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.
The positive electrode is connected to the metal substrate with an oxide film, while the negative electrode is connected to the electrolyte through a metal electrode plate. Non-polar electrolytic capacitors, also known as bipolar electrolytic capacitors, have a dual oxide film structure.
Electrolytic capacitors are more complicated than electrostatic capacitors in their construction. The function of electrolyte is to provide electric connection to the first electrode with very high surface with fine structure and thus to achieve high capacitance values.
The second type does not use a single carbon electrode but instead metal oxides for both the positive and negative electrodes. For example, an hybrid capacitor based on Fe 3 O 4 and MnO 2 have been investigated with an aqueous electrolyte [16.17]. The third and fourth types are based on intercalation compounds as active electrode materials.
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
Interf. 17, 53 (2008) D. Bélanger: Polythiophenes as active electrode materials for electrochemical capacitors. In: Handbook of Thiophene-Based Materials, ed. by I.F. Perepichka, D. Perepichka (Wiley, New York 2009) pp. 577–594 T. Brousse, D. Bélanger: A hybrid Fe 3 O 4 MnO 2 capacitor in mild aqueous electrolyte, Electrochem.
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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. Because of their very thin dielectric oxide layer and enlarged an…