JPS60221964A - Secondary battery - Google Patents

Abstract

PURPOSE:To increase discharge capacity of a secondary battery by using polyaniline which was electrolytically synthesized in hydrochloric acid solution as a positive active material. CONSTITUTION:A positive electrode containing polyaniline electrolytically synthesized in hydrochloric acid solution as a positive active material is used. Polyaniline alone or a mixture of polyaniline and conductive material such as carbon, graphite, or nickel is used. A negative active material is preferable to use a substance which can reversibly exchange cations with electrolyte repeatedly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a secondary battery characterized in that the positive electrode contains polyaniline electrolytically synthesized in a hydrochloric acid solution as an active material.

In recent years, batteries! ! ! Various studies have been conducted on secondary batteries that use conductive polymer materials as electrode active materials for the purpose of I, but among these batteries that use conductive polymer materials as electrode active materials, polyaniline is used as the electrode active material. The secondary battery used as a material is known as a conductive polymer material battery with excellent charge/discharge characteristics (for example, 24th Battery Symposium Abstracts, P, 197.1983).

However, conventional secondary batteries using polyaniline as an electrode active material have a discharge capacity of 100 to 110 A +1/k.
Q, and the discharge capacity is not sufficient for a battery that can be used practically.Therefore, it is desired to further increase the discharge capacity of a secondary battery using polyaniline as an electrode active material. ing.

In view of the above circumstances, the present inventors conducted intensive research on increasing the discharge capacity of secondary batteries using polyaniline as an electrode active material, and as a result, they discovered that a polyaniline cathode active material electrolytically synthesized in a hydrochloric acid solution. It has been found that by using the above object, the above object can be achieved.

That is, conventional polyaniline electrode batteries used polyaniline obtained by electrolytic synthesis in an aqueous perchloric acid solution as an electrode active material, but according to the studies of the present inventors, polyaniline It was discovered that when electrolytically synthesized in a hydrochloric acid solution and used as an electrode active material, the discharge capacity of a battery unexpectedly increases by approximately 50% compared to conventional batteries. This is what led to this.

The present invention will be explained in more detail below.

As described above, the secondary battery according to the present invention is a secondary battery formed from a positive electrode, a negative electrode, and an electrolyte, in which the positive electrode contains as an active material polyaniline electrolytically synthesized in a hydrochloric acid solution. According to the present invention, by using polyaniline electrolytically synthesized in a hydrochloric acid solution, the discharge capacity is surprisingly improved compared to conventionally known polyaniline electrode batteries. It is not clear why polyaniline electrolytically synthesized in a hydrochloric acid solution becomes an electrode active material that dramatically improves discharge capacity, but in any case, hydrochloric acid such as perchloric acid, sulfuric acid, nitric acid, etc. Even if polyaniline is electrolytically synthesized using an acid other than the above, the discharge capacity of the polyaniline electrode active material is low, and the object of the present invention cannot be achieved.

Here, the polyaniline used as the positive electrode active material of the secondary battery of the present invention is electrolytically synthesized by anodizing aniline in a hydrochloric acid solution as described above, but when polyaniline is electrolytically synthesized, Aniline is used in a hydrochloric acid solution at a concentration of 0.01 to 5 mol/J, preferably 0.5 to 3 mol/J. Also, the hydrochloric acid temperature is usually 0.0
The amount is 2 to 10 mol/J, particularly preferably 1 to 6 mol/J. Note that water is usually used as the solvent.

Furthermore, the electrolytic voltage when electrolytically synthesizing polyaniline is selected depending on the materials of the working electrode and the counter electrode, etc. For example, when platinum is used for the working electrode and the counter electrode, respectively, the electrolytic voltage is 0.8
-1.6V, especially 0.9-1.3V is suitable.

Note that the working electrode and the counter electrode can be made of any conductive material that is stable against hydrochloric acid, such as platinum, gold, palladium, silver, mercury, lead, carbon, graphite, tin oxide, indium oxide, etc. However, platinum, carbon, and graphite are particularly preferably used.

