JPS6293862A - Secondary battery using polyaniline for electrode material - Google Patents

Abstract

PURPOSE:To offer such a secondary batter that is large in discharge capacity, by using polyaniline having a fibril structure of less than the specified value in mean diameter for the positive pole. CONSTITUTION:Polyaniline having a fibril structure of less than 0.5mum in mean diameter is used for the positive pole. A secondary batter to be secured by this method is larger in maximum discharge capacity than any other secondary batter using polyaniline of no fibrin structure or if being the fibril structure, such polyaniline as being thick in the mean diameter, and it has the maximum discharge capacity of more than 550mc/mg and, what is more, its charge and discharge cycle characteristic is very good, thus it comes to a useful secondary battery.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application The present invention relates to a secondary battery using polyaniline having a fibril structure as an electrode material.

<Prior art> In recent years, starting from the development of metal conductivity by doping polyacetylene thin films, it has been possible to improve the S properties by doping various conjugated polymer compounds with appropriate electron acceptors and electron donors. Attempts have been made, and in the process electrochemical doping methods have been developed. At the same time, it was discovered that a battery could be constructed by using a polyacetylene thin film electrochemically doped with electrolyte ions as the electrode material and a suitable redox electrode as the counter electrode, and that it could be recharged. discovered (Japanese Unexamined Patent Publication No. 56-18
6469). However, polyacetylene thin films are easily oxidized and unstable to water and oxygen.

There is a demand for materials with excellent oxidation resistance.

<Problems to be solved by the invention> Recently, polyaniline has attracted attention as a material with excellent oxidation resistance, and attempts have been made to create secondary batteries using film or powdered polyaniline as the positive electrode. Chemistry, Vol. 53, No. 8, pp. 592-596 (
(1985)).

However, the release capacity of this secondary battery is limited to practical secondary batteries.
It was not necessarily sufficient to form a pond.

An object of the present invention is to provide a secondary battery that uses polyaniline as a positive electrode and has a large discharge capacity.

<Means for solving the gap between points> The present invention uses polyaniline having a fibril structure with an average diameter of 0.5 μm or less as a positive electrode.The secondary center of gravity is 550 mC/
Eel release more than mfi' ↑t! It was discovered that the battery has a good capacity and a good charge/discharge cycle.

The present invention will be explained in detail below.

Average 1r of fibrillar polyaniline used in the present invention
The t diameter is 0.5 μm or less, preferably O, a μm or less, and more preferably 0.2 μm or less.

The fibrillar polyaniline used in the present invention is obtained by electrolytic oxidation polymerization of aniline in an acidic aqueous solution containing aniline.

For reaction solution, the aniline concentration is 0.2 mol/! that's all,
Preferably, the acid concentration is 0.4 mol/1 or more and 1.9 mol/j or less, and the acid concentration is 0.2 mol/1 or more, preferably 0.2 mol/1 or more and less than 2.0 mol/1, and more preferably 0.5
An acidic aqueous solution containing aniline with a concentration of mol/l or more and 1.9 mol/l or less is used.

The acid is stable under the conditions of electrolytic oxidative polymerization of aniline, forms a salt with aniline, and dissolves aniline in an aqueous solution, so any acid may be used, specifically perchloric acid, periodic acid, Examples include sulfuric acid, hydrochloric acid, hydrobromic acid, hexafluorophosphoric acid, para-toluenesulfonic acid, and methanesulfonic acid. ) As the electrolytic oxidation polymerization method, a constant current method, a constant m-position method, a constant voltage method, a fixed potential method, etc. can be used. In the case of the constant current method, the electrolytic oxidation polymerization current density used is Q, 1 mA/d to 1000 mA#, preferably 1 mA/ad to 1 OmA/c4, more preferably 8 mA/d to 1QmA/d.

In the case of the constant potential method, the anode m position is set at a voltage of 0.8 V to 2. OV, good tL, < +, to
, sv~i, 5 V, Sara lC good * L, < Ha0.8
V ~1. OV. The electric power required for electrolytic oxidative polymerization is Q, IC/cj to 1000C/cII11, preferably IC/- to 100C/ci, more preferably 8C
/d~IOC/d.

As the anode used in electrolytic oxidative polymerization, materials that do not react during the reaction, such as platinum, gold, titanium, carbon materials, indium-tin, etc., can be used, but platinum, gold, and carbon materials are preferable. Particularly preferred is a polyester film deposited with. The temperature during electrolytic oxidation polymerization is within the range where the reaction solution is liquid, that is, the freezing point amount,
h [Can be done with 8 points or less, but usually 1000-9
It is 0°C.

