JP2021089802A - Air electrode, metal-air battery and method for manufacturing air electrode - Google Patents

Abstract

To prevent peeling between a water-repellent film and a catalyst layer in an air electrode and prevent the leakage of an electrolyte, thereby achieving an improvement in battery performance.SOLUTION: An air electrode 1 includes a water-repellent film 11, a current collector 12 and a catalyst layer 13. The catalyst layer 13 has a plurality of through holes 131 penetrating therethrough in a thickness direction. In each of the plurality of through holes 131, opening diameters r1, r2 opening on the front and back surfaces of the catalyst layer 13, respectively, and a pore diameter R within a layer, which is a pore diameter inside the catalyst layer 13, are different from each other, and the pore diameter R within a layer has the maximum diameter among the opening diameter r1 on the front surface side, the opening diameter r2 on the back surface side and the pore diameter R within a layer.SELECTED DRAWING: Figure 1

Description

The present invention relates to an air electrode, a metal-air battery including the air electrode, and a method for manufacturing the air electrode.

Metal-air batteries use oxygen in the air as the positive electrode acting substance of the battery. In this type of metal-air battery, one surface of the air electrode is in contact with the electrolyte, while the other surface is in contact with the air. Normally, the air electrode is provided with an air hole for taking in air, and the inside of the air electrode has a porous structure. As the electrolyte, for example, an alkaline aqueous solution that reduces the surface tension of water to increase its permeability is used.

Conventionally, there has been a problem that the electrolyte permeates into the air electrode and further leaks to the outside of the air electrode depending on the structure of the air electrode and the properties of the electrolyte. If the electrolyte leaks out, the battery performance deteriorates, long-term reliability and long life cannot be ensured, and there are problems in terms of safety such as contact with the electrolyte.

To solve such a problem, it is conceivable to provide a water repellent film 65 on the outside of the catalyst layer 62 in addition to the catalyst layer 62 and the current collector 63 of the air electrode 61. However, the water-repellent film 65 makes it possible to suppress the leakage of the electrolyte 64 in the short term, but as shown in FIG. 6, even if the measures are taken, the electrolyte 64 that has penetrated into the catalyst layer 62 can be prevented. It may accumulate between the water-repellent film 65 and the catalyst layer 62, forming a gap at the interface between the water-repellent film 65 and the catalyst layer 62. When such a gap is generated, the electrolyte 64 accumulated between the catalyst layer 62 and the water-repellent film 65 reduces the amount of air supplied to the catalyst layer 62, and the electrode reaction of the catalyst layer 62 is hindered. There was a problem.

For example, Patent Document 1 discloses an air electrode having a catalyst layer in which a plurality of through holes are formed by piercing a needle from one surface to the other surface. In this air electrode, it is intended that the through hole enhances gas permeability.

JP-A-2002-110182

The air electrode disclosed in Patent Document 1 only considers gas permeability, and the possibility of electrolyte leakage from the through hole has not been examined. Therefore, since the electrolyte covers the surface of the catalyst layer, it becomes difficult for the air required for the reaction to reach the catalyst layer, which leads to deterioration of the battery life and still has a problem in terms of safety.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to prevent peeling of the water-repellent film and the catalyst layer and prevent leakage of electrolyte to improve battery performance. It is an object of the present invention to provide an air electrode having excellent reliability and safety, a metal-air battery including the air electrode, and a method for manufacturing the air electrode.

The solution of the present invention for achieving the above object is premised on an air electrode including a current collector, a water repellent film, and a catalyst layer arranged between the current collector and the water repellent film. As the air electrode, the catalyst layer has a plurality of through holes penetrating in the thickness direction, and the through holes have an opening diameter opening on the front surface and the back surface of the catalyst layer and a hole diameter inside the catalyst layer. It is characterized in that it has the largest diameter in the layer among the opening diameter on the front surface side, the opening diameter on the back surface side, and the inner hole diameter in the layer, which is different from the inner hole diameter.

