JP2015187051A - Nickel hydroxide and alkali battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide nickel hydroxide containing α-nickel hydroxide, and capable of attaining initial activation quickly.SOLUTION: In the case where nickel hydroxide contains α-nickel hydroxide and β-nickel hydroxide, and a half band width (2θ) of (003) plane diffraction peak in X-ray diffraction using CuKα-rays is 1° or higher, when the nickel hydroxide is used as a cathode active material of an alkali battery, an initial discharge capacity after battery assembly is large, and quick initial activation becomes possible.

Description

  The present invention relates to nickel hydroxide and alkaline storage batteries.

  Conventionally, alkaline storage batteries such as nickel metal hydride batteries and nickel cadmium batteries have been widely used as power sources for electric devices such as mobile computers, digital cameras, hybrid electric vehicles, electric tools, and toys. In recent years, electric devices have become more sophisticated and multifunctional, and accordingly, alkaline storage batteries are also required to have improved performance.

Conventionally, nickel hydroxide has been widely used as a positive electrode active material for alkaline storage batteries. Nickel hydroxide is mainly known for α-form and β-form crystals. Since β-form has a shorter interlayer distance than alpha-form and can exist stably in an alkaline environment, it can be used as a positive electrode active material for alkaline storage batteries. Widely used. When β-type nickel hydroxide is used as the positive electrode active material, β-type nickel hydroxide is oxidized to β-type nickel oxyhydroxide in charging, and β-type nickel oxyhydroxide is reduced in discharging to form β-type hydroxide. Become nickel. The oxidation-reduction reaction during charging and discharging proceeds with a one-electron reaction (theoretical capacity 289 mAh / g). However, part of β-type nickel oxyhydroxide may be oxidized to γ-type nickel oxyhydroxide, which is a higher-order oxide, due to overcharge. Since γ-type nickel oxyhydroxide does not contribute to the electromotive reaction, it causes a decrease in capacity. In addition, γ-type nickel oxyhydroxide takes in water molecules and metal cations such as K ⁺ and expands between the layers of the crystal lattice, causing volume expansion of the electrode, concentration change of electrolyte, and ubiquity. Yes. As described above, when β-type nickel hydroxide is used as the positive electrode active material, there is a drawback in that battery performance is reduced due to the formation of γ-type nickel oxyhydroxide.

  On the other hand, α-type nickel hydroxide has a small difference in lattice constant from that of γ-type nickel oxyhydroxide and has the same crystal structure. Furthermore, electrons are exchanged between α-type nickel hydroxide and γ-type nickel oxyhydroxide. Since the charge / discharge reaction can be performed reversibly by entering and exiting, a multi-electron reaction can be performed, and the capacity per unit weight of the active material can be increased.

In addition, since α-type nickel hydroxide is used as a positive electrode active material of an alkaline storage battery, various studies have been conducted from the viewpoint of reducing impurities and improving handling properties. For example, in Patent Document 1, as a method for producing an aluminum-substituted α-type nickel hydroxide that hardly contains impurities derived from organic substances, in the presence of an aluminum electrolyte containing metal aluminum and / or aluminum ions (Al ³⁺ ), A method is disclosed in which a substrate is immersed in a reaction solution containing a nickel fluoride complex, and α-type nickel hydroxide is deposited on the surface of the substrate. Further, Patent Document 2 has a crystal structure of α-Ni (OH) ₂ , and the half-value width of the (003) plane diffraction peak obtained by X-ray diffraction measurement using CuKα rays is expressed as a diffraction angle 2θ In the range of 0.5 ° to 3.0 ° and the inter-surface spacing d value within the range of 7.0 to 8.5 mm, and the average particle size and tap density of the secondary particles are within the specific range. It is disclosed that the handleability at the time of electrode manufacture improves melt | dissolution nickel hydroxide particle | grains.

