Electrodes for electrolytic capacitors and method for producing them
AssigneeAcktar Ltd.
InventorsDina Katsir, Uri Zarnitsky
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Abstract
In an anodized electrode which comprises a substrate, a vacuum deposited porous coating thereon comprising at least one substance selected from valve metals, valve metal oxides and mixtures thereof, and at least one ectrolytically produced anodized layer selected from valve metal oxides and mixtures thereof, the effective surface area is increased prior to deposition of the at least one anodized layer, e.g. by oxidizing the surface of the porous layer and removing thus formed oxide, and/or by roughening the surface of substrate mechanically, chemically and/or electrochemically, prior to vapor deposition.
Claims24
A method for preparing an anodized electrode comprising the sequential steps of:
- (1) providing a substrate;
- (2) coating the surface of the substrate by vacuum deposition thereon of a porous coating comprising at least one substance selected from valve metals, valve metal oxides and mixtures thereof;
- (3) increasing the effective surface area of the porous coating;
- and
- (4) producing electrolytically at least one anodized valve oxide layer overlaying the surface of the porous coating.
A method for preparing an anodized electrode which includes pores having a branched morphology, comprising the sequential steps of:
- (1) providing a metallic foil substrate;
- (2) coating the surface of the substrate by vacuum deposition thereon of aluminum vapor in presence of a minor amount of oxygen such that a porous layer, consisting essentially of an aluminum metal component and an aluminum oxide component, is deposited on the substrate;
- (3) increasing the effective surface area of the porous coating by electrolytic anodization in presence of an electrolyte which comprises a saturated dicarboxylic acid salt selected from the ammonium and alkali metal salts, and removing thus-formed valve metal oxide(s), as well as at least part of the aluminum oxide component, by use of a halogen-free chemical etchant in situ or in a discrete subsequent sub-step;
- and
- (4) producing electrolytically at least one anodized aluminum oxide layer overlaying the surface of the porous coating.
An anodized electrode comprising:
- a substrate;
- a porous coating on the surface of said substrate produced by vacuum deposition thereon, said porous coating comprising at least one substance selected from valve metals, valve metal oxides and mixtures thereof;
- and
- at least one electrolytically produced anodized layer selected from valve metal oxides and mixtures thereof;
- wherein in said porous coating, the effective surface area has been increased prior to deposition of said at least one anodized layer.
An anodized electrode which comprises non-cylindrical pores having a branched morphology.
Dependencies are inferred from the claim text.