JPS59226022A - Electrically conductive material and its production - Google Patents

Abstract

PURPOSE:To provide an electrically conductive material consisting of essentially amorphous powdery polypyrrole or poly-N-alkylpyrrole doped with a dopant, and having high electrical conductivity and suitable as an electrode of battery, semiconducltor element, etc. CONSTITUTION:An essentially amorphous powdery polypyrrole or poly-N-alkylpyrrole (abbreviated as polypyrrole) doped with a dopant comprising the ion of supporting electrolyte (e.g. lithium tetrafluoroborate): and an electrically conductive material composed of an essentially amorphous powdery polypyrrole obtained by the electrochemical polymerization and the simultaneous doping (prefferably under a potential of <=3.5V in a solvent such as acetonitrile) of pyrrole or N-alkylpyrrole using copper or a metal baser than copper (e.g. iron, tin, stainless steel, Ni, etc.) as anode.

Description

[Detailed description of the invention] The present invention relates to a conductor and a method for manufacturing the same.

Specifically, ν using pyrrole or N-alkylpyrrole
``Regarding standard electrical conductors and their manufacturing methods.

Conventionally, conductors made from pyrrole were prepared by preparing a solution of pyrrole and a doping agent in a solvent, then adding platinum and
Electrically conductive polypyrrole is obtained by dipping an electrode made of a noble metal such as gold, electrochemically polymerizing it, and doping it.

However, polypyrrole obtained by the conventional method using a noble metal electrode is obtained as a film-like polymer having a crystalline portion of about -04 or more on the anode. However, conventional film-like polypyrrole has the disadvantage that it is difficult to powder due to its form and can only be used for limited purposes. Ta.

In order to eliminate the drawbacks of the conventional polypyrrole conductor, the present inventors have conducted intensive studies and found that if copper or a material less base than copper is used as the anode material, polypyrrole can be formed in powder form instead of in film form. It was discovered that this can be obtained directly on the anode, leading to the completion of the present invention.

That is, the gist of the present invention is to use powdered amorphous polypyrrole or poly-N-alkylpyrrole doped with a doping agent and copper or a material less base than copper as an anode,
The present invention relates to a method for producing a conductor made of powdery amorphous polypyrrole or polypyrrole or poly-N-alkylpyrrole, which comprises electrochemically polymerizing pyrrole or N-alkylpyrrole and simultaneously doping the same.

Electrochemical polymerization in the present invention is carried out as follows.

Pyrrole or N-alkylpyrrole (hereinafter abbreviated as "pyrrole") and a supporting electrolyte are dissolved in a solvent and placed in a reaction vessel.An anode and a cathode are immersed in this, and a potential difference is applied between the two electrodes. A specific polymerization reaction is carried out.

Doping occurs simultaneously with the polymerization reaction, and doped polypyrrole or poly-N-alkylpyrrole (hereinafter abbreviated as r-polypyrrole) is obtained as a powder. If this reaction is shown as a chemical formula using pyrrole as an example, the formula (1) is as follows)
It is.

n convex na It is an alkylpyrrole. The alkyl group is 0. ~aai is a straight chain or branched alkyl group. It is preferable to use a colorless and transparent monomer that has been vacuum distilled to remove impurities immediately before the polymerization reaction.

The monomer solution concentration during polymerization is O1θ/mol/Il
Preferably θ between /, omoVl, 0.7 mo
It is between Vi and 002m0V.

As the anode material used in the present invention, copper, a metal less base than copper, or an alloy containing these metals is used. A metal less base than copper means a metal whose standard electrode potential (about θJ2V in the case of copper) is smaller than that of copper. Specifically, they include copper, iron, tin, nickel, stainless steel, etc.

The solvent used in the present invention has a high dielectric constant, that is, S
, O or more, preferably 30 or more, such as acetonitrile, (relative permittivity Jt, s) propylene carbonate (AQ
, lI), γ-butyrolactone (J?), N, N-
Dimethyl, formamide (A;, 2./), dimethyl sulfoxide (d14 g), N-methylpyrrolidone (3, o) nitromethane (,? left, g?)
, tetrahydrofuran (t, !rg), etc., and acetonitrile and propylene carbonate are particularly preferred. Preferably, the solvent is distilled to remove impurities before use.

In addition, in the present invention, in order to increase the electrical conductivity of the solvent, 0. /~3w/w water in solvent (relative dielectric constant 7LJ9)
may exist.

The present invention uses a supporting electrolyte as a doping agent.

The supporting electrolyte is an organic or inorganic salt or double salt that is soluble in an organic solvent and easily ionically dissociated. Examples of these include lithium tetrafluoroborate, lithium perchlorate, tetrabutylammonium tetrafluoroborate, te)laethylammonium perchlorate, and triphthylammonium m-nitrobenzenesulfonate. It is preferable that these supporting electrolytes be thoroughly dried under vacuum before use. The solution concentration of supporting electrolyte is 0
．． 0/mol/ll to/, between OmoVi3, preferably □, 0.2 m from o s rnoyi
oVll.

