CONDUCTIVE POLYMER DISPERSIONS FOR SOLID ELECTROLYTIC CAPACITORS

• US 20120300370A1
• Filed: 05/24/2012
• Published: 11/29/2012
• Est. Priority Date: 05/24/2011
• Status: Active Grant

• Current Assignee: Kemet Electronics Corporation (Yageo Corporation)
• Original Assignee: Kemet Electronics Corporation (Yageo Corporation)
• Inventors: Chacko, Antony
• Granted Patent: US 8,902,567 B2
• Time in Patent Office: Days
• US Class Current: 361/528
• CPC Class Codes: H01G 9/0032 formation of the dielectric layer
• CPC Class Codes: H01G 9/0036 Formation of the solid electrolyte layer
• CPC Class Codes: H01G 9/028 Organic semiconducting electrolytes, e.g. TCNQ
• CPC Class Codes: H01G 9/042 characterised by the material H01G11/22 takes precedence
• CPC Class Codes: H01G 9/048 characterised by their structure H01G11/22 takes precedence
• CPC Class Codes: H01G 9/15 Solid electrolytic capacitors H01G11/00 takes precedence

Abstract

A capacitor with an anode and a dielectric over the anode. A first conductive polymer layer is over the dielectric wherein the first conductive polymer layer comprises a polyanion and a first binder. A second conductive polymer layer is over the first conductive polymer layer wherein the second conductive polymer layer comprises a polyanion and a second binder and wherein the first binder is more hydrophilic than the second binder.

Claims

1. A capacitor comprising:

an anode;

a dielectric over said anode;

a conductive polymer layer over said dielectric;

wherein said conductive polymer layer has a moisture content of at least 16 wt % and a moisture loss of no more than 5 wt % upon heating from 125°

C. to 175°

C.

2. The capacitor of claim 1 wherein said moisture content is at least 21 wt %.

3. The capacitor of claim 2 wherein said moisture content is at least 24 wt %.

4. The capacitor of claim 3 wherein said moisture content is at least 27 wt %.

5. The capacitor of claim 1 wherein said moisture loss is less than 3 wt %.

6. The capacitor of claim 5 wherein said moisture loss is less than 1 wt %.

7. The capacitor of claim 1 wherein said conductive polymer layer comprises a moisture retaining compound.

8. The capacitor of claim 7 wherein said moisture retaining compound is selected from the group consisting of a hydrogel, a molecular sieve and a molecular container.

9. The capacitor of claim 8 wherein said molecular sieve is zeolite.

10. The capacitor of claim 8 wherein said molecular container is cyclodextrin or a derivative thereof.

11. The capacitor of claim 8 wherein said hydrogel is crosslinked.

12. The capacitor of claim 11 wherein said hydrogel is crosslinked with a conductive polymer of said conductive polymer layer.

13. The capacitor of claim 11 wherein said hydrogel is crosslinked with a crosslinking agent.

14. The capacitor of claim 13 wherein said crosslinking agent comprises functional groups selected from hydroxyl and carboxyl.

15. The capacitor of claim 7 wherein at least said moisture retaining component is encapsulated in a binder.

16. The capacitor of claim 15 wherein said binder has a Tg of at least 100°

C.

17. The capacitor of claim 16 wherein said binder has a Tg of at least 150°

C.

18. The capacitor of claim 1 further comprising an adhesive layer wherein said adhesive layer comprises at least one carbon layer wherein said carbon layer comprises at least one material selected from the group consisting of a hydrophobic compound and a moisture retaining compound.

19. A capacitor comprising:

an anode

a dielectric over said anode;

a first conductive polymer layer over said dielectric wherein said first conductive polymer layer comprises a polyanion and a first binder; and

a second conductive polymer layer over said first conductive polymer layer wherein said second conductive polymer layer comprises a polyanion and a second binder wherein said first binder is more hydrophilic than said second binder.

20. The capacitor of claim 19 wherein said first conductive polymer layer has a moisture content of at least 21 wt %.

21. The capacitor of claim 19 wherein said second conductive polymer layer has a moisture content of no more than 15 wt % at 125°

C.

