JP3490818B2 - Paste nickel electrode for alkaline storage batteries - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paste-type nickel electrode for an alkaline storage battery, and more particularly, to an alkaline storage battery having a long charge / discharge cycle life, which has a high utilization rate of an active material and can be charged. The present invention relates to improvement of an active material for the purpose of providing a paste-type nickel electrode that is less likely to undergo volume expansion (expansion) in a discharge cycle.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
As a nickel electrode for an alkaline storage battery, a sintered nickel electrode obtained by impregnating a sintered substrate obtained by sintering nickel powder on a perforated steel plate or the like with an active material (nickel hydroxide) is well known.

In order to increase the packing density of the active material in the sintered nickel electrode, it is necessary to use a sintered substrate with high porosity. However, the bond between the nickel particles due to sintering is weak, and if the porosity of the sintered substrate is increased, the nickel powder will easily fall off from the sintered substrate. Therefore, practically, the porosity of the sintered substrate cannot be made higher than 80%, and therefore, the sintered nickel electrode has a problem that the packing density of the active material is small. Moreover, since the pore size of the sintered body of nickel powder is as small as 10 μm or less, the filling of the active material into the substrate (sintered body) must be performed by the solution impregnation method, which requires repeated complicated impregnation steps several times. There is also the problem of not becoming.

Under these circumstances, a paste type nickel electrode has recently been newly proposed. The paste type nickel electrode is produced by directly filling a kneaded material (paste) of an active material (nickel hydroxide) and a binder solution (aqueous solution of methylcellulose etc.) into a substrate having a high porosity (foamed metal etc.). Since the paste nickel electrode can use a substrate having a large porosity (the paste nickel electrode can use a substrate having a porosity of 95% or more), it is possible to increase the packing density of the active material. The active material can be charged into the substrate once.

However, when a substrate having a high porosity is used to increase the packing density of the active material in the paste type nickel electrode, the current collecting ability of the substrate becomes worse than that of the sintered substrate used in the sintering type nickel electrode. Therefore, as compared with the sintered nickel electrode, the conductivity is deteriorated and the utilization factor of the active material is reduced, and γ-NiOOH is generated during charging, and the electrode plate is likely to swell. The reduction of the active material utilization rate and the swelling of the electrode plate lead to a shortened battery life.

Therefore, in order to enhance the conductivity of the paste type nickel electrode, cobalt hydroxide powder is added to the active material powder (nickel hydroxide powder) (Japanese Patent Laid-Open No. 61-74261).
Japanese Patent Laid-Open No. 62-234), or the surface of active material particles (nickel hydroxide particles) is coated with cobalt hydroxide (JP-A-62-234).
867). Also,
In order to suppress the swelling of the paste-type nickel electrode, it has been proposed to further add a zinc compound to the active material powder to which cobalt hydroxide has been added (JP-A-4-137368).
(See Japanese Patent Publication).

However, as a result of studies by the present inventors, it has been found that it is difficult to obtain a paste-type nickel electrode which has a high utilization rate of the active material and is less likely to swell with the above-mentioned conventional technique.

The present invention has been made in view of the above circumstances, and an object thereof is to obtain an alkaline storage battery having a high utilization rate of an active material, less swelling, and a long charge / discharge cycle life. To provide the necessary paste type nickel electrode in.

[0009]

A paste type nickel electrode for an alkaline storage battery (electrode of the present invention) according to the present invention for achieving the above object has an average valence of cobalt of 2 on the surface of nickel hydroxide particles. It is characterized in that zinc or a zinc compound is added to the active material powder made of the composite particles formed by forming the coating layer made of the cobalt compound of 0.5 to 2.93 .

In the electrode of the present invention, the average valence of cobalt is 2.5 to 2.93 on the surface of the nickel hydroxide particles.
An active material powder composed of composite particles formed by forming a coating layer composed of a cobalt compound is used. Active material powder consisting of composite particles in which the surface of nickel hydroxide particles is coated with cobalt hydroxide having a divalent cobalt valence (Japanese Patent Laid-Open No. Sho 62-62).
Than using an active material powder) shown in -234867 Patent Publication, since insufficient conductivity of the particle surface, have a sufficiently high paste-type nickel electrode active material utilization rate can be obtained.