JP 2011-111522 A JP 2001-322817 A

  The present inventor conducted various performance evaluations in order to use α-type nickel hydroxide as a positive electrode active material of an alkaline storage battery. When used as an active material, it has become clear that there is a problem that the time required for the initial activation treatment required for exhibiting prescribed electrical characteristics is long. In order to solve this problem, even if the nickel hydroxide particles contain α form and β form having high conductivity, the problem has not been solved sufficiently.

  Accordingly, the main object of the present invention is to provide nickel hydroxide that contains α-form nickel hydroxide and can be activated quickly.

  The present inventor has intensively studied to solve the above-mentioned problems. As a result, the nickel hydroxide contains α-type nickel hydroxide and β-type nickel hydroxide, and in X-ray diffraction using CuKα rays ( It has been found that when the half-value width (2θ) of the (003) plane diffraction peak is 1 ° or more, rapid initial activation becomes possible when used as a positive electrode active material of an alkaline storage battery. The present invention has been completed by further studies based on such knowledge.

  That is, one embodiment of the present invention contains α-type nickel hydroxide and β-type nickel hydroxide, and the half width (2θ) of the (003) plane diffraction peak in X-ray diffraction using CuKα rays is 1 °. It is nickel hydroxide characterized by the above, and a preferred embodiment thereof is nickel hydroxide in which aluminum is dissolved. When nickel hydroxide satisfies such a configuration, when used as a positive electrode active material of an alkaline storage battery, the initial discharge capacity after battery assembly is large, and rapid initial activation becomes possible.

  Another embodiment of the present invention is selected from the group consisting of a water-soluble salt of nickel and a carboxylic acid, a hydroxy acid, an aminocarboxylic acid, a water-soluble salt thereof, a water-soluble ammonium salt, and a water-soluble chloride salt. The method for producing the nickel hydroxide includes a step of coexisting at least one complexing agent in an aqueous solution. The nickel hydroxide can be efficiently manufactured by a manufacturing method having such a configuration.

  Another embodiment of the present invention includes a step of allowing a water-soluble salt of nickel and an amine compound containing at least one primary or secondary amine to coexist in an aqueous solution having a pH of 9 to 10.5. The method for producing the nickel hydroxide. The nickel hydroxide can also be efficiently manufactured by a manufacturing method having such a configuration.

  When the nickel hydroxide of the present invention is used as a positive electrode active material of an alkaline storage battery, rapid initial activation becomes possible.

For various aluminum solid solution nickel hydroxides having α-type nickel hydroxide and β-type nickel hydroxide, the half width (2θ) of the (003) plane diffraction peak and the ratio of the discharge capacity at the second cycle to the maximum discharge capacity ( It is a figure which shows the result of having analyzed the relationship with%.

1. Nickel hydroxide The nickel hydroxide of the present invention contains α-type nickel hydroxide and β-type nickel hydroxide, and has a half width (2θ) of the (003) plane diffraction peak in X-ray diffraction using CuKα rays. It is characterized by being 1 ° or more. Hereinafter, the nickel hydroxide of the present invention will be described in detail.

[Composition and physical properties]
The nickel hydroxide of the present invention is a mixed crystal state having a crystal structure of α-type nickel hydroxide and a crystal structure of β-type nickel hydroxide. In the nickel hydroxide of the present invention, the ratio of α-type nickel hydroxide and β-type nickel hydroxide is not particularly limited, but from the viewpoint of increasing the capacity of the alkaline storage battery, ) The ratio of the diffraction peak attributed to the plane and the diffraction peak attributed to the (001) plane of β-type nickel hydroxide [(003) / (001)] is usually 0.2 or more, preferably 0.3 to 5, More preferably, 0.33-3 are mentioned. Here, (003) / (001) is a value calculated from the diffraction peak area ratio between the (003) plane and the (001) plane obtained by X-ray diffraction using CuKα rays.

  In the nickel hydroxide of the present invention, the half width (2θ) (FWHM) of the (003) plane diffraction peak of α-type nickel hydroxide in X-ray diffraction using CuKα rays satisfies 1 ° or more. By satisfying such a half width, the initial discharge capacity after battery assembly is improved, and rapid initial activation becomes possible. From the viewpoint of further improving the initial activation rate, the half width of the (003) plane diffraction peak is preferably 1.3 ° or more. Further, the upper limit value of the half-value width of the (003) plane diffraction peak is not particularly limited.

