A
graphite powder has surface closed-end structures in which the
graphite c-plane
layers of the
graphite layer
crystal lattices have closed-ends on the surface of the graphite
powder by linking the ends of one or more pairs of the c-plane
layers, leaving interstices which are open on the surface of the graphite. The number of open interstices is at least 100 and at most 1500 per
micrometer in a c-axis direction of the graphite. Preferably, the graphite
powder has a specific surface area of 1.0 m2 / g or less. Such a graphite powder can be prepared either by graphitizing a carbon material, which has been pulverized at a high speed under well-controlled conditions before and / or after the
carbonization, or by subjecting a carbon material, which has been pulverized under well-controlled conditions before and / or after the
carbonization, to graphitization and then to oxidative heat treatment at a temperature of 600-800° C. and finally to heat treatment at a temperature of 800° C. or higher in an
inert gas. The graphite powder can be used to produce negative electrodes of
lithium ion secondary batteries having a high
discharge capacity of at least 320 mAh / g and a high charge /
discharge coulombic efficiency of at least 90%.