JP2021111574A - Metal air battery - Google Patents

Abstract

To provide a metal air battery which can suppress the corrosion of a positive electrode current collector, and achieve a long life.SOLUTION: A metal air battery according to the present invention comprises: a negative electrode 1; an air electrode 3; and an electrolyte 2 interposed between the negative electrode 1 and the air electrode 3. In the metal air battery, a positive electrode current collector contains at least one kind selected from a group consisting of titanium metal, molybdenum metal, a nickel-based alloy, tungsten metal, zirconium metal, tantalum metal and a carbon-based material; an air electrode catalyst material contains at least one kind selected from a group consisting of a non-oxide ceramic, a carbon-based material and a composite oxide. Further, the air electrode catalyst material is supported on a least one kind selected from a group consisting of a noble metal-based nano colloid, a carbon quantum dot, a graphene quantum dot, a metal organic structure, a metal organic structure (MOF)-originating carbon-based material, and a metal organic structure (MOF)-originating oxide-based material.SELECTED DRAWING: Figure 1

Description

The present invention relates to a metal-air battery having a negative electrode, an air electrode, and an electrolyte interposed between the negative electrode and the air electrode.

A general metal-air battery uses a metal as a negative electrode, a liquid electrolyte as an electrolyte, and an air electrode as a positive electrode, and uses oxygen in the air as a positive electrode active material. Since such a metal-air battery utilizes oxygen that is inexhaustibly present in the air as the positive electrode active material, it is not necessary to incorporate the positive electrode active material in the battery. Further, since most of the space in the battery container can be filled with the negative electrode active material, in principle, it has the highest energy density in the chemical battery. Therefore, it can be expected that the size and weight of the battery will be reduced and the capacity will be increased.

In a metal-air battery, at the time of discharge, oxygen is reduced at the air electrode and metal is dissolved at the negative electrode with electron emission. For example, the reaction formula at the time of discharging Al and air in the case of an aluminum-air battery using aluminum for the negative electrode is shown below.

[At the time of discharge]
Negative electrode: Al + 3OH ⁻ → Al (OH) ₃ + 3e ⁻
_{Cathode: 3 / 4O 2 + 3 /} 2H 2 O + 3e - → 3OH -
In recent years, as an air battery having a low risk of ignition and excellent safety, an air battery using an ionic liquid as an electrolytic solution has also been proposed. For example, Patent Document 1 discloses an air battery using an ionic liquid as an electrolytic solution, and Example 1 uses 1-ethyl 3-methylimidazolium chloride (EMIC) and anhydrous AlCl ₃ . An electrolytic solution in an ionic liquid is disclosed.

JP-A-2010-129495

However, for example, when an ionic liquid as in Example 1 of Patent Document 1 is used as an electrolytic solution, it has a relatively wide potential window, but contains a corrosive component such _{as AlCl 3 as a metal salt.} Therefore, it was found that even if a general positive electrode current collector (for example, stainless mesh, nickel mesh, etc.) is used, the positive electrode current collector rusts, which adversely affects the battery life and battery characteristics. .. Furthermore, according to the study by the present inventors, even when a deep eutectic solvent is used instead of the ionic liquid, corrosion can be suppressed to some extent, but the corrosiveness of _{AlCl 3 and the like is similar to that of the ionic liquid.} Since it contains a certain component, it has been found that repeated use causes the same problem as described above.

Therefore, an object of the present invention is to suppress corrosion of the positive electrode current collector and prolong the life of the battery even if the electrolytic solution contains a corrosive component. Furthermore, an object of the present invention is to increase the redox reaction and improve electrical characteristics such as battery capacity.

As a result of diligent research to achieve the above object, the present inventors have made a positive electrode current collector containing a corrosion-resistant material instead of a conventional general positive electrode current collector in a metal-air battery, and further, a noble metal system. By using an air electrode catalyst material carrying nanocolloids or the like, even if the electrolytic solution contains corrosive components, the corrosion of the positive electrode current collector can be suppressed and the battery can last a long time. Furthermore, they have found that the redox reaction can be increased to improve the electrical characteristics such as the battery capacity, and have completed the present invention.

That is, the metal-air battery of the present invention is a metal-air battery having a negative electrode, an air electrode, and an electrolyte interposed between the negative electrode and the air electrode.
The air electrode has a catalyst layer containing an air electrode catalyst material and a positive electrode current collector.
The positive electrode current collector contains at least one selected from the group consisting of titanium metal, molybdenum metal, nickel alloy, tungsten metal, zirconium metal, tantalum metal and carbon metal.
The air electrode catalyst material contains at least one selected from the group consisting of non-oxide ceramics, carbon-based materials, and composite oxides.
Further, the air electrode catalyst material includes a noble metal nanocolloid, a carbon quantum dot, a graphene quantum dot, a metal organic structure (MOF), a carbon material derived from the metal organic structure (MOF), and a metal organic structure (MOF). ) Is a metal-air battery supported by at least one selected from the group consisting of oxide-based materials derived from). In a metal-air battery, instead of a conventional general positive electrode current collector, a positive electrode current collector containing a corrosion-resistant material is used, and an air electrode catalyst material carrying a noble metal-based nanocolloid or the like is used for electrolysis. Even if the liquid contains corrosive components, the corrosion of the positive electrode current collector can be suppressed, the battery can last a long time, and the redox reaction can be increased to increase the electrical characteristics such as the battery capacity. Can be improved.

In the metal-air battery of the present invention, the positive electrode current collector preferably has a porous structure. Such a structure is excellent in current collection efficiency and is advantageous in realizing the action and effect of the present invention.

In the metal-air battery of the present invention, the non-oxide ceramic preferably contains metal carbides, nitrides, borides, oxynitrides, carbonitrides, or silicides. As a result, the formation of by-products is suppressed, which is advantageous in realizing the effects of the present invention.

In the metal-air battery of the present invention, the carbon-based material preferably contains carbon nanotubes, graphene, graphite, activated carbon, or a carbon alloy. This is excellent in oxygen reduction ability and conductivity, and is advantageous in realizing the action and effect of the present invention.

In the metal-air battery of the present invention, the composite oxide is preferably a perovskite-type composite oxide. As a result, it is resistant to repeated charging and discharging, and the use of a secondary battery is optimized, which is advantageous in realizing the effects of the present invention.

In the metal-air battery of the present invention, the electrolyte preferably contains an ionic liquid or a deep eutectic solvent. By using an ionic liquid, it has a wide potential window and is easy to use for various types of metal-air batteries. On the other hand, by using a deep eutectic solvent, an electrolyte having a higher environmental affinity can be obtained, and safety can be further improved.

In the metal-air battery of the present invention, the electrolyte is preferably in a solid state. Thereby, in addition to the above effects, it is possible to further prevent the volatilization of the electrolyte and prevent the liquid leakage of the electrolyte.

In the metal-air battery of the present invention, the negative electrode preferably contains aluminum. As a result, aluminum is abundant in resources, inexpensive, and environmentally friendly, so that a versatile aluminum-air battery can be manufactured.

The metal-air battery of the present invention is preferably a metal-air battery for a primary battery or a secondary battery. Thereby, it is possible to provide a battery having a high volume energy density as a metal-air battery for a primary battery or a secondary battery.

It is a schematic diagram which shows an example of the metal-air battery of this invention. It is a figure which shows the cyclic voltammogram of the metal-air battery of Example 1. It is a figure which shows the charge / discharge curve of the metal-air battery of Example 1.

Hereinafter, embodiments of the metal-air battery of the present invention will be described, but the present invention is not limited to the following embodiments, and the present invention shall be carried out with appropriate modifications within the scope of the object of the present invention. Can be done. In addition, in a part or all of the figure, a part unnecessary for explanation is omitted, and there is a part shown by enlargement or reduction for facilitation of explanation. The terms indicating the positional relationship such as top and bottom are used merely for the sake of facilitation of explanation, and there is no intention of limiting the configuration of the present invention.

<Metal-air battery>
FIG. 1 is a diagram showing the present embodiment which is an example of a preferable embodiment in the metal-air battery of the present invention. As shown in FIG. 1, the metal-air battery of the present invention has a negative electrode 1, an air electrode 3, and an electrolyte 2 interposed between the negative electrode 1 and the air electrode 3. The metal-air battery of the present invention is based on a structure in which the negative electrode 1 and the air electrode 3 sandwich the electrolyte 2, and other configurations can be obtained without particular limitation on the conventionally well-known configurations.

For example, the negative electrode 1 can be made of a metal plate such as an aluminum plate. The electrolyte 2 may have a structure in which a material functioning as a separator holds the electrolytic solution or the electrolytic solution is partitioned by the separator. Further, the air electrode 3 can have a structure using a non-air electrode catalyst material in which a noble metal-based nanocolloid or the like is supported on a metal perforated plate such as a metal mesh having corrosion resistance. Further, an ionic conductor such as a solid electrolyte may be interposed between the negative electrode 1 and the air electrode 3. Hereinafter, each configuration of the metal-air battery of the present invention will be described.

<Negative electrode>
The negative electrode in the present invention preferably contains aluminum from the viewpoint of increasing the theoretical energy density among the metals that generate metal ions and electrons by the oxidation reaction and act as the negative electrode active material. Examples of those containing aluminum include pure aluminum metals and aluminum alloys. For example, examples of pure aluminum metal include so-called pure aluminum, which is mainly composed of aluminum and has an Al component of 99% or more. For example, as the aluminum alloy, aluminum is mainly used, and Li, Mg, Sn, Zn, In, Mn, Ga, Bi, Fe and the like can be alloyed with aluminum alone or in combination of two or more. Among them, aluminum alloys such as Al-Li, Al-Mg, Al-Sn, and Al-Zn are particularly preferable because they give a high battery voltage. As described above, the metal-air battery of the present invention is preferably an aluminum-air battery containing mainly aluminum in the negative electrode.

