Nano-sized silicon
A method includes combining fumed silicon oxide with a metal to form silicon having an average particle size of less than approximately 100 nm. The silicon can be incorporated into an anode of a lithium ion cell.
1. A lithium ion cell, comprising:
(1) a cathode,
(2) an anode, comprising a silicon-containing product,
(3) a separator, between the cathode and the anode, and
(4) a non-aqueous electrolyte,
wherein the silicon-containing product comprises
(i) silicon having an average particle size of less than approximately 100 nm
(ii) magnesium oxide, and
(iii) magnesium silicate.
2. The cell of claim 1 , wherein the silicon oxide has an average particle size of less than approximately 80 nm.
3. The cell of claim 1 , wherein the silicon has an average particle size of less than approximately 50 nm.
4. The cell of claim 1 , wherein the silicon-containing material further comprises lithium.
5. The cell of claim 1 , wherein the silicon-containing product comprises (i) at least approximately 80 wt % of the silicon.
6. The cell of claim 1 , wherein the silicon-containing product comprises (i) at least approximately 85 wt % of the silicon.
7. The cell of claim 1 , wherein the silicon-containing product comprises (i) at least approximately 90 wt % of the silicon.
8. The cell of claim 1 , wherein the silicon-containing product comprises (ii) approximately 1.5 to 52 wt % of the magnesium oxide.
9. The cell of claim 1 , wherein the silicon-containing product comprises (iii) approximately 11 to 29 wt % of the magnesium silicate.
10. The cell of claim 1 , wherein the silicon-containing product comprises
(i) at least approximately 80% of the silicon,
(ii) at least approximately 1.5 wt % of the magnesium oxide, and
(iii) at least approximately 11 wt % of the magnesium silicate.
11. The cell of claim 1 , wherein (2) the anode further comprises at least one binder, and at least one conductive aid.
12. The cell of claim 11 , wherein the at least one binder is present in an amount of approximately 5 to approximately 20 wt %.
13. A silicon-containing product, comprising:
(i) silicon having an average particle size of less than approximately 100 nm,
(ii) magnesium oxide, and
(iii) magnesium silicate.
14. The silicon-containing product of claim 13 , wherein the silicon has an average particle size of less than approximately 50 nm.
15. The silicon-containing product of claim 13 , further comprising (iv) lithium.
16. The silicon-containing product of claim 13 , comprising (i) at least approximately 80 wt % of the silicon.
17. The silicon-containing product of claim 13 , comprising (i) at least approximately 85 wt % of the silicon.
18. The silicon-containing product of claim 13 , comprising (ii) approximately 1.5 to 52 wt % of the magnesium oxide.
19. The silicon-containing product of claim 13 , comprising (iii) approximately 11 to 29 wt % of the magnesium silicate.
20. The silicon-containing product of claim 13 , comprising
(i) at least approximately 80% of the silicon,
(ii) at least approximately 1.5 wt % of the magnesium oxide, and
(iii) at least approximately 11 wt % of the magnesium silicate.
21. A method of preparing the silicon-containing product of claim 13 , comprising:
combining reactants comprising
(a) fumed silicon oxide, and
(b) a metal, and
heating the reactants to a temperature greater than approximately 100° C. to form the silicon having an average particle size of less than approximately 100 nm.
22. The method of claim 21 , wherein the fumed silicon oxide has an average particle size of less than approximately 100 nm.
23. The method of claim 21 , wherein the fumed silicon oxide has an average particle size of less than approximately 50 nm.
24. The method of claim 21 , wherein the heating comprises a heating at a rate of less than approximately 5° C./min.
25. The method of claim 21 , wherein the combining reactants comprises combining the fumed silicon oxide and an excess of the metal.
26. The method of claim 21 , further comprising removing at least a portion of metal oxide formed on the silicon.
27. The method of claim 21 , wherein the reactants further comprise a material capable of dissolving an oxide on the metal.
28. The method of claim 27 , wherein the material comprises a halide.
29. The method of claim 21 , wherein the reactants further comprise a lithium-containing material.