JPS61173455A - Nonaqueous electrolyte battery - Google Patents

Abstract

PURPOSE:To improve storage performance of a nonaqueous electrolyte battery by adding iron sulfide and cupric sulfide to a positive electrode using cupric oxide as active material. CONSTITUTION:When iron sulfide and cupric sulfide are added to a positive electrode 1 using cupric oxide as active material, the decomposition of cupric oxide is retarded and parts of iron sulfide and cupric sulfide are dissolved and the generated sulfur deposits on the surface of a lithium negative electrode 2 as a film. The film deposited prevents the surface of the lithium negative electrode from the deposition of metallic copper. The adding amount of the binary system of iron sulfide and cupric sulfide is preferably limited to 5-40wt% based on the weight of positive active material.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application The present invention relates to a non-aqueous electrolyte battery using cupric oxide as a positive electrode active material.

(b) Conventional technology A non-aqueous electrolyte battery using cupric oxide as a positive electrode active material and lithium or a lithium alloy as a negative electrode active material is, for example,
It is known from Japanese Patent No. 9-33935, and since its battery voltage is about 1.4 V, it has the advantage that it can be used interchangeably with silver oxide batteries and mercury batteries that are commonly used as power sources for electronic devices.

However, when this type of battery is stored, the cupric oxide as the positive electrode active material decomposes and metal steel dissolves in the electrolyte, and this metal steel precipitates on the surface of the lithium negative electrode, increasing the internal resistance and damaging the battery. There is a problem that the discharge capacity of the battery decreases.

(c) Problems to be Solved by the Invention The purpose of the present invention is to improve the storage characteristics of a nonaqueous electrolyte battery that uses cupric oxide as a positive electrode active material and lithium or a lithium alloy as a negative electrode active material. It is something.

(d) Means for Solving the Problems The present invention resides in a non-aqueous electrolyte battery characterized in that iron sulfide and cupric sulfide are added to a positive electrode that uses oxidized second steel as an active material.

The amount of the two-component additive of iron sulfide and cupric sulfide is preferably in the range of 5 to 40% by weight based on the amount of the positive electrode active material.

(E) Function When iron sulfide and cupric sulfide are added to a positive electrode containing cupric oxide as an active material, the decomposition of cupric oxide is suppressed, and
Sulfur produced by dissolving a portion of iron sulfide and cupric sulfide is deposited as a film on the surface of the lithium negative electrode, and it is possible to suppress the deposition of metallic copper on the surface of the lithium negative electrode.

Kube) Example Examples of the present invention will be described in detail below.

85% by weight of a positive electrode mixture made by mixing 15% by weight of iron sulfide and 15% by weight of cupric sulfide with respect to commercially available special grade cupric oxide;
After adding and thoroughly mixing 10% by weight of acetylene black and graphite as conductive agents and 5% by weight of fluororesin powder as a binder, this mixture was pressure-molded at a pressure of about 2 tons/aT12 to form a diameter of 15. , Om, thickness 1.1111ff+
A molded body is obtained, and this molded body is heat-treated at a temperature of 200 to 300°C to form a positive electrode.

The negative electrode is made by rolling a lithium plate to a thickness of about 0.6 m, and this lithium rolled plate is made into a lithium plate with a diameter of 15. On! It is punched out in the size l. ! The solution was made by dissolving 1 mole of lithium perchlorate in a mixed solvent of propylene carbonate and 1.2 dimethoxyethane, and was used to impregnate a separator to form a battery with a diameter of 20.0 cm and a thickness of 2.5 m. (A) was created.

Figure 1 shows a longitudinal cross-sectional view of the battery of the present invention, in which (1) is a positive electrode with cupric oxide as an active material and iron sulfide and cupric sulfide are added, (2) is a lithium negative electrode, and 3) is an electrolytic This is a separator impregnated with liquid. Further, (4) is a positive electrode ring, (5) is a positive electrode current collector, (6) is a negative electrode current collector, (7) and (8) are positive and negative electrode outer cans, and (9) is an insulating backing.

Next, in order to examine the superiority of the battery of the present invention, a comparative battery (B) was prepared which was the same as the battery of the present invention except that iron sulfide and cupric sulfide were not added to the cupric oxide positive electrode.

FIG. 2 shows the change in internal resistance over time when these batteries were stored at a temperature of 60° C. and a humidity of 90%.

In addition, Figure 3 shows the discharge characteristics of these batteries at 20°C and 5.6kQ constant load discharge, where the solid line shows the initial characteristics and the broken line shows the discharge characteristics after battery assembly at a temperature of 60°C and a humidity of 90% for 20 days. The discharge characteristics after storage are shown.

From FIGS. 2 and 3, the present invention battery (A> is the comparative battery (B)
), it can be seen that the storage characteristics are improved, especially under high temperature and high humidity conditions.

Considering the reason for this, in the battery of the present invention, when iron sulfide and cupric sulfide are added to the positive electrode that uses oxidized flat steel as an active material, the decomposition of cupric oxide is suppressed, and iron sulfide and cupric sulfide The sulfur produced when a part of the copper dissolves is deposited as a film on the surface of the lithium negative electrode, so even if the cupric oxide decomposes and metallic copper dissolves in the electrolyte, metallic steel will not form on the surface of the lithium negative electrode. It is thought that since precipitation is suppressed, an increase in internal resistance is suppressed and storage characteristics are improved.

Note that the sulfur film is easily destroyed by discharge, so it does not adversely affect the discharge characteristics.

(g) Effects of the invention As mentioned above, in a non-aqueous electrolyte battery equipped with a positive electrode containing cupric oxide as an active material, by adding iron sulfide and ferric sulfide steel to the positive electrode, excellent storage characteristics can be achieved. If a non-aqueous electrolyte battery can be obtained, its industrial value is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the battery of the present invention, FIG. 2 is a diagram showing the relationship between internal resistance and storage period, and FIG. 3 is a diagram showing the discharge characteristics of the battery. (1)...Positive electrode, (2)...Negative electrode, (3)...Separator, (4)...Positive electrode ring, (5)...Positive electrode current collector, (6)... Negative electrode current collector, (7) (8)...
Positive and negative electrode outer can, (9)...Insulating backing, (A)
...Battery of the present invention, (B)...Comparison battery.

Claims (1)

[Claims] 1. A negative electrode using lithium or lithium alloy as an active material,
1. A non-aqueous electrolyte battery comprising a non-aqueous electrolyte and a positive electrode containing cupric oxide as an active material, wherein iron sulfide and cupric sulfide are added to the positive electrode.