JPS5994376A - Manufacture of air electrode - Google Patents

Abstract

PURPOSE:To obtain a thin air electrode which can be subjected to heavy load discharge over a long period and has an excellent preservation performance by forming a thin film of a metal oxide having oxygen adsorbing ability on the gas- side surface of a porous electrode base by vapor deposition or sputtering. CONSTITUTION:A thin film of a metal oxide having oxygen adsorbing ability is formed on the gas-side surface of a porous electrode base having both a current collecting function and the ability to electrochemically reduce oxygen gas by vapor deposition or sputtering. For instance, after a Raney-nickel plate (200mum thickness) having a mean hole diameter of 5mum and a porosity of 80% and used as an electrode base is set on a sputtering device, a thin film of a metal oxide having oxygen adsorbing ability such as SnO2 or Cu2O is formed on one surface of the Raney-nickel plate by using the metal oxide as a target. Following that, the thus obtained plate is subjected to cathodic polarization by immersing it in 2% palladium chloride solution so as to deposit palladium in a thickness of about 0.5mum over the entire surface of the plate including the holes of the Raney-nickel plate.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a method for manufacturing an air electrode for a hydrogen/oxygen fuel cell, a metal/air battery, or an oxygen sensor. ) This invention relates to a method for producing an air electrode that is capable of heavy load discharge and has excellent storage performance.

[Technical background of the invention and its problems]

Conventionally, gas diffusion electrodes have been used as air electrodes in various fuel cells, air metal batteries including air/zinc batteries, galvanic oxygen sensors, and the like. Initially, floating porous electrodes with a uniform pore size distribution were used as gas diffusion electrodes, but recently, they have been developed to have electrochemical reduction ability for oxygen gas (ionize oxygen) and A porous electrode body that also has a current collector function,
An electrode having a two-layer structure consisting of a thin film-like water-repellent layer integrally attached to the gas-side surface of the electrode body is often used.

- In this case, the electrode body mainly consists of oxygen gas reduction JM4
Low-pressure nickel tungstic acid; tungsten carbide coated with palladium and cobalt; nickel; silver; platinum; palladium, etc., supported on a conductive powder such as activated carbon powder; After adding a binder, the binder is integrated with a porous metal body, a porous carbon body, a nonwoven fabric of carbon fiber, or the like.

However, the water-repellent layer attached to the gas side surface of the main body of the shell is mainly fluorine such as polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, and ethylene-tetrafluoroethylene copolymer. resin,
Or a thin film composed of a resin such as polypropylene, for example, a sintered body of these resin powders with a particle size of 0.2 to 40 μm; A paper-like thing made by heating the fibers of these resins and making them into a nonwoven fabric; Fiber cloth-like products; parts of these resin powders replaced with fluorinated graphite; film-like products made by pressing these fine powders together with pore-forming agents, lubricating oil, etc., and then heating them, or rolls. It is a porous thin film with distributed micropores, such as a film that is not heat-treated after pressurization.

However, in the air electrode of the conventional structure described above,
The water layer attached to the gas side surface of the prisoner body is impermeable to electrolyte, but not to air or water vapor in the air.

Therefore, for example, water vapor in the air may pass through the water-pumping layer and enter the main body, diluting the electrolyte9, or conversely, water in the electrolyte may radiate from the water-pumping layer as water vapor. Otherwise, the electrolyte may be concentrated. - As a result,
This causes a situation in which the concentration of the electrolyte fluctuates, making it impossible to maintain stable discharge for a long period of time.

When carbon dioxide gas in the air passes through the water-pumping layer, enters the electrode body, and is adsorbed by the active layer, the electrochemical reduction ability for oxygen gas at that location decreases, and heavy load discharge is inhibited. In addition, when the electrolyte is an alkaline electrolyte, phenomena such as deterioration of the electrolyte, decrease in concentration, or passivation of the zinc cathode when the cathode is zinc are caused. Furthermore, in the active layer (the porous part of the electrode body), carbonate is generated to block the pores and reduce the area where electrochemical reduction takes place, thereby inhibiting heavy load discharge.

