Wet capacitor cathode containing an alkyl-substituted poly(3,4-ethylenedioxythiophene)

摘要

A wet electrolytic capacitor that contains an anodically oxidized porous anode body, a cathode containing a metal substrate coated with a conductive coating, and a working electrolyte that wets the dielectric on the anode. The conductive coating contains an alkyl-substituted poly(3,4-ethylenedioxythiophene) having a certain structure. Such polymers can result in a higher degree of capacitance than many conventional types of coating materials. Further, because the polymers are generally semi-crystalline or amorphous, they can dissipate and/or absorb the heat associated with the high voltage. The degree of surface contact between the conductive coating and the surface of the metal substrate may also be enhanced in the present invention by selectively controlling the manner in which the conductive coating is formed.

主权项

1. A wet electrolytic capacitor comprising:
an anode comprising a sintered porous anode body that is coated with a dielectric, wherein the anode body comprises tantalum; a cathode that comprises a metal substrate over which is disposed a conductive polymer coating, wherein the conductive polymer coating contains an alkyl-substituted poly(3,4-ethylenedioxythiophene) having the following general structure:wherein R2 is hydrogen or an alkyl group, n is from 1 to 2,000, and y is from 1 to 10; and
a fluid working electrolyte in communication with the anode and the cathode, wherein the electrolyte has a pH of from about 4.5 to about 7.0.