JPH03223483A - Production of electrolytic manganese dioxide - Google Patents

Abstract

PURPOSE:To produce the electrolytic manganese dioxide having high performance by using a soln. of manganese sulfate and sulfuric acid as an electrolyte and adding a reducing agent or nonionic surfactant into the electrolyte. CONSTITUTION:An electrolysis is effected by using the manganese sulfate and sulfuric acid soln. as the electrolyte to produce the electrolytic manganese dioxide. The reducing agent and nonionic surfactant are added at about 0.01 to 3.0g/l into this electrolyte. Hydradinium sulfate having an amino group or carboxyl group, and aniline, etc., are used as the reducing agent and ethylene glycol and the condensation product thereof, etc., are used as the nonionic surfactant. The discharge voltage of a manganese battery is improved and the discharge time thereof is prolonged if this electrolytic manganese dioxide is used as the anodic active material of this battery.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application 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 a positive electrode active material for manganese batteries or alkaline manganese batteries, and has the advantages of excellent storage stability and low cost.

In particular, alkaline manganese batteries that use manganese dioxide as the anode active material have excellent discharge performance under heavy loads, and are used in automatic winder strobes for cameras and portable tape recorders, and demand has been rapidly increasing in recent years. It's coming.

However, when using alkaline manganese batteries, there is a problem that the discharge potential gradually decreases, making them difficult to use. Batteries are required.

On the other hand, manganese batteries have a problem of poor discharge performance under heavy loads.

In view of the above-mentioned circumstances, an object of the present invention is to provide a manufacturing method that can achieve high performance of electrolytic manganese dioxide used as an anode active material of manganese batteries or alkaline manganese batteries, and furthermore, The ultimate objective is to improve the performance of alkaline manganese batteries.

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

That is, the method for producing electrolytic manganese dioxide of the present invention involves adding a reducing agent or a nonionic surfactant to the electrolytic solution when electrolyzing manganese sulfate and a sulfuric acid solution as an electrolytic solution to produce electrolytic manganese dioxide. This is a characteristic feature.

In the production method of the present invention, a solution of manganese sulfate and sulfuric acid is used as the electrolyte. The manganese concentration in this electrolyte is generally 20 to Bog/J, and the sulfuric acid concentration is generally 30 to 90 g/J. In addition, as an electrode, titanium etc. are used for the anode.
Carbon or the like is used for the cathode.

The electrolysis conditions for this electrolytic manganese dioxide are usually a bath temperature of 90 to 100 DEG C. and a current density of 50 to ■ooA/TIt.

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

The reducing agent used here is preferably a compound having an amino group or a carboxyl group as a functional group, and specific examples thereof include hydrazinium sulfate, aniline, sodium formate, and the like.

Preferable examples of nonionic surfactants include ethylene glycol and condensates thereof.

Examples of the method for adding the reducing agent and nonionic surfactant include a method in which they are added uniformly from the bottom of the electrolytic cell between the electrode plates together with a supplementary manganese sulfate solution.

The concentration of the reducing agent and nonionic surfactant in this electrolytic solution is preferably 0.01 to 3.0 g/J in view of the properties of the electrolytic manganese dioxide obtained.

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

As described above, when a single-cell alkaline manganese battery, for example, was created using the electrolytic manganese dioxide obtained by the production method of the present invention as an anode active material, and its discharge characteristics were confirmed, it was found that there was no reducing agent or non-reducing agent in the electrolyte. It showed superior discharge characteristics compared to the case where electrolytic manganese dioxide obtained by the conventional manufacturing method without adding any ionic surfactant was used as the anode active material.

[Function] It is not clear why the discharge characteristics are improved when the electrolytic manganese dioxide obtained by the production method of the present invention is used as the positive electrode active material of alkaline manganese batteries, etc., but during electrolysis, the It is presumed that the reducing agent and nonionic surfactant subtly affect the degree of crystal development of manganese dioxide.

[Example] Hereinafter, the present invention will be specifically explained 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 with an internal volume of 5 mm equipped with a heating device,
An electrolytic cell with an addition tube for an electrolytic replenishment solution consisting of manganese sulfate, a reducing agent, or a nonionic surfactant at the bottom was used.

The electrolytic replenishment solution is made by adding aniline as a reducing agent to a manganese sulfate solution, and the aniline concentration in the electrolyte is 0.5 g/J.
, was adjusted so that

While injecting this replenishment solution into the electrolytic bath, the composition of the electrolytic solution was adjusted to have a manganese concentration of 40 g/J1 sulfuric acid concentration of 50 g/J during electrolysis, and the temperature of the electrolytic bath was maintained at 95 ± 1°C during electrolysis. After continuous electrolysis for 10 days at a current density of BOA/TIt, the anode plate on which electrolytic manganese dioxide was electrodeposited was taken out and subjected to a conventional post-treatment.

