WO2016080115A1 - Metal-air battery - Google Patents

Metal-air battery Download PDF

Info

Publication number
WO2016080115A1
WO2016080115A1 PCT/JP2015/079134 JP2015079134W WO2016080115A1 WO 2016080115 A1 WO2016080115 A1 WO 2016080115A1 JP 2015079134 W JP2015079134 W JP 2015079134W WO 2016080115 A1 WO2016080115 A1 WO 2016080115A1
Authority
WO
WIPO (PCT)
Prior art keywords
positive electrode
metal
air battery
ceramic
catalyst layer
Prior art date
Application number
PCT/JP2015/079134
Other languages
French (fr)
Japanese (ja)
Inventor
慶介 府金
崇介 西浦
和也 亀山
岳弘 清水
正信 相澤
Original Assignee
日立造船株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2015068952A external-priority patent/JP6596213B2/en
Application filed by 日立造船株式会社 filed Critical 日立造船株式会社
Priority to US15/527,243 priority Critical patent/US20170338536A1/en
Publication of WO2016080115A1 publication Critical patent/WO2016080115A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/443—Particulate material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M12/00—Hybrid cells; Manufacture thereof
    • H01M12/08—Hybrid cells; Manufacture thereof composed of a half-cell of a fuel-cell type and a half-cell of the secondary-cell type
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H01M50/491—Porosity
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a metal-air battery.
  • a metal-air battery in which a separator is disposed between a negative electrode and a positive electrode is known.
  • a separator main body that is a porous support formed of ceramic, and a negative electrode in the separator main body A porous film formed of ceramic on the opposing surface and having an average pore diameter smaller than the average pore diameter of the separator body is provided.
  • the separator includes a porous film formed of a ceramic material and a binder, and the binder is made of an acrylic rubber having a three-dimensional crosslinked structure.
  • Japanese Patent Application Laid-Open No. 2005-190833 discloses a battery for a secondary battery using a composition that works effectively for oxygen reduction and a composition that works effectively for oxygen generation by changing the composition of the perovskite oxide. An electrode is disclosed. Furthermore, Japanese Patent Application Laid-Open No.
  • 2004-265739 discloses a fuel battery cell in which the oxygen electrode layer has a two-layer structure, and the oxygen electrode layer has a conductive particle having an average particle diameter of 2 ⁇ m or less.
  • the reaction layer is composed of fine particles of conductive ceramic and the gas supply layer is composed of coarse particles of conductive ceramic having an average particle size of 10 to 100 ⁇ m.
  • a positive electrode conductive layer or a positive electrode catalyst layer is formed by forming a film containing a predetermined ceramic on the surface of the support and firing it.
  • a metal-air battery in order to increase the thickness of the positive electrode, it is necessary to repeat film formation and firing, and it takes a long time to manufacture the metal-air battery.
  • cracking or peeling occurs during firing. Therefore, in a metal-air battery using a separator as a support, it is difficult to increase the thickness of the positive electrode, and the battery performance cannot be improved by reducing the electrical resistance of the positive electrode.
  • the present invention is directed to a metal-air battery and aims to improve battery performance.
  • a metal-air battery according to the present invention includes a cylindrical positive electrode, a negative electrode facing an inner surface or an outer surface of the positive electrode, and an electrolyte layer disposed between the negative electrode and the positive electrode.
  • a porous positive electrode body which is a cylindrical support formed of conductive ceramic is provided, and a porous film is formed of ceramic on the inner or outer surface of the positive electrode body.
  • the positive electrode body as a support, the positive electrode can be easily thickened, the electric resistance of the positive electrode can be lowered, and the battery performance can be improved.
  • the porous film is a separator formed of the insulating ceramic on the surface of the positive electrode body on the negative electrode side.
  • the thickness of the positive electrode main body is larger than the thickness of the separator.
  • another porous film as a positive electrode catalyst layer is formed of ceramic on a surface of the positive electrode body opposite to the negative electrode, and the porous film is formed on the inner surface of the positive electrode body,
  • One porous film may be formed on the outer surface of the positive electrode body.
  • the porous membrane is a positive electrode catalyst layer formed on a surface of the positive electrode body opposite to the negative electrode.
  • the ceramic of the positive electrode catalyst layer may have the same crystal structure as that of the conductive ceramic of the positive electrode body.
  • the ceramic of the positive electrode catalyst layer is superior in oxygen reduction reaction than the conductive ceramic of the positive electrode body, and the conductive ceramic of the positive electrode body is more oxygen generating than the ceramic of the positive electrode catalyst layer. Excellent.
  • an average particle diameter of the conductive ceramic of the positive electrode body is 0.1 micrometer or more and 2 micrometers or less. In another aspect, the average particle size of the ceramic of the positive electrode catalyst layer is not less than 1 micrometer and not more than 10 micrometers. Preferably, the thickness of the positive electrode catalyst layer is not less than 0.4 times and not more than 2.3 times the thickness of the positive electrode body.
  • FIG. 1 is a diagram showing a configuration of a metal-air battery 1 according to an embodiment of the present invention.
  • the metal-air battery 1 in FIG. 1 is a secondary battery that uses zinc ions, and is a zinc-air secondary battery.
  • the metal-air battery may utilize other metal ions.
  • the main body 11 of the metal-air battery 1 has a substantially cylindrical shape with the central axis J1 as the center.
  • FIG. 1 shows a cross section of the main body 11 in a plane perpendicular to the central axis J1 (excluding the negative electrode 3 described later).
  • the metal-air battery 1 includes a positive electrode 2, a negative electrode 3, and an electrolyte layer 4.
  • the negative electrode 3 (also referred to as a metal electrode) is a coiled member centered on the central axis J1.
  • the negative electrode 3 in the present embodiment has a shape in which a linear member having a substantially circular cross section is spirally wound around the central axis J1.
  • the negative electrode 3 includes a coiled base material formed of a conductive material and a deposited metal layer formed on the surface of the base material.
  • a negative electrode current collector terminal (not shown) is connected to the end of the negative electrode 3 in the direction of the central axis J1.
  • the base material is formed of copper. From the viewpoint of increasing the conductivity of the base material also serving as a current collector, the base material preferably contains copper or a copper alloy.
  • a protective film of other metal such as nickel is formed on the surface of the main body. In this case, the surface of the substrate is the surface of the protective film.
  • the thickness of the protective film is 1 to 20 ⁇ m (micrometer), and the protective film is formed by plating.
  • the deposited metal layer is formed by electrolytic deposition of zinc (Zn).
  • the deposited metal layer may be formed by electrolytic deposition of an alloy containing zinc.
  • a cylindrical or rod-shaped negative electrode 3 may be used.
  • a cylindrical separator 41 is provided around the negative electrode 3, and a cylindrical positive electrode 2 (also referred to as an air electrode) is provided around the separator 41. That is, the inner surface of the separator 41 faces the negative electrode 3, and the outer surface of the separator 41 faces the inner surface of the positive electrode 2.
  • the negative electrode 3, the separator 41, and the positive electrode 2 are provided concentrically with the central axis J1 as the center, and when viewed along the central axis J1, the distance between the outer edge of the negative electrode 3 and the positive electrode 2 is the central axis. It is constant over the entire circumference in the circumferential direction centered on J1. That is, between the negative electrode 3 and the positive electrode 2 in the metal-air battery 1, the equipotential surface interval is constant over the entire circumference.
  • the shape of the positive electrode 2 may be, for example, a regular polygonal cylinder having six or more vertices. Details of the separator 41 will be described later.
  • the positive electrode 2 includes a porous positive electrode main body 21 that is a cylindrical support formed of a conductive ceramic, and a positive electrode catalyst layer 22 formed on the outer surface of the positive electrode main body 21 opposite to the negative electrode 3. Have. Preferably, the positive electrode catalyst layer 22 is formed over the entire circumference of the positive electrode main body 21.
  • An interconnector 24 made of ceramic having alkali resistance is provided on a part of the outer surface of the positive electrode catalyst layer 22. The thickness of the interconnector 24 is, for example, about 30 to 300 ⁇ m.
  • a positive current collector terminal (not shown) is connected to the interconnector 24.
  • a region not covered with the interconnector 24 has a water-repellent material (for example, FEP (tetrafluoroethylene / hexafluoropropylene copolymer) or PTFE (polytetrafluoroethylene). )) Is formed as the liquid repellent layer 29.
  • the liquid repellent layer 29 has high gas permeability and high liquid impermeability.
  • the positive electrode main body 21 which is a positive electrode conductive layer is formed by extrusion molding and firing of a material containing a conductive ceramic.
  • a conductive ceramic a perovskite oxide or spinel oxide having conductivity is preferably used.
  • the positive electrode body 21 is made of a perovskite oxide (for example, LSM (LaSrMnO 3 ), LSMF (LaSrMnFeO 3 ), or LSCF (LaSrCoFeO 3 )).
  • the perovskite oxide used in the positive electrode body 21 preferably contains at least one of Co, Mn, and Fe. From the viewpoint of preventing deterioration due to oxidation during charging, the positive electrode body 21 preferably does not contain conductive carbon.
  • the positive electrode main body 21 may be formed of other conductive ceramics.
  • the gas permeation amount of the positive electrode main body 21 is preferably 2000 m 3 / (m 2 ⁇ h ⁇ atm) or more.
  • the porosity of the positive electrode main body 21 is preferably 30% or more. When the porosity is smaller than 30%, the gas permeability is excessively lowered. Further, the porosity of the positive electrode main body 21 is preferably 80% or less. When the porosity is larger than 80%, the strength of the positive electrode body 21 as a support is lowered.
  • the positive electrode catalyst layer 22 is a portion in which a conductive ceramic powder such as a perovskite oxide (for example, LSM, LSCF, or LSMF) is supported on the positive electrode body 21 by, for example, a slurry coating method and firing. including.
  • the positive electrode catalyst layer 22 is a porous film formed of ceramic on the outer surface of the positive electrode main body 21 opposite to the negative electrode 3 and is supported by the positive electrode main body 21 as a support.
  • the thickness of the positive electrode catalyst layer 22 is sufficiently smaller than the thickness of the positive electrode main body 21.
  • an interface between air and an electrolyte solution 40 described later is formed in the vicinity of the porous positive electrode catalyst layer 22.
  • the separator 41 described above is a porous film formed on the inner surface of the positive electrode body 21 on the negative electrode 3 side, and is formed over the entire circumference of the inner surface.
  • the separator 41 is, for example, mechanical strength and insulation such as silica (SiO 2 ), alumina (Al 2 O 3 ), zirconia (ZrO 2 ), titania (TiO 2 ), hafnia (HfO 2 ), and ceria (CeO 2 ). It is a sintered body of ceramic powder with high properties and has alkali resistance.
  • a slurry containing the ceramic powder and the binder is formed on the inner surface of the positive electrode body 21 by a slurry coating method and dried, and the binder contained in the slurry is removed by high-temperature firing. Is done. This prevents the life of the separator from being shortened due to the deterioration of the binder.
  • the separator 41 is preferably composed only of ceramic.
  • the separator 41 may be a mixture or laminate of these ceramics.
  • the average particle size of the ceramic powder is preferably 0.1 ⁇ m or more and 30 ⁇ m or less, and the particle size is adjusted by classification as necessary.
  • the average pore diameter of the separator 41 is preferably 0.01 ⁇ m or more and 2 ⁇ m or less. Thereby, the deposited metal (dendrites or the like) of the negative electrode 3 is prevented from penetrating the separator 41.
  • the average pore diameter of the separator 41 is preferably smaller than the average pore diameter of the positive electrode body 21.
  • the thickness (wall thickness) of the cylindrical separator 41 is 50 ⁇ m or more and 200 ⁇ m or less, and is preferably smaller than the thickness of the positive electrode body 21.
  • the space inside the cylindrical positive electrode 2 (center axis J1 side) is filled with an aqueous electrolyte 40.
  • the electrolytic solution 40 is interposed between the positive electrode 2 and the negative electrode 3 and is in contact with both electrodes. About the entire negative electrode 3 is immersed in the electrolytic solution 40.
  • the electrolyte 40 is also filled in the porous separator 41 and the pores of the positive electrode main body 21. Further, the electrolyte solution 40 is also filled in some of the pores of the positive electrode catalyst layer 22.
  • the space between the negative electrode 3 and the positive electrode 2 when viewed along the central axis J1 is referred to as “electrolyte layer 4”. That is, the electrolyte layer 4 is disposed between the negative electrode 3 and the positive electrode 2.
  • the electrolyte layer 4 includes a separator 41.
  • the electrolytic solution 40 is an alkaline aqueous solution, and preferably contains a potassium hydroxide (caustic potash, KOH) aqueous solution or a sodium hydroxide (caustic soda, NaOH) aqueous solution. Further, the electrolytic solution 40 includes zinc ions or ions containing zinc. That is, the zinc ions contained in the electrolytic solution 40 may exist in various forms and may be regarded as ions containing zinc (that is, zinc atoms). For example, it may exist as tetrahydroxyzinc ions.
  • Disc-shaped blocking members are fixed to both end faces of the negative electrode 3, the electrolyte layer 4, and the positive electrode 2 in the direction of the central axis J1.
  • a through hole is provided in the center of each closing member.
  • the liquid repellent layer 29 and the closing member prevent the electrolytic solution 40 in the main body 11 from leaking outside the through hole. Moreover, it is possible to circulate electrolyte solution between the main body 11 and the storage tank not shown using the through-hole of the obstruction
  • the negative electrode current collector terminal and the positive electrode current collector terminal are electrically connected via a load such as a lighting fixture, for example.
  • Zinc included in the negative electrode 3 is oxidized to generate zinc ions, and electrons are supplied to the positive electrode 2 via the negative electrode current collector terminal and the positive electrode current collector terminal.
  • oxygen in the air that has passed through the liquid repellent layer 29 is reduced by the electrons supplied from the negative electrode 3 and is eluted into the electrolyte as hydroxide ions.
  • the reduction reaction of oxygen is promoted by the positive electrode catalyst.
  • the metal-air battery 1 when the metal-air battery 1 is charged, a voltage is applied between the negative electrode current collector terminal and the positive electrode current collector terminal, and electrons are supplied from the hydroxide ions to the positive electrode 2 and oxygen is added. Occurs. In the negative electrode 3, the metal ions are reduced by the electrons supplied to the negative electrode current collector terminal via the positive electrode current collector terminal, and zinc is deposited.
  • the coiled negative electrode 3 has no corners, so that electric field concentration hardly occurs. That is, there is no significant bias in current density. Further, the negative electrode 3 is in uniform contact with the electrolytic solution 40. As a result, the generation and growth of dendrites in which zinc precipitates in a dendritic shape and whiskers in which the zinc precipitates in a whisker shape (needle shape) are greatly suppressed. Actually, dense zinc is uniformly deposited on almost the entire surface of the negative electrode 3 to form a deposited metal layer. In the positive electrode 2, the generation of oxygen is promoted by the positive electrode catalyst contained in the positive electrode catalyst layer 22. Furthermore, since the positive electrode 2 does not use a carbon material, oxidative deterioration due to oxygen generated during charging does not occur.
  • FIG. 2 is a diagram showing a flow of manufacturing the positive electrode 2 provided with the separator 41.
  • FIG. 2 shows a basic flow of manufacturing the positive electrode 2, and the processing order may be changed as appropriate.
  • the cylindrical positive electrode main body 21 is formed as a porous support by extrusion molding and baking of a positive electrode forming material containing a conductive ceramic (step S11).
  • a conductive ceramic for example, a perovskite oxide is used, and here, LSM or LSCF is used. From the viewpoint of ensuring high conductivity in the positive electrode main body 21 which is the positive electrode conductive layer and also ensuring the function as an oxygen generation reaction catalyst, it is preferable to use LSCF.
  • the molded body Prior to firing, the molded body may be heat-treated at 100 to 800 ° C. to decompose and remove organic components in the molded body.
  • the firing may be performed under conditions that allow the molded body to be sufficiently sintered and maintain gas permeability, electrolyte solution permeability, and battery performance, and is preferably performed at 900 to 1500 ° C.
  • the adhesive strength between the molded body and the layer can be improved.
  • the lead time of a baking process can be reduced compared with the case where each layer is baked separately.
  • the positive electrode main body 21 may be formed by a technique other than extrusion molding and baking.
  • a slurry containing a positive electrode catalyst is formed on the outer surface of the positive electrode main body 21 by a slurry coating method, and baked together with the positive electrode main body 21, thereby forming the positive electrode catalyst layer 22 (step S12). ).
  • a ceramic such as a perovskite oxide is used.
  • LSM, LSCF, or LSMF is used.
  • the ceramic of the positive electrode catalyst layer 22 has the same crystal structure as the conductive ceramic forming the positive electrode main body 21, the difference in thermal expansion coefficient between the positive electrode main body 21 and the positive electrode catalyst layer 22 is reduced, and cracks due to firing And the occurrence of peeling are suppressed.
  • a casting method such as a casting method, a dipping method, a spray method, and a printing method can be used for forming a slurry film (film formation).
  • the film thickness of each layer in the positive electrode 2 is appropriately adjusted in consideration of maintaining characteristics related to battery performance such as gas permeability and electrolyte solution permeability, and firing shrinkage during firing.
  • the positive electrode catalyst layer 22 may be formed by a method other than the above film formation and baking (the same applies to the interconnector 24, the separator 41, and the liquid repellent layer 29).
  • the positive electrode catalyst layer 22 When the positive electrode catalyst layer 22 is formed, masking is performed on the outer surface of the positive electrode catalyst layer 22 except for a part of the region. Subsequently, using a slurry containing fine powder such as a perovskite oxide, a film is formed on the region by a slurry coating method, and the film is baked together with the positive electrode body 21 and the positive electrode catalyst layer 22, The interconnector 24 is formed (step S13).
  • a slurry containing a separator forming material is formed on the inner surface of the positive electrode body 21 by a slurry coating method, and fired together with the positive electrode body 21, the positive electrode catalyst layer 22, and the interconnector 24. 41 is formed (step S14).
  • the separator forming material for example, an insulating ceramic is used, and here, alumina or zirconia is used. In firing the separator 41, it is preferable that the binder contained in the slurry is removed.
  • a slurry containing a liquid repellent material is formed on the outer surface of the positive electrode catalyst layer 22 by a slurry coating method, and fired together with the positive electrode main body 21, the positive electrode catalyst layer 22, the interconnector 24, and the separator 41.
  • the liquid repellent layer 29 is formed (step S15).
  • the liquid repellent material for example, FEP or PTFE is used.
  • the penetration depth to the depth direction of the positive electrode catalyst layer 22 is adjusted by adjusting a slurry viscosity by adding a required amount of thickeners to a slurry. Thereby, the three-phase interface can be formed in the vicinity of the positive electrode catalyst layer 22 in the metal-air battery 1 while preventing the particle surfaces in the pores of the positive electrode catalyst layer 22 from being completely covered with the liquid repellent material. Realized.
  • FIG. 3 is a diagram showing a configuration of the metal-air battery 9 of the comparative example, and is a cross-sectional view corresponding to FIG.
  • the separator 94 formed of alumina is a cylindrical support, and the positive electrode conductive layer 921 of the positive electrode 92 and the like are provided on the outer surface of the separator 94.
  • the positive electrode 92 is formed to have a predetermined thickness by repeating film formation and firing of a slurry containing a perovskite oxide by a slurry coating method a plurality of times.
  • the thickness of the positive electrode 92 in order to increase the thickness of the positive electrode 92, it is necessary to repeat film formation and firing many times, so that the manufacture of the metal-air battery 9 (the positive electrode 92) becomes complicated. Further, cracks and peeling of the positive electrode 92 are likely to occur. Actually, there is a certain limit in increasing the thickness of the positive electrode 92 in consideration of the manufacturing cost and the like. Therefore, in the metal-air battery 9 of the comparative example, the thickness of the positive electrode 92 is relatively thin. As a result, the electrical resistance of the positive electrode 92 is increased, and it is difficult to improve battery performance.
  • the positive electrode 2 includes a porous positive electrode body 21 that is a cylindrical support formed of a conductive ceramic, and an insulating surface is provided on the inner surface of the positive electrode body 21.
  • a separator 41 which is a porous film made of ceramic, is provided.
  • the separator 41 can be made much thinner than the metal-air battery 9 of the comparative example using the separator 94 as a support.
  • the distance between the negative electrode 3 and the positive electrode 2 can be reduced, and the battery performance of the metal-air battery 1 can be further improved.
  • production of the crack in the formation of the separator 41 and peeling can also be suppressed.
  • the thickness of the positive electrode main body 21 is larger than the thickness of the separator 41, the distance between the negative electrode 3 and the positive electrode 2 is reduced while reducing the electrical resistance of the positive electrode 2.
  • the battery performance of the metal-air battery 1 can be further improved.
  • the thickness of the positive electrode main body 21 is preferably larger than 3 times the thickness of the separator 41, more preferably larger than 5 times.
  • the positive electrode catalyst layer 22 can be regarded as a discharge reaction layer, and the positive electrode catalyst layer 22 is preferably formed of a ceramic superior in oxygen reduction reaction than the conductive ceramic forming the positive electrode body 21. .
  • the active material is efficiently supplied to the catalyst by using a catalyst for the oxygen reduction reaction for the positive electrode catalyst layer 22 in contact with oxygen which is an active material for the oxygen reduction reaction. The Thereby, concentration overvoltage can be reduced and the discharge performance in the metal-air battery 1 can be improved.
  • the positive electrode main body 21 can be regarded as a charge reaction layer, and the positive electrode main body 21 is preferably formed of a conductive ceramic superior in oxygen generation reaction than the ceramic forming the positive electrode catalyst layer 22.
  • a catalyst for oxygen generation reaction in the positive electrode main body 21 filled with hydroxide ions (including an electrolyte) that is an active material for oxygen generation reaction among the positive electrode main body 21 and the positive electrode catalyst layer 22 The active material is efficiently supplied to the catalyst. Thereby, concentration overvoltage can be reduced and the charging performance in the metal-air battery 1 can be improved.
  • the superiority or inferiority of the oxygen reduction reaction and the oxygen generation reaction can be evaluated, for example, by the technique described in JP-A-2005-190833 (Document 3). That is, a gas diffusion electrode using various materials as a catalyst is formed, an oxygen reduction reaction and an oxygen generation reaction are caused, and a voltage with respect to a reference electrode showing a predetermined electrode current density is measured.
  • a gas diffusion electrode using various materials as a catalyst is formed, an oxygen reduction reaction and an oxygen generation reaction are caused, and a voltage with respect to a reference electrode showing a predetermined electrode current density is measured.
  • the oxygen reduction reaction it can be said that the material with a higher voltage has a better oxygen reduction reaction, and in the oxygen generation reaction, the material with a lower voltage has a better oxygen generation reaction.
  • a preferred material for the positive electrode catalyst layer 22 and the positive electrode body 21 is a perovskite oxide.
  • the perovskite oxide is represented by ABO 3 where A is an alkali metal, alkaline earth metal, or rare earth metal, and B is a transition metal.
  • a preferred material for the positive electrode catalyst layer 22 is a perovskite oxide, wherein the A site is composed of at least one of La, Sr, and Ca, and the B site is composed of at least one of Fe, Ni, Co, and Mn.
  • a preferable material for the positive electrode body 21 is a perovskite oxide, in which the A site is composed of at least one of La and Sr, and the B site is composed of at least one of Co and Fe. Preferably different).
  • the ceramic of the positive electrode catalyst layer 22 is more than the ceramic of the positive electrode body 21.
  • the oxygen reduction reaction is excellent, and the ceramic of the positive electrode main body 21 is superior in the oxygen generation reaction than the ceramic of the positive electrode catalyst layer 22.
  • the average particle diameter of the ceramic particles constituting the positive electrode catalyst layer 22 is preferably 1 ⁇ m or more in order to ensure a certain gas diffusibility in the discharge reaction, and 10 ⁇ m or less in order to ensure a certain reaction area. It is preferable that Thereby, the discharge performance in a metal air battery can further be improved.
  • the average particle diameter of the conductive ceramic particles constituting the positive electrode body 21 is preferably 0.1 ⁇ m or more in order to secure pores of a size sufficient to hold the electrolyte solution. In order to ensure a certain reaction area in the case, it is preferably 2 ⁇ m or less. Thereby, the charge performance in a metal air battery can further be improved.
  • the average particle diameter of the ceramic particles is obtained by using an intercept method in an image of a smooth surface obtained by polishing the cross section of the positive electrode 2 using a scanning electron microscope, for example.
  • Example 1 Based on a cylindrical perovskite oxide porous ceramic support tube (LSM, average pore diameter 5 ⁇ m) manufactured by Hitachi Zosen Corporation with a thickness of 2 mm, an outer diameter of 16 mm, an inner diameter of 12 mm, and a length of 70 mm obtained by extrusion molding and high-temperature firing As described below, a positive electrode (air electrode) provided with a separator was produced by performing film formation and baking in the order of processes having a high baking temperature while using a slurry coating method.
  • the ceramic support tube is referred to as “ceramic tube”.
  • the first-layer and second-layer separator film-forming slurries were prepared as follows. To a solution obtained by adding 1- (2-n-butoxyethoxy) ethyl acetate to alcohol 3 (Solmix (registered trademark)), stir 3.4% by weight of binder (ethylcellulose) so as not to become a mass. While adding little by little. Stirring was performed until the binder dissolved and the solution became transparent.
  • the solution obtained as described above was previously placed in a pot mill container in which 32% by weight of alumina powder (for example, A-42-6 manufactured by Showa Denko KK) and ⁇ 10 mm resin balls were placed, and the ball mill was used for 10 days or more. The mixture was stirred.
  • alumina powder for example, A-42-6 manufactured by Showa Denko KK
  • the slurry for the catalyst layer was prepared as follows. To a solution of alcohol (Solmix (registered trademark) H-37) 3 with 1 2- (2-n-butoxyethoxy) ethyl acetate added, 3.4% by weight of binder (ethylcellulose) should not be agglomerated. Was added in small portions with stirring and stirred until dissolved. The solution obtained as described above was placed in a pot mill container in which 32% by weight of LaSrCoFeO 3 raw material powder and ⁇ 10 mm resin balls were previously placed, and mixed and stirred by a ball mill for 10 days or more.
  • solvent Solmix (registered trademark) H-37) 3 with 1 2- (2-n-butoxyethoxy) ethyl acetate added
  • binder ethylcellulose
  • An interconnector film-forming slurry was prepared by the following procedure. To a solution obtained by adding 2- (2-n-butoxyethoxy) ethyl acetate (manufactured by Kanto Chemical Co., Inc.) 1 to Solmix (registered trademark) H-37 (manufactured by Nippon Alcohol Sales Co., Ltd.) 4 wt% A binder (ethyl cellulose (manufactured by Tokyo Chemical Industry Co., Ltd.)) was added little by little with stirring so as not to clump, and stirred until dissolved.
  • 2- (2-n-butoxyethoxy) ethyl acetate manufactured by Kanto Chemical Co., Inc.
  • Solmix registered trademark
  • H-37 manufactured by Nippon Alcohol Sales Co., Ltd.
  • a binder ethyl cellulose (manufactured by Tokyo Chemical Industry Co., Ltd.)) was added little by little with stirring so as not to clump, and stirred until dissolved.
  • the solution obtained as described above was placed in a pot mill container together with 27% by weight of LaSrCoFeO 3 (LSCF) powder having an average particle size of 3.7 ⁇ m and a resin ball of ⁇ 10 mm, and mixed in a ball mill for 50 hours to prepare an interconnector slurry. Obtained.
  • LSCF LaSrCoFeO 3
  • the third-layer and fourth-layer separator film-forming slurries were prepared as follows. To a solution obtained by adding 1- (2-n-butoxyethoxy) ethyl acetate to alcohol (Solmix (registered trademark)) 3, 2.9% by weight of binder (ethylcellulose) was stirred so as not to clump. While adding little by little. Stirring was performed until the binder dissolved and the solution became transparent. The solution obtained as described above is placed in a nylon resin pot container in which 20% by weight of zirconia powder (for example, TZ-0 manufactured by Tosoh Corporation) and a ⁇ 10 mm nylon resin ball are placed in advance, and the ball mill is used for 10 days or more. The mixture was stirred.
  • zirconia powder for example, TZ-0 manufactured by Tosoh Corporation
  • the ceramic tube was mounted with a hose-like cap at the upper end and a sealing plug at the lower end in the same manner upside down from when the third layer was formed.
  • the same slurry as that used in the third-layer film formation was poured from the upper end of the ceramic tube with a hose-shaped cap, and the slurry was held for 1 minute while filling up to the upper part of the ceramic tube.
  • the sealing plug at the lower end was removed and the slurry was removed. Then, it dried at room temperature for 15 hours or more, and was dried at 50 degreeC for 2 hours or more.
  • the dried ceramic tube was baked at 1000 ° C. for 4 hours to obtain a ceramic tube in which four layers of films (two layers of alumina film and two layers of zirconia film) were laminated on the inner surface.
  • the interconnector part of the ceramic tube is covered with tape so that the width of the part where the liquid repellent layer (water repellent layer) overlaps with the interconnector is 1 mm, immersed in the above-mentioned dispersion for 1 minute, room temperature, 30 minutes,
  • the ceramic tube in which the liquid repellent layer was formed was obtained by drying at 60 ° C. for 15 hours and firing at 280 ° C. for 50 minutes.
  • sample test The obtained sample was evaluated for gas permeation performance by an N 2 gas permeation test, and was evaluated for water pressure resistance by a water pressure resistance test.
  • the gas permeation performance of the cylindrical perovskite oxide porous ceramic tube was 2027 m 3 / (m 2 ⁇ h ⁇ atm), whereas the separator, the positive electrode catalyst layer, the interconnector and the liquid repellent layer were formed.
  • the gas permeation performance was 117 m 3 / (m 2 ⁇ h ⁇ atm).
  • water leakage was confirmed at 0.045 MPa.
  • ⁇ Comparative Example 1> Based on a cylindrical alumina porous ceramic tube (Al 2 O 3 , average pore diameter of 10 ⁇ m) made by Hitachi Zosen with a thickness of 2 mm, an outer diameter of 16 mm, an inner diameter of 12 mm, and a length of 70 mm obtained by extrusion molding and high-temperature firing As described below, a positive electrode of a comparative example was manufactured by performing film formation and baking in the order of processes having a high baking temperature while using a slurry coating method. Note that the positive electrode of the comparative example is provided with a buffer layer that suppresses the formation of a reaction phase at the interface between a conductive layer and a separator described later.
  • the buffer layer slurry was prepared as follows. To a solution of alcohol (Solmix (registered trademark) H-37) 3 with 1 2- (2-n-butoxyethoxy) ethyl acetate added, 3.4% by weight of binder (ethylcellulose) should not be agglomerated. Was added in small portions with stirring and stirred until dissolved. The solution obtained as described above was put in a pot mill container in which 32% by weight of LaSrCoMnFeO 3 raw material powder and ⁇ 10 mm resin balls were previously placed, and mixed and stirred for 10 days or more by a ball mill.
  • solvent Solmix (registered trademark) H-37) 3 with 1 2- (2-n-butoxyethoxy) ethyl acetate added
  • binder ethylcellulose
  • the slurry for conductive layers was prepared as follows. To a solution of alcohol (Solmix (registered trademark) H-37) 3 with 1 2- (2-n-butoxyethoxy) ethyl acetate added, 3.4% by weight of binder (ethylcellulose) should not be agglomerated. Was added in small portions with stirring and stirred until dissolved. The solution obtained as described above was placed in a pot mill container in which 32% by weight of LaSrCoFeO 3 raw material powder and ⁇ 10 mm resin balls were previously placed, and mixed and stirred by a ball mill for 10 days or more.
  • solvent Solmix (registered trademark) H-37) 3 with 1 2- (2-n-butoxyethoxy) ethyl acetate added
  • binder ethylcellulose
  • the slurry for the catalyst layer was prepared as follows. To a solution of alcohol (Solmix (registered trademark) H-37) 3 with 1 2- (2-n-butoxyethoxy) ethyl acetate added, 3.4% by weight of binder (ethylcellulose) should not be agglomerated. Was added in small portions with stirring and stirred until dissolved. The solution obtained as described above was placed in a pot mill container in which 32% by weight of LaSrMnFeO 3 raw material powder and ⁇ 10 mm resin balls were previously placed, and mixed and stirred for 10 days or more in a ball mill.
  • solvent Solmix (registered trademark) H-37) 3 with 1 2- (2-n-butoxyethoxy) ethyl acetate added
  • binder ethylcellulose
  • the ceramic tube was immersed in the slurry for the conductive layer to the upper end thereof and held for 1 minute. After 1 minute, the ceramic tube was pulled up from the slurry, and the slurry was dripped down. Then, it dried at 35 degreeC for 30 minutes or more, and was dried at 80 degreeC for 90 minutes or more.
  • the ceramic tube (support) after the immersion and drying of the buffer layer and the conductive layer three times in total was fired at 1325 ° C. for 4 hours.
  • the ceramic tube was held in the slurry for the conductive layer for 1 minute in a state where the ceramic tube was immersed up to its upper end. After 1 minute, the ceramic tube was pulled up from the slurry, and the slurry was dripped down. Then, it dried at 35 degreeC for 30 minutes or more, and was dried at 80 degreeC for 90 minutes or more. The ceramic tube after repeating this operation three times was fired at 1325 ° C. for 4 hours.
  • the ceramic tube was held in the slurry for the conductive layer for 1 minute in a state where the ceramic tube was immersed up to its upper end. After 1 minute, the ceramic tube was pulled up from the slurry, and the slurry was dripped down. Then, it dried at 35 degreeC for 30 minutes or more, and was dried at 80 degreeC for 90 minutes or more. After this operation was repeated three times, the ceramic tube was continuously held in the slurry for the catalyst layer for 1 minute in a state where the ceramic tube was immersed up to its upper end. After 1 minute, the ceramic tube was pulled up from the slurry, and the slurry was dripped down. Then, it dried at 35 degreeC for 30 minutes or more, and was dried at 80 degreeC for 90 minutes or more. The ceramic tube after the immersion and drying of the conductive layer and the catalyst layer four times in total was fired at 1325 ° C. for 4 hours.
  • the first-layer and second-layer separator film-forming slurries were prepared as follows. To a solution obtained by adding 1- (2-n-butoxyethoxy) ethyl acetate to alcohol 3 (Solmix (registered trademark)), stir 3.4% by weight of binder (ethylcellulose) so as not to become a mass. While adding little by little. Stirring was performed until the binder dissolved and the solution became transparent.
  • the solution obtained as described above was previously placed in a pot mill container in which 32% by weight of alumina powder (for example, A-42-6 manufactured by Showa Denko KK) and ⁇ 10 mm resin balls were placed, and the ball mill was used for 10 days or more. The mixture was stirred.
  • alumina powder for example, A-42-6 manufactured by Showa Denko KK
  • the pore diameter of the alumina film is smaller than the pore diameter of the ceramic tube, and the alumina film is for preventing penetration of dendrites (the same applies to the zirconia film described later).
  • An interconnector film-forming slurry was prepared by the following procedure. To a solution obtained by adding 2- (2-n-butoxyethoxy) ethyl acetate (manufactured by Kanto Chemical Co., Inc.) 1 to Solmix (registered trademark) H-37 (manufactured by Nippon Alcohol Sales Co., Ltd.) 4 wt% A binder (ethyl cellulose (manufactured by Tokyo Chemical Industry Co., Ltd.)) was added little by little with stirring so as not to clump, and stirred until dissolved.
  • 2- (2-n-butoxyethoxy) ethyl acetate manufactured by Kanto Chemical Co., Inc.
  • Solmix registered trademark
  • H-37 manufactured by Nippon Alcohol Sales Co., Ltd.
  • a binder ethyl cellulose (manufactured by Tokyo Chemical Industry Co., Ltd.)) was added little by little with stirring so as not to clump, and stirred until dissolved.
  • the solution obtained as described above was placed in a pot mill container together with 27% by weight of LaSrCoFeO 3 powder having an average particle diameter of 3.7 ⁇ m and a resin ball of ⁇ 10 mm, and mixed in a ball mill for 50 hours to obtain an interconnector slurry.
  • the third-layer and fourth-layer separator film-forming slurries were prepared as follows. To a solution obtained by adding 1- (2-n-butoxyethoxy) ethyl acetate to alcohol (Solmix (registered trademark)) 3, 2.9% by weight of binder (ethylcellulose) was stirred so as not to clump. While adding little by little. Stirring was performed until the binder dissolved and the solution became transparent. The solution obtained as described above is placed in a nylon resin pot container in which 20% by weight of zirconia powder (for example, TZ-0 manufactured by Tosoh Corporation) and a ⁇ 10 mm nylon resin ball are placed in advance, and the ball mill is used for 10 days or more. The mixture was stirred.
  • zirconia powder for example, TZ-0 manufactured by Tosoh Corporation
  • the ceramic tube was mounted with a hose-like cap at the upper end and a sealing plug at the lower end in the same manner upside down from when the third layer was formed.
  • the same slurry as that used in the third-layer film formation was poured from the upper end of the ceramic tube with a hose-shaped cap, and the slurry was held for 1 minute while filling up to the upper part of the ceramic tube.
  • the sealing plug at the lower end was removed and the slurry was removed. Then, it dried at room temperature for 15 hours or more, and was dried at 50 degreeC for 2 hours or more.
  • the dried ceramic tube was baked at 1000 ° C. for 4 hours to obtain a ceramic tube in which four layers of films (two layers of alumina film and two layers of zirconia film) were laminated on the inner surface.
  • the interconnector part of the ceramic tube is covered with tape so that the width of the part where the liquid repellent layer overlaps the interconnector is 1 mm, and immersed in the above dispersion for 1 minute, at room temperature / 30 minutes, 60 ° C./15 hours
  • the ceramic tube which formed the liquid repellent layer by drying and baking at 280 degreeC for 50 minutes was obtained.
  • sample test The obtained sample was evaluated for gas permeation performance by an N 2 gas permeation test, and was evaluated for water pressure resistance by a water pressure resistance test.
  • the gas permeation performance of the cylindrical alumina porous ceramic tube was 3015 m 3 / (m 2 ⁇ h ⁇ atm), while the buffer layer, conductive layer, catalyst layer, separator, interconnector and liquid repellent layer were formed.
  • the gas permeation performance of the obtained ceramic tube was 93 m 3 / (m 2 ⁇ h ⁇ atm). Further, as a result of a water pressure test in which the inside of the ceramic tube was filled with water and was gradually pressurized with N 2 gas, water leakage was confirmed at 0.065 MPa.
  • FIG. 4 is a graph showing charge / discharge characteristics of a metal-air battery using the positive electrode of Example 1 and a metal-air battery using the positive electrode of Comparative Example 1.
  • FIG. 5 is a diagram showing the output density of the metal-air battery using the positive electrode of Example 1 and the metal-air battery using the positive electrode of Comparative Example 1.
  • the metal-air battery using the positive electrode of Example 1 that is, the positive electrode using the positive electrode body as a support
  • the metal using the positive electrode of Comparative Example 1 that is, the positive electrode using the separator as a support.
  • the discharge voltage is higher than that of the air battery (see L1 and L2 in FIG. 4) and the charge voltage is low (see L3 and L4 in FIG. 4).
  • the metal-air battery using the positive electrode of Example 1 has a higher output density than the metal-air battery using the positive electrode of Comparative Example 1.
  • the metal-air battery using the positive electrode of Example 1 has higher battery performance than the metal-air battery using the positive electrode of Comparative Example 1.
  • the time required for producing the positive electrode of Example 1 is about 2/3 of the time required for producing the positive electrode of the comparative example.
  • Example 2 LaSrMnO 3 (LSM) powder and LaSrCoFeO 3 (LSCF) powder (both manufactured by Kyoritsu Materials Co., Ltd.) were coarsely pulverized by a cutter mill and finely pulverized by a jet mill (Nisshin Engineering Co., Ltd.). Thereafter, classification was performed with a turbo classifier to obtain LSM powder and LSCF powder having various particle sizes. Then, according to the same method as in Example 1, the ceramic which is the positive electrode main body in the combination of the material (catalyst type) and the particle size (average particle size) described in the column of “Positive electrode main body (charge reaction layer)” in FIG.
  • LSM LaSrMnO 3
  • LSCF LaSrCoFeO 3
  • a tube was formed, and a positive electrode catalyst layer was formed on the outer surface of the ceramic tube with a combination of materials and particle sizes described in the column of “positive electrode catalyst layer (discharge reaction layer)”.
  • the ratio (T1: T2) between the thickness T1 of the positive electrode catalyst layer and the thickness T2 of the positive electrode main body (ceramic tube) is shown.
  • a Cu coil in which 2 g of Zn is electrodeposited is inserted as the negative electrode inside the positive electrode sample prepared as described above, and contains an electrolytic solution (7M (molar) KOH and 0.65M ZnO (zinc oxide)). ) was circulated inward, and the discharge and charge characteristics of the battery were measured at room temperature.
  • the number of the positive electrode sample is written in the leftmost column, and in the “discharge performance” and “charge performance” columns, in the metal-air battery using each sample, the output density is 10 mA / cm 2 . The voltage is shown.
  • ⁇ is marked when the voltage is 1.2 V or more, ⁇ is marked when the voltage is less than 1.2 V and 0.8 V or more, and less than 0.8 V and 0.6 V or more. ⁇ is marked in some cases.
  • “charging performance” when the voltage is 1.8 V or less, “ ⁇ ” is marked, and when it is larger than 1.8 V and 2.0 V or smaller, “ ⁇ ” is marked, and larger than 2.0 V. When it is 2 V or less, ⁇ is marked.
  • the discharge performance of the metal-air battery is improved when the average particle diameter of the particles forming the positive electrode catalyst layer is 1 ⁇ m or more and 10 ⁇ m or less.
  • the average particle size of the particles forming the positive electrode catalyst layer is preferably 2 ⁇ m or more.
  • the discharge performance is lowered due to the reduction of the reaction effective area. Therefore, from the viewpoint of securing higher discharge performance, it is preferable to secure a certain effective reaction area by setting the average particle diameter of the particles forming the positive electrode catalyst layer to 6 ⁇ m or less.
  • the average particle diameter of the particles forming the positive electrode main body may be 0.1 ⁇ m or more. Preferably, it is 0.2 ⁇ m or more. Further, from the results of the charging performance of the Nos. 3, 6 and 8 samples, it can be said that the charging performance of the metal-air battery is enhanced when the average particle diameter of the particles forming the positive electrode body is 2 ⁇ m or less. Since the charging performance is improved as the average particle size of the particles decreases, that is, by increasing the reaction effective area, the average particle size of the particles is more preferably 0.8 ⁇ m or less based on the above results. I can say that.
  • the preferable range of (D1 / D2) is 1 -100, and a more preferable range is 2-20. From the results of the charge and discharge performance of the samples 3, 10 and 11, the charge and discharge performance is lower in the thickness ratios of 1: 9 and 9: 1 than in the case of 5: 5. On the other hand, from the results of the charge and discharge performance of the samples 7 to 9, constant charge and discharge performance is maintained when the thickness ratio is 3: 7, 5: 5, and 7: 3.
  • the thickness of the positive electrode catalyst layer is 0.4 times or more (thickness ratio corresponding to 3: 7) and 2.3 times or less (thickness ratio corresponding to 7: 3) of the thickness of the positive electrode body. Preferably there is. Thereby, in a metal air battery, it becomes possible to ensure a certain amount of performance about both discharge and charge.
  • the metal-air battery 1 can be variously modified.
  • the negative electrode 3 may be provided around the cylindrical positive electrode 2. That is, the negative electrode 3 may be opposed to the inner surface or the outer surface of the positive electrode 2.
  • the separator 41 is provided on the outer surface of the positive electrode body 21.
  • the separator 41 may be prepared as a cylindrical independent member, and the member may be inserted into the positive electrode body 21 in which the positive electrode catalyst layer 22 is formed on the outer surface. . Further, depending on the battery performance required for the metal-air battery 1, only the separator 41 may be formed on the inner surface of the positive electrode body 21, and the positive electrode catalyst layer 22 may be omitted.
  • a porous film is formed of ceramic on the inner side surface or the outer side surface of the positive electrode main body 21 that is a cylindrical support, that is, the positive electrode main body 21 is formed of ceramic on the inner side surface or the outer side surface.
  • the positive electrode 2 By providing the formed porous film as a cylindrical member capable of supporting, the positive electrode 2 can be easily thickened, the electric resistance of the positive electrode 2 can be lowered, and the battery performance can be improved. If the occurrence of dendrite does not matter, the separator 41 may be omitted.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Inert Electrodes (AREA)
  • Hybrid Cells (AREA)

