Electrochemical performance of expanded mesocarbon microbeads as anode material for lithium-ion batteries

Expanded mesocarbon microbeads (EMCMB) were prepared from graphitized mesocarbon microbeads (MCMB) by intercalation reaction and rapid heating processes. The morphologies and structural characters of MCMB before and after expansion were compared by SEM, BET and XRD measurements. The electrochemical properties of EMCMB electrodes were examined by a variety of electrochemical testing techniques. It was found that, at high current density EMCMB with appropriate porosity (16-18 m(2) g(-1)) exhibited high reversible capacity (260 mA h g(-1)), with almost 100% capacity retention for up to 50th cycle. The kinetic properties of EMCMB electrodes were characterized via AC impedance measurement. It was indicated that the exchange current density i(0) of EMCMB electrodes was 5-6 times larger than that of MCMB electrode, suggesting the electrochemical activity of MCMB was significantly enhanced by the expansion treatment. (c) 2005 Elsevier B.V. All rights reserved.