JPH0426062A - Manufacture of zinc-alkali battery - Google Patents

Abstract

PURPOSE:To improve resistance to electrolyte leakage by adding a zinc alloy with a proper composition and a specified amount of indium sulfide to a gel alkaline electrolyte. CONSTITUTION:A gel negative pole 2 is composed of an active mass of a corrosion-resistant zinc alloy powder prepared by adding a proper amount of a proper composition of indium, lead, bismuth, calcium, and aluminum to zinc and a gel alkaline electrolyte prepared by dispersing 0.005-0.5 wt.% of indium sulfied powder as an inorganic inhibitor in the zinc alloy. A part of the indium sulfide is electrodeposited as metal indium on the surface of the zinc alloy and heightens hydrogen excess voltage and the rest of the indium sulfide remains as a solid in the electrolyte and when new zinc alloy surface appears owing to discharging, the rest is electrodeposited on the new surface and shows a corrosion preventing effect. In this way, resistance to electrolyte leakage is improved.

Description

[Detailed Description of the Invention] Fields of Application The present invention uses zinc as a negative electrode active material, alkaline aqueous solution as an electrolyte, manganese dioxide, silver oxide,
The present invention relates to mercury-free technology for zinc-alkaline batteries using oxygen, etc., and provides a method for producing zinc-alkaline batteries that are pollution-free and have excellent storage and discharge performance.

Conventional Technology Approximately ten years ago, there was a strong concern about environmental pollution caused by mercury in waste batteries, and research was conducted into reducing the amount of mercury in alkaline batteries. As a result, with the development of corrosion-resistant zinc alloys, etc., the amount of mercury contained in alkaline dry batteries is currently being reduced to 250 ppm relative to the battery weight. However, now that there is worldwide concern about environmental destruction caused by industrial products, as exemplified by the problem of ozone layer depletion caused by fluorocarbons, there is an increasing demand for the complete elimination of mercury in alkaline batteries.

The approach to mercury-free alkaline batteries is as follows:
This has been done since the time when mercury-containing alkaline batteries were being developed, and numerous applications and publications have been made in patents and Japanese literature regarding various materials related to zinc alloys, inorganic inhibitors, and organic inhibitors.

Indium is a material with a high hydrogen overvoltage and is known as an additive to the negative electrode of secondary batteries, regardless of the type of battery. Many applications and publications have also been made regarding methods of using metallic indium as an alloy additive element and methods of using indium compounds as inorganic inhibitors.

For example, the method of using it as an alloy additive element (Japanese Patent Publication No. 1-
41576), a method using indium oxide and indium hydroxide as inorganic inhibitors (Japanese Patent Publication No. 1973-
36450, JP-A-49-93831, JP-A-49-1
12125, 56th Electrification Conference Lecture Abstracts/Presentation Number 3
GO5; page 205), method of adding indium oxide and cadmium oxide in combination (JP-A-1-105466)
)and so on. In addition, examples of adding it as an additive to the negative electrode of a secondary battery (JP-A-61-96666, JP-A-6L-1
01955) is also available.

In addition, organic inhibitors include jetanolamine,
Oleic acid, lauryl ether, amines, or ethylene oxide polymers have been proposed. Moreover, as an example of the combined addition of an inorganic inhibitor and an organic inhibitor, the combined addition of indium hydroxide and an ethoxylfluoroalcohol-based polyfluoride compound has been proposed (Japanese Unexamined Patent Publication No. 2-79367).

Problems to be Solved by the Invention In batteries that use pure zinc without mercury as the active material of the negative electrode,
A corrosion reaction of zinc accompanied by hydrogen generation occurs violently, increasing the internal pressure of the battery and pushing the electrolyte to the outside, resulting in a problem of reduced leakage resistance.

Additionally, in a partially discharged battery, the rate of hydrogen generation in the zinc negative electrode is accelerated, further reducing leakage resistance.

These results are due to the disappearance of mercury, which was suppressing corrosion reactions, by increasing the hydrogen overvoltage on the zinc surface.

Even with a corrosion-resistant zinc alloy containing indium, aluminum, and lead, which has been proven to have a corrosion-resistant effect by reducing mercury in the zinc negative electrode, if a battery is constructed without mercury, the leakage resistance of the battery after partial discharge cannot be ensured.

