JP6081863B2 - How to use a metal-air secondary battery - Google Patents

Description

  The present invention relates to a method for using a metal-air secondary battery such as a zinc-air battery or a lithium-air battery.

  One of the innovative battery candidates is a metal-air secondary battery. In metal-air secondary batteries, oxygen involved in battery reaction is supplied from the air, so the space in the battery container can be used to the maximum for filling the negative electrode active material, which in principle provides a high energy density. Can be realized.

As one type of metal-air battery, a zinc-air battery using zinc as a negative electrode active material has been conventionally known. In particular, zinc-air primary batteries have already been mass-produced and are widely used as power supplies for hearing aids and the like. In a zinc-air battery, an alkaline aqueous solution such as potassium hydroxide is used as an electrolytic solution, and a separator (partition) is used to prevent a short circuit between positive and negative electrodes. At the time of discharging, as shown in the following reaction formula, O ₂ is reduced on the air electrode (positive electrode) side to generate OH ^−, while zinc is oxidized on the negative electrode to generate ZnO.
Positive electrode: O ₂ + 2H ₂ O + 4e ⁻ → 4OH ^{−
Negative: 2Zn + 4OH - → 2ZnO +} 2H 2 O + 4e -
Although an attempt was made to use this zinc-air battery as a secondary battery, the actual reaction of the negative electrode was as follows:
Negative electrode: Zn + 4OH ⁻ → Zn (OH) ₄ ²⁻ + 2e ⁻
Produces a ionic species Zn (OH) ₄ ^{2− that} is soluble in the electrolyte, which is reduced during charging and metal zinc precipitates into dendrites to form dendrites that pass through the separator and are positive electrodes There was a problem of causing a short circuit, which greatly hindered the practical application of zinc-air batteries as secondary batteries. In order to suppress the generation of dendrite in the secondary battery, an attempt to include a dendrite formation inhibitor in the electrolytic solution has been proposed (for example, Japanese Patent Application Laid-Open No. 2009-93983). )reference).

In addition, lithium-air batteries have been actively developed recently. In a normal lithium-air battery, during discharge, as shown in the following reaction formula, O ₂ is reduced on the air electrode (positive electrode) side to generate Li ₂ O, while lithium is oxidized at the negative electrode to form Li ₂ O. ⁺ Produces. The reverse reaction occurs during charging.
Positive electrode: O ₂ + 4e ⁻ + 4Li ⁺ → 2Li ₂ O
Negative electrode: Li → Li ⁺ + e ⁻
For example, Patent Document 2 (Japanese Patent Application Laid-Open No. 2010-176941) includes a negative electrode containing lithium metal, an electrolyte for the negative electrode, a solid electrolyte separator through which only lithium ions pass, an electrolyte for the air electrode, and an air electrode. A lithium-air battery provided in order is disclosed, and it has been proposed to use an organic electrolyte as an electrolyte for a negative electrode and an alkaline aqueous electrolyte as an electrolyte for an air electrode.

In recent years, as a solid electrolyte having a hydroxide ion ^{_{conductivity, M 2+ 1-x M 3+}} x (OH) 2 A n- x / n · mH 2 O becomes the general formula ^{(wherein, M 2+} is a divalent of a cation, M ³⁺ is a trivalent cation, a ^n-are known layered double hydroxide (LDH) is represented by a is) n-valent anion, direct alcohol fuel cell It has been proposed to use a layered double hydroxide film as the alkaline electrolyte film (see, for example, Patent Document 3 (International Publication No. 2010/109670)).

JP 2009-93983 A JP 2010-176941 A International Publication No. 2010/109670

  However, in any of the configurations disclosed in Patent Document 1 relating to a zinc-air battery and Patent Document 2 relating to a lithium-air battery, carbon dioxide in the air passes through the air electrode and reaches an alkaline aqueous electrolyte and reacts. The problem that the electrolytic solution deteriorates due to the formation of the alkali metal carbonate and the problem that the alkali metal carbonate closes the pores in the air electrode may occur, so that it is not suitable for long-term use. In contrast, by interposing a hydroxide ion conductive solid electrolyte between the air electrode and the electrolyte, the electrolyte and the air electrode can be effectively prevented from deteriorating and have a long life and long-term reliability. A method for realizing a highly functional air secondary battery can be considered. That is, this is a technique in which only hydroxide ions generated at the air electrode are transmitted and carbon dioxide is not transmitted by the hydroxide ion conductive solid electrolyte body.

By the way, when the hydroxide ion conductive solid electrolyte body is used as described above, the air electrode does not directly contact the electrolytic solution (aqueous solution). For this reason, in order to generate hydroxide ions (OH ⁻ ), it is necessary to supply not only oxygen in the air but also H ₂ O to the air electrode. In this respect, although the actual mechanism is not clear, the H ₂ O uses H ₂ O molecules in the crystal of the hydroxide ion conductive solid electrolyte and water vapor in the air. Although it was initially thought that this secondary battery would operate stably if there was a sufficient amount of moisture in the air, the layered double hydroxide used as a hydroxide ion conductive solid electrolyte was actually used. It has been found that the hydroxide ion (OH ⁻ ) conductivities of the samples exhibit unexpectedly different values depending on the relative humidity, that is, the water vapor concentration in the air. Similarly, the ionic conductivity was found to vary greatly depending on the temperature.

  That is, the present inventors, in hydroxide ion conductive solid electrolytes such as layered double hydroxides, when the water vapor concentration in the air and the temperature of the battery fluctuate, the ionic conductivity changes significantly. In addition, we obtained knowledge that the characteristics such as the output of the metal-air secondary battery are unexpectedly unstable. As a result, it has been found that the battery output characteristics and the like can be stabilized by controlling the temperature of the metal-air secondary battery and / or the humidity in the air supplied to the air electrode to be substantially constant.

  Accordingly, an object of the present invention is to provide a usage method for stabilizing output characteristics and the like in a metal-air secondary battery.

According to one aspect of the present invention, there is provided a method for using a metal-air secondary battery, wherein the metal-air secondary battery is in close contact with a hydroxide ion conductive solid electrolyte body and one surface side of the solid electrolyte body. An air electrode as a positive electrode provided, and a metal negative electrode provided on the other surface side of the solid electrolyte body,
There is provided a method of using a metal-air secondary battery, comprising controlling the temperature of the metal-air secondary battery and / or humidity in the air supplied to the air electrode to be substantially constant.

It is a schematic cross section which shows an example of the zinc air secondary battery which can be used for this invention. It is a conceptual diagram for demonstrating the lithium air secondary battery which can be used for this invention. It is a schematic cross section which shows an example of the lithium air secondary battery which can be used for this invention. 6 is a schematic diagram showing a measurement system used for conductivity measurement in Example 2. FIG. FIG. 5 is a diagram showing the temperature dependence of ionic conductivity measured in Example 2. It is a figure which shows the relative humidity dependence of the ionic conductivity measured in Example 2. FIG. It is a figure which shows the charging / discharging characteristic obtained by the constant current measurement in Example 2.

TECHNICAL FIELD The present invention is a method for using a metal-air secondary battery. The metal-air secondary battery used in the method of the present invention includes a hydroxide ion conductive solid electrolyte body, an air electrode as a positive electrode provided in close contact with one surface side of the solid electrolyte body, and the other surface of the solid electrolyte body. And a metal negative electrode provided on the side. Although details of such a hydroxide ion conductive solid electrolyte body and a metal-air secondary battery using the same will be described later, preferred examples of application include a zinc-air battery and a lithium-air battery. In the method of the present invention, the temperature of the metal-air secondary battery and / or the humidity in the air supplied to the air electrode are controlled to be substantially constant, preferably constant. Thereby, the output characteristics and the like of the battery can be stabilized. The details are explained as follows.

That is, as described above, when a metal-air secondary battery having the above structure is constructed using a hydroxide ion conductive solid electrolyte body, the air electrode is in contact with the hydroxide ion conductive solid electrolyte body, One side of the oxide ion conductive solid electrolyte body is in contact with air. However, according to current knowledge, the hydroxide ion (OH ⁻ ) conductivity of the layered double hydroxide used as the hydroxide ion conductive solid electrolyte body is predicted by the relative humidity, that is, the water vapor concentration in the air. Different values are shown. Similarly, the ionic conductivity varies greatly depending on the temperature. Therefore, by controlling the temperature of the metal-air secondary battery and / or the humidity in the air supplied to the air electrode to be substantially constant, preferably constant, the ionic conductivity of the hydroxide ion conductive solid electrolyte body is controlled. As a result, the output characteristics and the like of the battery can be stabilized.

  In the method of the present invention, the temperature of the metal-air secondary battery is preferably controlled to be substantially constant, more preferably controlled to be constant. Thereby, the ionic conductivity of the hydroxide ion conductive solid electrolyte body having a large temperature dependence of the ionic conductivity can be stabilized. Controlling the temperature to be substantially constant or constant means that the temperature fluctuation is suppressed to such an extent that the output characteristics of the battery are stabilized, and the temperature fluctuation width is preferably less than ± 5 ° C., more preferably ± 2.5 ° C. Less than, more preferably less than ± 1.5 ° C., ideally ± 0 ° C. The allowable range of the temperature fluctuation range can be allowed even if the temperature fluctuation range is relatively wide since the influence of the conductivity on the output is small if the set temperature is sufficiently high. In particular, when considering actual operation, control with an extremely narrow temperature fluctuation range can be disadvantageous in terms of cost because it can be disadvantageous in terms of cost by reducing the energy density by enlarging the control system. What is necessary is just to control by the moderate temperature fluctuation range. As a method for making the temperature substantially constant, any method can be adopted and is not particularly limited, but a method of storing the battery container in a container provided with a heat insulating material and a heater is preferably exemplified. Or it is good also as a structure which warms a battery container to predetermined temperature using the air warmed by the high temperature waste heat discharged | emitted from a factory, another electric power generating apparatus, etc.

