JPS62149724A - Production of polyaniline - Google Patents

Abstract

PURPOSE:To obtain polyaniline having a large discharge capacity and being useful as an electrode material for cells, photocells, etc., by subjecting polyaniline to reduction treatment and/or alcohol treatment. CONSTITUTION:Polyaniline obtained by, e.g., an electrolytic polymerization process is subjected to electrolytic reduction treatment for 3-2,500min at a current density of 0.1-80mA/cm<2>, and then subjected to chemical reduction by immersing in a 5-20wt% aqueous hydrazine solution for 10-1,500min or is subjected to alcohol treatment by immersing in a 30wt% or higher solution of an alcohol such as methanol for 5min-24hr at 10-40 deg.C.

Description

[Detailed Description of the Invention] The present invention relates to a method for producing polyaniline that can produce polyaniline suitable as an electronic material, particularly polyaniline that has a large discharge capacity when used as an electrode material for batteries and photovoltaic cells. Regarding.

I'm trying to do the traditional 1' nete and daily power check. Title 1: In recent years, polyaniline has been attracting attention as a new electronic material in application fields such as batteries, photovoltaic cells, electrochromic displays, and various modified electric scrapers. It's thriving. As a result, polyaniline synthesized in an alkaline solution is electrochemically inactive, and electrochemically active polyaniline can be obtained by oxidative polymerization of aniline in an acidic aqueous solution such as sulfuric acid. Among polymerization methods, electrolytic oxidation (electrolytic polymerization) is superior to chemical oxidation methods using chemical oxidants such as persulfates in terms of energy density (discharge current and discharge voltage) and productivity as various electrode materials. ) method has been found to be superior.

In addition, the applicant found that post-treatment such as immersing polyaniline in dimethylformamide and eluting and removing the dimethylformamide-soluble portion improves durability when used as an electronic material, and We have already proposed polyaniline consisting of (
(Japanese Patent Application No. 60-202223).

As mentioned above, attempts have been made to improve the suitability of polyaniline as an electronic material by not only improving its production method, that is, the polymerization method, but also by improving the post-treatment of the polymer obtained by polymerization.

On the other hand, when polyaniline is applied to electronic materials, it is required to further improve its properties as an electronic material such as durability.In particular, when polyaniline is used as an electrode material for batteries, photovoltaic cells, etc. In order to extend the service life, it is desired to further increase the discharge capacity.

The present invention has been made in view of the above circumstances, and provides a method for producing polyaniline that can produce polyaniline suitable as an electronic material, particularly a polyaniline with a large discharge capacity when used as an electrode material for batteries, photovoltaic cells, etc. The purpose is to provide a processing method.

The present inventors,
As a result of extensive research into post-processing methods for polyaniline that could improve its suitability as an electronic material, particularly its discharge capacity when used as an electrode material for batteries, photovoltaic cells, etc., we conducted a reduction treatment on polyaniline and In addition to or instead of reduction treatment, if alcohol treatment is performed by immersion in alcohol such as methanol,
The present invention was based on the discovery that the discharge capacity is significantly increased compared to polyaniline which is not subjected to such treatment, and the above object is effectively achieved.

Therefore, the present invention provides a method for producing polyaniline, which is characterized by subjecting polyaniline to reduction treatment and/or alcohol treatment.

The present invention will be explained in more detail below.

The method for producing polyaniline according to the present invention involves subjecting polyaniline to reduction treatment and/or alcohol treatment as described above. In this case, there are no restrictions on the method of obtaining polyaniline subjected to such treatment, and polyaniline obtained by chemical polymerization, electrochemical polymerization, etc. can be used, but electrolytic polymerization, especially hydrochloric acid Alternatively, polyaniline obtained by electrolytically oxidizing aniline using borofluoric acid is preferably used.

In the present invention, the reduction treatment method includes a method of immersing polyaniline in a solution of borofluoric acid, hydrochloric acid, perchloric acid, sulfuric acid, phosphoric acid, nitric acid, etc. and electrolyzing the polyaniline with the polyaniline as a cathode, and/or chemical reduction treatment. The method will be adopted.

As for the conditions for the electrochemical reduction treatment, it is advantageous to apply a reverse potential that is lower than the potential required to obtain polyaniline by the electrolytic polymerization method, and is 0.1 to 80 mA/cn!
, in particular it is preferable to carry out the electrolysis at a current density of 1 to 5 mA/ant, for example 1 mA/cII
It is preferable to perform the reduction at a rate of about 0.30 to 0.42 C/■ at a constant current of t. In addition, the electrolysis time is 3 to 2500
The heating time is preferably about 50 to 250 minutes, and the electrolytic solution can be heated if necessary, but room temperature is usually sufficient.