Due to this specific matter, the through hole of the catalyst layer acts to return the electrolyte in the metal-air battery to the current collector side, and an air electrode having a structure in which the electrolyte does not accumulate between the catalyst layer and the water repellent film is formed. Can be configured. Therefore, at the air electrode, air can reach the catalyst layer through the water-repellent film, and the electrode reaction can proceed smoothly.

A metal-air battery provided with the air electrode is also within the scope of the technical idea of the present invention. That is, it is characterized in that it includes an air electrode, a metal electrode, and an electrolyte according to the above configuration.

As a result, the air electrode has a structure in which the electrolyte does not accumulate between the catalyst layer and the water-repellent film, so that the electrode reaction proceeds smoothly and the decrease in output as a metal-air battery is suppressed. , It is possible to extend the battery life.

Further, a method for manufacturing an air electrode for forming the air electrode is also within the scope of the technical idea of the present invention. That is, it has a current collector, a water-repellent film, and a catalyst layer arranged between the current collector and the water-repellent film, and the catalyst layer has a plurality of through holes penetrating in the thickness direction. A method for producing an air electrode, which includes a dissolution step of dissolving and removing the particles of a catalyst layer holding a plurality of isotropic particles made of a soluble substance to form through holes in the catalyst layer. It is characterized by.

According to this specific matter, it becomes possible to easily form a plurality of the through holes having the maximum inner diameter in the catalyst layer. Further, since the soluble particles can be dissolved by using the electrolyte constituting the metal-air battery, through holes can be efficiently formed in the catalyst layer, and productivity, reliability and safety can be obtained. It can be excellent in any of the above.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an air electrode which can prevent leakage of an electrolyte, enhance battery performance, and have excellent reliability and safety, and a metal-air battery provided with the air electrode. Further, according to the method for producing an air electrode of the present invention, it is possible to easily form an air electrode having a catalyst layer having through holes.

It is a partial cross-sectional view which shows the air electrode which concerns on embodiment of this invention. It is explanatory drawing which shows one step of the manufacturing method of the air electrode. It is explanatory drawing which shows the pressing process in the said manufacturing method of an air electrode. It is explanatory drawing which shows the melting process in the said manufacturing method of an air electrode. It is the schematic sectional drawing of the metal-air battery which concerns on embodiment of this invention. It is sectional drawing which shows the conventional air electrode.

Hereinafter, a method for manufacturing an air electrode, a metal-air battery, and an air electrode according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a partial cross-sectional view showing a schematic structure of an air electrode according to the present embodiment. 2 to 4 are explanatory views of a method for manufacturing an air electrode according to the present embodiment. FIG. 5 is a schematic cross-sectional view of the metal-air battery according to the present embodiment.

The air electrode 1 includes a water-repellent film 11, a current collector 12, and a catalyst layer 13 arranged between the current collector 12 and the water-repellent film 11. Further, the metal-air battery 2 of the present embodiment includes the air electrode 1, the metal electrode 3, and the electrolyte 4. In the following, for convenience, each layer constituting the air electrode 1 will be described with the surface on the water-repellent film 11 side as the front surface and the surface on the current collector 12 side as the back surface.

(Air pole)
The air electrode 1 is an electrode using oxygen gas as an electrode active material, and is an electrode containing a catalyst for an electrode reaction (oxygen reduction reaction) of the air electrode. The air electrode 1 may be the air electrode of the metal-air battery 2 (air electrode for a metal-air battery) or may be used for a fuel cell.

The air electrode 1 according to the present embodiment can be incorporated into a metal-air battery, for example, as in the metal-air battery 2 shown in FIG. The air electrode 1 is arranged so that the water repellent film 11 is on the air side. As a result, the electrolyte can be impregnated into the catalyst layer 13 from the metal electrode 3 side, and air can be supplied to the catalyst layer 13 from the water repellent film 11 side. As a result, it is possible to form a three-phase interface on the catalyst layer 13 in which the electrode reaction proceeds.

The current collector 12 of the air electrode 1 is a conductor that serves as a conductive path for supplying electrons to the surface of the catalyst particles in which the electrode reaction proceeds. By providing the catalyst layer 13 containing the catalyst particles on the current collector 12, the internal resistance of the air electrode 1 can be reduced, and the discharge characteristics of the metal-air battery 2 can be improved. Further, the current collector 12 is a member serving as a base material for forming the catalyst layer 13.

