JPS58225574A - Air electrode and its production method - Google Patents

Abstract

PURPOSE:To obtain a thin air electrode excellent in the storage performance by preventing the water vapor or carbon dioxide in the air from infiltrating into the electrode proper so as to enable an over-load discharge for a long time. CONSTITUTION:Metal oxide with a rutile type crystal structure is deposited by an evaporation method or a spattering method on the gas side surface of a porous electrode proper having the electrochemical reduction capability against oxygen gas and current collector function concurrently to form the thin film of said metal oxide, or metal oxide with a rutile type crystal structure is deposited by the evaporation method or spattering method on one side surface of a porous film having fine holes with a bore diameter of 0.1mum or less to form the thin film of said metal oxide, next the other side surface of said porous film is stuck by pressure in one body to the gas side surface of the porous electrode proper having the electrochemical reduction capability against oxygen gas and current collector function concurrently. According to this constitution, the whole electrode is made thin and the water vapor or carbon dioxide in the air is prevented from infiltrating into the electrode proper, thus enabling an over-load discharge for a long time.

Description

【発明の詳細な説明】 〔発明の技術分野〕 本発明は、水素／酸素燃料電池、金属／空気型１池、酸
素センサ用の空気電極とその製造方法に関し、更に詐し
くは、薄くても長時間に亘ｐ重負荷放電が可能で、保存
性能にも優れた空気電極と千の製造方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an air electrode for a hydrogen/oxygen fuel cell, a metal/air type one cell, and an oxygen sensor, and a method for manufacturing the same. This invention relates to an air electrode that is capable of long-term heavy load discharge and has excellent storage performance, and a thousand manufacturing methods.

〔発明の技術的背景とその問題点〕[Technical background of the invention and its problems]

従来から、各種の燃料電池、空気／亜鉛電池をはじめと
する空気金属電池やガルバニ型の酸素センサなどの空気
電極には、ガス拡散電極が用いられてきている。このガ
ス拡散電極としては初期には均一孔径分布を有する浮型
の多孔質電極が用いられてきたが、最近では、酸素ガス
に対する電気化学的還元能（酸素をイオン化する）を有
しかつ集電体機能も併有する多孔質の電極本体と、該′
電極本体のガス側表面に一体的に添着される薄膜状の撥
水性層とから成る２Ｎ構造の電極が多用巧れている。Conventionally, gas diffusion electrodes have been used as air electrodes in various fuel cells, air metal batteries including air/zinc batteries, and galvanic oxygen sensors. Initially, a floating porous electrode with a uniform pore size distribution was used as this gas diffusion electrode, but recently it has been used as a floating porous electrode with an electrochemical reduction ability (ionizing oxygen) for oxygen gas and a current collecting electrode. A porous electrode body that also has body functions, and
Electrodes with a 2N structure consisting of a thin film-like water-repellent layer integrally attached to the gas-side surface of the electrode body are often used.

この場合、電極本体は主として、酸素ガス還元過電圧の
低いニッケルタングステン酸；パラジウム・コバルトで
破覆された炭化タングステン；ニッケル；銀；白金；パ
ラジウムなどを活性良粉末のような導電性粉末に担持せ
しめて成る粉末にポリテトラフロロエチレンのような結
着剤を添加した後、これを金属多孔質体、カーボン多孔
質体、カーボン繊維の不織布などと一体化したものが用
いられている。In this case, the electrode body mainly consists of conductive powder such as active powder supporting nickel-tungstic acid with low oxygen gas reduction overvoltage; tungsten carbide broken down with palladium and cobalt; nickel; silver; platinum; palladium, etc. A binder such as polytetrafluoroethylene is added to a powder made of the above powder, and then this is integrated with a porous metal body, a porous carbon body, a nonwoven fabric of carbon fiber, etc.

また、電極本体のガス側表面に添着される撥水性層とし
ては主にポリテトラフロロエチレン、ポリテトラフロロ
エチレン−ヘキサフロロプロピレン共重合体、ポリエチ
レン−テトラフロロエチレン共重合体などのフッ素樹脂
、又はポリプロビレ本などの樹脂から構成される薄膜で
あって、例えば、粒径０．２〜４０μｍのこれら樹脂粉
末の焼結体；これら樹脂の繊維を加熱処理して不織布化
した紙状のもの；同じく繊維布状のもの；これら樹脂の
粉末０一部を７″化黒鉛で置きかえたもの；２れら　　
　セの微粉末を増孔剤・潤滑油などと共にロール加圧し
てから加熱処理したフィルム状のもの、もしくＦｉロー
ル加圧後加熱処理をしないフィルム状のもの；などの微
細孔を分布する多孔性の薄膜である。The water-repellent layer attached to the gas side surface of the electrode body is mainly made of fluororesin such as polytetrafluoroethylene, polytetrafluoroethylene-hexafluoropropylene copolymer, polyethylene-tetrafluoroethylene copolymer, 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 material made by heating the fibers of these resins and making them into a nonwoven fabric; Fiber cloth-like; Part of these resin powders replaced with 7"graphite; 2.
A film with a distribution of fine pores, such as a film made by applying a heat treatment after pressing a fine powder of Fi with a pore-forming agent, lubricating oil, etc., or a film that is not heat-treated after being pressed by a fi roll. It is a thin film of sex.

