JP2011253789A - Metal-air battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of metal carbonate on a positive electrode in discharge.SOLUTION: A metal-air battery 1 is a secondary battery comprising a positive electrode 2, a negative electrode 3, an electrolyte layer 4, and an air introduction pipe 5. The positive electrode 2 is a porous member which is bottomed and nearly cylindrical, and comprises a positive electrode support 21 made of alumina, a positive electrode conductive layer 22 made of perovskite oxide which has conductivity, and a positive electrode catalyst layer 23 made of manganese dioxide. The negative electrode 3 comprises a negative electrode support 31 made of stainless steel and a negative electrode conductive layer 32 made of lithium or lithium alloy. In the metal-air battery 1, the positive electrode 2 without carbon is realized by forming the positive electrode catalyst layer 23 on the positive electrode conductive layer 22 made of perovskite oxide. Therefore, generation of lithium carbonate on the positive electrode 2 in discharge is prevented, and low charging voltage of the metal-air battery 1 is realized.

Description

  The present invention relates to a metal-air battery.

  2. Description of the Related Art Conventionally, metal-air batteries using a metal as a negative electrode active material and oxygen in the air as a positive electrode active material are known. For example, Patent Document 1 proposes that in a metal-air battery in which an electrolyte-containing layer is provided between a positive electrode and a negative electrode, the electrolyte contains an ionic liquid, inorganic fine particles, and an electrolyte salt. In Patent Document 2, in a metal-air battery in which a positive electrode and a negative electrode are arranged in a non-aqueous electrolyte, an oxygen pump that supplies oxygen in the air to the positive electrode through an oxygen ion conductive solid electrolyte is provided. Proposed.

In the lithium air secondary battery of Patent Document 3, the positive electrode contains a positive electrode catalyst having an oxygen absorption / release capability, a carbon material, and an organic binder (carbon fiber or the like), and the negative electrode is formed of plate-like lithium. As the positive electrode catalyst, manganese dioxide (MnO ₂ ), perovskite oxide, or the like is used. In the lithium-air secondary battery of Patent Document 4, the positive electrode is a gas diffusion oxygen electrode mainly composed of carbon (C), and the negative electrode is formed of metal lithium or a material capable of occluding and releasing lithium ions. The positive electrode contains 20 to 60% by weight of an iron (Fe) -based oxide having a perovskite structure.

JP 2008-66202 A JP 2009-230981 A JP 2008-1112724 A JP 2009-283181 A

By the way, in the metal-air batteries of Patent Document 1 to Patent Document 4, since the positive electrode contains carbon as a conductive material, lithium carbonate (Li ₂ CO ₃ ), which is a carbonate of the negative electrode metal, is present on the positive electrode during discharge. Precipitate. In such a metal-air battery, since a large amount of energy is required to electrolyze and ionize lithium carbonate at the time of charging, the charging voltage becomes high.

  This invention is made | formed in view of the said subject, and makes it the main objective to prevent that a metal carbonate is produced | generated on a positive electrode in the case of discharge.

  The invention according to claim 1 is a metal-air battery, which contains a metal and generates a metal ion upon discharge, a conductive perovskite oxide, and a catalyst for promoting an oxygen reduction reaction And a porous positive electrode that does not contain carbon and generates oxygen ions during discharge, and a non-aqueous electrolyte layer disposed between the negative electrode and the positive electrode and in contact with the negative electrode.

  The invention according to claim 2 is the metal-air battery according to claim 1, wherein the positive electrode contains the lanthanum perovskite oxide.

  The invention described in claim 3 is the metal-air battery according to claim 1 or 2, wherein the metal contained in the negative electrode is lithium.

  A fourth aspect of the present invention is the metal-air battery according to any one of the first to third aspects, wherein the positive electrode is formed of a support portion and the perovskite oxide on the support portion. A conductive film and a catalyst layer formed on the conductive film by the catalyst.

  The invention according to claim 5 is the metal-air battery according to any one of claims 1 to 4, further comprising another electrolyte layer disposed between the electrolyte layer and the positive electrode and in contact with the positive electrode. And a partition layer that is disposed between the electrolyte layer and the another electrolyte layer and is a solid electrolyte or a separator in contact with the electrolyte layer and the another electrolyte layer.

