JPH10294107A - Negative electrode active material for alkaline storage battery and battery using this - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a storage battery of an electrode of a small and thin type by using a compound having a quinone structure to form a complex with a metallic ion for an alkaline storage battery as an active material. SOLUTION: In a negative electrode plate 1, 2,5-dichloro-3,6 dihydroxy-p- benzoquinone is agitated by an alkaline aqueous solution, for example, KOH, and after it is left as it is for a day, an obtained precipitate is filtered and dried, and a complex with a metallic cation is formed as an active material. This is mixed with carbon of a conductive material, a 1 wt.% aqueous solution of carboxymethyl cellulose is added and paste is made, a fluororesin is added as a binding agent, and is applied to both surfaces of a copper current collecting body, and is pressed to a prescribed thickness after drying, and a negative electrode is obtained. In a positive electrode plate 2, a conductive material and a nickel hydroxide are mixed, the 1 wt.% aqueous solution of carboxymethyl cellulose is added and paste is made, a fluororesin is added as a binding agent, and is applied to both surfaces of a nickel current collecting body, and is pressed to a prescribed thickness after drying, and a positive electrode is formed. Nonwoven fabric is used as a separator, and KOH is used as an electrolyte.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a negative electrode active material for an alkaline storage battery and a battery using the same.

[0002]

2. Description of the Related Art In recent years, portable devices have been increasingly miniaturized, and it is inevitably demanded that storage batteries, which are power sources of such devices, be miniaturized and have high energy density.

A nickel-cadmium storage battery using nickel hydroxide as a positive electrode active material and cadmium as a negative electrode active material has been widely used for a storage battery using an alkaline electrolyte. However, the influence of cadmium on environmental problems has been increasing. There has been concern that nickel-metal hydride storage batteries using a hydrogen storage alloy as a substitute have been put to practical use. This at the same time enabled the high capacity and high density required of the storage battery.

[0004] Alkaline storage batteries have a feature that they can be charged and discharged with a large current and have a long cycle life. In recent years, as various electronic devices have become portable and cordless, nickel-cadmium and nickel-hydrogen storage batteries have been developed. While the weight energy density is about 70 Wh / Kg, development of lithium ion storage batteries having a weight energy density higher than that is progressing. However, alkaline storage batteries, which are superior in safety, are expected to be further reduced in size and weight, and development is urgent.

[0005] Among storage batteries using an alkaline electrolyte, a storage battery using cadmium or a hydrogen storage alloy as a negative electrode active material has a large weight per unit volume of the active material itself and constitutes a small and thin storage battery. It is difficult. Therefore, a material having a small weight per unit volume of the active material itself and good moldability has been demanded.

[0006]

One of the above-mentioned materials is an organic compound having a quinone structure. As a material using such a compound having a quinone structure as an active material, a redox polymer having a quinone structure in a side chain in an aqueous acid solution or a non-aqueous solution is used as an electrode material (Japanese Patent Laid-Open No. 6-56989). ) Has been proposed.

However, many compounds having a quinone structure dissolve in an aqueous alkaline solution, and although attempts have been made to use them as polymer batteries by making them thinner as proposed in the above publication, Application to active materials for alkaline storage batteries has been very difficult.

An object of the present invention is to solve the above problems and to provide an alkaline storage battery which is small and thin and has a low weight energy density.

[0009]

According to the present invention, in order to achieve the above object, a compound having a quinone structure and forming a complex with a metal cation is used as a negative electrode active material.

[0010]

DETAILED DESCRIPTION OF THE INVENTION 2,5-Dichloro as a quinone compound
The structure of -3,6-dihydroxy-p-benzoquinone is shown on the left side of FIG. Although p-benzoquinone is known to be a reversible reaction system, it cannot be used as an electrode material of an alkaline storage battery because it is soluble in an aqueous alkaline solution.

However, by having a hydroxyl group such as a compound having a halogen group at the 2,5-position and a hydroxyl group at the 3,6-position of the benzoquinone structure, as shown in FIG. When touched, a stable complex can be formed with the metal cation, and the following electrochemical reaction becomes possible. That is, when the potential is swept in the electrochemical reduction direction, protons enter the complex, and the carbon-oxygen double bond at the para-position is broken to form an OH bond. Conversely, when the potential is swept in the electrochemical oxidation direction after the reduction reaction, the para-OH
The bond undergoes a dehydrogenation reaction, again forming a carbon-oxygen double bond.

