Preparation And Application Of Carbon Nanotube Capsules

The self-assembly of carbon nanotubes is a hot topic in these years. Carbon nanotube capsules (CNC), are cage-like hollow capsules and have great potential applications in many fields, including catalyst support, adsorbents, controlled release of materials in drugs and food industry and lithium ion batteries. In this paper, carbon nanotube capsules have been prepared by a W/O emulsion technique via carbon nanotubes self-assembling around water-in-oil droplets by non-covalent hydrogen bonds, Vander Waals action and electrostatic action.In the paper, our researches include the following two parts. The first part involves preparation of carbon nanotube capsules, in which the effects of the content of CNTs in water, the extent of acid treatment and the length of CNTs used, the length of emulsion time and the power of supersonic etc., on the formation and morphology of CNCs were investigated. The structure and morphologies of samples were characterized by FI-IR, SEM and TEM. The second part involves the preparation and electrochemical performances of CNCs /SnO composite, the structures and electrochemical performances of which were investigated by SEM, XRD and a series of electrochemistry techniques. The main results are as follows.The investigation of preparation parameter shows that the surface of CNCs become more compact and smooth, and the shell tends to be thicker, with the amount of CNTs increase, however, too high not to be useful; that long carbon nanotube is useful to wrap and self-assembly of carbon nanotubes; that supersonic method is an effective approach for the large-scale preparation of carbon nanotubes capsules, the compaction and thermal stability of CNC obtained by which are better than that by normal method; and that the diameter of CNC becomes smaller, with the increase of the supersonic power from 200W to 600W, If it is too large, perfect CNC can not be obtained.The cycling performances and charge-discharge profiles of four composites indicated that spherical CNTs are a good matrix of tin-based anode. Their stable capacity is above 400mAh/g, larger than that of carbon nanotube capsules (230mAh/g). The composites by impregnating method have excellent cycling performances, mainly because of the buffering of carbon body during of charge-discharge process.