JPS58152376A - Organic electrolyte battery - Google Patents

Abstract

PURPOSE:To increase the quantity of the electric-discharge electricity of an organic solvent battery by using iron disulfide as an active material for the positive electrode, and washing said iron disulfide with hydrochloric acid so as to dissolve and remove impurities such as iron sulfide, iron metal and iron oxide contained in said iron disulfide. CONSTITUTION:In an organic electrolyte battery, a negative electrode 7 is prepared by using a light metal such a lithium as a negative active material, a positive electrode 1 is prepared by using as a positive active material, iron disulfide which is washed with hydrochloric acid so as to dissolve and remove impurities such as iron sulfide, iron metal and iron oxide contained in it, and electrolyte is prepared by dissolving lithium perchlorate in a mixture solvent consisting of propylene carbonate and 1,3-dioxysolane. In addition, such an organic electrolyte battery is constituted by the combination of a separator 4, a positive can 3, a negative can 5 and a gasket 8. Therefore, any reduction of the quantity of the electric-discharge electricity of the battery which might be caused due to impurities which might exist in the above iron disulfide can be prevented. Consequently, the quantity of the electric-discharge electricity of the battery can be increased, and the closed-circuit voltage of the battery in the midst of electric discharge can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in organic electrolyte batteries that use light metals such as lithium as a negative electrode active material and iron disulfide as a type of positive electrode active material. The purpose is to improve the closed circuit voltage.

Organic electrolyte batteries that use iron sulfide as the positive electrode active material use manganese dioxide or carbon fluoride as the positive electrode active material. Compared to organic electrolyte batteries used in ``Energy density'' is expected to develop in the future.

Among iron sulfates, iron disulfide (FeS2) (d:
It has a large electric capacity per unit weight, and is considered to be a particularly suitable positive electrode active material from the viewpoint of high capacity.

1.7 or 1 ~ In addition to FeS2, commercially available iron disulfide contains Fe S -, Fe U, 95 S -, Fe O,
Impurities such as iron sulfide such as 88S, metallic iron, and iron oxide are present in the mixture. In particular, if iron oxides are present, the internal resistance will be high, the amount of discharged electricity will be significantly reduced, and the closed circuit voltage during discharge will also be reduced. By washing commercially available iron disulfide with hydrochloric acid, metallic iron, iron oxide,
Furthermore, Fe S , Fe o, s other than FeS2
By dissolving and removing iron sulfides such as S, Fe o, and ss S, and refining iron disulfide before using it as a positive electrode active material, emissions caused by mixed impurities can be reduced by reducing the amount of electricity and decreasing the closed circuit voltage. The present invention provides a battery that prevents this, has a large amount of discharged electricity, and has a high closed circuit voltage during discharge.

That is, the present invention provides an organic electrolyte battery having a negative electrode using a light metal such as lithium as a negative electrode active material, and a positive electrode using iron disulfide as a positive electrode active material, wherein the iron disulfide is washed with hydrochloric acid. The present invention relates to an organic electrolyte battery characterized by:

The hydrochloric acid washing treatment of iron disulfide is carried out by immersing powdered iron disulfide in hydrochloric acid having a concentration of about 1 to 6 N, for example. At that time, heating and stirring may be performed. Since iron disulfide does not dissolve in hydrochloric acid, the above-mentioned hydrochloric acid washing treatment removes iron oxides, metallic iron, FeS, etc. mixed in iron disulfide.
Iron sulfides other than iron disulfide such as FeO, 95S, Feg, BBS, etc. are dissolved and removed, and the iron disulfide is
6ru.

Examples of light metals used as negative electrode active materials in the present invention include lithium, sodium, magnesium, and aluminum. The electrolyte may be a solvent such as propylene carbonate, γ-butyrolactone, tetrahydrofuran, 1,2-dimethoxyethane, dioxolane, etc., or a mixed solvent of two or more, and lithium perchlorate, lithium hora sulfide, etc. It is preferable to use one in which an electrolyte is dissolved.

