JPH01279565A - Nonaqueous solvent battery - Google Patents

Abstract

PURPOSE:To increase heavy-load discharge performance by using specifically treated chemical manganese dioxide as a positive active material and carbon black having specified specific surface area as a positive conductive material. CONSTITUTION:A positive mix 2 is accommodated in a positive container 1 made of stainless steel. Manganese trioxide (Mn2O3) prepared by baking manganese sulfate crystal is immersed in a sulfuric acid solution to convert into manganese dioxide (MnO2), and this manganese dioxide is washed, dried, and pressed to obtain chemical manganese dioxide, then this chemical manganese dioxide is heated for 8 hours at 400 deg.C in the atmosphere. This chemical manganese dioxide is mixed with carbon black whose specific surface area is 90-150m<2>/g and a binder, then this mixture is molded in a pellet to form the positive mix 2. A separator 3 and a negative electrode 4 are placed on the positive mix 2, and a nonaqueous solvent electrolyte is impregnated in the separator 3. The opening of the positive container 1 is crimped against a negative container through a gasket 5 to seal a battery. The heavy-load discharge performance of the battery is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a non-aqueous solvent battery, and particularly to a non-aqueous solvent battery in which the composition of the positive electrode is improved.

[Prior art] Nonaqueous solvent batteries that use light metals such as lithium and sodium as negative electrode active materials have high energy density, excellent storage characteristics, and a wide operating temperature range, and are used in calculators, watches, and memories. Although it is often used as a backup power source, heavy load discharge performance has recently been required. In addition, in such a non-aqueous solvent battery, the selection of a positive electrode active material to be combined with a light metal such as lithium or sodium, which is a negative electrode active material, is extremely important because it affects the battery performance.

By the way, many materials have been considered as positive electrode active materials for use in the above-mentioned batteries, and among them, manganese dioxide has been widely used because it has relatively excellent performance and is chemically stable. It is used. Among these manganese dioxides, electrolytic manganese dioxide obtained by electrolytically oxidizing manganese sulfate is generally used in nonaqueous solvent batteries. Further, the positive electrode of a non-aqueous solvent battery is made of a composition in which a conductive material and a binder are added to and mixed with the above-mentioned active material. Conventionally, acetylene black, graphite, and the like have been frequently used as the conductive material.

[Problems to be Solved by the Invention] However, non-aqueous solvent batteries incorporating a positive electrode using electrolytic manganese dioxide as an active material and acetylene black or graphite as a conductive material cannot sufficiently cope with the above-mentioned improvement in heavy load discharge performance. There was a problem that I couldn't do it. That is, acetylene black, which is blended together with electrolytic manganese dioxide to constitute the positive electrode, has excellent liquid absorption properties, but is poor in electrical conductivity.

On the other hand, although graphite has excellent conductivity, it has poor liquid absorption properties. Therefore, when a positive electrode is constructed using these conductive materials, the liquid retention or conductivity of the positive electrode is reduced, making it difficult to reduce the internal resistance of the battery and to improve the discharge performance. Further, even a positive electrode containing both of them cannot overcome the above-mentioned drawbacks. Furthermore, electrolytic manganese dioxide does not necessarily have sufficient properties as a positive electrode active material, and furthermore, its production requires a long time for electrolysis and consumes a lot of electricity, which increases production costs. There was a problem.

The present invention has been made to solve the above-mentioned conventional problems, and aims to provide a non-aqueous solvent battery with excellent lightning discharge performance.

[Means for Solving the Problems] The present invention provides a nonaqueous battery comprising a negative electrode using a light metal as an active material, a positive electrode comprising an active material, a conductive material, and a rejuvenating agent, and a nonaqueous electrolyte. , the positive electrode active material is manganese sesquioxide (Mn2O3) obtained by roasting manganese sulfate crystals.
) in sulfuric acid solution to produce manganese dioxide (MnO2).
It is characterized in that it is made of chemical manganese dioxide obtained by washing, drying, and pressing this, and that the conductive material is made of carbon black with a specific surface area (value determined by the BET method) of 90 to 150 m2/g. It is a non-aqueous solvent battery.

Examples of the light metal as the negative electrode active material include lithium, sodium, potassium, calcium, magnesium,
Examples include aluminum, with lithium and aluminum being particularly preferred.

Examples of the electrolyte include propylene carbonate,
1. Electrolyte such as lithium perchlorate, lithium borofluoride, lithium chloride, etc. dissolved in a non-aqueous organic solvent such as 2-dimethoxyethane, γ-butyrolactone, tetrahydrofuran, dioxolane, etc. at 0.2 to 1.5 mol/min. is used.

The detailed method for producing chemical manganese dioxide used as the positive electrode active material is as follows. First, manganese sulfate crystals are roasted in an air atmosphere or an oxygen atmosphere with a higher oxygen partial pressure than air at 800 to 1100°C for 10 minutes or more to decompose the manganese sulfate and oxidize the manganese to Mn2O3 as the main component. prepare something Subsequently, this manganese oxide is acid-treated with sulfuric acid. As a result, the disproportionation reaction shown in the following formula occurs and manganese dioxide is produced.

Mn2O3 ”H2804-MnO2+Mn5O4+H
2O month n304 +2112804 →, MnO2+2
MnSO4+2112O After washing the M2O3 produced in the above reaction with water, neutralizing it, and drying it, the resulting powder is compression molded into a flat plate shape under a pressure of 1 to 10 tons/d using a roll press, and then pulverized to a predetermined particle size. to produce chemical manganese dioxide.

