Structural properties and electrochemical behavior of cone-like TiO2: emphasizing the contributions of structure and spatial arrangement to lithium storage

Abstract

A novel structure of anatase TiO₂, nanocone-like TiO₂ (TiO₂-NC), is successfully prepared by a simple liquid-phase deposition method and is used as an anode material. The morphology and spatial arrangement of the TiO₂-NC greatly affects the lithium storage, and TiO₂-NC achieves a sustained high lithium storage performance (254.7 mA h g⁻¹, corresponding to Li_0.76TiO₂) by assembling the TiO₂-NC into ordered spherical shells. The structural analysis shows that exposed {001} facets of nanosized TiO₂-NC help to increase the surface area as well as shorten the diffusion path of lithium transport. Moreover, an ordered arrangement of the TiO₂-NC with a channel structure can further increase the surface area and improve the diffusion of the electrolyte, hence enhancing the lithium storage. Electrochemical tests indicate that the bulk intercalation of lithium was accompanied by the phenomenon of interfacial lithium storage in the TiO₂-NC. In addition, the polarization of the TiO₂-NC hollow spheres is effectively inhibited due to the ordered structure providing comfortable channels for the ionic and electronic diffusion, which imparts improved rate performance.