JP2879236B2 - Manufacturing method of electrolytic manganese dioxide for alkaline manganese battery - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing electrolytic manganese dioxide used as a positive electrode active material in a manganese battery or an alkaline manganese battery.

[Prior Art and Problems to be Solved by the Invention] Manganese dioxide is known as an anode active material of a manganese battery or an alkaline manganese battery, and has an advantage of being excellent in storage stability and inexpensive.

In particular, alkaline manganese batteries using manganese dioxide as the anode active material are used in automatic winders, strobes, portable tape recorders, and the like for cameras because of their excellent discharge performance under heavy loads. It is growing.

However, when using an alkaline manganese battery, there is a problem that the discharge potential is difficult to use due to a gradual decrease in the discharge potential, and the discharge time up to an allowable discharge potential in use has been further extended. Batteries are required.

On the other hand, the manganese battery has a problem that the discharge performance under heavy load is inferior.

The present invention has been made in view of the above circumstances, and has an object to provide a production method capable of achieving high performance of electrolytic manganese dioxide used as an anode active material of a manganese battery or an alkaline manganese battery. The ultimate object is to improve the battery performance of an alkaline manganese battery.

[Means for Solving the Problems] The above object of the present invention is achieved by adding a reducing agent or a nonionic surfactant to an electrolytic solution in an electrolytic step of producing electrolytic manganese dioxide.

That is, the method for producing electrolytic manganese dioxide of the present invention comprises:
In producing electrolytic manganese dioxide using manganese sulfate and a sulfuric acid solution as an electrolytic solution, a reducing agent or a nonionic surfactant is added to the electrolytic solution.

In the production method of the present invention, a solution of manganese sulfate and sulfuric acid is used as the electrolytic solution. The manganese concentration in this electrolyte is generally 20 to 60 g / l, and the sulfuric acid concentration is generally 30 to 90 g / l. As the electrodes, titanium or the like is used for the anode, and carbon or the like is used for the cathode.

The electrolysis conditions of this electrolytic manganese dioxide are usually
The reaction is performed at a bath temperature of 90 to 100 ° C. and a current density of 50 to 100 A / m ² .

In the production method of the present invention, a reducing agent or a nonionic surfactant is added to the electrolytic solution.

As the reducing agent used here, a compound having an amino group or a carboxyl group as a functional group is preferable,
Specifically, hydrazinium sulfate, aniline, sodium formate and the like are preferably exemplified. Preferred examples of the nonionic surfactant include ethylene glycol and condensates thereof.

As a method of adding the reducing agent and the nonionic surfactant, for example, a method of uniformly adding the replenished manganese sulfate solution from the bottom of the electrolytic cell to the space between the electrode plates and the like are exemplified.

The concentration of the reducing agent and the nonionic surfactant in this electrolytic solution is preferably 0.01 to 3.0 g / l from the viewpoint of the characteristics of the obtained electrolytic manganese dioxide.

In the present invention, it goes without saying that a reducing agent and a nonionic surfactant may be used in combination.

As described above, using the electrolytic manganese dioxide obtained by the production method of the present invention as an anode active material, for example, an AA alkaline manganese battery was prepared and its discharge characteristics were confirmed. As compared with the case where electrolytic manganese dioxide obtained by the conventional production method without adding any ionic surfactant was used as the anode active material, it exhibited excellent discharge characteristics.

[Action] The reason why the discharge characteristics are improved when the electrolytic manganese dioxide obtained by the production method of the present invention is used as an anode active material of an alkaline manganese battery or the like is not clear, but the reduction in the electrolytic solution during electrolysis is not clear. It is presumed that the surfactant and the nonionic surfactant slightly affect the degree of manganese dioxide crystal development.

EXAMPLES Hereinafter, the present invention will be specifically described based on examples and the like.

Example 1 A titanium plate as an anode and a graphite plate as a cathode were alternately suspended in an electrolytic cell having an inner volume of 5 l provided with a heating device.
An electrolytic cell provided with an addition tube for an electrolytic replenisher comprising manganese sulfate, a reducing agent or a nonionic surfactant was provided at the bottom of the electrolytic cell.

The electrolytic replenishing solution was prepared by adding aniline as a reducing agent to a manganese sulfate solution so that the aniline concentration in the electrolytic solution was 0.5 g / l.

While injecting the replenisher into the electrolytic cell, the composition of the electrolytic solution was 40 g / l in manganese concentration and 50 g in sulfuric acid concentration during electrolysis.
/ l and adjust the temperature of the electrolytic bath to 95 ± 1 ℃
To keep, carried out at a current density of 60A / m ^2, was continuously electrolysis for 10 days, taken out anode plate electrolytic manganese dioxide was electrodeposited,
Post-treatment was carried out in a conventional manner.

Next, using 7.8 g of the obtained electrolytic manganese dioxide as an anode active material, battery performance was evaluated using an AA alkaline manganese battery shown in FIG. 1 includes an anode (positive electrode) can 1, an anode (positive electrode) 2, a negative electrode (negative electrode) 3, a separator 4, a sealing body 5, a negative electrode (negative electrode) bottom plate 6, and a negative electrode (negative electrode) current collector 7. , Cap 8, heat-shrinkable resin tube 9, insulating rings 10 and 11, and outer can 12.

Using this alkaline manganese battery, 20 ℃ or -20
A continuous discharge test with a discharge load of 2Ω was carried out at room temperature of 2 ° C.
3 to FIG.

