JPS60105170A - Electroconductive silver oxide and silver oxide battery - Google Patents

Abstract

PURPOSE:To decrease electric resistance and impedance of a battery by using silver oxide prepared by adding a mixture of silver salt and nickel salt having a specific molar ratio of silver and nickel in alkaline solution and oxidizing the coprecipitation obtained. CONSTITUTION:A nickel salt such as Ni(NO3)2 and silver salt such as AgNO3 are mixed so that molar ratio of Ni atom to Ag atom is 0.01-0.20. The mixture is poured into alkaline solution such as KOH, and K2S2O8 is added as the solution is stirred. The coprecipitation is filtered, washed, dried, and crushed to obtain electroconductive silver oxide powder. This silver oxide is used as cathode material of a battery. A silver oxide battery suitable for power source of a watch, is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a silver oxide battery using a dielectric silver oxide as an anode material.

Conventionally, silver oxide batteries, which have flat voltage characteristics and a large discharge capacity ti, have been frequently used as small batteries installed in vehicles such as Jigen 1.

By the way, silver oxide Ag20 is used as the anode active material of this silver oxide battery, but since this Ag20 is close to an insulator, when used as the anode active material of the above battery, carbon or graphite, for example, is used. It is common to use a mixture of electrically conductive auxiliary substances such as these to impart electrical conductivity.

In this case, for example, the relationship between the amount of graphite mixed in and the internal resistance of the battery is as shown in FIG.
It is necessary that the amount of graphite mixed in with respect to 20% is 3 parts by weight or more; if it is less than this, the internal resistance becomes too large and the above battery cannot be put to practical use.

When the proportion of conductivity aids such as graphite increases in this way, the specific gravity of these conductivity aids is small, so they occupy a considerable volume in the anode material.

Therefore, although the above-mentioned internal resistance problem is solved, the amount of silver oxide AJ20 in the anode material inevitably decreases, and the discharge capacity of the battery becomes small.

-In electronic equipment such as watches and watches, miniaturization and thinning,
As the silver oxide batteries, which are the drive power sources built into these devices, are becoming more multi-functional, they are required to be smaller and thinner, and also have larger capacities. requested. Therefore, the reduction in discharge capacity caused by the conductive aids described above is a major obstacle to miniaturization of the silver oxide batteries.

The inventors of the present invention, as a result of intensive studies in order to eliminate the drawbacks of the above-mentioned conventional products, found that when preparing silver oxide from silver salt, by adding nickel salt in a predetermined ratio and further adding an oxidizing agent to the silver oxide. It was discovered that silver oxide with good conductivity could be obtained, and the present invention was created by combining silver salt with a mixing ratio such that the molar ratio of Ni atoms to He9 atoms was 0 and Ol to H20. It is characterized in that it is prepared by adding nickel salt to an alkaline aqueous solution and allowing an oxidizing agent to act on the coprecipitate obtained, and further adding it to the +SS of the battery.
It is characterized by being used as an old system.

Generally, silver oxide can be easily obtained by adding silver nitrate A y N O3 to an alkaline solution, but in the present invention, when adding the silver nitrate to the alkaline solution, nickel is added in a predetermined ratio to the silver nitrate. Very good conductivity can be achieved by simply mixing a salt, such as nickel nitrate (Ni(NO3)2), and allowing an oxidizing agent such as potassium peroxysulfate to act on the coprecipitate that forms when such a mixture is added to an alkaline solution. A conductive silver oxide is prepared.

Therefore, the above-mentioned conductive silver oxide can be prepared by an extremely simple method, and can be used as it is as an anode layer of a battery, and the process of mixing conductive auxiliary materials etc. can be omitted when manufacturing batteries. It is extremely useful for improving battery productivity.

By the way, the details of what kind of substance the conductive silver oxide obtained by the above preparation method is made of are unknown, but for example, A720 is the main substance, ApNiO
It is thought that it is a mixture of 2 and a substance with good conductivity.

That is, when silver nitrate and nickel nitrate are added to an alkaline solution, for example, a potassium hydroxide solution, N i (N
o:l)2+2KO11-N i (011)2-1
-2KN(h2AyNO382KOI-1-Ag2O+
By the reaction shown as 2KNO3-1-1-120, nickel hydroxide N1(Ol4)2 and silver oxide A90 are produced, and a coprecipitate of nickel hydroxide N1(Ol4)2 and silver oxide A90 is precipitated.