Chemical reduction treatment methods include exposing polyaniline to a reducing atmosphere such as hydrogen gas or immersing it in a solution containing a reducing agent such as hydrazine. A method of immersion in an aqueous solution is preferably employed. In addition, the processing time is 10~
The heating time is preferably 1500 minutes, preferably 180 to 720 minutes.

On the other hand, as a method for treating polyaniline with alcohol according to the present invention, any method can be adopted as long as it brings polyaniline and alcohol into contact with each other, such as a method of immersion in a liquid containing alcohol, a method of immersion in alcohol vapor, etc. Examples include a method of exposing the polyaniline to alcohol, a method of spraying alcohol onto polyaniline, and the like. Among these, the method of immersing the polyaniline in a liquid containing alcohol is advantageous, and when treating polyaniline by immersing it in a liquid containing alcohol, the polyaniline is immersed in the liquid containing alcohol for 5 minutes to 24 hours.
It is particularly preferable to soak for 30 minutes to 2 hours. Note that the treatment temperature is preferably 10 to 40°C, particularly 15 to 30°C. In this case, alcohol-containing liquids include aliphatic alcohols such as methanol, ethanol, propatool, butanol, pentanol, hexanol, heptatool, ethylene glycol, and glycerin;
If the liquid contains compounds with alcoholic hydroxyl groups such as aromatic alcohols such as Hensyl alcohol and derivatives of these alcohols, a high-purity alcohol liquid consisting of one or more of these types, or a combination of alcohol and water, etc. Mixing with solvents such as acetone, diethyl ethyl, toluene, etc.? 8? (Although any liquid may be used, a liquid containing alcohol at 30% by weight or more, especially 85% by weight or more is preferable. In particular, the above-mentioned high-purity alcoholic liquids, especially aliphatic alcohols, especially methanol, ethanol, and these Mixed alcoholic liquids are preferably used.

In the present invention, polyaniline is subjected to the above-mentioned reduction treatment and alcohol treatment, and in the present invention, only one of these treatments may be performed (or both treatments may be performed). However, from the point of view of discharge capacity, it is preferable to perform both treatments.In this case, both treatments may be performed separately, or both treatments may be performed simultaneously by performing electrolysis in an alcohol-containing solution. In addition, when both treatments are performed separately, it is possible to adopt a method in which alcohol treatment is first performed and then reduction treatment is performed, but a method in which alcohol treatment is performed after reduction treatment is preferable. In the invention, in addition to the above treatments, other treatments such as washing with water or an organic solvent such as acetone or dimethylformamide can be performed, and after electrochemical reduction treatment, chemical reduction treatment can be performed. Or, after washing with water, acetone, dimethylformamide, etc. without applying any treatment, or after applying chemical reduction treatment,
Although it is possible to perform an alcohol treatment, the most preferable method is to perform an electrochemical reduction treatment and then a chemical reduction treatment and/or an alcohol treatment. This is a method in which alcohol treatments are performed sequentially.

Mitsunori ■4 As explained above, the present invention produces polyaniline by subjecting polyaniline to reduction treatment and/or alcohol treatment, thereby producing polyaniline suitable as an electronic material, particularly for use as an electrode material for batteries, photovoltaic cells, etc. In this case, polyaniline with a large discharge capacity can be obtained.

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 electrolyte solution consisting of 75 cc of aniline, 15 cc of 42% porium, and 30 cc of ion-exchanged water was applied to an area of 4
The mixture was placed in an electrolytic bath equipped with a working electrode and a counter electrode made of cal platinum plates, and electrolytically polymerized by applying current at a constant current of 20 mA for 1.4 hours to obtain polyaniline.

Furthermore, for this polyaniline, 4
The sample was electrochemically reduced with a reverse current of mA for 1 hour, and then immersed in a 10% aqueous solution of hydrazine 1 permanent for 12 hours to perform reduction treatment with a reducing agent. After that,
The obtained polyaniline was immersed in methanol for 12 hours and then vacuum dried to produce about 36 mg of the polyaniline of Example 1.

