JP2017174771A - Metal air battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal air battery capable of stably supplying electric energy for a long period of time.SOLUTION: The metal air battery includes: a positive electrode that is an air electrode; and a negative electrode that uses a metal species for a negative electrode active material. The metal air battery has a portion for storing a negative electrode active material, and at least a part of a bottom surface of the storage portion is formed with a current collector.SELECTED DRAWING: None

Description

The present invention relates to a metal-air battery. More specifically, the present invention relates to a metal-air battery using an air electrode as a positive electrode and a metal electrode as a negative electrode.

The metal-air battery uses a metal material as an active material for a negative electrode and oxygen in the air as an active material for a positive electrode. Therefore, there is no need for a space for filling the positive electrode active material, and the portion can be filled with the negative electrode active material, so that it is known as a battery that can realize a high energy density. One such metal-air battery is a zinc-air battery that uses zinc as the negative electrode active material.
Zinc has long been used as a battery material, and is currently used in many primary batteries. In recent years, application studies as a secondary battery have been activated. Conventionally, it has been said that a zinc-air battery is not suitable for a secondary battery because zinc easily induces a short circuit due to dendrite formed during charging. For this reason, the method of supplying zinc physically called a mechanical charge system is known (refer to patent documents 1-4). Using this method, it is possible to replenish energy by physically supplying zinc, so the time required for supply is short, and in an electric vehicle, the advantage of being able to replenish electric energy in the same amount of time as supplying gasoline There is. Further, in a large-scale power generation system or the like, there is an advantage that an energy medium that can be completely recycled can be configured by accumulating electrical energy in the form of zinc and supplying it to each home, factory, car, and the like.

JP 2004-362869 A JP 2004-362868 A JP 2005-509262 A Japanese Patent Laying-Open No. 2015-79583

Among these conventional mechanical charge type batteries, a battery of a type in which a negative electrode metal material having a predetermined shape as in Patent Documents 1 and 2 is replaced requires a member for use in a structure for removal or the like. Therefore, it is difficult to increase the metal material, and in order to increase the battery capacity, it is necessary to enlarge the entire battery. Patent Document 3 describes an electrochemical cell of a type in which one or more metal fuel anodes composed of a negative electrode active material and a current collector are inserted into one or more containers. Since the negative electrode active material may fall off from the current collector when the amount of the material is increased, the amount of the negative electrode active material cannot be increased too much. Furthermore, Patent Document 4 describes a battery of a system in which only zinc powder is introduced, but a current collector parallel to the direction of gravity is arranged at a position away from the bottom surface with respect to zinc powder that settles by gravity. Therefore, the energy of the supplied zinc cannot be sufficiently extracted. Thus, none of the batteries was satisfactory in terms of performance.

This invention is made | formed in view of the said present condition, and aims at providing the metal air battery which can supply an electric energy stably for a long period of time.

The inventor has made various studies on metal-air batteries capable of stably supplying electric energy for a long period of time. As a result, the metal-air battery is provided with a portion for storing a negative electrode active material, and at least the bottom surface of the storage portion. I thought of forming a part of the current collector. In this way, there is no problem that the negative electrode active material falls off the current collector and cannot be effectively used for the battery reaction. The inventors found that the metal-air battery can be used effectively and can stably supply electric energy for a long period of time, and arrived at the present invention by conceiving that the above problems could be solved brilliantly. Is.

That is, the present invention is a metal-air battery having a positive electrode that is an air electrode and a negative electrode that uses a metal species as a negative electrode active material, the metal-air battery including a part that stores a negative electrode active material, and the storage part The metal-air battery is characterized in that at least a part of the bottom surface is formed of a current collector.
The present invention is described in detail below.
A combination of two or more preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.

<Metal-air battery>
The metal-air battery of the present invention is characterized in that it has a negative electrode active material storage part having at least a part of the bottom surface formed of a current collector. In the case of a battery in which a negative electrode in which a negative electrode active material is attached to a current collector as in Patent Document 3, the negative electrode active material is dropped from the current collector and cannot be used effectively for a battery reaction. There is a possibility that a problem occurs. However, if the negative electrode active material is placed in the storage site as described above, such a problem does not occur. In addition, as compared with a battery in which a metal material serving as a negative electrode active material is replaced, a larger number of negative electrode active materials can be mounted on the battery because a structural member for removal is unnecessary.
The storage site of the negative electrode active material in the battery of the present invention is only required to have at least a part of the bottom surface formed of a current collector, but the entire bottom surface is preferably formed of a current collector. More preferably, the entire side surface and the entire bottom surface of the storage site are formed of a current collector.

Further, the size and shape of the storage site of the negative electrode active material are not particularly limited, but it is preferable that the storage site is a space having a depth reaching from the upper end to the bottom surface of the battery in terms of storing more negative electrode active material.
Further, only the negative electrode active material may be contained in the storage site, and a current collector may be contained in addition to the negative electrode active material. It is preferable that a current collector is placed in the storage site because the negative electrode active material is far away from the current collector and the negative electrode active material can be effectively utilized by the charge / discharge reaction.
The shape of the current collector placed in the storage site is not particularly limited, and may be a plate shape or a porous metal material such as a metal foam. It is one of the preferred embodiments of the present invention that a material is placed and a negative electrode active material is placed in the pores of the porous metal material. When the negative electrode active material is put in the hole of the metal foam, the distance between the negative electrode active material and the current collector is reduced, and the negative electrode active material can be effectively utilized by the charge / discharge reaction.

