NEGATIVE ACTIVE MATERIAL USED FOR SECONDARY BATTERY, ELECTRODE OF SECONDARY BATTERY AND SECONDARY BATTERY INCLUDING THE SAME

摘要

PURPOSE: A negative active material for secondary batteries is provided to improve capacity retention rate, and the discharge capacity and efficiency of secondary batteries. CONSTITUTION: A negative active material for secondary batteries comprises a core carbon material whose some edge or whole surface is covered with a carbide layer. When the negative active material is compressed by the pressure of 1.3ton/1cm^2 for 2 seconds, the ratio of specific surface area and sphericity index before and after the compression are 1.6 or less and 0.6 or greater respectively. The core carbon material is highly crystallized spherical natural graphite.