TIN SILICON ANODE ACTIVE MATERIAL

• US 20170294643A1
• 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, Remizov, Sergey, Jacob, David, Shadmi, Nitzan, Farran, Hani, Shapiro, Leora, Goldbart, Ohad, Brudnik, Boris, Ophir, Carmit, Aronov, Daniel
• Granted Patent: US 10,367,191 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 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 4/621 Binders
• 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 comprise tin.

2. The anode of claim 1, wherein the anode active material particles comprise 5-80% tin.

3. The anode of claim 2, wherein the anode active material particles further comprise at least one of germanium, silicon, boron, alloys and mixtures thereof.

4. The anode of claim 2, wherein the anode active material particles further comprise nanoparticles attached thereto, wherein the nanoparticles are at least one order of magnitude smaller than the anode active material particles.

5. The anode of claim 4, wherein the anode active material particles are 100-500 nm in diameter and have nanoparticles attached thereto which are 10-50 nm in diameter.

6. The anode of claim 4, wherein the nanoparticles are embedded in the anode active material particles.

7. The anode of claim 4, wherein the nanoparticles are made of boron carbide and/or tungsten carbide.

8. The anode of claim 7, wherein the nanoparticles are B₄C nanoparticles, which are attached at between 2-25 weight % of the anode active material particles.

9. The anode of claim 4, wherein the anode active material particles further comprise a 1-10 nm thick surface layer of any of:

an amorphous carbon, graphene and graphite.

10. The anode of claim 4, wherein the anode active material particles further comprise a 1-10 nm thick surface layer of a transition metal.

11. The anode of claim 4, wherein the anode active material particles further comprise a 1-10 nm thick surface layer of a lithium polymer.

12. The anode of claim 11, wherein the surface layer 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.

13. The anode of claim 1, wherein the anode active material particles further comprise a coating by a polymer which is conductive and/or lithiated.

14. The anode of claim 13, wherein the anode active material particles are 20-500 nm in diameter and the coating is 2-200 nm thick.

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

16. A method of making a Li-ion energy storage device, comprising:

combining metalloid particles having a particle size of 100-500 nm and comprising a metalloid selected from the group consisting of Sn, Pb, Ge, Si, and alloys thereof, with B₄C nanoparticles having a particle size of 10-50 nm, to form an anode active material.

17. The method of claim 16, wherein said combining is performed by milling the metalloid particles and B₄C nanoparticles together to embed the B₄C nanoparticles in a surface of the metalloid particles.

18. A method comprising preparing an anode for a lithium ion cell from tin active material particles by forming a slurry with the tin active material particles, a solvent, and at least one additive selected from the group consisting of conductive particles, binder and plasticizer;

and removing solvent and consolidating the slurry to form an anode.

19. The method of claim 18, wherein the tin active material particles comprise 5-80% tin, further comprise at least one of Si, Ge, B and W, and have a particle size of 100-500 nm.

20. The method of claim 19, further comprising attaching B₄C and/or WC nanoparticles to the tin active material particles, wherein the B₄C and/or WC nanoparticles have a particle size of 10-50 nm.