Active material powder for use in a negative electrode of a battery and a battery comprising such an active material powder

Patent metadata

Field	Value
Publication number	US-11450849-B2
Application number	US-201916437199-A
Country	US
Kind code	B2
Filing date	Jun 11, 2019
Priority date	Jun 15, 2018
Publication date	Sep 20, 2022
Grant date	Sep 20, 2022

Abstract

An active material powder for use in a negative electrode of a battery, wherein the active material powder comprises active material particles, wherein the active material particles comprise silicon-based particles, wherein when said active material powder is crossed by a plane, then at least 65% of the discrete cross-sections of the silicon-based particles included in that plane, satisfy optimized conditions of shape and size, allowing the battery containing such an active material powder to achieve a superior cycle life and a production method of such an active material powder.

First claim

The invention claimed is:

1. An active material powder for use in a negative electrode of a battery, said active material powder comprising active material particles, wherein the active material particles comprise silicon-based particles, said active material powder being characterized in that, when it is crossed by a plane so that at least 1000 discrete cross-sections of silicon-based particles, having a perimeter and an area, are included in said plane, then at least 65% of said at least 1000 discrete cross-sections of silicon-based particles observed by means of SEM or TEM have both:
a shape factor SF=d disc /d max superior or equal to 0.4 and inferior or equal to 0.8, and
a d max superior or equal to 10 nm and inferior or equal to 250 nm,

wherein d max is the linear distance between the two most distant points of the perimeter of a discrete cross-section of a silicon-based particle, and wherein d disc is the diameter of a discus having an identical area as the one of said discrete cross-section of said silicon-based particle, said diameter d disc being calculated using the following formula:

area
⁢

⁢
disc

=

π
×

(

d

d
⁢
i
⁢
s
⁢
c

2

)

2

=

area
⁢

⁢
Si

,

wherein
⁢

⁢

d

d
⁢
i
⁢
s
⁢
c

=

2
×

area
⁢

⁢
Si

π

.

2. The active material powder according to claim 1 , wherein at least 70% of the at least 1000 discrete cross-sections of said silicon-based particles included in the plane crossing the active material powder have both a shape factor SF=d disc /d max superior or equal to 0.4 and inferior or equal to 0.8, and a d max superior or equal to 10 nm and inferior or equal to 250 nm.

3. The active material powder according to claim 1 , wherein the shape factor SF=d disc /d max is superior or equal to 0.5 and inferior or equal to 0.8.

4. The active material powder according to claim 1 , wherein the active material powder further comprises a matrix material and the silicon-based particles are embedded in the matrix material.

5. The active material powder according to claim 1 , wherein the active material powder has a volume-based particle size distribution wherein the d10 is comprised between 1 μm and 10 μm, and the d50 is comprised between 3 μm and 30 μm, and the d90 is comprised between 5 μm and 50 μm.

6. The active material powder according to claim 1 , characterised in that it has an oxygen content and an average silicon content A with respect to the total weight of the active material powder expressed as wt %, wherein the oxygen content expressed in wt % is less than 35% of A.

7. The active material powder according to claim 1 , characterised in that it has a BET value of less than 10 m 2 /g.

8. The active material powder according to claim 1 , characterised in that the active material particles have a porosity of less than 20% in volume.

9. The active material powder according to claim 1 , wherein the active material powder comprises at least 90% by weight of said active material particles with respect to the total weight of the active material powder.

10. The active material powder according to claim 4 , wherein the matrix material is a carbon-based matrix material.

11. The active material powder according to claim 4 , characterised in that the matrix material is at least one of the following compounds: polyvinyl alcohol (PVA), polyvinyl chloride (PVC), sucrose, coal-tar pitch and petroleum pitch, or the matrix material is a thermally decomposed product of at least one of said compounds.

12. The active material powder according to claim 4 , characterised in that the active material powder also contains graphite, wherein the graphite is not embedded in the matrix material.

13. The active material powder according to claim 1 , characterized in that the silicon-based particles have a chemical composition having at least 65% by weight of silicon.

14. The active material powder according to claim 13 , wherein the silicon-based particles are free of other elements than Si and O.

15. A battery comprising the active material powder of claim 1 .

16. An electronic device comprising a battery according to claim 15 .

Assignees

• Umicore Nv

Inventors

• Marx Nicolas
• Put Stijn
• Bridel Jean-Sébastien
• Moeremans Boaz

Classifications

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title

• H01M4/362 Primary

  Composites · CPC title

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M4/386 Primary

  Silicon or alloys based on silicon · CPC title

• C01P2004/04

  obtained by TEM, STEM, STM or AFM · CPC title