JPH117951A - Nickel plate for alkaline storage battery and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nickel plate for an alkaline storage battery, capable of greatly suppressing a capacity reduction at high temperatures. SOLUTION: A nickel-sintered base material is dipped into nitric acid so as to have over its surface a layer of α-Ni(OH)2 . The base material is dipped into an aqueous solution of cobalt nitrate, then into an alkaline solution so as to have over the surface a layer of the solid solution of Ni and Co(OH)2 . The nickel-sintered base material is thereafter heated in atmosphere for oxidation so as to have over the surface a layer of the solid solution of Ni and Co3 O4 . Those procedures produce a nickel-sintered base. The obtained base is impregnated with an active material including Co.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nickel electrode (positive electrode) for an alkaline storage battery and a method for producing the same, and more particularly to an alkaline storage battery such as a nickel-cadmium storage battery using a nickel sintered substrate as a current collector. The present invention relates to a nickel electrode plate used and a method for manufacturing the same.

[0002]

2. Description of the Related Art In general, when an alkaline storage battery such as a nickel-cadmium storage battery is subjected to trickle charging at a high temperature, an oxygen overvoltage of a nickel electrode (positive electrode) is reduced, so that oxygen gas is easily generated and a discharge capacity is reduced. . Especially 50
Above ℃, the capacity is significantly reduced. Therefore, JP
JP-A-6-143669 discloses a technique in which a solid solution of cobalt and nickel hydroxide is present in an active material, and cadmium hydroxide is present on the surface of an electrode plate. Japanese Patent Application Laid-Open No. 57-23467 proposes adding cobalt trioxide (Co ₃ O ₄ ) to an active material.

Japanese Patent Application No. 3-314821 discloses a technique for forming a nickel-cobalt layer on the surface of a nickel sintered substrate by plating to maintain the conductivity of the surface of the nickel sintered substrate. Have been.

[0004]

However, in the technique of adding cobalt or a cobalt compound to an active material, a decrease in capacity at a high temperature cannot be largely suppressed.
This is because a corrosion layer mainly composed of nickel hydroxide is formed on the surface of the sintered substrate, and thus the conductivity of the surface of the sintered substrate is reduced.

Further, in order to form a nickel-cobalt layer on the surface of a nickel sintered substrate by plating, a large-scale apparatus is required, so that there has been a problem that the production of a nickel electrode plate becomes complicated.

An object of the present invention is to provide a nickel electrode plate for an alkaline storage battery and a method for manufacturing the same, which can greatly suppress a decrease in capacity at high temperatures.

An object of the present invention is to provide a method for easily producing a nickel electrode plate for an alkaline storage battery, which can greatly suppress a decrease in capacity at a high temperature.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a nickel electrode plate for an alkaline storage battery in which a current collector made of a nickel sintered substrate is filled with an active material. In the present invention, a layer of a solid solution of a metal other than cobalt and cobalt trioxide (Co ₃ O ₄ ) is formed on the surface of the nickel sintered substrate. Here, a metal other than cobalt and cobalt trioxide (Co)
The solid solution with ₃ O ₄ ) is a state in which some cobalt (Co) in Co ₃ O ₄ is replaced with a metal other than cobalt. The inventor has found that the surface of the nickel sintered substrate has Co
_It has been found that the formation of ₃ O ₄ can enhance the conductivity of the surface of the nickel sintered substrate. Further, it has been found that when a solid solution of a metal other than cobalt and cobalt trioxide (Co ₃ O ₄ ) is formed, the conductivity of the surface of the nickel sintered substrate can be further increased. This is considered to be because other metals having different ionic radii substitute for Co, so that the crystal structure is disordered and the specific surface area of the solid solution is increased. When the crystal structure is disordered in this manner, the oxygen overvoltage of the electrode plate decreases and the conductivity increases. Therefore, a decrease in the capacity of the battery at a high temperature can be greatly suppressed.

As metals other than cobalt, nickel,
Zinc, magnesium, cadmium, indium and the like can be used as examples.