The positive electrode of the secondary battery of the present invention contains polyaniline electrolytically synthesized in a hydrochloric acid solution as the positive electrode active material, as described in -J Duplex, but in this case, it is also possible to use this polyaniline alone as the positive electrode, Furthermore, it is also possible to use this polyaniline in combination with a conductive substance such as carbon, graphite, or nickel, depending on the requirements.

In addition, various types of C can be used as the negative electrode active material contained in the negative electrode of the secondary battery of the present invention, but in particular, a material that can reversibly move cations into and out of the electrolyte is used as the active material. Preferably covered. That is, it is preferable that the negative electrode active material incorporates cations into the active material in a charged state (reduced state B) and releases cations in a discharged state (oxidized state). In this case, the negative electrode active material is preferably a substance having a high degree of conjugated bond in the molecule, specifically polyacetylene or polyparaphenylene.

Polymers of benzene and its derivatives, polypyridine, polythiophene, polyfuran, polypyrrole.

Examples include polynuclear aromatic compounds such as anthracene and naphthalene, their polymers, and graphite. Also, metals that can be monovalent or divalent cations, specifically lithium, s] to lithium.

Potassium, magnesium, calcium, barium.

Zinc and the like and alloys containing them (lithium-aluminum alloy, etc.) are also preferably used. Among these substances, Graphite 1~ is stable against oxygen, moisture, and heat, and exhibits good S'Fli properties in both neutral, oxidized, and reduced states. Most preferably used. In this case, if graphite is used, the charging/discharging rate and discharge capacity of graphite are very similar to those of polyaniline used in the present invention, so it is difficult to use a metal ion such as lithium. Even when using an electrolyte containing the above, it is possible to obtain a secondary battery in which no gentrite is generated at the negative electrode, which is very preferable.

Here, the graphite substance is a substance mainly composed of carbon and containing graphite or a structure similar to graphite. Specifically, carbon #i miscellaneous, carbon cloth, carbon foil, graphite 1lffi, graphite cloth, graphite foil, acetylene black, which are calcined natural or synthetic materials such as cellulose, pitch, polyacrylonitrile, and polyvinyl chloride. and natural graph eye 1~
etc. can be used.

Next, the electrolyte constituting the secondary battery of the present invention is a compound consisting of a combination of an anion and a cation, and an example of the anion is Pl:s-, 5llr6.

Halide anions of Group VA elements such as As Fe-, Sb C16-(7), halide anions of Group IIIA elements such as BFa-, /VC4-.

I-(I3-)+Br-*Halogen anion such as CR-, perchlorate anion such as ClOn-.

HF2-, CFsSO3-, CN5-. 5O4-.

Examples include HSo 4-, but the anion is not necessarily limited to these anions. In addition, cations include alkali metal ions such as li+, Na'', and ni+, and R4N'' (R represents hydrogen or hydrocarbon residue).
Examples include quaternary ammonium ions such as, but the cations are not necessarily limited to these cations.

Specific examples of electrolytes having such anion and cation A include L + pt2 e, Li Sb F 6 , l
i As Fs.

Li CRO4, Li I, Li Or, Li
(J.

mPFs, NaSbFe, NaAsPa
.

tbcjOa, Na1. KPFa, KSb F8
゜KAs Fa, KfJOa, Li BF4.

Li /V (Ja, Li HF2, Li CNS.

KSCN, Li SOs CFg.

(n-C4Hy)4NAsFe.

(nC4H7)4NPFa.

(n -C4Hy)a NClO4゜(n -04H
7)4 NBF4.

(C2H5)aN(JO<.

(n-CaH7)4N Y etc., but the present invention is not limited to these compounds.

Note that these electrolytes are usually used in a state dissolved in a solvent, and in this case, the solvent is not particularly limited, but a relatively highly polar solvent is preferably used. Specifically, propylene carbonate.

Ethylene carbonate, benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, γ-butyrolactone, triethyl phosphate, triethyl phosphite.