In the electrode of the present invention, zinc (powder) or zinc compound (powder) is added to the active material powder. Examples of the zinc compound include zinc oxide ( ZnO ₂ ), zinc hydroxide (Zn (OH) ₂ ), and zinc carbonate (ZnCO ₃ ). Instead of a mixture of nickel hydroxide powder and a cobalt compound, zinc or a zinc compound is added to the composite particles because the cobalt compound enhances the conductivity of the surface of the nickel hydroxide particles, and the zinc or zinc compound is added. This is because it is necessary to previously fix the cobalt compound as a coating layer on the surface of the nickel hydroxide particles in order to suppress the swelling by the addition of. That is, when zinc or a zinc compound is added to a mixture of nickel hydroxide powder and a cobalt compound (powder), the cobalt compound is likely to react with an alkaline electrolyte to change to a cobalt oxide having low conductivity. Therefore, not only a high utilization ratio of the active material cannot be obtained, but also the swelling suppressing action of zinc or a zinc compound is hindered by the produced cobalt oxide.

The weight ratio of cobalt to nickel hydroxide particles in the coating layer is preferably 1 to 20%. If this weight ratio is less than 1%, it is difficult to obtain a sufficiently high active material utilization rate because the amount of cobalt is too small. On the other hand, if this weight ratio exceeds 20%, it is directly related to the battery capacity. This is because the amount of nickel hydroxide used is reduced and the battery capacity is reduced.

The weight ratio of zinc or zinc in the zinc compound to nickel hydroxide particles is preferably 1 to 10%. If the weight ratio is less than 1%, it is difficult to sufficiently suppress swelling because the amount of zinc is too small. On the other hand, if the weight ratio exceeds 10%, the hydroxylation directly related to the battery capacity is suppressed. This is because the amount of nickel decreases and the battery capacity decreases.

The active material powder in the electrode of the present invention is, for example, powder composed of composite particles in which a coating layer composed of at least one of cobalt hydroxide, cobalt monoxide and metallic cobalt is formed on the surface of nickel hydroxide particles. It is prepared by adding an alkaline aqueous solution to the above, heat treating at a predetermined temperature for a predetermined time, washing with water, and drying. By adjusting the concentration of the alkaline aqueous solution, the heat treatment time or the heat treatment temperature, the average valence of cobalt in the cobalt compound can be adjusted.
It can be adjusted in the range of 2.5 to 2.93 . The higher the concentration of the alkaline aqueous solution, the higher the heat treatment temperature, and the longer the heat treatment time, the higher the valence of cobalt due to the progress of oxidation of the coating layer. From this fact, this reaction shows that cobalt is once divalent and is dissolved in an aqueous alkaline solution, and the dissolved divalent cobalt is deposited on the surface of the nickel hydroxide particles, and then, in the presence of alkali, it is mixed with oxygen in the air. It is thought to be a reaction and oxidation. The heat treatment temperature is generally 45 to 95 ° C, and the heat treatment time is generally 1 minute to 2 hours.

As a method for forming a coating layer made of cobalt hydroxide on the surface of nickel hydroxide particles, nickel hydroxide powder is put into an aqueous cobalt salt solution, an aqueous alkali solution is added, and the formed precipitate is filtered off. Washing with water and drying.

As a method of forming a coating layer comprising at least one of cobalt hydroxide, cobalt monoxide and metallic cobalt on the surface of nickel hydroxide particles, nickel hydroxide powder, cobalt hydroxide powder, cobalt monoxide powder and A method (mechanical charge method) in which at least one kind of metal cobalt powder is dry-mixed in an inert gas atmosphere by a compression grinding pulverizer is used.

[0017]

The nickel hydroxide particles in the present invention include
Solid solution particles in which cobalt, zinc, cadmium, calcium, manganese, magnesium, and the like are solid-dissolved in nickel hydroxide are also included.

In the present invention, cobalt compounds having an average cobalt valence of more than 2 and not more than 3 include cobalt hydroxide (cobalt valence: 2) and cobalt oxyhydroxide (cobalt valence: 3). Of various ratios and cobalt oxyhydroxide.