しかしながら“；上記した従来構造の空気電極において
、電極本体のガス側表面に添着されている撥水性ＮＩは
、電解液に対しては不透過性であるが、空気又は空気中
の水蒸気に対しては不透過性で杜ない。However, in the air electrode of the conventional structure described above, the water-repellent NI attached to the gas side surface of the electrode body is impermeable to the electrolyte, but is impermeable to air or water vapor in the air. is opaque and unmistakable.

そのため、例えば空気中の水蒸気が撥水性層を通過して
電極本体に侵入しその結果電解液を稀釈したり、または
逆に電解液中の水が水蒸気として撥水性層から放散して
しまい電解液を濃縮することがある。この結果、電解液
の濃度が変動してしまい安定した放電を長時間に亘り維
持することができなくなるという事態が生ずる。Therefore, for example, water vapor in the air may pass through the water-repellent layer and enter the electrode body, diluting the electrolyte, or conversely, water in the electrolyte may evaporate from the water-repellent layer as water vapor, causing the electrolyte to dissolve. may be concentrated. As a result, the concentration of the electrolytic solution fluctuates, resulting in a situation where stable discharge cannot be maintained for a long time.

）気中の炭酸ガスが撥水性ｅｔ通過して電極本体内に侵
入して活性層に吸着した場合、その部位の酸素ガスに対
する電気化学的還元能が低下して重負荷放電が阻害され
る。また、電解液がアルカリ電解液の場合には、電解液
の変質、濃度の低下又は陰極が亜鉛のときには該亜鉛陰
極の不働態化などの現象を引き起こす。更には、活性＃
（電極本体の多孔質部分）で、炭酸塩を生成して孔を閉
塞し、電気化学的還元が行なわれる領域を減少させるの
で重負荷放電が阻害される。) If carbon dioxide gas in the air passes through the water repellent et, enters the electrode body and is adsorbed on 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, active #
(in the porous part of the electrode body), carbonates are formed to block the pores and reduce the area where electrochemical reduction can take place, thus inhibiting heavy load discharge.

このようなことは、製造した電池を長期間保存しておく
場合又は、長期間使用する場合、電池の性能が設計規準
から低下するといり事態を招く。This may cause a situation in which the performance of the battery deteriorates from the design standard when the manufactured battery is stored or used for a long period of time.

このため、を気電極の撥水性層のガス側（９気側）に更
に塩化カルシウムのような水分吸収剤又はアルカリ土類
金属の水酸化物のような炭酸ガス吸収剤の層金設けた構
造の電池が提案されている。For this reason, a layer of a moisture absorbent such as calcium chloride or a carbon dioxide absorbent such as alkaline earth metal hydroxide is provided on the gas side (9 gas side) of the water-repellent layer of the gas electrode. batteries have been proposed.

これは、上記したような不都合な事態をある程夏防止す
ることはできるが、ある時間経過後、これら吸収剤が飽
和状態に達しその吸収能力を喪失すれば、その効果も消
滅するのでなんら本質的な解決策ではあり得ない。This can prevent the above-mentioned inconveniences to some extent in the summer, but if these absorbents reach a saturated state and lose their absorption capacity after a certain period of time, the effect disappears, so there is no real benefit. It cannot be a simple solution.

〔発明の目的〕 本発明は、従来構造の以上のような欠点を解消し、空気
中の水蒸気又祉炭酸ガスが電極本体内に侵入せず、した
がって長期に亘る重負荷放電が可能で保存性能にも優れ
た薄い空気電極とその製造方法の提供を目的とする。[Object of the Invention] The present invention eliminates the above-mentioned drawbacks 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 the present invention is to provide an excellent thin air electrode and a method for manufacturing the same.

〔発明の概要〕[Summary of the invention]

本発明の空気電極は、酸素ガスに対する電気化学的還元
能を有し、かつ集電体機能も併有する多孔質の電極本体
と；該電極本体のガス側表面に直接又は多孔性膜を介し
て一体的に添着されたルチル型結晶構造の金属酸化物の
薄膜とから成ることを特徴とする構造であり、その製造
方法は、酸素ガスに対する電気化学的還元能を有し、か
つ、集電体機能も併有する多孔質の電極本体のガス側表
面に、蒸着法又はスパッタリング法で、ルチル型結晶構
造の金属酸化物を被着せしめて該金属酸化物の薄膜を形
成するものであり、また、他の態様としては、孔径０．
１μｍ　以下の微細孔を有する多孔性膜の一方の面に、
蒸着法又はスパッタリング法でルチル型結晶構造の金属
酸化物を被着せしめて該金属酸化物の薄層を形成し、つ
いで、該多孔性膜の他方の面を、酸素ガスに対する電気
化学的還元能を有し、かつ、集電体機能も併有する多孔
質の電極本体のガス側表面に圧着して一体化することを
特徴とするものである。The air electrode of the present invention has a porous electrode body that has an electrochemical reduction ability for oxygen gas and also has a current collector function; This structure is characterized by consisting of a thin film of a metal oxide with a rutile crystal structure attached integrally with the metal oxide, and its manufacturing method is characterized by having an electrochemical reduction ability for oxygen gas and a current collector. A metal oxide having a rutile type crystal structure is deposited on the gas side surface of a porous electrode body that also has a function by a vapor deposition method or a sputtering method to form a thin film of the metal oxide, and In another embodiment, the pore size is 0.
On one side of a porous membrane having micropores of 1 μm or less,
A metal oxide having a rutile crystal structure is deposited by vapor deposition or sputtering to form a thin layer of the metal oxide, and then the other side of the porous film is electrochemically reduced to oxygen gas. It is characterized by being pressure-bonded and integrated with the gas-side surface of a porous electrode body that also has a current collector function.