Next, 7.8 g of the obtained electrolytic manganese dioxide was used as an anode active material, and battery performance was evaluated using a single-cell alkaline manganese battery shown in FIG. The alkaline manganese battery shown in FIG. , a cap 8ζ, a heat-shrinkable resin tube 9, an insulating ring 10, 11, and an outer can 12.

Using this alkaline manganese battery, 20°C or -20°C
A continuous discharge test was conducted at a room temperature of 0° C. with a discharge load of 2Ω, and the relationship between the obtained battery voltage and discharge duration is shown in FIGS. 2 and 3.

Also, the room temperature with a discharge load of 2Ω is 20"C and -2fl'
The discharge duration until the battery voltage reached 0.9V at C was measured, and the discharge duration until the battery voltage reached 0.9V at 20°C and -20°C in Comparative Example 1, which will be described later, was determined as 100 and 100, respectively. The results are shown in Table 1.

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

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

Comparative Example 1 Using the same equipment as in Example 1, continuous electrolysis was performed for 10 days under the same electrolytic conditions as in Example 1 except that no reducing agent or nonionic surfactant solution was added, and then electrolysis was carried out in the same manner as in Example 1. Post-processing was performed.

Next, a single bead alkaline manganese battery shown in FIG. 1 was prepared in the same manner as in Example 1, and this battery was used to
℃ or -20℃, a continuous discharge test with a discharge load of 2Ω was carried out, and the relationship between the obtained battery voltage and discharge duration is shown in Figures 2 and 3, and until the battery voltage reached 0.9V. The discharge duration is shown in Table 1.

As is clear from FIGS. 2 and 3, the alkaline manganese battery of Example 1 has the following characteristics compared to the alkaline manganese battery of Comparative Example 1:
Despite the temperature difference (20°C and -20'C), it shows a high operating voltage (battery voltage) and extended discharge duration, especially at low temperature (-20'C), which significantly extends the discharge duration. I was able to do it.

In addition, as shown in Table 1, the room temperature is 20°C or 20°C.
In any case, the alkaline manganese batteries of Examples 1 to 5 had a lower voltage of 0.9V compared to the alkaline manganese battery of Comparative Example 1 in which no reducing agent or nonionic surfactant was added.
The discharge duration has been extended.

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

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

Using this battery, continuous discharge was performed at a discharge load of 2Ω at a room temperature of 20°C, and the discharge duration until the battery voltage reached 0.9V was measured.
The results are shown in Table 2, expressed as an index with the discharge duration until reaching 9V set as 100.

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

Next, an R2D type manganese battery was prepared in the same manner as in Example 10, and a discharge test was conducted using this battery. Table 2 shows the discharge duration until the battery voltage reached 0.9V.

Comparative Example 2 Using the same equipment as in Example 1, continuous electrolysis was performed for 10 days under the same electrolytic conditions as in Example 1, except that no reducing agent or nonionic surfactant solution was added, and then the same as in Example 1 was used. Post-processing was performed.

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

As shown in Table 2, the manganese battery of Examples 10-18 has a longer discharge duration up to a battery voltage of 0.9 V than the manganese battery of Comparative Example 2 in which no reducing agent or nonionic surfactant is added. I was able to extend it.

Table 1 [Effects of the Invention] As explained above, when electrolysis is performed using manganese sulfate and a sulfuric acid solution as an electrolyte to produce electrolytic manganese dioxide, a reducing agent or a nonionic surfactant is added to the electrolyte. By using the electrolytic manganese dioxide obtained by the production method of the present invention as a positive electrode 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.

The ability to improve the discharge voltage and extend the discharge time in this way is extremely effective from the standpoint of improving the battery performance of manganese batteries or alkaline manganese batteries.

[Brief explanation of drawings]

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

Claims (1)

[Claims] 1. Electrolytic manganese dioxide characterized by adding a reducing agent or a nonionic surfactant to the electrolytic solution when producing electrolytic manganese dioxide using manganese sulfate and a sulfuric acid solution as an electrolytic solution. manufacturing method. 2. The method for producing electrolytic manganese dioxide according to claim 1, wherein the reducing agent is a compound having an amino group or a carboxyl group. 3. The method for producing electrolytic manganese dioxide according to claim 1, wherein the nonionic surfactant is ethylene glycol and a condensate thereof.