JPS61129808A - 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 Field of the Invention The present invention relates to an electrolytic capacitor with an improved solid electrolyte.

Conventional technology A solid electrolytic capacitor in which a solid electrolyte is interposed between an anode electrode made of a valve metal having an anodic oxide film on its surface and a cathode electrode configured to face the electrode includes:
Traditionally, manganese dioxide has been used as the solid electrolyte.

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 thermally decomposed, which causes damage to the anodic oxide film, and in addition, the anodic oxidation with manganese dioxide There was a problem that the repairability of the film was poor.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a structure between an anode electrode made of a valve metal having an anodic oxide film on its surface and a cathode electrode arranged opposite to the anode electrode. Benzothiazole-N-radicals as intervening electrolytes and 7.7.8.
This is a solid electrolytic capacitor characterized by using an organic semiconductor compound consisting of 8-tetracyanoquinodimethane.

Characteristics as a working donor material include a suitably small ionization potential, a stable π-electron system with a large resonance structure, and a high polarizability. Satisfying all of these conditions is an important factor in the molecular design of the donor material, and in order to apply the complex to electrolytic capacitors, there is a problem with adhesion to the electrodes, so it is necessary to use complexes with extremely fine crystal grains. 7.7.8.8 tetracyanoquinodimethane (hereinafter referred to as TCNQ), which has good compatibility with metal oxides, is desirable.

Furthermore, a TCNQ complex is required that does not change its electrical conductivity much from low to high temperatures and is difficult to decompose even at high temperatures.

Therefore, the inventor of the present invention repeatedly conducted various studies and found a TCNQ donor material that satisfies the above requirements as much as possible.

Benzothiazole-N-radicals have a considerably small tensile as shown below, and a very large polarizability due to the large bias of electrons due to the radical.

Regarding the expansion of the π-electron system, the N and S atoms have independent electron pairs, which stabilize the resonance with the 6 π-electrons of the benzene ring, resulting in a wide π-electron expansion. Therefore, although it is a radical, it is not very reactive, and when giving electrons to TCNQ, which is an acceptor material, it has a molecular structure that is most stable when it is kept in an intermediate state without giving away electrons completely. It has very good electrical conductivity, and the conductivity of the pellet compressed at 400 kg/crA at room temperature was 3Ω-'Cl11-'.

Example Specific examples of the present invention will be described below.

Ammonium phosphate is an aluminum foil etched with a surface magnification of about 10 times as an electrode. Yong? 80V using night
Chemical conversion was performed and sufficient drying was performed. Next benzo 1.3.2
Dithiazole 2yl (TCNQ) z complex was heated and dissolved in acetonitrile to create a saturated solution, which was applied onto the electrode and heated at 80 to 90°C to scatter off the solvent acetonitrile. This operation was repeated three times, colloidal carbon was applied and dried as a cathode, and then silver paste was applied and lead wires were soldered and packaged to prepare a capacitor sample (sample group A).

For comparison, as a conventional example, a saturated solution was prepared by dissolving manganese nitrate in water, and the above electrode was immersed in the solution for 50 minutes at 400℃.
A drying process was performed for a minute, and this operation was repeated three times. The cathode and lead wires were attached as described above, and a capacitor sample (sample group B) was prepared in the same manner. The rating for each was 50WV-2, 2μF.

Tables 1 and 2 show the initial characteristics of these two types of capacitors and the reliability (high temperature load test) data in which a rated voltage was applied for 2000 hours in an atmosphere of 105°C.

The capacitance and tan δ are the values at room temperature of 120 Hz, and the leakage current is the value at room temperature and 1 minute after application of the rated voltage.

Table 1 (Initial characteristics) Table 2 (High temperature load test characteristics) Effects of the invention As described above, the solid electrolyte made of the benzothiazole-TCNQ complex quickly bonded to the electrode without damaging the oxide film, and was used as a capacitor. It exhibits excellent characteristics and extremely good reliability, significantly improves and stabilizes the characteristics of solid electrolytic capacitors, and is of great industrial and practical value.

Claims (1)

[Claims] Benzothiazole-N-radicals and 7,7,8, A solid electrolytic capacitor characterized by using an organic semiconductor compound consisting of 8-tetracyanoquinodimethane.