JPH0982319A - Positive active material for alkaline storage battery and manufacture thereof - Google Patents
Positive active material for alkaline storage battery and manufacture thereofInfo
- Publication number
- JPH0982319A JPH0982319A JP7230951A JP23095195A JPH0982319A JP H0982319 A JPH0982319 A JP H0982319A JP 7230951 A JP7230951 A JP 7230951A JP 23095195 A JP23095195 A JP 23095195A JP H0982319 A JPH0982319 A JP H0982319A
- Authority
- JP
- Japan
- Prior art keywords
- cobalt
- active material
- particles
- solid solution
- solution
- 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.)
- Granted
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
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明はアルカリ蓄電池用の
正極活物質に関し、詳しくは水酸化ニッケルとコバルト
化合物とで固溶体粒子となした水酸化ニッケル活物質の
改良に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive electrode active material for an alkaline storage battery, and more particularly to an improvement of a nickel hydroxide active material formed into solid solution particles of nickel hydroxide and a cobalt compound.
【０００２】[0002]
【従来の技術】アルカリ蓄電池用ニッケル正極の製法に
は、ニッケル粉末を焼結した焼結式基板に活物質を充填
するいわゆる焼結式と、ニッケル繊維焼結多孔体や発泡
ニッケル多孔体などの高多孔度のニッケル多孔体にペー
スト状の活物質を充填するいわゆるペースト式とがあ
る。しかし、焼結式は、活物質の充填作業が煩雑であ
り、また基板の高多孔度化に限界があるため、電極の高
エネルギー密度化を図り難いという欠点がある。このた
め、近年では、電池の高エネルギー密度化、低価格化の
要請に応えるべく、高多孔度ニッケル体を用いたペース
ト式のニッケル正極が主流になりつつある。2. Description of the Related Art A method for manufacturing a nickel positive electrode for an alkaline storage battery includes a so-called sintering method in which a sintering type substrate obtained by sintering nickel powder is filled with an active material, and a nickel fiber sintered porous body or a foamed nickel porous body. There is a so-called paste method in which a highly porous nickel porous body is filled with a paste-like active material. However, the sintering method has a drawback that it is difficult to increase the energy density of the electrode because the work of filling the active material is complicated and the increase in the porosity of the substrate is limited. Therefore, in recent years, paste type nickel positive electrodes using a high-porosity nickel body have become mainstream in order to meet the demands for higher energy density and lower cost of batteries.
【０００３】しかしながら、ペースト式は多孔体への高
密度充填が可能であるものの、集電体として機能する多
孔体の細孔径が大きいために、多孔体と活物質との電気
的接触が不充分となり、集電効率が悪いという欠点があ
る。このため、高密度に充填した活物質の発電能力を十
分に引出し得ないという問題がある。However, although the paste type allows high-density filling of the porous body, the porous body functioning as a current collector has a large pore size, so that electrical contact between the porous body and the active material is insufficient. Therefore, there is a drawback that the current collection efficiency is poor. For this reason, there is a problem that the power generation capacity of the active material densely packed cannot be sufficiently drawn out.
【０００４】そこで、従来よりこのようなペースト式の
欠点を改善することを目的とし、水酸化ニッケルと水
酸化カドミウム又は水酸化コバルトを含む固溶体活物質
粉末の表面に水酸化コバルトの被覆層を形成する技術
（特開昭６２−２２２５６６号公報）や、水酸化ニッ
ケルの表面部に水酸化ニッケルと水酸化コバルトの固溶
体を形成する技術（特開平３−６２４５７号公報）、更
には前記特開昭６２−２２２５６６号公報に記載の技術
を一層改良した技術として、水酸化ニッケル表面に形
成されたコバルト化合物を含む被覆層の上に親水性有機
物膜を施す技術（特開平５−１５１９６２号公報）など
が提案されている。これらの技術を適用した場合、活物
質粒子相互間における導電性が向上するため、ニッケル
正極の性能を向上させることができる。Therefore, for the purpose of improving the drawbacks of the paste method, the coating layer of cobalt hydroxide is formed on the surface of the solid solution active material powder containing nickel hydroxide and cadmium hydroxide or cobalt hydroxide. (Japanese Patent Laid-Open No. 62-222566), a technique of forming a solid solution of nickel hydroxide and cobalt hydroxide on the surface of nickel hydroxide (Japanese Patent Laid-Open No. 3-62457), and the above-mentioned Japanese Patent Laid-Open No. As a technique further improved from the technique described in JP-A-62-222566, a technique of applying a hydrophilic organic substance film on a coating layer containing a cobalt compound formed on the surface of nickel hydroxide (JP-A-5-151962) and the like. Is proposed. When these techniques are applied, the conductivity between the active material particles is improved, so that the performance of the nickel positive electrode can be improved.
【０００５】[0005]
【発明が解決しようとする課題】ところが、上記の技術
では、次のような問題点が解決できていない。即ち、水
酸化ニッケル粒子表面に水酸化コバルトを配した場合、
この水酸化コバルトが活物質粒子相互間の導電性を向上
させるが、粒子表面の水酸化コバルトは、過放電時に水
酸化ニッケルの内部に拡散し、粒子表面の水酸化コバル
ト量が減少するという現象が生じる。このため、活物質
粒子の導電性が低下し、その利用率が低下し、特に過放
電時において十分な電池容量が取り出せなくなるという
問題がある。しかし、前記拡散を見込んで予め多量の水
酸化コバルトを粒子表面又は活物質全体に配する方法で
は、水酸化ニッケル量（活物質本体の量）の相対的減少
を招くため、エネルギー密度を十分に高めることができ
なくなる。However, the above-mentioned technique cannot solve the following problems. That is, when cobalt hydroxide is arranged on the surface of the nickel hydroxide particles,
This cobalt hydroxide improves the conductivity between the active material particles, but the cobalt hydroxide on the surface of the particles diffuses into the nickel hydroxide during overdischarge, and the amount of cobalt hydroxide on the surface of the particles decreases. Occurs. For this reason, there is a problem that the conductivity of the active material particles is lowered, the utilization rate thereof is lowered, and a sufficient battery capacity cannot be taken out especially during overdischarge. However, in the method of preliminarily disposing a large amount of cobalt hydroxide on the particle surface or the entire active material in consideration of the above diffusion, the amount of nickel hydroxide (the amount of the active material main body) is relatively decreased, so that the energy density is sufficiently increased. It cannot be increased.
【０００６】また、前記の技術は、被覆層の上に親水
性有機物膜を施すことによりコバルト種が電解液中へ散
逸するのを物理的に防止しようとする技術であるので、
この技術でも母粒子内部に拡散する現象を抑制できな
い。Further, the above-mentioned technique is a technique for physically preventing the cobalt species from being dissipated in the electrolytic solution by applying a hydrophilic organic substance film on the coating layer.
Even with this technique, the phenomenon of diffusion inside the mother particles cannot be suppressed.
【０００７】本発明は、前記従来技術における問題点を
解決するためになされたものであり、活物質粒子相互間
の導電性を少ない量のコバルト化合物でもって効果的に
向上させ、かつ過放電時においても母粒子表面近傍のコ
バルト化合物が水酸化ニッケル母粒子内部へ拡散するこ
とのないアルカリ蓄電池用正極活物質、及びそのような
アルカリ蓄電池用正極活物質の製造方法を提供すること
を目的とする。The present invention has been made in order to solve the above-mentioned problems in the prior art, and effectively improves the conductivity between the active material particles with a small amount of the cobalt compound, and during overdischarge. In order to provide a positive electrode active material for an alkaline storage battery in which the cobalt compound near the surface of the mother particle does not diffuse into the nickel hydroxide mother particle, and a method for producing such a positive electrode active material for an alkaline storage battery. .
【０００８】[0008]
【課題を解決するための手段】上記目的を達成するため
に、本発明は次の特徴を有している。請求項１記載の発
明は、少なくとも水酸化ニッケルと、コバルト化合物と
を含有する固溶体粒子を必須構成要素とするアルカリ蓄
電池用正極活物質であって、前記固溶体粒子は、粒子表
層に高く粒子中心部に向かって減少するコバルト濃度勾
配を有することを特徴とする。In order to achieve the above object, the present invention has the following features. The invention according to claim 1 is a positive electrode active material for an alkaline storage battery, which comprises solid solution particles containing at least nickel hydroxide and a cobalt compound as an essential constituent element, wherein the solid solution particles are high in the particle surface layer and the particle central portion. It is characterized by having a cobalt concentration gradient that decreases toward.
【０００９】請求項２記載の発明は、請求項１記載のア
ルカリ蓄電池用正極活物質において、前記固溶体粒子の
表面に粒子表層のコバルト濃度と同等以上のコバルト濃
度を有する水酸化コバルト被覆層が形成されていること
を特徴とする。According to a second aspect of the present invention, in the positive electrode active material for an alkaline storage battery according to the first aspect, a cobalt hydroxide coating layer having a cobalt concentration equal to or higher than that of the particle surface layer is formed on the surface of the solid solution particles. It is characterized by being.
【００１０】請求項３記載の発明は、前記水酸化コバル
ト被覆層中の水酸化コバルトが、被覆層の形成された固
溶体粒子をアルカリと酸素の共存下で加熱処理すること
によって、２価を超えるコバルト化合物としてあること
を特徴とする請求項２記載のアルカリ蓄電池用正極活物
質。According to the third aspect of the present invention, the cobalt hydroxide in the cobalt hydroxide coating layer has a valence of more than 2 by subjecting the solid solution particles having the coating layer formed thereon to heat treatment in the presence of alkali and oxygen. It is as a cobalt compound, The positive electrode active material for alkaline storage batteries of Claim 2 characterized by the above-mentioned.
