catalyst 12b and the metal oxide 12a, but a method of compounding the mixed powder of the metal oxide 12a and the oxygen-evolving catalyst 12b using pebbles is preferred. Such methods include, for example, mechanical milling using a planetary ball mill, ball mill, bead mill, vibratory mill, attritor, etc. Another example of a supporting method is the use of a device used for bonding particles together. Examples of such devices include Novilta (registered trademark) (manufactured by Hosokawa Micron) and Hybridizer (manufactured by Nara Machine Works).

[0016] The content of the oxygen evolution catalyst 12b in the oxygen evolution electrode 12 is preferably 3 to 35 parts by volume, more preferably 5 to 30 parts by volume, and even more preferably 10 to 20 parts by volume, when the total amount of metal oxide 12a and metal ion conductive solid electrolyte contained in the oxygen evolution electrode 12 is 100 parts by volume.

[0017] As mentioned above, the oxygen evolution catalyst 12b is supported on the metal oxide 12a, but depending on the support treatment conditions (for example, rotation speed and treatment time in the case of mechanical milling), the oxygen evolution catalyst 12b may react with the metal oxide 12a to form a compound (typically a composite metal oxide). Therefore, at least a portion of the oxygen evolution catalyst 12b may exist in the form of a compound of the oxygen evolution catalyst 12b and the metal oxide 12a. Typically, this compound is supported on the metal oxide 12a. This compound is thought to function as both an oxide capable of releasing oxygen (oxygen source) and a catalyst capable of promoting oxygen evolution. Therefore, this compound can be used as both a metal oxide 12a and an oxygen evolution catalyst 12b. A preferred example of such a compound is Li ２ MnO ３ (Li ２ O and MnO ２ Compounds with Li ２ RuO ３ (Li ２ O and RuO ２ Examples include composite metal oxides such as compounds with Li. ２ It is O, and the oxygen evolution catalyst 12b is MnO ２ or RuO ２ The above compound is Li ２ MnO ３ or Li ２ RuO ３ It is preferable that this is the case. The presence of the composite metal oxide (as well as the metal oxide 12a and oxygen evolution catalyst 12b) can be confirmed using known analytical methods such as X-ray diffraction (XRD). Examples of XRD equipment include the D2 PHASER manufactured by Bruker AXS and the RINT-TTR III manufactured by Rigaku Corporation.

[0018] The metal ion conductive solid electrolyte is not particularly limited as long as it is a solid electrolyte capable of conducting metal ions released from the metal oxide 12a in conjunction with oxygen evolution (reduction reaction). Therefore, preferred examples of metal ion conductive solid electrolytes include lithium ion conductive solid electrolytes, potassium ion conductive solid electrolytes, sodium ion conductive solid electrolytes, copper ion conductive solid electrolytes, and silver ion conductive solid electrolytes, with lithium ion conductive solid electrolytes being more preferred. Examples of lithium ion conductive solid electrolytes include oxide-based inorganic lithium ion conductive solid electrolytes, sulfide-based inorganic lithium ion conductive solid electrolytes, halide-based inorganic lithium ion conductive solid electrolytes, and organic lithium ion conductive electrolytes. Examples of oxide-based inorganic lithium ion conductive solid electrolytes include NASICON-type solid electrolytes, garnet-type solid electrolytes, and perovskite-type solid electrolytes. Examples of sulfide-based inorganic lithium ion conductive solid electrolytes include argyrodite-type solid electrolytes and thiolysicone-type solid electrolytes. Sulfide-based inorganic lithium-ion conductive solid electrolytes may be crystalline or amorphous. An example of a halide-based inorganic lithium-ion conductive solid electrolyte is an anti-perovskite type solid electrolyte. Furthermore, halide-based inorganic lithium-ion conductive solid electrolytes may be crystalline or amorphous. An example of an organic lithium-ion conductive electrolyte is a polyethylene oxide compound. Furthermore, organic lithium-ion conductive electrolytes may be intrinsic polymers or gel polymers.

