JP2762779B2 - Capacitor and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor using a conductive polymer layer as an electrode and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, with the digitization and miniaturization of circuits such as electric equipment, there has been a strong demand for capacitors used in circuits to have low impedance in a high frequency range, and to be small and have a large capacity. It has become. Under such circumstances, development of large-capacity capacitors using a conductive solid as an electrode has been actively conducted.

Conventionally, a tantalum solid electrolytic capacitor using manganese dioxide as an electrode has been well known, but a sufficiently low impedance in a high-frequency region cannot be obtained due to the high resistance of manganese dioxide. In addition,
As a solid electrolytic capacitor, instead of a manganese dioxide layer, an organic semiconductor with high conductivity and excellent anodic oxidation,
The use of 7,7,8,8-tetracyanoquinodimethane complex salt (TCNQ salt) for the cathode has been proposed. However, when the TCNQ salt is applied, an increase in specific resistance occurs, and the anode metal foil is used. There was a problem that the adhesiveness with the adhesive was poor.

Therefore, recently, a conductive polymer layer containing an anion of a supporting electrolyte as a dopant has been used as an electrode by electrolytic polymerization using a solution containing a heterocyclic compound monomer such as pyrrole or thiophene and a supporting electrolyte. There has been proposed a solid electrolytic capacitor used as a capacitor.

[0005] More recently, not only solid electrolytic capacitors but also polyimides electrodeposited on metal surfaces have been used as dielectrics.
A non-polar capacitor using a conductive polymer laminated thereon as an electrode has been proposed (Abstracts of the 58th Annual Meeting of the Electrochemical Society, pages 251 and 252). Electrolytic polymerized conductive polymers have higher electrical conductivity than the above-mentioned TCNQ salts, and can easily produce films having excellent adhesiveness. Therefore, capacitors using conductive polymers as electrodes have been particularly attracting attention.

[0006]

However, when a conductive polymer is left at a high temperature for a long time, various properties such as electrical conductivity, mechanical strength and adhesiveness are generally deteriorated, and the conductive polymer is used as an electrode. The capacitor also has a problem that its characteristics are deteriorated when left at a high temperature for a long time.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, an object of the present invention is to provide a capacitor and a method of manufacturing the same which are less likely to deteriorate at high temperatures despite using a conductive polymer as an electrode.

[0008]

In order to achieve the above object, the present invention provides an electrode having a conductive polymer laminated on a dielectric film, wherein the conductive polymer is COOR.
₁ group, CONH ₂ group, CHO group, COR ₂ group, CF ₃ group, C
A phenol or phenoxide derivative having at least one substituent selected from N groups and SO ₂ NH ₂ groups (where R ₁ represents hydrogen or an alkyl group, and R ₂ represents an alkyl group); Use less supporting electrolyte
The capacitor manufacturing method according to the present invention is formed from an electrolyte solution containing at least a conductive polymer layer by an electrolytic polymerization method from the electrolyte solution having the above-described configuration.

The COOR ₁ group and CONH ₂ used in the present invention
Group, CHO group, COR ₂ group, CF ₃ group, CN group, SO ₂ N
A phenol or phenoxide derivative having at least one substituent selected from among H ₂ groups (where R ₁ is H or an alkyl group, and R ₂ is an alkyl group) has at least a specific substituent selected from the above. It is only necessary to have one, and there is no limitation on the number of each substituent, the position of the substituent, the presence or absence of another substituent, and the type thereof.

Phenol is an aromatic hydroxy compound, which is not limited by the number and position of hydroxyl groups, but also includes monohydric phenol, polyhydric phenol, bisphenol, naphthol, binaphthol, anthrol, anthrahydroquinone and the like. Contains. Phenoxide is a salt of the above-mentioned phenol, and includes ammonium salts in addition to metal salts such as sodium, potassium, calcium, barium, and aluminum.