Abstract

This metal-air battery (1) is provided with: a cylindrical positive electrode (2); a negative electrode (3) that faces the inner surface of the positive electrode (2); and an electrolyte layer (4) that is arranged between the negative electrode (3) and the positive electrode (2). The positive electrode (2) is provided with a porous positive electrode main body (21) which is a cylindrical supporting body formed of a conductive ceramic, and a separator (41), which is a porous film formed of an insulating ceramic, is arranged on the inner surface of the positive electrode main body (21). By using the positive electrode main body (21) as a supporting body in this manner, the positive electrode (2) is able to be easily increased in the thickness, and the battery performance of the metal-air battery (1) is able to be improved by decreasing the electrical resistance of the positive electrode (2).

Description

金属空気電池Metal air battery
　本発明は、金属空気電池に関する。 The present invention relates to a metal-air battery.
　従来より、負極と正極との間にセパレータを配置した金属空気電池が知られている。例えば、特開２０１４－１９４８９７号公報（文献１）では、負極と正極との間に配置されるセパレータにおいて、セラミックにて形成される多孔質の支持体であるセパレータ本体と、セパレータ本体において負極と対向する面上にセラミックにて形成され、セパレータ本体の平均細孔径よりも小さい平均細孔径を有する多孔膜とが設けられる。文献１では、多孔膜の平均細孔径が、０．０１μｍ（マイクロメートル）以上かつ２μｍ以下であり、多孔膜の厚さが５０μｍ以上かつ２００μｍ以下であることにより、負極の析出金属がセパレータを貫通することが防止される。 Conventionally, a metal-air battery in which a separator is disposed between a negative electrode and a positive electrode is known. For example, in Japanese Patent Application Laid-Open No. 2014-194497 (Document 1), in a separator disposed between a negative electrode and a positive electrode, a separator main body that is a porous support formed of ceramic, and a negative electrode in the separator main body A porous film formed of ceramic on the opposing surface and having an average pore diameter smaller than the average pore diameter of the separator body is provided. In Reference 1, when the average pore diameter of the porous film is 0.01 μm (micrometer) or more and 2 μm or less, and the thickness of the porous film is 50 μm or more and 200 μm or less, the deposited metal of the negative electrode penetrates the separator. Is prevented.
　なお、特開２００６－３１０３０２号公報（文献２）におけるリチウム二次電池では、セパレータがセラミック物質とバインダとにより形成される多孔膜を含み、当該バインダが３次元架橋構造を有するアクリル系ゴムにて構成される。また、特開２００５－１９０８３３号公報（文献３）では、ペロブスカイト型酸化物の組成物を変えて、酸素還元に有効に働くものと、酸素発生に有効に働くものとを使用した二次電池用電極が開示されている。さらに、特開２００４－２６５７３９号公報（文献４）では、酸素極層が二層構造を有している燃料電池セルが開示されており、当該酸素極層は、平均粒径が２μｍ以下の導電性セラミックの微細粒子からなる反応層と、平均粒径が１０～１００μｍの導電性セラミックの粗大粒子からなるガス供給層とからなる。 In the lithium secondary battery disclosed in Japanese Patent Application Laid-Open No. 2006-310302 (Document 2), the separator includes a porous film formed of a ceramic material and a binder, and the binder is made of an acrylic rubber having a three-dimensional crosslinked structure. Composed. Japanese Patent Application Laid-Open No. 2005-190833 (Document 3) discloses a battery for a secondary battery using a composition that works effectively for oxygen reduction and a composition that works effectively for oxygen generation by changing the composition of the perovskite oxide. An electrode is disclosed. Furthermore, Japanese Patent Application Laid-Open No. 2004-265739 (Document 4) discloses a fuel battery cell in which the oxygen electrode layer has a two-layer structure, and the oxygen electrode layer has a conductive particle having an average particle diameter of 2 μm or less. The reaction layer is composed of fine particles of conductive ceramic and the gas supply layer is composed of coarse particles of conductive ceramic having an average particle size of 10 to 100 μm.
　ところで、セパレータを支持体とする金属空気電池では、例えば、支持体の表面に所定のセラミックを含む材料を成膜して焼成することにより、正極導電層や正極触媒層が形成される。このような金属空気電池において、正極の厚さを大きくする場合には、成膜および焼成を繰り返す必要があり、金属空気電池の製造に長時間を要してしまう。また、セパレータの材料と、正極導電層や正極触媒層の材料との間に大きな熱膨張係数差がある場合には、焼成の際に、クラックや剥離が生じてしまう。したがって、セパレータを支持体とする金属空気電池では、正極を厚くすることが困難であり、正極の電気抵抗を低くして電池性能を向上することができない。 By the way, in a metal-air battery using a separator as a support, for example, a positive electrode conductive layer or a positive electrode catalyst layer is formed by forming a film containing a predetermined ceramic on the surface of the support and firing it. In such a metal-air battery, in order to increase the thickness of the positive electrode, it is necessary to repeat film formation and firing, and it takes a long time to manufacture the metal-air battery. Further, when there is a large difference in thermal expansion coefficient between the material of the separator and the material of the positive electrode conductive layer or the positive electrode catalyst layer, cracking or peeling occurs during firing. Therefore, in a metal-air battery using a separator as a support, it is difficult to increase the thickness of the positive electrode, and the battery performance cannot be improved by reducing the electrical resistance of the positive electrode.
　本発明は、金属空気電池に向けられており、電池性能を向上することを目的としている。 The present invention is directed to a metal-air battery and aims to improve battery performance.
　本発明に係る金属空気電池は、筒状の正極と、前記正極の内側面または外側面に対向する負極と、前記負極と前記正極との間に配置される電解質層とを備え、前記正極が、導電性セラミックにて形成された筒状の支持体である多孔質の正極本体を有し、前記正極本体の内側面または外側面に多孔膜がセラミックにて形成される。 A metal-air battery according to the present invention includes a cylindrical positive electrode, a negative electrode facing an inner surface or an outer surface of the positive electrode, and an electrolyte layer disposed between the negative electrode and the positive electrode. A porous positive electrode body which is a cylindrical support formed of conductive ceramic is provided, and a porous film is formed of ceramic on the inner or outer surface of the positive electrode body.
　本発明によれば、正極本体を支持体とすることにより、正極を容易に厚くすることができ、正極の電気抵抗を低くして、電池性能を向上することができる。 According to the present invention, by using the positive electrode body as a support, the positive electrode can be easily thickened, the electric resistance of the positive electrode can be lowered, and the battery performance can be improved.
　本発明の一の好ましい形態では、前記多孔膜が、前記正極本体の前記負極側の面に、絶縁性の前記セラミックにて形成されたセパレータである。この場合に、前記正極本体の厚さが、前記セパレータの厚さよりも大きいことが好ましい。また、前記正極本体の前記負極とは反対側の面に、正極触媒層であるもう１つの多孔膜がセラミックにて形成され、前記多孔膜が前記正極本体の前記内側面に形成され、前記もう１つの多孔膜が前記正極本体の前記外側面に形成されてもよい。 In one preferable embodiment of the present invention, the porous film is a separator formed of the insulating ceramic on the surface of the positive electrode body on the negative electrode side. In this case, it is preferable that the thickness of the positive electrode main body is larger than the thickness of the separator. Further, another porous film as a positive electrode catalyst layer is formed of ceramic on a surface of the positive electrode body opposite to the negative electrode, and the porous film is formed on the inner surface of the positive electrode body, One porous film may be formed on the outer surface of the positive electrode body.
　本発明の他の好ましい形態では、前記多孔膜が、前記正極本体の前記負極とは反対側の面に形成された正極触媒層である。 In another preferred embodiment of the present invention, the porous membrane is a positive electrode catalyst layer formed on a surface of the positive electrode body opposite to the negative electrode.
　前記正極触媒層を備える金属空気電池では、前記正極触媒層の前記セラミックが前記正極本体の前記導電性セラミックと同じ結晶構造を有してもよい。好ましくは、前記正極触媒層の前記セラミックが、前記正極本体の前記導電性セラミックよりも酸素還元反応に優れ、前記正極本体の前記導電性セラミックが、前記正極触媒層の前記セラミックよりも酸素発生反応に優れる。 In the metal-air battery including the positive electrode catalyst layer, the ceramic of the positive electrode catalyst layer may have the same crystal structure as that of the conductive ceramic of the positive electrode body. Preferably, the ceramic of the positive electrode catalyst layer is superior in oxygen reduction reaction than the conductive ceramic of the positive electrode body, and the conductive ceramic of the positive electrode body is more oxygen generating than the ceramic of the positive electrode catalyst layer. Excellent.
　一の局面では、前記正極本体の前記導電性セラミックの平均粒径が、０．１マイクロメートル以上かつ２マイクロメートル以下である。他の局面では、前記正極触媒層の前記セラミックの平均粒径が、１マイクロメートル以上かつ１０マイクロメートル以下である。好ましくは、前記正極触媒層の厚さが、前記正極本体の厚さの０．４倍以上かつ２．３倍以下である。 In one aspect, an average particle diameter of the conductive ceramic of the positive electrode body is 0.1 micrometer or more and 2 micrometers or less. In another aspect, the average particle size of the ceramic of the positive electrode catalyst layer is not less than 1 micrometer and not more than 10 micrometers. Preferably, the thickness of the positive electrode catalyst layer is not less than 0.4 times and not more than 2.3 times the thickness of the positive electrode body.
　上述の目的および他の目的、特徴、態様および利点は、添付した図面を参照して以下に行うこの発明の詳細な説明により明らかにされる。 The above object and other objects, features, aspects, and advantages will become apparent from the following detailed description of the present invention with reference to the accompanying drawings.
金属空気電池の構成を示す図である。It is a figure which shows the structure of a metal air battery. 正極を作製する流れを示す図である。It is a figure which shows the flow which produces a positive electrode. 比較例の金属空気電池の構成を示す図である。It is a figure which shows the structure of the metal air battery of a comparative example. 金属空気電池の充放電特性を示す図である。It is a figure which shows the charging / discharging characteristic of a metal air battery. 金属空気電池の出力密度を示す図である。It is a figure which shows the output density of a metal air battery. 正極の各層の材料および粒径と充放電性能との関係を示す図である。It is a figure which shows the relationship between the material and particle size of each layer of a positive electrode, and charging / discharging performance.
　図１は、本発明の一の実施の形態に係る金属空気電池１の構成を示す図である。図１の金属空気電池１は亜鉛イオンを利用する二次電池であり、亜鉛空気二次電池である。金属空気電池は、他の金属イオンを利用してもよい。金属空気電池１の本体１１は中心軸Ｊ１を中心とする略円柱状であり、図１では、中心軸Ｊ１に垂直な面における本体１１の断面（後述の負極３を除く。）を示す。金属空気電池１は、正極２、負極３および電解質層４を備える。 FIG. 1 is a diagram showing a configuration of a metal-air battery 1 according to an embodiment of the present invention. The metal-air battery 1 in FIG. 1 is a secondary battery that uses zinc ions, and is a zinc-air secondary battery. The metal-air battery may utilize other metal ions. The main body 11 of the metal-air battery 1 has a substantially cylindrical shape with the central axis J1 as the center. FIG. 1 shows a cross section of the main body 11 in a plane perpendicular to the central axis J1 (excluding the negative electrode 3 described later). The metal-air battery 1 includes a positive electrode 2, a negative electrode 3, and an electrolyte layer 4.
　負極３（金属極とも呼ばれる。）は、中心軸Ｊ１を中心とするコイル状の部材である。本実施の形態における負極３は、断面が略円形の線状の部材を中心軸Ｊ１を中心として螺旋状に巻いた形状を有する。負極３は、導電性材料にて形成されるコイル状の基材、および、基材の表面に形成される析出金属層を備える。中心軸Ｊ１方向における負極３の端部には負極集電端子（図示省略）が接続される。 The negative electrode 3 (also referred to as a metal electrode) is a coiled member centered on the central axis J1. The negative electrode 3 in the present embodiment has a shape in which a linear member having a substantially circular cross section is spirally wound around the central axis J1. The negative electrode 3 includes a coiled base material formed of a conductive material and a deposited metal layer formed on the surface of the base material. A negative electrode current collector terminal (not shown) is connected to the end of the negative electrode 3 in the direction of the central axis J1.
　上記基材を形成する材料として、銅（Ｃｕ）、ニッケル（Ｎｉ）、銀（Ａｇ）、金（Ａｕ）、鉄（Ｆｅ）、アルミニウム（Ａｌ）、マグネシウム（Ｍｇ）等の金属、または、いずれかの金属を含む合金が例示される。本実施の形態では、基材は銅にて形成される。集電体を兼ねる基材の導電率を高くするという観点では、基材は銅または銅合金を含むことが好ましい。基材の本体が銅にて形成される場合、当該本体の表面にニッケル等の他の金属の保護膜が形成されることが好ましい。この場合、基材の表面は、当該保護膜の表面となる。例えば、保護膜の厚さは、１～２０μｍ（マイクロメートル）であり、保護膜は、めっきにて形成される。析出金属層は、亜鉛（Ｚｎ）の電解析出により形成される。析出金属層は、亜鉛を含む合金の電解析出にて形成されてもよい。金属空気電池１の設計によっては、筒状または棒状の負極３が利用されてもよい。 As a material for forming the substrate, a metal such as copper (Cu), nickel (Ni), silver (Ag), gold (Au), iron (Fe), aluminum (Al), magnesium (Mg), or any An alloy containing such a metal is exemplified. In the present embodiment, the base material is formed of copper. From the viewpoint of increasing the conductivity of the base material also serving as a current collector, the base material preferably contains copper or a copper alloy. When the main body of the substrate is formed of copper, it is preferable that a protective film of other metal such as nickel is formed on the surface of the main body. In this case, the surface of the substrate is the surface of the protective film. For example, the thickness of the protective film is 1 to 20 μm (micrometer), and the protective film is formed by plating. The deposited metal layer is formed by electrolytic deposition of zinc (Zn). The deposited metal layer may be formed by electrolytic deposition of an alloy containing zinc. Depending on the design of the metal-air battery 1, a cylindrical or rod-shaped negative electrode 3 may be used.
　負極３の周囲には、円筒状のセパレータ４１が設けられ、セパレータ４１の周囲には、円筒状の正極２（空気極とも呼ばれる。）が設けられる。すなわち、セパレータ４１の内側面は負極３に対向し、セパレータ４１の外側面は正極２の内側面に対向する。負極３、セパレータ４１および正極２は、中心軸Ｊ１を中心とする同心状に設けられ、中心軸Ｊ１に沿って見た場合に、負極３の外縁と正極２との間の距離は、中心軸Ｊ１を中心とする周方向の全周に亘って一定である。すなわち、金属空気電池１における負極３および正極２の間では、全周に亘って、等電位面の間隔が一定である。等電位面に粗密がないため、充放電時の電流分布は周方向において一定となる。なお、全周に亘る電流分布がおよそ均一となるのであるならば、正極２の形状は、例えば、頂点が６個以上の正多角形の筒状であってもよい。セパレータ４１の詳細については後述する。 A cylindrical separator 41 is provided around the negative electrode 3, and a cylindrical positive electrode 2 (also referred to as an air electrode) is provided around the separator 41. That is, the inner surface of the separator 41 faces the negative electrode 3, and the outer surface of the separator 41 faces the inner surface of the positive electrode 2. The negative electrode 3, the separator 41, and the positive electrode 2 are provided concentrically with the central axis J1 as the center, and when viewed along the central axis J1, the distance between the outer edge of the negative electrode 3 and the positive electrode 2 is the central axis. It is constant over the entire circumference in the circumferential direction centered on J1. That is, between the negative electrode 3 and the positive electrode 2 in the metal-air battery 1, the equipotential surface interval is constant over the entire circumference. Since the equipotential surface is not dense, the current distribution during charging and discharging is constant in the circumferential direction. If the current distribution over the entire circumference is approximately uniform, the shape of the positive electrode 2 may be, for example, a regular polygonal cylinder having six or more vertices. Details of the separator 41 will be described later.
　正極２は、導電性セラミックにて形成された筒状の支持体である多孔質の正極本体２１、および、正極本体２１の負極３とは反対側の外側面に形成された正極触媒層２２を有する。好ましくは、正極触媒層２２は、正極本体２１の全周に亘って形成される。正極触媒層２２の外側面の一部には、耐アルカリ性を有するセラミックにて形成されるインターコネクタ２４が設けられる。インターコネクタ２４の厚さは、例えば約３０～３００μｍである。インターコネクタ２４には正極集電端子（図示省略）が接続される。正極触媒層２２の外側面において、インターコネクタ２４にて覆われていない領域には、撥水性を有する材料（例えば、ＦＥＰ（テトラフルオロエチレン・ヘキサフルオロプロピレン共重合体）やＰＴＦＥ（ポリテトラフルオロエチレン））による多孔質の層が撥液層２９として形成される。撥液層２９は、高いガス透過性および高い液不透過性を有する。 The positive electrode 2 includes a porous positive electrode main body 21 that is a cylindrical support formed of a conductive ceramic, and a positive electrode catalyst layer 22 formed on the outer surface of the positive electrode main body 21 opposite to the negative electrode 3. Have. Preferably, the positive electrode catalyst layer 22 is formed over the entire circumference of the positive electrode main body 21. An interconnector 24 made of ceramic having alkali resistance is provided on a part of the outer surface of the positive electrode catalyst layer 22. The thickness of the interconnector 24 is, for example, about 30 to 300 μm. A positive current collector terminal (not shown) is connected to the interconnector 24. On the outer surface of the positive electrode catalyst layer 22, a region not covered with the interconnector 24 has a water-repellent material (for example, FEP (tetrafluoroethylene / hexafluoropropylene copolymer) or PTFE (polytetrafluoroethylene). )) Is formed as the liquid repellent layer 29. The liquid repellent layer 29 has high gas permeability and high liquid impermeability.
　正極導電層である正極本体２１は、導電性セラミックを含む材料の押出成形および焼成により形成される。導電性セラミックとして、好ましくは、導電性を有するペロブスカイト型酸化物またはスピネル型酸化物が利用される。本実施の形態では、正極本体２１は、ペロブスカイト型酸化物（例えば、ＬＳＭ（ＬａＳｒＭｎＯ３）、ＬＳＭＦ（ＬａＳｒＭｎＦｅＯ３）、あるいは、ＬＳＣＦ（ＬａＳｒＣｏＦｅＯ３））にて形成される。正極本体２１において利用されるペロブスカイト型酸化物は、Ｃｏ、Ｍｎ、Ｆｅのうちの少なくとも１種を含むことが好ましい。充電時における酸化による劣化を防止するという観点では、正極本体２１は、導電性カーボンを含まないことが好ましい。正極本体２１は、他の導電性セラミックにより形成されてよい。正極本体２１のガス透過量は、２０００ｍ３／（ｍ２・ｈ・ａｔｍ）以上であることが好ましく、この場合、正極本体２１の空孔率は、３０％以上であることが好ましい。空孔率が３０％よりも小さい場合、ガス透過性が過度に低くなる。また、正極本体２１の空孔率は、８０％以下であることが好ましい。空孔率が８０％よりも大きい場合、正極本体２１の支持体としての強度が低下する。 The positive electrode main body 21 which is a positive electrode conductive layer is formed by extrusion molding and firing of a material containing a conductive ceramic. As the conductive ceramic, a perovskite oxide or spinel oxide having conductivity is preferably used. In the present embodiment, the positive electrode body 21 is made of a perovskite oxide (for example, LSM (LaSrMnO 3 ), LSMF (LaSrMnFeO 3 ), or LSCF (LaSrCoFeO 3 )). The perovskite oxide used in the positive electrode body 21 preferably contains at least one of Co, Mn, and Fe. From the viewpoint of preventing deterioration due to oxidation during charging, the positive electrode body 21 preferably does not contain conductive carbon. The positive electrode main body 21 may be formed of other conductive ceramics. The gas permeation amount of the positive electrode main body 21 is preferably 2000 m 3 / (m 2 · h · atm) or more. In this case, the porosity of the positive electrode main body 21 is preferably 30% or more. When the porosity is smaller than 30%, the gas permeability is excessively lowered. Further, the porosity of the positive electrode main body 21 is preferably 80% or less. When the porosity is larger than 80%, the strength of the positive electrode body 21 as a support is lowered.