It is preferable that the storage part which the metal air battery of this invention has has a supply port which can supply a negative electrode active material from the outside. As a result, the negative electrode active material can be continuously supplied to the storage site, and stable electric energy can be supplied over a longer period of time.
The position of the supply port is not particularly limited, but it is preferable that the supply port is at the upper part of the storage site in order to facilitate supply.

The metal-air battery of the present invention only needs to have an electrode that is an air electrode and a negative electrode that uses a metal species as a negative electrode active material, but the air electrode is a positive electrode for discharge, and for charging separately from the air electrode. It is preferable that the battery is a third electrode type battery having a positive electrode. In the metal-air battery of the present invention, discharge is possible if the negative electrode active material is present in the storage part, and if the negative electrode active material is continuously supplied to the storage part as described above, it is not electrically charged. However, if the metal-air battery is a third-pole battery, it can store energy electrically by charging in addition to supplying physical energy from the outside. Is also preferable.

In the metal-air battery of the present invention, a separator is preferably disposed between the positive electrode and the negative electrode. By arranging the separator, a short circuit between the positive electrode and the negative electrode can be effectively suppressed. In addition, by arranging the separator, it is possible to suppress a short circuit between the negative electrode and the positive electrode for charging due to the growth of dendrite when zinc, nickel, or the like is used as the negative electrode active material.
When the metal-air battery of the present invention is a third electrode type battery, it is preferable that a separator is disposed either between the positive electrode for charging and the electrolytic solution or between the electrolytic solution and the negative electrode. .

When the metal-air battery of the present invention is a battery of the third electrode system, the separator installed either between the positive electrode for charging and the electrolytic solution or between the electrolytic solution and the negative electrode is anion conductive. It is preferable that it is formed of a material. Since this separator is an anion conductive membrane formed of an anion conductive material, the short circuit between the electrodes due to dendrite growth is more effective while ensuring good permeability of the anion necessary for the electrode reaction. Can be suppressed.
The anion conductive membrane means a membrane that preferentially transmits anions. This is a concept common to any invention described in the following publicly known documents belonging to the same or similar technical field as the present invention. In the present invention, the anion conductive membrane means a membrane (layer) that transmits anions, particularly hydroxide ions. The anion conductive material forming the anion conductive membrane will be described later.
(Refer to Japanese translations of PCT publication No. 2014-503689, JP 2013-145758, JP 2013-091598, JP 2014-011000, JP 2013-211201.)

The configuration of the metal-air battery of the present invention is not particularly limited as long as it has a positive electrode that is an air electrode, a negative electrode having a metal species as a negative electrode active material, and a storage site for the negative electrode active material, It is a configuration in which a positive electrode for charging is arranged in the electrolyte solution between the storage site of the negative electrode active material and the air electrode, and a separator is arranged between the storage site of the negative electrode active material and the positive electrode for charging. This is one of the preferred forms of the metal-air battery of the present invention. With such a configuration, the negative electrode active material at the storage site can be fully utilized for the discharge reaction, and charging can be sufficiently performed while effectively suppressing the short circuit between the positive electrode and the negative electrode and the growth of dendrite. it can.
More preferably, there is a negative electrode active material storage part in the center of the battery, there are air electrodes on the left and right sides thereof, and a positive electrode for charging is disposed in the electrolyte between the storage part and the left and right air electrodes, respectively. It is the structure as shown in FIG. 1 in which separators are respectively disposed between the active material storage site and the positive electrode for charging. When the metal-air battery of the present invention has the configuration as shown in FIG. 1, more current can be taken out during discharging.

<Negative electrode>
The active material of the negative electrode in the metal-air battery of the present invention includes cadmium species, lithium species, sodium species, magnesium species, lead species, zinc species, tin species, silicon-containing materials, hydrogen storage alloy materials, noble metal materials such as platinum, etc. What is normally used as a negative electrode active material of a battery can be used as a negative electrode active material. As described above, since the growth of dendrites can be effectively suppressed by installing an anion conductive membrane as a separator between the negative electrode and the positive electrode, among the above, zinc species or cadmium can be used as the negative electrode. Species are preferred.
Here, the zinc species means a zinc simple metal or a zinc compound, and the cadmium species means a cadmium simple metal or a cadmium compound. The same applies to lithium species, sodium species, magnesium species, lead species, zinc species, and tin species. Examples of the compound include oxides, sulfides and hydroxides.

The negative electrode active material preferably has an average particle size of 1 nm to 500 μm. More preferably, they are 5 nm-200 micrometers, More preferably, they are 10 nm-100 micrometers, Especially preferably, they are 10 nm-60 micrometers.
The average particle diameter can be measured using a particle size distribution measuring device.

The negative electrode is preferably one in which a negative electrode active material layer is formed so as to be in contact with the current collector. The mass ratio of the active material contained in the active material layer is preferably 40% by mass or more in 100% by mass of the entire active material layer. When the amount of the active material is in such a range, the capacity of the electrode can be made sufficient. More preferably, it is 60 mass% or more, More preferably, it is 80 mass% or more, Especially preferably, it is 85 mass% or more. The mass ratio is preferably 99.9% by mass or less, more preferably 99.5% by mass or less, still more preferably 99% by mass or less, and 98% by mass or less. Is particularly preferred.

