JPH09312157A - Hydrogen storage alloy electrode and manufacture thereof - Google Patents
Hydrogen storage alloy electrode and manufacture thereofInfo
- Publication number
- JPH09312157A JPH09312157A JP8128622A JP12862296A JPH09312157A JP H09312157 A JPH09312157 A JP H09312157A JP 8128622 A JP8128622 A JP 8128622A JP 12862296 A JP12862296 A JP 12862296A JP H09312157 A JPH09312157 A JP H09312157A
- Authority
- JP
- Japan
- Prior art keywords
- hydrogen storage
- storage alloy
- nickel
- alloy
- electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Battery Electrode And Active Subsutance (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、ニッケルー水素蓄
電池の負極などに使用される水素吸蔵合金電極およびそ
の製造方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrogen storage alloy electrode used as a negative electrode of a nickel-hydrogen storage battery and a method for manufacturing the same.
【0002】[0002]
【従来の技術】近年、ポータブル機器、コードレス機器
の発展に伴い、その電源となる電池により一層の高エネ
ルギ−密度が要求されている。この要求を達成するため
に、負極に水素吸蔵合金極を使ったニッケル−水素蓄電
池が注目されている。現在実用化されている水素吸蔵合
金は、Mm−Ni5(Mm:希土類元素の混合物)系の
AB5型合金が中心であり、一部AB2ラーベス相型合金
が用いられている。しかし、機器側からの高容量化への
要望は高く、さらに放電容量の大きい水素吸蔵合金材料
が望まれている。これに対して、近年理論水素吸蔵量が
従来のAB5型合金より大きく、高容量が期待できるZ
rTiMnMNiからなるAB2型ラーベス相合金や、
TiVNi系等の体心立方構造の固溶体型水素吸蔵合金
(以後bcc合金と記す)あるいはMg2NiやMgN
i等のMgNi系合金が注目されている(例えば、特開
平6−228699号公報)。2. Description of the Related Art In recent years, with the development of portable equipment and cordless equipment, a battery as a power source thereof has been required to have higher energy density. In order to achieve this requirement, a nickel-hydrogen storage battery using a hydrogen storage alloy electrode for the negative electrode has been receiving attention. The hydrogen storage alloys currently in practical use are mainly Mm—Ni 5 (Mm: mixture of rare earth elements) type AB 5 type alloys, and AB 2 Laves phase type alloys are partially used. However, there is a strong demand from the equipment side for higher capacity, and a hydrogen storage alloy material with a large discharge capacity is also desired. On the other hand, in recent years, the theoretical hydrogen storage capacity is larger than that of conventional AB 5 type alloys, and high capacity can be expected in Z.
AB 2 type Laves phase alloy composed of rTiMnMNi,
Solid solution type hydrogen storage alloy (hereinafter referred to as bcc alloy) of body-centered cubic structure such as TiVNi system, Mg 2 Ni or MgN
Attention is paid to MgNi-based alloys such as i (for example, Japanese Patent Laid-Open No. 6-228699).
【0003】しかしながら、これらの水素吸蔵合金は、
AB5型合金に比べて合金中のNi量が少ないという点
で以下のような問題がある。すなわち、現在実用化され
ているMm−Ni5系AB5型合金のNi含量は50数w
t%であるのに対して、AB2型ラーベス相合金では3
0数wt%、固溶体型水素吸蔵合金では20wt%以下
である。Niは水素を吸わないBサイト元素であるた
め、AB5型合金のように多量のNiを添加すると、放
電容量が低下する反面、電極活性に優れ、主にKOHか
らなる電解液に対しても安定であるため高率放電特性や
サイクル特性に優れるという利点をもたらす。AB2型
ラーベス相合金やbcc合金は、Ni量が少ないため、
放電容量は高いものの、高率放電特性やサイクル特性が
悪い。MgNi系合金の場合は、Ni量はかなり多い
が、Mgが酸化されやすく、高率放電特性およびサイク
ル特性に課題を有している。However, these hydrogen storage alloys are
There is the following problem in that the amount of Ni in the alloy is smaller than that of the AB 5 type alloy. That is, the Ni content of the Mm-Ni 5 type AB 5 type alloy currently put into practical use is more than 50 w.
t%, whereas it is 3 for the AB 2 type Laves phase alloy
It is 0% by weight, and 20% by weight or less in a solid solution type hydrogen storage alloy. Since Ni is a B-site element that does not absorb hydrogen, when a large amount of Ni is added like an AB 5 type alloy, the discharge capacity is reduced, but on the other hand, the electrode activity is excellent, and even for an electrolyte mainly composed of KOH. Since it is stable, it has an advantage that it is excellent in high rate discharge characteristics and cycle characteristics. AB 2 type Laves phase alloys and bcc alloys have a small amount of Ni,
Although the discharge capacity is high, the high rate discharge characteristics and cycle characteristics are poor. In the case of the MgNi-based alloy, the amount of Ni is considerably large, but Mg is easily oxidized and has problems in high rate discharge characteristics and cycle characteristics.
【0004】これらの対策として、合金表面へのCuや
Niのめっき(特開平2−79369号公報)やニッケ
ル微粉末のメカニカルアロイング(特開昭64−636
6号公報、特開平3−155049号公報)等による合
金表面の被覆、さらにはNi焼成等(特開昭59−14
5752号公報)の方法が提案されてきた。しかし、C
uやNiの添加量の割には水素吸蔵合金の表面に形成さ
れる酸化膜の影響により、高率放電特性やサイクル特性
の改善効果は小さく、多量に添加するとかえって放電容
量の低下を招いていた。As countermeasures against these problems, plating of Cu or Ni on the surface of the alloy (JP-A-2-79369) and mechanical alloying of nickel fine powder (JP-A-64-636).
No. 6, JP-A-3-155049) and the like to coat the alloy surface, and further Ni firing and the like (JP-A-59-14).
No. 5752) has been proposed. But C
Due to the effect of the oxide film formed on the surface of the hydrogen storage alloy, the effect of improving the high rate discharge characteristics and cycle characteristics is small for the added amounts of u and Ni, and the addition of a large amount causes a decrease in the discharge capacity. It was
【0005】[0005]
【発明が解決しようとする課題】本発明は、以上に鑑
み、水素吸蔵合金の表面にNiを有効に付着し、電極活
性と耐食性を向上することにより、高率放電特性および
サイクル特性の改善された水素吸蔵合金電極を提供する
ことを目的とする。In view of the above, the present invention improves the high rate discharge characteristics and cycle characteristics by effectively adhering Ni to the surface of the hydrogen storage alloy and improving the electrode activity and corrosion resistance. Another object is to provide a hydrogen storage alloy electrode.
【0006】[0006]
【課題を解決するための手段】本発明の水素吸蔵合金電
極は、表面に0.15μm以下の電極活性を妨げない程
度に薄い酸化膜を介してニッケル微粉末あるいは多孔質
ニッケル膜が付着している水素吸蔵合金粒子から構成し
たものである。このニッケル微粉末あるいは多孔質ニッ
ケル膜は、単に水素吸蔵合金粒子表面と化学結合を持た
ずに存在しているか、ニッケル粉末あるいは膜の一部が
水素吸蔵合金と合金化した状態で存在している。このニ
ッケル微粉末あるいは多孔質ニッケル膜によって、水素
吸蔵合金電極の高率放電特性およびサイクル特性を改善
することができる。The hydrogen storage alloy electrode of the present invention has a fine nickel powder or a porous nickel film attached to the surface of the electrode through a thin oxide film which does not interfere with the electrode activity of 0.15 μm or less. It is composed of existing hydrogen storage alloy particles. This fine nickel powder or porous nickel film exists simply without having a chemical bond with the surface of the hydrogen storage alloy particles, or a part of the nickel powder or film exists in an alloyed state with the hydrogen storage alloy. . This nickel fine powder or porous nickel film can improve the high rate discharge characteristics and cycle characteristics of the hydrogen storage alloy electrode.