[0019] A preferred metal ion-conductive solid electrolyte is a halide-based inorganic lithium ion-conductive solid electrolyte, and among halides, fluoride is particularly preferred. That is, the metal ion-conductive solid electrolyte preferably contains fluoride. The fluoride-based solid electrolyte has the merit of having a good balance between chemical stability and deformability against volume change. When used in an oxygen supply device 20 having an oxygen generation electrode 12 or the like, since the metal oxide 12a decomposes and / or disappears, it can be said that the volume change of the electrode is large. In that case, since the solid electrolyte containing fluoride has excellent deformability, it is considered that it can follow the volume change of the electrode, thereby maintaining the interfacial adhesion between the electrode and the solid electrolyte. In the case of a lithium ion-conductive solid electrolyte, this fluoride is Li ３ MF ６ (where M is an element that becomes a trivalent cation), and preferably contains a compound having a composition represented by, more preferably Li ３ AlF ６ (hereinafter sometimes referred to as LAF). Further, this fluoride is a mixture of a compound having a composition represented by Li ３ MF[[ID=eleven]] ６ (where M is an element that becomes a trivalent cation) and Li ２ SiF ６ (hereinafter sometimes referred to as LSF) is even more preferred. In this case, when Li ３ MF ６ and Li ２ SiF ６ are mixed so that the molar ratio is (1 - x): x (where 0 < x < 1), the above mixture is Li ３－ｘ M １－ｘ Si ｘ F ６It is represented by the following compositional formula. Considering measurement errors and the like, when the molar ratio of Li:M:Si:F is a:b:c:d, if the relational expressions of 0.9(3−x)≤a≤1.1(3−x), 0.9(1−x)≤b≤1.1(1−x), 0.9x≤c≤1.1x, and 5.4≤d≤6.6 are satisfied, it can be regarded as a component represented by the above compositional formula. In the above relational expressions, it is preferable that 0.05≤x≤0.8, and more preferably 0.05≤x≤0.6. Thereby, the lithium ion conductivity can be further improved. As described above, the lithium ion conductive solid electrolyte is Li ３ AlF ６ preferably contains, and more preferably Li ３ AlF ６ and Li ２ SiF ６ is a mixture of. Li ３ AlF ６ and Li ２ SiF ６ The mixture of is considered to have a higher lithium ion conductivity than elemental Li ３ AlF ６ . And in terms of molar ratio, Li ３ AlF ６ :Li ２ SiF ６ is preferably 0.95:0.05 to 0.2:0.8, more preferably 0.95:0.05 to 0.4:0.6, and even more preferably 0.9:0.1 to 0.6:0.4. 39>

[0019] The content of the metal ion conductive solid electrolyte in the oxygen generation electrode 12 is preferably 10 to 90 parts by volume, more preferably 20 to 80 parts by volume, and even more preferably 30 to 6 parts by volume, when the total amount of the metal oxide 12a and the metal ion conductive solid electrolyte contained in the oxygen generation electrode 12 is 100 parts by volume.

[0021] The electron conduction aid contained in the oxygen generation electrode 12 is not particularly limited as long as it is a conductive material, but is preferably a metal and / or conductive carbon, and more preferably conductive carbon. Examples of metals include aluminum, titanium, gold, silver, copper, platinum, chromium, nickel, and combinations thereof. The metal may also include alloys, an example of which is stainless steel. Examples of conductive carbons include acetylene black, carbon black, carbon nanofiber (CNF), carbon fiber (e.g., VGCF® (Vapor Grown Carbon Fiber)), graphite, and combinations thereof.

[0022] The content of the electron conduction aid in the oxygen generation electrode 12 is preferably 2 to 50 parts by volume, more preferably 3 to 30 parts by volume, and even more preferably 5 to 20 parts by volume, when the total amount of metal oxide 12a and metal ion conductive solid electrolyte contained in the oxygen generation electrode 12 is 100 parts by volume.

[0023] As shown in Figure 1 of the electrochemical cell, the oxygen-evolving electrode 12 can be incorporated into the electrochemical cell 10 as the positive electrode layer 12. The electrochemical cell 10 may comprise the positive electrode layer 12 containing the oxygen-evolving electrode, the negative electrode layer 14, and the solid electrolyte layer 16 interposed between the positive electrode layer 12 and the negative electrode layer 14. The negative electrode layer 14 may be an electrode capable of depositing, alloying with, or adsorbing metal derived from the metal oxide 12a. The solid electrolyte layer 16 may be composed of a metal ion-conducting solid electrolyte. Since such a configuration is an all-solid-state electrochemical cell that does not contain an electrolyte, it is possible to realize an oxygen supply device 20 without liquid leakage.

[0024] In the electrochemical cell 10 (and the oxygen supply device 20 described later), when lithium oxide is used as the metal oxide 12a, the following formula is obtained in the positive electrode layer 12: Li ２ O ｘ → 2Li ＋ + 2e － + x / 2O ２The reaction shown by ↑ (where x is 1 or 2) proceeds. That is, the metal oxide is reduced in the positive electrode layer 12. As a result, oxygen is generated in the positive electrode layer 12, and metal ions and electrons are released. For example, MnO is used as the oxygen generation catalyst 12b. ２ Li as metal oxide 12a ２ Reacts with O to form a composite metal oxide (Li ２ MnO ３ When forming the positive electrode layer 12, Li ２ MnO ３ The following formula: 2Li ２ MnO ３ → 4Li ＋ + 4e － + MnO ２ + O ２ The reaction shown above is thought to proceed. Then, metal ions reach the negative electrode layer 14 via the metal ion conductive solid electrolyte constituting the solid electrolyte layer 16, and electrons reach the negative electrode layer 14 via the external power supply and wiring. For example, in the negative electrode layer 14, the following equation: Li ＋ + e － → The reaction indicated by Li proceeds, and metal ions and electrons combine to precipitate a metal derived from the metal oxide 12a. Alternatively, in the negative electrode layer 14, alloying of the metal derived from the metal oxide 12a with the metal constituting the negative electrode layer 14 may proceed, or intercalation of the metal derived from the metal oxide 12a may proceed.