本発明の空気電極に用いる電極本体は、酸素ガスを電気
化学的に還元する（酸素ガスをイオン化する）活性能を
有し、かつ、導電性の多孔質体である。具体的には、前
述したようなものの外に、／ＩＪ１フィルター、ラネー
ニッケル、銀又はニッケル　　　゛の焼結体、各種の発
泡メタル、ニッケルメッキしたステンレススチール細線
の圧縮体、及びこれに金、パラジウム、銀などをメッキ
して成る金属多孔質体などをあげることができる。なお
、このとき、電極本体の細孔内で進行する電極反応によ
って生成した酸素ガスの還元生成物イオンを該細孔（反
応領域）から迅速に除去して、例えば５０　ｍＡ／−以
上の重負荷放電を円滑に継続させるために、該電極本体
の細孔の孔径は０．１〜１０μｍ程度の範囲で分布して
いることが好ましい。The electrode body used in the air electrode of the present invention is an electrically conductive porous body that has an active ability to electrochemically reduce oxygen gas (ionize oxygen gas). Specifically, in addition to the above-mentioned items, /IJ1 filters, Raney nickel, sintered bodies of silver or nickel, various foam metals, compressed bodies of nickel-plated fine stainless steel wire, and gold, palladium, Examples include porous metal bodies plated with silver or the like. At this time, the reduction 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), and a heavy load of, for example, 50 mA/- or more is applied. In order to continue the discharge smoothly, the pore diameters of the pores in the electrode body are preferably distributed in a range of about 0.1 to 10 μm.

本発明の空気電極は、上記したような電極本体　　　　
、１のガ洛側表面に、直接又は多孔性膜を介してルチル
型結晶構造の金属酸化物の薄膜を一体的に添着した構造
である。The air electrode of the present invention has an electrode main body as described above.
, 1 has a structure in which a thin film of metal oxide having a rutile type crystal structure is integrally attached to the glass side surface of 1, either directly or via a porous film.

本発明に用いられるルチル型結晶構造の金属酸化物とは
、化学式Ａ　Ｏｘで示され、配位多面体は正８面体でこ
の８面体の稜を共有して１次元的に並んだ集合体が組み
合わさった構造を有するものを指称し、具体的には、二
酸化スズ（ＳｎＯ愈）、二酸化チタン（Ｔｉｌｔ　）　
、二酸化バナジウム（ＶＯ２）、二酸化ニオブ（ＮｂＯ
ｍ）、二酸化クロム（ＣｒＯｚ　）　、二酸化モリブデ
ン（ＭＯＯ２、）、　　二酸化タングステン（ＷＯ２）
、α−二酸化レニウム（α−ＲｅＯｉ　）　、二酸化ル
ビジウム（Ｒｕｂｓ）、二酸化オスミウム（０８０２）
、二階化ロジウム（ＲｈＯｉ　）、二酸化イリジウム（
ＩｒＯｘ）、二酸化白金（Ｐｔ０２）のそれぞれ単独又
は２種以上を任意に組合せた複合体をあげることができ
る。The metal oxide with a rutile crystal structure used in the present invention is represented by the chemical formula AOx, and the coordination polyhedron is a regular octahedron, which is a combination of one-dimensionally arranged aggregates sharing the edges of this octahedron. Specifically, tin dioxide (SnO), titanium dioxide (Tilt)
, vanadium dioxide (VO2), niobium dioxide (NbO
m), chromium dioxide (CrOz), molybdenum dioxide (MOO2, ), tungsten dioxide (WO2)
, α-rhenium dioxide (α-ReOi), rubidium dioxide (Rubs), osmium dioxide (0802)
, rhodium dihydride (RhOi), iridium dioxide (
IrOx), platinum dioxide (Pt02), each singly or a composite of two or more in any combination.

これらのうち、５ｎｏ２．　ＴｉＯ２はとくに有用であ
る。Among these, 5no2. TiO2 is particularly useful.

これらルチル型結晶構造の金属酸化物の薄膜全電極本体
のガス側表面に一体的に添着する次めには、次のような
方法が適用される。The following method is applied to integrally attach a thin film of metal oxide having a rutile type crystal structure to the gas side surface of the entire electrode body.

