Composites of porous nano-featured silicon materials and carbon materials

1. A composite material comprising nanoscale silicon and carbon, wherein the nanoscale silicon is disposed within a carbon shell and forms webbing that defines an internal void structure of the composition, and wherein the composite material comprises:

a silicon content between 20% to 70% by weight;

(ii) a specific surface area of less than 5 m 2 /g;

(iii) a pore volume between 0.001 and 0.2 cm 3 /g; and

(iv) a pore volume distribution comprising less than 30% micropores, less than 30% mesopores, and greater than 50% macropores.

2. The composite material of claim 1 , wherein the silicon content is 40% to 60% by weight.

3. The composite material of claim 1 , wherein the specific surface area of the composite is from 0.1 m 2 /g to less than 5 m 2 /g.

4. The composite material of claim 3 , wherein the pore volume of the composite is between 0.01 cm 3 /g and 0.1 cm 3 /g.

5. The composite material of claim 3 , wherein the pore volume distribution of the composite comprises less than 10% micropores, less than 10% mesopores, and greater than 80% macropores.

6. An electrode comprising the composite material according to claim 1 .

7. The electrode of claim 6 , wherein the electrode is an anode.

8. An energy storage device comprising the composite material according to claim 1 .

9. The energy storage device of claim 8 , wherein the device is a lithium ion battery.

10. A method for producing the composite according to claim 1 , the method comprising:

a) suspending particles of a silicon alloy in a liquid medium containing a dissolved acid;

b) storing the suspended particles for a period of time at sufficient temperature to allow for etching away of metal cations from the silicon alloy to yield porous silicon particles with nano-sized features;

c) removing the liquid medium to yield dried porous silicon particles with nano-sized features;

d) blending a mixture of polymer precursors with the porous silicon particles with nano-sized features;

e) storing the mixture of polymer precursors and the porous silicon particles with nano-sized features for a period of time at sufficient temperature to allow for impregnation and polymerization of the polymer precursors within the porous silicon particles with nano-sized features to yield polymer-impregnated silicon particles with nano-sized features; and

f) carbonization of the polymer-impregnated silicon particles with nano-sized features to yield the composite material.

11. The composite of claim 1 , wherein the nanoscale silicon comprises a surface area of 30 to 120 m 2 /g, a pore volume of 0.09 to 0.18 cm 3 /g, and wherein the pore volume of the nanoscale silicon comprises 5 to 15% micropores, 45-55% mesopores and 30-45% macropores.

12. A composite material comprising nanoscale silicon and carbon, wherein the nanoscale silicon is disposed within a carbon shell and forms a webbing that defines an internal void structure of the composite, and wherein the composite material comprises:

(i) a silicon content between 20% to 70% by weight;

(ii) a specific surface area between 0.1 and 10 m 2 /g;

(iii) a pore volume between 0.001 and 0.2 cm 3 /g; and

(iv) a pore volume distribution comprising less than 30% macropores, less than 30% mesopores, and greater than 50% micropores.

13. The composite material of claim 12 , wherein the silicon content is 20% to 40% by weight.

14. The composite material of claim 12 , wherein the specific surface area of the composite is between 5 m 2 /g and 10 m 2 /g.

15. The composite material of claim 12 , wherein the pore volume of the composite is between 0.01 cm 3 /g and 0.1 cm 3 /g.

16. An electrode comprising the composite material according to claim 12 .

17. The composite material of claim 12 , wherein the silicon content is 40% to 60% by weight.