JP7290625B2 - Positive electrode compound and method for producing positive electrode active material - Google Patents

Positive electrode compound and method for producing positive electrode active material Download PDF

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JP7290625B2
JP7290625B2 JP2020507754A JP2020507754A JP7290625B2 JP 7290625 B2 JP7290625 B2 JP 7290625B2 JP 2020507754 A JP2020507754 A JP 2020507754A JP 2020507754 A JP2020507754 A JP 2020507754A JP 7290625 B2 JP7290625 B2 JP 7290625B2
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positive electrode
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coating layer
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JPWO2019181787A1 (en
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聡 田中
直也 花村
未来夫 畑
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
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    • C01G53/00—Compounds of nickel
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/006—Compounds containing, besides nickel, two or more other elements, with the exception of oxygen or hydrogen
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/40—Nickelates
    • C01G53/42—Nickelates containing alkali metals, e.g. LiNiO2
    • H—ELECTRICITY
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0002—Aqueous electrolytes
    • H01M2300/0014—Alkaline electrolytes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • 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
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    • 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

Description

本発明は、蓄電池の正極用化合物に関し、特に、高導電性を有し、すなわち、体積抵抗率が低く、高温放置後及び初期特性において優れた利用率を有する正極用化合物に関するものである。 TECHNICAL FIELD The present invention relates to a positive electrode compound for a storage battery, and more particularly to a positive electrode compound having high electrical conductivity, that is, having a low volume resistivity and excellent utilization after high temperature storage and initial characteristics.

蓄電池の正極用化合物の高性能化のために、核である金属水酸化物の表面に金属元素を有する被覆層を形成することがある。例えば、高い正極利用率と、サイクル特性を向上させたアルカリ蓄電池用正極活物質として、核である水酸化ニッケルの表面をコバルト酸化物で被覆した表面修飾水酸化ニッケルが提案されている（特許文献１）。 In order to improve the performance of a positive electrode compound for a storage battery, a coating layer containing a metal element may be formed on the surface of the metal hydroxide, which is the core. For example, as a positive electrode active material for alkaline storage batteries with a high positive electrode utilization rate and improved cycle characteristics, surface-modified nickel hydroxide in which the surface of the core nickel hydroxide is coated with cobalt oxide has been proposed (Patent Document 1).

しかし、特許文献１の水酸化ニッケルの表面をコバルト酸化物で被覆した正極活物質では、２５℃ではまずまずの利用率とサイクル特性が得られるものの、高温放置後における利用率と導電性に改善の余地があった。また、初期特性における利用率にも改善の余地があった。そこで、特許文献１では、正極板を作製する際に、導電助剤を添加して導電性を向上させることで利用率の向上を図ることが行われていた。 However, in the positive electrode active material of Patent Document 1, in which the surface of nickel hydroxide is coated with cobalt oxide, reasonable utilization and cycle characteristics can be obtained at 25° C., but there is no improvement in utilization and conductivity after being left at high temperature. There was room. In addition, there is room for improvement in the utilization rate of the initial characteristics. Therefore, in Patent Literature 1, when a positive electrode plate is produced, a conductive additive is added to improve the conductivity, thereby improving the utilization rate.

また、水酸化ニッケル表面に金属被覆層を形成する方法として、水酸化ニッケル微粒子を無電解めっき浴中で撹拌しながら、塩化パラジウム及び塩酸を主成分とする溶液を投入することにより、水酸化ニッケル微粒子の表面にパラジウム触媒を担持させると同時に無電解めっきを行うことで、無電解めっきの被覆層を形成することが提案されている（特許文献２）。特許文献２では、無電解めっきの被覆層は、ニッケル－リンの複合被膜からなるものである。 In addition, as a method for forming a metal coating layer on the surface of nickel hydroxide, while stirring nickel hydroxide fine particles in an electroless plating bath, a solution containing palladium chloride and hydrochloric acid as main components is added to nickel hydroxide. It has been proposed to form an electroless plating coating layer by carrying a palladium catalyst on the surface of fine particles and performing electroless plating at the same time (Patent Document 2). In Patent Document 2, the coating layer for electroless plating is composed of a nickel-phosphorus composite coating.

このように、特許文献２では、無電解めっきの被覆層にはリン元素が多く含有されている。しかし、リン元素は蓄電池の性能向上、特に、高温放置後及び初期特性における利用率と導電性に改善の余地があった。 Thus, in Patent Document 2, the electroless plating coating layer contains a large amount of elemental phosphorus. However, the phosphorus element leaves room for improvement in the performance of storage batteries, particularly in the utilization rate and electrical conductivity after being left at high temperature and in the initial characteristics.

従って、特許文献２でも、正極板を作製する際に、導電助剤を添加して導電性を向上させることで利用率の向上を図ることが行われていた。 Therefore, in Patent Document 2 as well, when manufacturing a positive electrode plate, a conductive additive is added to improve the conductivity, thereby improving the utilization rate.

特開２００１－５２６９５号公報JP-A-2001-52695 特開２００４－３１５９４６号公報Japanese Patent Application Laid-Open No. 2004-315946

上記事情に鑑み、本発明の目的は、高温放置後及び初期特性における利用率に優れ、高導電性を有する正極用化合物を提供することにある。 SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a positive electrode compound which is excellent in utilization rate after being left at a high temperature and in initial characteristics, and which has high conductivity.

本発明の態様は、一次粒子が凝集した二次粒子であり、ニッケル複合水酸化物を含む核と、前記核の表面にコバルト元素が５００ｐｐｍ以下及びリン元素が１０ｐｐｍ以下であるニッケル元素を含む被覆層と、を有する正極用化合物であり、前記被覆層のニッケル元素の含有量が、前記核１００質量部に対して６質量部以上２０質量部以下、体積抵抗率が１．５×１０Ω・ｃｍ以下であり、アルカリ蓄電池の正極活物質用である正極用化合物である。 An aspect of the present invention is a secondary particle in which primary particles are aggregated, a core containing a nickel composite hydroxide, and a coating containing a nickel element having a cobalt element of 500 ppm or less and a phosphorus element of 10 ppm or less on the surface of the core. A positive electrode compound having a layer, wherein the nickel element content of the coating layer is 6 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the core, and the volume resistivity is 1.5 × 10 Ω cm It is the following and is a compound for positive electrodes which is for positive electrode active materials of alkaline storage batteries.

本発明の態様は、一次粒子が凝集した二次粒子であり、ニッケル複合水酸化物を含む核と、前記核の表面にコバルト元素が５００ｐｐｍ以下及びリン元素が１０ｐｐｍ以下であるニッケル元素を含む被覆層と、を有する正極用化合物であり、前記被覆層のニッケル元素の含有量が、前記核１００質量部に対して６質量部以上２０質量部以下、体積抵抗率が５．０×１０2Ω・ｃｍ以下であり、非水系電解質二次電池の正極活物質用である正極用化合物である。 An aspect of the present invention is a secondary particle in which primary particles are aggregated, a core containing a nickel composite hydroxide, and a coating containing a nickel element having a cobalt element of 500 ppm or less and a phosphorus element of 10 ppm or less on the surface of the core. a layer, wherein the content of nickel element in the coating layer is 6 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the core, and the volume resistivity is 5.0 × 10 2 Ω cm or less, and is a positive electrode compound for a positive electrode active material of a non-aqueous electrolyte secondary battery.

本発明の態様は、一次粒子が凝集した二次粒子であり、ニッケル複合水酸化物を含む核と、前記核の表面にコバルト元素が５００ｐｐｍ以下及びリン元素が１０ｐｐｍ以下であるニッケル元素を含む被覆層と、を有する正極用化合物であり、前記被覆層のニッケル元素の含有量が、前記核１００質量部に対して６質量部以上２０質量部以下、体積抵抗率が１．５×１０８Ω・ｃｍ以下であり、非水系電解質二次電池の正極活物質の前駆体用である正極用化合物である。 An aspect of the present invention is a secondary particle in which primary particles are aggregated, a core containing a nickel composite hydroxide, and a coating containing a nickel element having a cobalt element of 500 ppm or less and a phosphorus element of 10 ppm or less on the surface of the core. and a nickel element content of the coating layer is 6 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the core, and the volume resistivity is 1.5 × 10 8 Ω. cm or less, and is a positive electrode compound for a precursor of a positive electrode active material of a non-aqueous electrolyte secondary battery.

本発明の態様は、前記核が、コバルト、亜鉛、マンガン、リチウム、マグネシウム、アルミニウム、ジルコニウム、イットリウム、イッテルビウム及びタングステンからなる群から選択された金属元素を少なくとも１種含む正極用化合物である。 An aspect of the present invention is a positive electrode compound in which the nucleus contains at least one metal element selected from the group consisting of cobalt, zinc, manganese, lithium, magnesium, aluminum, zirconium, yttrium, ytterbium and tungsten.

本発明の態様は、前記ニッケル元素を含む被覆層の平均一次粒子径が、１０ｎｍ以上１００ｎｍ以下である正極用化合物である。本明細書では、被覆層のニッケル元素の平均一次粒子径は、電界放出形走査電子顕微鏡（ＦＥ－ＳＥＭ）にて被覆層を観察した画像から一次粒子を１０個選択し、選択した上記一次粒子の最長直径の部位を、それぞれ測定した値の平均値を意味する。 An aspect of the present invention is the compound for positive electrode, wherein the coating layer containing the nickel element has an average primary particle size of 10 nm or more and 100 nm or less. In this specification, the average primary particle size of the nickel element in the coating layer is obtained by selecting 10 primary particles from an image of the coating layer observed with a field emission scanning electron microscope (FE-SEM), and selecting the primary particles. Means the average value of the values measured for the longest diameter part of the .

本発明の態様は、さらに、パラジウム化合物を含む正極用化合物である。 An aspect of the invention is further a positive electrode compound comprising a palladium compound.

本発明の態様は、前記核が、一般式（１）
Ｎｉ（１－ｘ）Ｍｘ（ＯＨ）２＋ａ （１）
（式中：０＜ｘ≦０．２、０≦ａ≦０．２、Ｍは、コバルト、亜鉛、マンガン、マグネシウム、アルミニウム、イットリウム及びイッテルビウムからなる群から選択された少なくとも１種の金属元素を示す。）で表される正極用化合物である。In an embodiment of the present invention, the core is represented by general formula (1)
Ni (1−x) M x (OH) 2+a (1)
(In the formula: 0 < x ≤ 0.2, 0 ≤ a ≤ 0.2, M is at least one metal element selected from the group consisting of cobalt, zinc, manganese, magnesium, aluminum, yttrium and ytterbium ) is a positive electrode compound represented by

本発明の態様は、前記核が、一般式（３）
Ｎｉ（１－ｚ）Ｐｚ（ＯＨ）２＋ｃ （３）
（式中：０＜ｚ≦０．７、０≦ｃ≦０．２８、Ｐは、コバルト、亜鉛、マンガン、マグネシウム、アルミニウム、ジルコニウム、イットリウム、イッテルビウム及びタングステンからなる群から選択された少なくとも１種の金属元素を示す。）で表される正極用化合物である。In an embodiment of the present invention, the core is represented by general formula (3)
Ni (1−z) P z (OH) 2+c (3)
(In the formula: 0 < z ≤ 0.7, 0 ≤ c ≤ 0.28, P is at least one selected from the group consisting of cobalt, zinc, manganese, magnesium, aluminum, zirconium, yttrium, ytterbium and tungsten shows the metal element of.) is a positive electrode compound represented by.

本発明の態様は、上記正極用化合物を前駆体として用いた、非水系電解質二次電池用正極活物質である。 An aspect of the present invention is a positive electrode active material for a non-aqueous electrolyte secondary battery using the positive electrode compound as a precursor.

本発明の態様は、前記核が、一般式（２）
Ｌｉ［Ｌｉｙ（Ｎｉ（１－ｂ）Ｎｂ）１－ｙ］Ｏ２ （２）
（式中：０＜ｂ≦０．７、０≦ｙ≦０．５０、Ｎは、コバルト、マンガン、マグネシウム、アルミニウム、ジルコニウム、イットリウム、イッテルビウム及びタングステンからなる群から選択された少なくとも１種の金属元素を示す。）で表される正極用化合物である。In an embodiment of the present invention, the core is represented by general formula (2)
Li[Li y (Ni (1-b) N b ) 1-y ]O 2 (2)
(In the formula: 0 < b ≤ 0.7, 0 ≤ y ≤ 0.50, N is at least one metal selected from the group consisting of cobalt, manganese, magnesium, aluminum, zirconium, yttrium, ytterbium and tungsten represents an element.) is a positive electrode compound represented by

本発明の態様によれば、ニッケル複合水酸化物を含む核と、核の表面にコバルト元素が５００ｐｐｍ以下及びリン元素が１０ｐｐｍ以下であるニッケル元素を含む被覆層と、を有し、被覆層のニッケル元素の含有量が、核１００質量部に対して６質量部以上２０質量部以下であることにより、高温放置後及び初期特性における利用率に優れた正極用化合物を得ることができる。また、体積抵抗率が１．５×１０Ω・ｃｍ以下なので、高導電性を有する正極用化合物を得ることができる。従って、正極用化合物を用いて正極板を作製する際に、導電助剤の添加量を低減、または導電助剤を添加しなくても、正極板は優れた導電性を得ることができる。 According to an aspect of the present invention, a core containing a nickel composite hydroxide and a coating layer containing a nickel element containing 500 ppm or less of cobalt and 10 ppm or less of phosphorus on the surface of the core, When the content of the nickel element is 6 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the core, it is possible to obtain a positive electrode compound having an excellent utilization rate after being left at a high temperature and in the initial characteristics. Moreover, since the volume resistivity is 1.5×10 Ω·cm or less, a positive electrode compound having high conductivity can be obtained. Therefore, when the positive electrode plate is produced using the positive electrode compound, the positive electrode plate can have excellent conductivity even if the amount of the conductive additive is reduced or no conductive additive is added.