The lattice constant of cobalt trioxide (Co ₃ O ₄ ) is 8.084 angstroms, but each of nickel, zinc, magnesium, cadmium, and indium forms a solid solution with cobalt trioxide. Then, the lattice constant increases. This is because other metals having different ionic radii substitute for Co, and the crystal structure is disordered. Therefore, when a solid solution is formed with these metals, the lattice constant of the solid solution is preferably 8.10 to 8.12 angstroms. If the amount of metals other than cobalt in the solid solution is small and the lattice constant is less than 8.10 angstroms, the conductivity of the substrate surface cannot be sufficiently increased. Even if the lattice constant exceeds 8.12 angstroms, the conductivity of the substrate surface decreases.

The present invention is preferably applied to an electrode plate in which the active material contains 30% by mole or more of Co hydroxide or Co oxide based on the whole active material. By doing so, the conductivity of the active material is also increased, and a decrease in capacity at high temperatures can be greatly suppressed.

To manufacture the nickel plate for an alkaline storage battery of the present invention, a nickel sintered substrate manufactured as follows is used. First, a nickel sintered substrate material is immersed in an aqueous nitric acid solution, and α-N
Form a layer of i (OH) ₂ . Next, the nickel sintered substrate material is immersed in an aqueous solution of cobalt nitrate and then immersed in an alkaline solution, so that the surface of the nickel sintered substrate material has Ni
And a layer of a solid solution of Co (OH) ₂ . Ni (O
Since H) ₂ and Co (OH) ₂ have similar crystal structures, a solid solution is easily formed. Next, the nickel sintered substrate material is oxidized, and Ni and Co are deposited on the surface of the nickel sintered substrate material.
A layer of solid solution with ₃ O ₄ is formed to make a nickel sintered substrate.

When the nickel electrode plate for an alkaline storage battery is manufactured in this manner, unlike the case where a nickel-cobalt layer is formed on the surface of a conventional nickel sintered substrate by plating, it can be easily performed without using a plating apparatus. Nickel plates can be manufactured.

Further, zinc nitrate [Zn] is used instead of the aqueous nitric acid solution.
If an aqueous solution containing a metal nitrate [M (NO ₃ )] such as (NO ₃ ) ₂ ] and nitric acid is used, a solid solution of Ni, M and Co ₃ O ₄ can be formed. In this case, since M preferentially forms a solid solution, the amount of Ni is considerably reduced.

Further, as a metal other than cobalt which forms a solid solution, an alkali metal can be used. When a solid solution is formed with an alkali metal and cobalt tetroxide, the lattice constant is reduced unlike the case where a metal such as nickel is used. This is because the lattice of the solid solution is distorted by the solid solution of the alkali metal. In addition, since the alkali metal has a lower valence than the nickel (monovalent), when the alkali metal is used, the solid solution layer has semiconductor properties.

As the alkali metal, lithium, sodium, potassium, rubidium, cesium and the like can be used. Among them, it is preferable to use lithium having the smallest ionic radius. This is because a metal having a larger difference in ionic radius from cobalt is more likely to have a disordered crystal structure when solidified with cobalt trioxide and the specific surface area of the solid solution is increased.

The proportion of the alkali metal in the solid solution layer is Co
_The content is preferably 10 to 30% based on the number of moles of cobalt in ₃ O ₄ . If it is less than 10%, the crystal structure is less disordered, and the specific surface area of the solid solution does not increase. 30%
When the ratio exceeds the above range, it is difficult to form a solid solution layer.

The solid solution layer desirably has a disordered crystal structure and low crystallinity. Therefore, the primary particle diameter calculated from the X-ray diffraction pattern is desirably 200 Å or less.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

(Example 1A) A nickel electrode plate for an alkaline storage battery of this example was manufactured as follows. First, a nickel sintered substrate material having a porosity of about 80% is immersed in a nitric acid solution having a pH of 1 at 70 ° C. for 2 minutes, so that about 0.5 μm thick α-Ni ( OH) ₂ layer was formed.
The thickness of the layer of α-Ni (OH) ₂ is preferably 0.3 to 1.0 μm. Next, this was immersed in a cobalt nitrate [Co (NO ₃ ) ₂ ] aqueous solution having a specific gravity of 1.3 (50 ° C.) at 60 ° C. for 10 minutes, and then immersed in a 20% by weight NaOH solution at 80 ° C. for 10 minutes. . As a result, a solid solution layer of Ni and Co (OH) ₂ was formed on the surface of the nickel sintered substrate material. In other words, the layer of α-Ni (OH) ₂ is
It was changed to a solid solution layer of i and Co (OH) ₂ . Next, the nickel sintered substrate material was heated in air at 200 ° C. for 1 hour to oxidize the surface of the nickel sintered substrate material. As a result, a solid solution layer of Ni and cobalt trioxide (Co ₃ O ₄ ) was formed on the surface of the nickel sintered substrate material to complete the nickel sintered substrate. The lattice constant of the solid solution formed on the surface was 8.102 angstroms.

