JP2002289187A - beta TYPE NICKEL OXYHYDROXIDE, MANUFACTURING METHOD THEREOF, POSITIVE ELECTRODE ACTIVE MATERIAL, POSITIVE ELECTRODE FOR BATTERY, AND NICKEL ZINC BATTERY - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nickel zinc battery capable of improving preservation characteristics of the battery. SOLUTION: A nickel zinc battery 1 comprises a positive electrode 3 in which a mixed powder containing at least β type nickel oxyhydroxide which is a positive electrode active material and graphite powder which is a conductive agent is pellet-molded into a hollowcylinder shape. Further, a negative electrode 5 containing at least a zinc which is a negative electrode active material, electrolyte, and gelling agent is disposed at a central part. The positive electrode 3 comprises an alkali earth metal compound. The alkali earth metal compound comprises hydroxide, oxide, and the like of alkali earth metal. The alkali earth metal comprises Ca, Mg, Sr, Ba and the like. The positive electrode 3 comprises rare earth compound. The rare earth compound comprises hydroxide, oxide, and the like of the rare earth element. The rare earth element comprises Y, Yb, Er, Gd and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a beta-type nickel oxyhydroxide and a method for producing the same, a positive electrode active material using the beta-type nickel oxyhydroxide, a positive electrode for a battery containing the positive electrode active material, and a nickel-zinc battery. About.

[0002]

2. Description of the Related Art In recent years, the spread of small portable electronic devices, especially portable game machines and digital cameras, has been extremely remarkable. Are also expected to expand rapidly. Since such electronic devices generally have a high operating voltage and require a large current, their power sources must have excellent discharge characteristics under heavy loads.

The most widespread battery satisfying this requirement is an alkaline manganese battery using manganese dioxide as a positive electrode and zinc as a negative electrode, and using a high-concentration alkaline aqueous solution as an electrolyte. Since this battery is inexpensive for both manganese dioxide and zinc, and has a high energy density per unit weight, it is widely used, including power supplies for small portable electronic devices.

[0004] In view of the use in such small portable devices, the alkaline manganese battery has been subjected to a number of improvements from the battery material to the battery configuration in order to further improve the heavy load discharge characteristics. Have been. However, in this battery system, since the discharge of manganese dioxide, which is the positive electrode active material, is a uniform solid phase reaction, the voltage gradually decreases due to the discharge, and the discharge curve draws rightward. However, in small portable electronic devices that require large currents, the discharge behavior of such alkaline manganese batteries is basically only marginally tolerable, and the usable time of the devices is still small even after various improvements have been made. There are only a few. In addition, small portable electronic devices tend to operate at relatively high voltage and high current in the early stages of their introduction to the market, and batteries with superior heavy load characteristics that can support such new devices in the future. Is essential.

As a battery satisfying such requirements, a nickel zinc battery has been conventionally proposed. This battery is
This is a battery using nickel oxyhydroxide for the positive electrode and zinc for the negative electrode. The battery has a higher operating voltage than the alkaline manganese battery and is excellent in heavy load characteristics.

The nickel oxyhydroxide includes a high-density beta-nickel oxyhydroxide (β-NiOOH, true density: 4.68 g / cm ³ ) and a low-density gamma nickel oxyhydroxide (γ-NiOOH). NiOOH, true density: 3.79
g / cm ³ ). As a method using nickel oxyhydroxide for a nickel zinc battery, a method using a gamma-type nickel oxyhydroxide having little storage deterioration, such as Japanese Patent Laid-Open No. 10-214621, has been proposed. .

[0007] However, as described above, gamma-type nickel oxyhydroxide has a lower density than beta-type nickel oxyhydroxide, and a battery constituted by using the same has a higher operating potential than an alkaline manganese battery. However, there is a disadvantage that the discharge capacity is reduced.

On the other hand, since beta-type nickel oxyhydroxide has a higher density than gamma-type nickel oxyhydroxide, a battery formed using the same can obtain a large discharge capacity. However, batteries using beta-type nickel oxyhydroxide have a problem that storage deterioration is more remarkable than batteries using gamma-type nickel oxyhydroxide.

On the other hand, with the spread of portable electronic equipment in recent years, the demand for cylindrical alkaline batteries is increasing. In addition, since a portable electronic device which has conventionally had a high driving voltage is gradually reduced in voltage, a secondary battery of a low voltage system occupies a very important position. On the other hand, by changing a primary battery into a secondary battery and repeatedly using it, the environmental load can be reduced.

Conventionally, there are a nickel hydride battery and a nickel cadmium battery as batteries using nickel as a positive electrode active material. In both cases, a nickel positive electrode is mainly used as nickel hydroxide. First of all, there is a drawback that it is necessary to charge the battery and it cannot be used immediately at the time of production.

On the other hand, an alkaline battery using manganese dioxide as a positive electrode active material and zinc as a negative electrode active material has been proposed as a battery which does not require initial charging. However, manganese dioxide has poor reversibility in the charge / discharge cycle, and it is difficult to return to the initial manganese dioxide even if charged after being discharged. Therefore, the capacity rapidly deteriorates when charge / discharge cycles are repeated.

[0012] Such capacity degradation due to charge / discharge cycles also occurs in nickel zinc batteries using beta-type nickel oxyhydroxide as the active material for the positive electrode active material. The capacity deterioration is caused by an increase in internal resistance due to electrode expansion due to generation of gamma-type nickel oxyhydroxide during charging. Attempts have been made to prevent capacity degradation due to charge / discharge cycles by suppressing electrode expansion, but it is difficult to solve the problem.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and a battery positive electrode capable of improving the storage characteristics of a battery, and a nickel zinc battery using the battery positive electrode. The purpose is to provide.

Further, the present invention provides a beta-type nickel oxyhydroxide capable of suppressing capacity deterioration due to a charge / discharge cycle, a method for producing the same, a positive electrode active material using the beta-type nickel oxyhydroxide, and a positive electrode active material. An object is to provide a nickel zinc battery to be used.

[0015]

The positive electrode for a battery according to the present invention comprises:
It contains beta-type nickel oxyhydroxide and an alkaline earth metal compound. As the above-mentioned alkaline earth metal compound, one or more compounds selected from hydroxides or oxides of alkaline earth metals may be added. Further, the above-mentioned alkaline earth metal is Ca, Mg, S
It may be composed of one or more metals selected from r and Ba. Further, the above-mentioned alkaline earth metal may be in the range of 0.08 to 3.0% by mass based on the beta-type nickel oxyhydroxide. The above-mentioned beta-type nickel oxyhydroxide may have a substantially spherical particle shape.
The above-mentioned beta type nickel oxyhydroxide may have a tap density of 2.2 to 2.7 g / cm ³ and a bulk density of 1.6 to 2.2 g / cm ³ .

The battery positive electrode of the present invention contains beta-type nickel oxyhydroxide and a rare earth element compound. In some cases, one or more compounds selected from hydroxides or oxides of rare earth elements are added as the rare earth element compounds. Further, when the rare earth element is Y, Y
It may be composed of one or more elements selected from b, Er, and Gd. The rare earth element may be in the range of 0.08 to 3.1% by mass with respect to the beta-type nickel oxyhydroxide. The above-mentioned beta-type nickel oxyhydroxide may have a substantially spherical particle shape.
The above-mentioned beta type nickel oxyhydroxide may have a tap density of 2.2 to 2.7 g / cm ³ and a bulk density of 1.6 to 2.2 g / cm ³ .

The nickel-zinc battery of the present invention comprises a positive electrode obtained by forming a mixed powder containing at least a beta-type nickel oxyhydroxide serving as a positive electrode active material and graphite powder into a hollow cylindrical shape, and disposing the positive electrode on the outer periphery. In a nickel zinc battery, a negative electrode containing zinc and an electrolytic solution is disposed in the center, and a separator is disposed between the positive electrode and the negative electrode. In a nickel zinc battery, beta-type nickel oxyhydroxide containing an alkaline earth metal compound in particles is included. It is.

In some cases, one or more compounds selected from hydroxides or oxides of alkaline earth metals are added as the above alkaline earth metal compound. Further, the above-mentioned alkaline earth metal is Ca, Mg, Sr, B
It may consist of one or more metals selected from a.
Further, the above-mentioned alkaline earth metal may be in the range of 0.08 to 3.0% by mass based on the beta-type nickel oxyhydroxide. The above-mentioned beta-type nickel oxyhydroxide may have a substantially spherical particle shape. Also,
The above-mentioned beta-type nickel oxyhydroxide has a tap density of 2.2 to 2.7 g / cm ³ and a bulk density of 1.6.
To 2.2 g / cm ³ in some cases.

The nickel-zinc battery of the present invention comprises a positive electrode obtained by forming a mixed powder containing at least a beta-type nickel oxyhydroxide as a positive electrode active material and graphite powder into a hollow cylindrical shape, and disposing the positive electrode on the outer peripheral portion. In the nickel zinc battery, a beta-type nickel oxyhydroxide in which a rare earth element compound is contained in particles is disposed in the center of a negative electrode containing zinc and an electrolytic solution, and a separator is disposed between the positive electrode and the negative electrode. .

In some cases, one or more compounds selected from hydroxides or oxides of rare earth elements are added as the rare earth element compound. Further, the rare earth element described above may be composed of one or more elements selected from Y, Yb, Er, and Gd. In addition, the rare earth element described above is 0.08 to
It may be in the range of 3.1% by mass. The above-mentioned beta-type nickel oxyhydroxide may have a substantially spherical particle shape. The above-mentioned beta type nickel oxyhydroxide may have a tap density of 2.2 to 2.7 g / cm ³ and a bulk density of 1.6 to 2.2 g / cm ³ .