本発明の態様によれば、被覆層のニッケル元素の平均一次粒子径が、１０ｎｍ以上１００ｎｍ以下であることにより、被覆層のニッケル元素粒子が微細化されて、正極用化合物の導電性をさらに向上させることができる。 According to the aspect of the present invention, since the average primary particle size of the nickel element in the coating layer is 10 nm or more and 100 nm or less, the nickel element particles in the coating layer are made finer, and the conductivity of the positive electrode compound is further improved. can be made

以下に、本発明の正極用化合物について、詳細を説明する。本発明の正極用化合物は、一次粒子が凝集した二次粒子であり、ニッケル複合水酸化物を含む核と、前記核の表面にコバルト元素が５００ｐｐｍ以下及びリン元素が１０ｐｐｍ以下であるニッケル元素を含む被覆層と、を有する正極用化合物であり、前記被覆層のニッケル元素の含有量が、前記核１００質量部に対して６質量部以上２０質量部以下、体積抵抗率が１．５×１０Ω・ｃｍ以下である正極用化合物である。従って、本発明の正極用化合物は、コア・シェル構造を有した粒子であり、ニッケルを含む複合水酸化物粒子の核とニッケルを含む被覆層を有する、ニッケル含有被覆ニッケル複合水酸化物となっている。 Below, the compound for positive electrodes of this invention is demonstrated in detail. The positive electrode compound of the present invention is secondary particles in which primary particles are agglomerated, and includes a nucleus containing a nickel composite hydroxide and a nickel element having a cobalt element content of 500 ppm or less and a phosphorus element content of 10 ppm or less on the surface of the nucleus. A positive electrode compound having a coating layer containing a nickel element content of 6 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the nuclei, and a volume resistivity of 1.5 × 10 Ω · It is a compound for a positive electrode which is cm or less. Therefore, the positive electrode compound of the present invention is a particle having a core-shell structure, and is a nickel-containing coated nickel composite hydroxide having a nucleus of nickel-containing composite hydroxide particles and a nickel-containing coating layer. ing.

粒子状である本発明の正極用化合物の形状は、特に限定されず、例えば、略球形を挙げることができる。 The shape of the particulate positive electrode compound of the present invention is not particularly limited, and for example, it may be substantially spherical.

本発明の正極用化合物は、複数の一次粒子が凝集して形成された二次粒子である。本発明の正極用化合物の体積抵抗率は、１．５×１０Ω・ｃｍ以下である。被覆層のニッケル元素が微細化されていることが、導電性の向上に寄与していると考えられる。正極用化合物の体積抵抗率は、１．５×１０Ω・ｃｍ以下であれば、特に限定されず、低い体積抵抗率ほど好ましいが、例えば、１．５Ω・ｃｍ以下がより好ましく、１．０×１０－１Ω・ｃｍ以下がさらに好ましく、２．０×１０－２Ω・ｃｍ以下が特に好ましい。正極用化合物の体積抵抗率の下限値は、特に限定されないが、例えば、効率的に製造可能である点で、１．０×１０－４Ω・ｃｍである。The positive electrode compound of the present invention is secondary particles formed by aggregation of a plurality of primary particles. The volume resistivity of the positive electrode compound of the present invention is 1.5×10 Ω·cm or less. It is considered that the refinement of the nickel element in the coating layer contributes to the improvement of conductivity. The volume resistivity of the positive electrode compound is not particularly limited as long as it is 1.5 × 10 Ω cm or less, and a lower volume resistivity is preferable. 10 −1 Ω·cm or less is more preferable, and 2.0×10 −2 Ω·cm or less is particularly preferable. Although the lower limit of the volume resistivity of the positive electrode compound is not particularly limited, it is, for example, 1.0×10 −4 Ω·cm in view of efficient production.

正極用化合物の粒度分布は、特に限定されないが、例えば、累積体積百分率が５０体積％の二次粒子径Ｄ５０（以下、単に「Ｄ５０」ということがある。）の下限値は、高温耐性を得る点から、２．０μｍが好ましく、２．５μｍがより好ましく、３．０μｍが特に好ましい。一方で、正極用化合物のＤ５０の上限値は、密度の向上と電解液との接触面を確保することのバランスの点から、３０．０μｍが好ましく、２５．０μｍが特に好ましい。なお、上記した下限値、上限値は、任意で組み合わせることができる。 The particle size distribution of the positive electrode compound is not particularly limited, but for example, the lower limit of the secondary particle diameter D50 (hereinafter sometimes simply referred to as "D50") at a cumulative volume percentage of 50% by volume provides high temperature resistance. From the point of view, 2.0 μm is preferable, 2.5 μm is more preferable, and 3.0 μm is particularly preferable. On the other hand, the upper limit of D50 of the positive electrode compound is preferably 30.0 μm, particularly preferably 25.0 μm, from the viewpoint of the balance between improving the density and securing the contact surface with the electrolytic solution. In addition, the above-described lower limit value and upper limit value can be combined arbitrarily.

正極用化合物の核の組成としては、ニッケル水酸化物を含む組成であれば、特に限定されないが、必要に応じて、ニッケルの他に、さらに、コバルト、亜鉛、マンガン、リチウム、マグネシウム、アルミニウム、ジルコニウム、イットリウム、イッテルビウム及びタングステンからなる群から選択された少なくとも１種の金属元素を含む水酸化物でもよい。 The composition of the nucleus of the positive electrode compound is not particularly limited as long as it contains nickel hydroxide, but if necessary, cobalt, zinc, manganese, lithium, magnesium, aluminum, A hydroxide containing at least one metal element selected from the group consisting of zirconium, yttrium, ytterbium and tungsten may also be used.

本発明の正極用化合物は、例えば、アルカリ蓄電池の正極活物質用、非水系電解質二次電池の正極活物質用、非水系電解質二次電池の正極活物質の前駆体用として用いることができる。 The positive electrode compound of the present invention can be used, for example, as a positive electrode active material for alkaline storage batteries, a positive electrode active material for non-aqueous electrolyte secondary batteries, and a precursor of a positive electrode active material for non-aqueous electrolyte secondary batteries.

本発明の正極用化合物が、アルカリ蓄電池の正極活物質用として適用される場合、核の組成として下記一般式（１）
Ｎｉ（１－ｘ）Ｍｘ（ＯＨ）２＋ａ （１）
（式中：０＜ｘ≦０．２、０≦ａ≦０．２、Ｍは、コバルト、亜鉛、マンガン、マグネシウム、アルミニウム、イットリウム及びイッテルビウムからなる群から選択された少なくとも１種の金属元素を示す。）で表される正極用化合物を挙げることができる。When the positive electrode compound of the present invention is applied as a positive electrode active material for an alkaline storage battery, the composition of the core is represented by the following general formula (1)
Ni (1−x) M x (OH) 2+a (1)
(In the formula: 0 < x ≤ 0.2, 0 ≤ a ≤ 0.2, M is at least one metal element selected from the group consisting of cobalt, zinc, manganese, magnesium, aluminum, yttrium and ytterbium ) can be mentioned.

本発明の正極用化合物が、非水系電解質二次電池の正極活物質用として適用される場合、核の組成として下記一般式（２）
Ｌｉ［Ｌｉｙ（Ｎｉ（１－ｂ）Ｎｂ）１－ｙ］Ｏ２ （２）
（式中：０＜ｂ≦０．７、０≦ｙ≦０．５０、Ｎは、コバルト、マンガン、マグネシウム、アルミニウム、ジルコニウム、イットリウム、イッテルビウム及びタングステンからなる群から選択された少なくとも１種の金属元素を示す。）で表される正極用化合物を挙げることができる。When the positive electrode compound of the present invention is applied as a positive electrode active material for a non-aqueous electrolyte secondary battery, the composition of the core is represented by the following general formula (2)
Li[Li y (Ni (1-b) N b ) 1-y ]O 2 (2)
(In the formula: 0 < b ≤ 0.7, 0 ≤ y ≤ 0.50, N is at least one metal selected from the group consisting of cobalt, manganese, magnesium, aluminum, zirconium, yttrium, ytterbium and tungsten element.) can be mentioned.

非水系電解質二次電池の正極活物質用の正極用化合物は、ニッケル複合水酸化物にリチウムイオンを添加して焼成することで核（例えば、一般式（２）で表される核）を調製し、得られた核に、コバルト元素が５００ｐｐｍ以下及びリン元素が１０ｐｐｍ以下であり且つニッケル元素の含有量が核１００質量部に対して６質量部以上２０質量部以下であるニッケル元素を含む被覆層を形成することで、得ることができる。 A positive electrode compound for a positive electrode active material of a non-aqueous electrolyte secondary battery is prepared by adding lithium ions to nickel composite hydroxide and firing to prepare a nucleus (for example, a nucleus represented by general formula (2)). Then, on the obtained nucleus, a coating containing nickel element having a cobalt element content of 500 ppm or less, a phosphorus element content of 10 ppm or less, and a nickel element content of 6 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the nucleus. It can be obtained by forming layers.

また、本発明の正極用化合物が、非水系電解質二次電池の正極活物質の前駆体用として適用される場合、核の組成として下記一般式（３）
Ｎｉ（１－ｚ）Ｐｚ（ＯＨ）２＋ｃ （３）
（式中：０＜ｚ≦０．７、０≦ｃ≦０．２８、Ｐは、コバルト、亜鉛、マンガン、マグネシウム、アルミニウム、ジルコニウム、イットリウム、イッテルビウム及びタングステンからなる群から選択された少なくとも１種の金属元素を示す。）で表される正極用化合物を挙げることができる。Further, when the positive electrode compound of the present invention is applied as a precursor of a positive electrode active material for a non-aqueous electrolyte secondary battery, the composition of the core is represented by the following general formula (3)
Ni (1−z) P z (OH) 2+c (3)
(In the formula: 0 < z ≤ 0.7, 0 ≤ c ≤ 0.28, P is at least one selected from the group consisting of cobalt, zinc, manganese, magnesium, aluminum, zirconium, yttrium, ytterbium and tungsten is a metal element of.) can be mentioned.

ニッケル含有被覆ニッケル複合水酸化物である本発明の正極用化合物（例えば、一般式（３）で表される核を有するニッケル含有被覆ニッケル複合水酸化物）に、さらにリチウムイオンを添加して、焼成することで、非水系電解質二次電池の正極活物質を得ることができる。上記から、非水系電解質二次電池としては、例えば、リチウムイオン二次電池を挙げることができる。 Lithium ions are further added to the positive electrode compound of the present invention, which is a nickel-containing coated nickel composite hydroxide (for example, a nickel-containing coated nickel composite hydroxide having a nucleus represented by general formula (3)), By firing, a positive electrode active material for a non-aqueous electrolyte secondary battery can be obtained. As described above, non-aqueous electrolyte secondary batteries include, for example, lithium ion secondary batteries.

本発明の正極用化合物では、上記した核の表面は、コバルト元素が５００ｐｐｍ以下及びリン元素が１０ｐｐｍ以下であるニッケル元素を含む被覆層で被覆されている。上記コバルト元素及びリン元素の含有量は、被覆層中における含有量である。本発明の正極用化合物では、上記被覆層で被覆されていることで、高温放置後（例えば、９０℃程度）及び初期特性における利用率が向上し、さらに体積抵抗率が低減する。コバルト元素の含有量は５００ｐｐｍ以下であれば、特に限定されないが、高温放置後及び初期特性における利用率をより確実に向上させつつ体積抵抗率をより確実に低減させる点から、２００ｐｐｍ以下が好ましく、１００ｐｐｍ以下がより好ましく、５０ｐｐｍ以下がさらに好ましく、１０ｐｐｍ以下が特に好ましい。リン元素の含有量は、１０ｐｐｍ以下であれば、特に限定されないが、高温放置後及び初期特性における利用率をより確実に向上させつつ体積抵抗率をより確実に低減させる点から、５ｐｐｍ以下がより好ましく、２ｐｐｍ以下が特に好ましい。上記から、ニッケル元素を含む被覆層の主成分は、ニッケル元素である。 In the positive electrode compound of the present invention, the surface of the core is coated with a coating layer containing nickel containing 500 ppm or less of cobalt and 10 ppm or less of phosphorus. The content of the cobalt element and the phosphorus element is the content in the coating layer. In the positive electrode compound of the present invention, since it is covered with the above coating layer, the utilization rate is improved after being left at a high temperature (for example, about 90° C.) and in the initial characteristics, and the volume resistivity is reduced. The content of the cobalt element is not particularly limited as long as it is 500 ppm or less, but it is preferably 200 ppm or less from the viewpoint of more reliably improving the utilization factor in the initial characteristics after being left at high temperature and more reliably reducing the volume resistivity. 100 ppm or less is more preferable, 50 ppm or less is still more preferable, and 10 ppm or less is particularly preferable. The content of the phosphorus element is not particularly limited as long as it is 10 ppm or less, but from the point of more reliably reducing the volume resistivity while more reliably improving the utilization factor in the initial characteristics after being left at a high temperature, 5 ppm or less is more. Preferably, 2 ppm or less is particularly preferable. From the above, the main component of the coating layer containing nickel element is nickel element.