Next, a series of active material impregnations in which the nickel sintered substrate is immersed in an aqueous solution (specific gravity: 1.6) of a mixture of nickel nitrate and cobalt nitrate having a molar ratio of Ni: Co of 70:30 and then subjected to alkali treatment. The operation was repeated several times to complete a nickel electrode plate.

(Example 1B) The nickel electrode plate for an alkaline storage battery of this example uses a nickel sintered substrate having a solid solution layer of Ni, Zn and Co ₃ O ₄ formed on the surface thereof.
Others were manufactured similarly to Example 1A. Specifically, instead of immersing the nickel sintered substrate material in a nitric acid solution, 0.5M zinc nitrate [Zn (NO ₃ ) ₂ ] and 70 ° C.
The nickel sintered substrate material was immersed in an aqueous solution containing nitric acid having a pH of 1 and the others were manufactured in the same manner as in Example 1A. Note that the solid solution formed on the surface has a lattice constant of 8.
It was 112 angstroms.

(Comparative Example 1A) A nickel electrode plate for an alkaline storage battery of this comparative example uses a nickel sintered substrate having a layer of only Co ₃ O ₄ formed on the surface thereof, and otherwise uses the same method as in Example 1A. Manufactured.

Specifically, the nickel sintered substrate material is immersed in a nitric acid solution, and the surface of the nickel sintered substrate material is coated with α.
Manufacturing was performed in the same manner as in Example 1A except that the step of forming a layer of —Ni (OH) ₂ was not performed. The lattice constant of the solid solution formed on the surface was 8.084 angstroms.

(Comparative Example 1B) The nickel electrode plate for an alkaline storage battery of the present comparative example uses a nickel sintered substrate material having nothing formed on the surface as it is as a nickel sintered substrate, and otherwise operates in the same manner as in Example 1A. Manufactured.

Example 2 The nickel electrode for an alkaline storage battery of this example has the same molar ratio of Co in the active material as about 10%, and the other parts are the same as those in Example 1A. Specifically, the active material impregnation operation was performed using an aqueous solution (specific gravity: 1.6) of a mixture of nickel nitrate and cobalt nitrate having a molar ratio of Ni: Co of 90:10, and the other conditions were the same as in Example 1A. Manufactured.

Comparative Example 2 A nickel electrode plate for an alkaline storage battery of this comparative example was manufactured in the same manner as in Example 2 except that the nickel sintered substrate material was used as a nickel sintered substrate.

Example 3 The nickel electrode for an alkaline storage battery of this example is an electrode having the same structure as that of Example 1A except that Co is not added to the active material. Specifically, the active material impregnation operation was performed using an aqueous solution of only nickel nitrate without using a mixture of nickel nitrate and cobalt nitrate, and the other operations were performed in the same manner as in Example 1A.

Comparative Example 3 A nickel electrode plate for an alkaline storage battery of this comparative example was manufactured in the same manner as in Example 3, except that the nickel sintered substrate material was used as a nickel sintered substrate.

Next, the above-mentioned nickel electrode plates and a known paste-type cadmium electrode plate (negative electrode plate) were wound via a PP separator to form an electrode plate group. Then, after disposing each electrode plate group in the battery can, an electrolytic solution composed of an aqueous solution of a mixture of NaOH and LiOH mixed at a weight ratio of 8: 2 is poured into the battery can, and the lid, the terminal, and the like are closed. 120 for mounting and testing
A sealed alkaline storage battery of 0 mAh was made. Then, a test was performed using each battery as follows.