　また、正極触媒層２２は、ペロブスカイト型酸化物（例えば、ＬＳＭ、ＬＳＣＦ、あるいは、ＬＳＭＦ）等の導電性セラミックの粉体を、例えばスラリーコート法および焼成により、正極本体２１上に担持させた部位を含む。正極触媒層２２は、正極本体２１の負極３とは反対側の外側面上にセラミックにて形成された多孔膜であり、支持体である正極本体２１により支持される。例えば、正極触媒層２２の厚さは、正極本体２１の厚さよりも十分に小さい。金属空気電池１では、原則として、多孔質の正極触媒層２２近傍において空気と後述の電解液４０との界面が形成される。 The positive electrode catalyst layer 22 is a portion in which a conductive ceramic powder such as a perovskite oxide (for example, LSM, LSCF, or LSMF) is supported on the positive electrode body 21 by, for example, a slurry coating method and firing. including. The positive electrode catalyst layer 22 is a porous film formed of ceramic on the outer surface of the positive electrode main body 21 opposite to the negative electrode 3 and is supported by the positive electrode main body 21 as a support. For example, the thickness of the positive electrode catalyst layer 22 is sufficiently smaller than the thickness of the positive electrode main body 21. In the metal-air battery 1, in principle, an interface between air and an electrolyte solution 40 described later is formed in the vicinity of the porous positive electrode catalyst layer 22.
　既述のセパレータ４１は、正極本体２１の負極３側の内側面に形成される多孔膜であり、当該内側面の全周に亘って形成される。セパレータ４１は、例えば、シリカ（ＳｉＯ２）、アルミナ（Ａｌ２Ｏ３）、ジルコニア（ＺｒＯ２）、チタニア（ＴｉＯ２）、ハフニア（ＨｆＯ２）およびセリア（ＣｅＯ２）等の機械的強度および絶縁性が高いセラミック粉末の焼結体であり、耐アルカリ性を有する。後述するように、セパレータ４１の作製では、正極本体２１の内側面にスラリーコート法等により上記セラミック粉末およびバインダを含むスラリーを成膜して乾燥し、高温の焼成によりスラリーに含まれるバインダが除去される。これにより、バインダの劣化によりセパレータの寿命が短くなることが防止される。セパレータ４１は、セラミックのみにて構成されることが好ましい。セパレータ４１は、これらのセラミックの混合体や積層体であってもよい。 The separator 41 described above is a porous film formed on the inner surface of the positive electrode body 21 on the negative electrode 3 side, and is formed over the entire circumference of the inner surface. The separator 41 is, for example, mechanical strength and insulation such as silica (SiO 2 ), alumina (Al 2 O 3 ), zirconia (ZrO 2 ), titania (TiO 2 ), hafnia (HfO 2 ), and ceria (CeO 2 ). It is a sintered body of ceramic powder with high properties and has alkali resistance. As will be described later, in the production of the separator 41, a slurry containing the ceramic powder and the binder is formed on the inner surface of the positive electrode body 21 by a slurry coating method and dried, and the binder contained in the slurry is removed by high-temperature firing. Is done. This prevents the life of the separator from being shortened due to the deterioration of the binder. The separator 41 is preferably composed only of ceramic. The separator 41 may be a mixture or laminate of these ceramics.
　上記セラミック粉末の平均粒子径は、好ましくは、０．１μｍ以上、かつ、３０μｍ以下であり、必要に応じて分級加工により粒子径が揃えられる。セパレータ４１の平均細孔径は０．０１μｍ以上、２μｍ以下であることが好ましい。これにより、負極３の析出金属（デンドライト等）がセパレータ４１を貫通することが防止される。セパレータ４１の平均細孔径は、正極本体２１の平均細孔径よりも小さいことが好ましい。また、円筒状のセパレータ４１の厚さ（肉厚）は５０μｍ以上、２００μｍ以下であり、正極本体２１の厚さよりも小さいことが好ましい。 The average particle size of the ceramic powder is preferably 0.1 μm or more and 30 μm or less, and the particle size is adjusted by classification as necessary. The average pore diameter of the separator 41 is preferably 0.01 μm or more and 2 μm or less. Thereby, the deposited metal (dendrites or the like) of the negative electrode 3 is prevented from penetrating the separator 41. The average pore diameter of the separator 41 is preferably smaller than the average pore diameter of the positive electrode body 21. The thickness (wall thickness) of the cylindrical separator 41 is 50 μm or more and 200 μm or less, and is preferably smaller than the thickness of the positive electrode body 21.
　筒状の正極２の内側（中心軸Ｊ１側）の空間には、水系の電解液４０が充填される。電解液４０は、正極２と負極３との間に介在し、両極に接する。負極３のおよそ全体は電解液４０中に浸漬される。多孔質のセパレータ４１、および、正極本体２１の細孔にも電解液４０が充填される。さらに、正極触媒層２２の一部の細孔にも電解液４０が充填される。以下の説明では、中心軸Ｊ１に沿って見た場合における負極３と正極２との間の空間を「電解質層４」という。すなわち、電解質層４は、負極３と正極２との間に配置される。本実施の形態では、電解質層４はセパレータ４１を含む。 The space inside the cylindrical positive electrode 2 (center axis J1 side) is filled with an aqueous electrolyte 40. The electrolytic solution 40 is interposed between the positive electrode 2 and the negative electrode 3 and is in contact with both electrodes. About the entire negative electrode 3 is immersed in the electrolytic solution 40. The electrolyte 40 is also filled in the porous separator 41 and the pores of the positive electrode main body 21. Further, the electrolyte solution 40 is also filled in some of the pores of the positive electrode catalyst layer 22. In the following description, the space between the negative electrode 3 and the positive electrode 2 when viewed along the central axis J1 is referred to as “electrolyte layer 4”. That is, the electrolyte layer 4 is disposed between the negative electrode 3 and the positive electrode 2. In the present embodiment, the electrolyte layer 4 includes a separator 41.
　電解液４０は、アルカリ水溶液であり、好ましくは、水酸化カリウム（苛性カリ、ＫＯＨ）水溶液、または、水酸化ナトリウム（苛性ソーダ、ＮａＯＨ）水溶液を含む。また、電解液４０は、亜鉛イオンまたは亜鉛を含むイオンを含む。すなわち、電解液４０に含まれる亜鉛イオンは、様々な態様で存在してよく、亜鉛（すなわち、亜鉛原子）を含むイオンと捉えられてもよい。例えば、テトラヒドロキシ亜鉛イオンとして存在してもよい。 The electrolytic solution 40 is an alkaline aqueous solution, and preferably contains a potassium hydroxide (caustic potash, KOH) aqueous solution or a sodium hydroxide (caustic soda, NaOH) aqueous solution. Further, the electrolytic solution 40 includes zinc ions or ions containing zinc. That is, the zinc ions contained in the electrolytic solution 40 may exist in various forms and may be regarded as ions containing zinc (that is, zinc atoms). For example, it may exist as tetrahydroxyzinc ions.
　中心軸Ｊ１方向において負極３、電解質層４および正極２の両端面には、円板状の閉塞部材が固定される。各閉塞部材の中央には貫通孔が設けられる。金属空気電池１では、撥液層２９および閉塞部材により、本体１１内の電解液４０が上記貫通孔以外から外部へと漏出することが防止される。また、両端面上の閉塞部材の貫通孔を利用して、本体１１と図示省略の貯溜タンクとの間にて電解液を循環させることが可能である。 Disc-shaped blocking members are fixed to both end faces of the negative electrode 3, the electrolyte layer 4, and the positive electrode 2 in the direction of the central axis J1. A through hole is provided in the center of each closing member. In the metal-air battery 1, the liquid repellent layer 29 and the closing member prevent the electrolytic solution 40 in the main body 11 from leaking outside the through hole. Moreover, it is possible to circulate electrolyte solution between the main body 11 and the storage tank not shown using the through-hole of the obstruction | occlusion member on both end surfaces.
　図１の金属空気電池１において放電が行われる際には、負極集電端子と正極集電端子とが、例えば、照明器具等の負荷を介して電気的に接続される。負極３が有する亜鉛は酸化されて亜鉛イオンが生成され、電子は負極集電端子、および、正極集電端子を介して正極２に供給される。多孔質の正極２では、撥液層２９を透過した空気中の酸素が、負極３から供給された電子により還元され、水酸化物イオンとして電解液中に溶出する。正極２では、正極触媒により酸素の還元反応が促進される。 When the discharge is performed in the metal-air battery 1 of FIG. 1, the negative electrode current collector terminal and the positive electrode current collector terminal are electrically connected via a load such as a lighting fixture, for example. Zinc included in the negative electrode 3 is oxidized to generate zinc ions, and electrons are supplied to the positive electrode 2 via the negative electrode current collector terminal and the positive electrode current collector terminal. In the porous positive electrode 2, oxygen in the air that has passed through the liquid repellent layer 29 is reduced by the electrons supplied from the negative electrode 3 and is eluted into the electrolyte as hydroxide ions. In the positive electrode 2, the reduction reaction of oxygen is promoted by the positive electrode catalyst.
　一方、金属空気電池１において充電が行われる際には、負極集電端子と正極集電端子との間に電圧が付与され、正極２に対して水酸化物イオンから電子が供給されるとともに酸素が発生する。負極３では、正極集電端子を介して負極集電端子に供給される電子により金属イオンが還元されて亜鉛が析出する。 On the other hand, when the metal-air battery 1 is charged, a voltage is applied between the negative electrode current collector terminal and the positive electrode current collector terminal, and electrons are supplied from the hydroxide ions to the positive electrode 2 and oxygen is added. Occurs. In the negative electrode 3, the metal ions are reduced by the electrons supplied to the negative electrode current collector terminal via the positive electrode current collector terminal, and zinc is deposited.
　このとき、コイル状の負極３では、角部がないため、電界集中が起こりにくい。すなわち、電流密度に大きな偏りが生じない。また、負極３が、電解液４０に均一に接触する。その結果、亜鉛が樹枝状に析出するデンドライトや、ひげ状（針状）に析出するウィスカーの生成および成長が大きく抑制される。実際には、負極３の表面のほぼ全体において緻密な亜鉛が均一に析出し、析出金属層が形成される。正極２では、正極触媒層２２に含まれる正極触媒により酸素の発生が促進される。さらに、正極２では、カーボン素材を用いていないことにより、充電時に発生する酸素による酸化劣化が生じることはない。 At this time, the coiled negative electrode 3 has no corners, so that electric field concentration hardly occurs. That is, there is no significant bias in current density. Further, the negative electrode 3 is in uniform contact with the electrolytic solution 40. As a result, the generation and growth of dendrites in which zinc precipitates in a dendritic shape and whiskers in which the zinc precipitates in a whisker shape (needle shape) are greatly suppressed. Actually, dense zinc is uniformly deposited on almost the entire surface of the negative electrode 3 to form a deposited metal layer. In the positive electrode 2, the generation of oxygen is promoted by the positive electrode catalyst contained in the positive electrode catalyst layer 22. Furthermore, since the positive electrode 2 does not use a carbon material, oxidative deterioration due to oxygen generated during charging does not occur.
　上述のように、金属空気電池１では、正極本体２１を支持体として、正極本体２１の外側面に正極触媒層２２が形成され、正極本体２１の内側面にセパレータ４１が形成される。すなわち、セパレータ４１および正極２が一繋がりの部材として作製される。図２は、セパレータ４１が設けられた正極２を作製する流れを示す図である。図２は、正極２の作製の基本的な流れを示すものであり、処理順序は適宜変更されてよい。 As described above, in the metal-air battery 1, the positive electrode main body 21 is used as a support, the positive electrode catalyst layer 22 is formed on the outer surface of the positive electrode main body 21, and the separator 41 is formed on the inner surface of the positive electrode main body 21. That is, the separator 41 and the positive electrode 2 are produced as a continuous member. FIG. 2 is a diagram showing a flow of manufacturing the positive electrode 2 provided with the separator 41. FIG. 2 shows a basic flow of manufacturing the positive electrode 2, and the processing order may be changed as appropriate.
　正極２の作製では、まず、導電性セラミックを含む正極形成材料の押出成形および焼成により円筒状の正極本体２１が多孔質の支持体として形成される（ステップＳ１１）。導電性セラミックとして、例えば、ペロブスカイト型酸化物が利用され、ここでは、ＬＳＭまたはＬＳＣＦが利用される。正極導電層である正極本体２１において高い導電性を確保し、かつ、酸素発生反応触媒としての機能も確保するという観点では、ＬＳＣＦを利用することが好ましい。 In the production of the positive electrode 2, first, the cylindrical positive electrode main body 21 is formed as a porous support by extrusion molding and baking of a positive electrode forming material containing a conductive ceramic (step S11). As the conductive ceramic, for example, a perovskite oxide is used, and here, LSM or LSCF is used. From the viewpoint of ensuring high conductivity in the positive electrode main body 21 which is the positive electrode conductive layer and also ensuring the function as an oxygen generation reaction catalyst, it is preferable to use LSCF.
　焼成の前に、成形体を１００～８００℃で加熱処理して成形体中の有機成分を分解除去してもよい。焼成は、成形体が十分に焼結し、かつ、ガス透過性や電解液浸透性、電池性能を保持できる条件であればよく、９００～１５００℃で行われることが好ましい。また、成形体を後述の他の層と共焼成してもよい。共焼成を行うことにより、成形体と当該層との間の接着強度を向上させることができる。また、各層を個別に焼成する場合に比べて、焼成工程のリードタイムを低減することができる。正極本体２１は、押出成形および焼成以外の手法にて形成されてよい。 Prior to firing, the molded body may be heat-treated at 100 to 800 ° C. to decompose and remove organic components in the molded body. The firing may be performed under conditions that allow the molded body to be sufficiently sintered and maintain gas permeability, electrolyte solution permeability, and battery performance, and is preferably performed at 900 to 1500 ° C. Moreover, you may co-fire a molded object with the other layer mentioned later. By performing co-firing, the adhesive strength between the molded body and the layer can be improved. Moreover, the lead time of a baking process can be reduced compared with the case where each layer is baked separately. The positive electrode main body 21 may be formed by a technique other than extrusion molding and baking.
　正極本体２１が準備されると、正極本体２１の外側面にスラリーコート法により正極触媒を含むスラリーを成膜し、正極本体２１と共に焼成することにより、正極触媒層２２が形成される（ステップＳ１２）。正極触媒として、例えば、ペロブスカイト型酸化物等のセラミックが利用され、ここでは、ＬＳＭ、ＬＳＣＦまたはＬＳＭＦが利用される。このとき、正極触媒層２２のセラミックが、正極本体２１を形成する導電性セラミックと同じ結晶構造を有することにより、正極本体２１と正極触媒層２２との熱膨張係数差が小さくなり、焼成によるクラックや剥離の発生が抑制される。 When the positive electrode main body 21 is prepared, a slurry containing a positive electrode catalyst is formed on the outer surface of the positive electrode main body 21 by a slurry coating method, and baked together with the positive electrode main body 21, thereby forming the positive electrode catalyst layer 22 (step S12). ). As the positive electrode catalyst, for example, a ceramic such as a perovskite oxide is used. Here, LSM, LSCF, or LSMF is used. At this time, since the ceramic of the positive electrode catalyst layer 22 has the same crystal structure as the conductive ceramic forming the positive electrode main body 21, the difference in thermal expansion coefficient between the positive electrode main body 21 and the positive electrode catalyst layer 22 is reduced, and cracks due to firing And the occurrence of peeling are suppressed.
　スラリーの膜の形成（成膜）は、キャスティング法、ディッピング法、スプレー法、印刷法等の様々な手法が利用可能である。正極２における各層の膜厚は、ガス透過性、電解液浸透性等、電池性能に関わる特性を保持させるという観点と、焼成時の焼成収縮を考慮して、適宜調整される。正極触媒層２２は、上記成膜および焼成以外の手法にて形成されてよい（インターコネクタ２４、セパレータ４１および撥液層２９において同様）。 Various methods such as a casting method, a dipping method, a spray method, and a printing method can be used for forming a slurry film (film formation). The film thickness of each layer in the positive electrode 2 is appropriately adjusted in consideration of maintaining characteristics related to battery performance such as gas permeability and electrolyte solution permeability, and firing shrinkage during firing. The positive electrode catalyst layer 22 may be formed by a method other than the above film formation and baking (the same applies to the interconnector 24, the separator 41, and the liquid repellent layer 29).
　正極触媒層２２が形成されると、正極触媒層２２の外側面に対して、一部の領域を除いてマスキングが行われる。続いて、ペロブスカイト型酸化物等の微細な粉末を含むスラリーを用いて、スラリーコート法により当該領域に対して膜が形成され、当該膜を正極本体２１および正極触媒層２２と共に焼成することにより、インターコネクタ２４が形成される（ステップＳ１３）。 When the positive electrode catalyst layer 22 is formed, masking is performed on the outer surface of the positive electrode catalyst layer 22 except for a part of the region. Subsequently, using a slurry containing fine powder such as a perovskite oxide, a film is formed on the region by a slurry coating method, and the film is baked together with the positive electrode body 21 and the positive electrode catalyst layer 22, The interconnector 24 is formed (step S13).
　インターコネクタ２４が形成されると、正極本体２１の内側面にスラリーコート法によりセパレータ形成材料を含むスラリーを成膜し、正極本体２１、正極触媒層２２およびインターコネクタ２４と共に焼成することにより、セパレータ４１が形成される（ステップＳ１４）。セパレータ形成材料として、例えば、絶縁性のセラミックが利用され、ここでは、アルミナまたはジルコニアが利用される。セパレータ４１の焼成では、スラリーに含まれるバインダが除去されることが好ましい。 When the interconnector 24 is formed, a slurry containing a separator forming material is formed on the inner surface of the positive electrode body 21 by a slurry coating method, and fired together with the positive electrode body 21, the positive electrode catalyst layer 22, and the interconnector 24. 41 is formed (step S14). As the separator forming material, for example, an insulating ceramic is used, and here, alumina or zirconia is used. In firing the separator 41, it is preferable that the binder contained in the slurry is removed.
　セパレータ４１が形成されると、正極触媒層２２の外側面にスラリーコート法により撥液材料を含むスラリーを成膜し、正極本体２１、正極触媒層２２、インターコネクタ２４およびセパレータ４１と共に焼成することにより、撥液層２９が形成される（ステップＳ１５）。撥液材料を含むスラリーの成膜では、インターコネクタ２４の部分をマスキングすることが好ましい。撥液材料として、例えば、ＦＥＰやＰＴＦＥが利用される。また、スラリーに増粘剤を必要量添加してスラリー粘度を調整することにより、正極触媒層２２の深度方向への染み込み深さが調整される。これにより、正極触媒層２２における細孔内の粒子表面が撥液材料により完全に覆われることを防止しつつ、金属空気電池１において、正極触媒層２２の近傍に三相界面を形成することが実現される。 When the separator 41 is formed, a slurry containing a liquid repellent material is formed on the outer surface of the positive electrode catalyst layer 22 by a slurry coating method, and fired together with the positive electrode main body 21, the positive electrode catalyst layer 22, the interconnector 24, and the separator 41. Thus, the liquid repellent layer 29 is formed (step S15). In forming a slurry containing a liquid repellent material, it is preferable to mask the portion of the interconnector 24. As the liquid repellent material, for example, FEP or PTFE is used. Moreover, the penetration depth to the depth direction of the positive electrode catalyst layer 22 is adjusted by adjusting a slurry viscosity by adding a required amount of thickeners to a slurry. Thereby, the three-phase interface can be formed in the vicinity of the positive electrode catalyst layer 22 in the metal-air battery 1 while preventing the particle surfaces in the pores of the positive electrode catalyst layer 22 from being completely covered with the liquid repellent material. Realized.
　ここで、セパレータを支持体とする比較例の金属空気電池を想定する。図３は、比較例の金属空気電池９の構成を示す図であり、図１に対応する断面図である。比較例の金属空気電池９では、アルミナにて形成されるセパレータ９４が筒状の支持体であり、セパレータ９４の外側面に正極９２の正極導電層９２１等が設けられる。正極９２はペロブスカイト型酸化物を含むスラリーのスラリーコート法による成膜および焼成を、複数回繰り返すことにより所定の厚さにて形成される。 Here, a metal-air battery of a comparative example using a separator as a support is assumed. FIG. 3 is a diagram showing a configuration of the metal-air battery 9 of the comparative example, and is a cross-sectional view corresponding to FIG. In the metal-air battery 9 of the comparative example, the separator 94 formed of alumina is a cylindrical support, and the positive electrode conductive layer 921 of the positive electrode 92 and the like are provided on the outer surface of the separator 94. The positive electrode 92 is formed to have a predetermined thickness by repeating film formation and firing of a slurry containing a perovskite oxide by a slurry coating method a plurality of times.
