JP2001043856A - Non-sintered nickel electrode for alkali storage battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance active material utilization factor of charge/discharge cycle over a long period of time by using a positive electrode active material prepared by containing at least one of copper, tin, magnesium, zinc, and cadmi um in the form of a solid solution in α-nickel hydroxide containing a specified ratio of manganese to the sum of manganese and nickel in the form of a solid solution. SOLUTION: γ-NiOOH of the charge product of α-nickel hydroxide containing 15-50 wt.% manganese to the sum of manganese and nickel in the form of a solid solution has high oxygen overvoltage, high charging accept capability, and relative decrease in the amount of the nickel hydroxide acting as an active material is suppressed. At least one Cu, Sn, Mg, Zn, and Cd contained in the form of a solid solution suppresses excess formation of γ-NiOOH, prevents dry up caused by exhaustion of an electrolyte, and the content is preferable to be limited to 0.5-5 wt.% to the sum of Ni and Mn. Hydroxide, monoxide, or sodium-containing compound of cobalt of 2-15 wt.% calculated in terms of element to the nickel hydroxide is preferable to be added or to cover it as a conductor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-sintered nickel electrode used as a positive electrode of an alkaline storage battery.

[0002]

2. Description of the Related Art
Perforated steel plate with perforated nickel powder as the positive electrode for nickel-metal hydride batteries and nickel-cadmium batteries
Sintered nickel electrodes obtained by impregnating a sintered substrate obtained by sintering an active material (nickel hydroxide) with a sintered substrate are well known.

In order to increase the amount of active material to be filled in a sintered nickel electrode, it is necessary to use a sintered substrate having high porosity. However, since the bond between the nickel particles due to sintering is weak, if the porosity of the sintered substrate is increased, the nickel particles are likely to fall off the sintered substrate. Therefore, in practice, the porosity of the sintered substrate cannot be made larger than 80%, and therefore, the sintered nickel electrode has a problem that the active material filling amount is small. In addition, since the pore size of the sintered body of nickel powder is generally as small as 10 μm or less, the filling of the active material into the sintered substrate must be performed by a solution impregnation method in which a complicated impregnation step needs to be repeated several times. There is also a problem.

[0004] Under such circumstances, a non-sintered nickel electrode has recently been proposed. The non-sintered nickel electrode is manufactured by filling a kneaded product (paste) of an active material (nickel hydroxide) and a binder (aqueous methylcellulose solution) into a substrate having a porosity of 95% or more such as a foamed nickel substrate. be able to. Since a substrate with high porosity can be used, the amount of the active material to be filled can be increased, and the active material can be easily filled into the substrate.

However, if a nonporous nickel electrode is used to increase the amount of the active material to be filled, the use of a substrate having a higher porosity will lower the current collecting capability of the substrate and lower the active material utilization.

Therefore, as an active material capable of increasing the utilization rate of the active material of the non-sintered nickel electrode, at least one of manganese, cadmium, calcium, magnesium, iron and cobalt is obtained in an amount of 1 to 7% by weight. Dissolved active material (JP-A-5-21064) and nickel hydroxide containing trivalent manganese (JP-A-7-335214)
No. 1). However, in these methods, although the initial utilization rate of the positive electrode active material is improved, γ-NiOOH is generated at the end of the charge / discharge cycle, and water is taken into the crystals of the active material, so that the electrolyte is depleted. However, there has been a problem that the internal resistance of the battery rises and the utilization rate of the active material drops sharply.

An object of the present invention is to provide a non-sintered nickel electrode for an alkaline storage battery capable of obtaining a high active material utilization rate over a long charge / discharge cycle.

[0008]

SUMMARY OF THE INVENTION The non-sintered nickel electrode of the present invention is composed of α-type nickel hydroxide in which manganese is solid-dissolved in an amount of 15 to 50% by weight based on the total amount of nickel and manganese;
It is characterized in that a solid solution of at least one element selected from tin, magnesium, zinc and cadmium is used as a positive electrode active material.