The material used for the negative electrode (for example, aluminum) can act as a negative electrode active material capable of releasing and taking in metal ions. The negative electrode may contain only the material, or may contain at least one of a conductive material and a binder in addition to the material. For example, when the material is foil-shaped, plate-shaped, mesh (grid) -shaped, or the like, it can be a negative electrode containing only the material. On the other hand, when the material is in the form of powder or the like, it can be a negative electrode containing the material and a binder. Since the conductive material and the binder are the same as those described in the section of "air electrode", the description thereof is omitted here.

The negative electrode may include a negative electrode current collector that collects current from the negative electrode, if necessary. The material of the negative electrode current collector is not particularly limited as long as it has conductivity, and examples thereof include copper, stainless steel, nickel, and carbon. Examples of the shape of the negative electrode current collector include a foil shape, a plate shape, a mesh (grid) shape, and the like. In the present invention, the battery case may also have the function of the negative electrode current collector. The negative electrode can also serve as a negative electrode current collector, but if a current collector or a battery case is considered, this area may also come into contact with the electrolytic solution, so that it has corrosion resistance as a material for the negative electrode current collector. A material (for example, the corrosion-resistant material described in the positive electrode current collector) can also be used.

The thickness of the negative electrode current collector varies depending on the application of the metal-air battery and the like, but is preferably in the range of, for example, 10 μm to 1000 μm, particularly preferably in the range of 20 μm to 400 μm.

The method for producing the negative electrode is not particularly limited, and a well-known method can be used. For example, a commercially available plate-shaped material (for example, the material as described above) can be used as it is. As a commercially available plate-shaped material, for example, when aluminum is used, 99% or more of the material is Al component, such as A1100, A1050, A1085, etc., and a material called pure aluminum is formed into a predetermined shape (for example,). It can be cut into a circle, tape, plate, etc. and used as it is. Further, for example, the foil-shaped metal material and the negative electrode current collector can be superposed and pressurized. Further, as another method, a method of preparing a negative electrode material mixture containing a negative electrode active material and a binder and the like, applying the mixture onto a negative electrode current collector, and drying the mixture can be mentioned.

The thickness of the negative electrode varies depending on the application of the metal-air battery, etc., but when the material is foil-shaped, plate-shaped, etc., for example, it should be in the range of 2 μm to 10 mm, particularly in the range of 5 μm to 2 mm. Is preferable.

<Air pole>
The air electrode in the present invention has a catalyst layer containing an air electrode catalyst material and a positive electrode current collector. The catalyst layer can have a role of absorbing oxygen from the air and reacting it with oxygen. As the air electrode catalyst material, any of various catalysts can be used as long as it is a substance that receives electrons generated at the negative electrode and reduces oxygen. For example, the air electrode catalyst material is a carbon-based material such as carrying an alloy with a noble metal such as platinum, another noble metal or a transition metal such as nickel or cobalt, an oxide of a transition metal such as nickel or cobalt, Mn ₂ O. _3, Mn ₃ O manganese lower oxides such as _4, non-oxide ceramics, is preferably at least one selected carbon-based material, and from the group consisting of composite oxides. From the viewpoint of oxygen reducing ability and conductivity, the air electrode catalyst material preferably contains at least one selected from the group consisting of non-oxide ceramics, carbon-based materials, and composite oxides. From the viewpoint of increasing the redox capacity, the air electrode catalyst material is a noble metal nanocolloid, a carbon quantum dot, a graphene quantum dot, a metal organic structure (MOF), a carbon material derived from the metal organic structure (MOF), and the like. It is preferably supported by at least one selected from the group consisting of oxide-based materials derived from metal organic structures (MOF).

The composite oxide in the present invention is preferably a perovskite-type composite oxide from the viewpoint of charge / discharge characteristics. _{For example, as a perovskite-type composite oxide, La (1-x)} A _x MnO ₃ (0.05 <x <0.95; A) from the viewpoint of being resistant to repeated charging and discharging and being optimally used as a secondary battery. = Ca, Sr, Ba) and other perovskite-type composite oxides are preferable, and LaSrCoO _3- based composite oxides (LSC), LaSrMnO _3- based composite oxides (LSM), and LaSrCoFeO _3- based composite oxides are preferable. (LSCF), BaSrCoFeO _3- based composite oxide (BSCF), BaLaCoO _3- based composite oxide (BLC), LaSrFeO _3- based composite oxide (LSF), PrSrCoFeO _3- based composite oxide (PSCF), or LaSrMnO _3- based composite oxide Things (LSM) and the like can be mentioned.

The perovskite-type compound can be produced by a well-known method, and both natural products and synthetic products can be obtained as commercial products. The commercially available product can be used as it is, or if necessary, it can be pulverized by a well-known method such as dry pulverization or wet pulverization to adjust the particle size before use.

In the present invention, the "non-oxide ceramic" refers to a ceramic other than the oxide ceramic composed of only metal oxides. Examples of the non-oxide ceramic include metal carbides, nitrides, borides, oxynitrides, carbonitrides, silicides and the like. In addition, these non-oxide ceramics can be used alone or in combination of two or more. Specifically, from the viewpoint of suppressing the formation of by-products at the air electrode, metal carbides or nitrides are preferable, and at least one selected from the group consisting of titanium nitride and titanium carbide is preferable.

The carbon-based material in the present invention is not particularly limited, and a substance mainly composed of carbon atoms can be used. For example, as carbon-based materials, carbon fine particles such as carbon black, single-walled carbon nanotubes having a hollow cylindrical structure with one hexagonal mesh graphene sheet, multi-walled carbon nanotubes composed of a large number of graphene sheets, etc. Examples thereof include carbon nanotubes, carbon fibers such as carbon fibers, layered carbons such as graphite, sheet-like carbons such as graphene, activated carbon, and carbon alloys. The carbon-based material may be conductive or non-conductive. The carbon-based material in the present invention preferably contains carbon nanotubes, graphene, graphite, activated carbon, or carbon alloy from the viewpoint of oxygen reducing ability and conductivity. In addition, these carbon materials can be used alone or in combination of two or more.

Here, the carbon alloy is a carbon-based material doped with a heteroatom (for example, N, S, P, B, Fe, Co, Cu, Mn, Ni, Ti, Cr, V, etc.). In addition, carbon alloy is "a material consisting of a multi-component system mainly composed of aggregates of carbon atoms and having physical and chemical interactions between their constituent units. However, carbon having different mixed orbitals is a material. Think of it as a different component system, "as defined by the Society of Carbon Materials. For example, examples of the carbon alloy include a carbon alloy doped with a metal such as Ni, Co, Fe, Mn, Ti, Cr, and V and nitrogen, and a carbon alloy doped with N, B, P, and S.

The carbon alloy can be produced by a well-known method. Specific carbon alloys include, for example, N (nitrosulfur) doped carbon, B (boron) doped carbon, BN (boron, nitrogen) doped carbon, SN (sulfur, nitrogen) doped carbon, and PBN (phosphorus, boron, nitrogen) doped. Examples thereof include carbon and NSP (nitrosulfur, sulfur, phosphorus) doped carbon.

The content of the air electrode catalyst material is not particularly limited, but is preferably 30 to 95% by mass, for example, from the viewpoint of improving the battery characteristics when the total mass of the catalyst layer is 100% by mass. In particular, it is preferably 40 to 80% by mass.

Further, the air electrode catalyst material includes a noble metal nanocolloid, a carbon quantum dot, a graphene quantum dot, a metal organic structure (MOF), a carbon material derived from the metal organic structure (MOF), and a metal organic structure (MOF). ) Is preferably supported by at least one selected from the group consisting of oxide-based materials derived from).

Examples of the noble metal nanocolloid include gold (Au), silver (Ag), platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru), and osmium (Os). Examples include nanocolloids of precious metals. From the viewpoint of electrical characteristics, Pt nanocolloids are preferably used as the noble metal nanocolloids. For example, a noble metal such as platinum can be supported on a carbon-based material such as graphite or carbon nanotubes in order to promote a chemical reaction. Depending on the application and the type of substrate, noble metal-based nanocolloids can be used in physical vapor deposition (PVD methods) such as vacuum vapor deposition and sputtering, electroplating methods, electroless plating methods, and metal colloid supporting methods. It is produced by using a method appropriately selected from the wet methods. Among these, the metal colloid supporting method is a method of supporting metal nanocolloid particles on a substrate by a coating method such as immersion, spraying, or evaporation to dryness using a metal nanocolloid liquid containing metal nanocolloid fine particles. It has advantages such as easy operation and no need for expensive coating equipment. Further, for example, platinum can be supported on a carbon-based material or the like by adding Pt nanocolloids and ultrasonically dispersing them. The amount of such a noble metal supported is usually 0.01 to 5% by mass, preferably 0.05 to 1% by mass in 100% by mass of the air electrode catalyst material. The average primary particle size of the supported noble metal is usually in the range of 4 to 100 nm. Here, the nanocolloid refers to colloidal particles having an average primary particle diameter of less than 100 nm.

Quantum dots are ultrafine nanoparticles usually having a diameter of about 0.5 to about 10 nm, particularly about 2 to 10 nm, and have a structure that three-dimensionally confine electrons. The carbon quantum dots in the present invention are, for example, a production method in which a carbon target is laser ablated and then chemically treated, a method for producing from candle soot, a production method in which graphite oxide is chemically treated, and a fullerene conversion reaction. It can be produced by a known production method such as a method of producing from, a hydrothermal synthesis, a sorbothermal method, a production method of chemically treating a cheaper carbon raw material such as carbon fiber and activated carbon. For example, examples of quantum dots include carbon quantum dots and graphene quantum dots.