In addition, a battery constructed by adding commercially available indium oxide or indium hydroxide to a gel negative electrode using pure zinc powder as the negative electrode active material is as practical as a battery constructed only of the above-mentioned corrosion-resistant alloy. The leakage resistance of the battery cannot be ensured.

A battery can be constructed by using a corrosion-resistant zinc alloy containing indium, aluminum, and lead as the active material for the negative electrode, and adding an organic inhibitor to the gel negative electrode and an amine surfactant that is effective in reducing mercury. , leakage resistance of the battery after partial discharge cannot be ensured.

As described above, the conventional seeds do not have a complete corrosion inhibiting effect, and cannot be said to be practical at least for sealed batteries.

In order to make alkaline dry batteries mercury-free, the present inventors have developed materials that can exhibit the best combined effects of corrosion-resistant zinc alloys, inorganic inhibitors, and organic inhibitors, as well as their optimal conditions. The concentration was investigated.

Means for Solving the Problems First, the present invention will be described in detail regarding the combined use of a corrosion-resistant zinc alloy and an inorganic inhibitor. The gelled negative electrode in the present invention includes indium, lead, bismuth, calcium,
An active material consisting of a corrosion-resistant zinc alloy powder containing an appropriate combination of zinc and aluminum in an appropriate amount, and an indium sulfide powder having appropriate properties as an inorganic inhibitor are dispersed at an appropriate concentration. It is composed of a gel-like alkaline electrolyte.

The above corrosion-resistant zinc alloy contains 0.01 to 1 w of indium.
t%, one or both of lead and bismuth in total of 0.
Zinc alloy containing 0.05 to 0.5 wt%, or 0.01 to 1 wt% of indium, a total of 0.005 to 0.5 wt% of one or both of lead and bismuth, and one or two of calcium and aluminum. 00 in total
It is a zinc alloy containing 0.05 to 0.2 wt% gold. Further, the appropriate amount of indium sulfide added is 0.005 to 0.5 wt% based on the zinc alloy.

Next, the present invention will be described in detail regarding the combined use of a zinc alloy, an inorganic inhibitor, and an organic inhibitor. The gel-like negative electrode of the present invention is made by combining corrosion-resistant zinc alloy powder to which an appropriate amount of indium, lead, bismuth, calcium, and aluminum is added in an appropriate combination, and indium sulfide powder with appropriate properties at an appropriate concentration. and a gel-like alkaline electrolyte to which an appropriate amount of a surfactant having polyethylene oxide as an organic inhibitor in its hydrophilic part and a fluorinated alkyl group in its lipophilic part is added.

The above surfactant is 0.001 to 0.00% for zinc alloy.
It is effective to include it in the alkaline electrolyte at 1 wt%.

In addition, corrosion-resistant zinc alloy contains indium of 001 to 1 w
t%, one or both of lead and bismuth in total of 0.
Zinc alloy containing 0.005 to 0.5 wt%, or 0.01 to 1 wt% of indium, a total of 0.005 to 0.5 wt% of one or both of lead and bismuth, and one or two of calcium and aluminum. 00 in total
It is a zinc alloy containing 0.05 to 0.02 wt% gold. In addition, the appropriate amount of indium sulfide added is 0 to zinc alloy.
It is 0.005 to 0.5 wt%.

Further, from the viewpoint of the battery manufacturing method, it is desirable to use indium hydroxide synthesized by using an indium salt as a starting material and reacting it with hydrogen sulfide in an aqueous solution of the indium sulfide.

In addition, the above indium sulfide has a particle size of 0°5 to 8μ.
of the total amount of particles in the range of 60 wt% or more, preferably 70 wt% of the total amount.
It is effective to use a powder containing at least % by weight.

In addition, the surfactant has the following structural formula (X) )n: 4-1
0 m: 20-100 or (X)-C,F2n(C)12CH=')-(C
H2CH20) --(Z)
0 m: 40 to 100 is effective.

Function: The materials of the corrosion-resistant zinc alloy, inorganic inhibitor, and organic inhibitor of the present invention, as well as the combination and composition of their composites, were discovered as a result of intensive research to maximize the combined effects of each. Although the elucidation of its mechanism of action is currently unclear, it is inferred as follows.

First, the effects of each of the additive elements of the alloy, the inorganic inhibitor, and the organic inhibitor are as follows.

