JPS6235455A - Manufacture of cathode for alkaline storage battery - Google Patents

Abstract

PURPOSE:To curtail the time required for formation and to improve application coefficient as active substance for electrode by obtaining nickel hydroxide through reaction of dispersed nickel salt, caustic alkali and specified amount of water and forming a cathode using such nickel hydroxide as the active substance. CONSTITUTION:The crushed caustic soda is added to the organic dispersion medium which does not dissolve nickel salt and caustic alkali and these are sufficiently stirred. In this timing,the crushed nickel salt is added to the dispersion medium and the water of 4-8mol is added to nickel of 1mol. Thereby, nickel hydroxide is produced by reaction of these. It is then filtered through attraction by a filter paper. Water is then added for washing. It is then dried, roughly crushed, washed by water dried finnaly and then crushed to obtain the completed active substance. A conductive material is added to such active substance powder and a sponge type metal porous material is filled with such mixed powder. Thereafter it is pressed to a constant thickness to form the cathode. Thereby, the cathode, which may be formed easily, assures high filling coefficient of active substance and high application coefficiency and results in high energy density, may be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a method for producing a nickel anode for an alkaline storage battery, and more particularly to a method for producing a nickel hydroxide anode active material.

(b) Conventional technology Nickel anodes for alkaline power storage and other applications that use nickel hydroxide as an active material (hereinafter referred to as anodes) are based on the quality of the characteristics of the nickel hydroxide, which is the active material, which is a major factor in determining the performance of the electrode plate. The basic manufacturing method of this active material is described in Japanese Patent Publication No. 44-28415, Japanese Patent Publication No. 48-2385, and Japanese Patent Publication No. 52-2094.
A precipitate obtained by reacting a nickel salt aqueous solution such as nickel nitrate or nickel sulfate with a caustic alkali aqueous solution such as sodium hydroxide or potassium hydroxide (neutralization method), which is then dehydrated, washed with water, dried, and coarsely pulverized. After undergoing processes such as , washing with water, drying, and pulverization, it becomes a completed active material. In this method for producing an active material, the precipitate obtained by reacting a nickel salt with a caustic alkali is in the form of a gel, and if washed with water immediately after filtration, the precipitate becomes gel-like again, so that filtration and removal of liquid require a long time. Furthermore, the above-mentioned active materials have a drawback that the utilization rate is not sufficiently high.

On the other hand, Japanese Patent Application Laid-Open No. 53-44844, Japanese Patent Application Laid-open No. 5
New manufacturing methods have been proposed in JP-A No. 6-134471 and JP-A-57-51131, but JP-A-53-44844 uses Ni0c as an active material.
A nickel salt, an oxidizing agent, and a caustic alkali are used in the formation of the nickel hydroxide, and there are problems similar to those of the method for producing nickel hydroxide described above. Further, both Japanese Patent Application Laid-open No. 56-134471 and Japanese Patent Application Laid-open No. 57-51131 have a problem in that the utilization rate of the finished active material cannot be improved.

(c) Problems to be Solved by the Invention The present invention aims to provide a method for producing nickel hydroxide that shortens the time required for production and has a high utilization rate as an electrode active material.

i-J Means for Solving the Problems The method for producing an anode for an alkaline storage battery of the present invention involves adding a nickel salt and a caustic alkali to an organic dispersion medium that does not dissolve them or their reaction product, nickel hydroxide. In this step, 4 to 8 mol of water is dispersed and reacted with the nickel salt, caustic alkali, and 1 mol of nickel to obtain nickel hydroxide, and this nickel hydroxide is used as an active material to prepare an anode. It is something.

The water present in the organic dispersion medium during the above reaction may be added in the form of crystal water or may be added separately, and the total amount is 4S8 moles per 1 mole of nickel. All you have to do is

(e) Effect When adding nickel salt and caustic alkali to an organic dispersion medium that does not dissolve them and reacting, if the amount of water in the organic dispersion medium is 4 to 8 moles per mole of nickel. , the resulting nickel hydroxide does not gel and is produced in granular form,
Furthermore, both the filling rate and the utilization rate of the active material of the anode prepared using the obtained nickel hydroxide as the active material are improved.

