Sacrificial substrates for silicon-carbon composite materials
Methods of forming a composite material film can include providing a layer comprising a carbon precursor and silicon particles on a sacrificial substrate. The methods can also include pyrolysing the carbon precursor to convert the precursor into one or more types of carbon phases to form the composite material film, whereby the sacrificial substrate has a char yield of about 10% or less.
1. A method of forming a composite material film, the method comprising:
providing a layer comprising a carbon precursor and silicon particles on a sacrificial substrate, wherein the layer comprises a mixture comprising a solvent;
drying the mixture on the sacrificial substrate prior to pyrolysing, wherein the dried mixture comprises from about 10% to about 30% of the solvent;
forming the dried mixture on the sacrificial substrate into a plurality of dried mixtures on sacrificial substrates, and stacking the plurality prior to pyrolyzing; and
pyrolysing the carbon precursor to convert the precursor into one or more types of carbon phases to form the composite material film, whereby the sacrificial substrate has a char yield of about 10% or less.
2. The method of claim 1 , wherein the sacrificial substrate has a char yield of about 7% or less.
3. The method of claim 2 , wherein the sacrificial substrate has a char yield of about 5% or less.
4. The method of claim 3 , wherein the sacrificial substrate has a char yield of about 3% or less.
5. The method of claim 4 , wherein the sacrificial substrate has a char yield of about 1% or less.
6. The method of claim 5 , wherein the sacrificial substrate has a char yield of about 0%.
7. The method of claim 1 , wherein the sacrificial substrate comprises polymethylpentene (PMP), acetal copolymer, acrylonitrile butadiene styrene (ABS), paraffin wax, polyethylene oxide, polyethylene, polypropylene, poly(propylene carbonate), cellulose acetate, or a combination thereof.
8. The method of claim 7 , wherein the sacrificial substrate comprises polyethylene, polypropylene, poly(propylene carbonate), polymethylpentene, or a combination thereof.
9. The method of claim 1 , wherein the sacrificial substrate is insoluble in the solvent.
10. The method of claim 1 , wherein the solvent comprises N-Methylpyrrolidone (NMP).
11. The method of claim 1 , wherein the solvent comprises water.
12. The method of claim 11 , wherein the carbon precursor comprises a water soluble polymer.
13. The method of claim 1 , wherein the composite material film comprises the one or more types of carbon phases at greater than 0% to about 20% by weight.
14. The method of claim 1 , wherein the composite material film comprises the silicon particles at greater than about 50% to about 99% by weight.
15. The method of claim 1 , wherein the composite material film further comprises graphite particles.
16. The method of claim 1 , wherein the composite material film is substantially electrochemically active.
17. The method of claim 1 , wherein pyrolysing forms the composite material film as a self-supported structure.
18. The method according to claim 1 , comprising:
providing a first electrode, wherein providing the first electrode comprises providing the composite material film formed by the method of claim 1 ;
providing a second electrode; and
providing an electrolyte.
19. The method of claim 18 , wherein providing the first electrode comprises providing the composite material film as a self-supported electrode.
20. The method of claim 18 , wherein providing the first electrode comprises providing the composite material film on a current collector.
21. The method of claim 18 , wherein the first electrode is an anode and the second electrode is a cathode.
22. The method of claim 18 , comprising:
forming an electrochemical device;
wherein forming the electrochemical device includes providing the first electrode, providing the second electrode, and providing the electrolyte; and
wherein the electrochemical device is a battery.