Among the additive elements in the alloy, indium, lead, and bismuth have high hydrogen overpotentials themselves, and when added to zinc, they have the effect of increasing the hydrogen overvoltage on the surface. If they are added uniformly into the alloy, this effect will be retained even if a new zinc surface appears due to the discharge, since the added elements are present at every depth in the powder. Furthermore, aluminum and calcium have the effect of making zinc particles spherical, reducing the true specific surface area, thereby reducing the amount of corrosion per unit weight of zinc powder.

When indium sulfide is dispersed as a powder in a gel-like alkaline electrolyte in coexistence with a zinc alloy, a portion of it is deposited as metallic indium on the surface of the zinc alloy using the principle of displacement plating, increasing the hydrogen overvoltage on the surface. . The remaining part remains as a solid in the electrolyte, and when a new zinc alloy surface appears due to discharge, it is electrodeposited on the new surface and exhibits a corrosion-preventing effect.

The effect of sulfide after discharge is higher than that of hydroxide due to its own low solubility.

When a surfactant coexists with a zinc alloy in a gel-like alkaline electrolyte, it chemically adsorbs onto the surface of the zinc alloy based on the principle of metal soap, forming a hydrophobic monomolecular layer, which exhibits an anticorrosion effect. especially,
Surfactants with polyethylene oxide in the hydrophilic part are
It has high solubility as a micelle in an alkaline electrolyte, and when added to the electrolyte, it quickly migrates and adsorbs to the surface of the zinc alloy, so it has a high anticorrosion effect. Furthermore, if the oleophilic moiety has a fluorinated alkyl group, when it is adsorbed onto the surface of the zinc alloy, it has high electrical insulation properties, effectively eliminating electron transfer during corrosion reactions, and has strong alkali resistance, so its effect is negligible. last.

Next, the combined effect of zinc alloy and indium sulfide will be explained. Since indium sulfide acts by being electrodeposited on the surface of the zinc alloy, the electrodeposition must occur smoothly and uniformly. Since a significant amount of hydrogen gas is generated on the surface of the zinc alloy, which has no corrosion resistance, the electrodeposition of indium is inhibited, and the state of the electrodeposition becomes non-uniform. However, on the surface of a zinc alloy with good corrosion resistance, the generation of hydrogen gas is suppressed, and electrodeposition occurs smoothly and uniformly, resulting in a compound effect. This also applies to the state after partial discharge. In the case of sulfides, because of their low solubility, electrodeposition is slow and the effect is greater than that of hydroxides.

However, on the other hand, it is susceptible to the corrosion resistance of zinc alloys.

Next, the combined effect of the corrosion-resistant zinc alloy, indium sulfide, and surfactant will be explained. The mechanism of action of indium sulfide is as described above, but if all of the indium sulfide is electrodeposited, there will be nothing left to act on after partial discharge. In addition to its own effect, the surfactant is thought to have the effect of suppressing the electrodeposition of more indium than necessary and ensuring the amount of indium that is available after partial discharge.

Next, the meaning of limiting the properties of indium sulfide will be explained. The finer the particle size, the better the dispersibility in the gel electrolyte, and the gel negative electrode can exhibit a uniform effect. However, if it is too fine, it will dissolve all at once, making it impossible to secure enough amount to act after partial discharge.

Next, the meaning of limiting the method of synthesizing indium sulfide will be explained. The properties of indium sulfide vary depending on the synthesis method. The dry method produces non-stoichiometric indium sulfide, which has unstable effects, but indium sulfide synthesized by the wet method is stoichiometric, crystalline, and has excellent anti-corrosion properties.
It becomes a particle shape.

Next, the meaning of limiting the molecular structure of the surfactant will be explained. Surfactants with polyethylene oxide as their hydrophilic part have high solubility as micelles in alkaline electrolytes, and when added to electrolytes, they migrate to the zinc alloy surface,
It has a high corrosion prevention effect because adsorption occurs quickly. In addition, if the terminal end of polyethylene oxide is a hydroxyl group, that is, an alcohol, it is easily hydrolyzed in an alkaline electrolyte.
Phosphoric acid groups are preferred. If a fluorinated alkyl group is present in the lipophilic moiety, when it is adsorbed on the surface of a zinc alloy, it has high electrical insulation properties and effectively eliminates the transfer of electrons in the corrosion reaction. If the bonding group between the hydrophilic part and the lipophilic part is a hydrophilic amide group or sulfoamide group rather than a water-repellent alkyl group, chemical adsorption with zinc will occur at this part, resulting in high corrosion resistance.