The beta-type nickel oxyhydroxide of the present invention contains at least one of magnesium, calcium, strontium and barium. The above-mentioned beta type nickel oxyhydroxide may be as follows. That is, beta-type nickel oxyhydroxide is one of magnesium, calcium, strontium, and barium.
More than one kind of elements are contained in a total amount of 0.01 to 30% by mass. The above-mentioned beta type nickel oxyhydroxide may be as follows. That is, the beta-type nickel oxyhydroxide has a substantially spherical particle shape. The above-mentioned beta type nickel oxyhydroxide may be as follows. That is, the beta-type nickel oxyhydroxide has a tap density of 1.8 to 2.7 (g / cm ³ ) and a bulk density of 1.4 to 2.2 (g / cm ³ ).

The present invention is a method for producing beta-type nickel oxyhydroxide including the following steps. That is, (a)
Contains one or more elements of magnesium, calcium, strontium and barium by adding an alkaline aqueous solution to a nickel salt aqueous solution containing one or more metal salts of magnesium salt, calcium salt, strontium salt and barium salt First step of synthesizing nickel hydroxide. (B) A second step of oxidizing the nickel hydroxide in an alkaline liquid phase containing hypochlorite to synthesize beta-type nickel oxyhydroxide.

The method for producing the above-mentioned beta-type nickel oxyhydroxide may be as follows. That is, nickel hydroxide has a substantially spherical particle shape. Further, the above-mentioned method for producing the beta-type nickel oxyhydroxide may be as follows. That is, the beta-type nickel oxyhydroxide has a substantially spherical particle shape. Further, the above-mentioned method for producing the beta-type nickel oxyhydroxide may be as follows. That is, beta-type nickel oxyhydroxide is magnesium,
Contains at least one element of calcium, strontium, and barium in a total amount of 0.01 to 30% by mass.

The positive electrode active material of the present invention is as follows in a positive electrode active material comprising beta-type nickel oxyhydroxide. That is, beta-type nickel oxyhydroxide is
Contains one or more elements of magnesium, calcium, strontium, barium.

The above-mentioned positive electrode active material may be as follows.
That is, beta-type nickel oxyhydroxide contains at least one element of magnesium, calcium, strontium, and barium in a total amount of 0.01 to 30% by mass. The above-mentioned positive electrode active material may be as follows. That is, the beta-type nickel oxyhydroxide has a substantially spherical particle shape. The above-mentioned positive electrode active material may be as follows. That is, the beta-type nickel oxyhydroxide has a tap density of 1.8 to 2.7 (g / cm ³ ) and a bulk density of 1.4 to 2.2 (g / cm ³ ).

The nickel-zinc battery of the present invention is characterized in that a mixed powder containing at least beta-type nickel oxyhydroxide, which is a positive electrode active material, and graphite powder is formed into a hollow cylindrical pellet, and the positive electrode is disposed on the outer periphery. In a nickel zinc battery in which a negative electrode containing zinc and an electrolytic solution is disposed at the center and a separator is disposed between the positive electrode and the negative electrode, the following is obtained. That is, beta-type nickel oxyhydroxide contains at least one element of magnesium, calcium, strontium, and barium.

The above-mentioned nickel zinc battery has the following cases. That is, beta-type nickel oxyhydroxide contains at least one element of magnesium, calcium, strontium, and barium in a total amount of 0.01 to 30% by mass.
contains. Further, the above-mentioned nickel zinc battery may have the following cases. That is, the beta-type nickel oxyhydroxide has a substantially spherical particle shape. Further, the above-mentioned nickel zinc battery may have the following cases. That is, the beta-type nickel oxyhydroxide has a tap density of 1.8 to 2.7.
(G / cm ³ ) and the bulk density is 1.4 to 2.2.
(G / cm ³ ).

According to the battery positive electrode and the nickel zinc battery of the present invention, the battery positive electrode contains beta-type nickel oxyhydroxide and an alkaline earth metal compound, or the battery positive electrode has beta-type nickel oxyhydroxide and a rare earth element. A negative electrode containing at least an elemental compound, or a positive electrode obtained by pelletizing a mixed powder containing at least a positive electrode active material and graphite powder into a hollow cylindrical shape is disposed on an outer peripheral portion, and a negative electrode containing at least zinc as a negative electrode active material and an electrolyte solution In a nickel zinc battery, wherein the positive electrode comprises beta-type nickel oxyhydroxide and an alkaline earth metal compound, or the positive electrode comprises beta-type nickel oxyhydroxide. And rare earth compounds,
The reaction between beta-type nickel oxyhydroxide and potassium hydroxide is suppressed, and self-discharge of the battery is reduced.

According to the beta-type nickel oxyhydroxide and the method for producing the same, the positive electrode active material, and the nickel-zinc battery of the present invention, the beta-type oxyhydroxide containing at least one element of magnesium, calcium, strontium, and barium is used. By using nickel hydroxide, or
By providing a method for producing beta-type nickel oxyhydroxide including the following steps, namely, adding an aqueous alkali solution to an aqueous nickel salt solution containing one or more of magnesium salts, calcium salts, strontium salts, and barium salts , Magnesium, calcium, strontium,
A first step of synthesizing nickel hydroxide containing one or more elements of barium,
In the second step of oxidizing in an alkaline liquid phase containing hypochlorite to synthesize beta-type nickel oxyhydroxide, or in a positive electrode active material composed of beta-type nickel oxyhydroxide, beta-type nickel oxyhydroxide However, by containing at least one element of magnesium, calcium, strontium, barium, or a mixed powder containing at least beta-type nickel oxyhydroxide and graphite powder as a positive electrode active material into a hollow cylindrical shape In a nickel-zinc battery, a beta-type nickel oxyhydroxide was used in which a pellet-formed positive electrode was disposed on an outer peripheral portion, a negative electrode containing zinc as a negative electrode active material and an electrolytic solution was disposed in a central portion, and a separator was disposed between the positive electrode and the negative electrode. Contains at least one element of magnesium, calcium, strontium and barium, In beta-type nickel oxyhydroxide in which at least one element selected from the group consisting of calcium, strontium, and barium is dissolved, defects are formed in the crystal and distortion of the crystal increases the freedom of protons and increases the diffusion rate. growing.

[0030]

Embodiments of the present invention will be described below. First, a battery positive electrode containing beta-type nickel oxyhydroxide and an alkaline earth metal compound, or a battery positive electrode containing beta-type nickel oxyhydroxide and a rare earth element compound, and a nickel zinc battery using these battery positive electrodes An embodiment of the present invention will be described.

First, the configuration of the battery according to the present embodiment will be described. FIG. 1 is a cross-sectional view showing a nickel zinc battery 1 as one configuration example of the battery according to the present embodiment. That is, the nickel-zinc battery 1 includes a beta-type nickel oxyhydroxide (β-NiOO)
H) and a positive electrode containing an alkaline earth metal compound or a rare earth element compound, and a negative electrode using zinc as a negative electrode active material.

Specifically, this nickel zinc battery 1
A battery can 2, a positive electrode 3, a separator 4, a negative electrode 5, a sealing member 6, a washer 7, a negative electrode terminal plate 8, and a current collecting pin 9 are provided. Here, the battery can 2 is a hollow cylindrical metal can having a bottom and an opening. Battery can 2
For example, iron is nickel-plated and serves as an external positive terminal of the battery.

The positive electrode 3 has a hollow cylindrical shape, and includes nickel oxyhydroxide as a positive electrode active material, an alkaline earth metal compound or a rare earth element compound, graphite powder as a conductive agent, and water as an electrolytic solution. Positive electrode pellets 3a and 3 each formed by molding a positive electrode mixture comprising an aqueous potassium oxide solution into a hollow cylinder
b, 3c are laminated inside the battery can 2. The specific content of the nickel oxyhydroxide contained in the positive electrode 3 will be described later.

The separator 4 has a hollow cylindrical shape with a bottom and is disposed so as to be in contact with the inside of the positive electrode 3. Negative electrode 5
Comprises a zinc powder to be a negative electrode active material, an electrolyte using an aqueous solution of potassium hydroxide, and a gelling agent for uniformly dispersing the zinc powder and the electrolyte by forming the negative electrode 5 in a gel state. The negative electrode 5 is injected into the bottomed cylindrical separator 4.

The opening of the battery can 2 in which the positive electrode 3 and the separator 4 filled with the negative electrode 5 are accommodated,
A sealing member 6 is fitted to seal the opening. The sealing member 6 is made of a plastic material, and a washer 7 and a negative electrode terminal plate 8 are attached so as to cover the sealing member 6.

Further, a current collecting pin 9 made of brass is press-fitted from above into the through hole of the sealing member 6 to which the washer 7 is attached. Thereby, the current collection of the negative electrode is ensured by the nail-shaped current collecting pin 9 welded to the negative electrode terminal plate 8 being pressed into the through hole formed at the center of the sealing member 6 and reaching the negative electrode. I have. The current collection of the positive electrode is ensured by connecting the positive electrode 3 and the battery can 2. The outer peripheral surface of the battery can 2 is covered with an exterior label (not shown), and the positive electrode terminal is located below the battery can 2.

Next, nickel oxyhydroxide, which is a positive electrode active material, will be described in detail. In the present embodiment, nickel oxyhydroxide, particularly beta-type nickel oxyhydroxide is employed as the positive electrode active material.

FIG. 3 shows a substantially spherical beta-type nickel oxyhydroxide (A) used for the positive electrode active material of the battery according to the present embodiment and a non-spherical beta-type oxyhydroxide used for the positive electrode active material of the conventional battery. It is a figure which shows nickel oxide (B). Here, in FIG. 3A and FIG. 3B, the upper row shows electron micrographs of the beta-type nickel oxyhydroxide of the present embodiment and the conventional beta-type nickel oxyhydroxide, respectively. The outline of the particles in the photograph is shown for easy understanding.