22. The capacitor of claim 19 wherein said first binder is a hydrophilic polymer.

23. The capacitor of claim 19 wherein said first binder is a hydrophilic material selected from the group consisting of poly(ethylene oxide), poly(vinyl alcohol), hydroxylethyl cellulose, polyvinylpyrrolidone, poly(hydroxyethyl methacrylate), polyurethane, poly(ethyleneglycol), poly(propylene glycol), poly(vinylpyrrolidone), Xanthan, methyl cellulose, starch, poly(vinylpyrrolidone), poly(acrylic acid), carboxymethyl cellulose, hydroxypropyl methyl cellulose, polyvinyl alcohol, acrylic acid, methacrylic acid, chitosan, α

β

-glycerophosphate, hydrophilic polyester, polyphosphazene, polypeptide, chitosan, poly(vinyl methyl ether) and poly(N-isopropyl acrylamide).

24. The capacitor of claim 23 wherein said first binder is at least one hydrophilic material selected from the group consisting of poly(ethylene oxide), poly(vinyl alcohol) and hydroxylethyl cellulose.

25. The capacitor of claim 23 wherein said hydrophilic material is crosslinked.

26. The capacitor of claim 23 wherein said hydrophilic material is crosslinked with a crosslinking agent.

27. The capacitor of claim 26 wherein said crosslinking agent comprises functional groups selected from hydroxyl and carboxyl.

28. The capacitor of claim 25 wherein said hydrophilic material is crosslinked with a conductive polymer of said first conductive polymer layer.

29. The capacitor of claim 19 wherein said second binder is a hydrophobic material.

30. The capacitor of claim 29 wherein said hydrophobic material is selected from the group consisting of thermosetting materials, fluoro-polymers and their copolymers, silicone polymers and their copolymers, silicone polyester, crosslinkable polyester and crosslinkable epoxies.

31. The capacitor of claim 30 wherein said hydrophobic material is polytetrafluoroethylene.

32. The capacitor of claim 19 wherein at least one of said first conductive polymer layer or said second conductive polymer layer comprises a moisture retaining component.

33. The capacitor of claim 32 wherein said moisture retaining component is a material selected from the group consisting of a hydrogel, a molecular sieve, and a molecular container.

34. The capacitor of claim 32 wherein at least said moisture retaining component is encapsulated in a polymeric encapsulant.

35. The capacitor of claim 34 wherein said polymeric encapsulant has a Tg of at least 100°

C.

36. The capacitor of claim 35 wherein said polymeric encapsulant has a Tg of at least 150°

C.

37. The capacitor of claim 19 wherein at least one of said first conductive polymer layer or said second conductive polymer layer has a moisture loss of no more than 5 wt % upon heating from 125°

C. to 175°

C.

38. The capacitor of claim 37 wherein said moisture loss is no more than 3 wt %.

39. The capacitor of claim 37 wherein said moisture loss is no more than 1 wt %.

40. The capacitor of claim 19 wherein said first conductive polymer layer has a moisture content which is at least 110 wt % of a moisture content of said second conductive polymer layer.

41. The capacitor of claim 40 wherein said first conductive polymer layer has a moisture content which is at least 150 wt % of the moisture content of said second conductive polymer layer.

42. The capacitor of claim 41 wherein said first conductive polymer layer has a moisture content which is at least 200 wt % of the moisture content of said second conductive polymer layer.

43. The capacitor of claim 19 further comprising an adhesive layer wherein said adhesive layer comprises at least one carbon layer wherein said carbon layer comprises at least one material selected from the group consisting of a hydrophobic compound and a moisture retaining compound.

44. A capacitor comprising:

an anode

a dielectric over said anode;

a first conductive polymer layer over said dielectric wherein said first conductive polymer layer comprises a binder and a polyanion and said first conductive polymer layer has a first moisture content;

a second conductive polymer layer over said first conductive polymer layer wherein said second conductive polymer layer comprises a binder and a polyanion and said second conductive polymer layer has a second moisture content; and

wherein said first moisture content is at least 5 wt % higher than said second moisture content.