上記の通り、ニッケル元素を含む被覆層の組成は、コバルト元素が５００ｐｐｍ以下及びリン元素が１０ｐｐｍ以下であり、主にニッケル元素からなる。被覆層中におけるニッケルの含有量は、例えば、高温放置後及び初期特性における利用率をより確実に向上させる点から、９９質量％以上が好ましく、９９．９質量％以上がより好ましく、１００質量％が特に好ましい。 As described above, the composition of the coating layer containing nickel element is 500 ppm or less of cobalt element and 10 ppm or less of phosphorus element, and is mainly composed of nickel element. The content of nickel in the coating layer is preferably 99% by mass or more, more preferably 99.9% by mass or more, more preferably 100% by mass, in order to more reliably improve the utilization rate in the initial characteristics after being left at a high temperature, for example. is particularly preferred.

また、被覆層のニッケル元素の含有量は、核１００質量部に対して６質量部以上２０質量部以下の範囲である。被覆層のニッケル元素の含有量が核１００質量部に対して６質量部以上２０質量部以下であることにより、初期特性だけではなく高温放置後においても優れた利用率を得つつ、体積抵抗率を低減することができる。被覆層のニッケル元素の含有量は、核１００質量部に対して６質量部以上２０質量部以下であれば、特に限定されないが、体積抵抗率をさらに低減させつつ高温放置後及び初期特性における利用率をさらに向上させる点から、核１００質量部に対して７質量部以上１５質量部以下が特に好ましい。 Moreover, the content of the nickel element in the coating layer is in the range of 6 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the core. Since the content of the nickel element in the coating layer is 6 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the core, excellent utilization is obtained not only in the initial characteristics but also after being left at a high temperature, and the volume resistivity can be reduced. The content of the nickel element in the coating layer is not particularly limited as long as it is 6 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the core. From the point of further improving the rate, it is particularly preferable to use 7 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the core.

被覆層のニッケル元素は、粒子状である。ニッケル粒子が重なり合った状態で、ニッケル複合水酸化物を含む核表面を被覆している。被覆層の各ニッケル元素の形状は、特に限定されず、例えば、略球形である。 The nickel element in the coating layer is particulate. The surface of the core containing the nickel composite hydroxide is coated with the nickel particles in an overlapping state. The shape of each nickel element in the coating layer is not particularly limited, and is, for example, substantially spherical.

被覆層のニッケル元素の平均一次粒子径は、特に限定されないが、１０ｎｍ以上１００ｎｍ以下の範囲であることが好ましい。被覆層のニッケル元素の平均一次粒子径が１０ｎｍ以上１００ｎｍ以下であることにより、ニッケル元素が微細化されているので、被覆層の表面が平滑化、緻密化されて、正極用化合物の導電性をさらに向上、すなわち、体積抵抗率をさらに低減させることができる。被覆層のニッケル元素の平均一次粒子径は、２０ｎｍ以上８０ｎｍ以下がより好ましく、３０ｎｍ以上７０ｎｍ以下が特に好ましい。なお、ニッケル元素を含む被覆層は、ニッケル複合水酸化物を含む核の表面全体を被覆してもよく、ニッケル複合水酸化物を含む核の表面の一部領域を被覆していてもよい。 Although the average primary particle size of the nickel element in the coating layer is not particularly limited, it is preferably in the range of 10 nm or more and 100 nm or less. Since the nickel element in the coating layer has an average primary particle diameter of 10 nm or more and 100 nm or less, the nickel element is made fine, so that the surface of the coating layer is smoothed and densified, and the conductivity of the positive electrode compound is improved. Further improvement, that is, volume resistivity can be further reduced. The average primary particle size of the nickel element in the coating layer is more preferably 20 nm or more and 80 nm or less, and particularly preferably 30 nm or more and 70 nm or less. The coating layer containing the nickel element may cover the entire surface of the nucleus containing the nickel composite hydroxide, or may cover a partial region of the surface of the nucleus containing the nickel composite hydroxide.

また、被覆層の平均厚さは、特に限定されず、例えば、その下限値は、体積抵抗率をより確実に低減させる点から２０ｎｍが好ましく、７０ｎｍが特に好ましい。一方で、その上限値は、主に核が正極用化合物の電池特性の発揮に寄与するところ、正極用化合物の優れた電池特性を確実に維持する点から２００ｎｍが好ましく、１００ｎｍが特に好ましい。 The average thickness of the coating layer is not particularly limited. For example, the lower limit thereof is preferably 20 nm, particularly preferably 70 nm, from the viewpoint of reducing the volume resistivity more reliably. On the other hand, the upper limit is preferably 200 nm, particularly preferably 100 nm, from the viewpoint of reliably maintaining the excellent battery characteristics of the positive electrode compound, since the nucleus mainly contributes to the exhibition of the battery characteristics of the positive electrode compound.

後述するように、本発明の正極用化合物では、その製造にあたり、パラジウム触媒を使用する。従って、本発明の正極用化合物では、微量のパラジウム化合物が含まれる。正極用化合物中におけるパラジウム元素の含有量は、例えば、１ｐｐｍ以上１００ｐｐｍ以下である。 As will be described later, the positive electrode compound of the present invention uses a palladium catalyst in its production. Therefore, the positive electrode compound of the present invention contains a very small amount of palladium compound. The content of the palladium element in the positive electrode compound is, for example, 1 ppm or more and 100 ppm or less.

本発明の正極用化合物のＢＥＴ比表面積は、特に限定されないが、例えば、密度の向上と電解液との接触面を確保することのバランスの点から、下限値は０．１ｍ２／ｇが好ましく、０．３ｍ２／ｇが特に好ましい。一方で、その上限値は５０.０ｍ２／ｇが好ましく、４０.０ｍ２／ｇが特に好ましい。なお、上記した下限値、上限値は、任意で組み合わせることができる。The BET specific surface area of the positive electrode compound of the present invention is not particularly limited, but, for example, the lower limit is preferably 0.1 m 2 /g from the viewpoint of the balance between improving the density and ensuring a contact surface with the electrolytic solution. , 0.3 m 2 /g are particularly preferred. On the other hand, the upper limit is preferably 50.0 m 2 /g, particularly preferably 40.0 m 2 /g. In addition, the above-described lower limit value and upper limit value can be combined arbitrarily.

本発明の正極用化合物のタップ密度は、特に限定されないが、例えば、正極活物質として使用した際における充填度の向上の点から、１．５ｇ／ｃｍ３以上が好ましく、１．７ｇ／ｃｍ３以上が特に好ましい。The tap density of the positive electrode compound of the present invention is not particularly limited . The above are particularly preferred.

本発明の正極用化合物のバルク密度は、特に限定されないが、例えば、正極活物質として使用した際における充填度の向上の点から０．８ｇ／ｃｍ３以上が好ましく、１．０ｇ／ｃｍ３以上が特に好ましい。The bulk density of the positive electrode compound of the present invention is not particularly limited, but is preferably 0.8 g/cm 3 or more, and 1.0 g/cm 3 or more, for example, from the viewpoint of improving the filling degree when used as a positive electrode active material. is particularly preferred.

次に、本発明の正極用化合物の製造方法例について説明する。 Next, an example of the method for producing the positive electrode compound of the present invention will be described.

上記製造方法としては、例えば、先ず、核となる、ニッケル複合水酸化物粒子を調製する。ニッケル複合水酸化物粒子の調製方法は、先ず、共沈法により、ニッケルの塩溶液（例えば、硫酸塩溶液）またはニッケルと他の金属元素（例えば、コバルト、亜鉛、マンガン、リチウム、マグネシウム、アルミニウム、ジルコニウム、イットリウム、イッテルビウム及び／またはタングステン）の塩溶液（例えば、硫酸塩溶液）と錯化剤とを反応させて、ニッケル複合水酸化物粒子（例えば、水酸化ニッケル粒子、ニッケルと他の金属元素（例えば、コバルト、亜鉛、マンガン、リチウム、マグネシウム、アルミニウム、ジルコニウム、イットリウム、イッテルビウム及び／またはタングステン）とを含む水酸化物粒子）を調製して、ニッケル複合水酸化物粒子を含むスラリー状の懸濁物を得る。懸濁物の溶媒としては、例えば、水が使用される。 As the above production method, for example, first, nickel composite hydroxide particles that serve as nuclei are prepared. A method for preparing nickel composite hydroxide particles is to first prepare a nickel salt solution (e.g., sulfate solution) or nickel and other metal elements (e.g., cobalt, zinc, manganese, lithium, magnesium, aluminum) by a coprecipitation method. , zirconium, yttrium, ytterbium and/or tungsten) are reacted with a complexing agent to form nickel composite hydroxide particles (e.g. nickel hydroxide particles, nickel and other metal element (e.g., cobalt, zinc, manganese, lithium, magnesium, aluminum, zirconium, yttrium, ytterbium and/or tungsten)) is prepared to form a slurry containing nickel composite hydroxide particles; A suspension is obtained. Water, for example, is used as a solvent for the suspension.

上記錯化剤としては、水溶液中で、ニッケル及び上記他の金属元素のイオンと錯体を形成可能なものであれば、特に限定されず、例えば、アンモニウムイオン供給体（硫酸アンモニウム、塩化アンモニウム、炭酸アンモニウム、弗化アンモニウム等）、ヒドラジン、エチレンジアミン四酢酸、ニトリロ三酢酸、ウラシル二酢酸、及びグリシンが挙げられる。なお、沈殿に際しては、水溶液のｐＨ値を調整するため、必要に応じて、アルカリ金属水酸化物（例えば、水酸化ナトリウム、水酸化カリウム）を添加してもよい。 The complexing agent is not particularly limited as long as it can form a complex with ions of nickel and other metal elements in an aqueous solution. , ammonium fluoride, etc.), hydrazine, ethylenediaminetetraacetic acid, nitrilotriacetic acid, uracildiacetic acid, and glycine. In the precipitation, an alkali metal hydroxide (for example, sodium hydroxide, potassium hydroxide) may be added as necessary to adjust the pH value of the aqueous solution.

上記塩溶液に加えて、錯化剤を反応槽に連続して供給すると、ニッケル及び上記他の金属元素が反応し、ニッケル複合水酸化物粒子が調製される。反応に際しては、反応槽の温度を、例えば、１０℃～８０℃、好ましくは２０～７０℃の範囲内で制御し、反応槽内のｐＨ値を液温２５℃基準で、例えば、ｐＨ９～ｐＨ１３、好ましくはｐＨ１１～１３の範囲内で制御しつつ、反応槽内の物質を、適宜、撹拌する。反応槽としては、例えば、形成されたニッケル複合水酸化物粒子を分離するためにオーバーフローさせる、連続式を挙げることができる。 When the complexing agent is continuously supplied to the reactor in addition to the salt solution, nickel and the other metal elements react to prepare nickel composite hydroxide particles. During the reaction, the temperature of the reaction vessel is controlled, for example, within the range of 10° C. to 80° C., preferably 20° C. to 70° C., and the pH value in the reaction vessel is adjusted to a liquid temperature of 25° C., for example, pH 9 to pH 13. While controlling the pH preferably within the range of 11 to 13, the substances in the reaction vessel are appropriately stirred. The reactor can include, for example, a continuous type, overflowing to separate the formed nickel composite hydroxide particles.

次に、上記のようにして得られた、核となるニッケル複合水酸化物粒子に、パラジウム系触媒と界面活性剤を供給して、ニッケル複合水酸化物粒子表面にパラジウム系触媒を担持させる。その後、パラジウム系触媒を担持させたニッケル複合水酸化物粒子を、リン元素が含まれず主にニッケルからなるめっき液に浸漬させ、さらにヒドラジン系の添加剤を投入して無電解めっきを行って、ニッケル複合水酸化物粒子表面にニッケルをめっきする。無電解めっきにあたっては、被覆層のニッケル元素の含有量が核１００質量部に対して６質量部以上２０質量部以下となるように、膜厚及び／またはめっき液の組成を調整して、ニッケル複合水酸化物粒子表面にめっき膜を形成する。これにより、コバルト元素が５００ｐｐｍ以下及びリン元素が１０ｐｐｍ以下であるニッケル元素を含む被覆層を形成できる。 Next, a palladium-based catalyst and a surfactant are supplied to the core nickel composite hydroxide particles obtained as described above to support the palladium-based catalyst on the surfaces of the nickel composite hydroxide particles. After that, the nickel composite hydroxide particles supporting a palladium-based catalyst are immersed in a plating solution containing no phosphorus element and mainly composed of nickel, and a hydrazine-based additive is added to perform electroless plating. Nickel is plated on the surface of the nickel composite hydroxide particles. In the electroless plating, the film thickness and/or the composition of the plating solution are adjusted so that the content of the nickel element in the coating layer is 6 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the core. A plated film is formed on the surface of the composite hydroxide particles. This makes it possible to form a coating layer containing nickel with a cobalt content of 500 ppm or less and a phosphorus content of 10 ppm or less.