【００１１】請求項４記載の発明は、請求項１記載のア
ルカリ蓄電池用正極活物質が、前記固溶体粒子と、前記
固溶体粒子表層のコバルト濃度と同等以上のコバルト濃
度を有する水酸化コバルト含有粉末とを含むことを特徴
とする。According to a fourth aspect of the present invention, the positive electrode active material for an alkaline storage battery according to the first aspect is the solid solution particles, and a cobalt hydroxide-containing powder having a cobalt concentration equal to or higher than the cobalt concentration of the surface layer of the solid solution particles. It is characterized by including.
【００１２】請求項５記載の発明は、請求項１ないし請
求項４記載のアルカリ蓄電池用正極活物質において、前
記固溶体粒子が、更に亜鉛化合物、カドミウム化合物、
マグネシウム化合物、マンガン化合物からなる群より選
択される１種以上の化合物を含有することを特徴とす
る。According to a fifth aspect of the present invention, in the positive electrode active material for alkaline storage batteries according to the first to fourth aspects, the solid solution particles are further a zinc compound, a cadmium compound,
It is characterized by containing one or more compounds selected from the group consisting of magnesium compounds and manganese compounds.
【００１３】請求項６記載の発明は、攪拌下ニッケル塩
溶液に対し、コバルト塩添加量が連続的または段階的に
増加するようにコバルト塩溶液を注加し、これと同時並
行的にアルカリ溶液を注加して反応溶液ｐＨを所定値に
維持することにより、粒子中心部で低く粒子表層に高い
コバルト濃度勾配を有するニッケル・コバルト固溶体粒
子を作製する固溶体粒子作製工程を備えるアルカリ蓄電
池用固溶体活物質粒子の製造方法であることを特徴とす
るAccording to a sixth aspect of the present invention, the cobalt salt solution is added to the nickel salt solution under stirring so that the amount of cobalt salt added increases continuously or stepwise, and at the same time, the alkali solution is added in parallel. Is added to maintain the pH of the reaction solution at a predetermined value, the solid solution active material for an alkaline storage battery is provided with a solid solution particle producing step of producing nickel-cobalt solid solution particles having a low cobalt concentration gradient and a high cobalt concentration gradient in the particle surface layer. Characterized by a method for producing material particles
【００１４】請求項７記載の発明は、請求項６記載のア
ルカリ蓄電池用固溶体活物質粒子の製造方法の固溶体粒
子作製工程において、反応溶液中にアンモニアを存在さ
せることを特徴とする。The invention according to claim 7 is characterized in that ammonia is present in the reaction solution in the solid solution particle producing step of the method for producing solid solution active material particles for an alkaline storage battery according to claim 6.
【００１５】請求項８記載の発明は、請求項６ないし請
求項７記載のアルカリ蓄電池用固溶体活物質粒子の製造
方法において、更に、前記ニッケル・コバルト固溶体粒
子を、少なくともコバルト塩を溶解したコバルト塩溶液
に攪拌分散し、この攪拌分散液にアルカリ溶液を注加し
分散液ｐＨを所定値に調整することによりコバルト化合
物を析出させ、前記ニッケル・コバルト固溶体粒子の表
面に水酸化コバルト被覆層を形成する被覆層形成工程を
備えることを特徴とする。According to an eighth aspect of the present invention, in the method for producing solid solution active material particles for an alkaline storage battery according to the sixth to seventh aspects, the nickel-cobalt solid solution particles are further prepared by dissolving at least a cobalt salt. The solution is stirred and dispersed in a solution, and an alkaline solution is added to this stirred dispersion to adjust the pH of the dispersion to a predetermined value, thereby precipitating a cobalt compound and forming a cobalt hydroxide coating layer on the surface of the nickel-cobalt solid solution particles. And a coating layer forming step.
【００１６】請求項９記載の発明は、請求項８記載のア
ルカリ蓄電池用固溶体活物質粒子の製造方法において、
更に、前記被覆層形成工程で作製した被覆固溶体粒子に
アルカリ金属溶液を含浸させた後、酸素存在下で熱処理
するアルカリ熱処理工程を備えることを特徴とする。The invention according to claim 9 is the method for producing solid solution active material particles for an alkaline storage battery according to claim 8,
Further, the method is characterized by further comprising an alkali heat treatment step of impregnating the coated solid solution particles produced in the coating layer forming step with an alkali metal solution, and then heat treating in the presence of oxygen.
【００１７】請求項１０記載の発明は、請求項９記載の
アルカリ蓄電池用固溶体活物質粒子の製造方法におい
て、前記アルカリ金属溶液が、水酸化カリウム溶液であ
ることを特徴とする。According to a tenth aspect of the invention, in the method for producing solid solution active material particles for an alkaline storage battery according to the ninth aspect, the alkali metal solution is a potassium hydroxide solution.
【００１８】請求項１１記載の発明は、請求項９ないし
請求項１０記載のアルカリ蓄電池用固溶体活物質粒子の
製造方法において、前記熱処理の温度が、４０〜１００
℃であることを特徴とする。According to an eleventh aspect of the present invention, in the method for producing solid solution active material particles for an alkaline storage battery according to the ninth to tenth aspects, the heat treatment temperature is 40 to 100.
It is characterized in that it is ℃.
【００１９】[0019]
【実施の形態】以下、本発明にかかるニッケル固溶体活
物質粒子の作製方法およびこの固溶体活物質粒子を用い
た正極の製造方法を説明し、その後この正極を組み込ん
だ電池により各種固溶体活物質粒子の電気化学的特性を
説明することにより、本発明の実施の形態を明らかにす
る。BEST MODE FOR CARRYING OUT THE INVENTION A method for producing nickel solid solution active material particles according to the present invention and a method for producing a positive electrode using the solid solution active material particles according to the present invention will be described below. The embodiments of the present invention will be clarified by explaining the electrochemical characteristics.
【００２０】〔各種固溶体活物質粒子の作製〕 （本発明活物質粒子Ａ0 の作製）先ず、固溶体粒子の全
重量を１００とするとき、亜鉛とコバルトの金属元素重
量分率がそれぞれ０．５重量％、２重量％となるよう
に、硫酸ニッケル水溶液（ａ液）、硫酸亜鉛水溶液（ｂ
液）、硫酸コバルト水溶液（ｃ液）を用意した。次に前
記ａ液とｂ液を攪拌混合し、このａｂ液に対し、攪拌混
合を続けながら、単位時間当たりの注加量が段階的又は
連続的に増加するように注加量を制御しながら前記ｃ液
を添加するとともに、これと同時並行的にａｂｃ反応溶
液のｐＨが所定値に維持されるようにアンモニア水およ
び水酸化ナトリウム水溶液を徐々に添加した。これによ
りａｂｃ反応溶液中に水酸化ニッケルを主成分とする活
物質粒子が生成・析出するので、これを採取し、水洗・
乾燥してニッケル・コバルト固溶体粒子を得た。以下、
このニッケル・コバルト固溶体粒子を本発明活物質粒子
Ａ0 とする。[Preparation of Various Solid Solution Active Material Particles] (Preparation of Active Material Particles A 0 of the Present Invention) First, assuming that the total weight of the solid solution particles is 100, the weight fractions of metal elements of zinc and cobalt are 0.5 and 0.5, respectively. Wt%, 2 wt% so that the nickel sulfate aqueous solution (a solution), zinc sulfate aqueous solution (b
Solution) and a cobalt sulfate aqueous solution (solution c) were prepared. Next, the a liquid and the b liquid are stirred and mixed, and while the ab liquid is continuously stirred and mixed, the pouring amount is controlled so that the pouring amount per unit time increases stepwise or continuously. While the above-mentioned liquid c was added, concurrently with this, aqueous ammonia and aqueous sodium hydroxide solution were gradually added so that the pH of the abc reaction solution was maintained at a predetermined value. As a result, active material particles containing nickel hydroxide as a main component are generated and precipitated in the abc reaction solution, and these are collected and washed with water.
It was dried to obtain nickel-cobalt solid solution particles. Less than,
The nickel-cobalt solid solution particles are referred to as active material particles A 0 of the present invention.
【００２１】上記のようにａｂ液に対するｃ液の注加量
を段階的または連続的に増加する方法で各溶液を反応さ
せた場合、ニッケル化合物、亜鉛化合物、コバルト化合
物の３成分からなる固溶体粒子が得られ、この固溶体粒
子は、コバルト化合物が粒子内部で低く粒子表面で高い
濃度勾配（以下、Ｃｏ濃度勾配という）をもって粒子内
に分散したものとなる。When each solution is reacted by the method of increasing the pouring amount of the liquid c with respect to the liquid ab as described above stepwise or continuously, solid solution particles consisting of three components of nickel compound, zinc compound and cobalt compound The solid solution particles are obtained by dispersing the cobalt compound in the particles with a low concentration inside the particles and a high concentration gradient on the surface of the particles (hereinafter referred to as Co concentration gradient).
【００２２】なお、上記ａ、ｂ、ｃの各液の濃度および
使用量は、反応条件等を勘案して適宜可変するのがよい
が、例えば、ａ、ｂ、ｃ各液の濃度を２０重量％とし、
この濃度の各液を重量比でａ：ｂ：ｃ＝５０００：４
２．２：１６８．５の比率で用いた場合、上記した金属
元素重量分率の固溶体粒子が得られる。上記ではこの方
法に従って固溶体粒子を作成した。The concentration and the amount of each of the liquids a, b and c may be appropriately changed in consideration of the reaction conditions and the like. For example, the concentration of each liquid a, b and c is 20% by weight. %age,
The weight ratio of each liquid having this concentration was a: b: c = 5000: 4.
