JPH0654668B2 - Iodine battery - Google Patents

Description

[Detailed Description of the Invention] Usually, a chemical battery is made by utilizing the contact potential difference based on the difference between the oxidizing power and the reducing power of two kinds of substances, and the negative electrode active material has a strong reducing power and a positive ion. A substance that easily changes is used, and a positive electrode active material that is less likely to change to a cation or a substance that easily changes to an anion is used. Therefore, it is considered that a substance such as iodine that easily becomes an anion is one suitable as the positive electrode active material. However, nevertheless, there are not many examples of making batteries using iodine as the positive electrode active material.
The reason for this is that iodine has an electrical resistance (specific resistance = 10 ⁶ Ωcm) that is too high for use as an electrode body, and is inferior in terms of workability and strength.

However, recently, it has been found that some polymer compounds have iodine-retaining ability, and that substances obtained by retaining iodine in the polymer compound have electric conductivity or semiconductivity. The present invention applies this fact to the production of a storage battery, and by using the present invention, the above-mentioned drawbacks when iodine is used as an electrode material can be compensated. That is, some polymer-iodine composites obtained by allowing iodine to be retained in the polymer compound described in the claims have a certain degree of electrical conductivity, and the polymer compound has properties such as processability and strength. Since excellent materials can be obtained, various types of electrodes can be made, and thus storage batteries using these can be made.

The battery is charged by using the polymer compound shown in the claims as an anode and using a metal as a cathode and using a solution of a corresponding metal iodide as an electrolyte solution and applying a DC voltage thereto. At this time, iodine is deposited at the anode to form a complex with the polymer compound, and metal is deposited at the cathode. After this, the DC voltage is cut off, and both poles are connected with a conductor to generate discharge and obtain power.

Next, examples of the present invention will be described.

Example 1. 30 mg of powdery poly (2,5-thienylene) insoluble in chloroform when heated (molecular weight 2000 or more) was taken and solidified at room temperature at a pressure of 600 kg / cm ² using a Shimadzu molding machine. A copper wire is connected to one end of the disk-shaped solid body having a diameter of 1.3 cm thus manufactured by using a conductive resin (Electrodag + 502 sold by Furuuchi Chemical Co., Ltd.).

Next, the disk-shaped solid is connected to the positive electrode of a dry battery (voltage 3V), and the zinc plate is connected to the negative electrode of the dry battery to assemble the circuit of FIG. In FIG. 1, it was confirmed that when a zinc iodide aqueous solution (0.05 ml /) was used as the metal iodide solution, a current of 1.5 mA was passed through the circuit. After applying a current for 5 minutes and removing the dry battery, and connecting the poly (2,5-thienylene) electrode and zinc with a lead wire, there is a potential difference of 1.3 V between them, and the initial value is 2.
It was confirmed that a current of 0 mA flows. This means that iodine is formed on poly (2,5-thienylene) due to electrolysis under a DC voltage, which results in poly (2,5-thienylene).
It shows that a battery was formed between the (thienylene) -iodine adduct and the zinc plate.

Example 2 In the same manner as in Example 1, the storage battery shown in FIG. 1 was assembled using some polymer compounds, and after charging, the electromotive force shown in the table below,
And the current value was obtained. In both cases, the surface area (both sides) of both electrodes was about 0.5 cm ² , and when a copolymer was used as the polymer compound that forms an adduct with the positive electrode active material iodine, The ratio of the numbers of the respective structural units is about 1: 1.

Example 3 Poly (2,5-thienylene), which is soluble in chloroform when heated, is applied to a cloth woven of graphite fibers (Tokai Kosho Co., Ltd.).
By using the cloth-like substance thus obtained and a zinc plate, FIG.
The storage battery shown in was produced. In FIG. 2, the cross-sectional areas of the cloth-like material and the zinc plate are both about 2.0 cm ² . A fibrous substance such as paper containing an aqueous zinc iodide solution (0.08 mol /) is sandwiched between the two, and the three members are brought into close contact with each other. As shown in FIG. 2, when charging was performed with a DC voltage of 3 V and discharging was performed in the same manner as in Example 1, an electromotive force of 1.2 V and an initial current value of 2.5 mA were obtained. Instead of the aqueous zinc iodide solution as the electrolyte to be contained in the fibrous substance 3 of FIG. 2, a propylene carbonate solution of zinc iodide (0.05 mol /
), An electromotive force of 0.4 V and an initial current value of 0.4 mA were obtained. Similarly, when a tetrahydrofuran solution of zinc iodide (0.05 mol /) was used as the electrolyte solution, an electromotive force of 0.3 V and an initial current value of 0.3 mA were obtained. Furthermore, it has been found that, in general, a solvent capable of dissolving a metal iodide and having a conductivity with the metal iodide solution can be a solvent for the electrolyte solution in the storage battery of the present invention, like water.

[Brief description of drawings]

Fig. 1 is a device diagram of a storage battery. 1 is a polymer compound, 2 is a metal plate, 3 is a solution of metal iodide, and 4 is a charging battery. FIG. 2 is a device diagram of a layered storage battery. 1 is a cloth-like substance coated with a polymer compound, 2 is a metal plate, 3 is a fibrous substance containing a solution of metal iodide, and 4 is a charging battery.

Claims (1)

[Claims] 1. A metal iodide is prepared by using a polymer compound having a monomer unit having an aromatic group, a heterocycle or a hydroxyl group as one of its main constituents and having an affinity with iodine as a positive electrode body. Storage battery characterized by using as electrolyte