In the present invention, α is a solid solution of manganese.
Type nickel hydroxide is used. By using such α-type nickel hydroxide (α-Ni (OH) ₂ ),
Γ-type nickel oxyhydroxide (γ-NiO
OH) is increased, and γ-NiOOH has a high oxygen overvoltage, so that charge acceptability is improved. In the present invention, the solid solution amount of manganese is set to 15 to 50% by weight based on the total amount of nickel and manganese. When the solid solution amount of manganese is less than 15% by weight, the improvement in charge acceptability is insufficient, so that a sufficient active material utilization rate cannot be obtained. If the solid solution amount of manganese exceeds 50% by weight, the amount of nickel hydroxide as an active material is relatively reduced, so that a sufficient battery capacity cannot be obtained.

The solid solution amount of manganese is defined by the following equation. Solid solution amount of manganese (% by weight) = (weight of manganese in nickel hydroxide) / (total weight of nickel and manganese in nickel hydroxide) As described above, in the present invention, α -Type nickel hydroxide is used as a positive electrode active material, and the amount of γ-NiOOH in the charge product is increased, so that the charge acceptability is improved. However, if the amount of γ-NiOOH is too large, this crystal The water in the electrolyte is taken into the electrolyte, so that the so-called dry-out of the electrolyte occurs, the internal resistance of the battery increases, and the utilization rate of the active material decreases rapidly. Therefore, in the present invention, copper, tin, magnesium,
At least one element selected from zinc and cadmium is dissolved as a solid solution, thereby suppressing the production of γ-NiOOH.

In the present invention, the solid solution amount of at least one element selected from copper, tin, magnesium, zinc and cadmium is 0.5 to 5% by weight based on the total amount of the element, nickel and manganese. Is preferred. When the solid solution amount of an element such as copper is less than 0.5% by weight, γ-NiO
In some cases, the generation of OH cannot be sufficiently suppressed. On the other hand, when the content exceeds 5% by weight, the amount of nickel hydroxide as an active material is relatively reduced, and the battery capacity may be reduced. The solid solution amount of an element such as copper is defined by the following equation.

Solid solution amount of element such as copper (% by weight) = (weight of element such as copper in nickel hydroxide) / (total weight of element such as copper, nickel and manganese in nickel hydroxide) In addition, 2 to 15% by weight of cobalt hydroxide, cobalt monoxide, or a sodium-containing cobalt compound in terms of cobalt element based on the total amount of nickel hydroxide is added to nickel hydroxide or coated with nickel hydroxide. Is preferred. The cobalt amount in terms of the cobalt element is defined by the following equation.

Amount of cobalt (% by weight) = (weight of cobalt element in cobalt compound) / (weight of nickel hydroxide in which elements such as manganese and copper are dissolved) If the amount of cobalt is less than 2% by weight, conductivity Since the amount of cobalt that functions as an agent is small, the obtained battery capacity may decrease. On the other hand, when the content exceeds 15% by weight, the filling amount of nickel hydroxide, which is an active material, relatively decreases, so that the battery capacity may decrease.

When nickel hydroxide is coated with a cobalt hydroxide layer, the cobalt hydroxide layer is formed, for example, by adding nickel hydroxide to a cobalt salt aqueous solution (such as an aqueous solution of cobalt sulfate) and stirring the mixture with an alkaline aqueous solution (sodium hydroxide). (Aqueous solution, etc.) to drop the pH to about 11, and then react for a predetermined period of time while stirring to precipitate cobalt hydroxide on the surface of the nickel hydroxide particles. Since the alkali is consumed during the reaction and the pH is lowered, it is necessary to prevent the pH from lowering by appropriately adding an aqueous alkali solution.

Further, the cobalt monoxide layer or the cobalt hydroxide layer is formed by mechanically mixing a nickel hydroxide powder and a cobalt monoxide powder or a cobalt hydroxide powder in an inert gas atmosphere by a dry milling / pulverizing machine. It can also be formed by a charge method.