  The invention according to claim 6 is the metal-air battery according to claim 5, wherein the partition wall layer is a membrane-like solid electrolyte, and the electrolyte layer is impregnated with a non-aqueous electrolyte solution. It is a polymer and supports the partition layer.

  A seventh aspect of the present invention is the metal-air battery according to any one of the first to sixth aspects, wherein the negative electrode is disposed on the outer periphery and the positive electrode is disposed on the inner periphery.

  The invention according to claim 8 is the metal-air battery according to any one of claims 1 to 7, wherein the electrolyte layer is formed of an electrolyte solution, and the electrolyte solution contains inorganic fine particles.

  The invention according to claim 9 is the metal-air battery according to any one of claims 1 to 8, wherein the electrolyte layer is formed of an electrolyte solution, and the electrolyte layer circulates the electrolyte solution. Connected to.

  A tenth aspect of the present invention is the metal-air battery according to any one of the first to ninth aspects, further comprising a gas supply unit that supplies air from which moisture and carbon dioxide have been removed to the positive electrode.

  In this invention, it can prevent that a metal carbonate is produced | generated on a positive electrode in the case of discharge.

It is a longitudinal cross-sectional view of the metal air battery which concerns on 1st Embodiment. It is a cross-sectional view of a metal air battery. It is a longitudinal cross-sectional view of the metal air battery which concerns on 2nd Embodiment. It is a cross-sectional view of a metal air battery. It is a cross-sectional view of the metal air battery which concerns on 3rd Embodiment. It is a cross-sectional view of the metal air battery which concerns on 4th Embodiment. It is a longitudinal cross-sectional view of the metal air battery which concerns on 5th Embodiment.

  FIG. 1 is a longitudinal sectional view showing a metal-air battery 1 according to the first embodiment of the present invention. The metal-air battery 1 has a substantially cylindrical shape, and FIG. 1 shows a cross section including the central axis J1 of the metal-air battery 1. FIG. 2 is a cross-sectional view of the metal-air battery 1 cut at the position AA in FIG. As shown in FIGS. 1 and 2, the metal-air battery 1 is a secondary battery that includes a positive electrode 2, a negative electrode 3, an electrolyte layer 4, and an air introduction tube 5, and extends radially outward from the central axis J <b> 1. The air introduction tube 5, the positive electrode 2, the electrolyte layer 4 and the negative electrode 3 are arranged concentrically in this order. In other words, the metal-air battery 1 has a substantially cylindrical shape in which the negative electrode 3 is disposed on the outer periphery and the positive electrode 2 is disposed on the inner periphery.

  The positive electrode 2 is a substantially bottomed cylindrical porous member, and includes a substantially bottomed cylindrical positive electrode support 21, a positive electrode conductive layer 22, and a positive electrode catalyst layer 23. The positive electrode conductive layer 22 is stacked on the outer surface and the outer bottom surface of the positive electrode support portion 21, and the positive electrode catalyst layer 23 is stacked on the outer surface and the outer bottom surface of the positive electrode conductive layer 22. In the positive electrode 2, a positive electrode current collector 24 is provided on a part of the outer surface of the positive electrode conductive layer 22 instead of the positive electrode catalyst layer 23, and the positive electrode current collector 24 is disposed at the upper end of the positive electrode current collector 24 as shown in FIG. Terminal 25 is connected. The positive electrode 2 and the positive electrode current collector 24 do not contain carbon (C).

The positive electrode support portion 21 is a porous member formed of a metal such as alumina (aluminum oxide: Al ₂ O ₃ ), zirconia, ceramic, stainless steel, etc. In this embodiment, the positive electrode support portion 21 is an insulator. It is made of some alumina. The positive electrode support 21 is formed by extrusion molding, CIP (Cold Isostatic Press) and firing, or HIP (Hot Isostatic Press).

