One-pot synthesis of bicrystalline titanium dioxide spheres with a core–shell structure as anode materials for lithium and sodium ion batteries

Abstract

Bicrystalline titanium dioxide spheres (anatase@TiO2(B) spheres) with enhanced electrochemical activity in lithium and sodium ion batteries have been successfully synthesized via a facile one-pot solvothermal method. The anatase@TiO2(B) spheres have a core–shell structure with TiO2(B) nanosheets sheathing the anatase TiO2 sphere core which consists of nanoparticles, as characterized by X-ray diffraction, scanning electron microscopy (SEM), and high-resolution transmission microscopy (HRTEM). The anatase@TiO2(B) spheres show excellent lithium storage performance, which have high initial discharge capacity (114.8 mAh g−1) with almost no capacity fading after 100 cycles and still maintain at 91.7 mAh g−1 after 375 cycles at a super-high current density of 5040 mA g−1 (30 C). What's more, they also show excellent rate capability in sodium ion batteries at various current densities ranging from 85 to 850 mA g−1. The unique hierarchical structure of anatase@TiO2(B) spheres with excellent cycle performance and rate capability make a compelling case for their development as anode materials for both lithium and sodium ion batteries.