If the manufactured battery is stored or used for a long period of time, the performance of the battery will deteriorate from the design standard. A battery has been proposed in which a layer of a moisture absorbent such as calcium chloride or a carbon dioxide gas absorbent such as alkaline earth metal hydroxide is further provided on the side (air side). Although it is possible to prevent such inconvenient situations to some extent, it is not an essential solution because after a certain period of time, these absorbents reach a saturated state and lose their absorption capacity, and the effect disappears. do not have.

[Purpose of the invention]

The present invention solves the above-mentioned deficiencies of the conventional structure, prevents water vapor or carbon dioxide from entering the electrode body, and therefore enables long-term heavy load discharge and improves storage performance. The purpose of this invention is to provide a method for manufacturing an excellent thin air electrode.

[Summary of the invention]

The air electrode of the present invention has, first of all, a porous electrode body that has an electrochemical reduction ability for oxygen gas and also has a current collector function; A thin film of a metal oxide having oxygen adsorption ability is integrally attached to the gas side surface of the electrode body directly or via a porous film, and the method for manufacturing the same includes: A metal oxide having an oxygen adsorption ability is applied to the gas side surface of the porous electrode body, which has an electrochemical reduction ability for oxygen gas and also has a current collector function, by a sputtering source using a vapor deposition method or a sputtering method. Alternatively, a thin film of the metal oxide is formed by depositing the reaction tank gas as an inert gas containing or not containing 10% or less of oxygen. A metal oxide having oxygen adsorption ability is deposited on one side of a porous film having micropores of 0.1 μm or less by vapor deposition or sputtering in the same manner as described above, and a thin layer of the metal oxide is formed. A layer is formed, and then the other surface of the porous membrane is pressed onto the gas side surface of a porous electrode body that has an electrochemical reduction ability for oxygen gas and also has a current collector function. It is characterized by being integrated.

The second is that it has electrochemical reduction ability for oxygen gas,
In addition, a water-lifting layer and a thin layer of a metal oxide having oxygen adsorption ability are integrally formed in this order on the gas-side surface of the porous electrode body, which also functions as a current collector, directly or via a porous membrane. The first method for manufacturing it is to add a porous electrode to the gas side surface of the porous electrode body, which has an electrochemical reducing ability for oxygen gas and also has an assembly function. A water-lifting layer is formed by a vapor deposition method or a sputtering method,
Furthermore, a metal oxide having an oxygen adsorption ability is deposited on the water-lifting layer by vapor deposition or sputtering as a sputtering source or vapor deposition source, and an inert gas containing or not containing 10 or less gases is used as a reaction tank gas. The second feature is that the thin layer of the metal oxide is formed by depositing the metal oxide with a pore size of 0.
．． A water repellent layer is formed on one side of a porous film having micropores of 1 μm or less by vapor deposition or sputtering, and a metal oxide having oxygen adsorption ability is further formed on the water repellent layer by vapor deposition or sputtering. A thin layer of the membrane is formed in the same manner as described above, and then the other side of the porous membrane is coated with a porous membrane that has a quasi-vapor chemical reducing ability for oxygen gas and also has a concentration function. It is characterized by being pressure-bonded to the gas side surface of the electrode body.

First, the electrode body used in the air electrode of the present invention is I'11
．． It is a porous body that has the ability to chemically reduce elementary gases (ionize oxygen gas) and is electrically conductive. Specifically, outside K, silver filters, Raney nickel, sintered bodies of silver or nickel, various foamed metals, compressed bodies of nickel-plated fine stainless steel wire, and gold, palladium, silver, etc. Examples include porous metal bodies made by plating. At this time, the reducing product ions of oxygen gas generated by the electrode reaction proceeding within the pores of the electrode body are quickly removed from the pores (reaction region), for example, 50 m1v'.
In order to smoothly continue heavy load discharge of Cl/1 or more,
The pore diameters of the pores in the electrode body are preferably distributed in a range of about 0.1 to ]0 μm.

