Fabrication of highly textured lithium cobalt oxide films by rapid thermal annealing

• US 6,344,366 B1
• Filed: 09/15/1999
• Issued: 02/05/2002
• Est. Priority Date: 09/15/1999
• Status: Expired due to Term

• Current Assignee: UT-Battelle LLC
• Original Assignee: Lockheed Martin Energy Research Corporation (Martin Marietta Corporation)
• Inventors: Bates, John B.
• Primary Examiner(s): Bowers, Charles
• Assistant Examiner(s): Thompson, Craig
• Application Number:
  US09/396,997
• Time in Patent Office: 874 Days
• Field of Search: 438/19, 438/795, 438/797, 438/660, 438/663, 438/664, 438/800, 427/255.11, 427/225.25, 505/1, 219/483, 429/304-322
• US Class Current: 438/19
• CPC Class Codes: C01G 51/42 containing alkali metals, e.g. LiCoO2
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2002/74 by peak-intensities or a ratio thereof only
• CPC Class Codes: H01M 4/04 Processes of manufacture in general
• CPC Class Codes: H01M 4/0404 by coating on electrode collectors
• CPC Class Codes: H01M 4/0426 Sputtering
• CPC Class Codes: H01M 4/0471 involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
• CPC Class Codes: H01M 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/485 of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy H01M4/505, H01M4/525 take precedence
• CPC Class Codes: H01M 4/52 of nickel, cobalt or iron
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Systems and methods are described for fabrication of highly textured lithium cobalt oxide films by rapid thermal annealing. A method of forming a lithium cobalt oxide film includes depositing a film of lithium cobalt oxide on a substrate; rapidly heating the film of lithium cobalt oxide to a target temperature; and maintaining the film of lithium cobalt oxide at the target temperature for a target annealing time of at most, approximately 60 minutes. The systems and methods provide advantages because they require less time to implement and are, therefore less costly than previous techniques.

Claims

1. A method of forming a textured LiCoO₂ film, comprising:

depositing a film of LiCoO₂ on a substrate;

rapidly heating the film of LiCoO2 to a target temperature;

maintaining the film of LiCoO2 at the target temperature for a target annealing time of at most approximately 60 minutes to form the textured LiCoO2 film; and

then

rapidly cooling the textured LiCoO2 film.

2. The method of claim 1, wherein the substrate includes at least one material selected from the group consisting of ceramics, semiconductors, and metals.

3. The method of claim 1, wherein the target temperature is greater than approximately 700°

C.

4. The method of claim 1, wherein the target temperature is at least approximately 800°

C.

5. The method of claim 1, wherein the target temperature is at least approximately 850°

C.

6. The method of claim 1, wherein the target annealing time is at most approximately 30 minutes.

7. The method of claim 1, wherein the target annealing time is approximately 12-17 minutes.

8. The method of claim 1, wherein depositing the film of LiCoO₂ includes depositing the film to a thickness of approximately 2.5-3 μ

m.

9. The method of claim 1, wherein rapidly beating the film of LiCoO₂ includes heating the film at a rate of at least approximately 50-100°

C./min.

10. The method of claim 1, wherein rapidly heating the film of LiCoO₂ includes delivering heat from a quartz lamp.

11. The method of claim 1, wherein rapidly cooling the textured LiCoO₂ film includes controlled removal of the film of LiCoO₂ from a furnace.

12. The method of claim 1, wherein rapidly cooling the textured LiCoO₂ film includes delivering a cooling jet to the textured LiCoO₂ film.

13. The method of claim 12, wherein rapidly cooling the textured LiCoO₂ film includes cooling the textured LiCoO₂ film at a rate of approximately 50-100°

C./min.

14. The method of claim 1, wherein maintaining the film of LiCoO₂ at the target temperature includes flowing O₂ over the film of LiCoO₂.

15. The method of claim 1, wherein maintaining the film of LiCoO₂ of thickness equal or greater than 1 μ

m at the target temperature for a target annealing time of at most approximately 60 minutes results in a majority of grains oriented with their (101) and (104) planes parallel to the substrate.

16. A cathode made by the method of claim 1.

17. A battery including the cathode of claim 16.

18. The method of claim 1, wherein the target annealing time is approximately 15 minutes.

19. A method of forming a film of LiCoO₂, comprising:

depositing a film of LiCoO₂ on a substrate;

rapidly heating the film of LiCoO2 to a target temperature; and

maintaining the film of LiCoO2 at the target temperature for a target annealing time of at most approximately 60 minutes,

wherein maintaining the film of LiCoO₂ of thickness equal or greater than 1 μ

m at the target temperature for a target annealing time of at most approximately 60 minutes results in a majority of grains oriented with their (101) and (104) planes parallel to the substrate.