Formation of silicon-carbon composite particles by magnesiothermic reduction of silicon oxide for lithium-ion batteries

Patent metadata

Field	Value
Publication number	US-2026074183-A1
Application number	US-202519320560-A
Country	US
Kind code	A1
Filing date	Sep 5, 2025
Priority date	Sep 6, 2024
Publication date	Mar 12, 2026
Grant date	—

Abstract

A method of making silicon-carbon composite particles is disclosed. The method includes: (A1) carrying out metallothermic reduction on initial particles comprising silicon oxide in the presence of a metal to form first intermediate particles comprising (1) an oxide of the metal and (2) silicon; (A2) forming a termination material on and in the first intermediate particles to form second intermediate particles; (A3) selectively removing the oxide of the metal from the second intermediate particles to form third intermediate particles; and (A4) forming a protective material on and in the third intermediate particles to form the silicon-carbon composite particles. In some implementations, the metal comprises magnesium or a magnesium-aluminum alloy. Silicon-carbon composite particles, lithium-ion rechargeable batteries, and other related processes and components are also disclosed.

First claim

1 . A method of making silicon-carbon composite particles, the method comprising:
(A1) carrying out metallothermic reduction on initial particles comprising silicon oxide in the presence of a metal to form first intermediate particles comprising (1) an oxide of the metal and (2) elemental silicon; (A2) forming a termination material on and in the first intermediate particles to form second intermediate particles; (A3) selectively removing the oxide of the metal from the second intermediate particles to form third intermediate particles; and (A4) forming a protective material on and in the third intermediate particles to form the silicon-carbon composite particles.

2 . The method of claim 1 , wherein:
the metal comprises magnesium or a magnesium-aluminum alloy.

3 . The method of claim 1 , wherein:
the metal is in vapor form during the metallothermic reduction (A1).

4 . The method of claim 1 , further comprising:
(B1) forming a mixture of particles of the metal and the first intermediate particles, wherein: the forming of the mixture (B1) is carried out before the carrying out of the metallothermic reduction (A1).

5 . The method of claim 1 , wherein:
the silicon oxide comprises silicon dioxide.

6 . The method of claim 1 , wherein:
the silicon oxide is present as silicon oxide particles having an average size in a range of about 50 nm to about 10 μm.

7 . The method of claim 1 , further comprising:
(B2) pyrolyzing precursor particles to form the initial particles, the initial particles additionally comprising carbon, the precursor particles comprising the silicon oxide and a carbon precursor.

8 . The method of claim 7 , wherein:
the carbon precursor is a polymer.

9 . The method of claim 7 , wherein:
the carbon precursor is a resin.

10 . The method of claim 1 , wherein:
the first intermediate particles additionally comprise magnesium silicide; and the method further comprises: (B3) annealing the first intermediate particles to remove the magnesium silicide from the first intermediate particles.

11 . The method of claim 1 , wherein:
the termination material comprises carbon.

12 . The method of claim 11 , wherein:
the forming of the termination material (A2) comprises chemical vapor deposition of the carbon from a hydrocarbon precursor.

13 . The method of claim 12 , wherein:
the hydrocarbon precursor is selected from acetylene and propylene.

14 . The method of claim 1 , wherein:
the termination material comprises a silicon oxide.

15 . The method of claim 14 , wherein:
the forming of the termination material (A2) comprises carrying out oxidation of the elemental silicon of the first intermediate particles.

16 . The method of claim 1 , wherein:
the selectively removing (A3) comprises etching the second intermediate particles with an acid.

17 . The method of claim 1 , wherein:
the protective material comprises carbon.

18 . The method of claim 17 , wherein:
the forming of the protective material (A4) comprises chemical vapor deposition of the carbon from a hydrocarbon precursor.

19 . The method of claim 18 , wherein:
the hydrocarbon precursor is selected from acetylene and propylene.

20 . The method of claim 1 , wherein:
the silicon-carbon composite particles exhibit a Brunauer-Emmett-Teller specific surface area (BET-SSA) in a range of about 0.5 to about 20 m 2 /g.

21 . The method of claim 20 , wherein:
the BET-SSA is in a range of about 1 to about 10 m 2 /g.

22 . The method of claim 1 , further comprising:
(B4) depositing silicon on the third intermediate particles.

23 . The method of claim 22 , wherein:
the depositing of the silicon (B4) comprises chemical vapor deposition (CVD) of the silicon.

24 . The silicon-carbon composite particles made according to the method of claim 1 .

25 . A Li-ion rechargeable battery, comprising:
an anode comprising the silicon-carbon composite particles of claim 24 ; a cathode; and an electrolyte ionically coupling the anode and the cathode.

Assignees

• Sila Nanotechnologies Inc

Inventors

• Kajdos Adam Paul
• Lulevich Valentin
• Fevre Mareva
• Guzman Iii Ramon Felix
• Knutson Evan Neil
• Yushin Gleb Nikolayevich

Classifications

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01M4/1395

  of electrodes based on metals, Si or alloys · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M2004/021

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

• H01M4/386

  Silicon or alloys based on silicon · CPC title