JPS5868869A - Nonaqueous battery - Google Patents

Abstract

PURPOSE:To improve a voltage drop in the initial stage of discharge after storage without decreasing flat discharge voltage (operating voltage) by mixing a metal compound which is rechargeable with lithium in a nonaqueous electrolyte positive electrode. CONSTITUTION:In a nonaqueous battery using lithium as a negative active mass and cupric oxide as a positive active mass, a metal compound, such as vanadium pentaoxide, titanium disulfide, molybdenum trioxide, which is rechargeable with lithium in a nonaqueous electrolyte is allowed to coexist in a positive electrode. Vanadium oxide or titanium sulfide is discharged preferentially to cupric dioxide in predischarge after assembling, and a discharge product indicating as LixV2O5 and LiyTiS2 respectively is formed in the positive electrode. Since these discharge products have less noble potential than that of cupric oxide, the closed circuit voltage of the battery mixed with these metal compound is lowered compared with that of the positive electrode using cupric oxide alone, and since dissolution of copper is suppressed, a voltage drop in the initial stage of discharge after storage is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a nonaqueous electrolyte battery that uses lithium as a negative electrode active material and cupric oxide as a positive electrode active material.

(Cupric oxide has an extremely large capacity as an active material, is relatively cheap, and is an abundant resource, so it is attracting attention as a positive electrode material for non-aqueous electrolyte batteries. In particular, cupric oxide-lithium Since the operating voltage of the nonaqueous electrolyte battery in the system is about 1.6 V, it has the advantage of being easily compatible with silver oxide batteries and mercury type 111!, which are commonly used as power sources for electronic devices.

On the other hand, a drawback is that a sudden drop in the initial discharge voltage after storage is observed. (See Figure 1 A).

The cause of this is Cu o/L i in one column in the nonaqueous electrolyte.
The equilibrium potential of is 2.32 V, but actually one is 6.2 V.
It shows an open circuit voltage of about V. Therefore, one positive electrode (oxidized second
The main factor is considered to be that the copper in the copper (copper) is dissolved electrically and deposited as metallic copper on the lithium electrode surface 1h1 to form a passive film. However, since this passive film is destroyed by discharge, it returns to the operating potential as the discharge progresses after long-term storage.

In order to improve the drop in the initial discharge voltage after storage, a metal or a compound thereof having a potential lower than cupric oxide, such as zinc or tin, is mixed in the positive electrode to increase the open circuit voltage. There are proposals to lower it. Although method 1 suppressed the drop in the initial discharge voltage after storage, it was found that the discharge flat voltage (operating voltage) decreased slightly (see Figure 1).

The reason for this is that a local battery is formed between the added metal compound and cupric oxide, which is the positive electrode active material, and the metal ions in the metal compound dissolve and precipitate on the negative electrode surface, increasing the internal resistance. it is conceivable that.

The present invention is intended to solve the above-mentioned problems, and its gist is to use a metal compound, such as vanadium pentoxide, which can undergo a charge/discharge reaction with lithium in a positive fL!l!IC non-aqueous electrolyte. There is one point in mixing titanium disulfide, molybdenum trioxide, etc.

Embodiment 1 of the present invention will be described in detail below.

Example 1 Commercially available special grade cupric oxide powder IC vanadium pentoxide (V2
Add 10% by weight of 05J and mix to obtain 0.2% of this mixed powder.
5 g was weighed and molded under pressure at a pressure of 3 tons/j into a current collector ring with a diameter of 10.8 square meters, and then fired at 850° C. to form a positive electrode.

The negative electrode used was a lithium rolled plate with a predetermined thickness punched out with a diameter of 8.6 M1, and the electrolyte was prepared by dissolving 1 molar concentration of lithium perchlorate in propylene. The separator is polypropylene non-4a cloth Q, and the battery size is 1 in diameter.
Theoretical capacity is 150 mAH with 1.5 m and 1φ diameter 3.4 mm.
Atsufko.

And battery assembly? , 1 to Ω “C5 o’clock 111th” b1
M discharge was performed to obtain a completed battery IAI.

Example 2 Commercially available special grade cupric oxide powder 1 titanium disulfide (rIS2
Add 15% J by weight and mix, and make 0.25g of this mixed powder.
RB, 15, which was pressure molded at a pressure of 6 tons/clr in one block ring with a diameter of 1 [], 8-#.
A positive electrode is prepared by drying at 1-C.