第１の方法は、電極本体のカス側表面に直接、蒸着法又
はスパッタリング法などの常用の薄膜形成方法で、　ル
チル型結晶構造の金属酸化物を被着せしめて所定の厚み
の薄膜を形成する方法である。The first method is to directly deposit a metal oxide with a rutile crystal structure on the scrap side surface of the electrode body using a commonly used thin film forming method such as vapor deposition or sputtering to form a thin film of a predetermined thickness. It's a method.

第２の方法は、孔径０．１μｍ　以下の微細孔をイアす
る可撓性の多孔性膜の片面に、蒸着法又はスパッタリン
グ法で、まず、ルチル型結晶構造の金属酸化物を被着せ
しめて該金属酸化物の薄層を形成して２＃構造の複合薄
膜を形成し、ついで、この複合薄膜の他方の面、すなわ
ち、多孔性膜の他方の面を電極本体のガス側表面に所定
の圧力で圧力して一体化する方法である。The second method is to first deposit a metal oxide with a rutile crystal structure on one side of a flexible porous film that has micropores with a pore diameter of 0.1 μm or less using a vapor deposition method or a sputtering method. A thin layer of the metal oxide is formed to form a composite thin film with a 2# structure, and then the other side of this composite thin film, that is, the other side of the porous membrane, is placed on the gas side surface of the electrode body in a predetermined position. This is a method of applying pressure to integrate.

第１の方法、第２の方法いずれの場合も、ルチル型結晶
構造の金属酸化物の薄膜形成にあっては、その蒸着源又
はスパッタ源とじてこｎらルチル型結晶構造のｌ金属酸
化物それ自体を適用することができるが、蒸着源又はス
パッタ源として酸素と反応してこれらの金属酸化物を生
成する各種の金属単体を用い、かつ、雰囲気を識素雰四
気にすると、該金属酸化物の薄膜形成速度が高ま９、ま
た、薄層形成の操作も容易になるので好ましい。In both the first method and the second method, when forming a thin film of a metal oxide having a rutile crystal structure, the evaporation source or sputtering source is a metal oxide having a rutile crystal structure. However, if various elemental metals that react with oxygen to produce these metal oxides are used as the evaporation source or sputtering source, and the atmosphere is changed to a nitrogen atmosphere, the metal oxides This method is preferable because it increases the speed of forming a thin film of the product9 and also facilitates the operation of forming a thin layer.

また、形成されるルチル型結晶構造の金属教化物の薄膜
の厚みは、０−０１−１−０　／ｊｍの範囲に調整され
ることが好ましく、０．０１μｍ未満の場合には該薄膜
内にピンホールが増加して空気中の水蒸気、炭酸ガスの
侵入防止効果が低減し、かつ該薄膜の機械的強度も低下
するので破損し易すくなる。他方、１．０μｍ　を超え
ると、電極本体に供給される酸素ガスの透過量が減少し
て電極の重負荷放電が困難となる。In addition, the thickness of the thin film of the metal indoctrination having the rutile type crystal structure to be formed is preferably adjusted to a range of 0-01-1-0/jm, and if it is less than 0.01 μm, the thickness of the thin film formed is within the thin film. As the number of pinholes increases, the effect of preventing intrusion of water vapor and carbon dioxide gas in the air is reduced, and the mechanical strength of the thin film is also reduced, making it more likely to be damaged. On the other hand, if it exceeds 1.0 μm, the amount of permeation of oxygen gas supplied to the electrode body decreases, making it difficult for the electrode to discharge under heavy load.

更に、第２の方法で用いる多孔性膜は、その孔径が０．
１μｍ以下の微細孔を有するものであればその材質は問
わない。例えば、多孔性フッ素樹脂膜（商品名、フロロ
ボア：住友電工■製）、多孔性ポリカーボネート膜（商
品名、ニュクリボア；ニュクリボアコーポレーション製
）、多孔性セルロースエステル膜（商品名、ミリボアメ
ンプランフィルター：ミリボアコーポレーション製）、
多孔性ポリプーロビレン膜（商品名、セルガード；セラ
ニーズ・プラスチック製）などの可撓性の多孔性膜をあ
げることができる。多孔性膜において、その孔径が０．
１μｍを超えると、該多孔性膜にルチル型結晶構造の金
属酸化物の薄膜を形成したとき、その薄膜にピンホール
が発生し易すくなって該薄膜の機能が喪失するとともに
その機械的強度も低下して破損し易すくなる。Furthermore, the porous membrane used in the second method has a pore diameter of 0.
Any material may be used as long as it has micropores of 1 μm or less. For example, porous fluororesin membranes (trade name, Fluorobor; manufactured by Sumitomo Electric Corporation), porous polycarbonate membranes (trade name, Nuclebore; manufactured by Nuclebore Corporation), porous cellulose ester membranes (trade name, Millibore Membrane Filter) : Manufactured by Millibore Corporation),
Examples include flexible porous membranes such as porous polypropylene membranes (trade name: Celguard; manufactured by Celanese Plastics). In a porous membrane, the pore diameter is 0.
If it exceeds 1 μm, when a thin film of a metal oxide with a rutile crystal structure is formed on the porous membrane, pinholes are likely to occur in the thin film, causing the thin film to lose its function and its mechanical strength to deteriorate. becomes weaker and more likely to be damaged.

