Composition of matter for the production of graphite powder

Abstract

The present invention relates to a composition for the production of a graphite powder, suitable for making high performance lithium-ion battery anodes and other applications. The composition of matter comprises a biochar, a metal and graphite. The biochar is typically derived from the pyrolysis of woody biomass. The metal is typically a transition metal derived from the decomposition and reduction of an organic or inorganic metallic compound. The graphite is highly crystalline and has a wide range of morphologies or structures.

What is claimed is: 
     
         1 . A method of producing a mixture a mixture of biochar, a metal, and graphite, comprising:
 i) thermally treating biomass in particulate form at a temperature of between 200 and 1000 degrees Celsius to form a particulate biochar;   ii) combining the resulting biochar with a particulate metal compound combining the resulting biochar with a particulate metal compound in a wet or a dry form to create a precursor mixture;   iii) heating the precursor mixture to between about 400 to about 3000 degrees Celsius under inert conditions to form a graphite containing mixture;   iv) sieving the final mixture to below about 1 mm particulate size to produce a mixture having (a) a graphite content of between about 25 to 65 percent by weight, (b) a metal content of between about 15 to 75 percent by weight and (c) a biochar content of between 1 and 35 percent by weight.   
     
     
         2 . The method as claimed in  claim 1 , wherein the biomass is thermally treated in water in a hydrothermal step. 
     
     
         3 . The method as claimed in  claim 1 , wherein the biomass is thermally treated under inert conditions in a dry pyrolysis step. 
     
     
         4 . The method as claimed in  claim 1 , wherein the biomass is selected from forestry residue, sawdust, wood chip or other wood-based material. 
     
     
         5 . The method as claimed in  claim 1 , wherein the biomass particles are less than about 10 mm 
     
     
         6 . The method as claimed in  claim 1 , wherein the mixture has a total graphitic carbon content of great than about 55% by weight. 
     
     
         7 . The method as claimed in  claim 1 , wherein the method includes one or more of the following steps, selected from:
 (a) purification;   (b) washing and filtering the resulting graphite;   (c) densification; and   (d) carbon coating.   
     
     
         8 . A graphite powder produced from a method as claimed in  claim 1 . 
     
     
         9 . A high performance lithium ion battery anode powder produced from a method as claimed in  claim 1 .