When used in a ratio of 2.2: 168.5, solid solution particles having the above-mentioned metal element weight fraction can be obtained. In the above, solid solution particles were prepared according to this method.
【００２３】また、ｃ液の注加方法の具体例としては、
例えばｃ液の全注加液量を１００とした場合、１回目に
その１／１００、２回目に３／１００、３回目に５／１
００、４回目に７／１００、５回目に９／１００、６回
目に１１／１００、７回目に１３／１００、８回目に１
５／１００、９回目に１７／１００、１０回目に１９／
１００というふうに段階的に注加液量を増大させる方法
や、高濃度のコバルト塩溶液と低濃度のコバルト塩溶液
を用意し、両溶液の混合比率を段階的または連続的に変
化させることにより、注加液のコバルト塩濃度を段階的
または連続的に高めていく方法が挙げられる。Further, as a specific example of the method of adding the liquid c,
For example, if the total amount of c-solution added is 100, then 1/100 of that is the first time, 3/100 is the second time, and 5/1 is the third time.
00, 4th 7/100, 5th 9/100, 6th 11/100, 7th 13/100, 8th 1
5/100, 9/17/100, 10/19 /
By gradually increasing the amount of liquid to be added, such as 100, or by preparing a high-concentration cobalt salt solution and a low-concentration cobalt salt solution, and changing the mixing ratio of both solutions stepwise or continuously. , A method of increasing the cobalt salt concentration of the injection liquid stepwise or continuously.
【００２４】更に、上記反応溶液のｐＨは１０〜１２の
範囲で適当に調整すればよいが、反応収率や粒子性状の
面から好ましくはｐＨ１１とするのがよい。また、反応
溶液のｐＨ調整用のアルカリは特に限定されるものでは
なく、例えば水酸化ナトリウム水溶液のみで行うことも
できるが、良好な粒状固溶体を得やすいことから、好ま
しくはアンモニア水溶液と水酸化ナトリウム水溶液とを
併用するのがよい。更にアンモニアと水酸化ナトリウム
の使用比率としては、１：０．０５〜１００（モル比）
の範囲がよく、好ましくは１：２〜３とするのがよい。Further, the pH of the reaction solution may be appropriately adjusted within the range of 10 to 12, but pH 11 is preferable from the viewpoint of reaction yield and particle properties. Further, the alkali for adjusting the pH of the reaction solution is not particularly limited, and it can be carried out, for example, only with an aqueous solution of sodium hydroxide, but it is preferable to use an aqueous ammonia solution and sodium hydroxide since it is easy to obtain a good granular solid solution. It is recommended to use it together with an aqueous solution. Furthermore, the usage ratio of ammonia and sodium hydroxide is 1: 0.05 to 100 (molar ratio)
The range is good, preferably 1: 2 to 3.
【００２５】（本発明被覆活物質粒子BＡ0 の作製）上
記本発明活物質粒子Ａ0 を約２倍量の硫酸コバルト水溶
液（濃度；１０重量％）の中に入れ、攪拌下、水酸化ナ
トリウム水溶液を反応液ｐＨが１０に維持されるように
徐々に添加する。これにより活物質粒子Ａ0 の周囲に水
酸化コバルトが析出し、粒子の表面が水酸化コバルトで
被覆されるので、硫酸コバルト水溶液の添加量を調整し
て、１０重量％（被覆粒子に対する値）の水酸化コバル
トを被覆した。この被覆粒子を補集し水洗・乾燥した。
以下、この被覆粒子を本発明被覆活物質粒子BＡ0 とす
る。(Preparation of the coated active material particles BA 0 of the present invention) The active material particles A 0 of the present invention were placed in about twice the amount of an aqueous cobalt sulfate solution (concentration: 10% by weight), and sodium hydroxide was added with stirring. The aqueous solution is slowly added so that the reaction pH is maintained at 10. As a result, cobalt hydroxide is deposited around the active material particles A 0 and the surface of the particles is coated with cobalt hydroxide. Therefore, the amount of the cobalt sulfate aqueous solution added is adjusted to be 10% by weight (value for the coated particles). Coated with cobalt hydroxide. The coated particles were collected, washed with water and dried.
Hereinafter, the coated particles are referred to as the coated active material particles BA 0 of the present invention.
【００２６】（比較活物質粒子Ｘの作製）上記本発明活
物質粒子Ａ0 の作製の場合と同様に、固溶体粒子の全重
量を１００とするとき、亜鉛とコバルトの金属元素重量
分率がそれぞれ０．５重量％、２重量％となるように、
硫酸ニッケル水溶液（ａ液）、硫酸亜鉛水溶液（ｂ
液）、硫酸コバルト水溶液（ｃ液）を用意した。次にａ
液、ｂ液及びｃ液を混合し、攪拌下この混合液に、反応
溶液のｐＨが１１に維持されるようにアンモニア水およ
び水酸化ナトリウム水溶液を徐々に添加した。これによ
り反応溶液中に水酸化ニッケルを主成分とする固溶体粒
子が生成・析出するので、これを補集し、水洗・乾燥し
た。以下、この固溶体粒子を比較活物質粒子Ｘとする。(Preparation of Comparative Active Material Particles X) Similar to the preparation of the active material particles A 0 of the present invention, assuming that the total weight of the solid solution particles is 100, the weight fractions of metallic elements of zinc and cobalt are respectively. 0.5% by weight, 2% by weight,
Nickel sulfate aqueous solution (a liquid), zinc sulfate aqueous solution (b
Solution) and a cobalt sulfate aqueous solution (solution c) were prepared. Then a
Liquid, liquid b and liquid c were mixed, and aqueous ammonia and aqueous sodium hydroxide solution were gradually added to this mixed liquid with stirring so that the pH of the reaction solution was maintained at 11. As a result, solid solution particles containing nickel hydroxide as a main component are generated and deposited in the reaction solution. These particles were collected, washed with water and dried. Hereinafter, the solid solution particles are referred to as comparative active material particles X.
【００２７】なお、この比較活物質粒子Ｘと本発明活物
質粒子Ａ0 とは、粒子内のコバルト化合物の分布状態が
異なり、比較活物質粒子Ｘではコバルト化合物が粒子内
にほぼ均一に分布している。The comparative active material particles X and the active material particles A 0 of the present invention differ in the distribution state of the cobalt compound in the particles, and in the comparative active material particles X, the cobalt compound is distributed almost uniformly in the particles. ing.
【００２８】（比較被覆活物質粒子BＸの作製）比較活
物質粒子Ｘを用いたこと以外は、本発明活物質粒子BＡ
0 の作製の場合と同様にして、Ｘ粒子の表面に水酸化コ
バルト被覆層を形成した。この粒子を比較被覆活物質粒
子BＸとする。(Preparation of Comparative Coated Active Material Particles BX) Except that the comparative active material particles X were used, the active material particles BA of the present invention were prepared.
A cobalt hydroxide coating layer was formed on the surface of the X particles in the same manner as in the case of manufacturing 0 . These particles are referred to as comparative coated active material particles BX.
【００２９】〔各種正極の作製〕 （本発明例正極ＥＡ0 の作製）本発明活物質粒子Ａ0 を
９０重量部と、水酸化コバルト粉末（平均粒径；０．２
０μｍ）を１０重量部と、酸化亜鉛粉末（平均粒径；
０．６５μｍ）を２重量部とを混合し、これに０．２重
量％ヒドロキシプロピルセルロース水溶液を５０重量部
を加えて混練して活物質スラリーを調製した。この活物
質スラリーを発泡ニッケル体（多孔度９５％、厚み約
１．６ｍｍ）に充填し乾燥した後、圧延して厚み０．６
ｍｍのニッケル正極を作製した。このニッケル正極を、
本発明例正極ＥＡ0 とする。[Preparation of Various Positive Electrodes] (Preparation of Inventive Example Positive Electrode EA 0 ) 90 parts by weight of the active material particles A 0 of the present invention and cobalt hydroxide powder (average particle size; 0.2)
0 μm) and 10 parts by weight of zinc oxide powder (average particle size;
0.65 μm) was mixed with 2 parts by weight, and 50 parts by weight of a 0.2% by weight hydroxypropylcellulose aqueous solution was added and kneaded to prepare an active material slurry. A foamed nickel body (porosity 95%, thickness about 1.6 mm) was filled with this active material slurry, dried, and then rolled to a thickness of 0.6.
mm nickel positive electrode was prepared. This nickel positive electrode
The present invention example positive electrode EA 0 .
【００３０】この本発明例正極ＥＡ0 は、別途添加した
水酸化コバルト含有粉末（水酸化コバルト粉末、酸化亜
鉛粉末）が、前記本発明活物質粒子Ａ0 の近傍に存在す
る状態で正極が構成されている点に特徴を有する。This positive electrode EA 0 of the present invention is constructed such that a separately added cobalt hydroxide-containing powder (cobalt hydroxide powder, zinc oxide powder) is present in the vicinity of the active material particles A 0 of the present invention. It is characterized by the fact that it is.