When this coprecipitate is oxidized by the action of the oxidizing agent potassium peroxysulfate, the upper i6 nickel hydroxide becomes nickel oxyhydroxide (N i 001.1), which is the 511'l separation of AirzO in an alkaline solution. By reacting with AyO- generated by, N i 001-1 +Ag0-- AyN i 02
1ilJIQL as an anode active material as shown in 10H-
;! , generate AyNiOz with conductivity and proceed to the above 2
Mixed in 20.

While doing so, the electrical conductivity obtained is 1-silver oxide ()
When analyzed, only the peak of silver oxide At7zO was confirmed. However, when analyzing the composition of conductive silver oxide, the ratio of A1 atoms to N1 atoms was found to be mixed. It is likely that they are involved in some way.

On the other hand, when preparing the above conductive silver oxide, the mixing ratio of silver salt and nickel salt poses a problem. According to experiments conducted by the present inventors, the molar ratio of Ni atoms to 87 atoms is Ni /Al
l must be in the range of 0.01 to 0.20, and 0
．． It has been found that a Kokichi range of 0.025 to 0.15 is more preferred. Well, the above N1/A9 is 0. O
When it is less than 1, the resistance value of the resulting conductive silver oxide increases rapidly, making it difficult to use it as an anode layer of a battery. On the other hand, if the above Ni/A9 exceeds 0.20, the energy density of the resulting conductive silver oxide becomes small, and for example, when used as an anode layer of a battery, it is difficult to use conventional silver oxide mixed with graphite. There will be no significant difference in discharge capacity from batteries using this type of battery.

As mentioned above, the conventional method of imparting electrical conductivity to silver oxide was to mix conductive substances such as carbon and graphite into the silver oxide. Since it can be filled with T1, it is possible to create a large-capacity silver oxide battery, and the industrial value is extremely large.

Specific examples of the present invention will be described below, but it goes without saying that the present invention is not limited to these examples.

Example 1 1 mole of IR nickel Ni (NO3) 2
Solution of concentration 61) m/ and 1 of silver nitrate A Y No 3
Mix 1000 m/m of solution of molar Zla degree and add this to 1
The mixture was poured into an aqueous solution of potassium hydroxide IgO11 with a concentration of 0 mol/l. While stirring the mixture thoroughly, 16.7 g of 2S20B was added to the oxidizing agent, potassium berooxo(uf).
4','t for about 6 more hours while keeping 1 at 800G.
Continued 41'.

The generated precipitate was filtered, thoroughly washed with pure water, dried under vacuum at 80°C and pulverized to obtain conductive silver oxide powder.

The obtained conductive silver oxide was analyzed by X-ray diffraction, and the diffraction X-ray spectrum was as follows:
It was the same as the line spectrum.

In addition, the obtained conductive silver oxide powder was dissolved in nitric acid, and the silver content was determined by titration with ammonium thiocyanate.
The nickel content was determined by TA titration. It was found that the silver content in this superfruit powder was 88.60% by weight, and the nickel content was 2.811% by weight.

Therefore, the atomic ratio N1/kg in the above powder is 0.0
5 Ill, which was extremely close to the theoretical value of 0.06 calculated from the amounts of nickel nitrate and silver nitrate initially added.

The conductive silver oxide powder obtained in this way was molded with a diameter of 11 mm without changing the molding pressure. QVLjII, thickness Q, 97
It was molded into a Jl# pellet and its electrical resistance was measured.

The results are shown in Figure 2 in comparison with the conventional results. In addition, the second
In the figure, a is the conductive silver oxide obtained in Example 1, b is Ayzo mixed with 3.5 weight percent of graphite,
C is 8720 mixed with 5 weight of graphite, d
1 shows A920 mixed with 8 weights of graphite.

From FIG. 2, the conductive silver oxide obtained in this example is
It can be seen that the resistance value is lower than that of the conventional silver oxide A 720 mixed with 5% by weight of graphite.

Furthermore, the energy density of the obtained conductive silver oxide was measured while changing the molding pressure. The results are shown in FIG. 3 in comparison with the conventional results. In addition, in this Figure 3, a-d
are a~dll! in Figure 2 above. : Shows the same thing, and C shows the case where Ay20 was used alone.

