Preparation of Carbon Nano-Onions and Their Application as Anode Materials for Rechargeable Lithium-Ion Batteries

Carbon nano-onions (CNOs) were prepared at 600 degrees C by a simple reaction between copper dichloride hydrate (CuCl(2)center dot 2H(2)O) and calcium carbide (CaC(2)). The morphology and structure of the obtained products were investigated by field-emission scanning electron microscope, high-resolution transmission electron microscopy, X-ray diffraction, Raman spectrum, and nitrogen adsorption. Large quantities of CNOs consisting of quasi-spherically concentric graphitic shells with high purity and uniform size distribution (about 30 nm) were obtained. The crystal water in CuCl(2)center dot 2H(2)O plays an important role in the formation of CNOs. The CNOs as-obtained exhibit high capacity and excellent cycling performance as anode materials for lithium-ion batteries, which can deliver a reversible capacity of 391 mAh g(-1) up to 60 cycles.