Lithiation Confined in One Dimensional Nanospace of TiO₂ (Anatase) Nanotube to Enhance the Lithium Storage Property of CuO Nanowires

We have fabricated CuO@TiO₂ nanocable arrays by a facile method involving in situ thermal oxidation of Cu foil and coating of tetrabutyl titanate solution. The structure of the nanocables has been investigated by various techniques to comfirm that the cores are mainly crystalline monoclinic CuO, and the shells are crystalline tetragonal anatase TiO₂. When used as an anode material for lithium-ion batteries, the nanoconfinement effect plays an important role in improving the lithium-ion storage preformance: the lithiation will be confined in one-dimensional space of TiO₂ nanotubes to limit the pulverization of CuO, and the phase interface will cause an interfacial adsorption to enrich more lithium ions at some level. Benefiting from the nanoconfinement effect and interfacial adsorption, the reversible capacity does not fade, but rather increases gradually to 725 mAh g^–1 after 400 cycles at a current density of 60 mA g^–1, superior to the theoretical capacity of CuO.