A silicon material can include a composition with at least about 50% silicon, at most about 45% carbon, and at most about 10% oxygen. The silicon material can have an external expansion that is less than about 40%. The silicon material can include silicon nanoparticles, which can cooperatively form clusters. The silicon nanoparticles can be porous.

The invention provides liquid compositions comprising conductive carbon particles and/or carbon nanoparticles, a thickening agent, and a solvent. The carbon nanoparticles are preferably a mixture of graphite nanoplatelets and carbon nanotubes and the thickening agent is preferably a cellulose derivative. The liquid compositions can be used as ink to print highly conductive films that adhere to paper substrates.

In order to provide a thermal transport structure excellent in bendability, heat dissipation property, and lightweight property and also a thermal transport structure having a high reliability against vibrations and an excellent heat transport performance, used is a thermal transport structure (5, 201) including stacked graphite sheets (1, 213). This thermal transport structure (5, 201) includes a fixing portion (10, 202, 301) in which the stacked graphite sheets (1, 213) are fixed to each other;

and a thermally conductive portion (11, 203) in which the stacked graphite sheets (1, 213) are not fixed to each other.

A flexible graphite sheet support structure forms a thermal management arrangement for device having a heat source. The flexible graphite sheet support structure includes first and second spaced apart support members and a flexible graphite sheet secured to the spaced apart support members forming a free standing flex accommodating section that spans between them. Curve retention members having convex curved surfaces are used to keep the flex accommodating section in a bell shaped curve while preventing the flexible graphite sheet from exceeding a minimum bend radius. The thermal management arrangement formed by the flexible graphite sheet support structure enables the flexible graphite sheet to move heat from one support structure to the other while reducing the transmission of vibration between them and allowing relative movement between the spaced apart support structures.

A negative active material includes a carbon material. The carbon material satisfies the following relationship: 6<Gr/K<16, Gr is a graphitization degree of the carbon material, measured by means of X-ray diffraction; and K is a ratio Id/Ig of a peak intensity Id of the carbon material at a wavenumber of 1250 cm.sup.−1 to 1650 cm.sup.−1 to a peak intensity Ig of the carbon material at a wavenumber of 1500 cm.sup.−1 to 1650 cm.sup.−1, and is measured by using Raman spectroscopy, and K is 0.06 to 0.15. The negative active material according to this application can significantly improve an energy density, cycle performance, and rate performance of the electrochemical device.

A negative active material includes a carbon material. The carbon material satisfies the following relationship: 6<Gr/K<16, Gr is a graphitization degree of the carbon material, measured by means of X-ray diffraction; and K is a ratio Id/Ig of a peak intensity Id of the carbon material at a wavenumber of 1250 cm.sup.−1 to 1650 cm.sup.−1 to a peak intensity Ig of the carbon material at a wavenumber of 1500 cm.sup.−1 to 1650 cm.sup.−1, and is measured by using Raman spectroscopy, and K is 0.06 to 0.15. The negative active material according to this application can significantly improve an energy density, cycle performance, and rate performance of the electrochemical device.

A graphite membrane includes graphene layers, wherein the graphite membrane is an independent graphite membrane having a thickness of 10 nm to 12 μm, an area of 5×5 mm.sup.2 or more, an electrical conductivity of 8000 S/cm or more, and an arithmetic average roughness Ra of 200 nm or less on a surface of the graphite membrane.

A graphite membrane includes graphene layers, wherein the graphite membrane is an independent graphite membrane having a thickness of 10 nm to 12 μm, an area of 5×5 mm.sup.2 or more, an electrical conductivity of 8000 S/cm or more, and an arithmetic average roughness Ra of 200 nm or less on a surface of the graphite membrane.

Disclosed is AA′ graphite with a new stacking feature of graphene, and a fabrication method thereof. Graphene is stacked in the sequence of AA′ where alternate graphene layers exhibiting the AA′ stacking are translated by a half hexagon (1.23 Å). AA′ graphite has an interplanar spacing of about 3.44 Å larger than that of the conventional AB stacked graphite (3.35 Å) that has been known as the only crystal of pure graphite. This may allow the AA′ stacked graphite to have unique physical and chemical characteristics.

A film includes a film body including graphite, and at least one fragment including graphite and formed on one or more surfaces of the film body. The film has a water contact angle of 50 degrees or greater and a glossiness of 20 or lower.