Nanotubular Heterostructure of Tin Dioxide/Titanium Dioxide as a Binder-Free Anode in Lithium-Ion Batteries

Titanium dioxide (TiO2), tin dioxide (SnO2), and heterostructured TiO2/SnO2 nanotube (NT) arrays have been fabricated by template-assisted atomic-layer deposition (ALD) for use as anodes in a lithium-ion battery (LIB). TiO2 NT arrays with 8nm thick walls showed higher capacity (approximate to 250mAhg(-1) after the 50thcycle at a rate of C/10) than the typical theoretical capacity of bulk TiO2 and a radically improved capacity retention property upon cycling. SnO2 NT arrays with different wall thicknesses (8, 10, 13, and 20nm) were also fabricated and their electrochemical performances were measured. All of the SnO2 NT arrays showed substantially higher initial irreversible capacity and higher reversible capacity than those of bulk TiO2. Thinner walls of the SnO2 NTs result in better capacity retention. Heterotubular structures of TiO2 (5nm)/SnO2 (10nm)/TiO2 (5nm) were successfully fabricated, and displayed a sufficiently high capacity (approximate to 300mAhg(-1) after 50cycles) with exceptionally improved cycling performance up to the 50th cycle.