As can be seen from FIG. 3A, the beta-type nickel oxyhydroxide according to the present embodiment has a substantially spherical particle shape. That is, the surfaces of the particles are relatively smooth with sharp corners, and the overall shape is slightly elongated and slightly flat, but generally spherical.
In contrast, as can be seen from FIG. 3B, the conventional beta-type nickel oxyhydroxide is non-spherical.

The positive electrode active material used in the present embodiment,
It is desirable that the beta-type nickel oxyhydroxide is in the range of the following average particle size and particle size distribution. That is, the average particle size of the beta-type nickel oxyhydroxide is 19 to 40 μm.
It is desirable to be within the range of m. The particle size distribution of the beta-type nickel oxyhydroxide is preferably in the range of 5 to 80 μm. Note that the minimum value of the particle size distribution is 5% below the sieve, and the maximum value of the particle size distribution is 95% below the sieve.
% Value.

It is desirable that the tap (Tap) density and the bulk (Bulk) density of the substantially spherical beta-type nickel oxyhydroxide are within the following ranges. That is, the tap density of the beta-type nickel oxyhydroxide is 2.2 to 2.7 g /
It is desirably in the range of cm ³ . The bulk density of the beta-type nickel oxyhydroxide is 1.6 to 2.2 g /
It is desirably in the range of cm ³ .

The method for measuring the tap density and the bulk density (also referred to as "bulk density") is as follows. That is, the target powder was naturally dropped and filled in a specific container, the mass at this time was A (g), the volume was B (cm ³ ), the container was lifted, and the bottom of the container was lightly hit on a desk or the like 200 times. When the volume after (tapping) is C (cm ³ ), it is defined by the following equation. Bulk density = A / B (g / cm ³ ) Tap density = A / C (g / cm ³ )

Next, the alkaline earth metal compound added to the positive electrode will be described. The positive electrode according to the present embodiment contains beta-type nickel oxyhydroxide and an alkaline earth metal compound. Here, the alkaline earth metal compound is an alkaline earth metal hydroxide, an alkaline earth metal oxide, or the like. The method of adding the alkaline earth metal hydroxide and the alkaline earth metal oxide may be any one of them, or may be a mixture of any combination thereof. It may be.

The alkaline earth metal compound is not limited to the above alkaline earth metal hydroxide or alkaline earth metal oxide. As the alkaline earth metal compound, an alkaline earth metal salt or the like can be employed.

The alkaline earth metals are Ca, Mg,
Sr, Ba, etc. can be adopted. Here, the method of employing the alkaline earth metal may be any one of these, or may be a mixture of any combination thereof.

The alkaline earth metal in the positive electrode is 0.08 to 0.08 to the positive electrode active material (beta type nickel oxyhydroxide).
It is desirable to be in the range of 3.0% by mass. Further, the alkaline earth metal in the positive electrode is more preferably in the range of 0.1 to 3.0% by mass based on the positive electrode active material (beta-type nickel oxyhydroxide). Here, “mass%” is
The total mass of the alkaline earth metal present in the alkaline earth metal compound is expressed as a percentage with respect to the total mass of the positive electrode active material.

The average particle size of the alkaline earth metal compound is 10
It is desirably within the range of ５０50 μm. When the average particle size is within this range, there is an advantage that the alkaline earth metal compound is easily dispersed in the positive electrode.

The particle size distribution of the alkaline earth metal compound is 1 to
It is desirable to be within the range of 100 μm. If the particle size distribution is within this range, there is an advantage that the alkaline earth metal compound is easily dispersed in the positive electrode.

Next, the rare earth element compound added to the positive electrode active material will be described. The positive electrode according to the present embodiment contains beta-type nickel oxyhydroxide and a rare earth element compound. Here, the rare earth element compound is a hydroxide of a rare earth element, an oxide of a rare earth element, or the like. The method of adding the hydroxide of the rare earth element and the oxide of the rare earth element may be any one of them, or may be a mixture of any combination thereof. You may.

The rare earth element compound is not limited to the above-mentioned hydroxide of the rare earth element or the oxide of the rare earth element. As the rare earth element compound, a salt of the rare earth element or the like can be employed.

The rare earth elements are Y, Yb, Er, G
d or the like can be adopted. Here, the method of adopting the rare earth element may be any one of them, or may be a mixture of any combination of these.

It should be noted that the rare earth elements are represented by Y, Yb, E described above.
It is not limited to r and Gd. As the rare earth element, Sc, La, Ce, Tm or the like can be employed.

The rare earth element in the positive electrode is 0.08 to 3.1 with respect to the positive electrode active material (beta type nickel oxyhydroxide).
It is desirably in the range of mass%. Further, the rare earth element in the positive electrode is more preferably in the range of 0.1 to 3.0% by mass based on the positive electrode active material (beta-type nickel oxyhydroxide). Here, “mass%” is a percentage of the total mass of the rare earth element present in the rare earth element compound with respect to the total mass of the positive electrode active material.

The average particle size of the rare earth element compound is 10 to 50.
It is desirably within the range of μm. When the average particle size is within this range, there is an advantage that the rare earth element compound is easily dispersed in the positive electrode.

The particle size distribution of the rare earth element compound is from 1 to 100.
It is desirably within the range of μm. If the particle size distribution is within this range, there is an advantage that the rare earth element compound is easily dispersed in the positive electrode.

In a conventional nickel-zinc battery, that is, a nickel-zinc battery using nickel oxyhydroxide as a positive electrode active material, when the battery is stored for a long time, the nickel oxyhydroxide reacts with the alkali in the electrolytic solution and oxygen gas Occurs. This reaction is a self-discharge reaction in the battery because nickel oxyhydroxide is reduced to nickel hydroxide, and the discharge time of the battery decreases when stored for a long time even if it can be discharged for a long time immediately after production. I do.

According to the present embodiment, Ca, M
By adding an alkaline earth metal compound such as g, Sr, Ba or a rare earth element compound such as Y, Yb, Er, Gd, the reaction between beta-type nickel oxyhydroxide and potassium hydroxide is suppressed, and oxygen gas is added. The generation speed decreases. As a result, the self-discharge of the battery is reduced, and a battery having a high discharge capacity retention rate even when stored for a long time and having excellent storage characteristics can be supplied.

In the above-described embodiment of the present invention, a description has been given of a beta-type nickel oxyhydroxide having a substantially spherical shape as the positive electrode active material. However, this beta-type nickel oxyhydroxide has a substantially spherical shape. The present invention is not limited to this, and the present invention can be applied to any other shapes.

In the above-described embodiment, the case where only one component of the beta-type nickel oxyhydroxide is used as the positive electrode active material has been described. It is a matter of course that other components such as manganese dioxide may coexist with the beta-type nickel oxyhydroxide.

In the embodiment of the invention described above, a nickel-zinc battery as a primary battery has been described. However, the present invention is not limited to this primary battery, and a nickel-zinc battery as a secondary battery is also applicable. Of course, the present invention can be applied.

In the embodiment of the invention described above, a nickel-zinc battery having a cylindrical shape is described. However, the present invention is not limited to this nickel-zinc battery. Of course, the present invention can be applied. Further, the battery size is not particularly limited. In addition, the present invention is not limited to the above-described embodiment, but can adopt various other configurations without departing from the gist of the present invention.

Next, beta-type nickel oxyhydroxide containing at least one of magnesium, calcium, strontium and barium, a method for producing the same, a positive electrode active material containing the beta-type nickel oxyhydroxide, An embodiment of the invention relating to a nickel zinc battery using a positive electrode active material will be described.

First, the configuration of the nickel zinc battery of the present invention will be described. FIG. 2 is a longitudinal sectional view showing another configuration example of the nickel zinc battery according to the present embodiment. That is, the nickel-zinc battery is a beta-type nickel oxyhydroxide (β-Ni) containing at least one element of magnesium, calcium, strontium, and barium.
A battery having a positive electrode using OOH) as a positive electrode active material and a negative electrode using zinc as a negative electrode active material.

Specifically, this nickel zinc battery 1
A battery can 2, a positive electrode 3, a separator 4, a negative electrode 5, a sealing member 6, a washer 7, a negative electrode terminal plate 8, and a current collecting pin 9 are provided.

The positive electrode 3 has a hollow cylindrical shape, and contains beta-type nickel oxyhydroxide containing at least one element of magnesium, calcium, strontium, and barium, graphite powder as a conductive agent, Positive electrode pellets 3 a, 3 b, and 3 c formed by molding a positive electrode mixture composed of an aqueous solution of potassium hydroxide as a liquid into a hollow cylindrical shape are laminated inside the battery can 2.

Another configuration of the nickel zinc battery 1 is that the nickel zinc battery described above, that is, a positive electrode containing beta type nickel oxyhydroxide and an alkaline earth metal compound, or a beta type nickel oxyhydroxide and a rare earth element compound The positive electrode is the same as that of the nickel zinc battery used.

Next, the beta-type nickel oxyhydroxide as the positive electrode active material of the present invention will be described. The beta type nickel oxyhydroxide of the present invention contains at least one element of magnesium, calcium, strontium, and barium. This magnesium, calcium,
The content of at least one of strontium and barium is desirably in the range of 0.01 to 30% by mass in total. Also, this magnesium, calcium,
More preferably, the content of one or more elements of strontium and barium is in the range of 0.05 to 20% by mass in total.

It is preferable that magnesium, calcium, strontium, or barium is dissolved in beta-type nickel oxyhydroxide. The magnesium content is represented by the magnesium content, and the magnesium content (% by mass) = {magnesium content / (nickel content + magnesium content)} × 100. The contents of calcium, strontium, and barium are represented by calcium content, strontium content, and barium content, respectively. The calcium, strontium and barium contents are defined by the same formula as for the magnesium content.