The air electrode of the present invention has a water repellent layer and an oxygen absorbing layer in which a thin layer of a metal oxide having oxygen adsorption ability is laminated on the gas side surface of the electrode body directly or via a porous membrane. It has a structure in which thin layers of metal oxides with adsorption ability are laminated in this order.

In the present invention, the material constituting the water repellent layer may be any material as long as it has electrolyte resistance and water repellency.
For example, polytetrafluoroethylene (PTFE), fluoroethylene propylene (FDP), polyphenylene oxide (PPO), polyphenylene sulfide (PPS)
), polyethylene (PE), polypropylene (PP
), copolymers thereof, or mixtures thereof.

The thickness of the water repellent layer is preferably in the range of 0.01 to 1.0 μm; if it is less than 0.01 μm, pinholes will increase in the formed water repellent layer and the water repellent effect will decrease. Moreover, the mechanical strength of the entire layer decreases, making it easy for phenomena such as breakage to occur.If the thickness exceeds 1.0 μm, the amount of acid supplied to the electrode becomes insufficient, making it difficult for the resulting electrode to discharge under heavy load.

The metal oxide having oxygen adsorption ability used in the present invention has the property of adsorbing oxygen as molecules (02) or ions (0□-, o''-, o2-) on the surface and inside of the metal oxide. Specifically, it refers to tin dioxide (S
r102), zinc oxide (ZnC1), -g4 oxide (C
u20), -manganese oxide (MnO), nickel oxide (
Nip) and tricobalt tetroxide (C0304), each singly or a composite of two or more of them in any combination. Among these, 5n02. ZnO is especially suitable for (2).

The thickness of the thin layer of these metal monohydrides is preferably in the range of 0.01 to 1.0 μm for the same reason as in the case of the water repellent layer.

In the present invention, in order to independently impregnate the thin layer of the metal oxide having the above-mentioned oxygen adsorption ability, it is necessary to add the hydrophobic layer and the thin layer of the metal oxide having the oxygen adsorption ability to the electrode body. In order to laminate the layers in this order on the side surface, the following method is applied.

The first method for the former is to place a
This is a method in which a metal oxide having oxygen adsorption ability is deposited using a direct vapor deposition method or a sputtering method to form a thin film of a predetermined thickness.

The second method is to first deposit a metal oxide with oxygen adsorption ability on one side of a flexible porous membrane having micropores with a pore diameter of 01 μm or less using a vapor deposition method or a sanding method. A thin layer of metal oxide is formed to form a two-layer composite thin film, and then the other side of the composite thin film, i.e.
This is a method in which the other surface of the porous membrane is pressed onto the gas side surface of the electrode body under a predetermined pressure to integrate it.

The first method for the latter is to apply on the gas side surface of the electrode body,
By vapor deposition or sputtering, a material capable of forming a water repellent layer is first directly deposited to a predetermined thickness to form a water repellent layer, and then a layer with oxygen adsorption capacity is added on top of the water repellent layer. This method involves depositing a metal oxide having a predetermined thickness to form a thin layer of the metal oxide.

The second method is to first form a drainage layer on one side of a flexible porous membrane having micropores with a pore diameter of 0.1 μm or less by vapor deposition or sputtering, and then form a drainage layer on the water-repellent layer. A thin layer of a metal oxide having oxygen adsorption ability is formed on the surface of the porous membrane, a water-repellent layer, and a thin layer of the metal oxide to form a composite thin film. This is a method in which the other surface is crimped with the gas-side surface number of the electrode body at a predetermined pressure to integrate the electrode body.

