JPS5835871A - Air cell - Google Patents

Abstract

PURPOSE:To obtain an air cell which has a high voltage and a large capacity by using an electrolyte consisting of an aqueous ammonium chloride solution. CONSTITUTION:A positive lid 1 also serving as a positive terminal is in electrical contact with a porous carbonic bar 10, and has an air supplying hole 2. An air electrode 3, which is in contact with a lyophilic barrier 4, consists of cobalt phthalocyanine, active carbon and a water-repellent fluorine resin. A pasty electrolyte 5 prepared by kneading starch into 20wt% ammonium chloride solution used as an electrolyte is in contact with a negative electrode 6 made of a zinc can. In addition, a negative can 7 is sealed, with a gasket 8 interposed between the positive lid 1 and the negative can 7, by curving the opening of the lid 1 so as to seal the battery. A sealing member 9, which is made of a polyvinylchloride sheet and seals the air supply hole 2, is a pressure-sensitive tacky agent. Since metal phthalocyanine is combined with active carbon in this invention, the electrolyte 5 has a high reducing acitivity. Consequently, both the operational discharge voltage and the discharge capacity of the battery are increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air battery having an air electrode using oxygen in the air as an active material, using a metal chelate compound as the main catalyst of the air electrode and using an electrolyte containing ammonium chloride salt. This allows us to provide high-voltage, high-capacity air batteries.

Ammonium chloride aqueous solution has good electrical conductivity and excellent ability to form complex salts with zinc negative electrodes, so it has excellent properties as a battery electrolyte and was used as an electrolyte in air batteries.

However, in conventional air batteries based on ammonium chloride, the air electrode was made by impregnating activated carbon with a large surface area and a water repellent such as paraffin, but ammonium chloride has the ability to form complex ions with many metals. In the case of an air electrode in which fine iron powder, which has the ability to act as an oxygen reduction catalyst, is attached to activated carbon, the fine iron powder dissolves in the electrolyte and loses its catalytic ability during storage, reducing the oxygen reduction ability of the activated carbon itself. Therefore, after storage, the activity decreases, resulting in deterioration in performance and a decrease in discharge operating voltage.

The object of the present invention is to obtain a high-voltage, large-capacity air battery by using an electrolytic solution consisting of an aqueous ammonium chloride salt solution.

Embodiments of the present invention will be described based on the drawings.

A positive electrode lid 1 also serves as a positive electrode terminal, is in electrical contact with the porous carbon rod 10, and has an air supply hole 2. An air electrode 3 is made of cobalt phthalocyanide activated carbon and a water-repellent fluororesin, and is in contact with a lyophilic barrier 4. Reference numeral 5 denotes an electrolyte made of an electrolytic solution containing 20% by weight of ammonium chloride made into a paste with starch, which is in contact with the negative electrode 6 of the zinc can. 7 is a negative electrode can, and the opening of the positive electrode lid 1 is bent through a gasket 8 to seal the battery. Reference numeral 9 denotes a polyvinyl chloride sheet sealant that seals the air supply hole 2, and seals the air supply hole 2 of the positive electrode lid 1 with a pressure-sensitive adhesive.

The air electrode 3 has a surface area of approximately 800 m by the gas adsorption method.
/gO granular carbon black, 2g of cobalt phthalocyanine, which is a metal chelate compound eyelid, was mixed with 3g of quinoline.
00 C, C, and fully immerse 10 g of activated carbon in this solution. The quinoline was evaporated by pressure-sensitive drying at 111140°C in a liquid state, and then the cobalt phthalocyanine and carbon black coexistence was heat-treated at 500°C for 3 hours in an electric furnace in a nitrogen atmosphere. Furthermore, the air electrode 3 is formed into a cylindrical shape with the carbon rod 10 serving as a current collector as the center along with Teflon fine powder.

As for the coexistence of catalyst and activity, finely powdered metal phthalocyanine and activated carbon may be mixed, but the metal phthalocyanine is made water-soluble by sulfonating the 7 thalocyanine rings, and activated RK is adsorbed in an aqueous solution. There are also ways to remove water. As a result of examining heat treatment methods for these coexisting materials, we found that those treated in a nitrogen atmosphere at a temperature between 150"0 and 1300"O exhibited excellent oxygen reduction ability;
It is thought that the metal chelate compound of the catalyst changes into a highly co-rotatable bond due to the heat treatment, and the activity remains stable.

