preparation of an anatase/rutile-TiO/TiCT hybrid electrode for durable sodium ion batteries.

Herein, a facile one-step method is developed to prepare crystalline anatase and rutile TiO nanocrystals on TiCT by regulating the metastable Ti ions. The combination of TiO nanocrystals and TiCT not only introduces extensive accessible sites for Na storage, but also promotes the charge transport by efficiently relieving the collapse of TiCT . Compared with pristine TiCT , the optimized TiO/TiCT hybrid electrode (anatase/rutile-TiO/TiCT , A/R-TiO/TiCT ) exhibits a desirable specific surface area (22.5 m g), an ultralow charge transfer resistance (42.46 Ω) and excellent ion diffusion (4.01 × 10). Remarkably, rich oxygen vacancies are produced on TiO/TiCT which is beneficial to enhance the insertion/de-insertion of Na during the charge/discharge process. As a result, the A/R-TiO/TiCT delivers a high average capacity of 205.4 mA h g at 100 mA g and a desirable capacitance retention rate of 84.7% can be achieved after 600 cycles at 500 mA g.