Further, the discharge duration was measured until the battery voltage at a room temperature of 20 ° C. and −20 ° C. of the discharge load 2Ω reached 0.9 V, and the battery voltage at 20 ° C. and −20 ° C. of Comparative Example 1 described below was 0.9 V. Discharge duration to reach 10
The results are shown in Table 1 with an index value of 0.

Examples 2 to 9 The same electrolysis as in Example 1 was performed using the same apparatus as in Example 1 except that the reducing agent or the nonionic surfactant in the electrolytic solution and the concentration were changed as shown in Table 1. After performing continuous electrolysis under the conditions for 10 days, post-treatment was performed in the same manner as in Example 1.

Next, a AA alkaline manganese battery shown in FIG. 1 was prepared in the same manner as in Example 1, and a discharge test was performed using this battery. The discharge duration until the battery voltage reached 0.9 V was measured. The results are shown in Table 1.

Comparative Example 1 Using the same apparatus as in Example 1, except that the reducing agent or the nonionic surfactant solution was not added, the electrolysis was performed continuously for 10 days under the same electrolysis conditions as in Example 1, and then as in Example 1. Post-processing was performed.

Next, an AA alkaline manganese battery as shown in FIG. 1 was prepared in the same manner as in Example 1, and this battery was used for 20 minutes.
A continuous discharge test with a discharge load of 2Ω was conducted at room temperature of -20 ° C or -20 ° C, and the relationship between the obtained battery voltage and the duration of discharge was shown in Figs. Table 1 shows the discharge duration.

As apparent from FIGS. 2 and 3, the alkaline manganese battery of Example 1 has a higher operating voltage (battery) than the alkaline manganese battery of Comparative Example 1 despite the difference in temperature (20 ° C. and −20 ° C.). And the discharge duration was increased. Particularly, the discharge duration at a low temperature (−20 ° C.) could be significantly extended.

Also, as shown in Table 1, room temperature 20 ° C or -20 ° C
In each case, the alkaline manganese batteries of Examples 1 to 5 had an extended discharge duration up to 0.9 V as compared with the alkaline manganese battery of Comparative Example 1 in which no reducing agent or nonionic surfactant was added.

Example 10 Using the same device as in Example 1, continuous electrolysis was performed under the same electrolysis conditions for 10 days, and post-treatment was performed as in Example 1.

Next, a zinc chloride-based R20 type manganese battery based on JIS was prepared using 29.9 g of the obtained manganese dioxide as an anode active material.

Using this battery, a continuous discharge with a discharge load of 2Ω was performed at room temperature of 20 ° C., the discharge duration until the battery voltage reached 0.9 V was measured, and the battery voltage of Comparative Example 2 described later reached 0.9 V. The results are shown in Table 2 in the form of an index with the discharge duration up to 100 as an index.

Examples 11 to 18 Using the same apparatus as in Example 1, except that the reducing agent or nonionic surfactant in the electrolyte and the concentration thereof were changed as shown in Table 2, the same electrolysis as in Example 1 was performed. After performing continuous electrolysis under the conditions for 10 days, post-treatment was performed in the same manner as in Example 1.

Next, an R20-type manganese battery was prepared in the same manner as in Example 10, and a discharge test was performed using this battery to reduce the battery voltage.
Table 2 shows the discharge duration until the voltage reaches 0.9 V.

Comparative Example 2 Using the same apparatus as in Example 1, except that the reducing agent or the nonionic surfactant solution was not added, and under the same electrolysis conditions as in Example 1 for 10 days, the same as in Example 1 was performed. Was post-processed.

Next, an R20-type manganese battery was prepared in the same manner as in Example 10, and a discharge test was performed using this battery to reduce the battery voltage.
Table 2 shows the discharge duration until the voltage reaches 0.9 V.

As shown in Table 2, the manganese batteries of Examples 10 to 18 have a longer discharge duration up to a battery voltage of 0.9 V as compared with the manganese batteries of Comparative Example 2 in which no reducing agent or nonionic surfactant is added. I was able to.

[Effects of the Invention] As described above, when producing an electrolytic manganese dioxide by performing electrolysis using manganese sulfate and a sulfuric acid solution as an electrolytic solution, the production of the present invention in which a reducing agent or a nonionic surfactant is added to the electrolytic solution. By using the electrolytic manganese dioxide obtained by the method as an anode active material of a manganese battery or an alkaline manganese battery, an improvement in discharge voltage and an extension of discharge time can be achieved.

Thus, the fact that the discharge voltage can be improved and the discharge time can be extended is extremely effective from the viewpoint of improving the battery performance of a manganese battery or an alkaline manganese battery.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side sectional view showing an example of an alkaline manganese battery, and FIG. 2 is a graph showing the relationship between the discharge time at 20 ° C. and the battery voltage in Example 1 and Comparative Example 1. FIG. 3 is a graph showing the relationship between the discharge time at −20 ° C. and the battery voltage in Example 1 and Comparative Example 1.

Claims (3)

(57) [Claims] 1. A method for producing electrolytic manganese dioxide for an alkaline manganese battery using manganese sulfate and a sulfuric acid solution as an electrolytic solution, wherein a reducing agent or a nonionic surfactant is added to the electrolytic solution. Manufacturing method of electrolytic manganese dioxide for batteries. 2. The method for producing electrolytic manganese dioxide for an alkaline manganese battery according to claim 1, wherein the reducing agent is a compound having an amino group or a carboxyl group. 3. The method according to claim 1, wherein the nonionic surfactant is ethylene glycol or a condensate thereof.