Capacitor anode formed of metallic columns on a substrate
View Patent ↗Capacitor anodes that include metallic columns formed on a substrate so as to form a porous microstructure and methods of making the anodes are described. The metallic columns can be distinct from one another and project outward from the substrate. Also described is the formation of the metallic columns on the substrate by vapor deposition, including glancing angle deposition (GLAD), and by etching a portion of a metal layer. High capacitance capacitors made from the capacitor anodes are also described.
1. A capacitor anode comprising a substrate having metallic columns thereon to form a porous microstructure, wherein said metallic columns have a substantially helical cross-section.
2. The capacitor anode of claim 1 , wherein said metallic columns are distinct from one another, and wherein said metallic columns project outward from said substrate.
3. The capacitor anode of claim 1 , wherein said metallic columns comprise an ordered orientation.
4. The capacitor anode of claim 1 , wherein said metallic columns comprise a random orientation.
5. The capacitor anode of claim 1 , wherein said metallic columns have a width of at least about 0.001 microns.
6. The capacitor anode of claim 1 , wherein said metallic columns have a width of from about 0.05 to about 0.5 microns.
7. The capacitor anode of claim 1 , wherein said metallic columns have a height of at least about 0.1 microns.
8. The capacitor anode of claim 1 , wherein said metallic columns have a height of from about 0.1 to about 2000 microns.
9. The capacitor anode of claim 1 , wherein said metallic columns have a height of from about 0.1 to about 2000 microns, and a width of from about 0.05 to about 0.5 microns.
10. The capacitor anode of claim 1 , wherein said metallic columns have an aspect ratio of at-least 2 to 1.
11. The capacitor anode of claim 1 , wherein said metallic columns have an angular orientation relative to said substrate.
12. The capacitor anode of claim 1 , wherein said substrate is a valve metal foil.
13. The capacitor anode of claim 1 , wherein said substrate comprises a foil.
14. The capacitor anode of claim 1 , wherein said substrate comprises a tantalum foil.
15. The capacitor anode of claim 1 , wherein said metallic columns are solid.
16. The capacitor anode of claim 1 , wherein said metallic columns are hollow.
17. The capacitor anode of claim 1 , wherein said metallic columns comprise a valve metal.
18. The capacitor anode of claim 1 , wherein said metallic columns comprise a valve metal, and wherein said substrate comprises valve metal.
19. The capacitor anode of claim 1 , wherein said porous microstructure has a BET surface area of at least 0.1 m 2 /g.
20. The capacitor anode of claim 1 , wherein said porous microstructure has a BET surface area of from about 1 to about 20 m 2 /g.
21. The capacitor anode of claim 1 , wherein said anode has a capacitance of at least 12,500 CV/g.
22. The capacitor anode of claim 1 , wherein said anode has a capacitance of from about 12,500 to about 2,000,000 CV/g.
23. A capacitor comprising the anode of claim 1 .
24. The capacitor of claim 23 , further comprising:
a dielectric layer on a surface of said anode;
a manganese dioxide layer adjacent to said dielectric layer;
a graphite layer adjacent to said manganese dioxide layer;
an exterior shell in electrical contact with said graphite layer; and
conductive contacts fixed to said exterior shell.
25. A method of making the capacitor anode of claim 1 , comprising:
forming said metallic columns on a said substrate; and
forming a dielectric layer over said metallic columns and said substrate to form a porous microstructure.
26. The method of claim 25 , farther comprising forming bases on said substrate at predetermined locations, wherein said metallic columns are formed on said bases.
27. The method of claim 25 , wherein said metallic columns are distinct from one another, and wherein said metallic columns project outward from said substrate.
28. The method of claim 25 , wherein said metallic columns are formed as an ordered orientation.
29. The method of claim 25 , wherein said metallic columns are formed as a random orientation.
30. The method of claim 25 , wherein said metallic columns are formed by depositing vaporized metal on said substrate.
31. The method of claim 25 , wherein said metallic columns comprise a valve metal.
32. The method of claim 25 , wherein said metallic columns comprise niobium or tantalum.
33. The method of claim 25 , wherein said metallic columns are formed on said substrate by glancing angle deposition.
34. The method of claim 25 , wherein said substrate is a valve metal foil.
35. The method of claim 25 , wherein said substrate comprises a foil.
36. The method of claim 25 , wherein said substrate comprises a tantalum foil.
37. The method of claim 25 , wherein said substrate comprises a mosaic.
38. The method of claim 25 , further comprising dividing said substrate into a plurality of substrates.
39. The method of claim 25 , wherein said metallic columns are formed to a width of up to about 10 microns.
40. The method of claim 25 , wherein said metallic columns are formed to a width of from about 0.001 to about 10 microns.
41. The method of claim 25 , wherein said metallic columns are formed to a height up to about 1000 microns.
42. The method of claim 25 , wherein said metallic columns are formed on said substrate by etching a metallic layer optionally through a mask.
43. The method of claim 25 , wherein said metallic columns are formed to a height of from about 1 to about 500 microns.
44. The method of claim 25 , wherein said metallic columns have an aspect ratio of at least 2 to 1.
45. The method of claim 25 , wherein said metallic columns are formed to a height of from about 1 to about 1000 microns, and a width of from about 0.01 to about 10 microns.
46. The method of claim 25 , wherein said metallic columns have an angular orientation relative to said substrate.
47. The method of claim 25 , wherein said porous microstructure has a BET surface area of at least 0.1 m 2 /g.
48. The method of claim 25 , wherein said porous microstructure has a BET surface area of from about 0.1 to about 20 m 2 /g.
49. The method of claim 25 , wherein said anode has a capacitance of at least 12,500 CV/g.
50. The method of claim 25 , wherein said anode has a capacitance of from about 12,500 to about 2,000,000 CV/g.
51. The method of claim 25 , wherein said metallic columns are formed on said substrate by glancing angle deposition.
52. The method of claim 25 , wherein said metallic columns are formed on said substrate by physical vapor deposition or chemical vapor deposition.
53. The method of claim 25 , wherein said metallic columns are formed on said substrate by sputtering.