JPS583974B2 - Antenna NIOOH - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for the production of stable NiOOH by mixing an alkali metal hydroxide with nickel hydroxide and ozonizing the resulting mixture.

More specifically, nickel hydroxide is mixed with potassium hydroxide, sodium hydroxide, lithium hydroxide, rubidium hydroxide or cesium hydroxide, and the resulting mixture is then dry ozonated.

The resulting stable Ni00H is a useful cathode material in both primary and secondary batteries.

In recent years, nickel zinc
couple) has been the subject of extensive research and experimentation.

Recent studies have shown that this system is rechargeable, and the well-known long-life capabilities of nickel electrodes combine with the high efficiency, high energy density of zinc electrodes to make them practical high-energy secondary batteries. give.

However, there has been little commercial success in the field of primary Nickel zinc batteries.

The main reason for this lack of success is that the nickel oxyhydroxide used as the cathode material in such cells has been unstable.

The form of nickel oxide commonly used in these primary batteries is trivalent nickel oxyhydroxide, which is usually an electrochemical oxidation of nickel hydroxide and an alkaline electrolyte based on KOH as the main component. Alternatively, it is produced by a method such as ozonizing nickel (n) hydroxide at a temperature of 20°C to 110°C.

However, when such trivalent nickel oxyhydroxide comes into contact with an alkaline solution, it releases oxygen according to the following formula.

4Ni00H+2H20=4Ni(OH)2+02 This evolved oxygen has a detrimental effect on battery capacity and capacity maintenance, and can also cause batteries using it to swell or even explode.

Recently, it has been discovered that high valence amorphous nickel oxides can be stabilized in their high valence state and can be effectively electrochemically utilized as cathode materials for primary batteries.

Tetravalent nickel oxyhydroxide is now recognized as meeting the requirements for use as a cathode material in primary batteries.

It has been shown that stable tetravalent nickel oxyhydroxide can be produced electrochemically.

For example, the Journal of the Electrochemical Society
Blectrochemical Society)
, January 1965 issue, pages 1-12, Tuom
See paper i).

In this paper, Tsuomi describes the production of "tetravalent nickel" by charging crystalline Ni(OH)2 with 125 mA for 17 days in a suitable electrolyte.

We have now invented a new method for producing stable tetravalent nickel oxyhydroxide, which is useful as a cathode material in both primary and secondary batteries.

The present invention relates to a process for producing stable tetravalent nickel oxyhydroxides by mixing an alkali metal hydroxide with nickel ((I) hydroxide) and dry ozonating the resulting mixture.

We have invented a new method for producing stable tetravalent nickel oxyhydroxides that are effective and efficient cathode materials for use in both primary and secondary batteries.

In the formula -Ni2ox- (nickel oxyhydroxide)
If X in this formula is greater than 3.0, then the product is trivalent.If X in the formula is greater than 3.0, the product is at least partially tetravalent.

Ideally, the product has an X value of 4.0, ie, all compounds are in the tetravalent state.

However, this is the "ideal" state, and for purposes of this invention the term tetravalent refers to nickel oxyhydroxides in which the value of X is greater than 3.0.

In the method of the present invention, a dry alkali metal hydroxide is mixed with dry nickel hydroxide, i.e., Ni(OH)2, and the resulting mixture is dry ozonated to produce a stable tetravalent nickel oxyhydroxide. .

Dry nickel hydroxide is readily available commercially.

As used herein, the term dry alkali metal hydroxide refers to the hydroxides of potassium, sodium, lithium, cesium, rubidium and mixtures thereof in dry form, with potassium hydroxide being the preferred material.

Although these alkali metal hydroxides often contain bound water, those supplied in solid form by the manufacturer can be used for the purposes of the present invention.

The amount of alkali metal hydroxide to be mixed with nickel hydroxide is about 5 to about 40% by weight based on the weight of dry nickel hydroxide.
Weight%.