Furthermore, the material of the porous membrane used in each of the second methods does not matter as long as it has micropores with a pore diameter of 01 μm or less. For example, porous fluororesin membranes (trade name, Fluoropore; manufactured by Sumitomo Rinko Co., Ltd.), porous polycarbonate membranes (trade name, 2Z Kuripore; manufactured by Nikulipore Corporation), porous cellulose ester membranes ( Flexible 1, such as (trade name, Millipore Ame/Plan filter; made by Milliboa Kobo Rayon), porous 1 raw polypropylene 1 quality (trade name, Celguard; made by Celanese Plastics)
Raw porous membranes can be mentioned. In a porous membrane, when the pore diameter exceeds 0.1 μm, when a metal oxide thin film having oxygen adsorption ability, a water repellent layer, and a metal oxide thin film having oxygen adsorption ability are formed on the porous membrane, the obtained The resulting composite thin film is prone to pinholes and cracks, causing the thin film to lose its function and its mechanical strength to decrease, making it more susceptible to breakage.

The air electrode of the present invention thus manufactured is incorporated into a battery according to a conventional method. In this case, the intermittent divisor makes it possible to supply an instantaneous large current by not only the electrochemical reduction of oxygen gas but also the chemical reduction of the electrode components themselves, so that the oxidation-reduction equilibrium potential of oxygen is ) is also 0.4
It is preferable to integrally attach a porous layer containing at least a metal, oxide, or hydroxide whose oxidation state changes by forming a base within the range of v to the electrolyte side of the electrode body. This porous layer is oxidized by oxygen scum by local cell action during discharge under a light load or when the circuit is opened, and returns to the original oxidized state.

Constituent materials for such a porous layer include Ag2o, M
Examples include nO2, co2o3, PbO2, various perovskite type oxides, and spinel type oxides.

On the other hand, the air electrode is not only incorporated into a battery in the form of a plate, but may also be incorporated into a cylindrical battery, in which case the plate-shaped air electrode may be wound to form a cylinder. In such cases, in order to provide mechanical stability without damaging the air electrode during the winding process, a porous fluororesin film is added to the gas side surface of the thin layer of metal oxide that has oxygen adsorption ability. It is preferable to integrally attach a porous thin film such as a porous polycarbonate film, a porous cellulose ester model, or a porous polypropylene film.

[Embodiments of the invention]

Examples 1 to 6 A Raney nickel plate (thickness: 200 trn) with an average pore diameter of 5 μm and a porosity of 80 was used as the electrode body. The O sputtering conditions were as follows: This was set in a sputtering equipment aK, and a thin layer of the above metal oxide was directly formed on one side of the Raney nickel plate using various metal oxides with oxygen adsorption ability as targets.
Argon gas pressure 2X10 TOrr.

The high frequency deer was 100W. The thickness of each metal oxide thin film was 0.2 μm.

Next, these were immersed in a two-line palladium chloride solution and cathodically polarized to give a polarization of about 0.5μ, including inside the pores of Raney nickel.
The pneumatic metal J= of the present invention is prepared by depositing palladium with a thickness of m.
It's shi.

Examples 7 to 12 Thickness 5 with uniform distribution of micropores with an average pore diameter of 0.03 μm
μm porous polycarbonate membrane (product name: Ni.

A thin layer of a metal oxide having oxygen adsorption ability was formed on one side of the model under the same conditions as in Examples 1 to 6. A thin layer of 0.2 μm was formed. The other side of this porous membrane was then pressure-bonded to one side of a Raney nickel plate (thickness: 200 μm) with an average pore diameter of 5 μm and a porosity of 80%.

This was immersed in a divalent palladium chloride solution and cathodically polarized to precipitate approximately 0.2 μm of palladium, including inside the pores of the Raney nickel plate, to form the air electrode of the present invention.Examples 13 to 18 Average pore diameter: 5 μm A Raney nickel plate (thickness: 200 μm) with a porosity of 80 mm was used as the electrode body. Fluoroethylene propylene (FEP) was deposited on one side of this Raney nickel plate under sputtering conditions of argon gas pressure 1X10 Torr and high frequency em power 200 W. Thickness 0.2μ
A water-repellent layer of FEP 5 was formed.

Next, this is set in a sputtering device, and the FE is
A thin layer of the above metal oxide was formed directly on the Pi aqueous layer. The sputtering conditions are argon gas pressure 2×10 Tor
r, high frequency 9 power 100W. Metallization (the thickness of the thin film on the snout was 0.1 μm in all cases).

