JPS63215034A - Solid electrolytic capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a 7,7°8.8-
The present invention relates to a solid electrolytic capacitor using an ionic radical salt of tetracyanoquinodimethane as a solid electrolyte.

[Conventional technology and good luck points] 7.7,8.8-tetracyanoquinodimethane (hereinafter referred to as T
It is abbreviated as CNQ. ) as a solid electrolyte, for example, TCNQ#I salt (Japanese Unexamined Patent Publication No. 191414/1982), which has quinoline or isoquinoline as a cation and TCNQ as an anion, is melted by heating and solidified by cooling. Solid electrolytes are well known. In addition, in the cation of these TCNQ complex salts, the N-position is substituted with an alkyl group selected from among those having 2 to 18 carbon atoms.

The method of heating and melting the TCNQ complex salt and solidifying it by cooling is preferred because it allows the etched aluminum foil or tantalum sintered body to be impregnated with the TCNQ* salt in a molten state. However, on the other hand, TC
If the melting temperature of the NQ complex salt is high or the melting time is long, the TCNQ complex salt, which is an organic semiconductor, will decompose and transform into an insulator. Further, the TCNQ complex salt crystallizes during cooling and solidification, and it has the disadvantage that sufficient contact with the porous portion of the electrode foil cannot be obtained.

[Object of the Invention] However, the present invention is capable of eliminating the above-mentioned drawbacks. Specifically, the present invention is capable of eliminating the above-mentioned drawbacks. Specifically, the guardine conductor TCNQil salt, which has a small specific resistance value and is thermally stable, is made into a solid material. It is an electrolyte. This provides a high-performance and highly reliable solid electrolytic capacitor. T
It has a solid electrolyte made of N Q complex salt.

As mentioned above, the TCNQ salt is the guanidine derivative TCNQ 36 salt;
-9iSO-) or benzyl group. Here, the structural formula of the guanidine derivative TCNQ complex salt is as follows.

Structural formula of guanidine derivative TCNQ complex salt [in 11, R
"c+" represents an alkyl group or benzyl group of c+a, m is a positive number (0
, 5 to 1.5). R1, R2) R3 and Ra represent an alkyl group of H1C1 to C6 or a phenyl group.

When the guanidine derivative is, for example, 1,1,3,3-tetramethylguanidine, R1°R2) Fti, R
4 is a methyl group, and in the case of 1,3-diphenylguanidine, R and R3 are phenyl groups.

Next, l is a representative example of a guanidine derivative.

1.3. The method for synthesizing 3-tetramethylguanidine TCNQtlt salt will be described. 0.01 moles of 1.1.3
．． When 3-tetramethylguanidine and 0.015 mol of methyl iodide are heated in a flask to about 40 to 45 ['C] in a water bath and stirred, a quaternization reaction occurs. A yellow powder (N-methyl iodide-1゜1.3.3-tetramethylguanidine) obtained by cooling this solution
．． 01 mol was dissolved in acetonitrile under boiling conditions to give 0.01 mol.
The mixture is mixed with an acetonitrile solution at 80[° C.] in which 0.2 mol of TCNQ complex salt is dissolved. Thereafter, by cooling at room temperature for about 5 hours, needle-like crystals of N-methyl-1,1,3,3-tetramethylguanidine TCNQ complex salt are obtained.

The crystals are washed with a small amount of acetonitrile, further washed with ethanol until the washing solution is no longer colored, washed with a needle, dried, and applied to a solid electrolytic capacitor.

In addition, in this synthesis step, instead of methyl iodide,
If ethyl iodide, propyl iodide... are used, N-ethyl-1,1゜3.3-tetramethylguanidine TCNQ complex salt, Nn-propyl-1,1,3,3
-Tetramethylguanidine complex salt... is obtained.

In addition, the above-mentioned 1. In addition to the 1,3,3-tetramethylguanidine TCNQ complex salt, 1,3-diphenylguanidine or other guanidine TCNQ complex salts can also be synthesized in the same manner as described above. Table 1 shows the specific resistance values of the guanidine derivative TCNQ complex salt.

