JP3533766B2 - Hydrogen storage alloy electrode and method for producing the same - Google Patents
Hydrogen storage alloy electrode and method for producing the sameInfo
- Publication number
- JP3533766B2 JP3533766B2 JP17848095A JP17848095A JP3533766B2 JP 3533766 B2 JP3533766 B2 JP 3533766B2 JP 17848095 A JP17848095 A JP 17848095A JP 17848095 A JP17848095 A JP 17848095A JP 3533766 B2 JP3533766 B2 JP 3533766B2
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- Prior art keywords
- hydrogen storage
- storage alloy
- electrode
- hydroxide
- alloy electrode
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- 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
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Description
【０００１】[0001]
【産業上の利用分野】本発明は水素吸蔵合金を使用した
ニッケル−水素蓄電池の負極の水素吸蔵合金電極および
その製造法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrogen storage alloy electrode for a negative electrode of a nickel-hydrogen storage battery using a hydrogen storage alloy and a method for producing the same.
【０００２】[0002]
【従来の技術】各種の電源として広く使われている蓄電
池としては鉛蓄電池、アルカリ蓄電池およびリチウムイ
オン電池等がある。このうちアルカリ蓄電池は高出力で
信頼性が高く、小形化も可能などの理由で各種ポ−タブ
ル機器用あるいは産業用として使われてきた。2. Description of the Related Art Storage batteries widely used as various power sources include lead storage batteries, alkaline storage batteries and lithium ion batteries. Of these, alkaline storage batteries have been used for various portable devices or industrial applications for any reason that they have high output, high reliability, and can be miniaturized.
【０００３】このアルカリ蓄電池においては、正極にニ
ッケル極、負極にカドミウムを用いたニッケル−カドミ
ウム蓄電池と正極はニッケル極で負極に水素を電気化学
的に吸蔵−放出する水素吸蔵合金を用いたニッケル−水
素蓄電池が主流を占めている。In this alkaline storage battery, a nickel-cadmium storage battery using a nickel electrode for the positive electrode and cadmium for the negative electrode, and a nickel electrode for the positive electrode is a nickel electrode and a nickel-hydrogen storage alloy that electrochemically absorbs and desorbs hydrogen. Hydrogen storage batteries are the mainstream.
【０００４】ニッケル−水素蓄電池の負極として使用す
る水素吸蔵合金電極の理論容量はカドミウム極より大き
く、亜鉛極のような変形やデンドライトの形成もないこ
とから、高容量・長寿命・無公害であるという特徴をも
っている。The theoretical capacity of the hydrogen storage alloy electrode used as the negative electrode of the nickel-hydrogen storage battery is larger than that of the cadmium electrode, and since it does not deform like the zinc electrode or form dendrites, it has high capacity, long life and no pollution. It has the feature.
【０００５】このような水素吸蔵合金電極に用いられる
合金として、ＡＢ5タイプのＬａ（またはＭｍ）−Ｎｉ
系の多元系合金がよく知られている。しかし、この合金
系は水素吸蔵合金としては比較的放電容量が小さいこ
と、電池電極の初期活性がやや悪いこと、材料コストが
高いなどの問題を有している。As an alloy used for such a hydrogen storage alloy electrode, AB 5 type La (or Mm) -Ni is used.
Multi-component alloys of the series are well known. However, this alloy system has problems that the discharge capacity is relatively small as a hydrogen storage alloy, the initial activity of the battery electrode is rather poor, and the material cost is high.
【０００６】ＡＢ2タイプのＬａｖｅｓ相水素吸蔵合金
やＴｉＶＣｒＮｉ系合金を主流とした体心立方構造（ｂ
ｃｃ）タイプの水素吸蔵合金は水素吸蔵能がＡＢ5タイ
プ水素吸蔵合金よりも高く、高容量の電極材料として近
年注目を集めている。A body-centered cubic structure (b) mainly composed of AB 2 type Laves phase hydrogen storage alloys and TiVCrNi alloys
The cc) type hydrogen storage alloy has a higher hydrogen storage capacity than the AB 5 type hydrogen storage alloy, and has recently attracted attention as a high capacity electrode material.