【0007】ニッケルー水素蓄電池の負極用水素吸蔵合
金としては、高容量で電極活性が高く、サイクル寿命に
優れたものが要求される。そして、高容量化に対しては
希土類元素やZrなどのAサイト元素の比率を増やすこ
とが有効であるが、電極活性やサイクル寿命の点ではN
iやCuのようなBサイト元素の添加が効果的である。
この相矛盾した特性を両立させるためには、水素吸蔵合
金の組成だけを検討しても達成は困難である。そこで、
水素吸蔵合金としてはNi量が少なく高容量の組成のも
のを用い、電極活性やサイクル特性は合金表面で対応す
ることが適している。従来、Niめっきや、ニッケル微
粉末をボールミルやメカノフュージョンといった方法で
水素吸蔵合金粒子の表面に付着させることにより、電極
活性に優れるニッケル層を形成する方法が検討されてき
た。A hydrogen storage alloy for a negative electrode of a nickel-hydrogen storage battery is required to have a high capacity, a high electrode activity and an excellent cycle life. Further, it is effective to increase the ratio of the rare earth element and the A site element such as Zr in order to increase the capacity, but in terms of electrode activity and cycle life, N
It is effective to add a B site element such as i or Cu.
It is difficult to achieve both of these contradictory properties even if only the composition of the hydrogen storage alloy is examined. Therefore,
As the hydrogen storage alloy, it is suitable to use a composition with a small amount of Ni and a high capacity, and to cope with the electrode activity and the cycle characteristics on the alloy surface. Conventionally, a method of forming a nickel layer having excellent electrode activity by depositing Ni fine particles or nickel fine powder on the surface of the hydrogen storage alloy particles by a method such as a ball mill or mechanofusion has been studied.
【0008】本発明者らは、ニッケル層による活性化に
ついて種々検討した結果、上記のようにして形成したニ
ッケル層は、水素吸蔵合金表面に存在する厚さ0.15
μmを越す酸化膜上に存在するため、電極活性の付与に
はあまり有効に働かないが、酸化膜が0.15μm以
下、好ましくは0.1μm以下になると、膜の緻密性が
大きく低下し酸化膜が多孔質になるため、Niの添加効
果が顕著に現れることを見いだした。ただし、添加する
ニッケル微粉末の大きさが5μmを越すようなもので
は、多孔質の酸化膜を通して水素吸蔵合金と接触するこ
とができず、特性の改善効果は小さい。As a result of various studies on the activation by the nickel layer, the present inventors found that the nickel layer formed as described above has a thickness of 0.15 existing on the surface of the hydrogen storage alloy.
Since it exists on the oxide film exceeding μm, it does not work very effectively for imparting the electrode activity, but when the oxide film becomes 0.15 μm or less, preferably 0.1 μm or less, the denseness of the film largely decreases and the oxidation It was found that the effect of adding Ni is remarkable because the film becomes porous. However, if the size of the added nickel fine powder exceeds 5 μm, it cannot contact the hydrogen storage alloy through the porous oxide film, and the effect of improving the characteristics is small.
【0009】[0009]
【発明の実施の形態】本発明の水素吸蔵合金電極を構成
する水素吸蔵合金粒子表面に、厚さ0.15μm以下の
酸化膜を介してニッケル微粉末あるいは多孔質ニッケル
膜を付着させる具体的手段を以下に説明する。まず、第
一の方法は、水素吸蔵合金粒子を、高温の水素ガス雰囲
気で還元処理するか、フッ化水素酸水溶液でエッチング
することにより、表面の酸化物の少なくとも一部を除去
する。具体的には、酸化膜を0.15μm以下、好まし
くは0.1μm以下にまで薄くする。次に、不活性ガス
中で水素吸蔵合金粒子の表面にニッケル微粉末をメカノ
フュージョン、ボールミルあるいは気流衝撃法などの機
械的方法により付着させる方法である。ここに用いるニ
ッケル微粒子としては、カーボニルニッケル、ラネーニ
ッケルあるいはNiと強アルカリ水溶液に溶ける元素か
らなるNi−X(XはAl、Sn、Mg、CaおよびZ
nの群より選ばれる少なくとも1種)で表されるニッケ
ル合金微粒子を水アトマイズ法、ガスアトマイズ法、ま
たはメカニカルアロイ法で作製した後、高温の強アルカ
リ水溶液中に浸漬し、ニッケル合金微粒子中の溶出成分
を除去して作製したものが用いられる。BEST MODE FOR CARRYING OUT THE INVENTION Specific means for attaching fine nickel powder or porous nickel film to the surface of hydrogen storage alloy particles constituting the hydrogen storage alloy electrode of the present invention through an oxide film having a thickness of 0.15 μm or less. Will be described below. First, the first method removes at least a part of the oxide on the surface by subjecting the hydrogen storage alloy particles to reduction treatment in a high temperature hydrogen gas atmosphere or etching with a hydrofluoric acid aqueous solution. Specifically, the oxide film is thinned to 0.15 μm or less, preferably 0.1 μm or less. Next, it is a method in which fine nickel powder is adhered to the surface of the hydrogen storage alloy particles in an inert gas by a mechanical method such as mechanofusion, a ball mill or an air flow impact method. The nickel fine particles used here are carbonyl nickel, Raney nickel or Ni-X (X is Al, Sn, Mg, Ca and Z) consisting of Ni and an element soluble in a strong alkaline aqueous solution.
Nickel alloy fine particles represented by (at least one selected from the group of n) are prepared by a water atomizing method, a gas atomizing method, or a mechanical alloying method, and then immersed in a high-temperature strong alkaline aqueous solution to elute in the nickel alloy fine particles. Those produced by removing the components are used.
【0010】第二の方法は、前記と同様に水素吸蔵合金
粒子表面の酸化膜を薄くした後、水素吸蔵合金粒子表面
に無電解めっきにより、多孔質ニッケル膜を付着させる
方法である。第三の方法は、前記と同様に水素吸蔵合金
粒子表面の酸化膜を薄くした後、水素吸蔵合金粒子表面
に無電解めっきにより、前記Ni−X合金膜を形成し、
次に強アルカリ水溶液中に浸漬処理することにより、前
記めっき被膜中の成分Xを溶解して多孔質ニッケル被膜
とする方法である。The second method is a method in which the oxide film on the surface of the hydrogen storage alloy particles is thinned in the same manner as described above, and then the porous nickel film is attached to the surface of the hydrogen storage alloy particles by electroless plating. A third method is to thin the oxide film on the surface of the hydrogen storage alloy particles as described above, and form the Ni-X alloy film by electroless plating on the surface of the hydrogen storage alloy particles,
Next, it is a method of dissolving the component X in the plating film to form a porous nickel film by immersing it in a strong alkaline aqueous solution.
【0011】第四の方法は、前記と同様に水素吸蔵合金
粒子を、高温の水素ガス雰囲気で還元するか、フッ化水
素酸水溶液でエッチングすることにより、酸化膜を0.
15μm以下、好ましくは0.1μm以下にまで薄くし
た後、この水素吸蔵合金粒子を用いて電極を構成し、電
極表面に、電解めっきにより、Ni−Zn、Ni−Sn
およびNi−Coから選ばれるニッケル合金膜を形成
し、次に電極を強アルカリ水溶液中に浸漬処理すること
により、前記めっき被膜中の亜鉛、スズまたはコバルト
を溶解して多孔質ニッケル被膜とする方法である。In the fourth method, as in the above, the hydrogen storage alloy particles are reduced in a high-temperature hydrogen gas atmosphere or etched with a hydrofluoric acid aqueous solution to form an oxide film with an oxygen content of 0.
After thinning to 15 μm or less, preferably 0.1 μm or less, an electrode is formed by using the hydrogen storage alloy particles, and Ni—Zn or Ni—Sn is formed on the electrode surface by electrolytic plating.
And a method of forming a nickel alloy film selected from Ni-Co and then immersing the electrode in a strong alkaline aqueous solution to dissolve zinc, tin or cobalt in the plating film to form a porous nickel film. Is.