Phenol or phenoxide derivatives having at least one specific substituent include, specifically, hydroxybenzoic acid, ethyl hydroxybenzoate, hydroxyisophthalic acid, hydroxybenzamide, hydroxybenzaldehyde, vanillin, hydroxyacetophenone, hydroxybenzotrifluoride Lide, hydroxybenzonitrile, hydroxybenzenesulfonamide, dihydroxybenzoic acid, hydroxynaphthoic acid, ethyl sodium hydroxybenzoate, ethyl potassium hydroxybenzoate, sodium trifluoromethoxyresorsilide, sodium hydroxynaphthoic acid, and the like.

The above-mentioned phenol or phenoxide derivative may be used alone or as a mixture of both. Although the concentration of the phenol or phenoxide derivative in the electrolyte is very small, it is effective, but the molar ratio with respect to the polymerizable monomer is preferably 10% or more, and particularly 20% or more, which is particularly effective.

As the polymerizable monomer used in the present invention, pyrrole or a derivative thereof (for example, N-methylpyrrole) is preferably used, but in addition, for example, thiophene, furan or the like may be used.

The supporting electrolyte may be any commonly used one such as perchlorate, sulfonate, carboxylate, phosphate, etc., but naphthalenesulfonic acid having an alkyl substituent may be used. Salts or alkyl phosphates are preferred. More specifically, sodium monomethylnaphthalenesulfonate, sodium triisopropylnaphthalenesulfonate, sodium monoisopropylnaphthalenesulfonate, sodium dibutylnaphthalenesulfonate, propylphosphate,
Butyl phosphate, hexyl phosphate and the like.

The above-mentioned monomers and supporting electrolytes may be used alone, respectively, or a plurality of the above-mentioned polymerizable monomers may be used such as a mixture of plural kinds of supporting electrolytes or a mixture of pyrrole and thiophene with their derivatives. Species may be used in combination. Further, in order to composite the conductive polymer layer, an appropriate additive may be added to the electrolytic solution. Further, the capacitor of the present invention is not limited to the compounds and processing steps exemplified above, and it goes without saying that alternative compounds and processing steps other than those exemplified may be used.

[0016]

According to the capacitor and the method of manufacturing the same of the present invention, it is considered that the conductive polymer layer has a well-structured structure and the number of deterioration starting points such as oxidation starting points is reduced by the above-mentioned structure. The deterioration of various properties that occurs when the conductive polymer is left at a high temperature for a long time is predominantly caused by oxidation caused by the action of oxygen in the air and the conductive polymer. Even when the conductive polymer layer of the capacitor is left at a high temperature for a long time, deterioration of various characteristics is less likely to occur. As a result, even though the capacitor of the present invention uses a conductive polymer as an electrode, it can be a capacitor excellent in stability without deterioration of various characteristics even at a high temperature.

[0017]

Embodiments of the present invention will be described below in detail.

(Embodiment 1) FIG. 1 is a sectional view of a capacitor according to the present invention. 7mm x 10 with anode lead
The dielectric film 2 was formed on the etched foil surface by subjecting the aluminum etched foil 1 having a thickness of 1 mm to anodic oxidation at a temperature of about 70 ° C. and an applied voltage of 70 V for 40 minutes using a 3% ammonium adipate aqueous solution.

Then, after being immersed in a 30% aqueous solution of manganese nitrate and naturally dried, it was heated at 300 ° C. for 30 minutes to perform a thermal decomposition treatment, and a conductive layer of the manganese oxide layer 3 was formed on the dielectric film. Next, the etched foil provided with the conductive layer,
Hydroxybenzoic acid (0.15M), pyrrole (0.5
M), sodium triisopropylnaphthalenesulfonate (0.1 M) and water in an electrolytic polymerization solution, and the electrode for polymerization initiation was brought close to the conductive layer, and a constant voltage of 2.5 V was applied to the electrode for polymerization initiation for 30 minutes. For minutes, an electrolytic polymerization reaction was performed to form an electropolymerized polypyrrole layer 4. After the formation of the electrolytically-polymerized polypyrrole layer, the layer was washed with water and dried, and then a carbon layer 5 and a silver paste layer 6 were sequentially provided on the electrolytically-polymerized polypyrrole layer to obtain a capacitor of the present invention. The number of manufactured is ten.