上記した無電解めっきを用いた被覆層の形成方法では、被覆層のニッケル元素の平均一次粒子径が１０ｎｍ以上１００ｎｍ以下の範囲となる。なお、ニッケル複合水酸化物粒子表面にパラジウム系触媒を担持させないと、被覆層のニッケル元素の平均一次粒子径が１００ｎｍ超に粗大化し、被覆層の表面が粗面化、粗化されて、１．５×１０Ω・ｃｍ以下の体積抵抗率が得られない。 In the above method of forming a coating layer using electroless plating, the average primary particle size of the nickel element in the coating layer is in the range of 10 nm or more and 100 nm or less. In addition, if a palladium-based catalyst is not supported on the surface of the nickel composite hydroxide particles, the average primary particle size of the nickel element in the coating layer is coarsened to more than 100 nm, and the surface of the coating layer is roughened and roughened. A volume resistivity of 5×10 Ω·cm or less cannot be obtained.

次に、本発明の正極用化合物を用いた正極について説明する。以下に、本発明の正極用化合物をニッケル水素二次電池等のアルカリ蓄電池や非水電解質二次電池の正極として用いる場合について説明する。正極は、正極集電体と、正極集電体表面に形成された、本発明の正極用化合物を含有する正極活物質層を備える。正極活物質層は、本発明の正極用化合物である正極活物質と、バインダー（結着剤）と、使用条件等に応じて少量の導電助剤と、を有する。上記の通り、本発明の正極用化合物は体積抵抗率が低いので、導電助剤を添加しなくても、正極に所定の導電性を付与することができる場合もある。導電助剤としては、例えば、畜電池（二次電池）のために使用できるものであれば、特に限定されないが、アセチレンブラック（ＡＢ）、金属コバルト、酸化コバルト等を用いることができる。バインダーとしては、特に限定されないが、ポリマー樹脂、例えば、ポリフッ化ビニリデン（ＰＶｄＦ）、ブタジエンゴム（ＢＲ）、ポリビニルアルコール（ＰＶＡ）、及びカルボキシメチルセルロース（ＣＭＣ）、ポリテトラフルオロエチレン（ＰＴＦＥ）等、並びにこれらの組み合わせを挙げることができる。正極集電体としては、特に限定されないが、パンチングメタル、エキスパンドメタル、金網、発泡金属、例えば発泡ニッケル、網状金属繊維焼結体、金属めっき樹脂板などを挙げることができる。 Next, a positive electrode using the compound for a positive electrode of the present invention will be described. A case where the positive electrode compound of the present invention is used as a positive electrode for an alkaline storage battery such as a nickel-hydrogen secondary battery or a non-aqueous electrolyte secondary battery will be described below. The positive electrode includes a positive electrode current collector and a positive electrode active material layer containing the positive electrode compound of the present invention formed on the surface of the positive electrode current collector. The positive electrode active material layer includes a positive electrode active material, which is the compound for a positive electrode of the present invention, a binder (binding agent), and a small amount of conductive aid depending on conditions of use and the like. As described above, since the positive electrode compound of the present invention has a low volume resistivity, it may sometimes be possible to impart predetermined conductivity to the positive electrode without adding a conductive aid. The conductive aid is not particularly limited as long as it can be used for storage batteries (secondary batteries), but acetylene black (AB), metallic cobalt, cobalt oxide, etc. can be used. Binders include, but are not limited to, polymer resins such as polyvinylidene fluoride (PVdF), butadiene rubber (BR), polyvinyl alcohol (PVA), carboxymethylcellulose (CMC), polytetrafluoroethylene (PTFE), and the like. Combinations of these can be mentioned. Examples of the positive electrode current collector include, but are not limited to, punching metal, expanded metal, wire mesh, foam metal such as nickel foam, sintered net-like metal fiber, and metal-plated resin plate.

ニッケル水素二次電池等のアルカリ蓄電池や非水電解質二次電池の正極の製造方法としては、例えば、先ず、本発明の正極用化合物と導電助剤と結着剤と水とを混合して正極活物質スラリーを調製する。次いで、上記正極活物質スラリーを正極集電体に、公知の充填方法で充填して乾燥後、プレス等にて圧延・固着することで正極を得ることができる。 As a method for producing a positive electrode for an alkaline storage battery such as a nickel-hydrogen secondary battery or a non-aqueous electrolyte secondary battery, for example, first, the positive electrode compound of the present invention, a conductive aid, a binder, and water are mixed to produce a positive electrode. An active material slurry is prepared. Then, the positive electrode current collector is filled with the positive electrode active material slurry by a known filling method, dried, and then rolled and fixed by a press or the like to obtain a positive electrode.

また、本発明の正極用化合物をリチウムイオン二次電池等の非水電解質二次電池の正極活物質の前駆体として用いる場合には、本発明の正極用化合物に炭酸リチウム、水酸化リチウム等のリチウム化合物を添加して、リチウム化合物と正極用化合物の混合物を得、得られた混合物を一次焼成（焼成温度は、例えば、６００℃～９００℃、焼成時間は、例えば、５時間～２０時間）、さらに二次焼成（焼成温度は、例えば、７００℃以上１０００℃以下、焼成時間は、例えば、１～２０時間）することで、リチウムイオン二次電池等の非水電解質二次電池の正極活物質を得ることができる。リチウムイオン二次電池等の非水電解質二次電池の正極は、正極集電体と、正極集電体表面に形成された、本発明の正極用化合物を前駆体として用いた正極活物質層を備える。正極活物質層は、本発明の正極用化合物を前駆体として用いた正極活物質と、バインダー（結着剤）と、必要に応じて導電助剤とを有する。正極集電体、バインダー、導電助剤としては、上記と同様のものを用いることができる。 When the positive electrode compound of the present invention is used as a precursor of the positive electrode active material of a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery, the positive electrode compound of the present invention may contain lithium carbonate, lithium hydroxide, or the like. A lithium compound is added to obtain a mixture of the lithium compound and the positive electrode compound, and the resulting mixture is first fired (the firing temperature is, for example, 600° C. to 900° C., and the firing time is, for example, 5 hours to 20 hours). , and further secondary firing (the firing temperature is, for example, 700 ° C. or higher and 1000 ° C. or lower, and the firing time is, for example, 1 to 20 hours) to make the positive electrode active in non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries. You can get the substance. The positive electrode of a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery includes a positive electrode current collector and a positive electrode active material layer formed on the surface of the positive electrode current collector and using the positive electrode compound of the present invention as a precursor. Prepare. The positive electrode active material layer has a positive electrode active material using the compound for a positive electrode of the present invention as a precursor, a binder (binding agent), and, if necessary, a conductive aid. As the positive electrode current collector, the binder, and the conductive aid, the same materials as those described above can be used.

リチウムイオン二次電池等の非水電解質二次電池の正極の製造方法としては、例えば、先ず、本発明の正極用化合物を前駆体として用いた正極活物質と導電助剤と結着剤とＮ－メチル－２－ピロリドン（ＮＭＰ）とを混合して正極活物質スラリーを調製する。次いで、上記正極活物質スラリーを正極集電体に、公知の充填方法で充填して乾燥後、プレス等にて圧延・固着することで正極を得ることができる。 As a method for producing a positive electrode of a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery, for example, first, a positive electrode active material using the positive electrode compound of the present invention as a precursor, a conductive aid, a binder, and N -methyl-2-pyrrolidone (NMP) to prepare a positive electrode active material slurry. Then, the positive electrode current collector is filled with the positive electrode active material slurry by a known filling method, dried, and then rolled and fixed by a press or the like to obtain a positive electrode.

上記のようにして得られた正極活物質を用いた正極と、負極集電体と負極集電体表面に形成された負極活物質を含む負極活物質層を備える負極と、所定の電解質と、セパレータとを、公知の方法で搭載することで蓄電池（例えば、アルカリ蓄電池、非水系電解質二次電池等）を組み上げることができる。 A positive electrode using the positive electrode active material obtained as described above, a negative electrode comprising a negative electrode current collector and a negative electrode active material layer containing the negative electrode active material formed on the surface of the negative electrode current collector, a predetermined electrolyte, A storage battery (for example, an alkaline storage battery, a non-aqueous electrolyte secondary battery, etc.) can be assembled by mounting a separator by a known method.

次に、本発明の実施例を説明するが、本発明はその趣旨を超えない限り、これらの例に限定されるものではない。 Examples of the present invention will now be described, but the present invention is not limited to these examples as long as the gist of the present invention is not exceeded.

実施例１～２の正極用化合物の製造方法
ニッケル複合水酸化物粒子の調製
攪拌機付きの反応槽に、硫酸ニッケルと硫酸コバルトと硫酸亜鉛とを所定比（ニッケル：コバルト：亜鉛＝９２．１：１．１２：６．７７の質量比）で溶解した水溶液に、硫酸アンモニウム水溶液と水酸化ナトリウム水溶液を滴下して反応容積５００Ｌの反応槽内で反応温度４５．０℃、液温４０℃基準で反応ｐＨ１２．１に維持しながら、攪拌回転数５２０ｒｐｍで攪拌羽根が２５０ｍｍのプロペラの攪拌機により連続的に攪拌した。生成した水酸化物は反応槽のオーバーフロー管からオーバーフローさせて取り出した。取り出した水酸化物に、水洗、脱水、乾燥の各処理を施して、核となるニッケル複合水酸化物粒子を得た。得られたニッケル複合水酸化物粒子の組成は、ニッケル元素の含有量が９２．１質量部、コバルト元素の含有量が１．１２質量部、亜鉛元素の含有量が６.７７質量部であることを誘導結合プラズマ発光分析装置にて確認した。Manufacturing method of positive electrode compound of Examples 1 and 2 Preparation of nickel composite hydroxide particles In a reaction vessel equipped with a stirrer, nickel sulfate, cobalt sulfate, and zinc sulfate were added at a predetermined ratio (nickel: cobalt: zinc = 92.1: 1.12:6.77 mass ratio), an aqueous solution of ammonium sulfate and an aqueous solution of sodium hydroxide are added dropwise to react at a reaction temperature of 45.0 ° C. and a liquid temperature of 40 ° C. in a reaction vessel with a reaction volume of 500 L. While maintaining the pH at 12.1, the mixture was continuously stirred with a propeller stirrer having a stirring blade of 250 mm at a stirring speed of 520 rpm. The hydroxide produced was overflowed from the overflow tube of the reactor and removed. The extracted hydroxide was washed with water, dehydrated, and dried to obtain nickel composite hydroxide particles serving as nuclei. The resulting nickel composite hydroxide particles have a nickel element content of 92.1 parts by mass, a cobalt element content of 1.12 parts by mass, and a zinc element content of 6.77 parts by mass. This was confirmed by an inductively coupled plasma emission spectrometer.

上記のようにして調製したニッケル複合水酸化物粒子に、直接、無電解純ニッケルめっき処理を施して、被覆層としてニッケルめっき膜を有するニッケル複合水酸化物、すなわち、ニッケル含有被覆ニッケル複合水酸化物を製造した。より詳細には、以下の通りに、ニッケルめっき膜を有するニッケル複合水酸化物を製造した。 The nickel composite hydroxide particles prepared as described above are directly subjected to electroless pure nickel plating treatment to obtain a nickel composite hydroxide having a nickel plating film as a coating layer, that is, a nickel-containing coated nickel composite hydroxide. manufactured things. More specifically, a nickel composite hydroxide having a nickel plating film was produced as follows.

