Polyanion copolymers for use with conducting polymers in solid electrolytic capacitors

Patent metadata

Field	Value
Publication number	US-10340091-B2
Application number	US-201715595137-A
Country	US
Kind code	B2
Filing date	May 15, 2017
Priority date	May 19, 2016
Publication date	Jul 2, 2019
Grant date	Jul 2, 2019

Abstract

A capacitor and a method of making a capacitor, is provided with improved reliability performance. The capacitor comprises an anode; a dielectric on the anode; and a cathode on the dielectric wherein the cathode comprises a conductive polymer and a polyanion wherein the polyanion is a copolymer comprising groups A, B and C represented by Formula A x B y C z as described herein.

First claim

The invention claimed is:

1. A capacitor comprising:
an anode;
a dielectric on said anode; and
a cathode on said dielectric wherein cathode comprises:
a conductive polymer; and
a polyanion wherein said polyanion is a copolymer comprising groups A, B and C represented by the ratio of Formula A:
A x B y C z    Formula A

wherein:
A is polystyrenesulfonic acid or a salt of polystyrenesulfonate;
B and C separately represent polymerized units substituted by a group selected from:
-Carboxyl group;
—C(O)OR 6 group wherein R 6 is selected from the group consisting of:
an alkyl of 1 to 20 carbons optionally substituted with a functional group selected from the group consisting of hydroxyl, carboxyl, amine, epoxy, silane, amide, phosphate, imide, thiol, alkene, alkyne, azide, acrylate, anhydride and
—(CHR 7 CH 2 O) b —R 8 wherein:
R 7 is selected from a hydrogen or an alkyl of 1 to 7 carbons;
b is an integer from 1 to the number sufficient to provide a molecular weight of up to 200,000 for the CHR 7 CH 2 O— group;
R 8 is selected from the group consisting of hydrogen, an alkyl of 1 to 9 carbons optionally substituted with a functional group selected from the group consisting of hydroxyl, carboxyl, amine, epoxy, silane, amide, phosphate, imide, thiol, alkene, alkyne, azide, acrylate and anhydride;

—C(O)—NHR 9 group wherein:
R 9 is a hydrogen or an alkyl of 1 to 20 carbons optionally substituted with a functional group selected from the group consisting of hydroxyl, carboxyl, amine, epoxy, silane, amide, alcohol, phosphate, imide, thiol, alkene, alkyne, azide, acrylate and anhydride;

—C 6 H 4 —R 10 group wherein:
R 10 is selected from:
a hydrogen or an alkyl optionally substituted with a functional group selected from the group consisting of hydroxyl, carboxyl, amine, epoxy, silane, amide, phosphate, imide, thiol, alkene, alkyne, azide, acrylate and anhydride;

a reactive group selected from the group consisting of hydroxyl, carboxyl, amine, epoxy, silane, amide, phosphate, imide, thiol, alkene, alkyne, azide, acrylate, anhydride and
—(O(CHR 11 CH 2 O) d —R 12 wherein:

R 11 is a hydrogen or an alkyl of 1 to 7 carbons;
d is an integer from 1 to the number sufficient to provide a molecular weight of up to 200,000 for the CHR 11 CH 2 O— group;
R 12 is selected from the group consisting of hydrogen, an alkyl of 1 to 9 carbons optionally substituted with a functional group selected from the group consisting of hydroxyl, carboxyl, amine, epoxy, silane, amide, phosphate, imide, thiol, alkene, alkyne, azide, acrylate and anhydride;

C 6 H 4 —O—R 13 group wherein:
R 13 is selected from:
a hydrogen, an alkyl optionally substituted with a reactive group selected from the group consisting of hydroxyl, carboxyl, amine, epoxy, silane, amide, alcohol, phosphate and anhydride;

a reactive group selected from the group consisting of epoxy, silane, phosphate alkene, alkyne, azide, acrylate, anhydride and
—(CHR 14 CH 2 O) e —R 15 wherein:
R 14 is a hydrogen or an alkyl of 1 to 7 carbons;
e is an integer from 1 to the number sufficient to provide a molecular weight of up to 200,000 for the —CHR 14 CH 2 O— group;
R 15 is selected from the group consisting of a hydrogen and an alkyl of 1 to 9 carbons optionally substituted with a functional group selected from the group consisting of hydroxyl, carboxyl, amine, epoxy, silane, amide, phosphate, imide, thiol, alkene, alkyne, azide, acrylate and anhydride;

x, y and z, taken together are sufficient to form a polyanion with a molecular weight of at least 100 to no more than 500,000 and y/x is 0.01 to 100; z is 0 to a ratio z/x of no more than 100; and
with the proviso that when z is not zero C is not the same group as B and B is not a polymerized monomer of acrylate, methacrylate or an alkoxysilane.