The coating layer comprising a sodium-containing cobalt compound can be formed by reacting a cobalt layer such as the above-mentioned cobalt monoxide layer or cobalt hydroxide layer with an aqueous sodium hydroxide solution. However, the coating layer composed of the sodium-containing cobalt compound is not formed only by adding sodium hydroxide to the powder composed of the composite particles on which the cobalt layer has been formed, and requires a heat treatment. The heating temperature is preferably about 50 to 200 ° C. When the heating temperature is lower than 50 ° C., CoHO ₂ having low conductivity is used.
May be deposited and a coating layer having good conductivity may not be formed. If the heating temperature exceeds 200 ° C., tricobalt tetroxide (Co ₃ O ₄ ) having low conductivity may precipitate, and a coating layer having good conductivity may not be formed. When the cobalt layer is a cobalt oxyhydroxide layer, CoHO ₂ does not precipitate even if heated at a temperature of less than 50 ° C., but it is difficult for sodium to be inserted. The heat treatment time differs depending on the amount and concentration of the aqueous sodium hydroxide used, the heat treatment temperature, and the like. Generally, 0.5 to 10
About an hour.

Specific examples of the sodium-containing cobalt compound forming the coating layer include sodium-containing cobalt hydroxide, sodium-containing cobalt oxyhydroxide, and a mixture thereof. The chemical structure of the sodium-containing cobalt compound is not yet clear to the present inventors, but since it has an extremely high electrical conductivity, it is not a mere mixture of the cobalt compound and sodium,
It is presumed that it is an intercalation compound having a structure in which sodium is inserted into the crystal of the cobalt compound.

The amount of cobalt hydroxide or the like added or coated is preferably 2 to 15% by weight as described above. 2% by weight
If it is less than 30, the conductivity of the active material particles cannot be increased, so that a sufficient active material utilization rate may not be obtained. If it exceeds 15% by weight, the amount of nickel hydroxide, which is an active material, becomes relatively small, so that a sufficient battery capacity may not be obtained.

Examples of the non-sintered nickel electrode of the present invention include a paste-type nickel electrode obtained by applying a paste containing the above active material to a conductive core and drying the paste. Specific examples of the conductive core at this time include a nickel foam, a felt-like porous metal fiber, and a punching metal. Furthermore, a tubular nickel electrode for filling the active material into the tubular metal conductor, a pocket nickel electrode for filling the active material into the pocket-shaped metal conductor, and the active material pressed together with the mesh-shaped metal conductor The present invention can also be applied to a molded nickel electrode for a button type battery.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in more detail with reference to examples. However, the present invention is not limited to the following examples, and may be appropriately modified within the scope of the invention. It can be implemented by

(Preliminary experiment) Cobalt hydroxide and a 25% by weight aqueous solution of sodium hydroxide were mixed at a weight ratio of 1:10, heated at 90 ° C. for 5 hours, washed with water, and washed at 60 ° C. To produce a sodium-containing cobalt compound. The sodium content of the prepared sodium-containing cobalt compound was determined by an atomic absorption method.
% By weight.

(Experiment 1) Here, batteries A1 to A10 using an active material in which manganese and at least one selected from copper, tin, zinc, magnesium and cadmium were dissolved in nickel hydroxide, only manganese was dissolved. The active material utilization of the comparative battery X using the active material and the comparative battery Y using the active material in which trivalent manganese was dissolved was measured at the third cycle and the 50th cycle.

[0023] (Example 1-1) Preparation of Positive Electrode Step 1: manganese sulfate _{(MnSO 4 · 5H 2 O)} 8
7.8 g, nickel sulfate _{(NiSO 4 · 7H 2 O)} 38
2.8 g, to 5000ml prepared aqueous solution of copper sulfate (CuSO ₄₎ 12.2g. To this, a mixed aqueous solution of 10% by weight of ammonia and 10% by weight of sodium hydroxide was added dropwise to maintain the pH at 9.5 ± 0.3. When the pH drops, the mixed aqueous solution is dropped and the pH becomes constant.
Mix for hours. After mixing, the mixture was filtered, washed with water, and dried at 80 ° C. At this time, 20% by weight of manganese was dissolved in the total amount of nickel and manganese in nickel hydroxide,
It was confirmed by atomic absorption spectroscopy that copper was dissolved in 3% by weight of the total amount of nickel, manganese and copper.

