Electrochemical cell electrodes comprising coal-based carbon foam
Coal based carbon foams that are produced by the controlled beating of coal particulate in a mold and under a non-oxidizing atmosphere and subsequently graphitized have been found to provide excellent electrode materials for electrochemical cell applications.
1. A fuel cell comprising:
a polymer electrolyte membrane;
an anode;
a cathode; and
appropriate conductors for the supply of electrical current to an electrical load,
wherein at least one of said anode and said cathode comprises a coal-based carbon foam produced from particulate coal of a small diameter and exhibits a density in the range of about 0.1 g/cm 3 to about 0.8 g/cm 3 , a thermal conductivity of below about 1 W/m/° K. and a pore size below about 2000 μm.
2. The fuel cell of claim 1 wherein said small diameter is less than about 1 mm.
3. The fuel cell of claim 1 wherein said coal-based carbon foam has a compressive strength below about 6000 psi.
4. The fuel cell of claim 1 wherein said coal-based carbon foam is prepared from bituminous coal.
5. The fuel cell of claim 4 wherein said bituminous coal has a swell index of between about 3 and about 9.
6. The fuel cell of claim 4 wherein said bituminous coal has a Gieseler plasticity value above about 500 DDPM.
7. The fuel cell of claim 1 wherein said coal-based carbon foam exhibits a pore size below about 100μ.
8. The fuel cell of claim 1 wherein said coal-based carbon foam has been graphitized at a temperature between about 1600° C. and 3000° C.
9. The fuel cell of claim 8 wherein said coal-based carbon foam has been graphitized at a temperature between about 1800° C. and about 2200° C.
10. The fuel cell of claim 9 wherein said coal-based carbon foam has been graphitized at a temperature of about 2200° C.
11. The fuel cell of claim 1 wherein said coal-based carbon foam is prepared by a process comprising the steps of:
comminuting coal to a small particle size to form a ground coal;
placing said ground coal in a mold;
heating said ground coal in said mold under a non-oxidizing atmosphere to a temperature of between about 300° C. and about 700° C. and soaking at this temperature for a period of from about 10 minutes to about 12 hours to form an electrode preform;
controllably cooling said electrode preform; and
graphtizing said electrode preform at a temperature between about 1600° C. and 3000° C.
12. An electrical cell for the generation or storage of electrical power through an electrochemical reaction comprising:
an anode;
a cathode; and
appropriate conductors for the supply of electrical current to an electrical load,
wherein at least one of said anode and said cathode comprises a coal-based carbon foam produced from particulate coal of a small diameter and exhibits a density in the range of about 0.1 g/cm 3 to about 0.8 g/cm 3 , a thermal conductivity of below about 1 W/m/° K, and a pore size below about 2000 μm.
13. The electrical cell of claim 12 wherein said particulate coal has a swell index of between about 3 and about 9.
14. The electrical cell of claim 13 wherein said particulate coal has a swell index of about 4.
15. The electrical cell of claim 12 wherein said particulate coal has a Gieseler plasticity value above about 500 DDPM.
16. The electrical cell of claim 12 wherein said small diameter is less than about 1 mm.
17. The electrical cell of claim 12 wherein said coal-based carbon foam has a compressive strength below about 6000 psi.
18. The electrical cell of claim 12 wherein said coal-based carbon foam exhibits a pore size below about 100 μm.
19. The electrical cell of claim 12 wherein said coal-based carbon foam has been graphitized at a temperature between about 1600° C. and 3000° C.
20. The electrical cell of claim 19 wherein said coal-based carbon foam has been graphitized at a temperature between about 1800° C. and about 2200° C.
21. The electrical cell of claim 20 wherein said coal-based carbon foam has been graphitized at a temperature of about 2200° C.
22. The electrical cell of claim 12 wherein said carbon foam is prepared by a process comprising the steps of:
comminuting coal to a small particle size to form a ground coal;
placing said ground coal in a mold;
heating said ground coal in said mold under a non-oxidizing atmosphere to a temperature of between about 300° C. and about 700° C. and soaking at this temperature for a period of from about 10 minutes to about 12 hours to form an electrode preform;
controllably cooling said electrode preform; and
graphtizing said electrode preform at a temperature between about 1600° C. and 3000° C.
23. A fuel cell comprising:
polymer electrolyte membrane;
an anode;
a cathode; and
appropriate conductors for the supply of electrical current to an electrical load,
wherein at least one of said anode and said cathode comprises a coal-based carbon foam produced produced by the process comprising:
comminuting coal to a small particle size to form a ground coal;
placing said ground coal in a mold;
heating said ground coal in said mold under a non-oxidizing atmosphere to a temperature of between about 300° C. and about 700° C. and soaking at this temperature for a period of from about 10 minutes to about 12 hours to form an electrode preform;
controllably cooling said electrode preform; and
graphtizing said electrode preform at a temperature between about 1600° C. and 3000° C.,
wherein said coal-based carbon foam exhibits a density in the range of about 0.1 g/cm 3 to about 0.8 g/cm 3 , a thermal conductivity of below about 1 W/m/° K, and a pore size below about 2000 μm.
24. An electrical cell for the generation or storage of electrical power through an electrochemical reaction comprising:
an anode;
a cathode; and
appropriate conductors for the supply of electrical current to an electrical load,
wherein at least one of said anode and said cathode comprises a coal-based carbon foam produced by the process comprising:
comminuting coal to a small particle size to form a ground coal;
placing said ground coal in a mold;
heating said ground coal in said mold under a non-oxidizing atmosphere to a temperature of between about 300° C. and about 700°? C and soaking at this temperature for a period of from about 10 minutes to about 12 hours to form an electrode preform;
controllably cooling said electrode preform; and
graphtizing said electrode preform at a temperature between about 1600° C. and 3000° C.,
wherein said carbon based foam exhibits a density in the range of about 0.1 g/cm 3 to about 0.8 g/cm 3 , a thermal conductivity of below about 1 W/m/° K, and a pore size below about 2000 μm.