【０００７】しかし、ＡＢ2タイプのＬａｖｅｓ相水素
吸蔵合金やｂｃｃタイプの水素吸蔵合金も、高容量であ
るが初期活性が非常に悪い（充放電サイクル初期で低い
容量しか得られない）という問題を有している。However, the AB 2 type Laves phase hydrogen storage alloy and the bcc type hydrogen storage alloy also have a problem that they have a high capacity but very poor initial activity (only a low capacity is obtained at the beginning of the charge / discharge cycle). Have
【０００８】[0008]
【発明が解決しようとする課題】初期活性が悪い電池の
場合、メーカー側で容量が充分上がるまで充放電サイク
ルを繰り返す必要があり、コスト高の原因となる。In the case of a battery having a poor initial activity, it is necessary for the manufacturer to repeat the charging / discharging cycle until the capacity is sufficiently increased, which causes a high cost.
【０００９】ＡＢ5タイプの水素吸蔵合金ではアルカリ
処理やエージング処理と呼ばれる前処理が有効と考えら
れているが、工程に時間がかかり、やはりコスト高を引
き起こしている。Pretreatments called alkali treatment and aging treatment are considered to be effective for AB 5 type hydrogen storage alloys, but the process takes a long time and also causes a high cost.
【００１０】一方、とくに初期活性の遅いＡＢ2タイプ
のＬａｖｅｓ相水素吸蔵合金を用いたニッケル−水素蓄
電池の場合、この問題は実用化に対して非常に重要とな
ってくる。そのため、ＡＢ2タイプのＬａｖｅｓ相水素
吸蔵合金電極の製法などに多くの提案がなされている。
例えば、水素吸蔵合金中にＬａＮｉ2などの合金相を形
成させたり（特開平５−２０９３２４号公報）、ニッケ
ル、銅、オキシ水酸化ニッケルの添加（特開平４−２５
９７５１号公報など）が提案されている。On the other hand, this problem becomes very important for practical use in the case of a nickel-hydrogen storage battery using an AB 2 type Laves phase hydrogen storage alloy having a slow initial activity. Therefore, many proposals have been made for a method of manufacturing an AB 2 type Laves phase hydrogen storage alloy electrode.
For example, an alloy phase such as LaNi 2 is formed in a hydrogen storage alloy (Japanese Patent Laid-Open No. 5-209324), nickel, copper, nickel oxyhydroxide is added (Japanese Patent Laid-Open No. 4-25).
9751, etc.) has been proposed.
【００１１】しかし、いずれの方法も作業工程に時間、
手間がかかりコスト高につながる等の欠点がある。However, both of the methods require time for the work process,
There are drawbacks such as time-consuming and costly.
【００１２】本発明は上記課題に鑑み、低コスト化のた
めの簡便な手法により充分な放電容量が充放電サイクル
の初期から得られ、かつ高容量な水素吸蔵合金電極を提
供するものである。In view of the above problems, the present invention provides a hydrogen storage alloy electrode having a high capacity, which has a sufficient discharge capacity obtained from the beginning of a charge / discharge cycle by a simple method for cost reduction.
【００１３】[0013]
【課題を解決するための手段】本発明は、前記課題を解
決するために、負極として金属水酸化物と水素を電気化
学的に吸蔵放出する水素吸蔵合金を含有する水素吸蔵合
金電極を用いたことを特徴とするものである。In order to solve the above problems, the present invention uses a hydrogen storage alloy electrode containing a metal hydroxide and a hydrogen storage alloy that electrochemically stores and releases hydrogen as a negative electrode. It is characterized by that.
【００１４】また、前記水素吸蔵合金は一般式がＡＢ5
で表されるか、一般式がＡＢ2で表され、合金相が金属
間化合物のＬａｖｅｓ相に属し、その結晶構造が少なく
とも六方対称のＣ１４型または立方対称のＣ１５型であ
る水素吸蔵合金あるいはｂｃｃタイプの合金である。The hydrogen storage alloy has a general formula of AB 5
Or a general formula is represented by AB 2 , the alloy phase belongs to the Laves phase of the intermetallic compound, and its crystal structure is at least hexagonal C14 type or cubic C15 type hydrogen storage alloy or bcc It is a type of alloy.
