Low freezing electrolyte for an electrolytic capacitor
View Patent ↗An electrolytic capacitor comprising an anode, cathode and an electrolyte. The electrolyte comprises: about 35-60%, by weight water; about 10-55%, by weight organic solvent; about 0.05 to 10%, by weight, sulphuric acid; about 0.05 to 10%, by weight, boric acid; and about 0.05 to 10%, by weight, phosphorus oxy acid.
1. An electrolytic capacitor comprising an
anode, cathode and an electrolyte comprising:
about 35-60%, by weight water;
about 10-55%, by weight organic solvent excluding ethylene glycol, formamide, dimethyl formamide and γ-butyrolactone;
about 0.05 to 30%, by weight, at least one acid selected from sulphuric, boric acid and phosphorus oxy acid.
2. The electrolytic capacitor of claim 1 wherein said acid comprises sulphuric acid and at least one acid selected from boric acid and phosphorus oxy acid.
3. The electrolytic capacitor of claim 2 wherein said acid comprises sulphuric acid, boric acid and phosphorus oxy acid.
4. The electrolytic capacitor of claim 3 wherein said electrolytic solution comprises: about 0.05 to 10%, by weight, sulphuric acid;
about 0.05 to 10%, by weight, boric acid; and about 0.05 to 10%, by weight, phosphorus oxy acid.
5. The electrolytic capacitor of claim 1 wherein said solvent is selected from a group consisting of glycerol, 1,3-propane diol; 2-methyl-1,3-propane diol; propylene glycol; polyethylene glycol monomethyl ether; N-alkyl-2-pyrrolidone and diethylene glycol.
6. The electrolytic capacitor of claim 5 wherein said solvent is glycerol.
7. The electrolytic capacitor of claim 5 wherein said solvent is 1,3-propane diol.
8. The electrolytic capacitor of claim 5 wherein said solvent is 2-methyl-1,3-propane diol.
9. The electrolytic capacitor of claim 5 wherein said solvent is propylene glycol.
10. The electrolytic capacitor of claim 5 wherein said solvent is polyethylene glycol monomethyl ether.
11. The electrolytic capacitor of claim 1 comprising about 35-55%, by weight, organic solvent.
12. The electrolytic capacitor of claim 1 comprising about 40-60%, by weight, water.
13. The electrolytic capacitor of claim 1 wherein said phosphorus oxy acid is orthophosphoric acid.
14. The electrolytic capacitor of claim 1 wherein said phosphorus oxy acid is phosphorous acid.
15. The electrolytic capacitor of claim 1 wherein said electrolyte has a pH below about 7.
16. The electrolytic capacitor of claim 15 wherein said electrolyte has a pH below about 5.
17. The electrolytic capacitor of claim 16 wherein said electrolyte has a pH below about 4.
18. The electrolytic capacitor of claim 1 wherein said anode is tantalum.
19. The electrolytic capacitor of claim 1 wherein said cathode is a conductive metal provided with a semiconductive or pseudoconductive coating.
20. The electrolytic capacitor of claim 19 wherein said cathode is at least one element chosen from a group consisting of oxide, nitride, carbide or carbon nitride of a metal.
21. The electrolytic capacitor of claim 20 wherein said cathode comprises a metal selected from a group consisting of tantalum, titanium, iridium, platinum, palladium, gold, silver, molybdenum, ruthenium, tungsten, zirconium, hafnium, rhodium, vanadium, osmium and niobium.
22. The electrolytic capacitor of claim 21 wherein when said acid comprises sulphuric acid said cathode is a metal selected from a group consisting of tantalum, iridium, platinum, palladium, gold, silver, ruthenium, tungsten, rhodium, vanadium and osmium.
23. The electrolytic capacitor of claim 19 wherein said cathode comprises a porous ruthenium oxide film provided on a tantalum substrate.
24. The electrolytic capacitor of claim 1 wherein said electrolyte has a freezing point below about −30° C.
25. An electrolyte for activating a capacitor comprising:
about 35-60%, by weight water;
about 10-55%, by weight organic solvent excluding ethylene glycol, formamide, dimethyl formamide and γ-butyrolactone;
about 0.05 to 30%, by weight, at least one acid selected from sulphuric, boric acid and phosphorus oxy acid.
26. The electrolyte of claim 25 wherein said acid comprises sulphuric acid and at least one acid selected from boric acid and phosphorus oxy acid.
27. The electrolyte of claim 26 wherein said acid comprises sulphuric acid, boric acid and phosphorus oxy acid.
28. The electrolyte of claim 27 wherein said electrolytic solution comprises:
about 0.05 to 10%, by weight, sulphuric acid;
about 0.05 to 10%, by weight, boric acid; and
about 0.05 to 10%, by weight, phosphorus oxy acid.
29. The electrolyte of claim 25 wherein said solvent is selected from a group consisting of glycerol, 1,3-propane diol; 2-methyl-1,3-propane diol; propylene glycol; polyethylene glycol monomethyl ether; N-alkyl-2-pyrrolidone and diethylene glycol.
30. The electrolyte of claim 29 wherein said solvent is glycerol.
31. The electrolyte of claim 25 wherein said solvent is 1,3-propane diol.
32. The electrolyte of claim 31 wherein said solvent is 2-methyl-1,3-propane diol.
33. The electrolyte of claim 25 wherein said solvent is propylene glycol.
34. The electrolyte of claim 25 wherein said polymer is polyethylene glycol monomethyl ether.
35. The electrolyte of claim 25 wherein said phosphorus oxy acid is orthophosphoric acid.
36. The electrolyte of claim 25 wherein said phosphorus oxy acid is phosphorous acid.
37. The electrolyte of claim 25 wherein said electrolyte has a pH of less than about 7.
38. The electrolyte of claim 37 wherein said electrolyte has a pH of less than about 5.
39. The electrolyte of claim 38 wherein said electrolyte has a pH of less than about 4.
40. The electrolyte of claim 25 wherein said electrolyte has a freezing point below about −30° C.
41. A capacitor comprising the electrolyte of claim 25 .
42. An electrolytic capacitor comprising an anode, cathode and an electrolyte comprising:
about 35-60%, by weight water;
about 10-55%, by weight organic solvent excluding ethylene glycol, formamide, dimethyl formamide and γ-butyrolactone;
about 0.05 to 30%, by weight, a mixture of ammonium acetate, boric acid, phosphorus oxy acid and acetic acid.
43. The electrolytic capacitor of claim 41 wherein said electrolytic solution comprises: about 0.05 to 10%, by weight, ammonium acetate;
about 0.05 to 10%, by weight, boric acid;
about 0.05 to 10%, by weight, phosphorus oxy acid.
44. The electrolytic capacitor of claim 41 wherein said solvent is selected from a group consisting of glycerol, 1,3-propane diol; 2-methyl-1,3-propane diol; propylene glycol; polyethylene glycol monomethyl ether; N-alkyl-2-pyrrolidone and diethylene glycol.
45. An electrolytic capacitor comprising an anode, cathode and an electrolyte comprising:
about 35-60%, by weight water;
about 10-55%, by weight organic solvent selected from a group consisting of glycerol, 1,3-propane diol; 2-methyl-1,3-propane diol; propylene glycol; polyethylene glycol monomethyl ether; N-alkyl-2-pyrrolidone and diethylene glycol;
about 0.05 to 30%, by weight, a mixture of ammonium acetate and acetic acid.