The ions of the supporting electrolyte function as a doping agent, and the conductor of the present invention is obtained.

The reaction temperature in the present invention may be any temperature between the freezing point and the boiling point of the solvent, but it is usually carried out at room temperature.

If the potential difference applied between the anode and the cathode in the electrochemical polymerization reaction of the present invention is too large, problems such as decomposition of the solvent will occur, so it is preferably 10V or less, preferably tV or less.
It is 3v or less.

The polymerization reaction can be carried out by any method such as a constant current method or a constant current method.

The doped polypyrrole obtained in the present invention is a black to dark colored powder and is substantially amorphous. Amorphous is essentially crystallinity! Refers to those below the section. According to elemental analysis, the composition of the l unit is usually 04 Hs
NlXa. (However, O, S≧a≧0./), this indicates that pyrrole undergoes dehydrogenative polymerization and is doped with [a mole of dopant per monomer/unit]. The product was determined by X-ray diffraction to be substantially IO
It has been confirmed that it is θ-coupled amorphous.

The electrical conductivity of this product was measured using the four-terminal method, /θ
It has good electrical conductivity between 1 and 0 = Ω-'cIrL-', and by adding it to insulating polymers, it can quickly impart electrical conductivity to these polymers.

Furthermore, since it is a fine powder, it can be pressure-molded into any shape and size, so it can be advantageously used for applications such as secondary battery electrode materials and semiconductor devices.

On the other hand, the product li obtained by the conventional method of using noble metals such as platinum and gold as the anode material is a uniform and dense film-like polypyrrole sb, which has a crystallinity of approximately 20% or more, It is difficult to pulverize and has only extremely limited uses.

The present invention will be further explained below with reference to Examples, but the present invention is not limited to the following Examples unless the gist of the invention is exceeded.

Example/Into a 200 ml separable flask are placed pyrrole of 00 and θy, 3.301 of tetrabutylammonium borohydride, and /θθml of acetonitrile. In this solution, a stainless steel plate (SUS, ?/A) of 0.0 cm x 30 x o-oscm was used as an anode and a 0.0 cm x 30 x o-oscm stainless steel plate (SUS, ?/A) was used as a cathode. A; (HX/α
x o, θ/I soaked my platinum plate, connected the stainless steel plate to the positive electrode of a constant voltage power source with a platinum wire, connected the platinum plate to the negative electrode of the same power source with a platinum wire, replaced the reaction system with nitrogen, and 1 at θV
Electrochemical polymerization was carried out by applying current for 20 hours.

Black powder of θ, -I was obtained near the anode. Elemental analysis of this product revealed that when normalized to carbon MIG, its l unit composition was 04Hs, *oN+, a.

(BF,). 0.2, pyrrole undergoes dehydrogenation polymerization,
5 fluoroborate ion per virol l unit is 0. ．． It showed that it was doped with 32 moles.

When this product was subjected to X-ray diffraction, it was found to be ioo% amorphous. The electrical conductivity of a pressure-molded powder product measured by the four-probe method was 7Ω-'cm-'.

Reference Example/Example/The stainless steel of the anode plate in Example/ was changed to a film made of vaporized gold, but electricity was applied in the same manner as in Example 1, and electrochemical polymerization was performed. A black, uniform, dense film with a buoyancy was obtained. The composition of this film is 04Hm-+aN1.64 (BF4)+10w
It was e. X-ray diffraction of this film-like polypyrrole showed that the product had about 30% crystallinity. What is the electrical conductivity of this film? , ArX 10
It was 'Ω-'crrL-'.

Example λ Electrification was carried out in the same manner as in Example 1, except that the stainless steel of the anode plate in Example/ was changed to a copper plate, and the supporting electrolyte, tetrabutylammonium tetralyloborate, was changed to lithium tetralyloborate. When electrochemical polymerization was carried out, a black precipitate was obtained. The composition of this l unit is 0
*HhuN14t(BFa)os+. X
5aih io.

It was shown that it was amorphous. The electrical conductivity of a molded article of this powder product was 7°OX/Q=Ω-"cm-'.

Sender: Mitsubishi Chemical Industries, Ltd. Representative Patent Attorney Hase - (7 others)

Claims (2)

[Claims] (1) Powdered, substantially amorphous polypyrrole or bo! doped with a doping agent. A conductor made of J-m-alkylpyrrole. (2) Powdered, substantially amorphous polypyrrole or hapo IJ-N- in which pyrrole or N-alkylpyrrole is electrochemically polymerized using copper or a material baser than copper as an anode, and is doped at the same time. A method for producing a conductor made of alkylpyrrole.