1Myongji University 2Myongji University 3Myongji University 4Myongji University
Carbon/silicon composites were synthesized by mixing silicon powders with petroleum pitch and subsequent heat-treatment. The resultant composites were composed of carbon and nano-size crystalline silicon identified by XRD andEDX. FIB images and SEM images were taken respectively to detect the existence of silicon impregnated in carbonand the distribution of silicon on the carbon surface. The obtained carbon/silicon materials were assembled as half cellanodes for lithium ion secondary battery and their electrochemical properties were tested. The pitch/silicon compositeoC and mixed with 55.5 wt.% of graphite showed relatively good electrochemicalproperties such as the initial efficiency of 78%, the initial discharge capacity of 605 mAh/g, and the discharge capacityof 500 mAh/g after 20 cycles.