Electrochemical Synthesis of Sodium Titanates as Sodium Ion Battery Anode Materials

Sodium ion battery has been extensively studied in recent years because of the availability of sodium sources, and the similar chemistry of sodium compared with lithium. But it is difficult to find a host material that has adequate electrochemical capacity and cyclability for a sodium ion insertion/extraction reaction due to its large radius. [1~3] Herein, we report a simple, fast and controllable route for the electrochemical synthesis of sodium titanates (Na0.23TiO2 and NaTi2O4) from solid TiO2 in molten salts of NaF-NaCl-NaI[4]. This route proceeds by making TiO2 powder into a solid cathode which is then electrolyzed in molten salt. The structure and morphology of sodium titanates are able to be controlled by adjusting the potential and electrolysis time. Then, the product was washed and characterized by XRD and SEM (Fig.1). The electrochemical performance of as prepared sodium titanates were tested with coin-type sodium ion battery. After more than 100 cycles, the capacity is still above 150 mAh /g (Fig. 2). In summary, controllable morphology sodium titanates were prepared by electrochemical synthesis in molten salt, and the as prepared products show good performance as sodium ion battery anode materials