　比較例の金属空気電池９では、正極９２を厚くするには、成膜および焼成を多数回繰り返す必要があるため、金属空気電池９（の正極９２）の製造が煩雑となる。また、正極９２のクラックや剥離も生じ易くなる。実際には、正極９２の厚膜化には、製造コスト等との兼ね合いから一定の限界が生じる。したがって、比較例の金属空気電池９では、正極９２の厚さが比較的薄くなる。その結果、正極９２の電気抵抗が高くなり、電池性能の向上が困難となる。 In the metal-air battery 9 of the comparative example, in order to increase the thickness of the positive electrode 92, it is necessary to repeat film formation and firing many times, so that the manufacture of the metal-air battery 9 (the positive electrode 92) becomes complicated. Further, cracks and peeling of the positive electrode 92 are likely to occur. Actually, there is a certain limit in increasing the thickness of the positive electrode 92 in consideration of the manufacturing cost and the like. Therefore, in the metal-air battery 9 of the comparative example, the thickness of the positive electrode 92 is relatively thin. As a result, the electrical resistance of the positive electrode 92 is increased, and it is difficult to improve battery performance.
　これに対し、図１の金属空気電池１では、正極２が、導電性セラミックにて形成された筒状の支持体である多孔質の正極本体２１を備え、正極本体２１の内側面に絶縁性のセラミックにて形成された多孔膜であるセパレータ４１が設けられる。このように、正極本体２１を支持体とすることにより、正極２を容易に厚くすることができ、正極２の電気抵抗を低くして、金属空気電池１の電池性能を向上することができる。また、セパレータを支持体とする比較例のように、スラリーコートおよび焼成を繰り返して、正極２を厚膜化する必要が無いため、金属空気電池１の製造工程を減らす（簡略化する）ことができる。さらに、セパレータ４１が支持体ではない金属空気電池１では、セパレータ９４を支持体とする比較例の金属空気電池９に比べて、セパレータ４１を大幅に薄くすることができる。その結果、負極３と正極２との間の距離を小さくして、金属空気電池１の電池性能をさらに向上することができる。また、セパレータ４１の形成におけるクラックや剥離の発生も抑制することができる。 In contrast, in the metal-air battery 1 of FIG. 1, the positive electrode 2 includes a porous positive electrode body 21 that is a cylindrical support formed of a conductive ceramic, and an insulating surface is provided on the inner surface of the positive electrode body 21. A separator 41, which is a porous film made of ceramic, is provided. Thus, by using the positive electrode main body 21 as a support, the positive electrode 2 can be easily thickened, the electric resistance of the positive electrode 2 can be lowered, and the battery performance of the metal-air battery 1 can be improved. Further, unlike the comparative example using the separator as a support, it is not necessary to repeat the slurry coating and firing to increase the thickness of the positive electrode 2, thereby reducing (simplifying) the manufacturing process of the metal-air battery 1. it can. Further, in the metal-air battery 1 in which the separator 41 is not a support, the separator 41 can be made much thinner than the metal-air battery 9 of the comparative example using the separator 94 as a support. As a result, the distance between the negative electrode 3 and the positive electrode 2 can be reduced, and the battery performance of the metal-air battery 1 can be further improved. Moreover, generation | occurrence | production of the crack in the formation of the separator 41 and peeling can also be suppressed.
　図１の金属空気電池１では、正極本体２１の厚さが、セパレータ４１の厚さよりも大きいことにより、正極２の電気抵抗を低くしつつ、負極３と正極２との間の距離を小さくすることができ、金属空気電池１の電池性能をさらに向上することができる。正極本体２１の厚さは、好ましくは、セパレータ４１の厚さの３倍よりも大きく、より好ましくは、５倍よりも大きい。 In the metal-air battery 1 of FIG. 1, since the thickness of the positive electrode main body 21 is larger than the thickness of the separator 41, the distance between the negative electrode 3 and the positive electrode 2 is reduced while reducing the electrical resistance of the positive electrode 2. The battery performance of the metal-air battery 1 can be further improved. The thickness of the positive electrode main body 21 is preferably larger than 3 times the thickness of the separator 41, more preferably larger than 5 times.
　既述のように、金属空気電池１では、正極触媒層２２において電解液と空気の界面が形成される。金属空気電池１における放電では、空気中の酸素、および、電解液中の水から水酸化物イオンが生成される酸素還元反応が、正極触媒層２２において主に生じる。したがって、正極触媒層２２は、放電反応層として捉えることができ、正極触媒層２２は、正極本体２１を形成する導電性セラミックよりも、酸素還元反応に優れたセラミックにて形成されることが好ましい。正極本体２１および正極触媒層２２のうち、酸素還元反応の活物質である酸素と接する正極触媒層２２に、酸素還元反応用の触媒を用いることにより、当該活物質が当該触媒に効率よく供給される。これにより、濃度過電圧を低減して、金属空気電池１における放電性能を向上することができる。 As described above, in the metal-air battery 1, an interface between the electrolytic solution and air is formed in the positive electrode catalyst layer 22. In the discharge in the metal-air battery 1, an oxygen reduction reaction in which hydroxide ions are generated from oxygen in the air and water in the electrolyte mainly occurs in the positive electrode catalyst layer 22. Therefore, the positive electrode catalyst layer 22 can be regarded as a discharge reaction layer, and the positive electrode catalyst layer 22 is preferably formed of a ceramic superior in oxygen reduction reaction than the conductive ceramic forming the positive electrode body 21. . Of the positive electrode main body 21 and the positive electrode catalyst layer 22, the active material is efficiently supplied to the catalyst by using a catalyst for the oxygen reduction reaction for the positive electrode catalyst layer 22 in contact with oxygen which is an active material for the oxygen reduction reaction. The Thereby, concentration overvoltage can be reduced and the discharge performance in the metal-air battery 1 can be improved.
　一方、金属空気電池１における充電では、電解液中の水酸化物イオンから酸素および水が生成される酸素発生反応が、正極導電層である正極本体２１において主に生じる。したがって、正極本体２１は、充電反応層として捉えることができ、正極本体２１は、正極触媒層２２を形成するセラミックよりも、酸素発生反応に優れた導電性セラミックにて形成されることが好ましい。正極本体２１および正極触媒層２２のうち、酸素発生反応の活物質である水酸化物イオン（を含む電解液）が充填される正極本体２１に、酸素発生反応用の触媒を用いることにより、当該活物質が当該触媒に効率よく供給される。これにより、濃度過電圧を低減して、金属空気電池１における充電性能を向上することができる。 On the other hand, in the charging in the metal-air battery 1, an oxygen generation reaction in which oxygen and water are generated from hydroxide ions in the electrolyte mainly occurs in the positive electrode body 21 that is the positive electrode conductive layer. Therefore, the positive electrode main body 21 can be regarded as a charge reaction layer, and the positive electrode main body 21 is preferably formed of a conductive ceramic superior in oxygen generation reaction than the ceramic forming the positive electrode catalyst layer 22. By using a catalyst for oxygen generation reaction in the positive electrode main body 21 filled with hydroxide ions (including an electrolyte) that is an active material for oxygen generation reaction among the positive electrode main body 21 and the positive electrode catalyst layer 22, The active material is efficiently supplied to the catalyst. Thereby, concentration overvoltage can be reduced and the charging performance in the metal-air battery 1 can be improved.
　ここで、酸素還元反応および酸素発生反応の優劣の評価は、例えば、特開２００５－１９０８３３号公報（文献３）に記載の手法により行うことが可能である。すなわち、各種材料を触媒として用いたガス拡散型電極を形成し、酸素還元反応および酸素発生反応を生じさせ、所定の電極電流密度を示す参照極に対する電圧が測定される。酸素還元反応では、当該電圧が大きい材料ほど酸素還元反応が優れているといえ、酸素発生反応では、当該電圧が小さい材料ほど酸素発生反応が優れているといえる。 Here, the superiority or inferiority of the oxygen reduction reaction and the oxygen generation reaction can be evaluated, for example, by the technique described in JP-A-2005-190833 (Document 3). That is, a gas diffusion electrode using various materials as a catalyst is formed, an oxygen reduction reaction and an oxygen generation reaction are caused, and a voltage with respect to a reference electrode showing a predetermined electrode current density is measured. In the oxygen reduction reaction, it can be said that the material with a higher voltage has a better oxygen reduction reaction, and in the oxygen generation reaction, the material with a lower voltage has a better oxygen generation reaction.
　正極触媒層２２および正極本体２１の好ましい材料は、ペロブスカイト型酸化物である。ペロブスカイト型酸化物は、Ａをアルカリ金属、アルカリ土類金属、または、希土類金属とし、Ｂを遷移金属として、ＡＢＯ３で表される。正極触媒層２２の好ましい材料は、ペロブスカイト型酸化物において、ＡサイトがＬａ、Ｓｒ、Ｃａの少なくとも一種から構成され、ＢサイトがＦｅ、Ｎｉ、Ｃｏ、Ｍｎの少なくとも一種から構成される。正極本体２１の好ましい材料は、ペロブスカイト型酸化物において、ＡサイトがＬａ、Ｓｒの少なくとも一種から構成され、ＢサイトがＣｏ、Ｆｅの少なくとも一種から構成される（ただし、正極触媒層２２の材料と相違することが好ましい。）。例えば、放電反応層である正極触媒層２２をＬＳＭまたはＬＳＭＦにて形成し、充電反応層である正極本体２１をＬＳＣＦにて形成する場合、正極触媒層２２のセラミックが正極本体２１のセラミックよりも酸素還元反応に優れ、かつ、正極本体２１のセラミックが正極触媒層２２のセラミックよりも酸素発生反応に優れる。 A preferred material for the positive electrode catalyst layer 22 and the positive electrode body 21 is a perovskite oxide. The perovskite oxide is represented by ABO 3 where A is an alkali metal, alkaline earth metal, or rare earth metal, and B is a transition metal. A preferred material for the positive electrode catalyst layer 22 is a perovskite oxide, wherein the A site is composed of at least one of La, Sr, and Ca, and the B site is composed of at least one of Fe, Ni, Co, and Mn. A preferable material for the positive electrode body 21 is a perovskite oxide, in which the A site is composed of at least one of La and Sr, and the B site is composed of at least one of Co and Fe. Preferably different). For example, when the positive electrode catalyst layer 22 that is a discharge reaction layer is formed of LSM or LSMF and the positive electrode body 21 that is a charge reaction layer is formed of LSCF, the ceramic of the positive electrode catalyst layer 22 is more than the ceramic of the positive electrode body 21. The oxygen reduction reaction is excellent, and the ceramic of the positive electrode main body 21 is superior in the oxygen generation reaction than the ceramic of the positive electrode catalyst layer 22.
　正極触媒層２２を構成するセラミックの粒子の平均粒径は、放電反応における一定のガス拡散性を確保するには、１μｍ以上であることが好ましく、ある程度の反応面積を確保するには、１０μｍ以下であることが好ましい。これにより、金属空気電池における放電性能をさらに向上することができる。また、正極本体２１を構成する導電性セラミックの粒子の平均粒径は、電解液を十分に保持するためのサイズの空孔を確保するには、０．１μｍ以上であることが好ましく、充電反応におけるある程度の反応面積を確保するには、２μｍ以下であることが好ましい。これにより、金属空気電池における充電性能をさらに向上することができる。セラミック粒子の平均粒径は、例えば、正極２の断面を研磨して得られる平滑面の走査型電子顕微鏡による画像において、インターセプト法を用いて求められる。 The average particle diameter of the ceramic particles constituting the positive electrode catalyst layer 22 is preferably 1 μm or more in order to ensure a certain gas diffusibility in the discharge reaction, and 10 μm or less in order to ensure a certain reaction area. It is preferable that Thereby, the discharge performance in a metal air battery can further be improved. In addition, the average particle diameter of the conductive ceramic particles constituting the positive electrode body 21 is preferably 0.1 μm or more in order to secure pores of a size sufficient to hold the electrolyte solution. In order to ensure a certain reaction area in the case, it is preferably 2 μm or less. Thereby, the charge performance in a metal air battery can further be improved. The average particle diameter of the ceramic particles is obtained by using an intercept method in an image of a smooth surface obtained by polishing the cross section of the positive electrode 2 using a scanning electron microscope, for example.
　＜実施例１＞
　押出成形法および高温焼成により得られた厚さ２ｍｍ、外径１６ｍｍ、内径１２ｍｍ、長さ７０ｍｍの日立造船社製の円筒型ペロブスカイト酸化物多孔質セラミック支持管（ＬＳＭ、平均細孔径５μｍ）を基盤として、以下に述べるように、スラリーコート法を用いつつ、焼成温度が高い工程順に成膜焼成することで、セパレータが設けられた正極（空気極）を作製した。以下、セラミック支持管を「セラミックチューブ」と呼ぶ。 <Example 1>
Based on a cylindrical perovskite oxide porous ceramic support tube (LSM, average pore diameter 5 μm) manufactured by Hitachi Zosen Corporation with a thickness of 2 mm, an outer diameter of 16 mm, an inner diameter of 12 mm, and a length of 70 mm obtained by extrusion molding and high-temperature firing As described below, a positive electrode (air electrode) provided with a separator was produced by performing film formation and baking in the order of processes having a high baking temperature while using a slurry coating method. Hereinafter, the ceramic support tube is referred to as “ceramic tube”.
　（セパレータ用スラリーの調製１）
　１層目、２層目セパレータ成膜用スラリーは、下記のようにして調製した。アルコール（ソルミックス（登録商標））３に対し、酢酸２－（２－ｎ－ブトキシエトキシ）エチルを１加えた溶液に、３．４重量％のバインダ（エチルセルロース）を塊にならないように攪拌しながら少量ずつ添加した。攪拌はバインダが溶解して溶液が透明になるまで行った。上記のようにして得られた溶液を、予め３２重量％のアルミナ粉末（例えば、昭和電工社製Ａ－４２－６）とφ１０ｍｍの樹脂ボールを入れたポットミル容器に入れて、ボールミルで１０日以上混合攪拌した。 (Preparation of slurry for separator 1)
The first-layer and second-layer separator film-forming slurries were prepared as follows. To a solution obtained by adding 1- (2-n-butoxyethoxy) ethyl acetate to alcohol 3 (Solmix (registered trademark)), stir 3.4% by weight of binder (ethylcellulose) so as not to become a mass. While adding little by little. Stirring was performed until the binder dissolved and the solution became transparent. The solution obtained as described above was previously placed in a pot mill container in which 32% by weight of alumina powder (for example, A-42-6 manufactured by Showa Denko KK) and φ10 mm resin balls were placed, and the ball mill was used for 10 days or more. The mixture was stirred.
　（セパレータ成膜１）
　上記円筒型セラミックチューブの上端にホース状キャップ（ロートの役割をするもの）を装着し、下端は封止栓をした。上端のホース状キャップはスラリーが溢れるのを防止するためのものである。ホース状キャップをしたセラミックチューブの上端から漏斗を使用し、１層目、２層目製膜用スラリーを注入し、セラミックチューブ上部まで満たされた状態で１分間保持した。１分経過後、下端の封止栓を取り外し、スラリーを抜いた。その後、１５時間以上室温で乾燥し、５０℃で２時間以上乾燥させた。２回目はセラミックチューブを上下反転させてこの操作をもう一度繰り返した。その後、セラミックチューブを１２５０℃、４時間焼成することで、内側面に２層のアルミナ膜が積層されたセラミックチューブを得た。 (Separator film formation 1)
A hose-like cap (that functions as a funnel) was attached to the upper end of the cylindrical ceramic tube, and the lower end was sealed with a sealing plug. The hose cap at the upper end is for preventing the slurry from overflowing. Using a funnel from the upper end of the ceramic tube with a hose-like cap, the first layer and second layer slurry for casting were poured and held for 1 minute in a state filled up to the top of the ceramic tube. After 1 minute, the sealing plug at the lower end was removed and the slurry was removed. Then, it dried at room temperature for 15 hours or more, and was dried at 50 degreeC for 2 hours or more. The second time, the ceramic tube was turned upside down and this operation was repeated once more. Thereafter, the ceramic tube was baked at 1250 ° C. for 4 hours to obtain a ceramic tube having two layers of alumina films laminated on the inner surface.
　（触媒層用スラリーの調製）
　触媒層用スラリーは、下記のようにして調製した。アルコール（ソルミックス（登録商標）Ｈ－３７）３に対し、酢酸２－（２－ｎ－ブトキシエトキシ）エチルを１加えた溶液に、３．４重量％のバインダ（エチルセルロース）を塊にならないように攪拌しながら少量ずつ添加し、溶解するまで攪拌した。上記のようにして得られた溶液を、予め３２重量％のＬａＳｒＣｏＦｅＯ３原料粉末とφ１０ｍｍの樹脂ボールを入れたポットミル容器に入れて、ボールミルで１０日以上混合攪拌した。 (Preparation of slurry for catalyst layer)
The slurry for the catalyst layer was prepared as follows. To a solution of alcohol (Solmix (registered trademark) H-37) 3 with 1 2- (2-n-butoxyethoxy) ethyl acetate added, 3.4% by weight of binder (ethylcellulose) should not be agglomerated. Was added in small portions with stirring and stirred until dissolved. The solution obtained as described above was placed in a pot mill container in which 32% by weight of LaSrCoFeO 3 raw material powder and φ10 mm resin balls were previously placed, and mixed and stirred by a ball mill for 10 days or more.
　（触媒層成膜）
　上記円筒型セラミックチューブの上端と下端に封止栓をすることにより、チューブ内側にスラリーが侵入することを防止した。セラミックチューブを、その上端までスラリーに浸漬させた状態で１分間保持した。１分経過後、セラミックチューブをスラリーから引き上げ、スラリーを垂れ切りした。その後、３５℃で３０分以上乾燥し、８０℃で２時間以上乾燥させた。乾燥後のセラミックチューブを１１５０℃、５時間焼成することで、外側面に正極触媒層が形成されたセラミックチューブを得た。 (Catalyst layer deposition)
By sealing plugs at the upper and lower ends of the cylindrical ceramic tube, the slurry was prevented from entering the inside of the tube. The ceramic tube was held for 1 minute while immersed in the slurry up to its upper end. After 1 minute, the ceramic tube was pulled up from the slurry, and the slurry was dripped down. Then, it dried at 35 degreeC for 30 minutes or more, and was dried at 80 degreeC for 2 hours or more. The ceramic tube after drying was fired at 1150 ° C. for 5 hours to obtain a ceramic tube having a positive electrode catalyst layer formed on the outer surface.
　（インターコネクタ用スラリーの調製）
　インターコネクタ成膜用スラリーを、下記の手順で調製した。ソルミックス（登録商標）Ｈ－３７（日本アルコール販売社製）３に対し、酢酸２－（２－ｎ－ブトシキエトキシ）エチル（関東化学社製）１を加えた溶液に、４重量％のバインダ（エチルセルロース（東京化成社製））を塊にならないように攪拌しながら少量ずつ添加し、溶解するまで攪拌した。上記のようにして得られた溶液を、平均粒子径３．７μｍのＬａＳｒＣｏＦｅＯ３（ＬＳＣＦ）粉末２７重量％、φ１０ｍｍの樹脂ボールと共にポットミル容器に入れ、ボールミルで５０時間混合し、インターコネクタ用スラリーを得た。 (Preparation of slurry for interconnectors)
An interconnector film-forming slurry was prepared by the following procedure. To a solution obtained by adding 2- (2-n-butoxyethoxy) ethyl acetate (manufactured by Kanto Chemical Co., Inc.) 1 to Solmix (registered trademark) H-37 (manufactured by Nippon Alcohol Sales Co., Ltd.) 4 wt% A binder (ethyl cellulose (manufactured by Tokyo Chemical Industry Co., Ltd.)) was added little by little with stirring so as not to clump, and stirred until dissolved. The solution obtained as described above was placed in a pot mill container together with 27% by weight of LaSrCoFeO 3 (LSCF) powder having an average particle size of 3.7 μm and a resin ball of φ10 mm, and mixed in a ball mill for 50 hours to prepare an interconnector slurry. Obtained.
　（インターコネクタ成膜）
　正極触媒層が形成されたセラミックチューブの外側面において、幅５ｍｍ、長さ６０ｍｍのインターコネクタを形成させる部分以外の領域をマスキングテープで被覆した。マスキングしたセラミックチューブを、ＬＳＣＦスラリーに１分間浸漬させた後、３５℃で３０分、８０℃で９０分以上乾燥させ、この操作を５回繰り返した後、マスキングテープを剥がし、１１５０℃で４時間焼成することで、正極触媒層の外側面にインターコネクタが形成されたセラミックチューブを得た。 (Interconnector deposition)
On the outer surface of the ceramic tube on which the positive electrode catalyst layer was formed, a region other than the portion for forming the interconnector having a width of 5 mm and a length of 60 mm was covered with a masking tape. The masked ceramic tube was immersed in the LSCF slurry for 1 minute, then dried at 35 ° C. for 30 minutes and at 80 ° C. for 90 minutes or more. After repeating this operation 5 times, the masking tape was peeled off and the temperature was 1150 ° C. for 4 hours. By firing, a ceramic tube having an interconnector formed on the outer surface of the positive electrode catalyst layer was obtained.
　（セパレータ用スラリーの調製２）