The electrode of the present invention comprises an active material powder composed of composite particles, which is formed by forming a coating layer composed of a cobalt compound having an average cobalt valence of more than 2 and not more than 3 on the surface of nickel hydroxide particles. Since zinc or a zinc compound is added, the utilization factor of the active material is high and swelling hardly occurs.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is widely applicable to a paste type nickel electrode used as a positive electrode of an alkaline storage battery such as a nickel-cadmium storage battery or a nickel-hydrogen storage battery.

[0022]

EXAMPLES The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited to the following examples, and various modifications may be made without departing from the scope of the invention. Is possible.

(Example 1) [Preparation of powder composed of composite particles] Cobalt sulfate 13.
1 liter of an aqueous solution of 1 g, 100 parts of nickel hydroxide powder
g was added, and the pH of the solution was adjusted to 11 with a 1 M aqueous sodium hydroxide solution while stirring, and then stirring was continued for 1 hour. The pH at this time was monitored by a glass electrode pH meter with automatic temperature compensation. Next, the precipitate was filtered off, washed with water, and dried in vacuum to obtain a powder composed of composite particles obtained by coating the surfaces of nickel hydroxide particles with cobalt hydroxide. Since all the cobalt sulfate is deposited as cobalt hydroxide on the surface of the nickel hydroxide particles, the weight ratio of cobalt to nickel hydroxide particles in the coating layer is 5%.
Is. 1 part by weight of a powder composed of the composite particles was put into 10 parts by weight of a 25% by weight aqueous sodium hydroxide solution, heated in air at 80 ° C. for 30 minutes, and then washed with water,
After drying, an active material powder was prepared. When the average valence of cobalt in the cobalt compound after the heat treatment was determined by the method shown below, it was 2.7.

<How to obtain average valence of cobalt> A certain amount of a sample is weighed, dissolved in concentrated hydrochloric acid, and the amount of cobalt in the solution is quantified by an atomic absorption method. The amount of cobalt quantified at this time is the total amount of cobalt (total amount of divalent cobalt and trivalent cobalt) A contained in the coating layer. Next, the same amount of the same sample is separately weighed, dissolved in concentrated nitric acid, and the solution is filtered.
Since trivalent cobalt does not dissolve in nitric acid, a filtrate containing only divalent cobalt can be obtained by filtration. The amount of cobalt in this filtrate is quantified by an atomic absorption method. The amount of cobalt quantified at this time is the amount B of divalent cobalt contained in the coating layer. The average valence of cobalt of each sample is calculated by the following formula.

Average valence of cobalt = 3-B / A

[Preparation of Paste Type Nickel Electrode] 100 parts by weight of the above active material powder, 5.8 parts by weight of zinc oxide, and 1
A paste was prepared by kneading with 20 parts by weight of an aqueous solution of methyl cellulose (weight%), and the paste was filled into a porous body (substrate) made of nickel-plated foam metal (porosity 95%, average pore diameter 200 μm), dried, and molded. Then, a paste type nickel electrode was produced.

[Preparation of Alkaline Storage Battery] The above-mentioned paste type nickel electrode (positive electrode), a known paste type cadmium electrode (negative electrode) having a larger electrochemical capacity than the positive electrode, polyamide nonwoven fabric (separator), 30% by weight potassium hydroxide An AA size alkaline storage battery (battery capacity: about 700 mAh) A1 was produced using an aqueous solution (alkali electrolyte solution), a metal battery can, a metal battery lid, and the like.

(Comparative Example 1) In the same manner as in Example 1, an active material powder composed of composite particles obtained by coating the surface of nickel hydroxide particles with cobalt hydroxide was prepared. The weight ratio of cobalt to nickel hydroxide particles in the coating layer is 5
%. A paste is prepared by kneading 100 parts by weight of this active material powder and 20 parts by weight of a 1% by weight aqueous solution of methylcellulose, and the paste is made into a porous body made of nickel-plated foam metal (porosity 95%, average pore diameter 200 μm). The paste type nickel electrode was prepared by filling, drying and molding. Then, an AA size alkaline storage battery B1 was produced in the same manner as in Example 1 except that this paste nickel electrode was used as the positive electrode. Incidentally, the battery B1 is a conventional battery disclosed in Japanese Patent Laid-Open No. 62-234867.