The positive electrode conductive layer 22 is a porous thin conductive film mainly formed of a conductive perovskite oxide (usually in powder form), and preferably has a chemical formula A _1-x BO ₃ (0.9 It is formed of a perovskite oxide represented by ≦ 1-x <1.0). In the present embodiment, the positive electrode conductive layer 22 includes a lanthanum perovskite oxide (specifically, lanthanum strontium manganite (LSM: La (Sr) MnO ₃ ) or lanthanum strontium cobaltite (LSC: La (Sr) A perovskite oxide containing lanthanum at the A site such as CoO ₃ ). The positive electrode conductive layer 22 is formed by a slurry coating method, a hydrothermal synthesis method, CVD (Chemical Vapor Deposition), PVD (Physical Vapor Deposition), or the like.

The positive electrode catalyst layer 23 is a porous member mainly formed of a metal oxide such as manganese (Mn), nickel (Ni), or cobalt (Co) that is a catalyst for promoting an oxygen reduction reaction. The positive electrode catalyst layer 23 is formed of a noble metal such as platinum (Pt), palladium (Pd), silver (Ag), rhodium (Rh), ruthenium (Ru), or a mixture of these noble metals and the above metal oxide. May be. In the present embodiment, the positive electrode catalyst layer 23 is formed of manganese dioxide (MnO ₂ ) having a β-type (rutile) crystal structure. The positive electrode catalyst layer 23 is formed by a slurry coating method and baking, a hydrothermal synthesis method, CVD, PVD, or the like.

  As shown in FIGS. 1 and 2, the negative electrode 3 includes a substantially bottomed cylindrical negative electrode support portion 31, and a substantially bottomed cylindrical negative electrode layered on the inner side surface and the inner bottom surface of the negative electrode support portion 31. A conductive layer 32 is provided. The negative electrode support 31 is a negative electrode current collector formed of a conductive material such as metal (stainless steel in the present embodiment). On the outer surface of the negative electrode support 31, as shown in FIG. A current collecting terminal 33 is provided. The negative electrode conductive layer 32 is a thin conductive film formed of a metal such as lithium (Li) or zinc (Zn), or an alloy containing the metal. In this embodiment, the negative electrode conductive layer 32 is lithium or lithium. It is formed from an alloy. The negative electrode conductive layer 32 is formed by, for example, a slurry coating method.

  The electrolyte layer 4 is formed of a non-aqueous electrolyte. In the present embodiment, the electrolyte layer 4 is formed by filling (disposing) an organic solvent-based electrolyte solution between the positive electrode 2 and the negative electrode 3. The electrolyte layer 4 is in contact with the positive electrode catalyst layer 23 of the positive electrode 2, the positive electrode current collector 24, and the negative electrode conductive layer 32 of the negative electrode 3. The upper surface of the electrolyte layer 4 is closed by a substantially annular inner lid 51 in contact with the outer surface of the positive electrode support portion 21 and the inner surface of the negative electrode support portion 31, and has the same shape as the inner lid 51 above the inner lid 51. An upper lid 52 is provided to close the upper opening of the substantially bottomed cylindrical negative electrode 3.

  The air introduction tube 5 is arranged inside the substantially bottomed cylindrical positive electrode 2, and the lower end of the air introduction tube 5 is located near the bottom of the positive electrode support portion 21 of the positive electrode 2. The upper end of the air introduction pipe 5 is connected to a removal unit 53 that removes moisture and carbon dioxide from the air. The removing unit 53 removes moisture and carbon dioxide in the air by membrane separation or adsorption. Air from the removing unit 53 (that is, air from which moisture and carbon dioxide have been removed) is guided to the vicinity of the bottom inside the positive electrode 2 by the air introduction tube 5 and is supplied to the positive electrode 2 while being supplied to the inner surface of the positive electrode 2. Are discharged from the upper opening of the positive electrode 2 to the outside. In the metal-air battery 1, the air introduction tube 5 serves as a gas supply unit that supplies the air from the removal unit 53 to the positive electrode 2. The air supplied to the positive electrode 2 passes through the positive electrode support portion 21 and the positive electrode conductive layer 22 which are porous members, and is supplied to the positive electrode catalyst layer 23.

