JPS6220251A - Secondary battery - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention Industrial Sapporo Hikari 1 The present invention relates to a secondary battery that has excellent charge/discharge reversibility, has an extremely low self-discharge rate, and is capable of operating at high current density. It is something.

Conventional I■11-/A lil? Currently, commonly used secondary batteries include lead acid batteries, N1/C
There are d batteries etc. These secondary batteries have a battery mill with a medium cell voltage of about 2.0V at most, and are generally aqueous batteries. In recent years, research has been actively conducted on the development of secondary batteries that use lithium as a negative electrode, such as secondary batteries that can achieve high battery voltage.

When l-i is used for the negative electrode, it is necessary to use a non-aqueous electrolyte because of the high reactivity between water and l-i.

However, when carrying out a secondary battery reaction using l-i as a negative electrode active material, dendrites occur when Li+ is reduced during charging, resulting in problems such as a decrease in charge/discharge efficiency and a short circuit between the positive and negative electrodes. be. Therefore, it prevents dendrites,
Many technological developments have been reported to improve the charge/discharge efficiency and cycle life of negative electrodes. Leeds'', edited by J. B. Calbuff 1, published by Academic Press, London (1983), by H. Abral.
lall et al, in “l it
hllmaatteries”, J, P, Gab
ano, edfjOr, academicpres
s, London (1983)), a method of preventing Li dendrites by adding additives to the electrolyte system, or alloying the electrode itself with Al [JP-A-59-108281], etc. is proposed.

In addition to alkali metals and alkali metal alloys such as Li/Aρ, it is also known to use conductive polymers having a conjugated double bond in the main chain as negative electrode active materials [di■-
・■Ichi Curfman.

G. Double Kaufer, N. G. Heeger, R. Kaboo, N. G. McDiarmid,
Physics Levi'], -, 826 volumes.

Page 2327 (1982)
n, J, W, aw4cr.

A, J, treeger, R, nianer, A, G
, HacDiarmid, phys.

Rev. L2327 (1982) ) Well-known conductive polymers used in this method include polyacetylene, polythiophene, polyparaphenylene, polypyrrole, and the like.

On the other hand, it is known that conductive 1/l polymers are used as positive electrode active materials, similar to negative electrode active materials, and T
It is also known to use compounds that form intercalation compounds with alkali metals such as +82, other calgenite compounds, inorganic oxides, and the like.

As a conductive polymer used as a positive electrode active material, 0
Including polyalebrene, similar to those used for poles,
Polybuophene, Vorithi A phton derivative, Voriparaf R
There are nylene, polyparafine derivatives, polypyrrole derivatives, polypyrrole derivatives, etc., and polymers of aniline and aniline derivatives are well known. In addition, specific examples of calgenite compounds and inorganic oxides used in the positive electrode active material include TiS2, Nl)S
, Mo s , CoS , FeS2°V20
5. Cr2O5, MnO2, 5f02゜C002,5n
02 etc. are known.

Among these positive electrode active materials, both the oxidation state and the reduction state are relatively stable in the air, and when used in batteries, they have good discharge normality, can operate with high charging density, and have low self-discharge. An example of an active material having a high energy density is aniline or a polymer of an aniline derivative.

Electrochemical methods and chemical polymerization methods are known as methods for producing polymers of aniline or aniline derivatives.

An example of a known document on the electrochemical polymerization method is Journal of the Chemical Society of Japan, 11.1801 pages (1984), and an example of a known document on the chemical polymerization method is A.G. Green and A. E. Woodhead, Journal of the Chemical Society, p. 2388, 1910 [^, G. Green
and A, E, Woodhead, 1. 'Ch
em, Soc.

2388 (19'IO)] is known, but generally, polymers of aniline or aniline derivatives are produced by the following method.