Comparative Example 2 100 parts by weight of nickel hydroxide, 7.86 parts by weight of cobalt hydroxide and 20 parts by weight of a 1% by weight aqueous solution of methyl cellulose were kneaded to prepare a paste (water of cobalt in the paste). The weight ratio to nickel oxide is 5%), and this paste is nickel-plated foam metal (porosity 95%, average pore size 200μ)
m) was filled, dried and molded to prepare a paste-type nickel electrode, and then, in the same manner as in Example 1, an AA size alkaline storage battery B2 was manufactured. Incidentally, this battery B2 is a conventional battery disclosed in Japanese Patent Application Laid-Open No. 61-74261.

(Comparative Example 3) 100 parts by weight of nickel hydroxide, 7.86 parts by weight of cobalt hydroxide and 6.2 parts of zinc oxide.
Parts by weight and 20 parts by weight of a 1% by weight aqueous solution of methylcellulose are kneaded to prepare a paste (the weight ratio of cobalt to nickel hydroxide in the paste is 5%),
This paste was filled in a porous body made of nickel-plated foam metal (porosity 95%, average pore size 200 μm), dried and molded to prepare a paste-type nickel electrode, and then AA was performed in the same manner as in Example 1. A size alkaline storage battery B3 was produced. Incidentally, this battery B3 is a conventional battery disclosed in Japanese Patent Laid-Open No. 4-137368.

(Comparative Example 4) In the same manner as in Example 1, an active material powder composed of composite particles obtained by coating the surface of nickel hydroxide particles with cobalt hydroxide was prepared. The weight ratio of cobalt to nickel hydroxide particles in the coating layer is 5
%. 100 parts by weight of this active material powder, 5.8 parts by weight of zinc oxide, and 1% by weight aqueous solution of methylcellulose 20
A paste type nickel electrode is prepared by kneading parts by weight to prepare a paste, and filling the paste into a porous body made of nickel-plated foam metal (porosity 95%, average pore size 200 μm), drying and molding. It was made. Then, an AA size alkaline storage battery B4 was produced in the same manner as in Example 1 except that this paste nickel electrode was used as the positive electrode.

<Active material utilization rate and swelling rate of each paste-type nickel electrode> For each of the batteries prepared in Example 1 and Comparative Examples 1 to 4, after charging 160% at 0.1C at 25 ° C, 25 1 step to discharge to 1.0V at 1C at ° C
A cycle charge / discharge cycle test was performed to determine the 10th cycle active material utilization rate and the 10th cycle swelling rate of the paste nickel electrode used in each battery. The active material utilization rate was calculated based on the following formula.

Utilization rate of active material (%) = {discharge capacity at the 10th cycle (mAh) / (amount of nickel hydroxide (g) × 28)
8 (mAh / g)} × 100

The swelling ratio was calculated based on the following formula.

Swelling rate (%) = {(thickness of paste type nickel electrode after 10 cycles−thickness of paste type nickel electrode before charge / discharge cycle test) / thickness of paste type nickel electrode before charge / discharge cycle test} × 100

The results are shown in Table 1. The active material utilization rate and swelling rate of each paste-type nickel electrode in Table 1 are shown as indexes when the active material utilization rate and swelling rate of the paste-type nickel electrode used in Battery A1 are 100.

[0037]

[Table 1]

As shown in Table 1, the paste type nickel electrode of the battery A1 has a high active material utilization rate and a low expansion rate, whereas the paste type nickel electrodes of the batteries B1 to B4 have a low active material utilization rate. , The swelling rate is high. From this fact, in order to obtain a paste-type nickel electrode that has a high utilization rate of the active material and is difficult to swell, an active material obtained by coating the surface of nickel hydroxide particles with a cobalt compound having a cobalt valence of more than 2 It can be seen that it is necessary to use a powder to which a zinc compound is added. Although the zinc compound was used as the swelling inhibitor in Example 1, it was confirmed that the same effect can be obtained when metallic zinc is used. It was also confirmed that the same effect can be obtained when the coating layer is formed on the surface of the nickel hydroxide particles by the other method described above.

[Relationship Between Average Valence of Cobalt in Cobalt Compound and Utilization Rate of Active Material] The heat treatment time for forming the coating layer made of the cobalt compound on the surface of the nickel hydroxide particles was 5, 8, 12, 16 , 20, 25, 40, 48, 5
The average valence of cobalt was 2.1, 2.2, 2.3 in the same manner as in Example 1 except that the average valence was changed to 0 or 55 minutes.
2.4, 2.5, 2.6, 2.8, 2.93, 2.9
Forming a coating layer composed of 5 and 3 cobalt compounds, 1
0 kinds of active material powders were produced (the weight ratio of cobalt to nickel hydroxide particles in the coating layer was 5% in each case as in Example 1). Then, in the same manner as in Example 1, paste type nickel electrodes and AA size alkaline storage batteries A2 to A11 were produced.

