Solid electrolytic capacitors (e.g., tantalum capacitors) are typically made by pressing a metal powder (e.g., tantalum) around a metal lead wire, sintering the pressed part, anodizing the sintered anode, and thereafter applying a solid electrolyte. Intrinsically conductive polymers are often employed as the solid electrolyte due to their advantageous low equivalent series resistance (“ESR”) and “non-burning/non-ignition” failure mode. For example, such electrolytes can be formed through in situ chemical polymerization of a 3,4-dioxythiophene monomer (“EDOT”) in the presence of a catalyst and dopant. However, conventional capacitors that employ in situ polymerized polymers tend to have a relatively high leakage current (“DCL”) and fail at high voltages, such as experienced during a fast switch on or operational current spike. In an attempt to overcome these issues, dispersions have also been employed that are formed from a complex of poly(3,4-ethylenedioxythiophene) and poly(styrene sulfonic acid (“PEDOT:PSS”). While the PEDOT:PSS dispersions can result in lower leakage current values, the ability of the DCL to decrease over time after an applied voltage depends on the level of humidity in the capacitor. That is, capacitors having a high moisture content tend to exhibit a relatively fast DCL decay rate, but dry capacitors tend to exhibit a much slower DCL decay rate, especially at lower temperatures.
As such, a need currently exists for a solid electrolytic capacitor having an improved performance.