このようにして製造至れた本発明のを気電極は常法にし
たがって電池に組込まれる。この場合、断続的放電を行
うときに、酸素ガスの電気化学的還元以外［ｗｔ電極成
要素自体の電気化学的還元によって瞬間的な大電流供給
を可能とするため、酸素の酸化還元平衡電位よりも０．
４ｖ以内の範囲で卑な電位によって酸化状態を変化する
金属、酸化物又は水酸化物を少くとも含有する多孔質層
を、電極本体の電解液側に一体的に付設することが好ま
しい。この多孔質層は、軽負荷で放電中又は開路時にあ
ってはローカルセルアクションで酸素ガスによって酸化
され、もとの酸化状態に復帰する。The gas electrode of the present invention thus manufactured is assembled into a battery according to a conventional method. In this case, when performing intermittent discharge, it is possible to supply an instantaneous large current by electrochemical reduction of the oxygen gas [wt] by electrochemical reduction of the electrode component itself, so that the redox equilibrium potential of oxygen Also 0.
It is preferable to integrally attach a porous layer containing at least a metal, oxide, or hydroxide whose oxidation state changes depending on a base potential within a range of 4 V to the electrolyte side of the electrode body. This porous layer is oxidized by oxygen gas by local cell action during discharge under light load or when the circuit is opened, and returns to the original oxidized state.

このような多孔質層の構成材料としては、Ａｇ＊０＋Ｍ
ｎ（ｈ　、　Ｃｏｗ’ｓ　、　Ｐｂ０ｚ　＋各種ぺ・プ
・カイト型酸化　　　セ物、スピネル型酸化物などをあ
げることができる。As a constituent material of such a porous layer, Ag*0+M
Examples include n(h, Cow's, Pb0z + various Pe-P-Kite type oxides, spinel type oxides, etc.).

一方、空気電極は板状で電池に組込まれるだけではなく
、円筒型電池に組込まれる場合もあるが、その場合には
、板状の空気電極を巻回して円筒とすることがある。こ
のようなときには、巻回作業で空気電極を破損させず機
械的安定性を付与するために、ルチル型結晶構造の金属
酸化物の薄膜のガス側表面には、更に、多孔性フッ素樹
脂膜、多孔性ポリカーボネート膜、多孔性セルロースエ
ステル膜、多孔性ボリグロピレン膜などの多孔性薄膜を
一体的に添着しておくことが好ましい。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, It is preferable to integrally attach a porous thin film such as a porous polycarbonate film, a porous cellulose ester film, or a porous polyglopyrene film.

〔発明の実施例〕[Embodiments of the invention]

実施例１〜１３ 平均孔径５μｍ１多孔度８０％のラネーニッケル＃ｉ（
厚み２００ｔｔｍ）を電極本体とした。これを蒸着装置
にセットしてその温度を１５０℃に保持し、装置内の酸
素分圧５　Ｘ　１０−”　Ｔｏｒｒにした。蒸着源は、
Ｓｎ、Ｔｉ　、Ｖ、Ｎｂ、Ｃｒ、Ｍｏ、Ｗ、Ｒｅ、Ｒｕ
、Ｏｓ、Ｒｈ、Ｉｒ。Examples 1 to 13 Raney nickel #i (with average pore size of 5 μm and porosity of 80%)
The electrode body had a thickness of 200 ttm. This was set in a vapor deposition apparatus, and the temperature was maintained at 150°C, and the oxygen partial pressure inside the apparatus was set to 5 x 10-'' Torr.The vapor deposition source was
Sn, Ti, V, Nb, Cr, Mo, W, Re, Ru
, Os, Rh, Ir.

ｐｔ　の１３８類の金属とした。It was a metal of class 138 of PT.

常用の蒸着法によって、ラネーニッケル板の片面に向は
直接上記金属をそれぞれ蒸着せしめた。Each of the above metals was deposited directly on one side of a Raney nickel plate by a conventional vapor deposition method.

いずれの場合もラネーニッケル板の表面には厚み０．２
μｍの金属酸化物が形成された。In either case, the surface of the Raney nickel plate has a thickness of 0.2
.mu.m metal oxide was formed.

ついで、これらを２％塩化パラジウム溶液中に浸漬して
陰分極し、ラネーニッケルの空孔内も含めて約０．５μ
ｍの厚みでパラジウムを析出させ本発明の空気電極とし
た。Next, these were immersed in a 2% palladium chloride solution and cathodically polarized to give a polarization of about 0.5μ, including the inside of the pores of Raney nickel.
Palladium was deposited to a thickness of m to obtain an air electrode of the present invention.