The current collector 12 can be a metal mesh or a perforated metal plate. The material of the current collector 12 can be, for example, metallic nickel, silver, gold, platinum or stainless steel. Further, the current collector 12 may be a nickel-plated metal mesh or a porous metal plate. For example, a metal mesh of nickel-plated iron or a perforated metal plate. As a result, it is possible to prevent the current collector 12 from being thermally damaged when the catalyst layer 13 is formed. Further, the current collector 12 can have alkali resistance, and it is possible to prevent the current collector 12 from being corroded by the alkaline electrolyte. When the current collector 12 is a porous metal plate, examples of the porous metal plate include expanded metal, punching metal, and porous metal foil.

The water-repellent film 11 is a film that allows air to pass through but does not allow water to pass through. The water-repellent film 11 has a hole through which air passes, and the inner wall of the hole has water repellency. Therefore, water can hardly enter this hole, but air can pass through this hole. The water-repellent film 11 can be a porous layer. The water-repellent film 11 may include, for example, a fluororesin porous film. The fluororesin porous membrane allows air to pass through, but hardly allows water to pass through.

The catalyst layer 13 is a porous layer containing catalyst particles, a conductive agent, and a binder. The electrode reaction of the air electrode 1 proceeds on the surface of the catalyst particles contained in the catalyst layer 13. The catalytic particles are particles having catalytic activity for an oxygen reduction reaction (electrode reaction). The material of the catalyst particles is, for example, metal oxide, silver and the like. The catalyst particles may be covered with a conductive agent adhering to the surface of the catalyst particles. The conductive agent may form a coated porous layer covering the surface of the catalyst particles. By coating the surface of the catalyst particles with a coated porous layer made of a conductive agent, electrons can be rapidly supplied to the surface of the catalyst particles in which the electrode reaction proceeds.

The conductive agent electrically connects the current collector 12 and the surface of the catalyst particles, and supplies electrons necessary for the electrode reaction to the surface of the catalyst particles. The conductive agent is, for example, carbon particles. Specifically, the material of the conductive agent is carbon black, carbon fiber, carbon nanotube, activated carbon, graphite or the like.

The binder is added to maintain the shape of the catalyst layer 13. The binder is, for example, a fluorine-based resin having excellent alkali resistance. Further, as the binder, polytetrafluoroethylene (PTFE), which binds particles while developing into a fibrous form, has excellent water repellency, and is stable against heat, can be used.

In a conventional ordinary air electrode, the water-repellent membrane and the catalyst layer are separated to form a gap at the interface between the water-repellent membrane and the catalyst layer, and the electrolyte is accumulated in the gap, so that the water-repellent membrane side is transferred to the catalyst layer. There is a problem that the amount of air supplied to the metal-air battery is reduced and the output of the metal-air battery is reduced.

On the other hand, the catalyst layer 13 constituting the air electrode 1 according to the present embodiment has a plurality of through holes 131 penetrating in the thickness direction. As shown in FIG. 1, the through hole 131 of the catalyst layer 13 has an inner wall surface formed in a curved surface shape and has a shape of opening on the front surface and the back surface of the catalyst layer 13. As shown in FIG. 4, these through holes 131 can eventually become a passage for the electrolyte 4, and act to return the electrolyte 4 to the current collector 12 side again. Therefore, the catalyst layer 13 and the water-repellent film 11 It can be prevented from accumulating between and.

More specifically, as shown in FIG. 1, each through hole 131 has opening diameters (pore diameters) r1 and r2 opened on the front surface and the back surface of the catalyst layer 13, respectively, and inside the layer which is the pore diameter inside the catalyst layer 13. It is formed so as to be different from the pore diameter R. The pore diameter R in the layer is larger than the opening diameter r1 on the front surface side and the opening diameter r2 on the back surface side.