  In the method of the present invention, the humidity in the air supplied to the air electrode is preferably controlled to be substantially constant, more preferably controlled to be constant. Thereby, the ionic conductivity of the hydroxide ion conductive solid electrolyte body in which the humidity dependence of the ionic conductivity is large can be stabilized. Controlling the humidity substantially constant or constant means that the humidity fluctuation is suppressed to such an extent that the output characteristics of the battery are stabilized, and the relative humidity fluctuation width is preferably less than ± 5%, more preferably ± 2.5. %, Ideally ± 0%. The allowable range of the relative humidity fluctuation range can be allowed even if the relative humidity fluctuation range is relatively wide because the influence of the conductivity on the output becomes small if the set humidity is sufficiently high. In particular, when considering actual operation, control with an extremely narrow relative humidity fluctuation range does not cause such inconvenience because the control system may be enormous and the energy density may be lowered, which may be disadvantageous in terms of cost. What is necessary is just to control by the relative humidity fluctuation range moderate. As a method for making the humidity substantially constant, any method can be adopted and it is not particularly limited. However, the air in which the humidity is adjusted to be substantially constant from the outside in a container (preferably a sealed container) containing the battery. The method of feeding in is preferably exemplified.

  Particularly preferably, both the temperature of the metal-air secondary battery and the humidity in the air that can come into contact with the air electrode are controlled to be substantially constant or constant. Thereby, the ionic conductivity of the hydroxide ion conductive solid electrolyte body can be more reliably stabilized, and as a result, the output characteristics and the like of the battery can be more reliably stabilized.

Metal-air secondary battery A metal-air secondary battery used in the method of the present invention includes a hydroxide ion conductive solid electrolyte body, an air electrode as a positive electrode provided in close contact with one surface side of the solid electrolyte body, A metal negative electrode provided on the other surface side of the solid electrolyte body. According to this configuration, as described above, various metal-air batteries having a long life and high long-term reliability can be realized. According to a preferred embodiment of the present invention, the metal negative electrode may comprise zinc or a zinc alloy, whereby a zinc-air secondary battery can be constructed. Alternatively, according to another preferred embodiment of the present invention, the metal negative electrode may comprise lithium or a lithium alloy, whereby a lithium-air secondary battery can be constructed. Typically, an alkaline electrolyte is used between the solid electrolyte body and the negative electrode. In a lithium-air secondary battery, it is preferable to use a lithium ion-containing aqueous solution as the electrolyte between the solid electrolyte body and the negative electrode. .

  A zinc-air battery and a lithium-air battery, which are preferred forms of the metal-air secondary battery, will be specifically described below.

(1) Zinc Air Secondary Battery FIG. 1 conceptually shows the configuration of a zinc air secondary battery that can be used in the present invention. A zinc-air secondary battery 10 shown in FIG. 1 includes an air electrode 12 as a positive electrode, a hydroxide ion conductive solid electrolyte body 14, a metal negative electrode 16, and an electrolytic solution. The hydroxide ion conductive solid electrolyte body 14 is provided in close contact with one surface side of the air electrode 12 and has hydroxide ion conductivity. The metal negative electrode 16 is provided on the opposite side of the hydroxide ion conductive solid electrolyte body 14 from the air electrode 12 and includes zinc or a zinc alloy. The electrolytic solution is separated from the air electrode 12 by the hydroxide ion conductive solid electrolyte body 14, and the metal negative electrode 16 is immersed in the electrolytic solution.

Thus, the zinc-air secondary battery 10 is provided with the hydroxide ion conductive solid electrolyte body 14 in close contact with one surface side of the air electrode 12. According to such a configuration, since the hydroxide ion conductive solid electrolyte body 14 is interposed between the air electrode 12 and the electrolytic solution, the hydroxide ions (OH ⁻⁾ generated at the air electrode 12 are present. ) Only through the electrolyte solution, while mixing in undesirable substances such as carbon dioxide contained in the air can be prevented. Thereby, deterioration of electrolyte solution can be prevented and a long-life zinc-air battery can be realized. At the same time, the intervention of the hydroxide ion conductive solid electrolyte body 14 prevents alkali metal ions in the electrolytic solution from moving to the air electrode 12, and precipitates made of alkali metal carbonate are present in the air electrode 12. It is also possible to avoid the problem of being generated in the pores and blocking the pores, which contributes to the improvement of long-term reliability. Further, since the hydroxide ion conductive solid electrolyte body 14 is typically composed of a dense and hard inorganic solid, a short circuit between the positive and negative electrodes due to the contact of the zinc dendrite generated during charging with the air electrode is physically performed. It is also possible to prevent this. As a result, it is possible to provide a zinc-air secondary battery having a long life and high long-term reliability.

That is, the reaction at the time of discharge in the air electrode (positive electrode) 12 and the metal negative electrode 16 in the zinc-air secondary battery 10 is as follows, and vice versa at the time of charging.
Positive electrode: O ₂ + 2H ₂ O + 4e ⁻ → 4OH ^{−
Negative: 2Zn + 4OH - → 2ZnO +} 2H 2 O + 4e -

In the zinc-air secondary battery 10, the hydroxide ion conductive solid electrolyte body 14 is provided in close contact with one surface side of the air electrode 12, so that the electrolyte is a metal of the hydroxide ion conductive solid electrolyte body 14. It exists only on the negative electrode 16 side and does not exist on the air electrode 12 side. In this case, the H _{2 O} required for the cathode reaction infiltration was H _{2 O} can be used in water can be hydroxide ion conductive solid electrolyte body in the molecular structure, moisture together in air to the cathode reaction It can also be used as the required H ₂ O. Therefore, for efficient battery operation, the battery of the present invention is preferably used in the presence of humidified air.

(1a) Hydroxide Ion Conductive Solid Electrolyte Body The hydroxide ion conductive solid electrolyte body 14 includes an inorganic solid electrolyte having hydroxide ion conductivity and is generated at the air electrode 12. Any member that can selectively pass ions through the electrolyte can be used. That is, the hydroxide ion conductive solid electrolyte body 14 prevents undesirable substances such as carbon dioxide contained in the air from entering the battery, and at the same time, alkali metal ions in the electrolyte move to the air electrode 12. To stop doing. Accordingly, it is desirable that the hydroxide ion conductive solid electrolyte body 14 is impermeable to carbon dioxide. For this reason, it is preferable that the hydroxide ion conductive inorganic solid electrolyte is a dense ceramic. In particular, since the inorganic solid electrolyte is composed of a dense and hard inorganic solid, it is possible to prevent both short-circuiting between the positive and negative electrodes due to zinc dendrite and mixing of carbon dioxide. Such a hydroxide ion conductive solid electrolyte body preferably has a relative density of 88% or more, calculated by Archimedes method, more preferably 90% or more, still more preferably 94% or more. The present invention is not limited to this as long as undesirable substances such as carbon dioxide contained in the air can be prevented from being mixed into the battery or penetrated by zinc dendrite. The hydroxide ion conductive inorganic solid electrolyte is preferably a layered double hydroxide (LDH). Such a layered double hydroxide is preferably densified by a hydrothermal solidification method. Therefore, a simple green compact that has not undergone hydrothermal solidification is not dense and is brittle in a solution, which is not preferable as the hydroxide ion conductive solid electrolyte body of the present invention. However, any solidification method can be adopted as long as a dense and hard hydroxide ion conductive solid electrolyte body can be obtained without using the hydrothermal solidification method. Thus, the hydroxide ion conductive solid electrolyte body 14 is preferably composed of a layered double hydroxide dense body. A preferable layered double hydroxide dense body and a production method thereof will be described later.

According to another preferred embodiment of the present invention, the hydroxide ion conductive inorganic solid electrolyte is NaCo ₂ O ₄ , LaFe ₃ Sr ₃ O ₁₀ , Bi ₄ Sr ₁₄ Fe ₂₄ O ₅₆ , NaLaTiO ₄ , RbLaNb ₂ O _7. , KLaNb ₂ O _7, and _{Sr 4 Co 1.6 Ti 1.4 O 8} (OH) may have at least one basic composition selected from the group consisting of ₂ · xH 2 O. These inorganic solid electrolytes are disclosed as hydroxide ion conductive solid electrolytes for fuel cells in International Publication No. 2011/108526, and a dense sintered body having the above basic composition is produced by sintering. Then, it can obtain by performing reduction | restoration and a hydrolysis process and making hydroxide ion conductivity express.

The shape of the hydroxide ion conductive solid electrolyte body 14 is not particularly limited and may be either a dense plate or a membrane, but the plate is formed to penetrate zinc dendrite, carbon dioxide. It is preferable in that it is possible to more effectively prevent the mixing of alkali metal ions and the movement of alkali metal ions to the air electrode. However, if the hydroxide ion conductive solid electrolyte body 14 is dense enough to prevent carbon dioxide contamination and migration of alkali metal ions to the air electrode, it may be formed into a film. preferable. The preferred thickness of the plate-like hydroxide ion conductive solid electrolyte body is 0.01 to 0.5 mm, more preferably 0.01 to 0.2 mm, and still more preferably 0.01 to 0.1 mm. is there. Further, the hydroxide ion conductivity of the hydroxide ion conductive solid electrolyte body is preferably as high as possible, but typically 1 × 10 ⁻⁴ to 1 × 10 ⁻¹ S / m (1 × 10 ^{− 3 to 1} mS / cm), more typically 1.0 × 10 ^{−4 to} 1.0 × 10 ⁻² S / m (1.0 × 10 ^{−3 to} 1.0 × 10 ⁻¹ mS / cm). Conductivity.