実施例１４〜２６ 実施例１〜１３において、蒸着法に代えてスパッタリン
グ法を適用したことを除いては同様にして本発明の空気
電極を製造し友。スパッタ条件は、アルゴンと酸素の混
合ガス（Ａｒ９０ｖｏ１％、０ｚｌＯｖｏ７％）、圧力
２　Ｘ　１０−”　Ｔｏｒｒ、高周波電力１００Ｗであ
つ九。金属酸化物の薄膜の厚みはいずれも０．２μｍで
あった。Examples 14 to 26 Air electrodes of the present invention were manufactured in the same manner as in Examples 1 to 13, except that a sputtering method was used instead of the vapor deposition method. The sputtering conditions were as follows: a mixed gas of argon and oxygen (90% Ar, 7% OzlOvo), a pressure of 2 x 10-'' Torr, and a high frequency power of 100 W. The thickness of each metal oxide thin film was 0.2 μm.

実施例２７〜３９ 平均孔径０．０３μｍの微細孔を均一に分布する厚み５
μｍの多孔性ポリカーボネート膜（商品名：ニュクリボ
ア、ニュクリボアコーポレーション社製）を蒸着装置に
セットし、１００Ｃに保持し次。装置内を酸素分圧５ｘ
ｌＯＴｏｒｒ　　にし、蒸着源としては実施例１〜１３
て用い次ものを適用して肪族の片面に金属酸化物の薄膜
を形成した。０．２μｍ　の薄膜が形成された。ついで
、この多孔性膜の他方の面を、平均孔径５μｍ、多孔度
８０％のラネーニッケル板（厚み２００μｍ）の片面に
圧着した。Examples 27 to 39 Thickness 5 with uniform distribution of micropores with an average pore diameter of 0.03 μm
A microporous polycarbonate membrane (trade name: Nuclebore, manufactured by Nuclebore Corporation) was set in a vapor deposition apparatus and maintained at 100C. Oxygen partial pressure inside the device 5x
lOTorr, and Examples 1 to 13 were used as the evaporation source.
A thin film of metal oxide was formed on one side of the aliphatic layer using the following method. A thin film of 0.2 μm was formed. Then, the other side of this porous membrane was pressed onto one side of a Raney nickel plate (thickness: 200 μm) having an average pore diameter of 5 μm and a porosity of 80%.

これを２％塩化パラジウム溶液に浸漬して陰分極し、ラ
ネーニッケル板の空孔内も含めて約帆５μｍのパラジウ
ムを析出させ、本発明の空気電極とした。This was immersed in a 2% palladium chloride solution and cathodically polarized to deposit approximately 5 μm of palladium, including inside the pores of the Raney nickel plate, to form the air electrode of the present invention.

実施例４０〜５２ 蒸着法に代えて実施９１Ｊ１４〜２６で適用したスパッ
タ条件によるスパッタリング法を用いたことを除いては
、実施例２７〜３９と同様にして空気電極を製造した。Examples 40 to 52 Air electrodes were manufactured in the same manner as Examples 27 to 39, except that the sputtering method under the sputtering conditions applied in Examples 91J14 to 26 was used instead of the vapor deposition method.

比較例１ 塩化パラジウムの水溶液に活性炭粉末を懸濁した後、ホ
ル１りンで還元してパラジウム付活性炭粉末とした。つ
りで、この粉末ｔｌ−１０〜１５％のポリテトラフロロ
エチレンダイスバージョンで防水処理を施し、更に結着
剤としてＰＴＦＥ粉末を混合した後ロール圧延してシー
トとした。このシートをニッケルネットに圧着して厚み
０．６間の電極本体とした。次に人造黒鉛粉末にＰＴＦ
Ｅデイスノく一ジョンを混合した後、加熱処理して防水
黒鉛粉末とし、これに結着剤としてＰＴＦＥ粉末を混合
してロール圧延した。得られたシートを上記した電極本
体と圧着して厚み１．６ｇの空気電極とした。Comparative Example 1 Activated carbon powder was suspended in an aqueous solution of palladium chloride, and then reduced with phosphorus to obtain palladium-attached activated carbon powder. This powder was waterproofed using a die version of polytetrafluoroethylene with a 10 to 15% tl, and after mixing PTFE powder as a binder, it was rolled into a sheet. This sheet was crimped onto a nickel net to form an electrode body with a thickness of 0.6 mm. Next, PTF is added to the artificial graphite powder.
After mixing E-day technology, heat treatment was performed to obtain waterproof graphite powder, which was mixed with PTFE powder as a binder and rolled. The obtained sheet was crimped to the above-mentioned electrode body to form an air electrode with a thickness of 1.6 g.

比較例２ 酸素ガス選択透過膜であるポリシロキサン膜（厚み５０
μｍ）を、平均孔径５μｍで多孔度８０　ｑｂのラネー
ニッケル板（厚み２００μｍ）の片面に圧着した後、全
体を２％塩化パラジウム溶液中で陰分極してラネーニッ
ケル板の空孔内も含めて０．５μｍのパラジウムを析出
させ空気電極とした。Comparative Example 2 Polysiloxane membrane (thickness 50
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 qb, and then the whole was cathodically polarized in a 2% palladium chloride solution to include the inside of the pores of the Raney nickel plate. Palladium with a thickness of 5 μm was deposited to form an air electrode.