The negative electrode active material layer may contain a binder, a conductive auxiliary agent and the like in addition to the active material.
Various binders can be used, which may be either thermoplastic or thermosetting. Polymers containing halogen atoms such as polyvinylidene fluoride and polytetrafluoroethylene, and hydrocarbon moieties such as polyolefin. -Containing polymers, aromatic group-containing polymers such as polystyrene; ether group-containing polymers such as alkylene glycol; hydroxyl group-containing polymers such as polyvinyl alcohol; amide bond-containing polymers such as polyamide and polyacrylamide; imide group-containing polymers such as polymaleimide; Carboxyl group-containing polymers such as (meth) acrylic acid; Carboxylic acid group-containing polymers such as poly (meth) acrylates; Sulfonate moiety-containing polymers; Quaternary ammonium salt and quaternary phosphonium salt-containing polymers; Ion exchange Polymer; natural rubber; Artificial rubber such as Ren butadiene rubber (SBR); hydroxyalkylcelluloses (e.g., hydroxyethylcellulose), sugars such as carboxymethyl cellulose; amino group-containing polymers such as polyethyleneimine; and polyurethane.

It is preferable that the mass ratio in the whole active material layer of the said binder is 0.3-30 mass%. More preferably, it is 0.5-15 mass%, More preferably, it is 1-10 mass%, Most preferably, it is 2-6 mass%.

Although it does not restrict | limit especially as said conductive support agent, For example, 1 type, or 2 or more types, such as conductive carbon, conductive ceramics, metals, such as zinc, copper, brass, nickel, silver, bismuth, indium, lead, and tin Can be used.

In the case where the negative electrode active material layer contains a conductive auxiliary agent, the proportion of the conductive auxiliary agent is preferably 0.0001 to 100% by mass with respect to 100% by mass of the active material in the negative electrode active material layer. When the content ratio of the conductive assistant is within such a range, better battery performance can be exhibited. More preferably, it is 0.0005-60 mass%, More preferably, it is 0.001-40 mass%.

The negative electrode active material layer includes, as other components, a compound having at least one element selected from the group consisting of elements belonging to Group 1 to Group 17 of the periodic table, an organic compound, and an organic compound salt. It may contain at least one selected from the group.
When the negative electrode active material layer contains other components, the content ratio of the other components in the negative electrode active material layer is preferably 10% by mass or less, more preferably 5% by mass or less, More preferably, it is 1 mass% or less.

The thickness of the negative electrode active material layer is preferably 100 μm or more, more preferably 200 μm or more, further preferably 500 μm or more, and particularly preferably 1 mm or more. The thickness of the active material layer is preferably 10 mm or less, for example, and more preferably 5 mm or less.
The thickness of the active material layer can be measured with a micrometer.

In the present invention, the material of the negative electrode current collector is not particularly limited, (electrolytic) copper foil, copper mesh (expanded metal), copper alloy such as foamed copper, punched copper, brass, brass foil, brass mesh (expanded metal) , Foamed brass, punched brass, nickel foil, corrosion resistant nickel, nickel mesh (expanded metal), punched nickel, metal zinc, corrosion resistant metal zinc, zinc foil, zinc mesh (expanded metal), (punched) steel sheet, imparted conductivity Non-woven fabric; (electrolytic) copper foil / copper mesh (expanded metal) / copper alloy such as Ni / Zn / Sn / Pb / Hg / Bi / In / Tl / brass etc.・ Brass mesh (expanded metal) ・ Foamed brass ・ Punching brass ・ Nickel foil ・ Corrosion resistant nickel ・ Nickel (Expanded metal), punched nickel, metal zinc, corrosion-resistant metal zinc, zinc foil, zinc mesh (expanded metal), (punched) steel plate, non-woven fabric; Ni, Zn, Sn, Pb, Hg, Bi, In, Tl, brass (Electrolytic) copper foil, copper mesh (expanded metal), foamed copper, punched copper, copper alloys such as brass, brass foil, brass mesh (expanded metal), foamed brass, punched brass, nickel foil, corrosion resistance Nickel, nickel mesh (expanded metal), punched nickel, metal zinc, corrosion-resistant metal zinc, zinc foil, zinc mesh (expanded metal), (punched) steel sheet, non-woven fabric, silver, alkaline (storage) battery, and air zinc battery Examples include materials used as bodies and containers.
Among these, examples of the porous metal material described above include foam metal materials, and foam copper, foam brass, and the like can be used.

<Positive electrode for charging>
When the metal-air battery of the present invention is a third electrode system, the positive electrode for charging constituting the battery is not particularly limited as long as it can function as the positive electrode for charging, but on the surface facing the negative electrode On the other hand, a structure or material that can conduct ions in the vertical direction is preferable, and a porous metal plate or the like is preferable. As the porous metal plate, a punched metal plate or a foamed metal plate included in a material that can be used as a current collector constituting the negative electrode can be used.