  In order to provide the above-described physical properties, the nickel hydroxide of the present invention preferably contains a metal other than nickel (hereinafter sometimes referred to as “foreign metal”) in a solid solution state. The dissimilar metal to be dissolved in the nickel hydroxide of the present invention is not particularly limited, and examples thereof include rare earth elements including aluminum, cobalt, zinc, magnesium, cadmium, calcium, manganese, and yttrium. Among these dissimilar metals, aluminum is preferably used from the viewpoint of improving the stability of α-form nickel hydroxide in an alkaline environment.

  The content of the dissimilar metal to be dissolved in the nickel hydroxide of the present invention is not particularly limited. For example, the dissimilar metal is 0 to 20 mol%, preferably 5 to 15 mol per total molar amount of the dissimilar metal and nickel. %, More preferably 7 to 12 mol%. By satisfying such dissimilar metal content, it is possible to improve the stability of α-type nickel hydroxide in an alkaline environment.

  The average particle diameter of the nickel hydroxide of the present invention is not particularly limited, but is, for example, 1 to 20 μm, preferably 5 to 15 μm, from the viewpoint that it is easy to apply to the metal substrate of the electrode and hardly causes voids during filling. Can be mentioned. Here, the average particle diameter refers to the median diameter, and is a value calculated by measuring the cumulative distribution of particle diameters using a laser diffraction / scattering particle diameter distribution measuring apparatus (MT3000, manufactured by Mictrotrac).

[Production method]
Although it does not restrict | limit especially about the manufacturing method of the nickel hydroxide of this invention as long as what has the composition and physical property mentioned above can be manufactured, For example, the following 1st method and 2nd method are mentioned.

[First method]
The production method of the first method is at least selected from the group consisting of a water-soluble salt of nickel, a carboxylic acid, a hydroxy acid, an aminocarboxylic acid, a water-soluble salt thereof, a water-soluble ammonium salt, and a water-soluble chloride salt. A step of allowing one complexing agent to coexist in an aqueous solution having a pH of 10.5 to 12.0 (hereinafter also referred to as “reaction solution”).

  Specific examples of the water-soluble salt of nickel include inorganic acid salts such as sulfates; organic acid salts such as nitrates; chloride salts and the like. These nickel water-soluble salts may be used alone or in combination of two or more.

  In the production method of the first method, in order to efficiently produce the nickel hydroxide of the present invention, the reaction solution includes a water-soluble salt of a metal other than nickel (a different metal) and a water-soluble salt of nickel. It is preferable to contain a water-soluble complex. The water-soluble salt of a different metal varies depending on the type of the different metal. For example, in the case of aluminum, an inorganic acid salt such as a sulfate salt; an organic acid salt such as a nitrate salt; . In addition, the water-soluble complex of a different metal varies depending on the type of the different metal. For example, in the case of aluminum, it can be formed by adding a chelating agent such as EDTA to aluminum hydroxide. . The water-soluble salt and / or water-soluble complex of different metals may be used alone or in combination of two or more.

  As the concentration of the water-soluble salt of nickel and the water-soluble salt and / or water-soluble complex of the different metal in the reaction solution, for example, the total amount of nickel ions and different metal ions in the reaction solution is 0.5 to The concentration is 2.5M, preferably 1.0 to 2.0M. What is necessary is just to set so that the ratio of the water-soluble salt of nickel and the water-soluble salt and / or water-soluble complex of a different metal in the said reaction liquid may satisfy the ratio of the nickel mentioned above and a different metal.

  Specific examples of the carboxylic acid used as the complexing agent include monocarboxylic acids such as acetic acid, propionic acid, butyric acid, valeric acid, and caproic acid; and dicarboxylic acids such as oxalic acid and adipic acid. These carboxylic acids may be used alone or in combination of two or more.