先ず、粒子径１０μｍのニッケル複合水酸化物粒子を基材粒子として、基材粒子表面を改質するために、基材粒子をカチオン系界面活性剤で、１０分間撹拌処理した。その後、ろ過水洗してから、パラジウムイオン触媒溶液で、１０分間撹拌処理して、基材粒子表面にパラジウムイオンを吸着させた。その後、ろ過水洗してから、還元溶液で、１０分間撹拌処理して、基材粒子表面にパラジウム触媒を担持させた。その後、ろ過水洗してから、８０℃に加温した硫酸ニッケル溶液中にて、表面にパラジウム触媒を担持させた基材粒子を１分間予備撹拌した。なお、硫酸ニッケル溶液の組成は、ニッケル塩０．３０ｍｏｌ／Ｌ、クエン酸塩１ｍｏｌ／Ｌ、炭酸塩１．７ｍｏｌ／Ｌとした。その後、ヒドラジン一水和物を０．４ｍｏｌ／Ｌの量で硫酸ニッケル溶液に投入した。反応開始後、表面にパラジウム触媒を担持させた基材粒子を、５分間以上、ヒドラジン一水和物を投入した硫酸ニッケル溶液中にて撹拌して、ニッケル複合水酸化物粒子表面にニッケルめっき膜を形成させていき、ニッケル元素を含む被覆層を形成させた。撹拌後、ニッケル元素を含む被覆層を形成させたニッケル複合水酸化物粒子をろ過水洗し、８０℃で乾燥させた。このようにして、本発明に係る正極用化合物であるニッケル含有被覆ニッケル複合水酸化物粒子を得た。なお、ニッケル複合水酸化物粒子１００質量部に対する被覆層のニッケル元素の含有量（７．５質量部、１０質量部）は、硫酸ニッケル液の投入量を調節することで調整した。 First, nickel composite hydroxide particles having a particle diameter of 10 μm were used as base particles, and the base particles were subjected to stirring treatment with a cationic surfactant for 10 minutes in order to modify the surface of the base particles. Then, after filtering and washing with water, a palladium ion catalyst solution was added to the substrate particles and stirred for 10 minutes to adsorb palladium ions on the surfaces of the substrate particles. Then, after filtering and washing with water, the substrate particles were stirred for 10 minutes with a reducing solution to support the palladium catalyst on the surfaces of the substrate particles. Thereafter, after being filtered and washed with water, the substrate particles having a palladium catalyst supported on their surfaces were pre-stirred for 1 minute in a nickel sulfate solution heated to 80°C. The composition of the nickel sulfate solution was 0.30 mol/L nickel salt, 1 mol/L citrate, and 1.7 mol/L carbonate. Hydrazine monohydrate was then introduced into the nickel sulfate solution in an amount of 0.4 mol/L. After the start of the reaction, the base particles having the palladium catalyst supported on their surfaces are stirred for 5 minutes or longer in a nickel sulfate solution containing hydrazine monohydrate to form a nickel plating film on the surfaces of the nickel composite hydroxide particles. was formed to form a coating layer containing nickel element. After stirring, the nickel composite hydroxide particles on which a coating layer containing nickel element was formed were filtered, washed with water, and dried at 80°C. Thus, nickel-containing coated nickel composite hydroxide particles, which are the positive electrode compound according to the present invention, were obtained. The nickel element content (7.5 parts by mass, 10 parts by mass) of the coating layer with respect to 100 parts by mass of the nickel composite hydroxide particles was adjusted by adjusting the input amount of the nickel sulfate solution.

比較例１の正極用化合物の製造方法
上記実施例と同様にして、核となるニッケル複合水酸化物粒子を得た。その後、核となるニッケル複合水酸化物粒子を、水酸化ナトリウムにて液温５０℃基準でｐＨ９．０に維持した反応浴中のアルカリ水溶液に投入した。投入後、該溶液を撹拌しながら、濃度９０ｇ／Ｌの硫酸コバルト水溶液を滴下した。この間、水酸化ナトリウム水溶液を適宜滴下して、液温５０℃基準で反応浴をｐＨ９．０に維持しながら１時間保持することで、ニッケル複合水酸化物粒子（核）の表面に水酸化コバルトからなる被覆層を形成させた、水酸化コバルト被覆ニッケル複合水酸化物粒子を得た。なお、被覆されたコバルトの含有量は、ニッケル複合水酸化物粒子１００質量部に対して２．６質量部であった。Method for Producing Positive Electrode Compound of Comparative Example 1 Nickel composite hydroxide particles serving as cores were obtained in the same manner as in the above example. Thereafter, the core nickel composite hydroxide particles were put into an alkaline aqueous solution in a reaction bath maintained at a pH of 9.0 with sodium hydroxide at a liquid temperature of 50°C. After the injection, an aqueous cobalt sulfate solution with a concentration of 90 g/L was added dropwise while stirring the solution. During this time, an aqueous sodium hydroxide solution is added dropwise as appropriate, and the reaction bath is maintained at a pH of 9.0 at a liquid temperature of 50° C. for 1 hour. Cobalt hydroxide-coated nickel composite hydroxide particles were obtained in which a coating layer consisting of was formed. The content of coated cobalt was 2.6 parts by mass with respect to 100 parts by mass of the nickel composite hydroxide particles.

その後、容積が２５Ｌのハイスピードミキサー（深江パウテック株式会社製、型式ＦＭＤ－２５Ｊ）に、得られた水酸化コバルト被覆ニッケル複合水酸化物粒子を７Ｋｇ投入した。その後、空気を撹拌混合装置の導入口から撹拌混合装置内へ導入し排気口から排気しながら、撹拌混合装置底部の主攪拌羽を回転数２００ｒｐｍで、撹拌混合装置側壁の副攪拌羽を１２００ｒｐｍで、それぞれ回転させて水酸化コバルト被覆ニッケル複合水酸化物粒子を混合した。混合を継続しながら、加熱ジャケットで加熱させて撹拌混合装置内のサンプルの温度がほぼ９０℃となった後、撹拌混合装置内に４８質量％水酸化ナトリウム水溶液０．４Ｌを、約２分間、噴霧装置から噴霧した。噴霧終了後、約３０分間は撹拌混合装置内の温度は約１２０℃まで昇温し、粒子の表面の色が薄いピンク色から黒色に変化した。その後、撹拌混合装置内の温度を室温に戻し、生成物粒子を取り出し、取り出した生成物粒子を水で洗浄した後、空気中で加熱乾燥した。このようにして比較例１の正極用化合物であるＣｏＯＯＨ被覆ニッケル複合水酸化物粒子を得た。 After that, 7 kg of the obtained cobalt hydroxide-coated nickel composite hydroxide particles were put into a 25-liter high-speed mixer (manufactured by Fukae Powtech Co., Ltd., model FMD-25J). After that, while introducing air into the stirring and mixing device from the inlet of the stirring and mixing device and exhausting it from the exhaust port, the main stirring blade on the bottom of the stirring and mixing device was rotated at 200 rpm, and the auxiliary stirring blade on the side wall of the stirring and mixing device was rotated at 1200 rpm. , respectively, to mix the cobalt hydroxide-coated nickel composite hydroxide particles. While continuing to mix, the temperature of the sample in the stirring and mixing device was heated by the heating jacket to reach approximately 90°C, and then 0.4 L of a 48% by mass sodium hydroxide aqueous solution was added to the stirring and mixing device for about 2 minutes. Nebulized from the nebulizer. After completion of spraying, the temperature in the stirring and mixing device increased to about 120° C. for about 30 minutes, and the surface color of the particles changed from pale pink to black. Thereafter, the temperature inside the stirring and mixing device was returned to room temperature, the product particles were taken out, washed with water, and then dried by heating in the air. Thus, CoOOH-coated nickel composite hydroxide particles, which are the positive electrode compound of Comparative Example 1, were obtained.

比較例２～４の正極用化合物の製造方法
上記実施例と同様にして、核となるニッケル複合水酸化物粒子を得た。その後、平均粒径１０μｍのニッケル複合水酸化物粒子に対して、無電解ニッケルめっきを施した。無電解めっき浴としては、以下に示す組成を有するものを用いた。
硫酸ニッケル２２．０ｇ／Ｌ
グリシン３３．３ｇ／Ｌ
次亜リン酸ナトリウム２３．３ｇ／Ｌ
水酸化ナトリウム１２．３ｇ／Ｌ
界面活性剤１０ｍＬ／Ｌ
ｐＨ９．５Method for Producing Positive Electrode Compounds of Comparative Examples 2 to 4 In the same manner as in the above Examples, nickel composite hydroxide particles serving as nuclei were obtained. After that, electroless nickel plating was applied to nickel composite hydroxide particles having an average particle size of 10 μm. As the electroless plating bath, one having the composition shown below was used.
Nickel sulfate 22.0g/L
Glycine 33.3 g/L
Sodium hypophosphite 23.3g/L
Sodium hydroxide 12.3g/L
Surfactant 10mL/L
pH 9.5

以上の条件を満たす３Ｌのめっき浴を６０℃で建浴し、ニッケル複合水酸化物粒子５０ｇを、直接、投入した。すなわち、浸漬脱脂工程、表面調整工程及びエッチング工程などの前処理工程は、一切行わなかった。ニッケル複合水酸化物粒子を投入した後、毎分５００回転の速度でプロペラ撹拌を１０分間行い、そこへ塩化パラジウム及び塩酸を主成分とする溶液（アクチベーター、塩化パラジウム濃度２ｇ／Ｌ）を２０ｍＬ投入した。この投入とともに、瞬時に発泡が始まり、パラジウムイオンの還元及びニッケルめっきが進行し始めた。発泡が終了するまでの約３０分間、毎分５００回転の速度でプロペラ撹拌を継続し、発泡終了後、撹拌を停止した。吸引ろ過器を用いてろ過した後、水洗を３回繰り返した後、８０℃で１時間、温風で乾燥した。このようにして、比較例２～４の正極用化合物である、ニッケル－リン複合めっき膜で被覆されたニッケル複合水酸化物粒子を得た。なお、ニッケル複合水酸化物粒子１００質量部に対する被覆層のニッケル元素の含有量は、硫酸ニッケル液の投入量を調節することで調整した。 A 3 L plating bath satisfying the above conditions was prepared at 60° C., and 50 g of nickel composite hydroxide particles were directly added. That is, no pretreatment steps such as immersion degreasing, surface conditioning, and etching were performed. After charging the nickel composite hydroxide particles, propeller stirring was performed at a speed of 500 rpm for 10 minutes, and 20 mL of a solution containing palladium chloride and hydrochloric acid as main components (activator, palladium chloride concentration: 2 g/L) was added. put in. With this charging, bubbling started instantaneously, and reduction of palladium ions and nickel plating began to progress. Propeller stirring was continued at a speed of 500 rpm for about 30 minutes until foaming was completed, and stirring was stopped after foaming was completed. After filtration using a suction filter, washing with water was repeated three times, followed by drying with hot air at 80° C. for 1 hour. In this way, nickel composite hydroxide particles coated with a nickel-phosphorus composite plating film, which are positive electrode compounds of Comparative Examples 2 to 4, were obtained. The content of the nickel element in the coating layer with respect to 100 parts by mass of the nickel composite hydroxide particles was adjusted by adjusting the input amount of the nickel sulfate liquid.

比較例５の正極用化合物の製造方法
硫酸ニッケル液の投入量を調節することで、ニッケル複合水酸化物粒子１００質量部に対する被覆層のニッケル元素の含有量を５．０質量部に調整したこと以外は、上記実施例１～２の製造方法と同様にして比較例５の正極用化合物を製造した。Method for producing a positive electrode compound of Comparative Example 5 By adjusting the input amount of the nickel sulfate solution, the content of the nickel element in the coating layer was adjusted to 5.0 parts by mass with respect to 100 parts by mass of the nickel composite hydroxide particles. A positive electrode compound of Comparative Example 5 was produced in the same manner as in Examples 1 and 2 except for the above.

実施例１～２、比較例５のニッケル複合水酸化物粒子１００質量部に対する被覆層のニッケル元素の含有量、比較例１のニッケル複合水酸化物粒子１００質量部に対する被覆層のコバルト元素の含有量、比較例２～４のニッケル複合水酸化物粒子１００質量部に対する被覆層のニッケル元素の含有量について、下記表１に示す。 Examples 1 and 2, the content of the nickel element in the coating layer relative to 100 parts by mass of the nickel composite hydroxide particles of Comparative Example 5, the content of the cobalt element in the coating layer relative to 100 parts by mass of the nickel composite hydroxide particles of Comparative Example 1 Table 1 below shows the amount and the content of the nickel element in the coating layer with respect to 100 parts by mass of the nickel composite hydroxide particles of Comparative Examples 2 to 4.