The method for supporting carbon quantum dots on a carbon-based material or the like and the amount of carbon quantum dots supported are 0.1 to 100% by mass in 100% by mass of the air electrode catalyst material, as described in Comparative Examples and Examples. Similarly, as a catalyst material, a mixture of these carbon quantum dots can be combined with an aqueous emulsion of PVDF, N-methylpyrrolidone, or PTFE, CMC, or SBR to create an air electrode.

Graphene quantum dots are roughly divided into two types of manufacturing methods, a top-down method and a bottom-up method. In the top-down method, an oxidizing agent is allowed to act on the raw materials graphite and carbon fibers to form fine particles (fine discs) as graphene oxide. The graphene oxide fine particles (fine discs) that have been cut out are used as they are or reduced to form graphene quantum dots. On the other hand, the bottom-up method uses low-molecular-weight saccharides and amino acids as raw materials for condensation. Although it is a method of producing graphene quantum dots repeatedly, it can be produced by a known production method.

The method for supporting graphene quantum dots on a carbon-based material or the like and the amount of graphene quantum dots supported are 0.1 to 100% by mass in 100% by mass of the air electrode catalyst material, as described in Comparative Examples and Examples. Similarly, as a catalyst material, a mixture of graphene quantum dots can be combined with an aqueous emulsion of PVDF, N-methylpyrrolidone, or PTFE, CMC, or SBR to create an air electrode.

The mixing amount of the metal-organic framework and the carbon-based catalyst material derived from MOF prepared by nitrogen-sintering the metal-organic framework was 0.1 to 100% by mass in 100% by mass of the air electrode catalyst material, Comparative Example, As the catalyst material as described in the examples, a mixture of this metal-organic framework and a carbon-based catalyst material derived from MOF prepared by nitrogen-sintering the metal-organic framework is used as PVDF or An air electrode can be created by combining with an aqueous emulsion of N-methylpyrrolidone or PTFE, CMC, or SBR.

Metal-organic frameworks (MOFs) have a porous coordination network structure with a high surface area due to the interaction of metal atoms and organic ligands. By supporting such a metal-organic framework on the surface of the air electrode catalyst material, electron insulation and ionic conductivity can be imparted, thereby suppressing the decomposition reaction on the air electrode catalyst material. It is presumed that it can be done.

The MOF is not particularly limited, but is a structure in which a metal atom (which may be a metal ion) and an organic ligand having two or more coordinating functional groups are continuously bonded. .. The MOF is typically a porous body having a plurality of pores inside. The MOF may include some functional molecule in the pores.

Examples of the metal atom constituting the MOF include, but are not limited to, iron, zinc, cobalt, niobium, zirconium, cadmium, copper, nickel, chromium, vanadium, titanium, molybdenum, zirconium and aluminum. The number of metal atoms constituting the MOF may be one or more. As the metal raw material of MOF, ^{a complex having metal ions such as Fe 2+} / Fe ³⁺ , Zn ²⁺ , Cu ²⁺ , Ni ²⁺ , and Co ²⁺ , and a metal-containing secondary structural unit (SBU) are particularly suitable.

The coordinating functional group of the organic ligand is a functional group capable of coordinating with a metal atom, such as a carboxyl group, an imidazole group, a hydroxyl group, a sulfonic acid group, a pyridine group, a tertiary amine group, an amide group, and a thioamide group. Can be mentioned. As the organic ligand, typically, one in which two or more coordinating functional groups are replaced with a skeleton having a rigid structure (for example, an aromatic ring, an unsaturated bond, etc.) is used. For example, 1,3,5-tris (4-carboxyphenyl) benzene (BTB), 1,4-benzenedicarboxylic acid (BDC), 2,5-dihydroxy-1,4-benzenedicarboxylic acid (DOBDC), cyclobutyl- 1,4-benzenedicarboxylic acid (CB BDC), 2-amino-1,4-benzenedicarboxylic acid (H2N BDC), tetrahydropyrene-2,7-dicarboxylic acid (HPDC), terphenyldicarboxylic acid (TPDC), 2 , 6-naphthalenedicarboxylic acid (2,6-NDC), pyrene-2,7-dicarboxylic acid (PDC), biphenyldicarboxylic acid (BPDC), any dicarboxylic acid with a phenyl compound, 3,3', 5,5 Examples thereof include'-biphenyltetracarboxylic acid, imidazole, benzimidazole, 2-nitroimidazole, cyclobenzimidazole, imidazole-2-carboxyaldehyde, 4-cyanoimidazole, 6-methylbenzimidazole, 6-bromobenzimidazole and the like.

Specific examples of the obtained MOF include, for example, _{MOF-177 represented by Zn 4} O (1,3,5-benzenetribenzoate) _{2 ; Zn 4} O (1,4-) also known as IRMOF-I. Benzene dicarboxylate) MOF-5 represented by _{3 ; MOF-74 (Mg) represented by Mg 2} (2,5-dihydroxy-1,4-benzenedicarboxylate); Zn ₂ (2,5-) MOF-74 (Zn) represented by dihydroxy-1,4-benzenedicarboxylate); _{MOF-505 represented by Cu 2} (3,3', 5,5'-biphenyltetracarboxylate); Zn ₄ IRMOF-6 represented by O (cyclobutyl-1,4-benzenedicarboxylate); _{IRMOF-3 represented by Zn 4} O (2-amino-1,4-benzenedicarboxylate) 3; Zn ₄ O ( _{Terphenyldicarboxylate) 3} or Zn ₄ O (tetrahydropyrene-2,7-dicarboxylate) ₃ represented by IRMOF-11; Zn ₄ O (tetrahydropyrene-2,7-dicarboxylate) ₃ IRMOF-8 represented; ZIF-68 represented by Zn (benzimidazolate) (2-nitroimidazolate); ZIF-69 represented by Zn (cyclobenzimidazolate) (2-nitroimidazolate); ZIF-7 represented by Zn (benz imidazolate) ₂ ; ZIF-9 represented by _{Co (benz imidazolate) 2 ; ZIF-11 represented by Zn 2} (benz imidazolate); Zn (imidazolate-) 2-Carboxaldehyde) _{ZIF-90 represented by 2} ; Zn (4-cyanoimidazolate) (2-nitroimidazolate) and ZIF-82; Zn (imidazolate) (2-nitroimidazolate). ZIF-70; ZIF-79 represented by Zn (6-methylbenzimidazolate) (2-nitroimidazolate); and ZIF represented by Zn (6-bromobenzimidazolate) (2-nitroimidazolate). -81 and the like can be mentioned. If the desired MOF is commercially available, a commercially available product may be used.

Further, in the present invention, the MOF itself described above can be used, but the MOF is heat-treated in nitrogen or the like to maintain its porosity as much as possible (for example, a carbon-based framework derived from a metal-organic framework (MOF)). It can also be applied as a material (as an oxide-based material derived from a metal-organic framework (MOF)), a catalyst as an air electrode of an air battery, or an electrode of a lithium ion battery or the like. Examples of the carbon-based material derived from the metal-organic framework (MOF) include a carbon-based material containing iron derived from MIL 100 (Fe). Examples of the oxide-based material derived from the metal-organic framework (MOF) include iron oxide-based materials such as _{Fe 2} O _{3 containing iron derived from MIL 100 (Fe).}

The MOF can be synthesized by a known method, but the method for synthesizing the MOF used in the present invention is not particularly limited. Typical methods for synthesizing MOF are a solution method and a hydrothermal method, and in addition, there are a solid phase synthesis method (mechanochemical method), a microwave method, an ultrasonic method and the like.

For example, noble metal-based nanocolloids, carbon quantum dots, graphene quantum dots, metal organic structures (MOF), using at least one selected from the group consisting of non-oxide ceramics, carbon-based materials, and composite oxides as a carrier. The air electrode catalyst material in the present invention is supported by supporting at least one selected from the group consisting of a carbon-based material derived from a metal organic structure (MOF) and an oxide-based material derived from a metal organic structure (MOF). Can be manufactured. Specifically, it can be produced by mixing 0.1-10% by mass with an air electrode material and mixing it with an aqueous emulsion of PVDF and N-methylpyrrolidone or PTFE, or with CMC or SBR. The noble metal-based nanocolloid can be produced by the same method as described above or by an impregnation method.

The catalyst layer may further contain a conductive material in order to further improve the conductivity. The conductive material may be any material that can impart conductivity to the air electrode catalyst material or improve the conductivity of the air electrode catalyst material, for example, carbon black such as Ketjen black and acetylene black, and carbon such as carbon nanotubes. Examples thereof include quality materials, conductive polymers such as polythiazyl and polyacetylene. Among them, when used as an electrode material for an air metal battery, a carbonaceous material is preferable from the viewpoint of having mesopores on the surface and storing discharge precipitates, and in particular, Ketjen black, carbon nanotubes and the like are preferable. The conductive material may also function as a carrier for the carbon alloy.

The content ratio of the conductive material is not particularly limited, but from the viewpoint of ensuring conductivity, it is preferably less than 60% by mass when the mass of the entire catalyst layer is 100% by mass. More preferably, it is ~ 50% by mass.

The catalyst layer may further contain a binder to immobilize the air electrode catalyst material. The binder may contain a support that is not intended to collect current. Examples of the binder include olefin resins such as polyethylene and polypropylene, fluororesins such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), polyamide resins, and rubbers such as styrene-butadiene rubber (SBR rubber). Examples include system resins.