However, at temperatures below 150°C, the co-rotation does not proceed, so that little effect is observed, and at temperatures above 130G'0, the metal chelate compound heats up and sublimates more markedly.

The expected effect was not obtained. Note that the atmosphere for the heat treatment is an inert gas such as nitrogen or argon.

When carried out in hydrogen-based reducing gas or vacuum.

There was less weight loss due to oxidation, and the improvement effect was improved.

Since the air battery of the present invention uses ammonium chloride salt aqueous solution as the electrolyte 5 and metal 7 talocyanine with its activity, the oxygen reduction reaction has good activity and has no solubility in the electrolyte containing ammonium chloride. Therefore, a high voltage, large capacity air battery can be obtained without causing a decrease in battery discharge operating voltage or a decrease in discharge capacity.

Furthermore, when zinc chloride is added to the electrolytic solution of the battery of the present invention, corrosion of the zinc negative electrode 6 during storage can be suppressed, and an air battery with even better storability without self-discharge can be obtained. In addition to cobalt phthalocyanine, we conducted experiments with phthalocyanine of transition metals such as copper and nickel, and were able to obtain results superior to conventional products containing only activated carbon. Also,
As a result of testing catalysts having a porphyrin ring in addition to the phthalocyanine ring and metal gyrate compounds other than these, similarly excellent results were obtained9.

Next, JI using cobalt phthalocyanine, which is an example of the present invention, and using an electrolyte of ammonium chloride salt aqueous solution.
10 each of the present invention product (A), which is an air battery of the same type as 8LR6, and the conventional product CB), which is the same type of air battery that uses an ammonium chloride salt electrolyte only with activated carbon and is otherwise completely the same, was
The battery was discharged at a constant current of 150 mA at 5° C., and the discharge curve is shown in FIG. 2 and the discharge capacity is summarized in Table 1. In addition, the product of the present invention [λ)2
0 pieces and conventional product CB) 20 pieces were stored at 25°C, and in the 6th and 12th month, 10 pieces each were discharged with a constant current at 25°C and 150 nn&, and the results are summarized in Table 1.

From FIG. 2 and the table, it can be seen that the product of the present invention CA) has a high discharge operating voltage, a long duration, and excellent storage performance.

Furthermore, since the air battery of the present invention has an operating voltage of 1.5V, it is compatible with ordinary manganese dry batteries, alkaline manganese batteries, silver oxide batteries, nickel-zinc batteries, etc.

As described above, the air cell of the present invention having an air supply hole can discharge an air electrode made of a metal chelate compound, carbonaceous material, and a water-repellent fluororesin, an electrolytic solution made of an ammonium chloride salt aqueous solution, and a zinc negative electrode body. The operating voltage is high and the discharge capacity is also improved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an air cell according to an embodiment of the present invention, and FIG. 2 is a comparison diagram of discharge curves of a product (A) of the present invention and a conventional product (CB) at a fixed current of 25°C1150. 1...Positive electrode cover 2...Air supply hole 3
... Air electrode 5 ... Electrolyte 6 ...
...Negative electrode 12...Name of carbon rod patent applicant 11! '1 Figure 2 301

Claims (3)

[Claims] (1) An air battery comprising an air electrode containing a metal chelate compound, carbonaceous material, and a water-repellent fluororesin, an electrolytic solution containing an ammonium chloride salt, and a zinc negative electrode. (2) The metal chelate compound is co, Fe, Ni,
Mg, Cu. The air battery according to claim 1, characterized in that it has a phthalocyanine ring or a porphyrin ring centered on a transition metal such as Cr or Mn and surrounded by four nitrogen elements. (3) Claim 1 or 2, characterized in that the air electrode is heated from powdered or granular carbon to potash at a temperature in the range of 150°C to 1300°C, and uses zinc as a counter electrode. air battery.