【００３１】なお、上記本発明例正極ＥＡ0 では、水酸
化コバルト粉末と酸化亜鉛粉末とからなる水酸化コバル
ト含有粉末を用いたが、例えば酸化亜鉛以外の他の第三
の成分（後記）と水酸化コバルトとの混合末を水酸化コ
バルト含有粉末として用いることもできるし、水酸化コ
バルトのみからなる粉末を水酸化コバルト含有粉末とし
て用いることもできる。即ち、本明細書における「水酸
化コバルト含有粉末」は、「少なくとも水酸化コバルト
を含有した粉末」の意味で使用されている。In the present invention positive electrode EA 0 , a cobalt hydroxide-containing powder composed of cobalt hydroxide powder and zinc oxide powder was used. For example, a third component other than zinc oxide (described later) was used. The mixed powder with cobalt hydroxide can be used as the cobalt hydroxide-containing powder, or the powder consisting of cobalt hydroxide alone can be used as the cobalt hydroxide-containing powder. That is, the "cobalt hydroxide-containing powder" in the present specification is used to mean "powder containing at least cobalt hydroxide".
【００３２】（本発明例正極ＥBＡ0 の作製）前記本発
明被覆活物質粒子BＡ0 を用いたこと以外は、上記本発
明例正極ＥＡ0 の作製と同様にして、本発明例正極ＥBＡ
0 を作製した。(Invention Example Positive Electrode EBA0Of the above)
Bright coated active material particles BA0Except for using
Clear positive electrode EA0 In the same manner as in the preparation of
0Was prepared.
【００３３】この本発明例正極ＥBＡ0 と前記正極ＥＡ
0 とは、組成的には同一であるが、次の点で異なる。即
ち、正極ＥＡ0 では固溶体粒子Ａ0 と共に１０重量％の
水酸化コバルトが粉末で添加されているのに対し、正極
ＥBＡ0 では、１０重量％の水酸化コバルトが固溶体粒
子Ａ0 の表面に被覆された状態となっている。The positive electrode EBA 0 of the present invention and the positive electrode EA
The composition is the same as 0 , but is different in the following points. That is, in the positive electrode EA 0 , 10% by weight of cobalt hydroxide was added as a powder together with the solid solution particles A 0 , whereas in the positive electrode EBA 0 , 10% by weight of cobalt hydroxide was coated on the surface of the solid solution particles A 0. It is in the state of being
【００３４】（比較例電極ＥＸの作製）前記比較活物質
Ｘを用いたこと以外は、上記本発明例正極ＥＡ0 の作製
と同様にして、比較例電極ＥＸを作製した。(Production of Comparative Example Electrode EX) A comparative example electrode EX was produced in the same manner as in the production of the positive electrode EA 0 of the present invention except that the comparative active material X was used.
【００３５】（比較例電極ＥBＸの作製）前記比較活物
質粒子BＸを用いたこと以外は、上記本発明例正極ＥＡ
0 の作製と同様にして、比較例電極ＥBＸを作製した。(Preparation of Comparative Example Electrode EBX) Except that the comparative active material particles BX were used, the positive electrode EA of the present invention was used.
A comparative electrode EBX was prepared in the same manner as the preparation of 0 .
【００３６】なお、上記において、「Ｅ」は電極を意味
し、例えば「ＥＡ0 」は本発明活物質粒子Ａ0 を用いた
電極（正極）であることを意味する。また、「B 」は、
水酸化コバルトが粒子表面に被覆されたものであること
を意味し、例えば「BＡ0 」は本発明活物質粒子Ａ0 を
母粒子としこの表面に水酸化コバルト被覆層が形成され
た活物質であることを意味する。本明細書では全てこの
用法に従って活物質、正極の種類の別が表記してある。In the above, "E" means an electrode, for example "EA 0 " means an electrode (positive electrode) using the active material particles A 0 of the present invention. Also, "B" is
This means that the surface of the particles is coated with cobalt hydroxide. For example, “BA 0 ” is an active material having the active material particles A 0 of the present invention as a mother particle and a cobalt hydroxide coating layer formed on the surface thereof. Means there is. In this specification, the types of active materials and positive electrodes are all described according to this usage.
【００３７】〔電気化学的特性の測定・評価〕上記で作
製した各種正極を用いて以下に記載した簡易セルとニッ
ケル水素蓄電池を構成し、これら電池を用いて各種正極
活物質の単位活物質重量当たりの放電容量と過放電特性
を調べた。[Measurement / Evaluation of Electrochemical Properties] A simple cell and a nickel-hydrogen storage battery described below are constructed by using the various positive electrodes prepared above, and the unit active material weight of various positive electrode active materials is formed using these batteries. The discharge capacity per unit and the overdischarge characteristics were investigated.
【００３８】（簡易セル）上記各種正極とこの正極より
も十分に大きな容量を有する公知の焼結式カドミウム負
極とを、不織布からなるセパレータを介して重ね、その
両側を内側に加重が掛かる状態にアクリル板で挟み一対
の電極体となす。この電極体を電気化学的に過剰量の水
酸化カリウム水溶液（濃度；約２５重量％）中に浸漬
し、理論容量３６０ｍＡｈの開放型簡易セルを構成し
た。(Simple Cell) The above-mentioned various positive electrodes and a known sintered cadmium negative electrode having a capacity sufficiently larger than this positive electrode are overlapped with a separator made of a non-woven fabric, and both sides thereof are put in a state in which a weight is applied to the inside. It is sandwiched between acrylic plates to form a pair of electrodes. This electrode body was electrochemically immersed in an excessive amount of an aqueous potassium hydroxide solution (concentration: about 25% by weight) to form an open type simple cell having a theoretical capacity of 360 mAh.
【００３９】（ニッケル水素蓄電池）上記各種正極とこ
の正極よりも容量の大きい下記の水素吸蔵合金負極と
を、不織布からなるセパレータを介して巻回し電極体を
作製する。この電極体を電池缶に挿入し、更に７〜８．
５規定の水酸化カリウム水溶液を注入した後、電池缶開
口部を密閉して、理論容量１２００ｍＡｈの密閉型ニッ
ケル・水素蓄電池を構成した。(Nickel Hydrogen Storage Battery) The above various positive electrodes and the following hydrogen storage alloy negative electrode having a larger capacity than this positive electrode are wound around a separator made of non-woven fabric to form an electrode assembly. This electrode body was inserted into a battery can, and further 7-8.
After injecting a 5 N aqueous potassium hydroxide solution, the opening of the battery can was closed to form a sealed nickel-hydrogen storage battery having a theoretical capacity of 1200 mAh.
【００４０】水素吸蔵合金負極の作製方法は次の通りで
ある。Ｍｍ、Ｎｉ、Ｃｏ、Ａｌ、Ｍｎの各金属元素（市
販品）を化学量論比で１：３．４：０．８：０．２：
０．６となるように秤量して高周波溶解炉に入れ、混合
溶融して水素吸蔵合金鋳塊となし、この合金鋳塊を粗粉
砕し更に平均粒径１５０μｍ前後まで機械的粉砕した。
次いで、この合金粉末にポリエチレンオキサイド（結着
剤）と水を適量加えて混練して活物質スラリーとなし、
このスラリーをパンチングメタルからなる集電体の両面
に塗布・乾燥した後、プレスして厚み約０．４ｍｍの水
素吸蔵合金負極を作製した。なお、酸化を防止するた
め、合金の鋳造、粉砕は不活性ガス雰囲気下で行った。The method for producing the hydrogen storage alloy negative electrode is as follows. The stoichiometric ratio of each metal element of Mm, Ni, Co, Al, and Mn (commercial item) is 1: 3.4: 0.8: 0.2:
It was weighed so as to be 0.6 and put in a high frequency melting furnace, mixed and melted to form a hydrogen storage alloy ingot, and this alloy ingot was coarsely crushed and mechanically crushed to an average particle size of about 150 μm.
Next, an appropriate amount of polyethylene oxide (binder) and water are added to this alloy powder and kneaded to form an active material slurry,
This slurry was applied on both sides of a current collector made of punched metal, dried, and then pressed to produce a hydrogen storage alloy negative electrode having a thickness of about 0.4 mm. In order to prevent oxidation, the alloy was cast and crushed in an inert gas atmosphere.
【００４１】（電気化学的特性の測定条件）単位活物質
重量当たりの放電容量は、簡易セルを０．１Ｃ（３６ｍ
Ａ）の電流値で２４時間充電した後、１／３Ｃ（１２０
ｍＡ）の電流値で電池電圧が１．０Ｖに達するまで放電
してこの時の放電容量を測定し、下記数１に従って算出
した。(Conditions for Measuring Electrochemical Properties) The discharge capacity per unit weight of the active material was 0.1 C (36 m) for the simple cell.
After charging for 24 hours with the current value of A), 1 / 3C (120
The battery was discharged at a current value of mA) until the battery voltage reached 1.0 V, and the discharge capacity at this time was measured and calculated according to the following formula 1.
【００４２】[0042]
【数１】 [Equation 1]
【００４３】過放電特性は、先ず前記密閉型ニッケル・
水素蓄電池に対し、０．１Ｃ（１２０ｍＡ）の電流値で
１６時間充電し、０．２Ｃ（２４０ｍＡ）の電流値で電
池電圧が１．０Ｖに達するまで放電するというサイクル
を３サイクル繰り返して蓄電池の活性化を行い、この活
性化済蓄電池に対し下記条件で充放電を行い、下記数２
で過放電特性値を求める方法によった。The overdischarge characteristics are as follows.