【0012】本発明において、水素吸蔵合金粒子を高温
の水素ガス雰囲気で還元するか、あるいはフッ化水素酸
水溶液でエッチングすることにより、合金粒子表面に存
在する酸化膜による被覆効果が大きく低下し、水素吸蔵
合金表面に付着したNiによる電極活性の改善効果が大
きく向上する。ただし、上記のエッチングなどの処理
後、あまり長時間空気中に放置すると、再び酸化膜が形
成されるため、処理後24時間以内にNi処理すること
が好ましい。上記のようにしてニッケル微粉末あるいは
多孔質ニッケル膜を表面に付着した水素吸蔵合金粒子を
真空中で焼結することによって、高率放電特性をさらに
向上することが可能となる。焼結することにより、ニッ
ケル微粉末あるいは多孔質ニッケル膜の一部が水素吸蔵
合金粒子内に拡散し、一部合金化することで電極活性の
大幅な向上が見られ、高率放電特性およびサイクル特性
が改善される。なお、遊星ボールミルやメカノフュージ
ョン法等の機械的な処理によりニッケル微粒子を付着さ
せた場合においても、ごく一部のNiが水素吸蔵合金中
に拡散している。In the present invention, by reducing the hydrogen-absorbing alloy particles in a high-temperature hydrogen gas atmosphere or by etching with a hydrofluoric acid aqueous solution, the effect of covering the oxide particles on the surface of the alloy particles is greatly reduced, The effect of improving the electrode activity by Ni adhering to the surface of the hydrogen storage alloy is greatly improved. However, if left in the air for too long after the above-mentioned etching or the like, an oxide film is formed again. Therefore, it is preferable to perform the Ni treatment within 24 hours after the treatment. As described above, by sintering the hydrogen-absorbing alloy particles having the nickel fine powder or the porous nickel film attached to the surface in a vacuum, it is possible to further improve the high rate discharge characteristics. By sintering, nickel fine powder or a part of the porous nickel film diffuses into the hydrogen-absorbing alloy particles, and a part of them is alloyed to significantly improve the electrode activity. The characteristics are improved. Even when nickel fine particles are attached by a mechanical treatment such as a planetary ball mill or a mechanofusion method, a small amount of Ni diffuses in the hydrogen storage alloy.
【0013】水素吸蔵合金としては、AB2ラーベス相
合金、bcc合金およびMgNi系の高容量の水素吸蔵
合金が特に有効である。なお、水素吸蔵合金表面にニッ
ケル微粉末を機械的に付着させる際は、乳鉢を用いて空
気中で混合させても良いが、不活性雰囲気中でメカノフ
ュージョン法、(遊星)ボールミル法または気流衝撃法
を用いると、水素吸蔵合金表面に拡散層を形成して付着
するため、より好ましい。AB 2 Laves phase alloys, bcc alloys and MgNi-based high capacity hydrogen storage alloys are particularly effective as the hydrogen storage alloys. When mechanically attaching the fine nickel powder to the surface of the hydrogen storage alloy, it may be mixed in air using a mortar, but in an inert atmosphere, the mechanofusion method, (planetary) ball mill method, or airflow impact It is more preferable to use the method since a diffusion layer is formed and adhered on the surface of the hydrogen storage alloy.
【0014】[0014]
【実施例】以下、本発明の実施例を詳しく説明する。 《実施例1》)水素吸蔵合金にはTi0.3V0.5Cr0.1
Ni0.1 のbcc合金を用いた。この合金は、市販のT
i,V,Cr,およびNi金属を原料として、アーク溶
解法によって作製した。次に、この合金に水素を十分吸
蔵させて水素化粉砕し、さらに機械粉砕によって45μ
m以下の水素吸蔵合金粒子を得た。次に、市販の46%
フッ化水素酸水溶液を希釈し、濃度0.5wt%のエッ
チャントを作製し、このエッチャント100ccに対し
て合金粒子10gを加え、室温で10分間緩やかに撹拌
しながらエッチングを行った。この後、水洗、真空乾燥
を行い、水素吸蔵合金粒子を得た。水素吸蔵合金粒子の
表面を直接観察できないため、粉砕前の合金塊を樹脂に
埋め、表面を研磨、脱脂後、24時間放置したものを標
準とし、これを本実施例と同様の条件でフッ化水素酸水
溶液でエッチングしたもの(放置時間2時間)をオージ
ェー分析した。その結果、標準試料では、表面酸化膜の
厚さは0.25μm程度、エッチング後のもので0.1
μmであった。また、エッチング後、24時間放置した
ものでは0.15μmと酸化膜が再び厚くなっているこ
ともわかった。EXAMPLES Examples of the present invention will be described in detail below. << Example 1 >>) Ti 0.3 V 0.5 Cr 0.1 was used for the hydrogen storage alloy.
A bcc alloy of Ni 0.1 was used. This alloy is a commercial T
It was prepared by an arc melting method using i, V, Cr, and Ni metals as raw materials. Next, the alloy was sufficiently occluded with hydrogen and hydrogenated and pulverized.
m or less of hydrogen storage alloy particles were obtained. Next, 46% on the market
The hydrofluoric acid aqueous solution was diluted to prepare an etchant having a concentration of 0.5 wt%, 10 g of alloy particles was added to 100 cc of this etchant, and etching was performed at room temperature for 10 minutes while gently stirring. After that, washing with water and vacuum drying were performed to obtain hydrogen storage alloy particles. Since the surface of the hydrogen storage alloy particles cannot be directly observed, the alloy lump before crushing was embedded in resin, the surface was ground and degreased, and the surface was left for 24 hours as a standard, which was fluorinated under the same conditions as in this example. The product etched with an aqueous solution of hydrofluoric acid (standing time 2 hours) was subjected to Auger analysis. As a result, in the standard sample, the thickness of the surface oxide film is about 0.25 μm, and the thickness after etching is 0.1
μm. It was also found that the oxide film was thickened again to 0.15 μm when left for 24 hours after etching.
【0015】上記水素吸蔵合金粒子90wt%とカーボ
ニルニッケル(インコ・リミテッド日本社製INCOニ
ッケルパウダーType287、平均粒径2.6〜3.
3μm)10wt%を合金のエッチング処理終了後、速
やかに(好ましくは数時間以内)アルゴンガスで充満さ
せた遊星ボールミルで10分間混合し、水素吸蔵合金粒
子上にニッケル微粉末を付着させた。このようにして作
製した水素吸蔵合金粒子に、結着剤としてポリエチレン
粉末を3重量%加え、エタノールでペーストにし、これ
を多孔度95%、大きさ2cm×2cm、厚さ0.6m
mの発泡状ニッケル板に充填し、乾燥後、600kgf
/cm2で加圧し、さらに真空中において130℃で1
時間加熱し、結着剤を溶融させて水素吸蔵合金電極シー
トを作製した。この電極は水素吸蔵合金粒子約1.0g
を含んでいる。これにニッケル製のリード線を溶接して
負極とした。また、水酸化ニッケルを主成分とする正極
合剤を負極と同様の多孔度95%、大きさ2cm×2c
m、厚さ1mmの発泡状ニッケル板に充填し、ニッケル
製のリード線を溶接して正極を作製した。このようにし
て作製した1枚の負極および2枚の正極をそれぞれ厚さ
0.15mmの親水性を付与したポリプロピレン製のセ
パレータで包み、負極を2枚の正極で挟持し、両側から
アクリル樹脂板で締め付けた。これを電槽に入れ、水酸
化カリウム水溶液(密度1.30g/cm3 )を主成分
とする電解液約200ccを電槽に注液した。こうして
負極により容量の規制された開放系液リッチ電池を作製
した。90 wt% of the above hydrogen-absorbing alloy particles and carbonyl nickel (INCO nickel powder Type 287 manufactured by Inco Limited Japan, average particle diameter 2.6-3.
(3 μm) 10 wt% was immediately (preferably within several hours) after the alloy etching treatment, mixed for 10 minutes with a planetary ball mill filled with argon gas to deposit fine nickel powder on the hydrogen storage alloy particles. 3% by weight of polyethylene powder as a binder was added to the hydrogen-absorbing alloy particles produced in this way, and made into a paste with ethanol, which had a porosity of 95%, a size of 2 cm × 2 cm, and a thickness of 0.6 m.
600kgf after being filled in a foamed nickel plate of m and dried.
/ Cm 2 and pressurization at 130 ° C in vacuum at 1
The binder was melted by heating for a time to produce a hydrogen storage alloy electrode sheet. This electrode is about 1.0g of hydrogen storage alloy particles
Contains. A nickel lead wire was welded to this to form a negative electrode. In addition, the positive electrode mixture containing nickel hydroxide as the main component had the same porosity of 95% as the negative electrode and a size of 2 cm × 2 c.
A foamed nickel plate having a thickness of m and a thickness of 1 mm was filled and a nickel lead wire was welded to produce a positive electrode. The one negative electrode and the two positive electrodes thus produced were each wrapped with a hydrophilic polypropylene separator having a thickness of 0.15 mm, the negative electrode was sandwiched between the two positive electrodes, and an acrylic resin plate was placed from both sides. Tightened with. This was placed in a battery case, and about 200 cc of an electrolytic solution containing a potassium hydroxide aqueous solution (density 1.30 g / cm 3 ) as a main component was poured into the battery case. Thus, an open system liquid-rich battery whose capacity was regulated by the negative electrode was produced.