[0025] In other words, the negative electrode layer 14 can be an electrode on which metal derived from the metal oxide 12a can be deposited, alloyed with metal derived from the metal oxide 12a, or adsorbed metal derived from the metal oxide 12a. From these viewpoints, the negative electrode layer 14 can be made of In, Al, Sn, C, Si, Ca, Sr, Ba, Rh, Ir, Pd, Pt, Au, Zn, Ga, Ge, Pb, Sb, Bi, Cu, stainless steel, SiO, TiO ２ Li ４ Ti ５ O １２ MnO ２ ,CuO,Fe ２ O ３ CuF ２ FeF ２ FeF３ and AlF ３ Preferably, it includes at least one selected from the group consisting of the following. Examples of electrode materials on which metal derived from metal oxide 12a can be deposited include Cu and stainless steel. Examples of electrode materials that can alloy with metal derived from metal oxide 12a or that can intercalate metal derived from metal oxide 12a include In, Al, Sn, C, Si, Ca, Sr, Ba, Rh, Ir, Pd, Pt, Au, Zn, Ga, Ge, Pb, Sb, Bi, SiO, TiO ２ Li ４ Ti ５ O １２ MnO ２ ,CuO,Fe ２ O ３ CuF ２ FeF ２ FeF ３ and AlF ３ Examples include, preferably In, Al, Sn, C, Si, Ca, Zn, Pb, Sb, Bi, SiO, TiO ２ Li ４ Ti ５ O １２ ,CuO,Fe ２ O ３ CuF ２ FeF ２ FeF ３ and AlF ３ More preferably In, Al, Sn, C, Si, TiO ２ Li ４ Ti ５ O １２ ,CuO,Fe ２ O ３ FeF ２ FeF ３ and AlF ３ These are some examples.

[0026] The solid electrolyte layer 16 may be composed of a metal ion conductive solid electrolyte. The metal ion conductive solid electrolyte is not particularly limited as long as it is a solid electrolyte capable of conducting metal ions released from the metal oxide 12a in connection with oxygen evolution (reduction reaction), similar to the metal ion conductive solid electrolyte described above with respect to the oxygen evolution electrode 12. Therefore, the description of the metal ion conductive solid electrolyte described above with respect to the oxygen evolution electrode 12 also applies to the solid electrolyte layer 16. Accordingly, the metal ion conductive solid electrolyte constituting the solid electrolyte layer 16 preferably contains a fluoride, and more preferably the fluoride is Li ３ AlF ６ It contains, and more preferably the fluoride is Li ３ AlF ６ and Li ２ SiF ６ It is a mixture of the above. Fluoride-based solid electrolytes have the advantage of a good balance between chemical stability and deformability against volume changes. When using an oxygen supply device 20 having an oxygen generation electrode 12, the metal oxide 12a decomposes and / or disappears, so the volume change of the electrode is large. In that case, since the solid electrolyte containing fluoride has excellent deformability, it can follow the volume change of the electrode, and thereby it is thought that the interfacial adhesion between the electrode and the solid electrolyte can be maintained. The metal ion conductive solid electrolyte contained in the positive electrode layer 12 (oxygen generation electrode) and the metal ion conductive solid electrolyte constituting the solid electrolyte layer 16 may be the same material or different materials, but preferably they are the same material.

[0027] As described above, the negative electrode layer 14 may be capable of depositing metal derived from the metal oxide 12a. In this case, it is preferable that the negative electrode layer 14 and the solid electrolyte layer 16 are adjacent to each other in such a way that a space is formed between them that allows for the deposition of metal. That is, although the negative electrode layer 14 and the solid electrolyte layer 16 are adjacent to each other, it is preferable that the negative electrode layer 14 and / or the solid electrolyte layer 16 are displaced as metal is deposited, forming a space that is filled with deposited metal on at least a part of the adjacent surface.

[0028] As shown in Figure 2 of the oxygen supply device, the oxygen generation electrode 12 or electrochemical cell 10 can be incorporated into the oxygen supply device 20. The oxygen supply device 20 comprises the electrochemical cell 10 and an outer casing 22. The outer casing 22 has an internal space in which the electrochemical cell 10 is housed. Furthermore, at least a portion of the outer casing 22 has a function or structure that allows oxygen to pass through. Therefore, the oxygen generated at the oxygen generation electrode (positive electrode layer) 12 can be released to the outside by passing through the outer casing 22. In addition, as mentioned above, since the electrochemical cell 10 is an all-solid-state electrochemical cell that does not contain an electrolyte, the oxygen supply device 20 also has the advantage of not leaking.

[0029] The form of the outer casing 22 is not particularly limited, as long as at least a part of it has a function or structure that allows oxygen to permeate. For example, oxygen release holes 24 may be provided in the outer casing 22 as shown in Figures 2 and 4, or at least a part of the outer casing 22 may be made of an oxygen-permeable material. When oxygen release holes 24 are provided in the outer casing 22, it is preferable that the oxygen release holes 24 be provided in the part facing the positive electrode layer 12 as shown in Figure 2, but it is not limited to this, and may be in any position as long as the oxygen generated in the positive electrode layer 12 can be released to the outside of the outer casing 22.