　３層目、４層目セパレータ成膜用スラリーは、下記のようにして調製した。アルコール（ソルミックス（登録商標））３に対し、酢酸２－（２－ｎ－ブトキシエトキシ）エチルを１加えた溶液に、２．９重量％のバインダ（エチルセルロース）を塊にならないように攪拌しながら少量ずつ添加した。攪拌はバインダが溶解して溶液が透明になるまで行った。上記のようにして得られた溶液を、予め２０重量％のジルコニア粉末（例えば、東ソー社製ＴＺ－０）とφ１０ｍｍのナイロン樹脂ボールを入れたナイロン樹脂ポット容器に入れて、ボールミルで１０日以上混合攪拌した。 (Preparation of slurry for separator 2)
The third-layer and fourth-layer separator film-forming slurries were prepared as follows. To a solution obtained by adding 1- (2-n-butoxyethoxy) ethyl acetate to alcohol (Solmix (registered trademark)) 3, 2.9% by weight of binder (ethylcellulose) was stirred so as not to clump. While adding little by little. Stirring was performed until the binder dissolved and the solution became transparent. The solution obtained as described above is placed in a nylon resin pot container in which 20% by weight of zirconia powder (for example, TZ-0 manufactured by Tosoh Corporation) and a φ10 mm nylon resin ball are placed in advance, and the ball mill is used for 10 days or more. The mixture was stirred.
　（セパレータ成膜２）
　内側面に２層のアルミナ膜が積層されたセラミックチューブの上端にホース状キャップ、下端に封止栓を装着した。ホース状キャップを装着したセラミックチューブの上端から漏斗を使用し、３層目、４層目成膜用スラリーを注入し、セラミックチューブ上部まで満たされた状態で１分間保持した。１分経過後、下端の封止栓を取り外し、スラリーを抜いた。その後、１５時間以上室温で乾燥し、５０℃で２時間以上乾燥させた。乾燥後のセラミックチューブを１０００℃、４時間焼成することで、内側面に３層の膜（２層のアルミナ膜および１層のジルコニア膜）が積層されたセラミックチューブを得た。 (Separator film formation 2)
A hose-like cap was attached to the upper end of the ceramic tube in which two layers of alumina films were laminated on the inner surface, and a sealing plug was attached to the lower end. Using a funnel from the upper end of the ceramic tube equipped with a hose-like cap, the third layer and fourth layer film-forming slurries were injected and held for 1 minute in a state of being filled up to the top of the ceramic tube. After 1 minute, the sealing plug at the lower end was removed and the slurry was removed. Then, it dried at room temperature for 15 hours or more, and was dried at 50 degreeC for 2 hours or more. The dried ceramic tube was fired at 1000 ° C. for 4 hours to obtain a ceramic tube in which three layers of films (two layers of alumina film and one layer of zirconia film) were laminated on the inner surface.
　引き続き、当該セラミックチューブを３層目成膜時とは上下を反対にして同様に上端にホース状キャップ、下端に封止栓を装着した。ホース状キャップをしたセラミックチューブの上端から、３層目成膜で使用したものと同じスラリーを注入し、セラミックチューブの上部まで満たした状態で１分間保持した。１分経過後、下端の封止栓を取り外し、スラリーを抜いた。その後、１５時間以上室温で乾燥し、５０℃で２時間以上乾燥させた。乾燥後のセラミックチューブを１０００℃、４時間焼成することで、内側面に４層の膜（２層のアルミナ膜および２層のジルコニア膜）が積層されたセラミックチューブを得た。 Subsequently, the ceramic tube was mounted with a hose-like cap at the upper end and a sealing plug at the lower end in the same manner upside down from when the third layer was formed. The same slurry as that used in the third-layer film formation was poured from the upper end of the ceramic tube with a hose-shaped cap, and the slurry was held for 1 minute while filling up to the upper part of the ceramic tube. After 1 minute, the sealing plug at the lower end was removed and the slurry was removed. Then, it dried at room temperature for 15 hours or more, and was dried at 50 degreeC for 2 hours or more. The dried ceramic tube was baked at 1000 ° C. for 4 hours to obtain a ceramic tube in which four layers of films (two layers of alumina film and two layers of zirconia film) were laminated on the inner surface.
　（撥液層用スラリーの調製）
　三井デュポン社製ＦＥＰディスパージョン原液を２０重量％に希釈し、増粘剤としてアルコックス（登録商標）Ｅ－３０を２．８重量％秤量し、ＦＥＰ希釈溶液に増粘剤が塊にならないように撹拌しながら少量ずつ添加した。 (Preparation of slurry for liquid repellent layer)
Dilute Mitsui DuPont's FEP dispersion stock solution to 20% by weight, weigh 2.8% by weight of Alcox (registered trademark) E-30 as a thickener, and avoid thickening the thickener in the FEP diluted solution. Was added in small portions with stirring.
　（撥液層成膜）
　セラミックチューブのインターコネクタ部分に、撥液層（撥水層）がインターコネクタと重なる部分の幅が１ｍｍになるようにテープで被覆し、上述のディスパージョンに１分間浸漬させ、室温・３０分、６０℃・１５時間乾燥させ、２８０℃、５０分間焼成することで撥液層が形成されたセラミックチューブを得た。 (Liquid repellent layer deposition)
The interconnector part of the ceramic tube is covered with tape so that the width of the part where the liquid repellent layer (water repellent layer) overlaps with the interconnector is 1 mm, immersed in the above-mentioned dispersion for 1 minute, room temperature, 30 minutes, The ceramic tube in which the liquid repellent layer was formed was obtained by drying at 60 ° C. for 15 hours and firing at 280 ° C. for 50 minutes.
　（サンプル評価）
　得られたサンプルに対して、Ｎ２ガス透過試験によりガス透過性能を評価し、耐水圧試験により耐水圧性能を評価した。円筒型ペロブスカイト酸化物多孔質セラミックチューブのガス透過性能は、２０２７ｍ３／（ｍ２・ｈ・ａｔｍ）であったのに対し、セパレータ、正極触媒層、インターコネクタおよび撥液層を形成したセラミックチューブのガス透過性能は、１１７ｍ３／（ｍ２・ｈ・ａｔｍ）となった。また、セラミックチューブの内側に水を満たし、Ｎ２ガスで徐々に加圧した耐水圧試験の結果、０．０４５ＭＰａで漏水が確認された。 (sample test)
The obtained sample was evaluated for gas permeation performance by an N 2 gas permeation test, and was evaluated for water pressure resistance by a water pressure resistance test. The gas permeation performance of the cylindrical perovskite oxide porous ceramic tube was 2027 m 3 / (m 2 · h · atm), whereas the separator, the positive electrode catalyst layer, the interconnector and the liquid repellent layer were formed. The gas permeation performance was 117 m 3 / (m 2 · h · atm). Moreover, as a result of a water pressure test in which the inside of the ceramic tube was filled with water and was gradually pressurized with N 2 gas, water leakage was confirmed at 0.045 MPa.
　（電池性能評価）
　得られた正極（空気極）の内側にＺｎを２ｇ電析させたＣｕコイル（負極）を挿入し、電解液（７Ｍ－ＫＯＨ＋０．６５Ｍ－ＺｎＯ）を正極の内側に循環させ、室温にて電池性能評価を実施した。その結果、放電では、電流密度５４．５ｍＡ／ｃｍ２で電圧０．６９Ｖとなり、出力密度は０．０３８Ｗ／ｃｍ２となった。充電では、電流密度５２．９ｍＡ／ｃｍ２で電圧２．０５Ｖとなった。なお、放電では、放電電圧が高いほど高性能であり、出力密度が大きいほど高性能である（出力密度（Ｗ／ｃｍ２）＝電流密度（Ａ／ｃｍ２）×電圧（Ｖ））。充電では、充電電圧が低いほど高性能である。 (Battery performance evaluation)
A Cu coil (negative electrode) on which 2 g of Zn was electrodeposited was inserted inside the obtained positive electrode (air electrode), and an electrolyte solution (7M-KOH + 0.65M-ZnO) was circulated inside the positive electrode. Performance evaluation was performed. As a result, in discharging, the voltage was 0.69 V at a current density of 54.5 mA / cm 2 , and the output density was 0.038 W / cm 2 . In charging, the voltage was 2.05 V at a current density of 52.9 mA / cm 2 . In the discharge, the higher the discharge voltage, the higher the performance, and the higher the output density, the higher the performance (output density (W / cm 2 ) = current density (A / cm 2 ) × voltage (V)). In charging, the lower the charging voltage, the higher the performance.
　＜比較例１＞
　押出成形法および高温焼成により得られた厚さ２ｍｍ、外径１６ｍｍ、内径１２ｍｍ、長さ７０ｍｍの日立造船社製の円筒型アルミナ多孔質セラミックチューブ（Ａｌ２Ｏ３、平均細孔径１０μｍ）を基盤として、以下に述べるように、スラリーコート法を用いつつ、焼成温度が高い工程順に成膜焼成することで、比較例の正極を作製した。なお、比較例の正極では、後述の導電層とセパレータとの間の界面に反応相が形成されることを抑制する緩衝層が設けられる。 <Comparative Example 1>
Based on a cylindrical alumina porous ceramic tube (Al 2 O 3 , average pore diameter of 10 μm) made by Hitachi Zosen with a thickness of 2 mm, an outer diameter of 16 mm, an inner diameter of 12 mm, and a length of 70 mm obtained by extrusion molding and high-temperature firing As described below, a positive electrode of a comparative example was manufactured by performing film formation and baking in the order of processes having a high baking temperature while using a slurry coating method. Note that the positive electrode of the comparative example is provided with a buffer layer that suppresses the formation of a reaction phase at the interface between a conductive layer and a separator described later.
　（緩衝層用スラリーの調製）
　緩衝層用スラリーは、下記のようにして調製した。アルコール（ソルミックス（登録商標）Ｈ－３７）３に対し、酢酸２－（２－ｎ－ブトキシエトキシ）エチルを１加えた溶液に、３．４重量％のバインダ（エチルセルロース）を塊にならないように攪拌しながら少量ずつ添加し、溶解するまで攪拌した。上記のようにして得られた溶液を、予め３２重量％のＬａＳｒＣｏＭｎＦｅＯ３原料粉末とφ１０ｍｍの樹脂ボールを入れたポットミル容器に入れて、ボールミルで１０日以上混合攪拌した。 (Preparation of slurry for buffer layer)
The buffer layer slurry was prepared as follows. To a solution of alcohol (Solmix (registered trademark) H-37) 3 with 1 2- (2-n-butoxyethoxy) ethyl acetate added, 3.4% by weight of binder (ethylcellulose) should not be agglomerated. Was added in small portions with stirring and stirred until dissolved. The solution obtained as described above was put in a pot mill container in which 32% by weight of LaSrCoMnFeO 3 raw material powder and φ10 mm resin balls were previously placed, and mixed and stirred for 10 days or more by a ball mill.
　（導電層用スラリーの調製）
　導電層用スラリーは、下記のようにして調製した。アルコール（ソルミックス（登録商標）Ｈ－３７）３に対し、酢酸２－（２－ｎ－ブトキシエトキシ）エチルを１加えた溶液に、３．４重量％のバインダ（エチルセルロース）を塊にならないように攪拌しながら少量ずつ添加し、溶解するまで攪拌した。上記のようにして得られた溶液を、予め３２重量％のＬａＳｒＣｏＦｅＯ３原料粉末とφ１０ｍｍの樹脂ボールを入れたポットミル容器に入れて、ボールミルで１０日以上混合攪拌した。 (Preparation of slurry for conductive layer)
The slurry for conductive layers was prepared as follows. To a solution of alcohol (Solmix (registered trademark) H-37) 3 with 1 2- (2-n-butoxyethoxy) ethyl acetate added, 3.4% by weight of binder (ethylcellulose) should not be agglomerated. Was added in small portions with stirring and stirred until dissolved. The solution obtained as described above was placed in a pot mill container in which 32% by weight of LaSrCoFeO 3 raw material powder and φ10 mm resin balls were previously placed, and mixed and stirred by a ball mill for 10 days or more.
　（触媒層用スラリーの調製）
　触媒層用スラリーは、下記のようにして調製した。アルコール（ソルミックス（登録商標）Ｈ－３７）３に対し、酢酸２－（２－ｎ－ブトキシエトキシ）エチルを１加えた溶液に、３．４重量％のバインダ（エチルセルロース）を塊にならないように攪拌しながら少量ずつ添加し、溶解するまで攪拌した。上記のようにして得られた溶液を、予め３２重量％のＬａＳｒＭｎＦｅＯ３原料粉末とφ１０ｍｍの樹脂ボールを入れたポットミル容器に入れて、ボールミルで１０日以上混合攪拌した。 (Preparation of slurry for catalyst layer)
The slurry for the catalyst layer was prepared as follows. To a solution of alcohol (Solmix (registered trademark) H-37) 3 with 1 2- (2-n-butoxyethoxy) ethyl acetate added, 3.4% by weight of binder (ethylcellulose) should not be agglomerated. Was added in small portions with stirring and stirred until dissolved. The solution obtained as described above was placed in a pot mill container in which 32% by weight of LaSrMnFeO 3 raw material powder and φ10 mm resin balls were previously placed, and mixed and stirred for 10 days or more in a ball mill.
　（緩衝層成膜、導電層成膜、触媒層成膜）
　上記円筒型セラミックチューブの上端と下端に封止栓をすることにより、チューブ内側にスラリーが侵入することを防止した。緩衝層用スラリーに、セラミックチューブをその上端まで浸漬させた状態で１分間保持した。１分経過後、セラミックチューブをスラリーから引き上げ、スラリーを垂れ切りした。その後、３５℃で３０分以上乾燥し、８０℃で９０分以上乾燥させた。この操作を２回繰り返した。 (Buffer layer deposition, conductive layer deposition, catalyst layer deposition)
By sealing plugs at the upper and lower ends of the cylindrical ceramic tube, the slurry was prevented from entering the inside of the tube. The ceramic tube was held for 1 minute in the state where the ceramic tube was immersed in the buffer layer slurry. After 1 minute, the ceramic tube was pulled up from the slurry, and the slurry was dripped down. Then, it dried at 35 degreeC for 30 minutes or more, and was dried at 80 degreeC for 90 minutes or more. This operation was repeated twice.
　引き続き、導電層用スラリーに、セラミックチューブをその上端まで浸漬させた状態で１分間保持した。１分経過後、セラミックチューブをスラリーから引き上げ、スラリーを垂れ切りした。その後、３５℃で３０分以上乾燥し、８０℃で９０分以上乾燥させた。緩衝層と導電層の合計３回浸漬・乾燥後のセラミックチューブ（支持体）を１３２５℃、４時間焼成した。 Subsequently, the ceramic tube was immersed in the slurry for the conductive layer to the upper end thereof and held for 1 minute. After 1 minute, the ceramic tube was pulled up from the slurry, and the slurry was dripped down. Then, it dried at 35 degreeC for 30 minutes or more, and was dried at 80 degreeC for 90 minutes or more. The ceramic tube (support) after the immersion and drying of the buffer layer and the conductive layer three times in total was fired at 1325 ° C. for 4 hours.
　更に、導電層用スラリーに、セラミックチューブをその上端まで浸漬させた状態で１分間保持した。１分経過後、セラミックチューブをスラリーから引き上げ、スラリーを垂れ切りした。その後、３５℃で３０分以上乾燥し、８０℃で９０分以上乾燥させた。この操作を３回繰り返した後のセラミックチューブを１３２５℃、４時間焼成した。 Further, the ceramic tube was held in the slurry for the conductive layer for 1 minute in a state where the ceramic tube was immersed up to its upper end. After 1 minute, the ceramic tube was pulled up from the slurry, and the slurry was dripped down. Then, it dried at 35 degreeC for 30 minutes or more, and was dried at 80 degreeC for 90 minutes or more. The ceramic tube after repeating this operation three times was fired at 1325 ° C. for 4 hours.
　更に、導電層用スラリーに、セラミックチューブをその上端まで浸漬させた状態で１分間保持した。１分経過後、セラミックチューブをスラリーから引き上げ、スラリーを垂れ切りした。その後、３５℃で３０分以上乾燥し、８０℃で９０分以上乾燥させた。この操作を３回繰り返した後、引き続き、触媒層用スラリーに、セラミックチューブをその上端まで浸漬させた状態で１分間保持した。１分経過後、セラミックチューブをスラリーから引き上げ、スラリーを垂れ切りした。その後、３５℃で３０分以上乾燥し、８０℃で９０分以上乾燥させた。導電層と触媒層の合計４回の浸漬・乾燥後のセラミックチューブを１３２５℃、４時間焼成した。 Further, the ceramic tube was held in the slurry for the conductive layer for 1 minute in a state where the ceramic tube was immersed up to its upper end. After 1 minute, the ceramic tube was pulled up from the slurry, and the slurry was dripped down. Then, it dried at 35 degreeC for 30 minutes or more, and was dried at 80 degreeC for 90 minutes or more. After this operation was repeated three times, the ceramic tube was continuously held in the slurry for the catalyst layer for 1 minute in a state where the ceramic tube was immersed up to its upper end. After 1 minute, the ceramic tube was pulled up from the slurry, and the slurry was dripped down. Then, it dried at 35 degreeC for 30 minutes or more, and was dried at 80 degreeC for 90 minutes or more. The ceramic tube after the immersion and drying of the conductive layer and the catalyst layer four times in total was fired at 1325 ° C. for 4 hours.
　以上の工程により、緩衝層、導電層、触媒層が形成されたセラミックチューブを得た。 Through the above steps, a ceramic tube having a buffer layer, a conductive layer, and a catalyst layer was obtained.
　（セパレータ用スラリーの調製１）
　１層目、２層目セパレータ成膜用スラリーは、下記のようにして調製した。アルコール（ソルミックス（登録商標））３に対し、酢酸２－（２－ｎ－ブトキシエトキシ）エチルを１加えた溶液に、３．４重量％のバインダ（エチルセルロース）を塊にならないように攪拌しながら少量ずつ添加した。攪拌はバインダが溶解して溶液が透明になるまで行った。上記のようにして得られた溶液を、予め３２重量％のアルミナ粉末（例えば、昭和電工社製Ａ－４２－６）とφ１０ｍｍの樹脂ボールを入れたポットミル容器に入れて、ボールミルで１０日以上混合攪拌した。 (Preparation of slurry for separator 1)
The first-layer and second-layer separator film-forming slurries were prepared as follows. To a solution obtained by adding 1- (2-n-butoxyethoxy) ethyl acetate to alcohol 3 (Solmix (registered trademark)), stir 3.4% by weight of binder (ethylcellulose) so as not to become a mass. While adding little by little. Stirring was performed until the binder dissolved and the solution became transparent. The solution obtained as described above was previously placed in a pot mill container in which 32% by weight of alumina powder (for example, A-42-6 manufactured by Showa Denko KK) and φ10 mm resin balls were placed, and the ball mill was used for 10 days or more. The mixture was stirred.
　（セパレータ成膜１）
　上記円筒型セラミックチューブの上端にホース状キャップ（ロートの役割をするもの）を装着し、下端は封止栓をした。上端のホース状キャップはスラリーが溢れるのを防止するためのものである。ホース状キャップをしたセラミックチューブの上端から漏斗を使用し、１層目製膜用スラリーを注入し、セラミックチューブ上部まで満たされた状態で１分間保持した。１分経過後、下端の封止栓を取り外し、スラリーを抜いた。その後、１５時間以上室温で乾燥し、５０℃で２時間以上乾燥させた。この操作を２回繰り返した後のセラミックチューブを１２５０℃、４時間焼成することで、内側面に２層のアルミナ膜が積層されたセラミックチューブを得た。なお、当該アルミナ膜の細孔径は、セラミックチューブの細孔径よりも小さく、当該アルミナ膜は、デンドライトの貫通を防止するためのものである（後述のジルコニア膜において同様）。 (Separator film formation 1)
A hose-like cap (that functions as a funnel) was attached to the upper end of the cylindrical ceramic tube, and the lower end was sealed with a sealing plug. The hose cap at the upper end is for preventing the slurry from overflowing. Using a funnel from the upper end of the ceramic tube with a hose-like cap, the slurry for forming the first layer was poured, and the ceramic tube was held for 1 minute while being filled to the top of the ceramic tube. After 1 minute, the sealing plug at the lower end was removed and the slurry was removed. Then, it dried at room temperature for 15 hours or more, and was dried at 50 degreeC for 2 hours or more. The ceramic tube after repeating this operation twice was fired at 1250 ° C. for 4 hours to obtain a ceramic tube in which two layers of alumina films were laminated on the inner surface. Note that the pore diameter of the alumina film is smaller than the pore diameter of the ceramic tube, and the alumina film is for preventing penetration of dendrites (the same applies to the zirconia film described later).
　（インターコネクタ用スラリーの調製）
　インターコネクタ成膜用スラリーを、下記の手順で調製した。ソルミックス（登録商標）Ｈ－３７（日本アルコール販売社製）３に対し、酢酸２－（２－ｎ－ブトシキエトキシ）エチル（関東化学社製）１を加えた溶液に、４重量％のバインダ（エチルセルロース（東京化成社製））を塊にならないように攪拌しながら少量ずつ添加し、溶解するまで攪拌した。上記のようにして得られた溶液を、平均粒子径３．７μｍのＬａＳｒＣｏＦｅＯ３粉末２７重量％、φ１０ｍｍの樹脂ボールと共にポットミル容器に入れ、ボールミルで５０時間混合し、インターコネクタ用スラリーを得た。 (Preparation of slurry for interconnectors)
An interconnector film-forming slurry was prepared by the following procedure. To a solution obtained by adding 2- (2-n-butoxyethoxy) ethyl acetate (manufactured by Kanto Chemical Co., Inc.) 1 to Solmix (registered trademark) H-37 (manufactured by Nippon Alcohol Sales Co., Ltd.) 4 wt% A binder (ethyl cellulose (manufactured by Tokyo Chemical Industry Co., Ltd.)) was added little by little with stirring so as not to clump, and stirred until dissolved. The solution obtained as described above was placed in a pot mill container together with 27% by weight of LaSrCoFeO 3 powder having an average particle diameter of 3.7 μm and a resin ball of φ10 mm, and mixed in a ball mill for 50 hours to obtain an interconnector slurry.
　（インターコネクタ成膜）
　触媒層を形成した上記セラミックチューブの外側面において、幅５ｍｍ、長さ６０ｍｍのインターコネクタを形成させる部分以外の領域をマスキングテープで被覆した。マスキングしたセラミックチューブを、ＬＳＣＦスラリーに１分間浸漬させ、３５℃で３０分、８０℃で９０分以上乾燥させ、この操作を５回繰り返した後、マスキングテープを剥がし、１１５０℃で４時間焼成することでインターコネクタが形成されたセラミックチューブを得た。 (Interconnector deposition)
On the outer surface of the ceramic tube on which the catalyst layer was formed, a region other than the portion where the interconnector having a width of 5 mm and a length of 60 mm was formed was covered with a masking tape. The masked ceramic tube is immersed in the LSCF slurry for 1 minute, dried at 35 ° C. for 30 minutes and at 80 ° C. for 90 minutes or more. After repeating this operation 5 times, the masking tape is peeled off and fired at 1150 ° C. for 4 hours. Thus, a ceramic tube in which an interconnector was formed was obtained.