In the case of electrochemical polymerization, the polymerization of aniline or aniline derivatives is carried out by anodic oxidation, with a
0m A/cra 2, electrolysis voltage is usually 1-300
Within the range of V, a constant current method, a constant voltage method, and any other method can be used. The polymerization is carried out in an aqueous solution or a non-aqueous solvent such as an alcohol, a nitrile, or a mixed solvent thereof, but it is preferably carried out in an aqueous solution. The non-aqueous solvent may or may not dissolve the resulting polymer (oxidized polymer).

Suitable? The pl+ of the lightning solution is particularly limited to 4, but the pH is preferably 3 or less, particularly preferably 2 or less. Specific examples of acids used for pH adjustment include HCJI
, 1-IBF, CF
3 Cool-1, To12 S 04 and Tol
Examples include NO3, but are not particularly limited to these.

In the case of chemical polymerization methods, for example, aniline or aniline derivatives can be treated in aqueous solution with oxidizing strong acids or with strong acids such as peroxides, such as 1N! Oxidative polymerization can be carried out by adding potassium acid. The polymer (oxidized polymer) obtained by this method can be made into a powder in a quantity of 1 q, and can be used after being separated and dried.

In addition, in both the electrochemical polymerization method and the chemical polymerization method, additives such as carbon black, Teflon powder, polyethylene glycol, polyethylene oxide, etc. may be added to the polymerization electrolyte for polymerization. It is also possible.

When using a polymer of aniline or an aniline derivative obtained by the above electrochemical polymerization method or chemical polymerization method as an electrode active material, the resulting polymer has already been doped during polymerization, so it must be dried. Either use it as is, wash the polymer with water to remove impurities and then dry it under reduced pressure, or wash the polymer with a solvent used in batteries and dry it under reduced pressure before using it. Since it is produced in an acidic solution, it is used after being treated with an alkali, or after using these methods (1) and 1).

The method of forming a polymer of 1-coupled aniline or an aniline derivative into an electrode is usually a metal current collector.
A method is used in which a polymer of aniline or an aniline derivative is placed on a substrate, and then pressed using a pressure molding machine to form the shape of an electrode.

At this time, if the bond between the metal current collector and the aniline or aniline derivative is weak, a binder such as polytetrafluoro-L-brene may be mixed with the aniline or aniline derivative polymer before addition. Pressure forming and reeling methods are used.

However, the electrode obtained by pressure molding by the above method has a high bulk density of 09 to 1.5 g/cm'' of aniline or aniline derivative polymer, so it is difficult to use it as a battery electrode. When used in batteries, the amount of electrolyte contained inside the electrode is limited (the amount of electrolyte absorbed is small), high doping is not possible, energy efficiency is poor, and it is difficult to obtain batteries with high current density. , :.

As a result of various studies conducted by the Ministry of Invention and others to solve the drawbacks of these conventional techniques, the Ministry of Invention and others have developed a method of using porous aniline or a polymer of aniline derivatives as a positive electrode. The present inventors have discovered that a high-performance secondary battery that can be charged and discharged at a high current density can be obtained by using the method, and have completed the present invention.

That is, the present invention uses aniline or a polymer of an aniline derivative for the positive electrode, and uses an alkali metal, an alkali metal alloy, a conductive polymer, or a composite of an alkali metal alloy or aluminum and a conductive polymer for the negative electrode. In a secondary battery, the positive electrode has a bulk density of 0.1 to 0.
The present invention relates to a secondary battery characterized in that it uses a porous aniline or aniline derivative polymer of 8 g/cm3.

In the present invention, the bulk density used as the positive electrode is 0.1
-0.8'J/crtr3 porous aniline or aniline derivative polymer can be prepared, for example, by blending a sublimated bamboo material into a polymer of aniline or aniline derivative and adding F[
After molding, it can be produced by heating to the sublimation temperature of the organic sublimable substance under normal pressure or reduced pressure to remove the organic sublimable substance.

