Silicon-carbonaceous encapsulated materials
A process includes preparing a solution including a silicon precursor or mixture of silicon precursors and a monomer or mixture of monomers; polymerizing the monomer to form a polymer-silicon precursor matrix; and pyrolyzing the polymer-silicon precursor matrix to form an electrochemically active carbon-coated silicon material.
1. A process of forming an electrochemically active material, the process comprising:
preparing a solution comprising:
a silicon precursor or mixture of silicon precursors; and
a monomer or mixture of monomers;
polymerizing the monomer to form a polymer-silicon precursor matrix; and
pyrolyzing the polymer-silicon precursor matrix to form an electrochemically active carbon-coated silicon material which is a compound of formula SiO 2 C or SiO x C, wherein x is less than 2 and greater than 0;
wherein: the monomer or mixture of monomers comprises phenol, urea, benzene-1,3-diol, benzene-1,2-diol, benzene-1,4-diol, methylene phenyl diisocyanates, styrene, methyl methacrylate, vinyl chloride, vinyl fluoride, toluene diisocyanate, melamine, or formaldehyde.
2. The process of claim 1 , wherein silicon precursor comprises a soluble silicon containing material.
3. The process of claim 1 , wherein the silicon precursor comprises silicon acetate, silicon ethoxide, silicon propoxide, or silicon isopropoxide.
4. The process of claim 1 , wherein the polymerizing comprises heating the solution to a temperature sufficient to polymerize the monomer or mixture of monomers.
5. The process of claim 4 , wherein the temperature is from about 25° C. to about 150° C.
6. The process of claim 1 , wherein the pyrolyzing comprising heating the polymer-silicon precursor matrix to a temperature sufficient to degrade the polymer and silicon precursor to the electrochemically active, carbon-coated silicon material.
7. The process of claim 6 , wherein the temperature is from about 400° C. to about 1600° C.
8. The process of claim 1 , wherein the pyrolyzing is conducted under a reducing atmosphere.
9. The process of claim 8 , wherein the reducing atmosphere comprises a reducing gas comprising hydrogen, carbon dioxide, carbon monoxide, acetylene, butane, 1,3-butadiene, 1-butene, cis-2-butene, trans-2-butene, 2-2 dimethylpropane, ethane, ethylene, isobutane, isobutylene, methane, propane, toluene, or propylene.
10. The process of claim 1 , wherein the silicon precursor comprises silicon acetate, silicon ethoxide, silicon propoxide, or silicon isopropoxides; and the monomer or mixture of monomers comprises phenol, urea, benzene-1,3-diol, benzene-1,2-diol, benzene-1,4-diol, methylene phenyl diisocyanates, styrene, methyl methacrylate, vinyl chloride, vinyl fluoride, toluene diisocyanate, melamine, or formaldehyde.