Co3O4 nanotubes, nanorods. and nanoparticles are used as the anode materials of lithium-ion batteries. The results show that the Co3O4 nanotubes prepared by a porous-alumina-template method display high discharge capacity and superior cycling reversibility. Furthermore, Co3O4 nanotubes exhibit excellent sensitivity to hydrogen and alcohol, owing to their hollow, nanostructured character.