Step 2: One liter of an aqueous solution in which 13.2 g of cobalt sulfate is dissolved is mixed with 100 parts of the above nickel hydroxide.
g of the solution, and a 1 mol / liter aqueous sodium hydroxide solution was added thereto while stirring to adjust the pH of the solution to 11.
The reaction was continued while stirring for hours. When the pH of the solution dropped slightly, a 1 mol / liter aqueous solution of sodium hydroxide was appropriately added dropwise to maintain the pH of the solution at 11. Then
The precipitate was separated by filtration, washed with water, and dried under vacuum to form a coating layer made of cobalt hydroxide on the surface of the nickel hydroxide particles.
The amount of cobalt at this time is 5% by weight based on nickel hydroxide in which manganese and copper are dissolved.

Step 3: The above powder and a 25% by weight aqueous sodium hydroxide solution are mixed at a weight ratio of 1:10, and
After heat treatment at 0 ° C. for 5 hours, it was washed with water and dried at 65 ° C. to prepare an active material powder composed of composite particles having a coating layer made of a sodium-containing cobalt compound formed on the surface of nickel hydroxide particles. From the results of the preliminary experiment, it is estimated that the sodium content of the sodium-containing cobalt compound forming the coating layer is 1% by weight.

[Preparation of Non-Sintered Nickel Electrode] 90 parts by weight of nickel hydroxide having a surface containing a sodium-containing cobalt compound and solid solution of manganese and copper and 20 parts by weight of a 1% by weight aqueous methylcellulose solution as a binder And kneading the mixture to prepare a paste, filling this paste into a porous substrate made of nickel-plated foam metal (porosity 95%, average pore diameter 200 μm), drying, and press-forming.
An electrode a of the present invention was produced.

[Preparation of Alkaline Storage Battery] Using the electrode a of the present invention obtained as described above as a positive electrode, an AA-size positive electrode-dominated alkaline storage battery (battery capacity 1000 mA)
h) was prepared. A conventionally known paste-type cadmium electrode having a larger electrochemical capacity than the positive electrode was used as the negative electrode, a polyamide nonwoven fabric was used as the separator, and a 30% by weight aqueous solution of potassium hydroxide was used as the electrolytic solution.

FIG. 1 is a schematic sectional view showing an alkaline storage battery assembled using the above constituent materials. As shown in FIG. 1, the alkaline storage battery includes a positive electrode 1, a negative electrode 2, a separator 3, a positive electrode lead 4, a negative electrode lead 5, a positive electrode external terminal 6, a negative electrode can 7, a sealing lid 8, and the like. The positive electrode 1 and the negative electrode 2 are housed in a negative electrode can 7 in a state of being spirally wound via a separator 3. Positive electrode 1
Is connected to the sealing lid 8 via the positive electrode lead 4,
The negative electrode 2 is connected to a negative electrode can 7 via a negative electrode lead 5. An insulating packing 10 is attached to the connection between the negative electrode can 7 and the sealing lid 8.
0 seals the battery. A coil spring 9 is provided between the positive electrode external terminal 6 and the sealing lid 8 so that when the battery internal pressure rises abnormally, the battery is compressed and the gas inside the battery can be released to the atmosphere. I have.

(Example 1-2) Instead of 87.8 g of manganese sulfate and 382.8 g of nickel sulfate of Example 1-1,
Battery A2 was obtained in the same manner as in Example 1-1, except that manganese sulfate was 35.1 g and nickel sulfate was 440.2 g. Here, it was confirmed by an atomic absorption method that the solid solution amount of manganese was 8% by weight based on the total amount of nickel and manganese.