The aniline or aniline derivative polymer used to produce the porous aniline or aniline derivative polymer may be aniline or 1,1
Refers to an oxidized polymer of aniline-derived ipho.

3 R4 [In the formula, R1-R4 may be different or the same, and are hydrogen atoms, alkyl groups having 1 to 10 carbon atoms, and 1 to 10 carbon atoms.
10 Al]gisyl Lt1 allyl group or carbon number 6-1
0 aryl group is shown. ] Typical examples of aniline or aniline derivatives generally referred to in item 1-1 include aniline, 2-meth-1-cy aniline, 3-meth-1-cy aniline,
2,3-dimethoxy-aniline, 2,5-dimethoxy-
Aniline, 2,6-dimethoxyaniline, 3゜5-dimethoxy-aniline, 2-Ij~xy~3-methoxy-aniline, 2.5-Schif∙niruaniline, 2-phenyl-3-methoxyaniline, 2゜3.5-t~rimethoxyaniline, 2,3-dimedyruaniline, 2,
Examples include 3,5,6-tetramethyl-aniline, among which aniline is the most preferred.

As mentioned above, the polymer of aniline or aniline derivative can be produced by either electrochemical polymerization method or chemical polymerization method.

The organic sublimable substances to be added to the II compound of aniline or aniline derivatives include dimethylbenzoquinone,
Examples include tolu4one, chromone, canine phthalene, naphthoquinone, benzylbenzoic acid, chloro1]benzoic acid, tric[10benzoic acid, trichlorohuman[1quinone, and benzoquinoline]. The sublimation temperature of these organic sublimable substances is 40
Preferably, the temperature is within the range of 250°C to 250°C. Also,
It is desirable that the compounding amount of the natural substance is 10 to 1500% by weight, preferably 100 to 1000% by weight, based on the polymer of aniline or aniline derivative.

The pressure when producing an electrode by pressure molding a mixture of a polymer of aniline or an aniline derivative and an organic sublimable substance is usually in the range of 10 Kg/cm2 to 5↑/cm2, but preferably 500 Kg/cm2 to 5↑/cm2. Kg/cm 2 to 21'
/cm2 range. It is desirable that the humidity at the time of pressurization is 4 degrees Celsius or less, preferably 30 degrees Celsius or less, for the organic material used.

The formed electrode is heated at the sublimation temperature of the right R gastric substance,
Under normal pressure or reduced pressure, cover the right I14 bamboo tube with a four-way diameter 14 porous electrode.

Incidentally, operations such as molding, sublimation, and heating are preferably performed in an atmosphere of an inert gas such as argon or nitrogen or under vacuum. In this way, the bulk density is 0.1'J/crn3
Porous aniline with a weight of 0.8g/cra3! , : can produce polymer electrodes of aniline derivatives.

The other side of these bulk densities is 0.15 in the present invention.
It is preferable to use a material having a bulk density m of 0.65 g/cm3 as the positive electrode.

If the bulk density of the porous aniline or aniline derivative polymer electrode is less than 0.1 g/cm3, the mechanical strength is undesirably low and the energy density per battery volume is low. On the other hand, if the bulk density is greater than 0.8 g/cm3, the holding capacity of the electrolyte is small, which not only makes charging at high current density difficult;
Doping occurs locally within the electrode, and operation at high doping levels is not possible, resulting in a high self-discharge rate and low energy density per battery weight.

Examples of the alkali metal used as the negative electrode active material in the present invention include I-i, Na, etc., and examples of the alkali metal alloy include li/Al.

Li/H9, Li/Zn, li/Cd,
Examples include I-i/Sn, Li/Pb, and alloys of three or more metals including alkali metals used in these alloys. Examples of the conductive polymer include polypyrrole and polypyrrole derivatives, polythiophene and polythiophene derivatives, polyquinoline, polyacene, polyparaphenylene, polyacetylene, and the like. Furthermore, examples of the composite include a composite of an alkali metal alloy such as ii/A1 alloy and various conductive polymers, or a composite of aluminum and various conductive polymers. The term "composite" as used herein refers to a modified product in which a uniform ffj inclusion, a laminate, and a base component of an alkali metal alloy or aluminum and a conductive polymer are modified with another component.