As the dopant for the polyaniline controlling the fibril structure, those used in general conjugated commercial molecular compounds such as polyacetylene can be effectively used. Specifically, PF5- and 5bF6- are halogen compound anions.

AsFa-, I-, Br-, C/-, I3-, 'BF
4-, AlIC/4-, etc., C which is a perhalogen acid ion
CF3SO3 which is an organic sulfonic acid ion such as lO4-
-, CH3 and -8O.

Examples include CH35O3-, 504, N0a-, and the like. Actually, WWJI! salt containing these! Used as an i quality.

Specific examples of these include LiPF6. LiSbF6
゜LiAsF6. LiClO4, NaI, NaP
F6. NaSbF6゜NaAsF5, NaClO
4, KI, KPF6, KSbFa.

KAsFa, KClO4, (: (n-Bu)4N
”) (AsF6-).

((n-Bu)4N") (PFa-), ((n-
Bu)4N'') (C104-).

Zn504 etc. are exemplified. These m solutes may be used alone or in combination of two or more.

As a negative electrode, L: L, Na, K, Mlg, Ca,
Pb.

Examples include metals such as Zn and AI, alloys thereof, conjugated polymeric compounds such as polyacetylene, polyparaphenylene, polyparaphenylene vinylene, and their derivatives, and carbon-based materials such as carbon fiber and graphite, but are not necessarily limited to these. It is not something that will be done.

The structure of the secondary pond that can be used in the present invention is polyaniline (
Anion doping)/1! Solute/conjugated polymer (cation doping), polyaniline/alkali metal salt m solute/alkali metal or aluminum alkaline earth alloy,
Polyaniline/Electrolyte/Carbon-based material (both ion doping), Polyaniline/Tunedolyte/Activated gold FA4 electrode (P'
b, Zn, etc.), but are not necessarily limited to these.

As for the form of the electrode, polyaniline having a fibrillar PR structure deposited on the Wl electrode in an electrolytic solution may be used as it is as a positive electrode, it may be composited with a carbon-based material, or it may be made of a conventionally known conjugated polymer such as polyacetylene. It is possible to use a similar shape to the electrode used. In particular, since the polyaniline used in the present invention has an extremely large aspect ratio, it has excellent moldability and can be easily combined with carbon materials.

The solute medium does not need to be a body as long as the electrochemical transfer of the dopant is possible, and a solid medium such as an inorganic or organic solid tUH material can also be used.

Generally, it is normally used as an electrolyte. Here, the solvent (medium) for the electrolyte can be water or an organic solvent, and is not particularly limited.

As the organic solvent, an aprotic organic solvent having a high hexagonal rate is preferable, and specifically, propylene carbonate,
Tetrahydrofuran, 1,2-dimethoxyethane, sulfolane, 3-methylsulfolane, dichloroethane, r-
Examples include, but are not limited to, butyrolactone, dimethylsulfoxide, dimethylformamide, dioxolane, acetonitrile, benzonitrile, nitromethane, dimethylacetamide and the like. These organic solvents may be used alone or in combination of two or more.

IIL solution: There is no limit to the electrolyte concentration during the night, and it is limited depending on the type of electrolyte used and the type of cancer vector, but usually it is preferably 0.001 to 10 mol/j, and 0.01 to 10 mol/j.
2 mol/l is more preferred.

<Examples> The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples in any way.

Example 1 imol/jHC104 containing 0.5mol/l aniline
Electrolytic oxidation polymerization was carried out using an aqueous solution as a reaction solution and a platinum plate as an anode and a cathode at an anode current density of 5 mA/d for 20 minutes. After washing the polyaniline deposited on the anode with water,
Dry.

A secondary battery was constructed by using the obtained polyaniline deposited on a platinum plate as a positive electrode, a lithium piece as a negative electrode, and propylene carbonate containing 1 mole of LiClO4 as an electrolyte.

This secondary battery was charged and discharged at a constant current in an argon atmosphere. At this time, the charging/discharging current density is 0.2 mA/d
Te has a maximum discharge capacity of 58 mQ/''? based on the weight of polyaniline excluding Dohant Teal ClO4-.Also, the charge/discharge current density is 8 [592 m for IA/cj].
The maximum discharge capacity was c/li. Also full of air stirring 550
mc/#? Assuming that charging and discharging at 0.2111A/d is 50
When repeated several times, the coulomb efficiency was approximately 100 cm and no deterioration was observed. After the completion of charging and discharging, this polyaniline was observed using a scanning electron microscope, and as shown in FIG. 1, it was found to be in the form of fibrils with an average diameter of 0.2 μm.

