Composite electrode and electrolytic capacitor

Abstract

Provided is a composite electrode including a metal layer and a composite dielectric layer. The composite dielectric layer includes a metal oxide dielectric layer and a polymer dielectric layer. The composite dielectric layer overlays the metal layer. The polymer dielectric layer includes a nitrogen-containing polymer and overlays the metal oxide dielectric layer. An electrolytic capacitor is also provided. The electrolytic capacitor has a polymer dielectric layer made of a nitrogen-containing polymer, and such polymer dielectric layer is beneficial to increase the insulating property of the metal oxide dielectric layer and the coverage property of the conductive polymer. Thereby, the conventional leakage current can be significantly reduced and the yield can be improved.

Description

technical field [0001] The invention relates to a composite electrode and an electrolytic capacitor. Background technique [0002] For a long time, improving the conductivity of the electrolyte and increasing the pass rate of the capacitor have been the main issues in the development of electrolytic capacitors. The electrolyte with high conductivity can reduce the equivalent series resistance of the capacitor, achieve high frequency low impedance and have high reliability characteristics. Since conductive polymers have higher conductivity than liquid electrolytes or solid organic semiconductor complex salts (such as tetracyanodimethylbenzoquinone (TCNQ) compound salts) used in traditional electrolytic capacitors, and have high-temperature insulation properties, There is no risk of capacitor explosion caused by liquid volatilization in liquid capacitors, so conductive polymers have become the development trend of solid electrolytes used in electrolytic capacitors today. [...

AI Technical Summary

Problems solved by technology

However, the reliability of conductive polymer high-voltage capacitors cannot be improved due to some factors

First, when the oxide layer is anodized aluminum oxide, the aluminum oxide layer is inhomogenous, and its grain boundaries are likely to cause cracks, resulting in increased leakage current

Second, due to the poor properties of the conductive polymer film layer and its brittleness, long-term use is likely to deform itself due to vibration from the environment, or cause oxide layer damage (breakdown)

Third, the film-forming properties of conductive polymers are poor and cannot completely cover the surface of the oxide layer of the capacitor, resulting in high leakage, high impedance and low pass rate of the capacitor

The above factors often lead to low capacitance, a sharp rise in leakage current or even a short circuit, resulting in a decline in the pass rate of high-voltage capacitors

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