NEGATIVE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY, LITHIUM SECONDARY BATTERY COMPRISING THE SAME, AND PREPARING METHOD OF NEGATIVE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERY

摘要

PURPOSE: Provided are carbon material having high charge/discharge capacity and excellent cycle property, a lithium secondary battery containing the carbon material, which has improved energy density and cycle property, and a process for producing the carbon material. CONSTITUTION: The carbon material(1) is produced by the process comprising the steps of: calcining Si particles comprising crystalline silicon in a carbon crucible at 1300-1400deg.C to deposit SiO2 state and SiC state in the crystalline Si state; bonding conductive carbon material to the Si particle and forming a polymer membrane covering the Si particle to prepare a precursor of a composite particle(3) and then calcining the precursor of the composite particle(3) to form a hard carbon membrane by carbonizing the polymer membrane and obtaining the composite particles(3); bonding the Si particles to a graphite particle(2) and forming a polymer membrane covering the graphite particle(2) to prepare a precursor of the carbon material(1) and calcining the precursor of the carbon material(1) to form an amorphous carbon membrane(4) by carbonizing the polymer membrane and obtaining the carbon material(1). The graphite particle(2) has a face distance(d002) of a (002) face by X-ray wide angle diffraction being less than 0.337nm and the amorphous carbon membrane(4) has a d002 of more than 0.37nm. And the lithium secondary battery contains the carbon material(1) as an anode.