  Specific examples of the hydroxy acid used as the complexing agent include lactic acid, malic acid, tartaric acid, and citric acid. These hydroxy acids may be used alone or in combination of two or more.

  Specific examples of the aminocarboxylic acid used as the complexing agent include ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, N-butylethylenediaminetriacetic acid, cyclohexylethylenediaminetoacetic acid, ethylenediaminedipropionic acid, and ethylenediaminetetrapropionic acid. Is mentioned. These aminocarboxylic acids may be used individually by 1 type, and may be used in combination of 2 or more type.

  Specific examples of the water-soluble salts of carboxylic acid, hydroxy acid, and aminocarboxylic acid include alkali metal salts such as sodium salt and potassium salt. These salts may be used individually by 1 type, and may be used in combination of 2 or more type.

  Specific examples of the water-soluble ammonium salt used as the complexing agent include ammonium sulfate, ammonium hydrogen sulfate, and ammonium carbonate. These water-soluble ammonium salts may be used individually by 1 type, and may be used in combination of 2 or more type.

  Specific examples of the water-soluble chloride salt used as the complexing agent include sodium chloride and potassium chloride. These water-soluble chloride salts may be used individually by 1 type, and may be used in combination of 2 or more type.

  In the first method, the complexing agent may be one of carboxylic acid, hydroxy acid, aminocarboxylic acid, water-soluble salt thereof, water-soluble ammonium salt, and water-soluble chloride salt. In addition, two or more kinds may be used in combination. Among these complexing agents, preferably, acetic acid, citric acid, ethylenediaminetetraacetic acid, water-soluble salts thereof, ammonium sulfate, and sodium chloride are used. What is necessary is just to set suitably as the quantity of a complexing agent according to the kind of complexing agent to be used.

  Further, in the reaction solution, the ratio of the complexing agent to the total amount of the water-soluble salt of nickel and the water-soluble salt and / or water-soluble complex of different metals is not particularly limited. For example, it exists in the reaction solution. Examples of the molar ratio of the complexing agent to the total number of moles of nickel ions and different metal ions include 0.01 to 1.0, preferably 0.1 to 0.5.

  About pH of the said reaction liquid, what is necessary is just to adjust suitably, From a viewpoint of manufacturing the nickel hydroxide of this invention more efficiently, Preferably it is 10.5-12.0, More preferably, it is 10.5-11. .5. In order to adjust the pH of the reaction solution to the above range, for example, an alkali agent such as sodium hydroxide or potassium hydroxide may be used.

  In the first method, the preparation procedure of the reaction solution is not particularly limited, but as a preferred embodiment, the water-soluble salt of nickel, the water-soluble salt and / or water-soluble complex of the different metal, and the specific A first aqueous solution in which a complex of nickel and a different metal is formed by mixing the complexing agent is prepared, and the first aqueous solution is mixed with an alkaline agent or an aqueous solution containing the alkaline agent.

  In the preparation of the first aqueous solution, the mixing order of the water-soluble salt of nickel, the water-soluble salt and / or water-soluble complex of the different metal, and the specific complexing agent is not particularly limited. A metal ion aqueous solution containing a water-soluble salt of a different metal and a water-soluble salt and / or a water-soluble complex of a different metal and a complexing agent aqueous solution containing the specific complexing agent are prepared in advance and complexed with the metal ion aqueous solution. It is preferable to prepare by mixing an aqueous agent solution.

  The nickel hydroxide of the present invention is precipitated by incubating the reaction solution. The temperature at which the reaction solution is incubated is not particularly limited, but is 20 to 80 ° C., preferably 30 to 70 ° C., more preferably 40 to 40 ° C. from the viewpoint of efficiently producing the nickel hydroxide of the present invention. 60 degreeC is mentioned.

  Further, the time for incubating the reaction solution may be set as appropriate according to the particle size, particle size distribution, etc. to be provided for the nickel hydroxide to be precipitated. The longer the incubation time, the larger the particle size of the nickel hydroxide to be precipitated. Can be made uniform. The time for incubating the reaction solution is, for example, 10 hours, preferably 20 hours or more, more preferably 50 hours or more.