  The hydroxide ion conductive solid electrolyte body 14 is a composite of a particle group including an inorganic solid electrolyte having hydroxide ion conductivity and an auxiliary component that assists densification and hardening of the particle group. There may be. Alternatively, the hydroxide ion conductive solid electrolyte body 14 includes an open-pore porous body as a substrate and an inorganic solid electrolyte (for example, deposited and grown in the pores so as to fill the pores of the porous body) It may be a composite with a layered double hydroxide). Examples of the substance constituting the porous body include ceramics such as alumina and zirconia, and insulating substances such as a porous sheet made of a foamed resin or a fibrous substance.

  In order to hold hydroxide ions more stably on the hydroxide ion conductive solid electrolyte body 14, a porous substrate may be provided on one side or both sides of the hydroxide ion conductive solid electrolyte body 14. In the case where a porous substrate is provided on one surface of the hydroxide ion conductive solid electrolyte body 14, a method of preparing a porous substrate and depositing an inorganic solid electrolyte on the porous substrate can be considered. On the other hand, when a porous substrate is provided on both surfaces of the hydroxide ion conductive solid electrolyte body 14, densification may be performed by sandwiching the raw material powder of the inorganic solid electrolyte between the two porous substrates. Conceivable.

(1b) Air electrode (positive electrode)
The air electrode 12 is not particularly limited as long as it functions as a positive electrode in a zinc-air battery, and various air electrodes that can use oxygen as a positive electrode active material can be used. Preferred examples of the air electrode 12 include carbon-based materials having a redox catalyst function such as graphite, metals having a redox catalyst function such as platinum and nickel, perovskite oxides, manganese dioxide, nickel oxide, cobalt oxide, spinel. Examples thereof include catalyst materials such as oxides and other inorganic oxides having a redox catalyst function. The air electrode 12 is preferably a porous carbon material on which a catalyst having a redox catalyst function is supported. In this case, the catalyst material as described above is applied as a paste on the air electrode side of a hydroxide ion conductive solid electrolyte plate made of Mg-Al type layered double hydroxide (LDH) to form an air electrode. Also good. The air electrode 12 may be a porous material composed of inorganic oxide fine particles having a redox catalyst function. In that case, a hydroxide ion conductive solid electrolyte body is provided on one side of the porous material. Is preferably formed into a film. In this case, powder particles of perovskite type oxide are formed into a porous body by sintering, and Mg-Al type layered double hydroxide (LDH) is densely produced on one surface side of the porous body by a hydrothermal method or the like. A laminated structure of an air electrode and a hydroxide ion conductive solid electrolyte body may be formed. The air electrode 12 may contain a conductive material. The conductive material is not particularly limited as long as it is a conductive material. Preferred examples include carbon blacks such as ketjen black, acetylene black, channel black, furnace black, lamp black, and thermal black, and flaky graphite. Such as natural graphite, artificial graphite, graphite such as expanded graphite, conductive fibers such as carbon fiber, metal fiber, metal powders such as copper, silver, nickel, and aluminum, organic conductive materials such as polyphenylene derivatives, and Any mixtures of these may be mentioned.

  The air electrode 12 may contain a binder. The binder may be a thermoplastic resin or a thermosetting resin and is not particularly limited. Preferred examples include polyethylene, polypropylene, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), styrene butadiene rubber, and tetrafluoro. Ethylene-hexafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), vinylidene fluoride-hexafluoropropylene copolymer, fluorine Vinylidene fluoride-chlorotrifluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer (ETFE resin), polychlorotrifluoroethylene (PCTFE), vinylidene fluoride-pentafluoropropyl Pyrene copolymer, propylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer (ECTFE), vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluoride-perfluoromethyl vinyl ether -Tetrafluoroethylene copolymers, ethylene-acrylic acid copolymers, and any mixtures thereof.

The air electrode 12 is preferably a mixture or composite of a hydroxide ion conductive solid electrolyte body 14 and a substance made of the same hydroxide ion conductive solid electrolyte. With such a configuration, the surface area of the hydroxide ion conductive solid electrolyte body is increased, and OH ⁻ ions generated by the positive electrode reaction can be moved more effectively.

  The air electrode 12 may include a positive electrode current collector 18 on the surface opposite to the hydroxide ion conductive solid electrolyte body 14. In this case, the positive electrode current collector 18 preferably has air permeability so that air is supplied to the air electrode 12. Preferable examples of the positive electrode current collector include metal plates or metal meshes such as stainless steel, copper, and nickel, carbon paper, and oxide conductors. Stainless steel wire mesh is particularly preferable in terms of corrosion resistance and air permeability.

(1c) Metal Negative Electrode The metal negative electrode 16 comprises zinc or a zinc alloy that functions as a negative electrode active material. The metal negative electrode 16 may have any shape or form such as a particle shape, a plate shape, or a gel shape, but a particle shape or a gel shape is preferable in terms of reaction rate. As the particulate metal negative electrode, those having a particle diameter of 30 to 350 μm can be preferably used. As the gel-like metal negative electrode, it is preferable to use a gel-free metal alloy powder having a particle diameter of 100 to 300 μm, an alkaline electrolyte and a thickener (gelator) mixed and stirred. it can.

  The zinc alloy can be a hatched or non-hatched alloy such as magnesium, aluminum, lithium, bismuth, indium, lead, etc., and its content is not particularly limited as long as desired performance can be secured as a negative electrode active material. . Preferred zinc alloys are anhydrous silver and lead-free zinc-free zinc alloys, more preferably those containing aluminum, bismuth, indium or combinations thereof. More preferably, a zinc-free zinc alloy containing 50 to 1000 ppm of bismuth, 100 to 1000 ppm of indium and 10 to 100 ppm of aluminum and / or calcium, particularly preferably 100 to 500 ppm of bismuth, 300 to 700 ppm of indium, Contains 20 to 50 ppm of aluminum and / or calcium.

  The metal negative electrode 16 may be carried on a negative electrode current collector. Preferable examples of the negative electrode current collector include metal plates or metal meshes such as stainless steel, copper, and nickel, carbon paper, and oxide conductors.

(1d) Electrolytic Solution As the electrolytic solution, various electrolytic solutions generally used for zinc-air batteries can be used. Examples of the electrolyte include alkali metal hydroxide aqueous solutions such as potassium hydroxide aqueous solution and sodium hydroxide aqueous solution, aqueous solutions containing zinc chloride and zinc perchlorate, non-aqueous solvents containing zinc perchlorate, zinc bis (tri Non-aqueous solvents containing fluoromethylsulfonyl) imide are exemplified. Among them, an alkali metal hydroxide aqueous solution, particularly a potassium hydroxide aqueous solution is preferable, and a potassium hydroxide aqueous solution containing 3 to 50% by weight (for example, 30 to 45% by weight) of potassium hydroxide is more preferable.

(1e) Battery Container The air electrode 12, the hydroxide ion conductive solid electrolyte body 14, the metal negative electrode 16, and the electrolytic solution can be accommodated in the battery container 20. The battery container 20 preferably has an air hole 20a for allowing the air electrode 12 to come into contact with external air. The material, shape, and structure of the battery container are not particularly limited, but it is desirable that the battery container be configured so that air (particularly carbon dioxide) is not mixed into the electrolytic solution and the electrolytic solution does not leak.

  The battery container 20 shown in FIG. 1 includes a positive electrode container 22 that houses at least the air electrode 12 and a negative electrode container 24 that houses at least the metal negative electrode 16 and an electrolyte. The positive electrode container 22 is provided with an air hole 20 a so that air that has passed through the air-collecting current collector 18 can reach the air electrode 12. The positive electrode container 22 is fitted to the negative electrode container 24 via the gaskets 26 and 28, thereby ensuring the hermeticity in the battery container 20. Specifically, the positive electrode gasket 26 is disposed along the inner peripheral edge of the positive electrode container 22, and the total thickness of the air electrode 12 and the positive electrode current collector 18 is the thickness of the positive electrode gasket 26 inside the positive electrode gasket 26. It is arranged to be the same. A negative electrode gasket 28 is disposed on the upper edge of the negative electrode container 24 filled with the metal negative electrode 16 and the electrolyte. The inner diameter of the positive electrode container 22 is designed to be larger than the inner diameter of the negative electrode container 24, so that the positive electrode container 22 in which the gasket 26 is disposed is connected to the negative electrode container 24 in which the gasket 28 is disposed in the gaskets 26, 28. The hydroxide ion conductive solid electrolyte body 14 is sandwiched between them. The material, shape and structure of the gaskets 26 and 28 are not particularly limited as long as the airtightness and the watertightness can be ensured. However, the gaskets 26 and 28 are preferably made of an insulating material such as nylon. According to such a battery container 20, air components (particularly carbon dioxide) can reliably enter the electrolytic solution in the negative electrode container 24 through the hydroxide ion conductive solid electrolyte body 14 and the gaskets 26 and 28. Can be blocked. The procedure for fitting the positive electrode container 22 and the negative electrode container 24 is not particularly limited, and the negative electrode container 28 filled with the metal negative electrode 16 and the electrolytic solution is filled with the negative electrode gasket 28, the hydroxide ion conductive solid electrolyte body 14, and the air. The electrode 12, the positive electrode current collector 18 and the positive electrode gasket 26 may be appropriately disposed, and the positive electrode container 20 may be finally covered. Alternatively, the air electrode 12, the positive electrode current collector 18 and the positive electrode gasket 26 are incorporated in advance. The prepared positive electrode container 22 is prepared, and is combined with the negative electrode container 24 filled with the metal negative electrode 16 and the electrolyte and provided with the negative electrode gasket 28 so as to sandwich the hydroxide ion conductive solid electrolyte body 14 therebetween. May be.