The thickness of the positive electrode for charging is not particularly limited, but is preferably 0.01 to 2 mm. More preferably, it is 0.1-1 mm.
The thickness of the charging positive electrode can be measured with a micrometer.

<Air electrode (positive electrode for discharge)>
The air electrode constituting the metal-air battery of the present invention (in the case of the third electrode system, the discharge air electrode) is not particularly limited as long as it functions as an air electrode, but includes an air electrode catalyst. It is more preferable that the air electrode catalyst layer is formed on the current collector.
Examples of the air electrode catalyst include conductive carbon such as ketjen black, acetylene black, denka black, carbon nanotube, fullerene, metal, metal oxide, metal hydroxide, metal sulfide, and the like. Or 2 or more types can be used.

The mass ratio of the air electrode catalyst contained in the air electrode catalyst layer is preferably 5% by mass or more in 100% by mass of the entire air electrode catalyst layer. When the ratio of the air electrode catalyst is within such a range, the function of the air electrode can be made sufficient. More preferably, it is 10 mass% or more, More preferably, it is 20 mass% or more. Moreover, it is preferable that this mass ratio is 98 mass% or less, and it is more preferable that it is 95 mass% or less.

The air electrode catalyst layer may contain a binder in addition to the air electrode catalyst.
As a binder, the thing similar to the binder which the negative electrode active material layer mentioned above contains can be used.
The mass ratio of the binder in the air electrode catalyst layer is preferably 0.1 to 10% by mass. More preferably, it is 0.5-8 mass%, More preferably, it is 1-5 mass%.

The air electrode catalyst layer may contain a water repellent and the like as other components in addition to the air electrode catalyst and the binder.
In addition to these, the mass ratio of the components in the air electrode catalyst layer is preferably 5% by mass or less. More preferably, it is 3 mass% or less, More preferably, it is 2 mass% or less.

The thickness of the air electrode catalyst layer is preferably 5 μm or more, more preferably 10 μm or more, and further preferably 20 μm or more. The thickness of the active material layer is preferably, for example, 1 mm or less, and more preferably 500 μm or less.
The thickness of the active material layer can be measured with a micrometer.

As the current collector constituting the air electrode catalyst, the same current collector as that constituting the metal electrode serving as the negative electrode described above can be used.

<Electrolyte>
As the electrolytic solution constituting the metal-air battery of the present invention, those usually used as an electrolytic solution for a storage battery can be used, and are not particularly limited. For example, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, γ-butyrolactone , Dimethoxymethane, diethoxymethane, dimethoxyethane, tetrahydrofuran, methyltetrahydrofuran, diethoxyethane, dimethyl sulfoxide, sulfolane, acetonitrile, benzonitrile, ionic liquid, fluorine-containing carbonates, fluorine-containing ethers, polyethylene glycols, fluorine-containing Examples include polyethylene glycols. These organic solvent electrolytes can be used alone or in combination of two or more. Examples of the aqueous electrolyte include potassium hydroxide aqueous solution, sodium hydroxide aqueous solution, lithium hydroxide aqueous solution, zinc sulfate aqueous solution, zinc nitrate aqueous solution, zinc phosphate aqueous solution and zinc acetate aqueous solution. Among these, alkaline electrolytes such as an aqueous potassium hydroxide solution, an aqueous sodium hydroxide solution, and an aqueous lithium hydroxide solution are preferable. The aqueous electrolyte solution can be used alone or in combination of two or more. The aqueous electrolyte solution may contain the organic solvent electrolyte solution.

<Separator>
When the metal-air battery of the present invention has an anion conductive membrane as a separator, the thickness of the separator is not particularly limited, but is preferably 1 μm to 1000 μm. More preferably, it is 5 micrometers-500 micrometers, More preferably, they are 10 micrometers-100 micrometers.
The thickness of the separator can be measured with a micrometer.

The metal-air battery of the present invention is of the third electrode type, and is between the negative electrode and the electrolytic solution, or between the positive electrode (the positive electrode for charging in the case of the third electrode type battery) and the electrolytic solution. When it has a separator, this separator may be an anion conductive membrane or a separator other than an anion conductive membrane, but is preferably an anion conductive membrane.

As separators other than the anion conductive membrane, nonwoven fabric, filter paper, polyolefin such as polyethylene and polypropylene, polytetrafluoroethylene moiety-containing polymer, polyvinylidene fluoride moiety-containing polymer, cellulose, fibrillated cellulose, viscose rayon, cellulose acetate, Hydroxyalkyl cellulose, carboxymethyl cellulose, polyvinyl alcohol-containing polymer, cellophane, polystyrene-containing aromatic ring site-containing polymer, polyacrylonitrile site-containing polymer, polyacrylamide site-containing polymer, halogen-containing polymer such as polyvinyl fluoride site-containing polymer, polyamide site-containing Polymer, Polyimide moiety-containing polymer, Nylon and other ester moiety-containing polymer, Poly (meth) acrylic acid moiety-containing poly -Poly (meth) acrylate site-containing polymer, hydroxyl group-containing polymer such as polyisoprenol and poly (meth) allyl alcohol, carbonate group-containing polymer such as polycarbonate, ester group-containing polymer such as polyester, carbamate such as polyurethane, Carbamide group site-containing polymer, agar, gel compound, organic-inorganic hybrid (composite) compound, ion exchange membrane polymer, cyclized polymer, sulfonate-containing polymer, quaternary ammonium salt-containing polymer, quaternary phosphonium salt polymer, Examples thereof include inorganic substances such as cyclic hydrocarbon group-containing polymers, ether group-containing polymers, and ceramics.