  Incubating the reaction solution is preferably performed under stirring conditions in order to precipitate nickel hydroxide efficiently.

  Moreover, when incubating the said reaction liquid, you may add an alkaline agent as needed so that a reaction liquid can maintain the said pH range.

  Thus, the nickel hydroxide of the present invention is precipitated by incubating the reaction solution. After the incubation, the precipitate is recovered from the reaction solution by solid-liquid separation treatment such as filtration and centrifugation, washed as necessary, and then subjected to a drying treatment to obtain the nickel hydroxide of the present invention. Moreover, about the temperature conditions in the said drying process, although it does not restrict | limit especially as long as it is a range in which nickel hydroxide is not oxidized, For example, 50-120 degreeC is mentioned.

[Second method]
In the second production method, a nickel water-soluble salt and an amine compound containing at least one primary or secondary amine are expressed as an aqueous solution having a pH of 1 to 9 (hereinafter referred to as “reaction solution”). Including the step of coexisting in

  About the water-soluble salt of nickel used in the second method, the kind, the added amount, and the like are the same as those in the first method.

  In the production method of the second method, in order to efficiently produce the nickel hydroxide of the present invention, a water-soluble salt of a metal other than nickel (foreign metal) and a water-soluble salt of nickel together with the water-soluble salt of nickel and It is preferable to contain a water-soluble complex. About the water-soluble salt and / or water-soluble complex of a different metal used in the second method, the kind, the added amount, and the like are the same as those in the first method.

  The amine compound includes at least one primary or secondary amine and is not particularly limited as long as it can function as a complexing agent. Specifically, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepenta Min etc. are mentioned. These amine compounds may be used individually by 1 type, and may be used in combination of 2 or more type.

  In the reaction solution, the ratio of the amine compound to the total amount of the water-soluble salt of nickel and the water-soluble salt and / or water-soluble complex of a different metal is not particularly limited, but is present in, for example, the reaction solution. The molar ratio of the amine compound to the total number of moles of nickel ions and different metal ions is 0.01 to 1.0, preferably 0.1 to 0.5.

  About pH of the said reaction liquid, what is necessary is just to adjust so that the range of 9-10.5 may be satisfied, but from a viewpoint of manufacturing the nickel hydroxide of this invention more efficiently, as pH of the said reaction liquid, Preferably 10-10.5 is mentioned. In order to adjust the pH of the reaction solution to the above range, the same alkaline agent as in the first method may be used.

  In the second method, the preparation procedure of the reaction solution is not particularly limited, but as a preferred embodiment, the water-soluble salt of nickel, the water-soluble salt and / or water-soluble complex of the different metal, and the amine A predetermined amount of the compound is mixed to prepare a first aqueous solution in which a complex of nickel and a different metal is formed, and the first aqueous solution is mixed with an alkaline agent or an aqueous solution containing an alkaline agent.

  In the preparation of the first aqueous solution, the order of mixing the water-soluble salt of nickel, the water-soluble salt of the dissimilar metal and / or the water-soluble complex, and the specific amine compound is not particularly limited. A metal ion aqueous solution containing a water-soluble salt and a water-soluble salt and / or a water-soluble complex of the different metal and an amine compound aqueous solution containing the specific amine compound are prepared in advance, and the metal ion aqueous solution and the amine compound aqueous solution are prepared. It is preferable to prepare by the method of mixing.

  The nickel hydroxide of the present invention is precipitated by incubating the reaction solution. The temperature, time, operating conditions, etc. when incubating the reaction solution are the same as in the first method. The method for recovering nickel hydroxide precipitated from the reaction solution after the reaction is the same as in the case of the first method.

2. Alkaline storage battery The alkaline storage battery of the present invention comprises the nickel hydroxide. In the alkaline storage battery of the present invention, the nickel hydroxide is used as a positive electrode active material. As described above, in the alkaline storage battery, by using the nickel hydroxide as the positive electrode active material, the initial discharge capacity after the battery assembly is large, and quick initial activation becomes possible.