In the present invention, using iron disulfide as one type of positive electrode active material refers to cases in which iron disulfide alone is used as a positive electrode active material, and cases in which iron disulfide is used in combination with other positive electrode active materials such as copper oxide to form a positive electrode active material. This refers to the case where it is used as As the copper oxide, cuprous oxide, cupric oxide, etc. are used, and when used together with iron disulfide, the ratio of iron disulfide and oxidized steel is in the range of 75:25 to 25Nia5 by weight. is preferred.

Next, the present invention will be explained with reference to Examples.

Commercially available powdered iron disulfide was placed in a large excess of 3N hydrochloric acid, and heated at about 60° CVc for 1 hour while stirring. After cooling, it was filtered and washed with water. After washing with water, it was vacuum dried at 100°C for 4 hours. The removal of impurities is based on the fact that only a peak of iron disulfide is detected in X-ray diffraction analysis of the treated iron disulfide, and that no hydrogen sulfide is generated when the treated iron disulfide is immersed in 6N hydrochloric acid. This was confirmed by the fact that no iron was detected in the hydrochloric acid solution.

Next, a mixture is prepared by mixing with ferric disulfate f cupric oxide (Cub'), acetylene black, polytetrafluoroethylene, etc. which have been washed with hydrochloric acid as described above.

The mixture composition is 40 parts iron disulfide (parts by weight, the same applies below)
, 40 parts of cupric oxide, 15 parts of acetylene black, and 2 parts of polytetrafluoroethylene. This mixture is filled into a mold equipped with a stainless steel annular pedestal, and Q
, 5t/cm2, and this was used as a positive electrode.

The above positive electrode, a negative electrode made of a lithium plate with a diameter of 6.8 mg and a thickness of 1.3 M, propylene carbonate and 1.3-
Using an electrolytic solution in which 1 mol/l of lithium perchlorate was dissolved in a mixed solvent with a volume ratio of 1=1 with dioxolane, an electrolyte with a diameter of 9.5 ww and a height of 8.611 mm was constructed as shown in Figure 1. An organic electrolyte battery was assembled using a conventional method. In FIG. 1, (1) is the above-mentioned positive electrode, (2) is the above-mentioned annular pedestal, and (3) is an iron positive electrode can whose outer surface is nickel-plated. (4) is a separator made of polypropylene nonwoven fabric, (5) is a negative electrode can made of a nickel-stainless steel clad plate, and a stainless steel mesh (6) is spot-welded to the inner surface of this negative electrode can (5). Tangent line (6
) The negative electrode (7) is crimped onto the portion. and(
8) is an annular gasket made of polypropylene.

FIG. 2 shows the discharge characteristics when battery A having the above structure and a battery Bf using commercially available iron disulfide without being washed with hydrochloric acid were continuously discharged at 20° C. and a load of 15 Ω. At 40% discharge of these batteries A and B and 8 ()
The closed circuit voltage after discharging for 0.1 second at -10°C and load 2 at Ω at the time of inter-discharge is shown in Table 1 below. Note that Battery B is an organic electrolyte battery having the same structure as Battery A except that the iron disulfide was not washed with hydrochloric acid.

Table 1 As shown in FIG. 2 and Table 1, the battery of the present invention discharged a larger amount of N electricity than the conventional battery B, and also had a higher closed-circuit voltage during discharge. In the case of conventional battery B, the discharge voltage begins to drop after approximately 250 hours of discharge, resulting in a decrease in the amount of discharged electricity and a decrease in the closed circuit voltage during discharge. This is thought to be due to impurities mixed in iron disulfide.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the organic electrolyte battery of the present invention, and FIG. 2 is a discharge characteristic diagram of the organic electrolyte battery of the present invention and a conventional organic electrolyte battery. (1)...Positive electrode, (7)...Negative electrode Patent applicant
Hitachi Maxell, Ltd. Figure 1 Figure 2 0 200 400 600 800 Discharge time (h) -392

Claims (1)

[Claims] 1. A negative electrode using a light metal such as lithium as a negative electrode active material,
1. An organic electrolyte battery comprising a positive electrode containing iron disulfide as one type of positive electrode active material, wherein the iron disulfide is washed with hydrochloric acid.