JPH0777183B2 - New solid electrolytic capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a solid electrolytic capacitor using a solid electrolyte.

[Prior Art] A solid electrolytic capacitor has a structure in which a solid electrolyte is attached to a dielectric film-forming metal such as aluminum having an anodized film. Until now, manganese dioxide has mostly been used as a solid electrolyte in this type of capacitor.

[Problems to be Solved by the Invention] However, when manganese dioxide is formed on an electrode, it is generally immersed in a manganese nitrate solution and then hydrolyzed. However, there is a defect that the repairability of the anodized film by manganese dioxide is poor.

For the purpose of improving the above-mentioned drawbacks, it has been proposed to use an organic semiconductor, mainly a salt of 7,7,8,8-tetracyanoquinodimethane (TCNQ) (TCNQ complex) as a solid electrolyte.

The TCNQ complex uses TCNQ as an acceptor material, and quinoline (Qn), tetrathiafulvalene (TTF), N as a donor material.
-Methylphenazine (NMP), tetraselenafulvalene (TSF), etc. have been studied so far, and research on more fun donor materials has been energetically conducted, but satisfactory results have not yet been obtained. .

In particular, in terms of heat resistance, all TCNQ complexes that have been studied so far have problems. In other words, solid electrolytic capacitors are often exposed to heat such as soldering in the manufacturing process of capacitors, and are placed near the transformer in the power supply circuit. ,
The electrolyte must be thermally stable, but traditional TCNQ
All of the complexes have anxiety in this respect. That is, for example, various solid electrolytic capacitors using a TCNQ complex using isoquinoline as a donor material as a solid electrolyte have been proposed so far, but none of them has solved the above problems.

[Object of the Invention] An object of the present invention is to provide a new and useful solid electrolytic capacitor which does not have the above-mentioned problems of the solid electrolytic capacitor.

[Summary of the Invention] The present invention provides an electrolyte as an electrolyte to be interposed between an electrode for an anode made of a valve metal having an anodized film on the surface and an electrode for a cathode that is formed to face the electrode. [Wherein R ¹ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms,
Represents an alkoxy group having 1 to 4 carbon atoms, a cyano group, a nitro group, a trifluoromethyl group, a fluoro group or a hydroxyl group, R
² is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or-(CH ₂ ).
_n -OCH ₃ (where, n denotes. any integer of 1 to 5) shows a. ] The 1-substituted-4- [2-phenyl (or substituted phenyl) ethenyl] pyridinium cation represented by these is used as a donor material, and a TCNQ complex is used, It is a solid electrolytic capacitor characterized by the above-mentioned.

That is, the present inventors have conducted extensive studies to achieve the above object, and (In the formula, R ¹ and R ² are the same as above.) The TCNQ complex having a 1-substituted-4- [2-phenyl (or substituted phenyl) ethenyl] pyridinium cation as a donor material has heat resistance, It has excellent stability, and when it is applied to the solid electrolyte of an electrolytic capacitor, it shows excellent temperature characteristics and stability, especially when it is soldered to a printed circuit board after being commercialized The inventors have found that reflow is possible and have completed the present invention.

The TCNQ complex used in the present invention is represented, for example, as follows.

(In the formula, k represents an arbitrary number of 0.5 ≦ k ≦ 2.0.) In the TCNQ complex according to the present invention, the formula of the donor part R ¹ of the 1-substituted-4- [2-phenyl (or substituted phenyl) ethenyl] pyridinium cation represented by is a hydrogen atom, for example, a methyl group, an ethyl group, a propyl group, a butyl group or the like having 1 to 4 carbon atoms. A linear or branched alkyl group, for example, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, etc., a linear or branched alkoxy group having 1 to 4 carbon atoms, a cyano group, a nitro group, a fluoro group, Represents a trifluoromethyl group or a hydroxyl group, and R ² represents a hydrogen atom, for example, a methyl group, an ethyl group, a propyl group, a butyl group, an amyl group, a hexyl group, a heptyl group, an octyl group, and the like.
8 is a linear or branched alkyl group, or is, for example, a methoxymethyl group, a methoxyethyl group, a methoxypropyl group, a methoxybutyl group, a methoxyamyl group, or the like, of the formula — (CH ₂ ) _n —OCH ₃ (however, , N represents an arbitrary integer of 1 to 5).

