Decomposition of silicon-containing precursors on porous scaffold materials
Composites of silicon and various porous scaffold materials, such as carbon material comprising micro-, meso- and/or macropores, and methods for manufacturing the same are provided. The compositions find utility in various applications, including electrical energy storage electrodes and devices comprising the same.
1. A method for producing a composite material comprising a porous carbon scaffold and silicon, comprising the following steps:
a. mixing polymer precursors and storing the resulting mixture for a period of time at sufficient temperature to allow for polymerization of the precursors to form a polymer material;
b. carbonizing the resulting polymer material to create a porous carbon material;
c. subjecting the porous carbon material to elevated temperature in a reaction vessel in the presence of a silicon-containing precursor and a hydrocarbon material that decomposes at a higher temperature than the silicon containing precursor;
d. elevating the temperature to between 300° C. and 500° C. to decompose the silicon containing precursor, thereby impregnating silicon into pores of the porous carbon material, resulting in a silicon impregnated carbon material; and
e. further elevating the temperature to decompose the hydrocarbon material, resulting in a carbon-coated, silicon impregnated carbon material,
wherein the impregnating of the silicon into the pores of the porous carbon material reduces a pore volume of the silicon impregnated carbon material relative to a pore volume of the porous carbon material.
2. The method of claim 1 , wherein the silicon is impregnated into the pores of the porous carbon material by processing in a reactor at a temperature between 400° C. and 500° C. in the presence of a silicon-containing gas.
3. The method of claim 1 , wherein the silicon is impregnated into the pores of the porous carbon material by processing in a reactor at a temperature between 450° C. and 500° C. in the presence of silane.
4. The method of claim 1 , wherein the silicon containing precursor is silane, disilane, trisilane, tetrasilane, or a combination thereof.
5. The method of claim 1 , wherein the hydrocarbon material is methane, ethane, propane, butane, pentane, heptane, hexane, cyclohexane, octane, nonane or decane, or a combination thereof.
6. The method of claim 1 , wherein the reaction vessel pressure is below atmospheric pressure.
7. The method of claim 1 , wherein the reaction vessel pressure is at atmospheric pressure.
8. The method of claim 1 , wherein the reaction vessel pressure is above atmospheric pressure.
9. The method of claim 1 , wherein at one or more steps the reaction vessel pressure and temperature are such that the silicon containing precursor is in the supercritical state.
10. The method of claim 1 , wherein at one or more of steps c, d and e, the reaction vessel pressure and temperature are such that the hydrocarbon material is in the supercritical state.
11. The method of claim 1 , wherein the reaction vessel is a tube furnace, fluid bed reactor, rotary kiln reactor, elevator kiln, or roller hearth kiln.
12. The method of claim 1 , wherein the reaction vessel comprises a batch reactor, continuous stirred-tank reactor, plug flow reactor, semi-batch reactor, packed bed reactor, oscillatory baffled reactor, membrane reactor, or tubular reactor.
13. The method of claim 1 , further comprising contacting the porous carbon material with a catalyst prior to contacting the porous carbon material with the silicon-containing precursor.
14. The method of claim 13 , wherein the catalyst is aluminum, nickel or manganese, or combinations thereof.
15. The method of claim 1 , wherein silicon embedded within the porous carbon material occupies between 20% and 80% of the total available pore volume within the porous carbon material.
16. The method of claim 1 , wherein greater than 95% of the total pore volume of the porous carbon material resides in pores having a diameter of 1 nm or less.