Negative electrode material for a rechargeable battery, and method for producing it

Patent metadata

Field	Value
Publication number	US-9601758-B2
Application number	US-201314652950-A
Country	US
Kind code	B2
Filing date	Dec 17, 2013
Priority date	Dec 20, 2012
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

The invention relates to a negative electrode powder for a lithium-ion rechargeable battery comprising a mixture comprising carbon and SiO x , with 0<x<1, wherein the SiO x consists of a nanometric composite of crystalline SiO 2 and amorphous Si. The method for preparing the powder comprises the steps of providing an aqueous solution comprising an anti-agglomeration agent, dispersing a silicon comprising organic compound in the aqueous solution, hydrothermally treating the aqueous solution at a temperature between 90 and 180° C. for a period of 0.5 to 24 h, preferably between 110 and 140° C. for a period of 0.5 to 4 h, thereby forming a suspension of SiO 2 and Si in the aqueous solution, evaporating the solution, thereby obtaining a slurry, subjecting the slurry to a coking process whereby a solid residue is formed, calcining the solid residue at a temperature between 500 and 1300° C., preferably between 600 and 1000° C., in a non-oxidizing atmosphere.

First claim

The invention claimed is:

1. A negative electrode powder for a lithium-ion rechargeable battery comprising a mixture including carbon and SiO x , with 0<x<1, wherein the SiO x comprises a composite of crystalline SiO 2 and amorphous Si wherein the mixing of SiO 2 and Si occurs over a scale of between 1 and 5 nm, characterized in that said mixture is free of SiO x domains that are larger than 100 nm.

2. The negative electrode powder of claim 1 , wherein said mixture is free of SiO x domains that are larger than 50 nm.

3. The negative electrode powder of claim 1 , wherein said mixture is free of SiO x domains that are larger than 20 nm.

4. The negative electrode powder of claim 1 , wherein said mixture is not a core-shell structure with a core of SiO x and a shell comprising carbon.

5. The negative electrode powder of claim 1 , wherein the powder has a d50 value between 0.8 and 8 μm.

6. The negative electrode powder of claim 1 , wherein the powder has a BET value of less than 5 m 2 /g.

7. The negative electrode powder of claim 1 , wherein 0.5<x<1.

8. The negative electrode powder of claim 1 , wherein in the mixture of carbon and SiO x the weight ratio SiO x :C is between 33:1 and 1:1.

9. The negative electrode powder of claim 1 , wherein the mixture further comprises M y O, wherein M is a metal with an oxidation number of z, with z * y=2, and wherein M is selected from the group consisting of Al, Ca, Mg, Ti, Li and combinations thereof.

10. A negative electrode comprising 50 to 95 wt % of the negative electrode powder of claim 1 , 2.5 to 25 wt % of a conductive agent and 5 to 25 wt % of a binder material.

11. A process for preparing the negative electrode powder of claim 1 , comprising:
providing an aqueous solution comprising an anti-agglomeration agent,
dispersing a silicon comprising organic compound in the aqueous solution,
hydrothermally treating the aqueous solution at a temperature between 90 and 180° C. for a period of 0.5 to 24 h, thereby forming a suspension of SiOx in the aqueous solution,
evaporating the solution, thereby obtaining a slurry,
subjecting the slurry to a coking process whereby a solid residue is formed, and
calcining the solid residue at a temperature between 500 and 1300° C. in a non-oxidizing atmosphere.

12. The process according to claim 11 , wherein the calcination of the solid residue is performed in a reducing atmosphere comprising H 2 or CH 4 .

13. A process for preparing the negative electrode powder of claim 1 , comprising:
providing a first aqueous solution comprising an anti-agglomeration agent,
dissolving an organic carbon source in a second solution,
dispersing a silicon comprising organic compound in the first aqueous solution,
hydrothermally treating the first aqueous solution at a temperature between 90 and 180° C. for a period of 0.5 to 24 h, thereby forming a suspension of SiOx in the first aqueous solution,
mixing the first aqueous solution and the second solution, thereby obtaining a third solution,
evaporating the third solution at a temperature below the boiling point of the second solution, thereby obtaining a slurry,
subjecting the slurry to a coking process whereby the organic carbon source is decomposed and a solid residue is formed, and
calcining the solid residue at a temperature between 500 and 1300° C. in a non-oxidizing atmosphere.

14. The process according to claim 11 , wherein the anti-agglomeration agent contains carbon.

15. The process according to claim 14 , wherein the anti-agglomeration agent comprises polyvinyl pyrrolidone or a vinyl pyrrolidone-vinyl ester copolymer.

16. The process according to claim 13 , wherein the second solution is a second aqueous solution, and the content of the organic carbon source in the second solution is between 100 and 300 g/l.

17. The process according to claim 13 , wherein quantities of the organic carbon source and the silicon comprising organic compound are provided so as to obtain a weight ratio SiO x :C between 33:1 and 1:1 in the mixture of carbon and SiO x .

Assignees

• Umicore Nv

Inventors

• Put Stijn
• Bridel Jean-Sebastien
• Zhao Hailei
• Wang Jing

Classifications

• H01M2004/027

  Negative electrodes · CPC title

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• H01M10/0525

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

• H01M10/052

  Li-accumulators · CPC title

• H01M4/364 Primary

  as mixtures · CPC title