The solvent for the electrolytic solution used in the secondary battery of the present invention is preferably one that is nonprone and has a high dielectric constant. for example,
T, -fluors, ketones, amides, sulfur compounds, phosphate ester compounds, chlorinated hydrocarbons, esters, carbonates, nitro compounds, sulfolanes, etc. can be used, but among these, ■-Chils, ketones, phosphate ester compounds, chlorinated hydrocarbons,
Carbonates and sulfolanes are preferred. Typical examples of these include tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioquinone, monoglyme,
-Methyl-2-pentanone, 1,2-dichloroethane,
γ-butyrolactone, valerolactone, dimethoxyethane, methylformate, propylene carbonate, ethylene carbonate, dimethylformamide, dimethyl sulfoxide, dimethylthioformamide, ethyl phosphate, methyl phosphate, chlorobenzene, sulfolane, 3-
Examples include methylsulfolane. These solvents may be used in combination of two or more.

Further, specific examples of the supporting electrolyte used in the battery of the present invention include +-z]F6. Circle Sb F6゜Li C1JO,1
, -i As F6. CF35o31-i.

Li B[4, Li R(Fall >4°mouth B([t
) (Fall>, NaPF6゜NaB,
NaASF6. NaB (Bll) 4゜KB (Bll >
, KAS F6, etc., but are not necessarily limited to these. These supporting electrolytes may be used alone or in combination of two or more.

The concentration of the supporting electrolyte cannot be unconditionally defined because it varies depending on the type of aniline or aniline derivative polymer used in the positive electrode, the type of cathode, charging conditions, operating temperature, type of supporting electrolyte, type of organic solvent, etc. However, it is generally preferably within the range of 0.5 to 10 mol/liter. The electrolyte may be homogeneous or heterogeneous.

In the secondary battery of the present invention, the dopant skewer doped into the polymer of 7-niline or aniline derivative is 10 to 180 mol % with respect to 1 mole of repeating medium of the polymer of aniline or aniline derivative, Preferably 20
~100 mol%.

Dope suspension can be freely controlled by measuring the amount of electricity flowing during electrolysis. The doping may be carried out either under constant current, constant voltage or under varying conditions of current and voltage.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 [Manufacture of polyaniline] While stirring 100 cc of an aqueous solution of lN-1-111 with an aniline m degree of 0.22 mol/ρ using a magnetic stirrer, 0.25 mol/1 equivalent of ( N.H.
4) 2S208 was added to chemically polymerize aniline.

The 1q polyaniline obtained was in powder form. This was filtered and dried at 80° C. for 3 hours under reduced pressure.

Powdered polyaniline and 2゜3-dimethylbenzoquinone (sublimation temperature 58°C) were used as the organic tetrachromatic substance, and after thoroughly mixing them in a weight ratio of 10:90, a 10 mφ
(7) Mold 234Il+! ? Filled, 0.5t/cil
An electrode was produced by molding at a pressure of I2. Next, the electrode was placed in a glass tube and heated in an electric furnace for 4 hours while reducing the pressure.
After being held at 0°C for 30 minutes, it was cooled.

Dimethylbenzoquinone crystals were collected in the vacuum line trap. The resulting electrode has a thickness of 0.036
c11, the weight is 4Itg, and the bulk density is 0.17g
/cm3.

[Battery performance test]

The porous polyaniline electrode formed by the above method was used as the positive electrode, and the negative electrode was used as the negative electrode.
oto, I and YallallOtO, ^, Ch
eII1.1. ett.

