Silicon material and method of manufacture
A silicon material can include a composition with at least about 50% silicon, at most about 45% carbon, and at most about 10 % oxygen. The silicon material can have an external expansion that is less than about 40%. The silicon material can include silicon nanoparticles, which can cooperatively form clusters. The silicon nanoparticles can be porous.
1. A silicon material comprising:
a primary structure comprising silicon nanoparticles with primary sizes between about 2 nanometers (nm) and about 150 nm;
a secondary structure comprising clusters of the silicon nanoparticles, the clusters having a cluster size between about 100 and 1000 nm; and
a composition of about 1-10% carbon by mass, about 5-10% oxygen by mass, and about 80-94% silicon by mass.
2. The silicon material of claim 1 , wherein the silicon nanoparticles comprise a non-spheroidal morphology.
3. The silicon material of claim 1 , wherein a size distribution of the silicon nanoparticles is substantially uniform.
4. The silicon material of claim 1 , wherein the silicon nanoparticles form an interconnected network in the clusters.
5. The silicon material of claim 1 , wherein the carbon of the composition comprises graphite.
6. The silicon material of claim 1 , further comprising a carbonaceous coating comprising at least one of amorphous carbon, polymer, or graphitic carbon.
7. The silicon material of claim 6 , wherein the carbonaceous coating comprises PAN, wherein the PAN is cyclized.
8. The silicon material of claim 1 , wherein the silicon nanoparticles cooperatively form primary pores within the clusters, wherein a pore size of the primary pores is between 0.5 nm and 200 nm.
9. The silicon material of claim 1 , wherein the silicon nanoparticles are manufactured from silica fumes.
10. The silicon material of claim 1 , wherein the carbon composition is selected based on at least one of a target electrical conductivity or a target ionic conductivity of the silicon material.
11. A battery anode comprising a porous silicon material with a composition of at least 50% silicon by mass and between 1-45% carbon by mass, wherein an external volume expansion of the porous silicon material is at most 40%, wherein the porous silicon material comprises an internal surface area between about 50-1500 m 2 /g.
12. The battery anode of claim 11 , wherein an external surface area of the porous silicon material is between about 1-50 m 2 /g.
13. The battery anode of claim 11 , wherein the porous silicon material further comprises at most about 5% oxygen by mass.
14. The battery anode of claim 13 , wherein the silicon nanoparticles are non-spheroidal.
15. The battery anode of claim 13 , wherein the silicon nanoparticles are manufactured from fumed silica.
16. The battery anode of claim 13 , wherein the silicon nanoparticles cooperatively form clusters with a characteristic size between about 100-1000 nm.
17. The battery anode of claim 11 , wherein the porous silicon material comprises a carbonaceous coating.
18. The battery anode of claim 17 , wherein the carbonaceous coating comprises polyacrylonitrile.
19. The battery anode of claim 11 , wherein the porous silicon material further comprises a substantially isotropic tortuosity.