Process For The Production Of Highly Graphitizable Carbon Foam
A highly graphitizable carbon foam useful for, inter alia, battery components or high temperature applications, which includes a carbon foam produced from conventional mesophase pitch and a cross-linking agent like sulfur.
1 . A method for preparing a highly graphitizable carbon foam, comprising:
a. combining mesophase pitch and a cross-lining agent to form a cross-linking agent-mesophase pitch mixture; and
b. treating the cross-linking agent-mesophase pitch mixture to form a graphitizable carbon foam.
2 . The method of claim 1 wherein the cross-linking agent is selected from the group consisting of sulfur, quinone, oxidizing agents, inorganic carbenes, and mixtures thereof.
3 . The method of claim 2 wherein the cross-linking agent comprises (NH 4 ) 2 S 2 O 3 , NaClO 3 , oxygen, chlorates, dichromates, persulfates, or mixtures thereof.
4 . The method of claim 2 wherein the cross-linking agent comprises SnCl 2 and PbCl 2 , or mixtures thereof.
5 . The method of claim 2 wherein the cross-linking agent comprises sulfur.
6 . The method of claim 5 wherein step b) further comprises the steps of:
b1) pressurizing the sulfur-mesophase pitch mixture to form a pressurized sulfur-mesophase pitch mixture;
b2) heating the pressurized sulfur-mesophase pitch mixture to a temperature of from about 450° C. to about 690° C. to form a heated, pressurized sulfur-mesophase pitch mixture;
b3) baking the green foam to form the graphitizable carbon foam.
7 . The method of claim 5 wherein step b) further comprises the steps of:
b1) heating the pressurized sulfur-mesophase pitch mixture at atmospheric pressure to a temperature of from about 450° C. to about 690° C. to form a heated sulfur-mesophase pitch mixture;
b2) baking the green foam to form the graphitizable carbon foam.
8 . The method of claim 1 wherein the mesophase component of the pitch comprises of from about 60% to about 100% of the pitch.
9 . The method of claim 8 wherein the mesophase component of the pitch comprises of from about 90% to about 100% of the pitch.
10 . The method of claim 1 wherein the mesophase pitch is derived from coal tar.
11 . The method of claim 1 wherein the mesophase pitch is derived from petroleum.
12 . The method of claim 5 wherein the sulfur-mesophase pitch mixture comprises of from about 1% to about 10% sulfur.
13 . The method of claim 12 wherein the sulfur-mesophase pitch mixture comprises of from about 4% to about 6% sulfur.
14 . The method of claim 1 wherein in step b) the sulfur-mesophase pitch mixture is pressurized to a pressure of no greater than about 500 psi.
15 . The method of claim 14 wherein the sulfur-mesophase pitch mixture is pressurized to a pressure of at from about 30 psi to about 100 psi.
16 . A method for preparing a graphite foam, comprising:
a. combining mesophase pitch and sulfur to form a sulfur-mesophase pitch mixture;
b. treating the sulfur-mesophase pitch mixture to form a graphitizable foam; and
c. heating the graphitizable carbon foam to create conductive graphite foam.
17 . The method of claim 16 wherein step c) comprises baking the graphitizable carbon foam at a temperature of from about 2800° C. to about 3100° C.
18 . The method of claim 16 wherein the conductive graphite foam of step c) comprises an interlayer spacing of from about 3.354 Angstroms to about 3.365 Angstroms.