Further, the through hole 131 has the maximum diameter in the in-layer hole diameter R. As shown in FIG. 1, the through hole 131 has an in-layer hole diameter R having a maximum diameter in a substantially intermediate portion in the thickness direction of the catalyst layer 13. The maximum diameter of the pore diameter R in the layer is larger than the thickness T of the catalyst layer 13.

The curved surface of the inner wall surface of the through hole 131 has a shape that gradually bulges from the water-repellent film 11 side to the inside of the catalyst layer 13 and from the current collector 12 side to the inside of the catalyst layer 13. As will be described later, this curved surface is due to the isotropic soluble particles (particles) 15 held in the catalyst layer 13, and the through holes 131 are hollow portions formed by the soluble particles 15. ..

(Metal-air battery)
When applied to the metal-air battery 2, the air electrode 1 having a plurality of through holes 131 as described above can be housed in the battery case 5 and serve as a positive electrode (cathode) as shown in FIG. The battery case 5 is an outer container that houses an air pole 1 and a metal pole 3, and a large number of air intake ports 51 are provided on the air pole 1 side. The battery case 5 is capable of taking in air into the inside through these air intake ports 51.

Examples of the metal-air battery 2 include a zinc-air battery, a lithium-air battery, a sodium battery, a calcium-air battery, a magnesium-air battery, and an aluminum-air battery. Of these, when the metal-air battery 2 is a zinc-air battery, for example, metallic zinc can be used for the metal electrode 3, and an aqueous potassium hydroxide solution can be used for the electrolyte 4.

The air electrode 1 is laminated in the order of the water repellent film 11, the catalyst layer 13, and the current collector 12 from the battery case 5 side. As described above, the catalyst layer 13 has a plurality of through holes 131 having a large inner hole diameter R. Therefore, even if there is an electrolyte 4 that has penetrated between the water-repellent film 11 and the catalyst layer 13 from the inside of the metal-air battery 2, it returns to the current collector 12 side again through the through hole 131 and the metal-air battery 2 Stay inside the. Therefore, the electrolyte 4 is prevented from accumulating between the water-repellent film 11 and the catalyst layer 13, and is prevented from leaking to the outside of the catalyst layer 13.

As a result, peeling of the water-repellent film 11 and the catalyst layer 13 can be prevented, no gap is formed at the interface between the water-repellent film 11 and the catalyst layer 13, and air is passed through the water-repellent film 11 to the catalyst layer 13. Can be reached. The electrode reaction proceeds smoothly in the catalyst layer 13, and leakage of the electrolyte 4 can be suppressed for a long period of time. As a result, in the metal-air battery 2 provided with the air electrode 1, a decrease in output is suppressed, and the battery life can be extended.

(Manufacturing method of air electrode)
A method for manufacturing the air electrode 1 having the above configuration will be described. In this method of manufacturing the air electrode 1, a plurality of through holes 131 are provided in the catalyst layer 13 by utilizing the soluble particles 15. The soluble particles 15 are added to the catalytic paste 14.

As shown in FIG. 2, a large number of soluble particles 15 are added to the catalyst paste 14, kneaded, molded into a sheet, and dried in a state in which the soluble particles 15 are dispersed and arranged. As a result, a sheet-shaped precatalyst layer 130 in which the soluble particles 15 are dispersed and held is obtained. The soluble particle 15 is a particle made of a soluble substance. In order to distinguish the catalyst layer in the state before forming the through hole 131 from the catalyst layer 13 having the through hole 131 in the air electrode 1, it is referred to as the pre-catalyst layer 130 here. That is, the pre-catalyst layer 130 corresponds to the catalyst layer 13 in a state where the soluble particles 15 are held in the through holes 131.

The thickness t of the pre-catalyst layer 130 is common to the thickness T of the catalyst layer 13, and is preferably 0.1 mm or more and less than 1 mm. More preferably, the thickness t is 0.4 mm or more and less than 0.7 mm. If it is less than 0.1 mm, the amount of catalyst contained in the catalyst layer 13 decreases, so that the discharge voltage drops. If it is 1 mm or more, the distance from the inside of the catalyst layer 13 to the current collector 12 becomes long when the electrolyte 4 accumulated between the water-repellent film 11 and the catalyst layer 13 is returned, and from the viewpoint of suppressing a decrease in output. Not preferable.