The TCNQ complex according to the present invention can be produced by a method known per se, for example, 1-
Reacting a halide of a substituted-4- [2-phenyl (or substituted phenyl) ethenyl] pyridinium cation with a Li salt of TCNQ, And can be easily synthesized by a method of doping it with neutral TCNQ. The halide of the 1-substituted-4- [2-phenyl (or substituted phenyl) ethenyl] pyridinium cation is, for example, the compound X—R ² (wherein, X represents a halogen atom, and R ² is the same as the above). If necessary, it can be easily obtained by reacting with 4- (2-phenylethenyl) pyridine or 4- (2-substituted phenylethenyl) pyridine in the presence of a suitable solvent. It is enough to use the obtained one. Also, X-R ²
Among the compounds represented by, methoxyalkyl halide is
For example, since it can be easily synthesized from an alkyl chloride and a metal methylate according to the method described in J. Am. Chem. Soc., 72 , 1334 (1950), it is sufficient to use the thus obtained product. Further, 4- (2-phenylethenyl) pyridine or 4- (2-substituted phenylethenyl) pyridine, for example, J.Org.Chem., 28, 387 ( 1963), J.Org.Chem., 21 , 1
039 (1956), J.Chem.Soc., 1960 , 1516, J.Chem, Soc., 19
Since it can be easily obtained by reacting γ-picoline with benzaldehyde or a substituted benzaldehyde in acetic anhydride according to the method described in 34,276, etc., it is sufficient to use the thus obtained product. In addition, according to the present invention
TCNQ complexes, iodine ion I ^- using the reducing power, 1
Iodide of -substituted-4 [2-phenyl (or substituted phenyl) ethenyl] pyridinium cation Needless to say, it can be similarly synthesized by a method of reacting with neutral TCNQ at a molar ratio of 3: 4.

Since the TCNQ complex according to the present invention is stable up to high temperature, it brings an advantageous advantage in the bonding technique with the electrode. That is,
It can be dissolved in a solvent with a high boiling point and high polarity, and recrystallization on the electrode surface occurs very quickly during immersion and drying. Further, it is reasonably impregnated into the unevenness of the electrode that is finely etched like an aluminum electrolytic capacitor. Although this has a problem in that the conditions such as the crystallization rate are not taken into consideration, it goes without saying that the impregnation state becomes better as the crystal becomes finer and the density becomes higher.

Incidentally, the anode electrode used in the solid electrolytic capacitor of the present invention is not limited to the aluminum foil, and other valve action metals can be used as a matter of course. It goes without saying that the effect can be obtained.

Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto.

Examples Reference Example 1. Table 1 shows the basic physical properties of several typical TCNQ complexes used in the present invention.

Example 1. (Preparation of Sample Group-I) Among the compounds exemplified in Reference Example 1, complexes A to F were tested using aluminum electrolytic capacitor elements rated at 10 WV-33 μF. For the impregnation, each complex was supersaturated in a nitrobenzene solution heated to 180 ° C., the device was dipped and dried at 210 ° C. This operation was repeated 4 times to complete the impregnation to obtain a product.

(Preparation of Sample-II) Using Nn-butylisoquinoline TCNQ complex, impregnation and commercialization were performed according to the preparation method of Sample group-I.

(Preparation of Sample-III) Using a saturated aqueous solution of manganese nitrate, dipping at 220 ° C. for 60 seconds,
After repeating the heat treatment 6 times, the sample was commercialized in the same manner as Sample Group-I.

(Results) Initial characteristics are shown in Table-2. Capacitance and tanδ are 1 at room temperature
The value at 20Hz and the leakage current are the values at room temperature and 1 minute after the rated voltage was applied.

Furthermore, Table 3 (1) to (3) shows the results of high-temperature load tests for up to 2000 hours with a rated voltage applied in an atmosphere of 105 ° C.

From the results of Table-2 and Table-3 (1) to (3), it was proved that the electrolytic capacitor using the TCNQ complex according to the present invention is considerably stable thermally.

Example 2. (Preparation of sample group-IV) Using complexes G to K shown in reference example 1, sample group-IV was prepared according to the method for preparing sample group-I of example 1.

(Results) Table 4 shows the results of investigating the characteristic changes due to reflow by performing reflow at 230 ° C for 60 seconds using Sample Group-IV and Samples II and III.

As is clear from the results in Table 4, the capacitance of the product using Nn-butylisoquinoline TCNQ complex and the product using manganese dioxide are significantly increased, and due to the thermal stress during reflow, Although it is shown that the complex is deteriorated, it can be seen that the solid electrolytic capacitors using the complex according to the present invention all have stable capacitance, tan δ and leakage current and are extremely stable products.

[Effects of the Invention] As described above, the TCNQ complex used in the present invention is extremely stable thermally as a solid electrolyte, and the bondability between the electrode and the solid electrolyte is good. The solid electrolytic capacitor of (1) has a remarkable effect in that its electric characteristics are remarkably improved and stabilized as compared with the conventional one, and is of industrial and practical value.

Claims (1)

[Claims] 1. An electrolyte to be interposed between an electrode for an anode made of a valve metal having an anodized film on the surface and an electrode for a cathode arranged so as to face the electrode. [Wherein R ¹ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms,
Represents an alkoxy group having 1 to 4 carbon atoms, a cyano group, a nitro group, a trifluoromethyl group, a fluoro group or a hydroxyl group, R
² is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or-(CH ₂ ).
_n -OCH ₃ (where, n denotes. any integer of 1 to 5) shows a. ] The solid electrolytic capacitor characterized by using the TCNQ complex which used the 1-substituted-4- [2-phenyl (or substituted phenyl) ethenyl] pyridinium cation represented by these as a donor material.