Electrochemical performance of modified synthetic graphite for lithium ion batteries

The carbon-coated composite ha's been manufactured and investigated as the negative electrode for Li-ion batteries. The carbon-coated composite powders are prepared by a simple mixing of two types of synthetic graphite particles (SFG6 and SFG44) with polyvinylchloride powders and heating to a temperature between 800 and 1100degreesC under an argon gas flow. As a result of the carbon-coating treatment, the flake particles of the original graphites changed into a bulky shape of carbon-coated composite with a largely increased particle size due to aggregation through the treatment. It is shown that carbon-coated composite electrodes for the two types of graphite have much lower irreversible loss than the original graphites and coulombic efficiency of similar to91% in the first cycle in a PC-based electrolyte. The carbon coating treatment improves the cycling performance. Despite their coarse morphology due to aggregation, carbon-coated composite electrodes show the enhanced high rate capabilities. (C) 2005 Springer Science + Business Media, Inc.