First, each battery was held at a predetermined temperature for 2 hours, and then charged at 0.033 C for 24 hours to obtain a battery having a theoretical capacity of 150.
% Charged. Thereafter, each battery was discharged at 1C. The charging / discharging was performed by changing the ambient temperature from 20 ° C. to 70 ° C. to 55 ° C. to 45 ° C., and the change in the discharge capacity ratio with respect to each temperature when the discharge at 20 ° C. was set to 100 was examined. FIG. 1 shows the measurement results.

From this figure, it can be seen that the battery using the electrode plates of Examples 1A and 1B can suppress the decrease in the discharge capacity at a high temperature as compared with the battery using the electrode plates of Comparative Examples 1A and 1B.
Also, it can be seen that the batteries using the electrode plates of Examples 2 and 3 can suppress a decrease in the discharge capacity at high temperatures, respectively, as compared with the batteries using the electrode plates of Comparative Examples 2 and 3. Thus, when the amount of Co in the active material is the same, Ni and C
It can be seen that the use of a nickel sintered substrate formed with a layer of a solid solution with o ₃ O ₄ can suppress a decrease in discharge capacity at high temperatures.

Next, the time for immersing the nickel sintered substrate material having the α-Ni (OH) ₂ layer formed on the surface thereof in an aqueous solution of cobalt nitrate was adjusted to change the amount of Ni in the solid solution. A plurality of electrode plates having different lattice constants of the solid solution were prepared in the same manner as in 1A. Then, each electrode plate was discharged at 55 ° C. under the same conditions as above, and the relationship between the lattice constant and the discharge capacity was examined. FIG. 2 shows the measurement results. FIG. 2 shows that when the lattice constant of the solid solution is set to 8.10 to 8.12 angstroms, the discharge capacity at a high temperature can be maintained high.

Next, nickel plates for alkaline storage batteries of the following Examples and Comparative Examples were prepared and tested.

Example 11 A nickel electrode plate for an alkaline storage battery according to this example was manufactured as follows. First, a nickel sintered substrate material having a porosity of about 80% was mixed with a molar ratio of 10:90.
For 3 minutes in a mixed solution containing lithium nitrate and cobalt nitrate and having a specific gravity of 1.3 and a pH of 1 at 60 ° C., and about 0.5 μm thick Li and Co (NO ₃ ) A layer with 2H ₂ O was formed. The thickness of this layer is preferably from 0.3 to 0.7 μm. Then this is 70
After drying at 20 ° C. for 20 minutes, it was immersed in a 5 M lithium hydroxide aqueous solution at 100 ° C. for 20 minutes. Thus, a layer of a solid solution of Li and Co (OH) ₂ was formed on the surface of the nickel sintered substrate material. In other words, Li and Co
The layer of (NO ₃ ) .2H ₂ O was changed to a layer of a solid solution of Li and Co (OH) ₂ . Next, a current was passed through the nickel sintered substrate material at a current density of 3 mA / cm ² for 5 hours to oxidize the surface of the nickel sintered substrate material. Thus, a layer of a solid solution of Li and Co ₃ O ₄ was formed on the surface of the nickel sintered substrate material to complete the nickel sintered substrate.

Next, a series of active material impregnation operations in which the nickel sintered substrate was immersed in an aqueous solution of nickel nitrate (specific gravity: 1.6) and then subjected to alkali treatment was repeated a plurality of times to complete a nickel electrode plate.

Embodiment 12 A nickel electrode for an alkaline storage battery according to this embodiment uses a mixed solution of sodium nitrate and cobalt nitrate in a molar ratio of 10:90 instead of a mixed solution of lithium nitrate and cobalt nitrate, and uses a hydroxide solution. A 5M sodium hydroxide aqueous solution was used in place of the lithium aqueous solution, and the others were produced in the same manner as in Example 11. In the nickel electrode plate for an alkaline storage battery according to the present embodiment, a solid solution layer of Na and Co ₃ O ₄ is formed on the surface of a nickel sintered substrate material.

Embodiment 13 A nickel electrode for an alkaline storage battery of this embodiment uses a mixed solution of potassium nitrate and cobalt nitrate in a molar ratio of 10:90 instead of a mixed solution of lithium nitrate and cobalt nitrate, and uses lithium hydroxide. A 5M aqueous solution of potassium hydroxide was used in place of the aqueous solution, and the others were produced in the same manner as in Example 11. In the nickel electrode plate for an alkaline storage battery according to the present embodiment, a solid solution layer of K and Co ₃ O ₄ is formed on the surface of a nickel sintered substrate material.

