A high-capacity graphene/mesocarbon microbead composite anode for lithium-ion batteries

The graphene/mesocarbon microbead (MCMB) composite is assessed as an anode material with a high capacity for lithium-ion batteries. The composite electrode exhibits improved cycling stability and rate capability, delivering a high initial charge/discharge capacity of 421.4 mA center dot h/g/494.8 mA center dot h/g as well as an excellent capacity retention over 500 cycles at a current density of 40 mA/g. At a higher current density of 800 mA/g, the electrode still retains 35% of its initial capacity which exceeds the capacity retention of pure graphene or MCMB reference electrodes. Cyclic voltammetry and electrochemical impedance spectroscopy reveal that the composite electrode favors electrochemical kinetics as compared with graphene and MCMB separately. Superior electrochemical properties suggest a strong synergetic effect between highly conductive graphene and MCMB