  The zinc-air secondary battery that can be used in the present invention can have any shape, and can be, for example, a coin type, a button type, a sheet type, a laminated type, a cylindrical type, a flat type, a rectangular type, or the like. Moreover, it is applicable not only to a small secondary battery but also to a large secondary battery used for an electric vehicle or the like.

  The zinc-air secondary battery that can be used in the present invention may further include a positive electrode exclusively for charging (see, for example, JP 2010-176941 A). By providing a positive electrode for charging, even if the hydroxide ion conductivity of the hydroxide ion conductive solid electrolyte body is low, it is possible to use the positive electrode for charging without using it at the time of charging. It can be done at high speed. In addition, generation of oxygen at the air electrode during charging can be avoided to prevent corrosion and deterioration of the air electrode. Preferable examples of the positive electrode for charging include carbon or metal titanium mesh.

(2) Lithium Air Secondary Battery FIG. 2 conceptually shows the configuration of a lithium air secondary battery that can be used in the present invention. A lithium air secondary battery 30 shown in FIG. 2 includes an air electrode 32 as a positive electrode, a hydroxide ion conductive solid electrolyte body 34, a separator 36, a negative electrode 38, and an alkaline electrolyte 40. The hydroxide ion conductive solid electrolyte body 34 is provided in close contact with one surface side of the air electrode 32 and has hydroxide ion conductivity. The separator 36 is provided apart from the hydroxide ion conductive solid electrolyte body 34 and is made of a lithium ion conductive inorganic solid electrolyte. The negative electrode 38 is provided so as to be able to exchange lithium ions with the separator 36 and includes lithium. The alkaline electrolyte 40 is filled between the hydroxide ion conductive solid electrolyte body 34 and the separator 36.

Thus, the lithium air secondary battery 30 is provided with the hydroxide ion conductive solid electrolyte body 34 in close contact with one surface of the air electrode 32. According to such a configuration, since the hydroxide ion conductive solid electrolyte body 34 is interposed between the air electrode 32 and the alkaline electrolyte 40, hydroxide ions ( While only OH ⁻ ) is allowed to pass through the alkaline electrolyte 40, it is possible to prevent mixing of undesirable substances such as carbon dioxide contained in the air. Thereby, deterioration of alkaline electrolyte can be prevented and a long-life lithium-air battery can be realized. At the same time, by interposing the hydroxide ion conductive solid electrolyte body 34, alkali metal ions (for example, Li ⁺ ) in the alkaline electrolyte 40 are prevented from moving to the air electrode 32, and alkali metal hydroxide (for example, The problem that (LiOH) precipitates are generated in the pores in the air electrode 32 and block the pores can also be avoided, which contributes to the improvement of long-term reliability. Further, as the separator 36 that separates the alkaline electrolyte 40 and the negative electrode 38, by using a lithium ion conductive solid electrolyte that is excellent in denseness, leakage of the alkaline electrolyte 40 and hydroxide ions contained therein from the separator, In addition, the deterioration of the negative electrode due to the reaction between the alkaline electrolyte or hydroxide ions and the negative electrode 38 can be effectively prevented. As a result, it is possible to provide a lithium-air secondary battery that has a long life and high long-term reliability.

That is, the reaction during discharge in the air electrode (positive electrode) 32, the electrolytic solution 40, and the negative electrode 38 in the lithium air secondary battery 30 is as follows, and vice versa during charging.
Positive electrode: 2H ₂ O + O ₂ + 4e ⁻ → 4OH ⁻
Electrolyte: Li ⁺ + OH ⁻ → LiOH
Negative electrode: Li → Li ⁺ + e ⁻

In the lithium air secondary battery 30, the hydroxide ion conductive solid electrolyte body 34 is provided in close contact with the one surface side of the air electrode 32, so the alkaline electrolyte 40 is used as the hydroxide ion conductive solid electrolyte body 34. It exists only on the negative electrode 38 side, and does not exist on the air electrode 32 side. In this case, the H _{2 O} required for the cathode reaction infiltration was H _{2 O} can be used in water can be hydroxide ion conductive solid electrolyte body in the molecular structure, moisture together in air to the cathode reaction It can also be used as the required H ₂ O. Therefore, for efficient battery operation, the battery of the present invention is preferably used in the presence of humidified air.

(2a) Air electrode (positive electrode)
The air electrode 32 is not particularly limited as long as it functions as a positive electrode in a lithium-air battery, and various air electrodes that can use oxygen as a positive electrode active material can be used. Preferred examples of the air electrode 32 include carbon-based materials having a redox catalyst function such as graphite, metals having a redox catalyst function such as platinum and nickel, perovskite oxides, manganese dioxide, nickel oxide, cobalt oxide, spinel. Examples thereof include catalyst materials such as oxides and other inorganic oxides having a redox catalyst function. The air electrode 32 is preferably a porous carbon material on which a catalyst having a redox catalyst function is supported. In this case, the catalyst material as described above is applied as a paste on the air electrode side of a hydroxide ion conductive solid electrolyte plate made of Mg-Al type layered double hydroxide (LDH) to form an air electrode. Also good. The air electrode 32 may be a porous material composed of inorganic oxide fine particles having a redox catalyst function. In that case, a hydroxide ion conductive solid electrolyte is provided on one side of the porous material. Is preferably formed into a film. In this case, powder particles of perovskite type oxide are formed into a porous body by sintering, and Mg-Al type layered double hydroxide (LDH) is densely produced on one surface side of the porous body by a hydrothermal method or the like. A laminated structure of an air electrode and a hydroxide ion conductive solid electrolyte body may be formed. The air electrode 32 may contain a conductive material. The conductive material is not particularly limited as long as it is a conductive material. Preferred examples include carbon blacks such as ketjen black, acetylene black, channel black, furnace black, lamp black, and thermal black, and flaky graphite. Such as natural graphite, artificial graphite, graphite such as expanded graphite, conductive fibers such as carbon fiber, metal fiber, metal powders such as copper, silver, nickel, and aluminum, organic conductive materials such as polyphenylene derivatives, and Any mixtures of these may be mentioned.

  The air electrode 32 may contain a binder. The binder may be a thermoplastic resin or a thermosetting resin and is not particularly limited. Preferred examples include polyethylene, polypropylene, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), styrene butadiene rubber, and tetrafluoro. Ethylene-hexafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), vinylidene fluoride-hexafluoropropylene copolymer, fluorine Vinylidene fluoride-chlorotrifluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer (ETFE resin), polychlorotrifluoroethylene (PCTFE), vinylidene fluoride-pentafluoropropyl Pyrene copolymer, propylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer (ECTFE), vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluoride-perfluoromethyl vinyl ether -Tetrafluoroethylene copolymers, ethylene-acrylic acid copolymers, and any mixtures thereof.

The air electrode 32 is preferably a mixture or composite of a hydroxide ion conductive solid electrolyte body 34 and a substance made of the same hydroxide ion conductive solid electrolyte. With such a configuration, the surface area of the hydroxide ion conductive solid electrolyte body is increased, and OH ⁻ ions generated by the positive electrode reaction can be moved more effectively.

  The air electrode 32 may include a positive electrode current collector on the surface opposite to the hydroxide ion conductive solid electrolyte body 34. In this case, the positive electrode current collector preferably has air permeability so that air is supplied to the air electrode 12. Preferable examples of the positive electrode current collector include metal plates or metal meshes such as stainless steel, copper, and nickel, carbon paper, and oxide conductors. Stainless steel wire mesh is particularly preferable in terms of corrosion resistance and air permeability.

(2b) Hydroxide Ion Conductive Solid Electrolyte Body The hydroxide ion conductive solid electrolyte body 34 is composed of a hydroxide ion conductive inorganic solid electrolyte, and alkaline electrolyzes hydroxide ions generated at the air electrode 32. Any member that can be selectively passed through the liquid 40 can be used. That is, the hydroxide ion conductive solid electrolyte body 34 prevents undesirable substances such as carbon dioxide contained in the air from entering the battery, and at the same time, lithium ions in the alkaline electrolyte 40 reach the air electrode 32. Stop moving. Therefore, it is desirable that the hydroxide ion conductive solid electrolyte body 34 is impermeable to carbon dioxide. For this reason, it is preferable that the hydroxide ion conductive inorganic solid electrolyte is a dense ceramic. Such a dense hydroxide ion conductive solid electrolyte body preferably has a relative density of 88% or more, more preferably 90% or more, and still more preferably 94% or more, calculated by the Archimedes method. However, the present invention is not limited to this as long as undesirable substances such as carbon dioxide contained in the air can be prevented from entering the battery. The hydroxide ion conductive inorganic solid electrolyte is preferably a layered double hydroxide (LDH). Such a layered double hydroxide is preferably densified by a hydrothermal solidification method. Therefore, a simple green compact that has not undergone hydrothermal solidification is not dense and is brittle in a solution, which is not preferable as the hydroxide ion conductive solid electrolyte body of the present invention. However, any solidification method can be adopted as long as a dense and hard hydroxide ion conductive solid electrolyte body can be obtained without using the hydrothermal solidification method. Thus, the hydroxide ion conductive solid electrolyte body 34 is preferably made of a layered double hydroxide dense body. A preferable layered double hydroxide dense body and a production method thereof will be described later.

