Solid electrolytic capacitors with improved reliability

1. A solid electrolytic capacitor comprising:

an anode;

a dielectric on said anode;

a cathode on said dielectric;

a plated metal layer;

a blocking layer between said cathode and said plated metal layer; and

further comprising a metal filled layer between said cathode and said plated metal layer.

2. The solid electrolytic capacitor of claim 1 wherein said metal filled layer is between said cathode and said blocking layer.

3. The solid electrolytic capacitor of claim 1 wherein said metal filled layer comprises silver.

4. The solid electrolytic capacitor of claim 1 wherein said plated metal layer is a plated nickel layer.

5. The solid electrolytic capacitor of claim 4 wherein said plated metal layer consist essentially of nickel.

6. The solid electrolytic capacitor of claim 1 wherein said plated metal layer has a thickness of 2 microns to 100 microns.

7. The solid electrolytic capacitor of claim 1 wherein said blocking layer is selected from a group consisting of a hydrophobic layer, an insulative layer and a layer comprising carbon in a crosslinked matrix.

8. The solid electrolytic capacitor of claim 7 wherein said hydrophobic layer further comprises at least one of a polyhedral oligomeric silesquioxane, silica and nanoclay coated with hydrophobic polymers.

9. The solid electrolytic capacitor of claim 7 wherein said hydrophobic layer comprises a crosslinked polymer.

10. The solid electrolytic capacitor of claim 9 wherein said hydrophobic layer comprises conductive carbon.

11. The solid electrolytic capacitor of claim 7 wherein said insulative coating comprises at least one of a hydrophobic polymer and a hydrophobic additive.

12. The solid electrolytic capacitor of claim 7 wherein said insulative coating comprises a thermoset polymer.

13. The solid electrolytic capacitor of claim 1 further comprising a first conductive carbon layer.

14. The solid electrolytic capacitor of claim 13 further comprising a second conductive layer.

15. The solid electrolytic capacitor of claim 14 wherein said second conductive layer is a second conductive carbon layer.

16. The solid electrolytic capacitor of claim 15 wherein at least one of said first conductive carbon layer and said second conductive carbon layer comprises carbon particles selected from the group consisting of graphite, carbon black, carbon nanotubes and graphene.

17. The solid electrolytic capacitor of claim 14 wherein said blocking layer is between said first conductive carbon layer and said second conductive layer.

18. The solid electrolytic capacitor of claim 14 wherein said second conductive layer further comprises metal particles.

19. The solid electrolytic capacitor of claim 18 wherein said metal particles are silver particles.

20. The solid electrolytic capacitor of claim 18 wherein said second conductive layer comprises at least 5% resin by dry weight.

21. The solid electrolytic capacitor of claim 18 wherein said second conductive layer comprises at least 20% resin by dry weight.

22. The solid electrolytic capacitor of claim 14 wherein said blocking layer is between said first conductive carbon layer and a metal filled layer.

23. The solid electrolytic capacitor of claim 14 wherein said blocking layer is between a first metal filled layer and a second metal filled layer.

24. The solid electrolytic capacitor of claim 1 wherein said blocking layer comprises a polymer.

25. The solid electrolytic capacitor of claim 24 wherein said polymer is a polymer of at least one monomer selected from fluorinated monomer and silicone monomer.

26. The solid electrolytic capacitor of claim 1 wherein said blocking layer prevents diffusion of electrolyte into said anode.

27. The solid electrolytic capacitor of claim 1 wherein said cathode comprises at least one of MnO 2 or a conducting polymer.

28. The solid electrolytic capacitor of claim 1 wherein said blocking layer encases said cathode and said dielectric.

29. The solid electrolytic capacitor of claim 28 wherein said blocking layer encases a portion of an anode wire.

30. The solid electrolytic capacitor of claim 1 wherein said blocking layer is less than two microns thick.

31. The solid electrolytic capacitor of claim 1 further comprising a cathode lead in electrical contact with said plated metal layer.

