General Layer-By-Layer Approach To Composite Nanotubes and Their Enhanced Lithium-Storage and Gas-Sensing Properties

A novel and versatile layer-by-layer approach has been developed to synthesize composite metal oxide nanotubes on carbon-nanotube (CNT) templates. We demonstrate this approach by the preparation of CeO 2 −SnO 2 and Ag−NiO composite nanotubes. The electrostatic attraction between the CNTs and metal ions play the most important role in the formation of CNT-based core−shell nanotubes, from which the composite metal oxide nanotubes are subsequently synthesized. It is found that the CeO 2 −SnO 2 and Ag−NiO composite nanotubes lead to excellent device performance when they are used in gas sensors and Li-ion batteries, respectively.