Electrodes, electrochemical cells, and methods of forming electrodes and electrochemical cells
Electrodes and methods of forming electrodes are described herein. The electrode can be an electrode of an electrochemical cell or battery. The electrode includes a current collector and a film in electrical communication with the current collector. The film may include a carbon phase that holds the film together. The electrode further includes an electrode attachment substance that adheres the film to the current collector.
1. A method of forming a composite material film, the method comprising:
providing a mixture comprising a precursor and silicon particles; and
casting the mixture on a substrate;
drying the mixture to form a precursor film; and
pyrolysing the precursor film to convert the precursor into one or more types of carbon phases to form the composite material film, wherein pyrolysing the precursor film comprises applying pressure to the precursor film.
2. The method of claim 1 , wherein applying pressure to the precursor film comprises applying at least 2 bars of pressure.
3. The method of claim 1 , further comprising cycling the composite material film.
4. The method of claim 3 , wherein the composite material film remains substantially flat and substantially free of wrinkles during cycling.
5. The method of claim 1 , wherein pyrolysing comprises heating the precursor film to about 900° C. to about 1350° C.
6. The method of claim 1 , further comprising removing the precursor film from the substrate prior to pyrolysing the precursor film.
7. The method of claim 1 , wherein the composite material film is self-supported.
8. The method of claim 1 , wherein at least one of the one or more types of carbon phases is a substantially continuous phase that holds the composite material film together such that the silicon particles are distributed throughout the composite material film.
9. The method of claim 8 , wherein the at least one of the one or more types of carbon phases that is a substantially continuous phase comprises hard carbon.
10. The method of claim 1 , wherein providing the mixture comprises providing the silicon particles at greater than 0% to about 90% by weight.
11. The method of claim 10 , wherein the composite material film comprises the silicon particles at more than about 50% by weight.
12. The method of claim 11 , wherein the composite material film comprises the silicon particles at about 60% to about 80% by weight.
13. The method of claim 1 , wherein the precursor comprises polyamic acid or polyimide.
14. The method of claim 1 , wherein providing the mixture comprises providing conductive particles in the mixture.
15. The method of claim 14 , wherein providing the mixture comprises providing metal particles in the mixture.
16. The method of claim 1 , wherein providing the mixture comprises providing graphite particles in the mixture.
17. The method of claim 1 , wherein the composite material film is substantially electrochemically active and electrically conductive.
18. The method of claim 17 , wherein the composite material film is an anode.