2@C nanospheres were synthesized via a template approach. After being sintered under different conditions, two types of polyphase TiO 2hollow nanospheres were obtained. The electrochemical properties of the amorphous TiO 2nanospheres and the TiO 2hollow nanospheres with different phases were characterized as anodes for the Na-ion batteries. It was found that all the samples demonstrated excellent cyclability, which was sustainable for hundreds of cycles with little capacity fading, although the anatase TiO 2presented a capability that was better than that of the mixed anatase/rutile TiO 2or the amorphous TiO 2@C. Through crystallographic analysis, it was revealed that the anatase TiO 2crystal structure supplies two-dimensional diffusion paths for Na-ion intercalation and more accommodation sites. Density functional theory calculations indicated lower energy barriers for the insertion of Na+ into anatase TiO 2. Therefore, anatase TiO 2hollow nanospheres show excellent high-rate performance. Through ex situ field emission scanning electron microscopy, it was revealed that the TiO 2hollow nanosphere architecture can be maintained for hundreds of cycles, which is the main reason for its superior cyclability.