　（セパレータ用スラリーの調製２）
　３層目、４層目セパレータ成膜用スラリーは、下記のようにして調製した。アルコール（ソルミックス（登録商標））３に対し、酢酸２－（２－ｎ－ブトキシエトキシ）エチルを１加えた溶液に、２．９重量％のバインダ（エチルセルロース）を塊にならないように攪拌しながら少量ずつ添加した。攪拌はバインダが溶解して溶液が透明になるまで行った。上記のようにして得られた溶液を、予め２０重量％のジルコニア粉末（例えば、東ソー社製ＴＺ－０）とφ１０ｍｍのナイロン樹脂ボールを入れたナイロン樹脂ポット容器に入れて、ボールミルで１０日以上混合攪拌した。 (Preparation of slurry for separator 2)
The third-layer and fourth-layer separator film-forming slurries were prepared as follows. To a solution obtained by adding 1- (2-n-butoxyethoxy) ethyl acetate to alcohol (Solmix (registered trademark)) 3, 2.9% by weight of binder (ethylcellulose) was stirred so as not to clump. While adding little by little. Stirring was performed until the binder dissolved and the solution became transparent. The solution obtained as described above is placed in a nylon resin pot container in which 20% by weight of zirconia powder (for example, TZ-0 manufactured by Tosoh Corporation) and a φ10 mm nylon resin ball are placed in advance, and the ball mill is used for 10 days or more. The mixture was stirred.
　（セパレータ成膜２）
　内側面に２層のアルミナ膜が積層されたセラミックチューブ上端にホース状キャップ、下端に封止栓を装着した。ホース状キャップをしたセラミックチューブの上端から漏斗を使用し、３層目、４層目成膜用スラリーを注入し、セラミックチューブ上部まで満たされた状態で１分間保持した。１分経過後、下端の封止栓を取り外し、スラリーを抜いた。その後、１５時間以上室温で乾燥し、５０℃で２時間以上乾燥させた。乾燥後のセラミックチューブを１０００℃、４時間焼成することで、内側面に３層の膜（２層のアルミナ膜および１層のジルコニア膜）が積層されたセラミックチューブを得た。 (Separator film formation 2)
A hose-like cap was attached to the upper end of the ceramic tube in which two layers of alumina films were laminated on the inner surface, and a sealing plug was attached to the lower end. Using a funnel from the upper end of the ceramic tube with a hose-like cap, the third layer and fourth layer film-forming slurries were poured and held for 1 minute in a state where it was filled up to the top of the ceramic tube. After 1 minute, the sealing plug at the lower end was removed and the slurry was removed. Then, it dried at room temperature for 15 hours or more, and was dried at 50 degreeC for 2 hours or more. The dried ceramic tube was fired at 1000 ° C. for 4 hours to obtain a ceramic tube in which three layers of films (two layers of alumina film and one layer of zirconia film) were laminated on the inner surface.
　引き続き、当該セラミックチューブを３層目成膜時とは上下を反対にして同様に上端にホース状キャップ、下端に封止栓を装着した。ホース状キャップをしたセラミックチューブの上端から、３層目成膜で使用したものと同じスラリーを注入し、セラミックチューブの上部まで満たした状態で１分間保持した。１分経過後、下端の封止栓を取り外し、スラリーを抜いた。その後、１５時間以上室温で乾燥し、５０℃で２時間以上乾燥させた。乾燥後のセラミックチューブを１０００℃、４時間焼成することで、内側面に４層の膜（２層のアルミナ膜および２層のジルコニア膜）が積層されたセラミックチューブを得た。 Subsequently, the ceramic tube was mounted with a hose-like cap at the upper end and a sealing plug at the lower end in the same manner upside down from when the third layer was formed. The same slurry as that used in the third-layer film formation was poured from the upper end of the ceramic tube with a hose-shaped cap, and the slurry was held for 1 minute while filling up to the upper part of the ceramic tube. After 1 minute, the sealing plug at the lower end was removed and the slurry was removed. Then, it dried at room temperature for 15 hours or more, and was dried at 50 degreeC for 2 hours or more. The dried ceramic tube was baked at 1000 ° C. for 4 hours to obtain a ceramic tube in which four layers of films (two layers of alumina film and two layers of zirconia film) were laminated on the inner surface.
　（撥液層用スラリーの調製）
　三井デュポン社製ＦＥＰディスパージョン原液を２０重量％に希釈し、増粘剤としてアルコックス（登録商標）Ｅ－３０を２．８重量％秤量し、ＦＥＰ希釈溶液に増粘剤が塊にならないように撹拌しながら少量ずつ添加した。 (Preparation of slurry for liquid repellent layer)
Dilute Mitsui DuPont's FEP dispersion stock solution to 20% by weight, weigh 2.8% by weight of Alcox (registered trademark) E-30 as a thickener, and avoid thickening the thickener in the FEP diluted solution. Was added in small portions with stirring.
　（撥液層成膜）
　セラミックチューブのインターコネクタ部分に、撥液層がインターコネクタと重なる部分の幅が１ｍｍになるようにテープで被覆し、上述のディスパージョンに１分間浸漬させ、室温・３０分、６０℃・１５時間乾燥させ、２８０℃、５０分間焼成することで撥液層を形成したセラミックチューブを得た。 (Liquid repellent layer deposition)
The interconnector part of the ceramic tube is covered with tape so that the width of the part where the liquid repellent layer overlaps the interconnector is 1 mm, and immersed in the above dispersion for 1 minute, at room temperature / 30 minutes, 60 ° C./15 hours The ceramic tube which formed the liquid repellent layer by drying and baking at 280 degreeC for 50 minutes was obtained.
　（サンプル評価）
　得られたサンプルに対して、Ｎ２ガス透過試験によりガス透過性能を評価し、耐水圧試験により耐水圧性能を評価した。円筒型アルミナ多孔質セラミックチューブのガス透過性能は、３０１５ｍ３／（ｍ２・ｈ・ａｔｍ）であったのに対し、緩衝層、導電層、触媒層、セパレータ、インターコネクタおよび撥液層を形成したセラミックチューブのガス透過性能は、９３ｍ３／（ｍ２・ｈ・ａｔｍ）となった。また、セラミックチューブの内側に水を満たし、Ｎ２ガスで徐々に加圧した耐水圧試験の結果、０．０６５ＭＰａで漏水が確認された。 (sample test)
The obtained sample was evaluated for gas permeation performance by an N 2 gas permeation test, and was evaluated for water pressure resistance by a water pressure resistance test. The gas permeation performance of the cylindrical alumina porous ceramic tube was 3015 m 3 / (m 2 · h · atm), while the buffer layer, conductive layer, catalyst layer, separator, interconnector and liquid repellent layer were formed. The gas permeation performance of the obtained ceramic tube was 93 m 3 / (m 2 · h · atm). Further, as a result of a water pressure test in which the inside of the ceramic tube was filled with water and was gradually pressurized with N 2 gas, water leakage was confirmed at 0.065 MPa.
　（電池評価）
　得られた正極（空気極）の内側にＺｎを２ｇ電析させたＣｕコイル（負極）を挿入し、電解液（７Ｍ－ＫＯＨ＋０．６５Ｍ－ＺｎＯ）を正極の内側に循環させ、室温にて電池性能評価を実施した。その結果、放電では、電流密度２．３ｍＡ／ｃｍ２で電圧０．７０Ｖに達し、出力密度は０．００２Ｗ／ｃｍ２であった。充電では、電流密度２５ｍＡ／ｃｍ２で電圧１５Ｖに達した。 (Battery evaluation)
A Cu coil (negative electrode) on which 2 g of Zn was electrodeposited was inserted inside the obtained positive electrode (air electrode), and an electrolyte solution (7M-KOH + 0.65M-ZnO) was circulated inside the positive electrode. Performance evaluation was performed. As a result, in discharge, the voltage reached 0.70 V at a current density of 2.3 mA / cm 2 and the output density was 0.002 W / cm 2 . In charging, the voltage reached 15 V at a current density of 25 mA / cm 2 .
　図４は、実施例１の正極を用いた金属空気電池、および、比較例１の正極を用いた金属空気電池の充放電特性を示す図である。図５は、実施例１の正極を用いた金属空気電池、および、比較例１の正極を用いた金属空気電池の出力密度を示す図である。図４から判るように、実施例１の正極、すなわち、正極本体を支持体とする正極を用いた金属空気電池では、比較例１の正極、すなわち、セパレータを支持体とする正極を用いた金属空気電池よりも放電電圧が高く（図４中のＬ１，Ｌ２参照）、充電電圧が低い（図４中のＬ３，Ｌ４参照）。また、図５から判るように、実施例１の正極を用いた金属空気電池では、比較例１の正極を用いた金属空気電池よりも出力密度が高い。このように、実施例１の正極を用いた金属空気電池では、比較例１の正極を用いた金属空気電池よりも電池性能が高いといえる。なお、実施例１の正極の作製に要する時間は、比較例の正極の作製に要する時間の２／３程度である。 FIG. 4 is a graph showing charge / discharge characteristics of a metal-air battery using the positive electrode of Example 1 and a metal-air battery using the positive electrode of Comparative Example 1. FIG. 5 is a diagram showing the output density of the metal-air battery using the positive electrode of Example 1 and the metal-air battery using the positive electrode of Comparative Example 1. As can be seen from FIG. 4, in the metal-air battery using the positive electrode of Example 1, that is, the positive electrode using the positive electrode body as a support, the metal using the positive electrode of Comparative Example 1, that is, the positive electrode using the separator as a support. The discharge voltage is higher than that of the air battery (see L1 and L2 in FIG. 4) and the charge voltage is low (see L3 and L4 in FIG. 4). Further, as can be seen from FIG. 5, the metal-air battery using the positive electrode of Example 1 has a higher output density than the metal-air battery using the positive electrode of Comparative Example 1. Thus, it can be said that the metal-air battery using the positive electrode of Example 1 has higher battery performance than the metal-air battery using the positive electrode of Comparative Example 1. The time required for producing the positive electrode of Example 1 is about 2/3 of the time required for producing the positive electrode of the comparative example.
　＜実施例２＞
　ＬａＳｒＭｎＯ３（ＬＳＭ）粉末、および、ＬａＳｒＣｏＦｅＯ３（ＬＳＣＦ）粉末（共に共立マテリアル社製）に対してカッターミルでの粗粉砕、および、ジェットミル（日清エンジニアリング社製）での微粉砕を行った後、ターボクラシファイアで分級を行うことにより、様々な粒径のＬＳＭ粉末およびＬＳＣＦ粉末を得た。そして、実施例１と同様の手法により、図６中の「正極本体（充電反応層）」の欄に記す材料（触媒種）および粒径（平均粒径）の組合せにて正極本体であるセラミックチューブを形成し、「正極触媒層（放電反応層）」の欄に記す材料および粒径の組合せにて正極触媒層を当該セラミックチューブの外側面に形成した。図６中の「厚さ比率」の欄には、正極触媒層の厚さＴ１と正極本体（セラミックチューブ）の厚さＴ２の比率（Ｔ１：Ｔ２）を示している。 <Example 2>
LaSrMnO 3 (LSM) powder and LaSrCoFeO 3 (LSCF) powder (both manufactured by Kyoritsu Materials Co., Ltd.) were coarsely pulverized by a cutter mill and finely pulverized by a jet mill (Nisshin Engineering Co., Ltd.). Thereafter, classification was performed with a turbo classifier to obtain LSM powder and LSCF powder having various particle sizes. Then, according to the same method as in Example 1, the ceramic which is the positive electrode main body in the combination of the material (catalyst type) and the particle size (average particle size) described in the column of “Positive electrode main body (charge reaction layer)” in FIG. A tube was formed, and a positive electrode catalyst layer was formed on the outer surface of the ceramic tube with a combination of materials and particle sizes described in the column of “positive electrode catalyst layer (discharge reaction layer)”. In the column of “thickness ratio” in FIG. 6, the ratio (T1: T2) between the thickness T1 of the positive electrode catalyst layer and the thickness T2 of the positive electrode main body (ceramic tube) is shown.
　上記のようにして作製した正極サンプルの内側に、Ｚｎを２ｇ電析させたＣｕコイルを負極として挿入し、電解液（７Ｍ（モーラー）のＫＯＨおよび０．６５ＭのＺｎＯ（酸化亜鉛）を含む。）を内側に循環させ、室温にて電池の放電および充電特性を測定した。図６では、最も左側の列に正極サンプルの番号を記し、「放電性能」および「充電性能」の欄に、各サンプルを用いた金属空気電池において、出力密度が１０ｍＡ／ｃｍ２である際の電圧を示している。加えて、「放電性能」においては、当該電圧が１．２Ｖ以上である場合に◎を記し、１．２Ｖ未満０．８Ｖ以上である場合に〇を記し、０．８Ｖ未満０．６Ｖ以上である場合に△を記している。「充電性能」においては、当該電圧が１．８Ｖ以下である場合に◎を記し、１．８Ｖよりも大きく、２．０Ｖ以下である場合に〇を記し、２．０Ｖよりも大きく、２．２Ｖ以下である場合に△を記している。 A Cu coil in which 2 g of Zn is electrodeposited is inserted as the negative electrode inside the positive electrode sample prepared as described above, and contains an electrolytic solution (7M (molar) KOH and 0.65M ZnO (zinc oxide)). ) Was circulated inward, and the discharge and charge characteristics of the battery were measured at room temperature. In FIG. 6, the number of the positive electrode sample is written in the leftmost column, and in the “discharge performance” and “charge performance” columns, in the metal-air battery using each sample, the output density is 10 mA / cm 2 . The voltage is shown. In addition, in the “discharge performance”, ◎ is marked when the voltage is 1.2 V or more, ◯ is marked when the voltage is less than 1.2 V and 0.8 V or more, and less than 0.8 V and 0.6 V or more. △ is marked in some cases. In “charging performance”, when the voltage is 1.8 V or less, “◎” is marked, and when it is larger than 1.8 V and 2.0 V or smaller, “◯” is marked, and larger than 2.0 V. When it is 2 V or less, Δ is marked.
　図６中の１ないし５番のサンプルの放電性能の結果から、正極触媒層を形成する粒子の平均粒径が１μｍ以上かつ１０μｍ以下であることにより、金属空気電池の放電性能が向上するといえる。正極触媒層においてガス拡散性をより確実に保持するという観点では、正極触媒層を形成する粒子の平均粒径が２μｍ以上であることが好ましい。一方、放電反応層である正極触媒層では、反応有効面積の減少により放電性能が低下する。したがって、より高い放電性能を確保するという観点では、正極触媒層を形成する粒子の平均粒径を６μｍ以下として、ある程度の反応有効面積を確保することが好ましい。 From the results of the discharge performance of the samples No. 1 to No. 5 in FIG. 6, it can be said that the discharge performance of the metal-air battery is improved when the average particle diameter of the particles forming the positive electrode catalyst layer is 1 μm or more and 10 μm or less. From the viewpoint of more reliably maintaining gas diffusibility in the positive electrode catalyst layer, the average particle size of the particles forming the positive electrode catalyst layer is preferably 2 μm or more. On the other hand, in the positive electrode catalyst layer that is the discharge reaction layer, the discharge performance is lowered due to the reduction of the reaction effective area. Therefore, from the viewpoint of securing higher discharge performance, it is preferable to secure a certain effective reaction area by setting the average particle diameter of the particles forming the positive electrode catalyst layer to 6 μm or less.
　正極本体では、電解液を保持するための空孔が必要であり、ある程度のサイズの空孔を確保するという観点では、正極本体を形成する粒子の平均粒径が０．１μｍ以上であることが好ましく、０．２μｍ以上であることがより好ましい。また、３、６および８番のサンプルの充電性能の結果から、正極本体を形成する粒子の平均粒径が２μｍ以下であることにより、金属空気電池の充電性能が高くなるといえる。充電性能は、粒子の平均粒径が小さくなるに従って、すなわち、反応有効面積の増大により向上するため、上記結果に基づいて、粒子の平均粒径は、０．８μｍ以下であることがより好ましいといえる。 In the positive electrode main body, holes for holding the electrolyte solution are necessary. From the viewpoint of securing holes of a certain size, the average particle diameter of the particles forming the positive electrode main body may be 0.1 μm or more. Preferably, it is 0.2 μm or more. Further, from the results of the charging performance of the Nos. 3, 6 and 8 samples, it can be said that the charging performance of the metal-air battery is enhanced when the average particle diameter of the particles forming the positive electrode body is 2 μm or less. Since the charging performance is improved as the average particle size of the particles decreases, that is, by increasing the reaction effective area, the average particle size of the particles is more preferably 0.8 μm or less based on the above results. I can say that.
　正極触媒層を形成する粒子の平均粒径Ｄ１と、正極本体を形成する粒子の平均粒径Ｄ２との比の値（Ｄ１／Ｄ２）を考えると、（Ｄ１／Ｄ２）の好ましい範囲は、１～１００であり、より好ましい範囲は、２～２０である。３、１０および１１番のサンプルの充電および放電性能の結果から、厚さ比率が１：９および９：１の場合では、５：５の場合よりも充電および放電性能が低下する。一方、７ないし９番のサンプルの充電および放電性能の結果から、厚さ比率が３：７、５：５、７：３の場合では、一定の充電および放電性能が維持される。したがって、正極触媒層の厚さは、正極本体の厚さの０．４倍（厚さ比率が３：７に相当）以上かつ２．３倍以下（厚さ比率が７：３に相当）であることが好ましい。これにより、金属空気電池において、放電および充電の双方についてある程度の性能を確保することが可能となる。 Considering the ratio value (D1 / D2) between the average particle diameter D1 of the particles forming the positive electrode catalyst layer and the average particle diameter D2 of the particles forming the positive electrode main body, the preferable range of (D1 / D2) is 1 -100, and a more preferable range is 2-20. From the results of the charge and discharge performance of the samples 3, 10 and 11, the charge and discharge performance is lower in the thickness ratios of 1: 9 and 9: 1 than in the case of 5: 5. On the other hand, from the results of the charge and discharge performance of the samples 7 to 9, constant charge and discharge performance is maintained when the thickness ratio is 3: 7, 5: 5, and 7: 3. Therefore, the thickness of the positive electrode catalyst layer is 0.4 times or more (thickness ratio corresponding to 3: 7) and 2.3 times or less (thickness ratio corresponding to 7: 3) of the thickness of the positive electrode body. Preferably there is. Thereby, in a metal air battery, it becomes possible to ensure a certain amount of performance about both discharge and charge.
　上記金属空気電池１では様々な変形が可能である。 The metal-air battery 1 can be variously modified.
　金属空気電池１において、筒状の正極２の周囲に負極３が設けられてもよい。すなわち、負極３は、正極２の内側面または外側面に対向すればよい。なお、負極３が正極２の外側面に対向する金属空気電池１では、セパレータ４１は正極本体２１の外側面に設けられる。 In the metal-air battery 1, the negative electrode 3 may be provided around the cylindrical positive electrode 2. That is, the negative electrode 3 may be opposed to the inner surface or the outer surface of the positive electrode 2. In the metal-air battery 1 in which the negative electrode 3 faces the outer surface of the positive electrode 2, the separator 41 is provided on the outer surface of the positive electrode body 21.
　金属空気電池１の設計によっては、例えば、セパレータ４１が筒状の独立した部材として準備され、外側面に正極触媒層２２が形成された正極本体２１の内部に、当該部材が挿入されてもよい。また、金属空気電池１に求められる電池性能によっては、セパレータ４１のみが正極本体２１の内側面に形成され、正極触媒層２２が省略されてもよい。金属空気電池１では、筒状の支持体である正極本体２１の内側面または外側面に多孔膜がセラミックにて形成される、すなわち、正極本体２１が、内側面または外側面において、セラミックにて形成された多孔膜を支持可能な筒状部材として設けられることにより、正極２を容易に厚くすることができ、正極２の電気抵抗を低くして、電池性能を向上することができる。デンドライトの発生が問題とならない場合等には、セパレータ４１が省略されてよい。 Depending on the design of the metal-air battery 1, for example, the separator 41 may be prepared as a cylindrical independent member, and the member may be inserted into the positive electrode body 21 in which the positive electrode catalyst layer 22 is formed on the outer surface. . Further, depending on the battery performance required for the metal-air battery 1, only the separator 41 may be formed on the inner surface of the positive electrode body 21, and the positive electrode catalyst layer 22 may be omitted. In the metal-air battery 1, a porous film is formed of ceramic on the inner side surface or the outer side surface of the positive electrode main body 21 that is a cylindrical support, that is, the positive electrode main body 21 is formed of ceramic on the inner side surface or the outer side surface. By providing the formed porous film as a cylindrical member capable of supporting, the positive electrode 2 can be easily thickened, the electric resistance of the positive electrode 2 can be lowered, and the battery performance can be improved. If the occurrence of dendrite does not matter, the separator 41 may be omitted.
　上記実施の形態および各変形例における構成は、相互に矛盾しない限り適宜組み合わされてよい。 The configurations in the above embodiment and each modification may be combined as appropriate as long as they do not contradict each other.
　発明を詳細に描写して説明したが、既述の説明は例示的であって限定的なものではない。したがって、本発明の範囲を逸脱しない限り、多数の変形や態様が可能であるといえる。 Although the invention has been described in detail, the above description is illustrative and not restrictive. Therefore, it can be said that many modifications and embodiments are possible without departing from the scope of the present invention.
　１　　金属空気電池
　２　　正極
　３　　負極
　４　　電解質層
　２１　　正極本体
　２２　　正極触媒層
　４１　　セパレータ DESCRIPTION OF SYMBOLS 1 Metal-air battery 2 Positive electrode 3 Negative electrode 4 Electrolyte layer 21 Positive electrode main body 22 Positive electrode catalyst layer 41 Separator