According to another preferred embodiment of the present invention, the hydroxide ion conductive inorganic solid electrolyte is NaCo ₂ O ₄ , LaFe ₃ Sr ₃ O ₁₀ , Bi ₄ Sr ₁₄ Fe ₂₄ O ₅₆ , NaLaTiO ₄ , RbLaNb ₂ O _7. , KLaNb ₂ O _7, and _{Sr 4 Co 1.6 Ti 1.4 O 8} (OH) may have at least one basic composition selected from the group consisting of ₂ · xH 2 O. These inorganic solid electrolytes are disclosed as hydroxide ion conductive solid electrolytes for fuel cells in International Publication No. 2011/108526, and a dense sintered body having the above basic composition is produced by sintering. Then, it can obtain by performing reduction | restoration and a hydrolysis process and making hydroxide ion conductivity express.

The shape of the hydroxide ion conductive solid electrolyte body 34 is not particularly limited, and may be either a dense plate shape or a membrane shape. However, the plate shape is formed by mixing carbon dioxide and lithium ions. It is preferable in that the movement to the air electrode can be more effectively prevented. However, it is also preferable that the hydroxide ion conductive solid electrolyte body 14 is formed in a film form so long as it has a density sufficient to sufficiently prevent the mixing of carbon dioxide and the movement of Li ions to the air electrode. . The preferred thickness of the plate-like hydroxide ion conductive solid electrolyte body is 0.01 to 0.5 mm, more preferably 0.01 to 0.2 mm, and still more preferably 0.01 to 0.1 mm. is there. Further, the hydroxide ion conductivity of the hydroxide ion conductive solid electrolyte body is preferably as high as possible, but typically 1 × 10 ⁻⁴ to 1 × 10 ⁻¹ S / m (1 × 10 ^{− 3 to 1} mS / cm), more typically 1.0 × 10 ^{−4 to} 1.0 × 10 ⁻² S / m (1.0 × 10 ^{−3 to} 1.0 × 10 ⁻¹ mS / cm). Conductivity.

  The hydroxide ion conductive solid electrolyte body 34 is a composite of a particle group including an inorganic solid electrolyte having hydroxide ion conductivity and an auxiliary component that assists densification and hardening of the particle group. There may be. Alternatively, the hydroxide ion conductive solid electrolyte body 34 includes an open-pore porous body as a substrate and an inorganic solid electrolyte (for example, deposited and grown in the pores so as to fill the pores of the porous body) It may be a composite with a layered double hydroxide). Examples of the substance constituting the porous body include ceramics such as alumina and zirconia, and insulating substances such as a porous sheet made of a foamed resin or a fibrous substance.

  In order to hold hydroxide ions more stably on the hydroxide ion conductive solid electrolyte body 34, a porous substrate may be provided on one side or both sides of the hydroxide ion conductive solid electrolyte body 34. In the case of providing a porous substrate on one side of the hydroxide ion conductive solid electrolyte body 34, a method of preparing a porous substrate and depositing an inorganic solid electrolyte on the porous substrate can be considered. On the other hand, when a porous substrate is provided on both surfaces of the hydroxide ion conductive solid electrolyte body 34, densification may be performed by sandwiching the raw material powder of the inorganic solid electrolyte between the two porous substrates. Conceivable.

(2c) Separator The separator 36 is made of a lithium ion conductive inorganic solid electrolyte, and separates the alkaline electrolyte 40 and the negative electrode 38 so that the alkaline electrolyte 40 and hydroxide ions are in direct contact with the negative electrode 38. It can prevent reacting. Therefore, it is desirable that the inorganic solid electrolyte is a dense ceramic that selectively allows lithium ions to pass therethrough and does not allow alkaline electrolytes, hydroxide ions, and the like to pass therethrough. In addition, by making the inorganic solid electrolyte harder than metallic lithium, even if lithium dendrite grows on the negative electrode during charging, it can be reliably prevented by the separator 38 and a short circuit between the positive and negative electrodes due to lithium dendrite can be avoided. It is. For this reason, the organic solid electrolyte separator is not used in the present invention. The inorganic solid electrolyte is desirably dense because it leads to deterioration of the negative electrode when there is a communication hole through which an alkaline electrolyte, hydroxide ions, and the like pass. For example, the inorganic solid electrolyte preferably has a relative density of 90% or more. Preferably, it is 95% or more, more preferably 99% or more. Such a high relative density can be realized by appropriately controlling the particle size, sintering temperature, and the like of the raw material powder of the inorganic solid electrolyte. The relative density can be measured by the Archimedes method. The inorganic solid electrolyte preferably has a lithium ion conductivity of 10 ⁻⁵ S / cm or more, and more preferably has a lithium ion conductivity of 10 ⁻⁴ S / cm or more.

Preferable examples of the lithium ion conductive inorganic solid electrolyte include at least one selected from the group consisting of garnet-based ceramic materials, nitride-based ceramic materials, perovskite-based ceramic materials, and phosphate-based ceramic materials. Examples of garnet ceramic material, Li-La-Zr-O-based material _{(specifically,} such as _{Li 7 La 3 Zr 2 O 12} ), the Li-La-Ta-O-based material (specifically, Li ₇ La ₃ Ta ₂ O ₁₂ ) can be used, and those described in JP 2011-051800 A, JP 2011-073962 A, and JP 2011-073963 A can also be used. Examples of nitride ceramic materials include Li ₃ N, LiPON, and the like. Examples of the perovskite-based ceramic material include Li—La—Ti—O based materials (specifically, LiLa _1-x Ti _x O ₃ (0.04 ≦ x ≦ 0.14) and the like). Examples of phosphoric acid-based ceramic materials include Li-Al-Ti-PO, Li-Al-Ge-PO, and Li-Al-Ti-Si-PO (specifically, Li _{1 + x + y al x Ti 2-x Si y} P 3-y O 12 (0 ≦ x ≦ 0.4,0 <y ≦ 0.6) , and the like).

A particularly preferred lithium ion conductive inorganic solid electrolyte is a garnet-based ceramic material in that no reaction occurs even when it is in direct contact with negative electrode lithium. In particular, an oxide sintered body having a garnet type or a garnet type-like crystal structure containing Li, La, Zr and O is excellent in sinterability and easily densified, and has high ionic conductivity. Therefore, it is preferable. A garnet-type or garnet-like crystal structure of this type of composition is called an LLZ crystal structure, and is referred to as an X-ray diffraction file No. of CSD (Cambridge Structural Database). It has an XRD pattern similar to 422259 (Li ₇ La ₃ Zr ₂ O ₁₂ ). In addition, No. Compared to 422259, the constituent elements are different and the Li concentration in the ceramics may be different, so the diffraction angle and the diffraction intensity ratio may be different. The molar ratio Li / La of Li to La is preferably 2.0 or more and 2.5 or less, and the molar ratio Zr / La to La is preferably 0.5 or more and 0.67 or less. This garnet-type or garnet-like crystal structure may further comprise Nb and / or Ta. That is, by replacing a part of Zr of LLZ with one or both of Nb and Ta, the conductivity can be improved as compared with that before the substitution. The substitution amount (molar ratio) of Zr with Nb and / or Ta is preferably set such that the molar ratio of (Nb + Ta) / La is 0.03 or more and 0.20 or less. The garnet-based oxide sintered body preferably further contains Al and / or Mg, and these elements may exist in the crystal lattice or may exist in other than the crystal lattice. The addition amount of Al is preferably 0.01 to 1% by mass of the sintered body, and the molar ratio Al / La to La is preferably 0.008 to 0.12. The addition amount of Mg is preferably 0.01 to 1% by mass or more, and more preferably 0.05 to 0.30% by mass. It is preferable that the molar ratio Mg / La of Mg to La is 0.0016 to 0.07.

(2d) Negative electrode The negative electrode 38 is configured to include lithium, and is not particularly limited as long as lithium is oxidized into lithium ions at the negative electrode at the time of discharge, and includes metal lithium, a lithium alloy, a lithium compound, and the like. Can. Lithium is excellent as a negative electrode material in that it has a higher theoretical voltage and electrochemical equivalent than other metal elements, while dendrite may grow during charging. However, according to the present invention, the inorganic solid electrolyte separator 36 prevents the dendrite from penetrating, thereby avoiding a short circuit between the positive and negative electrodes. Preferable examples of the material constituting the negative electrode 38 include metallic lithium, lithium alloy, lithium compound, and the like. Examples of the lithium alloy include lithium aluminum, lithium silicon, lithium indium, lithium tin, and the like. Examples of these include lithium nitride and lithium carbon, but metallic lithium is more preferable from the viewpoint of large capacity and cycle stability.

  The negative electrode 38 may include a negative electrode current collector. Preferable examples of the negative electrode current collector include metal plates such as stainless steel, copper, nickel, platinum, and noble metals, metal mesh, carbon paper, and oxide conductors.

  The arrangement of the negative electrode 38 is not particularly limited as long as it is provided so as to be able to exchange lithium ions with the separator. Therefore, the negative electrode 38 may be in direct contact with the separator 36 or may be configured to be in indirect contact with the nonaqueous electrolyte solution.