Depending on the particular alkali metal hydroxide used to make the stable nickel oxyhydroxide, effective concentrations for each of the above alkali metal hydroxides are as follows: Potassium hydroxide from about 5 to about 40% by weight Sodium hydroxide Approximately 5 to 30% by weight Cesium hydroxide Approximately 5
~about 40% by weight rubidium hydroxide; about 5% to about 40% by weight lithium hydroxide; about 5% to about 20% by weight nickel hydroxide and the alkali metal hydroxide can be mixed by any known method in the art. can.

For example, dry nickel hydroxide is placed in a ceramic ball mill, pellets of a given alkali metal hydroxide are ground into a fine powder using a mortar and pestle, and the ground alkali metal hydroxide powder is placed in a ceramic ball mill. May be added to one nickel.

The mixture is then ball milled for about 30 minutes or until a fine powder is obtained, and the resulting fine powder can then be passed through a sieve, for example, 50 mesh, to remove large particles prior to ozonation.

The mixture thus obtained is then ozonated in a suitable manner.

For example, the mixture may be transferred from a ball mill to an Erlenmeyer flask, and the flask may be rotated by a small motor while ozone is passed over the mixture in the rotating flask.

Ozone oxidizes the nickel hydroxide-alkali metal hydroxide mixture to form nickel oxyhydroxide (nickel oxide).

This consists of green Ni(OH)2 immediately changing to black Ni00HrNI203.H20j according to the following formula.

03+2Ni(OH)2→2Ni00H+H20+02
Subsequent ozonation leads to the formation of a mixture of black and gray trivalent and tetravalent nickel oxides.

At the end of the ozonation process, most of the nickel hydroxide is converted into gray tetravalent nickel oxide Ni (OH
)4 Changes to “Ni02・2H20”.

03+2NIOOH+3H20→2Ni02.2H20+02 As can be seen from Table 1, the presence of an alkali metal hydroxide is effective for this reaction to proceed.

The color of the mixture turns gray and the average valence of the oxide is 3.0.
Ozonation is continued until it indicates that a tetravalent state greater than 0 has been reached.

Ozonation can be carried out at room temperature, however, if low temperature ozonation is desired, the rotating flask can be immersed in a cold bath of running water.

The resulting product is a stable tetravalent nickel oxyhydroxide that can be effectively used in cathode production for both primary and secondary batteries.

For example, 725 type and 825 type primary cells can be produced by incorporating a stable nickel oxyhydroxide cathode prepared by the method of the present invention into a typical cell of appropriate size.

Such cells have a two-part container: an upper part, a cap, which contains the negative electrode or anode, and a lower part, the cup, which contains the positive electrode or cathode.

Useful anode materials include cadmium, indium, zinc, magnesium, aluminum, titanium and manganese, with cadmium, indium and zinc being preferred, and gelled or semi-gelled zinc being most preferred.

The bottom cup can be made of any suitable material, such as nickel plated steel, and the cap can also be made of any suitable material known in the art, such as tin plated steel.

The cap is insulated from the cup by an insulating sealing collar, which can be made of any suitable electrolyte-resistant material, such as high-density polyethylene or neoprene, to insulate the cap from the container and provide an airtight seal. The collar can be integrally molded around the end of the cap to provide a tight seal.

The negative electrode is separated from the positive electrode by an electrolyte absorber layer and a separator.

The electrolyte absorbent layer can be made of an electrolyte resistant strong absorbent material such as intertwined cotton fibers.

Such materials, for example, have the trade name "Webryl".
It is available as a commercial product.

The product name of the separator layer is “Viskon”
or any suitable semipermeable material, such as the trade name Dexter, "Regenerated Cellulose Material."

A suitable cathode can be selected using the stable nickel oxyhydroxide produced by the method of the present invention.

The stable cathode produced depends on the type of battery being produced and the intended use of the battery.