45. The capacitor of claim 44 wherein said first conductive polymer layer has a moisture content of at least 21 wt %.

46. The capacitor of claim 44 wherein said second conductive polymer layer has a moisture content of no more than 15 wt %.

47. The capacitor of claim 44 wherein said first conductive polymer layer comprises a hydrophilic polymer.

48. The capacitor of claim 44 wherein said first conductive polymer layer comprises a hydrophilic material selected from the group consisting of poly(ethylene oxide), poly(vinyl alcohol), hydroxylethyl cellulose, polyvinylpyrrolidone, poly(hydroxyethyl methacrylate), polyurethane, poly(ethyleneglycol), poly(propylene glycol), poly(vinylpyrrolidone), Xanthan, methyl cellulose, starch, poly(vinylpyrrolidone), poly(acrylic acid), carboxymethyl cellulose, hydroxypropyl methyl cellulose, polyvinyl alcohol, acrylic acid, methacrylic acid, chitosan, α

β

-glycerophosphate, hydrophilic polyester, polyphosphazene, polypeptide, chitosan, poly(vinyl methyl ether) and poly(N-isopropyl acrylamide).

49. The capacitor of claim 48 wherein said first conductive polymer layer comprises at least one hydrophilic material selected from the group consisting of poly(ethylene oxide), poly(vinyl alcohol) and hydroxylethyl cellulose.

50. The capacitor of claim 48 wherein said hydrophilic material is crosslinked.

51. The capacitor of claim 50 wherein said hydrophilic material is crosslinked with a crosslinking agent.

52. The capacitor of claim 51 wherein said crosslinking agent comprises functional groups selected from hydroxyl and carboxyl.

53. The capacitor of claim 50 wherein said hydrophilic material is crosslinked with a conductive polymer of said first conductive polymer layer.

54. The capacitor of claim 44 wherein said second conductive polymer comprises a hydrophobic material.

55. The capacitor of claim 54 wherein said hydrophobic material is selected from the group consisting of thermosetting materials, fluoro-polymers and their copolymers, silicone polymers and their copolymers, silicone polyester, crosslinkable polyester and crosslinkable epoxies.

56. The capacitor of claim 55 wherein said hydrophobic material is polytetrafluoroethylene.

57. The capacitor of claim 44 wherein at least one of said first conductive polymer or said second conductive polymer comprises a moisture retaining component.

58. The capacitor of claim 57 wherein said moisture retaining component is a material selected from the group consisting of a hydrogel, a molecular sieve, and a molecular container.

59. The capacitor of claim 57 wherein at least said moisture retaining component is encapsulated in a polymeric encapsulant.

60. The capacitor of claim 59 wherein said polymeric encapsulant has a Tg of at least 100°

C.

61. The capacitor of claim 60 wherein said polymeric encapsulant has a Tg of at least 150°

C.

62. The capacitor of claim 44 wherein at least one of said first conductive polymer layer or said second conductive polymer layer has a moisture loss of no more than 5 wt % upon heating from 125°

C. to 175°

C.

63. The capacitor of claim 62 wherein said moisture loss is no more than 3 wt %.

64. The capacitor of claim 62 wherein said moisture loss is no more than 1 wt %.

65. The capacitor of claim 44 wherein said first conductive polymer layer has a moisture content which is at least 110 wt % of a moisture content of said second conductive polymer layer.

66. The capacitor of claim 65 wherein said first conductive polymer layer has a moisture content which is at least 150 wt % of the moisture content of said second conductive polymer layer.

67. The capacitor of claim 66 wherein said first conductive polymer layer has a moisture content which is at least 200 wt % of the moisture content of said second conductive polymer layer.

68. The capacitor of claim 44 further comprising an adhesive layer wherein said adhesive layer comprises at least one carbon layer wherein said carbon layer comprises at least one material selected from the group consisting of a hydrophobic compound and a moisture retaining compound.

69. A capacitor comprising:

an anode;

a dielectric over said anode;

a first polymer layer over said dielectric;

a second polymer over said first polymer layer wherein said first polymer layer and said second polymer layer has a moisture loss of less than 5 wt % upon heating from 125°

C. to 175°

C.