The beta type nickel oxyhydroxide of the present invention has a substantially spherical particle shape. The degree of the substantially spherical shape is the same as that of the above-mentioned substantially spherical beta-type nickel oxyhydroxide. In other words, the shape is substantially the same as the shape described in FIG. 3A. That is, the surface of most particles of the beta-type nickel oxyhydroxide of the present invention has a sharp corner and is relatively smooth. Some of the particles have a slightly elongated shape or a slightly flat shape, but have a substantially spherical shape as a whole.

The average particle size of the beta-type nickel oxyhydroxide of the present invention is preferably in the range of 5 to 30 μm. This is because when the content is within this range, the contact area between the particles increases, and there is an advantage that the reactivity is improved. The particle size distribution of the beta-type nickel oxyhydroxide of the present invention is desirably in the range of 1 to 60 μm.

The beta-type nickel oxyhydroxide of the present invention has a tap density of 1.8 to 2.7 (g / cm ³ ) and a bulk density of 1.4 to 2.2 (g / cm ³ ). Desirably.

Next, a method for producing the beta-type nickel oxyhydroxide of the present invention will be described. The method for producing beta-type nickel oxyhydroxide includes the following two steps.

In the first step, an alkaline aqueous solution is added to a nickel salt aqueous solution containing at least one metal salt of a magnesium salt, a calcium salt, a strontium salt and a barium salt to form magnesium, calcium, strontium and barium. A nickel hydroxide containing one or more of these elements is synthesized.

In the method for producing beta-type nickel oxyhydroxide containing magnesium or the like of the present invention, magnesium or the like is contained at the time of beta-type nickel hydroxide. Beta-type nickel hydroxide is prepared by dissolving a nickel salt such as nickel sulfate or nickel nitrate in water to prepare a nickel salt aqueous solution having a predetermined concentration, and mixing with an alkaline aqueous solution such as a sodium hydroxide aqueous solution or a potassium hydroxide aqueous solution. As a result, insoluble nickel hydroxide is produced by a neutralization reaction.

Thereafter, the nickel hydroxide is washed with water to remove unnecessary by-product salts, and further dried to produce the product. At this time, beta-type nickel hydroxide containing magnesium or the like can be obtained by previously dissolving a salt such as magnesium sulfate in water together with a nickel salt.

The nickel hydroxide obtained in the first step has a substantially spherical particle shape. The tap density is preferably 1.8 to 2.7 (g / cm ³ ), and the bulk density is preferably 1.4 to 2.2 (g / cm ³ ).

Next, in the second step, the nickel hydroxide obtained in the first step is oxidized in an alkaline liquid phase containing an oxidizing agent composed of hypochlorite such as sodium hypochlorite. Synthesizes beta-type nickel oxyhydroxide. That is, a method of oxidizing nickel hydroxide in a liquid phase containing a suitable oxidizing agent such as sodium hypochlorite and a suitable alkali species such as lithium hydroxide, sodium hydroxide and potassium hydroxide (chemical oxidation method). ), Nickel oxyhydroxide is synthesized in the process, irrespective of beta type or gamma type, the above-mentioned impurity ions flow out into the synthetic liquid phase and are removed to some extent from the crystal, resulting in less self-discharge. A nickel oxyhydroxide more suitable for an active material for a primary battery is obtained. Incidentally, the oxidation reaction at this time is as follows. 2Ni (OH) ₂ + C
10 ⁻ → 2NiOOH + Cl ⁻ + H ₂ O At this time, the generated nickel oxyhydroxide varies depending on the pH in the liquid phase. That is, by adjusting the pH to a predetermined value, high-density beta-type nickel oxyhydroxide is generated.

Next, the positive electrode reaction, the negative electrode reaction, the total reaction, and the theoretical starting force in a general nickel zinc battery will be described, and the internal resistance in the nickel electrode will increase.
The mechanism by which the capacity of the charge / discharge cycle deteriorates will be described.

The positive electrode reaction, the negative electrode reaction, the total reaction and the theoretical starting force in the nickel zinc battery are as follows. Positive electrode: NiOOH + H ₂ O + e ⁻ → Ni (OH) ₂ + O
H ^- E ₀ = 0.49V negative ^{electrode: Zn + 2OH - → ZnO +} H 2 O + 2e - E 0 = -1.25V all _{reaction: 2NiOOH + Zn + H 2 O} → 2Ni (OH)
₂ + ZnO Theoretical starting force: E ₀ = 1.74 V As described above, nickel hydroxide and zinc oxide are generated from nickel oxyhydroxide and zinc by the discharge reaction.

On the other hand, in a nickel-zinc battery using beta-type nickel oxyhydroxide as a positive electrode active material, it is important to suppress the generation of gamma-type nickel oxyhydroxide during charging, particularly during overcharging, in order to prevent capacity deterioration due to charge / discharge cycles. It is important to prevent.

Generally, protons in the beta-type nickel hydroxide react with hydroxyl ions in the electrolytic solution to generate water at the nickel electrode by a charging reaction. These protons move in the crystal, and the diffusion rate that indicates the ease of movement is determined by whether they can move freely in the crystal lattice.If the diffusion rate is low, gamma, which is a higher order oxide This results in the production of a large amount of nickel oxyhydroxide.

The true density of gamma type nickel oxyhydroxide is 3.79 g / cm ^3, which is smaller than the true density of beta type nickel oxyhydroxide of 4.68 g / cm ³ , causing volume expansion. On the other hand, when this gamma-type nickel oxyhydroxide is discharged, alpha-type nickel hydroxide is generated, and the true density becomes 2.82 g / cm ³ , causing further volume expansion. Due to such volume expansion, the internal resistance in the nickel electrode increases, and the capacity of the charge / discharge cycle deteriorates.

On the other hand, the present invention provides a gamma-type nickel oxyhydroxide by using a beta-type nickel oxyhydroxide containing at least one element of magnesium, calcium, strontium and barium as a positive electrode active material. Electrode expansion due to generation can be suppressed, and capacity deterioration due to charge / discharge cycles can be significantly improved.

That is, in the case of the beta-type nickel oxyhydroxide containing magnesium or the like of the present invention, defects are formed in the crystal, and the distortion of the crystal increases the freedom of protons and increases the diffusion rate. Therefore, volume expansion due to generation of gamma-type nickel oxyhydroxide can be suppressed, and capacity deterioration due to charge / discharge cycles can be improved.

In the above-described embodiment of the present invention, a description has been given of a beta-type nickel oxyhydroxide having a substantially spherical shape as the positive electrode active material. However, this beta-type nickel oxyhydroxide has a substantially spherical shape. The present invention is not limited to this, and the present invention can be applied to any other shapes.

Further, in the above-described embodiment, the case where only one component of beta-type nickel oxyhydroxide is used as the positive electrode active material has been described. It is a matter of course that other components such as manganese dioxide may coexist with the beta-type nickel oxyhydroxide.

In the embodiment of the invention described above, a nickel zinc battery as a secondary battery has been described. However, the present invention is not limited to this secondary battery, and a nickel zinc battery as a primary battery is also applicable. Of course, the present invention can be applied.

In the above-described embodiments of the present invention, a cylindrical nickel-zinc battery is described. However, the present invention is not limited to this cylindrical zinc-zinc battery. Of course, the present invention can be applied. Further, the battery size is not particularly limited.

The present invention is not limited to the above-described embodiment, but can adopt various other configurations without departing from the gist of the present invention.

[0090]

Next, specific examples of the present invention will be described. First, a battery positive electrode containing beta-type nickel oxyhydroxide and an alkaline earth metal compound, or a battery positive electrode containing beta-type nickel oxyhydroxide and a rare earth element compound, and a nickel zinc battery using these battery positive electrodes are described. An example will be described. However, it goes without saying that the present invention is not limited to these examples.

First, a method of manufacturing a sample used in this embodiment will be described. First, beta-type nickel oxyhydroxide is synthesized. That is, first, an aqueous solution of sodium hydroxide or potassium hydroxide is added to and mixed with an aqueous solution of nickel sulfate or nickel nitrate to synthesize insoluble nickel hydroxide. Thereafter, the nickel hydroxide is washed with water to remove unnecessary by-product salts, and further dried. The nickel hydroxide obtained by this step has a substantially spherical particle shape.

Next, the above-obtained nickel hydroxide is oxidized in an alkaline liquid phase containing an oxidizing agent composed of hypochlorite such as sodium hypochlorite to synthesize beta-type nickel oxyhydroxide. I do. The beta-type nickel oxyhydroxide obtained by this step has a substantially spherical particle shape. The tap density is 2.5 g / cm ³ , the bulk density is 2.0 g / cm ³ , the average particle size is 20 μm, and the particle size distribution is 5 to 70 μm.

Next, an AA nickel-zinc battery was manufactured using the above-mentioned beta-type nickel oxyoxide. First, the beta-type nickel oxyhydroxide obtained above,
An alkaline earth metal compound or a rare earth compound,
A predetermined amount was weighed and mixed using a Loedige mixer.

Next, beta-type nickel oxyhydroxide mixed with the alkaline earth metal compound or the rare earth element compound obtained as described above, and graphite powder (average particle size: 6 μm, particle size distribution: 1 to 25 μm, ash content of 0.1 μm). Using β-type nickel oxyhydroxide mixed powder: graphite powder: potassium hydroxide aqueous solution in a mass ratio of 8% by using a high-purity powdered graphite (3% by mass or less) and a potassium hydroxide aqueous solution (40% by mass), respectively.
The mixture was mixed with an impeller or a ball mill at a ratio of 6: 8: 6 to obtain a positive electrode mixture. This positive electrode mixture was pressurized under the same conditions, and formed into a hollow cylinder to produce a positive electrode. And
This positive electrode was inserted inside the battery can 2 as shown in FIG.