In addition, the maximum number in the following examples and comparative examples is 141 W4
As in Example 1, At was calculated based on the weight of polyaniline containing no dopant.

Example 2 The same cathode as in Example 1, m#2, was used, except that a gold-deposited polyester film was used as the anode, and the anode current density was 5 mA/
Electrolytic oxidation polymerization was performed using AI for 25 minutes. The polyaniline deposited on the anode was washed with water and dried.

When a secondary battery was constructed using this polyaniline as a positive electrode and charged and discharged in the same manner as in Example 1, the charge and discharge current density was 648 mA/cj and 4 mA/d, respectively.
The maximum discharge capacity was me/πl and 67211flC/l19. This polyaniline has an average diameter of 0.2μ
It was fibrillar in shape.

Example 3 Silver/silver chloride ratio 80 at a constant potential of 0.9■ with respect to the pole to the aperture f
Preaniline was obtained in the same manner as in Example 2, except that minute electrolytic acid polymerization was performed.

When a secondary battery was constructed using this polyaniline as a positive electrode and charged and discharged in the same manner as in Example 1, the maximum discharge capacity was 620 at a charging and discharging current density of 0.2 mA/ci.
mc/~ was shown. In addition, the average diameter of this lianiline is 0.
．． It was in the form of fibrils of 2 μm.

Comparative Example 1 1 mol/j IC104 containing 0.1 mol/l aniline
Polyaniline was obtained in the same manner as in Example 2 and @J, except that water was used as the reaction solution and the reaction was carried out at an anodic current density of 95 mA/d for 20 hours.

A secondary battery was constructed using this polyaniline in the same manner as in Example 1, and charging and discharging were performed.
Maximum discharge capacity is 451 at 0.2 mA/ci
It was only mc/■.

As shown in Figure 2, this polyaniline has an average diameter of 0.
．． It had a fibrillar shape of 7 μm.

Comparative Example 2 xMorph tHcz aqueous solution 9100 g+? A solution prepared by dissolving NH4) 232082.89 in 10 wt of water was added and stirred at room temperature for 1 hour. Thereafter, the resulting precipitate was separated from P, washed with water, and dried under reduced pressure to obtain a dark blue polyaniline powder. This polyaniline was an aggregate of particles as shown in FIG. A secondary battery was constructed in the same manner as in Example 1, except that this polyaniline was pressure-molded to form a pellet, and the lead was taken by pressing it onto a platinum mesh.Charging and discharging were performed. 0
．． At 2 mA/cd, the maximum discharge capacity was only 781110/η.

<Effects of the Invention> As shown in the Examples and Comparative Examples above, the secondary battery according to the present invention is superior to a secondary battery using polyaniline that does not have a fibril structure or polyaniline that has a large average diameter even if it has a fibril structure. The maximum discharge capacity is also large 5
It has a maximum discharge capacity of 50 mc/η or more, and also has good charging/discharging chamber cycle characteristics, making it a useful secondary battery.

[Brief explanation of drawings]

FIG. 1 is a photograph taken using a scanning electron microscope of polyaniline used in Example 1, and FIGS. 2 and 3 are photographs taken in Comparative Examples. The magnification is 10,000 times, and the length of one solid line at the bottom corresponds to 1 μm. Procedural amendment (method) % formula % 1. Indication of the case 1985 Patent Application No. 233002 2. Name of the invention Secondary battery using polyaniline as electrode material 3. Person making the amendment Relationship to the case Patent applicant address 5-15 Kitahama, Higashi-ku, Osaka Name (20
9) Sumitomo Chemical Co., Ltd. 5. Date of amendment order: January 28, 1985 (shipment date) 6. "Brief explanation of drawings" column 7 of the specification subject to amendment, Part 12 of the statement of contents of the amendment Page lines 17-20 “Figure 1 is Example-1-
-------------1...-1 μm. "Figure 1 is a photograph taken by a scanning electron microscope showing the shape of the polyaniline fibers used in Example 1,
Figure 2 is a scanning electron microscope photograph showing the shape of the polyaniline fibers used in Comparative Example 1, and Figure 3 is a scanning electron microscope photograph showing the particle structure of the polyaniline used in Comparative Example 2. All 0 multipliers are 10
．． 000 times, and the length of one solid line at the bottom corresponds to 1 μm. ” is corrected. that's all

Claims (1)

[Claims] A secondary battery characterized in that polyaniline having a fibril structure with an average diameter of 0.5 μm or less is used as a positive electrode.