Next, these were immersed in a dipolypalladium chloride solution and cathodically polarized to give a polarization of about 0.5μ, including inside the pores of Raney nickel.
Palladium was deposited to a thickness of m to obtain an air electrode of the present invention.

Examples 19 to 24 Thickness of 5 μm with uniform distribution of micropores with an average pore diameter of 003 μm
One side of a porous polycarbonate membrane (trade name: Nucleipore, manufactured by Nucleipore Corporation) with a temperature of K, argon gas pressure I x 102 Torr, high frequency power 20
Under 'OW' sputtering conditions, fluoroethylene propylene (
PEP) was applied to form a water-repellent first layer with a thickness of 0.2 μm.

Next, a thin layer of a metal oxide having oxygen adsorption ability was formed on the FEP water-repellent layer in the same manner as in Examples 13 to 18. A thin layer of 0.1 am was formed.

The porous polycarbonate vent side of the obtained composite thin film was integrally bonded to one side of Raney nickel (thickness: 200 μm) having an average pore diameter of 5 μm and a porosity of 80%.

Next, this was immersed in a 2% palladium chloride solution and cathodically polarized to deposit palladium of about 0.05 μm including inside the pores of the Raney nickel plate, which was used as the air electrode of the present invention.

Comparative Examples 1 to 4 Mixed gas (oxygen 50%, argon 5%
An air electrode was produced by forming a thin layer (0.2 μm) of various metal oxides having oxygen adsorption capacity in the same manner as in Examples 1 to 4, except that 0.0-chi) was used.

Comparative Examples 5 to 8 Mixed gas (oxygen 50%, argon,
Thin layers of metal oxides having various oxygen adsorption capacities (0,2
0 Comparative Examples 9 to 1 in which air electrodes were prepared by forming μIη)
2 Mixed gas (50 parts oxygen, 5 parts argon) in the sputtering reaction tank
Thin layers of metal oxides having various oxygen adsorption capacities (0.1 μm
) and prepare an air electrode.Comparative Examples 13 to 16 A mixed gas (50% oxygen, 5% argon) was placed in the sputtering reaction tank.
Thin layers of metal oxides having various oxygen adsorption capacities (0.1 μm
) was formed to produce an air electrode.

Comparative Example 17 Activated carbon powder was suspended in an aqueous solution of palladium chloride, and then reduced with formalin to obtain palladium-attached activated carbon powder. Next, this powder was waterproofed with 10 to 15% polytetrafluoroethylene resin, mixed with PTFE powder as a binder, and rolled into a sheet. Press this sheet onto Ninokernent to make the thickness 0.
．． It was made into a 6 mm 4-pole main body. Next, P T was added to the artificial graphite powder.
After mixing the FE dispersion, it was thermally treated to obtain waterproof graphite powder, which was then mixed with hexagonal adhesive, PTFE powder, and rolled. The obtained sheet was crimped to the above-mentioned unipolar body to make an air electrode with a thickness of 1.6 rsm.
μm) was pressed onto one side of a Raney nickel plate (thickness 200 μm) with an average pore diameter of 5 μm and a porosity of 80%, and then the whole was cathodically polarized in a palladium dichloride solution to form a 0.5 μm layer including the inside of the pores of the Raney nickel plate. Palladium was deposited to form an air electrode.

Comparative Example 19 A water vapor absorption layer of calcium chloride/ram was attached to the air side of the air electrode manufactured in Comparative Example 17.

Comparative Example A polycarbonate material having a thickness of 5 μm and having pores with an average pore diameter of 0.15 μm distributed thereon was coated on one side of a porous raw polycarbonate 14 (trade name: Nykrybore, manufactured by Nykrybore Corporation) in the same manner as in Examples 1 to 6. A thin film of ZNO having a thickness of 0.2 μm was formed, and the other film was pressure-bonded to one side of a Raney nickel plate having an average pore diameter of 5 μm and a porosity of 80.