評価項目は以下の通りである。
（１）組成分析
実施例１～２及び比較例２～５で得られたニッケル複合水酸化物粉末の組成分析は、得られた粉末を塩酸もしくは王水に溶解させた後、誘導結合プラズマ発光分析装置（株式会社パーキンエルマージャパン製、７３００ＤＶ）を用いて行った。
（２）体積抵抗率
体積抵抗率は、ロレスター抵抗率計（三菱化学社製、ＭＣＰ－Ｔ６１０）及びハイレスター抵抗率計（三菱化学社製、ＭＣＰ－ＨＴ４５０）で測定し、荷重２０ｋＮ時の体積抵抗率を求めた。以下により測定条件を示す。
ロレスター抵抗率計
測定方式：オートレンジ方式、印加電圧１０Ｖ、荷重２０ｋＮ、試料重量１．５ｇ
ハイレスター抵抗率計
測定方式：オートレンジ方式、印加電圧１０Ｖ、荷重２０ｋＮ、試料重量１．５ｇEvaluation items are as follows.
(1) Composition analysis The composition analysis of the nickel composite hydroxide powders obtained in Examples 1 and 2 and Comparative Examples 2 and 5 was performed by dissolving the obtained powders in hydrochloric acid or aqua regia, followed by inductively coupled plasma emission. It was carried out using an analyzer (7300DV, manufactured by PerkinElmer Japan Co., Ltd.).
(2) Volume resistivity Volume resistivity is measured with a Lorestar resistivity meter (Mitsubishi Chemical Co., MCP-T610) and a Hiresta resistivity meter (Mitsubishi Chemical Co., MCP-HT450). Resistivity was determined. Measurement conditions are shown below.
Lorestar resistivity meter measurement method: auto range method, applied voltage 10 V, load 20 kN, sample weight 1.5 g
Hiresta resistivity meter measurement method: auto range method, applied voltage 10 V, load 20 kN, sample weight 1.5 g

（３）利用率（初期）
ニッケル水素電池を、２５℃の環境温度で、０．２Ｃの充電率で６時間充電した後、２５℃の環境温度で０．５時間放置し、その後、２５℃の環境温度で０．２Ｃの放電率で１．０Ｖまで放電した。このような充放電を、１２サイクル繰り返し、１２サイクル目の放電容量を求めた。得られた１２サイクル目の放電容量を元に、次式により利用率を求めた。
利用率（％）＝１２サイクル目の放電容量（ｍＡｈ）／理論容量（ｍＡｈ）×１００
（４）利用率（９０℃で６日間放置後）
ニッケル水素電池を、２５℃の環境温度で、０．２Ｃの充電率で６時間充電した後、２５℃の環境温度で０．５時間放置し、その後、２５℃の環境温度で０．２Ｃの放電率で１．０Ｖまで放電した。その後０．２Ｃの深放電試験を実施した後に、無負荷接続状態にて９０℃で６日間の自然放置することにより、ニッケル水素電池を放電した。その後２５℃の環境温度で、０．２Ｃの充電率で６時間充電した後、２５℃の環境温度で０．５時間放置し、２５℃の環境温度で０．２Ｃの放電率で１．０Ｖまで放電した。このような充放電を２サイクル繰り返し、２サイクル目の放電容量を求めた。得られた２サイクル目の放電容量を元に、次式により利用率を求めた。
利用率（％）＝２サイクル目の放電容量（ｍＡｈ）／理論容量（ｍＡｈ）×１００
（５）ニッケル元素を含む被覆層の平均一次粒子径
ニッケル元素を含む被覆層の平均一次粒子径は、電界放出形走査電子顕微鏡（ＦＥ－ＳＥＭ）にて被覆層を観察した画像から、独立して存在している一次粒子をランダムに１０個選択し、選択した上記一次粒子の最長直径の部位を、それぞれ測定し、その平均値を平均一次粒子径とした。(3) Utilization rate (initial)
The nickel-metal hydride battery was charged at an environmental temperature of 25°C at a charging rate of 0.2C for 6 hours, then left at an environmental temperature of 25°C for 0.5 hours, and then charged at an environmental temperature of 25°C at a charging rate of 0.2C. It was discharged to 1.0 V at a discharge rate. Such charging and discharging was repeated for 12 cycles, and the discharge capacity at the 12th cycle was determined. Based on the obtained discharge capacity at the 12th cycle, the utilization rate was determined by the following equation.
Utilization rate (%) = 12th cycle discharge capacity (mAh) / theoretical capacity (mAh) x 100
(4) Utilization rate (after standing at 90°C for 6 days)
The nickel-metal hydride battery was charged at an environmental temperature of 25°C at a charging rate of 0.2C for 6 hours, then left at an environmental temperature of 25°C for 0.5 hours, and then charged at an environmental temperature of 25°C at a charging rate of 0.2C. It was discharged to 1.0 V at a discharge rate. After a deep discharge test at 0.2 C, the nickel-metal hydride battery was discharged by allowing it to stand at 90° C. for 6 days in a no-load connection state. After that, the battery was charged at an environmental temperature of 25°C at a charging rate of 0.2C for 6 hours, then left at an environmental temperature of 25°C for 0.5 hours, and discharged at an environmental temperature of 25°C at a discharge rate of 0.2C to 1.0V. discharged up to Such charging and discharging were repeated for two cycles, and the discharge capacity at the second cycle was obtained. Based on the obtained discharge capacity at the second cycle, the utilization rate was determined by the following formula.
Utilization rate (%) = second cycle discharge capacity (mAh) / theoretical capacity (mAh) x 100
(5) Average primary particle size of coating layer containing nickel element The average primary particle size of the coating layer containing nickel element is independent from the image of the coating layer observed with a field emission scanning electron microscope (FE-SEM). 10 primary particles were randomly selected, and the longest diameter portions of the selected primary particles were measured, and the average value was taken as the average primary particle size.

実施例１～２及び比較例２～５において、核であるニッケル複合水酸化物粒子にニッケル元素を含む被覆層が形成されていることは、核であるニッケル複合水酸化物粒子及び最終生成物であるニッケル含有被覆ニッケル複合水酸化物粒子の断面について、その中心部から表面部にわたって略等間隔に、それぞれ、エネルギー分散型Ｘ線分析（ＥＤＸ）にて組成分析することで確認した。すなわち、下記表２に示すように、核では、核中心部と核表面部でニッケル量に大きな変化がないのに対し、ニッケル含有被覆ニッケル複合水酸化物粒子では、粒子中心部と粒子表面部とでニッケル量に大きな変化があり、粒子表面部が粒子中心部よりもニッケル量が顕著に大きい（表２の下線で示すニッケル量）。このことから、核であるニッケル複合水酸化物粒子にニッケル元素を含む被覆層が形成されていることが確認できた。 In Examples 1 and 2 and Comparative Examples 2 and 5, the formation of a coating layer containing a nickel element on the nickel composite hydroxide particles that are the nuclei means that the nickel composite hydroxide particles that are the nuclei and the final product The cross section of the nickel-containing coated nickel composite hydroxide particles was confirmed by analyzing the composition by energy dispersive X-ray analysis (EDX) at approximately equal intervals from the center to the surface. That is, as shown in Table 2 below, in the core, there is no significant change in the amount of nickel between the core center and the core surface. There is a large change in the amount of nickel between the two, and the amount of nickel in the surface portion of the grain is significantly larger than that in the center portion of the grain (the amount of nickel indicated by the underline in Table 2). From this, it was confirmed that a coating layer containing nickel element was formed on the core nickel composite hydroxide particles.

評価結果を下記表１に示す。 The evaluation results are shown in Table 1 below.

Figure 0007290625000001
Figure 0007290625000001

Figure 0007290625000002
Figure 0007290625000002

なお、実施例１～２及び比較例２～５では、被覆層の形成にあたり、コバルト元素を添加していないことから、実施例１～２及び比較例２～５では、被覆層のコバルトの含有量は無し（０ｐｐｍ）、と判断できる。 In Examples 1 and 2 and Comparative Examples 2 and 5, no cobalt element was added in forming the coating layer. It can be judged that there is no amount (0 ppm).

上記表１に示すように、ニッケル複合水酸化物粒子の表面にコバルト元素が０ｐｐｍ及びリン元素が２ｐｐｍ以下であるニッケル元素を含む被覆層を有し、該被覆層のニッケル元素の含有量がニッケル複合水酸化物粒子１００質量部に対して７．０質量部以上１０質量部以下である実施例１～２では、体積抵抗率が０．０１５４Ω・ｃｍ以下、初期特性の利用率８７．９％以上、９０℃、６日目における利用率が８１．４％以上であった。従って、実施例１～２では、初期特性の利用率だけではなく高温放置後における利用率にも優れ、高い導電性を有する正極用化合物を得ることができた。特に、被覆層のニッケル元素の含有量がニッケル複合水酸化物粒子１００質量部に対して１０質量部である実施例１では、高温放置後における利用率と導電性がさらに向上した。 As shown in Table 1 above, the surface of the nickel composite hydroxide particles has a coating layer containing a nickel element having a cobalt element of 0 ppm and a phosphorus element of 2 ppm or less, and the content of the nickel element in the coating layer is nickel. In Examples 1 and 2 in which the content is 7.0 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the composite hydroxide particles, the volume resistivity is 0.0154 Ω cm or less, and the utilization rate of the initial characteristics is 87.9%. As described above, the utilization rate at 90° C. on the 6th day was 81.4% or more. Therefore, in Examples 1 and 2, it was possible to obtain a positive electrode compound having high electrical conductivity, not only in terms of the utilization rate of the initial characteristics, but also in the utilization rate after being left at a high temperature. In particular, in Example 1 in which the content of the nickel element in the coating layer was 10 parts by mass with respect to 100 parts by mass of the nickel composite hydroxide particles, the utilization rate and electrical conductivity after standing at a high temperature were further improved.

また、実施例１～２から、正極用化合物の体積抵抗率の低下に伴い、初期特性の利用率及び高温放置後における利用率が向上する傾向が確認できた。さらに、実施例１～２は比較例２～４と比較して、ニッケル元素を含む被覆層の平均一次粒子径が８１ｎｍ～８３ｎｍに微細化されていた。 Further, from Examples 1 and 2, it was confirmed that the utilization rate of the initial characteristics and the utilization rate after being left at a high temperature tended to improve as the volume resistivity of the positive electrode compound decreased. Furthermore, in Examples 1 and 2, compared with Comparative Examples 2 and 4, the average primary particle diameter of the nickel element-containing coating layer was reduced to 81 nm to 83 nm.

一方で、ＣｏＯＯＨ被覆されたニッケル複合水酸化物粒子である比較例１では、体積抵抗率が１５．３Ω・ｃｍであり、９０℃、６日目における利用率が７７．１％にとどまった。従って、比較例１では、導電性と高温放置後における良好な利用率とを得ることができなかった。 On the other hand, in Comparative Example 1, which is CoOOH-coated nickel composite hydroxide particles, the volume resistivity was 15.3 Ω·cm, and the utilization rate was only 77.1% at 90° C. on the 6th day. Therefore, in Comparative Example 1, it was not possible to obtain good conductivity and good utilization after being left at a high temperature.

また、ニッケル元素を含む被覆層中にリン元素が１５７０ｐｐｍ～２３２７ｐｐｍ含まれる比較例２～４では、体積抵抗率が６．２Ω・ｃｍ～２１．１Ω・ｃｍであるものの、初期特性の利用率７１．７％～７６．４％、高温放置後における利用率６６．６％～７１．０％と、いずれの利用率も大きく低下してしまった。また、ニッケル複合水酸化物粒子１００質量部に対する被覆層のニッケル元素の含有量が５．０質量部である比較例５では、体積抵抗率が上昇し、導電性が得られなかった。 In addition, in Comparative Examples 2 to 4 in which the coating layer containing the nickel element contained 1570 ppm to 2327 ppm of the phosphorus element, the volume resistivity was 6.2 Ω cm to 21.1 Ω cm, but the initial characteristic utilization rate was 71. Both of the utilization rates decreased significantly, from 7% to 76.4%, and from 66.6% to 71.0% after being left at a high temperature. In addition, in Comparative Example 5 in which the content of the nickel element in the coating layer was 5.0 parts by mass with respect to 100 parts by mass of the nickel composite hydroxide particles, the volume resistivity was increased and electrical conductivity was not obtained.

次に、実施例３、４、比較例６、７の正極用化合物の製造方法について説明する。 Next, methods for producing the positive electrode compounds of Examples 3 and 4 and Comparative Examples 6 and 7 will be described.

比較例７の正極用化合物の製造方法
攪拌機及びオーバーフローパイプを備えた反応槽内に水を入れた後、水酸化ナトリウム水溶液を添加した。硫酸ニッケル水溶液と硫酸コバルト水溶液と硫酸マンガン水溶液とを、ニッケル原子とコバルト原子とマンガン原子との原子比が０．５０：０．２０：０．３０となるように混合して、混合原料液を調製した。次に、反応槽内に、攪拌下、この混合原料溶液と硫酸アンモニウム水溶液を錯化剤として連続的に添加し、反応槽内の溶液のｐＨが液温４０℃基準で１１．３になるよう水酸化ナトリウム水溶液を適時滴下し、ニッケル複合水酸化物粒子であるニッケルコバルトマンガン複合水酸化物粒子を得た。得られたニッケル複合水酸化物粒子を、濾過後水洗し、１０５℃で乾燥することにより、比較例７のニッケル複合水酸化物の乾燥粉末を得た。Manufacturing Method of Positive Electrode Compound of Comparative Example 7 After water was put into a reactor equipped with a stirrer and an overflow pipe, an aqueous sodium hydroxide solution was added. An aqueous solution of nickel sulfate, an aqueous solution of cobalt sulfate, and an aqueous solution of manganese sulfate are mixed so that the atomic ratio of nickel atoms, cobalt atoms, and manganese atoms is 0.50:0.20:0.30 to form a mixed raw material solution. prepared. Next, this mixed raw material solution and an aqueous solution of ammonium sulfate are continuously added as a complexing agent into the reaction vessel while stirring, and water is added so that the pH of the solution in the reaction vessel becomes 11.3 based on the liquid temperature of 40°C. An aqueous sodium oxide solution was added dropwise at appropriate times to obtain nickel-cobalt-manganese composite hydroxide particles, which are nickel composite hydroxide particles. The obtained nickel composite hydroxide particles were filtered, washed with water, and dried at 105° C. to obtain dry powder of nickel composite hydroxide of Comparative Example 7.

