Preparation and characterization of carbon nanotubes for energy storage

Multiwall carbon nanotubes (MWNTs) were synthesized using chemical evaporation deposition (CVD). The morphology and microstructure of MWNTs were observed via HRTEM. The multiwall carbon nanotubes are entangled to bundles with a diameter of several tens of nanometers. Electrochemical properties of MWNTs were examined via a variety of electrochemical testing techniques. The MWNTs electrode demonstrated a reversible lithium storage capacity of 340 mAh/g with good cyclability at moderate current density. The kinetic properties of lithium insertion in MWNTs electrodes were characterized via ac impedance measurements. It was found that the lithium diffusion coefficient DLi decreases with an increase of Li-ion concentration in MWNTs electrodes.