【００１５】さらに、前記金属水酸化物は希土類元素
（Ｌａ、Ｃｅなど）の水酸化物、水酸化ニッケルまたは
水酸化コバルトを少なくとも一種類含有する金属水酸化
物である。Further, the metal hydroxide is a hydroxide of a rare earth element (La, Ce, etc.), a metal hydroxide containing at least one kind of nickel hydroxide or cobalt hydroxide.
【００１６】また、前記電極の金属水酸化物の添加方法
としては、水素吸蔵合金と粒径１μｍ以下の金属水酸化
物粉末を直接機械的に充分混合する方法あるいは金属イ
オンを含む溶液から金属水酸化物を水素吸蔵合金または
水素吸蔵合金電極に析出させる方法が有効である。As a method of adding the metal hydroxide to the electrode, a method of directly mechanically mixing a hydrogen storage alloy and a metal hydroxide powder having a particle size of 1 μm or less, or a solution containing metal ions is used. A method of depositing an oxide on a hydrogen storage alloy or a hydrogen storage alloy electrode is effective.
【００１７】[0017]
【作用】以上のような構成により、本発明の水素吸蔵合
金電極は初期活性を向上させることができる。つまり、
電解液中では水素吸蔵合金成分中のＬａ、Ｚｒあるいは
Ｔｉが合金表面に緻密で強固な酸化物層を形成し、水素
吸蔵合金電極としての活性が低くなっているが、水素吸
蔵合金電極中に水素吸蔵合金とともに金属水酸化物を添
加することによって、これら金属水酸化物は水素の吸蔵
−放出に対して高活性な電極反応点として作用する。そ
の結果、水素吸蔵合金電極の初期活性が向上し、充放電
サイクル初期でより大きな放電容量が得られる。但し、
混合する金属水酸化物の粒径が大きすぎると、合金表面
への添加（付着）量が減少するため効果が低下する。こ
のため粒径は１μｍ以下であることが望ましい。とくに
希土類元素の水酸化物は電極活性付与に有効である。希
土類元素の酸化物はほとんど電極活性を付与しないこと
も鋭意研究した結果判明した。With the above structure, the hydrogen storage alloy electrode of the present invention can improve the initial activity. That is,
In the electrolyte, La, Zr, or Ti in the hydrogen storage alloy component forms a dense and strong oxide layer on the alloy surface, and the activity as the hydrogen storage alloy electrode is low. By adding the metal hydroxide together with the hydrogen storage alloy, these metal hydroxides act as highly active electrode reaction sites for hydrogen storage-release. As a result, the initial activity of the hydrogen storage alloy electrode is improved, and a larger discharge capacity is obtained at the beginning of the charge / discharge cycle. However,
If the particle size of the metal hydroxide to be mixed is too large, the amount of addition (adhesion) to the alloy surface decreases, and the effect decreases. Therefore, the particle size is preferably 1 μm or less. In particular, hydroxides of rare earth elements are effective for imparting electrode activity. It was also found as a result of intensive research that oxides of rare earth elements hardly give electrode activity.
【００１８】よって、本発明の水素吸蔵合金電極は、初
期活性が改善され、高い放電容量を有するアルカリ蓄電
池を与える水素吸蔵合金電極を提供する。Accordingly, the hydrogen storage alloy electrode of the present invention provides a hydrogen storage alloy electrode having an improved initial activity and providing an alkaline storage battery having a high discharge capacity.
【００１９】[0019]
【実施例】以下、本発明の実施例について図を用いて述
べる。Embodiments of the present invention will be described below with reference to the drawings.
