Substantially pure bulk pyrocarbon and methods of preparation

Abstract

The present invention provides a substantially pure and finely divided granular pyrolytic carbon material. The substantially pure pyrolytic carbon can be used in a variety of applications including filtration and battery electrode applications. The present invention further describes a process for producing a substantially pure pyrolytic carbon material that includes heating a mixture of refractory inorganic particles with a hydrocarbon gas for an amount of time sufficient to deposit a substantially uniform layer of pyrolytic carbon on the surfaces of the particles.

1 . A substantially pure and finely divided bulk pyrolytic carbon comprising: 
 inorganic particles having a surface area of at least 10 m 2 /g; and    a substantially uniform layer of carbon on the surface of said inorganic particles, wherein said layer of carbon is deposited to a thickness of at least about five times greater than the smallest dimension of said particles.    
     
     
         2 . The substantially pure and finely divided bulk pyrolytic carbon of  claim 1 , wherein said surface area of said inorganic particles is greater than about 50 m 2 /g.  
     
     
         3 . The substantially pure and finely divided bulk pyrolytic carbon of  claim 1 , wherein the diameter of said inorganic particles is less than about 1 micron.  
     
     
         4 . The substantially pure and finely divided bulk pyrolytic carbon of  claim 1 , wherein the length of said inorganic particles is from about 3 to about 5000 microns.  
     
     
         5 . The substantially pure and finely divided bulk pyrolytic carbon of  claim 1 , wherein said layer of carbon is deposited to a thickness of at least about ten times greater than the smallest dimension of said particles.  
     
     
         6 . The substantially pure and finely divided bulk pyrolytic carbon of  claim 1 , wherein said inorganic particles are selected from the group consisting of carbon particles and ceramic particles.  
     
     
         7 . The substantially pure and finely divided bulk pyrolytic carbon of  claim 6 , wherein said inorganic particles are carbon particles.  
     
     
         8 . The substantially pure and finely divided bulk pyrolytic carbon of  claim 7 , wherein the carbon particles are selected from the group consisting of powders, particulates, whiskers, and flakes.  
     
     
         9 . The substantially pure and finely divided bulk pyrolytic carbon of  claim 8 , wherein said carbon particles are carbon whiskers.  
     
     
         10 . The substantially pure and finely divided bulk pyrolytic carbon of  claim 9 , wherein said carbon whiskers are selected from the group consisting of vapor grown carbon whiskers and carbonized polymeric nanofibers.  
     
     
         11 . The substantially pure and finely divided bulk pyrolytic carbon of  claim 9 , wherein said carbon whiskers have a diameter less than about 1 micron.  
     
     
         12 . The substantially pure and finely divided bulk pyrolytic carbon of  claim 6 , wherein said inorganic particles are ceramic particles.  
     
     
         13 . The substantially pure and finely divided bulk pyrolytic carbon of  claim 12 , wherein said ceramic particles are selected from the group consisting of powders, particulates, whiskers, and flakes.  
     
     
         14 . The substantially pure and finely divided bulk pyrolytic carbon of  claim 13 , wherein said ceramic particles are ceramic whiskers selected from the group consisting of alumina, silica, silicon carbide, silicon nitride, titanium carbide, titanium nitride, zirconia, ceria, and glass whiskers.  
     
     
         15 . The substantially pure and finely divided bulk pyrolytic carbon of  claim 1 , wherein a particle of said pyrolytic carbon has at least one dimension less than about 10 microns.  
     
     
         16 . The substantially pure and finely divided bulk pyrolytic carbon of  claim 15 , wherein a particle of said pyrolytic carbon has at least one dimension less than about 3 microns.  
     
     
         17 . The substantially pure and finely divided bulk pyrolytic carbon of  claim 1 , wherein said pyrolytic carbon is 99 weight percent carbon.  
     
     
         18 . The substantially pure and finely divided bulk pyrolytic carbon of  claim 1 , wherein said pyrolytic carbon is 95 weight percent carbon.  
     
     
         19 . The substantially pure and finely divided bulk pyrolytic carbon of  claim 1 , wherein said pyrolytic carbon has a microstructure selected from the group consisting of rough laminar, smooth laminar and isotropic microstructures.  
     
     
         20 . The substantially pure and finely divided bulk pyrolytic carbon of  claim 1 , wherein said carbon is amorphous.  
     
     
         21 . A filler comprising the substantially pure pyrolytic carbon of  claim 1 .  
     
     
         22 . A thermoplastic composition comprising the filler of  claim 21 .  
     
     
         23 . An electrode comprising the filler of  claim 21.