Na3V2(PO4)2F3@bagasse carbon as cathode material for lithium/sodium hybrid ion battery

The nano-scale spherical Na3V2(PO4)2F3 with a NASICON structure phase was prepared with a spray drying technique, and the bagasse in Guangxi, China was selected as the carbon source to prepare Na3V2(PO4)2F3/C. The optimal preparation conditions of the composite determined using thermogravimetry, X-ray diffraction, scanning electron microscopy and electrochemical testing were: a calcination temperature of 650 °C and a 20% carbon source. The Na3V2(PO4)2F3/C has obvious redox peaks, determined by cyclic voltammetry (CV), at 3.90 V and 3.75 V, 4.32 V and 4.15 V. These two pairs of redox peaks correspond to the escape/intercalation of the two pairs of Li+/Na+. Notably, compared with pure Na3V2(PO4)2F3, the specific discharge capacity of Na3V2(PO4)2F3/C-20%, which were used as a cathode material for lithium–sodium hybrid ion batteries, increased from 55 mA h g−1 to 125 mA h g−1, which was an improvement of twofold.