Composite powder for use in an anode of a lithium ion battery, method for manufacturing a composite powder and lithium ion battery

Patent metadata

Field	Value
Publication number	US-11329275-B2
Application number	US-201615569400-A
Country	US
Kind code	B2
Filing date	Apr 26, 2016
Priority date	Apr 28, 2015
Publication date	May 10, 2022
Grant date	May 10, 2022

Abstract

Composite powder for use as electrochemically active material in an anode of a lithium ion battery, whereby the particles of the composite powder comprise a carbon-based matrix material and silicon particles embedded in this matrix material, whereby the silicon particles and the matrix material have an interface, characterized in that at this interface there are Si—C chemical bonds present.

First claim

The invention claimed is:

1. A composite powder for use in an anode of a lithium ion battery, the composite powder comprising a carbon-based matrix material and silicon particles embedded in the matrix material, wherein an interface is present between the matrix material and the silicon particles, wherein Si—C chemical bonds are present at the interface and said interface is free of crystalline silicon carbide.

2. The composite powder of claim 1 , wherein the composite powder is free of crystalline silicon carbide.

3. The composite powder of claim 1 , wherein said silicon particles have an average particle size of 500 nm or less.

4. The composite powder of claim 1 , wherein the carbon matrix material comprises pitch or thermally decomposed pitch.

5. The composite powder of claim 1 , wherein at the interface the following relation holds: 3.5*(Si 4+ +Si 3+ )+1.5*(Si 2+ +Si 1+ )>2*O 2− , wherein Si 4+ is the relative prevalence of tetravalent positively charged Si atoms, Si 3+ is the relative prevalence of trivalent positively charged Si atoms, Si 2+ is the relative prevalence of bivalent positively charged Si atoms, Si 1+ is the relative prevalence of monovalent positively charged Si atoms and O 2− is the relative prevalence of bivalent negatively charged oxygen atoms, all expressed as atomic fractions.

6. The composite powder of claim 5 , wherein Si 4+ , Si 3+ , Si 2+ , Si 1+ and O 2− are as determined by X-ray photoelectron spectroscopy measurements, wherein the sum of Si 4+ and Si 3+ and the sum of Si 2+ and Si 1+ are determined.

7. A lithium ion battery having an anode comprising the composite powder of claim 1 .

8. A method of manufacturing a composite powder, the method comprising:
a) providing silicon particles, wherein the silicon particles have surfaces free of any oxides;
b) contacting the surfaces of the silicon particles with an oxygen-free carbon-containing compound at a temperature of less than 300° C. in order to obtain a chemical reaction between silicon on the surfaces of the silicon particles and the carbon-containing compound;
c) mixing the silicon particles with a carbon precursor, which can be thermally decomposed to carbon; and
d) thermally treating the mixture from step C thereby effecting a thermal decomposition of the carbon precursor.

9. The method of claim 8 , wherein step D is performed at a temperature of more than 400° C. and not exceeding 1075° C.

10. The method of claim 9 , wherein step D is performed at a temperature not exceeding 1020° C.

11. The method of claim 8 , wherein the silicon particles have an average particle size of 500 nm or less.

12. The method of claim 8 , wherein the carbon-containing compound of step B comprises an oxygen-free aromatic compound or an oxygen-free alkane with more than four carbon atoms.

13. The method of claim 8 , wherein the carbon precursor of step C is pitch.

14. The method of claim 8 , wherein it is a method for preparing the composite powder of claim 1 .

15. A lithium ion battery having an anode comprising a composite powder formed in the method of claim 8 .

Assignees

• Umicore Nv

Inventors

• Put Stijn
• Van Genechten Dirk
• Bridel Jean-Sébastien

Classifications

• H01M10/052

  Li-accumulators · CPC title

• H01M4/364 Primary

  as mixtures · CPC title

• H01M10/0525

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

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title