JP6560025B2 - Air metal battery - Google Patents

Description

The present invention relates to an air metal battery. More specifically, the present invention relates to an air metal battery such as a tripolar air metal battery having a discharge air electrode and a charge metal electrode as a positive electrode and further having a negative electrode.

Since air metal batteries use oxygen in the air as the positive electrode active material, there is no need to mount the positive electrode active material inside the battery, and therefore the negative electrode active material can be charged in large quantities, thereby increasing the substantial battery capacity. The feature is that it can be done.
A zinc-air battery, which is a kind of air metal battery, has already been used as a primary battery for hearing aids, but there is no example that is distributed in the market as a secondary battery. This is because the charge reaction using the air electrode as the positive electrode is an oxygen generation reaction, so that it is difficult to seal, and carbon used as a catalyst for the positive electrode is oxidized, making it difficult to obtain sufficient performance. Because. Thus, a three-electrode zinc-air battery using an air electrode only as a positive electrode for discharging and separately installing a positive electrode for charging has been proposed (see Patent Document 1). However, it is known that in the negative electrode using a zinc species as an active material, problems such as growth of zinc dendrite and a change in shape of the negative electrode active material layer occur. Since this problem occurs even in a three-pole zinc-air battery, the battery life is very short. For this problem, a device for stably operating the zinc negative electrode has been proposed (see Patent Documents 2 and 3), and a technique for suppressing the zinc dendrite using an anion conductive material has been proposed ( (See Patent Document 4).

JP 2000-133328 A JP 2013-225444 A Japanese Patent Laying-Open No. 2015-225443 JP2015-5493A

In an air zinc battery, which is a kind of air metal battery, it is known that not only the dendrite growth but also the shape change of the negative electrode active material layer occurs in the zinc negative electrode, which is one of the causes of shortening the battery life. Yes. In addition, since the metal that causes the shape change of the negative electrode active material layer is not limited to zinc, it is a common problem for air metal batteries to suppress the shape change of the negative electrode active material layer and extend the life of the air metal battery. It is. As described above, studies have been made for the purpose of obtaining sufficient performance as a zinc-air battery, but it cannot be said that the above technique sufficiently suppresses the change in the shape of the negative electrode active material layer.

The present invention has been made in view of the above situation, and an object of the present invention is to provide an air metal battery in which the shape change of the negative electrode active material layer is effectively suppressed and the life is extended.

The present inventor conducted various studies on an air metal battery in which the shape change of the negative electrode active material layer is effectively suppressed and has a long life, and the discharge air electrode and the negative electrode are in close contact with each other through the separator. In addition, when the battery is configured such that the effective area of the portion where the negative electrode is in contact with the free electrolyte is 50% or less of the total effective area of the negative electrode, the shape change of the negative electrode active material layer is effectively suppressed. The present inventors have found that an air metal battery can have a long life, and have conceived that the above-mentioned problems can be solved brilliantly, and have reached the present invention.

That is, the present invention is an air metal battery having an air electrode as a positive electrode and a metal electrode as a negative electrode, wherein the air electrode and the negative electrode are in close contact with each other via a separator. The air metal battery is characterized in that the effective area of the portion in contact with the electrolytic solution is 50% or less of the entire effective area of the negative electrode.
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.

<Air metal battery>
The air metal battery of the present invention is an air metal battery having an air electrode as a positive electrode and a metal electrode as a negative electrode, wherein the air electrode and the negative electrode are in close contact via a separator, and the negative electrode is free electrolysis. The effective area of the portion in contact with the liquid is 50% or less of the entire effective area of the negative electrode.
Causes of electrode shape change (shape change) include slipping of the negative electrode active material due to gravity and non-uniform precipitation of discharge products (form of active material during discharge). These phenomena greatly depend on the amount of the electrolyte solution in the battery layer, and hardly occur in a battery without a free electrolyte solution. Further, non-uniform precipitation of discharge products (form of active material during discharge) is likely to occur on the side of the negative electrode facing the positive electrode. In the air metal battery of the present invention, since the air electrode and the negative electrode are in close contact with each other through the separator, the negative electrode active material slips off due to gravity from the surface of the negative electrode in close contact with the positive electrode and the separator. Non-uniform precipitation of the discharge product (form of active material during discharge) is effectively suppressed. In addition, since the effective area of the portion where the negative electrode is in contact with the free electrolyte is 50% or less of the total effective area of the negative electrode, the portion of the negative electrode other than the surface in close contact with the positive electrode through the separator The negative electrode active material slipping off due to gravity and non-uniform precipitation of discharge products (form of active material during discharge) are also effectively suppressed.
Furthermore, another cause of the change in shape (shape change) of the electrode is non-uniformity of charge / discharge current in the in-plane direction of the electrode. In order to suppress the shape change, it is important to make the charge / discharge current uniform. If the electrode area is sufficiently large relative to the distance between the electrodes, a parallel electric field is formed between the electrodes. It is important to form this parallel electric field for the uniformity of the charge / discharge reaction. The air electrode and the negative electrode are in close contact with each other through the separator, so that the effective area of the air electrode and the negative electrode Since the distance is reduced and a parallel electric field is easily formed, the shape change is effectively suppressed also from this point.
In the present invention, the effective area of the electrode means the area of the electrode surface that can function as an electrode. For example, a part of the electrode active material layer is covered with an insulating paint or film. If there is a part, the part is not included in the effective area.