One or a mixture of two or more of dimethyl 1iIII acid, dimethylbormamide, dimethylacetamide, dimethylsulfoxide, dioxane, dimethoxyethane, polyethylene glycol, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, water, and the like can be mentioned. Among these, nonaqueous solvents are preferred, and when a nonaqueous solvent is used as the solvent, the electromotive force of the battery increases.

The secondary battery of the present invention is usually constructed by interposing an electrolyte between the positive and negative electrodes, but in this case, if necessary, a porous membrane made of synthetic resin such as polyethylene or polypropylene or natural fiber paper may be used between the positive and negative electrodes. etc. can be used as a diaphragm.

In the secondary battery of the present invention, the positive electrode contains polyaniline electrolytically synthesized in a hydrochloric acid solution as an active material,
Since this has a very high discharge capacity and is lightweight, it is suitable for use in a wide variety of applications such as automobiles, airplanes, portable machines, and electric vehicles.

EXAMPLES Hereinafter, the present invention will be specifically explained by showing examples and comparative examples, but the present invention is not limited to the following examples.

[Example 1] An aqueous hydrochloric acid solution containing aniline at a concentration of 1 mol/J (hydrochloric acid 2 mol/J) was used as an electrolytic solution, and a platinum plate (2 x 2 ci) was immersed as a working electrode and a counter electrode in the electrolytic solution, and a constant potential was maintained. Polyaniline was synthesized by electrolysis (0.95V). At this time, the current density was about 4.2aIA/cd. The obtained polyaniline was thoroughly washed with distilled water and then thoroughly dried.

Next, this polyaniline was used as a positive electrode, and a 1 mm thick lithium plate (2 x 4 CT11) was used as a negative electrode.
The electrolyte was Li (J
A battery was constructed using a propylene carbonate solution of O4, and battery experiments were conducted. That is, as a charge/discharge test, 2I+1/
The operation of charging with a current of 1 and then discharging with a current of 2 such that the potential difference between the positive electrode and the negative electrode became 2.8 V was repeated. As a result, the charge/discharge efficiency in the fifth cycle was 98%, and the discharge capacity was 180% per 1 kg of polyaniline.
It was ΔII.

[Comparative Example 1] Polyaniline was synthesized in the same manner as in Example 1, except that an aqueous perchloric acid solution with a concentration of 2 mol/J containing aniline at a concentration of 1 mol/J was used as the electrolytic solution.

As a result of conducting a battery experiment using this polyaniline under the same conditions as C Example 1, the charge/discharge efficiency at the 5th cycle was 96.
%, and the discharge capacity was 108 Ah per 1 kg of polyaniline.

[Comparative Example 2] Ii containing aniline at a concentration of 0.4 mol/J 1 degree 1 mol/J
Polyaniline was synthesized in the same manner as in Example 1 except that the sulfuric acid aqueous solution of J was used as the electrolytic solution.

As a result of conducting a battery experiment using this polyaniline under the same conditions as in Example 1, the charge/discharge efficiency of the 5th cycle was 97.
%, discharge capacity is 110A11 per 1 kg of polyaniline
Met.

[Example 2] A hydrochloric acid aqueous solution containing 1 mol/J of aniline and 2 mol/J of WA was used as the electrolytic solution, and constant potential electrolysis was carried out using platinum plates (2 x 2 cm) as the working and counter electrodes, respectively. Polyaniline was synthesized by (1v).

At this time, the current density was about 9.8@A/c. The obtained polyaniline was thoroughly washed with distilled water and then thoroughly dried.

Next, this polyaniline was used as a positive electrode, and I? was used as a negative electrode. A lithium plate (2×4 [phase]) with a diameter of 1 mm was used, and the electrolyte contained 11 mol/J of L! A battery was constructed using a propylene carbonate solution of BF4, and battery experiments were conducted. That is, as a charge/discharge test, the positive electrode was charged with a current of IIIA until the potential difference with respect to the negative electrode became 4.1 V, and then discharged with a current of 1 m1/1 until the potential difference of the positive electrode with respect to the negative electrode became 2.8 V. repeated. As a result, the charge/discharge efficiency of the 10th cycle was 99%.
, the discharge capacity is 182 AI+ per 1 k(] of polyaniline
It's hot.

