Solid electrolytic capacitor for use at high temperatures

1. A capacitor comprising a capacitor element that includes an anode that contains a dielectric formed on a sintered porous body, a solid electrolyte overlying the anode, and a cathode coating that includes a noble metal layer overlying the solid electrolyte and a layer overlying the noble metal layer that includes sintered metal particles; and

wherein the capacitor exhibits a capacitance of about 30 nanoFarads per square centimeter or more and /or a dissipation factor of from about 1% to about 25%.

2. The capacitor of claim 1 , wherein the noble metal layer contains a noble metal having an electrical potential of about 0.7 V or more.

3. The capacitor of claim 1 , wherein the noble metal layer includes gold.

4. The capacitor of claim 1 , wherein the sintered metal particles include silver.

5. The capacitor of claim 1 , wherein the particles have an average size of from about 0.01 to about 50 micrometers.

6. The capacitor of claim 1 , wherein the anode body includes tantalum.

7. The capacitor of claim 1 , wherein the solid electrolyte includes manganese dioxide.

8. The capacitor of claim 1 , wherein the capacitor exhibits an equivalence series resistance of about 500 mohms or less.

9. The capacitor of claim 8 , wherein the capacitor exhibits a capacitance of about 30 nanoFarads per square centimeter or more, an equivalence series resistance of about 500 mohms or less, and/or a dissipation factor of from about 1% to about 25%, after being exposed to a temperature of 230° C. for about 500 hours.

10. The capacitor of claim 1 , further comprising a housing within which the capacitor element is enclosed.

11. The capacitor of claim 10 , wherein the housing is formed from a resinous material that encapsulates the capacitor element.

12. The capacitor of claim 10 , wherein the housing defines an interior cavity within which the capacitor element is positioned, wherein the interior cavity has a gaseous atmosphere.

13. The capacitor of claim 12 , wherein the gaseous atmosphere contains an inert gas.

14. A capacitor comprising a capacitor element that includes an anode that contains a dielectric formed on a sintered porous body, a solid electrolyte overlying the anode, and a cathode coating that includes a noble metal layer overlying the solid electrolyte and a layer overlying the noble metal layer that includes sintered metal particles; and

wherein the solid electrolyte includes manganese dioxide.

15. The capacitor of claim 14 , wherein the noble metal layer contains a noble metal having an electrical potential of about 0.7 V or more.

16. The capacitor of claim 14 , wherein the noble metal layer includes gold.

17. The capacitor of claim 14 , wherein the sintered metal particles include silver.

18. The capacitor of claim 14 , wherein the particles have an average size of from about 0.01 to about 50 micrometers.

19. The capacitor of claim 14 , wherein the anode body includes tantalum.

20. The capacitor of claim 14 , wherein the capacitor exhibits a capacitance of about 30 nanoFarads per square centimeter or more, an equivalence series resistance of about 500 mohms or less, and/or a dissipation factor of from about 1% to about 25%.

21. The capacitor of claim 20 , wherein the capacitor exhibits a capacitance of about 30 nanoFarads per square centimeter or more, an equivalence series resistance of about 500 mohms or less, and/or a dissipation factor of from about 1% to about 25%, after being exposed to a temperature of 230° C. for about 500 hours.

22. The capacitor of claim 14 , further comprising a housing within which the capacitor element is enclosed.

23. The capacitor of claim 22 , wherein the housing is formed from a resinous material that encapsulates the capacitor element.

24. The capacitor of claim 22 , wherein the housing defines an interior cavity within which the capacitor element is positioned, wherein the interior cavity has a gaseous atmosphere.

25. The capacitor of claim 24 , wherein the gaseous atmosphere contains an inert gas.