When discharging is performed in the metal-air battery 1, the negative electrode current collecting terminal 33 and the positive electrode current collecting terminal 25 are electrically connected via a load (for example, a lighting fixture). In the negative electrode 3, lithium contained in the negative electrode conductive layer 32 is oxidized to generate lithium ions (Li ⁺ ), and electrons are supplied to the positive electrode 2 through the negative electrode current collector terminal 33, the positive electrode current collector 24, and the positive electrode current collector terminal 25. To be supplied. In the positive electrode 2, oxygen in the air supplied from the air introduction tube 5 is reduced by electrons supplied from the negative electrode 3 to generate oxygen ions (O ²⁻ ). In the positive electrode 2, the generation of oxygen ions (that is, the oxygen reduction reaction) is promoted by the positive electrode catalyst contained in the positive electrode catalyst layer 23, so the overvoltage due to the energy consumed in the reduction reaction is reduced, and the metal-air battery 1. The discharge voltage can be increased. Oxygen ions generated at the positive electrode 2 are combined with lithium ions dissolved in the electrolyte layer 4 from the negative electrode 3, thereby generating lithium oxide (Li ₂ O).

  On the other hand, when charging is performed in the metal-air battery 1, a voltage is applied between the negative electrode current collector terminal 33 and the positive electrode current collector terminal 25, lithium oxide is decomposed at the positive electrode 2, and positive electrode current is collected from oxygen ions. Electrons are supplied to the positive electrode current collector terminal 25 through the electric body 24 to generate oxygen. In the negative electrode 3, lithium ions are reduced by electrons supplied to the negative electrode current collector terminal 33, and lithium is deposited on the surface of the negative electrode conductive layer 32. In the positive electrode 2, since the generation of oxygen is promoted by the positive electrode catalyst contained in the positive electrode catalyst layer 23, the overvoltage is reduced and the charging voltage of the metal-air battery 1 can be lowered.

By the way, a positive electrode of a normal metal-air battery is mainly composed of carbon for obtaining conductivity, and a positive electrode catalyst for promoting a reduction reaction of oxygen is added to the carbon. However, in such a metal-air battery, lithium ions generated during discharge are deposited on the positive electrode as lithium carbonate (Li ₂ CO ₃ ), and the lithium carbonate is electrolyzed and ionized during charging. Since a large amount of energy is required, the charging voltage becomes high.

In contrast, in the metal-air battery 1 according to the present embodiment, the positive electrode 2 containing no carbon is realized by forming the positive electrode catalyst layer 23 on the positive electrode conductive layer 22 formed of a perovskite oxide. be able to. Thereby, it can prevent that lithium carbonate is produced | generated on the positive electrode 2 in the case of discharge, and the charge voltage of the metal air battery 1 can be made low. Further, since the positive electrode conductive layer 22 contains a highly conductive lanthanum perovskite oxide, the discharge voltage of the metal-air battery 1 can be increased. Further, the perovskite oxide contained in the positive electrode conductive layer 22 is represented by the chemical formula A _1-x BO ₃ (0.9 ≦ 1-x <1.0), whereby the positive electrode conductive layer 22 It is possible to prevent deterioration due to moisture and improve the durability of the metal-air battery 1.

  In the metal-air battery 1, since the positive electrode conductive layer 22 of the positive electrode 2 is a thin conductive film supported (supported) by the positive electrode support portion 21, it is possible to reduce the amount of relatively expensive perovskite oxide used. . As a result, the manufacturing cost of the metal-air battery 1 can be reduced. Moreover, since the negative electrode 3 contains lithium or a lithium alloy having a high theoretical voltage and an electrochemical equivalent, the capacity of the metal-air battery 1 can be increased.

  As described above, since the metal-air battery 1 has a cylindrical shape in which the negative electrode 3 and the positive electrode 2 are disposed on the outer periphery and the inner periphery, respectively, A thin film layer such as the conductive layer 32 and the positive electrode conductive layer 22 can be easily formed. That is, it is possible to easily cope with an increase in size of the metal-air battery 1. In addition, when air from which moisture and carbon dioxide have been removed is supplied to the positive electrode 2 through the air introduction tube 5, carbon dioxide in the air reacts with lithium ions, and lithium carbonate adheres to the positive electrode 2. In addition to being prevented, lithium contained in the negative electrode conductive layer 32 of the negative electrode 3 is prevented from reacting with moisture and deteriorating the negative electrode conductive layer 32.