[Comparative Example 3] Polyaniline was synthesized in the same manner as in Example 2, except that a 2 mol/j aqueous perchloric acid solution was used instead of a 2 mol/j aqueous hydrochloric acid solution.

As a result of conducting a battery experiment using this polyaniline under the same conditions as in Example 2, the charge/discharge efficiency of the 10th cycle was 9.
6%, discharge capacity is 110Al+ per 1kg of polyaniline
Met.

[Example 3] Polyaniline synthesized under the same conditions as Example 1 was used as the positive electrode, graphite cloth (manufactured by Nippon Carbon Co., Ltd.) was used as the negative electrode, and L with a concentration of 1 mol/J was used as the electrolyte.
A battery was constructed using a propylene carbonate solution of i (JO4) and a battery experiment was conducted.The positive electrode and negative electrode were made to have approximately the same weight.For the charge/discharge test, the potential difference between the positive electrode and the negative electrode was 4.5V. 2Illl/1 until
Then, with the same current of <2 WA, the potential difference between the positive electrode and the negative electrode becomes 2. The operation of discharging was repeated until the voltage reached Ov. As a result, the discharge capacity in the fifth cycle was 170 Ah per 1 kGl of polyaniline.

Also, graphite cloth costs 184% per kg. A
h, and no generation of gentrite was observed on the negative electrode.

Applicant: Brideston Co., Ltd. Agent: Takashi Kojima, Patent Attorney: July 26, 1980 Manabu Shiga, Commissioner of the Patent Office1, Indication of the case: 1982 Patent Application No. 782602, Name of the invention: Secondary battery 3, Relationship with the case of the person making the amendment Patent W , polyaniline, etc.).

(2) “Dendrite” on page 7, lines 1 and 2
Correct that to "dendrites".

Written amendment to the above procedures (voluntary) April 25, 1985 Manabu Shiga, Commissioner of the Patent Office1, Indication of the case 1982 Patent Application No. 782602, Title of invention secondary battery3, Person making the amendment Case Relationship with Patent Applicant Representative Irie Akira Daha Create Building 5th Floor Telephone (54,5) 64546
, Contents of the amendment (1) Insert the legal text on a new line after "ta." on page 14, line 15 of the specification.

r [Example 4] Polyaniline synthesized under the same conditions as Example 1 was used as the positive electrode, and an electrochemically prepared lithium-aluminum alloy (AIll, .Llo, s) was used as the negative electrode. constructed a battery using a propylene carbonate solution of LiCΩ04 with a concentration of 1 mol/ρ, and conducted battery experiments. Note that the positive electrode and the negative electrode had approximately the same weight. As a charge/discharge test, the positive electrode was charged with a current of 2 mA until the potential difference between the positive electrode and the negative electrode became 4.2 V, and then the potential difference between the positive electrode and the negative electrode was changed to 2.2 V with the same current of <2 mA.
The operation of discharging was repeated until it became 0 ■. As a result, the discharge capacity in the fifth cycle was 170 Ah per 1 kg of polyaniline. Further, it was 177 Ah per 1 kg of lithium-aluminum alloy, and no formation of dendrites or the like was observed in the negative electrode. j or more

Claims (1)

[Scope of Claims] 1. A secondary battery formed from a positive electrode, a negative electrode, and an electrolyte, characterized in that the positive electrode contains polyaniline electrolytically synthesized in a hydrochloric acid solution as an active material. 2. The secondary battery according to claim 1, wherein the negative electrode contains as an active material a material capable of reversibly transferring cations in and out between the negative electrode and the electrolyte. 3. The secondary battery according to claim 2, wherein the negative electrode contains graphite as an active material. 4. The secondary battery according to any one of claims 1 to 3, wherein the electrolyte is dissolved in a nonaqueous solvent.