Silicon particles having a specific chlorine content, as active anode material for lithium ion batteries

Patent metadata

Field	Value
Publication number	US-11936038-B2
Application number	US-201817281969-A
Country	US
Kind code	B2
Filing date	Oct 2, 2018
Priority date	Oct 2, 2018
Publication date	Mar 19, 2024
Grant date	Mar 19, 2024

Abstract

An anode active material for lithium ion batteries includes one or more unaggregated silicon particles having a mass-based chlorine content of from 5 to 200 ppm and a volume-weighted particle size distribution having diameter percentiles d50 of from 0.5 μm to 10.0 μm.

First claim

The invention claimed is:

1. An anode active material for lithium ion batteries, comprising one or more unaggregated silicon particles having a mass-based chlorine content of from 5 to 200 ppm and a volume-weighted particle size distribution having diameter percentiles d 50 of from 0.5 μm to 10.0 μm.

2. The anode active material for lithium ion batteries as claimed in claim 1 , wherein ≥50% by weight of the silicon particles have, based on the total weight of the silicon particles, a mass-based chlorine content of from 5 to 200 ppm.

3. The anode active material for lithium ion batteries as claimed in claim 1 , wherein the silicon particles are polycrystalline and have crystalline sizes of from 5 to 200 nm.

4. The anode active material for lithium ion batteries as claimed in claim 1 , wherein the silicon particles are obtainable by
1) pyrolysis of a reaction gas comprising trichlorosilane and/or dichlorosilane in a fluidized-bed reactor at deposition temperatures of from 600° C. to 1000° C. to form granular silicon and subsequent
2) milling of the granular silicon from step 1) to form the silicon particles.

5. The anode active material for lithium ion batteries as claimed in claim 4 , wherein step 1) is carried out in a fluidized-bed reactor.

6. The anode active material for lithium ion batteries as claimed in claim 4 , wherein the reaction gas does not contain any monosilane (SiH 4 ).

7. The anode active material for lithium ion batteries as claimed in claim 4 , wherein the proportion of dichlorosilane and/or trichlorosilane in the reaction gas is from 50 to 100% by weight, based on the total weight of the silanes.

8. The anode active material for lithium ion batteries as claimed in claim 4 , wherein the proportion of monochlorosilane in the reaction gas is from 0 to 50% by weight, based on the total weight of the silanes.

9. The anode active material for lithium ion batteries as claimed in claim 4 , wherein the granular silicon is produced by deposition of a reaction gas on seed crystals composed of silicon in a fluidized bed.

10. The anode active material for lithium ion batteries as claimed in claim 4 , wherein the pyrolysis is carried out at a temperature of the fluidized bed in the reaction region of from 700° C. to 1000° C.

11. An anode for lithium ion batteries which contains one or more anode active materials as claimed in claim 1 .

12. A lithium ion battery comprising a cathode, an anode, a separator and an electrolyte, wherein the anode contains one or more anode active materials as claimed in claim 1 .

13. The lithium ion battery as claimed in claim 12 , wherein the anode is only partially lithiated in the fully charged lithium ion battery.

14. The lithium ion battery as claimed in claim 13 , wherein the ratio of lithium atoms to silicon atoms in the anode material is ≤3.5 in the fully charged state of the lithium ion battery.

Assignees

• Wacker Chemie Ag

Inventors

• Pfeiffer Jürgen
• Hanelt Eckhard
• Hertlein Harald
• Hesse Karl
• Maurer Robert

Classifications

• H01M4/386 Primary

  Silicon or alloys based on silicon · CPC title

• B01J8/24

  according to "fluidised-bed" technique (B01J8/20 takes precedence) · CPC title

• C01B33/03

  by decomposition of silicon halides or halosilanes or reduction thereof with hydrogen as the only reducing agent · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• C01P2004/51

  Particles with a specific particle size distribution · CPC title