Dual-phase TiO2 hollow microspheres as a superior anode for sodium ion battery

Abstract

Nanoparticles of TiO 2 -MS with size of ∼500 nm have been fabricated and shows excellent long-term cycling stability. • Nanoparticles of TiO 2 -MS with size of ∼ 500 nm is prepared by a simple approach. • The nanostructural can accelerate the reaction kinetics of TiO 2 . • TiO 2 -MS electrode exhibits excellent electrochemical performance. • Dual-phase anatase/TiO 2 -B hollow microspheres were beneficial to enhancing the storage of Na +. TiO 2 is considered as a potential anode with the advantages of stable structure and high safety. However, the large-scale application of TiO 2 is restricted due to its low electronic conductivity and sluggish Na + diffusion. In the present work, anatase and TiO 2 -B dual-phase TiO 2 hollow microspheres (TiO 2 -MS) were designed through a universal hydrothermal reaction. These microspheres were composed of nanosheets, and the nanosheets were consisted of small nanoparticles. Benefitting from the synergistic effect of dual-phase TiO 2 nanoparticles and hierarchical structure, the TiO 2 -MS can not only buffer the volume changes during Na + intercalation/deintercalation process, but also provide the contact space for electrolyte − electrode. As a result, the TiO 2 -MS anode delivered a distinguished sodium storage performance, maintained 240 mA h g −1 at 2C (1C = 168 mA g −1 ) after 150 cycles. Even the current density was increased to 20C, a capacity of 159.7 mA h g −1 can still be maintained after 5000 cycles.