【0016】図1は、上記の電池を20℃において10
0mAの電流で6時間充電し、50mAの電流で終止電
圧0.8Vまで放電する充放電サイクルを行った時の負
極合金1g当たりの放電容量の変化を示す。また、図2
は高率放電特性を示したもので、合金の単位重量当たり
50mA/gの電流で放電した時の容量を1として、各
放電電流密度で放電した時の容量比率を示したものであ
る。ここで、比較例1は、エッチング処理もニッケル微
粉末の添加も行わなかった水素吸蔵合金粒子から構成し
た電極を用いたもの、比較例2は、フッ化水素酸水溶液
によるエッチング処理を行わなずに、実施例1と同様の
カーボニルニッケルを10wt%添加した水素吸蔵合金
粒子から構成した電極を用いたものである。FIG. 1 shows the above battery at 10 ° C. for 10 hours.
4 shows a change in discharge capacity per 1 g of the negative electrode alloy when a charging / discharging cycle of charging at 0 mA for 6 hours and discharging at 50 mA to a final voltage of 0.8 V was performed. FIG.
Shows high rate discharge characteristics, and shows the capacity ratio when discharged at each discharge current density, with the capacity when discharged at a current of 50 mA / g per unit weight of the alloy being 1. Here, Comparative Example 1 uses an electrode composed of hydrogen-absorbing alloy particles which is not subjected to etching treatment or addition of nickel fine powder, and Comparative Example 2 is not subjected to etching treatment with a hydrofluoric acid aqueous solution. In addition, the same electrode as that used in Example 1 was used, which was composed of hydrogen storage alloy particles to which 10% by weight of carbonyl nickel was added.
【0017】比較例1は、最大放電容量が280mAh
/g程度と少なく、サイクル特性も悪く、300mA/
gの高率ではほとんど放電できない状態となった。比較
例2は、放電容量は340mAh/g程度でサイクル特
性も無添加のものと比べるとやや向上が見られた。しか
し、300mA/gの放電ではほとんど容量の向上は見
られなかった。一方、本実施例のものは、最大放電容量
が400mAh/gと大きく向上し、サイクル特性も改
善され、高率放電特性においても顕著な向上が認められ
た。これは電極活性と耐食性に優れるニッケル微粉末の
一部が水素吸蔵合金の表面と酸化膜を介することなく直
接接触しているため、電極活性が大幅に向上し、放電容
量の増加および高率放電特性の向上、さらにサイクル特
性も改善されたことによるものと考えられる。比較例2
のようにエッチング処理せずに単にニッケル微粉末を付
着させたものでは、ニッケル微粉末と水素吸蔵合金表面
との直接の結合が十分でなく、電極活性があまり向上し
ないものと考えられる。このため集電性は若干改善さ
れ、放電容量は少し向上するが、高率放電特性はほとん
ど改善されなかったものと思われる。In Comparative Example 1, the maximum discharge capacity is 280 mAh.
/ G / g, low cycle characteristics, 300 mA /
At a high rate of g, almost no discharge was possible. In Comparative Example 2, the discharge capacity was about 340 mAh / g, and the cycle characteristics were slightly improved as compared with the additive-free one. However, almost no improvement in capacity was observed at a discharge of 300 mA / g. On the other hand, in the case of this example, the maximum discharge capacity was greatly improved to 400 mAh / g, the cycle characteristics were also improved, and the high rate discharge characteristics were also markedly improved. This is because part of the nickel fine powder, which has excellent electrode activity and corrosion resistance, is in direct contact with the surface of the hydrogen storage alloy without passing through the oxide film, resulting in a significant improvement in electrode activity, an increase in discharge capacity, and a high rate discharge. It is considered that this is because the characteristics are improved and the cycle characteristics are also improved. Comparative Example 2
It is considered that, in the case where the nickel fine powder is simply adhered without etching treatment as described above, the direct bonding between the nickel fine powder and the surface of the hydrogen storage alloy is not sufficient, and the electrode activity is not improved so much. Therefore, it is considered that the current collecting property was slightly improved and the discharge capacity was slightly improved, but the high rate discharge property was hardly improved.
【0018】《実施例2》実施例1と同様に、フッ化水
素酸水溶液でエッチングした後、遊星ボールミルでカー
ボニルニッケル粉末と混合してニッケル微粉末を表面に
付着させた水素吸蔵合金粒子を作製した。この水素吸蔵
合金粒子をエタノールでペーストにし、実施例1と同様
の発泡状ニッケル板に充填し、加圧して電極を作製し、
これを真空中において800℃で30分間熱処理し、直
ちに急冷した。EPMA(電子線マイクロアナライザ
ー)で分析した結果、合金内にNiが若干(0.2μm
程度)拡散していることがわかった。高温での保持時間
が長すぎると、表面のニッケル微粉末が完全に水素吸蔵
合金内部に拡散するので、30分程度、長くとも1時間
以内が適当であった。Example 2 Similar to Example 1, hydrogen-absorbing alloy particles were prepared by etching with a hydrofluoric acid aqueous solution and then mixing with carbonyl nickel powder in a planetary ball mill to deposit fine nickel powder on the surface. did. The hydrogen-absorbing alloy particles were made into a paste with ethanol, and the same foamed nickel plate as in Example 1 was filled and pressed to prepare an electrode,
This was heat-treated in vacuum at 800 ° C. for 30 minutes, and immediately quenched. As a result of analysis by EPMA (electron beam microanalyzer), some Ni (0.2 μm) was found in the alloy.
It was found to be diffused. If the holding time at high temperature is too long, the fine nickel powder on the surface will be completely diffused inside the hydrogen storage alloy, so about 30 minutes, and at most 1 hour or less was appropriate.
【0019】この電極を負極に用いた開放系液リッチ電
池の特性を図1および図2に示す。本実施例では、実施
例1に比べて放電容量、高率放電特性ともにさらなる改
善が認められた。比較例3は、エッチング処理せずにカ
ーボニルニッケルを10wt%添加した水素吸蔵合金粒
子で構成した電極を真空中において800℃で30分熱
処理した負極を用いたものである。比較例3は、放電容
量は360mAh/gであり、カーボニルニッケルを添
加するも高温での処理はしない比較例2よりは20mA
h/g程度向上した。しかし、エッチング処理した実施
例2(放電容量430mAh/g)ほどは大きな改善は
見られなかった。これは合金表面に強固な酸化膜を有す
るので、熱処理によってもニッケル微粉末の水素吸蔵合
金表面への拡散がほとんどなく、電極活性の顕著な向上
がないためと考えられる。The characteristics of an open system liquid-rich battery using this electrode as the negative electrode are shown in FIGS. 1 and 2. In this example, further improvement in discharge capacity and high rate discharge characteristics was observed as compared with Example 1. Comparative Example 3 uses a negative electrode obtained by heat-treating an electrode composed of hydrogen-occlusion alloy particles to which 10% by weight of carbonyl nickel was added without heat treatment in vacuum at 800 ° C. for 30 minutes. Comparative Example 3 has a discharge capacity of 360 mAh / g and is 20 mA higher than Comparative Example 2 in which carbonyl nickel is added but not treated at high temperature.
It was improved by about h / g. However, no significant improvement was observed as compared with Example 2 (discharge capacity 430 mAh / g) which was subjected to etching treatment. It is considered that this is because the alloy surface has a strong oxide film, so that the nickel fine powder hardly diffuses to the surface of the hydrogen storage alloy even by the heat treatment, and the electrode activity is not significantly improved.
【0020】《実施例3》所定量のZr,Mn,V,C
r,およびNiを高周波溶解炉のルツボに入れて溶解
し、これを水冷された鋳型に流し込み、主たる合金相が
C15型ラーベス(Laves)相であるAB2タイプ
のZrMn0.6 V0.1 Cr0.2 Ni1.2を作製した。こ
のようにして作製した合金を真空中において1100℃
で6時間熱処理した後、機械粉砕で粒径約22μmの合
金粒子を得た。この合金粒子を水素ガス中において90
0℃で2時間還元処理し、表面の酸化膜を薄くした。実
施例1と同様の方法でオージェー分析した結果、酸化膜
の厚さは0.2μmから0.08μmまで減少してい
た。この水素吸蔵合金粒子95gにニッケルブラック
(日本冶金製Niで、粒径200オングストローム)を
5g添加し、アルゴン雰囲気中で20分間のメカノフュ
ージョン(ホソカワミクロン製使用)を行って合金表面
にニッケルブラックを付着させた。顕微鏡観察から合金
表面にニッケルブラックがほぼ均一に付着していること
がわかった。Example 3 Predetermined amounts of Zr, Mn, V and C
r and Ni were put in a crucible of a high frequency melting furnace and melted, and this was poured into a water-cooled mold, and the main alloy phase was a C15 type Laves phase AB 2 type ZrMn 0.6 V 0.1 Cr 0.2 Ni 1.2. Was produced. The alloy produced in this way is vacuumed at 1100 ° C.