The soluble particles 15 are isotropic and have an elastically deformable spherical or substantially spherical outer shape. As shown in FIG. 2, the soluble particles 15 preferably have a diameter equal to or larger than the thickness t of the precatalyst layer 130. The soluble particles 15 may have a diameter larger than the thickness t of the precatalyst layer 130 and may be partially exposed from the catalyst paste 14.

The amount of the soluble particles 15 added may be 0.5% or more and less than 4% in volume fraction with respect to the total volume of the conductive agent and the catalyst particles of the catalyst paste 14 and the volumes of the soluble particles 15. preferable. When the volume fraction is less than 0.5%, the number of through holes 131 due to the soluble particles 15 is small, and it becomes difficult for the electrolyte 4 to return from the catalyst layer 13 to the current collector 12 side. Further, when the volume fraction is 4% or more, the catalyst particles contained in the catalyst layer 13 are reduced, so that the discharge voltage may decrease or the catalyst layer 13 may be easily cracked, thereby stabilizing the manufacturing quality. It is not preferable from the viewpoint of

As the soluble substance constituting the soluble particle 15, a substance that dissolves in water, an alkaline aqueous solution, or an organic solvent can be used. For example, examples of substances that dissolve in water include potassium hydroxide and sodium chloride for inorganic substances, and sucrose and fructose for organic substances. Examples of the substance that dissolves in the alkaline aqueous solution include calcium oxide and aluminum oxide for inorganic substances, polyester for organic substances, and photosensitive polyimide. Examples of the substance that dissolves in an organic solvent include rubber.

Next, as shown in FIG. 3, the precatalyst layer 130 in which the soluble particles 15 are dispersed and held is sandwiched between the water-repellent membrane 11 and the current collector 12 and pressure-bonded (pressing step). As a result, the front air electrode 10 in which the water-repellent film 11, the front catalyst layer 130, and the current collector 12 are stably joined and integrated is obtained.

In the pressing step, the soluble particles 15 held in the pre-catalyst layer 130 are sandwiched between the water-repellent film 11 and the current collector 12 and deformed, and are contained within the thickness t of the pre-catalyst layer 130. The soluble particles 15 are in a state of being partially in contact with both the water-repellent film 11 and the current collector 12.

Next, the soluble particles 15 are dissolved and removed to form a catalyst layer 13 having through holes 131 (dissolution step). For example, the front air electrode 10 and the metal electrode 3 are arranged in the battery case 5, and the electrolyte 4 is sealed. As shown in FIG. 4, the soluble particle 15 is dissolved by the electrolyte 4 to form a hollow portion, and a through hole 131 having the maximum diameter in the in-layer pore diameter R can be formed. Further, before arranging the soluble particles 15 in the battery case 5, the soluble particles 15 may be immersed in a solvent corresponding to the solubility and removed to form a catalyst layer 13 having through holes 131.

As mentioned above, the soluble substance is a substance that dissolves in water, an aqueous alkaline solution, or an organic solvent. In the dissolution step, the soluble particles 15 are dissolved in water, an aqueous alkaline solution, or an organic solvent corresponding to the solubility. For example, when the soluble particles 15 are made of an alkali-soluble resin, the soluble particles 15 are dissolved by the electrolyte (electrolyte-containing solution) 4 which is an alkaline aqueous solution in the dissolution step.

When the soluble particles 15 are made of sodium chloride that is soluble in water, the safety in the dissolution step is enhanced and the workability can be improved. When potassium hydroxide is used as a substance that dissolves in water, when water is injected into the battery case 5, potassium hydroxide dissolves and can function as the electrolyte 4 of the metal-air battery 2. When sucrose or fructose is used as a substance that dissolves in water, raising the temperature of the solvent water enables safe and rapid dissolution and increases the work speed.