(Example 1-3) In place of 87.8 g of manganese sulfate and 382.8 g of nickel sulfate in Example 1-1,
Battery A3 was obtained in the same manner as in Example 1-1, except that manganese sulfate was 65.8 g and nickel sulfate was 406.7 g. Here, it was confirmed by an atomic absorption method that the solid solution amount of manganese was 15% by weight based on the total amount of nickel and manganese.

(Example 1-4) In place of 87.8 g of manganese sulfate and 382.8 g of nickel sulfate of Example 1-1,
219.4 g of manganese sulfate, 239.3 g of nickel sulfate
A battery A4 was obtained in the same manner as in Example 1-1, except that Here, it was confirmed by an atomic absorption method that the solid solution amount of manganese was 50% by weight based on the total amount of nickel and manganese.

(Example 1-5) In place of 87.8 g of manganese sulfate and 382.8 g of nickel sulfate in Example 1-1,
241.4 g of manganese sulfate, 215.3 g of nickel sulfate
A battery A5 was obtained in the same manner as in Example 1-1, except that Here, it was confirmed by an atomic absorption method that the solid solution amount of manganese was 55% by weight based on the total amount of nickel and manganese.

(Example 1-6) The copper sulfate of Example 1-1 was used.
Instead, tin sulfate (SnSO4)_Four) 5.60g, sulfated mug
Nesium (MgSO_Four・ 7H_TwoO) 31.4 g, sulfite
Lead (ZnSO_Four・ 7H _TwoO) 13.6 g, cadmium sulfate
(CdSO_FourExample 1 except that 5.74 g was used.
In the same manner as in -1, batteries A6 to A9 were obtained. Where tin,
The solid solution amounts of magnesium and zinc are nickel and man, respectively.
It should be 3% by weight based on the sum of the gun and solid solution elements.
It was confirmed by the secondary absorption method.

(Example 1-7) The procedure of Example 1-1 was repeated, except that the mixture of 6.1 g of copper sulfate and 6.8 g of zinc sulfate was used instead of the copper sulfate of Example 1-1. Battery A10
I got Here, it was confirmed by atomic absorption spectroscopy that the solid solution amounts of copper and zinc were 1.5% by weight based on the total amount of nickel, manganese and the solid solution elements, respectively.

Comparative Example 1 A battery X was produced in the same manner as in Example 1-1, except that copper sulfate was not added in Step 1 of Example 1-1. At this time, it was confirmed by an atomic absorption method that the solid solution amount of manganese was 20% by weight based on the total amount of nickel and manganese.

(Comparative Example 2) Manganese nitrate (tetrahydrate) 1
0.04 g, nickel nitrate (hexahydrate) 58.16 g,
12.5 g of sulfuric acid (97% by weight), 1 of acetic acid (99% by weight)
Water was added to a mixed solution of 0.00g and 10.00g of phosphoric acid (85% by weight) until the volume became 250ml (solution A). 1.58 g of potassium permanganate, sulfuric acid (97% by weight) 1
Water was added to a mixed solution of 2.5 g, 10.00 g of acetic acid (99% by weight), and 10.00 g of phosphoric acid (85% by weight) until the volume reached 250 ml (solution B). These solutions A and B were
The mixture was injected at a rate of 0 ml / hour into a 2 liter beaker and reacted. Then, this solution was dropped into 1 liter of an aqueous solution of potassium hydroxide maintained at pH = 12.5. After charging the whole amount, the mixture was mixed for 1 hour and aged for 15 hours. Then, the precipitate is filtered, and 650 ml of an aqueous potassium hydroxide solution (p
H = 12.5) for 5 times, and then in vacuum at 51 ° C. for 3 times.
Let dry for days. At this time, it was confirmed by an atomic absorption method that the solid solution amount of manganese was 20% by weight based on the total amount of nickel and manganese.

A paste prepared by mixing 90 g of this powder and 10 g of cobalt hydroxide with 50 g of a 1% by weight aqueous solution of methylcellulose was prepared, and this paste was nickel-plated into a foam metal (porosity 95%, average An electrode was prepared by filling a porous substrate having a pore size of 200 μm), drying and pressing. Battery Y was produced in the same manner except that this was used for the positive electrode.