A hydrogen storage battery is charged at a current value of 0.1 C (120 mA) for 16 hours, and then discharged at a current value of 0.2 C (240 mA) until the battery voltage reaches 1.0 V. This cycle is repeated 3 times, After activation, charge and discharge this activated storage battery under the following conditions,
The method of obtaining the over-discharge characteristic value by
【００４４】１）１Ｃ（１２００ｍＡ）の電流値で、電
池電圧がピークに達し、ピーク電圧値からの電圧降下量
（−ΔＶ値）が１０ｍＶに達するまで充電を行う。 ２）１時間の休止の後、１Ｃの電流値で電池電圧が１．
０Ｖに達するまで放電を行う。ここでこの時の放電容量
Ｗi（初回値）を測定しておく。 ３）引き続いて０．０５Ｃ（６０ｍＡ）の電流値で１６
時間の強制放電を行う。 ４）上記１）〜３）の操作を５サイクル繰り返し、５サ
イクル目の放電容量Ｗf を測定する。1) At a current value of 1 C (1200 mA), charging is performed until the battery voltage reaches a peak and the voltage drop amount (-ΔV value) from the peak voltage value reaches 10 mV. 2) After a 1-hour rest, the battery voltage was 1.
Discharge until it reaches 0V. Here, the discharge capacity Wi (initial value) at this time is measured. 3) Continue to 16 at the current value of 0.05C (60mA)
Perform a forced discharge of time. 4) The above operations 1) to 3) are repeated for 5 cycles, and the discharge capacity Wf at the 5th cycle is measured.
【００４５】[0045]
【数２】 [Equation 2]
【００４６】（測定結果）表１に、上記で作製した各種
固溶体粒子の組成及び特徴の一覧を示す。また表２に、
これらの固溶体粒子を用いて作製した各種電極の主要成
分の組成を示すとともに併せて電気化学的特性に関する
試験結果を示す。(Measurement Results) Table 1 shows a list of the composition and characteristics of the various solid solution particles produced above. Also in Table 2,
The compositions of the main components of various electrodes produced using these solid solution particles are shown, and also the test results concerning the electrochemical characteristics are shown.
【００４７】[0047]
【表１】 [Table 1]
【００４８】[0048]
【表２】 [Table 2]
【００４９】表２の正極ＥＡ0 とＥＸの結果において、
本発明活物質粒子Ａ0 を用いた正極ＥＡ0 は、比較活物
質粒子Ｘを用いた正極ＥＸに比較し、顕著に高い過放電
特性値を示した。ここで、正極ＥＡ0 と正極ＥＸとは固
溶体粒子の作製方法（Ｃｏ濃度勾配の有無）のみが異な
る。したがって、両正極の過放電特性の差は、Ｃｏ濃度
勾配の有無に原因することは明らかであり、このことか
ら、水酸化ニッケルとコバルト化合物を含む固溶体粒子
において、粒子中心部に低く粒子表層に高いＣｏ濃度勾
配を形成してやると、過放電特性が顕著に高まることが
判る。In the results of the positive electrodes EA 0 and EX in Table 2,
The positive electrode EA 0 using the active material particles A 0 of the present invention showed a remarkably high overdischarge characteristic value as compared with the positive electrode EX using the comparative active material particles X. Here, the positive electrode EA 0 and the positive electrode EX differ only in the method of producing solid solution particles (presence or absence of a Co concentration gradient). Therefore, it is clear that the difference in the overdischarge characteristics of the two positive electrodes is due to the presence or absence of a Co concentration gradient, and from this, in the solid solution particles containing nickel hydroxide and a cobalt compound, it is low in the particle central portion and in the particle surface layer. It can be seen that when a high Co concentration gradient is formed, the overdischarge characteristic is significantly improved.
【００５０】ところで、コバルト化合物を濃度勾配をも
って固溶体粒子に分散させると過放電特性が向上する理
由は、次のように考えられる。正極内に形成される導電
ネットワークは、活物質同志の接触によるものである。
しかし、活物質粒子の導電性を高めるために、大量のコ
バルト化合物を配合した場合、粒子の水酸化ニッケル
（活物質本体）の密度が低下しエネルギー密度の低下を
招く。したがって、導電性改善の目的で配合するコバル
ト化合物は可能な限り少量の方が好ましく、このために
は、コバルト化合物を粒子表面にのみ存在させるのがよ
い。The reason why the overdischarge characteristics are improved by dispersing the cobalt compound in the solid solution particles with a concentration gradient is considered as follows. The conductive network formed in the positive electrode is due to the contact between the active materials.
However, when a large amount of a cobalt compound is mixed in order to increase the conductivity of the active material particles, the density of nickel hydroxide (active material main body) of the particles is reduced, resulting in a decrease in energy density. Therefore, it is preferable that the amount of the cobalt compound blended for the purpose of improving the conductivity is as small as possible, and for this purpose, the cobalt compound should be present only on the particle surface.
【００５１】しかし、粒子表面にのみコバルト化合物を
存在させた場合、固溶体活物質粒子では、過放電時に粒
子表面のコバルト化合物が粒子内部に拡散し、Ｃｏ濃度
が低下する。これに対し、粒子中心部に低く粒子表面に
高いＣｏ濃度勾配を有する固溶体活物質粒子では、粒子
表層とその直近内側とのコバルト濃度差が小さいため、
コバルトの粒子内部への浸透・拡散が抑制される。ま
た、別途添加され粒子近傍に存在する水酸化コバルト粉
末と粒子表面とのコバルト濃度差も小さくできるので、
粒子表面近傍に常に高濃度のコバルト化合物を存在させ
ることができる。However, when the cobalt compound is allowed to exist only on the surface of the particles, in the solid solution active material particles, the cobalt compound on the surface of the particles diffuses inside the particles at the time of overdischarge, and the Co concentration decreases. On the other hand, in the solid solution active material particles having a low Co concentration gradient on the particle surface which is low in the center of the particle, the difference in cobalt concentration between the particle surface layer and the immediate inner side thereof is small,
The penetration and diffusion of cobalt into the particles is suppressed. Further, since the cobalt concentration difference between the cobalt hydroxide powder which is separately added and exists near the particles and the particle surface can be reduced,
A high concentration of cobalt compound can always be present near the surface of the particles.
【００５２】つまり、Ｃｏ濃度勾配を有する固溶体活物
質粒子を用い構成された正極では、水酸化コバルトを介
して形成される粒子相互間導電ネットワークが、過放電
時においても良好な導電性を維持する。よって、従来の
固溶体活物質粒子を用いた正極に比べ、過放電特性が顕
著に向上する。That is, in the positive electrode constituted by using the solid solution active material particles having a Co concentration gradient, the interparticle conductive network formed via cobalt hydroxide maintains good conductivity even during overdischarge. . Therefore, the overdischarge characteristics are remarkably improved as compared with the positive electrode using the conventional solid solution active material particles.
【００５３】なお、後記するが、固溶体粒子中に配合さ
れた亜鉛化合物等の第三の成分も、過放電時におけるコ
バルトの拡散を抑制するように作用する。したがって、
本発明固溶体活物質粒子では、Ｃｏ濃度勾配の作用と第
三の成分の作用とが合わさって一層良好な過放電特性が
得られる。このことからして、この亜鉛化合物をコバル
ト化合物と同様な方法により濃度勾配を持たせて粒子中
に分布させるのも好ましい。As will be described later, the third component such as the zinc compound mixed in the solid solution particles also acts to suppress the diffusion of cobalt during overdischarge. Therefore,
In the solid solution active material particles of the present invention, the action of the Co concentration gradient and the action of the third component are combined to obtain better overdischarge characteristics. From this, it is also preferable that the zinc compound be distributed in the particles with a concentration gradient by the same method as the cobalt compound.
【００５４】次に正極ＥＡ0 、ＥＸと正極ＥBＡ0 、ＥB
Ｘの結果を比較検討する。表２において、正極ＥＡ
0 は、被覆固溶体粒子を用いた正極ＥBＡ0 に比べ、過
放電特性値がやや低下したものの、単位活物質重量当た
りの放電容量がやや向上した。この傾向はＥＸとＥBＸ
との間でも同様であった。Next, the positive electrodes EA 0 and EX and the positive electrodes EBA 0 and EB
Weigh the results of X. In Table 2, the positive electrode EA
Compared with the positive electrode EBA 0 using the coated solid solution particles, 0 had a slightly lower overdischarge characteristic value, but the discharge capacity per unit active material weight was slightly improved. This tendency is EX and EBX
It was the same between and.
【００５５】ここで、正極ＥＡ0 及びＥＸと、正極ＥB
Ａ0 及びＥBＸとは被覆層の有無のみが異なり、前者
は、水酸化コバルトを粉末で添加したものであり、後者
は前者と同一量の水酸化コバルトを固溶体粒子表面に被
覆したものである。よって、単に固溶体粒子表面に水酸
化コバルトを被覆しただけでは、被覆効果が十分に現れ
ないことが判る。そこで、この結果を踏まえ、以下では
水酸化ニッケル、コバルト化合物以外の亜鉛化合物等の
第三の成分の影響、並びに水酸化コバルト被覆層の処理
条件と電気化学的特性の関係を調べ、Ｃｏ濃度勾配を有
する固溶体粒子の電気化学的特性を更に向上させ得る条
件を確立した。以下、検討内容を順次説明する。Here, the positive electrodes EA 0 and EX and the positive electrode EB
Only the presence or absence of a coating layer is different from A 0 and EBX, the former is one in which cobalt hydroxide is added as a powder, and the latter is one in which the same amount of cobalt hydroxide as the former is coated on the surface of the solid solution particles. Therefore, it is understood that the coating effect is not sufficiently exhibited only by coating the surface of the solid solution particles with cobalt hydroxide. Therefore, based on these results, in the following, the effect of the third component such as nickel hydroxide and a zinc compound other than the cobalt compound, and the relationship between the treatment conditions of the cobalt hydroxide coating layer and the electrochemical characteristics are investigated, and the Co concentration gradient is investigated. The conditions that can further improve the electrochemical characteristics of the solid solution particles having The details of the study will be described below.