[0030] The outer casing 22 can be appropriately selected according to the type of oxygen supply device 20. The outer casing 22 and the oxygen supply device 20 may be in the form of a coin-type battery as shown in Figures 2 and 4, or in the form of a pouch-type battery. For example, if the oxygen supply device 20 is in the form of a coin-type device as shown in Figures 2 and 4, the outer casing 22 preferably comprises a positive electrode can 22a, a negative electrode can 22b, and a gasket 22c, with the positive electrode can 22a and negative electrode can 22b being crimped together via the gasket 22c to form an internal space. The positive electrode can 22a and negative electrode can 22b may be made of metal such as stainless steel, and are not particularly limited. The gasket 22c may be an annular member made of insulating resin such as polypropylene, polytetrafluoroethylene, or PFA resin, and is not particularly limited.

[0031] If necessary, a positive electrode current collector layer 26 may be provided between the outer casing 22 and the positive electrode layer 12. A negative electrode current collector layer 28 may also be provided between the outer casing 22 and the negative electrode layer 14. However, the outer casing 22 itself can also function as a current collector. For example, the positive electrode can 22a may function as the positive electrode current collector layer 26, or the negative electrode can 22b may function as the negative electrode current collector layer 28.

[0032] The present invention will be further described in detail by the following examples. However, the present invention is not limited to the following examples. In the following examples, the mixing ratio of each component of the oxygen-generating electrode (positive electrode layer) is shown as a volume ratio. This volume ratio corresponds to the volume parts of each component when the total amount of metal oxide and lithium-ion conductive solid electrolyte described above is set to 100 volume parts.

[0033] Example 1 (1) Preparation of solid electrolyte powder Commercially available LiF (lithium fluoride) powder and commercially available AlF ３ (Aluminum fluoride) powder is LiF:AlF ３ The ingredients were weighed and mixed in a 3:1 (molar ratio). The resulting mixture was heated at 900°C and then ground in a mortar to obtain Li ３ AlF ６ A powder (i.e., LAF powder) was obtained. The obtained LAF powder and commercially available Li ２ SiF ６ The powder (i.e., LSF powder) and LAF were weighed together so that the LAF:LSF ratio was 80:20 (molar ratio), and a solid electrolyte powder containing LAF and LSF (hereinafter referred to as LAF-LSF powder) was obtained as a lithium-ion conductive solid electrolyte by mechanical milling using a planetary ball mill.

[0034] (2) Preparation of cathode powder for oxygen generation electrode (cathode layer) Li in an argon atmosphere having a dew point of -60°C or lower ２ O powder (corresponding to metal oxide 12a) and RuO ２ Powder (corresponding to oxygen evolution catalyst 12b) is Li ２ O: RuO ２The powders were weighed to achieve a volume ratio of 4:1. After mixing these powders in a dry mortar, a mechanical milling process (hereinafter referred to as Condition A) was performed at 300 rpm for 2 hours using a planetary ball mill (Fritsch P-6 Classic Line) to obtain RuO ２ Particles are Li ２ RuO supported on an O particle ２ Carry Li ２ O powder was obtained. RuO ２ Carry Li ２ O powder, carbon nanofiber (CNF) (corresponding to an electron conduction aid), and the LAF-LSF powder prepared in (1) above are mixed with RuO ２ Carry Li ２ O:CNF:LAF-LSF = 50:10:60 volume ratio (i.e., RuO ２ : Li ２ The following ingredients were weighed out so that O:CNF:LAF-LSF = 40:10:10:60, and these were mixed in a dry mortar to obtain the cathode powder.

[0035] (3) Preparation of the negative electrode layer An In metal foil with a thickness of 0.2 mm and a diameter of 16.5 mm was prepared as the negative electrode layer.

[0036] (4) Fabrication of the Oxygen Supply Device A coin-shaped oxygen supply device 20, schematically shown in Figure 2, was fabricated as follows. 165 mg of the LAF-LSF powder fabricated in (1) above was placed in a mold consisting of a resin sleeve with an inner diameter of 16.5 mm and upper and lower punches made of stainless steel, and a solid electrolyte layer 16 was obtained by uniaxial press molding at a pressure of 150 MPa. Subsequently, 136 mg of positive electrode preparation powder was placed on the solid electrolyte layer 16, and a pellet in which the oxygen generation electrode (positive electrode layer) 12 and the solid electrolyte layer 16 were laminated was fabricated by uniaxial press molding at a pressure of 150 MPa. After press molding of the obtained pellet by heating it at a temperature of 150°C and a pressure of 150 MPa for 12 hours, an In metal foil was bonded to the surface of the solid electrolyte layer 16 opposite to the positive electrode layer 12, and uniaxial press molding was performed at a pressure of 25 MPa. Thus, a pellet with a three-layer structure consisting of a positive electrode layer 12, a solid electrolyte layer 16, and a negative electrode layer 14 was fabricated. The obtained pellet was placed between a positive electrode can 22a and a negative electrode can 22b, which form a CR2032 type coin cell case equipped with oxygen supply holes, and sealed by crimping the positive electrode can 22a and negative electrode can 22b via a gasket 22c. The positive electrode can 22a has seven oxygen release holes 24 formed therein, and is configured to allow oxygen generated at the oxygen generation electrode (positive electrode layer) 12 to be released to the outside through the oxygen release holes 24. In this way, an oxygen supply device 20 including an all-solid-state electrochemical cell 10 was fabricated. Since this oxygen supply device 20 does not contain liquid, there is no risk of leakage.