【００２０】（実施例１）Ｚｒ、Ｍｎ、Ｖ、Ｃｒ、Ｃ
ｏ、Ｎｉ金属を原料として、アルゴン雰囲気中、アーク
溶解炉で加熱溶解することにより、主たる合金相がＣ１
５型Ｌａｖｅｓ相であり水素を電気化学的に吸蔵放出す
る水素吸蔵合金、ＺｒＭｎ0.5Ｖ0.2Ｃｒ0.2Ｃｏ0.1Ｎｉ
1.1を作製した。次いで、真空中１１００℃で１２時間
熱処理したのち、機械的に粉砕し、粒径が３８−７４μ
ｍの水素吸蔵合金粉末とした。(Example 1) Zr, Mn, V, Cr, C
The main alloy phase is C1 by melting by using an o, Ni metal as a raw material and heating and melting in an arc melting furnace in an argon atmosphere.
ZrMn 0.5 V 0.2 Cr 0.2 Co 0.1 Ni, a hydrogen storage alloy that is a type 5 Laves phase and that stores and releases hydrogen electrochemically
1.1 was created. Then, after heat-treating in vacuum at 1100 ° C. for 12 hours, it is mechanically crushed to give a particle size of 38-74 μm.
m hydrogen storage alloy powder.
【００２１】次にこのようにして得られた水素吸蔵合金
粉末１．０ｇ、水酸化ランタン粉末０．１０ｇ（平均粒
径０．８μｍ）、導電剤としてのカルボニルニッケル粉
末３．０ｇとこれらの結着剤としてのポリエチレン粉末
を全量の３ｗｔ％を加えて混合し、直径２．４５ｃｍの
円盤状ペレットにプレス成形した。このペレットを真空
中、１３０℃１時間加熱し、結着剤を溶融させて水素吸
蔵合金電極とした。Next, 1.0 g of the hydrogen storage alloy powder thus obtained, 0.10 g of lanthanum hydroxide powder (average particle size 0.8 μm), 3.0 g of carbonyl nickel powder as a conductive agent, and the combination of these. 3 wt% of the total amount of polyethylene powder as a binder was added and mixed, and pressed into a disk-shaped pellet having a diameter of 2.45 cm. The pellets were heated in vacuum at 130 ° C. for 1 hour to melt the binder and form a hydrogen storage alloy electrode.
【００２２】この水素吸蔵合金電極にニッケル線のリー
ドを取り付けたものを負極とし、正極として過剰の電気
容量を有する焼結式ニッケル極を用いた。比重１．３０
ｇ／ｃｍ3の水酸化カリウム水溶液からなる電解液が豊
富な条件下で水素吸蔵合金負極で容量規制を行なった開
放系の電池を作製した。この電池を用いて、２５℃にお
ける充放電サイクルでの放電容量を測定し、単電池試験
を行った。なお、充電は１００ｍＡ×５．５時間、放電
は５０ｍＡで端子電圧が０．８Ｖになるまで行った。こ
の電極を電極Ａとする。A nickel wire lead attached to the hydrogen storage alloy electrode was used as a negative electrode, and a sintered nickel electrode having an excessive electric capacity was used as a positive electrode. Specific gravity 1.30
An open system battery was produced in which the capacity was regulated by the hydrogen storage alloy negative electrode under the condition that the electrolytic solution containing the g / cm 3 potassium hydroxide aqueous solution was abundant. Using this battery, the discharge capacity in a charge / discharge cycle at 25 ° C. was measured and a single cell test was conducted. The charging was 100 mA × 5.5 hours and the discharging was 50 mA until the terminal voltage became 0.8V. This electrode is called electrode A.
【００２３】また、水酸化ランタンに代えて、水酸化セ
リウム、水酸化ニッケル、水酸化コバルトを用いて作製
した電極をそれぞれ電極Ｂ、Ｃ、Ｄとする。比較例とし
て水酸化物を添加せずに作製した電極を電極Ｓとする。Electrodes prepared by using cerium hydroxide, nickel hydroxide and cobalt hydroxide in place of lanthanum hydroxide are electrodes B, C and D, respectively. As a comparative example, an electrode prepared without adding a hydroxide is referred to as an electrode S.