Next, a separator made of a nonwoven fabric (a polyolefin-based separator subjected to hydrophilization treatment) was inserted into the inside of the positive electrode, and 1.5 g of an aqueous potassium hydroxide solution was injected, followed by zinc powder, a gelling agent, and water. Potassium oxide aqueous solution 6
5 g of a negative electrode 5 prepared by adding a trace amount of an additive to a mixture of 5: 1: 34 was filled.

Finally, the opening of the battery can 2 is sealed by a sealing member 6 to which a washer 7 and a collecting pin 9 are attached, so that a cylindrical AA nickel-zinc battery 1 (alkaline) having an inside-out structure is provided. Battery).

Next, a specific sample used in this embodiment will be described. First, samples were prepared by changing the types of the alkaline earth metal compound and the rare earth element compound while keeping the addition concentration constant. The alkaline earth metal compound and the rare earth element compound added to the positive electrode are as shown in Table 1. As alkaline earth metal compounds,
These are hydroxides and oxides of Ca, Mg, Sr, and Ba. As the rare earth element compounds, Y, Yb, E
r and an oxide of Gd.

The addition concentration of the alkaline earth metal compound and the rare earth element compound is 1.0% by mass as the alkaline earth metal or the rare earth element with respect to the positive electrode active material. Using the positive electrode to which the alkaline earth metal compound or the rare earth element compound was added, a nickel zinc battery sample was produced by the above-described method. In order to compare the effects of the battery according to this example, a battery using a positive electrode to which neither an alkaline earth metal compound nor a rare earth element compound was added was manufactured.

[0099]

[Table 1]

Next, samples were prepared in which the addition concentrations of the alkaline earth metal compound and the rare earth element compound were finely changed. The alkaline earth metal compound and the rare earth element compound added to the positive electrode are as shown in Table 2. Alkaline earth metal compounds include Ca hydroxides and oxides. As the rare earth element compound, Y
Is an oxide of The addition concentration of the alkaline earth metal compound and the rare earth element compound is 0.05% as the alkaline earth metal or the rare earth element with respect to the positive electrode active material.
It was finely changed within a range of 3.5% by mass. Using the positive electrode to which the alkaline earth metal compound or the rare earth element compound was added, a nickel zinc battery sample was produced by the above-described method. In order to compare the effects of the battery according to this example, a battery using a positive electrode to which neither an alkaline earth metal compound nor a rare earth element compound was added was manufactured.

[0101]

[Table 2]

Next, a method for evaluating the battery sample manufactured as described above will be described. That is, the characteristics of the battery manufactured as described above were evaluated under two types of conditions.
As a first condition, a discharge time until reaching a discharge end voltage of 1.0 V at a constant power discharge of 1.5 W in an atmosphere of 20 ° C. was measured immediately after the battery was manufactured. Next, as a second condition, the battery was stored in a 60 ° C. atmosphere for 20 days, and then stored at 20 ° C.
After returning to the atmosphere, the discharge time was measured until the discharge end voltage reached 1.0 V at a constant power discharge of 1.5 W. Further, the self-discharge rate was calculated based on the discharge time under these two conditions.

Tables 1 and 2 show the results of the discharge time immediately after the production of the battery, the discharge time after storage, and the self-discharge rate for each sample.
First, look at Table 1. Table 1 shows that the positive electrode contains 1.0% by mass of an alkaline earth metal compound or a rare earth element compound.
This is the case when added.

Looking at the discharge time immediately after the preparation of the battery, the discharge time was 48 minutes when nothing was added, whereas when the alkaline earth metal compound or the rare earth element compound was added, the discharge time was 48 minutes. The time has changed little with 46 minutes.

Next, looking at the discharge time after storage at 60 ° C. for 20 days, when nothing was added, the storage deterioration was remarkable compared to the discharge time of 26 minutes and the discharge time of 48 minutes immediately after the production of the battery. On the other hand, when the alkaline earth metal compound or the rare earth element compound was added, storage deterioration was suppressed as compared with the discharge time of 36 minutes, which was 46 minutes immediately after the battery was manufactured.

Looking at the self-discharge rate, when no additive was added, the self-discharge rate was 46%, indicating that the storage deterioration was remarkable. On the other hand, when no alkaline earth metal compound or rare earth element compound was added, Has a self-discharge rate of 22% and storage deterioration is suppressed.

From these facts, it is possible to obtain a nickel zinc battery having excellent storage characteristics by using a positive electrode containing 1.0% of an alkaline earth metal compound or a rare earth element compound.

Next, the results in Table 2 will be examined. Table 2 shows the case where the addition concentration of the alkaline earth metal compound or the rare earth element compound was changed.

First, the hydroxide of Ca (calcium hydroxide) will be examined. Looking at the discharge time immediately after battery production, the discharge time was 48 minutes when nothing was added, whereas when calcium hydroxide was added, as the concentration of added calcium hydroxide increased, The discharge time gradually decreased from 48 minutes to 32 minutes. Here, the standard of the discharge time immediately after the production of the battery is as follows. That is, the discharge time of 8 when nothing is added is
If it is 0% or more, it is determined to be satisfactory. Here, since the discharge time when nothing is added is 48 minutes,
If it is 38.4 minutes or more, which is 80% of the above, it is satisfactory. Then, the added concentration of calcium hydroxide becomes 0.
It is desirable that the content be in the range of 0.05 to 3.10% by mass.

Next, the discharge time after storage at 60 ° C. for 20 days will be examined. If nothing was added, the discharge time was 26
On the other hand, when calcium hydroxide was added, the discharge time increased from 26 minutes to 36 minutes and further decreased to 20 minutes as the added concentration increased. While the discharge time without any addition is 26 minutes,
When the concentration of calcium hydroxide added is in the range of 0.08 to 3.10% by mass, the discharge time is as long as 28 to 36 minutes. Therefore, the concentration of calcium hydroxide added is 0.0
It is desirable to be within the range of 8 to 3.10% by mass. Furthermore, the addition concentration of calcium hydroxide is 0.10 to
When it is within the range of 3.00% by mass, the discharge time is as long as 36 minutes. Therefore, it is more desirable that the concentration of calcium hydroxide be in the range of 0.10 to 3.00% by mass.

Next, the self-discharge rate will be examined. When nothing was added, the self-discharge rate was 46%, whereas when calcium hydroxide was added, the self-discharge rate decreased from 46% to 22% as the added concentration increased. It has further increased to 38%. While the self-discharge rate in the case where nothing is added is 46%, the self-discharge rate is as low as 22 to 42% when the added concentration of calcium hydroxide is in the range of 0.08 to 3.50% by mass. Value. Therefore, the concentration of calcium hydroxide added is 0.08 to
It is desirable to be within the range of 3.50% by mass. Furthermore, the addition concentration of calcium hydroxide is 0.10 to 3.0.
When it is within the range of 0% by mass, the self-discharge rate is 22 to 25%.
And very low values. Therefore, it is more desirable that the concentration of calcium hydroxide be in the range of 0.10 to 3.00% by mass.

The above case of adding calcium hydroxide is comprehensively judged. That is, in the above-described discharge time immediately after battery production, discharge time after storage at 60 ° C. for 20 days, and evaluation of the self-discharge rate, a range common to each of the desired ranges of the additive concentration is an optimum range. And As a result, the concentration of calcium hydroxide added was 0.08.
It is desirably in the range of 3.10% by mass. Furthermore, the addition concentration of calcium hydroxide is 0.10 to 3.
More preferably, it is within the range of 00% by mass.

Next, oxides of calcium (calcium oxide)
Let's take a look at Looking at the discharge time immediately after battery fabrication,
When nothing was added, the discharge time was 48 minutes, whereas when calcium oxide was added, the discharge time gradually decreased from 46 minutes to 26 minutes as the added concentration of calcium oxide increased. are doing. Here, it is assumed that the discharge time is satisfactory if it is 80% or more of the discharge time when nothing is added. Here, the discharge time in the case where nothing is added is 48 minutes, so that 80% of the discharge time is 38.4.
Minutes or more will be satisfactory. Then, it is desirable that the addition concentration of calcium oxide be in the range of 0.05 to 3.00% by mass.

Next, the discharge time after storage at 60 ° C. for 20 days will be examined. If nothing was added, the discharge time was 26
On the other hand, when calcium oxide is added, the discharge time increases from 26 minutes to 36 minutes and further decreases to 20 minutes as the added concentration increases. While the discharge time without any addition is 26 minutes,
The addition concentration of calcium oxide is 0.08 to 3.00 mass%
, The discharge time is as long as 28 to 36 minutes.
Therefore, the concentration of calcium oxide added is 0.08 to
It is desirable to be within the range of 3.00% by mass. Furthermore, the addition concentration of calcium hydroxide is 0.10 to 3.0.
When the content is within the range of 0% by mass, the discharge time is as long as 36 minutes. Therefore, it is more desirable that the concentration of calcium oxide be in the range of 0.10 to 3.00% by mass.

Next, the self-discharge rate will be examined. When nothing was added, the self-discharge rate was 46%, whereas when calcium oxide was added, the self-discharge rate decreased from 43% to 18% as the added concentration increased. It has increased to 23%. While the self-discharge rate in the case where nothing is added is 46%, the self-discharge rate is as low as 18 to 43% when the added concentration of calcium hydroxide is in the range of 0.05 to 3.50% by mass. Value. Therefore, the addition concentration of calcium hydroxide is 0.05-3.
It is desirable to be within the range of 50% by mass. Further, when the added concentration of calcium oxide is in the range of 0.10 to 3.50 mass%, the self-discharge rate is a very low value of 18 to 23%. Therefore, it is more desirable that the concentration of calcium hydroxide be in the range of 0.10 to 3.50% by mass.

