JPH0241887B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a solid capacitor using a complex salt of 7,7,8,8 tetracyanoquinodimethane (TCNQ) as an electrolyte. [Prior Art] Conventionally, in solid electrolytic capacitors, an oxide film such as aluminum oxide is formed on a film-forming metal such as aluminum to form an anode side electrode, and a solid electrolyte is further adhered to the surface thereof.
In a solid electrolytic capacitor, the solid electrolyte is an important element in determining its electrical characteristics. Manganese dioxide has been used in conventional solid electrolytes, but when this manganese dioxide is used,
In addition to the disadvantage that the oxide film of the film-forming metal is easily damaged by the heat applied when forming the electrolyte layer, there are also disadvantages such as poor repairability of the oxide film. Therefore, it was proposed to use TCNQ salt, an organic conductor, as a solid electrolyte instead of manganese dioxide. This is because the time it takes for TCNQ salt to melt and decompose by heating has enough time to complete the adhesion work as an electrolyte, so if it is cooled and solidified within that work time, it will have high conductivity. It is based on the property of obtaining a solid electrolyte. However, conventionally used TCNQ salts are made from isopropylquinoline and N-methyl-quinoline, which are said to have relatively high thermal stability.
Even TCNQ salts show stability only up to about 150°C. Therefore, if the temperature of the salt bath during deposition of the TCNQ salt exceeds 200° C., the TCNQ salt will thermally decompose and most of it will become an electrical insulator. For this purpose, dissolve TCNQ salt in a given solvent,
This solution is applied to the film-forming metal and allowed to dry.
A method has been proposed in which the film-forming metal is impregnated with only the TCNQ salt by scattering a solvent, but according to such a method, it is difficult to fully impregnate the film-forming metal with the solid electrolyte. , it requires a process of repeating coating and drying many times, and there are disadvantages such as low work efficiency. [Problems to be Solved by the Invention] The present invention solves the conventional drawbacks and provides a solid capacitor using an electrolyte that exhibits sufficient thermal stability even in a relatively high temperature range and has high conductivity. This is what I am trying to do. [Means for Solving the Problems] In the present invention, an electrolyte is a conductive substance formed by combining metallocenes and 7,7,8,8 tetracyanoquinodimethane. [Function] By using such a conductive complex, an electrolyte that exhibits sufficient thermal stability even in a high temperature range and has high conductivity can be obtained. [Embodiments] The present invention will be described in detail below with reference to embodiments shown in the drawings. To explain the manufacturing method of the solid capacitor of this invention, as shown in Figure 1, metallocenes and
A conductive substance formed by combining TCNQ, that is, a TCNQ complex salt, is used as an electrolyte. For example, combining metallocenes or metallocene dielectrics (including ionic types) with TCNQ, or
Ferrocene or ferrocene derivatives (including ionic forms) are combined with TCNQ to form a conductive material. In this case, ferrocene is one of metallocenes, and metallocenes constitute metallocenes including derivatives of metallocenes, and function as cations in complex salts. That is, the conductive substance is
Consists of TCNQ complex salt. Then, as shown in FIG. 1, in the container 2, for example, TCNQ salt of ferrocene (hereinafter referred to as
(referred to as TCNQ salt) 4 is heated and dissolved at a temperature of about 265° C., and the capacitor element 6 is immersed in the dissolved TCNQ salt 4 to adhere the TCNQ salt 4 to the electrode surface. The capacitor element 6 has a cylindrical shape, which is obtained by subjecting a foil made of a film-forming metal such as aluminum to a chemical conversion treatment, forming a dielectric oxide film on its surface, and then winding the foil. Then, the capacitor element 6 was pulled up after the salt bath of TCNQ salt 4, and the capacitor element 6 was removed from the electrode surface.
Cool and solidify TCNQ salt 4. Through this cooling and solidification, the TCNQ salt 4 becomes a solid electrolyte. The thus obtained capacitor element 6 has a graphite layer 10 and a silver paint layer 12 formed on its surface, and is housed in an exterior case 14 and fixed with solder 16 and synthetic resin 18. An anode-side lead 20 is electrically connected to the anode-side electrode of the capacitor element 6, and a cathode-side lead 22 is electrically connected to the cathode-side solder 16 and drawn out to the outside. The thus obtained solid capacitors include one in which the solid electrolyte is ferricinium-TCNQ, which is a TCNQ salt of ferrocene, and one in which the solid electrolyte is isopropylquinoline-TCNQ, which is a conventional TCNQ salt of N-n-propylquinoline. Compare the results of life tests conducted at high temperatures with Table 1 shows the high temperature load test (rated 6.3V, 95℃)
Show the results. As is clear from this table, in the case of the solid capacitor according to the present invention, various electrical characteristics such as capacitance, tanδ, and leakage current are almost the same between the initial characteristics and the characteristics after 1000 hours, whereas the conventional In the case of solid electrolytic capacitors, the change in tan δ is particularly large, indicating that there is a large variation in dielectric loss.

〔Effect of the invention〕

As explained above, according to the present invention, a conductive complex consisting of metallocenes such as ferrocene and TCNQ is used as a solid electrolyte, so that it can be used even in a temperature range exceeding 200°C. , electrical properties, e.g.
In addition to being able to provide a heat-resistant solid capacitor with extremely small changes in tanδ, this solid capacitor has a simpler manufacturing process and improved work efficiency compared to the conventional manufacturing method in which a solid electrolyte is attached using a solvent. There are advantages that can be improved.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the salt bath of TCNQ salt, Figure 2
The figure is a longitudinal sectional view showing an example of the solid capacitor of the present invention, and FIG. 3 is a graph showing the thermal stability of each TCNQ salt. 4...TCNQ salt, 6...Capacitor element.

Claims (1)

[Scope of Claims] 1. A solid capacitor characterized in that an electrolyte is a conductive substance formed by combining metallocenes and 7,7,8,8 tetracyanoquinodimethane. 2. The solid capacitor according to claim 1, wherein the metallocene is a metallocene or a metallocene derivative. 3. The solid capacitor according to claim 2, wherein the metallocene is ferrocene or a ferrocene derivative.