(2e) Alkaline electrolyte 40 The alkaline electrolyte 40 is an alkaline aqueous electrolyte. As the alkaline electrolyte 40, a lithium ion-containing aqueous solution is preferable from the viewpoint of chargeability, but it is sufficient that lithium ions are supplied from the negative electrode 38 at the time of discharging. While lithium ions in the alkaline electrolyte are involved in the negative electrode reaction, hydroxide ions in the alkaline electrolyte are involved in the positive electrode reaction. Preferable examples of the alkaline electrolyte include those obtained by dissolving lithium hydroxide in water or an aqueous solvent, and particularly preferably an aqueous lithium hydroxide solution. The alkaline electrolyte may contain a lithium halide. Preferred examples of the lithium halide include lithium fluoride (LiF), lithium chloride (LiCl), lithium bromide (LiBr), and lithium iodide (LiI). ) And the like.

  In order to increase the charge capacity, the alkaline electrolyte 40 may be premixed with a powder such as lithium hydroxide monohydrate as a discharge product. This is particularly true when a battery is constructed in a discharged state. It will be advantageous. That is, as the charging progresses, the lithium ion concentration and hydroxide ion concentration in the electrolytic solution should decrease, and the lithium hydroxide monohydrate powder dissolves in the electrolytic solution, so that lithium ions and hydroxide ions are dissolved. Newly supplied to the electrolyte.

  In order to prevent leakage of the electrolytic solution, the electrolytic solution may be gelled. As the gelling agent, it is desirable to use a polymer that swells by absorbing the solvent of the electrolytic solution, and polymers such as polyethylene oxide, polyvinyl alcohol, and polyacrylamide, and starch are used.

(2f) Battery container The air electrode 32, the hydroxide ion conductive solid electrolyte body 34, the alkaline electrolyte 40, the separator 36, and the negative electrode 38 can be accommodated in the battery container. This container preferably has an air hole for allowing the air electrode 32 to come into contact with external air. The material, shape, and structure of the battery container are not particularly limited, but it is desirable that the battery container be configured so that air (particularly carbon dioxide) is not mixed into the electrolytic solution and the electrolytic solution does not leak.

  The battery container preferably includes a positive electrode container and a negative electrode container that can be fitted to each other via a gasket. In addition, a conductive buffer material is interposed between the inner wall of the battery container (particularly the negative electrode container) and the negative electrode, so that the negative electrode 38 can be connected to the battery container or the negative electrode terminal regardless of variations in the thickness of the negative electrode due to charge / discharge. It is preferable to always keep the structure. That is, since the thickness of the conductive buffer material can be elastically changed, the connection between the negative electrode 38 and the battery container (particularly the negative electrode container) is always maintained. Preferable examples of the conductive buffer material include carbon felt, a web made of stainless steel metal fibers, and the like.

  A lithium air secondary battery according to this embodiment is shown in FIG. The lithium-air secondary battery 50 shown in the figure includes a positive electrode container 62 that houses at least the air electrode 52 and a negative electrode container 64 provided on the negative electrode 58 side. The positive electrode container 62 is provided with an air hole 62 a so that air can reach the air electrode 52. The positive electrode container 62 is fitted into the negative electrode container 64 through the gaskets 66 and 68 and the separator 56 therebetween, thereby ensuring the hermeticity in the battery container. Specifically, the air electrode 52 and the hydroxide ion conductive solid electrolyte body 54 are sequentially stacked on the bottom of the positive electrode container 62, and the inner periphery of the positive electrode container 62 is placed on the hydroxide ion conductive solid electrolyte body 54. A positive electrode gasket 66 is disposed along the positive electrode gasket 66 and the space formed by the positive electrode gasket 66 and the hydroxide ion conductive solid electrolyte body 54 is filled with the electrolytic solution 60 so as to be at the same height as the upper end of the positive electrode gasket 66. Is done. The separator 56 is provided so as to contain the electrolytic solution 60 in a space formed by the positive electrode gasket 66 and the hydroxide ion conductive solid electrolyte body 34 while being in contact with the positive electrode gasket 66. A negative electrode 68 and a conductive buffer material 70 are laminated on the central portion on the separator 56, while a positive electrode gasket 68 is disposed along the inner peripheral edge of the positive electrode container 42 on the separator 56.

The lithium air secondary battery 50 may be constructed in a discharged state or in a charged state. That is, in the case where the battery is constructed in a discharged state, the negative electrode 58 may be formed of only the negative electrode current collector, and metallic lithium may be deposited during charging to provide a function as a negative electrode.
On the other hand, when the battery is constructed in the end-of-charge state, the negative electrode 58 may be configured by laminating metallic lithium and a negative electrode current collector on the separator 56. The outer diameter of the negative electrode container 64 is designed to be smaller than the inner diameter of the positive electrode container 62, and is fitted to the positive electrode container 62 via a negative electrode gasket 68 disposed along the inner peripheral edge of the positive electrode container 62. As described above, the lithium-air secondary battery 50 of this embodiment includes the air electrode 52, the hydroxide ion conductive solid electrolyte body 54, the electrolytic solution 60, the separator 56, the negative electrode 58, and the conductive buffer material 70, the positive electrode container 62, and It has a configuration in which it is sandwiched by the negative electrode container 64 via gaskets 66 and 68, thereby ensuring the airtightness and watertightness of the portions other than the air holes 52a. Therefore, the material, shape and structure of the gaskets 66 and 68 are not particularly limited as long as the airtightness and watertightness can be ensured, but the gaskets 66 and 68 are preferably made of an insulating material such as nylon. According to such a lithium-air secondary battery 50, air components (particularly carbon dioxide) enter the inside of the battery, in particular, the electrolytic solution through the hydroxide ion conductive solid electrolyte body 54 and the gaskets 66 and 68. It can be reliably prevented.

  The lithium air secondary battery that can be used in the present invention can have any shape, and can be, for example, a coin type, a button type, a sheet type, a laminated type, a cylindrical type, a flat type, a rectangular type, or the like. Moreover, it is applicable not only to a small secondary battery but also to a large secondary battery used for an electric vehicle or the like.

  The lithium air secondary battery that can be used in the present invention may further include a positive electrode exclusively for charging (see, for example, JP 2010-176941 A). By providing a positive electrode for charging, even if the hydroxide ion conductivity of the hydroxide ion conductive solid electrolyte body is low, it is possible to use the positive electrode for charging without using it at the time of charging. It can be done at high speed. In addition, generation of oxygen at the air electrode during charging can be avoided to prevent corrosion and deterioration of the air electrode. Preferable examples of the positive electrode for charging include carbon or metal titanium mesh.

Layered double hydroxide dense body and method for producing the same As described above, it is preferable to use a layered double hydroxide dense body as the hydroxide ion conductive solid electrolyte body in the metal-air secondary battery usable in the present invention. . Preferred layered double hydroxide dense body has the general ^{_{formula: M 2+ 1-x M 3+}} x (OH) in _{2 A n- x / n · mH} 2 O ( ^{wherein, M 2+} is a divalent least one or more positive ^{ion, M 3+} is at least one or more trivalent ^cations, layered ^{a n-} is an n-valent anion, n is represented by an integer of 1 or more, x is 0.1 to 0.4) It contains a double hydroxide as the main phase, and preferably consists essentially of (or consists only of) the above layered double hydroxide.

In the above general formula, M ²⁺ may be any divalent cation, and preferred examples include Mg ²⁺ , Ca ²⁺ and Zn ²⁺ , and more preferably Mg ²⁺ . M ³⁺ may be any trivalent cation, but preferred examples include Al ³⁺ or Cr ³⁺ , and more preferred is Al ³⁺ . A ^n- may be any anion, preferred examples OH ^- and _CO ^{3 2-} and the like. Accordingly, the general formula is at least ^{M 2+} is ^{Mg 2+,} include ^{M 3+} is ^{Al 3+, A n-is} OH ^- and / or _CO preferably contains ^{3 2-.} n is an integer of 1 or more, preferably 1 or 2. x is 0.1 to 0.4, preferably 0.2 to 0.35.

  As described above, the layered double hydroxide dense body preferably has a relative density of 88% or more, more preferably 90% or more, and further preferably 94% or more. Therefore, it is preferable that the layered double hydroxide dense body does not substantially contain cracks, and more preferably does not contain any cracks.

  The dense layered double hydroxide is preferably composed of layered double hydroxide particles in which the main phase of the layered double hydroxide does not show a clear endothermic peak at 300 ° C. or lower in differential thermal analysis. That is, a clear endothermic peak observed mainly in the vicinity of 200 ° C. in differential thermal analysis is said to be due to desorption of interlayer water, and there is a large structural change such as a sudden change in interlayer distance. This is because the possibility that the stable temperature region is narrow is estimated.

  Although the layered double hydroxide dense body may be produced by any method, one embodiment of a preferable production method will be described below. In this production method, a raw material powder of a layered double hydroxide represented by hydrotalcite is molded and fired to obtain an oxide fired body, which is regenerated into a layered double hydroxide, and then excess water is removed. Is done. According to this method, a high-quality layered double hydroxide dense body having a relative density of 88% or more can be provided and produced easily and stably.