Claims (10)

  1. 　金属空気電池であって、
    　筒状の正極と、
    　前記正極の内側面または外側面に対向する負極と、
    　前記負極と前記正極との間に配置される電解質層と、
    を備え、
    　前記正極が、導電性セラミックにて形成された筒状の支持体である多孔質の正極本体を有し、
    　前記正極本体の内側面または外側面に多孔膜がセラミックにて形成される。     A metal-air battery,
    A cylindrical positive electrode;
    A negative electrode facing the inner or outer surface of the positive electrode;
    An electrolyte layer disposed between the negative electrode and the positive electrode;
    With
    The positive electrode has a porous positive electrode body that is a cylindrical support formed of a conductive ceramic;
    A porous film is formed of ceramic on the inner or outer surface of the positive electrode body.
  2. 　請求項１に記載の金属空気電池であって、
    　前記多孔膜が、前記正極本体の前記負極側の面に、絶縁性の前記セラミックにて形成されたセパレータである。     The metal-air battery according to claim 1,
    The porous film is a separator formed of the insulating ceramic on a surface of the positive electrode body on the negative electrode side.
  3. 　請求項２に記載の金属空気電池であって、
    　前記正極本体の厚さが、前記セパレータの厚さよりも大きい。     The metal-air battery according to claim 2,
    The positive electrode body has a thickness greater than the thickness of the separator.
  4. 　請求項１に記載の金属空気電池であって、
    　前記多孔膜が、前記正極本体の前記負極とは反対側の面に形成された正極触媒層である。     The metal-air battery according to claim 1,
    The porous membrane is a positive electrode catalyst layer formed on a surface of the positive electrode main body opposite to the negative electrode.
  5. 　請求項２または３に記載の金属空気電池であって、
    　前記正極本体の前記負極とは反対側の面に、正極触媒層であるもう１つの多孔膜がセラミックにて形成され、
    　前記多孔膜が前記正極本体の前記内側面に形成され、前記もう１つの多孔膜が前記正極本体の前記外側面に形成される。     The metal-air battery according to claim 2 or 3,
    On the surface of the positive electrode body opposite to the negative electrode, another porous film that is a positive electrode catalyst layer is formed of ceramic,
    The porous film is formed on the inner surface of the positive electrode body, and the another porous film is formed on the outer surface of the positive electrode body.
  6. 　請求項４または５に記載の金属空気電池であって、
    　前記正極触媒層の前記セラミックが前記正極本体の前記導電性セラミックと同じ結晶構造を有する。     The metal-air battery according to claim 4 or 5,
    The ceramic of the positive electrode catalyst layer has the same crystal structure as the conductive ceramic of the positive electrode body.
  7. 　請求項４ないし６のいずれかに記載の金属空気電池であって、
    　前記正極触媒層の前記セラミックが、前記正極本体の前記導電性セラミックよりも酸素還元反応に優れ、
    　前記正極本体の前記導電性セラミックが、前記正極触媒層の前記セラミックよりも酸素発生反応に優れる。     The metal-air battery according to any one of claims 4 to 6,
    The ceramic of the positive electrode catalyst layer is superior in oxygen reduction reaction than the conductive ceramic of the positive electrode body,
    The conductive ceramic of the positive electrode body is superior in oxygen generation reaction than the ceramic of the positive electrode catalyst layer.
  8. 　請求項４ないし７のいずれかに記載の金属空気電池であって、
    　前記正極本体の前記導電性セラミックの平均粒径が、０．１マイクロメートル以上かつ２マイクロメートル以下である。     The metal-air battery according to any one of claims 4 to 7,
    An average particle diameter of the conductive ceramic of the positive electrode body is 0.1 micrometer or more and 2 micrometers or less.
  9. 　請求項４ないし８のいずれかに記載の金属空気電池であって、
    　前記正極触媒層の前記セラミックの平均粒径が、１マイクロメートル以上かつ１０マイクロメートル以下である。     A metal-air battery according to any one of claims 4 to 8,
    The average particle diameter of the ceramic of the positive electrode catalyst layer is not less than 1 micrometer and not more than 10 micrometers.
  10. 　請求項４ないし９のいずれかに記載の金属空気電池であって、
    　前記正極触媒層の厚さが、前記正極本体の厚さの０．４倍以上かつ２．３倍以下である。     The metal-air battery according to any one of claims 4 to 9,
    The thickness of the positive electrode catalyst layer is not less than 0.4 times and not more than 2.3 times the thickness of the positive electrode body.
PCT/JP2015/079134 2014-11-17 2015-10-15 Metal-air battery WO2016080115A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US15/527,243 US20170338536A1 (en) 2014-11-17 2015-10-15 Metal-air battery