A charge / discharge cycle test under the same conditions as above was carried out for each of the above batteries, and the active material utilization rate at the 10th cycle of the paste type nickel electrode used for each battery was determined.
The results are shown in Fig. 1. FIG. 1 shows the relationship between the average valence of cobalt in the cobalt compound and the utilization rate of the active material at the 10th cycle, the vertical axis represents the utilization rate of the active material, and the horizontal axis represents the average valence of cobalt. It is a graph. Note that FIG. 1 also shows the result of the battery A1 (heat treatment time 30 minutes; cobalt valence 2.7). The active material utilization rate on the vertical axis is an index when the active material utilization rate and the swelling rate of the paste nickel electrode used in Battery A1 are 100.

From FIG. 1, in order to obtain a paste type nickel electrode having a high utilization rate of the active material , the average valence of cobalt is 2.
It can be seen that it is necessary to coat the nickel hydroxide particles with a cobalt compound of 5-2.93.

[Relationship Between Weight Ratio of Cobalt to Nickel Hydroxide Particles in Active Layer and Utilization Rate of Active Material and Battery Capacity] The amount of cobalt sulfate used in forming the coating layer on the surface of nickel hydroxide particles was changed. The average valence of cobalt of the cobalt compound was 2. as in Example 1 except for the above.
7, the weight ratio of cobalt to nickel hydroxide particles in the coating layer was 0.5%, 1%, 5%, 10%, 15%,
Eight kinds of active material powders of 20%, 22.5% and 25% were prepared. Then, using each of these active material powders,
And the amount of zinc oxide added is 6.2 parts by weight,
Example 1 except 6.1 parts by weight, 5.8 parts by weight, 5.4 parts by weight, 5.0 parts by weight, 4.7 parts by weight, 4.6 parts by weight, 4.5 parts by weight Similarly to the above, a paste type nickel electrode and an AA size alkaline storage battery were produced.
The average valence of cobalt in the cobalt compound is 2.7.
And the weight ratio of zinc in zinc oxide to nickel hydroxide particles is 5% in all cases.

A charge / discharge cycle test was performed on each of the above batteries under the same conditions as above, and the utilization rate of the active material at the 10th cycle and the battery capacity at the 10th cycle of each battery were determined. The results are shown in Table 2. The active material utilization rate and the battery capacity in Table 2 are shown as an index when the active material utilization rate and the battery capacity of the battery (battery A1) in which the weight ratio of cobalt to nickel hydroxide particles is 5% are 100, respectively. There is.

[0044]

[Table 2]

From Table 2, in order to obtain a paste type nickel electrode having a high utilization rate of active material and a large capacity, the weight ratio of cobalt to nickel hydroxide particles in the coating layer is 1 to 20.
It turns out that it is preferable to set it as%.

[Relationship between Addition Amount of Zinc Compound and Swelling Rate and Battery Capacity] The addition amount of zinc oxide to the active material powder was 0.6 parts by weight, 1.2 parts by weight, and 100 parts by weight of the active material powder.
Parts by weight, 2.9 parts by weight, 5.8 parts by weight, 8.7 parts by weight,
A paste type nickel electrode and an AA size alkaline storage battery were produced in the same manner as in Example 1 except that the amounts were changed to 11.5 parts by weight, 13.9 parts by weight and 17.3 parts by weight. The weight ratio of zinc to zinc hydroxide particles in zinc oxide is 0.5%, 1%, 2.5%, 5%, 7.5%, in order.
10%, 12% and 15%. The average valence of cobalt in the cobalt compound is 2.7, and the weight ratio of cobalt to nickel hydroxide particles is 5%.

A charge / discharge cycle test was conducted on each of the above batteries under the same conditions as above, and the utilization rate of the active material at the 10th cycle and the battery capacity at the 10th cycle of each battery were determined. The results are shown in Table 3. The active material utilization rate and the battery capacity in Table 3 are shown as an index when the active material utilization rate and the battery capacity are 100 for a battery in which the weight ratio of zinc in zinc oxide to nickel hydroxide particles is 5%. is there.

