Novel template-free synthesis of hollow@porous TiO₂ superior anode materials for lithium ion battery

Template-free method is used to facilely synthesize TiO₂ hollow microspheres via one-step hydrothermal method. Interestingly, the TiO₂ hollow microspheres have porous shell with thickness of about 450 nm. The formation mechanism of the hollow@porous TiO₂ microspheres involves the formation and aggregation of TiO₂ nanoparticles followed by oriented growth, etching of HF, and then Ostwald ripening and transformation process. The prepared TiO₂ microspheres show a reversible capacity of ~170 mAh g⁻¹ after 150 cycles at a current density of 0.6 C and also exhibit a good rate capability of 40.8 mAh g⁻¹ at a current density of 24 C due to the unique hollow@porous structure, which can offer more sites for the storage and insertion of Li ions, and accelerate electrolyte diffusion and Li ions transport. The results also indicate that the as-prepared TiO₂ material possesses excellent electrochemical performances, which may be an ideal anode material for lithium ion battery.