All pieces were immersed in dichloropalladium solution and cathodically polarized.
Approximately 0.5 μm of palladium was deposited on the Raney nickel plate, including inside the pores, and an air electrode was made. Example 21: A porous polycarbonate membrane with an average pore diameter of 0.03 μm was used, and the thickness of the ZnO thin film was 0. Four air surfaces were manufactured in the same manner as in the comparative example section, except that the thickness was .005 μm.

Comparative Example n An air electrode was manufactured in the same manner as Comparative Example 21, except that the thickness of the Zno thin film was 2.0 μm.

Comparative example Example 11 was applied to one side of a 5 μm thick porous I raw polycarbonate membrane (trade name: Nykuribore, manufactured by Nykuribore Corporation) in which pores with an average pore diameter of 015 μm are distributed.
3 to 18, first, PEP i with a thickness of 02 μm
An aqueous layer was formed by sputtering, and then a 0.1 μm thick ZnO thin layer was formed thereon by sputtering in the same manner as in Examples 13-18. The porous polycarbonate membrane side of the obtained composite thin film was pressed onto one side of a Raney nickel plate (thickness: 200 μm) having an average pore diameter of 51 trn and a porosity of 80 strips to be integrated. This was immersed in a dichloropalladium chloride solution and cathodically polarized to deposit palladium of about 0.5 μm, including inside the pores of the Raney nickel plate, to form an air electrode.

Comparative example part Comparative example n
An air electrode was manufactured in the same manner.

Comparative example part・F'EP Water-stirring layer thickness is 2.0 μm, ZnQ
An air electrode was manufactured in the same manner as in the comparative example except that the thickness of the O thin layer was 10 μm.

Comparative Example Section A composite layer consisting of the Raney nickel plates of Examples 13 to 18 and the FEP water repellent state was immersed in a dichloropalladium solution and 5 tons of sea urchin was added. 5μm of palladium was deposited and air was used for the first time.

Comparative Example 27 Porous polycarbonate membrane and FDP of Examples 19 to 24
The porous polycarbonate film side of the composite thin film comprising the water-repellent layer was pressed onto one side of a Raney nickel plate having an average pore diameter of 5 μm and a porosity of 80%. This was immersed in a didominant palladium chloride solution to deposit palladium of about 0.5 .mu.m including inside the pores of the Raney nickel plate during cathodic polarization 1 to form an air' electrode.

Using the above 51 air electrodes, an air zinc acid oil was assembled using gelled zinc amalgamated with mercury at a weight ratio of 3 as the counter electrode, potassium hydroxide as the electrolyte, and polyamide nonwoven fabric as the separator.

After leaving these 51 batteries in air at 5°C for 16 hours, they were heated for several minutes at each current of 1. It was measured. In addition, these batteries were stored in an atmosphere with a relative humidity of 45° C. and 190° C., and leakage of the electrolyte was observed.

After reconditioning and storage, conduct a discharge test similar to the above, and calculate the ratio of the current value to the initial current value (relationship).
was calculated. This calculated value represents the degree of deterioration of the air electrode of each battery and can be called the discharge characteristic maintenance rate. The higher the value, the lower the deterioration.

Regarding the thin film attached to each box, the oxygen gas permeation rate was measured by the isobaric method using a gas chromatograph as the gas detection means, and the water vapor permeation rate was measured by a method according to JIS Z0208 (cup method). The ratio of (calculated)

The above results are summarized in the table.

The following margins [Effects of the Invention] As is clear from the above results, the air electrode of the present invention is thin as a whole and does not allow water vapor or carbon dioxide gas in the air to enter the electrode body, so that it can be used for a long period of time. Since it enables one load discharge/llS and also has a negative impact on storage performance, both industrial values are low.

Note that the performance evaluation of the air electrode in the above example was carried out using hydroxide IJ"7M as the electrolyte, but other electrolytes such as ammonium chloride, sodium hydroxide,
It goes without saying that similar effects can be obtained by using an electrolytic solution in which rubidium hydroxide, lithium hydroxide, cesium hydroxide, etc. are mixed into these solutions. Furthermore, the air electrode according to the method of the present invention can also be used in air-iron ponds.