In the metal-air battery 1, inorganic fine particles (filler) may be added to the non-aqueous electrolyte solution of the electrolyte layer 4. As the inorganic fine particles, inorganic oxides such as alumina, silicon dioxide (SiO ₂ ), titanium dioxide (TiO ₂ ), zeolite, and perovskite oxide are preferable, and the Si ratio is particularly high (for example, Si / Al is 2 or more). Zeolite particles are preferred. When the electrolyte solution of the electrolyte layer 4 contains inorganic fine particles, the internal resistance of the metal-air battery 1 is reduced and the battery capacity is increased, and leakage from the metal-air battery 1 is prevented. Even in the metal-air battery according to the following embodiment, the non-aqueous electrolyte solution contained in the first electrolyte layer 4 described later contains inorganic fine particles, so that the same effect as described above (that is, an increase in battery capacity) And prevention of leakage).

  Next, a metal air battery according to a second embodiment of the present invention will be described. 3 and 4 are a longitudinal sectional view and a transverse sectional view of the metal-air battery 1a according to the second embodiment, and FIG. 4 shows the metal-air battery 1a at the position BB in FIG. It is the figure which cut | disconnected. 3 and 4, the illustration of the removal unit 53 is omitted to simplify the drawing (the same applies to FIGS. 5 to 7).

  In the metal-air battery 1 a, another electrolyte layer 6 is disposed between the electrolyte layer 4 and the positive electrode 2, and a partition wall layer 7 is disposed between the electrolyte layer 4 and the electrolyte layer 6. The partition layer 7 is a thin-film solid electrolyte, and selectively allows only lithium ions to pass therethrough. Other configurations are the same as those of the metal-air battery 1 shown in FIGS. 1 and 2, and in the following description, the same reference numerals are given to the corresponding configurations. Further, in order to distinguish between the two electrolyte layers 4 and 6, the electrolyte layer 4 and the electrolyte layer 6 are referred to as “first electrolyte layer 4” and “second electrolyte layer 6”, respectively.

As shown in FIGS. 3 and 4, the second electrolyte layer 6 has a substantially bottomed cylindrical shape centered on the central axis J <b> 1 and is in contact with the positive electrode 2. The partition wall layer 7 also has a substantially bottomed cylindrical shape and is in contact with the first electrolyte layer 4 and the second electrolyte layer 6. The second electrolyte layer 6 is formed by filling (arranging) an aqueous electrolyte solution between the positive electrode 2 and the partition wall layer 7. Similar to the top surface of the first electrolyte layer 4, the top surface of the second electrolyte layer 6 is closed by a substantially annular inner lid 51 (shown only in FIG. 3). In the present embodiment, the first electrolyte layer 4 is a porous polymer impregnated with a non-aqueous (eg, organic solvent-based) electrolyte solution, and the partition layer 7 that is a thin-film solid electrolyte is the first electrolyte layer. The first electrolyte layer 4 supports (supports) the inner surface and the inner bottom surface of the layer 4. That is, the first electrolyte layer 4 is also a partition support layer that supports the partition layer 7. Further, as the partition wall layer 7, glass ceramics (LTAP) represented by the chemical formula Li _{1 + x + y} Ti _2−x Al _x P _3−y Si _y O ₁₂ is used.

When discharging is performed in the metal-air battery 1a, lithium contained in the negative electrode conductive layer 32 of the negative electrode 3 is oxidized to generate lithium ions, and electrons are collected in the negative electrode current collector terminal 33, the positive electrode current collector 24, and the positive electrode current collector. It is supplied to the positive electrode 2 through the electric terminal 25. The negative electrode current collecting terminal 33 and the positive electrode current collecting terminal 25 are illustrated only in FIG. In the positive electrode 2, oxygen in the air supplied from the air introduction tube 5 is reduced by electrons supplied from the negative electrode 3 to generate oxygen ions, and the oxygen ions react with water contained in the second electrolyte layer 6. Thus, hydroxide ions (OH ⁻ ) are generated. The hydroxide ions become lithium hydroxide (LiOH) together with the lithium ions dissolved in the electrolyte layer 4 from the negative electrode 3. Since lithium hydroxide is water-soluble, it dissolves in the aqueous electrolyte solution of the second electrolyte layer 6.

