Nb solid electrolytic capacitor and method for preparing the same

A method for preparing an Nb solid electrolytic capacitor, said method comprising steps of:

• (A) forming an anode body from an Nb-based material, said anode body having a nitrogen content of about 7,500 ppm to about 47,000 ppm;
• (B) forming a dielectric layer over the surface of the anode body;
• (C) forming a solid electrolyte layer on the dielectric layer;
• and
• (D) forming a cathode body on the electrolyte layer.

A method for preparing an Nb solid electrolytic capacitor, said method comprising steps of:

• (H) forming a dielectric layer by anodic oxidation method over the surface of an anode body made from an Nb-based material;
• (I) heating the anode body provided with the dielectric layer at a temperature of about 100° C. to about 300° C.;
• (J) re-subjecting the product resulting from the step (I) to anodic oxidation;
• (K) forming a solid electrolyte layer on the dielectric layer;
• and
• (L) forming a cathode body on the solid electrolyte layer.

An Nb solid electrolytic capacitor comprising:

• a dielectric layer formed by anodic oxidation method over the surface of the anode body made from an Nb-based material, said anode body provided with the dielectric layer being heated at a temperature of about 100° C. to about 300° C. and then being re-subjected to anodic oxidation;
• a solid electrolyte layer formed on the dielectric layer;
• and
• a cathode body formed on the solid electrolyte layer.