The content ratio of the binder is not particularly limited, but is preferably less than 60% by mass when the mass of the entire catalyst layer is 100% by mass from the viewpoint of ensuring conductivity. More preferably, it is ~ 50% by mass.

A solvent can be used to form a paste containing an air electrode catalyst material, a conductive material, a binder and the like. The solvent is not particularly limited as long as it has volatile properties, and can be appropriately selected. Specific examples thereof include acetone, N, N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP) and the like. A solvent having a boiling point of 200 ° C. or lower is preferable because the air electrode mixture paste can be easily dried.

The content ratio of the solvent is not particularly limited, but from the viewpoint of ease of application, it is preferably less than 60% by mass when the mass of the entire catalyst layer is 100% by mass, and 5 to 5 More preferably, it is 50% by mass.

The air electrode catalyst material: conductive material: binder: solvent mixture ratio (mass ratio) may be 40 to 60: 5 to 15: 5 to 15: 20 to 40 from the viewpoint of ease of coating. preferable.

The thickness of the catalyst layer varies depending on the application of the metal-air battery and the like, but is preferably in the range of, for example, 2 μm to 500 μm, particularly preferably in the range of 5 μm to 300 μm.

The air electrode may be provided with a positive electrode current collector that collects electricity from the air electrode, if necessary. The positive electrode current collector contains at least one selected from the group consisting of titanium metal, molybdenum metal, nickel alloy, tungsten metal, zirconium metal, tantalum metal and carbon metal. The positive electrode current collector can be used without particular limitation, such as a porous structure (specific example, mesh shape, etc.), a mesh structure, a fiber, a non-woven fabric, a foil shape, a plate shape, etc., but has high oxygen supply performance. Moreover, from the viewpoint of excellent current collection efficiency, a porous structure is preferable.

For example, as the titanium metal, molybdenum metal, tungsten metal, zirconium metal, and tantalum metal, a commercially available mesh-like material (for example, the material as described above) can be used as it is.

For example, as the nickel-based alloy, those based on nickel with iron, chromium, niobium, molybdenum, tin, tungsten and the like added are preferable, and specifically, Inconel 600, Inconel 625, Inconel 718, Inconel X750 and the like are used. Can be mentioned.

For example, as carbon-based materials, carbon fiber (carbon fiber) and activated carbon are used from the viewpoints of excellent corrosion resistance, excellent electron conductivity, and lighter weight than metal, resulting in higher energy density per weight. (Carbon plate activated) and the like can be mentioned, and carbon fiber is particularly preferable because of its high electron conductivity. Examples of the type of carbon fiber include PAN-based carbon fiber and pitch-based carbon fiber.

Examples of the air electrode current collector using carbon fiber include carbon cloth, carbon paper, and carbon felt. Carbon cloth generally refers to carbon fibers woven regularly (corresponding to the above mesh structure). On the other hand, the carbon paper generally refers to a material in which carbon fibers are randomly arranged (corresponding to the above-mentioned non-woven fabric structure). The carbon paper usually refers to carbon fibers mixed with a binder formed in the manner of papermaking. Further, carbon felt may be used as the air electrode current collector using carbon fiber. Carbon felt usually refers to a random arrangement of carbon fibers (corresponding to the above-mentioned non-woven fabric structure). The carbon felt is usually formed by entwining carbon fibers with water and randomly arranging them.

Carbon cloth, carbon paper and carbon felt are manufactured by completely different methods. Further, in the present invention, carbon cloth, carbon paper and carbon felt may be used in layers. This is because an air electrode current collector with improved mechanical strength can be obtained.

The positive electrode current collector preferably has a porous structure, and above all, a porous structure such as carbon paper or a metal mesh made of a corrosion-resistant material is preferable. From the viewpoint of corrosion resistance, carbon paper is more preferable. As the metal mesh made of a corrosion-resistant material, for example, a metal mesh formed of titanium metal, molybdenum metal, nickel-based alloy, or the like can be used. As another positive electrode current collector, a metal foil having an oxygen supply hole can also be used. The battery case may also have the function of a positive electrode current collector.

The thickness of the positive electrode current collector varies depending on the application of the metal-air battery and the like, but is preferably in the range of, for example, 10 μm to 1000 μm, particularly preferably in the range of 20 μm to 400 μm.

The catalyst layer may contain a positive electrode current collector therein. The positive electrode current collector may be located in the center of the catalyst layer or may be present in layers on one side of the catalyst layer. When the positive electrode current collector is present on one side of the catalyst layer, the positive electrode current collector can usually be located on the side of contact with air on the opposite side of the electrolyte. The shape of the catalyst layer includes not only a layered shape but also other shapes (for example, pellet shape, plate shape, mesh shape, etc.).

The method for producing the air electrode is not particularly limited, and a well-known method can be used. For example, by applying at least the air electrode catalyst material of the present invention and, if necessary, an air electrode mixture paste mixed with a conductive material, a binder, a solvent, etc., to the surface of the positive electrode current collector and drying it. , An air electrode in which a catalyst layer and a positive electrode current collector are laminated can be produced. Alternatively, the catalyst layer obtained by applying and drying the above-mentioned air electrode mixture paste is superposed on the positive electrode current collector, and appropriately pressurized or heated to form the catalyst layer and the positive electrode current collector. It is also possible to produce laminated air electrodes. The method of applying the air electrode mixture paste is not particularly limited, and a general method such as a doctor blade or a spray method can be used.

The thickness of the air electrode varies depending on the application of the metal-air battery, etc., but when the material is foil-shaped, plate-shaped, etc., it is, for example, in the range of 2 μm to 10 mm, particularly in the range of 5 μm to 2 mm. Is preferable.

<Electrolyte>
The electrolyte in the present invention is held between the negative electrode and the air electrode. The electrolyte in the present invention has a function of exchanging metal ions between the negative electrode and the air electrode. The electrolyte in the present invention preferably contains an ionic liquid or a deep eutectic solvent. From the viewpoint of suppressing the generation of by-products, the electrolyte in the present invention preferably contains an ionic liquid.

Here, the "ionic liquid" is a compound composed of a combination of anions and cations, and means a salt that exists as a liquid even at room temperature. Many ionic liquids can be considered depending on the combination of anions and cations. Examples of the cation include those derived from aromatic amines such as imidazolium (for example, dialkylimidazolium) and pyridinium (for example, alkylpyridinium), ammonium (for example, tetraalkylammonium), and pyrrolidinium (for example, cyclic). (Pyridinium, etc.) and other aliphatic amine-derived substances can be mentioned. Examples of the anion include halogen ions such as ^{Cl −} , Br ⁻ , and I ⁻ , and fluoride ions such as _{BF 4} ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ⁻ , and (CF ₃ SO ₂ ) ₂ N ^−. Be done. Recently, imidazolium salts composed of nitric acid and acetic acid may become ionic liquids, general-purpose anions such as alkyl sulfonic acids, and polyvalent anions such as sulfuric acid and phosphoric acid may also form ionic liquids. That is, there are also non-halogen ionic liquids in this way. In addition, naturally occurring ions such as amino acids, sugars, sugar derivatives, and lactic acid are increasingly forming ionic liquids. In addition, there are ionic liquids having S (sulfur) -containing ions and carboxylic acid ions as anions, and ionic liquids having phosphonium and sulfonium as cations.

Further, if a hydrophobic ionic liquid having a melting point of several tens of degrees or less is used, it is possible to suppress the deterioration of the characteristics of the air battery caused by the volatilization of the electrolyte. Further, since the ionic liquid may change due to residual moisture or the like, it is preferable to dry the ionic liquid before use. As the drying method, a known drying method can be adopted.

From the viewpoint of suppressing the generation of by-products, high ionic conductivity, low volatility, high thermal stability, etc., the cations of the ionic liquid are imidazolium, pyridinium, ammonium, pyrrolidinium, pyrazolium, piperidinium, morpholinium, sulfonium, and It is at least one selected from the group consisting of phosphonium, and the anions of the ionic liquid are halogen ions, amide ions, imide ions, fluoride ions, sulfate ions, phosphate ions, fluorosulfate ions, lactic acid ions, and carboxylic acids. It is preferably at least one selected from the group consisting of ions. The cations and anions as described above can be freely combined. As the cation and the anion, only one kind may be used alone, or two or more kinds may be combined.

Typical cations include imidazolium, pyridinium, ammonium, pyrrolidinium, pyrizolium, piperidinium, morpholinium, sulfonium, phosphonium and the like from the viewpoint of suppressing by-products.

Specifically, examples of the imidazolium include dialkyl imidazoliums such as 1-ethyl-3-methylimidazolium (EMIm) and 1-butyl-3-methylimidazolium (BMIm), 1-ethyl-2,3. −Dimethylimidazolium, 1-allyl-3-methylimidazolium, 1-allyl-3-ethylimidazolium (AEIm), 1-allyl-3-butylimidazolium, 1,3-diallylimidazolium (AAIm), etc. Can be mentioned.

Examples of the pyridinium include alkylpyridinium such as 1-propylpyridinium and 1-butylpyridinium, 1-ethyl-3- (hydroxymethyl) pyridinium, 1-ethyl-3-methylpyridinium and the like.

Examples of the ammonium include N, N, N-trimethyl-N-propylammonium (TMPA), N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium (DEME), and methyltrioctylammonium. Etc., such as tetraalkylammonium.

Examples of the pyrrolidinium include N-methyl-N-propylpyrrolidinium (P13), N-methyl-N-butylpyrrolidinium (P14), N-methyl-N-methoxymethylpyrrolidinium and the like. ..

