A Novel Titanate As Anode Material for Sodium Ion Batteries

The concern regarding the availability and cost of lithium is raised owing to the fast growth of the markets for lithium ion battery (LIB) and other Li-chemistry based energy storage technologies, such as Li-Air and Li-S systems. Sodium ion battery (SIB) is considered as an alternative technology, due to the potentially low cost and abundance of sodium^[1]. Yet many key components of SIBs, including cathode, anode, electrolyte, still require further improvement.

                 Here we report a new titanate compound as a promising anode material for sodium ion batteries. The compound was synthesized through solid state reaction. Powder X-ray diffraction (XRD) and refinement were applied to investigate the crystal structure. Electron microscopy was used to study the morphology. The electrochemical tests showed high first discharge capacity of >200 mAh/g and ~80 mAh/g reversible capacity in following cycles with good retention, as shown in Figure 1. Ex situ XRD was also performed for fully and partially discharged/charged samples to discover the cycling mechanism and possible reasons for the capacity decay of this material. The influence of synthesis conditions, including temperature, ball mill rate and carbon coating amount were also systematically investigated.