ZnSb/C composite anode in additive free electrolyte for sodium ion batteries

• ZnSb/C composite was synthesized by mechanical milling and subsequent heat treatment.
• Electrochemical performances of ZnSb/C without the additive (FEC) were outstanding.
• The performances of ZnSb/C composite was superior to that of Zn–Sb–C mixture.
• Electrochemical reaction mechanism of ZnSb/C composite with Na was suggested.

A zinc antimony composite with carbon (ZnSb/C) was synthesized as an anode material for sodium ion batteries by performing high energy mechanical milling (HEMM) and subsequent heat treatment of Zn, Sb, and Super P. The as-prepared ZnSb/C composite was analyzed with X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), which showed that the ZnSb crystallites are uniformly distributed in the carbon matrix. The ZnSb/C composite was found, despite the absence of fluoroethylene carbonate (FEC), to exhibit a desodiation capacity of 301 mAh g−1 and an initial coulombic efficiency (ICE) of 78% as well as a good cycle life. A Zn–Sb–C mixture prepared with HEMM alone was also compared. The electrochemical reaction mechanism of the ZnSb/C composite was suggested by XRD analyses at several cut-off voltages.