Silicon material and method of manufacture

Abstract

A method for manufacturing a silicon material can include comminuting a silicon material. A silicon material can include silicon nanoparticles formed by comminuting silicon particles, where the silicon nanoparticles can cooperatively form pores.

We claim: 
     
         1 . A silicon material comprising:
 silicon nanoparticles with a mean size between about 50-200 nm, wherein the silicon nanoparticles are spheroidal, wherein the silicon nanoparticles comprise 3-37% oxygen by mass, wherein the silicon nanoparticles are formed by comminuting silicon particles comprising at least 99% silicon by mass.   
     
     
         2 . The silicon material of  claim 1 , wherein a surface of a silicon nanoparticle is fused to a surface of adjacent silicon nanoparticles. 
     
     
         3 . The silicon material of  claim 2 , wherein the silicon nanoparticles cooperatively define a void space between adjacent silicon nanoparticles. 
     
     
         4 . The silicon material of  claim 3 , wherein a characteristic dimension of the void space is between 0.5 and 500 nm. 
     
     
         5 . The silicon material of  claim 1 , wherein the silicon nanoparticles are nonporous. 
     
     
         6 . The silicon material of  claim 1 , further comprising a graphitic coating disposed on the silicon nanoparticles with a thickness between 1-10 nm. 
     
     
         7 . The silicon material of  claim 1 , wherein the silicon nanoparticles comprise a 1-5 nm thick surface layer of silicon oxide. 
     
     
         8 . The silicon material of  claim 1 , further comprising a polymer coating disposed on the silicon nanoparticles. 
     
     
         9 . The silicon material of  claim 8 , wherein the polymer coating comprises at least one of: polytetrafluoroethylene, polyvinylidene fluoride, polyacrylic acid, carboxymethyl cellulose, styrene-butadiene rubber, polyacrylonitrile, alginate, polyimide, polyamide, polyaniline, polypyrrole, poly(thiophene), or poly(3,4-ethylenedioxythiophene). 
     
     
         10 . The silicon material of  claim 1 , wherein a size distribution of the silicon nanoparticles is a mollified uniform distribution. 
     
     
         11 . A method for manufacturing a silicon material comprising:
 reducing a silica precursor to produce silicon particles comprising at least 99% silicon by mass, wherein a mean characteristic size of the silicon particles is between about 2 μm and 50 μm; and   comminuting the silicon particles to prepare comminuted silicon particles with a mean characteristic size between about 50-200 nm.   
     
     
         12 . The method of  claim 11 , wherein the silicon particles are spheroidal. 
     
     
         13 . The method of  claim 12 , wherein the comminuted silicon particles are spheroidal. 
     
     
         14 . The method of  claim 11 , wherein comminuting the silicon particles comprises continuously ball milling the silicon particles for between 1 and 12 hours. 
     
     
         15 . The method of  claim 14 , wherein the silicon particles are ball milled at a speed between 100 and 600 rpm. 
     
     
         16 . The method of  claim 11 , further comprising oxidizing the comminuted silicon particles, wherein the comminuted silicon particles comprise 3-37% oxygen by mass. 
     
     
         17 . The method of  claim 16 , wherein oxidizing the comminuted silicon comprises heating the comminuted silicon particles in an oxidizing environment to a temperature between 200-1000° C. for 1-24 hours. 
     
     
         18 . The method of  claim 11 , further comprising coating the comminuted silicon particles with a carbonaceous material. 
     
     
         19 . The method of  claim 18 , wherein coating the comminuted silicon particles comprises growing the carbonaceous material on the comminuted silicon particles using chemical vapor deposition. 
     
     
         20 . The method of  claim 19 , wherein growing the carbon carbonaceous material comprises:
 heating the comminuted silicon particles to a temperature between 700-950° C. under an inert gas flow rate between 50 and 500 sccm and a hydrogen gas flow rate between 20 and 100 sccm;   further heating the comminuted silicon particles to a temperature between 900 and 1100° C. and introducing at least one of methane or ethyne at a flow rate between 20 and 200 sccm, where the at least one of methane or ethyne is introduced for between 5 minutes and 2 hours.