[0037] (5) Measurement of oxygen generation The coin-shaped oxygen supply device 20 prepared in (4) above was sealed in a pouch equipped with a tab lead, and the oxygen supply device 20 was operated by applying a constant voltage of 4.38 V for 600 hours. The volume increase (ml) inside the pouch during operation was measured by the Archimedes method, and the measured volume increase was determined to be the amount of oxygen generated by the oxygen supply device 20. The measured amounts of oxygen generated are shown in Table 1.

[0038] Example 2 An oxygen supply device 20 was fabricated in the same manner as in Example 1, except that VGCF (registered trademark) (Vapor Grown Carbon Fiber) was used as an electron conduction aid in (2) above, and the amount of oxygen generated was measured.

[0039] Furthermore, the oxygen generation electrode 12 fabricated in this example (i.e., the RuO obtained by the catalyst loading treatment under condition A) ２ Carry Li ２ X-ray diffraction (XRD) was performed on the surface of the material (made using O powder) to obtain an X-ray diffraction profile. This XRD was performed using an XRD instrument (Bruker AXS, product name: D2 PHASER) under the following conditions: X-ray used: Cu-Kα rays, voltage: 30 kV, current: 10 mA, 2θ = 10 to 70°, step size: 0.02°. The obtained X-ray diffraction profile is shown in Figure 5. From Figure 5, it can be seen that in this oxygen generation electrode 12, Li ２ RuO ３ It was not possible to identify complex metal oxides like RuO ２ and Li ２ We were able to identify O.

[0040] Example 3 In (2) above, the proportion of each component is Li ２ O: RuO ２ An oxygen supply device 20 was fabricated in the same manner as in Example 1, except that the volume ratio of CNF:LAF-LSF was set to 40:15:10:60, and the amount of oxygen generated was measured.

[0041] Example 4 In (2) above, 1) VGCF was used as an electron conduction aid, and 2) the mixing ratio of various components was Li ２ O: RuO ２ An oxygen supply device 20 was fabricated in the same manner as in Example 1, except that the volume ratio of VGCF:LAF-LSF was set to 40:15:10:60, and the amount of oxygen generated was measured.

[0042] Example 5 (Comparison) In (2) above, mechanical milling by planetary ball mill was not performed (i.e., RuO ２ powder and Li ２ O powder to RuO ２ Carry Li２ An oxygen supply device 20 was fabricated in the same manner as in Example 4, except that the O powder was used as is without modification, and the amount of oxygen generated was measured.

[0043] Example 6 (Reference) In (2) above, Co is used as the oxygen evolution catalyst 12b ３ O ４ An oxygen supply device 20 was fabricated in the same manner as in Example 5, except that powder was used, and the amount of oxygen generated was measured. As shown in Table 1, in this example, the amount of oxygen generated was small because the oxygen generation catalyst 12b was not supported on the metal oxide 12a. Nevertheless, a certain amount of oxygen was observed, so Co was used as the oxygen generation catalyst 12b. ３ O ４ Even when using this method, it is believed that more oxygen can be generated by supporting the oxygen-evolving catalyst 12b on the metal oxide 12a.

[0044] Example 7 (Reference) An oxygen supply device 20 was fabricated in the same manner as in Example 5, except that LNFCu powder was used as the oxygen generation catalyst 12b in (2) above, and the amount of oxygen generated was measured. The LNFCu used in this example was LaNi ０．６５ Cu ０．３ Fe ０．０５ O ３ This is a perovskite-type oxide having the composition represented by [formula], and was prepared as follows.

[0045] (Preparation of oxygen-evolving catalyst (LNFCu)) First, lanthanum hydroxide powder, nickel oxide powder, copper oxide powder, and iron oxide powder were dried at 110°C for 12 hours. The dried powders were then processed into LaNi １－ｘ－ｙ Cu ｘ Fe ｙ O ３－δThe powders were weighed in a molar ratio where x = 0.3 and y = 0.05 in the general formula. These powders were wet-mixed in an aqueous medium and then dried. A mixed powder was then prepared by passing it through a sieve. Next, the mixed powder was placed in an alumina crucible with a lid and subjected to a solid-phase reaction by heat treatment in an oxygen atmosphere at a calcination temperature of 1100°C for 12 hours to obtain calcined powder of the perovskite phase. Analysis of the calcined powder by XRD confirmed that it was a single perovskite phase. The calcined powder was pulverized and subjected to uniaxial pressing, and then molded by CIP (Cold Isostatic Press). The obtained molded body was left to stand in an alumina sheath with a lid, and then heat-treated in an oxygen atmosphere at a calcination temperature of 1100°C for 12 hours to obtain a sintered body. The obtained sintered body was wet-pulverized in a pot mill to obtain LNFCu powder.