  In the alkaline storage battery of the present invention, in addition to the positive electrode active material, as a basic configuration of the alkaline storage battery, a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and an electrolytic solution are contained in an outer can. Prepare. Hereinafter, the alkaline storage battery of the present invention will be described in detail.

[Positive electrode]
For the positive electrode, a metal substrate containing nickel hydroxide as a positive electrode active material is used.

  Examples of the metal substrate include perforated plates such as nickel and nickel-plated steel plate perforated plates (punching metal), expanded metals, and foamed metals. Examples of the thickness of the metal substrate include 0.03 to 0.06 mm.

  In addition to the nickel hydroxide, the positive electrode may contain additives such as a conductive agent, a binder, and a thickener as necessary.

  The conductive agent is not particularly limited as long as it is an electron conductive material that does not adversely affect battery performance. Specifically, natural graphite (scale-like graphite, scale-like graphite, earth-like graphite, etc.), artificial graphite, carbon black, acetylene black, ketjen black, carbon whisker, carbon fiber, vapor-grown carbon, metal (Nickel etc.) Powder, metal fiber, etc. are mentioned. These electrically conductive agents may be used individually by 1 type, and may be used in combination of 2 or more type.

  Specific examples of the binder include thermoplastic resins such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride, polyethylene, and polypropylene; ethylene-propylene-diene rubber (EPDM), sulfonated EPDM, and styrene butadiene rubber (SBR). ), And polymers having rubber elasticity such as fluororubber. These binders may be used individually by 1 type, and may be used in combination of 2 or more type.

  Specific examples of the thickener include polysaccharides such as carboxymethylcellulose (CMC) and methylcellulose. These thickeners may be used individually by 1 type, and may be used in combination of 2 or more type.

  The positive electrode is obtained by impregnating or applying a positive electrode active material paste containing the nickel hydroxide and, if necessary, additives such as a conductive agent, a binder, a thickener, and a filler onto a metal substrate, and drying. Can be produced. The addition amount of each component in the positive electrode active material paste is not particularly limited as long as the main component is nickel hydroxide. For example, per 100 parts by mass of the total solid content in the positive electrode active material paste, the nickel hydroxide is 79 to 99 parts by mass, 0 to 20 parts by mass for the conductive agent, and 0.1 to 1 part by mass for the binder.

  Examples of the method of impregnating or applying the positive electrode active material paste onto the metal substrate include roller coating such as applicator roll, screen coating, doctor blade method, spin coating, bar coater and the like.

  After impregnating or applying the positive electrode active material paste to the metal substrate, drying is performed by a hot air drying furnace, an infrared drying furnace, etc., and after drying, pressure forming to a predetermined thickness and cutting to a required dimension can do.

[Negative electrode]
For the negative electrode, a metal substrate containing a negative electrode active material is used.

  Although it does not restrict | limit especially about the said negative electrode active material, For example, hydrogen storage alloy powder, cadmium oxide powder, cadmium hydroxide powder etc. can be used.

  The metal substrate used for the negative electrode is the same as the metal substrate used for the positive electrode.

  In addition to the negative electrode active material, the negative electrode may contain additives such as a conductive agent, a binder, and a thickener as necessary. The types of these additives are the same as those used for the positive electrode.

  The negative electrode is produced by impregnating or coating a metal substrate with a negative electrode active material paste containing the negative electrode, the substance, and, if necessary, additives such as a conductive agent, a binder, and a thickener, and drying. be able to. About the addition amount of each additive in a negative electrode active material paste, the method of impregnating or apply | coating a negative electrode active material paste to a metal substrate, etc. are the same as that of the said positive electrode.

[Separator]
As the separator, a known porous film or nonwoven fabric exhibiting excellent high rate discharge characteristics can be used alone or in combination. Examples of the material constituting the separator include polyolefin resins such as polyethylene and polypropylene, nylon, and the like.

  The porosity of the separator is not specifically limited, but is preferably 80% by volume or less with respect to the volume of the separator from the viewpoint of strength and gas permeability, and preferably 20% by volume or more from the viewpoint of charge / discharge characteristics.