70. The capacitor of claim 69 wherein the moisture loss is less than 3 wt %.

71. The capacitor of claim 70 wherein the moisture loss is less than 1 wt %.

72. The capacitor of claim 69 wherein said first polymer layer has a higher moisture content than said second polymer layer.

73. A method for forming a capacitor comprising:

providing an anode with a dielectric coating thereon;

applying a first dispersion over said dielectric thereby forming a first conductive polymer layer over said dielectric coating wherein said first conductive polymer layer comprises a dopant and a hydrophilic material; and

applying a second dispersion over said first conductive polymer layer thereby forming a second conductive polymer layer over said first conductive polymer layer.

74. The method for forming a capacitor of claim 73 wherein said second conductive polymer layer comprises a hydrophobic material.

75. The method for forming a capacitor of claim 74 wherein said hydrophobic material is selected from the group consisting of thermosetting materials, fluoro-polymers and their copolymers, silicone polymers and their copolymers, silicone polyester, crosslinkable polyester and crosslinkable epoxies.

76. The method for forming a capacitor of claim 75 wherein said hydrophobic material is polytetrafluoroethylene.

77. The method for forming a capacitor of claim 73 wherein said first conductive polymer layer has a moisture content of at least 21 wt %.

78. The method for forming a capacitor of claim 73 wherein said second conductive polymer layer has a moisture content of no more than 15 wt % at 125°

C.

79. The method for forming a capacitor of claim 73 wherein said hydrophilic material selected from the group consisting of poly(ethylene oxide), poly(vinyl alcohol), hydroxylethyl cellulose, polyvinylpyrrolidone, poly(hydroxyethyl methacrylate), polyurethane, poly(ethyleneglycol), poly(propylene glycol), poly(vinylpyrrolidone), Xanthan, methyl cellulose, starch, poly(vinylpyrrolidone), poly(acrylic acid), carboxymethyl cellulose, hydroxypropyl methyl cellulose, polyvinyl alcohol, acrylic acid, methacrylic acid, chitosan, α

β

-glycerophosphate, hydrophilic polyester, polyphosphazene, polypeptide, chitosan, poly(vinyl methyl ether) and poly(N-isopropyl acrylamide).

80. The method for forming a capacitor of claim 79 wherein said first conductive polymer layer comprises at least one hydrophilic material selected from the group consisting of poly(ethylene oxide), poly(vinyl alcohol) and hydroxylethyl cellulose.

81. The method for forming a capacitor of claim 79 wherein said hydrophilic material is crosslinked.

82. The method for forming a capacitor of claim 81 wherein said hydrophilic material is crosslinked with a crosslinking agent.

83. The method for forming a capacitor of claim 82 wherein said crosslinking agent comprises functional groups selected from hydroxyl and carboxyl.

84. The method for forming a capacitor of claim 81 wherein said hydrophilic material is crosslinked with a conductive polymer of said first conductive polymer layer.

85. The method for forming a capacitor of claim 73 wherein at least one of said first conductive polymer or said second conductive polymer comprises a moisture retaining component.

86. The method for forming a capacitor of claim 85 wherein said moisture retaining component is a material selected from the group consisting of a hydrogel, a molecular sieve, and a molecular container.

87. The method for forming a capacitor of claim 85 wherein at least said moisture retaining component is encapsulated in a polymeric encapsulant.

88. The method for forming a capacitor of claim 87 wherein said polymeric encapsulant has a Tg of at least 100°

C.

89. The method for forming a capacitor of claim 88 wherein said polymeric encapsulant has a Tg of at least 150°

C.

90. The method for forming a capacitor of claim 73 wherein at least one of said first conductive polymer layer or said second conductive polymer layer has a moisture loss of no more than 5 wt % upon heating from 125°

C. to 175°

C.

91. The method for forming a capacitor of claim 90 wherein said moisture loss is no more than 3 wt %.

92. The method for forming a capacitor of claim 90 wherein said moisture loss is no more than 1 wt %.

93. The method for forming a capacitor of claim 73 wherein said first conductive polymer layer has a moisture content which is at least 110 wt % of a moisture content of said second conductive polymer layer.