Examples of the pyrazolium include 1-ethyl-2,3,5-trimethylpyrazolium, 1-propyl-2,3,5-trimethylpyrazolium, 1-butyl-2,3,5-trimethylpyrazolium. Rium and the like can be mentioned.

Examples of the piperidinium include N-methyl-N-propyl piperidinium (PP13), N, N, N-trimethyl-N-propylammonium and the like.

Examples of the morpholinium include N, N-dimethylmorpholinium, N-ethyl-N-methylmorpholinium, N, N-diethylmorpholinium and the like.

Examples of the sulfonium include trimethylsulfonium, tributylsulfonium, and triethylsulfonium.

Examples of the phosphonium include tributylhexadecylphosphonium, tributylmethylphosphonium, tributyl-n-octylphosphonium, tetrabutylphosphonium, tetra-n-octylphosphonium, tetrabutylphosphonium, tributyl (2methoxyethyl) phosphonium and the like.

Examples of anions that form an ionic liquid in combination with the above cations include halogen ions, amide ions, imide ions, fluoride ions, sulfate ions, phosphate ions, fluorosulfate ions, and lactic acid from the viewpoint of suppressing by-products. Ions, carboxylic acid ions and the like can be mentioned.

Specifically, examples of the halogen ion include Cl ⁻ , Br ⁻ , I ^{− and the} like. Halogen ions, halogen oxoacid ion _{^{(YO 4 -, YO 3 -}} , YO 2 -, or YO ^-; Y represents Cl, Br, or I), AlX ₄ ^- (X is Cl, Br or I Yes, each X is the same or different, that is, AlX ₄ ⁻ is, for example, AlCl ₄ ⁻ , AlBr ₄ ⁻ , AlI ₄ ⁻ , AlClBr ₃ ⁻ , AlClI ₃ ⁻ , AlCl ₂ BrI ⁻ , AlClBr ₂ I ⁻ , AlClBrI. ₂ ⁻ etc.) and other halogen-containing compounds are also included.

Examples of the amide ion, for example, bis (trifluoromethanesulfonyl) amide ion _{(N (SO 2 CF 3)} 2 -), bis (fluorosulfonyl) amide ion, and the like.

Examples of the imide ion include bistrifluoromethylsulphonylimide ion (TFSI ⁻ ), (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , (C ₃ F ₇ SO ₂ ) ₂ N. _{^{-, (CF 3 SO 2)}} (C 2 F 5 SO 2) N -, (CF 3 SO 2) (C 3 F 7 SO 2) N -, (C 2 F 5 SO 2) (C 3 F 7 SO ₂ ) N ⁻ , N (C ₄ F ₉ SO ₂ ) ₂ ^{− and the} like can be mentioned.

Examples fluoride ion, for example, tetrafluoroborate ion (BF ₄ ^-), hexafluorophosphate ion ^{_{(PF 6 -), SbF 6}} - , and the like.

Examples of the sulfate ion, for example, HSO ₄ ^-, methosulfate ^{_{(CH 3 OSO 3 -),}} CH 3 SO 3 -, C 4 H 9 OSO 3 -, CH 3 C 6 H 4 SO 3 -, C 8 H ₁₆ SO ₃ ⁻ , C ₂ H ₅ OSO ₃ ⁻ , C ₆ H ₁₃ OSO ₃ ⁻ , C ₈ H ₁₇ OSO ₃ ⁻ , C ₄ F ₉ SO ₃ ^{− and the} like.

Examples of the phosphate ion include fluorophosphate ions such as hexafluorophosphate ion (PF ₆ ⁻ ) and (C ₂ F ₅ ) ₃ PF ₃ ⁻ , hypophosphite ion (H ₂ PO ₂ ⁻ ), and the like. Examples thereof include (C ₂ F ₅ ) ₃ PF ₃ ⁻ , (CH ₃ ) ₂ PO ₄ ⁻ , (C ₂ H ₅ ) ₂ PO ₄ ⁻ , and (CH ₅ ) _{2 PO 4} ^−.

Examples of the fluorosulfate ion include (CF ₃ SO ₂ ) ₂ N ⁻ , CF ₃ SO ₃ ^{− and the} like.

Examples of the lactic acid ion include C ₂ O ₃ H ^{− and the} like.

Examples of the carboxylic acid ion include acetate ion (CH ₃ COO ⁻ ), CH ₃ OCO ₂ ⁻ , C ₉ H ₁₉ CO ₂ ^{− and the} like.

Besides, thiocyanate ion (SCN ^-), nitrate ion (NO ₃ ^-), bicarbonate ions (HCO ₃ ^-), trifluoromethanesulfonate ion, dicyanamide _{ion, B (C 6 H 5)} 4 -, tetra phenylboronic acid ion _{^{(BPh 4 -), B (}} C 2 O 4) 2 -, (CN) 2 N -, C 4 BO 8 - , and the like.

The ionic liquid can be formed by freely combining the above-mentioned cations and anions. As the cation and the anion, only one kind may be used alone, or two or more kinds may be combined. As the anions that form an ionic liquid in combination with the above cations, Cl ⁻ , Br ⁻ and I ⁻ are preferable from the viewpoint of reversibility of the positive electrode reaction and storage performance. Specific examples of the ionic liquid include dialkylimidazolium halides, ethyltributylphosphonium halides, tetraalkylammonium halides and the like, and dialkylimidazolium halides include 1-ethyl-3-methylimidazolium chloride ([EMIM]. ] ・ Cl), 1-ethyl-3-methylimidazolium bromide ([EMIM] ・ Br), 1-ethyl-3-methylimidazolium iodide ([EMIM] ・ I), 1-butyl-3-methylimidazole 1, A 3-dialkylimidazolium halide can be preferably used.

As the ethyltributylphosphonium halide, ethyltributylphosphonium chloride ([EBP] · Cl), ethyltributylphosphonium bromide ([EBP] · Br), ethyltributylphosphonium iodide ([EBP] · I) and the like are suitable. Can be used for.

The tetraalkylammonium halides, tetraethylammonium bromide _{([E 4 N] · Br} ), trimethylethylammonium chloride _{([M 3 EN] · Cl} ), tetrabutylammonium chloride _{([Bu 4 N] · Cl} ) , etc. It can be preferably used.

The electrolyte in the present invention can usually have a metal salt in addition to the ionic liquid and the non-aqueous solvent described later. As such a metal salt, any one containing a metal ion conducting between the negative electrode and the air electrode can be used without particular limitation. For example, an aluminum salt and the like can be mentioned, and examples of the aluminum salt include an inorganic aluminum salt such as an aluminum halide such as _{AlCl 3 and aluminum bromide, and an organic aluminum salt.} When a metal salt is contained, 40 to 80% by weight is preferable, and 50 to 70% by weight is more preferable in the electrolyte.

From the viewpoint of providing a highly practical metal air battery, the combination of the ionic liquid and the metal salt is preferably a combination of a dialkylimidazolium halide and an aluminum halide, for example, 1-ethyl-3-methylimidazolium bromide. And AlBr ₃ can be combined, or 1-ethyl-3-methylimidazolium chloride and AlCl ₃ can be combined.

The reaction when 1-ethyl-3-methylimidazolium chloride ([EMIM] · Cl) and AlCl ₃ are used is described below as an example. The following reaction forms an ionic liquid with an ion pair.
_{^{(1) [EMIM] + Cl}} - = + AlCl 3 [EMIM] + [AlCl 4] -
(2) [EMIM] ⁺ [AlCl ₄ ] ^- + AlCl ₃ = [EMIM] ⁺ [Al ₂ Cl ₇ ] ^-
(3) [EMIM] ⁺ [Al ₂ Cl ₇ ] ⁻ + AlCl ₃ = [Al ₃ Cl ₁₀ ] ⁻
Two types of precipitation forms are conceivable depending on the mol ratio of [AlCl _{3] and "EMIM".} First, when [AlCl ₃ ] is 50 mol% or less, it is considered that it exists as ^{Cl −} and [AlCl ₄ ] ^−. The second is considered to be present when [AlCl ₃ ] is more than 50 mol% (excess), such as [AlCl ₄ ] ⁻ and [Al ₂ Cl ₇ ] ⁻ . In this way, when an aluminum salt and an organic compound such as a dialkylimidazolium salt are mixed, they form an ion pair to obtain a melt (ionic liquid). Since the metal ions generated from the negative electrode during discharge (for example, aluminum ions when the negative electrode is aluminum) are more stable with the ionic liquid than the hydroxide ions, it is considered that the generation of by-products can be suppressed. .. ^{_{Also, [Al 2 Cl 7] -}} [Al 3 Cl 10] - When the anion multimers are present as, for aluminum ions is considered likely to be reduced to Al, the generation of by-products It can be suppressed, and when aluminum is used as the negative electrode, it is also useful as a negative electrode.

The electrolyte in the present invention preferably contains a deep eutectic solvent from the viewpoint of safety, cost and the like. Here, the "deep eutectic solvent" is generally formed by a mixture of a hydrogen bond donor compound and a hydrogen bond acceptor compound, and has a melting point due to eutectic. Means a large drop. The deep eutectic solvent is a medium whose cost is dramatically lower than that of an ionic liquid (it is considered that the cost is 2 to 3 orders of magnitude lower than that of an ionic liquid) while maintaining low volatility and resistance to ignition. .. A large number of deep eutectic solvents can be considered depending on the combination of the hydrogen bond donor compound and the hydrogen bond acceptor compound.