Hereinafter, as in Example 1, 1 electric train/11! Assemble and perform preliminary discharge with IKΩ and charge/discharge i'll! It was set as 1B+.

Example 3 Commercially available special grade molybdenum trioxide (MOOJ b Og)
n-butyl lithium in a solution of 15% hexane solution 1e
LizMoOA was adjusted by gradually adding 1 part of this powder, and this powder obtained by mouth filtration, washing, and drying was added to cupric oxide powder that had been heat-treated at 850°C in advance and mixed with 15% r. The mixed powder was pressure-molded using a current collector ring 11 with a diameter of 10.8 W at a pressure of 6 tons/al, and then dried at 150° C. to form a positive electrode.

The IC battery is assembled and completed in the same manner as in Example 1.
shall be. However, in this embodiment, since the positive electrode is mixed in the form of a discharge product of molybdenum trioxide and lithium at the time of assembling the upper cell, there is no need to perform preliminary discharge.

The table below shows the expiry value after storing the battery at 60°C for one month after assembly, and it can be seen that the open circuit voltage has been suppressed, and the closed circuit voltage and internal resistance have significantly improved by 1.

The table and Figure 1 show the discharge characteristics of various types of batteries with one Ω load placed on them after battery assembly and storage at 60°C for one month.
It can be seen that the phenomenon of drop in the initial discharge pressure is improved and the operating voltage is reduced by 1j.

The comparative battery (A) is an electric oil using a positive electrode containing a metal having a potential lower than cupric oxide, such as zinc or tin, or a compound thereof, and a comparative Tli 7111! Iro 1 is a battery containing a cupric oxide positive electrode with additive 1.

Considering the effects of the present invention 1. In the battery IAIt131, vanadium oxide or titanium sulfide is released preferentially over cupric oxide due to preliminary discharge after battery assembly, and the discharge products represented by LixVzOs and LiyTiSz, respectively, become the positive electrode. formed inside. Also, batteries (0 burns)
At the time of assembling heavy oil, molybdenum dioxide and lithium discharge product C, LizMoOA, is mixed in the positive electrode.

And these discharge products are qrl than cupric oxide.
Since it has a potential, it is 1M 2 + 1! compared to the case of a positive electrode using cupric oxide alone. Since the open circuit voltage of the battery can be lowered and the dissolution of copper can be suppressed, the phenomenon of drop in voltage at the initial stage of discharge after storage can be improved.

In addition, 11:, abrasion discharge products mixed in the pole (LixV
2O5, Liy'l'iSz, LizMoOg)
A local cell is formed between the and cupric oxide and lithium ions are released from the discharge products, whereas the comparative cell (
b) Unlike the case of 1j metal ions such as zinc and tin in I, even if they are deposited on the negative electrode, they do not form a passive film and do not cause the inconvenience of lowering the operating voltage. .

As for the amount of addition of TJ metal compound capable of charge/discharge reaction with lithium, if one long edge is mixed, the discharge voltage curve will change to two stages.
C10-1 for cupric oxide active materials as there is a concern that
Approximately 5% by weight is appropriate.

As described in detail below, the present invention relates to a nonaqueous electrolyte battery 1 in which lithium is used as a negative electrode active material and cupric oxide is used as a positive electrode active material. By mixing lithium and a RL metal compound capable of charge/discharge reaction in the first stage of storage, the discharge flat voltage (operating voltage) is lowered, and the phenomenon of drop in the initial discharge voltage after storage is improved. Therefore, its industrial value is extremely large.

[Brief explanation of drawings]

Fig. 1 is a comparison diagram of the discharge characteristics of the battery of the present invention and the comparative battery after storage for 1 month at 60"C. battery.

Claims (1)

[Claims] ■ A negative electrode containing lithium as an active material, a non-aqueous electrolyte, and a positive electrode containing cupric oxide as an active material; A non-aqueous electrolyte battery in which lithium and a metal compound capable of charging and discharging reactions are mixed together. (2) The nonaqueous electrolyte battery according to claim 0, wherein the metal compound is vanadium oxide, titanium sulfide, or molybdenum oxide.