【００２４】電極Ａ〜Ｄ、Ｓの単電池試験の結果を図１
に示す。図１から明らかなように、本発明の水素吸蔵合
金電極Ａ〜Ｄは、充放電サイクル初期で電極活性が向上
し、従来の水素吸蔵合金電極Ｓより高い容量を示した。The results of the unit cell test of the electrodes A to D and S are shown in FIG.
Shown in. As is clear from FIG. 1, the hydrogen storage alloy electrodes A to D of the present invention had improved electrode activity at the beginning of the charge / discharge cycle and showed a higher capacity than the conventional hydrogen storage alloy electrode S.
【００２５】これは、金属水酸化物を添加したことで、
電極の電気化学的な水素の吸蔵−放出に対する活性が大
きくなり、サイクル初期の放電容量が増加したと考え
る。This is because the addition of metal hydroxide
It is considered that the activity of the electrode for electrochemical hydrogen storage-release is increased and the discharge capacity at the beginning of the cycle is increased.
【００２６】（実施例２）Ｍｍ（ミッシュメタル、希土
類元素の混合物）、Ｎｉ、Ｍｎ、Ａｌ、Ｃｏを組成とし
て、アルゴン雰囲気中、アーク溶解炉で加熱溶解するこ
とにより、ＡＢ5タイプの電気化学的に吸蔵−放出する
水素吸蔵合金、ＭｍＮｉ1.3Ｍｎ0.4Ａｌ0. 3Ｃｏ0.75を
作製した。次いで、真空中１１００℃で１２時間熱処理
したのち、機械的に粉砕し、粒径が３８−７４μｍの水
素吸蔵合金粉末とした。(Example 2) AB 5 type electrochemistry was performed by melting Mm (mixture of misch metal and rare earth element), Ni, Mn, Al and Co in an argon atmosphere by heating and melting in an arc melting furnace. occluding - the hydrogen storage alloy to release to prepare a MmNi 1.3 Mn 0.4 Al 0. 3 Co 0.75. Then, after heat-treating in vacuum at 1100 ° C. for 12 hours, it was mechanically pulverized to obtain a hydrogen storage alloy powder having a particle size of 38-74 μm.
【００２７】次に前記実施例１と同様の条件で水素吸蔵
合金電極を作製し、単電池試験を行った。この電極を電
極Ｅとする。Next, a hydrogen storage alloy electrode was prepared under the same conditions as in Example 1 and a single cell test was conducted. This electrode is referred to as an electrode E.
【００２８】また、水酸化ランタンに代えて、水酸化セ
リウム、水酸化ニッケル、水酸化コバルトを用いて作製
した電極をそれぞれ電極Ｆ、Ｇ、Ｈとし、比較例として
水酸化物を添加せずに作製した電極を電極Ｔとする。Electrodes prepared by using cerium hydroxide, nickel hydroxide and cobalt hydroxide instead of lanthanum hydroxide were electrodes F, G and H, respectively. As a comparative example, hydroxide was not added. The produced electrode is referred to as an electrode T.
【００２９】電極Ｅ〜Ｈ、Ｔの単電池試験の結果を図２
に示す。図２から明らかなように、本発明の水素吸蔵合
金電極Ｅ〜Ｈは充放電サイクル初期で電極活性が向上
し、従来の水素吸蔵合金電極Ｔより高い容量を示した。The results of the unit cell test of the electrodes E to H and T are shown in FIG.
Shown in. As is clear from FIG. 2, the hydrogen storage alloy electrodes E to H of the present invention had improved electrode activity at the beginning of the charging / discharging cycle and showed a higher capacity than the conventional hydrogen storage alloy electrode T.