[0046] As shown in Table 1, in this example, the amount of oxygen generated was small because the oxygen-evolving catalyst 12b was not supported on the metal oxide 12a. However, since a certain amount of oxygen was observed, it is thought that even when LNFCu is used as the oxygen-evolving catalyst 12b, more oxygen can be generated by supporting the oxygen-evolving catalyst 12b on the metal oxide 12a.

[0047] Example 8 (Reference) In (2) above, MnO is used as the oxygen evolution catalyst 12b. ２ An oxygen supply device 20 was fabricated in the same manner as in Example 5, except that powder was used, and the amount of oxygen generated was measured. As shown in Table 1, in this example, the amount of oxygen generated was small because the oxygen generation catalyst 12b was not supported on the metal oxide 12a. Nevertheless, a certain amount of oxygen was observed, so MnO was used as the oxygen generation catalyst 12b. ２ Even when using this method, it is believed that more oxygen can be generated by supporting the oxygen-evolving catalyst 12b on the metal oxide 12a.

[0048] Example 9 (Comparison) In (2) above, the proportion of each component is Li ２ O: RuO ２An oxygen supply device 20 was fabricated in the same manner as in Example 5, except that the volume ratio of VGCF:LAF-LSF was set to 30:15:10:70, and the amount of oxygen generated was measured.

[0049] Example 10 (Comparison) In (2) above, the proportion of each component is Li ２ O: RuO ２ An oxygen supply device 20 was fabricated in the same manner as in Example 5, except that the volume ratio of VGCF:LAF-LSF was set to 20:15:10:80, and the amount of oxygen generated was measured.

[0050] Example 11 (Comparison) In (2) above, the proportion of each component is Li ２ O: RuO ２ An oxygen supply device 20 was fabricated in the same manner as in Example 5, except that the volume ratio of VGCF:LAF-LSF was set to 40:15:12.5:60, and the amount of oxygen generated was measured.

[0051] Example 12 (Comparison) In (2) above, 1) no electron conduction aid was used, and 2) the mixing ratio of various components was Li ２ O: RuO ２ An oxygen supply device 20 was fabricated in the same manner as in Example 5, except that the volume ratio of LAF-LSF was set to 40:30:60, and the amount of oxygen generated was measured.

[0052] Example 13 In (2) above, the proportion of each component is Li ２ O: RuO ２ An oxygen supply device 20 was fabricated in the same manner as in Example 1, except that the volume ratio of CNF:LAF-LSF was set to 40:5:10:60, and the amount of oxygen generated was measured.

[0053] Example 14 In (2) above, the proportion of each component is Li ２ O: RuO ２ An oxygen supply device 20 was fabricated in the same manner as in Example 2, except that the volume ratio of VGCF:LAF-LSF was set to 40:5:10:60, and the amount of oxygen generated was measured.

[0054] Example 15 In (1) above, LAF powder and commercially available Li ３ BO ３ Powder and LAF:Li ３BO ３ The materials are weighed so that the ratio is 90:10 (molar ratio), and then mechanically milled using a planetary ball mill to obtain LAF and Li ３ BO ３ An oxygen supply device 20 was fabricated in the same manner as in Example 2, except that a solid electrolyte powder containing the specified material was obtained as a lithium-ion conductive solid electrolyte, and the amount of oxygen generated was measured.

[0055] Example 16 In (1) above, LAF powder and commercially available Na ２ SiF ６ Powder and LAF:Na ２ SiF ６ The mixture is weighed to a molar ratio of 80:20 and mechanically milled using a planetary ball mill to obtain LAF and Na ２ SiF ６ An oxygen supply device 20 was fabricated in the same manner as in Example 2, except that a solid electrolyte powder containing the specified material was obtained as a lithium-ion conductive solid electrolyte, and the amount of oxygen generated was measured.

[0056] Example 17 In (2) above, Co is used as the oxygen evolution catalyst 12b ３ O ４ An oxygen supply device 20 was fabricated in the same manner as in Example 2, except that powder was used, and the amount of oxygen generated was measured.

[0057] Furthermore, similar to Example 2, X-ray diffraction (XRD) was performed on the surface of the oxygen generation electrode 12 to obtain an X-ray diffraction profile. The obtained X-ray diffraction profile is shown in Figure 6. From Figure 6, it was not possible to identify the composite metal oxide in this oxygen generation electrode 12, and Co ３ O ４ and Li ２ We were able to identify O.

[0058] Example 18 In (2) above, the proportion of each component is Li ２ O:Co ３ O ４ An oxygen supply device 20 was fabricated in the same manner as in Example 17, except that the volume ratio of VGCF:LAF-LSF was set to 40:15:10:60, and the amount of oxygen generated was measured.

[0059] Example 19 An oxygen supply device 20 was fabricated in the same manner as in Example 2, except that the LNFCu powder shown in Example 7 was used as the oxygen generation catalyst 12b in (2) above, and the amount of oxygen generated was measured.