After the obtained capacitor was aged at 20V for 1 hour, the initial capacity and loss factor (120H
z) was measured. Then, at high temperature (125 ° C), 100
After exposure for 0 hours, the capacity and loss factor (120H
z) was measured. The average of the measured values is shown in (Table 1).

(Comparative Example 1) For comparison, ten capacitors for comparison were prepared under the same conditions as in Example 1 except that hydroxybenzoic acid was not added to the electrolytic polymerization solution, and similar measurements were performed. The average of the measured values is shown in Table 1 as Comparative Example 1. Comparison between the two shows that the capacitor of the present invention has much better stability at high temperatures.

(Example 2) Ten capacitors of the present invention were produced in the same manner as in Example 1 except that hydroxybenzamide was added to the electrolytic polymerization solution instead of hydroxybenzoic acid. After the obtained capacitor was aged at 20 V for 1 hour, the initial capacity and loss factor (120 Hz) were measured. Then, after exposing at a high temperature (125 ° C.) for 1000 hours, the capacity and the loss factor (120 Hz) were measured again. The average of the measured values is shown in (Table 1).

As can be seen from comparison with Comparative Example 1, the capacitor of the present invention has much better stability at high temperatures.

Example 3 A capacitor of the present invention was manufactured in the same manner as in Example 1 except that hydroxybenzaldehyde was added to the electrolytic polymerization solution instead of hydroxybenzoic acid.
This was produced. After aging the obtained capacitor at 20V for 1 hour, the initial capacity and loss factor (120H
z) was measured. Then, at high temperature (125 ° C), 100
After exposure for 0 hours, the capacity and loss factor (120H
z) was measured. The average of the measured values is shown in (Table 1).

Compared with Comparative Example 1, it is clear that the capacitor according to the present invention has much better stability at high temperatures.

Example 4 Ten capacitors of the present invention were produced in the same manner as in Example 1 except that hydroxyacetophenone was added to the electrolytic polymerization solution instead of hydroxybenzoic acid. After aging the obtained capacitor at 20 V for 1 hour, the initial capacity and loss factor (120 Hz)
Was measured. Then, after exposure to high temperature (125 ° C.) for 1000 hours, the capacity and the loss coefficient (120 Hz) are again obtained.
Was measured. The average of the measured values is shown in (Table 1).

As can be seen from comparison with Comparative Example 1, the capacitor according to the present invention has much better stability at high temperatures.

Example 5 Ten capacitors of the present invention were produced in the same manner as in Example 1 except that hydroxybenzotrifluoride was added to the electrolytic polymerization solution instead of hydroxybenzoic acid. After aging the obtained capacitor at 20 V for 1 hour, the initial capacity and loss factor (120
Hz). Then, at high temperature (125 ° C), 10
After exposure for 00 hours, the capacity and loss factor (120
Hz). The average of the measured values is shown in (Table 1).

As is clear from comparison with Comparative Example 1, the capacitor according to the present invention has much better stability at high temperatures.

Example 6 Ten capacitors of the present invention were produced in the same manner as in Example 1 except that hydroxybenzonitrile was added to the electrolytic polymerization solution instead of hydroxybenzoic acid. After aging the obtained capacitor at 20 V for 1 hour, the initial capacity and loss factor (120 Hz)
Was measured. Then, after exposure to high temperature (125 ° C.) for 1000 hours, the capacity and the loss coefficient (120 Hz) are again obtained.
The average of the measured values is shown in Table 1.

As can be seen from comparison with Comparative Example 1, the capacitor according to the present invention has much better stability at high temperatures.