Voriparaff I nylene powder 35IFI, acetylene black 3, synthesized from dibenzene using Grignard reagent according to the method described in [1977, 353].
10. Mix 51Fl and 3.5Rg of Teflon powder, place this mixture on a Niracle wire mesh, and dry. Use a pressure-molded disk with a diameter of φ, and connect +-ts between the positive and negative electrodes.
ml of F4 is 1 mol/I of propylene carbonate and 1
, 2-dimexyethane, and 2-dimexyethane in a volume ratio of 1:1.The battery characteristics were investigated using the experimental cell shown in the figure, which was sandwiched between polypropylene diaphragms impregnated with a mixed solvent electrolyte having a volume ratio of 1:1.

The current density for charging and discharging is set to 5 mA/cta 2, and first the battery voltage is 2.0 mA/cta 2 from the discharge direction. It was discharged until it reached Ov. Next, the battery was charged at the same current density until the battery voltage reached 4.3 μ. Hereinafter, repeated charging and discharging tests were conducted under the same conditions.

At the 8th cycle, a nearly constant amount of charge and discharge electricity is reached, with a value of 11.63 coulombs, which corresponds to a doping level of 65 mol% for the net positive electrode polyaniline, and for the negative electrode polyparaphenylene. This corresponds to a doping level of 26 mol%.

Even at the 200th cycle, this battery can charge and discharge approximately the same amount of N air as the 8th charge/discharge charge, and when a 120-hour self-discharge test was conducted at the 201st cycle, the self-discharge rate was approximately 1. It was 3.2% in February.

Example 2 Nophthalene (sublimation temperature 80.5
The procedure was carried out in the same manner as in Example 1, except that the temperature (°C) was used. The obtained electrode has a thickness of Q, 036 cm and a weight of 18 Rg.
The tear and bulk density was 0.649/cm3.

Hereinafter, a battery performance test was conducted in the same manner as in Example 1, and the charge/discharge efficiency at the 210th cycle was 100%. Further, when the self-discharge test was conducted for the 211th time, a self-discharge rate of 2.8% was measured in 600 hours.

Comparative Example An electrode was produced in the same manner as in Example 1, except that 34 mg of the same powdered polyaniline as in Example 1 was used and molded without adding any organic sublimable substance. The 1q electrode had a thickness of 0.043ctnz, a weight of 34η, and a bulk density of 1.009/crt+3.

Battery 1! In the performance test, under the same conditions as in Example 1, the charging voltage suddenly increased to 4 from the middle of charging, and the predetermined voltage reached 4.
Electricity that can be charged until it reaches 3V (because there is little,
The experiment was carried out by reducing the value from 5 In A/cm2 to 3711Δ/cm2. The charging/discharging efficiency Gj at the 200th cycle is 98%, and the self-discharging rate at the next cycle is:
It was 15% between 600$ Il'i.

Effects of the Invention As described above, the secondary battery of the present invention uses a porous aniline or aniline derivative polymer with a low bulk density as the positive electrode. Compared to conventional secondary batteries used in

[Brief explanation of the drawing]

The figure is a schematic cross-sectional view of a battery cell for measuring characteristics of a secondary battery, which is a specific example of the present invention. 1... Nickel lead wire for negative electrode 2... Nickel mesh current collector for negative electrode 3... Negative electrode 4... Porous polypropylene spacing 5... Positive electrode 6... Nickel mesh for positive electrode TEPCO Body 7... Positive electrode lead wire 8... Teflon container Patent applicant Showa Denko Co., Ltd. 1 Hitachi Ltd. Representative Patent attorney Sei Kikuchi 20 - Figure

Claims (1)

[Claims] Using aniline or aniline derivative polymer for the positive electrode,
In a secondary battery using an alkali metal, an alkali metal alloy, a conductive polymer, or an alkali metal alloy or a composite of aluminum and a conductive polymer as a negative electrode,
The positive electrode has a bulk density of 0.1 to 0.8 g/cm^3
A secondary battery characterized by using a porous aniline or aniline derivative polymer.