[0012] Such an effect is obtained because, even when the functional group is only a halogen group such as tetrachloro-p-benzoquinone, chloride existing at one opposing position is easily subjected to nucleophilic substitution. Form a complex. Further, the cyano group or the halogen group has an effect of helping to stabilize an ionic bond with a metal cation necessary for complex formation due to their strong electronegativity.

[0013]

Next, specific examples of the present invention will be described. FIG. 2 shows a nickel quinone storage battery according to one embodiment of the present invention. 1
Are negative plates using the quinone complex according to the present invention as a main component, 2
Is a positive electrode plate mainly composed of nickel hydroxide, 3 is a separator, 4 is a case, 5 is an insulating plate, 6 is a safety valve, 7 is a sealing plate, 8 is a positive electrode terminal, and 9 is a positive electrode lead.

An example of the present invention will be described with respect to a method for manufacturing the negative electrode plate 1. First, 2,5-dichloro-3,6-dihydroxy-p-benzoquinone was stirred in an aqueous alkali solution (KOH) and allowed to stand for one day, and the resulting precipitate was filtered, dried, and dried with a metal cation. The complex was obtained. This complex was mixed with carbon as a conductive material, a 1% by weight aqueous solution of carboxymethylcellulose was added to form a paste, and a fluorine-based resin was further added as a binder and applied to both surfaces of the copper current collector. After drying this, it was pressed to a predetermined thickness to obtain a negative electrode.

On the positive electrode plate 2, a conductive material and nickel hydroxide are mixed, a 1% by weight aqueous solution of carboxymethylcellulose is added to form a paste, and a fluororesin is added as a binder, and the paste is applied to both surfaces of the nickel current collector. I wore it. After drying this, it was pressed to a predetermined thickness to obtain a positive electrode. An electrode group is formed by using a nonwoven fabric made of hydrophilic polypropylene as a separator, inserted into a metal case, injected with an aqueous solution of caustic potassium having a specific gravity of 1.3 as an electrolytic solution, and then sealed to close a nickel-quinone storage battery. Was configured.

FIG. 3 shows a charge / discharge curve of this battery. The battery size was AAA, the nominal capacity was 300 mAh, and the charging and discharging currents were both 0.1 C. Charge voltage is about 1.3
V and the discharge voltage were about 1.15V.

In this embodiment, the metal cation forming the complex can be changed by changing the solute of the alkaline aqueous solution which is left for one day. However, even when the metal cation is different (lithium, sodium, barium), potassium is changed. The same characteristics as in the case of were obtained.

From such a mechanism, it is considered that similar characteristics can be obtained in a polymer compound having a complex having a quinone structure in the main chain.

Further, it is considered that by optimizing the manufacturing conditions of the electrode substrate and the negative electrode, a larger current can be passed.

[0020]

As described above, according to the present invention, a compound having a quinone structure which forms a complex with a metal cation can be used as an active material. Further, by using this active material for an alkaline storage battery, a small and thin electrode and a storage battery can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the structure of a compound having a quinone structure and a metal complex thereof used in one example of the present invention.

FIG. 2 is a schematic configuration diagram of a nickel-quinone storage battery in one embodiment of the present invention.

FIG. 3 is a diagram showing charge / discharge characteristics of the present embodiment.

[Explanation of symbols]

 1 Negative electrode using quinone compound 2 Nickel hydroxide positive electrode 3 Separator

Claims (3)

[Claims] (1) a metal cation (Li +,
A negative electrode active material for an alkaline storage battery, which is a compound that forms a complex with (Na +, K +, Ba2 +). 2. The compound has a hydroxyl group (—OH) as a functional group.
2. A compound having at least one of a group, a cyano (-CN) group or a halogen (-F, -Cl, -Br) group.
The negative electrode active material for an alkaline storage battery according to the above. 3. A negative electrode using the active material according to claim 1,
An alkaline storage battery comprising a positive electrode using a metal oxide and an alkaline electrolyte.