Carbon black having the above specific specific surface area is produced by the following method. First, a liquid hydrocarbon having a carbon atom/hydrogen atom weight ratio of 9 or more is partially oxidized in a furnace in the presence of gaseous molecular oxygen and water vapor to generate a synthesis gas and to generate carbon as a by-product. The liquid hydrocarbons used here include, for example, naphtha pyrolysis oil (ethylene heavy end), aromatic hydrocarbons mixed with carbon (carbon oil), aromatic hydrocarbons mixed with C heavy oil, etc. Oil etc. can be mentioned. The water vapor is heated at a temperature of 0 to 800 K per 1 ton of liquid hydrocarbon in order to produce the desired carbon as a by-product.
'j, preferably use 4oo to 8oo. The temperature in the furnace is 12O0-1450'C, preferably 130
The temperature was 0 to 1450°C, and the pressure during the reaction was 10 to 80 atm.
Preferably the pressure is 25 to 80 atmospheres. Subsequently, the by-product carbon was heated to a temperature of 300 to 90% (0.5% at 1'C) under a nitrogen atmosphere.
Dry for 5 to 3 hours, and then dry for 1000 min under an inert gas atmosphere.
Carbon black having the specific surface area described above is produced by heat treatment at ~3000°C for 0.5 to 5 hours.

The reason why the specific surface area of the carbon black is limited is that if the specific surface area is less than 90 m2/9, the liquid retention property will decrease and the discharge performance will deteriorate.
If it exceeds /g, it means insufficient heating in the manufacturing process, and the functional groups remain and reduce chemical manganese dioxide, resulting in capacity deterioration. In addition, such carbon black is JIS
It is desirable that the amount of hydrochloric acid absorbed by K149B is 2OM15 g or more.

Examples of the binder include polytetrafluoroethylene, polyacrylic acid, and salts thereof.

The compounding ratio of chemical manganese dioxide as an active material, carbon black as a conductive material, and binder constituting the positive electrode may be in the range of gθ~94:5~15; I~5 in terms of weight ratio. desirable. Deviation from such a blending range may lead to a decrease in conductivity, discharge capacity deterioration, and moldability.

[Function] According to the present invention, the interface in contact with the electrolyte can be enlarged by using chemical manganese dioxide with a large specific surface area obtained by processing and press-molding a specific raw material as the active material that is the main component of the positive electrode. Therefore, compared to conventional electrolytic manganese dioxide, electrode reactions can proceed more smoothly under heavy loads. Further, carbon black with a specific specific surface area used as a conductive material has a higher degree of graphitization on the particle surface than acetylene black, and has excellent liquid absorption properties and conductivity. Furthermore, since such carbon black has few functional groups on the particle surface, deterioration of chemical manganese dioxide, which is an active material, can be prevented.

Therefore, by constructing a positive electrode containing these chemical manganese dioxide and carbon black together with a binder and incorporating it into a battery, heavy load discharge performance can be greatly improved.

[Embodiments of the Invention] Hereinafter, an example in which the present invention is applied to a coin-type non-aqueous solvent battery will be described in detail with reference to FIG.

1 in the figure is a positive electrode container made of stainless steel, and a positive electrode mixture 2 is housed in this container 1. This positive electrode mixture 2 contains 400% of chemical manganese dioxide obtained by the method described above.
Carbon black with a specific surface area of 135 m2/g measured by the BET method and polytetrafluoroethylene were mixed in a weight ratio of 87:10:3, heated in air for 8 hours at Diameter 16m, thickness 1.71 [Il
, and was molded into pellets with a weight of 0.899.

Further, on the positive electrode mixture 2, a separator 3 made of a polypropylene nonwoven fabric and a negative electrode 4 made of metallic lithium are placed. The separator 3 is impregnated with an electrolytic solution in which lithium perchlorate is dissolved in a mixed solvent of propylene carbonate and 1,2-dimethoxyethane (weight ratio: 1=1) at a concentration of 1 mol/no. A negative electrode container B is provided at the opening of the positive electrode container 1 via a backing 5, and by caulking the negative electrode container B, the positive electrode mixture 2, separator 3, and negative electrode are placed inside the positive electrode container 1, negative electrode container B. 4 is sealed. This coin-shaped non-aqueous solvent battery has an outer diameter of 2 Ou and a thickness of 2.4 rm.

Comparative Example Electrolytic manganese dioxide heated at 400°C for 8 hours, graphite and polytetrafluoroethylene in a weight ratio of 87:
A coin-shaped nonaqueous solvent battery was assembled in the same manner as in the example except that a positive electrode mixture mixed at a ratio of 10:3 and molded into a pellet shape was used.

Therefore, for 20 batteries in this example and comparative example, 3
The battery was stored for 0 days, and then the discharge duration (discharge end voltage 2.OV) was measured when a 300Ω load was applied. The results are shown in Table 1 below as average values.

Table 1 [Effects of the Invention] As detailed above, according to the present invention, a non-aqueous solvent battery with excellent heavy load discharge performance can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a coin-shaped non-aqueous solvent battery showing one embodiment of the present invention. l...Positive electrode container, 2...Positive electrode mixture, 3...Cenoclator, 4...Negative electrode, 5...Backing, 6...
Negative electrode container. Applicant's agent Patent attorney Takehiko Suzue Figure 1

Claims (1)

[Claims] In a non-aqueous battery comprising a negative electrode made of a light metal as an active material, a positive electrode made of an active material, a conductive material, and a binder, and a non-aqueous electrolyte, the positive electrode active material is made by roasting manganese sulfate crystals. The conductive material is made of chemical manganese dioxide obtained by immersing manganese sesquioxide (Mn2O_3) in a sulfuric acid solution to obtain manganese dioxide (MnO_2), which is then washed with water, dried, and pressed, and the conductive material has a specific surface area of 90 to 150 m^.
A non-aqueous solvent battery comprising 2/g of carbon black.