PREPARATION AND CHARACTERIZATION OF HIGH-POWER ANODE MATERIALS USING SOFT CARBON/GRAPHITE COMPOSITES FOR LITHIUM ION SECONDARY BATTERY

摘要

The high-power anode materials for Lithium (Li) ion secondary battery were investigated by using various carbon materials such as cokes, graphite and petroleum pitch which were prepared by milling, pitch coating, and subsequent heat treatment at different composites weight ratios. After the heat treatment of pitch/cokes composites at 1000°C, the obtained discharge capacities were not much different with various weight ratios. Although a relatively high average discharge capacity was attained for pitch/graphite composite at 1:1 weight ratio, it was considered to be unsuitable for being used as a high-power anode material of Li ion secondary batteries due to the fact that the plateau characteristics was appeared at 0.2 ～ 05 V range in the voltage-capacity curve of the composite. When the heat treatment temperature for various soft carbon/graphite composites was decreased to 800 °C, the power capabilities and initial efficiencies of the composites with pitch/cokes weight ratio at 1:4 were improved significantly. A high reversible capacity around 500 mAh/g was obtained for the soft carbon/graphite composites with pitch/cokes weight ratios at 1:1 and 4:1, despite of showing relatively low power capabilities and initial efficiencies.