FeBO3 as a low cost and high-performance anode material for sodium-ion batteries

The research of borate materials as sodium-ion batteries (SIBs) anode is still in the early stages, but the boron polyoxoanions are attracting intense interest due to their low atomic weight and high electronegative features. In this work, FeBO₃ was prepared with low-cost raw materials and evaluated as SIBs anode. The FeBO₃ shows a high reversible capacity of 328 mAh/g at the current density of 0.4 A/g. In addition, the electrochemical performance of FeBO₃ can be improved by carbon coating. The prepared carbon-coated FeBO₃ composite has a reversible capacity of 426 mAh/g (at 0.4 A/g) and an outstanding rate capability of 272 mAh/g (at 1.6 A/g). Furthermore, the sodium storage mechanism of FeBO₃ was studied by in-situ XRD and ex-situ XPS.