The anion conductive membrane is preferably formed of an anion conductive material including a polymer and a compound containing at least one element selected from Group 1 to Group 17 of the periodic table. The anion conductive membrane formed of such an anion conductive material has a good hydroxide ion permeability, but can sufficiently prevent the diffusion of metal ions having a large ionic radius even in the case of anions. Therefore, even if such a film exists as a separator between the negative electrode and the positive electrode (in the case of the third electrode type, a positive electrode for charging), the metal-air battery of the present invention can exhibit good performance. .
In this case, the anion conductive material may contain a polymer and a compound containing at least one element selected from Group 1 to Group 17 of the periodic table, respectively, or may contain two or more kinds. Moreover, components other than these may be included.
Hereinafter, a polymer contained in the anion conductive material and a compound containing at least one element selected from Group 1 to Group 17 of the periodic table (hereinafter also simply referred to as an inorganic compound) will be described in order.

Examples of the polymer included in the anion conductive material include a hydrocarbon moiety-containing polymer such as polyethylene and polypropylene, an aromatic group-containing polymer typified by polystyrene and styrene-butadiene copolymer; an ether group typified by alkylene glycol and the like. Containing polymer; hydroxyl group-containing polymer represented by polyvinyl alcohol and poly (α-hydroxymethyl acrylate); amide group-containing polymer represented by polyamide, nylon, polyacrylamide, polyvinylpyrrolidone, N-substituted polyacrylamide and the like; Imide group-containing polymers represented by polymaleimide, etc .; Carboxy group-containing polymers represented by poly (meth) acrylic acid, polymaleic acid, polyitaconic acid, polymethylene glutaric acid, etc .; poly (meth) acrylic acid salt, polymer Carboxylate group-containing polymers such as phosphate, polyitaconate, polymethylene glutarate; halogen-containing polymers such as polyvinyl chloride, polyvinylidene fluoride, and polytetrafluoroethylene; epoxy groups such as epoxy resins are opened. Polymer bonded by ring; sulfonate moiety-containing polymer; AR ¹ R ² R ³ B (A represents N or P. B represents an anion such as a halogen anion or OH ^−. R ¹ , R ² and R ³ are the same or different and each represents an alkyl group having 1 to 7 carbon atoms, a hydroxyalkyl group, an alkyl carboxyl group, or an aromatic ring group, and R ¹ , R ² , and R ³ are bonded to form a ring; A quaternary ammonium salt or a quaternary phosphonium salt-containing polymer represented by a polymer to which a group represented by Ion exchange polymers used for ion / anion exchange membranes, etc .; natural rubber; artificial rubber typified by styrene butadiene rubber (SBR), etc .; cellulose, cellulose acetate, hydroxyalkyl cellulose (for example, hydroxyethyl cellulose), carboxy Sugars typified by methylcellulose, chitin, chitosan, alginic acid (salt), etc .; amino group-containing polymers typified by polyethyleneimine; carbamate group site-containing polymers; carbamide group site-containing polymers; epoxy group site-containing polymers; And / or ionized heterocyclic moiety-containing polymer; polymer alloy; heteroatom-containing polymer; low molecular weight surfactant and the like.

Among the above, the polymer contained in the anion conductive material contains at least one selected from the group consisting of an aromatic group, a halogen atom, a carboxyl group, a carboxylate group, a hydroxyl group, an amino group, and an ether group. Or a hydrocarbon.
The halogen atom is preferably a fluorine atom, a chlorine atom or a bromine atom. More preferably, it is a fluorine atom. The carboxylate base is preferably a lithium carboxylate base, a sodium carboxylate base, or a potassium carboxylate base. More preferably, it is a sodium carboxylate base. Examples of the hydrocarbon include polyolefin. Above all, the above-mentioned polymer is comprehensively composed of three points: (1) being an insulator, (2) being capable of thickening and binding anion conductive material powder, and (3) being excellent in physical strength. In view of the above, it is preferable to select appropriately.From such a viewpoint, a hydrocarbon site-containing polymer, an aromatic group-containing polymer, an ether group-containing polymer, a carboxyl group-containing polymer, a carboxylate group-containing polymer, a halogen-containing polymer, Sulfonate moiety-containing polymers, quaternary ammonium salts, quaternary phosphonium salt-containing polymers, and saccharides are preferred. The polymer may be in a fiberized state by heat or pressure. The strength of the active material (layer) or anion conductive material, anion conductivity, and the like can also be adjusted by polymerizing the polymer.

The polymer preferably has a weight average molecular weight of 200 to 7000000. Thereby, the ion conductivity, viscosity, flexibility, strength, and the like of the anion conductive material can be adjusted. The weight average molecular weight is more preferably 400 to 6500000, and still more preferably 500 to 5000000.
The weight average molecular weight can be measured by gel permeation chromatography (GPC).