For example, in a typical 725 or 825 cell, 5 parts of stable nickel oxyhydroxide is dry mixed with 1 part of a carbon material, such as graphite, to increase the conductivity of the mixture.

Part 1 [trade name Whitcon-8''] is added to this dry mixture to act as a binder and lubricant.
Electrolyte Prewet 75 consisting of polytetrafluoroethylene resin and 50% potassium hydroxide
You can add a person in charge.

These ingredients can be prepared, for example, by Batterson-Kelly (Patte).
rson-KelIey) blender or atsuba (
(Abbe) mixer or any other mixer.

Once the mixture is homogeneous, the cathode mixture is pelletized using suitable equipment.

The pellet thus produced is then inserted into the cup of the lower part of the cell.

This serves as a positive electrode or cathode.

EXAMPLES The following examples are intended merely to illustrate the invention and are not intended to be limiting.

All quantities are by weight unless otherwise stated.

Example 1 Nickel(I) hydroxide (Ni) containing 1% Co(OH)2
Samples (50 g in total) of (OH)2) were prepared.

Potassium hydroxide pellets were ground into fine powder and each nickel hydroxide sample was mixed with 1, 5, 10, 15, 20.
Added in amounts of 25 and 30 parts by weight.

This was then ball milled for 15 minutes and then ozonated in a WeIsbach osonizer model T-408 at low temperature, ie at about 15 DEG C., for 3 hours.

Another nickel hydroxide sample was prepared and ozonated as described above, but without the potassium hydroxide.

After ozonation, potassium hydroxide was added to the NiOOH in amounts of 1.5, 10, 15, 20.25, and 30 parts by weight as described above.

Place 1 g samples of the ozonated mixture prepared above into separate 12 cc centrifuge tubes and fill the tube voids with 50% KOH.
A gas generation test was conducted by filling the tank with

The tubes were placed in a glycol bath maintained at a constant temperature of 63°C (145°F).

Each sample was tested three times.

Gas evolution was observed at the height of the KOH solution and the stoppered pipette above the centrifuge tube.

Gas evolution rate was expressed in cc of gas per gram of test material per test day.

Moisture measurements were performed on a Cenco moisture balance.

The data in Table 2 below shows that when KOH is added in an amount of 10 parts or more before ozonation, a very stable nickel oxyhydroxide is obtained and gas generation is greatly reduced.

The total gas collected per gram of untreated control was 3.06 CC per gram of nickel oxyhydroxide after one week of testing.

When KOH was added to the nickel oxyhydroxide after ozonation, the gas generation of the nickel oxyhydroxide was somewhat reduced.

For example, the total gas amount after one week was 1.97, 1.45 and 1.10 CC/g for 10, 15 and 20% KOH additions, respectively.

Figures 1 and 2 show these results.

However, surprisingly, adding KOH at a concentration of 10 to 30 parts before ozonation according to the method of the present invention was very effective in suppressing the gas generation of nickel oxyhydroxide.

For example, the total amount of gas generated after one week is 10.1 after adding KOH.
They were 0.45, 0.20 and 0.15 cc/g for 5 and 20 units, respectively.

See Figures 1 and 2 for graphical representations of these results.

Example 2 A 725 type battery was assembled and tested.

Each battery has an outer diameter of 18.69 to 18.75 mm (0.736
~0.738 inch), height 5.3~5.8 mm (0.738 inch), height 5.3~5.8 mm (0.
210-0.230 inch) and volume 1.56 cm3
(0.095 to cubic inch).

The cell has a two-part container consisting of an upper portion, a cap, containing the negative electrode or anode, and a lower portion, the cup, containing the positive electrode or cathode.

The bottom cup is made of nickel plated steel and the cap is made of tin plated steel.

The cap is insulated from the cup by a polyethylene insulating sealing collar, integrally molded around the end of the cap to insulate the cap from the cup and provide a hermetically sealed seal.