(Active Material Utilization of Non-Sintered Nickel Electrode) The batteries prepared in Examples 1-1 to 1-7 and Comparative Examples 1 and 2 were tested at 25 ° C. at a current of 100 mA. After charging for 16 hours, at 25
A charge / discharge cycle test was performed in which the process of discharging to V was one cycle, and the non-sintered nickel electrode 3 used for each battery was tested.
The active material utilization rates at the 50th cycle and the 50th cycle were examined.
The active material utilization was calculated based on the following equation.

Active material utilization rate (%) = ｛discharge capacity (mA)
h) / [amount of nickel hydroxide in active material (g) × 288
(MAh / g)]｝ × 100 The results are shown in Table 1. The numerical values are indicated by an index with the active material utilization rate in the third cycle of the A1 battery being 100.

[0040]

[Table 1]

As is clear from the results shown in Table 1, the active material was prepared by dissolving at least one of copper, tin, magnesium, zinc, and cadmium in nickel hydroxide powder in which manganese was solid-solved at 15 to 50% by weight. Battery A used as
It can be seen that 1, A3 to A4 and A6 to A10 can obtain a high active material utilization rate over a long period of the charge / discharge cycle.

(Relationship Between Manganese Solid Solution and γ-NiOOH Generation Rate) After charging / discharging three cycles, each battery was charged at 25 ° C. at 100 mA for 24 hours, and then the positive electrode active material was taken out of the battery. A line diffraction measurement was performed. Attributable to γ-NiOOH among the obtained diffraction lines (003)
The production rate of γ-NiOOH was determined from the peak intensities of the plane and the (001) plane attributed to β-NiOOH. γ-N
The generation rate of iOOH is defined by the following equation.

Γ-NiOOH generation rate (%) = (003)
Plane peak intensity / ((003) plane peak intensity + (001)
FIG. 1 shows the obtained results. Note that the production rate of γ-NiOOH of each battery in FIG.
Is a relative value when the generation rate is 100.

As is clear from the results shown in FIG. 1, when the manganese solid solution amount is 15% by weight or more, γ-Ni
It is stable in a range where the generation rate of OOH is high. Further, in the present invention, γ-NiOOH
Is suppressed, but as an alternative method, a method of reducing the solid solution amount of manganese can be considered. However, as is evident from the results shown in FIG. 1, when the amount of solid solution of manganese is reduced, the generation rate of γ-NiOOH changes rapidly. Therefore, it is necessary to suppress the generation rate of γ-NiOOH within a stable range. Becomes difficult.

(Experiment 2) In this experiment, the amount of copper dissolved in nickel hydroxide in which manganese was dissolved was examined.

(Example 2-1) Copper sulfate 1 of Example 1-1
0.39 g, 1.97 g, 20.7 instead of 2.2 g
g, 29.6 g, and batteries B1 to B4 were produced in the same manner as in Example 1-1. At this time, the solid solution amount of copper was quantified by an atomic absorption method, and as a result, 0.1, 0.5, 5, and 7 were determined based on the total amount of nickel, manganese, and copper, respectively.
% By weight. The same tests as in Example 1-1 were performed on the obtained batteries B1 to B4. Table 2 shows the results. Table 2 also shows the results of the battery A1, and the active material utilization is a relative value with the active material utilization of the battery A1 being 100.

[0047]

[Table 2]

As is evident from the results shown in Table 2, in order to obtain an alkaline storage battery having a high active material utilization rate not only in the initial period but also in a long charge / discharge cycle, the amount of the copper element dissolved in the solid solution must be as follows. It is understood that the content is preferably 0.5 to 5% by weight based on the total amount of nickel, manganese and copper.

(Relationship between the amount of solid solution of copper element and the yield of γ-NiOOH) After charging / discharging each battery after 3 cycles of charging and discharging at 25 ° C. and 100 mA for 24 hours, the positive electrode active material was taken out of the battery, and the powder X A line diffraction measurement was performed. From the peak intensities of the (003) plane attributed to γ-NiOOH and the (001) plane attributed to β-NiOOH, the yield of γ-NiOOH was determined in the same manner as described above. .