The mass ratio of the polymer is preferably 0.1% by mass or more with respect to 100% by mass of the anion conductive material. More preferably, it is 1% by mass or more, further preferably 25% by mass or more, more preferably more than 30% by mass, particularly preferably more than 40% by mass, most preferably. Is more than 45% by mass. Moreover, it is preferable that it is 99.9 mass% or less. More preferably, it is 99.5 mass% or less, More preferably, it is 99 mass% or less, More preferably, it is 97 mass% or less, Most preferably, it is 80 mass% or less. Thereby, the crack of an anion conductive material can be made hard to produce.

The mass ratio between the polymer and the inorganic compound in the anion conductive material according to the present invention is preferably 5000000/1 to 1/100000. More preferably, it is 2000000/1-1 / 50,000, More preferably, it is 1000000/1-1/10000. More preferably, it is 1000000/1 to 1/100. Even more preferably, it is 100/3 to 75/100. Most preferably, it is 100 / 50-75 / 100. When the inorganic compound contained in the anion conductive material according to the present invention is hydrotalcite, by satisfying the above mass ratio, the effect of improving the anion conductivity in the anion conductive material and cracking are less likely to occur. Both effects can be remarkably improved.

A compound containing at least one element selected from Group 1 to Group 17 of the periodic table (also referred to simply as an inorganic compound in the present specification) is an alkali metal, an alkaline earth metal, Sc, Y, Lanthanoid, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Ru, Co, Ni, Pd, Cu, Ag, Au, Zn, Cd, B, Al, Ga, In, It is preferably at least one element selected from the group consisting of Tl, C, Si, Ge, Sn, Pb, N, P, Sb, Bi, S, Se, Te, F, Cl, and Br. More preferably, Li, Mg, Ca, Sr, Ba, Sc, Y, lanthanoid, Ti, Zr, Nb, Cr, Mn, Fe, Ru, Co, Ni, Pd, Cu, Zn, Cd, B, Al, It contains at least one element selected from the group consisting of Ga, In, Tl, C, Si, Sn, Pb, N, P, and Bi.

The inorganic compound is preferably at least one compound selected from the group consisting of oxides, hydroxides, layered double hydroxides, sulfuric acid compounds, and phosphoric acid compounds.
Examples of the oxide include alkali metal, Mg, Ca, Sr, Ba, Sc, Y, lanthanoid, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Ru, Co, Ni , Pd, Cu, Ag, Au, Zn, Cd, B, Al, Ga, In, Tl, C, Si, Ge, Sn, N, P, Sb, Bi, S, Se, Te, F, Cl, and , And an oxide containing at least one element selected from the group consisting of Br. More preferably, Li, Na, Mg, Ca, Sr, Ba, Sc, Y, lanthanoid, Ti, Zr, Nb, Cr, Mn, Fe, Ru, Co, Ni, Pd, Cu, Zn, Cd, B, It is an oxide containing at least one element selected from the group consisting of Al, Ga, In, Tl, Si, Sn, Pb, and Bi. More preferred are magnesium oxide, calcium oxide, strontium oxide, barium oxide, bismuth oxide, cobalt oxide, cerium oxide, niobium oxide, tin oxide, and zirconium oxide, and particularly preferred are magnesium oxide, bismuth oxide, cerium oxide, and oxide. Niobium, tin oxide and zirconium oxide. In addition, the cerium oxide may be, for example, a material doped with a metal oxide such as samarium oxide, gadolinium oxide, or bismuth oxide, or a solid solution with a metal oxide such as zirconium oxide. The oxide may have an oxygen defect.

As the hydroxide, for example, magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, cerium hydroxide, and zirconium hydroxide are preferable. In the present specification, the hydroxide refers to a hydroxide other than the layered double hydroxide.

The layered double hydroxide is preferably hydrotalcite, for example. Thereby, the anion conductivity of the anion conductive material can be remarkably improved.
The hydrotalcite is represented by the following formula (1);
[M ¹ _1-x M ² _x (OH) ₂ ] (A ⁿ⁻ ) _{x / n} · mH ₂ O (1)
(In the formula, M ¹ = Mg, Fe, Zn, Ca, Li, Ni, Co, Cu, Mn, etc .; M ² = Al, Fe, Mn, Co, Cr, In, etc .; A ⁿ⁻ = CO ₃ ²⁻ , OH ⁻ , Cl ⁻ , NO ₃ ⁻ , CO ₃ ²⁻ , COO ^−, etc., m is a positive number of 0 or more, n is 1 to 3, and x is about 0.20 ≦ x ≦ 0.40) It is preferable that it is a compound. A compound obtained by dehydrating this compound by baking at 150 ° C. to 900 ° C., a compound obtained by decomposing an anion in the interlayer, Mg ₆ Al ₂ (OH) ₁₆ CO ₃ .mH ₂ O, which is a natural mineral, etc. You may use as said inorganic compound. The hydrotalcite may be coordinated with a compound having a functional group such as a hydroxyl group, an amino group, a carboxyl group, or a silanol group. You may have organic substance in an interlayer.

The sulfuric acid compound is preferably ettringite, for example.
The phosphoric acid compound is preferably, for example, hydroxyapatite.
The hydroxyapatite is a compound typified by Ca ₁₀ (PO ₄ ) ₆ (OH) ₂ , such as a compound in which the amount of Ca is reduced depending on the preparation conditions, a hydroxyapatite compound into which an element other than Ca is introduced, and the like. You may use as said inorganic compound.