94. The method for forming a capacitor of claim 93 wherein said first conductive polymer layer has a moisture content which is at least 150 wt % of the moisture content of said second conductive polymer layer.

95. The method for forming a capacitor of claim 94 wherein said first conductive polymer layer has a moisture content which is at least 200 wt % of the moisture content of said second conductive polymer layer.

96. A capacitor comprising:

an anode

a dielectric over said anode;

a first conductive polymer layer over said dielectric wherein said first conductive polymer layer has a moisture content of at least 20 wt %; and

a second conductive polymer layer over said first conductive polymer layer wherein said second conductive polymer layer comprises at least one material selected from a hydrophobic material and a moisture retaining compound.

97. The capacitor of claim 96 wherein said first conductive polymer layer has a moisture content of at least 21 wt %.

98. The capacitor of claim 96 wherein said second conductive polymer layer has a moisture content of no more than 15 wt % at 125°

C.

99. The capacitor of claim 96 wherein said first conductive polymer layer comprises a hydrophilic polymer.

100. The capacitor of claim 96 wherein said first conductive polymer layer comprises a hydrophilic material selected from the group consisting of poly(ethylene oxide), poly(vinyl alcohol), hydroxylethyl cellulose, polyvinylpyrrolidone, poly(hydroxyethyl methacrylate), polyurethane, poly(ethyleneglycol), poly(propylene glycol), poly(vinylpyrrolidone), Xanthan, methyl cellulose, starch, poly(vinylpyrrolidone), poly(acrylic acid), carboxymethyl cellulose, hydroxypropyl methyl cellulose, polyvinyl alcohol, acrylic acid, methacrylic acid, chitosan, α

β

-glycerophosphate, hydrophilic polyester, polyphosphazene, polypeptide, chitosan, poly(vinyl methyl ether) and poly(N-isopropyl acrylamide).

101. The capacitor of claim 100 wherein said first conductive polymer layer comprises at least one hydrophilic material selected from the group consisting of poly(ethylene oxide), poly(vinyl alcohol) and hydroxylethyl cellulose.

102. The capacitor of claim 100 wherein said hydrophilic material is crosslinked.

103. The capacitor of claim 102 wherein said hydrophilic material is crosslinked with a crosslinking agent.

104. The capacitor of claim 103 wherein said crosslinking agent comprises functional groups selected from hydroxyl and carboxyl.

105. The capacitor of claim 102 wherein said hydrophilic material is crosslinked with a conductive polymer of said first conductive polymer layer.

106. The capacitor of claim 96 wherein said hydrophobic material is selected from the group consisting of thermosetting materials, fluoro-polymers and their copolymers, silicone polymers and their copolymers, silicone polyester, crosslinkable polyester and crosslinkable epoxies.

107. The capacitor of claim 106 wherein said hydrophobic material is polytetrafluoroethylene.

108. The capacitor of claim 96 wherein said moisture retaining component is a material selected from the group consisting of a hydrogel, a molecular sieve, and a molecular container.

109. The capacitor of claim 96 wherein at least said moisture retaining component is encapsulated in a polymeric encapsulant.

110. The capacitor of claim 109 wherein said polymeric encapsulant has a Tg of at least 100°

C.

111. The capacitor of claim 110 wherein said polymeric encapsulant has a Tg of at least 150°

C.

112. The capacitor of claim 96 wherein at least one of said first conductive polymer layer or said second conductive polymer layer has a moisture loss of no more than 5 wt % upon heating from 125°

C. to 175°

C.

113. The capacitor of claim 112 wherein said moisture loss is no more than 3 wt %.

114. The capacitor of claim 112 wherein said moisture loss is no more than 1 wt %.

115. The capacitor of claim 96 wherein said first conductive polymer layer has a moisture content which is at least 110 wt % of a moisture content of said second conductive polymer layer.

116. The capacitor of claim 115 wherein said first conductive polymer layer has a moisture content which is at least 150 wt % of the moisture content of said second conductive polymer layer.

117. The capacitor of claim 116 wherein said first conductive polymer layer has a moisture content which is at least 200 wt % of the moisture content of said second conductive polymer layer.