POLYMER COATINGS AND ANODE MATERIAL PRE-LITHIATION

• US 20170294648A1
• Filed: 04/06/2017
• Published: 10/12/2017
• Est. Priority Date: 04/07/2016
• Status: Active Grant

• Current Assignee: StoreDot Ltd.
• Original Assignee: StoreDot Ltd.
• Inventors: BURSHTAIN, Doron, KEDEM, Nir, SELLA, Eran, ARONOV, Daniel
• Granted Patent: US 10,290,864 B2
• Time in Patent Office: Days
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 2004/027 Negative electrodes
• CPC Class Codes: H01M 4/0404 by coating on electrode collectors
• CPC Class Codes: H01M 4/134 Electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/366 as layered products
• CPC Class Codes: H01M 4/386 Silicon or alloys based on silicon
• CPC Class Codes: H01M 4/387 Tin or alloys based on tin
• CPC Class Codes: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: H01M 4/608 containing heterocyclic rings
• CPC Class Codes: H01M 4/624 Electric conductive fillers
• CPC Class Codes: H01M 4/625 Carbon or graphite
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Improved anodes and cells are provided, which enable fast charging rates with enhanced safety due to much reduced probability of metallization of lithium on the anode, preventing dendrite growth and related risks of fire or explosion. Anodes and/or electrolytes have buffering zones for partly reducing and gradually introducing lithium ions into the anode for lithiation, to prevent lithium ion accumulation at the anode electrolyte interface and consequent metallization and dendrite growth. Various anode active materials and combinations, modifications through nanoparticles and a range of coatings which implement the improved anodes are provided.

Claims

1. An anode comprising anode active material particles which are coated by at least one coating, wherein the anode active material particles comprise at least one of Si, Ge, Sn and Al and the at least one coating is at least partly polymeric.

2. The anode of claim 1, wherein the at least one coating comprises a conductive polymer.

3. The anode of claim 2, wherein the conductive polymer is lithiated.

4. The anode of claim 3, wherein the lithiated conductive polymer comprises a buffering zone configured to receive lithium ions from an interface of the anode active material particles with an electrolyte, partially reduce the received lithium ions, and enable the partially reduced lithium ions to move into an inner zone of the anode active material particles for lithiation therein.

5. The anode of claim 2, wherein the conductive polymer comprises polyaniline which is polymerized in situ in the anode.

6. The anode of claim 1, wherein the anode active material particles are lithiated and the at least one coating comprises a hydrophobic conductive polymer.

7. The anode of claim 6, wherein the hydrophobic conductive polymer comprises conjugated aromatic groups and is ionic conductive.

8. The anode of claim 6, wherein the hydrophobic conductive polymer comprises polypyrrole and/or polyaniline.

9. The anode of claim 1, wherein the at least one coating comprises at least one lithiated polymer.

10. The anode of claim 9, wherein the at least one lithiated polymer comprises at least one of lithium polyphosphate, lithium poly(acrylic acid), lithium carboxyl methyl cellulose and lithium alginate.

11. The anode of claim 1, wherein the at least one coating further comprises a layer of at least one of:

an amorphous carbon, graphene, graphite, a transition metal and a lithiated polymer.

12. The anode of claim 1, wherein the anode active material particles are 20-500 nm in diameter and the at least one coating is 2-200 nm thick.

13. A lithium ion cell comprising the anode of claim 1.

14. A method of manufacturing a lithium-ion energy storage device, comprising:

providing lithium-doped anode active material comprising metalloid particles selected from the group consisting of Si, Ge, Sn, Al, Pb, Zn, Cd, and alloys thereof;

bonding a hydrophobic polymer layer to said lithium-doped anode active material to form coated anode active material particles;

forming a slurry of the coated anode active material particles with additional anode materials in a medium containing water; and

drying the slurry and contacting the dried slurry with a current collector to form an anode.

15. The method of claim 14, wherein said bonding the hydrophobic polymer layer to said lithium-doped anode active material is carried out by ball milling a hydrophobic polymer with the lithium-doped anode active material particles.

16. The method of claim 14, wherein said bonding is carried out chemically in a suspension.

17. A method of making a lithium-ion energy storage device, comprising making anode active material by chemically bonding a lithium-containing polymer to a surface of anode active material particles selected from the group consisting of Si, Ge, Sn, Pb, Al, mixtures thereof and alloys thereof, having a particle size of 20 to 500 nm to form coated nanoparticles;

and mixing the coated anode active material particles with conductive filler and binder to form an anode, wherein said lithium containing polymer is configured to provide support to solid electrolyte interphase formed at a surface of the anode.

18. The method according to claim 17, wherein the lithium-containing polymer is selected from the group consisting of lithium poly phosphate, lithium poly acrylic acid, lithium carboxyl methyl cellulose, and lithium alginate.

19. The method according to claim 17, further comprising coating the coated anode active material particles with an additional layer of carbon or transition metal oxide, said additional layer having a thickness of 1-10 nm.