[0060] Furthermore, similar to Example 2, X-ray diffraction (XRD) was performed on the surface of the oxygen generation electrode 12 to obtain an X-ray diffraction profile. The obtained X-ray diffraction profile is shown in Figure 7. From Figure 7, it was not possible to identify the composite metal oxide in this oxygen generation electrode 12, and LNFCu and Li were not identified. ２ We were able to identify O.

[0061] Example 20 In (2) above, the proportion of each component is Li ２ An oxygen supply device 20 was fabricated in the same manner as in Example 19, except that the volume ratio was set to O:LNFCu:VGCF:LAF-LSF = 40:15:10:60, and the amount of oxygen generated was measured.

[0062] Example 21 In (2) above, MnO is used as the oxygen evolution catalyst 12b. ２ Using powder, the proportion of each ingredient is Li ２ O: MnO ２ An oxygen supply device 20 was fabricated in the same manner as in Example 2, except that the volume ratio of VGCF:LAF-LSF was set to 70:17.5:10:30, and the amount of oxygen generated was measured.

[0063] Example 22 In (2) above, the proportion of each component is Li ２ O: MnO ２ An oxygen supply device 20 was fabricated in the same manner as in Example 21, except that the volume ratio of VGCF:LAF-LSF was set to 60:15:10:40, and the amount of oxygen generated was measured.

[0064] Example 23 In (2) above, the proportion of each component is Li ２ O: MnO ２ An oxygen supply device 20 was fabricated in the same manner as in Example 21, except that the volume ratio of VGCF:LAF-LSF was set to 40:10:10:60, and the amount of oxygen generated was measured.

[0065] Furthermore, similar to Example 2, X-ray diffraction (XRD) was performed on the surface of the oxygen-evolving electrode 12 to obtain an X-ray diffraction profile. The obtained X-ray diffraction profile is shown in Figure 8. From Figure 8, it was not possible to identify the composite metal oxide, and MnO ２ It could not be identified either. That is, Li ２ O with MnO ２ When supported, Mn-derived peaks could not be observed, and MnO ２ It was unclear what form it existed in.

[0066] This is the MnO used ２ This is thought to be due to the inherently weak peak intensity. Therefore, for verification, the following three types of powder were prepared: i) Li ２ O: MnO ２ = 1:1 (molar ratio) mixed powder:Li ２ MnO in O powder ２ Add an excess of powder, Li ２ O: MnO ２ Li such that the molar ratio is 1:1 ２ O and MnO ２ A mixed powder was prepared. ii) Supported powder under condition A: The mixed powder from i) above was subjected to mechanical milling (condition A) at 300 rpm for 2 hours using a planetary ball mill (Fritsch, P-6 Classic Line), thereby Li ２ O: MnO ２ = A supported powder was prepared by mixing in a 1:1 (molar ratio). iii) Supported powder under condition B: The mixed powder from i) above was subjected to mechanical milling at 200 rpm for 6 hours using a planetary ball mill (Fritsch, P-5 Classic Line) (condition B), thereby Li ２ O: MnO ２ A supported powder was prepared by mixing the components in a 1:1 (molar ratio).

[0067] X-ray diffraction (XRD) was performed on these three types of powders under the same conditions as in Example 2 to obtain X-ray diffraction profiles. The obtained X-ray diffraction profiles are shown in Figure 9. From Figure 9, it can be seen that when the powder was supported under condition A, Li ２ O and MnO２ Since a peak was observed, under condition A, Li ２ O and MnO ２ It could be inferred that the elements exist without reacting with each other (without forming a composite metal oxide). Therefore, the crystalline phase of the catalyst in this example 23 is MnO ２ This could be inferred. On the other hand, if the loading process is performed under condition B, Li ２ MnO ３ Since only the peak was observed, under condition B, Li ２ O and MnO ２ They react with each other to form a compound (complex metal oxide) of Li ２ MnO ３ It was inferred that a compound (particularly a composite metal oxide) was formed. From the above, it was found that when the oxygen-evolving catalyst 12b is supported on the metal oxide 12a, the oxygen-evolving catalyst 12b may form a compound (especially a composite metal oxide) with the metal oxide 12a depending on the conditions of the support treatment (for example, condition B).

[0068] Example 24 In (2) above, the proportion of each component is Li ２ O: MnO ２ An oxygen supply device 20 was fabricated in the same manner as in Example 21, except that the volume ratio of VGCF:LAF-LSF was set to 30:7.5:10:70, and the amount of oxygen generated was measured.

[0069] Example 25 In (2) above, the proportion of each component is Li ２ O: MnO ２ An oxygen supply device 20 was fabricated in the same manner as in Example 21, except that the volume ratio of VGCF:LAF-LSF was set to 20:5:10:80, and the amount of oxygen generated was measured.

[0070] Example 26 In (2) above, the proportion of each component is Li ２ O: MnO ２ An oxygen supply device 20 was fabricated in the same manner as in Example 21, except that the volume ratio of VGCF:LAF-LSF was set to 40:10:5:60, and the amount of oxygen generated was measured.