After heat treatment for 6 hours, mechanical pulverization gave alloy particles having a particle size of about 22 μm. 90% of these alloy particles in hydrogen gas
A reduction treatment was performed at 0 ° C. for 2 hours to thin the oxide film on the surface. As a result of Auger analysis performed in the same manner as in Example 1, the thickness of the oxide film was reduced from 0.2 μm to 0.08 μm. To 95 g of the hydrogen storage alloy particles, 5 g of nickel black (Ni, manufactured by Nippon Metallurgy Co., Ltd., particle size: 200 Å) was added, and mechanofusion (using Hosokawa Micron) for 20 minutes was performed in an argon atmosphere to deposit nickel black on the alloy surface. Let From the microscopic observation, it was found that nickel black adhered to the alloy surface almost uniformly.
【0021】上記の水素吸蔵合金粒子を用いて実施例1
と同様にして電極を作製して、開放系液リッチ負極規制
電池を組み立てた。この電池を20℃において、100
mAの電流で6時間充電し、50mAの電流で終止電圧
0.8Vまで放電する充放電サイクルを行った時の負極
合金1g当たりの最大放電容量と、300mA/gで放
電した時の放電容量を後記の表1に示す。後者の放電容
量は、高率放電特性の評価基準とした。比較例4は、還
元処理もニッケルの添加もしない水素吸蔵合金粒子から
構成した負極を用いたもの、比較例5は、水素還元処理
なしで本実施例と同様の方法でニッケルブラックを添加
した水素吸蔵合金粒子から構成した負極を用いたもので
ある。比較例4は、最大放電容量が380mAh/g程
度と少なく、300mA/gでの容量も180mAh/
gと低かった。比較例5は、最大放電容量が395mA
h/g、300mA/gでの容量は210mAh/gと
なり、若干の改善は認められたが、それ程顕著なもので
はなかった。一方、本実施例3のものは、最大放電容量
が420mAh/g、300mA/gでの容量も260
mAh/gと向上した。Example 1 using the above hydrogen storage alloy particles
An electrode was prepared in the same manner as above, and an open system liquid rich negative electrode regulated battery was assembled. This battery is 100 at 100
The maximum discharge capacity per 1 g of the negative electrode alloy and the discharge capacity when discharged at 300 mA / g when the charging / discharging cycle of charging at a current of mA for 6 hours and discharging to a final voltage of 0.8 V at a current of 50 mA were performed. The results are shown in Table 1 below. The latter discharge capacity was used as an evaluation standard for high rate discharge characteristics. Comparative Example 4 uses a negative electrode composed of hydrogen storage alloy particles that is neither reduced nor added with nickel, and Comparative Example 5 is hydrogen added with nickel black in the same manner as in this Example without hydrogen reduction. A negative electrode composed of storage alloy particles is used. Comparative Example 4 has a small maximum discharge capacity of about 380 mAh / g and a capacity of 300 mA / g of 180 mAh / g.
g. Comparative Example 5 has a maximum discharge capacity of 395 mA.
The capacity at h / g and 300 mA / g was 210 mAh / g, and although some improvement was recognized, it was not so remarkable. On the other hand, in Example 3, the maximum discharge capacity was 420 mAh / g, and the capacity at 300 mA / g was 260.
It was improved to mAh / g.
【0022】《実施例4》実施例3と同様に、水素還元
処理後、ニッケルブラックを表面に付着させた水素吸蔵
合金粒子を作製した。この合金粒子を用いて、実施例2
と同様に結着材のポリエチレン粉末を含まない電極を作
製し、これを真空中において600℃で40分間熱処理
した。EPMA分析の結果、合金内にNiが若干(0.
1μm程度)拡散していることがわかった。上記の電極
を負極として、実施例1と同様の開放系液リッチ負極規
制電池を作製した。この電池を20℃において、100
mAの電流で6時間充電し、50mAの電流で終止電圧
0.8Vまで放電する充放電サイクルを行った時の負極
合金1g当たりの最大放電容量と、300mA/gで放
電した時の放電容量を後記の表1に示す。比較例6は、
水素還元処理なしでニッケルブラックを添加した水素吸
蔵合金粒子で構成した電極を、本実施例と同じ熱処理を
行ったものである。比較例6は、最大放電容量が410
mAh/g、300mA/gでの容量は230mAh/
gとなり、若干の改善は認められた。これに対して、本
実施例4のものは、最大放電容量が440mAh/g、
300mA/gでの容量も290mAh/gと向上し
た。Example 4 In the same manner as in Example 3, after hydrogen reduction treatment, hydrogen storage alloy particles having nickel black adhered to the surface were produced. Example 2 using these alloy particles
In the same manner as in (1), an electrode containing no polyethylene powder as a binder was prepared, and this was heat-treated in vacuum at 600 ° C. for 40 minutes. As a result of EPMA analysis, Ni was slightly contained in the alloy (0.
It was found that they were diffused (about 1 μm). Using the above electrode as a negative electrode, an open system liquid-rich negative electrode regulated battery similar to that of Example 1 was produced. This battery is 100 at 100
The maximum discharge capacity per 1 g of the negative electrode alloy and the discharge capacity when discharged at 300 mA / g when the charging / discharging cycle of charging at a current of mA for 6 hours and discharging to a final voltage of 0.8 V at a current of 50 mA were performed. The results are shown in Table 1 below. Comparative Example 6
An electrode composed of hydrogen storage alloy particles to which nickel black was added without hydrogen reduction treatment was subjected to the same heat treatment as in this example. Comparative Example 6 has a maximum discharge capacity of 410
The capacity at mAh / g and 300mA / g is 230mAh /
It was g, and some improvement was recognized. On the other hand, in Example 4, the maximum discharge capacity was 440 mAh / g,
The capacity at 300 mA / g was also improved to 290 mAh / g.
【0023】《実施例5》実施例3と同様に合金粒子を
水素還元処理した後、気流衝撃法(奈良機械製NHS−
0型使用、アルゴン雰囲気、5分間)によりニッケルブ
ラックを水素吸蔵合金粒子の表面に付着させた。ニッケ
ルブラックの付着割合は、合金95g当たり5gであ
る。この合金粒子を用いて実施例1と同様の方法で電極
を作製し、開放系液リッチ負極規制電池を組み立てた。
この電池を前記と同条件で充放電サイクルを行った時の
負極合金1g当たりの最大放電容量、および300mA
/g放電時の容量は、表1に示すようにほぼ実施例3と
同じ値となり、本発明による効果が確認された。Example 5 The alloy particles were subjected to hydrogen reduction treatment in the same manner as in Example 3 and then subjected to the air flow impact method (NHS-produced by Nara Machine Co., Ltd.).
Nickel black was adhered to the surface of the hydrogen storage alloy particles by using 0 type, argon atmosphere, 5 minutes). The deposition rate of nickel black is 5 g per 95 g of alloy. An electrode was produced using the alloy particles in the same manner as in Example 1 to assemble an open system liquid-rich negative electrode regulated battery.
The maximum discharge capacity per 1 g of the negative electrode alloy when the battery was charged and discharged under the same conditions as above, and 300 mA
As shown in Table 1, the capacity at the time of / g discharge was almost the same as in Example 3, confirming the effect of the present invention.