The deep eutectic solvent may be a mixture of a hydrogen bond donor compound and a hydrogen bond acceptor compound whose melting point is greatly lowered by eutectic, and is not particularly limited. be able to. For example, a mixture of a hydrogen bond acceptor compound that is solid at room temperature (25 ° C) and a hydrogen bond donor compound that is solid or liquid at room temperature (25 ° C), and is liquid at room temperature (25 ° C). A eutectic solvent is preferred.

Examples of the hydrogen bond acceptor compound constituting the deep eutectic solvent include salts and the like. As the salt, a halogen salt or the like can be used. For example, examples of the halogen salt include metal halides and non-metal halides, but from the viewpoint of practicality, metal halides are preferable.

For example, the metal halide can be used without particular limitation as long as it forms a deep eutectic solvent by mixing with the hydrogen bond donor compound. For example, examples of the metal halide include aluminum halides (for example, aluminum iodide, aluminum bromide, aluminum chloride, aluminum fluoride, etc.), and aluminum halides are preferable from the viewpoint of being used in an aluminum air cell. As the aluminum halide, it is preferable to use aluminum chloride from the viewpoint of production cost. Further, metal chloride, metal chloride hydrate and the like can also be used. The metal halide (for example, aluminum halide) may be used alone or in combination of two or more. As the metal halide, a metal halide hydrate can be used. When the metal halide is contained, 40 to 80% by mass is preferable, and 50 to 70% by mass is more preferable in the electrolyte. Other examples of the metal halogen salt include zinc chloride and the like.

The non-metal halogen salt is not particularly limited, and examples thereof include a quaternary ammonium salt, a quaternary phosphonium salt, a tertiary ammonium salt, and a primary ammonium salt.

The quaternary ammonium salt is not particularly limited, and is, for example, choline chloride, tetrabutylammonium chloride, tetramethylammonium chloride, methyltrioctylammonium chloride, tetraoctylammonium chloride, acetylcholine chloride, chlorocholine chloride, tetraethyl bromide. Examples thereof include ammonium, N- (2-hydroxyethyl) -N, N-dimethylbenzenemethaneaminium chloride, fluorocholine bromide, tetrabutylammonium bromide and the like.

Examples of the quaternary phosphonium salt include methyltriphenylphosphonium bromide, benzyltriphenylphosphonium chloride and the like. Examples of the tertiary ammonium halide include 2- (diethylamino) ethanol hydrochloride. Examples of the primary ammonium halide include ethylamine hydrochloride.

For example, the hydrogen bond donor compound can be used without particular limitation as long as it forms a deep eutectic solvent by mixing with the hydrogen bond acceptor compound. For example, as the hydrogen binding donor, ethylene glycol, glycerin, lactic acid, tartrate acid, glucose, sucrose, xylose, ascorbic acid, citric acid, urea, thiourea, 1-methylurea, 1,3-dimethylurea, 1, 1-dimethylurea, ethyleneurea, tetramethylurea, acetamide, dimethylacetamide, 2,2,2-trifluoroacetamide, benzamide, 4-propylpyridine, 2-hydroxypyridine, imidazole, adipic acid, benzoic acid, malonic acid, Shuic acid, phenylacetic acid, 3-phenylpropionic acid, succinic acid, 1,2,3-propanetricarboxylic acid, levulinic acid, itaconic acid, xylitol, D-sorbitol, D-isosorbide, 4-hydroxybenzoic acid, coffee acid, p-kumalic acid, trans-silicic acid, suberic acid, gallic acid, resorcinol, hexanediol, 1,4-butanediol, triethylene glycol; formic acid, acetic acid, butanoic acid, pentanoic acid, hexanic acid, heptanic acid, octane Acids, nonanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, eicosanoic acid, docosanoic acid, tetiracosanoic acid, hexacosanoic acid, octacosanoic acid, triaconic acid, etc. Can be mentioned.

Among the above-described hydrogen-bonded donor compounds, a nitrogen-containing hydrogen-bonded donor compound is preferable from the viewpoint of practicality. For example, examples of the nitrogen-containing hydrogen-bonded donor compound include urea compounds such as urea, thiourea, 1-methylurea, 1,3-dimethylurea, 1,1-dimethylurea, ethyleneurea, and tetramethylurea; Amide compounds such as aliphatic amides such as acetoamide and dimethylacetamide, cyclic amides such as benzamide (for example, aromatic, carbocyclic or heterocyclic amides); pyridine compounds such as 4-propylpyridine and 2-hydroxypyridine From the viewpoint of safety, it is preferable to use a urea compound, an amide compound, or a pyridine compound.

As for the combination of the hydrogen bond acceptor compound and the hydrogen bond donor compound, a large number of deep eutectic solvents can be considered depending on the combination. For example, a quaternary ammonium salt and a hydrogen bond donor compound such as amine or carboxylic acid can be considered. Examples thereof include a combination of the above-mentioned metal halide and a hydrogen-bonding donor compound containing nitrogen such as a urea compound, an amide compound or a pyridine compound. For example, a preferred combination of deep eutectic solvents may be a mixture of an aluminum halide (preferably aluminum chloride) and a nitrogen-containing hydrogen-bonded donor compound (preferably a urea compound, an amide compound, a pyridine compound). Examples include the deep eutectic solvent formed. Specifically, preferred combinations include, for example, aluminum chloride and urea, aluminum chloride and acetamide, aluminum chloride and 4-propylpyridine and the like.

The method for producing the deep eutectic solvent is not particularly limited, and a well-known method can be used. For example, when a deep eutectic solvent is produced using a hydrogen-bonded donor compound (eg, urea, acetamide, etc.) containing an aluminum halide (for example, aluminum chloride) and nitrogen, first, a hydrogen bond containing nitrogen is produced. The donor compound is dried under reduced pressure, if necessary, at about 100 to 130 ° C. for 24 hours or more. Then, the hydrogen-bonded donor compound containing aluminum halide and nitrogen is mixed in a predetermined molar ratio (for example, aluminum halide: hydrogen-bonded donor compound containing nitrogen = 1.0 to 2.0: 1.0). ), The aluminum halide is slowly added to the hydrogen-bonded donor compound containing nitrogen to prepare a mixture. Then, the deep eutectic solvent can be produced by heating the mixture at room temperature, if necessary, at about 100 to 150 ° C. for about 0.1 to 10 hours until a liquid reaction product is formed. For example, when a deep eutectic solvent is formed by mixing _{urea and AlCl 3} , heterolytic cleavage of _{AlCl 3} (Al ₂ Cl _{6 units) produces AlCl 4} ^- anion and [AlCl ₂ -urean] ⁺ cation. It is presumed that it will be obtained and will perform the same function as an ionic liquid.

In the present invention, the deep eutectic solvent is preferably a naturally derived deep eutectic solvent. Here, the "naturally-derived deep eutectic solvent" (Natural Deep Eutectic Solvent) means a deep eutectic solvent formed of a naturally-derived component among the deep eutectic solvents. As a naturally occurring component, for example, the hydrogen bond acceptor compound is composed of a quaternary ammonium salt such as choline chloride or an aluminum halide such as aluminum chloride, and has a hydrogen bond donor property. Examples of the compound include those composed of urea, ethylene glycol, glycerin, lactic acid, tartrate acid, glucose, sucrose, xylose, ascorbic acid, citric acid and the like, and specific combinations include aluminum halides and nitrogen. A combination of hydrogen-bonded donor compounds containing the above is preferred. The hydrogen-bonded donor compound containing an aluminum halide or nitrogen may be one kind or a plurality of two or more kinds. Specific preferred combinations include a combination of AlCl ₃ / urea / ethylene glycol and the like. The molar ratio of AlCl ₃ / urea / ethylene glycol is preferably 1.0: 1.0: 0.1 to 0.5.

When a deep eutectic solvent is used as the electrolyte, at least one selected from the group consisting of an ionic liquid and a non-aqueous electrolyte solution having a high boiling point is further contained from the viewpoint of preventing volatilization of the deep eutectic solvent. Is preferable. The content of the ionic liquid or the high boiling point non-aqueous electrolyte solution contained in the electrolyte is preferably 0.1 to 30% by mass, more preferably 0.5 to 20% by mass, and 1 to 1 to 20% by mass, from the viewpoint of preventing volatilization. 10% by mass is more preferable. The mass ratio of the deep eutectic solvent to the ionic liquid or the non-aqueous electrolyte solution having a high boiling point is as follows: Deep eutectic solvent: ionic liquid or non-aqueous electrolyte solution having a high boiling point = 1: 0.01 to It is preferably 0.3. When both an ionic liquid and a non-aqueous electrolytic solution having a high boiling point are included, it is preferable to adjust the combined value so as to be included in the above range. From the same viewpoint, when an ionic liquid is used as the electrolyte, it can further contain at least one selected from the group consisting of a deep eutectic solvent and a non-aqueous electrolyte solution having a high boiling point. The content and the like are the same as when the above-mentioned deep eutectic solvent is used.

The electrolyte in the present invention may contain a non-aqueous electrolyte solution from the viewpoint of preventing volatilization of the solvent. The non-aqueous electrolyte solution is not particularly limited as long as it can prevent the volatilization of the solvent, and known ones can be used, but esters, carbonic acid esters, ethers, nitriles, and each of the above compounds (esters). , Carbonated esters, ethers, nitriles), and it is desirable to contain at least one selected from the group consisting of compounds in which a substituent is introduced. Preferred are those selected from esters and carbonic acid esters. Among the esters, esters having a cyclic structure are preferable, and γ-butyrolactone (γBL) having a 5-membered ring is particularly preferable.

