Mesocarbon microbeads (MCMB) powders were treated in Ar-H2, Ar-N2, Ar-H2-CO2 and Ar-N2-CO2 induction thermal plasmas under reduced pressure of 53 kPa. The plasma treated powders were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and Raman spectroscopy. The plasma treatment did not give rise to the graphitization in the bulk, but gave the modification subjected to the surface morphology, structure and chemical composition. The surface of the Ar-N2 plasma-treated particles was covered by the fine condensate, while the surface morphology of Ar-N2-CO2 plasma-treated particles became rough and had no condensate. Electrochemical measurements as an anode of lithium rechargable battery were performed in 1M LiClO4/(ethylene carbonate [EC] + diethyl carbonate [DEC]). Discharge capacity of the plasma-treated MCMB powders is larger than that of original MCMB powders. Also, first discharge/charge efficiency of the MCMB powders treated in the atmospheres containing CO2 is higher than that of original powders. These results suggest that the modification of the surface structure, morphology and chemical composition by the plasma treatment can be improved the properties as an anode material for the lithium secondary battery.