FIG. 2 shows the obtained results. In addition, similarly to the result shown in FIG. 1, the γ-NiOOH generation rate of each battery is a relative value when the γ-NiOOH generation rate of the battery A1 is 100.

As is clear from the results shown in FIG. 2, when the amount of solid solution of copper is in the range of 0.5 to 5% by weight, γ-NiOOH
It can be seen that the generation rate of is stable. Therefore, by setting such a range as a solid solution amount of copper element,
Generation of γ-NiOOH can be stably suppressed.

In the above experiment for changing the amount of solid solution, an example of the copper element is shown, but other elements, ie, tin,
When using magnesium, zinc, and cadmium alone,
It has been confirmed that a similar tendency can be obtained when two or more of copper, tin, magnesium, zinc, and cadmium are used in combination.

In the above embodiment, the positive electrode active material in which a sodium-containing cobalt compound layer is coated on the surface of nickel hydroxide particles in which elements such as manganese and copper are dissolved is used. It has been confirmed that the same tendency can be obtained when coating with cobalt hydroxide and cobalt monoxide instead of. Furthermore, even when these cobalt compounds are not coated, the formation of γ-NiOOH is suppressed by forming a solid solution element such as copper into a solid solution, and a high active material utilization rate can be obtained over a long period of the charge / discharge cycle. Make sure you can.

Further, in the above embodiment, an alkaline storage battery using cadmium for the negative electrode has been illustrated. However, when a zinc electrode and a hydrogen storage alloy electrode are used for the negative electrode,
It has been confirmed that a similar effect can be obtained.

[0055]

According to the present invention, it is possible to provide an alkaline storage battery capable of obtaining a high utilization rate of an active material over a long charge / discharge cycle.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an alkaline storage battery according to one embodiment of the present invention.

FIG. 2 is a graph showing a relationship between a manganese solid solution amount and a γ-NiOOH generation rate.

FIG. 3 is a graph showing a relationship between a copper solid solution amount and a γ-NiOOH generation rate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Positive electrode 2 ... Negative electrode 3 ... Separator 4 ... Positive electrode lead 5 ... Negative electrode lead 6 ... Positive electrode external terminal 7 ... Negative electrode can 8 ... Sealing lid 9 ... Coil spring 10 ... Insulation packing

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Nobuyuki Higashiyama, 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Mamoru Kimoto 2-chome, Keihanhondori, Moriguchi-shi, Osaka No. 5-5 Sanyo Electric Co., Ltd. (72) Inventor Yasuhiko Ito 2-5-5 Keihanhondori, Moriguchi-shi, Osaka F-term in Sanyo Electric Co., Ltd. 5H003 AA02 AA04 BB04 BC05 BC06 BD04 5H016 AA02 EE05 HH01

Claims (4)

[Claims] At least one element selected from copper, tin, magnesium, zinc and cadmium is dissolved in α-type nickel hydroxide in which manganese is solid-dissolved in an amount of 15 to 50% by weight based on the total amount of nickel and manganese. A non-sintered nickel electrode for an alkaline storage battery, characterized in that the electrode is used as a positive electrode active material. 2. The method according to claim 1, wherein at least one element selected from copper, tin, magnesium, zinc and cadmium is dissolved in a solid solution in an amount of 0.5 to 5% by weight based on the total amount of said element, nickel and manganese. The non-sintered nickel electrode for an alkaline storage battery according to claim 1. 3. Cobalt hydroxide, cobalt monoxide, or a sodium-containing cobalt compound in an amount of 2 to 15% by weight in terms of cobalt element based on the total amount of nickel hydroxide is added to nickel hydroxide or coated with nickel hydroxide. The non-sintered nickel electrode for an alkaline storage battery according to claim 1 or 2, wherein: 4. An alkaline storage battery comprising the nickel electrode according to claim 1 as a positive electrode.