Agent Patent Attorney Noriyuki Chika (1 other person)

Claims (9)

[Claims] (1) A metal oxide with oxygen adsorption ability is applied by vapor deposition or sputtering to the gas side surface of a porous electrode body that has electrochemical reduction ability for oxygen gas and also has a current collector function. 1. A method for producing an air electrode, comprising depositing the metal oxide as a sputtering source or vapor deposition source to form a thin film of the metal oxide. (2) The method for manufacturing an air electrode according to claim 1, wherein in the vapor deposition method or sputtering method, the reaction tank gas is an inert gas containing or not containing 10 or less oxygen. (3) The method for manufacturing an air electrode according to claim 1, wherein the electrode body has pores having a pore diameter of 0.1 to 10 μm. (4) The method for producing an air electrode according to claim 1 or 2, wherein the thin film of the metal oxide having oxygen adsorption ability has a thickness of 0.01 to 1.0 μm. (5) A metal oxide having oxygen adsorption ability is deposited on one surface of a porous film having micropores with a pore diameter of o, iμm or less using a vapor deposition method or a sputtering method as a sputtering source or a vapor deposition source. A thin layer of oxide is formed, and then the other surface of the porous membrane is formed on the gas side surface of a porous electrode body that has an electrochemical reducing ability for oxygen gas and also has a current collector function. A method of manufacturing an air electrode characterized by crimping and integrating the air electrode with the electrode. (6) The method for producing an air electrode according to claim 5, wherein in the vapor deposition method or sputtering method, the reaction tank gas is an inert gas containing or not containing 10 or less oxygen. (7) The method for manufacturing an air electrode according to claim 5, wherein the electrode body has pores having a pore diameter of 0.1 to 10 μm. (8) The method for producing an air electrode according to claim 5 or 6, wherein the thin layer has a thickness of 0.01 to 1.0 μm. (9) Forming a water-repellent layer by vapor deposition or sputtering on the gas side surface of the porous electrode body, which has a chemical reduction ability for oxygen gas and also has an aggregate function;
Further, on the water repellent layer, a metal oxide having oxygen adsorption ability is deposited as a sputtering source or vapor deposition source by a vapor deposition method or a sputtering method to form a thin layer of the metal oxide. Method of manufacturing electrodes. α0 In the vapor deposition method or the sputtering method, the reaction tank gas is an inert gas containing or not containing 10% or less of oxygen. 11. The method for producing an air electrode according to claim 9 or 10, wherein the thin layer of the metal oxide has a thickness of 0.001 to 1.0 μm. 10. The method for producing an air electrode according to claim 9, wherein the water repellent layer has a thickness of 0.01 to 1.0 μm. 03) The method for manufacturing an air electrode according to claim 9, wherein the electrode body has pores having a pore diameter of 0.1 to 10 μm. 114) A water repellent layer is formed on one side of a porous membrane having micropores with a pore diameter of 0.1 μm or less by a vapor deposition method or a sputtering method, and an oxygen adsorption ability is further formed on the water repellent layer by a vapor deposition method or a sputtering method. A thin layer of the metal oxide is deposited as a sputtering or vapor deposition source, and the other side of the porous membrane is then electrochemically reduced to oxygen gas. A method for producing an air electrode, characterized in that the air electrode is pressure-bonded to the gas side surface of a porous electrode body that also serves as a current collector. a5) In the vapor deposition method or sputtering method, the reaction tank gas is oxygen. The method for manufacturing an air electrode according to claim 14, characterized in that the inert gas contains or does not contain 10 or less. a6) The thickness of the thin layer of the metal oxide is 0.01 ~1.0
The method for manufacturing an air electrode according to claim 14 or 15, wherein the air electrode is μm. 15. The method of manufacturing an air electrode according to claim 14, wherein the water repellent layer has a thickness of 0.01 to 1.0 μm. The method for producing an air electrode according to claim 14, wherein the electrode body has pores having a pore diameter of 0.1 to 10 μm.