【0024】《実施例6〜8》水素吸蔵合金粒子は、実
施例1と同じものを実施例1と同条件でエッチング処理
した。一方、これに付着させるニッケル微粉末として、
水アトマイズ法(噴出圧1200kgf/cm2)で作
製したものを分級し、粒径が3μm、5μm、および7
μmの3種類の球状ニッケル微粉末を準備した。次に、
このニッケル微粉末を800℃で10時間水素還元し、
表面の酸化被膜をほぼ除去した。上記のエッチング処理
された水素吸蔵合金粒子85gと各粒径のニッケル微粒
子15gを、アルゴンを充満させたボールミルで1時間
混合した。こうしてニッケル微粉末を付着させた水素吸
蔵合金粒子を作製し、この粒子を用いて実施例1と同様
の方法で電極を作製し、電池を組み立てた。これらの電
池の前記と同様の条件のもとにおける特性を表1に示
す。水素吸蔵合金粒子に付着させるニッケル微粉末の粒
径が3μm(実施例6)および5μm(実施例7)のも
のでは、最大放電容量および300mA/gでの容量の
向上が見られた。しかし、7μm(実施例8)のもので
は、300mA/gでの容量の改善効果が弱かった。従
って、水素吸蔵合金粒子に付着させるニッケル微粉末
は、粒径5μm以下のものが好ましい。これは粒径が大
きくなるにつれて、合金表面の酸化膜に開いた多孔部分
を通して水素吸蔵合金と直接接触する量が減るため、お
よび同一重量添加した際の水素吸蔵合金表面との接触点
が減少するためと考えられる。ニッケル微粉末の添加量
としては、20wt%程度が限度で、これ以上水素吸蔵
能力のないNiを添加するとかえって放電容量の低下を
生じる。<Examples 6 to 8> The same hydrogen storage alloy particles as in Example 1 were etched under the same conditions as in Example 1. On the other hand, as nickel fine powder attached to this,
The particles produced by the water atomizing method (jet pressure 1200 kgf / cm 2 ) were classified, and the particle size was 3 μm, 5 μm, and 7
Three types of spherical nickel fine powder of μm were prepared. next,
This nickel fine powder is reduced with hydrogen at 800 ° C. for 10 hours,
The oxide film on the surface was almost removed. 85 g of the above-described hydrogen-absorbing alloy particles that had been subjected to the etching treatment and 15 g of nickel fine particles of each particle size were mixed for 1 hour in a ball mill filled with argon. In this way, hydrogen storage alloy particles to which the nickel fine powder was attached were prepared, and the particles were used to prepare an electrode in the same manner as in Example 1 to assemble a battery. Table 1 shows the characteristics of these batteries under the same conditions as described above. When the particle size of the nickel fine powder deposited on the hydrogen storage alloy particles was 3 μm (Example 6) and 5 μm (Example 7), the maximum discharge capacity and the capacity at 300 mA / g were improved. However, with 7 μm (Example 8), the capacity improving effect at 300 mA / g was weak. Therefore, the fine nickel powder to be attached to the hydrogen storage alloy particles preferably has a particle size of 5 μm or less. This is because as the particle size increases, the amount of direct contact with the hydrogen storage alloy through the porous part opened in the oxide film on the alloy surface decreases, and the contact point with the hydrogen storage alloy surface when the same weight is added decreases. It is thought to be because. The amount of the fine nickel powder added is limited to about 20 wt%, and the addition of Ni having no hydrogen storage capacity further lowers the discharge capacity.
【0025】《実施例9》粒径200μmのMg粒子2
4gと粒径数μmのカーボニルニッケル58gをアルゴ
ンガス雰囲気中において3日間ボールミルで混合し、メ
カニカルアロイングを行い、粒径10μm程度のMgN
i合金粉末を作製した。この合金を360℃の水素ガス
雰囲気中で10時間還元したものを母合金として用い
た。実施例1と同様の方法でオージェー分析した結果、
合金表面の酸化膜は約0.3μmから約0.15μmに
減少していた。次に、多孔質ニッケルとしてガスアトマ
イズ法で粒径約70μmのNi−Al粒子を作製した。
これをメカニカルグラインダーで機械的に粉砕して粒径
15μm程度とした後、80℃のKOH水溶液中に6時
間浸漬してAlを溶出させ、多孔質ニッケル粉末を作製
した。上記のMgNi合金40gに多孔質ニッケルを1
0g添加し、アルゴンガス雰囲気中において遊星ボール
ミルで10分間混合し、MgNi合金表面に多孔質ニッ
ケルを付着させた。この多孔質ニッケルを付着した水素
吸蔵合金粒子を用いて実施例1と同様の構成で開放系液
リッチ負極規制電池を作製した。比較例7は、何も処理
しないMgNi合金で電極を構成したもの、比較例8
は、水素還元処理なしでMgNi合金粒子に多孔質ニッ
ケルを同じ割合付着させたもので電極を構成したもので
ある。Example 9 Mg particles 2 having a particle size of 200 μm
4 g and 58 g of carbonyl nickel having a particle size of several μm were mixed by a ball mill in an argon gas atmosphere for 3 days, and mechanical alloying was performed to obtain MgN having a particle size of about 10 μm.
An i alloy powder was prepared. This alloy was reduced in a hydrogen gas atmosphere at 360 ° C. for 10 hours and used as a master alloy. As a result of Auger analysis in the same manner as in Example 1,
The oxide film on the surface of the alloy was reduced from about 0.3 μm to about 0.15 μm. Next, Ni—Al particles having a particle size of about 70 μm were prepared as porous nickel by the gas atomizing method.
This was mechanically crushed by a mechanical grinder to have a particle size of about 15 μm, and then immersed in a KOH aqueous solution at 80 ° C. for 6 hours to elute Al, to produce a porous nickel powder. Porous nickel was added to 40 g of the above MgNi alloy.
0 g was added and mixed in a planetary ball mill for 10 minutes in an argon gas atmosphere to adhere porous nickel to the surface of the MgNi alloy. An open system liquid-rich negative electrode regulated battery having the same configuration as in Example 1 was produced using the hydrogen storage alloy particles to which the porous nickel was attached. Comparative Example 7 is one in which the electrode is made of a MgNi alloy which is not treated, Comparative Example 8
Is an electrode formed by depositing porous nickel on MgNi alloy particles in the same proportion without hydrogen reduction treatment.
【0026】これらの電池の特性を表1に示す。比較例
7は、最大放電容量が410mAh/g、300mA/
gでの容量は240mAh/gであり、比較例8は、最
大容量435mAh/g、300mA/gでの容量が2
60mAh/gであり、それぞれ若干の改善は認められ
た。本実施例9は、最大放電容量が540mAh/g、
300mA/gでの容量は410mAh/gと大きく向
上した。また、サイクル特性においても改善効果が認め
られた。なお、多孔質ニッケル粒子の製造方法として
は、Ni−Al以外にもNi−Sn、Ni−Mgあるい
はNi−Ca合金微粒子をガスアトマイズ法、水アトマ
イズ法あるいはメカニカルアローイング法により、また
Ni−Zn合金微粒子はメカニカルアローイング法によ
り作製した後、必要に応じて機械粉砕し、強アルカリ水
溶液でSn、Mg、CaあるいはZnを溶出させて作製
することができる。The characteristics of these batteries are shown in Table 1. Comparative Example 7 has maximum discharge capacities of 410 mAh / g and 300 mA / g.
The capacity at 240 g was 240 mAh / g, and in Comparative Example 8, the maximum capacity was 435 mAh / g and the capacity at 300 mA / g was 2.
It was 60 mAh / g, and a slight improvement was recognized in each case. In Example 9, the maximum discharge capacity was 540 mAh / g,
The capacity at 300 mA / g was greatly improved to 410 mAh / g. In addition, an improvement effect was recognized also in cycle characteristics. As the method for producing the porous nickel particles, in addition to Ni-Al, Ni-Sn, Ni-Mg, or Ni-Ca alloy fine particles may be used by a gas atomizing method, a water atomizing method, or a mechanical arrowing method, or a Ni-Zn alloy. The fine particles can be produced by a mechanical arrowing method, and then mechanically pulverized if necessary, and Sn, Mg, Ca or Zn is eluted with a strong alkaline aqueous solution.
【0027】《実施例10〜12》Ti,V,Cr,L
a,およびNiを原料として、アーク溶解法によってT
i0.3V0.4Cr0.1La0.1Ni0.1 のbcc合金を作製
した。これを水素化粉砕と機械粉砕によって粒径30μ
mの水素吸蔵合金粒子とした。次に、この水素吸蔵合金
粒子を実施例1と同様にフッ化水素酸水溶液でエッチン
グ処理した後、実施例1と同様の方法で電極を作製し
た。この電極を負極として以下のめっき浴を用いて15
分間電解めっきを行い、表面にNi−Zn合金膜を形成
した。水洗した後、31%KOH水溶液に40g/lの
割合でLiOHを溶解した100℃のエッチング液に6
時間浸漬して、めっき膜中のZnを溶出させた。EPM
A観察により、電解めっきによって負極板表面にNi−
Zn合金が均一に存在しているが、エッチングによっ
て、Znがほとんどなくなり、細かなヒビが無数に入っ
ていることが確認された。<Examples 10 to 12> Ti, V, Cr, L
Using a and Ni as raw materials, T by the arc melting method
A bcc alloy of i 0.3 V 0.4 Cr 0.1 La 0.1 Ni 0.1 was prepared. Particle size of 30μ
m hydrogen storage alloy particles. Next, the hydrogen storage alloy particles were subjected to etching treatment with a hydrofluoric acid aqueous solution in the same manner as in Example 1, and then an electrode was prepared in the same manner as in Example 1. Using this electrode as the negative electrode and the following plating bath,
Electroplating was performed for a minute to form a Ni-Zn alloy film on the surface. After rinsing with water, it was added to an etching solution at 100 ° C. in which LiOH was dissolved at a rate of 40 g / l in 31% KOH aqueous solution.