(Comparative Example 11) In the nickel electrode plate for an alkaline storage battery of this comparative example, a layer in which Li was adsorbed on Co ₃ O ₄ was formed on the surface of the nickel sintered substrate material. The electrode plate of this comparative example was manufactured as follows. First, a nickel sintered substrate material having a porosity of about 80% is immersed in an aqueous solution containing cobalt nitrate at 60 ° C. and a specific gravity of 1.3 and pH = 1 for 3 minutes, and the thickness of the surface of the nickel sintered substrate material is reduced to about 80%. 0.5μ
An m layer of Co (NO ₃ ) .2H ₂ O was formed. The thickness of this layer is preferably from 0.3 to 0.7 μm. Then change this to 7
After drying at 0 ° C for 20 minutes, it was immersed in a 5M lithium hydroxide aqueous solution at 100 ° C for 20 minutes. Thus, a Co (OH) ₂ layer was formed on the surface of the nickel sintered substrate material. Next, a current was passed through the nickel sintered substrate material at a current density of 3 mA / cm ² for 5 hours to oxidize the surface of the nickel sintered substrate material. Thus, a Co ₃ O ₄ layer was formed on the surface of the nickel sintered substrate material. Next, this nickel sintered substrate material was immersed in a 5 M aqueous solution of lithium hydroxide at 100 ° C. for 1 hour to form a layer in which Li was adsorbed on Co ₃ O ₄ to complete a nickel sintered substrate.

Next, a series of active material impregnation operations in which the nickel sintered substrate was immersed in an aqueous solution of nickel nitrate (specific gravity 1.6) and then subjected to alkali treatment was repeated a plurality of times to complete a nickel electrode plate.

Comparative Example 12 In the nickel electrode for an alkaline storage battery of this comparative example, a layer made of only Co ₃ O ₄ is formed on the surface of the nickel sintered substrate material. The electrode plate of this comparative example was manufactured in the same manner as in Comparative Example 11 except that the step of immersing the nickel sintered substrate material having the Co ₃ O ₄ layer formed on the surface thereof in a lithium hydroxide aqueous solution was not performed. .

Comparative Example 13 In the nickel electrode for an alkaline storage battery of this comparative example, a Co ₃ O ₄ layer is formed on the surface of an active material layer filled in a nickel sintered substrate. The electrode plate of this comparative example was manufactured as follows. A series of active material impregnation operations in which a nickel sintered substrate material having no surface formed thereon is immersed in an aqueous solution of nickel nitrate (specific gravity 1.6) and then subjected to an alkali treatment are repeated a plurality of times to obtain a nickel sintered substrate material. An active material layer was formed. This was immersed in an aqueous solution of cobalt nitrate having a specific gravity of 1.3 and a pH of 1.0 at 60 ° C. Next, after drying this at 70 ° C. for 20 minutes,
Was immersed in a 5M aqueous solution of lithium hydroxide to produce cobalt hydroxide on the surface of the active material layer. Next, this was immersed in a lithium hydroxide aqueous solution for 20 minutes, and this was immersed in 3 mA / cm ^2.
At a current density of 5 hours to oxidize the cobalt hydroxide to produce Co ₃ O ₄ on the surface of the active material layer.

Next, each of the above-mentioned nickel electrode plates and a known paste-type cadmium electrode plate (negative electrode plate) were wound via a PP separator to form an electrode plate group. Then, after disposing each electrode plate group in the battery can, an electrolytic solution consisting of an aqueous solution of a mixture of NaOH and LiOH mixed at a weight ratio of 8: 2 is poured into the battery can, and the lid, terminals, and the like are closed. 120 for mounting and testing
A sealed alkaline storage battery of 0 mAh was made.

Table 1 shows the primary particle diameter of each of the above nickel plates, the amount (mol%) of alkali metal with respect to cobalt in the solid solution measured by atomic absorption, and the lattice constant of Co ₃ O ₄ calculated from the X-ray diffraction pattern. , And the oxygen overvoltage when the sealed alkaline storage battery using each nickel electrode plate is charged at 45 ° C. and 0.033 C. Note that Co ₃
Since O ₄ is cubic, the lattice constant indicates the value of the a-axis.

