Densified battery electrodes and methods thereof

Patent metadata

Field	Value
Publication number	US-12199269-B2
Application number	US-202318541284-A
Country	US
Kind code	B2
Filing date	Dec 15, 2023
Priority date	May 23, 2019
Publication date	Jan 14, 2025
Grant date	Jan 14, 2025

Abstract

In an aspect, a Li-ion cell may comprise a densified electrode exhibiting an areal capacity loading of more than about 4 mAh/cm 2 . For example, the densified electrode may a first electrode part arranged on a current collector and a second electrode part on top of the first electrode part, the second electrode part of the at least one densified electrode having a higher porosity than the first electrode part of the at least one densified electrode. In some designs, the densified electrode may be fabricated by densifying electrode layers via a pressure roller while maintaining a contacting part of the pressure roller at a temperature that is less than a temperature of the second electrode part. In some designs, the applied pressure is a time-varying (e.g., frequency modulated) pressure. In some designs, a drying time for a slurry to produce the densified electrode may range from around 1-120 seconds.

First claim

The invention claimed is:

1. A method of electrode manufacture, comprising:
depositing a pre-calendering electrode layer onto current collector foils to produce a pre-calendering electrode, the pre-calendering electrode layer comprising an active material with an areal capacity loading of at least about 4 mAh/cm 2 , a binder, and conductive additives; and
calendering the pre-calendering electrode via one or more pressure rollers that comprise one or more respective surfaces that exhibit an average temperature T 2 to produce a calendered electrode with a densified electrode layer,
wherein:
the pre-calendering electrode exhibits an average temperature T 1 prior to the calendaring,
the pre-calendering electrode layer exhibits a first porosity and a first density,
the densified electrode layer exhibits a second porosity that is less than the first porosity,
the densified electrode layer exhibits a second density that is greater than the first density, and
the average temperature T 2 ranges from around 120° C. lower than T 1 to around 20° C. higher than T 1 .

2. The method of claim 1 , further comprising:
after the depositing and before the calendering, pre-heating the pre-calendering electrode to the average temperature T 1 .

3. The method of claim 1 , wherein the average temperature T 2 is less than the average temperature T 1 .

4. The method of claim 1 , wherein at least part of the one or more respective surfaces of the one or more pressure rollers contacts a surface of the pre-calendering electrode during the calendering.

5. The method of claim 1 , wherein a temperature difference between the average temperature T 1 and the average temperature T 2 ranges from about 20° C. to about 40° C.

6. The method of claim 1 , wherein a temperature difference between the average temperature T 1 and the average temperature T 2 ranges from about 40° C. to about 60° C.

7. The method of claim 1 , wherein the conductive additives comprise: (i) carbon nanotubes, (ii) graphene or exfoliated graphite, (iii) carbon black, or (iv) any combination thereof.

8. The method of claim 1 , wherein the conductive additives comprise: (i) graphene, (ii) graphene oxide, (iii) exfoliated graphite, (iv) carbide flakes, or (v) any combination thereof.

9. The method of claim 1 , wherein the densified electrode layer comprises composite particles that comprise the active material.

10. The method of claim 9 , wherein the conductive additives exhibit a first surface charge that is opposite to a second surface charge of the composite particles.

11. The method of claim 9 , wherein the active material comprises Si.

12. The method of claim 11 , wherein the composite particles comprise the Si and C.

13. The method of claim 10 , wherein the composite particles are nanocomposite particles.

14. The method of claim 1 , wherein a weight fraction of the conductive additives in the densified electrode layer ranges from about 0.02 wt. % to about 10 wt. %.

15. The method of claim 1 , wherein the depositing deposits the pre-calendering electrode layer as a dry electrode coating.

16. The method of claim 1 , wherein the depositing deposits the pre-calendering electrode layer via a slurry coating.

17. The method of claim 16 , wherein the slurry coating is an aqueous slurry.

18. The method of claim 1 , wherein the areal capacity loading ranges from about 4 mAh/cm 2 to about 6 mAh/cm 2 .

19. The method of claim 1 , wherein the areal capacity loading ranges from about 6 mAh/cm 2 to about 9 mAh/cm 2 .

20. The method of claim 1 , wherein the second porosity comprises between about 10 vol. % to about 20 vol. % of the densified electrode layer.

21. The method of claim 1 , wherein the second porosity comprises between about 20 vol. % to about 30 vol. % of the densified electrode layer.

22. The method of claim 1 , wherein a minimum separation distance between the one or more respective surfaces of the one or more pressure rollers and a surface of the pre-calendering electrode layer is modulated during the calendering.

23. The method of claim 22 , wherein the modulation is periodic.

24. The method of claim 22 , wherein the modulation is aperiodic.

25. The method of claim 22 , wherein an amplitude of the modulation ranges from about 0.5% to about 20% of a thickness of the pre-calendering electrode.

26. The method of claim 22 ,
wherein the pre-calendering electrode layer comprises composite particles that comprise the active material, and wherein an amplitude of the modulation ranges from about 50% to about 2,000% of an average diameter of the composite particles.

27. The method of claim 22 , wherein a frequency of the modulation is in a range from about 0.1 Hz to about 10 MHz.

28. The method of claim 27 , wherein a frequency of the modulation is in a range from about 0.1 Hz to about 20 Hz.

29. The method of claim 27 , wherein a frequency of the modulation is in a range from about 22 kHz to about 10 MHz.

30. The method of claim 22 , wherein the modulation is based on a first function associated with a first frequency and a first amplitude and a second function associated with a second frequency and a second amplitude.

31. The method of claim 1 , wherein the densified electrode layer further comprises ceramic nanofibers.

32. The method of claim 31 , wherein the ceramic nanofibers comprise two or more of: aluminum (Al), oxygen (O), magnesium (Mg), lithium (Li), sodium (Na), and silicon (Si).

33. The method of claim 31 , wherein at least one of the ceramic nanofibers is porous.

34. The method of claim 1 , wherein the calendared electrode is configured for use as a Li-ion battery anode.

Assignees

• Sila Nanotechnologies Inc

Inventors

• Yushin Gleb
• Berdichevsky Gene

Classifications

• H01M4/625

  Carbon or graphite · CPC title

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/0435 Primary

  Rolling or calendering · CPC title

• H01M4/0404

  by coating on electrode collectors · CPC title