The Preparation of Bi/Bi₂O₃ Composite Carbon Nanofiber and Its Lithium Storage Performance

In order to improve the cycling performance of Bi anode materials, a method of synthesizing Bi/Bi₂O₃ carbon nanocomposite fibers (Bi/Bi₂O₃(w)-CNFs) was proposed. Bi/Bi₂O₃(w)-CNFs with longitudinal pore structure were successfully synthesized using Bi₂S₃ nanorods as templates based on the electrospinning technique and subsequent high-temperature heat treatment. The composites were characterized with scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The effects of mass fraction of Bi₂S₃ on the structure and electrochemical properties of the composites were discussed. The results showed that the synthesized Bi/Bi₂O₃(8.7%)-CNFs possessed the best lithium storage performance when 8.7%(mass fraction) of Bi₂S₃ was added. At a current density of 0.1 A/g, the Bi/Bi₂O₃(8.7%)-CNFs composites could reach 806 mA·h/g in the first cycle and be stably cycled for 1 000 cycles. Even at a high current density of 5.0 A/g, the lithium storage capacity was still 147 mA·h/g. The structure of Bi/Bi₂O₃(8.7%)-CNFs improved the kinetic performance during charging and discharging, and enhanced the electrochemical performance. The carbon fiber and the internal longitudinal tunnel structure alleviated the volume expansion of the electrode material during the charging and discharging process and enhanced the cycling stability of the battery.