LITHIUM BORATES AND PHOSPHATES COATINGS

• US 20170294649A1
• 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, ARONOV, Daniel
• Granted Patent: US 10,355,271 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 4/134 Electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/1395 of 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 4/624 Electric conductive fillers
• 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 comprises at least one of a boron oxide, a phosphorus oxide, a borate, a phosphate and salts thereof.

2. The anode of claim 1, wherein the at least one coating comprises crystals of borate salt and/or phosphate.

3. The anode of claim 1, wherein the at least one coating comprises a layer of B₂O₃ which replace a native oxide on the surface of the anode active material particles.

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

6. The anode of claim 1, wherein the anode active material particles are lithiated and the at least one coating further comprises a hydrophobic conductive polymer which has conjugated aromatic groups and is ionic conductive.

7. 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.

8. 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.

9. The anode of claim 1, further comprising at least one conductive additive and binder, and consolidated and in contact with a current collector.

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

11. A method of making an anode for a lithium-ion energy storage device, comprising milling anode active material particles selected from Si, Ge, Sn, Al mixtures thereof, and alloys thereof in a non-oxidizing atmosphere with at least one boron oxide compound or phosphorus oxide compound to form milled particles having a coating on the particles selected from the group consisting of a boron oxide, a phosphorus oxide, a borate and a phosphate, having a thickness in a range of 2 nm to 200 nm

12. The method of claim 11, wherein said at least one boron oxide compound or phosphorous oxide compound contains lithium.

13. The method of claim 12, further comprising bonding a hydrophobic polymer layer to said anode active material particles by ball milling a hydrophobic polymer with the anode active material particles.

14. The method of claim 11, further comprising mixing the milled particles with conductive filler and binder to prepare an anode for a lithium-ion energy storage device.

15. The method of claim 11, further comprising coating the anode active material particles with a layer of lithiated conductive polymer.

16. The method of claim 11, further comprising coating the anode active material particles with a layer of carbon or transition metal oxide having a thickness of 1-10 nm.