【００５６】〔第三の成分の影響〕第三の成分として亜
鉛化合物、カドミウム化合物、マグネシウム化合物、マ
ンガン化合物からなる群より選択される化合物を使用
し、これらの化合物の１つと水酸化ニッケル及びコバル
ト化合物とで固溶体粒子（正極活物質粒子Ａ1 〜Ａ4）
を作製した。作製方法は第三の成分の種類及び配合割合
を変化させたこと以外、前記本発明活物質Ａ0 と同様で
あり、電気化学的特性試験の方法についても前記と同様
に行った。[Influence of Third Component] As the third component, a compound selected from the group consisting of a zinc compound, a cadmium compound, a magnesium compound and a manganese compound is used, and one of these compounds and nickel hydroxide and cobalt are used. Solid solution particles with compounds (positive electrode active material particles A 1 to A 4 )
Was produced. The production method was the same as that of the active material A 0 of the present invention except that the type and blending ratio of the third component were changed, and the electrochemical characteristic test method was also performed as described above.
【００５７】表３に、第三成分の種類を変えた正極活物
質粒子Ａ1 〜Ａ4 の組成を示す。また表４に、正極活物
質粒子Ａ1 〜Ａ4 をそれぞれ用いて前記本発明例正極Ｅ
Ａ0と同様にして作製した正極ＥＡ1 〜ＥＡ4 の主要成
分の組成、及び電気化学的特性試験の結果を示す。Table 3 shows the composition of the positive electrode active material particles A 1 to A 4 in which the kind of the third component is changed. Further, in Table 4, the positive electrode active material particles A 1 to A 4 are used, and the positive electrode E of the present invention is used.
The composition of the main components of the positive electrodes EA 1 to EA 4 produced in the same manner as A 0 and the result of the electrochemical characteristic test are shown.
【００５８】[0058]
【表３】 [Table 3]
【００５９】[0059]
【表４】 [Table 4]
【００６０】表４において、正極ＥＡ1 〜ＥＡ4 の単位
活物質重量当たりの放電容量および過放電特性値に大き
な差が認められなかった。他方、ＥＡ1 〜ＥＡ4 の特性
値を前記ＥＡ0 （表２参照）と比較において、単位活物
質重量当たりの放電容量は僅かに低下したものの、過放
電特性値は前記ＥＡ0 に比較し明確に向上していた。In Table 4, no significant difference was observed in the discharge capacity per unit weight of the positive electrode EA 1 to EA 4 and the overdischarge characteristic value. On the other hand, in comparing the characteristic values of EA 1 to EA 4 with EA 0 (see Table 2), the discharge capacity per unit weight of the active material was slightly decreased, but the overdischarge characteristic value was clearer than that of EA 0. Had improved.
【００６１】ここで、ＥＡ1 〜ＥＡ4 と前記ＥＡ0 の違
いは、第三成分の配合量のみであるので、上記結果は第
三成分量の増加に起因することは明白である。一方、表
２の結果と表４の結果から、各固溶体粒子の過放電特性
は、固溶体粒子Ｘ＜固溶体粒子Ａ0 ＜固溶体粒子Ａ1 〜
Ａ4 の順に向上していることが判る。更に本発明者ら
は、コバルト化合物とともに亜鉛化合物等の第三成分を
配合すると、亜鉛化合物等の第三成分が固溶体結晶組織
をコバルトの移動しにくい構造とすることを別途見いだ
している。これらの知見から、次のことが結論できる。Here, since the difference between EA 1 to EA 4 and EA 0 is only the amount of the third component blended, it is clear that the above result is due to the increase of the third component amount. On the other hand, from the results of Table 2 and Table 4, the overdischarge characteristics of each solid solution particle are as follows: solid solution particle X <solid solution particle A 0 <solid solution particle A 1
It can be seen that the improvement in the order of A 4. Furthermore, the present inventors have separately found that when a third component such as a zinc compound is blended with the cobalt compound, the third component such as the zinc compound causes the solid solution crystal structure to have a structure in which cobalt does not easily move. From these findings, the following can be concluded.
【００６２】即ち、亜鉛等の第三成分は、ニッケル・コ
バルト固溶体結晶組織をコバルトの移動しにくい構造と
するプラス作用がある一方、固溶体の水酸化ニッケル密
度を低下させ、単位活物質重量当たりの放電容量を低下
させるというマイナス作用もある。したがって、Ａ
0 （０．５wt％）よりも第三成分の添加量が多いＡ1 〜
Ａ 4 （２wt％）は、第三成分のマイナス作用がある程度
現れ、僅かに単位活物質重量当たりの放電容量が低下し
たものの、第三成分のプラス作用によりＡ1 〜Ａ4では
過放電特性が顕著に向上したものと考えられる。このこ
とから、亜鉛等の第三成分の作用を都合良く発揮させる
ためには、第三成分の配合量を適正にする必要がある
が、亜鉛化合物等の第三成分量を２％（金属元素重量％
表示）とした場合には、単位活物質重量当たりの放電容
量を殆ど低下させることなく、Ｃｏ濃度勾配の作用との
共働作用により過放電時におけるコバルト化合物の固溶
体内移動を有効に抑制することができる。That is, the third component such as zinc is nickel-cobalt.
Baltic solid solution crystal structure with a structure in which cobalt does not easily move
While it has a positive effect on
Decrease the discharge capacity per unit weight of the active material.
There is also a negative effect of allowing it. Therefore, A
0The amount of addition of the third component is larger than (0.5 wt%) A1~
A Four(2wt%) has some negative effect of the third component
The discharge capacity per unit weight of the active material is slightly reduced.
However, due to the positive action of the third component, A1~ AFourThen
It is considered that the over-discharge characteristics are remarkably improved. this child
Therefore, the action of the third component such as zinc is conveniently exhibited.
In order to do so, it is necessary to make the blending amount of the third component appropriate
However, the amount of the third component such as zinc compound is 2% (metal element weight%
Indication), discharge capacity per unit weight of active material
With the effect of the Co concentration gradient with almost no decrease in the amount.
Solid solution of cobalt compound during overdischarge by synergistic action
It is possible to effectively suppress the movement within the body.
【００６３】〔水酸化コバルト被覆層の処理条件〕被覆
固溶体粒子（BＡ0 ）に以下の条件でアルカリ熱処理を
実施して、一層電気化学的特性を高め得る条件を検討し
た。[Treatment Conditions for Cobalt Hydroxide Coating Layer] The coated solid solution particles (BA 0 ) were subjected to alkaline heat treatment under the following conditions, and conditions under which electrochemical characteristics could be further improved were examined.
【００６４】（アルカリ熱処理条件）前記被覆活物質粒
子BＡ0 に２５重量％の水酸化ナトリウム水溶液を含浸
させた後、各温度の加熱空気中で３時間熱処理し、アル
カリ熱処理済の被覆活物質粒子Ｈ-1、Ｈ-2、Ｈ-3、Ｈ-
4、Ｈ-5、Ｈ-6 を作製した。また、アルカリの種類と影
響を調べるため、上記水酸化ナトリウム水溶液の代わり
に２５重量％の水酸化カリウムム水溶液を用い、加熱温
度を８０℃とし、その他の条件を上記と同様にしてアル
カリ熱処理済被覆活物質粒子Ｈ-7を作製した。(Alkali heat treatment conditions) The coated active material particles BA 0 were impregnated with a 25% by weight aqueous solution of sodium hydroxide, and then heat-treated in heated air at each temperature for 3 hours to obtain alkali-heat-treated coated active material particles. H-1, H-2, H-3, H-
4, H-5 and H-6 were produced. Further, in order to investigate the type and effect of alkali, a 25 wt% potassium hydroxide aqueous solution was used in place of the sodium hydroxide aqueous solution, the heating temperature was set to 80 ° C., and the other conditions were the same as above, and the alkali heat treated coating was performed. Active material particles H-7 were prepared.
【００６５】次いで、上記各粒子を用い正極ＥBＡ0 の
場合と同様にして正極を作製するとともに、前記と同様
な方法で電気化学的特性を調べた。その結果を、アルカ
リ熱処理条件とともに表５に示す。Then, a positive electrode was prepared using the above particles in the same manner as the positive electrode EBA 0 , and the electrochemical characteristics were examined by the same method as described above. The results are shown in Table 5 together with the alkali heat treatment conditions.
【００６６】[0066]
【表５】 [Table 5]
【００６７】表５において、アルカリ熱処理を実施した
被覆活物質粒子Ｈ-2、Ｈ-3、Ｈ-4、Ｈ-5は、非アルカリ
熱処理の被覆活物質粒子BＡ0 （表２参照）に比較し、
単位活物質重量当たりの放電容量、過放電特性値の何れ
もが向上していた。しかし、Ｈ-1（熱処理温度３０℃）
は、BＡ0 と同様な特性値を示し、Ｈ-6（熱処理温度１
２０℃）では、単位活物質重量当たりの放電容量が低下
していた。このことから、アルカリ熱処理温度は４０℃
〜１００℃とするのが好ましく、被覆活物質粒子にこの
条件でアルカリ熱処理を行った場合、電気化学的特性が
顕著に高まる。In Table 5, the coated active material particles H-2, H-3, H-4, and H-5 subjected to the alkali heat treatment are compared with the non-alkali heat treated coated active material particles BA 0 (see Table 2). Then
Both the discharge capacity per unit weight of the active material and the overdischarge characteristic value were improved. However, H-1 (heat treatment temperature 30 ℃)
Shows the same characteristic values as BA 0, and H-6 (heat treatment temperature 1
At 20 ° C.), the discharge capacity per unit active material weight was reduced. From this, the alkali heat treatment temperature is 40 ° C.