比較例３ 比較例１で製造した空気電極の空気側に塩化カルシウム
の水蒸気吸収Ｉｌを付設した。Comparative Example 3 A water vapor absorption Il made of calcium chloride was attached to the air side of the air electrode manufactured in Comparative Example 1.

比較例４ ・１ 平均孔径０．１５μｍの細孔を分布する厚み５μｍの多
孔性ポリカーボネート膜（商品名；ニュクリボア、ニュ
クリボアコーポレーション社製）の片面に、実施例１〜
１３と同様の方法で厚み０．２μｍのＴｉｅｓの薄膜を
形成し、他方の面を平均孔径５μｍ。Comparative Example 4 ・1 Examples 1 to 1 were applied to one side of a 5 μm thick porous polycarbonate membrane (trade name: Nucribore, manufactured by Nuclebore Corporation) in which pores with an average pore diameter of 0.15 μm were distributed.
A thin film of Ties with a thickness of 0.2 μm was formed using the same method as in No. 13, and the other side had an average pore diameter of 5 μm.

多孔度８０％のラネーニッケル板の片面に圧着した。全
体を２％塩化ノ（ラジウム清液に浸漬して陰分極し、ラ
ネーニッケル板の空孔内も含めて約０．５μｍのパラジ
ウムを析出させ空気電極とした。It was crimped onto one side of a Raney nickel plate with a porosity of 80%. The whole was immersed in a 2% radium chloride solution and cathodically polarized, and about 0.5 μm of palladium was deposited, including inside the pores of the Raney nickel plate, to form an air electrode.

比較例５ 平均孔径０．０３μｍの多孔性ポリカーボネート膜を用
いたこと、ＴｉＯ２の薄膜の厚みが０．００５μｍであ
ったことを除いては、比較例４と同様の方法で空気電極
を製造した。Comparative Example 5 An air electrode was manufactured in the same manner as in Comparative Example 4, except that a porous polycarbonate membrane with an average pore diameter of 0.03 μm was used and the thickness of the TiO2 thin film was 0.005 μm.

比較例６ ＴｉＯｚの薄膜の厚みが２．０μｍ　であったことを除
いては、比較例５と同様にして空気電極を製造したＯ 以上５８個の空気電極を用い、対極を重量比で３′％の
水銀アマルガム化したゲル状亜鉛、電解液を水酸化カリ
ウム、七）くレータをボリアミド不織布として空気−亜
鉛電池を組立てた。Comparative Example 6 Air electrodes were manufactured in the same manner as in Comparative Example 5, except that the thickness of the TiOz thin film was 2.0 μm. Using 58 air electrodes, the counter electrode was 3' in weight ratio. % of mercury amalgamated zinc, potassium hydroxide as the electrolyte, and polyamide nonwoven fabric as the filter, an air-zinc battery was assembled.

これら５８個の電池を２５Ｃの空気中で１６時間放置し
た後、各種の電流で５分間放電し、５分後の端子電圧が
１．０Ｖ以下となるときの＊ｉ１流密度を測足した。ま
た、４５℃、９０％の相対湿朋の雰囲気中にこれら電池
を保存して市、解散の漏洩状態を観察した。After these 58 batteries were left in air at 25 C for 16 hours, they were discharged for 5 minutes with various currents, and the *i1 current density was measured when the terminal voltage became 1.0 V or less after 5 minutes. In addition, these batteries were stored in an atmosphere of 45° C. and 90% relative humidity, and the state of leakage was observed.

更に、保存後の電池につき、上記と同様の放電試験を行
ない、そのときの電流値の初期電流値に対する比（％）
を算出した。この算出値は、各電池の９気電極の劣化状
態の程度を表わし放電特性維持駆といい得るものである
。この値の大きい電極はど劣化が小さいことを表わす。Furthermore, the battery after storage was subjected to a discharge test similar to the above, and the ratio (%) of the current value to the initial current value was calculated.
was calculated. This calculated value represents the degree of deterioration of the 9-electrode of each battery and can be said to be a measure of maintaining discharge characteristics. An electrode with a large value indicates a small degree of deterioration.

また、各電極に添着されている薄膜に関し、酸素ガス透
過速度をガスクロマトゲ２７をガス検出手段とする婢工
法で測足し、水蒸気透過速度をＪＩＳ　Ｚ　０２０８　
　（カップ法）にホした方法で測足し、両者の比を算出
した。In addition, regarding the thin film attached to each electrode, the oxygen gas permeation rate was measured using a crude method using a gas chromatograph 27 as a gas detection means, and the water vapor permeation rate was measured according to JIS Z 0208.
(cup method) and calculated the ratio of the two.

以上の結果を一括して表に示した。The above results are summarized in the table.