Further, the air metal battery of the present invention has the following effects. The separator and electrolyte present between the air electrode and the negative electrode all have resistance to ion movement, but the air electrode and the negative electrode are in close contact with each other via the separator, so Therefore, only the electrolyte contained in the separator exists. In addition, since the separator can also be made thin, the resistance of ion movement between the air electrode and the negative electrode is reduced, and a battery having a large output (voltage) can be obtained.
In the present invention, the free electrolytic solution means an electrolytic solution in a state where it can freely move, and an electrolytic solution having a restriction on free movement like the electrolytic solution contained in the separator is a free electrolytic solution. Not included in the liquid.

In the negative electrode, the effective area of the portion in contact with the free electrolyte is preferably 50% or less of the total effective area of the negative electrode, more preferably 30% or less, most preferably 0%, That is, there is no portion in contact with the free electrolyte.
Here, the ratio of the effective area of the portion of the negative electrode that is in contact with the free electrolyte is a ratio to the effective area of the entire surface of the negative electrode active material layer. When the negative electrode is one in which a negative electrode active material layer is formed on both sides of the current collector, it means the total effective area of the surfaces of the negative electrode active material layer on both sides of the current collector.
In the present invention, the effective area of the electrode can be calculated after measuring the sides with a ruler or caliper.

The air zinc battery of the present invention is a three-pole air metal battery having a discharge air electrode and a charge metal electrode as a positive electrode, even if it is a two-pole air metal battery having an air electrode and a negative electrode. However, the technical significance of the configuration of the present invention is more exhibited in the case of a tripolar air metal battery in which a free electrolyte is particularly necessary. In the case of a three-pole type air metal battery, the above-described effects can be exhibited if the discharge air electrode and the negative electrode are in close contact with each other via a separator.
That is, the air metal battery is a three-electrode air metal battery having a discharge air electrode and a charge metal electrode as a positive electrode, and the air metal battery has a discharge air electrode and a negative electrode as separators. A preferred embodiment of the air metal battery of the present invention is that the effective area of the portion where the negative electrode and the free electrolyte are in contact is 50% or less of the total effective area of the negative electrode. It is one of.

In the three-electrode air metal battery of the present invention, the discharge positive electrode preferably has an effective area of the portion in contact with the free electrolyte of 5% or less of the total effective area of the discharge positive electrode. The air electrode needs to have a three-layer interface of a metal, air, and electrolyte that serve as a catalyst for the air electrode. If there is a part in contact with the free electrolyte in the air electrode, the air electrode gets wet with the electrolyte and the three-layer interface disappears (sink of the air electrode), but only with the electrolyte contained in the separator. In the contacted portion, the sinking of the air electrode is suppressed and a three-layer interface can be formed. In addition, leakage of the electrolytic solution can be suppressed. Of the positive electrode for discharge, the effective area of the portion in contact with the free electrolyte is more preferably 3% or less of the total effective area of the positive electrode for discharge, most preferably 0%, that is, for discharge There is no portion in contact with the free electrolyte in the effective area of the positive electrode.
Here, the whole effective area of the positive electrode for discharge means the sum of the areas of those portions when there are portions that can function as electrodes on both surfaces of the positive electrode for discharge.

