Binding agents for electrochemically active materials and methods of forming the same
In some embodiments, an electrode can include a current collector, a composite material in electrical communication with the current collector, and at least one phase configured to adhere the composite material to the current collector. The current collector can include one or more layers of metal, and the composite material can include electrochemically active material. The at least one phase can include a compound of the metal and the electrochemically active material. In some embodiments, a composite material can include electrochemically active material. The composite material can also include at least one phase configured to bind electrochemically active particles of the electrochemically active material together. The at least one phase can include a compound of metal and the electrochemically active material.
1. A method of forming an electrode, the method comprising:
providing a current collector comprising one or more layers of metal; providing a precursor comprising from greater than 0% to about 99% by weight of electrochemically active material; and
heating the precursor and the current collector to form a composite material and at least one phase between the composite material and the current collector;
wherein the at least one phase is configured to adhere the composite material to the current collector, and wherein the at least one phase comprises a compound of the metal and the electrochemically active material, and
wherein said at least one phase comprises localized phases comprising particles of said compound surrounded by the composite material, the localized phases scattered across a plane between the current collector and the composite material to a depth in the composite material of 10% or less of composite material thickness.
2. The method of claim 1 , wherein the current collector comprises copper, nickel, iron, titanium, molybdenum, stainless steel, chromium, aluminum, or a combination thereof.
3. The method of claim 1 , wherein the electrochemically active material comprises silicon, graphite, germanium, tin, silicon oxide (SiOx), aluminum, or a combination thereof.
4. The method of claim 1 , wherein the compound comprises a metal silicide.
5. The method of claim 4 , wherein the metal silicide comprises copper silicide, nickel silicide, chromium silicide, aluminum silicide, titanium silicide, or a combination thereof.
6. The method of claim 1 , wherein the current collector has a surface roughness from about 0.025 Rz/μm to about 25 Rz/μm.
7. The method of claim 6 , wherein the surface roughness is from about 1.5 Rz/μm to about 25 Rz/μm.
8. The method of claim 7 , wherein the surface roughness is from about 3 Rz/μm to about 25 Rz/μm.
9. The method of claim 1 , wherein providing the precursor comprises coating a mixture on the current collector and drying the mixture.
10. The method of claim 1 , wherein heating the precursor and the current collector comprises heating at a temperature from about 300° C. to about 900° C.
11. The method of claim 10 , wherein the temperature is from about 650° C. to about 900° C.
12. The method of claim 1 , wherein heating the precursor and the current collector comprises forming at least one second phase within the composite material.
13. The method of claim 12 , wherein providing the precursor comprises providing metal particles of a second metal within the precursor.
14. The method of claim 13 , wherein the metal particles comprise copper, nickel, iron, titanium, molybdenum, stainless steel, chromium, aluminum, or a combination thereof.
15. The method of claim 14 , wherein the at least one second phase comprises a compound of the second metal and the electrochemically active material.
16. The method of claim 14 , wherein the compound is configured to bind electrochemically active particles of the electrochemically active material together.
17. The method of claim 14 , wherein the at least one second phase comprises a metal silicide.
18. The method of claim 17 , wherein the metal silicide comprises copper silicide, nickel silicide, chromium silicide, aluminum silicide, titanium silicide, or a combination thereof.
19. The method of claim 1 , wherein the composite material comprises from greater than 0% to about 95% by weight of one or more types of carbon phases.
20. The method of claim 19 , wherein the electrochemically active material comprises silicon particles.
21. The method of claim 20 , wherein heating the precursor and the current collector further comprises forming a metal silicide phase configured to bind the silicon particles together and/or the silicon particles to the one or more types of carbon phases.
22. The method of claim 21 , wherein the metal silicide phase comprises copper silicide, nickel silicide, chromium silicide, aluminum silicide, titanium silicide, or a combination thereof.
23. The method of claim 1 , wherein the electrochemically active material comprises silicon particles from about 50% to about 99% by weight.
24. The method of claim 23 , wherein the electrochemically active material comprises the silicon particles from about 60% to about 99% by weight.
25. The method of claim 24 , wherein the electrochemically active material comprises the silicon particles from about 70% to about 99% by weight.