The negative electrode of this cell consists of gelled or semi-gelled zinc.

The zinc electrode is fused from the positive electrode by an electrolyte absorber layer and a separator.

The electrolyte absorbent layer consists of electrolyte resistant, highly absorbent intertwined cotton fibers.

The first layer of the separator is Viscon. The depolarizer was in the form of pellets, and one pellet per battery was inserted into the battery.

The dry cathode mixture was made of nickel oxyhydroxide (Ni0
0H) and 1 part of graphite, to this dry mixture,
1 part of "Witcone 8" which acts as a binder and lubricant, 7.5% of 50 part KOH-50% H20 solution (
Weight Section) added.

Combine the above ingredients in a Patterson-Kelly blender (Patte).
After thorough mixing in a C.Rson-Kelley blender and the mixture was homogeneous, pellets were made from the cathode mixture in a suitable pelletizing machine.

Each pellet weighed 1.69±0.01 g.

See Table 3 for test results. As can be seen from the above data, the tetravalent Ni produced by the method of the present invention
Primary cells using OOH depolarizers (2, 3.4 and 5)
Battery expansion is greatly reduced.

Potassium hydroxide and sodium hydroxide are preferred alkali metal hydroxides because they provide a high flash current to the battery and reduce impedance.

When using hydroxides such as 6 and 7, trivalent Ni00H
This caused significant expansion of the battery at high temperatures.

Example 3 An 825 type battery was assembled in the same manner as the 725 type battery in Example 2, except that the following dimensions were changed.

Battery outer diameter 22.86-22.99mm (0.900-
0.905 inch) Battery height 5.54-5.79 mm (0.218-0.
(228 inches) Volume 1.90 cm3 (0.116 cubic inches) Weight 8.50 grams (0.3 ounces) Each depolarizer pellet weighed 1.79±0.01 g.

See Table 4 below for test results.

As can be seen from the above data, in the primary battery using the NiOOH depolarizer produced by the method of the present invention, that is, by adding 15% NaOH or 15% KOH before ozonation, NiOOH is surprisingly stable in the battery. One result is that the degree of cell expansion is unexpectedly low and also exhibits good capacity retention.

Embodiments of the invention are as follows.

(1) The method according to the claims, wherein the alkali metal hydroxide is potassium hydroxide.

(2) The amount of potassium hydroxide present in the mixture is about 5 to
(3) The method according to claim 1, wherein the alkali metal hydroxide is sodium hydroxide.

(4) The amount of sodium hydroxide present in the mixture is approximately 5
The method of paragraph (3) above, wherein the weight ratio is ˜30% by weight.

(5) The method according to the claims, wherein the alkali metal hydroxide is lithium hydroxide.

(6) The amount of lithium hydroxide present in the mixture is about 5 to
The method according to paragraph (5) above, wherein the weight ratio is about 20% by weight.

(7) A method according to the claims, in which dry ozonation is carried out at room temperature.

(8) The method according to the claims, in which dry ozonation is carried out at about 15°C.

[Brief explanation of drawings]

FIG. 1 is a graphical representation of the gas evolution rate of a stable nickel oxyhydroxide depolarizer prepared according to the method of the present invention plotted against time in days. Figure 2 is a graphical representation of the gas evolution rate plotted against time in days for a nickel oxyhydroxide depolarizer in which an alkali metal hydroxide is added after ozonizing nickel hydroxide. It is.

Claims (1)

[Claims] 1. Mixing an alkali metal hydroxide selected from the group consisting of sodium hydroxide, potassium hydroxide, cesium hydroxide, lithium hydroxide, and rubidium hydroxide with nickel hydroxide, and dry ozonating the resulting mixture. ,
A method for producing a stable tetravalent nickel oxyhydroxide, characterized in that the amount of alkali metal hydroxide in the mixture is 5 to 40% by weight relative to the weight of first nickel hydroxide.