As the carbonic acid esters, both cyclic and chain structures can be used. Cyclic carbonate esters are preferably carbonate esters having a 5-membered ring structure, and in particular, ethylene carbonate (EC), propylene carbonate (PC), vinylene carbonate (VC), butylene carbonate, γ-butyl lactone, dimethyl carbonate (DMC), and the like. Ethyl methyl carbonate (EMC), diethyl carbonate (DEC) and the like are preferable. From the viewpoint of viscosity adjustment, it can also be used together with an ionic liquid. As the chain carbonic acid esters, carbonic acid esters having 7 or less carbon atoms are preferable, and dimethyl carbonate (DMC), diethyl carbonate (DEC), and ethyl methyl carbonate (EMC) are particularly preferable.

As the ethers, either a cyclic structure or a chain structure can be used. As the cyclic ethers, ethers having a 5-membered ring and a 6-membered ring structure are preferable, and among them, those containing no double bond are preferable. The chain ethers preferably contain 5 or more carbon atoms. For example, tetrahydropyran, dioxane, tetrahydrofuran, 2-methyltetrahydrofuran, butyl ether, isopentyl ether, 1,2-dimethoxyethane, methyl acetate, 2-methyltetrahydrofuran 1,3-dioxolane, 4-methyl-1,3-dioxolane, Examples thereof include diethyl ether, 3-methyloxazolidinone, methylsulfolane formate, dimethylsulfonide and the like.

Examples of nitriles include acetonitrile, propionitrile and the like.

In the present invention, from the viewpoint of preventing volatilization of the electrolyte, it is preferable to use a non-aqueous electrolyte solution having a high boiling point among the non-aqueous electrolyte solutions. For example, as the non-aqueous electrolytic solution having a high boiling point, a non-aqueous electrolytic solution having a boiling point of 160 ° C. or higher is preferable, and if cyclic carbonates such as ethylene carbonate (EC) and propylene carbonate (PC) are used, these are high. It is preferable because it has a boiling point.

The non-aqueous electrolytic solution may be used alone, but it is preferable to use a mixture of a plurality of types. In particular, it is preferable to contain carbonic acid esters, and in particular, it is preferable to contain carbonic acid esters having a 5-membered ring structure, and it is particularly preferable to contain EC or PC.

The preferred composition of the non-aqueous electrolyte solution is EC / PC, EC / γBL, EC / EMC, EC / PC / EMC, EC / EMC / DEC, EC / PC / γBL.

In the present invention, the electrolyte is preferably in a solid state from the viewpoint of preventing liquid leakage. Examples of the solid electrolyte include gelled liquid electrolytes, solidified liquid electrolytes, and solid electrolytes.

For example, as a method of gelling a liquid electrolyte, there is a method of adding the following polymer to the electrolyte in the present invention to gel. Examples of such a polymer include cellulosic polymers such as polyethylene oxide (PEO), polyacrylic nitrile (PAN), polymethyl methacrylate (PMMA), and carboxymethyl cellulose, and polymers such as polyvinylidene fluoride (PVDF). When the liquid electrolyte is gelled and used, for example, a solid electrolyte can be produced by mixing the above-mentioned polymer and the liquid electrolyte, applying the mixture onto a metal negative electrode, and drying the mixture. can. The mass ratio of the polymer added to the electrolyte is preferably electrolyte: polymer = 1: 0.01 to 0.3 from the viewpoint of preventing liquid leakage.

For example, as a method for solidifying a liquid electrolyte, there is a method of impregnating the following inorganic particles with the electrolyte in the present invention to solidify the liquid electrolyte. Examples of such inorganic particles include glass, crystals, glass ceramics, and the like, and specific examples thereof include SiO ₂ , TiO ₂ , ZnO, Al ₂ O ₃ , BaTiO ₃ particles, and the like. When the liquid electrolyte is solidified and used, for example, a solid electrolyte can be produced by applying a slurry in which _{SiO 2 particles and the liquid electrolyte are mixed as described above and drying the slurry.} The mass ratio of the inorganic particles added to the electrolyte is preferably electrolyte: inorganic particles = 1: 0.2 to 4.0 from the viewpoint of preventing liquid leakage.

In the present invention, from the viewpoint of preventing volatilization, the electrolyte preferably further contains a moisturizer. The moisturizer is not particularly limited as long as it can prevent the solvent from volatilizing, and known moisturizers can be used. For example, either hydrophilic or hydrophobic can be used without particular limitation according to the solvent of the electrolyte. For example, hydrophobic moisturizers include flaxseed oil, corn oil, olive oil, sunflower oil, rapeseed oil, sesame oil, soybean oil, cacao oil, palm oil, palm oil, mokuro and other natural oils, paraffin, vaseline, selecin, and fluid. There are paraffin, squalane, wax, higher fatty acid, silicone oil, crosslinked silicone oil and the like, and they can be used alone or in combination of two or more kinds. For example, examples of the hydrophilic moisturizer include glycerins such as glycerin, diglycerin, and triglycerin. Further, the above-mentioned ionic liquid or non-aqueous electrolyte having a high boiling point can also be used as a moisturizer. The content of the moisturizer contained in the electrolyte is preferably 0.01 to 30% by mass, more preferably 0.1 to 15% by mass, from the viewpoint of preventing volatilization. The mass ratio of the solvent to the moisturizer is preferably solvent: moisturizer = 1: 0.01 to 0.2 from the viewpoint of preventing volatilization.

The electrolyte in the present invention may further include a separator. The separator can be arranged to ensure the insulating property between the air electrode and the negative electrode. By impregnating the separator with an electrolyte, the insulating property between the air electrode and the negative electrode and the metal ion conductivity can be ensured. The separator is not particularly limited, and for example, a polymer non-woven fabric such as a polypropylene non-woven fabric or a polyphenylene sulfide non-woven fabric, a microporous film such as an olefin resin such as polyethylene or polypropylene, a woven fabric thereof, or a combination thereof may be used. Can be done. Further, as the separator, various filter sheets such as a liquid filter, various medical / protective material sheets such as towels, gauze, and tissues can also be used. You can also stack several sheets.

The thickness of the separator is preferably 0.01 mm to 5 mm, more preferably 0.05 mm to 1 mm, from the viewpoint of ensuring insulation and reducing the thickness of the battery.

<Metal-air battery>
The metal-air battery of the present invention can usually have a battery case that houses an air electrode, a negative electrode, and an electrolyte. The shape of the battery case is not particularly limited, but specifically, it can take a desired shape applied to the primary battery and the secondary battery such as a coin type, a flat plate type, a cylindrical type, and a laminated type. The battery case may be an open type to the atmosphere or a closed type. The open-air battery case has a structure in which at least the air electrode can sufficiently contact the atmosphere. On the other hand, the sealed battery case can be provided with an oxygen (air) introduction pipe and an exhaust pipe, which are positive electrode active materials. In this case, the gas to be introduced into the battery case preferably has a high oxygen concentration, and more preferably pure oxygen. Further, the battery case may be provided with a structure such as an injection hole for replenishing the electrolytic solution or the like.

The method for manufacturing the metal-air battery of the present invention will be described. The method for producing the metal-air battery of the present invention is not particularly limited, and a well-known method can be used. For example, in the case of manufacturing a coin cell type metal-air battery, in an inert gas atmosphere, the negative electrode is first placed in the battery case, then the separator is placed on the negative electrode, and then from above the separator. , The electrolyte is injected, then the air electrode with the catalyst layer and the positive electrode current collector is placed with the catalyst layer facing the separator side, then placed in the air electrode side battery case, and these are finally placed. The method of caulking can be mentioned, but the method is not limited to this.

The metal-air battery of the present invention can be used for a primary battery or a secondary battery. The metal-air battery of the present invention can be applied to a device that can use a normal primary battery or a secondary battery. For example, mobile phones, mobile devices, robots, personal computers, in-vehicle devices, various home electric appliances, stationary power supplies, and the like can be mentioned. In addition, it can be used not only as a backup power source for memory of personal computers and mobile terminals, as a power source for measures against instantaneous power outages such as personal computers, but also as an electric vehicle or hybrid vehicle, a solar power generation energy storage system used in combination with a solar cell, and the like. It can be suitably used for various purposes in the industrial field of.

The metal-air battery of the present invention is classified as an aluminum-air battery and has a theoretical capacity of 8100 Wh / kg. The metal-air battery of the present invention can be a metal-air battery using a deep eutectic solvent-based electrolyte from the viewpoint of safety, cost, and the like. For example, aluminum air using a deep eutectic solvent-based electrolyte. It can be a battery. Further, the metal-air battery of the present invention can be an all-solid-state metal-air battery in which the electrolyte is in a solid state from the viewpoint of preventing liquid leakage of the electrolyte and ensuring long-term stability. For example, all-solid-state aluminum air. It can be a battery.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. The evaluation items in the examples and the like were measured as follows.

(1) Charge / discharge characteristics and battery capacity The charge / discharge characteristics of each metal-air battery obtained as described below were performed under the following conditions. The charging / discharging was started, and the charging / discharging was performed in an environment of 25 ° C. The battery capacities and voltages measured after 1 and 25 cycles in Example 1 are shown in FIG. The battery capacity was calculated from the charge / discharge curve.
-Discharge conditions: Discharge was performed at a constant current of 0.1 mA / cm ^{2 until the battery voltage reached 0.2 V.}
-Charging conditions: The battery was charged with a constant current of ^{0.1 mA / cm 2 until the battery voltage reached 2.0 V.}

(2) Cyclic Voltamogram Electrochemical measurement was carried out under the following conditions for each metal-air battery obtained as described below. At that time, the measured electrode area was 1 cm ² for both electrodes.