実施例３の正極用化合物の製造方法
上記のようにして調製した比較例７のニッケル複合水酸化物粒子に、さらに、直接、無電解純ニッケルめっき処理を施して、実施例３の、被覆層としてニッケルめっき膜を有するニッケル複合水酸化物（被覆層としてニッケルめっき膜を有するニッケルコバルトマンガン複合水酸化物）、すなわち、ニッケル含有被覆ニッケル複合水酸化物を製造した。より詳細には、以下の通りに、ニッケルめっき膜を有するニッケル複合水酸化物を製造した。Method for producing the positive electrode compound of Example 3 The nickel composite hydroxide particles of Comparative Example 7 prepared as described above were further directly subjected to electroless pure nickel plating treatment to form the coating layer of Example 3. A nickel composite hydroxide having a nickel plating film as a coating layer (nickel-cobalt-manganese composite hydroxide having a nickel plating film as a coating layer), that is, a nickel-containing coated nickel composite hydroxide was produced. More specifically, a nickel composite hydroxide having a nickel plating film was produced as follows.

先ず、粒子径１０μｍのニッケル複合水酸化物粒子を基材粒子として、基材粒子表面を改質するために、基材粒子をカチオン系界面活性剤、１０分間撹拌処理した。その後、ろ過水洗してから、パラジウムイオン触媒溶液で、１０分間撹拌処理して、基材粒子表面にパラジウムイオンを吸着させた。その後、ろ過水洗してから、還元溶液で、１０分間撹拌処理して、基材粒子表面にパラジウム触媒を担持させた。その後、ろ過水洗してから、８０℃に加温した硫酸ニッケル溶液中にて、表面にパラジウム触媒を担持させた基材粒子を１分間予備撹拌した。なお、硫酸ニッケル溶液の組成は、ニッケル塩０．３０ｍｏｌ／Ｌ、クエン酸塩１ｍｏｌ／Ｌ、炭酸塩１．７ｍｏｌ／Ｌとした。その後、ヒドラジン一水和物を０．４ｍｏｌ／Ｌの量で硫酸ニッケル溶液に投入した。反応開始後、表面にパラジウム触媒を担持させた基材粒子を、５分間以上、ヒドラジン一水和物を投入した硫酸ニッケル溶液中にて撹拌して、ニッケル複合水酸化物粒子表面にニッケルめっき膜を形成させていき、ニッケル元素を含む被覆層を形成させた。撹拌後、ニッケル元素を含む被覆層を形成させたニッケル複合水酸化物粒子をろ過水洗し、８０℃で乾燥させた。このようにして、本発明に係る正極用化合物であるニッケル含有被覆ニッケル複合水酸化物粒子を得た。なお、ニッケル複合水酸化物粒子１００質量部に対する被覆層のニッケル元素の含有量（１０質量部）は、硫酸ニッケル液の投入量を調節することで調整した。 First, nickel composite hydroxide particles having a particle diameter of 10 μm were used as base particles, and the base particles were treated with a cationic surfactant with stirring for 10 minutes in order to modify the surface of the base particles. Then, after filtering and washing with water, a palladium ion catalyst solution was added to the substrate particles and stirred for 10 minutes to adsorb palladium ions on the surfaces of the substrate particles. Then, after filtering and washing with water, the substrate particles were stirred for 10 minutes with a reducing solution to support the palladium catalyst on the surfaces of the substrate particles. Thereafter, after being filtered and washed with water, the substrate particles having a palladium catalyst supported on their surfaces were pre-stirred for 1 minute in a nickel sulfate solution heated to 80°C. The composition of the nickel sulfate solution was 0.30 mol/L nickel salt, 1 mol/L citrate, and 1.7 mol/L carbonate. Hydrazine monohydrate was then introduced into the nickel sulfate solution in an amount of 0.4 mol/L. After the start of the reaction, the base particles having the palladium catalyst supported on their surfaces are stirred for 5 minutes or longer in a nickel sulfate solution containing hydrazine monohydrate to form a nickel plating film on the surfaces of the nickel composite hydroxide particles. was formed to form a coating layer containing nickel element. After stirring, the nickel composite hydroxide particles on which a coating layer containing nickel element was formed were filtered, washed with water, and dried at 80°C. Thus, nickel-containing coated nickel composite hydroxide particles, which are the positive electrode compound according to the present invention, were obtained. The nickel element content (10 parts by mass) of the coating layer with respect to 100 parts by mass of the nickel composite hydroxide particles was adjusted by adjusting the input amount of the nickel sulfate solution.

実施例４の正極用化合物の製造方法
以上のようにして得られた実施例３のニッケル含有被覆ニッケル複合水酸化物の乾燥粉末と炭酸リチウム粉末とをＬｉ／（Ｎｉ＋Ｃｏ＋Ｍｎ）＝１．０３となるように秤量して混合した後、大気雰囲気下７４０℃で８．４時間一次焼成して、リチウム－ニッケル含有被覆ニッケル複合酸化物を一次焼成粉末として得た。その後、一次焼成粉末を粉砕し、大気雰囲気下９４０℃で８．４時間二次焼成して、実施例４のリチウム－ニッケル含有被覆ニッケル複合酸化物を二次焼成粉末として得た。Method for producing a positive electrode compound of Example 4 The dry powder of the nickel-containing coated nickel composite hydroxide of Example 3 obtained as described above and the lithium carbonate powder are Li/(Ni + Co + Mn) = 1.03. After weighing and mixing as described above, primary firing was performed at 740° C. for 8.4 hours in an air atmosphere to obtain a lithium-nickel-containing coated nickel composite oxide as a primary firing powder. Thereafter, the primary fired powder was pulverized and secondary fired at 940° C. for 8.4 hours in an air atmosphere to obtain the lithium-nickel-containing coated nickel composite oxide of Example 4 as a secondary fired powder.

比較例６の正極用化合物の製造方法
比較例７のニッケル複合水酸化物の乾燥粉末と炭酸リチウム粉末とをＬｉ／（Ｎｉ＋Ｃｏ＋Ｍｎ）＝１．０３となるように秤量して混合した後、大気雰囲気下７４０℃で８．４時間一次焼成して、リチウム－ニッケル複合酸化物を一次焼成粉末として得た。その後、一次焼成粉末を粉砕し、大気雰囲気下９４０℃で８．４時間二次焼成して、比較例６のリチウム－ニッケル複合酸化物を二次焼成粉末として得た。Method for producing a positive electrode compound of Comparative Example 6 After weighing and mixing the dry powder of the nickel composite hydroxide of Comparative Example 7 and the lithium carbonate powder so that Li / (Ni + Co + Mn) = 1.03, the mixture was mixed in an air atmosphere. After primary firing at 740° C. for 8.4 hours, a lithium-nickel composite oxide was obtained as a primary fired powder. Thereafter, the primary fired powder was pulverized and secondary fired at 940° C. for 8.4 hours in an air atmosphere to obtain a lithium-nickel composite oxide of Comparative Example 6 as a secondary fired powder.

評価項目は以下の通りである。
（１）組成分析
実施例４及び比較例６で得られた正極用化合物粉末の組成分析は、得られた粉末を塩酸もしくは王水に溶解させた後、誘導結合プラズマ発光分析装置（株式会社パーキンエルマージャパン社製、７３００ＤＶ）を用いて行った。
（２）体積抵抗率
体積抵抗率は、ロレスター抵抗率計（三菱化学製、ＭＣＰ－Ｔ６１０）及びハイレスター抵抗率計（三菱化学製、ＭＣＰ－ＨＴ４５０）で測定し、荷重２０ｋＮ時の体積抵抗率を求めた。以下により測定条件を示す。
ロレスター抵抗率計
測定方式：オートレンジ方式、印加電圧１０Ｖ、荷重２０ｋＮ、試料重量１．５ｇ
ハイレスター抵抗率計
測定方式：オートレンジ方式、印加電圧１０Ｖ、荷重２０ｋＮ、試料重量１．５ｇEvaluation items are as follows.
(1) Composition analysis The composition analysis of the positive electrode compound powders obtained in Example 4 and Comparative Example 6 was performed by dissolving the obtained powders in hydrochloric acid or aqua regia, followed by an inductively coupled plasma emission spectrometer (Perkin Co., Ltd.). 7300DV (manufactured by Elmer Japan) was used.
(2) Volume resistivity The volume resistivity is measured with a Lorestar resistivity meter (Mitsubishi Chemical, MCP-T610) and a Hiresta resistivity meter (Mitsubishi Chemical, MCP-HT450), and the volume resistivity at a load of 20 kN. asked for Measurement conditions are shown below.
Lorestar resistivity meter measurement method: auto range method, applied voltage 10 V, load 20 kN, sample weight 1.5 g
Hiresta resistivity meter measurement method: auto range method, applied voltage 10 V, load 20 kN, sample weight 1.5 g

（３）初期容量
実施例４、比較例６の正極用化合物粉末を用いてラミネートセル型電池を作製し、すべて２５℃の環境温度で充放電を行った。０．０５Ｃの条件で４．２ＶまでＣＶ条件で充電した後、０．１Ｃの条件で２．７Ｖまで放電した。０．１Ｃの条件で４．２ＶまでＣＶ条件で充電した後、０．２Ｃの条件で２．７Ｖまで放電し、この条件を３サイクル行った。０．２Ｃの条件で４．２ＶまでＣＶ条件で充電した後、０．２Ｃの条件で２．７Ｖまで放電し、この条件を５サイクル行った。０．２Ｃの条件で４．２ＶまでＣＶ条件で充電した後、０．２Ｃの条件で３．０Ｖまで放電し、この条件を３サイクル行った。このときの最終の放電容量を初期容量とした。
（４）２５℃でのＤＣＩＲ測定
実施例４、比較例６の正極用化合物粉末を用いて作製したラミネートセル型電池を用いて、２５℃の環境温度でＳＯＣ５０％における電池のＤＣＩＲ測定を実施した。
（５）負荷特性
実施例４、比較例６の正極用化合物粉末を用いて作製したラミネートセル型電池を用いて、２５℃の環境温度で０．２Ｃの条件で４．２ＶまでＣＶ条件で充電した後、０．２Ｃの条件で３．０Ｖまで放電した。また、２５℃で０．２Ｃの条件で４．２ＶまでＣＶ条件で充電した後、１０Ｃの条件で３．０Ｖまで放電した。０．２Ｃで放電した容量に対する１０Ｃで放電した容量の割合を負荷特性における容量維持率とした。次式に示す。
容量維持率（％）＝１０Ｃ放電容量（mAh/g）／０．２Ｃ放電容量（mAh/g）×１００
（６）ニッケル元素を含む被覆層の平均一次粒子径
実施例３の正極用化合物粉末のニッケル元素を含む被覆層の平均一次粒子径は、電界放出形走査電子顕微鏡（ＦＥ－ＳＥＭ）にて被覆層を観察した画像から、独立して存在している一次粒子をランダムに１０個選択し、選択した上記一次粒子の最長直径の部位を、それぞれ測定し、その平均値を平均一次粒子径とした。(3) Initial Capacity Laminated cell type batteries were produced using the positive electrode compound powders of Example 4 and Comparative Example 6, and charged and discharged at an ambient temperature of 25°C. After charging under 0.05C conditions to 4.2V under CV conditions, it was discharged to 2.7V under 0.1C conditions. After charging to 4.2 V under the condition of 0.1 C under the CV condition, the battery was discharged to 2.7 V under the condition of 0.2 C, and this condition was repeated for 3 cycles. After charging to 4.2 V under the condition of 0.2 C under the CV condition, the battery was discharged to 2.7 V under the condition of 0.2 C, and this condition was repeated for 5 cycles. After charging to 4.2 V under the condition of 0.2 C under the CV condition, discharging to 3.0 V under the condition of 0.2 C, this condition was repeated for 3 cycles. The final discharge capacity at this time was taken as the initial capacity.
(4) DCIR measurement at 25°C Using the laminate cell type batteries produced using the positive electrode compound powders of Example 4 and Comparative Example 6, the DCIR measurement of the battery was performed at an ambient temperature of 25°C and an SOC of 50%. .
(5) Load characteristics Using the laminate cell type batteries produced using the positive electrode compound powders of Example 4 and Comparative Example 6, charge under CV conditions up to 4.2 V under conditions of 0.2 C at an ambient temperature of 25 ° C. After that, the battery was discharged to 3.0V under the condition of 0.2C. Moreover, after charging to 4.2 V under the condition of 0.2 C at 25° C. under the CV condition, the battery was discharged to 3.0 V under the condition of 10 C. The ratio of the capacity discharged at 10C to the capacity discharged at 0.2C was taken as the capacity retention rate in the load characteristics. It is shown in the following formula.
Capacity retention rate (%) = 10C discharge capacity (mAh/g) / 0.2C discharge capacity (mAh/g) x 100
(6) Average primary particle size of coating layer containing nickel element The average primary particle size of the coating layer containing nickel element of the positive electrode compound powder of Example 3 was measured using a field emission scanning electron microscope (FE-SEM). From the image obtained by observing the layer, 10 independently existing primary particles were randomly selected, and the longest diameter portions of the selected primary particles were measured, and the average value was taken as the average primary particle diameter. .