EXAMPLES The details and effects of the present invention will be explained below using examples.

First, in order to demonstrate the effects of the method of creating a corrosion-resistant zinc alloy, the method of synthesizing indium sulfide, and the manufacturing method of the present invention, we will explain the structure of the LRe-type alkaline manganese battery used in the examples and the method of comparative evaluation of leakage resistance. do.

Corrosion-resistant zinc alloy powder is produced by melting 99.97% pure zinc, adding specified amounts of specified additive elements, and uniformly dissolving it.
It is made by the so-called atomization method, which is sprayed with compressed air and pulverized, and then classified with a sieve to obtain particles in the particle size range of 45 to 15.
Adjusted to 0 maesongyu. Indium sulfide was obtained by adding a saturated amount of indium chloride or sulfate to an acetic acid aqueous solution, and stirring the aqueous solution with a screw stirrer to react with hydrogen sulfide. The precipitate was washed with ion-exchanged water on a filter with a mesh size of 0.5μ until the oral pH reached 6, the moisture was separated by drawing a vacuum from the bottom of the filter, and the water was vacuum dried at 60°C. It was synthesized by

The gelled negative electrode was prepared as follows. First, 3% by weight of sodium polyacrylate and 1% by weight of carboxymethyl cellulose are added to a 40% by weight potassium hydroxide solution (containing 3% by weight of ZnO) to form a gel. Next, while stirring the gel electrolyte, a predetermined amount of indium sulfide powder is gradually added and dissolved, and the electrolyte is aged for 2 to 3 hours. Furthermore, twice the weight ratio of zinc alloy powder was added to the gel electrolyte and mixed. In addition, when adding the root filament inhibitor, a predetermined amount of this was added to the gel electrolytic solution and aged for 2 to 3 hours before adding indium sulfide in the above-mentioned adjustment step.

Figure 1 shows the alkaline manganese battery LR6 used in this example.
FIG. In FIG. 1, 1 is a positive electrode mixture;
2 is a gel negative electrode characterized by the present invention, 3 is a separator, and 4 is a current collector of the gel negative electrode. 5 is the positive terminal cap, 6 is the metal case, 7 is the battery exterior can, 8 is the case 6
A resin sealing body made of polyethylene closes the opening, and 9 is a bottom plate forming a negative electrode terminal.

The method for comparative evaluation of leakage resistance was to prototype 100 alkaline manganese batteries as shown in Figure 1 and partially discharge them to a depth of 20% of the theoretical capacity at a constant current of IA, which is the most severe condition for LR6. The number of batteries that leaked after storage at 60°C was evaluated as a leakage index (%). Under these harsh conditions, if the leakage index is 0% after 30 days of storage at 60°C, it is practical, but it is desirable to be able to maintain reliability-related performance such as leakage resistance for as long as possible.

Example 1 The present invention will be described in the case where a zinc alloy and an inorganic inhibitor are combined.

First, we investigated zinc alloys by adding various additive elements and varying the composition. As a result, zinc alloys containing indium as an essential alloy component, and lead and bismuth, either singly or in combination, or indium as an essential component, lead and bismuth, either singly or in combination, and calcium. It was found that a zinc alloy system containing aluminum alone or in combination is good when used alone. Table 1 shows the best alloy composition group among them.

Table 1 Corrosion-resistant zinc alloy for mercury-free alkaline zinc batteries (
) indicates the amount of alloy components added> Table 2 shows the leakage test results after storage at 60'C for 60 days for batteries prepared by varying the amount of indium sulfide added to the various zinc alloys shown in Table 1 above.

As shown in Table 2, even zinc alloys with excellent corrosion resistance cannot ensure practical leakage resistance when used alone. However, it can be seen that leakage resistance can be ensured by adding an appropriate amount of indium sulfide. The amount of indium sulfide added to each zinc alloy is preferably in the range of 0.005 to 0.5 wt%.