The inorganic compound may be in a dissolved state, a dispersed state such as a colloid, or an insoluble state when it is introduced into an electrolytic solution raw material, an electrolytic solution, a gel electrolyte, etc. Or a negative charge is preferable, and the charged state of the particles can be inferred by measuring the zeta potential. As described later, these inorganic compounds interact with each other by non-covalent bonds such as covalent bonds, coordinate bonds, ionic bonds, hydrogen bonds, π bonds, van der Waals bonds, and agostic interactions with functional groups of polymers. It can also act. When a layered compound such as hydrotalcite is used, a polymer may be formed in the layer, or an organic substance may be included. The inorganic compound is used in a state where a part of its surface is not charged with a positive or negative charge (corresponding to an isoelectric point) when it is introduced into an electrolytic solution raw material, electrolytic solution, gel electrolyte, or the like. May be.

The anion conductive material may be a hydrate when introduced into an electrolyte solution raw material, an electrolyte solution, a gel electrolyte, or the like. By being a hydrate, the conductivity of hydroxide ions and the like involved in the battery reaction can be further increased.

The mass ratio of the inorganic compound is preferably 0.1% by mass or more with respect to 100% by mass of the anion conductive material. More preferably, it is 0.5 mass% or more, More preferably, it is 1 mass% or more, More preferably, it is 3 mass% or more, Most preferably, it is 20 mass% or more. Moreover, it is preferable that it is 99.9 mass% or less. More preferably, it is 99 mass% or less, More preferably, it is 75 mass% or less, More preferably, it is less than 70 mass%, Especially preferably, it is less than 60 mass%, Most preferably, it is 55 mass %.
By making the mass ratio of the inorganic compound within the above range, the effect of the present invention can be exhibited, and the effect of making it difficult to cause cracks in the anion conductive material can be exhibited. Among these, it is particularly preferable that the mass ratio of the layered double hydroxide is within the above range.

The anion conductive material may further contain other components as long as it contains a polymer and an inorganic compound.

The other components are not particularly limited. For example, clay compound; solid solution; alloy; zeolite; halide; carboxylate compound; carbonate compound; hydrogencarbonate compound; nitrate compound; An acid compound, a boric acid compound; a silicic acid compound; an aluminate compound; a sulfide; an onium compound; a salt; and one or more organic compounds may be included. The other components are compounds different from the inorganic compound and the polymer. The above-mentioned other components function to assist ion conductivity or form pores in the anion conductive material described later by being removed using a method such as solvent, heat, baking, electricity, etc. Is also possible.

When other components are used, the mass ratio of the other components is preferably 0.001% by mass or more with respect to 100% by mass of the anion conductive material. More preferably, it is 0.01 mass% or more, More preferably, it is 0.05 mass% or more. Moreover, it is preferable that it is 90 mass% or less. More preferably, it is 70 mass% or less, More preferably, it is 45 mass% or less. Other components may not be contained at all.

The anion conductive material according to the present invention may contain only one kind or two or more kinds of the above-mentioned polymer, inorganic compound and other components. In addition, when two or more types of polymers are included, the mass of the polymer means the total mass of the two or more types of polymers unless otherwise specified. The same applies to the case where two or more inorganic compounds and other components are contained.

The metal-air battery of the present invention is a metal-air battery that has the above-described configuration, can store a large number of negative electrode active materials in the battery, and can stably supply electric energy for a long period of time.

It is the figure which showed an example of the structure of the metal air battery of this invention. FIG. 3 is a diagram illustrating a configuration of a negative electrode in Examples 2 and 3 and Comparative Example 1.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. Unless otherwise specified, “part” means “part by weight” and “%” means “mass%”.

In the following examples and comparative examples, the following were used as the positive electrode for charging, the positive electrode for discharging, the electrolytic solution, and the separator, respectively.
(1) Positive electrode for charging A punched steel plate plated with Ni was used as a positive electrode for charging.
(2) Positive electrode for discharge (air electrode)
Natural graphite and 60% -concentrated tetrafluoroethylene aqueous dispersion (Polyflon D-210C, manufactured by Daikin Industries, Ltd.) mixed at a mass ratio of 9: 1 and pasted into a Ni-plated punched steel sheet by rolling Further, a three-layer structure in which a polypropylene non-woven fabric comes on the electrolyte side and a Teflon (registered trademark) non-woven fabric comes on the air side by pressing to form an air electrode with a separator attached thereto.
(3) Electrolytic solution An 8M concentration KOH aqueous solution was used as the electrolytic solution (zinc oxide was used without being dissolved at all).
(4) Separator 1
Hydrotalcite (trade name: DHT-6, manufactured by Kyowa Chemical Industry Co., Ltd., average particle size is 0.20 μm) and polytetrafluoroethylene aqueous dispersion (trade name: D210C, manufactured by Daikin Industries, Ltd., solid content 60%) Kneader kneading with pure water at a mass ratio of 100: 100: 15 and roll rolling were performed to produce an anion conductive membrane 1 having a thickness of 100 μm.
(5) Separator 2
Hydrotalcite (trade name: DHT-6, manufactured by Kyowa Chemical Industry Co., Ltd., average particle size is 0.20 μm) and an aqueous dispersion of styrene-butadiene copolymer (product name: TRD2001, manufactured by JSR, Tg = -2) ° C, solid content 48%), polytetrafluoroethylene water dispersion (trade name: D210C, manufactured by Daikin Industries, Ltd., solid content 60%), carboxymethylcellulose (trade name: Daicel 1380, manufactured by Daicel Finechem) and pure water Was kneaded at a mass ratio of 100: 100: 5: 3: 15 and roll-rolled to prepare an anion conductive membrane 2 having a thickness of 100 μm.

