The influence of the graphitic structure on the electrochemical characteristics for the anode of secondary lithium batteries

Carbon is one of the best candidate materials for the negative electrode of rechargeable lithium battieres, however, the electrochemical characteristics are not fully understood in terms of the structure of the materials. The relationship linking the volume ration of the graphitic structures (P sub 1 ) of mesocarbon microbeads (MCMBs) and the electrochemical characteristics has been examined, and it was found that the capacity in the range between 0-0.25 V (vs. Li/Li exp + ) in 1 moldm exp -3 LiClO sub 4 /ethylene carbonate (EC)+1,2-diethoxyethance (DEE) electrolyte increased with an increase of the P sub 1 of the MCMBs. This result shows that the Li storage mechanism of this potential range is the Li-intercalation reaction into the graphitic layers with the AB or ABC stacking. On the other hand, MCMB heat-treatment temperature (HTT) 1000 deg C showed much larger capacity in the range between 0.25-1.3 V than higher HTT MCMBs, and it is suggested the interaction among each graphite layer is weaker in nongraphitized carbon than that in well-graphitized ones.