JPS5814468A - Organic electrolyte battery - Google Patents

Abstract

PURPOSE:To stabilize early voltage in an initial discharge stage and decrease deterioration of discharge voltage and capacity after the high temperature storage of a battery by controlling the amount of oxygen adsorption of cupric oxide. CONSTITUTION:Adsorbed oxygen in cupric oxide is released to 1X10<-4>g atom or less by heating cupric oxide at 500-850 deg.C in air or nitrogen atmosphere, then this cupric oxide is used as a positive active mass. A voltage stabilizing time from start of discharge immediately after a battery is produced is short, and the deterioration of discharge capacity is small even after storage at 60 deg.C. Figure shows that in a positive electrode 1 of a button type battery, a positive black mix obtained by mixing cupric oxide and artificial graphite of a conductive mass is press-molded to form a pellet and the pellet is placed in a stainless steel case 2 and press-molded again to fix in the case 2.

Description

[Detailed description of the invention] The present invention uses cupric oxide (Cub) as a positive electrode active material.

This relates to so-called organic electrolyte batteries that use light metals such as lithium, magnesium, and aluminum as negative electrode active materials and organic electrolytes, and are particularly effective in stabilizing voltage early in the early stages of battery discharge and reducing discharge voltage and capacity deterioration after high-temperature storage. The aim is to improve battery performance.

Conventional batteries using cupric oxide as the positive electrode active material are
It has been considered to have excellent storage stability. However, if it is stored at a high temperature of about 60° C. for a month, a drop in discharge pressure and a deterioration in capacity occur. Such deterioration in performance varies greatly depending on the type of cupric oxide.

In other words, as a method for producing cupric oxide, copper nitrate (Cu (
NO3)2 ) = copper carbonate (Cu CO3) - copper hydroxide (Cu(OH)), acetic acid steel ((0M3Co2)4Cu2
-2H20) thermal decomposition method, metallic copper, cuprous oxide (Cu
A method of directly oxidizing 20) in oxygen or air at high temperature and an electrolytic oxidation method are known, but the degree of deterioration varies depending on the starting materials and manufacturing method.

The cause of such performance deterioration is thought to be that oxygen chemically or physically adsorbed on the surface of cupric oxide oxidizes the organic solvent or initiates polymerization. For example, 1,2-dimethoxyethane is a relatively frequently used organic solvent used in organic electrolyte batteries.

This forms peroxide as shown in the following formula with adsorbed oxygen as mentioned above, and the generated peroxide decomposes into aldehydes and ketones.

It is thought that it becomes an acid.

(0): Represents adsorbed oxygen.

In addition, when discharging a battery immediately after manufacture, there is a tendency, as described above, that the larger the amount of adsorbed acid adsorbed, the longer the time required from the start of discharge until the voltage stabilizes. This is thought to be because the more active adsorbed oxygen reacts before the cupric oxide, which is the positive electrode active material, causes a discharge reaction. Especially when used as a power source for a wristwatch, the time required from the start of battery discharge until the voltage stabilizes is
It is desirable to keep the length as short as possible based on seven points, including the accuracy of the clock.

The present inventors investigated the correlation between the amount of oxygen adsorbed by cupric oxide, the voltage stabilization time from the start of discharge immediately after battery manufacture, and the deterioration of battery performance due to high temperature storage of the battery. By regulating the amount of oxygen adsorbed by cupric
It has been found that the above-mentioned drawbacks can be eliminated.

That is, the present invention is characterized in that the cupric oxide is heat treated in air or in a nitrogen atmosphere at a temperature of SOO to 850°C, and the adsorbed oxygen adsorbed to the cupric oxide is used after 1×10−4. In the following, the present invention will be explained in detail with reference to examples thereof.

The cupric oxide used was obtained by repeating the process of firing cuprous oxide at SOO to 700°C and pulverizing it about 5 times.

The amount of oxygen adsorbed by cupric oxide was determined as follows. Add 2 0.1N potassium iodide aqueous solution to 2F cupric oxide.
Add 0CG, shake well, and leave in a cool, dark place for 1 hour. Here, iodine is liberated as shown in the following formula.

