Chrysanthemum-like TiO₂ nanostructures with exceptional reversible capacity and high coulombic efficiency for lithium storage

The rational design of hierarchically structured materials is of great significance for developing energy-storage devices. Herein, a novel and uniform chrysanthemum-like TiO₂ nanostructure built by well-defined surface-folded nanorods (CLNR-TiO₂) has been fabricated by a facile, effective and template-free synthetic method. By only changing the solvent in the reaction another two different morphologies have been obtained, including flower-like structures built by nanoplates (FLNP-TiO₂) and microspheres (Microsphere-TiO₂). As chrysanthemum-like nanostructures allow efficient Li⁺ ion diffusion, as well as have better structural stability, CLNR-TiO₂ exhibits the best lithium storage performances among the three samples. A superior capacity up to 309.3 mA h g^-1 is achieved at a current rate of 0.5 C (1 C = 170 mA g^-1) for the first cycle with a high coulombic efficiency of 93.4% and it is significant for practical applications. At a high current rate of 5 C, a high reversible capacity of 198.3 mA h g^-1 is obtained in 100 cycles (92% of capacity retention) with excellent rate capacity, high coulombic efficiency and good cycling stability.