When the soluble substance is a substance that dissolves in the alkaline aqueous solution, the alkaline aqueous solution is usually an electrolytic solution used as the electrolyte 4 of the metal-air battery 2, so that the soluble particles 15 are dissolved by injecting the solution into the battery case 5. The productivity of the metal-air battery 2 can be improved. Further, when polyester is used as the substance to be dissolved in the alkaline aqueous solution, the shape of the soluble particles 15 can be easily formed into a spherical shape, and the through hole 131 having the maximum diameter in the inner pore diameter R can be easily formed.

When photosensitive polyimide is used as a substance that dissolves in an alkaline aqueous solution, it is preferable to keep the soluble particles 15 in an insoluble state without exposing them to light at the stage of the precatalyst layer 130 up to the dissolution step. As a result, it is possible to prevent the shape of the catalyst layer 13 from being deformed due to the mixing of the alkaline aqueous solution at an unexpected timing. When calcium oxide or aluminum oxide is used as a substance that dissolves in an alkaline aqueous solution, in addition to the effect of forming through holes 131 in the catalyst layer 13, it is used as ions in the electrolyte 4 when the metal-air battery 2 is injected. It can also be expected to have the effect of dissolving and suppressing self-corrosion of the zinc negative electrode.

When a substance that dissolves in an organic solvent is used as the soluble substance, the organic solvent is more volatile than the aqueous solution, so that it is easy to dry after forming the through holes 131, and the state of the catalyst layer 13 provided with the through holes 131. By arranging it in the metal-air battery 2, it can be stored for a long period of time without encapsulating the electrolyte 4. When rubber that dissolves in an organic solvent is used, it has excellent elasticity, so that the sheet-like molding process of the precatalyst layer 130 becomes easy.

By such a melting step, a catalyst layer 13 having a plurality of through holes 131 is obtained. The air electrode 1 has a structure in which a water-repellent film 11, a catalyst layer 13, and a current collector 12 are laminated in this order from the outside, and is formed by having a plurality of through holes 131 penetrating in the thickness direction in the catalyst layer 13. .. Further, in the dissolution step, since the soluble particles 15 can be dissolved by using the electrolyte 4 constituting the metal-air battery 2, the through holes 131 can be efficiently and easily formed in the catalyst layer 13.

In the air electrode 1, the through hole 131 prevents the water-repellent film 11 and the catalyst layer 13 from peeling off, and air is passed through the water-repellent film 11 without creating a gap at the interface between the water-repellent film 11 and the catalyst layer 13. Can reach the catalyst layer 13. A smooth electrode reaction is possible in the catalyst layer 13, and leakage of the electrolyte 4 can be suppressed for a long period of time. As a result, the output decrease of the metal-air battery 2 provided with the air electrode 1 is suppressed, and the battery life can be extended.

The method for manufacturing the air electrode 1, the metal-air battery 2, and the air electrode 1 is not limited to the configuration shown in the above embodiment, and can be implemented by various other forms.

The technical scope of the present invention is not to be construed solely by the above-described embodiment, but is based on the scope of claims. In addition, the technical scope of the present invention includes all modifications within the meaning and scope equivalent to the claims.

(Example 1)
The catalyst layer 13 contains a metal oxide as a catalyst, carbon having conductive and catalytic functions, and a fluororesin (an example of a binder) that binds them. In producing the catalyst layer 13, MnO ₂ powder (manufactured by Chuo Denki Kogyo Co., Ltd., trade name: CMD-K200), carbon black (manufactured by Denka Co., Ltd., trade name: Denka Black), and a binder, which are catalyst particles, are used. As a binder (PTFE dispersion "D-210C" manufactured by Daikin Industries, Ltd.) was used as a raw material, and polyester particles as soluble particles 15 and water were mixed with a planetary mixer to prepare a mixture. A was prepared. Further, this mixture A was placed in a mortar and kneaded to prepare a dumpling-shaped kneaded product B. Then, the kneaded product B was formed into a sheet by a roll rolling mill to prepare the precatalyst layer 130.