[Example] Next, the guanidine derivative TCNQ obtained as described above
An example in which a complex salt is applied to an electrolytic capacitor will be described.

N-methyl-1,1,3,3-tetramethylguanidine TCNQ complex salt was dissolved in acetonitrile and the saturated Ki
Let it be M. Next, the capacitor element was immersed in this solution, and then vacuum-dried at 50 to 60['C] to scatter the solvent acetonitrile. Repeat this operation three times. The capacitor element uses an aluminum foil whose surface is etched approximately 10 times as much as an electrode, and further has an oxide film formed by chemical conversion treatment on the surface. After impregnating with electrolyte, apply colloidal carbon, then apply silver paste, solder the lead wires, and package it.
], a solid electrolytic capacitor with a loss of 3.6% (Example 1
) was obtained. Also, N-methyl-1,3-diphenyl T
When using CN Q Sl salt, constant +%2.2 [
2.4 [μF] for the anode of 3.8 [μF]
% solid electrolytic capacitor (Example 2) was obtained.

Examples of solid electrolytic capacitors according to the present invention obtained as described above (rating: 25 [V] - 2.2 [uF]) and capacitor elements similar to those in the examples were injected with N by thermal melting.
-n-propyl-quinoline T CN Q 31) Table 2 shows a comparison of the life characteristics of the solid electrolytic capacitor obtained by impregnating the salt with Conventional Example 1. In Table 1, the capacitance value and the tangent of the loss angle are values at a frequency of 120 [Hz], and the equal series resistance values are values at a frequency of 100 [KHz]. The leakage current is a value measured 1 minute after application of the rated voltage (25 [V]).

Table 2 Life characteristics Next, other embodiments of the present invention will be described.

A compound 4o [mg] of N-n-butyl-1,1,3,3-tetramethylguanidine TCNQ* salt and a lactone compound, such as γ-butyrolactone, was added to a diameter of 5.0 [mg].
Filled in an aluminum case of 200 ['e]
The mixture was heated for about 10 seconds until it was dissolved. A wound capacitor element in which an anode foil and a cathode foil made of aluminum foil were wound with a separator interposed therein was immersed, and cooled approximately 12 seconds after immersion. Note that, prior to impregnation with the electrolyte, the temperature of the capacitor element was raised to 200['C]. As a result, 2.4 [μF] for an anode with a rating of 2.2 [μF]
”, solid electrolytic capacitor with I loss of 3.7% (Example 3
) was obtained. In addition, when N-methyl-1,3-diphenylguanidine TCNQ complex salt is used, the rating is 2,2[
2.3 [μF], loss 3.9 [%] for the anode of [μF]
] A solid electrolytic capacitor (Example 4) was obtained.

[Effects] The guanidine derivative TCNQ according to the present invention described above
Fusio has higher thermal stability than the conventional quinoline TCNQ complex salt, and can provide an organic semiconductor with a lower specific resistance value. Furthermore, this guanidine derivative TCNQ
When complex salts are used as electrolytes in solid electrolytic capacitors,
As can be seen from Table 1, it is possible to provide a solid electrolytic capacitor with better life characteristics than the conventional example.

Claims (4)

[Claims] (1) A solid electrolytic capacitor characterized in that a guanidine derivative/7,7,8,8-tetracyanoquinodimethane complex salt in which the N-position is substituted with a hydrocarbon group is used as an electrolyte. (2) A solid electrolytic capacitor according to claim (1), characterized in that the N-position of the guanidine derivative is substituted with an alkyl group or benzyl group having 1 to 18 carbon atoms. (3) A solid electrolytic capacitor according to claim (1), characterized in that the guanidine derivative is 1,1,3,3-tetramethylguanidine. (4) The solid electrolytic capacitor according to claim (1), wherein the guanidine derivative is 1,3-diphenylguanidine.