A capacitor that comprises a capacitor element is provided. The capacitor element comprises a deoxidized and sintered anode body that is formed from a powder having a specific charge of about 35,000 μF*V/g or more. Further, a dielectric overlies the anode body and a solid electrolyte overlies the dielectric. The capacitor also exhibits a normalized aged leakage current of about 0.1% or less.

A solid electrolytic capacitor comprising a capacitor element, anode lead extending from a surface of the capacitor element, an anode termination that is in electrical connection with the anode lead, a cathode termination that is in electrical connection with the solid electrolyte, and a casing material that encapsulates the capacitor element and anode lead is provided. A barrier coating is disposed on at least a portion of the capacitor element and is in contact with the casing material. The coating contains a polymeric material that includes a fluorinated component and a non-fluorinated component. The polymeric material has a glass transition temperature of from about 10° C. to about 120° C. and a thermal decomposition temperature of about 200° C. to about 300° C.

A capacitor 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 comprises a sintered porous anode body formed from a powder having a specific charge of about 100,000 μF*V/g or more; a dielectric that overlies the anode body; and a solid electrolyte that overlies the dielectric. The solid electrolyte contains an in situ-polymerized conductive polymer. Further, the capacitor exhibits a leakage current of about 110 microamps or less at a temperature of about 23° C. after being subjected to an applied rated voltage.

An improved process for forming powder, an anode of the powder and a capacitor comprising the powder is provided. The process comprises forming a dense aggregate comprising a powder and solvent in a pendular, funicular or capillary state and freeze drying the powder comprising high surface area.

A wet tantalum electrolytic capacitor containing a cathode, fluidic working electrolyte, and anode formed from an anodically oxidized sintered porous tantalum pellet is provided. The pellet is formed from a pressed tantalum powder. The tantalum powder is formed by reacting a tantalum oxide compound, for example, tantalum pentoxide, with a reducing agent that contains a metal having an oxidation state of 2 or more, for example, magnesium. The resulting tantalum powder is nodular or angular and has a specific charge that ranges from about 11,000 μF*V/g to about 14,000 μF*V/g. Using this powder, wet tantalum electrolytic capacitors have breakdown voltages that ranges from about 250 volts to about 400 volts. This makes the electrolytic capacitors ideal for use in an implantable medical device.

An improved capacitor is provided wherein the capacitor has an improved bond between the anode and anode wire. The anode comprises a pressed anode powder comprising a first density region and a second density region wherein the second density region has a higher density than the first density region. An anode wire extends into the second density region wherein the anode wire in the second density region is distorted by compression. This allows for better utilization of the metal powder surface area by allowing a lower bulk press density and lower sinter temperature while still achieving the necessary wire pull strength. In addition, this invention when utilized with deoxidation steps, results in sufficient wire pull strengths not possible otherwise.

Provided is a method for producing an electrode for an electrolytic capacitor, the method comprising: a hydration step in which an aluminum electrode is immersed in a hydration treatment solution having a temperature of 80° C. or higher; and a chemical conversion step in which the aluminum electrode is subjected to chemical conversion treatment up to a formation voltage of at least 400 V. The hydration treatment solution contains a hydration inhibitor. The thickness of a hydrated film formed in the hydration step satisfies the following condition, 0.6≤t2/t1≤1, wherein t1 is the average thickness of the hydrated film formed in a depth range of up to 100 μm from the surface of the aluminum electrode, and t2 is the average thickness s of the hydrated film formed in a deep portion at least 100 μm from the surface of the aluminum electrode.

Provided is an improved capacitor formed by a process comprising: providing an anode comprising a dielectric thereon wherein the anode comprises a sintered powder wherein the powder has a powder charge of at least 45,000 μFV/g; and forming a first conductive polymer layer encasing at least a portion of the dielectric by applying a first slurry wherein the first slurry comprises a polyanion and a conductive polymer and wherein the polyanion and conductive polymer are in a weight ratio of greater than 3 wherein the conductive polymer and polyanion forms conductive particles with an average particle size of no more than 20 nm.

Anodes made from powder, such as tantalum powder, that is highly spherical is described. Methods to make the anodes are further described.

An improved capacitor is provided. The capacitor comprises an anode comprising a pressed and sintered, preferably tantalum, powder wherein the anode has edge surfaces and parallel major surfaces. The anode further comprises a first set of parallel surface protrusions and a second set of parallel surface protrusions on each parallel major surface wherein the first set of parallel surface protrusions and second set of parallel surface protrusions are not parallel and form a well therebetween. An anode wire extends from an edge surface of the edge surfaces. A dielectric is on the anode and a conductive polymer on said dielectric.