[0044]

[Table 1] Table 1 shows that, in the electrode plates of Examples 11 to 13 in which a solid solution was formed with an alkali metal and cobalt trioxide, unlike the case where a solid solution was formed with a metal such as nickel, the lattice constant of Co ₃ O ₄ (8 0.084), the lattice constant is reduced. In Examples 11 to 13 and Comparative Example 11, the primary particle diameter of the solid solution or Co ₃ O ₄ was 200 Å or less. This is considered to be because crystallinity was reduced due to the presence of the alkali metal. In the batteries using the electrode plates of Examples 11 to 13,
It can be seen that the oxygen overvoltage when charging at a high temperature (45 ° C.) is high due to the presence of the alkali metal, and the charging efficiency is improved.
In particular, in the battery using the electrode plate of Example 11 in which Li is fixed in volume, it can be seen that the oxygen overvoltage is higher. This is because Li ions increase crystal distortion.

Next, each battery was charged at 0.033 C at each temperature of 5 to 70 ° C., and then charged at 1 C (final voltage =
At a discharge of 1.1 V), the discharge capacity per 1 g of nickel hydroxide was measured, and the relationship between the temperature and the discharge capacity of each battery was examined. FIG. 3 shows the measurement results. 3, the batteries using the electrode plates of Examples 11 to 13 were compared with Comparative Examples 11 to 13.
It can be seen that the discharge capacity is larger than that of the battery using the electrode plate. The discharge capacity has a correlation with the oxygen overvoltage. The higher the oxygen overvoltage, the larger the discharge capacity at a high temperature, and the lower the oxygen overvoltage, the smaller the discharge capacity at a high temperature.

Next, the molar ratio of alkali metal (Li) to cobalt in the solid solution was varied by changing the mixing ratio of the mixed solution of lithium nitrate and cobalt nitrate. ) I made different quantity of plates. Then, the primary particle diameter of the solid solution of each electrode plate was measured, and the relationship between the amount of alkali metal (Li) and the primary particle diameter of the solid solution was examined. FIG. 4 shows the measurement results. According to FIG. 4, when the amount of alkali metal (Li) increases,
It can be seen that the primary particle size becomes smaller. This is because when the amount of the alkali metal (Li) increases, the crystal distortion increases, and the crystallinity decreases.

Next, batteries were prepared using the electrode plates having different amounts of alkali metal (Li) produced in the same manner as described above, and the discharge capacities of each battery discharged at 45 ° C. and 70 ° C. were measured. The relationship between the amount of metal (Li) and the discharge capacity was examined. The measurement of the discharge capacity was performed under the same conditions as in the test shown in FIG. FIG. 5 shows the measurement results. According to FIG. 5, the amount of alkali metal (Li) with respect to cobalt is 10 to 3
It can be seen that when the content is 0 mol%, the discharge capacity increases. When the amount of the alkali metal (Li) is less than 10 mol%, the distortion of the crystal is reduced and the discharge capacity cannot be increased. On the other hand, when the amount of the alkali metal (Li) exceeds 30 mol%, the filling amount of the active material decreases, and the discharge capacity cannot be increased.

Next, the drying temperature after immersing the sintered substrate in cobalt nitrate was changed to change variously the diameter of the primary particles of the solid solution calculated from the X-ray diffraction pattern. Electrodes having different particle sizes were made. When the drying temperature is low, the primary particle size is small, and when the drying temperature is high, the primary particle size is large. Then, the discharge capacity when each battery was discharged at 45 ° C. and 70 ° C. was measured, and the relationship between the primary particle diameter and the discharge capacity at each temperature was examined. The measurement of the discharge capacity was performed under the same conditions as in the test shown in FIG. FIG. 6 shows the measurement results. FIG. 6 shows that when the primary particle diameter is 200 Å or less, the discharge capacity increases. The primary particle diameter has a correlation with the amount of alkali metal (Li) shown in FIG. Alkali metal (L
i) When the amount is small, the crystallinity of the solid solution is high and the primary particle diameter is large, and when the amount of alkali metal (Li) is large, the crystallinity of the solid solution is low and the primary particle diameter is small.