The above case of adding calcium oxide is comprehensively determined. In other words, in the above-described evaluation of the discharge time immediately after battery production, the discharge time after storage at 60 ° C. for 20 days, and the self-discharge rate, a range common to each of the desired ranges of the additive concentration is an optimum range. And As a result, the concentration of calcium oxide added was 0.08 to
It is desirable to be within the range of 3.00% by mass. Further, the concentration of calcium oxide added is 0.10 to 3.00.
More desirably, it is in the range of mass%.

The case where the above-mentioned calcium hydroxide and calcium oxide are added, that is, the case where a calcium compound which is one of the alkaline earth metal compounds is added is comprehensively judged. That is, in the above-described evaluation of calcium hydroxide and calcium oxide, a range common to each other among the desired ranges of the addition concentration is set as an optimum range. As a result, the concentration of the calcium compound added is preferably in the range of 0.08 to 3.00% by mass. Still more preferably, the concentration of the calcium compound added is in the range of 0.10 to 3.00% by mass.

Next, an oxide of Y (yttrium oxide)
Let's take a look at Looking at the discharge time immediately after battery fabrication,
When nothing was added, the discharge time was 48 minutes. On the other hand, when yttrium oxide was added, the discharge time was 4 as the added concentration of yttrium oxide increased.
It gradually decreased from 8 minutes to 32 minutes. Here, it is assumed that the discharge time is satisfactory if it is 80% or more of the discharge time when nothing is added. Here, since the discharge time when nothing is added is 48 minutes, 80% of the discharge time is 3%.
If it is 8.4 minutes or more, it will be satisfactory. Then, the addition concentration of yttrium oxide is 0.05 to 3.10.
It would be desirable to be in the range of mass%.

Next, the discharge time after storage at 60 ° C. for 20 days will be examined. If nothing was added, the discharge time was 26
On the other hand, when yttrium oxide is added, the discharge time increases from 26 minutes to 36 minutes and further decreases to 20 minutes as the addition concentration increases. While the discharge time without any addition is 26 minutes,
When the addition concentration of yttrium oxide is in the range of 0.08 to 3.10% by mass, the discharge time is as long as 28 to 36 minutes. Therefore, the addition concentration of yttrium oxide is 0.0
It is desirable to be within the range of 8 to 3.10% by mass. Further, the concentration of yttrium hydroxide added is 0.10 to 0.10.
When it is within the range of 3.00% by mass, the discharge time is as long as 36 minutes. Therefore, the addition concentration of yttrium oxide is more preferably in the range of 0.10 to 3.00 mass%.

Next, the self-discharge rate will be examined. When nothing is added, the self-discharge rate is 46%, whereas when yttrium oxide is added, the self-discharge rate decreases from 46% to 22% as the added concentration increases. It has increased to 38%. While the self-discharge rate in the case where nothing is added is 46%, the self-discharge rate is as low as 22 to 42% when the addition concentration of yttrium hydroxide is in the range of 0.08 to 3.50 mass%. Value.
Therefore, the additive concentration of yttrium hydroxide is 0.08
It is desirably within the range of 3.5% by mass. Furthermore, the addition concentration of yttrium oxide is 0.10-3.
When the content is within the range of 00% by mass, the self-discharge rate is 22 to 25.
% Is a very low value. Therefore, the addition concentration of yttrium hydroxide is more preferably in the range of 0.10 to 3.00% by mass.

The above case of yttrium oxide addition is comprehensively determined. That is, in the above-described discharge time immediately after battery production, discharge time after storage at 60 ° C. for 20 days, and evaluation of the self-discharge rate, a range common to each of the desired ranges of the additive concentration is an optimum range. And As a result, the added concentration of yttrium oxide was 0.08
It is desirably in the range of 3.10% by mass. Furthermore, the addition concentration of yttrium oxide is 0.10-3.
More preferably, it is within the range of 00% by mass.

In Table 2, the elements listed as alkaline earth metal compounds and rare earth element compounds are C
a, Y, but other Mg, Sr, Ba, Yb, Er,
Similar results were obtained when the compound of Gd was added.

As described above, according to the present embodiment, by adding an alkaline earth metal compound such as Ca, Mg, Sr and Ba or a rare earth element compound such as Y, Yb, Er and Gd to the positive electrode. In addition, the reaction between beta-type nickel oxyhydroxide and potassium hydroxide is suppressed, and the oxygen gas generation rate decreases. As a result, the self-discharge of the battery is reduced, and a battery having a high discharge capacity retention rate even when stored for a long time and having excellent storage characteristics can be supplied. Here, the addition concentration of the alkaline earth metal compound is desirably in the range of 0.08 to 3.00 mass%. Still more preferably, the concentration of the added alkaline earth metal compound is in the range of 0.10 to 3.00% by mass. Further, it is desirable that the concentration of the rare earth element compound be in the range of 0.08 to 3.10% by mass. Still more preferably, the concentration of the rare earth element compound added is in the range of 0.10 to 3.00% by mass.

Next, beta-type nickel oxyhydroxide containing at least one of magnesium, calcium, strontium and barium, a method for producing the same, a positive electrode active material containing the beta-type nickel oxyhydroxide, and a positive electrode active material containing the same. An example according to a nickel zinc battery using a positive electrode active material will be described. However, it goes without saying that the present invention is not limited to these examples.

First, a method for manufacturing a sample in this embodiment will be described. Example 1 First, beta-type nickel oxyhydroxide containing magnesium was synthesized. That is, first, an aqueous solution of sodium hydroxide or potassium hydroxide is added to and mixed with an aqueous solution of nickel sulfate or nickel nitrate containing a predetermined amount of magnesium sulfate to synthesize insoluble nickel hydroxide containing magnesium. Thereafter, the nickel hydroxide is washed with water to remove unnecessary by-product salts, and further dried to produce the nickel hydroxide. The nickel hydroxide obtained by this step has a substantially spherical particle shape.

Next, the nickel hydroxide obtained above is oxidized in an alkaline liquid phase containing an oxidizing agent composed of hypochlorite such as sodium hypochlorite to synthesize beta-type nickel oxyhydroxide. I do. The beta-type nickel oxyhydroxide obtained by this step has a substantially spherical particle shape. The obtained beta-type nickel oxyoxide contains 0.01% by mass of magnesium.

Next, an AA nickel-zinc battery was manufactured using the above-mentioned beta-type nickel oxyoxide. That is, the beta-type nickel oxyhydroxide obtained above and graphite powder (average particle size: 6 μm, particle size distribution: 1 to 25)
Using beta-nickel oxyhydroxide: graphite powder: potassium hydroxide aqueous solution: 10: 1: μm, high-purity powdered graphite having an ash content of 0.3% by weight or less and potassium hydroxide aqueous solution (40% by weight). The mixture was mixed at a ratio of 1 to obtain a positive electrode mixture, which was 10 g in an outer diameter of 13.3 and an inner diameter of 9.0 m in a battery can.
m, and formed into a hollow cylindrical shape having a height of 40 mm.

Next, a non-woven fabric separator (a hydrophilized polyolefin-based separator) was inserted into the inside of the positive electrode, and 1.5 g of an aqueous potassium hydroxide solution was injected, followed by zinc powder, a gelling agent, and water. Potassium oxide aqueous solution 6
5 g of a negative electrode prepared by adding a trace amount of an additive to a mixture of 5: 1: 34 was filled. Finally, the opening of the battery can was sealed with a sealing member to which a spring and a collecting pin were attached, to produce an AA nickel-zinc battery (alkaline battery) having an inside-out structure.

Examples 2 to 9 As examples 2 to 9, as shown in Table 3, 0.05 mass% and 0.1 mass% of magnesium were added to beta-type nickel oxyhydroxide, respectively.
0.5 mass%, 1 mass%, 5 mass%, 10 mass%, 20
What contained 30 mass% and 30 mass% was used as a positive electrode active material. What are the other conditions? This is similar to the first embodiment.

Examples 10 to 18 As Examples 10 to 18, as shown in Table 4, 0.01 mass%, 0.05 mass%, and 0.1 mass% of calcium were added to beta-type nickel oxyhydroxide, respectively. %, 0.5% by mass, 1% by mass, 5% by mass, 10% by mass, 20% by mass, and 30% by mass were used as the positive electrode active material. What are the other conditions? This is similar to the first embodiment.

Examples 19 to 27 As Examples 19 to 27, as shown in Table 5, strontium was added to beta-type nickel oxyhydroxide by 0.01% by mass and 0.0% by mass, respectively.
5% by mass, 0.1% by mass, 0.5% by mass, 1% by mass, 5% by mass
Those containing 10% by mass, 10% by mass, 20% by mass, and 30% by mass were used as the positive electrode active material. What are the other conditions?
This is similar to the first embodiment.

Examples 28 to 36 As Examples 28 to 36, as shown in Table 6, 0.01% by mass, 0.05% by mass and 0.1% by mass of barium were added to beta-type nickel oxyhydroxide, respectively. %, 0.5% by mass, 1% by mass, 5% by mass, 10% by mass, 20% by mass, and 30% by mass were used as the positive electrode active material. What are the other conditions? This is similar to the first embodiment.

[Conventional Example] In order to confirm the effects of Examples 1 to 36, beta-type nickel oxyhydroxide containing no magnesium, calcium, strontium and barium was used as a positive electrode active material. What are the other conditions? This is similar to the first embodiment.

Next, the nickel zinc batteries produced in Examples 1 to 36 and the conventional example were subjected to a charge / discharge test to examine a capacity retention ratio by a charge / discharge cycle.