In the above-described three-electrode air metal battery, it is preferable that the negative electrode is in close contact with the separator on the surface opposite to the surface facing the discharge air electrode. As a result, even on the surface of the negative electrode opposite to the surface facing the discharge air electrode, the portion in close contact with the separator is not in contact with the free electrolyte, and the negative electrode active material slides down due to gravity. And the non-uniform precipitation of discharge products (form of active material during discharge) can be more effectively suppressed, and the growth of dendrites when zinc species and cadmium species are used as active materials can also be suppressed. .

In the three-pole air metal battery, the negative electrode and the metal electrode for charging are in close contact via a separator is one of the preferred forms of the three-pole air metal battery of the present invention. As a result, the distance between the negative electrode and the metal electrode for charging can be sufficiently close to the effective area between the negative electrode and the metal electrode for charging, and a parallel electric field is generated between the negative electrode and the metal electrode for charging. By being easily formed, the charge / discharge current in the in-plane direction of the electrode becomes sufficiently uniform, and the shape change on the surface facing the metal electrode for charging of the negative electrode is also effectively suppressed. Furthermore, the growth of dendrites when zinc species or cadmium species are used as the negative electrode active material can be more effectively suppressed.
In the case of a bipolar air metal battery, the growth of dendrites is effectively suppressed because the air electrode and the negative electrode are in close contact via the separator.

FIG. 1 shows an example of a preferred embodiment of the air metal battery of the present invention. This air metal battery is a three-pole type air metal battery having a discharge air electrode and a charge metal electrode as a positive electrode, and the discharge air electrode on the side facing the negative electrode and the discharge air. The entire negative electrode on the side facing the electrode is in close contact with the separator, and the entire negative electrode on the side facing the discharge positive electrode is also in close contact with the separator. Neither the discharge air electrode nor the negative electrode is in contact with the free electrolyte, and the free electrolyte exists only around the positive electrode for charging. This air metal battery has a large capacity by arranging a negative electrolyte and a discharge air electrode on the left and right sides of a free electrolyte placed in the center and a positive electrode for charging.
Yet another preferred form is shown in FIG. 2 is different from the embodiment of FIG. 1 in that the surface of the negative electrode facing the discharge positive electrode and the charge positive electrode are in close contact with each other through a separator. By adopting the form of FIG. 2, the shape change on the side of the surface facing the metal electrode for charging the negative electrode is effectively suppressed as compared with the battery of the form of FIG. 1.

<Negative electrode>
The negative electrode constituting the air metal battery of the present invention is not particularly limited as long as it can function as the negative electrode of the air metal battery, and is not limited to cadmium species / lithium species / sodium species / magnesium species / lead species / zinc species. -What is usually used as a negative electrode active material of a battery, such as a tin species, a silicon-containing material, a hydrogen storage alloy material, and a noble metal material such as platinum, can be used as a negative electrode active material. As described above, since the growth of dendrites can be effectively suppressed by installing a separator between the negative electrode and the positive electrode, among the above, zinc species or cadmium species are preferable as the negative electrode.
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 preferably has a negative electrode active material layer formed on a 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 auxiliary is within such a range, better battery performance is exhibited when the electrode of the present invention is used for a battery. 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.

The current collector constituting the negative electrode is not particularly limited, (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-resistant 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 with conductivity ; Copper foil, copper mesh (expanded metal), foamed copper, punched copper, brass and other copper alloys, brass foil, etc. with addition of Ni, Zn, Sn, Pb, Hg, Bi, In, Tl, brass, etc. 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, 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.

<Positive electrode for charging>
Although it does not restrict | limit especially as long as it can function as a positive electrode for charge as a positive electrode for charge which comprises the electrode for air metal batteries of a 3 pole system of this invention, It is perpendicular | vertical with respect to the surface facing a negative electrode. A structure or material capable of conducting ions in the 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 air metal battery of the present invention (in the case of the three-pole system, the discharge air electrode) is not particularly limited as long as it functions as an air electrode, but may contain an air electrode catalyst. It is more preferable that an 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 electrolyte constituting the air metal battery of the present invention, those commonly used as an electrolyte 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 polyethylene And glycols. The organic solvent electrolyte 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>
The thickness of the separator constituting the air metal battery of the present invention 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.