From FIG. 3, it can be seen that the conductive silver oxide produced in this example has a higher energy density than that of Ag2O mixed with 3.5% of graphite by weight, and that it has a higher energy density than that of Ag2O mixed with 3.5% of graphite by weight.
~55 ton/c+#), it can be seen that the energy density is close to that when A7□O is used alone. Therefore, it is clear that the discharge capacity can be increased by using the obtained 1[ conductive silver oxide in a 11 silver oxide battery.

Example 2 A solution of nickel (NO3) 2 with a concentration of 1 mol/l 94 +++/' and a solution of silver nitrate A9NO3 with a concentration of 1 mol/l 10 (Jon/) were mixed, and the solution of the previous example was prepared. Conductive silver oxide was obtained in the same manner as in Example 1.

The energy density of the conductive silver oxide obtained is indicated by f in FIG. In FIG. 3, there is a decrease in energy density of about 20 mH/ca in the product obtained in this example compared to that obtained in Example 1, but there is no problem in practical use.

In this way, increasing the ratio of nickel atoms reduces the energy density of conductive silver oxide, and for practical use the molar ratio of N1 atoms to AyLi atoms must be A9/
It is thought that it is necessary to keep Ni at 0.20 or less, preferably at 0.15 or less.

Example 3 The conductive silver oxide obtained in Example 1 was used at 5 tons/
cA molding pressure and diameter 11. Q ru+, thickness Q, 9
It was molded into m+a nohereso+-1. This was placed in a battery anode can 2, as shown in FIG. 4, and used as an anode material.

Next, a separator 3 made of a cellophane sheet and a cotton nonwoven fabric was placed on the pellet 1, and a 28% NaOH solution was added as an electrolyte.

It showed the same performance as the one that was used.

Example 6 Using the conductive silver oxide obtained in Example 2 above, a battery was produced in the same manner as in Example 3 above.

The battery produced in this example has a higher capacity than that obtained in the previous example 3. It was 11 times smaller.

The internal resistance of the batteries prepared according to Examples 3 to 6 above was measured, and the relationship between the molar ratio Ni /A9 of Ni atoms to Heg atoms and the internal resistance (1) is shown in Figure 5. , in FIG. 5, A is Example 3 and B is Example 4.
, C shows the value of the internal resistance of Example 5, and D shows the value of the internal resistance of Example 6.

From this figure 5, considering the internal resistance of a practical battery,
Molar ratio of Ni atoms to the above AV atoms Ni/AF
must be at least 0.01 or more, and 0
．． It is preferable that it is 025 or more.

[Brief explanation of drawings]

Figure 1 shows a crab eye 1- mixed with silver oxide, and it is 11.6 mm in diameter and 3.5 mm thick. Figure 2 is a graph showing the relationship with the battery internal resistance when used in Onuj+ batteries. FIG. 3 shows a club whose energy density is compared with that of a conventional club. FIG. 4 is a sectional view showing the structure of a silver oxide battery to which the present invention is applied. FIG. 5 is a chart showing the relationship between the molar ratio Ni/Ay of Ay atoms and Ni atoms contained in conductive silver oxide and the internal resistance of the battery produced. 1... Pellet (anode material) patent applicant
Sony ζ Party (Seido Kagaku Kogyo (official agent, patent attorney Kodo Koike 1) Eiji Mura - 1st plan 7 items > Quantity %) -11→
Figure 2: Gushi, To Colored Rito -11→ Figure 3: Dare, l-+5wne & -□--Chi Figure 4: Figure 5 NJ/A38

Claims (1)

[Claims] 1) The molar ratio of Nl atoms to AgJj X atoms is 0.0.
Conductive silver oxide prepared by adding a silver salt and a nitrogen salt to an alkaline aqueous solution at a mixing ratio of 1 to 0.20, and allowing an oxidizing agent to act on the resulting coprecipitate. 2) Adding a silver salt and a nickel salt to an alkaline aqueous solution at a mixing ratio such that the molar ratio of Ni atoms to Ay atoms is 0.01 to 0.20, and allowing an oxidizing agent to act on the resulting coprecipitate. A silver oxide battery comprising conductive silver oxide prepared by the method as an anode material.