〔発明の効果」 以上の結果から明らかなように、本発明の空気電極は全
体が薄く、空気中の水蒸気又は炭酸ガスを電極本体に侵
入させることがなく、そのため、長期に亘る重負荷放電
が可能となり、また保存性能にも優れるのでその工業的
価値は大である。[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 in the air to enter the electrode body, so that heavy load discharge over a long period of time is not possible. It has great industrial value because it has excellent storage performance.

なお、上記実施例の空気電極の性能評価は、電解液とし
て水酸化カリウムを用いて行なったが、他の電解液、例
えば塩化アンモニウムや、水酸化ナトリウムや、水酸化
ルビジウ為、水酸化リチウム、水酸化セシウム等をこれ
ら溶液に混合した電解液を用いても同様の効果が得られ
ることは言うまでもない。また、本発明方法にかかる空
気電極は空気−鉄電池にも用いることができた。Note that although the performance evaluation of the air electrode in the above example was carried out using potassium hydroxide as the electrolyte, other electrolytes such as ammonium chloride, sodium hydroxide, rubidium hydroxide, lithium hydroxide, It goes without saying that similar effects can be obtained by using an electrolytic solution in which cesium hydroxide or the like is mixed with these solutions. Furthermore, the air electrode according to the method of the present invention could also be used in air-iron batteries.

Claims (1)

【特許請求の範囲】 １、　酸禦ガスに対する電気化学的還元能を有し、かつ
、集電体機能も併有する多孔質の電極本体と該電極本体
のガス側表面に、直接又は多孔性膜を介して一体的に添
着されたルチル型結晶構造の金属酸化物の薄膜とから成
ることを特徴とする空気電極。 ２、　該電極本体が、孔径０．１〜１０μｍの細孔を分
布する特許請求の範囲第１項記載の９気電極。 ３、該薄膜の厚みが０．０１〜１．０μｍである特許請
求の範囲第１項記載の空気電極。 ４、　散票カスに対する電気化学的還元能を有し、かつ
、集電体機能も併有する多孔質の電極本体のガス側表面
に、蒸着法又はスパッタリング法で、ルチル型結晶構造
の金属酸化物を被着せしめて該金属酸化物の薄膜を形成
することを特徴とする空気電極の製造方法。 ５、該電極本体が孔径０．１〜１０μｍの細孔を分布す
る特許請求の範囲第４項記載の空気電極の製造方法。 ６、該薄膜の厚みがｏ、ｏｉ〜１．０μｍである特許請
求の範囲第４項記載の空気電極の製造方法。 ７　孔径０．１μｍ以下の微細孔を有する多孔性膜の一
方の面に、蒸着法又はスパッタリング法で、ルチル型結
晶構造の金属酸化物を被着せしめて該金属酸化物の薄層
を形成し、ついで、 該多孔性膜の他方の面を、 酸累ガスに対する電気化学的還元能を有し、かつ、集電
体機能も併有する多孔質の電極本体のガス側表面に圧着
して一体化することを特徴とする空気電極の製造方法。 ＆　該電極本体が、孔径ｏ、１〜１０．ａｍ　　の細孔
を分布する特許請求の範囲第７項記載の空気電極の製造
方法。 ９、該薄膜の厚みが、０．０１〜１．０μｍ　でるる特
許請求の範囲第７項記載の９気！極の製造方法。[Claims] 1. A porous electrode body that has an electrochemical reducing ability for acidic gas and also has a current collector function, and a porous membrane directly or on the gas side surface of the electrode body. An air electrode characterized in that it consists of a thin film of metal oxide having a rutile type crystal structure, which is integrally attached through a thin film of a metal oxide having a rutile type crystal structure. 2. The nine-gas electrode according to claim 1, wherein the electrode body has pores having a pore diameter of 0.1 to 10 μm. 3. The air electrode according to claim 1, wherein the thin film has a thickness of 0.01 to 1.0 μm. 4. A metal oxide with a rutile crystal structure is deposited on the gas side surface of the porous electrode body, which has an electrochemical reduction ability for dust particles and also has a current collector function, by vapor deposition or sputtering. 1. A method for manufacturing an air electrode, comprising depositing a thin film of the metal oxide. 5. The method for manufacturing an air electrode according to claim 4, wherein the electrode body has pores having a pore diameter of 0.1 to 10 μm. 6. The method for manufacturing an air electrode according to claim 4, wherein the thin film has a thickness of o, oi to 1.0 μm. 7. A metal oxide having a rutile crystal structure is deposited on one side of a porous film having micropores with a pore diameter of 0.1 μm or less by a vapor deposition method or a sputtering method to form a thin layer of the metal oxide. Then, the other surface of the porous membrane is pressed and integrated with the gas-side surface of a porous electrode body that has an electrochemical reduction ability for acidic gas and also has a current collector function. A method for manufacturing an air electrode, characterized by: & The electrode body has a pore diameter o of 1 to 10. 8. The method for manufacturing an air electrode according to claim 7, wherein the pores are distributed in the air electrode. 9. The thickness of the thin film is 0.01 to 1.0 μm. How to make poles.