2. The capacitor of claim 1 wherein said polyanion is a random copolymer.

3. The capacitor of claim 1 wherein at least one of R 7 , R 11 or R 14 is selected from hydrogen and methyl.

4. The capacitor of claim 1 wherein x represents 50-99%, y represents 1-50% and z represents 0-49% of the sum total of x+y+z.

5. The capacitor of claim 4 where x represents 70-90%; y represents 10-30% and z represents 0-20% of the sum total of x+y+z.

6. The capacitor of claim 1 wherein x represents 1-40%, y represents 60-99% and z represents 0-39% of the sum total of x+y+z.

7. The capacitor of claim 6 where x represents 5-40%; y represents 60-95% and z represents 0-35% of the sum total of x+y+z.

8. The capacitor of claim 1 wherein said polyanion is selected from the group consisting of:

9. The capacitor of claim 1 wherein said cathode comprises at least one internal layer and at least one external layer.

10. The capacitor of claim 9 wherein at least one said external layer comprises said polyanion.

11. The capacitor of claim 9 wherein said cathode comprises multiple external layers.

12. The capacitor of claim 11 wherein each said external layer of said external layers comprises said polyanion.

13. The capacitor of claim 1 wherein said conductive polymer is selected from the group consisting of polyaniline, polypyrrole and polythiophene.

14. The capacitor of claim 13 wherein said conductive polymer is conductive polymer comprises repeating units of Formula 1:

wherein:
R 1 and R 2 independently represent linear or branched C 1 -C 16 alkyl or C 2 -C 18 alkoxyalkyl; or are C 3 -C 8 cycloalkyl, phenyl or benzyl which are unsubstituted or substituted by C 1 -C 6 alkyl, C 1 -C 6 alkoxy, halogen or OR 3 ; or R 1 and R 2 , taken together, are linear C 1 -C 6 alkylene which is unsubstituted or substituted by C 1 -C 6 alkyl, C 1 -C 6 alkoxy, halogen, C 3 -C 8 cycloalkyl, phenyl, benzyl, C 1 -C 4 alkylphenyl, C 1 -C 4 alkoxyphenyl, halophenyl, C 1 -C 4 alkylbenzyl, C 1 -C 4 alkoxybenzyl or halobenzyl, 5-, 6-, or 7-membered heterocyclic structure containing two oxygen elements, R 3 preferably represents hydrogen, linear or branched C 1 -C 16 alkyl or C 2 -C 18 alkoxyalkyl; or are C 3 -C 8 cycloalkyl, phenyl or benzyl which are unsubstituted or substituted by C 1 -C 6 alkyl; and
X is S, N or O.

15. The capacitor of claim 14 wherein X is S.

16. The capacitor of claim 14 wherein R 1 and R 2 are taken together to represent —O—(CHR 4 ) n —O— wherein:
n is an integer from 1 to 5;
R 4 is independently selected from hydrogen; a linear or branched C 1 to C 18 alkyl radical C 5 to C 12 cycloalkyl radical, C 6 to C 14 aryl radical C 7 to C 18 aralkyl radical or C 1 to C 4 hydroxyalkyl radical optionally substituted with a functional group selected from carboxylic acid, hydroxyl, amine, substituted amines, alkene, acrylate, thiol, alkyne, azide, sulfate, sulfonate, sufonic acid, imide, amide, epoxy, anhydride, silane, and phosphate; hydroxyl radical; or R 4 is selected from —(CHR 5 ) a —R 16 ; —O(CHR 5 ) a R 16 ; —CH 2 O(CHR 5 ) a R 16 ; —CH 2 O(CH 2 CHR 5 O) a R 16 ; or
R 4 is a functional group selected from the group consisting of hydroxyl, carboxyl, amine, epoxy, amide, imide, anhydride, carboxylic acid, hydroxymethyl, alkene, thiol, alkyne, azide, sulfate, sulfonic acid, benzene sulfonic acid, SO 3 M, anhydride, silane and phosphate;
R 5 is H or alkyl chain of 1 to 5 carbons optionally

Assignees

• Kemet Electronics Corp

Inventors

• Bunha Ajaykumar
• Chacko Antony P
• Shi Yaru
• Chen Qingping
• Lessner Philip M

Classifications

• H01G9/028

  Organic semiconducting electrolytes, e.g. TCNQ · CPC title

• H01M4/136

  Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title

• H01G9/15

  Solid electrolytic capacitors (H01G11/00 takes precedence) · CPC title

• H01G9/0036

  Formation of the solid electrolyte layer · CPC title

• H01G9/0425

  specially adapted for cathode · CPC title