The temperature is preferably -100 ° C, and when the coated active material particles are subjected to the alkali heat treatment under these conditions, the electrochemical characteristics are remarkably improved.
【００６８】他方、水酸化カリウム水溶液を用いてアル
カリ熱処理を行ったＨ-7は、Ｈ-2〜Ｈ-5よりも更に優れ
た電気化学的特性を示した。このことから、アルカリ熱
処理におけるアルカリ金属としては、好ましくは水酸化
カリウムを使用するのがよい。On the other hand, H-7 which had been subjected to alkali heat treatment using an aqueous solution of potassium hydroxide showed more excellent electrochemical characteristics than H-2 to H-5. From this, potassium hydroxide is preferably used as the alkali metal in the alkali heat treatment.
【００６９】なお、アルカリ熱処理によって電気化学的
特性が向上するのは、被覆層のコバルト化合物が導電性
に優れる２価以上の高次コバルト化合物に変化し、また
被覆層が電解液と馴染み易い性状に変化するためと考え
れる。The electrochemical characteristics are improved by the alkali heat treatment because the cobalt compound in the coating layer is changed to a divalent or higher-order cobalt compound having excellent conductivity, and the coating layer is easily compatible with the electrolytic solution. It is thought to be due to the change to.
【発明の効果】以上に説明したように、本発明にかかる
固溶体活物質粒子では、コバルト化合物が濃度勾配をも
って活物質粒子中に分布し、かつ粒子表層に高濃度に存
在するように構成されている。したがって、コバルト化
合物が粒子全体に均一に分散した従来の固溶体活物質粒
子に比べ、少ない量のコバルト化合物の配合でもって効
率良く粒子導電性を向上させることができ、しかも粒子
表層とその内側直近さらにその内側直近（以下同様）と
のコバルト濃度差が少ないので、粒子表面のコバルト化
合物が充放電に伴って粒子内部に拡散しにくい。As described above, the solid solution active material particles according to the present invention are configured such that the cobalt compound is distributed in the active material particles with a concentration gradient and is present in a high concentration on the surface layer of the particles. There is. Therefore, as compared with the conventional solid solution active material particles in which the cobalt compound is uniformly dispersed throughout the particle, it is possible to efficiently improve the particle conductivity by blending a small amount of the cobalt compound, and moreover, the particle surface layer and the inner immediate vicinity thereof. Since the difference in cobalt concentration with the immediate vicinity of the inside (the same applies below) is small, the cobalt compound on the surface of the particle is less likely to diffuse inside the particle as it is charged and discharged.
【００７０】更に、この固溶体活物質粒子には、亜鉛化
合物、カドミウム化合物、マグネシウム化合物、マンガ
ン化合物からなる群より選択される１種以上の化合物
（第三の成分）が配合してあるので、この化合物がコバ
ルト化合物の拡散を抑制するように作用して上記Ｃｏ濃
度勾配の効果を増強する。Further, since the solid solution active material particles are blended with at least one compound (third component) selected from the group consisting of a zinc compound, a cadmium compound, a magnesium compound and a manganese compound. The compound acts to suppress the diffusion of the cobalt compound and enhances the effect of the Co concentration gradient.
【００７１】更にまた、このような特性を有する固溶体
活物質粒子を主成分とし、これに別途水酸化コバルト粉
末を配合してなる本発明正極活物質では、上記の説明と
同様理由から、粉末添加のコバルト化合物が充放電にと
もなって活物質粒子内部に拡散して減少することがな
い。したがって、粒子表面近傍に常に高濃度に存在する
水酸化コバルトが、粒子相互間の導電性を好適に維持す
る。Further, in the positive electrode active material of the present invention, which comprises the solid solution active material particles having such characteristics as the main component, and the cobalt hydroxide powder is separately added thereto, the powder addition is performed for the same reason as described above. The cobalt compound is not diffused and reduced inside the active material particles during charge and discharge. Therefore, the cobalt hydroxide, which is always present in a high concentration in the vicinity of the surface of the particles, preferably maintains the conductivity between the particles.
【００７２】一方、本発明にかかる被覆活物質粒子で
は、水酸化コバルトを粉末で添加することに代え、水酸
化コバルトを粒子表面に被覆してある。このような被覆
活物質粒子では、水酸化コバルトが常に粒子表面に密着
した状態で存在しているので、水酸化コバルトを粉末で
添加する場合に比べ、水酸化コバルトの導電性向上効果
が有利に発揮される。On the other hand, in the coated active material particles according to the present invention, the surface of the particles is coated with cobalt hydroxide instead of adding cobalt hydroxide as powder. In such coated active material particles, since cobalt hydroxide is always present in a state of being in close contact with the particle surface, the effect of improving the conductivity of cobalt hydroxide is advantageous as compared with the case where cobalt hydroxide is added as a powder. To be demonstrated.
【００７３】更に、本発明では、このような被覆活物質
粒子をアルカリ熱処理して、被覆層を好適な性状に改質
し、一層の電気化学的特性の向上を図ってある。即ち、
被覆活物質粒子に対しアルカリ熱処理を施した場合、被
覆層を構成するコバルト化合物がより導電性に優れた２
価以上のコバルト化合物に変化するとともに、被覆層が
ポーラスなものとなり電解液との接触性が良くなる。し
たがって、このような被覆活物質粒子で正極を構成した
場合、正極内に好適な導電ネットワークが形成され、か
つ電解液との接触性もよいので、上記Ｃｏ濃度勾配の効
果や第三の成分の効果も加わって、いわゆるペースト式
における欠点である集電効率が改善され、電極活物質の
利用率が大幅に向上すると共に、単位活物質重量当たり
の電気容量（エネルギー密度）が高まる。そしてこの効
果は、特に過放電時において顕著に発揮される。Further, in the present invention, such coated active material particles are subjected to an alkali heat treatment to modify the coating layer to have a suitable property, thereby further improving the electrochemical characteristics. That is,
When the coated active material particles were subjected to an alkali heat treatment, the cobalt compound forming the coating layer was more excellent in conductivity.
At the same time as changing to a cobalt compound having a valency or more, the coating layer becomes porous and the contact with the electrolytic solution is improved. Therefore, when a positive electrode is formed of such coated active material particles, since a suitable conductive network is formed in the positive electrode and the contact with the electrolytic solution is good, the effect of the Co concentration gradient and the third component In addition to the effect, the current collection efficiency, which is a drawback of the so-called paste method, is improved, the utilization rate of the electrode active material is significantly improved, and the electric capacity (energy density) per unit active material weight is increased. And this effect is remarkably exhibited especially at the time of over-discharge.
【００７４】また、本発明製造方法によれば、比較的簡
易な方法で確実かつ安定して上記のような優れた固溶体
活物質粒子および被覆活物質粒子を製造できる。よっ
て、単位活物質重量当たりの電気容量が高く、かつ過放
電特性に優れたアルカリ蓄電池用正極活物質を安価に供
給できるという効果が得られる。According to the production method of the present invention, the excellent solid solution active material particles and coated active material particles as described above can be produced reliably and stably by a relatively simple method. Therefore, it is possible to obtain the effect that the positive electrode active material for an alkaline storage battery, which has a high electric capacity per unit active material weight and is excellent in overdischarge characteristics, can be supplied at a low cost.
Claims (11)
化合物とを含有する固溶体粒子を必須構成要素とするア
ルカリ蓄電池用正極活物質であって、 前記固溶体粒子は、粒子表層に高く粒子中心部に向かっ
て減少するコバルト濃度勾配を有することを特徴とする
アルカリ蓄電池用正極活物質。1. A positive electrode active material for an alkaline storage battery, which comprises, as an essential component, solid solution particles containing at least nickel hydroxide and a cobalt compound, wherein the solid solution particles are high on the surface layer of the particles and are directed toward the center part of the particles. A positive electrode active material for an alkaline storage battery, which has a decreasing cobalt concentration gradient.
バルト濃度と同等以上のコバルト濃度を有する水酸化コ
バルト被覆層が粒子表面に形成されたものである、こと
を特徴とする請求項１記載のアルカリ蓄電池用正極活物
質。2. The solid solution particles are characterized in that a cobalt hydroxide coating layer having a cobalt concentration equal to or higher than the cobalt concentration of the particle surface layer is further formed on the particle surface. Positive electrode active material for alkaline storage batteries.
バルトは、被覆層の形成された固溶体粒子をアルカリと
酸素の共存下で加熱処理することによって、２価を超え
るコバルト化合物とされていることを特徴とする請求項
２記載のアルカリ蓄電池用正極活物質。3. The cobalt hydroxide in the cobalt hydroxide coating layer is made into a cobalt compound having a valence of more than two by subjecting the solid solution particles having the coating layer formed thereon to heat treatment in the presence of alkali and oxygen. The positive electrode active material for an alkaline storage battery according to claim 2, wherein
記固溶体粒子と、前記固溶体粒子表層のコバルト濃度と
同等以上のコバルト濃度を有する水酸化コバルト含有粉
末とを含むことを特徴とする請求項１記載のアルカリ蓄
電池用正極活物質。4. The positive electrode active material for an alkaline storage battery contains the solid solution particles and a cobalt hydroxide-containing powder having a cobalt concentration equal to or higher than the cobalt concentration of the surface layer of the solid solution particles. A positive electrode active material for an alkaline storage battery as described above.