In the charge / discharge test, the cycle of discharging 10 batteries in each of the examples and the conventional example at a current of 100 mA until the voltage reaches 1 V, and then charging until the voltage reaches 1.9 V is defined as one cycle. The capacity retention rates after 100 cycles were compared.

The capacity retention ratio is a ratio (%) to the initial discharge capacity and is expressed by the following equation. 100th cycle capacity retention rate (%) = [(100th cycle discharge capacity) / (initial discharge capacity)] × 100

Further, the theoretical discharge capacity was calculated. The theoretical discharge capacity at which charging and discharging can be actually performed was calculated on the assumption that the amount of nickel was reduced by the amount of magnesium or the like contained in the positive electrode active material of the battery of this example. At this time, the theoretical discharge capacity of the conventional battery not containing magnesium or the like was 10
Set to 0.

Table 3 shows the measurement results of the capacity retention (%) and the theoretical discharge capacity of Examples 1 to 9 and the conventional example. FIG. 4 illustrates the capacity retention ratio (%) in Examples 1 to 9 and the conventional example.

[0139]

[Table 3]

Let us look at the capacity retention ratio in Table 3. In the case of the conventional example, that is, when the beta-type nickel oxyhydroxide containing no magnesium was used, the capacity retention ratio was 50%, whereas Examples 1 to 9, ie, 0.01 to 30 mass of magnesium was used. %, The capacity retention rate is 5%.
It shows a high value of 2 to 92%. When the magnesium content is less than 0.01% by mass, it is considered that gamma-type nickel oxyhydroxide is generated. From this, it is desirable that the magnesium contained in the beta-type nickel oxyhydroxide be in the range of 0.01 to 30% by mass.

Further, the capacity retention ratio in Table 3 will be examined. When the magnesium content is 0.01% by mass, the capacity retention ratio is 52.
%, Whereas when the magnesium content is 0.05% by mass, the capacity retention ratio rapidly increases to 75%. Thereafter, the magnesium content is reduced from 0.05% by mass to 20%.
It increases monotonically from 75% to 92% with increasing mass%. In addition, the magnesium content is 30
In the case of mass%, the magnesium content shows the same value as the capacity maintenance ratio of 92% at 20 mass%. Here, if the capacity retention rates are the same, the lower the magnesium content, the more desirable. Since magnesium does not participate in the charge / discharge reaction of the battery, when the content of magnesium is more than 20% by mass, the amount of nickel is reduced by the added amount. This is because the amount of nickel charged as a battery decreases, and the initial capacity decreases. From this, the magnesium contained in the beta-type nickel oxyhydroxide was 0.0%
More preferably, it is in the range of 5 to 20% by mass.

Table 4 shows the measurement results of the capacity retention (%) and the theoretical discharge capacity of Examples 10 to 18. FIG. 4 shows the capacity retention ratio (%) for Examples 10 to 18.

[0143]

[Table 4]

As described above, in the conventional example, that is, when the beta-type nickel oxyhydroxide containing no calcium is used, the capacity retention ratio is 50%, whereas the examples 10 to 18 are used. 0.01 calcium
When the beta-type nickel oxyhydroxide contained in the range of 30 to 30% by mass is used, the capacity retention ratio is 51 to 88%.
It shows a high value. From this, calcium contained in beta-type nickel oxyhydroxide is 0.01 to 3
It is desirably within the range of 0% by mass.

The calcium content is 0.01% by mass.
In this case, the capacity retention rate is 51%, whereas when the calcium content is 0.05% by mass, the capacity retention rate sharply increases to 70%. Thereafter, the calcium content was 0.0
As the mass increases from 5% by mass to 20% by mass, 70%
The percentage has increased monotonically from 88% to 88%. When the calcium content is 30% by mass, the calcium content is 2%.
It shows the same value as the capacity maintenance rate of 0% by mass of 88%. Here, if the capacity retention rates are the same, it is more desirable that the calcium content rate is low. Since calcium does not participate in the charge / discharge reaction of the battery, when the content of calcium is more than 20% by mass, the amount of nickel is reduced by the added amount. As a result, the nickel loading of the battery is reduced,
This is because the initial capacity decreases. From this, the calcium contained in the beta-type nickel oxyhydroxide is 0.1%.
More preferably, it is in the range of 0.5 to 20% by mass.

Table 5 shows the measurement results of the capacity retention ratio (%) and the theoretical discharge capacity of Examples 19 to 27. FIG. 4 illustrates the capacity retention rates (%) of Examples 19 to 27.

[0147]

[Table 5]

As described above, in the conventional example, that is, when the beta-type nickel oxyhydroxide containing no strontium was used, the capacity retention ratio was 50%, whereas the examples 19 to 27, namely, When using beta-type nickel oxyhydroxide containing strontium in the range of 0.01 to 30% by mass, the capacity retention rate is 52%.
It shows a high value of up to 87%. For this reason, strontium contained in beta-type nickel oxyhydroxide is desirably in the range of 0.01 to 30% by mass.

When the strontium content is 0.01% by mass, the capacity retention ratio is 52%, whereas when the strontium content is 0.05% by mass, the capacity retention ratio sharply increases to 68%. . Thereafter, as the strontium content increases from 0.05% by mass to 20% by mass, the strontium content monotonically increases from 68% to 87%. When the strontium content is 30% by mass, the strontium content shows the same value as the capacity retention rate of 87% when the strontium content is 20% by mass. Here, if the capacity retention ratio is the same, the lower the strontium content, the more desirable. Since strontium does not participate in the charge / discharge reaction of the battery,
When the content of strontium is more than 20% by mass, the amount of nickel is reduced by the amount added. This is because the amount of nickel charged as a battery decreases, and the initial capacity decreases. From this, it is more desirable that the strontium contained in the beta-type nickel oxyhydroxide is in the range of 0.05 to 20% by mass.

The measurement results of the capacity retention ratio (%) and the theoretical discharge capacity of Examples 28 to 36 are as shown in Table 6. FIG. 4 illustrates the capacity retention rates (%) of Examples 28 to 36.

[0151]

[Table 6]

As described above, in the conventional example, that is, when the beta-type nickel oxyhydroxide containing no barium is used, the capacity retention ratio is 50%,
Examples 28 to 36, that is, 0.01 to 30 barium
When beta-type nickel oxyhydroxide contained in the range of mass% is used, the capacity retention ratio shows a high value of 51 to 88%. From this, barium contained in beta-type nickel oxyhydroxide is 0.01 to 30% by mass.
Is desirably within the range.

When the barium content is 0.01% by mass, the capacity retention ratio is 51%, whereas when the barium content is 0.05% by mass, the capacity retention ratio sharply increases to 69%. . Thereafter, as the barium content increases from 0.05% by mass to 20% by mass, it monotonically increases from 69% to 88%. When the barium content is 30% by mass, the barium content shows the same value as the capacity retention ratio of 88% at 20% by mass. Here, if the capacity retention ratio is the same, it is more desirable that the barium content is low. Since barium does not participate in the charge / discharge reaction of the battery, when the barium content is higher than 20% by mass, the amount of nickel is reduced by the added amount. This is because the nickel filling amount of the battery is reduced, and the initial capacity is reduced. For this reason, it is more desirable that the barium contained in the beta-type nickel oxyhydroxide be in the range of 0.05 to 20% by mass.

As described above, according to the present embodiment, when the content of magnesium, calcium, strontium, or barium is in the range of 0.01 to 30% by mass, the capacity deterioration in the charge / discharge cycle is significantly improved. Can be. Further, the content of magnesium, calcium, strontium, or barium contained in the beta-type nickel oxyhydroxide is more preferably in the range of 0.05 to 20% by mass.

[0155]

The present invention has the following effects. The positive electrode for a battery contains beta-type nickel oxyhydroxide and an alkaline earth metal compound, or the positive electrode for a battery contains beta-type nickel oxyhydroxide and a rare earth element compound, or beta-type oxywater which is a positive electrode active material A positive electrode obtained by pelletizing a mixed powder containing at least nickel oxide and graphite powder into a hollow cylindrical shape is disposed on the outer periphery, and a negative electrode containing zinc, which is a negative electrode active material, and an electrolytic solution is disposed at a central portion. In a nickel zinc battery in which a separator is disposed between the positive electrode and the negative electrode, the storage characteristics of the battery can be improved because the positive electrode contains an alkaline earth metal compound or a rare earth element compound.

By using a beta-type nickel oxyhydroxide containing at least one element of magnesium, calcium, strontium and barium, or
A method for producing beta-type nickel oxyhydroxide including the following steps, that is, adding an aqueous alkali solution to an aqueous nickel salt solution containing one or more metal salts of magnesium salts, calcium salts, strontium salts, and barium salts A first step of synthesizing nickel hydroxide containing at least one of magnesium, calcium, strontium and barium, and oxidizing the nickel hydroxide in an alkaline liquid phase containing hypochlorite. In the second step of synthesizing beta-type nickel oxyhydroxide, or in the positive electrode active material composed of beta-type nickel oxyhydroxide, beta-type nickel oxyhydroxide contains one of magnesium, calcium, strontium, and barium. By containing more than one type of element, or A positive electrode obtained by pelletizing a mixed powder containing at least nickel oxyhydroxide and graphite powder into a hollow cylindrical shape is provided on the outer peripheral portion, and a negative electrode containing at least a negative electrode active material of zinc and an electrolytic solution is disposed in a central portion, In a nickel zinc battery with a separator between the positive and negative electrodes,
When the beta-type nickel oxyhydroxide contains at least one element of magnesium, calcium, strontium, and barium, capacity deterioration due to charge / discharge cycles can be suppressed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a configuration example of a battery according to an embodiment.

FIG. 2 is a longitudinal sectional view showing another configuration example of the battery according to the present embodiment.