[0071] Example 27 In the same manner as in Example 23, an oxygen supply device 20 was fabricated and the amount of oxygen generated was measured, except that the loading process was performed by mechanical milling at 200 rpm for 6 hours using a planetary ball mill (Fritsch, P-5 Classic Line) as described in (2) above, under condition B.

[0072] Furthermore, similar to Example 23, X-ray diffraction (XRD) was performed on the surface of the oxygen-evolving electrode 12 to obtain an X-ray diffraction profile. The obtained X-ray diffraction profile is shown in Figure 8. From Figure 8, Li as a composite metal oxide... ２ MnO ３ We were able to identify it. This result is consistent with the above-mentioned hypothesis regarding condition B, shown in Figure 9.

[0073]

[0074]

[0075] 10: Electrochemical cell, 12: Oxygen-generating electrode, positive electrode layer, 12a: Metal oxide, 12b: Oxygen-generating catalyst, 14: Negative electrode layer, 16: Solid electrolyte layer, 20: Oxygen supply device, 22: Outer casing, 22a: Positive electrode canister, 22b: Negative electrode canister, 22c: Gasket, 24: Oxygen release vent

Claims

An oxygen generating electrode used in an oxygen supply device, The oxygen-evolving electrode comprises a metal oxide, a metal ion-conducting solid electrolyte, an oxygen-evolving catalyst, and an electron conduction aid. An oxygen-evolving electrode in which the oxygen-evolving catalyst is supported on the metal oxide. 　 The oxygen-generating electrode according to claim 1, wherein the metal oxide is a lithium oxide, and the metal ion-conducting solid electrolyte is a lithium ion-conducting solid electrolyte. 　 The lithium oxide is Li ２ O ２ and / or Li ２ The oxygen generating electrode according to claim 2, wherein the oxygen is O. 　 The oxygen evolution catalyst is RuO ２ MnO ２ Co ３ O ４ The oxygen-evolving electrode according to any one of claims 1 to 3, comprising at least one selected from the group consisting of, and perovskite-type oxides. 　 The perovskite-type oxide is LaNi １－ｘ－ｙ Cu ｘ Fe ｙ O ３－δ (where x > 0, y > 0, x + y < 1, 0 ≤ δ ≤ 0.4), the oxygen generation electrode according to claim 4, having a composition represented by the formula. 　 The oxygen generating electrode according to any one of claims 1 to 3, wherein the electron conduction aid is conductive carbon. 　 The oxygen-evolving electrode according to any one of claims 1 to 3, wherein at least a portion of the oxygen-evolving catalyst exists in the form of a compound of the oxygen-evolving catalyst and the metal oxide. 　 The metal oxide is Li ２ The oxygen is O, and the oxygen evolution catalyst is MnO ２ or RuO ２ The compound is Li ２ MnO ３ or Li ２ RuO ３ The oxygen generating electrode according to claim 7. 　 A positive electrode layer comprising an oxygen-generating electrode according to any one of claims 1 to 3, A negative electrode layer on which a metal derived from the metal oxide can be deposited, alloyed with the metal, or adsorbed, A solid electrolyte layer, composed of a metal ion conductive solid electrolyte, is interposed between the positive electrode layer and the negative electrode layer. An electrochemical cell equipped with [a specific feature / equipment]. 　 The electrochemical cell according to claim 9, wherein the metal ion conductive solid electrolyte contained in the oxygen generation electrode and the metal ion conductive solid electrolyte constituting the solid electrolyte layer are made of the same material. 　 The electrochemical cell according to claim 9, wherein the negative electrode layer and the solid electrolyte layer are adjacent to each other in such a way that a space is formed between them that allows for the deposition of the metal. 　 The negative electrode layer is made of In, Al, Sn, C, Si, Ca, Sr, Ba, Rh, Ir, Pd, Pt, Au, Zn, Ga, Ge, Pb, Sb, Bi, Cu, stainless steel, SiO, TiO ２ Li ４ Ti ５ O １２ MnO ２ ,CuO,Fe ２ O ３ CuF ２ FeF ２ FeF ３ and AlF ３ The electrochemical cell according to claim 9, comprising at least one selected from the group consisting of the following. 　 The electrochemical cell according to claim 9, wherein the metal ion conductive solid electrolyte constituting the solid electrolyte layer contains fluoride. 　 The fluoride is Li ３ AlF ６ The electrochemical cell according to claim 13, including the following: 　 The fluoride is Li ３ AlF ６ and Li ２ SiF ６ The electrochemical cell according to claim 14, which is a mixture of the above. 　 The electrochemical cell according to claim 9, An outer casing having an internal space, in which the electrochemical cell is housed, wherein at least a portion of the outer casing has a function or structure that allows oxygen to permeate, An oxygen supply device equipped with [specific features / equipment]. 　 The oxygen supply device according to claim 16, further comprising a positive electrode current collector layer disposed between the outer casing and the positive electrode layer, and / or a negative electrode current collector layer disposed between the outer casing and the negative electrode layer.

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