Expansion of mesocarbon microbeads

Expanded mesocarbon microbeads (EMCMB) were prepared from graphitized mesocarbon microbeads by a chemical method. The expanded volume of EMCMB was significantly influenced by the reaction time, temperature, weight ratio of sulfuric acid and nitric acid, the maximum value of which was 4.1 ml/g. The morphology and structure characters of MCMB after chemical reaction and expansion were also investigated by SEM, BET and XRD measurements. The results show that the spherical, layered structure of MCMB could be verified convincingly by SEM micrographs of EMCMB, and the values of crystallite parameters of intercalated MCMB and EMCMB such as Lc and La decreased significantly compared with that of pristine MCMB, indicating that the stack height and stack width of carbon layers in a crystallite decreased after intercalation reaction and expansion. Meanwhile, EMCMB with appropriate porosity using as anode material for lithium-ion batteries exhibited an excellent high-rate discharge capacity and good cycle stability at the large current density.