It was immersed for a time to elute Zn in the plated film. EPM
According to A observation, Ni- was formed on the surface of the negative electrode plate by electrolytic plating.
Although the Zn alloy was uniformly present, it was confirmed that Zn was almost completely eliminated by etching and that numerous minute cracks were contained.
【0028】めっき浴: NiSO4・7H2O 330g/l NiCl2・6H2O 45g/l ZnCl2 20g/l H2BO3 37g/l pH 2 陽極 Ni板 電流密度 5A/dm2 Plating bath: NiSO 4 .7H 2 O 330 g / l NiCl 2 .6H 2 O 45 g / l ZnCl 2 20 g / l H 2 BO 3 37 g / l pH 2 Anode Ni plate Current density 5 A / dm 2
【0029】上記の電極を負極として実施例1と同様の
液リッチ負極規制電池を組み立てた。比較例9は、上記
のめっき処理前の電極を用いたもの、比較例10は、エ
ッチング処理しない水素吸蔵合金粒子で電極を構成し、
上記と同様のNi−Znめっきおよび強アルカリによる
エッチング処理を行った電極を用いたもの、比較例11
は、上記においてめっき後の強アルカリによるエッチン
グ処理を行わなかった電極を用いたものである。これら
の電池の特性を表1に示す。比較例10、11は、比較
例9と比べると最大放電容量、および高率放電特性の向
上は見られたが、本実施例10のものほど大幅な向上は
なかった。なお、Ni−Znめっきの代わりにNi−S
nめっき(実施例11)またはNi−Coめっき(実施
例12)をし、強アルカリでエッチング処理した電極を
用いたものでも同様な効果が認められた。A liquid-rich negative electrode regulated battery similar to that of Example 1 was assembled using the above electrode as a negative electrode. Comparative Example 9 uses the electrode before the plating treatment described above, and Comparative Example 10 configures the electrode with hydrogen storage alloy particles that are not subjected to etching treatment,
Comparative example 11 using an electrode subjected to the same Ni-Zn plating and etching treatment with a strong alkali as described above.
In the above, an electrode not subjected to etching treatment with a strong alkali after plating is used. The characteristics of these batteries are shown in Table 1. In Comparative Examples 10 and 11, the maximum discharge capacity and the high rate discharge characteristics were improved as compared with Comparative Example 9, but they were not significantly improved as compared with Example 10. Incidentally, instead of Ni-Zn plating, Ni-S
The same effect was observed even when using an electrode that was subjected to n-plating (Example 11) or Ni-Co plating (Example 12) and subjected to etching treatment with a strong alkali.
【0030】《実施例13》実施例10の負極板を真空
中において900℃で10分間熱処理した。この電極を
用いると、表1に示すように実施例12と比べさらなる
特性の向上が見られた。Example 13 The negative electrode plate of Example 10 was heat treated in vacuum at 900 ° C. for 10 minutes. Using this electrode, as shown in Table 1, further improvement in characteristics was observed as compared with Example 12.
【0031】《実施例14》実施例10と同様にTi
0.3V0.4Cr0.1La0.1Ni0.1 のbcc合金を作製
し、水素化粉砕と機械粉砕により粒径約30μmの粒子
とし、これを実施例1と同様にフッ化水素酸水溶液でエ
ッチング処理した。この水素吸蔵合金粒子10gを、2
0g/lのSnCl2・2H2Oと6NのHClを10m
l/l含む処理液に25℃で1分間浸漬し、次に0.5
g/lのPdCl2・2H2Oと6NのHClを5ml/
l含む処理液に25℃で1分間浸漬した。十分水洗した
後、以下に示す無電解めっき浴に60℃で30分間浸漬
することにより、表面にニッケルめっきをした。<< Embodiment 14 >> Similar to Embodiment 10, Ti
A bcc alloy of 0.3 V 0.4 Cr 0.1 La 0.1 Ni 0.1 was prepared, and hydrogenated and mechanically ground to give particles having a particle size of about 30 μm, which were subjected to etching treatment with a hydrofluoric acid aqueous solution in the same manner as in Example 1. 2 g of 10 g of the hydrogen storage alloy particles
0 g / l SnCl 2 · 2H 2 O and 6N HCl for 10 m
Immerse in 1 / l treatment solution for 1 minute at 25 ° C, then 0.5
5 ml / g of PdCl 2 .2H 2 O and 6N HCl
It was immersed in a treatment liquid containing 1 l at 25 ° C. for 1 minute. After thoroughly washing with water, the surface was plated with nickel by immersing it in the electroless plating bath shown below at 60 ° C. for 30 minutes.
【0032】無電解めっき浴: NiSO4・6H2O 25g/l ピロリン酸ナトリウム 50g/l ホスフィン酸ナトリウム 25g/l pH 11The electroless plating bath: NiSO 4 · 6H 2 O 25g / l sodium pyrophosphate 50 g / sodium l phosphinate 25 g / l pH 11
【0033】EPMA分析の結果、水素吸蔵合金粒子表
面にNiが0.5μm程度、多孔質状になって付着して
いることが確認された。上記の水素吸蔵合金粒子を用い
て実施例1と同様の方法で電極を作製し、液リッチ負極
規制電池を組み立てた。この電池の特性は、表1に示す
ように、最大放電容量が500mAh/g、300mA
/gでの容量が260mAh/gと向上した。As a result of EPMA analysis, it was confirmed that Ni was deposited on the surface of the hydrogen storage alloy particles in a porous form of about 0.5 μm. An electrode was prepared using the above hydrogen storage alloy particles in the same manner as in Example 1 to assemble a liquid-rich negative electrode regulated battery. As shown in Table 1, the characteristics of this battery are that the maximum discharge capacity is 500 mAh / g, 300 mA.
/ G capacity was improved to 260 mAh / g.
【0034】《実施例15》実施例14の負極板を真空
中において800℃で15分間熱処理した。この電極を
用いた電池は、表1に示すように、実施例14と比べさ
らなる特性の向上が見られた。Example 15 The negative electrode plate of Example 14 was heat-treated in vacuum at 800 ° C. for 15 minutes. As shown in Table 1, the battery using this electrode showed further improvement in characteristics as compared with Example 14.
【0035】[0035]
【表1】 [Table 1]
【0036】以上のように、水素吸蔵合金粒子表面にニ
ッケル粒子を付着させる場合において、酸化膜の厚さが
電極活性に対して非常に大きな影響与える。酸化膜を完
全に除去することは困難であるが、厚さが0.15μm
以下、好ましくは0.1μm以下になると、膜が多孔質
となり、Niの付着によって電極活性が向上する。酸化
膜を薄くする方法としては、高温の水素ガス雰囲気中で
の還元およびフッ化水素酸水溶液によるエッチングが最
適である。As described above, when nickel particles are attached to the surface of the hydrogen storage alloy particles, the thickness of the oxide film has a great influence on the electrode activity. It is difficult to completely remove the oxide film, but the thickness is 0.15 μm
When the thickness is less than 0.1 μm, the film becomes porous, and Ni adheres to improve the electrode activity. As a method for thinning the oxide film, reduction in a high-temperature hydrogen gas atmosphere and etching with a hydrofluoric acid aqueous solution are optimal.
【0037】[0037]
【発明の効果】本発明の水素吸蔵合金電極は、その水素
吸蔵合金粒子の表面に薄い酸化膜を介して電極活性に優
れたNiが存在し、さらにはNiの一部が水素吸蔵合金
と合金化しているため、高容量で高率放電特性、および
サイクル特性に優れている。EFFECTS OF THE INVENTION In the hydrogen storage alloy electrode of the present invention, Ni having excellent electrode activity is present on the surface of the hydrogen storage alloy particles through a thin oxide film, and a part of Ni is alloyed with the hydrogen storage alloy. Therefore, it has high capacity, high rate discharge characteristics and excellent cycle characteristics.
【図1】本発明の実施例1、2および比較例1、2、3
の充放電サイクルにおける負極合金1g当たりの放電容
量の変化を示した図である。1 is an example of the present invention, and FIG. 1 is a comparative example.
FIG. 3 is a diagram showing a change in discharge capacity per 1 g of negative electrode alloy in the charge / discharge cycle of FIG.