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2014232466 2014-11-17
JP2014-232466 2014-11-17
JP2015-068952 2015-03-30
JP2015068952A JP6596213B2 (en) 2014-11-17 2015-03-30 Metal air battery

Publications (1)

Publication Number Publication Date
WO2016080115A1 true WO2016080115A1 (en) 2016-05-26

Family

ID=56013673

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2015/079134 WO2016080115A1 (en) 2014-11-17 2015-10-15 Metal-air battery

Country Status (1)

Country Link
WO (1) WO2016080115A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112018308A (en) * 2019-05-29 2020-12-01 中国科学院宁波材料技术与工程研究所 Lithium air battery aluminum silicate ceramic fiber diaphragm, preparation method thereof and lithium air battery

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012209020A (en) * 2011-03-29 2012-10-25 Hitachi Zosen Corp Metal-air battery
JP2014137958A (en) * 2013-01-18 2014-07-28 Hitachi Zosen Corp Electrode, metal-air battery and method of manufacturing electrode

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012209020A (en) * 2011-03-29 2012-10-25 Hitachi Zosen Corp Metal-air battery
JP2014137958A (en) * 2013-01-18 2014-07-28 Hitachi Zosen Corp Electrode, metal-air battery and method of manufacturing electrode

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112018308A (en) * 2019-05-29 2020-12-01 中国科学院宁波材料技术与工程研究所 Lithium air battery aluminum silicate ceramic fiber diaphragm, preparation method thereof and lithium air battery
CN112018308B (en) * 2019-05-29 2023-01-31 中国科学院宁波材料技术与工程研究所 Preparation method and application of aluminum silicate ceramic fiber diaphragm of lithium air battery

Similar Documents

Publication Publication Date Title
Zhan et al. A reduced temperature solid oxide fuel cell with nanostructured anodes
WO2017002654A1 (en) Electrode and metal-air secondary battery
JP6588716B2 (en) Metal air battery
JP6121954B2 (en) Solid oxide fuel cell
JP2018154864A (en) High temperature steam electrolysis cell, hydrogen electrode layer therefor, and solid oxide electrochemical cell
JP6596213B2 (en) Metal air battery
JP2010238432A (en) Power generation cell of fuel battery
JP2017208197A (en) Metal air secondary battery
WO2016080115A1 (en) Metal-air battery
JP6485123B2 (en) Anode for fuel cell and single cell for fuel cell
US20200112043A1 (en) Porous solid oxide fuel cell anode with nanoporous surface and process for fabrication
RU2368983C1 (en) High-temperature electrochemical element with electrophoretically deposited hard electrolyte and method of its manufacturing
JP6259815B2 (en) Metal air battery
JP6068228B2 (en) Separator, metal-air secondary battery, and separator manufacturing method
JP6166929B2 (en) Metal-air secondary battery
JP2019207885A (en) Metal air battery
JP2006127973A (en) Fuel battery cell
JP3342621B2 (en) Solid oxide fuel cell
KR100863315B1 (en) Solid oxide fuel cell
JP2009231209A (en) Method of manufacturing fuel cell
JP2015185235A (en) Electrode and secondary battery
KR20120127848A (en) Cathode for solid oxide fuel cells and electrolysis cells, method for fabricating the same
JP2012099497A (en) Solid oxide fuel cell and solid oxide fuel cell stack
KR101573795B1 (en) Solid oxide cell comprising electrolyte film of sandwich structure with blocking layer and manufacturing method thereof
RU2522188C1 (en) Double-layer supporting cathode manufacturing method for solid oxide fuel cells

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 15860812

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 15860812

Country of ref document: EP

Kind code of ref document: A1