【００３０】（実施例３）Ｔｉ、Ｖ、Ｎｉ金属を原料と
して、アルゴン雰囲気中、アーク溶解炉で加熱溶解する
ことにより、主たる合金相が体心立方構造（ｂｃｃ）相
であり水素を電気化学的に吸蔵放出する水素吸蔵合金、
ＴｉＶ3Ｎｉ0.5を作製した。次いで、真空中１１００℃
で１２時間熱処理したのち、機械的に粉砕し、粒径が３
８−７４μｍの水素吸蔵合金粉末とした。Example 3 Using Ti, V, and Ni metals as raw materials and heating and melting in an argon atmosphere in an arc melting furnace, the main alloy phase is a body-centered cubic (bcc) phase and hydrogen is electrochemically Hydrogen storage alloy that absorbs and releases
TiV 3 Ni 0.5 was prepared. Then, in vacuum at 1100 ° C
After heat-treating for 12 hours, it is mechanically crushed and the particle size is 3
It was a hydrogen storage alloy powder of 8-74 μm.
【００３１】次に前記実施例１と同様の条件で水素吸蔵
合金電極を作製し、単電池試験を行った。この電極を電
極Ｊとする。Next, a hydrogen storage alloy electrode was prepared under the same conditions as in Example 1, and a single cell test was conducted. This electrode is referred to as electrode J.
【００３２】また、水酸化ランタンに代えて、水酸化セ
リウム、水酸化ニッケル、水酸化コバルトを用いて作製
した電極をそれぞれ電極Ｋ、Ｌ，Ｍとし、比較例として
水酸化物を添加せずに作製した電極を電極Ｕとする。Electrodes prepared by using cerium hydroxide, nickel hydroxide and cobalt hydroxide in place of lanthanum hydroxide were electrodes K, L and M, respectively. As a comparative example, hydroxide was not added. The produced electrode is referred to as an electrode U.
【００３３】電極Ｊ〜Ｍ、Ｕの単電池試験の結果を図３
に示す。図３から明らかなように、本発明の水素吸蔵合
金電極Ｊ〜Ｍは、充放電サイクル初期で電極活性が向上
し、従来の水素吸蔵合金電極Ｕより高い容量を示した。The results of the unit cell test of the electrodes J to M and U are shown in FIG.
Shown in. As is clear from FIG. 3, the hydrogen storage alloy electrodes J to M of the present invention had improved electrode activity at the beginning of the charge / discharge cycle and showed a higher capacity than the conventional hydrogen storage alloy electrode U.
【００３４】（実施例４）次に金属水酸化物の添加量に
ついて検討した。前記実施例１に示した水素吸蔵合金に
対する金属水酸化物の重量の比を変えて前記実施例１の
試験を行い、（表１）の結果を得た。添加量が０．０１
以上０．１５以下の範囲で、金属水酸化物の添加効果が
顕著にみられた。０．０１以下では効果が低く、０．１
５以上では水素を吸蔵−放出する水素吸蔵合金の量が相
対的に減少し、かえって容量が低下し、金属水酸化物の
添加効果が発揮されなくなった。また、金属水酸化物の
粒径は、１μｍ以下が初期活性に有効であり数μｍ程度
になると効果が急激に低下した。Example 4 Next, the amount of metal hydroxide added was examined. The test of Example 1 was conducted by changing the weight ratio of the metal hydroxide to the hydrogen storage alloy shown in Example 1, and the results of (Table 1) were obtained. Addition amount is 0.01
In the range of 0.15 or less, the effect of adding the metal hydroxide was remarkably observed. If less than 0.01, the effect is low, and
When it is 5 or more, the amount of hydrogen storage alloy that absorbs and releases hydrogen is relatively decreased, the capacity is rather decreased, and the effect of adding metal hydroxide is not exhibited. Further, the particle size of the metal hydroxide is effective for the initial activity when it is 1 μm or less, and the effect is drastically reduced when the particle size becomes about several μm.
【００３５】[0035]
【表１】 [Table 1]
【００３６】（実施例５）酸化ランタン粉末を熱希硝酸
などの酸に溶解し、この溶液に前記実施例１に示した水
素吸蔵合金粉末を加え、充分に撹拌しながら中和当量以
上の水酸化カリウム水溶液などのアルカリ水溶液を加え
て、水素吸蔵合金粉末粒子表面に水酸化ランタンを析出
させる。生成した沈澱をろ過し、乾燥して表面処理合金
粉末を得た。(Example 5) Lanthanum oxide powder was dissolved in an acid such as hot dilute nitric acid, and the hydrogen-absorbing alloy powder shown in Example 1 was added to this solution. An alkaline aqueous solution such as an aqueous potassium oxide solution is added to deposit lanthanum hydroxide on the surface of the hydrogen storage alloy powder particles. The formed precipitate was filtered and dried to obtain a surface-treated alloy powder.