(0)+2KI+H20=2KOH+I2 Next, the absorbance of the sample from which iodine had been released was measured using a spectrophotometer, and quantification was performed using a previously determined Ioshin calibration curve.

Figure 1 shows the button-type battery used in the performance test.

1 is the positive electrode, and a pellet is made by pressure-molding 160 tnf of a positive electrode mixture of 100 parts by weight of cupric oxide and 10 parts by weight of artificial graphite, which is a conductive material, and the pellet is put into a stainless steel case 2 and pressurized again. It is molded and fixed inside the case 2. The size of this positive electrode 1 is 8@911 m1 in diameter. The thickness is 0.56 mm, and the electric capacity is 80 mAh. Reference numeral 3 denotes a negative electrode made by punching out a lithium plate with a thickness of 1.60 mm to a diameter of 5.0 mm, and is press-bonded to a sealing plate 6 made of stainless steel equipped with a gasket 4 made of polypropylene. The positive and negative electrode assemblies described above were stacked on top of each other with a separator 6 made of a nonwoven polypropylene fabric interposed therebetween, and then caulked and sealed to form a battery. The size of this battery is 9.6cm in diameter and 2.6m in height.
It is.

In addition, the electrolyte solution is a mixture of propylene carbonate and 1,2-dimethoxyethane at a volume ratio of 1:2.
A solution containing mol of lithium perchlorate was used.

Next, the amount of adsorbed oxygen after heat treating cupric oxide at various temperatures in air for 6 hours is shown in the following table and Figure 3. 13 at 20°C for batteries immediately after manufacture using
It shows the discharge characteristics when discharged with Ω as a load, and especially shows the early part of the discharge when the voltage stabilizes from the start of the discharge. As is clear from the figure, the larger the amount of adsorbed oxygen, the longer the time required for the voltage to stabilize.

In addition, after storing the above battery at 60°C for 1 month,
Figure 4 shows the characteristics when discharging into a 13Ω load at ℃. It is clear that the performance deterioration due to storage is greater when cupric oxide is used, which has a larger amount of adsorbed oxygen.

In the example, a case was described in which cupric oxide obtained by calcining and pulverizing cuprous oxide was used, but as a result of conducting tests similar to those described above even when the starting materials and manufacturing methods were different,
Although there are variations in the amount of adsorbed oxygen without heat treatment, in any case, when the heat treatment temperature becomes 500°C or higher, the amount of adsorbed oxygen decreases to 1.0×10−' gram atom or less per cupric oxide, and It showed the same tendency as in Figure 2. Note that as the temperature increases, the amount of adsorbed oxygen decreases, but cupric oxide decomposes, so the appropriate heat treatment temperature is SOO~86
At 0°C, the treatment time is 1-6 hours.

In battery tests, as mentioned above, batteries using cupric oxide with a higher amount of adsorbed oxygen took longer to stabilize the voltage from the start of discharge immediately after battery manufacture, and the performance deterioration during storage was greater. .

As is clear from the above results, cupric oxide in which the amount of oxygen adsorbed on cupric oxide has been desorbed to less than 1.0 x 10 gram atoms per y of cupric oxide can be stored at a high temperature similar to the positive electrode active temperature. It can be seen that there is little deterioration in battery performance.

As described above, according to the present invention, an organic electrolyte battery with excellent battery performance can be obtained.

[Brief explanation of the drawing]

Figure 1 is a partially cross-sectional side view of the button-shaped battery of the example, Figure 2 is a diagram showing the relationship between the heat treatment temperature of cupric oxide and the amount of adsorbed oxygen, and Figure 3 is the discharge immediately after battery manufacture. FIG. 4 is a diagram showing the discharge characteristics after the battery has been stored. 1...Positive electrode, 3...Negative electrode, 6...
... Senokureta. Fig. 1 Fig. 2 Twisting process

Claims (1)

[Scope of Claims] A positive electrode having cupric oxide as an active material, a negative electrode having a light metal as an active material, and an organic electrolyte, wherein the amount of oxygen adsorbed by the cupric oxide is per cupric oxide. 4. An organic electrolyte battery characterized by having a particle size of 1.0×10 gram atoms or less.