Cyclic voltammetry (0 to 2.0 V) was adopted as the measuring method. The measurement was performed by a bipolar method (aluminum negative electrode and air electrode). As a measuring device, a galvanostat (SP-150, manufactured by BioLogic (France)) was used. The measurement was carried out at a temperature of 25 ° C. (standing in a constant temperature bath for 3 hours before the start of measurement), normal atmospheric pressure atmosphere conditions, and a scanning speed of 10 mV / s. The cyclic voltammograms after 1 and 25 cycles in Example 1 are shown in FIG.

(3) Evaluation of rust prevention property Each metal-air battery obtained as described below was evaluated for rust prevention property under the following conditions. Specifically, after evaluating the cyclic characteristics of each metal-air battery (n = 12) three times, the current collector of the air electrode is taken out, and the color tone of the current collector surface changes visually (presence or absence of rust). It was confirmed. The evaluation results are shown in Table 1.

If the color is the same as before the test and no substantial change is observed, ◎
If 1 to 4 out of 12 are rusted, ○
If 5 to 8 out of 12 are rusted, △
If 9 to 12 out of 12 are rusted, ×
<Example 1>
(Negative electrode)
A commercially available metallic aluminum (Al A1050, purity 99.5%) having a thickness of 1 mm was cut into a diameter of 10 mm to produce a negative electrode.

(Air pole)
A commercially available titanium nitride / polyvinylidene fluoride (PVDF) (Sigma-Aldrich Co.) / N-methylpyrrolidone solution as an air electrode catalyst material is weighed at a mass ratio of 1: 1: 2, and after sufficient mixing, it is combined with a current collector. The titanium metal mesh (opening 200 μm) was coated with a thickness of 100 μm and dried at 120 ° C. for 1 hr to form a catalyst layer on the titanium metal mesh. The prepared catalyst layer was impregnated with a commercially available 0.2% aqueous solution of Pt nanocolloid (GS NC Pt, manufactured by GS Alliance Co., Ltd.) at room temperature for 2 hours. Then, it was processed to φ10 mm and used as an air electrode.

(Electrolytes)
A mixture of urea (Sigma Aldrich Co., purity 99%) and AlCl ₃ (Sigma Aldrich Co., purity 99%) (molar ratio 1: 1) is mixed at room temperature for at least 2 hours until a liquid reaction product is formed. Then, an electrolyte containing a deep eutectic solvent was prepared. The electrolyte was impregnated into a separator (φ10 mm, thickness 100 μm, material: gauze) and used.

(Manufacturing of metal-air batteries)
First, the negative electrode manufactured above was fitted into one side of a fluororesin mold having an inner diameter of 10 mm and a length of 30 mm. Next, the gauze impregnated with the electrolyte produced above was placed on the negative electrode. Next, the metal-air battery was manufactured by arranging the air electrodes manufactured above so that the catalyst layer side was in contact with the gauze so that air bubbles did not enter.

<Example 2>
In Example 1, a metal-air battery was manufactured under the same conditions as in Example 1 except that the positive electrode current collector was a molybdenum metal mesh (opening 200 μm).

<Example 3>
In Example 1, a metal-air battery was manufactured under the same conditions as in Example 1 except that the positive electrode current collector was an Inconel metal mesh (opening 200 μm).

<Example 4>
In Example 1, a metal-air battery was manufactured under the same conditions as in Example 1 except that the positive electrode current collector was carbon paper (opening 200 μm).

<Example 5>
A metal-air battery was manufactured under the same conditions as in Example 1 except that titanium nitride was a carbon alloy (commercially available) doped with B, N, and S (boron, nitrogen, and sulfur) in Example 1.

<Example 6>
Example 1 except that titanium nitride was a perovskite-type composite oxide (La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O ₃ (LSCF, Sigma Aldrich Co.)) in Example 1. A metal-air battery was manufactured under the same conditions as above.

<Example 7>
In Example 1, a metal-air battery was manufactured under the same conditions as in Example 1 except that the positive electrode current collector was a tungsten metal mesh (opening 200 μm).

<Example 8>
In Example 1, a metal-air battery was manufactured under the same conditions as in Example 1 except that the Pt nanocolloid was a commercially available graphene quantum dot (GS Alliance Co., Ltd., GS QD Graphene).

<Example 9>
Under the same conditions as in Example 1, except that the Pt nanocolloid was used as a commercially available carbon-based material derived from a metal-organic framework (MOF) (GS Alliance Co., Ltd., GS MOF Mill 100 (fe)). Manufactured a metal-air battery.

<Example 10>
In Example 1, a metal-air battery was manufactured under the same conditions as in Example 1 except that the electrolyte of Example 1 was solidified as follows.

(Electrolytes)
The electrolyte containing the deep eutectic solvent obtained in Example 1 and a carboxymethyl cellulose polymer (manufactured by Daicel FineChem) were mixed at 25 ° C. for 2 hours (mass ratio: electrolyte: polymer = 1: 1), and then. A solid electrolyte was prepared by applying it on a metal negative electrode and drying it.

<Comparative example 1>
In Example 1, a metal-air battery was manufactured under the same conditions as in Example 1 except that the positive electrode current collector was a stainless metal mesh (opening 200 μm) and no Pt nanocolloid was supported.

<Comparative example 2>
In Example 1, the metal-air battery was used under the same conditions as in Example 1 except that the positive electrode current collector was a nickel metal mesh (opening 200 μm), the Pt nanocolloid was not supported, and the electrolyte was prepared as follows. Manufactured.

(Electrolytes)
A mixture of 1-butyl-3-methylimidazolium chloride (Sigma Aldrich Co., purity 99%) and AlCl ₃ (molar ratio 1: 1) was used as the electrolyte.

<Comparative example 3>
In Example 1, a metal-air battery was manufactured under the same conditions as in Example 1 except that the Pt nanocolloid was not supported and the electrolyte was prepared as follows.

(Electrolytes)
A mixture of 1-butyl-3-methylimidazolium chloride (Sigma Aldrich Co., purity 99%) and AlCl ₃ (molar ratio 1: 1) was used as the electrolyte.

The above results are shown in Table 1 and FIGS. 2 to 3.

(Results and discussion)
As shown in Table 1, when Examples 1 to 9 and Comparative Examples 1 to 3 are compared, in Examples 1 to 9, although the electrolytic solution contains a corrosive component (AlCl _3, etc.), it is contained. However, corrosion of the positive electrode current collector could be suppressed, and the battery could last longer. Further, in Examples 1 to 9, by supporting various catalysts, the redox reaction could be increased and the electrical characteristics such as the battery capacity could be improved.

With respect to Example 10, since this is an all-solid-state battery, it is presumed that the interfacial resistance of the electrode / electrolyte is high and the battery capacity is smaller than that of Examples 1 to 9. However, it is worthwhile that Example 10 is an all-solid-state type. In Example 10, for example, although not shown in Table 1, it is said that the redox reaction can be sufficiently increased and the electrical characteristics such as the battery capacity can be improved as compared with the all-solid-state comparative example. think. Further, in Example 10, although the electrolytic solution contains a corrosive component (AlCl _3, etc.), the corrosion of the positive electrode current collector can be suppressed and the battery can be made to last longer.

The aluminum air battery AlCl ₄ ^- or Al ₂ Cl ₇ ^- is said to charge carriers, by the following reaction, for example the negative electrode, the redox of aluminum proceeds, estimated to be can be charged and discharged ing.
4Al ₂ Cl ₇ ⁻ + 3e ⁻ ⇔ Al + 7AlCl ₄ ⁻
Further, on the air electrode side, it is presumed that the redox reaction of oxygen is proceeding by the following two-electron reaction and four-electron reaction.
2-electron reaction ^{_{O 2 + 2H + + 2e -}} → 2H 2 O 2
^{_{H 2 O 2 + 2H + +}} 2e - → 2H 2 O
4-electron reaction ^{_{O 2 + 4H + + 4e -}} → 2H 2 O

1 Negative electrode 2 Electrolyte 3 Air electrode

Claims (9)

A metal-air battery having a negative electrode, an air electrode, and an electrolyte interposed between the negative electrode and the air electrode.
The air electrode has a catalyst layer containing an air electrode catalyst material and a positive electrode current collector.
The positive electrode current collector contains at least one selected from the group consisting of titanium metal, molybdenum metal, nickel alloy, tungsten metal, zirconium metal, tantalum metal and carbon metal.
The air electrode catalyst material contains at least one selected from the group consisting of non-oxide ceramics, carbon-based materials, and composite oxides.
Further, the air electrode catalyst material includes a noble metal nanocolloid, a carbon quantum dot, a graphene quantum dot, a metal organic structure (MOF), a carbon material derived from the metal organic structure (MOF), and a metal organic structure (MOF). A metal-air battery supported by at least one selected from the group consisting of oxide-based materials derived from). The metal-air battery according to claim 1, wherein the positive electrode current collector has a porous structure. The metal-air battery according to claim 1 or 2, wherein the non-oxide ceramic contains metal carbides, nitrides, borides, oxynitrides, carbonitrides, or silicides. The metal-air battery according to claims 1 to 3, wherein the carbon-based material contains carbon nanotubes, graphene, graphite, activated carbon, or a carbon alloy. The metal-air battery according to any one of claims 1 to 4, wherein the composite oxide is a perovskite-type composite oxide. The metal-air battery according to any one of claims 1 to 5, wherein the electrolyte contains an ionic liquid or a deep eutectic solvent. The metal-air battery according to any one of claims 1 to 6, wherein the electrolyte is a solid state. The metal-air battery according to any one of claims 1 to 7, wherein the negative electrode contains aluminum. The metal-air battery according to any one of claims 1 to 8, which is for a primary battery or a secondary battery.

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