Controlled crystallite size electrode

• US 6,110,620 A
• Filed: 09/30/1997
• Issued: 08/29/2000
• Est. Priority Date: 09/30/1997
• Status: Expired due to Fees

• Current Assignee: Congress Financial Corporation (Wells Fargo & Company)
• Original Assignee: Eveready Battery Company Incorporated (Energizer Holdings, Inc.)
• Inventors: Young, Jon R., Singh, Deepika B.
• Primary Examiner(s): Nuzzolillo, Maria
• Assistant Examiner(s): Martin, Angela J.
• Application Number:
  US08/941,666
• Time in Patent Office: 1,064 Days
• Field of Search: 429/223, 429/218.1, 429/235, 423/592, 205/705, 205/723
• US Class Current: 429/223
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H01M 4/26 Processes of manufacture
• CPC Class Codes: H01M 4/28 Precipitating active material on the carrier
• CPC Class Codes: H01M 4/52 of nickel, cobalt or iron
• CPC Class Codes: H01M 4/621 Binders
• CPC Class Codes: H01M 4/624 Electric conductive fillers
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

This invention relates to methods for forming nickel hydroxide battery electrodes comprising nickel hydroxide particles which have crystallite sizes falling within the range of about 60 Å to about 160 Å.

Claims

1. A sintered electrode comprising Ni(OH)₂ particles in which all crystallites thereof fall within a size range of about 60 Å

to about 160 Å

.

2. The electrode of claim 1 wherein said crystallites have an average size of about 80 Å

to about 130 Å

.

3. The electrode of claim 2 wherein said crystallites have an average size of about 90 Å

to about 120 Å

.

4. The electrode of claim 3 wherein said crystallites have an average size of about 100 Å

to about 110 Å

.

27. A cell comprising the electrode of claim 1.

28. A cell comprising the electrode of claim 4.

5. A method for producing a controlled crystallite size nickel hydroxide sintered electrode, having Ni(OH)₂ particles in which all crystallites thereof fall within a 60-160 Å

size range, comprising the steps of;

providing a conductive metal sintered plaque substrate; and

putting said substrate through at least one impregnation-cleaning series, said impregnation-cleaning series comprising the substeps of;

a) impregnating said substrate with nickel hydroxide by putting said substrate through one or more impregnation cycles to form an impregnated substrate; and

b) electrochemically cleaning said impregnated substrate at least once, said substep of electrochemically cleaning said impregnated substrate comprising the sub-substeps of;

i) immersing said impregnated substrate into a solution of at least one caustic base, and

ii) applying a charge to said impregnated substrate, said charge being equivalent to at least about 120% of single-electron capacity, but less than that producing crystallites less than about 60 Å

in size.

6. The method according to claim 5 wherein said method further comprises repeating said substep of impregnating said substrate, after said step of putting said substrate through at least one impregnation-cleaning series.

7. The method according to claim 5 wherein a total of two impregnation-cleaning series are performed, said substep of impregnating said substrate comprising two to five impregnation cycles.

8. The method according to claim 7 wherein said substep of impregnating said substrate comprises 3 impregnation cycles.

9. The method according to claim 5 further comprising a step comprising incorporating said impregnated substrate as a positive electrode into an electrochemical cell, after said step of putting said substrate through at least one impregnation-cleaning series.

10. The method according to claim 5 wherein said charge is equivalent to at least about 135% of the single electron capacity of said impregnated substrate.

11. The method according to claim 9 wherein said charge is equivalent to at least about 140% of the single electron capacity of said impregnated substrate.

12. The method according to claim 9 wherein said charge is equivalent to at least about 150% of the single electron capacity of said impregnated substrate.

13. The method according to claim 5 wherein said caustic base is selected from the group consisting of metal hydroxides and mixtures thereof.

14. The method according to claim 13 wherein said caustic base is selected from the group consisting of alkali metal hydroxides, alkaline earth metal hydroxides, and mixtures thereof.

15. The method according to claim 14 wherein said caustic base is selected from the group consisting of NaOH, KOH, LiOH, and mixtures thereof.

16. The method according to claim 5 wherein said impregnation cycle comprises:

a first sub-substep comprising loading said substrate with at least one nickel compound to form a loaded substrate; and

a second sub-substep comprising converting said nickel compound to nickel hydroxide by immersing said loaded substrate into a solution of at least one caustic base.

17. The method according to claim 16 wherein said loading comprises immersing said substrate in an acidic solution comprising at least one nickel compound.

18. The method according to claim 17 wherein said at least one nickel compound is nickel nitrate.

19. The method according to claim 17 wherein said solution further comprises at least one other metal compound.

20. The method according to claim 19 wherein said at least one other metal compound is selected from the group consisting of cadmium compounds, calcium compounds, cobalt compounds, copper compounds, bismuth compounds, indium compounds, magnesium compounds, manganese compounds, vanadium compounds, yttrium compounds, zinc compounds, non-Ni(OH)₂ nickel compounds, and mixtures thereof.

21. The method according to claim 19 wherein said at least one other metal is selected from the group consisting of metal nitrates and mixtures thereof.

22. The electrode produced according to the method of claim 5.

23. The electrode produced according to the method of claim 7.

24. The electrode produced according to the method of claim 12.

25. The electrode produced according to the method of claim 16.

26. The electrode produced according to the method of claim 19.

29. The cell produced according to the method of claim 9.

30. A cell comprising the electrode of claim 22.

31. A cell comprising the electrode of claim 23.

32. A cell comprising the electrode of claim 24.

33. A cell comprising the electrode of claim 25.

34. A cell comprising the electrode of claim 26.