Electroactive materials for metal-ion batteries

Patent metadata

Field	Value
Publication number	US-10964940-B1
Application number	US-202017024383-A
Country	US
Kind code	B1
Filing date	Sep 17, 2020
Priority date	Sep 17, 2020
Publication date	Mar 30, 2021
Grant date	Mar 30, 2021

Abstract

This invention relates to particulate electroactive materials consisting of a plurality of composite particles, wherein the composite particles comprise: (a) a porous carbon framework including micropores and mesopores having a total volume of 0.5 to 1.5 cm3/g; and (b) silicon located at least within the micropores of the porous carbon framework in a defined amount relative to the volume of the micropores and mesopores. At least 20 wt % of the silicon is characterized as surface silicon by thermogravimetric analysis.

First claim

The invention claimed is:

1. A particulate material consisting of a plurality of composite particles, wherein the composite particles comprise:
(a) a porous carbon framework comprising micropores and mesopores,
wherein the micropores and mesopores have a total pore volume as measured by gas adsorption of P 1 cm 3 /g, wherein P 1 represents a natural number having a value of from 0.5 to 1.5,
wherein the PD 90 pore diameter is at least 3 nm and less than 12 nm; and
wherein the micropore volume fraction based on P 1 is from 0.43 to 0.85; and

(b) a plurality of nanoscale elemental silicon domains located within the pores of the porous carbon framework,

wherein the particulate material comprises from 25 to 65 wt % silicon, and wherein at least 20 wt % of the silicon is surface silicon as determined by thermogravimetric analysis (TGA).

2. A particulate material according to claim 1 , wherein P 1 has a value of at least 0.65.

3. A particulate material according to claim 1 , wherein P 1 has a value of no more than 1.3.

4. A particulate material according to claim 1 , wherein the PD 90 pore diameter of the porous carbon framework is no more than 10 nm.

5. A particulate material according to claim 1 , wherein the micropore volume fraction of the porous carbon framework is at least 0.5, based on the total volume of micropores and mesopores.

6. A particulate material according to claim 1 , wherein the micropore volume fraction of the porous carbon framework is no more than 0.8, based on the total volume of micropores and mesopores.

7. A particulate material according to claim 1 , wherein the total volume of micropores in the porous carbon framework is at least 0.36 cm 3 /g.

8. A particulate material according to claim 1 , wherein the fractional volume of pores having a pore size of 5 nm or less is at least 0.8.

9. A particulate material according to claim 1 , wherein the total volume of pores having a diameter in the range of from greater than 50 nm to 100 nm is defined as P 2 cm 3 /g, wherein P 2 is no more than 0.2×P 1 .

10. A particulate material according to claim 1 , wherein the porous carbon framework has a BET surface area from 1200 to 3000 m 2 /g.

11. A particulate material according to claim 1 , comprising at least 30 wt % silicon.

12. A particulate material according to claim 1 , comprising no more than 60 wt % silicon.

13. A particulate material according to claim 1 , wherein the porous carbon framework is a steam-activated porous carbon framework.

14. A particulate material according to claim 1 , wherein the porous carbon framework comprises at least 95 wt % carbon.

15. A particulate material according to claim 1 , wherein the weight ratio of silicon to the porous carbon framework is at least 0.75×P 1 .

16. A particulate material according to claim 1 , wherein the weight ratio of silicon to the porous carbon framework is no more than 1.9×P 1 .

17. A particulate material according to claim 1 , wherein at least 30 wt % of the silicon is surface silicon as determined by thermogravimetric analysis (TGA).

18. A particulate material according to claim 1 , wherein at least 40 wt % of the silicon is surface silicon as determined by thermogravimetric analysis (TGA).

19. A particulate material according to claim 1 , wherein no more than 10 wt % of the silicon is coarse bulk silicon as determined by thermogravimetric analysis (TGA).

20. A particulate material according to claim 1 , wherein no more than 5 wt % of the silicon is coarse bulk silicon as determined by thermogravimetric analysis (TGA).

21. A particulate material according to claim 1 , wherein at least a portion of the micropores and/or mesopores comprise void space that is fully enclosed by the silicon.

22. A particulate material according to claim 1 , wherein the volume of micropores and mesopores of the composite particles, in the presence of silicon, as measured by nitrogen gas adsorption, is no more than 0.15×P 1 .

23. A particulate material according to claim 1 , wherein the composite particles are obtained by chemical vapor infiltration (CVI) of a silicon-containing precursor into the pore structure of a porous carbon framework.

24. An electrode comprising a particulate material as defined in claim 1 in electrical contact with a current collector.

25. A rechargeable metal-ion battery comprising:
(i) an anode, wherein the anode comprises an electrode as described in claim 24 ;
(ii) a cathode comprising a cathode active material capable of releasing and reabsorbing metal ions; and
(iii) an electrolyte between the anode and the cathode.

26. A process for preparing composite particles, the process comprising the steps of:
(a) providing a plurality of porous carbon particles comprising micropores and/or mesopores, wherein:
(i) the micropores and mesopores have a total pore volume as measured by gas adsorption of P 1 cm 3 /g, wherein P 1 represents a natural number having a value of from 0.5 to 1.5;
(ii) the PD 90 pore diameter is at least 3 nm and less 12 nm; and
(iii) the micropore volume fraction based on P 1 is from 0.43 to 0.85;

(b) contacting the plurality of porous carbon particles with a gas comprising 0.5 to 20 vol % of a silicon precursor gas at a temperature from 400 to 700° C.

Assignees

• Nexeon Ltd

Inventors

• Mason Charles
• Taylor Richard
• Friend Christopher Michael

Classifications

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M4/386 Primary

  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

• H01M4/62

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

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title