In situ preparation of an anatase/rutile-TiO2/Ti3C2Tx hybrid electrode for durable sodium ion batteries

Herein, a facile one-step method is developed to in situ prepare crystalline anatase and rutile TiO2 nanocrystals on Ti3C2Tx by regulating the metastable Ti ions. The combination of TiO2 nanocrystals and Ti3C2Tx not only introduces extensive accessible sites for Na+ storage, but also promotes the charge transport by efficiently relieving the collapse of Ti3C2Tx. Compared with pristine Ti3C2Tx, the optimized TiO2/Ti3C2Tx hybrid electrode (anatase/rutile-TiO2/Ti3C2Tx, A/R-TiO2/Ti3C2Tx) exhibits a desirable specific surface area (22.5 m(2) g(-1)), an ultralow charge transfer resistance (42.46 omega) and excellent ion diffusion (4.01 x 10(-14)). Remarkably, rich oxygen vacancies are produced on TiO2/Ti3C2Tx which is beneficial to enhance the insertion/de-insertion of Na+ during the charge/discharge process. As a result, the A/R-TiO2/Ti3C2Tx 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).