Creating an Air‐Stable Sulfur‐Doped Black Phosphorus‐TiO2 Composite as High‐Performance Anode Material for Sodium‐Ion Storage

Abstract With the increasing demand for low cost, long lifetime, high energy density storage systems, an extensive amount of effort has recently been focused on the development of sodium‐ion batteries (SIBs), and a variety of cathode materials have been discovered. However, looking for the most suitable anode material for practical application is a major challenge for SIBs. Herein, a high capacity sulfur‐doped black phosphorus‐TiO 2 (TiO 2 ‐BP‐S) anode material for SIBs is first synthesized by a feasible and large‐scale high‐energy ball‐milling approach, and its stability in air exposure is investigated through X‐ray photoelectron spectroscopy. The morphology of TiO 2 ‐BP‐S is characterized using transmission electron microscopy, indicating that the TiO 2 nanoparticles produce PTi bonds with BP. The TiO 2 ‐BP‐S composite with PS and PTi bonds exhibits excellent stability in air and the superior electrochemical performance. For example, the discharge specific capacity is up to 490 mA h g −1 after 100 cycles at 50 mA g −1 , and it remains at 290 mA h g −1 after 600 cycles at 500 mA g −1 . Meanwhile, the scientific insight that the formation of stable PS and PTi bonds can provide a guide for the practical large‐scale application of SIBs in other titanium base and black phosphorus materials is looked forward.