Table 3 shows the leakage test results after storage at 60° C. for 60 days for batteries prepared by fixing the amount of indium sulfide added at 0.1 wt% and varying the amount of alloy component elements added.

From Table 3, the amount of indium added to the zinc alloy is 0.01
~1 wt%, lead and bismuth each individually or in total 0005~0.5 wt%, or calcium and aluminum each individually or in total 0
．． It can be seen that 0.005 to 0.2 wt% is appropriate.

In this example, indium sulfide synthesized by using sulfate as a starting material and reacting its aqueous solution with hydrogen sulfide was used, but the effect can also be obtained by using indium sulfide using chloride or nitrate as a starting material.

The degree of effectiveness was higher in the following order: those using chloride as a starting material, those using sulfate as a starting material, and those using nitrate as a starting material.

Example 2 The present invention regarding limitation of starting materials in the synthesis of indium sulfide is explained using a composite of a zinc alloy and an inorganic inhibitor.

Table 4 shows the leakage test results after storage at 60° C. for 60 days for batteries in which 0.1 wt % of indium sulfide, which is a different starting material, was added to each zinc alloy.

From Table 4, it can be seen that even nitrates are suitable if they are synthesized in the presence of chloride ions. By the way, even for products using nitrate as the starting material, the leakage index is 0 at 60℃ on the 45th day.
%, which is at a sufficiently practical level, but chloride,
Batteries using sulfate as a starting material are heated to 60°C and 75°C.
It may not leak until the next day.

Example 3 An example of limiting the particle size range of indium sulfide will be described in the case where a zinc alloy and an inorganic inhibitor are combined.

Table 5 shows the leakage test results after 60 days at 60°C for batteries in which 0.1 wt% of indium sulfide having different particle size distributions was added to each zinc alloy.

From Table 5, 60% of particles with particle diameters in the range of 0.5 to 8μ
It is preferable to use indium sulfide powder containing wt% or more (because the particles remaining on the filter with a coarseness of 0.5 μm in the water washing step of synthesis are used, the remaining particles are particles of 8 μm or more). If those particles contain 70 wt% or more, 6
There may be no leakage even after 75 days at 0°C.

The indium sulfide having different particle size distributions used in this example used nitrate as a starting material, and those with large particle sizes were classified and adjusted by a wet sedimentation method.

Example 4 An example will be described in which a zinc alloy, an inorganic inhibitor, and an organic inhibitor are combined.

Table 6 shows the batteries prepared at 60℃ for each zinc alloy by fixing the amount of indium sulfide added to the optimal 0.1 wt% and varying the amount of surfactant, which is an organic inhibitor.
The results of a leakage test after 60 days of storage are shown.

From this, the amount of surfactant added is 0.0 for each zinc alloy.
It can be seen that 01 to 01W [%] is appropriate.

Even when an organic inhibitor is added, as in the case where a zinc alloy and an inorganic inhibitor are added in combination, the composition of the zinc alloy is that indium is 0.01 to 1 wt%, and lead and bismuth are contained individually or in total. at 0.0
05-0.5wt%, or calcium and aluminum, each alone or in total, 0.005-0
．． 2 wt% was appropriate.

The surfactant used in Example 4 has the following structural formula (X) :60 I used something that is.

The following structural formula (X) H(X)-C2F 2n(CH2CH2)-(CH2CH
20) m-(Z)X -H or -F Z l-CH3-pQ3W2 or -8O3W+W is an alkali metal) n: 4-1
If the surfactant has a ratio of 0 m:40 to 100, similar or better effects can be obtained. Note that among the above-mentioned surfactants, the phosphoric acid type surfactants may be a mixture of primary and secondary phosphates.

In addition, indium sulfide is made from sulfate as a starting material, and its particle size is 80wt% in the range of 0.5 to 8μ.
Example 2, real side 3 and example 4 with the powder containing the above
It has been confirmed that sufficient or better leakage resistance can be obtained using indium sulfide having the same properties as the starting material shown in .

Incidentally, in all the examples, the effects of the present invention have been explained using a non-icing zinc alloy, but the effects are sufficient even in the case of extremely low icing, where the amount of mercury added is several PPM to several tens of PPM.