  When charging is performed in the metal-air battery 1a, a voltage is applied between the negative electrode current collector terminal 33 and the positive electrode current collector terminal 25, and electrons are transferred from the hydroxide ions to the positive electrode current collector terminal 25 in the positive electrode 2. Supplying water and oxygen. In the negative electrode 3, lithium ions are reduced by electrons supplied to the negative electrode current collector terminal 33, and lithium is deposited on the surface of the negative electrode conductive layer 32.

  In the metal-air battery 1a, as in the first embodiment, since the positive electrode 2 does not contain carbon, it is possible to prevent lithium carbonate from being generated on the positive electrode 2 during discharge. The charging voltage of 1a can be lowered. In the metal-air battery 1a, in particular, by providing the partition layer 7 between the positive electrode 2 and the negative electrode 3, when lithium is deposited in a dendritic shape on the negative electrode 3 during charging, the portion (in a dendritic shape) ( The growth of so-called dendrites toward the positive electrode 2 can be suppressed. As a result, it is possible to prevent the dendrite from reaching the positive electrode 2 and causing a short circuit. Further, by supporting the partition wall layer 7 by the first electrolyte layer 4, the thin film partition wall layer 7 can be easily installed, and as a result, the metal-air battery 1a can be downsized. Furthermore, since the partition wall layer 7 is thin, the ionic conductivity is increased as compared with the case where the partition wall layer 7 is thickened.

  Next, a metal air battery according to a third embodiment of the present invention will be described. FIG. 5 is a cross-sectional view of a metal-air battery 1b according to the third embodiment. In the metal-air battery 1b, a partition wall layer 7a as a separator is provided instead of the partition layer 7 (solid electrolyte) of the metal-air battery 1a shown in FIGS. Other configurations are the same as those of the metal-air battery 1a shown in FIGS. 3 and 4, and in the following description, the corresponding components are denoted by the same reference numerals.

  The partition layer 7a is a porous member formed of ceramic, metal, inorganic material, organic material, or the like, and holds an electrolyte that selectively allows lithium ions to pass through in the pores. The partition wall layer 7a is formed by extrusion molding, CIP and baking, HIP, or the like. The reaction in discharging and charging in the metal-air battery 1b is the same as that in the metal-air battery 1a according to the second embodiment.

  In the metal-air battery 1b, as in the first and second embodiments, since the positive electrode 2 does not contain carbon, it is possible to prevent lithium carbonate from being generated on the positive electrode 2 during discharge, The charging voltage of the metal-air battery 1b can be lowered. Further, by providing the partition layer 7a between the positive electrode 2 and the negative electrode 3, as in the second embodiment, the growth of dendrites on the negative electrode 3 during charging is suppressed and a short circuit occurs. Can be prevented. In the metal-air battery 1b, in particular, the support by the first electrolyte layer 4 is not necessary for the installation of the partition wall layer 7a, which is a separator. Therefore, the degree of freedom in selecting the material of the first electrolyte layer 4 is improved.

  Next, a metal air battery according to a fourth embodiment of the present invention will be described. FIG. 6 is a cross-sectional view of a metal-air battery 1c according to the fourth embodiment. The metal-air battery 1c has the same configuration as that of the metal-air battery 1a shown in FIGS. 3 and 4 except that a partition support layer 71 is provided between the second electrolyte layer 6 and the partition layer 7, and includes the following: In the description, the same reference numerals are assigned to the corresponding components.

  The partition support layer 71 is a porous member formed by a method such as extrusion, CIP and firing, or HIP using ceramic, metal, inorganic material or organic material, and the second electrolyte layer 6 is formed in the hole. The aqueous electrolyte solution is impregnated. The partition wall layer 7, which is a thin-film solid electrolyte, is supported (supported) by the partition wall support layer 71 on the outer surface and the outer bottom surface of the partition wall support layer 71. Reactions in discharging and charging in the metal-air battery 1c are the same as those in the metal-air battery 1a according to the second embodiment.