In the step of producing the air electrode 1, the water repellent film 11, the precatalyst layer 13, and the current collector 12 (Ni mesh manufactured by Nirako Co., Ltd., opening # 20) are stacked in this order and pressed at room temperature to integrate them. Let (press process). Here, the press pressure was 2.15 kN / cm ² , and the press time was 2 seconds.
Zinc is dissolved by immersing the above-mentioned air electrode 1 in a 7M KOH aqueous solution that acts as an electrolyte 4 for 24 hours (dissolution step), and then combining a zinc plate that is a metal electrode 3. Created an air battery.

(Comparative Example 1)
A zinc-air battery was prepared in the same manner as in Example 1 except that the soluble particles 15 were not used and no dissolution step was performed.

For the zinc-air batteries of Example 1 and Comparative Example 1 ^{, voltage measurement was performed at a constant current of 30 mA / cm 2} , and the energization time until the obtained voltage fell below 0.8 V was measured. This energizing time was defined as the battery life. In Comparative Example 1, the battery life was 50 hours and peeling of the catalyst layer and the water-repellent film was observed after 50 hours, whereas in Example 1, the battery life was 1000 hours and 50 hours later. However, no peeling between the catalyst layer and the water-repellent film was observed.

The present invention can be suitably used for a metal-air battery used as one of power supply devices and an air electrode constituting the metal-air battery.

1 Air pole 2 Metal-air battery 3 Metal pole 4 Electrolyte 5 Battery case 11 Water repellent film 12 Current collector 13 Catalyst layer 131 Through holes r1, r2 Opening diameter R Layer inner pore diameter 14 Catalyst paste 15 Soluble particles (particles)
10 Front air electrode 130 Front catalyst layer

Claims (11)

An air electrode including a current collector, a water-repellent film, and a catalyst layer arranged between the current collector and the water-repellent film.
The catalyst layer has a plurality of through holes penetrating in the thickness direction, and has a plurality of through holes.
The through hole has an opening diameter that opens on the front surface and the back surface of the catalyst layer and an inner hole diameter that is a hole diameter inside the catalyst layer, and is different from the opening diameter on the front surface side, the opening diameter on the back surface side, and the opening diameter. An air electrode having the maximum diameter of the inner pore diameter in the layer. In the air electrode according to claim 1,
An air electrode characterized in that the inner wall surface of the through hole has a curved surface shape. In the air electrode according to claim 2.
The curved surface of the inner wall surface has a shape that bulges from the front surface to the inside of the catalyst layer and from the back surface to the inside of the catalyst layer. In the air electrode according to any one of claims 1 to 3,
The through hole is an air electrode characterized in that the maximum diameter of the hole in the layer is larger than the thickness of the catalyst layer. In the air electrode according to any one of claims 1 to 4.
The through hole is an air electrode characterized by being a cavity formed by isotropic particles held in the catalyst layer. A metal-air battery comprising the air electrode according to any one of claims 1 to 5, a metal electrode, and an electrolyte. An air electrode having a current collector, a water-repellent film, and a catalyst layer arranged between the current collector and the water-repellent film, and the catalyst layer has a plurality of through holes penetrating in the thickness direction. It is a manufacturing method of
A method for producing an air electrode, which comprises a dissolution step of dissolving and removing the particles of a catalyst layer holding a plurality of isotropic particles made of a soluble substance to form through holes in the catalyst layer. .. In the method for manufacturing an air electrode according to claim 7.
The soluble substance is a substance that dissolves in water, an aqueous alkaline solution, or an organic solvent.
A method for producing an air electrode, which comprises dissolving the particles in water, an alkaline aqueous solution, or an organic solvent in the dissolution step. In the method for manufacturing an air electrode according to claim 8.
The particles are made of alkali-soluble resin
The dissolution step is a method for producing an air electrode, which comprises dissolving the particles with an electrolyte-containing solution which is an alkaline aqueous solution. In the method for manufacturing an air electrode according to any one of claims 7 to 9,
A method for producing an air electrode, wherein the particles are elastically deformable spheres or substantially spheres. In the method for manufacturing an air electrode according to any one of claims 10.
A method for producing an air electrode, wherein the particles have a diameter equal to or greater than the thickness of the catalyst layer.

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