Solid electrolytic capacitor with improved leakage current
AssigneeAVX Corporation
InventorsIssei Nakata, Jan Petrzilek, Miloslav Uher, Tomas Hofirek
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Abstract
A capacitor assembly that is capable of exhibiting good electrical properties even under a variety of conditions is provided. More particularly, the capacitor contains a capacitor element that includes a sintered porous anode body, a dielectric that overlies the anode body, and a solid electrolyte that overlies the dielectric. The solid electrolyte contains an adhesion layer that is positioned between an inner conductive polymer layer and an outer conductive polymer layer. The adhesion layer is formed from an organometallic compound and the outer layer is formed from pre-polymerized conductive polymer particles.
Claims25
A capacitor assembly comprising a capacitor element, the capacitor element comprising:
- a sintered porous anode body;
- a dielectric that overlies the anode body;
- a solid electrolyte that overlies the dielectric and contains an adhesion layer positioned between an inner conductive polymer layer and an outer conductive polymer layer, wherein the adhesion layer is formed from an organometallic compound, wherein the outer conductive polymer layer is formed from a dispersion of pre-polymerized conductive polymer particles that contain a polymeric counterion and an extrinsically conductive polymer, wherein the extrinsically conductive polymer is poly(3,4-ethylenedioxythiophene), and wherein 70 wt. % or more of the outer conductive polymer layer is formed from the pre-polymerized conductive polymer particles.
A method for forming a capacitor assembly, the method comprising:
- anodically oxidizing a sintered porous anode body to form a dielectric that overlies the sintered porous anode body;
- polymerizing a conductive polymer precursor monomer in the presence of an oxidative catalyst to form an inner solid electrolyte layer that overlies the dielectric;
- applying a solution that includes an organometallic compound to form an adhesion layer that overlies the inner solid electrolyte layer, wherein the organometallic compound has the following general formula:
- wherein,
- M is an organometallic atom;
- R1, R2, and R3 are independently an alkyl or a hydroxyalkyl, wherein at least one of R1, R2, and R3 is a hydroxyalkyl;
- n is an integer from 0 to 8;
- and
- X is an organic or inorganic functional group;
- and
- applying a dispersion of conductive polymer particles to form an outer solid electrolyte layer that overlies the adhesion layer, and wherein the outer solid electrolyte layer is formed from a dispersion of pre-polymerized conductive polymer particles that contain a polymeric counterion and an extrinsically conductive polymer, wherein the extrinsically conductive polymer is poly(3,4-ethylenedioxythiophene), and wherein 70 wt. % or more of the outer solid electrolyte layer is formed from the conductive polymer particles.
Dependencies are inferred from the claim text.