Example 7 Ten capacitors of the present invention were produced in the same manner as in Example 1 except that hydroxybenzenesulfonamide was added to the electrolytic polymerization solution instead of hydroxybenzoic acid. After aging the obtained capacitor at 20 V for 1 hour, the initial capacity and loss factor (12
0 Hz). Then, at high temperature (125 ° C),
After exposure for 2,000 hours, the capacity and loss factor (12
0 Hz). The average of the measured values is shown in (Table 1).

As can be seen from the comparison with Comparative Example 1, the capacitor according to the present invention has much better stability at high temperatures.

Example 8 Ten capacitors of the present invention were produced in the same manner as in Example 1 except that ethyl hydroxybenzoate was added to the electrolytic polymerization solution instead of hydroxybenzoic acid. After aging the obtained capacitor at 20 V for 1 hour, the initial capacity and loss factor (120 Hz)
Was measured. Then, after exposure to high temperature (125 ° C) for 1000 hours, the capacity and the loss coefficient (120Hz) are again obtained
Was measured. The average of the measured values is shown in (Table 1).

As can be seen from comparison with Comparative Example 1, the capacitor according to the present invention has much better stability at high temperatures.

Example 9 Ten capacitors of the present invention were produced in the same manner as in Example 1 except that hydroxynaphthoic acid was added to the electrolytic polymerization solution instead of hydroxybenzoic acid. After the obtained capacitor was aged at 20 V for 1 hour, the initial capacity and loss factor (120 Hz) were measured. Then, after exposing at a high temperature (125 ° C.) for 1000 hours, the capacity and the loss factor (120 Hz) were measured again. The average of the measured values is shown in (Table 1).

As can be seen from comparison with Comparative Example 1, the capacitor according to the present invention has much better stability at high temperatures.

Example 10 Ten capacitors of the present invention were produced in the same manner as in Example 1 except that sodium hydroxybenzoate was added to the electrolytic polymerization solution instead of hydroxybenzoic acid. After aging the obtained capacitor at 20 V for 1 hour, the initial capacity and loss factor (120
Hz). Then, at high temperature (125 ° C), 10
After exposure for 00 hours, the capacity and loss factor (120
Hz). The average of the measured values is shown in (Table 1).

As can be seen from comparison with Comparative Example 1, the capacitor according to the present invention has much better stability at high temperatures.

Example 11 Ten capacitors of the present invention were produced in the same manner as in Example 1 except that n-butyl phosphate was used in place of sodium triisopropylnaphthalenesulfonate. The obtained capacitor is 20
After aging for 1 hour at V, the initial capacity and loss factor (120 Hz) were measured. Then, under high temperature (125
C.) for 1000 hours, and the capacity and the loss factor (120 Hz) were measured again. The average of the measured values is shown in (Table 1).

Comparative Example 2 For comparison, ten capacitors were produced under the same conditions as in Example 11 except that hydroxybenzoic acid was not added to the electrolytic polymerization solution, and similar measurements were performed. The average of the measured values is shown in Table 1 as Comparative Example 2.
Comparison between the two shows that the capacitor according to the present invention has much better stability at high temperatures.

Example 12 In place of the electrolytic solution consisting of pyrrole (0.5M), sodium triisopropylnaphthalenesulfonate (0.1M) and water, thiophene (0.5M), p-toluenesulfur
Ten capacitors of the present invention were produced in the same manner as in Example 8, except that an electrolytic solution composed of tetrabutylammonium phonate (0.1 M) and acetonitrile was used. After aging the obtained capacitor at 20V for 1 hour,
The initial capacity and loss factor (120 Hz) were measured. Then, after exposing at a high temperature (125 ° C.) for 1000 hours, the capacity and the loss factor (120 Hz) were measured again. The average of the measured values is shown in (Table 1).

Comparative Example 3 For the purpose of comparison, Example 12 was repeated except that ethyl hydroxybenzoate was not added to the electrolytic polymerization solution.
Under the same conditions as above, ten capacitors were manufactured and similar measurements were performed. The average of the measured values is shown in Table 1 as Comparative Example 3. Comparing the two, the capacitor according to the present invention is
It can be clearly seen that the stability at high temperatures is much better.