【図2】実施例1、2および比較例1、2、3の高率放
電特性を示した図である。FIG. 2 is a diagram showing high rate discharge characteristics of Examples 1 and 2 and Comparative Examples 1, 2 and 3.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 豊口 ▲吉▼徳 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toyoguchi ▲ Yoshi ▼ Toku 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.
Claims (11)
介してニッケル微粉末あるいは多孔質ニッケル膜が付着
している水素吸蔵合金粒子からなることを特徴とする水
素吸蔵合金電極。1. A hydrogen storage alloy electrode comprising hydrogen storage alloy particles having a fine nickel powder or a porous nickel film attached to the surface thereof through an oxide film having a thickness of 0.15 μm or less.
金、体心立方構造を有する固溶体型合金、およびMgN
i系合金からなる群より選ばれる請求項1記載の水素吸
蔵合金電極。2. The hydrogen storage alloy is an AB 2 Laves phase alloy, a solid solution type alloy having a body-centered cubic structure, and MgN.
The hydrogen storage alloy electrode according to claim 1, which is selected from the group consisting of i-based alloys.
請求項1記載の水素吸蔵合金電極。3. The hydrogen storage alloy electrode according to claim 1, wherein the fine nickel powder has a particle size of 5 μm or less.
請求項1記載の水素吸蔵合金電極。4. The hydrogen storage alloy electrode according to claim 1, wherein the fine nickel powder is Raney nickel.
膜の一部が水素吸蔵合金粒子と合金化している請求項1
記載の水素吸蔵合金電極。5. The nickel fine powder or a part of the porous nickel film is alloyed with hydrogen storage alloy particles.
The hydrogen storage alloy electrode as described in the above.
するかあるいはフッ化水素酸水溶液でエッチングして表
面の酸化物の少なくとも一部を除去する工程、および不
活性ガス中で前記水素吸蔵合金粒子の表面に粒径が5μ
m以下のニッケル微粉末をメカノフュージョン、ボール
ミルまたは気流衝撃法により付着させる工程を有するこ
とを特徴とする水素吸蔵合金電極の製造方法。6. A step of reducing at least a part of oxides on the surface by subjecting the hydrogen storage alloy particles to reduction treatment with hydrogen gas or etching with a hydrofluoric acid aqueous solution, and the hydrogen storage alloy in an inert gas. The particle size is 5μ on the surface of the particle
A method for producing a hydrogen storage alloy electrode, comprising a step of depositing nickel fine powder of m or less by mechanofusion, a ball mill or an air flow impact method.
するかあるいはフッ化水素酸水溶液でエッチングして表
面の酸化物の少なくとも一部を除去する工程、および前
記水素吸蔵合金粒子表面に無電解めっきにより多孔質ニ
ッケル膜を付着させる工程を有することを特徴とする水
素吸蔵合金電極の製造方法。7. A step of reducing at least a part of surface oxides by subjecting the hydrogen storage alloy particles to reduction treatment with hydrogen gas or etching with a hydrofluoric acid aqueous solution, and electroless formation on the surface of the hydrogen storage alloy particles. A method for producing a hydrogen storage alloy electrode, comprising a step of depositing a porous nickel film by plating.
するかあるいはフッ化水素酸水溶液でエッチングして表
面の酸化物の少なくとも一部を除去する工程、前記水素
吸蔵合金粒子により極板を作製する工程、前記極板の表
面にNi−Zn、Ni−SnおよびNi−Coのいずれ
かの合金を電解めっきで形成する工程、および前記めっ
きされた極板を強アルカリ水溶液中に浸漬して前記合金
中の亜鉛、スズまたはコバルトを溶解する工程を有する
ことを特徴とする水素吸蔵合金電極の製造方法。8. A step of reducing at least a part of oxides on the surface by subjecting the hydrogen-absorbing alloy particles to a reduction treatment with hydrogen gas or etching with a hydrofluoric acid aqueous solution, and producing an electrode plate from the hydrogen-absorbing alloy particles. The step of forming an alloy of Ni-Zn, Ni-Sn, and Ni-Co on the surface of the electrode plate by electrolytic plating, and immersing the plated electrode plate in a strong alkaline aqueous solution. A method for producing a hydrogen storage alloy electrode, comprising a step of dissolving zinc, tin or cobalt in the alloy.
請求項6、7または8記載の水素吸蔵合金電極の製造方
法。9. The method for manufacturing a hydrogen storage alloy electrode according to claim 6, further comprising a step of sintering in vacuum.
法、ガスアトマイズ法またはメカニカルアロイ法により
ニッケルと強アルカリ水溶液に溶ける元素からなるニッ
ケル合金微粒子を作製する工程、および得られたニッケ
ル合金微粒子を強アルカリ水溶液中に浸漬し、ニッケル
合金微粒子中の溶出成分を除去する工程により作製した
ものである請求項6記載の水素吸蔵合金電極の製造方
法。10. A step of producing nickel alloy fine particles, wherein the fine nickel powder is nickel and an element soluble in a strong alkaline aqueous solution by a water atomizing method, a gas atomizing method or a mechanical alloying method, and the obtained nickel alloy fine particles are treated with a strong alkali. 7. The method for producing a hydrogen storage alloy electrode according to claim 6, wherein the hydrogen storage alloy electrode is manufactured by a step of immersing the electrode in an aqueous solution to remove elution components in the nickel alloy fine particles.
(ただし、XはAl,Sn、Mg、CaおよびZnから
なる群より選ばれる少なくとも1の元素)である請求項
10記載の水素吸蔵合金電極の製造方法。11. The nickel alloy fine particles are Ni—X.
(However, X is at least one element selected from the group consisting of Al, Sn, Mg, Ca, and Zn.) The method for producing a hydrogen storage alloy electrode according to claim 10.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP8128622A JPH09312157A (en) | 1996-05-23 | 1996-05-23 | Hydrogen storage alloy electrode and manufacture thereof |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP8128622A JPH09312157A (en) | 1996-05-23 | 1996-05-23 | Hydrogen storage alloy electrode and manufacture thereof |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH09312157A true JPH09312157A (en) | 1997-12-02 |
Family
ID=14989354
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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JP8128622A Pending JPH09312157A (en) | 1996-05-23 | 1996-05-23 | Hydrogen storage alloy electrode and manufacture thereof |
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Country | Link |
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10275631A (en) * | 1996-12-27 | 1998-10-13 | Canon Inc | Powder material, electrode structure, manufacture of them, and secondary battery |
JP2002541646A (en) * | 1999-04-08 | 2002-12-03 | オヴォニック バッテリー カンパニー インコーポレイテッド | Active electrode composition containing Raney-based catalyst and material |
EP1093171A3 (en) * | 1999-09-09 | 2005-01-19 | Canon Kabushiki Kaisha | Alkaline rechargeable batteries and process for the production of said rechargeable batteries |
US6902845B2 (en) | 2001-03-09 | 2005-06-07 | Canon Kabushiki Kaisha | Alkaline rechargeable battery and process for the production thereof |
JP2007184148A (en) * | 2006-01-06 | 2007-07-19 | Furukawa Battery Co Ltd:The | Method of manufacturing pocket type hydrogen storage alloy electrode |
WO2016152833A1 (en) * | 2015-03-25 | 2016-09-29 | 三井金属鉱業株式会社 | Method for producing electrode for lithium secondary batteries |
-
1996
- 1996-05-23 JP JP8128622A patent/JPH09312157A/en active Pending
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10275631A (en) * | 1996-12-27 | 1998-10-13 | Canon Inc | Powder material, electrode structure, manufacture of them, and secondary battery |
JP2002541646A (en) * | 1999-04-08 | 2002-12-03 | オヴォニック バッテリー カンパニー インコーポレイテッド | Active electrode composition containing Raney-based catalyst and material |
EP1093171A3 (en) * | 1999-09-09 | 2005-01-19 | Canon Kabushiki Kaisha | Alkaline rechargeable batteries and process for the production of said rechargeable batteries |
US6902845B2 (en) | 2001-03-09 | 2005-06-07 | Canon Kabushiki Kaisha | Alkaline rechargeable battery and process for the production thereof |
JP2007184148A (en) * | 2006-01-06 | 2007-07-19 | Furukawa Battery Co Ltd:The | Method of manufacturing pocket type hydrogen storage alloy electrode |
WO2016152833A1 (en) * | 2015-03-25 | 2016-09-29 | 三井金属鉱業株式会社 | Method for producing electrode for lithium secondary batteries |
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