Effects of the Invention As described above, according to the present invention, in a zinc alkaline battery, a zinc alloy having an appropriate composition in a gel alkaline electrolyte and indium sulfide having appropriate physical properties by an appropriate synthesis method are used. By adding mercury-free, it is possible to suppress the increase in battery internal pressure due to gas generation due to corrosion of zinc, thereby achieving a more complex effect than expected and improving the leakage resistance of the battery. By adding an appropriate amount of an organic inhibitor having an appropriate structural formula to this, a pollution-free zinc-alkaline battery with even better storage stability can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an alkaline manganese battery in an embodiment of the present invention. 1... Positive electrode mixture, 2... Gel-like negative electrode, 3... Separate

Claims (12)

[Claims] (1) In preparing a gel-like negative electrode in which zinc alloy powder is mixed and dispersed in a gel-like alkaline electrolyte, a zinc alloy containing at least one member from the group of indium, lead, bismuth, calcium, and aluminum is used as an active material, A method for manufacturing a zinc-alkaline battery, characterized in that the alkaline electrolyte contains indium sulfide in an amount of 0.005 to 0.5 wt% based on the zinc alloy. (2) 0.01 to 1 wt% of indium and 0.005 to 0.5 wt of one or both of lead and bismuth in total
% of zinc alloy is used as a negative electrode active material. (3) 0.01 to 1 wt% of indium and 0.005 to 0.5 wt of one or both of lead and bismuth in total
Claim 1, characterized in that a zinc alloy containing a total of 0.005 to 0.2 wt% of one or both of calcium and aluminum is used as the negative electrode active material.
A method for producing a zinc-alkaline battery as described in Section 1. (4) Indium sulfide uses indium salt as a starting material,
The method for manufacturing a zinc-alkaline battery according to claim 1, wherein indium sulfide is synthesized by reacting hydrogen sulfide in an aqueous solution of the indium sulfide. (5) The synthesized indium sulfide has a particle size of 0.
2. The method for producing a zinc-alkaline battery according to claim 1, wherein the zinc-alkaline battery contains 60 wt% or more of the total amount of particles having a size of 5 to 8 μ. (6) In preparing a gelled negative electrode in which zinc alloy powder is mixed and dispersed in a gelled alkaline electrolyte, a zinc alloy containing at least one member from the group of indium, lead, bismuth, calcium, and aluminum is used as an active material, The alkaline electrolyte contains indium sulfide in an amount of 0.005 to 0.5 wt% based on the zinc alloy, and further contains a surfactant having polyethylene oxide in the hydrophilic part in an amount of 0.001 to 0.5 wt% based on the zinc alloy. A method for manufacturing a zinc-alkaline battery characterized by containing 0.1 wt%. (7) 0.01 to 1 wt% of indium and 0.005 to 0.5 wt of one or both of lead and bismuth in total
7. The method for manufacturing a zinc-alkaline battery according to claim 6, characterized in that a zinc alloy containing % of zinc is used as a negative electrode active material. (8) 0.01 to 1 wt% of indium and 0.005 to 0.5 wt of one or both of lead and bismuth in total
Claim 6, characterized in that a zinc alloy containing a total of 0.005 to 0.2 wt% of one or both of calcium and aluminum is used as the negative electrode active material.
A method for producing a zinc-alkaline battery as described in Section 1. (9) Indium sulfide uses indium salt as a starting material,
The method for manufacturing a zinc-alkaline battery according to claim 6, wherein the indium sulfide is synthesized by reacting hydrogen sulfide in the aqueous solution. (10) The synthesized indium sulfide has a particle size of 0
．． 7. The method for producing a zinc-alkaline battery according to claim 6, wherein the zinc-alkaline battery contains 60 wt% or more of the total amount of particles having a size of 5 to 8 μ. (11) The surfactant having polyethylene oxide in the hydrophilic part has the following structural formula (X)-C_nF_2_n-(Y)-(CH_2CH_
2O)_m-(Z)
0 m: 20 to 100. The method for producing a zinc-alkaline battery according to claim 6. (12) A surfactant having polyethylene oxide in its hydrophilic part has the following structural formula (X)-C_2F_2_n-(CH_2CH_2)-(
CH_2CH_2O)_m-(Z)X:-H or-
F Z: -CH_3, -PO_3W_2 or -SO_3W {W is an alkali metal} n: 4 to 1
0 m: 40-100 The method for manufacturing a zinc-alkaline battery according to claim 6.