カドミウム化合物、マグネシウム化合物、マンガン化合
物からなる群より選択される１種以上の化合物を含有す
る、ことを特徴とする請求項１ないし請求項４記載のア
ルカリ蓄電池用正極活物質。5. The solid solution particles further include a zinc compound,
The positive electrode active material for an alkaline storage battery according to claim 1, further comprising at least one compound selected from the group consisting of a cadmium compound, a magnesium compound and a manganese compound.
合物を含有してなるアルカリ蓄電池用固溶体活物質粒子
の製造方法において、 前記アルカリ蓄電池用固溶体活物質粒子の製造方法は、
攪拌下ニッケル塩溶液に対し、コバルト塩添加量が連続
的または段階的に増加するようにコバルト塩溶液を注加
し、これと同時並行的にアルカリ溶液を注加して反応溶
液ｐＨを所定値に維持することにより、粒子中心部で低
く粒子表層に高いコバルト濃度勾配を有するニッケル・
コバルト固溶体粒子を作製する固溶体粒子作製工程を備
えることを特徴とするアルカリ蓄電池用固溶体活物質粒
子の製造方法。6. A method for producing solid solution active material particles for an alkaline storage battery, which comprises at least nickel hydroxide and a cobalt compound, wherein the method for producing solid solution active material particles for an alkaline storage battery comprises:
The cobalt salt solution is added to the nickel salt solution under stirring so that the amount of cobalt salt added increases continuously or stepwise, and at the same time, the alkaline solution is added to bring the reaction solution pH to a predetermined value. By maintaining the above, nickel having a high cobalt concentration gradient on the surface of the particle
A method for producing solid solution active material particles for an alkaline storage battery, comprising a solid solution particle producing step of producing cobalt solid solution particles.
溶液中にアンモニアを存在させることを特徴とする請求
項６記載のアルカリ蓄電池用固溶体活物質粒子の製造方
法。7. The method for producing solid solution active material particles for an alkaline storage battery according to claim 6, wherein ammonia is present in the reaction solution in the solid solution particle producing step.
少なくともコバルト塩を溶解したコバルト塩溶液に攪拌
分散し、この攪拌分散液にアルカリ溶液を注加し分散液
ｐＨを所定値に調整することによりコバルト化合物を析
出させ、前記ニッケル・コバルト固溶体粒子の表面に水
酸化コバルト被覆層を形成する被覆層形成工程を更に備
える、ことを特徴とする請求項６ないし請求項７記載の
アルカリ蓄電池用固溶体活物質粒子の製造方法。8. The nickel-cobalt solid solution particles,
At least a cobalt salt solution is stirred and dispersed in a cobalt salt solution, and an alkaline solution is added to this stirred dispersion liquid to adjust the pH of the dispersion liquid to a predetermined value to precipitate a cobalt compound, and the surface of the nickel-cobalt solid solution particles The method for producing solid solution active material particles for an alkaline storage battery according to claim 6, further comprising: a coating layer forming step of forming a cobalt hydroxide coating layer.
覆固溶体粒子にアルカリ金属溶液を含浸させた後、酸素
存在下で熱処理するアルカリ熱処理工程を備える、こと
を特徴とする請求項８記載のアルカリ蓄電池用固溶体活
物質粒子の製造方法。9. The method according to claim 8, further comprising an alkali heat treatment step of heat-treating in the presence of oxygen after impregnating the coated solid solution particles produced in the coating layer forming step with an alkali metal solution. A method for producing solid solution active material particles for an alkaline storage battery.
ウム溶液であることを特徴とする請求項９記載のアルカ
リ蓄電池用固溶体活物質粒子の製造方法。10. The method for producing solid solution active material particles for an alkaline storage battery according to claim 9, wherein the alkali metal solution is a potassium hydroxide solution.
であることを特徴とする請求項９ないし請求項１０記載
のアルカリ蓄電池用固溶体活物質粒子の製造方法。11. The temperature of the heat treatment is 40 to 100 ° C.
11. The method for producing solid solution active material particles for an alkaline storage battery according to claim 9, wherein
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23095195A JP3541090B2 (en) | 1995-09-08 | 1995-09-08 | Positive active material for alkaline storage battery and method for producing the same |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23095195A JP3541090B2 (en) | 1995-09-08 | 1995-09-08 | Positive active material for alkaline storage battery and method for producing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0982319A true JPH0982319A (en) | 1997-03-28 |
| JP3541090B2 JP3541090B2 (en) | 2004-07-07 |
Family
ID=16915881
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23095195A Expired - Lifetime JP3541090B2 (en) | 1995-09-08 | 1995-09-08 | Positive active material for alkaline storage battery and method for producing the same |
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| Country | Link |
|---|---|
| JP (1) | JP3541090B2 (en) |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0833397A1 (en) * | 1996-09-20 | 1998-04-01 | Matsushita Electric Industrial Co., Ltd. | Positive electrode active material for alkaline storage batteries |
| EP0881698A1 (en) | 1997-05-30 | 1998-12-02 | Matsushita Electric Industrial Co., Ltd. | Alkaline storage battery |
| US6013390A (en) * | 1997-04-01 | 2000-01-11 | Matsushita Electric Industrial Co., Ltd. | Alkaline storage battery |
| US6066416A (en) * | 1995-11-22 | 2000-05-23 | Matsushita Electric Industrial Co., Ltd. | Nickel hydroxide positive electrode active material having a surface layer containing a solid solution nickel hydroxide with manganese incorporated therein |
| GB2380147A (en) * | 2000-11-09 | 2003-04-02 | Bradford Particle Design Ltd | Particulate products |
| US9700529B2 (en) | 2002-05-03 | 2017-07-11 | Nektar Therapeutics | Particulate materials |
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| CN108475780A (en) * | 2016-01-05 | 2018-08-31 | 巴斯夫公司 | nickel hydroxide composite material for alkaline rechargeable battery |
| CN113772749A (en) * | 2021-11-15 | 2021-12-10 | 中南大学 | Double-gradient-structure nickel-cobalt-manganese ternary positive electrode material precursor, preparation method thereof and ternary positive electrode material |
| CN117525386A (en) * | 2024-01-08 | 2024-02-06 | 宁波容百新能源科技股份有限公司 | High-nickel positive electrode material, and preparation method and application thereof |
| CN117525386B (en) * | 2024-01-08 | 2024-05-14 | 宁波容百新能源科技股份有限公司 | High-nickel positive electrode material, and preparation method and application thereof |
-
1995
- 1995-09-08 JP JP23095195A patent/JP3541090B2/en not_active Expired - Lifetime
Cited By (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6066416A (en) * | 1995-11-22 | 2000-05-23 | Matsushita Electric Industrial Co., Ltd. | Nickel hydroxide positive electrode active material having a surface layer containing a solid solution nickel hydroxide with manganese incorporated therein |
| EP0833397A1 (en) * | 1996-09-20 | 1998-04-01 | Matsushita Electric Industrial Co., Ltd. | Positive electrode active material for alkaline storage batteries |
| US6261720B1 (en) | 1996-09-20 | 2001-07-17 | Matsushita Electric Industrial Co., Ltd. | Positive electrode active material for alkaline storage batteries |
| EP1195824A2 (en) * | 1996-09-20 | 2002-04-10 | Matsushita Electric Industrial Co., Ltd. | Positive electrode active material for alkaline storage batteries |
| EP1195824A3 (en) * | 1996-09-20 | 2002-04-24 | Matsushita Electric Industrial Co., Ltd. | Positive electrode active material for alkaline storage batteries |
| US6013390A (en) * | 1997-04-01 | 2000-01-11 | Matsushita Electric Industrial Co., Ltd. | Alkaline storage battery |
| EP0881698A1 (en) | 1997-05-30 | 1998-12-02 | Matsushita Electric Industrial Co., Ltd. | Alkaline storage battery |
| US7115280B2 (en) | 2000-11-09 | 2006-10-03 | Nektar Therapeutics Uk, Ltd. | Particle formation methods and their products |
| GB2380147A (en) * | 2000-11-09 | 2003-04-02 | Bradford Particle Design Ltd | Particulate products |
| US9700529B2 (en) | 2002-05-03 | 2017-07-11 | Nektar Therapeutics | Particulate materials |
| US10188614B2 (en) | 2002-05-03 | 2019-01-29 | Nektar Therapeutics | Particulate materials |
| US10945972B2 (en) | 2002-05-03 | 2021-03-16 | Nektar Therapeutics | Particulate materials |
| US9808030B2 (en) | 2011-02-11 | 2017-11-07 | Grain Processing Corporation | Salt composition |
| CN108475780A (en) * | 2016-01-05 | 2018-08-31 | 巴斯夫公司 | nickel hydroxide composite material for alkaline rechargeable battery |
| US10651459B2 (en) * | 2016-01-05 | 2020-05-12 | Basf Corporation | Nickel hydroxide composite material for alkaline rechargeable battery |
| CN113772749A (en) * | 2021-11-15 | 2021-12-10 | 中南大学 | Double-gradient-structure nickel-cobalt-manganese ternary positive electrode material precursor, preparation method thereof and ternary positive electrode material |
| CN117525386A (en) * | 2024-01-08 | 2024-02-06 | 宁波容百新能源科技股份有限公司 | High-nickel positive electrode material, and preparation method and application thereof |
| CN117525386B (en) * | 2024-01-08 | 2024-05-14 | 宁波容百新能源科技股份有限公司 | High-nickel positive electrode material, and preparation method and application thereof |
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