  In the metal-air battery 1c, as in the first to third embodiments, since the positive electrode 2 does not contain carbon, it is possible to prevent lithium carbonate from being generated on the positive electrode 2 during discharge, The charging voltage of the metal-air battery 1c can be lowered. Further, by providing the partition wall layer 7 and the partition support layer 71 between the positive electrode 2 and the negative electrode 3, as in the second embodiment, the growth of dendrites on the negative electrode 3 during charging is suppressed and a short circuit occurs. Can be prevented. As described above, in the metal-air battery 1c, the partition layer 7 is supported by the partition support layer 71, and it is not necessary to support the partition layer 7 by the first electrolyte layer 4. Therefore, the material selection of the first electrolyte layer 4 is not necessary. The degree of freedom is improved.

  Next, a metal air battery according to a fifth embodiment of the present invention will be described. FIG. 7 is a longitudinal sectional view of a metal-air battery 1d according to the fifth embodiment. In the metal-air battery 1d, the first electrolyte layer 4 is connected to a circulation mechanism 81 that circulates the non-aqueous electrolyte solution of the first electrolyte layer 4, and the second electrolyte layer 6 is connected to the second electrolyte layer 6. The metal-air battery 1c shown in FIG. 6 has the same configuration except that it is connected to an exchange mechanism for exchanging the aqueous electrolyte solution. In the following description, the same reference numerals are given to the corresponding configurations.

  As shown in FIG. 7, a supply port 41 for supplying the electrolyte solution to the first electrolyte layer 4 and a discharge port 42 for discharging the electrolyte solution of the first electrolyte layer 4 are provided at the side of the metal-air battery 1d. It is formed. The supply port 41 and the discharge port 42 are connected to the circulation mechanism 81 through the conduit 43, and the electrolyte solution discharged from the discharge port 42 is supplied again from the supply port 41 to the first electrolyte layer 4 through the circulation mechanism 81. Is done. Thereby, the flow of the electrolyte solution is generated in the first electrolyte layer 4, and the generation and growth of dendrite during the charging of the metal-air battery 1d is suppressed. Further, the circulation mechanism 81 is provided with a filter, and the lithium is collected in the circulation mechanism 81 when a thin piece of lithium is peeled off from the negative electrode conductive layer 32 during charging or the like.

  In the metal-air battery 1d, a supply port 61 for supplying an electrolyte solution to the second electrolyte layer 6 and a discharge port 62 for discharging the electrolyte solution of the second electrolyte layer 6 are formed. The supply port 61 is connected to the supply mechanism 821 of the exchange mechanism, and a new electrolyte solution is supplied from the supply mechanism 821 to the second electrolyte layer 6. The discharge port 62 is connected to the recovery mechanism 822 of the exchange mechanism, and the electrolyte solution discharged from the second electrolyte layer 6 is recovered by the recovery mechanism 822. This prevents the electrolyte solution of the second electrolyte layer 6 from being saturated with lithium hydroxide during the discharge of the metal-air battery 1d, and can increase the discharge time of the metal-air battery 1d. Lithium is recovered from the electrolyte solution recovered by the recovery mechanism 822. The lithium may be reused as the negative electrode conductive layer 32 of the metal-air battery.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to the said embodiment, A various change is possible.

  In the negative electrode 3, the negative electrode support portion 31 is not necessarily formed of a conductive material. When the negative electrode support portion 31 is formed of an insulator, the negative electrode current collector terminal 33 penetrates the negative electrode support portion 31. Thus, the negative electrode conductive layer 32 is electrically connected. The negative electrode support 31 is not necessarily provided, and the entire negative electrode 3 may be formed of lithium or a lithium alloy. The negative electrode conductive layer 32 may be formed of various materials including a metal that is oxidized during discharge to generate metal ions.

  In the positive electrode 2, when the positive electrode support portion 21 is formed of a conductive material, the positive electrode current collector 24 may be omitted and the positive electrode current collector terminal 25 may be provided on the inner surface of the positive electrode support portion 21. When the positive electrode conductive layer 22 has a certain thickness, the positive electrode support portion 21 that supports the positive electrode conductive layer 22 may be omitted. In this case, the positive electrode current collecting terminal 25 is provided on the inner surface of the positive electrode conductive layer 22.