[0049]

The solid solution of a metal other than cobalt and cobalt trioxide (Co ₃ O ₄ ) is considered to have a disordered crystal structure because other metals having different ionic radii substitute for Co. According to the present invention, since such a solid solution is formed on the surface of the sintered substrate, the conductivity of the surface of the nickel sintered substrate can be greatly increased, and a decrease in capacity at high temperatures can be greatly suppressed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between an ambient temperature and a discharge capacity ratio of each battery used in a test.

FIG. 2 is a diagram showing a relationship between a lattice constant of a solid solution and a discharge capacity at a high temperature.

FIG. 3 is a diagram showing the relationship between the temperature and the discharge capacity of each battery used in the test.

FIG. 4 is a graph showing the relationship between the amount of alkali metal (Li) and the primary particle size of a solid solution.

FIG. 5 is a diagram showing the relationship between the amount of alkali metal (Li) and discharge capacity.

FIG. 6 is a diagram showing a relationship between a primary particle diameter and a discharge capacity at each temperature.

Claims (10)

[Claims] 1. A nickel electrode for an alkaline storage battery in which a current collector made of a nickel sintered substrate is filled with an active material, wherein a metal other than cobalt and C
A nickel electrode plate for an alkaline storage battery, wherein a solid solution layer with o ₃ O ₄ is formed. 2. The nickel plate for an alkaline storage battery according to claim 1, wherein the metal other than cobalt is nickel. 3. The solid solution has a lattice constant of 8.10 to 10.10.
3. The nickel plate for an alkaline storage battery according to claim 2, wherein the nickel plate is 8.12 angstroms. 4. The active material includes Co hydroxide or C hydroxide.
The nickel electrode plate for an alkaline storage battery according to claim 2, wherein the o-oxide is contained in an amount of 30 mol% or more based on the whole of the active material. 5. The nickel plate for an alkaline storage battery according to claim 1, wherein the metal other than cobalt is an alkali metal. 6. The method according to claim 5, wherein the alkali metal is lithium, sodium, or potassium.
4. A nickel electrode plate for an alkaline storage battery according to claim 1. 7. The ratio of the alkali metal in the solid solution layer is 10 to the number of moles of cobalt in the Co ₃ O _4.
The nickel electrode plate for an alkaline storage battery according to claim 5, wherein the content is about 30%. 8. The nickel electrode plate for an alkaline storage battery according to claim 5, wherein the solid solution layer has a primary particle diameter calculated from an X-ray diffraction pattern of 200 Å or less. 9. A method for manufacturing a nickel electrode plate for an alkaline storage battery by filling a current collector formed of a nickel sintered substrate with an active material, wherein the nickel sintered substrate is prepared by disposing a nickel sintered substrate material in a nitric acid aqueous solution. Dipping to form a layer of α-Ni (OH) _{2 on} the surface of the nickel sintered substrate material, and then dipping the nickel sintered substrate material in an aqueous solution of cobalt nitrate and then in an alkaline solution Forming a solid solution layer of Ni and Co (OH) _{2 on} the surface of the nickel sintered substrate material; and oxidizing the nickel sintered substrate material to form a surface portion of the nickel sintered substrate material. And forming a layer of a solid solution of Ni and Co ₃ O ₄ on the substrate. 10. A method for manufacturing a nickel electrode for an alkaline storage battery by filling a current collector formed of a nickel sintered substrate with an active material, wherein the nickel sintered substrate is made of a metal nitrate [M (NO ₃ )] ₂ (M is a metal) and an aqueous solution containing nitric acid to form a layer of α-Ni (OH) ₂ and M (OH) _{2 on} the surface of the nickel sintered substrate material Next, the nickel sintered substrate material is immersed in an aqueous solution of cobalt nitrate and then immersed in an alkaline solution to form a solid solution of Ni, M and Co (OH) _{2 on} the surface of the nickel sintered substrate material. Forming a layer and then oxidizing the nickel sintered substrate material to form a solid solution layer of Ni, M and Co ₃ O _{4 on} the surface of the nickel sintered substrate material. Of producing nickel plates for alkaline storage batteries.