Next, the above polyaniline was used as a battery electrode plate, lithium was used as a counter electrode, and 1 mol of LiBF4/propylene carbonate was used.
/e was used as an electrolyte to construct a battery.

Using this battery, the polyaniline electrode plate was charged at a constant current of 0.5 mA until the voltage reached 4 V compared to lithium, and then discharged at a constant current of 0.5 mA until the voltage reached 2 V compared to lithium. Capacity density is 170A
It was H/kg.

[Example 2] In the method for producing polyaniline in Example 1, the reduction treatment using a reducing agent was omitted, and after the electrochemical reduction treatment, washing was performed with ion-exchanged water, and then treatment with methanol was performed. Approximately 41 mg of polyaniline was produced in the same manner as the production method.

A battery was constructed using this polyaniline in the same manner as the polyaniline of Example 1, and the discharge capacity density of the resulting battery was measured, and the discharge capacity density was 141 Ah/kg.

[Example 3] The method for producing polyaniline in Example 1 was repeated except that the methanol treatment was omitted, and after the electrochemical luminescence treatment, washing was performed with ion-exchanged water, and then the reduction treatment with a reducing agent was performed, followed by vacuum drying. Approximately 36 cubic centimeters of polyaniline was produced in the same manner as in Example 1 for producing polyaniline.

A battery was constructed using this polyaniline in the same manner as the polyaniline of Example 1, and the discharge capacity density of the resulting battery was measured, and the discharge capacity density was 149 AH/kg.

(Example 4) Approximately 41 mg of polyaniline was produced in the same manner as in Example 2, except that ion-exchanged water washing treatment was performed instead of methanol treatment.
of polyaniline was produced.

A battery was constructed using this polyaniline in the same manner as the polyaniline of Example 1, and the discharge capacity density of the resulting battery was measured, and the discharge capacity density was 125 AH/kg.

[Example 5] About 41 cm of polyaniline was produced in the same manner as the polyaniline production method of Example 2, except that acetone washing was performed instead of methanol treatment.

A battery was constructed using this polyaniline in the same manner as the polyaniline of Example 1, and the discharge capacity density of the resulting battery was measured, and the discharge capacity density was 125 AH/kg.

[Example 6] Approximately 41 ml of polyaniline was produced in the same manner as the polyaniline production method of Example 2, except that DME (dimethoxyethane) washing was performed instead of methanol treatment. .

A battery was constructed using this polyaniline in the same manner as the polyaniline of Example 1, and the discharge capacity density of the resulting battery was measured, and the discharge capacity density was 125 A H/kg.

[Comparative Example 1] An electrolyte solution consisting of 5 cc of aniline, 15 cc of 42% borofluoric acid, and 30 cc of ion-exchanged water was applied to an area of 4
It was placed in an electrolytic cell equipped with a working electrode and a counter electrode made of a CNI platinum plate, and electrolytically polymerized by applying current at a constant current of 20 mA for 1.4 hours. After washing with ion-exchanged water and vacuum drying, it was
① Polyaniline was produced.

Next, the above polyaniline was used as a battery electrode plate, lithium was used as a counter electrode, and LiBFa/propylene carbonate l mo
A battery was constructed using 1/1- as the electrolyte.

Using this battery, the polyaniline electrode plate was charged at a constant current of 0.5 mA until it reached 4 V vs. lithium, and then at a constant current of 0.5 mA until it reached 2 V vs. lithium.
When discharging was carried out at a constant current, the discharge capacity was 105A.
h/kg.

[Comparative Example 2] Comparative Example 1 except that the polyaniline manufacturing method of Comparative Example 1 was washed with acetone instead of washing with ion-exchanged water.
Approximately 50 Akebono's polyaniline was produced in the same manner as the method for producing polyaniline.

A battery was constructed using this polyaniline in the same manner as the polyaniline of Comparative Example 1, and the discharge capacity density of the resulting battery was measured, and the discharge capacity density was 105 Ah/kg.

[Comparative Example 3] About 40 nw of polyaniline was produced in the same manner as the method for producing polyaniline in Comparative Example 1, except that washing was performed with DMF (dimethylformamide) instead of washing with ion-exchanged water. Manufactured.

A battery was constructed using this polyaniline in the same manner as the polyaniline of Comparative Example 1, and the discharge capacity density of the resulting battery was measured, and the discharge capacity density was 105 Ah/kg.

Claims (1)

[Claims] A method for producing polyaniline, which comprises subjecting polyaniline to reduction treatment and/or alcohol treatment.