Example 1
A tinned punched steel sheet (negative electrode current collector) is bent and processed into a bowl shape, and the separator 1 is disposed so as to surround the outer periphery of the bowl, and then metal zinc powder (particle diameter: 50 to 200 μm) is contained therein. 3 g (theoretical capacity 2460 mAh) was used as a zinc negative electrode with a separator attached thereto.
When the zinc negative electrode, the positive electrode for charging, the positive electrode for discharging (air electrode), and the electrolyte were configured as shown in FIG. 1 and the initial discharge capacity was measured, 1837 mAh (discharge efficiency 74. 67%).

Example 2
A punched steel plate plated with tin is inserted into the center of the bowl-shaped negative electrode current collector pasted with the separator prepared in Example 1, and the inside of the bowl is divided into two parts. The initial discharge capacity was measured in the same manner as in Example 1 except that 1.5 g each of 200 μm) (FIG. 2 (a)) was used as the zinc negative electrode with the separator attached thereto, and 2035 mAh (discharge efficiency) 82.72%).

Example 3
After putting foamed copper (pore diameter: about φ1 to 1.5 mm) of the volume corresponding to 30% of the volume inside the basket into the bowl-shaped negative electrode current collector pasted with the separator created in Example 1 The same as in Example 1 except that 3 g (theoretical capacity 2460 mAh) of metal zinc powder (particle size 50 to 200 μm) was introduced into the cage (FIG. 2B) was used as a zinc negative electrode with a separator attached. The initial discharge capacity was measured to find 2263 mAh (discharge efficiency 92%).

Comparative Example 1
After preparing the thing remove | excluding the collector on the bottom face of the bowl-shaped negative electrode collector created in Example 1 (FIG.2 (c)), and arrange | positioning the said separator 1 so that the outer periphery of the bowl may be enclosed After the battery was constructed in the same manner as in FIG. 1, 3 g (theoretical capacity 2460 mAh) of metal zinc powder (particle size 50 to 200 μm) was introduced into the space surrounded by the negative electrode current collector, and the initial discharge capacity was measured. As a result, it was 822 mAh (discharge efficiency 33%).

Examples 4-8
The same battery as in Example 1 (Example 6) and the same battery as in Example 1 except that the separator surrounding the outer periphery of the negative electrode current collector in Example 1 was changed as follows (Examples 4 and 5). 7 and 8) were subjected to a charge / discharge cycle test under the following conditions. The results are shown in Table 1. Note that Celgard 3501 used in Example 4 is a polypropylene microporous membrane manufactured by Celgard, and Nafion used in Example 5 is a perfluorocarbon material manufactured by Sigma-Aldrich.
In Table 1, sudden death refers to a state in which the zinc dendrite reaches the charging electrode and cannot be discharged as a battery.
[Charge / discharge cycle test]
After discharging to a discharge depth of 30%, the cycle of electrically charging the discharged capacity was repeated, and the repeated cycle performance was compared (discharge rate: 70 mAh / cm ² , charge rate: 20 mAh / cm ² ).

From the comparison between Examples 1 to 3 and Comparative Example 1, the negative electrode active material was effectively used for the discharge reaction by using as the negative electrode a negative electrode active material placed in a storage site whose bottom surface was formed of a current collector. It was confirmed that a high discharge capacity can be obtained. It is possible to stably supply electric energy for a long period of time by mounting a large amount of the negative electrode active material on the battery having such a configuration, or by supplying the negative electrode active material from the outside along with discharge.
In addition, from the results of Examples 4 to 8, charging is an electrical energy supply, not a physical energy supply in which a large amount of the negative electrode active material is mounted or a negative electrode active material is supplied from the outside along with discharge. When charging and discharging are repeated, the charge / discharge cycle can be lengthened by using an anion conductive membrane as a separator, and either physical energy supply or electrical energy supply can be used. It was confirmed that electric energy can be supplied stably for a long period of time.

A: Positive electrode for discharge (air electrode) with separator attached
B: Positive electrode for charging C: Negative electrode current collector D: Separator E: Negative electrode active material F: Electrolytic solution G: Battery container

Claims (4)

A metal-air battery having a positive electrode that is an air electrode and a negative electrode using a metal species as a negative electrode active material,
The metal-air battery includes a portion for storing a negative electrode active material,
A metal-air battery, characterized in that at least a part of the bottom surface of the storage part is formed of a current collector. The metal-air battery according to claim 1, wherein the storage part has a supply port through which a negative electrode active material can be supplied from the outside. The metal-air battery according to claim 1 or 2, wherein a separator is disposed between the positive electrode and the negative electrode of the metal-air battery. The metal-air battery according to claim 1, wherein the separator is made of an anion conductive material.

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