Spherical silicon/graphite/carbon composites as anode material for lithium-ion batteries

• Published in: Journal of power sources 2008-01, Vol.176 (1), p.353-358
• Main Authors: Lee, Jong-Hyuk, Kim, Wan-Jun, Kim, Jae-Youn, Lim, Sung-Hwan, Lee, Sung-Man
• Format: Article
• Language: English
• Subjects: Anode material; Applied sciences; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrochemical performance; Exact sciences and technology; Lithium-ion battery; Silicon/graphite/carbon composite; Specific capacity; Spherical composite
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2007.09.119

A spherical nanostructured Si/graphite/carbon composite is synthesized by pelletizing a mixture of nano-Si/graphite/petroleum pitch powders, followed by heat treatment at 1000 °C under an argon atmosphere. The structure of the composite sphere is examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDAX). The resultant composite sphere consists of nanosized silicon and flaked graphite embedded in a carbon matrix pyrolyzed from petroleum pitch, in which the flaked graphite sheets are concentrically distributed in a parallel orientation. The composite material exhibits good electrochemical properties, a high reversible specific capacity of ∼700 mAh g −1, a high coulombic efficiency of 86% on the first cycle, and a stable capacity retention. The enhanced electrochemical performance is attributed to the structural stability of the composite sphere during the charging–discharging process.