  The separator may be subjected to a hydrophilic treatment. For example, the surface of polyolefin resin fibers such as polyethylene may be subjected to hydrophilic group graft polymerization treatment, sulfonation treatment, corona treatment, PVA treatment, etc., and these hydrophilic treatments may also be used. You may use the sheet | seat which mixed the fiber already given.

[Electrolyte]
As the electrolytic solution, those generally proposed for use in alkaline batteries and the like can be used. Preferable examples of the electrolytic solution include an electrolytic solution in which water is used as a solvent and potassium hydroxide, sodium hydroxide and lithium hydroxide are used alone or a mixture of two or more thereof is dissolved as a solute.

  In addition, additives such as yttrium, ytterbium, erbium, calcium, sulfur, and zinc are added to the electrolyte as necessary for the purpose of anticorrosion, improvement of overvoltage at the positive electrode, improvement of corrosion resistance of the negative electrode, or improvement of self-discharge. May be added. These additives may be used individually by 1 type, and may be used in combination of 2 or more type.

  It is preferable that the electrolytic solution is injected after the electrode group in which the positive electrode, the negative electrode, and the separator are wound is stored in a battery case. As the injection method, it is possible to inject at normal pressure, but a vacuum impregnation method, a pressure impregnation method, and a centrifugal impregnation method can also be used.

[Electrolyte]
The material of the outer can (battery case) is not particularly limited, and examples thereof include iron bases, stainless steel, polyolefin resins, and the like, which are formed with a conductive protective layer as necessary. .

  EXAMPLES Hereinafter, although this invention is demonstrated concretely using an Example, this invention is limited to these Examples and is not interpreted.

1. Preparation of Aluminum Solid Solution Nickel Hydroxide An aqueous solution containing nickel sulfate and aluminum nitrate and an aqueous solution containing a complexing agent containing the complexing agent shown in Table 1 were prepared, and these were mixed to obtain 1. A first aqueous solution containing 35 M, 0.15 M aluminum nitrate and a complexing agent in the proportions shown in Table 1 was prepared. The obtained first aqueous solutions and 6M sodium hydroxide solution were added to the reaction vessel so that the solution (reaction solution) after mixing had the pH shown in Table 1, and stirring was performed at 50 ° C. for 50 hours. The aluminum solid solution nickel hydroxide was deposited. Subsequently, the precipitated aluminum solid solution nickel hydroxide was filtered off using a filter press, washed with water, and then dried under a temperature condition of 80 ° C. to obtain aluminum solid solution nickel hydroxide particles.

2. Composition analysis of aluminum solid solution nickel hydroxide About each aluminum solid solution nickel hydroxide obtained, the half width at 2θ of the diffraction peak of the (003) plane of α-type nickel hydroxide by powder X-ray diffraction (XRD) ( FWHM (003)) was measured (Table 1). Further, the diffraction peak of (001) plane of β-form nickel hydroxide at 2θ = 18-22 ° was also measured. As a result, it was confirmed that each aluminum solid solution nickel hydroxide is a mixed crystal state of α-type nickel hydroxide and β-type nickel hydroxide.

3. Evaluation of battery characteristics <Preparation of nickel electrode>
To the obtained aluminum solid solution nickel hydroxide, 10% by weight of cobalt hydroxide was added as a conductive additive. This was mixed with an aqueous solution of carboxymethyl cellulose (CMC) having a concentration of 1% by mass and PTFE to obtain a nickel electrode paste. The composition of the solid content in the nickel electrode paste is nickel hydroxide: α-Co (OH) ₂ : PTFE + CMC = 89.5: 10: 0.5.

A nickel electrode paste having a thickness of 1.4 mm and a density per area of 320 g / m ² is filled with a nickel electrode paste so as to have an electrode capacity of 250 mAh. A 4 mm nickel plate was used. This original plate was cut into 40 mm × 60 mm to obtain a nickel electrode (positive electrode) of an alkaline storage battery.

