Silicon particles for battery electrodes
Silicon particles for active materials and electro-chemical cells are provided. The active materials comprising silicon particles described herein can be utilized as an electrode material for a battery. In certain embodiments, the composite material includes greater than 0% and less than about 90% by weight of silicon particles. The silicon particles have an average particle size between about 0.1 μm and about 30 μm and a surface including nanometer-sized features. The composite material also includes greater than 0% and less than about 90% by weight of one or more types of carbon phases. At least one of the one or more types of carbon phases is a substantially continuous phase.
1. A method of forming a composite material, the method comprising:
providing a mixture comprising:
polyimide or a polyimide precursor;
silicon particles; and
graphite particles; and
pyrolysing the mixture to convert the polyimide or the polyimide precursor into one or more carbon phases to form the composite material such that:
the one or more carbon phases comprises hard carbon that is 10% to 25% by weight of the composite material and holds together the composite material, and
the silicon particles are between 50% and 90% by weight of the composite material distributed throughout the one or more carbon phases.
2. The method of claim 1 , further comprising:
casting the mixture on a substrate;
drying the mixture;
removing the dried mixture from the substrate; and
placing the dried mixture in a hot press.
3. The method of claim 1 , further comprising forming a battery electrode from the composite material.
4. The method of claim 1 , wherein providing the mixture comprises providing silicon particles having an average largest dimension of 10 nm to 40 μm.
5. The method of claim 1 , wherein providing the mixture comprises providing conductive particles in the mixture.
6. The method of claim 1 , wherein providing the mixture comprises providing copper, nickel, or stainless steel particles in the mixture.
7. The method of claim 1 , wherein the composite material comprises more than 60% by weight silicon particles.
8. The method of claim 1 , wherein the composite material comprises 60% to 80% by weight silicon particles.
9. The method of claim 1 , wherein the composite material comprises 70% to 80% by weight silicon particles.
10. The method of claim 1 , wherein the composite material comprises 5% to 15% by weight graphite particles.
11. The method of claim 10 , wherein the composite material comprises 10.5% by weight graphite particles.
12. The method of claim 1 , wherein the composite material is electrochemically active.
13. The method of claim 1 , wherein at least one of the carbon phases is electrochemically active and electrically conductive.
14. The method of claim 1 , wherein at least one of the carbon phases is a continuous phase.
15. A method of forming a battery cell, the method comprising:
forming an anode of the battery cell, the anode comprising silicon particles and a composite material, wherein the forming comprises:
providing a mixture comprising:
polyimide or a polyimide precursor;
silicon particles; and
graphite particles; and
pyrolysing the mixture to convert the polyimide or the polyimide precursor into one or more carbon phases to form the composite material such that:
the one or more carbon phases comprises hard carbon that is 10% to 25% by weight of the composite material and holds together the composite material, and
the silicon particles are between 50% and 90% by weight of the composite material distributed throughout the one or more carbon phases; and
separating the anode from a cathode of the battery cell with a separator and electrolyte of the battery cell.
16. The method of claim 15 , wherein forming the anode further comprises:
casting the mixture on a substrate;
drying the mixture;
removing the dried mixture from the substrate; and
placing the dried mixture in a hot press.
17. The method of claim 15 , wherein providing the mixture comprises providing silicon particles having an average largest dimension of 10 nm to 40 μm.
18. The method of claim 15 , wherein providing the mixture comprises providing conductive particles in the mixture.
19. The method of claim 15 , wherein providing the mixture comprises providing copper, nickel, or stainless steel particles in the mixture.
20. The method of claim 15 , wherein the composite material comprises more than 60% by weight silicon particles.
21. The method of claim 15 , wherein the composite material comprises 60% to 80% by weight silicon particles.
22. The method of claim 15 , wherein the composite material comprises 70% to 80% by weight silicon particles.
23. The method of claim 15 , wherein the composite material comprises 5% to 15% by weight graphite particles.
24. The method of claim 23 , wherein the composite material comprises 10.5% by weight graphite particles.
25. The method of claim 15 , wherein the composite material is electrochemically active.
26. The method of claim 15 , wherein at least one of the carbon phases is electrochemically active and electrically conductive.
27. The method of claim 15 , wherein at least one of the carbon phases is a continuous phase.