Capacitor electrolyte production

What is an electrolytic capacitor?

An electrolytic capacitor is a polarized capacitor whose anode or positive plate is made of a metal that forms an insulating oxide layer through anodization. This oxide layer acts as the dielectric of the capacitor. A solid, liquid, or gel electrolyte covers the surface of this oxide layer, serving as the cathode or negative plate of the capacitor.

How do electrolytic capacitors work?

Electrolytic capacitors use a chemical feature of some special metals, previously called "valve metals", which on contact with a particular electrolyte form a very thin insulating oxide layer on their surface by anodic oxidation which can function as a dielectric. There are three different anode metals in use for electrolytic capacitors:

How are electrolytic capacitors made?

The dielectric material of electrolytic capacitors is produced from the anode metal itself in what is known as the forming (or anodizing process.

Why do electrolytic capacitors have a high capacitance?

Because of their very thin dielectric oxide layer and enlarged anode surface, electrolytic capacitors have a much higher capacitance - voltage (CV) product per unit volume than ceramic capacitors or film capacitors, and so can have large capacitance values.

How conductive polymer is used in electrolytic capacitors?

Solid electrolyte – conductive polymer is applied in thin layer on anode, cathode and paper foil in order to improve ESR and conductivity. The structure is then dipped into a liquid electrolyte as in the case of standard wet electrolytic capacitors. See Figure C3-7a. Figure 8. Schematic of hybrid Al electrolytic capacitors

Why are electrolytes used in capacitors?

Electrolytes have lower conductivity than metals, so are only used in capacitors when metallic plate is not practical, such as when the dielectric surface is fragile or rough in shape or when ionic current is required to maintain the dielectric integrity.