NOVELTY - A negative active material comprises spherically-shaped natural graphite-modified composite particles (100) comprising spherically-shaped natural graphite particle in which flake-shaped natural graphite fragments (10) build up and assemble into cabbage or random shape, and amorphous or semi-crystalline carbon (30), in which open gap (20) between flake-shaped natural graphite fragments is positioned on surface and inside spherically-shaped natural graphite particle, and amorphous or semi-crystalline carbon is coated on surface of spherically-shaped natural graphite particles.    USE - Negative active material is used for rechargeable lithium battery (claimed).    ADVANTAGE - The negative active material provides rechargeable lithium battery having excellent charging-discharging characteristics and cycle-life characteristics.    DETAILED DESCRIPTION - A negative active material comprises spherically-shaped natural graphite-modified composite particles comprising spherically-shaped natural graphite particle in which flake-shaped natural graphite fragments build up and assemble into cabbage or random shape, and amorphous or semi-crystalline carbon, in which an open gap between the flake-shaped natural graphite fragments is positioned on surface portion and inside the spherically-shaped natural graphite particle, and the amorphous or semi-crystalline carbon is coated on the surface of the spherically-shaped natural graphite particles, and the amorphous or semi-crystalline carbon is present in the open gap, and thereby the open gap positioned on the surface portion and inside the spherically-shaped natural graphite particle is maintained. INDEPENDENT CLAIMS are included for the following:    (1) preparation of negative active material, which involves preparing a solution comprising spherically-shaped natural graphite particles, amorphous or semi-crystalline carbon precursor, and solvent, performing ultrasonication on the solution, opening between the flake-shaped natural graphite fragments of surface portion and inside the spherically-shaped natural graphite particle to form an open gap while maintaining crystallinity of the spherically-shaped natural graphite particle, and simultaneously coating the surface of the spherically-shaped natural graphite particle with the amorphous or semi-crystalline carbon precursor and impregnating the amorphous or semi-crystalline carbon precursor in the open gap present on the surface portion and inside the spherically-shaped natural graphite particles, drying the solution subjected to the ultrasonication to obtain spherically-shaped natural graphite-modified particles and heat-treating the spherically-shaped natural graphite-modified particles to prepare spherically-shaped natural graphite-modified composite particles including amorphous or semi-crystalline carbon that is coated on the surface of the spherically-shaped natural graphite particle and that is present in the open gap present on the surface portion and inside the spherically-shaped natural graphite particles; and    (2) rechargeable lithium battery, which comprises negative electrode including the negative active material, positive electrode and electrolyte solution.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of negative active material.    Flake-shaped natural graphite fragments (10)    Open gap (20)    Amorphous or semi-crystalline carbon (30)    Spherically-shaped natural graphite modify composite particles (100)