Silicate additives for capacitor working electrolytes
View Patent ↗A capacitor working electrolyte containing water and a silicate additive is described. The silicate additive does not alter the electrolyte properties and/or cause any separation of the electrolyte composition. Instead, it stabilizes capacitor long-term performance.
1. A working electrolyte for an electrolytic capacitor, the electrolyte comprising:
a) water; and
b) a silicate compound selected from ammonium silicate and an organic compound having the chemical formula: (R 1 O—) (R 2 O—) (R 3 O—) (R 4 O—)Si, wherein R 1 , R 2 , R 3 , and R 4 may be the same or different and they are selected from the groups consisting of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and combinations thereof.
2. The electrolyte of claim 1 wherein the silicate compound is at a concentration from about 0.01%, by weight, to being saturated in the electrolyte.
3. The electrolyte of claim 1 wherein the silicate compound is at a concentration from about 0.01% to about 5%, by weight.
4. The electrolyte of claim 1 wherein the silicate compound is at a concentration less than about 0.5%, by weight.
5. The electrolyte of claim 1 not in the form of a gel upon being provided in the capacitor.
6. The electrolyte of claim 1 wherein the silicate compound is in the form of a silica sol.
7. A working electrolyte comprising, by weight:
a) about 0.1% to about 80% water;
b) 0% to about 80% of an organic solvent;
c) about 1% to about 80% of at least one ionogenic solute; and
d) a silicate compound selected from ammonium silicate and an organic compound having the chemical formula: (R 1 O—) (R 2 O—) (R 3 O—) (R 4 O—)Si, wherein R 1 , R 2 , R 3 , and R 4 may be the same or different and they are selected from the groups consisting of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and combinations thereof.
8. The electrolyte of claim 7 wherein the silicate compound is at a concentration from about 0.0.1%, by weight, to being saturated in the electrolyte.
9. The electrolyte of claim 7 wherein the silicate compound is at a concentration from about 0.01% to about 5%, by weight.
10. The electrolyte of claim 7 wherein the silicate compound is at a concentration less than about 0.5%, by weight.
11. The electrolyte of claim 7 wherein the electrolyte is used with a capacitor system powering an implantable medical device.
12. The electrolyte of claim 7 not in the form of a gel.
13. The electrolyte of claim 7 wherein the silicate compound is in the form of a silica sol.
14. A method for preparing a working electrolyte for a capacitor, comprising the steps of:
a) providing, by weight, about 0.1% to about 80% water, 0% to about 80% of an organic solvent, and about 1% to about 80% of at least one ionogenic solute; and
b) adding to the electrolyte a silicate compound selected from ammonium silicate and an organic compound having the chemical formula: (R 1 O—) (R 2 O—) (R 3 O—) (R 4 O—)Si, wherein R 1 , R 2 , R 3 , and R 4 may be the same or different and they are selected from the groups consisting of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, and combinations thereof.
15. The method of claim 14 including providing the silicate compound at a concentration from about 0.01%, by weight, to being saturated in the electrolyte.
16. The method of claim 14 including providing the silicate compound at a concentration from about 0.01% to about 5%, by weight.
17. The method of claim 14 including providing the electrolyte not being in the form of a gel.
18. The electrolyte of claim 14 including providing the silicate compound in the form of a silica sol.