【００３７】前記実施例１と同様の条件で単電池試験を
行った。但し、水素合金粉末と水酸化ランタン粉末の代
わりに前記表面処理合金粉末を用いた。作製した電極を
電極Ｐとする。電極Ｐの単電池試験の結果も図１に示
す。図１より、水酸化ランタンを液相から生成させるこ
とで、水酸化ランタン粉末を添加するよりも活性がはや
く、かつ高い容量を得た。これは、粉末添加よりも水素
吸蔵合金表面に接触する水酸化ランタンの粒径が小さく
かつ活性点の数が多くなり、大きな活性を与えることが
できたからと考える。A unit cell test was conducted under the same conditions as in Example 1 above. However, the surface-treated alloy powder was used instead of the hydrogen alloy powder and the lanthanum hydroxide powder. The produced electrode is referred to as an electrode P. The result of the unit cell test of the electrode P is also shown in FIG. From FIG. 1, by producing lanthanum hydroxide from the liquid phase, the activity was higher than that when the lanthanum hydroxide powder was added, and a high capacity was obtained. It is considered that this is because the particle size of lanthanum hydroxide in contact with the surface of the hydrogen storage alloy was smaller and the number of active sites was larger than that of the addition of powder, and a large activity could be provided.
【００３８】なお、水素吸蔵合金粒子上に水酸化ランタ
ンを析出させる場合を例に説明したが、水酸化物は水酸
化ランタンに限らず、水酸化セリウム、水酸化ニッケ
ル、水酸化コバルトでもよい。また、水素吸蔵合金粒子
上だけではなく電極表面上などに析出させても有効であ
った。Although the case where lanthanum hydroxide is deposited on the hydrogen storage alloy particles has been described as an example, the hydroxide is not limited to lanthanum hydroxide, and cerium hydroxide, nickel hydroxide, or cobalt hydroxide may be used. In addition, it was effective to deposit not only on the hydrogen storage alloy particles but also on the electrode surface.
【００３９】[0039]
【発明の効果】以上の実施例で明らかなように、水素吸
蔵合金電極中に水酸化ランタンを代表とする金属水酸化
物を添加するだけで水素吸蔵合金電極の初期活性が向上
し、充放電サイクル初期から放電容量が増加する。よっ
て、本発明の水素吸蔵合金電極は、低コストで今まで以
上に初期活性が改善され、高い放電容量を有するニッケ
ル−水素蓄電池の負極の水素吸蔵合金電極を提供するも
のである。As is apparent from the above examples, the initial activity of a hydrogen storage alloy electrode can be improved by simply adding a metal hydroxide typified by lanthanum hydroxide to the hydrogen storage alloy electrode, and the charge and discharge can be improved. The discharge capacity increases from the beginning of the cycle. Therefore, the hydrogen storage alloy electrode of the present invention provides a hydrogen storage alloy electrode for a negative electrode of a nickel-hydrogen storage battery, which has a low cost, improved initial activity, and high discharge capacity.
【図１】本発明の第１の実施例における充放電サイクル
と放電容量の関係図FIG. 1 is a relational diagram of charge / discharge cycle and discharge capacity in the first embodiment of the present invention.
【図２】本発明の第２の実施例における充放電サイクル
と放電容量の関係図FIG. 2 is a diagram showing the relationship between the charge / discharge cycle and the discharge capacity in the second embodiment of the present invention.