Examples of the separator include 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, hydroxyalkylcellulose, carboxymethylcellulose. , Polyvinyl alcohol-containing polymer, cellophane, polystyrene-containing aromatic ring-containing polymer, polyacrylonitrile-containing polymer, polyacrylamide-containing polymer, polyvinyl fluoride-containing polymer-containing halogen-containing polymer, polyamide-containing polymer, polyimide-containing polymer , Nylon and other ester moiety-containing polymers, poly (meth) acrylic acid moiety-containing polymers, poly (meth) acrylate Oxalate-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 and carbamide group-containing polymer such as polyurethane, 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, cyclic hydrocarbon group-containing polymer , Ether group-containing polymers, inorganic materials such as ceramics, and nonporous membranes formed of materials having ion conductivity.

Among the above separators, the separator in the present invention is preferably an anion conductive membrane. By using an anion conductive membrane as a separator, it is possible to sufficiently suppress the growth of dendrites such as zinc while ensuring good permeability of anions necessary for electrode reaction.
In the three-electrode air metal battery of the present invention, the discharge air electrode and the negative electrode are in close contact with each other through the separator, and the negative electrode and the charge metal electrode are in close contact with each other through the separator. However, when the air metal battery of the present invention has a separator between the discharge air electrode and the negative electrode and between the negative electrode and the metal electrode for charging, at least one of these separators. Is preferably an anion conductive membrane. More preferably, both of these separators are anion conductive membranes.
Thus, including an anion conductive membrane as a separator is one of the preferred embodiments of the air metal battery of the present invention.
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.
(Japanese translations of PCT publication No. 2014-503689, JP2013-145758, JP2013-091598, JP2014-011000, JP2013-211201)

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 three-electrode system, the positive electrode for charging), the air metal 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 contained in the anion conductive material include hydrocarbon moiety-containing polymers such as polyethylene and polypropylene, aromatic group-containing polymers typified by polystyrene, etc .; ether group-containing polymers typified by alkylene glycol, etc .; polyvinyl alcohol and poly Hydroxyl group-containing polymers represented by (α-hydroxymethyl acrylate), etc .; polyamide, nylon, polyacrylamide, amide group-containing polymers represented by N-substituted polyacrylamide, etc .; represented by polymaleimide, etc. Imido group-containing polymer; carboxyl group-containing polymer represented by poly (meth) acrylic acid, polymaleic acid, polyitaconic acid, polymethylene glutaric acid, etc .; poly (meth) acrylate, polymaleate, polyitaconate, poly Carboxylic acid group-containing polymers such as methylene glutarate; halogen-containing polymers such as polyvinyl chloride, polyvinylidene fluoride, and polytetrafluoroethylene; polymers bonded by opening of epoxy groups such as epoxy resins; sulfones AR ¹ R ² R ³ B (A represents N or P. B represents an anion such as a halogen anion or OH ^−, and R ¹ , R ² , and R ³ are the same or different. And 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 may combine to form a ring structure.) Quaternary ammonium salt or quaternary phosphonium salt-containing polymer represented by the polymer to which the group represented by is attached; used for cation / anion exchange membranes, etc. Natural rubber; artificial rubber typified by styrene butadiene rubber (SBR), etc .; cellulose, cellulose acetate, hydroxyalkyl cellulose (for example, hydroxyethyl cellulose), carboxymethyl cellulose, chitin, chitosan, alginic acid (salt) Sugar group represented by polyethylene; amino group-containing polymer represented by polyethyleneimine; carbamate group site-containing polymer; carbamide group site-containing polymer; epoxy group site-containing polymer; heterocycle and / or ionized heterocycle site-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)
(Wherein M ¹ = Mg, Fe, Zn, Ca, Li, Ni, Co, Cu, etc .; M ² = Al, Fe, Mn, etc .; A = CO ₃ ²⁻ etc., m is a positive number of 0 or more, n is preferably 2 or 3, and x is preferably a compound represented by about 0.20 ≦ x ≦ 0.40. This compound is a compound dehydrated by firing at 150 ° C. to 900 ° C., a compound obtained by decomposing an anion in the interlayer, a compound obtained by exchanging the anion in the interlayer with a hydroxide ion, or a natural mineral. Mg ₆ Al ₂ (OH) ₁₆ CO ₃ .mH ₂ O or the like may be used as the 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% Is less than.
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 air metal battery of the present invention is an air metal battery having the above-described configuration, in which the shape change of the negative electrode active material layer is effectively suppressed and the life is extended.

It is the conceptual diagram which showed an example of the suitable form of the air metal battery of this invention. It is the conceptual diagram which showed an example of the suitable form of the air metal battery of this invention. 4 is a conceptual diagram showing the structure of a comparative air metal battery manufactured in Comparative Example 1. FIG.

