3D-Assembled rutile TiO2 spheres with c-channels for efficient lithium-ion storage.

Three-dimensional (3D) TiO2 architectures have attracted significant attention recently as they can improve the electrochemical stability and realize the full potential of TiO2-based anodes in lithium ion batteries. Here, flower-like rutile TiO2 spheres with radially assembled nanorods (c-channels) were fabricated via a simple hydrothermal method. The 3D radial architecture affords massive active sites to fortify the lithium storage. Moreover, the presence of c-channels facilitates electrolyte infiltration and offers facile pathways for efficient Li+ transport. As a result, this flower-like rutile TiO2 anode gives significantly enhanced specific capacities (615 mA h g−1 at 1 C and 386 mA h g−1 at 2 C after 400 cycles) and a superior long-term cyclability (up to 10 000 cycles with a specific capacity of 67 mA h g−1 at 100 C). Kinetic analysis reveals that the enhanced diffusion-controlled and surface capacitive storage leads to the excellent electrochemical behavior. This work not only exhibits the enormous advantages of 3D architectures with c-channels, but also provides access to structural design and crystal phase selection for TiO2-based anode materials.