In addition, the nickel sulfate used as the nickel salt must contain water of crystallization, and it is also possible to add water to the organic dispersion medium in the form of water of crystallization;
0n・3H20, NiSO4・4H20 and NiSO4
-5H20) are unstable and difficult to exist, and if they are to exist, strict temperature control is required, making them unsuitable for use. When heated, hexa- and heptahydrates change into 0-2 hydrates, but at room temperature they exist stably as 6- and 7-hydrates, so they are suitable for use. It is stable and suitable for use due to its wide temperature range. Therefore, it is desirable that the nickel salt used is a 0-2 hydrate or a 6-7 hydrate.

(f) Examples Fluorinated solvents (manufactured by Daikin ■, 1 Daiflon S-2
''), add 4 moles of crushed caustic soda to the dispersion medium, and while stirring thoroughly, add 1% of crushed nickel sulfate monohydrate (NiSO4.H2O) to the dispersion medium, and then Adding 901 nI! (5 mol) of water,
Six moles of water is present per mole of nickel in an organic dispersion medium, and the reaction is caused to produce nickel hydroxide. Next, it is suction filtered using a filter paper, and water is added and washed, and the washing water is suction filtered, followed by drying, coarse pulverization, water washing, main drying, and pulverization for 200 mesh cycles to obtain a processed active material according to the method of the present invention. . The nickel hydroxide produced by the method of the present invention was granular and did not gel during washing with water.

As a comparison, nickel nitrate is added to 18 l/l of a solution of nickel nitrate to 1/1 of a stirred caustic soda solution of 47 l/l using water as a solvent. was added to produce nickel hydroxide, which was then suction filtered using filter paper, further water was added, washed with water, and the washing water was suction filtered, followed by drying, coarse grinding, washing, main drying, and grinding to produce 200 mesh pieces. However, the nickel hydroxide produced by this conventional method was in the form of a gel. A mixed powder obtained by adding 10% of nickel powder as a conductive material to the above active material powder was used in the form of a sponge. An anode was prepared by filling a porous metal body and pressing it to a constant thickness. The filling rate of the mixed powder, the active material utilization rate, and the time required for the entire process from manufacturing the active material to obtaining the anode in these anodes were measured, and the results are shown in Table 1. In addition, the time required for the entire process is shown as the time required by the conventional method as 100.
As is clear from Table 1, the anode produced by the method of the present invention is easy to manufacture and takes less time than the conventional method.
It can be seen that it is an excellent manufacturing method, as it can be shortened to 100 yen, and the filling rate and utilization rate are also better than the conventional method.

Next, in the same manner as in the above example, nickel sulfate monohydrate was used as the nickel salt, and by varying only the amount of water added, the amount of water present in the organic dispersion medium was varied with respect to 1 mole of nickel. Table 2 shows the results of the same experiment.

Table 2 When adding nickel salt and caustic alkali to an organic dispersion medium that does not dissolve them and reacting to produce nickel hydroxide as an active material, changing the amount of water present in the Rg medium As the amount of water increases, both the filling rate and the utilization rate of the active material of the anode prepared using the obtained nickel hydroxide improve. However, when the amount of water present in the organic dispersion medium exceeds 10 moles per mole of nickel, the resulting nickel hydroxide becomes gel-like and takes time to filter, making the process laborious and lengthy.

Furthermore, if the amount of water present in the organic dispersion medium is less than 4 moles per mole of nickel, the reaction will not proceed sufficiently, and the filling rate of the active material of Gin, whose anode was made using the obtained nickel hydroxide, will also decrease. It was low. On the other hand, when water is present in an amount of 4 to 8 moles per mole of nickel, nickel hydroxide is obtained as granules, which is easy to filter, separate, wash with water, and dry, and does not gel when washed with water. The filling rate and utilization rate of the active material of the anode prepared using nickel oxide were also high and favorable.

(g) Effects of the invention

Claims (1)

[Claims] (1) An alkaline storage battery characterized by using as an active material nickel hydroxide obtained by dispersing and reacting nickel salt, caustic alkali, and 4 to 8 mol of water per 1 mol of nickel in an organic dispersion medium. Manufacturing method of anode for use.