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%”.

Production Example 1 (Production of zinc negative electrode)
A paste prepared by mixing 60 g of a polytetrafluoroethylene aqueous dispersion (Polyflon D-210C, manufactured by Daikin) and 60 g of zinc oxide (average particle size: 1 μm) with a thickness of a tin-plated punched steel sheet by rolling. A zinc negative electrode having a thickness of 2 mm was obtained. The effective area (single side) of the zinc negative electrode was 4 cm ² .

Production Example 2 (Production of positive electrode for discharge)
Natural graphite and a 60% concentration tetrafluoroethylene aqueous dispersion (Polyflon D-210C, manufactured by Daikin) were mixed at a mass ratio of 9: 1 and pasted into a Ni-plated punched steel sheet by rolling. Thus, an air electrode (discharge positive electrode) was obtained. The effective area (one side) of the air electrode was 4 cm ² .

Example 1 (Production and Evaluation of Air Metal Battery 1)
Using the zinc negative electrode produced in Production Example 1, the discharge positive electrode produced in Production Example 2, and the Ni-plated punched steel sheet (effective area 1 cm ² of the surface (one side) facing the negative electrode) as the positive electrode for charging, A battery having a structure as shown in FIG. 1 was constructed using a hydrophilic microporous membrane having a thickness of 0.1 mm as a separator and an 8M KOH aqueous solution saturated with zinc oxide as an electrolyte. In this battery, the whole air electrode on the side facing the negative electrode and the whole negative electrode on the side facing the air electrode are in close contact with each other through the separator, and the air electrode is not in contact with the free electrolyte. . In addition, the entire negative electrode facing the positive electrode for charging is in close contact with the separator, and a free electrolyte exists only around the positive electrode for charging. In this battery, an air electrode and a negative electrode are arranged on the left and right with a free electrolyte placed in the center and a positive electrode for charging.
The air metal battery was charged with a charging current of 30 mA / cm ² for 1 hour, then discharged with the same current value using an air electrode (positive electrode for discharge), and this was tested as one cycle. As a result, the charge / discharge efficiency was good even after 50 cycles. No shape change or dendrite growth was observed on the negative electrode after 50 cycles.

Example 2 (Production and Evaluation of Air Metal Battery 2)
A battery of only the left side portion was formed from the free electrolyte in the center of the air metal battery 1 of Example 1 and the positive electrode for charging, and the same cycle test as in Example 1 was performed. As a result, the charge / discharge efficiency was good even after 50 cycles. No shape change or dendrite growth was observed on the negative electrode after 50 cycles.

Comparative Example 1 (Production and evaluation of comparative air metal battery)
The zinc negative electrode produced in Production Example 1, the positive electrode for discharge produced in Production Example 2, and the same Ni-plated punched steel plate as that in Example 1 were used as the positive electrode for charging. A battery having a structure as shown in FIG. 3 was constructed using an 8 M aqueous KOH solution saturated with zinc oxide as an electrolyte using a 1 mm hydrophilic microporous membrane. In this battery, the positive electrode for charging was disposed in the center of the zinc negative electrode, and a free electrolyte was present not only around the positive electrode for charging but also around the zinc negative electrode.
A cycle test similar to that in Example 1 was performed on this comparative air metal battery. As a result, the active material accumulated at the bottom of the zinc electrode at the 10th cycle, and the electrode shape changed greatly. At 20 cycles, the zinc electrode contacted the charging electrode, resulting in poor charging.

A: Negative electrode B: Positive electrode for charging C: Positive electrode for discharging (air electrode)
D: Electrolyte E: Separator F: Electrode fixing member

Claims (3)

It possesses an air electrode for discharge and a metal electrode for charging as a positive electrode, an air-metal batteries of three-pole type having a metallic electrode and a negative electrode,
In the air metal battery, the discharge air electrode and the negative electrode are in close contact with each other through the separator, and the charge metal electrode is in contact with the free electrolyte.
Negative electrode and der than 50% of the total effective area of the effective area negative electrode portion free and electrolyte are in contact is,
An air metal battery, characterized in that a negative electrode and a discharge air electrode are arranged on the left and right sides of a free electrolyte and a charging metal electrode, respectively . The air metal battery according to claim 1 , wherein the negative electrode and the charging metal electrode are in close contact with each other through a separator. The air-metal batteries are air metal battery according to claim 1 or 2, characterized in that it comprises an anion conducting membrane as a separator.

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