JPH0642377B2 - New battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION zinc iodide, metal iodides such as cadmium iodide (MI _n
Can be used as an electrolyte to fabricate a secondary battery, that is, a storage battery (hereinafter referred to as a storage battery) (Japanese Patent Laid-Open No. Sho.
57-15369, JP-A-57-197759, Inorg.Chim.Acta, 86 , L47 (1
984), Hyundai Kagaku, 165 , 48 (December 1984), Chem. Abstr., 7
3 , P20869a etc.). When this storage battery is charged, the following reactions occur at both the positive and negative electrodes.

Positive electrode Negative electrode M ^{n +} + ne ⁻ → M (2) During discharge, a reaction reverse to the above reaction occurs.

By the way, a part of I ₂ generated on the positive electrode side by the reaction of formula (1) during charging reacts with the remaining I ⁻ ion to form a polyiodide ion such as I ₃ ⁻ . Then, the polyiodide ion reacts with the metal M that is the negative electrode active material (for example, Z _n
+ I ₃ ^- will not become a) would if occur self-discharge good performance battery ^{_{- → Z n I 2 + I}} . Therefore, in order to suppress such self-discharge, in the above-mentioned storage battery, a cation exchange membrane is placed between the positive electrode and the negative electrode to separate the positive electrode chamber and the negative electrode chamber and prevent polyiodide ions from reaching the negative electrode. (See Contemporary Chemistry, 165 , 48 (December 1984 issue), etc.). Thus, I ₂ generated on the positive electrode side by charging without thereby moved to the anode side becomes polyiodide ions, whereas the metal cations, such as Z _n ⁺² present in positive electrode chamber (M ^{n +} ) can be transferred to the negative electrode chamber through the cation exchange membrane and can participate in the charging reaction. During discharging moves to the positive electrode chamber from the negative electrode chamber through the M ^{n +} cation exchange membranes produced in negative electrode chamber by a reverse reaction of equation (2), was formed in the positive electrode chamber by a reverse reaction of equation (1) I ^- It gives the solution of MI _n in the positive electrode chamber together. Accordingly, in such a type of battery, M ^{n +} and I of MI _n present in positive electrode chamber ^- are involved in substantial charge and discharge reaction, the MI _n in capacity of the storage battery is mainly positive electrode chamber Determined by abundance. For this reason, in the storage battery of this type, it devised to present effectively the large amount of MI _n is important in positive electrode chamber. One of such measures is to increase the concentration of MI _n in the electrolyte solution, but in addition, it is effective by using a porous chamber material as a positive electrode agent and soaking the solution in which MI _n is dissolved. A lot of M
Devising such as allowed to exist I _n in the positive electrode chamber is considered. However, even when such a measure is taken, in order to reduce the internal resistance of the storage battery and obtain a storage battery with higher efficiency, it is desirable that the positive electrode has an electric conductivity above a certain level. The present invention has been made from these points of view, and if a conductive porous material is used as the positive electrode material, as is clear from the principle, a storage battery with good performance using the dissociated metal iodide as the electrolyte is obtained. can get. A powerful method for obtaining a porous substance having electrical conductivity is to mold a mixture of a fine powder substance and carbon powder. When such a method is used in the present invention, the fine particulate material to be molded together with the carbon powder may be, for example, a polymer compound such as polyamide, clay, alumina, etc., which can form a porous material effectively in principle. Good. However, if possible, it is desirable that the substance has the ability to retain iodine (see the above-mentioned literature), such as polyamide, and from the viewpoint of the mechanical strength of the obtained porous substance, that porous substance is added. It is desired to be molded by a molding method such as pressure or sintering and to have sufficient mechanical strength. For example, polyamides such as nylon-6, which can be sintered in the state of a mixture with carbon powder (refer to the Spacey Chemical Co., Ltd. (Hachioji City, Tokyo) pamphlet), are typical ones, and a mixture of clay and carbon powder is also available. It is expected that an electrically conductive porous material with good performance can be obtained by baking the product under an inert gas or under vacuum. A metal iodide such as zinc iodide or cadmium iodide is suitable as the electrolyte used in the present invention, and a metal corresponding to the metal ion in the metal iodide is used as the negative electrode active material.