(1) as prepared raw material powder of the raw material powder, the general ^{_{formula: M 2+ 1-x M 3+}} x (OH) 2 A n- x / n · mH 2 O ( ^{wherein, M 2+} is a divalent cation, M ³⁺ is a trivalent ^{cation, a n-n-valent} anion, n represents an integer of 1 or more, x is a layered double hydroxide represented by a is) 0.1 to 0.4 powder Prepare. In the above general formula, M ²⁺ may be any divalent cation, and preferred examples include Mg ²⁺ , Ca ²⁺ and Zn ²⁺ , and more preferably Mg ²⁺ . M ³⁺ may be any trivalent cation, but preferred examples include Al ³⁺ or Cr ³⁺ , and more preferred is Al ³⁺ . A ^n- may be any anion, preferred examples OH ^- and _CO ^{3 2-} and the like. Accordingly, the general formula is at least ^{M 2+} is ^{Mg 2+,} include ^{M 3+} is ^{Al 3+, A n-is} OH ^- and / or _CO preferably contains ^{3 2-.} n is an integer of 1 or more, preferably 1 or 2. x is 0.1 to 0.4, preferably 0.2 to 0.35. Such a raw material powder may be a commercially available layered double hydroxide product, or may be a raw material produced by a known method such as a liquid phase synthesis method using nitrate or chloride. The particle size of the raw material powder is not limited as long as a desired layered double hydroxide dense body is obtained, but the volume-based D50 average particle size is preferably 0.1 to 1.0 μm, more preferably 0.3. ~ 0.8 μm. This is because if the particle size of the raw material powder is too fine, the powder tends to aggregate, and there is a high possibility that pores will remain during molding, and if it is too large, the moldability will deteriorate.

If desired, the raw material powder may be calcined to obtain an oxide powder. The calcining temperature at this time is somewhat different depending on the constituent M ²⁺ and M ³⁺ , but is preferably 500 ° C. or lower, more preferably 380 to 460 ° C., in a region where the raw material particle size does not change significantly.

(2) Production of molded body A raw material powder is molded to obtain a molded body. In this molding, a molded body after molding and before firing (hereinafter referred to as a molded body) is 43 to 65%, more preferably 45 to 60%, and even more preferably 47% to 58%. For example, it is preferably performed by pressure molding. The relative density of the molded body is calculated by calculating the density from the size and weight of the molded body and dividing by the theoretical density, but the weight of the molded body is affected by the adsorbed moisture. It is preferable to measure the relative density after the molded body using the raw material powder stored for 24 hours or more in a desiccator having a room temperature and a relative humidity of 20% or less, or after storing the molded body under the above conditions. However, when the raw material powder is calcined to form an oxide powder, the relative density of the compact is preferably 26 to 40%, more preferably 29 to 36%. The relative density in the case of using oxide powder is based on the assumption that each metal element constituting the layered double hydroxide has changed to oxide by calcining, and the converted density obtained as a mixture of each oxide is the denominator. As sought. The pressure forming described as an example may be performed by a uniaxial press of a mold, or may be performed by cold isostatic pressing (CIP). In the case of using cold isostatic pressing (CIP), it is preferable to put the raw material powder in a rubber container and vacuum-seal it or use a preformed one. In addition, you may shape | mold by well-known methods, such as slip casting and extrusion molding, and it does not specifically limit about a shaping | molding method. However, when the raw material powder is calcined to obtain an oxide powder, it is limited to the dry molding method. The relative density of these compacts not only affects the strength of the resulting compact, but also affects the degree of orientation of the layered double hydroxides that usually have a plate shape. The relative density is preferably set within the above range.

(3) Firing step The molded body obtained in the above step is fired to obtain an oxide fired body. This firing is preferably performed so that the oxide fired body has a weight of 57 to 65% of the weight of the compact and / or a volume of 70 to 76% or less of the volume of the compact. When it is 57% or more of the weight of the molded product, it is difficult to generate a heterogeneous phase that cannot be regenerated during regeneration into a layered double hydroxide in the subsequent step. Densify. Further, when it is 70% or more of the volume of the molded body, it is difficult to generate a heterogeneous phase when regenerating into a layered double hydroxide in a subsequent process, and cracks are hardly generated. Done and fully densified in later steps. When the raw material powder is calcined to obtain an oxide powder, it is preferable to obtain an oxide fired body of 85 to 95% of the weight of the compact and / or 90% or more of the volume of the compact. Regardless of whether or not the raw material powder is calcined, the firing is preferably performed so that the oxide fired body has a relative density of 20 to 40% in terms of oxide, more preferably 20 to 35. %, More preferably 20-30%. Here, the relative density in terms of oxide means that each metal element constituting the layered double hydroxide is changed to an oxide by firing, and the converted density obtained as a mixture of each oxide is used as the denominator. It is the obtained relative density. A preferable baking temperature for obtaining the oxide fired body is 400 to 850 ° C, more preferably 700 to 800 ° C. It is preferable to hold | maintain for 1 hour or more with the calcination temperature in this range, and a more preferable holding time is 3 to 10 hours. Further, in order to prevent moisture and carbon dioxide from being released due to rapid temperature rise and cracking the molded body, the temperature rise for reaching the firing temperature is preferably performed at a rate of 100 ° C./h or less. Preferably it is 5-75 degreeC / h, More preferably, it is 10-50 degreeC / h. Therefore, it is preferable to secure a total firing time from temperature increase to temperature decrease (100 ° C. or lower) of 20 hours or more, more preferably 30 to 70 hours, and further preferably 35 to 65 hours.

(4) Regeneration step to layered double hydroxide The oxide fired body obtained in the above step is held in or directly above the aqueous solution containing the n-valent anion (A ⁿ⁻ ) and layered double hydroxide. It regenerates into a product, thereby obtaining a layered double hydroxide solidified body rich in moisture. That is, the layered double hydroxide solidified body obtained by this production method inevitably contains excess moisture. The anion contained in the aqueous solution may be the same kind of anion as that contained in the raw material powder, or may be a different kind of anion. The holding of the oxide fired body in an aqueous solution or immediately above the aqueous solution is preferably performed by a hydrothermal synthesis method in a sealed container, and an example of such a sealed container is a sealed container made of Teflon, more preferably. Is a sealed container having a stainless steel jacket on the outside. The layered double hydroxide is preferably formed by maintaining the oxide fired body at 20 ° C. or more and less than 200 ° C. so that at least one surface of the oxide fired body is in contact with the aqueous solution, and a more preferable temperature is 50 to 180. And a more preferable temperature is 100 to 150 ° C. It is preferable that the oxide sintered body is maintained at such a layered double hydroxide formation temperature for 1 hour or more, more preferably 2 to 50 hours, and further preferably 5 to 20 hours. With such a holding time, it is possible to avoid or reduce the occurrence of a heterogeneous phase by sufficiently regenerating the layered double hydroxide. The holding time is not particularly problematic if it is too long, but it may be set in a timely manner with emphasis on efficiency.

  When carbon dioxide (carbonate ion) in the air is assumed as an anion species of an aqueous solution containing an n-valent anion used for regeneration into a layered double hydroxide, ion-exchanged water can be used. In the hydrothermal treatment in the sealed container, the fired oxide body may be submerged in the aqueous solution, or the treatment may be performed in a state where at least one surface is in contact with the aqueous solution using a jig. When the treatment is performed in a state where at least one surface is in contact with the aqueous solution, the amount of excess water is small compared to complete submergence, so that the subsequent steps may be completed in a short time. However, if the amount of the aqueous solution is too small, cracks are likely to occur. Therefore, it is preferable to use moisture equal to or greater than the weight of the fired body.

(5) Dehydration process Excess water is removed from the water-rich layered double hydroxide solidified product obtained in the above process. Thus, the layered double hydroxide dense body of the present invention is obtained. The step of removing excess water is preferably performed in an environment of 300 ° C. or lower and an estimated relative humidity of 25% or higher at the maximum temperature of the removal step. In order to prevent rapid evaporation of moisture from the layered double hydroxide solidified body, when dehydrating at a temperature higher than room temperature, it should be re-enclosed in the sealed container used in the regeneration process to the layered double hydroxide. preferable. The preferable temperature in that case is 50-250 degreeC, More preferably, it is 100-200 degreeC. Moreover, the more preferable relative humidity at the time of spin-drying | dehydration is 25 to 70%, More preferably, it is 40 to 60%. Dehydration may be performed at room temperature, and there is no problem as long as the relative humidity is within a range of 40 to 70% in a normal indoor environment.

  The present invention is more specifically described by the following examples.

Example 1
As a hydroxide ion conductive solid electrolyte for use in the metal-air secondary battery of the present invention, a disk-like hydrotalcite compact (hereinafter referred to as a 13% diameter and 0.5 mm thickness) having a relative density of 93%. The hydrotalcite test piece was prepared as follows. Hydrotalcite is a kind of typical layered double hydroxide. A hydrotalcite powder (DHT-6, manufactured by Kyowa Chemical Industry Co., Ltd.), which is a commercially available layered double hydroxide, was prepared as a raw material powder. The composition of this raw material powder was Mg ²⁺ _0.75 Al ³⁺ _0.25 (OH) ₂ CO ₃ ^n- _{0.25 / n} · mH ₂ O. The raw material powder was filled in a 16 mm diameter mold and uniaxial press molding was performed at a molding pressure of 200 kgf / cm ² to obtain a molded body having a relative density of 48% and a thickness of about 2 mm. The relative density was measured on a molded article stored at room temperature and a relative humidity of 20% or less for 24 hours. The obtained molded body was fired in an alumina sheath. In this firing, in order to prevent moisture and carbon dioxide from being released due to rapid temperature rise and cracking of the molded body, the temperature was raised at a rate of 100 ° C./h or less, and held at 700 ° C. for 5 hours. Thereafter, cooling was performed. The total firing time from the temperature increase to the temperature decrease (100 ° C. or less) was 60 hours. The fired body thus obtained had a weight and volume of 62% of the weight of the molded body and 74% of the volume of the molded body, and had a relative density of 22% in terms of oxide. The fired body was sealed in a Teflon sealed container with a stainless steel jacket on the outside together with ion-exchanged water in the atmosphere, and subjected to hydrothermal treatment under regeneration conditions including holding at 100 ° C. for 5 hours. Obtained. Since the sample cooled to room temperature contained excess moisture, the moisture on the surface was gently wiped off with a filter paper or the like. The sample thus obtained was naturally dehydrated (dried) in a room at 20 to 30 ° C. and a relative humidity of about 40 to 60% to obtain a test piece. When the obtained test piece was visually observed, no cracks were observed.

