Surface Structures and Charge-Discharge Characteristics of Mesocarbon Microbeads as the Anodes for Secondary Lithium-Ion Batteries

The effect of the surface structure of mesocarbon microbeadson charge-discharge characteristics as anodes for secondary lithium-ion batteries was investigated. SEM (Scanning Electron Microscope) and Raman spectroscopy suggested that the mesocarbon microbeads had a more highly graphitized carbon layer on the surface than the inner carbons. The carbon layer caused the small capacity or the short cycle life as the anode. The heat-treatment of the mesocarbon microbeads in air for removing the surface layer gave a good effect on the capacity and the charge-discharge cycle for the anode.