Example 1. A powdery nylon-6 and carbon powder (Ketjenblack) were mixed at a weight ratio of 4: 1 and molded by Spacey Chemical Co., Ltd. by a sintering method to form a cylindrical porous material (height: about 29 mm,
A diameter of about 20 mm) was cut out to obtain a flat piece (weight: about 1.1 g) having an area of about 0.70 cm ^{2 and a} thickness of 0.2 mm. The electric conductivity of the porous material was about 3 × 10 ^-2 Scm ^-1 at room temperature, and the apparent specific gravity was about 0.8. The flat piece obtained in this way was
Immersion g of Z _n I ₂ in a solution in water of 10 ml, was absorbed solution 0.20 g. Using the thus obtained porous material impregnated with Z _n I ₂ , the storage battery of FIG. 1 was produced. In this example, as the glass fiber papers 3 and 6 in FIG. 1, GA-100 (area 0.70 cm ² ) manufactured by Toyo Paper Co., Ltd. was used.
impregnated with Z _n I ₂ aqueous solution of the aforementioned mu. Also, 5 in FIG.
As a cation-exchange membrane for Asahi Glass Co., Ltd.
CMV (thickness about 0.13 mm) was used. This storage battery is a potentiostat / galvanostat HA-301 manufactured by Hokuto Denko KK
When the battery was charged with a constant current of 2 mA, the charging curve of (1) in FIG. 2 was obtained. Then, when the charging voltage reaches 1.5 V, charging is stopped, and then discharging is performed with a constant current of 2 mA, the discharge curve of (2) in Fig. 2 is obtained, and the discharge voltage decreases to about 1.0 V by about 210 Minutes of discharge could be performed. The discharge time taking into account the differences in -Z _n I ₂ concentration compared to the same battery was obtained by applying a mixture of nylon-6 and carbon powder in the carbon fiber-made plate (references supra) Also-because of the long length, the effect of using a porous material as the positive electrode material is clearly recognized. Such charging / discharging could be repeated.

Example 2. Alumina (for column chromatography, 30 sold by Wako Pure Chemical Industries, Ltd.)
(0 mesh) 62 mg and 7 mg of nylon-6 powder (manufactured by Spacey Chemical Co., Ltd.) and 12 mg of carbon powder (Ketjenblack sold by Lion-Akzo) are placed in an agate mortar and a small amount of formic acid is added to the mortar. Grind the whole. During grinding, most of the formic acid is lost by evaporation resulting in a powdery mixture. After removing formic acid by the natural evaporation method, this powdery mixture was molded at room temperature under a pressure of about 400 kg / cm ² to obtain a disc-shaped substance having a diameter of about 1.3 cm. This disc-shaped substance was used in Example 1. When immersed in an aqueous solution of Z _n I ₂ prepared in 1., about 0.1 g of the solution was absorbed. The thus-obtained porous material impregnated with Z _n I ₂ was used to manufacture the storage battery shown in FIG. In this embodiment, as shown in FIG. 1 and glass fiber paper, GA-100 manufactured by Toyo Paper Co., Ltd. (diameter slightly less than 1.3 cm) is used, and 110 μm each is used.
The above-mentioned Z _n I ₂ aqueous solution was soaked. The cation exchange membrane shown in FIG. 1 was the same as that used in Example 1. When the thus obtained storage battery was charged and discharged with a constant current of 2 mA in the same manner as in Example 1, a discharge time of 260 minutes could be obtained. Such charging / discharging could be repeated. The electrical conductivity of the discotic material obtained in this example was about 2 × 10 ^-3 Scm ^-1 at room temperature.

[Brief description of drawings]

FIG. 1 is a device diagram of a storage battery. 1 and 10 stop plate, 2 zinc plates, 3 and 6 glass fibers papermaking including the Z _n I ₂ aqueous solution, the plates 4 and 7 with a cutout hole, 5 cation exchange membrane, 8 zinc iodide A porous material impregnated with the solution, and 9 represents a platinum plate for current collection. 3 and 6 are fitted in the cut holes of 4 and 7, respectively, and the shape is changed depending on the shape of the porous substance 8 although it is shown as a rectangle in the figure. A storage battery is made by stacking these 1-10 with screws and nuts (see water supply in the detailed description of the invention). FIG. 2 is a charge / discharge diagram of the storage battery. (1) shows the charging curve and (2) shows the discharging curve.

Claims (7)

[Claims] 1. A dissociated metal iodide containing a porous material having an electric conductivity of 1 × 10 ⁻⁴ Scm ⁻¹ or more obtained by molding a mixture of a fine particle substance and carbon powder as an electrode material for a positive electrode. A secondary battery using a compound as an electrolyte. 2. The secondary battery according to claim 1, wherein a porous substance obtained by molding by pressurization is used as an electrode material for the positive electrode. 3. A porous material obtained by molding a mixture of a fine particle substance and carbon powder by sintering a fine particle substance as an electrode material for a positive electrode.
The secondary battery according to item. 4. The secondary battery according to any one of claims 1 to 3, which is obtained by using a polymer compound as the particulate substance. 5. The secondary battery according to any one of claims 1 to 3, which is obtained by using a polymer compound having an iodine-retaining power as the particulate substance. 6. The secondary battery according to claim 4, which is obtained by using polyamide as the polymer compound. 7. The secondary battery according to claim 1, which is obtained by using clay or alumina as the particulate material.