Silicon-carbide reinforced carbon-silicon composites
Silicon anode compositions are provided which include embedded silicon carbide nanofibers. Methods of production and use are further described.
1. A particulate comprising:
a carbon matrix carrying a plurality of silicon nanocrystals and a plurality of SiC nanofibers;
wherein the carbon matrix is the thermolysis product of a carbon matrix precursor.
2. The particulate of claim 1 , wherein the particulate has a composition that includes about 20 wt. % to about 90 wt. % carbon as the carbon matrix, about 5 wt. % to about 75 wt. % silicon metal as silicon nanocrystals, and about 1 wt. % to about 25 wt. % silicon-carbide as SiC nanofibers.
3. The particulate of claim 1 , wherein the SiC nanofibers have a length to width ratio of at least 5.
4. The particulate of claim 1 , wherein the particulate has a surface and an interior volume; and wherein the SiC nanofibers are entirely within the interior volume.
5. The particulate of claim 1 , wherein the SiC nanofibers have interior SiC segments and exterior SiC segments which extend outwardly from the surface of the particulate.
6. A material comprising:
a plurality of particulates having a diameter in the range of about 50 nm to about 50 μm, the particulates comprising a silicon-carbide reinforced carbon matrix carrying a plurality of silicon nanocrystals;
wherein the carbon matrix is the thermolysis product of a carbon matrix precursor.
7. The material of claim 6 , wherein the silicon-carbide reinforced carbon matrix includes a carbon-constituent material and SiC nanofibers.
8. The material of claim 7 , wherein the silicon-carbide reinforced carbon matrix includes SiC nanofibers carried within the carbon-constituent material and includes SiC nanofibers extending from a surface of the carbon-constituent material.
9. The material of claim 6 , wherein the particulates are spherical.
10. The material of claim 6 , wherein the silicon nanocrystals include greater than about 70 wt. % silicon metal.
11. The material of claim 10 , wherein the silicon nanocrystals include greater than about 95 wt. % silicon metal.
12. The material of claim 10 , wherein the silicon nanocrystals include a silicon alloy.
13. The material of claim 6 , wherein the particulates consist essentially of the silicon-carbide reinforced carbon matrix carrying the plurality of silicon nanocrystals.
14. The material of claim 6 further comprising a binder.
15. The material of claim 14 , wherein the silicon-carbide reinforced carbon matrix includes interior SiC nanofiber segments and exterior SiC nanofiber segments; and
wherein the material includes a silicon-carbide reinforced binder which includes the exterior SiC nanofiber segments admixed with the binder.
16. An anode comprising:
a plurality of particulates having a diameter in the range of about 50 nm to about 50 μm, and comprising a silicon-carbide reinforced carbon matrix carrying a plurality of silicon nanocrystals;
wherein the carbon matrix is the thermolysis product of a carbon matrix precursor.
17. The anode of claim 16 , wherein the anode has a specific capacity of about 1,000 to about 3,500 mAh/g.
18. The anode of claim 16 further comprising a current collector carrying the plurality of particulates.
19. The anode of claim 18 , wherein the current collector carries an admixture of a binder and the plurality of particulates.
20. The anode of claim 19 , wherein the admixture further includes a conductor.