FIG. 3 shows a substantially spherical beta-type nickel oxyhydroxide (A) used as a positive electrode active material of a battery according to the present embodiment and a non-spherical beta-type nickel oxyhydroxide (A) used as a positive electrode active material of a conventional battery. It is a figure which shows B).

FIG. 4 is a diagram showing a relationship between a content rate and a capacity retention rate.

[Explanation of symbols]

1 ‥‥ nickel zinc battery, 2 ‥‥ battery can, 3 ‥‥ positive electrode,
4 ‥‥ separator, 5 ‥‥ anode, 6 ‥‥ sealing member, 7 ‥
‥ Washer, 8 ‥‥ Negative terminal plate, 9 ‥‥ Current collecting pin

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kazura Honda 2nd Hinoguchi, Motomiya-cho, Adachi-gun, Fukushima Prefecture Inside Sony Fukushima Co., Ltd. (72) Kuniyasu Oya 2nd Hinoguchi, Motomiya-cho, Adachi-gun, Fukushima Soni F term in Fukushima Corporation (reference) 4G048 AA03 AA05 AC06 AD03 AD04 5H024 AA02 AA14 CC02 DD14 DD17 EE06 FF09 HH01 HH08 HH13 5H050 AA09 BA04 CA03 CB13 DA02 DA09 DA10 EA09 EA12 FA17 HA01 HA08

Claims (40)

[Claims] 1. A battery positive electrode comprising beta-type nickel oxyhydroxide and an alkaline earth metal compound. 2. The positive electrode for a battery according to claim 1, wherein at least one compound selected from hydroxides or oxides of alkaline earth metals is added as the alkaline earth metal compound. 3. The method according to claim 2, wherein the alkaline earth metal is Ca, Mg, S
3. The positive electrode for a battery according to claim 2, wherein the positive electrode is made of at least one metal selected from r and Ba. 4. The positive electrode for a battery according to claim 3, wherein the alkaline earth metal is in a range of 0.08 to 3.0% by mass with respect to the beta-type nickel oxyhydroxide. 5. The positive electrode for a battery according to claim 4, wherein the beta-type nickel oxyhydroxide has a substantially spherical particle shape. 6. The beta-type nickel oxyhydroxide has a tap density of 2.2 to 2.7 g / cm ³ and a bulk density of 1.6 to 2.2 g / cm ^3. Item 6. A positive electrode for a battery according to Item 5. 7. A positive electrode for a battery, comprising beta-type nickel oxyhydroxide and a rare earth element compound. 8. The positive electrode for a battery according to claim 7, wherein one or more compounds selected from hydroxides or oxides of rare earth elements are added as the rare earth element compound. 9. The positive electrode for a battery according to claim 8, wherein the rare earth element comprises at least one element selected from the group consisting of Y, Yb, Er, and Gd. 10. The positive electrode for a battery according to claim 9, wherein the rare earth element is in a range of 0.08 to 3.1% by mass with respect to the beta-type nickel oxyhydroxide. 11. The positive electrode for a battery according to claim 10, wherein the beta-type nickel oxyhydroxide has a substantially spherical particle shape. 12. The beta-type nickel oxyhydroxide has a tap density of 2.2 to 2.7 g / cm ³ and a bulk density of 1.6 to 2.2 g / cm ^3. Item 12. A positive electrode for a battery according to Item 11. 13. A positive electrode obtained by forming a mixed powder containing at least beta-type nickel oxyhydroxide serving as a positive electrode active material and graphite powder into a hollow cylindrical shape, and disposing the positive electrode on the outer periphery.
In a nickel zinc battery, a negative electrode containing zinc, which is a negative electrode active material, and an electrolytic solution is disposed at the center, and a separator is disposed between the positive electrode and the negative electrode. A nickel-zinc battery, being nickel hydroxide. 14. The alkaline earth metal compound is selected from hydroxides or oxides of alkaline earth metals.
14. The nickel zinc battery according to claim 13, wherein at least two or more kinds of compounds are added. 15. The alkaline earth metal is Ca, Mg, S
The nickel-zinc battery according to claim 14, comprising one or more metals selected from r and Ba. 16. The nickel zinc battery according to claim 15, wherein the alkaline earth metal is in a range of 0.08 to 3.0% by mass with respect to the beta type nickel oxyhydroxide. 17. The nickel zinc battery according to claim 16, wherein the beta-type nickel oxyhydroxide has a substantially spherical particle shape. 18. The beta-type nickel oxyhydroxide has a tap density of 2.2 to 2.7 g / cm ³ and a bulk density of 1.6 to 2.2 g / cm ^3. Item 18. The nickel zinc battery according to Item 17. 19. A positive electrode obtained by pelletizing a mixed powder containing at least a beta-type nickel oxyhydroxide as a positive electrode active material and graphite powder into a hollow cylindrical shape is disposed on an outer peripheral portion,
In a nickel zinc battery, a negative electrode containing zinc, which is a negative electrode active material, and an electrolytic solution is disposed at the center, and a separator is disposed between the positive electrode and the negative electrode. A nickel-zinc battery, being nickel. 20. The nickel zinc battery according to claim 19, wherein at least one compound selected from a hydroxide or an oxide of the rare earth element is added as the rare earth element compound. 21. The rare earth element is Y, Yb, Er, Gd.
21. The nickel zinc battery according to claim 20, comprising at least one element selected from the group consisting of: 22. The nickel zinc battery according to claim 21, wherein the rare earth element is in a range of 0.08 to 3.1% by mass with respect to the beta type nickel oxyhydroxide. 23. The nickel zinc battery according to claim 22, wherein the beta-type nickel oxyhydroxide has a substantially spherical particle shape. 24. The beta-type nickel oxyhydroxide has a tap density of 2.2 to 2.7 g / cm ³ and a bulk density of 1.6 to 2.2 g / cm ^3. Item 24. A nickel zinc battery according to Item 23. 25. A beta-type nickel oxyhydroxide containing at least one element of magnesium, calcium, strontium and barium. 26. The beta-type nickel oxyhydroxide according to claim 25 has the following characteristics. (A) Beta-type nickel oxyhydroxide is one of magnesium, calcium, strontium, and barium.
More than one kind of elements are contained in a total amount of 0.01 to 30% by mass. 27. The beta-type nickel oxyhydroxide according to claim 26, is characterized by the following. (A) The beta-type nickel oxyhydroxide has a substantially spherical particle shape. 28. The beta-type nickel oxyhydroxide according to claim 27 is characterized by the following. (A) The beta-type nickel oxyhydroxide has a tap density of 1.8 to 2.7 (g / cm ³ ) and a bulk density of 1.4 to 2.2 (g / cm ³ ). 29. A method for producing beta-type nickel oxyhydroxide, comprising the following steps. (A) adding an aqueous alkali solution to an aqueous nickel salt solution containing at least one metal salt of a magnesium salt, a calcium salt, a strontium salt, and a barium salt to obtain one of magnesium, calcium, strontium, and barium;
First step of synthesizing nickel hydroxide containing more than one kind of element. (B) A second step of oxidizing the nickel hydroxide in an alkaline liquid phase containing hypochlorite to synthesize beta-type nickel oxyhydroxide. 30. The method for producing beta-type nickel oxyhydroxide according to claim 29, is characterized by the following. (A) Nickel hydroxide has a substantially spherical particle shape. 31. A method for producing beta-type nickel oxyhydroxide according to claim 30, characterized in that: (A) The beta-type nickel oxyhydroxide has a substantially spherical particle shape. 32. A method for producing beta-type nickel oxyhydroxide according to claim 31, characterized in that: (A) Beta-type nickel oxyhydroxide is one of magnesium, calcium, strontium, and barium.
More than one kind of elements are contained in a total amount of 0.01 to 30% by mass. 33. A positive electrode active material comprising beta-type nickel oxyhydroxide, characterized by the following. (A) Beta-type nickel oxyhydroxide is one of magnesium, calcium, strontium, and barium.
Contains more than one element. 34. The positive electrode active material according to claim 33 has the following characteristics. (A) Beta-type nickel oxyhydroxide is one of magnesium, calcium, strontium, and barium.
More than one kind of elements are contained in a total amount of 0.01 to 30% by mass. 35. The positive electrode active material according to claim 34, is characterized by the following. (A) The beta-type nickel oxyhydroxide has a substantially spherical particle shape. 36. The positive electrode active material according to claim 35, is characterized by the following. (A) The beta-type nickel oxyhydroxide has a tap density of 1.8 to 2.7 (g / cm ³ ) and a bulk density of 1.4 to 2.2 (g / cm ³ ). 37. A positive electrode obtained by forming a mixed powder containing at least a beta-type nickel oxyhydroxide serving as a positive electrode active material and graphite powder into a hollow cylindrical shape, and disposing the positive electrode on the outer periphery.
A nickel-zinc battery in which a negative electrode containing zinc, which is a negative electrode active material, and an electrolyte is disposed at a central portion, and a separator is disposed between the positive electrode and the negative electrode. (A) Beta-type nickel oxyhydroxide is one of magnesium, calcium, strontium, and barium.
Contains more than one element. 38. The nickel zinc battery according to claim 37 has the following features. (A) Beta-type nickel oxyhydroxide is one of magnesium, calcium, strontium, and barium.
More than one kind of elements are contained in a total amount of 0.01 to 30% by mass. 39. The nickel zinc battery according to claim 38, is characterized by the following. (A) The beta-type nickel oxyhydroxide has a substantially spherical particle shape. 40. A nickel zinc battery according to claim 39, characterized by the following. (A) The beta-type nickel oxyhydroxide has a tap density of 1.8 to 2.7 (g / cm ³ ) and a bulk density of 1.4 to 2.2 (g / cm ³ ).