Disclosed herein are a polyimide film for graphite sheets, a method of fabricating the same, and a graphite sheet fabricated using the same. The polyimide film is fabricated by imidizing a polyamic acid formed by reaction between a dianhydride monomer and a diamine monomer, wherein the reaction is carried out in the presence of particles of a metal compound having an average particle diameter (D.sub.50) of about 1 μm to about 6 μm.

A method for preparing artificial graphite, including the steps of: pulverizing a carbonaceous material; carrying out a first deferrization to remove magnetic foreign materials generated by pulverizing the carbonaceous material to form a first deferrization product; granulating the first deferrization product of the first deferrization step to form a granulated product; graphitizing the granulated product to form a graphitized product; and carrying out a second deferrization on the graphitized product to remove magnetic foreign materials from the graphitized product to form the artificial graphite. A negative electrode including the artificial graphite and a lithium secondary battery including the negative electrode are also disclosed.

A process for producing graphite in a vertical graphitization furnace having at least one process chamber that bounds a heating zone, a temperature of 2200° C. to 3200° C. is generated in the heating zone, particulate graphitizable material is supplied to the process chamber through an inlet, graphitizable material is conveyed through the heating zone of the process chamber, in which it is graphitized to graphite, and graphite obtained is removed from the process chamber through an outlet. In some variants, graphitizable material wherein the particles have a particle size of less than 3 mm is used, and/or, a material column is formed throughout the heating zone of a particular process chamber, wherein graphitizable material, after being supplied through the inlet from the top, trickles through an intake zone of the process chamber onto the material column, and/or, a material column is formed in a stationary heating zone of a particular process chamber encompassed by the heating zone, wherein graphitizable material, after being supplied through the intake from the top, trickles through a drop heating zone likewise encompassed by the heating zone onto the material column, and/or, graphitizable material in one or more material vessels is conveyed through a particular process chamber and through the heating zone thereof. Also specified is a vertical graphitization furnace optimized.

A process for producing graphite in a vertical graphitization furnace having at least one process chamber that bounds a heating zone, a temperature of 2200° C. to 3200° C. is generated in the heating zone, particulate graphitizable material is supplied to the process chamber through an inlet, graphitizable material is conveyed through the heating zone of the process chamber, in which it is graphitized to graphite, and graphite obtained is removed from the process chamber through an outlet. In some variants, graphitizable material wherein the particles have a particle size of less than 3 mm is used, and/or, a material column is formed throughout the heating zone of a particular process chamber, wherein graphitizable material, after being supplied through the inlet from the top, trickles through an intake zone of the process chamber onto the material column, and/or, a material column is formed in a stationary heating zone of a particular process chamber encompassed by the heating zone, wherein graphitizable material, after being supplied through the intake from the top, trickles through a drop heating zone likewise encompassed by the heating zone onto the material column, and/or, graphitizable material in one or more material vessels is conveyed through a particular process chamber and through the heating zone thereof. Also specified is a vertical graphitization furnace optimized.

A negative electrode active material including natural graphite. The negative electrode active material has a ratio of D.sub.90 to D.sub.10, which is D.sub.90/D.sub.10, of 2.0 to 2.2, a tap density of 1.11 g/cm.sup.3 to 1.19 g/cm.sup.3, and a BET specific surface area of 2.02 m.sup.2/g to 2.30 m.sup.2/g.

A negative electrode active material including natural graphite. The negative electrode active material has a ratio of D.sub.90 to D.sub.10, which is D.sub.90/D.sub.10, of 2.0 to 2.2, a tap density of 1.11 g/cm.sup.3 to 1.19 g/cm.sup.3, and a BET specific surface area of 2.02 m.sup.2/g to 2.30 m.sup.2/g.

In accordance with the present invention, there is provided a process for producing hydrogen and graphitic carbon from a hydrocarbon gas comprising: contacting at a temperature between 600° C. and 1000° C. the catalyst with the hydrocarbon gas to catalytically convert at least a portion of the hydrocarbon gas to hydrogen and graphitic carbon, wherein the catalyst is a low grade iron oxide.

In accordance with the present invention, there is provided a process for producing hydrogen and graphitic carbon from a hydrocarbon gas comprising: contacting at a temperature between 600° C. and 1000° C. the catalyst with the hydrocarbon gas to catalytically convert at least a portion of the hydrocarbon gas to hydrogen and graphitic carbon, wherein the catalyst is a low grade iron oxide.

The disclosure relates to a carbon-based electrode material that has been graphitized to hold ions in the electrode of a battery and more particularly include carbide or carbide and nitride surfaces that protect the graphite core. The preferred batteries include metal ion such as lithium ion batteries where the carbon-based electrode is the anode although the carbon-based electrode may also serve in dual ion batteries where both electrodes may comprise the graphitized carbon-based electrodes. The electrodes are more amorphous than conventional graphite electrodes and include a carbide or nitride containing surface treatment.

Disclosed herein are dendritically porous three-dimensional structures, including hierarchical dendritically porous three-dimensional structures. The structures include metal foams and graphite structures, and are useful in energy storage devices as well as chemical catalysis.