The density was calculated from the size and weight of the test piece, and the relative density of the test piece was determined by dividing this density by the theoretical density, which was 93%. In calculating the theoretical density, the JCPDS card No. 1 was used as the hydrotalcite theoretical density of Mg / Al = 3. 2.06 g / cm ³ described in 22-22700 is used as the theoretical density of hydrotalcite with Mg / Al = 2. 2.09 g / cm ³ described in 70-2151 was used.

  In addition, the crystal phase of the test piece was measured with an X-ray diffractometer (D8 ADVANCE, manufactured by Bulker AXS) under the measurement conditions of voltage: 40 kV, current value: 40 mA, measurement range: 5-70 °, and JCPDS card NO. . It identified using the diffraction peak of the hydrotalcite described in 35-0965, and evaluated according to the following references | standards. As a result, only peaks due to hydrotalcite were observed.

Example 2
In order to confirm the conductivity in the configuration of the zinc-air battery of the hydrotalcite test piece obtained in Example 1, a zinc-air battery was simply constructed and the conductivity was measured. FIG. 4 shows a schematic diagram of the measurement system. The measurement system shown in FIG. 4 is a measurement system including a zinc-air battery 100 using a hydrotalcite test piece as a solid electrolyte body. In this zinc-air battery 100, a zinc foil (manufactured by Niraco Co., Ltd., thickness 0.05 mm × width 5 mm × length 50 mm) is used as the negative electrode 102, and 1 mol / l KOH aqueous solution is used as the electrolyte 104, and the air electrode (positive electrode) 106 is a platinum-supported carbon catalyst (E-TEK, 7 mm square), and the positive electrode current collector 108 is a platinum mesh (Nilaco Corporation, 7 mm square). The air electrode (positive electrode) 106 is separated from the electrolytic solution 104 through the hydrotalcite test piece 110 and the nonwoven fabric 112 so as to conduct hydroxide ions, while the hydrotalcite test piece 110 is separated from the electrolytic solution 104 through the nonwoven fabric 112. It can be contacted. The platinum-supported carbon catalyst as the air electrode 106 has a carbon mesh on one side, and a mixed powder of carbon and platinum adhered on the mesh on the other side (platinum supported amount: 5 g / m ² ). The carbon mesh side was used facing the positive electrode current collector 108. A measurement system was constructed by connecting the zinc-air battery 100 to the electrochemical measurement device 114 via the negative electrode 102 and the positive electrode current collector 108. This electrochemical measuring device 114 is a combination of a potentio / galvanostat (Solarartron, Model 1287) and a frequency response analyzer (FRA) (Solartron, Model 1260). The zinc-air battery 100 thus connected to the electrochemical measuring device 114 is installed in the constant temperature and humidity chamber 116 (manufactured by Yamato Scientific Co., Ltd., constant temperature and humidity chamber IW222), and AC impedance measurement and constant current measurement are performed. went.

ここで、σは伝導度（Ｓ／ｃｍ）、Ｒは抵抗（Ω）、Ｌは試料の厚さ（ｃｍ）、Ｓは電極面積（ｃｍ^２）である。この交流インピーダンス測定は、測定温度３０〜８０℃、相対湿度４０〜９０％（共に恒温恒湿器の設定値）、周波数：１ＭＨｚ〜０．１Ｈｚ、交流電圧振幅：１０ｍＶの条件で行った。なお、この測定は、温度及び湿度を設定して２０分後、すなわち起電力の値が安定した後に開始した。 (AC impedance measurement)
Using the measurement system obtained above, a total of 12 points of data were acquired at three points of 40, 70 and 90% relative humidity at four points of 30, 40, 60 and 80 ° C. Using the resistance component obtained by the AC impedance method with pseudo four terminals, the ionic conductivity was calculated by the following equation. At this time, the temperature and humidity were controlled to be kept constant (temperature fluctuation range was ± 0.1 ° C. and humidity fluctuation range was ± 2%).

Here, σ is conductivity (S / cm), R is resistance (Ω), L is the thickness of the sample (cm), and S is the electrode area (cm ² ). This AC impedance measurement was performed under the conditions of a measurement temperature of 30 to 80 ° C., a relative humidity of 40 to 90% (both are set values of a constant temperature and humidity chamber), a frequency of 1 MHz to 0.1 Hz, and an AC voltage amplitude of 10 mV. This measurement was started 20 minutes after setting the temperature and humidity, that is, after the value of the electromotive force was stabilized.

(Constant current measurement)
In addition, in order to obtain a discharge curve and evaluate the charge / discharge characteristics, the value of the voltage when a constant current was passed by direct current was recorded. This constant current measurement was performed under the conditions of a measurement temperature of 80 ° C., a relative humidity of 90% (set value of a constant temperature and humidity chamber), a current of 1 × 10 ⁻⁶ A, and a measurement time of 5 minutes.

(result)
Table 1 shows the ionic conductivity obtained by the AC impedance method. FIG. 5 shows the temperature dependence of ionic conductivity, and FIG. 6 shows the relative humidity dependence of ionic conductivity. Furthermore, FIG. 7 shows the charge / discharge characteristics obtained by constant current measurement.

  As shown in FIG. 5, the hydrotalcite specimen has a large temperature dependence of the ionic conductivity, and hence a large activation energy, so that the temperature range for keeping the conductivity within a certain range is narrow and a slight temperature. The conductivity is easily affected by the change (calculating the activation energy at each relative humidity based on the slope of each line shown in FIG. 5 is 0.61 eV at 90% relative humidity, 0.47 eV at 70%, 40 % Is 0.30 eV). That is, in the case of an ionic conductor with a small activation energy, the change in ionic conductivity with respect to the temperature change is insensitive, so the temperature range for obtaining a certain conductivity is wide, but like hydrotalcite This is not the case with hydroxide ion conductive solid electrolyte bodies. Further, as shown in FIG. 6, the ionic conductivity of the hydrotalcite test piece varies greatly with respect to humidity. Therefore, in order to obtain a stable output, it can be said that it is effective to control the temperature and / or humidity, preferably both of them substantially constant, preferably constant.

10 Zinc-air secondary battery 12 Air electrode (positive electrode)
14 hydroxide ion conductive solid electrolyte body 16 metal negative electrode 18 positive electrode current collector 20 battery container 20a air hole 22 positive electrode container 24 negative electrode container 26 positive electrode gasket 28 negative electrode gasket 30, 50 lithium air secondary battery 32, 52 air electrode ( Positive electrode)
34,54 Hydroxide ion conductive solid electrolyte body 36,56 Separator 38,58 Negative electrode 40,60 Alkaline electrolyte 62 Positive electrode container 62a Air hole 64 Negative electrode container 66 Positive electrode gasket 68 Negative electrode gasket 70 Conductive buffer material

Claims (10)

A method of using a metal-air secondary battery, wherein the metal-air secondary battery is a layered double hydroxide dense body having a relative density of 88% or more, and the solid ion electrolyte An air electrode as a positive electrode provided in close contact with one surface side of the electrolyte body, and a metal negative electrode provided on the other surface side of the solid electrolyte body,
The metal air battery temperature and / or humidity in the air supplied to the air electrode saw including to control substantially constant, using the alkaline electrolyte between the said solid electrolyte body negative electrode, How to use a metal-air secondary battery.   The method according to claim 1, wherein both the temperature of the metal-air secondary battery and the humidity in the air that can come into contact with the air electrode are controlled to be substantially constant.   3. The method according to claim 1, further comprising sending air having a humidity adjusted to be substantially constant from the outside into a container housing the battery.   The method according to any one of claims 1 to 3, wherein the temperature of the metal-air secondary battery is controlled to fall within a temperature fluctuation range of less than ± 5 ° C.   The method according to any one of claims 1 to 4, wherein the humidity in the air supplied to the air electrode is controlled to fall within a relative humidity fluctuation range of less than ± 5%. The hydroxide ion conductive solid electrolyte body is
General ^{_{formula: M 2+ 1-x M 3+}} x (OH) 2 A n- x / n · mH 2 O
(Wherein, M ²⁺ is at least one or more divalent cations, M ³⁺ is at least one or more trivalent cations, A ^n-n-valent anion, n represents an integer of 1 or more, x Is 0.1 to 0.4)
The method as described in any one of Claims 1-5 which consists of the layered double hydroxide shown by these. Among the general formula, at least ^{M 2+} is ^{Mg 2+, M 3+} comprises ^{Al 3+, A n-is} OH ^- containing and / or _CO ^{3 2-} The method of claim 6. The method according to any one of claims 1 to 7 , wherein the metal negative electrode comprises zinc or a zinc alloy. The method according to any one of claims 1 to 7 , wherein the metal negative electrode comprises lithium or a lithium alloy. The method according to any one of claims 1 to 7 and 9 , wherein a lithium ion-containing aqueous solution is used as an electrolyte between the solid electrolyte body and the negative electrode.

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