[0048]

[Table 3]

From Table 3, in order to obtain a paste type nickel electrode having a high utilization rate of active material and a large capacity, the weight ratio of zinc in zinc oxide to nickel hydroxide particles is 1 to 10%.
It turns out that it is preferable to set

Although nickel hydroxide particles were used in the above-mentioned examples, the same applies to the case where solid solution particles in which cobalt, zinc, cadmium, calcium, manganese, magnesium, etc. are solid-dissolved in nickel hydroxide are used. It was confirmed that an excellent effect was obtained.

[0051]

The electrode of the present invention has a high utilization rate of the active material and is less likely to swell. Therefore, by using this as a positive electrode, it is possible to obtain an alkaline storage battery having a long charge / discharge cycle life.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the average valence of cobalt in a cobalt compound and the active material utilization rate.

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Reizou Maeda 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Mutsumi Yano 2-chome, Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd. (72) Inventor Kozo Nogami 2-5-5 Keihan Hondori, Moriguchi City, Osaka Prefecture Sanyo Electric Co., Ltd. (72) Inventor Ikuro Yonezu 2-5 Keihan Hondori, Moriguchi City, Osaka Prefecture No. 5 in Sanyo Electric Co., Ltd. (72) Inventor Koji Nishio 2-5-5 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd. (56) Reference JP-A-1-200555 (JP, A) Kaihei 4-160763 (JP, A) JP 5-21064 (JP, A) JP 6-283195 (JP, A) JP 7-73876 (JP, A) JP-B 2-59587 ( JP, B2) (58) Fields surveyed (In t.Cl. ⁷ , DB name) H01M 4/24-4/34 H01M 4/52 H01M 4/62

Claims (7)

(57) [Claims] 1. An active material powder composed of composite particles, wherein a coating layer composed of a cobalt compound having an average cobalt valence of 2.5 to 2.93 is formed on the surface of nickel hydroxide particles, and zinc is added to the active material powder. Alternatively, a paste-type nickel electrode for an alkaline storage battery, characterized in that a zinc compound is added. 2. The paste type nickel electrode for an alkaline storage battery according to claim 1, wherein the cobalt compound is a mixture of cobalt hydroxide and cobalt oxyhydroxide or cobalt oxyhydroxide. 3. The nickel hydroxide for cobalt in the coating layer.
The paste type nickel electrode for an alkaline storage battery according to claim 1 , wherein the weight ratio to the Kell particles is 1 to 20% . 4. Before zinc in the zinc or the zinc compound.
The weight ratio to the nickel hydroxide particles is 1 to 10%
Paste-type nickel electrode for an alkaline storage battery according to claim 1, wherein it is. 5. The active material powder is nickel hydroxide particles.
Cobalt hydroxide, cobalt monoxide and metal cobalt on the surface
A composite having a coating layer formed of at least one of
To the powder consisting of particles, add an alkaline aqueous solution and heat it.
The paste-type nickel electrode for an alkaline storage battery according to claim 1, which is obtained by cleaning, washing with water and drying . 6. The active material powder is nickel hydroxide powder.
Put in a cobalt salt aqueous solution, add an alkaline aqueous solution, and
The precipitate formed was filtered off, washed with water and dried to obtain hydroxy acid.
Coating layer made of cobalt hydroxide on the surface of nickel oxide particles
Alkaline aqueous solution is added to the powder composed of the composite particles
It is obtained by adding liquid, heat treatment, washing with water and drying.
Paste-type nickel electrode for alkaline storage battery of a claim 1, wherein. 7. The active material powder is nickel hydroxide powder.
And cobalt hydroxide powder, cobalt monoxide powder and metal
At least one kind of cobalt powder and an inert gas
Water obtained by dry mixing with a compression grinding mill in an atmosphere
Cobalt hydroxide, cobalt monoxide on the surface of nickel oxide particles
Coating layer containing at least one of cobalt and metallic cobalt
Alkaline aqueous solution is added to the powder composed of the composite particles
It is obtained by adding liquid, heat treatment, washing with water and drying.
Paste-type nickel electrode for alkaline storage battery of a claim 1, wherein.