【図３】本発明の第３の実施例における充放電サイクル
と放電容量の関係図FIG. 3 is a diagram showing the relationship between the charge / discharge cycle and the discharge capacity in the third embodiment of the present invention.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 辻 庸一郎 大阪府門真市大字門真1006番地 松下電 器産業株式会社内 (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 (56)参考文献 特開 平７−118704（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) H01M 4/24 H01M 4/26 H01M 4/38 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoichiro Tsuji 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Yoshinori Toyokuchi 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (56) References JP-A-7-118704 (JP, A) (58) Fields investigated (Int.Cl. 7 , DB name) H01M 4/24 H01M 4/26 H01M 4/38
Claims (6)
学的に吸蔵放出する水素吸蔵合金とを含有することを特
徴とする水素吸蔵合金電極。1. A hydrogen storage alloy electrode comprising a hydroxide of a rare earth element and a hydrogen storage alloy which stores and releases hydrogen electrochemically.
される水素吸蔵合金であるか、ＡＢ2で表され、合金相
が金属間化合物のＬａｖｅｓ相に属し、その結晶構造が
少なくとも六方対称のＣ１４型または立方対称のＣ１５
型である水素吸蔵合金であるか、結晶構造が体心立方構
造（ｂｃｃ）の水素吸蔵合金である請求項１に記載の水
素吸蔵合金電極。2. The hydrogen storage alloy is a hydrogen storage alloy represented by the general formula AB 5 or represented by AB 2 , and the alloy phase belongs to the Laves phase of the intermetallic compound, and its crystal structure is at least hexagonal. Symmetric C14 type or cubic C15
The hydrogen storage alloy electrode according to claim 1, which is a hydrogen storage alloy of a type or a hydrogen storage alloy having a body-centered cubic structure (bcc) in a crystal structure.
素の水酸化物の重量の比が０．０１から０．１５である
請求項１または２に記載の水素吸蔵合金電極。3. The rare earth element for the hydrogen storage alloy
The hydrogen storage alloy electrode according to claim 1 or 2 , wherein the weight ratio of the elemental hydroxide is 0.01 to 0.15.
と粒径が１μｍ以下である希土類元素の水酸化物とを混
合し成形したことを特徴とする請求項１から３のいずれ
か１項に記載の水素吸蔵合金電極。 4. The hydrogen storage alloy electrode is formed by mixing and molding a hydrogen storage alloy and a hydroxide of a rare earth element having a particle size of 1 μm or less. The hydrogen storage alloy electrode according to.
ウムの少なくともいずれかである請求項１、３または４
のいずれかに記載の水素吸蔵合金電極。 5. The rare earth element is lanthanum or serium.
It is at least any one of um, Claim 1, 3 or 4.
The hydrogen storage alloy electrode according to any one of 1.
造法であって、水素吸蔵合金または水素吸蔵合金電極の
表面に、希土類元素のイオンを含む溶液から前記希土類
元素の水酸化物が析出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法。6. A method for producing the hydrogen storage alloy electrode according to claim 1.
A granulation method, the surface of the hydrogen storage alloy or hydrogen absorbing alloy electrode, the rare earth from a solution containing ions of a rare earth element
A method for producing a hydrogen storage alloy electrode, comprising a step of depositing an elemental hydroxide.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17848095A JP3533766B2 (en) | 1995-07-14 | 1995-07-14 | Hydrogen storage alloy electrode and method for producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17848095A JP3533766B2 (en) | 1995-07-14 | 1995-07-14 | Hydrogen storage alloy electrode and method for producing the same |
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| Publication Number | Publication Date |
|---|---|
| JPH0935708A JPH0935708A (en) | 1997-02-07 |
| JP3533766B2 true JP3533766B2 (en) | 2004-05-31 |
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| CN1072845C (en) * | 1998-08-19 | 2001-10-10 | 冶金工业部钢铁研究总院 | Method for making hydride cathode of nickel-metal hydride storage battery |
| WO2016014356A1 (en) * | 2014-07-25 | 2016-01-28 | Ovonic Battery Company, Inc. | Laves phase-related bcc metal hydride alloys and activation thereof for electrochemical applications |
| US9768445B2 (en) | 2014-07-25 | 2017-09-19 | Ovonic Battery Company, Inc. | Activation of laves phase-related BCC metal hydride alloys for electrochemical applications |
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1995
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