評価結果を下記表３に示す。 The evaluation results are shown in Table 3 below.

Figure 0007290625000003
Figure 0007290625000003

実施例４のリチウム－ニッケル含有被覆ニッケルコバルトマンガン複合酸化物粉末の組成分析を行ったところ、Ｌｉ：Ｎｉ：Ｃｏ：Ｍｎのモル比は、１．０１１：０．５７５：０．１７０：０．２５５であった。比較例６のリチウム－ニッケルコバルトマンガン複合酸化物末の組成分析を行ったところ、Ｌｉ：Ｎｉ：Ｃｏ：Ｍｎのモル比は、１．０２２：０．４９９：０．２００：０．３０１であった。
上記表３に示すように、実施例３のニッケル含有被覆ニッケル複合水酸化物の体積抵抗率４．７１３x１０７Ω・ｃｍは、比較例７の体積抵抗率が１．５５９x１０８Ω・ｃｍであるニッケル複合水酸化物に比べて導電性が向上した。また、実施例４のリチウム－ニッケル含有被覆ニッケル複合酸化物の体積抵抗率１．６７９x１０２Ω・ｃｍは、比較例６の体積抵抗率が５．６０５x１０2Ω・ｃｍであるリチウム－ニッケル複合酸化物に比べて導電性が向上した。When the lithium-nickel-containing coated nickel-cobalt-manganese composite oxide powder of Example 4 was analyzed for composition, the molar ratio of Li:Ni:Co:Mn was 1.011:0.575:0.170:0. was 255. Composition analysis of the lithium-nickel-cobalt-manganese composite oxide powder of Comparative Example 6 revealed that the molar ratio of Li:Ni:Co:Mn was 1.022:0.499:0.200:0.301. rice field.
As shown in Table 3 above, the nickel-containing coated nickel composite hydroxide of Example 3 has a volume resistivity of 4.713×10 7 Ω·cm, while the volume resistivity of Comparative Example 7 is 1.559×10 8 Ω·cm. Conductivity was improved compared to nickel composite hydroxide. Moreover, the volume resistivity of 1.679× 10 2 Ω·cm of the lithium-nickel-containing coated nickel composite oxide of Example 4 is comparable to that of the lithium-nickel composite oxide of Comparative Example 6, which has a volume resistivity of 5.605×10 2 Ω·cm. Conductivity improved compared to other materials.

上記表３に示すように、体積抵抗率が低い実施例４のリチウム－ニッケル含有被覆ニッケル複合酸化物の初期容量１５７．４ｍＡｈ／ｇは、比較例６の初期容量が１５３．９ｍＡｈ／ｇであるリチウム－ニッケル複合酸化物に比べて高い容量を有していた。
上記表３に示すように、体積抵抗率が低い実施例４のリチウム－ニッケル含有被覆ニッケル複合酸化物のＳＯＣ５０％における２５℃でのＤＣＩＲ１．７３Ωは、比較例６のＳＯＣ５０％における２５℃でのＤＣＩＲが１．９８Ωであるリチウム－ニッケル複合酸化物に比べて低い抵抗を有していた。
上記表３に示すように、体積抵抗率が低い実施例４のリチウム－ニッケル含有被覆ニッケル複合酸化物の０．２Ｃで放電した容量に対する１０Ｃで放電した容量の割合を算出した容量維持率６５．６％は、比較例６の０．２Ｃで放電した容量に対する１０Ｃで放電した容量の割合を算出した容量維持率が６５．１％であるリチウム－ニッケル複合酸化物に比べて高い負荷特性を有していた。As shown in Table 3 above, the lithium-nickel-containing coated nickel composite oxide of Example 4 having a low volume resistivity has an initial capacity of 157.4 mAh/g, while the initial capacity of Comparative Example 6 is 153.9 mAh/g. It had a higher capacity than the lithium-nickel composite oxide.
As shown in Table 3 above, the lithium-nickel-containing coated nickel composite oxide of Example 4 having a low volume resistivity has a DCIR of 1.73 Ω at 25 ° C. It had a lower resistance than the lithium-nickel composite oxide with a DCIR of 1.98Ω.
As shown in Table 3 above, the lithium-nickel-containing coated nickel composite oxide of Example 4 having a low volume resistivity was calculated as the ratio of the capacity discharged at 10C to the capacity discharged at 0.2C. 6% has a capacity retention rate of 65.1% calculated as the ratio of the capacity discharged at 10 C to the capacity discharged at 0.2 C in Comparative Example 6. It has higher load characteristics than the lithium-nickel composite oxide. Was.

さらに、実施例３のニッケル元素を含む被覆層の平均一次粒子径が５０ｎｍ～９０ｎｍ微細化されていた。 Furthermore, the average primary particle size of the coating layer containing nickel element in Example 3 was reduced by 50 nm to 90 nm.

本発明の正極用化合物は、上記被覆層の構造を有することにより、初期特性の利用率及び高温放置後における利用率に優れ、高導電性を有するので、広汎な蓄電池の分野で利用可能であり、例えば、アルカリ蓄電池の正極活物質用、非水系電解質二次電池の正極活物質用、非水系電解質二次電池の正極活物質の前駆体用として利用価値が高い。 Since the positive electrode compound of the present invention has the structure of the coating layer, it is excellent in the utilization rate of the initial characteristics and the utilization rate after being left at high temperature, and has high conductivity, so that it can be used in a wide range of storage battery fields. For example, it is highly useful as a positive electrode active material for alkaline storage batteries, a positive electrode active material for non-aqueous electrolyte secondary batteries, and a precursor of a positive electrode active material for non-aqueous electrolyte secondary batteries.

Claims (10)

一次粒子が凝集した二次粒子であり、ニッケル複合水酸化物を含む核と、前記核の表面にコバルト元素が５００ｐｐｍ以下及びリン元素が１０ｐｐｍ以下であるニッケル元素を含む被覆層と、を有する正極用化合物であり、
前記被覆層のニッケル元素の含有量が、前記核１００質量部に対して６質量部以上２０質量部以下、
前記ニッケル元素を含む被覆層の平均一次粒子径が、１０ｎｍ以上９０ｎｍ以下、
体積抵抗率が１．５×１０Ω・ｃｍ以下であり、アルカリ蓄電池の正極活物質用である正極用化合物。 A positive electrode having a core that is a secondary particle obtained by agglomeration of primary particles and contains a nickel composite hydroxide, and a coating layer containing a nickel element having a cobalt element of 500 ppm or less and a phosphorus element of 10 ppm or less on the surface of the core. is a compound for
The content of the nickel element in the coating layer is 6 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the core,
The average primary particle size of the coating layer containing the nickel element is 10 nm or more and 90 nm or less,
A positive electrode compound having a volume resistivity of 1.5×10 Ω·cm or less and used as a positive electrode active material for an alkaline storage battery. 一次粒子が凝集した二次粒子であり、ニッケル複合酸化物を含む核と、前記核の表面にコバルト元素が５００ｐｐｍ以下及びリン元素が１０ｐｐｍ以下であるニッケル元素を含む被覆層と、を有する正極用化合物であり、
前記被覆層のニッケル元素の含有量が、前記核１００質量部に対して６質量部以上２０質量部以下、
体積抵抗率が５．０×１０2Ω・ｃｍ以下であり、非水系電解質二次電池の正極活物質用である正極用化合物。 A positive electrode having a core which is a secondary particle obtained by agglomeration of primary particles and which contains a nickel composite oxide , and a coating layer containing a nickel element having a cobalt element of 500 ppm or less and a phosphorus element of 10 ppm or less on the surface of the core. is a compound for
The content of the nickel element in the coating layer is 6 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the core,
A positive electrode compound having a volume resistivity of 5.0×10 2 Ω·cm or less, which is used as a positive electrode active material for a non-aqueous electrolyte secondary battery. 一次粒子が凝集した二次粒子であり、ニッケル複合水酸化物を含む核と、前記核の表面にコバルト元素が５００ｐｐｍ以下及びリン元素が１０ｐｐｍ以下であるニッケル元素を含む被覆層と、を有する正極用化合物であり、
前記被覆層のニッケル元素の含有量が、前記核１００質量部に対して６質量部以上２０質量部以下、
体積抵抗率が１．５×１０８Ω・ｃｍ以下であり、非水系電解質二次電池の正極活物質の前駆体用である正極用化合物。 A positive electrode having a core that is a secondary particle obtained by agglomeration of primary particles and contains a nickel composite hydroxide, and a coating layer containing a nickel element having a cobalt element of 500 ppm or less and a phosphorus element of 10 ppm or less on the surface of the core. is a compound for
The content of the nickel element in the coating layer is 6 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the core,
A positive electrode compound which has a volume resistivity of 1.5×10 8 Ω·cm or less and which is used as a precursor of a positive electrode active material for a non-aqueous electrolyte secondary battery. 前記核が、コバルト、亜鉛、マンガン、リチウム、マグネシウム、アルミニウム、ジルコニウム、イットリウム、イッテルビウム及びタングステンからなる群から選択された金属元素を少なくとも１種含む請求項１乃至３のいずれかに記載の正極用化合物。 The positive electrode according to any one of claims 1 to 3, wherein the core contains at least one metal element selected from the group consisting of cobalt, zinc, manganese, lithium, magnesium, aluminum, zirconium, yttrium, ytterbium and tungsten. Compound. 前記ニッケル元素を含む被覆層の平均一次粒子径が、１０ｎｍ以上１００ｎｍ以下である請求項２または３に記載の正極用化合物。 4. The positive electrode compound according to claim 2, wherein the coating layer containing nickel element has an average primary particle size of 10 nm or more and 100 nm or less. さらに、パラジウム化合物を含む請求項１乃至５のいずれかに記載の正極用化合物。 6. The positive electrode compound according to any one of claims 1 to 5, further comprising a palladium compound. 前記核が、一般式（１）
Ｎｉ（１－ｘ）Ｍｘ（ＯＨ）２＋ａ （１）
（式中：０＜ｘ≦０．２、０≦ａ≦０．２、Ｍは、コバルト、亜鉛、マンガン、マグネシウム、アルミニウム、イットリウム及びイッテルビウムからなる群から選択された少なくとも１種の金属元素を示す。）で表される請求項１に記載の正極用化合物。 The nucleus has the general formula (1)
Ni (1−x) M x (OH) 2+a (1)
(In the formula: 0 < x ≤ 0.2, 0 ≤ a ≤ 0.2, M is at least one metal element selected from the group consisting of cobalt, zinc, manganese, magnesium, aluminum, yttrium and ytterbium The compound for a positive electrode according to claim 1, which is represented by. 前記核が、一般式（３）
Ｎｉ（１－ｚ）Ｐｚ（ＯＨ）２＋ｃ （３）
（式中：０＜ｚ≦０．７、０≦ｃ≦０．２８、Ｐは、コバルト、亜鉛、マンガン、マグネシウム、アルミニウム、ジルコニウム、イットリウム、イッテルビウム及びタングステンからなる群から選択された少なくとも１種の金属元素を示す。）で表される請求項３に記載の正極用化合物。 The nucleus has the general formula (3)
Ni (1−z) P z (OH) 2+c (3)
(In the formula: 0 < z ≤ 0.7, 0 ≤ c ≤ 0.28, P is at least one selected from the group consisting of cobalt, zinc, manganese, magnesium, aluminum, zirconium, yttrium, ytterbium and tungsten The compound for a positive electrode according to claim 3, which is represented by the following metal element. 請求項８に記載の正極用化合物を前駆体として用いた、非水系電解質二次電池用正極活物質の製造方法。 A method for producing a positive electrode active material for a non-aqueous electrolyte secondary battery, using the positive electrode compound according to claim 8 as a precursor. 前記核が、一般式（２）
Ｌｉ［Ｌｉｙ（Ｎｉ（１－ｂ）Ｎｂ）１－ｙ］Ｏ２ （２）
（式中：０＜ｂ≦０．７、０≦ｙ≦０．５０、Ｎは、コバルト、マンガン、マグネシウム、アルミニウム、ジルコニウム、イットリウム、イッテルビウム及びタングステンからなる群から選択された少なくとも１種の金属元素を示す。）で表される請求項２に記載の正極用化合物。 The nucleus has the general formula (2)
Li[Li y (Ni (1-b) N b ) 1-y ]O 2 (2)
(In the formula: 0 < b ≤ 0.7, 0 ≤ y ≤ 0.50, N is at least one metal selected from the group consisting of cobalt, manganese, magnesium, aluminum, zirconium, yttrium, ytterbium and tungsten The compound for a positive electrode according to claim 2, which is represented by ).
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JP2000294236A (en) 1999-04-07 2000-10-20 Kiyokawa Mekki Kogyo Kk Nickel electrode and its manufacture
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