[0044]

[Table 1]

In the examples, only the case where thiophene was used in addition to pyrrole as the polymerizable monomer was described. However, if the conductive polymer has an electric conductivity that can be used as an electrode, other polymerizable monomers may be used. can do.

Further, in the embodiment, only the case where a sodium salt is used as a supporting electrolyte has been described, but a potassium salt, an ammonium salt and the like can also be used as a supporting electrolyte.

In the embodiment, only a solid electrolytic capacitor using aluminum as a valve metal as an anode has been described. However, as is clear from the gist of the present invention, the capacitor has an electric conductivity that can be used not only as a valve metal but also as an electrode. Any substance can be used.

Furthermore, in the embodiments, only the case where aluminum oxide is used as the dielectric has been described. However, the effect of the present invention can be hindered by using a material such as electrodeposited polyimide which can be used as a dielectric for other capacitors. Not something.

In the embodiment, only the capacitor having polarity has been described. However, as is clear from the gist of the present invention, the same effect can be obtained with a non-polar capacitor.

In the embodiment, only the case where a conductive polymer is used for one electrode has been described. However, it is also possible to use a conductive polymer for another electrode. It is not limited by the number of electrodes using.

In the embodiment, only the case where a manganese oxide which is a base material for electrolytic polymerization is formed on an aluminum oxide which is a dielectric film, and then a conductive polymer is laminated by electrolytic polymerization has been described. The effect of the present invention is not limited by the type of the base material for electrolytic polymerization and whether or not the base material for electrolytic polymerization is used.

[0052]

As described above, according to the capacitor of the present invention and the method of manufacturing the same, _one COOR group, one CONH ₂ group,
At least one substituent selected from a CHO group, a COR ₂ group, a CF ₃ group, a CN group, an SO ₂ NH ₂ group (where R ₁ represents H or an alkyl group, and R ₂ represents an alkyl group) By forming a conductive polymer obtained by electrolytic polymerization from an electrolytic solution containing at least a phenol or phenoxide derivative having a polymerizable monomer and a supporting electrolyte on a dielectric film and using it as an electrode, high conductivity is obtained. Despite the use of molecules as electrodes, a capacitor having excellent stability even at high temperatures can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a capacitor according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Aluminum-etched foil 2 Dielectric film 3 Manganese oxide layer 4 Electropolymerized polypyrrole 5 Carbon layer 6 Silver paste layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H01G 1/01 (72) Inventor Masao Fukuyama 3-10-1, Higashi-Mita, Tama-ku, Kawasaki-shi, Kanagawa Prefecture Matsushita Giken Co., Ltd. (56 References JP-A-4-184811 (JP, A) JP-A-64-49212 (JP, A) JP-A-2-119212 (JP, A) JP-A-2-130906 (JP, A) (58) Surveyed fields (Int.Cl. ⁶ , DB name) H01G 9/028 H01G 4/18 301

Claims (5)

(57) [Claims] An electrode having a conductive polymer laminated on a dielectric film, wherein the conductive polymer is COO
R ₁ group, CONH ₂ group, CHO group, COR ₂ group, CF ₃ group,
A phenol or phenoxide derivative having at least one substituent selected from a CN group and an SO ₂ NH ₂ group (R ₁ represents hydrogen or an alkyl group, R ₂ represents an alkyl group); and a supporting electrolyte small
A capacitor characterized by being formed from at least a contained electrolytic solution . 2. The method according to claim 1, wherein at least one hydrogen of the alkyl group is
2. The capacitor according to claim 1, wherein said capacitor is an alkyl group substituted by halogen. 3. The capacitor according to claim 1, wherein the polymerizable monomer is pyrrole or a derivative thereof. 4. The capacitor according to claim 1, wherein the supporting electrolyte is a naphthalene sulfonate or an alkyl phosphate having an alkyl substituent. 5. The method according to claim 1, wherein the conductive polymer layer is formed by electrolytic polymerization.