<Production of hydrogen storage alloy electrode>
After mixing raw materials with a composition of Mm _1.0 Ni _4.0 Co _0.7 Al _0.3 Mn _0.3 (Mm is Misch metal), an alloy ingot is produced by high frequency induction heating in an inert atmosphere, heat treated at 1000 ° C. for 7 hours, A hydrogen storage alloy powder was prepared by pulverizing to a diameter of 50 μm. This powder was mixed with a dispersion of styrene butadiene rubber (SBR) and an aqueous solution of methyl cellulose (MC) to obtain a hydrogen storage alloy paste. This paste was applied to a base material obtained by applying a 1 μm-thick nickel plating to a 45 μm-thick Fe base material and dried to obtain an original plate. The original plate was cut into a size of 45 mm × 65 mm to produce a hydrogen storage alloy electrode (negative electrode) having an electrode capacity of 500 mAh or more.

<Production of evaluation cell>
A separator made of synthetic resin was placed on both sides of each of the produced nickel electrodes, sandwiched between two hydrogen storage alloy electrodes, and set in a container. An Hg / HgO electrode was provided as a reference electrode. An alkaline electrolyte containing 6.8 mol / L of potassium hydroxide (KOH) was poured to such an extent that the electrode was sufficiently immersed to produce an open type cell. It is presumed that the α-Co (OH) ₂ particles in the nickel electrode are reprecipitated on the surface of the aluminum solid solution nickel hydroxide through dissolution in the electrolytic solution during charging and discharging.

The cell was initially charged for 15 hours with a current of 0.1 ItA (25 mA). Here, “ItA” represents the magnitude of the charge / discharge current of the storage battery, and is obtained by adding the unit of It and current to a multiple of the numerical value representing the rated capacity of the battery. It is presumed that α-Co (OH) ₂ particles were oxidized to Co oxyhydroxide during the initial charge. After initial charging, the battery was stopped for 1 hour and discharged at 0.2 ItA (50 mA) until the positive electrode potential became equal to the reference electrode potential. This cycle charge / discharge was repeated 10 times. The discharge capacity and the maximum discharge capacity at the second cycle were measured.

4). Results The results obtained are shown in Table 1 and FIG. From this result, nickel hydroxide is in a mixed crystal state having α-type nickel hydroxide and β-type nickel hydroxide, and the half-value width (2θ of the (003) plane diffraction peak in X-ray diffraction using CuKα rays. ) Is 1 ° or more, the discharge capacity of the second cycle is high, the ratio of the discharge capacity of the second cycle to the maximum discharge capacity is 80% or more, and it is confirmed that initial activation can be performed quickly. (Examples 1-6). On the other hand, when the half width (2θ) of the (003) plane diffraction peak is less than 1 °, the discharge capacity at the second cycle and the ratio of the discharge capacity at the second cycle to the maximum discharge capacity are both low. (Comparative Examples 1-4).

Claims (6)

  It contains α-form nickel hydroxide and β-form nickel hydroxide, and the half-value width (2θ) of the (003) plane diffraction peak in X-ray diffraction using CuKα rays is 1 ° or more, Nickel hydroxide.   The nickel hydroxide according to claim 1, wherein aluminum is dissolved.   The nickel hydroxide according to claim 1 or 2, wherein a half width (2θ) of a (003) plane diffraction peak in X-ray diffraction using CuKα rays is 2 ° or more and 5 ° or less.   The alkaline storage battery containing the nickel hydroxide in any one of Claims 1-3.   A water-soluble salt of nickel and at least one complexing agent selected from the group consisting of carboxylic acid, hydroxy acid, aminocarboxylic acid, water-soluble salt thereof, water-soluble ammonium salt, and water-soluble chloride salt The method of manufacturing nickel hydroxide of Claim 1 including the process made to coexist in aqueous solution.   The nickel hydroxide according to claim 1, comprising a step of allowing a water-soluble salt of nickel and an amine compound containing at least one primary or secondary amine to coexist in an aqueous solution having a pH of 9 to 10.5. How to manufacture.