Abstract
Herein, a facile one-step method is developed to in situ prepare crystalline anatase and rutile TiO2 nanocrystals on Ti3C2T x by regulating the metastable Ti ions. The combination of TiO2 nanocrystals and Ti3C2T x not only introduces extensive accessible sites for Na+ storage, but also promotes the charge transport by efficiently relieving the collapse of Ti3C2T x . Compared with pristine Ti3C2T x , the optimized TiO2/Ti3C2T x hybrid electrode (anatase/rutile-TiO2/Ti3C2T x , A/R-TiO2/Ti3C2T x ) exhibits a desirable specific surface area (22.5 m2 g-1), an ultralow charge transfer resistance (42.46 Ω) and excellent ion diffusion (4.01 × 10-14). Remarkably, rich oxygen vacancies are produced on TiO2/Ti3C2T x which is beneficial to enhance the insertion/de-insertion of Na+ during the charge/discharge process. As a result, the A/R-TiO2/Ti3C2T x delivers a high average capacity of 205.4 mA h g-1 at 100 mA g-1 and a desirable capacitance retention rate of 84.7% can be achieved after 600 cycles at 500 mA g-1.