  In the metal-air battery, a conductive layer is formed from a mixture of the material of the positive electrode support portion 21 and the material of the positive electrode conductive layer 22 (that is, a perovskite oxide), and the positive electrode catalyst layer 23 is formed on the conductive layer. And may be the positive electrode 2. Alternatively, the positive electrode 2 may be formed from a mixture of the positive electrode support portion 21, the positive electrode conductive layer 22, and the positive electrode catalyst layer 23. In any case, since the positive electrode 2 contains a conductive perovskite oxide and a catalyst that promotes an oxygen reduction reaction and does not contain carbon, the negative electrode is discharged during discharge of a metal-air battery. 3 is prevented from being produced on the positive electrode 2.

  In the metal-air battery 1 according to the first embodiment, the electrolyte layer 4 may be formed of a nonaqueous electrolyte, for example, a solid electrolyte. When the electrolyte layer 4 is formed of a solid electrolyte, the generation and growth of dendrites are suppressed. In the metal-air battery according to the second to fourth embodiments, the second electrolyte layer 6 may be formed of a non-aqueous electrolyte (for example, a non-aqueous electrolyte solution or a solid electrolyte). When the second electrolyte layer 6 is formed of a non-aqueous electrolyte solution, the above-described inorganic fine particles (filler) may be added to the electrolyte solution, and the electrolyte solution contains inorganic fine particles, so that the inside of the metal-air battery The resistance is reduced and the battery capacity is increased, and leakage from the metal-air battery is prevented.

  The structure of the metal-air battery described above may be applied to a metal-air battery having a shape other than a cylindrical shape (for example, a flat plate shape). Moreover, in the said embodiment, although the secondary battery was demonstrated, the structure of the above-mentioned metal air battery may be applied to a primary battery or a fuel cell.

DESCRIPTION OF SYMBOLS 1,1a-1d Metal-air battery 2 Positive electrode 3 Negative electrode 4 (1st) Electrolyte layer 5 Air introduction pipe 6 2nd electrolyte layer 7, 7a Partition layer 21 Positive electrode support part 22 Positive electrode conductive layer 23 Positive electrode catalyst layer 81 Circulation mechanism

Claims (10)

A metal-air battery,
A negative electrode containing metal and generating metal ions during discharge;
A perovskite oxide having conductivity, and a porous positive electrode that contains a catalyst that promotes an oxygen reduction reaction and does not contain carbon, and generates oxygen ions during discharge;
A non-aqueous electrolyte layer disposed between the negative electrode and the positive electrode and in contact with the negative electrode;
A metal-air battery comprising: The metal-air battery according to claim 1,
The metal-air battery, wherein the positive electrode contains the lanthanum-based perovskite oxide. The metal-air battery according to claim 1 or 2,
The metal-air battery, wherein the metal contained in the negative electrode is lithium. The metal-air battery according to any one of claims 1 to 3,
The positive electrode is
A support part;
A conductive film formed of the perovskite oxide on the support;
A catalyst layer formed by the catalyst on the conductive film;
A metal-air battery comprising: The metal-air battery according to any one of claims 1 to 4,
Another electrolyte layer disposed between the electrolyte layer and the positive electrode and in contact with the positive electrode;
A partition layer disposed between the electrolyte layer and the another electrolyte layer and being a solid electrolyte or separator in contact with the electrolyte layer and the other electrolyte layer;
A metal-air battery, further comprising: The metal-air battery according to claim 5,
The partition layer is a membrane-shaped solid electrolyte,
The metal-air battery, wherein the electrolyte layer is a porous polymer impregnated with a non-aqueous electrolyte solution and supports the partition wall layer. The metal-air battery according to any one of claims 1 to 6,
A metal-air battery, characterized in that the negative electrode is disposed on the outer periphery and the positive electrode is disposed on the inner periphery. The metal-air battery according to any one of claims 1 to 7,
The metal-air battery, wherein the electrolyte layer is formed of an electrolyte solution, and the electrolyte solution contains inorganic fine particles. The metal-air battery according to any one of claims 1 to 8,
The metal-air battery, wherein the electrolyte layer is formed of an electrolyte solution, and the electrolyte layer is connected to a mechanism for circulating the electrolyte solution. The metal-air battery according to any one of claims 1 to 9,
A metal-air battery, further comprising a gas supply unit that supplies air from which moisture and carbon dioxide have been removed to the positive electrode.

Images