32. The solid electrolytic capacitor of claim 1 with an ESR of less than 20 mohm.

33. A solid electrolytic capacitor comprising:

an anode;

a dielectric on said anode;

a conductive polymeric cathode on said dielectric;

a plated metal layer;

a blocking layer between said conductive polymeric cathode and said plated metal layer wherein said blocking layer comprises carbon in a crosslinked matrix; and

further comprising a metal filled layer between said cathode and said plated metal layer.

34. The solid electrolytic capacitor of claim 33 wherein said metal filled layer is between said cathode and said blocking layer.

35. The solid electrolytic capacitor of claim 33 wherein said metal filled layer comprises silver.

36. The solid electrolytic capacitor of claim 33 wherein said plated metal layer is a plated nickel layer.

37. The solid electrolytic capacitor of claim 36 wherein said plated metal layer consist essentially of nickel.

38. The solid electrolytic capacitor of claim 33 wherein said plated metal layer has a thickness of 2 microns to 100 microns.

39. The solid electrolytic capacitor of claim 33 wherein said blocking layer is selected from a group consisting of a hydrophobic layer, an insulative layer and a layer comprising carbon in a crosslinked matrix.

40. The solid electrolytic capacitor of claim 39 wherein said hydrophobic layer further comprises at least one of a polyhedral oligomeric silesquioxane, silica and nanoclay coated with hydrophobic polymers.

41. The solid electrolytic capacitor of claim 40 wherein said hydrophobic layer comprises a crosslinked polymer.

42. The solid electrolytic capacitor of claim 41 wherein said hydrophobic layer comprises conductive carbon.

43. The solid electrolytic capacitor of claim 40 wherein said insulative coating comprises at least one of a hydrophobic polymer and a hydrophobic additive.

44. The solid electrolytic capacitor of claim 40 wherein said insulative coating comprises a thermoset polymer.

45. The solid electrolytic capacitor of claim 33 further comprising a first conductive carbon layer.

46. The solid electrolytic capacitor of claim 45 further comprising a second conductive layer.

47. The solid electrolytic capacitor of claim 46 wherein said second conductive layer is a second conductive carbon layer.

48. The solid electrolytic capacitor of claim 47 wherein at least one of said first conductive carbon layer and said second conductive carbon layer comprises carbon particles selected from the group consisting of graphite, carbon black, carbon nanotubes and graphene.

49. The solid electrolytic capacitor of claim 46 wherein said blocking layer is between said first conductive carbon layer and said second conductive layer.

50. The solid electrolytic capacitor of claim 46 wherein said second conductive layer further comprises metal particles.

51. The solid electrolytic capacitor of claim 50 wherein said metal particles are silver particles.

52. The solid electrolytic capacitor of claim 50 wherein said second conductive layer comprises at least 5% resin by dry weight.

53. The solid electrolytic capacitor of claim 50 wherein said second conductive layer comprises at least 20% resin by dry weight.

54. The solid electrolytic capacitor of claim 46 wherein said blocking layer is between said first conductive carbon layer and a metal filled layer.

55. The solid electrolytic capacitor of claim 46 wherein said blocking layer is between a first metal filled layer and a second metal filled layer.

56. The solid electrolytic capacitor of claim 33 wherein said blocking layer comprises a polymer.

57. The solid electrolytic capacitor of claim 56 wherein said polymer is a polymer of at least one monomer selected from fluorinated monomer and silicone monomer.

58. The solid electrolytic capacitor of claim 33 wherein said blocking layer prevents diffusion of electrolyte into said anode.

59. The solid electrolytic capacitor of claim 33 wherein said blocking layer encases said cathode and said dielectric.

60. The solid electrolytic capacitor of claim 59 wherein said blocking layer encases a portion of an anode wire.

61. The solid electrolytic capacitor of claim 33 wherein said blocking layer is less than two microns thick.

62. The solid electrolytic capacitor of claim 33 further comprising a cathode lead in electrical contact with said plated metal layer.

63. The solid electrolytic capacitor of claim 33 with an ESR of less than 20 mohm.